NYSGA 1956
GUIDEBOOK FOR FIELD TRIPS
IN
WESTERN NEW YORK
MAY 4-6, 1956
TWENTY EIGHTH ANNUAL MEETING
NEW YORK STATE
GEOLOGICAL ASSOCIATION
AT THE
UNIVERSITY OF ROCHESTER
ROCHESTER, NEW YORK

1A: SILURIAN STRATIGRAPHY, GEOMORPHOLOGY
by U of R Students and Staff
The two stops on this trip will afford an opportunity to study the classic Lower and Middle Silurian stratigraphic section of the Rochester area. The route to and between the stops passes many features related to the glacial history of the region (see pp. 47-60) and to the history of the Genesee River (see pp. 5-8).

1A: SILURIAN STRATIGRAPHY, GEOMORPHOLOGY

Post-glacial Genesee
Zero mileage (headed south) at River Boulevard entrance to main quadrangle of U of R River Campus. Erratic anorthosite boulder opposite entrance, With polished and striated surfaces, bears bronze tablet inscribed with "The Genesee", alma mater of the University of Rochester. Proceed south on River Boulevard. River here is in post-glacial course (see p. 8).

West end of Pinnacle Range
For first 3.5 miles, route nearly parallels the Pinnacle Range (see p. 56) of kame moraine hills. Route is on outwash plain and lake beds. U of R Campus is on west end of range.

Mt. Hope Cemetery
Mt. Hope Cemetery to left (N). Northwestern portion of cemetery, adjoining campus, is an area of spectacular kame and kettle topography.

View of Pinnacle Range
View to left (N) of Pinnacle Range, now about a half-mile to the north.

Colgate-Rochester Divinity School
Enter town of Brighton. Colgate-Rochester Divinity School on crest of Pinnacle Range to left (N).

Highest point on Pinnacle Range
Highest point on Pinnacle Range (749 feet) is just west of radio and telephone towers visible here to the left (N).

Pass over Rochester subway
Pass over Rochester subway, in abandoned bed of early Erie Canal.
Now occupied by Interstate 490...

Lockport Dolomite
Pass under New York Central main line. Outcrops are Lockport dolomite showing characteristic pitted and pocketed surface weathering.

Irondequoit Valley
Flat bottom of Irondequoit Valley (e1ev. 270 feet). Valley is part of preglacial Genesee Valley (see p. 7) which here was filled with morainal debris and Lake Iroquois (see p. 54) sands, then re-excavated by post-glacial Irondequoit Creek. Bedrock, till and lake deposits are exposed at places along valley sides; local sand and gravel workings in glacial material and lake beds. Valley slopes marked by several terraces representing levels of Lake Iroquois. One terrace (at 400 feet) visible here forms flat valley rim.

View of Rochester
View to left (w) to Rochester over Irondequoit Valley and in line with Pinnacle Range which is prominent elevation.

Orchards
Next six miles. Orchards here are part of extensive apple and peach belt south of Lake Ontario.
2010: Orchards are now pretty much gone, replaced by suburban sprawl...

STOP 1. Penfield Quarry
Penfield Quarry of the Dolomite Products Co.
The Lockport dolomite is a hard, dark gray, dolomitic limestone, with considerable quantities of disseminated argillaceous matter. A fine to coarse sugary texture and strong petroliferous odor when struck with a hammer are characteristic. The formation is about 180 feet in total thickness, of which about 42 feet are exposed in the quarry wall. The Lockport underlies much of the city of Rochester. It has been used as a building stone but weathers with moderate rapidity. The sometimes fantastically shaped and sculptured blocks resulting from solution by subsurface water are commonly used for ornamental stonework in local gardens. Commercially the rock finds its greatest value today as crushed stone, for which it is quarried in two large quarries operated hy the Dolomite Products Company just outside of Rochester, and by smaller concerns at other localities along its outcrop belt.
Bedding is massive; fossils occur in some layers but are not usually well preserved. Solution cavities and stylolites are common. In the upper levels of the Penfield quarry many of the secondary cavities are filled with crystallized dolomite and other minerals; small fissures may be filled with sphalerite, gypsum, or galena, and residual hydrocarbons occur. For greater detail see comments under Field Trip No. 3C; on that trip there will be opportunity to collect from blocks of the mineral-bearing strata.

Lake Iroquois bar
Ridge Rd. goes to right (E) on Lake Iroquois bar which is inconspicuous here. See mileage 25.5.

Barrier bar
East end of barrier bar carrying road across mouth of Irondequoit Bay which occupies part of re-excavated pre-glacial Genesee Valley.

West end of barrier bar.

Durand-Eastman Park
Durand-Eastman Park, Rochester's largest public park, is in an area of glacial till veneered with Lake Iroquois deposits. The terrane has been dissected deeply by a number of small and closely spaced post-glacial streams which flow directly into Lake Ontario or into narrow inter-divide lakes now sealed from Lake Ontario by massive barrier bars. The Lake Ontario surface is at 246 feet. The crests of the divides increase gradually in elevation southward from about 300 feet a little south of the lake shore to 375 feet two miles farther south.

Two barred lakes
Public bath house to right (N). Two barred lakes south of road.

Narrow divide
For 1.4 miles route follows narrow divide between steep-sided valleys. Note accordant divides (Lake Iroquois bottom) at about 375 feet.

Bottom of Lake Iroquois.
Next mile: Cross near-shore bottom of Lake Iroquois.

Offshore bar
Road is atop offshore bar of Lake Iroquois.

Lagoon
Note lower ground to left (S), lagoon behind barrier bar.

Stop sign. Traffic circle.
Stop sign. Traffic circle. Take third street to right (first one past bridge) where sign says "Norton St. Traffic Turn Here".
2010: Traffic controls are much different now, but this path takes you to Norton Street.

Private Road
Gateway to entrance to Rochester Gas and Electric Company private road to power plant. Park.

STOP 2. Rochester Gorge.
Exposures along private road to Rochester Gas and Electric Company power plant, and in banks of Genesee Gorge.
Bedrock.--Exposures in the new road cut extend from the Queenston shale to the Reynales limestone (Clinton group). Strata above the Reynales, up to the basal few feet of Rochester shale are exposed in the gorge wall below the Hawk-Eye plant of Eastman Kodak Company.
The contrasting lithologic types exposed in the road cut exhibit a variety of sedimentary features reflecting diverse environments (see pp. 9-15). The accessible section here is not generally fossiliferous, beds of Pentamerus coquina provide the best collecting possibilities.
The thin Thorold sandstone forms the lower falls of the Genesee at the power plant, just south of Driving Park Avenue bridge. The middle falls, a short distance farther upstream is formed by the Reynales limestone. The upper falls, not visible from this locality, is over beds in the lower part of the Lockport dolomite.
The accompanying stratigraphic section is based on exposures in this vicinity.
Gorge.--The river gorge here (200 feet deep at this point) is a result of post-glacial erosion. The pre-glacial course at this latitude lay several miles to the east in what is now the valley of Irondequoit Bay and Creek. See page 5 for river history.
Unconsolidated material.--Above the Silurian strata in the upper portion of the road cut are exposed four distinct types of unconsolidated materials with a cumulative thickness of approximately 25 feet and length of exposure of 200 feet. The exposure of these deposits is bounded on the northeast by a graded slope and on the southwest by an undisturbed vegetative covering. The exposure strikes N60°E.
Lowermost of these unconsolidated units at the head of the road cut is a 4- to 5-foot layer of reddish till lying on striated and highly polished Reynales limestone. Striations on the limestone surface strike N 85°E, an anomalous direction for this region. The red till contains striated and well worn pebbles with relatively little sharply angular material. Components of the till range in size from small boulders to clay sized particles, no stratification is apparent. The materials are extremely fresh without visible alteration of any type. Fabric studies of this till show a distinct northwest-southeast preferred orientation of the long-diameter of pebbles.
This unit of unconsolidated sedimentary material extends from the head of the road cut for a distance of 120 feet toward the southwest. At this point it terminates abruptly against Sodus shale, the next stratigraphic unit above the Reynales Formation.
Immediately overlying the red till and in marked contrast to it in the northwest portion of the sequence is approximately 10 feet of highly modified, bouldery material in a jumbled mass. Percolating ground water solutions have altered or disintegrated all types of rock and material, coating and replacing material with various iron oxides. Contained within this unit at a point 100 feet from the head of the cut is a lens or nest of stratified sand 8 feet wide and with a maximum thickness of 2 feet. Any other primary textural or structural modifications within this unit have been destroyed by the alteration of the material. This altered material bevels across the red till-shale contact and, in part, lies directly on the Sodus shale.
At a point about 110 feet southwest along the exposure another type of material wedges in below the highly weathered sediment and overlies the Sodus shale. This is a brown sandy unit containing blocks of limestone and other coarser material along with small lenses and stringers of sand. Weathering of this material has been limited to various stages in the alteration and disintegration fragments into patches of yellow-brown residuum. Thickening of this member increases to the southwest at the expense of the highly altered material which correspondingly pinches out in the same direction.
Lying above and again sharply contrasting with the underlying material is 10-15 feet of ashy rubbish exposed throughout the cut. This represents the remains of a city dump. The thickness of this material lessens to the southwest; solutions from it may, in part, account for the alteration of the underlying material.

Lunch Stop
LUNCH STOP at park pavilions. End of trip

1B: GLACIAL GEOLOGY
by U of R Students and Staff
Stops on this trip will be in the Mendon Ponds kame and kettle area (see p. 55) and on the Pinnacle Range of kame moraine hills (see p. 56). The trip ends adjacent to the post-glacial lower gorge of the Genesee River.

1B: GLACIAL GEOLOGY

Drumlins
Note drumlins elongated parallel to N.Y. 65 both east and west of the route.

STOP 1. Gravel pit in kame moraine
Gravel pit in kame moraine, exposing features typical of such deposits in this area. Lenses of sand and gravel show great variety of sedimentary features. The sediments are displaced along small normal faults in places. The gravel lenses tend to be cemented with calcareous material probably derived from pebbles and cobbles of Lockport dolomite. Most abundant pebbles are of red Grimsby sandstone; however, representatives of all formations of the local Lower and Middle Silurian section can be found. In addition there are Ordovician limestones (some fossiliferous) and crystallines from Canada.

STOP 2. Mendon Ponds County Park
In Mendon Ponds County Park are to be seen excellent examples of kame hills, kettles, eskers, and lakes and swamps in poorly drained morainal ground. For general glacial history see pages 47-60; for more specific comments on this park, see page 55. There are two prominent eskers in the park, one east and one west of Hundred Acre Pond which is the largest of several ponds. The recognizable portion of the western esker extends, with only slight interruptions, for a little over two miles. The group will walk along about 0.3 mile of this esker, from a point behind (S) of the park buildings to a conspicuous kettle known as Devil's Bathtub, at which point the esker deposits fan out, apparently at the mouth of the stream responsible for the deposit.

Swamp
Swamp-filled depression to left (N) here continues north to Hundred Acre Pond

Kame-kettle area
Next 1.2 miles. At sharp left curve begins extensive kame-kettle area east of Hundred Acre Pond depression

Eastern esker
Steep slope east (right) of route is eastern esker. Hundred Acre Pond to left (W).

Western esker
Road crosses small swampy area here, then rises abruptly, cutting through the western esker at point about 0.8 mile north of where group climbed upon it at Stop 2.

STOP 3. Cobbs Hill
Cobbs Hill is the easternmost prominent hill of the Pinnacle Range (see p.56). In clear weather an excellent view may be obtained from here. Water elevation 633 feet, about 130 feet above plain to north and south. Water in reservoir is from Hemlock Lake, about 30 miles south of Rochester. To south lie outwash plains and glacial lake beds, with occasional drumlins. Bedrock hills (Bristol Hills, Middle Devonian) rise in distance; Onondaga escarpment not prominent here. To north lies city of Rochester on thin veneer of lake beds and till above Lockport dolomite and Rochester shale. Lake Ontario in distance. To west Pinnacle Range continues toward U of R River Campus. Radio and telephone towers are on the Pinnacle, highest of the Pinnacle Hills, just east of summit.

Pinnacle Range
Route follows along south foot of Pinnacle Range.

STOP 4. Quarry in Pinnacle Range kame moraine.
Sand and gravel quarry in Pinnacle Range kame moraine. The lower part of the cut exposes uniform, well-sorted and stratified sands; bedding southwest at 25~28 degrees. At the upper part of the cut there is a thin covering of till, evidencing brief ice re-advance after kame formation. Fabric studies of the orientation of the long axes of pebbles in the hill show, at the east end of the exposure, an 11% concentration with a plunge of 10 degrees and a southward strike, and at the west end, a dominant plunge of 20-25 degrees and strike concentration in the sector from S30°W to S15°E. The low ridge bordering the ball park on the northwest (old cemetery beyond the concessions stand) is also composed of till.

Erie Canal bed
Cross Rochester subway in old Erie Canal bed.
2010: All is changed, but the path here still takes you close to what the road log says.

Lunch Stop
LUNCH STOP at park pavilions. Park is on east bank of lower gorge (postglacial) of the Genesee River downstream from lowest falls. See pages 4-8. END OF TRIP lB

1C: TOUR OF KODAK PARK
by U of R Students and Staff
Kodak Park, the main plant of the Eastman Kodak Company, is located at Ridge Road and Lake Avenue, a short distance west of the Genesee Gorge opposite Seneca Park. Buses will proceed from the lunch stop directly to Kodak Park via the Veterans' Memorial Bridge (Ridge Road, U.S. 104). After the tour, buses will return directly to the U of R River Campus
No road log

2: DEVONIAN STRATIGRAPHY; HISTORY OF GENESEE RIVER
The route of this trip extends from the U of R River Campus southward, up the Genesee River Valley, about 50 miles to Letchworth State Park and return. The Genesee River will be seen in both its pre-glacial and post-glacial valleys, including the scenic gorge through Letchworth Park and its history reviewed (see pp. 4-8). Middle and Upper Devonian strata (see pp. 26-46) will be seen at four stops, with opportunity for fossil collecting in rocks of the Hamilton group at two of them. One stop will be a visit to the Mount Morris flood control dam.

2: DEVONIAN STRATIGRAPHY; HISTORY OF GENESEE RIVER

Drumlin to left
Drumlin to left. Route leaves river bank and crosses drumlin at 4.9 miles. A number of the drumlins in this area have wave-cut northern ends developed while partly submerged in glacial lakes (see p. 49).

Top of Drumlin

Two drumlins
Two prominent drumlins to right (SW), one wooded.

Meander bend of Genesee
Meander bend of Genesee River adjacent to road (right). Here route begins to follow pre-glacial valley of Genesee, now with broad flood plain developed on partial filling of glacier-transported debris. Just north of this point, pre-glacial course swung eastward along outcrop belt of soft Upper Silurian shales, and eventually turned northward again in line with present Irondequoit Valley (see pp.. 5-8 and map on p. 4). Except for Irondequoit Valley, the pre-glacial valley north of this point is entirely filled with debris and is without surface expression, the course has been fairly accurately traced through water well records ..

Onondaga limestone
Bridge across stream with outcrops of Onondaga limestone about 150 feet east of road. The Onondaga escarpment has no particular expression at this point because of local prominence of slopes into Genesee Valley ..

Conesus Creek
Bridge over Conesus Creek, outlet for Conesus LaKe

East side of Genesee Valley
Begin ascent of east side of Genesee Valley. Good views to west (right) across valley. This is pre-glacial section between Mt. Morris and Avon (see p. 7).

North branch of Jaycox Run
Small bridge across north branch of Jaycox Run (Wheeler Gully). Road bends slightly right. Menteth limestone exposed in low falls immediately left (E) of road, also as one-foot bed at top of cut in stream bend to right. Shales in stream bend are Deep Run member, Ludlowville formation.

Falls over Tichenor
Falls, 40 feet high, over one-foot bed of Tichenor limestone about 400 feet west (right) of road

STOP1. Jacox Run
Section exposed in stream bed 0.25 mile west of road is as follows:
Moscow formation
Menteth limestone member - impure limestone, makes low falls | 1'
Ludlowville formation |
Deep Run shale member - calcareous shale and thin argillaceous limestones | 11'
Tichenor limestone member - crinoidal limestone, fall-maker | 1'
Wanakah shale member - calcareous shale with thin limestones
and prominent 1-foot limestone bed about 10 feet from top
49'
Excellent fossil collecting in Deep Run shale and shales of Wanakah member. Crinoid columns conspicuous in Tichenor limestone; this is one of the "Encrinal" layers of early reports. See pp. 31-38 for stratigraphic details and faunal lists.

View of Retsof mine shaft
Currently operating shaft of Retsof mine of International Salt Company visible to west across valley. This is reportedly the largest salt mine in the world. A single 9-foot layer of rock salt (in the Camillus facies of the Salina) is being mined at a level 1000 feet below the surface 'at the shaft. The face now being worked is about 2.5 miles from the shaft. An area about 15 miles in circumference has been mined by the room and pillar system, leaving about 60% of the salt in pillars. Mining began in 1885 at a shaft 3 miles south of Retsof (see mileage 78.3). The shaft at Retsof was opened in 1920.

Good view to west.
N.Y. 63. Turn left. After turn, good overlook of valley to west.

Fall Brook to right.
Fall Brook to right (W). Lower end of valley will be Stop 4, this trip. Falls is over Genundewah limestone at base of West River formation (see p. 41).

Breech in west wall of Genesee Valley
Breech in west wall of Genesee Valley, visible in right (W) distance across valley and just to right of water tower and smokestack, is debouchure of post-glacial Genesee from Mt. Morris canyon (see p. 7).

Canaseraga Creek
Bridge over Canaseraga Creek, the misfit stream presently occupying wide Dansville Valley (see p. 5). Route here begins to cross wide flat floor of this valley, originally cut by pre-glacial Genesee, then deepened by ice-gouging and partly filled with rock debris and lake deposits.

Climb out of valley
Route climbs from valley floor, cross railroad. Enter Mt. Morris.

Overlook of Mt. Morris canyon to left.

STOP 2. Mount Morris Dam
Built by Corps of Engineers, completed 1951. Purpose: flood control. Concrete construction using filler of crushed Onondaga limestone from General Crushed Stone Company quarries at LeRoy (20 miles north) and sand from glacial lake delta just north of gorge (see mileage 73.8). Total length of dam: 1028 feet, length of spillway: 550 feet. Drainage area above dam: 1077 sq. miles, maximum reservoir areag 3300 acres. Capacity at spillway elevation: 337,000 acre feet. The base of the dam rests upon the Genundewa limestone at the base of the West River shale (see p. 41). The section exposed in the gorge is as follows:
Glacial cover |
Rhinestreet black shale -- laminated, fine-grained shale, making buttresses at gorge rim | 53'
Cashaqua formation -- gray-green shales and thin siltstones, easily weathered and making the long slope of the gorge wall | 121'
West River shale -- dark, thin-bedded shale at foot of gorges> only part exposed | 65'
The Rhinestreet and Cashaqua and the contact between the two are excellently exposed in the cuts of the road leading down to the deck of the dam.

View of Dansville Valley
To the southeast (left front) can be seen the broad Dansville Valley extending into the distance and, to the right of it, in front of the high ground, the Nunda Valley which was cut by the pre-glacial west branch of the Genesee and is now occupied by misfit Keshequa Creek. See pages 4-70

Begin descent into Nunda Valley

Keshequa Creek
Keshequa Creek, misfit stream to left of route.

Locks of abandoned canal
Locks of abandoned canal constructed to carry river traffic from Portageville to Mt. Morris via the Nunda Valley, around post-glacial gorge section of present Genesee River. Canal operated 1852-1877. Lock walls are constructed of Nunda sandstone (see p. 45); typical gray-green flagstone blocks.

Ascend morainal dam
Begin to ascend morainal dam which blocked Genesee from pre-glacial Nunda Valley. Route crosses moraine from here to Portageville.

Descend slope of Portageville moraine
Descend slope of Portageville moraine into pre-glacial Genesee Valley. Good view of valley to left (S)

Genesee River
Bridge over Genesee River. River elevation 1100 feet

View of Genesee River
Railroad overpass. To north (R) Genesee River can be seen where it leaves broad pre~glacial valley and enters narrow post-glacial gorge section.
2010: Railroad is gone, but this should be where it used to be.

Upper Falls
Erie Railroad bridge across gorge. Uppermost of three falls in gorge just north of bridge (height 71 feet) fall-maker in basal Nunda sandstone (see p. 7). Roadcut exposures are Nunda.

STOP 3. Bench between Middle and Upper Falls
Parking area. LUNCH stop. This flat area is a small terrace bench between the middle and upper falls. The middle falls, highest of the three in Letchworth Park, drops 107 feet. Fall maker is resistant layer in Gardeau formation (see p. 45). The lower falls will not be visited.

Good view of middle falls as route ascends hill

Nunda Sandstone
Roadcut outcrops of Nunda sandstone. Bronze tablet to James Hall.
2010: The tablet, placed in 1908, is probably no longer here. A replica was on display at the museum for a time.

Gorge overlook.
Gorge overlook. Camera stop. Gorge wall is Gardeau formation

Wolf Creek

Road cut to right exposes glacial lake sands

North overlook of Mt. Morris Dam is to right

Small Delta
Excavations in small delta built into glacial lake filling Genesee Valley (elev. about 800 feet). Some of sand for dam concrete obtained here.

Re-enter wide pre-glacial valley
N.Y. 36. Turn left (N). Genesee River leaves gorge section and re-enters wide pre-glacial valley 0.25 mile south of this point. Road route now follows along west edge of valley to Leicester.

Type section of Moscow Fm.
In east bank of stream (Little Beards Creek) a quarter-mile north of here is type section of Moscow formation of Hamilton group

Abandoned mine buildings
Sharp right turn in Cuylerville. To left, after making turn, can be seen abandoned shaft head buildings of the International Salt Company mine. Only a small ventilator shaft operates here now; active shaft is about 3 miles to the north. Route now crosses flat floor of broad Genesee Valley.

Genesee River

STOP 4. Fall Brook
Park just past abandoned buildings on right.
This is the type section of the Geneseo black shale (village of Geneseo just to the north) and also affords excellent exposures of the overlying Genundewah and West River and the underlying Leicester marcasite and Windom shale members of the Moscow formation. See pages 35, 39.
The more calcareous layers of the Windom are richly fossiliferous; some large concretions occur. The Moscow-Geneseo contact is marked by the thin but unusual Leicester marcasite which has a Hamilton fauna described as dwarfed or interpreted to consist of small fossils as a result of sorting (Loomis, 1903; Tasch, 1953). Where the lenses of Leicester are absent, the contact is marked by iron staining. The conspicuous laminated bedding and smooth jointing of the Geneseo contrast with the less regular structures of the Windom. The Geneseo is almost unfossiliferous. Large blocks of the fall-making Genundewah limestone show its characteristic lithology; most blocks are replete with the pteropod (?) Styliolina fissurella.

Geneseo black shale
Geneseo black shale with limestone bands and layers of concretions in road cuts.

Trip back goes over same route
Junction N.Y. 63. Turn left. Route from here back to U of R campus follows course of start of this trip from 0.0 to 28.7 miles.

3A: HAMILTON STRATIGRAPHY AND FOSSIL COLLECTING
Exposures of the Ludlowville formation will be visited in an area south of Batavia. The Centerfield member here is prolifically fossiliferous and the relationships of the other Ludlowville members (except the Deep Run) are clearly shown across the Clarendon-Linden monocline

3A: HAMILTON STRATIGRAPHY AND FOSSIL COLLECTING

Ascend Dumpling Hill drumlin
Road swings away from Genesee River. Ascends Dumpling Hill, a drumlin whose northeast end is truncated by the Genesee

Now over Silurian
Turn right (W) on North Rd. at beginning of settlement (Scottsville). Now over Upper Silurian; no exposures

Gravel pits
Scottsville-Chili Rd. Keep straight. Several gravel pits in glacial material to left after crossing

Wooded Drumlin
Stop sign. N.Y. 383. Turn right (W). Wooded drumlin at left after making turn. Behind (S of) drumlin is shallow gypsum mine in Upper Silurian, Plant-visible at 15.3 miles

Oatka Creek bridge.
Creek here runs west-to-east along south edge of outcrop belt of soft Upper Silurian shales. Rise of ground just south of creek in Onondaga escarpment, here supported by water limes above Salina shales and by lower part of Onondaga limestone ..

Quarry in Onondaga Limestone to right
Quarry and crushing plant of General Crushed Stone Company to right. Operating in Onondaga limestone

Enter Village of LeRoy, birthplace of Jell-O!

Bridge over Oatka Creek.
Low dam retains pond to left. To right, just north of bridge, is low falls over Stafford limestone member of Marcellus formation, Hamilton group. Banks below buildings on east (right) side of creek below falls used to expose type section, Oatka Creek black shale member of Marcellus (typical Leiorhynchus facies: paper-like black shales with Leiorhynchus and Orbiculoidea. Bank is now parked and exposures are poor.

Levanna member, Skaneateles fm
Outcrops in stream bank to left (SE), adjacent to small bridge on side road, are Levanna shale member of Skaneateles formation.

STOP 1. East Bethany fossil site
Exposures of Hamilton strata along Delaware, Lackawanna and Western Railroad and vicinity, 3 miles west of East Bethany.
This locality is world famous as a collecting ground for Middle Devonian fossils of the typical Hamilton assemblage (see pp. 37-38). The locality is also interesting for structural features, unusual in western New York, which have led to the exposure of over 100 feet of strata in a relatively short, nearly horizontal exposure. The section to be visited extends along railroad cut and hillside exposures for about half a mile east of the bridge carrying Francis Road over the railroad tracks. In this distance the section spans, nearly completely, the Clarendon-Linden monocline, a westward-sloping flexure which displaces the exposed strata about 100 feet. Observable dips at the surface reach a maximum of about .5 degrees. Water and gas well records suggest a greater displacement at depth, and it may be that the monocline evidenced at the surface is but a subdued expression of a major fault at depth.
The stratigraphic section here is as follows (see pp. 30-34):
Ludlowville formation |
| Tichenor limestone | about 1'
| Wanakah shale | 1.5'
| Ledyard shale | 88'
| Centerfiled shale | 2' (+?)
Skaneateles formation |
| Levanna shale | portion near top
The accompanying map and perspective sketch indicate the field relations. The letters in the following discussion refer to these illustrations. The Levanna shale (A) is in typical black shale, Leiorhynchus facies, exposed in the stream bank. The Levanna-Centerfield contact is covered and the actual thickness of the Centerfield cannot be determined. Unweathered blocks occur in place, with horizontal bedding at B, and from here eastward for more than a mile. Most of the material in this cut is weathered Centerfield residuum rich in fossils. At C fresh Centerfield strata occur in the stream bed about 30 feet lower than at B, and in between the two (D) the ground surface is composed almost exclusively of fossils weathered from the Centerfield and washed clean of matrix. Samples of the finer fraction of material here are rich in microfossils: ostracods, sponge spicules, Foraminifera, Bryozoa, crinoid and echinoid plates and spines, immature specimens of larger forms (and oddly shaped cinders!). The larger specimens are mostly corals, brachiopods, gastropods, and crinoids in great variety, and the trilobite Phacops rana.
Severe weathering of a portion of the Ledyard bearing fossils formerly replaced with marcasite has yielded an interesting assemblage of limonitized specimens at E. Most common are small gastropods and nautiloids, the goniatite Tornoceras, and nuculoid pelecypods.
Middle layers of the Ledyard, exposed in the railroad cut F, are poorly fossiliferous. Leiorhynchus and Chonetes occur in some of the laminated black shales in this cut. A rather high angle reverse fault (displacement a few feet, dip east) is visible here.
The upper portion of the Ledyard, and the Wanakah, in cuts on both sides of the railroad at G, typify the calcareous shale facies of the Hamilton. Occurring here are Rhipidomella, Athyris, Atrypa, Mucrospirifer, Ambocoelia, Stereolasma, Pleurodictyum, Styliolina. Microfossils are abundant, also, in washed residues of thoroughly weathered material, but variety is less than in samples from the Centerfield. Some of the more coherent layers contain orthoconic nautiloids, gastropods and pelecypods, along with the trilobites Greenops and Phacops.
The resistant lime-rich layer which descends to track level just west of the bridge abutment is the "Strophalosia" bed, replete with the productid brachiopod Productella truncata (formerly Strophalosia). This has been used as the marker horizon separating the Ledyard below from the Wanakah above. This practice is of questionable validity (although followed here for convenience), for the bed does not occur in a consistent position with respect to the top and bottom of the Ledyard-Wanakah shale interval in different exposed sections (see p. 34). At this locality it is unusually high, thus making the thickness of the Wanakah unusually small and that of the Ledyard correspondingly great. It is probably better to consider the Ledyard-Wanakah a single unit with several contrasting facies between the Centerfield and Tichenor 1imestones.
An exposure near the top of the Wanakah, at H, is rich in Chonetes, Mucrospirifer and Pleurodictyum. A little higher on the slope in the same area, tetracorals probably weathered from the Tichenor can be found.

3B: SILURIAN-DEVONIAN CONTACT RELATIONS
Oaks Corners Quarry
The highest Silurian strata (Bertie and CobleskillJ see p. 18), the lowest Devonian strata (Onondaga, see pp. 21-26), and the disconformable contact between them will be examined at a locality near Phelps, N.Y.

3B: SILURIAN-DEVONIAN CONTACT RELATIONS

Pass under railroad. Erie Canal to left.

Sand and Gravel quarries
Gravel and sand operation in water-laid glacial material to right.

Kame-moraine area
High ground to left is western edge of large kame moraine area (Turk Baker Hills, see p. 55).

Gravel pit
Gravel pit in kame material to left

Victor Channel
For next few miles route runs along northern margin of Victor channel, cut by waters flowing parallel and close to the ice front. Onondaga limestone caps high ground to south of valley.

Drumlins and Onondaga escarpment
Next 5.8 miles: The route here runs about a mile south of the southern edge of the great Palmyra drumlin field. Some of the southernmost drumlins are visible to the left (N). The high ground to the right (S) is the Onondaga escarpment, rather feebly developed here.

Cross Canandaigua Lake outlet.

Stone fences
Stone fences are of platy waterlime of Bertie formation

Gravel pit to right (S)

Onondaga escarpment
Clifton Springs to right (S). Rise in ground is Onondaga escarpment

Onondaga outcrop belt
Slight rise in route elevation marks passage onto Onondaga outcrop belt. Note Onondaga blocks in stone fences

Bertie outcrops
Cross Flint Creek. Bertie outcrops in stream bed.

STOP 1. Oaks Corners Quarry
Oaks Corners Quarry and Plant of General Crushed Stone Company. The stratigraphic section exposed here is as follows (measurements from Oliver, 1954):
Onondaga limestone |
| Moorehouse member: medium- to thick-bedded limestone with dark chert | 36'
| Nedrow member: thin-bedded impure limestone with chert | 16'
| Edgecliff member: light gray crystalline coralline limestone, with pebbles of Cobleskill and intermittent sandy zone at base | 10' &plusmn;
Disconformity: Relief up to 5 feet along irregular surface. Contact has been locus of much solution and it is difficult to judge how much of the relief of the contact surface is due to pre-Onondaga erosion and how much to post-depositional solution. Lower Devonian Helderberg-Oriskany sequence missing
Cobleskill formation, Akron dolomite facies, unfossiliferous massive dark dolomite. Vugs near top contain secondary minerals, calcite, dolomite, sphalerite, and gypsum | 10-14'
Bertie formation (in pit in quarry floor) |
| Williamsville member: buff-weathering homogeneous waterlime with conchoidal fracture. A fine, even lamination determines breakage into thin plates. Upper surface makes quarry floor | 5'
| Scajaquada member: medium-bedded dark dolomitic limestone. Only upper portion exposed. | 15' &plusmn;

3C: MINERAL COLLECTING
Itinerary same as for Field Trip no. 1A (see p. 75) from U of R River Campus to Penfield Quarry of Dolomite Products Company (miles 0.0 to 10.3).
No road log

NYSGA 1957
New York State Geological Association
Twenty-Ninth Annual Meeting
Wellsville, N.Y. - May 9 - 12, 1957
Guidebook
for
Geology of S.W. Tier
Oil and Gas Fields
Oil Refining
Field Trips
Edited and Compiled
by
W. H. Young, Jr. and W. L. Kreidler

A: GEOLOGICAL OUTCROPS IN WELLSVILLE AREA
by W.L. Kreidler, N.Y.S. Geological Survey

A: GEOLOGICAL OUTCROPS IN WELLSVILLE AREA

Junction with Rte 19
Junction of Route 19, turn right (south). The Wellsville crops out at the base of the hills to the east which are capped by Germania or basal Cattaraugus.

STOP 1 Hinsdale Outcrop
9:07 A.M. Hinsdale outcrop in road cut along Fords Brook. This is a 20 minute stop. (Sta. 2 on Map 2)
Description:
Top - 7' | Hinsdale - interbedded gray micaceous siltstones 1" to 4" in thickness and gray shales; contain loose sponge spicules, Prismodictya sp. and Cyrtospirifer disjunctus.
Base - 5' | Wellsville - interbedded 1" to 4" dark purple siltstones and shales.

Outcrop to left, across creek

Oil Field
Oil wells in Fords Brook pool on left.

Tank Farm
Sinclair tank farm on left.
2010: Tank farm is gone...

Cross Genesee River
Cross Genesee River and turn left (north) at blinker light onto Route 19. (At northeast end of Genesee River bridge test hole encountered 125' of glacial deposits.)

Glacial and river terraces on right.

Terraces and Scio Oil Pool
Glacial and river terraces on left and Scio oil pool, on right, across railroad tracks. Top of producing sand is at a depth of 290'

Machias formation outcrops
Machias formation outcrops on right across Vandermark Creek.

STOP 2 Cuba and Machias outcrop.
10:00 A.M. This is a 45 minute stop. (Sta. 3 on Map 2).
Description:
Top - (the upper portion is accessible only with great difficulty and therefore the data for these upper units is taken directly from the Wellsville Bulletin)
Top - 20' | irregularly bedded buff sandstone
12' | fissile olive-gray argillaceous shale
13' | buff siltstone and sandstone containing numerous Tylothyris mesacostalis
2' | massive buff sandstone
5' | interbedded buff sandstone and siltstone
1.5' | massive buff sandstone (base of Cuba)
12' | interbedded gray shale and thin gray siltstone (top of Machias)
1' | fossiliferous gray siltstone
10' | mostly gray argillaceous shale with a few thin gray siltstones
1.5' | medium light gray siltstone containing coquinites of Cyrtospirifer disjunctus
6' | fissile medium gray shale with limonitic stain
2' | gray siltstone containing coquinites of Cyrtospirifer disjunctus
15' | mostly medium gray argillaceous shale showing limonitic stain, with a few interbedded 1" to 1' gray siltstone containing crinoid stems
road level - 20' | mostly medium gray shale with a few interbedded 1" to 2' gray siltstone
Base - 6' | interbedded medium gray shale and gray 1" to 2" siltstones (The lower two units are exposed in the creek bed below road level)

Madison Hill oil pool

STOP 3 Wellsville Outcrop in stream bed
11:02 Wellsville outcrop in stream bed about 100 yards north of street. This is a 45 minute stop (Sta. 1 on Map 2)
Description:
Top - 1' | medium light gray 2" to 4" siltstone
7' | olive gray shale with limonitic stain
12' | concealed
2' | medium light gray shaly siltstones and shales containing coquinites of crinoid stems; also present are Chonetes sp., Productella sp, and Cyrtospirifer disjunctus
2' | medium light gray 1" to 6" siltstone containing Cyrtospirifer disjunctus
4' | concealed
5' | interbedded olive gray shale and medium light gray thin to 2" siltstones; contain crinoid stems, Chonetes sp. and Cyrtospirifer disjunctus
3' | medium light gray 1" to 4" siltstones containing coquinites of crinoid stems and Cyrtospirifer disjunctus
15' | olive gray shale with a limonitic stain and only a very few interbedded thin gray siltstones
1' | gray fossiliferous coquinites of crinoid stems and Cyrtospirifer disjunctus
base - 5'
medium light gray thin to 3" siltstones containing flattened concretions ("storm rollers" ) up to 3' in diameter

Sinclair Refinery on left of road
2010: The refinery is no longer here, as it had a bad fire in 1958, the year after this field trip, and there was not enough oil left in the ground to justify rebuilding it. (It had also had a bad fire in 1936, but was then rebuilt.)

B: HARRISON VALLEY ORISKANY GAS STORAGE FIELD
by G. C. Borland, N.Y.St. Nat. Gas Corp

B: HARRISON VALLEY ORISKANY GAS STORAGE FIELD

Glacial terrace on left
Sand bank on left is in glacial terrace material.

On lake or stream terrace
On glacial lake or stream terrace on East side of Genesee valley. Stream cut in opposite side of river valley about 1 mile ahead and on right is old stream channel cut when glacial lake drained this way into the Allegheny River water shed. Present Mississippi River-Great Lakes watershed divide is about 1 mile up this valley West of Genesee River.

Sand and gravel quarry
Small gravel and sand quarry on right in glacial terrace material.

Out of main Genesee River Valley
Straight ahead and up hill out of main Genesee River Valley.

Gas pipe right-of-way
Cross cleared right-of-way of New York State Natural Gas Corporation's main transmission line from Sabinsville Field station to State Line Field Station. Right of way leads off to right at angle.

Drainage Divide
Left onto dirt. Hill top straight ahead is drainage divide between Great Lakes and Atlantic Coast water sheds. Elevation approximately 2200'.

Chemung Outcrops
Straight ahead. Chemung surface outcrop evidence. Catskill on scattered hill tops. Note slightly reddish color of stones in fence rubble and stone piles on these hill tops. These are predominately from sandy formations in the Catskill.( Cattaraugus).

Ida Scoville No. 1 Gas storage well
Gas storage well on right is the Ida Scoville #1 at northwest edge of Harrison Oriskany sand gas field. Oriskany is at 5201' depth.

Courtright storage well
Courtright storage well on left. Surface elevation 2225', top of Oriskany at 5129' in well.

Glacial material on left.
Glacial material on left. Terminal moraine of glaciers is about 10 miles south of this locale.

No. 2 Schofield storage well.

STOP 1 Harrison Compressor Station
New York State Natural Gas Corporation's Harrison Compressor Station, used solely for the storage of natural gas from Texas and the South in this previously depleted Oriskany sand gas field.
Plant Engineer's house and Schofield #3 storage well on left side of road. Park on right side of road next to fence. (see fig. 5).
ABSOLUTELY NO SMOKING INSIDE LIMITS OF FENCE.
11:30 A.M. The tour through the plant and "blowing off" the well will be completed about now. Those people leaving from this area can check their present location by looking at sketch in Chapt. VII, p.38.

C: SINCLAIR OIL REFINERY
Trip through the Sinclair Refining Company's Wellsville plant which processes Allegany crude oil.
No road log.
2010: The refinery is no longer here, as it had a bad fire in 1958, the year after this field trip, and there was not enough oil left in the ground to justify rebuilding it. (It had also had a bad fire in 1936, but was then rebuilt.)

D: OIL FIELDS AND WELL SHOOTING
by W. H. Young, Jr., Bradley Prod. Corp.

D: OIL FIELDS AND WELL SHOOTING

Descend from glacial terrace.
Incline is down off of old Genesee River glacial terrace.

Glacial lake terrace deposits.
Sand and gravel in left bank is at base of old glacial lake terrace deposits.

Pumping station in distance
Sinclair Refining Co. station in distance on right before crossing river pumps oil from Fords Brook field to Wellsville Refinery.

Shady Brook Glen of Fords Brook
Turn right and approach west edge of Genesee River flood plain, going through Shady Brook Glen of Fords Brook. 3" pipeline running along left side of road carries all oil from Fords Brook field to Sinclair refinery. Rocks in Glen are Hinsdale and Wellsville (see Stop 1, Trip A-1)

Oil wells
First few oil wells at extreme NE edge of Fords Brook field.

Gas pipelines
Cross cleared right of way (visible to left, up hill) of 14" and 20" diameter lines carrying gas from Pennsylvania and New York Oriskany gas fields to Rochester. Lines owned by New York State Natural Gas Corporation.

North edge of Fords Brook oil field.

STOP 1 Thornton Co. Warfield pressure plant.
1:50 P.M. STOP NO.1 Thornton Co. Warfield pressure plant. See water supply and injection wells, treating, mixing, filtering, pressuring and measuring of water and the filtering of oil wells for the water flood process of secondary recovery of oil.
ABSOLUTELY NO SMOKING OR OPEN FIRE PERMITTED while away from cars. (see fig. 6)

Injection well boxes
Boxes over water injection wells can be seen either side of road.

Injection wells
Turn left and proceed up very steep hill. On other side of hill road parallels a line of water injection wells (on right) with a different type of cover box.

STOP 2 Bradley Prod. Corp. Wesche property.
3:20 P.M. STOP NO. 2 Bradley Producing Corporation Wesche property. See pumping power, pumping and flowing oil wells, separator, stock tanks and gas saver used in oil recovery by water flooding.
ABSOLUTELY NO SMOKING OR OPEN FIRE PERMITTED in area of this stop. (see fig. 7)
4:30 P.M. Proceed on foot to see a well "shot" on the Bradley Producing Corporation Apco property about 1/4 mile east of STOP 2.

E: STRATIGRAPHY OF SOUTHWESTERN NEW YORK
by W. L. Kreidler, N.Y.S. Geol. Survey

E: STRATIGRAPHY OF SOUTHWESTERN NEW YORK

Leave Pleistocene deposits
Leave the thick Pleistocene deposits of the Genesee River Valley and continue on the Wellsville geological unit.

Station 9 Whitesville
Station 9. Slow down Whitesville (?) exposed in road cut, showing a storm roller zone, and a fine example of cyclic bedding.

Enter Allegany Oil field
On left (south), Sinclair Refining gathering tanks and pump station, entering the Allegany Oil field.

Allentown, N.Y
Allentown, N.Y., caution light near school. NOTE: Oil jacks in front yards and next to store.

Messer Oil Co. Lease
Messer Oil Co. Lease, with water treatment plant on right and power house on left.

Oil tank battery
Oil tank battery on right (north) side of Route #17.

Station 10 Whitesville fm
Slow down. Whitesville (?) exposed with fossils on road cut on right (north) side of road.

Whitesville fm.
Electric jack and Whitesville (?) on left (south) side of Route #17.

Pressure Plant on left

Siltstone outcrops
Siltstone outcropping alongside of road.

Western edge of Allegany Oil Field.

Water Plant on right

Glacial delta and river terraces
Cross over Dodge Creek bridge. Glacial delta and river terraces in the valley.

Dirty outwash material in glacial deposits
Entrance to Wolf Creek Scout Camp. NOTE: On left, stream or lake deposited dirty outwash material in the glacial deposits.

STOP 1 Wolf Creek flat pebbly conglomerates
9:26 A.M. (Station 11 on Map 2)
This is a 75 minute stop including loading and unloading.
Wolf Creek flat pebbly conglomerates in abandoned quarry on hill to right. The type locality of Wolf Creek conglomerate is at Sta. 12, 2.5 miles to the north and on left side of road. The Wolf Creek conglomerates are characterized by flat or discoidal quartz pebbles accompanied by occasional red jasper pebbles.
This quarry was opened about 10 years ago for rip rap to be used for levee dikes along the Allegheny River at Portville N.Y.
Top - 3' | olive gray micaceous siltstone
4' | massive sandstone with a little conglomerate, generally white with some limonitic stain; fossiliferous
3' | white 2" to 6" sandstone; fossiliferous
12' | massive sandstone and conglomerate containing "0rthoceras" sp., generally white with slight limonitic stain
Base -7' | massive white sandstone with a little conglomerate, showing slight limonitic stain
NOTE: From quarry you can see a glacial moraine dam and post glacial stream running from Scout Camp Lake through moraine on west side of valley.

Flood control dike
Flood control dike along Allegheny River on left (south) of Route #17.

Possible delta
To the right, pit in deltaic sands and silts. It might possibly be delta of Haskell Creek into Allegheny River valley during a glacial lake stage.

Olean Tile Company

Cemetery on glacial hill

Bradford Oil Field
Entering northern extension of Bradford Oil Field into New York State. NOTE: Boulders of Olean cgl along both sides of road.

Oswayo outcrop on left (east) side of road.

STOP 2 Cattaraugus red beds
11:24 A.M. STOP NO.2 Cattaraugus red beds with Oswayo above.
This is a 20 minute stop. (sta. 15 on Map 2)
Description: The Oswayo is composed of greenish-gray sandy shales with interbedded shaly, frequently fossiliferous, sandstone layers. The contact of the Cattaraugus and base of Oswayo is believed to be at the top of the highest red shale found in this section which is overlain by a fine-grained, greenish-gray, sandstone. Cattaraugus. A succession of red shales interbedded with greenish grey shales and fine-grained, greenish-gray, thin-bedded micaceous and argillaceous sandstones. It contains several well defined flat pebble conglomerate horizons. The Cattaraugus contains excellent cross-bedding and shows shaling out of the sandstones.

Row of crude oil stock tanks on left of dirt road.

STOP 3 Rock City Park
12:03 P.M. STOP NO.3 Rock City Park - type locality of Olean conglomerate.
NOTE: We will be here 2 hours, have lunch, examine outcrop and leave at 2:00 P.M. Mr. Melborne Cunningham, concessionaire at Rock City Park has made available to us picnic and parking areas. While here, the group will visit the type locality of the Olean conglomerate. (Sta. 16 on Map 2)
Description: The Olean conglomerate type locality is south of Olean, N. Y. at Rock City where it is 64' thick. There is an occasional layer of coarse quartz sandstone present in the conglomerate. Cross-bedding, joint cracks and large rounded or ellipsoidal pebbles are prominent features of the Olean conglomerate. The greater majority of the pebbles are vein quartz and milky in color but a few rose-colored ones are present. Pebbles 30 millimeters long are common, but most range from 10 to 20 millimeters in length.. There are a few pebbles of dark gray slate in the conglomerate. The Olean loses its conglomerate character as it is traced south into Pennsylvania. Fifteen to 20 miles south of the New York-Pennsylvania line it consists of a medium to coarse-grained quartz sandstone. The Olean conglomerate is found as far east as Alma Hill in Allegany County.
From hill is a good view of Olean and the former Socony-Vacuum Refining stock tank farm.

NYSGA 1958
FIELD GUIDE BOOK
New York State Geological Association
30th Annual Meeting
HOST
Department of Geology
The City College
New York 31, N.Y.
Prepared
by
Authors of the Several Chapters
and
J. Kaikow, H. Muskatt, E. Votava
Edited and Compiled
Kurt E. Lowe

1: PALEOZOIC INLIER OF THE PEEKSKILL VALLEY
S. Schaffel
The City College
Trip 1-A, 1-B and 1-E

1: PALEOZOIC INLIER OF THE PEEKSKILL VALLEY

STOP 1. Poughquag quartzite
Walk right (N) on Highlands Ave. and right (E) on approach road to Bear Mt. Pkwy. (approx. 500 ft.). Outcrop of Poughquag quartzite (Cambro-Ordovician) in unconformable contact with Highlands gneiss (Pre-Cambrian). Dips of bedding and foliation are nearly vertical. This relation is considered typical of that between Paleozoic sediments and Pre-Cambrian crystallines along the south side of the Peekskill inlier.

STOP 2. Annsville phyllite
Southwest extension of Gallows Hill underlain by Annsville phyllite (Cambro-Ordovician Hudson River pelite group) and mantled by Pleistocene delta deposits. Interesting consolidation and solifluction structures have been collected at base of hill. Walk through US 9 roadcut following left (W) side of cut only. Take care to stay on the roadway. Observe prominent slaty cleavage (axial plane type), diagonal shear planes, flow folding of quartzite bands and later quartz veins.

STOP 3. Wappinger limestone
Wappinger limestone (Cambro-Ordovician) outcrops on north side of west abutment of bridge. Observe gradational contact with Annsville phyllite outcropping along steep west bank of creek. Specimens from this transition zone are identical with those from the Wappinger limestone outcrop at stop 4.

STOP 4. Critical Outcrops
Outcrops along left (W) side of road, Cambro-Ordovician sequence exposed from S to N (dipping east) Annsville phyllite (approx. 100 ft.) Wappinger limestone (10 - 15 ft. ) is dark gray, fine-granular transition facies (same as in contact zone at Stop 3) Poughquag quartzite, coarse granular (only a few inches exposed), In contact with granite pegmatite (Highlands crystallines). Is this an intrusive or unconformable contact? Pre-Cambrian Highlands gneisses outcrop intermittently from this point northward. Berkey (1919), on his geologic map of the West Point quadrangle (1) shows the northern border fault of the Peekskill inlier passing between the Annsville phyllite and the Poughquag quartzite at this point; (2) fails to indicate the presence of Wappinger limestone; (3) indicates an unconformable contact between Poughquag quartzite and the Highlands crystallines. This critical exposure does not yield clear evidence of faulting either within the sediments or between them and the crystallines. An orderly sequence of Cambro-Ordovician sediments appears to be present here lending support to the concept of the synclinal structure of the inlier (Plate 2). The much reduced thicknesses of the Poughquag and Wappinger support the interpretation of Bucher (1957) (Plate 2. Fig. B).

STOP 5. Annsville phyllite and Highlands gneiss
South side of roadcut shows Annsville phyllite and Highlands gneiss with intervening limestone flow breccia (relations are somewhat obscured by grading): Breccia appears to be tectonic and represents the continuation of highly deformed and metamorphosed marbles along Canopus Creek (to NE) called Grenville by Berkey (1919). Its stratigraphic position, however, makes its correlation with the Wappinger limestone a likely alternative. In that case, the Canopus Creek carbonate belt may be infolded and infaulted Cambro-Ordovician rather than Pre-Cambrian marble.

2: NEW YORK CITY SERIES
K. E. Lowe and S. Schaffel
The City College
Trip 2-B and 2-E

2: NEW YORK CITY SERIES

STOP 1. Fordham gneiss
Quarry behind transformer station at left (N), now used by N.Y. State for gravel and road machinery storage. Typical Fordham gneiss, the oldest formation of the New York City series.

STOP 2. New York City series
The 3 formations of the New York City series outcrop in close proximity, although actual contacts are not exposed.
Manhattan schist (garnetiferous muscovite schist) NW of the intersection along a side road;
Inwood marble (medium grained, crystalline marble, here containing accessory graphite) in road cut on both sides of Granite House Rd.
Fordham gneiss (banded biotite gneiss) a short distance SE along cut-and-cover portion of Catskill Aqueduct. Formations appear conformable with nearly vertical dips. These rocks were traced continuously from the New York City line to this locality by Fluhr (1940). The thickness of the Inwood marble here is much reduced compared with that prevailing in New York City (approx. 750 ft.), a feature which is rather common in Westchester County. It has been explained by "squeezing-out" of the highly plastic rock and by faulting.

Manhattan schist
Manhattan schist exposures for the next 3 miles.

View of Palisades
View of Palisades across the Hudson River (below crest of hill)

Palisades and Hudson Highlands
Next 0.4 miles: Good view of strongly dissected Palisades to west and Hudson Highlands escarpment to northwest

Delta and moraine
Cross Croton River; Croton Point delta and moraine at left (W)

Deltaic deposits
Croton Pt. Ave. (entrance to Croton Pt. Park) left (W); deltaic deposits at right (E).

Palisades and Hudson Highlands

Gravel pit
Remnants of a worked-out gravel and sand pit (part of Croton Point glacial delta)

Manhattan schist
Exposures of Manhattan schist along road

View of Hudson River Gorge
View of southeastern gateway of the Hudson River gorge straight ahead (N)

Cortlandt complex
Exposure of Cortlandt complex hornblende norite with spheroidal weathering having passed over contact between Cortlandt intrusive complex and the Manhattan schist a short distance back (not exposed)

Exposures of Cortlandt complex hornblende norite at right (N)

Exposure of Cortlandt complex pyroxenite at left (S)

Inwood / Manhattan contact
At left (SW) (in front of school) contact between Inwood marble and Manhattan schist

STOP 3. Verplanck Point Quarry
STOP No. 2-3: Verplanck Point Quarry (N. Y. Trap Rock Corp. )
Approach to quarry is down the flank of a large mound of tailings deeply carved by erosion into typical badland topography. Pass several large glacial erratics below (Highlands crystallines).
DO NOT walk too close to the edge of the quarry which has not been in operation for some years.
In east face of quarry (looking north) is well-exposed contact between Manhattan schist above and Inwood marble below showing interbedding. Dips are steeply to the east (into quarry face). The Inwood marble, except for its rather fine texture, appears to be typical. In the schist, biotite predominates over muscovite and the texture is fine-grained and more gneissic than schistose. The variation from the typical lithology of the Manhattan schist in New York City is attributed to the influence of the Cortlandt intrusive pluton.
Depending on the water level in the quarry (the water is approx. 150 ft. deep) evidence of isoclinal folding of the marble can be seen in the north face of the quarry.
Collapse of the top of the east quarry face recently exposed a discontinuous zone of coarse Inwood marble breccia in a greenish to reddish crystalline matrix, close to the contact with the Manhattan schist. Mr. S. Schaffel who first observed this curious rock believes that it is of tectonic origin and that the matrix was affected by gaseous or hydrothermal solutions from the Cortlandt intrusive. Angular fragments of marble appear to be quite fresh and unaltered. Detailed microscopic examination of this rock (unreported from any other Inwood marble locality) will be undertaken in the near future. This interpretation then assumes at least post-Taconic age for the Cortlandt intrusive (see discussion of age relations of the New York City series).
1.5 miles to the southwest across the Hudson River can be seen the Tomkins Cove quarry (N. Y. Trap Rock Corp. ) in Wappinger limestone (Cambro-Ordovician). As discussed under age relations of the New York City series in the preceding pages, several attempts have been made to correlate this series with the Cambro-Ordovician rocks of the Hudson valley. At this locality the Wappinger limestone and Annsville phyllite (Cambro-Ordovician) are in rather close proximity to the Inwood marble and Manhattan schist (uncertain age), with only the width of the Hudson River intervening. This feature makes the correlation of these two rock sequences a tempting possibility. Let us then review briefly the several alternative lines of reasoning:
(1) The Verplanck Point rocks could be the metamorphic equivalent of the Tomkins Cove sediments on the basis of similar composition, stratigraphy and structure. Paige (1956) suggested an anticlinal arch across the Hudson River along which the progressive kinetic metamorphism took place in an easterly direction. The same author also indicated that contact metamorphism associated with the Cortlandt intrusion could account, at least in part, for the metamorphosed nature of the rocks at Verplanck Point.
(2) The authors cannot agree with this interpretation. Contact metamorphism would require an unusually broad contact zone around the margins of the intrusive, a feature which does not seem to be present in other localities at similar distances from the intrusive contact. Also the characteristic contact emery deposits in the mica schist seem to be absent here.
Progressive metamorphism could offer a plausible explanation were it not for the remarkably short distance in which a typical phyllite is supposed to have changed to a biotite-muscovite schist. One way out of this dilemma would be the assumption of westward thrusting (under the Hudson River) to account for the present proximity of the two contrasting metamorphic terranes.
(3) Verplanck Point rocks of the New York City series could be older than the Cambro-Ordovician sediments at Tomkins Cove. In that case the two rock groups must be in unconformable contact with each other beneath the river.
It becomes evident that the clue to this problem of correlation is buried under the Hudson River whose bedrock profile and structure are not known in this locality.
Note a typical kame ridge (in cross-section) on top of the north quarry face.

STOP 4. Inwood / Manhattan contact
Contact between Inwood marble and Manhattan schist on right (S) side of road. Note bands of small cubic pyrite crystals in the marble (influence of the Cortlandt intrusive).

Manhattan schist exposures along road

Cortland complex
Start of massive, glaciated exposures of Cortlandt complex augite norite at right

Cortlandt complex exposures
Intermittent exposures of Cortlandt complex augite norite for the next 1.5 miles

Last exposures of Cortlandt complex rocks (augite norite)

3: THE CORTLANDT COMPLEX
A. Dolgoff
N.Y. City Department of Public Works
Trips 3-A, 3-B and 3E.

3: THE CORTLANDT COMPLEX

View SE gateway of Hudson Gorge
Pause: View of southeastern gateway of the Hudson gorge - on west side of River (from left to right): Dunderberg, West Mtn. and Bear Mtn. (with tower).

Hill at right with outcrops of Cortlandt complex augite norite

Norite outcrops along both sides of road

STOP 1. Olivine pyroxenite
Olivine pyroxenite near northwest margin of "Eastern Funnel" (E on Plates 4 to 8) and "Olivine Region" (Plate 6). Typical spheroidal weathering similar to that of olivine zone in the Palisades. Dickerson Hill (center of "funnel") to the southeast. Banding mapped by Balk (Plate 5) is difficult to distinguish in this exposure. Discussion of structural and petrologic features of the Cortlandt complex.

Pyroxenite
Next 0.4 miles: Outcrops of pyroxenite at right (E)
The outcrops are either on the left (E) or on the right (W).

STOP 2. Old quarry dumps
Old quarry dumps on both sides of road. Collect samples of Pyroxenite (with and without olivine) and augite norite. Note indistinct banding and quartz -pegmatite veins cutting pyroxenite and norite.

Cortlandt complex / Manhattan schist contact
Pause: Passing over contact of Cortlandt complex with Manhattan schist (country rock); schist outcrops on both sides of road.

Schist outcrops at right

STOP 3. Kingston Emery Quarry
Kingston Emery Quarry (operated by Colbate Emery Co. , Peekskill, N. Y. ) presently the only operating emery quarry in the Cortlandt complex. Note the following:
(1) In quarry, down near the working face, excellent rectangular jointing. Rocks are highly magnetic. South quarry wall shows crusts of quartz and calcite, and quartz veins in the pyroxenite.
{2} Walking up cut leading out of main excavation observe the pyroxenite grading into more banded augen schist which becomes a normal schist at the quarry entrance (Colabaugh Rd.). This zone of transition represents the Cortlandt complex - Manhattan Schist contact. The country rock shows evidence of having been mobilized by the Cortlandt pluton during intrusion. The contact effects are also well shown in the schist outcrops near the construction shacks. The quarry has only been in operation since 1942. The contact shown on Plates 4 to 8 is not quite accurate and should be shifted southwestward close to Colabaugh Pond Road.
(3) Emery ore (samples on dump at quarry entrance) is dark blue-gray with an occasional pinkish hue and massive. Quarrying operation has followed ore vein down-dip.

STOP 4. Hornblende norite
Hornblende norite with poikilitic hornblende near western margin of central "basin" (C of Plates 4 to 8). Platy structure of hornblende crystals can be observed.

Poughquag quartzite
Pause: Poughquag quartzite (Cambro-Ordovician) in unconformable contact with Highlands gneisses (Pre-Cambrian) at right (S). Dips are nearly vertical.

4: PLEISTOCENE GEOLOGY OF CROTON POINT
Cecil H. Kindle
Trips 4-B and 4E.

4: PLEISTOCENE GEOLOGY OF CROTON POINT

Former Croton River delta
If one had chanced to come along route NY-129, one would have observed the gravel and silt deposits of the former Croton River delta on the left (S) just before reaching US-9.

Former delta surface
Continuing along US-9 we rise up onto this former delta surface and find a traffic light ahead. Let us turn right (S) here on Croton Pt. Ave. and proceed to the Harmon railroad station (Fig. 1) Here we notice the wide cut made for the railroad and its shops.

Croton Point
We do not stop now, but continue, observing a former tidal swamp, now filled with rubbish, on our left. Soon the delta remnant is behind us and we travel on a tombolo (bathing beach on our right and former swamp on our left) to the outer portion of Croton Point. We proceed to the large parking field at its southern end.
Ahead of us we see a sand pit which furnishes the material used to cover the rubbish in the former swamp. Let us examine this exposure. Here we find another remnant of the old Croton delta with sand and fine gravel resting on varved silty clay. Occasional concretions may be seen in the latter. Some of the silty clay layers are disturbed with horizontal layers above them. Are they the result of slumping or disturbance by floating ice?
Let us now walk S along the shore. We see numerous bricks, castoffs from the days when bricks were manufactured here. Behind some swimming rafts parked above the reach of the tide we see a cattail (freshwater) swamp which marks the source of clay used in brick manufacture.
As we proceed beyond the swamp we see delta sands, and 100 yards or so further we observe these varved clays resting on glacial till containing boulders of various sizes in a reddish matrix. Now we realize the source of the boulders among which we have been threading our way along the beach. The surface of this moraine is uneven and appears to be dropping below sea level for a distance before rising to 40 or 50 feet above sea level at Teller's Point (Fig. 1). A boulder bar extending south of Teller's Point marks its further continuation.
As we return to our cars we realize the preservation of the outer remnant of the Croton delta from wave erosion must be credited to this moraine.
We can now drive to the north end of the parking area and examine the north tip of the outer part of Croton Point. The weather and the state of the tide will determine whether we walk along the outer side of the point (more boulders) or the inner side (shorter). Woodchuck holes indicate that the top of the southern end of this point is deltaic sand. At the north end are glacial till and Indian shell beds. Erosion appears to be rapid at all points along the shore. Waves have certainly cut down the size of the Indian campsite (at the point) considerably since the oyster beds were laid there. Was sea level lower a short time ago? Does the (now buried) tidal swamp south of the tombolo indicate that sea level was lower when that portion of the old delta was eroded?
Return to cars and drive back to headquarters following the same route as taken at the start of the trip. Compare route description of Trip 2-B between mileages 20.9. to 25.8 and 30.6 to 36.4.

C: THE GEOLOGY OF THE TRIASSIC LOWLAND OF SOUTHEASTERN NEW YORK AND NORTHERN NEW JERSEY.
George F. Adams
Trip C

C: THE GEOLOGY OF THE TRIASSIC LOWLAND OF SOUTHEASTERN NEW YORK AND NORTHERN NEW JERSEY.

Annsville phyllite
Roadcut through Gallows Hill; Annsville phyllite (Cambro-Ordovician) Hudson River pelite group; see Trip 1, Stop 1- 2).

Glacial deltas
Note remnants of glacial deltas along both valley walls

Climb Highlands escarpment
Road starts climbing Highlands escarpment (fault line scarp); continuous exposures of Highlands crystallines (Pre-Cambrian gneisses, schists and granites) from here to Bear Mt. Bridge.

STOP 1. Anthony's Nose
Anthony's Nose lookout point. The Hudson River has cut a gorge through the Pre-Cambrian crystallines below the Schooley peneplane level, here shown by the hilltops. The rock bench on which the Bear Mt. Inn is located is interpreted as a remnant of the Harrisburg peneplane level formed by the Hudson River when it meandered at this level. Since Harrisburg time uplift permitted the stream to cut to lower levels before the valley floor was drowned. Glacial modification of the valley is indicated by its fiord-like walls and the shortcut east of Iona Island. The crystallines form an upthrown block of the fault associated with the Triassic Lowland to the south. See description of Trip D, Stop 1.

Views from bridge
Excellent views crossing bridge:
Left (S): lona Island and southeastern gateway of Hudson gorge; prominent notch at Timp Pass (SW) where major thrust fault crosses Dunderberg-West Mtn. ridge crest
Ahead (W): North side of bridge: Mouth of Popolopen Creek (drowned); Hell Hole fault notch between Bear Mtn. (left) and The Torne (right); Crown Ridge extending northeastward from The Torne; all these owe their topographic prominence to the Storm King granite
Right (N): Southern portion of the Hudson gorge; Sugarloaf Hill on east shore (3 mi.) (Canada Hill granite phase); Livingstone Island (east shore, 1 mi.) and Cons Hook (west shore, 2 mi. ) are separated from the shore by abandoned channels of the Hudson; bedrock terraces, particularly prominent on west shore.

River channel
Iona Island and abandoned river channel at left (E); Doodletown Brook (subsequent stream on Timp Pass-Hudson River thrust fault) at right (W); fault crosses road at this point

White, graphitic marble (Greenville?) at right (W)

View of Hudson gorge and gateway to left (N)

Hudson River Reserve Fleet
Hudson River Reserve Fleet (ship "graveyard" of World War II) at left (E)
There were probably over 130 ships here at the time of the field trip. All were gone by 1972.

View of Verplanck Point quarry
Verplanck Point quarry (Pre-Cambrian or -early Paleozoic Inwoodmarble) across River at left (E).
2010: Also of possible interest, the nuclear reactors Indian Point #1 and #2 are just to the north of the quarry.

Tomkins Cove quarry
Tomkins Cove quarry (Cambro-Ordovician Wappinger limestone) at left (E)

Wappinger limestone outcrop at left (E)

Triassic redbeds
Cross bridge over Cedar Pond Creek; Triassic redbeds along both walls of gorge below

High Tor
Haverstraw railroad station at left (E), Palisades (High Tor) at right (W)

STOP 2. Haverstraw Quarry
level with crusher and loader at right (pick up Company guides)
Haverstraw Quarry of the N. Y. Trap Rock Corp.
Buses follow quarry road to left and take middle road (SE) at fork of roads; gentle uphill grade
Lower Quarry Level (appr. elevation 238 ft. ):
The quarry, extending in a NW - SE direction, is in the intrusive diabase forming the northern arc of the Palisades. Here the strike of the diabase body is oblique to the strike of the Triassic sediments to the southwest indicating a cross-cutting relationship of the tabular igneous mass.
The prominent columnar structure of the diabase changes in attitude from nearly vertical (in the northeast quarry face) to easterly dips of 450 to 500 (in the northwest and southeast quarry face s). This feature suggests a rather abrupt change in the attitude of the intrusion with respect to the country rock from a gently dipping (150 SW) sill-like body to a steeply dipping (450 SW) dike. Preliminary results of recent extensive diamond core drilling on the Company's property bear out this contention (Fig. 2). It is not yet known whether the sill-like portion (Upper quarry level and Little Tor) is a true sill or a low-angle dike transgressing across the equally gently dipping Triassic sediments. The true thickness of the diabase intrusion appears to be approx. 700 ft.
Farther south the upper contact of the steeply dipping diabase dike can be seen cross -cutting the Triassic sediments at the portal of the West Shore Railroad tunnel (mileage 22.7). No stop will be made at this locality.
Also observe occasional oblique shear planes with narrow zones of brecciation in the northeast quarry face. return (NW) to crusher level sharp right (SE) turn on road leading to upper quarry level; steep grade
Upper Quarry Level (appr. elevation 340 ft. ):
On a clear day, a fine view of the Triassic Lowland shows the low sandstone ridges striking toward the observer and oblique to the diabase dike. The ridge line at the back of the quarry extends southward for several miles showing the mature dissection characteristic of the Schooley peneplane remnants. In the far distance (S) the even summit area of the Palisades is characteristic of the early mature dissection of the Fall Zone peneplane remnants. Sparkill Gap near the boundary of the two surface s is hidden from view. The headwater s of the Hackensack River have been impounded to form the Lake DeForest reservoir seen directly south. Turning toward the impressive northeast quarry face, observe extensive mass wasting aided by the near-vertical columnar structure and joint (.shear) planes dipping toward the quarry floor. A 50 ft. wide bench at approx. 430 ft. elevation, indicating the earliest quarry level, has been almost buried under weathered debris. This represents one of the hazards of quarry operation, overcome in part by leaving ever wider benches on successively lower levels (thus reducing the rock volume that can be quarried).
Return (NW) to crusher level
2010: Quarry operations over more than fifty years have modified this stop considerably. This path will correspond to the road log after leaving the quarry.

Columnar jointing
Unusually well-developed, polygonal columnar structure at left (SE)

Upper contact of dike
Passing over West Shore Railroad tunnel; portal at right (S) below road shows steep upper contact of diabase dike cross-cutting the Triassic sediments.

Roadcut through Palisades diabase

Triassic Redbeds
Triassic redbeds (arkose of the Stockton formation) dipping gently NW (into cliff) at right (W) (behind bottling plant); top of outcrop approx. 150 ft. above sea level; Tappan Zee at left (E).

STOP 3. Sparkill Gap
Note: Take your belongings, because the party will not return to buses until after lunch (approx. 1.5 hrs.)
As the Gap is approached from the north along the Hudson River several outcrops of the Stockton formation (mileage 30.9) extend up the valley wall to about 150 ft. above sea level. The contact with the diabase is not visible at these localities, but must be above 150 ft. elevation.
Walk across bridge into Tallman Mt. Section of the Palisades Interstate Park. Follow shore road southward. Here the diabase is first seen extending to sea level. Although the contact is not exposed at this point, its position can be estimated from the location of the olivine zone about 30 ft. above sea level. Elsewhere this zone is known to lie about the same distance above visible contacts. It is interpreted as the result of magmatic differentiation by gravitative settling of early olivine crystals in the still fluid diabase magma. The olivine concentration in the zone is up to 25%.
Continuing along the shoreline past the swimming pool, an outcrop of arkose holds up a low terrace a few feet above sea level. A ledge at the back of the terrace is indurated arkose near the igneous contact, which is not exposed. The higher slopes expose fine -grained diabase and farther up the olivine zone.
Farther south, at a place not to be visited, the contact rises to over lOft. above sea level. It is evident, therefore, that there is a sag in the base of the sill at Sparkill Gap which may be associated with faulting. That a thickening of the diabase is not involved, is indicated by a distinct narrowing of the width of outcrop at the Gap. We now walk back up the automobile road to the level of the Gap floor (some 200 ft. above sea level). Here coarser diabase outcrops nearer the interior of the sill. We are close to the north side of the Gap which extends southward for about 2 miles before the slopes rise to the summit at 500 ft. elevation (see mileage 36.1 to 36.7). To the north, we look down on the water gap of the Sparkill. An offset of the diabase on the west side of the gap indicates that this creek follows a cross fault. It is the only stream cutting through the Palisades for its entire length from Haverstraw, N. Y. to Bayonne, N.J. On the other (N) side of the Sparkill the diabase slopes rise to rounded hills reaching heights of 700 ft. Care must be taken to distinguish between the actual water gap of the Sparkill and the interpreted earlier wind gap of broader dimensions and greater height (Plate 9, Fig. A).
Johnson (1931) interpreted the wind gap as a part of the former course of the Hudson River established as a superposed subsequent during the Schooley cycle. Later the river cut a water gap through the Palisades sill during the Harrisburg cycle. This water gap was abandoned when capture diverted the Hudson into its present course southward. At this time a reversal of drainage through the gap established the Sparkill as a tributary to the Hudson along the fault line mentioned above. (Plate 9, Fig. B).
Lunch in picnic grounds at north end of Tallman Mt. State Park return to buses via the same route

Fall Zone peneplane
Turn off road to right in front of large (burnt-out) road house Pause (if time permits): Discussion of Fall Zone peneplane level.

STOP 4. Flatrock Brook
The outcrop of diabase near the road is close to the upper contact of the Palisades sill. It is fine-grained and cut by thin acidic dikes. The hill-slope down toward the Brook approximates the dip-slope of the upper contact. The contact zone appears in the Brook as the diabase gives way to light-colored baked shales with low northwesterly dips. The actual line of contact is obscured by cover. Similar baked shales are found at the lower contact near Edgewater, N. J. but of much darker hue. The baked shales of the upper contact continue south along the strike of the sill. Their most impressive exposure is in Granton Quarry at North Bergen, N. J. where they underlie a subsidiary sill of diabase. Fossil fish (coelacanths) and a small crustacean (ostracod) have been collected from that locality. Both the lithology and fossil content of these beds strongly suggest the Locatong formation, although they occur many miles north of the main outcrop area of this formation.
Looking east from the road outcrop, one sees US-4 descending a valley which runs oblique to the upper contact in a northerly direction. The valley follows a fault line of the gravity type with downthrow on the east. The vertical displacement is approx. 100 ft. and appears to be related to adjustments connected with the emplacement of the magma.
Looking west, one sees the drowned valley of Overpeck Creek and beyond the low sandstone ridges of the Brunswick formation, approx.at the Harrisburg level. The skyline ridge is the First Watchung Mountain, a lava flow (fissure type) approximating the Schooley level. It should be possible to make out the Paterson wind gap which is similar in form and origin to the Sparkill Gap.

STOP 5. Brunswick Formation
Woodcliff Lake area - Brunswick Formation Construction of the Garden State Parkway below produced this new road and outcrop. These are rather typical sandy beds of the Brunswick formation. The shaley beds are usually found in the valleys. The brown sandstones here contain a few pebble beds which could be stream channel deposits. Conglomerate cobbles similar to those found near the border fault (Stop C-6) in alluvial fan deposits suggest a westerly source. This outcrop is about 8 miles from the border fault.

STOP 6. Triassic Border Fault
Park at right (on US-202): outcrop along road (uphill) at left (NW) The outcrop consists of badly sheared, Pre-Cambrian (granite) gneisses. Many slickensided surfaces are parallel to the surface of the border fault. The lineation (fault striae) approximates the direction of relative motion along the fault. While this is not considered to be the actual fault plane (dipping steeply southeast with downthrow of Triassic sediments to the south), it is probably within the fault zone. From a high point one sees the escarpment (Ramapo Mts. of the Hudson Highlands) extending beyond the Thruway toward the southwest. This escarpment is the product of differential erosion along the fault whose relative motion dropped the Triassic beds down on the southeast in contact with the Pre-Cambrian crystallines. The whole mass was deeply eroded by the time the Schooley peneplane was produced. The escarpment was developed later as a consequence of regional uplift. Looking southeastward toward the Triassic Lowland, a prominent hill just across the Thruway is an eroded plug-like intrusion of diabase (now being quarried for crushed rock).

Highway leaves fault line
US-202 swings away (S) from fault line proceeding on the rocks of the Triassic basin

STOP 7. Triassic Border Conglomerate
Y-intersection with Viola Rd. (Antrim Playhouse sign); park in triangular plot at right of US-202; outcrops on both sides of road These outcrops are about 1/4 mile east of fault line. Here the Mahwah River has etched a valley along the fault zone in Triassic beds. The outcrop at left (NW) side of road indicates former alluvial fan which was banked up against the original fault scarp. The presence of early Paleozoic cobbles, sometimes only slightly rounded, and the absence of the crystalline cobbles lead to several conclusions: (1) streams cutting into the upthrown block were relatively short, (2) the upthrown block was much higher than at present and contained a thick Paleozoic cover, (3) as the streams cut into this cover they nowhere reached the Pre-Cambrian basement, and (4) the upper surface of the fan must have been higher than the present Schooley level. What we see now are a few remnants of this fan showing typical torrential cross-bedding and rapid changes in grain size. Cobbles consist of Cambrian quartzite, Cambro-Ordovician limestones and Silurian-Devonian conglomerates. None of these rocks are now present on top or within the Pre-Cambrian crystallines of the Hudson Highlands directly to the northwest. Some have been preserved, however, as inliers to the west (along the New York-New Jersey border and in the New Jersey Highlands). They also outcrop abundantly in the Great Valley beyond the present Highlands to the north and northwest. On the east (SE) side of the road, pebble beds decrease and a more normal Brunswick aspect appears, similar to that seen at Stop C -5.

Fine-grained diabase
Lime Kiln Rd. at right (S); fine-grained diabase; intrusions of diabase outcropping intermittently along south (right) side of road for the next 1.5 miles are presumed to be one or more plug-like bodies or dikes; rare contact exposures show cross-cutting relationships.

Coarse border conglomerate at right (S)

Coarse border conglomerate on both sides of road

Diabase with columns
Next 0.2 miles: fine-grained diabase with columnar structure at right (S)

STOP 8. Mt. Ivy Glacial Delta
Park at entrance of sand and gravel pit at left (N) side of road This appears to be a fairly normal delta deposited in a periglacial lake, with typical top and foreset beds. No varved clays are exposed. The elevation of the delta top is 400 + ft., which indicates that it was a local lake feature not connected with the Hudson River 4 miles to the east.

View of Palisades
View of Palisades ahead to right (E); westerly end of hook-shaped Palisades ridge (dike) rising from beneath Triassic sediments (Plate 13)

STOP 9. Triassic Fanglomerate
This remarkable remnant of another alluvial fan consists almost entirely of semi-rounded Wappinger limestone (Cambro-Ordovician) pebbles poorly cemented by calcite and hematite. The source formation can be seen in place along a road to the north (mileage 86.5) and has wide exposure in the Tomkins Cove quarry 0.5 mile to the north. The occurrence of the Cortlandt complex and some gneisses of dubious age at Stony Point to the east suggest some complicated step-faulting in the region.

Wappinger Limestone
Roadcut through folded Wappinger limestone (Cambro-Ordovician); this belt of limestone widens northward where it is quarried at Tomkins Cove (0.5 mile)

D: PRE-CAMBRIAN AND PALEOZOIC GEOLOGY OF THE HUDSON HIGHLANDS
Kurt E. Lowe
Trip D

D: PRE-CAMBRIAN AND PALEOZOIC GEOLOGY OF THE HUDSON HIGHLANDS

STOP 1. Anthony's Nose
Anthony's Nose Lookout (See Plates 10 and 11, Fig. B)
Lithology: Canada Hill phase of Highlands Complex (Canada Hill granite of Berkey, 1919) - biotite oligoclase granite with epidote pods; gneissoid structure not pronounced; interpreted as granitized meta-sediments
Hudson Gorge: Southeastern gateway of Hudson gorge; superposition versus progressive headward stream erosion of the Hudson River; Iona Island and abandoned River channel; significance of bedrock terrace at Bear Mt. Inn
Faulting: Timp Pass - Hudson River thrust fault; channel fault (?) at Dunderberg ML ; Hell Hole tear fault (Popolopen Creek)
Regional Structure and Intrusive Plutons: Synclinal plutons of Storm King granite: Dunderberg and West Mts. (lower pluton) Bear Mt. - The Torne and Crown Ridge (upper pluton)

Views crossing bridge
Excellent views crossing bridge:
Left (S): Iona Island and Southeastern gateway - prominent notch at Timp Pass, where fault crosses West Mt. - Dunderberg ridge
Ahead (W): South of bridge: Bear Mt. terrace North of bridge: Mouth of Popolopen Creek (drowned); Hell Hole fault notch between Bear Mt. (left) and The Torne (right)
Right (N): Hudson gorge (southern portion); Sugarloaf Hill on E-shore (3 mi. NE) (Canada Hill granite phase); abandoned river channels at Livingston Island (1 mi. on E shore) and Cons Hook (2 mi. on W shore); bedrock terraces, particularly on W-side of river

STOP 2. Bear Mt. Inn Terrace
Walk N along W-edge of playing field: glaciated and striated outcrops of pegmatitic Canada Hill granite phase (S of roller skating rink); outcrop of sillimanite-garnet-biotite gneiss and schist (metasediments of Highlands Complex) at SE corner of rink
Hessian Lake: Shallow, glacially scoured contact line depression in Grenville (?) metasediments (including marble bands); intrusive contact with Storm King granite pluton along Sand W shores of lake; Canada ~lill granite phase along NE shore (Plate 12).
Ancient landslides of large Storm, King granite blocks (SW shore) from near vertical cliffs (obscured by trees) developed along major NE trending longitudinal joints in granite; prominent exfoliation of Storm King granite along W -shore; steep W -shore profile developed parallel to linear and platy structure of hornblende crystals in Storm King granite

STOP 3. Storm King Granite Contact
This stop on SW flank of Bear Mt, will be reached on foot (.6 mi. from entrance), because buses are not permitted on the Perkins Drive. It is regrettable that the planned visit to the top of Bear Mt. had to be eliminated for the same reason.
Keep to the left side of the Drive facing traffic and watch for cars on this winding 2-lane, 2-way road.
Layered sequence of Highlands Complex rocks: Biotite and hornblende gneisses and schists with intercalated bands of pseudo-alaskite (Canada Hill granite phase); interpreted as the result of selective granitization of metasediments (micro-pegmatite bands parallel to structure; replacement of quartz by plagioclase feldspars and perthite in thin-section); biotite in places makes rock indistinguishable from Canada Hill granite of Berkey.
Lower contact of Storm King granite pluton: (at nose of syncline) with metasediments; xenoliths near contact; dark- green, chloritized, quartz-rich contact phase of Storm King granite 500 ft. NW along road; prominent exfoliation of massive granite; typical "rubbly" weathering along linear hornblende structure; if time permits: visit to eclogite locality 100 feet below on abandoned road; metamorphic pyroxene (diallage) - garnet - graphite - quartz layer in Highlands Complex; source rock questionable.
2010: Path shown assumes users will not be in buses.

Banded metasediments
Prominently banded metasediments (biotitic and graphitic gneisses and schists) at left along Palisades Parkway.

Brooks Hollow marble
Passing between Lake TeAta. (left -S) and Lake Massawippa (right -N); construction of dam (at N end of Lake Massawippa) across the Brooks Hollow Creek temporarily uncovered a striking coarse-grained marble (contact-metamorphosed by intrusive Storm King granite) consisting of pink calcite, pale-green diopside and brownish phlogopite (named the Brooks Hollow marble).

STOP 4. Popolopen Natural Bridge
Walk 0.25 mile to SW end of Popolopen Lake
Natural Bridge across creek flowing into Popolopen Lake, developed through coarse, white, chondrodite-bearing marble; spinel dike on down-stream (lake-side) of bridge; curious dense, dark gray rock paralleling marble and creek on upstream side; thin-section study suggests a metamorphosed graywacke; both rock types along creek are completely different from known Pre-Cambrian metasediments in the Hudson Highlands; preliminary reconnaissance also indicates strong deformation of Highlands rocks along both sides of Popolopen Lake valley; rocks at this locality are, therefore, interpreted as infolded (and possibly infaulted) Paleozoic sediments(inlier).

Top of Escarpment
Top of NE-trending fault-line escarpment of crystalline Hudson Highlands; view of Central Valley (belt of early Paleozoic limestones)

Brecciated zones
Brecciated zones in Highlands gneisses at right (only evidence of steeply SE dipping border thrust at base of escarpment)

Last outcrop of Highlands crystallines (Pre-Cambrian)

View of Schunemunk Mt.
Passing over N. Y. Thruway; view (straight ahead) of Schunemunk Mt. (Devonian orthoquartzite and conglomerate).

STOP 5. Devonian Sediments
Cross railroad tracks to prominent outcrops along E-side of right of way. Devonian shaly sandstones (Oriskany-Esopus-Schoharie horizons)
Fossils:
Lower strata: poorly preserved sponges of type Titusvillia (?)
Leptocoelia flabellites, Leptaena rhomboidalis and other brachiopods
Middle strata: Spirophyton caudagalli (worm burrows or algal swish marks? ? )
Upper strata: Cypdcardinia (pelecypod)
Brachiopods (several genera)
Phacops and Dalmanites (trilobites) (confined to a single layer, hard to find)
Time will not permit to traverse across hill to E; in valley E of hill can be found (in descending stratigraphic order) Lower Devonian and Upper Silurian limestone (with corals), Silurian red shales (Longwood) followed by Lower Silurian conglomerate (Shawangunk) in Pine Hill beyond. Between Pine Hill and the Highlands escarpment to the E are beds of Wappinger limestone (Cambro-Ordovician). The exact structural relations between these stratigraphic sequences are not known with certainty. Westward across the valley of Woodbury Creek the shaly sandstones of the Highland Mills station appear to include the Hamilton group and are finally overlain by (Upper ?) Devonian orthoquartzites and conglomerates of Schunemunk Mt. (a shallow syncline).
Approximately 1 mile to the north, along the E-side of the railroad, rocks of Oriskany lithology have been correlated with the Kanouse horizon (Onondaga) on good fossil evidence. (Eidman and Kindle. 1955)

Glacial delta deposits on both sides of narrow valley

STOP 6. Overthrust in Highlands Outlier
Walk S on Mountain road, crossing bridge to outcrop in hill at left (E) side of road (appr. 300 yds.)
Overthrust of Storm King granite (Pre-Cambrian) on intensely crumpled slaty shales of the Hudson River pelite group (Cambro-Ordovician).
Thrust plane dips rather gently toward the southeast. Small hill appears to be an outlier because Lower Paleozoic sediments have been found between it and the Highlands escarpment a short distance to the SE. Attitude of thrust plane here is atypical of Highlands border thrust which generally dips at high angles (70° in Delaware Aqueduct Tunnel E of Hudson River) to the SE.

STOP 7. Crow's Nest Lookout
View of middle Hudson gorge; West Point Military Academy on rock terrace below; Constitution Island with abandoned river channel; similar to Iona Island (Stop No. D-l), but on E-side of valley; Schooley Upland level E of the Hudson.

Large xenoliths
Large xenoliths of hornblende gneiss in pegmatite phase of Storm King granite at right (W)

Return
2010: Cross bridge and return by the same route taken to get here.

GEOLOGY OF THE CAYUGA LAKE BASIN
A Guide for the 31st Annual Field Meeting of the
New York State Geological Association
prepared by
Staff and students of the Department of Geology
Cornell University
"....We must especially collect and describe all the organic remains of our soil, if we ever want to speculate with the smallest degree of probability on the formation, respective age, and history of our earth."
Second (Revised) Edition
Ithaca, New York
May, 1959

A: ENFIELD GLEN (ROBERT H. TREMAN STATE PARK)
by Staff and Students
of
Cornell University

A: ENFIELD GLEN (ROBERT H. TREMAN STATE PARK)

Cross delta plain
Down the eastern wall of the Cayuga trough, and west across the delta-plain to Albany street, turning south.

Views of Coy Glen
Excellent views west from this stretch of road of the surface of the delta plain and the sequence of hanging deltas through which the Coy Glen stream has cut its gorge.

Railroad underpass
Just south of this underpass the end of the interglacial Buttermilk gorge may be seen on the east to be followed slightly to the south by the hanging valley waterfalls made by the post-glacial Buttermilk stream as it descends the oversteepened eastern wall of the Cayuga trough. The large gravel pit to the south of the Buttermilk falls was excavated in the hanging delta sequence made by Buttermilk creek.
The bed-rock exposed in Buttermilk Falls is the Ithaca formation. The upper member of the Ithaca shale begins at about the top of the first cascade.

Cross delta-plain
The road crosses the delta-plain to the west side of the valley and continues southward on glacial deposits

West wall of trough
From the floor of the Cayuga trough the road climbs the west wall. Small hanging deltas may be observed in several of which gravel pits have been opened.

Treman State Park
Upper or western entrance to Treman State Park. The parking area is in a post-glacial, excavated part of an interglacial gorge (see diagram for details). (The buses will leave the parties and later meet them at the lower or eastern entrance.) From the parking area, walk to the entrance of the post-glacial section of the gorge. This post-glacial gorge is nearly at right angles to the drift-filled interglacial gorge which swings around the rock island which forms the north wall of the post-glacial gorge. The outstanding feature of the post-glacial gorge itself is the perfection of joint-plane control of the stream course.

Lucifer Falls
Lucifer Falls at the eastern end of the upper gorge is slightly upstream from the main southern wall of the interglacial gorge which has been excavated by the post-glacial stream. The upper gorge is cut in the Enfield shale. The base of the Enfield formation is about at the top of Lucifer Falls. The lower sector of Enfield Glen is in the Ithaca formation.
Several sedimentary features are well developed in the rocks in the vicinity of Lucifer Falls, including current ripple marks that demonstrate that the general current direction was from northeast to southwest. Moreover, there is a submarine erosion channel which shows well in the south wall of the gorge above Lucifer Falls.
View eastward before descending into the interglacial part of the Enfield Glen the eastern, over steepened slope of the Cayuga trough.

Eastward from Lucifer Falls.
The trail follows down the drift-filled interglacial valley and thence along the excavated part of interglacial valley. Sulphur falls and the Lower falls represent spurs of the interglacial valley upon which the post-glacial stream was superimposed.

B: CAYUGA INLET TROUGH
by Staff and Students
of
Cornell University

B: CAYUGA INLET TROUGH

Downtown Ithaca
From Cornell campus descend into Cayuga trough to downtown Ithaca built on compound delta of four creeks. Valley fill more than 400 ft. thick. Bottomlands subject to flooding.

STOP 1. Buttermilk Falls.
Lower portion of Enfield and upper portion of Ithaca formation exposed. Representative of notched lower reaches of hanging valleys of Cayuga trough but contrasts with gorges initiated prior to last glaciation. Buttermilk Creek was diverted by glacial deposition in its interglacial gorge. Hanging deltas exposed in gravel pits 150 yards south.

STOP 2. Coy Glen hanging deltas.
Excavations by Rumsey Ithaca Corporation expose structure of massive deltas built into pro-glacial Lakes Warren and Dana during recession of the continental ice sheet in late Wisconsin time. Coy Creek in incising a meander initially developed across the main Dana delta has imposed on it second order meanders controlled by bedrock joints.

Kame and Kettle topography
Continue south on Route 13 over kame and kettle topography. Contrast steep southeast wall with gentler northwest wall of Cayuga trough.

Enfield Glen
Pass Enfield Glen and entrance to Robert H. Treman state Park

STOP 3. Shaffer Road overlook.
Meltwater from a pro-glacial lake briefly impounded near Newfield flowed through ice-walled channels, cutting the bench followed southeastward by Shaffer Road and debouching across kame terrace to the southeast. View across stagnant ice deposits which fill the southern end of Cayuga trough.

Kame complex
Descend into Cayuga trough over kame complex, via Piper St. to Stratton

Stagnant ice deposits
Turn right (south) on Route 34 at Stratton, riding across a complex of stagnant ice deposits which mark minor glacial oscillations during down-wasting of the Cayuga ice tongue in recession from the Valley Heads terminal moraine.

High point on road
Route 34 climbs to 1130 feet, about 750 feet above Cayuga Lake.
Tributaries to Cayuga trough have entry angles pointing north, whereas tributaries to the through valley south of this point have entry angles pointing south, suggesting that the present depositional divide between St. Lawrence and Susquehanna watersheds corresponds approximately with an interglacial or preglacial bedrock divide.

Enter outwash
Highway passes onto outwash where moraine ridge curves southeast.
Pitting and large kettle lakes (e.g. Spencer Lake) indicate outwash deposition onto unmelted stagnant ice. Valley Heads terminal moraine about 2.5 miles south of this point is largely buried in outwash.

Large kettle lake
Cross swampy edge of large kettle lake. Toward east side of Cayuga trough road curves north to parallel low, narrow ridge which separates it from south-flowing Michigan Creek.

STOP 4. Point. O'Rocks.
Ice and ice marginal deposits near the Valley Heads maximum crowded Michigan Creek against the side of its valley, forcing it to cut a bedrock channel around this point. During ice wastage Michigan Creek deposited a fan into which it is now cutting. Kame exposed in borrow pit.

Moraine
Moraine deposited by ice moving south down Michigan Hollow crosses valley.
Kames exposed in cuts and gravel pits to east near road. Valley bottom widens northward with swamp and ponds, the remnants of a small pro-glacial lake impounded behind the moraine until drained by Michigan creek.

Moraine ridge trending northeast across Danby Valley.

View of Portage escarpment
Road is here at 1500 feet above sea level on the glacially modified upland erosion surface. View northeast across Hungerford, Snyder and Turkey hills at the edge of the deeply dissected Portage escarpment.

Former ice-walled spillway
Descending the upper slope of Sixmile trough, cross rock bench at 33.6 miles.
This bench at 1030 ft. is continuous northwest to the abrupt nose on South Hill which marks a former ice-walled spillway.
Here the waters of pro-glacial West Danby Lake in Inlet trough first escaped eastward into Slaterville lake in Sixmile trough just before the two joined to form Lake Ithaca with outflow southeast past White Church and Willseyville.

C: AROUND CAYUGA LAKE
by Staff and Students
of

C: AROUND CAYUGA LAKE

Views of Cayuga trough
North towards Trumansburg (Views of Cayuga Lake trough to right. Note southerly dip of rocks on east shore of Lake; prominent datum plane is the Tully limestone).

Taughannock State Park.
East along upper Taughannock creek; exposures of middle part of Ithaca formation.

STOP 1. Main Falls Lookout.
Exposure of Geneseo, Sherburne, and Ithaca formations in gorge walls.

Delta and lower falls
Continue down hill to Rte. 89, south across Taughannock Creek and present delta, with view on right of lower falls over Tully limestone.

STOP 2. Hubbard Quarry.
Contact of Geneseo and Sherburne formations, Middle-Upper Devonian boundary. Fossils. Septarian concretions.

STOP 3. Fayette Town Quarry.
Upper Skaneateles (Levanna) shale in lower part of quarry; lower part of Centerfield member in upper part. Fossils from both members; septarian concretions.

STOP 4. Old Wolf Quarry (Warren Bros. Road Co.).
Upper Onondaga limestone (Seneca member). Tioga metabentonite.

STOP 5. Lunch Stop: Cayuga Lake State Park

STOP 6. Yawger's Woods.
Walk west from road 0.5 mile to woods, through woods to outcrop of Manlius (Olney) limestone and Oriskany sandstone.
Fossils from Oriskany (sledgehammers useful!).

STOP 7. Portland Point Quarry.
Upper Moscow (Windom) shale, Tully limestone, Lower Geneseo shale. Fossils. Alnoite dike. Low-angle thrust.

GUIDEBOOK FOR FIELD TRIPS
32th Annual Meeting
NEW YORK STATE GEOLOGICAL ASSOCIATION
prepared by
David Hawley and Donald B. Potter
HAMILTON COLLEGE
Clinton, New York

A: FRANKFORT GULPH SILURIAN SECTION
Purpose: The trip visits exposures of the Frankfort-Oneida disconformity, the overlying Clinton group, and the Vernon shale. These are the best exposures of the Clinton group in the type area.
Acknowledgments: The itinerary was suggested, and the localities described in Marshall Kay's "Geology of the Utica Quadrangle," 1953, New York State Museum Bulletin #347.
General: The unconformity at the base of the Oneida conglomerate is a reflection of the Taconian orogeny in New England. Most of the upper Ordovician and all of the lower Silurian are missing in this time gap. The overlying formations reflect a shoreline encroaching from west to east across New York State. The peculiar environment of deposition of the Clinton iron ores is discussed in section B of this guidebook. The Vernon shale, lowest member of the Salina group, represents the mud flats of a great delta built out from the east, which was intermittently encroached upon by hyper-saline seas from the west (Fisher, 1957). The extension of Seas eastward across the state during Silurian time accompanied the erosional reduction of the Taconian mountains in New England.

A: FRANKFORT GULPH SILURIAN SECTION

Bertie waterlime quarry
Abandoned quarry to right (S) of road, in Bertie waterlime. This is Crow Hill.

View of Mohawk Valley
Downhill into Sauquoit Valley. Mohawk Valley in distance to left (N).

Lake Herkimer delta foreset beds
Gravel pit on left (N) has coarse gravel foreset beds. It is a delta that was deposited in Lake Herkimer. Elevation of top is 1280'.

STOP 1. (the only stop on this trip) South Moyer Creek section.
Very sharp curve just beyond bridge over Moyer Creek. Park buses on right beyond curve and disembark.
KEEP WELL OVER TO OUTSIDE OF CURVE. EXAMINE THE FRANKFORT-ONEIDA CONTACT, AND MOVE ON SO OTHERS MAY DO SO.
This is one of the representative sections described by Kay (1953) as being the best, almost continuous exposure of the Silurian in the Utica quadrangle, and the following description is partly abstracted from his (p. 28-32).
At the bend of the road at the junction of Moyer and South Moyer Creeks, the road cut exposes the Sauquoit sandstone over the Oneida conglomerate, which in turn lies unconformably on the Frankfort shale (Moyer member). The Oneida is a massive quartz-pebble conglomerate which in the lower part contains many fragments of the underlying Frankfort. The basal 4-6 inches is impregnated with pyrite. The Oneida-Sauquoit contact is not accessible here, and is not sharply defined. It is inferred to be just below the strongly cross-bedded sandstone about 20 feet above the base of the Oneida.
About two hundred feet up the road, descend the bank on a trail, cross Moyer Creek, and proceed up the valley of South Moyer Creek.
Several hundred yards upstream the creek flows in a narrow channel cut in clayey till.
Upstream from the channel-cut till is the first Sauquoit sandstone, pebbly, dark greenish-gray heavy ledges. About fifty yards farther are the ripple-marked, coarsely (3') cross-bedded ledges figured by Kay (1953, p. 34). Worm trails 1n the sandstone str1kingly resemble recent trails on bottom sand, often found here.
Farther upstream, 100' above the Sauquoit base, is a 20-foot zone of hematitic sandstone with red and greenish-gray clay galls and prominent cross-bedding (Grossman, in Kay, 1953, p. 68).
Still in the Sauquoit are beds of green shale interbedded with fine-grained sandstone. Interference ripples show well on several beds. These beds are somewhat fossiliferous.
Farther upstream on a l2-l8-inch fine conglomerate bed are giant current ripples (WL about 30"), and above that a sandstone bed with prominent smaller current ripples. Current modified interference ripples appear on ledges about fifty yards farther upstream.
In the upper Sauquoit are heavy ledges of hematitic sandstone.
Above this the contact with the overlying Willowvale, and its basal oolitic hematite bed, is covered. The Willowvale is green, thin-bedded shale with some interbeds of fine-grained sandstone and siltstone, 30 feet thick.
The base of the overlying Herkimer is marked by a prominent 1-2 foot bed of strongly cross-bedded, sandy, oolitic hematite, which in other localities is as much as 3 feet thick (Kay, 1953, p. 35. fig. 25). The Herkimer is 80 feet thick, of interbedded rusty-weathering, pyritiferous, sandy dolomite and dolomitic sandstone, and gray shale. Several cascades are formed by resistant beds in the Herkimer.
The top of the Herkimer is distinct, though the contact with the overlying Ilion Shale (Fisher, 1960) is covered. Within a few feet of cover there is a change from the dolomitic sandstone of the Herkimer, below, to dark gray, fissile shale with 2-4 inch dolomite beds. The Ilion (Lockport?) is shown in fig. 24, p. 35 of Kay. It is 55 feet thick here.
The overlying Vernon has at its base 5 feet or more of green shale which is noticeable lowest in the stream channel. Above the basal green shale zone, which contains a few dolomite concretionary beds, is the typical red, crumbly, practically unbedded mudstone. The Vernon continues to the top of the exposed section in South Moyer Creek.
Board the waiting buses and return to the Hamilton Campus

B. CLINTON METALLIC PAINT COMPANY MINE
Clinton Metallic Paint Company Mine, Brimfield Street, Clinton, N.Y.
Proceed to mine by your own transportation. Small groups will be taken underground at regular intervals between 1:30 P.M. and 4:15 P.M.
Owner: Mr. Bruce M. Bare
Mine Foreman: Mr. Robert Barry
In charge of Mine Trip: Mr. Alvin J. Snyder
EVERYONE VISITING THIS MINE MUST SIGN A WAIVER AND GIVE IT TO MR. SNYDER BEFORE GOING UNDERGROUND. PLEASE SHOW DUE RESPECT FOR ALL PROPERTY AT THIS TIME.
This mine closed in 1963.

Clinton Metallic Paint Company Mine
The mining of oolitic hematite at Clinton, N.Y. dates back to 1797. Up until the first World War ore was used as a source of iron and the smelting was done locally at Franklin Springs and Kirkland. The Clinton Metallic Paint Company sank its Brimfield Street shaft in 1928. The mining is a modified longwall operation; the ore is hand sorted at the working face and again at the mine head. At the company's plant in Franklin Springs the ore is crushed to pass 325 mesh, bagged, and sold as a paint pigment, coloring agent for cements, and as a casting powder. There are two principal beds of oolitic hematite in the Clinton Group (see details below and general stratigraphic position in the Table of Silurian Formations, Trip A) The Westmoreland ore is the bed mined at Brimfield Street. Alling (1947) shows that the Westmoreland ore at Clinton, N.Y. consists of a lower one-foot layer of oolitic hematite separated by two feet of "siliceous" rock from an overlying two-foot layer of oolitic hematite. At the Brimfield Street mine this intervening "siliceous rock" or shale parting is generally absent so that the Westmoreland ore bed is about 30 to 36 inches thick and quite homogeneous. The Kirkland "red flux", a low grade dolomitic hematite bed, occurs 18 feet stratigraphically above the Westmoreland ore bed but the former cannot be seen in the encased shaft of the mine.
Sharp upper and lower bedding plane contacts are typical of the Westmoreland ore. Current ripple marks having a wave length of more than one foot are seen along the upper contact of the oolitic hematite at several places in the mine. Oolitic hematite beds in the south branch of Moyer Creek (See Trip A) exhibit well developed crossbedding. Dale (1953) notes the presence of ripple marks and channel fillings in the overlying fossiliferous Willowvale formation, and both he and Alling conclude that the oolitic hematite beds are integral members of a shallow water marine depositional sequence.
The oolitic hematite consists principally of small ellipsoidal concretions or oolites from one to four millimeters in maximum dimension. Each oolite (Alling, 1947) consists of "onion Skin" layers of fine grained hematite and chamosite (iron-rich chlorite) surrounding a nucleus of well-rounded quartz, calcite, or hematite. The oolitic ore is dominantly a dull (Tuscan) red with some irregular thin lenses and seams of bright red microcrystalline earthy hematite. Interstitial to the oolites is silica (largely quartz, minor chert), dolomite, calcite, glauconite, pyrite, and francolite apatite). Newland and Hartnagel (1908, p. 62) give the following average chemical analysis for oolitic hematite from the mines at Clinton, N.Y.
SiO2 | 12.63
Al2O3 | 5.45
Fe2O3 | 63.00
MnO | 0.15
CaO | 6.20
MgO | 2.77
S | 0.23
P2O5 | 1.50
CO2 | 6.15
H2O | 2.77
Crinoid columnals and tests or brachiopods, cephalopods, bryozoa, and gastropods, all replaced by hematite, are quite common in the ore. Alling (1947) proposes a diagenetic replacement origin for the ore and summarizes the evidence as follows: 1) they (the ores) are of the bedded type in the strictest sense; 2) they are thin, long lenses, which pinch out and come in again; 3) they are very extensive (oolitic hematite beds of this age occur as far west as Wisconsin and as far south as Alabama); 4) they are associated with sediments of shallow-water origin; 5) they are integral members of a stratified series; 6) they are not the result of replacement long after the deposition and lithification of the rocks, otherwise the ores would be "pockety", and the iron would stain the adjacent rocks; 7) many stages of replacement including replacement of fossil fragments by hematite can be seen in thin section; 8) groundwater played no essential part in the formation of the ore. Alling believes that solutions carrying iron, silica, and alumina were introduced into moderately turbulent, yet clear shallow seas and there precipitated by reaction with carbonates, the marine salts, and possibly by bacteria and oxidation. The oolites may represent precipitation of hematite and chamosite (iron-rich chlorite) from a colloidal state during a period of some agitation of the water.

C: PRECAMBRIAN GEOLOGY OF THE ADIRONDACK MOUNTAINS
Purpose: To visit the Remsen, Ohio and Piseco Lake Quadrangles and see several of the Adirondack Mountain lithologies, the Piseco Dome, and smaller structures.
Acknowledgments: The information presented here is based largely on the work of Miller (1909) in the Remsen Quadrangle, Nelson (recently completed field work) in the Ohio Quadrangle, and Cannon (1937) in the Piseco Lake Quadrangle
General: The Remsen, Ohio, and Piseco Lake Quadrangles lie in the southern part of the Adirondack Mountain Highlands Core, and in these quadrangles can be found most of the major lithologies of the Core.

C: PRECAMBRIAN GEOLOGY OF THE ADIRONDACK MOUNTAINS

Terraces
Proceed up slope over several terraces (500-780 feet) of glacial Lake Amsterdam.

Lake Amsterdam terrace
Broad terrace of Lake Amsterdam at foot of Marcy Hill. Bedrock beneath terrace is Utica shale. Marcy Hill, immediately to north, is capped with Frankfort Formation (Ordovician).

Top of Marcy Hill
Adirondack Mountains visible in the distance on a clear day. As we proceed north from Marcy Hill we are traveling down section in the Ordovician formations: Frankfort Formation at the crest of the hill, Utica shale on the north slope, and Trenton limestone group in the broad valley north of the hill.

Lake Herkimer delta
Route cuts through delta (el. 1000 feet) which is part of a large delta plain built into glacial Lake Herkimer.

Morainal belt

Lake Forestport delta
Deltaic deposit of Lake Forestport Elevation 1200feet.

STOP 1. Sillimanite gneiss
Sillimanite gneiss, mapped by Miller (1909) as "syenite-Grenville complex." The dominant rock here is a medium grained gray sillimanite-biotite-quartz-feldspar gneiss. The foliation planes on weathered surface are accentuated by flattened white matts of fine grained fibrous sillimanite (fibrolite), quartz, feldspar, and magnetite. This rock does not resemble any of the syenite gneisses. It is probably a metasediment of the Grenville sequence. Does the presence of sillimanite distributed through this gneiss indicate that the parent rock was sedimentary? Magnetite seems to be more abundant in this rock than in other lithologies of the region. Why is it associated with sillimanite?

STOP 2. Grenville sequence
On southeast side of river, downstream from the bridge, the following steeply dipping interlayers of the Grenville sequence can be seen: medium grained garnetiferous quartzite medium grained rusty weathering diopside-quartz marble graphitic calcareous tremolite-diopside quartzite biotite gneiss silicified metasediments: well defined nearly vertical bedding preserved in a solid mass of quartz which exhibits nearly horizontal jointing. About two hundred yards above the bridge on the southeast side of the river is exposed a sillimanite-biotite-quartz feldspar gneiss.

Trenton group
Cincinnati Creek. Exposures of Trenton group.

Prospect.
Proceed to 4-way intersection northwest of small village triangle. Cross intersection and follow Rt. 287 and signs to Hinckley. The West Canada Creek makes a sharp bend at Prospect, reflecting a postglacial diversion. The West Canada Creek rises in the West Canada Lake region of the Adirondacks and flows southwesterly to Prospect; at Prospect the river turns abruptly southeast and flows through the Trenton Gorge and southeast to the Mohawk River. Presumably the pre-glacial West Canada Creek had a continuous southwesterly course from source to the Mohawk River near Rome; an ice or drift dam deflected the West Canada Creek at Prospect in late glacial time and caused the river to flow southeasterly from this point and cut the Trenton Gorge. At Prospect Falls, just east of the village,there are excellent exposures of fossiliferous Coburg Formation (Trenton group).

Dam across West Canada Creek.
Hinckley Reservoir (Utica water supply) begins here and extends 5 miles upstream.

STOP 3. Coarse grained gneiss
Low hill with outcrops on north side of road. Dirt road from Wheelertown enters main route (287) from north about 100 yards east of outcrop. Coarse grained hornblende-quartz-microperthite gneiss; dominantly pink, some greenish. Note contorted and wavy foliation planes. Mapped by Miller (1909) as "syenite". This rock is more massive than the bulk of the granite and syenite gneisses in the region. This lithology is interesting because it points up the problem of rock nomenclature in the Adirondacks. On the basis of mineralogy, is this a syenite gneiss?

STOP 4. Small quarry
Note that Figure C-2 indicates that this rock is part of the great wedge of granite that tapers westward from the Piseco Dome. Nelson has recently mapped this rock as a mixed Grenville and granite gneiss unit, and notes the migmatitic nature of this exposure. The rock is a medium grained biotite gneiss with augen of pink feldspar and seams of aplitic and pegmatitic material parallel to the foliation. The foliation strikes between north-south and N 60 E, and dips to the west or northwest.

STOP 5. Part of Grenville sequence
Nelson maps this as part of Grenville sequence. The rocks here are coarse grained and gneissic. The dominant lithology is a coarse hornblende-garnet-quartz-plagioclase gneiss. Many large gray crystals of labradorite occur in this gneiss. In places these large crystals and smaller plagioclase crystals in the matrix of the rock exhibit a blue play of colors. The composition of one of the larger crystals was determined to be An52, and it was seen under the microscope to be crowded with small inclusions. (See "Problem" 5 under "Summary of Precambrian of the Adirondack Mountains.")
Interlayered with this hornblende-labradorite gneiss are dark bands of amphibolite and thin bands of biotite gneiss.

STOP 6. Quartz syenite gneiss
Broad outcrops along west side of West Canada Creek. Nelson maps this as equigranular quartz syenite gneiss and notes the presence of streaks of granite and amphibolite. Also present are coarse grained hornblende-feldspar pegmatite bodies. Note sheet structure which dips toward the stream on both banks, thus forming a natural gutter for the stream course. Pot holes on gently sloping rock surface on east bank.

STOP 7. Phacoidal quartz syenite gneiss.
PLEASE BE CAREFUL NOT TO DAMAGE THE CHRISTMAS TREES.
Exposure of dark greenish gray phacoidal quartz syenite gneiss. Texture is best seen on weathered surfaces. Cannon (p. 26) reports calcic andesine "xenocrysts" in syenite at "quarry just east of Morehouseville." This quarry is presumably south of the road. North of the road the gneiss is finer grained, phacoidal texture is not as obvious, and there are a few small pegmatite dikes. Note (Figure C-2) that this stop is about midway on the large east-west trending belt of quartz syenite gneiss that extends across the middle of the Piseco Lake and Ohio Quadrangles. Cannon considers this to be a thick, isoclinally folded porphyritic quartz syenite sill dipping steeply south.

South flank of Piseco Dome
Turn left (east) on Rt. 8. For the next 8 miles Rt. 8 runs along the east-west belt of "porphyritic" quartz syenite gneiss. Prominent row of mountains immediately north and parallel to the road is underlain by equigranular quartz syenite on the south flank of the Piseco Dome.

STOP 8. Lineated granite gneiss
Strongly lineated granite gneiss with sheets of metagabbro. Note that this stop is in the granite gneiss on the western nose of the Piseco Dome. The gneiss in the vicinity of the dome is strikingly lineated; the development of this lineation bears no obvious spatial relation to the faults. Note the elongated and flattened pencils of quartz and feldspar and the difficulty in identifying the "dark minerals" in this rock.
The metagabbro presents a special problem. Cannon (p. 17) notes that these tabular bodies are generally dark gray and fine grained; principal minerals are labradorite (An57), hypersthene, and augite. He postulates that the gabbro intruded the Grenville sequence, and then the granite intruded both; the granite intrusion completely "disintegrated" the Grenville so that the gabbro sills are the only remnants of the older Grenville-gabbro sequence. Smith (1894), however, interprets the gabbro bodies as sills intrusive into the granite. Note: the general conformity between foliation in the granite gneiss and metagabbro contacts; the conformity as to direction and magnitude of plunge of lineation in the gneiss and in the metagabbro; the apparent chill borders of the metagabbro (Cannon says the crystals in the centers of the metagabbro sheets are not coarser grained than those near the borders; the crystals in the center are merely clumped together giving the appearance of larger grain size); locally metagabbro sheets transect the foliation in the granite gneiss; at a few places thin dikes of granitic material cut the metagabbro. Who is right, Cannon,or Smyth?

STOP 9. Piseco Dome cross section
Southeast shoulder of Irondequoit Mountain. Begin STOP 9 which is a series of designated places chosen to exhibit a cross section at right angles to the axis of the Piseco Dome.

Point Comfort State Campsite.
LUNCH HERE IF A GOOD DAY. Lunch served by Methodist Church, Speculator. Bedrock exposed along west side of road is blocky, jointed greenish quartz syenite gneiss; same sill referred to in STOP 9A.

Cross contact
Cross contact between quartz syenite gneiss and granite gneiss.

STOP 9B. Lineated granite gneiss
Outcrop 200 feet west of road. Low ledges and blocky talus of strongly lineated granite gneiss. The axis of the Piseco Dome is in the vicinity of this stop and mileage note 86.5.

Strongly lineated granite gneiss
Strongly lineated granite gneiss plunging gently east-southeast along west side of road; houses close to road on east side.

Cross contact
Cross contact between granite gneiss and quartz syenite gneiss.

STOP 9C. Hornblende-quartz syenite gneiss
Entrance to Little Sand Point State Campsite. About 200 feet north of campsite entrance and 200 feet west of the road is STOP 9C Outcrops of equigranular hornblende-quartz syenite gneiss on the north limb of the Piseco Dome. Note development of hornblende, as contrasted to the mafics in the granite gneiss, and the fact that lineation is not as conspicuous in this gneiss as in the granite. This is the same "sill" as noted at STOP 9A. Note north-dipping foliation.

Contact
Contact between quartz syenite gneiss and granite gneiss along west side of road.

Gentle north dip
Note gentle north dip of strongly lineated pink granite gneiss.

STOP 9D Pink biotite granite gneiss
Outcrops west of road in woods. Lineated pink biotite granite gneiss. Foliation planes dip gently to north.

Contact
Approximate contact between granite gneiss and quartz syenite gneiss on the north limb of the Piseco Dome.

Granite gneiss on left.

Lunch stop.
LUNCH STOP IF RAINY DAY. Piseco Fish and Game Association, Inc. Lunch served by the Methodist Church, Speculator. After lunch trip will continue clockwise around Piseco Lake.

STOP 10. Road cut and broad flat outcrop.
Strongly lineated granite gneiss with some dark bands of amphibolite. Note (Figure C-2) that this granite gneiss corresponds in stratigraphic position to the granite gneiss at STOP 8. The equigranular quartz syenite sills which we saw at STOPS 9A and 9C presumably lie beneath the granite at this stop. Continue southwest from STOP 10; outcrops include quartz syenite gneiss and dark greenish gray biotite granite.

STOP 11. View looking west:
Look west across Piseco Lake along axis of Piseco Dome. Note asymmetry of higher mountains which are underlain by equigranular quartz syenite gneiss. Granite gneiss in core of dome is less resistant and forms lower ground. Note (Figure C-2) that Cannon postulates a normal fault (east side down) along the west edge of Piseco Lake.

Outcrops
Return to main highway and follow Rt. 8 to the southwest. Outcrops of granite gneiss and "porphyritic" quartz syenite gneiss along road between here and next mileage notation.

"Porphyritic" quartz syenite gneiss.

STOP 12. Outcrops on north side of Black Creek
Park near intersection and visit outcrops on Black Creek above bridge about 200 yards upstream from Road 4 (road from Gray north to Wilmurt Corners). NO SMOKING ON THIS PROPERTY, PLEASE. The principal lithology here is garnet-quartz-feldspar-biotite gneiss. Feldspar-rich layers, garnet-rich, and garnet-poor layers, and thin layers of amphibolite give the gneiss a marked banded appearance. Coarse white feldspar augen are present in many of the bands. The gneissic banding strikes about N60E and dips steeply southeast. Note (Figure C-2) that this garnet gneiss is one of the principal Grenville lithologies in the southern half of the Ohio and Piseco Lake Quadrangles. Tight isoclinal folds plunging 20 degrees northeast and involving garnet gneiss and fine grained biotite gneiss are well exposed at one place. At a small peninsula of rock there occurs a coarse augen gneiss containing three or four angular blocks of rusty weathering calcareous amphibolite. Note that the foliation in these amphibolite blocks is discordant to the foliation in the surrounding gneiss; note the angularity of the blocks and the fact that borders of these blocks contain less amphibole than the block as a whole; note tight folding of the gneiss in the vicinity of these blocks. What is the origin of this lithology and structure?

Glacial outwash deposit
Approaching glacial outwash deposit of unknown origin. Its steep,irregular north and east sides rise about 120 feet above the surrounding land to a flat top that has an elevation of 1400 feet. It is perhaps a delta built in contact with wasting ice.

Utica shale and Frankfort formation
Bedrock throughout most of the route from here south to Utica is the Utica shale; the Frankfort formation caps the hills.

D: LITTLE FALLS AREA TO TRENTON GORGE
Purpose: The trip was arranged to permit observation of salient structures and the stratigraphy of formations in this area from the Precambrian through most of the Trenton group. In the sections observed there is evidence for the existence of an Adirondack arch, extending southwest through the Little Falls area.
Acknowledgements: Both the itinerary and the information in the field guide are heavily dependent on the work of Marshall Kay, particularly where the Trenton group is involved. For the Little Falls quadrangle the older work of H. P. Cushing has been used, and James R. Dunn, who has recently remapped the area, helped with the selection and explanation of localities in the field, and provided the summary of its geology for the guidebook. Donald W. Fisher helped with advice in the field, particularly regarding the extent to which Canadian formations are found in this area, and criteria for their identification.
General: The structural behavior of an arch extending southwestward from the south central Adirondacks through the Little Falls - Canajoharie area affected the types of sediment deposited, and whether or not any was deposited (or at least preserved) during the first half of the Ordovician period. Canadian formations, subject to intermittent warping during their deposition in the eastern Mohawk Valley, extend only as far west as Little Falls (Fisher, 1954). Of the Black River group, 230 feet thick in the Black River Valley, only the Lowville limestone reaches this area, and it is absent from Canajoharie eastward to the Amsterdam area (Young, 1943, and Fisher, 1954). Of the Trenton group, the lower formations (Rockland and Kirkfield) thin southeastward toward the arch, and are missing at Canajoharie where the Shoreham rests directly on Canadian strata (Kay, 1953).
The Shoreham is the youngest Ordovician formation to extend as a limestone around the south flank of the Adirondacks. The overlying Denmark, mostly limestone at Trenton Falls, changes eastward through the Dolgeville facies in the Little Falls quadrangle, to the much thicker Canajoharie shale of the eastern Mohawk Valley. The Cobourg similarly undergoes a facies change eastward, thickening and becoming the lower member of the Utica shale, if this may be called Utica (Kay, 1953, p. 46). The influx of argillaceous sediment from the east accumulated in greater thickness east of the arch, suggesting more rapid subsidence there than on the arch and westward from it, and the arch acted as a facies barrier during Denmark time. The muds spread westward across the arch during Cobourg time, though at Trenton limestone is found. Above the Cobourg, the Utica and younger shales indicate that the entire region was depressed and tilted southeastward, the direction in which the shales thicken. Details of this history are discussed in Kay (1953), pp. 74-76).

D: LITTLE FALLS AREA TO TRENTON GORGE

Hills to right and left
Hills across the valley to the right (S) are the escarpment of the Clinton group, and are the northern edge of the Appalachian plateaus. Hills to the left (N) are underlain by Utica shale, and capped by the Frankfort shale.

Large road cuts in black, fissile Utica shale at left.

View of terminal moraine
Knobby hills across the valley to the right (S) are terminal moraine of the Ontarian lobe, a last-gasp glacial advance in this area. This represents its easternmost extent.

Gravelly delta
To the left (N) in a large gravel pit are foreset beds of a gravelly delta. As its top elevation is about 520', it would be assigned to post-glacial Lake Amsterdam of Fairchild.

Climb up 520 foot terrace
Cross West Canada Creek, leaving Herkimer, and climb hill to the top of the 520-foot terrace along the north side of the Mohawk Valley.

Gravel pits
To the left are large gravel pits in lenticular coarse gravel and sand beds.

STOP 1 Moss Island, in Little Falls, N. Y.
The bedrock here is quartzose syenite gneiss of Precambrian age, faulted up on the Little Falls fault block. The same rock forms the cliffs to the south, across the canal. The line of the top of the cliffs is approximately the unconformity on which the Cambrian Little Falls dolomite lies, though the dolomite is not visible from here, in the woods above the cliffs. This raised block of resistant rock formed the pre-glacial divide between the Hudson and St. lawrence drainage basins. However, following melting back of the continental ice sheet to the extent that the Hudson and Mohawk valleys were open, and the St. Lawrence still dammed, this valley drained ice melt-water from the entire eastern Great Lakes (Lake Iroquois). This discharge, probably at least as large as the present Niagara River, cut down the divide here, resulting in its westward shift to Rome, N. Y.
Walk northward across Moss Island. Along most of the northern margin is a complex of enormous potholes cut when the post-glacial Great Lakes drainage spilled over Moss Island in a thundering cataract.

Syenite gneiss
Road cut in Precambrian greenish-gray, brown-weathering syenite gneiss.

Little Falls fault-line scarp
Downgrade toward the east, Rte. 5 crosses the Little Falls fault-line scarp. On the Little Falls block is Precambrian gneiss. East of the fault is Utica shale covered with glacial and alluvial deposits. Cushing estimates the displacement here at between 750 and 850 feet.

Gravel pits
To the left (N) are large gravel pits cut into the side of the 460-foot terrace.

STOP 2 East Canada Creek gorge at Beardslee power station.
FOLLOW LEADERS CLOSELY PAST STATION. DO NOT ENTER STATION OR GO NEAR HIGH TENSION LINES AND TRANSFORMERS.
Water levels permitting. we will go down the steps by the station, cross the creek bed on a concrete wall, and hike for about one half mile up the gorge. Opposite the power station the Manheim fault is well exposed. The displacement is estimated by Fisher (1954, p. 78) to be about 400 feet. Sulphides in the fault zone once led to an abortive attempt to open a lead mine. The upstream (upthrown) wall is Little Falls dolomite. At the base of the downstream (downthrown) wall are a few beds of the uppermost Shoreham limestone (coarse calcarenite) overlain by about 25 feet of the Dolgeville facies, interbedded barren limestones and dark shales between fossiliferous Trenton limestones and overlying black shale. Overlying the Dolgeville beds is the Canajoharie black calcareous shale, equivalent to the Denmark limestone of lower Trenton Gorge (Stop 6).
About 100 feet upstream from the fault are two thin (6") alnoite dikes bearing biotite phenocrysts. In the same locality the dolomite contains a greenish-gray chert bed about 8 inches thick, and an intra-formational breccia bed several feet thick exposed on the wall beside the lower pool.
In the middle area of the gorge, opposite the old mill ruin, there are several large potholes loaded with the tools of their erosion. Just above the area of the potholes is 1 to 2-foot bed of contorted laminated sandy dolomite, with some cabbage-head forms attributed by Dr. Donald Fisher to cryptozoon. In this part of the gorge there are fractures and vugs containing calcite and quartz crystals, and anthraxolite (identified by Dr. James R. Dunn).
Upstream from the broad upper pool the uppermost 10 to 15 feet of the Little Falls formation is the "reddish zone", which contains graded sandstone and intra-formational breccia beds. The overlying Lower Ordovician Tribes Hill formation is composed of fossiliferous limestone and dolomite, commonly muddy and sandy, with a "fretwork" weathered surface. One of the least inconspicuous of the fossils is a gastropod, Ophileta sp. The Tribes Hill formation, about 45 feet thick here (Fisher, 1954, P. 93), forms the ledges for some distance both down and upstream from the old dam.
Overlying the Tribes Hill with a distinct change in lithic type is Lowville limestone, of Black River age, a gray calcilutite. This appears below the newer dam, with its distinctive worm tube, Phitopsis. Here also there are several minor faults, and veins containing pyrite. There are some veins of anthraxolite and quartz crystals, along joint surfaces.
Return to buses by walking south next to the penstock until there is room to pass beneath it.

Manheim fault to left
To the left the bluff is the fault-line scarp of the Manheim fault, which will be seen at close hand at the Beardslee power station.

View of Little Falls fault in distance.
Bluff in the distance to the left (W) is the fault-line scarp of the Little Falls fault. Little Falls dolomite forms the bluff, faulted up against the Utica shale (down on the east).

STOP 3 Disembark for lunch.
Lunch stop. Lunch is being served by the Rebeccas of Dolgeville in their hall to the rear of the brown frame building on the southwest side of the street.

Little Falls fault-line scarp.
Ahead and to the left (W) is the Little Falls fault-line scarp. Precambrian Grenville rock underlies the hills, with down-faulted Trenton limestone and shale opposite on the east.

STOP 4 Basal Cambrian unconformity.
Diamond Hill. Disembark, and walk downstream on the near side of Spruce Creek, to the right of the old bridge.
Little Falls fm. on Grenville gneiss. Conglomeratic basal beds on the upper Cambrian Little Falls formation overlap northward a hill of Grenville quartzose gneiss. Upstream the gneiss occupies an elevation 100 feet or more higher than the basal beds of the Little Falls lying on the gneiss at the foot of the cascades. The initial dip of the Little Falls beds is noticeable.
Shoreham limestone crops out only one half mile WNW at an altitude of 1460 feet. Inasmuch as Grenville gneiss crops out on Diamond Hill at least as high as 1360 feet, only about 100 feet are available for all the formations between the Shoreham and Precambrian. The Little Falls alone is 450 feet thick in cliffs south of the Mohawk River at Little Falls.
MR. D. H. BURRELL, THE OWNER OF THIS PROPERTY, HAS GIVEN US PERMISSION TO BE HERE, AND REQUESTED THAT NO ONE EXCAVATE IN SEARCH OF LITTLE FALLS "DIAMONDS". BE ESPECIALLY CAREFUL NOT TO DEFACE THE NATURAL BEAUTY OF HIS PROPERTY.

Climb through stratigraphic section
The road west climbs up through the stratigraphic section from Little Falls to Utica shale, and back down again as it descends into West Canada Creek Valley at Middleville.

View west into West Canada Creek Valley.
View west into West Canada Creek Valley. Harter and Hasenclever Hills, on the opposite side of the valley, are underlain by Utica shale, capped by Frankfort shale. Precambrian gneissoid syenite crops out in the bottom of the valley at Middleville.

Road cut in Kirkfield and Shoreham limestones.

Road cut in Little Falls dolomite.

STOP 5 Stratigraphic section on "City Brook"
At junction with gravel road, forking downhill to left, stop and disembark, and walk down the gravel road to "City Brook" (Wolf Hollow Brook). This locality is known as Old City.
This section, discussed by Kay (1953), includes much of the Little Falls dolomite, and extends upward through the Lowville, Kirkfield, Shoreham and well into the Denmark formation.
The top of the Little Falls formation is the top of the sandy dolomite stratum in the bed of the creek immediately upstream from the bridge at Old City. Crytozoon is abundant in four feet of dolomite about 60 feet below the top of the formation.
The Canadian strata, present at Stop 1 (45 feet of Tribes Hill fm.), are missing between the Little Falls and Lowville on City Brook.
The Lowville formation forms the lower 26 feet of the cascades and is exposed in the small quarry south of the creek. The lower member, seven feet thick here, is tan-weathering, gray-brown, medium textured, heavy-ledged, tough, sandy and muddy limestone. The upper member, here 19 feet thick, is light-gray-weathering, medium gray calcilutite with some shale partings. A 3-inch metabentonite bed can be seen approximately at the base of the upper member, well exposed about 3 feet above the floor of the quarry. The Lowville is the only member of the Black River group present. The Rockland limestone is not present here, even though it is 13 feet thick above the Lowville at Ingham Mills on East Canada Creek, and 8 feet thick in a quarry one mile northwest of Newport.
The Kirkfield formation, overlying the Lowville here, is interbedded thin-bedded limestone and black calcareous shale, abundantly fossiliferous, about 45 feet thick at City Brook. A metabentonite bed is weathered far back in a recess part way up the falls, about 8 feet above the formation base. The uppermost beds are thick calcarenite strata, some of which have para-ripples.
The Shoreham limestone, overlying the Kirkfield, is 45 feet thick here. The lower part is interbedded thin-bedded shell limestone and calcareous shale, with the trilobite Cryptolithus common a few feet above the base on City Brook. The upper 9 feet, called the Rathbun member by Kay (1953, p. 44), has a basal ledge of calcarenite, above which are interbeds of calcilutite, coquina-calcarenite, and calcareous shale. Below the upper bridge is a zone where the bryozoan Prasopora is large and common.
The basal Denmark beds, of the Poland member, appear in a ledge to the right of the creek as one proceeds about 100 feet upstream from the upper bridge. They are black, irregular, impure bituminous limestone beds in which the cephalopods Geisonoceras, Endoceras, and Trocholites are abundant. About 3 feet above this Trocholites zone is the lowest Poland metabentonite. In its lower 50 feet here the beds are typically Poland in rock type, heavy-ledged, fine-grained, fossiliferous limestone, though there are some relatively barren, knobby-surfaced calcilutite beds. Farther upstream are barren, fine-grained limestone beds intercalated with black calcareous shale, typical of the Dolgeville facies, probably equivalent to the lower Russia member (upper Denmark) at Trenton Falls (Kay, 1953, p. 53).

View of terrace
The conspicuous terrace across the valley to the left (SW) is the result of resistant limestone beds at the base of the Poland member of the Denmark limestone (Kay, 1953, p. 105).

Post glacial lacustrine sediments
Northwest of Newport, there is a low-level floodplain terrace to the right (NE). Higher knobs northeastward are dissected remnants of once continuous varved clay overlain by sand. The top of the clay is persistent at about 800 feet, and the top of the sand at about 1000 feet (Kay, 1953, p. 97). They are post glacial lacustrine sediments.

Basal Poland limestone stratum plain terrace
The basal Poland limestone stratum plain terrace continues across the river to the left (SW).

Kames to the right
Knobs to the right (NE) are probably kames. In some cases, at least, they are composed of sand and gravel (Kay, 1953, p. 97).

STOP 6 Lower end of Trenton Gorge.
Stop at intersection in Trenton Falls hamlet, and disembark. Cross the bridge over West Canada Creek, keeping in narrow file on the upstream side of the bridge. Turn left at east end of bridge, and descend to ledges. The ledges upstream from the bridge are in the lower part of the Poland member of the Denmark formation, and are only a few feet higher than the lowest beds of the Trenton Falls section which Kay has described (1953, p. 27). Here the Poland member is composed of heavy ledges of black, fine-grained, fossiliferous limestone interbedded with fossiliferous calcareous shale. Upstream one hundred yards or so can be seen the two metabentonite beds, about nine feet apart, weathered back into the wall of the gorge. These are the second and third metabentonites in the Poland. The Poland limestone ledges in the stream channel above the bridge are equivalent to the Canajoharie shale above the thin remnant of the Dolgeville facies downstream from the fault at Beardslee power station (Stop 1).

STOP 7. Middle Trenton Gorge.
Turn left before reaching gate, toward parking area by barn. Disembark, and walk up the road through the gate. The ledges exposed in and beside the road are in the upper part of the Rust member of the Cobourg formation. About 300 yards up the road one can look down into the gorge to the right (E) and see the brink of the upper high falls. The base of the Cobourg is at the base of the upper high falls. The Rust member, 115 feet of thin limestone beds intercalated with shale, forms most of the gorge wall here. Just below the parking area and garage-like building at the dam, an abandoned road leads diagonally down the wall of the gorge toward the base of the dam. The weathered road cut is abundantly fossiliferous. From the bottom of this road, above the penstocks below the dam, one can look across the gorge to see the 15-foot contorted zone just below the lip of the spillway. This zone is discontinuous, but appears in varying thicknesses at this horizon in many places on the gorge wall. It is the result of a submarine slide. This is indicated by the coarse calcarenite bed immediately overlying the contorted zone, which fills in hollows and around fragments at its base, and has a comparatively even upper surface. At the top of the eastern gorge wall, above the dam, are the thick beds of the Steuben limestone, the upper member of the Cobourg. In the vicinity of East Canada Creek (stop 1) the entire Cobourg formation and most of the Denmark have changed facies to black calcareous shale in which the contact between the Canajoharie and Utica shales is obscure.

Crest of Marcy Hill
Crest of Marcy Hill, capped by lower Cincinnatian Frankfort shale. The lower slopes of the hill, both north and south, are underlain by Utica shale.

GUIDEBOOK TO FIELD TRIPS
NEW YORK STATE GEOLOGICAL ASSOCIATION
33rd Annual Meeting
Robert G. laFleur
Editor
Contributing Authors
James R. Dunn
Donald W. Fisher
Philip C. Hewitt
Shepard W. Lowman
Lawrence V. Rickard
Host
RENSSELAER POLYTECHNIC INSTITUTE
Troy, N. Y.

A: GLACIAL FEATURES IN THE VICINITY OF TROY, N.Y.
by Robert G. laFleur
Dept. of Geology, Rensselaer Polytechnic Institute
2010: No actual trip is described in the Guidebook, however a number of "Selected Exposures" are. Their locations are often not well constrained. Only some have been found, sometimes using considerable guesswork.

STOP 1. Drumlins
Dozens occur between the Wynantskill and Moordenerkill in the towns of North Greenbush, East Greenbush, and Schodack. Long axes trend about N20W. See Plate II.

STOP 2a. Esker at Moule's Lake
Eskers. Many occur throughout the Albia-Burden Lake moraine. The most typical are at Moule's Lake, Coopers Pond and West Sand Lake. Two others feed the Schodack Terrace at East Greenbush and along the Vlockie Kill. Esker deltas are extensively excavated 2 miles ESE of West Sand Lake.

STOP 2b. Esker at Coopers Pond
2. Eskers. Many occur throughout the Albia-Burden Lake moraine. The most typical are at Moule's Lake, Coopers Pond and West Sand Lake. Two others feed the Schodack Terrace at East Greenbush and along the Vlockie Kill. Esker deltas are extensively excavated 2 miles ESE of West Sand Lake.

STOP 2c. Esker at West Sand Lake
Eskers. Many occur throughout the Albia-Burden Lake moraine. The most typical are at Moule's Lake, Coopers Pond and West Sand Lake. Two others feed the Schodack Terrace at East Greenbush and along the Vlockie Kill. Esker deltas are extensively excavated 2 miles ESE of West Sand Lake.

STOP 2d. Esker at East Greenbush
Eskers. Many occur throughout the Albia-Burden Lake moraine. The most typical are at Moule's Lake, Coopers Pond and West Sand Lake. Two others feed the Schodack Terrace at East Greenbush and along the Vlockie Kill. Esker deltas are extensively excavated 2 miles ESE of West Sand Lake.

STOP 2e. Esker along Vlockie Kill

STOP 2f. Esker delta pit
Esker deltas are extensively excavated 2 miles ESE of West Sand Lake.

STOP 3a. Kame SE of Wynantskill
Kames. Exposed along Rt. 66 SE of Wynantskill, south of Eagle Mills, and E. of the Wynantskill at West Sand Lake. Solitary kames occur one mile north of Poestenkill.

STOP 3b. Kames south of Eagle Mills
Kames. Exposed along Rt. 66 SE of Wynantskill, south of Eagle Mills, and E. of the Wynantskill at West Sand Lake. Solitary kames occur one mile north of Poestenkill.

STOP 3c. Kames at West Sand Lake
Kames. Exposed along Rt. 66 SE of Wynantskill, south of Eagle Mills, and E. of the Wynantskill at West Sand Lake. Solitary kames occur one mile north of Poestenkill.

STOP 3d. Solitary kame

STOP 3e. Solitary Kame

STOP 4a. Ice contact north of Sheer Road
Several ice contacts cross the Albia-Burden Lake moraine. Three (in order of sequence) occur (1) north of Sheer Rd., (2) one mile SE of West Sand Lake, and (3) along Rt. 154 at Moule's Lake. All of these contacts are fed by eskers some of which are a mile in length.

STOP 4b. Ice contact SE of West Sand Lake
Several ice contacts cross the Albia-Burden Lake moraine. Three (in order of sequence) occur (1) north of Sheer Rd., (2) one mile SE of West Sand Lake, and (3) along Rt. 154 at Moule's Lake. All of these contacts are fed by eskers some of which are a mile in length.

STOP 4c. Ice contact at Moule's Lake
Several ice contacts cross the Albia-Burden Lake moraine. Three (in order of sequence) occur (1) north of Sheer Rd., (2) one mile SE of West Sand Lake, and (3) along Rt. 154 at Moule's Lake. All of these contacts are fed by eskers some of which are a mile in length.

STOP 5. Schodack Terrace.
Extensively developed through the Town of Schodack. Kamey in part with large kettles and a few short eskers. Deltaic sediments exposed along the western edge.

STOP 6a. Hampton Ice-margin delta.
Exposed at Hampton Park and one mile east of Rensselaer. Extensive gravel pits at both localities. Especially good bottomset structures at the latter.

STOP 6b. Rensselaer Ice-margin delta.
Exposed at Hampton Park and one mile east of Rensselaer. Extensive gravel pits at both localities. Especially good bottomset structures at the latter.

STOP 7. Superglacial kame terrace
Superglacial kame terrace and ground-laid ice-border outwash gravels are extensively exposed in a pit south of Williams Rd., North Greenbush. Terrace is continuous south to Defreestville where it terminates in a small delta.

STOP 8a. Lacustrine varved clays
Lacustrine varved clays with interbedded sands underlie a large area west of Rt. 4 and the Boston and Albany tracks. Good exposures are limited but occur along the entrance road to the paper company just north of Castleton ...

STOP 8b. Lacustrine varved clays
Lacustrine varved clays with interbedded sands underlie a large area west of Rt. 4 and the Boston and Albany tracks. Good exposures are limited but occur [...] along Mill Creek north of Rysedorph Hill...

STOP 8c. Lacustrine varved clays
8. Lacustrine varved clays with interbedded sands underlie a large area west of Rt. 4 and the Boston and Albany tracks. Good exposures are limited but occur [...] along Spring Street where about 35 feet of clay overlying gravel is exposed in a pit.

STOP 9a. Beaches
The Lake Albany beach is well developed, with frequent storm ridges, at (1) one mile SE of South Schodack [...] Gravel pits provide cross-sections through the beach at all of these locations.

STOP 9b. Beaches
The Lake Albany beach is well developed, with frequent storm ridges, [...] along the Wedge of the Schodack terrace between Brookview and East Greenbush [...]. Gravel pits provide cross-sections through the beach at all of these locations.

STOP 9c. Beaches
9. Beaches. The Lake Albany beach is well developed, with frequent storm ridges [...] from Defreestville E of Rt. 4 north along Blooming Grove Rd. Gravel pits provide cross-sections through the beach at all of these locations.

STOP 10. Peat bog
Peat bogs are common throughout the area. Peat is presently being dug from a bog one mile SE of West Sand Lake.

STOP 11a. River terrace
River terraces are best developed along the Poestenkill between Eagle Mills and Troy, and also ....

STOP 11b. River terrace
River terraces are best developed along the Poestenkill between Eagle Mills and Troy, and also ....

STOP 11c. River terrace
River terraces are best developed along the Poestenkill between Eagle Mills and Troy, and also...

STOP 11d. River terraces
River terraces are best developed [...] , and also along the Wynantskill in Albia.

STOP 12a. Post-glacial rock gorges
Post-glacial rock gorges with falls are found on the Poestenkill near Pawling Ave. in Troy...

STOP 12b. Post-glacial rock gorges
12. Post-glacial rock gorges with falls are found [...] on the Wynantskill along the Airport Rd. in Troy...

STOP 12c. Post-glacial rock gorges
Post-glacial rock gorges with falls are found on [...] Mill Creek along Rt. 151 near Rensselaer.

STOP 13a. Panoramic view of Hudson Valley
13. Promontories at Teller Hill near Sherwood Park [...] offer panoramic views of the Hudson Valley.

STOP 13b. Panoramic view of Hudson Valley
Promontories at [...] Rysedorph Hill, [...] offer panoramic views of the Hudson Valley.

STOP 13c. Panoramic view of Hudson Valley
Promontories at [...] Prospect Park in Troy offer panoramic views of the Hudson Valley.

B: SOME ASPECTS OF TURBIDITE SEDIMENTATION IN THE VICINITY OF TROY, NEW YORK
By Shepard W. Lowman
Dept. of Geology, Rensselaer Polytechnic Institute
In the course of geologic field work in the vicinity of Troy, New York, much interest and controversy have been evolved locally on the subject of deep water flow sediments, generically called turbidites. Numerous and highly varied types of turbidites are exposed within the immediate environs of Troy. Complicating factors in field mapping are the Logan Line thrust fault and the sharp local folding both of which produce tectonic breccias and otherwise complicate the definition and identification of stratigraphic units.

STOP 1. Deepkill Euxinic Assemblage
The first stop will be at the type locality of the Deepkill, one-quarter mile east of Grant's Hollow, ten miles north of Troy on Route 40.
The upper Deepkill is separated from the lower by a covered interval of 800 feet, and its rocks comprise a different assemblage from the euxinic lower Deepkill. The upper Deepkill is a series of mud flows, clay-in-clay brecciolas, a few lime-in-clay brecciolas, porcelanites, and thin beds of chert. Near the bottom of the section there is a small amount of graptolitic black shale and dark gray limestone. This part of the Deepkill is mentioned because its proximity makes it available for those who may be more interested in spending a half-hour on this additional sedimentary type than in collecting graptolites and turbidites from the lower Deepkill.
Both the top and the bottom of the lower Deepkill are covered. The part of the section which is exposed is made up of black shale, gray shale, light gray thin bedded siltstones in banks one to four feet thick, and various types of brecciolas and graded beds.
This assemblage appears to be produced by two sets of factors. First, the underlying euxinic chemical environment dominated by H2S affects Eh much more than pH (Krumbein and Garrels 1952). This permits the accumulation of lime mud at one time and sapropelitic black mud at another depending on alternating chemical controls that are related to tectonic activity on the basin margin. An example is the Black Sea where the lime muds overly sapropelitic ooze (black organic shale) and the two are separated by a thin layer of terrigenous sand (Archanguelsky 1927). The second set of factors are those which produce turbidites of various kinds, brecciolas and graded beds of one kind or another depending on the speed of flows from the upper parts of continental slopes triggered by faulting or by overloading of metastable shelves. More gentle currents from continental shelves would bring a steadier supply of sand and silt to build the banks of thin bedded siltstones.
When turbidity flows were in action and diluted the euxinic environment, then lime muds or organic ooze would not be present as pure rock types, but when the flows died down the euxinic deposits would form the dominant rock type with alternation from lime to mud to organic ooze, and with an occasional turbidite flowing into the depositional area from one side of the basin or the other,
The faunal evidence as analyzed by Ruedeman fits well with the postulated euxinic environment. The predominant fossils are graptolites which are thought to be pelagic or pseudopelagic (i.e. living attached to seaweed). Other fossils are rare and are thin shelled chitinous forms which appear to be well adapted to a pseudopelagic environment. Other bottom dwelling types are wanting in the shales, silts, and calcilutites.

STOP 2 - OVERVIEW
Schodack Brecciola Assemblage: See Figure 3. Four brecciolas are described which apparently belong to the Schodack (West Castleton) Formation. These are typically developed at the following locations: School 14, west edge of playing field at 13th St. and College Ave., Sage Avenue, 250 feet west of 15th Street, R.P.I. Campus, east end of football field, and Troy High School, northwest corner of athletic field. All four occurrences appear to be distinctive, and they are not noticeably lenticular like the brecciolas of the upper and lower Deepkill some of which lens out across the outcrop. The Sage Avenue brecciola occurs at four localities one-half mile apart, and is clearly recognizable at each locality. The Troy High School sequence of brecciolas occurs in two extensive outcrops, approximately 800 feet apart, at both of which it possesses the same distinguishing characteristics. All four brecciolas are sharply distinct from one another, except that all are ten to twenty feet thick without marked lenticularity. They differ in this respect from the Deepkill brecciolas, which are inches thick and sharply lenticular. The brecciolas described by Migliorini in the Apennines appear to be closer to the Deepkill variety than to those of the Schodack. The Grand Banks brecciola of 1929 was calculated to be 16 to 40 inches thick. By comparison, the Schodack brecciolas are unusually large, although not to be compared to the Rysedorph megabreccia facies of the Snake Hill (Middle Ordovician) (J.G. Elam, 1960 unpublished).

STOP 2A. School 14 locality
(North of College Age. along an extension of 13th Street at west edge of playground of School 14.) One hundred feet of outcrop extends north-south, strikes N25E and dips 45° southeast with the top of the section to the southeast as judged by graded bedding. The south end of the outcrop is a pale, gray-green quartzite, poorly sorted and mostly fine grained. The MATRIX is a brownish purple, fine grained sandstone or siltstone with frequent coarse, round, sand grains and some clay, much calcareous dust and small calcareous fragments, many blobs of clay varying from black to light gray, and also with frequent light gray calcareous granules. The FRAGMENTS are coarse-grained, light-gray, massive, and fossiliferous limestone varying in shape from irregular to round to tabular. Average size is 2"-5" with some longer dimensions up to l5". There are also a few large slabs the largest of which is two feet thick and eight feet long. The general orientation of fragments is subparallel to the boundaries of the main flow. Abundant small clay blobs about 2" across are also found, along with some dense light gray limestone fragments and a few sandy fragments. At the north end of the outcrop the ratio of pebbles to matrix is about 30:70 varying to 20:80 near the middle, and dropping to 10:90 at the south end of the brecciola outcrop. This indication of grading suggests the beds are right side up with the top to the south east.

STOP 2B. Sage Avenue locality - 15th Street occurrence.
The outcrop is buried beneath the buildings along 15th Street in the vicinity of the 15th Street Lounge. Large boulders 4' by 6' were blasted from an old quarry wall and moved by bulldozer to their present location between the South Parking Lot and the tennis courts. There is one predominant type (TYPE 1) of rock, which makes up about 90% of the boulders and there are several subsidiary types. TYPE 1. FRAGMENTS: About 80% of the fragments are coarse grained, fossiliferous, light gray, limestone, averaging 4" to 6" in size, irregular to sub-spherical in shape, with no linear distribution, and with no noticeable grading. Since the occurrence is a pile of boulders there are no observable stratigraphic relationships. Minor constituents are small fragments of light gray, dense limestone and sandstone of which the former is more abundant. MATRIX is a brown-weathering dolomite mud with numerous medium to coarse, rounded sand grains. About 20 to 50% of the matrix is composed of light gray, dense, calcilutite fragments averaging 0.25" in diameter. These give the matrix the appearance of a pebble conglomerate. The relative abundance of matrix and fragments is variable from boulder to boulder but the general average is about 60% fragments, not counting the 1" calcilutite fragments that appear to make up a considerable part of the conglomeratic matrix.

STOP 2C. R.P.I. Campus locality
(12' brecciola outcropping on R. P. I. campus east of football field) The general dip of 20° to the east places this brecciola beneath the "Sage Avenue brecciola". It is underlain by greenish-gray clay with interbeds of dolomitic fine-grained sandstone two to three inches thick and six to ten feet apart. The brecciola is overlain by greenish-gray shale with thinly interbedded siltstone or very fine grained sandstone. The interval from the top of the "campus brecciola" to the base of the "Sage Avenue brecciola" appears to be 15 to 30 feet, with the latter being the younger of the two. MATRIX is dark gray, flow-streaked mudstone. No evidence is seen of stratigraphic differentiation, graded bedding, or direction of flow. FRAGMENTS are predominantly (80%) coarse grained light gray, fossiliferous limestone, ranging in size from 2" to 1.5 feet, irregular in shape and with no preferred orientation. There are a few small fragments of dense light gray limestone, about one per cent by volume. Medium grained, rounded sandstone makes up about 20% of the fragments with irregular distribution and no preferred orientation. FRAGMENTS & MATRIX: Relative percentage of fragments to matrix is 4O:60 to 50:50: Evidence of scour is seen in the presence of green clay blobs in the lower part of the flow. Load casts are also present in the form of green clay injected into the base of the brecciola. STRATIGRAPHIC CORRELATION: This brecciola is lithologically closely similar to the lower brecciola at Dunn Garden Apartments (Hoosick & Burdett). It also falls in the same succession of beds and is thought to be stratigraphically equivalent.

STOP 2D.

STOP 2E. North side of Beman Park

STOP 2F. Dunn Garden Apartments.

STOP 2G. Troy High School Playing field.
(Sequence at the east end of the track and playing field north of Troy High School on Burdett Avenue.) Strike of these beds is N15E, dip is 75 west, top of the stratigraphic section is to the west, The brecciola sequence is made up of three members with eleven submembers. It is overlain by thin bedded, fine grained sand and shale with a possible thickness of 200 feet. The brecciola sequence is underlain by brown weathering green claystone with dark gray wispy interbeds, having a possible thickness of 300 feet. The thickness of the brecciola sequence is approximately 90 feet. The Troy High School outcrop is the most extensive and gives the best picture of both the brecciola and the beds associated with it. Brecciola Sequence (in descending order) Bed 3b; Mostly covered but with occasional patchy outcrops of dense, light gray limestone fragments in a dark gray clay matrix. A large outcrop that is probably stratigraphically equivalent occurs at the southeast corner of Burdett Avenue and West Peoples Drive., This outcrop has a ratio of fragments to matrix of about 15:85; the fragments are uniformly light gray, dense limestone, 2" to 3'" thick, 8" long, and randomly oriented. The matrix is uniform dark gray claystone. 3a. Thin bedded light gray dense limestone, interbedded with thin beds of dark gray shale. Unit is regularly bedded but slightly disturbed, giving the appearance of layers being slightly pulled apart in sedimentary boudinage. This occurrence, which is 2 feet thick and over 8 feet long, may be a large mass that slid or flowed some distance without turbulence, or it may have slid only a few inches or feet, but enough to cause the disturbance noted. Similarly bedded limestone in a similar stratigraphic position occurs about 500 feet to the east across the High School playing field. Bed 2e. Three feet of tan weathering green claystone with numerous black wispy streaks that show flow bedding. 2d. One and one half feet of light gray, dense limestone fragments in a dark gray matrix with 10:90 ratio, fragments are 2 by 6 inches and randomly oriented. 2c. Two and one half feet of tan weathering green claystone. 2b. One foot of green clay blobs (1" to 2") in maroon weathering clay matrix; ratio 20:80. 2a. Seven feet of green clay with black wispy interbeds and one interbed of coquina one inch thick with worm borings, giving supporting evidence of top and bottom. Bed 1d. Four feet of light gray dense limestone and black shale fragments in a rusty, medium-grained, rounded sand matrix with a 20:80 ratio. Fragments and trains of fragments are subparallel to the margins of the flow. A small percentage of the limestone fragments are granular and fossiliferous. A few others are light brown and well-bedded. Average size of limestone fragments is 3 by 6 inches. 1c. One foot thick, similar to above but with sand and clay matrix 50:50, and showing an increase in the percentage of limestone fragments to matrix, to about 40:60. 1b. Black shale boulder one foot thick and eight feet long, oriented parallel to the margins of the brecciola. 1a. Brecciola bed five feet thick, ratio of limestone fragments to clay matrix is 80:20. Orientation of fragments is sub-parallel to the boundaries of the brecciola. The limestone fragments are mostly dense light gray limestone, granular fossiliferous light gray limestone, and light brown well-bedded limestone in a ratio of 60:20:20. The matrix is dark gray clay. SYNOPSIS OF MAIN BRECCIOLA MASS (Beds 1a-1d) GRADED BEDDING. The sand matrix shows incipient grading above bed lc which is mixed sand and shale. The main mass of the flow 1a-1d shows marked increase in the abundance of limestone fragments downward through the flow. OTHER CRITERIA OF TOP AND BOTTOM. Worm borings: as noted under 1a. Scour: the basal portion of 1a shows many wispy blobs of green clay that appear to have been scoured from the underlying green clay beds while they were unconsolidated. STRATIGRAPHIC DIFFERENTIATION. MATRIX: The sand and clay matrices appear to be well differentiated stratigraphically FRAGMENTS: The fragments are less well differentiated than the matrix but they do show a notable differentiation from the top to bottom. Toward the top of the bed, the limestone pebbles are mostly calcilututes while at the base the pebbles contain about 10% of calcarenites. The pebble-to-matrix ratio is perhaps 20:80 toward the top, increasing to 80:20 toward the base. At the top of the main brecciola the matrix is nearly pure sand; this changes gradationally downward to sandy clay and to nearly pure in clay in the base of the flow. Correlation of separate outcrops on the west and east sides of the athletic field is satisfactory. On the west side the units are oriented from top on the west to bottom on the east; on the east side the orientation of the same sequence has the top on the east and bottom on the west. In spite of this structural complication the correlation of the various brecciola units can be made in some detail.

C: SILURIAN AND DEVONIAN ROCKS OF THE CENTRAL HUDSON VALLEY
By James R. Dunn
Dept. of Geology, Rensselaer Polytechnic Institute
and
Lawrence V. Rickard*
N.Y. State Geological Survey, Albany, N.Y.
Limestones, shales, sandstones, and conglomerates comprise the Silurian and Devonian sequence of the Hudson Valley. Only the youngest portion of the Late Silurian is represented (Rondout Formation), whereas most of the Early and all of the Middle Devonian is present. Late Silurian (Cayugan Series) rocks are thin, and rest unconformably upon folded and eroded Middle Ordovician shales and sandstones. The Early Devonian rocks are divided into the Helderbergian and Ulsterian Series (Rickard, in press), and consist of limestones in the lower part and shales and sandstones in the upper portion. The overlying Middle Devonian sequence (Erian Series) begins with the Onondaga Limestone and continues above into marine and non-marine shales and sandstones of the Hamilton Group. Fossils are common throughout most of the Silurian-Devonian sequence of the Hudson Valley. Marine assemblages are particularly rich in the Helderberg limestones, the Onondaga Limestone and the lower, marine portion of the Hamilton. Plant fragments are the only abundant fossils in the non-marine rocks near the top of the sequence.
*Published by permission of Ass't. Commissioner, N. Y. State Museum and Science Service

STOP 1A. Callanan Road Improvement Company Quarry, NE part.
Outcrop has Normanskill shales, siltstones, and graywackes at the base, overlain by the full thickness of the Rondout Formation and 12 feet of the Manlius Formation. All units are essentially conformable even though they are of Ordovician, Silurian (7) and Devonian ages. Of particular interest are the abundant Tentaculites in the lower unit of the Manlius Formation and the transparent obtuse rhombohedrons of calcite associated with quartz crystals in the Rondout Formation.

STOP 1B. Callanan Road Improvement Company Quarry, center.
The walls of the quarry have typical Hudson Valley thrust fault structures. The Rondout, Manlius, Coeymans and part of the Kalkberg formations are exposed in the walls of the quarry. Plate VI is a picture of the quarry, looking south, in which the faults and formations are indicated.

STOP 2. Synclinal structure
New Scotland Limestone, Becraft Limestone, Glenerie Sandstone and Chert (Oriskany) and Esopus Shale are exposed. The Becraft Formation is thrust over the Glenerie Formation at the east side of the structure, and a zone of cleavage and shear in the Becraft branches north-northwestward from the thrust fault. Plate V is a map of the area and Plate II shows a cross-section through the structure which was core drilled about 10,000 feet southeast of Stop 2.

STOP 3. An exposure of the Esopus Formation in a cliff.
The Glenerie Formation and the Becraft Formation are exposed at the base.
2010: It appears that this cliff has been consumed by quarrying operations.

STOP 4A. Mt. Marion beds, lower part.
The exposure is in an old quarry from which flagstone was produced. Brachiopods and Tentaculites are abundant.

STOP 4B. Mt. Marion Sandstone, upper part.
The exposures are in a quarry from which flagstone was produced. Lack of marine fossils and the fairly common plant remains suggest non-marine origin.

STOP 5. Onondaga Reef.
This is one of the reefs which is typical of the Onondaga Formation in New York. Fossil collecting is excellent.

STOP 6. Broncks Lake stratigraphic section.
All units of the Kalkberg Formation are exposed but not fully. All of the New Scotland and Becraft Formations can be seen, and 24 feet of the Alsen Formation is visible. The strata dip steeply westward and are cut by a fault which repeats part of the Kalkberg Formation.

D: STRATIGRAPHY AND STRUCTURE IN THE SOUTHERN TACONICS (RENSSELAER AND COLUMBIA COUNTIES, NY)*
By Donald W. Fisher
Geological Survey, N.Y. State Museum and Science Service, Albany, N. Y.
"The structural [and stratigraphic] investigation of the Taconic region is only in its beginning stages, and ... the interpretation of one particular area, to be satisfying, should allow correlations with adjoining areas. In this region of dense underbrush, extensive forests, widespread till cover, low relief, and few fossil localities, facts and observations are hard to accumulate, and their interpretation is beset with difficulties."
*Published by permission of the Assistant Commissioner, New York State Museum and Science Service.

STOP 1. Slump blocks of Austin Glen
Slump blocks of Austin Glen Graywacke and Trenton Limestone in badly deformed Snake Hill Shale.

STOP 2a. Greenish-gray slaty argillite of Mettawee Formation.

STOP 2b. Vertical beds
Interbedded black shale, limestone and calcareous sandstone, beds nearly vertical, Lower Cambrian.

STOP 2c. Grayish-green slaty argillite of Mettawee Formation.

STOP 2d. Vertical beds
Principally on west-bound lane; essentially vertical beds of interbedded black shale, limestone and calcareous sandstone, probably Lower Cambrian.

STOP 2e. Nassau Formation
Principally on westbound lane; purple and green shales with interbedded thin red and green siltstones. Nassau Formation.

STOP 2f. Walloomsac (?)
Black slate, presumably Walloomsac, no fossils yet found, purple and green Nassau beneath, along town road. Nature of contact disputable.

STOP 2g. Anticline in Walloomsac (?)
Anticline in black slate (Walloomsac ?) on east-bound lane. Amos Eaton born at New Concord (Historic marker), 1.1 miles south of East Chatham.

STOP 2h. Mile of Stockbridge dolomites
Along both lanes; 1 mile of exposures of eastward dipping Stockbridge dolomites and dolomitic limestones, locally much deformed.

STOP 3. Eastward dipping Stockbridge carbonates

STOP 4. Balmville and Austerlitz
Fossiliferous Balmville Limestone on dolomite and underneath Austerlitz purple and green phyllite.

STOP 5. Austerlitz
Eastward dipping Austerlitz purple and green phyllite with interbedded thin green chloritic quartzite, black slate outcrops 500' to the west along the R.R.

STOP 6. Austerlitz, Stockbridge, Balmville
In tunnels of the B. & A. R.R.; Austerlitz purple and green phyllite thrust on Stockbridge carbonates, fossiliferous Balmville Limestone locally present.

STOP 7. "Berkshire" black phyllite.

STOP 8. Rensselaer Graywacke
Rensselaer Graywacke with many quartz veins, some of which are feldspar-bearing.

STOP 9. Pine Plains
Interbedded dolomite and shale with ripple marks (?) or flow structure (?) on dolomite, Pine Plains Formation.

STOP 10. Everett Schist
Taconic State Park, green Everett Schist on north side of N. Y. 344 at eastern edge of Park.

STOP 11. Copake and Balmville
Copake Limestone and Balmville Limestone with distorted fossils due to flowage.

STOP 12. Balmville Limestone thrust on Walloomsac Slate

STOP 13. Argillite and quartzite
Green argillite (Elizaville) and chloritic quartzite (Curtiss Mountain) along both sides of Parkway

STOP 14. Germantown
Exposures on both sides of U.S. 9, 0.5 mile south of southern edge of Becraft Mountain; interbedded graptoliferous black shale and limestone (Germantown Fm.) and greenish-gray silty shale with Deepkill graptolites.

STOP 15. Normanskill
Red and green shale and much green chert, lower member of Normanskill Group.

STOP 16. Germantown
Ferruginous quartzite overlying quartzose greenish-gray shale (Germantown Fm.)

STOP 17. Deformed Mt. Merino Shale of Normanskill Group.

STOP 18. Germantown and Mettawee
Interbedded black shale, limestone and limestone brecciola of Germantown Fm. overlying Mettawee green argillite.

STOP 19. Type locality of Stuyvesant Falls Fm.
Type locality of Stuyvesant Falls Fm.; interbedded green silty shale and flow-cast green siltstones and chertified argillite underlying Mt. Merino shale of Normanskill Group.

STOP 20. Type locality of Schodack fm.
Grayish-green argillite (Mettawee) with fossiliferous limestone brecciola (Stuyvesant Conglomerate) near top, Mettawee overlain by laminated siltstones and interbedded black shales. Type locality of Schodack Formation.

STOP 21. Type locality of Normanskill
Type locality of the Normanskill; gray and black shale with interbedded graywacke.

STOP 22. Type locality of the Deep Kill Formation
Type locality of the Deep Kill Formation; interbedded limestone and black shale in lower portion and greenish-gray shale in upper portion overlain by red shale of basal Normanskill. A reverse fault here repeats a portion of the section.

STOP 23. Type locality of Schaghticoke Formation
Type locality of Schaghticoke Formation; interbedded green and black shale and thin limestones and siltstones, all badly deformed.

GUIDEBOOK TO FIELD TRIPS
NEW YORK STATE GEOLOGICAL ASSOCIATION
34th Annual Meeting
Port Jervis, New York
May 4-6, 1962
Wilbur G. Valentine, Editor
Contributing Authors
Helen Antine-Biren
Sidney Fink
Frank W. Fletcher
Elizabeth and Howard Jaffe
John H. Johnsen
William A. Oliver Jr.
Christopher J. Schuberth
John, B. Southard
HOST
Department of Geology
Brooklyn College
Brooklyn 10, N. Y.
Additional copies available from Permanent Secretary of the New York State Geological Association
Kurt E. Lowe
The City College'
New York 31, N.Y.

A: THE ONONDAGA LIMESTONE AND THE SCHOHARIE FORMATION IN SOUTHEASTERN NEW YORK
William A. Oliver, Jr.
John H. Johnsen.
John B. Southard.
.
Correlation and facies changes in the Schoharie, and Onondaga Formations; relationship to the Esopus Formation; relationship of the outlier at Highlands Mills to the main belt along the Catskill Front.

A: THE ONONDAGA LIMESTONE AND THE SCHOHARIE FORMATION IN SOUTHEASTERN NEW YORK

STOP 1. Erie Railroad Cuts near Highland Mills
Railroad cuts just north of Pine Hill road, NW ninth of Popolopen Lake 7.5' quadrangle, Schunemunk 15' quadrangle.
The contacts between the Highland Mills Member, the middle member, and the Woodbury Creek Member are marked with white paint on the railroad cut.
Watch out for trains.
Although there is a complete section of the Esopus Formation, (p. 13) and the Kanouse sandstone exposed on the east side of the New York Thruway one-half mile east of Highland Mills, the stop will be made at the cut on the Erie Railroad a few hundred yards west of the Thruway, because of traffic danger on the Thruway. Here the Highland Mills Member, the middle member, and the lowest 60 feet of the Woodbury Creek Member (p. 14) are exposed. One-half mile north, the upper non-conglomeratic part of the Kanouse sandstone (p. 14) is exposed on a steep slope just east of the railroad.

STOP2. Leeds Gorge
(Not visited as part of the 1962 trip, but in the Guidebook.)
Gorge of Catskill Creek, just west of Mill Pond in Leeds, SE corner, Leeds 7.5' quadrangle, Coxsackie 15' quadrangle.
Onondaga Formation
This is one of the most complete sections of the Onondaga in the trip area. With a steep easterly dip, the lower 115 feet, conformably overlying the Schoharie Formation, are exposed in a fairly short distance in the bed of the creek. Although the formation is well exposed, only a short time will be devoted to the Onondaga at this stop. Facies changes between here and Kingston (stop #4) are minor and the nature of the rocks and the fossils can be observed to better advantage at that place.
The Leeds Gorge section is as follows:
Moorehouse Member (upper part not exposed):
25'+ | Middle unit; medium-dark-gray, fine-grained limestone with abundant dark-gray chert; corals and bryozoans common, brachiopods and other fossils present.
12' | Lower unit; light-medium-gray, medium-grained limestone with no chert; corals common; other fossils present.
Nedrow Member:
4' | Light-medium-gray, medium-grained limestone with few chert nodules; platyceratids, corals and brachiopods. This unit is lithologically and faunally transitional to the Moorehouse.
39' | Light-medium-gray, medium-coarse and fine-grained limestone with abundant light-medium-gray chert; platyceratids, corals and brachiopods.
Edgecliff Member:
32' | Light-medium and light-gray, medium-coarse and coarse limestone with abundant light-medium-gray chert; large crinoid columnals common, corals, and brachiopods.
3' | Medium-gray, fine-grained limestone with no chert; fragmental fossils.
Transition to Schoharie Formation:
1.5' | Alternating limestone-and gritty limestone.
Schoharie Formation | The entire Schoharie Formation is excellently exposed at the falls in the gorge of Catskill Creek. The strata are nearly vertical to overturned.
Saugerties Member:
1.6' | Interbedded light-grey weathering limestone and yellowish-brown weathering muddy limestone; proportion of less pure limestone beds decreases upward; purer limestone beds are continuous layers except for a few layers of limestone nodules in lower part; grades up into Onondaga Limestone.
Aquetuck Member:
40' | Yellowish-brown weathering dark gray, calcareous mudstone, becoming sandy and glauconitic in uppermost 3 feet; interbedded light weathering muddy limestone beds not sharply set off from the mudstone; abundant indistinct layers of dark weathering rock and layers of small chert nodules.
Carlisle Center Member:
13' | Yellowish-brown and yellowish-gray weathering dark gray calcareous mudstone with interbedded lighter weathering slightly limier layers; glauconite and quartz sand, both in upper part and lower part, but not in middle; "black bed" (p. 11 ), 3 feet thick, 5 feet from base. Abrupt contact with underlying Esopus Formation.

STOP 3, New York Central Railroad Cut, Kingston
Cut on the N.Y.C. (West Shore) Railroad, just north of West O'Reilly Street, Kingston West 7.5' quadrangle, Rosendale 15' quadrangle.
Cuts on both sides of the track a few hundred feet north along the track. Contacts between members of the Schoharie are marked with white X's on both sides of the track. The top and bottom of the black bed in the Carlisle Center Member are shown by paint marks along the bedding.
LISTEN FOR TRAINS - they come by often.
The entire Schoharie Formation is excellently exposed in a small syncline beneath the Edgecliff Member of the Onondaga Limestone.
The section is as follows:
Saugerties Member:
30' | Interbedded light-gray weathering limestone and yellowish-brown weathering muddy limestone; prominent banding shown on surfaces of cut; possible to recognize several subunits.
Aquetuck Member:
44' | Yellowish-brown and yellowish-gray weathering very calcareous mudstone or very muddy limestone; interbedded layers of light-gray weathering limestone nodules; a few continuous limestone layers; thin inconspicuous dark-weathering layers in the calcareous mudstone.
Carlisle Center Member:
143' | Yellowish-brown and yellowish-gray weathering calcareous mudstone; interbedded limier layers, becoming more distinct and more calcareous upward; prominent burrows in upper two-thirds; Taonurus in lower part; "black bed" 55 feet above base; basal bed of sandy glauconitic calcareous mudstone less cleaved than above, truncates dark gray non-calcareous mudstone of Esopus Formation.

Lunch STOP.
The Ulster County quarry (Stop No.4) borders Forsyth Park on the north. The Schoharie-Onondaga contact is located along Lucas Ave near the Park entrance and the outcrops within the Park give a section through the Edgecliff and Nedrow Members.

STOP 4. Ulster County Highway Department Quarry, Kingston
Quarry southwest of Route 209 on west side of Kingston, 0.2 mile WSW of Route 209-28 intersection. Kingston West 7.5' quadrangle, Rosendale 15' quadrangle.
This is an excellent exposure of the Nedrow and Moorehouse Members with good (and typical) fossil collecting in both units. The beds are flat lying and fossils are best observed on the extensive flat surfaces in, and at the top of, the quarry.
The section is as follows:
Moorehouse Member (upper part not exposed):
24' | Middle unit; lithology as at Leeds; brachiopods, gyroconic cephalopods and small horn corals are common; trilobites and sponges ("Hindia" sp.) are also present. .
7' | Lower unit; lithology as at Leeds; fossils are common but hard to collect in quarry face.
Nedrow Member (lower part not exposed):
8' | Moderately coarse and light-colored limestone with medium-light- gray chert; platyceratid gastropods, brachiopods, bryozoans, corals, "Hindia" sp.

STOP 5. Abandoned Quarry in Wawarsing
Small quarry north of Route 209, 0.5 mile northeast of Vernooy Kill Road, Kerhonkson 7.5' quadrangle, Slide Mountain 15' quadrangle.
Between Kingston and Wawarsing the lower part of the Onondaga becomes darker and finer grained. The characteristic Nedrow platyceratids are not present and the member cannot be recognized. The Edgecliff is marked by characteristic large crinoid columnals but is otherwise hard to distinguish from the superjacent Moorehouse Member.
The section is as follows:
Moorehouse Member (upper part not exposed):
29' | Medium-dark-gray limestone in beds 2 to 10 inches thick, some shaly beds in upper part; trilobite fragments; 2-inch chert bed at base.
20.5' | Limestone similar to above; Levenia lenticularis, brachiopod fragments and apparent juveniles are common; trilobite fragments, gyroconic cephalopod, small horn corals.
Edgecliff Member:
13' | Medium-gray, medium-fine-grained limestone with scattered chert nodules in the lower-middle part; large crinoid columnals and small horn corals are common; brachiopods and bryozoans are also present.
Transition to Schoharie Formation:
2-3' | Brown-weathering siliceous limestone forms the lowest beds in the quarry.

STOP 6. Trilobite Mountain
On northwest facing hill between two roads and the Erie R.R. near Port Jervis Golf Club, 1.1 miles northeast of Tristates, Port Jervis South 7.5' quadrangle, Port Jervis 15' quadrangle.
Cuts along both sides of road.
Only the lower few feet of the Edgecliff Member are exposed here on the northwest side of the hill, facing the Country Club. The beds are lithologically and faunally similar to the Wawarsing exposures and to the Stroudsburg outcrops farther south. Corals, brachiopods, and the large crinoid columnals are fairly common and make up most of the fauna. The Schoharie Formation is exposed between the Edgecliff face and the Erie railroad tracks. There are a few large unexposed intervals. Thicknesses, based on dip and slope measurements, are approximate.
8' | Unexposed up to the Onondaga Limestone.
Saugerties or Aquetuck Member:
25' | Yellowish-gray and yellowish-brown weathering muddy limestone containing vague layers of nodules of purer limestone.
21' | Unexposed (concealed by road).
Carlisle Center Member:
12' | exposed
25' | unexposed
24' | exposed | Olive-gray weathering dark gray calcareous mudstone; interbedded lighter weathering limier layers; a few distinct limestone beds in upper part; traces of burrows (p. ll)
70' | unexposed
41' | exposed
30' | Concealed by railroad tracks down to dark gray mudstone of Esopus Formation.

STOP 7. Tristates Point
(Not visited on the 1962 trip, but in the Guidebook.) Delaware River shore near Tristates Point in Laurel Grove Cemetery just west of Tristates, Port Jervis South 7.5' quadrangle, Port Jervis 15' quadrangle. An estimated 25 feet of dark-gray limestone is exposed on the west side of the cemetery. The rock is part of the Moorehouse Member but its exact stratigraphic position is unknown. Corals, small gastropods, and trilobite fragments are fairly common.

B: GEOLOGY OF THE PRECAMBRIAN CRYSTALLINE ROCKS, CAMBRO-ORDOVICIAN SEDIMENTS, AND DIKES OF THE SOUTHERN PART OF THE MONROE QUADRANGLE
By H. W. Jaffe and E. B. Jaffe The area covered by this trip lies in the southern part of the Monroe 7.5' quadrangle, and consists chiefly of Precambrian crystalline rocks of the Hudson Highlands. The crystalline prong is thrust at a high angle to the west over Ordovician and Devonian sediments of the northern extension of the Green Pond syncline. The fault trough is filled with lakes and glacial deposits. To the east, a high-angle fault running roughly parallel to Route 17 and continued through Tuxedo Lake to the south separates the block from the main body of the Ramapo Mountains., A small inlier of Wappinger dolomite, possible downthrown, extends nearly a mile into this fault trough, which also is covered by glacial deposits. The northern end of the block is unconformably overlain by Poughquag quartzite(Lower Cambrian) succeeded by Wappinger dolomite (Cambro-Ordovician); both dipping gently off and roughly paralleling the present outcrop pattern of the crystalline rocks. This may represent original sedimentary onlap with subsequent gentle warping during uplift of the crystalline block. This northern contact of the crystallines, and also some probable fault zones within the crystalline block, are obscured by glacial deposits which form a school of drumlins and drumlinoid hills, trending north to northwest across the regional strike of the crystallines and indicating glacial movement to the southeast. This is further corroborated by the thick glacial deposits on the east side of the northeast-southwest valleys. Within the crystalline block, strikes and dips of the foliated gneisses indicate a series of folds trending about N 50°E and plunging very gently to the north, with some local warping indicated by south plunges. A generalized cross-section normal to the foliation might show: 1) a steep syncline overturned to the west in the easternmost belt of hornblende granite gneiss; 2) an isoclinally-folded recumbent anticline, possibly thrust to the west, in the belt east of Lake Mombasha; 3) a steep syncline, again overturned to the west, with an axis just west of the west shore of Lake Mombasha; and 4) a steep isoclinal anticline along the last ridge at the west of the block. This generalized picture is very difficult to corroborate in detail because of the complexity of the folding, the large amounts of glacial fill at crucial contacts, and the considerable amounts of faulting. At least two series of faults may be recognized in addition to the aforementioned border faults to the east and west. The oldest group (not shown on the map), trending roughly N-S at a small angle to the foliation and dipping steeply, can be recognized by the small steep trenches they form, and at times by considerable silicification and skarn formation along their trend. They may have influenced the location of the frequent small magnetite deposits. This older series is offset by a set of high angle gravity faults roughly normal to the foliation. Field and petrographic evidence indicates that these may be hinge or pivot faults, with the greatest displacement to the west. Vertical or steeply dipping transverse joints strike northwest, and several of these are filled with melano and leucophyr dikes, which also cut the Poughquag quartzite and Wappinger dolomite. A subordinate set of joints strikes northeast parallel to the gneissic foliation. A description of the rock types is given in the detailed itinerary which follows. Speaking very broadly, a series of calcareous and siliceous sediments and basic volcanics of the flysch facies were folded in a eugeosyncline and wholly recrystallized with attendant modification by granitic fluids. Were these liquids derived by magmatic fractionation from a basaltic substratum, or by fractional melting of sediments in place, say 10-20 km down? Evidence for temperatures high enough to melt granitic rocks is found throughout the minerals of the crystalline block. For example, microperthites were probably homogeneous at temperatures above 640°C below which they unmix. Further, the oxygen isotope thermometer gives a temperature range of 320-550°C for staurolite zone minerals and at least a part of this area is in the higher grade sillimanite zone. Almost all of the granitic rocks show concordant relations with the paragneisses. This leaves syntectonic magmatic intrusion or in-place fractional melting as the two most probable means of deriving the granitic rocks and migmatites. In either case, the granitic rocks would have passed through a magmatic stage. The persistence of shredded and partially ingested metasedimentary remnants in most of the granitic-quartz dioritic gneisses of the area would tend to favor an in-place fractional melting hypothesis. The age of the granitic rocks and associated gneisses is believed to be about 1100 million years, based upon the best evidence from radioactive dating. Pb/U isotope ages on zircon from the Storm King granite are essentially concordant at 1100 M. Y. [discordant Pb/U ages on uraninite and monazite in the Highlands, A/K ages on mica, and Pb/α ages on zircon range from 620-900 M.Y. A recent Pb/α age of 770 M.Y. was obtained on zircon from granite interlayered with amphibolite near the Suffern entrance to the N.Y. Thruway. All of the ages below 1100 M.Y. do not necessarily date a true recrystallization. For example, a metamorphism 300 M.Y. ago might cause, 1100 M.Y old zircon to lose enough of its lead to give an age of about 770 M.Y. The absence of any ages of 200 to 400 M.Y. on minerals from the Highlands, however, indicates that the Precambrian .... rocks were not completely recrystallized during the Acadian or Appalachian orogenies.

B: GEOLOGY OF THE PRECAMBRIAN CRYSTALLINE ROCKS, CAMBRO-ORDOVICIAN SEDIMENTS, AND DIKES OF THE SOUTHERN PART OF THE MONROE QUADRANGLE

Wappinger dolomite and drumlin
At 2.0 miles observe gently dipping Wappinger dolomite outcropping in field on west side of Orange Turnpike, and large drumlin directly ahead to the, southeast.

STOP 1.
Walk 0.16 miles due west over hilltop to edge of cliff formed by 10' section of Poughquag formation (Lower Cambrian). The section consists of alternating 2" to 2' thick beds of ferruginous quartzite, conglomerate, and arkose, striking N 50°W and dipping 8°NE. Return to top of ridge and note 5.5' basic dike intrusive into Poughquag quartzite. Continuing east along hilltop note small outcrops of Poughquag quartzite and Wappinger dolomite on eath side of concealed contact. Continuing east, stop at 10' thick basic dike on northeast edge of hill. The dike strikes N 18° W and is essentially vertical; it shows flow layering parallel to the strike, and chilled borders. The modal composition of this dike is:
| 1 | 2
dark red-brown alkalic hornblende | 46.5 | 37.0
augite-pigeonite | 6.0 | 13.1
chlorite | 8.4 | 9.0
prehnite | 0.2 | --
calcite | 0.3 | --
(calculated SiO2 content: 44-46%)
The texture is seriate-porphyritic with hornblende and augite forming the phenocrysts, which lie in a groundmass of albite laths.
This rock is a melanophyr, here defined as a dark, dense, fine-grained, porphyritic dike in which only the mafic minerals form phenocrysts. The abundance of the alkali-rich red-brown hornblende and the low calculated silica content indicate that this dike is compositionally related to the undersaturated alkalic rocks (camptonite lamprophyre of Johanssen). It is not a diabase or a "basaltic dike" but a true alkalic rock. This dike and two others in the area intrude the Wappinger dolomite and are here considered to be of post-Ordovician age. Similar dikes are found in the Adirondacks in close association with true diabases and in the Champlain Valley without the accompanying diabases. The Champlain Valley dikes are clearly post-Ordovician with the upper age-limit unknown. The melanophyr dikes in the southern and central part of the Monroe quadrangle are numerous; they intrude the crystalline rocks and Cambro-Ordovician Poughquag-Wappinger series; but none have yet been found cutting the immediately adjoining thick section of Devonian sediments in the same small quadrangle. This would suggest that the dikes are older than the Triassic diabase sequence. Further evidence suggesting a pre-Triassic age is the presence of garnet and abundant epidote presumably formed during a pre-Triassic orogeny. Inasmuch as albite should not be expected in a rock containing 75% of mafic minerals, the epidote may be assumed to have unmixed from an originally more calcic plagioclase during a regional metamorphism. In thin-section most of the epidote is included in the albite laths. Return east to the road and observe outcrop of blue-gray Poughquag arkose or feldspathic quartzite. This rock consists of 1-3 mm subrounded strained detrital quartz, microcline-microperthite, and minor oligoclase in a finer-grained quartzo-feldspathic-clay-sericite-"limonite" matrix. The principal cement is authigenic quartz overgrown in optical continuity on detrital quartz. The absence of rock fragments and the low interstitial paste content indicates that the rock is not a graywacke. Minor amounts of zircon, sphene, brown tourmaline, anatase, and opaques are present. The abundance of microcline microperthite and quartz suggests that the rock was derived from the adjoining Precambrian granitic gneisses.

STOP 2.
Leaving Stop 1, the Orange Turnpike turns southwest and crosses the concealed unconformable Cambrian-Precambrian contact. Beyond the Lipalian interval, the first Precambrian rock encountered is a fine-grained pink alaskite with no more than 1% of dark minerals. It is composed mainly of 1-3 mm microcline microperthite, microcline, and quartz, with much less sericitized albite-oligoclase and an occasional flake of biotite or chlorite. Within 100' to the south, the pink alaskite grades through a narrow zone of coarse biotite microperthite oligoclase granite and granodiorite into a medium-grained, gray, essentially massive quartz diorite gneiss which forms the bulk of the southern outcrop at this stop. The quartz diorite gneiss (quartz oligoclase gneiss of other workers) consists of oligoclase antiperthite about 70%, quartz about 25% and hypersthene, biotite, magnetite, chlorite about 5%. In thin-section, quartz is not uniformly distributed and forms long tongues which embay adjoining oligoclase grains. Oligoclase is well-twinned and antiperthitic. On top of the outcrop, observe several tongues of biotite hornblende hypersthene labradorite (An55) pyribolite infolded in the quartz diorite gneiss. Foliation measured on the pyribolite is N35° -50°E, dip is essentially vertical. Slickensided joint faces strike N 24°W and N 65°W. About 0.3 miles south (not a scheduled stop) the quartz diorite gneiss darkens in color, the quartz content drops and the rock grades to an augite diorite gneiss with abundant interlayered hornblende hypersthene oligoclase-andesine pyribolite. Where quartz becomes locally abundant, it embays and replaces both plagioclase and the ferromagnesian minerals.
The quartz diorite gneiss is thus formed from the reconstitution of pyribolite accompanied by the introduction of silica and small amounts of potash. These constituents could logically be derived from granitic liquids formed from the fractional melting of sediments.

STOP 3.
Turn east on Harriman Heights Road. A fresh road-cut exposes a dark gray and pink banded migmatite. The gray rock is a calcarious siliceous paragneiss composed of quartz, microcline, bytownite (An80, nγ = 1.575), augite, epidote, dark brown sphene, zircon, apatite, and magnetite. The pink bands consist mainly of quartz and microcline or microcline microperthite. Other samples of this migmatite carry anorthite with An95 (nα = 1.574, nε = 1.581 nγ = 1.585, 2V-≡ 75° , opt. -). This migmatite carries abundant epidote produced by a retrograde metamorphic alteration of anorthite and augite.

Return west to Orange Turnpike and turn south, parking at Monroe Town Line sign. The prominent road-cut on the east side of the road is gray and pink banded biotite migmatite. The dark gray rock is a siliceous, calcareous paragneiss composed of quartz, labradorite (An50), biotite, microcline, hornblende, epidote, apatite, zircon, augite, and ilmenite. The pink bands consist wholly of quartz and microcline, the latter occasionally microperthitic. These kalialaskite bands are believed to be formed from low-temperature metasomatic introduction of quartz and microcline. In-place melting would require an appreciable amount of albite, which is not present. As the microcline is only occasionally microperthitic, it is doubtful that it could hold much soda in solid solution. The foliation strikes N 24°E and dips 45°SE; fold axes plunge gently NE.
The outcrop on the west side of the road, just south of the Town Line, is the same rock. Here the foliation strikes N 22 E, dips only 12°SE and fold axes plunge 5°NE. The gentle dip is due to isoclinal folding overturned to the west.

Continue south on Orange Turnpike to top of hill with prominent overhanging cliff to the east aide of the road. The cliff is made up of a silicified epidotized migmatite with some coarse recrystallized hornblendes in the granitic component. The outcrop is strongly warped, part of it showing recumbent isoclinal folding overturned west, part of it showing fairly steep dips east. The undersides of overhanging bedding planes are commonly slickensided and silicified. Both this outcrop and the one immediately preceding it suggest an old period of thrusting to the west.

Continue south to the junction with the second of two roads entering from the west. Outcrop on the west side of the road shows a 20-25' hornblende albite melanophyr (spessartite) dike which strikes N 38°W, dips 86°NE, and cuts across the foliation of the granite gneiss which strikes N 55-75°E and dips 80°SE. The dike shows normal green hornblende phenocrysts up to 0.25" lying in a matrix of albite laths, 0.2 x 0.4 mm. The modal composition of the dike is:
albite | 53.3
hornblende | 21.5
epidote | 12.6
chlorite | 7.3
apatite | 0.1
opaque | 3.2
quartz | 1.2
calcite | .4
K-spar | .4
| 100%
(calculated SiO2 content = 53.5%)
The granite gneiss contains occasional schlieren of biotite-rich gneiss.

The road parallels the contact of granite gneiss (east) and pyribolite (west). At 8.4 miles the road crosses this contact. Stop 7 shows a 16' thick granodiorite leucophyr dike which strikes N 48°W, cross-cutting the foliation of the surrounding amphibolite which strikes N 57°E and dips 20° SE. Note large wedge of amphibolite in center of dike and occasional pink potash-feldspar-quartz bands in the amphibolite. This dike is unique in this quadrangle and perhaps in the Highlands. It is composed of sparse phenocrysts of oligoclase, quartz, less microcline, and rare biotite, lying in a matrix which is again porphyritic on a microscopic scale. The second generation of micro-phenocrysts is made up of square to rhombic zoned potash feldspar and laths of albite-oligoclase. These lie in a very fine granophyric groundmass made up of feldspar, quartz, mica, chlorite, and "limonite." The "limonite" forms megascopic crenulated black streaks which give the dike a flow layering in places. A mode was not obtained because of the fine-grained nature of the groundmass. X-ray data on a powdered sample indicate that oligoclase >quartz > microcline, hence the dike is of granodioritic composition. East of the road the dike is not found, and may be cut off by a north-south fault; if this is so the dike is very old. An outcrop of the same type of rock was found 0.25 miles to the west cutting migmatite: this may be an extension of the same dike.

Continue north on East Mombasha Road stopping at steep cliff on east side of road. This is a fine-banded dark gray and pink biotite migmatitic paragneiss, the fine-bedded analogue of stop 4. The dark gneiss bands here are more altered and are marked by the appearance of muscovite and epidote replacing biotite and plagioclase. A small amount of rutile is formed from the titanium present in biotite. Occasional large pods of pink alaskite are concordantly interleaved in the migmatite. The foliation strikes N 37°E and dips 20°SE.

STOP 8A.
Continue north on East Mombasha Road stopping at the sillimanite-bearing outcrop just north of number 8A on the map. This is a tightly folded, crenulated biotitic. paragneiss in the sillimanite zone of metamorphism. It is composed of thin bands of a gray biotite microcline labradorite quartz paragneiss interlayered with orthoclase cryptoperthite (anorthoclase) quartz bands. Abundant garnet (almandite-pyrope), dark blue-green tourmaline, and minor prismatic sillimanite are developed at the interfaces of the biotitic and alaskitic layers. The biotite is pleochroic from "paprika-red" to almost colorless and is an iron-rich variety. Sillimanite and tourmaline lie in the foliation planes with their long axes parallel to the fold axes. The fine paragneiss bands have an average grain size of 0.3 mm, the coarse alaskitic bands, up to 10 mm.

Continue north on East Mombasha Road to sharp bend north after short jog east. Outcrop on east side of road contains abundant garnet in biotite migmatitic paragneiss. Outcrop to the west in an open field, near swamp, shows a biotite migmatitic paragneiss and pyribolite intimately folded in medium to coarse massive alaskite. The alaskite forms the core of a fold plunging north and the outcrop may be a small anticline overturned to the west. Here chloritized amphibolite pods are completely enclosed in alaskite. A thin section of the dark gneissic rock showed completely fresh hypersthene: (normally an unstable mineral) and biotite associated with completely scapolitized plagioclase, and quartz. Garnet occurs sparingly. To the west the rocks grade rapidly to almost pure alaskite. This is the northernmost outcrop of garnet migmatite.

Continue northeast on East Mombasha Road to bottom of hill at rough track to the west. On the east side of the road is an outcrop of coarse, gneissic, partly recrystallized amphibolite. It contains plagioclase ranging from andesine to bytownite with abundant hypersthene, brown and green hornblende, and less biotite, the composition varying with layering. To the east in the woods (not visited) the plagioclase is all scapolitized, the hypersthene serpentinized, and a pale blue-green hastingsite or edenite amphibole is developed near the contact with the alaskite of stop 2. On the west side of the road, about 60' in the woods, a thin layer of foliated green hypersthene quartz oligoclase gneiss (quartz diorite gneiss) is in sharp contact with fine-grained pink alaskite. This may be a fault contact. Boulders of Poughquag conglomerate, and a melanophyr dike (camptonite), parallel the contact zone.

Note NW-trending drumlins to the west.

Continue NE to Orange Turnpike, then NW past stop 1 to Rye Hill Road. Turn sharply SW, noting NW-trending drumlins to the west. Stop 11 is the first outcrop beyond the glacial fill on the east side of the road, which now is called Berry Road. The outcrop contains abundant layers and schlieren of biotite two-feldspar quartz paragneiss in coarse pink granodiorite and granite with abundant antiperthite, microperthite, and oligoclase. A swarm of eight or ten small melanophyr (camptonite) dikes, up to 2' thick, fill a tension fracture pattern striking N 8 W to N 48°W. The foliation of the host granitic rock strikes N 52°E, and dips 50-60°SE. To the west, in the woods; the biotitic paragneiss is resorbed by massive biotite granite-granodiorite. Occasional samples are of quartz syenite composition.
It is worth noting here that melting of biotite would yield an additional large amount of potash feldspar and magnetite:
KFe2AlSi3O10(OH)2 --> KAlSi3O8 + Fe3O4
biotite ---- > K-feldspar + magnetite
This would sweeten the granitic liquid and perhaps explain the frequent occurrence of potash-feldspar pegmatites in association with the many small magnetite deposits of the area. It should further be noted that many of the alaskites in the quadrangle contain magnetite as the only accessory mineral of consequence.

Continue SW on Berry Road, noting alternation of folded dark gneiss and pink granite-granodiorite; turn NW on West Mombasha Road, then NE on Cedar Cliff Road to stop 12, about 200' beyond farmhouse. Outcrop on east side of road shows fine-grained narrow bands of folded pyribolite (here amphibolite) overturned slightly to the west and being replaced by coarse massive buff-gray granodiorite. The granodiorite cuts across the folded amphibolite and contains schlieren of the latter which retain their original attitude in the folds. The infolded amphibolite contains brown hornblende, albite-oligoclase, microperthite (introduced), biotite, magnetite, and apatite. The granodiorite is composed of albite-oligoclase, quartz, less microcline microperthite, biotite, hornblende, zircon, and some fragments of altered hornblende, plagioclase, and calcite. Pyribolite layers are very abundant in this zone but are not continuous, the widest observed being 80' thick near the old magnetite mine on Mine Road. Westward the rocks grade to contaminated gneisses and then alaskite, which forms the western edge of the crystalline block.

C: THE STRUCTURE AND STRATIGRAPHY OF THE PORT JERVIS SOUTH-OTISVILLE QUADRANGLES
Co-authors:
Sidney Fink, Dept. of Geology, Brooklyn College
C. J. Schuberth, The American Museum of Natural History
The area of this field trip, Port Jervis South-Otisville Quadrangles, (Fig. 1) includes parts of the Folded Appalachian Mountain, Great Valley and the Appalachian Plateau geomorphic provinces. The Paleozoic formations, deposited originally as horizontal sediments in an extensive geosyncline, have in this area an aggregate thickness in excess of 5,000' and consist of the following units, in ascending order: Martinsburg Graywacke Shale and Sandstone (Middle (?) and Upper Ordovician), Shawangunk Conglomerate (Lower to Middle Silurian), High Falls Red Beds (Middle to Upper Silurian), Poxono Island Shale, Bossardville Limestone and Keyser Group (Upper Silurian), Helderberg and Oriskany Groups, Esopus Shale and Onondaga Limestone (Lower Devonian), and the Hamilton Group (Middle Devonian). Quaternary glacial drift and till occurs throughout the area (Pl. 1).

C: THE STRUCTURE AND STRATIGRAPHY OF THE PORT JERVIS SOUTH-OTISVILLE QUADRANGLES

Roadcut through kame (at sharp turn).

Esopus Fm.
Outcrop of Esopus Formation (along right side of road); well-developed southeast slaty cleavage.

Base of Appalachian Front on left (NW)
Traveling along base of Appalachian Front on left (NW). The lowland is underlain by the Onondaga Limestone which is hidden by a cover of till.

Helderberg Ridge
Helderberg Ridge (lower Devonian) on right (SE); dip-slope of Kittatinny (Shawangunk) Mountain farther east.

Marcellus Shale
Marcellus Shale dipping gently NW (into Appalachian Front) at left (NW). Overlying these black fossiliferous shales are the olive-gray graywacke shales and sandstones of the Hamilton. group. These represent the sediments derived from source areas to the east at the onset of the Acadian Orogeny.

Unsorted and unstratified glacial till

Crossing Neversink Valley covered with glacial till

Entering Helderberg Ridge

STOP 1. Esopus Formation.
The rocks exposed along the road are the black shales of the Esopus Formation. This formation is characterized by its well-developed southeast dipping slaty cleavage. The normal north-west dip of these lower Devonian beds is obscured due to the cleavage. The Esopus is the most important formation in the ridge west of Shawangunk Mountain (Pl. 5, Fig. 1). At the crest of this ridge is the Glenerie Cherty Limestone. The Glenerie is a limestone facie of the Oriskany Sandstone. In the valley between this ridge and Shawangunk Mountain to the east is found the limestones of the Helderberg Group (Pl. 5, Fig. 2).

STOP 2. Martinsurg / Shawangunk contact
Unconformable contact between Martinsburg Shale and Shawanqunk Conglomerate (walk approx. 300 feet east along railroad tracks).
In this railroad cut is exposed an angular unconformity between the Martinsburg and Shawangunk Formations. The Martinsburg dips 37°NW and the overlying Shawangunk dips 28°NW. The Martinsburg is made of interbedded graywacke shales and sandstones. The Shawangunk is a massive quartz sandstone with a 40-50 foot basal quartz conglomerate. The high percentage of quartz, the well rounded grains, the high index of sorting, and the great thickness, all characterize a beach deposit developed over a long period of time. In an old quarry above the road, Schuchert (1916) found Eurypterids in the shale beds found within the Shawangunk. In places the Shawangunk is cut by quartz-filled veins that are mineralized with pyrite, chalcopyrite, galena and sphalerite. These veins near Guymard (3.5 miles southwest of this locality) were the site of a small lead-zinc industry approximately 75 years ago.

STOP 3: Small quarry in New Scotland Formation.
The beds exposed in this cut are those of the Lower Devonian New Scotland Formation. Most of the formation consists of dark blue black shaly limestones. Toward the base of the formation abundant chert is found. The chert layers represent the Kalkberg Member of the New Scotland. The non-cherty beds are characterized by the following fauna:
Spirifer maclopleura
Leptaena rhomboidalis

STOP 4. Recumbent fold in Martinsburg
Recumbent fold in Martinsburg (east side of Erie Railroad tunnel) - walk approx. 500 feet along railroad track.
On the north side of the track, the Martinsburg has been folded into a recumbent fold. In the same locality other signs of deformation are seen, (1) overturned beds, (2)small scale fault east of the recumbent fold. Although folding and faulting are seen in the area, metamorphism of the shales is not evident. It is interesting to note that the Shawangunk-Martinsburg contact is found near the crest of Shawangunk Mountain and not near the base. This is due to the predominance of sandstone beds that are quite massive in the upper part of the Martinsburg. The valley east of Shawangunk Mountain is part of the Great Valley and is underlain in this area by the Martinsburg Formation.

Martinsburg on right (W).

Exposure of Martinsburg on right (W).

STOP 5. Martinsburg Formation.
Cyclic repetition of graywacke sandstone (with some layers becoming quite heavily bedded) and black, fissile shale characterizes the lithology of the upper portion of the Martinsburg, the oldest formation in this area (Upper Ordovician). Massive graywacke, several feet in thickness, quite prevalent near the top of the Martinsburg section (striking northeast and dipping on the average of 30 northwest), partially supports Kittatinny Mountain. The contact between this formation and the overlying Shawangunk Conglomerate, nowhere exposed in this area, lies just below the topographic crest of this ridge. Irregularities in sedimentation (seen readily in other exposures along the strike) are represented by irregularly-shaped fragments of shale within the massive graywacke layers. These isolated pieces are lenticular and the subjacent beds show no gaps, into which they might fit. Other fragments are concave and sharply angular at their ends and appear torn from their position by slight tectonic movements. Undoubtedly, irregularities in primary sedimentation or slumping or other settling movements, incidental to primary deposition but taking place after sufficient hardening of the deformed layers, permitted them to act as competent units. Van Houten (1954) proposed that Martinsburg mud accumulated slowly in a marine environment. Sand, periodically stirred up in the shallow sea was carried to deeper water environments by spasmodic turbidity currents, and as the velocity decreased, the unsorted sediments settled in graded' beds (not a prominent feature in the sandstone because no great range in grain size is involved in vertical sorting). These deposits may represent a "poured in" type of sediment, derived from the rapid erosion of tectonic source areas.

STOP 6: Exposure of Shawangunk Conglomerate.
This is near the nose of a doubly plunging syncline of this formation. (See Pl. 6 and accompanying discussion.)
Lake Marcia on left (W) underlain by strongly sheared Martinsburg Shale. The "scenic drive" parallels the strike of the western limb of the syncline; dips range from, 30° to 70° southeast.

STOP 7. Highest elevation in New Jersey. 1,803 feet a.s.l.
This is the highest point in New Jersey. We are still on the western limb of the plunging syncline. Note the steep south-east dips (60°SE). Lake Marcia is located in the Martinsburg Shale as a result of breaching of the anticline immediately to the west and erosion along a thrust fault. The anticlinal, unbreached structure continues southwest (southwest of the A.T.&T. tower) until it ultimately dies out (in the southwestern portion of the Port Jervis South Quadrangle). All structures are doubly plunging. Toward the west lies the Pocono Plateau and along the east, the Great Valley underlain by the Martinsburg Formation.

D: STRATIGRAPHY AND STRUCTURE OF THE "CATSKILL GROUP" IN SOUTHEASTERN NEW YORK
Frank W. Fletcher
The University of Rochester
"A blackboard drawing or a textbook illustration of a sedimentary facies has quite a different appearance from a sedimentary facies when one encounters it in the field. In the field, facies changes seem baffling and bewildering, especially in an area of new and unknown stratigraphy. It is as if stratigraphy, hitherto subject to natural laws and capable of rational analysis, had suddenly gone lawless and planless." P. B. King
THE CATSKILL PROBLEM
Within the Devonian rocks of southeastern New York there are approximately 5000 feet of interbedded red and gray sandstones, shales and conglomerates known collectively as "Catskill." After more than a century of investigation, virtually the only conclusions agreed upon by the various workers in the area are that the facies changes are complex, the location of formation boundaries is difficult, few fossils are present, correlation is uncertain, and the sedimentary environment is either subaerial or subaqueous.

D: STRATIGRAPHY AND STRUCTURE OF THE "CATSKILL GROUP" IN SOUTHEASTERN NEW YORK

Point Peter, Port Jervis, N. Y.
Outcrop of dark gray shales and sandstones called Portage by Willard (1936) and marine Devonian beds on the Geologic Map of Pennsylvania. These rocks contain many of the same fauna as the Mount Marion Formation along the Catskill Front.

Hawks Nest formation
Beginning of outcrop which shows the type section of the Hawks Nest Formation.

STOP 1. Type section of Hawks Nest Formation.
The name "Delaware River Flags" was first applied by I.C. White in 1882 to the rocks which overlie the marine Hamilton (?) beds just north of Port Jervis, New York. He reported a thickness of approximately 1400 feet. Willard(1936) redefined the formation as 1500 feet of greenish flags without red beds. He states that the formation is correlative with the Onteora Formation of the Catskill front. However, he fails to give an adequate reason for the disappearance of almost 3000 feet of red strata (the combined thickness of the Onteora and pre-Onteora red beds) which is necessary to support such a correlation. Examination of rock samples from exploratory oil and gas wells in the area has shown that a thick sequence of red strata occurs in the upper 700 feet of Willard's Delaware River Flags. This sequence of red beds can be traced, in a series of wells, north along the Delaware River and into the region of Oneonta, New York, where it is called the Oneonta Formation. This has prompted Fletcher to discard the name Delaware River Flags. The section of gray sandstones and shales which, in southeastern New York, lie beneath the Oneonta Formation, are defined as the Hawks Nest Formation after the excellent exposures on the high cliffs at Hawks Nest, N.Y. This 800 foot sequence of strata is probably correlative with the Unadilla Sandstone of the Oneonta region. The dominant lithology is a fine- to medium-grained, light to medium bluish gray subgraywacke. The fine-grained sandstones are finely laminated and flow rolls are common. The medium-grained sandstones exhibit low angle cross-bedding. A limonite stain is present on the weathered rock surface. Interbedded with the sandstones are medium dark gray to grayish blue siltstones which are brownish gray on weathered surface and lack fissility. The formation is generally unfossiliferous.

3.1 miles from Point Eddy bridge
4.56 miles between Point Eddy bridge and Mongaup bridge

Outcrop at left along the river.
Outcrop at left along the river. A clear expression of the regional dip, cross-bedding, and joint pattern.

Large quarry at the right.

STOP 2. Outcrop of the Oneonta Formation.
In the same report in which Mather defined the Catskill Mountain Group, L. Vanuxem (1840) proposed the name "Montrose sandstone or sandstone of Oneonta" for the red and gray rocks found in Otega, Broome and Chenango counties, New York. The Geologic Map of New York shows these 700 feet of strata correlated with the Onteora Formation. Fletcher, however, has suggested an alternative correlation (see Plate IV). Stratigraphic columns constructed from samples from gas wells located in the northeastern Catskill Mountains show that only the lower 800 feet of Chadwick's Kiskatom red beds "drop out" before they reach the type section of the Oneonta Formation. Beneath the Twilight Park Conglomerate is a 900- foot zone of predominantly red strata, 250 feet of dark gray shale and sandstone with two thin beds of coarse-grained, white quartzose sandstone,and about 800 feet of intercalated red and dark bluish gray sandstone and shale. The 250 feet of rock containing the two thin white sandstone beds forms a distinctive and persistent marker horizon in subsurface samples. This zone has been traced to the Durham quadrangle where it was called by G.A. Cooper (1934) the eastern equivalent of the Portland Point Member of the Moscow Formation. In the Durham quadrangle the zone is underlain by 350 feet of red beds. In the Margaretville quadrangle, west of the Catskill front, only 100 feet of red beds underlie the white sandstone units. At the type locality of the Oneonta Formation this zone is located approximately 900 feet beneath the lowest red bed. As a result of these findings the strata Chadwick called Kiskatom have been 'divided into three units. The lower red zone, which loses its red beds rapidly to the west and south, is designated the Plattekill Formation and its type section is taken as Plattekill Clove. The middle zone is called the Potter Hollow Formation after Potter Hollow, Greene County, New York. The upper red zone is the Oneonta Formation. The Oneonta contains micaceous, pale red purple and grayish purple siltstones and mudstones. The red mudstones exhibit slickensides formed by slumping of unconsolidated mud before induration. The sandstones are medium grained, red purple and light gray to greenish gray subgraywackes. They weather light greenish gray. The flaggy sandstones have primary current lineations on bedding surfaces and, with the exception of one type of freshwater (?) pelecypod and plant fragments, are unfossiliferous.

Sandstone outcrop along railroad on Pa. side of river.

Sandstone outcrop
Sandstone outcrop on right side of highway. Notice well-expressed joint sets. Red siltstone at top of hill.

Outcrop along railroad on Pa. side.

Outcrop of sandstone
Outcrop of sandstone on right side of highway. Cross-stratification is absent. Red siltstone near bottom of hill.

Red mudstone indicates regional dip
Outcrop on right. Watch for appearance of red mudstone which indicates the regional dip.

Large outcrop of the sandstone on the right.

Cross-stratification.
Outcrop showing well-developed cross-stratification.

Red siltstone and dark gray shale
Outcrop on both sides of the highway. Red siltstone and a dark gray shale are exposed.

Barryville member of the Shohola Fm.
Outcrop of the Barryville member of the Shohola Formation (see Willard, 1936). Notice the distinctive weathering "holes."

Cross ten mile river

Cross-stratification.
Sandstone outcrop at left showing well-developed cross-stratification.

Outcrop near the top of the sandstone on the right side of the highway.

Outcrop at right. Notice the abundance of red soil.

Red siltstone exposure at right.

Red siltstone with anticlinal structure
Outcrop of red siltstone and mudstone on right side of highway. Notice anticlinal structure.

STOP 3. Type locality of the Damascus Formation.
Above the Stony Clove Formation in the Delaware River region are about 400 feet of strata composed almost entirely of red sandstone, siltstone, mudstone and shale. Willard (1936) gave the name Damascus Formation to these rocks after Damascus, Pennsylvania where this sequence is well exposed. These strata were originally named "Montrose" by White (1882) who believed they were the same red beds which crop out around Montrose, Pennsylvania. Fletcher has correlated the Damascus with the basal portion of the Katsberg formation, called Lower Katsberg on the Geologic Map of New York State. At the type locality the formation lies in the center of a large syncline (see section on structure), so that along the Delaware River older beds occur both to the south and north of the outcrop of the Damascus Formation. The sandstones are fine- to medium-grained and are grayish red purple. The few interstratified greenish gray sandstones range from medium- to coarse-grained. Both red and gray sandstones exhibit cross-stratification. The red mudstones and siltstones strongly resemble the same in the two previously described red formations; however, more of the fissile red shale is found in the Damascus Formation.

Red shale and mudstone exposed on both sides of highway.

Outcrop of gray sandstone in Damascus Fm at right.

Red sandstone exposure at right.

STOP 4. Outcrop of the Lower Katsberg Formation.

E: THE FRANKLIN STERLING MINERAL AREA
by
Helen A. Biren, Brooklyn College
The area which we shall visit is a limestone region lying in the New Jersey Highlands, which is part of the Reading Prong. It extends in a northeasterly direction across the northern part of the state. The rocks are Precambrian "crystallines" with narrow belts of infolded and infaulted Paleozoic sedimentary rocks. Major' longitudinal faults slice the fold structures, so that the area has been described as 'a series of fault blocks extending from south of the Sterling Mine to Big Island, N. Y."
For many years the Franklin Limestone yielded enough zinc to make New Jersey a leading producer of this commodity. Mining has steadily decreased in this area, and in 1955 the Franklin Mine was shut down permanently, so that mineral specimens are derived mainly from surface dumps and quarries. Some twenty million tons of ore were removed from Franklin before it was shut down.

STOP 1. Sterling Hill
The Lord Sterling Pits, the earliest known workings (1770) outcropped in the legs of a syncline in the Franklin Limestone, which pitches northeast at an angle of about 50° from the horizontal. Details of the structure are quite complex. About 1913 a shaft was sunk and extensive underground development started. The ore appears to have followed definite stratigraphic horizons in the folded structure, since the banding of the Franklin Limestone and the complex folding of the ore veins appear to conform. Pegmatites are not present with the ore, so fare minerals are fewer than at Franklin. Minerals reported from this area (other than the common species listed on the chart) include: Chalcophanite, McGovernite, Mooreite, and Roepperite.

STOP 2. Farber Quarry
The Farber Quarry (formerly the Bigelow Quarry) on Cork Hill road at the Franklin-Ogdensburg line is the only active quarry. In this white limestone may be found tremolite in fluorescent crystals, pyrite crystals and calcite, chrondrodite, norbergite, magnetite, dolomite, edenite, fluorite, graphite, hematite, phlogopite and scapolite.

STOP 3. Slag boulders from Franklin Furnace
Along the east side of Cork Hill Road are large, dark boulders which represent slag from the old Franklin Furnace. Many minerals are present in some of the boulders, and the "vesicles" in the slag show a variety of fillings representing secondary mineralization.

STOP 4. B. Nicol Quarry (Formerly the Fowler Quarry)
This was the largest quarry in the area, and was active at the turn of the century as a source of flue for the blast furnace.
It is requested that visitors stay clear of the buildings of the Cellate Corporation, and do not smoke in the vicinity of the buildings or drums.
Recent visits to this quarry have yielded specimens of amphibole, apatite, arsenopyrite, chondrodite, diopside, edenite, fluorite, graphite, magnetite, phlogopite, pyrite, pyrrhotite, pyroxene, quartz, scapolite, spinel and green and brown tourmaline.

STOP 5. Furnace Quarry
This is an abandoned quarry in the white limestone which has yielded many metamorphic minerals, including arsenopyrite, edenite, fluorite, graphite, norbergite, pyrite, pyrrhotite, rose quartz, sphene, spinel and tourmaline.

STOP 6. Buckwheat Dump
In 1852 the eastern leg of the syncline was discovered, and was stripped to form the Buckwheat open cut. Much of the overburden was removed to the dump. The accompanying key lists 50 minerals which are likely to be found there. Since the town of Franklin turns the dumps over at intervals, fresh materials are exposed, so that there is a likelihood that a variety of species will be available. In the sheds at the foot of the dumps some long and short wave ultraviolet lamps will be available for determining fluorescent phenomena. Accompanying this paper is a chart describing the fluorescence of Franklin minerals, as observed and as reported in the literature. Not all samples of a given mineral will display the described fluorescence, but it is certain that Buckwheat will yield some fluorescent material.

STOP 7. Mine Replica
The mine replica is an authentic duplicate of a typical working space in the abondoned Franklin Mine, and a display of fluorescent minerals under ultra-violet light. This is an optional trip and involves a 50-cent admission charge. Since only a limited number can be accommodated at one time, arrangements for this visit will be made while the rest of the group is collecting at the vaqrious quarries.
This trip also offers a good view of the Buckwheat open cut.
2010: This is now operated as part of the Franklin Mineral Museum:
http://www.franklinmineralmuseum.com/

Geology of South-Central New York
a guidebook
with articles and field trip logs
prepared for the
Binghamton, New York
May 3-4, 1963
Donald R. Coates, Editor
HOST
Department of Geology
Harpur College
of the
State University of New York

A: UPPER DEVONIAN STRATIGRAPHY AND SEDIMENTOLOGY IN THE BINGHAMTON AREA
James E. Sorauf and Herman E. Roberson
Harpur College
No Road Log

STOP 1 Twist Run
The road cuts in Twist Run (Fig.2), expose beds of the Rhinestreet Formation. Near the top of the hill is a 7-foot interval of dark gray, fissile shale, the Dunn Hill Member of the Rhinestreet Formation. Above the Dunn Hill shales are the basal beds of the overlying Beers Hill Member of the Rhinestreet. Approximately 12 to 15 feet of strata of the Beers Hill Member are composed of siltstones, generally quite massive where fresh, but weather into thin and irregular units. The basal 4-foot unit exhibits minute crosslamination.
Below the Dunn Hill Member is the Millport Member of the Rhinestreet, comprising the largest amount of the exposed beds. It is composed of a series of units which are somewhat cyclic in nature. Ideally the unit grades from massive, very fine-grained sandstone at the base, through massive siltstones into siltstones progressively thinner bedded and more argillaceous upwards, with a thin bed of dark shale at the top. At the base of each massive unit are flow rolls. Few if any of the units show the complete range of lithologies listed above, and each unit is extremely lenticular. Thus the measured thicknesses of each bed shown on Figure 2 must be regarded as true only for the exact place of measurement. Several of the massive beds of very fine-grained sandstone can be seen pinching out laterally within the confines of the outcrop.
Faunal elements are present within the sequence, either interspersed along bedding planes within the siltstone layers, or in definite beds of coquina. Both brachiopods (orthids, productids, and spiriferids) and pelecypods are abundant at several levels. At least three thin beds of coquina are present within this sequence. At this locality, each bed is very thin; the thickest observed being less than 6 inches.
The lowest outcrops in Twist Run are still within the Millport Member, which is underlain by the basal or Moreland Member of the Rhinestreet Formation. The Moreland is a dark shale unit similar in lithology and thickness to the Dunn Hill Member seen at this locality.

STOP 2 Binghamton Brick Co. Quarry
The quarry of the Binghamton Brick Company is developed in the Millport Member of the Rhinestreet Formation. The Moreland Member is exposed at the entrance to the quarry below the level of the main floor. The quarry floor and walls, developed as a series of steps carved from the hill, are composed of beds of the Millport Member.
As in Figure 3, the Millport Member in this locality consists of a series of alternating gray to green siltstone and shale. The shale units range from 10 to 15 feet in thickness, and are generally thin-bedded and fissile, especially where weathering has occurred. Medium-bedded siltstones occur in a somewhat cyclic pattern throughout the section. In the upper part of the sequence, the siltstones are more thickly bedded, and correspondingly the cyclical pattern is not as regular.
Smooth, continuous bedding planes between shale beds and also between shale and siltstone beds predominate; there appears to be little lensing. Small-scale cross-laminations may be observed in the siltstones.
Two prominent flow roll zones may be observed. The first occurs about 100 feet above the floor of the quarry, and the next about 20 feet higher. The flow rolls of the latter unit are numerous, and range greatly in size, shape, and degree of development. Beds of coquina are seen in place and in slump in the upper part of the section.

STOP 3 Corbisello Quarry
The Corning Member of the Gardeau Formation and the overlying New Milford Formation are exposed in this quarry. The Corning Member at this localtiy is a gray, fissile shale, of which approximately 5 feet are exposed.
The New Milford Formation contains a tongue of the Catskill facies at the base. This tongue is composed of massive, interbedded, thick lenses of sandstone. Lenticular cross-lamination is present in the thick lenses. There is a thin disrupted coal seam in the middle part of this sandstone unit. Ripple marking has been preserved on the upper surface of this sandstone tongue. This is probably a fluviatile deposit deposited near the strand line of the Upper Devonian sea.
Overlying the massive sandstone is a thick sequence of shale and interbedded siltstone. These fine-grained rocks are thought to be near-shore deposits, possibly lagoonal muds. Above the unit of shale and interbedded siltstone is another sequence of massive lenses of sandstone with interbedded siltstone and shale. These beds are similar to the basal sandstone in lithology, but are extremely lenticular.
This is the only stop on this trip, or on the trip led by Woodrow and Nugent, where the Catskill non-marine facies may be observed. Several miles to the south the New Milford is entirely composed of beds belonging to the Catskill facies.

B: GEOMORPHOLOGY OF THE BINGHAMTON AREA
Donald R. Coates
54.6 miles

B: GEOMORPHOLOGY OF THE BINGHAMTON AREA

Binghamton Brick Company.
From Stop A-2 description: The quarry of the Binghamton Brick Company is developed in the Millport Member of the Rhinestreet Formation. The Moreland Member is exposed at the entrance to the quarry below the level of the main floor. The quarry floor and walls, developed as a series of steps carved from the hill, are composed of beds of the Millport Member.
As in Figure 3, the Millport Member in this locality consists of a series of alternating gray to green siltstone and shale. The shale units range from 10 to 15 feet in thickness, and are generally thin-bedded and fissile, especially where weathering has occurred. Medium-bedded siltstones occur in a somewhat cyclic pattern throughout the section. In the upper part of the sequence, the siltstones are more thickly bedded, and correspondingly the cyclical pattern is not as regular.
Smooth, continuous bedding planes between shale beds and also between shale and siltstone beds predominate; there appears to be little lensing. Small-scale cross-laminations may be observed in the siltstones.
Two prominent flow roll zones may be observed. The first occurs about 100 feet above the floor of the quarry, and the next about 20 feet higher. The flow rolls of the latter unit are numerous, and range greatly in size, shape, and degree of development. Beds of coquina are seen in place and in slump in the upper part of the section.

Phelps Creek and south side of Hillcrest.
Phelps Creek and south side of Hillcrest. Cemented gravels attest to high lime content of sediments. This kame terrace with 900' level extends along east side of road 1.5 miles

STOP 1
Valley train outwash plastered on bedrock of shale and siltstone to height of 140'. Strata are in contact between Upper Sonyea Group at the base and Lower West Falls Group (Rhinestreet Formation) on top.

Sonyea Group
Bedrock is Upper Sonyea Group. This marks site of the post-glacial Chenango River channel that was incised owing to ice and sediment blockage in old channel to the west. Northward the valley contains a wide range of outwash deposits, terrace and plain levels, and alluvial fans. The original outwash plain slopes north from 880' to more than 1,000' at Chenango Forks and has been trenched by the Chenango River and Page Brook tributaries.

Turn left
Turn left (west) into Park area. Pass over Page Brook.

Chenango Valley State Park
Chenango Valley State Park entrance. Continue straight and make counterclockwise circuit of Park.

STOP 2
Park in parking area near pavilion. Elevation of sharp ridge is 950' which is 60' above Lily Lake on the north and Chenango Lake on the south, both are kettle hole lakes. The ridge is composed of unconsolidated materials and is probably the finest example of a crevasse filling in this part of the State. The Park contains numerous kettles and plains; however, this is not kame and kettle topography. Instead the stratified materials are largely horizontally bedded (stop 3) indicating transport from the north that engulfed stagnant ice blocks.

STOP 3. Sand and gravel quarries
Sand and gravel quarries in horizontally-bedded glacio-fluviatile materials. A characteristic of quarries in the Binghamton area is coarse material on top with finer material at the bottom which are commonly sands showing cross bedding and deltaic bedding. Continue north and notice many excellent kettles along route, some more than 60' deep.

STOP A-2 Binghamton Brick Co. Quarry
The quarry of the Binghamton Brick Company is developed in the Millport Member of the Rhinestreet Formation. The Moreland Member is exposed at the entrance to the quarry below the level of the main floor. The quarry floor and walls, developed as a series of steps carved from the hill, are composed of beds of the Millport Member.
As in Figure 3, the Millport Member in this locality consists of a series of alternating gray to green siltstone and shale. The shale units range from 10 to 15 feet in thickness, and are generally thin-bedded and fissile, especially where weathering has occurred. Medium-bedded siltstones occur in a somewhat cyclic pattern throughout the section. In the upper part of the sequence, the siltstones are more thickly bedded, and correspondingly the cyclical pattern is not as regular.
Smooth, continuous bedding planes between shale beds and also between shale and siltstone beds predominate; there appears to be little lensing. Small-scale cross-laminations may be observed in the siltstones.
Two prominent flow roll zones may be observed. The first occurs about 100 feet above the floor of the quarry, and the next about 20 feet higher. The flow rolls of the latter unit are numerous, and range greatly in size, shape, and degree of development. Beds of coquina are seen in place and in slump in the upper part of the section.

Tioughnioga River
Keep left, pass over Chenango River bridge to Chenango Forks and intersection with Rt. 12. This area is junction with Tioughnioga River. Excellent exposures of bedrock, till, and lacustrine beds occur 1.2-1.7 mi. upstream in Tioughnioga River. Here it is flowing in post-glacial gorge with bedrock walls. The pre-glacial channel is 2 mi. northeast and parallel to same direction and part of the old stream bed is occupied by Ockerman Brook. (Fig.4)

Post-glacial channel
Along this part of route the Chenango River flows in post-glacial channel, the older channel was east and is now filled. Stratified outwash occurs along west side of route and at high levels above the valley walls are several small 'through-valleys'. These saddles and cols are a type of wind-gap created by high-level meltwater streams when the valley was ice filled and the uplands had become ice-free.

High level saddle
Ascending a high-level saddle, 1070', one of the overflow passes.

STOP 4. Pre-glacial channel
The railroad marks the axis of the pre-glacial Chenango River channel. This area contains many quarries in outwash sand and gravel. A recently drilled well, April 1, 1963, produced 120 gpm from sand and gravel 98' below ground surface.

Terraces and till
Chenango Bridge red light. Turn right and continue west to red light and intersection with Rt. 12, then turn left and continue on Rt. 12 to Prospect Street. Good exposures of outwash and terrace levels in main part of valley floor. On the valley walls are exposures of Binghamton till at Rappaport's and Grand Union.

STOP 5. Borrow pit in Olean till
Old borrow pit on right side of road is in Olean till. Elevation 940'. See text for characteristics of valley fill across the Chenango and Susquehanna valleys. S 300W is well field for ANSCO. Yield of wells range from 150- 1,800 gpm. ANSCO has a recharge program in which water is recycled back into the aquifers. Continue west to the next stop by taking Prospect Street, Harry L. Drive, and just west of Calvary Cemetery.

STOP 6. Borrow pit in Olean till
Borrow pit on right side of road in Olean till. Used as fill in flood wall construction. Return to Rt. 17 on south side of Susquehanna River through Oakdale, Rt. 17H and Riverside Drive, and across Johnson City-Vestal Bridge.

Kettle Hole
Star-Victory marketing area is located in kettle hole. This is one feature in a morainic complex that extends 0.8 mi. west and was the former site of Susquehanna River prior to blockage.

View of terrace
Good view of 860' level terrace, one part of a vast outwash plain that continues west past Tracy Creek.

Binghamton-lithology till in borrow pit on left side of road (stop 9).

Deltaic outwash
Deltaic outwash on south in area of Federal Electronics.

Outcrop of Lower West Falls Group
Bedrock, claystone and shale. Lower West Falls Group (Rhinestreet Formation). Used for bricks and fill.

Choconut Creek
Choconut Creek. Flood walls built by Army Corps of Engineers as part of flood-control project in the Triple Cities area. This area is site of Town of Vestal well field. Wells did not encounter bedrock at 170' and yield 70,000 gallons per day per foot of drawdown. West of this area at Castle Gardens are large quarries in sand and gravel outwash.

Unconsolidated glacial materials on left side of road (Stop 8).

STOP 7. Bedrock walls of Tracy Creek
Bedrock walls of Tracy Creek. (Rhinestreet Formation) This is post-glacial gorge and typical of the many drainage diversions in the Binghamton area. It is common for these derangements to occur near the junction with major streams. This is similar to the Tioughnioga junction diversion. The pre-glacial Tracy Creek channel is east and became choked with morainic debris. The stream, unable to locate its clogged former channel with disappearance of the ice, incised a new channel as a superimposed stream, even though in bedrock.

West side of Tracy Creek
Bus stop only to show the west side of Tracy Creek. Olean till occurs in stream cut but varve clays are at the top of the sequence. This exposure completes the history of this local area for the morainic dam impounded waters flowing north and formed a lake, the outlet of which overflowed and started incisement of the bedrock gorge. The lake may have been in existence more than 200 years. Olean-Binghamton transitional facies also occurs.

Pre-glacial Tracy Creek
Turn sharp left on Ross Hill Road. Outcrops of Olean till occur on the right side of road. This area is site of pre-glacial Tracy Creek.

STOP 8 Borrow pit
Triple Cities Construction Co. equipment area and borrow pit. The glacial deposits are lacustrine sands, silts, and clays at 840' with Binghamton till on top. The till has the appearance of being in part ice-rafted.

STOP 9. Borrow pit
Large borrow pit near African Road. This material was used in construction of flood walls for the containment of the Susquehanna River. This is typical Binghamton till. The oxidized and leached upper 12' are characteristically brown and below is gray unleached till with high limestone content. The pebbles have bi-modal roundness parameters indicating a dual source, one of local derivation, and the other of longer transport that initially were river-worn. The small butte-like remnant is composed of glacial-lacustrine beds at 850'. Recent excavation (April 6, 1963) reveal the locality from African Road to Federal Electronics to be a complexly developed till-lacustrine-deltaic-ice contact area capped by alluvial fan materials.

Outwash terrace
Turn left at African Road and in .2 mi. turn right on Vestal Road. This is outwash terrace with quarries occurring .6 mi. on left side of Vestal Road.

STOP 10. Barney Dickenson Company quarry
This is the second stop called STOP 9 in the guidebook...
STOP 9. The materials originated as valley train outwash in the Susquehanna valley glacial sluiceway. The coarse materials are horizontally-bedded and underlain by sands that are commonly crossbedded. Cemented conglomerates in the southeast part of the quarry show the results of the high limestone content in the lithology. In materials larger than gravel size the limestone is more than 25% and the igneous-metamorphic crystallines are more than 15%. Heavy mineral composition of the sands show more than 40% magnetite, 18% garnet, 10% ilmenite, and also containing kyanite, zircon, tourmaline, hematite, rutile, and hornblende. A mastadon tusk was found in the higher outwash gravels immediately south of the washing-sieving equipment in 1953. It is reported that the skull, jawbone, and teeth of a "horse-like animal" were found in 1956 in the same horizon 700 feet east of the mastadon location. These materials presently reside at Yale University, waiting for final identification.
1962 Annual Report of Barney & Dickenson, Inc.
(sent to U. S. Dept. of Interior, Bureau of Mines)
Type of Material | Quantity (Tons) | Value
2. Gravel | |

C: FACIES AND THE RHINESTREET FORMATION IN SOUTH CENTRAL NEW YORK
Donald L. Woodrow, Department of Geology, University of Rochester
Robert C. Nugent, Department of Geology, Northwestern University
174.8 miles

C: FACIES AND THE RHINESTREET FORMATION IN SOUTH CENTRAL NEW YORK

STOP 1. Doubleday Glen
Exposures of the Dunn Hill and Beers Hill Members of the Rhinestreet Formation. Elevation of exposure: 975'.
After leaving the busses, walk up the hill to the terraced exposure where the dark gray shales of the Dunn Hill Member may be seen. Small flow rolls are exposed here and many additional flow roll zones are visible in the stream bed of the Glen. Excellent view to the southwest, across the Susquehanna River. Red sandstones and shales of the "New Milford Formation" cap the hills visible across the river.

STOP 2. Binghamton Brick Company Quarry
Exposures of Moreland and Millport Members of the Rhinestreet.
Elevation of the quarry floor: 900'.
The very dark gray shales exposed at the base of the quarry are the easterly equivalent of the Moreland Member. No other dark gray shales such as these have been found at higher elevations in the quarry.

STOP 3. East Beecher Hill Road
Exposures of Beers Hill and Roricks Glen Members of the Rhinestreet. Elevation at bottom of exposure: 950'.
The Roricks Glen is represented by scattered, very dark gray shales at the upper end of the exposure. Flow rolls are well developed here. Cyrtospirifer sp. have been reported from strata at bottom and top of exposure.

STOP 4. Smithboro Section.
Smithboro Section. Exposure in Beers Hill Member of Rhinestreet. Elevation: 1000'.
This is an excellent, although small, exposure of Chemung lithofacies and biofacies. Massive sandstones and underlying mudstones are highly contorted in large flow rolls. Numerous brachiopods, pelecypods, and rugose corals may be collected.

Beers Hill Member
Exposure in Beers Hill Member, approximately 75 feet above the Dunn Hill member: lithologies Portage-like with rare, diminutive forms ofCyrtospirifersp. reported.

STOP 5. Chemung Narrows. (0.4 mile stretch)
Exposure in the Gardeau Formation. Elevation: 800'.
This exposure is one of the most famous Upper Devonian sections in North America. Here, the typical features of the Chemung magnafacies are developed and well exposed. Notice the well formed flow rolls and prolific fauna. The proximity of this exposure to the highway makes it unsuitable as a place for discussion; therefore, we will move a short distance west and cross the Chemung River to a similar exposure, stratigraphically higher.

STOP 6. Wellsburg Section.
Exposure in the Gardeau Formation. Elevation: 840'.
This is a fresh (1962) exposure of lithologies similar to those seen at stop 5. Flow rolls are rare, but fossils may be collected readily. This road-cut and the section exposed along the railroad below the road served as the type section of Williams, Tarr, and Kindles "Wellsburg Sandstone Member of the Chemung Formation" (1909).

Gardeau Formation
Sandstones of the Gardeau Formation exposed on north side of road.

Millport Member of Rhinestreet Fm
Leave 17 for Elmira via East Church exit (extensive cuts in the Millport Member of the Rhinestreet Formation on the north side of the exit ramp.)

STOP 7. East Church Street Quarries
Leave busses at first dirt road to right after crossing bridge. Walk to quarries.
Exposure of the .Millport and Dunn Hill Members of the Rhinestreet. Elevation 910".
A comparison of the lithologies displayed here with the lithologies seen in the Millport of the Binghamton region illustrates the facies changes that have occurred. At the top of this quarry may be seen the heavier-bedded siltstones and fine-grained sandstones of the upper Millport. The quarry floor and lower faces are cut into the black and very dark gray shales of the Dunn Hill Member.

STOP 8. Type Section of Dunn Hill Member.
Leave busses at first dirt road to the right (north); walk to stream exposure.
Elevation: 1010'.
In this stream, the Dunn Hill Member is 22 feet thick and is composed of gray, silty shales and mudstones with nearly eight feet of black and very dark gray shales of which the majority is concentrated in the basal ten feet of the member. A tributary of this stream draining the hill to the south is the type section of the overlying Beers Hill Member of the Rhinestreet.

STOP 9. Reference Section for Moreland Member
Black shales of the basal Moreland are exposed. Elevation: 1380'.
Owing to time limitations, the type section of the Moreland Member (in Hamilton Creek, one mile north of this stop, elevation: 1370') will not be visited, however, the black shales may be observed here. In addition, the limey mudstones and shales of the underlying Rye Point Member of the Sonyea Formation are well exposed in this stream.

Ithaca Formation
On the right (west) side of 14, exposures of the evenly bedded siltstones and shales of the Ithaca Formation are continuous from Watkins Glen to Montour Falls.

Ithaca Formation
Road cuts on north side of road; excellent exposure of siltstones in upper part of the Ithaca Formation.

Montour Member (Middlesex Formation)
Exposure of Montour Member (Middlesex Formation) under bridge in center of town.

Millport Member
Exposures of Millport Member on right (south) side of road.

Langsford Creek occupies valley on the left (north).

Beers Hill Member
Excellent exposures of the Beers Hill Member of the Rhinestreet in the hillside directly across the intersection from the bridge. Other exposures may be seen along 38 to the left (north).

D: GENERAL GEOLOGY OF THE WESTERN CATSKILLS
Donald R. Coates
132.5 miles

D: GENERAL GEOLOGY OF THE WESTERN CATSKILLS

STOP 1 Glacio-fluviatile and glacio-lacustrine beds
Outcrop of glacio-fluviatile and glacio-lacustrine beds intermixed with till and a deltaic complex. Lithology of the larger rocks includes red sandstone, local siltstone, and coquinite, and some igneous-metamorphic crystallines. Limestone is rare. The Susquehanna River is 810' and adjacent hills are 1500'-1600'.

Glacial Channels
Stay on Rt. 17 as Rt. 11 turns south. The wide area of unconsolidated materials was produced by junction of the west-flowing Park Creek and south-flowing Stanley Hollow. The latter stream was a major overflow channel of glacial waters when the ice front was north of the area.

Climbing out of the Susquehanna valley
Stay on Rt. 17 at Penn-Can turnoff. Climbing out of the Susquehanna valley. Will see Susquehanna again at Windsor.

STOP 2. West Falls Group
Lithology is largely shale and siltstone with some fine-grained sandstone. A few thin coquinite beds are present containing brachiopods and crinoid columnals. The original limestone has been removed. Several excellent horizons of flow rolls occur. The lack of parallelism of flow rolls and bedding planes is seen in the easternmost part of the outcrop. Radiographs done at Harpur (Greene and Coates, 1963) of sections cut at different orientation of the flow rolls indicate some interior structures of small-scale folding and gravity faulting. An angular unconformity occurs at this stop. Rocks also contain many other structures, both primary and secondary in origin. Next to the bedding characteristics in rock importance is the universality of the joint patterns. Two sets are well-developed throughout the Catskill region.

West Falls Group
West Falls Group on south side of road. Similar to stop 2. Throughout this area the hills are capped by sandstones of the continental facies of the Catskill delta-alluvial plain complex, but only marine facies rocks are visible along the road at the lower elevations.

Walk on the west side of house down to flood plain of Occanum creek about 500 feet. On south side of creek is 50' high outcrop of Olean till (Catskill phase). The bedrock that occurs upstream indicates that in places Occanum Creek occupies a post-glacial channel.

Terrace development
Excellent terrace development at the community of Occanum. The origin of this type feature will be discussed later.

Choker Moraine
Thick till "choker moraine". This feature is also common along the route that will be travelled and it will be discussed later.

Susquehanna River
The Susquehanna River, elevation 920', flows south. The hills are 1700'- 1900'. Occanum Creek forms an alluvial fan and the village of Windsor is built on the junction of the alluvial fan and the 980' level of outwash developed by the Susquehanna River in glacial times during ice recession. This terrace extends to Sage Brook and Rt. 79 utilizes it. Well-developed flood plain occurs in the present Susquehanna channel area.

Sage Brook.
Top of alluvial fan is 1000'. Olean till (Catskill phase) is exposed on north side of stream. This is the southern edge of the morainic barrier that extends northward around the river meander.

Channel, terraces, etc.
Turn right (east) at Ouaquaga over Susquehanna River and keep left at road Y .2 mi. Good view of present channel, plains and terraces on this west-flowing stretch of river.

STOP 4. Gravel Quarry
This is a .25 sq. mi. area of stratified glacial deposits. Materials have a wide range of size, composition, and structural forms. The history of this area originated with blockage of the river by ice and morainic deposits in the channel to the west. The glacial meltwaters were diverted to a low pass east of the former valley, causing incisement of the former divide. Further recession of the ice front occurred with the abandonment of stagnant blocks that melted more slowly owing to favorable positions of insulation. These conditions account for the complex bedding, size, and sorting of material relations. Much evidence of ice-contact deposits, lacustrine conditions, deltaic sedimentation,and valley train outwash is visible. Disconformities occur indicating an erosional interval separating deposition of older and coarser materials from younger sands. In some of the outwash sands there are veinlike structures composed of "bridged" grains. Norma] faulting is also present. Travel in and out of quarry is .6 mi.

Overflow Channel
From the quarry take the road south to East Windsor, pass under the tracks and turn right (south) at the T. This valley is the former overflow channel of the Susquehanna that was in turn abandoned when the drift dam was breached in the older channel to the west. Elevation of the pass is 1000'

Damascus - Marine / Non-Marine interfingerings
Damascus. To this point the route elevation has been 900'_1050' and at this level all bedrock is marine. Rock exposures in the new Rt. 17 roadcuts at Damascus indicate this is the strand line at road level. There are many interfingerings of marine and non-marine beds at this locality. Eastward the rocks are mostly non-marine. Damascus is on an incised alluvial fan of Tuscarora Creek. The road now climbs what is locally called "Tuscarora Mountain", and hill elevations are over 1900'.

Non-marine strata
South of the road is the first visible exposure of the non-marine strata of the Catskill delta-alluvial plain complex. Formations are still in the West Falls Group and are continuous for more than one mile.

Deer Lake.
Deer Lake. This lake along with Sky Lake one mile north and Fly Lake one mile south occur in the drainage of Fly Creek. The amphitheater-like basins all contain constrictions on the south suggesting their glacial origin of impoundment of south-flowing Fly Creek behind morainic loop dams. This pattern is repeated throughout the Catskill area.

Turn right (south) to Gulf Summit. This area contains a great variety of glacial deposits, many are stratified. This is a topographic hollow with slopes rising on all sides, and thus was the locus for a large stagnant ice mass. The meltwater drainage was southwest and a deep notch was incised southwest of the village. This is now the divide, elevation 1375', between Cascade Creek flowing west to the Susquehanna River and a tributary of Fly Creek flowing east to the West Branch Delaware River. (see Fig.7 and 8) Cascade Creek with greater gradient is capturing drainage that formerly went eastward. 2.2 mi. round trip to Gulf Summit and return to Rt. 17.

Sand and Gravel Quarry
North of road is sand and gravel quarry developed in materials that indicate deltaic and glacio-fluviatile origin. These deposits are typical of the Otisville gravelly loam that occurs as a terrace-band through this area at elevations that reach 1410'. Thus, at a minimum there has been more than 36' of post-glacial incisement through the pass at Gulf Summit.

Former location of an esker
Junction of Rts. 17 and 41. At this location on north side of road was a well-developed esker, recently demolished during construction of the new road. From this point to Deposit in the Oquaga Creek valley are many glacial deposits, including high-level hanging deltas. See text for data on Oquaga Creek.

Deposit - Lunch Stop
LUNCH STOP at the Jordan House. This town is often given as the western boundary of the Catskill Mountains. Eastward the rocks are all continental, (Fig.4) and the stratigraphy for the general area is the Sonyea Group, with the Stony Clove and Lower Katsberg formation in the valley and lower slopes and the Upper Katsberg formation of the West Falls Group on the higher slopes and capping the mountains.

Upper Katsberg beds
Turn on Rt. 10 left (east) at stop light. stay on Rt. 10 to Cannonsville, 9.2 mi. The route parallels the west-flowing West Branch Delaware River. Upper Katsberg beds will be seen on left, with cross bedding, typical of many non-marine sandstones. Large outwash area is present on south side of river.

Temporary end of Route 10
Old Rt. 10 has been abandoned east of intersection of Rt. 8 and Cold Spring Creek. This is new bridge over the river and all the new construction was necessitated by development of Cannonsville dam and area as a reservoir for New York City. Work is done through the office of the Board of Water Supply.

Massive continental sandstones.
Massive continental sandstones. This is near contact of Upper Katsberg and Slide Mountain formations. Good exposures for .8 mi.
From one page handout (1963): Spectacular rock cut in diversion channel showing more than 100' of non-marine Catskill-type beds. Channel filling, faults, variations in color and lithology.
2010: Reservoir filled in 1964-5, so much may now be inundated.
DEC Unique Geologic Landforms 180: Deposit State Hwy 10

STOP 6. Cannonsville Dam
Picture stop for Cannonsville dam area. The Board of Water Supply, City of New York was created in 1905. Since that time water use in New York City has risen from 400,000,000 gallons per day to 1,200,000,000 gpd in 1955. Estimated usage for the year 2000 is more than 1,900,000,000 gpd. The Catskill system of reservoirs was started in 1907 for eastern drainages. When these supplies appeared inadequate for continued growth of the City, enabling interstate legislation was undertaken to use Catskill drainages of the west-draining Delaware River. In 1931 by court action 440,000,000 gpd could be used by the City and this was increased to total usage of 800,000,000 gpd in 1954. Total cost for the present Catskill reservoir system is well over $1 billion. The Cannonsville Reservoir will impound 97.4 billion gallons in the 450 square mile drainage area of the West Branch Delaware River. The dam is an earth embankment about 1,500' long and 175' high. The water supply will move by gravity through the West Branch Tunnel to the collecting Rondout Reservoir. The tunnel will be 44 miles long and 11.3 feet in diameter. Estimated cost of the dam and reservoir construction is about $60 million and the tunnel at $81 million. (Source: 50th Anniversary Report of the Board of Water Supply).

STOP 7. Catskill-type red beds.
Catskill-type red beds. View of the village of Cannonsville that will be inundated when construction of area has been completed. (see Cover page for picture taken prior to construction). 2010: Location is about as close as the dry land gets to where Cannonsville was.

Ascent of Trout Creek
Pass over West Branch Delaware River and at Cannonsville turn right .2 mi. then left (north) up Trout Creek. (see text for Trout Creek data) Cannonsville was built on materials that developed a small alluvial fan and terrace. Soil classification is Tunkhannock gravelly loam. It is 114' to bedrock. A variety of phenomena can be seen during ascent of Trout Creek. The valley slopes are in places bedrock (lower Katsberg Formation), and in others show unconsolidated materials some till, some stratified outwash and kame terrace deposits, and probably some of the large blocky rocks are in the range of congeliturbites. In places the road is on a terrace and there are constructional hills, mostly kames, developed in a valley-choker type of morainic complex. North of the kame and terrace area are flat plains of lake deposits impounded by the stagnant ice.

Lacustrine Sands
Lacustrine sands were uncovered during construction of the new bridge and another well-developed lake plain occurs upstream from this locality.

Alluvial fan
Rock Royal. Sherruck Brook has developed an alluvial fan and associated with it is glacial outwash. On east side of Trout Creek are more exposures of stratified outwash. Lake plain occurs north of this area.

Trout Creek
Village of Trout Creek and intersection of Rt. 206. Continue north. Valley fill is 60' thick.

Glacial topography
Glacial constructional topography of knobby-morainic hills, incised by a post-glacial, V-shaped gorge. This pattern will be seen many times on the trip.

Bedrock and morainic loop.

STOP 8. Stone net
Stone net in lower Katsberg Formation. This was first noticed by E.H. Muller. Open meadows such as this, throughout the Catskills, often show similar features. The slabs develop polygonal shapes, and constantly change in attitude from the center of a net. There is also some tendency for size-sorting of slabs. The original spacing of joints seems to influence the location and development of the nets. Frost heaving and ice wedging aid in deterioration and movement of the slabs.

Drainage divide.
Drainage divide for Susquehanna and Delaware systems.

Morainic loop.
Morainic loop on left side of road with post-glacial gorge.

Man-made lake.

Gulf Oil Company test well
This is site on right side of road of Gulf Oil Company test well drilled by Delta 29. On March 16, 1963, 3800' of rock had been drilled in about a month. Apparently the hope is that Oriskany sandstone when encountered will contain oil or gas of commercial value. From this position the road descends to Ouleout Creek drainage area.

STOP 9. East Sidney Dam
East Sidney Dam and Ouleout Creek drainage area. See manuscript for data on Ouleout Creek and Figure 9. Turn right .3 mi. to dam. Oneonta formation red beds occur at base of dam. East Sidney Dam built by Department of Army, Corps of Engineers. Completed 1950.
Dam characteristics: |
Quantity of concrete: | 156,000 cu. yd.
Height above Ouleout Ck.: | 130'
Length of Spillway crest: | 240'
Total length of concrete dam: | 750'
Embankment: |
Rock Fill: | 113,000 cu. yd.
Earth Fill: | 194,000 cu. yd.
Excavation: |
Take Rt. 7B from the dam going east WEST until intersection with Rt. 7. This part of road traverses excellent kame and kettle topography. There are two well-developed lower terraces before Ouleout Creek unites with the Susquehanna River. Sands and gravels are Tunkhannock gravelly loam, the upper terrace is Tioga silt loam and lower terrace is Chenango silt loam.

Oneonta formation
Rt. 7 turn left (south) to Unadilla. Oneonta formation crops out along railway cut. Susquehanna River flows south, elevation 1000'. Hills rise to 1900'.

STOP 10. Quarry
STOP 10. Quarry southwest side of Unadilla. This area is kame and kettle topography within a morainic complex that impounded meltwaters during glacial recession. Extensive lake plains and terraces levels and remnants of levels occur from this position upstream several miles. This pattern is repeated several times downstream in the Susquehanna valley. See text for description of lithology.

STOP 11. Masonville Quarry
Owned and operated by The American Blue Stone Company, New York, N.Y.: has been in operation since 1945. (See Fig.6) Current level working area is about 250' x 100' and production is confined to mill blocks. The processing plant is in South Unadilla. The quarry is flooded during the winter months to a height five feet above the lower bench to protect the stone from ice and frost damage. Mr. James J. Newberry has kindly qiven information about the quarry and has given permission to visit it. The mill processes 16,000 cu. ft. of stone from this quarry.
DEC links 1 2 3

River confluence
This is near the confluence of the Susquehanna and Unadilla Rivers. Streamflow of these rivers in this area are: Susquehanna River at Unadilla, N.Y., 1,626 cfs for 984 sq. mi. drainage area, and Unadilla River at Rockdale, N.Y., 842 cfs for 518 sq. mi. drainage area. Although the Susquehanna has two times the flow today owing to the larger drainage area, it is probable that the Unadilla carried more water during the ice ages. The headwaters of the Unadilla are at lower elevations than most Susquehanna tributaries and the major tributaries of the Unadilla occur in through-valleys. Overflow of the glacial lakes in the Mohawk Valley Region therefore found ready-made outlets in such rivers as the Unadilla and Chenango, and turned these valleys into giant sluiceways for the impounded glacial waters. There is a high-level drainage channel of the Unadilla in the saddle that occurs just east of Mt. Moses, the hill that rises north of the intersection of Rts. 7 and 8. Throughout the Sidney area are outwash sand and gravel quarries. Terrace development is common and a good view of the 1010' level occurs on the south side of river.

Outwash materials
Quarry outwash materials, coarse and rubbly at the bottom and finer sands and gravels at the top. The road is built on the 1010' terrace level. 2010: GE says 990'.

Bainbridge
Bainbridge is built on the 1010' terrace. Susquehanna River is 975! 2010: GE says 990' and 962'.

Olean till
Olean till on right side of road. (See text for description).

Ice contact features.
Sand and gravel area. Ice contact features are present. The Susquehanna is incised through the outwash plain.

Kettle hole lake
Afton Lake, a kettle hole lake. This is kame and kettle topography, created in part by a morainic complex. The locale is characteristic of many others in the Susquehanna valley, in which the constructional topography occurs near the junction of the Susquehanna and a tributary. The south-flowing Kelsey Brook is an underfit stream and the morainic areas are upstream in the Susquehanna valley.

Kame and kettle
More kame and kettle topography near the mouth of the north-flowing Cornell Creek on the south side of the Susquehanna valley.

STOP 12. The Plains
The Susquehanna River 950' elevation has incised more than 100' through a broad and exceptionally well-preserved 1060' terrace level, called "The Plains". Remnants of this level can be found several miles along the Susquehanna.

Leaving Susquehanna River
We are now leaving the Susquehanna River which turns south. The road ascends Belden Brook up to Belden Hill.

STOP 13. Parking area
Elevation 1650'. Near the Chenango-Susquehanna drainage divide. View to the south provides appearance of accordant summit levels. The summits actually range between 1600' and 1850'. Westward the road follows a tributary of Osborne Creek, an underfit stream. There are a series of at least four different morainic loops in this tributary system of the Chenango. These choker moraines occur at intervals from the parking area of 1.6 mi., 1.6 mi., .5 mi., and .9 mi. Notice the flat topography that is always upstream of these constructional areas.
2010: This is the last stop from the 1963 Field Trip. They returned to Harpur by older roads, we go back to SUNY Binghamton by expressways...

New York State
Geological Association
Guidebook
John James Prucha, Editor
Department of Geology, Syracuse University, Syracuse, N.Y.

A: GEOLOGY OF THE SOUTH-CENTRAL ADIRONDACK HIGHLANDS
Cedar River - Blue Mountain section (CR)
by Dirk de Waard
Snowy Mountain Section (SM)
by William D. Romey

STOP CR 1. View to SW from Cedar Bend Lodge
View towards the southwest from hill opposite Cedar Bend Lodge (ask permission). In the Cedar River valley marble and other supracrustal rocks are exposed which are folded in a synclinal keel wedged in between the Snowy Mountain dome towards the south (left) and the Wakely Mountain nappe towards the west (right). Dip of foliation and bedding in the structure is to the northwest (right), and the fold axis plunges west. Dip slopes of the Snowy Mountain dome are visible towards the south. Gneisses of the Wakely Mountain nappe are exposed in Wakely Mountain, Round Top, and Blue Ridge to the west. Sugarloaf Mountain in the center is the gneissic core of the syncline.

STOP CR 2. Charnockitic gneisses
Ledges in bushes on right are charnockitic gneisses which form the uppermost overturned portion of the core of Wakely Mountain nappe. Stratigraphically overlying amphibolite and marble are exposed in several places along the road.

STOP CR 3. Supracrustal strata
Stop 3. Short walk up hill to the right to the first ledges of Sugarloaf Mountain. Traverse across supracrustal strata of diverse composition (marble, amphibolite, layered gneisses, diopsidic quartzite and gneiss, diopsidite) towards the core of the syncline which consists of gneiss.

STOP CR 4. Trail to Cedar River falls
Small trail to the left down to the Cedar River. Gorge and falls in marble. Walls demonstrate intense plastic deformation and flow folding in the marble, distortion and rotation of amphibolite pieces. Exposures of amphibolite, quartzite, and sillimanitic garnet-biotite gneiss.

STOP CR 5. Large garnets
On the left, about 30 meters in the bushes, is a small outcrop of amphibolitized metadolerite (sill in charnockitic gneiss of Stop 6). The amphibolite consists of andesine, hornblende, and orthopyroxene. The exposure shows some large garnet porphyroblasts (15 cm diameter) similar to those of the famous Gore Mountain occurrence. PLEASE DON'T SAMPLE THE GARNET HERE. Others may like to see this outcrop after you.

STOP CR 6. Core of Wakely Mountain nappe
Road cut on the left shows typical grey-green, hornblende-bearing, perthitic charnockite of the basement core of the Wakely Mountain nappe.

STOP CR 7. Large road cut
Large road cut on the north shore of Lake Durant. The section of diverse, layered metamorphic rocks includes pink and greenish leucocratic gneisses with thin metabasic layers, marble, and calc-silicate rocks. The section forms part of the supracrustal sequence which overlies the leptites of the Wakely nappe exposed in the hills visible towards the south across the lake, and which underlies the Blue Mountain charnockite sequence towards the north. Lineations on foliation planes indicate a 30° NE plunging fold axis. The intrusive nature of marble into boudinaged layered gneiss is shown on the west end of the north side of the road cut.

STOP CR 8. Supracrustal charnockite
Road cut on the right just downhill from diner, in charnockite of the supracrustal sequence. The grey-green charnockite, interlayered with metabasic rocks and tremolite schist (in the brook), is part of a series of charnockitic rocks which presumably forms an isoclinally folded, complex syncline (Blue Mountain). The charnockite layers, which overlie the marble exposed in the lake and the rocks of stop 7 north of Lake Durant, form part of the supracrustal envelope of the Wakely-Mountain nappe. The Blue Mountain charnockite sequence is considered to be equivalent to the Little Moose Mountain sequence of charnockites. They are stratigraphically the youngest supracrustal rocks known in this area. The composition of the charnockite at this stop is predominantly:

STOP CR 9. Large migmatite exposure
Large exposure in the brook on the right shows pattern of typical migmatite (crocydite) in quartzofeldspathic metamorphic rocks of the Adirondack highlands. The metatect is anatectically generated granite in hornblende-biotite-quartz microcline microperthite oligoclase gneiss. The gneiss grades into charnockite and belongs to the Blue Mountain charnockite sequence.

STOP SM 1. Augen gneiss of Snowy Mtn dome
Stop 1. Roadcuts O.1 miles west southwest of trail leading to the top of Snowy Mountain. K feldspar-plagioclase-quartz-andesine-pyroxene-hornblende augen gneiss (charnockitic "Keene"-type gneiss) of the type which is widespread in Snowy Mountain dome. Foliation about horizontal.

STOP SM 2. Leuco metanorite
Stop 2. From the highway walk west a few yards along a narrow dirt road to flat outcrops. Andesine-pyroxene-hornblende gneiss with relict ophitic to hypidiomorphic granular texture preserved. Note relict cores of dark gray plagioclase (An42) surrounded by recrystallized plagioclase (approximately An34). Square masses of plagioclase are outlined by partially recrystallized mafic minerals. This rock is similar to some of Buddington's gabbroic anorthosites, but we have preferred to call it a (leuco) metanorite. Foliation dips west southwest at a low angle.

STOP SM 3. Anorthosite
Stop 3. Large roadcut on the hill 0.4 miles southwest of the intersection of highway 30 with the lake shore road through Sabael. Anorthosite at the lower end of the outcrop is overlain by metanorite (unfoliated andesine-pyroxene-hornblende gneiss) which is in turn overlain by streaky andesine-pyroxene-hornblende augen gneiss. Both "Marcy-" and "Whiteface-" type anorthosites are present. The grain size of metanorites ranges from coarse to fine, and the original texture of the rock is preserved to various degrees in different parts of the exposure. Several small amphibolite (metadolerite) lenses may be observed in the streaky gneiss. Foliation is nearly horizontal. Walk up the steep hillside above the road to see massive ledges of anorthosite, metanorite, and a rock which is texturally and compositionally intermediate between these two types.

STOP SM 4. Well foliated gneiss
From the intersection of highway 30 with the lake shore road through Sabael walk east about 100 yards on a private road (get permission) leading to a house on a small peninsula. Outcrops are on the lake shore east of the house. Well-foliated K gneiss (charnockite). Domal structure of the complex on the east side of Indian Lake can be observed from the point east of the intersection.

STOP SM 5. Charnockitic augen gneiss
Roadcuts on the main road 0.1 miles northeast of Squaw Brook. Charnockitic augen gneiss similar to the rock seen at stop number 1 (K gneiss).

Banded gneisses in roadcut
No stop. From the bus observe banded gneisses in roadcut. K feldspar-quartz-plagioclase-amphibole gneiss is interlayered with plagioclase-hornblende-biotite amphibolite.

STOP SM 6. Last of the anticlinal core rocks
Stop 6. Roadcuts consisting of well-foliated, homogeneous, leucocratic charnockite (K feldspar-quartz-plagioclase-pyroxene-hornblende-garnet gneiss). A few amphibolite layers are present. This is the granitic end-member of the "syenite" series of Buddington. This is the last stop in what we have called "anticlinal core rocks".

STOP SM 7. Supracrustal rocks
Roadcuts consisting of banded microcline-quartz-plagioclase-hornblende-pyroxene gneisses. These are the first clearly supracrustal mantle rocks overlying the anticlinal core rocks. Note intense folding of the gneisses.

Extra STOP SM 1. Gneiss with large diopside clots
Roadcuts of feldspathic gneisses containing large diopside clots. About 0.2 miles west of the road are spectacular exposures of the same gneiss in a newly reopened quarry (get permission to visit).

Extra STOP SM 2. Amphibolite and marble
East of Indian Lake village on highway 28 there are flat outcrops of amphibolite and very coarse-grained white marble at the outlet to Adirondack Lake. At times of high water these cannot be easily seen.

B: GEOMORPHOLOGY OF ONEIDA BASIN AND SOUTH SLOPE OF THE TUG HILL PLATEAU
by Ernest H. Muller, James S. Street and Jesse L. Craft

B: GEOMORPHOLOGY OF ONEIDA BASIN AND SOUTH SLOPE OF THE TUG HILL PLATEAU

Rise onto drumlinoid with veneer of red till.

Iroquois lake plain at 410 ft. msl.
Continuing on N.Y. Rte. 290, cross overpass and descend to level of Iroquois lake plain at 410 ft. msl.

Fremont Hill drumlinoid
Continuing on N.Y. Rte. 290, rise onto Fremont Hill, a drumlinoid that was an island in Iroquois Lake. Strand features are mapped at the 435 and 420 ft. levels.

Cemetery at 430 ft
Cemetery on right (S) as road returns to lake plain is at the 430 ft. level. Cross alluvial flats of Limestone Creek.

Abandoned feeder of Erie Barge Canal
Cross abandoned feeder of Erie Barge Canal and rise from Iroquois lake plain onto intensely scoured scarp developed on Syracuse fm. Excellent exposures of Syracuse fm in railroad cut, off route .4 miles SW.

Route parallels Erie Canal
At "t-intersection", turn left (E) to continue on N.Y. Rte. 290. Route parallels Erie Canal, with Iroquois lake plain on left and scoured, thinly veneered slopes on right.

STOP 1. Green Lakes State Park
Examination of notched Green Lake channel and Round Lake plunge pool. Discussion of meltwater channels, plunge pool development, interrupted plunge pool migration and limnology of Green Lake. See text, p.31.

Mouth of Green Lake channel
Turn right (E) onto N.Y. Rte 290. Embayed mouth of Green Lake channel debouched into Lake Iroquois at right.

Descend across weak 435 ft. strand
Descend across weak 435 ft. strand at curve in road. Cross abandoned Erie Canal and continue north through Kirkville on littoral sand and gravel.

Iroquois lake plain
Cross N.Y. Thruway overpass affording broad view of nearly level Iroquois lake plain. Pine Plains lie ahead right.

Dune and blow-out complex
East of first cross-road note yellow-brown sandy soil and irregular low relief of dune and blow-out complex related to strandline of late phase of Lake Iroquois which lies parallel and just north of the route for the next 3 miles. Dune configuration suggests dominant effective winds from the west-northwest.

Sand dune complex
Follow road in 90° curve to the right (S), then turn left (E) immediately at "T-intersection" to continue east on Chestnut Ridge Rd. through sand dune complex that borders Pine Plains on the south and Canastota mucklands on the north.

Cicero stage of Lake Iroquois
Turn left (N) onto Chittenango-Lakeport Plank Rd., In .2 mi. descend about 20 ft. across strand that marks Cicero stage of Lake Iroquois (Coon, 1960). Surface of Canastota muckland is approximately at 385 ft. msl.

STOP 2. Sky-High Farms
STOP TWO. SKY-HIGH FARMS (Smith-Coulter Co., Inc.) Peat, marl and bottom sediments of Cicero stage of Lake Iroquois, illustrating succession in filling of post-glacial embayment. Pulmonate gastropods in marl.

Eastward extension of the Lockport cuesta
Turn right (E) onto Lake Rd. in Lakeport. For next 7 miles, Oneida Lake is on left at 369 ft. msl, while a broad swell, elongate east-west, rises to the south of the route. Although it is virtually without bedrock exposure, this rise is considered to be an eastward extension of the Lockport cuesta.

Beach ridge
Turn left (N) onto N.Y. Rte. 13 across Oneida Lake plain. Cross Oneida Creek and continue on minor beach ridge, one of several at 375 ft. msl. that indicate steadily prograding east shore of Oneida Lake.

STOP 3. Verona Beach State Park
Rest stop. Summary of Iroquois lake history and Oneida basin geomorphology as encountered en route and at previous stops.

Oneida lake plain
Turn left (N) onto N.Y. Rte 13. Proceed across Oneida lake plain. Relief is less than 15 ft. for several miles to the east and the deepest part of the lake is only 55 ft. deep. This plain and basin occupy the structurally controlled lowland on the Clinton Group.

Erie Canal
Cross Erie Canal at Fish creek between Verona Beach and Sylvan Beach. In April, 1963, wind-driven shore ice rammed across the beach and against roller-coaster in amusement park at canal outlet into Oneida Lake.

Rise from Oneida Lake plain
Begin rise from Oneida lake plain across Iroquois nearshore and strand deposits. Medina-Clinton contact concealed and not established as having any relation to the shore scarp. At the "Sand Bar" on right, a low cut exposes 3 ft. of red-brown sand and silt over 8 ft. (base concealed) of red to red-brown rhythmically-laminated, but not varved, clay and silt. A well 1.5 miles southeast was drilled through 250 ft. of unconsolidated sediment reported to be dominantly lacustrine. The hole bottomed at 125 ft. msl without reaching bedrock.

Minor drift bench.
Turn right (E) on N.Y. Rtes 13 and 49 along a minor drift bench. Borrow pits dominantly expose ablation drift. Iroquois lake plain extends many miles east-west on right along trend of non-resistant Clinton Group.

Moraine divide
Turn left (N) in Vienna, following N.Y. Rte 13. Cross moraine divide between Oneida and Fish Creek basins.

West Branch Fish Creek
Cross West Branch Fish Creek. Pass Harden furniture plant and proceed north across remnant of Williamstown outwash plain.

STOP 4. G. W. Bryant Sand Pit
Examination of structures in stagnant ice deposits; discussion of aspects of sand and gravel industry.

Shallow meltwater channel
Proceed north following shallow meltwater channel incised into stratified drift of kame and kettle complex.

LUNCH STOP.
LUNCH STOP. Camden Methodist Church, served in Walker Memorial by Women's Guild.

STOP 5. Camden Wire Company Esker
STOP FIVE. CAMDEN WIRE COMPANY ESKER Examination of composition and structure as exposed in transverse and longitudinal sections of a small esker. Significance of "pseudo-anticlinal" structure in transverse section.

Stagnation features
Turn right (E) onto Pond Hill Rd. Continue across stagnation features marking progressive decay and wastage of the late Cary Oneida ice lobe.

Boulder gravel
At top of rise note boulder gravel exposed in road cut. Poorly sorted glacial drift is thick and bedrock is unimportant as a control of local relief in this area.

Climb sharply to higher bench.

STOP 6. Mack Pond Kettle Cluster
Examination of topographic and hydrographic relationships in a compact cluster of kettles and crevasse ridges at edge of the Pond Hill terrace.

Shallow marginal drainage line
Proceed east on Pond Hill Rd. Cross shallow marginal meltwater drainage line before rising sharply.

Head of meltwater channel
In one mile note swampy area on left which is at head of one of a series of eastward draining meltwater channels.

Cemented cobble gravel
Just before road enters shallow cut, cemented cobble gravel can be seen in overgrown cut 200 yds south of road. Leaving roadcut, descend on Rte. 69 over 30 ft. scarp which appears to be wave-cut.

Meltwater channels
Turn left in Lee, onto Lee Valley Rd. Cross Sash Factory Creek in swampy swale, the downslope continuation of meltwater channel seen on left 2.5 miles earlier. The right angle bend between channel segments suggests a subglacial meltwater escape-way. On right (S), shallow meltwater channel-way parallels road, curving eastward at about 520 ft. msl.

Cemented cobble gravels exposed on left (W)

Meltwater channels
Entering Lee Center, cross swampy meltwater channel with small pond on left and cannery on right. Channel alignment continues east from Lee Center as an obvious meltwater channel segment, but at slightly higher elevation than floor of the swampy channel segment that enters Lee Center from the west. Apparently segmentation of marginal drainage-way resulted from development of a subglacial escape-way downslope, now occupied by Canada Creek and Mill Road south of Lee Center.

Pass Sulphur Springs Rd
Exposures of Whetstone Gulf shale on left indicate probable of source of sulfur as being from decomposition of pyrite.

Outwash bench
Rise sharply and proceed east across outwash bench. Pass between Rome Reservoirs and angle across bench to Stokes.

Edge of Tug Hill Plateau
Begin rise across Quaker Hill, the southeastern tip of the Tug Hill Plateau developed on rocks of the Lorraine Group.

Ice walled meltwater channel
Minor bench and northward rise are remnants of former ice walled meltwater channel that is better developed about a mile west, and trends eastward toward Mohawk Valley.

West Branch Mohawk River
Cross West Branch Mohawk River at village of West Branch.

Diffuse moraine runs N-S
Continuing north on N.Y. Rte. 26, rise onto diffuse moraine that trends north-south, with best development of constructional topography west of the route between Ava and West Leyden. This is the first moraine of the Black River lobe encountered on this trip. The larger Oneida glacial lobe dominated and outlasted the Black River ice in this interlobate area in the lee of the Tug Hill nunatak.

East Branch of Mohawk River
In West Leyden, jog right with N.Y. Rte 26 to cross East Branch Mohawk River.

Increase in field boulders
At Redmond Corner, intersection with Webster Hill Road, continue eastward and begin to descend toward Boonville. Note increase in abundance of field boulders. In about a mile pass through area of minor stagnant ice features.

Black River Canal
Rte. 12 parallels the Black River Canal, built in 1855 to link navigable reaches of the Black River north of Lyons Falls with the Erie Canal at Rome. With a total of 109 locks in 35 miles the canal crossed a divide 700 feet above the Erie Canal. The substantial remains of a dozen or so locks are seen between Boonville and Sugar River which was crossed by aqueduct.

STOP 7. Sugar River at Boonville quarry
E. G. DeLia and Sons, Inc. Examination of stratigraphic section in quarry and of solution features along Sugar River.

Descend into channel
Continuing on N.Y. Rte. 46, descend 30-ft into broad flat-bottomed, rock-floored channel across ledge that controlled outflow from proglacial Port Leyden Lake through the Lansing Kill or Boonville Gorge. Continue south in channel, crossing diagonally to east side, thence back to west side to parallel the old Black River Canal.

Booneville Gorge
Shale bluff in roadcut on right indicates erosivity of rock into which the Boonville Gorge is cut. From Boonville to this point the gorge has become progressively more constricted. At left where Lansing Kill enters from the east side of the valley, post-glacial notching accounts for abrupt deepening of the gorge.

STOP 8. Boonville Gorge State Park. Pixley Falls
Rest stop. Consideration of significance of Lansing Kill Gorge.

Five adjacent locks
Five combines -- a flight of 5 adjacent locks on Black River Canal.

Mohawk River
Mohawk River enters Boonville Gorge from west with development of multiple terraces now incised by both Lansing Kill and Mohawk River.

Apex of meltwater delta
Village of Westernville, on right, near apex of delta built by meltwater stream through Boonville Gorge as it debouched into small lake impounded on southwest by the moraine at Rome. The Mohawk River subsequently incised a channel that swung diagonally across the valley from Westernville leaving the terrace remnants at 550-560 ft. msl., slightly above the level of Delta Reservoir.

Delta Reservoir Dam
Delta Reservoir Dam on right (W) of route. Mohawk River, incising its channel into delta and outwash deposits swung diagonally across valley from site of former village of Delta, to intrench itself at this point into Utica shale that walled the inherited bedrock valley. The steep-walled, 80-ft. deep gorge, known as The Palisade, provides a suitable dam-site for the broad, deep bedrock valley directly to the northwest is blocked by the late Cary recessional moraine at Rome. Construction of the dam in 1911 and impounding of the reservoir inundated the village of Delta, which survives only in the name of the reservoir. Through this gorge also passed the Black River Canal, traces of which can be seen beside the road directly up-valley from the dam.

State Fish Hatchery on right (W) side of road.

Griffiss Air Force Base
Bear left, continuing on N.Y. Rte. 46 at juncture with Elmer Hill Rd. Proceed south into Rome. Griffiss Air Force Base is at left (E) across Mohawk River, after Rte. 46 has become Black River Boulevard.

Narrowing Iroquois Lake Plain
Cross overpass over N.Y. Central R.R. and Erie Canal in middle of narrowing Iroquois lake plain. Less than 2 miles east is the highest elevation on the Erie Canal east of the Finger Lakes and the eastern end of the Iroquois plain. The Mohawk River having strayed from its westward-leading ancestral valley at The Palisade, has built an alluvial fan into the plain at this narrowest point. Flowing across this fan the Mohawk might as easily have drained westward, instead of eastward following the abandoned Iroquois outlet channel.

Iroquois strand
Pass entrance to Rome State School and rise obliquely across low slope of Iroquois strand.

Shallow meltwater channel
Shallow meltwater channel with threshold about 20 ft. above Iroquois strand is parallel to N.Y. Rte 365 for about 1 mile on right (NW).

Cowaselon Creek
Continue west on N.Y. Rte. 5, through Five Corners. Cross Cowaselon Creek which has cut a narrow flood plain into valley-choking glacial drift. Borrow pits at left (S), west of Cowaselon Creek, are opened in kame delta complex.

Wampsville
Village of Wampsville, location of Madison County Court House.

Canastota
Continue west on N.Y. Rte 5, following juncture with N.Y. Rte 13 in outskirts of Canastota. Samuel Champlain, French explorer fought a skirmish with Oneida Indians at village site, 6 miles south, during penetration southward from St. Lawrence settlements in 1615.

Iroquois Lake Plain.
Cross Chittenango Creek at level of Iroquois Lake Plain.

Pools Brook meltwater channel
In Mycenae, enter Pools Brook meltwater channel. For 3 miles, N.Y. Rte. 5 utilizes the low grade of this deep, transverse gorge cut by impounded pro-glacial meltwaters escaping east from Limestone Valley. Constructional topography extending into the west end of this channel indicates that principal erosion by meltwater preceded final melting of stagnant ice at channel-head near Fayetteville.

Floodplain of Limestone Creek
Continue west on N.Y. Rte. 5, through Fayetteville. Descend to floodplain of Limestone Creek at level of Iroquois Lake Plain.

Continue west
At juncture with High Bridge Rd. continue west on Rte. 5.

Descend to cross floodplain of Butternut Creek.

Syracuse Formation
Turn right (N) onto Erie Blvd. In about a mile, new construction has opened exposures in Syracuse formation on left.

C: STRATIGRAPHY AND STRUCTURE OF SILURIAN AND DEVONIAN STRATA IN THE SYRACUSE AREA
Newton E. Chute and James C. Brower

C: STRATIGRAPHY AND STRUCTURE OF SILURIAN AND DEVONIAN STRATA IN THE SYRACUSE AREA

STOP 1. Upper part of the Syracuse formation.
The contact of the Syracuse formation with the overlying Camillus shale is near the highest part of the excavation. The members exposed are as follows:
Upper dolomite member | Most of this member is exposed in the face above the bench. A distinctive porous dolomite bed, referred to in the literature as "vermicular" dolomite, is exposed in the lower part of the member. The holes of the vermicular dolomite probably were filled originally by salt or anhydrite.
Upper clay member | This member is about 10 feet thick here according to Leutze (1955, M.S. thesis, Syr. U.). It is mostly concealed under the floor of the bench and the talus debris.
Middle dolomite member | Thin- to medium-bedded dolomite. A few exposures of the upper part of this member may be seen below the bench.

STOP 2. Syracuse formation
A bed of gypsum 2 to 4 feet thick in the Lower Clay member is exposed near the bottom of the excavation behind the Victory Market and the Towne Mart. This gypsum bed is overlain by the Middle Dolomite member composed of impure thin- to medium-bedded dolomite and gypsiferous shale to the top of the excavation.

Meadowbrook cross channel
Meadowbrook Drive follows a well-defined glacial cross-channel that carried meltwater drainage eastward

STOP 3. Camillus shale.
Some of the upper part of the Camillus shale formation is exposed in small gulleys on the hillside. The rock units visible are as follows:
1.5' | Greenish gray thin-bedded dolomitic shale
6.5' | Massive greenish gray dolomitic shale with scattered quartz sand grains. This rock weathers rapidly into small angular fragments.
2' | Dolomitic thin-bedded shale that breaks into thin slabs and resists weathering better than the greenish shale above.
5' | Gypsiferous shale and gypsum? now partly leached to clay.
8'1" | Covered
2'
Massive greenish gray dolomitic shale with scattered quartz sand grains similar to the greenish shale above. This exposure is in the ditch on the east side of the macadam roadway.
Downhill, about 50 feet lower stratigraphically, 4.5 to 5 feet of greenish shale with thin beds of brownish dolomite are exposed in the bank at the uphill side of the playground behind the Washington School. These exposures probably are near the middle of the Camillus.
The Camillus of the Syracuse area seems to be unfossiliferous.

Drumlins
For the next 2 miles the route passes through a group of drumlins and bedrock exposures are scarce

Northern end of a drumlin
Between Randall Road and Guintard Road (McGee Road) the route swings west around the end of a drumlin.

Rock Cut gorge
Entering Rock Cut gorge, the largest of the cross channels, eroded by the outflow from glacial lakes in Onondaga Valley to the west. The floor of this channel is the Fiddlers Green dolomite member of the Bertie formation. It "hangs" about 140 feet above the Onondaga Valley on the west and about 50 feet above the Butternut Creek Valley on the east.
2010: What is now called "Old Stonehouse Road" used to be the continuation of Nottingham Road. It continues, on the far side of I 481, as "Rams Gulch Road" where the bridge beneath the railroad still exists. This ends at Rock Cut Road, which used to be called "The Jamesville Toll Road." The route here will get you there...

STOP 4. Rondout, Thacher, and Olney in quarry.
The quarry section is as follows:
33.5' | Olney limestone
9'
Thacher limestone
14.5' | Rondout dolomite
The Rondout and part of the Thacher are exposed in the old lower part of the quarry near the primary crusher. The main operating face is in the Olney limestone.
The Thacher here has the lithologic characteristics of the lower part of the member farther east. The contact with the overlying Olney is placed at the top of the highest zone of algal colonies and at the bottom of the lowest "drab and blue" limestone unit characteristic of the Olney.
As elsewhere in central New York, the lower Thacher exposed in this quarry is characterized by two or three zones of algal colonies and a yellow dolomite bed from about 6 inches to 3 feet in thickness. This variation in thickness appears to be due to a diastem at the top of the dolomite bed.
Subsidence structures are well exhibited in plan and section in this quarry.

STOP 5. Type section of Fiddlers Green
Turn left on the road into the Solvay Process Division's quarry property and stop at the bridge over Butternut Creek.
The Fiddlers Green dolomite has a total thickness of about 27 feet in this area. The bottom contact with the Camillus shale is exposed on the east side of the gorge several hundred feet down stream from the bridge. The top contact is not exposed, but the mudcracked beds near the bridge probably are close to the top of the member.
Ostracodes are numerous in a few thin layers, other fossils are rare.
Eurypterids have been found in the top beds in other localities.

STOP 6. Old gypsum quarries
Park at bend in road and walk 250 feet south to the roadway into the north quarry. This quarry exposes the upper part of the Scajaquada (Forge Hollow) gypsum member overlain by the Williamsville (Oxbow) impure dolomite member and the lower part of the Cobleskill dolomite.
Walk back to the entrance of the quarry and go southeast up the hill to the west side of the south quarry. Here there is an exceptionally good opportunity to observe the top of the Scajaquada member, all of the Williamsville member, and the lower half of the Cobleskill formation. A composite section of the north and east sides of the quarry is as follows:
17' Cobleskill (to top of east side of quarry)
2.5' | dolomite with numerous closely spaced fractures in the plane of the bedding. A few stromatoporoids.
10' | Stromatoporoid biostrome. Numerous partly silicified undolomitized stromatoporoids in dolomitic limestone. Some small horn corals, tabulate corals, ostracodes, and small fossil fragments. This is the only locality where this biostrome is known near Syracuse, elsewhere the Cobleskill is completely dolomitized and only a few silicified stromatoporoids remain.
4.5'
Mottled dolomitic limestone with abundant small fossil fragments and some small horn corals. This unit also is not known elsewhere in the Syracuse area.
17' Bertie formation
6' | Williamsville member - thin to medium-bedded argillaceous dolomite
11' | Scajaquada member -
| 8.5' | Thin-bedded argillaceous dolomite with 30% or more collapse breccia due to solution of interbedded salt or gypsum
| 2.5' | Top of dark brown bedded gypsum. The gypsum is reported to attain its maximum thickness of 60 to 65 feet in this area.
The location of the contact between the Williamsville and Scajaquada members is uncertain and is one of the problems to be considered at this stop.
A cross-section of a small subsidence structure is well exposed in the northeast corner of the quarry.

STOP 7. Onondaga and Manlius formations. (Lunch Stop)
The remarkable abandoned waterfall and plunge basin in this park were formed by a river that drained a glacial lake in Onondaga Creek Valley to the west when glacial ice blocked the drainage to the north.
The lip of the falls is on the Edgecliff member of the Onondaga limestone. The Nedrow and Moorehouse members are exposed nearby at higher elevations and are at the edge of the plunge basin on the north side.
This is the type locality for the members of the Manlius formation. These and other members of the Manlius, except the Thacher is covered, are well exposed along which the stairway on the south side of the plunge basin. The section here is as follows:
Onondaga limestone Clark Reservation and Jamesville
17 to 18' | Edgecliff member, 2' of sandy limestone and calcareous sandstone at base.
--- disconformity ---
Manlius limestone formation
5'9" | Pools Brook member, dolomitic limestone
19' | Jamesville limestone, numerous stromatoporoids in upper 8 feet.
3'13" | Clark Reservation oolitic limestone
9'10" | Elmwood dolomite and dolomitic limestone member
| 2'7" | Elmwood C argillaceous dolomite submember
| 2'9" | Elmwood B dolomitic limestone submember
| 4'6" | Elmwood A argillaceous dolomite submember
22' | Olney limestone to bottom of exposure

Roadcut in Manlius fm
Road cut on left in the upper few feet of the Rondout dolomite and the Thacher and Olney limestone members of the Manlius. Some unusually large algal colonies are present in the Thacher in a zone about 3 feet thick.

STOP 8. Penitentiary quarries
The two Onondaga County penitentiary quarries provide exceptionally good exposures of most of the Manlius and Onondaga limestone formations. Also a thrust fault can be seen in the upper quarry.
The stratigraphic section of the quarries is as follows:
Onondaga limestone formation
5' | Seneca limestone member (To top of quarry).
24' | Moorehouse limestone member
13' | Nedrow limestone member
23' | Edgecliff member including 4.5 feet of sandstone at the base (Springvale sandstone bed).
--- disconformity ---
Manlius limestone formation
7'3" | Pools Brook limestone member
22'2" | Jamesville limestone member
3'3" | Clark Reservation limestone member
11'4" | Elmwood member
| 3'6" | C submember
| 3'0" | B submember
| 4'8" | A submember
19' | Olney limestone member
The strata exposed in the lower quarry range from the lower part of the Olney member to the bottom 1-foot of the Pools Brook member. The main floor of this quarry is at the top of the Olney limestone with a few inches of the bottom of Elmwood A dolomite in places. The Elmwood A and C submembers are distinguished by their yellow brown weathering color, the Clark Reservation limestone by its very light gray weathering color and diagonal fractures, and the Jamesville limestone by the massive stromatoporoid biostrome that constitutes its upper half.
Most of the Pools Brook member and the overlying sandstone (Springvale sandstone bed of the Edgecliff member) are exposed in the stripped area between the two quarries. The Pools Brook is easily recognized by its thin bedding and sparseness of fossils. The Springvale sandstone is brown and contains scattered black phosphatic nodules.
The upper quarry is entirely in the Onondaga limestone. Most of the floor is on the top of the Springvale sandstone. On the downthrown side of the thrust fault, at the north side of the quarry, the floor is in the lower part of the Moorehouse limestone member. The middle and upper parts of the Moorehouse member are most accessible for examination on the downthrown side of the thrust fault at the north side of the quarry, where loosely coiled cephalopods of the Halloceras bed are exposed on the floor. Oliver (1954, G.S.A. v. 65) designated this quarry as the type locality of the Moorehouse member. He derived its name from Moorehouse Flats nearby. The Seneca member is poorly represented in the quarry. All but a few feet has been eroded.
The Edgecliff member contains numerous rugose and tabulate corals and much crinoid debris including some unusually large columnals. It is most easily seen at the west end of the north side of the quarry. The Nedrow member also is most accessible here.
The reverse fault on the north side of the upper quarry strikes about N 70 W, dips about 20 degrees south, and has a throw of 31 feet. It is complicated in places by multiple slip planes, drag, and crushing. Small veins in north-south joints near the fault contain calcite, dolomite, fluorite, quartz, and a solid hydrocarbon. These are best seen in the Olney limestone of the lower quarry.

STOP 9. View to the South
View to south of the stripped surface on the Onondaga Limestone which forms a prominent bench about 150 feet above the bottom of Butternut Creek Valley. The Marcellus and Skaneateles formations of the Hamilton Group form the steep slopes to the southeast.

STOP 10. Coral Bioherm in Onondaga Limestone
Taylor Road crosses a coral bioherm here. Most of the exposures are in the wooded tract on the west side of the road. This is the only bioherm known in the Onondaga Limestone in the Syracuse area. Usually these bioherms start in the Edgecliff member and, if thick enough, extend upward into higher members. In the absence of exposures of the adjacent limestone, it is not possible to determine the stratigraphic range of this bioherm, but it appears to extend well up into the formation.

Thrust fault
A thrust fault, which strikes about N 70 W, dips about 20 degrees south, and has a throw of 42 feet, crosses Route 173 near this road junction. Formerly it was exposed in one of the old quarries that are now filled. Present exposures east of the road junction show the Onondaga and Manlius limestones offset by the fault.

Onondaga outcrop
Outcrop of Onondaga limestone at edge of road on left.

Subsidence structure
Subsidence structure in Onondaga limestone in field on left. Exposed beds have an anomalous dip west because of this structure.

Smoky Hollow cross channel
Road crosses west end of Smoky Hollow cross channel at an altitude of about 780 feet. This is the southernmost of the well-developed cross channels eroded between Onondaga Valley and Butternut Creek Valley by the outflow from glacial lakes in Onondaga Valley. The channel was eroded in Marcellus shale down to the more resistant Onondaga limestone.

STOP 11. View of Onondaga Creek Valley
Some of the topographic, glacial, and stratigraphic features of this part of the valley will be pointed out at this stop.

Onondaga limestone roadcuts
Turn left (S) on Kennedy Road. Road cuts on the new divided highway (Route 81) to right are in the Edgecliff and Nedrow members of the Onondaga limestone. The road cuts on Kennedy Road are in the Moorehouse member and the top few feet of the Nedrow member.

STOP 12. Top of Onondaga and thrust fault
STOP 12. Top of the Onondaga limestone and Union Springs shale displaced by a small thrust fault. The upper 8 feet of the Onondaga limestone and about 10 feet of the Union Springs shale are exposed on the side of the deep drainage ditch on the east side of the road. Exposures of the top contact of the Onondaga such as this are rare. At the south end of the drainage ditch a thrust fault with a throw of about 5 feet cuts the top of the Onondaga but is absorbed in the Union Springs shale above by complex crumpling and jointing.

STOP 13. Manlius and Onondaga fms.
The stratigraphic units exposed in the road cut are as follows:
Onondaga limestone formation
11'6" | Moorehouse limestone member (to top of exposure)
11-12' | Nedrow limestone member
12'8" | Edgecliff limestone member
--- disconformity ---
Manlius limestone formation
10' | Pools Brook limestone member
18' | Jamesville limestone member
4' | Clark Reservation limestone member
9'10" | Elmwood dolomite and dolomitic limestone member
| Elmwood C (only the top few inches exposed)
The lowest part of the section is at the north end of the cut where the top few inches of Elmwood C, the Clark Reservation, and the Jamesville are exposed.
This stop provides an opportunity to compare the stratigraphic units with the same units seen at the Penitentiary quarries (stop 8) 4 miles northwest. Most of the units are similar, but one significant difference at this stop is the absence of the Springvale sandstone bed at the base of the Edgecliff member and another is the presence of a bed with stromatoporoids and favositid corals at the top of the Pools Brook member. This bed has a small erosion surface at its base suggesting that it might correlate with the Bishop Brook limestone exposed on the hill northeast of Manlius, which is in a similar stratigraphic position and also has an erosion surface at its base. However, the bed appears to resemble the Jamesville more closely than the Bishops Brook both faunally and lithologically.
Inclined joints are well developed in the Nedrow member on the south side of the exit road from Route 81. Many of these are limited to certain beds and end upward against prominent shaly partings. They also are numerous in the Manlius at the north end of the road cut where the beds are slightly arched.

STOP 14. Type locality of the Nedrow member.
Indian Reservation quarry in the Onondga limestone, the type locality of the Nedrow member. This quarry formerly was worked for building stone.
The stratigraphic units exposed in the quarry are as follows:
Onondaga limestone formation
15'19"' | Seneca limestone member (To top of quarry).
18'6" | Moorehouse limestone member
11-12' | Nedrow limestone member
12'0" | Edgecliff limestone member (base not exposed).
The main floor at the south end of the quarry is at the top of the Edgecliff member. The south face exposes the Nedrow, Moorehouse, and Seneca members. The Tioga bentonite bed (8" to 9" thick), which Oliver (1954, Bull. G.S.A., v. 65) uses as the boundary between the Moorehouse and Seneca members, can be seen in the upper part of the face where it forms a reentrant a few inches above a 4-inch layer of black chert.
The best fossil collecting is on the main floor of the quarry where brachiopods, corals, bryozoa, and crinoid debris, including segments of unusually large columnals, are abundant.
Climb up the south side of the quarry to observe the Tioga bentonite and the Seneca member at the top. A zone of pink chonetid brachiopods is exposed about 2 feet below the highest beds at the edge of the stripping.
Walk east to the fence on Route 81 to observe the Union Springs shale and the Cherry Valley limestone exposed in a new road cut.

Marcellus Shale
Ravine in Marcellus shale on left a short distance west of the County Home.

STOP 15. Quarries in Manlius and Onondaga limestones
Split Rock quarries in the Manlius and Onondaga limestones. Park in old part of quarry at end of road and walk east into the easternmost quarry in the Manlius. The Edgecliff member of the Onondaga limestone can be seen in this quarry to rest disconformably on Elmwood A bed of the Elmwood member. The 33 feet of limestone between the Elmwood A bed and the Rondout dolomite exposed on the floor of the quarry, is considered to be the Olney member of the Manlius formation by Rickard (1962, N.Y.S. Mus. Bull., 386). The bottom 5 feet of this limestone, however, has beds characteristic of the lower part of the Thacher limestone member to the east. These beds will be examined in an attempt to evaluate their significance in resolving the problem of the "disappearance" of the Thacher. End of Trip

D: GEOMORPHOLOGY OF THE NORTH MARGIN OF THE APPALACHIAN UPLANDS NEAR SYRACUSE
Surficial Geology of the Syracuse Field Area
Ernest H. Muller

Start

Meltwater channel
Cross meltwater cross channel utilized as corridor by N.Y. Central R.R., Erie Boulevard and formerly by Erie Canal. Channel is below main Iroquois lake level and auguring shows peat and marl over fine sand and clay, underlain by coarse alluvium, suggesting rise of Iroquois waters into meltwater channel, followed by swamp development in poorly drained basin left after Iroquois extinction.

Sharp Slope on Syracuse Formation
Crossing Erie Boulevard at traffic light, proceed S on Thompson Rd. rising onto sharp slope developed on Syracuse Formation.

Thin till
Turn right (W) onto Salt Springs Rd. over drumlinized upland developed on thin till over Syracuse shales.

Meadowbrook Meltwater Channel
Continuing SW on Meadowbrook Drive, follow meltwater channel to its end in "t-intersection"

Rock Cut road
On left, railroad cut exposes section in Fiddlers Green dolomite which forms floor of flat-bottomed, steep-walled Rock Cut or Railroad Channel leading east from this point. With its threshold at 550-ft. this is one of several major meltwater channels which controlled eastward escape of water from lakes impounded in central New York through valleys, between the northward receding margin of the ice sheet and the plateau divides to the south.

Rise at Elmwood Formation
In .2 mile rise sharply over scarp developed on Manlius Group, with Elmwood Formation exposed at left near bench edge.

Onondaga trough
Descend to floor of Onondaga trough over strata of Manlius Group. Cross U.S. Rte. 11 (Salina St.) and Onondaga Creek.
Near Onondaga Lake, about 3 miles north, the bedrock floor of Onondaga trough is 417 ft. below the surface or about 25-ft. below sea level.

Dorwin Springs Bench
Near Dorwin Springs, road ascends onto gravel bench, dissected and with low constructional topography. At right (W) massive Onondaga Limestone supports narrow benches on the valley wall. At left (E) the gravel bench is about at level of the threshold of Rock Cut Channel on opposite side of the valley.

STOP 1 Saunders Gravel Pit
Discussion of character and structure of gravel bench in its relationship to Onondaga Trough history

Cross Commissary Creek
Cross Commissary Creek which dissects end of 560-ft bench

Bench at 620 ft
Ascend onto bench at approximately 620 ft.

Rise to 720 ft bench
Continue west on Johnny Cake Rd., leaving N.Y. Rte 80 at Griffins Corners. Rise to level of 720-ft. bench. Cross Onondaga Hill Rd. then descending toward Nichols Corners, note sand and gravel exposures on left (S).
2009: Perhaps Rte 80 used to go through South Onondaga, and Tanner Road used to be called Johnny Cake Road?

Nichols Corners
At Nichols Corners, turn right onto Cedarvale Rd. Just before turning note red clay till in stream bank at left (S).
Proceeding NW on Cedarvale Rd. follow Cedarvale meltwater channel. Note constructional topography due to deposition from stagnant, debris-littered ice on slope at right (NE).

Benches at 680 and 800 ft
Turn left (S) onto Amber Rd. and proceed across gravel bench at 680 ft. msl, with sharp rise to bench above 800 ft. msl on right.

STOP 2 Cedarvale Gravel Quarry
Composition and structure of the gravel bench in relationship to Cedarvale Channel and Onondaga Trough history

View of Delta Remnant in distance
Continuing on Amber Rd. turn sharply south and continue ascent. Note flat-topped mesa-like delta remnant on left (E) at 800 ft. msl. near South Onondaga.

Navarino Channel
On right (W) note head of sizable meltwater channel, the Navarino Channel by which glacial meltwaters escaped southward into basin of Otisco Lake.
Continue through area of moderate constructional topography deposited by stagnant ice. Note Navarino Channel paralleling Amber Rd.

Head of meltwater channel
At Joshua Corners, on right (SW) note level swampy area at head of minor meltwater channel which contributed to complex Amber delta deposited into a predecessor of Otisco Lake, 3 miles SW.

Bioherm in the Spafford Shale
Turn right (S) at Lords Corners, onto Lords Hill Rd., N.Y. Rte. 80. Ascend over Hamilton section, near summit passing biohermal zone in Spafford Shale, rich in rugose corals, overlain at top by Owasco shale. When not tar-concealed by Highway Department these gullies afford fine collecting.
Descend and cross open, marshy east-west valley. To left (E), Fall Ck. flows to Rattlesnake Gulf. To right (W) stagnant ice features comprise divide between 0tisco and Onondaga drainage basins.

Glacial Trough
Descend SE along trough like glacial furrow occupied by headwaters of Onondaga Creek.

Tully moraine belt
Cross Onondaga Creek. Enter complex Tully moraine belt where minor ridges project into this tributary trough with curvature convex to the northwest. At Fellows Falls, Onondaga Creek drops with hanging and barbed juncture into Onondaga trough, in this area called Tully Valley. To the left ahead (NE) local reIief exceeds 1250 ft. from upland to trough floor on proximal (northern) flank of massive Tully (Valley Heads) moraine. The abrupt proximal border and gently graded distal slope of this moraine is characteristic of valley-blocking moraine loops of this system in central New York.
Seismic refraction profiles suggest that the unconsolidated valley fill in mid-trough opposite Fellows Falls may be 400 to 500 ft. thick with the bedrock floor at 300 to 400 ft. msl.

STOP 3 Green Lake (Tully Lakes)
Examination of features and materials of pitted outwash plain. Discussion of significance in terms of Valley Heads and Onondaga trough glacial history.
Proceed east toward Tully.
2009: With Interstate 81 in the way, Lake Road no longer continues East here. The path gets us to Tully just the same.

Kame and kettle
Leave N.Y. Rte. 80. Continue south along west wall of Onondaga trough. On right Moscow shale exposed in trough wall. On left, Tully moraine with strong kame and kettle topography. Southward the kames diminish in relief and grade into kame terrace. Crooked Lake at left occupies a compound kettle.

Leave outwash plain
Leave outwash plain and ascend onto upland developed on Ithaca and Sherburne Formations.

Kettle Dotted Outwash Plain
Turn left (E) across kettle-dotted outwash plain. Stagnant ice of the Tully ice tongue extended about one mile south of this route to an "advance Valley Heads" position, before receding 3 miles north to the massive "main Valley Heads" position. The position of this moraine complex has been ascribed to bedrock topographic control at the former drainage divide. Seismic data at Tully Lake suggest depth to bedrock of about 225 ft.

Enter distal margin of Tully moraine
Enter distal margin of Tully moraine. For next 2 miles constructional topography is strong, diminishing gradually on proximal edge of moraine.

Butternut Creek trough
At traffic light in Lafayette, turn right (E) onto U.S. Rte 20, Cherry Valley Turnpike. In.2 mi. turn left (N) onto Lafayette Rd. The gently curving, partly drift-filled trough of Butternut Creek is visible ahead on right, with U.S. Rte 20 swinging across at Big Bend.
Crossing the upland, bedrock ridges, such as Irish Hill on right (E) are streamlined, gently molded and parallel to lineation of drumlins a few miles to the north.

Drumlin field
Pass Bull Hill Rd. Drumlins on left (W) are composed of bouldery, lime-rich lodgment till. Alignment is N5W, as compared to N30W in outskirts of Syracuse. Artificially impounded Jamesville Reservoir on right (NE) ahead.

STOP 4 Horseshoe or Loop Channel
Consideration of nature of Smoky Hollow and the Loop umlaufberg, and of their significance with respect to late Cary glacial recession.
Continue north on Barker Hill Rd. Descend onto terrace that blocks upstream end of the Loop. Roadcut at the terrace edge exposes rhythmically laminated lake sediments. The eastern arm of the Loop contains kame gravels.

Smoky Hollow
Cross Smoky Hollow, part of a major meltwater channel with bedrock floor just below 800 ft. msl. Sharply incised into non-resistant Hamilton shales, this outlet may have controlled drainage of impounded waters in Onondaga trough at level of highest delta in Cedarvale Channel. Note that drumlin on right (E) is truncated by wall of Smoky Hollow, indicating that channel cutting postdated final drumlin moulding. Continue north on Barker Hill Rd.

Descend onto Onondaga bench
Descend from drumlinized Hamilton upland onto channeled Onondaga bench.

STOP 5 Clark Reservation
Examination of features due to erosion by glacial meltwater, solution by underground water and joint control as developed near Green Lake and along south wall of Rock Cut Channel. Discussion of significance in terms of interpreted history of glacier recession.
Return to N.Y. Rte 173 and turn left (E) toward Jamesville.
On left (N) of road note deep channel leading east from Green Lake to Butternut trough.

Fiddlers Green Dolomite
Cross tracks and turn left (N) onto Jamesville Rd. which parallels Butternut Creek. Below falls, in .2 mi. Butternut Creek exposes type Fiddlers Green dolomite.

Rock Cut view and Rams Gulch
At fork bear right, continuing N on Jamesville Rd. Descend to floor of Butternut trough. Cross Butternut Creek and the eastern or outlet end of Rock Cut Channel is visible on left (W), notched by narrow post-glacial Rams Gulch.

Alluvial Plain of Iroquois Lake
Recross Butternut Creek on alluvial plain at approximate level of Iroquois Lake which may have inundated lower end of valley as a consequence of isostatic upwarp northward. Rise onto trough wall and proceed north.

E: STRATIGRAPHY OF THE HAMILTON GROUP IN THE SYRACUSE AREA
Newton E. Chute and James C. Brower

E: STRATIGRAPHY OF THE HAMILTON GROUP IN THE SYRACUSE AREA

View of hills in the Marcellus and Skaneateles fms ahead.

Drumlin and scarp
Drumlin on the left and a scarp in the Manlius and Rondout formations on the right.

Entering Rock Cut Channel.
This large cross channel was cut during the recession of the glacial ice by the drainage from a glacial lake in Onondaga Valley to the west.
2010: What is now called "Old Stonehouse Road" used to be the continuation of Nottingham Road. It continues, on the far side of I 481, as "Rams Gulch Road" where the bridge beneath the railroad still exists. This ends at Rock Cut Road, which used to be called "The Jamesville Toll Road." The route here will get you to the next stop...

Cobleskill and Roundout fms
Road cut on right in the Cobleskill and Rondout dolomite formations. The Cobleskill is thicker bedded and is composed of purer dolomite than the Rondout.
DEC site 416

Bridge over the D. L. & W. Railroad.

Stone crusher building
Junction of Jamesville Toll Road and Jamesville Road. The stone crusher building of the Solvay Process Division of the Allied Chemical Corporation can be seen on the hillside to the left.

Edgecliff member
Exposure of the Edgecliff member of the Onondaga limestone on the left near top of grade.

Cherry Valley member
Small exposure of the Cherry Valley limestone member of the Marcellus formation in road cut on left near top of rise.

View of the Solvay Process Division Quarry on left.

STOP 1. Monocline in the Onondaga
STOP 1. Monocline in the Onondaga limestone and exposures of the Union Springs shale, Cherry Valley limestone, and Chittenango shale members of the Marcellus formation.
Walk south up the stream for about 500 feet to where the top beds of the Onondaga limestone exposed in the stream bed dip northward due to the presence of a monocline that strikes about N 70 W. This monocline probably grades into a thrust fault in the Solvay Process Division's quarry. Solution-widened tension joints are well-developed in the limestone on the monocline.
Continue up the stream to where it forks. About 15 feet of Union Springs shale and about 3 feet of Cherry Valley limestone are exposed at a small waterfall on the left branch not far from the fork. The Union Springs consists of black shale with numerous thin beds of black limestone. Styliolina fissurella, a small mollusk shaped like a pencil point, is common in the shale of the upper part of the member. The Cherry Valley limestone forms the lip of the falls. This member is noted for cephalopods and one or more may be seen in the stream bed at the top of the falls. The basal few feet of Chittenango shale, exposed in the stream bank above the falls, contains one or more thin beds of black limestone. Numerous styliolina fissurella can be seen on the bedding surfaces of some of the shale.

Small waterfall on the left branch not far from the fork

STOP 2. Chittenango and Cardiff shales.
This shale is quarried by the Alpha Portland Cement Company for use in cement manufacture at its Jamesville plant. The upper bench is in the upper 40 to 50 feet of the Chittenango shale member of the Marcellus formation.
Although these shales are similar in appearance, they can be distinguished easily by their streaks. The Chittenango shale, because of its relatively high content of carbonaceous matter, streaks brown when scraped by a hard object such as a geologic hammer, whereas the Cardiff streaks light gray. Examination of drill core from several test holes has shown that the change in color of the streak takes place within a vertical interval of 3 feet. The contact is placed where, in going downward, the streak becomes distinctly brown. Located this way, the contact is near the top of the lower face, 5 to 6 feet above the upper layer of large septarian concretions.
Many of the septarian concretions in the upper part of the Chittenango are several feet across. The Cardiff shale on the other hand has only a few concretions and these are seldom more than 6 inches in diameter. The cracks within the septarian concretions commonly contain calcite, ferroan dolomite, and white, platy barite. Small crystals of barite with some pyrite also coat joint surfaces in the shale in places.
Fossils are sparse or lacking in most of the Chittenango and Cardiff shales, but one or more zones near the top of the Chittenango contain numerous carbonized plant remains and a few fish scales, fish body plates, pyritized straight cephalopods, and small brachiopods. Because the shale tends to break down into small pieces after exposure for a few months, the success of fossil collecting depends on the recency of quarrying in the fossil zones.

Centerfield member in road cuts.

STOP 3. Butternut member
Road cuts and small quarry in the upper part of the Butternut member of the Skaneateles formation.
About 40 feet of the upper Butternut is exposed in the small quarry and road cuts nearby. Most of the exposure consists of shale with thin siltstone layers and silty shale that increase upward. The top 5.5 feet in the quarry is siltstone. This siltstone and the silty shale below contain some brachiopods particularly Leiorhynchus sp. The lowest beds exposed in the road cut are poorly fossiliferous shale that splits into thin flat pieces "paper shale", a characteristic of the shale of the middle and lower parts of this member.

STOP 4. Platform of Staghorn Point biostrome.
Stop opposite the yellow brick house. Walk about 100 feet up the hillside on the west side of the road to exposures of siltstone strata that form a bench on the hillside. This is the siltstone platform on which the Staghorn Point coral biostrome was formed. It is about 50 feet above the base of the Otisco member of the Ludlowville formation and is an important horizon marker in Syracuse area. The exposed section here is as follows:
Ludlowville formation - Otisco member
8" | siltstone bed with numerous molds of corals in bottom 2 inches
3'0" | covered
4'10"
siltstone platform with several thin discontinuous fossil-rich layers. Base not exposed but total thickness of siltstone probably about 6 feet.

STOP 5. Delphi Station and Pompey members.
Observe the upper beds of the Pompey member exposed near the top of the falls. Walk right on path along the edge of the gorge to where the falls can be observed.
The top 60 feet of the falls is Cooper's (1930, Am. J. Sci. v. 19) type section of the Pompey member. The resistant siltstone beds that form the lip of the falls are his  Eunella-Nyassa zone that marks the top of the Pompey, distinguished by the presence of  Eunella lincklaeni, Athyris cora, and  Nyassa arguta. The lower part of the falls exposes the upper part of the Delphi Station member. The Mottville limestone member which underlies the Delphi Station member is exposed a moderate distance downstream from the falls.
DEC sites 347, 348

Small shale quarry
Small shale quarry in the Butternut member of the Skaneateles formation on the right side of the road.

STOP 6. Pompey and Delphi Station members
Road cut in the Pompey and Delphi Station members of the Skaneateles formation.
This cut exposes about 115 feet of the Pompey and Delphi Station members. The 8 feet of siltstone at the top of the cut is Cooper's Eunella-Nyassa zone that marks the top of the Pompey, the same unit that forms the lip of Pratts Falls. This siltstone grades downward into gray shale.
The contact between the Delphi Station and the Pompey members is not easily located and is one of the problems to be considered at this stop.

Butternut member
Road cut on the left in the Butternut member of the Skaneateles formation on road connecting Routes 81 and 20.

STOP 7. Lower part of the Centerfield
Lower part of the Centerfield calcareous siltstone member of the Skaneateles formation.
Walk a short distance north from Route 20 to the waterfalls on the lower part of the Centerfield. The deep ravine below the falls is in the Butternut shale member of the Skaneateles formation.

STOP 8. Centerfield member.
Walk southeast about 200 feet to the stream where the Centerfield member forms a waterfall. Most of the Centerfield is exposed here, and the upper part with calcareous concretions is accessible for close observation. The gradational nature of the bottom contact of the Centerfield with the Butternut member can be seen on the side of the falls. The total thickness of the Centerfield is not closely determined in this area, but may be about 30 feet.
One of the noteworthy features here is the joint controlled cleft at the top of the falls through which the stream flows.

STOP 9. Joshua Coral Reef
Joshua Coral Reef in the Otisco shale member of the Ludlowville formation.
This is the famous Lords Hill locality described by W. A. Oliver, (1951, Amer. Jour. Sci., p. 705-728). The coral bed is estimated to be as much as 50 feet thick in this area and to be about 90 feet above the bottom of the Otisco Member. The exposure was much better before the road ditches were coated with blacktop, but some of the corals can still be seen and collected. According to Oliver, the most common genera of rugose corals here, in order of abundance, are: Cystiphylloides, Siphonophrentis, Bethanyphyllum, Heliophyllum, and Heterophrentis. In addition the colonial rugose form Eridophyllum and several species of Favosites are present.

Ivy Point siltstone member
Small exposures of the Ivy Point siltstone member of the Ludlowville formation on both sides of the road. The Ivy Point forms benches in this area.

STOP 10. Owasco, Portland Point and Windom members
Road cut in the Owasco member of the Ludlowville formation, and the Portland Point and Windom members of the Moscow formation.
Moscow formation
1'6" | Windom shale member (to top of exposure)
9'1" | Portland Point member
| 7'6" | shale and thin interbedded fossil rich limestone layers
| 1'7" | impure limestone, fossiliferous
Ludlowville formation
2'3" | Owasco siltstone member
2'0" | Spafford shale member (to base of exposure)
The Portland Point member, according to Cooper (1930), consists of 1 foot of crinoidal limestone overlain by 8.5 feet of calcareous shale with interbedded thin layers of limestone. At this locality the basal limestone is a little thicker, and thin beds of fossiliferous limestone are present in the overlying shale for about 7.5 feet above the limestone. Because of the indefiniteness of the position of the upper contact, the amount of Windom present in this exposure, if any, is uncertain.

STOP 11. Tully limestone.
Small exposure of the upper part of the Tully limestone on the south side of the road opposite a red barn. Walk down the hill to the east a short distance and turn into the old quarry in the Tully limestone on the north side of the road. The top 5 feet of the quarry is the West Brook member below which is 10 feet of the Apulia member. The contact between them is placed at the bottom of the nodular limestone of the West Brook. The Tinkers Falls member is not exposed. Fielding (1956, MS thesis, Syracuse Univ.) estimates the total thickness of the Apulia member to be 18 feet and the West Brook member to be 9 feet in the South Onondaga quadrangle.
The Apulia member contains crinoid fragments, ostracods, and brachiopods particularly Hypothyridina venestula. The coral Lopholasma is characteristic of the West Brook member. In addition, Fielding (1956) reported finding Metriophyllum tullium, Elytha fimbriata, Phacops rana, Tornoceras uniangulare and crinoid fragments.

STOP 12. Windom member of Moscow fm.
About 20 feet of the top part of the Windom shale member is exposed in the road cut on Kingsley Road. The shale becomes silty near the top of the exposure and is sufficiently resistant to have formed a bench about 500 feet wide. A few small calcareous concretions can be seen in this exposure and enough pyrite is present to cause considerable limonite staining. Brachiopods, pelecypods, and trilobites are present, but are not abundant. End of trip.

GUIDEBOOK TO FIELD TRIPS
Philip C. Hewitt and Leo M. Hall
Editors
Contributing Authors
Donald W. Fisher*
Yngvar W. Isachsen*
Philip C. Hewitt
Robert G. LaFleur
William E. McClennan
Harold Nilsson
Host
UNION COLLEGE
Schenectady, N. Y.
April I-May 2, 1965
* Published by permission of the Assistant Commissioner, New York State Museum and Science Service.

A: MOHAWK VALLEY STRATA AND STRUCTURE
Saratoga to Canajoharie
by Donald W. Fisher
State Paleontologist
New York State Museum & Science Service
"The crust of our earth is a great cemetery, where the rocks are tombstones, on which the buried dead have written their own epitaphs".
Agassiz

A: MOHAWK VALLEY STRATA AND STRUCTURE

Normanskill Graywacke
Outcrop of Middle Ordovician Normanskill Graywacke and Shale along east (northbound) lane. This is the westernmost extent of a large area of Normanskill, interpreted as a thrust outlier of the Taconic Allochthon or as a north-trending anticline protruding from beneath a cover of younger rocks.

Crossing Mohawk River
These dual tied-arch bridges won an award in 1958 for their design.

Former channel of the Mohawk River.
Crossing former channel of the Mohawk River. To the east, Round Lake occupies a portion of this now abandoned channel.

Snake Hill Shale
Long exposure in Middle Ordovician Snake Hill Shale, a dark gray silty facies of the Canajoharie Shale of the Mohawk Valley.

STOP 1. Lester Park
This is the type section for the Late Cambrian Hoyt Limestone, noted for its biostromal reefs of colonial algae called  Cryptozoon (see Fig. 9, Plate 1). The lowest reef has been planed by glacial erosion revealing the algal heads in horizontal section; a higher reef, in the recently enlarged road cut, exhibits a vertical section of  Cryptozoon. A still higher reef in the abandoned Hoyt Quarry displays a reef of algal mats rather than heads. Between the lowest and middle reefs is a coarse-grained dolomitic limestone with oolites and trilobite fragments; the genera  Prosaukia, Saratogia, Plethometopus, Plethopeltis, and  Dikellocephalus have been collected here, thereby establishing a Trempealeau age.
DEC Links 1 2 3

Petrified Gardens and Old Quarry
On left (east.) is entrance to Petrified Gardens, a privately owned exhibit of the Hoyt Limestone and its  Cryptozoon reefs. On right is old quarry in the Ritchie Limestone, either a local facies of the Hoyt or a slightly younger unit. Its rare fossils (the gastropod  Rhachopea) are not diagnostic. An east-trending normal fault separates this quarry from Lower Ordovician Gailor Dolomite on the downthrown, southern side.
DEC Links 1 2 3

STOP 2 ROCK CITY FALLS stratigraphic section.
In addition to studying several rock units here, there is a fine display of the Lower Ordovician-Middle Ordovician unconformity (disconformity) between the older Gailor Dolomite forming the face of the falls and the Amsterdam Limestone. The falls marks a fault-line scarp, upthrown on the west. The downthrown block exhibits Middle Ordovician Larrabee Limestone beneath the road bridge, some 70 feet lower than in the quarry on the upthrown block.

Glacial features
Morainal pond on north side of road; extensive cover of glacial sand and gravel in this region.

STOP 3
Basal Paleozoic cobble conglomerate consisting of quartz cobbles, derived from a Precambrian quartzite atop the hill to the north, in a siliceous, pyritic matrix. Midway in the exposure is some coarse textured, bedded, quartzose sandstone. This entire unit has been called Potsdam in the past because of its basal position and subjacency to the Theresa Formation, which crops out along the road to the west. Lithologically it is atypical for Potsdam; it seems to be a talus deposit, probably formed at the base of a sea cliff in Late Cambrian time., Precambrian biotite-gneiss may be uncovered by digging beneath this basal Paleozoic conglomerate.

Theresa Formation
Road cut in Theresa Formation, a unit with alternating quartzose dolomites and dolomitic sandstones with occasional golf-ball size quartzite pebbles.

Fault-line scarp
Climb fault-line scarp; this is the northern extension of the Hoffmans Fault, the most easterly of the Mohawk Valley normal or step faults.

Cliff of Little Falls Dolomite, upthrown side
Intersection with West Galway Road, proceed straight ahead. Cliff of Upper Cambrian Little Falls Dolomite on upthrown side of fault parallels road on the right.

Larrabee Limestone, downthrown block
Middle Ordovician Larrabee Limestone along road, on right, opposite old cemetery. This is the eastern downthrown block. Scarp veers southwestward.

There are two normal (gravity) faults here, both downthrown on the east with a small fault block (horse) caught between them (see Fig. 11, Plate 1). The eastern block shows steep east-dipping Larrabee Limestone with included round pebbles of a black, fine-grained, limestone (Amsterdam?) dragged against slightly westward dipping fine-grained, tan-gray, white weathering Lowville Limestone. The Lowville within this horse is overlain directly by the gray, coarse-grained Larrabee Limestone; the Amsterdam Limestone is missing from its accustomed position between the two in the Lower Mohawk Valley. Like all other horses observed by me, this one dips north or reverse from the regional dip. The west block exposes nearly horizontal Little Falls Dolomite.

Hoffmans fault
LEAVE horse, continue west on town road, crossing main branch of Hoffmans Fault.

View of Mohawk Valley to the SW
Atop hill, good view of Mohawk Valley to the southwest, looking down dip.

Underlain by Little Falls Dolomite
This region underlain by Little Falls Dolomite.

Little Falls Dolomite
Long road cut in Little Falls Dolomite (both sides of road). Quartz crystals and chert are absent here although we are less than 50 feet below the Tribes Hill Fm.

Pre-glacial valley
Lower area to west is the course of a pre-glacial valley, tributary to the Mohawk.

Hoffman's Fault
Straight ahead at intersection with West Glenville Road. Outcropping of thick-bedded, coarse-grained, light gray Larrabee Limestone (with "Shoreham" fossil  Cryptolithus) on lumpy-bedded, fine-grained, dark gray to black Amsterdam Limestone on southwest corner. This is the fault-line scarp of the Hoffmans Fault.

WOLF HOLLOW and LUNCH Park on left,horse on right. The road and stream follow the fault trace of the Hoffmans Fault which, here, has a vertical displacement (throw) of at least 1000 feet and very probably as much as 1600 feet (see Figure 8). The downthrown (east) block exposes Middle Ordovician Schenectady Graywacke and Shale in the southern part of the Hollow and Canajoharie black shale in the northern part. The upthrown (west) block shows the Lower Ordovician Gailor Dolomite forming the impressive cliff. A small horse on the west side of the road of "Shoreham" Limestone and Canajoharie Shale dips north. Wolf Hollow well exemplifies the role exerted by faults in controlling drainage.

Fault exposure
Sharp left curve. Schenectady Graywacke and Shale dragged at a 40° angle, diminishing to less than 5° at eastern limit of exposure, some 500' distant.

Cliff
Long high road cut begins where Toureuna Road joins NY 5; lower 40' is Little Falls Dolostone and the remainder of the cliff is Gailor Dolostone. A small hill atop the cliff exhibits Lowville, Amsterdam, Larrabee, and "Shoreham" Limestones and Canajoharie Shale in their normal stratigraphic positions. Thus, the stratigraphic succession can be demonstrated conclusively in this single section.

Road cut on NY 5 at railroad overpass. The two middle members of the Tribes Hill Formation are exposed here;the massive Wolf Hollow dolomitic calcilutite (fine-grained limestone) is in contact with the thin bedded Palatine Bridge dolomitic shale and quartzose calcisiltite (medium grained limestone) and calcilutite. Note the white and buff fretwork weathering of the Wolf Hollow member with the buff dolomite in relief. The Palatine Bridge member is lighter colored and more quartzose and pyritic. A single dolomite bed, 2 1/2 feet thick, in the lower part of the Wolf Hollow member can be traced throughout the Valley; it is a bluish-gray, medium-textured dolostone with pockets (vugs) of dolomite crystals. Fossils are scarce in both members. The Wolf Hollow member has a molluscan fauna of large, loosely coiled gastropods and straight or gently curved ellesmeroceroid and clarkoceroid cephalopods. In contrast, the Palatine Bridge member has an arthropod (trilobite) and brachiopod fauna. Both faunas indicate an Early Canadian (=Tremadoc) age.

Fort Johnson
Baronial home of Sir William Johnson built in 1749 on northwest corner.

Tribes Hill Fault
Cross Tribes Hill Fault, upthrown on west.

Roadcut with weathered rock
On north side of NY 5 is a cut in the same portion of the section viewed at the previous stop. Note the change in appearance owing to longer weathering (exposed initially in 1958). When first revealed, there was a two-foot iron oxide zone at the top of the Palatine Bridge member; this corresponds to the two-foot dolomitic shale zone at the previous stop.

Parking area
Parking area, splendid view of Mohawk Valley with Schoharie Valley in distance.

On north side of NY 5, Middle Ordovician Canajoharie Shale, here more of a calcareous argillite which is typical of the lowest 200' of the formation, has graptolites (See Figure 13, Plate 1) in the upper few feet of the exposure. These extinct animals, excellent guide fossils for subdividing the Ordovician and Silurian Periods, are thought to have been floaters (plankton) and, thus, achieved wider distribution in a relatively short period of time as compared to bottom dwellers.

STONE RIDGE This is a critical section in deciphering structure and Ordovician stratigraphy in the Valley.
The three upper members of the Tribes Hill Formation are exposed (upper Palatine Bridge and Wolf Hollow in Van Wie Creek to the west of Borden Road and Fonda member in road ditch and road cut). The Chuctanunda Creek Dolostone is missing due to erosion. This is a superb example of a disconformity (See Figure 7). The older Tribes Hill Formation has been subjected to subaerial erosion and the crevices at its summit are filled, in places, with white weathering Lowville Limestone with vertical worm borings. Lumpy bedded limestone (Amsterdam or Larrabee ?) occurs above; the fossils are not diagnostic in distinguishing which Middle Ordovician unit crops out in this cut. Further up Van Wie Creek, undoubted Larrabee and "Shoreham" Limestones are overlain by Canajoharie Shale. In the road ditch a coarse grained limestone (calcarenite) with glauconite yields abundant fossils. Most of these are stained with iron oxide and are water-worn. Gastropods are abundant but the unusual pelecypod-like arthropod,  Ribeiria, (See Figure 14, Plate 1) exceeds all others in numbers. Trilobites, ellesmeroceroid cephalopods, and brachiopods round out the major faunal elements. Rare calyx plates of cystids and conodonts complete the known fauna.

Fonda wash plain across river
Note flat topped Fonda wash plain across river. This is an Ice Age delta consisting of water-laid gravels and sands which extends north for 4 1/2 miles and west for 3.5 miles from Fonda to the Noses Fault.

NOSES FAULT and ANTICLINE ? NONCONFORMITY or FAULT CONTACT ?
Park next to barn at intersection of Anderson and Currytown Roads, walk across bridge over Yatesville Creek through private property to rock exposures along railroad and old Erie Canal.
Precambrian garnet-biotite-gneiss brought to surface along old canal and railroad in upthrown (western) block of Noses Fault. These exposures of the basement could be due to relief of the Precambrian surface or to an anticline being upwarped slightly west ? of the Noses Fault. The basal Paleozoic rock here is the Late Cambrian Little Falls Dolostone. This Precambrian outcrop (one of five within this inlier) is capped by a one foot shaly zone rich in quartz and pyrite; some traces of gold and silver were reported by Darton (1895). Is the shaly zone fault gouge or is it residual soil atop the Precambrian? One must look to the basal Little Falls breccia to determine whether it is tectonic or sedimentary. You be the Judge! Much of the Little Falls Dolostone here is heavily chertified; quartz crystals may be found after careful search. Elsewhere within the inlier, the basal Little Falls is not brecciated but is a dolostone rich in rounded quartz grains. At the Precambrian exposure north of the river along NY 5, a six foot wide mafic dike (unmetamorphosed) cuts the older garnet-biotite-gneiss. The basal Little Falls is concealed but exposures 20 feet above the Precambrian are not penetrated by the dike. Presumably, the dike was injected during a late Precambrian (Keewanawan) orogenic episode. Very scarce lingulid brachiopods are the sole fossils discovered in place in the lower Little Falls at the Noses Inlier. A loose  Elvinia free cheek was found by me along the raIlroad in 1949. Within the Late Cambrian this would signify an early Franconian age.

Noses Fault and Yatesville Creek
Proceed south (uphill) paralleling Noses Fault. Note that Yatesville Creek's course is largely controlled by the fault.

Dragged Shale
Dragged Canajoharie Shale along road on right. Dips up to 75° E.

Ledge of Wolf Hollow Limestone
Ledge of Wolf Hollow Limestone crosses to the east of the road. Canajoharie Shale in road ditch near house. Upper Tribes Hill (Fonda), Chuctanunda Creek Dolostone and Lowville, Amsterdam, Larrabee, and "Shoreham" Limestones are missing here owing to either non-deposition or, more probably, erosion. The Canajoharie Shale, too, is but 350' thick. This area atop the Noses is considered to be the crest of the Adirondack Axis and was an effective barrier to sedimentation and faunal interchange during the Wilderness and early Barneveld Stages of the Mohawkian Series.

Look back at scarp
Looking backward, note Noses scarp extending north toward Precambrian Adirondack Mountains. Land to the east (downthrown block) underlain by Middle Ordovician Schenectady Formation. Throw of the Noses Fault here about 500'.

Largest Horst
For the next two miles we are traveling across the top of the largest horst in the Mohawk Valley.

View to Southwest
Note hills to the southwest near Cherry Valley composed of Lower and Middle Devonian strata. At Sharon Springs, 8 miles south of Canajoharie, Late Silurian Brayman Shales are in contact with Medial Ordovician Schenectady shales. A few miles west of Cherry Valley, the Medial Silurian Clinton Group intervenes between the Late Ordovician Frankfort Shale and the Late Silurian Vernon Shale. The Paleozoic section, thus, thickens markedly as one proceeds west from the Adirondack Axis. The section also thickens markedly east of the Axis but the thickening occurs within the Medial Ordovician.

Dropping off horst
Dropping off western side of the Noses horst; good view looking up the Mohawk Valley toward Fort Plain and St. Johnsville.

River alluvium
Cross Flat Creek and drive on river alluvium to Canajoharie.

Inactive quarry at eastern limit of Canajoharie on south side of NY 5-S exposes the Cambrian-Ordovician contact, i.e. Little Falls Dolostone-Tribes Hill Formation. The uppermost Little Falls Dolostone is stained red with interstitial hematite and has vugs of quartz and anthraxolite. Anthraxolite is a black mineral with 92-98% carbon with much the same composition as anthracite coal. The physical properties, however, are quite different. For example, anthraxolite does not ignite. Note that anthraxolite occupies the lower half of the vugs; the upper half is usually filled with quartz but sometimes dolomite crystals complete the cavity. Anthraxolite is believed to be a hydrocarbon residue of petroleum and to have been derived from algal reefs in the Late Cambrian seas.
The overlying Fort Johnson member of the Tribes Hill Formation is a calcitic dolostone to dolomitic calcilutite. Its scarce fossils (Ophileta, Finkelnburgia, Asaphellus) denote an early Canadian age. Because the uppermost Little Falls Dolostone here has not yielded any fossils (except the non-diagnostic  Cryptozoon we cannot be certain whether the Little Falls - Tribes Hill contact here is a paraconformity (surface of erosion but with no relief) indicating a gap ip the record or whether the subtle change from relatively pure dolomite below to dolomitic limestone above indicates continuous sedimentation from the Cambrian into the Ordovician Period. The physical clues (zone of hematite, vuggy dolomite with contained minerals) lean toward the paraconformity view (see Figure 7). The splendid long stratigraphic sections along Flat and Canajoharie Creeks cannot be examined by large groups. They are, however, critical in reconstructing the geologic history of the Valley and are accordingly included in Figure 3.

Water Gap
Valley narrows to water gap at the "Noses"; valley walls are entirely Little Falls Dolostone.

Dike
Across river, road cut in Precambrian on NY 5 showing six-foot dike cutting garnet-biotite-gneiss.

Anticlinal Effect
Precambrian gneiss and Little Falls Dolostone on right along old Erie Canal and West Shore branch of N.Y. Central Railroad displaying anticlinal effect.

Two Kames
Across river, two kames (chocolate-drop-shaped hills) of gravel and sand in shadow of Noses escarpment. Fonda flat-topped wash plain extends from here for 3.5 miles eastward to Fonda.

Gravel over boulder till
Water-laid gravel and sand overlying boulder till blankets much of the inner valley from here eastward.

Roadcut
Road cut along eastbound lane exposing uppermost Tribes Hill Formation, Amsterdam, Larrabee, and "Shoreham" Limestones.

Auriesville Shrine
Auriesville Shrine atop hill to the south.

Schoharie Creek
Schoharie Creek, east side of Schoharie Valley here is boulder till.

Gailor Dolostone
Across river, large cut in Gailor Dolostone, the dolomitic facies of the Tribes Hill Formation.

Hoffman's Fault
Crossing Hoffmans Fault.

Lower Ordovician Dolostone
Road cuts along eastbound lane in Lower Ordovician Dolostone.

Schenectady Graywackes and Shales
Hills forming Valley walls composed of Schenectady Graywackes and Shales.

Lake Albany Plain
Mohawk Valley broadens into Lake Albany Plain. Note gravels along north river bank. These thick gravels and sands are excellent reservoirs for ground water; the entire city of Schenectady and neighboring suburbs obtain their public water supplies from these almost inexhaustible water-bearing glacial deposits.

Climb out of Mohawk Valley
Climb over south valley wall out of Mohawk Valley proper.

Helderberg Escarpment
Prominent topographic feature straight ahead is the Helderberg Escarpment (not produced by faulting). Note terraces of Lower and Middle Devonian Limestones.

West shore of Lake Albany
Approximate west shore of glacial Lake Albany. Sand plains with profuse growth of pine trees extend from here to Albany. Area of sand dunes atop lacustrine varved clays, the dunes produced by wind whipping the relatively thin veneer of lacustrine sands into north-south trending hills.

Sand Dune
Sand dune.

Boulder till

B: GEOLOGIC EXCURSION FROM ALBANY TO THE GLEN VIA LAKE GEORGE
by Yngvar W. Isachsen

B: GEOLOGIC EXCURSION FROM ALBANY TO THE GLEN VIA LAKE GEORGE

Glacial Lake Albany terrace
The road cuts through an arrested sand dune developed on a former sand terrace of glacial lake Albany.
The excursion route between Albany and the Lake George region passes over the floor of this glacial lake. It is marked by lacustrine sand terraces which have, in part, been reworked by wind to form an undulating dune topography. The landscape has been further modified by post-glacial drainage. Beneath the sand veneer, which is generally less than 50 feet thick, is a rock terrace at about 300 feet elevation. This Tertiary erosion surface forms a broad platform extending between the block-faulted scarp of the Adirondack Highlands on the northwest, and the Taconic Mountains on the east and the Appalachian Uplands to the south.

Descend to Mohawk
Road descends toward the Mohawk River cutting through the blanket of lacustrine sands and into the Middle Ordovician Normanskill Formation which is exposed on the right. Lithologies represented are graywacke with mud pellets ("flysch and chips") and overlying shale. The large area of Normanskill of which this is a part has been interpreted alternatively as a thrust outlier of the Taconic klippe and as the core of a north-trending anticline.

Bridges
The attractive pair of tied arch bridges spanning the Mohawk River ahead received honorable mention for design in 1958 by the American Institute of Steel Construction.

Mohawk and Gorges
Cross the Mohawk River which here occupies a post-glacial gorge cut into the Normanskill Formation.
Immediately to the west is a deeply buried pre-glacial gorge referred to as the Colonie channel (Fig. 6). Since this paleostream channel has the flattest gradient of the tributaries as presently known, it may have been the major river draining the southeastern Adirondack region in Tertiary times. In contrast, the buried Tertiary Hudson channel probably drained the Hoosic and Batten Kill water sheds, as does the present Hudson River, but did not extend much farther north (Simpson, 1949). Beneath the present Hudson River at the foot of Madison Avenue in Albany, the buried Tertiary Hudson channel is almost 100 feet below sea level.
Immediately west of our present location, the floor of this filled channel is about 200 feet below the present Mohawk River which meanders across it at right angles. At the north end of Saratoga Lake it is about 45 feet above sea level, and west of the City of Albany about 80 feet below sea level.
The Northway roughly follows the course of this channel for the next 20 miles or more to a point at the north end of Saratoga Lake (Fig. 6). Beyond this, its extension is largely hypothetical, although supported where drawn across the present Hudson River near Glens Falls by an anomalous lack of outcrop in that short stretch. From Albany north for a distance of about 10 miles where the configuration is best known, it is a relatively steep walled channel, perhaps owing to glacial 'scour.'
The main tributary to the Colonie channel, the ancestral Mohawk Channel shown on figure 6., has been traced as far west as the Hoffman Fault where a 100 foot high waterfall may have existed in pre-glacial times (Simpson, 1949). There are about 200 feet of channel-fill in the stretch between Schenectady and Hoffmans, and the present Mohawk River meanders over its surface.'
Within the next mile the road climbs back up on the Pleistocene cover. Immediately to the east, a bedrock ridge protrudes a hundred feet above the level of the Tertiary terrace. Such relatively rare projections were islands in glacial lake Albany, which had a shoreline at about the present 300 feet contour.

Ballston Creek
Northway crosses one of the glacial meltwater channels which is now occupied by Ballston Creek. Looking down the valley to the southeast the Round Lake depression may be seen. This and Saratoga Lake to the north represent unfilled depressions, perhaps kettle lakes, on the glacial debris occupying the pre-glacial Colonie channel (Woodworth, 1905; Cook, 1930 p. 197).

Drummond Creek
Road descends into the valley of Drummond Creek, and for one-half mile cuts into highly fissile black shale of the Snake Hill Formation.

McGregor Fault
The escarpment which has been intermittently visible to the west extends from Saratoga Springs northward for a distance of 25 miles. It is a fault line scarp produced by differential erosion along the McGregor fault which marks the boundary between the Precambrian (here composed mainly of east-west trending metasedimentary rocks) and the Paleozoics. On the basis of measured Paleozoic sections in the Mohawk and south Champlain valleys, it is estimated that the vertical displacement along the McGregor is at least 2200 feet.
It is only possible at present to date the normal faulting of the eastern and southern Adirondacks and the adjoining Mohawk Valley region as post-Frankfort (i.e. post Late Ordovician) inasmuch as these are the youngest rocks known to be involved. All of the faults in the Mohawk Valley region either hinge out before reaching the Silurian at the base of the Helderberg escarpment, or pass beneath it without being recognized. Field relationships do not permit an absolute resolution of this question, but the fault movement is inferred to have occurred during the Taconic disturbance (Kay, 1942, p. 1627).

Precambrian outcrop
Outcrop of Precambrian; the rock here a quartzo-feldspathic gneiss, similar to that exposed at STOP 1.

Large scale recumbent folding and related structures in biotitic paragneiss.

View of Lake George
Note views of Lake George which lies in a graben between two blocks of Precambrian gneiss.

You are standing on Paleozoic rocks at the floor of the Lake George complex graben, completely surrounded by Precambrian rocks. The steeply rising valley walls are fault-line scarps which give the region a spectacular relief such as is generally found only well within the Adirondack perimeter; the local relief here reaches 2000 feet. Combining this value with the 500 foot estimated thickness of the Paleozoics here gives a minimum vertical displacement of at least 2500 feet.
The crystal clear waters for which this lake is noted, result from the fact that only short mountain brooks drain into the lake, and hence the very fine clay fraction common to most drainage systems is virtually absent. Most of the lake is not deeper than 50 feet, although measured depths of up to 190 feet are shown on the hydrographic map published by the Lake George Power Squadron. The many islands in Lake George number 184, and of those 154 are State-owned. Most are composed of bedrock but several are gravel drumlins according to Newland and Vaughan (1942).
Lake George now drains northward into Lake Champlain, with a decent of more than 200 feet (from 319 ft. to 95 ft.). In Tertiary time, however, both lake basins were river valleys separated by a drainage divide. The Lake Champlain valley drained into the St. Lawrence as it does today, but the Lake George basin drained southward through the relatively wide graben valley located just east of French Mountain (Fig. 7). This valley is now clogged with glacial debris including a well-shaped drumlin 1 and 1/2 miles long (Fig. 7). The inferred Tertiary drainage course is shown in Figure 6.
At the close of the last ice advance, a glacial lake occupied the basin as indicated by the presence of sand terraces representing several transitory levels in the lowering of the lake to its present elevation. The highest of the terraces has an elevation of 600 feet, and is well represented 1 and 1/2 miles to the southeast, just uphill from the Northway exit on Route 9L (see mileage 56.3).
The Paleozoics here are exposed in the railroad bed of an abandoned spur of the Delaware and Hudson Railroad, which carried vacationers from down-state to Lake George via Fort Edward and Glens Falls, until 1957. The exposed dolomite strata are either Little Falls or Beekmantown equivalents; fossils have not been found. A fault breccia in the cut contains fragments of lithographic limestone which are probably down-dragged Beekmantown limestone.
A brief summary of Colonial history of the Lake George region is given in the appendix.

Spheroidally weathered gabbro
Spheroidally weathered metagabbro is exposed in road cuts on the right.

Be alert for falling rock!
This outcrop is interpreted as an untransported soil (saprolith) formed by weathering during the Tertiary from biotitic quartz-feldspar gneiss. Note the degree which Precambrian structures, textures, and minerals are preserved. Above the Tertiary saprolith, the Pleistocene is represented by two fluvioglacial boulder gravel units. The lower gravel is weathered and hence of probable preclassical Wisconsin age; the upper gravel is unweathered and of presumed classical Wisconsin age.
When the exposure was first created in 1936, a 2 to 3 foot thick layer of varved clay was visible between the boulder gravels. This clay is thought to have-accumulated in a local body of water along the ice edge rather than as part of the main glacial lake that occupied the Lake George valley, inasmuch as the clay here is some 180 feet above the highest glacial sand terrace in Lake George Basin (Newland & Vaughan, 1942).
Tertiary saproliths such as this rarely survive Pleistocene glaciation, and are even more rarely exposed, owing to rapid mechanical disintegration and concomitant plant overgrowth. This steep outcrop apparently survives only due to constant removal of material for human use from its base. Similar saproliths have, however, been discovered in a number of localities in the Adirondacks, and in the Hudson Highlands as well, by geologists of the State Department of Public Works in connection with highway construction; they are generally short lived exposures. The structural and topographic conditions that control the preservation of these soils have not been investigated.

Spheroidally weathered gabbro
Where hill starts to level off, note the spheroidally weathered metagabbro cropping out on the right. A fresh outcrop of this lithology will be seen at STOP 5, just north of Warrensburg.

New road cuts being made for the Northway here expose pink, gray and green varieties of granitic gneiss. The typical pink granitic gneisses of the Adirondacks are composed chiefly of microcline or microperthite and quartz along with subordinate amounts of oligoclase and one or more of the dark minerals, hornblende, biotite, pyroxene. In most areas, these gneisses are equigranular, but in parts of the southeastern and northwestern Adirondacks they are inequigranular, containing pink microcline crystals (probably porphyroblasts) which measure up to an inch or more in length. This variety is generally considered to have formed by metasomatism of a biotite-quartz-plagioclase paragneiss into which it grades laterally. A subordinate lithology in this suite is leucogranitic (alaskitic) gneiss which is most prominent in the Northwest Lowlands, although it appears in the southern and southeastern Adirondacks. In the eastern Adirondacks, several large magnetite ore bodies occur in this gneiss. The granitic gneisses occur as sheets or lenses in a variety of other rock types.

Schroon River
The highway follows the flood plain of the meandering Schroon River. Sand terraces at an elevation of about 760 feet may be seen 80 feet above the valley floor. These are representative of Glacial Lake Warrensburg. (Miller, 1923).

Both contacts of this thick sill are clearly delimited, and the lower one is actually exposed.
Aside from obvious metasedimentaries, metagabbro is the only metamorphic rock in the Adirondacks whose origin has never been questioned for reasons given earlier.
Although all the minerals of this sill are the product of metamorphic recrystallization, the textures are relict igneous except at the very margin where the rock has been converted to a biotite schist.
The textures are best shown on weathered surfaces. Throughout most of its width, the sill displays a subophitic fabric, but within a few feet of the contact, the rock has a finer-grained chill border with a diabasic texture. The laths of plagioclase that define these relict textures are not single crystals of plagioclase, as originally, but granoblastic aggregates of andesine-labradorite which presumably represents an equilibrium composition for this metamorphic grade and for this bulk chemical composition. In some Adirondack metagabbros, cores of unrecrystallized igneous minerals have survived metamorphism; most notable are "dusty" plagioclase, augite, hypersthene, and olivine.
Primary constituents of the Adirondack metagabbros are plagioclase (labradorite to bytownite), augite, hypersthene, olivine, ilmenite, and magnetite. Re-equilibration of this mineral assemblage under conditions of granulite facies metamorphism has resulted primarily in reaction between plagioclase and the mafic minerals to produce less calcic plagioclase plus garnet and/or augite. Where water has entered the system, hornblende is a common metamorphic mineral. In many metagabbros the border zone has been converted to amphibolite lacking all trace of the parent igneous texture. Aside from the local addition of small amounts of water, however, the metamorphic reconstitution of gabbroic rocks in the Adirondacks has been an essentially isochemical process. In this exposure, the relatively high biotite content of the metagabbro along its lower contact indicates limited influx of K2O as well as H20 .
This roadcut clearly shows the metagabbro to be a sill. Commonly, however, the poor outcropping characteristics of the thinner metagabbros make it difficult or impossible to determine shape of the intrusives. This may account in part for the fact that the bodies are commonly shown on the older reconnaissance quadrangle maps as circular masses (Fig. 2).

Fault breccia in chloritic hornblende-biotite granitic gneiss is evidence of an episode of brittle deformation. Rotated angular and tectonically-rounded fragments of the gneiss are cemented by a chlorite paste, and within the gneiss biotite is largely altered to chlorite. This retrograde metamorphism and the local presence of drusy cavities are among the features of Phanerozoic faults that transect the Precambrian.
Dating the normal faulting that is so prevalent in the southern and eastern Adirondacks and in the adjacent Mohawk Valley (Fig. 6) is a major regional problem. The wise adage of mining geologists, "Once a fault always a fault," doubtless applies here and further complicates the problem. Inasmuch as the trends, steep dips, and other structural characteristics of those faults which are wholly confined to Precambrian crystallines do not differ from those which also involve the peripheral Paleozoics, it might be assumed that all are of the same age, namely, post-Frankfort, as mentioned under Mileage 31.5. Some faults, however, are marked by healed breccias whose mineral assemblages are in equilibrium with the regional metamorphic grade of the Precambrian Grenville orogeny. Thus, some Phanerozoic normal faulting apparently represents reactivation along Precambrian zones of weakness.
It may be of interest to note in passing that such normal faulting accounts for the rectangular drainage pattern in the Elizabethtown quadrangle to the north. Prior to detailed geologic mapping by Matt Walton, the Elizabethtown quadrangle had been cited for many years as a classic area of rectangular drainage induced by rectangular jointing.

Outcrops of paragneiss
On the left are outcrops of paragneiss, and immediately to the north are exposures of intricately contorted and refolded calcite marble and interlayered calcsilicate rock.

Marble
Road cuts through isoclinally folded beds of calcite marble containing laminae of calc-silicate minerals.

At junction of Route 28 and Potter Brook Road. Charnockitic gneiss. This rock is part of a "charnockitic suite" of metamorphic rocks which has widespread occurrence in the Adirondacks (Fig. 2). The suite includes the true charnockites (hypersthene-bearing gneisses of granitic composition) and varieties departing from granitic composition by: 1) having a lower quartz content than the required 10% (or 20%, depending upon rock classification used), and 2) a range in the ratio of plagioclase to K-feldspar of from less than 1 to more than 1. The gneisses are characteristically gray to dark green in fresh exposures, and weather to a maple-sugar brown; pink facies occur also, however. Microperthite is the predominant mineral; mafic minerals may include hypersthene, augite, hornblende, biotite, and garnet. Owing to the variation in percentages of the "essential" minerals, (commonly within a single mapping unit) and the attempt to fit these lithologies into igneous-rock pigeonholes, they have been mapped under at least 12 different names during the past 50 years. They have been most commonly designated "quartz syenite" and "syenite". However, such terms carry a misleading connotation inasmuch as the rocks are at present largely, if not wholly, metamorphic, whatever their ultimate origins.
In much of the Adirondacks, rocks of this suite occur as unbanded, relatively monolithic layers many hundreds of feet thick. In the southern Adirondacks however, banded charnockitic gneiss with intimately interlayered sedimentary rocks occurs in a number of areas. The monolithic layers are most commonly exposed as the cores of domes and antiforms, as is expectable from their relatively high resistance to erosion.
The Hudson River, which flows by a few hundred feet to the west, is cut into metasediments.

Quarry on right side of the road in banded, pink and gray paragneisses with scattered biotite schist layers. Breccias occur at northern end of outcrop, but more prominent there is a diabase sill with fine-grained chill borders. This is one of many such undeformed diabase intrusives in the Adirondacks. They generally occur as this, steeply-dipping dikes. Inasmuch as they are undeformed they must postdate the Grenville Orogeny. They have been generally interpreted as Late Precambrian.

Roadcut in marble across from junction with road to Friends Lake.
The calcite marble and calc-silicate beds here are typically highly deformed, having been isoclinally folded - and probably refolded as well. The relatively competent calc-silicate layers have been stretched, attenuated, and dismembered well beyond the boudinage stage so that they occur as disconnected lenses, hooks, and clots. Such floating fragments have sometimes been picturesquely tagged "tectonic fish", and "dead snakes". Minerals which can be readily found and identified include graphite, diopside, brown tourmaline (dravite), pyrite, sphene. Undeformed mafic dikes with fine grained chill borders may be seen cutting the marble.
Continue on Route 28 across Hudson River, which here cuts into metasedimentaries.

Cross a second bridge, over small, tributary to the Hudson River, and immediately park on the left at entrance to closed road. Descend to stream, where may be found glacial boulders of most of the resistant Adirondack lithologies. The only major rock type not yet seen on this excursion - anorthosite - is well represented. Both the relatively pure Marcy-type anorthosite, and the more mafic Whiteface type maybe found. Proceeding upstream a short distance, a wide variety of metasedimentary lithologies may be seen cropping out in the stream bed. These include: paragneisses, quartzites of varying purity, amphibolite, marble and calcsilicate rocks.

C: GLACIAL LAKE SEQUENCES IN THE EASTERN MOHAWK-NORTHERN HUDSON REGION
by Robert G. LaFleur
Rensselaer Polytechnic Institute
18 Stops
No road log

Long, narrow drumlins with east-west trend, 2 miles west of Mariaville Lake.

Flaggy boulders of Schenectady Formation predominate drift north of Duanesburg; well exposed along Duanesburg Churches Rd. Excellent view of drumlin terrane north from Highland Park Rd.

Overlook of Duanesburg channel (of Delanson River) at Duane, Rt. 7 one mile south of Duanesburg.

Drumlins north of Rt. 20, 1 1/2 miles east of Duanesburg. Roadcut exposes till. Good view north across Normans Kill valley.

Overlook of lower Mohawk Valley from hill one mile northwest of Rotterdam; 350' terrace remnant of Mohawk delta; river gravels; islands in the Mohawk River at Scotia.

Outlet channel of Early Lake Amsterdam now occupied by NYS Thruway; 1/2 miles west of exposure no .·5.

Delta in Late Lake Amsterdam at Hoffmans; Wolf Hollow gorge of Chaughtanoonda Creek has formed along the Hoffmans Fault, accentuating a striking topographic lineament traceable for 3 miles to the north.

Glenville kames along the West Glenville Rd.; suggesting the location of the ice margin which defended Early Lake Amsterdam.

View from Potter Rd., one mile north of Glenville, south to rock benches of the Glenville Hills.

View from Ostrander Rd., one mile east of Guilderland Ctr., southwest to Helderberg escarpments.

Along Grant Hill Rd., one mile southeast of exposure no. 10; dissection of the south (lee) side of a drumlin by the Normans Kill exposes 100 feet of bouldery till.

Guilderland kame terrace along southwest shore of the Watervliet Reservoir. Several gravel pits expose southwest-dipping gravels and sands; also isolated pockets of rhythmic clays. A solitary kame is located at the intersection of Routes 158 and 146. The Lake Albany 330' beach has modified the northeast (ice contact) side of the kame terrace.

Rensselaer (Lake Albany) kame delta, east of city limits of Rensselaer. Turbidite sands in delta bottomset beds; graded bedding, sole markings.

Lake Albany beach ridge with gravel pit excavation; one mile north of Defreestville on Bloomingrove Rd.

Teller Hill promontory, one-half mile west of Sherwood Park. Panorama of Hudson Valley, the Hampton Park kame delta, and the Hudson flood plain.

Eskers of the Albia-Burden Lake complex, exposed in several large gravel pits on Route 66 east of Wynantskill.

Panorama from East Line Rd., 3 mlles north of Jonesville. Ballston outlet channel at East Line; Round Lake depression and channel, Malta sand plain. Round Lake channel also shown where it is crossed by the Northway one mile east of exposure no. 17.

Coveville outlet and plunge pool three miles south of Schuylerville on west side of Hudson River.

D: GEOLOGIC PHENOMENA IN THE SCHENECTADY AREA
P.C. Hewitt
Wm. E. McClennan Jr.
Harold Nilsson
Three Stops

STOP 1 The Clifton Park Anticline
Location
The outcrop is located at the top of a hill in the town of Clifton Park on N.Y. Rt. 146, 1.7 miles east of the intersection of Rts. 9 and 146. If approached from the east the outcrop lies 0.5 miles west of the intersection of Rts. 146 and 236.
Description
The Clifton Park anticline is an excellent outcrop for teaching purposes. At the one locality many structural and sedimentological features may be observed. It also is a prime example of the thrust faulting in the eastern part of the lower Mohawk Valley. There are only a few faults of this type in the area and they probably represent only small scale thrusting. Though associated with Taconic thrusting they are not part of the Taconic region itself but are west of the westernmost zone of that much discussed area.
The strata exposed at Clifton Park are assigned to the Normanskill formation and represent primarily the Austin Glen Graywacke member. Some black shales are interbedded with the siltstones and graywackes. The mud pebble conglomerate so common in the Normanskill may also be observed at this outcrop. No fossils have been reported from this exposure but the lithology is typical of this Middle Ordovician unit and fossils found in the near vicinity assure this age assignment. The outcrop extends for about 600 feet on either side of the road. It is apparent from a rapid glance that the strata on the north side of the road do not match those on the south side. To gain the most from this exposure it is best to start your traverse at the west end on either side of the road and to walk toward the east and return in the opposite direction on the other side of the road. A series of thrust faults may be seen on either side of the road.
At the west end of the exposure on the south side of the road is a small thrust which may be observed to blend into a bedding plane fault to the east. Virtually all of the faults show mineralization along the fault plane. The mineralization usually consists of well slickensided calcite. No individual fault can be traced any great distance but there is no difficulty in detecting the faults nor in following them over a distance of several yards or more. The entire section of strata on the south side appear to be less contorted than on the north. This is more apparent than real, however, for the whole area is part of an anticline plunging to the south.
Structural features on the north side of the road are quite different. Starting at the east end one may see beds dipping about 30° to the southeast followed by a small symmetrical anticline. About 25 ft. further west is a small faulted anticline. The fault here is a small thrust with a strong drag zone. Gouge may be seen in the fault plane itself. Another small but tight fold succeeds the fault to the west. About 75 ft. from the small fault is an interesting overturned anticline with an east limb dipping only a few degrees to the east and a west 11mb dipping 75° to 80° to the east. As a result the beds on the west limb are up-side-down. For a distance of about 30 ft. is a zone of shattered siltstone which may represent one of the faults on the opposite side of the road. Still walking westward the last structure to be encountered is a symmetrical anticline whose limbs dip 30°. Jointing is obvious through the section.
In addition to the structural elements there are many sedimentary features to be seen on both sides of the road. Mud pebble conglomerates, large ripple-marks, graded bedding and other features may be observed throughout. It is also interesting to note the result of unloading of the surface upon the siltstones and graywackes. Here, the beds have fractured and it is possible to see the difference between the beds which are actually several feet thick and the zone in which the beds appear thinner due to unloading. Furthermore, it is obvious that the beds of siltstone and graywacke do not maintain a constant thickness as one traverses the outcrop.
Discussion
The primary cause of interest at the Clifton park anticline lies in the differences in strata and structural appearance on either side of the road. Some students have suggested that a fault, striking east-west is responsible for the disparity. This seems unlikely and is not needed to explain the exposure. On the contrary, an asymmetrical fold plunging to the southwest which was later cut by faulting seems to provide a simple and more adequate explanation. The explanation lies more in the asymmetry of folding followed by erosion than in any other factor. Certainly there is room for interpretation at this outcrop and we will welcome any comments.

STOP 2 Geyser Park and the "Vale of Springs"
Location
This area is a portion of the state-owned Saratoga Springs Reservation located just south of the city of Saratoga Springs, between N. Y. 9 on the east arid N.Y. 50 on the west. Geyser Park is situated in the western half. Entrance to the Park is via.a new road at the southern limits of the reservation which connects with both Route 50 and Route 9. The old entrance and approach to the Park, near the Hall of Springs, has been closed to vehicular traffic making it impossible to approach the. park from the north. Visitors may, however, elect to park in that section of the reservation and walk down the hill into the upper section of the Park.
Features and Lithology
This area has the highest concentration of "springs" and "geysers" of any area in or around Saratoga. Altogether four "springs" and three "geysers" will be in operation upon the completion of a multi-million dollar reconstruction program.
The mineral waters discharged by the "springs" and "geysers" are representative of the Saratoga type mineral water; a highly saline water charged with varying amounts of carbon dioxide gas. Occurrences of this type mineral water is restricted to only one other locality in the United States.
The wells in the Park,some almost 1,000 feet deep, continuously discharge large volumes of water. The water is carried up in the well by the release of gas pressure in much the same manner as a warm and well-shaken bottle of soda ejects its contents when opened.
This water pressure, passed through a small orifice at the top of some wells, produces the so-called "geysers" to be seen in the Park.
The large proportion of salts in the water, particularly carbonates, produces interesting tufa deposits in the form of cones, flows and terraces.
Geyser Brook, a non-carbonated, non-potable stream winds through the Park from the north, cutting a small valley and exposing the Canajoharie shales in several places. Rather poor specimens of some graptolites can be secured at several horizons in the shale.
Tour and Discussion
The first of three "geysers" to be observed is the Polaris "Geyser." All "geysers" are free flowing, but the force with which they leave the casing is regulated by using a small orifice. All of the "geysers" have been drilled and are actually wells which are allowed to run free. We have placed the word "geyser" in quotation marks since a true geyser is associated with hot water driven from the ground by steam pressure. Part of the cone of the Polaris has been created with stones piled around the casing, but a considerable amount of tufa (travertine) has been deposited since their initial operation.
The Park road eventually reaches a large parking lot, snack bar and comfort station. Further exploration will be on foot. Proceed across the bridge and turn right on the path. Just above the bridge is the Hayes Spring (well). The terminology becomes difficult at this point as both the spring and well apply. The impervious cap rock was pierced by a well in 1909. However, the water flows under its own pressure much as in a spring. Arguments could be collected in favor of an artesian well or spring. The reader is invited to choose one or the other. The Hayes is a pleasant water for those who are native to the area and who have acquired a taste for Saratoga type mineral water. It is well carbonated and moderately saline and popular with mineral water enthusiasts. A hole on the upstream side of the Fountain permits people to inhale the excess gas from the well and it is guaranteed to "clear your head." An analysis of the Hayes Well is appended for people with geochemical interests or for those who are just plain curious about what they are drinking. It is only fair to warn the drinker that many of the dissolved salts have had a reputation as "diuretics and cathartics," and they seldom fail to achieve this result when taken in any quantity. The "geyser" a hundred feet or so upstream is appropriately named the Island Spouter "Geyser." Its waters ascend in a graceful flow to heights of thirty feet or more and is a much photographed object. The tufa cone and surrounding terrace is no more than 40 years old but in that time it has acquired a considerable thickness. The terrace is very slippery and the water tastes the same as the Hayes. Since another terrace is more accessible, it is not necessary at this point to get any closer to it than you are.
A much larger and more impressive tufa flow occurs a few hundred yards upstream where the overflow from the Orenda "spring" cascades over the bank and enters the brook below. This action results in a vertical structure approximately thirty feet high and two to five feet thick. This tufa flow is, in a sense, a miniature Yellowstone of the east, with the notable exception that it is almost 93 percent carbonates from cold water rather than siliceous matter (silicates) from hot water. According to Strock, the travertine is built up at the rate of 0.5 gram/liter of water. Literally translated to English units, it works out to be one pound in 240 gallons, or a potential two tons per million gallons.
The terrace is an interesting physical structure but the tufa itself has a few singular features. First of all, it is radioactive. Minute amounts of radon and other radioactive materials dissolved in the water become highly concentrated in the tufa. The tufa also affords an open-air, above ground exhibition of cave type travertine formation. The rapidity with which it forms causes it to be more coarse and granular but the laminations are readily visible. The rapid formation of tufa gives rise to a sort of "instant fossilization" process. Twigs and leaves are quickly coated with the carbonates and become a part of the fossil record. Loose pieces of tufa show excellent imprints and faithfully record the botanical activity near the terrace. With some luck one can occasionally find an insect accumulating a calcareous overcoat.
Some of the shales on either side of the terrace have a few graptolites. These would be Ordovician but identification is difficult because of an absence of detail. The best horizons seem to range from two to five feet above the level of the path. Further upstream the path terminates at a bridge which crosses Geyser Brook as it emerges from a stone culvert which once carried the water beneath the now abandoned roadbed of the Delaware and Hudson Railroad. This is a very interesting area following a heavy rain; a prime spot to study the Venturi effect on the velocity of liquids.
The pipe discharging water into the stream at the southern end of the bridge is actually the water from the Champion spring (well). The well has sufficient pressure to be a "geyser" and was for a long time, and it may again function as such. The water is noticeably sulphurous in taste and smell, the only water in the Park to have this characteristic. Since this is not typical of Saratoga Mineral Water, we can assume that the casing has been perforated by corrosion and ground water is entering from the shales. Considerable quantities of sulfur water are encountered throughout the Canajoharie and Snake Hill shales much to the consternation of suburban Saratogians. At Saratoga Lake the waters become heavily charged with hydrogen sulfide. Luther's White Sulfur Springs, at one time, was a small spa itself but is unfortunately eclipsed by more famous sulfur springs to the west at Richfield and Sharon Springs. All sulfur water seems to be a product of the Ordovician Shales which outcrop in the Mohawk Valley from Utica eastward.
A second Champion "Spring" flows from the bank about 50 feet beyond the bridge. After crossing the bridge, the path climbs up the west bank and enters a road which passes south along the bank, passing the Orenda "Spring" whose overflow is responsible for the tufa terrace previously inspected. An excellent view of the Island Spouter "Geyser" is obtained along the road just before it descends to stream level at the Hayes Well and the parking lot. The Karista "Spring" is located a few hundred yards down stream on the west side of the brook from the bridge. Its mineral composition and gas content are much lower than either the Hayes or the Orenda. However, unless the visitor has a special interest in mineral water, it might be well to terminate the tour at the bridge and return to the parking lot.
The Saratoga Mineral Water Mystery
The manner in which this water was produced has excited the interest of many people and the theories seem to be directly proportional to the number of investigators. A few facts seem to have universal acceptance.
First, the water is in limestones and dolomites covered with the impervious layers of Ordovician shales which extend to the north, east and south. The Little Falls dolomite was given the credit for some time until Fisher and Hanson (1951) established the dolomite as Ordovician and renamed it the Gailor dolomite.
The water appeared at Saratoga because of an extensive fault (MacGregor) which forms a scarp north of Saratoga and then bifurcates as it approaches Saratoga. The eastern branch of the fault breached the shale and allowed the water to escape upward along the fault plane. This is graphically displayed at the north end of Saratoga Springs at High Rock Park. Route 9N traverses the top of the scarp and at the base approximately 30 feet of dolomite is exposed. High Rock Park is the site of the High Rock Spring, a true spring, which was known by the Indians long before Jacques Cartier first reported it in 1535. Only the tufa cone of this spring remains but a hundred yards to the north the Old Red continues to flow, having done so since 1774.
The control of the fault is striking. All springs and wells are always on the eastern side and the water issues forth at many places from Wilton, four miles north of Saratoga to Ballston Spa, seven miles to the south. Altogether some 200 springs and wells have produced Saratoga type mineral water, and always on the eastern side of the fault.
The source of the large mineral and gas content of the water has always been the difficult part of the problem.
Kemp (1912) looked to some deep-seated source for CO, Cl, Br and Fe. His ideas were deeply influenced by the presence of an old volcanic mass at Northumberland (Stark's Knob) some 15 miles northeast of Saratoga.
Strock (1944) on the basis of geochemical data, felt that the chemical content was in many ways related to sea water. As a result he placed the source in the Salina group, the extensive salt beds of Central-Western New York. Such beds extend eastward into Schoharie county, an area about forty miles to the southwest of Saratoga. Ruedemann-Cushing (1914) suggested that Saratoga waters originated to the east of the region, aided in their movements up the bedding planes and fractures of the limestones and dolomites by a hydrostatic head established in the Green and Taconic Mountains. The "volcanic exhalation" would doubtlessly furnish the CO2 but in all probability furnish other gases as well. It leaves a question as to the mineral matter and overlooks the lack of any thermal activity which in most cases might be associated with deep seated activity.
The virtual absence of all sulfates in the Saratoga water is difficult to correlate with the average chemical composition of sea water, either ancient or recent. Strock (1944) envisioned the water as coming down the Mohawk Valley and then moving northward. Unfortunately the dolomite outcrops long before it reaches the fault and in all probability would give up the water long before it reached the Saratoga fault. Then, too, it must be remembered that all wells and springs occur on the eastern side of the fault. The eastern basin theory seems to have fewer "ifs" and more positive evidence. The limestones and dolomites are buried at depth and covered by thick and impervious shales. The upturned edges of these beds, raised in the Taconic disturbance, collects the water. The limestones and shales are reasonably competent and withstood the compression of the Taconic disturbance without difficulty until it grounded out against the crystalline base of the Adirondacks. The north-south lineation of the fault would tend to substantiate this idea. This places the source of the water in the dolomites and limestones. Considerable amounts of sodium, calcium and magnesium salts are available plus the halogens which are noticeably high in the water. The Hoyt limestone beneath the dolomite contains a vast  Cryptozoon population which suggests shallow seas and possibly intermittent periods of dryness whereupon some elements would crystallize out and into the calcareous material of the sea floor. Any acid bearing ground water introduced into these carbonates would immediately begin an attack on the carbonates which in turn would begin the production of CO2. This gas, sealed in the aquifer by the shale above and brought up in pressure by a hydrostatic head, would produce a strong carbonic acid system which would increase with further solution until reasonably high pressures were developed. More than ordinary solution would occur, unlike the conventional solution as observed in other limestone areas. The water, driven westward by a hydrostatic pressure, reaches the fault and is carried up the thousand or more feet by the sudden release of the gas pressure. Colony (1929) in his report to the Saratoga Springs Commission examines all previous ideas and debates them in far more detail. Although the mineral water industry has declined seriously, the controversy as to its source and origin has flourished. Anybody with a new theory??
Selected References
Colony, R. J. 1929 Report to the Saratoga Springs Commission, Restudy of the Geology of the Saratoga Area and the Problem of the Mineral Waters. N.Y.S. Legislative Document #70, 1930.
Fisher, Donald W. and Hanson, George F. 1951 Revisions in the Geology of Saratoga Springs, New York and Vicinity. American Journal of Science, Vol. 249, Nov. 1951, pp. 795-814.
Kemp, James F. 1912 The Mineral Springs of Saratoga. N.Y. State Museum Bull. No. 159, pp. 5-79.
Rudemann, R. and Cushing, H.P. 1914 Geology of Saratoga Springs and Vicinity. New York State Museum Bull. No. 169.
Strock, Lester W. 1944 Geochemical Data on Saratoga Mineral Waters-Applied in Deducing a New Theory of Their Origin. Publications of Saratoga Spa No. 14, 1944.
DEC Links 1 2 3

STOP 3 Stark's Knob
Stark's Knob is a protuberance of volcanic rock located north of the town of Schuylerville, New York. It was named after General John Stark of the Revolutionary Army that hindered Burgoyne's retreat to the north (Woodward, 1901). It is found 1.2 miles north of Schuylerville just west of New York State Highway #4. The Knob is a mass of'basalt about 200 feet high and is surrounded by Ordovician Normanskill shales. The rock has been quarried for road metal resulting in exposure of the interior of the rock mass. In describing the Knob and locating its features, it will be convenient to refer to the quarried face on the east and the natural face, which is a steep cliff, on the west. Prior to quarrying, the Knob was probably ovoidal or circular. It may be noted that basalt is also found on the south side of the dirt road located south of the Knob.
Standing at the base of the quarried face one can see a mass of dark basalt broken by many fractures and fault planes. A prominent fault or fracture extends upward along the middle of the quarried face. A less obvious fault exists about 50 feet up slope from a small circular well or pool at the base, near the southern corner of the quarried face. One can also see pillow lava or lava ball structure displayed allover the quarried face. The western natural face is almost vertical on its north end and is partially covered by talus on its southern end. The southern portion of the Knob is unquarried and is extensively covered by brush and trees. A foot path extends over the crest of the Knob. At the summit" a plaque offers the history of the area and a presumed explanation of the geology.
Rock Types
The basaltic Knob is surrounded by slaty shales of the Normanskill formation. The shales are blue-gray and weather to buff and locally rusty-red. Cleavage is well displayed, and bedding is obscure. The shale-basalt contact is exposed on a small hump at the base of the Knob along the dirt road leading to the quarry. The contact is also exposed along the northern end of the Knob at the edge of the quarry where it curves eastward, and in a small patch near the summit along a path leading down the talus slope of the natural face. No apparent macroscopic contact metamorphism of the shales has been observed. Some of the shales at these contacts may be fault slices or inclusions in the basalt.
Where the shales have been faulted, their character changes. This may be seen at the base of the quarry area and on a linear mound or hump which trends east-west at the base of the Knob on its southeasterly side (south of the quarry area). This mound will be discussed in the section on structure. The shales, which apparently have been faulted, do not show such prominent fissility as displayed in shales farther from the Knob. The rock has curved, platy surfaces and weathers rusty-red.
The basalt occurs as pillows) balls or ovoidal structures embedded in a matrix. Both the lava balls and the matrix are liberally penetrated by calcite veins. The pillows range from approximately an inch to four feet along the greatest dimension. They display radial jointing in the outer portions. The lava pillows are surrounded by a dark~ foliated~ shaly matrix. This matrix concentrically surrounds and winds through the space between the pillows. Some pillows have a dark, glassy coating which in some places appears to be part of the matrix and at others, part of the pillow. Lava balls and limestone inclusions are beautifully displayed on the quarry face. Balls of varied sizes and shapes are randomly grouped. The balls show coarser grained interiors with a fine grained rind on the surface. In'rare cases they display characteristic pillow structure including the tail-like feature.
On the southeast unquarried portion of the knob the basalt does not show ball-structure as clearly. This rock is very porous, apparently due to leaching of calcite or some other mineral. There are many large and small holes in which lady bugs may be found hibernating during cold weather. This porous rock crumbles when struck by a hammer. Massive patches of basalt in which faulting is manifested by planes with slickensided calcite also occur on the unquarried portion of the knob. On both the quarried and natural faces the lava pillows contain amygdules. Many pillows, however, show no amygdaloidal structure.
Limestone inclusions may be found readily in the lava balls. The limestone is medium to dark gray and is medium to fine grained. The limestone weathers to buff or tan~ surrounded by a darker portion near contact with the basalt. Fracturing along calcite veins may give the appearance of a limestone inclusion. Care must be taken to make sure one is looking at an authentic inclusion. On the natural face the limestone is especially different from the quarried face. Here the inclusive nature of the limestone is less apparent and the limestone may actually be in the matrix. Locally a limestone matrix with basalt fragments appears as a breccia. The limestone itself is porous and is almost entirely calcite. An extremely small amount of fine, unidentified, insoluble residue was obtained from this limestone.
Structural Geology
The only secondary structures that can readily be seen in the basalt are fractures and faults. On the quarry side there are many ledges, over which one may walk, which exhibit slickensided calcite. Locally, calcite veins offset by fractures can be found. Along the crest over the quarry face there are fractures which are parallel or semi-parallel. Calcite veins occupy some of the fractures. Along this same crest and on the natural face the fractures are closer spaced than on the quarry side. Throughout the knob, calcite and quartz crystals occupy large fractures. Irregular calcite veins pervade the basalt and are not apparently related to fractures.
Faulting is manifested in the slickensides found along the calcite veins. At least some faulting must have taken place after the deposition of the calcite. There is one large fault plane or fracture striking N 500W and dipping 520 NE on the quarry side. It is covered with talus and vegetation making investigation difficult. Another prominent fault striking N 450W and dipping 320 NE is exposed above the small well just south of the quarry area. The rock here is crushed, folded and has a peculiar shaly appearance and is probably gouge. There is basalt above the fault and talus below. Intersecting this fault almost perpendicularly is another fault which strikes N 650W and dips 790 NE. The fault surfaces here have very prominent slickensides.
The linear mound or hump mentioned previously strikes N 550E and plunges away from the Knob near the bottom of its southeast slope. The hump is about 12 feet across and 70 feet long. The rock exposed here is slaty shale but, as mentioned before, is different from the surrounding Normanskill shales.
Problems of Stark's Knob
This report is, of course, brief, superficial and almost entirely descriptive. It does not propose nor support any genetic theories for Stark's Knob. However, one cannot help but question the origin of this rock, and how it, unlike any other in the State, could have occurred here.
The main question concerning the origin of Stark's Knob is whether it is a volcanic neck, indigenous to this locality, or an allochthonous mass faulted in from some other area.
Cushing and Rudemann (1914) hesitantly support the theory that the knob is autochthonous and was intruded where it stands. Never the less, they acknowledge the apparent lack of contact metamorphism and the absence of any inclusions, especially shale, other than the limestone.
The irregular, fine grained calcite veins contrasted to the coarse, crystalline and slickensided ones may indicate more than one period of calcite precipitation. The pillow-type structure is similar to known subaqueous pillow lavas, hinting at under-sea extrusion of the basalt precipitating calcium carbonate dissolved in the water.
Bibliography
Cushing, H.P., and Ruedemann, R. 1914, N. Y. State Museum Bull. 169, p. 115-135
Woodward, J. B., 1901, N. Y. State Geol. 21st Rept., p. 17-24.
DEC Links 1

GEOLOGY OF WESTERN NEW YORK
Guidebook
New York State Geological Assn
1964
Department of Geological Sciences
State University of New York at Buffalo
Buffalo, N.Y.
E. J. Buehler, Editor

A: SILURIAN STRATIGRAPHY OF WESTERN N.Y.
by Edward J. Buehler
State University of New York at Buffalo
and
Wiliam J. Kilgour
Buffalo Museum of Natural Sciences

A: SILURIAN STRATIGRAPHY OF WESTERN N.Y.

STOP 1. DeCew Generating Station
Refer to papers by Fisher (p. 1), Kilgour (p. 10), and Zenger (p. 19). The following stratigraphic column for DeCew Falls is taken from Bolton, 1949.
0 - 12 | Dolomite, light grey dense nodular, weathering buff to white. | Lockport
12 - 25 | Dolomite, as above, but with abundant nodules of chert. | Ancaster
25 - 56 | Limestone, coarsely crystalline and porous, or sandy, with thin shale interbeds. | Gasport
56 - 64 | Dolomite argillaceous to sandy, calcareous, dark grey, weathering buff to tan. | DeCew
64 - 120 | Shale, fissile, green-grey to dark grey. | Rochester
120 - 127.5 | Limestone, pink to dark grey, coarsely crystalline, crinoidal. | Irondequoit
127.5 - 134 | Limestone, dolomitic, dense, light grey; top 0.5' sandy. | Reynales
134 - 142 | Limestone, dense, light grey, massive, with thin sandy partings. | Reynales
142 - 143 | Shale, greenish grey to dark grey. | Neahga
143 - 148 | Sandstone, fine grained, massive, white to light grey, with a few thin shale partings. | Thorold
148 - 148.5 | Shale, dark grey. | Grimsby
148.5 - 152 | Sandstone, as above | Grimsby
152 - 183 | Sandstone, fine grained, red mottled with green, with interbedded red shale. | Grimsby
183 - 194 | Shale, red and green, with minor beds of red sandstone. | Grimsby
194 - 242 | Shale, dark grey to green, calcareous, with beds of sandy shale and light grey calcareous sandstone. | Power Glen
242 - 254
Sandstone, quartzose, white to light grey, massive to thick bedded with small scale crossbedding. Thin zones of grey shale pebbles (intraformational conglomerate).
Whirlpool
254 - | Shale, brick-red with 0.3' of light green shale at top. | Queenston

STOP 2. Lunch. Examination of exhibits at Power Vista.
Following is the stratigraphic section here. See papers by Fisher (p. 1), Kilgour (p. 10), and Zenger (p. 19), for details.
Eramosa | 20'
Goat Island | 19'
Gasport | 27.5'
DeCew | 8'
Rochester | 68'
Irondequoit | 26'
Reynales | 8'
Neahga | 6'
Thorold | 7'
Grimsby | 52'
Cabot Head, etc. | 36'
Whirlpool | 25'
Queenston | 100' exposed

Ascend Niagara Escarpment

Lockport Dolomite outcrop

STOP 3. Frontier Crushed Stone Quarry
The following units of the Lockport are exposed here. See paper by Zenger (p. 19) for details.
Goat Island | 24.0'
Gasport | 29.5'
DeCew | 8.5'

STOP 4. Akron Falls
STOP 4A. The following members of the Bertie dol. are exposed at the falls. See paper by Rickard (p. 24) for further details.
Scajaquada | 8'
Falkirk (the massive Member) | 20'
Oatka | 20'
The reentrant of the base of the falls is identified as the top of the Camillus Shale.
STOP 4B. About 1/4 mile upstream from the falls. The units here are:
Nedrow member of Onondaga | about 6' exposed
Edgecliff member of Onondaga | 5'
-- Silurian-Devonian unconformity --
Akron dolostone | 8'
Williamsville member of Bertie | 6'
See papers by Rickard (p. 26), and Oliver (p. 32) for details.

B: UPPER DEVONIAN N.Y.S.G.A. FIELD TRIP
by Dr. Irving H. Tesmer
State University College at Buffalo

B: UPPER DEVONIAN N.Y.S.G.A. FIELD TRIP

Onondaga Limestone
Observe Onondaga Limestone to left (Buffalo NW quad)

STOP 1. Hamburg Park
Hamburg Park (Buffalo SE quad); exposures of Ledyard and Wanakah

STOP 2. Home of Piarist Fathers
Home of Piarist Fathers (Eden quad); exposures of Wanakah, Tichenor, Windom, Genundewa and West River;
2010: Now the Graycliff Conservancy maintains this Frank Loyd Wright house

STOP 3. New York Central Railroad Bridge.
Arrive 11:15. Follow path to left along west side of railroad to banks of Eighteen-mile Creek (Eden quad); observe exposures of Cashaqua and Rhinestreet; depart 11:30.

STOP 4. Church Parking lot
Walk 0.2 miles further east along Eighteen-mile Creek Road to U.S. 20 and then to bridge over Eighteen-mile Creek (Eden quad); observe exposure of Rhinestreet; depart 12:00.

Sand Ridge
Observe prominent sand ridge to right (Angola quad) . Next 1.2 miles.

STOP 5. Evangola Parking Lot
Arrive 12:30. Evangola State Park (Farnham quad);lunch and rest stop; exposures of Angola Shale; depart 1:30.

STOP 6. Bridge over Cattaraugus Creek
Arrive 11:45. Niagara Trading Post and bridge over Cattaraugus Creek (Farnham quad); observe Angola Shale and preglacial course of Allegheny River; depart 2:00.

STOP 7. Walnut Creek
Arrive 2:15. Walnut Creek (Silver Creek quad); exposures of Angola, Pipe Creek and Hanover; depart 2:45.

STOP 8. Point Gratiot Park
Arrive 3:15. Exposures of Dunkirk Shale; depart 3:30.

Hanover Shale
Observe various exposures of Hanover Shale in the Lake Erie cliffs to right (Silver Creek and North of Dunkirk quads). (Next 4.7 miles.)

Abandoned Lake Beach
Observe abandoned lake beach to right, associated with glacial Lake Warren at Sheridan, New York (Dunkirk and Forestville quads)

Hanover-Dunkirk contact
Silver Creek interchange #58; observe Hanover-Dunkirk contact (Farnham quad).

Rhinestreet Shale
Observe exposures of Rhinestreet Shale (Buffalo SE quad). (Next 0.3 miles)

C: LATE PLEISTOCENE GEOLOGY AND GEOMORPHOLOGY OF NORTHWESTERN NEW YORK
by Parker E Calkin and Charles J. Caseau
State University of New York at Buffalo

C: LATE PLEISTOCENE GEOLOGY AND GEOMORPHOLOGY OF NORTHWESTERN NEW YORK

Subdued Niagara Falls Moraine
Pass south over very subdued Niagara Falls Moraine; 20-30 feet of relief at stream cuts on otherwise very flat plain of Lake Tonawanda. This is the lowland of Upper Silurian, Salina Group.

Plains of former Lake Tonawanda
Turn right at Exit N-16 onto U.S. Rt. 290, Youngman Expressway, and proceed east over plains of former Lake Tonawanda.

Onondaga limestone Escarpment
Rise south over Onondaga limestone (M. Dev.) Escarpment. Exposure here in roadcut as you pass under Main Street.

Cazenovia Creek
Cazenovia Creek, a tributary of the Buffalo River at your right.

Morainal ridge
Turn left (E) onto Main St. and proceed along well defined morainal ridge at 660-670' through Ebenezer. Ridge is a probable westward extension of Leverett's (1902) Alden Moraine. DeCew 15' Orchard Park 7 1/2' It has been mistaken for a Lake Dana beach ridge but has probably been altered by Lake Dana waters (680-700'). Cellar cuts reveal a dense till, rich in large, striated boulders of Onondaga limestone.

Subdued morainal ridge
Join Seneca St. and proceed along subdued morainal ridge.

Road collapse
Turn right (SE) onto N.Y. Rt. 16, still continuing on Seneca Rd. At right, lateral migration of Cazenovia Creek has caused collapse of paved road.

Tichenor limestone falls
Note at left the falls formed by resistant and fossiliferous Tichenor limestone Member.

Glacial Lake Warren beaches
Beyond intersection with Kingsley Rd., Northrup crosses shaley gravel of glacial Lake Warren beaches, 800-830'. At left, 7 miles beyond is gravel beach ridge, 830', behind green house.

Glacial Lake Whittlesey
Proceed left (S) on Transit Rd. rising up to glacial Lake Whittlesey features, 900'.

STOP 1. Cancer Prevention Research Center.
View postulated, (Fairchild, 1906) Lake Whittlesey, wave-cut beach and scarp at left and right on north side of hill. Ridge appears to be largely shale, but its north side is partly flanked by well sorted sand.

Ridge crest in Lake Whittlesey gravel
Cross ridge crest (880') after .3 miles. Cellar of Barren house at right, was dug in Lake Whittlesey (?) gravel. Bear right (S) beyond ridge onto Willardshire Rd.

Hamburg Moraine
Proceed past probable kame moraine gravel ridge at right on north side, Hamburg Moraine.

Hummocky terrain
Cross Cazenovia Creek and proceed on Willardshire Rd. across typical hummocky topography of Hamburg Moraine.

Lake Whittlesey beach
Proceed through intersection of Jamison and Conley Roads with Seneca Rd. which overlie a Lake Whittlesey beach and spit at 900'. Beach topography is now nearly obscured except for minor sand ridges on grounds of Moog Plant at right (N). Descend from split, .3 miles west of Moog Plant.

Beaches of glacial lake Warren
Turn right (E) beyond Church onto Rice Rd. which follows beaches of glacial lake Warren (lower or second Lake Warren).

Beach Ridge
Observe prominent beach ridge at left of intersection with Dellwood Dr.

Pit cut in beach
An abandoned gravel pit 1.3 miles beyond Seneca Rd. cut in the beach exposes 20' of well sorted gravel.

Second Lake Warren ridges
Note again at least two prominent ridges of Second Lake Warren (Blackmon, 1956) left, .7 miles from Bowen Rd.

Cross Buffalo Creek.
Pipeline trenches adjacent to creek here revealed 2' of gravel over blue shaley till.

Lake Warren beach ridges
Turn left onto Stille Rd. (Stolle Rd.) noting well formed beach ridge of Lake Warren on right. Cross at least 3 NE-SW trending ridges of Second Lake Warren 835-800'.

Delta
Turn right onto Clinton Rd. and pass across delta of Buffalo and Little Buffalo Creeks formed in Lakes Whittlesey and/or Warren.

STOP 2. Huber and Huber sand pit.
Turn right into Huber and Huber sand pit. Observation and discussion of exposed Lake Warren beach and delta structures.

Beaches
Turn left (N) onto Town line Rd. and pass across beaches of Second Lake Warren, possible Lake Wayne 800' (.4 miles), and Lake Grossmere, 790;, (0.8 miles) beyond Clinton Rd.

Possible Lake Wayne beach
Possible Lake Wayne beach 800' (.4 miles from Clinton).

Possible Lake Grossmere beach
Possible Lake Grossmere beach 790;, (0.8 miles) beyond Clinton Rd.

Cayuga Creek
Cross unidentified beach ridge, 760', and Cayuga Creek, the eastern most river draining into Erie Basin. Proceed south over very subdued remnants of Alden Moraine. Borrow pits and cellar cuts reveal red, stony silts and normal clay till in this general region.

Ice contact deposits
Cross Ellicott Creek and turn left (W) onto N.Y. St. 33, Genesee St. Pass gravel pits in ice-contact deposits on right.

STOP 3. Pine Hill Concrete Co. sand and gravel pit.
Over 45' of ice-contact, stratified drift is exposed on the northeast corner. Thin layers of flow (?) till occurs at some horizons and the deposit is overlain by 7-10' of cobbly till in the northwest corner. This together with cross-bedding data suggest a possible (a) kame delta or (b) ice marginal stream origin. These and adjacent deposits may be related to the Buffalo Moraine of Kindle and Taylor (1913) .

Down Onondaga Escarpment
Proceed under Sheridan Dr. overpass and down Onondaga Escarpment to Lake Tonawanda plain, 630'. This area is largely underlain by lacustrine red silts and clays overlying Camillus Shale (U. Silurian). Scattered till ridges and drumlins project above its surface.

Crest of Niagara Falls Moraine
Cross over crest of Niagara Falls Moraine.

Drumlin
Turn right (E) onto Branz Rd. (Bartz Rd.) and proceed up onto NE-SW trending drumlin. This and next drumlin have no more than 35' of relief but stand out clearly from flat Lake Tonawanda plain.

Crest of NE-SW trending drumlin.

Hummocky ridges of Barre Moraine

Barre Moraine crests
Good crests of Barre Moraine, near stop light at Lincoln Ave., City of Lockport.

Barge Canal / Erie Canal
Cross N.Y.S. Barge Canal/Erie Canal at Lockport. Canal leads NE through one of Lake Tonawanda outlet spillways.

STOP 4. Outwater Park for lunch
Turn left onto Outwater Dr. and proceed to Outwater Park for lunch. The park lies on the Lockport Dolostone (M. Sil.) forming the prominent Niagara Escarpment overlooking glacial Lake Iroquois plain to north. Lake Ontario lies 11 miles to the north.

Spillway draining Lake Tonawanda
You are passing down from Niagara Escarpment through one of many spillways cut by water draining from Lake Tonawanda to Lake Iroquois.

Ridge Rd. follows the Lake Iroquois beach ridge
Ridge Rd. follows the Lake Iroquois beach ridge, 390'+; Lake Ontario stands at 246'.

Bar of Lake Iroquois.
Bear right following N.Y. Rt. 93 at fork onto bar of Lake Iroquois.

STOP 5. Abandoned gravel pit
Abandoned gravel pit exposes shingled gravel of Iroquois bar, lightly cemented with secondary calcium carbonate as to preserve details of imbrication, bedding, and cut-fill structure.

Iroquois Beach
Turn right (W) onto RL 104 Ridge Rd. and proceed along Iroquois beach to Lewiston. Note Niagara Escarpment prominently displayed at left is reached at Dickersonville, where rise begins from Iroquois plain, 400' to Tonawanda Plain at 600'+.

Proceed up Niagara Escarpment
Turn left (S) onto N.Y. Rt. 18, Creek Rd. at outskirts of Lewiston and proceed up Niagara Escarpment. After.4 mile note exposure of Lockport Dolostone at left and view to right of Escarpment, and the broad Lower Niagara River. Emerging from the Gorge at Cataract Basin, the river spreads out to a width of 2,000', flowing with a gradient of less than 0.16' per mile to Lake Ontario 6 miles to the north.

Cross Niagara River
Cross Niagara River into Canada with Old Narrow Gorge and power projects at left, Lewiston Branch Gorge Section and Cataract Basin at right.

Brock Monument
Turn right (S) at first exit after paying toll, and after .4 mile turn right again at intersection with Niagara Park Commission, "River" Road. Brock Monument, and Niagara Escarpment are at your left (N). Proceed south over Barre Moraine represented by hummocky relief .5 mile from the bridge toll stop.

Sir Adam Beck Niagara Generating Station No.2
Pass Sir Adam Beck Niagara Generating Station No.2, a facility of Ontario Hydro. From this area to the Whirlpool (Stop 7) we pass through a shallow channel of the Niagara R. from Lake Tonawanda to Lake Iroquois. The deposits are red Silts with grey clay layers overlying bouldery till.

STOP 6. Vista
Vista overlooking Gorge and Robert Moses Niagara Power Plant. Both Canadian and American Power Stations take their water from the Upper Niagara River. A clear view Of the Niagara stratigraphic section is revealed here from Queenston Shale to the Lockport Dolostone at the top. Proceed south along River Rd.

Wintergreen Flats and Niagara Glen
Pass Wintergreen Flats and Niagara Glen at left. Large talus blocks, some 20' in diameter and cut by giant potholes, lie below massive dolostone cliffs which remained when the retreating former Falls narrowed and gorge cutting resumed to the east.

STOP 7. Whirlpool Basin
Turn left off main road to the Whirlpool parking area. The Whirlpool is a basin 1,700' by 1,200' with a maximum depth of 125'. The water enters the Whirlpool at high velocities after moving up to 30' per second through the Whirlpool Rapids upstream. Most of the flow rushes past the outlet to the far side of the Pool, makes a complete circuit counterclockwise, and escapes through the narrow outlet by passing under the incoming stream. Below the Whirlpool, there is another two miles of rapids with a drop of 40'. The feature responsible for the Whirlpool is the buried St. David's Gorge, intersected here by the Niagara Gorge. It is observed trending northwest from the opposite side of the Whirlpool and extends to the village of St. David on the escarpment west of Lewiston. Various excavations for road, canal, and power projects reveal that it has steep sides and a depth approximate to that of parts of the Niagara Gorge. It has been filled by till, mantled with red lacustrine silts and gray clays probably related to the former Lake Tonawanda. The Middle and Lower Silurian section is clearly revealed here. The Whirlpool Sandstone is at the river level,

Cross Bowmen River
Continue south along River Road. Cross Bowmen River which has partially excavated St. David's Gorge.

STOP 8. Refectory view of falls
Refectory view of Upper Great Gorge, American Falls, Goat Island, and Horseshoe (Canadian)Falls at right. Goat Island divides the Upper Niagara River into two channels, one leading to the American' Falls and the other to the Horseshoe Falls. In each channel the water flows over resistant ledges of the southerly dipping Lockport Dolostone Caprock to form rapids and cascades with a drop of about 50'. Before construction of a submerged weir above the Cascades (Horseshoe Rapids), only five per cent of the total flow went over the American Falls; a little more than one half the present percentage. The relatively small flow is distributed evenly along the 1,1OO feet crest of the American Falls so that the discharge per feet rarely exceeds 20 cubic feet per second compared to a maximum of 200 at the Horseshoe. At the 2,500' wide crest of 510-520' above sea level, there is a straight drop of about 160'. The crest has been lengthened as much as 100' in the past 100 years because the central portion recedes faster than the ends. In some places along the crest, there are depths from 6 to 12' but there are several small islands and shoals. In particular, there is a large central shoal dividing the flow into two main channels, which converge toward the central part of the crest. The massive Lockport caprock of the Falls is clearly shown beneath the observer and between the two falls. It is some 80' thick here, thickening to 130' south at the Cascades head. The black Rochester Shales beneath are hidden by the falls and the blocky dolostone talus. The latter is not removed from beneath the American Falls because of the low discharge. The recession of these shales has caused undermining and consequent joint block by joint block retreat of the Falls from Lewiston. The river in the Upper Great Gorge below the Falls, drops only five feet in its two and one quarter mile length. Soundings show maximum depths of from 100' to 187'.

STOP 9. Horseshoe Falls and Scenic Tunnels.
Proceed south, passing the Cascades and Canadian Niagara and Toronto Power Plants successively on the left, and the river-cut cliff and shelf in the Niagara Falls Moraine at right. This latter cut, now occupied by Queen Victoria Park was probably made (Taylor,. 1932) after the Falls had retreated past the high point of land just north of Stop 7. At this time the curved course of the river in the rapids threw a powerful current against the bank west and south of the fall.

Niagara Falls Moraine
Turn right (W) encircling Dufferin Is. and skirting 60' cliff of Niagara Falls Moraine. Return north toward Rainbow Bridge past Falls.

Power Intakes
Pass Niagara River and Power Intakes for Robert Moses Power Project. Twin conduits, each 46' by 66', carry water four miles beneath the city of Niagara Falls, The concrete bulkheads held the closing doors for these conduits.

D: ONONDAGA LIMESTONE IN WESTERN NEW YORK
by Dr. Edward J. Buehler

D: ONONDAGA LIMESTONE IN WESTERN NEW YORK

STOP 1. Buffalo Crushed Stone Quarry
STOP 1. 9:00 A.M. See paper by Oliver (p. 32) for stratigraphic details. Leave Quarry at 10:00 A.M.

STOP 2. Onondaga Bioherm
STOP 2. Arrive at Quarry at 11:15 A.M. This quarry exposes an Onondaga Bioherm. See paper by Oliver (p. 32) for details. Leave quarry at 12:15 P.M.

E: HAMILTON FOSSIL LOCALITIES
by Harvey Hambleton
Buffalo Museum of Natural Sciences

E: HAMILTON FOSSIL LOCALITIES

STOP 1. Oatka Creek shale and Stafford Limestone.

STOP 2. Centerfield Limestone.
This is the most western outcrop of Centerfield.

STOP 3. Wanakah Shale and Ledyard Shale.

STOP 4. Tichenor Limestone and Wanakah Shale.

May 5-7, 1967
GUIDEBOOK FOR FIELD TRIPS
Editor
Russell H. Waines
HAMILTON COLLEGE
Clinton, New York

A: THE PLEISTOCENE GEOLOGY OF THE WALLKILL VALLEY
G.GORDON CONNALLY
S.U.N.Y. College at New Paltz
LESLIE A. SIRKIN
Adelphi University

A: THE PLEISTOCENE GEOLOGY OF THE WALLKILL VALLEY

Schunemunk Mountain
Railroad Underpass. Schunemunk Mountain, a northeasterly plunging syncline is on the left. This is the easternmost manifestation of typical Appalachian, ridge-and-valley topography.

Salisbury Mills and Moodna Creek
The village of Salisbury Mills with Moodna Creek close by on the left. Moodna Creek served as a major drainage-way for pro-glacial lake waters in the Wallkill Valley and controlled the 400 foot lake level reported by Adams (1934).

Home of Brotherhood Wineries
Washingtonville is the home of the Brotherhood Wineries, reputed to be the oldest in the country in continuing existence.

Post-glacial stream channel
Note the post-glacial stream channel cut in bedrock. This channel is the result of a drainage reversal caused by the deposition of a crevasse filling (moraine?) south of Chester. This stream originally flowed southward into Black Meadow Creek but now drains only the muck area north of Chester.

View of Chester Esker
The Chester Esker is on the right side of the road.

Chester Esker
The road ascends the 60 foot high Chester Esker. This esker has its crest at about 540 feet and evidently represents a channel that drained southward through stagnant ice, into the 500 foot lake in the southern Wallkill Valley. This channel was probably in existence during the building of both the Pellets Island and New Hampton Moraines.

STOP A-1 Gravel Pit
This gravel pit is operated by Chester Ready-Mix. It is part of a southward extension of the ice channel filling represented by the Chester Esker. Examine the relationship between ice-contact stratified drift, flow (?) till, and non-ice-contact drift. In addition, examine the exotic lithologies represented in the gravels.

Ice-margin
Turn left (west) on Route 94. The road essentially parallels an ice-marginal position between here and Florida, New York.

Muck farming
Cross Quaker Creek on small bridge. This is the main muck farming area of Orange County. The organic soil is the result of filling of a 500 foot pro-glacial lake with lake silts and then organic deposits. On approaching the ridge of till knobs to the west a change in color of the topsoil illustrates the change from muck soil (developed from the bog deposits), to Canandaigua soils developed from underlying lake silts and clays) to Cossayuna-Troy soils (developed from the till that underlies the lake deposits).

Drumlinized till ridges
Turn left (south) on the Pulaski Highway following the series of drumlinized till ridges.

STOP A-2 Lodgment Till
Examine the lodgment till exposed in the cut behind the Big Island Garage. This till appears similar in lithology, weathering profile and soil development to the Olean till of western New York.

Distal face of the Pellets Island Moraine
Note the distal face of the Pellets Island Moraine to the front and left. (North)

Proximal slope of the Pellets Island Moraine
The proximal slope of the Pellets Island Moraine is to left.

STOP A-3 Pellets Island gravel pit
This is the Pellets Island gravel pit of the Orange County Sand and Gravel Co. The undisturbed foreset bedding on the distal side of the moraine suggests deposition into the open water of the 500 foot lake level. Exploratory cores for the City of New York Port Authority show almost 100 feet of lake clay, overlain by 0-20 feet of organic muck south of the moraine. Large blocks of flow (?) till are periodically exposed on the proximal side confirming it as an ice-contact face.

STOP A-4. Berkman bog
Leave the buses and cross the road to the west. Walk up the gentle slope parallel to the stonewall until the trail becomes clear in the orchard. Follow the trail for about 1/4 mile before descending into the Berkman bog. The implications of the pollen record will be discussed in relationship with the deglaciation of the region and the drainage history of the bog.

STOP A-5. Phillipsburgh crevasse filling
Leave the buses and gather on the hill on the right side of the road. Observe the Phillipsburgh crevasse filling that trends to the northwest toward the Wallkill River. QUESTION: Why are there no drainage features nor ice-contact deposits to the south and east of this feature?

Crevasse filling on the left
Continue northwest parallel to the crevasse filling on the left and Route 17 on the right.
2010: Route 17 truncates the route shown on the Road Log. Returning to where Owen's Road crosses it gets us to the lunch stop.

Bridge across the Wallkill River.
The river flows on bedrock on the east bank.

STOP A-6 Gravel Pit
This is one of the gravel pits operated by E.Tetz & Sons. Examine the pebble lithology as contrasted with that seen at Stop A-1. QUESTION: What is the significance of the large boulders of Shawangunk conglomerate?

STOP A-7. Large Kettle Hole
Cross through the barbed wire fence on the left side of the road and proceed up the hill to the large kettle hole. Here the significance of the stagnant ice topography found in the Wallkill Valley will be discussed.

Plain of washed till
Turn left (east) on Stoney Ford Road. The road traverses a plain of washed till adjacent to the Wallkill River.

Kame complexes
Turn left (north) at the Stop Sign and drive through more kame complexes similar to stops A-6 and A-7.

Distal slope of the Circleville Moraine.
Ascend the distal slope of the Circleville Moraine. The relationship of this moraine to the Pellets Island and New Hampton Moraines is uncertain.

STOP A-8.
This is one of a number of gravel pits operated by the Dickenson Sand and Gravel Co. of Bloomingburg. Examine the drift lithology. The significance of the numerous crevasse fillings in the Shawangunk Kill Valley north of Otisville will be discussed.
2010: Construction of Route 17 truncates the route given in the road log. The path here will get to the same entrance onto Route 17.

Chester crevasse filling and Chester Moraine
The Chester crevasse filling and Chester Moraine are seen on the left. Camp La Guardia is located on the Chester Moraine.

Mass Wasting
Note the mass wasting evident in the till cut to the right.

Valley-choker Moraine
Note the massive valley-choker moraine to the right. This pit once displayed magnificent forest bedding toward the south.

B: THE ECONOMIC GEOLOGY OF THE MID-HUDSON VALLEY REGION
A diverse terrain endowed with a wide variety of available mineral resources, sustained demand for these resources and economical means of transportation have combined to foster a dynamic mineral industry in the Mid-Hudson Valley region which has prospered since the early 19th century. Production valued at about 100 million dollars in 1965 accounted for approximately one-third of the State1s entire mineral economy. Of greater significance is the fact that the Mid-Hudson Valley's mineral production is concentrated in less than one percent of New York State1s total land area (47,944 square miles). The principal products are crushed stone aggregate, building stone, lightweight aggregate, sand and gravel, portland cement, natural cement and brick - materials all necessary to building and highway construction.
Systematic geologic studies of the nature and use of rock raw materials have produced revolutionary changes in the economics of industrial mineral production in the Hudson Valley during the last decade. The result has been an increase of crushed stone reserves by a factor of 3 to 5, cement reserves by a factor of 5 to 10 and lightweight aggregate reserves from nothing to well over a billion tons. This represents another example of taking what is available and utilizing it all, by separation or by blending, for the most useful purpose. The economic rock section ranges in age from Cambrian to Middle Devonian (Tables Bl and B2).
Trip B is specifically planned to allow participants the opportunity to examine in a day's time the greatest variety of rock raw materials and mineral commodities typical of the Mid-Hudson Valley. The following U.S. Geological Survey 7 .5-minute topographic quadrangles cover the route of the trip in order: Newburgh, Wappingers Falls, Poughkeepsie, Hyde Park, Kingston East, Kingston West, Rosendale and Clintondale.
JOHN H. JOHNSEN
Vassar College
SIMON SCHAFFEL
The City College of New York

B: THE ECONOMIC GEOLOGY OF THE MID-HUDSON VALLEY REGION

STOP 1: Shale quarry and clay pit
Shale quarry and clay pit of the Beacon Brick Corporation Exposed in the quarry are grayish-black, red and green slaty shales of the Normanskill Formation (Table Bl) which are blended with clay to manufacture brick. Note slaty cleavage parallel to bedding. Hudson Valley brick is produced by either the "soft mud" or "stiff mud" process. "Soft mud" brick is made from clay to which an excess of water has been added to secure plasticity. The soft mud is placed in wooden molds which have been dusted with sand and the clay is allowed to dry before firing. Extreme care must be exercised to avoid drying cracks and shrinkage. The "stiff mud" process is used most frequently by the modern brick industry. Highly plastic clays are undesirable for this process so that ground shale is usually added to the mix. The stiffer clay or clay-shale mix is extruded through a rectangular die and bricks are cut off by taut wires. These unfired bricks, being stiffer, can be handled with less danger of deformation. Proceed to clay pit. Exposed in the pit is clay that represents fine mud deposited in one of many meltwater lakes that occupied the Hudson Valley during the retreat of the ice in the Late Pleistocene. The clay is normally bluish gray but it may be yellow when weathered due to the oxidation or iron. Thin beds and lenses of sand are frequently inter-stratified with the clay. The thickness of the clay is variable in this region, but it may exceed 200 feet in some localities. This glacial clay is well adapted to brick manufacture. It is plastic and usually has sufficiently large proportions of fluxing agents - such as alkalies, iron, lime and magnesia - to permit vitrification at relatively low temperatures. The finished product is generally red or pink in color. The Beacon Brick Corporation uses a clay-shale mix to make extruded wire-cut brick. Firing takes place in a tunnel kiln having a capacity of 100,000 bricks per day. The chief market area is New York City with transportation by barge. Lightweight aggregate is manufactured from shale or clay by heating these materials until they expand to form porous, scoriaceous material by the evolution of gas bubbles at elevated temperatures (see Stop 3). The Normanskill Shale is considered a potential source of lightweight aggregate raw material; however, pilot tests of the shale from this area yielded an unsatisfactory product because of the lack of compositional uniformity and the large amount of micro- and mega-structural diversity. The slaty cleavage caused slivery rather than equidimensional fragments on crushing which produced a pleated appearance on bloating similar to expanded vermiculite. Although this structure does not necessarily result in an aggregate of low strength, it does make a less attractive aggregate in terms of consumer acceptance. So far as is known, there has been no attempt to produce lightweight aggregate from Hudson Valley clay.

STOP 2: Clinton Point Quarry
New York Trap Rock Corporation, Clinton Point Quarry Plant Office and loading dock. Hard hats will be loaned to those participants not bringing them. The borrowed hats will be returned at Nytralite Aggregates, Inc. (Stop 3).
Two belts of dolostone suitable for crushed stone aggregate occur along the Hudson River in the lower reach of the Mid-Hudson Valley (see Lower Hudson Sheet, Geologic Map of New York State, 1961). The southern most of these two belts follows the northern margin of the Hudson Highlands north-northeast from the vicinity of Beacon to the eastern portion of Dutchess County where it veers more northerly, eventually crossing into northern Connecticut and Massachusetts; the other belt begins B6 southwest of Newburgh and also trends north by northeast to cross the Hudson at New Hamburg (situated at the mouth of Wappinger Creek) where it occurs in two distinct bands over a short distance and continues in the same north-northeasterly direction to the upper part of Dutchess County.
The rocks take their name, Stockbridge Group, from Stockbridge, Massachusetts, where the northeastern extension of the southernmost belt has been metamorphosed to marble. In the field trip area, the carbonates are unaffected by metamorphism and frequently are referred to as the Wappinger Group, a name well established in the literature. The Stockbridge succession includes carbonate rocks that are Late Cambrian to Early Ordovician in age although that part of the succession in the vicinity of the Hudson River may be all Cambrian. The sequence includes a series of dense to finely crystalline, gray dolomitic rocks ranging from dolomitic limestone to dolostone which collectively are calcitic dolostones.
At Clinton Point, the rock is dolostone, with a magnesium carbonate content of 38.16 percent. Here the New York Trap Rock Corporation, a subsidiary of the Lone Star Cement Corporation, produces every conceivable size of stone ranging from riprap to stone sand and screenings.
The quarry opening is effectively blocked from river view by a 500-foot wide buffer zone or "mercy strip". The dolostone reportedly extends to considerable depth and a portion of the quarry floor is now 60 feet below the level of the Hudson River. Downward development is possible because the rock in the buffer zone is sufficiently tight to hold back the river water.
Two inactive quarries are located in a different part of the dolostone sequence on the west bank of the Hudson opposite New Hamburg at Cedar Cliff. In these quarries the dolostone is locally characterized by considerable chert of a variety that is known to have a deleterious effect when used as concrete aggregate. If reopened, selective quarrying would be necessary until new advances in concrete technology nullify these effects. There is no reason why other applications are not possible, provided the rock meets the necessary specifications.

STOP 3: Nytralite Aggregate, Inc. Quarry
Nytralite Aggregate, Inc. - Quarry and Tour of Plant Nytralite Aggregates, Inc. is one of the leading producers of lightweight aggregate in the Mid-Hudson Valley. Lightweight aggregates are special materials incorporated with cement in the manufacture of concretes- which range in weight from 120 pounds per cubic foot to less than 62 pounds per cubic foot. The latter is able to float on water. By comparison, conventional concretes containing other aggregates, such as crushed carbonate rock seen at Stop 2, weigh about 150 pounds per cubic foot. Lightweight aggregate is used in substantially more than half of the concrete block produced in the United States. The desirable properties gained by this usage are: lightness, high strength-to-weight ratio, low shrinkage, low thermal conductivity, good acoustical properties, a coefficient of expansion similar to that of steel and low production costs. The use of lightweight aggregate in the concrete roadway of San Francisco-Oakland Bay Bridge reduced the cost of steel by three million dollars. Lightweight aggregate may be manufactured from clay or shale by heating these substances until they expand to form porous, cinder-like materials. Expansion is a bloating process in which two conditions occur simultaneously. Upon firing, the clay or shale fuses to form a viscous liquid, while at the same time, a gas, released as a result of mineral decomposition, becomes entrapped within the viscous mass. If the gas-producing mineral, or minerals, decomposes before any appreciable liquid formation takes place, expansion will not occur, as the gas will escape through the open-pore structure. Satisfactory expansion also will not occur if the gas is evolved at temperatures much greater than the softening point, as the gas will again be lost because the melt will be too fluid to retain it. If, for some reason, the gas is retained under this condition, cells may be too large and their walls too thin for good strength. Non-bloating argillaceous materials can often be induced to expand by adding pulverized coal and pelletizing into desired size prior to ignition. The rock most suitable for the manufacture of lightweight aggregate is a massive, somewhat silty (arenaceous); unweathered shale of uniform quality. It may contain a small amount of calcite, either disseminated or as thin veinlets, and a little pyrite. Slaty cleavage should not be well developed, but it causes no problem in its incipient stages. This type of rock yields a good, uniform aggregate of adequate strength and an acceptable appearance. It bloats at approximately 2000 degrees F. The Esopus Shale exposed in the Nytralite quarry fits this description. Note the gentle dip of the massive beds to the southeast (north face) and nearly vertical cleavage (east face). The quarry is located on the gently dipping western limb of an asymmetrical syncline, the axial planes of which dips to the southeast. The trace of the axial plane is roughly parallel to the crest of Fly Mountain. Fly Mountain is basically a northeast-trending asymmetric synclinal ridge characterized by a number of similarly-trending subsidiary folds. It is composed mainly of Late Silurian and Early Devonian carbonate rocks {Figures B3, 84} which have been thrust northwestward over the Esopus Shale along multiple faults. Exit quarry. Cross Route 32 and proceed up road to plant. Exit buses and proceed on foot. Note initial test quarry in Esopus Shale to north. Walk up hill, noting the carbonate rocks, to primary crusher and Plant Office. Route essentially parallels the section given in Figure B4. Plant Office. Lunch stop and tour of plant. Refer to flow diagram {Figure B5}.

STOP 4: Natural Cement Mine, Century Cement Mfg. Co.
Natural cement is produced by calcining an impure, argillaceous limestone or dolomitic limestone containing from 15 to 40 percent silica, alumina, and iron oxide at a comparatively low temperature (about 14000 F.) so that decarbonation but no fusion takes place. The burned mass will not slake if water is added, but when ground to a powder it will harden rapidly with the addition of water. Natural cement acquires most of its untimate strength in 5 years and only one-eighth of its ultimate strength in 7 days whereas most portland cements approach their ultimate strength in one year and reach 65 to 75 percent of their ultimate strength in 7 days.
In the United States, the cement industry began in 1818 with the discovery of natural cement rock near Chittenango, New York, by Canvass White. White applied to the State of New York for exclusive rights to manufacture the cement for 20 years. His request was denied but the State awarded him $20,000 in recognition of his valuable discovery. The cement was used in the construction of the Erie Canal.
In 1825, during the building of the Delaware and Hudson Canal, a natural cement rock was discovered here at Rosendale. Work was progressing along the route of the canal through the farm of Jacob L. Snyder when it became necessary to blast through some rock. The rock, as blasted, had the appearance of limestone and fragments were taken to a blacksmith shop at High Falls to produce lime. The stone was burned in the forge and attempts to slake it were made by adding water. The calcined material, soft and chalky after burning, did not slake but instead, after a few hours, lost all of its chalkiness and began to harden. It had been planned to obtain the cement necessary for the canal locks from Chittenango but with the discovery of cement along the route, a contract was awarded to a Mr. John Littlejohn to supply the canal's needs. Littlejohn built a "pot" kiln in which the burning of each charge was a separate operation. The pot kiln was a shaft excavated in the side of a hill and lined with cement rock. At the base of the kiln, an "eye" or shaft at a right angle to the main shaft was filled with cordwood and an arch of large cement rocks, to act like a grate, was formed just above the cordwood. The kiln was then filled with cordwood and an arch of large cement rocks, to act like a grate, was formed just above the cordwood. The kiln was then filled with broken cement rock and the cordwood ignited. The burning continued until the highest stone in the kiln was calcined (5 to 6 days) and then the entire charge was withdrawn. The kiln was then recharged and the procedure repeated.
The charge, as drawn, contained some raw and some over-burned materials. These were carefully removed and the raw material was used in the next kiln charge while the over-burned material was discarded. This procedure was necessary not only from a technical standpoint but also from a mechanical one. The mill equipment would grind neither the hard over-burned clinker nor the hard under-burned stone. The grinding equipment was fashioned on the same principle as a grist mill, utilizing millstones made from the quartz pebble conglomerate or "grit" of the Shawangunk Formation. The growth of the natural cement industry fostered a sizable millstone business. The rocks in the Rosendale district are so intricately folded and faulted that natural cement raw materials crop out almost everywhere. Repeated exposures are clearly indicated by the many abandoned mines in the region and it is obvious that the early miners knew what to look for. The natural cement rock was at first quarried but eventually it became necessary to drive headings and open a mine where the dip carried the desired rock below the surface. To aid visibility, it was customary to mine down dip a certain distance, return to the outside, and create a similar new opening 30 feet or so along the strike. These headings would then be worked at right angles until they were connected. The procedure was repeated again and again, leaving a series of adits, which provided the light to work with, separated by 30-foot pillars. As it became necessary to penetrate deeper underground, illumination was provided by kerosene torches and the miners copied from their successful adits the scheme of leaving 30-foot pillars to support the roof. This room and pillar arrangement is clearly demonstrated in the Century Cement mine.
Natural cement production in the United States grew from 100,000 bbls. a year in the 1830's to 10,000,000 bbls. per year in 1899. At the peak of the industry, in the Rosendale district, some 20 plants employed 5,000 men and turned out 4,000,000 bbls. per year.
About 1894, portland cement, a carefully controlled blend of cement raw materials to insure uniformity, came into general use. In 1900 production of natural cement and portland cement was identical, 8,500,000 barrels each. During the early 1900's, the first large structure of its type to be entirely constructed with portland cement was the Boonton Dam in New Jersey. The Boonton Dam was to be a part of the water supply of Jersey City and Rosendale natural cement was originally specified for its construction. However, a director of the Alpha Portland Cement Company was a member of the Board of Water Supply and he proposed to supply the Jersey City job with portland cement from his company at the same cost as Rosendale natural cement. The dam was built with portland cement. Then portland cement gained ascendency over natural cement and by 1910 natural cement production throughout the United States was reduced to about 1,000,000 bbls. The plants began to close down after the start of the 20th century and by 1920 only one plant remained in the Rosendale district - Century Cement. In fact, this company is the only producer of natural cement in the United States today and that on a limited basis. The natural cement produced in the Rosendale district is a low lime, high silica, high magnesia, hydraulic cement of pozzolanic properties. A typical chemical analysis of the raw cement rock (Rosendale Member of the Rondout Formation) mined by Century Cement is:
SiO2 | 17.5
Al2O3 | 5.0
Fe2O3 | 2.8
CaCO3 | 41.5
MgCO3 | 31.5
Alkalies | 1.7
| 100.0%
The working faces are now about half a mile from the mine entrance and slightly more than 100 feet below the surface. Production is presently limited to the Rosendale Member.
A significant portion of the mined-out lower level has been leased for the underground storage of vital records. Construction of vaults and other preparations are in progress.

C: MIDDLE AND UPPER DEVONIAN CLASTICS OF THE CATSKILL FRONT, NEW YORK
The Middle and Upper Devonian of the Catskill Mountains region of southeastern New York consist of approximately 8000 feet of strata which commence with limestones at the base and grade upward through black shales, gray siltstones, gray sandstones, red beds, and, at the top, conglomerates (Fig. 3). The lowermost 2000 feet (Onondaga, Bakoven, and Ashokan Formations) are described by Chadwick (1944, p. 94-116). The purpose of this field trip is to examine the red bed-gray sandstone and conglomerate facies or depositional phases (Rickard, 1964) that have been referred to as "Catskill."*
*Rickard (1964) calls the conglomerate phase "Pocono."
FRANK W. FLETCHER
Susquehanna University

C: MIDDLE AND UPPER DEVONIAN CLASTICS OF THE CATSKILL FRONT, NEW YORK

STOP 1. (15 minutes) Onondaga Limestone (Middle Devonian).
This is primarily a stop for introduction to the basic Middle and Upper Devonian stratigraphic sequence of the Catskill Mountains region (see p. C1-C8). The Onondaga at this locality consists of very cherty, fossiliferous limestone. It dips toward 258° at 13°0 and forms a low escarpment. An excellent panorama of the chief physiographic elements of the region can be observed from this location. The topographic depression directly west of the Onondaga escarpment is Bakoven Valley, which is underlain by the relatively soft black shales of the Bakoven Formation. The low Hoogeberg range west of Bakoven Valley is composed primarily of resistant siltstones of the Mount Marion Formation and is capped by the Ashokan Sandstone. The plain beyond the Hoogebergs is underlain at its most easterly part by the upper Ashokan Formation and at its westerly edge by red beds of the Plattekill Formation. Towering above all of these elements is the Catskill Front; and, beyond, the high peaks of the Catskills including Slide Mountain, Wittenberg Mountain, and Cornell Mountain, whose summits are composed of the Slide Mountain conglomerate (Fig. 4).

STOP 2 (60 minutes) Manorkill and Gilboa Formations.
Buses will allow field trip participants to disembark and then will drive to top of section. Participants will walk along right (north) side of highway to top of section. CAUTION: Road is narrow, so "cling" to side.
The upper part of Kaaterskill Creek can be seen approximately 0.2 miles northeast of this locality. This is the location of Prosser's classic example of stream piracy, where the headwaters of Schoharie Creek were captured by the much-steeper gradient Kaaterskill Creek.
Figure 13 describes the stratigraphic section of this stop. Many of the typical rock types and sedimentary structures of the lower Catskill facies can be observed here. Especially note-worthy are the fining-upward cycles discussed on page C1.

STOP 3 (90 minutes) CONTINENTAL SEQUENCES IN THE PROXIMAL GENESEE GROUP
LUNCH (40 minutes) Guest Lecture by PETER J.R. BUTTNER Computing Center, University of Rochester
Follow NYSGA trail markers along rim of Catskill Front to outcrop of the "Twilight Park Conglomerate." CAUTION: Watch your footing along the Front. Please remain at least five feet back from the edge of the cliff. NO SPECIMENS MAY BE TAKEN FROM WITHIN THE PARK BOUNDARIES.
Trail lies on strata of the lower Oneonta Formation. Note crossbedding, excellent jointing and joint-controlled face of the Catskill Front. An excellent view of the Hudson Valley, the low Taconics, and, on very clear days, the Berkshires is available from the Front.
Return along trail to buses and field trip headquarters.

D:UPPER SILURIAN-LOWER DEVONIAN STRATIGRAPHIC SEQUENCE, WESTERN MID-HUDSON VALLEY REGION, KINGSTON VICINITY TO ACCORD, ULSTER COUNTY, NEW YORK
The remarks concerning the Upper Silurian and Lower Devonian stratigraphic units described in this paper largely pertain to strata within the Field Trip area (Fig. 1) extending in a belt from Accord (Stop 9) northeast to just beyond Kingston (Stops 1 and 2). The entire belt appears to be underlain with angular unconformity by a disrupted sequence of graywackes and shales to the northeast (Austin Glen affinity) and shales and siltstones to the southwest (Snake Hill affinity). The relations of these two lithologic groups in this area are not clear but it does seem that both were somewhat uplifted and folded (if not faulted) during the Taconian Orogeny; by latest Middle Silurian (?) the Ordovician sediments and structures were eroded to a surface of seemingly low relief or uniform slope. Subsequently a sequence of conglomerate (Shawangunk), shale (High Falls), sandstone (Binnewater) and carbonate (Rosendale-Wilbur) was deposited on the erosion surface in an apparent, general progress ion to the north east.
From Rosendale-Wilbur times through the remaining Late Silurian and Early Devonian the region was generally covered by marine waters, although intertidal and supratidal conditions existed intermittently on a local to regional scale. The Late Silurian and Early Devonian strata are relatively uniform in lithology and thickness throughout the area but some local and regional differences in depositional environments are evidenced within the Rondout, Thacher, Connelly and perhaps other formations. Apparent throughout the Rondout-Lower Devonian sequence is a more or less rhythmic alternation of variously interrelated, high energy-low energy, clay-carbonate, "shallow water"-"deep water", marine environments of deposition.
RUSSELL H. WAINES
S. U. N. Y. College at New Paltz
FLORENCE GROSVENOR HOAR
Winthrop, Maine

D:UPPER SILURIAN-LOWER DEVONIAN STRATIGRAPHIC SEQUENCE, WESTERN MID-HUDSON VALLEY REGION, KINGSTON VICINITY TO ACCORD, ULSTER COUNTY, NEW YORK

Toll Booth, NYS Thruway Interchange 17 (Newburgh).
Proceed north (right) onto Thruway toward Albany. Between Newburgh and New Paltz occur occasional road cuts in Ordovician (Martinsburg-Snake Hill (?)) slates and siltstones. Note the generally progressive decrease in degree of foliation of the beds northward.

NY 299 overpass near NYS Thruway Interchange 18 (New Paltz).
North of New Paltz the degree of foliation in several extensive road cuts in the Ordovician shales is much less pronounced than further south. A fauna found in Ordovician beds north of New Paltz shows affinities with that of the Snake Hill Shale (Late middle Ordovician).

Wallkill River
Wallkill River cutting Ordovician shales and siltstones on the right.

Rondout Creek cutting Ordovician shales and siltstones.
Rondout Creek cutting Ordovician shales and siltstones. Lefever Falls (rapids) on the left. This is about the northernmost extent of Ordovician outcrops along the Thruway in the field trip area (Fig. 1).

Underpass NY 32.
For the next 5.3 miles there are intermittent outcrops and road cuts in a more or less regularly ascending order of formations from Kalkberg (Lower Devonian) through Onondaga (Middle Devonian). High speed traffic does not permit close observation.

Esopus Creek.

Extensive road cuts
For the next 2.1 miles are extensive road cuts in gently dipping siltstones and shales of Mt. Marion Formation (Middle Devonian).

Mt. Marion (?) outcrop north of road and east of creek.
Bridge over Esopus Creek.

STOP 1: Road Cuts
STOP 1a: Road Cut in Esopus and Schoharie Formations. Pull off onto north side of highway with care. On this trip (Stops 1A-C) do not cross over onto south side of highway because of high speed traffic. Observe anticlinal exposure of upper (40-45') of Esopus Shale to the west and synclinal exposure of Schoharie Formation to the east. Contact between the two formations is covered but contacts, lithologies and thicknesses of the Carlisle Center, (including Black Bed), Aquetuck and Saugerties Members of the Schoharie can be observed. Fossils are best collected from the Saugerties Member. Sections of the feeding burrow Zoophycos cauda-galli are common in the Esopus Shale and Carlisle Center Member. Total extent of road cut is about 0.3 miles. Proceed east on foot along north side of highway right-of-way about 0.5 miles to the next stop.
STOP 1b: Road Cut in Glenerie, Port Ewen, Alsen and Becraft Formations: In this anticlinal exposure a partial section of Glenerie Formation and complete or almost complete sections of the Port Ewen and Alsen Formations can be closely examined on the western flank. A partial section of Becraft Limestone is exposed in the core of the structure. Although the contact between the Glenerie and Port Ewen Formations is covered, the Connelly Sandstone which intervenes to the south does not seem to be present here. The Port Ewen-Alsen-Becraft contacts are well-exposed. Some fossils can be collected in the Glenerie, Alsen and Becraft Formations. This road cut extends about 0.1 miles.
Proceed east on foot along north side of highway right-of-way about 0.2 miles to the next stop.
STOP 1c: Road Cut in New Scotland, Kalkberg, Ravena and Thacher Limestones: In this road cut a sequence of west-dipping beds are exposed. From west to east these are: the New Scotland Formation (incomplete); the Kalkberg Limestone with its two members, the Broncks Lake and Hannacroix (complete); the Ravena Limestone, sole representative member of the Coeymans Formation (complete); and the Thacher Limestone, sole representative member of the Manlius Formation. The Thacher-Ravena-Kalkberg and possibly Kalkberg-New Scotland contacts are well-exposed. Fossils can be collected from all formations or members, but especially the New Scotland Formation. The brachiopod Gypidula coeymanensis is noteworthy in the Ravena and Hannicroix limestones but is difficult to obtain whole. Stromatoporoids are noteworthy in the Thacher Limestone.
This road cut extends about O. 1 miles.

STOP 2: Wilbur, Austin Glen, Roundout, Thacher, Revena fms
STOP 2a: Road Cut Exposing Wilbur Limestone - Austin Glen (?) Graywacke Angular Unconformity: Because of high speed traffic please do not cross highway on this trip. Here is exposed a slightly folded, but largely horizontal, bed of Wilbur Limestone (lowermost member of the Rondout Formation) in distinct angular unconformity with underlying graywackes of possible Austin Glen affinity. It is possible that the unconformity is actually a fault but the same relations obtain too often elsewhere to make this likely. Some fossils may be extracted from the Wilbur Limestone. Coenites is abundant locally.
Proceed with care on foot south along NY 32 about O.1 miles.
STOP 2b: Road cut, Austin Glen (?), Rondout, Thacher and Ravena Formations and Members with Structural Complications. Watch for falling rocks. This road cut extends for the next 0.3 miles. Starting from the north end there is a stratigraphic succession from Austin Glen (?) through Ravena Limestone which is somewhat complicated in the north half of the cut by faulting. Individual stratigraphic units are well exposed but Figure 4 should be consulted in order to verify their structural relations. The following Formations or Members are present and their lithologies and contacts (/) indicated:
Ravena ls./Thacher ls./Whiteport dol./ Glasco l./ /Rosendale dol./Wilbur ls.?Austin Glen (?) graywacke
A few fossils may be collected from all units except perhaps the Whiteport and Rosendale dolomites and the Austin Glen (?). Especially noteworthy are Cystihalysites and stromatoporoids in the Glasco limestone.

Intermittent Outcrops and Road Cuts
From the south end of STOP 2b (39.4 miles) south to the intersection of NY 32 and US 9W (42.3 miles) there are intermittent outcrops and road cuts in a more or less regularly ascending stratigraphic order from Austin Glen (?) through Onondaga Formations. The overall picture is somewhat complicated structurally. Of especial note however, is a two to three foot bed of Connelly Sandstone exposed at the south end of a road cut on the east side of the highway about mile 40.6 of this trip. Traffic does not permit close observation from a bus.

Trailways bus depot. Rest Stop.

STOP 3: City of Kingston Wilbur Gravel Pit
Standard Reference Section of the Rondout Formation and Type Section of the Wilbur Member; Intercalation of the Wilbur Member with Rosendale Member; Binnewater Sandstone disconformably underlying the Rondout Formation and overlying the Ordovician Austin Glen graywackes and shales in angular unconformity. Walk up road to gravel pit (northeast) about O.1 miles. The cliff to the northwest is formed of an extensive sequence of Upper Silurian and Lower Devonian strata (mostly carbonates) partly repeated by faulting. Rickard (1962, p. 30) suggested that the standard reference section for the Rondout Formation be located in this quarry and Hoar and Bowen (1967, p. 4) designated this locality as the type section for the Wilbur Limestone Member which here inter-tongues with the Rosendale Member (Fig. 2). Disconformably underlying the Rondout Formation is the Binnewater Sandstone which is absent further north (STOP 2a, 2b) and which, at the present stop, overlies graywackes and shales of Austin Glen (?) affinity with angular unconformity.

STOP 4: Road Cut NY 32, Bloomington Vicinity; Glenerie, Connelly and Port Ewen Formations:
Here is exposed an almost continuous sequence of northwest-dipping beds of the upper part of the Port Ewen Formation (up hill) through the Connelly Sandstone into the lower part of the Glenerie Formation (downhill). The Connelly Sandstone has thickened considerably from the two or three foot exposure about one mile south of Stop 2a. Layers of abundant brachiopods exposed in section can be seen in the Glenerie limestones but collection in the round will prove difficult.

STOP 5: South End Quarry Hill
Binnewater Sandstone - High Falls Shale - Shawangunk Conglomerate - Snake Hill ? Sequence: Examine the disturbed siltstones and shales of Ordovician Snake Hill (?) aspect then examine the northwesterly dipping partly covered sequence of beds between the quarry and the edge of the mine pit to the west. Don't crowd edge of pit! From west to east the formations present are: Binnewater Sandstone (partly covered), Highfalls Shale (largely covered), Shawangunk Conglomerate, Snake Hill (?) shales and siltstones. The Binnewater-High Falls contact is covered but the High Falls-Shawangunk-Ordovician shale contacts are fully exposed. Noteworthy is the two to three foot thickness of Shawangunk Conglomerate and its relatively dark color (typical of the top of the formation locally). Also of note is the first two or three feet of shale beneath the conglomerate. This shale seems to differ from more typical Ordovician shales which underlie it. The mine pit to the west is excavated in a fault-complexed body of Rosendale Dolomite. The far wall (west) of the pit from bottom to top reveals a normal sequence of Glasco Limestone (ledge), Whiteport Dolomite (lower portion mined out) and lower part of the Thacher Limestone (upper part of the cliff).

Abandoned natural cement kilns on roadside to right.
Turn sharp left into open field and head toward distant kilns to the west by following dirt road left then right.

STOP 6: Fourth Lake; Rosendale Member Type Section
Fourth Lake; Rosendale Member Type Section; Ordovician, Snake Hill (?) Shale, High Falls Shale; Rondout Formation; Thacher Limestone (part) Sequence:
Park in front of kilns. Walk uphill to the right (north) over a glaciated shale outcrop of Snake Hill (?) affinity, then bear northwest over rubble pile and continue west at top of hill to New York Central Railroad tracks. Total distance is about O.1 miles.
Walk north right about 0.05 miles along track to railroad cut in Ordovician shales of Snake Hill (?) affinity. Retrace steps south about 0.07 miles along west side of track examining soil of covered interval for first signs of red shale particles (High Falls). Because traces of the Shawangunk Conglomerate are lacking and because the formation is not exposed locally, it is assumed that the High Falls Shale is in direct contact with the Ordovician shales even though the contact is covered at this Stop and not exposed locally. Continue walking south to the partly covered contact between the High Falls Shale and the Binnewater Sandstone. For the next O.1 miles in the railroad cut along the west side of the track is exposed a continuous sequence of northwest-dipping strata including uppermost High Falls (north) through Binnewater, Rosendale, Glasco, Whiteport and lower Thacher (south) members and formations. Examine the various units in light of general descriptions in the text. Contacts between units should be observed - some with caution. Except for pillars the bulk of the Rosendale and lower Whiteport members has been mined out. Please do not fall into the pits. Hoar and Bowen (1967, p~ 4) has designated this locality the type section of the Rosendale Dolomite Member of the Rondout Formation.

STOP 7: Williams Lake
Williams Lake; Rondout Formation; Binnewater Sandstone; High Falls Shale; Shawangunk Conglomerate Sequence: For the next 0.1 miles north in the railroad cut on both sides of the track is exposed a continuous sequence of westerly-dipping strata which include the Whiteport (south) through Glasco, Rosendale, Binnewater, High Falls and Shawangunk (north) members and formations. The various units and their contacts (where exposed) should be examined in light of general descriptions in the text. The Shawangunk Conglomerate, apparently absent at Stop 6, is well-developed here as well as locally, but the Shawangunk-Ordovician angular unconformity is not exposed.

Rosendale Hill lies directly ahead.

Century Cement Company natural cement kilns on right.
These are still in occasional operation.

Extensive cliffs on right are formed by New Scotland Formation.

STOP 8: High Falls, NY 213 Road Cut
High Falls Shale - Shawangunk Conglomerate Contact: Examine slightly anticlinal, light-colored exposure of Shawangunk conglomerate along extent of road cut (about 0.05 miles). Note the High Falls - Shawangunk contact at the east end of the cut (uphill) and determine whether it is distinct, conformable, gradational and/or interbedded. Note the dark color of the uppermost conglomerate layer.

Delaware and Hudson Canal
Sign on right noting the discovery of natural cement at nearby Bruceville in 1818. Just ahead is a section of the Delaware and Hudson Canal. The recently formed (1966) Delaware and Hudson Canal Historical Society plans to restore to operating condition some of the canal locks at High Falls. The canal played an important part in the transportation of natural cement and coal in the latter half of the nineteenth century.

High Falls and Central Hudson generating facilities on the right.
The face of the falls is formed of the Glasco Limestone and Rosendale Dolomite members of the Rondout Formation. Extensive exposures of Binnewater Sandstone and High Falls Shale occur from the base of the falls downstream.

Outcrops and Road Cuts
Outcrops and road cuts for the next 0.4 miles reveal a succession of strata from the New Scotland Formation (north end) through the Whiteport Dolomite in the bed of Kripplebush Creek at mile 62.5 (south end).

STOP 9: Abandoned New York, Ontario and Western Railroad Cut at Accord
Glasco Limestone (part), Rosendale limestones and Bossardville ? Formation (Accord Shale) Sequence: Walk a short distance southeast over abandoned road and descend into abandoned railroad cut. Walk to east end of cut. Walk west in cut and observe the following sequence: stromatoporoidal limestone of the Glasco Member overlying highly calcareous Rosendale member (compare with Rosendale at Stops 2, 6 and 8) which contains a highly arenaceous unit at the base and which overlies a laminated soft-weathering argillaceous dolomite and dolomitic shale (compare with Binnewater Sandstone and thin interbedded shales at Stops 6 and 7). The argillaceous, dolomitic beds here are tentatively assigned to the Bossardville Formation. They have also been referred to as the Accord Shale (Fisher, 1960). Extent of cut is about 0.1 miles. Time permitting, visits may be made to nearby quarries in the Rosendale limestones and in the Thacher and Ravena limestones.

Quarry in Rosendale limestones
On left is entrance to quarry largely excavated in Rosendale limestones. Road skirts northwest side of quarry.

Outcrop of Shawangunk Conglomerate on left.

Ascend the Shawangunk Mountains
Begin ascent of the general dip slope of the Shawangunk Mountains. For the next 6.1 miles the Shawangunk conglomerates and orthoquartzites which, in effect, sheath the Shawangunk Mountains, crop out extensively giving rise to typical Shawangunk Mountain topography.

Ordovician shales of Snake Hill (?) aspect
Ordovician shales of Snake Hill (?) aspect on the right. This exposure is part of an Ordovician shale window in the Shawangunk Conglomerate. Several years ago a very deep, very dry, wildcat was drilled in this window.

Lowermost part of the Shawangunk Conglomerate
Bridge underpass. Lowermost part of the Shawangunk Conglomerate is exposed in the road cut just east of the bridge.

Begin descent
Exposure of Ordovician shales of Snake Hill (?) aspect to the left. View of the Mid-Hudson Lowlands to the east and on a clear day, the Hudson Highlands to the southeast. Begin descent of Shawangunk Mountains.

Eastern face of Shawangunk Mountains
Shear cliffs of the eastern face of Shawangunk Mountain cuesta tower on the left, capped by almost two hundred feet of conglomerate and orthoquartzite. These cliffs are much used for practice in mountain-climbing as they present most, if not all grades of climbs. On weekends and holidays the cliffs are well populated with climbers from many states and Canada. The sport is not without risk; at least two climbers have "come off" here in the last three years.

Ordovician shale and siltstones of Snake Hill (?) affinity.
Proceed northeast through countryside underlain by Ordovician shale and siltstones of Snake Hill (?) affinity.

E:GEOLOGIC STRUCTURE OF THE KINGSTON ARC OF THE APPALACHIAN FOLD BELT
The Appalachian orogen when observed in its areal extent from Alabama to Newfoundland shows in its pattern a series of arcs, some bowed northwestward toward the foreland, others bowed inward toward the eugeosynclinal belt. One of the more prominent of these arcs, bowed eastward and southeastward toward the crystalline core of New England, is located at Kingston, New York, its hinge-zone being situated in the old Rondout and Wilbur districts of the City of Kingston. The western extremity of the arc lies in the vicinity of Rosendale, and in its northern extension continues to the environs of East Kingston and the Kingston-Rhinecliff Bridge on the Hudson River.
The type of deformation evident within the Kingston Arc may be of some interest to the structural geologist and the purpose of this field trip is to observe the geologic structure at several localities where exposures are favorable.
GEORGE R. HEYL, S. U. N. Y. College at New Paltz
MORRIS SALKIND, Saugerties High School

STOP I: The Nytralite Quarry on Route 32
STOP I: The Nytralite Quarry on Route 32 is developed in the Esopus Shale. The operations of this company extend on both sides of the highway. Shale is trucked from the quarry floor to the crushers on the ridge of Fly Mountain, where the material is processed. It is then heated in the kiln, causing the shale to expand. A conveyer leads down the south side of Fly Mountain, where the expanded shale is loaded on barges in Rondout Creek to be carried down the Hudson River to markets in the New York City area. Trucks are used to carry the expanded shale to customers in the Mid-Hudson area.
Though the Esopus Shales are not highly resistant to erosion, in this area they commonly are minor ridge-makers. Where exposed, they show as massive blocks whose bedding is difficult to follow, but whose cleavage is readily apparent. The cleavage may therefore be easily mistaken for the bedding in an outcrop.
Both the cleavage and the extensive fracture pattern in the shales is reflected in details of the topography of the region. The strongly-cleaved shales are more easily eroded and the intersection of the cleavage with the accompanying joints results in the appearance of gently sloping planes dipping in various directions where the shales are exposed (Fig. 1 - The vertical lines indicate cleavage).
Where freshly exposed, the shales appear black, blue-black, or olive-brown. Often they show vertical white bands, a result of re-deposition on their cleavage surfaces of some of the minerals dissolved from the shale.
Weathering of the shales will often bring out color changes that emphasize the bedding planes. Occasional lenses or thin layers of other material, e.g., sand, help in the delineation of the bedding. Where the shales have been exposed to weathering, some of those having a greater lime content will show a grayer surface.
At this locality the beds are generally more gently dipping than the cleavage. The response of the shales to folding was not paramount; they show some flexures, but the continued impress of the deforming forces caused the shales to shear rather than to fold. Shear planes present in some cases cut across the cleavage. Where a conjugate set of shear fractures exist they are parallel to the cleavage (Fig. 3). The cleavage is generally parallel to the strike of the beds. However, it should be evident that strike joints will generally merge with the strong cleavage.
Occasional fossil shell fragments can be found in the shales. Nodules of pyrite are frequent.

STOP II: Callanhan's Quarry and Railroad Cut
STOP IIa: Callanhan's Quarry is in the village of Connelly south of Rondout Creek. From the quarry floor, facing northeast, approximately 170 feet of limestones have been exposed by the quarrying operation. There are three areas or"pits" where the quarrying operations take place all at varying distances from the northwest-southeast section line drawn across the quarry floor. In the accompanying section, the pits are labeled by number (Fig. 5).
The limestone, commercially known as "traprock", is crushed to different sizes after being blasted from the walls of the quarry. It is used primarily in various kinds of construction such as road metal for highways, and concrete aggregate for building construction. The Rondout Creek is used to transport bulk shipments of the material.
The limestones show three major high-angle reverse faults cutting through all the beds exposed in the quarrying operation. There are numerous smaller faults. Looking to the southeast, one can see near-vertical faces of limestone. Bedding-surface slickensides are commonly seen in the quarry, for example, between the Alsen and Becraft units and within the New Scotland limestones.
The exposed southeast side of Pit I shows an extensive slickensided surface over much of its length. Also on this same surface and extending for many feet parallel to the slickensides are thick, rod-like mullion structures. The limestones in this pit are gently folded.
In Pit 2 there is an extensive fault zone which includes a major fault. Toward the southeast the quarry wall is near-vertical and shows extensive slickensides. There the beds are bent in a circular arc at the southeastern end of this section, and are folded synclinally.
The sharp folds are continued into Pit 3. Here the Becraft-New Scotland exposures are near vertical and show extensive slickensiding within the New Scotland beds.
STOP IIb: This stop is in the cut of the West Shore R.R. about one quarter mile east of Callanhan's Quarry. Near the road coming from the floor of the quarry to where it intercepts the railroad track there are exposures of the Hudson River sandstones. The contact of the Ordovician sandstones and the Silurian is not visible here. The Kalkberg and New Scotland beds can be seen just west of the railroad right-of-way. The Becraft limestone outcrop, to which an abandoned wagon trail leads, was mined in earlier years at this site. Many of the abandoned quarries in the Kingston area formerly exploited the Becraft or the Rondout limestones.
Of the quarrying operations the main evidence is a 100-foot shaft situated between the New Scotland and the Alsen through which the Becraft was removed. At the lowest part of the north wall in this shaft one can see part of the synclinal fold in the Becraft, which was also visible from the floor of Callanhan's Quarry. The railroad cut farther northward exposes the Port Ewen limestone (and its time-correlative deposits - the Connelly). The Port Ewen alternates with the Glenerie in exposures along the railroad tracks.

STOP III: Road cuts along Route 199 three miles north of Kingston.
This stop will be made along that section of Rt. 199 extending between Rt. 32 to Rt. 9W. Along Rt. 199 the road cut exposes relatively gentle folding in the Devonian beds (Fig. 6). There are two low concealed areas in the section which are covered by swamp deposits and alluvium.

Angular Unconformity
Approximately one quarter mile south of the entrance to Rt. 199 on Rt. 32 there is a good exposure of the angular unconformity between the Ordovician beds and overlying Silurian limestone.

STOP IV: Glenerie Falls
This stop is at Glenerie Falls and Rt. 9W approximately 6.3 miles north of Kingston. A plan view of the shear structures and the cleavage in the Glenerie Formation in this area is included (Fig. 4). The pattern which is shown in the plan view is seen as a side view where the Glenerie is visible along the highway. Some of the Glenerie exposures along the highway reflect the shear pattern so that the exposed blocks show as rectangles at times pointing toward the highway and at other times away.
The Esopus Creek which upstream meanders through its valley for several miles turns sharply to the east at Glenerie Falls and then flows north again at the foot of the Falls. Beyond, it continues between the confining Esopus Shales and the Glenerie, and has an approximately straight course almost to its mouth; it makes a bend at Saugerties and flows into the Hudson.
The rocks at the Falls clearly express the shear structure in the area. The weak, overlying Esopus Shales are being rapidly eroded. The presence of the Falls indicates a relatively youthful expression of the topography for the falls have not yet been planed down to grade.

F: STRUCTURE AND PETROLOGY OF THE PRECAMBRIAN ALLOCHTHON AND PALEOZOIC SEDIMENTS OF THE MONROE AREA, NEW YORK
The area covered by this trip lies in the northern part of the Monroe 7 1/2′ quadrangle, New York, and consists of a folded and faulted complex of autochthonous Precambrian gneisses, Lower Cambrian through Middle Devonian sediments and allochthonous Precambrian gneisses. Geologic maps covering the trip area have been published by Ries (1897), Fisher, et.al. (1961), and Jaffe and Jaffe (1962). Unpublished maps prepared by Colony and by Kothe (Ph.D. thesis, Cornell Univ.) undoubtedly contain valuable information but are not available for study. Recent workers in adjacent areas include Dodd (1965), Helenek (in progress) and Frimpter (in progress), all in the Precambrian autochthon, and Boucot (1959) and Southard (1960) in the stratigraphy and paleontology of the Paleozoic sediments. The work of Colony (1933), largely unpublished, is impressive.
HOWARD W. JAFFE, University of Massachusetts
ELIZABETH B. JAFFE, Amherst, Massachusetts

F: STRUCTURE AND PETROLOGY OF THE PRECAMBRIAN ALLOCHTHON AND PALEOZOIC SEDIMENTS OF THE MONROE AREA, NEW YORK

STOP 1: Bellvale Graywacke
The outcrop is on Oreco Terrace, just above the intersection of NY 208 and Oxford Road. Here, the Bellvale graywacke of the Hamilton Group (Middle Devonian) is exposed in a section approximately 220 feet thick. It consists of 20-40 foot beds of dark blue-gray, green-gray, or gray, fine-to medium-grained (.08-.25mm-avge. grain size) lithic arenite or graywacke, rhythmically interbedded with thin beds of dark green-gray to blue-gray shale. A representative modal composition of the graywacke follows:
| |
Detritals | |
| quartz | 20%
| oligoclase | 2
shale
phyllite
44?
siltstone
chert
9.0
| greenstone | 15
Matrix | |
clay, sericite,
chlorite, Mn oxide
15?
Metamorphic | |
| Chlorite | 2
| Muscovite | 1
| | 100%
Texturally, the rock consists of angular, elongated slivers of detrital quartz and predominantly phyllitic rock fragments (.08-.25mm) set in a fine matrix of sericitic muscovite, clay, and chlorite. It is often difficult to distinguish smeared-out phyllitic fragments from balled-up micaceous matrix, both of which frequently blend or flow together. Depending upon the uncertainty of the matrix content, or the classification used, the Bellvale is either a low-rank graywacke (Krynine, 1948), a subgraywacke or a lithic graywacke (Pettijohn, 1957) or a graywacke (Folk, 1954). Larger bent grains of chlorite and muscovite in the matrix, are here interpreted to have grown from fine matrix material, marking the beginning of the chlorite zone - greenschist facies of regional metamorphism imprinted during the Appalachian orogeny.
In general, the Bellvale graywackes tend to show rhythmic interbedding with shale, with graded bedding low in the section and strong current cross-bedding higher in the section. Occasional brachiopods are found low in the section; plant fossils are found higher up. Both features suggest a gradation from marine to nonmarine depositional environment. The provenance was a low-rank metamorphic or sedimentary terrane.
The shattered outcrop at Oreco Terrace is at the southwest corner of Rotated Block 8 (Fig. 2) and lies near the intersection of four directions of faulting. Attitudes of prominent structures at the outcrop are tabulated:
| Strike | Dip | Plunge
Bedding | N 67 W | 30 NE |
Cleavage | N 50 E | 37 SE |
Fault Slickensides | N 13 E | Steep W | 45 N
Fault Slickensides
N 38 E
Steep W
60 N
N 30 W
52 SW
39 W

STOP 2: Shawangunk Conglomerate
Spring Glen Golf Range: Shawangunk Conglomerate
The Shawangunk conglomerate and quartzite (Greenpond conglomerate unit) of Lower to Middle Silurian age occurs in a series of small outcrops extending northeastward along the western edge of the Shunemunk Mountain syncline. At this stop the Shawangunk forms a small, relatively inconspicuous topographic knob as contrasted with its occurrence near Stop 5, where the same unit forms the spine of the steep, southeast-facing escarpment of Lazy Hill. At the present stop the Shawangunk consists of about 75% buff pebble conglomerate intercalated with 25% fine-grained green-gray quartzite.
The conglomerate consists of white pebbles of milky vein quartz (averaging 15-40mm in length) in a matrix of finer pebbles and grains of rounded quartz, all cemented by secondary silica and buff-orange-red ferric oxides. Occasional pebbles of white orthoclase are present as are black pebbles consisting of a mixture of green tourmaline and quartz. The color of the weathered surface of the outcrop varies from pink (hematite) to yellow-brown (goethite) or black (manganese oxide dendrites) with some greens contributed by lichens.
The pebbles, obviously well-rounded when deposited on the Late Ordovician erosion surface, have taken on a secondary angularity and elongation due to stretching, crowding, rotation, and slippage in bedding planes produced during Paleozoic orogenies. Most of the pebbles show maximum elongation parallel to the fold axis (b-direction) and modest elongation parallel to the bedding (a-fabric axis). Many of the pebbles have been corrugated and a large number are cracked and sliced parallel to the b-c fabric plane. Bedding surfaces are slickensided, fluted, and warped parallel to the a-axis (down-dip). The fine-grained, gray-green interbedded quartzite is composed of quartz and minor orthoclase cemented by authigenic quartz, muscovite and chlorite, and Fe-oxides.
The elongation and shattering of the pebbles here and at Lazy Hill to the southwest greatly exceeds that observed in pebble beds in Lower and Middle Devonian rocks (Connelly conglomerate of Oriskany age, and Bellvale graywacke, respectively) in this area, suggesting that the Shawangunk was involved in an additional deformation episode of possible pre-Oriskany age. A pre-Acadian, Silurian deformation period in New York was reported by Megathlin (1939) and discussed by Kay (1942). The sporadic outcrops of Shawangunk quartzite to the north along the western limb of the Schunemunk Mountain syncline are all heavily silicified and sheared, again much more so than quartzites of Oriskany and Bellvale age.
The conglomerate and quartzite outcrop is S-shaped, with the attitudes of the bedding and a cross-fault as follows:
| | Strike | Dip
Bedding, Cgl. | North end of hill | N 8 E | 77 E
Bedding, Cgl. | North center of hill | N 59 W | 70 NE
Bedding, Cgl. | Center of hill | N 27 W | 50 NE
Cross-fault
N 77 W
90
Bedding, Qtz.
South end of hill
N 2 W
60 E
The cross-fault displaces the stratigraphically higher Shawangunk quartzite member to the west, putting it on strike with the lower conglomerate member of the Shawangunk Formation. On first viewing the outcrop, the alternating coarse pebble beds and fine feldspathic quartzites lead one to suspect that the beds are overturned. On close inspection this does not appear to be the case.

STOP 3: Museum Village Klippe
Museum Village Klippe: Allochthonous Pre-Cambrian Leucogneiss Resting On Cambro-Ordovician Wappinger Dolomite
From the Old Mansion Road cut in the Precambrian Museum Village klippe, look south across the N 75° W-trending Quickway crossfault. The ridge due south is the Bellvale synclinal extension of Schunemunk Mountain. The next ridge to the west is Lazy Hill, held up by Shawangunk conglomerate, and offset from the Golf Range Shawangunk conglomerate of Stop 2. To the west of Lazy Hill, the next prominent ridge is the Goose Pond Precambrian klippe, formerly continuous with the Museum Village klippe and now offset about 2 miles along the Quickway cross-fault.
Museum Village klippe is a thin, synclinal, saucer-shaped slice of gray-white albite-quartz-microperthite leucogneiss that has survived five or six orogenies. The rocks of the allochthon were deposited as a clastic wedge (molasse) in a reducing environment, perhaps as long ago as 1500 million years; they were folded and metamorphosed to the sillimanite-almandine-orthoclase metamorphic grade about 1100 million years ago; thrust from the east in Taconic or Late Ordovician time; refolded and faulted in Taconic time; possibly again in Acadian time; refolded and faulted in Appalachian time; and finally shattered by Triassic block faulting and associated block rotation. In outcrop, the leucogneiss is heavily shattered and slickensided with lineations often running in three directions at a given place. Quartz grains and pebbles are stretched into thin corrugated tongues and sheets showing elongations of 15:1 and 20:1 parallel to the b- and a- fabric axes. Over most of the outcrop, biotite and garnet are extensively retrograded to chlorite, and abundant calcite veinlets cross the rocks at all angles.
Towards the central and western part of the cut there occur occasional thin layers rich in fresh biotite and uncommonly coarse laths (not needles) of fresh blue-gray sillimanite that have survived the complex orogenic history. As none of the Cambro-Ordovician or younger rocks in the area show any metamorphic grade higher than chlorite zone metamorphism, the sillimanite is assumed Precambrian in age, and its preservation in large fresh grains in an otherwise extensively retrograded outcrop is remarkable.
The original sedimentary record of Precambrian deposition is preserved in graphite-rich quartzitic layers and in microscopic placer layers rich in apatite, zircon, sphene and ilmenite. In places, volcanic rocks associated with the sediments may be represented by amphibolites such as those in the Bull Mine Mountain klippe to the north.
Modal analyses of samples collected along an east-west traverse across the Museum Village klippe follows:
| East Side | Center | West Side
Andesine (An 32)
-
36.0
32.4
Quartz
Biotite
Almandine-pyrope | 0.1 | 2.0 | - | -
Tourmaline | - | + | + | -
Zircon
+
Ilmenite
The presence of albite in the most retrograded gneisses of this and the other allochthonous Precambrian blocks studied fairly consistently suggests that it may be a retrograded mineral after an originally more calcic plagioclase. The K-feldspar in all of these rocks is microperthite (usually microcline microperthite) and is indicative of a temperature of Precambrian metamorphism of the order of 660° C. The presence of two plagioclases, one as free grains and the other exsolved in microcline microperthite, is characteristic of many of the granitic gneisses of both the autochthon and the allochthons. In some of the allochthonous leucogneisses, the microperthite and the albite tend to occur in separate bands which may reflect original compositional differences.
Park on Oxford Road and cautiously descend hill to the Quickway (N.Y. 17-West = U.S. 6). Beware of high speed traffic and stay close to the outcrop which parallels the highway. Walk to the extreme west edge of the roadcut where the Precambrian leucogneiss rests in overthrust contact on the light gray Cambro-Ordovician Wappinger dolomite. Note the occasional flat-lying, slippery fracture planes at the contact.
The metamorphic layering in the allochthon dips to the east whereas the dolomite bedding dips predominantly west. The average foliation of the leucogneiss is N 33 E,20 SE. The average attitude of the dolomite beds is N 22 W, 35 W. Prominent faults in the klippe parallel the metamorphic layering and trend N 22, E 20 SE. The fault contact of the dolomite and the klippe is irregular and has the same general attitude. Both the dolomite and the klippe are cut by vertical faults trending N 27 W.
Drive west along Old Mansion Road observing the flat topography superposed on the Hudson River pelites. These are more gently folded with increasing distance from the Precambrian allochthon.

Rolling folds in pelites
Cross the Quickway (N. Y. 17) overpass and bear hard left (east) on N.Y. 17-M. Drive about 1.1 miles east noting rolling folds in the Hudson River pelites. Road parallels Quickway fault.

STOP 4:Precambrian Allochthon
Goose Pond Mountain: Precambrian Allochthon Over Overturned Hudson River Pelite
Observe black, fissile Hudson River shales (Middle? Ordovician) in the road cut at the northwest edge of the Precambrian allochthon. Careful observation will show that the attitude of the bedding and cleavage is N 78 E; the bedding dips 70 S and the cleavage 40 S. This indicates that the outcrop is on the limb of an overturned fold with the synclinal axis to the north. The shales both here and at Bull Mine Mountain klippe to the north are all wildly folded and overturned close to the overriding Precambrian allochthons.
Many of the Hudson River black shales are calcareous, and consist of fine laminae (.05-.lmm) of dolomitic silt or mud (marl) intercalated rhythmically (occasionally cross-bedded) with carbonaceous shale. An estimated thin-section mode of a representative Hudson River "shale" follows:
Mineral | Calcareous laminae | Carbonaceous laminae
Detritals and matrix: | |
dolomite, calcite
30%
5%
plagioclase, microcline
10
+
mica, clay, chlorite | 15 | 50
carbonaceous matter, graphite
-
Metamorphic: | - | +
chlorite, muscovite, biotite | - | 5
In the woods about 100-150 feet southwest of the shale outcrop on N.Y. 17-M, moss-covered rubble of shale, dolomite, and "limonitized" fault breccia indicate where the covered contact has been crossed. The edge of the Precambrian allochthon of Goose Pond Mountain is found in place about 130 feet south from the road, and the first rock found in place is a graphitic calcareous quartzite of which sample No. 527 is representative.
Drive 0.4 mi. on N. Y. 17-M, stopping at a white albite-quartz-microcline microperthite leucogneiss (sample No. 20), in places graphitic, biotitic or rarely, garnetiferous. Note the extreme elongation and smearing out of quartz pebbles and grains similar to that seen at the Museum Village outcrop of Stop 3. Further to the east, the rocks become increasingly calcareous (sample No. 788). At the extreme eastern edge, prehnitized calc-silicate leucogneiss is interlayered with some amphibolite, the latter of probable basic volcanic origin. Modes of representative rock types of the Goose Pond allochthon follow:
Modes Of Gneisses Of The Goose Pond Mountain Allochthon
East Side
Center
West Side
Sample Number
Mineral | | | |
brown hornblende | 0.2 | 33.0 | - | -
Here, as in the Museum Village klippe of Stop 2, the greatest amount of retrograding occurs at the eastern and western margins of the allochthon with some fresh rock occurring near the center. If the klippen are indeed synclinal saucers the presently exposed centers of the masses would lie at a further distance from the sole of the thrust and would be expected to show less alteration. It should be emphasized that the Precambrian autochthonous gneisses in the southern part of the Monroe quadrangle (Jaffe and Jaffe, 1962) are not comparably retrograded except near the Triassic border faults.

STOP 5: Shawangunk Quartzite
Walk 0.2 mile west crossing buried northeast-trending fault contact between the Shawangunk ridge of Lazy Hill rising steeply ahead and the Bellvale ridge of Durland Hill to the rear. Walk to the north nose of Lazy Hill (permission of the owners, the Durlands, is necessary) where a large outcrop of Shawangunk quartzite is exposed. The rock is a thin-bedded, pink, buff and white orthoquartzite consisting of:
Mode of Shawangunk Orthoquartzite, Durland Property
Quartz | 93%
Chert
Sericite, Chlorite
Zircon | +
Hematite | +
Goethite | +
Pyrite | +
Green Tourmaline | +
| 100.0%
The quartz grains are well-rounded, moderately elongated, well-sorted (average diameter, 0.75mm), and the rock is very tightly cemented. Each grain of quartz is cemented to another by authigenic quartz overgrown in optical continuity with the detrital cores. Undulatory extinction due to deformation passes through both the core and overgrowth of each grain. The Lazy Hill ridge top to the south (not visited) is formed of a coarse white pebble conglomerate interbedded with white orthoquartzite (occasionally ripple-marked) and grades eastward to a red arkosic conglomerate below the ridge-top. Quartz pebbles and orthoclase pebbles are strongly elongated (3:1 and 4:1) and heavily shattered and veined in both the red arkosic and the white conglomerate.

STOP 6: Connelly (Oriskany) -Esopus Contact
The outcrop at Monroe Bowl-0-Fun consists of about 300 feet of the Esopus Formation underlain at the rear of the cut by red and white pebble conglomerate, the Connelly Conglomerate of Oriskany age. Here, the Connelly consists of weathered, yellow, "limonitic" conglomerate (3' or more), succeeded by white to buff, pebble-bearing orthoquartzite (5'), which is in turn overlain by bright red hematitic quartzite (10'). The pebbles in the Connelly conglomerate are of white, round to slightly elongated quartz, averaging 1-2 mm in maximum dimension. The Connelly is disconformably overlain by a lowermost member of the Esopus Formation, recognized by Southard (1960). The attitude of the bedding of both the Connelly and the Esopus at their contact is N 68 E, 45 N. A heavily slickensided fault surface, trending N 53 E, 60SE cuts across the Connelly beds and presumably also cuts the overlying Esopus Formation.
The lowermost member of the Esopus, at its base, consists of fissile, blue-gray siltstones which weather to brown and orange on cleavage surfaces. Many of the rocks are marked withTaonurus cauda-galli on bedding planes. At this outcrop the authors have collected a remarkable fauna including a specimen of the giant trilobite,Coronura myrmecophorus, not previously reported from the Esopus Formation. According to D.W. Fisher, New York State Paleontologist who identified the specimen, it has previously been reported from the Schoharie and Onondaga Formations. The specimen was donated to the N. Y. State Museum collection.
The lowermost member is also relatively rich in conulariids, none of which have yet been identified. Other fauna include the brachiopods:Leptocaelia flabellites, Schuchertella sp, Acrospirifer macrothyris, as well as some chonetid and orbiculoid genera. Platyostomid and loxonemid gastropods, rugose corals and a dalmanited trilobite were also collected by the authors.
The lowermost member grades into the black, poorly fossiliferous Lower Mudstone member which in turn grades into a purple sandstone at the north end of the 350 foot exposure. The sandstone is presumably the lower part of the Highland Mills member of the Esopus Formation. The fauna of the lowermost member at the Bowl-O-Fun appears to differ significantly from that of the Highland Mills member of the Esopus Formation found at Bakertown and Highland Mills (described by Boucot, 1959). The fauna should receive some serious study by specialists before the outcrop is demolished by new construction.

STOP 7: Poughquag Quartzite (Lower Cambrian)
Orange Turnpike: Poughquag Quartzite (Lower Cambrian)
Walk 0.16 miles due west over hilltop to the edge of a cliff formed by a 10 foot section of the Poughquag Formation (Lower Cambrian). The section consists of alternating 2 inch to 2 foot thick beds of ferruginous orthoquartzite, conglomerate, and arkose, striking N 75 W and dipping 80 N, overlying the vertically dipping Precambrian autochthon with marked angular unconformity. This represents original sedimentary onlap with only gentle warping or folding in subsequent geologic time. Apparently the Precambrian Monroe Massif (Block 2) was sufficiently rigid throughout the Paleozoic to prevent the deformation of the overlapping embayment of Poughquag quartzite and Wappinger dolomite. This is indicated by both the gentle warping observed and also by the relative sphericity of the quartz pebbles in various Poughquag beds.
Several of the beds are feldspathic, a feature uncommon in the Poughquag of the Poughkeepsie quadrangle (Gordon, 1911). One such bed at the Monroe outcrop is a conglomeratic arkose which is a true high rank arkose in the sense of Krynine (1948). A remarkable textural feature of this rock is the abundance of authigenic feldspar (microcline?) which is the principal cementing medium in sample No. 466. The specimen consists of 1-2mm quartz and microcline pebbles (all very round) lying in a matrix of 0.2mm grains of microcline and much less quartz. The microcline grains, each with a dirty outline (Fe and Mn oxides), tend to float in the matrix of authigenic microcline (?) cement which is clear in appearance. Some sawtooth or hacksaw terminations on the detrital microcline cores (Edelman and Douglas, 1931) indicate that interstratal solution has taken place after deposition, presumably in situ. The authigenic feldspar overgrowths show only weak twinning when grown around detrital cores showing strongly developed microcline twinning.
A mode of such rock is as follows:
Mode Of Lower Cambrian Poughquag Conglomerate Arkose
Specimen No. 466
Microcline
47.4%
Microcline microperthite
+
Quartz | 48.6
Albite-oligoclase | +
Muscovite | +
Rutile, Anatse, Tourmaline (green and brown) | 0.5
Zircon | 0.5
Hematite, Mn oxides | 3.0
| 100.0%
The mineralogical composition of the Poughquag at Monroe leaves little doubt that it was derived from erosion of the granitic gneisses it overlies.
On the return walk to the road, stops may be made at exposures of post-Wappinger lamprophyre dikes which the authors believe to be of Late Ordovician age (Jaffe and Jaffe 1962). The authors have studied the dikes in considerable detail and would suggest a possible age of intrusion similar to that of the ultramafic intrusion of the Cortland Complex at Stony Point, New York (Ratcliffe, 1967). The Cortland Complex has been dated by Long and Kulp (1962) at 435 million years by K/ A isotopic ratios obtained on biotite from the complex, a date close to the accepted Ordovician-Silurian boundary.

G: THE PLEISTOCENE GEOLOGY OF THE WALLKILL VALLEY (2)
G.GORDON CONNALLY
S.U.N.Y. College at New Paltz

G: THE PLEISTOCENE GEOLOGY OF THE WALLKILL VALLEY (2)

STOP 1: Ablation Till
Examine the ablation till exposed in the cut behind the Carrol's stand. Compare this till to the lodgment till exposed at Stop A-2 on trip A. There will be a discussion of weathering profile and soil development.

Cross the Catskill Aqueduct
The aqueduct follows the road on the right for 1/2 mile until it is re-crossed. After re-crossing the aqueduct note the lithology of the stone walls, particularly the absence of Shawangunk boulders.

Ascend the till ridge that trends north-south.
This is a ridge of drumlinized crests that can be traced for about 10 miles east of the Wallkill Moraines.

Flat-topped outwash deposit
This road traverses a flat-topped outwash deposit that has a 400 foot crest on the distal side of the Wallkill moraines. This suggests that the ice occupied the Wallkill position during the development of the 400 foot lake level.

Outermost Wallkill Moraine
Ascend the gentle distal slope of the outermost Wallkill Moraine and then descend the proximal slope into the stagnant ice complex.

Cross the first inner Wallkill Moraine.

STOP 2: Wallkill Moraines
STOP G-2. Here can be seen some of the Wallkill Moraines. Their possible relationships and the relation of the Wallkill River to the glacial deposits will be discussed.

The Wallkill Moraines are well displayed on the right

Second inner Wallkill Moraine
Cross the distal slope of the second inner Wallkill Moraine. This moraine is on a bedrock escarpment and is not nearly as massive as the topography makes it appear. The State Prison Moraine (?) is on the left in the distance.

Cross the Catskill Aqueduct.

A striated bedrock knob is exposed on the right.

State Prison Moraine
The State Prison Moraine (?) is immediately adjacent to the road on the left and will be crossed in the vicinity of Ireland Corners.

Splendid panorama
On a clear day a splendid panorama can be viewed on the left. In the foreground is the Lower Wallkill Valley with the Shawangunk Mountain cuesta in the distance. The Catskill Mountains can also be observed on the skyline behind, and north of, the Shawangunks.

STOP 3: Delta remnant
Leave the cars and walk through the field on the left to the sand pit. Examine the relationship between pro-glacial lakes, deglaciation, and the present course of the Wallkill River. This deposit is the remnant of a delta formed in the final 230 foot lake in the Wallkill Valley.

Floodplain of the Wallkill River
The floodplain of the Wallkill River can be seen on the left. The floodplain evidently extends only to the low escarpment a few hundred feet west of the River with undisected lake plain from the scarp to the west valley wall.

Old stone houses
This street contains the old stone houses for which New Paltz is famous. These stone houses were built by the Huguenots in the late 1600's and early 1700's.

Oxbow Lake
As the road bends right and then left it is following an abandoned meander of the Walkill that now exists as an Oxbow Lake. This oxbow may be seen behind the houses to the left.

Lake shoreline
From this point to Stop G-4 Route 32 follows the shoreline of the 230 foot lake. This may explain the frequently exposed bedrock along the east side of the road.

Bedrock channel on right, lake sediment on left
Route 213 joins from the right just south of the bridge over the Wallkill River. Note that the Wallkill is cutting a bedrock channel to the right while flowing over lake sediment on the left.

STOP 4: Wallkill geomorphology
Here will be discussed the geomorphology of the Wallkill River drainage basin and its relation to the Rosendale sand plain.

Descend from sand plain
Descend from 240' on the sand plain to 65' in the Rondout Creek Valley. Bridge across Rondout Creek.

Channel bars
Note the channel bars in the creek; these did not exist before the recent drought.

Cross a remnant of the 200 foot Lake Albany (?) plain.

Fly Mountain fault scarp.
Bear left on Mountain Road and parallel the Fly Mountain fault scarp.

STOP 5: Wilbur gravel pit
This is the Wilbur gravel pit of the City of Kingston. It is the type locality for the Wilbur limestone member of the Rondout Formation (Silurian). Leave the cars on the road and walk up into the pit to examine the relationship between the ice-contact gravels and the slumped, overlying Lake Albany (?) sands, silts, and clays. Examine the pebble lithologies and compare them with those at Stops A-1, A-6, and A-8 on Trip A.

Lake Albany (?) clays crop out on both sides of the Thruway.

Cross Rondout Creek cutting a bedrock channel at this point.

Cross Wallkill River cutting bedrock channel at this point.

NEW YORK STATE GEOLOGICAL ASSOCIATION GUIDEBOOK
TO
FIELD EXCURSION
S 40TH ANNUAL MEETING
AT
QUEENS COLLEGE
CITY UNIVERSITY OF NEW YORK
FLUSHING, NEW YORK

A: BEDROCK GEOLOGY IN THE VICINITY OF WHITE PLAINS, NEW YORK
By Leo M. Hall, University of Massachusetts
(Approved for publication by the Assistant Commissioner for the New York State Museum and Science Service.)
INTRODUCTION
Stratigraphic relations, including two unconformities, are well displayed by the bedrock in the White Plains quadrangle in Westchester County, New York. Fifteen rock units within the traditional "New York City Group" have been mapped in detail there. At the lower unconformity, Cambrian Lowerre Quartzite or Inwood Marble rest on Precambrian Fordham Gneiss and Yonkers Gneiss. Along the upper unconformity, the lower member of the Manhattan Schist rests on various units of the Inwood Marble as well as the Fordham and Yonkers. In addition, a major thrust fault may occur near the base, and locally at the base, of what has traditionally been mapped as Manhattan Schist.
There is widespread evidence for at least four, and probably five, phases of deformation in the region. The Yonkers Gneiss and Fordham Gneiss were folded at least once before the deposition of the Lowerre Quartzite and younger rocks. The pre-Manhattan rocks were deformed, at least mildly, prior to the deposition of the lower part of the Manhattan Schist. A major thrust fault, correlated with Taconic thrusting, may separate member A of the Manhattan Schist from members Band C of the Manhattan Schist. Finally, all of the rocks and previously formed structural features were involved first in major nappe-like isoclinal folds and second in folds with steeply dipping axial surfaces.
The main purpose of this field trip is to illustrate the stratigraphy of the region. In doing so, some of the main structural features will also be shown.

A: BEDROCK GEOLOGY IN THE VICINITY OF WHITE PLAINS, NEW YORK

Inwood Marble
The road log begins at the northbound New York Thruway exit in Ardsley and the route is indicated on Figure 2. The contact between member B and member C of the Inwood Marble is exposed along the west (left) side of the exit ramp. Member C is exposed along the east (right) side of the ramp as well. The Inwood here is in the west limb of a north-plunging syncline with Manhattan Schist in the trough of the syncline underlying the hills on the east and Fordham Gneiss under the hills on the west. Leave the exit ramp and turn right (north) onto route 9A (Saw Mill River Rd.) and then proceed northward along the west limb of the syncline.

Manhattan Schist
Turn right (east) onto Ashford Ave. and proceed southeasterly over the hill, across the synclinal trough. The exposures along the roadsides are Manhattan Schist.

Sprain Brook valley
Ashford Ave. enters Sprain Brook valley which is underlain by Inwood Marble. The ridge ahead to the east is Fordham Gneiss in the center of a north-plunging anticline. There are some small exposures of Lowerre Quartzite along the west limb of the anticline in this vicinity. The gneiss plunges out at the anticlinal nose less than a mile north of here.

West Limb of Anticline
Turn right (south) on Sprain Rd. and proceed southwesterly along the west limb of the anticline. The unpublished field notes of E.C. Eckel (New York State Museum and Science Service, Geological Survey files) report Lowerre Quartzite and Fordham Gneiss behind the houses on the east (left) side of the road but, apparently due to construction, only quartzite float exists there now.

STOP 1. New road cuts on Sprain Brook Parkway Construction site.
The road cuts are along the left (north) side of Jackson Ave. on the approach to the new Jackson Ave. bridge that is now under construction and along the west side of the southbound lane of the Sprain Brook Parkway which is also presently under construction. We will walk north along the southbound lane of the Parkway and be picked up by the bus at Ardsley Rd. Those not wishing to walk may reboard the bus here and ride to Ardsley Rd. Be careful of traffic on Jackson Ave. when disembarking.
Start at the west end of the road cut on the approach to the new Jackson Ave. bridge; in traversing eastward several varieties of rock types in the Fordham Gneiss will be seen in the center of the north plunging anticline. Minor structural features are abundant and many of the linear elements plunge northward apparently parallel to the anticlinal axis. Although this area has not been mapped in detail, it appears that these rocks might be grouped into three mapping units from west to east as follows:
1. Brown to rusty weathered sillimanite-garnet-biotite gneiss and smaller amounts of gray biotite-quartz-feldspar gneisses.
2. Light gray, locally pinkish, biotite-quartz-feldspar gneiss with sparse garnet. This rock looks somewhat like the Yonkers Gneiss in places.
3. Dark gray biotite and/or hornblende gneiss and amphibolite.
It would be necessary to map this area in detail to determine whether or not the above subdivision is meaningful.
After traversing to the west end of the new Jackson Ave. bridge, walk northward along the deep road cuts in subdivision 3, proposed above, and down into the Sprain Brook Valley. Walk north along the west side of the valley to Ardsley Rd. and observe several road cuts in subdivision 3. Drilling data obtained at several places along the Grassy Sprain Valley in conjunction with the highway construction now in progress reveal the predicted presence of Inwood Marble beneath the valley fill.
The contact between dark gray biotite gneiss and light gray to pinkish-gray gneiss is exposed in the road cuts at the west end of the new Ardsley Rd. bridge which is now under construction. This contact projects into the Sprain Brook Valley where it is truncated by the Inwood Marble along an unconformity. The west contact of the light gray or pinkish-gray gneisses has been mapped in detail here and it is truncated by the Inwood Marble approximately three quarters of a mile north of here. Reconnaissance indicates that these gray gneisses are very likely the same as subdivision 2 proposed above.

East Limb of Anticline
Turn left (north) onto Grassy Sprain Rd. and proceed along the east limb of the anticline. The road is near the contact between the Inwood Marble and Manhattan Schist. The hills to the east are underlain by the Manhattan in the trough of a syncline.

Manhattan Schist Member B
Turn left (northwest) onto Ardsley Rd. (A good exposure of member B of the Manhattan Schist is in the road cut along Ardsley Rd. approximately 0.1 mile southeast of this intersection.) Proceed northwest along Ardsley Rd. entering the floor of Grassy Sprain Valley.

Crossing anticline
The bus will stop here in order to allow the group to board and then will continue northwesterly on Ardsley Rd. crossing the anticline.

Recrossing the syncline
Proceed straight through the dangerous intersection where the street name changes from Ardsley Rd. to Ashford Ave. Continue northwesterly on Ashford Ave. re-crossing the syncline.

Have traversed Manhattan, Inwood down into Fordham Gneiss
Proceed through the major intersection and onto the bridge that overpasses the Saw Mill River, New York Thruway, New York Central Railroad tracks, and the Saw Mill River Parkway. In so doing we have traversed from the lower part of the Manhattan Schist through members A, B, and possibly part of C of the Inwood Marble down into the Fordham Gneiss.

Fordham Gneiss Member A
Many exposures of member A of the Fordham Gneiss are present in the hills on the west (left) side of Northfield Ave.

Cyrus Field Rd., named after "the father of the first transatlantic cable".

STOP 2. Harriman Road Reservoir.
Park in the driveway on the right (north) side of the road that leads into the watershed area of the reservoir. We have been allowed to visit this area through the courtesy of the Village of Irvington, Department of Public Works. This is a water supply reservoir, please conduct yourself in accordance.
This is the area of a steeply plunging structural syncline that is defined by the contacts between various members of the Fordham Gneiss (Figure 3). Minor structural features and the orientation of foliation indicates that the syncline plunges 50° to 60° toward the south. It has been possible to map a separate amphibolite within member B of the Fordham Gneiss here (Figure 3) but the amphibolite cannot be separately mapped elsewhere. We will study the syncline by traversing along and across the amphibolite-garnet gneiss contacts (see walking route, Figure 3). Disembark from the bus and proceed southeast along the northeast side of Harriman Rd. to station a.
Station a - Dark amphibolite and biotite-hornblende gneiss along with some garnetiferous gneiss are exposed here on the east limb of the syncline. The contact between the amphibolite and garnet gneiss appears gradational here and it is very difficult to map the amphibolite separately from here south. The apparent gradational nature of this contact may be due to minor folds which are abundant here. Note the pyroxene (green-weathering) rimmed by hornblende (black) indicating retrograde metamorphism. Thin sections of similar rocks in member B of the Fordham reveal amphibole lamellae within the pyroxene and these lamellae are apparently retrograded exsolved pyroxene. The textural and mineralogical relations in this rock are open to various interpretations.
Station b - The exposure of typical gray garnet-rich gneiss in the trees on the north side of the road occupies the keel of the syncline here. Elsewhere in this rock type sillimanite is locally abundant, particularly as inclusions in garnet, but only traces of sillimanite have been observed here.
Station c - Dark amphibolite in steep south-plunging minor folds. Note the trend of the foliation here and then look toward the northeast corner of the reservoir where the amphibolite-garnet is present at station d. The strike obviously changes and this contact outlines a minor fold here on the larger syncline.
Station d - We have progressed northward along the west limb of the syncline and across the garnet gneiss-amphibolite contact. This outcrop of gray garnet gneiss is structurally beneath the amphibolite.
Station e - The garnet gneiss here is in the keel of the syncline. Note the foliation athwart the trend of the amphibolite-garnet gneiss contact. This foliation is apparently parallel to the axial plane of the syncline.
Station f - The amphibolite is in the keel of the syncline here and the foliation is parallel to the amphibolite-garnet gneiss contact. If time permits we will walk along the north shore of the reservoir across many exposures of rocks typical of member C of the Fordham Gneiss.
Station g - This is an exposure of member C of the Fordham Gneiss that here consists of biotite and/or hornblende-quartz-feldspar gneiss, with many quartz-feldspar layers, and amphibolite. These rocks are complexly deformed with many examples of refolded folds as well as boudinaged amphibolite.

Fordham Gneiss-Inwood Marble contact
Proceed north more or less along the Fordham Gneiss-Inwood Marble contact

Sunnyside
Turn left (west) onto the entrance road to Sunnyside (West Sunnyside Lane). Sunnyside is the former country home of Washington Irving who designed and remodeled the house himself and is responsible for its unique architecture.

Inwood Marble Member B
Member B of the Inwood Marble is exposed in the stream on the right (north) side of the road.

STOP 3. Sunnyside.
NO HAMMERING PLEASE!
The contact between the Lowerre Quartzite and member A of the Inwood Marble is exposed here. This same contact is exposed at STOP 2 on Trip H (Ratcliffe, this guidebook).
Sunnyside belongs to Sleepy Hollow Restorations, Incorporated. This is a non-profit organization that has allowed us free access to Sunnyside for purposes of this field trip. Visitors are normally charged an admission fee. Please show your gratitude by being careful.
Proceed through the reception center to the outlet of the pond, "Little Mediterranean". Lowerre is exposed in the brook beneath the bridge and extends upstream. Here, the Lowerre consists of typical tan to buff weathered quartzite, micaceous quartzite, feldspathic quartzite and granulite. More Lowerre is exposed downstream from the bridge and a large fold is clearly displayed at the waterfall. This fold is large enough to be outlined by the Lowerre-Inwood contact on the regional geologic map (Figure 1.). Bedding attitudes indicate that the fold plunges 60° to 65° toward the southeast. A white quartz vein one to two feet thick is present in the axial region of the fold.
The contact of the Lowerre with member A of the Inwood is exposed below the waterfall and the Lowerre is relatively clean quartzite near the top. The Inwood consists of coarse white dolomite marble and a few calcite-bearing beds are also present. A bright green chromium-bearing chlorite is locally present in the coarse white dolomites. Paleontologists have assured me that the siliceous "box work" present here does not represent organic remains.
There is a fine view of the Palisades across the Hudson River. The cliffs are marked by the Palisades Sill which is in contact with the Triassic Stockton Formation at the base of the cliff a little above the surface of the river (Figure 1). An unconformity, somewhere beneath the river, separates the Paleozoic and Precambrian rocks in the vicinity of Sunnyside from the overlying Triassic rocks. This unconformity dips westward and thus projects above the ground surface at Sunnyside. Evidence for the unconformity is clear in the vicinity of Stony Point on the west side of the Hudson River, see Figure 1, Trip H, (Ratcliffe, this guidebook).
There is at least one small exposure of member A of the Inwood on the grounds of Sunnyside. We will not visit the small exposures of member C of the Fordham that are present in the wooded area north of Sunnyside, but the unconformity at the base of the Lowerre must be present somewhere in the vicinity of the northern boundary of the grounds.

Fordham Gneiss Members A and B
Turn left (east) onto Ashford Ave. and proceed east across member A and member B of the Fordham Gneiss.

Fordham Gneiss-Inwood Marble-Manhattan Schist contacts
Start across the bridge that overpasses the Saw Mill River etc. and in so doing, cross the Fordham Gneiss-Inwood Marble-Manhattan Schist contacts.

West limb of syncline
Turn left (north) onto Route 9A (Saw Mill River Rd.) and proceed north along the west limb of a syncline.

Outcrops of Manhattan Schist are on the right (east).

STOP 4. REA Express Terminal.
This is a good exposure of rocks that are typical of member B of the Inwood Marble. It consists of interbedded gray and white dolomite marble; tan, cream colored, and locally pinkish-weathering dolomite marble; tan calc-schist and granulite. There are several north-plunging sinistral folds with half wavelengths of three to four feet outlined by beds in the vicinity of the corner of the cut and the side of the cut parallel to the east side of the building. These are interpreted to be later stage folds and evidence for an earlier stage of Paleozoic folding is revealed locally by folded mineral lineation. There are many other minor folds throughout the exposure. It is noteworthy that the syncline at STOP 2 is very close (Figure 3) and that its orientation is apparently unrelated to the folds present here. This suggests that the syncline at STOP 2 is a structural feature that was developed due to deformation in the Precambrian.
A zone of closely spaced fractures that dip 65° west is present at the corner of the cut. This is probably related to late (Triassic?) minor fault movement.

Inwood Marble Member B
Several exposures of member B of the Inwood Marble are along the right (east) side of the road.

Inwood Marble-Manhattan Schist contact.
Turn right (northeast) onto Route 100B and proceed northeast across the Inwood Marble-Manhattan Schist contact.

Inwood Marble in center of anticline
Turn left (north) onto Route 100A (Knollwood Rd. ). The broad valley to the northeast (right front) is underlain by Inwood Marble in the center of a south plunging anticline. Proceed northward along the west limb of this anticline.

Proceed east across the anticlinal valley.

Manhattan Schist Members A, B, and C
Large road cuts expose members A, B, and C of the Manhattan Schist on the east limb of the anticline.

Manhattan Schist Member C
The extensive road cuts on the left (north) side of the expressway expose member C of the Manhattan Schist in the trough of a south plunging syncline.

Inwood Marble contact with Fordham
The expressway overpasses the Bronx River Valley which is here underlain by Inwood Marble. We cross the Inwood-Fordham contact and proceed down through the upper limb and across the axial surface of an early stage nappe-like fold.

Fordham Gneiss and Yonkers Gneiss
Extensive road cuts expose multiply deformed Fordham Gneiss and Yonkers Gneiss in the core of the early stage fold.

Calcite marble and schist
A road cut on the right (south) side of the expressway exposes interbedded calcite marble and schist at the base of member A of the Manhattan Schist. The contact of these rocks with the Fordham Gneiss is essentially exposed here and is an example of a place where the Middle Ordovician rocks rest directly on Precambrian. We are on the lower limb of the early stage nappe-like fold which has been refolded into an anticline and we are here located on the west limb of this later stage anticline. The lower part of the Manhattan exposed here compares favorably with the fossil bearing beds at Stop 5 and Stop 7 on Trip H (Ratcliffe, this guidebook).

East limb of the later stage anticline.
All of this maneuvering has allowed us to cross the axial plane of the later stage anticline to the east limb but we remain on the lower limb of the early stage nappe-like fold. Proceed northward along the east limb of the later stage anticline.

Proceed along the west limb of the later stage anticline.

STOP 5. Silver Lake.
We are permitted to use this park through the courtesy of the town of Harrison. Please don't litter the area with trash.
An exposure of member A of the Inwood Marble is present near the entrance to Silver Lake Park. Walk northward along the east side of Silver Lake and, in so doing, proceed along the east limb of the northerly plunging later stage anticline and at the same time along the lower limb of the earlier stage nappe-like isoclinal fold. (Figure 4). The steep topography on the west side and at the north end of the lake is underlain by Fordham Gneiss and the ridge on the east by Yonkers and Fordham. We are located on the Paleozoic rocks and the contact at their stratigraphic base projects in the air above our heads so that the stratigraphy is completely inverted here. Walk to the north end of the lake where the hinge of the later stage anticlinal fold is located (Figure 4). Walk northward, up the hill and down the stratigraphic section through the Lowerre Quartzite into the Fordham Gneiss. Note that the bedding in the Lowerre dips northward and thus projects beneath the older Fordham. In walking up the hill we are proceeding across the lower limb of the earlier stage nappe-like fold and essentially along the axial trace of the later stage fold.
The Lowerre here consists of tan to brown weathering gray feldspathic granulite, tan-weathering quartzite and micaceous quartzite, interbedded half-inch to two-inch thick beds of white quartzite and feldspathic granulite. Brown to rusty-weathering feldspathic granulite and feldspathic schist with local sillimanite nodules characterize the basal Lowerre here. The Fordham consists predominantly of gray biotite-quartz-feldspar gneiss.
Minor structural features abound in these rock exposures. Most of the linear elements plunge at 40° to 60° northwestward and apparently are parallel to the plunge of the later stage anticline.

Lowerre Quartzite
There is an exposure of Lowerre Quartzite behind the milk plant on the northwest side of Silver Lake.

Axial surface of nappe-like fold
Proceed north across unexposed Fordham Gneiss and up through the axial surface of the nappe-like fold to the upper limb.

Exposures along either side of the road are Fordham Gneiss.

Kensico Dam
The rock facing on this dam is Yonkers Gneiss that was quarried from the hills to the east of the Kensico Reservoir called "Quarry Heights". Fordham Gneiss is at the east end of the dam, Manhattan Schist is at the west end and the Inwood Marble, though not exposed, is in between.

The New York City Water Supply aerators are on the right.
The aerators are gone, and the site is being used for fill.

Interbedded calcite marble and schist
Interbedded calcite marble and schist at the base of member A of the Manhattan Schist are exposed in the road cut on the right (northwest) side of the road.

STOP 6. United States Post Office in Thornwood.
Member A of the Manhattan Schist is exposed in the cuts alongside and behind the buildings. Characteristic gray and dark-gray sillimanite-garnet muscovite-biotite schist of member A is present here. Before the recent construction and paving, there was an exposure of interbedded white calcite marble and schist here. These rocks compare favorably with the lower portions of the Manhattan Schist that are to be visited on Trip H (Ratcliffe, this guidebook).

STOP 7. Exposures along the east side of Elwood St.
The exposures of member A of the Manhattan Schist behind the buildings as well as on the wooded slope consist of the typical fissile schist and some gray and white calcite marble beds. Definite interbedding of marble and schist cannot be proven here although there are at least two exposures that strongly suggest such a relationship.

STOP 8. Member E of the Inwood Marble.
Park beyond the United States Post Office at the end of the street. Walk south over the hill toward the Taconic State Parkway. An exposure of member E of the Inwood is on the west side of the hill along the east edge of the Taconic State Parkway. The contact between gray-weathering calcite marble (member D?) and tan-weathering calcite marble, typical of member E, outline a tight isoclinal fold.

Inwood Marble Member D
The large roadcut on the south side of the intersection is in member D of the Inwood and there are exposures of member E up on the hill south of the road cut. Proceed southward on Route 9A along the west limb of a syncline with Fordham Gneiss underlying the hills on the west and Manhattan Schist those on the east.

STOP 9. Member E of the Inwood Marble.
These exposures are typical of member E of the Inwood Marble and consist predominantly of tan and gray-weathering calcite marbles. Note the many northeast plunging folds.

Proceed southward continuing in the Inwood Marble.

Unconformity at the base of the Lowerre Quartzite
There is an excellent exposure of the unconformity at the base of the Lowerre Quartzite in a cut behind the A & P warehouses west of Route 9A. There are extensive exposures of Lowerre on the hillside extending all the way across the Saw Mill River Parkway to the west. Continue southward through Elmsford more or less along the Inwood-Manhattan contact.

STOP 10. Warburg Campus.
Park in the parking lot north of Woodlands High School. This 160 acre campus is a former estate of Felix Warburg that was given to the town of Greenburgh for educational purposes. The classroom buildings on the campus accommodate 3000 students from kindergarten through high school. We have been granted permission to visit this area by the administration of Greenburgh School District No.8.
The rocks here are at the nose of a southwest-plunging later-stage anticline (Figure 5). Evidence for two, and possibly three, phases of deformation is displayed by minor structural features. The contacts between amphibolite (member B of the Manhattan) and schist, schistose gneiss and granulite that are typical of member C of the Manhattan outline the fold (Figure 5). Note that member B is above the base of member C here.
Some areas of particular interest are indicated on the map (Figure 5) by lower case letters. The upper and lower contacts of the amphibolite are easily identified in the vicinity of point "a" where gray to brownish-weathering feldspathic garnet-muscovite-biotite schistose gneiss, gneiss and granulite with local white sillimanite nodules is below as well as above the amphibolite. Trace the contacts south-eastward by walking across the valley to exposures on the steep slope west of the classroom building in the vicinity of point "b" on Figure 5. The lower amphibolite contact is folded here and though there are several examples of the results of multiple deformation, a particularly fine example of a refolded fold is present near the north end of these exposures. Evidence for three stages of deformation is found here where the slip cleavage that deforms an earlier foliation appears to be folded.
Proceed southeast over the top of the hill where amphibolite is well exposed. An unusual occurrence of magnetite with white quartzfeldspar rims is present in the amphibolite on the southeast side of the hill. Many interesting minor structural features are present in the rocks on the hill in the vicinity of "c" (figure 5). Toward the north between the gym and the classroom building is an exposure of schist with particularly good examples of sillimanite nodules.

Inwood Marble Member B
Road cuts here expose member B of the Inwood Marble and a particularly good exposure of member B is present on the east (left) side of Route 9A between the Thruway overpass and the southbound Thruway entrance.

Manhattan C on the left (east).

Manhattan C on both sides of the highway.

Road cuts in the Fordham Gneiss.

Yonkers Gneiss on the left (East).

Fordham Gneiss is on the right (west).

Fordham Gneiss is on both sides of the highway.

Yonkers Gneiss
Yonkers Gneiss is exposed in the old quarry on the right (west) and there are active quarries in the Yonkers a little further west. This is in the area specified by Merrill (1890, p. 388) as typifying the Yonkers Gneiss.

Yonkers Gneiss
Yonkers Gneiss is exposed in a cut along the Thruway exit ramp on the left (east).

Highview Reservoir is on the left (east).

STOP 11. Type locality of the Lowerre Quartzite.
This is the type locality of the Lowerre Quartzite designated by Merrill (1896, p. 26). The portion of the Lowerre now exposed here is predominantly well bedded gray and tan-weathering feldspathic granulite and gray feldspathic muscovite-biotite schist that weathers tan to brown. Typical tan-weathering quartzite is present about forty to fifty feet above the base but is subordinate. It seems likely that more of the characteristic quartzite was exposed here when Merrill originally defined the Lowerre but that it has since been removed through the work of man. It also appears that Merrill used the modifier "quartzite" in the name Lowerre Quartzite because the most distinct rock types that characterize the assemblage of rocks in this formation are tan weathering quartzite and feldspathic quartzite.
The Fordham Gneiss beneath the Lowerre consists mainly of amphibolite with some gray garnet-biotite-gneiss. This is another place, similar to STOP 5, where the base of the Lowerre is "dirty". There are other places, such as the cut behind the A & P warehouses at mileage 36.3 (this field trip), where clean quartzite and feldspathic quartzite are directly in contact with Fordham.
The unconformity here is deformed into a series of northeast plunging sinistral folds. This is in accord with the map pattern in this vicinity (Merrill and others, 1902) which indicates the rocks here are on the west limb of a stratigraphic syncline.

B: CRETACEOUS DELTAS IN THE NORTHERN NEW JERSEY COASTAL PLAIN
By James P. Owens, James P. Minard, and Norman F. Sohl.
U. S. Geological Survey, Washington, D. C. 20242
(Publication authorized by the Director, U. S. Geological Survey.)
INTRODUCTION
In recent years there has been a growing recognition of the importance of deltaic deposits in many sedimentary basins. The extensive investigation of modern deltas has resulted in the isolation and description of many of the subenvironments of this very complex sedimentation system. On this field trip, some of the subenvironments of an ancient deltaic system will be examined.

B: CRETACEOUS DELTAS IN THE NORTHERN NEW JERSEY COASTAL PLAIN

STOP 1. Woodbridge clay of the Raritan Formation (Figure 8).
Section as follows:
5-10 feet of sand and gravel of the Pensauken Formation.
30-40 feet of interbedded sand and clay of the Woodbridge unit of the Raritan Formation. Numerous layers of siderite and iron oxide-cemented sand are present. Some sand layers contain marine fossils. Interpreted as prodelta-bottomset beds.
5-6 feet of sand and clay containing much wood. Some wood appears to be in an upright position. Probable marsh deposits.
20 feet of dark-gray clay which is weathered at the top. Possible lagoonal origin.

STOP 2. Sayreville Sand Member of the Raritan Formation (Figure 9).
Section as follows:
20-40 feet of cross-stratified sand exposed in the pit walls. Interpreted as channel-fill and spit facies.

STOP 3. Laminated beds of sand and clay of the Morgan beds
Laminated beds of sand and clay of the Morgan beds (Berry, 1906) in the lower part of the Magothy Formation (Figure 10). Section as follows:
15-25 feet of alternating beds of yellow-brown to light-gray micaceous quartz sand and clay. A considerable amount of carbonaceous matter is present throughout. Interpreted as natural levee deposits.

STOP 4. Magothy Formation
Magothy Formation overlain by several feet of Merchantville Formation and Pleistocene sand and gravel (Figure 11). Section as follows:
5-6 feet of Pleistocene silt, sand, and gravel.
5-6 feet of dark-greenish-black quartz-glauconite sand of the Merchantville Formation. Interpreted as prodelta to open shelf deposits.
8 feet of dark-gray clay with some sand partings.
12 feet of alternating dark-gray to black clay and light-gray quartz sand layers. Layers are about 1/4 to 1/2 inch thick. Pyrite nodules are present throughout.
12 feet of white to light-gray quartz sand with some lignite and clay layers. The above 32 feet of the Magothy is interpreted as top set and foreset beds.
1 foot of gray-black clay with light-gray quartz sand and siderite concretions (exposed at low tide). Fossils are present in the siderite. Interpreted as prodelta and bottomset beds.

STOP 5. Merchantville Formation
Merchantville Formation overlain by several feet of Pleistocene sand and gravel and spoil from the Woodbury Clay (Figure 12). Section as follows:
5-10 feet or more of Pleistocene sand and gravel and disturbed Woodbury Clay. Apparently was disturbed and intermixed during excavation or subsequent pushing aside.
20 feet, plus or minus, of dark-greenish and grayish-black sandy silt and clay and sandy clay of the Merchantville Formation. Contains abundant mica, glauconite, and layers of siderite. Interpreted as prodelta and bottomset deposits.
Several feet of the upper, weathered sand and clay layers of the Magothy can be seen near the entrance of the pit.

STOP 6. Upper Navesink Formation
Upper Navesink Formation overlain by lower part of the Red Bank Formation (Figure 13). Section as follows: 25 feet of the lower part of the Red Bank Formation (Sandy Hook Member). Mostly fine-to medium-grained quartz sand with considerable feldspar, much mica (green and colorless), and some glauconite, particularly in the base. The upper part of the section is weathered to brown, the lower part is dark-gray. Micro-fossils and small megafossils and shell fragments are abundant in the dark basal part, and this unit is more clayey and compact.
15 feet of greenish-black, clayey, glauconite sand of the Navesink Formation. Several shell beds are present. Exogyra, Pycnodonte, Ostrea, Choristothyris, and Belemnitella are common. (The total thickness of the Navesink is about 25 feet here).
These sediments are interpreted as open shelf marine deposits beyond the laminated prodelta beds. Except for the shell beds there is a lack of conspicuous bedding. The abundance of glauconite is suggestive of deeper water and more uniform sedimentation.

C: THE TRIASSIC ROCKS OF THE NORTHERN NEWARK BASIN
By E. Lynn Savage, Brooklyn College of The City University of New York
INTRODUCTION
Objectives of the Field Trip.
Outcrops to be visited on this trip have been selected to illustrate some of the problems involved in the interpretation of Triassic rock units and facies in the northern Newark Basin. (Figure 1). Where possible emphasis is directed toward general Triassic problems, as well as to those which are unique to the northernmost area of this basin.
Although it is generally accepted that much of the Triassic has been removed by erosion, there are two contrasting ideas as to whether the present northeastern end of the Newark Basin marks the former extent of the sediments:
(1) The present outcrop area is almost the same as the original extent (McLaughlin, 1957, p. 1498; Glaeser, 1966, p. 101).
(2) The sediments were once much more extensive, covering the area between the New Jersey-New York Trough and the Connecticut Trough (Sanders, 1963, 1960; MacLachlan, 1957, p. 13; Wheeler, 1938).

C: THE TRIASSIC ROCKS OF THE NORTHERN NEWARK BASIN

Southwest end of fault
Tunnel plaza and portal to north (left) are at southwest end of fault (Figure 12 A, B) cutting diagonally across Palisade Sill. Downdropped block is on east (right) side. There are many such faults along the Palisades.

Jointed diabase on left.

Regional erosion surface levels top of sill
Small park on right (east) commemorates duel between Aaron Burr and Alexander Hamilton. Regional erosion surface levels top of sill (Figure 13).

Olivine zone in Palisade Sill on left (see Figure 15A).

Stockton arkose on left
Metamorphosed rather well-sorted yellowish-gray to very pale orange Stockton arkose and overlying chilled border of sill on left.
Coarse-grained arkose at contact, locally cross-bedded with dispersal to S or SW, contains abundant plagioclase and orthoclase, some quartz, pale green diopside and vermiculite,. and minor sphene and talc. Fine-grained arkose within 12 inches of the contact consists mainly of albite, with minor vermiculite and talc, and a trace of chlorite.

Stockton arkose on left.

Large columnar joints with smaller joints in lower part of sill. Talus.

Stockton arkose and cliff of sill
Stockton arkose and cliff of sill on left (just south of Lever Brothers Research Center). Bedded, coarse to very coarse-grained arkose with 2-foot unit of tabular cross-bedding with dispersal to SW.

Well-bedded, very dark, fine-grained Lockatong hornfels.

STOP 1 Gorge and River Roads. Lockatong Hornfels
Gorge and River Roads. Lockatong Hornfels. Time here: 30 minutes. Park in lot of Celatex Corp. (Allied Chemical).
A composite section of Lockatong hornfels and interbedded stockton arkose is exposed in the excavation (watch for falling rock) on River Road (Figure 14A) opposite the Mobile Service Center and in the roadcut on the west side of Gorge Road (Figure 14B). This sequence (strike N 40° E, dip 15° W) consists of (1) about 18 feet of dark gray, well-bedded Lockatong hornfels in 3 well-developed cycles, overlain by (2) about 15 feet of bedded, rather well-sorted yellowish-gray Stockton arkose, which is in turn overlain by (3) about 50 feet of dark gray, well-bedded Lockatong hornfels below the Palisade Sill.
1. The asymmetrical cycles in the excavation are analcine-bearing "chemical" cycles like those found in western New Jersey and adjacent Pennsylvania (Van Houten, 1964, 1965). Because of their unique composition, these deposits were easily altered by isochemical thermal metamorphism. In contrast, the arkose 50 feet below the sill is virtually unaltered. In pattern, each cycle (Figure 14C) originally consisted of a lower very dark gray to black shaly to platy carbonate-rich feldspathic mudstone (converted to a biotite-albite hornfels) with thin laminae and local beds (1 to 3 cm) of calcite and dolomite, a middle platy carbonate-rich portion with abundant disruption by shrinkage, converted to a calc-silicate hornfels, and an upper massive analcine-rich argillite, now commonly with a splotched fabric produced by metamorphism to a biotite-albite-analacine hornfels.
2. The slightly metamorphosed arkose 50 feet below the sill consists mainly of plagioclase, orthoclase and quartz, some vermiculite, and a trace of talc.
3. Spotted Lockatong hornfels of a tetrital cycle within 5 feet of the sill consists mainly of biotite and plagioclase, some orthoclase and andalusite, and a trace of chlorite and magnetite. Lockatong hornfels 15 to 20 feet below the sill contains minor analcime.
The following additional accessory minerals have been found in this hornfels facies (Lewis, 1908, p. 136-147): pale green augite, apatite, cordierite, epidote, hornblende, sillimanite, scapolite, dark-green spinel, sphere, tourmaline, and vesuvianite.
The variations in mineral assemblages found here and in the Granton Quarry (STOP 8) resulted largely from differences in composition and amount of water present, and not from major differences in temperature and pressure.

Large xenolith of Lockatong hornfels
Large xenolith (15 feet by 30 feet) of Lockatong hornfels about 15 to 20 feet above base of sill, exposed behind Virginia Lee Lace Co. Baking produced coarse-grained biotite-plagioclase hornfels with chlorite, pale green and colorless pyroxenes, and more coarsely crystalline stringers of chlorite, biotite, calcite, diopside, albite and very pale green muscovite.

Sill exposed on left (west), hornfels in cut to east (right).

Lockatong hornfels below sill behind Edgewater Welding Co.

Stockton arkose and Lockatong hornfels
Stockton arkose and Lockatong hornfels behind Edgewater sewage treatment plant.

STOP 2. Palisade Sill and Lockatong Hornfels
Palisade Sill and Lockatong Hornfels along abandoned trolley route. Time here: 1 hour. Park on east side of Undercliff Avenue, opposite small park with 3 benches.
Traverse through Palisade tholeiitic diabase sill (Figure 15 A, B, C) - up (southwest) an abandoned trolley route along a brook, behind houses:
Lockatong Hornfels below sill, as at STOP 1.
Irregular cross-cutting contact (Figure 16A).
Xenolith 2 feet thick, 15 feet above base of sill; unusually coarse-grained biotite-plagioclase hornfels.
Olivine diabase, generally about 15 feet thick, 50 feet above the base at switch-back on trolley route. Dr. S. Bhattacharji will discuss its origin.
Normal diabase throughout the middle of the sill.
Upper coarse diabase with pegmatitic schlieren.
Upper chilled border.
Hypotheses proposed to explain differentiation of the diabase sill and to account for the layer of olivine diabase are:
1. Gravitational settling of early-formed olivine and later pyroxene crystals (F. Walker, 1940). Although widely cited as such, the Palisade Sill probably is not a good example of gravitational differentiation. -
2. Fractional crystallization (Figure VH 2, C) by ionic diffusion and convection circulation of magma, supplemented by minor gravitational settling of large olivine crystals (Hess, 1956, p. 1960).
3. Fractional crystallization, with late-stage injection of a new pulse of magma into the partially crystallized mush. Large olivine crystals concentrated by gravitational settling (K.R. Walker, 1962; 1967 in press).
4. Mechanical or hydrodynamic flow differentiation, with central concentration of early-formed olivine crystals during intrusion of the magma. Crystal mush then settled as a result of fluctuation of velocity and pressure (S. Bhattacharji, 1967).

Olivine zone halfway up cliff on left.

Olivine zone is at road level.

Outcrop of sill on right.

Phytosaur was found below the bridge
A phytosaur, Clepsysaurus (Rutiodon) was found in the stockton arkose below the bridge.

Outcrops of sill on both sides of road.

Outcrop of sill.

Outcrop of sill on left.

Outcrop of sill on right. Lipton Company on left.

Glacially polished diabase on right.

Jointed diabase on both sides of road.

Glaciated diabase on right

Stocton arkose, dikes
Along Hudson River at Sneden's Landing approximately 45 feet of light gray thick-bedded and locally cross-bedded Stockton arkose is interbedded with reddish-brown to pale lavender baked mudstone. Dispersal was to the northwest (Figure 11). Locally dikes of arkose have been injected into the mudstone. The arkose contains angular pebbles of quartz and pink feldspar as much as an inch in diameter; in contrast to sandstone found north of Piermont (and higher in the stratigraphic sequence) zircon, rutile and authigenic anatase are abundant, tourmaline and garnet are rare, and metamorphic rock fragments are absent (Savage, 1967).

Outcrops of diabase at entrance to Tallman's State Park. Olivine zone.

Sparkill Gap.
Sparkill (formerly Overpeck) Creek in the gorge is the only stream that flows eastward across the Palisade Sill into the Hudson River. Presumably it flows along a cross-fault (such as seen at Lincoln Tunnel plaza) that has offset the sill more than 900 feet westward on the north side.
According to Johnson (1931) the Hudson River originally flowed southwestward on the Schooley erosion surface above the position of the sill, was superposed on it and cut a water gap (Figure 17). Later a subsequent stream flowing on relatively non-resistant rocks east of the sill captured the ancient Hudson drainage by headward erosion. Overpeck Creek then reversed the original drainage direction. This explanation does not account for the coincidence of the gap and a cross-fault (see Thornbury, 1954, p. 234-240, for discussion of the problem).
Between Piermont and Nyack Beach State Park (STOP 3), there are many outcrops and abandoned quarries of "brownstone" which was used extensively for building-stone more than 50 years ago. Most of the rock is a dark brown to reddish brown well-sorted medium to fine-grained arkose, commonly interbedded with reddish brown mudstone. Some of the lighter colored arkose is coarser grained, but conglomerate is rare. Presumably these deposits are a gradational sequence between the uppermost part of the Stockton Formation and the lower part of the Brunswick Formation, and differ in heavy mineral content, sedimentary-metamorphic rock content and dispersal direction from those in the upper part of the Stockton Formation to the south (Savage, 1967, p. 34).

Glacial till overlying diabase on right.

More till on diabase on right.

Outcrop of diabase on left.

View of south end of Verdreitege Hook
View of south end of Verdreitege Hook (Hook Mountain) portion of Palisade Sill above Nyack Beach state Park.

Large glacial erratic on right, on lawn of library built of "fieldstone. "

South end of Verdreitege Hook with spectacular talus slope.
5 minute stop for photographs.
North of Nyack the Palisades are as much as a mile west of the Hudson River because the sill intruded a higher part of the west-dipping Newark sequence. Then it swings back to the river at Nyack Beach state Park, cutting across somewhat lower Newark strata (Figure 3). At its north end the intrusion is a dike that intrudes successively higher Brunswick beds (Figure 2) and turns sharply to the west almost perpendicular to strike; at its western end it completes a sickle-shaped arc. Diamond-drilling in a quarry at Little Tor near Haverstraw shows that the intrusion dips about 45° SW (Lowe, 1959).
A distinct olivine-rich zone is absent at the northern end of the Palisade intrusion as it is at its southwestern end in west-central New Jersey. Nyack Beach state Park.

STOP 3. Lower Brunswick deposits.
Nyack Beach state Park. Lower Brunswick deposits. Time here: 1 hr. 45 min.
LUNCH will be served after a 1 and 1/3 mile walk to outcrops in the lower part of the Brunswick Formation.
The Park authorities have made this convenient stop available to us. Do not disturb the foliage or the crops. Please collect specimens only in those areas where there has been recent blasting of ledges. Watch out for copperhead snakes, yellow-jacket wasps, poison ivy and poison sumac.
Traverse along footpath leading north from north end of parking area.
Distances noted below were measured from beginning of the path.
200': 15 to 20 feet of yellowish-gray arkose crop out 40 inches above the path.
895-950': Picnic tables; old quarry in reddish-brown mudstone and yellowish-gray arkose.
1450-1570' : Outcrop exhibiting rapid facies changes, especially at north and south ends:
7': Massive reddish-brown mudstone; cross-bedded; marked channelling. 8': Reddish-brown shale.
13' : Micaceous reddish-brown siltstone and shale; cross-bedded. Scattered pebbles of quartzite and quartz, and pieces of shales.
8': Reddish-brown shale.
2' 0 Massive reddish-brown mudstone. Path level
2215-3745': More talus; columnar joints in diabase. Note sinuous joint surfaces. Pass fireplaces.
3745-3925': Tree-clad slope.
4040-4405': Outcrop near open stone shelter:
10': Massive light gray arkose, locally cross-bedded.
2': Reddish-brown mudstone.
4': Thin-bedded, pale reddish-brown arkose, interbedded brown mudstone.
8': Massive, tough light-gray arkose, rare cross-bedding and coarse layers with pebbles of angular quartz as much as 2 1/2 inches in diameter, pieces of feldspar as much as 1 inch long and intraformational mudstone clasts.
Path level.
Continue along winding path. Diabase above is conspicuously jointed. Sing-Sing prison across river to east.
5571-6039': At south end diabase is at path level. Rises to north to reveal contact with arkose which has not been metamorphosed more than a few feet from the sill. Beware of yellow jacket nests in brush near this contact.
6039-6080': Cover beyond retaining wall 10 feet of cross-bedded light-gray arkose overlies reddish-brown mudstone.
6445-6465': Arkose with rare gray limestone and quartz clasts to 1 inch in diameter; pink feldspar to 2 inches in diameter, and rare pebbles of pegmatite.
6570': Arkose in large block is cross-bedded, contains clasts of quartz, red sandstone, pink feldspar, shale, mica schist, and relatively abundant almandine garnet.
6575': Excellent outcrop extends northward for about 1000 feet. Exhibits rapid facies changes and variety of sedimentary features characteristic of fluvial sedimentation (Figure 18A). N62W, 13° W.
5': Yellowish-gray arkose with large scale channeling and cross-bedding.
6': Interbedded yellowish-gray arkose and reddish-brown mudstone. Unit pinches out to north.
11': Reddish-brown to lavender mudstone with irregular upper contact. Cross-bedding, with scour and fill, burrowing, mudcracks, and ripple marks (2 inch crests, N68W), as well as load and flute casts. Interbedded with layers of medium to coarse-grained micaceous reddish-brown arkose grading (Figure 18A) into lensing buff and lavender arkose with pebbles of limestone and feldspar. The lower part of the mudstone also contains pebbles of quartzite, quartz and feldspar. About 5 feet above the base at the south end of the outcrop a greenish-gray layer consists largely of rounded grains of silty mudstone. Some may be Paleozoic lithic grains, but many with concentric structure, elongate shape and calcite cores apparently are intraformational mud pellets.
6580': Very coarse arkose with angular quartz as much as 1 inch in diameter, pieces of shale parallel to bedding, and clasts of limestone and feldspar, interfingers with reddish-brown mudstone.
6665': Well-developed tabular cross-bedding, rare in Newark rocks in Rockland County.
6755': Upper contact of lower reddish-brown mudstone unit is about 5 feet above the path.
6755-6770': Arkose scoured by channels. Reddish-brown mudstone dikes at north end probably was injected during burial (Figure 18B).
6775':
5': Massive yellowish-gray arkose.
5': Interbedded reddish-brown mudstone and tan arkose.
11': Reddish-brown mudstone.
Northward the top of the extensively burrowed lower unit is 8 feet above the path and is overlain by mottled arkose 11 feet thick which in turn is overlain by 4 feet of yellowish-gray arkose with large scale cross-bedding (Figure 19A).
6930': Slumped mudstone 3 feet above path.
6980-7015': Six inch layers of reddish-brown mudstone interbedded with reddish-brown silty sandstone a few inches thick with marked cross-bedding and scour and fill (Figure 19B).
7185': Well-developed cross-bedding in yellowish-gray arkose. Return to Park. LUNCH will be served at tables south of the parking area. Time here: 30 minutes.

Metamorphosed arkose and mudstone
Thermally metamorphosed yellowish-gray arkose and reddish-brown mudstone (as seen at STOP 3) in excavation on left.

Beginning of roadcut through Verdreitege Hook
Beginning of roadcut through Verdreitege Hook to inner side of the "sickle" (Figure 1).

Fault controlled gaps?
Gaps to east (right) and northeast (ahead) across Palisades may be controlled by faults (Thompson, 1959) or are former superposed stream valleys (Kummel, 1898, p.24).

Erratics on shore of Rockland Lake.

Gneiss and diabase erratics in till on right.
Some are more than 6 feet long.

Excavation in till.

Polygonal jointing
Unusually well-developed polygonal jointing in diabase at right, and in New York Trap Rock Quarry at Little Tor above road to left. North side of "sickle."

Talus slope up hill on left.

Arkose above tough reddish-brown mudstone on left,
Arkose above tough reddish-brown mudstone on left, on northern and outer side of the "sickle. "

Talus with very steep angle of repose.

Scarp has receded to the west.

North rim of High Tor
Road follows the north rim of High Tor and progressively crosses younger strata to the west.

Ramapo Mountains visible to the west.

Glacial erratics common.

Deposit of meltwater delta (?) on right
Deposit of meltwater delta (?) on right; in lowland between sill (left) and Ramapo Mountains (right).

Sand and Gravel quarry
Mt. Ivy Sand and Gravel Company quarry in Mt. Ivy meltwater delta dispersed to the south or southwest. About 5 feet of steeply dipping, light tan fore set beds above 8 to 10 feet of horizontal dark brown and reddish-brown to dark gray beds, and overlain by very poorly-sorted glacial (?) deposits.

Ramapo Mountains rise to west.

Outcrop of Ladentown diabase.
The Ladentown diabase extends for about 2 miles along the road, forming a series of low hills. It is crossed by several streams and is locally covered by glacial drift. The rock varies from fine-grained diabase to medium-grained vesicular basalt with intersertal texture, and structures like pahoehoe have been reported.
This igneous mass may connect with the Palisade diabase across the 2-mile drift-covered stretch to Mt. Ivy (Kummel, 1898, p. 41). The flow-like features of the Ladentown sheet and its position high in the stratigraphic sequence suggest that here the northwest end of the Palisade intrusion may have reached the surface.

Steep hill of diabase on left (east).

Closely-spaced, curved joints in diabase
Closely-spaced, curved joints in diabase on left differ markedly from the large-scale vertical jointing in the sill along the Hudson River.

East-dipping poorly-sorted conglomerate
East-dipping poorly-sorted conglomerate with clasts of Paleozoic rocks. In lower part some clasts are 1 to 2 feet in diameter.

Limestone conglomerate underlying hill.

Hill steepens on left. Ladentown diabase.

Hill of Ladentown diabase
Hill of Ladentown diabase and outcrop at road level on left (north). Fine-grained vesicular diabase with intersertal texture, but without flow texture in specimen examined. Interstices filled with very dark devitrified glass; scattered patches of iddingsite, amygdules of wordenite with a slender vein of quartz in some.

Abandoned quarries in limestone conglomerate
One of several abandoned quarries in limestone conglomerate on farm on southeast corner of intersection. Exposure of conglomerate on glaciated surface between old barn and house, just west of the private driveway.

STOP 4. Border Conglomerate in Upper Brunswick Formation.
Time here: 20 minutes.
This spectacular border conglomerate consists of rounded clasts as much as 4 feet in diameter in gravelly reddish-brown sandstone. Most of the clasts are gray cherty limestone, formerly quarried for burnt lime. Clasts of quartzite and sandstone are also present. The conglomerate is remarkably closely packed with little matrix. Conglomerate in this area east of the Ladentown diabase dips about 5° west (Klimmel, 1898, p. 40). See Figure 20 A, B.
This fanglomerate facies occurs at several places along the western boundary of the Triassic basin and is well-known as the "Potomac Marble" from Point of Rocks, Maryland.

Drive along the fault zone at the western border of the Triassic basin.
Ramapo Mountains to the west. The road parallels the Mahwah River which flows along the fault zone at the western border of the Triassic basin.

STOP 5. Border Conglomerate in uppermost Brunswick Formation.
Time here: 30 minutes.
The section exposed along the west side consists of about 10 feet of boulder conglomerate interbedded with, and overlain by reddish-brown gravelly sandstone. The clasts consist largely of a variety of Paleozoic limestones, together with red sandstone and Green Pond (Silurian) conglomerate and quartzite.
On the east side of US 202 the deposits are less coarse, and exhibit well-developed cross-bedding with dispersal direction to the south. The regional dip of the sequence is to the southeast, toward the Ladentown diabase (Figure 20 A, B).
A 12-foot limestone boulder has been reported just south of here.

Gneiss of Ramapo Mountains exposed on right

Exposure of slickensides in the Ramapo Fault zone.
Present relief between Precambrian crystalline rocks and Triassic sedimentary rocks is due to differential erosion. Top of hill on gneiss; quarry in diabase of Union Hill seen to the southeast.
At Union Hill, the trap is associated with dark purplish-red cobble conglomerate which contains clasts of quartzite, reddish-brown, greenish-gray and gray limestone, and amygduloidal basalt. The largest clasts present are as much as 1 foot in diameter and one 3 feet in diameter has been reported. About 30 percent of the clasts here are limestone.

Glacial erratics on right.

Glacial drift on right.

STOP 6. East end of Cherry Hill - NY 59. Brunswick Formation.
Time here: 30 minutes.
The Clarkstown Police will conduct our group across the highway to the best outcrops on the north side of the road.
This section in the lower part of the Brunswick Formation is about 0.2 miles long and consists of about 125 feet of strata (N30E, 6°W) composed of interbedded buff to reddish-brown feldspar-rich sandstone and reddish-brown mudstone. Many of the layers have well-developed crossbedding (Figure 21) commonly in the 1 to 2-foot sets; one cross-bedded unit is 11 feet thick. Dispersal direction generally is to the southeast, although some cross-beds dip westward (Figure 11). Unbedded mudstone and fine-grained sandstone apparently were mottled by burrowers.
The feldspar-rich sandstones here, as in much of the Stockton Formation, contain relatively abundant sodic plagioclase.
The traverse proceeds from east to west along the outcrop:
Top of Sequence (west end).
50'+: Reddish-brown mudstone, variably silty and fissile, with local sandy layers, On south side of road, at about this level, a 1-foot pebbly layer contains quartz clasts as much as 1/2 inch in diameter.
20': Reddish-brown sandstone interbedded with mudstone that is variably fissile. Base is marked by scour and fill, or flutes, and the basal bed contains intraformational mud chips. Lowest sandstone unit is conspicuously parallel-bedded, with convolutions overturned to the east. Local ripple-marks have crests trending N27°E. Scour and fill is common throughout the sequence.
Mudstone in the lower part of the unit contains a thin layer of drab mudstone with calcareous pellets. An ll-foot silty mudstone with thin layers of sandstone in the middle unit is conspicuously crossbedded.
15': Reddish-brown, cross-bedded mudstone, commonly weathers into slivers and chips. Drab calcareous nodules in upper part.
4': Reddish-brown sandstone with very thin mudstone interbeds, and a 3-inch layer of mudstone in the middle. Round mudstone clasts on some bedding planes; scattered quartz pebbles, locally in small lenses.
2.5': Reddish-brown fissile mudstone, with interbedded sandstone
10.5': Reddish-brown feldspathic sandstone. Commonly medium-grained with rare pebbles and locally cross-bedded.
5': Reddish-brown fissile mudstone.
East end of Outcrop.

STOP 7. Conglomerate in lower Brunswick Formation
Low ridge on lawn 157 Sickletown Road (Wright's property) consists of reddish-brown quartz pebble conglomerate and sandstone, locally crossbedded. Clasts are principally rounded quartz as much as 1 inch in diameter, a few pebbles are as much as 4 inches in diameter. This conglomerate, about 1/2 mile from STOP 6, emphasizes the lateral variation in Triassic deposits in Rockland County.

Outcrop of Palisade Sill on left.

Hill of cross-bedded calcareous arkose on right (west).
This sandstone with an interbedded 2-3 inch limestone unit (Kindle, 1944, p.4) overlies the Lockatong strata exposed in the Granton Quarry 1/2 mile to the south (see Figure 15A).

STOP 8. Lockatong Hornfels and subsidiary sill.
Enter driveway at south end of Diana Stores property. Drive to rear, turn right and drive to north end of property and south face of escarpment (see Colbert, 1966, Figures 1,2).
About 60 feet of Lockatong hornfels lies between the top of the Palisade Sill to the east and a subsidiary sill at Granton Quarry, North Bergen (Figures 15A, 16B, 22). The excellent exposure at the north end of the Diana Stores parking area consists of five complete hornfelsed "detrital" cycles (Van Houten, 1964), two of which are exposed along the east wall of the lower quarry. In contrast to the "chemical" cycles in the River Road excavation (STOP 1) each of these is thicker, shows extensive evidence of burrowing as well as shrinkage cracking, and contains cross-bedded siltstone and very fine-grained arkose pervaded by diopside in the upper part. The presence of prehnite and recrystallized feldspathized arkose in the middle and upper part of each cycle suggest metamorphism in presence of water vapor.
The overlying subsidiary sill, more than 20 feet thick, has been reported to contain an arkose xenolith a maximum of 10 feet thick and 100 feet long (Lewis, 1908, p. 135).
In spite of the extensive hornfelsing of the Lockatong rocks they still yield fossils of reptiles, fish, estheriids and plants (Colbert, 1965, 1966).

D: EXCURSION TO THE STERLING AND FRANKLIN AREA IN THE HIGHLANDS OF NEW JERSEY
By Eugene A. Alexandrov
Queens College of The City University of New York
GEOLOGY ALONG THE ROAD BETWEEN LONG ISLAND AND THE HIGHLANDS OF NEW JERSEY
The Geological trip to the Highlands of New Jersey starts at Queens College in Flushing and crosses the western part of Long Island in Queens County, the East River, Manhattan, the Hudson River, the Palisades, and the Lowlands of New Jersey.

D: EXCURSION TO THE STERLING AND FRANKLIN AREA IN THE HIGHLANDS OF NEW JERSEY

Crossing the Ronkonkomo terminal moraine.

Outwash Deposits
Grounds of the 1964-1965 New York World's Fair. Science Museum. The outwash deposits of Wisconsin age underlie the area between the terminal moraine and the East River.

Midtown Tunnel
Entrance to the Midtown Tunnel under the East River. The tunnel crosses ridges formed by Fordham Gneiss and Manhattan Schist, and depressions between the ridges eroded in Inwood Marble. The depressions are filled with Recent overburden.

Crossing Manhattan Schist
Crossing Manhattan along 34th St. , the underlying formations are mainly Manhattan Schist.

Entrance to Lincoln Tunnel
Entrance to Lincoln Tunnel under the Hudson River excavated in Recent sediments.

Western part of the tunnel crosses Upper Triassic continental seds
Boundary between the States of New York and New Jersey. The western part of the tunnel crosses the Upper Triassic continental sedimentary sequence underlying the diabase sill.

Crossing the escarpment of the diabase sill.

Fault in the diabase sill
Fault in the diabase sill (a narrow valley developed along this fault north of the road).

Leaving the diabase sill.
Leaving the diabase sill. The area is underlain by Upper Triassic shales, sandstones, and argillites. Turn northwest on Route 3 crossing the Hackensack Meadows.

Land rises because of harder sandstone
The land rises at the entrance to Rutherford because of the appearance of harder sandstones.

First Watchung Mountains formed by Triassic lava.

Lava with columnar jointing on the left side of the road.

Pillow lava structure on the left side of the road.

Triassic lava of the Second Watchung Mountains.

Triassic lava of Hook Mountain near Pine Brook. Third Watchung Mountains.

Escarpment formed by fault zone
Escarpment formed by the fault zone between the Precambrian Highlands and the Triassic basin (mantled by glacial till).

Entering Dover. Outcrops of Precambrian gneiss.

Crossing an inlier of Silurian rocks north of Dover.
Turning north on Route 15. Crossing an inlier of Silurian rocks north of Dover.

Visit to the mining property.
Sterling Hill Mine office of the New Jersey Zinc Co. Visit to the mining property.

Gerstmann's Private Museum of Franklin and Sterling Hill minerals, 14 Walsh Road, Franklin, N. J.

Oak Ridge Reservoir.
Northwestern border of graben in Precambrian gneiss -- inlier of Silurian and Devonian rocks. Southeast of Charlottesburg the rocks are Precambrian. The fault line separating the Highlands from the Triassic basin is crossed at Riverdale.

Triassic diabase sill.

E: TACONIAN ISLANDS AND THE SHORES OF APPALACHIA
By Robert M. Finks, Queens College of the City University of New York
Within the Precambrian Highlands of northern New Jersey and adjacent New York are several infolded and infaulted belts of Paleozoic sediments. The easternmost of these belts, the Green Pond - Schunemunk outlier; preserves Silurian and Devonian rocks as well as Cambrian and Ordovician. The mid-Paleozoic sediments lie some 25 miles farther southeast than the main outcrop belt of the miogeosyncline, and represent a sampling of material deposited approximately that much nearer the source. They provide a record of those tectonic events and geographic conditions in the source area whose influence did not spread far enough to become manifest farther west.

E: TACONIAN ISLANDS AND THE SHORES OF APPALACHIA

Start of a spectacular new cut in the Palisades Diabase.

End of new cut
End of new cut, now overlying baked shales of the Newark Series may be seen, parallel to the top of the sill.

Meanders of the Hackensack River on its flood plain.

Road follows Passaic River flowing south.

Cut in First Watchung Basalt
Cut in First Watchung Basalt, an extrusive lava. Note curvicolumnar jointing.

Fanned columnar jointing
Fanned columnar jointing followed on LEFT by pillow-lava.

Passaic River flowing north in subsequent valley
Passaic River flowing north in subsequent valley between First and Second Watchung ridges. This is upstream from where we last saw it. It crosses First Watchung Ridge at Paterson Falls.

Second Watchung Basalt.

Third Watchung (Hook Mountain) Basalt.

Wisconsin terminal moraine.

Third Watchung (Hook Mountain) Basalt again.
Third Watchung (Hook Mountain) Basalt again. This has been bent around as part of a syncline in the Newark Series.

STOP 1. Pompton Lakes. Triassic Border conglomerate.
Turn left into Moyias Road and park. Walk across road (CARE!) and north along grass (STAY OFF PAVEMENT!) to outcrop.
(Wanaque, N.J., 7 1/2 - minute Quadrangle.)
This outcrop provides a sampling of the exposed bedrock that lay immediately to the west of here during late Triassic time. Coarse conglomerates such as this are confined to the immediate vicinity of the Triassic border fault and were apparently deposited as alluvial fans at the base of the fault scarp by east-flowing streams. No Precambrian pebbles can be recognized in this outcrop and presumably the Precambrian, now exposed in the hills immediately to the west, still lay covered beneath Paleozoic sediments. Large rounded cobbles, some more than a foot across, of a conglomerate of white quartz pebbles in a red quartzite matrix, closely resemble existing outcrops of the Silurian Green Pond Formation or the Devonian Skunnemunk Formation, both exposed in the outlier some ten miles west of here. Of more interest for the reconstruction of the paleogeography of the pre-Silurian uplift, is the abundance of white-weathering dolomite cobbles that could only have come from the Cambro-Ordovician carbonate sequence. These cobbles are sometimes less well rounded than the quartzite cobbles and must have been transported for no very great distance. The base of the Silurian rests directly on the Precambrian ten miles to the west. The CambroOrdovician carbonates were probably exposed somewhere between there and here in Triassic times and therefore could not have been removed during the pre-Silurian uplift. We will see at STOP 2 that the Trentonian phyllites are still preserved in this vicinity. These data place the eastern border of the pre-Silurian uplifted and eroded area as somewhere between here and STOP 3, only ten miles to the northwest.

STOP 2. Riverdale - Pomton. Annsville Phyllite.
(Pompton Plains, N. J., 7 1/2 - minute Quadrangle. )
After looking at the outcrop we will take a short REST STOP in the Riverdale Diner.
Walk east a little more than a block on the south side of the Hamburg Turnpike, crossing the bridge over the Wanaque River, and descend to the south side of the east abutment of the bridge. Here is exposed a small, but apparently genuine, outcrop of black phyllite; the outcrop is submerged at high water.
This outcrop was mapped as Hudson Schist in the USGS Passaic Folio (Darton, et al. , 1908) a name applied to the rocks now called Manhattan Schist, as well as to the metamorphosed pelites of the upper Hudson Valley now referred to the Normanskill - Snake Hill sequence (Ordovician, Trentonian). I see no reason to question these correlations. This outcrop is called Annsville here because it occurs in the same structural position as the type Annsville at Peekskill, 30 miles to the northeast along the Triassic border fault, and because it resembles the type Annsville lithologically. It also resembles lithologically ( and structurally: refolded foliation) the phyllitic phase of the Mount Merino Formation in Balk's classic area in Dutchess County, as at Noxon near Lagrangeville. Near Clinton, New Jersey, 40 miles to the southwest along the border fault, a sizable patch of the Cambro-Ordovician sequence is exposed between the Triassic and the Precambrian. The Ordovician pelites in it were mapped as Martinsburg Shale (Bayley et al., 1914).
The present outcrop was interpreted in the Passaic Folio as a fault sliver, or "horse, " along the Triassic border fault. It is also possible that the pre-Triassic basement is generally much closer to the present surface along the border fault than usually reconstructed, and that much of the Triassic subsidence was taken up by faulting or warping farther east beneath the basin. The Cambro-Ordovician area near Clinton was mapped in the USGS Raritan Folio (Bayley et al., 1914) as lying uncomformably beneath the Triassic, and the present outcrop may have the same relationship.

Glacial lake delta on left. We have crossed Triassic border fault.

Outcrops of Precambrian gneiss.

Cut in Wisconsin till on left.

STOP 3. Newfoundland: South end of Kanouse Mountain.
Green Pond Formation. (Newfoundland, N. J., 7 1/2 minute Quadrangle. )
Walk north across old highway to nearest outcrop on north side of road. These are the lower conglomerate beds of the Silurian Green Pond Formation dipping steeply northwest. The conglomerate occurs in rhythmically repeated, upwardly-fining, 2 or 3 foot, cross-bedded units. Most of the pebbles are rounded milky-quartz, but red chert, dark shale, and other rock types occur.
Walk uphill, northeastward into the woods, paralleling the base of the cliffs but keeping about 50 feet east of them. About 100 feet or so into the woods large talus blocks of the lowermost beds are passed. They are more coarsely conglomeratic, and contain many angular or subangular pebbles, a few inches across, of green chert, red chert, quartz hematite phyllonite, quartzite, dark shale or slate, along with milky-quartz.
Another hundred feet or so further will bring you to the first outcrops of Precambrian Gneiss. An interval of 25 feet or so, covered with large talus blocks of Green Pond separates the nearest Precambrian outcrops from the exposures of Green Pond in the base of the cliffs. The contact is not exposed.
Return, following the base of the cliff as closely as talus and underbrush permit. At a point opposite the first ledges seen near the road, climb up to a broad rock surface on top of these ledges to observe spectacular Liesegang rings of hematite developed in the finer-grained layers of the rhythmic sequences. (WATCH YOUR STEP.)
Return to the road, cross the old highway and continue west across the grass plot to the main highway. Walk west along the shoulder (STAY OFF HIGHWAY! WATCH TRAFFIC!) to a cut in the Upper Quartzite Member of the Green Pond. The cut shows a small anticline and syncline parasitic upon the main synclinal structure (drag folds). A prominent thin pebble bed makes a convenient stratigraphic marker. Note well-developed quartz-filled gash-fractures along minor shear zones. At the westernmost end of the cut the lowermost red arkose beds of the Lower Arkose Member of the Longwood Formation are exposed in contact with the top of the Green Pond. These beds will be seen in the same stratigraphic position at Highland Mills (STOP 6-A).
(Note: A complete section between the basal beds and the Upper Quartzite Member is exposed in the woods along the south end of Kanouse Mountain, but we will not take the time to visit it. The Middle Arkose Member seen at the north end of the outlier (STOP 5) does not seem to be present here. )

Oak Ridge Reservoir.
Crossing high-angle fault between outlier and precambrian forming west boundary of outlier. Fault-line scarp visible to left along west shore of reservoir.

Flood plain of Pequannock River.

Entering small outlier of Cambro-Ordovician.

Outcrop on right of Cambro-Ordovician carbonate.

Dump of old Buckwheat zinc mine on right.
Franklin minerals may be collected here (fee). Outcrops of Precambrian Franklin Marble.

STOP 4. Hardyston - Precambrian Unconformity and Stissing Dolomite.
(Franklin, N.J., 7 1/2 - minute Quadrangle.)
Walk east from Wildcat Road toward golf course just south of point where wooded ridge intersects road obliquely. Walk northeast along east base of ridge facing golf course about 25 feet to first outcrops. Here Lower Cambrian Hardyston Formation rests on light colored Precambrian gneiss. The Hardyston dips 550 NW. The basal five feet or so of the Hardyston contains pebbles of quartz and fresh feldspar up to an inch in diameter. About 20% of the pebbles are feldspar. PLEASE DO NOT HAMMER ON THIS OUTCROP. Exposures of the Cambrian - Precambrian unconformity are rare and should be preserved as an exhibit for students.
The type locality for the Hardyston is 2 miles to the northeast at Hardystonville along this same continuous outcrop belt. The Hardyston here is in one-foot beds that are internally cross-bedded in smaller units. The five feet or so of conglomerate grades upward into dark-gray, flaggy, quartz-sandy dolomite that underlies most of the ridge and totals about 100 feet in thickness. The dark-gray dolomite may represent the Lower Cambrian Stissing Dolomite.
Climb over the ridge across strike to Wildcat Road and walk north along the road past a covered swale to the next outcrops. These may be the base of the Upper Cambrian Pine Plains Formation. The light-weathering dolomite is interbedded with thin, ripple-marked beds of quartz-sandstone. Oscillation and interference ripples are beautifully displayed both on bedding surfaces and in cross-section. An extensive section of higher carbonate beds is exposed along the road for several hundred feet.
The base of the Hardyston represents a shore, but not a shore of Appalachia. The Early Cambrian sea transgressed westward onto the craton. The importance of this outcrop is to show that the Precambrian which was exposed at the surface at Newfoundland, during the Silurian, is still covered by the Cambrian at Franklin, only 10 miles to the west.

STOP 5. Gould Quarry. Unconformity of Silurian on Cambrian.
Although here called STOP 5, because of the addendum, it was originally called STOP 4A.
(If time permits.)
(Newfoundland, N.J., 7 1/2 minute Quadrangle.)
Walk west into woods following old dirt road to abandoned . and overgrown Gould limestone quarry. The first exposures are of Precambrian gneiss. A few feet of covered interval are succeeded by ledges of Hardyston Sandstone outcropping on the east side of a low ridge. The Hardyston dips steeply northwest and grades upward from a few feet of pebbly quartzite to a quartz-sandy dolomite, that forms the top of the ridge. Walcott (1893) found Olenellus in this dolomite a mile or so to the north, and it is presumably the equivalent of the Lower Cambrian Stissing Dolomite of New York. Just over the crest of this ridge, on its western slope, and about 60 feet stratigraphically above the Hardyston quartzite, the dolomite is succeeded abruptly by a coarse quartz-pebble conglomerate that rests on the irregular upper surface of the dolomite and includes clasts of dolomite just above the contact. This coarse conglomerate appears to be the base of the Green Pond Formation, for it is exposed intermittently from this point westward, across a narrow valley to the main mass of the. formation in Kanouse Mountain. The upper surface of the dolomite, on which the Green Pond rests, is a karstic surface, for pockets of the same conglomerate appear in the basal part of the dolomite, on the east side of the ridge toward the south end of the old quarry, not far above the Hardyston Quartzite. Kfunmel and Weller (1902" pp 7) were apparently the first to interpret these pockets as solution cavities filled from above. The pockets are lined with a thin layer of shaly sediment between the dolomite and the conglomerate. These solution fissures extended some 30 feet below the pre-Silurian surface.
This locality is about three miles north of STOP 3 where the Green Pond rested directly on the Precambrian. The Cambrian first appears beneath the Silurian a half-mile south of here at the north end of Echo Lake. The obvious unconformity here, barely 70 feet above the base of the Cambrian, is the strongest evidence for the unconformable nature of the less well exposed Silurian-Precambrian contact to the south~ We are here on the northerly flank of the pre-Silurian uplift.
Dr. Barnett has discovered Ordovician shales on the west side of the outlier northwest of Bowling Green Mountain. Inasmuch as the Silurian rests directly on the Precambrian at Bowling Green Mountain, the northern limit of the exposed Precambrian lay just north of there. A line connecting that point with the corresponding contact at the north end of Echo Lake should be parallel to the axis of the pre-Silurian uplift. It has an ENE-WSW trend that is at variance with the axis of the outlier, though one that corresponds with late folds in the New York City group in Westchester County (see Trips A and H as well as Fisher et al., 1961.) This m~ be a late Taconian fold direction. I~ also parallel with the Cambrian-PreCambrian contact on either side of the outlier south of Monroe (see Figures 1 and 2.) Unfortunately the Silurian is faulted out of the outlier at that point so that the trend cannot be demonstrated to be pre-Silurian there.

Outcrop of Cornwall (Pequannock) Shale (Middle Devonian).
Outcrop of Cornwall (Pequannock) Shale (Middle Devonian). The road follows the strike of the Upper Silurian-Lower Devonian. On the right is the ridge of Green Pond Conglomerate, on the left the ridge of Bellvale Sandstone.
This comment was on the original trip before the new stop was added. Hence the route no longer comes this way...

Greenwood Lake
To the right is Greenwood Lake. Beyond it to the east are hills of Precambrian forming the east boundary of the outlier. The Green Pond has been faulted out. To the left are nearly continuous outcrops of the lower beds of the Bellvale Sandstone (or the upper part of the Cornwall shale). The ridge to the left (west) is Bellvale Mountain, the type locality of the Bellvale Sandstone.

Woodbury Falls
Woodbury Falls, where railroad trestle crosses road. Marine beds of Bellvale sandstone in bed of Woodbury Creek on right, non-marine beds on left (west) side of road.

Precambrian hill on left (north) and Siluro-Devonian hill on right.

STOP 6. North end of Pine Hill. Green Pond Formation.
Although here called STOP 6, because of the addendum, it was originally called STOP 5.
(Popolopen Lake, N. Y., 7 1/2 - minute Quadrangle.)
Outcrops near the road, at turn-off of private dirt road, are of Lower Conglomerate Member, dipping steeply northwest. The pebbles are almost entirely milky-quartz.
Walk into the woods across strike. About 100 feet NNW are outcrops of the Middle Arkose Member. Fresh, angular, cleavage fragments of feldspar, up to 1/2 inch across, are common along with quartz pebbles in a fine reddish matrix. This unit can be recognized 2 1/2 miles to the southwest along strike near Highland Mills (Figure 4 and Table 1).
Continue 200 feet or so further northwest to the base of ledges that expose the Upper Quartzite Member. (Some care should be exercised to avoid Copperheads in climbing over these ledges.)
Beyond this the Longwood is poorly exposed on the top of the ridge. We will see a better section at the next stop.
Return to the road.

STOP 7. South end of Pine Hill.
Although here called STOP 7, because of the addendum, it was originally called STOP 6.
Green Pond - Longwood - Decker Ferry. (Popolopen Lake, N. Y., 7 1/2 - minute Quadrangle.)
Walk north along Skyline Drive from intersection with Pine Hill Road. The first outcrops on the right (east) side of road are of the Upper Quartzite Member of the Green Pond, with characteristic Liesegang rings of hematite, and quartz-filled fractures.
Farther on the Lower Arkose Member of the Longwood is exposed in poor outcrops. If time permits, climb the hill to the well-exposed ledges on top of the ridge. The lower part of the measured section (Figure 4 and Table 1) was made here, from the Lower Arkose Member of the Longwood down to the Middle Arkose Member of the Green Pond; the section in the Green Pond was measured with several jogs northeastward along strike to preserve continuity of section. The intergrading contact of the Green Pond and Longwood is well exposed here. Do not go further up-section (northwest) than the lower beds of the Lower Arkose Member of the Longwood: the ground slopes downward to the unprotected edge of a sheer 100-foot cliff that drops vertically into the shale quarry to the northwest. STAY AWAY FROM THE EDGE OF THE CLIFF!
Continue north on Skyline Drive to the entrance to the shale quarry and turn right into the quarry. steeply northwest-dipping bedding planes of the Upper Shale Member of the Longwood form the southeast wall of the quarry, higher beds being exposed stepwise toward the north. A zone of contorted bedding is exposed just above the first large bedding plane. Mud-cracks and curious spheroidal pits one to six inches in diameter, are common on some of the higher bedding planes.
The remainder of the section was measured at the northeast end of the quarry, where the Decker Ferry Formation is exposed, separated from the highest beds of the Longwood by a 40-foot interval covered with red shale debris. Some of the Decker Ferry is covered by a few inches of soil, but can be exposed by digging with the hammer. The beds seem to be in place and were measured inch-by-inch with a tape. Most of the formation consists of interbedded quartz-sandstone and dolomite. Quartz-sandstone predominates in the lower beds and this part is here called informally the "Binnewater" Member because it is homotaxial with the type Binnewater of the High Falls area, 40 miles to the north. A prominent outcrop (Unit R) of this lower part of the Decker Ferry is exposed half-way up the slope at the northeast end of the quarry, to the right of a grassy embankment.
Higher in the section thinly laminated (stromatolitic?) mud-cracked, somewhat argillaceous dolomites predominate, with minor quartz sandstone interbeds. Intraclasts are common. This part of the formation is designated informally as the "Waterlime" Member. It resembles lithologically the waterlimes of the Rondout Valley which lie above the Binnewater Sandstone at its type locality. Outcrops may be seen lower on the slope and towards the northwest.
The continuous alternation of the two rock types, sandstone and dolomite, with mud-cracks in the dolomite often being filled with quartz-sandstone, suggests that the two types of sediment were being deposited contemporaneously in adjacent, spatially shifting areas, perhaps sandy beach and tidal mud-flat. (Southard, 1960, mapped the "Binnewater" and "Waterlime" units together as his sandy-claystone unit, emphasizing their continuity. )
The highest beds of the Decker Ferry are lithologically quite distinct, though sandstone & dolomite interbeds indicate their relationship to the underlying units. This unit is separated as the Skyline Calcarenite Member of the Decker Ferry Formation (new name). It includes all the calcarenite beds exposed in the quarry, its type section (see measured section, Table I). Minor interbeds of sandstone and dolomite are present. The principal lithology is a red to blue-gray coarse crinoidal clastic limestone, full of whole shells (see faunal list), cross-bedded, and heavily charged with hematite, which frequently partially replaces some of the fossils. The fauna has not been completely studied but the following have been tentatively recognized:
Bryozoa:
Ptilodictya sp. cf. P. frondosa Weller
massive trepostome, cf. Monotrypa corrugata Weller
Brachiopoda:
Atrypa "reticularis"
rhynchonellid, cf. Camarotoechia sp.
Coelenterata:
Favosites sp.
horn coral
Arthropoda:
ostracode, cf. Dilbolbina sp.
Echinodermata:
pelmatozoan (Probably crinoid) columnals
This fauna is hardly diagnostic of age, but is consistent with the Decker Ferry of New Jersey (Weller, 1903). Neither the fauna nor the lithology are anything like either the Wilbur Limestone or the Glasco Limestone, which fall into this part of the section in the Rondout Valley. Neither is it like any of the higher limestones of the Helderberg Group. The Becraft is the closest lithologically, and probably environmentally, but the fauna is certainly not the same. This appears to represent a shallow-water shell-bank environment. The name of the member is derived from the nearby Skyline Road.
Thicknesses of the members recorded in this section are as follows:
| Feet | Inches
Decker Ferry Formation | |
Sky line Member | 7 | 8
"Waterlime" Member | 28 | 9
"Binnewater" Member | 22 plus |
Longwood Formation | |
Upper Shale Member | 88 | 2
Lower Arkose Member | 80 |
Green Pond Formation | |
Upper Quartzite Member | 222 | 10
Middle Arkose Member | 82 plus |
Walk back out of the quarry, south on Skyline Road and west on Pine Hill Road. At the bridge over the Thruway one can see the Lower Arkose Member of the Longwood exposed north of the east abutment. On the west side of the Thruway, the first visible outcrop is that of the Connelly Conglomerate. When the writer first visited this cut in 1954, just after it had been partly blasted through, a white-to-violet-mottled, friable, clayey, fine sandstone, with characteristic thin inter laminae of dark-gray shale crumpled to give the rock a "zebra-stripe" appearance, was exposed to, the south of the Connelly. It has since been grassed over. Boucot (1959) named this unit the Central Valley Sandstone, and this is its type locality. North of the Connelly, on both sides of the Thruway, is a nearly complete section of the Onesquethawan Series. Access to the Thruway cut is prohibited and the prohibition strictly enforced by State Police.
Continue west on Pine Hill Road to the first black-top road on the right and walk up this road to its dead end.
STOP 6-B. Connelly Conglomerate.
Low ledges on the east side of the road expose the rather well-sorted quartz-pebble conglomerate (2 to 6 mm clasts) of the Connelly. Oriskany fossils establish its age. It is equivalent to an argillaceous limestone 25 miles to the west and to a similar conglomerate followed by an argillaceous limestone 40 miles to the north. This represents a shoreline facies, a pebbly beach on the temporarily stable shore of Appalachia. Most of the fines have been winnowed out.
It may be possible to find Central Valley float on the ground to the south.
Walk back to Pine Hill Road and turn right. At the bend in the road is a stone fence made of Connelly boulders, resting on small outcrops of the Connelly. Where road bends sharply to the left, turn right on private road, then take short path down to railroad tracks opposite abandoned station. Turn right and walk to first outcrops on east side of tracks.
STOP 6-C. Highland Mills. Highland Mills Sandstone and "Middle Member" of the Esopus Formation. (Popolopen Lake 7 1/2 - minute Quadrangle. )
WATCH OUT AND LISTEN FOR TRAINS. DO NOT SIT ON TRACK OR PLACE OBJECTS ON TRACK. TRAINS COME THROUGH FAST AND WITHOUT WARNING. If a train comes stand well back; there is plenty of room on either side of the track.
This stop demonstrates near-shore and off-shore deposits under conditions of strong influx of terrigenous clastics. The series of beds at the south end of the cut are of the upper part of the Highland Mills Sandstone of Boucot (1959). These light-blue-gray, light-brown-weathering, subgraywackes are dominated by evidences of shallow-water deposition. A prominent set of bedding planes display oscillation ripples of various sizes. The ripples tend to be uniformly oriented, roughly NNW - SSE when rotated back to horizontal. (The beds here strike N 500 E and dip 600 NW.) Just north of the ripple-marked layers are lenses of closely packed, jumbled, disarticulated shells. The lenses pinch out within a few feet, from thicknesses of a foot or so. (Preservation on the weathered surfaces is in the form of molds; the most common fossil is Leptocoelia flabellites, but besides the many other brachiopods described by Boucot (1959) there occur gastropods, pelecypods, horn corals, trilobites and other fossils.) Associated with the shell-lenses are shaly beds packed with the ichnofossil Phycodes. All these features are characteristic of the Cruziana-facies of Seilacher (1964) representing shallow-water above wave-base, littoral or sub-littoral.
The "Middle Member" on the other hand, exposed farther north along the tracks, represents Seilacher's deeper-water, sublittoral to bathyal Zoophycos-facies. Bedding planes are covered with the ichnofossil Zoophycos (= Taonurus, = Spirophyton). The rock is massive-bedded and the bedding planes very even. (The rock weathers brown to orange, the fresh rock is almost black.) Although described in the literature as a mudstone, most beds are poorly-sorted graywacke sandstone with about 55% to 85% quartz-grains of fine-sand size, and the rest chiefly finegrained matrix (data from Miss Janice Lumnitz and Mr. Maury Morgenstein). Fossils are sparsely scattered on the bedding surfaces, mainly the brachiopods Leptocoelia flabellites and Spirifer macra. On many bedding-planes concave-up valves outnumber concave-down valves (from Miss Janice Lumnitz) suggesting settling-out through water followed by rapid burial without further reworking. The unsorted nature of the sediment also points to rapid sedimentation and the sparseness of fossils suggests dilution by rapid influx of terrigenous material.
Feldspar may be less abundant here than in the underlying Highland Mills Member, but the whole Esopus sequence is strongly suggestive of a pulse of erosion of the source area (Appalachia).
The Esopus sequence starts with deep-water Zoophycos-bearing beds (the Mountainville Member of Southard, 1960). The upper part of the Highland Mills Member (restricted Highland Mills Member of Southard) is mostly shallow-water. The "Middle Member" is· again mostly deeper water. The Woodbury Creek Sandstone appears to be mostly shallower water again. It is more fossiliferous than the "Middle Member" (dominated by the pelecypod Cypricardinia and the brachiopod Schuchertella). The fossils are evenly spread on the bedding planes, rather than in lenses as in the Highland Mills Member, and ripple marks are not well-developed. Also Zoophycos has been observed on some beds. It would thus seem to be of a depth intermediate between that of the Highland Mills Member and that of the "Middle Member".
The succeeding Kanouse Sandstone, a clean, somewhat pebbly, orthoquartzite, again marks a stable shoreline deposit, with a falling off of terrigenous influx permitting better sorting of the material. It appears to be the shoreward equivalent of limy deposits to the north and west (Schoharie and/or Onondaga).

STOP 8. Monroe. Bellvale Formation.
Although here called STOP 8, because of the addendum, it was originally called STOP 7.
(Monroe, N. Y., 7 1/2 - minute Quadrangle.)
Between here and the Monroe-Washingtonville exit are exposed about 2000 feet of the Bellvale Formation, essentially a complete section. Details of the section are given in the measured section, Table II and Figure 5.
The lowest beds at the east end of the outcrop are shaly siltstones that are close to the base of the Bellvale, if indeed they are not to be considered the highest beds of the underlying Cornwall Shale. The beds immediately above are graywackes that carry Mucrospirifer and Spinocyrtia, thereby demonstrating their Hamilton age and marine nature. A small Chonetes is also common. This entire lower part of the section here is identical, lithologically and faunally, to the section exposed in the bed of Woodbury Creek, at Woodbury Falls, north of Highland Mills, where the railroad trestle crosses Route 32.
As one goes up-section, intercalated beds of uncleaved sandstone increase in thickness and ultimately dominate the section by the time one reaches the abutment of the overpass. Up to here the beds are evenly laminated without any indication of large scale cross-bedding or channeling.
Just at the east side of the overpass is a zone of ball and pillow structures and load-casts. These structures are widely recognized in the Catskill Delta rocks as marking the transition-zone from marine to non-marine beds. The beds beneath the overpass are still marine, however, as brachiopods have been found in them. Nevertheless, the nature of the bedding changes from the preceding even lamination, to evidence of channeling, cut-and-fill structure, and cross-bedding. The rock becomes lighter and coarser, a subgraywacke. Load-casts are present intermittently, and at least one zone of pebbles scattered in subgraywacke is present. It would appear that we have passed from the evenly laminated prodelta and foreset beds to channeled 3l1d irregular top set beds.
West of the overpass the subgraywacke becomes still coarser and lighter. Thin interbeds of shale become more common and numerous shale chips appear in the sandstones. Many of the smaller grains appear to be shale clasts or perhaps phyllite. Obscure plant remains and possible wood-fragments appear. No marine fossils have been found, and these deposits may have been made on the subaerial part of the delta.
Beyond the culvert the rock becomes even coarser and more lithic. Here unmistakable plant fragments are present including pieces of branches of scale-trees or related lycopsids a half-inch or so in diameter and clearly shoWing the leaf scars and internal woody fibers. (The first such were found by Mr. Harvey Zeiss; I have since found others.) Note the well-developed glacial striae and chatter-marks on some of the outcrop surfaces.
Beyond this point is a long succession of massively cross-bedded subgraywacke sandstones with shale interbeds. There are also four prominent units of highly cleaved mudstone, decreasing in thickness from 31 feet for the first such unit, to 11 feet for the last. These are probably flood -plain muds. The last of these units is clearly channeled and filled by the succeeding sand , probably a stream-channel deposit.
The Bellvale section ends with coarse pebble beds at the center of the syncline, just at the Monroe-Washingtonville exit. These beds have the character of the overlying Skunnemunk Formation, except that they lack the red color characteristic of that formation. The pebbles include besides milky-quartz, rocks such as chert, quartzite and shale or slate, not too unlike the pebbles included in the base of the Green Pond at STOP 3. We are probably dealing here with Piedmont alluvial deposits.

Return to the hotel
Return to the hotel via Route 17, New York State Thruway, Major Deegan Expressway, etc.

F: THE PLEISTOCENE GEOLOGY OF THE MONTAUK PENINSULA
By Walter S. Newman, David L. Thurber, David H. Krinsley,
Queens College of the City University of New York;
and Leslie A. Sirkin, Adelphi University.
Long Island is a long narrow island reaching east-northeastward from New York City to form a "fish-like" extension of New York State. The island lies south of and is approximately parallel to the Connecticut shore of New England and is separated from it by Long Island Sound. Long Island forms the north shore of an Atlantic Ocean reentrant known as the "New York Bight". Although part of the Coastal Plain Physiographic Province, Long Island features a topography almost completely modified by glacial and proglacial processes. Two conspicuous end moraines extend from west to east along the axis of the island. The older Ronkonkoma moraine, probably Wisconsin in age, makes up a major portion of the Montauk Peninsula. The younger Harbor Hill moraine generally follows close to the north shore of Long Island east to Orient Point. The island abounds in other glacial and proglacial features such as the coalescing outwash fans and aprons which form much of the southern portion of the island.

F: THE PLEISTOCENE GEOLOGY OF THE MONTAUK PENINSULA

Flushing Meadow
Flushing Meadow-the site of the two New York World's Fairs. The geology of this swale has been described by Newman (1966).

Queens College
To your right (south) the campus of Queens College of the City University of New York.

Alley Creek Valley
A drowned and then partially filled embayment of Long Island Sound.

Lake Success on your right
The lake has an area of 60 acres, a maximum depth of 72 feet, no surface outlet, and is one of the larger kettles on Long Island. Note the (both) Ronkonkoma and Harbor Hill morainal topography.

Descend from Ronkonkoma moraine
Plainview(!)-Here we descend for a short distance from the Ronkonkoma moraine onto the outwash plain. Note the relief contrast.

Descend to the Huntington Plain
After crossing West Hills, one of several central Long Island areas where pre-Pleistocene strata rise considerably above sea level and approach the surface, we descend to the Huntington Plain which may be the site of a proglacial lake overlain by a thin veneer of outwash (Lubke, 1964).

Half Hollow and Dix Hills
We rise again into the Half Hollow and Dix Hills, areas similar in structure to West Hills. The Ronkonkoma End Moraine lies on the north flanks of these hills.

Outwash plain then Ronkonkoma moraine
Sunken Meadow-Sagtikos State Parkways. Here we descend once again for a short time onto the outwash plain. Pilgrim State Hospital forms the large building complex on the right (south). We then once again mount the Ronkonkoma moraine.

Descend from Ronkonkoma Moraine to outwash plain
We descend almost immediately from the Ronkonkoma Moraine onto the outwash plain. Note the distinctive "pine barrens" vegetation of scrub-oak and pine. This area is underlain by a podzol soil having a bleached lower "A" horizon. This area of Long Island is devoid of agricultural potential because the outwash lacks the loess cover which is conspicuous in farming areas on outwash further east.

Continue east through "pine barrens" on outwash plain.

Eastport: temporary terminus of Sunrise Highway.
Northeast on Route 51. Note farming activity on outwash plain. The surficial loess makes the difference! Route 51 climbs onto the Ronkonkoma moraine and then descends towards Riverhead and the pitted outwash plain between the Ronkonkoma and Harbor Hill End Moraines.

Riverhead: at the Peconic River mouth.

Reeves Bay on left (north).

Cross Shinnecock Canal. We mount the Ronkonkoma Moraine once again.

Bluff Road
Bluff Road marks the crest of an abandoned wave-cut marine cliff cut into Ronkonkoma outwash. Progradation due to the construction of the Napeague Tombolo has separated the bluff from the sea for distances of up to 1.5 miles.

Descend from bluff
We descend from the bluff, now on our left onto the Napeague beach-and-dune-complex Tombolo.

Abandoned wave-cut bluff on left
Note the abandoned wave-cut bluff on left as well as the dunes on glacial drift. Drive half-left onto the New Montauk Highway mounting the Ronkonkoma Moraine at Hither Hills.

The village of Montauk built, for the most part, on a double tombolo.

STOP 1. Montauk Point State Park, Montauk Point.
45 minutes. REST ROOMS ARE IMMEDIATELY ADJACENT TO THE PARKING LOT ENTRANCE. Montauk Lighthouse was built in the years 1795-1797 about 300 feet from mean high water. It is now only about 60 feet from the water's edge. Following the field trip leaders, walk southeast crossing the road (WATCH OUT FOR TRAFFIC!) and follow the trail which commences at the lighthouse reservation entrance and skirts the south boundary down to the water's edge. To your left, towards the lighthouse is the section sketched by Fuller (1914, fig. 159, p. 144) which probably includes the type Montauk Till section. Starting from the base, Fuller identified the units in the bluff as "(a) Till phase of Montauk till member; (b) boulder pocket; (c) sand and clay phase of Montauk member; (d) clayey sand phase of Hempstead gravel member; (e) normal sandy phase of Hempstead gravel member". We interpret this section as consisting of Ronkonkoma (=Montauk) Till; a lag concentrate; laminated, probably lacustrine, silt, sand and clay; grading upwards into eolian silt and sand. Over towards the northeast, the section includes some stratified drift. The laminated unit appears to occupy a swale (kettle?) in the till. Listen (sic!) to the geomorphology and sedimentology. Returning to the busses, climb the bluff and look southwest. The bluffs are usually fringed by steep shingle-beaches and extend four miles southwestward to Ditch Plains.

Montauk Air Force Station.
Stop! We are now under military jurisdiction and supervision. Proceed under Air Force direction to south shore.

STOP 2. South Shore Beach
1 hour. Leave the buses and enter upon the south shore beach. Immediately to the west is a mass of laminated silt and fine sand which Fuller considered "possibly" Gardiners. We believe this unit represents a proglacial lacustrine deposit. Walk southwest for 0.5 mile. Here we find the exciting section described by Perlmutter and DeLuca (1963). The major unit is the Montauk Till forming a 0.5 mile long open anticline. The Montauk Till overlies stratified drift consisting of interbedded gray and brown clay, laminated green and gray silt and clay, and some thin lenses of fine brown sand. Perlmutter and DeLuca found neither forams nor diatoms in the lower stratified drift which represents the oldest unit we will view on this trip. Immediately above the Montauk Till is stratified drift which ranges in thickness from a featheredge to about 30 feet and is composed chiefly of beds and lenses of brown and gray silt, fine to medium sand, and clayey sand. We interpret this unit as likely to be proglacial lacustrine in origin. Perlmutter and DeLuca report 5 to 20-foot-thick till unit on top of the upper stratified drift. However, Newman fails to note it. Occasional pockets of loess cap the section.

Note the morainal topography and surface erratics on right.

STOP 3. Montauk Airport Archeological Site.
30 minutes.
Geologically, this site includes a medley of till and ice-contact deposits including lenses of red-brown clay, silt and fine sand which Fuller would have referred to as Gardiners Clay. Overlying the drift is a lag concentrate, including occasional ventifacts, while the entire section is capped by loess. Pelecypod valves, including Crassostrea virginica, Venus mercenaria and Pecten irradians, form a "shell midden" associated with the upper portion of the loess blanket. The absence of artifacts suggests the midden dates from the "Archaic Stage" of aboriginal development and is thus some 4000 to 6000 years old. These aborigines probably harvested the lagoon or bay that existed immediately to the north of the site which has since been filled by the tidal marsh sere and then covered with sand dunes.
LUNCH STOP! Perhaps. It depends upon the wind direction. If conditions are unfavorable here, we'll eat at STOP 4.

STOP 4. Ditch Plains Stratigraphic Section.
45 minutes.
Enter upon the beach and walk west 0.2 mile. At this point, the bluff presents a rather simple section consisting of the Montauk Till, a lag concentrate, with loess on top. However, further to the east, additional units are found beneath the loess. These new units of stratified drift appear to have an easterly dip component. At the east edge of the bluff, accentuated by a morphological reentrant at the back of the beach, the stratified drift clearly takes on the aspect of a delta built into a standing body of water. However, this critical exposure is frequently obscured by slump from the still younger unit, aeolian sand comprising dunes, found above the loess. At about this point, the Montauk Till surface dips below the beach and two additional units are found which outcrop near the upper edge of the beach. The lower unit is composed of laminated silt, clay and fine sand. The upper unit is a peat. Both of these units can be traced for about 0.4 mile towards the east although occasionally interrupted by drift, mostly till, cropping out at beach level. Still further towards the east, the bluffs, composed for the most part of Montauk Till, reappear.
Rooted stumps are occasionally found on the peat layer. About a mile to the northeast, adjacent to East Lake Drive and Montauk Harbor, the U. S. Geological Survey notes 98 feet of clay commencing at elevation 0 (Well S010041). The evidence so far developed suggests the entire Montauk Harbor swale was at one time a lake basin. A pollen section from the beach exposure worked up by Maurice Kalisky, one of our graduate students, indicates the sampled section straddles the B (pine) and C-1 (oak-hemlock) Pollen Zones. In this and other aspects, this pollen section resembles that of Donner's (1964) site 2 section from a bluff 0.3 mile west-northwest of Montauk Point. Apparently, a proglacial lake developed a bog sere in postglacial times which was terminated by the Flandrian transgression. The rise in sea level breached the basin rim and littoral and aeolian sand encroached upon portions of the original basin.

Fort Pond
Fort Pond on your left is dammed on both its north and south side by tombolos.

Montauk Station: eastern terminus of the Long Island Railroad.

STOP 5. Ice contact kame
30 minutes.
This excavation illustrates the internal structure of a morphologically well-defined ice-contact kame. Till is exposed at the north side of the pit while a lag concentrate and loess overlie the glacial drift.

STOP 6. Montauk Sanitary Landfill Project
Both the topographic maps and aerial photographs (see Plate 1) of the Hither Hills area feature several dozen northeast striking ridges. Fuller (1914, p.48), referring to the swales between these ridges, called them "inner-fosse channels". He considered them to be erosion channels which were outlets for waters issuing from the ice margin at successive halts and escaping parallel to the ice front. The structure of the stratified drift exposed in this excavation, however, suggests these ridges are ice-thrust moraines. On the west side of the excavation access road, coarser stratified drift, a lag concentrate, and loess are exposed.

View of the Ronkonkoma moraine
In clear weather, the view towards the west gives an excellent view of the Ronkonkoma moraine as well as many grosser shoreline features.

Wave cut bluff and migrating dunes
Continuing west along Route 27, note the wave-cut bluff to your right (north) now isolated from the sea by a prograding shore. The bluff section consists of stratified drift overlain by dune sand now cascading down onto the Long Island Railroad right-of-way. These dunes appear to have migrated in from the north shore.

STOP 7. "Walking Dune".
At the terminus of the paved road, follow path to top of "Walking Dune".
These magnificent parabolic dunes are the present result of a series of morphological developments. Initially, a spit was built westward out from the north shore of Hither Hills. Foredunes were then built behind the beach associated with the spit. Meanwhile, a tidal marsh sere developed in the lagoon behind the spit and the dunes encroached upon and, in large measure, covered the tidal marsh. An oak forest sere developed within the dune swales but were subsequently covered and still later exhumed. Note the dune slip faces currently burying the existing forest.

Crossing Napeague Meadows, a ditched tidal marsh.
UNGUARDED RAILROAD CROSSING-CAREFUL!

Roadcut through Promised Land Chenier.

Chenier on left (south).
Promised Land fish-rendering plant on right; chenier on left (south). The road parallels the chenier for 1. 5 miles.

The chenier ties into the Ronkonkoma Moraine
The chenier ties into the Ronkonkoma Moraine at the east end of the wave-cut bluff marked by Bluff Road. Presumably, the chenier marks the location of a former spit built eastward at the time the sea was eroding along the line of bluff road.

Wave cut cliff
Bluff Road follows the crest of a wave-cut cliff cut into outwash. Some might suggest that the flat below the bluff represents a mid-Holocene three-meter terrace in the sense of Fairbridge. However, it is more likely that the flat is due to prograding Atlantic shore in this vicinity. The present shore cuts the bluff out at Easthampton village.

STOP 8. Bluff Road.
Plate 2 depicts the morphological relationships of the locality. Time permitting, we will walk the 0.4 mile to the Atlantic shore beach.

G: STRUCTURE AND PETROLOGY OF PELHAM BAY PARK
By Carl K. Seyfert, Department of Geology, Buffalo State University College,
and David J. Leveson, Department of Geology, Brooklyn College.
Location and Geologic Setting.
Pelham Bay Park is located on Long Island Sound in The Bronx in New York City (Figure 1). The area mapped in detail (Scale 1 inch = 10 feet) includes North Twin and South Twin Islands which are located in the eastern part of Pelham Bay Park (Figure 2). Both North Twin and South Twin Islands are underlain by highly deformed and intensely metamorphosed gneisses, schists and amphibolites which have undergone a complex tectonic and metamorphic history involving extensive boudinage, tight isoclinal folding and metasomatism. Pleistocene glaciation and recent wave action provide excellent exposure of bedrock and permit detailed field study of these rocks. The units of Pelham Bay Park were mapped as Hudson Schist (now Manhattan Formation) in the New York City Folio (Merrill et al., 1902). However, on the New York State geological map (Fisher et al., 1961), the rocks are designated as undivided schists and gneisses of unknown age.
Acknowledgments.
The authors wish to thank Professor Kurt Lowe of the College of the City of New York who first introduced them to this area, and the late Professor Arie Poldervaart of Columbia University who provided early encouragement and funds for initial thin sections. Thanks are also due the Society of the Sigma Xi for a Grant-in-Aid of Research that permitted continuing investigation, and the Department of Parks of the City of New York for their courtesy and cooperation.

G: STRUCTURE AND PETROLOGY OF PELHAM BAY PARK

STOP 1. Orchard Beach Park (STOPS 1 - 11)
Turn left and follow the road to the parking lot for Orchard Beach and park in the northeastern corner of the lot.
Distance Between Points.
Take the path which leads to the beach and follow the path along the beach to the northeastern end of the beach. The first stop is on the outcrop just east of the Breakwater on the southern end of South Twin Island (Plate 1).
2400'   STOP 1. The rocks here include felsic gneiss, sillimanite schist, and amphibolite. Note the rootless fold in an amphibolite at the north end of the outcrop (STOP I-A. see Plate 1)0 This amphibolite continues along strike into mafic biotite schist on the west limb of the fold. The west limb of the fold was stretched and thinned during the third phase of deformation. A plagioclase-quartz border is present on the amphibolite near the trough of this synclinal fold.
The amphibolites on the eastern side of the outcrop pinch and swell along strike. Note the presence of pegmatite (Table 1, number IS) replacing the amphibolite and mafic biotite schist (Table 1, number 10) in a thin amphibolite layer which has been separated by boudinage (STOP I-B). Mineralogy of the pegmatite: plagioclase, quartz and biotite.
The amphibolite in the center of the thicker amphibolite layer (STOP I-C) contains little biotite (Table 1, number 6), but biotite increases in abundance toward the contact of the amphibolite (Table 1, number 9) with felsic gneiss.
Isoclinal folds can be seen at the south end of the outcrop (STOP l-C, see Plate 1) especially at low tide. The axial planes of these folds strike N200 E and dip SOOE. Fold axes have an average bearing of N440 E and plunge of 620 NE.
Where folding during the third phase of deformation was particularly intense (STOP I-D), biotite within sillimanite schists was rotated parallel to the axial planes (S3) of the latest set of folds (F3)'
Proceed northeastward along the shoreline.
300'   STOP 2. Rootless fold in amphibolite (See Plate 1). A Plagioclase-quartz border (Table 1, number 11) is present at the ends of the amphibolite which have been separated by boudinage. Near the contact with the plagioclase-quartz border, the amphibolite contains diopside, epidote, calcite and scapolite.
Continue northward along the shoreline.
100'   STOP 3. Small normal fault (Plate 1). Slickensides on the fault plane at the western end of the outcrop indicate that the motion was dominantly dip-slip. Erosion of breccia along the fault has produced a small "rift".
Continue north along the western side of the outcrop.
50'   STOP 4. Pegmatite replacing amphibolite. Note the very irregular, gradational contacts. Mineralogy: plagioclase, quartz and biotite. Continue northeastward along shoreline.
100'   STOP 5. En echelon amphibolite layers suggesting the amphibolites were originally dikes or sills. Note replacement pegmatite in the amphibolite.
Proceed northward along shoreline.
200'   STOP 6. Injection pegmatite dike. Walls are generally sharp, but local assimilation of the felsic gneiss has caused some irregular contacts. Mineralogy: microcline, quartz, plagioclase, with minor tourmaline (black), garnet and apatite.
Note large erratics and glacial striations on bedrock.
75'    Another injection pegmatite (STOP 7 -A). Note straight, parallel walls. Layers of sillimanite schist are offset indicating dilation of the wall rocks during emplacement of pegmatite. Contacts are very sharp and muscovite crystals near the contacts tend to be oriented normal to the walls of the dike. This pegmatite almost certainly crystallized from a granitic melt.
Proceed eastward along the shoreline.
225'   STOP 7. Thick amphibolite layer with calcite-diopside-scapolite pods. This mineralogy is similar to that of the diopside-epidote amphibolites of North Twin Island. Cross the tombolo (which may be covered at high tide except for stepping stones) which connects North Twin Island with South Twin Island (Plate I), Continue to large fold just east of the center of the island.
400'   STOP 8. Folded diopside-epidote amphibolite, plagioclase-rich layers (Table 1, number 15), and calcite-rich layers (Table 1, number 16). Folding is somewhat disharmonic within the calcite-rich and plagioclase-rich layers. These layers grade along strike into diopside-epidote amphibolite on the limbs of the fold (Figure 4). Changes in mineral assemblages going from diopside-epidote amphibolite on the limbs of the fold to plagioclase-rich layers along strike at the crest of the fold are:
(a) hornblende-plagioclase with minor pyroxene, scapolite, epidote and calcite;
(b) plagioclase-hornblende-epidote with minor quartz and pyroxene; and
(c) plagioclase with minor quartz and magnetite.
The plunge of the fold is to the south, indicating that it is an antiform (up-arched foliation surface). However, along strike to the north on both limbs of the fold, the plunge of the folds changes to vertical and then to plunging northward. Thus, there are two antiforms along the continuation of the amphibolite layer, with no intervening synform. Sl foliation has been folded about the antiforms.
Just east of the fold, there are several plagioclase-biotite gneiss layers within the diopside-epidote amphibolite (STOP 8-B). Ellipsoidal hornblende nodules occur within diopside-epidote amphibolite near the contact with plagioclase-biotite gneiss on the eastern side of North Twin Island (STOP 8-C). The nodules are 2 to 4cm. in length and 1 to 2 cm. across 'and lie in a calcite matrix. They are separated from the calcite by a 2 to 5mm. wide zone of medium-grained pyroxene and scapolite. A thin rind of epidote surrounds some scapolite grains and separates them from adjacent calcite. Intermediate axes of the ellipsoids are parallel to the foliation and long axes are parallel to mineral lineations in the surrounding mafic gneiss.
Diopside-epidote amphibolite grades along strike into normal amphibolite (STOP 8-D) suggesting that it formed by metasomatism of amphibolite.
Proceed northward.
STOP 9. Replacement Pegmatite. Plagioclase and microcline porphyroblasts are abundant within plagioclase-biotite gneiss near the contact with replacement pegmatite (Table 1, number 17). In fact, the replacement pegmatite is simply a coalesced mass of porphyroblasts. Contacts are gradational and extremely irregular.
Note the plagioclase-biotite selvage surrounding a diopside-epidote amphibolite boudin at the contact of the boudin with replacement pegmatite (STOP 9-A).
A plagioclase-epidote-quartz border is present at the end of a layer of diopside epidote amphibolite which has been separated by boudinage (STOP 9-B). This border grades abruptly along strike into amphibolite (very thin border) and then into diopside-epidote amphibolite. Relict foliation (Sl) is present in the plagioclase-epidote-quartz border. The border, which is 87% plagioclase, 5-1/2% quartz and 4% epidote, developed by metasomatism of diopside-epidote amphibolite. The composition (Table 1, number 12) is similar to that of an anorthosite.
Proceed to the northwest.
75'   STOP 10. Boudins of diopside-epidote amphibolite within plagioclase-biotite gneiss. There are several areas where diopside-epidote amphibolite can be traced along strike into plagioclase-biotite gneiss suggesting that the plagioclase-biotite gneiss was produced by metasomatism of diopside-epidote amphibolite. Steps involved are:
(a) feldspathization of diopside-epidote amphibolite;
(b) conversion to feldspathic amphibolite; and
(c) replacement of hornblende by biotite, forming plagioclase-biotite gneiss.
Calcite-rich layers and pods are present within diopside-epidote amphibolite boudins. Calcite-rich layers are also abundant at the ends of the diopside-epidote amphibolite layers which have been separated by boudinage (STOP 10-A). The zone containing calcite rich layers is 25 feet wide, but it grades along strike (to the south) into diopside-epidote amphibolite containing no calcite-rich layers. This suggests that the calcite-rich layers were produced by metasomatism of diopside-epidote amphibolite.
Note the curved mineral lineations and curved fold axes within the boudins (STOP 10-B). The rotation of lineations and fold axes occurred during "necking" prior to separation of the boudins.
Return to South Twin Island and follow the western shoreline to a gravel road near the center of the western shoreline of the island.
1000'    Take gravel road westward across the bridge to Hunter Island.
900'     Turn right (north) along the east shore of Hunter Island to a small outcrop of felsic gneiss and sillimanite schist just south of a thick amphibolite layer (Figure 2).
1000'   STOP 11. Open fold. Felsic gneiss, sillimanite schist, and biotite amphibolite show evidence of 3 phases of deformation because in this area the last phase of deformation was not intense enough to obliterate signs of the earlier deformations. Biotite and amphibole crystals are oriented parallel to compositional layers within the biotite amphibolite. This foliation (S1) is probably an axial plane foliation formed during an early period of intense deformation. This foliation has been folded about a set of fold axes (L,z) which plunge steeply to the southeast. Large amphibole crystals are oriented parallel to these fold axes. A second foliation (S2) is defined by biotite crystals oriented parallel to the axial planes of the F2 folds within the felsic gneiss. Within sillimanite schist, biotite and sillimanite are oriented parallel to the axial plane (S3) of the latest set of folds. Axes of these folds plunge steeply to the northeast in this area. The relation between the folds and foliations is shown in Figure 5.
Return to the gravel road by taking path southward along the shoreline.
1000'   Take gravel road south to fork in the road.
800'     Take right hand fork and return to the parking lot. We will eat LUNCH on the tables just north of the parking lot.

H: STRATIGRAPHIC AND STRUCTURAL RELATIONS ALONG THE WESTERN BORDER OF THE CORTLANDT INTRUSIVES
Nicholas M. Ratcliffe
City College of New York
INTRODUCTION AND PURPOSE OF TRIP
The New York State Geological Association as recently as 1958 dealt specifically with the problem and areas outlined in this discussion. Recent discoveries by Hall (1965, and this volume), however, have brought the stratigraphic problems of the New York City Group much more clearly to light and have encouraged re-evaluation of the field evidence in this critical area.
The stratigraphic age and correlation of the rocks surrounding the western edge of the Cortlandt intrusives has been clouded by the personal prejudices of individual workers for many years. Because definitive evidence of a stratigraphic kind is difficult to come by in an area as complexly deformed as this, this correlation problem of regional importance is not resolved at the present time.
This trip will focus on one major problem: are the rocks called Manhattan Schist and Inwood Marble south of the Cortlandt intrusives correlative with fossiliferous rocks at Tomkins Cove and Verplanck Point? Lithic and structural arguments will be presented to support this correlation. As in all metamorphosed areas, we must rely primarily on lithic characteristics and stratigraphic succession as well as on structural continuity to solve this kind of problem. The answer is to be found in the rocks; all we must do is look for it.
The purpose of this field trip is to present new stratigraphic and structural data from the western border of the Cortlandt intrusives. This area is critical because it is the locality where correlation of Manhattan Schist and Inwood Marble with the low-rank carbonate rocks and phyllites at Tomkins Cove can best be accomplished. Bucher (1951) demonstrated the lower Paleozoic age of the Tomkins Cove section on the basis of pelmatozoan fragments in a calcareous zone at the base of the phyllite section there (STOP 7-A).
A similar fossiliferous zone rich in pelmatozoan remains has been discovered at Verplanck Point Quarry, on the east side of the Hudson River, demonstrating a Lower Paleozoic age for these rocks (Ratcliffe and Knowles, 1968) (STOP 5). A very similar "crinoidal" limestone is interbedded with the base of the type Annsville Phyllite in the Peekskill Hollow Creek at Van Cortlandtville 1-3/4 miles north of Peekskill. Identifiable fragments of pelmatozoan columnals were found in this rock by participants in the NYSGA excursion of 1958, thus supporting the correlation of Annsyille Phyllite with the phyllites at Tomkins Cove proposed on lithic grounds by Bucher (1951). It is here suggested that the lower unit of the Manhattan formation is correlative with the combined Balmville Limestone and Annsville Phyllite and that both are Mid-Ordovician in age.

H: STRATIGRAPHIC AND STRUCTURAL RELATIONS ALONG THE WESTERN BORDER OF THE CORTLANDT INTRUSIVES

Large outcrops of Yonkers-type gneiss
Note large outcrops of Yonkers-type gneiss with large apparently folded pegmatites.

Numerous exposures of Xma
Continue north along 9A around west end of Prickly Pear Hill. Numerous exposures of Xma (Upper Manhattan, here staurolite grade). Just entering map, Figure 1.

STOP 1. Brinton Bird Sanctuary.
North flank Prickly Pear Hill, NE 1/9 Haverstraw Quad.
This stop is located on the southeast flank of the Tomkins Cove Crugers F1 anticline (Figures 1 and 3), and exposes granitic gneisses of the Fordham Gneiss in near contact with the Lower Manhattan (Oma).
Walk northeast up the path into the bird sanctuary approximately 800 feet to large glaciated exposure of Manhattan schist.
Garnet-quartz-biotite-muscovite-schist and garnet-biotite-muscovite-plagioclase-quartz granulites are the dominant lithologies. Staurolite is a diagnostic mineral in much of Unit B of the Manhattan in this area. This is typical of the Upper Manhattan exposed to the southeast on Prickly Pear Hill and resembles the type Manhattan of New York City despite the lower metamorphic grade.
Closures of F1 folds may be seen in the outcrop with the F1 axial surfaces (with bedding parallel in most cases) trending N45°-50° E and dipping steeply to the east. Late F2 folds with a related crenulation cleavage trend S75°-80°E and have near vertical axial planes and fold the F1 axial surfaces.
An F3 fold system is weakly developed in the north-central portion of the outcrop with axial planes trending S45°-50° E.
Note the several generations of quartz veins, parallel to S1, S2, and S3. S3 quartz is located in short gash-like fractures, suggesting the brittle behavior of the late F3 structure. Note the habit of the large post-kinematic metacrysts of biotite (plates are not oriented in S1, S2, or S3), S1 foliation is developed largely by the orientation of the white mica and lenticular quartz grains.
Walk north into open field to small outcrops of Lower Manhattan. Black, sooty appearance is typical of the Lower Manhattan. Minor dark siliceous layers are common.
Continue north across field noting scattered small outcrops of Lower Manhattan.
Near the edge of the field to north and by stone wall are outcrops of granitic gneiss of the Fordham. Foliation having the orientation of S1 in the schist is present in the gneiss. Compositional layering is difficult to see in the gneiss at this locality, but it commonly is not parallel to S1 (i.e., S1 is superposed on an earlier, probably Precambrian, foliation in the gneiss). There is little room here for the Inwood formation. This gneiss - Lower Manhattan contact has been mapped along the north side of Prickly Pear Hill to a point east of the lake where compositional layering in the gneiss demonstrates the anticlinal closure (see Figure 3).

Outcrops of layered gneisses of Fordham Gneiss
Overpass to Oscawanna on left (roadcut N. Y. 9) outcrops of layered gneisses of Fordham Gneiss dips are north at moderate angles. Granitic gneiss of Fordham can be seen at north end of cut. Underpass for N.Y. 9. Pass exposures on right (east) of layered norite.

Pass outcrops of Manhattan (Xmb) in woods above road.

STOP 2. Maiden Lane Sand Pit.
This stop is located on the opposite (north) limb of the major F1 fold from STOP 1 (Figure 3). Walk into the sand pit starting from the intersection of Maiden Lane and Cortlandt Street.
Layered biotite, plagioclase gneiss is exposed at corner. Foliation and compositional layering dip steeply to the north. Granitic gneiss of the Fordham is exposed in stream bed and on the hill to the south of the stream.
Enter sand pit east of house. The sand pit exposes a section that is a maximum of 50 feet thick, from Fordham Gneiss to the base of the Manhattan Formation.
Walking north into pit, one encounters the various rock units.
Biotite-plagioclase-quartz-gneiss (Fordham)
Lowerre quartzite (right-side-up) 15 ft.
Unit A Inwood white dolomitic marble 10-15 ft.
Unit B Inwood - impure siliceous dolostone with phyllitic layers 20 ft.
Manhattan (Oma) - calcareous, siliceous black metagraywacke, biotite-quartz-plagioclase schist, and lustrous garnet-staurolite-muscovite, biotite quartz schist.
The lower units of Oma are characterized here by concentrations of pale green tourmaline with khaki green overgrowths. Similar zoned tourmalines are present in Oma at STOP 3 and again at Verplanck Quarry (STOP 5).
The dominant foliation S1, sub-parallel to bedding, varies from N80&deg-90 °E and dips 70°-80° to the north. S2, here a well developed foliation (N80°E, 85°S), folds S1 producing east-plunging folds of S1 and S0.
A locally well-developed S3 crenulation cleavage, (N45°-50°E, 90°) cuts S2 and S1 surfaces on a small exposure of Lower Manhattan above the sand pit.
Typical Upper Manhattan (Xmb) can be seen above the sand pit to the northeast. Note abundant refolded F1 folds; east plunging F2 folds dominate the structure. Staurolite-garnet-muscovite-biotite-quartz-plagioclase schists and typical garnet-muscovite-biotite-plagioclase-quartz granulites of the Upper Manhattan are exposed. Kyanite has been found with staurolite in exposures of this unit 300 feet east of this outcrop.

STOP 3. Crugers.
The purpose of this stop is to visit excellent exposures of B type Inwood and to see the Manhattan - Inwood contact.
Begin by walking down to Hudson River behind houses to sandy dolostones of Unit B. Compound folding is common here. Thin orange weathered quartzites are common in the dolostone. Rocks similar to this will be seen at Stony Point on STOP 7. Dolostones of Unit B are best exposed in the railroad cut.
Walk north to the FDR Hospital grounds and northwest along Hudson River to small point.
Here is an excellent exposure of the Inwood formation and Lower Manhattan (Oma) contact. Note the lithic characteristics diagnostic of Lower Manhattan seen on STOPS 1 and 2. A thin 2 to 3 inch coarsely crystalline calcareous marble occurs at the contact with the schist. Beneath this a zone of interlayered gray and white, crystalline, calcitic dolostone and calcite marble is exposed before massive, beige-weathered dolostones at the waters edge. Thin orange quartzites in the beige-weathered dolostones suggest this is Unit B. A thick section (200-300 ft.) of Unit C mapped to the east is not present here.
Walk east along contact. Note minor transverse faults and tectonic breccias filling fault planes (late state effects of Cortlandt intrusions, perhaps). Isoclinal F1 folds are common along the contact zone to the east.
Walk up section to foot path. Note here black and white striped calcitic schists of Manhattan Unit A. This is a very distinctive lithology seen in many places just above the base of Unit A . An excellent exposure of this can be seen at the north end of a roadcut on new Route 9 at Prickly Pear Hill (NE 1/9 Haverstraw Quad. ). Common mineral assemblages and texture in Oma at this locality are lepidoblastic muscovite and biotite (parallel to S1)-quartz-plagioclase-calcite-garnet.
Upper Manhattan is exposed above on a hill. Note change in color of the rock and in bedding characteristics. Lepidoblastic biotite and muscovite are common along with garnet, quartz, and plagioclase. Staurolite is present in some layers.

STOP 4. George's Point.
Excellent exposures of Upper Manhattan (Omb) granulites and schists. F1 folds are well exposed and dip steeply to the northeast and are mildly folded by late northeast plunging F2 folds.
This point is located between a large dioritic mass to the east and a pyroxenitic-noritic mass to the northwest (Montrose Point). The late F2 folds may be a result of shouldering aside of the country rocks by one or both plutons. These schists belonging to the Upper Manhattan will be seen at Verplanck on STOP 5 and again at Stony Point on STOP 7.
Garnet-biotite-muscovite-plagioclase-quartz is the common mineral association. No staurolite has been found here.

STOP 5. Verplanck Point Quarry (for location see Figure 1).
The contact between Unit A of the Mmhattan Formation (compare with STOPS 1, 2, and 3) and the Inwood Formation is exposed in the east wall of the quarry.
Climb over the wall carefully. a few at a time. Pelmatozoan fragments are abundant in a blue-gray crystalline limestone at the base of the Manhattan. Abundant isoclinal (F1) folding repeats this zone several times. One excellent stem plate is preserved in the crest of a small S1 isocline beneath the overhang. NO HAMMERING PLEASE! F1 axial planes strike N35°-40°E and dip 50°-60° SE. F1 plunges are moderately steep to the southwest. F2 crenulation cleavage is incipient and weakly folds the F1 axial planes. Axes of F2 plunge S25°-30° E at 45°-50°.
The intensity of F2 folds increases toward the complex.
Note the distinctly phyllitic texture of the rock. Biotite-muscovite-quartz- calcite-plagioclase-garnet is the common assemblage. Biotite usually predominates over muscovite. Both are perfectly oriented in S1 and folded by S2. An interesting bed two feet from the marble contains abundant red-brown biotite, garnet, and minor amounts of staurolite. Very distinctive green tourmaline with khaki overgrowths is an accessory mineral in most specimens of Oma here.
Walk north along rim. Excellently exposed F1 folds are shown by limy interbeds in the Lower Manhattan.
The north face of the quarry exposes white dolostone closest to the schist, assigned tentatively to Unit C of the Inwood Formation. The main layered dolostone in the quarry is characterized by dark dolostones with black phyllitic partings and thin quartzite stringers. Weathered surfaces are cream or beige. These rocks are assigned to Unit B of the Inwood Formation.
If time allows, we will walk west to the Hudson River down cliffs of sandy dolostones of Unit B to white crystalline dolostones exposed at the river's edge that probably belong to Unit A of the Inwood Formation.
A change from the staurolite-almandine subfacies of the almandine-amphibolite facies (at Verplanck quarry) to the quartz-albite-epidote-biotite subfacies of the greenschist facies (Tomkins Cove) takes place over a distance of 1.5 miles. This is a rather steep metamorphic gradient in regionally metamorphosed areas. For example, from biotite to staurolite isograds in Dutchess Co. is three miles (Balk, 1936).
Staurolite generally is ascribed to regional metamorphism because of the relatively high pressures thought to be necessary for its formation (Winkler, 1965). However, staurolite has been reported from the aureole of a shallow level granitic pluton (Rastall, 1910). Moreover, Winkler (1965, p. 109) believes staurolite with almandine might be expected in restricted areas bordering deep level plutons.
Metacrysts of staurolite and almandine in the Lower Manhattan Formation at Verplanck Point Quarry have textures indicative of post F1 crystallization and may have formed synchronous with or later than the F2 fold system. These observations are consistent with an hypothesis attributing the garnet and staurolite to contact effects induced by intrusion of the Cortlandt intrusives. Contact metamorphism under high confining pressure might be the cause of the steep metamorphic gradient seen here.
LUNCH STOP

STOP 6 (end of road). (Beware of dogs.)
Small outcrop of Upper Manhattan (Omb) - typical granulites very similar to George's Point (STOP 4). Note folded F1 folds and strong development of F2 structures. Fracture fillings in S2 probably are related to increased grade of contact metamorphism as Cortlandt intrusives are approached. Compare intensity of F2 structures with STOP 5, and note the similar orientation.

STOP 7. Tompkins Cove - Stony Point (see Figure 4 for location).
A. Railroad cut by DarkSeaGreen and Rockland plant north of quarry. Exposed on west wall is interbedded Lower Manhattan (Oma) and "crinoidal" limestone unit seen at STOP 5. Isoclinal F1 folding is common. Note refolded F1 fold and steep plunges of F1 folds.
B. Walk into main quarry. The contact of the "crinoidal" limestone unit with underlying (stratigraphically) white dolostones is exposed on the west slope of the quarry. Adventurous ones may climb up to see a truncation of S0 in the dolostone by the limestone. Is this sedimentary, or tectonic and the result of flowage? Be very careful of those following you; do not dislodge loose blocks.
From the quarry walk east to the railroad tracks and walk south toward Stony Point. Exposures of sandy dolostones, perhaps Unit B of the Inwood Formation (tops east?).
C. First outcrops are biotite diorite of the Cortlandt Complex. Climb up hill to exposure of contact with Lower Manhattan. Note discordant contact and non-foliated igneous rock and apophyses.
D. Walk south along ridge toward Cortlandtite pluton to contact with Oma. Note brecciated rock close to Cortlandtite. Fragments of foliated biotite schist float now in a matrix of K-feldspar-sillimanite-garnet and quartz. This sillimanite zone is very thin, perhaps 10 feet thick. Closest to schist is a green hornblende-rich contact phase developed around the pluton at the contact with either diorite or schist.
E. Walk down to road to west. Follow road south. Note small outcrops of limestone. Exposures of calcitic marble and Lower Manhattan (Unit B) on slopes above pond. This is metamorphosed equivalent of the crinoidal zone exposed on the west flank of the anticline. The very distinctive Oma here is a biotite-muscovite-quartz-plagioclase phyllite.
F. Continue to the south to road. Cross swamp to base of ridge to south. Exposures of carbonate rock on hillside. Probably Unit B of the Inwood Formation. Note the position south of the intrusives and its relation to STOP 3 at Crugers. The carbonate rocks close around the south side of the Cortlandt rock at Stony Point.
Walk east along carbonate outcrop to railroad tracks. Then head north along railroad toward intrusives.
G. Railroad cut in Upper Manhattan (Unit B). Shown here are dikes cross-cutting F1 and F2 folds. The contact with Cortlandtite pluton is exposed at the north end. Follow cross-section, Figure 6, for location on east wall. If a train comes, you will be warned. Please move promptly to the west side of the cut where there is plenty of room. Don't panic!
Continue north to see near vertical contact of the Cortlandtite with the schist. Note contact zone with minor drags, indicating north-up rotation sense. The hornblendite zone seen at STOP 7-D passes into typical north-dipping layered Cortlandtite 20 feet from the contact. Immediately above to the east on the slopes (see light colored soil zone) are exposures of calc-silicates of the basal Manhattan, exposed in an F1 isoclinal fold that is truncated by the Cortlandtite pluton. F2 folds are E-W perpendicular to Cortlandtite contact. The type locality of Cortlandtite (Williams, 1886) is located on the north shore of Stony Point near the swimming pier.
In the time remaining feel free to wander into the Park where there are excellent exposures of the biotite diorite with late cross-cutting lamprophyres and still later aplitic dikes. Flow structure and xenoliths can be seen in the biotite diorite. No hammering on exposed surfaces in the Park, please.
Meet bus at Stony Point Park.

I: DEEP-WELL INJECTION OF TREATED WASTE WATER--AN EXPERIMENT IN RE-USE OF GROUND-WATER IN WESTERN LONG ISLAND, N. Y.
By N. M. Perlmutter, F.J. Pearson, and G.D. Bennett
U. S. Geological Survey, Mineola and Albany, N.Y.
Publication authorized by Director, U.S. Geological Survey
Work done in cooperation with the Nassau County Department of Public Works.
No Road Log

J: GEOLOGY, GEOMORPHOLOGY, AND LATE-GLACIAL ENVIRONMENTS OF WESTERN LONG ISLAND, NEW YORK
OR
SUBURBAN PLEISTOCENE GEOLOGY: WHO BUILT A PARKWAY ON MY BOG?
By Leslie A. Sirkin, Adelphi University.
The glacial geology and geomorphology of western Long Island were first studied in detail by Woodworth (1901) and Fuller (1914). Supplementary and more recent work has been contributed by de Laguna and Perlmutter (1949), Swarzenski (1963) and Perlmutter and Geraghty (1963), among others. The reconstruction of late-Wisconsin and postglacial environments in western Long Island is based mainly on the relationships between the glacial deposits, geomorphology, and radiocarbon dated pollen stratigraphy. The pollen stratigraphy and chronology for this region (Sirkin, 1965) show consistent similarities to the late-glacial and postglacial pollen stratigraphy and chronology of southern New England (Deevey, 1958) with notable exceptions: (1) a longer and presumably more nearly complete late-glacial record is found in the vicinity of the terminal moraine (i. e., near the southern limit of late-Wisconsin glaciation), (2) deglaciation began earlier in the terminal moraine region than to the north in New York and New England, (3) the pollen record-begins with pollen spectra indicative of park-tundra vegetation, rather than the high Arctic tundra suggested in southern New England (Leopold, 1956; Ogden, 1959), and (4) the pollen zones, at least through subzone B2 (pine, oak), begin earlier in western Long Island and are time transgressive into southern New England. Finally, correlation between the pollen record, glacial geology, and geomorphology provides a means of interpreting the late-glacial physical environment.

J: GEOLOGY, GEOMORPHOLOGY, AND LATE-GLACIAL ENVIRONMENTS OF WESTERN LONG ISLAND, NEW YORK

Flushing Bay
Note crossing Flushing Bay, a glacial trough which may be linked to the Bronx River valley on the Bronx side of the East River.

STOP 1. Alley Pond Borrow Pit.
This exposure provides an opportunity to observe the lithology and structure of the Harbor Hill Moraine, (Plate 1, figure 1), the till (upper 5+ feet), the Little Neck Bay trough, and from the top of the cut, the New York skyline. Long axes of pebbles from the till point generally NNW, Note: The extension of Little Neck Bay with Eastchester Bay and the Hutchinson River in the Bronx to the north; the drumlinoid hills - Fort Totten on the west side and Douglaston on the east side of Little Neck Bay. Occassionally, the stratified drift below the till is exposed in gullies. A section is also exposed at the northeastern corner of the Korvette shopping center, below 251st st. North of the L.I.E. a small lobe projecting from the valley wall on the east side was dissected in construction. It may have been a small kame. Alley Pond bog is on top of the moraine on the west side of the valley.

LOOK STOP. Lake Success.
A kettle lake about 0.4 miles across and about 75 feet deep; several small kettles are located on the west and south sides of Lake Success.

STOP 2. Lakeville Road - Northern State Parkway.
A recent cut for widening of the parkway has exposed a section of the Harbor Hill Moraine comprised of about 5 feet of Harbor Hill till overlying 20+ feet of stratified lacustrine sands with thin clay partings (Plate 1, figures 2,3 and 4). A lake history is suggested since the results of examination for marine microfossils was negative. No other evidence for a high marine stand effecting deposition along the moraine has been found, other than the suggested wave cut cliff along the distal slope of the moraine (Woodworth, 1901). The kettle topography north and east of this site suggests that the stratified fine grained section was deposited in an ice dammed lake on the distal slope of the moraine at the junction of the outwash plain. Other large kettles developed on the pitted outwash just south of the moraine. This section is located near the junction of the Harbor Hill and Ronkonkoma moraines which may have some relationship to the stratigraphy if ice movement pivoted at this point, calving-off large ice blocks.

STOP 3. Willis Avenue - Northern State Parkway.
In this cut, northeast of the intersection, a section of 4 to 8 feet of till overlies 10+ feet of cross bedded sands and gravels and very coarse cobbles. (Plate 1, figure 5) This section is in the Ronkonkoma moraine and demonstrates the superposed till (cf.the Harbor Hill Till) over outwash and the kame like nature of the moraine.

STOP 4. Roslyn Road - Northern State Parkway.
Another cut into the Ronkonkoma Moraine, on the northeast side of the road, has exposed the lower till (cf. the Montauk Till). Approximately 10 to 15 feet of till are overlain by 25 to 30 feet of coarse cobbly, outwash (or Kame) deposits (Plate 2, figures 1 and 2). The till when exposed in a drainage trench appeared to grade downward and southward into sandy lenses.

STOP 5, Harbor Hill, Roslyn.
Harbor Hill is the type locality of the Harbor Hill Moraine and the Harbor Hill Till. The contact between the till and the outwash may be examined here (Plate 1, figure 6). The hillside just northeast of Route 25A (on the east side of the bridge) is underlain by a kame (Swarzenski, 1963). Observe the Hempstead Harbor trough and the borrow pits along the west side of the Harbor in Port Washington. Flower Hill bog is above the borrow pits and is being cut into at this

ALTERNATE STOP 6. Garvies Point.
Described at STOP 6, ahead, and in text.
The Preserve, a Nassau County facility, is set aside for archaeologic studies, and in addition to exposures of Cretaceous and Pleistocene deposits in the cliff sections, contains paleo-Indian shell middens and a possible Indian fishing site in the Cove. Typically, red, gray, and white clay with lignite lenses, marcasite nodules, and fossiliferous (plants) siderite nodules are exposed at the base of the cliffs. The plant fossils include woody fragments and leaves of fig and magnolia. Preliminary pollen and spore analysis of the clays indicates Raritan or possibly Magothy age. The clays are overlain by a white sand section and/or outwash and/or till (Harbor Hill ground moraine or recessional till) (Plat8 2, figures 3 and 4). The attitude of the slump blocks is evident here.

STOP 6. Police Rifle Range, Port Washington.
A stratigraphic section, measured in detail by students of Dr. David Krinsley, Queens College (Dr. Krinsley, personal communication) include from the base: 14 feet 2 inches of poorly sorted, pebbly, medium grained sands, 40 feet 10 inches of white sands, which are often pebbly and streaked with iron and manganese oxide stain, and about 15.5 feet of alternating light and dark sands and gravels. The age of the "white sand" layer is questionable, since it is reportedly unfossiliferous (although Dr. Walter S. Newman reports one Cretaceous spore from this horizon).
Observe Mosquito Cove - Glen Cove Creek to the ENE across the Harbor. This inlet and the low break in the cliffs north of the Rifle Range constitute a portion of the east-west drainage along the glacial stillstand referred to in the text. The Cretaceous crops out at Garvies Point on Mosquito Cove and in the Morgan Park north of that site, but it is not exposed north of the borrow pit. The cliffs to the north in Sands Point are composed of 20 to 40 feet of outwash overlain by a thin layer (5+feet) ground moraine.

STOP 7. Manhasset Valley Park - Manhasset.
At this stop, one, or possibly two, separate kames (or kame deltas) are found mantling the moraine consisting of thin till over outwash. The outwash is apparently folded or has flowed (Plate 2, figure 5) and is occasionally exposed in building excavations on Northern Boulevard (Route 25A). The till is probably recessional or ground moraine of late-Harbor Hill age. The kames exhibit striking ice contact structures (Plate 2, figure 6) and indicate a late Harbor Hill glacial advance which sent tongues of ice up the troughs. This advance is supported by several lines of evidence:
(1) the presence of kames at the valley heads.
(2) sculpturing of peripheral deposits (i.e. the drumlinoid hills) and deformation of cliff sections (although the outwash may also have been deformed during the initial Harbor Hill advance).
(3) Oscillation in the pollen record: The subzones W2 - W3 sequence indicating the stillstand and the return of cold indicators in subzone T1.
(4) the stillstand evidence including the "deltas" of Woodworth (1901) and the E-W drainage lineation (Figure 1).
Tracing the deposits clockwise around the exposure, observe the kame, next (above the wall) outwash (thin till at top) and kame (fronting on 25A behind gas station).

Note the drumlin (possible) south of lake on east side of road.

Note cuts into the moraine
Note cuts into the moraine while ascending the trough on the proximal slope of the Harbor Hill Moraine.

GUIDEBOOK
to
Field Excursions
at the
41st Annual Meeting of the
May 1969
Stockton G. Barnett, Editor
Host:
Department of Physics and Earth Sciences
State University College
Plattsburgh, New York

A: SEDIMENTARY CHARACTERISTICS AND TECTONIC DEFORMATION OF MIDDLE AND UPPER ORDOVICIAN SHALES OF NORTHWESTERN VERMONT NORTH OF MALLETTS BAY
David Hawley
Hamilton College
Clinton, New York
The central lowland of the Champlain Valley is underlain by Cambrian and Ordovician sedimentary rocks, bordered on the west by the Adirondack Mountains of Precambrian crystalline rock upon which Cambrian sandstone lies unconformably, and against which sedimentary rocks have been dropped along normal faults. The lowland is bordered on the east by low-angle thrust faults on which massive dolomite, quartzite, and limestone, as old as Lower Cambrian, from the east over-rode weaker Ordovician shale and limestone. The westernmost thrusts, the Highgate Springs thrust in the north, and the overlapping Champlain thrust in the south, trace an irregular line a few feet to 3 1/2 miles inland from the east shore of Lake Champlain. For most of the distance between Burlington and the Canadian border, the high line of bluffs marking the trace of the Champlain Thrust are composed of the massive, Lower Cambrian Dunham dolomite.
The shales, youngest rocks of the autochthonous lowland sequence, outcrop on most of the islands in Vermont, and the mainland between the thrusts and the lake. Although exposures on almost continuous shore-line bluffs are excellent, there are few outcrops inland because of glacial cover and low resistance of the shales to weathering. Fossils are rare in the older calcareous shale (Stony Point) and absent in the younger noncalcareous shale (Iberville). The lithic sequence was established almost entirely on structural criteria. Where it can be found, the Hathaway submarine slide breccia structurally over lies the Iberville

STOP 1. West shore of South Hero Island
West shore of South Hero Island, extending for one mile southward from the breakwater at Gordon Landing. The lower 215 feet of the Stony Point formation is exposed between the breakwater and the top of the Cumberland Head formation, 2900 feet to the south. In the next 2300 feet of shoreline, the upper 145 feet of the Cumberland Head formation is exposed. These sections are described in the text article. The south end of this section is cut off by a right lateral wrench fault striking N 59° W, dipping 79° NE. South of the fault the interbedded limestone and shale (about 79% ls., 30% sh.) have been mapped as the Shoreham member of the Glens Falls formation (Erwin, 1957) on the basis of lithology and the presence of Cryptolithus.

STOP 2. Road cut on east side of U.S. 2
Road cut on east side of U.S. 2 halfway between City Bay (North Hero Beach roadside park) and Carrying Place. This outcrop shows the interbedded laminated argillaceous limestone and calcareous shale typical of the middle section of the Stony Point formation. It lies close to the axis of a major, northeastward plunging anticline.

STOP 3. Middle point on north side of Carry Bay
Middle point on north side of Carry Bay, North Hero, 2000 feet east of Blockhouse Point. Typical Iberville cyclic bedding is exposed for about 1500 feet along this shore, extending eastward from the place where the access road meets the shore. From west to east are: an asymmetrical syncline, an asymmetrical anticline, and to the east of a covered interval is the east, overturned limb of a large syncline. These folds are in the axial area of a large, northeastward plunging, overturned syncline. Relationships of cleavage to bedding, axial surfaces, and direction of plunge are well shown. Small-scale current cross-lamination on some beds indicates southwestward flow.

STOP 4. Quarry in Iberville
Quarry in Iberville (mislabelled "gravel pit" on No. Hero Quad. map), 1.6 miles S 10° E from east end of North Hero-Alburg bridge. The beds are almost flat-lying, and only about 15 feet of section is exposed, but it is typical cyclic deposition, and the details are well shown, as described in the text.

STOP 5. Unnamed promontory
Unnamed promontory 1300 feet WNW of Coon Point, south Alburg. Upper-middle Stony Point beds measuring 258 feet (Hawley, 1957, p. 60, 89-91), with the base of the section on the southern tip of the point. It is composed of: olive-gray weathering, dark-gray argillaceous limestone, frequently silty, with light olive-gray weathering bands and laminae, in units of 3 inches to 40 feet, making up 96 percent of the section; light olive-gray weathering, dark-gray fine-grained limestone in beds of half an inch to 12 inches, making up 4% of the section. There are four thin (1/4 inch to 1 1/4 inch) beds of medium light-gray weathering, medium gray fine-grained crystalline limestone. Pyrite concretions are common. Trilobites (Triarthrus becki) are fairly common on a few bedding surfaces, and a few unidentifiable graptolite fragments were found. This stop is relatively inaccessible, may be cut off by high water, and may have to be omitted.

STOP 6. A small quarry, 3.3 miles north of Alburg - North Hero bridge
A small quarry, 3.3 miles north of Alburg - North Hero bridge on the west side of highway U.S. 2. Stony Point argillaceous limestone-rich section as described for Stop 5, including a fair scattering of Triarthrus becki.

STOP 7. Upper Iberville beds on the south and west sides of Clark Point
Upper Iberville beds on the south and west sides of Clark Point, at the south end of Hog Island (Vt. Hwy. 78 crosses Hog Island), west Swanton. A 304-foot section has been measured here (Hawley, 1957, p. 91-92). It is 97.8 per cent thin-cleaving noncalcareous shale (1 to 3 inch beds) with thin laminated dolomitic siltstone (1/4 inch to 2 inch beds, occasionally thicker) and homogeneous fine-grained dark gray dolomite, weathering yellowish-brown, in beds up to 14 inches, at intervals of 3 to 50 feet. Cyclic deposition is prominent here, with an estimated 1215 cycles in this section. The thin dolomitic siltstone beds commonly show cross-lamination and ripple drift, with southwestward currents indicated.

STOP 8. Upper Iberville beds in quarry
Upper Iberville beds in quarry (mislabelled "sand and gravel pit" on East Alburg Quad. map) 1800 feet north of Vt. Hwy 78 and 600 feet west of Campbell Road, northern Hog Island, west Swanton. The rock is similar to that described for Stop 7. The quarry exposes an overturned anticline, thrust faulted on the upper, eastern limb, with adjacent syncline immediately westward, also faulted.

STOP 9. Southernmost tip of St. Albans Point
Southernmost tip of St. Albans Point, on property of Camp Kill Kare. Northeastward plunging asymmetrical anticline with linked small syncline northwest of it, in Iberville noncalcareous and calcareous shale with dolomitic interbeds.

STOP 10. Between Camp Kill Kare's access road and the lake
Between Camp Kill Kare's access road and the lake, about halfway between the private cottages and the Camp buildings. There are 31 feet of white weathering, grayish-black chert in beds of 2 to 6 inches, dipping steeply (69° ) southeastward on the southeast flank of the anticline at Stop 9. Structurally overlying the chert beds is black siliceous argillite in which bedding is not apparent because of its irregular, chippy foliation. The argillite contains rounded pebbles (avg. 1 by 2 inches) of gray dolomite and fragments of chert. Some graptolites were found in the argillite, but smearing precluded identification. This is part of the Hathaway formation. It is likely that the chert beds here represents a larger mass involved in a submarine slide.

STOP 11. Hathaway Point, at the south end of St. Albans Point.
This is the type locality for the Hathaway formation. It has a matrix of pale-greenish-yellow weathering rock seen on a polished surface to be composed of small, irregular, curdled masses of greenish-gray to olive-gray argillite. Streamed and isoclinally folded in the matrix is black siliceous argillite similar to that associated with the chert beds at Stop 10. "Floating" in the matrix are small masses of grayish-black radiolarian chert which are commonly angular, as well as masses of bedded chert measurable in tens of feet. Fragments of dolomite and dolomitic siltstone occur in the western part of the Hathaway point exposure. Numerous slickensided tectonic shears are present in a variety of orientations. One 40-foot wedge between shears is composed of isoclinally folded calcareous and noncalcareous shale with occasional boudinaged masses of fine-grained limestone, resembling the transition beds at the base of the Iberville. Both of the islands east of Hathaway Point, in the middle of the bay, are composed of chaotically deformed argillite and chert. It is assumed that St. Albans Bay may lie over a deep synclinorium.

STOP 12. Lime Rock Point, on the southeast side of St. Albans Bay.
At the base of the bluff composed of the Beldens (Upper Canadian) crystalline limestone with buff-weathering dolomitic beds, there is a dramatic exposure of the Highgate Springs overthrust; lower Ordovician Beldens Limestone over upper Ordovician Iberville calcareous and noncalcareous shale with occasional beds of yellowish-brown weathering fine-grained dolomite and silty dolomite. At the base of the high, steep bluff about one half mile to the east is the Champlain overthrust, on which the lower Cambrian Dunham dolomite is thrust westward over the Beldens. South of Lime Rock Point the Highgate Springs thrust slice is overlapped by the Champlain thrust for two and a half miles. It reappears for four miles, and then disappears again under the Champlain thrust, southeast of Beans Point. This is as far south as the Highgate Springs slice can be traced.

STOP 13. Beans Point, east shore of lake in northwest Milton.
The Hathaway crops out intermittently for 1200 feet north from Beans Point. This is in a zone of intense deformation close to the Highgate Springs thrust, the trace of which is covered, probably about 600 feet back from the shore. The base of the steep bluffs 2000 feet back from the shore marks the trace of the Champlain fault, on which lower Cambrian Dunham dolomite has been thrust over Beldens crystalline limestone and dolomite of the Highgate Springs slice.
The Hathaway is composed of boulders and fragments "floating" in mashed argillite. The argillite is mottled olive gray to dark greenish gray to greenish black. On a polished surface cut perpendicular to foliation the mottled colors are seen to represent original bedding which has been folded most intricately, and sheared with no development of slickensides or breccia. The small-scale shearing has completely healed, and some minute fold crests merge into the adjacent bed, a streaming of one bed into the next with no sharp boundary. Included in the argillite are rounded fragments of moderate-yellowish-brown weathering, dark gray fine-grained dolomite and cross-laminated dolomitic siltstone, sub-angular to rounded, up to 4 by 7 by 20 inches in size. The long axes of the boulders are approximately parallel, plunging about 55° toward S 45° E. Foliation causes the argillite to split into irregular tapered chips. Thirty-six feet of cover separates the north end of the Hathaway outcrop from cyclic-bedded upper Iberville which lies overturned, dipping 46° northeastward.

STOP 14. Camp Watson Point, 3/4 mile south of Beans Point (Stop 13).
The core of a large, overturned syncline is exposed on the point, plunging 18° toward N 56° E. The overturned limb, dipping 29° southeastward, is exposed for 200 feet or more along the shore to the south. The rock is lower Iberville transition, with interbedded calcareous and noncalcareous shale, argillaceous limestone, and silty laminated dolomite.

STOP 15. Clay Point, between Malletts Bay and the Lamoille River
Clay Point, between Malletts Bay and the Lamoille River, east shore of lake. THIS PROPERTY IS POSTED, AND PERMISSION MUST BE OBTAINED. In the transition beds in the lower Iberville (interbedded calcareous and noncalcareous shale, with argillaceous limestone, argillaceous dolomite, fine-grained dolomite, and silty-laminated dolomite with current crossbedding) there is a small, overturned anticline cut by small thrust faults. The relationship of cleavage to bedding, plunge of the fold, identification of tops by cross-bedding, and the faulting make this a worthwhile stop for a structural geology class.

STOP 16. From Kibhee Point southeastward along the shore
From Kibhee Point (northeastern South Hero) southeastward along the shore for 2500 feet, is exposed the transition from Stony Point to Iberville formations. With a few minor rumples the dip is southeastward all the way to a deep gully and small bay which separate a steep bluff-point to the east from the shore northwestward to Kibbee Point. This bluff, 2800 feet SE of Kibbee Point is composed of Stony Point argillaceous limestone and calcareous shale, overturned and dipping 55° southeastward. Thus, the gully conceals the faulted core of an overturned syncline. The fault is very likely a thrust, east side up.
West of the gully is Iberville, about 90% finely cleaved noncalcareous shale, with interbedded silty cross-laminated dolomite. Northwest from here to Kibbee Point the proportion of noncalcareous shale and silty laminated dolomitic interbeds decrease and the proportion of calcareous shale increases. About 220 feet southeast of Kibbee Point the southeastward-dipping beds are massive calcareous shale (Stony Point fm.). About 900 feet south of Kibbee Point on its west shore the Stony Point beds still lower in the section are predominantly argillaceous limestone, interbedded with calcareous shale.

B: RECENT SEDIMENTATION AND WATER PROPERTIES, LAKE CHAMPLAIN
Allen S. Hunt and E. B. Henson
University of Vermont
Purpose
Within the last few years a considerable amount of research has been done on Lake Champlain. The purpose of this trip is to show what type of work is being carried out on the lake and to report some of the findings.

STOP 1. First stop of west-east traverse
This stop, along with stops 2 and 3, will constitute a west-east traverse designed to show differences in thermal patterns, benthos, and sediment types across the lake. At stop 1, a bathythermogram will be taken to demonstrate water temperature differences with depth. A grab sample will be taken and sieved for macro-organisms, and a core sample will be collected. The sediments at this stop are organic muds which contain no gravel, less than 10 percent sand, and equal amounts of silt and clay. The mean phi size is about 8, the standard deviation 2.5 phi.

STOP 2. Middle stop of west-east traverse
A bathythermogram and core will be taken and a grab sample will be sieved for benthos. The sediment at this stop is described under "sediment properties" as a pebbly sandy clay. An average sample contains 25 percent sand and gravel, 10 percent silt, and 65 percent clay. The mean grain size is 8 phi, the standard deviation 4.5 phi.

STOP 3. Last stop of west-east traverse
A bathythermogram will be taken at this station to complete the traverse profile, the benthos will be sampled, and a plankton haul will be made. Water samples will be taken from selected depths and analyzed for alkalinity, pH, and dissolved oxygen. The sediments at this stop consist of organic muds. The mean grain size is 8 phi, and the standard deviation just over 2 phi. Sand makes up less than 5 percent of the sample with silt and clay equally divided among the remaining portion.

STOP 4. This is a shallow-water stop at the mouth of the Winooski delta.
Grain-size analysis has shown sediments to be about 90 percent sand, 10 percent silt, and 1 percent clay. The mean grain size is 2 phi, the standard deviation just over 1 phi. Note the absence of an interface on the sediment surface.

STOP 5. This stop is to collect sandy clay sediment.
The sandy clays have much in common with the pebbly sandy clays of stop 2 in that both are poorly sorted, and both have a high percent of sand and clay with only a small percentage of silt. The pebbly sandy clay and the sandy clay may be facies of the same sediment.

C: BEDROCK GEOLOGY OF THE SOUTHERN PORTION OF THE HINESBURG SYNCLINORIUM
Rolfe S. Stanley
University of Vermont
Purpose
The geology of west-central Vermont has attracted the attention of geologists since the early work of Hitchcock, et al. (1861), and Logan (1863), to mention only two. During this century notable contributions have been made by Perkins (1910), Keith (1923, 1932, 1933) and, in particular, Cady (1945, 1960). The mapping of Welby (1961) west of the Champlain thrust, and Stone and Dennis (1964) in the Milton quadrangle just north of Burlington, completes the present state of knowledge of the Hinesburg synclinorium and immediate surrounding areas (Fig. 1, inset map). These works are incorporated in the Centennial Geologic Map of Vermont (Doll, et al., 1961).
Among several major problems still remaining to be resolved is a clearer understanding of the effects of the Acadian and subsequent orogenies or disturbances on the structures of west-central Vermont. Inasmuch as rocks of Upper Ordovician through Devonian age are not present in western Vermont, it becomes most difficult to evaluate the relative importance of Taconic and younger events. Answers to this central problem with its many corollaries can hopefully be provided by detailed studies involving a combination of stratigraphic, petrologic, geochronometric, and structural approaches. It is the purpose of this trip to examine the geology of the Hinesburg synclinorium and to show how recent work may be helpful in answering these problems in the future.

STOP 1. Champlain thrust at Long Rock Point, Burlington
(Note: The Episcopal Diocesan Center has been kind enough to allow us to visit this locality. Please do not litter.) This locality is perhaps one of the finest exposures of the Champlain thrust in Vermont and Canada. Here the Dunham Dolomite (Conners facies) of Lower Cambrian age overlies the Iberville Formation of Middle Ordovician age. The thrust contact is sharp and marked by a thin discontinuous zone of breccia in which angular clasts of dolostone are embedded in a highly contorted matrix of shale. Slivers, several feet thick, of limestone are found along the fault and may represent pieces of the Beekmantown Group (Beldens Member of the Chipman Formation?). The undersurface of the Dunham Dolomite along the thrust is grooved by fault mullions which plunge 15° to the southeast (Fig. 3 diagram 1 and 2a). The average southeastward dip of the thrust is 10°.
A variety of minor structures are found in the Iberville Formation whereas joints are the only structures in the Dunham Dolomite. Faults and joints are oriented in a number of attitudes in the shale, but they have not been analyzed as yet. Many of these fractures are filled with calcite and grooved with slickensides. The minor folds in the shale are numerous, and are easily grouped into two age generations. The early folds have a well developed slaty cleavage which offsets the bedding and attests to differential flow parallel to the axial surface. Although only a few fold hinges are present, the slaty cleavage forms the dominant layering and is concordant to the undersurface of the Dunham Dolomite.
The younger generation consists of asymmetrical drag folds with short gently curved hinges and rather open profiles. The axial surface is rarely marked by cleavage but when it is developed, fracture cleavage, which is commonly filled with calcite, is typical. These folds deform the slaty cleavage of the older generation and hence are younger in age. The orientation of 59 axes with their sense of rotation is shown in diagrams 1, 2a and 2b of figure 3.
Slip line orientations The drag folds of the younger generation can be used to determine a slip surface and direction according to the method described by Hansen (1967, p. 390-397). The analysis assumes that these folds are in the truest sense drag folds and have formed by movement of one layer or zone over another. In this locality the drag folds in the shale presumably were formed by Dunham Dolomite moving over the Iberville Formation. Because the shale is highly anisotropic, consisting of thin layers of compact shale separated by thinner layers of extremely fissile shale, the folds are confined to zones several feet in thickness and are disharmonic in profile.
A slip plane and line were determined for three separate localities at Rock Point (Fig. 3, diagrams 1, 2a, 2b). For each place the 18 to 23 fold axes with their respective senses of rotation were plotted on a lower hemisphere equal area net. The great circle that best approximates the spatial distribution of axes defines the slip plane. In all the diagrams of figure 3, clockwise folds cluster along one part of the slip plane whereas counterclockwise folds cluster along the other. The bisector of the arc separating the two groups of folds is the slip line. The location of clockwise and counterclockwise arrows on either side of the separation arc determines whether the upper layers moved up or down along the slip line. In diagrams 2a and 2b (Fig. 3) the upper layers moved to the northwest along a line striking N 40 W for 2a, and N 54 W for 2b. In contrast the upper layers moved downward along a line striking N 86 E for the southern part of the Champlain thrust at Long Rock Point. (diagram 1, Fig. 3).
Discussion of Results The kinematic basis for this analysis has been worked out in such geologic environments as tundra and sod slides, glacial lake clays, lava flows and metamorphic rocks of all grades (Hansen, 1967; Hansen, et. al., 1967; Howard, 1968). It can be shown that the separation arc contains the movement direction of slip line and that the drag folds which locate this direction are a product of one movement event. One can further deduce the likely position of the principal axes of stress (σ1,σ2, σ3 by analogy to slip systems. σ2 would lie in the slip plane perpendicular to the slip direction. σ1 and σ3 would define the deformation plane which is perpendicular to the slip plane and parallels the slip direction.
σ1would be oriented approximately 45° from the slip plane in a direction permitted by the sense of shear indicated by the drag folds. The slip line would then parallel the direction of maximum resolved shear stress.
In all subsequent discussions σ1 is the maximum compressive stress, σ2 is the intermediate compressive stress and σ3 is the minimum compressive stress.
Diagrams 1 through 3 (Fig. 3) were determined at localities in the Iberville Formation beneath or just west of the Champlain thrust. With the exception of diagram 1, the slip directions indicate movement to the northwest (see diagram 7, Fig. 3 for synopsis). This direction is approximately parallel to fault mullions at Long Rock Point and slickensides on calcite-veneered surfaces at Shelburne Point (diagram 3) and, therefore, suggests that the deformation plane containing σ1 and σ3 for this phase of movement did trend northwesterly. A unique explanation for the easterly slip direction in diagram 1 is not known at present, but several possibilities will be discussed.

STOP 2. Shelburne Access Area
This locality is one of several places in the Monkton Quartzite that displays a sufficient number of joints, faults and feather joints for dynamic analysis. The location and orientation of faults and feather joints are shown on the geologic map (Fig. 4). At each numbered station the orientation, relative abundance, and surface features of approximately 10 joints were recorded. Diagram A of figure 5 shows the poles to 248 joints and diagram B shows four planes corresponding to the maxima in diagram A. The trend of each of the 10 feather joint arrays and their sense of shear are shown in diagram C.
Diagram D shows 13 faults with letters or arrows indicating the apparent movement. All faults trend approximately eastward (hereafter called cross faults) except for one that is striking to the north. As indicated on the map the dip slip displacement of each fault is only several inches whereas the strike slip displacement on one of these faults is 9 feet (fault 13, Fig. 4). (Faults are identified by the station number nearest them on the geologic map (Fig. 4)). Feather joint arrays adjacent to several cross faults further attest to strike slip displacement. This relationship is further emphasized by comparing diagram C and D (Fig. 5). Although Welby (1961, p. 204) assumes that all cross faults are normal faults, the above data definitely supports a wrench fault interpretation. Petrofabric analysis of quartz deformation lamellae in three samples (Ml, M3, M4) further confirms this conclusion (Fig. 6).
Dynamic Analysis Discussion of the stress configurations for each structure is based upon techniques and principles summarized by Friedman (1964). In stress analysis only the direction and relative magnitudes of the principal stresses can be evaluated. Furthermore, it is assumed that the manner in which these structures formed in nature is similar to the way analogous structures are formed in the laboratory.
Joints: The planes in diagram B (Fig. 5) corresponding to the maxima of diagram A can be interpreted in several ways. The acute angle between joints 1 and 3 is 80 degrees and the acute angle between joints 2 and 4 is 83 degrees.
Hypothesis 1: Joints 2 and 4 formed in the shear position. Joints 1 and 3 formed as extension and release joints respectively.
Hypothesis 2: Joints 1 and 3 formed in the shear position. Joints 4 and 2 formed as extension and release joints respectively. In both hypotheses σ2 is defined by the intersection of all joints. In hypothesis 1, σ1 would parallel joint 1 and trend to the east whereas in hypothesis 2 0σ1 would parallel joint 4 and trend to the southeast. Hypothesis 1 is preferred because joint 1 is commonly filled with calcite. Furthermore, this configuration is similar to the stress configurations deduced from the other structures (Fig. 6).
Feather joints: The 10 feather joint arrays in diagram C (Fig. 5) with their respective senses of shear indicate that σ1 is oriented east-west. σ3 is oriented north-south and σ2 is oriented vertically. Because the dip of the feather joint array could not be measured, the inclination of the principal stress axes could not be pinpointed. Although the principal stress directions are not as accurately known for feather joints as they are for other structures, their symmetrical relationship to the cross faults support a wrench fault interpretation and thus suggest that those faults trending north of west are left lateral whereas those trending north of east are right lateral.
Wrench Faults: The apparent vertical movement on all faults trending north of west is up to the north. This movement can be realized on left lateral wrench faults if σ1 dips more steeply to the east than the bedding. Those faults trending north of east that are downthrown to the north would then be right lateral wrench faults.
The apparent vertical movement of faults 4 and 13 trending north of east is up to the north. These faults are right lateral wrench faults if the movement on 4 is assumed to be the same as the displacement of fault 12 by 13. The horizontal and vertical components of the actual movement at these faults could be caused by σ1 trending westward and dipping eastward more gently than the bedding.
North-South Fault: This fault cuts several of the wrench faults and hence is younger in age. It could result from the following two stress configurations: Hypothesis 1: If the fault is a normal fault downthrown to the west, then σ1 would be vertical or steeply inclined to the north so as to produce the right lateral movement. σ3 would trend eastward or dip gently westward. σ2 would trend northward.
Hypothesis 2: If the fault is a wrench fault, then σ1 would trend northeasterly. σ3 would trend northwesterly and σ2 would be approximately vertical.
Quartz Deformation Lamellae: Approximately 380 deformation lamellae from 3 oriented samples have been measured from this outcrop. For each sample 100 (50 for M4) quartz grains were measured from each of three mutual perpendicular thin sections. For each grain the orientations of the c axis and deformation lamellae (if present) were measured. The results were analyzed using methods described by Carter and Friedman (1965), and Scott, et al., (1965). The deduced orientation for σ1,σ2, and σ3 are shown in figure 6. In M3 and M4, 01 lies in the bedding and 02 appears to be equal to 03 in magnitude. In Ml σ1 is inclined 40° to the east, σ2 dips 50° to the west and σ3 trends northward and is horizontal. Although these orientations are not parallel in all samples, they are consistent with the stress positions deduced from the megascopic structures and support the conclusions on the cross faults and joints.
Structural and Stress History Based on the above information it is possible to develop a structural history for this outcrop. This sequence is divided into the following three phases.
Phase 1: During this time all the wrench faults formed except fault 13, 4 and 10 (north-south fault), σ1 was inclined more steeply to the east than the bedding so that faults trending north of west are upthrown to the north and faults trending north of east are downthrown to the north. σ3 was oriented northward and σ2 was inclined steeply to the west.
Phase 2: During this time faults 13 and 4 developed with σ1 either horizontal or inclined more gently eastward than the bedding. This orientation permitted the right lateral faults (13 and 4) to be upthrown to the north. It should be emphasized at this point that the change in orientation of σ1 relative to the bedding in the Monkton Quartzite can equally be attributed to a rotation of the bedding within a stress system of constant principal stress orientation.
Phase 3: During this time the north-trending fault developed and can be interpreted as a normal, wrench, or reverse fault.
The feather joints and deformation lamellae are thought to have formed during phase 1 and 2, although definite evidence for their timing is lacking at present. The formation of the joints shown in diagram A and B in figure 5 could well have spanned the first two phases.
Relationship to the Champlain Thrust Wrench faults are commonly associated with thrust faults. Both can be related to the same σ1 direction and only require a switch of σ2 and 0σ3 in the stress configuration during thrusting to develop wrench or tear faults. In the same manner the small wrench faults in the Monkton Quartzite are thought to bear the same relationship to the Champlain thrust and as such suggests that other cross faults shown on the Geologic Map of Vermont (Doll, et al., 1961), may also be wrench faults.
The different stress orientations deduced at Long Rock Point (stop 1) and the Shelburne access area suggest several explanations. It is possible that they formed under the same stress system but have assumed their present orientation by subsequent deformation. Alternatively, they could have formed at different times under stress systems of different orientations. Future work will resolve this problem.

STOP 3. Winooski Dolomite in fault contact with Monkton Quartzite
This locality is a fine exposure of the Winooski Dolomite in fault contact with the upper portion of the Monkton Quartzite. The bedding in both these units dips gently eastward. The most conspicuous of several northeastward-trending faults is downthrown to the north placing the Winooski Dolomite in fault contact with the upper portion of the Monkton Quartzite south of the fault.

STOP 4. Shelburne Falls just southeast of the village of Shelburne
The Danby Formation dips gently eastward at this locality and is cut by several sets of joints. Ripple marks of varying sizes, cross beds and fossil burrows are well displayed in the quartzite and sandy dolomite on the west bank of the river. Current directions based on current ripples in the upper layers along the southern part of the exposure indicate flow to the southeast (S 10 E to S 40 E) whereas current directions based on cross bedding in the lower layers exposed near the falls to the north indicate flow to the north and west.

STOP 5. Jones Hill
This stop is located just west of the Champlain thrust and shows several large folds and minor thrusts exposed in the Iberville Formation. A lamprophyre dike, striking N 78 W and dipping 75 degrees to the northeast, is exposed in the southern part of the outcrop. The laccolith of syenite on Barber Hill is located approximately a mile southeast of here near the village of Charlotte.
The orientation of fold axes, slaty cleavage and faults is shown on figure 7; most of the faults are thrusts dipping eastward or southeastward at gentle to moderate angles. As shown on plate 1 the trace of the Champlain thrust is sinuous and offset at several places in the area. Welby (1961, Plate la) shows normal faults at each of these places but the orientation of bedding, particularly between Jones Hill and Pease Mountain, suggests that the eastward reentrants can be explained equally well by anticlines plunging gently to the east. Minor folds with this orientation are present on the north side of Jones Hill.

STOP 6. A short traverse through the fields north of the road.
This stop will consist of a short traverse through the fields north of the road. The Clarendon Springs Dolomite, the Shelburne Formation, and the Cutting Dolomite will be crossed. If time permits the traverse will be extended northward into the Bascom Formation. At least two generations of folds are present in this area. Axes of the earlier generation plunge to the southeast, east and northeast and possess a well developed axial surface cleavage which commonly dips eastward except when it is deformed by folds of the younger generation. The slip line orientations of diagrams 4 and 5 (Fig. 3) were determined from drag folds of the earlier fold generation at localities 4 and 5 on figure 1. These slip lines are almost parallel to those to the west of the Champlain thrust discussed under stop 1 and, therefore, strongly suggest that they may have formed contemporaneously as a result of the same stress system. The younger generation of folds plunges northward and folds the cleavage of the earlier fold generation.

STOP 7. Hinesburg thrust northwest of Mechanicsville
This locality is one of the finest exposures of the Hinesburg thrust. The Bascom Formation forms the lower plate and the argillaceous facies of the Cheshire Quartzite forms the upper plate. Minor folds can be found in both these units. Inasmuch as only 4 folds could be found in the Bascom Formation little significance can be attached to southwestward movement direction shown in diagram 6 (Fig. 3).

STOP 8. The Bascom Formation
The Bascom Formation crops out on several small hills just west of Brownell Mountain. To the east the Bascom grades into the Brownell Mountain Phyllite, a member of the Bascom Formation only recognized in the Hinesburg synclinorium. This stop may be cancelled if insufficient time is available.

D: THE LATE PLEISTOCENE OF THE CHAMPLAIN VALLEY, VERMONT
W. Philip Wagner
University of Vermont
Burlington, Vermont
The existing knowledge of Pleistocene events in the Champlain Valley can be discussed in terms of glacial stratigraphy, areal distribution of glacial deposits, and water planes of Lakes Vermont and "New York", (this paper) and the Champlain Sea. The purpose of this field trip is to examine new evidence of glacial and post-glacial events as recently deduced from field study of the Champlain Valley between Burlington and Middlebury, Vermont.
Included in the list of references are recent papers which pertain to the Pleistocene and Recent history of the Champlain Valley. The topographic quadrangles, in order of their first appearance on the field trip, are as follows: Burlington; Fort Ethan Allen; Essex Junction; Mount Philo; Hinesburg; Bristol; Monkton. Acknowledgement is made to Chester A. Howard, Jr. and William R. Parrott, Jr. for data on Stop 16, to Howard for information about surficial deposits near the mountains north of the Winooski River (Fig. 1), to Robert Switzer for field assistance in 1967 and 1968, and to Allen S. Hunt for a review of the manuscript. The work upon which this paper is based was supported in part by funds provided by the U. S. Department of Interior as authorized under the Water Resources Research Act of 1964, Public Law 88- 379.

STOP 1. Champlain Sea beach (No.1, Figs. 1 and 2)
Exposures in gravel pits on both sides of barn show excellent beach structures and marine mollusks.

STOP 2. Lake New York beach-spit and delta (No.2, Figs. 1 and 2)
Gravel pits are in beach material; slightly lower bench to west is composed of deltaic sand which correlates with No.4, Figures 1 and 2.

STOP 3. Lake New York beach (No. 56)
One of the best developed beach landforms known in the area; terrain immediately east of beach is lake clay and west of beach is a lower level Lake New York delta. Note dunic(?) landforms between stops 3 and 4.

STOP 4. Fort Ann delta (correlative with No. 57)
Gravel pit shows channel structures characteristic of deltas in this area.

STOP 5. Oak Hill outlet channel (No. 68)
Gravel pit in channel bottom shows very coarse, poorly sorted gravel; outlet drained a Winooski Valley Lake in post-Coveville (?) time and therefore proves (?) that ice blocked the Winooski Valley during Coveville time.

STOP 6. Ice-contact delta (No. 59)
Numerous gravel pits in vicinity show progressively finer material from stop 5 to stop 6 where cross-bedded fine gravel, sand, and silt are exposed in pit; ice-contact nature of delta is suggested by poorly sorted gravel in nearby vegetated area to southwest; delta was apparently formed by Oak Hill channel water drainage into local lake impounded by continental ice.

STOP 7. Fort Ann bench (No. 27)
Road cut exposes coarse, poorly sorted gravel underlying (?) boulder-strewn (lag?) bench on hillside. A problem exists here in that the topography and the lag (?) suggest an erosional environment whereas the road cut indicates a depositional environment. Possibly mantle material (see text) has been modified by wave action.

STOP 8. Hummocky dead ice terrain (No. 43)
Stop is at gravel pit showing poorly sorted character of deposit; ice contact structures are visible in places in the vicinity from time to time.

STOP 9. Ice-contact delta?
This is a brief photography stop. Large scale cross-bedding is in kame terrace, delta, or ice-contact delta(?). The last named possibility is favored here.

STOP 10. Kame terrace
Gravel pits in vicinity show characteristic ice-contact features.

STOP 11. Pre-Coveville (44, 45), Coveville (46), and upper Fort Ann (47) delta
STOP 11. Pre-Coveville (Nos. 44 and 45), Coveville (No. 46), and upper Fort Ann (No. 47) deltas; 3 miles southeast of Hinesburg along Route 116; deltas were constructed by water from a local Winooski Valley lake which drained through an outlet channel (No. 67) at the divide between Hollow Brook and Huntington River; gravel pits show coarse gravel with large scale foreset bedding and less obvious topset bedding in places.

STOP 12. Coveville (No. 50) and upper Fort Ann (No. 51) deltas
The village of Bristol is located on the Coveville delta and the upper Fort Ann delta just west of Bristol; gravel pits show features similar to those at stop 11.

STOP 13. Lacustrine sediment veneered hummocky dead ice terrain; No. 53
Gravel pit exposes ice-contact material overlain by and interbedded (?) with lacustrine sediment; features suggest glacial and lacustrine sedimentation in close proximity.

STOP 14. Shoreline features of Lakes Fort Ann and New York (Nos. 16-22)
Southwest side of Mount Philo; a spectacular succession of six wave-cut benches and one beach-spit.

STOP 15. Two(?) till locality
Stewart (1961a, Stop 6) reports two till units with intervening lake sediment. The present investigation showed complex vertical and horizontal variations. At the east end of the exposure occurs (bottom to top): gray till (25 feet); till or gravel (30 feet); slumped lake clays. At the west end: gray till (25 feet); lake sediment (25 feet). At the middle of the exposure as many as five till units with intervening lake sediment have been counted. Lateral relationships are difficult to determine due to the steepness of the exposure but facies changes are likely.

STOP 16. Two(?) till locality
Stream bank exposures of a lower gray till and upper brown till; Stewart's (1961a, Stop 4) type locality for the Shelburne (gray) and Burlington (brown) tills. At the time of this writing, fabric and clay mineralogy analyses are being made. This information will hopefully be available for field trip presentation.

E: STRATIGRAPHY OF THE CHAZY GROUP (MIDDLE ORDOVICIAN) IN THE NORTHERN CHAMPLAIN VALLEY
Frederick C. Shaw
Herbert H. Lehman College
Bronx, New York
The Chazy Limestone (the oldest Middle Ordovician Group of the Champlain Valley) was first named by Emmons (1842) from exposures 15 miles north of Plattsburgh at Chazy, New York. Here and elsewhere in the northern Champlain Valley (Fig. 1) the unit outcrops on a variety of normal fault blocks. Given the low dips and heavy cover, Chazy stratigraphy is most easily understood from various shore outcrops around Lake Champlain. Valcour Island, southeast of Plattsburgh, offers perhaps the best section of the Chazy, and has been intensively studied (Raymond, 1905; Hudson, 1931; Oxley and Kay, 1959; Fisher, 1968; Shaw, 1968). The Isle La Motte, Vermont, exposures to be covered in this trip and trip Fare those studied by many of the same authors and, in addition, display the lower contact of the Chazy with the underlying Ordovician dolostones of Canadian age.
In the northern Champlain Valley (Valcour Island and north to the International Boundary), the Chazy Limestone (now Group) consists of about 800 feet of quartz sandstones, calcarenites, dolomitic calcilutites and biohermal masses (Fig. 2). Three formations, Day Point, Crown Point, and Valcour, in ascending order, were proposed by Cushing (1905) and have persisted to the present, albeit with some controversy (Fisher, 1968; Shaw, 1968). Oxley and Kay (1959) further subdivided the Day Point and Valcour into members, those of the Day Point (Head, Scott, Wait, Fleury) coming from southern Isle La Motte in the area to be visited. Shaw and Fisher experienced difficulty in using the Valcour subdivisions outside of their type areas at South Hero, Vermont.

STOP 1. The Head, Isle La Motte, Vermont
PLEASE NOTE: STOPS 1 AND 2 ARE ON PRIVATE PROPERTY WHICH WE HAVE SPECIAL PERMISSION TO ENTER. DO NOT SMOKE IN THE FIELDS, KNOCK OVER FENCES, ETC. OTHERS MAY WANT TO RETURN TO THIS CLASSIC LOCALITY AFTER YOU.
Lakeshore outcrops of the Providence Island Dolostone (Lower Ordovician) and the Day Point Formation (Chazy Group). Dip of both units several degrees to the north. Contact well-exposed and at least locally unconformable. Locality discussed by Shaw (1968), Erwin (1957). Section measured and described by Oxley and Kay (1959).
Approximately 40 feet of Providence Island Dolostone is exposed, being very fine-grained, massive, thinly laminated, am unfossiliferous. Mudcracks and a few ripple marks complete the picture of a unit deposited in very shallow water. Following Laporte (1967), the environment of formation was probably supratidal, closely paralleling modern day environments of dolomite formation described from Florida and the Bahamas. No detailed petrologic work has been done on this unit. In the absence of fossils, the age of this unit is not known. The underlying Fort Cassin Limestone (not exposed here) is known to be Late Canadian.
The Chazy Group begins here with about 20 feet of quartz sand and siltstones together with minor amounts of greenish shale (Head Member of Oxley and Kay, 1959). Ripple marks and cross-bedding are common. The fossils consist primarily of 'fucoids' (probably recording a variety of trails, worm tubes and the like) and Lingula. The succeeding Chazy unit (Scott Member of Oxley and Kay) consists of about 40 feet of echinodermal lime sand, cross-bedded in some places. Brachiopods (Orthambonites?) and indeterminable trilobite scraps are the chief recognizable fossils. The overlying 15 feet of quartz sandstone (Wait Member of Oxley and Kay) appears very similar to the initial sandstone.
This second sandstone is followed by a thick (115 feet) lime sand (Fleury Member of Oxley and Kay) which occupies most of Scott Point and The Head south of the road. Much of the unit is composed of echinoderm fragments, although little is known about the actual morphology of the creatures involved. Both the fragmental nature of the fossils and the frequently observed cross-bedding argue for considerable agitation of the ocean bottom.

STOP 2. Upper Fleury Member of Day Point Fm and overlying Crown Point Fm.
Upper Fleury Member of Day Point Fm and overlying Crown Point Fm. 200 yards south of the right angle bend in the road is locality R 25 (Shaw, 1968) which yielded 12 genera of trilobites, including Sphaeroxochus and Ceraurinella, from a particularly coarse pocket in the upper Fleury lime sands. Gastropods (Raphistoma) and brachiopods (Orthambonites?) are also present. This same stratigraphic level elsewhere, particularly 1 mile to the NE, displays spectacular bryozoan bioherms and the very early tabulate coral Lichenaria (Pitcher, 1964). These will be viewed on Trip F.
About 50 yards north of the road at this same stop, the silty, Maclurites-bearing limestones of the Crown Point appear. The actual contact with the Day Point is not visible but the lithologic change is evident. The Crown Point here contains several modest bioherms which have not been studied in detail. The earliest known stromatoporoids (Pitcher, 1964) are known to be important reef builders nearby in this unit and doubtless are dominant here as well (see Trip F).

STOP 3. Fisk Quarry
Middle Crown Point Formation, consisting of fine-grained, dark, silty limestone with buff-colored dolomitic partings. This is 'typical', non-reef Crown Point lithology. However, in the quarry wall and some of the cut blocks, small reeflets can be seen. These are assumed to be largely stromatoporoids and calcareous algae, although they have not been studied as intensively as the reefs at the same horizon to the east (Trip F). Evidently, these reef masses could grow at some depth in relatively silty waters. The mechanism of their establishment thus does not appear to be tectonic. Maclurites (large gastropod, rare) and a few trilobites and brachiopods may possibly be collected from the limestone, although they are not abundant.

STOP 4. Sheldon Lane
Upper Crown Point and Valcour Formations; dip north several degrees. Locality R3 of Shaw (1968) and "Road to Little Monty Bay" locality of Raymond and others.
South of the road, a very low-dipping section of Crown Point and Day Point extends for almost 2 miles across fields. The transition between the two units is similar to that on Isle La Motte. Bioherms appear not to be present in the Day Point in this area. The Crown Point, however, is only about 100-150 feet thick here, being composed largely of biohermal masses. These can be seen just south of the road. Just north of the road, in and around the abandoned quarry, are exposed bioherms usually classified as basal Valcour. They are characterized by somewhat more silt than the reefs south of the road. Similar reefs on Isle La Motte have been classed by Pitcher (1964) as having a higher percentage of bryozoan and algal components than the Crown Point reefs. Billingsaria (tabulate coral) may also be important here.
Impressive cephalopod and trilobite faunas have come from the Valcour reefs here, including Glaphurus (trilobite, Pl. 1, Fig. 4) and large asaphids, illaenids and ceraurids (trilobites). Shaw (1968) has discussed the restriction of some of these forms to the reef environment. Most of the fossils appear in fine lime mud which apparently was trapped in channels and pockets in the reef framework. Lime sands of pelmatozoan origin drape the reefs.

STOP 5. Abandoned quarry of International Lime and Stone Company
This is the uppermost part of the same section covered at stop 4 and shows well the contact of the Valcour with the overlying Black River Group (see also Fisher, 1968, Fig. 25). The upper Valcour, here, probably equals the Pamelia (lowest Black River), and is a shaly dolostone bearing Rostricellula (brachiopod, Pl. 1, Fig. 4). The contact with the overlying Lowville Limestone, a massive, gray limestone is gradational. The early horn coral Streptelasma is present in this unit, although possibly not here. The Isle La Motte appears correlative to the Chaumont west of the Adirondacks.

F. THE PALEOECOLOGY OF CHAZYAN (LOWER MIDDLE ORDOVICIAN) "REEFS" OR "MOUNDS"
Robert M. Finks
Queens College
Flushing, N. Y.
Donald F. Toomey
Pan American Petroleum Corporation
Tulsa, Oklahoma

STOP 1. Walking tour of LaBombard pasture
The walking-tour will start at the north end of the picnic ground and trailer camp on the north side of Wait Bay in southeastern Isle La Motte. It may be reached by following the main north-south road down the center of Isle La Motte to its southern end, turning left (east) to the trailer park entrance, and then turning left (north) up the hill to the picnic ground. Please note that the entire trip is on private property, and that permission must be secured from the landowners for visits.
Cross the fence and walk north to the bare exposures of the Lamottia biostrome in the Fleury Member of the Day Point Formation. CAUTION! DO NOT STEP INTO SOLUTION-ENLARGED JOINTS. SOME ARE PARTLY CONCEALED BY VEGETATION. WALK ONLY ON BARE ROCK SURFACES. THE JOINTS ARE OVER A FOOT DEEP.
The hemispherical to discoidal heads of Lamottia are closely packed in a calcarenite matrix. Joints offer an opportunity to observe their orientation in section. More than half are overturned over much of the area. Many are broken. The proportion of broken ones increases to the north and east, where the biostrome passes into calcarenite with ever fewer and smaller fragments of Lamottia. In the central area of the exposure there are belts some 10 feet wide in which fragmentation, proportion of over-turned specimens, and quantity of calcarenite matrix, are higher than elsewhere. These may represent surge channels. In the peripheral area to the northeast one may see much laminar Batostoma chazyensis surrounding the Lamottia fragments. This is the type locality for the genus Lamottia Raymond, 1924. Although Raymond's description of this bed as the "world's oldest 'coral reef" may be disputed, it still seems to be unchallenged as the world's oldest occurrence of corals of any kind.
Walk northwestward upsection, so far as fence lines, cultivated fields, and vegetation permit. DO NOT DISTURB FENCES OR LEAVE GATES OPEN! NO SMOKING WHILE WALKING THROUGH THE FIELDS; THERE IS A DANGER OF FIRE. ALSO, PLEASE KEEP OFF CULTIVATED GROUND.
At about 2000 feet N 45 W of the Lamottia outcrop, we will find small mounds of Batostoma chazyensis at the top of the Day Point Formation. They tend to show a N·S alignment, the zoaria are mostly branching rather than laminar. Possibly this is a deeper water environment than that of the Lamottia biostrome.
Continue to walk northward to a small dirt road, then walk west along it to a T-junction with a larger dirt road. Turn left and follow it southwest to a house and barn on the right. We will enter a gate into the large pasture behind the house and barn. Mr. Ira LaBombard, the present owner of the property, has kindly given us permission to enter his pasture to study the reefs in the Crown Point and lower Valcour Formations. He has requested, as a condition of permission, that NO SPECIMENS WHATEVER be collected. PLEASE RESPECT THIS ORDER. We will have an opportunity later in the day to collect from these same beds at another locality. The fossils are so beautifully displayed here that relationships may be seen without disturbing the rock. They may be photographed very advantageously on the glacially polished surfaces.
The reefs exposed here are mainly in the Crown Point formation and are the ones intensively studied by Pitcher (1964). You may examine contemporaneous reefs by walking northeastward along strike. You may examine successively younger reefs by walking northwestward upsection (slip is about 100 NW).
The reefs are exposed as mounds of light rock. The calcarenite between the reefs, and filling the channels in the reefs, is nearly black. The reefs outcropping nearest the fence were mapped by Pitcher as his Assemblage A, consisting of the stromatoporoid Cystostroma and the alga Solenopora. Those beyond to the northwest, and covering most of the pasture up to a distinct linear rise in ground, belong to Pitcher's Assemblage B. These show interesting variations from reef to reef as well as changes in faunal distribution from flanks to tops of the mounds. The fauna consists of the stromatoporoid Pseudostylodictyon eatoni, the lithistid demosponges Zittelella varians and Anthaspidella sp., the tabulate coral Billingsaria parva, the bryozoan Batostoma chazyensis, and the calcareous algae Solenopora, Sphaerocodium and Girvanella.
The fossils may be identified readily on weathered surfaces as follows:
1. Pseudostylodictyon eatoni: Large whitish masses with fine, dark laminae forming concentric patterns about centers an inch or two apart. These concentric patterns represent the mamelons and their small size is characteristic of the species.
2. Zittelella varians: Circular, dark gray bodies two to three inches in diameter, with a central circular light area representing the matrix-filled cloaca, and radial light areas, or ovoid dots, a few millimeters wide, representing the canals. In longitudinal section, the sponge is conical, and oblique sections will show the expected intermediate shapes. Some specimens have an irregular outline in cross section.
3. Anthaspidella sp.: Similar to Zittelella in color and texture, but shaped like long sinuous bodies, an inch or so thick and several inches long, when seen in cross section. A surface view of the sheet-like sponge shows a somewhat irregular mass with out a cloaca. The complete sponge has a short stalk, the whole being shaped somewhat like a distorted cake-plate. The open, "spongy" texture may help when shape fails. Needless to say, the shape and geometric arrangement of the spicules in thin section is necessary for a secure identification. Not every shapeless mass is a sponge.
4. Billingsaria parva: Small, black, oval patches, a few inches across. The dark color is very distinctive. Close inspection with a hand lens will reveal the stellate outlines of the corallites with their characteristic septal ridges.
5. Bryozoa: These weather white, either as small, branching twiglets, or as laminated sheets. Identification requires thin sections, but the outlines of the zooecia are usually visible on the weathered surface and suffice to identify it as a bryozoan.
6. Solenopora: White concentric circles, often sparry. A few inches across. This is the most common form of Solenopora seen on the reef surfaces.
7. Girvanella: Small black ovoid bodies, less than an inch in length. These are oncolites, or algal-coated shell fragments.
8. Maclurites magnus: Large coiled shells a few to several inches across. No septa. The shell substance is white in cross section.
At the rise in ground is a one-foot stromatolitic layer with many orthocone cephalopods. Pitcher called this his Assemblage C and assumed it was laid down as a blanket during a relative drop in sea level. It forms a dip slope through which appear, apparently, the tops of Assemblage B mounds, as well as small mounds of Batostoma chazyensis alone which Pitcher called Assemblage D. At the west end of this cuesta-like feature, nearest the main road, a good cross section of an Assemblage B mound is exposed (see Plate 2).
Down the dip slope, above a ten-foot interval of grey calcarenites, are mounds in the lower part of the Valcour Formation. They are composed of Batostoma campensis, together with the alga Solenopora. Some Zittelella may be found. The bryozoa are clearly dominant.
Walk northeastward along strike for about a half-mile, observing Crown Point mounds as you go. You will eventually reach the Goodsell Quarry, operated by the Vermont Marble Company. The quarry is opened in the lower beds of the Crown Point which are relatively lacking in reefs except for small stromatoporoid-algae mounds. The quarry has been intermittently active, and the stone, which makes a beautiful black marble when polished, has been widely used as an interior trim. The rock weathers light gray, and has also been used locally as a dimension stone. It was used to build the old border fort, Fort Montgomery, visible from the Rouses Point bridge.
CAREFULLY avoiding falling into the water-filled quarry, one may observe vertical sections through stromatoporoid-algal mounds and their relationships with the surrounding calcarenite (see Plate 5). By tracing laminae from the mounds into the surrounding sediment, one can see that the mounds never stood more than a foot or two above the sea floor at anyone time, though the total thickness is much greater because of the persistence of the mound population on the same spot. On the quarry benches, especially the glacially polished upper surface, one may see plan views of mounds and note their tendency to a N-S lineation. On these surfaces also, especially when wet down, one may see orthocone and other nautiloid shells, and Maclurites shells, overgrown by algal coatings.
This ends our examination of the Isle La Motte exposures. On our way back we will stop at the Sheldon Lane section, south of Chazy, where we may collect from the Crown Point and lower Valcour, in essentially the same facies.
The Sheldon Lane beds dip north. We will begin with cross-bedded upper Day Point (Fleury) calcarenite at the south end and walk through the entire Crown Point section including reef mounds with the same fauna as in LaBombard's pasture. North of the road is an old quarry in which the lower Valcour is well exposed.

STOP 2. Sheldon Lane
On our way back we will stop at the Sheldon Lane section, south of Chazy, where we may collect from the Crown Point and lower Valcour, in essentially the same facies.
The Sheldon Lane beds dip north. We will begin with cross-bedded upper Day Point (Fleury) calcarenite at the south end and walk through the entire Crown Point section including reef mounds with the same fauna as in LaBombard's pasture. North of the road is an old quarry in which the lower Valcour is well exposed.

G. SURFICIAL GEOLOGY AND GEOMORPHOLOGY OF WHITEFACE MOUNTAIN AND KEENE VALLEY
Jesse L. Craft
Carleton University
Ottawa, Ontario

STOP 1. Whiteface Mtn "Coon Pit" stop
Proceed from the bus to the chair lift and ride to the end of first lift. "Coon Pit" stop. After getting off the chair lift walk up stream to the waterfall. There is a deep glacial grove enlarging a joint. Which direction was the ice flowing to cut this grove?

STOP 2 - Top of Whiteface Mountain
After leaving the chair lift walk to the top of the mountain. Gather at the elevation marker.
From this point you can observe the only indication I have observed of continental glaciation over riding the mountain tops in the high peaks region. This is the "roches moutonnees" form of the crest on the south side of the peak.
Observe the "horn" configuration of the peak area. The "cirque form" of the valleys leading away from the peak and the very narrow "arete" ridge to the west of the peak. Could these features develop from Continental Glaciation?

STOP 3 - Atmospheric Sciences Research Centre, Whiteface Mountain Field Station
Leave the bus and walk up the jeep road to the Whitebrook valley trail (unmarked). We will be going about ~ mile up the valley. Anyone that wishes to, may stay at the centre and look around the lodge.
Whitebrook Valley Moraine. This ridge was described by Alling (1919) as a lateral moraine of a local glacier occupying this "cirque". Notice the high percentage of Potsdam sandstone pebbles lying on the surface.

STOP 4. - County Gravel Pit on 9 N
10' till, grey oxidize moderately stoney, very sandy at base, large folds of underlying sand, silt and clay carried upward into till.
50 to 100' fine sand, silt and clay upper 5' strongly contorted by load folding.

H: META-ANORTHOSITE OF THE JAY-WHITEFACE NAPPE, AUSABLE FORKS-LAKE PLACID QUADRANGLES, NORTHEASTERN ADIRONDACKS, NEW YORK
Bradford. B. VanDiver
State University of New York
Potsdam, New York

STOP 1. Locality A, Jay, Ausable Forks Quadrangle
Take woods road beginning opposite Tirolerland restaurant, 0.8 miles N. of Jay on Route 9N. Follow woods road to point where it begins to veer sharply south, 0.25 miles from Route 9N. Climb 100 yards south to exposed slabs on hilltop which has been stripped and cleared by Rock of Ages Corp. Professor Brewster Baldwin of Middlebury College prepared base map by plane-tabling on which geology and sample localities have been plotted (Fig. 2).
The exposure is representative of massive, generally porphyro-elastic, core meta-anorthosite of the "Marcy-type," but shows the considerable local compositional and textural variation encountered in this map-unit. Three local facies have been distinguished here, viz:
Facies I: A fine-to-medium grained granoblastic equigranular gabbroic meta-anorthosite, locally passing into an anorthositic metagabbro, largely confined to the northwestern portion of the outcrop. It shows many analogies with the border facies anorthosite. (Whiteface- type") and perhaps should be so mapped. Clinopyroxene (Wo40En35Fs25) takes place of hypersthene in this facies, and garnet is absent.
Facies II: This is the predominant lithic type in the exposure and consists of inequigranular meta-anorthosite with plagioclase megacrysts forming from about 25 to 70 per cent of the total rock volume, the proportion of megacrysts decreasing toward the southeast. Hypersthene is the major ferromagnesian constituent, but locally incipient rims of garnet and clinopyroxene are visible. Before concluding that the finer-grained plagioclase matrix between the megacrysts is of proto clastic origin or produced by post-crystallization deformation, examine the hypersthene grains intergrown with the matrix. Many will be seen to be optically continuous as shown by reflections from parallel cleavage surfaces and may indicate an ophitic intergrowth suggestive of a final, possibly eutectic, assemblage.
Facies III: Appearing as irregular patches up to 50 feet across in facies II meta-anorthosite is a pegmatitic phase, varying from meta-anorthosite to anorthositic metanorite. A coarse ophitic intergrowth of little-granulated plagioclase crystals and hypersthene, both attaining lengths up to one foot, is characteristic of facies. Garnet rims may be seen around some of the hypersthene.
In Table 2 are given modes measured on the outcrop (numbers painted on outcrop and located on Fig. 2) covering 6.5 feet2 apiece (619 cm2 ) with reticular spacing of one inch (2.54 cm.) Means for each of the facies and a mean for all modes, which have been apportioned among the various facies proportional to their aerial extent, have been calculated. The anorthite content of a limited number of plagioclase samples, both megacrysts and the finer grained matrix, has been determined by refractive indices. The compositional range is from calcic andesine (An44) to sodic bytownite (An72) with the average of all determinations An53. Where both matrix and megacrysts were measured in a single sample, the composition was identical in each. It is likely, however, that many of the megacrysts show chatoyant core and a non-chatoyant rim.

STOP 2. -- Omitted --

STOP 3. Roadcut South of the Flume, Route 86
In this extensive exposure (for cross-section 835 feet long prepared from a photomosaic refer to Plate 3), the relationships between three distinctive anorthositic varieties are well displayed. Coarse-grained porphyroclastic meta-anorthosite to noritic meta-anorthosite (Facies 1) with blue-black plagioclase megacrysts composing from iO- 40% of the total rock flanked by a medium-grained, generally equigranular noritic meta-anorthosite to anorthositic meta-norite gneiss (Facies II) and a medium-grained, granoblastic anorthosite with mottled pale green and pink to lavender plagioclase (Facies III). For petrographic details, see Table 3. Despite the considerable compositional and textural variation, the anorthosite content of plagioclase remains remarkably constant {ca. An55) with the principle difference being the Fe-Ti oxide inclusions of the dark plagioclase megacrysts and the absence of impurities and characteristic coloration of the (recrystallized?) plagioclase of Facies III.
Facies I meta-anorthosite closely resembles massive core meta-anorthosite of the Marcy-type although here it appears to be isolated from any extensive exposed body of such meta-anorthosite. Facies II is most closely related to border facies (Whiteface-type) meta-anorthosite and Facies III which forms most of the gorge (Flume) along the Ausable River just to the north is found interlayered with noritic meta-anorthosite at numerous localities in the Whiteface sheet to the west.
The meta-anorthosite facies are numbered in the order of their presumed relative ages as shown at this exposure. Block structure with inclusions of Facies II noritic meta-anorthosite gneiss in the much more leucocratic Facies III is especially well developed 600 feet south of the northern end of the cut. The position of Facies I meta-anorthosite in the sequence is much less certain, and it is placed first largely because of the inclusion within Facies II near the 400 feet marker. Large masses of Facies II, however, are surrounded by Facies I between the 200 and 300 feet markers. There is thus some evidence of reciprocal intrusion if geometric factors are ignored. Another example is patches of Facies III meta-anorthosite surrounded by Facies II at 400 feet. Some discussion of field criteria for age relationships will undoubtedly be warranted. In general elsewhere in the eastern Adirondacks as described in the literature, it is more common to find gabbroic meta anorthosite intruding and enveloping blocks of a more leucocratic meta-anorthosite. At the next stop we shall examine further evidence bearing upon the anorthosite sequence.
There are small inclusions of diopsidic or garnet-biotite rich fieldspathic gneisses or granofelses in Facies III meta-anorthosite at 690 feet (specimen 66-56). More extensive layers of diopsidic metasediments in Facies II gabbroic meta-anorthosite are to be found 100 yards west of the bridge over the Flume just to the north.
The outcrop shows a number of fine-grained diabase dikes from 10 inches to 6 feet thick nearly parallel to the general trend of the cut (estimated mode, samples 62-70, Table 3).
Many shear surfaces of indeterminate displacement are present, the most prominent set perhaps being about N30E, parallel to the cut face and on strike with the pronounced linear through Wilmington Notch visible to the south, a locus of probably major faulting. Augen gneiss zones in the meta-anorthosite with considerable microclinization may be seen at 100 feet and at 320 feet (estimated mode, sample 62-72, Table 3). Garnet in the meta-anorthosite appears to be localized in these gneiss zones, a phenomenon observed at many other exposures. Many secondary minerals occur along the late shear surfaces, including calcite, quartz, epidote, and chlorite. Natrolite has also been identified.

STOP 4. Stream-worn slabs under lower ski lift, elev. 1800 - 2000 feet
Between powerhouse and mid-lift station.
Drive into Whiteface Ski Center from Route 86 between Wilmington and Lake Placid. The lift will probably not be operating, so climb ski trail 600 feet vertically right (north) of stream along lift line to bare stream slabs above powerhouse.
Three distinct facies of the meta-anorthosite series are represented at this exposure, two of them related to those seen at the Flume. The earliest member of the series (Facies 1) is not, and is preserved as several rounded inclusions mostly under running water in the stream bed as it veers north of the lift line towards the upper end of the exposure. It is a fine-to-medium-grained equigranular mafic anorthositic meta-gabbro enclosed by both Facies II and Facies III rocks. For thin-section mode see specimen 65-175 in Table 5. Notable is the calcic content of the plagioclase (An70) compared to that of Facies II (An52-55)'
Facies II comprises most of the outcrop. For thin-section modes, see Table 5,: for larger-area point counts with the screen employed at Stop 1, see Table 4 -- the numbers are painted on the outcrop. The average rock is a noritic-meta-anorthosite (color index 17.85) with mean per cent plagioclase megacrysts 24.25 and plagioclase matrix 57.80. The proportion of megacrysts varies from a minimum of 7.6% to a maximum of 42%. There is also considerable textural variation with a medium-grained rock showing subtle compositional banding and a suggestion of sub-ophitic texture in the matrix the preponderant type (modes, no. 1-10). Mineralogically similar, but coarser-grained and showing better developed ophitic texture is mode no. 11, whereas modes no. 13 and 14 are somewhat more leucocratic than the average but otherwise related texturally.
Facies III is an inequigranular mediumn-to-coarse-grained leucocratic meta-anorthosite apparently cutting Facies II noritic meta-anorthosite in irregular dikes with apophyses. It is interpreted as definitely younger than Facies II, and bears out the sequence deduced at the Flume. Similar dike-like bodies of Facies III in Facies II meta-anorthosite are present in slabs along the Boreen ski trail 100 feet higher to the northwest, and may be visited if time permits.
It is worthwhile inspecting some of the coarser-grained ophitic Facies II noritic meta-anorthosites in the lower narrow portion of the stream slabs for textural evidence of protoclasis or several stages of granulation followed by crystallization. Representative of the textures seen are large, partially granulated, plagioclase megacrysts with inserted ungranulated hypersthene crystals and shattered plagioclase augen veined by noritic meta-anorthosite. Relationships may be explained by varying paths of crystallization in Di-Ab-An ternary coupled with one or more stages of cataclasis. Locally there appear to be eutectic intergrowths of plagioclase and hypersthene between plagioclase megacrysts.
Observations bearing upon the metamorphic history of the metanorthosite at this locality are the following:
1. Garnet is generally absent except along shears. At the slabs in the Boreen ski trail a little higher, leucocratic meta-anorthosite "dikes" in gabbroic meta-anorthosite have garnet and clinopyroxene + hornblende rims to hypersthene grains whereas hypersthene does not have such reaction rims in the gabbroic meta-anorthosite.
2. Hypersthene generally is rimmed by clinopyroxene or hornblende or an intergrowth of the two in the noritic meta-anorthosite under the lift. Locally, a hypersthene core is rimmed by clinopyroxene and this in turn by hornblende. It is possible that the clinopyroxene rim represents exsolution from a primary orthopyroxene or inverted pigeonite host. No exsolution lamellae have, however, yet been detected in the hypersthene. If the clinopyroxene is a result of unmixing, then the only metamorphic mineral here is hornblende.

STOP 5 (6, 7 ...) Whiteface Memorial Highway and summit
If time permits, we will ride up the Whiteface Memorial Highway, making one or more stops, and take one of the trails to the summit, preferably the northeast ridge trail from the "Wilmington turn" at the large cut below the main parking lot.
The meta-anorthosite rocks exposed in the Whiteface sheet extending from the upper slopes of Whiteface Mt. on the south to Catamount Mt. on the north and the Franklin Falls area on the west show many mineralogical, textural, and structural contrasts with the border facies of the meta-anorthosite we have thus far examined.
In general, they are much more recrystallized and relict igneous textures as observed under the ski lift at Stop 4 are rare. Foliation, and often lineation as well, is strongly developed and plagioclase megacrysts, mostly small and augen-shaped, seldom constitute more than a few per cent of the total rock. Banding is also common; and gabbroic meta-anorthosite alternates with leucocratic meta-anorthosite layers over short intervals. Garnet becomes a major phase and hypersthene a correspondingly less important constituent. There are layers of varying thickness from less than an inch to many tens of feet of mangeritic rocks, of Keene gneiss and of metasediments including coarse-grained gray quartzite and garnet-diopside granofels. Graphite is present locally near marble or calc-silicate contacts. I believe many of the physical and mineralogical characteristics of the Whiteface meta-anorthosite sheet can be explained by its tectonic position at the leading edge and base of the nappe described in the introduction to these notes.
Table 6 presents 20 modes of anorthosite rocks on Whiteface Mt. along the Memorial Highway and summit ridges in order of increasing elevation to emphasize any depth-controlled trends that may be present in the sheet. As we climb the northern slope of the Whiteface massif we are slowly passing upward through a nearly dipslope compositional layering parallel to a regional foliation.
At the Lake Placid turn (First switchback) there is a spectacular view of Lake Placid to the south. The contact between gabbroic meta-anorthosite, here somewhat more mafic than average, and mangeritic rocks is exposed just to the east of the turn. At the contact the mangerites are greenish but further away they become progressively pinker and quartz content increases. Boudins of anorthosite are enclosed in the mangerite-charnockite sequence -- is this an intrusive or tectonic relationship?
At the Wilmington turn, gabbroic meta-anorthosite structurally overlies green mangerite at the eastern end of the large cut. Meta-anorthosite blocks in the retaining wall excavated from the cut provide a good sample of the average rock in the cut. Garnet coronas are fairly common. On the upper, slightly weathered surfaces of the cut strong gently northeast-plunging lineation shown by aligned mafic minerals is shown to advantage. There are also thin quartzitic beds parallel to the foliation in the meta-anorthosite. One meta-anorthosite block not quite in place shows sharp folding of a quartzite layer.
Continuing up the trail along the northeast ridge of Whiteface Mt. to the summit, the open slabs will show the strongly gneissic, lineated, and banded character of the gabbroic meta-anorthosite. Thin plate-like quartzite layers parallel to foliation are common. From the summit, if you descend the south face 100 vertical feet you will cross the meta-anorthosite-mangerite contact once more. There is no intermediate andesine augen mesoperthite gneiss (Keene gneiss) at the boundary. Quartz content varies widely from 30-40 per cent to less than 5% in adjacent layers.
If the day is fine, it will be possible to point out regional relationships between anorthosite and related rocks in the High Peaks to the south and in the Jay-Whiteface sheet to the southeast and northwest.

J: SURFICIAL GEOLOGY OF THE INTERNATIONAL LEAD COMPANY MCINTYRE DEVELOPMENT AT TAHAWAS, N.Y.
Jesse L. Craft
Carleton University
Ottawa, Ontario

J: SURFICIAL GEOLOGY OF THE INTERNATIONAL LEAD COMPANY MCINTYRE DEVELOPMENT AT TAHAWAS, N.Y.

STOP 1. Deltaic sands, foreset beds dipping west into valley wall
Deltaic sands, forset beds dipping west into valley wall. Delta built into Glacial Lake Warrensburg (Miller 1925).
Water seems to have carried material into the Valley from the Blue Ridge moraine which lies about 3 miles due west.

STOP 2 - Blue Ridge Moraine
This is a narrow moraine complex blocking off the east west valley. Outwash from this moraine can be traced into the deltaic deposits of the last stop. The north side has been modified by water flow from the north indicating ice occupying the valley to the W of this spot with the main N-S valleys free of ice.

STOP 3 - Outwash gravel and Kame deposits
Water was flowing out of Niagara Brook along the north side of the Blue Ridge Moraine into Glacial Lake Warrensburg.

STOP 4. Striated bed rock face
Striated bed rock face on Highway 128, 2 miles west of Newcomb. Just west of BM 1595 and Lodo Pond.
Which way was the ice flowing past this point?

STOP 5 - Tahawus, McIntyre Development, International Lead Co.
Excavation of the present pit area was started in 1961. In clearing the overburden from the area formerly under Sanford Lake, a multiple till section was exposed with interglacial lake sediments between two tills. Disseminated wood fragments including material identified as Pinus strobus (David Bierhorst, Dept. of Botany, Cornell Univ.) were collected by E. Muller and the section was described (Muller 1966). The wood fragments were dated at an age greater the 40,000 years (W-1520). Muller describes two tills separated by the interglacial lake deposits.
This author observed what appeared to be a third till when visiting the pit in 1966. Detailed measurement in the pit verified the existence of three till units separated by stratified sediments.
Section at Sanford Pit (as exposed in 1966)
Top
| Feet
Coarse sand and gravel, oxidized in zones - upper part mixed with excavation fill from Tahawas village | 2 - 5
Laminated sand, silt some gravel lenses, upper parts oxidized, well developed ripple marks cut and fill structures throughout, bedding dips 8°N. | 1 - 20
Till,yellow brown oxidized moderately stoney, non-calcareous very few ore pebbles. | 1 - 25
Sandy gravel, laminated sand and silt. Numerous small folds overturned to the north. In some places this layer has been so disturbed it becomes till like in texture. | 4
Till, gray, moderately stoney, non-calcareous few Potsdam pebbles observed, no ore pebbles. Contact with overlying sediments marked by thin silt bands. | 8 - 15
Sand, yellow brown oxidized medium to coarse changes to sandy gravel a short distance to the west. | 5 - 15
Contact with underlying laminated clay not observed. |
Clay, brown with few pebbles and disseminated wood fragments including material identified as Pinus strobus (David Bierhorst, Dept of Botany, Cornell Univ.) Age greater than 40,000 years (W-1520). | 3 - 12
Gravel stratified | 1
Till yellow grey moderately stoney, noncalcareous, oxidized | 5
Till, stoney, numerous ore pebbles folded silt, sand inclusion, shear planes dipping south | 1 - 30

42nd Annual Meeting May 1, 2, 3, 1970
FIELD TRIP GUIDEBOOK
William Graham Heaslip, Editor
State University College at Cortland
Cortland, New York

A: BENTHIC COMMUNITIES OF THE GENESEE GROUP (UPPER DEVONIAN)
Jonathan W. Harrington
The University of Calgary
"The interest in a science such as geology must consist in the ability of making dead deposits represent living scenes." ---Hugh Miller
Introduction
The New York Devonian is unique in its completeness, fossil content, numerous outcrops, and relatively undisturbed nature. It is the standard reference section for North America and displays a classic example of facies transition. Stratigraphic and paleontologic investigation over the past century has resulted in a wealth of information. "Despite this, perhaps another century of rigorous study will be required before a thorough understanding of its paleontology, lithology, stratigraphy and paleoecology can be attained." (Rickard,1964).
It is doubly apropos that we examine the Genesee Group in the Cortland area. The rocks of this region and their organic remains are of considerable historical interest, having received attention since the earliest days of geological investigation in New York State. In fact, the presence of fossil shells in the Devonian rocks of New York was first noted in 1751 at a hillside outcrop in Cortland County by John Bartram, a member of Lewis Evans' Onondaga expedition (Wells, 1963).

STOP 1. Small quarry on West River Road
1. Small quarry on West River Road, just south of Bloggett Mills, Cortland Co.
This exposure in the Upper Ithaca formation (correlative with the Triphammer member in the Cayuga Lake meridian) consists of fine shales and siltstones of the Smethport depositional phase. The leptodesma biotope is represented by an abundant fauna, consisting of the spiriferid. Platyrachella,and Leptodesma, with numerous large pectinoid and mytiloid pelecypods. Most brachiopods, especially the rhynchonellids, are conspicuously absent.
2012: Guess at location.

STOP 2. Hillside quarry, 1 mile south of Cortland on Rte 90.
At this outcrop in the upper Ithaca the Big Bend phase is represented by a sequence of gray shales and siltstones. with some lenses of leached coquinite. An extremely varied benthic fauna is present. Especially abundant are Leiorhynchus mesacostale and "Pugnoides" solon.
2012: Guess at location. On topo map this route was also called 90...

STOP 3. Outcrop in Homer Gulf.
Ponticeras perlatum has been identified from exposures in Homer Gulf. This places the section in the lower portion of the Ithaca formation, probably correlative with the Renwick shale member. The lithology is extremely variable; consisting mainly of gray and reddish shales and siltstones. The fauna contains elements of both the Warrenella and Ithaca biotopes. Particularly common are: Conularia, Plumularia, Mucrospirifer, "Pugnoides", Cupularostrum eximia, Taxocrinus and linguloid brachiopods.

STOP 4. Fitzpatrick quarry ("Frozen Ocean"), north of Omro
This is the northernmost exposure of the Ithaca formation in this area. Here, a series of reddish brown and dark gray shales represents the lowermost Renwick member, and possibly part of the Cornell member of the Sherburne (Smith, 1935). The sparse fauna contains elements of the Naples and Warrenella biotopes. Especially abundant are well preserved specimens of Leiorhynchus mesacostale.

STOP 5. Fall Creek, Ithaca
This exposure, and that of adjacent gorges, constitutes the type section of the Ithaca formation. The sequence displays a complex inter-fingering of at least four of the biotopes that have been discussed.
The top of the Sherburne formation is marked by the presence of the Warrenella biotope (at the base of the falls). The commonest fossils are: Warrenella laevis, Palaeoneila filosa, Pterochaenia fragilis, Chonetes lepida, Taxocrinus ithacensis, Porcellia nias and Styliolina fissurella.
Above, in the lower vertical wall of the gorge is the Renwick member of the Ithaca, a reddish black fissile shale containing a sparse Naples fauna. Lingula complanata, Leiorhynchus mesacostale, Orbiculoidea lodensis and Styliolina fissurella are the commonest fossils.
In the upper portion of the vertical cliffs are gray shales and siltstones representing the Six Mile Creek member, containing a Tropidoleptus fauna with Platyrachella mesastrialis. Rhipidomella vanuxemi, Cyrtina hamiltonensis, Pleurotomaria capillaria and Cryptonella endora.
Above the falls the upper 300' of the Ithaca formation is represented by the Cascadilla and Triphammer members. At the base of the Cascadilla member the Ithaca biotope contains an abundant fauna, primarily of brachiopods. Especially common are: Leptostrophia, Cyrtina, Productella, Atrypa, Schizophoria, Leiorhynchus mesacostale, Cypricardella and Palaeoneilo.
The top of the Ithaca is marked by the recurrence of the Warrenella biotope, which is exposed at Forest Home, above the Cornell campus. Between these two zones are a sequence of virtually barren shales with a sparse Naples fauna, and at least one minor incursion of the Ithaca biotope.
2012: Guess at location.

STOP 6. Hubbard quarry.
This is one of the few places where the contact of the Geneseo black shale and the Sherburne formation can be seen.
The uppermost 6' of the Geneseo carry typical fossils of the Naples biotope: Barriosella spatulata, Orbiculoidea lodensis, Schizobolus truncatus, Leiorhynchus guadracostatum, Pterochaenia fragilis, Ponticeras perlatum, and fish and plant fragments .
In the lower Sherburne the following fossils occur: Chadochonus sp., Leiorhynchus guadracostatum, Loxonema noe, Palaeotrochus praecursor, Panenka sp., brevicone nautiloids and Ponticeras perlatum.
This fauna of mixed benthonic and pelagic types is similar to the "Naples fauna" of the West River shales further to the west. It seems to represent the environments of the Warrenella biotope.

STOP 7. Roadcut on Rte 13, just east of Dryden, Tompkins Co.
This exposure in the lower Triphammer member is one of the most richly fossiliferous outcrops of the Ithaca formation. It contains abundant encrusting epifauna representing the auloporid biotope, with minor incursions of the Ithaca biotope from the west and the Tropidoleptus from the east. Diversity is at a maximum, with maximum size development of Leiorhynchus mesacostale, Atrypa reticularis and Platyrachella mesastralis. Other common fossils are: "Pugnoides" solon, Porcellia nias, Mucrospirifer posterus and Cyrtina hamiltonensis.
2012: Guess at location.

B: UPPER DEVONIAN DELTAIC ENVIRONMENTS
Zeddie P. Bowen and Robert C. Sutton
University of Rochester
A. Lee McAlester and Donald C. Rhoads
Yale University
The Upper Devonian of New York is composed of a lithologically and paleontologically diverse sequence of clastics that have played an historic role in the development of geological thought. Study of these strata resulted in the classical "facies" papers by Chadwick, Caster, Cooper and others in the 1920's and 1930's. In the years since 1940, most work has been concerned with detailed geologic mapping and more precise stratigraphic correlation. These studies have been summarized on the geologic map and Devonian correlation chart of New York State (Broughton and others, 1962; Rickard, 1964).
In New York State, the Upper Devonian marine strata crop out in a generally east-west belt over 200 miles long and extend from Lake Erie on the west to the Catskill Mountains in the east. These strata have been subdivided into seven groups, some of which are marked by thin, persistent black shales that enclose eastward-thickening rock wedges. Within each wedge diverse lithologies and faunas can be recognized and delineated. Moreover, similar lithologic and faunal associations can be recognized in each wedge forming the basis for the facies concept mentioned above. That portion of Rickard's Devonian Correlation Chart (formational and members names omitted) with which this field trip is concerned is shown in figure 1.
In 1965, the writers began an analysis of the Smethport or Chemung facies using both paleontological and sedimentological evidence to reconstruct its paleo-environments. The initial studies were confined to the Sonyea Croup in order to define a set of essentially contemporaneous environments that could be compared with those in modern deltas (Sutton, Bowen, and McAlester, in production). The second or current phase of research has dealt with the post-Sonyea Chemung facies in central and western New York.

B: UPPER DEVONIAN DELTAIC ENVIRONMENTS

STOP 1. Open Shelf (Harford Mills)
Lithology and Structures:
Interbedded gray and dark gray shales, siltstones and mudstones. Small flute casts, groove casts, cross- laminae concretions, tracks and trails
Paleontology (only abundant forms listed)
Shelly fossils relatively rare. Tracks, trails, burrows (7 taxa found, all rare)

STOP 2. Prodelta (Berkshire)
Lithology and Structures:
Mudstone interbedded with siltstone and minor amounts of shale and sandstone. Groove casts, cross- laminations and cuspate ripples.
Paleontology (only abundant forms listed)
Leiorhynchus, Chonetes, Productella, Leptodesma, Ambocoelia Tracks, trails and burrows plus 9 other less common taxa

STOP 3. Platform (Smithboro)
Lithology and Structures:
Mudstone interbedded with sandstone, shale, siltstone, and coquinite. Cross-bedding, laminations, ball and pillow, cuspate ripples, load casts
Paleontology (only abundant forms listed):
Shelly fossil abundant. Atrypa, Cyrtospirifer, Productella, Crinoids, Douvillina, Auloporid corals, Ambocoelia, Cornellites, Schuchertella, Rugose corals, Tylothyris, Plant fragments plus 13 other less common taxa

STOP 4. Delta Front Sands (Glory Hill)
Mostly sandstone with small amounts of shale, mudstone, and coquinite. Cross-bedding, cross-laminations, current ripples, parting lineation, mud chips
Paleontology (only abundant forms listed)
Large shelly fossils abundant. Tracks, trails, and burrows. Productella, Thiemella, Atrypa Nervostroehia(?) Cyrtosperifer, Chonetes, Tylothyris, Crinoids, Douvillina, Auloporid corals, Ambocoelia, Plant fragments, Rhynchonellids, Cornellites plus 8 other less common taxa

STOP 5. Near Shore Facies: Channels, Lagoons, and Levees (Ingraham Hill Quarry)
Sandstone and shales with small amounts of shale-pebble conglomerate. Cross-bedding, linguoid ripples, groove casts
Shelly fossils uncommon. Plant fragments and tracks, trails and burrows abundant, plus 18 other less common taxa.

C: TRANSITIONAL SEDIMENTARY FACIES OF THE CATSKILL DELTAIC SYSTEM IN EASTERN NEW YORK STATE
Kenneth G. Johnson
Skidmore College
One of the greatest thicknesses of Devonian rocks on the North American continent is at the northeastern end of the Allegheny Synclinorium in east-central Pennsylvania and southeastern New York. The sequence crops out along a north-facing escarpment extending from Lake Erie to the Catskill Mountains, a distance of some 300 miles. The escarpment continues south along the west side of the Hudson Valley into the Valley and Ridge physiographic province of the Appalachian highlands. The New York sequence is accepted as the standard for the Devonian System of North America. In the Catskills, although the top has been eroded, the Devonian is some 10,000 feet thick. It thins to about 2500 feet at the western edge of New York State and also thins toward the southwest. In northeastern New York Devonian rocks have been removed by erosion. In New York State the Devonian sequence was only slightly affected by the Appalachian Revolution; it was deformed into gently undulant folds. More intense tectonic forces to the southwest in Pennsylvania folded the same strata into elongate, plunging anticlines and synclines.
The upper Middle Devonian and Upper Devonian of eastern New York and Pennsylvania consist of a thick wedge of continental rocks that have a progradational relationship to marine formations farther west. These rocks have a deltaic character.
The deltaic wedge is composed of detritus derived from a source area east of the present-day Catskill Mountains which was being elevated by the first pulses of the Acadian Orogeny. At the base of the clastics is an interval of some 2500 feet of fossiliferous sandstones and shales (Hamilton Group) which thins toward the west and southwest. Penetrating eastward from the marine basin into the upper Hamilton clastics are two thin fossiliferous limestone beds (Centerfield and Portland Point) which were deposited during the time that the source terrain was in the beginning stages of uplift. The Tully Limestone, a transgressive carbonate tongue at the base of the Upper Devonian, represents the last significant limestone deposition in the New York Devonian prior to the overwhelming of the marine basin by clastic influx.
After deposition of the Tully, uplift apparently accelerated and continued on a large scale into the Mississippian. A thick wedge of clastic continental sediment (Catskill lithofacies) was deposited at the margin of the basin. The red and green-gray sandstones, shales, and conglomerates of this wedge inter-finger westward with littoral and shallow marine (Chemung lithofacies) sandstones and shales. These grade into dark-colored shales and siltstones (Portage lithofacies) farther west that are of deeper marine origin. The irregular, interfingering contact between the continental beds and the marine formations rises stratigraphically towards the west and the continental beds consequently have the appearance of over-riding the marine strata. This prograding relationship, the result of displacement of the late Devonian sea by the expanding clastic wedge, is shown in the cross-section along the N.Y. - Pa. border (Fig. C-l). Dunbar and Rodgers (1957, p. 137-140) give a concise description of the New York Middle and Upper Devonian from the paint of view of the facies concept. A correlation chart by Rickard (1964) shows the relationship of the depositional phases of the Devonian rocks in New York State.
Within the Tully Limestone and its eastern clastic correlatives are rocks that are representative of the spectrum of sedimentary environments that comprised the Catskill deltaic system during early Late Devonian Time. These were studied (Fig. C-2) in order to develop associations of criteria that will permit recognition of sedimentary environment elsewhere in the Catskill complex.

C: TRANSITIONAL SEDIMENTARY FACIES
OF THE
CATSKILL DELTAIC SYSTEM IN EASTERN NEW YORK STATE

Headwaters of Genegantslet Creek.
On right (S) swamp which forms headwaters of south flowing Genegantslet Creek.

On left (N) large outcrop of Chemung Lithofacies.

Cross Canasawacta Creek in South Plymouth

On right (S) large gravel pit in glacio-fluvial sedimentary deposit.

Cross Chenango River

Road cut in Catskill Lithofacies.
On left (N) excellent example of alluvial channel facies (cross-bedded, gray, graywacke) resting on over-bank facies (red shale),

Cross Unadilla River

Descend river terraces.

Center of Morris.
Note stone buildings constructed of Chemung lithofacies flagstone.

On left large gravel pit in glacio-fluvial deposit.

Ahead on left large gravel pit in Kame deposit.

Horizontal Chemung lithofacies
On left in used car lot adjacent to Nick's Diner horizontal, very thin bedded Chemung lithofacies containing abundant spiriferid brachiopods.

On right view of glacial deposits in mouth of Charlotte Valley.

On right across valley very large gravel pit in Kame terrace.

STOP 1. Flow rolls in Lithosome C.
This outcrop contains an example of the flow-rolls which are locally common in Lithosome C. The flow-rolls occur as beds of internally disturbed structure underlain and overlain by horizontal, well-bedded strata. Within the flow-roll beds are nodule-shaped, concentrically laminated masses of medium gray, very fine-grained sandstone enclosed in slightly darker colored siltstone. The laminar structure is due to concentric, extremely thin, dark laminae composed largely of very fine plant fragments. The enclosing siltstone commonly has a diapiric relationship to adjacent pillows. This outcrop is at the distal edge of the nearshore (bar and lagoon) facies.

Kame and Kettle topography.

Passing through Kame and Kettle topography.

On left well defined river terrace.

On right outcrop of dark Gilboa Formation shale.

Grand Gorge

STOP 2. Hardenburgh Falls
On right power sub-station. Park and walk down unsurfaced road across from power station.
The beds here are medium gray and olive gray, trough cross-bedded, fine to medium-grained, graywacke and medium gray, shaly siltstone of Lithosome C. Pebble and coquinoid conglomerate lenses, rich in plant fragments, are common. The strata are interpreted as being of tidal channel and tidal flat origin.

Kame (?) topography.

Cross Schoharie Creek.

On right sandstone ledges of Catskill lithofacies (Lithosome D).

On right more sandstone ledges of Catskill lithofacies.

STOP 3. Manor Kill Gorge
The beds exposed in the Manor Kill Gorge are within the upper part of the Hamilton Group. Those in the lower part of the section, adjacent to the Schoharie Reservoir, are trough cross-bedded, burrowed, medium-grained sandstone of Lithosome C assigned to the tidal channel facies. Some of these sandstones are rich in plant material and in a few places during low water stages of the reservoir fossil seed-fern stumps may be seen. The remainder of the section upstream consists of interbedded red and green shales, dark gray shales and medium gray, shallowly cross-bedded, fine-grained sandstone; interpreted, respectively, as distal alluvial plain, tidal flat and tidal channel facies. Walk down path on left (W) side of road to east bank of reservoir at mouth of Manor Kill to observe cross-bedded, burrowed sandstone.

On left Gilboa Dam constructed mainly of tidal channel (and bar?) sandstone of Lithosome C.

STOP 4 Display of Gilboa seed-ferns
Display of Gilboa seed-ferns taken from quarry (abandoned) a short distance back in woods. Over 200 such seed-fern stumps were taken from this quarry. They apparently represent a distal alluvial plain or tidal swamp which was buried by shifting tidal channel sands.

STOP 5. Graywacke
Park on right side of road opposite outcrops near base of steep hill. Outcrop consists of medium gray and olive gray, tabular and trough cross-bedded, fine to medium-grained, immature graywacke. The sandstone contains well-developed lag accumulations of large spiriferid brachiopods and a few large burrow structures. The sandstone is interpreted to represent a tidal channel deposit.

STOP 6. Lithosome D
Park on right opposite red beds.
Outcrop consists of grayish red, highly micaceous siltstone and silty, very fine-grained sandstone of the overbank alluvial facies (Lithosome D). Dark greenish gray mottles are common in these beds.
Resting in channel contact on the red beds is well cross-bedded, apparently unfossiliferous, medium gray, very fine-grained sandstone and olive-gray, fine-grained sandstone. Within this 30 foot sandstone interval is a well-developed compound channel that migrates to the right (SW) upward in the section.

D: PALEONTOLOGY, STRATIGRAPHY, AND PALEOECOLOGY OF THE LUDLOWVILLE AND MOSCOW FORMATIONS (UPPER HAMILTON GROUP), IN CENTRAL NEW YORK
Thomas X. Grasso
Monroe Community College
Rochester, New York
Introduction
The Middle Devonian Hamilton Group of New York State is structurally simple and highly fossiliferous, thereby lending itself to detailed stratigraphic and paleontologic studies.
The writer (1966) examined the Hamilton sequence in the Tully Valley to determine the sequence of lithologies and faunas. The zones thus determined were compared with those defined by Cleland (1903), who made a similar study of the Hamilton Group along the Cayuga Lake meridian, 30 miles west of the Tully Valley (Fig. D-1). A paleoecological interpretation of the Hamilton rocks of the Cayuga Lake region was made by Fernow (1961).
This trip was repeated as trip H.

D: Ludlowville and Moscow Formations

Roadcut on east side of 1-81 is in the Upper Dev Ithaca Fm.

STOP 1. Roadcut on east side of U.S. Rt.11
Elevation 1280': .3 miles north of the junction of N.Y. Rts. 80 and 11 (Tully Quad.).
Exposed thickness: Windom Member 35'
The top of this exposure is stratigraphically below the Windom outcrop on Kingsley Road (STOP 5). The Windom at this locality (STOP 1) is approximately 100 feet below the base of the Tully Ls and is fossiliferous.

STOP 2. Roadcut, on west side of LaFayette Rd
Elevation 1330': Roadcut, on west side of LaFayette Rd. just before the bend in this road, about .4 miles northwest of LaFayette (Jamesville Quad.).
Exposed thickness: Otisco Member 30'
This exposure of the Otisco is stratigraphically above the Joshua Submember and below the Ivy Point. It is extremely fossiliferous. Mucrospirifer mucronatus, Spinocyrtic granulosa, Athyris spiriferodes, Megastrophia cava are some of the brachiopods, Cornellites flabella, Modiomorpha mytiloides, Pseudaviculopecten princeps, Paleoneilo constricta, Cypricardella bellistriata are some of the pelecypods found here.

STOP 3. Base of WSYR TV Tower on Miller Hill
Elevation 1400'; Base of WSYR TV Tower on Miller Hill, .3 miles southwest of the intersection of Sentinel Heights Road and Bull Hill Roads (Jamesville Quad.).
Exposed thickness: Joshua Submember 15.5'
Numerous solitary rugose corals occur here such as Cystiphylloides, Siphonophrentis, and Heterophrentis. The colonial rugose coral Eridophyllum sabcaespitosum is also abundant.

STOP 4. Lords Hill, on N.Y.80
Elevation 1380': Lords Hill, on N.Y.80, south of the junction with U.S.20 (South Onondaga Quad.).
Name | Exposed Thickness | Elevation | Notes
Portland Point Member | 10' | |
Owasco Member | 2' | Elev. 1380' |
Spafford Member | 2' | |
Ivy Point Member | -not measured | | -small exposures on both sides of road
Joshua Submember | -70' (projected) | Elev. of top 1280' | (Oliver, 1951)
Joshua corals are found in the regolith on both sides of the road. The Owasco contains an abundance of Allanella tullius and Mucrospirifer mucronatus. The basal crinoidal layer of the Portland Point nests directly on top of the Owasco Member. This is succeeded by 9 feet of interbedded shales and thin limestones.

STOP 5. Roadcut. on both sides of Kingsley Road
Elevation 1500': Roadcut. on both sides of Kingsley Road just west of the intersection of Hitchings Rd. (South Onondaga Quad.)
Exposed thickness: Windom Member 28'
The top of this exposure is about 20 feet below the base of the Tully Limestone. The Windom here is unfossiliferous.

STOP 6. Peppermill Gulf
Elevation 1050': Peppermill Gulf, parallel to and just east of Hogsback Rd., 1.3 miles west of the junction of U.S.20 and N.Y. 8O (South Onondaga Quad.).
Exposed Thickness: Centerfield Member 30'
Butternut Member --
A waterfall just north of U.S.20 exposes approximately 30 feet of Centerfield. The Butternut - Centerfield contact is gradational - is therefore difficult to establish. The Centerfield is a coarse siltstone at this locality. Fossils are difficult to extract because of the lack of good bedding plane exposures.

STOP 7. Moonshine Falls on Paines Creek
Elevation 475' : Moonshine Falls on Paines Creek, 1 mile south of Aurora (Sheldrake Quad.). Unnamed gravel road on right leading downhill to a bridge over Paines Creek -Walk down road to Paines Creek and then downstream
Exposed thickness: Ledyard Member --
Centerfield Member 25'
Centerfield at this locality is abundantly fossiliferous with numerous species of brachiopods, pelecypods, corals, and bryozoans. The Ledyard Member sharply overlies the Centerfield and carries a fauna of small, thin shelled pelecypods and brachiopods. The contact between these 2 units occurs just upstream from the waterfall.
2012: Bridge was visible in 1995 image.

STOP 8. Black Rock on Paines Creek
Elevation 720': (Sheldrake Quad.).
| | Exposed thickness:
| Dense fossiliferous shale | 28"
Portland Point Member | Blue-gray fossiliferous shale | 8"
| Basal crinoidal layer | 16 -20"
King Ferry Member | | 8'
The lip of the falls is 8 feet lower than the base of the crinoidal limestone, therefore the uppermost King Ferry is accessible here. The Portland Point is very fossiliferous containing numerous brachiopods, pelecypods, ostracodes, crinoids and trilobites.

STOP 9.Portland Point Quarry on east lip of Cayuga Trough
Elevation 620': (Ludlowyille Quad.).
Exposed thickness: |
Geneseo Black Shale | 15'
Tully Limestone | 16'
Windom Member | 5'
This locality is one of the most fossiliferous exposures along the Cayuga Lake meridian. Numerous corals, bryozoa, crinoids, brachiopods, pelecypods, trilobites, and gastropods are found in the upper 5 feet of the Windom. (see Guidebook -31st Annual Meeting N.Y.S.G.A. 1959 Ithaca, N.Y.)
At the south end of the quarry a thrust fault overthrust to the northwest occurs in the Tully Limestone and has drag folded the upper Windom at this locality.
On the east side of the quarry an alnoite dike about 1 foot thick occurs in one of the N-S joints.

STOP 10. Roadside quarry on Portland Point Road
Elevation 460': (Ludlowville Quad.),
Exposed thickness:
King Ferry Member --
The King Ferry Member exposed here is about 20 feet below the Portland Point Member.

E: MINERAL INDUSTRIES IN PARTS OF ONONDAGA, CORTLAND AND TOMPKINS COUNTIES
Newton E. Chute
Syracuse University
Central New York has had important production of industrial minerals and rocks for many years. In 1967 (Minerals Yearbook) the order of value of these products in Onondaga County was as follows:
1st Salt
2nd Lime
3rd Stone (also 3rd county in state)
4th Cement
5th Sand and gravel
6th Clays
Industrial minerals and rocks now being produced in the field trip area are described briefly. Those formerly produced are discussed in the following section.
Repeated as Trip I

STOP 1. Finger Lakes Stone Company's sandstone quarry
The quarry is in the upper part of the Enfield Formation which is about 650 feet thick in the Ithaca area. Layers of sandstone alternate with layers of shale in the quarry. Slabs of sandstone are obtained without blasting by drilling holes on seams and separating them with wedges. The slabs are cut to the required sizes in the mill by diamond and wire saws. Pieces with good joint surfaces are used for seam face stone. Those with sole markings on bedding surfaces are used for special surface effects. The stone is laid in various patterns with different finishes, as illustrated by the exterior of the company's office at the quarry.

STOP 2. Quarry of the Cayuga Crushed Stone Company
This is the old quarry in the Tully Limestone and the Geneseo Shale that was worked by the Penn.-Dixie Cement Company until 1948. The quarry is on the crest of the Portland Point anticline above the Cayuga Rock Salt Company's mine. The Cayuga Crushed Stone Company reopened the quarry and has worked it for a number of years.
The Tully Limestone, which is 16 to 18 feet thick at the quarry, is underlain by fossiliferous Moscow Shale of Middle Devonian age and is overlain by unfossiliferous Geneseo Shale of Upper Devonian age.
Two peridotite dikes have been known in this quarry for many years. They are marked on a map in the guidebook for the 31st annual meeting of the N.Y.S.G.A. sponsored by Cornell University in 1959. One is shown to extend for about 1700 feet across the southeastern part of the quarry.
A dike, 1'5" thick, is presently exposed in the southern part of the quarry face and for about 100 feet on the quarry floor. It diminishes in thickness to about 6 inches near the south end of the exposure. The dike is vertical and strikes N 5 to 10 degrees W parallel to a prominent set of joints about at right angles to the axis of the Portland Point anticline .
The first description of a peridotite dike in this quarry was by Sheldon in 1921. Other descriptions are by Martens (1924) and Broughton (1950).
A cluster of six or seven dikes each 6" to 8" thick was observed recently in the middle part of the quarry face by J.J.Prucha. He also knows of at least eight peridotite dikes in the salt mine below the quarry (personal communication, April 1970). Martens (1924) described this dike rock as kimberlite or alnoite depending upon the presence of melilite, an essential constituent of alnoite. Broughton (1950) did not observe any melilite in the thin sections he examined and called the rock kimberlite .
Of particular interest at this quarry is the unusual thickness of glacial overburden and shale that it is economical to strip to quarry the limestone. At the south end of the quarry in particular, the depth of the stripping is several times greater than the thickness of the limestone quarried. The favorable location of the quarry for marketing stone in the southern part of the state is an important factor in making the unusual depth of stripping possible. Small quarries have been worked in the Tully Limestone in various places in central New York in the past, but this is the only one worked in recent years.

STOP 3. Salt mine shaft and Cement Plant
The Cayuga Rock Salt Company's mine shaft and the former plant of the Penn.-Dixie Portland Cement Company.
A brief stop will be made to observe the headframe of the Cayuga Rock Salt Company's mine and the remains of the old cement plant on the lake shore.

STOP 4. Brine well field
Brine well field of the Solvay Process Division of the Allied Chemical Corporation.
Brine is obtained from wells about 1100 to 1200 feet deep that penetrate salt beds in the Syracuse Formation of the Salina Group. The brine is piped to the company's plant at Solvay for the manufacture of soda ash and chemicals.
A tour of the brine field will be conducted by Mr. Michael Slexak who is a geological engineer with the Solvay Process Division.
2012: Location is uncertain.

STOP 5. Lunch stop at Clark Reservation State Park south of Syracuse.
The remarkable abandoned waterfall and plunge basin in this park were formed by a temporary river that drained a glacial lake in Onondaga Creek Valley when glacial ice blocked the drainage to the north.
The lip of the falls is on the Edgecliff Member of the Onondaga Limestone. The Nedrow and Moorehouse Members are exposed nearby at higher elevations on the north and south sides of the plunge basin.
This is the type locality for the Clark Reservation and Jamesville Members of the Manlius Formation. These and other members of the Manlius, except the Thacher which is covered, are exposed along the stairway on the south side of the plunge basin. The section here is as follows:
Onondaga limestone Clark Reservation and Jamesville
17 to 18' | Edgecliff member, 2' of sandy limestone and calcareous sandstone at base.
5'9" | Pools Brook member, dolomitic limestone
19' | Jamesville limestone, numerous stromotoporoids in upper 8 feet.
3'13" | Clark Reservation oolitic limestone
9'10" | Elmwood dolomite and dolomitic limestone member
| 2'7" | Elmwood C argillaceous dolomite submember
| 2'9" | Elmwood B dolomitic limestone submember
| 4'6" | Elmwood A argillaceous dolomite submember
22' | Olney limestone to bottom of exposure

STOP 6. Limestone quarry
Limestone quarry of the Solvay Process Division of the Allied Chemical Corporation, located on the north side of the Seneca Turnpike just east of Jamesville.
This is one of the largest limestone quarries in the state and provides a good illustration of selective quarrying. The rock units quarried are as follows:
Onondaga Limestone Formation
Moorehouse Member
Nedrow Member
Edgecliff Member with several feet of sandstone at the bottom
Manlius Limestone Formation
Pools Brook Member
Jamesville Member
Clark Reservation Member
the quarry floor is at the top of the Elmwood Member below the Clark Reservation Member
The Clark Reservation, Jamesville, Pools Brook, and the noncherty part of the Edgecliff member have the highest purity, and they are quarried for use by the Solvay Process Division for kiln stone and for cement manufacture by the Alpha Portland Cement Co. The Onondaga Limestone above the Edgecliff Member is quarried for crushed stone. The sandstone at the base of the Edgecliff Member and the cherty part of the Edgecliff are stripped separately and wasted.
The Tioga Metabentonite, which is about 8" thick, overlies the Moorehouse Member and separates it from the Seneca Member above. The metabentonite is unsatisfactory in crushed stone and is stripped along with some of the Seneca Member where they occur at the south edge of the quarry.
Two reverse faults that strike about N 70 degrees W and dip southward offset the beds in the quarry a few tens of feet. Fluorite and calcite crystals have been found in fractures along the fault zones.
Additional points of interest to be seen on this quarry property are an old lime kiln, an old quarry worked for Elmwood argillaceous dolomite used for natural cement manufacture, and part of an old gypsum quarry in the Forge Hollow Formation of the Bertie Group.

STOP 7. Split Rock quarry
STOP 7. Split Rock quarry located at the west end of Split Rock Gulf Road about 0.7 mile southwest of the junction of Route 173 and Onondaga Blvd.
This quarry illustrates the influence of the unconformity at the base of the Onondaga Limestone on the amount of limestone available for quarrying. Here the Edgecliff Member of the Onondaga overlies Elmwood A unit of the Elmwood Member. The Clark Reservation, Jamesville and Pools Brook limestones, seen at the Solvay Process Division's quarry, were eroded prior to the deposition of the Onondaga Limestone.
Most of the floor of the bottom part of the quarry is on the top of the Rondout dolomite, about 33 feet of Olney and Thacher Limestone overlie the Rondout. Two or three stromatolite zones and a dolomite bed are present in the lower part of the Thacher. The upper part of the Thacher and the Olney are mainly the "drab and blue" type of alternating thin beds of dolomitic brownish weathering and purer gray weathering limestone. The Edgecliff Limestone at the top of the south side of the quarry contains some small coral reefs a few feet to a few tens of feet in diameter.

STOP 8. Syracuse Pottery Company plant and clay pit.
The plant is on the west side of Pottery Road about 0.9 mile north of its junction with Route 173 and 2.2 miles east of Warners.
This company, which manufactures mainly flower pots and urns from glacial clay dug a short distance west of the plant, has been operating nearly continuously since about 1875. The clay is dug to a depth of 8 feet after stripping 6 to 10 inches of topsoil. The part of the clay bed under a swamp has different firing characteristics from the part on higher ground. The part under the higher ground has been partly leached of calcium carbonate and this apparently causes the clay to burn redder and to shrink more than the clay from below the swampy area. These two types of clay are blended to obtain the desired firing characteristics.
After the flower pots are molded by presses, they are fired in a tunnel kiln at a temperature of 1800 degrees F. Some of the pots are glazed and some are coated with colored enamel.

STOP 9. Old portland cement plant and marl pits
The old portland cement plant of the Empire Cement Company and the marl pits. Ruins of the old cement plant can be seen on the north side of the old Erie canal a few hundred feet west of Newport Road at Warners. The water-filled marl pits are west of the plant between the canal and Canal Road.
This cement plant is historically significant, because it was one of the early portland cement plants and because marl was used as a source of calcium carbonate. The plant was first built in 1886, and operated until about 1908. Depletion of the supply of marl suitable for cement manufacture may have been a factor in the plant closing. Two other cement plants that used marl were operated for a short time in this region. One was the American Cement Company's plant about 5 and 1/2 miles west of Warners and the other was at Montezuma north of Cayuga Lake.

STOP 10. Plant of the Onondaga Lightweight Aggregate Corporation
Plant of the Onondaga Lightweight Aggregate Corporation located about 0.6 mile east of Warners on the north side of the railroad.
Lightweight aggregate has been produced here since 1954. Some years previously the plant was used by the Onondaga Brick Corporation for the manufacture of building brick. The raw material is Vernon Shale obtained from an old quarry about half 8 mile north of the plant (Stop 11). After crushing the shale is sized, mixed with coal, and sintered on a sintering machine at 2400 degrees F. The sintered chunks are crushed and screened to four sizes for marketing. This plant is said to be one of the first lightweight aggregate plants in New York State. The product is marketed widely, especially in the central part of the state.

STOP 11. Vernon Shale quarry
Vernon Shale quarry of the Onondaga Lightweight Aggregate Corporation located in the hillside on the north side of Brickyard Road about half a mile northeast of Canton Street in Warners.
The quarry, which probably is in the upper part of the Vernon, exposes 25 to 30 feet of red and greenish gray shale. Gypsum nodules are present in the shale in places and also some small shiny black crystals of specular hematite. Usually the hematite crystals are associated with cavities that probably contained gypsum or salt. Some of the cavities are molds of salt hopper crystals. In places the red shale contains very irregular patches of the green shale suggesting partial decolorization of the red shale.
This quarry is one of the few places in central New York where more than a few feet of the Vernon are well exposed for examination.

STOP 12 . Gravel pit
Gravel pit on the south side of Lake Road, opposite the south end of Green Lake, about a mile west of Tully.
The pit is close to the Valley Heads moraine near Tully and has some interesting features. The gravel in the pit appears to have come from two different sources. probably because of diversion around the ice block that stood in the position of Green Lake. The gravel in the western half of the pit came from the northwest and is much lower in shale than the gravel in the eastern half which cross bedding and imbricate structure show came from the northeast. Shale is abundant in a layer 2 to 4 feet thick near the middle of the face on the east side.

STOP 13. Alluvial Fan at Preble
Stop on Route 281 at Preble to view the alluvial fan built in the main valley at the mouth of Otisco Valley.

STOP 14. Gravel pit operated by the Cortland Ready Mix Company.
This pit is on the west side of Route 11 about a mile north of the Homer city line. Entrance to the pit is opposite the end of Health Camp Road.
This pit, and the pit of the Concrete Materials Corporation nearby on the east side of Route 11, illustrate the kind of gravel available in this part of the valley of the West Branch of the Tioughnioga River. Gravel and sand are dug to a depth of about 40 feet below which is a thick deposit of silt and clay. Most of the gravel is dug from below water and is not weathered.

STOP 15. Gravel pit in a kame
Gravel pit in a kame on the northwest side of the valley of the east branch of the Tioughnioga River, about a mile northeast of Route 81. This pit provides a good illustration of the Olean type of gravel which is characterized by much local shale and siltstone. This type of gravel is of very poor quality and is usable mainly for fill. Varved clay exposed on the side of the kame may indicate the presence of a lake in the valley after the kames formed.

F: DEGLACIATION OF THE EASTERN FINGER LAKES REGION
James Kirkland
State University of New York at Binghamton
Acknowledgments
The writer is indebted to Dr. James Bugh at the State University of New York College at Cortland and Or. Donald Coates at the State University of New York at Binghamton for their encouragement and criticism.
Regional Setting
The field trip area is located in central New York State and comprises parts of the Tully, Otisco Valley, Truxton, Homer, Sempronius, and Cortland 7.5 minute U.S.G.S. topographic quadrangles. This region consists predominately of gently southward dipping Devonian shales with an east-west system of broad anticlines and synclines (Tarr, 1909).
There is wide disagreement in the literature concerning residuals from preglacial erosion.
Durham (1954) described three erosion surfaces in the surrounding region, the highest or Schooley Peneplain at 1600 to 1999 feet, the next between 1500 and 1700 feet, and the lowest between 1100 and 1300 feet. He further considers only the Schooley Peneplain to be a true peneplain and the others to be the result of structural control by resistant strata.
Denny (1956) concluded that remnants of former peneplanation have been reduced.
Muller (1965) stated that summit accordance is valid only if summit reduction by glaciation is light and that " ... summit contours generalized to a six mile grid give an impression of imperfect summit accordance." (1966)
Clayton (1965) stated: "... the whole of the relief near the Finger Lakes is the work of ice, and is quite independent of the form of the preglacial landscape. The destruction of that earlier landscape is almost complete, ... "
The present form of the topography is probably the result of multiple cycles of glaciations and interglacials (Coates, 1966) with erosion by late Wisconsinan glaciation contributing little to the present bedrock form of the topography.

TRIP F: DEGLACIATION OF THE EASTERN FINGER LAKES REGION

State University College at Cortland
The campus of the State University College at Cortland is situated on a bedrock hill or umlaufberg which rises 110 feet above the surrounding outwash plain. The knob represents an extension of the ridge extending northeast from Cortland. Muller (1966) attributes the formation of the knob to ... "Concentrated glacial scour at the south end of the Tully-Cortland trough effected the reducing and isolating of the knob. Aggrading valley fill completed separation of knob from upland."
Query: How many cycles does the formation of the knob represent and what effect have fluvial processes had in its formation?
The valley fill underlying Route 13 is composed of two gravel units, each approximately 50 feet thick, separated by 100 feet of sand and silt. The intermediate unit presumably represents conditions of low gradient and restricted drainage south across the Tioughnioga col. The upper gravel relates to deposition of coarse outwash aggrading east-north eastward from the Valley Heads moraine just west of South Cortland.

Crossing South Cortland outwash plain
Proceed past Munsons Corners crossing South Cortland outwash plain, rising southwest at about 20 feet/mile. Several streamlets from the till slope to south disappear into this permeable coarse gravel plain.

STOP 1. South Cortland Kames
Active borrow pits in kame complex on south flank of valley expose structure of ice disintegration deposits comprising a linear ridge which is relatively smooth on the distal slope but with massive kame-like aspect to the northwest. Lateral variability of sorting and coarseness is characteristic. The gravels are characterized by crystalline-carbonate-clastic relationship of about 5:15:80 which is representative of through valley drift in this area. The kame complex contains sections of highly cemented gravels. What does this indicate about carbonate leaching and ground water conditions?

Ice contact face of kame terrace
Descend sharply on ice contact face of kame terrace, into complex of ice disintegration deposits marking stagnant toe of north-eastward trending Valley Heads ice tongue.

Continue north through Gracie across ice disintegration complex.

Cross abandoned meltwater channel
Cross abandoned meltwater channel cut by stream flowing from melting ice blocks responsible for the Fish Hatchery kettles.

Post glacial lake
Cross Otter Creek. Note lake of post glacial modification of outwash plain.

Alluvial fan of Dry Creek.
Turn left (W) onto Kinney Gulf Road built largely across alluvial fan of Dry Creek.

Start of Kinney Gulf
Dry Creek and road pass through narrow rock-walled gorge which shortly opens out to form Kinney Gulf.

Valley Heads moraine
Rise across outwash to well-defined Valley Heads valley-stopper moraine which forms divide between Dry Creek (Susquehanna drainage) and headwaters of Fall Creek (St. Lawrence drainage).

Glacial striae oriented S45W
Carney (1909) reported glacial striae to be oriented S45W on summit of west Hill to north of intersection.

Glacial striae oriented S71E
On summit of southeast end of Summer Hill west of route, Carney (1909) reported glacial striae to be oriented S71E, indicating opposing directions of ice flow during late Wisconsin Stage.

Cross small tributary of Fall Creek which drains Lake Como.

Intermorainal Basin
To northwest (left ahead) the valley floor opens out as an inter-morainal basin, part of which is occupied by Lake Como. Lower slopes enclosing the basin on north and east are marked by strong kame and kettle development.

Start of Homer Gulf
Proceed across nose of stagnant ice deposits at drainage divide, before entering Homer Gulf, a canyon incised 300 to 500 feet deep.

STOP 2. Homer Gulf
Post-glacial modification of the upper part of the Gulf is minor, and latest gorge-cutting relates to Valley Heads glaciation.
Note the fan deposited by water from Homer Gulf in the Skaneateles trough.
Query: Is this gulf a product of a single episode of gorge-cutting? Is the moraine position on the divide co-incidental?

Skaneateles trough
Proceed north over outwash and postglacial alluvial fan deposits of Skaneateles trough.

Cross Valley Heads terminal moraine.
Road follows an open, irregular channel cut by meltwater during wasting of stagnant toe of the Skaneateles ice tongue.

STOP 3. Ripley Hill Summit
At elevation of 1986 feet above sea level Ripley Hill is one of the highest points in Onondaga County and representative of the heavily scoured but relatively unreduced remnants of an essentially accordant preglacial summit surface. If pre-glacial summit accordance is accepted, the present departure from summit accordance affords a measure of summit reduction by glacial scour. Elongation of ridges commonly relates to ice-flow. Through valleys, long interpreted as showing a pattern inherited from pre-glacial stream systems, have recently been referred to as "intrusive troughs" implying only minor dependence on inherited pre-glacial controls.

Road parallels Cold Brook
The road parallels Cold Brook, a southward draining stream tributary to the Tioughnioga River.

STOP 4. Dwyer Park Gravel Pit
The upper 3 feet of stratified outwash has been interpreted on the basis of heavy mineral studies to represent the last or Valley Heads phase of Wisconsinan Glaciation while the lower approximately 8 feet of gravel represents the earlier Binghamton phase.

Mount Toppin
On the west side of the valley is Mount Toppin, which Von Engeln (1921) refers to as a truncated spur, the result of glacial scour. Holmes (1939) accounts for the over steepened appearance of
the east facing valley wall by differential insolation and therefore greater deposition on the east side of the valley .

STOP 5. Otisco Valley fan.
South of Preble is evidence that the ice tongue in Otisco Valley was active for a longer time than the ice in the Tully-Cortland trough. A fan was deposited by waters from Otisco Valley over the outwash from the Tully Moraine. Note that the southern part of the fan is a collapsed surface. Buried ice must have extended into the valley with melting and collapse in progress as glacial water was distributing the fan material.

Outwash materials of the Tully-Cortland trough
Continue north on Route 281 on the outwash materials of the Tully-Cortland trough. The road trends to the east side of the valley to skirt the Tully Lakes kame and kettle complex on the west side of the valley.

Tully Moraine
Proceed west onto the Tully Moraine, parallel to steep slope marking the proximal border of the moraine. Kettles are to be seen on both sides of the road.

STOP 6. Solvay Gravel Pit
Steep-walled gravel pit exposes materials composing major part of Tully moraine, showing it to be largely a product of outwash deposition from a stationary to narrowly oscillating ice margin. Exotic component in this through valley gravel is high with crystalline-carbonate-clastic ratios on the order of 10:40:50. The "bright" character of the gravels results from proximity to carbonate sources, attrition of diluting shale fraction from the lake plain, and effectiveness of glacial transport in a major through valley.
Query: How can we account for this ratio in view of the 5:15:80 ratio found at the Cortland kames?

Choker moraine
About 0.5 mile east of Tully cross low, smoothed valley choker moraine, convex eastward. This moraine may correlate with the "advance Valley Heads" position defined in Tully Valley by the outer border of the Tully Lakes area. If so, the smoothed nature of this ridge is puzzling, but may relate to impounding at the ice margin.

Valley Heads moraine
Near Markham Hollow Road enter Valley Heads moraine complex of Butternut trough. Proximal margin of moraine is less sharply defined than in Tully Valley. "Main Valley Heads" position is south of Apulia Station.

The Apulia-Fabius trough
The Apulia-Fabius trough extends eastward for several miles. Although segmented by drift deposits that define the heads of several drainage basins, this valley has the continuity suggestive of origin as part of a south-westward draining pre-glacial stream system.

Cross moraine ridge.
Cross moraine ridge. Toward axis of north-south through valley this ridge separates into three small but well-defined ridges marking recession of "advance Valley Heads" ice. The road follows a marginal meltwater channel between moraine ridge and valley wall.

Labrador Pond
Meltwater channel widens, opening onto outwash plain upon which shallow Labrador Pond is located. valley floor is less than 0.5 mile wide between 750 foot walls which converge southward as though toward a bedrock col. Labrador Pond, however drains southward by Labrador Creek on gradient developed by outwash deposition.
Query: How does the transverse relationship of the Apulia-Fabius trough and the Butternut-Labrador trough clarify the relative importance of inherited valley system as opposed to glacier scour in determining the through valley pattern of this part of the plateau?

Cross Shackham Brook.
State reforestation area and experimental drainage basin to east of route. Kame complex developed in valley wall re-entrant where Shackham Brook debouches into Labrador trough.

STOP 7. Truxton town highway department borrow pit.
Stratified sand and silt, with foreset beds and collapse structure. Dominance of shale in gravel, with small percent of crystallines and carbonates indicates dilution by uptake of local rock material. Rapid attrition of such material with fluvio-glacial sorting might within a few miles of through valley transportation "brighten" even this drab gravel, giving it a Binghamton-type lithology.

Truxton, birthplace of J.J McGraw
Truxton, birthplace of J.J McGraw, for 30 years manager of the New York Giants.

East Homer
Continue southwest through East Homer settled by Revolutionary War veteran John Albright in 1827. Route 13 lies along valley of East Branch Tioughnioga Creek, apparently a major tributary of the pre-glacial drainage line inferred to have extended west from Cortland toward Cayuga trough.

Kame terrace
Continue southwest past East River, on Route 13 toward Cortland. Coarse kame terrace gravels exposed in several pits in next three miles.
Note that the East Branch Tioughnioga Creek is diverted to the south side of the valley by the alluvial deposits of the south flowing tributaries. Since the recent floodplain deposits are generally less than eleven feet thick, the fan-shaped deposits are now being eroded and there is a general lack of new fan deposition, the East Branch Tioughnioga Creek must have been diverted by these fans shortly after the ice melted from the valley,

Esker parallels Route 13
Esker parallels Route 13 south of Light House Road where John Miller built first cabin in 1792.
Note that the East Branch Tioughnioga Creek is diverted to the south side of the valley by the alluvial deposits of the south flowing tributaries. Since the recent floodplain deposits are generally less than eleven feet thick, the fan-shaped deposits are now being eroded and there is a general lack of new fan deposition, the East Branch Tioughnioga Creek must have been diverted by these fans shortly after the ice melted from the valley,

STOP 8. Gravel pit in coarse till.
The till was part water-laid and there is outwash material at the south end of the cut.
Continue southwestward on Route 13 passing gravel pit with well stratified sediments on the right (N) in 0.9 miles.

West Branch of Tioughnioga Creek.
Draining the Tully-Horner-Cortland trough, this creek joins the East Branch of Tioughnioga Creek 0.5 miles east. The combined discharge drains south in a through valley with converging walls indicative of a pre-glacial divide a few
miles south of Cortland.

G: PALEONTOLOGY OF THE CORTLAND AREA
Jonathan W. Harrington
The University of Calgary
All of the exposures visited on this trip are in the Ithaca formation. The participant is referred to the discussion on benthic communities of the Geneseo Group (Trip A).

STOP 1. Roadcut on Rte 81, 3 miles south of Cortland
This exposure represents the Grammysia biotope in the Smethport depositional phase. Lithology is highly variable with shales, and ripple-marked and cross-laminated siltstones and fine sandstones. Coquinite lenses, especially with Cupularostrum, are frequent and usually show distinct size-sorting and differential accumulation of valves. Areas of high currents are dominated by the infaunal filter-feeder, Grammysia, and the byssally attached bivalve, Goniophora. Occasional vertical burrows may be seen.
Sheltered areas support an abundant epifauna of crinoids (Decadocrinus and Acanthocrinus) and occasional brachiopods. This environment is characterized by the accumulation of plant fragments and orthoconic cephalopods, and by the scavengers - the gastropods, Pleurotomaria several asteroids (Urasterella, Lepidasterella) and ophiuroids.
The orientation of many of the smaller crinoid calices (inverted with free arms outspread) indicates very slight water agitation. However the preservation of fragile specimens such as asteroids and the scyphomedusa, Plectodiscus cortlandensis, requires periodic rapid sedimentation. Fecal material is occasionally found at this outcrop. It has tentatively been identified as Tomaculum problematicum, a form not previously reported in North America.

STOP 2. Outcrop in Homer Gulf on Rte 41A.
Ponticeras perlatum has been identified from exposures in Homer Gulf. This places the section in the lower portion of the Ithaca format1on, probably correlative with the Renwick shale member in the Cayuga Lake meridian.
Lithology is extremely variable; consisting mainly of gray and reddish shales and siltstones. The fauna contains elements of both the Warrenella and Ithaca biotopes. Particularly common are: Conularia, Plumularia, Mucrospirifer, "Pugnoides", Cupularostrum eximia, Taxocrinus and linguloid brachiopods.

STOP 3. Small outcrop
Small outcrop on the west side of Cosmos Hill, 1 1/2 miles northwest of Cortland.
At this outcrop shales and fine siltstones of the Smethport phase are exposed. The fauna is that of the Leptodesma biotope, with abundant epifaunal filter-feeding faunas.

STOP 4. Roadcut on Rte 81 at Homer, Cortland Co.
The sequence here consists of alternating dark shales and fine siltstones, occasionally ripple-marked. The sparce fauna, representing the Leptodesma or Grammysia biotope, consists of rare brachiopods and occasional crinoids (Acanthocrinus). At several horizons are colonies of the hexactinellid sponge, Actinodictya placenta. These fragile forms were almost certainly preserved in situ.
Small hillside quarries immediately north of this exposure have yielded Ponticeras perlatum. Thus, indicating a correlation with the lower portion of the Ithaca (Renwick or Six Mile Creek Members) in the Ithaca meridian.

J: PROGLACIAL LAKE SEQUENCE IN THE TULLY VALLEY, ONONDAGA COUNTY
Thomas X. Grasso
Monroe Community College
Rochester, New York
Introduction
Few locations in the New York State display as varied an array of geological features as does the Tully Valley.
The Tully Valley is a glacially scoured trough carved into the northern margin of the Appalachian (Allegheny) Plateau (von Engeln, 1921). The glacial erosional and depositional features found here have been the subject of a number of theses and publications (Fairchild, 1909, 1932; von Engeln, 1921, 1959; Brainerd, 1922; Faltyn, 1957; Durham, 1958; Muller, 1964) .
Most of the valley lies within the outcrop belt of the Middle Devonian Hamilton Group. Unlike similar steep-sided troughs to the west, the Tully Valley does not now contain a finger lake. Because of the relatively low temporary base level, due to the absence of a lake, tributary streams have opened excellent exposures even in the lower formations of the Hamilton Group. East-west tributaries, in hanging valleys have carved deep, post-glacial, bedrock gorges, wherein the extremely fossiliferous Hamilton rocks are easily accessible. Therefore, the Tully Valley is also a highly stimulating region for the paleontologist and stratigrapher.
The purpose of this narrative is to outline the proglacial lake sequence of the Tully Valley as indicated by correlating the elevations of the delta masses deposited in these lakes with those of the abandoned outlet channels southeast of Syracuse.
This report is a compilation based mostly on the work of previous investigators and the examination of topographic maps. It should not be misconstrued as the final authoritative explanation of the apparently simple, but actually complex late Pleistocene history of the Tully Valley.

TRIP J PROGLACIAL LAKE SEQUENCE IN THE
TULLY VALLEY, ONONDAGA COUNTY

Kettles more numerous on west side.
Notice along the route that kettles are more numerous on the west side of the valley where a narrow bench can also be seen. Greater insolation and melting occurred along the east sides of valleys at the time of final deglaciation. The ice remained longer along the west valley wall where it was protected from the afternoon sun. Here the relatively thicker ice masses were finally buried to form Little York Lake, Crooked Lake and Song Lake.

Fan from Otisco Valley
In the Preble region, Interstate 81 crosses a fan deposited by a stream from Otisco Valley . Deposition of the fan crowded the West Branch Tioughnioga River against the east wall of the valley. These factors suggest that ice was active longer in Otisco Valley than in Onondaga Valley. Buried ice still existed in the valley so that melting and collapse were occurring while deposition continued from the northwest source.

STOP 1. Gravel Pit in Tully Moraine
Gatehouse Pond and Solvay Gravel Pit. Steep-walled gravel pit exposes materials composing major part of Tully moraine, showing it to be largely a product of outwash deposition from a stationary to narrowly oscillating ice margin. Exotic component in this through valley gravel is high with crystalline-carbonate-clastic ratios on the order of 10:40:50. The "bright" character of the gravels results from proximity to carbonate sources, attrition of diluting shale fraction from the lake plain, and effectiveness of glacial transport in a major through valley.

Cross Onondaga Creek
Cross Onondaga Creek which drops at Fellows Falls with hanging and barbed juncture into Onondaqa trough, in this area called Tully Valley. Ahead (NE), local relief exceeds 1250 ft. from upland to trough floor on proximal (northern) flank of massive Tully (Valley Heads) Moraine. The abrupt proximal border and gently graded distal slope of this moraine is characteristic of valley blocking moraine loops of this system on divides and northward opening valleys of central New York.
Seismic refraction profiles suggest that the unconsolidated valley fill in mid-trough opposite Fellows Falls may be 400 to 500 ft. thick, with the bedrock floor at 300 to 400 ft. msl. Northward, in the vicinity of Syracuse the bedrock floor of the trough lies below sea level. Southward the rock floor rises to 975 ft. above sea level in the col at Tully Lake.

Third Delta
Now riding over the surface of the third delta (el. 610') built into a lake whose outlet was the Rock Cut Channel.

Head of minor meltwater channel
Southwest of Joshua Corners note level swampy area at head of minor meltwater channel which deposited a delta complex into a predecessor of Otisco Lake, 3 miles to the southwest.

Cross Smith Hollow (Navarino Channel).
With threshold at 1005 ft. about one mile north of Rte. 20, the Navarino Channel developed as an outflow or overflow from Pumpkin Hollow (Lake Cedarvale) into Lake Marietta in Otisco trough

Four small marginal meltwater channels
Four small marginal meltwater channels notch the nose of Slate Hill to the west.

Pumpkin Hollow
Observe Pumpkin Hollow to the east (right). Cut sharply through Hamilton Shale section and floored on Onondaga Limestone. This is one of the largest of the cross channels which carried drainage eastward along the plateau margin. Pumpkin Hollow is about 0.25 miles wide and as much as 400 feet deep. Three miles east of Marcellus it widens abruptly to nearly a mile.

Head of Otisco Valley to Tully Valley channel
This is the head of the channel that carried the meltwaters from the Otisco Valley eastward into the Tully Valley. It becomes progressively wider eastward (downstream).

STOP 2. Sudden widening of valley
The sudden widening of the valley at this point, plus the absence of bedrock exposures in this area has led Krall (1966) to suspect that this is a buried pre-glacial or interglacial valley.

STOP 3. Gravel Pit Entrance.
This pit is being excavated in the second series of deltas (elev. approx. 700'). Shale pebbles occur frequently in the gravel and crossbedding is conspicuous.

Break in Slope on Makyes Road (S. Onondaga Hill Road)

STOP 4. Gravel Pit Entrance.
Gravel pit is in the second delta terrace. (Fairchild's Middle Terrace)

STOP 5. Base of tower.
Looking west can view the Tully Valley deltas just traversed. Also Joshua Coral Bed (Ludlowville Fm.) is exposed here.

Meltwater channel - Smoky Hollow with horseshoe shaped loop

Floor of Smoky Hollow meltwater channel (elev. 790').
East Syracuse reservoir on left.
Smoky Hollow, with bedrock floor just below 800 feet, is sharply incised in Hamilton Shales. This outlet may have controlled drainage of impounded waters in the Onondaga trough at the highest delta level in Cedarvale Channel (seen at STOP 3). Descend from drumlinized Hamilton upland onto channeled Onondaga bench.

STOP 6. Parking Area. Clarke Reservation Channel observed here.
Erosion by glacial meltwater, solution by underground water and joint control responsible for the features. Green Lake occupies the plunge basin cut into the Onondaga Limestone and underlying beds by waterfalls fed by glacial meltwater.

Entering Rock Cut Channel.
This steep-walled, flat-bottomed channel is floored by the Fiddlers Green Dolomite, with threshold at 550 feet at the west end and average eastward gradient of less than 10 feet per mile. The size of this channel and the configuration of the south wall suggest glacial advance south of Rock Cut Channel after the channel had attained essentially its present dimensions.

Note features in south wall (left side) of channel.

GEOLOGICAL STUDIES OFTHE NORTHWEST ADIRONDACKS REGION
FIELD TRIP GUIDE BOOK
THE NEW YORK STATE GEOLOGICAL ASSOCIATION
GEOLOGICAL STUDIES OF THE NORTHWEST ADIRONDACKS REGION
Field Trip Guidebook
43rd Annual Meeting
BRADFORD B. VAN DIVER
Editor
Department of Geological Sciences
State University of New York
College at Potsdam, New York
Published by the New York State Geological Association. Additional copies available from the Permanent Secretary, Dr. Philip C. Hewitt, Chairman, Department of Geology and Earth Science, State University of New York, College at Brockport, New York 14420.
PREFACE
On behalf of the Department of Geological Sciences of the State University of New York, College at Potsdam. I extend a most cordial welcome to all participants in the 43rd annual meeting of the New York State Geological Association.
The area to be covered by the six field trips of this guidebook lies in the northwestern part of New York State approximately enclosed by the St. Lawrence River and a line from Alexandria Bay to Gouverneur to Edwards to South Colton to Massena. The area lies entirely within St. Lawrence County with the exception of a small portion of Jefferson County . Regional physiographic and tectonic location is shown in Figure 1 of this Preface. Field trips are principally in the Adirondack Lowlands, the St. Lawrence Lowland and the Frontenac Axis. Major observable rock assemblages of the area are shown in the form of a generalized stratigraphic column in Figure 2. The column may help to orient the visitor to the Northwest Adirondack region.

A: SOME ASPECTS OF GRENVILLE GEOLOGY AND THE PRECAMBRIAN/PALEOZOIC UNCONFORMITY, NW ADIRONDACKS, NEW YORK
James D. Carl and Bradford B. Van Diver
State university of New York
College at Potsdam, New York
ABSTRACT
This field trip will cover some of the outstanding characteristics of Grenville geology in the Lowlands of the Northwest Adirondacks, with emphasis on both small and large-scale structures. Trip stops will be as follows : 1) "The Snake" roadcut near Canton, a plastically folded, weakly foliated marble with a thin, persistent, similarly folded layer composed chiefly of microcline; 2) The Rock Island roadcut near Gouverneur, which exposes cavity fillings of Potsdam Sandstone in Grenville marble, a trachytic(?) amygdaloidal dike intruding the marble, complex brecciation in gneisses and schists, numerous shear zones, and pyritic mineralization; 3) and 4) The Hyde "phacolith" near Brasie Corners where the relationship between minor and major structures will be stressed, and the controversial question of phacolith origin will be discussed; 5) The Hailesboro roadcut, exposing plastically deformed marble containing gabbroic blocks apparently derived from dikes; 6) The Poplar Hill migmatite roadcut in quartz-biotite-oligoclase gneiss, one of the most extensive metasedimentary rock types in the Grenville of this region; and 7) The Edwards roadcut, a well-known mineral collecting site for diopside, calcite, phlogopite, K-feldspar and apatite .

STOP 1. The "Snake"
(Figs. 1,2,3)-Large marble roadcut on new section of highway 11 about four miles southwest of Canton. This stop illustrates a remarkable example of the plastic deformation so common in the Grenville marbles. The bulk of the roadcut is coarse-grained calcite marble with minor diopside, tremolite, muscovite and quartz veins. The "Snake" shown in Fig. 3, is a nearly continuous thin band, generally less than six inches across, which traverses about half the length of the east side of the cut, and describes numerous sinuous folds. The snake is more segmented at the northern end and a good example of a refold can be seen. Compositional banding in the marble near the Snake is folded similarly with the Snake. Mineralogically, the Snake consists of microcline with minor sphene, calcite, biotite, and opaque. It is framed by a darker border zone consisting of calcite with abundant diopside, and minor sphene, biotite, opaque, quartz, actinolite, and tourmaline.
The writers believe the Snake and adjacent compositional bands represent original bedding. The Snake itself apparently derives from a thin but persistent bed of clay, such as an illite-chlorite mixture. Metamorphic reconstitution fixed the clay-derived potassium in microcline. The symmetrically distributed diopside marginal to the Snake indicates outward migration of SiO and Mg, and reaction with calcite to produce the diopside.

STOP 2. Rock Island Roadcut
Located about three miles north of Gouverneur on the Rock Island Road just south of the Oswegatchie River. Cut exposes cavity fillings of Potsdam sandstone in Grenville marble; structurally and stratigraphically complex, dravite-rich Precambrian rocks; numerous shear zones; an amygdaloidal trachyte dike, and pyritic mineralization.
The following are considered by the authors as evidence for cavity filling of Potsdam sand in marble at south end of cut, and smaller sandstone pockets in other parts of the cut:
1) Outcrop pattern (Fig. 4, 7). The quartzites here identified as outliers of the Potsdam Sandstone form irregular outcrop patterns which bear no consistent relationship to Precambrian structure. They have survived erosional stripping only where they fill deep solution pockets in the marbles.
2) Bedding attitudes (Figs. 4, 5). Gentle, inward-directed dips unrelated to compositional layering in the marble, which is generally steeply dipping and, in part, plastically folded. The inward-direction of dips is attributed
to compaction and slump. Cross-bedding is also present but not extensive.
3) Contacts (Figs. 5, 6, 7). Contacts with the marble are irregular and in part, dip steeply into the marble. They are characterized by breccias containing angular marble clasts derived by natural block caving of the marble by the contact, less conspicuous clasts of quartzites, schists, gneisses, and alaskites derived from Grenville lithologies (probably nearby), and some autoclastic fragments of Potsdam Sandstone. The large marble block shown in Fig. 6 appears to be a joint block which has fallen only a short distance into the sand. Release joints in the marble are sub-parallel to the contact on the other (western) side of the cut (Fig. 5). The matrix as a whole is poorly sorted quartz sand with extensive iron staining that diminishes away from the contact. Pyrite is also abundant in the quartzite near the contact, and it occurs sporadically throughout the roadcut in the marbles and in shear zones in various other rock types. Bedding is obscure near the contact at the main exposure at the south end of the cut, but becomes well-defined 20 to 30 feet into the quartzite. The quartzite also becomes cleaner and better sorted away from the contact. On the east side of the cut (Fig. 6, sample 6) the upper part of the quartzite near the contact appears to be a reworked regolith with weathered fragments of all kinds, a dirty appearance, and many voids. Thin quartzite seams occur within the main marble and in marble clasts.
4) Petrography. The cleaner, axial portion of the large quartzite body consists of moderately well-sorted quartzose sand with well-rounded, overgrown grains, with the overgrowths commonly iron-stained. A very common minor accessory, dravite, is rounded, often fractured, and similar to the dravite found in the numerous Grenville lithologies at the north end of the cut. It probably has been derived from them or from similar rocks. The sand becomes poorly sorted near the marble contact, more iron-stained, locally pyrite-rich, and contains many fragments of Grenville rocks with crystalloblastic dravite. Calcite is a common cement for sparse, widely-spaced sand grains near the marble contact (samples 4 and 5. Fig. 6). These grains have little or no overgrowth and are partly resorbed. Such features suggest a pH fluctuation at the time of deposition or cementation of the quartzite, leading to alternate solution and deposition of calcite and quartz.
5) Conical, cylindrical or bowl-shaped structures in the quartzite. These are found in many exposures of Potsdam Sandstone north and south of the St. Lawrence River. In the Rock Island roadcut, several are exposed on the upper surface of the large quartzite body, although they are not as well defined as in some areas of northern New York (Fig. 7). It is now generally agreed that these are slump structures formed when unconsolidated sand dropped into solution cavities in the underlying marble (Dietrich, 1953).
We conclude that the large quartzite body exposed in the Rock Island roadcut, and the smaller bodies of similar lithology at stations 3 and 12 (Fig. 5) are remnants of Potsdam Sandstone. The sand was deposited in solution cavities in marble developed during erosion of the Precambrian metamorphic terrain. Marble blocks collapsed and mingled with the unconsolidated sand, and sand filtered into joint seams and smaller solutional voids, some of which appear to be post-depositional. Post-depositional solution of the marble underlying the large quartzite body probably accounts for the fairly steep (30°) inward dip of the bedding.
There has long been controversy over the origin of the many isolated quartzite bodies which occur in the Grenville complex of northern New York. The question is whether they are outliers of Cambrian Potsdam Sandstone or part of the Grenville complex itself. Certainly some are part of the Grenville, or Pre-Grenville for that matter. But the mapping of Potsdam outliers as Grenville lithologies may lead to great confusion, and the distinction is therefore a very important one. Here are some observations summarized by J. S. Brown (1967) that characterize the Potsdam Sandstone of this region.
1) The number of recognized Potsdam remnants in New York is inversely proportional to the distance from the St. Lawrence River and to the depth of the tributary valley in which the remnant is found (Fig. 2 of Trip B). The land surface is higher and the tributary valleys are deeper progressively away from the St. Lawrence River, leading to the conclusion that the Paleozoic cover has been more efficiently removed in that direction. Nearer the river, the outliers merge into large sheets covering both valleys and uplands.
2) Potsdam sandstone which overlies gneiss or granite is commonly flat-lying, white and lightly cemented. Where it overlies marble it is much more variable in attitude, color and particle size. It is generally agreed that the pre-Potsdam surface was a near-perfect peneplain where developed on gneiss, (Fig. 3,4,5, of Trip B), but was an irregular and lower surface where developed on marble.
3) Slump structures, sandstone dikes, and cavity fillings are common in Potsdam Sandstone resting on marble. These features apparently represent post-depositional collapse of sand into underlying sinkholes prior to silicification (Dietrich 1953).
4) Bedding in the Potsdam generally truncates structures of the underlying Grenville rocks.
5) Sedimentary textures and structures are generally well-preserved because they postdate the Grenville orogeny. Metamorphic minerals in some outliers may be either, a) resistant detritals, or b) residues of solution
derived from the underlying marble.
R. O. Bloomer (1965) mapped quartzite bodies in the DeKalb area which he considers to be part of the Grenville complex. His primary evidence is that they protrude down into the marbles in apparent concordant structural relationship, and contain apparently crystalloblastic dravite, phlogopite, K-feldspar, tremolite, apatite, diopside, and talc which are also found in the enclosing metamorphic rocks. The massive bodies of this quartzite, however, are not recrystallized and retain sedimentary textures. Preservation of original texture is attributed to differences in composition and competency. The flowage of adjacent rocks around the quartzite during the Grenville Orogeny was such to cushion the relatively rigid quartzites and to prevent extensive recrystallization.
Trachyte(?) Dike (Fig. 5, Station 1O) -A dark green dike about 5 feet thick intrudes the marble in the central part of the roadcut. Thin sections were cut from seven samples located across the contact as shown in Fig. 5. Texturally the rock is fine grained, felted, and porphyritic. It is, however, almost entirely chloritized and zeolitized so that the original mineralogy cannot be determined. Phenocrysts are lath-shaped, euhedral, and the pseudomorphously preserved form and twinning is suggestive of sanidine. The rock is amygdaloidal, with amygdules primarily filled with chlorite. Color index ranges from about 5 to 25.
There is very little evidence of contact metamorphism, but there is a fine-grained, light green chill zone about one centimeter wide in places along the margins of the dike. Microscopic calcite veins are present in the dike and microscopic quartz veins occur in calcite adjacent to the contact. The distribution of tremolite, which is found in small quantities throughout the marble, appears unrelated to dike emplacement. In some parts of the contact there is a one-centimeter zone in which intrusive and marble are intimately interlayered parallel to the contact with numerous feather fractures in the dike material filled with calcite.
The dike clearly postdates the Grenville metamorphism. It was intruded in a rather viscous condition and the amygdaloidal character indicates a loss of volatile content at shallow depths of emplacement. Extensive hydrothermal alteration is indicated by chlorite and zeolite.
Metamorphic complex at north end of cut (Fig. 5, stations 6-9, 13) Because of its extreme complexity, this section of Fig. 5 is presented in a lithologically schematic manner. The exposure in general, consists of rather dark-colored,grey to purplish-brown rocks with a confusion of breccias, quartzites, gneisses, marble, albitite, a (Na) scapolitic rock, tremolite schist, and perhaps other lithologies, with northeasterly dipping foliation. In addition, the section is cut by numerous shear zones also dipping northeasterly. Additional shear zones are exposed at various localities up and down the river from here (Fig. 4). Fine-grained idioblastic dravite and some schorl(?), in measured amounts up to 25', is common to all of the rocks examined in thin section. Two breccia sections examined by the authors contain dravite-rich, angular clasts in a murky, highly oxidized crushed-rock matrix without dravite, indicating post-metamorphic brecciation.
The breccia problem here and elsewhere along the Oswegatchie River to the northeast and southwest, however, is not so simple. The writers are indebted to H. M. Bannerman (personal communication) for the following complex analysis.
Dr. Bannerman believes there are several types and several ages of breccias, in which some of the younger breccias appear to be superimposed upon the older.
"Many of the breccias exposed along the river in this part of the area appear to be autoclastic. The fragments in them are sharply angular and mineralogically composed of material similar to that of the matrix. Breccias of this kind are characteristically developed in, and in large measure restricted to the fine grained, dravite-bearing purplish-brown feldspar gneiss and its associated quartzites. In lateral distribution these particular breccias tend to parallel fold structures in the Grenville complex, and the brecciation is commonly accentuated along formational boundaries. Neither the mode nor the time of origin of these breccias has been precisely fixed. Conceivably they may not all have been formed in the same way or at the same time. They seem, however, to be Precambrian for at numerous points along the river breccias of this kind have been cut and re-crushed by the post-Precambrian faulting which has so profoundly affected the Grenville structures in this part of the area. In addition to these early breccias, various members of the Grenville assemblage throughout this area, superficially bear resemblance to skims and patches of fragmental rocks which I interpret as recomposed regolith. Area wise and bulk wise this type of material does not amount to much, but when imposed upon an older breccia it is both deceptive and confusing.
Briefly stated, this material is made up of a hodge-podge of angular to subrounded fragments of metamorphic rocks, similar to and presumably derived from the underlying formation. The matrix is a mixture of quartz and low to medium grade authigenic silicates, and sometimes calcite, an assemblage compositionally quite unlike the minerals found in the unaltered portions of the fragments or in the underlying, parent rock. As indicated, this type of structure is relatively uncommon, but when found it seems always to be at, or near the projected position of, the interface between the Precambrian erosion surface and the basal members of the Potsdam represented in this area. It seems reasonable, therefore, to believe that this particular type of breccia-like material represents remnants of a residual soil which had been developed on the Precambrian landscape prior to the advance of the Potsdam sea.
By far the more impressive of the breccias found in the belt along the river however, are the fault breccias that are associated with and presumably born of a system of faults which, in the vicinity of Rock Island Bridge, trend northeasterly, approximately parallel to the course of the river. The breccias associated with these faults run the gamut from huge to small jumbled blocks, embedded in a crushed matrix, to crumpled fissile schists, to gouge.
The fault system, with which these structures are associated, intersect each of the Precambrian rock units that outcrop in this part of the area. The major faulting, hence the associated breccia, is Post-Precambrian in age, though one cannot overlook the possibility that this particular zone was the scene of recurrent faulting throughout at least some of the Grenville orogeny, thus that displacements of more than one age may be represented here. But be this as it may, some of the Post-Precambrian breccia exposed in the Rock Island Bridge road cut, contain fragments of earlier formed breccia. Note, for example, the blocks of autoclastic feldspar gneiss, and thin bedded quartzite that are caught up in the shear zones exposed in the east face of the road cut, just south of the river.
Younger than any of the above mentioned types are, of course, the collapse breccias referred to in paragraph 2 of this letter. Collapse structures similar to those exposed in the Rock Island Bridge road cut are fairly common features along the margins of sandstone karst fillings all over this area. Presumably they are caused, in the main, by natural block caving, incident to solution of the marble along the walls of the sandstone, though in all likelihood this process may have been augmented by crustal readjustments following the removal of the continental glaciers.
In my judgment, therefore, the breccias along the river in the vicinity of Rock Island Bridge are the result of several different processes, imposed at widely different times, and that in some instances the current mess is the result of a recurrence of brecciation events.
And, as though this was not enough, the rock outcrops in this belt have also suffered a considerable amount of weathering subsequent to the disappearance of the glaciers. As a consequence many of the brecciated parts of the section are now heavily stained, and some are infiltrated by Pleistocene and recent sands, silts, mud, humus and what have you. All of which serves to further mask their identity, confuse the issue and make more difficult the task of unravelling the history of the breccias."

STOP 3. East central part of Hyde School Alaskite body
Near the intersection of two different directions of major folding. Amphibolite layers are isoclinally folded.
Petrography of the Hyde Alaskite Body
Preliminary petrographic studies have been made by the authors of samples collected from two east-west and two north-south traverses across the Hyde Alaskite body (Fig. 14). These are part of a sampling grid which is the basis for broader petrographic and x-ray fluorescent studies of relict stratigraphy presently in progress.
The preliminary studies indicate a fairly well-defined compositional layering which approximately follows the structure contours established independently from field data (Fig. 11). The rock types observed are the following:
Granitic Alaskite (number of samples-13)
Quartz Monzonitic Alaskitic Gneiss (3)
Granodioritic Trondhjemitic Gneiss (6)
Quartz Dioritic Trondhjemitic Gneiss (3)
Oligoclasic Gneiss (80% oligoclase) (1)
Biotite Leucodioritic Gneiss (4)
Dioritic Gneiss (1)
(Classification after Peterson, 1961)
All of these rock types, with the exception of the dioritic gneiss, are leucocratic, and distinction among them is based primarily on different proportions of a small number of principle rock-forming minerals: alkalic feldspar, plagioclase, quartz and accessory biotite and hornblende. The different proportions, however, are remarkably consistent in the samples studied as are the concomitant changes in character of the alkali feldspar and anorthite-content of the plagioclase. Of particular interest are the alaskites, trondhjemites and leucodiorites because their distribution gives the best indication of mappable compositional layering. A summary of their mineralogy follows :
Granitic Alaskite | Quartz Monz. Alaskitic Gneiss | Granodioritic Trondhjemitic Gneiss | Quartz Dioritic Trondhjemitic Gneiss | Leucodiorite
50- 70% stringy
microperthitic
or microantiperthitic
microcline
35- 40% cryptoperthitic
10- 20% cryptoperthitic
orthoclase
0-10% orthoclase,
slightly
perthitic
0-15%
2-15% plagioclase
An9-14
20-30% plagioclase
An17-25
50-70% plagioclase
An17-27
An20-29slight zoning
Note: Distinction between microcline and orthoclase is made by optical means only. Microcline is grid-twinned and has a large 2Vα Orthoclase appears untwinned in thin section and has a smaller 2Vα. Distinction by X-ray diffraction is in progress.
Mineralogical and textural differences, if correctly mapped, are suggestive of relict sedimentary stratigraphy. Other features which also point to a metasedimentary origin are the following:
1) Xenomorphic textures, an almost total lack of euhedral crystal forms
2) Replacement textures
3) Symplectites of biotite and quartz
4) Crystallization schistosity of biotite, hornblende and quartz
5) High quartz contents typical of many sediments but atypical of igneous rocks
6) Well-rounded and locally clustered zircons.

STOP 4. SW nose of Hyde School Alaskite body
The blunt, southwest-plunging nose of the Hyde School Alaskite body to observe the topographic contrast between alaskite and surrounding marble solution valley. Amphibolite layers here are ruptured and only slightly displaced, and pegmatite occurs within ruptures. A short downhill walk will show an outcrop of sillimanite-garnet gneiss marginal to the alaskite.

STOP 5. Hailesboro Roadcut
2011: The Guidebook calls this Stop 4, but maps it correctly as stop A5.
(Fig. 15)-Located on new section of Highway 58 near Hailesboro.
This cut exposes a large section of plastically folded marble with local clusters of black, predominantly rectangular, blocks of a gabbroic rock. The striking rectangularity of the blocks and their clustering, suggest that these were tabular bodies, probably dikes, which behaved in brittle fashion during deformation of the marble. The position of the blocks indicates that they were carried along with the marble and, to some extent, rotated.
Dike blocks near the marble contact consist of about 60% diopside, 20% meionitic scapolite, with about 5% each of microcline, sphene, and tremolite, and minor biotite, quartz, opaque, tourmaline and apatite. Contact with the marble is gradational with decreasing calc-silicate minerals, increasing quartz, and increasing carbonate progressing into the marble. Low-temperature alteration is very minor, and the mineral assemblages appear well adjusted to the metamorphic conditions. Cataclastic textures are almost totally absent. The reactions suggested by the mineralogy of the contact zone are :
3 Ca Al2Si2 O8 + CaCO3 → Ca4 Al6 Si6 O24 CO3
Anorthite + Calcite → Meionite
and, calcite + biotite → Microcline + diopside + CO2 + H2O
There is no plagioclase in the contact zones of the dike rocks examined, presumably because it has been completely replaced by meionite and by-products.
The observed characteristics indicate that the dike was either pre-or synmetamorphic, and there has been sufficient post-deformational recrystallization for complete mineralogical adjustment between the dike blocks and the marble.

STOP 6. Migmatitic Quartz-biotite-oligoclase Paragneiss
2011: The Guidebook calls this Stop 5, but maps it correctly as stop A6.
(Fig. 16) Located in a long roadcut through Poplar Hill on a new section of Highway 58 about one mile northwest of Fowler, New York. This cut exposes the migmatitic phase of the quartz-biotite-oligoclase paragneiss which in all its phases, comprises one of the second most abundant metasedimentary rock types in the Grenville series (second to the marble-see Fig.2). In general, the Grenville metasedimentary stratigraphic section consists approximately of 8000' of basal marble, overlain by 3000' of paragneiss, overlain by 4000' of marble with feldspathic quartzite near its top. The paragneiss has been studied in detail by Engel and Engel (1953). The exposure lies on the northwest side of the Sylvia Lake-Edwards syncline just north of a large body of Hermon-type porphyritic or porphyroblastic granitic gneiss (Brown and Engel, 1956, Fig. 1).
Description
The paragneiss here consists of a fine-grained grey-brown·gneiss with variable foliation, and with extensive lit-par-lit granitic veining. The veins vary from a few millimeters to several feet wide and those which parallel the foliation are extensively boudinaged. Transverse veins, especially thin ones, form intricate ptygmatic folds which apparently result from the combined effects of flowage, shear folding, compaction, and recrystallization. The veins are coarse-grained to pegmatitic, and white to red in color with the thicker veins commonly having white borders with red cores.
The average mineral composition of the presumably isochemical phases of this unit, here and elsewhere in northwestern New York, consists of about 40% quartz, 39% plagioclase (An25-35), 1% K-feldspar, and 17% green-brown biotite (Engel and Engel, 1953). Garnet is locally present at this outcrop, especially adjacent to granitic veins. Elsewhere the unit contains sillimanite. The veinous granite primarily consists of coarse-grained K-feldspar and quartz with variable but generally small amounts of highly-sericitized plagioclase and red-brown biotite. Replacement textures, especially of K-feldspar after green-brown biotite, are exceedingly common along vein margins.
Origin
The composition of presumed isochemical phases of the quartz-biotite-oligoclase paragneiss is closest to that of a graywacke (Engel and Engel, 1953). The formational environment of a graywacke, however, is one of minimal weathering with rapid transport and deposition, and this is anathema to the environment demanded by thick sections of thin-bedded persistent marbles and clean quartzites which lie conformably above and below the paragneiss. Shale is the more compatible sediment, but the paragneiss has an unusually high Na2O:K20 ratio (1:3) not found in normal shales
(Na2O:K2O typically about 0.4). A mode of origin suggested by Engel and Engel (1953) is one in which shale is chemically modified, either during deposition or diagenetically, so as to yield the relatively high Na-content, perhaps by interaction with salty Precambrian seawater.
Feldspathization
Presumed isochemical phases of the quartz-biotite-oligoclase paragneiss throughout the northwest Adirondacks typically lie in areas farthest from large bodies of alaskitic granite of the Hermon type (a type transitional to Hermon gneiss). Furthermore, all gradations appear to exist from the isochemical phase to veinous migmatites to Hermon gneiss to Hermon-type alaskite. The migmatitic phase exposed in the Poplar Hill roadcut characterizes the incipiently to moderately feldspathized and injected gneiss. The Hermon-type inequigranular gneiss which appears to represent a more extensively feldspathized phase, occurs in numerous large and small bodies within the paragneiss (Fig. 2). It typically contains large, often sieved, euhedral to subhedral grains of microcline.
The Hermon-type alaskitic end-member, an exposure of which may be found near Hyatt, N.Y., is relatively equigranular and directionless.
These features suggest progressive granitization of the paragneiss. Mineralogically, the progression involves a marked increase in K-feldspar, largely at the expense of biotite, and an increase in the albite-content of plagioclase without much change in plagioclase mode. Quartz also appears to decrease slightly, but not linearly.
One of the most significant chemical aspects of the progression is the change in the Na2O/K2O ratio from 1.3 to less than 1.

STOP 7. Edwards Roadcut
Brief stop if tine permits. This roadcut is well known to Mineral collectors in St. Lawrence County for green diopside, calcite of several colors, phlogopite, actinolite, apatite, molybdenite, pyrite and other sulfides and K-feldspar crystals.
This Irish green roadcut intersects one of several diopsidic marble units that are interlayered with feldspathic gneisses to the northwest of the outcrop face. These units are less than 100 feet thick with attitudes approximating N 50 E, 50 NW.
An outstanding feature here is the great quantity of green diopside, particularly in the form of coarse, well-parted crystals that extend into calcite veins. Contrast the occurrence of diopside here with that of Stop 1 southwest of Canton where the diopside is granular, disseminated within the marble, and partially a product of the reaction between marble and intrafolded silicic rock layers.
The outcrop consists chiefly of diopside except at the eastern edge of the roadcut where phlogopite-bearing marble with faint foliation can be seen. Megascopically, the diopside assumes several forms: (1) granular, green masses exclusive of marble, yet cut with calcite veinlets and with fine-grained, faintly foliated mica, (2) clusters or vein-like bladed diopside within granular diopside, and (3) large, parted crystals in the larger calcite veins typically oriented perpendicular to vein walls and surrounded more or less by gray calcite. Molybdenite, pyrite, phlogopite and apatite occur between diopside crystals. One molybdenite crystal collected here was 2 x 4 cm. in diameter and 2 mm. thick.
Diopside crystals measuring 2 feet 8 inches across in coarsely crystalline pink calcite masses were found with apatite and pyritohedral pyrite during road construction. Apatite crystals, 2 x 1/2 inches and doubly terminated with hexagonal bipyramids have also been reported in pink calcite.
Veins appear to be joint fillings by mobilized calcite accompanied by recrystallization of diopsidic host rock adjacent to the vein. Growth of crystals from the joint plane outward into the host rock is suggested in one vein. Note the vein with a sharp planar contact against granular diopsidic rock on one side (evidently the joint plane), and an irregular contact on the other side where coarse diopside crystals extend into the granular variety. In other veins, coarse diopside crystals extend only part way into the calcite matrix, and direction of growth appears to be inward toward the vein. Other diopside crystals are reported enclosed by marble with no apparent point of attachment.
Large diopside crystals show development of basal parting much better than cleavage, particularly where crystals extend into calcite matrix. Parting lamellae are generally of uniform thickness (about 2 mm) but may be wedge-shaped where crystals are bent (Fig. 17). Other crystals show lengthwise "feather" type parting, dividing the crystal into two unequal segments (Fig. 17). Broadly curved, concentrically parted segments are present in thicker diopside crystals.
Calcite is coarse, well cleaved, and shows pronounced color change from gray at vein margins in contact with diopside to pink toward the center of the vein. Gray calcite (by x-ray analysis) borders the larger diopside crystals (Fig. 17) and accentuates the margins of small veins. Bright orange calcite occurs on the hill behind the roadcut. It may occur as blotches of coarsely crystalline grains in a finer, lighter colored marble.
The hydrous minerals phlogopite and actinolite represent the more mobile, fluidized portion of vein filling. They are particularly abundant in the smaller veins or seams in granular diopside. Veins of calcite-phlogopite-pyrite-molybdenite (and other sulfides) extend outward from the larger joint fillings, and are usually devoid of diopside crystals. These veins contain phlogopite and pyrite which typically crowd the vein margins. Where the vein tapers to a thin seam, phlogopite is particularly abundant and the granular diopside host may be slightly discolored and impregnated with pyrite. Within the veins, pyrite is intergrown and often rimmed with an unidentified black metallic mineral. These smaller veins also have pink calcite cores and gray calcite margins.
Emplacement of hydrous minerals seems localized by foliation planes or tight joints. Actinolite occurs in clots or lenses, seemingly replacing the granular diopside host rock, but in crude alignment with the foliation. Or, the actinolite may occur as clots along calcite-phlogopite veinlets like knots in a rope. These clots vary from 1/2 to 2 inches in diameter and commonly consist of stubby, green, glassy actinolite crystals, phlogopite and pyrite. Coarse crystals of diopside, and perthitic K-feldspar (microcline?) occur several hundred feet northwest of the roadcut. The diopside and K-feldspar occur in aggregates enclosed by marble. Crystals often penetrate each other suggesting simultaneous growth of K-feldspar and diopside.

B: PRECAMBRIAN AND LOWER PALEOZOIC STRATIGRAPHY, NORTHWEST ST.LAWRENCE AND NORTH JEFFERSON COUNTIES, NY
William Kirchgasser,
The State University College at Potsdam
Potsdam, New York
George Theokritoff
Rutgers University
Newark, New Jersey
ABSTRACT
The field trip is designed to demonstrate general features of the lower Paleozoic sequence with emphasis on the stratigraphic relations with the Precambrian basement and environments of deposition. The strata form part of a complex upper Cambrian-Lower Ordovician transgressive sequence that blankets an erosion surface on the Precambrian of low but variable relief. Basal quartzose sandstones (Potsdam Sandstone), with local conglomerate and breccia, grade and inter-tongue seaward (eastward) through calcareous and dolomitic sandstones and sandy dolomites (Theresa and Bucks Bridge Formations) into purer dolomites in the Champlain Valley. In St. Lawrence County, the Theresa and the Bucks Bridge Formations are overlain by dolomites and sandy dolomites (Ogdensburg Dolomite). Sedimentological and paleontological features (particularly trace fossils and algal stromatolites) will be seen that document and refine the general interpretation of the various facies as shallow water shelf deposits.
The excursion is divided into Saturday and Sunday morning parts (Fig. 1). The Saturday trip begins with a brief examination of the complex flow folding in the Grenville marbles south of Canton followed by examination of outliers of Potsdam Sandstone within the marbles north of Gouverneur, in an area where there have been problems in the differentiation of Paleozoic and Precambrian quartzites and breccias. Lunch will be in a park at Alexandria Bay, overlooking the Thousand Islands; here we will discuss the influence of the Frontenac Axis on the distribution of the Paleozoic rocks.
In the afternoon, the trip continues at an excellent exposure of an angular unconformity between the Potsdam Sandstone and Precambrian metasedimentary rocks just east of Alexandria Bay. We will then proceed down the St. Lawrence valley and examine in stratigraphic succession 1). the Potsdam Sandstone and lower Theresa Formation near Chippewa Bay, 2). the Theresa Formation near Brier Hill and 3). the Ogdensburg Dolomite at Ogdensburg.
The localities to be visited on Sunday are 1). the Allens Falls Fanglomerate or "basal breccia" at Allens Falls, 2). the type exposure of the Potsdam Sandstone at Hannawa Falls and 3). the dendroid graptolite locality in the Bucks Bridge Formation near Madrid described by Berry and Theokritoff (1966).

STOP 2. Rock Island Roadcut
Located about three miles north of Gouverneur on the Rock Island Road just south of the Oswegatchie River. Cut exposes cavity fillings of Potsdam sandstone in Grenville marble; structurally and stratigraphically complex, dravite-rich Precambrian rocks; numerous shear zones; an amygdaloidal trachyte dike, and pyritic mineralization.
The following are considered by the authors as evidence for cavity filling of Potsdam sand in marble at south end of cut, and smaller sandstone pockets in other parts of the cut:
1) Outcrop pattern (Fig. 4, 7). The quartzites here identified as outliers of the Potsdam Sandstone form irregular outcrop patterns which bear no consistent relationship to Precambrian structure. They have survived erosional stripping only where they fill deep solution pockets in the marbles.
2) Bedding attitudes (Figs. 4, 5). Gentle, inward-directed dips unrelated to compositional layering in the marble, which is generally steeply dipping and, in part, plastically folded. The inward-direction of dips is attributed
to compaction and slump. Cross-bedding is also present but not extensive.
3) Contacts (Figs. 5, 6, 7). Contacts with the marble are irregular and in part, dip steeply into the marble. They are characterized by breccias containing angular marble clasts derived by natural block caving of the marble by the contact, less conspicuous clasts of quartzites, schists, gneisses, and alaskites derived from Grenville lithologies (probably nearby), and some autoclastic fragments of Potsdam Sandstone. The large marble block shown in Fig. 6 appears to be a joint block which has fallen only a short distance into the sand. Release joints in the marble are sub-parallel to the contact on the other (western) side of the cut (Fig. 5). The matrix as a whole is poorly sorted quartz sand with extensive iron staining that diminishes away from the contact. Pyrite is also abundant in the quartzite near the contact, and it occurs sporadically throughout the roadcut in the marbles and in shear zones in various other rock types. Bedding is obscure near the contact at the main exposure at the south end of the cut, but becomes well-defined 20 to 30 feet into the quartzite. The quartzite also becomes cleaner and better sorted away from the contact. On the east side of the cut (Fig. 6, sample 6) the upper part of the quartzite near the contact appears to be a reworked regolith with weathered fragments of all kinds, a dirty appearance, and many voids. Thin quartzite seams occur within the main marble and in marble clasts.
4) Petrography. The cleaner, axial portion of the large quartzite body consists of moderately well-sorted quartzose sand with well-rounded, overgrown grains, with the overgrowths commonly iron-stained. A very common minor accessory, dravite, is rounded, often fractured, and similar to the dravite found in the numerous Grenville lithologies at the north end of the cut. It probably has been derived from them or from similar rocks. The sand becomes poorly sorted near the marble contact, more iron-stained, locally pyrite-rich, and contains many fragments of Grenville rocks with crystalloblastic dravite. Calcite is a common cement for sparse, widely-spaced sand grains near the marble contact (samples 4 and 5. Fig. 6). These grains have little or no overgrowth and are partly resorbed. Such features suggest a pH fluctuation at the time of deposition or cementation of the quartzite, leading to alternate solution and deposition of calcite and quartz.
5) Conical, cylindrical or bowl-shaped structures in the quartzite. These are found in many exposures of Potsdam Sandstone north and south of the St. Lawrence River. In the Rock Island roadcut, several are exposed on the upper surface of the large quartzite body, although they are not as well defined as in some areas of northern New York (Fig. 7). It is now generally agreed that these are slump structures formed when unconsolidated sand dropped into solution cavities in the underlying marble (Dietrich, 1953).
We conclude that the large quartzite body exposed in the Rock Island roadcut, and the smaller bodies of similar lithology at stations 3 and 12 (Fig. 5) are remnants of Potsdam Sandstone. The sand was deposited in solution cavities in marble developed during erosion of the Precambrian metamorphic terrain. Marble blocks collapsed and mingled with the unconsolidated sand, and sand filtered into joint seams and smaller solutional voids, some of which appear to be post-depositional. Post-depositional solution of the marble underlying the large quartzite body probably accounts for the fairly steep (30°) inward dip of the bedding.
There has long been controversy over the origin of the many isolated quartzite bodies which occur in the Grenville complex of northern New York. The question is whether they are outliers of Cambrian Potsdam Sandstone or part of the Grenville complex itself. Certainly some are part of the Grenville, or Pre-Grenville for that matter. But the mapping of Potsdam outliers as Grenville lithologies may lead to great confusion, and the distinction is therefore a very important one. Here are some observations summarized by J. S. Brown (1967) that characterize the Potsdam Sandstone of this region.
1) The number of recognized Potsdam remnants in New York is inversely proportional to the distance from the St. Lawrence River and to the depth of the tributary valley in which the remnant is found (Fig. 2 of Trip B). The land surface is higher and the tributary valleys are deeper progressively away from the St. Lawrence River, leading to the conclusion that the Paleozoic cover has been more efficiently removed in that direction. Nearer the river, the outliers merge into large sheets covering both valleys and uplands.
2) Potsdam sandstone which overlies gneiss or granite is commonly flat-lying, white and lightly cemented. Where it overlies marble it is much more variable in attitude, color and particle size. It is generally agreed that the pre-Potsdam surface was a near-perfect peneplain where developed on gneiss, (Fig. 3,4,5, of Trip B), but was an irregular and lower surface where developed on marble.
3) Slump structures, sandstone dikes, and cavity fillings are common in Potsdam Sandstone resting on marble. These features apparently represent post-depositional collapse of sand into underlying sinkholes prior to silicification (Dietrich 1953).
4) Bedding in the Potsdam generally truncates structures of the underlying Grenville rocks.
5) Sedimentary textures and structures are generally well-preserved because they postdate the Grenville orogeny. Metamorphic minerals in some outliers may be either, a) resistant detritals, or b) residues of solution
derived from the underlying marble.
R. O. Bloomer (1965) mapped quartzite bodies in the DeKalb area which he considers to be part of the Grenville complex. His primary evidence is that they protrude down into the marbles in apparent concordant structural relationship, and contain apparently crystalloblastic dravite, phlogopite, K-feldspar, tremolite, apatite, diopside, and talc which are also found in the enclosing metamorphic rocks. The massive bodies of this quartzite, however, are not recrystallized and retain sedimentary textures. Preservation of original texture is attributed to differences in composition and competency. The flowage of adjacent rocks around the quartzite during the Grenville Orogeny was such to cushion the relatively rigid quartzites and to prevent extensive recrystallization.
Trachyte(?) Dike (Fig. 5, Station 1O) -A dark green dike about 5 feet thick intrudes the marble in the central part of the roadcut. Thin sections were cut from seven samples located across the contact as shown in Fig. 5. Texturally the rock is fine grained, felted, and porphyritic. It is, however, almost entirely chloritized and zeolitized so that the original mineralogy cannot be determined. Phenocrysts are lath-shaped, euhedral, and the pseudomorphously preserved form and twinning is suggestive of sanidine. The rock is amygdaloidal, with amygdules primarily filled with chlorite. Color index ranges from about 5 to 25.
There is very little evidence of contact metamorphism, but there is a fine-grained, light green chill zone about one centimeter wide in places along the margins of the dike. Microscopic calcite veins are present in the dike and microscopic quartz veins occur in calcite adjacent to the contact. The distribution of tremolite, which is found in small quantities throughout the marble, appears unrelated to dike emplacement. In some parts of the contact there is a one-centimeter zone in which intrusive and marble are intimately interlayered parallel to the contact with numerous feather fractures in the dike material filled with calcite.
The dike clearly postdates the Grenville metamorphism. It was intruded in a rather viscous condition and the amygdaloidal character indicates a loss of volatile content at shallow depths of emplacement. Extensive hydrothermal alteration is indicated by chlorite and zeolite.
Metamorphic complex at north end of cut (Fig. 5, stations 6-9, 13) Because of its extreme complexity, this section of Fig. 5 is presented in a lithologically schematic manner. The exposure in general, consists of rather dark-colored,grey to purplish-brown rocks with a confusion of breccias, quartzites, gneisses, marble, albitite, a (Na) scapolitic rock, tremolite schist, and perhaps other lithologies, with northeasterly dipping foliation. In addition, the section is cut by numerous shear zones also dipping northeasterly. Additional shear zones are exposed at various localities up and down the river from here (Fig. 4). Fine-grained idioblastic dravite and some schorl(?), in measured amounts up to 25', is common to all of the rocks examined in thin section. Two breccia sections examined by the authors contain dravite-rich, angular clasts in a murky, highly oxidized crushed-rock matrix without dravite, indicating post-metamorphic brecciation.
The breccia problem here and elsewhere along the Oswegatchie River to the northeast and southwest, however, is not so simple. The writers are indebted to H. M. Bannerman (personal communication) for the following complex analysis.
Dr. Bannerman believes there are several types and several ages of breccias, in which some of the younger breccias appear to be superimposed upon the older.
"Many of the breccias exposed along the river in this part of the area appear to be autoclastic. The fragments in them are sharply angular and mineralogically composed of material similar to that of the matrix. Breccias of this kind are characteristically developed in, and in large measure restricted to the fine grained, dravite-bearing purplish-brown feldspar gneiss and its associated quartzites. In lateral distribution these particular breccias tend to parallel fold structures in the Grenville complex, and the brecciation is commonly accentuated along formational boundaries. Neither the mode nor the time of origin of these breccias has been precisely fixed. Conceivably they may not all have been formed in the same way or at the same time. They seem, however, to be Precambrian for at numerous points along the river breccias of this kind have been cut and re-crushed by the post-Precambrian faulting which has so profoundly affected the Grenville structures in this part of the area. In addition to these early breccias, various members of the Grenville assemblage throughout this area, superficially bear resemblance to skims and patches of fragmental rocks which I interpret as recomposed regolith. Area wise and bulk wise this type of material does not amount to much, but when imposed upon an older breccia it is both deceptive and confusing.
Briefly stated, this material is made up of a hodge podge of angular to subrounded fragments of metamorphic rocks, similar to and presumably derived from the underlying formation. The matrix is a mixture of quartz and low to medium grade authigenic silicates, and sometimes calcite, an assemblage compositionally quite unlike the minerals found in the unaltered portions of the fragments or in the underlying, parent rock. As indicated, this type of structure is relatively uncommon, but when found it seems always to be at, or near the projected position of, the interface between the Precambrian erosion surface and the basal members of the Potsdam represented in this area. It seems reasonable, therefore, to believe that this particular type of breccia-like material represents remnants of a residual soil which had been developed on the Precambrian landscape prior to the advance of the Potsdam sea.
By far the more impressive of the breccias found in the belt along the river however, are the fault breccias that are associated with and presumably born of a system of faults which, in the vicinity of Rock Island Bridge, trend northeasterly, approximately parallel to the course of the river. The breccias associated with these faults run the gamut from huge to small jumbled blocks, embedded in a crushed matrix, to crumpled fissile schists, to gouge.
The fault system, with which these structures are associated, intersect each of the Precambrian rock units that outcrop in this part of the area. The major faulting, hence the associated breccia, is Post-Precambrian in age, though one cannot overlook the possibility that this particular zone was the scene of recurrent faulting throughout at least some of the Grenville orogeny, thus that displacements of more than one age may be represented here. But be this as it may, some of the Post-Precambrian breccia exposed in the Rock Island Bridge road cut, contain fragments of earlier formed breccia. Note, for example, the blocks of autoclastic feldspar gneiss, and thin bedded quartzite that are caught up in the shear zones exposed in the east face of the road cut, just south of the river.
Younger than any of the above mentioned types are, of course, the collapse breccias referred to in paragraph 2 of this letter. Collapse structures similar to those exposed in the Rock Island Bridge road cut are fairly common features along the margins of sandstone karst fillings all over this area. Presumably they are caused, in the main, by natural block caving, incident to solution of the marble along the walls of the sandstone, though in all likelihood this process may have been augmented by crustal readjustments following the removal of the continental glaciers.
In my judgment, therefore, the breccias along the river in the vicinity of Rock Island Bridge are the result of several different processes, imposed at widely different times, and that in some instances the current mess is the result of a recurrence of brecciation events.
And, as though this was not enough, the rock outcrops in this belt have also suffered a considerable amount of weathering subsequent to the disappearance of the glaciers. As a consequence many of the brecciated parts of the section are now heavily stained, and some are infiltrated by Pleistocene and recent sands, silts, mud, humus and what have you. All of which serves to further mask their identity, confuse the issue and make more difficult the task of unravelling the history of the breccias."

STOP 3. Scenic View Park, Alexandria Bay, New York.
Lunch Stop; leuco-granitic (alaskitic) gneiss; Frontenac Axis.
The Frontenac Axis is a narrow southeastward extension of the Canadian Shield connecting the Laurentian Plateau with the "Lowlands" region of the Adirondack Mountains. This terrane of resistant Precambrian crystalline rocks forms the Thousand Islands where the axis is crossed by the postglacial St. Lawrence River a few miles from where the river spills out of Lake Ontario.
In the Thousand Islands area, the basement rocks are a highly folded and intensely metamorphosed complex of metamorphic rocks dominated by pink or red leucogranitic (alaskitic) gneiss (Alexandria Granite; Rockport-type granite in Canada) with white metaquartzites and a variety of layered gneisses; the sequence is broadly monoclinal, with a northwesterly dip (Wynne-Edwards, 1959, 1962, 1963).
The axis separates the lowermost Paleozoic strata of the Ottawa-St. Lawrence Lowland to the northeast from the similar but less complete succession of the Ontario Lowland to the southwest. It is difficult to document the influence of the axis on early Paleozoic sedimentation because of the scarcity of outcrop in the immediate area (Fig. 2). Numerous outliers of the Potsdam Sandstone (Nepean in Canada) and a few of the Theresa Formation indicate that the axis was covered by a westward-transgressing sea during Late Cambrian-Early Ordovician (Early Canadian) time. In the St. Lawrence Valley, the sandstones and dolomites of the Theresa-Bucks Bridge Formations (March Formation in Canada) are succeeded by the Ogdensburg Dolomite (Oxford Formation in Canada) of Medial and Late Canadian age; the Ogdensburg Dolomite is unconformably overlain by a Middle Ordovician limestone sequence of Chazyan (Rockcliff and St. Martin Formations) and Mohawkian (Ottawa Formation) age (Fisher 1968, p. 29).
West of the Frontenac Axis, the Ogdensburg Dolomite and Chazyan limestones are missing and here the limestone sequence of Mohawkian age (Black River and Trenton Groups) rests unconformably on the Theresa Formation and older rocks. The Black River and Trenton limestones were deposited in a transgressing sea that crossed the Frontenac Axis and entered the Ottawa-St. Lawrence basin from the southwest (Wilson, 1946, p. 7). There is no indication of later Paleozoic sedimentation over the axis. Any deposits that may have accumulated have since been removed by post-Ordovician erosion that has stripped the lower Paleozoic sequence away from the crest to leave a sequence of stair-like terraces and scarps.
Glacial deposits are rare and thin in the Alexandria Bay area and the Precambrian and Paleozoic rock display evidence of glacial erosion, especially on the Potsdam Sandstone. The features include glacial polishing, striae and grooves (direction to SW about parallel to the St. Lawrence River) and chatter marks (MacClintock and Stewart, 1965, p. 120).

STOP 4. Precambrian-Paleozoic angular unconformity at Alexandria Bay.
Roadcut on N. Y. 12, 2 miles east of Alexandria Bay, N.Y.
The east end of the roadcut exposes a knoll on the pre-Potsdam erosion surface formed on steeply inclined to vertical Precambrian metasedimentary rocks which are overlapped by nearly horizontal orthoquartzites of the Potsdam Sandstone (Figs. 3-5). The Precambrian rocks include medium-grained leucogranitic (alaskitic) gneiss which form resistant masses at the west and east ends of the outcrop. Between these rocks are darker layered gneisses, including red and pink leuco-quartz diorites, pink alaskitic gneiss and green and white diopsidic quartz diorites. The layered gneisses are mostly highly altered, especially in the intensely weathered zone in the first few feet below the erosion surface.
The basal Potsdam Sandstone is well bedded, medium-and thick-bedded, medium-grained, white orthoquartzite. The basal part of the sandstone sequence thins over the crest of the knoll, as the lowermost beds pinch out against the erosion surface. The quartz grains are mostly well rounded, highly spherical, and frosted and are thoroughly cemented by silica overgrowths in optical continuity with the grains, a feature for which the Potsdam Sandstone has long been noted. Cross-and horizontal laminae within the beds are defined by minor fluctuations in grain size from very fine-to coarse-grained texture and accessary mineral content. Heavy minerals are generally rare throughout the orthoquartzite facies of the Potsdam Sandstone; in this area tourmaline and zircon are the most common.
Above the basal strata the beds become more nearly horizontal and the bed thickness gradually decreases (medium-bedded). The beds include red, pink and white laminated, medium-grained orthoquartzite with conspicuous "dusty" hematite rimming the rounded quart grains. Similar, but less mature, friable, white, gray and pink, fine-to medium-grained orthoquartzites also occur which weather greenish-yellow. Tourmaline and hematite are conspicuous in these rocks, along with interstitial clay and occasional rock fragments. The red and pink "banded" sandstones continue to the top of the section. In the upper third of the section is a well defined band of large-scale, planar cross-stratified beds.
The high textural and mineralogical maturity and the absence of clasts of the Precambrian rocks in the lowermost beds suggests that the sediments described above were derived from reworking of fluvial sands (floodplain alluvium) by an encroaching sea. The detrital material carried seaward by currents accumulated on and eventually blanketed the irregular pre-Potsdam erosion surface. Sedimentary features in the sandstones (especially the laminated bedding) indicate deposition in the "low energy, littoral to nearshore environment" of the Potsdam Sandstone described by Otvos (1966); Fisher (1968, p. 16) interprets what appears to be a similar facies of the Potsdam Sandstone in the Champlain valley as, in part, the deposits of low energy outer intertidal and inner subtidal environments. The cross-stratified beds in the upper part of the section may indicate somewhat higher-energy conditions in which currents built solitary banks into shallow water just off a beach (Allen, 1963, p. 101).

STOP 5. Chippewa Bay.
Upper Potsdam Sandstone and lower Theresa Formation exposed in roadcut on N.Y. 12, 0.2 miles northeast of intersection with Pleasant Valley Road, 2.7 miles east of Chippawa Bay, New York.
Potsdam Sandstone
The Potsdam Sandstone exposed at this locality is a thin-to medium-bedded, white orthoquartzite with minor cross-stratification and ripple marks, especially in the lower part of the section (Fig. 6). Vertical U-shaped organismal burrows (Diplocraterion?) occur in Horizon 5-1 (Stop 5, Horizon 1) and are well displayed in the southeastern wall at the southwestern end of the roadcut (Fig. 8). Simple vertical burrows are also seen at this level but these are believed to be U-shaped burrows that are only partly displayed by the available section.
Close examination shows that the burrows are Spreitenbauten (Seilacher, 1967, p. 418-421) as they display laminations reflecting the shape of the terminal bend that are indicative of a shift of the tube through the sediment. Some of the burrows are infilled and the infilling can be traced into the lowest part of the burrows; the burrows appear to be entirely protrusive in vertical direction and thus reflect a response to growth of the organism rather than a response to fluctuations in the depositional rate (Seilacher, 1967, p. 418-420). The rather deep penetration of the burrows at this horizon indicates a slowing down of the rate of sedimentation.
The organism that made these burrows can be postulated as an elongate animal that depended on the development of incurrent and excurrent water movements. It was thus a suspension feeder and its burrow a protective shelter. Currents above the sediment-water interface had sufficient turbulence to transport food particles and keep them in suspension, but not enough to introduce a significant amount of sediment or cause significant erosion. Such burrows are known from modern intertidal and shallow subtidal environments as well as more off-shore areas (Seilacher, 1967; Frey, 1970), and are made by a variety of organisms : amphipod crustaceans (Seilacher, 1967, p. 414, 422), polychaete annelids (Seilacher, 1967, p. 414; Rhoades, 1967, p. 464-467; Frey, 1970, p. 512-513) and hemichordates (Frey, 1970, p. 512). Studies by Rhoades (1967) and Seilacher (1967) indicate that deep burrows are generally characteristic of intertidal environments, in which the burrows provide shelter from fluctuations in temperature, salinity and dessication at the sediment-water interface. Such conditions might account for the relatively low density of burrows and the apparent absence of other fossils in Horizon 5-1 and elsewhere in the section. It thus seems a reasonable hypothesis that the white orthoquartzite facies of the Potsdam Sandstone in this area records a nearshore intertidal environment.
Theresa Formation.
The lower Theresa Formation in this section consists of gray and blue-gray, fine-grained, feldspathic, calcareous and dolomitic sandstone. The original sedimentary fabric of the rock has been modified to varying degrees by burrowing and general bioturbation. Remarkably well rounded, spherical, medium-and coarse-grained quartz is scattered throughout the succession. The carbonate cement, which locally approaches 50% of the rock, is predominantly calcite which appears to have largely replaced an earlier dolomite cement. Locally the detrital grains float in a matrix of sparry calcite, forming the distinctive lustrous cleavage surfaces ("sand crystals" or "crystal sandstone") noted by early workers (Cushing and others, 1910; Cushing, 1916). The quartz grains, which appear frosted in hand specimen, are etched and corroded by the calcareous cement; siliceous overgrowths similar to those which characterize the underlying Potsdam Sandstone occur where the quartz grains are concentrated.
Relatively shallow vertical and nearly vertical burrows (Skolithos) infilled with calcite-cemented quartz are well displayed in Horizon 5-5. Lenses and lamellae of comminuted inarticulate brachiopod debris (Lingulepis acuminatus) are concentrated at several levels in the lowermost horizons; the best material may be collected from Horizons 5-5 and 5-6 on the north side of the roadcut. Poorly preserved discoidal gastropods and grazing trails may be seen on some bedding surfaces in Horizon 5-4.
The immaturity of these sandstones and their carbonate content and fauna indicate accumulation in a relatively uniform low energy environment (possibly subtidal), offshore from the intertidal environment suggested for the underlying white orthoquartzites of the Potsdam Sandstone.

STOP 6. Brier Hill
Roadcut along N. Y. 12, just south of turnoff to Brier Hill and Jacques-Cartier State Park. Theresa Formation.
The outcrop exposes a gently folded and faulted section in the upper part of the Theresa Formation (Fig. 7) consisting of medium-grained, white orthoquartzites alternating with gray and blue-gray, coarse-, medium-and fine-grained, calcareous and dolomitic sandstones. The white orthoquartzites are like those of the upper Potsdam Sandstone seen at Stop 5. At Horizons 6-3 and 6-7, the quartzites are riddled with dark brown mottles and elongate patches of limonite-stained quartz floating in sparry calcite cement. These features trend nearly parallel to bedding surfaces and are interpreted as infillings of burrows.
The gray calcareous and dolomitic sandstones are thoroughly bioturbated (mottled) and original sedimentary fabrics have been nearly obliterated. Cut-and-fill structure may be seen at several levels, indicating relatively strong current activity. The rock consists of a mixture of about equal amounts of coarse-, medium-and fine-grained quartz, the coarser grains being remarkably well rounded, spherical, and frosted. The grains are notably etched and corroded by the predominantly calcitic cement, but optically conformable silica overgrowths occur where quartz grains are concentrated. The calcite appears to have almost completely replaced an earlier dolomite cement and the lustrous cleavage surfaces produced by pockets of sparry calcite cement (crystal sandstone) are a distinctive feature of the rock in the field (Horizons 6-2, 6-6). Inarticulate debris, detrital feldspar and rock fragments are less conspicuous in the Theresa Formation at this locality than at Stop 5.
The relatively thorough bioturbation of the gray and blue-gray calcareous and dolomitic sandstones (Horizons 6-2, 6-4, 6-6) again suggests that the sediments accumulated in a more offshore (subtidal) environment than that of the less biogenically disturbed orthoquartzites. Moore and Scrutton (1957) and Rhoades (1967) have noted that prolonged activity of subtidal bottom communities near the sediment-water interface under conditions of relatively slow sediment accumulation results in the complete reworking of the sediment.
Cushing (1916, p. 24) reported about 140 feet of Theresa Formation in this area and Dietrich (1957, p. 706) documented the variation in lithofacies within the unit. In addition to the types described above, Dietrich reported blue-gray, sandy limestones and buff and gray, sandy, dolomitic limestones. Chadwick (1915, p. 289) introduced the name Heuvelton Sandstone for a 0 to 20 foot thick lens of white orthoquartzite lying above the Theresa mixed beds in central St. Lawrence County. Although Cushing (19l6) used the name, the presence of the unit among the white orthoquartzites in the Brier Hill area is uncertain (Dietrich, 1957, p. 105). As noted above, Berry and Theokritoff (1966) regard the Heuvelton Sandstone as a member of their extended Bucks Bridge Formation. Although the Theresa Formation (northwesternmost St. Lawrence and Jefferson Counties) and the Bucks Bridge Formation (central St. Lawrence county) of Berry and Theokritoff (1966) occupy the interval between the Potsdam Sandstone and the Ogdensburg Dolomite, their precise stratigraphic relationships have yet to be established.

STOP 7. McConville, Inc. Quarry in Ogdensburg Dolomite on the west side of Ogdensburg.
Driving east on N.Y. 37 from Morristown, N.Y. turn left at the Ogdensburg bypass and follow the sign for downtown Ogdensburg. Continue on old N.Y. 37 for 0.8 miles and turn right at the fork onto Ogden Street. Proceed for two blocks and turn right onto Madison Avenue. Park in field opposite intersection with Gates Street (0. 1 miles). Ogdensburg Dolomite.
Cushing (1916) recognized around 140 feet of Ogdensburg Dolomite in this region and measured sections from roadcuts and quarries (now mostly overgrown) between Morristown and Ogdensburg and northward to Red Mills, New York. In spite of scattered outcrop and apparent rapid facies changes, he pieced together the composite section summarized here, beginning at the base: 1. small thickness of basal sandy beds transitional with the underlying Theresa Formation 2. thick-bedded, blue, sandy dolomites (15 ft.) and thin-bedded, gray dolomites (20 ft.) 3. alternating thick-bedded, dark blue and gray, sandy dolomites, locally with abundant but poorly preserved gastropods (especially in the lower part) and occasional thin sandstones (white orthoquartzites) and Cryptozoon layers (80 ft.) 4. thin-bedded ("flinty" ) dolomites (20 ft.). The thirty foot section exposed in the abandoned southeast part of the quarry (Fig. 12; Appendix) represents the transition between intervals 3 and 4 described above. Detailed examination reveals a remarkably varied sequence with numerous structures of sedimentological and paleoecological interest especially in light of the wealth of data now avail able on the environments and characteristics of recent shallow water carbonate sediments. Walker and LaPorte (1970, p. 931-933) provide a concise review of the literature and a summary of lithologic, paleontologic and primary structural criteria for recognition of subtidal to supratidal carbonate environments in ancient rocks. Reconstructions of paleoenvironments must of necessity follow and build upon an understanding of regional stratigraphic relations (for example, LaPorte, 1969, Walker and LaPorte, 1970, Thompson, 1970) but in the case of the Ogdensburg Dolomite (and the Theresa and Bucks Bridge Formations as well) such a stratigraphic synthesis is not available. Perhaps in the case of the Ogdensburg Dolomite attempts to analyze sedimentological and paleoecologic features of local sections will stimulate new attempts to work out the regional stratigraphy. The horizons are briefly described in the Appendix and some tentative correlations are made with Cushing's (1916) sections.
Interpretation
The combination of various features in the section suggests that the sediments accumulated in a protected (high intertidal) carbonate flat environment. Fluctuations in physical conditions are indicated by evidence of alternating flooding (influx of quartz sand, oolites, pellets, shell debris and lime mud) and subaerial exposure.
Laminated, mudcracked, carbonate muds -Thin bedded to laminated (ribbon-laminated), mudcracked, finely crystalline to aphanocrystalline carbonates characterize the tidal flat environment where lime muds are subjected to subaerial exposure; the irregular and regularly laminated horizons (e.g. 7-2, 7-5, 7-6, Fig. 9, 7-10) are believed to indicate sediment trapping by algal mats. Flooding of the tidal flat during storms or extreme tides would tend to break up the limy crust and resediment the clasts, forming intra-formational breccias (7-9, Fig. 10).
Fossils, oolites, pellets -The lenses of fossil debris, especially the small gastropods (7 8, 7-12, 7-13, 7-17, Fig. 15) and the oolites (7-11, 7-13) and pellets (7-3, 7-5) as well, represent material transported in from, more seaward environments (low intertidal to subtidal) during times of flooding. A wind-blown origin of some of the quartz is indicated by frosted grains haphazardly distributed in some beds. The paucity of fossils believed to be indigenous to the deposits and the general lack of evidence of infaunal reworking also suggest the ecologically adverse conditions of the high intertidal environment (Walker and LaPorte, 1970); Horizons 7-3, and 7-5, however, show evidence of bioturbation and vertical burrows occur in Horizons, 7-14 and 7-15 (Fig. 14).
Algal stromatolites -Algal stromatolites are perhaps the least equivocal evidence of intertidal and supratidal environments although they have also been reported from recent subtidal environments (Gebelein, 1969). Studies of present day algal stromatolites indicate that most active mat growth and sediment binding requires subaerial exposure whereas prolonged wetting inhibits mat growth (Logan and others, 1964). Tidal and splash water accumulating in depressions on the mat surface leads to differentiation of the laminae into discrete domes and inter-areas. Linkage of the lamellae in the inter-areas between domes is further inhibited by scour-and-fill. Changes in stromatolite morphology with growth reflect minor fluctuations in the physical environment (Logan and others, 1964). For example, the change from initial space-linked hemispheroids (Collenia structure) to digitate vertically stacked hemispheroids (Cryptozoon structure) seen in Horizon 7-12 (Figs. 11, 13) indicate a change in environment from protected intertidal to a somewhat higher energy, more exposed intertidal environment. Larger, well differentiated, club-shaped, stacked hemispheroids (Cryptozoon structure) are known from other levels within the Ogdensburg Dolomite (Fig. 16) and in present day stromatolite environments these occur on exposed intertidal headlands (Logan and others, 1964, p. 80) _
Stromatolite growth ceased at Horizon 7-12 when the laminae were flooded and blanketed with skeletal debris and other sediment carried in from offshore. The relatively fossiliferous levels in the upper part of Horizon 12 and Horizon 13 may indicate subtidal deposits, with Horizons 14 and 15 (Fig. 14) marking a withdrawal of the sea and the return of the intertidal conditions.
Early dolomitization -Penecontemporaneous or early diagenetic dolomitization of carbonate sediments is known to occur in tidal flat environments, particularly supratidal, in areas of high aridity (Illings and others, 1965; Shinn and others 1965). Magnesium-rich brines developing on or just beneath the surface in the supratidal and high intertidal environments percolate through and replace the original carbonate sediment. Dolomitization of the original sediment in the Ogdensburg Dolomite appears to have been complete; the minor amounts of calcite occurring at several levels is interpreted as late diagenetic void-fillings (7-17, Fig. 15). Early dolomitizatLon in the Ogdensburg Dolomite is suggested by the similarity of texture of the intraclasts in the breccias and the dolomitic crusts from which they were derived (7-9, Fig. 10).
Vugs -Calcite-and dolomite-filled vugs are particularly conspicuous in the finely crystalline and aphanocrystalline dolomite in the upper part of the section. Some of the smaller voids (7-13) resemble birdseye structures (Shinn, 1968) although many cavities are clearly the result of leaching of shell debris. Studies by Shinn (1968) of recent birdseye formation demonstrate that the more planar vugs result from dessication of exposed sediments and are thus indicative of the supratidal and also intertidal environments.
Section in Ogdensburg Dolomite. From the top:
Unit | Thickness | Description
7-17, 18 | 2' 6" | Dark gray and brown, finely crystalline dolomite with abundant small gastropods, weathering light tan. Other clasts include fine-grained, sandy dolomite, oolites and rare orthocone fragments. This horizon represents the uppermost faunal assemblage (zone 4, Hormotoma zone) described by Cushing (1916, p. 41, 48) from the upper Ogdensburg Dolomite (Fig. 15).
7-16 | 0' 4" | Light and dark brown, cross-laminated, coarse- and medium-grained, calcareous and dolomitic sandstone, weathering tan. Similar to gray sandstones of Theresa Formation seen at Stop 6.
7-15 | 1' 0" | Tan, irregularly laminated and ribbon-laminated, very finely crystalline (aphanocrystalline), sandy dolomite. Quartz grains scattered through matrix, form dark lamellae or infillings of mudcracks or burrows. The quartz is mostly coarse-grained (well rounded and spherical) but ranges down to fine-grained. The rock also displays minor cross-lamination and cut-and-fill structures, and slump bedding (Fig. 14).
7-14 | 3' 3" | Dark brown, thin-bedded and laminated, aphanocrystalline, sandy dolomite, weathering light tan. Discontinuous and wavy laminae of very fine-grained quartz and silt-sized quartz are occasionally truncated by burrow-like structures. Conspicuous large, calcite-filled vugs.
7-13 | 2' 4" | Dark gray and dark brownish-gray, finely and medium crystalline dolomite, weathering light gray. Mosaic of dolomite rhombs masks abundant oolite and shell fragments. Conspicuous lenses of shell-molds and irregular vugs (resembling birdseye structure), partially or totally filled with yellowish dolomite, on weathered surfaces.
7-12 | 1' 1" | Light gray-brown, medium crystalline dolomite forming substratum to horizon of algal stromatolites that rise 2 to 3 centimeters above the floor (Figs. 11, 13). The stromatolite layer is overlain by dark gray and brown, medium crystalline dolomite with oolites, gastropod fragments and clasts of fine -grained, sandy dolomite. Vugs filled with calcite crystals are conspicuous in lower and upper parts of the horizon.
| | Description of stromatolites: Initial space-linked hemispheroids, with close-linked hemispheroids as a microstructure in constituent laminae (Collenia structure), passing upward into discrete digitate, vertically stacked, hemispheroids with laminae of close-linked hemispheroids (Cryptozoon structure). Inter areas composed of finely and medium crystalline, sandy dolomite with patches and lenses of oolite, gastropod and orthocone fragments and clasts broken from the stromatolites. The quartz is scattered throughout and is medium-to coarse- grained and remarkably well-rounded and spherical (Figs. 11, 1 3). Believed to correlate with Bed 21 of Cushing's (1916, p. 41) Pythian Home section.
7-11 | 2' 0" | Dark gray, finely crystalline, sandy dolomite. Scattered quartz mostly coarse-grained with minor amounts fine- and medium-grained. Dolomite matrix in form of rhombs masking abundant and conspicuous relic oolites.
7-10 | 1' 11" | Dark brown and tan, thin-bedded to laminated, alternating finely crystalline dolomite (dark), and very fine -to fine-grained dolomitic sandstone (light). Sandy laminae are wavy and discontinuous.
7-9 | 0' 9" | Light gray, mudcracked, aphanocrystalline dolomite with lens of intraformational breccia at top. Breccia composed of rounded and angular intraclasts broken from dolomite and scattered in matrix of brown, finely crystalline, sandy dolomite. The quartz is mostly medium-grained, well-rounded, and spherical (Fig. 10).
7-8 | 2' 2" | Light gray to tan, medium crystalline, sandy dolomite with lenses of gastropod molds lined with dolomite crystals. Rock weathers light. Very fine-to coarse-grained quartz is mixed throughout the rock along with ovoid clasts of finely crystalline dolomite. Ghosts of gastropod shells are conspicuous in thin sections. This horizon appears to represent the Eccliomphalus (Eccliopterus) assemblage (zone 3) described by Cushing 1916.
7-7 | 2' 8" | Light gray, medium crystalline, sandy, calcareous dolomite, weathering light brownish-gray, with well rounded and spherical, medium-grained quartz (10%) and sparry calcite cement. Dark brown cores are conspicuous in the dolomite rhombs of the matrix and may be relic oolites.
7-6 | 2' 1" | Dark brown and gray, thin-bedded and laminated, finely crystalline dolomite with fine-grained, dolomitic sandstone filling mudcracks (Fig. 9 ).
7-5 | 1' 5" | Dark gray, irregularly laminated, finely crystalline and medium crystalline, sandy, dolomite weathering light brownish-gray. The quartz is fine-grained and angular to rounded. The dolomite rhombs have dark brown spherical cores which are believed to be relic pellets. Some slightly calcareous sandy laminae with calcite cement.
7-4 | 2' 10" | Light to medium gray, medium-grained, dolomitic sandstone, weathering light, with intraclasts of Horizon 7-3 in lower part. Quartz is mostly medium grained, rounded and spherical. Dolomite consists of very finely crystalline rhombs masking oolite and gastropod fragments.
7-3 | 0' 10" | Dark gray, irregularly bedded, mudcracked, finely crystalline, slightly calcareous, sandy dolomite with very fine-to fine-grained quartz. Dolomite matrix masks ghosts of fossil fragments, intraclasts of finely crystalline dolomite and pellets(?).
7-2 | 1' 5" | Dark brownish-gray to light gray, thin-bedded to ribbon-laminated, finely crystalline, sandy dolomite, alternating with very fine-grained, dolomitic sandstone.
7-1 | 1' 10" | White to light gray,coarse- to medium- grained, slightly calcareous, cross-laminated, orthoquartzite with dark gray clasts of sandy dolomite. Quartz grains well-rounded and spherical and cemented by silica over-growths. This distinctive white band, which can be traced in all the quarry walls, may correspond to Bed 9 of Cushing's (1916, p. 45) section the west side of Ogdensburg.
| | Base of section.

STOP 8. Allens Falls Fanglomerate or "basal breccia"
Located from index map, the pages were missing from the Guidebook pdf.

STOP 9. Type exposure of the Potsdam Sandstone at Hannawa Falls
Located from index map, the pages were missing from the Guidebook pdf.

STOP 10A. Bucks Bridge
Outcrops on east bank of Grasse River at confluence of Nettle Creek at Bucks Bridge; Chadwick's (1920) locality 55. Canton 15 minute quadranqle; Morley 7 1/2 minute quadrangle. Bucks Bridge Formation.
The strata consist of buff-weathering, thin-bedded to massive, gray, dolomite-cemented sandstone with rounded quartz grains. Many bedding surfaces show asymmetric ripple-marks, having a wave-length of 1.5-2 inches and an amplitude of 0.25-0.5 inch. Other bedding surfaces exhibit shrinkage cracks. There are many poorly preserved discoidal gastropods.
Berry and Theokritoff (1966, p. 876) inferred that deposition was "...in shallow, near-shore waters, possibly intertidal. The ripple marks and shrinkage cracks as well as the well-sorted, well rounded nature of the sand grains at this locality are considered indicative of possible intertidal conditions. Many types of snails are found today in intertidal areas... "

STOP 10B. Trout Brook
Outcrops in Trout Brook north of railroad bridge; Chadwick's (1920) locality 12. Canton 15 minute quadrangle; Hewittville 7 1/2 minute quadrangle. Bucks Bridge Formation.
Dendroid graptolites were recorded by Chadwick (1920, p. 33) from this locality in Trout Brook; Berry and Theokritoff (1966) erected a new species, Dictyonema potsdamense, to accommodate these dendroids. The graptolites are most abundant in a 2 1/2-3 inch-thick bed of medium-grained, dolomitic sandstone in the east bank of Trout Brook. Most are fragmented but a few have small discs, probably used for attachment to the substrate, at the apical end of the rhabdosome. A few discoidal gastropods, similar to those at Stop 10A, occur in the same bed as the graptolites, as well as in strata above and below.
The strata at this locality are similar lithologically to those in Nettle Creek (Stop 10A) but lack the ripple-marks and shrinkage cracks. However, they are laced with many tubular structures, ovoid to round in cross section, that are composed of compact, dolomite-cemented sand lacking all signs of bedding laminae. The tubes are unbranched, overlap one another at all angles forming an open mesh, and none crosses from one bed to the next. They disrupt bedding laminae that may be seen preserved between them. Although the tubes are moderately numerous in the graptolite-bearing bed, they are very abundant in underlying and overlying strata, comprising as much as 80 per cent of some beds.
Berry and Theokritoff (1966) inferred that the tubes were made by an organism that tunneled through the most recently deposited, relatively soft sediment; the weight of the most recently deposited sediment led to the expulsion of water from the underlying layers of sediment and so probably made these layers impenetrable to the organism. The abundance of the tubes suggests that the sediment originally contained a considerable amount of organic matter.
Berry and Theokritoff (1966) considered "that the graptolite-bearing strata were formed in relatively shallow water, albeit possibly more distant from shore than were the strata at Nettle Creek. The qraptolites themselves were inferred to have lived in small clusters or "gardens" attached to the sea floor; colony growth was possibly terminated when the sea-floor supporting the graptolite clusters was disrupted by organismal tunneling.

STOP 10C. Outcrops along railroad
Outcrops along railroad west of bridge over Trout Brook and east of Townline Road.- Chadwick's (1920) locality 11. Canton 15 minute quadrangle; Hewittville 7 1/2 minute quadrangle. Ogdensburg Dolomite.
The strata along the railroad here are light-gray-weathering, slightly sandy, gray calcareous dolomite. They contain algal stromatolites.
Berry and Theokritoff (1966, p. 873) assigned these strata to the Ogdensburg Dolomite and placed the lower contact with the Bucks Bridge Formation at approximately the elevation of the railroad track at the western bridge abutment. This contact dips northerly and crosses Trout Brook approximately 250 feet north of the graptolite locality.

C: SOME ASPECTS OF ENGINEERING GEOLOGY IN THE ST. LAWRENCE VALLEY AND NORTHWEST ADIRONDACK LOWLANDS
W.P Harrison & E.T. Misiaszek
Clarkson College of Technology
Potsdam, New York
ABSTRACT
The purpose of this field trip is to illustrate the interdependence of geology and civil engineering by means of several examples from the St. Lawrence Valley and the Lowlands of the Northwest Adirondacks. We will make seven stops in the vicinity of Norfolk, Massena, Potsdam, and South Colton, New York.
Stop 1 will be at a limestone quarry where the rock is processed for Portland cement and asphalt concrete aggregate. Here we will emphasize the interrelationship between the bedrock type and the physiography. Stops 5 and 7 will be at gravel quarries of very different geologic and physiographic character. The relationship of physiography and bedrock to gravel characteristics will be stressed. Stop 6 will be at concrete gravity dams on the Racquette River, for which much of the crushed stone and concrete aggregate was taken from the gravel pit at stop 5. We will indicate some of the desirable and undesirable properties of this fill for use in this particular dam project. At stop 2 we will visit the site of a landslide in the sensitive Leda Clay. Stops 3 and 4 will be in the Moses-Saunders Power Dam and Eisenhower Lock, respectively. Here the geologic parameters and problems of construction will be stressed.

STOP 1 -Barrett Allied Chemical Pit, Norwood, N.Y.
The ten to fifteen feet of glacial cover can be clearly seen at the southern end of the pit, and the fairly clean character of the overlying till is evident, as is the thin soil cover at the grass line near the top.
The rock is drilled, blasted, broken down further by the large steel ball, and trucked to the primary crusher, where it is sized, recrushed and stocked in piles according to size for use as Portland cement aggregates, asphalt concrete aggregates, and general engineering use as fills, drains, etc.
The rock which usually is hard and dense, probably extends 100 feet deeper than the present base of the pit.
Its denseness is apparent on the west side of the pit, where minimum pumping operation is required to keep out the water infiltrating from the river just over the hill, and whose elevation is considerably higher than the base of the pit.

STOP 2 -Landslide in Leda Clay
Landslide in Leda Clay on the Massena Springs Road Near the Massena Airport (Racquette Cemetery Site)
The general area of the Racquette cemetery site has been exposed to many earthquakes, the most severe that of September 5, 1944. Many smaller tremors have been recorded prior to and after this shock.
Structures founded on the marine (Leda) clay were most affected by earthquake shock, while those founded on glacial till showed much less response. The epicenter of the 1944 earthquake was located in Massena Springs, approximately one mile north of the cemetery site.
The last glacial ice sheet deposited many very dense glacial till moraines near the St. Lawrence River. Streams with their headwaters in the Adirondacks encountered these moraines, and generally cut through glacial outwash deposits and the clays, these offering the least resistance.
The cemetery site consists of marine clay deposited between two moraines. The moraines existed prior to the formation of Lake Iroquois, which deposited clay in the valley between the moraines. The highest points of these moraines are 250 feet and 230 feet above sea level for the south and north shore respectively.
Soil borings performed at the site on the north shore indicated a clay layer thickness of about 65 feet, where surface elevation was 200 feet. Since till was encountered below the clay, the valley between the moraines was at or below 140 feet. The clay offered very little resistance so that the water was confined between these two moraines.
The clay at the site is rather strong and somewhat pre-consolidated in the undisturbed state, but remolding causes a drop in shear strength to a very small value. If one looks closely at the surface topography immediately adjacent to the river as the bus proceeds along the road to this stop, old landslide scars will be evident in the form of small surface scarps.
The landslide located at this stop resulted from the combination of heavy loads on top of the slope (logs from cut elms, sand piles), and erosion of the clay by the river at the foot of the slope. Many graves were lost and the trees near the river were tilted. The small island nearest the cemetery is probably a remnant of an old slide.
Mr. Spencer Thew of Clarkson College has placed observation wells in the slide area, and has taken samples of the undisturbed clay. The failure plane of the slide can be seen in the field, and it is possible that the soil strength parameters existing before the slide occurred can be inferred from the data he will collect. Such studies of field failures may make it possible to prevent future slides and property damage and personal injury. Note how close the next group of houses to the right of the cemetery is to an apparent old slump scarp.

STOP 3 - Moses-Saunders Power Dam
The location map is shown in Fig. 4. This dam provides approximately 912,000 kilowatts of power. The dam has a head of 81 feet, and behind it is Lake St. Lawrence, with its fine marina and Barnhart Island Beach. A section through the Moses Power Dam is shown on Fig. 5, and of the Long Sault Control Dam on Fig. 6.
A thirty minute film will be shown in the auditorium at the dam, which will illustrate the methods and problems of construction.
A tour of the dam will be made, and from the top of the building Lake St. Lawrence can be clearly seen, with some of the zoned and rip-rapped dikes bounding it composed of compacted glacial till with dry densities on the order of 140 pcf (concrete is 150 pcf).

STOP 4 -Eisenhower Lock, St. Lawrence Seaway
This structure enables ships traveling the St. Lawrence River to pass around the Moses Saunders Power Dam and, along with Snell Lock five miles farther east, lowers the ships through a total of 95 feet of elevation. Both locks have dimensions of 860 feet by 80 feet and are of concrete construction. The locks are huge bathtubs in a sense, with openings along the sides into a passageway (about 13' wide by 15' high) on each side which slopes to the upstream end of the lock. When a ship comes down the St. Lawrence River and through the canal to the lock, the lower lock gates are closed, and the water is at the upper canal elevation. The ship moves slowly into the "bathtub", the upstream gates are closed, and then the water is let out of the locks through the openings in their sides, down the passageway on either side and discharged below the lock. A system of
baffles on the downstream end prevents excessive turbulence.
When a ship comes upstream to the lock, the upper gates are closed and the water level is at the same elevation as the water surface downstream from the lock. The ship moves into the lock, the lower gates are closed, and water is introduced into the side passageways from the upstream end of the locks flowing into the lock through the side openings, thus filling the lock and raising the ship to the elevation of the canal on the upstream side. Then the upper gates are opened and the ship moves out of the lock upstream. Recently, some deterioration of the lock concrete has been observed, and an extensive study has been made by the Corps of Engineers, which is resulting in appropriate remedial measures.
Since the overburden materials and lock location problems at Eisenhower and Snell Lock are very different, Figures 7 through 10 are included to show, for Eisenhower Lock, boring locations, exploratory core borings, some laboratory test data on overburden material and geologic sections. Figures 11, 12, 13a, 13b, 14 and 15 show the same data for Snell Lock. Note the difference in the overburden at the two sites 5 miles apart. Also note in Figure 11b boring 0-1302, which shows evidence of a possible fault at the site. This fault area is shown in Figure 12.

STOP 5 -The Martin Gravel Pit, "The Plains", South Colton
This pit is twenty miles from Potsdam on Route 56 towards Tupper Lake in the Adirondack Physiographic Province. The pit is part of a Kame Terrace deposit of very clean and uniform quality, largely composed of reddish brown gneiss. Excellent quality fine and coarse aggregate are produced from this pit. Due to its proximity to the construction site, most of the aggregate used in the construction of the five Niagara Mohawk dams on the Racquette River, completed in 1957, came from this pit.
At the site of the pit the company installed a large crushing, screening and washing plant for producing the aggregates for making concrete. This plant also produced several sizes of unwashed material for use in road and dike construction.
The processing plant was about 400 feet long and 100 feet wide covering about 2 acres. Stock piles of sand and various sizes of processed stone surrounded the plant, some of which were 100 feet in diameter, forty feet high, and contained as much as 8000 tons of product. The plant had a capacity of 200 tons per hour, and 15 men worked full time.
The operation starts with the "run of the bank" gravel and rocks which are fed into one end of the plant. As this material moves along the plant conveyor belts, the sand is separated and the rocks crushed, screened to size and washed. Waste material is screened out and the balance runs the gamut of vibrating screens, scrubbers and washers until there are a number of neat piles of various sized crushed stone and sand.
The crushed stone for the concrete was divided into 3 stockpiles, one with stone graded from 1/2" to 1"; one from 1" to 2"; and one with sand which varied from near a #200 sieve-size to 1/4".
Trucks took the various materials to the job sites where it was handled in batch plants as its first step towards becoming concrete for one of the project structures.
It is estimated that for the entire project about 400,000 tons of washed sand and gravel were used. This required excavating about 600,000 tons from the gravel pit and crushing about 300,000 tons of rock.

STOP 6 -The Niagara Mohawk Power Corporation Dams
The Niagara Mohawk Power Corporation Dams, South Colton to Carry Falls
The Racquette River Power Development Project added five new hydro-electric plants which boosted Niagara Mohawk Power Corporation's production capacity to almost 1 billion kilowatt hours of electricity per year. This is enough power to supply the needs of more than 400,000 homes. The project cost $33,000,000 and resulted in the creation of six new lakes and public areas for boating and fishing. Figures 16 and 17 show the plan and statistics of the project. (also Table 2).

STOP 7 -Bicknell Gravel Pit, West Parishville, New York
This site is also a Kame Terrace deposit, but the rock utilized for crushed gravel and sand shows different geologic characteristics from the Martin Pit of stop 5.
Cross bedding of sand, boulder pavements (concentrations of large cobbles in one area of the deposit), the effects of water-working and a wide variety of rock types can be seen here, allowing comparison to be made between different physiographic areas visited, the very different types of engineering material types and their relation to the area geology.
Sandstone, quartzite, gneiss, limestone can be observed at this pit, contrasting markedly with the uniform material at the Martin Gravel Pit.

D: ECONOMIC GEOLOGY OF INTERNATIONAL TALC AND BENSON IRON MINES
Willlam T. Elberty and Peter Lessing
St. Lawrence University
Canton, New York
Since 1964 International Talc Co. has mined commercial talc from its open pit at Fowler, New York. The minable product is tremolite-talc schist, a Grenville metasedimentary unit of the Balmat-Edwards district. Production of 80,000 tons annually accounts for 45 percent of New York State talc. The mineralogy of this complexly folded, Mg-rich unit is typical greenschist facies. The petrogenesis is complex and speculative, but replacement and/or isochemical metamorphism is suggested.
Iron ore, principally magnetite and hematite, are extracted by open pit methods at Benson Mines, New York. The 2.5 mile-long pit is located in the overturned eastern limb of a northerly-plunging syncline. Ore occurs disseminated in Grenville gneisses that average 23 percent iron. Average annual tonnage is 1.1 million, which yields a concentrate of 62 percent iron. A metasedimentary or replacement origin is postulated.

STOP 1. International Talc Open Pit
New York talc was originally discovered by Colonel Henry Palmer and in 1878 he opened the first commercial talc mine in New York at Talcville. Over the past 93 years talc has steadily grown in economic importance. Commercial talc from the Balmat-Edwards district is the only source in New York State and accounts for 22 percent of U.S. production or approximately 200,000 tons per year.
All of the producing and abandoned talc mines were underground operations until 1964 when International Talc started production from their open pit at Fowler. All mining operations in the district are confined to unit 13, a tremolite-talc schist that varies in thickness from 0 to 400 feet. It can be traced more or less continuously from Balmat to Edwards, some 10 miles.
Regional Geology
The Balmat-Edwards belt is a northeast-trending marble belt approximately 10 miles long and 1/2 to 2 miles wide. It is part of the Grenville metasedimentary sequence of northern New York. Within the marble belt ~6 lithologic units have been identified (Brown and Engel, 1956). These stratigraphic units can be traced with a fair degree of accuracy, the entire length of the belt. They are numbered 1 to 16 with number 1 presumably oldest (Table 1, Fig. 2). All units have been extensively folded and there is abundant evidence of cross-folding, flowage, and intricate contortions. The interested reader is referred to Brown and Engel (1956), Buddington and Leonard (1962), and Lea and Dill (1968) for complete descriptions and detailed maps. The area has been subjected to regional metamorphism of the upper amphibolite and lower granulite facies. This high grade metamorphism is characteristic of the silicate gneisses that surround the Balmat-Edwards marble belt. However, the marble itself exhibits a mineralogy typical of greenschist and lower amphibolite facies.
Mine Geology
Structure
The International Talc Co. open pit is located in the tremolite-talc schist of unit 13 of the Balmat-Edwards district (Fig. 2). Initial stripping of overburden was begun in 1962 and production started in 1964. Since that time the pit has been expanded to its present size of 1200 x 450 feet with a depth of approximately 60 feet.
Unit 13 strikes northeast and is overturned to the southeast. Dips generally vary from 45 to 50 degrees.The tremolite-talc schist persists to a proven depth of at least 1000 feet and probably greater. Alone strike to the south are remains of abandoned shafts to Wight, Woodcock and American mines and the producing Gouverneur Talc mine. There is evidence of fracturing, faulting, complex folding, and boudinage in many of the exposed surfaces. Minor and major folds plunge north at 15 to 50 degrees.
Mineralogy & Chemistry
Unit 13 is generally referred to as tremolite-talc schist, these being the major minerals present. All of the common minerals found in unit 13 are listed in Table 2. Mineral compositions of unit 13 are given in Table 3.
Table 1. Stratigraphic units of the Balmat-Edwards district (presumably oldest at bottom).
16 | Median gneiss
15 | Rusty marble
14 | Calcitic-dolomitic marble
13 | Tremolite-talc schist
12 | Dolomitic marble
11 | Dolomitic-diopside marble
10 | Anhydrite-gypsum marble (not exposed)
9 | Dolomitic marble
8 | Silicated dolomite
7 | Dolomitic marble
6 | Silicated dolomite
4 | Silicated dolomite
2 | Pyritic schist
Table 2. Common minerals of unit 13.
Diopside | CaMgSi2O6
Tremolite | Ca2Mg5Si8O22(OH)2
Anthophyllite | Mg7Si8O22(OH)2
Serpentine | Mg6Si4O10(OH)8
Talc | Mg3Si4O10(OH)2
Dolomite | CaMg(CO3)2
Calcite | CaCO3
Quartz | SiO2
Anhydrite | CaSO4
Biotite | K(MgFe)3(AlSi3)O10(OH)2
K-feldspar | KAlSi3O8
Phlogopite | K(Mg)3(AlSi3)O10(OH)2
Pyrite | FeS2
Table 3. Mineral composition of talc unit (volume %). (after Brown and Engel, 1956 )
| 1 | 2 | 3
Anthophyllite | 7 | 38.4 | 4.5
Dolomite | tr | tr | -
1. Average of talc unit, 5th level., Woodcock Mine.
2. Commercial talc, Woodcock Mine.
3. Average of talc unit, Balmat zinc mine.
Table 4. Chemical analyses of channel samples across 5 commercial talc zones in the Balmat-Edwards district, (after Engel, 1962).
* = Total loss on ignition (includes CO2)
** = Contamination ( ? )
The mineralogy represents typical hydrous assemblages of the greenschist facies. Distinction between tremolite, anthophyllite, and fibrous talc generally requires x-ray diffraction and/or optical examination. Most mineral percentages vary greatly throughout the schist. In general, however, the footwall (east) is tremolitic with tan serpentine (antigorite?), and the hanging wall (west) is enriched in fibrous and scaly talc.
Chemical analyses of 5 channel samples are given in Table 4. SiO2, CaO, MgO, and H2O total more than 98 percent.
Pleistocene
Of interest to "The Friends" are some extraordinary glacial features exposed in the pit. A conglomeratic "cement" no more than 0.25 inch thick is plastered over much of the polished and striated bedrock, even in places where the glaciated surface is vertical or overhanging.
On the northwest end of the pit the overburden is typically gravel, while at the southeast it consists of a thixotropic clay. This facies change is rather abrupt and needless to say presented difficulties during stripping operations. A more complete discussion of the Pleistocene at this locality can be found in the field Trip E guide.
Economic Geology
At the northern end of the pit are the remains of the old Arnold Mine. This underground operation had 15 levels, 45 to 65 feet apart, branching from a shaft that followed the dip for 850 feet (Engel, 1962). International Talc purchased the Arnold Mine property from Loomis Talc in 1956 and began production via open pit methods in 1964.
Mining methods are relatively simple. Talc ore is drilled, blasted, and truck-hauled to the jaw crusher, which is located just north of the pit. The Telesmith jaw crusher is 36 inches wide and 20 inches between adjustable jaws. At a 6 inch spread, the crusher has a maximum capacity of 500 tons per hour. Usual runs at the pit are approximately 100 tons per hour, or lower if smaller sizes are required.
The crushed ore is screened and separated usually at 4 inches with coarser material stored and the finer material hauled to the mill. The coarse-ground ore is trucked to the mill when supply warrants.
International's pit produces an average of 80,000 tons per year. This represents 45 percent of New York talc and 9 percent of U.S. production. The value varies depending on grade. Coarse commercial talc (80 percent less than 325 mesh or 44 microns) runs $30 per ton.
Top grade talc ore (average 1.4 microns) and fiber products sell at $90 per ton. Most of the products go to the paint and ceramic industries.
Petrogenesis
The origin of the tremolite-talc schist represents a complex problem as does that of the zinc deposits so intimately associated with the schist. There are no definitive answers, but certain facts place limits on interpretations.
1. The Balmat-Edwards district is predominantly dolomite and associated Mg-silicates.
2. The stratigraphy is reliable throughout the length of the belt.
3. Associated anhydrite, gypsum, and halite suggest an evaporite sequence.
4. Metamorphic foliation and primary layering are generally in good agreement.
5. Tremolite-talc ore was present prior to deformation.
6. Commercial talc is only found in unit 13.
Engel (1962) suggests that the talc unit is a product of the replacement of a siliceous dolomite. He notes that relict carbonate layers and lenses in the talc support this interpretation. If such a replacement occurred it was remarkably selective since tremolite and talc are almost exclusively restricted to unit 13. No other units of presumably similar composition contain commercial tremolite and calc.
Any hypothesis regarding petrogenesis must consider original composition and the stability of the present assemblage. Major variables that must be considered are T, P, PH2O, and PCO2. Geothermometry in the district (Engel, 1962; Lessing and Grout, 1971) indicates metamorphic temperatures of approximately 50°C. Pressures are more difficult to determine, but PCO2 was probably high as suggested by coexisting quartz and dolomite and lack of dissociated carbonate. Water is a minor phase suggesting low PH2O. The stability of anthophyllite at Balmat (Greenwood, 1963) also supports a low water pressure; perhaps only 2-3 bars. Load pressure is estimated at 2-4 kilobars.
The chemical composition of the schist is essentially a hydrous calcium-magnesium silicate. A replacement origin is certainly possible as Engel has suggested. However, the stratigraphic restriction of unit 13 may indicate a metasedimentary origin that was essentially isochemical. A possible parent material of siliceous dolomite with trapped connate water would provide the necessary chemistry. Metamorphism of this unit would require the loss of CO2 while retaining H2O. The separation of CO2 and H2O may be controlled by permeability and/or osmotic pressure.
Brown and Engel (1956) have pointed out a retrograde metamorphic sequence tremolite → anthophyllite → serpentine → talc. Elsewhere, Elberty and Lessing have noted the reaction diopside → serpentine and excellent examples of dedolomitization (Fig. 3) in which Mg has been removed from dolomite to make diopside, and leaving a selvage of calcite. This phenomenon is common in diopsidic dolomites. The characteristic greenschist assemblage is in large part due to retrograde metamorphism that did not noticeably affect the surrounding gneisses.

STOP 2. Benson Mines Iron Ore Deposit.
STOP 2. Benson Mines Iron Ore Deposit (Fig. 1). The Benson Mines magnetite-hematite deposit is located on the northwest slope of the Adirondacks in the Grenville province of the Canadian Shield. Knowledge of the deposit dates back to about 1810. Production of magnetite began around 1889 and the deposit was worked intermittantly until 1941 when it was leased by Jones and Laughlin Ore Company. In 1952, a merger formed the New York Ore Division of Jones and Laughlin Steel Company. At the present time, the plant facility has an annual production capacity of about 1,100,000 long tons of magnetite and 700,000 long tons of hematite concentrates. The deposit is 400 to 600 feet thick and about 2.5 miles long making it the largest known deposit of its kind.
Much of the following information was obtained from Leonard and Buddington (1964); Crump and Buetner (1968) and Palmer (1970). The reader is referred to these sources for more detailed discussion.
Regional Geology
Magnetite and hematite ores are confined to a relatively narrow horizon within a sequence of paragneisses which are infolded into granitic rocks of the Adirondack Highlands. Figure 4 shows the general geology of the area around Benson Mines. Palmer (1970, p. 31)recognizes four major units in the paragneiss sequence.
1. Mixed garnet-and pyroxene-feldspar gneiss.
2. Garnet-and sillimanite-quartz-feldspar gneiss (ore and mineralized horizon)
3. Migmatitic plagioclase gneiss.
4. Pyroxene-Quartz-feldspar gneiss.
The surrounding crystalline rocks consist of alaskite and hornblende granites and their gneissic equivalents.
Mine Geology
The paragneisses comprise a large, structural synform overturned to the west and plunging north about 20° in the vicinity of the mine. The paragneisses are subdivided into six lithologic units: 1) hanging-wall gneiss, 2) disseminated-garnet gneiss, 3) sillimanite gneiss, 4) ferromagnesian gneiss, 5) blotchy garnet gneiss, and 6) biotite gneiss. Important concentrations of ore are confined to units 2, 3, and 4, and some ore is found in unit 5. Thicknesses, mineral composition, and appearance of the units vary considerably. Sequence is an important aid to identification within the mine. Rocks similar to those exposed in the Benson Mine have been traced approximately 8 miles along the strike.
Hanging-wall gneiss. An extremely heterogeneous unit composed of a variety of different rock types including diopside, marble, quartzite, and hornblendite in bands 5 to 50 feet thick. Most of the unit consists of pink or gray hornblende and/or pyroxene gneiss. A pink, microcline pegmatite marks the immediate hanging wall throughout the deposit. Hornblendite and diopside rock are encountered in drill holes. Minerals include quartz, orthoclase, microcline, perthite, oligoclase, biotite, muscovite, hornblende, pyroxene, chlorite, with local garnet and sillimanite near the ore contact. Common accessory minerals are apatite, zircon, leucoxene, magnetite, and hematite.
Disseminated-garnet gneiss. Largely a potash feldspar-quartz gneiss with disseminated grains of garnet. Quartz with magnetite and disseminated garnet and biotite characterize the contact with the hanging-wall gneiss. Other minerals are pyroxene, hornblende, chlorite, muscovite, sillimanite, biotite and accessory apatite, zircon, pyrite and sphene. The ore is largely magnetic and the highest-grade ore in the southern half of the ore body was concentrated in this unit. The unit varies in thickness from zero to 350 feet.
Sillimanite gneiss. This unit is generally composed of orthoclase or microcline with low quartz and ferromagnesian content. Sillimanite is a common constituent of many sections, but there are thick sections exposed in the pit and in drill cores which do not contain sillimanite. The unit averages 350 feet thick with a maximum of 650 feet. It is absent locally in the northern end of the pit. Sillimanite gneiss contains most of the non-magnetic ore and the nature of the gneiss changes with the ratio of magnetic to non-magnetic ore. Biotite, chlorite, muscovite, and accessory apatite, zircon, sphene and leucoxene may be present.
Biotite-garnet gneiss. A light-gray, coarse-grained, orthoclase-quartz-biotite rock with knots or blotches of garnet. The rock is similar to the disseminated garnet gneiss and forms the footwall of the Benson Mines ore body. Pyrite, pyrrhotite, sillimanite, magnetite, apatite and zircon are present.
Ferromagnesian gneiss. This unit contains the high-grade magnetite ore of the northern part of the mine. It is lens-shaped with a strike length of about 3300 feet, an average width of 200 feet, and it pinches out in depth. The rock contains orthoclase and quartz with the quantity of hornblende, biotite, and pyroxene varying inversely to the quantity of magnetite. Other minerals present, 1n more or less abundance, are garnet, pyrite, pyrrhotite, sillimanite, and accessory zircon, spinel, and apatite.
Biotite gneiss. A medium-to fine-grained quartz-feldspar gneiss with biotite and local disseminations of garnet, sillimanite, chlorite, and hornblende.
There are no sharp boundaries between any of the above units. Units containing important concentrations of ore minerals may be traced for considerable lengths. Magnetic and non-magnetic ore are generally confined to specific lithologic units (Crump and Beutner, 196&, p. 66).
Assuming some potassium metasomatism as evidenced by the presence of K-feldspar pegmatites, Palmer (1970, p. 37-38) postulates "illiitic siltstones, calcareous silt or sandstone and carbonate lenses with either graywacke or soda shale" as original sediments.
In addition to the minerals mentioned 1n the description of the gneiss units, copper occurs rarely as native copper, chalcopyrite, chalcocite, bornite, covellite, azurite and malachite. Molybdenite occurs in pegmatite dikes and disseminated in some ore zones (Crump and Beutner, 1968, p. 61). Fluorite is present in some pegmatites.
A generalized plan and section of the major structure is given in Fig. 4 and a more detailed plan of the mine showing the distribution of the various units in Fig. 5. The ore body is located on the eastern limb of a synform, the Benson Syncline, which is overturned towards the west "and plunges 20° to N30°E. Smaller folds plunge 12° to S30°W and form an anticline and syncline in the overturned east limb of the Benson Syncline. They are of economic significance because they more than double the volume of ore-bearing rock. The Amoeba pit (Fig. 5) is interpreted as the bottom of one of the subsidiary synclinal rolls developed in the eastern limb of the Benson Syncline (Crump and Beutner, 1968, p. 53-54). It is the only place where the blotchy garnet gneiss (unit 5) has been found to contain sufficient iron mineralization to constitute ore.
Palmer (1970, p. 32) recognizes two stages of folding. Flow folding is shown by thickening and axial-plane schistosity in fold hinges, with accompanying mineral lineations. The latter were deformed by flexure-slip folding.
Ore is found where the stratigraphic footwall is overturned to form the structural hanging-wall. Ore stops at both the northern and southern ends of the pit where this hanging-wall relation ceases. Drilling, however, has penetrated 35 feet of ore-grade rock, resting on "hanging-wall" gneiss where there is no overturning (Crump and Beutner, 1968, p. sq).
Many of the relationships discussed above are illustrated in Fig. 6-10, with section lines given in Fig. 5.
Ore
Ore minerals are magnetite and hematite. The are is classified as magnetic if 80 percent or more of it is magnetite, and non-magnetic if magnetite comprises less than 80 per cent. Average grade is a function of economics. The distribution of the magnetic and non-magnetic ore is shown in Fig. 5 and a summary of their characteristics is given in Table 5. Table 6 gives representative analyses of the two kinds of ore and their respective concentrates.
Although the Benson Mines deposit is considered non-titaniferous, there is enough TiO2 present in the concentrate obtained from the Humphrey spirals to constitute a metallurgical problem.
Ore Genesis
Palmer (1970) discusses three possible origins for the magnetite-hematite ore in the Benson Mines deposit. 1) as a product of metamorphic differentiation. 2) as an epithermal replacement in the metasediments, and 3) as a metamorphosed iron-rich sediment. Each of these origins can explain the confinement of the ore to a restricted lithologic horizon; the fact that the ores have apparently been present during deformation and recrystallization of the host rock (Hagni, et al., 1968; Palmer, 1970); the presence of hematite and magnetite in different areas of the ore deposit; etc. Leonard and Buddington (1964), Buddington (1966), and Crump and Beutner (1968) favor a hydrothermal origin, because of the lithologic heterogeneity of the host rocks; the presence of skarn, a low-angle, cross-cutting relation between the ore and the host rocks; and the presence of veins of fluorite, calcite, quartz, and other minerals typically associated with hydrothermal activity. Palmer (1970) rejects both metamorphic differentiation and hydrothermal replacement in favor of a syngenetic, metasedimentary origin. Palmer feels that the confinement of the ore to a specific horizon within the paragneiss sequence, the relatively great lateral continuity of this horizon; the lack of any evidence of replacement of the host rock by magnetite or hematite, and the apparent presence of ore prior to deformation and metamorphism is best explained by metamorphism of iron-rich sediments.
Mining and Processing
Mining is carried out by open-pit methods. Magnetic and non-magnetic ores are differentiated by diamond drilling and are mined selectively. Operating faces are generally about 50 feet high. Blast-hole drilling is done with rotary drills. Ammonium nitrate explosives are used. Crude ore is loaded by 6-yard, electric shovels into 85-ton dump trucks for transport to the primary crusher. The plant is capable of handling 16,000 tons of ore per day.
Figure 11 illustrates by flow diagram the methods used to concentrate the magnetic and non-magnetic ores. Magnetic ore is concentrated by magnetic separators, with the final concentrate (minus 20 mesh) containing 63 to 65 percent iron. Non-magnetic ore is concentrated by gravity methods with auxiliary magnetic separation to collect magnetite, or by flotation to collect hematite and magnetite fines (minus 100 mesh). The concentrates are transported to the sintering plant where they are thoroughly mixed with fine anthracite coal, lime, and sinter fines in the ratio of 64 per cent concentrate: 5 per cent anthracite: 1 per cent lime : 30 per cent sinter fines. The sintering cycle takes about 11 minutes.
Sinter is shipped by rail to the Jones and Laughlin steel plants at Pittsburgh and Aliquippa, Pa. and Cleveland, Ohio.
Table 5. Summary of ore characteristics (after Crump and Beutner, 1968)
MAGNETIC | NON-MAGNETIC
1) Generally difficult to crush | Friable
2) Distribution generally confined to lithologic horizons | Same
3) Occurs in all lithologic horizons | Not found in ferromagnesian gneiss and only to minor extent in disseminated garnet gneiss
4) Generally high quartz gangue | Generally low quartz gangue
5) Sulfides present | Sulfides absent but with many limonite-filled vugs of a size corresponding to sulfides
6) Sphene present | No sphene but some leucoxene
7) Contains green or colorless, untwinned, potash feldspar | Contains pink or colorless, twinned and strained, potash feldspar
8) Rare labradorite grains in ferromagnesian gneiss ore | No plagioclase
9) Has fairly uniform gneissic structure and texture | Ptygmatic folding and pegmatitic lenses are quite common
10) Average grain size 1mm | Same
Table 6. Representative chemical analyses (after Crump and Beutner, 1968 and Palmer, 1970)
MAGNETITE
| Crude | Conc. | Crude | Conc. | A*
* Average of 8 whole rock analyses of ore (Palmer, 1970).

E: SOME PLEISTOCENE FEATURES OF ST. LAWRENCE COUNTY, NEW YORK
James S. Street
St. Lawrence University
Canton, New York
The field trip route from Potsdam to International Talc's open pit mine at Fowler crosses uneven ground moraine and a series of ice contact features. The latter have been mapped as part of the frontal Fort Covington Moraine. Kames, kettles, discontinuous eskers, and extensive sand plains are well displayed. Stop 1 will examine the core of one of these ice contact features, in Elm Creek Valley north of Edwards, New York.
Stop 2, at the International Talc open pit, will provide an opportunity to examine striae, gouges, and the remnants of highly polished flutes preserved on the bedrock surface. Patches of sand and gravel cemented to the rock surface form an unusual pavement. Drift exposures adjacent to the pit show Fort Covington sand, gravel and clay deposits. Stop 2 of this trip is same as Stop 1 of Trip D.
Pleistocene glacial events of a major part of St. Lawrence County have been interpreted by MacClintock and Stewart (1965). Their report on the St. Lawrence Lowland gives an excellent summary of previous investigations in the area and presents substantial evidence supporting the concept of two ice flow directions in the St. Lawrence Valley during the late Wisconsin Stage.
Using glacial striations and till fabrics as primary criteria for flow direction, MacClintock and Stewart identify an ice mass moving from northeast to southwest (Malone Glaciation) which, at maximum extent, spread over the Adirondack mountains. A later ice mass (Fort Covington Glaciation) radiating from a new source on the Ottawa Highlands moved from northwest to southeast. Malone drift, described as red-brown till and assorted ablation debris, is said to be leached usually 5 to 8 feet, whereas Fort Covington drift is grey-buff till and other debris that are leached only a foot or two. The southern boundary of Fort Covington drift extends diagonally across St. Lawrence County from Nicholville to Harrisville (Fig. 2). This uneven boundary forms many loops and re-entrants in a typically lobate pattern marked in places by strong frontal moraine topography (MacClintock and Stewart, 1965). Deglaciation accompanied by the draining of ice-dammed lakes in the lowland was followed by a westward incursion of marine water.

E: SOME PLEISTOCENE FEATURES OF ST. LAWRENCE COUNTY, NEW YORK

Broad, ridge-like hills of till
The field trip route along U.S. 11 between Potsdam and Canton traverses an uneven till-covered surface with several broad, ridge-like hills of till having long axes oriented approximately northeast-southwest. The hills are part of a broad belt of similarly-oriented topographic features which cover the northern portion of St. Lawrence County. Interpreted by MacClintock and Stewart as part of the recessional Fort Covington drift sheet, the hills are described as having formed perpendicular to the flow of Fort Covington ice. The hills have cores of Malone drift that have been "pushed into place" (1965, p. 7-B). Exposures into these features have not been found in the vicinity of the trip route.

Series of ice contact features
Southwest of Canton the trip follows N.Y. 87 to Hermon thence via Marshville and Stalbird toward Edwards along a series of ice contact features trending approximately north-south parallel to Elm Creek valley. Where internal structures are exposed, there are varying degrees of sorting and a chaotic arrangement of stratified drift. Precambrian rock types predominate but a variety of sedimentary rocks can be found in the gravel.
These deposits lie a long the Fort Covington frontal moraine and are composed of Fort covington Drift (MacClintock and Stewart, 1965, p. 102-105).

STOP 1. Ice contact debris south of Stalbird.
This stop provides an opportunity to examine the structure and composition of a "textbook" example of ice contact debris.

STOP 2. Open pit mine of International Talc Co.
Several glacial erosional features are preserved on the bedrock surface. Mineralogy and petrology of the mine are discussed in detail under trip D of this guidebook.
In several places the bare bedrock surface shows broad, highly polished grooves trending northeast-southwest (N 20°, azimuth). Prominent striations having a parallel orientation are well displayed in the grooves. A major set of fractures from 2-12" long can be seen across the rock surface. The fractures strike N 8° at the northeastern end of the pit but their orientation gradually swings more easterly (N 20°) toward the crest of a 15' bedrock rise. A second fracture zone west of the crest produces a series of small step-like features, some of which are slightly curved, having a strike of N 280° nearly perpendicular to both the more easterly set of features and the prominent striations. The orientation of these step-like features, and some of the associated fractures might stimulate discussion on the origin and directional properties of crescentic marks.
Patches of cemented sand and gravel adhere tightly to the bedrock in several places. Usually 1/4 inch thick, these patches are remnants of a pavement which covered the entire surface prior to the mining operation. Several flutes in the bedrock show the cemented material preserved in a vertical position.
Exposures of drift at the edges of the pit show approximately 5 feet of red-brown till overlain by oxidized sand and laminated silt and clay totaling some 30 feet. The stripping operation combined with slump of the walls prevents a clear understanding of drift relationships.

F: MINERAL COLLECTING IN ST. LAWRENCE COUNTY
George Robinson
Fort Jackson, New York
The purpose of this trip is to visit some of the classic mineral collecting sites of St. Lawrence County, observe their geology, and collect specimens. Stops will be made at: 1) the Bower Powers farm in Pierrepont, a world-famous locality for doubly-terminated tourmaline; 2) the West Pierrepont actinolite locality; 3) the gem diopside locality near DeKalb; and 4) the Gomer Jones farm in Richville, a well-known occurrence of dravite. Other minerals which may be found at these stops are apatite, biotite, calcite, chlorite, pyrite, quartz, schorl, tremolite and uralite.
The mineral collecting sites of St. Lawrence County may be classified as: 1) those of sedimentary origin; 2) those formed by fracture filling and 3) those of metamorphic and complex origin. These will be briefly discussed, as will their typical mineralogy and their collecting history.
General
The trip will consist of four stops which are located on the stop map, (Figure 1). Please note that nearly all the stops are on privately owned land. Please do not litter, and kindly abide by any restrictions or regulations set forth by the land owners regarding the use of their properties.

STOP 1. Bower Powers farm, Pierrepont, N. Y.
This locality is one of the world's most famous for doubly terminated black tourmaline crystals. The tourmaline appears to be of metamorphic origin, and occurs in contacts between Grenville Marble, and a quartz-tourmaline-biotite schist. Nearly perfect crystals are observed both within the quartz-tourmaline rock and separated from it, enclosed by marble. Often crystals are found loose in the soil where they have freed from the marble. It is interesting to note the absence of feldspar at this tourmaline deposit.
Mineralogy
1) Tourmaline | occurs as near perfect trigonal crystals with shortened c-axes and lacking the usual prismatic striations typical of the species. Riggs' analyses indicate this is an iron-magnesium tourmaline (Clarke, 1899). Crystals and crystal aggregates are commonly found associated with quartz and uralite. The common habit includes the following forms illustrated by Fig. 5 : trigonal prism (m), ditrigonal prism (a), rhombohedra (e) and (r), basal pedion (c), trigonal pyramids (o), and more rarely ditrigonal pyramids and second order hexagonal prisms (not shown).
2) Quartz | is typically milky and shows poor development, but occasionally clear to smoky crystals are found associated with the tourmaline. They are commonly prismatic, with hexagonal prisms and terminating rhombohedra being the only faces developed. The physical development of these crystals does not illustrate enantiomorphism.
3) Uralite | is an amphibole replacement of pyroxene. Actinolite commonly replaces diopside, and is a relatively common phenomenon in metamorphic rocks. However, complete, free-standing pseudomorphs are uncommon and the ones from this locality are well known for their perfection and sharp definition. They are usually associated with the tourmaline. Occasionally they grade into unaltered diopside or more rarely into rensselaerite.
4) Apatite | is uncommon, but sometimes is found in the calcite as small hexagonal prisms seldom over an inch long. The most common color is light green to brown.
5) Biotite | Pseudohexagonal sheets approaching four inches in diameter may be found. It is interesting to note that in areas where the mica abounds, tourmaline is not common.
6) Others | Chlorite, pyrrhotite, pyrite, calcite, scapolite, and diopside are also likely to be encountered here, but usually not as desirable specimens

STOP 2. Actinolite locality, near West Pierrepont, N.Y.
Most commonly observed as radiating fibers, or matted masses of acicular crystals, actinolite is seldom seen as large, perfectly developed euhedra. At this stop actinolite occurs in the latter mentioned form, and is found in a marble-calc-silicate rock. A few crystals of pyrite, quartz, and dravite have been found here, but are relatively uncommon. The most striking feature here is a fifteen foot outcrop of solid actinolite crystals. Each crystal is remarkably well formed and was probably formerly in contact with marble which has since eroded away.
Figure 5 illustrates the typical habit of the actinolite here. The following forms are usually well developed: orthopinacoid (a), prism (m), prism (e), clinopinacoid (b), and clinodome (r).

STOP 3. Gem Diopside locality, near DeKalb, N.Y.
This is the famous Calvin Mitchell farm to which all mineralogy texts refer when citing DeKalb, N.Y. as a noted locality for diopside. The crystals from here are without any doubt the world's finest gem diopsides. They occur in seams and pockets within the diopsidic host rock which is part of a long ridge composed chiefly of interbedded quartzite and silicated marble. The ridge trends northeast-southwest, and dips 45° to the northwest.
A typical diopside crystal is shown in Figure 7. The common forms include orthopinacoid (a), clinopinacoid (b), prism (m), pyramid (u), and basal pinacoid (c). The pyramids (u) are typically heavily etched, whereas all the other faces are smooth and glassy. Sometimes an asbestiform tremolite is observed growing into and parallel with the diopside, as if it were in the process of replacing it. A few complete tremolite pseudomorphs after diopside have been found here. Unlike other diopside in the Grenville rocks, this diopside seldom shows basal parting, and always exhibits good cleavage (11O).
Note: This locality is presently being mined for gem diopside, and mineral collecting is NOT permitted anywhere on the property.

STOP 4. Gomer Jones farm. Richville, N.Y.
Nearly all the famous large brown dravite crystals labelled as coming from Gouverneur, N.Y., probably came from this locality. Here coarse white tremolite crystals, as much as a foot in length, form a major part of the calc-silicate-marble bedrock. Associated with these large tremolites are white pyroxene crystals, apatite, and dravite. Mineralogy
1) Dravite | occurs as masses, grains, and complete crystals scattered locally throughout the deposit. The largest and best crystals are usually in intimate association with the tremolite and coarsely crystalline calcite. Occasional small, free growing crystals are found in the marble, and loose in the soil. The habit is similar to the Pierrepont tourmalines, with the exception of a few longer, more prismatic crystals.
2) Pyroxene | occurs as small, white to light tan colored crystals in veins in the hard calc-silicate rock. They are presumably diopside, but lack the familiar green color.
3) Apatite | has been found enclosed in the coarse calcite in the floor of the pit at the east end of the hill. The crystals are sharp hexagonal prisms of blue color, and are not commonly encountered.

THE NEW YORK STATE GEOLOGICAL ASSOCIATION
CO-HOSTED by COLGATE UNIVERSITY and UTICA COLLEGE
SEPTEMBER 15, 16, 17, 1972. HAMILTON and UTICA, NEW YORK
FIELD TRIP GUIDEBOOK
James McLelland, Editor
Department of Geology, Colgate University, Hamilton, New York
Department of Geology, Utica College, Utica, New York
Published by the New York State Geological Association.
Additional copies available from the permanent secretary,
Philip C. Hewitt, Chairman, Department of Geology and Earth Science, State University College at Brockport,
Brockport, New York 14420. DEDICATION
The Guidebook for the 44th Annual Meeting of The New York State Geological Association is dedicated to G. Arthur Cooper
Colgate Alumnus
Eminent Contributor to North American Paleontology
PREFACE
This year's guidebook reflects the preponderance of sedimentary and glacial geology in the Utica-Hamilton area. It is a geologically classical region, first made famous by James Hall. It is also the area in which G. Arthur Cooper began his paleontological studies while an undergraduate at Colgate University. It is with great pride that we dedicate this year's guidebook to Dr. Cooper.
In the past the New York State Geological Association Meeting has been convened in the spring. This year we are holding it in the fall for several reasons. Amongst these is the rededication of Lathrop Hall at Colgate University. Lathrop Hall has long been the combined home of both the Geology and the Physics Department. In 1970-1971 the old edifice (1909) was renovated, and a new link was added between McGregory and Lathrop Halls. The current facility is both spacious, attractive and functional.
We are honored to have as guest speakers and panelists for the rededication G. Arthur Cooper, M. King Hubbert, and J. Tuzo Wilson. They will be joined by two Colgate physics alumni: Guyford Stever, Director of the National Science Foundation; and Harvey Picker, Dean of the School of International Relations of Columbia University. We welcome these men, and we welcome all of you to the rededication ceremonies and to the other functions of this weekend.
-James McLelland, Editor

A: EAST-WEST FACIES CHANGES IN THE CLINTON GROUP (MIDDLE SILURIAN) OF EAST-CENTRAL NEW YORK
H. S. Muskatt
Utica College
The only completely conformable, exposed sequence of the Clinton Group (Middle Silurian) of New York State is located in its type area in the east-central part of the state. The Group is characterized by a heterogeneous lithology that includes pebbly sandstones, impure and clean sandstones, shaly, green and gray mudstones, carbonates and ironstones. Except for the Medina Group of upper Lower Silurian age, the Clinton Group, at its type locality, contains the only major sequence of detrital clastics in the Silurian of central and western New York.

NYSGA 1972 Trip A

Petrified Creatures on right.

Route to South would take you to Cooperstown, etc.
Right turn (S) off Rte.20 goes to Glimmer Glass State Park located on the northern end of Otsego Lake. Cooperstown and the Baseball Hall of Fame is located on the southern end of the lake.

View of Mohawk Valley and Adirondacks
Nice view of Mohawk Valley in middle distance and Adirondacks in far distance.

STOP 1. (30 min.) Wagner Hill Rd., Sta 33
Otsquago Formation (Picture Stop)
Nine feet of cross-bedded, ripple marked Otsquago red beds are exposed on the east side of the road. Another 35 feet of the unit is exposed in the woods across the road, northwest of the stop.
The outcrop is small but spectacular. Please stand back to allow others to take photographs first. This is a picture stop.

Outcrops of Otsquago sandstone on left (W) side of road, Station 29.

STOP 2. (45 min.) Otsquago Formation, Sta. 28
Forty-two feet of the Otsquago is exposed. The first 15 feet, on the east side of the road, shows medium-to coarse-grained, cross-bedded red sandstones with some interbeds of green and gray shales which may be part of the Sauquoit. The remainder of the section is found on the west side of the road. Tracks and trails are common in this exposure, particularly Cruziana.

STOP 3. Otsquago Formation, sta. 27
Fifteen feet of cross-bedded, pebbly, coarse-grained sandstones art exposed. Three cross-bedded units are present. Lenses of conglomerate and some phosphate pebbles are also seen. Graded beds, fining upward, is evident.

STOP 4 Aney Hill Rd at intersection with Tri-Town Rd., station 22
Willowvale Shale, Kirkland Iron Ore, and Jordanville Member of Herkimer Formation.
This outcrop was recently exposed by a new road cut and has not been previously reported. It is one of the very few readily accessible exposures where contact of the Kirkland with the underlying Willowvale and overlying Jordanville may be seen. The contacts are located at the northern end of the exposure, downhill. A little digging and weeding may be required.
The Kirkland is approximately 11 inches thick and is fossiliferous. Palaeocyclus is common. (PLEASE DO NOT STRIP THE EXPOSURE. ABUNDANT SAMPLES OF THE KIRKLAND MAY BE TAKEN AT THE LAST STOP). Digging exposed about 2 feet of Willowvale below the Kirkland.
About 40 feet of Jordanville is exposed above the Kirkland; the uppermost 5 feet is in the field to the east. The lower 8 feet of the Jordanville is a "transition" zone showing alternating beds of reddish, blackish, and greenish sandstones with some thin grayish shale interbeds. Above this zone is the "typical" white orthoquartzite of the member. A 2 inch thick layer of gray shale is seen about 8 feet above the "transition" zone. No fossils were seen in the shale. Cross bedding, channeling, ripple marks, shale pebbles, and lenses of pebbly sandstone and conglomerate are present. A few trails were found. Glacial striae and chatter marks on the Jordanville in the field strike N85W.
LUNCH (45 min.) Mr. Aney has kindly offered the use of his front lawn for our use. PLEASE KEEP IT CLEAN.

Frankfort Shale (Middle Ordovician) exposed on both sides of road.

Frankfort Gorge, rte. 171, Exposure of Frankfort Shale (Middle
Ordovician) along the route.

STOP 5 (1 hr.) Rte. 171, Frankfort Gorge, Moyer Creek, station 11
CAUTION This road is fairly well traveled and is one of several in the area considered as the racers delight.
Frankfort Shale, Oneida Conglomerate, Otsquago Sandstone
Exposures are seen on both sides of the road. The Oneida disconformably overlies the Frankfort Formation (upper Middle Ordovician). A minor amount of channeling may be seen at the contact.
Pebbles of Frankfort Shale are incorporated in the lower part of the Oneida. The basal 5 feet of the Oneida is conglomeratic with the lowermost few inches containing abundant pyrite. The remaining 22 feet of Oneida is mostly medium-to coarse-grained white sandstones with some interbeds of pebbly sandstone and conglomerate. On the south side of the road some thin greenish shale lenses and clay galls to 4 inches are present.
Twenty-seven feet above the Oneida-Frankfort contact the Oneida grades into the reddish to blackish Otsquago. Cross bedding is very common. A few unidentifiable brachiopods are present in some beds.
The well known South Moyer Creek section (Grossman, 1953) starts about 300 yards south of the junction of that tributary with Moyer Creek about 100 yards west of the bridge over Moyer Creek.

Heading down east wall of Sauquoit Valley, a glacial trough.

Climbing west wall of Sauquoit Valley
Climbing west wall of Sauquoit Valley, look behind to east for a view of the glacial trough.

Last operating iron mine in central NY
Building foundation at left is that of the last operating iron mine in the central New York area which closed in the early 1960's

STOP 6 (3 hrs.) New Rd, Dawes Creek, station 3
Sauquoit Formation, Westmoreland Iron Ore, Willowvale Shale, Dawes Dolostone, Kirkland Iron Ore, Joslin Hill Member of the Herkimer Formation.
This section starts below the bridge on New Rd. that crosses Sherman Brook but locally referred to as Dawes Creek.
WE WILL REBOARD BUSES UPSTREAM WHERE IT CROSSES DAWES AVE.
Going upstream, 46 feet of the Sauquoit is exposed. The unit consists of greenish shales with discontinuous interbeds of calcareous sandstones and very-fine grained sandstones. Some of the interbeds show cross lamination on a fresh surface.
About 15 feet above the last exposure of Sauquoit turn left (N) up a normally dry tributary valley. At the foot of the tributary 3 feet 3 inches of the oolitic Westmoreland Iron Ore is exposed. (Abundant ore for samples may be taken at the top of the tributary.) Above the Westmoreland 23 feet of the Willowvale Shale is exposed. The lower part of the Willowvale is predominantly greenish shale with a few beds of calcareous siltstone and sandstone. The upper part is mainly grayish silty shale with some interbeds of calcareous siltstone, sandstone and sandy dolostone. Between the upper and lower parts of the unit is a 4 foot transition zone which starts approximately 10 feet from the base of the unit. Fossils are present.
At the top of the tributary turn left (W) about 25 feet.
Dawes Dolostone
Contact of the Dawes with the underlying Willowvale is not seen here. Across the valley the contact is visible and the Dawes, there, as well as upstream, is cross-bedded. Here 7 feet 8 inches of the Dawes is exposed. The unit consists predominantly of sandy dolomitic limestone and dolostone with some interbeds of shale, siltstone, and calcareous sandstone. Some fossils are present.
The Dawes grades into the overlying fossiliferous Kirkland Iron Ore. Only 3 feet 2 inches of the ironstone is exposed here. Further upstream the Kirkland (5 feet thick) is seen to grade from the Dawes and into the overlying Joslin Hill.
Turn around and follow the path east along the valley top to Dawes Picnic Grove. Go past the buildings and follow the road to the parking lot. The floor of the parking area is on the Joslin Hill. Abundant Rusophycus is scattered about. North of the parking area is an abandoned quarry. The Joslin Hill is composed chiefly of gray intercalated shale, siltstone, dolomitic sandstones, and sandy dolostone. Ripple marks and fossils are present.
(IF TIME PERMITS RETURN TO PICNIC TABLES FOR OPEN DISCUSSION)
Continue upstream along the Joslin Hill. A total of 36 feet of Joslin Hill is exposed along the stream. Ripple marks are fairly common and mud cracks rare. Go directly upstream until you reach the first waterfall east of the bridge that is on Dawes Ave. Several ripple marked beds are present as you continue upstream. The wave length of some reach 44 inches.
Bridge on Dawes. Ripple mark sets beneath bridge and continuing upstream. Wave lengths to 44 inches.

B: SEDIMENTOLOGY AND STRATIGRAPHY OF THE SALINA GROUP (UPPER SILURIAN) IN EAST-CENTRAL NEW YORK
Michael Treesh
Rensselaer Polytechnic Institute
Abstract
The available evidence from outcrops suggests that the Salina Group of east-central New York was deposited in peritidal environments of a transgressing epeiric sea. Sedimentologic criteria suggest that the depositional environments were hyper-saline with evaporites including halite deposited. The lithofacies of the Salina Group and the restricted fauna are characteristic of hyper saline conditions. The units underlying and overlying the Salina Group are "normal" marine carbonates.
Evidence from outcrops and subsurface studies indicates that the evaporites were deposited in environments which may have ranged from shallow water to supratidal. Thick accumulations of Salina Group rocks resulted from structural activity within the depositional area rather than from infilling of a deep topographic basin.

NYSGA 1972 Trip B

STOP 1. Vernon Shale
Start at Junction N.Y. 51 & Jerusalem Hill Road. The exposures on the south side of Jerusalem Hill along the creek are near the bottom of the Vernon Formation. The Vernon here is a massive red shale. A few green spots can be seen in the red shale. These apparently result from reduction around particles of organic matter; dark carbonaceous debris occasionally can be found in the center of these green spots. Green color is also present along joints indicating color change due to ground water action.
The contact of the Vernon with the underlying Lockport Formation is exposed along the west side of Steele Creek about 1000 feet north of this exposure. The Lockport is a medium-bedded dolomite with mudcracks and current ripples. The contact of the Lockport with the Vernon is sharp but may be conformable. The thickness of the Vernon in Ilion gorge is 120 to 160 feet.

STOP 2. Syracuse Formation
Pull off just west of Bridge where creek crosses road. Outcrop is 0.1 miles further west.
This stop exposes a nearly complete section of the Syracuse Formation. The lower contact of the Syracuse with the Vernon is not exposed. The contact with the overlying Camillus is gradational. The section is as follows:
Camillus Fm.
Syracuse Fm. (94 ft.)
| Upper Dolomite Mbr. (14 ft.)
| Upper Clay Mbr. (7 1/2 ft.)
| Middle Dolomite Mbr. (7 1/2 ft.)
| Lower Clay Mbr. (11 ft.)
| Transition Mbr. (54 ft.)
Ripple marks and mudcracks can be found throughout the Syracuse and Camillus Formations at this locality. Ostracodes and other fossils are present in the Middle and Upper Dolomite Members, and algal heads in the Upper Dolomite Member. Note also the finely laminated nature of the dolomites and dolomitic sediments; these laminations are characteristic of peritidal deposits.

STOP 3. Camillus Formation Quarry on left (S) side of road.
The section to be examined is in the quarry on the south side of Jerusalem Hill Road. About 80 feet of Camillus are exposed in this quarry. The total Camillus thickness in this area is about 180 feet. The section in this quarry is typical of the middle and upper Camillus. The lower portion of the Camillus, however, is more dolomitic. With the exception of a few mud-cracks, sedimentary structures and fossils are generally absent.

STOP 4. Bertie Formation
Junction of Jerusalem Hill Road and Cedarville Road, Town of Litchfield Maintenance Building on left (S) side of road. Outcrop is across Cedarville road from building.
This is a brief stop to examine the Fiddlers Green and Forge Hollow Members of the Bertie Formation. These units will be examined in more detail at the next stop. Mudcracks and eurypterids are common in the massive bed at the top of the Fiddlers Green. Poor outcrops in the field above the roadcut may be in the Cobleskill Formation. About 13 feet of the Fiddlers Green Member and 25 feet of the Forge Hollow Member are exposed here. The composite thickness of the Salina Group along the Jerusalem Hill Road in Ilion gorge is about 450 feet.

STOP 5. Camillus and Bertie Formations
Outcrop on left (E) side of road in passage gulf.
The section in this roadcut is as follows:
Bertie Fm. (40 ft.)
| Forge Hollow Mbr. (23 ft.)
| Fiddlers Green Mbr. (17 ft.)
Camillus Fm. (25 ft.)
The Camillus-Bertie contact can be examined at this stop. This contact is quite sharp. Below the contact, the Camillus consists of gray and green dolomitic shales with mudcracks. The overlying Fiddlers Green Mbr. of the Bertie Formation is medium- to thick-bedded dolomite. Mudcracks are present throughout, especially in the two foot massive bed at the top of the Fiddlers Green Member; this bed also contains eurypterids. The Forge Hollow Member is a shaly dolomite with some mudcracks and is exposed in the gentle slope just above the massive bed.

STOP 6. Syracuse and Camillus Formations
Road cut on east side of road. Another exposure about 0.1 mile south on west side.
The Salina Group in this area has thinned to less than 150 feet from the 450 feet measured in Ilion gorge. The Vernon Formation is not present as the result of depositional onlap. The easternmost exposure of Vernon shale is about eight miles to the west, north of Jordanville.
About 45 feet of Clinton sandstones, shales, and hematite beds are exposed below the Syracuse Formation. The contact with the Syracuse is at the top of a poorly consolidated conglomeratic sandstone (Herkimer). This contact is disconformable.
The Syracuse at Van Hornesville is about 80 feet thick. Although member designations are difficult, the lower 55 feet appears to consist of the transition and Lower Clay Members. The Middle Dolomite Member is about 10 feet thick; the Upper Clay Member, eight feet; and the Upper Dolomite Member, 15 feet. Mudcracks are present throughout the Syracuse Formation. Halite crystal casts associated with mudcracks have been found on some talus slabs. Algal heads and burrow trails are present in the Upper Dolomite Member. Some lenses of fine-grained non-laminated dolomite are present in the well-laminated Upper Dolomite Member. Eurypterid fragments are also found in this member.
The Syracuse Formation grades upward into the Camillus Formation. The Camillus is a grayish-green to dull red dolomitic shale. In places, fragments of the grayish-green sediment can be found contained in a red matrix. This is the easternmost exposure of the Camillus Formation; the correlative interval to the east is designated Brayman Shale.

STOP 7. Syracuse and Brayman Formations
Quarry set off road (on east side) about 100 feet.
The Syracuse Formation has thinned to less than 30 feet at this quarry from nearly 100 feet in Ilion gorge 25 miles to the west. In addition to thinning eastward through overlap, the sedimentology of the Syracuse Formation at Stop VII is quite different from Ilion gorge (Stop II). The Syracuse consists of thin-bedded laminated shaly dolomites with very abundant nodules throughout. The nodules are now filled with calcite which probably is secondary after gypsum or anhydrite. Around these nodules the dolomite has been brecciated. In addition to the nodular fabric, mudcracks are quite abundant in the Syracuse Formation. Some ripple marks, cross laminations, and fossils (ostracodes, gastropods, and brachiopods) are also present. The exposure is probably quite near the eastern depositional limit of the Syracuse Formation and more frequent subaerial exposure should be expected. The abundance and types of sedimentary structures and the nodular fabric suggest a supratidal or near supratidal environment of deposition.
The overlying Brayman Formation is a massive greenish gray shaly dolomite and dolomitic shale. Well-rounded sand grains can be found in this unit; these sand grains may be eolian. A 12 inch dolomite bed near the top of the quarry may represent the influence of Fiddlers Green sedimentation even though the Bertie Formation is not recognizable this far east. The thickness of the exposed Brayman at this locality is about 20 feet.

C: STRATIGRAPHY OF THE MARINE LIMESTONES AND SHALES OF THE ORDOVICIAN TRENTON GROUP IN CENTRAL NEW YORK
Barry Cameron
Boston University
For about 150 years the Ordovician rocks of the Mohawk Valley region have been under study. Many geologists and paleontologists of the 19th and 20th centuries have studied the limestones, shales, and fossils of the Black River Group and the Trenton Group in the Black River, West Canada Creek, and Mohawk River valleys (see Kay, 1937, for an historical review of early work). As a result, these rocks have become well-known as part of the medial (middle time of a three-fold subdivision) Ordovician standard section of North America.
However, the geology of the Trenton Group, as well as the Black River Group, still poses several relatively complex and interesting stratigraphic problems. Exposures are occasionally complete, but many are not. The repetitious nature of the sedimentary layers of the Trenton Group often mask significant variations critical to correct lithostratigraphic, biostratigraphic, and paleo-ecologic interpretations. The modern approaches to the study of paleoenvironments of carbonate rocks have just recently been applied with emphasis to parts of the medial Ordovician sequence in central and northwestern New York. Many previous investigators who have studied these formations have been, by necessity, primarily concerned with lithostratigraphy, such as statistical analysis of rock types (especially Chenoweth, 1952, and Lippitt, 1959), biostratigraphy and correlation, and mapping. Present and future work depends and will depend heavily on that of earlier workers who prepared the way by determining the basic lithostratigraphic and biostratigraphic frameworks which will be examined and evaluated on this field trip. The interests of this author center around establishing a detailed time and lithic microstratigraphic framework for the Trenton Group in central and northwestern New York. This would form the basis and provide the confidence for reconstructing the environments of deposition and determining the paleogeography. At present, special emphasis is being placed on statistical analysis of the rock types from both detailed field measurements and carbonate petrography, small scale physical and biological correlation, primary sedimentary structures, trace fossils, fossilization, and fossil community analysis. This information should better document the initial and subsequent wider transgressions and regressions of the Trentonian sea.
The purposes of this field trip to the Trenton Group limestones of central New York are to: 1) Demonstrate the stratigraphic succession and lateral facies changes. 2) Discuss and evaluate the age relationships and time correlations. 3) Examine and evaluate the criteria for determining the conditions and environments of deposition and paleogeography.
This field trip guide will summarize previous work on the Trenton Group in central and northwestern New York. The order of localities has been chosen to be as conveniently as possible for economy of travel along a southeast to northwest traverse that also essentially climbs up the stratigraphic succession.

NYSGA 1972 (Trip C)

STOP 1. Canajoharie Creek
Walk straight ahead on road, keeping to right of green house, until you reach the first wooden posts on the right that are blocking a macadam path. Take this macadam path do,m to the west bank of Canajoharie Creek. The Sugar liver Limestone is exposed along the path. At the end of the path, walk about 100 feet onto the flat area to get a better look at the exposure.
Three formations will be seen along Canajoharie Creek at the southern edge of the village of Canajoharie: Chuctanunda Creek Dolostone, Sugar River Limestone, and Canajoharie Shale. The Chuctanunda Creek is a stromatolite-bearing, otherwise unfossiliferous, early Ordovician (Canadian) dolostone disconformably underlying 17 feet of Sugar River Limestone. The latter is succeeded conformably by the Canajoharie graptolite-bearing black shales. At this locality the Sugar River probably represents more shallower water conditions than the relatively deeper water, more-burrow reworked, Sugar River lithologies to the northwest. The base contains atypical shelly calcarenite and a pararippled bed, followed by a concentration of calcisiltites. The middle contains more typical burrow-reworked non-Shelly calcarenite. Near the top, along the macadam path, several thick, shelly calcarenitic lenses occur that probably represent channels.

STOP 2. Route 55 South of Little Falls
Walk to quarry 100 feet to the right (north) side of road. Then return to highway and examine exposures along south side of Route 5S.
Along the west-facing hillside, a quarry and roadside exposures may be found. The quarry contains about 2.5 feet of Gull River Limestone (middle Black River Group) succeeded by about 18 feet of very fossiliferous Kings Falls Limestone. The latter contains shelly and non-shelly calcarenites with current laminations alternating with thin shales and burrow-reworked horizons. Along the roadside, there are 15 feet of Sugar River non-shelly, somewhat burrowed calcarenites with horizontal and cross-laminations visible. This is succeeded by about 10 feet of Dolgeville Facies which is composed of 6 feet of alternating thick black shales and black, argillaceous calcisiltites followed by about 4 feet of shale.

STOP 3. City Brook (locality #C1):
Walk across bridge and down steps on upstream side of bridge leading to stream bed. Then, climb back to bridge and walk up the opposite bank of City Brook. Obey no tresspassing signs farther upstream.
The Gull River Limestone of the Black River Group lies disconformably on the quartz arenite-rich late Cambrian Little Falls Dolomite below the bridge. The lower falls is supported by the upper Gull River Limestone, and the upper falls (Craig, 1941, fig. 5; Kay, 1953, fig. 11) is supported by the middle Kings Falls Limestone. The Rathbun member at the top of the Sugar River Limestone and the superjacent Denley Limestone will not be examined because we will have to respect the NO TRESPASSING signs.
Gull River Limestone. The lower 8 feet are tan weathering, gray, quartz-arenite-rich, ostracod-bearing, impure, thick-bedded, medium-textured, argillaceous limestones interbedded with a few calcareous shales up to 3 inches thick. Vertical burrows are abundant. A 3-inch thick metabentonite occurs at 6' 9" (Kay, 1943, 1953).
The upper 19.5 feet of the Gull River is composed of relatively pure, light gray weathering, dove gray, conchoidally fracturing calcilutite (sublithographic) and some calcisiltites. Stylolites are abundant from 11 to 16 feet. Thin shales are frequent between 13 and 16 feet, at the 13th foot, and especially between 19.5 and 21.5 feet where the limestones are very argillaceous (Fig. 3). Vertical burrows (Phytopsis) are abundant between 11 and 16 feet and in the top foot. Mudcracks occur above and below the 25th foot. An intertidal to lagoonal origin is probable for these limestones.
Kings Falls Limestone. Sediment from a coquinal calcarenite bed at the base of the Kings Falls fills some of the burrows in the highly burrow-reworked calcilutite bed at the top of the Gull River. The Kings Falls is characterized by coquinal calcarenites, as at the previous locality, in contrast with the non-coquinal calcarenites of the superjacent Sugar River Limestone. Cross-laminated and pararippled beds are frequent.
At 7 feet a deep reentrant marks where a metabentonite is weathering out. Less than a mile north, at Buttermilk Creek, this clay is 9 feet above the base of the Kings Falls (Kay, 1953). If this altered volcanic ash near the base of the Kings Falls between Stony Creek and Buttermilk Creek is part of a single bed, then it represents a synchronous time surface indicating that this formation is onlapping the Gull River eastward. Therefore, the base of the Kings Falls becomes progressively younger eastward, increasing the gap in time marked by the black River-Trenton boundary in that direction.
Sugar River Limestone. The contact between the Kings Falls and Sugar River limestones is drawn where shale becomes more abundant. This coincides with a contact drawn where non-coquinal calcarenites become persistently abundant and coquinal calcarenites almost disappear. The Sugar River at this exposure is mainly composed of interbedded coarse-grained calcarenites and calcareous shales. These calcarenites are encrinitic and rich in bryozoa, especially cryptostomes. The shales are especially abundant in the lower 10 feet, thus further accentuating lithic contrast with the upper Kings Falls below. The Sugar River Limestone contains the Cryptolithus tesselatus Zone which is characterized by C. tesselatus and the relative abundance of Prasopora. Unusually large Prasopora occur near the top.

STOP 4. Rathbun Brook
Walk to right, down farm road and be careful as you go through barbed wire fence.
The upper Sugar River and lower Denley limestone will be seen on Rathbun Brook. The 2.5 feet of very fossiliferous, burrow-reworked, argillaceous, black, hard Trocholites subzone beds of the base of the Denley form the top of the waterfall. Immediately succeeding these, one can see the typical fine-grained calcisiltite beds of the lower Poland Member in the stream bed. About 50 feet of Poland and about 52 of Russia are incompletely exposed over a long distance upstream. About 55-60 feet of Utica shale outcrops farther upstream after about 30 feet of covered interval. Beneath the Trocholites subzone in a stepwise fashion the Sugar River Limestone is fully exposed with the 9 foot thick Rathbun Member at the top. Note the shelly calcarenites of the Rathbun contrasting with the non-shelly calcarenites of the lower member of the Sugar River below and the Poland above. Also note the relatively thick calcisiltite beds of the Rathbun which contrast with the lower Sugar River and show similarities with the Poland above.
Return to cars. Be sure gate in barbed wire fence is closed!

STOP 5. Bridge at Trenton Falls Gorge
Walk across road (watch for traffic) and down to the exposures along the east bank just upstream from the bridge.
About 13 feet of Middle Poland limestone and thin shales are exposed upstream from the bridge on West Canada Creek. Note that the middle Poland is coarser grained and more fossiliferous than the lower Poland at Rathbun Brook (Stop #4). Burrowed fine-grained limestones are still characteristic of this member, however.

STOP 6. Lower Trenton Falls Gorge
Walk about 200 yards down this gravel driveway to the exposures by the powerhouse at its end.
Poland (about 50 feet thick) and Russia (about 75 feet thick) members of Denley limestone can be seen on the opposite bank from the road at the powerhouse. Two reentrants 9 feet apart in the upper Poland represent metabentonites. At the powerhouse gate, the Poland-Russia contact is about 12 feet above the road. The coarser-grained, more rubbly, burrow-reworked, more fossiliferous Russia Member can be examined along the hillside exposures on the walk back to the cars.

STOP 7. Dam at Trenton Falls Gorge
Walk back to road and go uphill, walking around fence gate (opening on left side slightly concealed). Continue uphill for about a quarter of a mile to the dam.
The lower Steuben Limestone and much of the Rust Member of the Denley Limestone can be seen after crossing the dam. By the spillway, the 26 feet of massively bedded, horizontally and cross-laminated, encrinitic Steuben Limestone can be examined from the top of the dam. The contact with the Rust is clearly visible from the reservoir and in the spillway wall. In the spillway, the slump structures in the upper Rust can be examined. Below the spilling the very fossiliferous calcarenites of the upper part of the 115 feet of Rust are excellently exposed. See text above for a detailed description of the Rust at this exposure.

D: GLACIAL GEOLOGY OF THE NORTHERN CHENANGO RIVER VALLEY
Donald H. Cadwell
Regional Setting
The field trip area (Fig. 1) is located in the northern reaches of the Chenango River, a tributary of the Susquehanna River drainage system. The region is covered by parts of the Munnsville, Morrisville, Hamilton, Earlville, Norwich, Sherburne, and Holmesville 7.5 minute U.S.G.S. topographic quadrangles. The area has a total relief of 980 ft (1000 to 1980 ft). The bedrock is predominantly Devonian shale, siltstone, and sandstone (Broughton, et.al., 1962).

Valley Heads moraine
This road crosses the valley train of the Valley Heads moraine. Note the many kettles.

Crest of Valley Heads Moraine
The crest of the Valley Heads moraine is immediately south of town; all drainage in this area is north into the Mohawk Valley.

Clay beds are ponded lacustrine deposits
The clay beds 1 mi north of Pratts Hollow are ponded lacustrine deposits formed during the retreat of the ice from the Valley Heads moraine.

STOP 1. Valley Heads Moraine Exposure
This is an exposure of glaciofluviatile and glaciolacustrine sediments in an ice contact zone. These materials, therefore, were deposits adjacent to large blocks of ice.
In this pit there are examples of several depositional environments: horizontally stratified sands and gravel, cross-bedded sands and gravels with 10 ft of relief, finely cross-bedded sands, and clays dipping northward at the north side of the exposure.
The lithologies in this pit are of typical Valley Heads composition. The provenance of the exotics indicates a source from the Adirondacks and Canada.
Percentage composition:
9% | red sandstone
26% | limestone and chert
39% | locals
26% | exotics

STOP 2. View of Valley Heads Moraine
This is a view of the Valley Heads moraine area. This is the Stockbridge valley, with the towns of Stockbridge and Munnsville to the north. The stratified drift of the Valley Heads moraine is not limited to the Stockbridge valley as well data suggests there is at least 220 ft of sand and gravel in the uplands on the west valley wall.
A question remains as to when and how this moraine was formed:
Hypothesis 1: This moraine was formed as a recessional moraine during the retreat of the same ice sheet that deposited the glacial features to the south, between Binghamton and Earlville.
Hypothesis 2: This moraine was formed during a readvance of the ice; a readvance of a Late Woodfordian ice sheet.

Highest level of the Valley Heads moraine.
Note the large boulders in exposures along the east side of the road.

Valley train materials
Valley train materials that grade to the south away from the Valley Heads moraine.

Kame terrace along the west valley wall.
This kame terrace is 40 ft higher than the Valley Heads valley train.
Is there a relation between this kame terrace and the Valley Heads terminal moraine?
Was this terrace formed during a glacial episode previous to the Valley Heads?

STOP 3. Bradley Brook Ice Margin
This stop illustrates the character of an upland ice margin, see also Figures 3 and 4 in the text. Bradley Brook flows to the east and stratified drift is exposed along the north-facing hillslope. Ablation till mantles the south-facing slope.
The spring near the exposed face west of the road has good drinking water. PLEASE BE CAREFUL TO KEEP IT THAT WAY as several persons still obtain their drinking water from this spring.
The stratified drift was deposited during wastage of an upland ice margin. The sediments are subhorizontally stratified, with perhaps a slight dip to the east. The materials were deposited lateral to the ice and the valley walls, as meltwater flowed to the east in the Bradley Brook valley toward the Chenango River. See also Plate 1.
With continued retreat of the ice front into the next valley to the north, a thin veneer of dead ice remained on the south-facing slope in the Bradley Brook valley. The dead ice deposited a thin ablation till on a perhaps much thicker lodgment till.
The lithologies include red sandstone, lime•stone, chert, igneous and metamorphic exotics, and local sandstones, siltstones and shales. The percentages are:
17% | red sandstone
19% | limestone
47% | locals
18% | exotics

Sand, gravel, and till can be seen in road cuts to the right.

Sand, gravel, and bedrock are exposed to the right.

Kame terrace and esker
While descending this valley wall note the kame terrace and esker. This terrace is 40 ft above the valley floor.
Note the kame and kame terrace on the opposite (east) valley wall.
These kames and kame terraces were deposited when meltwater streams flowed between the ice and the valley walls. At this time there was an ice tongue in the valley extending at least several miles to the south. Additional diagram in the text (Fig.2).

Kame delta units to the right.
This is an exposure in one lobe of a delta. There evidence for lobes in adjacent areas.

Hummocky, stagnant ice topography behind the Sandy Acres Farm.

STOP 4. The Bundy Concrete Company
This pit contains one of the most useable sand and gravel deposits in Chenango County and has been in operation for about 50 yrs. There are local zones and layers of sand and gravel that are cemented. The cemented arch is disintegrating rapidly: two years ago the pillars were twice as thick.
All of the gravel is bright and exotic rich. There are, however, dull sections that result from an increase in the percentage of clays.
Percentage composition:
bright
19% | red sandstone
26% | limestone
34% | locals
21% | exotics
duller
31% | limestone
Problem 1: What is the origin of the cemented zones?
Problem 2: When did cementation occur? immediately postglacially? Recent?

The bedrock hills to the right and behind you are umlaufbergs.
The bedrock hills to the right and behind you are umlaufbergs. These are bedrock hills within the Chenango River valley and are entirely surrounded with stratified drift.
This road traverses several good examples of kame terraces. Others can be seen along the west valley wall.

Entrance into the Whapanaka State Forest
You are on the correct road if just after the turn you see two old railroad tank cars in the weeds to the left.
Entrance into the Whapanaka State Forest and the State Forest Truck Trail.

STOP 5. State Forest Frost Wedge
Walk up into the bedrock quarry. This pit is used by the State for maintenance of the truck trails. The face of the exposure is oriented N20E along one of the joint planes. The frost wedges are developed along the other joint plane N75W.
One frost wedge is well developed. A second wedge, to the north, is partially developed.
Results of digging along the upper surface of the well developed wedge indicate the feature persists with depth. It is known to persist for at least 3 ft to the east.
What is the origin of these features?
Hypothesis-1: That these frost wedges formed during more rigorous climatic conditions after the retreat of the last glacier.
Hypothesis 2: That these frost wedges resulted from several cycles of rigorous climatic conditions and perhaps from several ice advances.
Hypothesis 3: That these are not really frost wedges, but are frost cracks or some other periglacial phenomena.
Hypothesis 4: (This hypothesis was proposed by two local farmers) that these features formed as a result of a series of gas explosions, while man was drilling for oil and gas.

Cross the Chenango River. The umlaufberg is to your right.
The next stop is in the sediments deposited at the southern tip of the umlaufberg.

STOP 6. Chenango County Sand Pit
This is the best sand pit in Chenango County.
The upper section of this pit is composed of lake silts, sands and clays, with many ripple drift laminations. These are well stratified.
The lower section is elusive. It may not be well exposed at the time of the trip; however, it is there. In this section there are examples of strata with vertical bedding; horizontal bedding that abruptly ceases into an unstratified zone; and cross-bedded sands with inclinations of up to 85 degrees. We may have to dig to re-expose these features. See Plates 2, 3,and 4, elusive contorted, discontinuous, vertical bedding in pit.
The lithologies present include red sandstone, limestone and chert, local sandstone, siltstone and shales, and igneous and metamorphic exotics.
Percentage composition:
Hypothesis 1: The lower section was deposited as a kame terrace lateral to a
retreating ice mass. There was an ice readvance causing the rotation of blocks and the discontinuous units. Subsequent to the ice readvance there was a lake followed by the development of the upper lake units.
Hypothesis 2: There was ice adjacent to the lower unit during sedimentation. With the melting of the ice some of the sediments were rotated, while still frozen. This could explain the rotated and discontinuous blocks, and also those with high inclinations. A lake then developed above these sediments.
Hypothesis 3: Some outrageous hypothesis.

STOP 7. Cossitt Concrete Products, Inc.
This sand and gravel pit has the largest drag line operation in the Chenango River valley area.
Exposures in this pit illustrate the following environments of deposition: deltaic foresets; lake bottom units; braided stream deposits; and evidence of deposition near an ice margin--as faulting and slumping in an ice contact zone.
The lithologies include: red sandstones, limestone and chert, local sandstones, siltstones and shales, and igneous and metamorphic exotics.

STOP 8. Hitchcock Sand and Gravel Pit
This pit is a large delta complex of sand and gravel.
This delta formed in a lake that existed between the ice tongue in the Hamilton valley and the ice at Moraine Lake. The Moraine Lake ice was a slowly melting remnant ice tongue whose source had been cut off.

STOP 9. Picture Stop - Hitchcock delta and Hamilton Valley
This is a view of the Hitchcock delta and the Hamilton valley.

E: GEOLOGY OF THE CANADA LAKE NAPPE, SOUTHERN ADIRONDACKS
James McLelland
Colgate University
The results of the present study (1965-1972) show that the southern Adirondacks are underlain by at least one regional isoclinal structure (Canada Lake nappe) that has been folded about several other axes. There probably exist three major periods of folding and each has occurred on a large scale. Axial traces can be followed over tens of miles. Two of the fold events (Fl and F2 ) appear to be coaxial and trend NW with a gentle plunge to the SE. The other is a NE trending fold (F? ) whose existence is postulated in this report. In addition to these folds there exists at least one other event (F3) that has resulted in gentle warping of all other axes.
Locations of the stops were obtained by turning Figure 8 into a Google Earth overlay, manipulating it to accommodate the differences in projection, etc., and then estimating the placemark locations. This was necessary as the caption read: "Fig. 8. Location of stops in Road Log. A complete log with mileage will be found in NEIGC Guidebook for 1969."

STOP 1. The Peck Lake Formation
Roadcut of garnetiferous quartz-biotite-oligoclase gneiss. Minor amphibolite and calc-silicate bands. These gneisses are the dominant lithology of the Peck Lake formation which is exposed here on the south limb of the F1 fold. Needles of sillimanite and/or fibrolite can be seen in some specimens.
In a little overhang near ground level there is a minor fold with an axial trend of N50W, plunging 15 SE. Axial plane cleavage and lineation cut across the compositional layering of this fold. It appears that such folding and cleavage are prevalent throughout outcrops of Peck Lake gneiss. Often these features are obscured by poorly developed compositional banding. Polishing and staining reveal both folds and cleavage in many specimens and, therefore, suggest that their abundance vastly exceeds their recognition.
The entire outcrop is a "large minor" fold. Note the change of dip from one end to the other. The accompanying equal area plot is for poles of foliation in this roadcut and in outcrops directly NE of the road.
The lithologies and structures represented in this cut are typical of the Peck Lake formation. It is the structural complexities that make the Peck Lake formation difficult to work with and subdivide. It is, by far, the least competent unit in the sequence.

STOP 2. Royal Mt. pyroxene-quartz-plagioclase gneiss
Just to the south of the road are good exposures of the Royal Mt. pyroxene-quartz-plagioclase gneiss. This locality is near the outer contact of the Royal Mt. unit, and the latter displays its fairly well banded border phase. Most of the banding is due to this amphibolites. Also present are bands and veins of granite and/or pegmatite.
These exposures show a number of interesting features. In the first place boudinage is developed in most of the amphibolite bands. Some of the boudinage represents rather classical examples while other instances seem unusual. Consider the example exposed at the base of the large boulder just inside the woods. This is shown in the accompanying diagram.
Another example is displayed in the ledge at the top of the hill.
Neither of these features replicates the conventional concept of boudinage. Indeed, they give the appearance of igneous disruption. However, the igneous hypothesis is superfluous for these outcrops contain a good many examples of bona fide boudinage which coexist with, and are part of the systems shown above. Furthermore, the igneous hypothesis lacks merit based on the lack of disruption of some extremely thin amphibolite bands. Of course, the country rock may have been near, or at, temperatures of partial fusion. It seems more plausible that cases of peculiar looking boudinage may be of the "chocolate tablet" type (Ramsey, "Folding and Fracturing of Rocks", p. 113). This suggestion gains credence from the observation that some boudins appear to lack extension into a third dimension. In addition to this, some examples of boudinaged folds are present (Ramsey, ibid, fig. 3-59, p. 116). Still another type of boudinage results from systematic offset along shears:
In most cases the shear fractures are barely visible in the country rock. This implies that the quartz-plagioclase gneiss was in a mobile state at the time of shearing.
At the north end of the outcrop, an example of an F1 recumbent fold is observed. The fold axis trends N40 - 50W and plunges gently south. A set of drag folds is developed on the F1 fold.

STOP 3. Contact between Canada Lake and Irving Pond formations
To the south of the road are several small ledges of Canada Lake charnockitic gneisses and associated quartzo-feldspathic rocks. These exhibit the typical pinkish color of weathered outcrops in the woods. Fresh surfaces are generally dark in color.
Proceed north along the old logging road to the north of the paved highway. At the intersection of it with a second logging road (grass covered) enter the woods. Here there are a number of small outcrops of quartzites and quartzo-feldspathic gneisses of the Irving Pond fm.. The contact between the two formations runs approximately along the paved road.
Immediately to the south of the small cliffs discussed above are quartzites and leucogneisses of the Green Lake formation.

STOP 4. Irving Pond fm. at the Core of Canada Lake Nappe
Parking area on west side of road. On the east side of the road, there is an old logging road that goes east for about 1 mile. This road has been marked with tin can tops nailed to trees. At the eastern end of the road there is a tin can top with a square dug out around it. Upon seeing this mark, turn right and proceed directly up the hill.
(1) About 50' up on the hillside there occur good exposures of Irving Pond quartzite and feldspathic quartzite. Interbedded with these are layers of calc-silicate granulites. In this outcrop the pyroxenitic layers are particularly marked. The largest band of calc-silicate runs about 2' above ground level. It strongly resembles a fold (see figure below). However, the feature is a boudin. This contention is supported by the fact that what appear to be drag folds at, and near, the nose of the pyroxenitic layer, have an orientation of N20E, 15 S, whereas tight minor folds in the outcrop trend N60W, 15 SE. The lineation trends approximately N60W, 15 S. It is possible to argue that this shows only that the pyroxenite represents a fortuitously F0 fold. However, the evidence inveighs against this. At other places on the hillside there are features which are definitely pyroxenite boudins. The axes of these boudins trend NS to N20E and plunge down dip southward. A half a day on this hill provides strong evidence that what appear to be tight folds cored by pyroxenites are really elongate boudins.
(2) Proceed on up the hillside. Several minor folds are exposed. These have axes that range from EW to N30W. All Plunge gently(10° -15°) to the south. All have axial planes within the plane of the foliation.
(3) Follow the trail markers to a well exposed EW ledge. Here there is exposed both boudinage and F1 folding, marked by a large layer of calc-silicate. A sketch of these features is given below, and an equal area projection of the poles to foliation is also given.
(4) Exposed in the cliff face are several excellent boudins of pyroxenitic granulite. The boudin axes trend N20E and plunge 10 S. Note the marked similarity between these boudins and the feature at station 1.
(5) Proceed down the hill and over a 20' cliff. In the cliff face one can see a portion of a large fold. Vertical dips trend N40W. Presumably these dips are associated with an F1 fold.
(6) Follow the marked trail to a small ledge where two F1 folds are exposed. These are typical examples of F1 folding. Because of weathering, one can easily measure the axes as N50W, 20S.
Just a few feet father on is station (1). For those not desiring to make the above hike, there are good exposures of the Irving Pond formation a short distance northward along 29A-IO. These show the gradation from pure quartzite into garnetiferous quartzo-feldspathic gneisses near the contact with charnockitic gneisses of the Canada Lake formation. This is the same contact seen at STOP C and at STOP J. Note the excellent development of minor folds with drag folds.

STOP 5 Canada Lake fm.
Large roadcuts in the Canada Lake formation expose typical examples of the charnockitic (mesoperthite gneisses) that comprise this thick and competent unit.
The rocks exposed here are good representatives of Adirondack "syenites" and "quartz-syenites". Not only is this genetic nomenclature misleading, but it is locally incorrect since the present rocks contain some 25-30% modal quartz (most of which is highly strung out).
Compositional layering is not particularly well developed in the Canada Lake charnockites and this observation is consistent with their proposed metavolcanic origin.
Orthopyroxene is locally developed in the roadcuts.
Note the difference in appearance of fresh and weathered surfaces. Also note the strong resemblance of the charnockitic gneisses to the pyroxene-quartz-plagioclase gneisses of the Royal Mt. unit. It is often necessary to employ staining in order to properly distinguish these two lithologies. In stained specimens a hand lens examination often reveals the perthitic nature of the feldspars.

STOP 6 Royal Mt. gneiss on north limb of F1
Across from the Canada Lake Store and Post Office, there is a large ledge of Royal Mt. pyroxene quartz-plagioclase gneiss. As at STOP C, these gneisses tend to be homogeneous except for bands of amphibolite. Unlike STOP C, the evidence here favors igneous disruption of the amphibolite bands. The most satisfactory way of explaining the features seen at road level is by partial fusion of the pyroxene-quartz-plagioclase host rock.

STOP 7. Green Lake fm.
Proceed east along the road between Green Lake (N) and Canada Lake (S). Looking north, note the rugged mountain known as Camelhump. The break between the two humps marks the contact between the Royal Mt. quartz-plagioclase gneiss and the quartz-biotite-oligoclase gneisses of the 29A formation. Green Lake itself straddles the contact between the Royal Mt. gneiss and a narrow band of Green Lake quartzites. Rising above the east shore of Green Lake is a steep hillside of Canada Lake charnockitic gneiss.
At the east end of Green Lake, enter the woods and observe a well exposed section of Green Lake quartzites. Proceeding up the hillside, note the well exposed contact between the microperthite gneiss and the quartzites. Near the base of the hillside is a well exposed F1 minor fold whose axial elements are clearly developed on the weathered quartzite band. This fold has an axial trend of N40W, 10 S. Farther up the hillside, folds in the charnockite have axial trends N50E, 10 S, etc. It is believed that these aberrant orientations are due to the influence of a small metagabbro intrusion that defines the peak of Green Lake Mountain.

STOP 8. Rooster Hill megacrystic gneiss
On either side of the road, new roadcuts provide good examples of fresh and weathered surfaces of Rooster Hill megacrystic gneiss. The megacrysts consist of K-feldspar which occurs most generally as microperthite; however, orthoclase (cryptoperthite?) and microcline are also present. Microcline is best developed where shearing is most intense. Plagioclase is restricted to the groundmass where it occurs as single crystals and as mortar aggregates. Compositionally, the plagioclase ranges around calcic oligoclase. Quartz content ranges from 20-30%. This latter parameter places the rock out of the syenite or quartz-syenite clan to which others have assigned it (Cannon, Miller, & Nelson). Mafics include biotite, hornblende, and orthopyroxene (variable occurrence). Garnet is developed locally. Myrmekite is common. The rock can be assigned a position in the charnockite family.
An interesting feature is the variable appearance of the gneiss on fresh and on weathered surfaces. Furthermore, the color of the megacrysts may be either dark green, pink, or white.
Throughout most of its occurrence, the megacrystic unit remains relatively homogeneous and unbanded. Foliation is usually defined by planes of fracture and mineral flattening and orientation. Locally, banding increases where bands of Peck Lake gneiss occur. This is especially true near the outer contacts. Banding also occurs in the interior, but it is rare.

STOP 9. Peck Lake fm. on north limb of F1
Large roadcuts of biotite-quartz-oligoclase gneiss of the 29A formation. A cursory examination shows that these gneisses are lithologically identical to those seen at stop B. Note the leucocratic character of the apparently anatectic material. Also note the garnets in some of it.
Beginning at the east end of the outcrop, the dips change in a fashion that indicate a recumbent Z-shaped fold whose axis trends N70W and which plunges gently (5°) to the east. Of particular interest is the degree to which lineation and rodding are developed in the outcrop. On some surfaces the foliation is almost obliterated and the texture approaches that of a pencil gneiss. Good examples of F1 minor folds are present.

STOP 10. Northern Contact of Irving Pond and Canada Lake fms.
Stewart's Landing. Along the shores of Sprite Creek are exposures of Irving Pond quartzites and feldspathtc quartzites. In this area quartzo-feldspathic and pelitic layers increase in abundance because of proximity to the contact with the Canada Lake formation charnockitic gneisses. More typical of the Irving Pond unit are the white and rose quartzites in the side of the stream bank. West of the bridge, the percentage of quartzite increases markedly.
Just below the dam, there is a beautifully exposed Z-fold. This fold is rather open, and is thought to represent a minor F2 fold. Drag folds in the outcrop reflect the major fold orientation. Note the development of axial plane cleavage in the fold.
On the west shore just above the dam, clean quartzites contact garnetiferous and biotite rich layers that occur near the outer contacts of the Irving Pond formation. This contact is exposed alongside the dirt road heading uphill. This exposure demonstrates the variable response of different competencies to a given force field.

STOP 11 F1 folded by F2. Axial region of F2
In Sprite Creek below highway bridge. Exposed along the creek are boulders and outcrops of Canada Lake microperthite and charnockitic gneisses. The dark layers are pyrobolic. Both ortho and clinopyroxene occur in the charnockites.
The point of major interest at this stop is the excellent exposure of F1 folds folded along F2 axes. Note the presence of shear slippage along one of the F2 axes. Note also that the F1 and F2 axes appear to be parallel to subparallel. Lineation is strongly developed.

F: PALEONTOLOGICAL PROBLEMS OF THE HAMILTON GROUP (MIDDLE DEVONIAN)
H.B. Rollins, N. Eldridge, R.M. Linsley
The stratigraphy of the Hamilton Group of theMiddle Devonian of New York State was most recently treated in its entirety by Cooper (1930, 1957). The Hamilton Group of the Chenango Valley (see chart 1) consists primarily of fine clastic sediments and occupies a mid position in this wedge shaped body of rock. In the east the wedge is thickest (about 1,680' in Schoharie Valley (Gruban, 1903, p. 213) and it thins to 285' at Lake Erie in the west (Cooper, 1930, p. 121). In the Chenango Valley the Hamilton Group is 1,465' thick (op. cit. p. 121) and has a dip to the southwest of 65-75 feet per mile (op. cit. p. 119). The Hamilton Group lies unconformably on the Onondaga Limestone and is overlain unconformably by the Tully Formation.
In a very crude sense the Hamilton Group of the Chenango Valley is composed of fine-grained black shales and limestones at the base (the Marcellus Formation) and more clastic units in the upper portion (Skaneateles, Ludlowville and Moscow Formations). However within each of these formations there exists considerable variation from true mud shales through siltstones and up to fine-grained sandstones. The nature of the substrate obviously had a great effect on the faunas associated with them. The black shales are typically associated with a Leiorhynchus fauna, gray shales and siltstones with a Tropidoleptus fauna and the fine-grained sandstones are dominated by bivalves.
A more detailed discussion of some of these problems will follow in sections relating to each of the three stops of this trip.

NYSGA 1972 Trip F

Road climbs up onto Kame terrace

Outcrop of Pecksport Shale Member, Hamilton Group, on right

STOP 1. Solsville Member, Marcellus Formation, Hamilton Group
Notes on the Paleontology of the Solsville near Morrisville, New York*
Harold B. Rollins University of Pittsburgh, Pittsburgh, Pa., 15213
*Scientific Contribution No. DEPS-72-23l
Location Borrow pit on east side of Swamp Road, 2.6 miles north of Morrisville, New York. Morrisville, N.Y. 7 1/2' quad.
Stratigraphy
This small borrow pit exposes an extremely fossiliferous section within the Lower Cazenovian Solsville member of the Marcellus Formation. The only detailed stratigraphic study of Hamilton rocks in the Chenango Valley is that of Cooper (1930), who recognized six members of the Marcellus Formation. In ascending order, these are the Union Springs limestone and shale, the Cherry Valley limestone, the Chittenango black shale, the Bridgewater shale, the Solsville calcareous shale and sandstone, and the Pecksport shales and siltstones. Cooper also noted that the Bridgewater, Solsville and Pecksport undergo a facies change to the west of the Chenango Valley and are there collectively represented by the dark gray Cardiff shale. A detailed study of this facies complex has never been undertaken. This locality is situated beyond the western extremity of the Solsville as delimited by Cooper (1930). Some of the faunal elements are, however, distinctively Solsville, again according to Cooper. These include Nephriticeras maximum, Paracyclas lirata, Gosselettia triquetra, and Cornellites flabellum. It was primarily on the basis of this faunal assemblage that Rollins, Eldridge and Spiller (1971) considered this exposure to be in the Solsville facies.
Fig. 1 presents a very generalized stratigraphic section of the Solsville at this locality. Note the indicated layers of fossil shell concentrations.
Paleontology
This locality has, in the last few years, contributed much to our knowledge of the paleontology of the Hamilton Group. Preservation of the fossils at this locality is perhaps unsurpassed anywhere in the Middle Devonian of New York State. For example, the molluscan shell microstructures are still preserved. Even ghost structures of originally aragonitic shell material can be discerned under thin section and polished-etched slab examination (Rollins, Eldredge and Spiller, 1971). If you carefully examine shell fragments of the large bivalve Gosselettia triquetra, you can see with the naked eye preservation of coarse prismatic shell layers. Naturally etched surfaces of Cornellites flabellum quite often also display coarse shell microstructure. This exposure has also provided the earliest occurrence of preservation of the body of a tubiculous spionid polychaete worm (Cameron, 1967). The worm was interpreted as commensal with the bivalve Cornellites flabellum (Hall). Shell borings of this polychaete are also common in specimens of Spinocyrtia granulosa, Gosselettia triquetra, etc., especially in the upper terrace of the exposure. Apparently, only the epifaunal organisms were colonized by this polychaete. The worm tubes are not found on the infaunal bivalves, such as the nuculids. A coaction, perhaps commensal, is indicated, rather than post-mortem colonization of the host shells by the worms.
Critical stages in the evolution and dispersion of the trilobites Phacops iowensis and Phacops rana were preserved in this small exposure, as discussed by Eldredge (1972, and elsewhere in this guidebook).
Also found at this locality is one of the best preserved and most diverse molluscan faunas in the Hamilton rocks of Central New York State. To date, only the gastropods and monoplacophorans have been studied in detail (Rollins, Eldredge and Spiller, 1971). The pleurotomariacean Bembexia sulcomarginata (Conrad) is very abundant, and can be found throughout the entire exposed section. Spiller (unpublished ms, 1971), following factor analysis of populations of B. sulcomarginata, has determined that this species exhibits sexual dimorphism.
Excellent specimens of Ruedemannia trilix (Hall), another pleurotomariacean, can be obtained from the upper terrace of this exposure. Ruedemannia is considered ancestral to the very common and well-known Worthenia of the Upper Paleozoic.
The lower dark calcareous shales at this locality have provided most of the available specimens of the unusual bellerophontacean gastropod Praematuratropis ovatus (Rollins, Eldredge and Spiller). This little snail is interesting for at least two reasons. First, it retains throughout ontogeny a very pronounced median keel that would have drastically restricted the available space within the shell and presumably would have made impossible total retraction of the cephalopedal mass. This, in conjunction with an extensive inductura, suggests that this gastropod had an internal shell. Secondly, Praematuratropis ovatus is one of the few Hamilton forms "missed" by the great James Hall in his monographic treatment of the Paleontology of New York.
Near the top of the exposure can be found slabs of a highly weathered calcareous siltstone which contains beautifully preserved molds, largely mollusks. The greatest diversity of gastropod species was recognized from this thin interval. Diligent collecting should provide you with a rare specimen of the monoplacophoran Cyrtonella mitella (Hall), complete with internal mold, preserving the muscle scars. A complete tabulation of the gastropods found to date at this exposure is included in the accompanying faunal list.
It should not be assumed that the paleontological potential of this little borrow pit in the Solsville has been exhausted. The beautifully preserved bivalve fauna has not yet been carefully studied, for example. Also of interest is the occurrence of epizooites. If you look closely at some of the brachiopods and mollusks you collect, you'will see epizoic bryozoa, corals, and inarticulate brachiopods, besides the aforementioned worm borings. Gastropod-bryozoan symbiosis is present from the Paleozoic to the Recent, and is very obvious at this locality.
Partial Faunal List
Peterborough South Quarry
Solsville Member, Marcellus Formation
Hamilton Group
Coelenterata |
| Conularia undulata
Bryozoa |
| Paleschara incrustans
| Hederella filiformis
| Monotrypella abruptus
| Reptaria stolonifera
| Taeniopora exigua
| Aulopora sp.
Brachiopoda |
| Orbiculoidea media
| Lingula delia
| Cupularostrum congregata
| Mucrospirifer mucronatus
| Spinocyrtia granulosa
| Ambocoelia umbonata
| Chonetes scitulus
| Spinulicosta spinulicosta
| Rhipidomella penelope
| Mediospirifer audaculus
| Protoleptostrophia perplana
| Tropidoleptus carinatus
Mollusca - Bivalvia |
| Grammysioidea alveata
| Grammysia arcuata
| Grammysia bisulcata
| Grammysia circularis
| Grammysia obsoleta
| Nucula lirata
| Nuculites oblongatus
| Nuculites cuneaformis
| Cornellites flabellus
| Gosselettia triquetra
| Modiomorpha mytiloides
| Modiomorpha concentrica
| Modiomorpha subulator
| Paracyclas lirata
| Goniophora hamiltonensis
| Leptodesma spinigerum
Cephalopoda |
| Tornoceras discoideum
| Michelinoceras constrictum
| Bactrites aciculum
| Spyroceras crotalum
Gastropoda |
| Bembexia sulcomarginata
| Glyptotomaria (Dictyotomaria) capillaria
| Gyronema lirata
| ?Holopea hebe
| Mourlonia subzona
| Murchisonia micula
| Naticopsis sp.
| Palaeozygopleura hamiltoniae
| Patellilabia (Phragmosphaera) lyra
| Platyceras (Platyceras) erectum
| Platyceras (Platyostoma) sp.
| Praematuratropis ovatus
| Ptomatis rudis
| Retispira leda
| Ruedemannia trilix
| Sinuitina brevilineatus
| Trepospira (?Angyomphalus) peneglabra
| Tritonephon rotalinea
Monoplacophora |
| Cyrtonella mitella
Arthropoda |
| Phacops rana
| Greenops boothi
| Echinocaris sp.
Echinodermata |
| Ancyrocrinus spinosus

STOP 2 "Pierceville" Quarry (Bradley Brook Quarry)
Paleoecology of the Ludlowville Formation, Hamilton Group
By R. M. Linsley
This quarry exhibits three distinctive facies of the Ludlowville Formation. The lowest unit (the Chonetes facies) is exposed in the front ledge of the quarry nearest Soule Road and consists of about fifteen feet of dark gray shale with small amounts of silt. Faunally this unit is dominated by brachiopods, and the total faunal content will be discussed more fully later. Lying on top of this unit is a thin (six inch) calcareous shale unit (the Spinocyrtia facies). This unit is exposed in a very low ledge about twenty feet back from the front face of the quarry. It consists of densely packed brachiopods (Spinocyrtia, Athyris and Mucrospirifer). calcite from the shells of these animals has permeated the surrounding sediment and transformed what was probably a fairly soft shale into a durable, hardened calcareous shale. The uppermost unit (the bivalve facies) is exposed in the upper quarry floor and the back wall of the quarry. This unit is a fine grained siltstone and the fauna is dominated by a wide variety of epifaunal and infaunal bivalves.
Partial Faunal List Pierceville Quarry
Ludlowville Formation, Hamilton Group
Coelenterata |
| Aulopora elleri
| Favosites sp.
Bryozoa |
| Sulcoretepora incisurata
Brachiopoda |
| Petrocrania hamiltoniae
| Lingula punctata
| Lindstroemella aspidum
| Oehlertella pleurites
| Mucrospirifer mucronatus
| Spinocyrtia granulosa
| Mediospirifer audaculus
| Ambocoelia umbonata
| Athyris spiriferoides
| Tropidoleptus carinatus
| Rhipidomella penelope
| Protoleptostrophia perplana
| Devonochonetes coronatus
| Longispina mucronatus
| Devonchonetes syrtalis
| Chonetes vicinus
| Spinulicosta spinulicosta
| Cyrtina hamiltonensis
| Elytha fimbriata
Mollusca -Bivalvia |
| Solemya vetusta
| Orthonota undulata
| Grammysia bisulcata
| Grammysia arcuata
| Grammysia cuneata
| Grammysia globosa
| Nucula corbuliformis
| Nucula opima
| Nucula lirata
| Nuculites oblongata
| Nuculites triqueter
| Palaeoneilo constricta
| Palaeoneilo emarinata
| Palaeoneilo fecunda
| Palaeoneilo muta
| Palaeoneilo plana
| Parallelodon harniltoniae
| Actinoptera decussata
| Actinoptera. boydi
| Cornellites flabellus
| Leiopteria sayi
| Leiopteria rafinesquii
| Aviculopecten fasciculatus
| Lyriopecten rnacrodontus
| Pterinopecten undosus
| Modiomorpha cencentrica
| Modiomorpha mytiloides
| Pholadella radiata
| Cypricardella tenuistriata
| Cimitaria recurva
| Goniphora hamiltonensis
Gastropoda |
| Ptomatis rudis
| Naticonema lineata
| Palaeozygopleura hamiltoniae
| Ruedernannia trilix
| Platyceras sp.
| Dictyotomaria capillaria
Cephalopoda |
| Tornoceras discoidea
| "Orthoceras" sp.
| Spyroceras crotalurn
Hyolithida |
| Hyolithes neapolis
Tentaculitida |
| Styliolina sp.
Arthropoda |
| Greenops boothi
| Phacops rana
| Dipleura dekayi
| Echinocaris punctata
| Rhinocaris columbina
Annelida |
| Taonurus
Plants |
| Protolepidodendron sp.

STOP 3. Moscow Formation, Hamilton Group
Notes on the Trilobites of the Hamilton Group of the Chenango Valley Region
Niles Eldredge
The American Museum of Natural History
There are but three trilobite species commonly occurring in the Hamilton Group in the Chenango Valley region: Phacops rana (Green, 1832), Greenops boothi (Green, 1837), and Dipleura dekayi (Green, 1832). As indicated, these three species were among the first trilobites to be described in North America, and with the possible exception of Elrathia kingii (Meek) from the Middle Cambrian Wheeler shale of Utah, one of these -- Phacops rana --has come to be perhaps the most familiar of all trilobites of this continent.
All presumably valid trilobite species of the Hamilton Group of New York are listed in Table 1. A comparable list for the midwest is given by Stumm (1953). Hall and Clarke (1888) remains the most complete and indispensable source of information on the morphology of these trilobites. Of the remaining species not mentioned above, only the proetid Dechenella rowi (Green, 1838) is likely to be encountered in the Chenango Valley area, especially in the Stone Mill limestone exposed in the quarry along Roberts Road in West Eaton. This and other remaining taxa will be discussed only insofar as they bear on the biogeography and provenance of the Hamilton fauna.
Partial Faunal List
Deep Spring Quarry
Moscow Formation, Hamilton Group
Bryozoa |
| Stictopora
| Reptaria stolonifera
Brachiopoda |
| Lingula Eunctata
| Rhipidomella penelope
| Tropidoleptus carinatus
| Cupularostrum congregata
| Devonochonetes coronatus
| Atrypa "reticularis"
| Ambocoelia umbonata
| Elytha fimbriata
| Mucrospirifer mucronatus
| Spinocyrtia granulosa
| Athyris spiriferoides
Bivalvia |
| Grammysioidea alveata
| Grammysia arcuata
| Grammysia bisulcata
| Grammysia elliptica
| Grammysia cuneata
| Grammysia globosa
| Grammysia lirata
| Grammysia constricta
| Orthonota undulata
| Tellinopsis subemarginata
| Parallellodon hamiltoniae
| Palaeoneilo muta
| Nucula corbuliformis
| Nucula opima
| Nucula bellistriata
| Nucula lirata
| Nuculites oblongatus
| Prothyris lanceolata
| Cornellites flabellus
| Aviculopecten fasciculatus
| Actinoptera decussata
| Actinoptera boydi
| Pterinopecten undosus
| Leiopteria rafinesquii
| Glyptodesma erectum
| Modiomorpha concentrica
| Modiomorpha mytiloides
| Goniophora rugosa
| Cypricardella bellistriata
| Paracyclas elliptica
| Sphenotus truncatus
Gastropoda |
| Mourlonia lucina
| Dictyotomaria capillaria
| Platyceras sp.
Nautiloidea |
| Spyroceras crotalum
| Paradiceras
Hyolithida |
| Hyolithes ligea
Arthropoda |
| Phacops rana
| Greenops boothi
| Dipleura dekayi
| Echinocaris punctata
Plants |
| Protolepidodendron sp.

G: PALEOECOLOGY OF A BLACK LIMESTONE, CHERRY VALLEY LIMESTONE, DEVONIAN, NEW YORK STATE
John Cottrell
University of Rochester
The Cherry Valley Limestone is documented in the literature as early as 1842 when Vanuxem referred to the "Goniatites" or "Agoniatites Limestone" of the Marcellus Formation in his publication of Geology of New York: Third Geologic District. In 1903. Clarke proposed the name of Cherry Valley Limestone for the "Agoniatites Limestone"; named for the excellent exposure in Cox's Ravine just south of the village of Cherry Valley. This section was presumed to be typical of the Marcellus Formation throughout western New York.
The Cherry Valley Limestone is known to extend for 160 miles across central New York from its westernmost outcrop in Flint Creek near Phelps, Ontario County to the easternmost outcrop in Onesquethaw Creek near Clarksville, Albany County. The Cherry Valley overlies the Union Springs Member of the Marcellus Formation and is capped by the Chittenango Shale Member. To the east the Cherry Valley grades into the Stoney Hollow Sandstone and to the west joins with the upper beds of the Onondaga Limestone.
Perhaps the Cherry Valley is best known for its unique assemblage of cephalopods as documented by Flower (1936). Previous work has been done mainly by Clarke (1901), Grabau (1906), Cooper (1930,1933), Smith (1935), Flower (1936, 1943), and Rickard (1952).

NYSGA 1972 Trip G

The Cherry Valley Limestone outcrops for several hundred feet along the roadside and is one of the most extensive outcrops available for study. This location was chosen as the type section for the study conducted during the summer of 1968. The contact hetween the Cherry Valley and the Union Springs member below is gradational over a distance of 0.2 feet. The lowermost portion of the Cherry Valley contains abundant brachiopods and ammonoids. It is a medium grained dark gray skeletal limestone separated from the middle beds by a thin zone of Aulopora. The central unit is a nodular bed composed of medium grained limestone interbedded with argillaceous layers. The limestones, up to 0.6 feet thick, are broken into nodules; a case of sedimentary boudinage. The central unit is only slightly fossiliferous. The zone above the central unit is similar to the basal unit in that it contains a thin zone of Aulopora which separates it from the massive bed above. The uppermost unit of the Cherry Valley is a massive medium to coarse grained limestone with abundant orthocone nautiloids and brachiopods. The brachiopods found in the uppermost layers vary from those found in the basal layers. The Cherry Valley is gradational with the shales above which are extremely fossiliferous with brachiopods and bryozoans.

The Cherry Valley Limestone has thinned from a thickness of 4.2 feet at the type section to 2.9 feet at this Gulf Road section. Again the Cherry Valley is gradational from the underlying shales and cephalopods and brachiopods are present in the lowermost layers. Here we see the first introduction of trilobites to the Cherry Valley fauna. Fragments of cephalon, thorax, and pygidium can be found in the lower unit. The Aulopora zone at the top of the lower unit is not as well defined, and Aulopora seems to be present within the middle unit only. The middle unit has thinned from 1.9 feet at the type section to 0.8 feet and retains its nodular appearance. A few brachiopods and Aulopora comprise the fauna of the middle unit. The upper unit is gradational from the overlying shales and contains abundant brachiopods and cephalopods. It is a fine to medium grained black limestone with some replacement of shell material with coarse grained rusty calcite. The shales and limestone layers of the Union Springs member below show some evidence of folding.

The Cherry Valley Limestone outcrops for several hundred feet along Falls Road and along the banks of Oneida Creek. The thickness of the section fluctuates between 2.1 and 2.8 feet with the greatest variation being seen in the upper unit. Again trilobites are present in the lower unit and crinoids make their first appearance in the western sections. They appear as single crystals of calcite in the medium grained black limestone of the lower beds. Brachiopods and cephalopods also comprise the fauna of the lower beds. The middle unit is separated from the upper and lower units by irregular surfaces and maintains its nodular appearance. A few brachiopods and Aulopora are the only noticeable fauna. The upper unit consists of a fine to medium grained limestone which grades into the shales above. Cephalopods and brachiopods are abundant.

The final stop on the field trip is perhaps the most picturesque. The Cherry Valley Limestone outcrops in a stream bed approximately 300 yards from the road. Actually two outcrops may be seen at this location as the stream splits and allows for two exposures, The left branch of the creek offers the better section. The lower unit of this section is a fine grained black to brown limestone with a fauna consisting of mainly brachiopods and trilobites. Some evidence of crinoids is seen in single crystals of calcite within the fine grained limestone. The large ammonoids and orthocones are missing from the fossil assemblage. The middle unit consists of a nodular black fine to medium grained limestone with apparent secondary calcite replacement. There are few fossils present and some very thin shaley interbedding. The upper unit consists of a basal bed which closely resembles the middle unit in lithology. It has the nodular appearance of the middle unit yet lacks the shaley interbedding. It has a scattered fauna of brachiopods and corals. The middle layer of the upper unit is the most fossiliferous with abundant brachiopods and cephalopods. Corals and crinoids are present also. The uppermost layer of the Cherry Valley is a dense fine grained black limestone gradational from the shales above. Very few fossils are present.

H: SEDIMENTARY ENVIRONMENTS AND BIOSTRATIGRAPHY OF THE TRANSGRESSIVE EARLY TRENTONIAN SEA (MEDIAL ORDOVICIAN) IN CENTRAL AND NORTHWESTERN NY
Barry Cameron, Stephen Mangion, and Robert Titus
Dept. of Geology, Boston University
The fossiliferous marine limestones and shales of the Ordovician Trenton Group of New York has been studied by many paleontologists and stratigraphers for well over 150 years. Along with the underlying Black River Group (fig. 2), it has become well-known among geologists as part of the medial Ordovician standard reference section of North America. However, the geology of the Trenton Group still poses several relatively complex problems of interpretation for the application of stratigraphic, paleontologic, and paleoecologic principles. Specifically, there is still "•••confusion and disagreement regarding the correlation of the upper Black River and lowest Trenton in New York and Ontario" (Kay, 1942, p. 599) (see also Fisher, 1962; Textoris, 1968; Cameron, 1969a, 1969b; Walker and Laporte, 1970).
The modern approaches to the paleoecologic study of carbonate rocks, such as sedimentary petrography (Cameron, 1968), fossil community analysis (Porter and Park, 1969; Park and Fisher, 1969, Cameron and Mickevich, 1972), population paleontology (Ross, 1967), primary sedimentary structures (Chenoweth, 1952; Cameron, 1968), have just recently been applied with emphasis to parts of the medial Ordovician Trenton group of central and northwestern New York. Many previous investigators who have studied these formations have been, by necessity, primarily concerned with lithostratigraphy, such as statistical analysis of rock types (especially Chenoweth, 1952, and Lippitt, 1959), biostratigraphy and correlation, and mapping.
Although many faunal lists have been made for the New York sections (e. g., Cameron, 1968; Fisher, 1957; Chenoweth, 1952; Kay, 1953, 1937, 1933), most major fossil groups are in need of thorough restudy, using modern paleontologic approaches and techniques. However, a few groups in New York have received careful attention and revision in recent years. These include the Brachiopoda (Cooper, 1956), Ectoprocta (Ross, 1964, 1967), conodonts (Schopf, 1966), and calcareous algae (Cameron and Awramik, in preparation).
This field trip will illustrate and summarize a detailed time, lithic, and faunal microstratigraphic framework for the lower Trenton Group, i.e., the Rocklandian, Kirkfieldian, and Shorehamian stages, in central and northwestern New York. The limestones of the upper Black River Group beneath the lower Trenton Group will also be examined at several stops. This will then form the basis and provide the confidence for reconstructing the environments of deposition and determining the paleogeography. Special emphasis will be placed on statistical analysis of the rock types both from detailed field measurements and carbonate petrography, small scale physical and biological correlation, primary sedimentary structures, trace fossils, fossilization, and fossil community analysis. This information should better document the initial and subsequent wider transgression of the Trentonian sea.
The specific purposes of this field trip are to:
1) Demonstrate the stratigraphic succession and its lateral variations.
2) Discuss and evaluate the age relationships and time correlations of the various formations by
a) Examining the diverse faunas and
b) Demonstrating the lateral continuity of major lithic and biologic characteristics.
3) Examine and evaluate the criteria for determining the extent and significance of the disconformity along the Black River-Trenton boundary.
4) Examine and evaluate the criteria for determining the conditions and environments of deposition and paleogeography.
5) Examine fossilization and reconstruct fossil communities
6) Determine temporal and spatial relationships between fossil communities and sedimentary environments in a transgressive sequence.
This field trip guide will summarize previous work on the lower Trenton Group in the Little Falls Port Leyden and surrounding 15' quadrangles and incorporate new data in support of reinterpretations of the stratigraphy and sedimentary environments of the lower Trenton Group in this area. The Little Falls quadrangle is located along the southwestern margin of the Adirondack Mountains and is included in southern Herkimer County. The Port Leyden quadrangle is located in Oneida County north of Boonville, New York, west of the Adirondacks. Good exposures of medial Ordovician limestones are to be found along the Mohawk River, East Canada Creek, West Canada Creek, and Black River valleys and those of their tributaries. Stops for this trip are located in the quadrangles mentioned. Many small abandoned limestone quarries in the Little Falls quadrangle contain excellent exposures of the Black River-Trenton boundary.

NYSGA 1972 Trip H

Poor exposures of Napa-nee Limestone on left.

STOP 1. Inghams Mills (Locality #C99):
Walk to right, through the grass, and proceed to the right of the wire fence, walking beneath the power lines.
At the stone wall along the edge of the field, bear left and walk along the wire fence. CAUTION: Poison ivy often grows in abundance along this path.
Opposite the brick building, turn right and proceed very carefully over the boulders and across the creek towards the base of the outcrop. The boulders you will have to walk over to get to this exposure are sometimes unstable and tend to move when stepped or climbed upon. Be careful!
Four medial Ordovician formations are exposed at this outstanding outcrop on East Canada Creek. Lithologies, sedimentary structures, fossil assemblages, formational boundaries and paleoecology will be examined.
Gull River Limestone. About 29.5 to 30 feet of Gull River Limestone are excellently exposed here and overlie the Little Falls Dolomite of late Cambrian age. A thick dove gray shaly limestone is present at the base. Within the lowest 3 feet is a slump breccia which possesses limestone blocks up to 2.5 feet in diameter. This probably formed as a result of instability over the irregular depositional surface of the Little Falls Dolomite. The next 16.5 feet contain horizontally laminated (algal?), dove gray calcilutites with abundant vertical burrows (Phytopsis), a few ostracods, and frequent stylolites. Frequent mudcracks confirm an intertidal or lagoonal origin.
Thin shales are common in the lower 10 feet. The folded limestone layers reported by Cushing (1905a, pl. 6) from the lower Gull River Limestone at this exposure apparently formed as a result of settling over compacting thick shale lenses (Cameron, 1969b, fig. 6).
Between l6.5 and 22.5 feet an apparently subtidal, irregularly burrowed essentially non-laminated, massively bedded, dark gray to black calcisiltite zone contains Foerstephyllum halle, Lambeophyllum profundum, Hormotoma, Loxoplocus, Isotelus, cryptostome bryozoa, straight nautiloids, and pelmatozoan debris. Most of these species were interpreted as being subtidal by Walker and Laporte (1970).
Immediately above these deeper water sediments, the intertidal or lagoonal facies begins to reappear. This is a vertically burrowed, horizontally laminated (algal?), limestone intraclast-bearing, fossiliferous calcilutite and calcisiltite zone. Fossils from this interval include Tetradium cellulosum, Eoleperditia fabulites, Lambeophyllum profundum, Isotelus, cryptostome bryozoa, and pelmatozoan fragments. Near the base of this zone a sediment filled tidal meander (?) or channel up to 7 feet wide and 2 feet deep is excellently exposed in two faces of the outcrop. Note the structure and composition of the sediment filling it.
At about 27 feet, a 9 inch thick calcilutite bed contains scores of whole Tetradium cellulosum colonies in life position, representing a wave baffle community as described by Walker (1969). They cover 50% to 90% of the bed which contains a thin veneer of limestone pebble conglomerate. One can readily see how the fine-grained sediment was trapped in and around these delicately branching tabulate corals.
The top of the Gull River Limestone is riddled with burrows (dominantly vertical) partially filled with the black lustrous carbonaceous mineral anthroxolite. Several inches of irregular relief over the top of this bed marks the disconformity between the Black River Group and the Trenton Group.
"Napanee Limestone"-The lowest 13 feet of the Trenton limestones can be divided into 7.5 feet of chocolate brown weathering interbedded calcareous shales and argillaceous calcisiltites above. The contact between these two subdivisions is slightly gradational. The surfaces of the limestone layers exhibit extremely well-developed loading casts. In addition, the lower subdivision contains an unusually well-developed and fully exposed intraformational fold (Fig. 10) similar to those described by Chenoweth (1952) from the Sugar River Limestone in northwestern New York. Fossils are common (see text above) in these protected subtidal limestones.
Kings Falls Limestone -Twenty-three feet of the Kings Falls Limestone disconformably overlies the Napanee (Cameron, 1969b). A polymictic conglomerate (dominantly limestone clasts) and shelly calcarenites mark the base of the formation. The upper contact with the Sugar River is determined by a sharp decrease in brachiopod shell calcarenites and an increase in encrinitic bryozoan rich calcarenites (Cameron, 1969b). These field observations are supported by 5 point moving average curves constructed from point-counts of thin-sections (Fig. 17) and analysis of the lithology of each bed of the Kings Falls and Sugar River Limestone (Fig. 16).
Pararipp1ed and/or conglomeratic shelly calcarenites with some horizontal burrows are common in the first 4 feet of the Kings Falls. The succeeding 19 feet of the formation represents rapidly fluctuating environments. Scour-and-fill intraclasts pararipples and laminated beds indicate shallow waters for most of this interval, but there are several feet of rubbly weathering, burrow reworked strata within this interval that reflect deeper water conditions also.
The brachiopods, especially Dalmanella, dominate the assemblages of the lower 20 feet of the Kings Falls formation at Inghams Mills. Other common brachiopods include Sowerbyella, Dinorthis and the strophomenids. Snails are locally abundant in this interval among these are Hormotoma, Loxoplacus, Liospira and Sinuites. The alga Solenopora was common in the lowest bed but has been overly collected. Other common species of the Kings Falls at Inghams Mills include the trilobite Flexicalymene, the bryozoa Stictopora and one crinoid.
Sugar River Limestone: Fourteen feet of the Sugar River Limestone are exposed. The top of the outcrop at the base of the dam is probably near the top of the pre-Rathbun Sugar River because large Prasopora are found there. At this locality the Sugar River has many relatively massive, laminated beds.
Pararippled, sheet and cross-laminated beds and scour-and-fill structures are common in the lower few feet along with thin-bedded, burrow-reworked zones. Higher up there is an alternation of laminated and burrow-reworked horizons.
Diversities in the Sugar River formation are much lower than in the Kings Falls or in the Sugar River elsewhere. Large colonies of the bryozoan Prasopora and Eridotrypa are common and dominate the assemblages. Snails are absent and brachiopods are much less diverse and abundant. The cryptostome bryozoa and the pelmatozoans are more diverse and common. The trinucleate trilobite Cryptolithus which is the Shorehamian index fossil, is present in the Sugar River. The inarticluates Trematis and Lingulasma are present near the top of the outcrop.

STOP 2. Buttermilk Creek (locality #CI01)
Walk upstream through the edge of the field on the south side of Buttermilk Creek, climb under wire fence, and continue along north bank of stream until you reach exposures of the Trenton Group.
The Gull River, the Kings Falls and the Sugar River (including 5 feet of the Rathbun Member) limestones are exposed here. There are 40 feet of the Kings Falls and 38 feet of the Sugar River Limestones.
Kings Falls Limestone -The Kings Falls disconformably overlies the Gull River. Pararippled, sheet and cross-laminated, horizontally burrowed beds are common throughout the Kings Falls Limestone. A few beds are vertically burrowed and others contain intraclasts. Some intervals have been extensively burrowed causing weathered beds to have a rubbly appearance, especially at the base of the formation. These intervals are uncommon, however, and a dominantly high subtidal environment is postulated.
The contact between the Kings Falls and the Sugar River is again well-defined petrographically by an increase in encrinitic, bryozoan-rich material and an accompanying decrease in brachiopods and sparry calcite cement (Fig. 17). At City Brook, 1/4 mile to the southeast, shelly arenites decrease markedly at 43 feet above the base of the Kings Falls (Fig. 16), and inferentially at about the same level at this locality.
Assemblages of the Kings Falls are numerically dominated by the brachiopod Dalmanella. Few bryozoa and pelmatozoan species occur. The snails Sinuites, Phragmolites, Loxoplocus, and Liospira occur up to 15 feet. Prasopora begins to occur in small numbers at 10 feet.
Sugar River Limestone -From 40 to 49 feet in the section lithologies and sedimentary structures are gradational between the Kings Falls and the Sugar River limestones. This interval is dominated by thin, burrow-reworked beds, however, and is assigned to the Sugar River formation. Pararippled, sheet and cross laminated beds are common and slightly deeper water conditions are inferred.
Above 49 feet there a few laminated beds and thin, burrow-reworked beds dominate except for the top few feet of the formation. Here several relatively massive beds are found in the pre-Rathbun Sugar River which may indicate shallowing waters.
Several feet into the Sugar River formation at the 44 foot level several species begin to appear which seem characteristic of the deeper water environment. Among these are the articulate brachiopod Platystrophia, the inarticulate Trematis, the trilobite Cryptolithus, and the bryozoa Escharopora. These species continue to occur into the top of the Sugar River formation. The pelmatozoans become more diverse and common in these beds. Above 60 feet fenestrate bryozoa and cystoids plates occasionally appear. Large Prasopora occur in the uppermost pre-Rathbun Sugar River.

STOP 3. Small quarry (locality #C105)
Walk along path (an overgrown old dirt road) for about 400 feet to a small quarry.
The purpose of this stop is to examine a black chert-bearing, subtidal "calcisiltite lithofacies" of lower Trentonian age lying between 9.5 feet of Gull River and one foot of Kings Falls limestones (Fig. 3). This 3.25 foot unit is composed of massively bedded, medium gray weathering, irregularly burrowed, dark gray to black, argillaceous, and somewhat conchoidally to brittlely fracturing limestones with irregular wavy bedding surfaces separating 0.5 to 3 inch thick continuous and discontinuous layers. Its contacts with the Gull River below and Kings Falls above are marked by "corrasion" surfaces. Although diagnostic Trentonian macrofossils have not been identified from this exposure, conodonts (Hasan, 1969) indicate a Trentonian age for this facies and a Bolarian age for the Gull River limestones below.
The Gull River limestones are composed of light dove gray to medium gray calcilutites and calcisiltites. Fenestral fabric, horizontal laminae (algal?), limestone intraclasts, stylolites, and thin shale layers are frequent. The vertical burrow 2 is common, while infrequent body fossils only occur within the upper 2.5 feet, including Eoleperditia fabulites, small ostracods, Loxoplocus, strophomenid brachiopods, and Tetradium cellulosum.

Kings Falls Limestone exposures on both sides of Route 12.
Quarry in the distance off to the right across Sugar River in foreground is in the Watertown and Gull River limestones of the Black River Group.

Exposure of upper Napa-nee and lower Kings Falls ls on left side of Route 12.

STOP 4. Sugar River (locality #C2)
Walk back to bridge and walk upstream along the north bank (nearer side) of Sugar River to the railroad bridge.
Four formations are exposed here: the Napanee, Kings Falls, Sugar River, and the Denley Limestones.
Napanee Limestone -The Napanee Limestone formation at this locality is about 20 feet thick and is wholly within the northern shaly calcisiltite lithofacies. The base is under water and the upper contact with the Kings Falls is marked by a prominent 18 inch thick shelly calcarenite bed (Fig. 13). The lower half is dominated by many almost barren conchoidally fracturing calcilutites and calcisiltites several of which are quite thick. Calcarenites occur sporadically throughout but are more common in the upper half. Horizontally laminated calcisiltites are frequent in the lower half, the top of which is marked by a poorly developed pararipple, while the upper half contains frequent shelly sheet laminated beds. Low angle cross-laminations are found in the middle and become somewhat shelly towards the top. The burrow Chondrites and large and small horizontal burrows are present throughout. Note that most of the laminated beds are burrowed at their tops.
The fauna of the Napanee is described generally in the text above. Dalmanella-dominated bryozoan, brachiopod and trilobite assemblages are present. Cup corals may be found at about 10 feet and snails become more common in the upper half of the exposure along with occasional clams.
Kings Falls Limestone -The Kings Falls is 64 feet thick at Sugar River. The lower 12 feet of the formation is of Rocklandian age as indicated by the presence of the upper Triplesia cuspidata assemblage zone (Cameron, 1968). The upper contact with the Sugar River Limestone is drawn at the top of a prominent pararippled bed at the top of the water fall (Chenoweth, 1952). The field boundary corresponds well with the petrographic criteria cited previously (Fig. 17).
The lower 35 of the Kings Falls is dominated by shelly (Fig. 16) cross-laminated, sheet laminated, and pararippled arenites. Horizontal burrows are common but are not dominant. A high subtidal environment is inferred.
The succeeding 29 feet of strata is transitional in character between the Kings Falls and the Sugar River limestones. The bedding continues to be relatively massive and cross-laminated strata are common. Horizontal burrowing is more abundant and shelly arenites are infrequent (Fig. 16). On the whole this interval is most similar to the Kings Falls. Water conditions are probably deeper than in the first 30 feet of section where cross-laminated beds were much more common.
The Rocklandian brachiopod Triplesia cuspidata and the horn coral Lambeophyllum occur in the lower 12 feet of the Kings Falls. The snails, Sinuites, Liospira, Phragmoloites, Subulites, Loxoplocus and Hormotoma gracilus occur up to 2 feet. The brachiopods Dalmanella and Sowerbyella dominate the beds of the lower Kings Falls, but not to the extent observed in the more nearshore outcrops to the southeast. Between 25 and 50 feet the diversity drops, but between 50 and 65 feet the assemblages resemble those of the lower 25 feet.
Sugar River Limestone -The formation is about 40 feet thick at this locality, its type section. The Camp Member (Chenoweth, 1952) of the Denley Limestone (Kay, 1968) overlies the Sugar River and is poorly exposed on the cliffs above the water fall on the north Side of the river. The Glendale Member (Chenoweth, 1952) of the Denley comprises the top of the cliff. The Sugar River is again dominated by thin, burrow-reworked beds. A few cross-laminated beds are occasionally observed. Relatively calm deeper waters are inferred for the Sugar River Limestone.
Deep water species appear in the Sugar River. The bryozoa and pelmatozoa become more diverse and common. The brachiopods Trematis and Platystrophia appear along with the Shoreharnian trilobite Cryptolithus. In the upper few feet of the formation the bryozoa and pelmatazoan diversity drops and the snail Sinuites appears suggesting a shallowing of the water.

I: SYRACUSE CHANNELS: EVIDENCE OF A CATASTROPHIC FLOOD
Bryce M. Hand and Ernest H. Muller
Department of Geology, Syracuse University
Uniformitarianism triumphed over Catastrophism in the days of Hutton and Werner, but skirmishing between modified catastrophist and uniformitarian views has been sporadically renewed down to the present time. Such has been the controversy over the channeled scablands of the Columbia Plateau. Similarly, divergent views have entered into conjecture regarding the meltwater channels south and east of Syracuse --conjecture as to duration of drainage diversion which they record, and as to the relative roles of channel scour and plunge pool migration in their development.
This field trip is planned to present evidence of a limnic hlaup, and episode of truly catastrophic stream erosion and canyon cutting resulting from precipitate down-cutting of a drift dam in Rock Cut Channel. The objective is to present arguments supporting a new look at the Syracuse channels (Muller and Hand, 1972). Very candidly, where the evidence permits alternative interpretations, we shall blandly espouse that interpretation which best fits the view that exceptional catastrophic events as well as normal processes have shaped the channels south and east of Syracuse.
Although the channel system in question was certainly initiated prior to the last major episode of Wisconsin glaciation (Sissons, 1960; Muller, 1964), the focus of this excursion is upon development during recession of the Wisconsin ice sheet and the story begins as the ice margin receded from the Valley Heads Moraine along the southern limits of the field trip route.

NYSGA 1972 Trip I

Drive north on NY 46 and 12B across Valley Heads outwash plain.

Proceed west across Valley Heads outwash plain.
Kames and kettles of early ("advance") phase of Valley Heads Moraine are south of US 20, but the massive, divide-forming moraine ridges are 1.5 miles north. Leave Chenango-Stockbridge trough. Road cuts expose Skaneateles shale members.

Park on shoulder at crest of hill for overview of regional relationships and introduction to meltwater drainage conditions at margin of ice sheet during wastage at the edge of the Appalachian Plateau. Evidence of subglacial and englacial meltwater flow.

Descend steadily northward
Descend steadily northward, passing exposures of Onondaga, Helderberg and Cobleskill Formations. Old Lehigh Valley RR alignment follows meltwater channel east to Cottons.

Postglacial gorge
Constructional topography and thick drift at left ahead fill the former valley of Canaseraga Creek, forcing the creek to cut a narrow rock-walled postglacial gorge through Syracuse Formation and Vernon Shale along Creek Road.

Roadside exposures of red and green Vernon Shale and red shale-crammed lodgment till.

Enter Mycenae.
For approximately the next 3 miles, from Mycenae to Fayetteville, NY 5 follows the well-defined Pools Brook glacial meltwater channel. Inset lodgment till shows a complex history of channel development.

Entrance to Green Lakes State Park
Entrance to Green Lakes State Park, location of Green and Round Lakes, both of which are meromictic and have been the object of intense and diverse limnologic studies. Both are situated in the Green Lake glacial meltwater channel.

STOP 2 Gravel pit on right (west) side of High Bridge Road.
Character and structure of High Bridge Delta built where the High Bridge (White Lake) Channel entered Limestone Trough Lake. Note clast size and dominance of carbonate rocks.

Upper surface of the High Bridge Delta.
For about 0.5 mile from this intersection, the road crosses the constructional upper surface of the High Bridge Delta. During flushing of Rock Cut Channel, the catastrophic discharge escaped eastward through High Bridge Channel. At peak discharge the whole delta may have been covered with water. The main channel is south of the road. Its floor is at about 530 feet above sea level, whereas the top of the delta stands at 600 feet. From this we infer that the water in High Bridge Channel was at least 80 feet deep during delta development.

The road continues along the north side of the main channel
The road continues along the north side of the main channel, occupied by White Lake. Toward the west, the road is located on bedrock.

Descend into scour channel maintained by vortex in lee of Rock Cut Delta.
The near (northeast) wall of this scour channel is bedrock while part at least of the far (southwest) side is the depositional front of the Rock Cut Delta. Delta foreset beds are parallel to the present slope. The material is sand and gravel with boulders several feet in diameter.

Bedrock exposed in roadcut along Maple Drive just north of intersection.

You are now on top of the Rock Cut Delta.
The favored lawn ornaments in this housing development are boulders 4 to 6 feet in dimension. These boulders occur here in delta topset beds at an elevation of 600 feet about 50 feet above the floor of Rock Cut Channel from which they were derived.

Channel developed during catastrophic discharge of Rock Cut Channel
Note the broad channel-like depression to the left (south) on the grounds of the Dewitt Fish and Game Club. This channel is 700 to 1000 feet wide; its axis lies about 35 feet below the adjacent delta surface and slopes gently westward, i.e. up-current. We conclude that this channel developed during catastrophic discharge from Rock Cut Channel, at a time when water level stood near 6OO feet in elevation.
Presumably, most, if not all, of the delta surface was under water at one time, but channels accommodated a disproportionate part of the flow. The situation is similar to, but with less pronounced channelization than in the High Bridge Delta.

Fluvial boulder gravels in road cut on left.
The valley into which we are now descending was cut subsequent to formation of Rock Cut Delta and so transects the delta, isolating the remnant we have just crossed from other remnants west of Butternut Creek.

STOP 3. Heavily worked pit exposing remnants of deltaic structure
Heavily worked pit exposing remnants of deltaic structure, part of the delta built by Rock Cut Channel into Butternut Trough Lake. Note boulder size, northeastward-dipping foreset beds and irregular surface upon which the delta was built. The delta surface is more than 60 feet above the floor of Rock Cut Channel.
In contrast to the material in the delta at Stop 1, black shale is a constituent in the gravel here, though black shale is not present as bedrock north of Rock Cut Channel. We conclude that a) Rock Cut Channel had been carved into bedrock prior to the most recent glaciation; b) Black Marcellus Shale had not yet been stripped from the area north of Rock Cut Gorge at the onset of the most recent glaciation; c) Marcellus Shale as well as 30 feet of Onondaga Limestone was stripped from the plateau margin north of Rock Cut Channel by late glacial erosion; d) some of the glacially eroded debris rich in black shale and Onondaga Limestone was deposited as drift fill within Rock Cut Gorge; and e) catastrophic erosion of the drift-fill dam in Rock Cut Channel delivered this material for deposition in the delta built into Butternut Trough Lake.

Boulder gravel at top of the exposure on the right
Boulder gravel at top of the exposure on the right across Butternut Creek is part of a small remnant of the Rock Cut Delta with its surface at about 610 feet above sea level. The gravel displays crude foreset bedding dipping southeast (to the left, out of the exposure face) and graded bedding. The boulder gravel rests upon finer sediments including both lacustrine silt and sand and lodgment till.

Till in roadside exposure on left contains little or no black shale fragments
Till in roadside exposure on left contains little or no black shale fragments in spite of its location south of Rock Cut Channel from which shale-bearing drift was eroded to build the delta at Stop 3. We hypothesize therefore that during the last glaciation, all black shale north of this position had been removed by the time the glacier had changed from an erosional to a depositional regime.

STOP 4. and LUNCH
North of the parking lot is the steep-walled basin of Green Lake (Jamesville Lake). At the west end, twin channels lead to a lip 175 feet above the lake floor. The lake is about 55 feet deep, with unknown thickness of marl and detritus infilling. Eastward a broad channel leads to Butternut trough. About 100 yards west of Green Lake is the smaller basin of Dry Lake, which also bears the appearance of a plunge basin, occupied for a shorter interval and cut perhaps by smaller discharge. The surrounding rock bench at 710 to 720 feet above sea level is relatively bare of either drift or alluvium. North and northeast of Green Lake are several much smaller basins. All have eastward-opening channels leading to Butternut Trough and all are presently controlled by subterranean outflow. The features of Clark Reservation reflect the work of subglacial and glaciomarginal drainage controlled in part of previously developed and subsequently modified solution features.

Excellent view of Rock Cut Channel.
The view is west, i.e. upstream. The gorge is 2000 feet across from rim to rim. Farther west the gorge narrows slightly, but is never less than 1300 feet across. The flat valley floor, averaging about 130 feet below the rim, is 1000 feet wide. Floor and walls are composed of Upper Silurian and Lower Devonian carbonate rocks. The floor, on Fiddlers Green Dolostone is at 555 feet above sea level.
2012: What used to be Nottingham Road here is now called Ram's Gulch Road, and it does not go across the Rock Cut Channel. The route has been adjusted.

Cross axis of Nottingham Channel at oblique angle.

STOP 5. Nottingham Channel
Nottingham Channel leads from a plunge pool near the southwest edge of the golf course and drained into Butternut Trough Lake. At its outlet it appears to be sealed off by boulder gravels of Rock Cut Delta, presenting the anomaly that though located north of Rock Cut Channel, it seems to have ceased to exist prior to final cutting of the Rock Cut Channel.

The plunge basin behind the trailer park
The plunge basin behind the trailer park on the left (south) was carved by a waterfall during an early stage of drainage through the east end of Rock Cut Channel. By that time Clark Reservation Channel had been abandoned, its sill having been some 30 feet higher than the top of the south wall of Rock Cut Channel at this location. Drainage therefore spilled into Rock Cut Gorge from the south wall and flowed eastward within the gorge to Butternut Trough.
For this to occur, Rock Cut must have been incised essentially to its present level during an earlier episode of channel cutting. Most, if not all of the drift that had been deposited in the eastern half of Rock Cut Channel during the prior ice advance was flushed out down to the 600-foot level or lower.
Another less well-developed plunge basin was carved as a scallop in the south wall of Rock Cut 700 feet or so farther west, but is not readily seen from the road.

Boulder gravel exposed behind trailers on left.
These gravels include clasts more than 2 feet in diameter and form a gravel spit built across the plunge pools on the south side of Rock Cut. Large scale cross-bedding has a southward component into the plunge basins.
This spit is interpreted as being a product of the limnic hlaup which introduced the late phase of Rock Cut drainage. The top to the spit is 640 feet above sea level, 90 feet above the floor of Rock Cut Channel at this point, thus placing an upper limit of about 90 feet on the depth of water during catastrophic discharge through Rock Cut Channel.

This is the inferred location of the drift barrier
This is the inferred location of the drift barrier which diverted meltwater northward during the active life of Nottingham Channel. Breaching of this barrier released the waters of the lake impounded in Onondaga Trough and produced the catastrophic flood responsible for many of the features we have seen today. The barrier is presumed to have consisted of drift, which must have been thoroughly saturated and may well have been quite permeable. If the drift was permeable, springs discharging on its east flank may well have contributed to erosion and subsequent failure of the dam. The Onondaga Trough Lake stood at 700 feet and extended to the west flank of the drift barrier. The barrier could not have been much more than 2000 feet wide, separating the lake waters from a potential discharge route 100 feet lower.

Leave Rock Cut Channel at its west end, entering Onondaga Trough.

View of Onondaga Trough on right (west).
Note the broadly rounded, u-shaped cross profile, the result of glacial modification of a pre-existing stream valley. The road here would have been under about 20 feet of water at the time that Clark Reservation waterfall was active. With the shift of discharge to the plunge pools along the south side of Rock Cut Channel, this became the temporary shoreline. Activation of Nottingham Channel dropped lake level about 40 feet below the road. Breaching of the drift barrier in Rock Cut Gorge let the lake drop another 100 feet. Each foot of lowering of lake level during removal of the drift barrier meant an additional 15,000 acre-feet of water to escape through Rock Cut and High Bridge Channels.

West end of Smoky Hollow Channel on left (east).
This is the highest, and the first of the several channels to have been activated by post-Valley Heads glacial recession. When the floor of Smoky Hollow controlled the level of Onondaga Trough Lake, the water must have been about 380 feet deep.

Excellent view of Onondaga Trough.
Looking southward, one can see the juncture of Onondaga and Cedarvale Troughs (arms of a y-shaped, glaciated valley system) and Tully Trough (stem of the "y"). Terraces visible along the flanks of Onondaga Trough and across Cedarvale Trough are remnants of deltas which record changing lake level in Onondaga Trough.

Terrace gravels on near (east) side of Onondaga Trough below road.

STOP 6 in REST AREA for overview, resume and final discussion.

Tully (Valley Heads) Moraine.
Crest of the moraine stands at 1200 feet, but the valley floor drops 600 feet within a half mile to the north. South of the moraine crest the outwash plain spreads for many miles toward Cortland, This is the moraine that separates southward drainage from the formerly ponded northward drainage.

Crest of the Tully Moraine. Outwash plain to south ahead.

J: LITTLE FALLS DOLOSTONE (UPPER CAMBRIAN)
H. S. Muskatt
Utica College
The Little Falls Dolostone (Clarke, 1903, p.16) has an estimated thickness of 200 feet in the Middleville area (Kay, 1953, p. 37). The unit nonconformably overlies greenish syenite gneiss of Precambrian age.
In this area the Little Falls is largely a thick-bedded, sandy, medium-grained dolostone that weathers to a tan or buff color. Chert nodules and stringers are not uncommon. Some sandstones and conglomerates are found near the base of the unit. Except for the abundant colonial algae Cryptozoon, in cabbage head form, the unit seems to be barren in this area. Because of this apparent barrenness, the sequence of dolostones in the Middleville area is tentatively considered as "Little Falls",
Interest in the Little Falls by mineralogists goes back a long time. Eaton (1824, p.73) reports on the well-developed quartz crystals present in this unit. In places there are zones with packets (vugs) of authigenic quartz crystals. The crystals are generally small, short prismatic to almost equant in shape, doubly terminated, and water clear. Occasionally larger crystals (3 to 4 inches or more) are present. These larger crystals are rarely clear and usually are full of inclusions or flawed. Often associated with the quartz is a black lustrous carbonaceous mineral known as anthraxolite with a composition near that of coal but with different physical properties (Dunn and Fisher, 1954). For example, it does not ignite. Locally the quartz crystals have been termed "Little Falls Diamonds", "Herkimer Diamonds", or "Middleville Diamonds". There have been numerous occasions when local inhabitants have brought in these well-formed, clear quartz crystals for examination, refusing to believe they are not real diamonds, and in several cases, not allowing one to remove the specimen from their hand.
Other minerals often found in the Little Falls Dolostone include:
Calcite
Dolomite
Pyrite
Marcasite
Galena
Sphalerite
Chalcopyrite (?)
Hematite
Glauconite (?)
The glauconite (?) was first reported by Cushing (1905, p. 27) and appears as light-green to bluish-green thin coatings and spots and generally is concentrated in zones. The writer is presently examining this material petrographically and awaiting a report on its X-ray analysis.

Utica College campus seen to left (N).

Factories of Utica Cutlery and Duxbak (outdoor clothing and equipment).

Mohawk River Valley flood plain

Mohawk River

Escarpment face of the Allegheny Plateau.
For the next few miles as you look to the right (S) across the Mohawk Valley physiographic sub-province you will see the northernmost escarpment face of the Allegheny Plateau.

Hummocky glacial topography along this road, many erratics.

Wave-planed hill top to north
In middle distance to left (N) is a presumed wave-planed hill top formed when this area (West Canada Creek valley) was a lake during the Pleistocene.

Slope drops down to West Canada Creek

STOP 1. Exposure of glacial varves about 10 feet thick
Exposure of glacial varves about 10 feet thick seen in the ditch on the right (E) side of the road. There are an average of about 10 couplets per inch which would therefore suggest that this 10 foot exposure took about 1200 years to accumulate. Other varves, stratigraphically higher, are found across the road.

Higher, abandoned flood plain of W. Canada Creek.
Meander scars seen at base of hills to right (W). Eastern Rock Products Middleville Quarry seen to left (E) across West Canada Creek.

STOP 2 Exposures of Precambrian syenite gneiss.
This is considered to be an inlier.

A right turn onto rte. 28S will take you to the Ace of Diamonds
(A right turn onto rte. 28S will take you to the Ace of Diamonds, a commercial "diamond" hunting ground, about 0.5 miles from the inters.)

STOP 3 Quarry of Eastern Rock Products Inc., Plant No.6 Middleville, N.Y.
The quarry is on the right (E) side of the road, the operating plant is on the left (W) side of the road.
The company is a subsidiary of Koppers Corp. The quarry operation, which began in the winter of 1964, achieved its top production during 1971. About 350,000 tons of rock were processed during that year. Almost all production goes into light and heavy construction use. Some is used for rip-rap and some for "cement" blocks. Upon special order a "filter-media stone" is produced to be used for filtration in sewerage treatment plants. The largest percentage of business is for state projects. The plant does the crushing and screening as well as special mixtures according to specifications.
Because of company regulations the quarry has not been carefully examined by the writer. However, cursory examination on several occasions has shown the Little Falls dolostone (Upper Cambrian) to be barren except for "cabbage-heads" of Cryptozoon found in the talus in the southeastern corner of the quarry. In that same corner the greenish spots and coatings of glauconite (?) have been found. Quartz crystals, pyrite, dolomite, and calcite are relatively common along the northwest face of the quarry. Galena, sphalerite, and chalcopyrite (?) have also been found in this part of the quarry.

NYSGA
NEW YORK STATE GEOLOGICAL ASSOCIATION GUIDEBOOK
S.U.N.Y. BROCKPORT and MONROE COMMUNITY COLLEGE
Guidebook to Field Trips
45th Annual Meeting -September 28-30, 1973
Rochester, N.Y. Area
Co-hosts: State University of New York College at Brockport, Monroe Community College
Edited by: Philip C. Hewitt, Department of, The Earth Sciences, SUNY Brockport
Field Trip Leaders Robert W. Adams, Department of The Earth Sciences, SUNY Brockport William A. Bassett, Department of Geological Sciences, University of Rochester Samuel J. Ciurca, Jr., Eastman Kodak, Rochester, N.Y. Thomas X. Grasso, Department of Geosciences, Monroe Community College Gary L. Kinsland, Department of Geological Sciences, University of Rochester William Kirchgasser, Department of Geological Sciences, SUNY Potsdam Wendell D. Rhodes, Department of Anthropology, SUNY Geneseo Robert A. Sanders, Department of Geosciences, Monroe Community College Victor E. Schmidt, Department of The Earth Sciences, SUNY Brockport Richard A. Young, Department of Geological Sciences, SUNY Geneseo
PREFACE
In preparing this guidebook the basic premises accepted were that simplicity was to be primary and maximum flexibility of style and opinion would be maintained.
Therefore, the editor made no attempt to alter any author's style or opinion. In this way, of course, the editor's task became easier. All that remained was to do the usual proofing, make minor changes and prepare the parts as a whole. Even this task was simple since each field trip is a whole unit and the guidebook merely a collection of field trip descriptions.
If the trips and the meeting are successful it is because of the efforts of many people; the contributors, my patient faculty and students, my secretary and many others including Mrs. Marion Cassie who designed the cover. My thanks go to them and most particularly to Thomas X. Grasso of Monroe Community College who is my co-host.
We hope you will enjoy the trips and the many different styles in this book.
Philip C. Hewitt Editor
The geology of the Rochester area involves some intriguing problems. These are primarily based in the fields of paleontology and stratigraphy, glacial geology and geomorphology, mineralogy and other related subfields. A simple way to describe the geology as a whole is that it involves Lower Paleozoic (Ordovician to Devonian) sedimentary rocks veneered by dissected glacial deposits.
Although a few minor folds appear and the area displays a small number of faults, this is not the easiest place in which to observe structural geologic features. Nor will one find igneous or metamorphic rocks in place here. Rather they can only be seen as erratics from glacial deposition. It is obvious therefore, that the field trips selected for our area involve the type of geology which is so plentiful and well exposed here.
The emphasis for each trip is to teach. The method or style used by the field trip leaders may differ but the intent is the same. In every case the student is the person for whom the trips were planned and for whom the papers were written. The only assumption that is made is that the student has had at least a few courses in geology and will be able to follow the basic concepts involved.
The oldest rocks exposed in this area are of the late Ordovician and are found in the "Rochester Gorge" of the Genesee River Valley. Most of the rocks exposed at the surface in the northern part of the area (south of Lake Ontario) are Silurian in age. Knowing that the strata dip generally to the south it is obvious that younger strata will appear in the southern part of the region. Therefore, Devonian beds are exposed south of Rochester. Erosion by streams and ice and subsequent deposition by glacial action represent the most obvious later events following post-Paleozoic uplift. Yet weathering and erosion continue to leave their mark - erosion by humans shows strongly.
All field trips have been designed to add to the brief outline above. The mineralogic visit to the Penfield Quarry is placed in context with the stratigraphy and general geology of the Rochester area. At Hamlin Beach recent sedimentation will be observed - though no precise details can be given in this guidebook for that locality. Recent water levels and strong wave action have altered the entire picture there. No one can predict what conditions will be like at the time of the trip. We shall have to wait and see.

A: GLACIAL GEOLOGY OF THE WESTERN FINGER LAKES REGION
Victor E. Schmidt
State University College at Brockport
Note: This trip and discussion are designed primarily for undergraduate students, rather than for specialists in glacial geology -- who are, nonetheless, most welcome.
An attempt, however imperfect, is made to distinguish observations from inferences, hypotheses, and speculations based on these and other observations.
The number of proposed stops is probably greater than time will allow, and so selection will be made on the basis of weather conditions and the interests of the group.

A: GLACIAL GEOLOGY OF THE WESTERN FINGER LAKES REGION

Honeoye Creek
At Rush, Rt 15A crosses westward-flowing Honeoye Creek, carrying water from three of the western Finger Lakes to the Genesee River, which flows northward to Lake Ontario.

Glacial drainage channel
At Sibleyville, 1.3 mi from Rush, the route crosses a broad, swampy, flat-bottomed valley, interpreted as a glacial drainage channel which carried a river of glacial meltwater eastward, along the front of the glacier. (If time permits, a slight detour via Phelps Rd and Wagner Rd will allow a better view.)

Middle Devonian Onondaga limestone
Directly west of Honeoye Falls, 3.6 mi from Rush, is an outcrop of Middle Devonian Onondaga limestone, the formation over which Honeoye Creek falls at Honeoye Falls.

Drumlins
Long, streamlined hills - typical drumlins - parallel the route; the road goes over several, and a large one can be seen to the west, from approx 4 mi south of Lima.

Road crosses a field of drumlins, many of them wooded, at about 1200 ft.

STOP 1. Rt 20A between Hemlock and Honeoye
Rt 20A between Hemlock and Honeoye, 2.5 mi east of jct with Rt 15A. (Bus to let group off on left side of road, opposite bedrock exposure; then to wait on left side of road beyond
road cut ahead.)
Bedrock exposure: Shale of the Sonyea Group, Upper Devonian. Note bedding, joints, and concretions. Are there any fossils?
Questions: How resistant is this shale to weathering? How resistant would it have been to glacial abrasion; to glacial plucking?
Road cut: Cut in the south end of a drumlin. An unsorted mixture of rock material, from clay-size to boulders. Much dark gray shale and clay. Many exotic rocks. Many stones show scratches.
Exotic stones: (Possibly groups determine percentages)
Composition -crystallines__: red sandstones__: limestones and dolomites ___: others ___%
Shape - well rounded___: subrounded subangular___: angular___%
With scratches ___%
What is the fabric of this material, if any? (Possible demonstration. )
Inferences: The material is lodgment till which includes much ground-up and broken-up "local" shale. This till was deposited beneath an actively moving glacier. Well rounded, yet scratched, pebbles represent glacially transported and abraded stream bed or lakeshore gravel.
The drumlins were formed by the "plastering" of till on bedrock. Their streamlining is a result of shaping by delicate adjustment of deposition and erosion (re-erosion?) to such conditions as load, velocity, pressure, and temperature of the bottom ice.

Honeoye Lake, delta
Honeoye Lake, one of the smallest Finger Lakes, drains northward into the Genesee River, Deltas show on both sides of the lake; the largest, California Point, on this side, has a trailer "park".
How does the spacing of the cottages appeal to you?

STOP 2. West Lake Rd, 4.6 mi south of Honeoye.
View:
South end of Honeoye Lake. Steep valley sides; no roads descend the slopes here. Small streams in steep gullies marked by dark conifers. One of these streams goes under the road, nearby.
Briggs Gully, a bedrock gorge directly across the lake, descends 700 ft in approx 2 mi. At its lower end is a gently sloping area, underlain by gravel, which extends into the lake.
South of here, Honeoye Valley shows an interesting cross-profile which makes a sharp break with the upland surface on either side. Is this cross-profile a catenary curve? How does one tell?
Compact lodgment till is exposed in the bed of the small gully nearby. Exotic boulders of augen gneiss, anorthosite, etc.
Inferences:
Honeoye Valley was originally a preglacial stream valley, later deepened and steepened as a result of glaciation. It was affected by glacial abrasion, plucking or quarrying, and possibly also by frost wedging beneath the glacier and ahead of it. In addition, there probably was considerable erosion by meltwater. Undoubtedly the valley was subjected to, not a single glaciation, but repeated glaciations - both advances and retreats.
The small streams which flow down the steep slopes are consequent streams. They developed in consequence of a "new" land surface that resulted from glacial erosion of the preglacial valley. Hence these streams are postglacial consequents.
Briggs Gully was formed as a result of a great increase in the erosive ability of the creek in descending from an upland valley, at nearly the preglacial level, to the level of the present lake. It joins a hanging valley, at about 1700 ft., with the glacial trough of Honeoye Valley. Hence the gully is postglacial, or interglacial, or a combination of both. Material excavated from the gully has been, and is being, deposited in a combination alluvial fan and delta at the base. This adjoins the delta at the head of the lake.

Glacial trough and the postglacial consequents
The steep slopes of the glacial trough and the postglacial consequents show well. The rock slides may be due to cutting timber.

Hunt Hollow
At Hunt Hollow note the knobby hills, and the flat-floored, swampy channel, containing ponds, in the valley bottom

STOP 3. West Lake Rd, 12.7 mi south of Honeoye
Road cut and hillside:
Gravel and sorted sand. Many pebbles, especially exotics, are well rounded. Many are scratched, including some that are well rounded. Are there any indications of the direction of water flow?
Knobby hills, with "dimples", similar to the hilly topography in Honeoye Valley between Hunt Hollow and here.
The hilltop affords an overlook of the flat-floored, swampy channel noted previously along the road northwest of here. This channel curves around the far side of the wooded hill ahead (SSW). The topographic map (Naples, 7.5') shows the relationship clearly. Almost the same situation occurs about 0.5 mi to the east.
In the distance are high bedrock hills: Hatch Hill (ESE), above Naples, at 1800+ ft; Knapp Hill (SE) at 2040+ ft; Pine Hill (S) at 2040+ ft; unnamed hill (SSW) above Atlanta, at 2012 ft. Valleys between these hills include: Canandaigua Valley, south end between here and Hatch Hill; Cohocton Valley, north end between Pine Hill and the hill above Atlanta; North Cohocton-Dansville Valley, east end this side of the hill above Atlanta.
At the junction of these valleys is a large area of knobby topography. Much higher and nearer is a flat-topped gravel terrace.
Inferences:
The material in the road cut is morainic. Much of it, at least, was deposited by meltwater, possibly in standing water of an ice margin or preglacial lake. The knobs and "dimples" on the hillside represent a constructional slope of the moraine.
The flat-floored channel is the spillway of a proglacial lake, at 1140+ ft, in the Honeoye Valley. The wooded hill ahead is a "run-around hill"; or umlaufberg -probably a knob of bedrock isolated by the proglacial lake overflow when its former course was blocked on this side by ice or morainic material.

Naples Tree: lycopod or club moss
West of Naples, at the mouth of Grimes Gully, D.D.Luther found the "Naples Tree" in 1882. This is the "trunk" of a lycopod or club moss, 16t ft long, of Upper Devonian age, now on display in the New York State Museum in Albany.

STOP 4. Bristol Springs Road (County Rd 12) 2 mi north-northeast of Naples
Overlook: (at vineyard of Mr. David Gentner)
South end of Canandaigua Lake, with Parish Flat and West River Valley. West River, flowing from the northeast, makes a barbed junction with northward-draining Canandaigua Valley.
Small postglacial consequent streams descend the steep sides of the valleys in small ravines, marked by dark conifers.
Parish, or Conklin, Gully (SE) is a bedrock gorge, with a gravel pit near its base. The gorge ends at a broad, semicircular area of gently and uniformly sloping farmland.
Inferences and comments:
The barbed junction of West River Valley and Canandaigua Valley supports the concept of ancient south-flowing consequent drainage of this region, later reversed as a result of stream capture or the blockage of valleys by glacial deposits. Fairchild inferred that, during Tertiary times, the Canandaigua Valley drained into the west-flowing Dansville River; at the present site of Sonyea this joined the obsequent, north-flowing Genesee River, and then continued northward to the subsequent Ontarian River (1926, p. 224 and Plate 84).
Parish Flat is a modern delta deposited at the head of Canandaigua Lake. The gentle slope at the base of Conklin Gully is on an alluvial fan. The gravel being excavated near the base of Conklin Gully may be part of a delta built by this stream into a proglacial lake that occupied the valley to this height when drainage to the north was blocked by glacial ice. More likely, it is in a kame terrace built between stagnant ice in the valley and the bedrock side of the valley. There is a bench partway up the valley side along Conklin Gully, but its cause is not known. It may be due to resistant bedrock, or possibly is a higher delta or kame terrace.
Note the attempts by man to "improve" Canandaigua Lake and its environs by bulldozing shale from the slope into the lake, allowing more cottages to be built. Fortunately, this endeavor seems to have been stopped by New York State. But others continue!

STOP 5. (Lunch stop) Ontario County Park.
Road from Bristol Springs ascends the west side of Canandaigua Valley. Shale and sandstone of the West Falls Group, Upper Devonian, are exposed, as well as considerable glacial drift.
View eastward:
Appalachian Plateau, dissected by deep valleys. Sub-accordant summit level at approx. 1900-2000 ft.
Highest hill (NNE) is Stid Hill, 2080+ ft. Moderately sharp hill (ENE) is Bare Hill, 1540+ ft, with Canandaigua Valley on this side of it and Vine Valley to the right and beyond it. Like West River Valley, Vine Valley also makes a barbed junction with Canandaigua Valley.
Inferences and question:
The sub-accordant summit level is an erosion surface, considered by Cole to have been reduced below the Upland Peneplain (1938, pp. 194, 196; 1941, p. 148). The main valleys below this surface were deepened by preglacial streams as a result of rejuvenation, and later deepened further by glacial erosion. Is this view valid?
The "Jump-off":
Overlook, at approx 2100 ft, of Berby Hollow, approx 1300-1400 ft at the bottom. This valley contrasts sharply with the upland surface. Its cross-profile approaches a catenary curve.
Berby Hollow contains no major drainage - only small creeks. Divide area is in the middle distance. Hummocky hills of gravel on the valley floor; some of these have been destroyed.
Question and inferences:
How much of the shape of Berby Hollow is due to preglacial rejuvenation and stream incisement, and how much to glacial erosion?
Gravel hills on the valley floor are ablation deposits let down by the last remnants of glacial ice, probably stagnant.
Exotics in the till here include red sandstone of the Grimsby (Medina), and possibly Queenston, formations. These formations outcrop in a belt passing through Rochester and along the south shore of Lake Ontario, below approx 400 ft. The presence of their fragments here indicates that the ice sheet covering the site of Rochester must have reached a thickness of at least 1700 ft, about 4 times as high as the Xerox Tower in Rochester.

STOP 6. Rt 21, 2 mi southwest of Naples.
Road cut and vantage point:
Unsorted mixture of clay-size to cobble-size material. Many exotic rocks. Limestones, especially, show scratches. Calcareous nodules (concretions?) also occur in the material. The stones consist of - crystallines____: red sandstones____:
carbonates____: local gray siltstones and sandstones ____%
Approx____% show scratches.
Hummocky topography, with many hollows, covers a large area between bedrock hills, at the junction of the major valleys.
Three terraces visible in distance: largest, wooded (E of N) at 1100-1120 ft; smallest (N) at 1200 ft; highest (NNW) at 1340 ft;
Inferences and questions:
Material in road cut is till, possibly containing much scraped-up proglacial lake clay. Hummocky topography marks an end moraine, probably correlative with similar moraines at the heads of other Finger Lakes valleys, named the Valley Heads Moraine by Fairchild (1926, p. 226 and Plate 88). This moraine was deposited during a several-hundred-year time of balance between forward movement and the backward melting of the ice, during the last general recession. C-14 dates indicate this may have taken place as recently as 12000 years BP. (What are the most recent data?)
What is the origin of the calcareous nodules? How old are they?
The terraces are possibly high-level deltas deposited in three different levels of proglacial lakes occupying this valley while drainage toward the north was blocked by ice. If so, one or more of them may have been deposited by outflow from a proglacial lake in Honeoye Valley. However, these terraces may instead be kame terraces, deposited between stagnant ice and the valley side, possibly ice-margin deltas built by meltwater streams.

Proceed westward and southwestward across the Valley Heads Moraine
Note morainic topography, including kettles. A flat-bottomed channel runs southwestward along the west side of the valley. Fairchild identifies this as the spillway over the moraine of Lake Naples, a proglacial lake in the south end of the Canandaigua Valley (1895, p. 362), presumably post-Valley Heads in age.

North Cohocton-Dansville Valley
Immediately south of the moraine, the route crosses the North Cohocton-Dansville Valley, floored by gravel, probably outwash.

STOP 7. Black Creek Rd, 0.4 mi S of Sawdust Rd (County Rd 36).
Blackcrick Hollow:
Steep-walled north-south gorge. Flat, swampy floor south of the divide at 1460+ ft. Bedrock exposed in walls. Alluvial fans at the base of tributary streams.
Inferences and questions:
This is a marginal drainage channel or glacial lake spillway (How does one tell the difference?), formed by meltwater erosion of a preglacial valley or col. (How much lowering of the preglacial divide is indicated? Can this be estimated from the map?)
If this channel is the former spillway of a proglacial or ice margin lake, presumably in the North Cohocton-Dansville Valley, at 1460+ ft, what kept the lake from escaping through the southward-draining Cohocton Valley? Possibilities include:
a) Stagnant ice blocking the Cohocton Valley at, or south of, North Cohocton and Atlanta.
b) The end of a lobe of ice, possibly the Canandaigua lobe at North Cohocton, or the Keuka lobe at Bath, blocking the Cohocton Valley during or before Valley Heads time.
c) Valley Heads or "advance" Valley Heads end moraine, or even earlier end moraine (Arkport or Almond?), blocking the Cohocton Valley south of North Cohocton.
Is it just happenstance that a pitted gravel terrace (kame terrace or delta?) on the north side of the North Cohocton-Dansville Valley, nearly opposite Blackcrick Hollow, attains the same elevation (1460+ ft) as the divide in Blackcrick Hollow?

Blackcrick Hollow drainage channel
The Blackcrick Hollow drainage channel or spillway seems to lead toward a series of gravel terraces on the west side of the Cohocton Valley, north, west, and especially south of Cohocton. Some of these attain elevations of 1480+ ft and possibly more.
What is the nature of these terraces? Are they deltas, kame terraces, outwash, or what? Why are there several levels? What caused the concavely curved bank at one level, visible from Loon Lake Rd, Rt 371, just west of Cohocton? Later, if time permits, these features will be seen and discussed.

STOP 8 East side of Rt 371
Terrace and gravel pit: (on property of Mr. Myron Crouch)
Somewhat sorted and stratified "bright" gravel and sand. A great variety of exotic rocks. Pebbles mostly well rounded. Well rounded boulders of resistant crystalline rocks; poorly rounded blocks of local sandstone. Many "ghost" pebbles of weathered carbonates, including cherty Onondaga limestone.
The pebbles consist of --crystallines___: red sandstones___: carbonates___: local gray siltstones and sandstones___%
They are --well rounded___: subrounded subangular___: angular___% The depth of leaching of the gravel is ______ft.
The face of the terrace is fairly straight, but shows some "dimples". A similar terrace, with kettles, occurs on the opposite side of the valley, toward the southwest.
Inferences and questions:
The gravel was deposited by energetic meltwater, close to the ice margin. Could it be, in part, an alluvial fan deposited by Kirkwood Creek up against glacial ice in the valley?
Does the terrace indicate an "advance" Valley Heads position (Muller, 1966), or is it pre-Valley Heads in age? Connally considers it to be the easternmost remnant of Arkport Moraine (1964, p. 43). Just how was it formed? Possibilities include:
a) Deposition by meltwater at the margin of an active ice tongue --an end moraine or lateral moraine, possibly eroded later by meltwater from the Valley Heads ice.
b) Deposition by meltwater between a mass of stagnant ice and the east side of the valley --a typical kame terrace.
c) Deposition of outwash gravel on top of buried stagnant ice in the central portion of the valley; this later melted out, causing the collapse of the gravel in the central portion, but not here at the side (Rich, 1943, p. 98).
d) Deposition of outwash gravel up to the level of the terrace, followed by dissection by a later meltwater stream, leaving the terrace as a remnant of the former high-level outwash deposit.

STOP 9 Rest area on east side of Rt 15
View: Cohocton Valley, an essentially straight, steep-walled, nearly northwest-southeast valley, floored by gravel. The thickness of the gravel, not known, may be obtainable from well logs.
Across the valley is a bench of gravel which attains an elevation of 1480+ ft. It is directly south of Blackcrick Hollow. The face seems to show two levels here; more north of here.
Cohocton Valley is a "through" valley, probably eroded to a large extent by glacial meltwater, as well as by glaciers. According to Fairchild, the preglacial divide was north of Bath (1926, Plate 84). The valley shows truncated spurs, and is floored by a valley train of Valley Heads outwash. Tributary streams have built alluvial fans on top of this outwash.
The gravel bench appears to be a kame terrace, consisting of outwash gravel deposited against stagnant ice. Ice-contact surfaces show especially well on the opposite (southwest) side of the deposit, where it stands free from bedrock. At its southeast end there appears to bean area of collapsed drift.
Is it possible that this gravel bench is, instead, a delta built into a lake in the Cohocton Valley? If so, what held in the lake?
In any case, what caused the two or more levels on the deposit?

Terrace with a concavely curved bank.
Just west of Cohocton, Rt 371 ascends several terraces, one with a concavely curved bank. Could this be the cut bank of a meander, possibly of an outwash stream flowing between ice on the east and the gravel bench on the west?

View ice-contact surfaces

Hinkle Hollow view
Hinkle Hollow Rd at one place is nearly 2100 ft above sea level, affording a good view of the surrounding summit level --inferred by some to be an uplifted peneplain. The till on this hilltop contains relatively few exotics.

Glacial drift
Farther west the road descends into the next north-south valley, containing Loon Lake and much glacial drift in knobs and terraces. Connally identifies this drift as Arkport Moraine (1964, p. 43), which is possibly "advance" Valley Heads Moraine.

North Loon Lake Church kettles
Here, if time permits, a brief stop will be made to view several kettles in a kame terrace. Was each of these formed by a separate block of buried ice, or was there just one large, irregular block? Was
the ice completely or partially buried? How can one tell?

Loon Lake
The road passes Loon Lake, interpreted to be a kettle lake. Note crowding of the lakeshore by cottages. Would it not be better to have the lake and the surrounding area made a park, to be enjoyed by all? This would also reduce pollution of the water and prevent all the interesting gravel deposits from being destroyed!

STOP 10. Rt 21, west of Loon Lake.
Hillside and gravel pit: Irregular, steep gravel slope with hollows and projections. Gravel
is "bright", containing many rounded exotics, somewhat sorted and stratified. A very small percentage of rounded pebbles and cobbles consist of conglomerate containing a variety of pebbles, including crystallines, red sandstones, limestones, and dolomites --all firmly cemented.
The slope is constructional, formed in contact with stagnant ice. The hollows are kettles, and the projections crevasse fillings.
The pebbles and cobbles of exotic-rich conglomerate consist of meltwater-deposited gravel of a previous glaciation cemented during an interglacial time, then eroded during a later glaciation and rounded and deposited by meltwater. Abraded pebbles and boulders of similar conglomerate have been reported from meltwater gravels in several localities in central New York (Schmidt, 1947), and also have been found in till. How much time was required for cementation of this conglomerate to take place? Was an interglacial stage necessary, or would an intraglacial substage have been sufficient? Could it have taken place during minor oscillation of the ice front?

STOP 11. Straight Rd, just west of Price Rd.
Vantage point: Hemlock Lake (left, NNW) and Canadice Lake (right, N). Difference in levels is obvious (905 ft; 1096 ft). These are two of the smallest Finger Lakes, and nearly the farthest west. Both drain northward to the Genesee River.
Sub-accordant summits: hill West of Springwater (WSW) 2060+ ft; Marrowback Hill (NW) 1940+ ft; Bald Hill (N) 1860+ ft. According to Fairchild, Marrowback Hill is capped by Wiscoy shale and Bald Hill by Gardeau sandstone, both Upper Devonian (1928, p. 81).
West of Springwater, a creek descends the valley side in a steep gorge.
The apparent southward confluence of Canadice and Hemlock Valleys suggests former southward drainage, followed by reversal. Did this reversal occur preglacially, as a result of the capture of south-flowing consequent streams by an encroaching north-flowing obsequent stream? Or did it result from glacial deposition in the valleys south of the lakes? VonEngeln implies the latter, and on this basis distinguishes Finger Lakes "West" from Finger Lakes "East" (1961, pp. 27, 38-45). Well logs might throw light on this matter.
The hill summits may represent an uplifted peneplain, although they probably are considerably lower than the former level of this uplifted erosion surface, if there actually is one.
The gorge west of Springwater possibly was eroded chiefly by overflow from a proglacial lake in the south end of the valley of north-flowing South McMillan Creek, on the opposite side of Marrowback Hill. In any case, the gorge is postglacial, interglacial, or both.

Road runs along the delta at the head of Hemlock Lake.

Reynolds Gully
It then passes over a large alluvial fan at the base of Reynolds Gully, a postglacial (or interglacial, or both?) gorge 2 mi north of Springwater.

STOP 12. Rt 15A, 4.6 mi north of Springwater
Overlook:
Hemlock Lake lies in a long, narrow, straight, essentially north-south trough. The depth of the trough, from the top of Marrowback Hill (W) at 1940+ ft to the deepest part of the lake, 809 ft, is 1131+ ft.
Inferences and comments:
The narrowness and straightness of this trough suggest that it was developed from a narrow valley of a relatively small stream. Possibly the trough was preceded by a narrow, steep-walled sluiceway eroded by south-surging meltwater during glacial advance.
Hemlock Lake is a major source of the Rochester area water supply. It is delightfully clear, and makes good canoeing. Note the contrast with Honeoye Lake in regard to the crowding of cottages along the lake shore. Hemlock Lake and Canadice Lake could be the start and nucleus of a Finger Lakes National Park!

B: A COMPARISON OF ENVIRONMENTS
Thomas X. Grasso
Chairman Department of Geosciences
Monroe Community College
The Middle Devonian Hamilton Group in the Genesee Valley
The Devonian System of New York State varies from carbonates at the bottom (Helderbergian and Ulsterian Series) to coarse continental clastics at the top (Chautauquan Series) and represents a westward migrating deltaic complex built during Middle and Late Devonian time, (Rickard, 1964).
This deltaic complex, the Catskill Delta, is today represented by a wedge of sedimentary rock that thickens and coarsens eastward toward the Hudson River. These rocks are highly fossiliferous and structurally simple, thereby, lending themselves to detailed faunal, stratigraphic and paleoecologic studies.
Since the Middle and Upper Devonian of New York represents a deltaic complex, at any instant in time during the Devonian there existed a series of transitional environments aligned approximately parallel to the old shoreline from west to east or offshore deep water to onshore shallow water. These contemporaneous environments are not only transitional with one another laterally, but they also succeed each other vertically since the delta prograded westward across New York State. Each environment is today characterized by its own distinctive rock type and fossil assemblage. For example, the fine shale deposits of the Middle Devonian in the west (Lake Erie) gradually coarsen to siltstones and sandstones eastward (Catskills). The fine shales of the Middle Devonian on Lake Erie are in turn succeeded by the coarser siltstones and sandstones of the Upper Devonian.
The purpose of this field trip will be to sample and contrast several offshore Devonian biotopes representing two major environments; a poorly oxygenated phase of dark shales ("Cleveland" facies), and an oxygenated environment of soft calcareous blue-gray shales and limestones ("Moscow" facies).

B: A COMPARISON OF ENVIRONMENTS

Small ravine on left exposing 11 feet of Onondaga Limestone.

STOP 1. TRIPHAMMER FALLS (Centerfield Mbr.)

STOP 2. Jacox Run
Jaycox Run Section
Centerfield Member
Seven feet of the Centerfield is poorly exposed in the stream bed and small side banks (1-2') just upstream from the old railroad trestle at the base of Jaycox Run. It is mostly a shaly limestone or very calcareous shale at the base of the exposure becoming more shaly and darker upward grading into the Ledyard above. The upper boundary is not a lithologic one but a faunal one being placed at the top of the uppermost abundantly fossiliferous zone (Zone B).
Zone A: The lower part of the exposure is composed almost entirely of microphagous carnivores of bryozoa and corals. Solitary horn corals dominate the assemblage, to the exclusion of almost all other invertebrate species except bryozoans. In this aspect it is almost a coral biostrome and closely parallels those described by Oliver (1951): Heliophyllum halli is very abundant; Amplexiphyllum haniltoniae, Heterophrentis simplex Aulopora sp. are abundant; Favosites alpenensis is common; Favosites hamiltoniae is present. (Descriptive terms for abundance throughout the text from the table on page 11.) The overwhelming domination of microcarnivores certainly means minimal amount of clastic influx with abundant nutrients in shallow, warm, well lighted, agitated waters. Other species are represented by relatively few individuals.
Zone B: Atrypa reticularis Zone: Influx of clastics ended the rugosan-bryozoan domination allowing for the establishment of other feeding groups. Large epifaunal filter feeders dominate this zone especially the brachiopods Atrypa reticularis, (abundant), Mucrospirifer mucrunatus (present) and Megastrophia concava (rare). Vagrant epifaunal forms are conspicuous represented mostly by Platyceras (common) and Phacops rana (present). Corals and bryozoans still survive though reduced in numbers.
Ledyard Member
The Ledyard Member is composed of approximately 57 feet of dark gray calcareous bituminous shale with some black shale interbeds. Calcareous non-septarian concretions mostly small (less than 1 foot in diameter) are abundant at certain intervals throughout the unit. Larger septarian concretions are found toward the top of the Ledyard.
Zone C: Ambocoelia-Chonetes zone: Gradually deteriorating conditions for epifaunal filter, microcarnivore, and infaunal filter feeders beginning during later Centerfield time culminated in their complete removal by Ledyard time. Soft muds high in organic matter allowed infaunal deposit feeders (worm tubes common) and vagrant epifaunal deposit feeders (Phacops rana-common) to flourish initially along with the small filter feeding Ambocoelia (common) and Chonetes (common). Perhaps this interval should be set off as a subzone based on the abundance of Phacops rana. Many of the trilobites are complete, a few are enrolled. They are found nearly parallel with the horizontal, dorsal surface up and some reversed with the ventral surface up. This means that Phacops and to a lesser extent Greenops moved on the substrate plowing or occasionally burrowing into it for food. The fine, bituminous,dark shales in which they are found were soft muds high in organic matter an indication perhaps that Phacops was a deposit feeder.
Zone D: Leiorhynchus Zone: Although this interval is nearly covered, some patches of it are exposed for sampling purposes. It is mostly a calcareous, bituminous, black shale with some dark shale interbedded with it. For all intents and purposes the only species found is Leiorhynchus guadricostatum (very abundant). Anaerobic conditions at or above the sediment-water interface existed during the time of deposition of Zone D.
Zone E: (Second Ambocoelia-Chonetes Zone) and Zone F (Phacops rana Zone) are recurrences of Zone C conditions. One unusual addition is a small thin zone at about 75 feet containing the gastropods: Moulonia itys (present), Nauticonemalineata (present), Loxonema hamiltoniae (rare), and Bembexia sulcomarginata (rare), the cephalopod Orthoceras (common), and the infaunal deposit feeding clams Nucula (rare), Paleoneilo (present), and Nuculites triquetor (rare). This deposit feeding assemblage indicates high organic matter in the substrate and oxygen levels high enough to support a diverse molluscan assemblage although composed of mostly small individuals.
Wanakah Member
The Wanakah member is composed of 34 feet of dark gray, bituminous, calcareous shale, succeeded by 1 foot of coarse, silty shale and 11 feet of gray, non-bituminous shale, totaling nearly 46 feet in all.
Zone G: Pleurodictyum americanum Zone: Although no lithologic break separates the Wanakah from the Ledyard Shales, the first appearance of Pleurodictyum americanum is generally taken to represent the lower boundary of the Wanakah (Cooper, 1930). Zone G is a highly fossiliferous zone containing species representative of all feeding groups described. Infaunal deposit feeders are only weakly represented. Well oxygenated conditions must have existed although the bottom sediment was fairly soft. Large epifaunal filter feeders are represented by several forms; Mucrospirifer mucronatus (common); Pterinopecten (very rare); Spinocyrtia granulosa (very rare) being a few.
Stereolasma rectum, the solitary small horn coral is common, apparently the larvae attaching to the shells of other invertebrates (Bray, 1971). Pleurodictyum is present, its larvae attaching to the shells of Loxonema. Aulopora is abundant in a thin layer toward the top of this zone. Small epifaunal filter feeders dominate the assemblage. This assemblage is one adapted to a soft bottom environment; the coelenterates found being those tolerant of turbid water and using the shell of other invertebrates as their "firm substrate" for larval attachment.
Zone H: Modiomorpha subalata Zone: Contained with a thin, coarse, silty, shale bed, capping a small waterfall at 82 feet is the first appearance of abundant infaunal filter feeders. A firmer substrate and increased current activity are probably responsible. The endobyssate bivalve Modiomorpha subalata is common, along with the vagrant gastropod Bellerophon (abundant) and the infaunal bivalve Paleoneilo is common. The silty substrate must have been rich in organic matter to support the infaunal deposit feeders.
Zone I: Mucrospirifer mucronatus Zone: Large numbers of the large epifaunal filter feeder Mucrospirifer mucronatus characterize the succeeding 10 feet of dark bituminous shale on top of the Modiomorpha Zone, Ambocoelia umbonata is common in this interval also. Mucrospirifer mucronatus is characterized by the hinge line extending laterally to form large spines or alae. These presumably functioned like skies to better distribute the weight on a soft substratum. The conspicuous absence of Mucrospirifer from other soft bottom horizons (C, E, & F) leads me to the conclusion that C, E, and F were zones of lower oxygen potentials or less particulate organic matter in suspension and available for food. One other possible explanation is the selective predation of Mucrospirifer larvae during or just before spat fall. This explanation seems to be fairly weak as searching through my mind I cannot conceive of an organism responsible for the selective destruction of just Mucrospirifer larvae.
Zone J: (Second Leiorhynchus Zone): This is a recurrence of Zone D.
Zone K: Third Ambocoelia-Chonetes Zone: This is a recurrence of zones C and E. The Ambocoelia, at least in this zone, seem to occur in clusters. Bray (1969) has dealt with cluster development in Ambocoelia of the Ludlowville Formation in Erie County. They apparently initiate as a small patch on an otherwise lethal substrate due to their adaptability on soft substrates. Successive generations use the shells of earlier ones to attach the pedicle, thereby increasing the diameter of the cluster. As density increased fecal matter and other toxic substances could have built up to a point inhibiting further spot development and the cluster became extinguished. Other adjacent "immature" clusters would still survive.
Zone L: Stereolasma Zone: The Stereolasma zone represents a trend to more opulent conditions of oxygen, and food supply in the water and substrate. Microcarnivores are represented by Stereolasma rectum (common) vagrants by Phacops rana (abundant) large epifaunal filter feeders by the brachiopods, Athyris spiriferoides (common) Mucrospirifer mucronatus (common).
Zone M: Styliolina fissurella Zone: Bedding planes containing very abundant individuals of the pteropod Styliolina fissurella can be found above Zone L. They appear to represent catastrophic swarm kills with their shells current oriented in a NE-SW direction. Ambocoelia umbonata is abundant in other layers in this zone. A stressed environment of low oxygen, the Styliolina zone contrasts markedly with the well aerated waters of the Stereolasma Zone.
Zone N: Nauticonema lineata Zone: This zone represents a recurrence of the gastropod faunal in Zone F. Infaunal filter feeders are most pronounced being represented by Taonurus (present). Infaunal deposit feeding is suggested by the numerous limonite stained worm tubes or trails.
Zone O: Second Mucrospirifer mucronatus Zone: This is a reoccurrence of Zone I.
Zone P: Cypricardella-Pseudaviculopecten Zone: At the top of the largest falls in Jaycox Run at 110 feet occurs a foot interval of coarse calcareous silty shale or siltstone. It is characterized by large epibyssate bivalves, endobyssate bivalves, infaunal deposit bivalves, gastropods and brachiopods. This unit presents the highest energy environment of clastic deposition in the Ludlowville Formation of Jaycox Run. Organic material was abundant in suspension, and in the firm substrate. Epibyssates are represented by:
Pseudaviculopecten princeps, (present)
Pterinopecten (rare)
Cyriopecten (rare)
Gosselettia (rare)
Mytilarca (rare)
Endobyssates by:
Cypricardella bellistriata (common)
Actinoptcria decussata -(present)
Leiorpteria conradii (rare)
Modiomorpha mytiloides (rare)
Modiomorpha concentrica (present)
Actinodesma erectum (rare)
Goniphara hamiltoniae (very rare)
Gastropods by:
Moulonia itys (present)
M. lucina (large) (rare)
Nauticonema lineata (rare)
Brachiopods by:
Stropheodonta demissa (present)
Mucrospirifer mucronatus (common)
Mediospirifer audaculus (common)
Infaunal deposit feeders by:
Paleoneilo (common)
Zone Q: Hamilton Fauna: The uppermost 11 feet of the Wanakah member are the most fossiliferous in terms of numbers of species. All feeding types are represented and many species are common to very abundant. A faunal list would be exhaustive; suffice it to say that every common Hamilton form is represented in these 11 feet. This interval represents opulent conditions of temperature, food, substrate, and oxygen. The fossiliferous horizons are separated by a few inches of less fossiliferous shales indicating successive periods of greater deposition separated by the fossiliferous horizons of little or no deposition.
Tichenor Member
Zone R: Tichenor Fauna: The Tichenor Member, a 1 to 2 foot thick hard limestone represents a recurrence of Zone A of the Centerfield Members.
Deep Run Member
Zone S: Crinoidal-Phacops Zone: Zone S encompasses the entire 7 or 8 feet of the blue gray limey shales of the Deep Run Member. Large epifaunal filter feeders represented mostly by crinoids stems and microphagous carnivores by bryozoans are abundant, some endobyssate types are present, epibyssates being rare. Phacops rana is common but extraordinary in size. Some specimens are two to three times the normal size. This fact together with the abundant worm tubes (limonite tubes) suggest abundant organic matter on and in the substrate.
The absence of abundant corals would indicate an environment too turbid for them to become established.
Moscow Formation
Menteth Member
Zone T: Crinoidal Zone: Zone T contains most large crinoid stems. Other feeding tubes are only slightly represented, Phacops rana being the most common vagrant and Taonurus, (common) the infaunal filter feeder.
The assemblage suggests a very turbid high energy environment well suited for filter feeders

Boyd Parker Monument on left.
Site of the murder of Lieutenant Boyd and Captain Parker, two members of General Sullivan's campaign of 1779 against the Iroquois Confederacy to end their continual harassment of colonial frontier settlements in New York. The victims' execution was prefaced by the most insidious torture apparently at the direction of the infamous Mohawk Valley Tory, Colonel Walter Butler.

Genesee Valley Canal
Cross line of the old Genesee Valley Canal which connected Olean with the Erie Canal at Rochester. The Genesee Valley Canal was completed in 1856 and abandoned in 1878. Proceed on U.S. 20A, N.Y. 39.

STOP 3. LITTLE BEARDS CREEK
The Kashong Shale is exposed at this locality and it carries an excellent "Moscow" facies fauna.

STOP 4. TAUNTON GULLY
The upper 20 feet or so of the Windom Member is exposed at the base of the exposure. Upstream from this point there is nearly a continuous exposure from the Leicester Pyrite to the Genundewa Limestone which caps a waterfall at an elevation of about 850 feet.

C: LOWER UPPER DEVONIAN STRATIGRAPHY FROM THE BATAVIA-WARSAW MERIDIAN TO THE GENESEE VALLEY: GONIATITE SEQUENCE AND CORRELATIONS
William Kirchgasser
Department of Geological -Sciences
Previous Work-
The starting point for stratigraphic studies of the Lower Upper Devonian rocks of Western New York is James Hall's (1843) Survey of the Fourth Geological District. In this classic report the names Genesee Slate, Portage Group (with Cashaqua Shale, Gardeau Shales and Flagstones, and Portage Sandstones) became firmly established for the undisturbed and remarkably well exposed sections in and around the Genesee Valley. This far off-shore (basin) succession begins with black and dark gray shales which pass upward into alternating gray, green and black shales, silty gray shales and siltstones, the latter becoming predominant toward the top.
Although little remains of Hall's original subdivision his preliminary observations provided the framework for later detailed stratigraphic studies and the monographs of the rich faunas which these rocks contain (Hall, 1879; Clarke, 1898, 1904). Among the various elements of the chiefly pelagic and molluscan "Naples Fauna" the goniatite cephalopods have received the most attention. Although they lack the diversity of their Eurasian contemporaries, the goniatite faunas from New York have special value because their stratigraphic position and sequence can be rather precisely determined. The correlation of the New York succession with the European standard, by means of goniatites and conodonts, is now generally established (Fig. 1) although a few discrepancies and details still need to be worked out.

C: LOWER UPPER DEVONIAN STRATIGRAPHY FROM THE BATAVIA-WARSAW MERIDIAN TO THE GENESEE VALLEY: GONIATITE SEQUENCE AND CORRELATIONS

STOP 1: BETHANY CENTER, N. Y.
Park below the overpass at right turnoff to Bethany Center.
Walk down hill on north side of Rt. 20 and observe loose blocks of Genundewa Limestone on the embankment. Although the rocks are weathered and picked over, this remains one of the best collecting sites for the fauna of the Genundewa Limestone. In addition to the ubiquitous Styliolina, the more common fossils are species of pterochaenia and Bactrites, Tornoceras (T.) uniangulare compressum and forms referable to Manticoceras styliophilum. The less weathered blocks of limestone yield abundant conodonts when digested in dilute acetic acid.

STOP 2: LINDEN, N.Y.
Walk to edge of Little Tonawanda Creek and observe section of lower Genesee Formation (Geneseo, Penn Yan and Genundewa members) in falls of side creek (Fig. 4A-B) (Private Property).
The contact with the underlying Moscow Formation is at about creek level. At this locality the Geneseo-Penn Yan interval is 31 feet thick; at Eighteenmile Creek near Lake Erie this same interval is less than 0.5 feet thick and on the east side of the Genesee Valley (Stop 7) it is 80 feet thick.
The Geneseo-Penn Yan contact is drawn at the top of a pair of black shales Which outcrop in the face of the falls; the horizon of these shales has been traced westward to Cayuga Creek and eastward to the east side of the Genesee Valley. Manticoceras first appears in the Penn Yan Member in a concretion horizon 8.5 feet below the base of the Genundewa Limestone, which caps the falls. Tornoceras (T.) uniangulare compressum and forms referable to Manticoceras styliophilum are common in the Genundewa Limestone in this area.

STOP 3: WYOMING GULF.
Park on right (S) side of road at jct. with Wass Road (on right).
Contact between Cashaqua and Rhinestreet Shales occurs in road cut above the intersection.
The dark shale facies of the upper Cashaqua is rather poorly exposed here but the characteristic fossil Pterochaenia cashaquae is common at some levels; The horizon of baritic septaria which characterizes the uppermost Cashaqua is not exposed at this locality. A 3 inch thick black shale about 10 feet below the base of the Rhinestreet has been traced in about the same position from Lake Erie to Honeoye Lake.
Walk down the hill and observe roadcuts (or stream section) of the concretion facies of the Cashaqua. The following fossils are common in olive green shales and concretions: Styliolina fissurella, Buchiola retrostriata, Paracardium doris, pterochaenia sp., Protospirialis minutissima, Bactrites aciculum and Probeloceras lutheri. Less common are: Ontaria suborbicularis, Loxonema noe, Palaeotrochus praecursor, Spathiocaris emersoni (crustacean), Tornoceras (T.) uniangulare obesum and Manticoceras sinuosum.
In general the fauna is dominated by small shells and is less diverse than the Naples Fauna in the nodule facies of the Cashaqua around Canandaigua and Keuka Lakes where in more arenaceous, current-reworked, and probably shallower water sediments, the larger bivalves such as Lunulicardium, Ontaria, and Honeoyea were important elements.

STOP 4. STONY CREEK.
Park beyond RR tracks opposite RR station. Cross Rt. 20A (CAUTION) and walk 0.5 miles SOUTH along RR tracks to Stony Creek. Climb down embankment to left of bridge.
CAUTION: STAY OVER TO LEFT, AWAY FROM THE FALLS!!
Observe section in middle part of West Falls Formation (Figs. 2, 5). At this meridian, the western Angola shale facies (member) interfingers with the more arenaceous Gardeau facies. The succession consists of silty gray shales interbedded with siltstones black shales and concretion horizons. The siltstones, many of which are crossbedded and ripple marked, are thicker and more numerous toward the top of the section.
The black shale above the Scraggy Bed, which marks the Rhinestreet-Angola contact around Lake Erie, is represented in this section by a 3 foot 9 inch bed of black shale, 22 feet below the top of the 1 foot thick siltstone capping the main falls. The Gibson's Glen Goniatite Bed (Stop 5) occurs lower down, 25 feet below the base of the Scraggy Bed black shale, in rocks equivalent to the Upper Rhinestreet of westernmost New York. The Point Breeze Goniatite Bed, which has been traced from its type exposure on Lake Erie shore, occurs 7.5 feet above the 1 foot thick siltstone in rocks equivalent to the Lower Angola Shale to the west.

STOP 5 RELYEA CREEK.
Section commences at edge of farm field, 500 yards west of Rt. 19 at c. 1100 feet altitude. (Private property).
Description The Gibson's Glen Goniatite Bed, noted for its well preserved specimens of Manticoceras rhynchostoma, outcrops in the face of the low falls about 100 yards upstream from start of section (Fig. 5); goniatites are also common in concretions about 5 feet above the top of the falls. The Scraggy Bed black shale outcrops about 100 yards farther upstream, about 2 feet above the base of the high falls. The Point Breeze Goniatite Bed occurs in the face of the falls, about 23 feet higher, beneath an 11 inch thick siltstone.

STOP 6. TAUNTON GULLY.
Park on right side of Rt. 36 and cross the highway (CAUTION). The bus will proceed to rendezvous point at top of section. Those who do not wish to walk the entire creek section (about one mile) may stay on the bus:
Section commences in Geneseo shale member (Genesee Formation) above Leicester Pyrite, about 2000 feet west of RR bridge at 730 feet elevation (Fig. 4B).
Styliolina fissurella and pterochaenia fragilis occur in the gray shales and thin argillaceous limestones above the basal black shales of the Geneseo and poorly preserved Ponticeras perlatum and Tornoceras sp. are not uncommon in the most prominent limestone outcropping 17 feet above the base of the member. This limestone is also recognized at White Creek, Beards Creek, and Fall Brook.
The Geneseo-Penn Yan contact is drawn at the top of a pair of black shales about 4.5 feet above the 10 inch black shale near the level of the pool at the base of the main falls. The bed of small nodules immediately below the lower member of the pair of black shales contains rare Ponticeras in the Beards Creek and Fall Brook sections. Forms referable to Ponticeras perlatum occur in the concretion horizon 3 feet below the 1 foot interval of thin styliolina limestones which form the lip of the falls; similar limestones are frequent higher in the Penn Yan member.
Manticoceras first appears in the section in a 2 foot interval of concretions and nodules beneath a 5 inch black shale, 16 feet below the base of the Genundewa limestone member. Probeloceras genundewa occurs in the topmost beds of the Genundewa which outcrop a few feet upstream from the road bridge.

Bridge over Taunton Gully; rendezvous point.

STOP 7 -DEWEY HILL
Roadcut exposes upper Penn Yan shale and Genundewa limestones members (Genesee Formation) (Fig. 4B)
The Geneseo and Penn Yan members are well exposed in the classic section in nearby Fall Brook but most of the Penn Yan is inaccessible except in the side creek. In the road section the Penn Yan is characterized by silty gray shales interbedded with many thin argillaceous limestones and a few concretion horizons. Several of the thin limestones are composed almost entirely of Styliolina fissurella.
Poorly preserved goniatites identified as Manticoceras and Tornoceras occur in a 4.5 inch thick limestone above the interval of concretions near the base of the section, and similar forms occur about 3 feet higher in the lowest member of a set of three Styliolina limestones.
The Genundewa limestone, which caps the Falls at Fall Brook, outcrops at the crest of the hill.

D: EURYPTERID HORIZONS AND THE STRATIGRAPHY OF THE UPPER SILURIAN AND ?LOWER DEVONIAN OF WESTERN NY
Samuel J. Ciurca, Jr.
Rochester, New York
The Upper Silurian rocks of New York State comprise an interesting variety of distinct lithologies, e.g. red and green shales, some sandstone, limestone and dolostone, halite, gypsum, and anhydrite. While these rocks are of economic importance because of the halite and gypsum deposits they contain, much of current geologic interest in these strata is concerned with their sedimentology, correlation, and more recently, the paleontology of certain well-known fossiliferous units (see, for example, Treesch 1972, Rickard 1969, Berry and Boucot 1970, Berdan 1972). Often overlooked is the unusual eurypterid and scorpion faunas which these generally "unfossiliferous" rocks contain.
The purpose of this article and associated field trip is to familiarize the reader with the Upper Silurian and ?Lower Devonian rocks of the Genesee region, particularly the Bertie Group, and to examine outcrops of these rocks at localities which have yielded eurypterid remains.

D: EURYPTERID HORIZONS AND THE STRATIGRAPHY OF THE UPPER SILURIAN AND ?LOWER DEVONIAN OF WESTERN NY

STOP 1. Oaks Corners Quarry

STOP 5. Mud Creek

STOP 6. Bridge over Honeoye Creek

STOP 7. Sewage Treatment Plant

Rock fences primarily of Cobleskill Fm. some stromatoporoids, rare favosites coral

STOP 8. Neid Road Quarry
Town of Le Roy Metal Refuse Disposal

Quarry in the Onondaga Fm.
Entrance to General Crushed Stone Co.-Le Roy plant.

STOP 9. Brief stop
Steam shovel used from 1906-1949 - also small locomotive and car for carrying stone.

Quarries in the Onondaga Fm. on both sides of the road

STOP 10. LAST STOP

E: LATE GLACIAL AND POSTGLACIAL GEOLOGY OF THE GENESEE VALLEY IN LIVINGSTON COUNTY, NEW YORK: A Preliminary Report
RICHARD A. YOUNG
Department of Geological Sciences
SUNY, Geneseo, N.Y.
WENDELL D. RHODES
Department of Anthropology
Geologic and archaeologic investigations in the Genesee Valley have produced evidence of glacial drift blockage (moraine?) within the valley, followed by floodplain aggradation up to 95 feet above the modern river bed. The terraces may have been formed between 2500 and 4400 years ago between Avon and Mt. Morris, New York. The exact manner of emplacement of the abnormally thick till section in the valley is unclear, but the resulting postglacial fluvial aggradation and subsequent terracing appear to correlate in a general way with the periods of neoglacial climatic fluctuation discussed by Denton and Porter (1970).

E: LATE GLACIAL AND POSTGLACIAL GEOLOGY OF THE GENESEE VALLEY IN LIVINGSTON COUNTY, NEW YORK: A Preliminary Report

STOP 1. Cross ice marginal drainage channel

Turn west on Cheese Factory Road following ice marginal channels

Cross Honeoye Creek
Cross Honeoye Creek on approach to Sibleyville, Honeoye Creek occupies ice marginal drainage at this point.

STOP 2. View esker, kettles, and kames at Round Pond

STOP 3. Warren Shoreline
Oak Opening Road follows Warren Shoreline north-south across Routes 5 & 20

STOP 4. Beach along wave eroded drumlin(?) on south side of highway

STOP 5. Gravel pit on west bank near large glacial drainage
Gravel pit on west bank near large glacial drainage which discharged SE into Genesee Valley. View drainage features and gravels mapped as deltas by Fairchild (1909).

STOP 6. For 1/2 mile cross remnant of delta-like deposits
For 1/2 mile cross remnant of delta-like deposits at 580 feet at Conesus Outlet stream which might have been deposited into lake waters prior to the formation of Lake Scottsville at 540 feet. Alternatively it could represent the remnant of a higher floodplain in the Genesee Valley 40 feet above the modern floodplain (See discussion regarding Genesee Valley terraces)

STOP 7. Bridge over river near Fowlerville: view valley profile and till outcrop

STOP 8. Avon landslide of April, 1973
2012: Best GE image from 3/23/2010

STOP 9. Lunch at Dept of Geol Sciences, Geneseo.
View maps, aerial photographs, etc.

STOP 10. Archaeology site in Genesee River terraces
Turn west toward river through field to Archaeology site in Genesee River terraces near confluence with Canaseraga Creek.

F: THE PINNACLE HILLS AND THE MENDON KAME AREA: CONTRASTING MORAINAL DEPOSITS
Robert A. Sanders
Department of Geosciences
The Pinnacle Hills, fortunately, were voluminously described with many excellent photographs by Fairchild, (1923). In 1973 the Range still stands as a conspicuous east-west ridge extending from the town of Brighton, at about Hillside Avenue, four miles to the Genesee River at the University of Rochester campus, referred to as Oak Hill. But, for over thirty years the Range was butchered for sand and gravel, which was both a crime and blessing from the geological point of view (plates I-VI). First, it destroyed the original land form shapes which were subsequently covered with man-made structures drawing the shade on its original beauty. Secondly, it allowed study of its structure by a man with a brilliantly analytical mind, Herman L. Fairchild. It is an excellent example of morainal deposition at an ice front in a state of dynamic equilibrium, except for minor fluctuations.
The Mendon Kame area on the other hand, represents the result of a block of stagnant ice, probably detached and draped over drumlins and drumlinoidal hills, melting away with tunnels, crevasses, and perforation deposits spilling or squirting their included debris over a more or less square area leaving topographically high kames and esker segments with many kettles and a large central area of impounded drainage. There appears to be several wave-cut levels at around the + 700 1 Lake Dana level, (Fairchild, 1923).
The author in no way pretends to be a Pleistocene expert, but an attempt is made to give a few possible interpretations of the many diverse forms found in the Mendon Kames area. Fairchild's work (1923) on the Pinnacle Range seems to need little in the way of additional interpretation.

F: THE PINNACLE HILLS AND THE MENDON KAME AREA: CONTRASTING MORAINAL DEPOSITS

Eggs-in-a-basket kames.

More non-ice-contact kames.

Driving along sub-lacustrine outwash slope.

Cross Clinton Avenue South pit on left.

Kame appears to be ice-contact on north outwash slope.

Circle Reservoir
Circle Reservoir overlooking Rochester till plain to north and Lake Dana basin to south (if clear, may see Bristol Hill-south shore of Lake Dana) Pinnacle Hill high point to west with T.V. towers.

Climbing up Salina Group.

Notice swell and swale topography-both sides.

Notice Drumlins on both sides of road.

Notice collection of erratics on house below on right.

STOP 1. Clover Sand & Gravel Co.
Large cut in esker cone showing torrential bedding.

STOP 2. Get out of bus for walk on esker.

Get back on bus at Devil's Bathtub parking lot

STOP 3. Eggs in a basket, etc.
Look at eggs-in-a-basket kames (non-ice-contact) and edge of kettle with sharp break in slope-(ice-contact).

STOP 4. Entrance to Shafer's Pit
Entrance to Shafer's Pit in large-till-capped? kame, probably draped over drumlin.

STOP 5. Walk on esker segment in east side of park.

STOP 6. View of dissected ice-contact kames.

STOP 7. Optional. Right turn in Russo's pit.
Look at catastrophic bedding overlying pre-glacial Genesee River (?), truncated by ice-marginal drainage channel of Lake Warren II, get on bus for trip back to motel.

G: PLEISTOCENE AND HOLOCENE SEDIMENTS AT HAMLIN BEACH STATE PARK, NY
Robert W. Adams
State University College at Brockport
Erosion and sedimentation along the Lake Ontario shore at Hamlin Beach State Park, ten miles north of Brockport, New York, have exposed and produced numerous sedimentological features. The purpose of this trip is to examine Pleistocene and Holocene deposits in order to observe the variety of materials and structures present and to discuss their possible origins. The high water level condition of Lake Ontario and periodic lake storms have created new exposures of Pleistocene deposits and have removed or made inaccessible other exposures. This situation is not expected to change prior to the field trip and therefore specific localities cannot be designated in this summary. The general types of material which we may reasonably expect to examine are outlined below. It is hoped that the experience of the participants and discussions on the "outcrop" will aid in the interpretation of the Pleistocene features.

Hamlin Beach State Park

H: MINERAL COLLECTING AT PENFIELD QUARRY
William A. Bassett
Gary L. Kinsland
University of Rochester, Rochester, N.Y.
Penfield Quarry, Penfield, N.Y., is in the dense gray Lockport Dolomite and is operated by Dolomite Products as a source of material for road construction. A large variety of nicely crystallized minerals occur in solution vugs as well as cavities associated with corals in the upper portions of the formation. Some of the finest specimens to come from this locality are variously colored fluorite cubes, very clear gypsum, reddish brown sphalerite crystals, celestite crystals, and vugs lined with dolomite and calcite crystals. The origin of these minerals is a subject that can lead to lively discussions.

STOP 1. Penfield Quarry
Lockport Dolomite
The Lockport Dolomite is a hard, dense, fine grained dolomitic limestone of Middle Silurian age. It is quarried and crushed by the Dolomite Products Company for use in road construction. Its resistance to erosion has led to the formation of an escarpment that is a rather prominent feature running west from Rochester to Niagara Falls where it forms the crest of the falls. From there it runs west through Ontario and Michigan. In places it is argillaceous. It is also very petroliferous and has a strong odor of crude oil when broken. Black encrustations and blobs of natural asphaltum are abundant. At Rochester the Lockport Dolomite has a total thickness of approximately 180 feet. Fossil corals are commonly found in some layers but are not easily removed from their matrix. Solution has produced cavities and stylolites which in turn have served as hosts for much of the mineralization.
Mineralization
In spite of numerous outcrops and extensive quarrying of the Lockport Dolomite, there are only certain localities that offer the variety of minerals and well developed crystals found at the Penfield Quarry. The best known of these are the Royalton Stone Quarry east of Gasport on route 31, Frontier Quarry southwest of Lockport, the piles of rubble taken from the Barge Canal excavation at the east edge of the Monroe County Airport and just west of Lockport, and the Walworth Quarry east of Rochester. The minerals described below occur as crystals and encrustations lining the inner surfaces of the solution vugs, fissures, and corals found in the Lockport Dolomite. One reason that the mineral specimens from these localities have been very popular among collectors is the fact that they have formed as crystals growing rather freely into solutions that filled these spaces. The sequence of crystallization among the minerals has resulted in particularly interesting relationships. For instance, calcite crystals are commonly found on top of the dolomite crystals whereas dolomite crystals are commonly found embedded in clear gypsum. The availability and quality of the minerals at the Penfield Quarry vary considerably with time as the quarry workings traverse certain zones.
Anhydrite CaSO4 Orthorhombic mmm
Light blue masses often found completely filling vugs and enveloping other minerals, commonly mixed with fine grained white gypsum. These masses are often found to be somewhat foliated. The gypsum may be an alteration of the anhydrite.
Aragonite CaCO3 Orthorhombic mmm
Sometimes found as white crusts.
Barite BaSO4 Orthorhombic mmm
Distinguished from the more common celestite with certainty only by flame tests or X-ray diffraction. It has an occurrence similar to that of celestite.
Calcite CaCO3 Trigonal bar 3 2/m
Scalenohedral crystals (dog tooth) are sometimes found as large as 15 centimeters; more commonly 2-5 centimeters. Also occurs as beautiful micro-crystals of rhombohedral habit and unusual clarity associated with marcasite on the dolomite. Scalenohedral crystals commonly occur on the dolomite oriented in such a way as to permit firmly attached doubly terminated specimens. Best large specimens are found in dolomite-lined vugs with little else present.
Celestite SrSO4 Orthorhombic mmm
Light blue to white to colorless, translucent to transparent, elongate crystals. A light blue color is fairly indicative of celestite. The colorless crystals may be barite. Often found enveloped by gypsum; beautiful specimens with celestite penetrating transparent gypsum can be found. Crystal size from millimeters to approximately 0.3 meters.
Dolomite CaMg(CO3)2 Trigonal bar 3
Nice translucent white rhombohedral crystals with curved faces lining cavities are a certain find for anyone visiting Penfield Quarry. Crystals are commonly 0.5 -1 centimeter in size and situated so as to show faces. Smaller colorless transparent rhombohedrons may also be observed with a lens and distinguished from calcite by acid.
Fluorite CaF2 Isometric m3m
The most prized specimens from Penfield Quarry are those with free-standing fluorite cubes. They range in size from less than a millimeter to approximately 10 centimeters on a side, though most are in the 1-2 centimeter range. Color ranges from colorless to yellow to green to blue to purple making these especially attractive specimens. Many of the examples exhibit especially fine banding which can be seen in three dimensions within the crystals. The best crystals are found free-standing in vugs lined with white dolomite crystals which make the fluorite colors stand out vividly.
Galena PbS Isometric m3m
Rare. Occurs imbedded in the gray dolomite rock, more rarely as free standing cubes in cavities.
Gypsum CaSO4•2H2O Monoclinic 2/m
Occurs as fine grained white masses as well as the selenite variety of unusual clarity. Some selenite masses are as large as 0.3 meter in length. Occasionally crystal faces can be found. Selenite commonly envelops other crystals, notably celestite and dolomite producing quite nice specimens. Both varieties of gypsum commonly fill entire cavities.
Marcasite FeS Orthorhombic mmm
Small cockscomb masses and singly or doubly terminated crystals usually less than 3 millimeters in length. Most are tarnished to a brilliant iridescent blue; some are pale bronze-yellow. Usually found on dolomite crystals and sometimes imbedded in gypsum.
Pyrite FeS2 Isometric 2/m bar 3
Small cubes and pyritohedrons less than 2 millimeters. Other forms may be present as well. Usually brass-yellow, sometimes tarnished iridescent blue. Usually found on dolomite crystals with little else near except marcasite and colorless rhombs of calcite.
Quartz SiO2 Trigonal 32
Skeletal masses of drusy micro-crystals. Distinguishable in hand specimens from similar masses of dolomite by sparkle and from similar masses of calcite by acid test. Hardness is not applicable because the individual crystals are of the order of tenths of a millimeter. With a hand lens and a careful eye, identification based on crystal forms is possible in some cases. All three minerals may occur together.
Sphalerite (ZnFe)S Isometric bar 4 3m
Variable in color from light yellow to red to dark brown depending on iron content. Occurs as veinlets in the dolomite rock and as curved, thick, fan-shaped crystals that are free-standing in the vugs. The crystals are often a centimeter or more across.
Strontianite SrCO3 Orthorhombic mmm
Sometimes found associated with celestite.
Sulphur S Orthorhombic mmm
Occurs rarely as surface coatings and masses and as micro-crystals.

I: STRATIGRAPHY OF THE GENESEE GORGE AT ROCHESTER
The Genesee River, in its northward flow to Lake Ontario, plunges over the Niagara or Lockport Escarpment at Rochester. Diverted from its preglacial outlet through Irondequoit Bay, the Genesee River, since the last ice retreat (8,000 years ago) has carved a post glacial gorge exhibiting a nearly complete exposure of Upper Ordovician to Middle Silurian rocks. Formations of the same age are superbly exposed in the Niagara Gorge and a comparison of the two sections reveals a Lower and Middle Silurian section ideally suited for the illustration of complex facies changes and/or disconformities.

STOP 1. Lower Falls and Gorge
Down from Seth Green Drive at St. Paul and Norton Streets, on east side of gorge below Driving Park bridge.
Group
Formation
Member
Lower Clinton
Reynales
Wallington Ls.
Furnaceville Hematite
Hickey Corners Ls
Maplewood Shale
Thorold Ss.
Medina
Grimsby Fm.
Queenston Fm.

STOP 2. Middle Falls and Gorge
At the bottom of Brewer St. down from St.Paul Street on east side of river; south of Driving Park Bridge and North of the Bausch Bridge (Smith St. Bridge)
Group
Formation
Member
Upper Clinton
Rochester Shale
Irondequoit Ls.
Williamson Shale
Lower Clinton
Lower Sodus Shale
Reynales Ls.
Wallington Ls.
Furnaceville Hematite
Hickory Corners Ls.
Maplewood Shale |

STOP 3. Upper Falls and Gorge
Down from Mill St. and Falls St., on access road to Rochester Gas and Electric Power Stations 2 & 3, on west side of gorge below Platt Street bridge
Group
Formation
Member
Lockport | Decew Dolomite |
Clinton | Rochester Shale |

46th Annual Meeting October 18-20, 1974
FIELD TRIP GUIDEBOOK
Donald N. Peterson, Editor
EDITORS NOTE
On behalf of the Department of Geology, State University of New York, College at Fredonia, I extend a cordial welcome to the participants of the 46th annual meeting of the New York State Geological Association. We hope that your participation will prove to be both enjoyable and educational.
I would like to acknowledge the contributors for taking the time to assist in the preparation of this guidebook. Although I was working with a slight handicap this year (the contributors represent eight different institutions), most of the deadlines were met with a minimum of prodding. Without their cooperation, our hosting of the NYSGA meeting would not have been possible, so, thank you.
I would like to express my gratitude to our departmental secretary, Mrs. Nancy Jagoda, who persevered with me in the preparation and typing of this guidebook, answered correspondence, and performed numerous and sundry jobs in helping to organize the meeting. Thanks also go to Mssrs. Don Burdick and Ron Warren of the Fredonia State Instructional Resource Center who helped in the preparation of some of the illustrations for this guidebook. Last, but not least, I would like to thank Mr. Joe Woloszyn and his staff at the campus print shop who did such a fine job of printing and binding the guidebook.

A: LOCKPORT (MIDDLE SILURIAN) AND ONONDAGA (MIDDLE DEVONIAN) PATCH REEFS IN WESTERN NEW YORK
Donald J. Crowley
State University College, Fredonia, N. Y.
(Field Trip Leader) and
Richard Z. Poore
Brown University
Providence, R. I.
A recent flourish of oil and gas exploration in the, Appalachian Basin has increased the interest in Silurian and Devonian reefs in New York and surrounding states. Although the companies do not expect to find reefs as large as those in the Michigan Basin, recent production of natural gas from Onondaga reefs around Steuben County, N. Y. has been sufficient to bring about a search for other Devonian reefs as well as Silurian reefs.
Patch reefs in the Lockport Formation (Middle Silurian) and Onondaga Limestone (Middle Devonian) are exposed along the northern edge of the Appalachian Basin in Western New York and have been studied in detail. Lockport reefs, occurring in the Gasport Member have been studied by Crowley (1973) and one Onondaga reef near LeRoy, N. Y. has been studied by Poore (1969). The object of this paper and accompanying field trip is to compare the Gasport reefs with the Onondaga reef.

STOP 1. Road cut on escarpment in the village of Pekin
Two patch reefs in the Gasport Member (Lockport Fm) are exposed on the west side of the road cut (See Fig. 4 in report). Lower few feet of the overlying chert-bearing Goat Island Member are also exposed.

STOP 2. Railroad cut on the east side of "The Gulf"
Railroad cut on the east side of "The Gulf", 1.3 miles east on route 31 from intersection with route 78 in Lockport. Lockport 7.5' quad.
2012: As Route 31 is not in the railroad cut, this stop has been located in the railroad cut, about 1.3 miles east of the intersection between Routes 78 and 31.
DeCew Member and the crinoidal bar facies of the Gasport (Lockport Fm.) are exposed. This is the most fossiliferous exposure of the Gasport and preservation of fossils is also good. Coral thickets form lenses in the crinoidal bar facies.

STOP 3. Frontier Stone Products quarry
All Gasport facies (Lockport Fm.) are exposed including several patch reefs. Stromatoporoid cap facies forms light band near the top of the quarry walls. A few feet of the Goat Island Member is exposed above the light band and the floor of the quarry is the top of the DeCew Member.

STOP 4. Abandoned quarry ("LeRoy quarry").
Patch reef in Onondaga Limestone exposed in the middle of the quarry. Edgecliff and the lower part of the Clarence member exposed around the outside quarry wall. (See Fig. 8 in report for cross section of reef).

B: UPPER DEVONIAN STRATIGRAPHY OF CHAUTAUQUA COUNTY, NY
A BRIEF DESCRIPTION OF UPPER DEVONIAN UNITS TO BE OBSERVED ON CHAUTAUQUA COUNTY FIELD TRIP
Irving H. Tesmer
Geosciences Department
SUNY College, Buffalo, NY 14222
PREVIOUS WORK
The first major work related to the geology of Chautauqua County appears in James Hall's (1843) Survey of the Fourth Geologic District. Chautauqua County stratigraphy was later studied in greater detail and modified by such workers as Clarke (1903), Chadwick (1923; 1924), Caster (1934), Pepper and de Witt (1950; 1951) and de Witt and Colton (1953). New York State Museum Bulletin 391 (Tesmer, 1963) describes the stratigraphy and paleontology of Chautauqua County.
Devonian stratigraphic nomenclature pertinent to this region his been subject to various interpretations (e.g., Rickard, 1964 and Oliver et al., 1969). In this guidebook, the present author follows the-stratigraphic terminology used in his other publications (Tesmer 1963; 1966; 1967; 1974; Buehler and Tesmer 1963).
NOTES ON THE AMMONOID AND CONODONT ZONATIONS OF THE UPPER DEVONIAN OF SOUTHWESTERN NEW YORK
William Kirchgasser
SUNY College at Potsdam
The sequence of zones currently recognized for the upper part of the Upper Devonian of New York is based on research by House (1962, et al.) on the ammonoid (goniatite) cephalopods and by Hass (1958) and Huddle (in Oliver and others, 1968 and Klapper and others, 1971) on conodonts. During the course of their studies of the succession in southwestern New York the author has had the opportunity to work with Michael House and John Huddle and the notes which follow summarize their reports to date. The zonations and the horizons from which biostratigraphically important faunas have been recorded are shown in Figure 1. Although the New York record for the upper part of the Upper Devonian is far from complete, correlations have been made at several levels with the standard zonal sequences of Europe.
Above the Dunkirk Shale, horizons yielding determinable ammonoid and conodont faunas decrease in frequency as the offshore shales with calcareous horizons and pelagic faunas interfinger with and are overlain by thick sequences of silty shales, siltstones and sandstone with benthonic faunas, and non-marine units in the upper part. The Dunkirk is the highest major black shale in the succession and above this level the subdivision and regional correlation of the rocks have proved to be more difficult than lower down in the section where black shale horizons provide stratigraphic control. Because key faunal horizons are scattered and difficult to trace, the positions of many zonal boundaries are not known with certainty.
Ammonoids are rare in New York above the Gowanda Shale and, in this part of the succession, conodonts would seem to offer the most promise for further zonal refinement.

B: UPPER DEVONIAN STRATIGRAPHY OF CHAUTAUQUA COUNTY, NY

Several levels of river terraces
Several levels of river terraces are exposed on each side of the bus at this point associated with higher stages of Lake Erie.

Cross Canadaway Creek Bridge.
Good exposures of the Gowanda shale at this point continue upstream to Laona, NY.

Stream terraces and an oxbow lake
Well-defined stream terraces can be seen on the right side of the bus. An abandoned oxbow lake can be observed 25 feet above the present level of the creek.

Type section of the Laona Siltstone
100 feet to the right (west) of this intersection is the type section of the Laona Siltstone exposed in a small waterfall.

Road cut through semi-stabilized landslides on left of bus.
Hill is composed of till overlying proglacial lake deposits. The creek flows in bedrock 200 feet to the right (W).

Exposures of the Westfield Shale are seen on the right side of the bus.

STOP 1. Shumla Siltstone
Exposures examined here are the type section of this unit. The lower contact is exposed downstream from the bridge. The underlying Westfield shale includes interbedded siltstones and shales. The base of the Shumla is marked by a massive siltstone which grades upward into increasingly thinner bedded units. These strata in turn grade upward into interbedded siltstones and shales which characterize the overlying Northeast shale. Trace fossils are abundant in several zones in these outcrops as are sedimentary structures including ripple marks, flute casts, and soft sediment deformation.

Passing the crest of the Pleistocene beach ridge of Glacial Lake Whittlesey.

The bus will pass over the Lake Warren beach complex in the next 0.3 miles.

Crest of Warren II beach
Mobil station on the right is near the crest of Warren II beach and it displays the best topographic expression of all the beaches along this traverse. Dunkirk Ready-Mix plant is located in the beach deposit.

STOP 2. Hanover Shale and Dunkirk Shale
Exposures allow the examination of the contact between the grey-green Hanover Shale and the black, fissile Dunkirk Shale. Numerous pyritized worm burrows and carbonized plant stems are seen at this locality. Rare specimens of the inarticulate brachiopod Barrolsella compbelli have also been collected. Exposures of a "bedded" till are also exposed along the eastern side of the headland overlying a striated surface of Dunkirk Shale.

On left is gas wellhead
On left is gas wellhead, one of approximately 60 wells drilled during the past 2 years in Chautauqua County. Production comes from the Silurian Medina Sandstone.

Bridge over Little Canadaway Creek.
Exposures are in the South Wales Shale.

Bridge over Slippery Rock Creek.
Exposures include the South Wales at the lake shore and Gowanda Shale at the bridge and upstream.

Bridge over Corell Creek.
Exposures are the Gowanda Shale.

STOP 3. Gowanda Shale, Corell's Point Fauna
Park on shoulder beyond the entrance to the trailer park on the right (N) side of the road. Walk down to the beach turn to the left (SW) and proceed approximately 100 yards.
Exposures at about lake level continue for approximately 100 yards. Cephalopods are pyritized and concentrated in bands, the most prominent of which is approximately 2 feet below a conspicuous zone of very large septarian concretions. This exposure is also notable for the bedrock-till contact which includes till injected along bedding planes and the incorporation of large blocks of bedrock in the till.

Elongate glacial landforms
On the left of the bus (S) observe the elongate glacial landforms which characterize this specific portion of the lake plain. These deposits may represent reworked sand deposits of higher lake stages.

Bridge over unnamed creek.
Exposures of Gowanda Shale include a 15 foot waterfall at the lake.

Bridge over Bournes Creek.
Exposures of Gowanda Shale and Laona Siltstone.

First Lighthouse illuminated by natural gas in U.S.A.

Crossing Glacial Lake Whittlesey beach crest?

Bridge over Little Chautauqua Creek gorge.

Pull off road onto shoulder for overview.
Stop is located on the lake escarpment moraine. Optional lake plain overview.

Chautauqua Lake.
Field trip route will traverse over Pleistocene and Recent Alluvial sand and silt for the next several miles.

Route now travels over Kent ground moraine.

Cross Prendergast Creek and drive onto Kent end moraine.

STOP 4. Panama Conglomerate Member of the Cattaraugus Formation
Exposures examined here constitute the type section of this unit. A thickness of approximately 70 feet is exposed. The conglomerate is cross-bedded in part and consists predominantly of milky quartz with occasional jasper pebbles averaging less than one inch in diameter. Localized weathering and erosion along joints account for the various "dens", "alleys", and special shapes which characterize Panama Rocks Park.

Kent end moraine
Route between Panama, NY and Ashville traverses over a Kent end moraine which is somewhat older than the one observed at mile 44.5.

STOP 5. Ellicott Member of the Chadakoin Formation
Exposures in this Erie-Lackawana railroad cut are very fossiliferous. The fauna includes brachiopods Camarotoechla, Cyrtospirifer and Productella and pelecypods Leptodesma and Mytilarca.

STOP 6. Dexterville and Ellicott Members of the Chadakoin Formation
The exposures in this inactive quarry represent the type section of both members. The lower unit, the Dexterville, is predominantly shale. Good fossil collecting is possible from both members at this location. Pugnoides duplicatus is restricted to the Dexterville strata and has been used as an index fossil for that unit. Rare specimens of very poorly preserved glass sponges have been collected from these exposures.

Airport overview.
Panoramic view of the glaciated terrain. Uplands are predominately Kent ground moraine. Glacial streamlining is very obvious.

Kent stratified drift deposits.
Between Gary, NY and Sinclairville, Route 60 traverses a series of Kent stratified drift deposits. The flood plain of Cassadaga Creek observed on the left (W) of the bus is recent alluvium and stream gravels.

Outwash plain of lake escarpment moraine
complex.

Bedded sands and gravels in pits behind
trailers.

Lake escarpment moraine front .

Typical morainal topography.

Landslides in complex glacial deposits
Landslides in complex glacial deposits which include varved clays deposited in a proglacial lake as well as till of Lake escarpment age.

C: LATE MIDDLE AND EARLY UPPER DEVONIAN DISCONFORMITIES AND PALEOECOLOGY OF THE MOSCOW FORMATION IN WESTERN ERIE COUNTY
Carlton E. Brett
SUNY at Buffalo
Since the time of Cooper's (1930) survey of the Hamilton Group in New York State, it has been well established that the stratigraphic sections exposed in Erie County are relatively incomplete compared to the section in Central New York, particularly in the upper Hamilton Group. Clastic sediments derived from highlands to the east often failed to reach western New York. Thus, thin lag deposit limestones and scoured contacts between members or individual beds may be time equivalent to thick sequences of shales and siltstones in the east.
In western New York the Windom Member of the Moscow Formation is bounded above and below by unconformities representing two fairly major periods of non-deposition. Careful examination of the contacts provides evidence that these were also periods of erosion suggesting local shoaling of the seas. These disconformities are described in some detail in the present paper because of their implications in the interpretation of the depositional environments of the Moscow and overlying (Upper Devonian) Genesee Formation.
The study area covered in this report (Fig. 1) includes all outcrops form Cazenovia Creek at Spring Brook (Orchard Park 7.5 min. quad.) to Pike Creek near Derby, NY (Eden 7.5 min quad.) a total distance of about 20 miles.

C: LATE MIDDLE AND EARLY UPPER DEVONIAN DISCONFORMITIES AND PALEOECOLOGY OF THE MOSCOW FORMATION IN WESTERN ERIE COUNTY

STOP 1. Cazenovia Creek at Northrup Rd.
A good exposure of Ludlowville Moscow contact can be seen on the left bank just downstream from the bridge. A thick section of Tichenor Limestone with basal shaley layer containing large favositids is overlain by the Trachypora bed of the Kashong Member about 11-14 in. thick containing abundant crinoid columnals, the coral Trachypora, large pelecypods, and gastropods. The base of the Moscow is the contact between the Kashong and Tichenor. The Kashong-Windom contact is marked by a rusty layer containing abundant crinoidal debris and Ambocoelia umbonata with occasional reworked specimens of Trachypora from the underlying Kashong. About 74 in. of Ambocoelia beds are present in the lower Windom here followed by (inaccessible) ledges of the calcareous Spinatrypa and coral-trilobite beds.
At the falls east of Northrup Road, the Tichenor lower contact with the fossiliferous Wanaka shale can also be seen. High cliffs which can be seen in the distance upstream from the falls exposes about 40 ft. of Windom capped by the black Genesee shales and Genundewa limestone.

Proceed down dirt path on the left side of the road near utility poles. At the bottom turn left and walk to exposure on Cazenovia Creek bank. Here the upper Windom Shale is at water level, the Genundewa Limestone of the Genesee Formation forming a projecting ledge. About 1 mile downstream is a good exposure of the Moscow/Genesee contact. About 20 in. of black Geneseo shale separates the Upper Windom (Praeumbona Beds) from the Genundewa. At intervals, lenses of Liecester Pyrite 0.5-6 in. thick occur at the contact. These are fossiliferous and contain an assemblage of diminutive brachiopods and mollusks. One lens along this section shows interbedding of the pyrite with black Geneseo shale. The basal layer of the Genundewa at this locality contains abundant, well-preserved fish bones.

Bridge on U.S. 20 over Smokes Creek
Bridge on U.S. 20 over Smokes Creek (Type locality of the Windom is north, downstream) Orchard Park Stadium on left side.

STOP 3. Cloverbank Quarry.
Leased quarry of Lehigh Cement Co., on east side of Versailles-Pennsylvania R.R. tracks about .3 miles southwest of the intersection of the tracks and Clover Bank Road.
The Quarry walls about 50 ft. high expose the Upper Devonian Middlesex-Cashaqua Shale, floored mainly by the shaley upper contact of the Genudewa limestone and the West River shale. In a narrow pit the Genundewa is breached and a section extends down some 8-10 ft. to, or just below, the Praeumbona bed of the Windom shale. The Windom here is in contact with the North Evans Limestone and the contact is an erosion surface showing characteristic "rip-up" horizon. The uppermost Windom bed is a concretionary, calcareous, grey (1-3 in.) shale or argillaceous limestone. It appears to be unfossiliferous. The upper layer is undulating and pieces of this layer have been incorporated into the overlying North Evans as "slices" which appear to be cracked and torn up. Others occur as rounded chunks. The crinoidal debris of the North Evans appears within cracks in few Windom upper layer as if injected. Some of the pieces of the upper Windom bed have greenish stains on the surface suggestive of glauconite. The North Evans contains much debris including abundant fish plates and teeth, phosphatic nodules, much pyrite (note rusty stains), and a few invertebrate fossils : crinoid plates and rugose corals. The Genundewa itself is only about 6 in. thick and quickly grades into a somewhat sandy shale (West River). It is in direct undulating contact with the underlying North Evans although in places this contact is obscure.
2012: GE photo from 3/27/95 shows quarry before real estate development. Since then, it looks like it's gone...

Town of Wanakah.
Type locality for the Wanakah shale (Ludlowville Formation).

STOP 4. Eighteenmile Creek
Section 5 About 1/4 mile south of the bridge at route 5 over Eighteenmile Creek, the creek makes a major U-bend and swings around from southwest to northeast. Due south from the bridge on the left side of the stream is a large meander scar, then the bank rises steeply where the stream is actively cutting into the Tichenor Limestone. Here the Tichenor forms a slightly undercut ledge about 1-2 ft. from the water edge, for about 1/4 mile to a small falls. The lower beds of the Windom Shale (here about 17 ft. thick) are easily studied here. The upper 1-3 ft. or so of the Wanakah which is exposed here is quite fossiliferous. The Tichenor is 1 foot thick, massive and contains abraded crinoid columnals and other fossils. Its upper surface is notably rich in the pelecypod Plethomytilus here, and contains traces of burrows. At this locality a zone of shale about 3 in. thick in direct contact with upper Tichenor Limestone contains waterworn fragments of brachiopods (Spinocyrtia), limestone pebbles eroded from the underlying Tichenor, and rounded black pebbles (0.2-0.5 in.) probably phosphatic. A large crinoid root (scutella-form) was in place on the upper surface as well as bored and abraded shells. The lowest 2 ft. of the Windom contain the extremely rich Ambocoella beds, and these are overlain by classically developed coral beds (3 in. thick) with large Cystiphylloides and the brachiopods Atrypa, Spinatrypa, followed by one foot of calcareous shale containing Amplexiphylloldes, Stereolasma, Mucrospirifer consobrinus, and well preserved trilobite remains. Poorly preserved Nuclulites are found in the middle of these shales and just a few inches above the "trilobite-coral" layer a few pyritized fossils (Bucanopsis and nautiloids) were obtained. Associated with these (just below) was a thin unfossiliferous, calcareous lens and above some Mediospirifer and corals were collected.
Most of the overlying shales are barren, although near the top, the slightly concretionary calcareous Praeumbona bed contains abundant brachiopods. The Genundewa Limestone overlies the Windom about 17 ft. above the Tichenor. Fallen blocks reveal a thin coating of "Conodont bed" adhering to the underside of the Genundewa. This unit contains pieces of upper Windom argillaceous limestone as well as dark shale pebbles.
The section is capped by about 20 ft. of Genesee Formation and massive jointed Middlesex black shale fallen blocks of the yield plant remains.
Section 4. Proceeding upstream from the falls at section 5, Eighteenmile Creek bends to the south. About 500 ft. above the falls a steep bank on the south (right) side of the creek exposes a section of some 75 ft. (Section 4). At the top of the bank the black Rhinestreet Shale (Upper Devonian, West Falls formation) forms a nearly vertical wall. Below it is the greenish-grey Cashaqua, blocky black Middlesex Shale (two members of the Sonyea formation), and a dark-grey West River Shale. The Genundewa limestone forms a projecting ledge at the base of the cliff. The "Conodont bed" (North Evans) is either missing or occurs as very thin patches on the underside of the ledge. A few feet of Windom crop out beneath the ledge. The creek is very deep next to this section and therefore it is difficult to examine in detail.
Section 3. Opposite the upper end of section 4 the creek swings back north and cuts the end of a promontory on the north side of the channel. Here an easily accessible section of upper Windom to Cashaqua can be seen. Note the double concretionary layer in the upper Windom. The basal Genundewa has black shaley seams, but the "Conodont bed" is apparently absent here.
Section 1. If time and creek conditions permit, we will proceed around the end of the promontory and upstream (east) about 500 ft. to exposures on the left bank near the trestle of N. Y. Central Railroad. Here in the type locality, the North Evans Limestone thickens to a maximum of about 4 in. In places, interbeds of dark shale separate the North Evans limestone into two bands. The unit is also separated from the overlying Genundewa by a black shale seam.
Return to the bus via a dirt path running from the end df the promontory at section 3 to the end of Basswood Drive. Access to sections of Eighteenmile Creek from private lands has been provided by kind permission of the owners, Mr. S. Prahovic and Mr. W. F. McLimans. Please respect this privilege.

D: FROM LAKE ERIE TO THE GLACIAL LIMITS AND BEYOND (or What the Glaciers Did For Us)
E. H. Muller
Geology Department
Syracuse University
R. K. Fahnestock
SUNY, Fredonia
Today's trip will take us from Fredonia southeastward to Olean returning by way of Otto (The route and features of this trip will be found on Plate 1). Leaving the Erie lake plain in the morning, the route crosses the glaciated plateau to the edge of the unglaciated Salamanca re-entrant. Topographic features and surface glacial deposits are progressively older southward, ranging from nearshore deposits of Lake Warren across moraines of the plateau margin to early Wisconsin features of the Olean drift border. Deposits of post-Sangamon, pre-Farmdale age will be studied in exposures at Otto.

D: FROM LAKE ERIE TO THE GLACIAL LIMITS AND BEYOND (or What the Glaciers Did For Us)

Continue up the Water Street hill
Continue up the Water Street hill, climbing above the creek terraces graded to the Lakes Warren and lower levels of the glacial Great Lakes.

Beach-delta complex of Lake Whittlesey
At the top of the hill the level plain is a beach-delta complex formed at the Lake Whittlesey level, 830 ft. at this point. Lake Whittlesey shoreline rises about 1 foot per mile toward Buffalo.
To the Southwest a drift-free bench (1) (the circled numbers refer to location on Plate 1.) marks one of the many ice marginal drainage channels. The north wall of this channel must have been the glacier. Beyond the bench lies the escarpment. The escarpment which separates the lake plains from the plateau has been called the Portage Escarpment, but it is developed on the Canadaway Formation in this area. The escarpment bears no relationship to the Portage Group, which does not crop out in Chautauqua County. The Canadaway Formation totals about 950 feet and is composed dominantly of shale. The Laona and Shumla Members, each about 30 feet thick are largely siltstone and somewhat thicker-bedded than the other members. These two siltstone members may account for details of the character of the scarp as developed eastward toward Forestville.
Question: In view of the dominantly shale lithology exposed in this portion of the escarpment, is structural control an adequate explanation of the origin of this scarp? Regional dip is very gentle toward the south. If the topography be truly cuestaform, where are the resistant capping strata responsible for the scarp which is 700 to 1100 feet high in eastern Chautauqua County?

Village of Laona
Turn east, crossing Canadaway again in the village of Laona. On the south side of the bridge, (2) a mill dam, its pond now filled with debris, raises the height of the waterfall over the Laona siltstone under the bridge. One hundred and fifty years ago Laona, like all towns was a major user of water power. The county historian points out that about 35 factories drew their power from the Canadaway and it is said that there were at least seven dams in Laona alone. Anyone considering floodplain landforms must keep in mind both man and beaver as geologic agents.

Buried valleys
Heading south on Route 60 we pass through a broad open valley with only isolated patches of bedrock exposed (3). This is a post-glacial excavation of a complex of buried valleys. The streams of this area have made similar excavations each time the glacier retreated from the escarpment. The buried valleys (also featured on tomorrow's trip F) have a variety of forms from steep-walled canyons (Fig. F1) to broad, open valleys with gentle walls (Fig. F5).

STOP 1. Route 60 Landslide Area.
This area will also be visited tomorrow on Trip E, Environmental Geology. You may wish to consult the descriptions of the landslides and associated problems with the Fredonia Reservoir.
The glacial sequence consists of till, lake rhythmites, and till. The landslides start with a failure at or near the lower contact of the lake beds. Although the upper contact of the lake beds has not been observed, it is thought to be relatively undisturbed. If so, a till flow, a la Hartshorn (1958, 1960) may be a possibility.
There are about 20 feet of interlayered clays and silts which may represent (A) annual pairs (varves) or (B) storm pairs resulting from disturbance and more rapid settling of the silts; or (C) maybe you have an idea. If (A), this small lake lasted longer than some or all of the Glacial Great Lakes. If (B) it didn't. Cloture will be invoked after 10 minutes to allow vote of all present to be taken to settle the matter for all time.

Cassadaga Lakes
Continuing South on Rt. 60, a brief side trip to the Cassadaga Lakes will be made to show the evidence of formation from the melting of ice blocks buried in outwash. The Cassadaga Lakes (5) lie between the Lake Escarpment (4) moraines to the north and remnants of a slightly older moraine to the south.

Cassadaga Valley
Continue south on Rt. 60 through the Cassadaga Valley which is filled about half way from the bedrock floor to the adjacent summits. A well near Gerry has penetrated 600 feet of fill. In contrast to the thickness of fill in the valleys, the streamlined drumlinoidal topography of the uplands is covered in most places by a veneer of ground moraine (basal till plastered on under the glaciers).

Groundwater issues near Holmquist Creek
Crain (1966) recognized that the Jamestown water supply was independent of the flow of Cassadaga Creek as heavy pumping of adjacent wells had no effect on the creek. This is thought to result from lake silts and clays near the surface of the valley fill acting as an aquiclude. The pumping did, however, show effects on permeable zones within the valley fill. These zones known as the Jamestown aquifer occur at lower elevations as one goes northward raising the question of what permeable deposit would dip northward, up glacier or up valley.
Obvious water losses, of the streams tributary to Cassadaga Creek, occur as they flow across the "alluvial fan-deltas" which occur along the valley margin where the relatively steep streams emerge onto a flat valley floor. These water losses suggested to Crain the relationships between the tributary stream deposits and the aquifer shown in Figure D3. The losses are not as obvious if one follows the streams out onto the valley floor where a major part of the "lost" water reappears. Here it flows in tightly meandering channels as the "deltas" thin toward their margins and the effects of the lake deposits are felt.
The Sinclairville (8), Gerry (6), Holmquist(9)and Folsom (10) "deltas" are among the "recharge" areas mapped by Crain.
Agnes caused considerable damage in many areas of New York, but a study of Holmquist Creek by Winter (1974) revealed that very little erosion or deposition occurred. The spring meltwater flows appeared to be significantly more effective in moving sediment and causing change. On high gradient streams with small drainage basins like Holmquist Creek, intense events covering much smaller areas are the prime movers and land sculptors. Events with a recurrence interval of 100 years or more play a much more important role than do events like Agnes with a 25 to 50 year interval.

Ice contact stratified drift
On NY 394 (old route 17) we will head eastward crossing ice contact stratified drift (11)

Skirt the north edge of the Hartson Swamp
Skirt the north edge of the Hartson Swamp (12) which lies atop thee Poland aquifer, a permeable zone in the Conewango-Cassadaga valley fill. Aside from the permeable zones in the valley fills, groundwater is not abundant. In the uplands limited quantities can often be produced from zones of broken bed rock at the contact with overlying drift. Where the drift is thin or lacking and ground water must be produced from the local shales and siltstones, there is little of it and the quality leaves much to be desired.

Climb the valley of Mud Creek
Crossing the Conewango from Roland Center the route climbs the valley of Mud Creek (13). Note the gradient and character of the stream and valley floor. We will attempt to compare this valley with that of Elkins Brook (14), the next one to the north, in order to determine whether the present streams fashioned either valley.

Elkins Brook valley (14)

Knob and kettle topography
On the upland, the route will traverse the glacial boundary crossing and recrossing it at several places. At some points we will be in knob and kettle topography with as much relief as any of the younger moraines to the north (15). While there are some evidences of glaciation such as foreign cobbles and boulders a few hundred yards beyond the obvious moraine, the changes in relief in the upland are not as striking as in the valleys. We will travel beyond the region affected by glaciation and along its fringes and then return through the sequence of moraines and filled valleys typical of New York State. A major point of this field trip is the contrast between unglaciated, marginal, and repeatedly-glaciated terrain.

Former kame delta
Large quantities of gravel for the new route 17 (The Southern Tier Expressway) were removed from a large kame delta which has since been landscaped.

STOP 2. Refer to Plate 2c and d
Dropping off the north side of the glaciated upland into the Ancestral Allegheny Valley now occupied by minor tributaries of the Conewango, we will pause for a view of the ice contact face (17) of the Kent terminal moraine and related features on the valley floor. The valley before us is the site of the reservoir advocated by Arthur Morgan (1971, Dams and other Disasters) as an alternate to the Kinzua Reservoir we will cross later. While Morgan was careful to not publish any maps, his plan would appear to make sense increasing the safety of the Allegany drainage while living up to George Washington's promises to leave the Indian lands untouched "so long as the sun rises and the river runs" in the works of the Pickering Treaty, the oldest existing U.S. Treaty (Morgan, 1971, p. 318).

Post-glacial Allegany valley
The route winds by the most direct path now available, through the town of Steamburg Rt. 394 (old Route 17) and south along the Kinzua Reservoir (18) on Reservoir Rd. in the post-glacial Allegany valley to Hotchkiss Hollow.

STOP 3. Quarry just into Hotchkiss Hollow.
"Devil's concrete" (conglomerate) has preserved the bedding of this quarry in striking contrast to most gravel deposits. What does the bedding indicate about the direction of the gravel source? What is the significance of the lithologies present in the gravel? What can you make of the feature blocking the mouth of the valley and of the form of its surface from which we just descended?

Traverse the glacial margin
In this portion of the trip we will traverse the glacial margin, but the final route has not been established as of this writing. In any case, we must return north to cross the Allegany on new Route 17. Wisconsin valley train has been quarried for the Route 17 fill (19). A terrace remnant of valley train (20) is deeply cut for the new route on the SE side of the river (Expletive deleted Landscaping!) (21) The new highway construction has triggered numerous landslides, rockfalls and mudflows. A route through Salamanca, Kilbuck, and Limestone, or an alternate route along the reservoir and south of the Allegany State Park may be taken (NY Rt. 220 to PA Rt. 346).
On either route, contrasts between glaciated valleys and valleys in which the only effects are those of lakes like the one in Hotchkiss Hollow and valleys untouched by any glacial effects will be seen..

Oil wells
As we approach Bradford (the home of Kendall Oil Co.), many wells producing in the manner of the early oil industry can be seen. A pump house and wells of this type will be seen at STOP D4 in Rock City.

Derrick City
Turn east onto PA Route 646 at Foster Brook (22) staggering through Derrick City and up over the Knapp Creek (23) summit to Rock City.

Old inter-urban railroad line
The route becomes NY 16 at the state line. It follows the old right-of-way of the Western New York and Pennsylvania RR interurban between Bradford and Olean which followed the route of a narrow gage railroad built in 1878 to haul oil.

STOP 4. Olean conglomerate weathering escarpment.
Olean Rock City, Allegany town, Olean quadrangle, Cattaraugus County (78°28'30"W, 42°1'N).
This is the type locality for the Olean conglomerate (Lesley, 1875), exposed in weathering scarp 64 ft. thick. Cross-beddng, joint cracks and ellipsoidal quartz pebbles to more than 30 mm in length are characteristic. This unit occurs on summit remnants of the Upland peneplain as far east as Alma Hill in Allegany County at 2548 feet above sea level, the Highest elevation in western New York. Southward into Pennsylvania, the formation loses its conglomeratic character in 20 to 30 miles.
This ledge consists of joint blocks separated by interconnecting passages which widen toward the exposed scarp face. Near the parent ledge, the joint blocks show a minimum of rotation and subsidence, but outwards they show varying amounts of tilt and downward movement. Noting that the blocks appear now to be immobile and disintegrating in place, Smith (1953) identified this and other nearby "rock cities" as periglacial features. A similar, though less striking, rock city in the area of Early Cary glaciation is at Panama Rocks, Chautauqua County.
Question: What evidence is there as to the relative importance of weathering, wedging, creep, sapping or other processes to produce this display of joint enlargement? What evidence shows the blocks to be immobile and the rock cities to be relics of periglacial environments?
The following paragraphs from Cochran (1957) on the production of oil is applicable to the oil fields around Rock City.
In the Allegany (Bradford area) field primarily two different means are used in pumping wells, that is the individual well jack and the Oklahoma style Jack pumped by a central power. The main difference in these two methods is that the individual well jack is a unit complete in itself with a motor to supply power to the jack for lifting the rods and bottom hole equipment. The power to the Oklahoma style jack is supplied by a cable or rod line from the eccentric of the central power.
Two different types of central powers are in use today, the gear power and the bandwheel power. The gear power uses a gear and pinion powered from the engine by a belt to motivate the eccentric whereas the bandwheel power uses a horizontal band wheel powered by a belt running from the engine to motivate the eccentric.
Generally about 25 wells are pumped off of one central power. About four barrels of fluid per hour can be pumped from each well. Since this is normally more than will flow into the well bore it is not necessary to pump all the wells simultaneously, and the pumping times of the individual wells may be staggered throughout the pumping period.
Note: See Cochran (1957) for information on water flooding, well shooting and other aspects. A detailed and readable account of the early New York oil industry is contained in Herrick (1949).

Harbell Farm Well No. 1
In village of Knapp Creek, turn right (north) onto County Road 61 which drops sharply into valley of Four Mile Creek. Harbell Farm Well no. 1 the state's oldest oil well which has produced continuously since 1811 (Herrick, 1949) lies in this valley.

Rockview
Rockview (24) the first of six boom towns to spring up in and around the Four Mile valley in 1877 had 6 stores and 70 homes. Other towns included Rock City, Knapp Creek and Stateline.

West Branch Four Mile Creek
West Branch Four Mile Creek lies to the west across the valley. Distribution of erratic pebbles and cobbles suggests that this is the approximate limit of glaciation in the valley of Four Mile creek (25).

Terrace gravels
Foundation excavations at left exposed terrace gravels with several per cent of crystalline pebbles, leached more than 8 ft.

Terrace remnant
To the right, ahead, a flat-topped ridge extends northwest, confining the flood plain to one-third of the valley width. This terrace remnant is poorly exposed, but is believed to consist of gravel, leached to 8 or 10 feet and overlain by several feet of yellow-brown silt and silt loam. The elongate form of the ridge suggests ice-marginal deposition, perhaps as an outwash delta. A tempting explanation for ponding in the Allegheny Valley is by glacial damming. Such impounding did not occur downstream from this point in Olean or later time.

Road to abandoned rock quarry
Unmarked road to left leads to abandoned rock quarry and upper levels of STOP D5.

STOP 5. Kame delta complex.
Allegany Sand and Gravel Pit, Buffalo Slag Company. Birch Run at edge of Allegheny Valley, 0.9 miles SE of Russell, Allegany town, Salamanca quadrangle, Cattaraugus County. (78°32'50" W, 42°5'25"N).
Exposures in kame delta at several levels. Gravel is leached 9 to 12 ft. Carbonate content low, comprising only a few per cent of pebbles. Cementation by secondary carbonate is limited. Cobble imbrication, foreset bedding and slump structures suggest deposition toward west. In upper level as exposed in 1959, 40 feet of boulder-free cobble gravel overlay 15 feet of sand over 10 feet of till. Till is olive brown, silt loam matrix, low in lime, with coarse fraction consisting primarily of stream-worn pebbles and flaggy boulders.
Search for erratic pebbles revealed none more than a mile south up the valley of Birch Run, nor could any be found on the south side of valley of Birch Run. A few erratics in the saddle at 1760 feet, 3/4 mile southeast of the pit confirm the inference that proglacial meltwaters drained across the saddle south from Allegheny Valley into the valley of Birch Run.

Lippert Sand and Gravel Pit about one mile east
Lippert Sand and Gravel Pit about one mile east produces from outwash gravel below river level.

Bradford Junction.
Turn west on N.Y. Rt. 17 through Salamanca noting terrace remnants along the way. Salamanca is one town that cannot be given back to the Indians; they already own it and the lease does not have many years to run.

Look for glacial remnants
On the west side of town, turn north on NY 353 toward Little Valley. As we proceed, try to spot the outermost evidence of ice action, the remnants of outwash terraces, the terminal and recessional moraines.

STOP 6. Wisconsin stratigraphy.
Otto high bluff section, stream-bluff of South Branch Cattaraugus CreekOtto town; Cattaraugus quadrangle, Cattaraugus County. (78d50'W, 4202l'15"N).
The Otto site was initially described (MacClintock and Apfel, L944) as exposing Binghamton till, Olean outwash and Sangamon interglacial deposits. As exposed in recent year s (Muller, 1957) the lower portion of the section has been alternatively interpreted as evidence of post-Sangamon, pre•classical Wisconsin environments. Both interpretations are permitted by radiocarbon dating of the uppermost organic zone, 15 ft. above the river at an age of greater than 52,000 years (GRO 2565). See discussion in text section on pre-Farmdale organic sites.
Upper part of the section is obscured by slump. Units 6 through 11 below were measured at the south end of the exposure. Units 2 through 6 were measured nearer the north end where material for radiocarbon and pollen analyses was also collected.
Bedrock is exposed only at the south.
Unit | Lithology | Thickness
11 | Stratified sand, silt and clay | 3 ft.
10b | Till, gray-brown, sparsely pebbly silty clay loam matrix. Oxidized but unleached; bright pebble lithology; silt streaks | 20 ft.
10a | Till as above, unoxidized | 10 ft.
9 | Stratified sand, silt and clay with very sparse pebbles | 3 ft.
8 | Till, gray, sparsely to moderately pebbly, silt to sandy silt matrix; includes partings of washed drift suggestive of oscillatory conditions of deposition | 40 ft.
7 | Pebble gravel, grading downward with decreasing coarseness | 5 ft.
6 | Lake clay, contorted, laminated; red and "fat", in part. | 3 ft.
5 | Gravel, coarse, consisting largely of angular to sub-rounded pebbles and cobbles of plateau rock (sandstone and siltstone). Carbonate and crystalline cobbles are very sparse. What current direction is suggested by imbrication? A thin but continuous layer of silt and carbonaceous silt about midway up in this unit was dated at greater than 52,000 years (Gro-2565). | 20 ft.
4 | Stratified silt, muck, sand and pebbly silt. Both contacts transitional, not indicative of abrupt change of environment. | 4 ft.
3 | Boulder gravel, in a lens with maximum thickness at north end of exposure. Exact position in the organic sequence of units 2 and 4 is not certain. Boulders are tightly wedged with coarse sand to pebble gravel matrix. Platy cobbles and flats tones are dominant. Erratics and glacial striae are very sparse. Top of this unit is discolored by hydrous iron oxide deposition. Difficult to obtain effervescence with hydrochloric acid except on cobble coatings, which suggests secondary deposition | 3 ft.
2 | Stratified silt, muck, peat, suggestive of floodplain deposition. Twigs are flattened and peat highly compressed. Imbrication suggests deposition from southwest. Base of section concealed below river at north. Pollen from near the base (2a-7) includes primary Picea and Pinus (Brown and Benninghoff, personal communication, see p. 25f.) | 7. 0 ft.
1 | Boulder gravel, coarse with abundance of crystalline boulders, apparently lag concentration in channel which eroded pre-existing drift. A smear of till may exist beneath and among the boulders. | 3.0 ft.
0 | Bed rock; northward blue-gray siltstone with gradient northward | 6.0 ft.+
Questions: What is the significance of the oxidized horizon at the top of Unit 3? How is the Sangamon represented? What is the character of the interval(s) represented by Units 1 through 4? What change caused the transition deposition of cobble gravel, Unit 5?

This valley served as the outlet to Lake Zoar (Plate 2d).
The first outlet [5] continuing further south and the later outlet turning north at Cattaraugus following the present course of the South Branch of Cattaraugus Creek and the route of the Erie RR westward through the low at Persia. No roads and few trains follow this route today.

Markham (28) (a well penetrated 1100 ft. of fill near here)

Conewango Valley (29) (the Ancestral Alleghany)

E: SELECTED PROBLEMS OF ENVIRONMENTAL GEOLOGY IN CHAUTAUQUA COUNTY, NY
William J. Metzger State University College Fredonia, NY
LAKE ERIE SHORELINE EROSION
The problems of shoreline erosion in the Lake Erie basin as well as the other Great Lakes have received wide publicity during the past two years. As Table 1 indicates, the highest monthly averages of levels of Lake Erie on record were observed during 1973 (9 months) and 1972 (3 months). These record-high lake levels have a significant effect on the intensity of wave erosion and are probably the primary cause of the extensive erosion which has been observed during the last 2 years. At the time this paper is being written (June, 1974) the Chairman of Chautauqua County Civil Defense Unit is attempting to have the lake shore area of Chautauqua County declared a national disaster area. He suggests that there is a potential of $14 million damage to private property by lakeshore erosion.
Although the problem of erosion along the shoreline is very complex, several important variables can be demonstrated by the simple model indicated in Figure 1. Note that at times of normal lake levels, the water at the shoreline is in contact with bedrock which has a very low erosion rate under normal circumstances. The lake bottom area over which the wave energy is dissipated is very large. This condition produces a stable beach and wave erosion is not a serious short-term problem. In contrast to this, however, a high-water lake level will result in much more rapid erosion. In many places along the Lake Erie shore in Chautauqua County, the water level is presently very close to the top of the bedrock and is in contact with till in many others. As the lake level reaches this till-bedrock contact, and the waves can attack the unconsolidated till, the rate of erosion increases very rapidly. The wave action is now directed at the steepest portion of the shore zone and the lake bottom area over which wave action is dissipated reaches its lowest value. These factors combine to produce intensified erosion in the most easily-eroded materials exposed along the shoreline.
However, this is not the whole story. Figure 2 illustrates an additional factor which must be considered when trying to understand the increased rate of erosion along the shore. Notice in Figure 2 that the undisturbed (stillwater) level indicates that water will be in contact with bedrock and therefore result in low rates of erosion. This may be true for a given shore area even if the stillwater level is at a record high. However, short-term meteorological activity such as rapid barometric changes and storms may cause strong, prevailing winds to develop in the lake basin. This will result in a phenomenon called setups which causes the water to pile up on one side of the lake and the surface of the water to tilt in the basin. This is known as the storm setup. The amount of setup observed at any time varies with such factors as the intensity of the storm, the length of fetch associated with the prevailing winds, the bottom topography and the depth of water. The maximum setup values for Lake Erie are not constant, but they generally range from about 1.5 feet near Cleveland, Ohio to nearly 6 ft. at Buffalo. (Corps of Engineers, 1973).
With record-high water levels, a storm which results in the maximum setup for a given area is generally accompanied by large waves with amplitudes greater than 5 ft. These large waves, in combination with the high water levels, can result in extremely rapid shoreline erosion.
When the lake water levels are at the maximum, as we presently observe them, the higher intensity waves erode the sand on the beach and carry these sediments offshore. The beaches are narrowed by both the encroachment of the water and the removal of the sand to the offshore beach area. When the lake levels return to normal, this sand should be pushed back onto the beach by the lower energy waves.

E: SELECTED PROBLEMS OF ENVIRONMENTAL GEOLOGY IN CHAUTAUQUA COUNTY, NY

Route travels over lake bottom sediments or glacial Lake Warren.

Niagara Mohawk electrical generation plant
At this point on the north side of the road the Niagara Mohawk electrical generation plant can be observed. Power is produced by burning bituminous coal. The problems related to the disposal of the fly ash and bottom ash produced here will be discussed at STOP 3 of this trip.

Cross Canadaway Creek bridge

STOP 1. Lake Shore Erosion Problems
This area allows a comparison of the extent of erosion between areas which have sea walls with those areas without any erosion control. In one unprotected zone over 10 feet of embankment has been eroded away during the past 20 months. One house which will be visited is seriously threatened by the active erosion which has been intensified by the high lake stages.

STOP 2. Flood control structure and shoreline erosion problem
The project you are examining was completed in the Spring of 1973 by the Corps of Engineers as a flood control measure to prevent the flooding of the low lying areas near the cottages along this portion of the beach. To the North of the wall, the elevation of the land is sufficient not to justify flood control. However this area is not protected from wave activity and rapid erosion is now taking place in that area.

STOP 3. Fly ash-bottom ash disposal site
You will observe a trench and fill operation in relatively impervious lake bottom sediments which overlie till. The fly ash is dumped first and later covered with coarser bottom ash to prevent blowing of the very fine particulates. The ash is then covered over by the soil and glacial deposits removed in the original excavation. Attempts to control and monitor leachate will be observed including an on-site measurement of the conductivity of the water entering the pond.

Variety of glacial deposits and features.
The next segment of the trip will traverse a significant variety of glacial deposits and features. The highlights are noted in the log. At this point the bus is driving over lake bottom deposits of Glacial Lake Warren.

Lake Warren II beach ahead and to the left.
To the left and front of the bus note the line of poplar trees in the distance. They mark the location of the Lake Warren II beach.

Driving up the front face of the Warren II beach.

Inactive sand and gravel pit to the right
To the right of the bus observe the inactive sand and gravel pit. When in operation this pit is a good location to note the nature of the sediments and bedding characteristics of an ancient beach deposit.

Unnamed, poorly defined beach ridge.

Front face of the Lake Whittlesey beach.
Driving up the front face of the Lake Whittlesey beach. This is the highest proglacial stage recognized in Chautauqua County.

Crest of the Lake Whittlesey
Webster Road follows the crest of the Lake Whittlesey for the next mile on the trip route.

Lake Escarpment ground moraine
For the next 2 miles, the bus will travel over Lake Escarpment ground moraine as we gain elevation on the escarpment.

Penn Central Railroad (abandoned).
To the right of the bus observe the deep gorge which was used as the railroad right of way. This is a glacial meltwater channel formed during the deglaciation of this area when the ice blocked the normal outlet downslope to the north.

Lake Escarpment end moraine
This intersection marks the approximate northern boundary of the Lake Escarpment end moraine complex.

STOP 4. Agnes flood erosion and stream channelization problems
Pull off onto the far right shoulder of the road. Follow fence line down to the creek.
A very large landslide induced by greatly accelerated erosion during the Agnes Flood (1972) runoff is seen. The abundant supply of silt and clay from this material caused a serious siltation problem in the Village of Fredonia's Water Supply Reservoir located approximately 1.4 miles downstream. Agnes flood relief money allowed stream channelization upstream from this point to be completed in the summer of 1973. Since that time, extensive down-cutting on this stream has occurred which has contributed greatly to further siltation problems in the reservoir.

STOP 5. Stream contamination problems
Two sources of water contamination are apparent in this area. The first includes clay and silt which is being dumped down the embankment by the highway department. The second involves the unprotected pile of bottom ash and salt which is locally used for ice and snow removal on the highways during the winter. The small stream is tributary to the Village of Fredonia water supply.

Lacustrine clays, etc.
The bus is now traveling over a series of deposits that include clays deposited in proglacial lake. They will be observed at the next stop.

STOP 6. Landslides and badland erosion
This section of Route 60 was completed during 1958 and since that time a combination of slumping and earthflows have affected both sides of this cut. The glacial deposits involved in the slides are proglacial varved clays and at least two tills. The highway department has removed much material at the base of the slope which has caused further instability problems.
At the top of the hill an extensive "badlands" has developed where the soil has been removed or covered with clays taken from the road cut excavation. These clays are being washed into a tributary to the Village of Fredonia water supply reservoir.

Semistabilized landslides in similar deposits.

F: GLACIAL GEOLOGY AND BURIED TOPOGRAPHY IN THE VICINITY OF FREDONIA, GOWANDA, AND ZOAR VALLEY, NY
LOOKS AT THE PRESENT AND THE RECENT PAST
Ernest H. Muller
Dept. of Geology
Syracuse University
R. K. Fahnestock
S.U.C. Fredonia
A WORD TO THE FORE
We wish to acknowledge the stimulus provided by our respective chairpersons, Daniel Merriam of Syracuse and Olcott Gates of Fredonia who volunteered our services, and the gentle prodding of the guidebook editor. All were essential to the completion of this manuscript. The cooperation of the New York State Geological Survey and its director, Dr. James Davis, in permitting the use of appropriate portions of a draft of Muller's Glacial Geology of the Niagara Sheet and materials is appreciated. Drafting help with maps was provided by John Walton of Fredonia. Illustrations were prepared by Don Burdick and Ron Warren of the Fredonia Instructional Resource Center.
E.H.M. was wise enough to leave for New Zealand immediately upon hearing of the assignment. R.K.F., having no place to go, has proceeded to reproduce Muller's 1960 Friends of the Pleistocene Field Guide with few improvements and all the controversies and inconsistencies dictated by the western New York geologic record. Some new stops have been added in light of recent local geologic events and RKF's orientation toward processes and predilection for scenery, buried and otherwise. Due to RKF's slowness in producing a manuscript, EHM has had no opportunity to recant or to correct the errors of omission or commission found in the present attempt. We all look forward to EHM's explanations on the outcrops in the fall.

F: GLACIAL GEOLOGY AND BURIED TOPOGRAPHY IN THE VICINITY OF FREDONIA, GOWANDA, AND ZOAR VALLEY, NY

Cross Rt. 60 and continue along the Lake Warren Beach.
Later Warren ridges are to the north (1) and the Lake Whittlesey (2) Ridge to the south. Note Warren strand along U.S. Route 20 in Sheridan (see plate 2f and Plate 1). The surface of this gravel terrace is at 755 feet above sea level. This beach trends east-northeast, rising about 50 ft. in elevation in 45 miles.

Gravel pits are in Lake Whittlesey beaches.
The escarpment ahead and to right (south) which separates the lake plain from the plateau has been called the Portage Escarpment, but it is developed on the Canadaway Formation in this area. The escarpment bears no relationship to the Portage Group, which does not crop out in Chautauqua County. The Canadaway Formation totals about 950 ft. and is dominantly composed of shale. The Laona and Shumla Members, each about 30 ft. thick are dominantly siltstone and somewhat thicker-bedded than the other members. These two siltstone members may account for details of the character of the scarp as developed eastward toward Forestville.
Question : In view of the dominantly shale lithology exposed in this portion of the escarpment, is structural control an adequate explanation of the origin of this scarp? Regional dip is very gentle toward the south. If the topography be truly cuestaform, where are the resistant capping strata responsible for the scarp which is 700 to 1100 ft. high in eastern Chautauqua County?

The road drops into a channel
The road drops into a channel (3) formed either along the ice margin (Gowanda) or the beach ridge.

Whittlesey strand at approach to King Road
Note Whittlesey strand at approach to King Road (Cook Rd. of Forestville 7.5 minute Quadrangle). A shallow borrow pit 0.3 mile southwest off King Rd. in 1957 exposed the following :
3. | Shingle gravel, stratified dipping southeast; dominantly of clastic pebbles; matrix coarse-textured; structure, open. | 10 ft.
2. | Laminated lake silt with thin sand and pebble layers. | 4 ft.
1. | Gravel, coarse, poorly-sorted with numerous erratics and rounded boulders suggesting derivation by wave washing of proglacial sediments. | 4 ft.

For most of the way this road follows the beach ridge.
To the south between the beach and the escarpment lie Gowanda moraine remnants (Plate 2e), kame terrace deposits and ice marginal channels. Plate 2f shows the geography of Lake Whittlesey time.

Cross Erie RR.
This is the original right of way. The railroad completed in the early 1850's ran from Piermont on the Hudson to Dunkirk, avoiding such dens of iniquity as New York and Buffalo.

Look for the spit (4) built by the longshore drift
into the Walnut Creek embayment coming up.

STOP 1. Buried valley of Walnut Creek.
Hanover Center Landslide. Figures Fl and F2 outline the general setting of this stop. A well at the house across the road from the "landslide" bottomed in "quick-sand" at 290 ft. and had to be abandoned because too much sand was pumped with the water. The landslide has appeared to result from groundwater sapping and liquifaction of the units exposed in the base of the amphitheater. Such active processes make for uneasy householders and highway departments.

Bridge over the Silver Creek Gorge.
To the east is the open valley cut in the Walnut Creek valley fill and to the west is the bedrock gorge of Silver Creek which extends most of the way to Lake Erie.

Crossing the filled valley of Walnut Creek
Turn right again (SE) onto Hanover Rd. crossing the filled valley of Walnut Creek. Note the moraine remnants to the south of the road.

Again we are along the Whittlesey beach (6).

Bridge over Cattaraugus Creek
Cross Bridge (5 ton capacity) over Cattaraugus Creek which is flowing over on bedrock part of which is the south wall of the old Allegany Channel (Figure 1-6).

Cross the ancient Allegany valley
In this area you are crossing the ancient Allegany valley (7) which has at least 500 ft. of fill near here.

Spit which extends SE from the island in Lake Whittlesey
Possible side excursion: Southeast on Long House Rd. 0.6 miles to end of road. This is a spit which extends southeastward from the island in Lake Whittlesey (8). Elevation 840+ ft.

Clear Creek
The road crosses Clear Creek and rises onto Four Mile Level (Elevation 800-840+ ft.).

STOP 2. Gernatt Gravel Products Pit.
Figure F3 summarized the relation between Four Mile Level and the land form being quarried for gravel. If Four Mile is Whittlesey, what is this? If this Whittlesey, then what is Four Mile? What agencies can produce such level surfaces?

STOP 3. Wisconsin Stratigraphy
Gowanda State Hospital Section. Stream bluffs, Clear Creek at Route 62, 39, 18. Collins town, Cattaraugus quadrangle, Erie County. (78°55'50"W, 42°29'20"N). Composite section.
Unit | Lithology Thickness
11 | Alluvial gravel; oxidized, many pebbles and cobbles deeply weathered; rounded to sub-rounded; exotic pebbles numerous | 3.3 ft.
10e | Silt, dark olive-gray; stratified, includes fine sand laminae; oxidized and leached | 1.0 ft.
10d | Silt, tan to olive, oxidized but unleached | 1.3 ft.
10c | Fine sand, finely laminated, yellow-brown 1.2 ft.
10b | Clay and silty clay interlaminated with sand and silt; pairs are 0.5 to 0.25 inch thick, finer toward top. Clay-rich layers are unoxidized. | 6.5 ft.
10a | Silt and fine sand, light-to medium-gray; unoxidized, unleached; laminated to medium-bedded; sparsely pebbly towards base | 10.0 ft.
9 | Till, silty matrix, blue-gray, sparsely pebbly with shale and siltstone dominant. Includes sand and silt lenses but is more compact than overlying laminated units. | 4.0 ft.
8 | Stratified sand, silt and sandy gravel; unoxidized | 1.0 ft.
7 | Till, silty matrix, dark blue-gray, compact, sparsely pebbly. Upper contact marked by seep. Includes minor light gray silt partings. | 8.O ft.
6 | Stratified silt, sand and gravel; unoxidized; upper contact transitional, lower contact sharp | 2.0 ft.
5 | Till, silty matrix, dark blue-gray, compact; moderately pebbly with relatively high proportion of exotic pebbles. Faint seep shows better-sorted lens. | 6.0 ft.
4 | Gravel, pebbles and cobbles in coarse sand. Crude imbrication suggests flow to northwest. Pebbles dominantly rounded with diverse lithology. Unit thickens southwest to about 20 ft. at the stream bend. | 3.0 ft.
3 | Till, calcareous throughout; color ranging from olive-brown to orange-brown, suggesting incomplete assimilation of diverse materials. Compact. Sparsely to moderately pebbly. Toward base appears to incorporate and deform under lying stratified sediments. | 20.0 ft.
2 | Silty and carbonaceous clay; stratification disturbed enough to suggest crushing and sliding. One layer contains sparse invertebrate tests and several contain twigs and other plant remains. Wood is more than 38,000 years old (W-866). This unit abuts northward against Unit 3. | 15.0 ft.
1b | Till, pink, silty matrix, (Color 5Y 4/1), fairly pebbly. Surface rises east cutting out part of overlying stratified section. Relationship to Unit 3 not clear as contact is nowhere exposed. Base obscured west of bridge but transitional relationship to underlying is suggested 200 ft. upstream. | 18.0+ ft.
1a | Till, medium blue-gray (5B 5/1), with abundant shanners and flaggy bits of local blue-gray siltstone. Basal contact concealed, but upstream a few hundred yards this unit rests on bedrock. This may be a color phase of the overlying pink till, different only in assimilation of abundant local rock. | 6.0+ ft.
(Note: Sequence of deposition of lower, contorted and disturbed portion of bluff is not certainly established because of discontinuity of exposure and obscured relationships.)
About.8 mile west of highway bridge a well is reported to have penetrated 620 feet of unconsolidated material to about 240 feet above sea level. If correct, this information gives a measure of depth and sharpness of the bedrock valley.

Cross Gowanda moraine,(9) marking recessional position north of the Lake Escarpment moraines.

Begin rise onto proximal slope of massive Lake Escarpment moraine complex (10).

Commence descent into Zoar Valley following Zoar Valley Rd.
CAUTION : This is a long, steep grade. USE LOWER GEAR
Cattaraugus Creek flows across the grain of bedrock topography, crossing bedrock uplands through confined, steep-wall gorges and crossing drift-filled lowlands in broad, mature reaches. One such open reach is Zoar Valley ahead to the southeast, whereas due south at this point, Cattaraugus enters a 3-mile long gorge deeply incised in bedrock. (Figure F4).
Silt and silty-clay till and lacustrine sediments in slumped moraine topography at left. Soil is mapped as Mahoning silty clay loam, steep phase.

Cross Cattaraugus Creek.
Leave interval between cars in crossing wooden bridge (Three ton capacity) (11). Cross mature floodplain.

Pass Girl Scout Camp.
Waterfalls ahead mark the west edge of a drift-filled bedrock valley. Commence climb out of Zoar Valley on steep, winding road.

Crest of a Lake Escarpment moraine.

Turn Right on Forty Rd. to the 2-ton bridge
Turn Right on Forty Rd. to the 2-ton bridge over the South Branch of Cattaraugus Creek. The road climbs out of the valley. More spectacular views are available at STOP F5.
2012: Bridge is gone. This path will take you to the next stop, but by way of a lengthy route to the south, to a different bridge across the South Branch of Cattaraugus Creek.

STOP 4. Enigmatic deposit
If slumping has not obscured the bedding, the source direction and extent of the beds should clearly reveal the nature of this deposit. Should the relationships be somewhat vague, an attempt will be made to make them perfectly clear. There will be complete cooperation with no attempts to stonewall the investigators.

STOP 5. Zoar Gorge Lookout.
The view point about 200 meters from the parking space is on a knife edge meander core well above the valley floor. There are friendly trees for those who prefer something to hold on to.

STOP 6. East valley wall of the ancient Allegany valley.
The small tributary which has filled the Gowanda water supply reservoir to spillway level leaves the broad valley at the cam on the west to enter a deep, entrenched, meandering channel in bedrock on the east side of the road. From this bedrock channel it emerges into Cattaraugus Creek.
Brave souls may visit the meander core via a knife edge (without trees this time) or may peer into the broadening valley of Cattaraugus Creek and observe immediately below in the face of the cliff the diagonal line of the contact of fill and bedrock which is shown in Figure F5.

Turn Right on Broadway into Gowanda
Turn Right on Broadway into Gowanda, astride Cattaraugus Creek in Erie and Cattaraugus Counties. Gowanda in the Seneca langauge means "a beautiful valley between hills". The Seneca Nation of Indians maintains its business office in downtown Gowanda, but the reservation is north of town, extending along Cattaraugus Creek to Lake Erie.
Cattaraugus in the Seneca language means "odorous waters", an epithet given new meaning by the white man's tannery and glue factory on the southern outskirts of Gowanda. Cattaraugus Creek is the largest creek in New York west of the Genesee River to flow north across the Lake Escarpment Valley Heads moraines. In so doing, it has inherited the valley of the Ancestral Allegheny River where it descended from the plateau in a constricted gorge. Bedrock exposures on opposite sides of the valley at Gowanda are only 0.7 mile apart, yet a municipal well is reported to have penetrated 320 feet of drift. (Note: Well probably not on axis of valley as 7-800 ft. is reported elsewhere.)

G: A SELECTED MIDDLE DEVONIAN (HAMILTON) FOSSIL LOCALITY
BIOSTRATIGRAPHY AND PALEOECOLOGY OF THE WINDOM SHALE MEMBER (MOSCOW FORMATION) IN ERIE COUNTY, NY.
Carlton E. Brett
The exposures of Hamilton strata along Lake Erie shore and in various creek beds in Erie County south of Buffalo are among the best-known and most thoroughly-studied Middle Devonian fossiliferous sequences in the world. The monumental studies of James Hall and A. W. Grabau (1898, 1899) provided a solid back•ground for numerous later studies. Yet, in over a century of study, many biostratigraphic and paleoecological problems remain uninvestigated.
Recently, an exceptionally large and complete section of the Windom Shale (Moscow Formation) has been exposed in the shale quarries of Penn Dixie Cement Co. near Bayview, N.Y, This outcrop provides an excellent opportunity for detailed study of the fossil horizons of this upper Hamilton unit. Discovery of several new and little-known horizons at this quarry have led to the present restudy of biostratigraphy of the Windom in Erie County.

G: A SELECTED MIDDLE DEVONIAN (HAMILTON) FOSSIL LOCALITY

STOP 1. Penn Dixie Quarry, Buffalo Southeast quadrangle
The reference section that has been selected for this quadrangle is a large shale quarry (formaiy owned by Penn Dixie Cement Co. of Woodlawn) north of Big Tree Rd. just west of the Erie-Lackawana tracks in the Town of Hamburg. The main access road to this quarry is located near the corner of Big Tree Rd. and Bayview Rd. This road divides the quarry -- actually a large shale pit -- into east and west sides. The west side is older and has not been used for several years consequently it is highly weathered and is beginning to grow in with grass in a few spots. It is still owned by Penn Dixie Co. although this company is out of business in Buffalo. The east side is somewhat larger, is floored almost entirely by grey Windom Shale (Moscow Formation), and was actively used up to 1970 as a source of landfill. Presently it is owned by Sipprell Bros. Real Estate, Hamburg.
1A. East Side of Quarry -Upper Windom
The south side of the quarry forms a slight bank (8-10 ft. high). In places the uppermost Windom beds and the overlying Genundewa-West River are exposed. There is no Genesee black shale nor any Penn Yan-exposed here. Rather, the Genundewa Limestone is in direct contact with the "Conodont bed".
The Conodont bed is a coarse-weathering, dark-grey (weathering yellowish-buff) limestone. Fish plates, teeth, and mandibles are very common in this limestone as are conodonts. This bed which is equivalent to the North Evans of Wells (in Rickard, 1964) yields abundant conodonts and bone fragments when digested with diluted acetic acid. Worn, broken valves of brachiopods (Ambocoelia praeumbona, Atrypa reticularis, and Mucrospirifer mucronatus) also occur in this bed, apparently derived from the underlying limestone.
The uppermost Windom is a calcareous, concretionary layer about one foot thick, weathering light-yellowish, but light-grey when fresh, and containing fossils (Ambocoelia praeumbona, Phacops, Mucrospirifer) which are quite abundant in spots. Directly above this (in some places) is a thin (1-2 in.) layer of argillaceous limestone. It occurs on the underside of the Conodont limestone and is partly or entirely incorporated into the North Evans. Angular slabs as well as rounded pebbles, can be seen "floating" in the crinoidal bone-bed matrix of the latter. It appears brecciated and the fragments have cracks in them which are "squeezed" full of crinoidal matrix. Some greenish stains on the concretionary bed resemble glauconite.
The upper Windom is shaley below the uppermost concretionary layer for about 3 ft. and is "barren" of fossils. The "Praeumbona bed", a calcareous, slightly concretionary interval about l.5 ft. thick caps the small knob in the southwest corner of the east side of the quarry. Abundant Ambocoelia praeumbona (in patches) as well as Atrypa, Athyris, Devonochocnetes, auloporid corals and large trilobites (Phacops) occur in this unit. Below this is a shale interval some 5 ft. thick extending down to the next thin calcareous bands. This interval contains pyritized fossils and a fauna similar to that of the Ledyard shale (Fisher 1951). Pyrite nodules also occur here, but they are almost always small twig-like bodies unlike the large nodules found at Alden. The most abundant fossils here are Nuculites, tiny Tropidoleptus and Ambocoelia, the ammonoid Tornoceras uniangulare, nautiloid fragments and the gastropod Mourtonia. Rarer items include coiled Greenops and wood fragments. At present, this undescribed occurrence of pyritized fossils is under study.
The remainder of the middle Windom which covers most of the quarry floor is barren of fossils down to the lower 3-4 ft. Three thin calcareous shale bands about 2 in. thick are exposed just below the pyrite zone and represents distinct traceable horizons (no fossils).
1B. Tichenor limestone and coral-trilobite beds
In the northeast corner of the quarry, mounds of bulldozed shale have been left. These mark the position of the fossiliferous lower Windom. Here the contact between the Windom and the Tichenor limestone is exposed in a few spots due to the occurrence of small swells which dome the Tichenor up 5-6 ft. (in maximum relief) above its normal position. (The cause of this structural feature is unexplained; such features are rare in western New York). The upper surface of the limestone has a very rusty appearance due to large amounts of pyrite. Fossils in the Tichenor, of which Spinocyrtla and crinoid predominate, are somewhat abraded. There are not as many Favosites or other corals as elsewhere. The upper surface of the Tichenor limestone appears to have been subjected to erosion prior to Windom deposition. There are pockets in the surface of the Tichenor which are filled with soft, grey shale (Windom). The lowest beds of the Windom here are very soft, friable, grey shales containing Ambocoelia (though not in great abundance as at Eighteenmile Creek). These occupy the lower foot of the Windom.
The coral layer fauna of the Spinatrypa bed is well-developed at this locality, though not as rich in Heliophyllum or Cytiphylloides as that of Eighteenmile Creek. In 1970 when bulldozers were still working in this area, it was possible to collect literally bushels of excellently preserved Cystiphylloides, Heterophrentis, Atrypa, Spinatrypa, and Mediospirifer from this bed. Rhipidomella, Douvillina, Megastrophia and rarely Elytha are also found in this layer. The total thickness of this layer is probably only about 3-5 in.
Some 2 ft. up from the Tichenor limestone the shale becomes calcareous. These harder layers stand out in several spots surrounding the Tichenor "domes". This is the coral-trilobite horizon characterized by a low diversity fauna made up chiefly of trilobites and rugose corals. Phacops predominates here and occurs most frequently as somewhat distorted, coiled individuals when complete. Flat specimens can also be obtained though more rarely and occasionally they are found in clusters. I collected here a single slab with 11 complete individuals of Phacops rana. Greenops and Dechenella are also rarely found. Brachiopods are much reduced in this horizon, but Atrypa, Rhipodemella, Athyris and Mucrospirifer consobrinus are present. Trace fossils are particularly prevalent at this horizon, the surfaces of otherwise barren slabs show long sinuous "trails" of limonite suggesting worm or gastropod tracks. Typically, the lower beds are packed with rugose corals, but like the trilobites, their distribution tends to be patchy. Traces of nautiloids (Spyroceras, "Orthoceras") are fairly common and I have collected a very faint trace of a large goniatite here. The area around the outcropping edges of the "Trilobite-beds" are considerably worked by collectors who have made extensive "pits" and debris piles. These calcareous layers are about one foot thick and grade into barren middle Windom seen in section 1A.

H: GEOLOGY AND OCCURRENCE OF OIL AND GAS IN CHAUTAUQUA COUNTY, NEW YORK
Arthur M. Van Tyne
Senior Geologist-in-Charge
Oil and Gas Office, Geological Survey
New York State Museum and Science Service
Alfred, New York
HISTORY-SHALE GAS DRILLING
The first natUral gas well completed in New York State, and the United States, was drilled at Fredonia in 1821 to a depth of 70 feet. The owner and driller of the well, William A. Hart, was the first man to market natural gas in the United States and, through his efforts, Fredonia became the first community in the United States to be lighted by natural gas. During his visit to the village in June of 1825 General Lafayette is said to have been delighted by the gas light illumination. The well produced gas in declining volume for a number of years but no enlargement of service was possible. Therefore, in order to secure a new supply of gas, Mr. Preston Barmore drilled a new gas well during the year 1858. The well was located about one mile northwest of the Hart well and consisted of a dug cavity about 30 feet deep in the bottom of which two holes were drilled to depths of 100 and 150 feet. In the fall of 1858 Mr. Barmore, together with Elias Forbes, formed the Fredonia Gas Light Company and commenced supplying gas to the village. The first deep well was drilled by Alvah Colburn in 1871 at his mill located south of Main Street. The well which was drilled to a depth of 1,256 feet encountered gas between 130 to 300 feet, and reached the Onondaga limestone at 1,079 feet. A concerted effort to find more gas was initiated and it is estimated that 300 shale gas wells were drilled in Chautauqua County towards that end.
Medina Drilling
During the autumn of 1886, and the first half of 1887, the first Medina Sandstone well in the county was drilled about one-half mile southeast of the village by the Fredonia Gas and Fuel Company. This well reached a total depth of a little over 2,500 feet and obtained production of about 7,000 cubic feet of gas per day, with a maximum pressure of 160 pounds, from the Medina. Additional Medina drilling did not take place until 1903 when the South Shore Gas Company and the Brocton Gas Company began to drill Medina wells in the Brocton and Silver Springs areas. This development was probably spurred by successful Medina drilling to the north in Erie County around the turn of the century. Since 1903, drilling in Chautauqua County has continued on a sporadic basis with the majority of wells being drilled for Medina sandstone gas production. It appears that the present spurt in Medina drilling, commenced in 1973, will surpass all previous periods of drilling in the total number of wells drilled. It is estimated that about 700 Medina wells have been drilled to date in Chautauqua County.
Deep Drilling
The first of ten deep wells drilled in Chautauqua County was the Cassity #1 of Frost Gas located one-half mile east of Dunkirk. This well was originally drilled to a depth of 2,052 feet in 1908 and was re-entered and drilled deeper in 1916. The well topped the Trenton at 4,010 feet and was stopped at 4,035 feet. The Niehaus well, located two and one-half miles northeast of Dunkirk, was also an old well which was drilled deeper to 4,517 feet. The drilling was stopped in 1949 after encountering a good show of gas and considerable salt water in the Cambrian Theresa (Galway) Sandstone.
Since then, eight more deep wells have been completed all ending in Cambrian sandstones except one which stopped in the Trenton. No well has been drilled to basement rocks in Chautauqua County, but the deepest well in the county, the Harrington #1 of Wolf's Head Oil, located six miles northwest of Jamestown and one-quarter mile east of Ellery, was completed at 7,694 feet in the Cambrian Potsdam Sandstone which overlies basement rocks. Two of the deep wells had good shows of gas from Cambrian sandstones, but no commercial gas or oil production has so far been found in the Cambro-Ordovician rocks of Chautauqua County.
2012: No field trip present.

GUIDEBOOK
to
FIELD EXCURSIONS
conducted at the
47th MEETING
of the
October 3l-November 2, 1975
Hanfred P. Wolff, Editor
Host
Hofstra University
Hempstead, New York
ACKNOWLEDGEMENTS
This guidebook provides a permanent record of the 47th meeting of the New York State Geological Association. The papers and road logs are presented to enhance the various field trips, to allow participants to read through them at their leisure. and to later make a return visit whenever they desire. For the most part they summarize previous information and/or provide new data and concepts that reflect continuing research in the New York City-Long Island-New Jersey region.
The trips vary from bedrock geology and stratigraphy to coastal and glacial geomorphology -to excursions of areas containing earth, energy, and environmental resources -to ocean voyages. Because of time implications some trips (particularly on Long Island) cannot later be completed in the exact manner described herein. The interplay between man-made and geological influences will continue to alter these areas, for better or worse, and whenever possible, modern management techniques and environmental considerations have also been included.
The shortness of available time for preparing the guidebook has not given the authors an opportunity to see proofs of their articles, and the editor accepts any responsibility for errors that may appear. Editorial changes were kept minimal in most instances. Special acknowledgement is made to the many authors from neighboring institutions without whose help this guidebook and meeting would not have been possible. The effort can only be appreciated by those who have made similar contributions to this meeting over the years.
For individual efforts in organizing the format of the guidebook and logistics for the meeting, special thanks to Dr. Kurt E. Lowe, Professor Emeritus at City College of the City University of New York. Dr. Lowe has long been a prominent figure in the association and consented to be our guest lecturer for the banquet at this meeting.
For her assistance in preparing the guidebook, and making all the detailed arrangements for transport, food and lodging, special thanks and appreciation also go to Mrs. Margaret L. Johnson, the Geology Department secretary who took it upon herself to gather the information for organizing the field excursions.
The editor would also like to thank Ms. Christine Anderson (President), and the other geology majors and members of the Long Island Geological Society (Hofstra's Geology Club) who contributed their time and effort toward making this a successful meeting, and Dr. Usman A. Sayeed for drafting the guidebook cover.
Manfred P. Wolff Editor and President, 1975

A1: STRATIGRAPHY, STRUCTURE AND PETROLOGY
OF THE NEW YORK CITY GROUP
Simon Schaffel
Department of Earth and Planetary Sciences
City College of C.U.N.Y.

A1: STRATIGRAPHY, STRUCTURE AND PETROLOGY
OF THE NEW YORK CITY GROUP

Terminal moraine
Terminal moraine occurs directly to the right (north). The moraine is either the Ronkonkoma capped by the Harbor Hill or an undifferentiated mixture of both.

Terminal moraine, Port Washington delta
Terminal moraine on left (south) with Port Washington delta
on right (north). The latter feature formed as a result of a periglacial lake forming behind moraine and fronting the ice.

Pass onto top of moraine.
Pass onto top of moraine. Typical glacial knob and kettle,
hummocky-type topography.

Pass through valley of Little Neck Bay
Pass through valley of Little Neck Bay, which lies north-south of the expressway. This valley, although covered with a veneer of glacial till represents an initial preglacial valley. It is one of several north-south trending valleys which occur along the north shore of Long Island and undoubtedly represent obsequent valleys to the subsequent valley occupied by Long Island Sound.

Continuous exposures on both sides of expressway.
Lithology composed of mica schists with subordinate amounts of sillimanite schists and biotite-quartz gneisses. Minor folds common exhibiting chevron pattern. Fold axes and other linear elements plunge northward (15 - 50¬∞). These units have been designated as "undifferentiated schists and gneisses" on the 1961 edition of the New York State Geological Map. Hall (1968b) referred to them as Hartland-Manhattan undivided. Seyfert and Leveson (1969) placed them in their own coined "Hutchinson River Group."

Bronx River valley.
Boundary between the eastern undifferentiated schists and gneisses and the New York City Group to the west. Boundary is believed to be a major stratigraphic-structural break.

Continuous exposure of Manhattan schist
Continuous exposure of Manhattan schist on both sides of expressway forming Crotona Park synclinal ridge.

Cross Park-Webster Avenue valley.
The valley is underlain by Inwood marble. This north-south low is the former valley of the Bronx River. The stream was evicted from its original course further north into its present valley.

Anticline of amphibolite member of Manhattan schist
Anticline of amphibolite member of Manhattan schist immediately to right. This unit is approximately 20-30 feet thick and about 50-60 feet above the Inwood-Manhattan contact.

STOP 1. GRAND CONCOURSE SYNCLINAL RIDGE
Manhattan schist occurs along the north-south trending Grand Concourse forming a ridge while the lesser resistant Inwood marble forms the valleys on both sides of the ridge. Manhattan schist-Inwood marble contact is present along south side (east bound lane) of Cross-Bronx Expressway. Typical interbedding of Inwood and Manhattan along west ridge slope can be seen.
Inwood marble is a gray to buff-colored, medium to coarse textured marble and dolomitic marble. Bed thickness varies from 1/2" to 6 feet. Minor amounts of graphite, pyrite, phlogopite, tremolite and diopside have been found. Thickness of the formation varies but here it occupies the entire Jerome Avenue valley - approximately 1000 feet. Repetition of beds by folding is possible.

Continuous exposure on south and north side of expressway.
FORDHAM GNEISS forming Highbridge prong of Fordham ridge. This ridge is one of the type localities for the Fordham in New York City. The ridge is an overturned anticline to the west.
Lithologically the unit is a biotite-feldspar-quartz gneiss. The three minerals form alternating bands which vary from inches to three feet. Band is very uniform and consistent. Plagioclase feldspar is common but subordinate to the potash feldspar. Intercalated bands of granite pegmatites, amphibolites, and marbles occur. Bands (layers) are steeply dipping (60-90°) to the east. Small minor folds are common. Larger isoclinal and asymmetrical folds can be detected with axial planes overturned toward the west. All fold axes plus other linear elements plunge south at approximately 15°.

Cross Harlem River, separating Manhattan and Bronx.
The Harlem is not a river but a strait. The entire valley is underlain by steeply dipping, tightly folded beds of Inwood marble.

STOP 2. BASE OF COOGAN'S BLUFF
Carefully cross the highway to base of cliff and walk north to fresh exposure of Manhattan schist. Amphibolite (Hornblende schist), and Pegmatites.
Merrill et al. (1902) cites this as a type locality for the Manhattan schist. The principal lithology is a coarse textured light to dark-grey biotite muscovite quartz schist with sporadic high concentrations of garnet. Other minor minerals in order of abundance include plagioclase (oligoclase), potash feldspar (orthoclase), magnetite, pyrite, and sillimanite. Pods (augens) of quartz and feldspar, where quantitatively significant, may develop a gneissoid appearance. Axes of minor and major folds within the schist as well as other linear elements plunge south about 15°.
The Amphibolite (Hornblende schist) here is a dark grey to black medium texture rock. Principal minerals include hornblende and plagioclase (andesine) feldspar with local high concentrations of epidote. A rhombohedral-type jointing is the result of the dense and close parallel arrangement of the prismatic shaped hornblende crystals. This jointing contrasts with the block type peculiar to the Manhattan schist and Fordham gneiss. The Amphibolite bed here is approximately 30-60 feet from the Manhattan-Inwood contact and is believed to he the same bed viewed at Mile 26.2 earlier. This Amphibolite appears to be an excellent horizon marker for locating the Manhattan-Inwood contact in the region.
The "Pegmatites" found in the New York City Group are composed of granites, granite pegmatites, graphic granites, aplites, and quartz veins. These concordant and discordant bodies occur in all formations with varying widths up to 10 feet. Quartz, pink microcline feldspar, greenish oligoclase plus muscovite are the common principal minerals. Biotite, hornblende, magnetite, garnet, black tourmaline are some of the minor constituents.

Dyckman Street fault.
One of the few cross faults found in New York City resulting in an east-west cross valley.

STOP 3. INWOOD PARK-ISHAM PARK
Proceed west into Inwood Park. The canoe-shaped valley underlain by Inwood marble is an anticline while the two adjacent Manhattan schist ridges are synclines (Figure 3). Amphibolite exposure occurs along the path leading to the western ridge. Spuyten Duyvil, the water body immediately to the north is at present a strait connecting the Hudson River (an estuary) with the Harlem River (a strait). Prior to being modified by glaciation and subsequently by man, a true stream flowed here controlled by the existing lithology and structure. A fuller discussion will be presented.

Isham Park
The marble here and in this area is the type locality named after the village of Inwood. The marble is gray to buff-colored medium to coarse textured marble and dolomitic marble. Essentially the same lithology as the Inwood found at Stop 1. Graphite, pyrite, phlogopite, tremolite and diopside (malacolite) may be found here and elsewhere in the neighborhood. Quartzite, interbedded with the marble, indicates original sandy beds. These quartzite layers plus aplites often occur as disconnected boudins. An occasional thin schistose layer suggests original mud or limey mud sedimentation. Folding and plastic deformation are present. Possibly the only example of a residual soil in New York City is present at this stop.

STOP 4. DI RIENZO STONE QUARRY
Yonkers granite gneiss.
Please be careful in this quarry. Do not collect any specimens from the trimmed and stacked rocks. These are the finished products of this quarry and the labor of those who work here.
Merrill et al. (1902) states that the Yonkers is "technically a gneissoid granite." The rock is composed of quartz and microcline feldspar with lesser amounts of orthoclase. The feldspars are responsible for the striking pink-red color. Although not obvious, foliation caused by the presence of biotite, is present. The biotite occurs as clumps, which are usually discoidal but occasionally spindle shaped. When the latter phenomenon occurs a lineation is also present. The foliation here is at a high angle (vertical) and is normal to the close-spaced horizontal sheeting. Minor amounts of hornblende, apatite, and zircon are also found. A single amphibolite layer occurs in the quarry. The Yonkers is invariably associated with the Fordham and almost without exception occurs as central masses surrounded by the Fordham. Contacts between both are sharply defined and gradational.

STOP 5. FORDHAM GNEISS
Almost 1000 feet of Fordham is exposed on both sides of the highway. The Fordham here exhibits great variation and the lithologic divisions of this formation as advanced by Hall (1968a. 1968b) is appropriate.

Inwood marble - Manhattan schist contact
The service road follows the contact between the Inwood marble which underlies the valley to the west and the Manhattan schist which forms the ridge on the right (east). Exposures of the Manhattan can be seen periodically.

STOP 6. FORDHAM GNEISS
Three subdivisions of the Fordham were tentatively identified by Hall (1968a) at this site. The Fordham body occurs as a northward plunging anticline. Sprain Lake valley immediately to the east contains Inwood marble. Numerous exposures of the marble are found along the east side of the valley paralleling the parkway.

Manhattan schist in a north plunging anticline
The ridge Which we cross between Sprain Lake valley and NY 100 to the east is underlain by Manhattan schist which forms a north plunging anticline.

STOP 7. MANHATTAN SCHIST
Manhattan schist plus Amphibolite layer near contact with Inwood marble in valley of NY 100.
Continuous exposures of Manhattan schist on west side of road.

Exposure of Inwood marble on east side of road.

Core of Yonker granite occupying center of hill.

Continuous outcrop of Yonkers granite on crest of hill.

Fordham gneiss outcrops occupying side of hill.

STOP 8. HARRISON DIORITE
Merrill et al. (1902) lists quartz, hornblende. feldspar and biotite as the principal constituents in this unit. Feldspar includes orthoclase and plagioclase (oligoclase-andesine). An igneous origin is indicated for the unit. Merrill further suggests that the Ravenswood granodiorite found in Queens County to the south may be a correlative equivalent.

STOP 9. EASTERN UNDIFFERENTIATED SEQUENCE
Intersection of NY 125 South and US 1. Park in bank parking lot. Freshly exposed schist along rear of parking lot. The unit here is part of the larger area of undifferentiated schists and gneisses first mentioned at Mile 23.6 on the Cross-Bronx Expressway.

A2: STRUCTURE AND FORM OF THE TRIASSIC BASALTS IN NORTH CENTRAL NEW JERSEY
Michael Sichko Jr.
Nassau Community College
The structure and form of the Triassic basalts in north central New Jersey is exposed in the First, Second, and Third Watchung Mountains, and the Palisades Sill. The First, Second, and Third Watchung Mountains are tholeiitic basalt flows that are topographically prominent ridges in northern New Jersey (Fig. 1). They strike N 40° E and have a gentle dip of approximately 17° NW. Their northeastern and southwestern sections exhibit curved terminations, thus giving the ridge system a synclinal trough appearance. They are also terminated in the northwest by a border fault that separates the Triassic basin from the Pre-Cambrian gneisses that lie to the northwest. The three extrusive sheets are interbedded with Triassic sedimentary rocks (shales, sandstones, and argillites) of the Newark Group. The extrusion of the successive lava flows took place at the time of deposition of the Newark Group (Lewis, 1908).
The Palisades Sill is emplaced in a structural and stratigraphic basin called a taphrogeosyncline by Kaye (1951). It has intruded the Newark Group and where it has concordant contacts the intrusion has a general strike of N 30 0 E., and dips between 10° and 15° NW (Walker, 1969). The Palisades Sill also has satellite intrusions above it, such as the small laccolith or sill at Granton Quarry. The Palisades Sill is probably in part concordant and in part discordant (Thompson, 1959, Lowe, 1959).
The Palisadian Igneous Province
The igneous rocks and their counterparts in the other Triassic basins record the emplacement of basic magma on an enormous scale, 1,000 miles in length and about 200 miles wide. Significantly they correlate broadly with the vast Karoo dolerites and equivalent basic rocks in the Southern Hemisphere, and like them, apparently were emplaced during an episode of tension attending the widening of the Atlantic basin (Van Houten, 1969).

A2: STRUCTURE AND FORM OF THE TRIASSIC BASALTS IN NORTH CENTRAL NEW JERSEY

STOP 1. Granton laccolith or sill
In this exposure a satellite intrusion from the Palisades Sill, the Granton sill or laccolith, can be observed. The Granton sill has intruded the Lockatong formation of the Newark Group. In the easterly section of this exposure small appendages of the sill exhibit intrusive contacts with the shales and sandstones of the Lockatong formation. At the contacts the chilled diabase has an intersertal - intergranular texture, away from the contacts the diabase has an intergranular texture. The whole outcrop dips to the west at a gentle 15° to 17°. Fossils have been found in the black shale layers , they include fish remains of coelacanths, Diplurus longicaudatus, Diplurus newarki and the common branchiopod Estheria ovata (Schuberth, 1968).

STOP 2. Basal contact of the Palisades Sill and the Mg-Olivine Layer.
Below the basal contact of the Palisades Sill a small stream has eroded through the Stockton formation which consists of arkosic sandstone and black and green shales. The alternating sandstone and shale beds attest to the changing environmental conditions during the deposition of the Stockton formation. Continuing up the trolley track right of way the concordant basal contact between the Palisades Sill and the arkosic sandstone of the Stockton formation can be observed. The contact metamorphic zone at this outcrop can be observed by noting that the shale has been metamorphosed into a hornfels and the sandstone has developed quartzitic characteristics. Columnar jointing has developed perpendicular to the basal contact at this outcrop. Further up the right of way a xenolith of shale plucked from the floor of the intrusion can be seen near the basal chilled zone. At the bend in the trolley route the Mg-Olivine layer comes into full view. The base of this layer is approximately 40 feet above the chilled diabase. The layer outcrops as a highly weathered zone due to differential weathering of the cliff face. It is believed that the Mg-Olivine layer formed at the junction between two magma phases (Walker, 1969). Columnar jointing is pronounced directly above this layer.

STOP 3. Upper contact of the Palisades Sill.
This exposure of the upper contact of the Palisades sill is concordant with the rocks of the Stockton formation (Fig. 4). The chilled diabase is fine-grained here as compared to the course-grained diabase to the east of this outcrop. Although the metamorphism is less pronounced at the upper contact than the lower contact the shale has been metamorphosed into a hornfels and the sandstone has developed quartzitic characteristics. Both the contact and strata dip gently to the west.

STOP 4: Pillow lava of 1st Watchung Lava.
The pillow lava of the 1st Watchung Mountain at this exposure represents the uppermost flow unit of a two unit system (Van Houten, 1969). Nichols (1936) defines a "flow unit" as a tongue shaped structure within a flow. The individual pillows are somewhat ellipsoidal in outline and have long dimensions of approximately 0.5 meters in length (Fig. 5). Adjacent pillows have adjusted their shape to fit together quite well. Some individual pillows exhibit vesicularity and radial jointing. The pillows lie in a matrix of tuffaceous material and weathered basalt. It appears that pillow lavas must generally form by a combination of the process of bulbous budding underwater and by the generation of an emulsion (Lewis, 1915; Fuller, 1940) in which the disperse phase consists of rounded "drops" of fluid lava and the disperse medium is water, very watery sediment, or water-saturated hyaloclastic debris. (MacDonald, 1967).

STOP 5A: Upper Surface of 1st Watchung Lava Flow
The Garret Mountain overlook allows for a spectacular view of the Triassic Lowlands of northern New Jersey. From this vantage point the more resistant Watchung lava flows are seen topographically as ridges. To the northeast beyond the Paterson water gap, which is occupied by the Passaic River, the 1st Watchung flow is easily observed. To the northwest the 2nd Watchung mountain can be seen. On the walkway at the overlook evidence for glacial movement in this area is in the form of glacial polish, striations and erratics. The hackly appearance of the unglaciated portions of the lava flow are due to the differential weathering of the tops of columns which comprise a major section of the lower flow unit of the 1st Watchung mountain.

STOP 5B: Lower Contact of the 1st Watchung Mountain.
At this exposure the lower chilled contact of the 1st Watchung mountain lies directly over the red shales and sandstones of the Brunswick formation. In this lower flow unit, the chilled zone is highly vesicular, above this zone the colonnade and entablature are clearly visible. In the talus slope below this outcrop representative samples of each zone of the basaltic lava flow can be found.

STOP 6: Lower part of the 1st Watchung mountain
In this exposure of the lower part of the 1st Watchung mountain one encounters a well-developed lower colonnade zone and a curvi-columnar zone with markedly radiating slender joints (Manspeizer, 1969).

A3: PLACER MINING AND MINERAL BENEFICIATION OF ILMENITE SAND DEPOSITS NEAR LAKEHURST, N.J.
Harold F. Roellig, Adelphi University
Dennis Radcliffe, Hofstra University
Ilmenite (FeTiO3) is used mainly in the production of white titanium dioxide. Because of its whiteness, high refractive index and resulting light scattering ability, synthetic titanium dioxide is unequaled as a non-toxic white pigment for paints, paper, rubber, dyes and ceramics.
Ilmenite and rutile (TiO2) are used in the production of titanium metal. Titanium is one of the space age metals. One hundred years ago it was considered a vexing contaminant in magnetite deposits that often rendered the iron ore worthless. Today titanium is in demand as an alloy of aluminum to strengthen the skins of supersonic aircraft so that they can withstand the high temperatures generated by air friction. It is also used as a refractory alloy to withstand the intense heat of jet engines and rockets.
Titanium pigments were made originally by dissolving ilmenite in sulfuric acid, crystallizing to separate iron, then hydrolyzing the solution and calcining the precipitate. Newer plants utilize the Kroll process whereby titanium tetrachloride is produced in fluidized bed chlorinators. The tetrachloride is then either oxidized to the white dioxide pigment or is reacted with magnesium under an inert atmosphere to produce titanium metal.
Although titanium is the ninth most abundant element in the earth's crust, it seldom is found in concentrations rich enough to be used as an ore. Thus, natural concentration processes especially placer formation are required to form a significant ore body. The mining of ilmenite in New Jersey by Asarco, formerly the American Smelting and Refining Company, occurs in such placer deposits.
The ilmenite concentrates generated at this operation are sold under a 10 year contract to E.I. du Pont de Nemours and Co. for manufacture of pigments.
Ore reserves are approximately 15O million tons assaying 1.951 total included TiO2. The production rate is 185,000 tpy (tons per year) of ilmenite concentrates or about 20% of total U. S. production. At this mining rate ore reserves should last about 20 years.

ASARCO Manchester Plant
Turn into Asarco private road and drive South to the parking lot.
2013: The operation was expected to have a 20- to 22-year life from 1973 when production began, based on a planned initial rate of 155,000 tons and a possible ultimate rate of 185,000 tpy of ilmenite, averaging 63% TiO2. All ilmenite produced was under a sales contract to Du Pont. The mine was closed in March 1982 because of escalating costs and the prospect of long-term oversupply situation.
From: NRC Briefing with Manchester township, NJ to discuss Heritage Minerals, Inc., Lakehurst, NJ
Within this area, NRC licenses about 695 cubic yards of monazite-rich sands, because it is source material. Source material contains greater than .05% by weight of thorium and or uranium in any chemical or physical form. The physical form at heritage is monazite.
History of Facility
From 1971 until 1982 sands containing economically interesting components as well as small concentrations of uranium and thorium were dredged from about 50 to 70 feet below the site by ASARCO, the original owner.
Beginning in 1987, Heritage Minerals processed the stockpiled sands which were left behind as tailings from the previous mining operation. The sands were processed by physical means to separate the zircon and leucoxene (titanium oxide). In 1989, NRC found that heritage was producing a waste stream that met the definition of source material and directed heritage to apply for an NRC license. Heritage applied for the license and it was issued in January 1991.

A4: SHINNECOCK FLOOD TIDAL DELTA AND COASTAL STABILIZATION PROBLEMS WEST OF SHINNECOCK INLET
Larry McCormick
Southampton College
The shoreline along the south side of eastern Long Island changes regularly in character along an east-west traverse. From Montauk Point to Napeague Harbor it is characterized by cliffs up to 60 feet high overlooking narrow cobble beaches. A relatively short segment of the shore between Napeague Harbor and the village of East Hampton consists of a series of low dune ridges trending roughly parallel to the present water line. From East Hampton to Southampton Village is a sandy beach bordered landward by a single narrow dune ridge that rests on the truncated margin of a gently sloping outwash plain. Westward from Southampton the beach and dune ridge are separated from the rest of Long Island by a series of shallow bays. At one time this barrier island system was continuous to Fire Island Inlet, but is now interrupted by Shinnecock and Moriches Inlets.
Much of the shore zone from East Hampton westward is densely populated. The construction of numerous dwellings close to the water has caused much attention to be focused on the continual recession of the beaches in this area. This concern has resulted in periodic rather piecemeal beach nourishment programs as, well as construction of grain fields to trap sand from the prevailing westerly littoral drift. Shoreline recession results from both natural processes and from works of man. An understanding of the causes should be helpful in determining where beach stabilization programs are needed, and to some degree, guide the selection of the kind of remedial action necessary.
On this trip stops be visited along the segment of barrier island from Southampton to Moriches Inlet. The stops are designed to emphasize the nature of the problems facing this portion of the barrier island and the actions taken to solve these problems.

STOP 1. is located at the intersection of Halsey Neck Lane and Meadow Lane in the Village of Southampton. This stop is most easily reached via Route 27A which intersects Halsey Neck Lane at the western margin of the Village of Southampton.
This portion of the shoreline has experienced rapid recession over the last four years, and is an interesting locality to examine the buried record of storm events.
The second house to the east is owned by Nelson Levings and was located immediately behind the partially destroyed bulkheading that now extends out onto the beach. The house was moved during the winter of 1971 to avoid destruction. This occurred only two years after the construction of the protective bulkheading. Slightly further east is the beach pavilion of Southampton Town, now perched at the edge of the dune line. To the west several large mansions are now-dangerously close to the front of the dune line.
During the fall of 1972 a rather unique protective device was installed in front of the large pinkish buff home located nearest the dune line to the west. A trench was excavated in the dune and plasticized bags of woven nylon were pumped full of beach sand. The filled bags were placed in the trench and stacked up to provide a riprap for the dune face. The dune was then reconstructed over the riprap to protect them from vandalism. At the time of this writing they are not exposed but might be visible by the time this field trip is taken.
Excavation of the beach at this point usually exposes thick layers (2-6 inches) of heavy minerals. These thick layers represent storm lag deposits and provide a handy reference of the beach profile under storm conditions. The location of the storm beach is of considerable importance when considering the depth to which bulkheading or riprap is to extend.
These layers are usually local, pinching out quickly along the strike of the beach, but when present are useful indicators of storm conditions.
Thin heavy mineral layers (less than 2 inches) are common and frequently represent a wind lag deposit generated on the beach berm. In Plate lB these berm layers have been truncated by a storm beach that has in its turn been buried by a wedge of light buff colored sand characteristic of rapid beach accretion.
Heavy mineral storm layers may be simple lenses rich in garnet and magnetite or they can exhibit the rather complicated scour and fill structure illustrated in Plate 2A and B. The latter are produced as a wave cut scarp which migrates up the beach face under storm conditions. Waves strike the scarp and scour out a shallow trough carrying off the lighter minerals and leaving behind a thin apron of heavy minerals. As the scarp and trough migrate up the beach the thin aprons of heavies coalesce to form the thick upper heavy mineral layer.
Layers of coarser sediment do not appear to be related to high energy conditions. Size seems to depend more on availability than energy on south shore beaches.

STOP 2. Flood tidal delta at Shinnecock Inlet.
The vehicles will proceed to the Marine Station at Southampton College where trip participants will board a boat for a trip to the tidal delta. The vehicles will then proceed to the west side of Shinnecock Inlet via Ponquogue bridge and wait for participants to return.
INTRODUCTORY STATEMENT
Prior to the first careful surveys of the Shinnecock area in 1838 an inlet existed about two miles east of the present location of Shinnecock Inlet. However, a map of the U. S. Coast and Geodetic Survey shows that it had closed by 1838. From Southampton west to Round Dune the barrier island was unbroken from 1838 until the hurricane of 1938.
During the storm of 1938 a wash-over channel developed and cut rapidly downward to produce a narrow channel that was ultimately deepened, widened and stabilized to form Shinnecock Inlet. Details of the change in the Inlet since 1939 are given in Figure 19 of Taney's publication "Geomorphology of the South Shore of Long Island." That figure is included here for the purpose of completeness. A small revetment was constructed on the west side of the Inlet in 1947, but it was not until 1952 that construction on the presently existing jetties was begun. Dredging of the channel before and after jetty construction has been carried on intermittently.
In 1938, when the Inlet was opened, some sand was carried inside the Inlet and deposited by the storm surge. Tidal currents sweeping in and out have added to that original sand mass and modified it to create the vast flood tidal delta that exists today. Similarly, sand being carried by the longshore currents was swept seaward to form a large asymmetric ebb tidal delta. The historical development of these deltas and the distribution of sediment on them is the subject of this stop.

STOP 3 is reached by proceeding westward on dune road from Shinnecock Inlet. Travel 1.1 miles west of the Inlet and stop on the newly paved section of Dune Road.
This is the site of a major storm wash-over created during the storm of February 18. 1972. The actual wash-over channel has been dammed with two parallel mounds of artificial fill and the road, destroyed during that wash-over, has been repaved. A small wash-over fan extends to the north of the road. The dune ridge normally present along the barrier island is non-existent at this point.
This weakened segment of the barrier island provides an excellent setting to discuss the dynamic nature of the barrier island system on eastern Long Island and causes of that dynamism. All of the basic elements that make up the barrier system are present at this spot or are visible nearby. The beach face, berm, wash-over channel and wash-over fan are present and dune ridges are visible a short distance to the east and west.

STOP 4 is located 11.0 miles west of Shinnecock Inlet on Dune Road. Any point along the road that allows access to the beach will satisfy the requirements for this stop.
The purpose of this stop is twofold: First to observe the solution that has been adopted to stem the problem of shoreline recession, and second, to allow participants an opportunity to contrast the condition of this protected segment of the barrier island with the unprotected portion downdrift of the last groin (STOP 85).
The groin field observed at this location was constructed under the authorization of the 1960 River and Harbor Act for the area from Fire Island Inlet to Montauk Point. The 1960 Act provided for the establishment of a continuous dune line to defend against flooding from storm surge and the establishment of sand bypass plants at Shinnecock and Moriches Inlets. In addition, provision was made for the construction of several groins and for a beach nourishment program. The federal government assumes the major share of the expense in construction of these groins in view of the broad protection that the hurricane protection portion of this program implies (approximately 70% federal funds). The level of federal funding is much reduced for erosion control (approximately 30% federal funds). The author is on public record as criticizing the 1960 plan for acting as an umbrella for local beachfront owners to obtain a high percentage of federal funding for what is essentially erosion control.
The piecemeal enactment of the 1960 plan which included groins almost as an afterthought, is brought about by the necessity for state and local authorization of funds prior to construction. At present none of the local governments have seen fit to provide the funding that would complete the broader aspects of the plan, and it is probably safe to assume public opinion will bar the complete enactment of the plan in the foreseeable future.
It is obvious that the structures protected by the present groins enjoy a more secure position on the barrier island than homes in unprotected areas. The abundance of shell material in the sediment of the dune ridge at this point is the result of being derived from dredged bay bottom, a practice often abhorrent to local baymen.

STOP 5. is located 13.9 miles west of Shinnecock Inlet on Dune Road immediately west of the last groin in the Westhampton Beach groin field. Here you will see evidence of recent wash-over, damage to local homes, and the absence of any substantial dune ridge. Of course all of this is directly attributable to the position of this beach with respect to the groin field. Starved for sand, it has receded at a very rapid rate.
Currently there is considerable pressure from homeowners and local government for the construction of six additional groins in this area in order to stabilize the beach to Moriches Inlet. The cost of this work will be approximately 10.5 million dollars and would be completed as part of the 1960 plan.
Consideration of how the natural system operates, the interference of man in this system, and interests of local property owners prompts a number of interesting questions.
Can local governmental units with sharp political boundaries deal intelligently with the management of natural systems that do not have the same boundaries?
Should federal projects of the type seen today be allowed to progress without any real assurance that funding will be provided to complete the project?
What will be the likely effect of the construction of six additional groins?
Can the public justify further coastal modifications on the basis of a realistic cost benefit ratio?
If the groin field were to be extended to Fire Island Inlet, would there be enough sand in the system to nourish the westernmost groin?
Does the public owe local homeowners west of the last groin for damages to their property?
To what extent is the damage produced by natural island migration and to what extent produced by the works of man?

A5: ENVIRONMENTAL GEOLOGY OF DEMOCRAT POINT, FIRE ISLAND, N.Y., AND THE JONES BEACH BARRIER ISLAND
ENVIRONMENTAL GEOLOGY OF DEMOCRAT POINT, FIRE ISLAND, N. Y., AND INFLUENCES ON ADJACENT BARRIER ISLANDS
Manfred P. (Fred) Wolff.
ENVIRONMENTAL GEOLOGY OF THE JONES BEACH BARRIER ISLAND
Coordinator:
Peter J. R. Buttner
Lecturers:
Richard A. Brady
Francis A. Hyland
Robert Johnson
Coastal marshes occur as a result of estuarine sedimentation and are now included as a class of distinct landforms. On the south shore of L. I. these marshes, originally well south of this area, are superimposed over the drowned lower coastal plain that extends seaward as the nearshore continental shelf. This region, including past and future sites of salt marsh development, is underlain by a layer of glacial outwash that has been modified into barrier beach-estuarine environments by the rising sea.
The estuary forms a partially enclosed body of water where mainland fresh-water and sea water meet to form a region of shallow brackish water with variable salinity, water temperature. and sediment load. The Great South Bay Estuary System is a 70 mile long "bar-built estuary" extending from Lawrence in Nassau County to Southampton in western Suffolk.

M.P. Wolff, P.J.R. Buttner, R.A.Brady, F.A. Hyland, R. Johnson

STOP 1. -Robert Moses State Park
(Trucks will transport you along the beach for one mile to the jetty at Democrat Point. Walking time is about 35 minutes.)
This area, located at the federal jetty on the western end of Fire Island (and Robert Moses State Park) has been mapped since 1825 when it was located at the tip of the Fire Island Lighthouse - 4.6 miles (7.4 km.) east of its present position. The growth rate now averages 212 feet (71 meters) per year (Figure 1).
The purpose of this stop is to view the effects of the accretionary processes of spit formation from littoral drift and wave refraction associated with a laterally migrating barrier island. A more detailed analysis of the features, processes, and history of this migration is presented in article B-3 of this guidebook.
Because of the necessity for beach nourishment and inlet stabilization, the area is now dredged once every 2-3 years and the accumulated sands transferred to an adjacent feeder beach (Cedar Island and Gilgo beaches) on the west side of Fire Island Inlet. It is unfortunate, that this trip follows shortly after such a period, when only a few features are present. However, participants are invited to return at other intervals during the next few years when all of the characteristic sediment features will again reappear. You are now seeing the initial growth stages of a new intertidal spit platform, but the development of the extensive primary and modified spits and their migration across embayments and lagoons will not reappear until the subtidal spit platform has been built seaward - as was the case once before (Wolff, 1972).
M.P. Wolff, P.J.R. Buttner, R.A.Brady, F.A. Hyland, R. Johnson

STOP 2. Captree Beach State Park
Walk east across dunes to area of highest elevation. From this point one can see the end of the Jones-Captree Beach barrier island, remnants of an earlier extension of Fire Island (Sexton Island and the Fire Islands), and the position of the old and new inlets. All of this area was once exposed to the open ocean. The lighthouse on Fire Island indicates the western edge of that island and the wide inlet that was present over 140 years ago. The barrier beach west of the lighthouse and the now parallel inlet indicate the changes that have occurred since that time. (Wolff, Article A-5-AM.)
Captree Beach and its extensive back-barrier salt marsh (partially dredged for the state boat channel) is toe first area in western Great South Bay with this development, and this initiates the pattern that characterizes the remainder of the barrier island chain to Jamaica Bay. The extension and overlap of Fire Island has curtailed most erosion, though some modification by the ebb and flow of tidal currents continues. Note the bulkheads and the position of the dense scrub vegetation and trees on the dunes near the inlet. Though protected by Fire Island, it also receives no sediment from that source and some erosion continues to persist.
Cap tree is an important bird nesting area and, because of its proximity to the mainland and the inlet, an important area for bathing, boating, fishing and picnicking. Each morning a fleet of fishing vessels leave the boat basin for points within the bay, in the inlet, or in the ocean.
M.P. Wolff, P.J.R. Buttner, R.A.Brady, F.A. Hyland, R. Johnson

STOP 3. Erosion of dunes near West Gilgo Beach.
It is normally dangerous and unlawful to stop here on the road during the summer and parking in the West Gilgo Beach Parking Lot is advisable -but for the sake of completeness there will be a "quick stop" at this point.
This area is characterized by previous beach and dune erosion to the extent that this process has almost reached the position of the Ocean Parkway. Many areas on the adjacent barrier islands - from Fire Island to Rockaway - exhibit similar effects. The sand bypassing from Fire Island Inlet7 coupled with the littoral drift, still assures the preservation of a broad, well-nourished beach at this point and indicates the positive effects of man-made intervention without the necessity of groins. However, the lack of natural sand supply for the more western barrier islands (especially the Rockaways) continues to impose a serious problem. Should attempts at stabilization continue or, considering the long-range effects, should "nature take its course?" These are questions that have important social, economic, and political as well as environmental consequences, and must be handled both on a local and on a regional basis.

STOP 4. Tobay Beach and Bird Sanctuary.
This area will illustrate the creation, development, and maturation of back-barrier tidal salt marshes.

STOP 5. Area for sewage outfall line
Area for sewage outfall line from Cedar Creek Sewage Treatment Plant.
In order to curtail estuarine pollution, a series of sewage outfall lines extending across the bay and beneath the barrier islands into the ocean have been proposed - this is one of the first to be completed (1973). While there is little that can be observed on the surface, the vegetation across the dredged zone (the pipe was 8 feet in diameter) clearly demonstrates the progressive succession of different barrier island species and the return of the native flora.

STOP 6. Parking Field #9 of Jones Beach State Park.
This area is similar to Stop 4. Note the position of the Parking Lot versus the line of the primary dunes and the successive zones of berm accretion. Originally intended to handle the overflow from neighboring Parking Lot 6, after at least two attempts to repair the area, the project has been abandoned. The collapse of the southern edge of the parking lot was due to undermining by lateral erosion. As with Stop 4, each of these areas of extensive erosion are near old inlets. (Wolff Article A5AM.)

STOP 7. Parking Field 5 and Administration Area.
The previous stops have emphasized some of the dynamic natural and man-made changes that are occurring on the barrier islands. Administrative personnel will review some of these processes and explain how the L.I. State Park Commission is trying to achieve a balance between the requirements of the natural environments and the importance of the maintenance and development of public recreational resources (Figure 1). Any man-made structure has a limited life expectancy, usually measured within 1-3 human generations. Coastal zone management with regard to public recreation cannot consider long-range (100-year) changes since the demand for recreational resources varies within 10-20 year intervals. By working within these intervals useful environmental and recreation resource management policies can be established and these can be modified to fit the long-term coastal changes.

STOP 8. West End of Jones Beach, Parking Lot 2.
As with Democrat Point (Stop 1) this area exhibits all the characteristic features of lateral and vertical sand accretion. The construction of the jetty in the 1950's now provides a very wide beach and a wide zone of dune development. Note in particular the type of vegetation associated with these recent dunes.

A6: GEOLOGICAL OCEANOGRAPHY OF A SEGMENT OF LONG ISLAND SOUND AND SEDIMENTARY DYNAMICS OF A COASTAL POND: FLAX POND, OLD FIELD, LONG ISLAND, N.Y.
GEOLOGICAL OCEANOGRAPHY OF A SEGMENT OF LONG ISLAND SOUND
J. R. Schubel
Marine Sciences Research Center
State University of New York at Stony Brook
Stony Brook, New York 11794
The field trip will be conducted aboard the Marine Sciences Research Center's new 55 foot research vessel, R/V ONRUST. The ONRUST, completed in 1974, was designed specifically for work in coastal and continental shelf waters. It is well equipped for work on biological, chemical, geological, and physical oceanographic problems of the coastal environment.
The primary objective of this cruise is to introduce the participants to some of the tools and techniques used by oceanographers in their quest to understand, interpret, and predict the processes that characterize the coastal marine environment. A secondary objective is to use some of these tools and techniques to make a cursory examination of several different sedimentary sub-environments of Long Island Sound. The shortness of the trip precludes a detailed look at any particular area and requires that the cruise be concentrated in the Sound off Port Jefferson Harbor. The actual ship track will be dictated largely by weather and sea state, and therefore no specifics are given in this brief report.
After a variety of methods and instruments have been demonstrated by MSRC staff members, participants will be encouraged to use the devices to collect their own samples, and to make their own measurements. The methods and instruments to be employed; the measurements to be made; and the samples to be collected, fall into several broad categories.
Each participant will be provided with a set of oceanographic data from Long Island Sound and a suggested reading list for possible classroom use in oceanography courses at the undergraduate and beginning graduate levels.
SEDIMENTARY DYNAMICS OF A COASTAL POND: FLAX POND, OLD FIELD, LONG ISLAND, N.Y.
Karl W. Flessa, Glenn A. Richard and Mary K. Cushman
Department of Earth and Space Sciences
Stony Brook, New York, 11794
Flax Pond is a small estuarine marsh located on the north shore of Long Island, New York (Fig. 1). Since 1966 the Flax Pond marsh has been owned by the State of New York and administered by the Department of Environmental Conservation and the Marine Sciences Center of the State University of New York. Under this administration the marsh has been utilized as a research site for studies dealing with salt marsh flora and fauna, estuarine hydrology, nutrient cycling and coastal sedimentation. The protected nature of the Flax Pond marsh and its similarity to other intertidal marshes in the northeast make it a unique scientific resource for the region. In addition to the advantages conferred by state protection, the Flax Pond marsh is situated in an area which was settled early in the history of New York. Historical records which mention Flax Pond date back well into the 18th century, maps showing the pond date from 1797, and accurate coastal charts of the region were first issued in 1852. Thus, the existence of historical records and maps provides an opportunity to study the development of man's interaction with this coastal pond and permits the documentation of the natural and manmade coastal changes of the past 200 years.
The objectives of our research on the sedimentary dynamics of the Flax Pond marsh include the understanding of the processes, rates and environmental controls of sedimentation and marsh growth. We have, to date, utilized information derived from historical records, maps and charts, the stratigraphy of the marsh sediments, and marker bed studies to arrive at estimates of the rates of marsh accretion. A summary of this work is presented in this paper and will be illustrated while in the field. Future projects will utilize radiometric techniques and suspended sediment budgets to arrive at additional estimates of the rates and environmental controls of marsh growth.

A6: GEOLOGICAL OCEANOGRAPHY OF A SEGMENT OF LONG ISLAND SOUND AND SEDIMENTARY DYNAMICS OF A COASTAL POND: FLAX POND, OLD FIELD, LONG ISLAND, N.Y.

The footbridge over the main channel provides an overview of the marsh and its geologic setting. The lighthouse to the ENE is situated atop Old Field Point, a bluff composed of the morainal sediments of the Harbor Hills moraine. The hills to the WNW, terminating in Crane Neck Point, are also composed of this glacial sediment. These bluffs are the source of the sediments on the barrier beach. Topographic, vegetation and surface sediment maps will be displayed on posters at this stop and will provide an opportunity for a description and discussion of the general features of the marsh. See also the section in the paper entitled "The Flax Pond marsh: general features".
Proceed to the northeast through a stand of Iva (the marsh elder) and Juncus (black grass), across a sandy patch which shows how the common marsh grasses spread via rhizomes, and onto a stand of Distichlis spicata and spartina patens. Note how sharply these vegetation zones are bounded. Continue SINGLE FILE (to minimize the damage to the marsh) across the Spartina alterniflora zone to the bank of a small tidal creek. The far bank exposes the stratigraphy of the marsh sediments.

Note the three distinct strata that are exposed here: the Spartina peat at the top, the reddish-brown, finely textured sedge peat, and the underlying coarse sand. Historical records indicate that the transition from sedge peat to Spartina peat took place in 1801. This datable horizon permits the calculation of sedimentation rates for the Spartina peat. Calculated estimates for vertical accretion range from 2.4 to 4.6 mm/yr. Lateral accretion proceeds at the rate of 158 m2/yr. At this site a poster which summarizes the historical information in Table 1 will supplement the discussion of the environmental significance of these strata. Additional background information for this stop is in the article sections entitled "Flax Pond: the historical record" and "Sedimentation rates determined from historical records". Proceed back along the trail toward the footbridge. Instead of crossing the bridge turn to the northwest and walk along the periphery of the wooded upland (probably a submerged kame) to Stop 3.

To the south and west of this stop are bare mudflats, hummocks of spartina alterniflora, mudflats newly colonized by S. alterniflora, and areas with well established stands of the grass. These areas include the sites of our marker bed studies. A poster showing monthly increments of sediment accretion since October, 1974 and cumulative accretion since that time will provide the basis for a discussion of the rates, environmental controls and seasonal patterns of marsh accretion. For additional information regarding this stop see the text section entitled "Sedimentation rates determined from marker bed studies".
Proceed to the east along the margin of the wooded area. We will pass through an extensive stand of Juncus and Iva. On the inner margin of the barrier beach you should note the lobate appearance of the gravel deposits. These lobes appear to be encroaching upon the marsh surface. Their movement is presumably due to extreme storm waves. The area immediately to the west of the inlet was dredged during the 1940's for sand and gravel. Present depths in this area are about 3 meters at low water.

The inlet, stabilized by jetties since 1947, has not been a stable feature of the Flax Pond marsh. Longshore drift and storms have been responsible for changes in the character and position of the inlet. The maps and charts also indicate a change in the dominant direction of longshore drift from westerly prior to 1947 to easterly since that time. A series of maps, charts and photographs dating from 1797 to 1969 will illustrate the major changes in the configuration of the inlet over the past 178 years. For further discussion see the section titled "Maps and charts".

A7: THE LATE QUATERNARY GEOLOGY OF THE MONTAUK PENINSULA: MONTAUK POINT TO SOUTHAMPTON, LONG ISLAND, N.Y.
William Nieter and Walter S. Newman
Department of Earth and Environmental Sciences
Queens College of the City University of New York
Flushing, New York 11367
Bronius Nemickas and Edward J. Koszalka
Hydrologists
U.S, Geological Survey
1505 Kellum Place
Mineola, New York 11501
The Montauk Peninsula is composed of several glacial, periglacial and interglacial units including the Gardiners Clay(?), Montauk Till Member of Manhasset Formation, late Wisconsin drift, and loess. The stratigraphy of these units is complicated by large-scale glacial tectonic structures. The occurrence of two or more drifts in several localities suggests that this area underwent multiple glaciations and that the morainal features may, in part, be diachronous. The surface of much of the late Wisconsin drift is mantled by aeolian sediments that closely resemble loess. Accumulation of the loess is believed to have occurred under true periglacial conditions which created thermokarst features such as the Scuttlehole depression.
Long Island is long and narrow, reaching east-northeastward from New York City to form a fishlike eastward extension of New York State. The island lies south of and is approximately parallel to the Connecticut shore and is separated from it by Long Island Sound. Long Island also forms a north shore of that ocean reentrant known as the "New York Bight".
Although part of the Atlantic Coastal Plain physiographic province, Long Island features a topography almost completely modified by glacial, proglacial, and periglacial processes. Two conspicuous terminal moraines extend almost continuously along the length of the island. The Harbor Hill Drift traverses the northern length of the island. The Ronkonkoma Drift traverses the central length and constitutes a major part of the south fork. The island abounds in other glacial and proglacial features, such as the coalescing outwash fans and aprons that form much of the southern part of the island.

A7: THE LATE QUATERNARY GEOLOGY OF THE MONTAUK PENINSULA: MONTAUK POINT TO SOUTHAMPTON, LONG ISLAND, N.Y.
W. Nieter, W.S. Newman, B. Nemickas, E.J. Koszalka

Enter Montauk Peninsula
Enter Montauk Peninsula and cross Shinnecock Canal connecting Great Peconic Bay (north) to Shinnecock Bay (south).
W. Nieter, W.S. Newman, B. Nemickas, E.J. Koszalka

Southampton College to your immediate right (south)
W. Nieter, W.S. Newman, B. Nemickas, E.J. Koszalka

Morainal knob and kettle topography of the Shinnecock Hills
From Southampton College to this point you are traveling through the rolling morainal knob and kettle topography of the Shinnecock Hills

Moraine bends to NE
Outcrop on north side of road showing head of outwash. The moraine at this point bends sharply to the northeast.

Southampton to south
Village of Southampton approximately 1 mile south
of the road.

Ronkonkoma Terminal Moraine
The trace of the Ronkonkoma Terminal Moraine can be seen to the north with the outwash plain abutting against it. The outwash is covered by thin loess in this area.

Entering head of Mecox Bay, Mill Creek on south.

Duck Farm
One of the numerous Long Island duck farms can be seen on immediate left on north shore of Hayground Cove which enters directly into Mecox Bay. There is considerable controversy concerning periodic eutrophication of the water mass caused by nitrogenous wastes from these farms entering the bay.

Scuttlehole depression
On north and south of road observe the southernmost extension of the Scuttlehole depression. Kellis Pond is to the south and occupies most of the depression. (See text and description of Stop 6 for details of origin.)

Village of Bridgehampton.

Sand and gravel pits
Active sand and gravel operation at north side of road. These pits have been dug deeply enough to intersect the water table, and present operations involve dredging methods.

Site of former wave cut cliff.

Leave glacial deposits
Leave glacial deposits and descend onto the Napeague beach complex. Note steep wave-cut bluff to immediate north. This is the central part of the Napeague tombolo. Napeague Harbor is to the north.

Observe wave-cut bluff in morainal deposits.

Observe dunes from north of the moraine.
Dunes have been blown inland and over the moraine for approximately 1 mile.

Ascend the moraine.
Road divides. Bear left and ascend the moraine. The western boundary of Hither Hills State Park is crossed here.

Rapid descent from moraine, entering Montauk Village.

Traveling on beach deposits
Traveling on beach deposits that have been drifted in by long-shore currents. Fort Pond to north has been isolated from the ocean by a double tombolo.

Reascend moraine.
Several overlooks on the road provide beautiful ocean views on clear days.

Oyster Pond can be seen in the distance to the northeast.

STOP 1. Montauk Air Force Station.
Here along the littoral bluffs on Long Island's southeast coast which includes the type section of the Montauk Till, we have the opportunity to examine the excruciating complexities of the island's Quaternary stratigraphy. The hoodoo topography developed on the Montauk Till provides a conspicuous marker bed which enables us to follow the till where it outcrops along the eroding bluff. However, the complicated glacial tectonics, immediately apparent in these exposures, has detached blocks of Montauk Till, and these blocks have been transported into anomalous stratigraphic positions. To our west, stratified drift beneath the Montauk Till is exposed in a large mile-wide antiform. Stratified drift including laminated silts and clay, frequently folded and in fault contact, also lie above the Montauk Till. The barely finite age obtained from a log in the lower portion of the upper stratified drift, has been previously noted while a second date on disseminated wood from the upper stratified drift dates at 12.170 ±180 years B.P. (QC-122 ). Discontinuous lenses of a younger till cap portions of the bluff. Also found in the upper part of the section are pockets of loess up to ten feet thick.

STOP 2. Ditch Plains.
The Montauk Till forms the base of the section exposed along the coastline. Close inspection of the till reveals pervasive deformation. The western end of our traverse displays well-developed hoodoo topography on the Montauk Till. The western portion of the section shows stratified drift and loess above the till. At the eastern end of the high bluff, thinly bedded fine sand dips towards the east and passes from view beneath the beach. This stratified deposit lies upon a persistent peat zone upon which rooted stumps are occasionally exposed. As noted previously, a radiocarbon date on one of these stumps shows it to be about 5500 years old. Excavation at the east end of our traverse (near where we enter upon the beach) discloses the following section:
Eolian sand
Peat
Laminated silt (lacustrine?)
Montauk Till
Since the peat appears to be mid-Holocene in age, the thinly bedded sand body appears to be the distal portion of a delta that was built into the Ditch Plains basin prior to the Holocene marine transgression of the area. We cannot explain why the late Holocene sand wedge was deposited. We suspect that it might have been deposited because the vegetation cover was temporarily destroyed allowing the mobilization of considerable amount of sand.

STOP 3. Montauk Sanitary landfill.
This section reveals at least 100 feet of stratified sand in the middle of the Ronkonkoma kame-moraine complex. The topographic maps of the area as well as air photos (figure 5) display a series of northeast striding ridges superimposed upon the moraine. These ridges appear to be push moraines. The deposit exhibits both folding and faulting, including several large thrust faults. The section is capped with a bouldery deposit that is probably till. The high percentage of boulders suggests the till has been washed and the boulders at least in part, represent a lag deposit. (Perhaps the term "flowtill" is appropriate here.)

Overlook on right side of road
Overlook on right side of road shows numerous beach and littoral features on north side of Montauk Peninsula. The Atlantic Ocean is to the immediate south.

Lunch Stop and Rest Rooms

A prominent wave cut bluff is directly to the north.

Magnificent dunes
Magnificent dunes can be seen on both sides of the highway. They are presently stabilized by vegetation.

Napeague Harbor can been seen on the right.
Beach ridges, dunes and lagoonal sediments typify this area.

STOP 4. Gravel pit at Amagansett.
Here is the last easternmost exposure of the Late Wisconsin drift to he seen before its termination at Bluff Road sea cliff and its reappearance 4 miles east-northeast at Hither Hills. The till at this stop has a sandier texture, fewer boulders, a lower clay content, and fewer glacial tectonic structures than the Montauk Till. The stratified drift underlying the till is postulated to be either an Early Wisconsin drift that was overridden and deformed by the Late Wisconsin advance or a Late Wisconsin proglacial outwash that was overridden by the advance. The lower stratified drift exhibits many glacial tectonic structures such as thrust faults and folds. This same unit also has preserved depositional structures such as cross bedding and graded bedding. A third unit of wind-blown sediments overlies the till.

STOP 5. Easthampton Bus Company
This stop is included to illustrate the late-glacial loess deposit and the surficial sands that have blown in and partially covered the loess in the Easthampton area. The flat bulldozed surface is near the top of the loess deposit. It is possible to dig down through some 62 inches of wind blown silt and enter coarse stratified sands and gravels below. The contact between the loess and the underlying glaciofluvial deposits is erosional and a lag gravel concentrate has been developed with many wind-abraded clasts and ventifacts which were left behind during a period of aeolian deflation. Frost action (cryoturbation), probably in late glacial times, disturbed much of the section and introduced the erratic pebbles into the loess from below. After deposition of the loess and some soil formation on the loess, dune sand was blown in from the south shore and heaped into 10-foot dunes in this area. The sands are now stabilized by a soil profile and by a mature forest cover. A minor paleosoil can be seen within the dune sands. The dune sands have stripped much of the A soil horizon from the top of the loess but the B horizon is still present here.
The dune sands are traceable on topographic maps and aerial photographs to the south shore and have blown inland at least 2.2 miles (3.5 km). The sequence of events determined from this and other similar outcrops in this area include: 1. deposition of the last glacial outwash sands and gravels 2. widespread aeolian deflation and the formation of lag-gravel concentrate and ventifacts 3. deposition of the loess on a cold barren surface devoid of vegetative cover and intense cryoturbation of the deposits. 4. indeterminate length of time during which a soil formed on top of the loess. 5. deposition of dune sand from the south shore, probably shortly after sea level reached near its present level. 6. stabilization of the dunes by soils and forest.

In this area, the outwash plain is blanketed with loess.
The trace of the Ronkonkoma Terminal Moraine can be seen directly ahead.

STOP 6. The Scuttlehole Depression.
The Scuttlehole depression is a large topographic feature some 2.5 miles (4 kilometers) in length. It is impossible to observe the entire structure from anyone point on the ground. Therefore, reference to a topographic map (Sag Harbor quadrangle) is recommended.
Our bus stop is on Scuttlehole Road just south of Shorts Pd. and just north of Haines Pd. To the north and south you can observe a topography that is strange for Long Island, reminiscent of karst topography. The elevation of the outwash plain (out of view from this point) on both sides of the depression is approximately 70 feet and the plain is amazingly level considering the nearness of the Ronkonkoma Terminal Moraine which is about 1 mile to the northeast. In this area, only glaciofluvial deposits and aeolian loess are known on the outwash plain. No till or ice-contact deposits or erratics are found on the outwash plain so the presence of glacial ice far south of the Ronkonkoma front is doubtful. The Scuttlehole depression heads near the moraine and extends southeast about 2.5 miles (4 kilometers) and consists of more than a dozen semi-isolated basins identical in size and shape with the two that can be observed here. The basins are steep-sided and flat-bottomed and are isolated from one another by shallow divides.
Several characteristics have led us to conclude that this feature is a collapse structure of thermokarst origin:
1. linearity of trend approximately 2.5 miles (4 kilometers) N25W.
2. beaded drainage system, an often observed phenomena in present-day periglacial areas.
3. size and shape of the individual basins are almost identical to present-day regions of active thermokarst.
4. lack of evidence for the existence of glacial ice in the area of the out-wash plain.
5. association with small scale periglacial features such as cryoturbated loess and a single ice wedge cast of the Scuttlehole depression.
Although not conclusive, we feel the evidence merits consideration and any discussion of the interpretation would be welcomed by the authors.

Outwash grades into kame and kettle topography
Note here how outwash abruptly grades into the kame and kettle topography of the moraine.

STOP 7. Southampton Sanitary Landfill Site.
At this stop one sees a contrast in morainal morphology between here and the previous sites. Here kame and kettle topography predominates as compared to the "push" topography seen earlier. At this site one sees mostly primary sedimentary structures, although secondary structures formed by glacial tectonic activity are present. Geophysical investigations have indicated a finer till-like material at a lower level of the pit, possible equivalent to the Late Wisconsin till.

A8: GEOTECHNICAL CONSIDERATIONS AT SHOREHAM NUCLEAR POWER STATION
Douglas S. Pierce and Peter K. Taylor
Stone &. Webster Engineering Corporation
Boston, Massachusetts
Long Island Lighting Company's Shoreham Nuclear Power Station is one of the largest engineering projects ever undertaken in eastern Long Island. It has required geotechnical considerations of a scope unique to nuclear-fueled electric generating facilities, and has been scrutinized closely by the general public and by various governmental regulatory agencies. This field trip will provide an opportunity to discuss the geotechnical investigations and decisions that are a part of nuclear power plant siting, design, licensing, and construction, and will include a tour of the facility itself, which is scheduled for completion in 1977.
GEOLOGIC SETTING
Shoreham Nuclear Power Station is located on the north shore of central Long Island, at the approximate landward edge of the Atlantic Coastal Plain (Figures 1 and 2). The crystalline rocks of the New England Piedmont slope gently seaward an estimated 1100 ft beneath the site. Overlying this deeply weathered remnant of the Fall Zone peneplain (Suter and others, 1949) is a thick sequence of unconsolidated coastal plain sediments of Upper Cretaceous to possibly Tertiary age. Long Island itself owes its existence to a somewhat linear accumulation of glacial debris unconformably overlying the coastal plain deposits. The island is separated from New England by a glacially over-deepened channel.
SITE VISIT
Due to the nature of this particular field excursion, a detailed road log will not be presented here. Instead, a lecture with slides will precede a walking tour of Shoreham Nuclear Power Station.

B1: LOWER PALEOZOIC METAMORPHIC STRATIGRAPHY AND STRUCTURE OF THE MAMARONECK AREA, NEW YORK
Thomas L. Pellegrini
SUNY at Buffalo
The rocks of southwestern Connecticut and southeastern New York can conveniently be divided into two northeast-southwest trending belts. The easterly strike belt is a metamorphosed eugeosynclinal assemblage of mixed clastic and volcanic rock (Hartland Formation and Harrisen Gneiss). The Mamaroneck area is located within this belt on Long Island Sound (figure 1). The strike belt to the west is a Cambrian-Ordovician quartzite-carbonate sequence (predominantly Lowerre Quartzite and Inwood Marble) deposited on a Precambrian basement complex of the Fordham and Yonker's Gneisses. Overlying this miogeosynclinal sequence are the syntectonic and overthrust members of the Manhattan Formation (Hall, 1968a). From the Berkshire Highlands to the Manhattan Prong. these two belts meet along a sharp discontinuity known informally as Cameron's line. Cameron's line is interpreted by many (Clarke, 1958; Gates and Christensen, 1965) as a thrust fault. Locally. in the Manhattan Prong, however. subsequent deformations may have obscured any local discontinuity.

The Granitic Gneiss outcrops on the west side of the road.

Axial region of the later stage fold
After entering the Mamaroneck Quadrangle, continue down Larchmont Avenue through the axial region of the later stage fold.

STOP 1. Larchmont Manor Park.
NO HAMMERING PLEASE! Enter the park along the paved path at the intersection of Prospect and Park Avenues. Proceed southeast (left) towards a small shelter on a promontory on Long Island Sound. The rocks here have been assigned to an amphibolite unit of the Schist and Granulite Member of the Hartland Formation. As the path continues before the clubhouse, it crosses a broad fold in interbedded schists and granulites which formed during the later stage of folding.
Generally, however, the minor folds related to this episode of folding are tight isoclinal folds. The parallel lithologic layering seen throughout this member is believed to be primary in origin. Although metasomatism may have accentuated this layering in the original S0 plane, these gross compositional differences are considered bedding, reflecting a sedimentary or volcanic origin. The early stage of isoclinal folding produced a foliation (S1) generally parallel to the S0. The later stage of folding refolded this early foliation. The S2 foliation produced clearly cross-cuts the S1 here.
Continue down the path towards the shelter past a glacially grooved and striated amphibolite. The numerous interbedded amphibolites to the east of the shelter occupy a persistent stratigraphic position and are believed to be of volcanic origin. Similar rocks have been described at Pelham Bay to the south (Seyfert and Leveson, 1968). Greenish calc-silicate lenses composed primarily of epidote and diopside with calcite are common here and often prominent in the crestal regions of folds. The numerous northerly plunging folds are related to the later stage of deformation. The variation in the angle and direction of plunge of the L2 axes may be due to an additional deformation, or it may be the reflection of the development of L2 on a curvilinear surface. Crosscutting, undeformed pegmatites can be seen throughout the park. These pegmatites probably correspond to the Acadian thermal event.
Across the inlet northeast of the shelter, the interbedded schists and granulites are typical of the rocks of the Schist and Granulite Member although to the north schist may be more abundant. The rhythmic interlayering of these rocks may represent graded bedding.

Outcrops on the west side of the road
The outcrops on the west side of the road near the playing fields behind the Administrative Offices of the Mamaroneck School District contain amphibolites very similar to those seen at STOP 1. Here, however, they are apparently a small isolated lens.

Contact of the Granitic Gneiss and the Schist and Granulite Member.
After crossing the bridge over the railroad tracks, turn left (west) onto Calvert Street across the contact of the Granitic Gneiss and the Schist and Granulite Member.

STOP 2. Pettijohn Park.
These outcrops of Granitic Gneiss lie near the center of this sill-like pluton. Typically this rock is a brown or brownish tan weathering, light bluish gray, fine to medium-grained, biotite-muscovite-quartz-feldspar gneiss. Microcline is the dominant feldspar; garnet is rare and occurs as small scattered grains. Biotite, although relatively sparse, gives the rock a distinct foliation which here trends northeast in accord with the major structures. The more typical fine-to-medium-grained gneiss at this exposure is commonly associated elsewhere with a white, foliated and lineated pegmatite. Although the contacts between the two types of rock tend to be sharp, the lineations and foliations pass without interruption into the more typical granitic gneiss. The pegmatites are therefore mapped as part of this unit.
Smaller bodies of this rock have been mapped throughout this area and the larger ones have been indicated on figure 1. Some crosscutting dikes have been observed within the Harrison Gneiss, however, the other bodies are all concordant. Although the smaller bodies tend to have sharp contacts, a zone of migmatite occurs along the contacts of this large body.

Contact of the Granitic Gneiss with the Schist and Granulite Member
Proceed down Crystal Street across the west contact of the Granitic Gneiss with the Schist and Granulite Member.

STOP 3. Veteran's Memorial Park.
Scattered throughout the park are excellent exposures of the Garnet Gneiss Member of the Harrison Gneiss. These exposures are on the west limb of the later-stage antiform. This member apparently pinches out further north and is not present on the east limb of the same fold (figure 1). The flat glaciated outcrops within and around the parking area expose a distinctly porphyroblastic zone within this member. The rock is more granitic than most of this member and the porphyroblasts are microcline commonly exhibiting Carlsbad twinning. This zone parallels the contact of this member with the Schist and Granulite Member of the Hartland Formation for at least two miles and appears as a distinct unit or units within the Garnet Gneiss Member. Intensely deformed metasedimentary layers are also present in these outcrops.
From the restrooms at the southern end of the parking area, proceed southwest (bearing 250°) across the recently filled valley to a dirt road and then up the east valley wall. PROCEED WITH CAUTION OVER THE CONSTRUCTION DEBRIS FILL! Total distance to the top of the ridge from the restrooms is about one thousand feet. These exposures contain some of the evidence for the volcanic origin of the Harrison Gneiss. The contact of both members of the Harrison Gneiss with the Schist and Granulite Member is always conformably interlayered with that member. As shown here, thin distinct metasedimentary layers, often only an inch or two thick, can be traced for tens of feet without interruption through the Harrison Gneiss. This interbedded contact can be up to 150 feet thick. The interlayering is suggestive of alternating sedimentary and possibly pyroclastic deposition rather than an intrusive or tectonic mechanism. The Prospect Gneiss, a possible western Connecticut correlative, has a similar contact. Crowley (1968, p. 39) believes that the Prospect Gneiss is a metamorphosed volcanic sequence. The Ravenswood Gneiss to the south also has an interbedded contact although Blank (1973, p. 656) considers it to be sedimentary.
Additional exposures of the contact, although quite deformed, can be seen west of the playing fields adjacent to the entrance to the park. The Schist and Granulite Member is exposed in the stream flowing by the nearby Louis M. Klein Middle School. As can be easily seen at this stop, topographic differences usually facilitate the location of the contact.

Recross contact
Recross the contact of the Schist and Granulite Member with the Garnet Gneiss Member.

Axial plane and contact
Cross the axial plane of the early stage fold and the contact of the Garnet Gneiss Member of the Harrison Gneiss with the Quartz Feldspar Gneiss Member. Here the two members of the Harrison Gneiss have been folded against each other (figures 1 and 2).

Quartz Feldspar Gneiss Member
The outcrops in front of the Harrison High School are of the Quartz Feldspar Gneiss Member.

Contact of the Harrison Gneiss with the Schist and Granulite Member
After crossing the west contact of the Harrison Gneiss with the Schist and Granulite Member, turn left (south) onto Mamaroneck Avenue.

STOP 4. Parking lot cuts off Mamaroneck Avenue.
NO CLIMBING ON THE ROCKS PLEASE! These extensive cuts are in the Quartz Feldspar Gneiss Member of the Harrison Gneiss. Large irregularly shaped segregations of quartz and feldspar and the lack of megascopic garnet easily distinguish this member from the Garnet Gneiss Member. Although biotite commonly exceeds hornblende in both members, the great abundance of biotite here accounts for their somewhat slabby appearance. Present throughout both members and evident in these outcrops are small lenses or streaks of fine-grained hornblende, biotite and feldspar usually measuring a few inches by a foot or more. Similar lenses have been interpreted as relict volcanic bombs in the Prospect Gneiss (Crowley, 1968, p. 39) and in the high grade metavolcanics of the Southern Appalachians (Tobisch and Glover, 1971, p. 2212). At the north end of these cuts and along Union Avenue, the contact with the Schist and Granulite Member is exposed. Here the Hartland Formation, on the limb of a small fold (figure 1), contains rusty weathering, sulphidic looking schists. The contact of this member of the Harrison Gneiss with the continuous but folded contact of the Schist and Granulite Member is also interbedded.
Most of the exposures across the Mamaroneck River in the northern part of Saxon Woods Park are of the Quartz Feldspar Gneiss Member. To the southwest, near the Hutchinson River Parkway, the Garnet Gneiss Member is exposed. There it apparently wraps around the nose of the refolded early stage fold (figures 1 and 2) but pinches out before reaching this location.

Recross the folded contact
Recross the folded contact of the Quartz Feldspar Gneiss and Garnet Gneiss Members.

Garnet Gneiss Member
Enter the southbound entrance ramp of the New England Thruway (I-95) passing exposures of the Garnet Gneiss Member and return to the Throgs Neck Bridge.

B2: GEOLOGICAL ASPECTS OF STATEN ISLAND, N.Y
A. Ohan, A. Kureshy and E. Kaarsberg
Staten Island Community College of the City University of New York
The purpose of this Staten Island field trip is to illustrate some of the major aspects of the island's geology. As shown in Figure 1, the geology of this area can be subdivided into four main units as follows :
1. A lower Paleozoic serpentine body that is exposed in the north central part of the island and which displays a northeast-southwest trend.
2. The late Triassic aged Stockton Formation of the Newark Group which overlays the serpentinite unconformably on the northwest. Its beds dip to the northwest and are generally arkosic in character. The southern extension of the Palisades diabasic sill is intrusive into the Stockton Formation.
3. The late Cretaceous aged Raritan Formation. which overlays the Triassic aged unit unconformably, is part of the Coastal Plain sedimentary deposits that outcrop on the southern and eastern part of Staten Island. It dips gently to the southeast and lithologically is composed of sand and clay interbeds.
4. Pleistocene deposits unconformably overlaying the older units almost everywhere on the island.

STOP 1. Serpentinite Outcrop
This outcrop represents the largest continuous exposure of the Central Zone Serpentinite on Staten Island. The rock is a foliated serpentinized peridotite. The dominant mineral is antigorite which has replaced in varying degrees the original olivine and enstatite. The minor constituents are magnetite, brucite, picotite (chrome spinel), picrolite (sheared antigorite) and graphite. Numerous veins are filled with talc, chrysotile or carbonates. Note:
1. The foliation has been deformed into small folds displaying axial planes which are almost vertical and trending in a general northeast-southwest direction.
2. A number of folds are cut by an axial plane oriented slip cleavage.
3. Several small, high angle, northeast-southwest trending faults and associated fault zones.

STOP 2. Serpentinite Outcrop
(This outcrop is in the locality for a housing development and may be eliminated in the near future. If this occurs an alternative exposure will be visited.)
This exposure is located within the Border Zone of the Serpentinite body and is in close proximity to the near vertical Spring Street Fault. The rock is essentially fine grained, foliated and extensively sheared. The principal mineral is antigorite with small amounts of magnetite and brucite. Some porphyritic serpentinite is present with phenocrysts of olivine and magnetite in a matrix of antigorite. Talc, hydromagnesite, aragonite and artinite exist in veins or along shear planes. Note:
1. Topographic expression of the northeast-southwest trending Spring Street Fault Zone.
2. Small folds with axial planes oriented in a northeast-southwest direction.
3. Fault breccia with fragments of serpentinite and Triassic sedimentary rocks.
4. Near-source glacial erratics with fragments of serpentinite, Triassic sedimentary rocks and gneisses (possibly fanglomerates?).
2013: No outcrops appear to be present

Road follows contact of Serpentinite body
This road follows the almost vertical contact of the Serpentinite body and outcrops of this rock can be seen on the right in many places.

Hummocky terrain with poorly developed drainage
Open areas here begin to show hummocky terrain with poorly developed drainage so typical of glaciated areas to the north.

STOP 3. Terminal Moraine Glacial Deposit
Along the beach at the south end of Hylan Boulevard a Wisconsin aged terminal moraine has been clearly exposed by beach erosion. It shows the typical unsorted nature of this kind of glacial deposit with large boulders intermingled with finer rock debris. On the beach itself these boulders are left stranded after wave action and near-shore currents have removed the finer material. The great variety of composition that these boulders show bespeaks the great variety and far flung distribution of their source areas. For example the dark diabase boulders probably came from the Palisades Sill structure only a few miles to the north whereas many sedimentary boulders found on Staten Island often contain marine fossils which indicate that they probably came from rock exposures in east-central New York or northwest New Jersey.
In places further along the beach remnants of stratified glacial outwash deposits may be found.

STOP 4. Raritan Formation Outcrop
The outcrops in the quarries in this area represent largest continuous exposures of Cretaceous sedimentary deposits found on Staten Island. Two members of the Raritan Formation belonging to the Gray consolidated clays and the Red consolidated clays are represented at these exposures. The Gray colored clay deposits are characterized by the presence of lignite fragments and pyrite. The Red colored clays apparently do not contain any of these materials. These deposits are also characterized by various sedimentary structures of which cross stratification in the sands is one.
Samples of these deposits were processed for the study of any microfossil fauna, but none were recorded. Neither were any plant fossil remains found.

B3: NATURAL AND MAN-MADE EROSIONAL AND DEPOSITIONAL FEATURES ASSOCIATED WITH THE STABILIZATION OF MIGRATING BARRIER ISLANDS, FIRE ISLAND INLET, N.Y. AND A MAJOR BEACH EROSIONAL CYCLE AT ROBERT MOSES STATE PARK, FIRE ISLAND
NATURAL AND MAN-MADE EROSIONAL AND DEPOSITIONAL FEATURES ASSOCIATED WITH THE STABILIZATION OF MIGRATING BARRIER ISLANDS, FIRE ISLAND INLET, NY
Manfred P. (Fred) Wolff
A MAJOR BEACH EROSIONAL CYCLE AT ROBERT MOSES STATE PARK, FIRE ISLAND, NY
Imre v.Baumgaertner
Columbia University, Department of Geology, N.Y.
Fairleigh Dickinson University, Rutherford, N.J.
A major beach erosional cycle at Robert Moses state park, Fire Island, NY, during the storm of 1-2 December 1974: The confirmation of "Grazing-Swash Undercutting" as a major beach erosional mechanism.
At the present time the beaches around the world's coastlines, in general, are undergoing erosion (Tanner and Stapor, 1972). This applies not only to beaches "stabilized" by man, but also to areas where man's influence has not as yet disturbed the natural dynamic balance of the coastal zone. Where man has interfered directly with the natural movement of littoral drift by "improving" the shoreline or where large areas of the coastal plain have been altered for the sake of human progress, beach erosion has been more pronounced.
The quasi-universal problem of beach erosion may result from or is complicated by the many parameters that determine beach and shore dynamics, but the basic cause is the shortage of sand on and around the beaches.
Our problem at the present is further burdened by the fact that the "state of the art" in beach-erosion research has not as yet progressed to such perfection. We are unable to predict the kind of processes and the magnitude of transport on or off the beach for a set of approximate energy-input parameters, and we are far from describing the expected short- or long-term geomorphic changes.
Progress has been slow mainly, because hydraulic engineers (who alone possess the large and expensive apparatus needed for controlled experiments) are less interested in discovering the underlying principles of nature than finding an approximate empirical formula of limited scope. "None of the many empirical theories have either been confirmed or rejected by critical experiments designed to test the various arbitrary assumptions made" (Bagnold, 1968, p. 45).
In this report an explanation is offered for one of the hitherto-unexplained problems in beach-erosion studies - namely the origin of berm scarps, vertical scarps up to 2 m or more in height encountered in the berm and sometimes in the primary dunes. Scarps of various magnitude have often been described in passing (Thompson, 1937, Rosalsky, 1944. Ruzyla. 1972 among others). They have often been encountered by the author along the southern shore of Long Island - but no satisfactory explanation for their origin has ever been postulated.
The clue to the origin of these scarps was documented about 4 years ago when a scarp formation was observed and first recorded in detail by the author while in this area. Additional data resulted from the clear definition of events and the identification of the causes associated with the formation of these berm scarps. Finally, the storm of 1-2 December 1974 demonstrated the close-to-maximum erosional capability of this process in detail.
The following section describes the general wave and wind regime for the Fire Island area. Details of the weather pattern before and during the storm are also documented. A description of the subsequent loss of sand from the beach during the storm is followed by a brief explanation as to the nature of the erosional mechanism. The process of erosion, initially called "swash undercutting" (Baumgaertner, 1973) has been changed to "grazing swash undercutting" (Sanders and Baumgaertner, 1975) because of its sporadic nature on the beach foreshore.

STOP 1. Gilgo Beach
This area has been designated as one of the western feeder beaches used to disperse sands dredged and pumped from Democrat Point and Fire Island Inlet by the Army Corps of Engineers. Located on a barrier island between Jones Beach and Fire Island Inlet (Figure 1) it has undergone numerous natural and man-made changes during the past 150 years principally related to sand migration by longshore drift and a rising sea. Numerous inlets were present some years ago, but all of them have since been closed by the construction of the Ocean Parkway and the littoral drift.
The purpose of this stop is to view the erosional and depositional features of a feeder beach. With a horizontal shoreward rate of erosion of 3 feet (1 meter)/year during the past 15 years (Everets, 1973), nearly 10 million cubic yards of sand have been artificially added to the beaches between here and Fire Island Inlet since 1959. The beach now has its nearly maximum seaward and vertical extent because of recently completed sand bypassing operations terminated in April. 1975. The oceanographic information for this area is in article A-5 of this guidebook. Additional data and reference sources for this area are in the study by Everets.

STOP 2. Democrat Point
This area, known locally as Democrat Point, has been mapped by the U.S. Coast and Geodetic Survey since 1834, and has been recognized as a classic area of rapid, complex spit growth adjacent to a man-modified parallel inlet (Shepard and Wanless, 1971). During the period of 1834-1940 it has grown westward 4.6 miles (7.4 km.) from the Fire Island Lighthouse to the federal jetty at an average rate of 229 feet (76 m.)/year (see Figure 9).
The purpose of this stop is to view the complex spits and other sediment features, to explain their origin and migration patterns, provide some data on flow conditions and grain size parameters, and to examine the surface and subsurface sediment features.
Because of the present necessity for sediment bypassing across Fire Island Inlet to the western feeder beaches at Cedar Island and Gilgo (as noted at Stop 1) the area is dredged periodically. It is unfortunate that this trip follows after such a period -the last dredging operation ceased in April, 1975 and only remnants of the intertidal spit platform are currently preserved. However, participants are invited to return at other intervals during the next few years when some of the features described for this stop will again be more evident. A single trip to Democrat Point and Robert Moses State Park has always been more meaningful if it is followed by another excursion within a few months to note the rapid changes.

STOP 3. Beach foreshore and berm
Beach foreshore and berm at Robert Moses State Park (Figure 1). Since the trip to Democrat Point is timed to coincide with low-tide, grazing swash undercutting, even if operating, cannot be observed. A trench across the berm will be examined to reveal details of the very recent history of the beach.

B4: JAMAICA BAY: A CASE STUDY OF GEO-ENVIRONMENTAL STRESS
Steven Englebright
Department of Earth and Space Sciences
State University of New York at Stony Brook
Stony Brook, New York, 11794
Jamaica Bay is the westernmost of the estuarine marshes which lie behind a system of barrier beaches along the south shore of Long Island (Figure 1). Horseshoe shaped, the bay is encircled by a gently sloping glacial outwash plain along its northern perimeter and by the elongate Rockaway barrier beach to the south. Human activities have fundamentally changed the surface character of the region and disrupted the natural geologic processes. The purpose of this paper is to examine the historic relationship between the natural geological environment and human activities.

STOP 1. Early boundary of the Bay
This street corner is approximately on the boundary of what was, at the turn of the century, the shore of Jamaica Bay. Stretching out before you to the south was one of the great salt marshes of the northeast. Its 16,000 acres were penetrated by shallow meandering channels bordered by smooth chord grass, Spartina alterniflora. A broad belt of high marsh, the outer edge of which was approximately where we stand, was covered by Spartina patens. Notice that today you cannot even see the bay from here. The urban development that is apparent everywhere in this vicinity is typical of almost all of the former upland margins of Jamaica Bay.

STOP 2. The building on your left is the South Shore Incinerator.
In 1960 there were 2.5 million people living in New York within 5 miles of Jamaica Bay. The solid waste this large population produces is a serious disposal problem. By burning solid refuse, its volume can be reduced by as much as 90% and make its ultimate disposal considerably more efficient. As urban growth took place around the bay, solid refuse was used as landfill. This plant is built on filled marshland.
The South Shore Incinerator receives solid wastes from western Queens and most of Brooklyn. Collection trucks dump material into a waiting bin until it can be placed directly into one of four furnaces. The refuse is its own fuel unless it has rained, in which case oil is sometimes added to keep the furnace hot. The standard temperature is 1500-1600°F and the plant is kept operative 24 hours per day, Monday through Saturday. (On Sunday the furnaces are cleaned which explains the quiet, inactive atmosphere here today.) After incineration the residue is carted to a landfill. Before boarding the bus again, examine some of the ash (refuse) where it is piled outside the south end of the plant. After burial in a sanitary landfill these ashes will cause groundwater percolating through the fill to become highly acidic. Because of leaching, sanitary landfill sites, especially those immediately adjacent to the bay, can be expected to be a continuous pollution source.

STOP 3. Fountain Ave Landfill
As New York City grew around Jamaica Bay, it used the bay waters for disposal of liquid waste and the fringing marshlands for the disposal of solid waste. We are at the Fountain Avenue landfill. Some six thousand tons of solid refuse are brought here each day. There are two kinds of solid waste disposal sites: 1) a sanitary landfill consists of refuse which is sprayed with a germicide and periodically covered with a sand or earth cover; and 2) a garbage dump, which is simply an open disposal site. Before 1933 the City dumped most of its solid waste into the ocean, but it was forced to stop this practice after a Supreme Court ruling specifically prohibited it. Partly as a result of this, the deposit of solid wastes around the periphery of the bay increased in the 1930's just as sewage treatment programs were getting under way. Between 1938 and 1971, 10 million cubic yards of sand was dredged from the bay for sanitary landfills along the north shore of Jamaica Bay. In 1965, Brooklyn and Queens each produced 1.7 million tons of solid waste of which 947,000 tons were deposited in Queens, much of it on the Jamaica Bay marshes. This 300 acre landfill was begun in November of 1961. It is scheduled to operate until 1985 at which time it will become a park.

STOP 4. Beach Restoration
Walk up the stairs and go to the ocean side of the boardwalk. Sand trapped in artificially maintained inlets further west has been denied to the Rockaway barrier beach and portions of it have become so severely sand starved as to require artificial beach nourishment. By 1974 the berm in this area was completely gone, erosion of the boardwalk was occurring, and in places the shore parkway was threatened. The wide beach we see today is the result of a current ten million dollar beach restoration project begun in April and administered by the Army Corps of Engineers. By the time this project, the first of three between Jones and Rockaway inlets, is completed in November, 4,950,000 cubic yards of sand will have been placed along the shore between 110th and 45th Streets. The sand is obtained by dredging from a huge accumulation known as the "East Bank" some two miles off of Breezy Point. There it is loaded onto barges which transport it to a "booster" dredge-pump on the bay side of Rockaway Beach. Mixed with water it is then pumped under pressure through steel pipes across the barrier to the ocean side. Sand placement is progressing, steplike fashion in an updrift, i.e., easterly direction. By early September, under the influence of the prevailing westerly drift the area was acting as a feeder for the beaches further west.

STOP 5. Jamaica Bay Wildlife Preserve
We are in a National Park. Please read and obey the posted rules and regulations. Despite its natural look, this too is a man-made environment. Dikes around the two fresh ponds have been landscaped with abundant varied vegetation to attract wildfowl. Besides being a major nesting area, the Jamaica Bay Wildlife Preserve lies on the Atlantic Flyway. Over 300 species of birds have been seen here.
However, our main purpose in stopping here is to collect, not objects, but rather ideas, concepts, and impressions. This is a place of contrasts. Evidences of both positive and negative human interactions with nature are apparent everywhere; on the horizon and under your feet.
The guide for this part of the trip is yourself. Be sure to "synchronize watches" with everyone else before leaving the bus. Your challenge is to discover, observe, and reflect upon what you have seen today, as well as what you are about to explore. Stay on the trails and be sure to return by the appointed time.

B5: WISCONSINAN GLACIAL STRATIGRAPHY AND STRUCTURE OF NORTHWESTERN LONG ISLAND
Les Sirkin
Adelphi University
Herb Mills
Museum Supervisor
Nassau County Department of Parks
The most detailed report on the geology of Long Island is that of Fuller (1914). In this work, Fuller developed a detailed stratigraphy which incorporated the Pleistocene sediments of Long Island into the classical stratigraphy of 4 glacials and interglacials recognized in the midwest. Fuller's work, built on such preceding studies as Woodworth (1901) and others, contains many excellent stratigraphic sections, but it is restricted to the "state of the art" for that time. More recent contributions such as Fleming (1935), MacClintock and Richards (1936), deLaguna and Perlmutter (1949), Swarzinski (1963), Donner (1964), and Sirkin (1967, 1968, 1971, 1972, and 1975, and Sirkin and Stuckenrath, 1975) began to revise the stratigraphic interpretations, mainly in limiting the number of glaciations to mappable drift sheets. With the aid of palynology and radiometric dating, recent authors have been able to place the rock units into a more refined time scale.
Pollen analysis has shown that at least two cold episodes, corresponding to glacials, and possibly three warm intervals, an interglacial (?), and interstadial, and the postglacial, have taken place here (Sirkin, 1967, 1971, 1968, 1972, and 1975, and Sirkin and Stuckenrath, 1975). Additional information about glacial deformation has provided a better understanding of the complications observed in the stratigraphy (Mills and Wells, 1974). The recent discovery of interstadial deposits has also brought about a change in the interpretation of the stratigraphy of only a few years ago in which the trend seemed to be toward monoglaciation (Sirkin, 1968, and Connally and Sirkin, 1973). Prior to this discovery much of the confusion was centered around the incorporation of morainal terminology with stratigraphic units. This fostered a sort of morphostratigraphy in which drifts were named and associated with moraines. The observation that the moraines were constructed of superposed drifts (Sirkin, 1968) and the introduction of the new data (Sirkin, 1975, and Sirkin and Stuckenrath, 1975) has made it possible to distinguish between geomorphology and stratigraphy.

STOP 1A. Remanent area, known as Billy Goat Hill (Fig.3A).
2013: Google Earth imagery from 1994 shows some active mining, but much of the area was already being reclaimed. All locations of the stops are guesses.
This location has an apparently undisturbed 2 till - 2 outwash sequence (outwash-till-outwash-till). There is a 5-6 m layer of tan gravelly sand at the base of the cliff, which rests on clayey Cretaceous sands not far below the surface. A compact gray-brown till of fairly uniform thickness (about 2m) overlies the outwash. Abundant cobble and small boulder sized erratics can be seen in this till, and at one point a prominent boulder lag occurs at the top of the till. If this lower outwash and till are attributed to the early Wisconsinan glaciation, the till would be the Montauk Till equivalent on western Long Island. Above this till is another thick (8-10 m) outwash similar to the lower outwash, except with more prominent oxidization zones due probably to groundwater movement. A second till, well cemented and of variable thickness (2-4 m) overlies the upper outwash. The upper outwash and till represent late-Wisconsinan drift commonly observed in western Long Island.
In both cycles outwash and lodgement till were deposited. The lag boulder zone on the Montauk (?) Till may represent a mid-Wisconsinan erosion interval. Large boulders resting on the Roslyn Till (Sirkin, 1971) and numerous kames and minor kame-like moraines on the Necks north of the Harbor Hill terminal moraine are products of late Wisconsinan deglaciation.
It might be noted that Fuller (1914) placed the top of his Manhasset Formation (of Illinoian age in his time scale) above the upper outwash (his Hempstead Gravel). As will be seen at later stops, an angular unconformity often occurs at this horizon due to late-Wisconsinan deformation. No significant depositional hiatus can be justified between the upper till and outwash.
Proceeding to Stop 1B notice the persistent thickness and elevation of Montauk (?) Till. The late-Wisconsinan drift has been largely removed at several points by the sand mining. Other features of note are the well formed and sorted talus cones, mud cracks, and quicksand (BEWARE) if conditions are right.

STOP 1B. 1/4 mile west of Stop 1A (Fig. 3B).
The Montauk(?) Till is dramatically thicker at this location due to ice-shove deformation associated with the late Wisconsinan advance. A light reddish iron stain marks a folded thrust plane indicating that the relatively thin, undisturbed lower till of Stop 1A has been increased in thickness due to folding, faulting and probable flow. Dramatic changes in the thickness and position of the Montauk(?) Till have been described by Mills and Wells (1974) and can be seen at Stop 2 of this trip.
The thick till at Stop 1B is well cemented, contains many cobble and boulder-sized erratics, and exhibits the sharp ridge and pinnacle "hoodoos" also seen in the Montauk Till at Montauk Point. A till fabric in this till revealed a northeasterly source direction. When traced along the outcrop to the west, this till again thins and assumes an apparently undisturbed horizontal altitude. Above the disturbed section of Montauk (?) Till, there is an unusually thin deposit of late-Wisconsinan drift capped by about 2 meters of loess. A gravelly zone in the Roslyn Till may indicate a local flow till or outwash. To the west, the upper outwash thickens and the section looks much as it does at Stop 1A. Across the landfill site, a lighter area in the cliffs marks the site of an ice transported clay lens of probably mid-Wisconsinan age. This localized deformation is typical of the glacial stratigraphy north of the terminal moraine.

STOP 2A. North end of sand pits (Fig. 3C).
This section described by Sirkin (1968) and redefined by Mills and Wells (1974) exhibits several meters of gravelly outwash at the base, a large thrust block of ice-shoved Cretaceous sands, clays and gravels, and unusually thick, bouldery layer of Roslyn till. The Cretaceous thrust block, one of several (Fig. 4), is about 15 meters thick with a gravelly zone of rotted quartz pebbles near the top. The basal thrust plane is marked by a thin purplish clay and occasional small folds. There is also a less obvious thrust plane within the Cretaceous which is noticed by an offset in the gravel zone. The brown silt that covers the cliffs just south of Stop 2-A is sediment from an old settling pond that was placed on the cliff to slow the erosion.

STOP 2B. about 500 meters south of 2-A (Fig. 30).
A prominent erosion pinnacle of thick Montauk (?) Till with ice-shoved Cretaceous draped over the top is the highlight of this stop. The till dips steeply and pinches out less than 100 m to the north. To the south, it dips below thick talus and reappears at a lower elevation in the bluffs. The till then enters a large, almost 50 m high fold, swelling in thickness in the synclines and pinching out over the crest of the anticline (Fig. 4). Rising at a steep angle on the south limb of the fold, the till is truncated by the flat lying Roslyn Till at the surface.
The Cretaceous thrust block draped over the till pinnacle thickens rapidly just to the south and then tapers to a long wedge and pinches out above the large fold. The northerly, butt end of another Cretaceous thrust block is in contact with the steeply rising Montauk (?) till on the south limb of the fold. Thick, deformed outwash units (early-Wisconsinan below and late-Wisconsinan above theMontauk (?) Till) complete the deposits seen in this section, except that presumably in place Cretaceous beds are exposed in the lower elevations of the mining pits.
Other features of note in this vicinity include: a spectacular boulder field with erratics collected from source areas as far away as the southern Adirondacks, numerous Cretaceous iron-oxide and pyrite concretions, a deformed Cretaceous clay and lignite, containing pollen of Raritan age (Sirkin, 1974a); many crystalline quartz ventifact cobbles located on the Cretaceous surface suggesting strong periglacial winds (Mills and Wells, 1974); and a cobble filled stream channel cut into the Cretaceous thrust block beneath the Roslyn Till, just to the left of the Montauk (?) Till pinnacle.

STOP 3. Mid point on west wall
Approximate mid-point of the sand pits, along the west wall, northwest of STOP 1.
The section of peat, clay and oyster reef stacked in the late Wisconsinan drift has provided important new information on the late Pleistocene stratigraphy of Long Island. The dark layers in the cliff (Fig. 3E) are peat and clay layers. The structure of the section is similar to those already observed to the north. The beds have been recumbently folded and somewhat thrusted. The axes of the folds are nearly horizontal, and the peat and clay beds are often over thickened (doubled) or telescoped into greater thicknesses. The two main shell bearing horizons on the north side of the section represent the same unit with the underlying sequence overturned. Both have been folded into small synclines and are over thickened along the axes of the fold. They consist mainly of peat, marine clay, oyster reef, and thin interbedded till and outwash. A series of over 20 radiocarbon ages have been determined by Bob Stuckenrath of the Smithsonian Radiation Biology Laboratory. The dates represent a sampling of all of the units and of different materials from each layer including peat,shell and wood. The ages range from > 43,800 to 23,000 years B.P. and with the pollen data have made it possible to reconstruct the sequence of environments and vegetation during the mid-Wisconsinan interstadial and high stand of the sea. The brown peats lower in the section represent fresh and salt marsh deposits formed over 35,000 years ago in the western end of what is now Long Island Sound. These peats contain pollen of pine, spruce, birch, alder and non-arboreal pollen (NAP). These pollen spectra suggest boreal vegetation, like the northern needle leaf forest or taiga in northern Canada, and cold climatic conditions at the end of the early Wisconsinan glaciation. The shell beds, dated around 31,000 years B.P., contain pollen of pine, hickory, black gum, oak, birch, and minor hemlock and NAP. This assemblage indicates a much warmer climatic regime and a regional forest composed of pine, oak, and hickory. The black gum suggests a coastal setting. These sediments also contain foraminifera similar to those of the Sound today. Overall, the climate and vegetation are similar to the modern climate and vegetation in this area. Evidence of cooling is seen in the pollen from the peats and clays dated at 28,150 years B.P., found above the shell zones. These sediments contain pine, alder, birch, hemlock, oak, and NAP; the indicators of warm temperate conditions have dropped out of the record or are only minor elements. Within the next few hundred years rather cold climate developed in this region as seen in the pollen record. Pollen of pine, birch, spruce, and alder suggest a return to boreal forests and cold, moist conditions by 27,900 years B.P. This evidence heralds the onset of the late Wisconsinan glaciation. The last radiocarbon date in this sequence, an age of about 23,000 on spruce wood may be the maximum age for the arrival of the late Wisconsinan glacier on Long Island, and for the deformation of the interstadial and subsequent deposits.

STOP 4. Northerly facing bluffs at south end of pits (Fig. 3F).
Although only 1 mile south of Stop 1, the section here appears markedly different. Instead of the two distinct tills of Billy Goat Hill, the Montauk (?) Till is represented by a series of thin tills interbedded with thin layers of orange , oxidized outwash. The Roslyn Till at the surface is much less pronounced here and in places may be absent completely. Fuller (1914) noted lateral changes in the Montauk (?) Till, and Mills and Wells (1974) found an orange outwash phase of this till at the north end of the sand pits. Facing the main section of slopes and looking eastward, the Montauk (?) shows a facies change from the thin interbedded till and outwash to a single thicker till with outwash above and below. Since this outcrop is located at the foot of the proximal slope of the Harbor Hill terminal moraine, we may be observing lateral facies changes associated with glacial deposition.
At the low outcrop near West Shore Road, a thin bedded deposit probably of lacustrine origin covers the Montauk (?) Till. The late-Wisconsinan drift is very thin with no till, and the section is capped with loess.

STOP 5. About 100 m northwest of the stairway.
STOP 1. About 100 m northwest of the stairway.
The cliff section reveals a sequence of outwash, till, outwash, and loess. At the base, from the level of the beach upward are approximately 5 m of glacial outwash composed of stratified sand and gravel. A compact, brown till (a sandy loam with abundant cobbles and boulders) about 1 m thick overlies the outwash. Above the till another unit of stratified sand and gravel (outwash?) forms a lens pinching out to the southeast and thickening to about 2 m to the northwest. The height of the cliff diminishes southward as this unit pinches out. The section is capped by about 1 m of loess. On the beach there is an abundance of cobbles and boulders. Diabase and purple-red puddingstone conglomerate erratics, along with till fabrics and other rock compositions suggest a northwesterly source area for the till. The diabase may be derived from the Palisades and the puddingstone from lower or middle Paleozoic conglomerates such as the Green Pond Conglomerate found near the New York-New Jersey border northwest of the Palisades.

STOP 6. At the actively slumped section in the topographic high in the bluffs.
The increased elevation of the bluffs is due to the thickening to about 8 m of the fine grained bedded sediments above the till. These stratified layers exhibit small scale cross bedding and bedding rippled by translational waves overturned to the southeast. This unit is characterized by clay, silt, and fine sand at the base which is somewhat obscured by slumping. It coarsens upward into fine and medium sized sand. Overall this unit probably represents sedimentation in a proglacial lake that formed between the ice just to the north and the upland to the south. Eastward across the bay in Eatons Neck, a well defined, horizontal band is visible in the bluffs. This dark layer also consists of proglacial lake sediment that overlies Cretaceous sand, but at a somewhat higher elevation than the lake beds at Lloyd Neck. The proglacial lake deposits are seen as evidence of the "Necks" stillstand during the recession of the late Wisconsinan glacier. A marked increase in cobbles in the loess layer and a thin stone layer on the stratified sands also appears in this section. Between Stops 2 and 3 the elevation of the bluffs decreases and the lake sequence becomes thinner. Also, the dark silty base of the lake deposits becomes visible and minor deformational features begin to appear in the overlying sediments. The surface unit has coarsened and also shows evidence of deformation, mainly small thrusts displaced southward. At one point a sizable granitic boulder in this unit has been rotated to the southeast. This evidence suggests southeastward movement of ice that overrode and deformed this section. On the beach a number of predominantly dark colored erratics of mafic composition have been eroded from the till. Some of these rocks resemble the Harrison Gneiss found to the north and northwest in southern Westchester and Connecticut.

Stop 7.
This stop is separated into two parts, 7A and 7B. Stop 7A (Fig. 5B) is in the low cliff where well exposed lake silts may be observed. Here the basal unit of interbedded, fine grained silts and sands are well exposed. These beds are somewhat disturbed and have small folds that are overturned to the southeast, and represent additional evidence of minor glacial deformation due to overriding by the ice.
STOP 7B is just to the northwest of Stop 7A.
The lake beds pinch out between these stops and the coarsened cobble unit rests directly on the compact (lodgment?) till. The rapidly changing nature of the upper unit is apparently the result of changing levels of energy of nearby ice and meltwater from the ice. It may have been emplaced as a till or ground moraine or as a head of outwash. Alternatively, this layer could be a colluvium or a lag deposit developed after the ice receded. Thus this unit seems to exhibit a combination of glacial, glacio-fluvial, or postglacial erosional characteristics. Clearly, deposition occurred near the glacial margin and some glacial overriding is indicated in the minor deformational features. When the ice stood along the northern edge of Lloyd Neck, tongues of ice may have extended southward into Huntington Bay. Till was deposited at the ice front, and outwash, colluvium and lacustrine sediments accumulated on the upland south of the ice and in and around proglacial lakes. Minor fluctuations of the ice resulted in the minor deformational features and in the sorting of the gravel layer.

STOP 8. The low cliff at the northern point of the beach.
The till-like character of the upper unit is more apparent in this section where it rests directly on the lower till. Pronounced thrusts and complex folds or convolutions occur along the contact between the beds. The more felsic nature of the erratics seen on the beach is in marked contrast to the rocks on the beach to the south.
This upper till is of limited extent and seems to grade southward into proglacial deposits. It was probably deposited during the "Necks" stillstand, with a different source area than the underlying till. While correlation with other local tills has not been resolved, the lower till at Lloyd Neck may be the equivalent of the upper or late Wisconsinan till (the Roslyn Till) in Port Washington. The differing source areas between the two (possible) late Wisconsinan tills may be due to their interlobate position and the stacking of Hudson Valley and Connecticut lobe deposits as the ice front fluctuated.
The following sequence of events is postulated for deglaciation in this region.
1. Late Wisconsinan ice downwasted, thinned and gradually receded northward from the terminal moraine.
2. As the ice receded minor lineations of surficial deposits and meltwater channels developed, marking ice marginal positions.
3. When the ice reached the northern margin of the necks, a major stillstand occurred. Meltwater cut east-west drainage channels such as Lloyd Harbor.
4. Ice tongues expanded into and excavated U-shaped valleys where the bays are today. Kames on the proximal slope of the Harbor Hill moraine mark the southward extent of this re-advance.
5. As the ice receded, proglacial sediments, outwash and colluvium were deposited. Lacustrine sediments accumulated in proglacial lakes dammed between the ice and the upland. Minor fluctuation of the ice deformed these sediments but on a much smaller scale than the deformation observed at Port Washington which was related to the main advance of the Late Wisconsinan glacier.
6. Recession of the ice from the "Necks" position formed other minor lineations observed in the position of small islands of glacial deposits in the Sound and minor moraines in Westchester and Connecticut.

FIELD GUIDE BOOK
VASSAR COLLEGE POUGHKEEPSIE, NEW YORK OCTOBER 15-16, 1976
The organizer of the field trips described in this volume, and of the meeting at which they were given, is
Professor John H. Johnsen, Chairman
Department of Geology & Geography
Vassar College
Poughkeepsie, New York 12601
Copies of this guidebook may be purchased the Executive Secretary of the New York State Geological Association: Dr. Daniel F. Merriam, Chairman Department of Geology, Syracuse University, Syracuse New York 13210.
Frontispiece -A. Scott Warthin Jr., Professor Emeritus of Geology, Vassar College, dean of Hudson Valley Geologists and expert on Dutchess County geology, examining block of Wappinger dolostone in deformed Snake Hill Shale, visible between Stops 3 and 4 on Trip 8-6, south side of Spackenkill Road near Cedar Valley Road.
Photograph by Donald W. Fisher, 1975.
The area surrounding Vassar College provides a wealth of material for the geoscientist. It's classic ground in the study of geology -the Taconics, Hudson Highlands, Shawangunks, Catskills and the Hudson Valley each provide wonderful and exciting outdoor classrooms. Because most major rock types lie within one or more of these areas, it was possible to schedule a number of excursions into igneous, sedimentary and metamorphic terrains which exhibit simple to intensely deformed structures as well as geologically-oriented trips related to recent environmental concerns in part brought on by the presence of these structures. Each of the leaders invited to participate is either involved in current field research or has had a great deal of recent field experience within the area of his trip so that much new significant data heretofore unpublished are made available in this guidebook. The field program is sufficiently diverse in locale and content to provide something of interest for everyone.
To celebrate the Bicentennial of our country, we depart from tradition by offering a limited enrollment extra-cost trip on the Hudson River from New York City to Poughkeepsie on the first day of the meeting to view the geology along its east and west banks and to learn something of the colonial and revolutionary history that was made along its course and, on the final day, a walking trip through historic Fishkill, New York. A separate guidebook has been prepared for the participants of the river trip, but a limited number will be available for sale. In addition, the Lamont-Doherty Geological Observatory at Palisades, New York, will host an open house on the first day of the meeting to provide an opportunity for members of the New York State Geological Association to tour the facilities and meet with a number of the scientists conducting research there.
Lack of secretarial assistance and increased costs made it impossible for articles to be retyped on the same machine. By prior mutual consent, each author agreed to use one of several similar type styles and to review their manuscripts before submission. No editorial changes were made.
The Editor wishes to express his thanks, on behalf of the NYSGA, to Vassar College for serving as host to its 48th Annual meeting, to each of the authors who graciously accepted full responsibility for organizing and leading his trip, to A. Scott Warthin Jr., who ably took over the reins for me during the summer of 1976 while I was on the other side of the world and to those colleagues and majors in my department that gave so generously of their time.
Welcome to Vassar College and the historic Mid-Hudson Valley. We hope you thoroughly enjoy your brief study of this region.
John H. Johnsen Editor

B1: STRUCTURE, PETROLOGY ANO GEOCHRONOLOGY OF THE PRECAMBRIAN ROCKS IN THE CENTRAL HUDSON HIGHLANDS
Henry L. Helenek
Bradley University
Peoria, Illinois 61625
Douglas Mose
George Mason University
Fairfax, Virginia 22030
Recent studies in the New York portion of the Reading Prong indicate that the Hudson Highlands may consist of two terranes of Precambrian rock (Harwood and Zietz, 1974; Hall et al., 1975). A western terrane consists of charnockitic gneisses and paragneiss intruded by syntectonic granitoid plutons. An eastern terrane consists of quartzo-feldspathic gneisses having lithic and structural similarities with the Fordham gneiss immediately to the south in Westchester County (Hall et al., 1975). Fundamental differences in lithology, structure, geochronology and magnetic signature have been summarized by Harwood and Zietz (1974) and Hall et al. (1975). Although the position and nature of the contact separating the two terranes remains problematical, an approximate boundary may be placed in the vicinity of the Ramapo-Canopus fault system in the Hudson Highlands. Detailed study is needed to establish the relationship between the two suites of rock. The purpose of this field trip is to examine the structure, petrology and geochronology of Precambrian rocks at select sites in both terranes. The Lake Carmel area in the eastern Highlands (stops 1 and 2) and the West Point area in the western Highlands (stops 3, 4, 5, 6, 7, 8) have been chosen for this purpose.

B1: STRUCTURE, PETROLOGY ANO GEOCHRONOLOGY OF THE PRECAMBRIAN ROCKS IN THE CENTRAL HUDSON HIGHLANDS

Exposures of the Wappinger Group are seen on both sides of the road.

Normanskill formation and Austin Glen formation
This low-lying area of sparse outcrop is underlain by autochthonous Middle Ordovician clastic rocks (Normanskill formation and Austin Glen formation).

Austin Glen formation on left
Exposures of autochthonous Middle Ordovician rocks (Austin Glen formation) on the left side of Route 9.

Austin Glen formation on right
Exposures of autochthonous Middle Ordovician clastic rocks (Austin Glen formation) on right side of Route 9

Glenham gneiss belt.
Exposures of sheared Precambrian gneisses and the Wappinger Group along both sides of Route 9.

Precambrian gneiss
To the left is Honness Mtn. Exposures of Precambrian gneiss.

Poughquag quartzite
Toward the left in the westbound lane of I-84, are exposures of Poughquag quartzite.

Exposures of lower members of the Wappinger Group on both sides of I84.

Gently folded syncline on left Highlands on right
Gently folded syncline in the Wappinger Group on the left (north) side of 1-84. The Hudson Highlands are seen to the right (south).

Exposures of lower members of the Wappinger Group.

Ramapo fault
The prominent valley to the right (south) is an extension of the Ramapo fault through the Hudson Highlands.

Large exposures of Precambrian gneiss.
Biotite granitic gneiss predominates with subordinate amphibolite and hornblende biotite granite gneiss. Rocks have varying degrees of cataclastic deformation. Minerals are partially altered. Toward the eastern end of the exposure is in-folded Poughquag quartzite.

Large exposures of Precambrian gneiss.
Predominant rocks are biotite-quartz-plagioclase gneiss and quartz-plagioclase leucogneiss with subordinate amphibolite, biotite-hornblende-quartz-plagioclase gneiss and pyroxenite. All minerals are partially altered and replacement textures common.

Large exposures of Precambrian gneiss.

View of Hudson Valley
Toward the left (northwest) is a spectacular view of the Hudson Valley.

Large exposure of Precambrian gneiss.
Precambrian rocks from this point to stop 1 consist of biotite-quartz plagioclase gneiss, biotite-hornblende-quartz-plagioclase gneiss, amphibolite and biotite-muscovite-quartz-plagioclase gneiss.

Sampling locality for Rb/Sr whole rock dating
Large exposure of light gray, biotite-muscovite-quartz-plagioclase gneiss. Sampling locality for Rb/Sr whole rock dating (1296 ± 77 m.y.).

Large road cut of Precambrian amphibolite.

STOP 1. Mill Pond Garden Center.
(No hammers, please!)
Exposure of light gray, biotite-muscovite-quartz-plagioclase gneiss. This foliated gneiss is one of the most important lithologies in the eastern Hudson Highlands. The exposure seen here is on strike with the large roadcut of light gray gneiss on I-84. In the I-84 outcrop. the biotite-muscovite-quartz-plagioclase gneiss contains bands consisting of biotite-actinolite-plagioclase gneiss. Foliation trends about N40°E and is almost vertical. The light gray, biotite-muscovite gneiss is among the oldest rocks found in the Hudson Highlands and yielded a Rb/Sr whole rock age of 1296 ± 77 m.y, with an initial 87Sr/ 86Sr ratio of 0.7032 ±0.0005.

Exposures of Precambrian rock.

Walloomsac formation
Exposures of metamorphosed Middle Ordovician clastic rocks (Walloomsac formation).

STOP 2. Forest Haven Apartments.
A short traverse will be made through the upper pЄ ga unit and the lower pЄ lg unit.(No hammers, please!)
Station A. pЄ lg unit. Exposures of layered, medium-grained, mesocratic biotite hornblende-quartz-plagioclase gneiss. Prominent F2-folds have axial planes trending about N40°E, 60°S. Fold axes plunge about S70°E at 60° but marked variability from this direction is noted. Abundant crenulation folds are related to F2-folds.
Station B. pЄ ga unit. Leucocratic granitic gneiss forms large domical exposures. Amphibolite with calc-silicate nodules defines a large F2-fold.
Station C. pЄ lg unit. Exposures of layered biotite-hornblende-quartz-plagioclase gneiss. Prominent F2-folds have axial planes oriented N-S, 55°E; folds plunge N58°E at 34°. The change in orientation of F2-axial planes from station A is a result of F3 folding.

Rb/Sr whole rock age of 1308
About one mile to the south, samples of a granite gneiss yielded a Rb/Sr whole rock age of 1308 ±41 m.y.

To the right (south) is the Tilly Foster Mine.

Large roadcut to the right
Geology of the large roadcut to the right described by Fenster and Brock, 1975.

Large preCambrian exposures
Large exposures of the pЄ q unit and the pЄ lg unit.

Large exposure
Large exposure of the pЄ ga unit. This roadcut is described in detail in Hall et al. (1975).

Contact between ga and am units
Exposures of the contact between the pЄ ga unit and the pЄ am unit.

Far lane has exposures of bg unit
To the left in the eastbound lane of 1-84 are exposures of the pЄ bg unit.

Whole Rock date 1296
Exposure on the left is a sampling locality for Rb/Sr whole rock dating (1296 ±77 m.y.) of the biotite-muscovite-quartz-plagioclase gneiss.

Whole rock age 1296
Exposure on the left is a sampling locality for Rb/Sr whole rock dating (1296 ±77 m.y.) of the biotite-muscovite-quartz-plagioclase gneiss.

Exposures of paragneiss on the right side of Route 301.

Entering the Ramapo-Canopus fault zone.
Note sheared rock on both sides of road.

Canopus Lake.
The Ramapo-Canopus fault roughly trends along the axis of the lake.

Whole rock age 914
Exposure on the right is a sampling locality for Rb/Sr whole rock dating (914 ±31 m.y.) of the Canada Hill granite.

Whole rock age 914
Exposure to the right of the road is sampling locality for Rb/Sr whole rock dating (914 ±31 m.y.) of the Canada Hill granite.

Site of the Robinson House on the left.
Site of the Robinson House on the left. Benedict Arnold secretly offered the British the surrender of West Point and settled the particulars in a midnight meeting with Major John Andre in the Robinson House on Sept. 21, 1780. Andre was captured two days later and hanged at Tappan, Oct. 2, 1780. Arnold made his escape to the British sloop, Vulture.

Prominent landform to the left is Sugarloaf Mountain.

Eastern anchor for chain across Hudson
Eastern anchor for the chain across the Hudson River which failed to prevent British ships from sailing up the Hudson River during the War of Independence.
2013: Historic marker here says "The first chain, planned to keep British ships from going up river anchored on shore below, was forced by the enemy, Oct. 7, 1777"

Bear Mountain and the Torne
The large mountain straight ahead and to the left is Bear Mountain. The prominent knob straight ahead and to the right is the Torne.

STOP 3. Bear Mountain.
Stop 3 is a short walk north of Bear Mountain Inn to the roadway north of Hessian Lake (Fig. 3). The exposures that will be studied at this locality are in Harriman State Park and regulations prohibit destruction of the environment in any way. (NO HAMMERING PLEASE!)
Several lithologies typical of the western Highlands terrane are seen in these exposures. These include the paragneiss (pЄ pg) with its associated amphibolite and rusty pyroxenic gneiss (pbЄ pga) and foliated hornblende granite (pЄ sk). Canada Hill granite (pЄ ch) cross-cuts structures in all three lithologies. These units form the lower limb of a reclined isoclinal F2 antiform (Ft. Montgomery antiform).
pЄ pg, pЄ ga and pЄ sk are folded into isoclinal digitations and compositional layering is completely transposed into an F1 axial planar foliation. F2-folds are locally similar in style and are usually more open than F1-isoclinal folds. Several minor F2-folds occur in the hornblende granite at this locality. A hornblende lineation best seen in the amphibolite (pbЄ ga) trends about N37°E at 37° and is parallel to fold axes of F2-folds. The broad curvature to the units in the Bear Mountain area seen on the map (Fig.3), is due to F3-folding. Fold axes of F3-folds plunge N50°E at 36° in this area.
The deformation seen in the hornblende granite at this locality is absent in the main mass (core) of hornblende granite at Bear Mountain. However. a strong hornblende lineation in the core granite parallels the hornblende lineation in the amphibolite (pЄ pga) of the paragneiss unit (pЄ pg). Since marginal gneissic facies of the hornblende granite locally possess secondary foliation related both to D1 and D2, the Bear Mountain pluton has been involved in all phases of deformation. The Rb/Sr whole rock age of 1086 m.y. and the U/Pb age of 1060 m.y. obtained from the lineated core facies of the pluton probably indicate the time of crystallization of residual melt in the Bear Mountain pluton. This would suggest that final crystallization of the hornblende granite was coeval with the termination of F2-folding in the West Point area.
The coarse-grained, leucocratic Canada Hill granite cross-cuts linear and planar structures in the granite-gneiss sequence and contains inclusions of pЄ sk and pЄ pga (the latter not seen in these exposures). In other localities where the hornblende granite and Canada Hill granite are in close proximity, the relationship between the two granites is at best equivocal. Field relationships seen at these exposures clearly demonstrate the crosscutting nature of the Canada Hill granite. This, combined with a Rb/Sr whole rock age of 914 m.y., supports the assignment of a post-Storm King age to the Canada Hill granite. The crystallization of Canada Hill granite represents the termination of Grenville activity in the Hudson Highlands.

Bridge over Popolopen Brook (also known as Hell Hole).

Fort Montgomery
To the right of the road is the site of Fort Montgomery, prominent in the American Revolution.

Canada Hill granite
Exposures of Canada Hill granite in the core of the Crystal Lake pluton.

Large exposure of hornblende granitic gneiss.
Large exposure on the left side of Route 9W is hornblende granitic gneiss. This is an extension of the Bear Mountain pluton and forms the core of the West Point antiform.

Core of the West Point antiform
On the left side of the road are exposures of paragneiss in contact with hornblende granitic gneiss in the core of the West Point antiform.

STOP 4. Northern margin of the Crystal Lake pluton.
The next two stops will illustrate field relationships between the paragneiss unit (pЄ pg) and the Canada Hill granite (pЄ ch) by taking a cross sectional traverse through the Crystal Lake pluton. Canada Hill granite is found in several zoned plutons restricted to the paragneiss unit, the largest of which is the Crystal Lake pluton. Stop 4 is located at the northern margin of the pluton; stop 5 is located in the core of the pluton. In traversing the Crystal Lake pluton from margin to core, we will proceed from non-migmatitic paragneiss, through a marginal zone of migmatite (metatexite of Mehnert, 1968) into a core of diatexite (a rock characterized by "complete or nearly complete melting no longer be distinguished", Mehnert, 1968, p. 253). The following lithologies make up the Crystal Lake pluton and its enclosing rocks:
Non-migmatitic paragneiss is an equigranular rock with a metamorphic fabric containing quartz, plagioclase feldspar, microcline, biotite and garnet. Quartz, microcline and plagioclase feldspar are present in about equal amounts.
Migmatite consists of leucosome and melanosome. Leucosome is a coarse-grained, inequigranular rock containing quartz, microcline, plagioclase feldspar and biotite with or without garnet. In mineralogy, leucosome is similar to diatexite. Melanosome is finer and more even grained than leucosome and consists of varying proportions of quartz, plagioclase feldspar, biotite, garnet and occasionally sillimanite. Alkali-feldspar is minor or absent.
Diatexite is a coarse-grained, inequigranular rock consisting of quartz, slightly perthitic microcline, plagioclase feldspar (calcic oligoclase) and varying amounts of garnet and biotite. Sphene and zircon are ubiquitous accessory minerals; sillimanite, graphite and tourmaline are rare. Two facies of diatexite occur in the Crystal Lake pluton: homophanous diatexite (a homogeneous granite) and schlieric diatexite (homogeneous granite with schlieren of restite). Alteration related to crystallization of diatexite resulted in the formation of secondary muscovite and epidote and the alteration of biotite.
The Q:Ab/Pl:Or and mineralogical ratios for these rocks are plotted in figure 5. The normative Q:Ab:Or ratio of diatexite lies in the field of igneous plutonic rocks containing 80% or more normative quartz-albite-orthoclase (Fig. SA). These data support a magmatic origin for the diatexite facies of the Canada Hill granite. The normative Q:Ab:Or ratio of leucosome in migmatite likewise lies in the field of magmatic rock. Mineralogical data for Canada Hill granite (diatexite), migmatite and non-migmatitic paragneiss are plotted in figures 5C and 5D. The composition of Canada Hill granite and leucosome is virtually identical. The homogenized composition of leucosome-melanosome pairs approximates the mineralogical composition of non-migmatitic paragneiss. These data indicate that non-migmatitic paragneiss represents paleosome from which migmatite and Canada Hill granite formed by anatexis.
Isotopic studies also support an anatectic origin for the Canada Hill granite. Paragneiss yielded a Rb/Sr whole rock age of 1139 m.y. with an initial 87Sr/86Sr ratio of 0.7067. The Canada Hill granite (diatexite) yielded an age of 914 m.y. and an initial ratio of 0.7193. The data also show that the average 87Rb/86Sr ratio of the paragneiss is 3.8. If the paragneiss remained a closed chemical system between 1139 m.y. and 914 m.y. ago, its average 87Sr/86Sr ratio would have ranged from 0.7067 to about 0.7118. A calculated ratio of about 0.718 is essentially the same (given the error) as 0.7193, the initial 87Sr/86Sr ratio of the 914 m.y. old Canada Hill granite. This indicates that the paragneiss anatectically yielded a granitic melt in an isotopically non-fractionating manner which crystallized at about 914 m.y. ago to form Canada Hill granite.
Station A. Leave the parking area and proceed to Route 970/Main St. Turn right onto Route 970/Main St. and walk to large outcrop of the non-migmatitic paragneiss on the east side of the road.
Proceed down Route 970/Main St. in the direction of the parking area. Continue south past Station Hill several hundred feet to Michel's Gift Shop. Bear left off Route 970/Main St. and proceed down gravel road passing through the nursery (this gravel road is known as Wood Lane). Proceed to the end of Wood Lane past three private houses to the large exposure overlooking the Hudson River.
Station B. Large exposure of migmatite and Canada Hill granite. No hammers, please!

STOP 5. Canada Hill granite (diatexite)
Large roadcut exposing the schlieric facies of Canada Hill diatexite.

Core of West Point Antiform
Hornblende granitic gneiss in the core of the West Point antiform is seen to the left.

On left is paragneiss
Large roadcut to the left is paragneiss (pЄ pg).

Hornblende quartz monzonitic gneiss
To the right is an exposure of a thin sheet of hornblende quartz monzonitic gneiss (pЄ sk).

STOP 6. Magnetite alaskite.
Magnetite alaskite (pЄ al) is a late to post-tectonic plutonic rock occupying a narrow fault-controlled valley between the Crows Nest antiform and West Point synform. Alaskite is a medium-to coarse-grained, massive rock consisting of quartz (21 %), white plagioclase feldspar (41 %), pink microcline (35%) and magnetite (3%). Secondary minerals include muscovite, sericite and opaque oxides. Inclusions of country rock and xenocrysts derived from the country rock are common in the marginal facies of the alaskite. Recrystallized biotite inherited from the adjacent paragneiss is seen in this exposure of alaskite. A fracture cleavage is commonly developed in alaskite.
The relationship of alaskite to other Highlands lithologies remains uncertain. While it intrudes pЄ qp, pЄ pg and pЄ sk. its relationship to Canada Hill granite is not at all clear. The fracture cleavage in the alaskite may be related either to D3 or to some post-D3 deformational event. The lack of any penetrative structures related to D1 and D2 however, indicates the alaskite was intruded late in the deformational history.

Charnockitic quartz-plagioclase gneisses
To the left are large exposures of charnockitic quartz-plagioclase gneisses (pЄ qp), Coarser grained, massive rock is the alaskite which intrudes the quartz-plagioclase gneisses.

STOP 7. Crows Nest Lookout.
View of the Hudson River. Constitution Island and the United States Military Academy at West Point. The ridge southwest (to the right) of the Military Academy is held up by a thin sheet of hornblende quartz monzonitic gneiss. The hornblende granitic gneisses are the most resistant of the Highlands lithologies to weathering and are the major ridge formers in the Hudson Highlands. The quartz monzonitic gneiss at West Point forms a prominent ridge which outlines the structure of the West Point antiform. The fold axis of this antiform plunges N36°E at 22°; the axial plane is oriented N30°E, 74°S. The valley at the base of the Crows Nest is underlain by magnetite a1askite.
The Crows Nest lookout is situated along the southeastern limb of the Crows Nest antiform. Exposures of hornblende quartz monzonitic gneiss surround the lookout. The foliation in the gneiss is an F2 axial planar foliation oriented N45°E. 70°N. This foliation is continuous with a secondary foliation described by Murray (1965) in the crest of the Crows Nest antiform at Bull Hill. The hornblende quartz monzonitic gneiss forms the core of the Crows Nest structure and yielded an Rb/Sr whole rock age of 1169 m.y. The Crows Nest antiform plunges N43°E at 18°; the axial plane is oriented N60°E, 45°N. A prominent mineral lineation trends N40°E at 22°.
On the far side of Route 9W across from the lookout, a basic dike (orientation, N75°W, 62°S), about 90 feet thick, cuts the trend of the Crows Nest fold. Undeformed basic dikes are plentiful in the Highlands and parallel the dominant joint directions in the Highland gneisses. The majority of dikes are lamprophyric or diabasic; dioritic and andesitic as well as dikes consisting of syenite and quartz porphyry are less common. The age of these dikes is uncertain.

Core of the Crows Nest antiform
Exposures of hornblende quartz monzonitic gneiss in the core of the Crows Nest antiform.

To the left is a shear zone
To the left is a shear zone separating the Crows Nest block from the Storm King block.

Crest of Storm King Mountain
Large hill of bedrock to the right is the crest of Storm King Mountain (Butter Hill, elevation 1380 feet) underlain by hornblende granitic gneiss.

STOP 8. N. border fault of the Hudson Highlands.
Hornblende granite thrust adjacent to Ordovician clastic rocks. The trace of the fault on the map trends about N35°E. Berkey (1910), however, reported an orientation of N70°E, 45°S for the fault plane based on subsurface data obtained from the Catskill aqueduct project. The question arises as to whether the northern border fault is a high angle thrust fault or a low angle overthrust. A short distance southeast of this locality, Lowe (1958) reported overthrusting of Storm King granite over intensely crumpled Ordovician slaty shales. Further to the southeast (1400 feet southeast of this stop), Berkey (1910) noted that sheared hornblende granite was penetrated to a depth of 412 feet in a series of drill holes in Pagenstechers Gorge (ravine along Mountain Rd.). A tunnel bored across the Hudson River in 1912 from Storm King Mountain to Breakneck Ridge at a depth of 1100 feet and two inclined drill holes across the Hudson in the same area intersecting at a depth of about 1500 feet, both penetrated hornblende granite beneath the Hudson River (Kemp, 1912). These data would appear to suggest that the northern border fault of the Hudson Highlands is a high angle thrust fault with local overthrusting.

Museum of the Hudson Highlands.

Hornblende granite gneiss on both sides of the road.

Hills off to the right are the Hudson Highlands.

Washington's HQ to right
To the right is a road leading to Washington's headquarters in Newburgh (1782-83).

Cross the Beacon-Newburgh Bridge.
To the right (south) is a spectacular view of the northern passage of the Hudson Highlands. On the right is Storm King Mountain. On the left is Beacon Hill-Breakneck Ridge. The small island in the Hudson River is Pollepel Island.

Hornblende granite in the Glenham gneiss belt.

Wappinger Group with Balmville limestone
Exposure of the upper members of the Wappinger Group with conglomeratic Middle Ordovician Balmville limestone.

B2: STRUCTURAL GEOLOGY OF THE TACONIC UNCONFORMITY
Heinrich Toots
C. W. Post College
Long Island University
Greenvale, N.Y.
The Hudson Valley is one of the classical areas of North American geology. One of its most prominent geological features is the Taconic unconformity separating the Ordovician and Cambrian sediments from the overlying Silurian and Devonian strata. The Taconic unconformity records the earlier of two (or possibly three) Paleozoic orogenies in the Hudson Valley. The Taconic unconformity has been known since the first half of the nineteenth century and its significance for stratigraphy and the geologic history of eastern North America has been discussed by many authors (Davis, 1883a, Schuchert and Longwell, 1932, Rodgers, 1971). It is a favorite subject of textbooks of historical geology which often illustrate and discuss the relationships displayed at the unconformity for example Dunbar and Waage, 1969, Figs. 9-8 and 9-9, Kay and Colbert, 1965, p. 174, 214).
By contrast, the structural significance of the Taconic unconformity has received little attention. The entire subject of deformation of unconformities has been neglected in comparison to its structural importance. The numerous existing studies of multiple deformation deal mainly with superimposed folding deep in the basement complex and very few of them take into account what happens at or near unconformities. Textbooks in structural geology often do not even mention the subject. The field trip area offers excellent opportunities to study the effects of folding of an unconformity and the underlying as well as overlying rocks. The plan of the field trip is to start by inspecting the formations involved in places where the structure is simple and then to proceed to outcrops at which folding of the unconformity has complicated the structures.
The present field trip is an outgrowth of class field trips I have conducted for my structural geology class. It is based on study of easily accessible outcrops that are particularly instructive by virtue of the major and minor structures they exhibit. Study of these outcrops has been carried only to the point of developing a conceptual scheme to explain the structures visible. Thus identification of formations is in some cases still tentative and I have made no attempt to record attitudes on an areal basis. Thus much work remains to be done and the field trip area should be a highly rewarding subject for one or more studies of structural details. It is difficult to find two unconformities in which the geometry of the older structures and the mechanical properties of the rocks are exactly alike at the time of the second deformation and the general principles of multiple deformation apply here to a unique array of structural details.

B2: STRUCTURAL GEOLOGY OF THE TACONIC UNCONFORMITY

Start of a long road-cut in Austin Glen Graywacke.

Erratic Boulder
Note large erratic boulder in road-cut on left side.
2013: No longer there, according to StreetView.

STOP 1. Austin Glen Graywacke.
Beds of sandstone and shale in the Austin Glen Graywacke exhibit here very regular structures indicating that only one orogeny produced major deformation in this locality. Good slaty cleavage developed in shaley layers.

Slate in road cut.

Small shale road cuts for next two miles
For next two miles there are several small road cuts in shale (possibly Snake Hill).

Gently deformed Austin Glen
Outcrops of Austin Glen Graywacke show only gentle deformation.

STOP 2. Two roadcuts in the Austin Glen Graywacke
Two roadcuts in the Austin Glen Graywacke show some of the variations in lithology in the unit. Again the structure is very simple, suggesting that the Taconic orogeny had little effect at this locality.

Gravel pits on left side of road.

Roadcut in Onondaga Limestone.

Onondaga Limestone exposures
For next mile outcrops of Onondaga in roadcuts and in back buildings.

Road cut in Esopus and Schoharie Formations.

STOP 3. Anticline
Anticline in Lower Devonian Becraft, Alsen and Port Ewen formations exposed in roadcut on both sides. The regular curvature for the formations is characteristic of flexural slip folding where there are not complications caused by the underlying rocks.

Road cut in Coeymans, Kalberg and New Scotland formations

STOP 4. The Austin Glen Graywacke
The Austin Glen Graywacke forms the bottom part of the outcrop at the north end. It is unconformably overlain by the Rondout Formation but the unconformity itself is not well exposed because of weathering of the contact. A number of faults cut through the limestones above the unconformity. Their presence lets one to expect massive graywacke underneath the unconformity.

STOP 5. Outcrop of Taconic Unconformity
One of the best outcrops of the Taconic unconformity in the Hudson Valley.
In places the unconformity is torn open into a tension gash and occupied by a quartz vein. Walking a short distance south along the outcrop one can see numerous slickensided shear fractures, blocks of shale displaced along curved or irregular shear fractures and rotated as a result so that the directions of the slaty cleavage vary in the outcrop. Note the contrast between the highly complex and irregular structure in this outcrop and the very simple and regular structures at Stops 1 and 2.

STOP 6. Sharp flexure in Schoharie Formation.
It probably lies in the continuation of a fault separating relatively large rigid blocks below the unconformity.

STOP 7. Long roadcut.
A variety of structures can be observed on the north side of the highway. A series of folds including chevron folds and isoclinal folds in a predominantly graywacke unit has moved as a single rigid block. It is in fault contact with a predominantly shaley sequence that is intensely sheared so that the original continuity of the beds is destroyed. Tension gashes can be seen cutting some graywacke beds. Shale layers in the chevron folds are greatly thickened in the hinges by flow folding. Some graywacke layers exhibit sole markings at their bottom.

Folds in Austin Glen Graywacke.

Roadcuts in Austin Glen Graywacke.

Note quartz veins in outcrop at right.

STOP 8. Intensely sheared shale and graywacke.
In places the strata have been turned virtually into a tectonic breccia with an appearance resembling a melange. Note slivers of graywacke floating in a shale matrix. The direction of the slaty cleavage is variable. Close study is needed to determine whether two intersecting directions of cleavage actually exist or whether different slices of shale have been rotated out of their original position.

B3: STRATIGRAPHY AND PALEONTOLOGY OF THE BINNEWATER SANDSTONE FROM ACCORD TO WILBUR, NEW YORK
Russell H. Waines
State University of New York College at New Paltz
The Binnewater Sandstone was first recognized as a stratigraphic unit by Hartnagle (Binnewater quartzite, 1905, p. 346). It has long been recognized in outcrop within a narrow, structurally complex belt extending nine miles southwest from Wilbur (just south of Kingston) to High Falls. In addition, the Binnewater Sandstone has been recognized in boreholes just west of High Falls (Berkey, 1911, p. 132), near Accord (Port Jackson) (Johnsen and Waines, 1969, p. 30) and near Wawarsing (Bird, 1941, p. 276-278). These borings are located eight tenths, six and twelve miles southwest of High Falls respectively so that the total linear extent of the Binnewater as presently recognized is about twenty-one miles.
The Binnewater Sandstone thickens progressively from Wilbur where 4.3 feet have been measured on the east bank of Roundout Creek to about thirty feet in the Rosendale area to about forty feet at High Falls to about sixty at Accord. Bird's stratigraphic columns for Wawarsing (1941, p. 276-278) indicate 125 or 170 feet depending on the scale of the column used. According to his lithologic descriptions the thickness is more likely 85 or 105 feet. In addition, the scale in his column on page 278 seems to be in error. North and east of Wilbur the Binnewater has apparently been removed by pre-Rosendale erosion.
The lithology of the Binnewater is variable. From High Falls northeast to Wilbur it is predominantly a slightly dolomitic, fine to medium-grained quartz arenite with sparse interbeds of dolomitic shale and argillaceous dolostone. Southwest from High Falls interbeds of dolomitic shale and argillaceous dolostone tend to increase at the expense of the sand content. Non-sand content increases southwest from High Falls to Accord to Wawarsing from about five to fifty to apparently seventy per cent.
The sandstones of the Binnewater are generally dark grey to light grey to white, weathering orange to buff to grey to white. Increase in dolomite content is attended by an increasingly orange to rusty appearance when weathered. Shales and dolostones within the Binnewater may be dark grey to light grey-green. Again, increasing dolomite content is accompanied by an increasingly darker rusty color. Distinct red coloration more typical of the High Falls Shale may occur in sandstones, shales or dolostones and varies from traces at High Falls to about 15 per cent in drill core at Accord to perhaps as much as 30 per cent at Wawarsing.

B3: STRATIGRAPHY AND PALEONTOLOGY OF THE BINNEWATER SANDSTONE FROM ACCORD TO WILBUR, NEW YORK

Bridge over Wallkill River.

STOP 1. Complete exposure of Binnewater Sandstone
Complete exposure of Binnewater Sandstone can be seen at this stop; including upper contact with Rosendale Dolostone, upper massive sandstone unit, poorly developed underlying shale unit, main cross-laminated sandstone unit, lower shale unit, bottom dolostone breccia unit and possible lower contact with the High Falls Shale. Cross-laminations, ripple marks and desiccation cracks can be observed in the middle unit. Casts of salt hoppers have been found in the upper part of the middle unit and will be displayed in the Geology Department at Vassar College at the conclusion of this trip. Studies of cross-laminations by Ringler (1970, 1971) and of sand grain orientations by Fields (1975a, 1975b) indicate a preponderant net shift of sediment to the northwest (N36°W) with a statistical allignment of long axes of sand grains (N80°E-S80°W). This may indicate that the bulk of the sand grains progressed northwestward as "rollers" rather than as "sliders". A tidal flat environment is proposed for most of this section.
Caution -This road cut has become increasingly unstable over the years. Watch out for falling rocks and blocks!

Bridge over Rondout Creek.

Lefever Falls below to the right
Lefever Falls below to the right has been somewhat modified by the U.S. Army Corps of Engineers.

Park on loading platform
At bottom of hill after passing through a descending left-hand curve park on loading platform on the right. This platform once served barges berthed in a turning basin of the Delaware and Hudson Canal. The canal was last used around the turn of the Century.

STOP 2. Lefever Falls Mine
Caution - Please do not fall into the mine as accidents will impede the progress of this field trip and we are on a tight schedule! Do not crowd one another near the edge of the mine!
A nearly complete section of Binnewater Sandstone can be seen at this stop in the southwest wall of the mine entrance. It is not as well exposed as that in STOP 1 due to cover by mosses and lichens. The upper massive sandstone has been removed by pre-Rosendale erosion. The shale beneath is not exposed but can be seen several hundred feet to the south on the dip slope of the top surface of the main sandstone unit. The contact between the Shale and the overlying Rosendale Dolostone can be observed in the vicinity only with difficulty. The lower shale unit and the bottom argillaceous dolostone unit can be observed on both the north and south walls of the mine entrance. Pass through the archway in the wall on the left (south) and proceed with care past the steeply dipping mine opening on the right. Your first slip may be your last. Continue south for several hundred feet with the dip slope of the main sandstone unit on your left. Where possible, examine the slope for signs of silicified, hemispherical stromatoporoid coenostea in growth position. Should you find one please do not collect it as our studies of this location are not completed. Continue south until the upper shale unit is reached and can be examined. The significance of this locality is discussed in the text.

STOP 3: A complete section of Binnewater Sandstone
Sandstone can be seen with all units as at STOP 1 but the upper dolomitic shale unit is much more clearly defined. The relief on the top of the upper massive sandstone unit can be seen on the dip slope of the floor of the mine where the overlying Rosendale Dolostone has been removed. The Binnewater-High Falls contact probably lies within or at the base of the lower argillaceous dolostone unit. Studies of cross-laminations and ripple marks by Christianson (1969) indicate a marked net shift of sand toward the southwest (S75°W). Some years ago Susan Mocco, a student in the Dept. of Geological Sciences at S.U.N.Y. New Paltz, studied this section extensively to determine if there was indication of periodicity in the lithological variation within the main sandstone unit. The variation appears to be more random than periodic. Note the silicified stromatoporoid coenosteum in the upper massive unit, and flat shale pebbles in the bottom of the main sandstone unit.
Caution - As at STOP 2. please avoid falling into the mines as it will unnecessarily delay the trip!

STOP 4. Binnewater sandstone / High Falls shale
Binnewater sandstone unit in contact with High Falls Shale
Caution -The roadway is narrow and local drivers often speed along this stretch.
At this location the main sandstone unit is all that remains of the Binnewater at this latitude and it is in distinct contact with the High Falls Shale. The lower shale unit and the bottom dolostone unit are missing, probably indicating an onlap relation with the High Falls in an apparent northeast direction. The High Falls at this location is an uncharacteristic, poorly sorted, argillaceous, quartzose, quartz pebble-bearing material which was mistaken for a basal unit of the Binnewater sandstone by Waines and Sander (1968. p. 18).

Pass under Nytrallte conveyor.

STOP 5. Main sandstone unit of Binnewater
At this location the Binnewater Sandstone consists solely of the main sandstone unit which is completely exposed at the north end of the outcrop. The unit consists of an upper dark, somewhat silicified portion and a lower lighter colored portion. This subdivision occurs only locally. Cross-lamination is primarily confined to a very narrow zone. Dolomitic content in this section is uncharacteristically high. The Binnewater-Rosendale Dolostone contact is delineated by a discontinuous line of bleeding pyrite and can be closely observed at the north end of the outcrop. The Binnewater-Ordovician contact can best be seen near the base of the outcrop several tends of feet south of the main exposure of Binnewater. The contact is in angular unconformity with Ordovician shales, siltstones and greywackes. Quartz pebbles occur within the base of the Binnewater up to several inches above the contact. In several large blocks of Binnewater Sandstone which have fallen forward from the outcrop a cross-laminated, ripple-marked, mud-cracked bedding plane can be observed along with the Binnewater-Rosendale contact. Preliminary estimates of net sand transport from cross laminations indicate a general net shift to the south.

STOP 6: Rondout Creek Falls
Walk north to edge of Rondout Creek and observe falls from platform. Do not crowd! Upper contact of Binnewater Sandstone with Rosendale Dolostone occurs near base of falls and can be observed only with difficulty if at all. A complete exposure on the far side of the river is not accessible on this trip. Continue downhill (east) on paved road and observe exposure of Binnewater on right (south). This sequence lies somewhere in the middle and lower part of the Binnewater. Generally the Binnewater is not quite the same as in the Rosendale area. The sands especially in the lower part become somewhat vugular and tend to be more dolomitic.
Occasional traces of red coloration begin to appear. The lowermost five feet or so are somewhat transitional to more typical High Falls lithology. The lower part of the section is in some ways more akin to that in the Accord drill core which will be displayed at Vassar at the conclusion of this trip.

STOP 7. Rosendale Limestone
Here the Rosendale Limestone contains a highly arenaceous unit at the base which disconformably overlies a laminated, soft weathering, argillaceous dolomite with the fissility of shale. This has been referred to as the Accord Shale by Fisher (1959). Drill cuttings of the top six feet of this unit obtained in a nearby quarry were examined for insoluble residues through six inch intervals by Ruth Ellen Nielson, a student at S.U.N.Y. New Paltz several years ago. All residues proved less than half the samples by weight; generally between thirty and forty-five per cent. Harry Dembicki, another student, determined a general fifty-fifty ratio in the Ca/Mg ratios in the dissolved portions of the samples suggesting dolostone. According to drill core taken in a nearby boring, this argillaceous dolostone unit is about 14 feet thick. The disconformable contact with the overlying Rosendale Limestone can also be seen in the same core. There is a possibility that ostracods may be found in this outcrop. One was encountered in the drill core in about this interval. Possible relation of this dolostone to the Binnewater Sandstone at High Falls is indicated in figure 2.

On left is quarry
On left is quarry mainly excavated in Rosendale Limestone. Road skirts northwest side of quarry. Drill core mentioned at STOP 7 was taken on far side of quarry.

B4: STRATIGRAPHY AND STRUCTURE OF SILURIAN AND DEVONIAN ROCKS IN THE VICINITY OF KINGSTON, N.Y.
Kenneth Pedersen
Michael Sichko, Jr.
Manfred P. Wolff
On this trip the lower contact of the Rondout formation will be observed at two locations. In the southernmost exposure at Tillson Hill the Rondout lower contact is sharp to gradational with the Binnewater sandstone. The significance of this contact is that it is in paraconformity or conformable with the earlier Silurian rocks.
At stops two and three to the north of Kingston (Fig. 1) the lower contact of the Rondout formation lies in angular unconformity to the Ordovician Normanskill formation. At these two northern stops the Shawangunk conglomerate, High Falls
shale and Binnewater sandstone are all missing. There are three possible hypotheses which may explain this :
a. The northern area was being eroded while the southern area was submerged for deposition (a Silurian shoreline).
b. The northern area was undergoing deposition and later erosion. Thus, eroding the unconsolidated earlier Silurian sediments (a regressive sea).
c. In the later Devonian time, the entire area was thrust faulted and the angular unconformity is a thrust fault plane.
The authors favor explanation "a" since the missing formations are all thinning in a northeasterly direction although there is some evidence in support of each hypothesis
In the later Silurian the upper part of the Rondout formation was gradationally deposited with the Thacher limestone of Early Devonian. The Silurian-Devonian time division has therefore been placed within the upper Rondout formation (Rickard, 75). The Early Devonian was characterized by rather low energy environments in which a general carbonate and calcareous mud sequence was deposited.
The lower Devonian carbonates are exclusively marine, although the energy levels vary indicating fluctuations in sea level throughout the area. The lowermost Thacher limestone is variable from low to high energy levels perhaps tidal to subtidal while the Thacher is biostromal near the top.
From the overlying Ravena limestone through the Kalkberg limestone and New Scotland formation the energy levels fell off and the sea level was rising until the depth exceeded 200 feet at local wave base level. This sequence was followed by a recession of the sea during the deposition of the Becraft limestones. The environments deepened again during the deposition of Alsen limestone and the Port Ewen formation.
Fluctuations occurred perhaps during the deposition of the Glenerie formation and stabilized in a deep water environment during Esopus and Schoharie times (Waines, 67).
The Middle Devonian Period is initiated with the deposition of the cherty Onondaga Limestone which has been subdivided into various units (Oliver, 1956, 1962). Only the Edgecliff and Moorehouse members occur in this region. This culminates the lower Paleozoic periods of carbonate deposition; the remainder of the Paleozoic is now characterized by the various clastics derived from the uplifted New England provinces deformed during the Acadian orogeny.
The first major pulse of sediments (Hamilton Group) form a vertical and lateral progradation of marine, coastal, and alluvial deltaic environments that continue to fill the various embayments near the edge of the basin and spread westward across the state - the initial development of the classic Catskill delta or deltaic complex (Barrell, 1913, Chadwick, 1933, Wolff, 1965, Friedman and Johnson, 1966).
This trip will examine some of these sediment phases or "facies" as represented by the Marcellus Formation (Table 1). Each of these units can be traced northward by physical correlation because of the similarity between regional structure (the Hoogeberg escarpment) and depositional strike, and then westward by thickening rates (Rickard, 1964) and paleontological control (Cooper, 1933). The vertical section of rock units and inferred depositional environments seen here are quite similar to those seen southward toward Pennsylvania (Mazzullo, 1973) and northward toward Albany (Wolff, 1969).
The Onondaga Limestone is conformably overlain by the fissile, black, Bakoven Shale which transitionally grades into the Stony Hollow Siltstone. Both of these units are slightly calcareous. They are overlain by a thick sequence of interbedded dark gray shales, siltstones, and massive fine-grained sandstones (Mt. Marion Fm.), and these transitionally grade into the cross-bedded, relatively unfossiliferous, sandstones of the Ashokan Formation. This unit, of variable thickness, is also transitionally overlain by the sandstones and shales of the Plattekill Formation. The presence of red shales and mudstones in place of only olive-green knobby mudstones adjacent to and in conjunction with the cross-bedded sandstones, is used as the facies boundary between these units.
The entire vertical section represents the single initial deltaic progradational sequence followed by a series of at least four other major deltaic sequences (Wolff, 1965, 1969) within the Devonian "Catskill deltaic complex." Road stops (5A-B) will begin at the top of the section (Table 1) in the Plattekill Formation and end at the Bakoven Shale. Previous trips examining the stratigraphy of this area include: Dunn and Rickard (1961), and Wolff (1969).

B4: STRATIGRAPHY AND STRUCTURE OF SILURIAN AND DEVONIAN ROCKS IN THE VICINITY OF KINGSTON, N.Y.

STOP 1. Silurian System - Tillson Hill, N.Y.
This stop shows an exposure of the formations of Silurian age which are exposed in the Hudson Valley. The Shawangunk conglomerate, the High Falls shale and the Binnewater sandstone are all found below the Rondout formation. The contact between the Binnewater sandstone and the Rondout formation is conformable at this locality. Farther North, however, the Rondout is found in angular unconformity to the underlying Normanskill formation of Ordovician Age. Proceed north on route 32 toward Kingston, N.Y.

STOP 2. Subterranean Ord/Sil unconformity.
Subterranean exposure of the Ordovician-Silurian angular unconformity.
The steeply tilted Normanskill formation is exposed in angular unconformity with the Rondout formation. At this location the only remnants of the Rosendale and Whiteport members are the columns which support the roof in the mines (Fig. 3).

STOP 3. Subaerial exposure of unconformity
Again the Normanskill-Rondout angular unconformity. At this locality, major structural deformation due to the Taconic Orogeny are easily observed.

STOP 4. Thrust faulting
Thrust faulting within the Thacher member of the Manlius limestone:
The Thacher limestone shows major structural deformation from the Acadian Orogeny in the form of thrust faulting. The carbonaceous interbedded shales have been metamorphosed into phyllites and phyllites schists.

New Paltz Ashokan campus. Lunch Stop

STOP 5A: Plattekill Formation (Catskill Facies)
Stream channel environment.
Exposure consists of 14 feet (4.3 m.) of flat bedded and planar cross-bedded sandstones. These occur in a series of overlapping and truncated wedges averaging 1-3 feet (0.3-1 m.) in thickness (Figure 5). The individual dark subgraywackes are 1/2 to 2 inches (1-3 cm.) thick and form accretionary slopes of 2-5°, While the regional direction of flow is S80°W, the individual sets of crossbeds trend northeast-southwest. Rather than a major upward-fining alluvial channel, this section is interpreted as an area of shallow distributary or braided stream channels laterally filled through point bar accretion and vertically filled by channel aggradation.

STOP 5B: Plattekill Formation (Catskill Facies)
Floodplain environment.
Base of outcrop consists of 17 feet (5.2 m.) of knobby red-green mottled mudstone grading upward into 4-6 feet (1.3-2 m) of olive green mudstone. Section is disconformably overlain by a sequence of medium-gray, shallow-dipping planar cross-bedded sandstones. The regional paleoslope across the megarippled erosional surface trends S70°5. The zone of recent differential erosion about 8 feet (2.5 m) above the base represents a section of westward lateral compression producing minor folding, slickensides, and thrusting within the red mudstones - a minor decollement (Figure 6.) This section is about 200 feet (61.5 m.) above the base of the Plattekill Formation.

STOP 6: Skaneateles-Marcellus Formations
(includes the local Ashokan and upper Mt. Marion Formations)
Contains features characteristic of the Chemung-Hamilton facies (intertidal environment). Use parking lot of Micrometries, Inc. on the south side of the road.
A. Southside of Rt. 28 roadcut - Mottville and Ashokan Sandstones. Major feature is the 8 foot (2.6 m) laminated and cross-laminated, moderately sorted, planar crossbedded sandstones. These occur on a series of en-echelon "sand bars" here, over 130 feet (40 m.) wide and interbedded with dark shales and massive, fine-grained, bioturbated sandstones. These bars strike N70°W and have steep "foreshore" slopes (20°) trending northeast with more gentle (10-15°) "backshore" dips. Overlying the sandstones is a 5 foot (1.8 m.) succession of dark shales and fine-grained laminated sandstones with abundant plant fragments. This part of the section has been traced to Schoharie Valley (Mottville Sandstone) and is interpreted as a series of river mouth bars, intertidal or shallow subtidal sandbars, and sandflats (Wolff, 1969). These marginal sandstones are steeply truncated by a 40 foot (12.6 m.) section of thick, large-scale trough and planar cross-bedded sandstones with irregular lenses of olive mudstone (Figure 7). Individual beds are 2-4 inches (4-7 cm.) thick and dip at angles of 2-10° to the northwest. Worm burrows, shale chips, and plant fragments are common. This section represents the first major intertidal channel cutting across the sequence (Ashokan sandstone). The paucity of marine fossils may reflect the alien ecologic conditions that would be associated with the rapid lateral and vertical erosion and sedimentation in this environment. However, small crustaceans Estheria (a brachiopod) and Beryrichis (an ostracod) have been collected in several areas at this interval (Goldring, 1943, p. 268) supporting a brackish-water interpretation.
B. North side of Rt. 28 -upper Mt. Marion Formation. Suggested to be equivalent to Pecksport member of Marcellus Formation (Copper (in Goldring) 1943, p. 260, and Wolff, 1967, 1969). Outcrop consists of 9 feet (2.8 m.) of brown-black interbedded shales and siltstones capped by a 3 foot (1 m.) bed of dark, small scale, planar cross-bedded sandstone (equivalent to base of section on south side of road). Many of the shales exhibit an "oily" iridescent purple sheen. Structures include wave ripples, laminations, cross-laminations, lenticular bedding, flaser bedding, worm burrows, and tidal bedding -all features that can be associated with lagoons and tidal flats (Reineck, 1963, Klein, 1970). Fossils include Schizophoria, Pterinopecten, Paraspirifer, and Tropidoleptus, and are representative though not diagnostic for the uppermost Marcellus (Pecksport member). This area is interpreted as a region of wide sand flats containing barrier base and beaches, lagoons or tidal channels, and marshes or swamps that formed between deltaic layer during a period of general submergence. (Figure 8). After submergence (Pecksport interval -A) there is an interval of transgression, reworking, and nearshore deposition (Mottville interval -B), before the next major pulse of deltaic sedimentation (Ashokan interval -C)

STOP 7. Marcellus Formation
(Portage Marcellus Facies)
Stony Hollow and Bakoven members (distal slope and basin environment)
Base of section consists of 22 feet (6.6 m.) of thinly laminated black calcareous shales, commonly drag folded and faulted (underthrusts). The next 8 feet (2.3 m.) also contain black calcareous concretions (frequently slickensided), and compression fractures with quartz veins. The Bakoven is about 100 feet (30 m.) thick, but only the upper portion is exposed here. This unit grades into 8 feet (2.3 m.) of dark gray massive calcareous siltstones. The near vertical joints, trending N60°E are quite characteristic. Upon weathering the buff-colored surfaces exhibit the laminations or cross-laminations commonly associated with this unit. These may represent deposition by waning turbidity, or other marine currents. The siltstones contain some detrital carbonate and a few fossils, and become more massive through this 35 foot (11 m.) section. It is equivalent to the Cherry Valley (Agoniatite) Limestone in central New York and was first described by Cooper (in Goldring), 1943.

STOP 8: Marcellus Formation Portage Facies
Locally the lower Mt. Marion Formation or the sandy equivalent of the Chittenango member of east-central New York.
Road cut consists of 120 feet (37 m.) of dark gray arenaceous shale with some anomalous interbedded fine-grained sandstones through the lower 20 feet (6.2 m.) of the section. The overlying shales contain light gray concretions and include 5 "coquinite" fossil horizons. Of significance is the Meristella -coral zone in the central zone (now covered by the weathered shale) and horizons of brachiopods and pelecypods. Cooper (in Goldring) 1943, traced this horizon from the Berne Quadrangle (S.W. of Albany) into this area. The interval between the Stony Hollow member and the Otsego Shale was designated as the "Berne member" (Cooper, op. cit., p. 249) but it was restricted because of the few known locations. The extension of this member to the Kingston area enables it to be also correlated as the sandy equivalent of the Chittenango Shale (Cooper, op. cit.), and establishes the contact between this shale and the Otsego Shale in this region (Wolff, 1967, 1969). The pull apart and transposition structures at the base of this section (Figure 9) are described in the structure section of this article.

STOP 9. Gentle folding in the lower Devonian Rocks
Here the gentle anticlines and synclines expose the lower Devonian section almost in its entirety. We are proceeding downward in the column so the rocks encountered are in the following sequence: Schoharie, Esopus, Glenerie, Port Ewen, Alsen, Becraft, New Scotland, Kalkberg, Ravena and Thacher (Waines, 1967).

B5: PLEISTOCENE HISTORY OF THE MILLBROOK, NEW YORK REGION
David J. Murray
LaGrange Junior High School
Pleasant Valley, N. Y.
Location, Physiography, Relief and Drainage
The Millbrook, New York quadrangle is centrally located in Dutchess County, New York, mid-way between the Hudson River and the State of Connecticut (to the east) and New York City and Albany (to the north). The topography of the southern half of the quadrangle is generally hilly with areas of low relief be tween the hills. These areas appear to be lake plains of ice-marginal lakes formed during the retreat of the continental ice sheet from the Mid-Hudson Valley. Subsequent erosion of the lacustrine deposits has formed flood plains and terraces. The lowest elevation, about three hundred feet above sea level, occurs on the western border of the map area in the flood plain of the east branch of Wappingers Creek. A series of progressively higher rock ridges trending northeast-southwest traverse the quadrangle. The highest elevation, Tower Hill, rises to 1323 feet. The valleys between these ridges are probably pre-glacial in origin but at present are partially filled with glacial deposits. The larger valleys have terraces along the sides.
The area is drained by tributaries of three major creeks. Tributaries of Wappingers Creek on the west and Fishkill Creek on the south, flow into the parent streams and then into the Hudson River. The extreme eastern part of the area is drained by unnamed tributaries of the Ten Mile River, which flows into the Housatonic River in Connecticut. These tributaries originate in elevated bogs and small kettle ponds and lakes.

B5: PLEISTOCENE HISTORY OF THE MILLBROOK, NEW YORK REGION

Cross Wappinger's Creek.
This creek provides drainage from field trip area.

Pass Dutchess County Farm and Home Center.
This site is on the east side of former Glacial Lake Washington.

Pass Bennett College

STOP 1. Town of Washington Disposal Area.
Sanitary Landfill. This is the highest level of the field trip area. Look for massive kettle holes and distorted bedding, due to slumping as buried ice blocks melted. Top elevation 900 feet.

STOP 2. Deltaic deposit
Deltaic deposit consisting of foreset and topset beds dipping west indicating source of sediments from east into Glacial Lake Mabbettsville.

STOP 3. Observe lake plain and lake terrace
Pull into Dutchess Day School Driveway on right. Observe lake plain and lake terrace indicating Glacial Lake Mabbettsville.

Kame and kettle topography
Note kame and kettle topography on right in field next to swimming pool.

STOP 4. Large gravel pit.
The sand and gravel from this pit is used "as is" as a high grade bank run gravel. It is quite well sorted and fairly free of silt and clay sized particles. Foreset and topset beds visible in this massive deltaic deposit in Glacial Lake Washington.
2013: Good Google Earth image from 1994 shows excavation.

Lunch Stop. Cary Arboretum
The Cary Arboretum of the New York Botanical Garden is a 2000 acre tract of land devoted to botanical research, applied environmental science, and education about plants. It was established in 1971 with a grant of land and funds from the Mary Flagler Cary Charitable Trust on an estate owned by the late Mrs. Cary.

STOP 5. Level ground underlaid with deep gravel
Level ground underlaid with deep gravel; bedding almost horizontal. Look for fairly well sorted gravels and stagnant ice features.

STOP 6. Level field is a delta surface
Level field is a delta surface at 440 feet elevation. Soil on left side of road is dramatically different from soil on right side of road.

Bear right across Glacial Lake Washington plain.

STOP 7. Bridge across Wappinger's Creek.
Inferred history of Glacial Lake Washington will be discussed.

STOP 8. Gravel pit
Gravel pit is an exposure of poorly sorted outwash overlaid with ground moraine on western margin of Glacial Lake Washington.

Deltaic Deposit
On right side of Route 82 at this point a deltaic deposit was removed for road building material. Bones thought to be those of Indians were found here in 1973 but have not yet been authenticated.

STOP 9. Large gravel pit
This large gravel pit operated by the Route 82 Sand and Gravel Company has a variety of features that will be discussed here.

B6: STRATIGRAPHIC AND STRUCTURAL GEOLOGY IN WESTERN DUTCHESS COUNTY, NEW YORK
Donald W. Fisher State Paleontologist, Geological Survey,
New York State Museum and Science Service, Albany, New York 12234*
A. Scott Warthin Jr.
Professor Emeritus, Geology, Vassar College
Poughkeepsie, New York 12601
*Published by permission of the Director, New York State Science Service. Journal Series No. 217.
PROLOG
Sedimentary rocks with deceptively similar but subtly different physical characteristics and yielding rare and hard-to -identify fossils demand exceedingly careful scrutiny. When, however, a further measure of obscurity arises because such rocks are overprinted by poly-deformational complex folds, faults, cleavage, and metamorphism, the demands made upon the investigating geologists are, indeed, taxing. This is the situation confronting those who attempt to unravel the geological maze of Dutchess County and eastern New York.
On this trip, our intention is to expose you to some of the knotty problems that beset us and permit you to examine some of the typical rock units and typical structures of the region. Owing to time limitations, we shall confine our visitations to western Dutchess County from Poughkeepsie northward -- and not all the rock units nor all types of structures will be examined. If we make you aware of the fascination and frustration of Taconic geology, then we have succeeded in our mission.
ACKNOWLEDGEMENTS
John B. Skiba, Senior Cartographer with the New York State Geological Survey, skillfully prepared the charts and maps which accompany this article and make for better understanding of the perplexing geologic relationships. The pictures taken from the U-2 aircraft and the ERTS satellite image were furnished by Yngvar W. Isachsen of the New York State Geological Survey.

B6: STRATIGRAPHIC AND STRUCTURAL GEOLOGY IN WESTERN DUTCHESS COUNTY, NEW YORK

Middle Ordovician Snake Hill Shale on left.
Proceeding in lower Ordovician-Cambrian carbonate valley. Megabreccia (?) of carbonate blocks deposited on Snake Hill mud.

Road cut in Rochdale Dolostone.

Village of Pleasant Valley, crossing Wappinger Creek.

Lower Cambrian Nassau pelites
Have entered the Van Buren gravity slide.

Lower Ordovician Stuyvesant Falls green shale
Lower Ordovician Stuyvesant Falls green shale, and thin quartzites on NW(left).

STOP 1. Camb-Lower Ord Germantown Fm
Intersection of Drake-Rossway Rds. &T.S.P. Exposures of Cambrian-Lower Ordovician Germantown Formation along both lanes of T.S.P., north of intersection. We shall examine only the western cut on the southbound lane. Here, almost vertical dipping platy, silty shale with very thin-bedded limestones and carbonate-clast carbonates are superbly exposed. Tight drag folding indicates that we are on the eastern limb of a larger synclinorium. Note the quartzose limestone beds. These and the carbonate-clast conglomerates have large and well-rounded frosted quartz grains; the clasts consist of fine-textured limestones and differing types of dolostones and black phosphate pebbles. These conglomerates are thought to be lag-turbidites on an ancient continental slope.

Lower Cambrian Nassau shales and argillites.

Valley floored with outwash gravels.

Kame terrace on E side of valley.

Everett Schist in hill on left.
Lower Cambrian or Late Proterozoic Everett Schist in hill on left. Everett is thrust-faulted, westwardly, onto Middle Ordovician Snake Hill (= Walloomsac) Shale.

STOP 2. Intersection of Todd Hill Rd. and T.S.P.
Here we have a geological enigma -- an exposure of Proterozoic gneiss in an area far removed from larger masses of Proterozoic gneiss. This orange feldspar-rich granite gneiss does not have a normal shelf stratigraphy (Poughquag Quartzite, Wappinger carbonates) associated with it as does the Cronomer Hill section at Newburgh or the Stissing Mt. section near Pine Plains. Todd Hill and a smaller hill to the SW are flanked on the east by Everett Schist and Mount Merino(?) Shale. respectively. These two gneiss hills are bounded on the W by a major NE-trending fault. The field relations deny the views that these gneiss hills were islands around which Cambrian and Ordovician sediments accumulated or that the gneisses were up-punched due to doming or normal block faulting (horst). The gneiss owes it position as a result of far-travelled movement--either as a sliver along a low thrust fault or as an erosional outlier of a once larger overthrust mass of gneiss, such as the Hudson Highlands. We prefer the sliver supposition.
2013: Crossing the Taconic State Parkway is no longer considered a good idea, so we will go back, and around, to get to the other side.

STOP 3. Normanskill Group
Noxon Rd. E of Sprout Creek (D.C. 21) rock cut. Here, we have the Mt. Merino Shale on the west and the Indian River Shale on the east -- the middle and lower divisions of the Normanskill Group, respectively. The Mt. Merino is a gray to black shale or mudstone locally with gray to black chert; the Indian River is a pale green to red to maroon shale or mudstone with light green to red chert; within the Indian River here is an unfossiliferous dove-tan-gray, fine-textured limestone. Three and possibly four episodes of folding are displayed here. One set has horizontal axial planes, another has westward dipping axial planes with N-plunging folds, and a third are small drag folds which appear to be refolded. In addition, the penetrative cleavage is folded. The interpretation is that this outcrop exposes a portion of a lower limb of a westwardly overturned fold (nappe). Small discrete bodies of graywacke, more convex upward and to the east, are probably turbidites; they too, are upside down. No fossils have been found at this exposure but elsewhere, where less deformed, the Indian River and Mt. Merino yield graptolites characteristic of the Nemagraptus gracilis zone of the Early Medial Ordovician.

Spackenkill Rd. (D.C. 76). Slow, but no full stop.
On S (left) side of Spackenkill Rd. is a block of Wappinger (Briarcliff) carbonate in the Snake Hill Shale. This is regarded to be part of an extensive NE-trending megabreccia extending from the Cronomer Hill area at Newburgh, generally following Wappinger Creek and reaching Stissing Mountain near Pine Plains. Although the precise sequence of deformational events is uncertain, this megabreccia is believed to be an early melange deposit in the Snake Hill mud, created by the ripping-up of underlying shelf carbonates as the pelitic Van Buren gravity slide moved westward. This exposure is but one of many carbonate blocks illustrating various attitudes and differing Wappinger units.

STOP 4. West side of Cedar Valley Rd..
(NO ROCK BREAKING OR SAMPLING, PLEASE.)
Here, we have opportunity to see the significant Middle-Lower Ordovician contact, -- a profound erosional unconformity on a regional scale. At this exposure, the Middle Ordovician (Mohawkian) Balmville Limestone rests on the Lower Ordovician (Canadian) Rochdale Limestone. In some parts of the Hudson Valley, the Balmville rests on older rocks -- as old as Medial Proterozoic gneisses.
The Balmville consists of medium-dark gray, coarse-fine textured limestone, fossil fragmental, and, locally, with a pebble conglomerate composed of clasts of finer textured, light gray weathering limestone of buff-weathering dolostone. Some "clasts" are colonies of the alga Solenopora. The Balmville is relatively fossiliferous but whole specimens are difficult to obtain. Brachiopods, crinoids, and bryozoans are the principal taxa; algae, conodonts, gastropods, ostracodes, and trilobites are secondary taxa. The subjacent Rochdale Formation is fine-textured, bluish-gray to black limestone with interbedded paler bluish-gray, buff weathering dolostones. In some beds. the proportion of calcite to dolomite varies considerably; this produces a fretwork appearance to the weathered surface. The Rochdale is Medial Canadian (Demingian) age as evidenced by the diagnostic discoidal gastropod, Leaanospira, the trilo Hystricurus conicus, and the cephalopods Bassleroceras, Dwightoceras, and Vassaroceras. Stromatolites are also occasionally seen. The Rochdale seems to have been deposited in a low-energy, distal intertidal environment whereas the Balmville is a product of extremely high-energy conditions on an ancient beach.
The dip varies from 55°E at the northern end of the exposure to near vertically at the southern end. The observed rocks are on the eastern edge of an elongated carbonate block with Middle Ordovician Snake Hill Shale occupying the lowland to the east and the adjacent lowland to the west of the NE-trending carbonate ridge.

STOP 5. East side of Cedar Ave. (D.C. 74)
This long exposure is in the Briarcliff Dolostone division of the Wappinger Group. Note the variation in textures and colors in the dolostones. Small faults with only a few centimeters displacement and microbreccias are common. A more prominent normal fault across from the parking area trends N70°E and dips almost 90°. A short distance to the east, the Briarcliff abruptly ends in a cliff; Snake Hill Shale occupies the bounding lowland. This is the eastern extremity of the relatively large block of carbonate that is exposed in the large Clinton Point Quarry on the Hudson River. Here, earthquakes have been documented from 1937 to the present. It is speculative whether this Cedar Ave.-Clinton Point block is (1) an exceedingly large block in a megabreccia, (2) an up-punched block bounded by normal faults, (3) the leading edge of a thrust block, or (4) a megabreccia block trimmed by subsequent block faulting. Because of its proximity to known, but smaller, megabreccia blocks, we favor views (1) or (4).

Note gentle dips in Briarcliff Dolostone in every exposure.

Briarcliff Dolostone
Note outcrop of Briarcliff Dolostone just north of Robert Hall Store. Dips are abnormally steep and may record bevelled isoclinal folds or indicate proximity to a fault. This is the western margin of the Cedar Ave.-Clinton Point carbonate block.

STOP 6. KAAL PARK (LUNCH)
NO HAMMERING, THIS IS A CITY PARK.
This is an exquisite exposure of a tectono-sedimentary unit known as chaos, melange, olistostrome, or wildflysch. Fisher (1976, in press) has named this unit the Poughkeepsie Melange. It consists of various sized, angular to rounded clasts of rock (with varying attitudes) in an unbedded or poorly bedded argillaceous matrix. Here, the blocks are almost exclusively Austin Glen Graywacke; elsewhere, there are varying amounts of quartzite, sandstone, shale, and carbonate. This type of sedimentary-tectonic unit is believed to result when westwardly moving rock masses broke up at their leading edge, spalled off, and tumbled downslope into a deepening basin which was receiving mud. Evidences of soft-sediment deformation are widespread. This deposit accumulated during the Vermontian Phase of the Taconic Orogeny (mid-Mohawkian time) when the Livingston and Van Buren Gravity Slides were emplaced into the Magog (Snake Hill-Martinsburg) Trough. Rocks of the Livingston Slide are superbly exposed at the western end of the Mid-Hudson Bridge.

Numerous exposures of Poughkeepsie Melange.

Culinary Institute of America on W (left).

STOP 7. Exposures on both sides of St. Andrews Rd.
Here, the uppermost member of the Middle Ordovician Austin Glen Graywacke is deformed into broad, low amplitude folds. The somewhat cyclical shale-graywacke succession is cleaved and the cleavage is slightly bent, denoting that here we are at the western limit of a folding episode which deformed the earlier regional fracture cleavage. This stop, however, is more instructive for the wealth of sedimentary features that are to be observed: load casts, cross-lamination, cross-bedding, graded bedding, intra-bed clasts, climbing ripple marks, etc. Note also, the micro-folding of the thinnest seams. The abrupt change from arenite sedimentation (graywacke) to pelite sedimentation (argillite, shale) is striking. Many of the graywackes, especially the thicker ones, are turbidites as evidenced by the variety of load casts and trapped shale or pelite clasts.
The Austin Glen Formation is thought to have been deposited on an ancient continental slope where the sediments on the sea floor were unstable. This type of substratum was inhospitable to benthonic animals. A few pelagic forms (graptolites, radiolarians) have been recorded from the Austin Glen elsewhere in Dutchess County. The lower member of the Austin Glen belongs to the Nemagraptus gracilis zone and the upper member belongs to the Diptograptus multidene zone. Because of the absence of a shelly, benthonic fauna from all divisions of the Normanskill Group, its correlation with the shelf carbonates remains equivocal. Outcrop is in the Livingston Gravity Slide.

Austin Glen Graywacke
Exposures of very massive Austin Glen Graywacke in Livingston Gravity Slide. Continues for next 0.9 miles.

Outcrops of melange near intersection.

Germantown conglomerates, limestone, and shale
Germantown conglomerates, limestone, and shale on N (left) side. Have just entered Van Buren Gravity Slide.

Entering Gallatin Thrust Slice
Elizaville argillite and quartzite in numerous exposures on both sides.

STOP 8. Elizaville Argillite and Quartzite
Early Cambrian or Late Proterozoic Elizaville Argillite and Quartzite on Slate Quarry Rd.
The Elizaville consists of hard, compact greenish-gray slate and argillite (weathering tan to orange) and interbedded greenish-gray quartzite. Elsewhere, some of the quartzites attain 10 meters thickness. Here, the thinner quartzites are traversed by cross-fractures filled with milky quartz and iron carbonate (siderite). NO HAMMERING OR COLLECTING SIDERITE!!! On the west end of the exposure, the strata form a low fold with cleavage dipping 50-60° E. Further east, the bedding and cleavage are parallel (dipping 60° E). Where this coincidence exists, the chances for good quality commercial slate are better; abandoned slate quarries may be found on both N and S sides of the road in the woods. In general, in the Gallatin Slice, cleavage is predominant over bedding. And, cleavage is virtually undeformed.
No fossils have been discovered in the Elizaville Formation. It is presumed to be equivalent to part of the Nassau Formation of the Van Buren Slide.

Mt. Merino black shale on N (left) side.
Exiting from Gallatin Thrust Slice into Livingston Gravity Slide.

STOP 9. MILAN WINDOW: WAPPINGER carbonate
MILAN WINDOW: WAPPINGER (HALCYON LAKE?) carbonate on N side of D.C. 19 near intersection with D.C. 18.
This is a NNE-trending valley floored by Wappinger carbonates, Balmville Limestone, and Snake Hill Shale. Rimming this sequence of shelf rocks are slope and basin Normanskill graywackes and pelites of the allochthonous Livingston Slide. The window of parautochthonous shelf rocks was produced by differential erosion of part of the covering Livingston Slide and additional covering Gallatin slice; the Van Buren Slide was presumably eroded prior to the emplacement of the Gallatin Slice. Subsequent normal faulting may have accelerated erosion and the creation of the Milan Window. This stacking of gravity slides and thrust slices is seen to no better advantage than in this region of the Rock City Quadrangle. Mapping of the divisions of the Wappinger Group has disclosed here, and in other lengthy carbonate terranes, the existence of a NW-SE trending fault set (strike-slip faults) which, seemingly predate the gravity slides. These faults may have been the product of stresses in effect during expansion of the Proto-Atlantic Ocean. The slides and slices were formed during contraction of the Proto-Atlantic Ocean.
Field relations at the Milan Window demonstrate that the parautochthonous carbonates (megabreccia?) were emplaced prior to the transport of the slides and slices -- an important criterion in documenting the regional geologic history.

E edge of Milan Window.
Several exposures of Mt. Merino black shale on both sides of road almost to T.S.P. (black shale on S side of road).

Melange exposures on T.S.P. near intersection.

Everett Schist on both sides of road.

Everett Schist on E (left).

Crossing into Van Buren Slide
Crossing into Van Buren Slide near intersection with Knight Rd. Indian River green and red shales and cherts.

Germantown fm to S, Stuyvesant Falls fm to NW
Germantown gray-black shale in borrow pit on S side of intersection; Stuyvesant Falls Formation in cliff NW of intersection.

Indian River
Indian River green and red mottled slates near Tinkertown Rd.

Wappinger carbonate valley
Re-enter Wappinger carbonate valley at Pleasant Valley.

Rochdale limestone and dolostone on both sides.

STOP 10. Rock cut and fault along Penn Central R.R.
At the western end of the railroad cut is an apparent high-angle reverse fault with Late Cambrian Briarcliff Dolostone on the east and the Middle Ordovician Snake Hill Shale on the west. Note the gouge (mylonitized) zone along the contact. The question here is whether this is a bonafide high-angle reverse fault, east being the overriding block, or rather a carbonate block which has gravity slid into the Snake Hill mud; the illusion of a high-angle fault may have been created subsequent to sliding by rotation of the strata during an Acadian (Middle Devonian) folding episode.
The fault plane dips 75-80° E and there is no apparent drag here or anywhere else along the western margin of this carbonate block. At New Hamburg, along the railroad on the Hudson River, the fault plane dips 35-40° E. The absence of drag and variable dips of the "fault plane" tend to argue for a "block-in-shale" situation.

B7: PROGRESSIVE METAMORPHISM IN DUTCHESS COUNTY, NEW YORK
A. E. Bence
SUNY-Stony Brook
J. M. McLelland
Colgate University
The purpose of this trip is to examine the development of regional progressive metamorphism within southeastern Dutchess County, N.Y. All stops, except the first, lie within the Clove 15' quadrangle (Fig. 1). Localities to be visited have been chosen in order to show a variety of mineral assemblages beginning with rocks at chlorite grade and proceeding eastward through the first sillimanite isograd. The majority of lithologies to be examined are pelitic with interbedded cherts and quartzo-feldspathic rocks. One stop will be made within units of the carbonate shelf sequence where calc-silicates may be seen. The implications of recent geochronological studies will be discussed relative to the geologic history of the area.

B7: PROGRESSIVE METAMORPHISM IN DUTCHESS COUNTY, NEW YORK

Mt. Merino member of Normanskill Fm.
Between here and Stop 1 the Mt. Merino member of the Normanskill Fm. is exposed at a number of localities in the surrounding fields.

STOP 1. Chlorite Grade - Roadcuts
The purpose of this stop is to display typical pelitic lithologies at low metamorphic grade (i.e. chlorite zone). Similar lithologies, though not necessarily identical stratigraphy, constitute the metapelites to be visited at later stops.
The east end of the cuts consists of typical red and green slates and phyllites of the Indian River member of the Normanskill Fm. At the west end of the cut black slates, phyllites, and greywackes of the Mt. Merino member are exposed. The contact between these two units occurs just at the western end of the red Indian River exposures. Some faulting appears to have occurred along the contact and a later northwestward dipping reverse fault, with associated fracture cleavage, further complicates relationships. These roadcuts are part of a small erosional remnant of a larger allochthon whose principal exposure lies just north of Freedom Plains, N.Y. and is well exposed in the vicinity of James Baird State Park (Fig. 1).
Mineralogically the red phyllites and slates consist of hematite-chlorite-muscovite-plagioclase-quartz. The green lithologies consist of muscovite-chlorite-plagioclase-quartz. These differences imply a variation in oxidation state whose origin is not well understood. Gradations in color occur along strike of the beds and suggest that the variations may be secondary in origin.
The eastern portion of the roadcut consists of several relatively large (λ = 50-60'), upright folds on which are developed a multitude of parasitic chevron folds. Fold axes trend N30-50E and plunge NE at between 10° and 60° with most of the steeper plunges on the north side of the road. The style of folding is of the rounded, chevron type with minor folds reflecting the symmetry of the larger structures. Late flattening appears to have occurred. Associated with these folds is an axial planar crenulation cleavage that strikes N30-50E and dips steeply to the northwest. Close inspection shows that the cleavage intersects an earlier foliation that has been folded by the upright folds. The earlier foliation is usually subparallel to bedding but large intersection angles have been found.
Excellent weathered exposures, and a good overall perspective of the folds in the roadcut, can be found by climbing to the top of the cut.
At the western end of the cut the Mt. Merino slates and phyllites have undergone extensive kink folding with associated axial plane crenulation cleavage which strikes N40-50E and dips steeply to the west. Presumably these kinks are of the same generation as the chevron folds in the Indian River. Greywackes within the Mt. Merino have deformed by buckling rather by kinking. Sedimentary structures can be seen within the greywackes and suggest that the section is not overturned.

Roadcut in green phyllites of Everett Fm.
Roadcut in green phyllites of Everett Fm. (presumed allochthonous) on south side of road. This outcrop exhibits minor structure evidence for at least four phases of deformation. Kink folding and crenulation cleavage are abundantly developed.

Quartz-breccia fault zone.

STOP 2. Biotite Grade - Black Walloomsac slates.
The slates are highly graphitic and often contain large amounts of pyrite. A strong N20W, 60E cleavage pervades the rocks and is related to N20W minor folds in the outcrop. These folds rotate an earlier foliation. Mineral phases present in the rock are: biotite-chlorite-muscovite and plagioclase-quartz-ilmenite. The principle reason for stopping at this outcrop is that biotite is developed macroscopically and is easily visible with a hand lens. Here we are very close to the biotite isograd. Note that the biotite flakes grow across the planes of foliation. Be careful to distinguish flakes of biotite from ilmenite grains.

Black, graphitic, sulfidic Walloomsac slates.
Large roadcuts in black, graphitic, sulfidic Walloomsac slates. Vein quartz is abundant in the outcrop. Proceeding down the hill, we enter the Clove Valley which is underlain by Wappinger carbonates of the shelf sequence.

Cuts on south side
Going up the hill note the cuts on the south side of the road.

STOP 3. Garnet Grade
Small parking area on south side of road.
(a) Walk back down hill to examine cuts passed as we drove uphill. These consist of black biotite rich schists and cleaved metagreywackes. The observer is asked to compare these lithologies with the Mt. Merino seen at Stop 1. The principal foliation is N60E and dips 45°S.
In coming eastward from Stop 2 we have passed over the garnet isograd. At this locality garnet is sparsely developed in the more westerly (downhill) outcrops of black, graphitic biotite schists. The mineral phases in these rocks consist of garnet-chlorite-biotite-muscovite-feldspar-quartz (Fig. 4a). Proceeding uphill, the amount of graphite decreases while quartz increases, and the rocks begin to resemble greywackes. Within these units garnet is principally developed in thin beds which probably represent pelitic members in a turbidite sequence.
It has not been determined whether these rocks are allochthonous or autochonthonous. They are shown on the New York State Geological Map (1973) as Austen Glen greywackes. This designation, or an assignment to the Mt. Merino, would strongly imply that they are allochthonous. Approximately 1/4 mile south of here the metapelites are found overlying either Poughquag quartzites or the lowermost, quartzite rich, portion of the Stissing. If the rocks are not allochthonous, then the Middle Ordovician unconformity bevelled to the deepest portions of the shelf here, while 1.5 miles to the west the Balmville and Walloomsac rest on the Copake Limestone which occurs at the top of the Wappinger Group. This is by no means an impossible situation, but serves to emphasize the nature of the unresolved structural problems in the area.
(b) Return to parking area and walk north along the old dirt road to the north of the highway. After approximately 200' climb up to the exposures on the east side of the road. These small ledges show an exceptional development of chloritoid. Black chloritoid grains of up to 1/8" in length can be seen growing in seemingly random orientation. Microscopically the chloritoids are clearly younger than the principal foliations but are deformed by kinking and crenulation.
The mineral assemblage in these rocks consists of garnet-muscovite-chlorite-chloritoid-feldspar-quartz. As shown in Fig. 5a, this assemblage is the result of a more aluminous bulk composition than in the rocks at 3a. Here biotite is absent and is separated from chloritoid in an AKFM projection by the garnet-chlorite tieline (Fig. 5a).
At least two major foliations are present in the outcrop. An early N30E, 40S foliations appears to be related to small, attenuated isoclinal folds defined by thin quartz stringers. This foliation is generally parallel to compositional banding. The dominant foliation in the rock appears to be later and trends N80E, 25S. This foliation is axial planar to a sharp disharmonic fold exposed just above the ledge which best displays the chloritoid grains. Note that this fold folds an earlier foliation.
(c) Return to the paved highway and walk east up the hill examining the interlayered schists and quartzose rocks. Chloritoid is still present in some of these units but grain outlines are not as sharp as at 3b. This may be the result of the onset of a chloritoid consuming reaction. Biotite and chloritoid are still mutually exclusive and remain separated by the tie line garnet-chlorite. Although chloritoid is still present in some layers, most of the schists consist of garnet-chlorite-biotite-muscovite-feldspar-quartz. These lithologies are similar to the rocks at 3a, and chloritoid is unable to form because the bulk compositions are not sufficiently rich in aluminum (Fig. 5a). This serves to emphasize the control of rock chemistry on the development of chloritoid in the area.

STOP 4. Staurolite Grade
Low, rounded outcrop on the north side of the road.
These rocks are approximately along strike (N20E, 30E) with the chloritoid bearing schists at STOP 3b. Here we are at somewhat higher grade and staurolite is developed in thin section. The overall mineral assemblage in these rocks is (Fig. 5b). The presence of five ferromagnesian phases is clearly in violation of the phase rule and this assemblage cannot be in equilibrium. This locality marks the lowest grade at which staurolite is found and the highest grade at which chloritoid is stable. Note the coexistence of biotite and chloritoid both of which are visible in hand specimen. Clearly the tie-line chlorite-garnet is in the process of being broken by biotite-chloritoid. Simultaneously chloritoid is participating in a staurolite forming reaction.

Poughquag Quartzite on the south of Rt. 55.

Enter Edward R. Murrow Park for lunch.
The exposures in the park are Balmville limestones and Walloomsac schists.

STOP 5. Kyanite Grade up hill by power line
Park at dead end and walk up the dirt road, past a house, and continue along the footpath. The valley here is underlain by Balmville Limestone. After approximately 1/4 mile the path crosses beneath a power line. Turn east up the hill to exposures of staurolite-garnet-biotite-muscovite-quartz-feldspar schists (Fig. 5c). These rocks are typical of staurolite rich schists in the region. Good penetration twins of staurolite can be found. Kyanite appears to be absent at this locality, and this is probably due to differences in bulk rock composition (Fig. 5c). The outcrop here contains several large, recumbent isoclinal folds. One of these is dominant and its axial region is exposed near the top of the outcrop. The axial plane strikes N60E and dips 20° S while the axis trends N30W and plunges 10° N. however, the exposure may be out of place. An earlier foliation, defined by micas, has been folded by this structure.

Hudson Highlands.
Turn east and head uphill through Precambrian gneisses of the Hudson Highlands.

Precambrian/Paleozoic contact
Contact between the Precambrian and black, rusty Paleozoic schists (Walloomsac?). Balk (1936) mapped this contact as a reverse fault. Ratcliffe (pers. comm.) has suggested that the absence of the carbonate section may be due to the lower Middle Ordovician unconformity. Minor structures are consistent with Balk's interpretation.

STOP 6. Kyanite Grade - long roadcuts
The rocks in these long roadcuts have been mapped as Walloomsac schists (N.Y. State Geological Map, 1973). Whether they are, or not, is open to question. Regardless of stratigraphic uncertainty, the lithologies are dominantly pelitic with biotite rich schists predominating. Quartzose and granular quartzofeldspathic layers and lenses are interlayered with the schists and serve to define early isoclinal folds. The dominant cleavage trends N30-40E and dips approximate1y 50°S. This cleavage is axial planar to tight northeast trending folds which fold the earlier isoclinal folds whose general trend is also northeast. An earlier foliation is associated with these isoclines. In places the second generation folds have been flattened into isoclines. Minor folds associated with these give opposing senses of rotation as the roadcuts are traversed along their length and suggest that the entire roadcut has been telescoped by the second generation folds. A third of open N-S folds is present and associated with kinking and crenulation cleavage in the rock.
Mineralogically the schists generally contain biotite-garnet-kyanite-muscovite-feldspar-quartz. The kyanite appears as 1/8"-3/4" blue blades growing without orientation within the schists, and is particularly concentrated within more pelitic layers, many of which have thickened on the noses of folds. This gives rise to pod like areas that are extremely rich in kyanite. These can be examined to best advantage on the top of the roadcut where weathering has made the kyanites most visible. The metamorphic grade observed here is the same as at Stop 5 but staurolite is rarely observed in these rocks. This may be attributed to bulk compositional differences between the two localities (Fig. 5c). The rocks here are more magnesian than at STOP 5 and staurolite is generally excluded from the phase assemblage.
In addition to kyanite rich layers certain quartzose bands are extremely rich in garnet. Hornblende bearing pods are also present and represent more calcic bulk compositions in the original sediment. Biotite from a biotite-kyanite assemblage here gives an 40Ar/ 39Ar plateau age of 414 million years.

Roadcuts in the Walloomsac black schists.
A sharp anticline brings the Balmville limestone to the surface near the east end of the cut. This outcrop is situated near the hinge of the Harlem Valley Syncline.

Roadcuts in the Balmville Limestone.
Here the Balmville is directly overlain by Walloomsac black schists.

Walloomsac calc-silicates and Balmville Limestone.
The Harlem Valley can be seen directly ahead. We are now proceeding into the overturned, eastward dipping limb of the Harlem Valley Syncline.

Upper portion of the Wappinger Group
Calcitic marbles of the upper portion of the Wappinger Group are exposed to the south of the highway.

STOP 7. Very large roadcuts in the Briarcliff Dolostone.
This stop is the same STOP 7 in McLelland and Fisher (this volume), and the structure of the cut is discussed in that article. Petrologically this stop is of interest because it affords the opportunity to examine the development of calc-silicates at grades approaching the first--sillimanite isograd. Throughout the roadcut diopside, tremolite, and phlogopite are abundantly developed in the appropriate lithologies and are best seen on the weathered surface at the top of the roadcut. The most noteworthy example of calc-silicate development occurs close to the top of the roadcut near its eastern terminus. Here a two foot wide layer consists almost entirely of extremely coarse tablets, blades, and rosettes of white tremolite. The layer can be followed for well over 50 feet. In adjacent layers diopside tablets appear to be the only calc-silicates developed. Presumably this represents a very steep gradient in PH2O and a local system effectively closed with respect to the water migration across layers.

Briarcliff Dolostone
Low outcrop of Briarcliff Dolostone on the north side of Rt. 55. This outcrop contains outstanding examples of perfectly formed diopside tablets.

STOP 8. Sillimanite Grade
Roadcuts in coarse, muscovite rich schists.
Large garnets are developed. Sillimanite is present in this outcrop but has not been recognized in hand specimen. Tourmaline bearing pegmatites occur and suggest the onset of anatexis (Table 2).
Displayed within the roadcut are numerous examples of disharmonic folding in which the more competent quartzo-feldspathic units have broken and rotated. Early isoclinal folds may be seen. Many of these have attenuated limbs. Rootless isoclinal folds occur.

B8: ALLUVIAL AND TIDAL FACIES OF THE CATSKILL DELTAIC SYSTEM
Kenneth G. Johnson
Skidmore College
Within the uppermost Middle Devonian and lowermost Upper Devonian rocks of eastern New York State there occurs a remarkably complete spectrum of ancient sedimentary facies (Johnson and Friedman, 1969; Johnson, 1970, 1972, 1976). These beds, which evolved during a transgressive pulse in the building of the great Catskill deltaic system, are part of a 3000 meter sequence that constitutes the standard for the Devonian System of North America (Figs. 1 and 2). They are exposed at the northeastern end of the Allegheny Synclinorium, are essentially undisturbed and, for the most part, very fossiliferous. Laterally transitional between those beds that are clearly of marine origin and those that are clearly non-marine are sandstones and shales that have sedimentary structures, lithology, geometric relationships with adjacent units and biogenic structures that indicate that they evolved in tidal environments generally similar to those of the modern Wadden Sea.
The purpose of this trip is to outline evidence for assigning depositional environment interpretations to these non-marine and transitional clastics and to offer their associated characteristics as recognition criteria for rock units developed in other tectonic delta complexes (Friedman and Johnson, 1966) at other times in the geologic past.

B8: ALLUVIAL AND TIDAL FACIES OF THE CATSKILL DELTAIC SYSTEM

Cherty Onondaga Limestone exposures.
ON LEFT - colonial house, construction material Lower Devonian limestone.

Onondaga cherty, fossiliferous limestone.
Deep roadcut in Onondaga cherty, fossiliferous limestone. AHEAD - view of Catskill Front. The Front marks the eastern margin of the Catskill Mountains. It is cut by several narrow stream valleys (cloves) in which there are excellent exposures of Middle and Upper Devonian Catskill lithofacies. We will climb Kaaterskill Clove and observe rocks along the Rip Van Winkle Trail

Roadcut in cross-bedded, blue-gray sandstone.
Local term for this rock type is Bluestone.

ON LEFT Old, inactive quarries in Bluestone.

ON LEFT In distance, view of Kaaterskill Clove.

Cross small creek.
Rapids and low waterfalls in bed of creek due to well developed, horizontally bedded Bluestone ledges.

STOP 1. Gloria Dei Church (Episcopal)
This church, constructed in the late 19th Century, was built of fieldstone, most of Which is of local bedrock lithologies. The most significant of these are (1) polymictic pebble conglomerate, (2) grayish green, immature, medium-grained, sandstone, and (3) dark red, very fine grained sandstone and siltstone. In some respects this is as good an outcrop as any that you will see today.

Cross Kaaters Kill and begin climbing clove.
Just downstream from this bridge are very well developed pot holes and water falls, where the stream flows over Bluestone ledges.

Red and green Catskill lithofacies.
ON RIGHT, across Kaaters Kill - inter-beds of red and green Catskill lithofacies.

ON LEFT, up clove -Twilight Park
Twilight Park, a private preserve that was very fashionable in the late 19th and early 20th Centuries. It is still private, but less fashionable. The preserve is the type locality of the Twilight Park Conglomerate, the coarsest of the Catskill lithofacies rocks. The conglomerate appears to represent an ancient mountain front, braided stream deposit. You will see it in outcrop at Stop 3.

Road swings sharply left.
Cascade on right formed where tributary of Kaaters Kill flows over sandstone ledges.

STOP 2. View down Kaaterskill Clove
From this point it is possible to look east down Kaaterskill Clove. The cross-sectional profile is typical of high-gradient streams that are engaged in active vertical erosion. The Kaaters Kill is considered to be an excellent example of a short, high gradient stream that has managed to capture the headwaters of a longer lower-gradient stream flowing in an opposite direction. The elbow of capture is at Haines Falls, just west of this observation point.

Route 18 leading to North Lake Campsite,
Route 18 leading to North Lake Campsite, former site of Catskill Mountain House. The Mountain House, a resort hotel, was situated near the top of the Catskill Front, some 700 meters above the Hudson River. Exposures of cross bedded gray, conglomeratic sandstone and conglomerate may be seen on the trails around North Lake Campsite.

AHEAD - Hunter Mountain ski area.

STOP 3. Outcrop of cobble conglomerate
Outcrop of cobble conglomerate at base of one of Catskill lithofacies alluvial channels. This basal lag concentrate was apparently deposited quite near its source area. It is by far the coarsest exposure that you will see today.

ON RIGHT -Catskill lithofacies.

ON RIGHT -Catskill red beds.

Pratt Rock Park on outskirts of Prattsville.

STOP 4. Hardenburgh Falls
Walk northeast along unsurfaced side road to Hardenburg Falls.
At this point Bear Kill flows into Schoharie Reservoir. Beds here are assigned to the tidal channel and tidal flat facies. The tidal channel facies is represented by gray, cross-bedded, fossiliferous sandstones and the tidal flat facies by very dark gray, very thin-bedded, in part conglomeratic, shales. Lag-concentrates in both facies are rich in shallow marine brachiopod shells.

STOP 5A. Alluvial channel sandstone
On east side of road, exposure of alluvial channel sandstone resting on red over bank shale.

STOP 5B. Gray, cross-bedded sandstone
On east side of road, exposure of gray, cross-bedded sandstone of tidal channel facies with lag-concentrates of shallow marine spiriferid brachiopods.
BE VERY CAREFUL. THIS IS A NARROW SPEEDWAY WITH POOR VISIBILITY.

On right, in distance - large quarry
On right, in distance - large quarry from which much of stone for Gilboa Dam was taken. Completion of dam impounded waters of Schoharie Creek, forming Schoharie Reservoir, a part of New York City water supply system.

View north down Schoharie Valley.
Note even crest of hills flanking valley, a result of stream dissection of nearly horizontal Devonian strata

STOP 6. Display of seed-fern stumps
Display of seed-fern stumps taken from quarry just to southwest. Some 200 specimens were found during the quarrying operation. These seed-ferns are thought to have grown to heights of some 18 meters in swamps along the seaward margin of the Catskill alluvial plain during late Medial Devonian time. They were buried during a minor oscillation of the marine shoreline in tidal channel or bar sand deposits.
2013: Stumps were apparently moved here, from the other side of the bridge, as the excavation took place in 2010...OHM

STOP 7A. Alluvial channel sandstones
These alluvial channel sandstones mark the top of an excellent section of some 185 meters, consisting almost entirely of rocks of alluvial origin. Many of these sandstone ledges show an interesting upward progression of change in texture and sedimentary structures.

Hamilton Group
To left (north), in distance, dip slopes of Hamilton Group strata.

Tidal channel facies.
ON RIGHT - high on outcrop - tan sandstone, much lighter in color than sandstone in remainder of exposure, assigned to tidal channel facies.

STOP 7B. Over bank facies root stigmaria
At the driveway are alluvial overbank facies root stigmaria and a highly calcareous overbank "evaporite" bed. A short distance downhill is a compound alluvial channel and laterally equivalent overbank silt stones.

Catskill lithofacies
Beginning of series of road cuts channel and overbank rocks in Catskill lithofacies

B9: ENVIRONMENTAL GEOLOGY and VISUAL POLLUTION OF THE LLOYD NUCLEAR POWER PLANT SITE
Stephen J. Egemeier
State university of New York College at New Paltz
A History of Site Study
In November 1971 the N.Y. Atomic and Space Development Authority released an anonymous report by Dames and Moore (a consulting engineering firm) entitled : "Consultation and Geologic Evaluation Site Suitability Studies: Hudson River Valley between Albany and Newburgh, New York." The report studied nine sites, two adjacent to the present Lloyd site. Of the nine sites, 5, or more than half, are rated as most favorable for additional study.
Starting in March 1975, R. Waines and I decided to have a quick look at the regional geology of the site. We started by walking the Dames and Moore cross section and studying all outcrops within a few hundred feet of the trace of the section. Many man days were spent and over 100 observations recorded for the 3 mile section. We then checked critical outcrops mentioned by Dames and Moore and did a general reconnaissance of the area. A broad picture has emerged and is shown in our tentative cross section in Fig. 5.
The aim of this field trip is to show you some of the major points of geologic interest and also show some of the areas of controversy. There is ample room for supposition and argument until adequate study is completed.
The site geology is difficult to determine due to a lack of good marker beds, a lack of diagnostic fossils, and lack of continuous outcrop. Recently, many people have started working out the geology, however, a considerable effort will be required to gain a detailed understanding of the site geology. There is still a lot to be done, for example, as yet there is no published detailed stratigraphic column of the site area. Up until now there had been no economic reason to study this area.
Harvey K. Flad
Vassar College
The analysis of the environmental impact of a noxious facility implies the need for assessment of aesthetic and social impacts as well as the physical impact upon the land, air, water, and biota. Aesthetic impacts, such as upon the visible scene, have not been studied in detail for the environmental impact statement of the siting of a nuclear power plant at Lloyd, N.Y.
This lack of detailed concern is unfortunate: the changes due to the viewscape are obvious and of a degree of magnitude which demand their attention. Although the assessment of aesthetics is complex and fraught with problems of subjectivity, nevertheless transmission tower and power plant design and siting must be implemented in consonance with the overall human environment, indeed, Federal and State legal rulings reflect an increased awareness and justification tor aesthetics as a form of environmental control. (Flad, 1974) Measurement of aesthetic impact of nuclear power plants is possible (Burnham, 1974). This paper and field trips will deal with some of the outstanding aesthetic concern (cooling tower height and plume, transmission pylons and rights-of-way, and historic and cultural sites) with respect to varying viewsheds of the Lloyd site viewscape.
Conclusion
A concern for the aesthetic impact of a nuclear power generating facility is not a secondary matter. Not only is it mandated by the Nuclear Power Regulatory Commission in pursuance of the goals of NEPA, but it is an appropriate measure of the goals and purpose of the electric utility or state agency which originates the proposal for a site and employs a consulting firm to do the EIS. Some concern was shown for the biotic impact upon the John Burroughs Sanctuary (National Audubon Society, 1974), but its aesthetic impact on this historic site and on the historic sites along the Hudson River (Roosevelt, Vanderbilt and Ogden Mills Estates) was less apparent. The accompanying road log to the field trip details some on the viewshed and aesthetic amenities of the Lloyd site and its impacted Mid-Hudson region.

B9: ENVIRONMENTAL GEOLOGY and VISUAL POLLUTION OF THE LLOYD NUCLEAR POWER PLANT SITE

Typical urban strip
On the way, one may notice typical urban strip development, including two important historical buildings as noted. The West Indian grocery on the right is an urban landscape indicator of ethnic change in the Poughkeepsie Central Business District.

Glebe House
The Glebe House is on the right. Built in 1767 by the Poughkeepsie and Fishkill congregations of the Episcopal church for their minister, it is the oldest brick house in Dutchess County. The first permanent Episcopal minister, Reverend Beardsley, was exiled during the Revolutionary War for his Tory sympathies. It is now maintained by the Dutchess County Historical Society and the Junior League of Poughkeepsie.

Clinton House
The Clinton House is a State historic site, named in honor of the first governor, who made his headquarters in Poughkeepsie when it was the temporary state capital from 1777 to 1783. Originally built c.1765, it was rebuilt and enlarged in 1783 by Udny Hay, purchasing agent for the state, with assistance from artisans from the Continental Army sent by General Washington.

STOP 1. College Hill Park.
The largest park in the city of Poughkeepsie, College Hill Park is located on the highest point in the city (375 feet). Excellent views south and southwest of Poughkeepsie and its environs, as well as the bridge and the Hudson River; farther south the Fishkill or Breakneck Ridge can be seen. West and northwest lie the Catskills; the Lloyd power plant site lies among the hills to the northwest. The park is named for a school which existed at this site in the mid-nineteenth century. After the school and subsequent plans to use the buildings had failed, William W. Smith, of Smith Brothers cough drops in Poughkeepsie, donated the land to the city in 1892. The Greek Doric designed stone solarium on the crest of the hill was built in 1935-6.

Open reservoir on left.
This open area affords the best view northwest across the Hudson River towards the Lloyd site. The open reservoir was formerly the main water supply of the city.

Michael's (Joseph's since 2011) Restaurant on right.
This building was used as the tea room for Val-Kill Industries, established in 1927 by Mrs. Eleanor Roosevelt. Eleanor Roosevelt's cottage (Val-Kill) still exists one quarter of a mile east of this point (on a dirt road 150 feet north of the intersection of Route 9G and Creek Road). At the cottage Mrs. Roosevelt organized a cottage crafts industry which attempted to reintroduce the crafts of furnture making, pewter smithing and hand-weaving as a local economy. The cottage is presently under consideration for inclusion in the Federal Register as a National Historic Landmark.
If a power plant is built at Lloyd, the electricity will be shipped by high tension transmission lines along a power line corridor that traverses this property; the lines and pylons will dominate the Val-Kill skyscape.
2013: In 2011 Joseph & Diana Wilson open Joseph’s Steakhouse as a classic New York style Steakhouse in Hyde Park. The Steakhouse property was formerly owned by Eleanor Roosevelt as the Val-Kill Tea Room.

Homestead Market on the right.
This property until recently was the last remaining dairy farm in the Poughkeepsie-Hyde Park urban area.

William Stoutenburgh House, on left.
One of the only two remaining early Dutch stone houses, built probably in 1750 by William, son of Jacobus Stoutenburgh, the first settler of Hyde Park. It was fired upon by British ships in October 1777. Otto Berge, who was foremost maker of antique reproduction furniture at Mrs. Roosevelt's Val-Kill furniture shop, lived in this house for over forty years until 1975.

STOP 2. Vanderbilt Estate
The Vanderbilt Estate was built by the grandson (Frederick) of Cornelius (Commodore) Vanderbilt in 1895. The building is a classic by the architectural firm of McKim, Mead & White.
A short walk from the parking lot to the mansion and surrounding lawns. From the edge of the bluff a magnificent view west across the Hudson River.
Viewing southwest, one can have a clear sight-line towards the Lloyd site, exactly 3 miles away. All four stacks will be visible.

View west and northwest of the Catskills.

Hyde Park Playhouse
Directly across the exit are the former estate horsebarns, now the Hyde Park Playhouse, famous for summer theater.
2013: Burned down on April 28, 1987.

Bergh-Stoutenburgh House on left.
The second of the two remaining stone houses in Hyde Park, built before the Revolutionary War. Its gambrol roof is unusual. Now recycled and occupied by the Green Frog dress shop.
2013: Later, home to Edo Sushi, a Japanese restaurant. The restaurant closed its Hyde Park location and moved to nearby Poughkeepsie in the fall of 2012. The Bergh-Stoutenburgh House is currently unoccupied.

Cleared Lot
On the left (next to Gasland gas station) is a cleared lot ... all that remains of the third of the previously three existing pre-Revolutionary stone houses.

STOP 3. F.D.R. home and museum.
The birthplace of the 32nd President of the United States, and home for himself and family. The 94 acre site contains a museum and library as well as the graves of both Franklin and Eleanor Roosevelt. Originally built c. 1826, the wings were added in 1915 by F.D.R.
The view from this home of 3.1 miles of the Lloyd site is only slightly obscured by a range of hills in the Lloyd region. Stacks numbered 3 and 4 of the proposed Lloyd site plan would definitely be seen in any case.

Barkers shopping center on right.
After intensive discussion, stone walls were preserved.
2013: Now called Hyde Park Mall, it was renovated in 2010.

Culinary Institute of America on right.
Formerly St. Andrew's Novitiate, a Jesuit seminary since 1903. American Trappist Monk Fr. Thomas Merton, author of The Seven Storey Mountain and numerous poems and essays, is buried here. Purchased by the C.I.A. in 1970 as a college for fine chefs.

Hudson Valley Psychiatric Hospital on the left.

Marist College on the right.

Austin Glen formation
The curved roadcut just west ot the bridge reveals a section interbedded shales and graywackes mapped as Austin Glen formation on the 1970 N.Y. State geologic map and by Dames and Moore, 1975. On the west (left) side of the cut several faults are visible. Note that an individual bed may vary in thickness even over short distance. We will see a lot ot outcrops that are frustratingly similar to this one.
Good marker beds are non-existent and what poor markers there are are useful only in very small areas. Fossils are rare and usually nondiagnostic. Thus geologic mapping in the Lloyd area is a slow and arduous task. All the rocks in the Lloyd area are Ordovician in age.

STOP 4. Steeply dipping graywacke.
On the 1970 N.Y. State Geologic map this is mapped as Quassaic although this sequence differs trom the map's description of the Quassaic. Dames and Moore map this outcrop as Schenectady Formation, just south of here, along strike, they map the same rocks as Quassaic Sandstone. These rocks may be Quassaic or may overlie the Quassaic.
This outcrop is a section of the east limb of an asymmetric syncline with it's east limb overturned. On the east and of the outcrop the rocks dip east steeply and are overturned. On the west end of the outcrop the rocks dip steeply west and are right-side-up. The fold axis is just west of here, perhaps along the Black Creek (i.e. near the bridge).
If we were to travel to the west we would not see a repeat of the strata exposed here, but would see mostly shale. Thus it is assumed that a fault is buried beneath the till along Black Creek. The fault could be a thrust dipping east that formed contemporaneously with the folding or it could be a steeply dipping normal fault dipping east as shown by Dames and Moore, 1975. Minor faults in this outcrop might suggest this.
I prefer the former interpretation and Dames and Moore prefer the latter. As the fault is buried neither answer can be proven at this time.

East dipping shales
Note shales on right side of road, gently dipping towards east, also outcrops on left in pasture of east dipping shales.

Revolutionary age cemetery on left.

Cross Black Creek.
Note waterfall on right. Outcrops of gently eastward dipping shales with interbedded graywacke.

STOP 5. West limb of a syncline
We will stop on the east shore of Chodikee Lake and hike to the east across the west limb of a syncline to the axis of syncline. STOP 4 was on the east limb of this same fold.
To the west of where we will park the busses is Chodikee Lake. Based on outcrop along the south shore of the lake (near the waterfall for example) it appears that the bedrock under the lakes is mainly shale with some interbedded graywacke. The low ridge just west of the lake is mainly massive graywacke. The ridge is bounded on the east by a shear zone that follows a swampy valley.
As we walk east you will note that the exposed bedrock is mostly graywacke. Shales are found in some of the valleys beneath the soil. The axis of the syncline is just west of a cliff formed by graywackes of the east limb of the fold. If we were to continue to the mountain summit we would climb valley and ridge topography with very little shale. Thus the shales beneath Chodikee Lake do not seem to repeat on the east limb. This again suggests that the fold is faulted. The extreme asymmetry of the fold and the general pattern of thrusting from the east suggest that the fault would be a reverse fault.
The rocks that crop out at the axis of the fold at this point are the youngest rocks of the Lloyd site. Their exact age is not certain as diagnostic fossils have not been found in this area. I have found fossils in float and am hopeful that I will find some in place.

STOP 6. View across lake
View across lake towards site of nuclear power plants and cooling towers, less than one mile NW of east shore of Chodikee Lake. Notice meteorological tower directly west (at southern end of site). The tower is 90 meters tall; thus the cooling towers will be almost two times as tall, as well as much more massive.

Land use that may be affected
As examples of the agricultural land use that may be affected by land pressures due to growth, or to climatological change; note the vineyards and orchards to right side of road.

Outcrop on left.
Outcrop shows slightly metamorphosed slaty shales and siltstones, with foliation steeper than the eastward dip.

Agricultural land use typical of region
Note new plantings at apple orchard on left

Examples of architectural individualism
Note house with sculptured gargoyles on left, and building with used car parts sign on the right side of Route 9-W.

Outcrop of shales.
Stop sign, Turn left onto Route 9-W northbound. Outcrop on immediate left at stop sign is another good example of shales.
2013: Now there is no access to northbound lane here. Hence, we return along North Road to where we can get into the northbound lane.

Town of Esopus sign on right side of highway.
Two nuclear plants are projected to be sited on the town line between Esopus and Lloyd, less than two miles directly west. Such exact siting is to spread the economic impact over two towns.

Mother Cabrini Retreat House on right.
Many former Hudson River estates have been converted to monasteries, seminaries, or retreat housed by various churches and orders, such as the Holy Cross, Christian Brothers, and Marist Brothers. Excellent views of the Hudson River valley looking eastward from these properties.

Outcrop on right. Extremely steeply dipping.
Excellent example of an overturn, note ripple marks overturned.

STOP 7. LUNCH STOP
At driveway (entrance) to Cabin of John Burroughs, noted Catskill naturalist and author of many books on natural history in the 19th Century, stop for short walk to lunch stop area.
Bus will stop briefly to offload passengers for a short walk alongside outcrops alongside road and will meet us a Gordon Preserve Park (along Black Creek in the Gordon Memorial Woods). Watch it -- Poison Ivy is abundant in this area.
The buses will stop near the crest of the ridge where the bedrock is clearly overturned. We will walk down the road to the Black Creek where several ledges in the stream dip south. Just west of the stream bedrock dips east. The Black Creek is following the axis of the syncline along this reach. We are on the axis of the syncline at a point stratigraphically much lower than at the Highland Training School, STOP 5. This is one of the most accessible places to view the syncline. Even so, we cannot trace beds from one side of the fold to the other because of a fault.
Southeast of here on the road that parallels the creek is Villa Valley. At Villa Valley another fault is exposed in outcrop. It dips east at a slight angle to bedding and is apparently a thrust. It strikes north and crosses Floyd Ackert Road about half a mile east of here.
Lunch can be eaten along the banks of Black Creek or the dammed up swimming pool on the creek. Tour participants are encouraged to seek additional evidence from neighboring outcrops, or commune with nature in the manner of John Burroughs.

Note very gentle dips on outcrops.
Popletown Road becomes a gravel road as it steeply climbs 350 feet to the peak of Shaupeneak Mountain.

STOP 8 Western Union communications tower
From the clearing afforded by the Western Union communications tower facilities, note the view South and Southwest of the Lloyd nuclear site. The nuclear plants and cooling towers will be approximately four miles directly south from this peak, in the center of the presently relatively unspoiled and aesthetically pleasing view.
There is an OUTHOUSE available at this stop.
A short walk to various outcrops on peak; especially noteworthy are the red cherts. Return to bus for trip hack down mountain to Old Post Road.
This stop is at the northern end of the syncline we saw at Black Creek and the Highland Training School. We are several thousand feet stratigraphically lower than we were at the training school.
The stratigraphically lower part of the fold is far more gently folded and is not overturned. Several north striking shear zones cut the structure and at least one can be seen in outcrop along the cliff to the east.
Just north of a former community antenna system rocks crop out that fit the description of Quassaic Quartzite as given on the Geologic Map of New York, 1970. They are overlain by thousands of feet of rocks that do not fit the description. The description from the 1970 N.Y. State Geologic Map key is as follows:
"Quassaic Quartzite - thick bedded red and green quartzites and greenish-gray sandstones, conglomerates with pebbles of red and black chert, shale and limestone."
Dames&Moore in their 1975 report have changed the description of Quassaic. Their map key states:
"Quassaic Sandstone: Grey to brown calcareous protoquartzite and subggraywacke with occasional conglomeratic zones of limestone, chert and shale pebbles."
The point of this trip is not to pick hones over stratigraphic nomenclature, but to get a general idea of the environmental geology of the Lloyd Site. The proposed nuclear power plant complex represents the first time there has been significant economic reason to work on the geology of this region.

Historic one room school house
Note historic one room school house building on right which has been recycled into a home.

STOP 9. Sturgeon Pool of the Wallkill River.
Sturgeon Pool is part of a hydroelectric installation of Central Hudson Gas andElectric Corporation.
Dames & Moore 1975 have mapped the northern half of the pool as Snake Hill formation. The eastern shore at the pool is massive graywacke and the hill on the west is largely shale. Thus on the 1970 N.Y. State Geologic Map the eastern shore is mapped as Austin Glen and the west as Normanskill (Snake Hill).
As an example of the visual imprint of electric power transmission lines and pylons in the skyscape, note the 345 kV lines across the lake at the spillway. Lines which carry greater loads (765 kV) require higher pylons and are therefore even more apparent in the landscape and skyscape.

Outcrops on left
Shales with interbedded thin graywackes.

1816 stone Church on right.

Thick graywacke beds interbedded with shale
As we drive south along Sturgeon Pool, you will note thick graywacke beds interbedded with shale. Dames & Moore show a thrust fault relationship between the graywackes and shales.

STOP 10. Electric power substation
Central Hudson Gas and Electric Corporation electric power substation
Offload from busses in the C-H parking lot and walk down Route 213 on left side of road. WATCH FOR TRAFFIC. A small fold is in evidence, as well as interesting facies changes of graywacke and shale. Note as you walk along to road cut that at least one 2 ft. thick massive graywacke bed develops shale interbeds to the west. Generally, there is a facies changes in the Lloyd area with graywackes on the east and shales to the west. We will walk up the bank and through the woods to get to a unique outcrop. There is no trail so watch your step.
This outcrop is described by Dames and Moore in the 1975 report on page 31 as follows:
"4.1 Dashville thrust
"Perhaps the most spectacular and (from a classical viewpoint) unexpected structure in the region is the Dashville thrust. This feature is exposed along Rt. 213 between Rt. 32 and Rifton, and is best preserved in the hillside below the Woodcrest School. There, upward from road level, occur (1) moderately folded Snake Hill sandy shale, (2) 20 ft. of thrusted slices of Schenectady Formation and Quassaic sandstone, (3) three feet of tectonically mixed Snake Hill and Quassaic and, (4) about 200 ft. of Snake Hill Formation. The investigators feel that (1) the amount of evident thrusting (2) the observed intermixing of Quassaic and Schenectady, (3) the thinness of the characteristically thick Quassaic-Schenectady section, and (4) the overlying zone of mixed Quassaic-Snake Hill all argue for a tectonic sliver of Quassaic and Schenectady caught in a major thrust of Snake Hill over Snake Hill."
The names used by Dames and Moore refer to lithology as follows (abstracted from their map key):
Schenectady formation: thinly bedded subgraywacke interbedded with siltstone and silt-shale.
Quassaic sandstone: Protoquartzite and subgraywacke with occasional conglomerate zones.
Snake Hill Formation: Silt and clay shales interbedded with thinly bedded siltstone.
Look at the outcrop and come to your own conclusions. Is what you see due to thrusting or some other cause?
Continue to "Perrines Bridge," an old covered bridge across the Wallkill circa 1844 (Ulster County Historical Site).

STOP 11. Possible seismicity along linear?
Events similar to earthquakes have been reported by several homeowners in this area. The reports are only from those who live along a line parallel with the base at the ridge just east ot the road intersection. The reports seem to be aligned along a N-S linear feature that shows up on landsat photography. The linear also shows up on topographic maps and on the ground as a series of aligned valleys. This linear is one of the more noticeable of s e veral subtle N-S linears that cross the site. This linear is apparently at least 8 miles long.
Where one of the linears crosses Shawpeneak Summit sheared graywackes crop out on the southeast side of a valley that marks the linear. Dames and Moore drill hole 2 is 500 ft. east of the linear. The hole was drilled to 249 ft. and several broken zones were reported. It seems most reasonable to conclude that his linear is a fault.
People who live along this alignment have reported events that may be earthquakes. The linear passes through one of the proposed nuclear power plants. A summary of the reported events are listed in the appendix.

ASDA (ERDA) Meteorological Station on the right.
Climatological data is gathered at ground level and from the 90 meter tower noticeable from the road.

STOP 12. Sorbello's greenhouses and onion farms
Situated on the deep rich muck soils, Sorbello's greenhouses and onion farms are located in the very heart of the proposed nuclear site at Lloyd. The land use plan proposes the first two plants and cooling towers to be located just to the north in the same swampy soils. View south and notice the height of the ASDA-ERDA meteorological tower (90 meters) and recall that the cooling towers planned for this site are almost two times as tall and massive enough at their bases to essentially fill the valley east-west.

B10: ENGINEERING AND ENVIRONMENTAL GEOLOGY OF THE HUDSON VALLEY POWER SITES
William D. Lilley
Associate Generating Facilities Analyst (Geology)
Office of Environmental Planning
NYS Department of Public Service.
Empire State Plaza
Albany, New York 12223.
Claudia Assini
Geologic Consultant to the NYS Geological Survey
for the Indian Point Project.
The four main types of electric generation facilities that will be available in the next 25 years are coal, oil, nuclear and hydro. Each type has significant environmental impacts requiring detailed geologic and environmental studies. The purpose of this field trip is to identify some of the geologic and environmental considerations involved with siting various types of facilities.

STOP 1. Danskammer and Roseton, Marlboro, New York
(1) Danskammer - Central Hudson Gas & Electric Corp. Plant - Oil Fired - 531.9 MW - 66.3 Acres Plant Site
Units 3 and 4 of the Danskammer Point Generating Station are the subject of a notice of intention by the Federal Energy Administration to issue a prohibitive order that would require conversion of those units from residual oil to coal.
Unit 3 was first placed in commercial service in October 1959 and Unit 4 in September 1967. Central Hudson currently has $57,000,000 invested in the two units; $5,000,000 represents the cost of converting these units from coal-firing to oil-firing in 1970 and 1971.
These units were originally designed with coal as their primary energy source. In the late 1960s, however, because of the rapidly rising cost of coal, the deteriorating quality of the coal economically available, coal delivery problems, increasing costs associated with coal unloading and handling and ash disposal, increasing concern about the environmental impact of coal burning, and the very attractive prices for fuel oil being offered by some of the major oil companies, the decision was made to convert these units to oil firing. At that time the oil companies indicated to the company that oil prices would be stable for a long time and that ample oil supplies would be available. Indeed, after competitive bidding, the company entered into an advantageous contract for fuel oil at a fixed price; that price prevailed from 1968 to the oil embargo in 1973.
Because of the foregoing factors and the severe space limitations at the station, the company decided that the conversion from coal to residual oil would be permanent, with no consideration for reconversion to coal-firing. Consequently, major modifications were made that resulted in these units becoming exclusively oil-fired.
The major problems of air quality impact and waste disposal associated with conversion have not yet been resolved. At present there are air quality violations in the area of the plant, and conversion to coal could only worsen this situation. The Environmental Protection Agency has yet to make a decision on the FEA coal conversion notice.
(2) Roseton - Central Hudson Gas & Electric Corp. Plant - Oil Fired - 1242 MW -133 Acres in Land Use
Environmental Impacts:
(a) Aquatic and Water Quality The plant is under EPA orders requiring cooling towers. The company has requested a variance to prepare studies to prove the impact of cooling water intake and discharge location and operation is insignificant.
(b) Air Quality Violations of the Federal primary ambient SO2 standards have occurred in the vicinity of the plants. The New York State Department of Environmental Conservation has ordered Central Hudson to burn lower sulfur fuel costing $8 million more per year. Public Service Commission staff believes that the severe downwash problems due to the short stacks, compounded by the high terrain at these facilities, are creating the air quality problems. The stacks were designed in response to a State agency request to limit the aesthetic impact of the facility.
(c) Noise Numerous complaints have been made about noise generated by the Roseton Station. The noise problem is a result of the short stacks. The company has attempted to increase exit velocity of the stack gas to improve air quality. The company has failed to solve the air problem and now has a noise problem.

STOPS 2 AND 3. Storm King-Cornwall Project
Storm King-Cornwall - Consolidated Edison Company of New York. Inc. - Pumped Storage - 2000 MW Proposed 1965. Planned Operation 1988
History
The ten-year legal battle between the Scenic Hudson Preservation Conference and Consolidated Edison Company of New York. Inc. over the Storm King project anticipated the environmental litigation that developed in the late 1960s and early 1970s, resulting in NEPA and subsequent Federal and State legislation governing air and water quality. It also highlighted a new area in the legal practice -- environmental law. The turning point in the Storm King case came in late 1965 when the United States Court of Appeals for the Second Circuit ordered the FPC to reopen proceedings after granting Consolidated Edison a license to build. The FPC was instructed to weigh aesthetic and other environmental values in the utility's proposal and to explore alternative means for meeting the project's objectives. In 1966 Consolidated Edison amended its plans to put the powerhouse entirely underground, thus eliminating the cut in the face of Storm King Mountain, and making the trail race less visible. Since licensing hearings before the FPC have been suspended until after October 1, 1976, it is not possible to accurately predict what constraints may arise from these hearings. Constraints could include possible reduction of biological impact of the plant. This may require fish protection devices or other mitigating measures, and continuation of present environmental studies or the addition of new studies to determine plant impact on aquatic population may be required.
In March 1976, at the request of the New York State Public Service Commission, Consolidated Edison submitted a report of a restudy of the need for, and economic justification of, the Cornwall project. The report says the underground pumped storage plant's capital cost would be about $1 billion and alternatives to the project would require an investment of $1.4 billion to $3.2 billion.
Engineering Geology
The Pagenstecher Creek fault lies to the northwest, separating the Highland's granite from sedimentary rocks to the north. This fault strikes northeast-southwest and dips steeply to the southeast. The surface and the Pagenstecher fault intersect at a minimum distance of 8,000 feet from the reservoir site; and the fault dips beneath the reservoir at depths between 6,000 feet and 29,OOO feet. The claim was made that the Pagenstecher Creek fault might be reactivated by the weight of the water as it rises and falls in the reservoir. The FPC found that the thousands of feet of sound, tight, granite rock and gneisses underlying the project are capable of sustaining any loading without movement of the Pagenstecher Creek fault.
The hazards to the Catskill Aqueduct from powerhouse excavation and vibrations caused by blasting were raised by New York City and Scenic Hudson. Construction of the powerhouse would require removal of approximately 254,000 cubic yards of rock. After several geologic studies and witnesses were heard on the subject of rock stress, the FPC concluded that the evidence in the record indicates that the probability of damage to the Catskill Aqueduct is remote.
2013: Update - 1980 (December 20) – Scenic Hudson and Consolidated Edison reached a settlement in which Consolidated Edison agreed to terminate its plans for Storm King Mountain, reduce fish kills at Indian Point and other power plants along the Hudson River, and establish a research fund for the Hudson River ecosystem in return for not having to install closed-cycle cooling towers at existing plants.

STOP 4. Ramapo Fault System, Stony Point, New York
The Ramapo Fault System, shown in Figure 7, extends for more than 50 miles northeast from Peapack, New Jersey to the Hudson River at Stony Point, New York just west of Indian Point. Along this trend, to at least the New York State border, the Ramapo Fault System is a zone in the Newark Basin. The term Ramapo Fault has been applied to the structure north of the New York State line where the fault system continues northeastward, but is divided into several major splays trending subparallel to each other and passing into the Precambrian Hudson Highlands on both sides of the Hudson River.

STOP 5. Indian Point, Buchanan, New York
Nuclear Unit 1 - Operational 1962, 260 MW (the second commercial reactor in the United States) -Shutdown in 1974 due to inadequate emergency core cooling system.
Nuclear Unit 2 - Operational 1976, 873 MW, has applied for its full operational license. Owned by Consolidated Edison Company of New York, Inc.
Nuclear Unit 3 -Operational 1978, 965 MW, has applied for its testing operational license. Owned by PASNY.
Seismic Analysis
The hearings on seismic safety of Indian Point have been held before the Atomic Safety and Licensing Board. The New York State Atomic Energy Council, Citizens Committee for the Protection of the Environment, Consolidated Edison, and NRC were parties in the proceeding. The following issues are in controversy:
(1) Does the Cape Ann earthquake of 1975, or any other historic event, require the assumption, in accordance with 10 CFR, Part 100, Appendix A, of a Safe Shutdown Earthquake for the Indian Point site greater than a Modified Mercalli Intensity VII?
(2) Should the ground acceleration value used for the design of Indian Point Unit 1, 2 or 3 be increased?
(3) Is the Ramapo Fault a capable fault within the meaning of Appendix A, 10 CFR, Part 100?
These hearings were completed this summer and decisions on these issues are expected this fall. The decision could effect the seismic analysis used in siting all nuclear plants.
At present, Consolidated Edison is undertaking extensive geologic and seismic studies of the Ramapo Fault System.
Environmental Impact
The major fishkills at Indian Point plants in the winter of 1964-1965 served to high-light the potential impacts of power plants on aquatic life. These fishkills added controversy to the Storm King hearings and the requirement for cooling towers at many power plants to protect aquatic life. At present. Consolidated Edison is under orders from NRC, at the request of EPA, to install cooling towers at Unit 2 by 1979 and at Unit 3 by 1981. Consolidated Edison has requested a variance on the tower requirement. The people of Buchanan, New York and local officials have opposed cooling towers due to the noise, visual impact and impacts on salt drift. Consolidated Edison has requested time to prepare impact studies.

STOP 6. Quarry Site, Wappinger's Falls, New York
Proposed Coal Plant - 700 MW - Power Authority of the State of New York
The quarry site is an alternative to the Arthur Kill site on Staten Island, New York. The plant would supply for the MTA. This would relieve some of the load carried by Consolidated Edison. This site is subject of an as-yet-to-be docketed Article VIII application pending before the New York State Public Service Commission.
Engineering Geology
This site is located next to one of the largest limestone aggregate quarries in the United States. On June 7, 1974 an earthquake of magnitude 3.3 occurred at the quarry site. All available evidence indicates that this earthquake sequence, and possibly past earthquakes in the same area, may have been triggered by crustal unloading associated with quarrying operations in the presence of high horizontal stress.
Environmental Geology
The coal plant proposed to be built will have SO2 stack gas scrubbing equipment. The only type of SO2 scrubbing equipment the engineers consider reliable enough to meet present air quality standards is a nonregenerable scrubber system, would produce over one million tons of toothpaste-like material requiring stabilization and disposal. The disposal options are quarries, the ocean or the Bahamas. The economic and environmental impacts of each option have yet to be fully explored.

C6: WALKING TOUR OF HISTORIC FISHKILL, NEW YORK
Harvey K. Flad
Department of Geology & Geography
The village of Fishkill was the scene of a number of important events during the Revolutionary War, and remained a serene rural village until the recent suburban growth of southern Dutchess County. Settled by the Dutch a few years after the granting of the Rombout Patent of 1685, Fishkill soon became an important center of local agricultural activities.
Participants of the walking tour will have a chance to enjoy the human scale of heritage that remains in historic Fishkill.

C6: WALKING TOUR OF HISTORIC FISHKILL, NEW YORK

Vassar Farm
On right is Vassar Farm, a 541 acre "island" of open space in the rapidly developing area. A concept master plan by Sasaki Associates, 1975, is presently underway to create a conservation area of over 300 acres.

IBM Development laboratories
IBM Development laboratories on the former Boardman-Kenyon farm.

View the Catskill Mountains
From this height one can view the Catskill Mountains across the Hudson River to the west. As one proceeds west on Spackenkill, note the development of single family dwellings on the left known as Hagantown. Vassar Farm property on right.

Spackenkill High School on left.
A confusion of architectural styles of the single family dwellings is evident (for example the peculiar "mansard" roof lines), as well as a lack of concern for appropriate front yard plantings along a busy highway. "For Sale" signs indicate continued growth.

Oakwood School on left.
This school is the oldest private coeducational boarding school in the United States, begun by Quakers in 1796.

South Road plant of IBM
As you cross the bridge ahead is the South Road plant of IBM, where much of IBM's hardware is constructed. IBM is the largest single private employer in Dutchess County. The summer home of Samuel F B.Morse. inventor of the telegraph, is just to the north of this plant.

I.B.M. Country Club on left, followed by Hudson Valley Block aggregate.

On right, low cost modular homes.

Poughkeepsie Asphalt. Inc
Poughkeepsie Asphalt. Inc. (bituminous concrete) on right.
2013: Good image of plant when it was operating, is on Google Earth, 2004.

Lone Star Industries - crushed stone
Lone Star Industries, New York Trap Rock Corporation Clinton Point Plant; Dutchess Quarry and Supply, on right. Major source of crushed stone (dolomite) (see: River Guide); also mentioned as potential site for nuclear power plant, although small earthquakes have been noted here.

George Clinton estate
Entrance to estate owned and occupied 1804-1812 by George Clinton, then vice president of the United States. No longer existing; owned by Lone Star Industries.

Mt. Alvernia seminary of the Franciscan Friars on the right.

STOP 1. View south.
View of Fishkill plains nestled at foot of Highlands; a strategic staging and transport center for the Continental troops.

Dutchess County Park on right.
Recently purchased by the county from Children's Aid Society in New York City, it was known as the Bowdoin-Vanderbilt Camp. During the past year geography students from Vassar College, landscape architecture students from Cornell, and ecology students from S.U.N.Y. Purchase studied the environment and social uses and created plans for the consideration of the county legislature. The work was coordinated by the Dutchess County Cooperative Association and County Planning.

Cross bridge over Wappinger's Creek.
On right is Wappingers Creek estuary; across railroad tracks and Hudson River see Danskammer power plant. The mouth of Wappinger's Creek was an important loading dock for produce from the farms of Dutchess County during the period just before the Revolutionary War. Dutchess County supplied much of the wheat for the Continental army.

STOP 2. Wappingers Falls
Walk from cars to bridge on E. Main Street over looking Wappingers Falls. The falls was a major source of power for textile dying firms (the bleachery); the village retains many fine nineteenth century facades.

Mesier Park.
Turn left into parking area at sign for police station. Mesier Homestead, c.1750. Peter Mesier, a New York City merchant, bought the grist mills originally built by the Brewer brothers in 1777. Because Mesier held Tory sympathies, his store (operated from part of this house) became the scene of several "Wappingers Tea Parties" where Whigs and patriots broke into Mesier's house and store and "protested" his price of tea by "consuming large quantities of liquor."

The Dutch Reformed Church
The Dutch Reformed Church was originally built in 1731 although it was substantially rebuilt in 1786 after its active use during the Revolutionary War. During the Revolutionary War it served as the seat of the Provincial Congress from September 1776 to February 1777, after it had fled from New York City and White Plains, making Fishkill the capital of New York for that period. Later in the war the church was used as a military prison and was the scene of the "escape" of Enoch Crosby, patriot spy, which became the basis for John Fenimore Cooper's novel The Spy.

Trinity Church
Trinity Church, built in 1768, is the county's oldest church building still in use. During the Revolutionary War it was first used for a meeting of the Provincial Congress; later it became a military hospital.

STOP 3. Assemble for "Walking Tour of Historic Fishkill"
(approximately 1.5 hours). Of the many interesting buildings, two are of greatest interest: the First (Dutch) Reformed Church and Trinity Church.

STOP 4. Van Wyck-Wharton House
Van Wyck-Wharton House, at Interstate 84 and Route 9, was built in 1733, with a major addition twenty years later. During the Revolutionary war the house was used by the Continental army and quartermaster department officers stationed at the Fishkill camps, and was also the scene of several courts martial. Built by the Van Wycks, it has also had the name Wharton attached to it as it was the inspiration for the Wharton House in James Fenimore Cooper's novel The Spy.

C7: STRATIGRAPHY AND STRUCTURAL GEOLOGY IN THE HARLEM VALLEY, S.E. DUTCHESS COUNTY, NEW YORK*
James M. McLelland
Colgate University
Donald W. Fisher
New York Geological Survey
The purpose of this field trip is to provide familiarity with the stratigraphy and structure of the Amenia-Pawling portion of the Harlem Valley in eastern New York State. Emphasis is placed upon stratigraphic relations of the Wappinger Group (Dana, 1879) which represent the Cambrian-Ordovician carbonate shelf sequence in this portion of the Appalachians. Additional stops will be made to examine the Poughquag Quartzite, the Walloomsac Schist, the Everett Schist, and Precambrian units of the Hudson Highlands, all of which are integrally related to the regional geology.
It should be understood that the structural framework and geologic history of this area have not been clearly deciphered. As in other parts of the Taconide Zone (Zen, 1972), complex polyphase deformation, regional metamorphism, and limited exposure have combined to leave scanty evidence of a protracted geologic history. A great deal more detailed work is required before the Harlem Valley area is well understood. It is our hope that this trip may arouse sufficient interest in the regional geology so that others will decide to undertake further field studies in the area.
Acknowledgments
We thank the following individuals for their roles in enhancing our understanding and interest in the local geology: John Rodgers, Yngvar Isachsen, and Rosemary Vidale. One of us (JMM) was supported by a NSF Science Faculty Fellowship during the summer of 1971.
* In large part reprinted from NEIGC Guidebook, 67th Annual Meeting, 1975, with permission of editors.
Summary
Although important unresolved problems remain in the Amenia-Pawling Valley, we are able to conclude with reasonable certainty that the valley is underlain by the overturned, eastern limb of a large NNE trending syncline. In the western limb of this fold the carbonate shelf remains hidden beneath Walloomsac and Everett schists. This structure is termed the Harlem Valley Syncline and is thought to be complementary to the Housatonic Highland massif and its southern extension. It is suggested that the Proterozoic gneisses at Corbin Hill are a relict klippen of a hard-rock thrust slice emplaced in the late Taconian Orogeny (Hudson Valley phase). Local allochthons of Everett Schist were emplaced at the sane time. Penetrative cleavage and metamorphism followed these events, probably, in late Ordovician time. A Devonian overprinting of Ordovician metamorphism is probable.

>C7: STRATIGRAPHY AND STRUCTURAL GEOLOGY IN THE HARLEM VALLEY, S.E. DUTCHESS COUNTY, NEW YORK
James M. McLelland
Donald W. Fisher
New York Geological Survey
The purpose of this field trip is to provide familiarity with the stratigraphy and structure of the Amenia-Pawling portion of the Harlem Valley in eastern New York State. Emphasis is placed upon stratigraphic relations of the Wappinger Group (Dana, 1879) which represent the Cambrian-Ordovician carbonate shelf sequence in this portion of the Appalachians. Additional stops will be made to examine the Poughquag Quartzite, the Walloomsac Schist, the Everett Schist, and Precambrian units of the Hudson Highlands, all of which are integrally related to the regional geology.
It should be understood that the structural framework and geologic history of this area have not been clearly deciphered. As in other parts of the Taconide Zone (Zen, 1972), complex polyphase deformation, regional metamorphism, and limited exposure have combined to leave scanty evidence of a protracted geologic history. A great deal more detailed work is required before the Harlem Valley area is well understood. It is our hope that this trip may arouse sufficient interest in the regional geology so that others will decide to undertake further field studies in the area.
Acknowledgments
We thank the following individuals for their roles in enhancing our understanding and interest in the local geology: John Rodgers, Yngvar Isachsen, and Rosemary Vidale. One of us (JMM) was supported by a NSF Science Faculty Fellowship during the summer of 1971.
* In large part reprinted from NEIGC Guidebook, 67th Annual Meeting, 1975, with permission of editors.
Summary
Although important unresolved problems remain in the Amenia-Pawling Valley, we are able to conclude with reasonable certainty that the valley is underlain by the overturned, eastern limb of a large NNE trending syncline. In the western limb of this fold the carbonate shelf remains hidden beneath Walloomsac and Everett schists. This structure is termed the Harlem Valley Syncline and is thought to be complementary to the Housatonic Highland massif and its southern extension. It is suggested that the Proterozoic gneisses at Corbin Hill are a relict klippen of a hard-rock thrust slice emplaced in the late Taconian Orogeny (Hudson Valley phase). Local allochthons of Everett Schist were emplaced at the sane time. Penetrative cleavage and metamorphism followed these events, probably, in late Ordovician time. A Devonian overprinting of Ordovician metamorphism is probable.

STOP 1. Roadcuts in Walloomsac and Wappinger
Roadcuts in Walloomsac schist and Wappinger carbonates on both sides of NY 22.
Here the Walloomsac schist overlies calcitic and dolomitic limestones of the upper Wappinger -- possibly the Copake Limestone. The presence of brown and tan weathering dolostone beds in the carbonates preclude their being Balmville. Probably this was a site of non-deposition of the Balmville. At or near the contact, there is developed tectonic interleaving of schist and carbonate. This interleaving could result from at least two causes: (1) differing mechanical properties of the schists relative to the carbonates; (2) the shearing off of original irregularities along the old erosional surface. Within the outcrop, the foliation and bedding surfaces strike N40E and dip 50°W. The stratigraphy is right side up. Tight folding takes place about N10-15E axes and the folds verge westward. Near the south end of the outcrop there exist good examples of the relationship of fold wavelength to bed thickness. Note that the principle foliation has been refolded representing, probably, the D2 and D3 events. A thin section of Walloomsac from this outcrop shows abundant quartz and biotite as well as garnet, feldspar, muscovite, graphite, and metallic opaques. Two generations of biotite can be seen megascopically.

STOP 2. Large roadcuts in upper Wappinger carbonates.
Nellie Hill. The beds strike N10-20E and dip 30°-40°E. In the fields beyond the west side of the road are outcrops of Balmville Limestone and Walloomsac Schist that also dip to the east. If one proceeds eastward over the top of the roadcut and onto the next ridge (-300 m), Briarcliff Dolostone is encountered. Still further to the east the Pine Plains Formation, Stissing Dolostone, and Poughquag Quartzite crop out successively until the proterozoic gneisses of the Housatonic Highlands rise in the ridge defining East Mt. Except for minor folding, the strata dip consistently to the east and the entire section must be regarded as overturned. Chestnut Ridge, immediately to the west on Rt. 22, consists of Everett Schist and is regarded as an allochthonous hard-rock slice.
The southern portion of the outcrop is thought to consist of Copake Limestone that has been pervasively folded about N10-20E axes, plunging l0°-l5°N. Excellent examples of transposed bedding and thinned out fold limbs can be seen. The rock consists of dark, pure calcitic metacarbonate interbedded with coarser sandy dolostone. Possible crossbedding can be seen in the steep walls of the roadcut.
At its northern end, the outcrop shows the development of well layered buff and brown dolostone beds interlayered with dark, massive calcite rich beds. These units are thought to belong to the upper portion of the Rochdale Limestone. Bedding averages around 0.5-1 m in thickness. Some of the dolostone beds are quartzose and show thin bedding laminations. No cross-bedding or graded bedding has been recognized and discoveries of the same will be welcomed.
Above the road level, and within the tree cover, there are developed coarse, gray, massive limestones that extend to the top of the hill. These are considered to be part of the Rochdale. Between the hilltop and the Briarcliff dolostone, limestone bearing units of possible Halcyon Lake assignation crop out. A problem with the correlations as given above is that the resulting thickness of the Rochdale Limestone is less than would be expected. Warthin (pers. comm.) reports approximately 125 m of Rochdale near Poughkeepsie. If the Halcyon Lake is present in the section above the Briarcliff here, it does not appear possible to have 125 m of Rochdale. Perhaps faulting has cut out some of the section. Alternatively the Halcyon Lake Fm. may not have been deposited locally. A further possibility is that the beds assigned here to the upper Briarcliff are actually Halcyon Lake.

STOP 3. Excellent outcrops of Everett Schist
Park on east side of NY 22 near bend in road. Walk southward along railroad tracks, for approximately 150 meters. Excellent outcrops of Everett Schist are exposed in a small railroad cut. NO HAMMERS PLEASE. Large (1/8" -1/4") staurolite and garnet crystals are developed in coarsely micaceous muscovite schists which display the typical silver sheen of the Everett at this grade. Quartz and feldspar are plentiful with quartz predominating. Some graphite is present. The foliation has been refolded.

Briarcliff Dolostone on east side of road.

Briarcliff Dolostone on hill to west of road.

Briarcliff Dolostone in roadcut.

Abandoned quarry in Briarcliff Dolostone to south of road.

Cut in Briarcliff Dolostone.

Cut in Pine Plains Formation.

STOP 4. Peckham Industries Quarry
The quarry is within Stissing Dolostone and the broad expanse of dazzling white dolostone reflects the purity of this lowermost carbonate. During World War II, this quarry was utilized as a source for magnesium. Within most units the rock consists almost entirely of dolomite and calcite. The structure within the quarry seems to be fairly straightforward. Bedding dips steeply around an anticline that trends N10-20E and plunges 10°-15°S. The core of this anticline is preserved in the lower quarry level where pelitic beds of Stissing are also exposed. Presumably these are related to the red shale horizons recognizedby Mrs. Knopf (1946) near the middle of the Stissing. At the stratigraphic level of the pelite rich zones, the Stissing is difficult to distinguish from portions of the Pine Plains Formation.
At the south end of the quarry beds of Pine Plains dolostones overly the Stissing. The Pine Plains appears to overly the Stissing around the entire margin of the quarry, reflecting its overall anticlinal structure. Because its regional extent is unknown, the Pine Plains in this area has been mapped in Undivided Carbonates (Of) in fig. 2.
In terms of regional structure, note that the quarry lies within the Wingdale-Bulls Bridge gap. Within this gap the Stissing Dolostone appears to wrap around the southern end of the Housatonic Highlands. Moreover, Stissing within the gap appears to be structurally and stratigraphically continuous with Stissing to the west in the Harlem Valley. This strongly suggests that the gap represents the south plunging nose, and upper limb, of the westward verging anticlinorium cored by the Proterozoic gneisses of the Housatonic Highlands. The possibility exists that this anticlinorium is developed on an eastward dipping thrust plate (Harwood and Zeitz, 1974).

Pine Plains Formation on west side of Rt. 22

Pine Plains Formation on east side of Rt. 22.

Manhattan Formation
Manhattan Formation of the schist mass comprising the east side of the valley.

Pine Plains Formation on west side of Rt. 22.

Stissing Dolostone on both sides of Rt. 22.

STOP 5. Corbin Hill
The long roadcuts on either side of NY 22 are fine examples of Pine Plains Formation. However we will not examine these at this location. The primary purpose of this stop is to point out, and discuss Corbin Hill which rises from the swampy fields to the west of NY 22.
Corbin Hill consists of Proterozoic (Helikian) gneisses whose bedding and foliation are conformable to the valley trends. These gneisses are surrounded by, and may rest on top of, interlayered Balmville limestones and Walloomsac slates. Balk, 1936, considered Corbin Hill to represent a slice of basement brought to its present erosional level along a steeply dipping reverse fault block that involved Precambrian rocks only (fig. 5a). If this mechanism is correct, then it should be reflected by a break in the stratigraphic succession of the valley carbonates. Similarly, if Corbin Hill punched its way upward as an elongate domal mass, then the carbonate stratigraphy should wrap around the Precambrian gneisses (fig. 5c).
Mapping around Corbin Hill has shown that the carbonate stratigraphy is unaffected by the gneiss body. Units of the Wappinger Group can be followed down the valley and "through" Corbin Hill with no signs of displacement or "wrapping-around". As shown in fig. 2, the Briarcliff Dolostone is the Wappinger unit underlying Corbin Hill. This is inconsistent with an up punched or up thrust origin of this feature. Similarly the presence of Balmville limestone, Walloomsac Schist, and even Everett Schist in close proximity to the western margin of the Precambrian gneisses makes it difficult to account for Corbin Hill by essentially autochthonous mechanisms. The stratigraphic continuity of the carbonate shelf units, and their overturned attitudes, cannot tolerate vertical movement models for Corbin Hill. In effect, the gneisses on Corbin Hill do not appear to be rooted through the valley carbonates. While this conclusion cannot be made firm without further evidence it does represent our preferred interpretation of the field data.
In the absence of further data, we are unable to offer any convincing, detailed history relating to the origin of Corbin Hill. Our preferred model is that these gneisses represent an erosional outlier of a low dipping hard-rock slice that transported Proterozoic rocks from east to west. Rather than suppose the existence of extensive Proterozoic rocks in this slice (fig. 5d), we prefer to attribute the rocks of Corbin Hill to tectonic slivering of basement rock by an overriding slice of Everett Schist (fig. 5e). This slivering could have occurred in the basement rocks that underly the Manhattan Schist terrain, forming the ridge on the east side of the valley. While other source areas exist, this one appears to be the most economical of long distance transport. Similarly, slivering of the Proterozoic offers the simplest explanation for the restricted outcrop of Corbin Hill.
The foregoing model is consistent with the recent aeromagnetic interpretations of Harwood and Zeitz (1974) for rocks of the Housatonic massif. Here, eastern, weakly magnetic Precambrian rocks are thrust westward along low angle faults rooting in the east. This thrusting occurred late in the Taconian Orogeny and involved the various hard-rock slices of the High Taconics and the Precambrian massifs. Note that just to the north of Towners, New York, Balk (1936) mapped Precambrian and Poughquag Quartzite thrust over carbonate units. Lying north of this is the small Pine Island mass of Precambrian and Poughquag which, presumably, is also thrust in (see STOP 9).

Pine Plains Formation on east side of NY 22.

Briarcliff Dolostone on east side of NY 22.

Briarcliff Dolostone in large roadcut on east side of NY 22.
Abundant diopside and tremolite are developed in the outcrop.

Briarcliff Dolostone on west side of NY 22.

STOP 6. Road cut in the Pine Plains Formation.
Excellent example of the highly variable lithologies that characterize this unit. Brown and buff sandy dolostones alternate with quartzites and relatively pure, massive white dolostones. Tan colored units often shows typical rotten weathering. Punky, asphalt bearing layers give off H2S upon breaking open. Bedding is of variable thickness. The beds of quartzite and chert have undergone boudinage and pinch and swell of textbook quality. Reaction rims and selvages exist between the carbonates and the quartz rich layers. In the brown to purplish pelitic zones phlogopite, sphene, diopsidic pyroxene, and tremolite are developed. Within the more massive beds of grey weathering, white colored dolostones diopside tablets attain dimensions approaching 3 cm across.
On the east side of NY 22, the Pine Plains units strike subparallel to the road and dip steeply to the east. On the west side the strike has turned E-W and dips are steeply to the south. This represents a fairly open, dextral type of fold that swings the carbonate units and the Manhattan Schist westward for about 0.8 km at which point strikes return to NNE trends (see fig. 3).
The contact between the Briarcliff dolostones and the Pine Plains Formation is thought to occur just to the west of NY 22. The low hill rising from NY 22 is known to be underlain by Briarcliff Dolostone and this unit is beautifully developed just to the south of the NY 55 underpass (0.5 km along strike to the north). Perhaps some of the massive, pure dolostone at the north end of the cut should be assigned to the Briarcliff.
Minor folds in the outcrop suggest that we may be observing here the limbs of larger isoclinal folds. Two foliations exist and are best manifested by micaceous bands.

Briarcliff Dolostone
Briarcliff Dolostone with excellent diopside crystals on north side of NY 55.

STOP 7. Very large roadcuts in the Briarcliff Dolostone.
The Briarcliff consists typically of grey weathering, light colored rather pure dolostones with yellow to white and even black chert layers (1"-2") abundantly developed in some units. Knots and nodules of vitreous quartz are locally present and weather out above the dolostone surface. At the east end of the cut some dirty portions of the Briarcliff exhibit moderate development of phlogopite. At the western end of the beds of dolostone are massive and pure. This difference appears to be reflected in the more open style of folding associated with the pure thick layered (5-7 m) beds.
A large number of different structural styles and phenomena can be seen in the roadcut. Folds range from fairly open flexural styles to isoclinal folds that may involve flowage and/or significant flattening. In many areas of the cut disharmonic folding is pronounced with the dolostones undergoing extensive flowage while the much more brittle chert layers show rupturing and extensive separation of blocks. Examples of the folded boudinage are beautifully developed at the eastern end of the roadcut.
There appear to be at least four major compressional events recorded in the outcrop. The earliest of these is manifested by only an early foliation (flakes of phlogopite) that lies within the surfaces rotated by the earliest recognizable folds. These folds are generally very tight to isoclinal and their axial planes display a variable attitude. In general the axes of these folds do not plunge steeply but exceptions are common due to later refolding. These tight folds are then refolded about NNE axes with relatively steep plunges (50-60°). This leads to an interesting set of geometrical relationships wherein the early isoclinal folds are well exposed in vertical faces of the cut while the steeply plunging folds are best seen on horizontal erosional surfaces. A final set of upright, open, and gently plunging folds that trend approximately N-S. These are best exposed near either end of the large road cut.
Fold interference patterns are best seen at three places. The first is on the north side of the road and near the east end of the roadcut just prior to the beginning of the cut is really steep faces. Here upright isoclinal folds are clearly refolded by steeply plunging, tight folds. Close examination of the folded surfaces of the isoclinal folds indicates phlogopite mica growing parallel to them. Folded boudinage also appears to be present.
A second vantage point for observing fold interference is on the north side of the cut just beyond the large saddle nearly 2/3 of the way up the cut. Here several pelitic layers define the core region of early gently plunging isoclinal folds. These can be clearly seen to be folded by a later, steeply plunging fold set.
A third example of fold interference lies on the south side of the cut almost directly opposite the case cited immediately above.
Numerous high angle faults cause observable offsets in the dolostones. Some of the fault stones contain serpentine. These faults appear related to a larger fault zone that causes a topographic saddle about half way along the roadcut.
Of particular petrologic interest are layers of tremolite and diopside in the Briarcliff. These are best observed on the top of the roadcut at its southeastern end. Massive beds of tremolite and diopside areas are mutually exclusive and seem to reflect the relative immobility of the vapor phase during metamorphism. Note that the diopsides, especially, appear to post-date any severe orogenic events.

Calcitic Walloomsac schists
Calcitic Walloomsac schists containing calc-silicates, calcite, and overlain by a calc-silicate bearing calcitic dolostone. The latter may be a tectonic sliver similar to those seen at Stop 1.

STOP 8. Balmville / Walloomsac contact
In this small roadcut we are afforded a view of the contact between the Balmville Limestone and the Walloomsac Schists. At the north end of the outcrop the schists overly the Balmville, but at the south end, units dip steeply to the east, and, if outcrop were preserved, the Balmville would overly the schists. We consider this relationship to be due to proximity to the hinge line of the overturned Harlem Valley Syncline whose upright, western limb is entered as NY 55 is followed to the west (see fig. 3). The roadcut itself probably represents a minor fold near the hinge line since black Walloomsac calcitic schists are found farther to the east at mileage 26.8.

STOP 9. Thrust contact
Thrust contact between the Proterozoic gneiss and the Cambrian-Ordovician shelf sequence. Balk (1936) mapped the Towners Thrust through this area. As he indicated, the upper thrust plate consists of Proterozoic gneisses overlying Poughquag quartzites. Beneath the Poughquag there appears a much deformed and cleaved impure dolostone. Because of the impurity of this unit (particularly the number of chert stringers in it), we have tentatively correlated these dolostones with the Briarcliff. The possibility remains that future work will result in a revision of this correlation and the dolostones may be incorporated into a dirty, lower facies of the Stissing. At this grade of metamorphism, and with lack of fossil control, it is difficult to make stratigraphic assignments with absolute certainty. However, the present correlation is preferred.
If the dolostones at this stop are accepted as Briarcliff, then the stratigraphy itself necessitates a reverse fault between the Proterozoic/Poughquag and the underlying Briarcliff. Such stratigraphic control would demonstrate thrusting, and fix its minimum displacement. However, this control is not necessary in order to demonstrate that low angle faulting was extremely likely in this area. Balk (1936) concluded that fabrics and minor structures in the surrounding rocks strongly suggested a reverse fault at the Proterozoic/Poughquag contact with the carbonates. Examination of the Proterozoic gneisses shows the presence of strong mineral lineations, rodding, and grooving near their lower contact. An anastomosing network of foliation planes can be seen intersecting an earlier foliation. The later foliation is oriented approximately parallel to the postulated plane of faulting and is believed to be similar to the mylonites observed by Ratcliffe (1975) and Harwood (1975) in thrust slices of the Berkshire massif. The linear features developed on these foliation planes are thought to manifest the slip direction along the fault. Pronounced grooving in the Poughquag quartzite is attributed to the same tectonic event. These lineations trend E-W and plunge to the east at about 40°. Within most of the Harlem Valley lineations vary around NNE and NNW directions parallel to the major fold axes. The high angle between the lineations here and both regional and local fold axes strongly suggests that the linear features are a result of fault motion and probably lie parallel to the slip vectors along these faults (i.e. an "a" lineation).
At the Proterozoic-Poughquag contact there are developed biotite rich seams that resemble the blastomylonites of the Berkshires (Ratcliffe, 1975; Harwood, 1975).
A short distance up the hillside to the southeast there is exposed a vertical face of Proterozoic granitic gneiss. The foliation in this rock has been tightly refolded about gently dipping axial planes, many of which have been infilled by quartzo-feldspathic material. These axial planes dip parallel to the presumed thrust fault. The lower limb of several of the folds have been attenuated. A general East over West movement is indicated. As with the linear features and mylonites, these folds and granitic seams are reminiscent of minor structures of the Berkshires. We believe that the minor folding and associated axial plane foliation in these rocks are the consequence of westward thrusting of the Proterozoic, with local patches of attached Poughquag quartzite, over the Cambrian-Ordovician carbonates.
As shown on fig. 6 the Towners Thrust extends well beyond its exposure at Stop 10. Following Balk (1936), we conclude that it is likely that Pine Island is part of the thrust plate and this hypothesis has been incorporated into fig. 6. The eastern margin of the thrust plate cannot be drawn in with any certainty, and we have not attempted to extrapolate beyond Pine Island.
The full extent of the Towners Thrust is presently unknown. It may continue southward into the pronounced N-S valley within the Proterozoic. In this case the small outcrops of Wappinger carbonates in this valley may represent tectonic slivers along the sole of the thrust. Alternatively the trace of the thrust may pass along the Proterozoic-Paleozoic contact west of Towners (fig. 6), and then swing to the south at the western margin of this Proterozoic block. This is essentially the pattern shown on the 1973 edition of the New York State Geological map. Such a trace would explain the abrupt truncation of the carbonate shelf sequence by the Proterozoic just to the west of Towners. It would also explain the fact that, along its western contact, this mass of Proterozoic appears to overly shelf carbonates. A third possibility is that the abrupt termination of the Paleozoic stratigraphy west of Towners is due to a WNW high angle fault that connects the thrust at Cornwall Hill with its continuation along the N-S Proterozoic-Paleozoic contact west of Towners. In this case the small carbonate bodies referred to above as possible tectonic slivers might possibly lie within erosional windows through the overlying Proterozoic thrust sheet.
The regional extrapolation of the Towners Thrust remains a major research problem in the area. Together with Corbin Hill, it raises the possibility that portions of the Hudson Highlands may be parautochthonous, as in the Berkshires, or even allochthonous, as suggested by Isachsen (1964).

GUIDEBOOK to FIELD EXCURSIONS
conducted at the
49th ANNUAL MEETING
of the NEW YORK STATE GEOLOGICAL ASSOCIATION (September, 1977)
Philo C. Wilson. Editor
Host: Earth Science Department, State University College at Oneonta, N.Y.
Additional copies of this guidebook may be purchased from the secretary of the New York State Geological Association:
Dr. Daniel F. Merriam, Department of Geology, Syracuse University, Syracuse, N.Y. 13210
or from the editor.
DEDICATION
This Field Guidebook is affectionately dedicated to
All Students of Geology: past, present, and future, from pebble pups to polished professionals; for it is their interest, enthusiasm, insights, and progress that make conferences and guidebooks such as this worthwhile.
ACKNOWLEDGEMENTS
Without the time, effort, dedication, and professionalism of a number of individuals, neither the meeting nor the Guidebook would have been possible.
The responsibility tor the planning, organization, and arrangements tor both the meeting and the field trips fell on the shoulders of this year's president, Dr. P. Jay Fleisher. To a large extent, any successes enjoyed by either ventures are due to his efforts.
The contributing authors and field trip leaders (in most cases, the same individuals) are owed a huge debt of gratitude by both the current membership of the association and future users of the Guidebook. Without their generous donation of time and expertise, the heart of the meeting and this lasting record of its more important proceedings would be missing.
Behind the scenes, others have made significant contributions. We are indebted to the college tor providing its facilities for the smoker and banquet. The editor is especially grateful to Ron Embling in the college's IRC department tor extensive expert advice on the illustrations and for careful preparation of the quality metal plates used to print some of them; to Charles Winters for much of the photographic work; and to Joanne Ruteshouser for some of the redrafting required. Our heartfelt thanks go also to Moira Greiner who really put this finished product together by typing the introductory portions; snipping, pasting, composing, and retyping portions of the text; and providing the pagination as the final touch to each manuscript. Finally, we are all grateful to Jim Sheff in the College Print Shop who ran off the Guidebook copies, to the college, again, for allowing us to use their printing facilities - thereby greatly reducing the Guidebook costs, and to the student help who will be returning from summer vacations to assist in the arduous collating and binding processes ... even though they don't know it as of this writing.

A1: CARBONATE AND TERRIGENOUS SEDIMENTARY FACIES OF TIDAL ORIGIN, EASTERN NEW YORK
Gerald M. Friedman
R. P. I.
This is a field trip to study sedimentary facies of tidal origin. At each exposure we shall study the rocks in terms of lithology, geometry, sedimentary structures, and fossils and concentrate on the pattern of deposition which created the facies. In this kind of approach the name and age of the formation becomes secondary; hence this field trip has been designed irreverently; it pays no heed to formation boundaries. Facies analysis will proceed within the boundary conditions of each single exposure.
During Cambrian to Lower Ordovician time, most of the North American continent was a shallow epeiric carbonate shelf, like the present-day Bahama Bank. At the eastern margin of this shelf, i.e. at the eastern margin of this continent, a relatively steep slope existed down which carbonate sediment moved by slides, slumps, turbidity current, mud flows, and sand falls to oceanic depths (Sanders and Friedman, 1967, p. 240-248; Friedman, 1972). We shall visit shallow-water carbonates shelf deposits which accumulated 30 to 40 miles west of the steep paleoslope which existed during Cambrian to Lower Ordovician times. These shallow-water epeiric carbonate sediments, located in such close proximity to a major ocean, were under the effects of tidal currents. On this field trip we shall examine products of tidal sedimentation on this Cambrian to Lower Ordovician carbonate shelf. For details on the stratigraphy of these carbonate deposits reference should be made to Fisher (1954, 1965) and Braun and Friedman (1969), and on the depositional environments to Braun and Friedman (1969), Friedman (1972), Buyce and Friedman (1975), and Friedman and Braun (1975), and Mazzullo and Friedman (1975. 1977).
Coincident with and after the Acadian orogeny during Middle and Late Devonian times huge river systems of a "tectonic delta complex" (Friedman and Johnson, 1966) drained the area which is now the site of the Catskill Mountains. Devonian rocks, of braided and meandering stream origin, inter-finger with those of tidal, nearshore and offshore origin. We shall examine the tidal deposits, all of which are terrigenous. For details on the stratigraphy and depositional environments of the rocks of the tectonic delta complex reference should be to Johnson and Friedman (1969); some reinterpretations have been offered by Friedman (1972).
ITINERARY
Each stop describes and interprets the sedimentary facies; hence each stop should be regarded as self contained. Figure 1 is the road log and shows the location of all the six stops visited

STOP 1. FORT HUNTER QUARRY. Products of Tidal Environment: Flat Algal Mats
STOP 1. FORT HUNTER QUARRY. Products of Tidal Environment: Flat Algal Mats Alight at slight bend in road and walk to Fort Hunter Quarry which is across railroad track close to Mohawk River. (Fort Hunter Quarry cannot be seen from road; another small quarry visible from road is approximately 0.1 mile farther east, but will not be visited on this trip).
Stromatolites in the Fort Hunter Quarry consist almost entirely of dolomite and feldspar in the form of irregularly bedded, finely-laminated, undulating structures. The rocks in this quarry are part of the Tribes Hill Formation of earliest Ordovician age (Fisher, 1954). The lithofacies of the Tribes Hill Formation have been studied in detail by Braun and Friedman (1969) within the stratigraphic framework established by Fisher (1954). Figure 2 is a columnar section showing the relationship of ten lithofacies to four members of the Tribes Hill formation. At Fort Hunter we will study the lowermost two lithofacies of the Fort Johnson Member (see column at right [east] end of section, in fig. 2).
Two lithofacies are observed: (1) lithofacies 1, mottled feldspathic dolomite, and (2) lithofacies 2, laminated feldspathic dolomite. Lithofacies 1 is at the bottom of the quarry, and lithofacies 2 is approximately half way up.
Lithofacies 1. This facies occurs as thin dolostone beds, 2 cm to 25 cm but locally more than 50 cm thick, with a few thin interbeds of black argillaceous dolostone which are up to 5 cm thick. In the field, the dolomite shows gray-black mottling and in places birdseye structures. In one sample, the infilling of the birds-eyes shows a black bituminous rim which may be anthraxolite. In the field, trace fossils are abundant, but fossils were not noted. Authigenic alkali feldspar (microcline) is ubiquitous throughout this lithofacies; its identity as alkali feldspar was determined by x-ray analysis and staining of a thin section with sodium cobaltinitrite. The insoluble residue makes up 22 to 54% by weight of the sediment in samples studied with most of the residue composed of authigenic feldspar.
Lithofacies 2. This lithofacies is mineralogically identical to the previous facies but differs from it texturally and structurally in being irregularly bedded and in containing abundant undulating stromatolitic structures ("pseudo_ripples") as well as disturbed and discontinuous laminations. In places there are a few thin interbeds of black argillaceous dolostone. The thickness of the laminites of this facies ranges from 1/2 mm to 2 or 3 mm; on freshly broken surfaces the color of the thinner laminae is black and that of the thicker ones is gray. The insoluble residue, for the most part composed of authigenic feldspar, constitutes between 35% and 67% by weight in samples studied.
These two lithofacies which form the basal unit of the Ordovician, were formed on a broad shallow shelf. Stromatolites, birdseye structures, scarcity of fossils, bituminous material, syngenetic dolomite, authigenic feldspar, and mottling suggest that these rocks were deposited in a tidal environment (Friedman, 1969). Based on analogy with the carbonate sediments in the modern Bahamas, Braun and Friedman (1969) concluded that these two lithofacies formed under supratidal conditions. However in the Persian Gulf flat algal mats prefer the uppermost intertidal environment, and along the Red Sea coast they flourish where entirely immersed in seawater, provided hypersaline conditions keep away burrowers and grazers (Friedman and others, 1973). Hence on this field trip we may conclude that the stromatolites indicate tidal conditions without distinguishing between intertidal and supratidal. For more details on these lithofacies refer to Braun and Friedman (1969).

Cross original Erie Canal, built in 1822.
Cross original Erie Canal, built in 1822. Amos Eaton surveyed this route at the request of Stephen Van Rensselaer; after this survey Amos Eaton and Van Rensselaer decided to found a school for surveying, geological and agricultural training which became Rensselaer Polytechnic Institute.

STOP 2. NORTH TRIBES HILL QUARRY Products of Tidal Channels
Route of Walk. Take the trail towards old abandoned crusher, but instead of heading towards the quarry move uphill to the first rock exposures. The rocks to be examined are near the edge of steep cliff.
Description and discussion. In the rocks at this exposure the field relationships show typical channels truncated at their bases. Lodged within the channels are limestone blocks of variable shape ranging in diameter from about one to three feet (fig. 3). These blocks resemble similar blocks in tidal channels of the Bahamas which are derived by undercutting of the banks of the tidal channels. The blocks at this exposure are rounded, suggesting that they have undergone some transport.
The rocks composing the channel (i.e. the channel fill) and the blocks of rock within the channels have been described as lithofacies 8 (channel fill) and lithofacies 7 (blocks) of the Wolf Hollow Member of the Tribes Hill Formation (lowermost Ordovician) (see columnar section of fig. 2; column at the right end of the section) (Braun and Friedman, 1969). The channel fill (lithofacies 8) consists of intrasparite and biointrasparite with sporadic ooids, a high-energy facies, whereas the blocks (lithofacies 7) consist of mottled dolomitic micrite and biomicrite, a low-energy facies of the undercut bank. The micrite blocks which foundered in the channels must have been indurated penecontemporaneously.
Hence during earliest Ordovician time high-energy tidal channels crisscrossed tidal flats at this site. In them water coming from the deep ocean to the east rose and fell with the changing tides.

STOP 3. Lester Park
PRODUCTS OF INTERTIDAL ENVIRONMENT: DOMED ALGAL MATS (CABBAGE HEADS)
This locality is the site of one of the finest domed algal mats to be seen anywhere preserved in ancient rocks. On the east side of the road in Lester Park a glaciated surface exposes horizontal sections of the cabbage-shaped heads composed of vertically stacked, hemispherical algal layers. These structures, known as Cryptozoons, have been classically described by James Hall (1847,1883), Cushing and Ruedemann (1914), and Goldring (1938); an even earlier study drew attention to the presence of ooids as the first reported ooid occurrence in North America (Steele, 1825). Interest in these rocks has been revived as they are useful environmental indicators (Logan, 1961; Fisher, 1965; Halley, 1971; Owen, 1973). The algal heads are composed of discrete club-shaped or columnar structures built of hemispheroidal algal mats expanding upward from a base, although continued expansion may result in the fusion of neighboring colonies into a Collenia-type structure (Logan, Rezak and Ginsburg, 1964) . The algal mats are part of the Hoyt Limestone of Late Cambrian (Trempealeauan) age. Their intertidal origin has been inferred by (1) observations in the rocks, and (2) by analogy with similar modern algal heads.
The evidence for deposition under tidal conditions for the Hoyt Limestone at Lester Park includes: (1) mud cracks, (2) flat pebble conglomerate, (3) small channels, (4) cross-beds, (5) birdseye structures, (6) syngenetic dolomite, and (7) stromatolites (for criteria on recognition of tidal limestones, see Friedman, 1969). The analogy with modern environments relates to the occurrence of cabbage-shaped algal heads in the intertidal zone of Shark Bay, western Australia, in which the height of the domes is controlled by the degree of turbulence (Logan, Rezak and Ginsburg, 1964; Hoffman, Logan and Gebelein, 1969). With increasing wave and current energy the height of the domes increases; the relief of the domes decreases landward towards quieter water conditions.
At Lester Park the heads which are circular in horizontal section range in diameter from one inch to three feet, many are compound heads. The size of the larger heads suggests that they formed in highly turbulent waters.
The line of depositional strike along which the domed algal mats occur was probably where the waves were breaking as they came across the deeper ocean from the east and impinged on the shallow shelf.
Several petrographic observations in these rocks permit an analogy with modern algal mats in hypersaline pools of the Red Sea Coast (Friedman and others, 1973). Mat-forming algae precipitate radial ooids, oncolites, and grapestones which occur in these rocks; interlaminated calcite and dolomite which in part compose the stromatolites of the Hoyt Limestone correspond to alternating aragonite and high-magnesian calcite laminites which modern blue-green algae precipitate. In modern algal mats the high-magnesium calcite laminites contain abundant organic matter in which magnesium has been concentrated to form a magnesium-organic complex. Between the magnesium concentration of the high-magnesium calcite and that of the organic matter sufficient magnesium exists in modern algal laminites to form dolomite. Hence the observation in ancient algal mats, such as observed in the Hoyt Limestone, that calcite and dolomite are inter-laminated, with calcite probably forming at the expense of aragonite and dolomite forming from high-magnesium calcite.

STOP 4. GILBOA FOREST Tidal Marsh Facies
No examples of this tidal marsh facies have been found in situ. However giant seed ferns of the Gilboa Forest (Goldring, 1924, 1927), which grew in a marsh environment, were discovered in the now inactive Riverside Quarry near here (Fig. 4). More than 200 stumps were taken from this single quarry; some of these have been placed at this site, others are now preserved in museums (New York State Museum, Albany; Geological Museum, Rensselaer Polytechnic Institute). The "trees" of Gilboa Forest are among the world's oldest; they grew in a tidal marsh environment of the Catskill Deltaic Complex. The bulbous bases of these fossils were found in place in dark-colored shale; the upright trunks were encased in olive-gray, cross-bedded sandstone of probably tidal origin. The age of the "trees" is latest Middle Devonian.

STOP 5. GRAND GORGE SECTION Intertidal Facies: Tidal Flats and Tidal Channels Channels
The rocks at this exposure are medium gray, fine-grained graywackes; tabular cross-beds are ubiquitous; parting lineations are common. The most interesting single feature at this exposure are the tidal channels (Fig. 5). These channels are small, about 2 to 10 feet in cross section; they truncate the underlying strata. The channel fill consists mostly of a lag concentrate of transported spiriferid brachiopod shells. Usually the shell material is abundant enough to rate for the channel the name "coquinite." Holes in the coquinites are molds of brachiopods. Interestingly, brachiopod shells are confined only to the coquinite lenses; they are not found in the surrounding rock. Hence the brachiopods were treated by the channels as pebbles that were washed in from the open marine environment. In analogous modern tidal channels typical open sea species are washed into the channels by flood tides (Van Straaten, 1956).
Note that the next exposure south (uphill) is composed of red fluvial rocks.
This exposure has been described by Johnson and Friedman as part of their section 43 (1969. p. 471-415, especially figs. 22 and 23). These rocks are the clastic correlatives of the Tully Limestone (early Late Devonian or latest Middle Devonian).

STOP 6. EXPOSURE ON EAST SIDE OF ROAD Deposits of Tidal Deltas and Lagoons
At this exposure lenticular sandstone bodies inter-finger with dark-gray siltstones and shales (Fig. 6). The sandstones have a vertically shingled, or en echelon, configuration relative to one another. Even the thickest sandstone, approximately 6 feet thick, thins and pinches out laterally (see fig. 25, p. 478 in Johnson and Friedman, 1969). The sandstones contain marine fossils and wood fragments. In places they are crossbedded; ripple marks are locally present. In the siltstones and shales wood fragments are abundant. The presence of marine fossils, the absence of channels, and the lenticular geometric configuration of the sandstones within inter-fingering siltstones or shales suggests that the sandstones are probably the products of tidal deltas. If so, the siltstones or shales are of lagoonal origin.
The rocks at this exposure belong to the Hamilton Group (Middle Devonian) and are about 600 feet below the stratigraphic level of the Tully clastic correlatives.

A2: ICHNOFOSSILS OF THE TULLY CLASTIC CORRELATIVES IN EASTERN NEW YORK STATE
Molly Fritz Miller
Pomona College
&
Kenneth G. Johnson
Skidmore College
Within the clastic correlatives of the Tully Limestone in eastern New York State there occurs a remarkably complete spectrum of ancient sedimentary facies (Johnson and Friedman, 1969; Johnson, 1968, 1970, 1972, 1976). These beds, which evolved during a transgressive pulse in the building of the great Catskill deltaic system, are part of a 3000 meter (10,900') sequence that constitutes the standard for the Devonian System of North America (Figs. 1 and 2). They are exposed at the northeastern end of the Allegheny Synclinorium, are essentially undisturbed and, for the most part, very fossiliferous. Laterally transitional between those beds that are clearly of marine origin and those that are clearly non-marine are sandstones and shales that have sedimentary structures, lithology, geometric relationships with adjacent units and biogenic structures that indicate that they evolved in tidal and shallow sub-tidal environments.
The purpose of this field trip is to focus on one aspect of the evidence used to develop environmental assignments for the Tully clastic correlatives; namely, biogenic structures

ON LEFT Notice flat-topped crest of hills.
Streams are eroding into horizontally bedded rocks of Catskill lithofacies.

ON RIGHT Kame and kettle topography.

ON RIGHT Top of Grand Gorge
(Section 43 of Johnson, 1968). Exposure consists of alluvial channel sandstone resting on red overbank shale.

Top of tidal channel facies.

STOP 1. Cross-bedded sandstone of tidal channel facies
PARK on right side of road. Walk back to tidal channel outcrops. BE VERY CAREFUL. THIS IS A NARROW SPEEDWAY WITH POOR VISIBILITY.
Outcrop is cross-bedded sandstone of tidal channel facies with lag-concentrates of shallow marine spiriferid brachiopods.
Ichnofossils:
2nd exposure above base (begins approximately 50 feet above base of section): intermediate-sized (3-5 mm) specimens of Skolithos, large vertical cylindrical structures (rare, near top) molds of surface trails on undersides of beds.
3rd exposure above base: same Skolithos; also nondescript bioturbation, but this difficult to determine because of poor definition of lamination.
Upper section: abundant medium and small sized specimens Skolithos in siltstone float; Planolites also common. Well preserved specimens of Spirophyton are rare, but incomplete specimens are fairly common. Much of rock is highly bioturbated,

ON RIGHT, in distance - Large quarry
ON RIGHT, in distance - Large quarry from which much of stone for Gilboa Dam was taken. Completion of dam impounded waters of Schoharie Creek, forming Schoharie Reservoir; a part of New York City water supply system.

Gilboa Seed Ferns
On right - display of seed-fern stumps taken from quarry just to southwest. Some 200 specimens were found during the quarrying operation. These seed-ferns are thought to have grown to heights of some 60 feet in swamps along the seaward margin of the Catskill deltaic plain during late Medial Devonian time. They were buried during a minor oscillation of the marine shoreline in tidal channel or bar sand deposits.
2013: This display was moved across the river as excavation took place in 2010 -- OHM

STOP 2. Ledges on west bank of Schoharie Creek
Burrowed Hamilton Group sandstones.
Ichnofossils:
Lower part of section: Underneath re-entrant are specimens of Planolites, Isopodichnus; small paired burrows of Arenicolites can also be seen. Larger U-shaped burrows (Arenicolites) and Skolithos occur in overlying bed. Under a re-entrant on the upstream side of the outcrop is ? Teichichnus; other specimens occur at about this layer.
Upper bedding surfaces: 2 sizes Skolithos; sediment scoured from around larger burrows. Larger vertical burrows are common; horizontal burrows (Planolites) less so. Specimens of Arenicolites and Isopodichnus are rare.

ON RIGHT - Gilboa Dam.

ON LEFT - Gilboa Central School

STOP 3. Section 46 of Johnson, 1968
PARK ON RIGHT (at South end of bridge). Walk down path to mouth of Manor Kill
The beds exposed in the Manor Kill Gorge are within the upper part of the Hamilton Group. Those in the lower part of the section, adjacent to the Schoharie Reservoir, are trough cross-bedded, burrowed, medium-grained sandstone of the Chemung lithofacies assigned to the tidal channel facies. Some of these sandstones are rich in plant material and in a few places, during low water stages of the reservoir fossil seed-fern stumps, in growth position, may be seen. The remainder of the section upstream consists of interbedded red and green shales, dark gray shales and medium gray, shallowly cross-bedded, fine-grained sandstone; interpreted, respectively, as distal alluvial plain, tidal flat and tidal channel facies.
Ichnofossils:
Base (below spring water level): Ripple marked bed covered with small specimens of Skolithos, abundant Planolites and Skolithos in float .
(just above spring water level): Arenicolites, Skolithos, Planolites, Bifungites (rare) and Cruziana in blocks of float at water level.

STOP 4. Intake Building of Schoharie Reservoir
(Section 47 of Johnson, 1968).
PARK ON RIGHT. WALK DOWN ROAD to Intake Building
The lower 17' of section consists of dark gray siltstone and shale; above this is 114' of lighter gray, in part shallowly cross-bedded, fine-grained sandstone of tidal or very shallow sub-tidal origin.
Base: Abundant specimens of Spirophyton in ditch outcrop behind Intake Building; also some fine sandstone above this is highly bioturbated.
About 50' above base (at level of birch post): Cruziana (?) on underside of sandstone bed.
Middle: few layers with molds of surface trails exposed on undersides of beds up hill from road.

STOP 5 (Section 48 of Johnson, 1968)
At this point Bear Kill drops over Hardenburg Falls and flows into Schoharie Reservoir. Beds here are assigned to the tidal channel and tidal flat facies. The tidal channel facies is represented by gray, cross-bedded, fossiliferous sandstones and the tidal flat facies by very dark gray, very thin-bedded, in part conglomeratic, shales. Lag-concentrates in both facies are rich in shallow marine brachiopod shells.
Base: Rare Skolithos and Planolites; very rare large cylindrical burrows.
About 8' above base: Skolithos
Above falls: thin bedded siltstone with rare Planolites.

DEC Regional Headquarters.

ON LEFT - Outcrop of Catskill lithofacies

STOP 6. (Section 36 of Johnson, 1968)
Small house on left just below prominent sandstone ledge.
In roadside quarry, about 0.2 mile east of house, shales of offshore facies. Behind house are sandstones of probable bar origin.
Lower quarry: Several layers with interference ripple marks cut by Skolithos and Planolites with coarser burrow fill.
Section behind house: Abundant large Skolithos. Note that a few burrows intersect. Some of the burrow walls are clearly defined, others not. A few layers contain small sinuous specimens of Planolites as well. A poorly preserved specimen of Cruziana has also been found here. Burrows formed in the relatively coarse sand would have been more likely to collapse than those formed in more fine grained sediments.

Cross SUSQUEHANNA RIVER.

STOP 7. (Section 22 of Johnson. 1968)
Flow-rolls of Chemung lithofacies
This outcrop contains an example of the flow-rolls which are locally common in the Chemung lithofacies. These occur as beds of internally disturbed structure underlain and overlain by horizontal, well-bedded strata. Within the flow-roll beds are nodule-shaped, concentrically laminated masses of medium gray, very fine-grained sandstone enclosed in slightly darker colored siltstone. The laminar structure is due to concentric, extremely thin, dark laminae composed largely of very fine plant fragments. The enclosing siltstone commonly has a diapiric relationship to adjacent pillows. This outcrop is at the distal edge of the near-shore facies.
Base: Specimens of Skolithos and Planolites are present, but not common. They are most easily seen on shale partings. Note the absence of trace fossils near the flow structures.
About 10 feet above flow structures: Specimens of Skolithos and Planolites and molds of surface trails rare to common on shale partings.

STOP 8. Gilbert Lake State Park.
(Section 9094 of Thayer, 1972)
PARK ON RIGHT. WALK UP SERVICE ROAD TO ROCK QUARRY.
Although well above the Tully clastic correlatives, these fossiliferous, interbedded gray sandstones and shales exhibit typical characteristics of the eastern New York Chemung lithofacies.
Near base: Abundant specimens Zoophycos with diverse forms. It is recognizable in vertical section as a series of horizontally oriented chevrons. Specimens of Planolites and Skolithos are abundant; Cruziana, Bifungites, large horizontal burrows and Arenicolites are rare, but present. Note specimen of Arenicolites on vertical surface of piece of float about seven feet above quarry base.
Upper portion of quarry: Abundant specimens of Planolites, Skolithos and some of Zoophycos. Highly bioturbated sandstone is interbedded with laminated sandstone, implying influxes of sediment.

STOP 9. Roadside quarry
(Section 15 of Johnson, 1968) PARK ON SHOULDER AND WALK UP unsurfaced road to roadside quarry.
Beds exposed in this unnamed tributary of Stony Creek and adjacent abandoned quarry are assigned to the off-shore facies of the Tully clastic correlatives.
Base: Planolites - rare to common; Skolithos common to abundant in siltstone; Bifungites rare. Zoophycos absent.
In stream bed: Abundant float (fine to very fine sandstone) with abundant Zoophycos. Note diversity of shapes - from nearly elliptical to strongly lobate. Specimens Planolites and Skolithos are also common, as large horizontal burrows. Zoophycos rarely occurs on same slab with other trace fossils.

Chemung lithofacies flagstone.
Bank on left and Morris Inn on right constructed of Chemung lithofacies flagstone.

ON LEFT - quarry in Chemung lithofacies.

STOP 10. Offshore facies
(Section 9063 of Thayer, 1972).
Small quarry directly adjacent to highway. PARK ON RIGHT.
The shale beds in this quarry and in one directly above it are representative of the offshore facies.
Base: In lower quarry thinly bedded siltstone has abundant specimens of Skolithos and Planolites. Isopodichnus is present, but rare. Sandstone in float is packed with specimens of Zoophycos. Note that central tube extends upward (or downward) from bedding plane and that spreiten extend laterally from this tube. This layer is exposed at the intersection of the quarry road and main road.
Upper quarry: Abundant Skolithos, Planolites; rare Bifungites, Arenicolites and possibly ? Teichichnus. Zoophycos common on some surfaces. Note abundant ripple marks.

A3: PALEOENVIRONMENTS OF THE MARCELLUS AND LOWER SKANEATELES FORMATIONS OF THE OTSEGO COUNTY REGION
Prof. Geoscience Dept.
Rochester, New York 14623
Manfred P. Wolff
Prof. Geology Dept.
Hofstra University
Hempstead, Long Island, New York 11550
The Devonian System in New York State varies from carbonates below (Helderbergian, Ulsterian and lowest Erian Series) to coarse continental clastics at the top (Chautauquan Series). And represents a westward migrating deltaic complex built during Middle and Late Devonian time.
This deltaic complex, the Catskill Delta, is today represented by a wedge of sedimentary rock that thickens and coarsens eastward. The clastic wedge is pierced at several horizons by relatively thin, but geographically widespread, lithologically distinct units that do not change facies as rapidly as the rocks above or below. Serving as time planes, these key beds subdivide the clastic wedge into a number of major time-stratigraphic units.
Three carbonate key beds in the lower portion of the wedge serve to subdivide the lowest time stratigraphic unit, the Hamilton Group (Middle Devonian), into four formations, which are from oldest to youngest, the Marcellus, Skaneateles, Ludlowville and Moscow Formations.
The Middle Devonian Hamilton Group of New York State is structurally simple and highly fossiliferous, thereby lending itself to detailed stratigraphic, paleontologic, and paleoecologic studies. In eastern New York it consists of approximately 1,650 feet of shale, siltstones, and sandstones in the Unadilla Valley, 1950 feet in the Susquehanna Valley and 2,285 feet near Richmondville (Cooper 1933).
The Marcellus Formation in the Otsego County region thickens eastward from about 600 feet in the Unadilla Valley, to nearly 820 feet in the Richmondville area in western Schoharie County. The base of the Mottville member is generally taken to be the top of the Marcellus Formation east of the Cayuga Lake meridian. However, east of the Unadilla Valley, the Mottville loses its identity, thereby making the boundary between the Upper Marcellus and Lower Skaneateles almost impossible to delineate with precision. Therefore criteria to determine the exact thickness of the Marcellus Formation across most of Otsego County is lacking.
The senior author, using the Mottville Member as a datum, obtained a dip of approximately 85 feet per mile to the southwest for the Lower Hamilton in the Unadilla Valley. Cooper (1933) indicates steeper dips of 90-100 feet to the southwest in the Susquehanna Valley and 100-137 feet per mile to the southwest in the Schoharie Valley.

STOP 1. road cut on west side Beaver Creek Road
Units Exposed: Mottville (1' Elev. top 1500'), Delphi Station Mbr. (45')
Here the Mottville represents the Camarotoechia-Mucrospirifer Community and delta front sand environment .
The overlying Delphi Station indicates a median delta platform environment. The Limoptera Community is well represented here. Fossils are extremely abundant.

STOP 2. Button Falls
Falls on Button Creek down from Button Falls Road on the West side of the Unadilla Valley about 1 1/2 mi. SW of Leonardsville
Units Exposed: Solsville (8' -Elev. top 1200'), Pecksport (90'), Mottville (l0' -Elev. top - 1300'), Delphi Station (7').
The lithology, sedimentary structures and fauna of the Upper Pecksport assign it to the distal (outer) platform. The slightly sorted sands, sinuous and linguoid ripples, and lag concentrate coquinites of the Mottville probably represent a period of reworking or transgression forming the delta front sands. Camarotoechia and Mucrospirifer also occur in the upper Pecksport and probably represents the same community as the Mottville.

Solsville SS. on left and in abandoned quarry

STOP 3. Plainfield Center Quarry
Just West of Otsego Co. Rd. 21; .3 mi. N of Plainfield Center
Units Exposed: Solsville (10' -Elev. top 1620'), Pecksport (80'), Mottville (5' -Elev. top 1700') .
The Pecksport is here a horizontal to irregular bedded siltstone exhibiting some ripples, burrowing, and cross laminations of the distal (outer) delta platform or in part delta front sands. The Mottville caps the quarry and contains a 5 inch basal coquinite horizon. Large scale, low angle, crossbeds and ripples 1-2 inches thick and trending N 40° E as well as SW are present. Dipolar crossbeds suggest a series of migrating ripples deposited during a period of winnowing and reworking of the delta front sands on the distal (outer) delta platform.

Pecksport in abandoned quarry

Solsville top on left

Village water supply reservoirs on right

Allen Lake on right

Solsville Member on right in pasture

STOP 4. Twelve Thousand Rd. Quarry
1.5 mi. NE of Twelve Thousand
Units Exposed: Panther Mountain (22') or Delphi Station - Mottville interval.
About 22' of dark gray shales and siltstones are exposed here. The lithology and fauna are very similar to the Delphi Station at STOP 1. The assemblage is interpreted as being representative of the Limoptera Community with abundant sessile epifaunal and infaunal filter feeders, mobile infaunal types, non-sessile epifaunal filter feeders and vagrant benthonics.
The top of the quarry is approximately 40' above the Solsville exposed in the pasture .2 mi. to the east. If this exposure is equivalent to the lower Delphi Station, then the Mottville must lie below the floor of the quarry and very near the top of the Solsville. The top of the Solsville must therefore be getting younger eastward from the Brookfield Valley (STOP 1). A high diversity assemblage everywhere occurs above the Mottville from Central New York to Otsego County near below. Therefore, it would seem that the assemblage exposed here is indeed the lower Delphi Station. However, one cannot discount the possibility that a community similar to the Limoptera of the lower Delphi occurs somewhat earlier in time to the east. If we accept this interpretation, the Mottville would be at the top or just above the top of the quarry at this stop. The former interpretation is illustrated below.

Five Mile Point

Exposures of Otsego Shale along Road

Solsville Sandstone on right

STOP 5. Road cut about 1 mi. South of Pierstown
Units Exposed: Panther Mountain (15')
This exposure lies approximately 45' above the top of the Solsville. The fauna contains Paraspirifer, large Tropidoleptus, and Camarotoechia in coquinite lenses. This may be the Mottville equivalent. The environment is delta platform.

STOP 6. Leatherstocking Falls
On Leatherstocking Creek up from NY 80 about 2 mi. North of Cooperstown
Units Exposed: Solsville (100')
The upper portion of the transitional Solsville occurs in the lower part of the falls, while the true Solsville forms the lip. Fossils are rare. A marine delta platform environment is represented by the upper Solsville. Some massive, horizontal bedded and low angle crossbedded sands at the very top of the exposure may represent the Mottville horizon, although this conclusion is very tenuous at best.

Three Mile Point - LUNCH STOP

The Clinton-Sullivan Campaign (1779)
The Clinton-Sullivan Campaign (1779) embarked from this point down the Susquehanna. General Clinton's troops built a dam at the mouth of Otsego Lake, which when broken cleared out the upper portion of the Susquehanna, thereby allowing easier passage of his army on rafts. Clinton's army joined Sullivan's near Elmira to begin a retaliatory campaign against the western Iroquois (Seneca's) in the Finger Lakes - Genesee Region as a reprisal for the Iroquois-Tory attacks on settlements in and near the Mohawk Valley. (Cherry Valley Massacre)

STOP 7. Road cut on Dugway
About 4 mi. North of Cooperstown.
Units Exposed: Otsego 20'
This outcrop contains the massive to thin bedded dark gray shales and arenaceous shales typical of the Otsego. The fauna is of moderate to low diversity of attached and free epifaunal filter feeders. These are the rocks that yield the definite fauna of Cooper (1933). The environment represented is outermost delta platform on upper prodelta slope. Mucrospirifer and Chonetes, unattached epifaunal filter feeders, are very abundant and were adapted to the soft substrates of this environment.

Glimmerglass State Park on left

STOP 8. Cox's Ravine
.5 mi . West of Cherry Valley on County Rd. #54.
Units Exposed: Union Spring (21'), Cherry Valley (5'), Chittenango (7')
The Cherry Valley Limestone forms the lip of the falls and is divisible into a lower and upper division. The Agoniatites nodiferus and Werneroceras plebeiforme Zone occur in the upper Union Springs about 2 feet below the Cherry Valley.
The Cherry Valley Limestone may not always represent a euxinic basin deposit but may represent oscillations of the O-Eh surface sometimes above the sediment - water interface and sometimes below or coincident with that interface. If below the sediment water interface, benthonic forms could become established. (Cottrell 1972, personal communication).

Cherry Valley
This was the site of the Cherry Valley Massacre. On the morning of November 11, 1778 a band of Tories and Indians under the infamous Mohawk chieftain Joseph Brant and the Tory Captain Walter Butler attacked the villages resulting in the deaths of 48 or more residents, mostly women and children. This and other attacks on frontier outposts precipitated the Clinton-Sullivan campaign of 1779.

STOP 9. Road cut on NY 165
Up Weaver Hill 2 mi. East of South Valley
Units Exposed: Solsville (250'), Otsego (50')
A nearly complete section of Solsville is exposed here. The lower portions of the section represent prodelta slope and outer (distal) delta platform deposits. The upper part of the exposure represents the middle or inner (proximal) delta platform environment.

STOP 10. Railroad cut
On Delaware and Hudson Railroad at old depot station.
Unit Exposed: Solsville (6')
This outcrop consists of 1-3 inch horizontal and planar cross-bedded and laminated subgraywackes contained within a set of large (1-2 ft.) ripples. The sandstones are not as sorted as those of other stops. Brachiopod coquinites occur in lenses near the base and at the top of the section. The Solsville here probably represents a nearshore zone of the inner (proximal) delta platform.

A4: GEOLOGIC SETTING OF UPPER SUSQUEHANNA AND ADJACENT MOHAWK REGION OF NEW YORK STATE
David M. Hutchison
Hartwick College
The outcrops and surficial features observed on this trip have been selected (1) to show students the change in lower Paleozoic stratigraphy through time (2) to illustrate several sedimentary and topographic features (3) to help students gain a better understanding of the geologic framework of this area.
The trip starts at the large Upper Devonian flood plain channel behind the F.W.Miller Science Building on the Hartwick College campus in Oneonta and ends in Precambrian garnet gneiss six miles east of Canajoharie. Progressively older beds are exposed to the north because of three factors: the gentle southerly dip of the beds, the erosion by the Mohawk River and the uplift, tilting and erosion of large fault blocks associated with normal faults in the Mohawk River Valley.
The clastic sediments are the result of the Middle Ordovician Taconian Orogeny (470-435 m.y. ago) and the Middle and Late Devonian Acadian Orogeny (J85-355 m.y. ago) (Fisher. 1965). Both of these times of crustal unrest and uplift east of the Hudson River and in New England provided an influx of clays, silts and sands into the Ordovician and Devonian seas which occupied the area of this field trip. The carbonate rocks were deposited by these seas during periods of quiescence between orogenies.

STOP 1. Upper Devonian Oneonta Formation
This outcrop consists of dark grey shales, thinly bedded siltstones and sandstones. A massive sandstone which fills in part of a Devonian stream channel is well exposed for about 150 feet at the left end of the outcrop. There is an erosion surface between the underlying shale and the overlying massive sandstone. This surface which marks the bottom of the channel rises stratigraphically to the right. Interference ripple marks are exposed just below the road level. Plant materials are abundant in some layers and a possible log cast was found at the far right end of the outcrop under the overhanging ledge, but much of this has weathered away. A few galena crystals about 1 cm across have been found in the thinly bedded sandstone.
Trilobites, marine pelecypods and brachiopods of the Gilboa Formation have been found in beds stratigraphically 75 feet below this outcrop.
A clean sandstone which shows extensive through-type cross bedding overlies this outcrop. Red mudstones and shales with root casts, worm burrows and ripple marks are exposed at the top of the hill in new exposures that have been uncovered by recent excavations for a new soccer field.
The view down the valley is looking southeast to Mt. Utsayantha in Stamford (about 30 miles map distance). The broad U-shaped valley is the result of Pleistocene glaciation. The Susquehanna River flows in from the north (out of your view) and through the city of Oneonta. The terraces on either side of the valley are kame terraces. Red beds are exposed near the top of the hills across the valley.

Small kettle hole on right.
This has been partially filled in to make a parking lot for Pyramid Mall.

View to right showing kame terraces across valley.

On right across valley gravel pit in delta kame.

STOP 2. Stop directly across from dam at Goodyear Lake.
The Upper Devonian Gilboa Formation with horizontal sandstones and siltstones is exposed here. The well developed flow-rolls are of interest. It is apparent that these are primary structures (formed while the sediment was still "soft") rather than secondary structures (formed after lithification), but there is some question as to their origin. There are brachiopods, bryozoans, crinoids and pelecypods.

Outcrop of Middle Devonian Cooperstown Shale
Outcrop of Middle Devonian Cooperstown Shale at curve in road. Good view ahead of broad U-shaped valley. The Susquehanna River flows south from its headwaters in Otsego Lake (Cooperstown) in this valley.

Cross Susquehanna River.
Clays indicate a glacial lake occupied this area.

Meander scar of Cherry Valley Creek is visible to left.

Hummocky morainic deposits
After crossing the creek NOTE THE EXCELLENT hummocky morainic deposits showing numerous kettle holes and knob and kettle topography.

Cherry Valley.
The town was settled about 1740. On November 11, 1778 over 40 people were killed by Tories and Indians in the infamous Cherry Valley Massacre.

STOP 3. Highway Department gravel and salt storage area.
Topographically this spot is a break in the Helderberg escarpment. Fairchild interpreted this as a glacial spillway formed at a time when ice filled most of the Mohawk Valley. Meltwater was blocked from draining north and "spilled over" the escarpment eroding the valley (Fairchild, 1925). Fleischer (personal communication and elsewhere in this Guidebook) feels that the valley is the result of glacial scouring of a through valley.
Three formations are exposed here. The lowest formation (exposed about .1 mile down the road) is the Esopus Shale. This is overlain by the Carlisle Center calcareous siltstone which contains numerous worm burrows Toanurus cauda-galli (Rickard and Zenger, 1964). About .l mile south along the road the Carlisle Center siltstone is overlain by the Middle Devonian Onondaga Limestone which contains abundant crinoids, corals and brachiopods.
The upper part of the Onondaga contains abundant chert. Jointing is very obvious at this outcrop.

STOP 4. The Lower Devonian Manlius Fm
The Lower Devonian Manlius Formation (lower Thacher Member) crops out on the right.
This laminated micrite contains some ostracods, tentaculitids and stromatoporids. Some mud crack marks are present. This is the intertidal facies of LaPorte, 1967. The Coeymans Formation rests on top of the Manlius Formation.

STOP 5. Three Middle Devonian formations exposed here.
The lower most formation is the Union Springs Shale which is a black fissile shale containing calcareous concretions. There is a thin limestone near the top of the shale. This is overlain by the Cherry Valley Limestone which is about 7 feet thick and contains a cephalopod fauna. More than 100 feet of the jet-black Fissile Chittenango Shale rests on top of the Cherry Valley Limestone. At the east end (left) of the outcrop the Union Springs Shale has been broken up and sheared indicating some minor faulting.

STOP 6. Lower Devonian Kalkberg Limestone
The Lower Devonian Kalkberg Limestone is exposed in a fresh outcrop. This is a medium grained, thin to medium bedded limestone with abundant chert. There are numerous brachiopods, bryozoans, some corals and trilobite fragments. A 2" thick layer of bentonite is exposed near the eastern end of the outcrop.

STOP 7. (in old quarry) Lower Devonian Coeymans Fm
The Lower Devonian Coeymans Formation consists of a coarse grained thickly bedded limestone with abundant brachiopods, crinoids and corals.

STOP 8 (STOP AT PARK NEXT TO OLD BATHS)
Stop to look at springs and tufa deposits in the city park at the north end of the village of Sharon Springs. There is a strong odor of H2S from the spring water. This is probably caused by the water passing through the underlying thick black shales.

Upper Middle Ord Shales and Sandstones in cliff at left.

Two drumlins are in view to the left.

STOP 9. Canajoharie gorge
Four Lower and Middle Ordovician formations are exposed in Canajoharie gorge.
The lower most formation is the Chuctanunda Creek Dolostone. This is unfossiliferous except for the "hippopotami backs" which are dolomitized hemispherical stromatolites (algal mounds) (Park and Fisher. 1969). Large potholes have formed in the dolostone (Canajoharie is the Iroquois name for the "Pot that washes itself") (Park and Fisher, 1969).
The Middle Ordovician Kings Falls and Sugar River black limestones overlay the dolostone forming a disconformity. These limestones and the thin black shales in them contain abundant trilobite fragments, bryozoans, brachiopods and crinoids.
The limestones are overlain by more than 100 feet of Middle Ordovician Canajoharie Shale.

Cliffs of Upper Cambrian Little Falls Dolostone.
En route to the next stop note the cliffs of Upper Cambrian Little Falls Dolostone.

STOP 10. Precambrian garnet gneiss
Follow the foot path at the east end of the outcrop to the railroad cut. Beware of Poison Ivy along the path and at the Railroad cut.
Rusty weathering Precambrian garnet gneiss exposed along the south side of the road and in railroad cut.
The folded Precambrian gneiss is overlain by the Upper Cambrian Little Falls Dolostone. The dolostone is brecciated for several feet above the contact with the gneiss. Apparently there was movement along the unconformity during Ordovician time when the normal faults in the Adirondack Mountains and the Mohawk River Valley were formed.

Observe the fault-line scarp of the Noses Fault
Observe the fault-line scarp of the Noses Fault from the vehicles. There is a good view of the fault-line scarp on the overpass of Route 55 over the railroad tracks. Note that west of the Noses fault-line scarp the Mohawk River Valley has steep cliffs of Little Falls Dolostone. These are caused by the down cutting of the Mohawk River on the upthrown western side of the fault. East of the fault-line scarp on the downthrown side of the fault-line scarp there are no cliffs.

A5: GLACIAL MORPHOLOGY OF UPPER SUSQUEHANNA DRAINAGE
P. Jay Fleisher
SUNY, College at Oneonta
The purpose of this field trip is primarily to examine the evidence for the glaciolacustrine environment at several different places along the upper Susquehanna drainage. The main stops will emphasize the landforms that characterize the salient aspects of a moraine impounded, ice-contact lake. Included will be various types of moraines and associated outwash, lacustrine plains, hanging deltas and delta-terraces, and strandlines.
The field trip will begin in Oneonta and cover the main Susquehanna Valley between Wells Bridge to the west and Oneonta to the east. The lower reaches of the Charlotte Creek Valley will also be considered. From there the route will mainly follow the Susquehanna north to its headwaters at Cooperstown, with a short diversion into Cherry Valley along the way. From Cooperstown the route will cross a short divide to the west and enter the drainage or Oaks Creek, and continue west and south to traverse the complete Otego Creek Valley. The road log index map shows the general location of each stop.

I-88 parallels the Susquehanna River
I-88 parallels the Susquehanna River for the next 2.4 miles. Much of the area adjacent to the highway on the right (north) was under water during the spring flood of 1977 (probably a 25 year flood).

Flooding from 1977
The valley floor to the north and south of the interstate was flooded to within three feet of covering the highway here during the flood.

Good view of the modern flood plain
The highway rises above the valley floor and provides a good view of the modern flood plain and the abrupt change in valley trend that is a remnant of a preglacial engrown meander. The ridge on the horizon to the right (north) protrudes into the valley along the inside of the meander bend.

The location of STOP 2 is on the left
The location of STOP 2 is on the left, but we won't stop now. Access to this area is possible from County Rd. 48 (locally referred to as the Otego-Wells Bridge Rd.), which we will take on our return to the Oneonta area from Wells Bridge.

Valley plug formed by the Wells Bridge moraine.
Good view to the west of the valley plug formed by the Wells Bridge moraine.

Back of the Wells Bridge moraine
View to the right (north) across the valley includes the back of the Wells Bridge moraine and associated outwash head terrace. The next 1.2 miles provides an excellent overview of the moraine and the breach carved by the Susquehanna River.

STOP 1 Down valley side of the moraine
The eastern end of the parking lot looks over the hummocky relief on the down valley side of the moraine. The common border of the Franklin and Unadilla Quadrangles passes directly through the moraine.
This moraine completely blocked the valley following glacier retreat permitting the damming of a continuous body of water, referred to as Lake Otego, from Wells Bridge to Oneonta. Figure 3 of accompanying paper illustrates the topographic and subsurface aspects of the valley in this area. The moraine is assumed to have been emplaced about 16,000 years BP and breached about 14,000 years BP. We will consider the field evidence for an 1140 feet lake level at the next two stops.
Field work in the Unadilla and Sidney areas indicates that the Upper Susquehanna Lake Chain has greater down valley extent than will be covered in this road log.

Cross Ouleout Creek.

Highway parallels the river for one mile.

Highway climbs onto outwash terrace near mouth of Sand Hill Creek.

Highway follows the Wells Bridge moraine - outwash contact.
Highway drops into Sand Hill Creek incision of outwash and immediately climbs to follow the Wells Bridge moraine - outwash contact.

Crest of moraine on the left, breach on the right.

Charcoal date of 13,000 to 14,500 years BP.
It was within the breach of this moraine that Bob Funk uncovered charcoal while excavating an archeological site in point bar silts that yielded a date of 13,000 to 14,500 years BP. This provides the younger limiting age of Lake Otego.
Road parallels river for 0.6 miles before rising onto outwash head terrace. A correlative terrace can be seen across the valley to the north at an elevation of about 1140 feet.

Fine sand a few tens of feet below the terrace surface.
Excavation for house on the right exposed fine sand under gravel with the contact at the base of the building, a few tens of feet below the terrace surface.

Terrace at about 1120 feet.
White house across the valley to the north is situated on a terrace at about 1120 feet. Other planar landforms can be found along the valley that suggest a second level for Lake Otego below 1140 feet. This may be an interesting prospect to consider as a group.

Deltaic foreset and topset beds
Gravel excavation on right contains deltaic foreset and topset beds indicating current direction to the west down valley.

Deltaic foreset and topset beds
Gravel excavation on left contains deltaic foreset and topset beds indicating current direction to the west down valley.

Road drops to modern flood plain
Road drops to modern flood plain, which is superimposed on Lake Otego lacustrine plain. Lacustrine plain to the left and right for about a mile.

Kame on the right.
Kame on the right. Prior to construction of I-88 a similar but smaller feature could also be seen to the northeast.

Stop 2 is situated to the right, across 1-88,
Stop 2 is situated to the right, across 1-88, on the lower valley wall slope marked by gullies and below "tree line".

STOP 2. Strand line of Lake Otego
Park on the right beyod the overpass and walk south between 1-88 and the forested slope of the valley wall. (Access permission may be requested at the farm directly across 1-88 to the west.) Walk beyond the truncated spur to a gullied area on the left, about 300 yards south of overpass and upslope from the fence.
At an elevation of approximately 1120-1140 feet (2/3 the way up the forest-free slope) pebbly coarse sand, fine sand, silt and a few clay seams were exposed along a gully wall in June 1977. Fluvial channel structures with small scale foreset beds inclined into the slope and down valley rest upon finely laminated, rippled and cross bedded silt and fine sand.
A distinct topographic break in slope can be seen up slope producing a clearly defined bench along the valley wall. A test pit to a depth of 2 to 3 feet revealed well sorted sand lacking stratification and containing occasional pebbles. This was noted repeatedly along this bench at an elevation of about 1140 feet. Another test pit upslope a few tens of feet and farther onto the bench revealed similar sand, lacking stratification as before, but no pebbles.
These sands are interpreted to have formed along the strandline of Lake Otego by wave generated currents that moved into this valley wall alcove. The sand above 1140 feet lacks pebbles and is considered to be of eolian origin, blown up slope from the beach.

Road drops back down to the lacustrine plain at an elevation of 1060 feet.

Outwash/alluvial bench between 1100 and 1120 feet
The highway traverses an outwash/alluvial bench between 1100 and 1120 feet at the confluence of Otego Creek and the Susquehanna River.

STOP 3. West Oneonta delta moraine
Turn right into gravel quarry just short of Otego Creek bridge in West Oneonta. The material exposed here bas been consistently similar to what can be seen here now. Massive foreset beds of coarse pebbly sand and washed gravel are inclined down valley and define to topographic slope to the south. Above are more poorly sorted topset gravels that vary in thickness between 5 and 10 feet. The upper surface is planar and can be traced to the east, where it becomes irregular across Rt . 205.
The northern side of the feature drops in elevation to join a terrace and eventually the flat, poorly drained valley floor. Interbedded and laminated silt and clay dominate this slope and show collapse structures. Occasional rafted clasts can be found within these deposits.
By the nature of the material, its internal structure and topographic expression, this feature is referred to as the West Oneonta delta moraine. The topset-foreset contact is placed at about 1140 feet.

A large kame delta complex
A large kame delta complex begins here on the right and continues for one mile. This may be part of a once larger delta moraine that extended farther into the valley.

A partially dissected left lateral moraine
To the right beyond the Holiday Inn and at the base of the valley wall can be seen the broad crest of a partially dissected left lateral moraine at an elevation of 1340 feet. Its up valley extent can be traced for about a mile, where it is in association with an outwash terrace (probably outwash head) at 1200 feet.

Moraine and terrace
Both the moraine and the terrace can be clearly seen on the right (south). Coe Hill Rd. (dirt) crosses both of them and offers access. On the left (north) side of Rt. 23 is a lacustrine plain at 1100 to 1120 feet.

Highway climbs the kettled margin of the 1200 feet terrace.
Highway climbs the kettled margin of the 1200 feet terrace. Kettles suggest an ice-contact origin. Within the next mile the highway will rise again on the down valley portion of the West Davenport moraine.

Hummocky surface of moraine
Intersection with road on the left that traverses the moraine across the valley and through the Charlotte Creek breach. The hummocky surface of the moraine can be seen along Rt. 23 as you proceed east.

STOP 4. Gravel quarry within a hanging delta.
This excavation provides a look into a large hanging delta that was graded to Lake Davenport at 1260 feet. The lake was dammed behind the dual crested West Davenport moraine and flooded the Charlotte Valley for a number of miles to the east.
The difference between the internal sedimentary structures of this delta and those in a delta moraine reflects the contrasting sedimentary environments of the two. Here discharge is less variable, less sporadic and less energetic. Well sorted topset sand displays a variety of delicate cross bedding, ripples and draped laminations reflecting the progressive decrease in current velocity and increase in water depth.
The best exposures can be found along the northern portion of the excavation. Watch your step when climbing on the exposure and try to keep the dust down.

Back side of the dual-crested West Davenport moraine.
Road climbs off the lacustrine plain and onto the back side of the dual-crested West Davenport moraine. Pine Lake is a kettle hole pond in the moraine.

The road traverses the moraine for the next 3.2 miles.
The road traverses the moraine, and part of the lacustrine plain for the next 3.2 miles.

Dissected and pitted outwash
The road traverses part of the dissected and pitted outwash associated with the West Davenport moraine. The outwash surface blends with the 1180 feet terrace at the Susquehanna-Charlotte Creek confluence.

Deltaic foreset beds are inclined to the southeast.
Morningside Drive on the left leads to the Oneonta Land Fill, where deltaic foreset beds within the 1180 feet terrace are inclined to the southeast indicating a current direction up the Charlotte Creek Valley. This is interpreted to mean the Charlotte was free of ice before the Susquehanna.

Three large gravel excavations
There are three large gravel excavations equally spaced north of Hemlock Rd. over a distance of two miles. Each reveals deltaic internal structure indicating current flow down valley and toward the valley center. Three distinct lobate aspects of the terrace here suggest coalesced lateral deltas that have formed a delta terrace at 1180 feet.

Lobate nature of the terrace margins
View across the valley to the south shows that the 1180 feet terrace position is nearly continuous across the valley floor. This illustrates the lobate nature of the terrace margins in this area and provides a view of the delta-terrace.

Goodyear Lake on the right.

Bedrock floor lies more than 336 feet below the present lake level
Entering Milford Center, where well data from points across the valley indicate the bedrock floor lies more than 336 feet below the present lake level, and is predominantly occupied by quicksand.

Poorly drained, pitted outwash
Proceed across the poorly drained, pitted outwash for 0.2 mile and cross railroad tracks.

Outwash and ablation moraine
For the next 2.4 miles we will be traversing the outwash and ablation moraine (Portlandville moraine) that dammed the Susquehanna to form Lake Milford at 1230 feet. This lake extended up valley to Hyde Park and into the mouth of the Cherry Creek Valley.

Leads to the Crumhorn Mt. wedge locality
Wrightman Rd. intersects County Rd. 35 at white farm house and leads to the Crumhorn Mt. wedge locality discussed in this field guide under the title Wedge-Shaped Structures in Bedrock and Drift.

Good view of the Lake Milford lacustrine plain to the left.

Lacustrine plain
For the past couple of miles the road has primarily been on the lacustrine plain.

STOP 5. Lake Milford strand line
Exposed here on the west side of the highway is 33 feet of interbedded gray and tan clay under 14 feet of interbedded sand and coarse pebbly sand. The sand forms a discontinuous bench at 1230 feet and is interpreted as a Lake Milford strand line.

Surface of hanging delta at 1230 feet
Surface of hanging delta at 1230 feet formed by tributary to Lake Milford. False gain by alluvial fan deposition gives delta a gently inclined up surface.

From here north for about 2 miles the highway is on pitted outwash.

Note morainic topography beginning to develop on the right.

Southeastern extension of the Cassville-Cooperstown moraine
Turn right onto Norton Cross Rd. (unmarked) that crosses Cherry Valley and traverses the hummocky surface of a moraine near Westville. This is the southeastern extension of the Cassville-Cooperstown moraine which is in the Susquehanna Valley to the west.

STOP 6. Cross Cherry Valley Creek where it breaches the moraine.
Pull off to the right just beyond the bridge near the top of the hill.
At the time of emplacement this moraine blocked the valley to an elevation of about 1170 feet forming a dam for Lake Middlefield, a body of water that drowned Cherry Valley for nearly its entire course. The field evidence for Lake Middlefield is in hanging deltas at the mouths of tributary streams, a delta moraine at Middlefield and associated kame delta, and the large lacustrine plain across which the drainage presently meanders. In addition, well data indicate lacustrine sedimentation and the accumulation of thick clay deposits.
The hummocky topography yields down valley to a pitted outwash that was incised by the drainage of Lake Middlefield to form valley train terraces. Up valley the moraine loses relief and joins the lacustrine plain.
Clean exposures in this road cut have revealed the moraine to consist of stratified sand and gravel and not unsorted drift.

Up valley extent of moraine
Up valley extent of moraine can be seen on the left for the next 0.4 miles to where it finally joins the lacustrine plain.

Dissected hanging delta
Road crosses a dissected hanging delta at the mouth of a tributary. Barn on the left is situated on the delta surface at about 1270 feet.

Good view of poorly drained lacustrine plain.

Cross Cherry Valley Creek and lacustrine plain.

Proceed north onto the front of a delta moraine.

Stratified sand and gravel with fluvial cross bedding
Inactive quarry on right at one time revealed stratified sand and gravel with fluvial cross bedding. The road traverses the kettled back portion of the moraine for the next 0.5 miles.

Extension of the delta moraine
The hummocky slope on the right suggests the extension of the delta moraine at the base of the valley wall.

Delta kame to the left.
Dirt road on the left leads to a delta kame that can be seen standing above the lacustrine plain to an elevation of slightly above 1280 feet. Present excavation reveals distinct gravel foreset beds inclined down valley.

Hanging delta/alluvial fan at a B.M. elevation of 1275 feet.
Road crosses a dissected hanging delta/alluvial fan at a B.M. elevation of 1275 feet.

Good view of morainic topography
Road descends valley wall and provides a good view of morainic topography downslope. This may be the upland facies of the Cassville-Cooperstown moraine.

Morainic topography over much of the last mile.

Upland facies of the Cassville-Cooperstown moraine.
Once again the road crosses what appears to be the upland facies of the Cassville-Cooperstown moraine. Note the morainic topography for the next 0.4 mile and discontinuously for the next 2 miles.

This is the outwash portion of the Cassville-Cooperstown moraine.

STOP 7. Cassville-Cooperstown moraine.
To the northwest (across the highway) is the characteristic topographic expressive for the Cassville-Cooperstown moraine. It can be traced in that direction for 5 miles up Oaks Creek to Oaksville. However, from here eastward across the Susquehanna Valley the moraine shows less relief, yet maintains an elevation of about 1250 feet. As the ice retreated from this position a lake remained impounded behind the moraine and grew in size. It is referred to as Lake Cooperstown and reached an upper limit of about 1250 feet. At this elevation it would have been somewhat larger than Lake Otego, which maintains an elevation of 1195 feet at present.
Well data from the vicinity of Hyde Park indicate the bedrock valley floor is in excess of 265 feet below the modern flood plain. The fill is almost entirely quicksand. This depth is consistent with gravity surveys run across the valley between the moraine and the Village of Cooperstown.

Moraine yields to outwash head and tributary deposits.

Baseball Hall of Fame is two blocks to the right.

Farmer's Museum on left, golf course and Otsego Lake on right.
Farmer's Museum on left, golf course and Otsego Lake on right. The golf course is situated on part of a small moraine and outwash surface that bulges slightly into the lake.

Hanging delta at Brookwood Point.
Beginning here and for the next 0.1 miles the road crosses a partially dissected and incised hanging delta at Brookwood Point. The most easily recognized strand line features of Lake Cooperstown are found along the western side of the valley where tributary drainages are larger.

Three Mile Point.
Three Mile Point. Large brown and yellow house on the left occupies the surface of a hanging delta at an elevation of about 1250 feet.

Hanging delta at Five Mile Point
Road climbs onto the hanging delta at Five Mile Point, which also stands at about 1250 feet.

STOP 8. Distal end of delta lobe
Pull into the small parking area on the right 8 next to the sign for the Lakeview Hotel and Cottages. Cross Rt. 60 and walk to the excavation at the back of the Lakeview Hotel.
Distinct foreset-topset structure can be seen in very coarse gravel. The upper surface was measured to be 66 feet above Otsego Lake and determined to have an elevation of about 1255 feet. This being the distal end of the delta lobe there is probably a minimal addition of false gain.
Directly across the lake is Hyde Bay, into which Shadow Brook drains. A gravity survey run across that valley just 0.1 miles from the bay indicates a depth to bedrock of 69 feet. A single water well 0.2 miles up Shadow Brook logged 8 feet of gravel and 62 feet of clay, silt and sand, with the lower contact of the gravel at 1247 feet, indicating that Lake Cooperstown rose to at least that level. Furthermore. Shadow Brook flows across bedrock just 0.5 miles from this well, suggesting a buried channel up valley from Hyde Bay.
Proceed north on Rt. 80 past Six Mile Point, which is also situated on a hanging delta graded to the level of Lake Cooperstown.

Rt. 80 traverses another hanging delta
Rt. 80 traverses another hanging delta at about 1250 feet for 0.4 miles and shows a good example of modern incision. From here north the valley widens and relief diminishes. This is the open end of the Susquehanna through valley.

STOP 9. Lacustrine Clays
Turn right on Otsego County Rd. 53 and park. Walk back to intersection and clean up drainage ditch on southern side. Extremely fine laminated clay in varve-like form was exposed in June 1977. The elevation here is 1220 feet, which would have placed this area under about 30 feet of Lake Cooperstown water.
Since leaving the Otsego Lake trough 2 miles back the terrain has become much more subdued and gentle. The modern sedimentary condition along the northern lake shore is considered to be a good analog of the environment in which these clays accumulated.

Road descends into the valley of Fly Creek.

Cross Fly Creek and lacustrine plain
Cross Fly Creek and the lacustrine plain of a small lake that was ponded behind a moraine at the Village of Fly Creek 3.5 miles down valley (to the left).

Good overview of the lacustrine plain
Road now parallels the valley and provides a good overview of the lacustrine plain on the left.

Road climbs a moraine and follows it for 2 miles
Road climbs a moraine and follows it for 2 miles to Village of Fly Creek. This is part of a large moraine complex that blocked the drainage at Fly Creek and Oaksville.

Proceed west along the continuation of the moraine to Oaksville.
Proceed west along the continuation of the moraine to Oaksville. This is the western extension of the Cassville-Cooperstown moraine that blocked Oaks Creek and dammed Lake Oaksville in the Canadarago Valley.

STOP 10. Cassville-Cooperstown moraine
Pull off to the right and walk into the gravel quarry situated toward the back side of the moraine. Exposed are sorted and stratified sand and gravel, as is typical of moraines in the upper Susquehanna. Although the surface expression is hummocky and irregular, massive foreset beds characterize the internal structure of this part of the moraine. Possibly this accumulated in a delta moraine fashion as the ice retreated from the main moraine position.
The moraine reaches an average elevation of between 1300 and 1320 feet and controlled the water level in Lake Oakeville. Strandline features at this position can be seen in a number of places around Canadarago Lake and at Richfield Springs to the north. Although Canadarago is much smaller and shallower than Otsego Lake (44 feet vs. 166 feet), well information and gravity data indicate it occupies a bedrock basin comparably deep.

Road descends back of moraine
Road descends back of moraine. Lacustrine plain of Lake Oaksville lies ahead.

Across the divide to the drainage of Otego Creek.
Road climbs off the lacustrine plain and across the divide to the drainage of Otego Creek.

Road descends onto flat floored valley.

Two kames and an area of dead ice topography on the left.

Truncated spur on left as road climbs large hummocky terrace form.
Truncated spur on left as road climbs large hummocky terrace form. This terrace, which continues for about a mile, appears to be a complex of dead ice terrain and tributary fan/delta deposits from adjacent short valleys.

Road drops to valley floor and what appears to be a lacustrine plain.

Road climbs a bedrock controlled terrace
Road climbs a bedrock controlled terrace and continues across a glaciofluvial terrace of uncertain origin. This and other similar features can be seen repeatedly along the valley. They are thought to be associated with static or stagnant ice condition that characterized this drainage.

2014: The bridge is gone, so we took a bit of a detour to get here, and we'll go back the same way...
Unload at gate and walk in. At various times during excavation a consistently well defined deltaic internal structure has been observed. Massive foreset gravel and sand dip down valley and are covered by more poorly sorted topset beds, which range in thickness up to 30 feet. This deposit is practically at the center of the valley and has lateral extent. The creek cuts through to the east, where it is forced against the base of a truncated spur. A small tributary enters the valley from the vest and joins Otego Creek slightly to the north.
This feature has the topographic expression of a hanging delta at an elevation of about 1200 feet, but may well be part of a delta terrace deposit or kame delta.
Collapsed wedge-shaped structures have been found at various times in the topset beds. Their occurrence and possible origin are discussed in this guidebook under the title Wedge-Shaped Structures in Bedrock and Drift .

Extensive and continuous terrace level from here south
The road crosses an extensive and continuous terrace level from here south to Laurens and beyond. The terrace scarp maintains an irregular trend marked by several undercut banks where the creek has meandered against the base of the terrace. In spite or this the terrace scarp expresses a lobate trend unrelated to meander scars. This feature is interpreted as a delta-terrace formed by terminal discharge in an ice-contact lake and not considered to be a kame terrace.

Small moraine extends into the valley
Highway traverses a small moraine that extends into the valley and deflects Otego Creek westward.

View of lacustrine plain to the right.

Lateral extension of the West Oneonta delta moraine
Highway crosses the lateral extension of the West Oneonta delta moraine, which can be seen to the right.

A6: PRELIMINARY GEOLOGICAL INVESTIGATION OF OTSEGO LAKE
Boat Trip so no Road Log
John Sales
Willard Harman
P. Jay Fleisher
Ray Breuninger
Michael Melia
SUNY, College at Oneonta
Oneonta, NY
INTRODUCTION AND ACKNOWLEDGEMENTS
This report is a synthesis of the contributions of several workers. All of the ecological aspects, underwater sampling, bathymetry as well as some of the geological interpretation are the result of an impressive ten-year research effort by Bill Harman and his students working at the SUCO Biological Field Station. Use of the field station research vessel as well as the logistics for the lake tour and the lake log are also Harman's contribution. Breuninger contributed the sedimentology and Melia the Paleomalacology in two short studies done in 1974. Fleisher contributed material on the glacial geology and the glacial landforms map and accompanied Sales on an initial reconnaissance of the lake perimeter. Sales pulled together most of the general geology, stratigraphy, physiography and structure and did the actual writing of the shore road log, leaning heavily on the interpretations of Fleisher on the glacial geology. While not contributing specifically to this report, the bedrock mapping done by Rickard and Zenger (1964) provides a firm foundation for many of the interpretations. In pulling the paper together and in fitting other workers' concepts to the local situation, Sales may have distorted some of the concepts of the other workers. Much of this contribution represents preliminary ideas that will require further substantiation and modification. Parts of this paper were updated from Sales, et al., 1972.
GENERAL DESCRIPTION OF THE LAKE (LOCATION AND PHYSIOGRAPHY)
Otsego Lake is in northern Otsego County, New York, 57 kilometers (35 miles) southeast of Utica and 89 kilometers (55 miles) west of Albany. The village of Cooperstown is at its south end and the smaller towns of Springfield and Springfield Center lie a few miles north of the lake. It is within the northern part of the Appalachian (Allegheny) Plateau physiographic province in the extreme northeastern part of the Susquehanna watershed. It is considered to be the source for the Susquehanna River although the actual drainage divide separating Susquehanna from Mohawk River drainage lies about 8 kilometers (5 miles) north of the lake. The Plateau Province is a maturely dissected upland with local hill elevations from 550-670 m. (1800-2200 ft.). Valley elevations are in the 300-430 m. (100-1400 ft.) range. Bedrock under the major valleys lies below 30-90 m. (100-300 ft.) of glacial fill (Gieshen, 1974). There is a NNE-SSW topographic grain, possibly basement controlled, that may have been enhanced by glacial erosion so that the area is dominated by over-steepened and over-deepened troughs with intervening subparallel ridges. Otsego Lake lies in one of these troughs, as does its slightly smaller sister lake - Canadarago - just to the west.

A7: PHYSICAL STRATIGRAPHY, SEDIMENTOLOGY AND ENVIRONMENTAL GEOLOGY OF THE UPPER DEVONIAN STREAM DEPOSITS OF THE CATSKILL MOUNTAINS OF EASTERN NY
This article was not available at the time of binding.

A8: PALEOECOLOGY AND STRATIGRAPHY OF THE ORDOVICIAN BLACK RIVER GROUP LIMESTONES: CENTRAL MOHAWK VALLEY
Barry Cameron
Boston University
Boston, MA 02215
Rami A. Kamal
Geology Department
Texas A & M University
College Station, TX 77843
For over 150 years the Ordovician rocks of the Mohawk Valley have been under study. Some of the leading geologists and paleontologists of the 19th and 20th centuries studied the limestones, shales, and fossils of the Medial Ordovician Black River and Trenton groups in the Black River, West Canada Creek, and Mohawk River valleys (see Kay, 1937. for historical review). As a result, these rocks have become well-known as part of the Medial Ordovician standard reference section of North America.
The purposes of this field trip focusing on the limestones of the Black River Group of southern Herkimer County, New York, are to:
1) Demonstrate the stratigraphic succession and its lateral variations.
2) Discuss and evaluate the age relationships and time correlations of the various formations by
a) Examining the diverse faunas and
b) Demonstrating the lateral continuity of Major lithic and biologic characteristics.
3) Examine and evaluate the criteria for determining the extent and significance of the disconformity along the Black River-Trenton boundary.
4) Examine and evaluate the criteria for determining the environments of deposition and paleogeography.
This field trip guide will summarize some of the previous work on the Black River Group in the Little Falls and Utica 15' quadrangles of Herkimer County and incorporate new data supporting reinterpretations of the stratigraphy in this area. The order of localities has been chosen as conveniently as possible for economy of travel along a southeast to northwest traverse.
Geologic setting
The Little Falls and Utica quadrangles are located along the southwestern margin of the Adirondack Mountains and include part of southern Herkimer County (Fig . 1). Good exposures of Medial Ordovician limestones are to be found along the Mohawk River, West Canada Creek, and East Canada Creek valleys and those of their tributaries (Fig. 1). Many small abandoned limestone quarries in both quadrangles contain exposures of the Black River-Trenton boundary.
Lower Paleozoic strata dip gently to the southwest from the PreCambrian on the northeastern part of the Little Falls Quadrangle (Cushing, 1905), and Precambrian inliers occur at Middleville and Little Falls (Cushing, 1905; Young, 1943; Kay, 1953). The Late Cambrian Little Falls Dolomite underlies the Ordovician rocks and overlies the Precambrian basement complex. A few northeast-southwest trending normal faults cut Paleozoic and Precambrian rocks, e.g., near Little Falls and Dolgeville (Cushing, 1905; Kay, 1937).

STOP 1. Trenton limestones
Small vegetation covered outcrop of Trenton limestones (upper Kings Falls Limestone) on right side of road. Park on the shoulder.
While watching for traffic, cross highway to the small clearing and descend the bank along the small stream at the right (east) end of the clearing. (The stream is not visible until you enter the brush.) Cross stream and walk about 100 feet to the near end of the cliff where 2.5 feet of medium dove gray Lowville Limestone is exposed beneath the coarse, cross-laminated, shelly lower Kings Falls Limestone.

Outcrops of the late Cambrian Little Falls Dolomite
Outcrops of the late Cambrian Little Falls Dolomite on both sides of Route 167. This unit directly underlies the Black River Group in this area.

More outcrops of the Little Falls Dolomite on the right.

Cliffs of Little Falls Dolomite, a thick formation, on the right.

Precambrian gneiss on both sides of highway.
Precambrian gneiss on both sides of highway. This unit underlies the Late Cambrian Little Falls Dolomite in this area.

View of the Mohawk River Valley to the east
North end of parking lot by sign explaining this historic part of New York. A nice view of the Mohawk River Valley to the east can be seen from this upthrown side of the Little Falls Fault (Cushing. 1905, p. 38).

Outcrop of Little Falls Dolomite on left side of road.

Rocklandian and Kirkfieldian (lower Trentonian) limestones
Poor roadside exposures of Rocklandian and Kirkfieldian (lower Trentonian) limestones and shales to the left.
If the power company (Niagara-Mohawk) does not permit trespassing, park and walk across the large bridge. Descend the left (upstream) side to the large limestone exposures at the inside of the meander to see all but the base and top of the Lowville Limestone. The 4 foot thick, burrow-reworked, Watertown-like, sub-tidal facies caps the exposure.

STOP 2. Inghams Mills (locality C99)
Walk to the right, through the grass, and proceed to the right of the tall chain-link fence, walking beneath the powerllne tower. At the stone wall along the edge of the field, bear left and walk along the fence. CAUTION: Poison ivy often grows in abundance along this path. Opposite the brick building, turn right and proceed very carefully over the boulders and across the creek towards the base of the outcrop. The boulders you will have to walk over to get to this exposure are sometimes unstable and move when stepped on. Some are sharp and dangerous.
Four formations of Medial Ordovician age are excellently exposed along with the top of the Late Cambrian Little Falls Dolomite{?) below the dam on East Canada Creek. Lithologies, unusual sedimentary structures, fossils, formation boundaries, and disconformities can be carefully examined.
Little Falls Dolomite(?). Only 2 feet of the Late Cambrian Little Falls Dolomite are exposed at the base of the exposure. This unit is represented by relatively thick-bedded, light to medium brown weathering, quartz arenitic, pyrite-bearing dolostone with thin interbedded shale layers.
Lowville Limestone. About 29.5 to 30 feet of Lowville Limestone are excellently exposed with a thick dove gray shaly limestone at the base. The lowest 2 to 3 feet exhibit a slump and boulder beachrock (Figs. 5-6) containing limestone blocks up to 2.5 feet in diameter, that probably formed as a result of instability over the irregular depositional surface of the Little Falls Dolomite. This might be a channel margin slump, e.g., bank collapse deposit.
The next 16.5 feet contain horizontally laminated (algal?), dove gray calcilutites with abundant vertical burrows (Phytopsis), a few ostracodes. and frequent stylolites. Frequent mudcracks confirm an intertidal origin. A tidal channel (Figs. 5, 7) is wholly exposed on the west side of the outcrop (old stream channel).
Between 16.5 and 21.5 feet an apparently subtidal, irregularly burrowed, essentially non-laminated, massively bedded, dark gray to black calcisiltite zone contains Foerstephyllum halli, Lambeophyllum profundum, Hormotoma, Loxoplocus, Isotelus, cryptostome bryozoa, straight nautiloids and pelmatozoan debris. This resembles the subtidal Watertown Limestone to the northwest.
Immediately above these deeper water sediments, the intertidal facies begins to reappear. This is a vertically burrowed, horizontally laminated (algal?), limestone intraclast-bearing, fossiliferous calcilutite and calcisiltite zone. Fossils from this interval include Tetradium cellulosum, Eoleperditia fabulites, Lambeophyllum profundum, Isotelus, cryptostome bryozoa, and pelmatozoan fragments. Near the base of this zone a sediment-filled tidal meander(?) or channel (Cameron, 1969, see Fig. 7) up to 7 feet wide and 2 feet deep is excellently exposed in 2 faces of the outcrop. Note the structure and composition of the sediments filling it.
At about 27 feet, a 9 inch thick calcilutite bed contains scores of whole Tetradium cellulosum colonies in life position that cover 50% to 90% of the bed which contains a thin veneer of limestone pebble conglomerate. One can readily see how the fine-grained sediment was trapped in and around these delicately branching tabulate corals. This is also equivalent to Walker's (1973) wave-baffle lithology and it resembles his House Creek Member of the Lowville Limestone in northwestern New York (Fig. 8; see Fig. 8 of Cameron, 1969).
The top of the Lowville Limestone is riddled with burrows (dominantly vertical) partially filled with the black lustrous carbonaceous mineral anthraxolite. Several inches of irregular relief over the top of this bed may mark a disconformity between the Black River Group and the Trenton Group.
Trenton Group. The lowest 13 feet of the Trenton(?) limestones can be divided into 7.5 feet of chocolate brown weathering interbedded calcareous shales and argillaceous calcisiltites at the base and 5.5 feet of medium gray weathering interbedded thinner shales and less argillaceous calcisiltites above. The contact between these 2 subdivisions is slightly gradational. The surfaces of the limestone layers exhibit extremely well-developed loading casts. In addition, the lower subdivision contains an unusually well-developed and fully exposed intraformational fold similar to those described by Chenowith (1952) from the Sugar River Limestone in northwestern New York. Fossils are common. The fauna of the lower 7.5 feet is that of the uppermost Black River Group. i.e., the Selby Limestone of northwestern New York (Cameron and Mangion, 1977), while the fauna of the upper 5.5 feet resembles that of the lower Trentonian Napanee Limestone. Overlying these limestones is the 38 foot thick Kings Falls Limestone with basal conglomerates.

STOP 3. Small quarry (locality C107)
Walk into small old quarry about 100 feet into field from right side of road. The Black River-Trenton boundary is well-exposed along the contact between 8 feet of upper Lowville Limestone and 13 feet of lower Kings Falls Limestone. The very shaly lowest 13 feet of Trenton(?) limestones seen at Stop 2 is absent and pebbles of the Lowville Limestone can be seen in the lowest few inches of the Kings Falls. There is little relief along this contact to suggest a disconformity. The thickest section of the Lowville occurs at the axis of the fold at the far end of the quarry. Shales are rare. Fossils are uncommon but include Isotelus, Eoleperditia fabulites, small ostracodes, Liospira, and cryptostome bryozoa. Tetradiurn cellulosum is absent.
The very fossiliferous Kings Falls Limestone exhibits the somewhat typical cyclic nature of burrowed finer-grained calcarenites and calcisiltites alternating with cross-laminated, coarse-grained calcarenites and coquinites.

STOP 4. Small quarry (locality C168)
Walk along dirt road into small old quarry (now a private dump about 100 feet into woods from right side of road (Route 169)).
At this stop, we shall (1) examine metabentonites at the base of the Kings Falls Limestone and (2) reexamine the Black River-Trenton boundary between the upper Lowville and lower Kings Falls limestones. The top of the Lowville has 1 to 2 inches of relief, possibly due to scouring since bedding laminae are truncated. The shaly and argillaceous limestone interval between 2 and 3 feet appears to form a marker zone that can be traced from here northwestward to Newport. Tetradium is absent. The 4.5 foot sandy lower member can be seen in the lower quarry. The Lowville is about 11.5 feet thick at this locality.
The fossiliferous Kings Falls contains cream-colored, sticky, 2 to 3 inch thick metabentonites at 12 and 29 inches. A similar 2 inch thick clay has been reported at 2 feet from Stony Creek one-half mile to the southeast (Craig, 1941; Kay, 1943, 1953). We shall evaluate the significance of these clays for time-correlation at the next stop.

Quarry on right is in Little Falls Dolomite.

STOP 5. City Brook (locality C1)
Walk onto bridge and look upstream towards the falls. This outcrop hss been CLOSED to trespassers, but we can look and talk here.
The characteristics of the Lowville and lower Trenton limestones will be compared with those at previous stops. The Lowville Limestone lies disconformably on the quartz arenite-rich Late Cambrian Little Falls Dolomite below the bridge. The lower falls is supported by the upper Lowville Limestone, and the upper falls (Craig, 1941, Fig. 5; Kay. 1953, Fig. 11) is supported by the middle Kings Falls Limestone.
Lowville Limestone. The lower 7 feet are tan weathering, gray, quartz arenite-rich, ostracode-bearing, impure, thick-bedded, medium-textured, dolomitic, argillaceous limestones interbedded with a few calcareous shales up to 3 inches thick. Vertical burrows are abundant. A 3 inch thick metabentonite occurs at 6' 9" (Kay, 1943, 1953). Kay (1953) correlated this with a prominent reentrant at the top of this lower member at Newport Quarry (Stop 18. Fig. 5).
The upper 19.5 feet of the Lowville is composed of relatively pure, light gray weathering, dove gray, conchoidally fracturing calcilutite (sublithographic) and some calcisiltites. Stylolites are abundant from 11 to 16 feet. Thin shales are frequent between 13 and 16 feet, at the 18th foot, and especially between 19.5 and 21.5 feet where the limestones are very argillaceous (argillaceous marker horizon). Vertical burrows (Phytopsis) are abundant between 11 and 16 feet and in the top foot. Mud-cracks occur above and below the 25th foot. An intertidal origin seems probable for these limestones. Tetradium is extremely rare in the upper few feet.
Kings Falls Limestone. Sediment from a coquinal calcarenite bed at the base of the Kings Falls fills some of the burrows in the highly burrow-reworked calcilutite bed at the top of the Lowville. The Kings Falls is characterized by coquinal calcarenites, as at previous localities. Cross-laminated and pararippled beds are frequent.
At 7 feet a deep reentrant marks where a metabentonite is weathering out. Less than a mile north, at Buttermilk Creek (Stop 6), this clay is 9 feet above the base of the Kings Falls (Kay, 1953). If this altered volcanic ash near the base of the Kings Falls between Stony Creek and Buttermilk Creek is part of a single bed, then it represents a synchronous time surface indicating that this formation is onlapping the Lowville eastward. Therefore, the base of the Kings Falls becomes progressively younger eastward, increasing the gap in time marked by the Black River-Trenton boundary in that direction (Fig. 3).

Herkimer diamonds are common in the Little Falls Dolomite downhill to the left.

STOP 6. Buttermilk Creek (locality C101)
Descend to the creek from the bridge and walk upstream. The Little Falls Dolomite comprises the stream bed at the bridge. As you walk upstream, you will walk through the Lowville Limestone and eventually reach the Trenton limestones (Kings Falls).
The lower sandy member (11-12 feet) of the Lowville can be seen roughly between 2 broad flat areas in the stream bed. The 23-24 foot thick upper Lowville is fully exposed as you walk further upstream. The argillaceous marker horizon (about 2 feet thick) occurs 6 feet below the top. From 2 to 5 inches below the top there are pieces of the colonial tabulate coral Tetradium. Beneath the Tetradium, vertically burrowed calcilutites dominate down to the marker horizon. The uppermost 1 to 2 inches contain a strophomenid-rich layer resembling the top of the Watertown Limestone at the next stop (Stop 7).
The Kings Falls Limestone, disconformably overlying the Lowville, is shelly, shaly, pararippled, cross-laminated, and sheet-laminated. A metabentonite, reviewed at City Brook (Stop 5), occurs at 9 feet above the base. The Trenton Group at this outcrop is described in more detail by Cameron, Mangion and Titus (1972).

STOP 7. Small hillside quarry exposures (locality C112A)
Open gate, go through, CLOSE GATE, and walk uphill to last major exposure in field (about 100 feet from road). Return to cars by way of gate. Be sure it is closed when you leave.
The Watertown burrow-reworked lithology first appears as about a 1 foot thick, but recognizable, lithology at this locality. It can be distinguished from the subjacent vertically burrowed calcilutites of the Lowville and the superjacent calcarenites of the Kings Falls. Large tabulate corals (Poerstephyllum halli) and rugose solitary corals are present, as in some exposures farther northwest, but black chert is absent here. Only the 2 inch thick strophomenid brachiopod-rich bed at this locality is represented at Buttermilk Creek less than a half mile south.
Whole Tetradium cellulosum colonies can be found in the uppermost five inches of the Lowville whose argillaceous limestone marker bed is exposed 6 feet below the top. Between the Tetradium and the marker zone, vertically burrowed calcilutites predominate, as at Buttermilk Creek (Stop 6). This upper Tetradium horizon resembles the upper Tetradium beds at Inghams Mills (Stop 2) and Walker's (1973) House Creek Member of the Lowville of northwestern New York.

STOP 8. Northwest Newport Quarry (locality NPQ)
Walk about 150 feet along the gravel road and then descend the grassed slope to the upper quarry where the Watertown Limestone caps the quarry wall which is composed mostly of Lowville Limestone. The top of the quarry here is beginning to collapse, so stay well clear of the edge. Enter at your own risk. After examining the top of the Watertown, continue to descend the grassed slope (overgrown old road) to the quarry floor. Bear left to examine fallen blocks of the Watertown and upper Lowville. Bear right all around a promontory to the southeast part of the quarry where the lower and middle Lowville can be examined safely in the quarry wall. Climb up over the rubble to the gravel road to return to the cars.
The lower dolomitic and sandy member of the Lowville is about 15.5 feet thick. Its contact with the upper 21.5 feet is gradational. The 2 foot thick argillaceous marker horizon occurs about 6 feet below the Watertown Limestone. Tetradium have not been found in the upper Lowville here. The top of the Little Falls Dolomite presumably forms the quarry floor.
The Watertown Limestone is highly burrow-reworked, black chert-bearing and fossiliferous. The fauna is diverse but hard to collect. Corals are common as well as brachiopods and mollusks.
The contact with the Kings Falls Limestone is exposed in a quarry southwest of Newport (Kay, 1953), but not here.

A9: PALEONTOLOGY OF THE LOWER TRENTON GROUP OF CENTRAL NEW YORK STATE
Robert Titus
Hartwick College
The lower Trenton Group contains a broad spectrum of carbonate environments ranging from shallow nearshore to relatively deep offshore facies. Well preserved, diverse and abundant fossil assemblages are found at all stratigraphic levels. Many good, easily accessible outcrops are available for field demonstrations of principles of fossil community analysis and marine paleoecology. These outcrops extend from Canajoharie to Watertown and beyond into Ontario. However most of the major facies can be visited within a short belt extending from Little Falls to Middleville. This field guide will focus on this area.

STOP 1. Exposure of the Dolgeville Facies
Outcrop along the road is an exposure of the Dolgeville Facies and contains remains of the Triarthrus Community. In the summer and early fall this outcrop is likely to be well grown over but in the spring it is an excellent exposure. The best fossil collecting is on thin brown shales where ostracodes are very abundant. Fissile black shales often yield abundant remains of Triarthrus, other trilobites and brachiopods. Also present at this outcrop are folds in the strata produced while the sediment was still soft. Above the thruway overpass is an excellent exposure of the Dolgeville Facies. Unfortunately the State Troopers will throw you off of this outcrop if they see you.

Side trip A: Abandoned Quarry
Side trip A: We will not visit the quarry on this field trip because at this time of the year the quarry is badly overgrown and very difficult to get into. However, in the spring this is a good exposure of the lower Kings Falls Limestone. The quarry contains abundant remains of the Liospira Community.

Side trip B: Denley Limestone and Sugar River Limestone
Side trip B: Upstream are good exposures of the Poland Member of the Denley Limestone which contain very sparce remains of the Geisonoceras Community in generally barren calcisiltites. Downstream are good exposures of the Sugar River Limestone containing abundant remains of the Trematis Community.

STOP 2. Quarry with Lowville Limestone
This is a larger quarry than at first appearance. Around toward the back of it is a good exposure of the Lowville Limestone. About 17 feet of this formation is exposed. Lying unconformably upon this unit is the Kings Falls Limestone. The lower beds are very shelly but overlying strata become finer grained. The lower five feet contain elements of the Triplesia Community (Schizocrinus, Streptolasma and a great abundance of Sowerbyella). Overlying these beds are strata containing typical Liospira Community faunas. A bentonite lies a few feet above the base of the Kings Falls Limestone. Towards the back of the quarry there is the waterfall of an intermittent stream. Following this stream bed one can see discontinuous exposure of nearly the whole Trenton Group. Beds containing assemblages from the Encrinurus, Trematis and Geisonoceras communities are exposed here.

STOP 3. Exposure of the Kings Falls and Sugar River Limestones.
This road outcrop shows an exposure of the Kings Falls and Sugar River Limestones. The lower 10 feet contain remains of the Liospira Community. The next 20 feet contain assemblages from the Encrinurus Community and the uppermost beds contain Trematis Community faunas. Just above the road outcrop Maltanner Creek crosses the road. Stream outcrops expose a complete section of the Trenton Group from its base to the lower most Denley Limestone. This section is of historical interest because it was intensely studied by James Hall in the early 1840's. Probably 50 or more species were originally described from this outcrop. Unfortunately while this land is not posted the owner is apt to throw people off of his property.

STOP 4. Shedd Brook - Kings Falls Limestone to the Denley Limestone.
This is Shedd Brook which shows an exposure ranging from the upper Kings Falls Limestone to the Denley Limestone. Strata containing assemblages from the Encrinurus, Trematis and Geisonoceras communities are exposed. Of greatest interest are the beds just below the parking lot. These contain a great abundance of nautiloids most of which are of the genus Geisonoceras. These beds represent assemblages of the Geisonoceras Community. Also present are Endoceras, and Trocholites in moderate abundances.

A10: THE STRUCTURAL FRAMEWORK AND STRATIGRAPHY OF THE SOUTHEASTERN ADIRONDACKS
James McLelland
The southeastern Adirondacks are herein defined as the topographic highlands (overwhelmingly Precambrian) that lie within a compartment whose corners are situated at: Speculator, Gloversville, Saratoga Springs, and Glens Falls (see f1g. 3). The southeastern Adirondacks are part of a regional geologic framework that underlies the map area shown in fig. 1. The lithology and structure of this region is shown in figs. 3 and 4. The purpose of this trip is to show as many examples of this area's representative lithology and structure as time permits.

Cross the Sacandaga River.
For the next 3.5 miles all exposures have been within the Sacandaga Fm. The large hills immediately to the south are underlain by vertically dipping paragneisses and metagabbros situated on the hinge line of the Canada Lake Nappe. Note the southerly dips of the Sacandaga Fm.; these define the southern limb of the Piseco Anticline.

Leaving Sacandaga Fm.
Leaving Sacandaga Fm.; enter quartzo-feldspathic gneisses "a" of the Piseco Anticline. For the next 4 miles all exposures lie within these gneisses.

STOP 1. Pumpkin Hollow.
Large road cuts on the east side of Rt. 30 expose excellent examples of the Sacandaga Fm. At the northern end of the outcrop typical two pyroxene-plagioclase granulites can be seen. The central part of the outcrop contains good light colored sillimanite-garnet-microcline-quartz gneisses (leucogneisses). Although the weathered surface of these rocks are often dark due to staining, fresh samples display the typical light color of the Sacandaga Fm. The characteristic excellent layering of the Sacandaga Fn. is clearly developed. Note the strong flattening parallel to layering.
Towards the southern end of the outcrop calc-silicates and marbles make their entrance into the section. At one fresh surface a thin layer of diopsidic marble is exposed. NO HAMMERING, PLEASE. Many "punky" weathering layers in the outcrop contain calc-silicates and carbonates.
At the far southern end of the road cut there exists an exposure. Here there is exposed the contact between the quartzo-feldspathic "a" gneisses of the Piseco Anticline and the overlying Sacandaga Fm. The hills to the south are composed of homogeneous quartzo-feldspathic type "a" gneisses coring the Piseco Anticline (note how ruggedly this massive unit weathers). The Sacandaga Fm. at Stop 1 has a northerly dip off the northern flank of the Piseco Anticline and begins its descent into the southern limb of the Glens Falls Syncline. No angular discordance or metamorphosed soil profile can be discerned at the base of the Sacandaga Fm. However, this does not preclude the prior existence of an angular discordance. Intense deformation often erases all traces of earlier angular discordance (Balk 1936).
Along most of the road cut there can be found excellent examples of faults and associated pegmatite veins. Note that the drag on several of the faults gives conflicting senses of displacement. The cause of this is not known to the author. Also note the drag folds which indicate tectonic transport towards the hinge line of the Piseco Anticline.

Entrance to Sacandaga Public Campsite.
On the north side of the road are quartzo-feldspathic gneisses and calc-silicates. These are probably within the Lower Lake Durant Fm. Anorthositic and gabbroic rocks have intruded here and locally steep dips may be related to this.

Silver Bells Ski are to east.
The slopes of the ski hill are composed of excellent gabbroic anorthosite and anorthositic gabbro. These appear to be intrusive into the Upper Marble Fm. These intrusives may be related to the Speculator Mt. anorthosite sheet and can be traced eastward into anorthositic rocks of the Tenantville Complex which is exposed in the region near Tenantville in the large saddle of the Piseco Anticline several miles to the east.
The town of Wells in underlain by Lower Paleozoic sediments which have been down dropped by a set of steep N20E faults that result in a local dome and graben complex. The mapped offset of PreCambrian stratigraphy across these faults indicates that, if the displacement vectors were vertical, the throw is of the order of 3500 ft.

We are now near the hinge line of the Glens Falls Syncline.

To the west are charnockitic gneisses assigned to the Blue Mt. Fm.
To the west are charnockitic gneisses assigned to the Blue Mt. Fm. Note the southerly dips as we are located here on the north flank of the Glens Falls Syncline.

Garnetiferous leucogneisses of the Upper Marble Fm
Beginning at the intersection are good exposures of garnetiferous leucogneisses of the Upper Marble Fm. Lithologically these are similar to the leucogneisses seen in the Sacandaga Fm. at Stop 1, however, they lack the good layering that characterizes the Sacandaga.
At the junction itself there are good exposures of fault breccia associated with one of the NNE faults responsible for the Paleozoic inlier at Wells.
For the next mile the highway passes just above the contact of the metastratified sequences and anorthositic rocks of the Oregon Dome. These anorthosites form the large hills across the stream valley to the northeast.

Leaving the Upper Marble Fm.
On the north side of the highway are cuts through garnetiferous amphibolite, calc-silicates, marbles, and quartzites of this unit.

Small outcrop of quartzo-feldspathic gneiss in the Lake Durant Formation.

STOP 2. One half mile south of southern intersection of old Rt. 30 with new Rt. 30.
On the west side of the road small road cut exposes a splendid example of Adirondack anorthositic gneisses that are intermediate in character between the so-called Marcy type (uncrushed) and the Whiteface type (crushed). About 50% of the rock consists of partially crushed crystals of andesine plagioclase. Some of these crystals appear to have measured from 6-8" prior to cataclasis. Excellent moonstone sheen can be seen in most crystals. In places ophitic to subophitic texture has been preserved with the mafic phase being represented by orthopyroxene.
In addition to the coarse grained anorthosite there exists a fine grained phase and a clearly crosscutting set of late orthopyroxene rich dikes. The latter may represent a late mafic differentiate related to cotectic liquids responsible for the ophitic intracrystalline rest magma. This would be consistent with the iron enrichment trend characteristic of Adirondack igneous differentiation. The fine grained phase may have intruded early in the sequence, but this is uncertain.
Near road level there can be found several inclusions of calcsilicate within the anorthositic rocks. These are believed to have been derived from the Lower Marble Fm. and are consistent with a non-basement status for the anorthosite.
The upper, weathered surface of the outcrop affords the best vantage point for studying the textures and mineralogy of the anorthositic rocks. In several places there can be seen excellent examples of garnet coronas of the type that are common throughout Adirondack anorthosites. These coronas are characterized by garnet rims developed around iron-titanium oxides and pyroxenes. Recently McLelland Whitney (1977) have succeeded in describing the development of these coronas according to the following generalized reaction:
Orthopyroxene + Plagioclase + Fe-bearing oxide + quartz + garnet + clinopyroxene
This reaction is similar to one proposed by de Waard (1965) but includes Fe-oxide and quartz as necessary reactant phases. The products are typomorphic of the garnet-clinopyroxene subfacies of the granulite facies (de Waard 1965). The application of various geothermometers to the phases present suggests that the P, T conditions of metamorphism were approximately 8 Kb and 650-700° C respectively.

Long road through the lower portion of the Lake Durant Fm.
Long road cuts parallel to strike through the lower portion of the Lake Durant Fm. These are characteristically composed of well layered pink quartzo-feldspathic gneisses, thin amphibolites, and calc-silicates. The quartzo-feldspathic lithologies are dominant and become increasingly so proceeding up from the basal units. At this locality the increase in quartzo-feldspathic material is accompanied by the development of K-feldspar megacrysts.

On west side of road are extensive cuts in the Upper Marble Fm.
On west side of road are extensive cuts in the Upper Marble Fm. Quartzite, calc-silicate, and sillimanite-garnet-quartz-feldspar leucogneisses are especially well developed here. Some marble and charnockite are present. The large hills to the southeast consist of anorthositic gneisses in the Oregon Dome. The rocks exposed along the highway dip off the dome.

STOP 3. 3.3 miles east of Speculator, New York.
The Upper Marble Fm. is exposed in road cuts on both sides of the highway. These exposures show typical examples of the extreme ductility of the carbonate rich units. The south wall of the road cut is particularly striking, for here relatively brittle layers of garnetiferous amphibolite have been intensely boudinaged and broken. The marbles, on the other hand, have yielded plastically and flowed with ease during the deformation. As a result the marble-amphibolite relationships are similar to those that would be expected between magma and country rock. Numerous rotated, angular blocks of amphibolite are scattered throughout the marble in the fashion of xenoliths in igneous intrusions. At the eastern end of the outcrop tight isoclinal folds of amphibolite and metapelitic gneisses have been broken apart and rotated. The isolated fold noses that remain "floating" in the marbles have been aptly termed "tectonic fish." Features such as those seen within this road cut have led this writer to question the appropriateness of assigning an unconformity to the base of the Lower Marble Fm. Tectonic phenomena in rocks of high viscosity contrast can account for the fact that the marbles are able to come into contact with a variety of lithologies. A variety of interesting lithologies are present in this road cut. The marble itself contains diopside (now serpentinized), tourmaline, graphite, chondrodite, phlogopite, and a variety of pyrites. Interesting reaction rims, or selvages, exist between the marbles and quartz rich boudins. Presumably these selvages reflect the influence of compositional gradients during metamorphism.
Most of the amphibolites in the outcrop are highly garnetiferous and some layers appear to contain 60-70% garnet. The garnets are almandine rich and are similar to those at Gore Mt. However, it is not known whether these amphibolites represent metamorphosed sedimentary or igneous rocks. Note that a number of the garnets are separated from surrounding hornblende by narrow light colored rims. These consist of calcic plagioclase and orthopyroxene and represent products of the reaction:
Garnet + Hornblende = Orthopyroxene + Calcic Plagioclase + Water
This reaction is characteristic of the granulite facies wherein the association garnet plus hornblende is unstable (de Waard 1965).
Also present in the outcrop are various layers rich in calcsilicates. One of these contains coarse, pale diopside crystals several inches across. Others consist almost entirely of green diopside. Tremolite has also been found in some layers. Rusty weathering, metapelitic units are rich in graphite, calc-silicates, and pyrite. Grossularite, scapolite, and wollastonite, and sphene have been recognized in thin section.
Near the west end of the outcrop a deformed layer of charnockite is well exposed. In other places the charnockite-marble interlayering occurs on the scale of one to two inches.
Exposed at several places in the road cut are striking, cross-cutting veins of tourmaline and quartz displaying a symplectic type of intergrowth. Other veins include hornblende and sphene bearing pegmatites.
Commonly included in the Upper Marble, but not exposed here, are quartzites, kinzigites; sillimanite rich, garnetiferous, quartz-microcline gneisses; and fine grained garnetiferous leucogneisses identical to those characterizing the Sacandaga Fm. These lithologies may be seen in road cuts .5 mile to the south.
Almost certainly these marbles are of inorganic origin. No calcium carbonate secreting organisms appear to have existed during the time in which these carbonates were deposited (1.1 b.y. ago). Presumably the graphite represents remains of stromatolite-like binding algae that operated in shallow water, intertidal zones. If so, the other road cut lithologies formed in this environment as well. This seems reasonable enough for the clearly metasedimentary units such as the quartzites and kinzigites. The shallow water environment is much more interesting when applied to the charnockitic and amphibolite layers. The fine scale layering, and ubiquitous conformity of these, strongly suggests that they do not have an intrusive origin. Perhaps they represent the metamorphosed products of volcanic material in a shelf like environment. Such intercalation is now occurring in many island arc areas where shallow water sediments cover, and in turn are covered by, ash and lava. Alternatively they may represent metasediments.

For the next 14 miles exposures are limited.
For the most part, however, we shall be passing through the quartzo-feldspathic gneisses "a" that cover the Piseco Anticline.

STOP 4. Hinge line of Piseco Anticline
Hinge line of Piseco Anticline near domical culmination at Piseco Lake. The rocks here are typical quartzo-feldspathic gneisses "a" such as occur in the Piseco Anticline and in other large anticlinal structures, e.g. Snowy Mt. Dome, Oregon Dome.
The pink "granitic" gneisses of the Piseco Anticline do not exhibit marked lithologic variation. Locally grain size is variable and in places megacrysts of K-feldspar may be seen. In the present outcrop these megacrysts appear to have been largely granulated and only a few small remnants of cores are seen. The open folds at this locality are minor folds of the F2 event. Their axes trend N70W and plunge 10-150 SE parallel to the Piseco Anticline.
The most striking aspect of the gneisses in the Piseco Anticline is their well developed lineation. This is expressed by rod, or pencil-like structures. Often these consist of alternating ribbons of quartzite, quartzo-feldspathic gneiss, and biotite rich layers. In many instances these ribbons represent transposed layering on the highly attenuated limbs of F1 minor folds. Near the northeast end of the road cut such F1 minor folds are highly visible because the presence of quartzites in the stratigraphy enhances their visibility. Slabbed and polished specimens from this and similar outcrops demonstrates that these F1 folds are exceedingly common in the Piseco Anticline. Examination of these F1 folds shows that the dominant foliation in the rock is axial planar to them. Similarly, layer transposition is related to flattening parallel to the axial planes of F1 folds. The intersection of F1 axial plane foliation and earlier compositional surfaces helps to define the strong lineation in the outcrop. In addition to this a number of rod-like lineations are probably the hinge line regions of F1 minor folds which are difficult to recognize because of apparent lithologic homogeneity. Lineation in the outcrop is further intensified by the fact the upright and relatively open F2 folds are coaxial with F1. Thus the intersection of the F1 and F2 axial planar foliations results in a lineation parallel to the two fold axes. Moreover, F2 minor folds are often of the crenulation variety and their sharp hinge lines define a marked lineation in the F1 foliation.
As described above, a number of parallel elements combine to produce an extremely strong lineation in the Piseco Anticline. Past observers have sometimes remarked that the lineation appears to be the result of stretching parallel to the long axis of the Piseco Dome. However, the lineation is probably unrelated to "stretching" and is more realistically explained as an intersection lineation of S0, S1, and S2 elements . Moreover, the intensity of the lineation is more the result of the early F1 recumbent folding and flattening than it is of the later, coaxial F2 Piseco Anticline.

Red stained quartzo-feldspathic gneisses
On both sides of Rt. 10 are red stained quartzo-feldspathic gneisses "a" that have been cataclastized by a large N20E fault zone. For the next 5.5 miles we shall pass through a number of road-curves as Rt. 10 makes its way through the core rocks on the south limb of the Piseco Anticline.

Cross into the Sacandaga Fm.

Parking area on east side of highway.
The rocks here are quartzo-feldspathic gneisses believed to be part of the Sacandaga Fm.

STOP 5. Shaker Place.
The northernmost road cut consists of a variety of metasedimentary rocks. These lie directly above the Piseco Anticline and are believed to be stratigraphically equivalent to the Sacandaga Formation. The outcrop displays at least two phases of folding and their related fabric elements. Thsse are believed to be F1 and F2. Both axial plane foliations are well developed here. Several examples of folded F1 closures are present and F1 foliations (parallel to layering) can be seen being folded about upright F2 axial planes.
Further to the south, and overlooking a bend in the west branch of the Sacandaga River, there occurs a long road cut consisting principally of pink and light green quartzo-feldspathic gneisses. About half-way down this road cut there occurs a very large and impressive boudin of amphibolite and diopsidic gneiss. To the north of this boudin the quartzo-feldspathic gneisses are pervasively intruded by anorthositic gabbros, gabbroic anorthosites, and various other related igneous varieties. At the north end of the cut and prior to the metastratified sequences these intrusives can be seen folded by upright F2 axes. They are crosscut by quartzo-feldspathic material.
Three important conclusions emerge from study of this outcrop. The first is that the anorthositic suite is intrusive into rocks at, and above, the stratigraphic level of the Lower Marble or Sacandaga Fm. In the second place, while the anorthositic rocks are clearly involved in F2 folding, they do not show, and in fact transect, F1 foliation. Thirdly, the quartzo-feldspathic rocks intruded by the anorthosites appear to have undergone substantial anatexis in the vicinity of the intrusion. This is suggested by the cross-cutting quartzo-feldspathic material and by the overall appearance of the gneisses along the road cut.

Excellent examples of anorthositic gabbros
Road cut on west side of highway shows excellent examples of anorthositic gabbros intrusive into layered pink and light green quartzo-feldspathic gneisses. The presence of pegmatites and cross-cutting granitic veins is attributed to anatexis of the quartzo-feldspathic gneisses by the anorthositic rocks.

Fine grained metagabbro on west side Rt. 10.

Excellent road cut in coarse anorthositic gabbro.
Excellent road cut in coarse anorthositic gabbro. Ophitic to subophitic texture well preserved. Garnets are sporadically developed and tend to be associated with coarse gabbroic pegmatites showing mineral growth perpendicular to contacts. Compositional layering may be primary.

Small cut in megacrystic granitic gneiss on east side of highway.

Begin half-mile of road cuts
Begin half-mile of road cuts exhibiting intrusion of quartzo-feldspathic gneisses by members of the anorthositic gabbro suite, several phases of which appear to be present and in cross-cutting relationships. Source metasedimentary areas may be xenoliths. Pods of megacrystic gneiss may be anatectic in origin.

Kennels Pond -Avery's Fishing Site

Lake Catherine to east of highway
Lake Catherine to east of highway; metasediments intruded by anorthositic gabbros in road cut on west.

Steeply dipping kinzigites with white, anatectic layers.

Anorthositic gabbros intrusive into kinzigites
On west side of highway at sharp bend are excellent examples of anorthositic gabbros intrusive into kinzigites. The gabbroic rock transect the principal foliation (Fl) and are folded by upright folds of the F2 event.

Extremely garnetiferous kinzigites.
Extremely garnetiferous kinzigites. Here the rocks dip gently to the north due to the presence of a mesoscopic F2 synform.

Kinzigite in Rooster Hill Fm.

STOP 6. North end of Stoner Lake.
Type locality of Rooster Hill Fm. The Rooster Hill Formation is characteristic of a wide spread lithology throughout the Adirondacks. Its most characteristic feature is the presence of striking 1-4" megacrysts of K-feldspar. These are almost always flattened within the plane of foliation. Nonetheless, a number of these megacrysts preserve evidence of approximately euhedral crystal outline.
Compositionally the Rooster Hill megacrystic gneisses consist of orthopyroxene, garnet, hornblende. biotite, perthitic microcline, some plagioclase (oligoclase), and quartz. An igneous analogue would be quartz monzonite.
The parentage of the Rooster Hill megacrystic gneisses is obscure. It is not known Whether the megacrysts are phenocrysts or porphyroblasts. The fact these lithologies are conformable with the enclosing stratigraphy over broad areas is consistent with a metastratified origin but does not rule out intrusion as sills. The lack of substantial banding across units thousands of feet thick is less consistent with a metasedimentary origin than with an igneous one. However, the problem remains unresolved and requires further research.
Regardless of parentage, the Rooster Hill Fm. appears to correlate with the Lake Durant.

Contact of Rooster Hill and Peck Lake Fms.
Crossing contact of Rooster Hill Fm. and kinzigites of the Peck Lake Fm. Near the contact the Rooster Hill megacrystic gneisses become equigranular. This is probably due to cataclasis.

Kinzigites in the Peck Lake Fm.

Small road cut of kinzigite.

Canada Lake Store and Post Office
Canada Lake Store and Post Office. Ledges on north side of highway consist of pyroxene-quartz-plagioclase gneisses (enderbites) assigned to Royal Mt. member of the Green Lake Fm. Scarce amphibolite layers are boudinaged, and near east end of the outcrop amphibolite pods have been broken and rotated by intrusive material. This material is of the same pyroxene-quartz-plagioclase composition as the enderbite and grades into it.

Crossing Green Lake on Rt. 10-29A.
At east end of bridge and in woods are exposures of quartzites and leucogneisses of the Green Lake Fm.

Cross contact into charnockites of the Canada Lake Fm.
Cross contact into charnockites of the Canada Lake Fm. These form large road cuts along the highway.

Stop 7. Irving Pond Fm. in the Core of the Canada Lake Nappe.
The units to be examined occur along the east side of the road.
The Irving Pond Fm. consists of some 2500' of quartzite and less abundant quartzo-feldspathic gneisses and calc-silicates. It has been folded back on itself in the core of the nappe, and its apparent thickness is therefore doubled. At this particular locality we will examine the Irving Pond near its lower contact with the Canada Lake Fm. In the outer 100-200' near this contact the Irving Pond becomes "dirty" and clean massive quartzites give way to garnetiferous biotite-quartz-feldspar gneisses (kinzigites). Both of these lithologies are well developed at this locality. Also present near the contact is an excellent set of F1 minor folds showing axial plane foliation. These folds do not appear to fold an earlier tectonic foliation. Their axes parallel the Canada Lake Nappe.

Royal Mt. Member of the Green Lake Fm.
Enderbites and related gneisses of the Royal Mt. Member of the Green Lake Fm. The repetition of stratigraphy from the Canada Lake Store is due to recumbent, isoclinal folding about the Canada Lake Nappe.

Stop 8 -The Peck Lake Formation.
Road cut of garnetiferous quartz-biotite-oligoclase gneiss with minor amphibolite and calc-silicate bands. These gneisses are the dominant lithology of the Peck Lake formation which is exposed here on the south limb of the F1 fold. Needles of sillimanite can be seen in some specimens. White porphyroblasts are K-feldspars and pods of white quartzo-feldspathic material are probably anatectic .
In a little overhang near ground level there is an F2 minor fold with an axial trend of N50W. plunging 15 SE. Axial plane cleavage and lineation cut across the compositional layering and earlier foliation of this fold. It appears that such folding and cleavage are prevalent throughout outcrops of Peck Lake gneiss. Often these features are obscured by poorly developed compositional banding. Polishing and staining reveal both folds and cleavage in many specimens and. therefore, suggest that their abundance vastly exceeds their recognition.
The entire outcrop is a "large minor" fold. Note the change of dip from one end to the other. The accompanying equal area plot is for poles of foliation in this road cut and in outcrops directly NE of the road.
The lithologies and structures represented in this cut are typical of the Peck Lake formation. It is the structural complexities that make the Peck Lake formation difficult to work with and subdivide. It is, by far, the least competent unit in the sequence.

A11: MINERALOGY AND GEOLOGY OF THE NEWCOMB AND SANFORD LAKE AREA
BY
M. Ira Dubins
Department of Earth Science
State University College at Oneonta, New York
For many years the titaniferous magnetite ores of the Lake Sanford District constituted the largest source of titanium in the world. Today these deposits still rank among the world's greatest operative titanium ores. They are located within the Marcy metanorthosite massif. Within the field trip area adjoining metamorphosed rocks, especially the Grenville marble, provide interesting and diversified contrasts in mineral content and pose challenging problems as to formation and origin.

STOP 1. Tahawus NL Industries
The trip from Oneonta will take about 4 hours and 15 minutes. We will meet at the mine at 11:00 a.m. Our leader for this part of the field trip will be Stanford O. Gross of NL Industries, resident Geologist and Mining Engineer. We will be here until 1:00 p.m. You will have an opportunity to collect at the Mineral Collecting Area until about 1:30 p.m.

Marble outcrops on east side of parking lot; massive, grayish-white calcitic; portions stained a light yellow-brown; Present are, graphite, calcite, and in small grains pyrrhotite, garnet, and sphene.

Well rounded boulders, cobbles, and pebbles of metanorthosite, gneisses, and other rocks in the area occur in this fiuvioglacial deposit along with sand.

On both sides of the highway are large outcrops or amphibolite weathered a deep brown. A fresh surface is medium-grained grayish-brown with nodules of hornblende scattered throughout the medium-grained material. Some of the amphibolite has a pinkish tint when there is more garnet present. Also present are biotite, garnet, plagioclase feldspar, and quartz. Some of the amphibolite nodules have been elongated producing a gneissic appearance. Some of the amphibolite has been intruded by numerous dolomite veins less than 2mm wide.

STOP 5. Parking area on right.
Sign reads Trail to Irishtown via Minerva Stream and Lester Dam. On both sides of road extensive outcrops of garnetiferous gneiss. Occasional magnetite present with some hornblende and pyroxene. Some gabbro is also present in which magnetite and ilmenite are abundant.

STOP 6. On left is garnetiferous gneiss with some magnetite.

On left gabbro with garnet, pyroxene, very small amounts of magnetite and ilmenite with plagioclase feldspar as metacrysts. Gabbro is lighter than stop 5 occurrence.

Metanorthosite outcrops, weathered and fresh medium-grained; weathered metanorthosite is white and fresh surface is dark gray.

On left outcrop of coarse-grained metanorthosite. Phenocrysts are much larger than in previous outcrop.

B7: KARST GEOMORPHOLOGY OF THE COBLESKILL AREA, SCHOHARIE COUNTY, N.Y.
John E. Mylroie
Murray State University
Murray, Ky.
Arthur N. Palmer
State University College
Oneonta, N. Y.
The term "karst" refers to a landscape that has evolved primarily by the solutional weathering of bedrock. Karst landscapes, dominated by features such as sinkholes, caves, and cave springs, are most commonly found where calcareous rocks, particularly limestone, comprise a large percentage of the surface.
The Cobleskill area of east-central New York State (Figure 1) is a portion of the Helderberg Plateau, the very northeastern tip of the Appalachian Plateaus geomorphic province. This area contains limestones of Helderbergian (Lower Devonian) age, dipping 1-2 degrees to the south-southwest. Northeast of the village of Cobleskill (Figure 2). tributaries of the north-flowing Schoharie Creek have entrenched through the limestones, providing paths for ground water flow sufficient for caves and other karst features to have developed to an extent seen nowhere else in the Northeast. Recent works by Kasteing (1975), Baker (1976), M. V. Palmer (1976) and Mylroie (1977) have provided a detailed geomorphic and hydrologic examination of the karst in this area. To the layman, the area is known chiefly as the location of Howe Caverns, which is part of the largest underground drainage system in the state.
The stratigraphy of the region is shown in Table 1. A thick sequence of Ordovician clastic rocks are overlain by a thin Upper Silurian section consisting of the Brayman Shale, Cobleskill Limestone, and the lower beds of the Rondout Dolomite. The Silurian-Devonian boundary is transitional within the Rondout Dolomite in this locality (Rickard, 1915). The Helderberg Group of early Devonian age consists of the upper beds at the Rondout Dolomite and the Manlius, Coeymans, Kalkberg, New Scotland and Becraft Limestones. All the limestones except the New Scotland are rather pure, with the Coeymans, Kalkberg and Becraft being exceptionally good scarp and bench formers. Overlying the Helderberg Group is the Tristates Group, a section of Lower Devonian clastic rocks grading upward to the Middle Devonian Onondaga Limestone. The Onondaga is a cherty, resistant limestone that also forms benches and scarps. It is overlain by the Middle Devonian Hamilton Group, composed primarily of clastic rocks which include the youngest bedrock units of the Cobleskill area.
Karst features are well developed on the Helderberg limestones, particularly the Manlius, Coeymans, and Becraft. Although karst features are common in the Onondaga Limestone farther east, this rock unit is not exposed over a broad enough surface in the field trip area to possess significant karst features.
A variety of Pleistocene glacial sediments overlie the bedrock in discontinuous and irregular patches, primarily in the form of till sheets and drumlins. Glacio-alluvial sands and gravels are common in the valleys, as are lacustrine clays related to glacial Lake Schoharie. (LaFleur, 1969). Holocene sediments consist mostly of reworked glacial
material and colluvial material derived from the Paleozoic rocks .
As with any geologic field trip, many of the features to be viewed are on private lands. It is important, therefore, to follow instructions exactly and to exercise a high degree of consideration and conservation at each locality. Detailed instructions are given here and in the road log as to where to go and where not to go at each stop; please obey them. <

STOP 1. Physiography of the Cobleskill area.
From this location, the general physiography of the Cobleskill Plateau can be seen. Cobleskill Creek. the major surface stream of the area, flows eastward immediately below (north of) Stop 1. Further to the north lies the gently rolling Cobleskill Plateau, comprised mainly of Helderbergian limestones, its landscape morphology controlled both by glacial and by karst processes. The regional dip is 1-2 degrees SSW. South of Stop 1, the limestones disappear beneath Middle Devonian rocks, mainly of clastic lithology. To the northwest is a prominent flat-topped hill, Barrack Zourie, which is an outlier of the Middle Devonian rocks. North of the Cobleskill Plateau lies the Mohawk lowland, developed on pre-Silurian rocks. Looking eastward along Route 7, three major structural benches can be seen on the right (south). These benches are formed on resistant limestones and are not erosional terraces. The lowest one is formed on the Coeymans Limestone, the middle one on the Becraft Limestone, and the upper one on the Onondaga Limestone. The corresponding benches to the north of Route 7, across Cobleskill Creek, are for the most part obscured by thick deposits of glacial drift.

Note drumlins to the west, resistant limestone benches to the east.

STOP 2 --Cobleskill Creek
Cobleskill Creek, seen here, is the master surface stream of the area. Glacial deposits of Wisconsinan (and possibly earlier) age have displaced the creek from its pre-glacially entrenched-valley onto the bedrock benches that form the south bank of the buried bedrock valley. Glacial till now forms the north bank, and attains thicknesses of more than 100 feet in the pre-glacial valley. Looking downstream, the post-glacial superposition of Cobleskill Creek on the Helderbergian limestones can be seen. The south-southwesterly dip of the beds may have counteracted the tendency of the creek to shift back into its original sediment-filled valley. Part of the flow of Cobleskill Creek sinks into solutional openings in the south bank, at the point where the Cobleskill Creek first crosses onto the limestones, just west of the bridge. The water resurges 6000 feet downstream where the creek swings north and leaves the limestones. During low flow, this underground diversion route is capable of accepting the entire flow of the creek, so that the channel is left dry for the next 6000 feet. This subsurface diversion of a surface river is one of the longest in the Northeastern United States.

Notice drumlins ahead and
to left.

STOP 3 --Doc Shaul's Spring
To the south of the intersection is Doc Shaul's Spring, a large artesian karst spring (Figure 5). This spring is located directly above the glacially buried northern bedrock bank of the pre-glacial Cobleskill valley and drains solution conduits in the Rondout, Manlius, and Coeymans Formations. When the bedrock valley was filled with glacial sediment, a resurgence located in the valley wall at this locality was buried. In response, the underground water piped a conduit upward through the glacial sediment to the surface following the retreat of the east glacial ice sheet. This artesian spring, with a peak discharge of more than 40 cfs, is one of the largest karst springs in the Northeast. It drains several square miles of the Cobleskill Plateau to the north, including the areas seen at stops 4 and 5 (see Figure 4). The elongate hill south of the spring is a drumlin lying along the axis of the buried pre-glacial valley of Cobleskill Creek. To the north of the spring is a steep hillside formed by the till-covered Becraft and Onondaga structural benches. No bedrock outcrop is known within a radius of more than 1500 feet in any direction from the spring.

STOP 4. Limestone pavements.
Along the east and west side of the road at this location are exposed bedrock surfaces developed along bedding planes in the Becraft Limestone. Bare surfaces of this type are called limestone pavements. In jointed limestones, such as those seen here, the joints become solutionally enlarged by infiltrating water to form fissures called grikes. Where the grikes intersect to form a checkerboard pattern, the blocks of limestone bounded by the grikes are called clints (Sweeting, 1973). In thick-bedded rocks such as these, the Joints (and therefore the grikes) tend to be widely spaced (about 3 to 30 feet apart) I and the resulting clints are large and are stable with respect to mechanical weathering. In a thin-bedded limestone, such as the Manlius, the joints and grikes are very closely spaced (about 3 inches to 3 feet apart), resulting in small, unstable clints that are easily rotated by mechanical weathering to form a chaotic, unstable surface. Rainfall on a large area of limestone pavement insurges in a diffuse manner along the grikes, so that no surface streams can form. Also note the relative resistance of the Becraft fossils to weathering.

Pass Runkle Cave --its resurgence can be seen across the field to the left (west)

STOP 5 --McFail's Hole area: groundwater insurgences, sinkholes, pits.
Follow the field road from the highway down and around the farmer's field and follow the path into the woodlot below. The features seen here are confluent groundwater insurgences that contribute water to Doc Shaul's Spring (Stop 3). Most of them are vertical shafts formed by the solutional enlargement of joints in the upper formations of the Helderberg Group (Figure 6). They are named for some of the original explorers who descended the pits in search of caves.
A large number of insurgences are closely clustered in this area. This clustering is caused by two phenomena:
a) The area is a window of limestone in the surrounding clastic and glacial cover. Limestone is exposed to solutional processes from water draining off the surrounding impermeable uplands. The streams flow radially into the area and sink in a number of separate insurgences that all unite in the subsurface along a single drainage path.
b) The large amount of recharge available from the impermeable catchment area, plus the large sediment load carried in from that area, has blocked many of the insurgences, causing the formation of overflow routes to secondary insurgences, which further increases the complexity of the insurgence pattern.
Note: Permission to enter this property must be obtained from the National Speleological Society, 1 Cave Avenue, Huntsville, Alabama 35810. Visitors must be accompanied by a local member of the N.S.S.
Referring to Figure 7. locate and examine each of the features discussed below.
1. Wick's Hole - a large, occluded insurgence receiving the combined flow of three intermittent streams that unite here. The bedrock exposed in the walls of the sinkhole is the Kalkberg Limestone. Note the washed-in vegetal matter and sediment, and the overflow route to the south.
2. McFail's Hole - a large pit insurgence formed by solutionally enlarged joints (Figure 6). It overlies directly the cave passage that drains this area. Formerly 90 feet deep, its lower 30 feet has become blocked in recent years by collapse material. The upper lip of the pit is in the Kalkberg Limestone, and the main part of the shaft is in the Coeymans Limestone.
3. Ack's Shaft - a pit insurgence 80 feet deep. It is narrower than nearby McFail's Hole, although it receives about the same flow of water. The water that utilizes this pit enters a small insurgence 200 feet to the northwest and flows to Ack's Shack through a shallow solution conduit about 10 feet below the surface. The water enters the wall of the pit near the top and descends to a narrow cave passage below. The top of the pit is an intersection feature, caused by the collapse of the 10 feet of rock directly over the pit. The upper part of the pit is formed in the Kalkberg Limestone, the lower part in the Coeymans and upper Manlius Limestones.
4. Cave Disappointment - a pit insurgence similar to McFall's Hole, fed by a perennial surface stream. This pit leads to a series of adjacent shafts, fissures, and low cave passages. The pit connects by way of these tributary routes to nearby Hanor's Cave. The pit is formed in the Kalkberg and Coeymans Limestones.
5. Hanor's Cave - an overflow pit insurgence for floodwater overflowing from Wick's Hole. Hanor's Cave transmits this water to Cave Disappointment. The cave, developed in the Kalkberg and Coeymans Limestones, fills to the ceiling with water during floods.
6. Walking north up the stream bed that feeds Hanor's Cave, note the solutional enlargement of joints in the exposed bedrock. Continue north to Wick's Hole, then follow the path around the field to the vehicles.

STOP 6 --Howe Cave Quarry.
Stop along the road at the northeastern edge of the quarry. The Coeymans Limestone is exposed in the ditch on the west side of the road. Glacial striae can be seen on the rock surface, presently undergoing destruction by solution. Solutional denudation rates as much as a foot per 1000 years are common in karst areas (Sweeting, 1973). Cross the ditch (to the west) and climb to the top of the dirt ridge but no farther, and look down into the quarry. The quarry floor is located within the lower Manlius Limestone, and the quarry walls are formed by the middle and upper Manlius Limestone and the Coeymans Limestone. Note the thin bedding of the Manlius, compared to the thick bedding of the overlying Coeymans. On the far west wall of the quarry is a low-angle reverse fault (dipping 14 degrees south, striking N750W) with approximately 1.5 feet of displacement (Figure 8). It is subsidiary to a larger bedding-plane thrust located below the quarry floors, best seen within the natural-cement mine located beneath the quarry, which contains large gash veins of strontium and barium minerals (40 feet long, 3 feet wide, and 8 feet high) associated with the faulting. Many of the joints near the top of the quarry wall are solutionally enlarged but become narrower with depth. The Howe Caverns master cave once crossed the area now occupied by the quarry, from west-northwest to east-southeast, but has been truncated by the quarrying operations. The western section of the cave extends through the salient of limestone that juts into the quarry from the west wall. The actual cave opening, located along the northeast wall of this salient, is obscured by quarry debris, as is the corresponding opening in the eastern wall of the quarry. A drainage tunnel has been dug into the cave from the south side of the salient, draining the cave water across the quarry floor to an artificial shaft in the middle of the quarry, which carries the water into the cement mine below.

STOP 7 Gravity springs and openings to cement mine.
Park just west of the small bridge over the stream. At the bridge, look upstream at two grated openings, one rectangular and the other rounded in cross section. (Do not attempt to enter any of the features described in this stop; view from shoulder of road only.) This is the resurgence point for the water in Howe Caverns that was seen to flow across the quarry floor at Stop 6. These openings apparently represent the original, natural solutional resurgence for Howe Caverns, now altered by mining. The bedrock ledges exposed are the Rondout Dolomite, which has been mined as a "natural cement" (Cook, 1906). The Rondout contains the Silurian-Devonian boundary in this part of New York State (Rickard, 1975). Proceding downhill (west), two more rectangular openings are seen. These also are openings to a cement mine in the Rondout. Farther downhill, the small ledge of thick-bedded rock is the type section of the Cobleskill Limestone. About 9 feet of Cobleskill Limestone occurs here, overlain by the Rondout Dolomite and underlain by the Brayman Shale.
Farther down the road on the north side is a small resurgence, Nameless Spring, a gravity spring in the Cobleskill Limestone (Figure 9). This spring has been dammed as a water supply. The small erosional re-entrant in the valley wall where the spring emerges is called a spring alcove. Immediately west of Nameless Spring is Nameless Spring Cave, an overflow spring for Nameless Spring. This cave is developed at the Rondout/Cobleskill contact and carries water only in flood times. Because of the larger spring alcove at the cave, it is possible that Nameless Spring is a fairly recent tap off from Nameless Spring Cave.

STOP 8 --Howe Caverns.
Park at the Hove Caverns parking lot and enter the lodge as a group. If the party is sufficiently large, it is possible to be admitted to the cave at the half-price group rate. (Advance notice must be given in order to receive group rates.)
In the following discussion, refer to Figure 11 for locations and place names in Howe Caverns. The elevators into Howe Caverns occupy an artificial shaft to the cave. The original entrance is located immediately southeast of the quarry seen at Stop 6. The elevators descend roughly 160 feet to the cave. Howe Caverns consists of a large master cave passage flowing southeast nearly parallel to the regional strike, with water contributed by dip-oriented tributary passages that enter from the north. Leaving the elevator, an abandoned passage (the West Passage) is seen to the left through the concrete portal. Although it once drained much of the Cobleskill Plateau farther west, it no longer carries a stream. It is terminated after a few hundred feet by collapse where it approaches the wall of a surface valley. This passage apparently formed prior to the incision of the valley that now truncates it. Straight ahead from the elevators is a natural chamber with an artificial tunnel heading north from it. This tunnel connects to the rear of the Winding Way and was constructed to provide a loop passage for smoother flow of tourist traffic. The tour follows the natural cave passage to a major junction. To the left, in the floor, a stream enters and follows the main cave to the southeast. Ahead and to the left is the entrance to a long tributary passage, the Winding Way, which will be discussed in detail later. The tour follows the main passage to the right. This passage is a large conduit composed of two basic parts: a large oval tube, 20 to 30 feet wide and 15 to 20 feet high, with a deep canyon cut in its floor, 6 to 12 feet wide and 10 to 15 feet deep, formed by entrenchment of the cave stream beneath the tube level (see Figure 10). The solutional ceiling is located at the Coeymans/Manlius contact, and the cave passage is located in the Manlius Limestone. The ceiling rises above the Coeymans/Manlius contact only in areas where ceiling collapse has occurred. Note the difference between the smoothly sculptured solutional ceilings and the rough, planar ceilings produced by collapse. The cave continues downstream over a bridge and past a large collapse area to the largest chamber in the cave, known as Titan's Temple. In this chamber, evidence for each stage of the cave's origin can be seen. The passage originated as a solution conduit along the Coeymans/Manlius contact and was eventually enlarged by solution into the large tube with elliptical cross section now seen as the upper half of the main passage. At some point in the past, probably in response to a drop in the level of Cobleskill Creek, the cave stream cut downward to a lower level, forming a new passage that emerged from the upper tubular level. The upper level is terminated by sediment fill a short distance to the east of Titan's Temple. Upstream from the divergence point, the cave stream entrenched the deep canyon in the floor of the tube. At the point of divergence between the two levels, a reverse fault cuts through the cave having a dip of 14 degrees to the south-southwest. This is the same fault observed in the quarry wall at Stop 6. The cave water followed the dip of the fault plane to the south in its divergence from the upper level. The fault appears to have no further impact on the cave (Gregg, 1974).
Downstream from Titan's Temple in the lower, active level, the cave passage is generally rectangular or arched in cross-section. The rectangular areas occur where the thin-bedded and highly jointed Manlius Limestone has collapsed along bedding planes, destroying the curvilinear shape of the passage. Joints contribute small amounts of infiltrating water through the ceiling in this part of the passage, forming many stalactites aligned in rows along the joints.
A few small side passages enter this section of the cave. They are of two basic types: abandoned upper levels or loops of the main passage, and abandoned or active tributary passages. Nearly all the tributaries enter from the north, feeding water to the master cave from insurgence areas located in the up-dip direction.
The cave stream is ponded midway in the main passage, forming the "Lake of Venus" and causing alluviation of the bedrock floor. The boat ride on the lake demonstrates some of the explorational difficulties found in caves that are partially flooded. The Lake of Venus has been artificially deepened by the construction of a small dam at the end of the tourist route.
Returning along the main passage, the tour then enters the Winding Way. Although it is normally dry, water pours out of this passage into the main stream during floods. The Winding Way is a classic example of what is called a canyon passage, high and narrow with many twists and turns. As the passage is followed up-dip, the ceiling gradually ascends. The upper part meanders back and forth over the lower level of the canyon. The ceiling of the Winding Way cuts discordantly downward across the strata to merge in a graded manner with the solutional ceiling of the master cave. The discordant ceiling results from the transmission of water to the master conduit from stratigraphically higher insurgences.
The artificial tunnel branching from the Winding Way leads the tour back to the elevators. Notice the obvious difference between the solutional walls of the Winding Way and the blasted walls of the tunnel. Near its southern end, the tunnel intersects a large natural chamber. Along the east (left) wall of this room are some interesting calcite deposits (informally called "lilypads"). They mark the former water surface of a stagnant pool of water that was supersaturated with respect to calcite. Several different pool levels can be discerned, and some dogtooth spar is visible in places below the levels of the former water surfaces. Also along the east wall of this room is a solutionally enlarged fissure, 40 feet high, that extends nearly to the surface. This fissure is a source for the mud, water, collapse material, and glacial debris seen at this location. Cross the bridge, enter the elevator, and return to the surface.

B8: SEDIMENTOLOGY AND PALEONTOLOGY OF PORTIONS OF THE HAMILTON GROUP IN CENTRAL NEW YORK
Bruce Selleck
Hamilton, NY
Richard Hall
University of North Carolina Chapel Hill, NC
The richly fossiliferous marine sedimentary rocks of the Middle Devonian Hamilton Group of Central and Western New York (fig. 1) have been the object of paleontologic, sedimentologic and stratigraphic studies for nearly 150 years. The purpose of this field trip is to introduce participants to various lithofacies and faunal assemblages which characterize the upper portion of the Hamilton Group in the area of its type section. We further hope that observation and discussion of sedimentary structures, lithologies and fossil occurrences in field exposures will illustrate the excitement and frustration inherent in paleoenvironmental interpretation.

STOP 1. Colgate Quarry
Chenango Sandstone (Upper Skaneateles Formation)
Remarks: Most of the buildings of Colgate University are constructed of the thin-to medium-bedded, fine grained Chenango sandstone (= Colgate sandstone of Cooper, 1930) exposed here. A series of nearly perpendicular vertical joints made quarrying a rather simple process.
Noteworthy feature, here are the large slump structures in the lower portion of the exposure. The fauna is largely dominated by Tropidoleptus, Mucrospirifer and numerous epifaunal and semi-infaunal bivalves. The asterozoan Devonaster has been reported, but is quite rare.

STOP 2. Briggs Road Quarry
Upper portion of Ludlowville Formation.
Height range
Lithology
Fauna
11.7' - 16.1'
Green-gray micaceous laminated siltstone with interbeds of gray calcareous shale.
Epifaunal F.F.
78%
Infaunal F.F.
Infaunal D.F.
Vagrant H.+C.
Turbid Int. F.F.
6.4' - 11.7'
Gray silty shale with 1-3" thick beds of laminated and rippled siltstone.
0 - 6.4'
Gray micaceous siltstone
Dominant Genera
Upper siltstone:
Ambocoelia
Spinocyrtia
Elita
Nuculoidea
|
Middle shale:
Chonetes
Lower siltstone:
Devonochonetes
Tropidoleptus
Mucrospirifer

STOP 3. Geer Road Quarry
Upper portion of Ludlowville Formation.
Remarks: This quarry provides an opportunity to observe and contrast the two types of coquinites which are characteristic of the Hamilton in this region. Approximately 2.1 feet from the base of the section a phosphate nodule-bearing coquinite is exposed. A similar bed is present at 14.2 feet. Other (storm lag ?) coquinites are scattered throughout the section, especially from 15.5 to 20 feet in the section.
Height range
Lithology
Fauna
17.0' - 23.0'
Crumbly to fissile gray shale.
Chonetes and Ambocoelia dominant
Gray silty shale with light brown laminated and rippled thin beds of siltstone
Dark gray fissile silty shale grading upward into crumbly dark gray shale.
0 - 1.9'
Dark brown silty calcareous shale.
Bivalves abundant

STOP 4. Pierceville Quarry
Ludlowville Formation.
Height range
Lithology
Fauna
Dark gray to brown shaley siltstone. Occasional rippled siltstone beds.
Various infaunal and epifaunal bivalves.
15.0'
Gray calcareous shale
<i>Spinocyrtia</i> dominant
0 - 15.0'
Crumbly to fissile dark gray shale
<i>Chonetes</i> dominant.
Remarks: Three major lithofacies/biofacies are exposed at this stop. A Chonetes-bearing dark shale, a Spinocyrtia-bearing grey shale and a bivalve-bearing siltstone. The patchy distribution of the Chonetes in the lower section of the quarry was described by Linsley, et al. (1972). Strips and patches of Chonetes on bedding surfaces were ascribed to areas of grass-covered and grass-free sediment. Coquinites with broken and abraded shells were thought to be storm lag deposits. The uppermost portion of the quarry is a siltstone with abundant bivalves. Apparently higher rates of deposition and shifting substrates precluded the domination of the sessile epifaunal articulate brachiopods.

STOP 5. East Hill Road - Georgetown
Moscow-Tully Contact.
Remarks: The silty shales and siltstones of the uppermost Moscow Formation are seen here overlain by the Upper Devonian Tully Formation. The Moscow here is dominated by large articulate brachiopods and bivalves, with numerous, well-preserved trilobites, particularly Phacops.
The contact is placed at the base of the first thin blue-grey limestone. Several thin (2-6") beds of limestone, separated by calcareous siltstone, characterize the Tully here. The Tully at this location is rather sparsely fossiliferous, with a few solitary argose corals and the colonial Favosites most prevalent. Hypothyridina, the diagnostic Upper Devonian Rhynconellid, has been reported in the Tully here, but is quite uncommon.

STOP 6. Deep Spring Road Quarry
Moscow Formation.
23' - 38'
Fissile dark gray silty shale. Occasional thin siltstone beds. Prominent coquinite at 27'
Epifaunal F.F.
Infaunal F.F.
Infaunal D.F.
Vagrant H.+C.
Turbid Int. F.F.
Brown siltstone with ripple laminations and groove casts.
0 - 23'
Dark gray to light gray fissile slightly silty calcareous shale. Phosphate-bearing coquinite near base.
Dominant Genera
Upper shale:
Chonetes
Spinocyrtia
|
Middle siltstone:
Mucrospirifer
Paleoneilo
Lower shale:
Nuculoidea

B9: PHYSICAL AND BIO-STRATIGRAPHY OF THE ONONDAGA LIMESTONE IN OTSEGO COUNTY, NY
Richard Lindemann
Dept. of Geology
R.P.I. and Skidmore
Robert T. Simmonds
Earth Science Dept.
SUC, Oneonta
PURPOSE
The purpose of this article is to summarize the work which has been done on the Onondaga Limestone so as to provide a brief introduction, and a fairly comprehensive set of references for those who are curious about the formation. No startling new discoveries will be revealed. The Onondaga formation has been the subject of study by numerous of the immortals of New York State geology, by three doctoral students and at least five students at the master's level. These studies have provided a wealth of information on the formation which has not previously been compiled into a comprehensive summary other than those which are so concise as to provide nearly no information at all. At present numerous aspects of the formation are being studied at the industrial, governmental, and academic levels. We know of several studies in the academic sector alone which are so near completion as to necessitate the modification of this summary almost before it becomes available. "So it goes." Kurt Vonnegut. Jr. (1970B) INTRODUCTION The Onondaga Limestone has long been recognized in New York and is one of the state's most extensively exposed and prominent formations. Its outcrop and characteristic escarpments extend for over 550 km from Buffalo to the Helderbergs and thence southward through Kingston to Port Jervis (Fig. 1). This outcrop is dotted with hundreds of active and inactive quarries which have produced vast quantities or building stone and aggregate material. Since 1967, when the first large, subsurface, gas-bearing Onondaga "reef" was located, interest in the formation has waxed somewhat. Despite its prominence and economic import there is yet much to be learned about this formation, particularly in its more academic aspects. The Onondaga Formation is a coarse-to-fine-grained limestone, which ranges in thickness from 21.5 m (70') in central New York to in excess of 49 m (160') in the eastern and western parts of the state (Table 1). A variety of forms and colors of chert are common throughout. The formation was deposited during Eifielian time (lower Middle Devonian) (Rickard, 1975) just prior to and during the first clastic influx from the Acadian Orogeny. The Onondaga represents the last extensive carbonate and reef building phase in the region.

STOP 1.Uppermost Edgecliff - lowermost Nedrow Members
This exposure contains the uppermost Edgecliff and lowermost Nedrow Members. Though the contact cannot be seen, the pronounced differences in fauna and lithology are evident. Note the color and nature of the chert for future reference. The outcrop is typical of hundreds of other Onondaga exposures in extent and weathering characteristics.

STOP 2. Abandoned Quarry
Park in abandoned quarry entrance on left and walk up into quarry. In this quarry 57' of the formation are exposed; 19.5' Edgecliff, 12.5' Nedrow, 25' Moorehouse. The gradational beds between the Schoharie and Edgecliff can be seen in the road as you walk up into the quarry and in the pinnacle of rock to your left just as the road begins to level off on top. These beds grade from dark and glauconitic below into clean, coarse-grained, coraliferous Edgecliff above. The floor of the northern quarry section is in the transitional beds.
The western quarry section which we will visit has exposed the upper Edgecliff, the entire Nedrow, and the lower Moorehouse. The main floor of the quarry lies on the upper Edgecliff which can be recognized by its corals, large crinoid columnals, and pyrite. The water filled pit and ramp are entirely in the Edgecliff. The main quarry walls contain the dark, shaley Nedrow in their lower parts and the cherty Moorehouse above.

STOP 3. Mount Tom Reef No. 1.
The stop is the near (East) face of the knob directly ahead. Mount Tom Reef No. 1. This is the reef shown in Fig. 6 of the text. Study the reef zonation in the text before proceeding onto the reef. Exercise caution as much of the rock wall is unstable and footing can be tricky. The obvious characteristics of this and all other bioherms in the Onondaga, are its massively unbedded nature and lack of chert. With patience and close examination you will be able to spot the different corals which comprise the framework of the reef. Examination reveals that the clear cut zonation shown in Fig. 6 is not nearly so clear cut in the reef itself. The matrix material between the corals consists mostly of lime mud, with the coarse crinoidal material typical of many Onondaga bioherms lacking.

STOP 4. Reef is exposed in the S end of this hill.
Another reef is exposed in the southern end of this hill. The exposure appears to be the "Core Facies" of a reef, but its actual position within the reef is uncertain due to lack of exposure. The reef seems to extend a considerable distance on the basis of the topographic expression.

STOP 5. Mt. Tom Reef No.7.
The hill on the east side of the road is Mt. Tom Reef No.7.
Though it has been referred to as a bioherm. this hill is composed of bedded, cherty limestone: characteristics not found in biohermal structures. The fauna here is not typical of other bioherms or the "normal" Edgecliff. The fauna is dominated by small broken twigs of the branching tabulate Coenites and doesn't contain anything which could be considered a framework. At present the significance of these beds is uncertain.

STOP 6. Onondaga Formation
This exposure and its twin across the valley are two of the most continuous and complete exposures of the Onondaga Formation. Here the formation is exposed from its phosphoritic based transitional beds, through the shaley Nedrow, and into and including most of the cherty Moorehouse. For the thicknesses, fauna, and lithologies of the members refer to Figure and to the text. Figure 7 is provided to show member thicknesses here and at STOP 7 as well as the characteristics and continuity (or lack thereof) of chert bodies within the formation.

In many respects this set of exposures is quite similar to STOP 6. It is however significant in its continuity with STOP 6 and the differences between the two with respect to chert. This stop is further significant because it's the easternmost exposure of the Nedrow Member as defined in central N.Y., the Tioga bentonite, and the Seneca Member. The latter two are exposed a half mile east of the rest area and can be seen to lie on about two meters of nearly chert-free Moorehouse. East of the uppermost member of the Onondaga is the Moorehouse.

B10: THE PANTHER MOUNTAIN CIRCULAR STRUCTURE: A POSSIBLE BURIED METEORITE CRATER
Yngvar W. Isachsen
Stephen F. Wright
Robert J. Dineen
Geologic Survey, NY State Museum
(Published by permission of the Director, State Science Service, New York State Museum, Journal Series No. 236.)
Frank A. Revetta
State University College at Potsdam
We were led to a study of the Panther Mountain circular feature in the central Catskill Mountains, after discovering its striking appearance on satellite imagery. Our subsequent investigation to date does not permit us to explain the feature with any certainty, but it does enable us to narrow the range of possible explanations.
This article is a progress report which describes, in historical sequence, our investigations to date. Our work proceeded in the following, sometimes overlapping, stages: photogeology, gravity and magnetic measurements, conventional field study, and shallow seismic refraction profiling. A study of cuttings from a drill hole located inside the margin of the structure study is just beginning.
The structural geology of the region in which the feature occurs is not well known; the bedrock geology of the Phoenicia quadrangle, in which the Panther Mountain circular feature is located, has not been mapped in any detail. Chadwick (1936) shows a "preliminary map" of the Phoenicia and Kaaterskill quadrangles at very small scale (1:350,000), and the Geologic Map of New York by Fisher and others (1971) shows the geology only by projection. The formations shown on the State map, all continental clastic rocks of Upper Devonian age, are as follows: Walton Formation (shale, sandstone, conglomerate), which underlies the valley floor and most of Panther Mountain; the Slide Mountain Formation (sandstone, shale, conglomerate) which underlies the summit area, and the Honesdale Formation (sandstone, shale) which forms the summit itself. The colors of these rocks are red, green, and gray. The glacial geology of the region has been mapped and described by J.L. Rich (1934).

Edge of Gulf Course Road
Edge of Gulf Course Road between Rte. 28 and creek was the site of shallow seismic traverse. The seismic refraction data closest to the creek suggests a possible fracture zone in underlying bedrock. See text.

Large road cut and small quarry
Large road cut and small quarry on south side of road at first R.R. crossing on Rte. 28 since Big Indian. Many examples of joints typical of the Panther Mountain area can be seen.

N-S gravity and magnetic traverse.
Junction Rte. 28 and Rte. 42 at Shandaken, crossing point for N-S gravity and magnetic traverse. Traverse continued north along Rte. 42, and south via Fox Hollow and trail across the Panther Mountain structure and to the south

Shallow seismic refraction survey.
St. Vincent De Sales Cemetery. Gravel pit behind cemetery is site of another shallow seismic refraction survey. This seismic line essentially paralleled the valley. Interpretation showed bedrock to be unfractured.

Access to field trip stop is via a small, steep gravel road seen on the left as the highway takes a sharp left curve around a protruding kame. This rough access road switches back several times and passes a currently open gravel pit before reaching a large abandoned quarry. Total walking distance is slightly over one-fourth mile. This stop is included to display a series of well-developed joint faces in a large, fresh, man-made outcrop. These joints can be seen to be widely spaced, generally pervasive through this thick sandstone bed, and roughly planar in nature. Note the large amount of small-scale irregularities on even the largest and best developed joint faces. This is one of the many flagstone ("bluestone") quarries of the Catskill region which were operated in the early part of this century before being superseded by Portland Cement . It was quarries such as this which provided the old "sidewalks of New York".
"Indian Cave Quarry." Visible high on the slope through opening in trees on north side of road just opposite the junction of Rte. 28 and the Woodland Valley Road. The quarry was named locally for the cave-like nature of the holes created by the removal of red silty shale from beneath the overlying sandstone. We were not able to ascertain why the shale was mined, but its removal has allowed some shifting of the overlying sandstone blocks along joint planes. This allows easy observation of typical regional joint spacing (here about 3 m) in an outcrop near to, but not directly in, the rim valley.

Bridge over Esopus Creek heading up McKinley Hollow.
Small road to right crossing bridge over the Esopus Creek and heading up McKenley Hollow. The stream channel and broad alluvial flood plain are visible to the right. Downstream from this point, the stream meanders and braids across the valley. Nowhere in this area or further downstream is bedrock exposed in the stream channel.

Slide Mountain Inn
Slide Mountain Inn, located where small road branches west up the Bushkill Creek valley. The stream valley here is still deeply filled with alluvial sediments. Outcrop is limited to the very edge of the valley, where hillsides meet the valley floor. This intersection is also a station point on the E-W gravity and magnetic traverse of the Panther Mountain structure. Gravity stations are often located at road intersections or other well defined and surveyed locations to minimize error when correcting the gravity data.
The Slide Mountain Inn is typical of many Catskill summer resorts in the area, a number of which have catered to the summer tourist for over one hundred years. Access to the area was formerly via the railroad line from Kingston to Oneonta which was abandoned early in 1977. Passengers left the train at Phoenicia or Big Indian and were met by carriages from the particular resorts at which they planned to stay.

Stop at large pull-off on right side of road, often used by the county to store road stone and gravel. Walk .05 mile to small hollow where road crosses tributary of the Esopus Creek. Just beyond the stream, take a small unmarked trail to the right which leads immediately to the tributary.
In this lovely little glen the small feeder stream plunges down to Esopus Creek via a series of cataracts and spill pool. The jointing here is typical of jointing observed at most localities an or near the Panther Mountain structure even though this outcrop is located within 50 m of the Esopus Creek rim valley (which at this point is bottomed in alluvial gravels). Many joint surfaces can be seen, with strikes ranging between N63W and N78-83E. Note the lack of any dominant joint set traceable throughout the outcrop. Most joints are non-through-going, generally abutting other joint surfaces in either horizontal or vertical directions or both. Note also the characteristic lack of any consistent relationship between cross-bedding and the curvature of joint surfaces. The stream has greatly modified joint surfaces in its channel. Note also that this steep-walled stream channel has undergone a considerable amount of erosional unloading without any increase in joint density or other observable brittle deformation in the channel. Similar observations have also been made in the larger non-rim valleys of the area. In short, erosional unloading of valley floors has not, in itself, been found to cause an increase in joint density.

Look for an old brown house close to the left side of the road, and park where possible along the road margin. Exactly opposite this house, bushwhack directly down to the stream (about 50 m) and the outcrop shown in Figure 7B should be visible on the opposite (SSW) stream bank. Here, two sets of very closely spaced joints can be seen at stream level, one striking N2-9E and dipping 63° - 80°W and the other striking N30-34E and dipping 45°-56°SE. Joints in these sets are spaced from 50 cm apart to as little as 2 cm apart in a narrow (50 cm wide) zone in the outcrop. This outcrop of closely spaced jointing is very restricted in space. The jointing is not present in the thicker overlying sandstone nor in outcrops immediately up or down stream. Although joint spacing of about 1 m characterizes exposures present in the center of the rim valley, this outcrop and several others further downstream are the only ones observed in the entire Panther Mountain area which display this extremely dense jointing. Although outcrop control is limited, high-density fracturing appears to be the structural control on the arcuate pattern of Big Indian Hollow.

TURN AROUND HERE.
Bus or car turnaround. Small remnant of logging road on right just. beyond culvert. Turn around and go back down the valley towards Big Indian.

Bridge on Rte. 28 crosses Esopus Creek

A small field opens to the left. Walk down farm path which runs along the far edge of this field until the stream is reached, at about 200 m. The outcrop itself is a broad, flat exposure located on the opposite stream bank. In sone seasons it may be necessary to wade the stream, although a less detailed view can be had from the opposite bank.
Two closely spaced, planar, nearly orthogonal joint sets are exposed here (Fig. 7C, D). The N60-70E set is systematic (generally through-going in a strike direction and trends perpendicular to the stream course. Dips are mainly 68° -80°NW, but several are seen to dip 78°-80°SE. The N10•30W set is non-systematic. It trends parallel to the stream course and displays a range of dips suggestive of conjugate pairs. These dips generally have values of 60°-67° and 52°-76°SW though some are vertical. Joint spacing in both sets is consistently 30-50 cm and locally as little as 2 cm. Although we have found a general inverse relationship between bedding thickness and joint spacing, nowhere, regardless of bed thickness, have we seen such a display of closely spaced joints over this large an area.
This joint zone is limited in both horizontal and vertical extent. In the beds upstream, joint spacing increases to 1 m just above the waterfall. Similarly, joint spacing is 1 m or greater in the outcrop 20 m downstream and also in a large, thick-bedded outcrop located in woods 15 m southwest of the main exposure. At low water, joints in the N60-70E set can be seen to be only variably continuous into the underlying beds. This is another example where high-density joint zones seem to be restricted to certain beds in limited lateral positions along the rim. The significant fact is their restriction to the rim and, thus, their apparent control on stream development.
At the downstream end of this outcrop, jointing is extremely intensified in a narrow zone 40-50 cm wide, where the spacing is only 3-6 cm. This occurs within the N70-60E set. Note the resulting differential erosion between this zone and the remaining outcrop. Perhaps this illustrates, in microcosm, the way in which closely spaced joints control the circular rim valley that defines the Panther Mountain mass.

STOP 5. BEDELL STREET.
Small path crosses perpendicularly nearly the entire width of the valley. At this location and several others like it where the Esopus Valley is deeply filled with alluvial deposits. the shallow seismic refraction technique was used to search for zones of abnormal bedrock velocity. This is the site of our most definitive traverse. The near-level field provided an ideal test site where few corrections were needed, and the ease of access to the entire valley width was excellent. Interpretation of this traverse has identified a bedrock zone of low seismic velocity, which we interpret to be a continuation of the abnormally dense jointing mapped upstream. The seismic refraction method will be demonstrated here.

B11: GEOLOGICAL CONTEXTS OF ARCHEOLOGICAL SITES ON THE SUSQUEHANNA RIVER FLOOD PLAIN
Robert E. Funk
Anthropological Survey
New York State Museum
James T. Kirkland
University of Texas at Arlington
Bruce E. Rippeteau
State Historical Society of Colorado
Donald M. Lewis
Biological Survey
Published by permission of the Director, New York State Science Service, Journal Series No. 235. Prior to the present decade, prehistoric archeological research in New York State had a long history going back over 50 years, focussing on major drainage systems (Parker 1922; Ritchie 1938b, 1944, 1951, 1965 , 1969). Yet over this period relatively little attention was paid to the Upper Susquehanna Valley, including its major tributaries in the State. This neglect is surprising in view of the high archeological potential of the region, reflected in numerous recorded sites and surface collections, and a geographic position conducive to the study of many problems in cultural distribution and adaptation. The first major attempt at professional exploration occurred in the 1920's, when a canoe flotilla carrying archeologists and laborers began at Cooperstown and surveyed for archeological sites well down into Pennsylvania (Moorehead 1938). Later, surveys were conducted by William A. Ritchie, who also excavated some sites of the late prehistoric Masco culture (Ritchie 1934, 1938a, 1939, 1944:59-11, 1969:xxiv-xxvi). Sporadic work was carried out in the late 1960's by the New York State Museum and the State University at Binghamton, partly in connection with the State highway salvage archeology program (Wilcox n.d.a, n.d.b: Elliott and Lipe 1970; Funk and Hoagland 1972a, 1972b; Hesse 1968, 1971). A major interdisciplinary program of investigations into regional pre-history was initiated by the writer in 1971. Field work is expected to conclude with the 1977 field season and a final report will eventually be published. The project has involved personnel from several institutions, including the New York State Museum, the State University of New York at Albany, and the State University College at Oneonta. Preliminary reports have appeared (Funk, Rippeteau, and Houck 1973, 1974; Kirkland, et al 1976; Funk and Rippeteau 1977). The fundamental objective of this project is to delineate the history of human adaptations to the postglacial Upper Susquehanna environment. This requires the acquisition of data on the sequence of prehistoric Indian cultures, their distribution in time and space, their subsistence and settlement patterns, and the various components of environmental change. To accomplish these goals, our methodological emphasis has been on stratified flood plain sites, where the discrete occupation surfaces are separated by the accumulation of overbank sediments. In such contexts, the mixture of debris from different periods of habitation is minimal or absent; the patterning of artifacts, hearths, pits, or refuse on each floor is undisturbed; and radiocarbon dates on organic materials from these floors can be attributed to the individual occupations with a great deal of assurance. Thus it is possible to construct a well-dated stratigraphically based regional sequence of artifact styles and cultural complexes, to study within-site patterning, and to make valid between-site comparisons. Palynological data used to sketch a picture of floristic environments are acquired from bogs, occupation zones on archeological sites, or pre-cultural levels in our excavations. Other paleoenvironmental data are contributed through studies of changing postglacial landforms, especially with regard to the flood plain. When all the data are analyzed, we should be able to present a synthesis of prehistoric culture change in relation to environmental change within the Upper Susquehanna drainage. ACKNOWLEDGEMENTS Many persons have contributed to the Upper Susquehanna Project. We are especially indebted to P. Jay Fleischer for his input on the geology of several sites; to Beth Wellman for her assistance in preparing this report and the processing of collections acquired in our excavations; and to Franklin J. Hesse by whose efforts many of the sites were located and tested.

STOP 1. Fortin site, Locus 1 and Locus 2:
Located at the junction of the Susquehanna River and Charlotte Creek near Oneonta, the Fortin site loci yielded one of the most complete cultural sequences of any of the sites examined. At Locus 1 eight occupation zones and a plow zone were contained within 1.83 meters of stratified sands, silts, and small gravels. These deposits rested on compact gravels which appear to be of ice-contact derivation, perhaps reworked by the river. The deepest occupation level (Late Archaic, Lamoka phase) dates to 4185 ±120 years B P. (I-7098) and the youngest level just below plow zone (Early Woodland, Meadowood phase) is dated 3180 B.P. ±95 (I-6740).
At Locus 2, there were five occupation floors in 1.83 meters of unstructured silt, again resting on heavy gravels. In this case however the deepest zone only dates to about A.D. 200. The cultural components range from early Middle Woodland to Late Woodland in affiliation.
At both loci, occupations tended to concentrate on low rises which existed from the beginning (initially point bars?) and maintained themselves as perceptible topographic forms to the present.

STOP 2. Kuhr No.1 site
Located in Otego village at the junction of Flax Island Creek and the river, this site displayed a highly sensitive archeological stratigraphy. At least 11 living floors were present, separated by culturally sterile silt where the overbank deposits were thickest (3-4 m) close to the river. The oldest identified occupation, of the Lamoka culture, was dated at 4520 ±165 years (Dic-116). The field in which the site is located consists of four terrace-like long, low rises sub-parallel to the river. They occur in a south to north succession, with the highest being farthest from the river. The terrace presently adjoining the river is the youngest and presumably they increase in age away from the river, indicating successive positions of the river. The occupation levels occur mostly in the second terrace, and reach an average depth of 1.8 m. They trend upward onto the third terrace where they are compressed into the top .60 m of deposit, eventually feathering into the plow zone (upper 25 cm.).
A backhoe trench excavated to a depth of 4 m in the third terrace exposed 2.5 m of sterile silt below the deepest occupation level. At its base was the water tabIe. In turn this deposit rested on a coarse blue-gray sand at least 30 cm thick containing wood fragments, leaves, acorns, and pine cones. A wood sample yielded dates of 8970 ± 110 and 9020 &plusmin;85 years B.P. (Dic-113, 120). Test pits into sands and gravels 4 m below surface on the fourth terrace failed to yield organic remains.

STOP 3. Russ site
The archeological levels at this site overlie the Wells Bridge moraine on the north side of the river where it swings southward in the first leg of a crescentic bend. Here in some places .7 m of late-glacial lacustrine deposit overlie the moraine; in other parts of the field what appear to be river deposited sands rest atop the moraine. On the northeastern edge of the field 1.3 m of silts overlie the lake sediment and underlie a horizon dated 13,860 ±750-830 B.P. (Dic-7S0). These old silts may represent a very early stage of point-bar deposition, as they slope away to the south and west where younger silts have filled in following a slight southward shift of the river. This shift occurred at least 10,500 y.a. as indicated by a dated humic zone which caps the older sediment.
The more recent silts may be of overbank origin. By at least 8300 B.P. the first Archaic Indians occupied the site; the deepest living floors occurred at ca. 1 m. A terminus ante quem for the sub-plow zone silts is provided by dates on several hearths which extend below plow line from occupation surfaces destroyed by cultivation. These dates average about 4000 B.P. The plow zone itself contains artifact types ranging in age from 6000 y.a. to the present, so the silts immediately underlying the plow zone probably date to at least 6000 y.a.

STOP 4. Gardepe site
This site is located on the south side of the river near the middle of the bend. Since the river has moved slightly southward in postglacial time, it has added to the deposits on the north side, but has cut into the banks on the south side. An undetermined portion of an archeological site has been destroyed in this way.
The major locus of occupation closely parallels the river near its bank. Behind this locus and also paralleling the bank is a low rise. Farther from the river are other features associated with the moraine, including a fair-sized kettle hole bog only 100 m from the river. This bog, 7 m deep, was sampled by Michael Melia and the data incorporated in his Master's thesis.
Occupational remains occurred within six definable strata near the river bank. The upper two zones relate to modern cultivation and contain much mixed Indian material. Zone 3 was partly disturbed by plowing; below it the various levels were undisturbed. The artifacts and radiocarbon dates from Zone 1 through 5 suggest Indian occupations ranging in age from ca. 4000 y.a. to A.D. 1100. The mode of formation of Zones 4 and 5 is a mystery; flood deposition may have played a part but downslope wash from the adjoining rise also seems to be a factor. Zone 6, a firm olive-brown silt, was ca. 3 m thick, resting on bluish clays of possible lacustrine origin, which in turn covered the morainal deposit. Zone 6 seems continuous with old silts which overlie the moraine everywhere on the site, including the edges of the bog. Presumably therefore it is of fluvial origin but the precise mechanism is not fully understood. A bifurcated-base projectile point was recovered, apparently in place, about 40 cm below the top of the zone. Three m from the point a hearth within the zone produced charcoal dated 9380 B.P. ±100 years (Dic-261). The point is of a type dated ca. 8000 years old in the Southeast. Together with the dated hearth it suggests occupation by Early Archaic Indians concurrently with the late stages of formation of Zone 6.

B12: WEDGE-SHAPED STRUCTURES IN BEDROCK AND DRIFT, CENTRAL NEW YORK STATE
P. Jay Fleisher
SUNY, College at Oneonta
Wedge-shaped structures resembling ice-wedge casts and fossil ice veins have been found in both bedrock and drift hosts on the eastern Appalachian Plateau of central New York. These features are exposed in the walls of four separate borrow pits at three different localities within the upper Susquehanna River drainage, south of the Mohawk Valley and northwest of the Catskill Mountains. All three localities are within Otsego County and can be found on the Milford, Richfield Springs and Mt. Vision quadrangles. The index map of figure 1 illustrates the location of each site as well as their general topographic setting. Based on their respective locations they are referred to as the Crumhorn Mountain, Fitch-Metcalf, and Laurens-Mt. Vision sites.
The purpose of this paper is to review the physical characteristics and occurrences of these wedge structures and consider what, if any, paleoclimatic significance they hold. A review of the literature indicates that previous authors have reported many features in various parts of the northeast as being related to periglacial processes. The main question under consideration is whether the structures discussed here are in any way related to permafrost processes.
A variety of permafrost and frost related features have been reported for the New England area by Denny (1951), Kaye (1960), and Keteff (1961). The work of Denny (1936), Smith (1949, 1953), and Wolfe (1953) suggest the significance of periglacial processes that once occurred in Pennsylvania and New Jersey. Clark (1968) documented the occurrence of sorted patterned ground associated with quartzite ridges from Pennsylvania to Virginia and West Virginia. Small scale bedrock deformation (up-warps) flanking vertically tapered till wedges in central New York has been reported by Cadwell (1973), and similar features in the same general area were initially interpreted to be of potential periglacial significance by Fleisher and Sales (1971). Late Wisconsin ice-wedge polygons have been reported in south western Ontario by Morgan (1972). More recently, Walters (1975) suggested polygonal patterns associated with vertically tapered ground wedges in outwash of central New Jersey to be possible ice-wedge casts. While the suggested effects of alpine glaciers and associated climatic conditions as far south as western North Carolina have been subject to contested debate since first presented by Berkland and Raymond (1973), it seems clear that a growing body of field evidence from the northeast suggests that this region may have been subjected to periglacial paleoclimate conditions of variable intensity at some time during the late glacial chronology.

Impressive view of the Susquehanna Valley.
As the road climbs it provides an impressive view of the Susquehanna Valley.

Pull off to the right near the top of the hill in a bedrock quarry. The Town of Milford uses this rock for fill.
This is the Crumhorn Mountain Site. The quarry operation was much more active in the early 70's when more than a dozen wedge-shaped structures were exposed. Some have since been consumed by the operation or covered under colluvium, but two were well exposed in June, 1977. These can be found east of Boy Scout Road in the south facing wall of the excavation. They are most easily spotted by looking for the upward deformation of the siltstone bedding. Their deepest penetration has not been excavated, but judging from the amount of downward taper they are probably in excess of 2 m deep. These and all others occur along bedrock joints which seem to control their orientation.
Two sets of wooden pegs were emplaced in each of these wedges in order to determine whether their width varied seasonally due to temperature or moisture changes. The upper and lower portions of each wedge were monitored from April, 1976 to the present. The results are as follows:
Date | dist. between upper pegs | dist. between lower pegs
Wedge A (nearest the road)
Wedge B (farthest from road)
From these data it is concluded that no seasonal variation alters the width significantly.
The short upper segments of four other wedges may be detected through the colluvium along the east side of the road. Unfortunately, the most impressive wedge remains buried by debris along the south facing wall of the operation to the west of the road.
Most wedges are characterized by a highly compact filling that shows collapse foliation. However, a few small bedrock buckles can be found, in which little or no fill exists .
Ice-wedge casts or pop-ups seem to be the main question here.

Upper surface of a hanging delta
The planar surface on your right at the turn is the upper surface of a hanging delta that was built into glacial Lake Cooperstown which stood about 20 m above the modern Otsego Lake level.

STOP 2. Fitch-Metcalf Hill Site
Turn right just beyond large red barn onto Smith Cross Rd. (unmarked). Proceed for 0.2 miles to top of hill.
Pullover to the right, outcrop on the left. This is the Fitch-Metcalf Hill Site. There are two main wedges in this outcrop, but several others within walking distance up the road.
These wedges are similar in many respects to those on Crumhorn Mountain. They are comparable in size and filling, but associated bedrock deformation appears slightly different. Here the rock is somewhat more massive and less fissile, which may account for why the rock appears broken upward here, as opposed to flexed upward at STOP 1. Here too joints define the orientation of the wedges and the bedrock is veneered by a till that collapsed to contribute to the wedge filling.
Other much smaller wedges (or more accurately, buckles) can be seen in another excavation to the right (east). They can be reached by walking along the upper contour of the outcrop, through a raspberry patch and to a shallow excavation about 100 m away, or take the road if you're not a berry fan.
Once again we are left with the question of whether these features are frost related or simply reflect the adjustment that occurred due to glacial unloading.

STOP 3. Otsego County gravel excavation.
2014: The bridge is gone, so we took a bit of a detour to get here, and we'll adjust our route to the next stop...
This is the first of two locations, collectively referred to as the Laurens-Mt. Vision Site. At various times during the excavation of this deltaic feature (hanging delta or delta kame) massive gravel and sand foreset beds and poorly sorted topset gravels have been exposed. It is within the topset gravel that wedge-shaped structures have been observed. The largest reached a depth of 3 m and was 1 m wide at the top before being destroyed. Several smaller wedges have also been noted.
In each case the wedges show a vertical orientation in a general N-S trend. They are characterized by downward collapse that includes the flanking gravels. A pebble count taken here included about 95% local lithologies and less than 1% limestone. However, chert at 1.1% is also present. Since the chert originated in a limestone host, it is assumed that much of the carbonate that was present has been leached.
The lack of a polygonal wedge distribution rules out an ice-wedge mechanism for their formation. The evidence for leaching suggest that a soil-tongue forming process may have been active, but in other reported cases the carbonate content was much higher than would be anticipated here. This leaves the tension crack mechanism, which seems to have merit when one considers the juxtaposed location and trend of Otego Creek.

Pull off to the right and walk in to a shallow gravel operation 0.2 miles off highway. This is the second of two localities described as the Laurens-Mt. Vision Site. Repeatedly during the excavation of this site a variety of small wedges, similar to those at the last stop, and vein-like structure (thin wedges) have been exposed. It is assumed that the similarity of features, topographic setting and host material would dictate a similar origin for both localities.

GUIDEBOOK
SYRACUSE, NEW YORK
23-24 September 1978
Daniel F. Merriam, editor
It is appropriate that the Golden Anniversary meeting of the NYSGA be held at Syracuse University. Syracuse has been involved actively in Association activities since the beginning. As secretary, Harry N. Eaton of SU issued the announcement of the first meeting to be held at Hamilton College in April of 1925. He then was president the next year as Syracuse served as host.
In 1937 SU was host for the 13th meeting with Louis W. Ploger president. Again in 1950 Ploger served as president as Syracuse hosted the 22nd annual meeting on the Silver Anniversary of the formation of the Association (1925-1950). John J. Prucha organized the 36th meeting in 1964.
Syracuse is always proud and pleased to host the Association that may be the oldest organized state intercollegiate geological group in the country. The Association has grown considerably in size and stature from that first meeting 53 years ago (see paper by Lowe and Wolff on history of the Association in this volume). There is no record of the number of attendees but the meeting consisted of a few pages of handouts for the one field trip following a previous evening dinner and lecture. This loose organizational arrangement was successful in the early years and continued until 1953 when Kurt E. Lowe was elected first permanent secretary of the Association. The secretaryship provided a stability and continuity needed for the Association and beginning in 1956 guidebooks for each meeting were kept in print for sale. Lowe was followed in office by Philip Hewitt in 1968 (now the office was termed executive secretary), D.F. Merriam in 1972, and Fred Wolff in 1977. The Association affiliated with the American Association of Petroleum Geologists in 1974.
The Association grew in permanency and organization (it now had a constitution) so did the size of the guidebooks. From a few pages in 1925 to 425 pages in 1977. Subject matter was expanded until today the guidebooks provide one of the most important sources of information on the geology of New York State.
The offerings this year are no exception. In addition to write ups and roadlogs for the 17 trips, background papers on selected subjects are included. Of special importance are the two papers on the history of geology in New York by Don Fisher of the NY State Geology Survey and on the history of the Association by Kurt Lowe and Fred Wolff. These contributions undoubtedly will serve as standard references for years to come.
Each of the authors are to be thanked for their contribution. It is their collected efforts that made this publication possible. A different procedure was used this year on preparing the papers for inclusion in the guidebook. Each author was asked to provide finished copy for direct reproduction. Although this method has its problems (but all publication methods do), it allows authors greater flexibility and the possibility to make last minute changes. It also speeds up production time and reduces costs.
Many people have cooperated in putting on this meeting. Janice Patak assisted in typing, editing, and proofreading material for the guidebook and helped in a variety of other ways. Beverley O'Brien and Debby Blose also have assisted in preparing material and making arrangements. All of the faculty and students of the Department of Geology at SU have given considerable time and effort in preparing for the meeting. Credit for success of the meeting goes to the entire Department.
Dewey Hale of the Syracuse Chamber of Commerce provided material and advice in making arrangements. Owen Muir of the Treadway Inn helped with the housing. Elmer Foote of the SU press assisted with the printed material. Many individuals and other Departments at Syracuse University cooperated in the logistical arrangements.
Last but not least Fred Wolff lent his support for the entire year of preparations. This was most appreciated.
So here are the results for the golden anniversary volume. May the next 50 years of the Association be equally successful and rewarding to those involved and interested with the geology of New York State.
D.F. Merriam, President
Syracuse, NY 13210

A1: DEFORMATION STRUCTURES IN LOWER PALEOZOIC ROCKS, NORTHWESTERN NEW YORK
Brian G. Barber and John T. Bursnall
Syracuse, NY
This field trip is concerned with the nature and origin of some deformation structures within lower Paleozoic cover to Precambrian basement in the vicinity of Theresa, New York (Fig. 1). Many of the structures suggest localized mobility within the basement that generated instability within the cover rocks - both during and at some time following their deposition.
All of the main stops will be within the Potsdam Sandstone (Upper Cambrian) and the Theresa Formation (lower Ordovician). A cursory examination of some of the Precambrian gneisses also will be made.
The Potsdam Sandstone in the Theresa area lies with marked angular unconformity on a Precambrian sequence of marble and quartzo-feldspathic gneisses. The sub-Potsdam surface in places is rugged with a relief in excess of 70 ft although some of this relief may be due to penecontemporaneous faulting during sedimentation (Stops 2 and 3). The relict topography in part may be due to differential erosion of alternating zones of marble and quartzo-feldspathic gneisses because in some areas the marble underlies marked topographic depressions. Where observed, the lowermost Potsdam occurs above an approximately 3-ft thick weathered zone of the basement rocks (Barber, 1977). The Potsdam Sandstone in this area typically consists of a buff to light-gray, thin-bedded to massive, silica-cemented, medium-to fine-grained orthoquartzite; minor amounts of detrital feldspar, mica, and tourmaline occur but rarely exceed 3 percent of the mode. It lacks the pink coloration of the lower parts of the formation in the north (Kirchgasser and Theokritoff, 1971; Selleck, 1978).
The irregular topography on the Precambrian profoundly influenced Potsdam sedimentation. Lowermost Potsdam rocks occur in depressions of the basement surface and these areas are characterized by syndepositional deformation structures. Rapid and large changes in thickness, breccia slides, and minor faulting suggest active faulting during deposition (Stops 2, 3 and 5). At least one of these areas is on strike with NE-trending faults within the basement to the north (R.V. Guzowski. 1977, pers. comm.; Barber, 1977; Buddington, 1934).
The overlying lower Ordovician Theresa Formation ranges in composition between dolomitic limestone to quartz sandstone, the latter being concentrated in the lower 5 to 10 ft of the formation (Stop 1). Calcite sandstones locally occur within the succession. Typically, the Theresa is thinly bedded and light gray. Convolute lamination is a locally abundant feature.
In the central part of the area (Fig. 1), Theresa limestones outcrop as outliers capping elongate low-amplitude domal folds. These are best observed within a 3-5 mi wide NNE-trending zone extending from Perch Lake in the south to Butterfield Lake in the northern part of the area. The boundaries of this zone are marked imprecisely by NNE-striking probable fault zones within the basement. The effect of these on the Potsdam-Theresa sequence is seen as instability during sedimentation in the east
(see previous discussion) and in post-depositional folding throughout the zone. The latter is particularly well developed in the central and western parts of the zone within the structurally higher Theresa Formation.
Fold-producing post-Ordovician deformation has been described from the succession to the north, in the St. Lawrence Valley (Chadwick, 1915) and post-Potsdam mineralization along veins and joints throughout the region close to the contact with the Precambrian attests to Phanerozoic thermal reactivation of parts of the basement (B.W. Selleck, 1978, pers. comm.). This may have been accompanied by major faulting that deformed the overlying cover. No faults of regional extent have been observed to cut the cover rocks in the Theresa area (Barber, 1977).

STOP 1. Junction Rt I-81 and Rt NY 411
The lowermost part of the Theresa Formation is exposed on both Sides of this road cut in the hinge zone of an elongate, NE-trending dome (Fig. 2). It is typical of many of the upright to steeply inclined gentle anticlinal folds in the region that occur as relatively high ground separated by broad synclinal or undeformed rock underlying the intervening low and usually poorly drained ground. This 'first order' topography is characteristic of the western and central parts of the area. The fold trends N33°E, and the hinge line plunges NE at approximately 12° at this locality. The interlimb angle is around 160 and no measurable layer thickness variation occurs across the fold.
To the south the hinge-zone widens and extends for at least a mile. Minor folds are present in a relatively flat-lying axial zone.
Three recognizable but dispersed joint sets traverse the fold with mean trends of N74°E, N46°E, and N50°W (Barber, 1977). Probably only the N46°E set is related directly to folding because on rotation of the beds to the horizontal their poles develop a tight zero plunge cluster whereas the remaining two sets become more dispersed. On the northwestern limb, joints of this set dip steeply to the southeast whereas on the southeastern limb, dips are steeply to the northwest; they probably are extensional 'ab' fractures developed during the folding process. The N74°E and N500W post-date folding.
Other features at this locality include: low-angle joints striking NE within the hinge zone suggesting a compressional origin for at least parts of the fold; and a calcite-pyrite mineralization in places occurring along joints of the N74°E set.
The origin of the folds of the type represented at this locality is enigmatic. They are, however, unlikely to be syndepositional and a glacial origin is not convincing because glacial striae throughout the area do not hold any systematic relationship to fold trends. The present evidence indicates a tectonic origin, either as localized deformation within the Lower Paleozoic rocks resulting from faulting within the basement or from concentration of strain at abrupt changes in relief, and therefore a probable thickness variation in the Potsdam Sandstone. Relatively high strain at the Potsdam-Theresa boundary or within the transitional zone between the two lithologically distinct formations has not been supported by the limited observations possible at this stratigraphic level. The regional shortening required for such low-amplitude folds is extremely small.
A comparison with a fold of known glacial origin (Stop 5A) will be made following Stop 5.

STOP 2. English Settlement Road
Exposures are of Potsdam Sandstone typical for this area (Fig. 3). Hematite staining has accented crossbedding, minor slump structures and small-scale lamination. In some occurrences, however, the staining is independent of any internal structure and may be described as 'liesegangbanding'.
Bedding is folded in a manner typical of the lower part of the Potsdam Formation. Hinge lines are tenuous and variable in orientation, and individual beds thicken and thin greatly through short distances. The most obvious fold at this locality is one of a series of irregular gentle undulations of bedrock, between which are small areas underlain by Grenville rocks or horizontal Potsdam strata. The hinge-line of the fold trends approximately N40°E. Other folds in the area exhibit a similar trend wherever hinge lines can be determined accurately (Fig. 3).
The railroad cut transects the southern end of the fold at an oblique angle, and expresses a hinge-zone as well as the northwestern limb. The central part of the fold is comprised of horizontally bedded Potsdam and shows no evidence of deformation. On the limb, however, are a number of features indicative of pre-induration deformation. Approximately 10 ft from the northern end of the outcrop, a massive sandstone layer abruptly deflects downwards and terminates against an adjacent underlying layer. Overlying layers exhibit annealed fractures and lumpy, contorted bedding as they form a flexure over the zone. The flexure has been propagated to the top of the exposure.
Strata to the south, for a distance of approximately 65 ft, form the fold limb, which dips between 5° and 10° toward the northwest. The sandstone is cut by fractures, some of which are differentially weathered normal faults of small displacement (usually less than 0.5 in) that dip to the northwest. Some of these are filled with granular quartz.
On the limb, beds pinch and swell and may change from massive to shaly character through distances of 10 ft or less. Most crossbedded layers are thin and crossbeds are planar.
A major slump structure occurs near the fold crest (partially obscured by a pine tree). At the lower part of the outcrop, a portion of a large slump block is exposed. Poorly layered sandstones within and adjacent to the block are separated by a narrow zone of homogeneous disturbed sandstone.
The abundance of features indicative of soft-sediment deformation suggests that these folds, which generally occur adjacent to topographic highs of the basement, formed by rapid downslope movement during and closely following sedimentation.

STOP 3. Theresa Village
This outcrop is located on the Theresa side of the Rt NY 26-411 bridge over the Indian River. At the cliff face on the south side of the road, Potsdam Sandstone overlies an exposure of weathered basement gneiss. The effects of initial dip are evident here as the Potsdam offlaps a knob of Precambrian rock. Irregular bedding, numerous minor unconformities and evidence of soft-sediment deformation characterize the outcrop. Where the Precambrian core has been eroded, ripples are exposed within the Potsdam that probably formed as a result of slow downslope movement of unconsolidated sediment.
Large slump blocks are exposed in the cliff face adjacent to the sidewalk. Each block is set in a matrix of sandstone that exhibits small-scale contorted laminae or is accented by hematite. The interface between block and matrix tends to be sharp, and suggests slumping of partially consolidated sediments in areas of steep paleoslope.

STOP 4. Ritchie's Farm
The high ground behind the farm buildings is comprised of variably bedded, buff-colored, lower Potsdam Sandstone that forms a broad structural basin toward the north. It is typical of all the outliers of Potsdam Sandstone in the region and its relationship to underlying Grenville. Whether this and other basins of similar type are primary is uncertain. Calculations of thickness variations in individual beds is not possible through lack of exposure.
The dominant joint sets in the Potsdam at this locality are nearly vertical and trend N42°W and N81°E, whereas those in underlying Grenville gneiss trend between N42°E and N66°E and dip southeast between 57° and 70°. The strike of these joints tends to be parallel to the strike of the main foliation, whereas dip of these same joints tends to be perpendicular to the foliation. The foliation in coarsely crystalline quartz-biotite-plagioclase (?oligoclase) gneisses, visible a few yards downhill from the Potsdam contact, strikes N68-84°E and dips northwest between 39° and 43°. This trend is consistent for all exposures of Precambrian rock adjacent to this and other nearby outcrops.

STOP 5. North of Redwood, Rt NY 37
A major basement fault with relative displacement down to the northwest is inferred to underlie the valley immediately west of the hill (Fig. 4). The hill is comprised of a structural basin containing Potsdam Sandstone similar to that at the previous stop. At the roadcut. Potsdam beds strike N41°E and dip gently southeast. They consist of both evenly and irregularly bedded sandstone containing "liesegang" type banding, conglomeratic zones and numerous soft sediment deformational structures. A large cone-shaped concretion of the type described by Dietrich (1953) is well exposed in the outcrop. The structure seems to consist of a cone within a cone, with the axis of the inner cone being somewhat offset from that of the larger, outer cone. The angular relations between bedding planes and sides of the outer cone, which is approximately 7-8 ft in diameter at the top of the outcrop, indicate that the cone may have been tilted concurrently with tilting of the bedding. Therefore, rotation of the Potsdam beds followed at least partial compaction and lithification. Dietrich ascribed the formation of these structures to slumping of semi-consolidated sands into solution cavities in underlying Grenville marble. Within and along the margins of the structure, the sandstone is chaotically bedded, and contains numerous healed fractures and small slump blocks. These conical or cylindrical structures occur elsewhere in the area, and although they suggest the importance of soft-sediment deformation, this is the only one that occurs in tilted strata.

A2: THE STRUCTURAL FRAMEWORK AND PETROLOGY OF THE SOUTHERN ADIRONDACKS
James McLelland
Hamilton, NY
Ennis Geraghty
97B Shafer Road, Apt. 1B
Albany, NY
with a section on Ledge Mountain by
Gary Boone
Syracuse, NY
The area referred to as the southern Adirondacks is shown in Figure 1. Within this region, the Precambrian is bounded approximately by the towns of Lowville and Little Falls on the west and Saratoga Springs and Glens Falls on the east.
Mapping in the southern Adirondacks was done first by Miller (1911, 1916, 1920, 1923), Cushing and Ruedemann (1914), Krieger (1937), and Cannon (1937); more recent investigations were undertaken by Bartholomew (1956), Thompson (1959), Nelson (1968), and Lettney (1969). At approximately the same time Walton (1961) began extensive field studies in the eastern portion of the area (Paradox Lake, etc.), de Waard (1962) began his studies in the west (Little Moose Mt. Syncline). Subsequently de Waard was joined by Romey (de Waard and Romey, 1969).
Separately and together, Walton and de Waard (1963) demonstrated that the Adirondacks are made up of polydeformational structures, the earliest of which consist of isoclinal, recumbent folds. Their elucidation of Adirondack geology set the tone for future workers in the area. In this regard one of their most important contributions to the regional picture was that the stratigraphy of the west-central Adirondacks is correlative with that of the eastern Adirondacks.
Beginning in 1967 McLelland (1969, 1972) initiated mapping in the southernmost Adirondacks just to the west of Sacandaga Reservoir. This work was extended subsequently north and east to connect with that of Walton and de Waard. Geraghty (1973) and Farrar (1976) undertook detailed mapping in the eastern half of the North Creek 15' quadrangle. This tied into investigations in the Brandt Lake region by Turner (1971). Recently, Geraghty (1978) completed a detailed study of the structure and petrology in the Blue Mt. Lake area. The foregoing investigations have increased our knowledge of the southern Adirondacks, and this field trip is designed to show as many examples of the region's structure, lithology, and petrology as time allows.

STOP 1: Large roadcut on north shore of Lake Durant.
This location is the type section of lake Durant Formation (D. de Waard, 1970, pers. comm.).
This stop has been described by de Waard (1964b) as follows: "The section of diverse, layered metamorphic rocks includes pink and greenish leucocratic gneisses with thin metabasic layers, marble, and calc-silicate rocks. The section forms part of the supracrustal sequence which overlies the leptites of the Wakely nappe exposed in the hills visible towards the south across the lake. and which underlies the Blue Mountain charnockite sequence towards the north. Lineations on foliation planes indicate a 30° NE plunging fold axis. The intrusive nature of marble into boudinaged layered gneiss is shown on the west end of the north side of the read cut."
Outcrop mapping to the east and south has revealed that the Lake Durant Formation contains large amounts of hornblende granitic gneiss and biotite-hornblende granitic gneiss both above and below the well-layered sequence exposed in the type section at Lake Durant. In addition, a distinctive rock sequence of biotite granitic gneiss (bottom), calc-silicate rock, and platy-quartz gneiss (top) makes up the basal portion of the Lake Durant Formation in areas to the south.

STOP 2.: Ledge Mt.
Hike 1 mi east through open woods, to well-exposed south-facing cliffs. This is on the southward culmination of the recumbent Ledge Mountain antiform. Quartz-sillimanite lenses increase in size and relative amount from west to east. until they assume the proportions of major layering in the gneiss. Kyanite occurs here in two feldspar-rich portions of the gneiss. We have sought more, without success. If you should discover additional kyanite, PLEASE OBSERVE PETROLOGIC ETIQUETTE OF PHASE PRESERVATION: NOTIFY TRIP LEADER, WHO WILL OFFER SUITABLE REWARD. Note different proportions of magnetite, garnet, and biotite in feldspathic portions of gneiss, as well as in pegmatite. The structural relationships of pegmatite to host gneiss also differ. Note in Figure 21A that biotite compositions within garnet porphyroblasts are Mg-richer and Al-poorer than "Free" matrix biotite. Also, of the four plagioclase-garnet equilibria shown in Figure 21B (representing five pairs), all represent 'probed rims of grain pairs each of which is in mutual contact. The highest-P boundary is that calculated for a relatively large plagioclase grain within a garnet porphyroblast; the others are of small plagioclases within garnet porphyroblasts, and of "free" plagioclases against garnet rims.
It is deduced from these relationships. and from ubiquitous but small-scale late corona structures of albite on magnetite, that the path of P-T change was prograde along a geothermal gradient which penetrated the kyanite field, followed by partial melting and decrease of lithostatic pressure into the sillimanite field and retrograde cooling within that field, with residual kyanite being trapped within feldspar-rich (solidus?) portions of the gneiss.

STOP 3: Scenic overlook on E side of Route NY 30.
Mountainous area to the southeast is part of the Thirteenth Lake complex, cored by anorthosite and charnockite. Overlying gneisses dip to the north (left) and west (towards us) off the complex. To the south metasedimentary rocks dip to the northeast off of Snowy Mountain dome (not visible), which also is cored by anorthosite and charnockite.
Walk south on highway NY 30 to roadcut on west side of road. This roadcut is composed of a distinctive "diopside-clot" gneiss and is situated close to the axial core of the Crow Hill synform. The rock is a zircon-apatite±plagioclase±calcite±garnet-sphene-scapolite-clinopyroxene-quartz-microcline granulite. It is part of the distinctive basal portion of the Lake Durant Formation.
Chemical compositions of scapolite and clinopyroxene from this unit at another location were determined by electron-probe microanalysis to be Me69, and salite, (CaO.93,NaO.06)0.99(M90.62,FeO.39,MnO.Ol,Al0.02)1.04(Si1.96 Al0.04)2O6, respectively. Plagioclase composition is oligoclase, An21, based on petrographic determinations using the zone method of Rittman.

STOP 4: Anorthosite-charnockite suite of rocks
Described by de Waard (1964) as follows: "Large road-cut on the hill 0.4 miles southwest of the intersection of highway 30 with the lake shore road through Sabael. Anorthosite at the lower end of the outcrop is overlain by metanorite (unfoliated andesine-pyroxene-hornblende gneiss) which is in turn overlain by streak andesine-pyroxene-hornblende augen gneiss. Both "Marcy-" and "Whiteface-" type anorthosites are present. The grain size of metanorites ranges from coarse to fine, and the original texture of the rock is preserved to various degrees in different parts of the exposure. Several small amphibolite (metadolerite) lenses may be observed in the streak gneiss. Foliation is nearly horizontal. Walk up the steep hillside above the road to see massive ledges of anorthosite, metanorite, and a rock which is texturally and compositionally intermediate between these two types."
The origin of, and relationships within, the anorthosite-charnockite suite of rocks has been debated for decades. Those favoring a comagmatic association have tended to postulate a dioritic parent magma which yields plagioclase (anorthositic) cumulates and charnockitic residua (de Waard and Romey, 1969). Those who do not accept a comagmatic relationship between these rocks, have generally postulated a parent of gabbroic anorthosite composition (Buddington, 1972). A variant of the gabbroic anorthosite parent is the high-alumina basalt of Morse (1975).
The snowy Mt. Dome is the type area of de Waard and Romey's (1969) comagmatic differentiation process. By detailed mapping beginning at the core of the dome, they showed that there exists an outward gradation from central anorthosite through metanorite, to noritic augen gneiss, to charnockitic gneisses (see Fig. 22). This they interpreted as reflecting a differentiation sequence and variation diagrams were constructed to portray these trends.
A critical aspect of the compositional variation within this suite is that grains (xenocrysts) of andesine occurs within the charnockitic rocks. These xenocrysts increase in abundance as the anorthositic core rocks are approached. Concomitantly the amount of K-feldspar and quartz decrease. Although these changes do result in a gradation of rock types, the transition seems to be mechanical rather than chemical. This is suggested by the constancy of xenocryst composition and the widespread presence of cross-cutting relationship between end-member rock types.
Based upon field and chemical data Buddington (1939, 1972), suggested that the charnockitic rocks are distinctly later than, and unrelated to, the anorthositic rocks. He presented variation diagrams of major oxides demonstrating that the anorthositic and charnockitic rocks follow separate differentiation trends and that discontinuities exist between their paths. Simmons (1976) and Goldberg (1977) have studied trace element and REE patterns in Adirondack anorthosite-charnockite lithologies and concur with Buddington that the two are unrelated. They also show that a gabbroic anorthosite parent is consistent with their trace-element studies. Simmons suggests that such a parent can be produced from dry melting at high load pressure of a gabbroic source rock. Figure 23 shows Emslie's (1971) results for such a system at P = 15 Kb and at 1 atm. The minimum melt generated at 45-50 km is essentially a gabbroic anorthosite. As it rises the field boundaries move so as to enlarge the domain of plagioclase crystallization. In this manner anorthosites may result from reasonable petrogenetic processes.
The origin of the charnockitic rocks in the suite remains largely unresolved. Buddington (1972) suggests that they represent an independent magma series in which contamination of granitic magma by garnetiferous amphibolite has been important. Husch, Kleinspehn, and Mclelland (1975), as well as Isachsen, McLelland, and Whitney (1975), have suggested that the charnockite-mangerite envelope results from fusion of quartzo-feldspathic country rocks of the intruding anorthositic magma (crystal mush ?). Early in the process the anorthositic rocks attain complete crystallization and are subsequently intruded by the lower melting temperature quartzo-feldspathic lithologies. Wiebe (1975) has suggested a similar mechanism for adamellites near Zoar (Nain), labrador. All fusion models of this sort depend critically on the initial temperature of the charnockitic rocks and the heat budget within the system. Although the lack of data on heat capacities, heats of fusion. etc. preclude detailed calculations, it does seem possible that at 8-10 Kb anorthositic intrusives with temperatures of 1200-1300°C can melt substantial quantities of quartzo-feldspathic gneisses initially at 800°C. Whether or not this mechanism actually operates is a question deserving of extensive research. It is certainly consistent with field evidence suggesting that stratigraphically continuous units undergo increasing anatexis as anorthositic rocks are approached. Some examples of this anatexis will be seen at Stop 7.

Charnockites of the Snowy Mt. Dome.
These type "a" quartzo-feldspathic gneisses tend to be more massive than charnockites higher in the sequence. They also contain xenocrysts of andesine. de Waard and Romey (1969) believed that these charnockites were comagmatic with the anorthosites of the Snowy Mt. Dome. Buddington (1963) has argued that they are later than the anorthosites. Isachsen, McLelland, and Whitney (1975) suggested that these, and similar, charnockites are the products of melting accompanying intrusion of the anorthosites into quartzo-feldspathic country rocks. Rb/Sr whole rock ages obtained by Hills and Isachsen (l975) yield results of ˜1.2 by and do not suggest that these charnockites are part of an "older" basement complex.

Lake Durant Fm. and the Lower Marble
The lower Lake Durant Fm. and the Lower Marble are exposed in this general vicinity.

Contact of the Lower Marble with the Lake Durant Fm.

Contact of the Lake Durant Fm. with the Upper Marble.

Passing through thick charnockite layer in the Upper Marble.

Passing through units of the Upper Marble.
Generally low dips have resulted in broad exposure of this unit. Note horizontal foliation in some roadcuts.

Cross contact with Blue Mt. Fm
Cross contact with Blue Mt. Fm. which cores a local F2 syncline.

Contact of Blue Mt. Fm. with Upper Marble.
Passing into the southern limb of the F2 syncline.

Garnetiferous amphibolite in Upper Marble
Long roadcuts of garnetiferous amphibolite in Upper Marble. Some garnets attain diameters of 5-6", A large pegmatite is also present. Note that this outcrop sits astride the hinge line of an F2 anticline.

Contact of Upper Marble amphibolites and Blue Mt. Fm.

Charnockites of Blue Mt. Fm.

Cross into Upper Marble

STOP 5. 3.3 miles east of Speculator, New York.
The Upper Marble Fm. is exposed in roadcuts on both sides of the highway. These exposures show typical examples of the extreme ductility of the carbonate-rich units. The south wall of the roadcut is particularly striking, for here relatively brittle layers of garnetiferous amphibolite have been intensely boudinaged and broken. The marbles, on the other hand, have yielded plastically and flowed with ease during the deformation. As a result the marble-amphibolite relationships are similar to those that would be expected between magma and country rock. Numerous rotated, angular blocks of amphibolite are scattered throughout the marble in the fashion of xenoliths in igneous intrusions. At the eastern end of the outcrop tight isoclinal folds of amphibolite and metapelitic gneisses have been broken apart and rotated. The isolated fold noses that remain "floating" in the marble have been aptly termed "tectonic fish." The early, isoclinal folds rotate on earlier foliation.
Features such as those seen within this roadcut have led this writer to question the appropriateness of assigning an unconformity to the base of the lower Marble Fm. Tectonic phenomena in rocks of high viscosity contrast can account for the fact that the marbles are able to come into contact with a variety of lithologies.
A variety of interesting lithologies are present in this roadcut. The marble itself contains diopside (now serpentinized), tremolite, tourmaline, graphite, sphene, phlogopite, and a variety of pyrites. Interesting reaction rims, or selvages, exist between the marbles and quartz-rich boudins. Presumably these selvages reflect the influence of compositional gradients during metamorphism. Quartz and calcite coexist in these rocks, and wollastonite is not known to occur at this location.
Most of the amphibolites in the outcrop are highly garnetiferous and some layers seem to contain 60-70 percent garnet. The garnets are almandine-rich and are similar to those at Gore Mt. However, it is not known whether these amphibolites represent metamorphosed sedimentary or igneous rocks. Note that a number of the garnets are separated from surrounding hornblende by narrow light colored rims. These consist of calcic plagioclase and orthopyroxene and represent products of the reaction:
Garnet + Hornblende = Orthopyroxene + Calcic Plagioclase + Water.
This reaction is characteristic of the granulite facies wherein the association garnet + hornblende is unstable (de Waard, 1965a, 1965b).
Also present in the outcrop are various layers rich in calc-silicates. One of these contains coarse, pale diopside crystals several inches across. Others consist almost entirely of green diopside. Tremolite also occurs in some layers. Rusty weathering, metapelitic units are rich in graphite, calc-silicates, and pyrite. Neither grossular nor scapolite seems to have developed here.
Near the west end of the outcrop a deformed layer of charnockite is well exposed. In other places the charnockite-marble inter-layering occurs on the scale of one to two inches.
Exposed at several places in the roadcut are striking, cross•cutting veins of tourmaline and quartz displaying a symplectic type of intergrowth. Other veins include hornblende and sphene-bearing pegmatites.
Usually included in the Upper Marble, but not exposed here, are quartzites, kinzigites; sillimanite-rich, garnetiferous, quartz-microcline gneisses; and fine-grained garnetiferous leucogneisses identical to those characterizing the Sacandaga Fm. These lithologies may be seen in roadcuts 0.5 mi to the south.
Almost certainly these marbles are largely of inorganic origin. No calcium carbonate secreting organisms seem to have existed during the time in which these carbonates were deposited (> 1 by ago). Presumably the graphite represents remains of stromatolite-like binding algae that operated in shallow-water, intertidal zones. If so, the other roadcut lithologies formed in this environment as well. This seems reasonable enough for the clearly metasedimentary units such as the quartzites and kinzigites. The shallow-water environment is much more interesting when applied to the charnockitic and amphibolite layers. The fine-scale layering, and ubiquitous conformity of these, strongly suggests that they do not have an intrusive origin. Perhaps they represent the metamorphosed products of volcanic material in a shelf-like environment. Such intercalation is now occurring in many island arc areas where shallow-water sediments cover, and in turn are covered by, ash and lava. Alternatively they may represent metasediments.

STOP 6: Core rocks of the Piseco Anticline.
Hinge line of Piseco Anticline near domical culmination at Piseco Lake. The rocks here are typical quartzo-feldspathic gneisses "a" such as occur in the Piseco Anticline and in other large anticlinal structures, for example Snowy Mt. Dome, Oregon Dome.
The pink "granitic" gneisses of the Piseco Anticline do not exhibit marked lithologic variation. Locally grain size is variable and in places megacrysts seem to have been largely granulated and only a few small remnants of cores are seen. The open folds at this locality are minor folds of the F2 event. Their axes trend N70W and plunge 10-15' SE parallel to the Piseco Anticline.
The most striking aspect of the gneisses in the Piseco Anticline is their well-developed lineation. This is expressed by rod, or pencil-like, structures. These may consist of alternating ribbons of quartzite, quartzo-feldspathic gneiss, and biotite-rich layers. In many instances these ribbons represent transposed layering on the highly attenuated limbs of early, isoclinal minor folds. Near the northeast end of the roadcut such minor folds are easily seen due to the presence of quartzite layers in the rock. Slabbed and polished specimens from this and similar outcrops demonstrates that these early folds are exceedingly abundant in the Piseco Anticline. Examination of these folds shows that the dominant foliation in the rock is axial planar to them. Similarly, layer transposition is related to flattening parallel to the axial planes of the early folds. The intersection of this axial plane foliation and compositional surfaces helps to define the strong lineation in the outcrop. Also present is an earlier foliation subparallel to the one associated with the visible folds. Again intersections between these foliations, compositional surfaces, etc., result in a strong intersection lineation. In addition to this a number of rod-like lineations are probably the hinge line regions of isoclinal minor folds which are difficult to recognize because of relative lithologic homogeneity. Lineation in the outcrop is intensified further by the fact the upright and relatively open F2 folds are coaxial with F1. Thus the intersection of the F2 axial planar foliation with earlier foliations results in a lineation parallel to the F2 trend. Moreover, F2 minor folds may be of the crenulation variety and their sharp hinge lines define a lineation in the earlier foliation. As described previously. a number of parallel elements combine to produce an extremely strong lineation in the Piseco Anticline. Past observers have remarked that the lineation appears to be the result of stretching parallel to the long axis of the Piseco Dome. However, the lineation is probably unrelated to "stretching" and is explained more realistically as an intersection lineation of planar fabrics. Moreover, the intensity of the lineation is more the result of the early recumbent folding and flattening than it is of the later, coaxial F2 Piseco Anticline.

Red-stained quartzo-feldspathic gneisses "a"
On both sides of Rt. NY 10 are red-stained quartzo-feldspathic gneisses "a" that have been cataclastized by a large N20E fault zone. For the next 5.5 mi we shall pass through a number of road-curves as Rt. NY 10 makes its way through the core rocks on the south limb of the Piseco Anticline.

STOP 7: Lake Durant and Sacandaga Fms.
Lake Durant and Scandaga Fms. intruded by anorthositic gabbros and gabbroic anorthosites.
These roadcuts are located on Rt. NY 10 just south of Shaker Place.
The northernmost roadcut consists of a variety of metasedimentary rocks. These lie directly above the Piseco Anticline and are believed to be stratigraphically equivalent to the Sacandaga Formation. The outcrop displays at least two phases of folding and their related fabric elements. These are believed to be F1 and F2. A pre-F1 foliation is thought to be present. Both axial plane foliations are well developed here. Several examples of folded F1 closures are present and F1 foliations (parallel to layering) can be seen being folded about upright F2 axial planes.
Farther to the south, and overlooking a bend in the west branch of the Sacandaga River, there occurs a long roadcut consisting principally of pink and light green quartzo-feldspathic gneisses belonging to the Lake Durant Fm. About half-way down this roadcut there occurs a large and impressive boudin of amphibolite and diopsidic gneiss. To the north of this boudin the quartzo-feldspathic gneisses are intruded pervasively by anorthositic gabbros, gabbroic anorthosites, and various other related igneous varieties. At the north end of the cut and prior to the meta-stratified sequences these intrusives can be seen folded by upright fold axes. They are crosscut by quartzo-feldspathic material.
Within this general region the lake Durant Fm. and other quartzo-feldspathic gneisses seem to have undergone substantial anatexis. This is indicated by the "nebular" aspect of the rocks. Good examples of this are seen in the manner in which green and pink portions of the quartzo-feldspathic gneisses mix. Note also the clearly cross-cutting relationships between quartzo-feldspathic gneiss and mafic layers at the south end of the roadcut. Here it seems that mobilized lake Durant is cross-cutting its own internal stratigraphy. Also note that the quantity of pegmatitic material is greater than usual. This increase in anatectic phenomena correlates closely with the appearance of extensive metagabbroic and metanorthositic rocks in this area. We believe that these provided a substantial portion of the heat that resulted in partial fusion of the quartzo-feldspathic country rock.

Excellent examples of anorthositic gabbros
Roadcut on west side of highway shows excellent examples of anorthositic gabbros intrusive into layered pink and light green quartzo-feldspathic gneisses. The presence of pegmatites and cross-cutting granitic veins is attributed to anatexis of the quartzo-feldspathic gneisses by the anorthositic rocks.

Fine-grained metagabbro on west side Rt. NY10.

Excellent roadcut in coarse anorthositic gabbro.
Ophitic to sub-ophitic texture well preserved. Garnets are sporadically developed and tend to be associated with coarse gabbroic pegmatites showing mineral growth perpendicular to contacts. Compositional layering may be primary.

Begin half-mile of roadcuts
Begin half-mile of roadcuts exhibiting intrusion of quartzo-feldspathic gneisses by members of the anorthositic gabbro suite, several phases of which seem to be present and in cross-cutting relationships. Source metasedimentary areas may be xenoliths. Pods of megacrystic gneiss may be anatectic in origin.

Kennels Pond - Avery's Fishing Site.

Lake Catherine to east of highway
Lake Catherine to east of highway; metasediments intruded by anorthositic gabbros in roadcut on west.

Avery's Hotel on west of highway at top of hill.

STOP 8. Kinzigites
On the west side of Rt. NY 10 is a rounded roadcut consisting of typical examples of sillimanite-garnet-biotite-quartz-oligoclase gneisses (kinzigites). These rocks are widespread south of the Piseco Anticline and are thought to represent meta-pelites associated with a locally deeper sedimentary basin in this region. Throughout the Adirondacks kinzigites are rich in white pods and lenses consisting of perthitic feldspars, garnet, and quartz. These are believed to be anatectic in origin. These anatectic areas seem to pre-date F1. In places they exhibit the pre-F1 foliation. Locally they show "fishhook-like" terminations suggesting that they have been involved with substantial transposition.
The kinzigites at this locality have been intruded by anorthositic gabbro which may be seen at the north end of the roadcut. The gabbroic rocks seem to gently transect the earliest foliation but have been involved in all other deformations.
Towards the southern end of the roadcut several generations of minor folds may be seen together with their associated foliations. The earliest recognizable folds have near-horizontal axial planes where they are located on the hinge lines of the upright set of folds that dominates the outcrop. The older set seems to fold a foliation and is assigned to the F1 generation. This requires that the dominant, upright set with its steep foliation belongs to the F2 generation of folds. If this is so we note that the F2 -related axial plane foliation can be locally intense. There seem to be two generations of garnet within most kinzigites. One may be flattened in the plane of foliation and may have formed by an amphibolite facies reaction similar to:
biotite + muscovite + quartz ----> garnet + K-feldspar + H2O
(Engel and Engel. 1962). The later generation of garnets grow across foliation planes and in several areas form coronitic rims around sillimanite. These garnets are believed to result from a reaction of the following type:
sillimanite + (Fe,Mg,Ti)Biotite + Quartz-> (Fe,Mg)Garnet + Ti-Biotite ± Ilmenite + H2O

Extremely garnetiferous kinzigites.

Crossing Swamp.

Contact between Sacandaga Fm. and Rooster Hill Fm.
Crossing swamp that marks contact between the Sacandaga Fm. and megacrystic gneisses of the Rooster Hill Fm.

Megacrystic gneisses of Rooster Hill Fm.

Type locality of Rooster Hill Fm.
North end of Stoner Lake. Type locality of Rooster Hill Fm. The Rooster Hill Formation is characteristic of a wide spread lithology throughout the Adirondacks. Its most characteristic feature is the presence of striking 1-4" megacrysts of K-feldspar, These are almost always flattened within the plane of foliation. Nonetheless, a number of these megacrysts preserve evidence of approximately euhedral crystal outline.
Compositionally the Rooster Hill megacrystic gneisses consist of orthopyroxene, garnet, hornblende, biotite, perthitic microcline, some plagioclase (oligoclase), and quartz. An igneous analogue would be quartz monzonite.
The parentage of the Rooster Hill megacrystic gneisses is obscure. It is not known whether the megacrysts are phenocrysts or porphyroblasts. The fact these lithologies are conformable with the enclosing stratigraphy over broad areas is consistent with a metastratified origin but does not rule out intrusion as sills. The lack of substantial banding across units thousands of feet thick is less consistent with a metasedimentary origin than with an igneous one. However, the problem remains unresolved and requires further research. Regardless of parentage, the Rooster Hill Fm. seems to correlate with the Blue Mt. Fm.

Contact of Rooster Hill Fm. and Peck Lake Fm.
Crossing contact of Rooster Hill Fm. and kinzigites of the Peck Lake Fm. Near the contact the Rooster Hill megacrystic gneisses become equigranular. This is probably due to cataclasis.

A3: FAUNAL ASSEMBLAGES IN THE LOWER HAMILTON GROUP IN ONONDAGA COUNTY. NEW YORK
J.C. Brower, O.B. Nye, Jr., R. Belak, E.F. Carey, H.E. Leetaru, M. MacAdam, S.A. Millendorf, A. Salisbury, J.A. Thomson, P.O. Willette, S. Yamamoto
Department of Geology, Syracuse University, Syracuse, NY
This report summarizes a quantitative study of the paleoecology of the lower Hamilton Group in Onondaga County. This paper describes the faunal elements recognized and the ecological categories into which the taxa were grouped. The study confirms and extends the important works of Cooper (1930. 1933). Information concerning the multivariate statistical techniques, sedimentological data, and detailed analysis of the environments studied will be published elsewhere.
In Onondaga County the Hamilton Group directly overlies the Seneca limestone of the Onondaga Formation. Samples were taken from the Marcellus Formation, Skaneateles Formation, and the lower portion of Ludlowville Formation (Fig. 1). Although Rickard (1975, p. 6) notes that the Cherry Valley merges with the Seneca Member of the Onondaga limestone in the western part of the State, we have followed the traditional course in treating the Cherry Valley with the Hamilton Group.

STOP 1: Top of the Onondaga Limestone
Top of the Onondaga Limestone and basal Union Springs Shale displaced by a small thrust fault.
The upper 8 ft of the Onondaga Limestone and about 10 ft of the Union Springs Shale are exposed on the side of the deep drainage ditch on the east side of the road. Exposures of the top contact of the Onondaga such as this are rare.
The Union Springs is the basal member of the Marcellus Formation. The three pelagic assemblages characterized by Styliolina fissurella, Pterochaenia fragilis, and Leiorhyncus limitare occur in the Union Springs.
At the south end of the drainage ditch a thrust fault with a throw of about 5 ft cuts the top of the Onondaga but is absorbed in the Union Springs Shale above by complex crumpling and jointing.

STOP 2. Chittenango and Cardiff shales.
The Chittenango and Cardiff Members of the Marcellus Formation are exposed at this stop. Both are sparsely fossiliferous, but representatives of the wood assemblage and the Leiorhynchus assemblage as well as scattered fish scales and pyritized cephalopod shells occur.
This shale is quarried by the Alpha Portland Cement Company for use in cement manufacture at its Jamesville plant. Although these shales are similar in appearance, they can be distinguished easily by their streaks. The Chittenango Shale, because of its relatively high content of carbonaceous matter, streaks brown when scraped by a hard object such as a geologic hammer, whereas the Cardiff streaks light gray. Examination of drill core from several test holes has shown that the change in color of the streak takes place within a vertical interval of 3 ft. The contact is placed where, in going downward, the streak becomes distinctly brown. Located in this manner, the contact is near the top of the lower face, 5 to 6 ft above the upper layer of large septarian concretions. Many of the septarian concretions in the upper part of the Chittenango are several ft across. The Cardiff shale on the other hand has only a few concretions and these are seldom more than 6 inches in diameter. The cracks within the septarian concretions commonly contain calcite, ferroan dolomite, and white, platy barite. Small crystals of barite with some pyrite also coat joint surfaces in the shale in places.

View of Allied Chemical Corp., Solvay Process Division Quarry on left.

STOP 3: Monocline in the Onondaga
Monocline in the Onondaga Limestone and exposures of the Union Springs Shale, Cherry Valley Limestone, and Chittenango Shale Members of the Marcellus Formation.
Walk south up the stream for about 500 ft to where the top beds of the Onondaga Limestone exposed in the stream bed dip northward due to the presence of a monocline that strikes about N70°W. This monocline probably grades into a thrust fault in the Solvay Process Division's quarry. Solution-widened tension joints are well-developed in the limestone on the monocline.
Continue up the stream to where it forks. About 15 ft of Union Springs Shale and about 3 ft of Cherry Valley Limestone are exposed at a small waterfall on the left branch not far from the fork. The Union Springs consists of black shale with numerous thin beds of black limestone. Styliolina fissurella, a small mollusk, shaped similar to a pencil point, is abundant in the shale of the upper part of the member. The Cherry Valley limestone forms the lip of the falls. It is characterized by a mixed pelagic and bottom dwelling fauna which includes cephalopods, the coral, Aulopora, brachiopods, trilobites, and crinoids. The basal few feet of Chittenango Shale, exposed in the stream bank above the falls, contains one or more thin beds of black limestone. Numerous Styliolina fissurella can be seen on the bedding surfaces of some of the shale.

STOP 4: Pompey Quarry
About 15 ft of the Pompey Member (Skaneateles Formation) is exposed here. The Pompey is a rather clean, coarse siltstone to fine sandstone which is crossbedded and may display current ripples. The Actinopteria and the Zaphrentid coral assemblage can be examined here. Each is concentrated usually along single bedding planes. Although the Zaphrentids usually are lying on their sides, they may be in growth positions.

STOP 5: Skaneateles Formation
Road cut in the Pompey, Delphi Station, and Mottville Members of the Skaneateles Formation. This cut exposes about 115 ft of the Pompey, Delphi Station, and Mottville Members. The 8 ft of siltstone at the top of the cut is Cooper's Eunella-Nyassa zone that marks the top of the Pompey, the same unit that forms the lip of Pratts Falls. The siltstone grades downward into gray shale.
The contact between the Delphi Station and the Pompey Members is not located easily and is one of the problems to be considered at this stop.
The Mottville is a fine-grained silty, somewhat calcareous, gray shale. Only the uppermost few feet can be seen here. The Tropidoleptus carinatus assemblage has been collected at this locality.
The overlying Delphi Station is a dark-gray, fine-grained shale with smaller amounts of calcium carbonate but more organic matter than the underlying Mottville. The relatively diverse Nuculoidea-Bembexia assemblage occurs here.
In the top-most Pompey Member, the muds of the Delphi-Station are replaced by current-rippled crossbedded siltstones. The Nuculoidea-Bembexia assemblage occurs in the lower portion to be replaced by the Actinopteria assemblage in the upper portion.

STOP 6: Delphi Station and Pompey Members
Delphi Station and Pompey Members of the Skaneateles Formation.
Observe the upper beds of the Pompey Member exposed near the top of the falls. Walk right on path along the edge of the gorge to where the falls can be observed.
The top 60ft of the falls is Cooper's (1930, Am. Jour. Sci. v. 19) type section of the Pompey member. The resistant siltstone beds that form the lip of the falls are his Eunella-Nyassa zone that marks the top of the Pompey, distinguished by the presence of Eunella lincklaeni, Athyris cora, and Nyassa arguta. The lower part of the falls exposes the upper part of the Delphi Station Member. The Mottville Member which underlies the Delphi Station is exposed a moderate distance downstream from the falls.

STOP 7: Small shale quarry
Small shale quarry in the Butternut Member of the Skaneateles Formation.
The Butternut is a bioturbated silty shale which contains the Leiorhynchus laura assemblage. This assemblage also occurs in the thin-bedded siltstones and silty shales of the Mottville and Delphi Station.

STOP 8: Otisco Member of the Ludlowville Formation.
Stop opposite the yellow brick house. Walk about 100 ft up the hillside on the west side of the road to exposures of siltstone strata that form a bench on the hillside. This is the siltstone platform on which the Staghorn Point coral biostrome was formed. It is about 50 ft above the base of the Otisco Member of the Ludlowville Formation and is an important horizon marker in the Syracuse area.
In the upper siltstone beds are numerous molds of corals representative of the Otisco coral assemblage.
In the lower siltstone platform, are several think discontinuous fossil-rich layer which contain members of the Mucrospirifer mucronatus assemblage.

STOP 9: Road cut in the Centerfield Member
Road cut in the Centerfield Member of the Ludlowville Formation. About 6 ft of the relatively clean, crossbedded fine sandstones of the Centerfield are exposed. Both the Mucrospirifer mucronatus assemblage which occurs concentrated along bedding planes and small patches of the Zaphrentid coral assemblage can be examined here. Glacial striae can be seen at the top of the outcrop.

A4: GEOMORPHOLOGY OF THE SOUTHEASTERN TUG HILL PLATEAU
Ernest H. Muller
Syracuse. NY
Few areas of comparable size in New York State are less accessible or less well known than the heart of the Tug Hill Plateau. The heaviest snowfalls in the eastern states make for brief growing seasons. Extensive tracts cleared and farmed in the past century have returned to second growth. The road net involves only jeep trails between a few broadly spaced transverse highways.
Although isolated by peripheral lowlands --the Black River Lowlands on the north and east, the Ontario lowlands on the west and the Oneida-Mohawk lowlands on the south --the Tug Hill is a crudely triangular outlier of the Southern New York Section of the Appalachian Plateaus Province. Rough accordance of summit elevations (e.g. 1960 ft at Gomer Hill. 1920 ft at Mohawk Hill) led Newell (1940) to relate physiographic history of the Tug Hill to that of the adjacent Appalachian Plateaus to the south, ascribing a major role to Tertiary peneplanation. Regional dip southwesterly away from the Adirondack Massif led Hanefeld (1960) to stress the cuestaform nature of the Tug Hill. The scarped east-facing border of the plateau contrasts with the gradual southerly and westerly dip slopes. Indeed both peneplanation and cuestaform development convey true, but incomplete impressions of the regional character of the Tug Hill subprovince. Each is incomplete in failing to emphasize the role of prolonged and repeated Pleistocene glaciation in isolating the plateau, in reducing summits and in shaping present topography. Perhaps because of the erodibility of underlying rocks, these effects are maximized in the southeastern portion of the plateau.
Rocks of Ordovician and Silurian age underlie the Tug Hill Plateau. At the base of the sedimentary section are carbonate rocks of the Trenton and Black River Groups which lie unconformably upon Precambrian metasediments of the Adirondack terrane. From Forestville north to Carthage, the contact between sedimentary and metamorphic rocks lies roughly along the course of the Black River and presumably exerted structural control upon development of the Black River Lowlands. Trenton, Utica, and Frankfort Formations of Ordovician age comprise the stepped and cuestaform eastern margin of the plateau. They also underlie the narrow, southeastern extension of the subprovince where regional dip approximates regional slope from the Black River to the Oneida-Mohawk Lowlands. As a result, Utica Shale underlies both northern and southern margins of this southeastern portion of the subprovince. The youngest Paleozoic strata of the plateau are the red and green sandstones and shales of the Medina Group which lie unconformably upon Queenston, Oswego and Lorraine rocks in the southwestern portion of the Tug Hill.
Knowledge of the geology of the Tug Hill has long been based chiefly on inference from studies in the peripheral lowlands. Surficial geology, for instance, was inferred from studies such as those of Taylor (1924), Stewart (1958) and MacClintock and Stewart (1963) in the St. Lawrence Lowlands; of Miller (1909a , 1909b), Fairchild (1912), Buddington (1934), Tyler (1938) and Force, Lipin, and Smith (1975) in the Black River Lowlands. Kaiser (1962) showed the responsiveness of glacial drift to immediate bedrock provenance and inferred prevailingly southeasterly glacial flow across the Tug Hill. Street (1966) on lithologic criteria delineated the interlobate area of rapid transition from characteristic eastern (Black River lobe) to western (Ontario Lobe) till in the area west of Ava. Jordan (1977, 1978) studied glacial deposits in the heart of the Tug Hill with a view to distinguishing relationships of wetland types to glacial geology. More specifically, published geologic information relating to the southeastern portion of the Tug Hill subprovince involves geologic mapping of the Remsen (Miller, 1909a), Oriskany (Dale, 1953) and Utica (Kay, 1953) quadrangles, surficial mapping by Wright (1972) and regional correlation by Fullerton (1971, in press).

Route follows the lowest of the Syracuse Channels
This route follows the lowest of the Syracuse Channels by which proglacial meltwater drained from Onondaga Trough east toward the Mohawk Valley. Exposures of Syracuse Formation in its type area are visible south of Erie Boulevard on right.

Floor of proglacial Lake Iroquois
Travel east across plainlands, the floor of proglacial Lake Iroquois. This area underlain by nonresistant Vernon Shale accounting for basin. Bedrock topography with local relief of 150 ft in next few miles is concealed by postglacial lake sediments.

Sandy, stone-free soil in fields on left.
Ephemeral strand line of low lake phase that succeeded Lake Iroquois in the Canastota mucklands is in trees at left. Dune modification of the back-shore sands is visible briefly and better developed along Chestnut Ridge Road which parallels the Thruway to the north.

Vernon Shale
Vernon Shale exposed in low roadside cut on right (south) side of eastbound lane, opposite Chittenango Service Area. For next several miles the strand of Lake Iroquois trends parallel to Thruway on the South.

Wampsville
One mile south of the Thruway, not readily visible is Wampsville, site of Madison County Courthouse. A well on the property of Hubbard Industries located near a Lake Iroquois spit, taps an artesian system at 90 ft and flows a reported 700 gallons per minute. Gravel pits south of Route NY 5 in Wampsville expose two impermeable lodgment tills with intervening permeable cobble gravel.

Iroquois barrier bar on right
Iroquois barrier bar on right about 0.2 m; before railroad underpass. Leave bed of Lake Iroquois.

Herkimer Sandstone of uppermost Clinton Group
Herkimer Sandstone of uppermost Clinton Group exposed south of eastbound lane discontinuously for 0.25 mi.

Descend and cross Oriskany Creek.
Roadcuts expose stratified drift indurated at base, overlying firm, dark-gray, silty clay till.

Whitestown Esker
Small gravel pit beneath power line was opened in the Whitestown Esker which parallels route on the right.

STOP 1. Stream cut bluff of Oriskany Creek
Stream cut bluff of Oriskany Creek, exposing intercalated lodgment tills and deformed lake sediments overlain by firmly cemented fluvioglacial gravel. The section records multiple oscillations of the Late Wisconsinan ice margin into pro-glacially impounded waters.

Stratified drift
A few exposures of stratified drift across Oriskany Creek on the right. Out of sight to the south, the Whitestown Esker leads to the kame moraine south of Oriskany which fronts on the Oriskany-Whitestown Sand Plain at approximately 550 ft above sea level. Numerous exposures in bluffs facing the Mohawk River show the Sand Plain to be underlain by 80+ ft of horizontally bedded sand and gravel, capped by 10 to 20 ft of coarse cobble gravel, in part firmly cemented with calcium carbonate.

Shale exposed in roadside ditches and gully at right.

Rise onto pitted outwash plain.
Irregular closed depressions due to melting of buried stagnant ice masses on both sides of road. Surface of undissected plain is about 525 ft above sea level, graded below the Oriskany-Whitestown Sand Plain. This surface is a sandur built where meltwater streams flowing along the margin of a progressively receding ice front spread onto the open valley floor.

Cobble gravel in a few low knolls
The extensive sand mantle gives way to cobble gravel in a few low knolls. East of the road, weak channel development trends ESE.

Marginal meltwater channel
A well-developed, flat-floored marginal meltwater channel 250-300 ft wide, and cut into Utica Shale opens onto the sandur west of Floyd. North of Floyd, rise on drift mantled slope which in places shows low constructional topography.

STOP 2. Gifford Hill Roadcuts
Exposure of multiple tills, intercalated with partially indurated intraglacial stratified drift units.

Eastward dipping foreset
Note indurated, eastward dipping foreset cobble to boulder gravel in roadcut on right.

Narrow, steep-walled defile
Eastward from Frenchville, Route NY 274 occupies the floor of a narrow, steep-walled defile incised by Wells Creek. Cut 200-ft deep in postglacial time, the gorge owes its character to rapid incision and the erosivity and vertical jointing of the Utica Shale. The gorge is incised into a fluvioglacial terrace at 800 ft above sea level built eastward into the Steuben Basin.

Outflow used to be to the east
Prior to incision of the Wells Creek Gorge, this part of the basin of Big Brook was impounded. As long as the ice margin blocked westward drainage, outflow was east past Merrick Corners and down Steuben Creek. Freeing of the Mohawk Valley north of Rome initiated westward drainage, leading to incision of the gorge.

Climbing from flood plain to proglacial lake
climbing from flood plain of Big Brook to floor of proglacial Steuben Lake. Nearshore sands exposed in borrow pit on right. Just beyond borrow area, roadside ditch exposes oxidized calcareous lodgment till with silt-loam matrix.

OPTIONAL STOP
Gully at right exposes black Utica Shale over Trenton Limestone. Roadside exposures contain dark gray till glutted with Utica Shale material near base, but with bright clast lithologies dominated by blue-gray carbonates with subordinate red sandstone and metamorphic rock types.

Vista southeast over Steuben Valley.
Note increasing abundance of metamorphic boulders beyond this point.

LUNCH STOP. Baron Steuben State Memorial Park.

Pass Capel Ucha, Cemetery
Pass Capel Ucha, Cemetery on site of old Welsh Church established 1804.

Cross meltwater channel

STOP 3. Barneveld Kame Complex
Extensive gravel and sand pits expose coarse cobble gravel overlying thick stratified coarse sand section.

"Drumlin lodge" on right; not a drumlin sensu stricto.

Minor moraine ridge cuts across road
Minor moraine ridge cuts across road, then seen on left, south side of road.

Kettles in stagnant ice zone

Course of proglacial meltwaters
Turn left, north, on Route NY12, roughly parallel to Cincinnati Creek and the course of proglacial meltwaters which drained from proglacial Lake Forestport in the south end of the Black River Valley. This region is broadly underlain by Trenton Limestone.

Floor of Lake Forestport
Swampy lowlands now drained by Cincinnati Creek comprised part of the floor of Lake Forestport.

End moraine remnants
End moraine remnants looping across valley presumed to mark minor still-stand of Black River glacial lobe.

Alder Creek Moraine
At Alder Creek, cross dissected Alder Creek Moraine built while the Black River glacial lobe impounded the southward-draining proglacial Lake Forestport in area of present Kayuta Reservoir. Westward, Alder Creek moraine includes extensive stagnant ice deposits and the Echo Lake Esker.

Dissected remnants of kame moraine
Park Hill and Sperry Hill to right (east) of Route NY 12 in southern outskirts of Boonville are massive sand and gravel mounds, interpreted as dissected remnants of kame moraine.

STOP 4. Allied Chemical Company, Boonville Limestone Quarry.
Formerly Delia's Quarry, as access to Sugar River. We do not have permission to examine the quarry as such. Warning: beware of mosquitoes, algal slime on rocks in stream bed, poison ivy, and cow patties! Objective is to examine classic solution pits in limestone and subterranean piracy in progress.

Locks of the old Black River Canal
Note masonry of several locks of the old Black River Canal in roadside exposures. first on the left (east), then on the right (west) side of the road. Built in 1855 to link navigable reaches of the Black River north of Lyons Falls with the Erie Canal at Rome, the Black River Canal was only briefly economical. With a total of 109 locks in 35 mi. the canal crossed a divide 700 ft above the Erie Canal.

Morainal topography
Morainal topography on right (west). Large sand and gravel knoll on left (east). Similar to Sperry and Park Hills. Descend 30 ft to valley floor.

Channel across Trenton Limestone ledge rock
Crossing the broad, flat-bottomed rock-floored channel across Trenton Limestone ledge rock at the head of Boonville Gorge. This ledge controlled outflow from proglacial Port Leyden Lake. Cross feeder canal for Black River Canal. Continue south parallel to an incised and constricted channel-way, thence crossing diagonally back to west side of valley to parallel the old Black River Canal.

Shale bluff in roadcut on right
Shale bluff in roadcut on right indicates erosivity of rock into which the Boonville Gorge is cut. To this point the valley has become progressively narrower. The distance that minor ridges of the Alder Creek Moraine project southward down Boonville Gorge indicates prior meltwater drainage toward Rome.
At left, across Boonville Gorge, lansing Kill enters from the east side of the valley. Originating as a meltwater stream marginal to the Alder Creek Moraine on the flank of Potato Hill. Lansing Kill has, from this point down valley inherited the valley of a short-lived but powerful stream, the outlet of proglacial Port Leyden Lake. Postglacial incision by Lansing Kill accounts for abrupt deepening of the narrow inner gorge at this point. Its proglacial predecessor deepened the valley some 175 ft.

OPTIONAL STOP: Pixley Falls, Boonville Gorge State Park

"Five Combines"
"Five Combines" - a Flight of 5 adjacent locks where the old Black River Canal crosses a limestone ledge on the side of Boonville Gorge.

Mohawk River enters Boonville Gorge from west
Mohawk River enters Boonville Gorge from west with multiple terraces now incised by both Lansing Kill and Mohawk. The highest terrace, above 1000 ft is an ice marginal delta plain. Lower terraces have correlatable equivalent remnants on the east wall, indicating they were fluvial and graded to lowering base level controls in the Mohawk Valley to the south.

Grave of William Floyd
Grave of William Floyd, signatory of Declaration of Independence is on right. Floyd Homestead was on left.

Vista across Delta Reservoir
Vista across Delta Reservoir, artificially impounded in the basin created by deposition associated with Stanwix glaciation across the mouth of Boonville Gorge. In postglacial erosion the Mohawk River failed completely to recover the bedrock valley. At the site of the Delta Reservoir Dam, it incised a steep-walled, 80-ft deep defile into Utica Shale.

The route now crosses a gravel plain (sandur)
The route now crosses a gravel plain (sandur) similar in origin to the plain of Nine-mile Creek crossed this morning. Marginal meltwater channels pinned against the plateau margin to the north here spread onto the basin floor.

Former Village of Delta
Half a mile west of this point was the Village of Delta. Inundated by construction of the dam in 1911, it survives only in the name of the reservoir that supplanted it.

Traveling over Rome Sand Plains

Continue southwest across Rome Sand Plains.
Following demise of Lake Iroquois the sandy sediments delivered by Fish Creek and other streams draining the Tug Hill were vulnerable to wind erosion as indicated by low dune and blowout topography.

Abandoned Erie Canal
Route NY46 follows the abandoned Erie Canal which has been restored as parkway, canoe, and bicycle path.

A5: BENTHIC COMMUNITIES OF THE LUDLOWVILLE AND MOSCOW FORMATIONS IN THE TULLY VALLEY, ONONDAGA COUNTY
Prof. Geoscience Dept.
Rochester, New York 14623
The Devonian System in New York State varies from carbonates below (Ulsterian and lowest Erian Series) to coarse continental clastics at the top (Chautauquan Series), and represents a westward migrating deltaic complex built during Middle and Late Devonian time.
This deltaic complex, the Catskill Delta, is today represented by a wedge of sedimentary rock that thickens and coarsens eastward. The clastic wedge is pierced at several horizons by relatively thin, but geographically widespread, lithologically distinct units that do not change facies as rapidly as the rocks above or below. Serving as time planes, these key beds subdivide the clastic wedge into a number of major time-stratigraphic units. Three carbonate keybeds in the lower portion of the wedge serve to subdivide the lowest time stratigraphic unit, the Hamilton Group (Middle Devonian), into four formations, which are from oldest to youngest: the Marcellus, Skaneateles, Ludlowville and Moscow Formations.
The Middle Devonian Hamilton Group of New York State is structurally simple and highly fossiliferous, thereby lending itself to detailed stratigraphic, paleontologic, and paleoecologic studies. In Central New York it consists of approximately 1,000 feet of shales, silty shales and siltstones lying above the Onondaga Limestone and below the Tully Limestone. The stratigraphic relations of the Hamilton Group of New York as now understood were first clarified by Cooper's classic papers (1930, 1933).
The Hamilton rocks in the Tully Valley dip to the south 25° west at approximately 48 feet per mile, based upon the Centerfield Member as a datum (Grasso. 1966). The value obtained for the dip agrees with Cooper's (1930) estimate of 45 to 50 feet per mile to the southwest.
Superimposed on the regional dip are local low anticlines and faults. A thrust fault with associated folding occurs just south of Marcellus along NY Route 173 (Smith, 1935). Oliver (1951) shows conclusively that several normal faults, downthrown to the north, occur on the southwest side of the Tully Valley near Lords Hill. A thrust fault in the Onondaga Limestone and overlying Union Springs Member can be seen 1 mile south of Nedrow (Prucha, 1964, p. 49).
HAMILTON SECTION IN THE TULLY VALLEY
In the Tully Valley, the Hamilton is composed mainly of two facies that transgress time westward. The lower is a fissile black and dark shale facies of the anaerobic distal basin containing a low diversity primarily pelagic fauna. Lying above this facies in the Tully Valley, but partly contemporaneous with it farther to the east, is one representing a subtidal shelf-delta platform environment of silty shales and siltstones carrying a high diversity benthic fauna. The Ludlowville and Moscow Formation typify this facies in the Tully Valley.

STOP 1. Joshua Sub-member (15')
STOP 1. Base of tower on Miller Hill, Joshua Sub-member (15')

STOP 2. Roadcut on west side of LaFayette Rd.
About 30' of the Upper Otisco Member and the Mucrospirifer-Spinocyrtia-Megastrophia Community is exposed here.

US 20 built on surface of large hanging delta

STOP 3. Roadcut on NY 80
Joshua Sub-member (Elev. top 1280')

STOP 4. Roadcut on NY 80
Owasco (2') Portland Point (10') Members (Elev. 1380')

STOP 5. Peppermill Gulf
Peppermill Gulf just east and parallel to Hogsback Rd. Centerfield Member (20-30')

Descend Eastside Tyler Hollow
Descend Eastside Tyler Hollow Nine Mile Creek (Otisco Lake outlet)

Old Borodino Quarry
Bioherm in Tully Ls. on left and roadcut on NY 41

STOP 6. Staghorn Point.
This is the type section of the Staghorn Point Sub-member (4'). The siltstone platform and overlying Otisco shales are well exposed here.

Bucktail Falls Ravine
Bucktail Falls Ravine on right exposing the entire Upper Hamilton Group from the Centerfield Member to the Tully Ls.

STOP 7. Fellows Falls Ravine
Fellows Falls Ravine down from Woodmancy Rd. A complete section in the Ludlowville Form. is exposed at this locality as follows:
Owasco | 2' | Elev. 1120' Falls at top of ravine
Spafford | 25'
Ivy Point | 40'
Otisco | 165' | Staghorn Point 7'
Centerfield | 20' | Elev. 880'

NY 80 follows Moraine crest of Tully

Descend north side of Tully Moraine

STOP 8. Unnamed ravine on east side of Tully Valley
Unnamed ravine on east side of Tully Valley up from NY 11A. The section exposed here is similar to Fellows Falls Ravine (STOP 7) with the exception of the lower Otisco covered from the Upper Centerfield to the Staghorn Point siltstone platform. The Owasco is also not exposed here. (NOTE : This stop may be omitted depending on time schedule).

STOP 9. Tinkers Falls Ravine
Tinkers Falls Ravine up from east side of NY 91. About 80' of Windom is exposed here with the Tully ls. forming the cap rock of Tinkers Falls (Elev. 1380' )". The
Mucrospirifer-Chonetes Community is well exposed in the first exposure upstream at base of

STOP 10. Roadcut on east side of US 11.
About 30' of Windom is exposed here carrying the Mucrospirifer-Chonetes Community.

A6: PALEOENVIRONMENTS OF THE POTSDAM SANDSTONE AND THERESA FORMATION OF THE SOUTHWESTERN ST. LAWRENCE LOWLANDS
Bruce W. Selleck
Colgate University, Hamilton, New York
In northwestern New York State the Upper Cambrian-Lower Ordovician Potsdam Sandstone and Theresa Formation exhibit a variety of primary structures and compositional and textural variations indicative of deposition in nearshore, usually tide-dominated, settings. The purpose of this paper is to provide a descriptive overview of these units, plus an interpretation of the depositional environments of the various lithofacies.
In the study area) the Potsdam and Theresa are best exposed in the Frontenac Axis region. In this area the Paleozoic rocks lie in profound unconformity upon a paleoerosional surface underlain by metamorphic rocks of Proterozoic age.

STOP 1. Outcrop on both sides of road.
This outcrop displays the angular unconformity between the Potsdam Sandstone and Proterozoic rocks metamorphosed during the Grenville Orogeny (approximately 1.1 billion years ago). As the Potsdam here is approximately 500 million years old, the unconformity represents some 600 million years of missing geologic history. The Potsdam here is typical Potsdam I lithofacies. Note the general absence of trace fossils in the Potsdam, the scarcity of metamorphic clasts in the basal Potsdam and the weathering and loading deformation of the Proterozoic rock along the unconformity.

Excellent exposures of Potsdam I on right.

STOP 2. Outcrop on both sides of road.
This outcrop again exposes the angular unconformity between the Potsdam Sandstone and Proteroizoic metamorphic rocks. Of major interest at this stop are the striking color patterns in the Potsdam. Glacial polish on the top of the outcrop reveals numerous generations of color streaks. The coloring agent of the sandstone is mainly Fe2O3 (hematite) but titanium oxides and other trace minerals are locally important. The coloring oxides occupy a variety of petrographic positions in thin section, occurring as grain coatings, oxidation "halos" around detrital opaque minerals and as disseminated blebs and flecks in secondary silica cement.

Excellent exposures of Proterozoic metamorphic rocks.
Beginning of excellent exposures of Proterozoic metamorphic rocks. These continue for 1.5 miles.

STOP 3. Outcrop of right side (SW) of road.
The contact between Potsdam I and Potsdam II lithofacies is exposed at this stop. The lower portion of the outcrop is typical Potsdam 1. The upper, massive portion is Potsdam II and is obviously riddled with trails and burrows. One burrow of interest is Diplocraterion Yoyo (see text). Odd funnel-shaped structures ("sand volcanoes"?) and glacial straiae may be observed on the top surface of the outcrop. Brecciated lenses and pods occur in Potsdam I at this stop (lower portion of outcrop on NW side of road). These breccias are interpreted to be the result of the cementation and subsequent breakup of soil-like silcrete crusts formed during periods of subaerial exposure.

STOP 4. Outcrop on both sides of road.
The contact between the Potsdam Sandstone (Potsdam II lithofacies) and the Theresa Formation (Theresa I lithofacies) is displayed prominently at this stop. The contact is marked by a color change (Potsdam -gray-white-yellow; Theresa gray-brown), a greater carbonate content in the Theresa and differences in bedding style and texture. Features to observe here include body fossils (a few discoidal gastropods and fragments of Lingulepis accuminata, an inarticulate brachiopod, trace fossils (especially diplocraterion yoyo in the upper portion of Potsdam II and a variety of primary structures (ripple marks, low angle crossbeds). Bimodal laminae in some of the low-angle planar crossbeds in Potsdam II at this stop suggest a nearshore (possibly beach) depositional environment. Note also the outcrop of Proterozoic gneiss 0.25 miles SW on Rt. 12 illustrating the probable irregularity of the pre-Potsdam erosional surface in this region.

STOP 5. Outcrop on right (SE) side of road.
The Potsdam II - Theresa I contact again is exposed at this stop. Rather.good specimens of the inarticulate brachiopod Lingulepis be obtained from the thickly bedded portions of the uppermost Potsdam near the contact. As we walk to the NE end of the outcrop, note the loss of the thin-bedded nature of Theresa I and the increase in bioturbation. This signals the base of Theresa II (Theresa IIB) lithofacies. Numerous quartzite cobbles may be seen in the otherwise fine sand of Theresa I at this stop. Mechanisms for the transport of such large particles remain open to conjecture.

The rhythmic interbedding here is typical of Theresa II lithofacies in the region. In the light-colored quartz sandstone strata (Theresa IIA) a variety of crossbed styles may be observed. Note the occasional occurrence of herringbone crossbeds. The darker (Theresa IIB) calcitic and dolomitic sandstones are intensely bioturbated resulting in the loss of all primary current-formed structures. The folding here is typical of parts of the region, and is presently under study (see article by Bursnall and Barber, this volume). A small fault also is present in this exposure.

STOP 7. The uppermost lithofacies of the Theresa
The uppermost lithofacies of the Theresa Formation, Theresa III, is exposed here. All four lithologies described in the article are observable at this stop. Numerous features indicative of subaerial exposure, including mudcracks and interclast breccias, are well exposed.

A7: BENTHIC MARINE COMMUNITIES IN THE UPPER ORDOVICIAN CLASTICS OF THE TUG HILL REGION, NEW YORK
Peter Bretsky
SUNY, Stony Brook
David Thomas
SUNY College at Oswego
The fossiliferous shales, siltstones and sandstones of the Upper Ordovician Lorraine Group are an excellent example of well-defined offshore-to-onshore benthic marine communities. Three communities have been recognized and described by Bretsky (1970), based upon the consistent and recurrent associations of the abundant invertebrate species. They are;
(1) Onniella-Sowerbyella Community: widespread; lived on muddy silts of the outer infralittoral zone; abundant brachiopods (dalmanellids, strophomenoids, atrypids), crinoids, bryozoans (trepostomes) and trilobites with gastropods (pfeurotomariids) abundant locally.
(2) Nuculites-Colpomya Community: wide spread; lived on or buried in silts and fine sands of the outer and inner infralittoral zone protected environments; abundant bivalves (nuculoids, modiomorphids, actinodonts), crinoids, and brachiopods (orthids).
(3) Ambonychia-Modiolopsis Community: patchy distribution; lived on or partially buried in medium to coarse sands in the shallow infra littoral and exposed intertidal environments; abundant bivalves (ambonychiids, modiomorphids, cyrtodonts), monoplacophorans with locally abundant gastropods (pleurotomariids, bellerophontids), crinoids, bryozoans (trepostomes) and cephalopods (orthocones).
The pattern of brachiopod-dominated offshore communities to mollusc dominated nearshore communities seen in the peri-Tug Hill region is characteristic of many Late Ordovician deposits (see Bretsky, 1969).
SUMMARY
The exposures in the Tug Hill area give a picture of the dynamics of organic change in an offshore-to-onshore depositional regime. Into this general sedimentological framework, three benthic marine communities are placed. They occupied a gently westward sloping shelf that was receiving sediment from the east and that, through time, was experiencing a long, gradual regression. What happened to the faunas in this regression? To explain the exact nature of the faunal transitions in a temporal sense, a detailed bed-by-bed analysis is necessary. For example, the Lorraine Gulf section treated in this manner provides the opportunity to analyze species over a temporal gradient. In these long ranging faunas, species replacements, species additions , species losses and mixing phenomena can be examined throughly. Set in this environmental complex, are the Changes in these populations gradual? The exposures in this area are "untapped" with respect to these questions.

STOP 1. Salmon River, stream cut exposures
Salmon River, stream cut exposures near railroad trestle. The organisms here are large, suspension feeding mollusks in the coquinite beds. Note the lack of abrasion and sorting of the shells. The deposition was in the low energy mode on a shallow, gently sloping shelf. Depositional events were episodic but not violent. The mud fauna is made up of infaunal suspension and detritus feeders. Sedimentary structures to be observed here include large dune sets. several sets of ripples and desiccation (?) features. "Turkey tracks" and "U"-shaped tubes should also be noted. This outcrop illustrates a proximal facies.

STOP 2. Salmon River Falls.
CAUTION !!! This stop involves considerable climbing; footing is poor; do not go near the brink of the falls. This outcrop exhibits the transitional nature of the Oswego-Pulaski boundary. It is the most proximal facies and here we see the last of Upper Ordovician marine sediments. Compare the features of a higher energy regime with those features of STOP 1. Inspect the nature of the fossils and biogenic structures in the Pulaski with the unfossiliferous Oswego Sandstone.

STOP 3. Lorraine Gulf.
Exposures are 0.3 miles north of intersection. Bus will not be able to travel this road. Participants will walk to exposures from here and return to bus at this point. At this outcrop a more distal facies is exhibited. The sediments were deposited early in the regressive phase. Note the taxonomic and preservational changes exhibited here. What is the same when compared to the previous outcrops?

STOP 4. Washington Park. Stream cut exposures.
This the most distal sedimentary facies. Stratigraphically, the exposures are lowermost Pulaski, just above the shales of the Whetstone Gulf Formation. Notice the fairly unfossiliferous nature of these beds (what fossils are found?) and the predominance of the shales to siltstones (compare with earlier outcrops).

A8: PUNCTUATED AGGRADATIONAL CYCLES (PACS) IN MIDDLE ORDOVICIAN AND LOWER DEVONIAN SEQUENCES
E.J. Anderson and Peter W. GoodWin
Temple University
Barry Cameron
Boston University
Hypothesis
Observations of numerous clastic and carbonate sequences as well as recent papers on asymmetric cycles (Ryer, 1977; Beukes, 1977; Talbot, 1974) have led us to the hypothesis that all geosynclinal and cratonic sedimentation occurs as upward-shallowing (aggradational) cycles following rapid non-depositional transgressions (Fig.1). The general hypothesis can be viewed as a series of increasingly interpretive statements:
1) Sedimentary sequences consist of upward-shallowing packages separated by sharply defined surfaces (punctuated aggradational cycles).
2) These sharp surfaces represent intervals of rapid transgression during which no net deposition occurs. All deposition is aggradational during relatively long stable periods following transgressive events.
3) Therefore large-scale transgression is not a continuous process but rather an episodic one. Large-scale transgressive sequences consist of numerous punctuated aggradational cycles (Fig.1): basin-wide transgression is accomplished through a series of deepenings and shoalings, not by a continual deepening.
4) Rapid transgressive episodes are caused by basin subsidence.
5) Rapid basin subsidence occurs in response to abrupt movements of the elastic lithosphere.
The primary purpose of these two field trips is to demonstrate that two chronologically distinct sedimentary sequences, representing a broad range of environments, consist entirely of punctuated aggradational cycles (PACS). These two generally transgressive carbonate sequences (Black River and Helderberg), traditionally described as successions of numerous formations and members, can be viewed in a more genetic and integrative sense as sequences of a single depositional motif: punctuated aggradational cycles. The spectrum of environments is sufficiently broad to suggest that this motif is pervasive and applicable to all paleoenvironmental situations.
A second purpose of the trips is to introduce some of the stratigraphic implications of the PAC Hypothesis. Application of the PAC idea raises questions such as:
1) What is the relationship between aggradational cycles and traditional stratigraphic units (formations and members)?
2) What are the paleogeographic implications of episodic transgression? Was paleogeography modified with each transgression? Is it still valid to view large-scale transgression as a gradual shoreward migration of a relatively fixed geographic pattern. i.e. does Walther's Law apply?
3) Can cycles and transgressive surfaces be traced throughout the basin? Are subsidence events basin-wide and essentially synchronous? If so, are transgressive surfaces the ultimate means of intrabasinal correlations?

STOP 1: Northwest Newport Quarry (locality NPQ)
Walk about 300-400 feet along the gravel road and then descend carefully the southeast section of the quarry where the lower and middle Lowville Limestone is well-exposed. Then walk west around the treed promontory to the southwestern part of the quarry where the middle upper Lowville can be examined along with fallen blocks of the Watertown Limestone. Stay away from the southern wall which is about to collapse! Ascend the grassy slope here or walk back around to the center of the treed promontory and walk up the overgrown old "roadway" to examine the Watertown Limestone at the top of the quarry. The contact with the overlying lower Trenton Kings Falls Limestone is exposed in a quarry southwest of Newport (Kay, 1953), but not here.
Three formations are exposed in the large northwest Newport Quarry: the Late Cambrian Little Falls Dolostone and the Medial Ordovician (Black River Group) Lowville and Watertown Limestones (Cameron & Kamal, 1977). The top of the sandy upper Little Falls presumably forms the quarry floor. The Lowville can be divided into a lower sandy dolomitic member (13.5') and an upper purer limestone member (21.5'). A metabentonite and a 2-foot thick argillaceous marker horizon, both useful for local correlation (Cameron & Kamal, 1977), are at about 9 and 30 feet, respectively. The Watertown Limestone at the top of the quarry is massively bedded, burrow-reworked, black chert-bearing and fossiliferous calcisiltite and calcarenite. The fauna is more diverse and fossils are more common than in the Lowville below, but they are hard to collect. Large tabulate corals, brachiopods, mollusks, and bryozoa are evident.
Ten cycles that average 4 feet in thickness have been identified: three in the lower Lowville Limestone (Cycles 1-3), six in the upper Lowville (Cycles 4-9), and at least one in the Watertown (Cycle 10). Another cycle in the Watertown is postulated by correlation with nearby exposures. The three lower dolomite Lowville cycles are interpreted as representing restricted tidal conditions. At their bases they are argillaceous and contain horizontal burrows. Horizontal algal stromatolitic laminations, fenestral fabrics, and vertical burrows occur mostly in the middle. The quartzose tops of cycles 2 and 3 may be lag deposits from tidal channels. They both contain quartz arenites at the base of the sandy beds and the upper one is quite fossiliferous. The upper Lowville contains six less restricted tidal cycles. Their bases are typically abrupt, burrow-reworked, and fossiliferous. The lower and middle parts are typically argillaceous. Towards their tops they become more micritic. Vertical burrows, intraclasts, fenestral fabrics, and stromatolitic laminations are common.
The Watertown Limestone is subtidal, possibly shallow shelf or lagoonal in nature, and less restricted than the Lowville, as evidenced by the thorough burrow-reworking and by the diverse invertebrate and calcareous algal fossil assemblages here and elsewhere. Most of the shelly fossils are concentrated at the bases of small subcycles 6 to 12 inches thick that mimic larger cycles.

Lowville Limestone
After coming down hill, continue straight onto dead end dirt road. Poor exposures of lower Trenton Group (Napanee Limestone) on left. (Do not turn right onto the large bridge over East Canada Creek. However, if the power company (Niagara-Mohawk) does not permit your trespassing, park and walk across the large bridge. Descend the left (upstream) side to the large limestone exposures at the inside of the meander to see all but the base and top of the Lowville Limestone. The 4 foot thick, Watertown-like, burrow-reworked, massively bedded subtidal facies caps the exposure).

STOP 2. Inghams Mills
Walk to right, through the grass, and proceed to the right of the wire fence, walking beneath the power lines.
At the stone wall along the edge of the field, bear left and walk along the wire fence. CAUTION: Poison ivy often grows in abundance along this path.
Opposite the brick building, turn right and proceed very carefully over to the boulders and across the creek toward the base of the outcrop. The boulders you will have to walk over to get to this exposure are sometimes unstable and tend to move when stepped or climbed upon. Be careful! Traverse at your own risk.
Three limestone formations of Medial Ordovician age are excellently exposed along with the top of the Late Cambrian Little Falls Dolostone below the dam on East Canada Creek. The Lowville here comprises the whole of the Black River Group although a Watertown-like 4-foot thick horizon occurs near the top. The Trenton Group above is represented by an unusual facies of the Napanee Limestone and the Kings Falls Limestone, including what was once attributed to the Sugar River Limestone (Kay, 1968; Cameron, 1969). At this well-exposed outcrop, the field trip participants will be encouraged to use the many paleoenvironmental criteria observable here in an attempt to recognize the punctuated aggradational cycles themselves. After an outcrop discussion, we will leave to look at Devonian cycles.
Little Falls Dolostone. Two feet of the Late Cambrian Little Falls Dolostone are exposed at this locality. The top of this unit has two feet of relief and is relatively thick-bedded, light to medium brown weathering, quartz arenitic, pyrite-bearing dolostone with thin inter-bedded shale layers.
Lowville Limestone. Approximately 30 feet of Lowville are exposed, beginning with several feet of fossiliferous gray shaly limestone at the base. Middle Lowville contains horizontally laminated (algal?) calcilutites with abundant vertical burrows, a few ostracodes, and mudcracks confirming an intertidal origin. Tide channels (Cameron, 1969; Cameron and Kamal, 1977) are well-exposed on the southern and western sides of the lower outcrop. The upper half of the formation contains subtidal fossiliferous burrow-reworked calcisiltites overlain by intertidal vertically-burrowed lithologies. The subtidal lithologies resemble the Watertown Limestone to the Northwest.
"Napanee Limestone". -The lowest 13 feet of Trenton(?) limestone consists of a lower 7.5 foot unit of chocolate brown argillaceous calcisiltites and calcareous shales overlain by a 5.5 foot unit of gray less argillaceous calcisiltites interbedded with thinner shales.
Kings Falls Limestone. Twenty-three feet of brachiopod-rich shelly, lower Kings Falls Limestone overlies the "Napanee". The upper Kings Falls (14 feet) consists of encrinitic bryozoan-rich calcarenites.
Using these general lithologies and thicknesses for stratigraphic location, field trip participants will attempt to recognize punctuated aggradational cycles from criteria demonstrated at Newport Quarry. A blank columnar section (Fig.6) is provided for recording PACS with lithologic documentation. Formational boundaries are indicated along with vertical measurements for purposes of location. After outcrop analysis by small groups of participants there will be a full-group discussion of the outcrop.

STOP 3. Jordanville Quarry
Eight cycles are exposed in the quarry, two in the upper Dayville and Elmwood, four in the Jamesville and two in the Deansboro (Fig.B). The Clark Reservation is probably not present (it appears to terminate further west). The two lower cycles (I and II) are thick and grade from coarse more argillaceous and fossiliferous beds up into fine very well sorted dune cross-stratified calcarenite. Note that these beds, which include the Elmwood Member of the Manlius, are not dolomitic algal laminites as they are further west at Munnsville and Perryville. The next three cycles in the Jamesville (III to V) are stromatoporoid-algal laminite cycles; laminites are well-developed only in Cycle III. These laminites, which are well developed in Cycle III in the north wall of the quarry, are not present less than a quarter of a mile away in the south wall. Cycle VI (Fig.B), a three foot cross-stratified calcarenite, has erosional upper and lower surfaces. This can be interpreted as a barrier island deposit bounded on the bottom by a migrating tidal inlet erosion surface and on the top by a ravinement. Cycles VII and VIII (the Deansboro) are shallow open shelf cycles consisting of bioturbated crinoid-brachiopod calcarenite which grades upward into current stratified deposits.

A9: EURYPTERID HORIZONS AND STRATIGRAPHY OF THE UPPER SILURIAN AND LOWER DEVONIAN ROCKS OF CENTRAL-EASTERN NEW YORK
Samuel J. Ciurca, Jr.
There are a number of famous faunas known from classic localities in North America. These include the "Mazon Creek" Fauna (Pennsylvanian) of Illinois, the Kokomo Eurypterid Fauna of Indiana, the Green River Fish Fauna (Eocene) of Wyoming, and the Burgess Shale Fauna (Cambrian) of western Canada. Each is characterized by an unusual abundance and variety of species.
In New York the so-called "Bertie" eurypterids are representative of one such fauna (Fig. 1). Although only one or two species of eurypterids dominate the fauna, a large number of species has been described through the years. Unfortunately, detailed stratigraphic studies of the eurypterid-bearing beds have been noticeably lacking. Until recently, the "Bertie" faunas, one from the Buffalo area (so-called "Buffalo Pool"), and the other from eastern New York (so-called "Herkimer Pool "), were thought to be contemporaneous deposits rather than distinct stratigraphic horizons.
The purpose of this paper and the associated field trip is to relate these and other eurypterid horizons to the stratigraphy of the areas. Several formations are discussed but special emphasis is given to the Chrysler Formation because it is the least known and only recently was well exposed for study.
2014: No road log, and locations are not given with sufficient information to locate them reliably. Hence, no stops or views.

A10: AN EXAMINATION OF BOTTOM SEDIMENTS IN SENECA LAKE
Donald L. Woodrow
Professor of Geology
Hobart and William Smith Colleges
Geneva, New York 14456
The purpose of this field trip is to examine data bearing on the origin of the sediments found in the northern part of Seneca Lake. These sediments are apparently typical of those found in the other Finger Lakes of New York so that learning about the processes which formed them gives insight into the general problem of the origin of sediments in these lakes and similar lakes elsewhere.
The valley in which the lake is situated has been cut into the South-dipping Devonian shales and sandstones of the Appalachian Plateau (Figure 1). Apparently, a north-flowing stream occupied the valley during the late Tertiary and then during the Pleistocene glaciers eroded and otherwise sculpted the Tertiary landscape mantling the resulting surface with a wide variety of ice-laid and water-laid sediments. Glacial processes and their effects on local geography have attracted the attention of workers since early in the nineteenth century. A current summary of investigations is given by Muller (1965).
Deglaciation took place locally between 14,000 and 12,500 years BP. During ice retreat several Moraines were draped across the land surface as well as across the floor the lakes which preceded Seneca (Figure 1). Many of the moraines formed at the northern boundary of a pro-glacial lake either as shoreline features or at the ice edge beneath a lake surface. Those moraines emplaced on the floor of what was later to be Seneca Lake were subsequently buried by lake sediments.
On this trip we will examine directly and by subbottom profile the sediment on the lake floor as well as those in the immediate subbottom available to a light dredge or piston corer.
Seneca Lake's drainage basin boundary, the lake's major tributaries. the local bedrock geology and the location of moraines are given in Figure 1.
THE TRIP
Our route carries us from the dock at the northeast corner of the lake south to the various sampling locations and back again, a total of about 10 km. (See Figure 2). While underway, we will examine the sub-bottom where possible. At the various locations we will look at bottom sediments collected by Ponar dredge and at the last stop we will examine a sediment core. Since shoreline sediments form such a small fraction of the sediments in the lake basin we will not be concerned with them on this trip.
2014: Trip is by boat, no road log, hence, no stops or views.

A11: ENGINEERING GEOLOGY AT NINE MILE POINT, NEW YORK
Joseph A. Fischer and H. Scott Laird
Dames & Moore, 6 Commerce Drive, Cranford, New Jersey
The south shore of Lake Ontario for some time has been considered well suited for many industries, among them nuclear power plants. Several plants are currently in operation along the lake shore, and plans for others are being seriously pursued.
As a result of the critical nature of the engineering structures which comprise a nuclear power plant, details of the geology, seismicity. and geohydrology of the plant site are defined to an extent generally not achieved in most geotechnical investigations. In addition, there is a lengthy and intensive peer review involved in the licensing process. This review focuses attention upon site details that might be classified ordinarily as unimportant, covered in recommendations as "our experience" or "our judgement", or in some instances, perhaps forgotten. Although we may not be pleased to "overexplain" many details of our analyses, it is difficult to agree that the discipline is not good for the soul and, in addition, that information ordinarily not available to the geotechnical profession is documented for futUre use.
The information presented in this report is an attempt to present the consultant's understanding, although somewhat broadly and generally, of the engineering geology at the Nine Mile Point site, developed through approximately 15 years of study. It is emphasized that much of the detailed and fundamental analyses that are performed ultimately in the process of providing design parameters for the facilities are based upon the parameters presented herein. Obviously, however, the details of all the design analyses are beyond the scope of this discussion. Instead, it is important to emphasize that no matter how sophisticated the analyses, ultimately they are dependent upon precise and detailed geologic data concerning the stratigraphy, structural geology, geohydrology, seismicity, and rock stresses. This presentation focuses upon the importance and relationship of the bedrock stratigraphy to the engineering decisions involved in the design and construction of the nuclear facilities at Nine Mile Point, New York.
2014: No road log, hence, no stops or views.

A12: THE TULLY LIMESTONE OF CENTRAL NEW YORK -STRATIGRAPHY AND FACIES VARIATION
John M. Cubitt
Syracuse, NY
Philip H. Heckel
University of Iowa
Iowa City, IA
Alan G. DelSignore and Michael Wooldridge
The Tully Limestone of central New York is an anomalous sequence of carbonate rocks lying within thick coarse clastic rocks of Devonian age constituting the Appalachian Basin. The thin carbonates are sandwiched between terrigenous detrital rocks thickening westwards from the Catskill Delta and represent a significant change of depositional environments through the Devonian epicontinental seas. The events leading to the development of the Tully Limestone have been described in detail by Heckel (1973) and this field trip is designed to provide a description of the Tully Limestone field relationships studied at Syracuse University within the framework of Heckel's study.

View down the Onondaga trough
On the R (SSW) observe the view down the Onondaga trough. This is one of a number of u-shaped glacial valleys characteristic of the area south of Syracuse. As glaciers receded a network of troughs and cross channels were established during the Pleistocene Epoch.

Limestone strata of the Onondaga Fm
On the L in this roadcut observe the gently folded, well-fractured limestone strata of the Onondaga Formation. Stratigraphically this formation lies conformably below the Hamilton Formation upon which the Tully Formation disconformably rests.

Differentially weathered chert layer
Through this roadcut observe the protruding, differentially weathered chert layer in the upper portion of the exposure of this Middle Devonian outcrop.

Lafayette Exit.
The shale outcrop in view is
of the Hamilton Formation.

Tully moraine terminating this trough
On the R observe the etched Tully moraine terminating this trough. It is part of the Valley Heads moraine system and is associated with kame and kettle topography representing a period of stagnation during the retreat of the glaciers in the Wisconsin Glacial Stage of the Pleistocene Epoch. Southward the moraine grades into a pitted outwash plain.

Hamilton shale and siltstones along the northbound lane.

Tree lined kettle
Off to the R (S) observe the tree lined kettle. Along the rest of the route note the gently to steeply rolling terrain and N-S trending glacially deepened valleys.

Lower and Upper Tully Fm on R, location 3c
De Ruyter Reservoir on L, lower and upper Tully Formation outcrop on R (location 3c,

STOP 1. Abandoned Quarry, location 3ab
Turn R onto Coon Rd. on shoulder and park (W. Lake Rd. has become Highbridge Rd.). The abandoned quarry is located in the postglacial stream valley upstream from Highbridge Rd. (location 3ab Heckel, 1973).

Stop 2. Tinker's Falls, location 2ac
Pull off onto shoulder or carefully cross the oncoming lane and park in widened
shoulder area. Tinker's Falls lies upstream from the road; the stream bed is just N of the
parking area across Rt. NY91. (Location 2ac, Heckel,1973)

Lower and upper Tully members, location 1h
The lower and upper Tully members are exposed along the banks of the ravine above the falls seen dead ahead from Sawmill Rd. (Bucktail Falls, location 1h Heckel, 1973).

Recut delta deposits
Viewing the NE shore of Otisco Lake observe the recut delta deposits where post-glacial streams debouche into the lake.

Stop 3. Borodino Mound Complex, location Qys
Borodino Mound Complex. (location Qys, Middle Quarry, Heckel, 1973)

Stop 4. Location 6s
Intersection with Bacon Rd., park on roadside. This last outcrop is approximately 0.7 miles along Bacon Rd. in the 3rd ravine that is crossed. (location 6s Heckel, 1973)

B2: SYRACUSE MELTWATER CHANNELS
B.M. Hand
The channels carved by Pleistocene meltwater through the Syracuse area tell an interesting and complicated story. Their discharge, which rivaled Niagara's, spilled over waterfalls having the plan dimensions of Horseshoe Falls.
Examined in detail, the channels are determined to be products of multiple episodes of cutting, infilling, and re-excavation that collectively span several glacial epochs. The most recent history is complex, because the simple south-to-north activation sequence that has been preferred in the past, turns out to have been impossible. In its place is emerging a new sequence that involves piecemeal flushing of our most spectacular channel, multiple occupation of another, a minor ice readvance in late Pleistocene time, and catastrophic release of water from a large proglacial lake when a lOO-ft drift dam failed.
The purpose of this trip will be to view the topographic features which document an ample flow of quantities of meltwater through the Syracuse area in late glacial time. It will focus, however, on the evidence for reinterpretations of the type previously mentioned. Observation will blend into inference, and inference into speculation. However, sufficient opportunities will be available for challenging the more outrageous claims that your leader, in the end, should not get away with too much sleight-of-Hand.

T-intersection with Brighton Ave
At T-intersection with Brighton Ave., view ahead (west) looks across northern end of Onondaga Trough. Downtown Syracuse is two miles to the right, at the north end of Onondaga Trough.

West end of Rock Cut cross channel.
Intersection is at west end of Rock Cut cross channel. Elevation of channel floor (road level) is 550 ft. Floor of Onondaga Trough is at about 400 ft, so depth of Onondaga Trough Lake was 150 ft when this threshold controlled. Approach to Meadowbrook Channel also was through this area. Highway excavations on left briefly exposed the following sequence:
till
flowtill
varved lake clays (about 100 yrs; upper part contorted by ice thrusting)
bedrock (Bertie Formation)
Interpretation: Bedrock was cleared of drift by drainage from Onondaga Trough Lake when Meadowbrook Channel was active. (Western end of Rock Cut was still drift-filled.) Readvance of ice blocked Meadowbrook outlet, raising level of Onondaga Trough Lake from 550 ft to 700 ft, reactivating Nottingham Channel. Lake clays were deposited in this interval. Upward increase in dropstones indicates approach of ice front. Ice over-ride then contorted upper part of clay and deposited flowtill and till. This minor re-advance is thought to have been limited to tongues of ice extending southward into "through" valleys.

Spectacular view of Onondaga Trough.
We are approximately on the shoreline for the lake as it would have been during the Smoky Hollow Stage. The lake was 2 mi wide, 350 ft deep, and extended to the Tully Loop of the Valley Heads Moraine, 13 mi south.

Cut-off meander loop of Smoky Hollow Channel
Cut-off meander loop of Smoky Hollow Channel is on right. Loop surrounds an umlaufberg, 3 mi to the east can be seen the east side of Jamesville Trough, and beyond it (about 8 mi away) the far (east) wall of Fayetteville-Manlius Trough.

Begin descent into Smoky Hollow.

This road follows the main Smoky Hollow Channel.

Loop channel on right.

Umlaufberg on right.

Loop channel returns from right.

Jamesville Reservoir (artificial lake) on left.

View (southward) of Jamesville Trough.

Excellent view of Jamesville Trough.

Crossing southernmost scour-way of Moorehouse Flats.

Moorehouse Flats for next 0.4 mi.
Discharge from Jamesville Trough Lake swept eastward (to right) across this threshold on Onondaga Limestone during the Smoky Hollow Stage.

Jamesville quarry of Allied Chemical Corp
Artificial barrier on left partially hides Jamesville quarry of Allied Chemical Corp, which extends for 1.5 miles along the route. Quarry is in Onondaga and Manlius Formations.

High Bridge Channel / Fayetteville-Manlius Trough
Crossing axis of High Bridge Channel (left) where it enters Fayetteville-Manlius Trough (right).

STOP 1. High Bridge Delta
High Bridge Delta, an expansion bar built where White Lake Channel entered Fayetteville-Manlius Lake. At least the final shaping is attributed to catastrophic discharge which occurred when a 100 ft drift dam failed in Rock Cut Channel. Observe large-scale cross-stratification, clast size (mostly sand and pebble gravel, with larger clasts to 6 ft or more), and clast lithology (dominantly carbonate, but some exotics). Till occurs immediately below a cemented gravel zone in the deeper parts of the quarry.

Climb delta face. Main channel on left.

Road is on top of High Bridge delta (expansion bar)
Road is on top of High Bridge delta (expansion bar), elevation 600 ft. Floor of channel (on left, not clearly visible) is at 530 ft. If the topography here is essentially primary, as it appears, flow in the main channel was 60-70 ft deep during delta construction (Rock Cut flood).

Descend into scour channel
Descend into scour channel maintained by vortex in lee of Rock Cut Delta. The near (northeast) wall of this scour channel is bedrock while the southwest side is the depositional front of Rock Cut Delta.

Bedrock exposures on left.

Bedrock behind houses on right
Bedrock behind houses on right was swept bare by vortex scour.

Dead ahead is slip face of Rock Cut Delta.
Delta forests here consist of pebble gravel, with basal layer of boulders thought to have been emplaced by rolling down the delta face. Some of these boulders are used as yard ornaments.

Cross scour channel and climb delta front.

Boulders 4 to 6 ft long
Here on top of Rock Cut Delta the favored lawn ornaments are boulders 4 to 6 ft long. Most are of local bedrock types, but some are exotics. These boulders occur at an elevation of 600 ft, about 50 ft above the floor of Rock Cut Channel, along which they were transported.

Note the broad, channel-like depression to the left
Note the broad, channel-like depression to the left on the grounds of the Dewitt Fish and Game Club. This scour-way is 700 to 1000 ft wide; its axis lies about 35 ft below the adjacent delta surface and slopes gently westward. i.e., up-current. It is interpreted as having developed during catastrophic discharge from Rock Cut Channel, when water level stood near 500 ft elevation. Presumably, most, if not all, of the delta surface was under water at one time, but scour-ways such as this accommodated a disproportionate part of the flow.

Fluvial boulder gravels in road cut on left.
The valley into which we are now descending was cut subsequent to formation of Rock Cut Delta and so transects the delta, isolating the remnant we have just crossed from other remnants on the west side of Jamesville Trough.

Till in roadcut on left
Till in roadcut on left shows that the flow which sectioned Rock Cut Delta (Rams Gulch phase) cut completely through the delta gravels and into glacial deposits underneath.

STOP 2. Turn left into abandoned gravel pit.
Large boulders near entrance are common constituents of this segment of the Rock Cut Delta. Whether this pit can be examined in detail depends on interstate highway construction and other factors. However, under favorable conditions one can see imbricate boulder gravels and crossbedding that document radial flow from the mouth of Rock Cut. The till surface on which the delta was built forms the floor of the quarry over large areas. The edge of this delta spills northwestward into the mouth of Nottingham Channel, clearly indicating that the flood gravels (which initiated State II of Rock Cut drainage and built most of this delta) are younger than the most recent flow through Nottingham.

Gravels beyond houses on left
Gravels beyond houses on left are part of the delta built by discharge from Smoky Hollow spilling into Jamesville Trough Lake.

STOP 3 and LUNCH. (Parking lot, Clark Reservation.)
From main overlook, observe the steep-walled plunge basin at the west end of Clark Reservation Channel. This dry waterfall, 120 ft high, has plan dimensions nearly identical with those of Horseshoe Falls, which today carries 90 percent of Niagara's discharge. Presumably, the normal flow through Clark Reservation in late Pleistocene time was comparable to that of the present Niagara River. Green Lake, which now occupies the plunge basin, is about 55 ft deep. A second, smaller plunge basin (Dry Lake) is located immediately upstream from the lip of the main falls. Its height was only about 50 ft.

Trailer Park Plunge Basin
Hike from the parking lot north, then west, following park boundary service roads and foot trail to the south rim of Rock Cut Channel. From the overlook one can see the trailer park plunge basin 170 ft below. This was the earlier of two south-wall plunge basins to be active during Phase I of Rock Cut drainage. By this time, drift had been flushed from the east end of Rock Cut, at least to the 600 ft level. The proposed Rock Cut drift barrier was located immediately west of here. The boulder spit partially barring the plunge basin was constructed by catastrophic discharge when the dam failed.

Dramatic view of Rock Cut, looking upstream (west).

Trailer Park plunge basin on left.

Circle park on perimeter road.
Turn right and circle park on perimeter road. (This is private property, so permission should be requested.)
Immediately after turn, note artificially truncated spit on right. Boulder layers dip southward at angle of repose, indicating accretion into plunge basin accompanied lengthwise growth. Original basin form has been modified through removal of talus and addition of about 30 ft of fill.
Boulders have been known to tumble to the base of the talus or slightly beyond, and have caused some concern.

Second (western) plunge basin
On left was location of the second (western) plunge basin which was operative immediately prior to diversion of the flow to Nottingham Channel. The basin has been enlarged by quarrying operations, and effectively destroyed. The ridge immediately south of the road is what is left of the boulder spit, which once completely barred this plunge basin. Its top stands more than 80 ft above the floor of Rock Cut. Some individual boulders exposed during excavation were 8 ft long.

Location of drift barrier
Location of drift barrier which diverted flow to south wall plunge basins, later to Nottingham Channel, and finally failed, releasing the Rock Cut flood.

View into Rock Cut, looking downstream.

STOP 4. Approach to Nottingham Channel
You are parked in the approach to Nottingham Channel. Incision is not obvious because the flow was spread wide. However. much of the bedrock has been scoured free of till, and there remain patches of gravel that were deposited by the meltwater.
Walk NE into the wooded area, to view the plunge basin at the upstream end of Nottingham Channel.

B3: LATE PLEISTOCENE HISTORY OF SOUTH-CENTRAL ONONDAGA COUNTY
David E. Andrews and Richard Jordan
Central New York State offers much for the glacial geomorphologist including examples of both erosional and depositional features associated with the continental ice sheet. Within south-central Onondaga County many of these morphological as well as associated stratigraphic units can be seen. Some pose intriguing problems relating to the chronology of events leading to their birth and subsequent survival. The scope of previous work ranges from broad regional approaches to localized detailed analyses and has been reported in numerous publications and theses (e.g., Blagbrough, 1961; Brainerd, 1922; Durham, 1958; Fairchild, 1899a, l899b, 1905, 1907, 1909, 1932; Grasso, 1970; Kirkland, 1970; Krall, 1966; Muller, 1964; von Engeln, 1921, 1961). The purpose of this report is to furnish the reader with a short and generalized account of late Pleistocene history of southern Onondaga County. This is supplemented with Figure 1, which depicts approximate terminal zones associated with post-Olean glacial advances.

Rock Cut channel
Look southeast and observe a steep walled, flat bottomed channel. This is Rock Cut, one of several major meltwater channels which controlled the eastward escape of impounded glacial waters.

Rock Cut channel and Onondaga Trough
To the left (E) is the channel - elev. 550 ft. To the right (W) is Onondaga Trough, elev. of valley floor is approximately 415 ft.

Outcropping of Elmwood Formation
Outcropping of Elmwood Formation; a portion of the scarp developed on Manlius Group.

Drumlinoid of bedrock with veneer of lodgment till.
On right (W) SUNY - College of Environmental Science & Forestry - Experimental Station. On left (E) LaFayette Golf Course located at base of drumlinoid composed of bedrock with thin veneer of lodgment till. This is typical of upland streamlined features of this region.

STOP 1. Entrance - Smoky Hollow Meltwater Channel
Discussion of character of channel and relationship to Onondaga Trough History, including preview of broad deltas visible in valley to southwest.

Cross ancillary channel
Cross ancillary channel developed during initial stages of Smokey Hollow. Elevation of bedrock at junction of this channel and Smokey Hollow is approximately 780 (a depth of 50 ft)

Borings found sand and gravel over till
Borings at this intersection encountered 24 ft of sand and gravel overlying 17 ft of till. No bedrock was encountered.

Water tanks on subdued kamic topography
Note the water tanks positioned on subdued kamic topography; adjacent uplands to south are bedrock controlled.

Note coarseness of till
Cross under Route 181; note coarseness of till. Road on right leads to LaFayette Landfill approximately 1/2 mi to north. It is located in deltaic sediments deposited in a lowering proglacial lake (elevation 1040±)

STOP 2. Stream Cut - Kennedy Creek
On right (W), across stream is bouldery till overlying light brown sands. Beneath this is a red-gray silty clay.

Close-up of bouldery till in roadcut.

Enter small meltwater channel.

Reenter meltwater channel.

STOP 3. Overview Of Tully Moraine
Discussion of its development as well as other prominent glacial features.

Note cemetery on right (w) and gravel pit on left (E).
These are located on a zone of drift tentatively correlated to the Port Huron advance.

STOP 4. Overview Of Rattlesnake Gulf
Discussion of its development and its relationship to the deglaciation of Tully Valley.

Start of Valley Heads Moraine
Start of constructional topography of Valley Heads Moraine (proximal end)

Leave morainal topography
Leave morainal topography and reenter streamline topography.

Outwash plain formed by Valley Heads Ice.
This gradually sloping surface to the south is the outwash plain formed by Valley Heads Ice.

The rolling hills on left (E) are lateral moraines
The rolling hills on left (E) are lateral moraines associated with the "advanced" Valley Heads Ice. The tree line emphasizes the break between the moraine and the bedrock escarpment.

Gradual change into a zone of pitted outwash.

STOP 5. Gravel Pit South Of Green Lake
Examination of features and materials of pitted outwash plain.

Outwash to pitted outwash to kame and kettle
Note the procession from outwash to pitted outwash to kame and kettle topography as the "moraine" is approached.

STOP 6. Allied Chemical Corporation Gravel Pits
Discussion as to mode of origin of the "moraine".

Bedrock crops out on right, valley fill on left

On left (E) kame field grades into kame terrace.
This is believed to reflect one of the positions for the "advanced" Valley Heads Ice.

On right (W), small remnants of lateral moraine.

Lateral moraine on right and continues down valley.
A portion of it has been cut for a parking lot for Song Mountain Ski Resort. Farther south the moraine becomes partially buried by colluvium.

Last vestige of lateral moraine
Last vestige of lateral moraine as it dips under road and into outwash.

Note that slope changes from dipping south to north.
This represents the distal edge of a fan built from Otisco Valley and lies above the Tully Valley outwash.

Classic example of a truncated spur.
On left is von Engeln's (1961) classic example of a truncated spur.

Descent from the terrace cut into outwash gravels.
These were deposited by meltwaters from Valley Heads Ice in Otisco Valley.

Outflow channel and borrow pits
Scarp of outflow channel on right (E); on left (W) two borrow pits which are remnants of the dissected plain. Above these are vestiges of a lateral moraine deposited during "advanced" stage.

To south is a partial ridge across the valley.
It merges with the "advanced" stage lateral moraine on east wall and can be traced northward past Gulf Rd.

On right is a second "advanced" lateral moraine.

The proximal edge of the Valley Heads "moraine".
On the west wall, remnants of a nearly horizontal lateral moraine can be seen. The valley drops over 500 ft to Otisco Lake. Strong Rd. follows the moraine onto the uplands.

Cross high-level meltwater channel
Cross high-level meltwater channel which carried water into Otisco Valley.

STOP 7. Amber Delta
Discussion of its character and mode of origin.

Kames, delta and eroded lake clays
The hummocky terrain is a result of a complex relationship between kames, delta and eroded lake clays. Borings taken at the dam suggest a terminal ice position. This is correlated tentatively with the Port Huron advance.

Red clays exposed in the slump
The red clays exposed in the slump occur throughout this portion of the valley and create many slope stability problems.
Continue along road and observe clay mounds and "moraine" to north.

Kamic topography and morainal features
Observe the kamic topography and morainal features on left (N).

STOP 8. Sand Pit - Masters Rd.
Consideration of the nature and history of the deposit.

STOP 9. Guppy Gulf And Bishop Hill Delta
Further discussion of deglaciation history of the area.

Road cuts through moraine and delta
The road cuts through the moraine near the base of the hill and then transects a delta built into the preglacial lake impounded south of the moraine.

Three minor meltwater channels
Proceeding north, three well-developed minor meltwater channels are traversed. Water flowed from east to west and deposited the above mentioned deltaic sediments.

Till over sand and gravel
Borings and wells in this upland region generally encountered over 50 ft of till overlying a thick layer of sand and gravel.

Note kamic topography on side hill to southeast.
This is associated with small morainal belt which is believed related to a post-Port Huron readvance. The valley in the foreground is the northern extension of the Navarino Meltwater channel which supplied sediments to Amber Delta.

Navarino Channel.

Morainal belt with small meltwater channel
On left (N) is portion of morainal belt mentioned above with small meltwater channel formed between drift and uplands.

STOP 10. Overview Of Cedarvale Deltas
Discussion of large-scale morphological features and generalized history of deglaciation.

Cobble-boulder delta remnant
On left is cobble-boulder delta remnant at elevation 640 ft

Scarp to the right
The scarp to the right is a result of erosion through the deltaic deposits and into the till.

STOP 11. D.W. Winkleman Pit
Examination of a nearly complete late Pleistocene stratigraphic section and discussion about mode of origin for the deltas.

Contorted varved red silts and clays
Contorted varved red silts and clays exposed in stream bank to left (N).

Road continues along 600 ft terrace

Note Onondaga Limestone outcropping.
This forms a ledge along the east wall of the valley.

Large sand and gravel pit
On left (W) is large sand and gravel pit excavated into kame terraces. To the right (E) is a thin veneer of sand and gravel over the limestone ledge.

Note broad bedrock flexures
Note broad bedrock flexures related to the stresses imposed during the Appalachian Orogeny (Chute, 1964).

B4: PUNCTUATED AGGRADATIONAL CYCLES (PACS) IN MIDDLE ORDOVICIAN AND LOWER DEVONIAN SEQUENCES II
Continuation of trip A8

STOP 4. Munnsville Quarry
Nine Helderberg cycles (PACS) are exposed in the Munnsville Quarry (Fig.9), four in the Olney-Elmwood, one equivalent to the Clark Reservation, four in the Jamesville and two (plus a partial cycle) in the Deansboro. The first four PACS contain restricted subtidal micrites grading upward into supratidal laminites. The four cycles in the Jamesville are defined by gradation from argillaceous limestones up into purer bioturbated limestones deposited in restricted subtidal conditions. The two complete Deansboro cycles, like those at Jordanville, grade from bioturbated shelf deposits.

STOP 5. Warlock-Perryville Quarry
The lower Helderberg Croup (Thacher-Jamesville) is well exposed at the north end of the quarry and the upper part (Jamesville-Deansboro) at the south end. Figure 10 is an outline of the stratigraphy of the lower Helderberg (north quarry face) with cycle analysis present up through the Clark Reservation. The section in the south quarry overlaps the top of the north section and within the complete Jamesville and Deansboro at least five cycles are present (Fig.11). Cycles IX and XI, the first and third Jamesville cycles, begin in bioturbated argillaceous calcarenite which grades up into cleaner more current-stratified calcarenites. Cycle X, is a stromatoporoid-laminite cycle like those seen early at Jordanville and Munnsville. Cycle XII, a thin current-stratified deposit bounded by two erosion surfaces, is genetically distinct. This cycle may represent the remains of a barrier, the lower erosion surface having been cut by a migrating tidal inlet, the upper by a ravinement.

B6: MOSS ISLAND, LITTLE FALLS, NEW YORK
H. S. Muskatt
Utica College
Utica, NY
"I consider this Island and its potholes so unique that I have recommended it most highly for inclusion in the registry of Natural Landmarks of the National Park Service. This island should not be touch in any way or the value of the potholes would be diminished" (Morisawa, 1977, p. G-41).
"Moss Island merits protection and preservation as a geological landmark." (Muller, Hawley, and Muskatt, 1977, p. G-8).
In May, 1976, Moss Island was declared a National Natural Landmark. It is one of only four hundred such registered natural treasures in the United States.
Plans for construction of a highway across Moss Island by the N.Y.S. Department of Transportation were initiated in 1968. Opposition to the proposed plan arose in 1973 only after some concerned individuals found out about those plans. In the forefront of that battle were the Mohawk Valley Floodplain Association, a local group concerned with the Mohawk River and the Utica chapter of the Izaak Walton League, a national conservation organization. These two organizations requested assistance from the New York State Geological Association in 1974. Through the efforts of these organizations, among many others, as well as individuals, national landmark status was achieved. Nevertheless, even with the granting of such status the N.Y.S. D.O.T. continued to press for construction over the Island. The D.O.T. stand was taken over the objections of such groups as the N.Y.S. Department of Environmental Conservation, National Park Service, Sierra Club. N.Y.S. Office of Parks and Recreation, and the National Audubon Society. Not until the Secretary of the U.S. Department of the Interior strongly recommended against approval of the application to the Coast Guard did the N.Y.S. D.O.T. "gracefully" back down. Disapproval by the Coast Guard was on environmental grounds.
GENERAL GEOLOGY
Moss Island (Fig. 1) is a 14-acre curved, dumbell-shaped feature lying between the Barge Canal to the south and the Mohawk River to the north. Generally the eastern part of the island is referred to as Moss Island. It lies on a horst which raised the Precambrian gneiss to its present position. The throw of the fault is considered to be about 850 ft (Cushing, 1905, p. 40). Isachsen and McKendree (1977) indicate a throw of 250 ft.
Bedrock of the island is a quartzose syenite gneiss of Precambrian age. Potholes and related hydraulic abrasion features, prominently displayed on the island, document the torrent of early postglacial drainage from the Great Lakes through the Mohawk Valley. For some 1000 yrs. from about 12,000 to 11,000 yrs ago (Lake Iroquois phase), the Mohawk River carried the entire outflow of the Great Lakes while the St. Lawrence valley was blocked by the slowly receding continental ice sheet. The resistant uplifted syenite gneiss here at Little Falls created the preglacial divide between the Hudson and St. Lawrence drainages. As the waters from the Great lakes poured over this divide the narrow valley at Little Falls was cut. These same rapid swirling waters helped create the spectacular potholes on the island. The potholes were reported first by Vanuxem (1842, p. 209).
2014: Highways are now totally different in Little Falls, so route has been adjusted.

View of Onondaga Valley
Looking W, straight ahead, view of Onondaga Valley, a N-S glacial trough.

View of downtown Syracuse on left.

Route I690 follows a glacial meltwater channel
Route I690 follows a glacial meltwater channel, the Erie Canal Channel. The floor of this channel is depositional (Muller, 1964, p. 51).

Route cuts through the Lake Iroquois glacial lake plain
Route cuts through the Lake Iroquois glacial lake plain whose outlet was at Rome, NY. This is part of the Ontario Lowland and is underlain by Middle and Upper Silurian units.

Northern limit of the Appalachian Plateau
View to the right (S), first good view of the northern limit of the Appalachian Plateau. Plateau units here are of Late Silurian age and principally the Vernon Formation and the Syracuse Formation, along the face of the scarp.

Ancient glacial lake barrier bars
Low ridges to right (S) and left (N) are ancient glacial lake barrier bars. Additional bars will be seen along route

Another view of Appalachian Plateau front on your right.

Outcrop of Middle Silurian Oneida Conglomerate
Outcrop of Middle Silurian Oneida Conglomerate, basal formation of the Clinton Group on your right (S) alongside roadway.

Another view of Appalachian front on right.

Recent Oneida Lake plain to left
Recent Oneida Lake plain to left (N) with view of the foothills of the Adirondacks in distance. Oneida Lake is a remnant of glacial Lake Iroquois.

View of the foothills of the Adirondacks ahead.

Riverside Airport on right (S).
2014: Airport is gone, but can still be seen on 1997 Google Earth photo.

UTICA on right.
My residence and the location of UTICA COLLEGE of Syracuse University.

Travel along a higher floodplain of ancient Mohawk River.

We are located in the Mohawk subprovince.
View to the right is again the northern limit of the Appalachian Plateau. The horizontal benches seen in the upper half of the scarp are of Middle Silurian sandstones and conglomerates of the Clinton Group. The Clinton Group disconformably overlies the mudstones and siltstones of the Frankfort Formation of lower Late Ordovician age which occur in the lower portion of the scarp.

View of the Adirondack foothills on the left (N).

Traveling on an old terrace of the Mohawk River.
Present Mohawk River floodplain seen on right (S).

Terraces cut into Middle Ordovician Utica Formation
View on left (N), terraces cut into Middle Ordovician Utica Formation to control slumping of slope. Every several years the shaley mudstone slumps, thereby blocking the highway for a day or two. Because of the regional dip, 50-80 ft/mi to the south (right), the Utica Formation is not exposed across the valley to the right (S). The overlying unit, the Frankfort Formation does crop out.

View on left (N), another exposure of terraced Utica shale.
Remington Arms plant on your right (S), in valley.

Terminal moraine of the Ontarian lobe
View across valley to right (S) of knobby hills representing the terminal moraine of the Ontarian lobe which moved from the west. This is the easternmost limit of the last glacial advance in this region (Dunn, 1960, p. D9).

A large gravel pit of glaciofluviatile origin.
View on the left (N). A large gravel pit of glaciofluviatile origin. The foreset beds are clearly shown. Being the top elevation of the deltaic deposit is about 520 ft, Fairchild (1912, p. 39) would assign it to post-glacial Lake Amsterdam.

Block of tillite on right (S).

Old stone Fort Herkimer Church on left (N)
Old stone Fort Herkimer Church on left (N) completed in 1767. Listed on National Register of Historic Buildings in 1972.

Glacial till on right.

View of Middle Ordovician Dolgeville Formation.
Look quickly down on right. View of Middle Ordovician Dolgeville Formation.

STOP 1. Outcrop of Late Cambrian Little Falls Dolostone.
This unit directly underlies the Black River Group in this area. It nonconformably overlies a Precambrian syenite gneiss. The nonconformable contact will be seen at Stop 2. The gneiss may be examined on Moss Island in Little Falls, Stop 5.
The Little Falls Dolostone is a sandy, medium-grained dolostone with some sandstones occurring near the base of the unit. Except for the abundant colonial algae Cryptozoon, the unit seems to be barren in this area.

Cliffs of Little Falls Dolostone on the right (E).

STOP 2: (15 min - picture stop).
Parking lot on left. Walk down hill (W) and cross road to
empty lot on west side of church. Walk to fence in back center of lot. Across abandoned railroad right-of-way observe non-conformable contact of Little Falls Dolostone overlying Precambrian syenite gneiss. Dolostone is overlain by classic manmade limestone wall.

STOP 3: (15 min -picture stop).
Park in clearing across the road, north side. CAUTION crossing road. Walk back across the road CAREFULLY. Observe potholes on northeastern end of Moss Island across Mohawk River. This view is similar to that shown in Lobeck (1939. p. 194). The potholes will be seen close up at Stop 5, our last stop on this trip.

St. Mary's Church on left.
Park on right, before turn, displays several small roches moutonnees.

STOP 4: (15 min picture stop).
In front of apartment house at 550 Alexander St. Large well-rounded boulder on front lawn was found in a pothole during excavation of the foundation of the building. This is a typical boulder used as an abrasion tool by the swirling waters for the creation of potholes.

STOP 5: End of trip.
Lock 17 is one of the highest lift locks in the world, 40.5 ft. The lower level is 322.5 ft above sea-level and the upper level is 363.0 ft above sea-level. For those who are interested, after we have examined the potholes, you can visit the old Erie Canal lock constructed about 1825. This old lock is located southeast of the existing Lock 17. It may be reached by walking across the catwalk in front of the eastern end of the lock and then down the stairs. The old Erie Canal lock is just a short walk to the east.
Part of the proposal involving construction of the bridge over Moss Island included covering the old lock. As stated by one local supporter of the bridge, "burying the old Erie Canal lock thus preserves this historic site for posterity".
Several potholes are located west of the parking area, along the south facing cliff adjacent to the road.
Walk north from parking area several yards along path to clearing, an old picnic area. Note iron rings in the gneiss. These rings are said by some to have been used as pole support tiedowns for: (1) telephone poles, (2) "A" frames as part of the lock construction, (3) eyelets for hawsers for hauling barges. Perhaps, on the other hand, they may have been used by Rip Van Winkle's friends as croquet wickets when they tired of bowling in the Catskills.
Walk NNW about 200 yds across the island and then turn N, downhill to potholes. STAY ON PATH and WATCH OUT for WIDE JOINT OPENINGS which require a slight jump. Paint marks represent bridge positioning.
The ecological balance here is critical, the soil cover is thin. DO NOT pick flowers or destroy foliage. Most of the low-lying bushes are blueberry bushes. You may eat in season. Most of the plant species seen here are characteristic of Adirondack flora.
Along most of the northeastern margin of Moss Island, facing the Mohawk River, numerous potholes occur. Although several hundred potholes are reputed to be scattered about the island the trip will observe only the area of greatest concentration. The deepest hole measured to the river silt-sand fill is 30 ft. The maximum diameter measured is about 20 ft.
USE EXTREME CAUTION while moving about. Please do not sit on THE THRONE.
The bedrock here is a quartzose syenite gneiss of Precambrian age. A number of quartz-rich dikelets cut across the relatively horizontal foliation of the gneiss. The dikelets generally strike east-west and dip 45°N. According to Cushing (1905), p. 15), the gneiss consists "mainly of feldspar, always show some quartz, usually from 5% to 15% of the rock in quantity, and usually have only a small content of dark minerals, magnetite, hornblende, pyroxene and black mica." The gneiss on the north side of the island is relatively fine-grained whereas on the south side, near the barge canal, it is more coarse-grained and in places seems to be porphyroblastic, occasionally showing augen structure. Several faults also are present.

B7: BIOSTRATIGRAPHY AND PALEOECOLOGY OF THE UPPER DEVONIAN ITHACA FORMATION NEAR CORTLAND, NEW YORK
Jonathan W. Harrington
Geological Consultant
Groton, New York
W. Graham Heaslip
State University College at Cortland
Cortland, New York
It is particularly appropriate that we examine the Ithaca Formation in the Cortland area during the Golden Anniversary Meeting of the New York State Geological Association. The rocks of this region are of considerable historical interest, having received attention since the earliest days of geological investigation in New York State. In fact, the presence of fossil shells in the Devonian rocks of New York was first noted in 1751 at a hillside outcrop in Cortland County by John Bartram, a member of the Lewis Evans Onondaga expedition (Wells, 1963).
The New York Devonian is unique in its completeness, fossil content. numerous outcrops, and relatively undisturbed nature. It is the standard reference section for North America and displays a classic example of facies transition. Stratigraphic and paleontologic investigation over the past century has produced a wealth of information, but "Despite this, perhaps another century of rigorous study will be required before a thorough understanding of its paleontology, lithology, stratigraphy and paleoecology can be attained." (Rickard. 1964).
The early stratigraphic work in the Upper Devonian of New York was done mainly by James Hall. J. M. Clarke. and H. S. Williams between 1840 and 1915. These workers subdivided the succession, described the faunas and attempted to correlate along the strike. Due to complex interfingering of the argillaceous western sequence with the thicker arenaceous eastern sequence, correlations proved difficult. Only in the 1930's with the work of Chadwick (1935) did it become apparent that the major facies had migrated across the basin of deposition as the Catskill Delta prograded.
Since 1942 investigation of the Upper Devonian has emphasized physical stratigraphy. The works of Sutton, J. F. Pepper, W. deWitt, Jr. and G. W. Colton have outlined the stratigraphy of the Senecan Series. The cyclic repetition of widespread black shales in western New York has been used to subdivide the succession. Paleontologic studies have, until recently, consisted of clarification and classification of forms originally described by Hall and Clarke between 1847 and 1915. The rarity of new discoveries testifies to the accuracy of their monumental works.

STOP 1. Outcrop in Homer Gulf on Rte. 41A
Ponticeras perlatum has been identified from exposures in Homer Gulf. This places the section in the lower portion of the Ithaca formation, probably correlative with the Renwick shale member. The lithology is extremely variable; consisting mainly of gray and reddish shales and siltstones. The fauna contains elements of both the Warrenella and Ithaca biotopes. Particularly common are: Conularia, Plumularia, Mucrospirifer, Hadrorhynchia, Cupularostrum eximia, Taxocrinus and linguloid brachiopods.

STOP 2. Roadcut on Rte. 13, just east of Dryden
This exposure in the lower Triphammer member is one of the most richly fossiliferous outcrops of the Ithaca formation. It contains abundant encrusting epifauna representing an admixture of biotopes, with incursions of the Ithaca biotope from the west and the Tropidoleptus from the east. Diversity is at a maximum, with maximum size development of Leiorhynchus mesacostale, Atrypa reticularis and Platyrachella mesastralis. Other common fossils are : Hadrorhynchia solon, Porcellia nias, Mucrospirifer posterus and Cyrtina hamiltonensis.

STOP 3. This locality will be an optional stop
The sequence of shales and siltstones is the source of several of the rarer fossils found in the Ithaca Formation, including the scyphomedusan, Plectodiscus cortlandensis and the trace fossil, Tomaculum problematicum.

STOP 4. Road cut on Rte. 81, 3 miles south of Cortland.
This exposure represents the Grammysia biotope in nearshore delta-front sands. Lithology is highly variable with shales, ripple-marked and cross-laminated siltstones and fine sandstones. Coquinite lenses, especially with Cupularostrum, are frequent and usually show distinct size-sorting and differential accumulation of valves. Areas of high currents are dominated by the infaunal filter-feeder, Grammysia, and the byssally attached bivalve, Goniophora. Occasional vertical burrows may be seen.
Sheltered areas support an abundant epifauna of crinoids (Decadocrinus and Acanthocrinus) and occasional brachiopods. This environment is characterized by the accumulation of plant fragments and orthoconic cephalopods, and by the high incidence of carnivores and scavengers -- the gastropods, Pleurotomaria and Loxonema, several asteroids (Urasterella, Lepidasterella) and ophiuroids.
The orientation of many of the smaller crinoid calices (inverted with free arms outspread) indicates very slight water agitation. However the preservation of fragile specimens such as asteroids and the scyphomedusa, Plectodiscus cortlandensis, required periodic rapid sedimentation. Fecal material is occasionally found at this outcrop. It has tentatively been identified as Tomaculum problematicum, a form not previously reported in North America.

STOP 5. Roadcut on Rte. 81 at Homer, Cortland County.
The sequence here consists of alternating dark shales and fine siltstones, occasionally ripple-marked. The sparse fauna, representing the Leptodesma or Grammsia biotope, consists of rare brachiopods and occasional crinoids Acanthocrinus). At several horizons there are colonies of the hexactinellid sponge, Actinodictya placenta. These fragile forms were almost certainly preserved in situ.
Small hillside quarries immediately north of this exposure have yielded Ponticeras perlatum, indicating a correlation with the lower portion of the Ithaca Renwick or Six-Mile Creek Members) in the Ithaca meridian.

JOINT ANNUAL MEETING OF NEW YORK STATE GEOLOGICAL ASSOCIATION
51st Annual Meeting
NEW ENGLAND INTERCOLLEGIATE GEOLOGICAL CONFERENCE
71st Annual Meeting
TROY, NEW YORK
October 5, 6, and 7, 1979
Gerald M. Friedman, editor
Hosts:
Rensselaer Polytechnic Institute
Troy, New York 12181
New York State Geological Survey
Cultural Education Center
Empire State Plaza
Albany, New York 12230
PREFACE AND ACKNOWLEDGEMENTS
It is a pleasure to welcome all of you to the joint annual meeting of the New York State Geological Association and the New England Intercollegiate Geological Conference. A fine program has been arranged for you. Two overlapping sessions have been planned for October 5, a full day Symposium on Sedimentary Strata and Tectonic Movements and concurrent workshops for earth-science teachers. Field trips have been scheduled for October 6 and 7 to classical sites of eastern New York State and adjoining New England. Have fun on your field trips.
I wish to extend my thanks to the authors and field-trip leaders for their contributions. Students and staff of the Department of Geology of Rensselaer Polytechnic Institute have given time and effort in preparing for this meeting. Credit for the success of this meeting goes likewise to the New York State Geological Survey, especially to R.H. Fakundiny.
Gerald M. Friedman, President

A1: DEVONIAN STRATIGRAPHY AND PALEOECOLOGY IN THE CHERRY VALLEY, NEW YORK REGION
State Paleontologist
N.Y. Geological Survey
N.Y. State Museum, State Education Department,
Albany, N. Y. 12234
PROLOG
In the northern parts of Otsego and Schoharie Counties, New York and bordering the southern margin of the Mohawk Lowlands and the northern margin of the Allegheny Uplands, is an exceptionally well exposed Early and Medial Devonian (400-365 million years old) sequence. These flat-lying sedimentary rocks record a broad spectrum of paleoenvironments. It is my intention to introduce you to the physical and organic makeup of these Devonian strata and to show how their combined characteristics enable a reconstruction of past environments and their associated role in the events of geologic history.

A1: DEVONIAN STRATIGRAPHY AND PALEOECOLOGY IN THE CHERRY VALLEY, NEW YORK REGION

Deformed Taconic Sequence rocks
Deformed Taconic Sequence rocks at bend of hill on right.

Crossing "Emmon's or Logan's Line"
Crossing "Emmon's or Logan's Line", the western limit of major Taconic gravity slides.

Guilderland; former site of glass manufacturing
Guilderland; former site of glass manufacturing, using sand from dunes atop Lake Albany clays.

Helderberg Escarpment in view to S (left)
Note terraces caused by differing horizontal limestone formations.

Climbing hill of eroded fault scarp
Southern extension of easternmost of Mohawk Valley normal faults.

Middle Ordovician Schenectady sandstone and shale
Middle Ordovician Schenectady sandstone and shale exposures scattered and small from here to Sloansville.

Crossing Schoharie Creek

Schoharie Creek parallels US 20 on S(left).

Schenectady sandstone and shale on hill
Several exposures of Schenectady sandstone and shale on hill at west end of Sloansville.

Region now underlain by Silurian and Devonian strata.
Passing from region underlain by Middle Ordovician strata to region underlain by Silurian and Devonian strata.

Karst topography
Karst topography; sink holes on N & S of US 20 in Lower Devonian Manlius and Coeymans Limestones.

Long exposure of Onondaga Limestone
Long exposure of Onondaga Limestone on S(left), showing Moorehouse Member with 2 m of Nedrow Member at W end.

Roadcuts in Kalkberg Limestone
Roadcuts on both sides of US 20 in Kalkberg Limestone; about 2m of New Scotland argillaceous limestone at top of exposure.

Kalkberg Limestone forms conspicuous terrace
Roadcuts on both sides of US 20 in Kalkberg Limestone; forms conspicuous terrace.

Roadcut on S(left) of Esopus Shale
Roadcut on S(left) of Esopus Shale, deformed by glacial shoving(?).

Cherry Valley hills to S(left).

Exceptional landscape view to N(right)
Exceptional landscape view to N(right) across Mohawk Valley farmland floored with Ordovician and Upper Cambrian strata; Proterozoic gneisses of Adirondack Mountains in distance.

STOP 1. Chittenango, Cherry Valley ls, Union Springs shale
Parking area on right shoulder beyond W end of exposure. Roadcut on S (left) of road.
Three Middle Devonian units of Marcellus Formation of the Hamilton Group are well displayed here: Chittenango Shale (topmost), Cherry Valley Limestone, Union Springs Shale.
The dark gray-black Chittenango Shale contains the small, needle-like fossil Styliolina fissurella believed to have been pelagic in habit. No proven benthonic fossils have been found in the Chittenango. The hard, massive Cherry Valley limestone has yielded several species (Rickard, 1952) but they are scarce and exceedingly difficult to extract. Nautiloid and goniatite cephalopods are diagnostic, chief of which are Striacoceras and Agoniatites vanuxemi. The Union Springs Shale has a few thin limestone beds in its upper few feet which contain horn corals, trilobites, ostracodes, pelecypods, lingulid brachiopods, and the small goniatite Werneroceras plebeiforme, extremely useful for correlation purposes.
Of especial interest here are some unexplainable structural oddities in the Union Springs. One is the "pseudo-cleavage" and the other is the disrupted limestone concretions. These features may be manifestations of a large westward decollement, created during the Acadian Orogeny in Early Erian (Early Cazenovian) time as continental plate overriding (or under-riding) produced a temporary basin on the site of the Devonian carbonate shelf in which black muds accumulated. Whatever their causes, these are anomalous structures in otherwise virtually structureless strata.

Roadcut in Otsego Shale on N (right) side of road.
Cherry Valley hills capped by younger Solsville sandstone and shale whereas Otsego forms slopes and Chittenango floors the intervening valleys.

Onondaga (Moorehouse) Limestone on S(left) of road.

Road ditch on W(left) shows Nedrow shaley limestone.

STOP 2. Moorehouse Member of Onondaga Limestone
The roadcut on the E(right) shows the Moorehouse Member of the Onondaga Limestone; the Nedrow Member may be examined by walking back to the ditch exposure on the west side of NY 166.
A little over 60' of medium to thick bedded, dark to medium gray, fine to medium grained limestone with bedded and nodular dark gray to black chert is well shown. The unit is not overly fossiliferous although brachiopods, bryozoans, and pelmatozoan debris may be collected.
By contrast, the Nedrow is a thin to medium bedded, shaley, argillaceous limestone which weathers lighter. Platyceratid gastropods are diagnostic.

STOP 3 (30 minutes)- Park off highway on right shoulder.
The roadcut on the E(right) shows the Edgecliff Member of the Onondaga Limestone resting with sharp lithologic contact on the Carlisle Center calcareous, silty mudstone.
About 15' of massive, irregular bedded, light to medium gray, medium to coarse grained Edgecliff Limestone with tan to light gray nodular to bedded chert and with prolific corals (often silicified ) and crinoidal debris is splendidly exhibited here. The lower 4' is non-cherty and finer grained and the basal few inches contains angular shale fragments. The contact with the subjacent Carlisle Center is abrupt and a marked lithologic change.

Carlisle Center in sharp contact with Esopus Shale on E(right).

Kalkberg Limestone on E(right).

Kalkberg limestone, chert, and shale on S (right).

Long, high roadcut on S (right) -
Will be visited later as Stop 6.

STOP 4. LUNCH (40 minutes )
Slope underlain by Union Springs Shale capped by terrace of Cherry Valley Limestone (now completely grassed over); excellent view to N across Mohawk Valley to Adirondack Mountains in distance.

Roadcut on N (right) in Onondaga (Moorehouse) Limestone.

Good view to N(right).

28' of Upper Coeymans (Deansboro) Limestone
Roadcut on E(right) shows about 28' of Upper Coeymans (Deansboro) Limestone with great profusion of gypidulid brachiopods, often silicified, and crinoid debris. Few chert nodules signify stratigraphic nearness of overlying Kalkberg Limestone.

16' of upper Manlius Limestone.
Roadcut on E (right), now largely concealed, of about 16' of upper Manlius Limestone.

STOP 5 (40 minutes) - Park on E(right) shoulder.
Long, high roadcut on E (right) in Lower Coeymans (Dayville), Manlius (Thacher), and Rondout (Chrysler). Thicknesses of each are 50', 44' and 12', respectively. Orange paint mark shows Coeymans/Manlius contact. Note that there is no reef rock in the uppermost Manlius nor Tentaculites- bearing ribbon limestones in lowermost Manlius in this section (compare with more easterly Manlius at Stop 7).
Coeymans and Manlius are distinguished in that the former is lighter gray, thicker or irregularly bedded, coarser grained, and breaks with an irregular fracture; here, it is more fossiliferous than the underlying Manlius and has crinoidal debris and larger brachiopods. There is a 4' dolomitic shaley zone 25' from the base of the Manlius which is somewhat gradational into the subjacent Rondout Dolostone.
The Manlius here is less fossiliferous than to the east and its environment may have been somewhat more saline so as to be less conducive to normal marine invertebrates.

Roadcuts on both sides of NY 166 in Kalkberg Limestone.

STOP 6. (40 minutes) Park off highway on right shoulder.
Long, high roadcut on S (right) in Kalkberg, Oriskany, Esopus, Carlisle Center, and Onondaga Formations. - Park off highway on right shoulder. Beginning at the overpass for the abandoned Cherry Valley Railroad, and midway within the Kalkberg Limestone, is a 1-3 cm sticky clay bentonite (volcanic ash) which has been radiometrically dated (Miller and Senechal, 1965), using Rb-Sr isotopes, as 39S million years old. Note the regularity of the thin to medium bedded siliceous limestones, the shale intercalations, and the dark gray to black chert beds and nodules, as well as the great profusion and diversity of brachiopods and bryozoans.
The next overlying unit is a famous one in New York stratigraphy -- the Oriskany Sandstone. Its fame as a gas producer has long been known in central and western New York. Here, however, it is a quartzose limestone with large, rounded, sand grains of quartz in a calcite matrix. The contact with the Kalkberg is a "welded " one.
Seventeen feet of chertified argillite, chert, and dark gray shale make up the overlying Esopus Formation, here. Eastward, in the Hudson Valley, the Esopus reaches a thickness of over 300'. In sharp contact is the next overlying Carlisle Center Formation. This is a curious unit lithologically and paleontologically. Physically, it consists of about 45-55% clay minerals, 25-30% quartz of silt size, and 25-30% calcium carbonate. Organically, it is replete with only one trace fossil, the worm feeding trail, Zoophycos (Taonurus) caudagalli. Its environment of deposition is a puzzle!
The Edgecliff Member of the Onondaga Limestone rests with a marked lithologic and paleontologic change on the Carlisle Center mudstone. This and other units of the Onondaga have been previously described and observed at Stops 2 and 3. Note the green mineral staining, attributed as glauconite, along the contact.

Seneca Ls Mbr of Onondaga on N (left).
Roadcut in Seneca Limestone Member of Onondaga on N (left).

Roadcut in Seneca Limestone on S(right).
During highway construction, this showed an abrupt lithologic contact with the overlying Union Springs black shale. Note the Cherry Valley Limestone terrace above.

Seneca Limestone and Tioga Bentonite
Roadcut on S(right) in massive, dark gray Seneca Limestone with re-entrant at base showing 8-13 cm of sticky, light gray clay,--the Tioga Bentonite.

Chittenango-Cherry Valley-Union Springs Members
Long roadcut in Chittenango-Cherry Valley-Union Springs Members of the Marcellus Formation (STOP 1)

Karst topography region
Sink holes on W (left) about 400' from road.

Coeymans and upper Manlius limestones
Continuous ledge of lower Coeymans and upper Manlius limestones parallels road on S (right).

STOP 7. (45 minutes) -
Buses will unload passengers on left shoulder opposite roadcut and load at right bend, 0.1 mile to the SE.
Roadcut in Manlius (Thacher Member) Limestone on S (right) side. Thin-bedded (ribbon) limestone, fine grained, dark gray to black, weathers very light gray. Rock breaks with a "ringing" sound and conchoidal fracture. Numerous shale intercalations. Bedding planes covered with the extinct mollusk, the narrow conical Tentaculites gyracanthus, the ostracode Hermannina alta, and the small spiriferid brachiopod Howellella Vanuxemi. Bryozoans and gastropods are occasionally found. In 1954 I was fortunate in discovering an horizon covered with the rare edrioasteroid Postibula n. sp.
Walk SE past abandoned farmhouse to next limestone ledge. Here, crossbedded coarse grained limestone occurs in the upper 18" of the ledge; this is a rare sedimentary feature in the Helderberg Group. Proceed W across field to next limestone ledge. This is a stromatoporoid reef, marking the summit of the Manlius Formation. The "cabbage-looking" unbedded limestone rests on regular bedded Thacher Limestone. These stromatoporoids acted as barriers blankets, and baffles and caused waves to break offshore creating differing environments of quite protected areas and agitated open areas.

Spectacular view ahead to the east
Spectacular view ahead to the east, looking across Hudson River Valley to Taconic and Berkshire Mountains in distance. Albany's Empire State Plaza is visible in the Valley.

Another excellent view to the east
Another excellent view to the east, in case you missed the earlier one!

A2: SEDIMENTARY ENVIRONMENTS AND THEIR PRODUCTS: SHELF, SLOPE, AND RISE OF PROTO-ATLANTIC (IAPETUS) OCEAN, CAMBRIAN AND ORDOVICIAN PERIODS, EASTERN NEW YORK STATE
Gerald M. Friedman
Troy, New York 12181
My thanks are extended to my student, friend, and colleague Brian D. Keith with whom I enjoyed collaboration in the study of the rocks of the Taconic Sequence. Parts of this guide are an abbreviated version of our papers Keith and Friedman (1977, 1978).
On this field trip, instead of tracing formations, we shall study sedimentary facies. We plan to hop from the products of one environment to those of another. At each exposure we shall study the rocks in terms of lithology, geometry, sedimentary structures, and fossils, and concentrate on the pattern of deposition which created the facies that we shall examine. Remember that the various exposures of Cambrian and Ordovician rocks to be visited are not time correlative. Each field stop will stand on its own; facies analysis will proceed within the boundary conditions of a single exposure. On this field trip the name of the formation becomes secondary; hence this field trip has been designed irreverently; it pays no heed to formation boundaries.
The fascination of the area around R.P.I. is its diversity of sedimentary geology: in one day of field trips we can examine sedimentary facies of Cambrian-Ordovician age which originated in shallow as well as in deep marine waters. Few other areas can match this diversity of sedimentary facies. The geologic coincidence for this diversity of sedimentary environments in the area of the R.P.I. Campus is its unique location: from Early Cambrian through Early Ordovician R.P.I. would have been on a carbonate shelf. Between Early Cambrian and Early Ordovician times the shelf to basin transition was east of Rutland, Vermont. Tectonic movements shoved Cambrian and Ordovician rocks of slope, rise, and basin facies across the shelf facies so that today the exposures on and near the campus of R.P.I. are basin or basin margin (rise) facies with shelf facies of Cambrian and Ordovician age occurring to the west (Friedman, 1972) (Fig. 1).
During Cambrian-Ordovician time, most of the North American continent was a shallow epeiric shelf sea, like the present-day Bahama Bank. At the eastern edge of this shallow sea, i.e. at the eastern edge of this continent, a relatively steep slope existed down which carbonate sediment moved by slides, slumps, turbidity currents, mud flows, and sand falls to oceanic depths to come to rest at the deep-water basin margin (rise), where a shale facies was deposited (Sanders and Friedman, 1967, p. 240-248; Friedman, 1972, p. 3; Keith and Friedman, 1977, 1978; Friedman and Sanders, 1978, p. 389, 392). Shale also formed much of the basinal facies in the deep water beyond. Because allochthonous transport has been inferred for large blocks of rocks presently exposed on and near the R.P.I. Campus, the evidence on the ground shows that the campus is the site of Cambrian and Early Ordovician rocks of basin margin (rise ) and deep basin facies (shales deposited in the Middle Ordovician (Schenectady ) west of Campus are autochthonous basin facies). Thus deep-water basin margin (rise) and basinal facies can be visited on and near the R.P.I. Campus, whereas to the west carbonate shelf facies are exposed that are analogous to those of the west shore of Andros Island on the Great Bahama Bank (Fig. 1). The paleoslope was probably an active hinge line between the continent to the west and the deep ocean to the east, similar to the Jurassic hinge line of the eastern Mediterranean between carbonate shelf facies and deep-water shales (Friedman, Barzel, and Derin, 1971). Such hinge lines in the early geosynclinal history of mountain belts are fixed by contemporaneous down-to-basin normal faulting (Rodgers, 1968, quoting Truempy, 1960), as probably occurred with the rocks of the area near R.P.I. Later thrusting to lift the deep-water facies across the shelf facies along hinge-line faults resulted in the contiguity of the two facies. This later displacement was so great that the Cambrian and Early Ordovician deep-water sediments were shifted far west of their basin margin.
This field trip has been divided into two parts, each part corresponding to half a day. In the morning and early afternoon we shall study facies of deep-water origin and in the late afternoon those of shallow epeiric origin. Each of the two depositional settings will now be explained.

A2: SEDIMENTARY ENVIRONMENTS AND THEIR PRODUCTS: SHELF, SLOPE, AND RISE OF PROTO-ATLANTIC (IAPETUS) OCEAN, CAMBRIAN AND ORDOVICIAN PERIODS, EASTERN NEW YORK STATE

STOP 1. EXPOSURE ON EAST SIDE OF U.S.9
(across from a white house) (SECTION SOUTH OF HUDSON)
Figure 12 shows and describes the lithofacies exposed at this stop, and interprets its depositional setting. The rocks are of deep-water mid-fan origin (Figs. 1 and 10), Note especially the interesting "hemipelagic" interbeds of fine-grained limestone (micrite) and dark shale (Fig. 8) and the carbonate-clast conglomerate (Fig. 4). Read carefully the material covered under the heading of "Deep-Water Setting: a Slope-Fan-Basin-Plain Model" so that you understand the objective of making this stop.

STOP 2. JUDSON POINT
Figure 13 illustrates the section seen at this stop and describes the lithofacies; it also provides an interpretation of the depositional setting. The rocks are of inner- to mid-fan origin (Figs. 1 and 10). The section is dominated by turbidite beds, and several massive coarse sandstone beds. The presence of several AE beds of the Bouma Sequence is characteristic of proximal turbidites. The occurrence of thick massive sands and local conglomerates and thin-bedded laminated sands suggests channel and levee deposits of the inner fan area. Two of the conglomerates are somewhat lenticular and truncate an underlying bed, suggesting channel deposition. Again review the section entitled "Deep-Water Setting: a Slope-Fan-Basin-Plain Model" for a better understanding of the features observed at this stop.

STOP 3. NUTTEN HOOK
Figure 14 gives details on this section, including an interpretation of depositional environment.

STOP 4. EXPOSURES SOUTH OF SCHODACK LANDING
Bus parks on dirt road east of highway. We shall first examine the road cut on the east side of the highway and then walk on dirt road across the railroad tracks to view more fine exposures.
Figure 15 describes and illustrates the section seen and provides interpretation of the depositional setting. Note exposures of bedded micrite with shale partings. This micrite represents lime mud which was derived from the shelf and probably settled from suspension. The conglomerate overlying the bedded micrite is probably the result of slumping, since the clasts appear to be derived from the underlying limestone beds. The strata at this stop show mid-fan development and possibly an inner fan channel as well. Again review the earlier section entitled "Deep-Water Setting: a Slope-Fan-Basin-Plain Model" for additional interpretation of depositional setting.

STOP 5. RPI '87 Gym. Exposure behind fence adjacent to gym.
Ruedemann (1930, p, 114; also fig. 64) described and photographed this exposure as a good example of a "cliff of mylonite," one of the "excellent exposures of a fault breccia" on the campus of Rensselaer Polytechnic Institute. According to Ruedemann and reconfirmed by Elarn (1960) a thrust fault follows part of this street (Sage Avenue) and Ruedemann mistook this conglomerate for a fault breccia. Perhaps the presence of criss-crossing veins in this exposure led to his interpretation of a "cliff of mylonite." Jack G. Elarn (1960; unpublished Ph.D. thesis at Rensselaer Polytechnic Institute) assigned the rocks at this exposure to the Schodack lithofacies of Early Cambrian age. Cushing and Ruedemann (1914, p. 69) had introduced the "Schodack Formation" which according to Fisher (1961, p. D8) has now fallen victim to a nomenclatorial "snafu." Zen (1964) has renamed this formation the West Castleton Formation.
Lowman (1961) recognized that the boulders are a conglomerate and not a breccia, and following Kuenen and Migliorini (1950), he introduced the term brecciolas. The term brecciolas refers to graded limestone breccia beds that alternate with dark-colored shales (Lowman, 1961, p. B6; Sanders and Friedman, 1967, p. 242; Friedman, 1972, p. 25; Friedman and Sanders, 1978, p. 390, 395).
The limestone- sandstone- and chert boulders which are embedded in shales at this exposure range from angular to rounded and show considerable variation in size (Fig. 5). Some boulders are coarse-grained fossiliferous limestone fragments with a micritic dolomite matrix. The rocks above the brecciolas are greenish-gray shales.
The boulders are those of rocks that formed under shallow shelf conditions. Their emplacement as boulders into shales, which are considered to be offshore deep-water sediment, indicates that the boulders moved downslope. The environment of deposition inferred for the brecciolas at this stop is that of the lower slope or base of slope (Fig. 1). Although the boulders came from the west down the slope, shelf carbonates (their source) extend many miles east of Troy (and presumably underlie Troy at depth).
Brecciolas which formed along the original east edge of the carbonate shelf parallel to the depositional strike for hundreds of miles define the site of the basin margin (rise) in Cambrian-Ordovician time. This Cambrian-Ordovician basin margin was located east of Troy near the present site of the Green Mountain axis. A relatively steep slope must have existed between the shelf edge and the basin margin with resultant instability that helped initiate slides, slumps, turbidity currents, mud flows, and sand falls.

STOP 6. TROY HIGH SCHOOL QUARRY
The spectacular brecciolas at this exposure consist of three members with eleven sub-members (Lowman, 1961). For details of the rocks, refer to Lowman's descriptions (1961, p. Bll-Bl2). The brecciolas are Schodack lithofacies of the West Castleton Formation of Early Cambrian age, as at Stop 5. Note that the carbonate shelf west of Troy contains no rocks older than Late cambrian; somewhere between west of Troy and the present Green Mountains the Middle Cambrian (?) and Lower Cambrian strata wedge in.
A thin-section study shows the limestones to consist of biomicrites, biointramicrites, and micrites with varying terrigenous quartz and clay minerals. The intraclasts are of pelmicrite. Shell fragments have been selectively dolomitized.
The observation that the limestone boulders are mostly micrites indicates that before removal downslope from their site of deposition the limestones were deposited under low-energy conditions on the shallow shelf to their original west, but at a place now still far to the east of Troy. The abundant fauna shows that the shallow waters were well aerated. The carbonate sediments must have lithified before their displacement downslope.

STOP 7. TROY JEWISH COMMUNITY CENTER
One large block of orthoquartzite, approximately 30 feet by 15 feet, probably settled in deep-water shale. Although limonitic, this orthoquartzite is devoid of rock fragments, hence is a second-cycle or multicycle rock. Note that the exposed shales surrounding this erratic block show that this block occurs singly. This exposure occurs along strike of the brecciolas and many more exposures of the brecciolas occur north of here in Frear Park. In a pit about 100 feet or so north of this block we exhumed from the shale a block of dark gray, fractured and veined micritic dolomitic limestone.
The size and shape of the block of orthoquartzite suggests more than a steep slope. To detach a block of this dimension required considerable instability near the shelf edge, such as severe shakes as occur during earthquakes. This block of rock differs in litho logy from the brecciolas which we have seen at the previous two stops. In contrast to the flat limestone boulders of the previous stop this huge block with its irregular outline suggests that solid bedrock of sandstone was forcibly detached from the shelf edge or basin slope. By analogy with modern events, turbidity currents, slumps, mud flows, and slides are usually funneled through submarine canyons. Could it be that this block was part of the wall of a submarine canyon which became detached during one of the slides and was moved by gravity into the basin or basin margin?
The alternative interpretation would be to consider this block to have been caught up in fault movement. Indeed slickensides are present on this block. However, the lower exposed contact with the shale is depositional and not faulted. Because the orthoquartzite block occurs along strike with the other brecciolas, and a limestone block has been found about 100 feet away, the evidence suggests that emplacement was by gravity rather than by faulting.
Convince yourself that this block is not a glacial erratic.
The shales at this stop have been assigned to the Schodack lithofacies of the west Castleton Formation of Early Cambrian age; the displaced orthoquartzite block may be as old as Precambrian.

Exposures of westernmost deep-water sedimentary facies
Note two exposures of westernmost deep-water sedimentary facies, consisting of Middle Ordovician Normanskill graywacke and shale, in roadcut on right (northbound lane). West of here and underneath the Normanskill at a depth of several thousand feet are Cambrian-ordovician rocks of shelf facies.

This beautifully designed bridge won an award in 1958.

STOP 8. LESTER PARK
This locality is the site of one of the finest domed algal mats to be seen anywhere preserved in ancient rocks. On the east side of the road in Lester Park a glaciated surface exposes horizontal sections of the cabbage-shaped heads c0mposed of vertically stacked, hemispherical stromatolites. These structures, known as Cryptozoons, have been classically described by James Hall (1847, 1883), Cushing and Ruedemann (1914), and Goldring (1938); an even earlier study drew attention to the presence of ooids as the first reported ooid occurrence in North America (Steele, 1825). Interest in these rocks has been revived as they are useful environmental indicators (Logan, 1961; Fisher, 1965; Halley, 1971). The algal heads are composed of discrete club-shaped or columnar structures built of hemispheroidal stromatolites expanding upward from a base, although continued expansion may result in the fusion of neighboring colonies into a Collendia-type structure (Logan, Rezak and Ginsburg, 1964). The stromatolites are part of the Hoyt Limestone of Late Cambrian (Trempealeauan) age. An intertidal origin has been inferred for these stromatolites.
The evidence for deposition under tidal conditions for the Hoyt Limestone at Lester Park includes: (1) mud cracks, (2) flat-pebble conglomerate, (3) small channels, (4) cross-beds, (5) birdseye structures, (6) syngenetic dolomite, and (7) stromatolites (for characteristics on recognition of tidal limestones, see Friedman, 1969).
At Lester Park the heads which are circular in horizontal section range in diameter from one inch to three feet; many are compound heads. The size of the larger heads suggests that they formed in highly turbulent waters.
The line of depositional strike along which the domed stromatolites occur was probably where the waves were breaking as they came across the deeper ocean from the east and impinged on the shallow shelf.
Several petrographic observations in these rocks permit an analogy with modern algal mats in hypersaline pools of the Red Sea Coast (Friedman and others, 1973). Mat-forming algae precipitate radial ooids, oncolites, and grapestones which occur in these rocks; interlaminated calcite and dolomite which in part compose the stromatolites of the Hoyt Limestone correspond to alternating aragonite and high-magnesian calcite laminites which modern blue-green algae precipitate. In modern algal mats the high-magnesian calcite laminites contain abundant organic matter in which magnesium has been concentrated to form a magnesium organic complex. Between the magnesium concentration of the high-magnesian calcite and that of the organic matter sufficient magnesium exists in modern algal laminites to form dolomite. Hence the observation in ancient algal mats, such as observed in the Hoyt Limestone, that calcite and dolomite are interlaminated, with calcite probably forming at the expense of aragonite and dolomite forming from high magnesian calcite.

Pass basal Paleozoic quartz-cobble conglomerate
Pass basal Paleozoic quartz-cobble conglomerate (a possible talus deposit) on weathered Precambrian gneiss

STOP 9. FORT HUNTER QUARRY
Stromatolites in the Fort Hunter Quarry consist almost entirely of dolomite in the form of irregularly bedded, finely-laminated, undulating structures (Figure 9). The rocks in this quarry are part of the Tribes Hill Formation of earliest Ordovician age (Fisher, 1954). The lithofacies of the Tribes Hill formation have been studied in detail by Braun and Friedman (1969) within the stratigraphic framework established by Fisher (1954). Figure 10 is a columnar section showing the relationship of ten lithofacies to four members of the Tribes Hill Formation. At Fort Hunter we will study the lowermost two lithofacies of the Fort Johnson Member (see column at right (east) end of section, in Fig. 10).
Two lithofacies are observed: (1) lithofacies 1, mottled feldspathic dolomite (Figure 10), and (2) lithofacies 2,. laminated feldspathic dolomite. Lithofacies 1 is at the bottom of the quarry, and lithofacies 2 is approximately halfway up.
Lithofacies 1
This facies occurs as thin dolostone beds, 2 cm to 25 cm but locally more than 50 cm thick, with a few thin interbeds of black argillaceous dolostone which are up to 5 cm thick. In the field, the dolomite shows gray-black mottling and in places birdseye structures. In one sample, the infilling of the birdseyes shows a black bituminous rim which may be anthraxolite. In the field, trace fossils are abundant, but fossils were not noted. Authigenic alkali feldspar (microcline) is ubiquitous throughout this lithofacies; its identity as alkali feldspar was determined by Xray analysis and staining of thin sections with sodium cobaltinitrite. The insoluble residue makes up 22 to 54% by weight of the sediment in samples studied with most of the residue composed of authigenic feldspar. An iron-poor yellow sphalerite may be occasionally found in the rocks of this lithofacies.
Lithofacies 2
This lithofacies is mineralogically identical to the previous facies but differs from it texturally and structurally in being, irregularly bedded and in containing abundant undulating stromatolitic structures ("pseudo-ripples"), as well as disturbed and discontinuous laminae. In places there are a few thin interbeds of black argillaceous dolostone. The thickness of the laminites of this facies ranges from 1/2 mm to 2 or 3 mm; on freshly broken surfaces the color of the thinner laminae is black and that of the thicker ones is gray. The insoluble residue, for the most part composed of authigenic feldspar, constitutes between 35% and 67% by weight in samples studied.
These two lithofacies which form the basal unit of the Ordovician, were formed on a broad shallow shelf. Stromatolites, birdseye structures, scarcity of fossils, bituminous material, syngenetic dolomite, authigenic feldspar, and mottling suggest that these rocks were deposited in a tidal environment (Friedman, 1969). Based on analogy with the carbonate sediments in the modern Bahamas, Braun and Friedman (1969) concluded that these two lithofacies formed under supratidal conditions. However, in the Persian Gulf flat algal mats prefer the uppermost intertidal environment and along the Red Sea coast they flourish where entirely immersed in seawater, provided hypersaline conditions keep away burrowers and grazers (Friedman and others 1973). Hence on this field trip we may conclude that the stromatolites indicate tidal conditions without distinguishing between intertidal and supratidal. For more details on these lithofacies refer to Braun and Friedman (1969).

Cross original Erie Canal, built in 1822.
Amos Eaton surveyed this route at the request of Stephen Van Rensselaer; after this survey Amos Eaton and Van Rensselaer decided to found a school for surveying, geological and agricultural training which became Rensselaer Polytechnic Institute.

Fulton-Montgomery Community College

STOP 10. TRIBES HILL QUARRY
Route of Walk
Take the trail toward old abandoned crusher, but instead of heading toward the quarry move uphill to the first rock exposures. The rocks to be examined are near the edge of steep cliff.
Description and Discussion
In the rocks at this exposure the field relationships show typical channels truncated at their bases. Lodged within the channels are limestone blocks of variable shape ranging in diameter from about one to three feet. These blocks resemble similar blocks in tidal channels of the Bahamas which are derived by undercutting of the banks of the tidal channels. The blocks at this exposure are rounded, suggesting that they have undergone some transport.
The rocks composing the channel (the channel fill) and the blocks of rock within the channels have been described as lithofacies 8 (channel fill) and lithofacies 7 (blocks) of the Wolf Hollow Member of the Tribes Hill Formation (lowermost Ordovician) (see columnar section of Fig. 16); column at right end of the section) (Braun and Friedman, 1969). The channel fill (lithofacies 8) consists of intrasparite and biointrasparite with sporadic ooids, a high-energy facies, whereas the blocks (lithofacies 7) consist of mottled dolomitic micrite and biomicrite, a low-energy facies of the undercut bank. The micrite blocks which foundered in the channels must have been indurated penecontemporaneously.
Hence during earliest Ordovician time high--energy tidal channels crisscrossed tidal flats at this site. In them water coming from the deep ocean to the east rose and fell with the changing tides.

A3: SEDIMENTARY ENVIRONMENTS IN GLACIAL LAKE ALBANY IN THE ALBANY SECTION OF THE HUDSON - CHAMPLAIN LOWLANDS
Robert J. Dineen and William B. Rogers*
New York State Geological Survey
The history of Lake Albany has intrigued glacial geologists since the turn of the century. The simple, single-stage lake of Peet (1904) soon was modified by Woodworth (1905) to a two-stage model where varved Lake Albany clay is overlain by sand of Lake Quaker Springs. Later workers, up to the present time, have defined more lake stages using the elevations of beaches, deltas, and terraces and by the character of the deposits of each lake stage. Stratigraphic sections revealed in new exposures and test borings have permitted the definition of sedimentary packages associated with each stage of Lake Albany. This field guide is a preliminary description of this new stratigraphy and provides the student with selected field stops that allow examination of the sediments.
The study area is in the mid-Hudson section of the Hudson-Champlain Lowlands (Fenneman, 1938). It lies between the Adirondack Mountains on the northwest, the Taconic Mountains on the east, and the Helderberg Plateau on the southwest (Fig. 1). The lowlands were deeply dissected by a southward drainage system prior to the Wisconsinan glaciation (Davis and Dineen, 1969). This drainage system consisted of the Colonie Channel and its tributaries - the Mohawk, Ballston, and Hudson-Battenkill Channels (Fig. 1). Only the Hudson-Battenkill channel is occupied by major drainage at present.
The Hudson Lobe of the Laurentide ice sheet occupied the lowlands during the Wisconsinan Glacial Stage. As the Hudson Lobe retreated, proglacial Lake Albany developed on the south. Lake Albany occupied the area from 15,000 to 12,600 y.b.p. (Connally and Sirkin, 1973). Drainage from the Great Lakes Basins entered this lake via the Mohawk River Valley (Stoller, 1911). The lake expanded from south to north as the Hudson Lobe retreated with the ice margin as the north shore of the lake (LaFleur, 1965b). The initial lake deposits were ice-contact sand and gravel that grade up into varved silt and clay (LaFleur, 1969, Dineen, 1979). Kame deltas developed when the ice margin hesitated during its retreat. Lake Albany extended 225 km from Newburgh to Glens Falls (Peet, 1904). Several large ice blocks were left behind by the retreating glacial lobe. The locations of the five ice blocks in the Albany area were the Hudson-Battenkill Channel near Selkirk (Dineen, in prep.), the Colonie Channel between Schenectady and Troy, at Round Lake, at Saratoga Lake (Hanson, 1977), and the Mohawk Channel at Schenectady (LaFleur, this volume). These ice blocks impeded sediment transport and controlled glacial and post-glacial drainage.

A3: SEDIMENTARY ENVIRONMENTS IN GLACIAL LAKE ALBANY IN THE ALBANY SECTION OF THE HUDSON - CHAMPLAIN LOWLANDS

The bluff to the east of the field house is a beach
The bluff to the east of the field house is a beach of +330 ft. Lake Albany (LaFleur, 1965a).

Cross the Hudson River on the NY 7 bridge.
We have driven down the east wall of the preglacial Hudson-Battenkill Channel. Test borings for the bridge and its approaches indicate that a - 20 ft. terrace underlies the floodplain in this area. A +40 ft. bedrock terrace underlies Watervliet to the west. The test borings indicated that only a thin layer of till underlies the floodplain silty sands (J. Rumsey, N.Y.S. Dept. of Transportation, personal communication). The-20ft. bedrock terrace can be traced 12 miles south as far as Castleton and 3 miles north as far as Waterford.

Proceed up the west wall of the Hudson-Battenkill channel.

We have been driving along the interfluve
We have been driving along the interfluve between the Colonie Channel (west) and the Hudson-Battenkill Channel (east). Proceed down the hill into the Dephuskill Valley.

STOP 1. Wunderlich Pit (Fig. 5a)
This pit is in the Pollock Road kame delta. The ice margin was to the north. Meltwater built a kame delta into Glacial Lake Albany at the end of an esker complex, which lies north of the kame delta. Some clay lies draped over the eskers to the north, implying that the ice had melted away by the time of Lake Quaker Springs. The Section exposed in the pit is:
Top to 4m | Grayish brown sandy, silty, boulder till.
4 to 24m | Gravity and thrust-faulted, yellow- brown, planar cross-bedded, gravelly sand, with ripple laminae at the base and contorted laminae at the top.
24 to 30m | Trough cross-bedded, gravity faulted, sandy gravel
The basal gravel was deposited by southward-flowing water in an esker channel, the gravelly sand, in a kame delta. These beds grade southward into trough cross-bedded, silty sand. They are partially overlain by varved clay to the south. The till at the top was deposited during the Delmar Readvance.

We have crossed the east wall of the Colonie Channel.
A test boring in the channel along strike with the Loudonville esker contains large quantities of ground water under artesian pressure. Roger Waller measured a 12 m artesian head in that well (Dineen, Waller, and Hanson, in prep.).

We are now crossing dune sand
We are now crossing dune sand that mantles Lake Albany clay (Hanson, 1977). We are also crossing the west wall of the Colonie Channel.

Crossing Ballston Channel
We are on (and in) the Schenectady delta that the Mohawk River built into Lake Albany (Stoller, 1911). A test boring for I-890 penetrated 174 ft. of silty sand and 20 ft. of till without hitting bedrock.
Dunes are well developed in this area. Gastropods occur locally in sand just below the dune sand - lake sand contact.

The Schenectady well field is to the west.

STOP 2. DICKERSHAIDS PIT (Fig. 5b)
This pit is cut into the Schenectady delta. Its section consists of;
Top to 7.6m | light brown, trough cross-bedded, medium to fine sand with some gravel
7.6 to 20m | light brown, ripple-laminated, fine sand. Concretions are common in this zone
20 to 23m | yellow brown, varved silt and clay
Test borings to the east indicate that the clay extends to a depth of 230 ft. (Winslow and others, 1965).
The gravelly sands at the top of the pit are topset/fluvial beds that prograded eastward across the delta front sand, which in turn had prograded eastward across bottomset clay and silt. The sand is the source beds for the dunes that lie to the east (Dineen, Rogers, and Buyce, 1978).

We are traveling across the topset beds of the Schenectady delta.

Dunes are just starting to appear in this area.

Notice the small dunes to the left (northeast).
We are proceeding along a series of dune ridges.

STOP 3. SCICCHITANO PIT (Fig. 6a)
This pit shows dune, beach, and lake sediments (Dineen, 1977). The hill to the east is a dune-sand mantled drumlin. A compound dune cluster built up around the drumlin. Bedrock lies approximately 60 ft. below the surface, the Ballston Channel lies to the west. The drumlin stood as an island in Lake Albany, as the Schenectady delta built out into this area. A +330 ft. beach is exposed on the east side of the pit. It consists of a wave-cut platform, cut into till, overlain by a lag concentration of boulders and trough crossbedded, gravelly sand. Horizontal to ripple-laminated sand and silt were deposited offshore. Planar cross-laminated dune sand overlies the lacustrine deposits .
Parallel ridges with a NW-SE trend are the dominant form of dune crests in the Pine Bush sand plain, the name of the pine and oak brush covered sandy area between Albany and Schenectady. A secondary mode of dune form comprises crescentic ridges that are convex to the southeast. Ridges of this concentric type commonly join adjacent parallel ridges or form hooks curving to the southwest from the southeast end of a ridge. In the past, these crescentic dunes have been interpreted either as barchans (which suggests a southeast wind direction) or as parabolic dunes (which suggests a northwest wind). These interpretations were based on shape, directions of steeper slopes and linear trends. Recently, we have been able to settle this controversy with cross-bedding data, gathered from deep cuts made in the dunes during a recent flurry of construction projects throughout the Pine Bush area (Dineen, Rogers, and Buyce, 1978). Weathering and bioturbation have destroyed the primary sedimentary structures in the top three meters of the dune sand, so that a substantial excavation is required to expose undisturbed deposits that contain directional features. Measurements of over 200 cross-beds at 35 localities in the Pine Bush dunes give down dip modes to the northeast, southeast, and south. These data combined with the NW-SE trend of the linear ridges and the southeast convexity of the arcuate ridges indicate that the dominant dune-forming winds were northwesterly, hence the crescentic dunes are parabolic.
That southwest winds were also important is indicated by a prominent northeast mode in the dip directions. Fig. 6 of the dune crests shows the characteristic dune ridge pattern. Careful analysis of dune morphology, especially on aerial photos, shows the northeast side of linear ridges to have steeper slopes than the southwest side, and the southwest limbs of parabolic dunes to be atrophied. These observations corroborate the evidence for wind directions given by cross beds.
Only one measurement was recorded of a crossbed dipping toward the northwest quadrant, which indicates a nearly complete absence of dune-forming winds from the southeast during the post-glacial period.
The parabolic dunes have a relatively gentle convex upwind slope of <10° and a steeper concave downwind slope of >15°. They are transverse forms as opposed to the longitudinal ridge-forms.
The dune ridges in the Pine Bush are sinuous, generally parallel, and as much as two kilometers long. They are generally lower than the parabolic dunes.

STOP 4 OLD STATE AND NY 155 PITS (Fig. 6b)
Cross NY 155 and follow the dirt road eastward for approximately 0.3 mile: We have walked along the northeast limb of a parabolic dune. The blow-out hollow lies to the right. Sand blown from this hollow was deposited at the dune crest. Migration of these two features leave the limbs trailing, and produces the parabolic dune form. The southwest limb of this dune is subdued. The slipface of another dune lies to the right (south). Several small hollows can be seen along the inside of the limb that we are on. These are blowouts that formed recently due to tree throw or denudation of vegetation by fire. The taller trees are pitch pine, the low scrubs are dwarf or scrub oaks.
The pits to the northwest and west show aeolian cross-bedding in dune sand that disconformably overlies the lake sand. This dune is part of a large compound dune cluster. The dunes of the cluster are connected on their northeast limbs, which can be seen to the east of this dune crest. The connected northeast limbs form a continuous ridge that can be traced for over 3km.

Notice the till overlain by dune sand in the road cuts.

Some "dunes" are erosional forms
A sand pit just northeast of here showed trough crossbedded, gravelly, coarse sand. This gravelly sand underlies dune-shaped hills, implying that some "dunes" are erosional forms that have been wind-sculpted. The gravelly sand was probably deposited in a kame delta of the Delmar Readvance.

We are crossing the buried preglacial Mohawk Channel.
A drumlin field buried by lake sediment cuts across the channel (Dineen, 1975). The drumlin field is flanked on the west by a thick gravel blanket. The drumlins act as underground dams by impeding the west-to-east movement of ground water in the gravel blanket.

Crossing the Normanskill.
Climbing the south wall of the Mohawk Channel.

STOP 5. TOWN PIT (Fig. 7)
This pit is cut into the distal, kame delta portion of the Guilderland kame terrace. This stop, and stops 6, 7, 8 will illustrate the distal-to-proximal increase in labile (shale) lithic clasts, in angularity of clasts, and in clast size, that accompanies the decrease in sorting typical in a kame terrace. The Guilderland kame terrace was first mentioned by Woodworth (1905) when he observed the existence of a large gravel terrace northwest of Guilderland Center. He considered the terrace to be an ice marginal kame. LaFleur (1965b) called attention to glacial lake beaches that are cut along the northern margin of the kame. LaFleur also reported southwest dipping gravel and irregular beds of rhythmic clay in the kame. Woodworth (1905) and LaFleur (1965b) interpreted the kame as having been deposited by meltwater streams in an elongate hole in the ice. LaFleur (1965b) suggested that the streams were the outflow of Lake Amsterdam in the Mohawk Valley. Dineen (1975) found that the kame is continuous with a buried gravel blanket which extends north to Schenectady. The kame consists of well-sorted, sub-rounded, ice-contact sand and gravel to the east, and poorly-sorted, subangular, silty, bouldery sand and gravel to the west. The number of shale clasts and the overall grain size decrease from west to east. The surface of the kame slopes to the southeast, from +360 ft. at Stop 8 to +330 ft. at Stop 5. Stop 5 is in a kame delta that was built into Lake Albany, and shows planar cross-bedded, rhythmic silt and sand overlying trough cross-bedded, ice-contact sand and gravel. The rhythmites are overlain unconformably by planar-bedded, silty, cobbly sand that grades into clay to the southeast. These upper beds are delta foresets, and dip S20°E.

STOP 6. LEDO PIT (Figure 7)
Stop at entrance to pit and walk in. This pit contains large-scale, trough cross-bedded, cobbly, gravelly sand, dipping N20°E and overlying ripple trough cross-bedded, coarse sand. The cobbly sand grades upward into channels filled with rhythmic silt and clay. The channels trend N20°W. They are overlain by cobbly, silty gravel that is overlain by varved clay to the north.

STOP 7. OLIVER PIT (Fig. 7)
This pit contains planar cross-bedded, cobbly, sandy gravel that dips N80°E, and which overlies ripple-laminated coarse sand. These beds are overlain by pebbly, silty cobble gravel with channels filled with rhythmic silt and clay. Varved clay overlies the sequence to the north.
The lower gravel layers extend north of the kame, where they partially fill the Mohawk Channel; and they are overlain by lake deposits northward. They can be traced to Schenectady. This gravel probably was deposited on the ice block that occupied the Schenectady area during the early Lake Albany time (see LaFleur, this volume).
The channels that cut into the top of the gravel slope northeastward, perpendicular to the axis of the kame terrace .

STOP 8. WEST PIT (Fig. 7)
This pit contains poorly bedded, poorly sorted, shale-rich, silty, bouldery gravel, overlain by varved clay that fill erosional channels cut into the top of the gravel.

STOP 9 COLONIE COUNTRY CLUB PIT (Fig. 5a)
This is the Voorheesville delta. The access road runs along the foreset slope of the delta. The delta was deposited into early Lake Albany, and is at the distal end of the Meadowdale kame and outwash complex that was deposited by meltwater from a stagnant ice block in the Guilderland Center-Voorheesville area (Dineen, 1977). The section in the pit consists of planar bedded, ice-contact gravel and sand at the base, overlain by planar cross-bedded, foreset sand and gravel, which are overlain by topsets of trough cross-bedded, silty, gravelly sand. The Town of Voorheesville derives its water supply from the delta.

We are traveling up the foreset slope of the South Bethlehem delta.

STOP 10 TOWN PIT (Fig. 8b)
Park at the entrance to the access road and walk down into the gravel pit. The South Bethlehem deltas lie at +340, +300, +220, +190, and +170 ft. The +340 ft. delta is wholly contained within the Onesquethaw Creek Valley, and lies approximately 1 mile (1.6 km) west of Stop 10. The +300 ft. delta is the largest and best developed delta. The lower deltas prograde eastward across varved silt and clay. The +300 ft. delta was described as an ice- marginal kame delta by Woodworth (1905) and Cook (1930). Woodworth (1905) noted that the +300 ft. delta had a boulder and till covered, raised outer margin, with a southwest gradient. These features imply that the delta was deposited in the ice- contact environment. Air photo and field observations suggest that the +300 ft. delta's outer margin is not raised more than 2m (5 ft.). Exposures in gravel pits and along the Onesquethaw Creek reveal a predominance of fining-upward beds of coarse sand and gravel, and some lenses of boulders. These beds dip to the northeast at Stop 10, and to the southeast at Stops 11, 12, and 13. No till has been observed in the pits, but gravity faults are common west of a rock ridge in Stop 10, and in ice-contact gravel that is exposed in Stops 10, 12, and 13 . Boulders mantle the northeast slope of the delta along Rupert Road. Several channels cut southeastward across the delta's surface in the areas of Stops 10 and 12. Rhythmic silts and clays overlie the southeast and east margins of the delta (Stops 11 and 12). No kettle-holes were observed. A test boring 3500 ft. (1.3km) east of the delta showed a 70m (200 ft.) section of deltaic gravels interbedded with varved clay (Dineen, Waller, and Hanson, in prep.). The delta had been deposited in open ice-free water when the Onesquethaw Creek was carrying large quantities of very coarse sediment. The sediment was probably derived from a rapidly melting ice block that lay in the upper Onesquethaw Valley. The lower deltas were deposited in lower lakes by the Onesquethaw recycling the upper deltas. This stop (Stop 10) is at the apex of the +300 ft. Lake Albany delta. This pit shows normal-faulted, ice-contact, gravelly, coarse sand at the base. The sand is overlain by trough crossbedded, bouldery sandy gravel foreset beds. The foreset beds are overlain by trough crossbedded to structureless, silty gravel topset beds. The bouldery cross-beds indicate that this is the proximal section of delta.

STOP 11 SPAWN HOLLOW PIT (Fig. 8)
This pit is within planar cross-bedded, foreset beds of the central part of the delta. A thin section of topset beds is at the top of the pit. The exposed face shows the break in slope between the topset and foreset beds.

STOP 12. MALLOY PIT (Fig. 8b)
Notice that the delta foreset beds here are finer grained, and tend to be trough crossbedded rather than planar cross-bedded as they are at Stop 11. The topset beds are siltier and thicker than to the west.

STOP 13. CALLANAN PIT (Fig. 8b)
This pit is on the prodelta slope of the +300 ft. delta. Ice-contact sandy gravel lies at the base of the pit. This is covered by bottomset beds of trough cross-bedded, coarse sand. The bottomset beds are overlain by foresets of planar cross-bedded, coarse sand and gravel. Very silty, trough cross-bedded, topset gravels and varved clays cap the sequence.

STOP 14. WRIGHT PIT (Fig. 9a)
This stop shows lake silt and sand layers that were folded and faulted by ice shove during the Delmar Readvance. The section at this site consists of:
Top to 2.0m | yellow brown, varved clay and silt with laminae of fining upward, very fine sand. Layering is 6 cm thick. The sand is ripple to planar-laminated, the planar-laminae are at the base of the beds over fine lag gravel and a truncation surface.
2.0 to 3.3m | yellow brown, compact, ripple to planar-laminated, very fine sand with 0.5 cm laminae of clay. The sand fines upward. Bedding is faulted and folded, the fold axes trend Nl5°E and N80°E. The faulting is thrust up to the S40°W, soft sediment deformation is common.
3.3 to 3.7m | yellow brown, very fine sand with silt laminae. The varves fine-upward, and are 0.5cm thick. The varve sequence coarsens-upward to ripple-laminated sand, which fines-upward to varved silt.
3.7 to 4.7m | yellow brown, structureless, very fine sand, with contorted fragments of clay. Concretions are common at the base.
4.7 to 6.3m
gray brown, folded, very fine silt, clay, and fine sand in 5 to 20 cm thick coarsening-upward folded layers. The fold axes trend N60°E to N70°E. The tops of the folds are truncated and are covered by fining-upward, ripple cross-laminated, very fine sand.
6.3 to 13.3m | light gray, laminated silt.
Base of pit. | Test boring log:
13.3 to 32.5m | pinkish gray to light gray, varved silty clay.
32.5 to 35.4m | light gray, varved, slightly silty clay
35.4 to 39.0m | light gray, varved, sandy, silty clay
39.0 to 63.0m | gray, varved clay
63.0 to 79.2m | light gray, varved clay
79.2 to 82.0m
gray, soft, varved clay with a
trace (<5%) fine sand grading
down to sandy clay with subrounded
shale and quartzite
clasts
82.0 to 87.2m | Black shale.
The upper silty beds are folded parallel to the interfluve ridges that are present throughout the Delmar area. The upper part of the section was probably folded by the Delmar Readvance.

STOP 15. Kleinke Pit (Fig. 9a)
This pit is also developed in folded lacustrine silts and sands. The fold axes trend N40°E.
The section is:
Top to 0.8m | very light yellow brown, planar-laminated, very fine sand. A truncation surface is at 0.8m.
0.8 to 3.8m | yellow brown silt to medium sand that coarsens-upward. This unit is mostly ripple cross- laminated with climbing ripples at its base and top. Ripples climb to the S80°S and N80°W.
3.8 to 5.0m | yellow brown, structureless silt.
5.0 to 11.0m | yellow brown, folded and convoluted silt to very fine sand. Dewatering structures are common. The fold trends N40°E.
11.0 to 11.5m | yellow brown, contorted, varved sand, silt and clay.
11.5 to 13.5m | yellow brown, ripple-laminated, fining-upward fine sand to silt. Truncated and cemented at 11.5m.
This area was probably folded by the Delmar Readvance.

STOP 16. (Malloy) Loudonville Pits (Fig. 10b)
These pits are on the axis of the Loudonville esker complex. The Loudonville esker complex was described by Peet (1904) as a moraine-kame-delta complex that extended from North Albany to Newtonville. It is bounded on the north by a "boulder strewn" moraine ridge with elongate kettles (Woodworth, 1905). The esker system slopes to the south, with coarser gravels and cobbles to the north and finer gravel and sand to the south (Woodworth, 1905). Kettle holes are common, with faulted bedding near the kettles, and unfaulted bedding dominating to the south. The lenticular gravel at the north grades southward into horizontally bedded, finegrained sediments (Woodworth, 1905). The eskers are overlain by cross bedded, gray and yellow sand (Cook, 1905). The esker complex grades southward into the Schodack kame terrace (Woodworth, 1905, Cook, 1930, LaFleur, 1965a, 1965b). Woodworth (1905) interpreted the Loudonville complex as being built by south-flowing, inglacial streams. Cook initially interpreted the complex as a crevasse filling (Cook 1930), but later re-interpreted it as being deposited in a blind, lake water-filled, ice-walled tunnel (Cook, 1946). He misinterpreted the rounded bluffs surrounding the complex as being molded by over-hanging ice walls (Cook, 1946), rather than as beach-cliffs cut by Lake Albany waves (Fairchild, 1918, LaFleur, 196lb, 1965b). Stop 16 shows a 16m fining-upward sequence of poorly-to well-sorted, ice-contact sand and gravel. The lower gravel contains boulders, silt, and cobbles in planar cross-beds which interfinger with cobble lenses. These lower beds are overlain by ripple-laminated sand that is overlain by lenticular, fining-upward, trough cross-bedded gravel and ripple-laminated sand. This sequence is overlain to the south by planar cross-bedded, ripple-laminated, deltaic fine silt and sand. The entire sequence is cut by gravity-faults that bound basins which filled with varved clay. The varved clay reaches an elevation of +400 ft. The +400 ft. varved clay and delta complex at Stop 16 was deposited in a lake that existed up-stream (north) from Lake Albany. The western edge of the esker complex was exposed in a building excavation at the corner of Osborne and Shaker Roads in 1976. This excavation contained a fining-upward sequence of trough cross-bedded gravel and sand. The gravelly sand beds were planed off, and were overlain by horizontally laminated, yellow brown sand. The entire sequence contained numerous gravity faults. The lower trough cross-bedded, gravelly sand was deposited in the esker. The upper, laminated sand was deposited in a Lake Albany beach. Stagnant ice lay in the area until after the lake dropped below the +330 ft. level, as indicated by the gravity faults. The area of this pit is probably the recharge of the Loudonville eskers' artesian groundwater system.

A4: THE STRUCTURAL FRAMEWORK OF THE SOUTHERN ADIRONDACKS
Hamilton, NY
The area referred to as the southern Adirondacks is shown in Figure 1. Within this region, the Precambrian is bounded approximately by the towns of Lowville and Little Falls on the west and Saratoga Springs and Glens Falls on the east.
Mapping in the southern Adirondacks was done first by Miller (1911, 1916, 1920, 1923), Cushing and Ruedemann (1914), Krieger (1937), and Cannon (1937); more recent investigations were undertaken by Bartholomew (1956), Thompson (1959), Nelson (1968), and Lettney (1969). At approximately the same time Walton (1961) began extensive field studies in the eastern portion of the area (Paradox Lake, etc.), de Waard (1962) began his studies in the west (Little Moose Mt. Syncline). Subsequently de Waard was joined by Romey (de Waard and Romey, 1969).
Separately and together, Walton and de Waard (1963) demonstrated that the Adirondacks are made up of polydeformational structures, the earliest of which consist of isoclinal, recumbent folds. Their elucidation of Adirondack geology set the tone for future workers in the area. In this regard one of their most important contributions to the regional picture was that the stratigraphy of the west-central Adirondacks is correlative with that of the eastern Adirondacks.
Beginning in 1967 McLelland (1969, 1972) initiated mapping in the southernmost Adirondacks just to the west of Sacandaga Reservoir. This work was extended subsequently north and east to connect with that of Walton and de Waard. Geraghty (1973) and Farrar (1976) undertook detailed mapping in the eastern half of the North Creek 15' quadrangle. This tied into investigations in the Brandt Lake region by Turner (1971). Recently, Geraghty (1978) completed a detailed study of the structure and petrology in the Blue Mt. Lake area. The foregoing investigations have increased our knowledge of the southern Adirondacks, and this field trip is designed to show as many examples of the region's structure, lithology, and petrology as time allows.
2011: This following trips are identical:

A4: THE STRUCTURAL FRAMEWORK OF THE SOUTHERN ADIRONDACKS

STOP 1. Peck Lake Fm.
This exposure along Rt. 29A just north of Peck Lake is the type locality of the sillimanite-garnet-biotite-quartz-feldspar gneisses (kinzigites) of the Peck Lake Fm. In addition, there are exposed excellent minor folds of several generations. Note that the F2 folds rotate an earlier foliation.
The white quartzo-feldspathic layers in the kinzigites consist of quartz, two feldspars, and garnet and are believed to be anatectic. Note that fish-hook terminations on some of these suggest that they have been transposed. It is also clear that these anatectites have been folded by F2 indicating a pre-F2 metamorphic event(s). In a similar fashion some garnets in the rock appear to be flattened while others do not. It is believed that the anatectites formed at the muscovite-quartz reaction and are essentially in situ melts. Further anatexis did not take place due to absence of vapor.

STOP 2. Irving Pond Fm., .5 mile north of Nick Stoner's Inn, Canada Lake .
The outer portion of the Irving Pond Fm. is exposed in low cuts along the east side of Rt. 29A just prior to the crest in the road heading north.
At the southern end of the cut typical, massive quartzites of the Irving Pond are seen. Proceeding north the quartzites become "dirtier" until they are essentially quartzose sillimanite-garnet-biotite-feldspar gneisses (kinzigites).
At the northern end of the cut, and approximately on the Irving Pond/Canada Lake Fm. contact there occurs an excellent set of F2 minor folds. Polished slabs and thin sections demonstrate that these fold an earlier foliation defined by biotite flakes and flattened quartz grains.
The Irving Pond Fm. is the uppermost unit in the stratigraphy of the southern Adirondacks. Its present thickness is close to 1000 meters, and it is exposed across strike for approximately 4000 meters. Throughout this section massive quartzites dominate.

STOP 3. Canada Lake Charnockite
These large roadcuts expose the type section of the Canada Lake charnockite. Lithologically the charnockite consists of 20-30% quartz, 40-50% mesoperthite, 20-30% oligoclase, and 5-10% mafics. The occurrence of orthopyroxene is sporadic. These exposures exhibit the olive-drab coloration that is typical of charnockites. Note the strong foliation in the rock.
Although no protolith is known with certainty for these rocks a metavolcanic history is suggested by their homogeneity and lateral continuity. Their bulk chemistry corresponds to dacites.

Canada Lake Store. Good exposures of Royal Mt. member of Green Lake Fill.

STOP 4. Rooster Hill megacrystic gneiss at the north end of Stoner Lake.
This distinctive unit is believed to be, in part, correlative with the Little Moose Mt. Fm. Here the unit consists of a monotonous series of unlayered to poorly layered gneisses characterized by large (1-4") megacrysts of perthite and microcline perthite. For the most part these megacrysts have been flattened in the plane of foliation as well as elongated in an E-W direction with concomitant developed of tails of grain-size reduced tails asymmetric to foliation. However, a few megacrysts are situated at high angles to the foliation. The groundmass consists of quartz, oligoclase, biotite, hornblende, garnet, and occasional orthopyroxene. An igneous rock analogue would be quartz-monzonite or granodiorite depending on concentration of K-feldspar.
The origin of the Rooster Hill is obscure. Its homogeneity over a thickness approaching 2.5 km suggests an igneous parentage. This conclusion gains support from the presence of localities where megacrysts appear to retain a random orientation, and from the occasional presence of what may be drawn out xenoliths of biotitic or amphibolitic gneisses. However, these features may be explained by other models. The contacts of the Rooster Hill are always conformable with enclosing units, and this suggests a metastratified (metavolcanic?) origin. However, the anorthosites of the region also show conformable contacts, and this may, in part, be due to tectonic flattening.
Recently Eckelmann (pers. comm.) has studied zircon population morphologies in the Rooster Hill and similar lithologies. His results strongly suggest an igneous plutonic origin. This would be consistent with the igneous origin assigned the Hermon granite of the northwest Adirondacks - a rock that is markedly similar to the Rooster Hill.

Low roadcut in kinzigites of Tomany Mt. Fm.

Long roadcuts of quartzo-feldspathic gneisses and metasediments
Long roadcuts of quartzo-feldspathic gneisses and metasediments of Lake Durant Fm. intruded by metagabbro and anorthositic metagabbro.

Roadcut of anorthositic metagabbro and metanorite.

Stop 5. Lake Durant and Sacandaga Fms.
Stop 5. Lake Durant and Sacandaga Fms. intruded by anorthositic gabbros and gabbroic anorthosites. These roadcuts are located on Rt. NY 10 just south of Shaker Place.
The northernmost roadcut consists of a variety of metasedimentary rocks. These lie directly above the Piseco anticline and are believed to be stratigraphically equivalent to the Sacandaga Formation. The outcrop displays at least two phases of folding and their related fabric elements. These are believed to be F2 and F3. A pre-F2 foliation is thought to be present. Both axial plane foliations are well developed here. Several examples of folded F2 closures are present and F2 foliations (parallel to layering) can be seen being folded about upright F3 axial planes.
Farther to the south, and overlooking a bend in the west branch of the Sacandaga River, there occurs a long roadcut consisting principally of pink and light green quartz-perthite gneiss belonging to the Lake Durant Fm. About half-way down this roadcut there occurs a large boudin of actinolitic and diopsidic gneiss. To the north of the boudin the quartzo-feldspathic gneisses are intruded pervasively by anorthositic gabbros, gabbroic anorthosites, and various other related igneous varieties. At the north end of the cut and prior to the metastratified sequences these intrusives can be seen folded by upright fold axes. They are crosscut by quartzo-feldspathic material.
Within this general region the Lake Durant Fm. and other quartzofeldspathic gneisses seem to have undergone substantial anatexis. This is suggested by the "nebular" aspect of the rocks. Good examples of this are seen in the manner in which green and pink portions of the quartzo-feldspathic gneisses mix. Note also the clearly cross-cutting relationships between quartzofeldspathic gneiss and mafic layers at the south end of the roadcut. Here it seems that mobilized Lake Durant is cross-cutting its own internal stratigraphy. Also note that the quantity of pegmatitic material is greater than usual. This increase in anatectic phenomena correlates closely with the appearance of extensive metagabbroic and metanorthositic rocks in this area. It is believed that these provided a substantial portion of the heat that resulted in partial fusion of the quartzo-feldspathic country rock.

Red-stained basal quartzo-feldspathic gneisses that have been faulted along NNE fractures.

Stop 6. Core rocks of the Piseco anticline.
Hinge line of Piseco anticline near domical culmination at Piseco Lake. The rocks here are typical basal quartzo-feldspathic gneisses such as occur in the Piseco anticline and in other large anticlinal structures, for example Snowy Mt. dome, Oregon dome.
The pink "granitic" gneisses of the Piseco anticline do not exhibit marked lithologic variation. Locally grain size is variable and in places megacrysts seem to have been grain size reduced and only a few small remnants of cores are seen. The open folds at this locality are minor folds of the F3 event. Their axes trend N70W and plunge 10-15° SE parallel to the Piseco anticline. Co-axial F2 isoclines are also present.
The most striking aspect of the gneisses in the Piseco anticline is their well-developed lineation. This is expressed by rodding and ribbon fabrics. These may consist of alternating ribbons of quartz, quartzo-feldspathic gneiss, and biotite-rich layers. In some instances the rods represent transposed layering on the highly attenuated limbs of early, isoclinal minor folds. Near the northeast end of the roadcut such minor folds are easily seen due to the presence of more massive layers in the rock. Slabbed and polished specimens from this and similar outcrops demonstrates that these early folds are exceedingly abundant in the Piseco anticline. Examination of these folds shows that the dominant foliation in the rock is axial planar to them.
The lineation in these outcrops is shown in Fig. 8a while slabbed sections are shown in Figs. 8b,c. Fig. 8b is cut perpendicular to foliation and both parallel to (left face) and perpendicular to (right face) lineation. As can be seen K-feldspar augen have been elongated in the direction of lineation. Together with elongated quartz aggregates, these grain size reduced minerals form the prominent mineral lineation that characterizes foliation surfaces (Fig. 8a). Note that the K-feldspar augen exhibit shapes closer to equant on the right hand face at perpendicular to lineation. This strongly suggests that the rock fabric is the result of rotational strain in the direction parallel to lineation, i.e., the lineation is an elongation, or stretching type. Fig. 9 shows a less deformed sample slabbed perpendicular to foliation and parallel to lineation. The development of tails on K-feldspar augen are clearly visible. These are the result of grain size reduction during ductile rotational strain. A sinistral (east over west) sense of motion is indicated. At more extreme conditions of strain the K-feldspar augen and quartz aggregates are drawn into ribbons as in the present outcrop. Long dimensions of 40-60 cm are common along with thicknesses of a millimeter, or less. Clearly strain has been extreme and elongations of 30-40 times are not unusual.
Ribbon gneiss origin by rotational strain is also suggested by the parallelism between lineation and F2, F3 fold axes. It is believed that these fold axes were drawn into parallelism with the lineation by ductile, rotational strain directed from east to west. The most satisfactory mechanism for this configuration is the stacking of thrust sheets and thrust nappes during plate collision. Thrusts have been recognized to the east of Lake George (Fig. 4) and others probably exist although the intense, ductile nature of the deformation has resulted in extremely subtle truncations that are difficult to recognize. Sheath folds (Fig. 10) with tube axes parallel to lineation are consistent with this model. Presumably crustal thickening during the Grenville Orogeny was caused by the stacking of these thrusts.

Stop 7. Blue Mt. Lake Fm. exposed in roadcuts on both sides of highway.
The Blue Mt. Lake Fm. is exposed in roadcuts on both sides of the highway. These exposures show typical examples of the extreme ductility of the carbonate-rich units. The south wall of the roadcut is particularly striking, for here relatively brittle layers of garnetiferous amphibolite have been intensely boudinaged and broken. The marbles, on the other hand, have yielded plastically and flowed with ease during the deformation. As a result the marble-amphibolite relationships are similar to those that would be expected between magma and country rock. Numerous rotated, angular blocks of amphibolite are scattered throughout the marble in the fashion of xenolith, in igneous intrusions. At the eastern end of the outcrop tight isoclinal folds of amphibolite and metapelitic gneisses have been broken apart and rotated. The isolated fold noses that rema in "floating" in the marble have been aptly termed "tectonic fish." The early, isoclinal folds rotate on earlier fo1iation.
Near the west end of the outcrop a deformed layer of charnockite is well exposed. In other places the charnockite-marble interlayering occurs on the scale of one to two inches.
Exposed at several places in the roadcut are cross-cutting veins of tourmaline and quartz displaying a symplectic type of intergrowth. Other veins include hornblende and sphene bearing pegmatites.
Commonly included in the Blue Mt. lake Fm., but not exposed here, are quartzites, kinzigites; sillimanite rich, garnetiferous quartz-microcline gneisses; and fine grained garnetiferous leucogneisses identical to those characterizing the Sacandaga Fm. These lithologies may be seen in roadcuts .5 mile to the south.
Almost certainly these marbles are of inorganic origin. No calcium carbonate secreting organisms appear to have existed during the time in which these carbonates were deposited (> 1 b.y. ago). Presumably the graphite represents remains of stromatolite-like binding algae that operated in shallow water, intertidal zones. If so, the other roadcut lithologies formed in this environment as well. This seems reasonable enough for the clearly metasedimentary units such as the quartzites and kinzigites. The shallow water environment is much more interesting when applied to the charnockitic and amphibolite layers. The fine scale layering, and ubiquitous conformity of these, strongly suggests that they do not have an intrusive origin. Perhaps they represent the metamorphosed products of volcanic material in a shelf like environment. Such intercalation is now occurring in many island arc areas where shallow water sediments cover, and in turn are covered by, ash and lava. Alternatively they may represent metasediments. A large lumber of minerals are developed within these outcrops. Both calcite and minor dolomite are present in the carbonate horizons. These are accompanied by green diopside and serpentinized forsterite as well as by tourmaline, graphite, and various sulfides. In calcsilicate horizons phlogopite, diopside (white), and tremolite occur. Wollastonite is locally present. The presence of tremolite and wollastonite is believed to be a function of the relative concentration of CO2 and H2O in the vapor phase Valley et al., 1983).

Extensive roadcuts in lower part of Blue Mt. Lake Fm.
Quartzites, kinzigites, and leucogneisses dominate. Minor marble and calcsilicate rock is present.

Large roadcuts in lower Lake Durant Fm.
Pink, well-layered quartzo-feldspathic gneisses with subordinate amphibolite and calcsilicate rock.

Stop 8. Intermediate Adirondack anorthositic gneiss
On the west side of the road small roadcut exposes an excellent example of Adirondack anorthositic gneiss intermediate in character between the so-called Marcy type (coarse) and the Whiteface type (fine grained). About 50% of the rock consists of fine grained crystals of andesine plagioclase. Some of these crystals appear to have measured from 6-8" prior to grain size reduction. Excellent moonstone sheen can be seen in most crystals. In places ophitic to subophitic texture has been preserved with the mafic phase being represented by orthopyroxene.
In addition to the anorthosite there exists a clearly crosscutting set of late iron-rich orthopyroxene rich dikes containing xenoliths of coarse grained anorthosite. The latter may represent a late mafic differentiate related to cotectic liquids responsible for the ophitic intracrystalline rest magma. This would be consistent with the iron enrichment trend characteristic of Adirondack igneous differentiation.
Near road level there can be found several inclusions of calcsilicate within the anorthositic rocks. These are believed to have been derived from the Cedar River Fm. and are consistent with a non-basement status for the anorthosite.
The upper, weathered surface of the outcrop affords the best vantage point for studying the textures and mineralogy of the anorthositic rocks. In several places there can be seen excellent examples of garnet coronas of the type that are common throughout Adirondack anorthosites. These coronas are characterized by garnet rims developed around iron-titanium oxides and pyroxenes. Recently McLelland and Whitney (1977) have succeeded in describing the development of these coronas according to the following generalized reaction:
Orthopyroxene + Plagioclase + Fe-bearing oxide + quartz = garnet + clinopyroxene.
This reaction is similar to one proposed by de Waard (1965) but includes Fe-oxide and quartz as necessary reactant phases. The products are typomorphic of the garnet-clinopyroxene subfacies of the granulite facies (de Waard 1965). The application of various geothermometers to the phases present suggests that the P,T conditions of metamorphism were approximately 8 Kb and 700 ± 50°C respectively.

Cedar River Fm. Minor marble, amphibolite, and calcsilicate rock.
Predominantly very light colored sillimanite-garnet-quartz-K-feldspar leucogneisses.

Leucogneisses of the Blue Mt. Lake Fm.
To the west of the intersection are roadcuts in leucogneisses of the Blue Mt. Lake Fm. A large NNE normal fault passes through here and fault breccias may be found in the roadcut and the woods beyond.

Entering Little Moose Mt. Fm.
Entering Little Moose Mt. Fm. on northern limb of the Glens Falls syncline. Note that dips of foliation are to the south.

Downdropped block of lower Paleozoic sediments.
Entering town of Wells which is situated on a downdropped block of lower Paleozoic sediments. The minimum displacement along the NNE border faults has been determined to be at least 1000 meters.

Silver Bells ski area to the east.
The slopes of the ski hill are underlain by coarse anorthositic gabbro intrusive into the Blue Mt. Lake Fm.

Lake Durant Fm
On the north side of NY Rt. 30 are quartzo-feldspathic gneisses and calcsilicate rocks of the Lake Durant Fm. An F1 recumbent fold trends subparallel to the outcrop and along its hinge line dips become vertical.

Gabbro and anorthositic gabbro.

Stop 9. Pumpkin Hollow.
Large roadcuts on the east side of Rt. 30 expose excellent examples of the Sacandaga Fm. At the northern end of the outcrop typical two pyroxene-plagioclase granulites can be seen. The central part of the outcrop contains good light colored sillimanite-garnet-microcline-quartz gneisses (leucogneisses). Although the weathered surface of these rocks are often dark due to staining, fresh samples display the typical light color of the Sacandaga Fm. The characteristic excellent layering of the Sacandaga Fm. is clearly developed. Note the strong flattening parallel to layering and the lineation developed on many foliation surfaces. These gneisses are similar to so-called straight gneisses found in proximity to ductile shear zones. The Sacandaga Fm. may represent mylonitic rocks of this type and its layering may, in fact, be tectonic.
Towards the southern end of the outcrop calc-silicates and marbles make their entrance into the section. At one fresh surface a thin layer of diopsidic marble is exposed. NO HAMMERING PLEASE. Many "punky" weathering layers in the outcrop contain calc-silicates and carbonates.
At the far southern end of the roadcut there exists an exposure of the contact between the quartzo-feldspathic gneisses of the Piseco anticline and the overlying Sacandaga Fm. The hills to the south are composed of homogeneous quartzofeldspathic gneisses coring the Piseco anticline (note how ruggedly this massive unit weathers). The Sacandaga Fm. here has a northerly dip off the northern flank of the Piseco anticline and begins its descent into the southern limb of the Glens Falls syncline.
No angular discordance or other indications of unconformity can be discerned at the base of the Sacandaga Fm. However, this does not preclude the prior existence of an angular discordance which may have been swept into pseudo-conformity by tectonism.
Along most of the roadcut there can be found excellent examples of faults and associated pegmatite veins. Note that the drag on several of the faults gives conflicting senses of displacement. The cause of this is not known to the author. Also note the drag folds which indicate tectonic transport towards the hinge line of the Piseco anticline.

Core of the Piseco anticline.
All exposures are within the basal quartzo-feldspathic gneisses at the core of the Piseco anticline.

Re-enter the Sacandaga Fm. Dips are now southerly.

Southerly dipping quartzo-feldspathic gneisses of Lake Durant Fm.
In long roadcuts of southerly dipping quartzo-feldspathic gneisses of Lake Durant Fm.

A5: MICROSTRUCTURE OF A VERMONT SLATE, AN ADIRONDACK GNEISS, AND SOME LABORATORY SPECIMENS
W. D. Means
State University of New York at Albany
M. B. Bayly
The aim of this trip is to examine the microstructure of some naturally and experimentally deformed materials and to discuss the relationships between the observed structures and the deformations they represent. The microstructures at each stop will be described using hand-out photomicrographs. The trip is therefore not very suitable for future use by independent field parties. These notes will accordingly be brief.

A5: MICROSTRUCTURE OF A VERMONT SLATE, AN ADIRONDACK GNEISS, AND SOME LABORATORY SPECIMENS

STOP 2. Quartzo-feldspathic gneiss
Exposure is mainly west side of new Route 4. Two smallscale features of interest occur here. The first is a quartz ribbon lineation trending east in the plane of the main southeast-dipping foliation. This is a common type of lineation in Adirondack gneisses, of obscure kinematic significance. The nature of this lineation will be discussed -- is it transposed quartz layering? stretched quartz aggregates or grains? synkinematic secretion ? or .... ?
The second microstructure of interest consists of partial feldspar rims, in preferred orientation, around feldspar grains. The hypothesis that these are in-fillings of potential voids between rigid grains in relative motion will be discussed.

STOP 3. Cedar Mountain Slate Quarry.
The quarry displays many structural features of interest, including variously shaped green spots and a large recumbent synform. The synform closes to the east (hinge-line subhorizontal, trending north); a folded surface is exposed on the west wall of the quarry and fold profiles are exposed in the north wall. The main cleavage that provides the slate is subhorizontal, axial-planar to this fold. On this trip, attention will be focussed on the crenulation cleavages which overprint the main slaty cleavage.
The crenulation cleavage is mostly an antithetic kink-like variety; it may be seen in places in two conjugate orientations consistent with shortening parallel to the (shallow) dip direction of the slaty cleavage. Puzzling features which will be illustrated and discussed are the less frequent occurrence of synthetic crenulation cleavage (perhaps suggesting extension in the dip direction of the slaty cleavage), and some dark layers enriched in "insoluble" material. In a few places these layers coincide with crenulation cleavage planes, but in many places the crenulations and the dark layers seem to be independent of each other --- not parallel and not genetically related although close together in the rock.

A6: CLEAVAGE IN THE COSSAYUNA AREA, AS SEEN AT THE OUTCROP
Lucian B. Platt
Bryn Mawr College
This trip crosses the Taconic allochthonous sheets in Washington County, N.Y., eastward on Saturday and westward on Sunday. The purpose is to look at various structures visible at outcrop and with a hand lens and to consider how much of the deformation can be attributed to dissolution. I believe that much rock has moved through solution, but many features seen at outcrop are not easily interpreted. At the west edge of the klippe rocks, the underlying carbonates are remarkably undeformed, and the Taconic Sequence, though folded and cleaved, does not show obviously massive rock loss. Eastward the situation becomes more complicated, and at the easternmost stop, extension fibers have formed in fanning "cleavage." I hope those taking the trip will share their observations and thoughts at the outcrop so that we all learn.

STOP 1. Bald Mountain, near Middle Falls, N.Y.
Re-enter the bus 1 hour after getting out.
Enter the quarry on the west side and walk around the southwest side of the hill along the old road. The quarry existed to produce lime, and some evidence of kilns remain. The geologic relations at Bald Mountain have been examined by scores of geologists for over a century. Published mapping by Ruedemann (Cushing and Ruedemann, 1914) shows Lower Ordovician limestone overlain by a thrust plate of Lower Cambrian shale. In fact, a screen of Middle Ordovician shale intervenes between, and the best explanation of the geology in this vicinity is that the carbonate floats as a tectonic fish in the Ordovician shale which is overlain by the thrust plate of Taconic rocks. Our interest in the locality is that we can see shale with pebbles of carbonate, and we can see some dissolution features adjacent to some of the carbonate. One point to note is how LITTLE deformation there is in the Ordovician carbonate, even in small pieces, in contrast to the cleaved shale.

STOP 2. One mile southeast of Argyle, NW quadrant of intersection.
Re-enter the bus after no more than an hour.
Some small folds in these Lower Cambrian carbonate, silt, and shale beds can be seen in the southwest part of the corner field. The chevron folds do not show much cleavage, but other parts of the pasture do. Dale (1899) found trilobites in both the pebbles and the matrix, but the conglomeratic look to the carbonate beds is probably due to insoluble residue concentrated along dissolution surfaces. The main point of this stop is to examine the styles of deformation in this more or less carbonate-rich part of the Taconic Sequence.

STOP 3. 1000' west of the south end of Cossayuna Lake.
Re-enter the bus in one hour.
At the road cut it is easy to see conglomerate of carbonate pebbles in shale and some beds of limestone in shale. Walk up to the outcrops of this rock on the slope north of the road cut. In several places the glacially scraped rock shows solution features in the carbonate. Seeing this requires getting down on hands and knees and using a hand lens in many cases; hence if it is raining, we will abandon this stop. One aspect of the solution of these rocks is that many solution features do not continue very far in the rock; they are approximately parallel to tight fold axes in the area. How much change in thickness of beds around tight folds, particularly in area of "similar" folds, is due to removal of rock? In nearly isoclinal folds, it is possible to show that dissolution could cause virtually all of it.

STOP 4. BM564
Re-enter bus after 30 minutes.
Folds in Lower Cambrian Mettawee and West Castleton Formations. This small outcrop is rich in deformation features. Chevron folds and kinks. Microboudins. "Slip" both ways on vertical cleavage. It is not clear to me how slip both ways could occur on parallel cleavage surfaces; hence I conclude that during folding a substantial part of the rock went into solution, and the plane along which material was removed only appears to be a line of slip. Years ago, Donath (1961) showed that slip occurs along surfaces of mechanical anisotropy; here we can infer that the cleavage we see was not a place of particular anisotropy before or during the early stages of its formation. Flattening by selective dissolution seems a better way to me. But where does the material go? What is the reservoir rock for this source rock?

STOP 5. Intersection of NYRoute 313 and County 61
Re-enter bus after about an hour and a half.
Quite a variety of wonderful things are visible at this roadcut. I suggest that you walk east along the outcrop before you get down to the details. The paucity of veins at previous outcrops is in sharp contrast to this spot. I doubt it is merely a matter of metamorphic grade, though this rock is obviously more metamorphosed than the first stops. These rocks are folded and veined (calcite before quartz?) but the cleavage is not particularly impressive. Nevertheless, small crenulations show concentrations of micaceous minerals along limbs quite like the drawings of Gray (1979, Fig.3), and I infer, as he does, that solution of quartz is a major factor in the wrinkling. A thin section of sandstone from this outcrop shows extensively twinned calcite vein material, some sutured sand grain boundaries, and very little but nevertheless some dark submicroscopic material in strings along some grain boundaries and in sutured grain contacts. In one vein it appears that the calcite twin lamellae are bent. In the thin section, only two sand grains other than quartz were found, so this particular section was not ideal rock to see mica beards, etc., as shown by Means (1975, Fig. 1 ).

STOP 6. Across from 1852 covered bridge over Battenkill in Vermont
Re-enter bus after 1 hour.
These carbonates are so-to-speak out from under the east side of the Taconic rocks we have been looking at between here and Bald Mountain (stop 1). As we have moved east and southeast across the Taconic Sequence, the metamorphism has increased, as was clear at the last stop. How does this affect the carbonates? Things to look at here include the following:
a. Crinoid stems in coarse beds. Although the crinoid is dead, the ossicle is in good condition.
b. Some calcite layers look schistose. Are these beds?
c. The difference in ductility between different layers is apparent.
d. Where are the stylolites in these strongly deformed rocks? Or are there just no insoluble residues?
e. Near the west end of the outcrop folded layers have fanning "cleavage" but the feature that is fanning has calcite fibers.
f. Some curved veins have fibers. Did the fibers survive folding, or did the fibers form after the folding of the veins, or did the veins from with their present curvature? This would seem to imply that the fibers are related to something different from compressional dissolution cleavage fanning the fold .

A7: THRUST SHEETS OF THE CENTRAL TACONIC REGION
Donald B. Potter
Hamilton College
This field trip is based on mapping in the Berlin, Hancock, and Williamstown Quadrangles during the summers of 1976, 77, and 78. This work was done for the U.S.G.S. and in conjunction with Nicholas M. Ratcliffe in preparation for the new geologic map of Massachusetts. The field trip concentrates on key exposures in the valleys of the Hoosic and Little Hoosic Rivers. In addition to the recent field mapping, the author has made some important reinterpretations of faults mapped earlier (Potter, 1972) in the Hoosick Falls area. Three major thrust sheets and a group of ·minor thrust slices are recognized in the central Taconic region. Their relative age of emplacement (oldest at bottom), correlation with previously named thrust sheets, and probable times of deformation are as follows:
Former Designations
(Potter 1972)
Present Designation
Stage of Deformation
| | F3
Not recognized as separate sheet. | IV. Berlin Mountain Thrust Sheet |
| | F2
Rensselaer Plateau Thrust Sheet | III. Rensselaer Plateau Thrust Sheet |
Not Named | II. Butternut Hill thrust slices |
| | F1
North Petersburg Thrust Sheet | Giddings Brook Thrust Sheet |
I. The Giddings Brook thrust sheet, a name from the northern Taconics and worthy of perpetuating in the central Taconic region, consists of very distinctive stratigraphic units (Figure 3.) several of which are fossiliferous. The dominant thrust sheet in the Taconic allochthon, it was emplaced in Mid-Ordovician time as a gravity slide. Beneath it in the central Taconic region is Mid-Ordovician Walloomsac slate with its Whipstock Breccia member, a wildflysch type of block and shale unit. The Giddings Brook thrust fault is recumbently folded, and the internal structure of the sheet itself is commonly that of a major recumbent anticline opening east with youngest formations at the base of the sheet.
II. The Butternut Hill thrust slices are small lenticular masses consisting of limestones and dolostones of the Stockbridge Formation with infaulted lenses of Rensselaer Graywacke. Near Berlin Village one of these slices truncates the trace of the Giddings Brook thrust fault and is, itself, truncated by the trace of the Rensselaer Plateau thrust fault. The Butternut Hill slices are envisioned as hard dry slices of rock dragged along the base of the advancing Rensselaer Plateau thrust sheet.
III. The Rensselaer Plateau thrust sheet consists dominantly of Rensselaer Graywacke with interbeds of maroon and green-gray slate. Near its base the Rensselaer sheet contains metavolcanic rocks. The position of the Rensselaer Plateau sheet structurally above the Giddings Brook is clearly indicated by numerous excellent exposures many of which have limestone or dolostone slices (Stockbridge Formation) at the thrust contact. This relationship is seen at Stop 2.
IV. Berlin Mountain thrust sheet. This name is given for the greenish and purple chloritoid-bearing slates and phyllites with few distinctive marker beds that make up the bulk of the Taconic Range. Berlin Mountain is a major crest in this range. That this is a separate thrust sheet is suggested by the following evidence: north of the Hoosic River (Stop 1) the chloritoid phyllites in question are separated from distinctive formations of the Giddings Brook thrust sheet by slices and slivers of Stockbridge carbonate rocks. The Giddings Brook sheet is isoclinally folded (F2) with the Rensselaer Plateau sheet and both lie beneath the Berlin Mountain thrust fault. Also, the position of the Rensselaer Graywacke in the Taconic Range (Figure 2.) casts doubt on an earlier working hypothesis in this region which states that the Rensselaer Graywacke was a basal stratigraphic unit in the thrust sheet that formed the range. The graywacke is seen to be limited to the north and south ends of the range and does not occur along the east or west edges nor in the center. Had that Rensselaer Graywacke been present as a stratigraphic unit at the base of the chloritoid phyllites it seems highly likely that it would now be found infolded with them. An alternate hypothesis is proposed: the Rensselaer Graywacke in the Taconic Range belongs to the Rensselaer Plateau thrust sheet; over the top of this was emplaced sheet IV, Berlin Mountain thrust sheet. Both sheets were subsequently cupped into a broad F3 synform whose axis trends northwest - southeast. Subsequent erosion has exposed the.· older, Rensselaer Plateau thrust sheet, albeit patchily, at the north and south noses of the synform. Elsewhere the Rensselaer sheet is covered by the Berlin Mountain (IV) thrust sheet.
At least three stages of deformation are recorded. Initial large and small scale recumbent folding (F1) occurred during the emplacement of the Giddings Brook sheet;· the axial plane cleavage (S1) that formed at this time has been subsequently rotated to a moderately steep southeast dip and has generally been overwhelmed by the development of a pronounced slip cleavage (S2). This slip cleavage is co-planar with the axial planes of F2 folds, isoclinal to asymmetrical with axial planes dipping east or southeast. F2 -folds are seen in the outcrop pattern at Stop 3; and a large south-plunging isoclinal anticline involving the Giddings Brook and Rensselaer Plateau thrust sheets is interpreted to be an F2 fold at Stop 1. F3 folds have northwest-trending axes. At Stop 3 they bring to the present surface the south-plunging Giddings Brook thrust fault and account for the northwest-southeast outcrop pattern superposed on a large F1 recumbent fold there; also, F3 folding accounts for a major fishhook pattern on the east side of the Taconic Range. The doubly plunging synform of the Berlin Mountain and Rensselaer Plateau thrust sheets in the Taconic Range probably is an F3 fold, and the Hoosick Falls embayment (west of Bennington, Figure 1.) is probably produced by erosion of an F3 anticlinal warp.

A7: THRUST SHEETS OF THE CENTRAL TACONIC REGION

The aim of this traverse is to demonstrate the anticlinally folded Giddings Brook (I) thrust sheet with Stockbridge Formation beneath the thrust fault to the west, and chloritoid schists of the Berlin Mountain (IV) thrust sheet above the Giddings Brook to the east. The latter contact is marked by long slivers of limestones and dolostones (Stockbridge Formation). A large F2 anticline is indicated by the exposure, half-way through this traverse, of autochthonous formations - Whipstock Breccia and Austin Glen Graywacke members of the Walloomsac - beneath the folded Giddings Brook thrust fault.
In the fields above the parking location are limestones and dolostones of the Stockbridge Formation (probably units F and G). One layer in this sequence yields early Ordovician brachiopods. Other layers in these fields carry Post-Canadian brachiopods, ostracods, trilobites, bryozoa and are mapped as Walloomsac limestone (Owl).
Crossing the Giddings Brook Thrust Fault at the saddle, we encounter various formations of the G. B. thrust sheet: medium-light gray, some dolomitic slates (Poultney); dark gray and black slates (Hatch Hill) enclosing the Eagle Bridge Quartzite; green-gray slate (Mettawee) and Zion Hill Quartzite. At the 1027 crest we cross the Giddings Brook thrust and see autochthonous rocks of the Walloomsac Formation. The dominant lithology here is the Whipstock Breccia, a dark gray slaty rock crowded with rusty and white-weathering chips of siltstone and sandstone. The Whipstock encloses lenses of sheared limestone and dolostone (Stockbridge Fm.) and lenses and beds of Austin Glen Graywacke. The Whipstock is interpreted to be a submarine slide breccia facies of the Walloomsac, deposited in front of the advancing Giddings Brook thrust sheet and containing blocks and lenses of the Taconic Sequence as well as of the Stockbridge Formation and the co-deposited Austin Glen Graywacke.
From crest 1027 to crest 1294 we cross the Giddings Brook thrust again and then traverse across variably foliated olive-weathering siltstone (Bomoseen), and dark gray slates containing limestone lenses (West Castleton); east of crest 1294 we encounter a large sliver (2000 feet long and up to 200 hundred feet wide) of sheared limestones and dolostones (Stockbridge Formation) which marks the sole of the highest thrust sheet (Berlin Mountain (IV) Thrust Sheet). The dominant lithology of the Berlin Mountain sheet is green and purple chloritoid schist, with coarsest chloritoid commonly near the thrust fault.
Return to parking area by traversing along the trace of the Berlin Mountain thrust sheet marked by slivers of carbonate rocks.

Folded Stockbridge and Walloomsac Limestone
Large exposures of recumbently folded Stockbridge (unit G) and Walloomsac limestone on right (west) side of highway.

Cross trace of (Giddings Brook) thrust fault
Cross trace of (Giddings Brook) thrust fault, and proceed south on Taconic Sequence formations near base of G. B. thrust sheet.

Bold cliffs on Taconic Mountains to east
Barn on east side highway, house on west. Bold cliffs on Taconic Mountains to east are Rensselaer Graywacke near base of Rensselaer Plateau thrust sheet.

Bomoseen Graywacke on right side of highway.

Massive exposures of Mettawee slate on west side of highway.
These slates are at the core of the Giddings Brook nappe.

STOP 2. Exposure of the Rensselaer Plateau thrust fault
Exposure of the Rensselaer Plateau thrust fault north of Prosser Hollow. Below the thrust fault is an apparently normal sequence of Bomoseen, Mettawee, and Hatch Hill (with Eagle Bridge Quartzite) - all part of the Giddings Brook thrust sheet. The Rensselaer Plateau (III) thrust fault is marked by slivers of limestone and dolostone (Stockbridge Formation) that have been tectonically dragged to their present positions. Immediately above the Rensselaer Plateau thrust is the Rensselaer Graywacke, perhaps several hundreds of feet thick and intensely sheared. The Graywacke is faulted against chloritoid schist 0.3 miles east of this stop, at the trace of the Berlin Mountain thrust fault.
The following details of the Rensselaer Plateau fault zone are noted. First, the Rensselaer Graywacke above the thrust is mylonitic through a zone approximately 150 feet thick (measured perpendicular to foliation), and the mylonitic foliation is concordant with normal foliation above and below the thrust zone. Second, the thrust plane truncates the mylonitic foliation. Third, a well-developed foliation parallel to the thrust plane occurs in the uppermost 2-3 feet of the limestone. Numerous other structural features may be observed. Widely spaced fractures, parallel to the thrust plane, also truncate the foliation and show a similar sense of movement to that on the thrust. Several warps in the thrust plane apparently represent areas where (later) movement on the thrust has locally followed the foliation instead of cutting across it. Near the upper (western) end of the outcrop, a sliver of mylonitic graywacke about 5' X 5' is completely enclosed within the limestone. West of this, the thrust plane steepens and follows the trend of the foliation in the graywacke for an indefinite distance.
The earliest structural event well-represented at this stop is the formation of the pervasive axial plane foliation, S2, and the accompanying regional metamorphism. Emplacement of the graywacke along the Rensselaer Plateau Thrust may have occurred prior to the formation of S2. Evidence for this is the occurrence in several places along the thrust of tectonic slivers of autochthonous carbonates around which S2 has been refracted.
The mylonites either were pre S2 and rotated into their present orientation during the formation of S2, or else formed at the same time as the foliation. The latter explanation is preferred.
Following S2, minor movement occurred between the Graywacke and the slates beneath. This movement caused the presently observed thrust plane, the thin zone of well-developed foliation in the upper few feet of the limestone, and the low angle fractures in the rocks immediately above and below the thrust. Perhaps we are seeing the results of a stick/slide phenomena of thrust faulting and not discrete periods of foliation formation followed by minor movement.

Bomoseen and Mattawee members on west side of Route 22.
From here to Petersburg we are in the lower part of the Giddings Brook thrust sheet which has a recumbent anticline structure. Formations exposed in the channel of the Little Hoosic, or near road level, are typically younger formations of the Taconic Sequence on the inverted limb of the recumbent anticline; higher on the east and west slopes of the Little Hoosick Valley are older formations of the nappe, and above these is the Rensselaer Plateau thrust sheet.

Mettawee on right.

STOP 3. Jones Hollow-Satterlee Hollow refolded recumbent
The southward plunge of the Giddings Brook thrust is interupted here by F3 cross-folds bringing the sole of the Giddings Brook thrust and underlying Walloomsac to the surface. Walloomsac floors the valley of the Little Hoosic River southward from this point.
The JH-SH recumbent covers an area about two miles long and one mile wide. Its outcrop pattern and small scale structures indicate three stages of deformation. The core of the large recumbent fold is marked by Walloomsac slate, and by Stockbridge units F and G.; its upper limb consists of slates of the Mettawee and Poultney formations; its lower limb consists of Mettawee slates, Mudd Pond Quartzite, Hatch Hill Formation. The stages of deformation can best be understood by referring to the map pattern and section. On the map the upper limb has the pattern of a 2 mile-long ram charging northeast. The ram's back gives the northeast trace of the axis of the recumbent fold (F1); the axial plane cleavage (S1) associated with this recumbent fold has been rotated from its presumed low angle of dip and it is not as easily seen as is S2. The second stage of deformation resulted in a northeast - striking slip cleavage (S2) which dips 35-50 degrees southeast and is co-planar with axial planes of F2 folds. The ram's head and chest are produced by F2 folds and the northeast - trending fault that truncates the ram's nose is parallel to S2. Northwest - trending F3 folds form the pointed foreleg and the ram's tail.
We will visit outcrops of Walloomsac and Stockbridge units F and G in the core of the recumbent fold, and the Poultney and Mettawee formations on the upper limb. Of particular interest are the long splinters of Poultney slate formed by S1-S2 intersection.

Jones Hollow-Satterlee Hollow recumbent
Jones Hollow-Satterlee Hollow recumbent forms prominent hills at 10-11:00 o'clock.

Outcrops on both sides of road of green Mettawee slate

Mettawee slate on right in woods.
Outcrops above this on east slope on Sugarloaf Hill show pronounced development of S1 and S2 cleavages.

Mettawee slate on right

Large outcrops of Stockbridge limestones and dolostones
On the right (west) side of road, large outcrops of Stockbridge limestones and dolostones (units D and E) which are part of the Butternut Hill thrust slice.

Walloomsac slate on right.

Walloomsac slate on left.

Walloomsac slate on both sides of road

STOP 4. Butternut Hill.
We will traverse 3/4 mile east over the top of Butternut Hill to East Road where we will be picked up by busses. The purpose of this stop is to see one of the smaller thrust slices in this part of the Taconic allochthon: the Butternut Hill (II) thrust slice. The age of its emplacement relative to other thrust sheets cannot be demonstrated here for it is simply floating in Walloomsac. However, one-half mile south of the village of Berlin, an identical thrust slice cuts the trace of the Giddings Brook thrust fault and is, itself, truncated by the Rensselaer thrust fault, thus establishing the Butternut Hill slice as number II in a series of IV sheets or slices.
The Butternut Hill slices (they are not connected) consist of various members of the Stockbridge Formation with in-faulted Rensselaer Graywacke. This distinctive combination of autochthonous carbonate formations and massive allochthonous turbidite can be found as scores of slices ranging from 2 miles2 in area (Berlin Village locality) down to slices a few a few feet in length. The slices are generally tucked up under the Rensselaer Plateau thrust fault and may simply represent slabs of Stockbridge carbonate formations into which the Rensselaer Graywacke was kneaded as the Rensselaer thrust sheet advanced. Some features of the Butternut Hill slices still remain a puzzle: Why wasn't Walloomsac drawn up with the Stockbridge in these slices? Why do we see only one lithology of the Taconic Sequence (Rensselaer Graywacke) in these slices?
Our traverse will take us across Walloomsac which displays S1 and S2 cleavages; a thin mylonite zone; units G and F of the Stockbridge; Rensselaer Graywacke and associated green phyllite.

Gentle slopes on your left (east) underlain by Walloomsac and Stockbridge
Gentle slopes on your left (east) underlain by Walloomsac and Stockbridge formations; above these on the steep slopes is a thin wedge of the Rensselaer Plateau (III) thrust sheet and above that the Berlin Mountain (IV) thrust sheet.

Stockbridge (unit D) thin platy gray limestone on left.

STOP 5. Volcanic rocks and Rensselaer Graywacke
Volcanic rocks and Rensselaer Graywacke at the base of the Rensselaer Plateau Thrust sheet. Here, as at many localities along the east edge of the Rensselaer Plateau and to the southeast, tbe base of the Rensselaer Plateau thrust sheet is marked by a dark green hard metavolcanic unit rich in epidote and chlorite. At one locality within the graywacke terrain on the plateau a similar volcanic unit displays pillow structure. Elsewhere, as at the present locality, the metavolcanic rock appears banded to massive and is characteristically highly deformed. The parent rock was probably a mafic tuff or flow.
We will examine the outcrops of deformed metavolcanic rock and then traverse about l/4 mile north to see the overlying Rensselaer Graywacke.

A8: DETAILED STRATIGRAPHIC AND STRUCTURAL FEATURES OF THE GIDDINGS BROOK SLICE OF THE TACONIC ALLOCHTHON IN THE GRANVILLE AREA
Rowley, D.B., Kidd, W.S.F. and Delano, L.L.
State University of New York at Albany
Albany, New York 12222
SUMMARY
The trip will visit localities in the "Giddings Brook Slice" of the lower Taconic allochthon in the vicinity of Middle Granville, New York. Eight localities will be visited, at each the stratigraphy and structure of the lower Taconic allochthon will be described and investigated in detail. Stratigraphically, the stops will emphasize our recognition of a more detailed stratigraphy than previously defined, specifically, the presence of two Cambrian black-green lithologic boundaries, abundant sedimentologic evidence for deep water North American continental rise depositional environment and the need for a Taconic reference section with well defined stratigraphy and known stratigraphic contacts. Structurally, the trips will focus on the nature of the continental rise sediments at the time of emplacement on the continental shelf and the nature of the deformation associated with emplacement. Particular emphasis will be placed on evidence suggesting that the low Taconics were emplaced as coherent tectonic slices and not as soupy soft sediment slides as all previous tectonic interpretations have suggested. Instructions to Participants Participants must bring their own pack lunch. There will be no opportunity to obtain it during the trip. This trip involves 1 1/4 hours travel before the first stop but compensates for that by having little distance between stops in the field area. Good outcrops in the Taconics are rare -- PLEASE DO NOT HAMMER OR DEFACE OR OTHERWISE DESTROY OUTCROPS -- Please take samples only if you will be doing bona fide research with them.

A8: DETAILED STRATIGRAPHIC AND STRUCTURAL FEATURES OF THE GIDDINGS BROOK SLICE OF THE TACONIC ALLOCHTHON IN THE GRANVILLE AREA

Route 40 follows closely the western edge of the Taconic Allochthon
Lowlands to the west are mostly underlain by autochthonous and parautochthonous shales and lesser greywackes (Normanskill/Snake Hill). Road cuts on right of deformed (shelf) carbonates that are at the sole of the Taconic allochthon.

Sole of the Taconic allochthon.
Road cuts on right of deformed (shelf) carbonates that are at the sole of the Taconic allochthon.

Road runs within the Taconic allochthon for next 9 miles

Optional STOP (a) 1.5 to 2.5 miles west of the junction of 22 and 40
Road cuts show gently east-dipping autochthonous carbonates whose unfolded, undeformed structural condition contrasts markedly with that of rocks in the Taconic Allochthon only 2 miles to the east.

OPTIONAL STOP (b) 1.2 miles north of the junction
Go straight across 22 from Rte. 40 and follow dirt road to dirt parking area on right above Mettawee River. Go over stile and follow path down slope to river. Gently east-dipping (10- 15°) carbonates (autochthonous or parautochthonous) extend to north along west bank of river and also illustrate little deformed nature of platform rocks, in this case less than 1/2 mile from the western edge of the Allochthon. Dark shales on east bank have lenticular cleavage and may be part of melange terrane bordering Taconic Allochthon.

STOP 1. Roadcut and stream outcrop on NY Rte. 22 near Truthville
Walk east along Rte. 22 (N side) past road cut and angle left down to stream at east end of cut.
PLEASE DO NOT WANDER IN THE ROAD OR OBSTRUCT TRAFFIC - IT TRAVELS AT LETHAL SPEEDS HERE.
The lowest lithounits exposed in the area. The glacially polished outcrop by the stream and the roadcut expose typical lithology in atypically good outcrop.
This outcrop shows typical Bomoseen lithologies in atypically clean outcrop. The dominant rock type is a poorly and lenticularly-cleaved green silty wacke. Where a polished surface is seen, as in the stream outcrop, this lithology is in part internally finely laminated and bedded, although it is not possible to detect this in the road cut or weathered outcrops. A subordinate lithology, which is almost always present in outcrops of Bomoseen, consists of rather diffusely bounded thin (cm) beds of fine sandy green quartzite. These always contain narrow extension gashes perpendicular to bedding.
The etched polished surface of the stream outcrop shows the fine bedding and some cross-lamination in the wacke, disturbed in places by sediment loading/injection structures. Folds in this outcrop are probably due originally to soft sediment deformation and slumping, as is the disruption of the quartzites seen here and locally in the northern roadcut.
At the western end of both roadcuts, about 2 meters of thicker and well-defined planar-bedded green medium-grained quartzites from a contrasting member, which would be identified as "Zion Hill quartzite." It is not common in this area. The Bomoseen is structurally underlain and stratigraphically overlain at the western end of the outcrop by green silty micaceous slates of the Truthville Formation.
The gently to moderately east-dipping bedding and near-parallel slaty cleavage are characteristic of almost all outcrops in the Giddings Brook Slice, and imply the presence of very tight folds. A mesoscopic, tight antiformal fold with a gently south-plunging hinge is seen in the center of the northern cut. Although this example may owe its existence to disorientation of layering during soft-sediment deformation, its geometry and orientation are representative of the larger-scale folds. Bedding/cleavage orientations at the Truthville Slate-Bomoseen contact in the southern cut imply (correctly) that the succession is inverted in this outcrop. Many post-cleavage, slickensided faults with small offsets are seen.

STOP 2: Quarry adjacent to Holcombville Road
Mettawee Slate Formation and contacts.
The basal contact of the Mettawee Slate Formation is exposed on the east side of this quarry (the strata are inverted) next to the track leading to the water's edge (bear slightly left past the ruined shed). The stratigraphically lowest beds exposed consist of 1 to 5 cm nodular micritic limestones in dark grey slate, assigned to the top of the Browns Pond Formation, as is the single 30 cm bed of laminated calcarenite, which can be seen in the north wall of the quarry in a thicker development. The rest of the rocks exposed in the quarry, stratigraphically above this calcarenite are assigned to the Mettawee Slate Formation (sensu stricto- see stratigraphic discussion). Some diagenetically dissolved nodular micritic limestones occur in the basal few meters of green slate, together with a limestone breccia less than a meter thick which is only exposed along the base of the east wall of the quarry (water level usually prevents easy access to this bed). Several meters of purple slate with diffuse boundaries occur within green slate on the north wall of the quarry (we will not examine this; purple slate may be seen in loose pieces near the quarry). The rock then turns from green to shades of grey slate, exposed on the west wall.
Fissile, sooty, black, pyritiferous slate of the basal Hatch Hill Formation lie not more than 5 meters, stratigraphically above (structurally below) this porcellanous gray slate. At least two beds of coarse dolomitic arenite occur not more than 10m above the slate in the west wall of the quarry. These exposures which will not be visited on the formal field trip, may be found by walking south on Holcombville Road from the quarry entrance to the dirt track that runs around the south end of the quarry. Follow this track until it comes to an open space in front of a large slate heap. Outcrops are in the track and to the west in the bushes.

STOP 3: Browns Pond Formation and Mettawee Slate
Stop at or before the place where Browns Pond comes closest to the road. At this point a dirt track can be found leading east from Holcombville Road. Turn vehicles around, park at side of road, and fol low the trace for:
STOP 3A. Lower part of Browns Pond Formation in the type area.
10 m from road along track there is a small outcrop of buff-weathering green Mettawee Slate in the bed of the track. Track turns left and up slope. In bushes on right, thin bedded calcarenites and black slates outcrop that are much better exposed in Stop 3b (below). Track turns right; passing by cabin small outcrops also of dark calcareous slate and thin-bedded limestone are seen. Track passes small pond/swamp on left and turns right (to S). At bend in track is outcrop and loose pieces of distinctive grey-black wacke (Black Patch Grit lithology) containing large rounded quartz grains, and dark slate rip-up clasts. Track turns left (to E) and after 20 m a low ridge occurs. To left (N) of track, exposure of about 7 m thick homogenous pale-weathering coarse quartzite (Mudd Pond Quartzite lithology). Grey-black quartz wacke found at base of outcrop. Rejoin track, finding more wacke in outcrop west of the track just north of where it turns from NE to N-trending opposite a cabin down the slope. North of the cabin, below the track, another thick quartzite is exposed. Black slate can be found in poor exposures stratigraphically below this second quartzite which we will not visit. Beyond the slope is a swamp-filled narrow valley on both sides of which Truthville slate is exposed and beyond which Bomoseen Formation is encountered. Return to Holcombville Road.
Mudd Pond Quartzite lithology may occur in 2 large beds (here-rare), one (e. g., Stop 5), or, more commonly, is not present. These highly lenticular discontinuous quartzites probably occupy channels.
Black Patch Grit lithology is more often present than Mudd Pond, and is a better lithostratigraphic marker (see Stratigraphic discussion). Its extreme mixture of grain sizes, rip-up clasts and, locally, included pebbles and boulders, suggest a slump to debris flow origin.
STOP 3B. Upper part of Browns Pond Formation in the type area.
From dirt track, walk south along Holcombville Road to first roadcut on left (east) side of road on small rise. Thin-bedded, dolomitic, laminated and cross-laminated, dolomitic calcarenite and calcisiltite are interbedded with black calcareous slate. Cross-lamination demonstrates inversion of these beds. This lithologic assemblage, although prominent in this local area, is not common in the Browns Pond Formation.
Walk north on the road to the roadcut on the western side. This mostly consists of a distinctive limestone breccia with close-packed homogenous grey limestone clasts of irregular but compact shape, set in an orange weathering dolomite-rich matrix, containing some quartz grains, that occupies a small proportion of the whole rock. Probable crack-injection relationships between matrix and clasts can be seen in places. Contacts of this breccia with areas of dark fine-grained thin bedded limestone and calcareous slate are seen, with the bedding truncated and no convincing signs of faulting. At the north end of the outcrop a possible block of breccia 2 m across rests within bedded material. In other places the bedded material seems to be in large clasts within or perhaps forming a matrix to large blocks of the breccia. Thus there seems to be evidence of mutual breakup of breccia and bedded limestones; however, there is no evidence that the breccia itself was formed in situ. Instead we suggest that it was deposited as consolidated blocks.---Theokritoff (1964) reports fossils from this outcrop. This distinctive breccia is only seen, when it occurs, very close to the top of the Browns Pond Formation. A rather similar breccia, seen rarely in the overlying Mettawee Slate Fm. is in a much thinner bed and has a significantly larger proportion of matrix. Debris flow deposits with carbonate blocks and slaty matrix are more common than this type in the Browns Pond Formation and will be seen at Stop 5.
STOP 3C. Go through gate in fence on the western side of the road, north of the roadcut just examined. Walk west to shore of pond across outcrops of distinctively buff-weathering green slate of the Mettawee Slate Formation. These are stratigraphically above the carbonates of the Browns Pond Formation, just seen. At the pond shore, a ledge-like outcrop exposes sooty black pyritiferous slate and some beds of laminated calcarenite and calcisiltite. Inverted cross-lamination can be seen. At the north end of the ledge, a 10 cm bed of pebbly limestone breccia is seen containing a minor amount of dark phosphatic pebbles. This green-black slate change is the upper of the two black-green boundaries in the area and correlates with the one seen in other areas of the Taconics. The locally developed limestone and black slate assemblage can be mapped as West Castleton; however, it is perhaps more easily mapped as a basal member of the Hatch Hill Formation. The limestones in this outcrop, and in 3b are probably turbidites, mostly representing the D and E horizons.

STOP 4. Five units repeated across syncline
Hatch Hill, Poultney, Indian River, Mt. Merino and Pawlet Formations repeated across syncline-Tanner Hill Road.
This stop entails walking for 1.1 miles west along Tanner Hill Road. Start at roadcut on north side on slope of hill. Thin to thick (1 cm-3 m) bedded dolomitic sandstone and quartzite beds; distinctive orange deep weathering rottenstones, interbedded with fissile black pyritiferous slate. Thickest beds are internally massive, very close sandstones and contain rip-ups of finer dolomitic sandstone. Thinner beds are finer grained, parallel laminated, uncommonly cross-laminated and only some show grading. In this outcrop, one side of a channel (proving inversion of this section) can be seen at the base of the thickest bed. The dolomite in these sands (10-50%) was originally clastic although now recrystallized.
The thick beds are either grain flow deposits or traction deposits at the base of large turbidity flows; in either case they fill channels. The thinner laminated beds are more problematic; those showing grading are probably turbidites, but the laminated beds with sharp tops and bottoms are harder to interpret. They are probably too coarse to represent deposits on levees of submarine turbidite channels.
The top of the Hatch Hill Formation at this locality, proceeding up the hill, consists mostly of black slate with a few very rotten weathering sandstones. If limestones occurred in this black slate, as they do in places, they are traditionally (Theokritoff, 1964; Potter, 1972) placed as a basal member of the Poultney -- another instance where the lithostratigraphy might usefully be changed. However, the resulting confusion might be worse than the existing kind.
Just west of the small borrow pit on the north side of the road, the low outcrop shows a rapid gradation from black to green slate with thin subordinate dark slate laminae. This is the base of the Poultney Formation. Opposite the quarry entrance, thin (mm) silty quartzite laminar beds are seen; these are characteristic of the Poultney and may be seen in the low, more or less continuous outcrop on the north side of the road, in varying abundance, throughout this formation. Their universally silty grain size, fine parallel and lesser cross laminations, the absence of associated coarser quartz-rich sands and the abundant indications of burrowing in the associated slightly silty slates, particularly well shown near the top of this section), are suggestive evidence that these silty quartzites were deposited by deep contour currents and that they are contourites.
By a track leading off the road to the north a 1 m section of maroon slate is exposed and two more sections containing maroon slate, one 5 m thick, are exposed to the west, up the hill. This maroon horizon can be traced locally to the north but is not found elsewhere in the area and is regarded as rare. The color of the slate is somewhat different and moderately distinguishable from the purplish Mettawee slate below and the red Indian River slate above.
In the whole of the section thus far up to the Indian River Formation contact, bedding is sensibly parallel with cleavage, reflecting the tightness of the large-scale folds.
The Indian River Slate Formation follows across a 5 m thick zone of interlayered red and green slate. The sea (blue) green porcellanous slate of the interlayered zone contrasts with the olive-green and silty nature of the Poultney slate and sea-green slate of this type is always placed with the Indian River, since red slates within the Indian River can be seen elsewhere to alter to this type. A good illustration of this may be seen at the western contact (top) of the Indian River exposed on the west side of the road about 0.2 mile north of the contact with the Poultney Fm., where relic patches of red slate may be seen diffusing into the sea-green slate. Elsewhere the Indian River may in places be altered to this green slate across its entire thickness.
Rare silty quartzite laminae identical to those in the Poultney occur within the lower part of the Indian River. Pale buff-weathering laminae or layers, pale greyish-white on a fresh surface, are siliceous but well-cleaved and interpreted to have been silicic ash beds, now tuffs. These are slightly better developed in the second occurrence of Indian River, 0.5 mile along the road, but the thickest beds (10-15 cm) can only be seen in exposures not readily shown to large groups. The spotty appearance of many cleavage surfaces in the Indian River, as if coarse sand grains are scattered through it, is due to ellipsoidal, microcrystalline quartz aggregates, probably recrystallized radiolaria.
Bedding-cleavage obliquities reflecting mesoscopic folds are seen locally within this belt of Indian River Fm.
The source of this notably red clay is proposed (Bird & Dewey, 1970) to be terra rossa soils developed on the karst surface that cuts the sub-Black River and Trenton platform carbonates. The soils provided the clays transported out to the continental rise; the rocks do not seem to provide clues to their last agent of transport, which may have been contour currents.
From the north-south road segment along which Indian River is exposed, the road turns west. On the southwest side there is a small outcrop of greyish cherty slates transitional to the Mt. Merino Formation, whose lower member is seen in a cut on the northeast side of the road. Chalky-weathering dark cherts 1-5 cm thick are interbedded with dark grey and black slates and cherty slates. The upper member of the Mt. Merino Fm. is not seen here or elsewhere on this trip; it consists of a sooty black slate that is commonly graptolite-bearing (Zones 11 and 12 of Berry). The two members can be shown to be a facies of one another, with the variable being the abundance or lack of chert.
To the west of this outcrop, where the road turns back to the north, a small excavated outcrop to the west and southwest of the road exposes fine silty greywackes of the basal Pawlet Formation. A fine development of a spaced cleavage oblique to bedding and bedding-parallel parting produces a well developed pencil-slate.
North and west along the road, the major synclinal axis is crossed and then the stratigraphy is repeated in reverse order. At the top of a gentle hill, an outcrop of the cherts of the Mt. Merino Fm. is seen on the right, followed by red slates of the Indian River down the slope on the left. At the north end of this outcrop the contact with the Poultney Fm. is exposed. Intermittent outcrop of Poultney Fm. occurs as the road turns from N-S to about E-W. Just around this bend, a larger outcrop of Poultney on the left has been reported by Theokritoff (1964) to contain graptolites of Berry's Zone 6. The next outcrop on the left contains black slate and lesser dolomitic arenites of the upper Hatch Hill Formation; Theokritoff (1964) reports dendroid graptolites of Tremadocian age from this cut. More Hatch Hill Fm. outcrop occurs at and south of the intersection with Truthville Road.
All along this road, except locally near the core of the syncline, bedding and cleavage are sensibly parallel and dip 20-40° east. We emphasize that this requires the large-scale folds to be near isoclinal in geometry with axial surfaces dipping at the same attitude as the slaty cleavage.
End of Stop 4.

Poultney / Indian River contact
Contact of green Poultney Formation with red Indian River Formation. Road runs N-S

Mt. Merino cherts on right.
Road curves to left - outcrop of Mt. Merino cherts on right.

Mt. Merino cherts
Road curves to right - outcrop of Mt. Merino cherts on right at top of hill

Indian River red slates exposed on left.
Road runs N-S.

Poultney Formation outcrop on left reported fossiliferous.
Road turns to W.

Optional STOP (c). Old Indian River Slate Quarries
Pass dirt track to left which leads to old Indian River slate quarries (permission required). Follow track, taking left fork when choice encountered. After fork, park when track turns sharply S after tall ridge outcrop (of Mt. Merino cherts) in trees on right (south). Head NE from track; south end of quarry should be encountered after 30 metres. Tight F1 folds well-displayed in south wall of quarry are prominent because of pale-weathering siliceous tuff beds (meta-bentonites) up to 10 cm thick. DO NOT HAMMER, PLEASE.

STOP 5. Bomoseen To Pawlet
Mettawee River section by North Granville
STOP 5A: - Starting at waterfall where Mettawee River bends sharply north and smaller stream joins it from SE. Get to top of falls by going up the bank and around behind the small cliff, in the woods. Typical Bomoseen lithology of green silty wacke and cm thick diffusely bounded, green fine-grained quartzites seen beside falls and in cliff. An M-style fold of D1 generation may be seen at the base of the cliff. Where the cliff curves away from the river into the earth bank, the contact with the Truthville Slate Formation is exposed.
This consists of typical silty mica-spangled olive-green slate: very close to its contact with the Bomoseen, there is a 20 cm thick bed of clean medium-grained quartzite, of Mudd Pond type. Thicker occurrences of Mudd Pond Quartzite in this stratigraphic position exist in several places. A thin lenticular occurrence of green, planar bedded quartzite of "Zion Hill" type is seen in the top of the Bomoseen at the base of the cliff. A few thin (mm) laminae of silty quartzite are present here in the Truthville Slate Fm.
At the first rapids with a large erratic boulder in midstream, the first black-green boundary is exposed, the contact between the Truthville Slate Fm. and the Browns Pond Fm. The slate grades rapidly from green to dark grey and loses its silty nature and mica-flakes. Upward (stratigraphically) there is a debris flow with limestone, laminated micrite and dark slate clasts in a slaty matrix. Above this, at the small promontory, several 30 cm to 4 m thick beds of Mudd Pond-type quartzite occur within dark slate and minor black calcareous wacke. (Black Patch grit lithology). Large load casts can be seen on the base of the quartzite beds and evidence is seen for injection of black slate and wacke into the quartzite. A small fault cuts across the quartzites parallel to the stream.
Small quantities of black quartz wacke are found in black slate for a short distance above the quartzites, as at Stop 3a. Here it is not clear if they are pieces in a debris flow or in lenticular beds. In either case their shapes have been much changed by flattening in the slaty cleavage. Very thin bedded calcareous black slate and slaty limestone occur to the west. Opposite a large erratic block on the south bank, there is 2 m thickness of limestone breccia containing calcarenite to micrite and black slate clasts, in a slaty matrix. Bedded micrites of varying nodularity, 1-10 cm thick, are found in calcareous dark grey to black slate above this breccia. Some thicker micrite lenses in this interval are associated with soft-sediment disruption. At the east end of the stone foundation of an old mill, there is a rapid gradation from dark grey and black to green slates over a meter or two. Micrite, mostly in disconnected nodules, occurs on both sides of this contact in a similar manner to the same one seen at Stop 2, between Browns Pond Fm and Mettawee Slate Formation.
If the water is high, it will be necessary to go up the bank and around the outcrop of green slate under the mill foundation. Some thin calcisiltite and a few calcarenite beds occur in the green slate; no purple slate exists here, as is the case in many places, particularly on the western side of the area. The slate becomes greyish in its upper part and just to the west of a small cave in the outcrop, there is a contact with black slate of the overlying unit.
This might be mapped as West Castleton, since laminated calcarenites, calcisiltites and micrites are exposed within the base of this black slate. However, they form a very thin interval and are succeeded, close to another stone wall foundation, by orange-weathering dolomitic sandstone and quartzite beds typical of the Hatch Hill Formation. These can be found in fairly continuous outcrop, with decreasing dips to about 10°E by the parking lot. The thicker arenite beds here are at about the same stratigraphic level as those seen at the beginning of Stop 4 on Tanner Hill Road.
To the west along the river, there is reasonably good exposure along the south bank, exposing Poultney Formation from a short distance west of the parking lot. We will not visit this part of the section. Instead, walk (if on bus trip) or drive back to the road, turn left and cross the bridge. Park cars on the left just across the bridge, and find the footpath down to the river on the west side of the road. STOP 5B. Dark slabby cherts of the Mt. Merino Formation are exposed under the bridge. To the east of the bridge, pale green slates are assigned to the Indian River. The cherts are somewhat disturbed by minor faulting. To the west, across an unexposed interval, outcrops of well-bedded silty and sandy graywacke with interbedded grey slates belong to the Pawlet Formation. These are better exposed on the north bank, where inverted sedimentary structures can be found, but it is not feasible to take a large group there.

STOP 6: Stoddard Road Thrust
Park on left just before pond. Ask Permission at farmhouse on corner.
At this stop we will visit outcrops of Indian River, Poultney, and Pawlet Formations. Indian River and Poultney Fms. lie on the western (lower) limb of a large F1 syncline which is cored by Mount Merino Fm. (not visited). The lower limb of this syncline is thrust westward over Pawlet greywackes which lie in the core of an F1 syncline to the west. This stop is important because here a thrust relationship can be unequivocally demonstrated due to the well constrained stratigraphy and regional structural framework. Equally important is the presence of fault or at least fault-related rocks in outcrop. Mesoscopic and microscopic examination of these fault-related rocks constrain the timing and style of faulting in this area. The stop also demonstrates that caution is necessary in statements concerning the density of faults in regions where stratigraphy is less well constrained.
Indian River; hard, green, well cleaved, porcellanous slates, crop out alongside Stoddard Road and south and immediately adjacent to the pond. The small abandoned quarries to the north of the pond are in the Indian River. To the west of the Indian River are a series of low outcrops of gray-green, less fine grained argillites and slates with interlayered, thin silty quartzites, characteristic of the Poultney Formation. A short distance to the west-northwest is a steep, 1-1.5 m high ledge of medium to dary gray, fine silty, moderately to well cleaved, moderately fissile argillite with thin (0.1-3 cm), silty, often laminated, discontinuous and lensoid quartzites. At the base of the ledge are a series of small outcrops of poorly exposed, though very distinctive, gray weathering, medium to dark gray, medium grained, lithic greywackes of the Pawlet Formation. On the hill to the northwest the greywackes are well bedded and interlayered with dark gray slate.
The 1-1.5 m high ledge outcrop, containing Poultney lithologies, is interpreted to be fault-related. The mesoscopic character of these fault related rocks is more completely described in the structure section above. Important features to note here are: 1) the mesoscopic foliation in the argillite matrix, 2) sharp, tectonic truncations of laminations in the quartzites, 3) shape preferred orientation of the discontinuous quartzites, 4) presence of isolated fold hinges (none have been noted so far), and 5) lack of mineralization, brecciation or other evidence so commonly cited as evidence against the presence of thrust faults in other parts of the Taconics.

STOP 7. (Optional) Complex Stratigraphic and Structural Relations
Stop just beyond white house on right at top of hill. Ask permission at white house
This stop illustrates the problems that result in regions of complex stratigraphic and structural relationships. Specifically the problems here include: (1 ) difficulty of assigning lithologies to lithostratigraphic units in areas where stratigraphic succession is disrupted, even in areas with reasonably good exposure, (2) all contacts are unexposed or at best poorly exposed and thus the nature (sedimentary or tectonic) of the contacts is uncertain, (3) local relationships that are not in accord with regional relations, and (4) problems of distinguishing between preD1, syn- to late D1 or D2 structures.
Very brief lithologic descriptions of each of the outcrops (lettered) is provided below. Possible lithostratigraphic unit assignments are given. Participants visiting the outcrops may thus experience for themselves the local complexities and problems. Structures observable in these outcrops include F1, F2, S1, S2 and local late veining.
(A) Dark gray partly silty argillites with thin silty greywackes. Pawlet.
(B) Black argillite, moderately cleaved. Mount Merino.
(C) Pale green to blue-green (sea green) moderately hard, well cleaved slate. Indian River.
(D) Pale green to pale gray, hard, moderately to well cleaved argillite with thin silty quartzites(?) (possibly tuff bands). To the south, red well cleaved slate. Indian River.
(E) Pale gray to pale green to gray argillite. Indian River.
(F) Medium gray argillite with moderate cleavage. Poultney-top of the Indian River.
(G) Gray weathering, medium to dark gray, fine silty argillite. Poultney .
(H) Same as G.
(I) Gray weathering, medium to dark gray, some almost black, slightly fine silty, moderately-cleaved argillite. Also 25 cm layer of brown weathering gray, fine grained, laminated, dolomitic arenite . Poultney (?).
(J) Gray weathering, dark gray, fine to partly silty moderately cleaved argillite. Poultney.
(K) Gray to dark gray, fine to silty argillite, moderately to poorly cleaved, locally highly veined. Poultney.
(L) Medium to dark gray, fine to partly silty argillite, moderately cleaved, with thin (1-15 mm) silty quartzites. Local bioturbated color laminated slate. A few 2-10 cm thick, brown weathering, fine-grained, dolomitic quartz arenites in medium gray argillite. Poultney.
(M) Pale gray-green, argillite with thin (less than 15 mm) silty quartzites . Poultney.
(N) Gray weathering, pyritiferous(?), dark gray to black siliceous argillite.
(0) Brown weathering, calcareous, medium to fine grained greywacke. Pawlet.
(P) Pale green-gray, moderately soft, well cleaved argillite. Indian River. Just to the north (approximately 3 m), sooty black graptoliferous (poorly preserved) argillite. Mount Merino.
(Q) Medium to dark gray moderately to well-cleaved argillite with some dark gray siliceous mudstones. Poultney(?), Mount Merino(?).
(R) Medium gray, moderately hard argillite. Poultney(?), Mount Merino(?).
(S) Brownish weathering greywacke with minor dark gray slate. Pawlet.
{T) Medium to dark gray partly silty argillite with thin, fine siltstone layers. Poultney.
(U) Medium to dark gray partly silty argillite with thin fine siltstone layers and a few silty quartzites. Poultney. On west side of outcrop small amount of pale green to blue green well cleaved argillite. Indian River (?).
(.V) Medium gray partly silty argillite with moderately to well developed cleavage. Poultney(?) Mount Merino(?).
Regional Picture:
To the south along strike, a well defined east-facing sequence from Poultney to Pawlet lies on the upper (eastern) limb of a large F1 anticline. This limb is truncated to the east by the New Boston Thrust, which juxtaposes Poultney over east-facing Pawlet greywackes. To the north and immediately to the west is a small klippe of Pawlet Formation. Thrusting of the klippe probably occurred as a pre- to early D1 event. The overall distribution of lithologies outlined above suggest the presence of a north or west-facing sequence. This is not compatible with the relationships defined both to the north or the south. For this reason we suggest that the area is dissected by a series of essentially phacoidal thrust faults which give rise to the apparent reversal in facing.

STOP 8:
Stop just before white house on left. Park at roadside. Dirt track making 150° angle with road on right. Walk up this dirt track for - 0.3 mile past outcrops of Pawlet Fm. to contact with Poultney Fm. Follow contact north into woods for -0.1 mile.
The purpose of this stop is to examine a typical section of Pawlet Formation and the complex character of it's contact with stratigraphically underlying lithostratigraphic units. Most workers, including Zen (1961, 1964) Shumaker (1967) and Potter (1972) have argued that the Pawlet Formation unconformably overlies lower Taconic lithostratigraphic units. Shumaker (1967) interpreted the Pawlet contact at this locality to be sedimentary and unconformable, possibly angular. We interpret this contact to be tectonic. Support for this contention include the following observations: (1) complex interleaving of lithostratigraphic units. (2) East-facing Pawlet greywackes just below (topographically) the overturned contact. (3) Regionally, there is a marked apparent thinning from the lower (west) limb to the overturned upper (east) limb of the F1 syncline defined by the Pawlet Formation, suggesting that part of the upper limb has been tectonically excised.
The outcrops visited at this stop illustrate the extreme difficulty of demonstrating the precise nature of this contact on the outcrop scale. The majority of the outcrops are of Pawlet greywackes and slates. Other lithologies include: (1) Dark gray variably siliceous argillites and slates. (2) Medium gray fine silty argillites with thin, mostly silty quartzites. Poultney. (3) Medium to dark gray finely cleaved slates with a silky sheen on cleavage surfaces. Poultney (?). (4) Green, gray and gray-green fine well cleaved slates. Minor thin calcareous siltstone (silty limestones) and quartzites. Mettawee (sensu lato). Figure shows the distribution of lithologies. Numbers refer to the lithostratigraphic units, following the scheme of Figure 1b. Letters refer to the brief descriptions that follow.
Descriptions:
Start at small roadcut on the main road 10 m south of H. & H. Slate Co. quarry access road.
A - Greywackes and slates. Folded by F1, moderately NE plunging fold with an axial surface slaty cleavage. Note cleavage refraction through greywackes. Moderately developed steep spaced crenulation cleavage. Veining and late disruption of the south end of cut.
B - Low outcrops on the east side of access road. Greywackes and slates. East-facing.
C - Bulldozed greywackes at the first turn.
D - Across small stream, south of C. West part of outcrop, east-facing bedded greywackes and slates. Central part of outcrop, deformed, tectonically sliced greywackes and slates. East side of outcrop, bedded, east-facing greywackes and slates in gently south plunging antiform.
E - Bedded greywackes, bounding steep zone of veined and disrupted greywackes.
F - Bedded greywackes and slates. Slates more abundant. Bed thickness varies from a few to 10's of cms. Fresh greywacke exposed at corner. Note medium grain size and lithic component.
G- Very small, mostly covered outcrop of greywackes and slates.
H - More greywackes to the north of access road.
I - Small outcrop of thinner (4-8 cm) greywackes and slates. Possibly west-facing.
J - Another outcrop on the east side of the access road, same as I.
K - Contact. Three lithologies present, from west to east these are: discontinuous, west facing(?), greywackes and slates. Dark gray, variably siliceous argillites and slates, some chert. Interlayered medium gray fine silty argillites and thin, fine grained to silty quartzites, typical Poultney. The thin siliceous lithology is often observed at this contact. Contact appears sedimentary at this outcrop.
L - Predominantly medium gray argillites and slates with thin quartzites. Poultney.
M and N - Bulldozed cut in medium to dark gray slates, thin calcareous siltstone layers, thin quartzites and minor Pawlet-like greywacke. Relationships of lithologies not clear, but probably tectonic. Second generation structures prominent.
O - Small outcrops along jeep track, taking off to the north of the access road. Lithologies include gray to dark gray slates, greywackes, gray, green and gray-green slates, some slates with thin quartzites, some dark gray siliceous slates.
P- Scattered outcrops of finely cleaved medium gray slate (Poultney?). Locally highly veined.
Q - Chalky weathering, medium to dark gray, variably siliceous argillites. Brecciated chert. Greywackes downslope .
R - Graywackes
S - Same as Q. Note greywackes and small amounts of gray slate with thin quartzites 1 m below ledge. Also, in bottom part of ledge of siliceous argillite a 'layer' of greywacke lithology truncates the siliceous lithologies across at least the cleavage. This greywacke 'layer' does not possess bedding characteristics and is not believed to be of primary sedimentary origin. Other possibilities include injection or tectonic slicing.
T - Downslope to the southwest of R, small outcrop of medium gray slates with thin quartzites, typical of the Poultney. Greywackes occur both above and below this exposure.
As you can see simple contacts cannot be drawn in this area.

A9: MARINE AND FLUVIAL DELTA PLATFORM ENVIRONMENTS OF THE TRANSGRESSIVE CLASTIC CORRELATIVES OF THE MIDDLE DEVONIAN (ERIAN) MOTTVILLE LIMESTONE MEMBER OF THE SKANEATELES FORMATION IN EASTERN NEW YORK STATE
Fred Wolff
Assoc. Prof., Geology Dept., Hofstra University, Hempstead, New York, 11550
Peter J.R. Buttner
Director of Environmental Management
New York State Park System
Central Office
INTRODUCTION:
In west-central New York, the base of the Skaneateles Formation is in arenaceous limestone and coquinite designated by Smith (1916) as the Mottville Limestone. When traced eastward toward Kingston, N.Y., this unit and the associated calcareous siltstones thicken and grade into lenses of calcareous, planar crossbedded sandstones and dark gray laminated and bioturbated shales and coquinites, without the diagnostic faunal correlatives (Grasso and Wolff, 1977).
The sequence is interpreted as a zone of carbonate deposition (organic and inorganic) formed on the marine delta platform during a temporary clearing of the Proto-Atlantic seaway. Eastward this clearing produces a short transgression enabling a reworking of the sandy sediments on the marine delta platform to produce a series of offshore and nearshore sand bars and associated embayments. A major embayment located between two nearly-merging lobes of the alluvial delta platform forms an area of practically restricted circulation producing a variety of shallow water environments (nearshore and river mouth bars, sand flats, channels, beaches) and restricted environments (irregular shelf ponds, lagoons, mudflats, interdistributary bays and swamps). These "transgressive" sediments are abruptly truncated by a sequence of gray "channel" sandstones and "overbank" olive-green to maroon silty shales - the return of distributary progradation as the rivers of the classic Catskill Delta Complex once again spill their sediments across the subsiding basin.
This field trip will examine the transgressive and restrictive nature of the marine sediments that are wedged between the initial redbeds of the Catskill delta. Some of these stops and environments described here have also been described elsewhere. (Buttner, 1968; Wolff, 1969 ; Pedersen, Sichko, Wolff, 1976)

A9: MARINE AND FLUVIAL DELTA PLATFORM ENVIRONMENTS OF THE TRANSGRESSIVE CLASTIC CORRELATIVES OF THE MIDDLE DEVONIAN (ERIAN) MOTTVILLE LIMESTONE MEMBER OF THE SKANEATELES FORMATION IN EASTERN NEW YORK STATE

Outcrop of Otsego Shale

STOP 1. Rt. 143 west of Dormansville
Units - Solsville Member; facies - Chemung; depositional environment - nearshore marine delta platform in marginal embayment (Albany Bay)
STOP 1A - Quarry on N. side of road near home of Mr. M. Rossner
Park in wide driveway near crest of hill at home of M. Rossner
Description: While a few 0.2-0.5 meter planar crossbedded sandstones appear somewhat lower in the section, this is the first major lenticular sandstone in the area. The 2-meter sandstone has crossbeds, thin laminations, and local truncation surfaces. It contains a few bivalves (Cypricardella) lateral bioturbation structures, mud clasts, and plant fragments. The planar crossbedding trends N. 70° W - S 60° E, suggesting an onshore-offshore current influence. The sandstones are interpreted as prograding river mouth bars. The section is unique because strata at this interval are red beds in the adjacent quadrangles - the marine Marcellus being nearly 60 meters thicker than sections to the west and south. The area has been termed "Albany Bay" by Goldring (1943) - see Figure 7.
STOP 1B. Quarry on Lobdell Mills Road across Rt. 143.
Drive across Rt. 143 to dirt road opposite driveway (Lobdell Mills Rd.) and park at first quarry on left
Quarry consists of 2 meters of medium-dark gray siltstone and shale with several Mucrospirifer coquinite horizons. Associated fossils include a diverse assemblage consisting of: Camarotoechia, Athyris, Chonetes, and the bivalves Modiomorpha, Paracyclas, and Grammysia. Flat bedded, fine-grained sandstones with coquinites are common in the Dormansville-Westerlo area at an elevation of 1200-1300 feet, suggesting brief periods of strong agitation in relatively shallow water. The abundance of sessile epifaunal filter feeders suggests an abundance of suspended organic matter in deep quiet water. These contrary interpretations may be resolved by considering the embayed marine platform to also contain localized sandy shoals and broad muddy lagoons. A 0.8 meter crossbedded calcareous sandstone occurs on the N. side of Rt. 143 0.3 miles west of here (8 meters higher in the section) and this is believed to represent the clastic correlative to the Mottville in this region (Wolff, 1969).

STOP 2. Rensselaerville Falls. Edmund N. Huycks Preserve
(Walking tour - cameras only; no hammers please)
Units- Solsville, Mottville correlatives, Panther Mt., Plattekill; facies - Chemung and Catskill; depositional environment - marine delta platform, brackish lagoonal (interdistributary), and floodplain - alluvial channel.
Description: The 22 meter section below the roadway bridge consists of flat, thick-bedded to massive sandstones or low-angle planar crossbedded sandstones interbedded with dark gray silty mudstones and shale - lithologically and stratigraphically similar to the Solsville Sandstone section at Stop 1, but without the coquinites. In the park, the section below the falls consists of 1-2 meters of medium-grained sandstones with some sinuous ripples (crests trend N 50° W). These may represent the top of the Solsville, though the presence of Pterinopectin macrodonta suggested the lowest Skaneateles (Mottville?) to Goldring (1943 p. 266 and 268).
The lower falls contain megarippled sandstones capped by a light-gray, bar-like, 1-1.2 meter crossbedded sandstone with cross sets trending S 70° W (3°) and N 70°E (15°). These are unique - the only such sandstones with such an internal and external geometry within either stratigraphic formation - see Figure 8A. They are interpreted as reworked river mouth or nearshore sand deposits formed during the clearing of the seas that produced the Mottville Limestone.
In ascending the falls, note that the bars are overlain by 16 meters of fine-grained, flat-bedded thin sandstone and siltstone with thin seams of black shale. These are non-marine strata, formed by vertical accretion, with the black shales containing small ostracods (Beyrichia) and phyllopods (Estheria) that indicate a brackish water environment (Goldring, 1935, p.l64). There is also a gradual color change from medium-gray to olive-gray to mottled olive green-maroon red to red as one ascends the section. The falls are capped by 2.3 meters of gray, medium-coarse grained sandstones that truncate the red mudstone. These trend S 75° W and contain basal clasts of white micrite and red-green mud.
The section is interpreted as one demonstrating the progressive change from open marine to marginal shoal-lagoon brackish water conditions. The persistence of fine-grained sandstone and shale suggest the continual infilling of a marginal embayment - perhaps the continuation of "Albany Bay". The erosional contact at the base of the channel sandstones, with the encroachment of a deltaic distributary from the northeast indicates the start of alluvial sedimentation on the delta platform.
Climb to the top of the falls, cross over the footbridge, climb a short hill, and then return on the trail that descends on the opposite side of the ravine.

STOP 3. Rt. 143 at Franklinton
Units: Mottville clastic correlatives ; facies - Chemung; depositional environment - shoal on nearshore marine delta platform.
Description: This 6-meter section exhibits the interfingering of two en-echelon "bar-like" sandstones that are overlain by 1 meter of fossiliferous dark gray shales. The medium-grained sandstones are light-gray in color (weathers a dark brown) and calcareous with individual planar crossbeds 2-4 cm thick and trending N 50-70° E at slopes of 4-7° (similar to the section at Stop 2 - see Figure 9 on page 22).
The unit coarsens upward and grades into the overlying marine shales which contain Glyptodesma, Mucrospirifer and Camarotoechia. The entire section is 0.2 miles long and is interpreted as a reworking of marine delta platform deposits into these transgressive sand bars on the outer fringes of the prograding deltaic lobe visited at Stop 2 (see also Figs. 2, 4 and 7).

STOP 4A. Rt. 145 S. of Cairo after the junction with Rt.32.
Alternate Stop 4
Unit: Plattekill of the Catskill Facies on the alluvial delta platform.
Description: This 12-meter section represents two upward-fining fluvial cycles well within the Plattekill Formation and illustrates the major difference between the progradational marine sandstone lenses of the platform (Stops 1 and 2), reworked transgressive coastal marine sandstone bars (Stop 3) and the fluvial sandstone channels.
The sands are dark gray, medium-coarse thick bedded (10-30 cm) and planar-crossbedded depositional units with infrequent scour and fill pockets across a sharply truncated megarippled surface. Plant fragments and olive-red mud clasts are common.
The gradational nature of the massive, irregularly bedded sandstones into gray-red silty mudstone indicate, through channel abandonment, the gradual change from channel to levee to floodplain environment. This rhythmic pattern is prevalent through the next 400 meters of section in the nearby Catskill Mts. The dominance of gray channel sandstone over red floodplain siltstone-mudstone at this interval suggest rapid seaward delta progradation of many distributaries, with relatively little vertical accretion in floodplain and interdistributary bay environments. Gradients were probably low, but the large scale megaripples and scour suggest high current velocities and perhaps gently curved rather than true meandering rivers. In places, channel deposits directly overlay earlier deposits of similar origin, indicating complete lateral and vertical erosion of the overbank red mudstones and a nested sequence of irregular, sub-parallel distributary channels prograding into the basin.

STOP 4. On Catskill Creek off Rt. 145 and Rt. 23B near Leeds
Units: Mottville and Plattekill Members; facies - Chemung and Catskill; depositional environment - marginal fluvial and fluvial .
This section is stratigraphically similar to the one at Stop 2 Rensselaerville Falls) but begins within a 4-meter upward-fining sequence of planar crossbedded channel sandstones overlain by olive gray and dull maroon mudstones and shales as overbank and floodplain deposits. This first fluvial cycle also has the first "redbeds" of the Plattekill Formation. North and south of this area the first fluvial deposits are not red, and the thickness of this non-red alluvial sequence increases to locally form the Ashokan Member. Nearly all of the important flagstone quarries in this region came from the Ashokan. The unit consists of flat-bedded and low angle planar and trough crossbedded sandstones with sharp basal contacts and an abundance of mud clasts and plant fragments. The associated olive and gray shales rarely contain marine fossils.
The Ashokan Member is distinguished from the Plattekill by the lack of redbeds, the dominance of medium-sized (2-4 cm) flat-bedded sandstones (as flagstone) and the dominance of thinly laminated flat-bedded sandstone. These criteria along with current lineation, bioturbation, mottling, load casts, and lateral sediment associations suggest the development of extensive sand flats and marginal channels between the major deltaic lobes (Figures 3 and 7).
Above the initial fluvial sequence are red-green mottled sandstones and some thin seams of black shale with ostracods (Beyrichia). The overlying 3 meter section consists of gray-green flagstone, massive, calcareous sandstone with mud clasts, and interbedded slumped and bioturbated sandstone with an erosional top. This represents a short "upward coarsening" sequence, with some period for reworking and burrowing by organisms before erosion, and is taken to represent a tidal or super-tidal sand flat and also the clastic correlatives to the Mottville interval in this area. Above this truncation the next 6 meters consist primarily of light-gray-olive green siltstone mudstone and shale, with abundant plant fragments and believed to represent overbank disposition as marsh deposits above the sandflats. These mudstones are truncated by a 1.6 meter section of planar crossbedded gray sandstones with megaripples, scour and fill pockets, load casts, and some bioturbation - the return to fluvial conditions. It is overlain by the typical sequence of gray to olive-green to maroon-red mudstones and shales - the second fluvial cycle. Figure 9. Planar crossbedded light gray calcareous sandstones of en-echelon "bar-like" Mottville Clastic Correlatives on Rt. 145 at Franklinton (Stop 3).
The correlation of the light gray calcareous crossbedded sandstones as 'Mottville correlatives" is based partly on the unique lithology within the fluvial section but more so on the position of this unit between the first two fluvial cycles, as will be re-examined at Stops 5 and 6 when we again view this interval within an embayment.

Roadcut between gas stations
Slow down at roadcut between gas stations and stop on roadside

STOP 5A. off Rt. 32 near
Units - Upper Mt . Marion (Solsville), Mottville correlatives, and Ashokan; facies - Chemung; depositional environment - nearshore marine, marginal channel and sandflats. Stop 5A - Along Rt. 32 before junction with County Rd. #36, and at quarry near town garage on Rd. #36.
Description: The top of the section (on Rt. 32) contains extensive flat-bedded and low angle planar crossbedded and laminated gray sandstones (Unit C) - the type used for the flagstone industry that has dominated this region for the past 75 years. These truncate a 1.2 meter section of massive calcareous sandstones and olive mudstone (the Mottville clastic correlatives - Unit B) that are underlain by a 1.8 meter interval of megarippled and planar crossbedded and laminated sandstones with mud clasts and scour and fill pockets, and massive flat-bedded sandstones - Unit A. Here too the clastic correlatives form marginal sand flat or marsh environments between two marginal or fluvial channels (as at Stop 4).
The quarry on County Rd. 36 consists of 2 meters of thin-bedded planar crossbedded gray sandstone (Unit A) overlain by an 0.5-0.8 meter undulatory surface with scour and fill structures, in turn overlain by a 1.3 meter light gray calcareous, crossbedded sandstone (Unit B).
The laminated flat-bedded and cross-bedded sandstones are interpreted as tidal sand flats and beaches fronting the deltaic marshes. The megarippled surface and scour and fill with pockets of olive mud-stone add support to this, the upward fining sequence suggesting the filling in of a shallow embayment behind the tidal sand flats. The overlying laminated and slightly sorted "bar-like" sandstone represents the reworking of the sandflats into a shoal or beach (Unit B). The truncation of this sequence by the next series of gray crossbedded sandstones with basal mud clasts and plant debris suggests the presence of a marginal channel or river mouth bar. The large tree molds (Wolff, 1969) indicate a close proximity to the seed fern forests that inhabited the local coastal swamp.

STOP 5B - On Rt. 32 below junction with County Rd. #36.
This 24-meter outcrop consists of massive marine sandstones and dark gray shales with several horizons of ball and pillow structures (Figure 10). It is known locally as the Mt. Marion Formation and is correlative with the Solsville Member of the Marcellus Formation. Other characteristic features include long, low angle planar foresets, coquinite horizons and the thin but persistent 7 cm Alcove Conglomerate that can be traced to Stop 1 at Dormansville. The section (as at Stop 1) represents the marine delta platform with the ball and pillow structures interpreted as load casts developed from sediment foundering during earthquake activity. The seismic tremors could also create tsunami which extend into the embayments and channels and transport the marginal and fluvial deposits (and the pebble bed) onto the marine platform (Wolff, 1977). A possible Middle Devonian astrobleme may be buried within the Catskill Mountains only 9 kilometers from this outcrop (Isachsen, Y.W. et.al. 1977) suggesting an even more extreme origin for these deposits.

STOP 6. Rt. 212 near Centerville
Units - Mottville Correlatives and Ashokan Member; facies - Chemung; depositional environment - marginal marine and fluvial.
Description - Here the suggested Mottville correlatives are sandwiched between the first two marginal channels or river mouth bars (See Figure 11). The lower 2.2 meter section consists of medium-grained planar crossbedded gray sandstones with basal mud clasts directly overlying marine strata. The unit is overlain by 0.3 meters of dark shale and 1 meter of massive light gray sandstone.
The next 4.5 meters comprise the Mottville correlatives and consist of 2 meters of alternating massive gray calcareous sandstones and dark shales with bioturbation markings and load casts. These are truncated by 2 meters of thinly laminated and crossbedded sandstone, 1.3 meters of massive light gray calcareous sandstone, and 1.2 meters of interbedded fine-grained sandstone and dark shale with flaser bedding. The sequence ends with 1 meter of rippled sandstone and shale with extensive lateral worm burrows. (Figure 12)
The outcrop is capped by an 8 meter sequence of thick beds of gray planar crossbedded sandstone with megarippled surfaces and abundant mud clasts.
The lower sequence shows small scale polymodal trough cross bedding and lamination suggesting the periodic reworking of a marginal channel or river mouth bar. The middle section with the massive, crossbedded and cross laminated calcareous sandstones, ripples, flaser bedding and bioturbation suggests the preservation of intertidal sand flats, and shallow lagoons. The massive crossbedded and burrowed light gray calcareous sands may indicate the pressure of a beach or reworked sand flat environment. This short interval of marine resedimentation is sharply truncated by the overlying fluvial progradation that nearly erodes this transgressive sequence. However, the persistence of these unique reworked deposits both to the north and to the south of this region (Wolff, 1969) and to the west (Grasso and Wolff, 1977) indicates that the extension of the Mottville clastic correlative is possible through these unique lateral sedimentary associations.

A10: STRATIGRAPHY, STRUCTURE, AND THE MINERAL WATERS OF SARATOGA SPRINGS - IMPLICATIONS FOR NEOGENE RIFTING
James R. Young
Dunn Geoscience Corporation
Latham, New York
George W. Putman
State University of New York at Albany
Albany, New York
The carbonated mineral springs of Saratoga have been the object of considerable interest ever since their discovery by colonists in the late eighteenth century. The three major previous studies (Kemp, 1912; Cushing and Ruedemann, 1913; and Colony, 1930) express the crux of the problem as we see it today. Foremost, among these, is the abundant CO2 gas and the difficulty of explaining its presence in such large amounts by known shallow, oxidizing mechanisms of generation, or by hydrolysis reactions involving carbonates, the reasons for which will be partially addressed below and further during the field trip. The only known applicable methods remaining are thermal: 1) either direct degassing of an igneous melt or decarbonization of carbonate rocks adjacent to an intrusion, or 2) decarbonization in water-rock equilibria during metamorphism. Recourse to the former mechanism in terms of cooling Paleozoic plutonism has been taken by all three of these earlier workers because of chemical inconsistencies that are also incompatible with low-temperature methods of CO2 formation; i.e., negligible sulfates, nitrates, and phosphates. This interpretation presents an apparent paradox for all known igneous activity in the Northeastern United States ceased with dike swarms in the middle Mesozoic--about 100 million years ago. Since it is now known that anomalous convective and conductive heat flow from this time should have long since ceased allusions to dying metamorphic or igneous fires from the past are not a really very satisfying explanation; indeed, they have only served to deepen the mystery.
We must ask then, are the waters and gas at Saratoga really thermally generated; and, if so, how can we understand the source of the thermal processes in more definite terms?

A10: STRATIGRAPHY, STRUCTURE, AND THE MINERAL WATERS OF SARATOGA SPRINGS - IMPLICATIONS FOR NEOGENE RIFTING

Pass over pre-glacial Mohawk River Channel

Pass excellent road cut exposure of Utica Shale cap rock.
Stopping not permitted

McGregor Fault scarp on left

Small exposure of Paleozoic carbonates
Small exposure of Paleozoic carbonates in creek bed (Snook Kill) at Junction. Proceed up McGregor Fault Scarp.

STOP 1. Precambrian paragneiss and quartzite
Precambrian paragneiss exposed in roadcut. Note almandine garnet and sillimanite needles parallel to the foliation planes.
Precambrian metasedimentary quartzite unit exposed in streambed .

STOP 2. (one hour)
Pompa crushed stone quarry
Excellent exposures of the Gailor and Galway Formations, a variety of sedimentary features, and several fault zones. Note upper-most Gailor novaculite zone, Hoyt unconformity, vuggy zone with quartz crystal fillings, karst breccia fillings, and fault gouge.

STOP 3. (15 minutes) Lester Park
Well preserved specimens of cryptozoa of the Hoyt formation. Note its position at the lip of another fault scarp.

State Park and Bottling Plant
Saratoga Springs State Park to the east and Saratoga Vichy bottling plant on the west

Hathorn #3 mineral well on the left.

STOP 4. (45 minutes) Walk up Geysers Brook
Disembark and walk up Geysers Brook passing the Polaris, Karista, Hayes, Island Spouter mineral wells. The Ferndell spring on the right is normal surface groundwater. Continue up the brook to the Orenda well and picnic area.

Lunch stop. 12:00 p.m.
Discussion of the chemistry of the waters. pH and temperature measurements of the Orenda well and several others. Note the large tufa mound from the Orenda discharge.

State Bottling Plant on right.
Pass old State Bottling Plant on right. Site of Geyser and State Seal wells.
2015: This is now an auto museum.

Lincoln and Washington baths on the left.

STOP 5. (10 minutes) Grand Union Motel - Rosemary well
Grand Union Motel on the right is the site of the anomalous Rosemary well. pH and temperature measurements of the water and a brief discussion of the significance of its different chemistry.

Hathorn #1 Mineral Well on corner

STOP 6. (15 minutes) High Rock and Peerless springs
High Rock and Peerless springs are across the road from one another. The natural High Rock is at the base of the Saratoga Fault scarp, a continuation of the McGregor Fault

Old Red Spring

B1: ECONOMIC GEOLOGY OF THE HUDSON RIVER VALLEY
George M. Banino
William E. Cutcliffe
Dunn Geoscience Corporation
Latham, New York
The purpose of this field trip is to examine some of the economic uses of the rock and mineral deposits of the Hudson River Valley, and to discuss the importance of economic geology in helping to bring these commodities to the market. The area we will study has a wide variety of economic deposits and mining operations, all of which are related to the construction industry. This is in part due to the location near major metropolitan markets and the presence of a major transportation route, the Hudson River, but is basically controlled by the nature and location of the geologic deposits.
During this trip four sites will be examined, each producing a different product, and each with a different geologic setting that must be considered in the mining process. The sites to be visited are Norlite Corporation, Cohoes, New York, producing lightweight aggregate; Atlantic Cement Co., Ravena, New York, producing portland cement; Callanan Industries, Port Ewen, New York, producing construction aggregate; and another portion of the Callanan property producing sand for bituminous concrete.
There is a long history of geologic work in the Hudson River Valley, going as far back as Amos Eaton in the first quarter of the 1800's, which has led to a large volume of geologic studies and innumerable field trips. This guidebook draws principally from three previous trips, the 33rd New York Geological Association trip in 1961 (Dunn & Rickard, 1961), the 61st New England Intercollegiate Geologic Conference in 1969 (Brown & Cutcliffe, 1969), and the 14th Annual Forum on the Geology of Industrial Minerals in 1978 (Banino & Brown, 1978).

STOP 1. Norlite Corporation
The Norlite Corporation, a subsidiary of P.J. Keating Co., Lunenburg, Massachusetts, produces expanded shale aggregate, or lightweight aggregate, by a rotary kiln process. The property consists of the deep quarry and manufacturing facility. The Snake Hill shale which is quarried is overlain by glacially derived overburden consisting of clay, silt, and cobbles, which are stripped off prior to drilling and blasting.
Geology
The Snake Hill is a thick sequence of shale with occasional mudstone and sandstone beds. As revealed in the quarry and drill core, the rock is a monotonous sequence of medium dark gray to dark gray, very fine grained shale with occasional thin beds of convoluted mudstone or very fine sandstone. Overall, bedding dips about 50 degrees to the southeast and cleavage dips about 60 degrees to the southeast.
Close inspection of the quarry reveals more detailed structural features. Where bedding is sufficiently apparent, the noses of isoclinal folds can be observed, particularly where the rock is more of a siltstone than a shale.
Along the west wall of the quarry, one of several faults can be observed. This fault cuts the rock at a lower angle than either the bedding or the cleavage. The age of the faulting is not known.
Manufacturing
Norlite lightweight aggregate is a manufactured product in which crushed shale is expanded to produce an aggregate used, normally, for Portland cement concrete. The advantage of this product is its reduction in weight as compared to normal weight aggregate. This allows the production of lightweight concrete, either for small structures to be moved by hand, such as concrete blocks or curbing, or for structural concrete, particularly in tall buildings where there is a considerable savings in reducing the total weight of the building. Typically a cubic foot of Norlite coarse aggregate weighs 45 pounds compared to about 100 pounds for regular weight concrete.
Expanded shale aggregate also has several other properties that make it attractive for specific uses. Because lightweight aggregate contains very small separated air cells, it has enhanced insulatory value. The air cells greatly enhance the thermal resistance (R value) of concrete, so that lightweight aggregate concrete has the capability of providing over twice the thermal insulation of normal weight concrete . Also, because all combustible material has been burned out in the manufacturing process, the fire resistance of lightweight aggregate concrete is greater than that for natural aggregate concrete.
The basic process in expanding shale is the introduction of crushed shale into an oil fired rotary kiln where temperatures in the burning zone are maintained between 2000 and 2100 degrees Fahrenheit. At this temperature the shale reaches what is known as the point of incipient fusion where the shale is in a semi-plastic state and gasses are generated by the breakdown of carbonates and oxides. The gasses are generated but contained within the semi-plastic mass, expanding the shale and creating individual non-connecting air cells. As the material is passed out of the kiln, it is air quenched to form a vitreous clinker that is then recrushed and sized to make the final product. Figure 3 is a plant flow diagram of the Norlite process.

STOP 2. ATLANTIC CEMENT COMPANY
Atlantic Cement went into production in 1960 following detailed geological analysis which preceded the investment of $44,000,000. There are three major quarries on the property: the Becraft quarry, the North Coeymans-Manlius quarry, and the South Coeymans-Manlius quarry. Adjacent to these are several other mining faces, including the high face of the Esopus shale and lower benches in the Kalkberg. The Becraft and Coeymans-Manlius quarries provide the high-calcium limestone for cement while the Esopus face provides an alumina additive and the Kalkberg is stripped to gain access to the Coeymans-Manlius.
The Kalkberg is a New York State Department of Transportation-approved coarse aggregate source. However, an aggregate processing plant has never been established here. Because the Kalkberg that is being removed is a future resource, it is placed separately in stockpiles for possible future use. The top of one of these stockpiles is undergoing reclamation, though it is realized that it may be disturbed later.
The Coeymans-Manlius face is excavated from a few feet above the RondoutManlius contact, to avoid incorporating the dolomitic Rondout in the shot, to about ten feet above the Coeymans-Kalkberg contact. Silica from the Kalkberg requires some adjustment of the design mix, but this increases reserves and decreases the amount of Kalkberg that must be removed.
STOP 2a
The walls of the access ramp of the North Coeymans-Manlius quarry expose a complete section from the Rondout to the Lower Hannacroix member of the Kalkberg formation. The contact of the Rondout with the underlying Normanskill shale is at the water level of the sump at the bottom of the ramp. The Rondout can be seen to be about four feet thick, increased over its normal two foot thickness by faulting. The Manlius units and Coeymans are well-exposed along the ramp. Note the gradational contact of the Coeymans and Lower Hannacroix near the top of the ramp where chert can be seen on both sides of the contact.
STOP 2b
The full section of Becraft is exposed in the Becraft quarry. The lower contact is gradational but can be placed about two feet below a discontinuous blue-gray chert horizon that can be found on the face. The high shale face above the Becraft is in the Esopus formation which is used as an alumina and silica source. Below the Esopus, the upper two feet of the Becraft face in places reveal the remnants of the Alsen, Port Ewen, Connelly and Glenerie formations that are fully developed at the Callanan quarry. A high-angle thrust fault, with relatively minor displacement, is located at the north end of the quarry. The area around this quarry has well developed synclinal ridges, with the youngest unit, the Esopus, forming the ridges and the high-carbonate Becraft forming the valleys which occasionally contain wetlands.
STOP 2c
The access into the South Coeymans-Manlius quarry displays a complex local structure. This exposure is at the northern end of a major thrust fault, at the point where the displacement is small enough that the rock has failed by folding rather than by faulting. The black chert bands of the Lower Hannacroix mark the asymmetrical anticlinal fold. However, the bedding is largely obscured by very well developed fracture cleavage. There is marked thickening of the beds along the fold crest as a result of slippage along the cleavage surfaces.
2015: The Ravena plant was originally Atlantic Cement. It later became known as Blue Circle. Lafarge merged with Blue Circle in 2005.

STOP 3 -- Callanan Industries, Inc. Port Ewen
Crushed Stone Quarry
The Port Ewen quarry is owned and operated by Callanan Industries, a subsidiary of Penn Dixie Corporation. The principal product is New York State Department of Transportation approved coarse aggregate (crushed rock). Within the past five years a small fine aggregate (sand) operation was initiated to produce asphaltic sand for the company's asphalt plant located on the property.
Two crushed stone products are produced; high friction bituminous concrete aggregate, and portland cement concrete aggregate. The reserves are within the Lower Devonian Helderbergian rock units .
High friction aggregate is specified by the New York State Department of Transportation for use in top coarse asphaltic concrete pavements to obtain an aggregate that does not polish when exposed to heavy traffic. High friction aggregate specification requirements are divided into non-carbonate and carbonate rock types. Most non-carbonate high quality rocks such as granites, diabases, and quartz feldspar gneiss, can be used as high friction aggregate and also as a 20% blend to upgrade high quality aggregate that does not otherwise meet the high friction aggregate specifications.
The second classification, carbonate rocks, which the entire Port Ewen quarry sequence falls within, to meet high friction aggregate requirements either must contain 10 percent material plus 100 mesh insoluble residue in concentrated hydrochloric acid (presumably quartz) or contain 20 percent non-carbonate material (chert).
Ten formations are mined at the Port Ewen operation. They are the upper two units of the Rondent, Manlius, Coeymans, Kalkberg, New Scotland, Becraft, Alsen, Port Ewen, Connally, and Glen Erie formations. With the exception of the Connally formation which is a calcareous sandstone, all of the other formations are either dolomitic limestones (Rondent and Manlius), high calcium pure limestones (Coeymans and Becraft), cherty limestones (Kalkberg, Alsen and Glen Erie) or argillaceous limestones (New Scotland and Port Ewen formations).
Listed below are the formations and their uses:
Formation | Approximate Thickness | Use |
Glen Erie
Regular Aggregate - High Friction
Upper High Friction Sequence
Connally | 15 | Regular Aggregate - High Friction
Port Ewen | 100 | Regular Aggregate - High Friction
Alsen | 20 | Regular Aggregate |
Becraft | 40 | Regular Aggregate |
New Scotland | 115 | Regular Aggregate - High Friction | Lower High Friction Sequence
Kalkberg 65
Coeymans | 20 | Regular Aggregate |
Manlius | 50 | Regular Aggregate |
Roundot (2 units) | 40 | Regular Aggregate |
The two products must be mined, processed, stockpiled and delivered separately. Plant production demands necessitate maintenance of separate operating faces and loading units for each product. For example, high friction aggregate will be mined from two separate faces for two or more 8-hour shifts followed by regular aggregate production from two additional faces for several shifts or days.
Structure
The Helderbergian limestone formations are intensely folded and faulted. The initial stop at this site will be in the northeastern portion of the quarry where the lower Rondout, Manlius, Coeymans, Kalkberg, and New Scotland vertical beds are forming the east limb of north-south trending syncline which plunges to the north. The Becraft, Alsen and Port Ewen formations are complexly faulted in the northeastern portion of the quarry and challenge certain geological interpretations without additional subsurface drill hole information.
The northern face exhibits several moderate angle thrust faults in the Glen Erie, Connally, and Port Ewen formations. The distinctive Connally calcareous sandstone unit makes an excellent marker bed to discern the structural relationships.
In the western portion of the quarry a major thrust fault has been mapped and mined during the past twenty years. The eastward dipping thrust sheet has caused numerous mining stability problems.
Quality of Products
New York State Department of Transportation requirements for high friction aggregate demand that only the approved formations be included in that product. This demands good quality control beginning with well defined geology, ongoing mine planning and regular production control.
Dunn Geoscience Corporation personnel are retained to complete biannual geologic source reports which represent in both map and cross section form the areas of proposed operation for the next two years of both products by formation boundaries. In addition, the boundaries of each product are marked with spray paint on the faces and targets are set on the upper levels to indicate the orientation of the third dimension extension of the contact.
A mine plan has been completed by Dunn Geoscience Corporation to allow annual and monthly planning to be fitted into a long term mining and reclamation plan. Triennial reclamation plans are required and submitted to the New York State Department of Conservation
Market
The large majority of the finished products are barged to New York City via the Rondout Creek and Hudson River. The crushed rock and fine aggregate that is supplied to the Callanan asphalt plant is used within the local region.
Sand
The sand deposit appears to be an upland erosional remnant of a formerly larger deposit. Similar material can be found on the east side of the railroad tracks and to the north along the north valley wall of Rondout Creek at Wilbur, New York.
The source is glacio-lacustrine in origin, displaying a single mode of deposition. The several local deposits exhibit similar structure suggesting that the depositional environment was fairly extensive in the Rondout-Hudson Valley region. Damming by glacial ice in the Hudson River valley is believed to have created a lake both in the Rondout and Wallkill River valleys that extended to the south to within 2.5 miles of New Paltz, New York.
Material composition and bedding configurations suggest that the Port Ewen deposit was laid down in a pro-delta glacio-lacustrine environment. The slight coarsening upward and distinct bedding indicated either a slight shallowing of water or an advance of the sediment source into the lacustrine environment. The aeolian sand probably represents final deposition in the pro-glacial zone as lake waters receded.
The soil layer and the aeolian fine sand is stripped from the proposed area of operation. The sand deposit is removed by front-end loader, into trucks, and hauled to the asphalt plant site where it is stockpiled and blended as needed. The gradation and quality of the deposit is such that no additional processing of aggregate is required.
Material from the source primarily is used to make bituminous concrete aggregate as required.

B6: DEGLACIAL EVENTS IN THE EASTERN MOHAWK - NORTHERN HUDSON LOWLAND
Robert G. LaFleur
Troy, New York 12181
The Mohawk Lowland extends some 90 miles east from Rome to the modern Mohawk's junction with the Hudson River at Cohoes (Figure 1). Woodfordian ice advancing south and westward through the Hudson-Mohawk Lowland emplaced the Mohawk till and formed an extensive drumlin field on older drift. A variety of deglacial events included lake development, glacial readvances, large-scale Great Lakes through-drainage, and subdued river flow. This history becomes complex to the east because pulses of the Oneida lobe alternating with lake outbursts in the western Mohawk basin influenced discharges into Lakes Albany and Vermont in the Hudson Lowland (LaFleur, 1975; Hanson, 1977).
A series of active ice-margin positions, recognized in the Schoharie Valley, are associated with the development of glacial Lake Schoharie (LaFleur, 1969). See Figure 2. In the Hudson Lowland, well-defined, progressively younger ice margins defended northward-expanding Lake Albany which maintained an elevation of about 330 feet at the latitude of Troy. However, tracing of ice-border positions westward through the Mohawk Lowland has proven difficult. Because the broad interfluve of the Helderberg upland did not receive ice-contact deposits in abundance, it is even difficult to secure correlations over short distances between Hudson and Schoharie valley ice margins. Rather than try to achieve a regional synthesis by using ice-front positions, our purpose here is to suggest relationships between high and low Mohawk discharges and lake stages, based on channel and terrace development and lacustrine stratigraphy.

STOP 1. Lake Albany 330-foot beach.
West of Bloominggrove Rd., one mile north of Defreestville, Troy South.
Reworked kame terrace gravels, berm, beach pond rhythmites.

STOP 2. Cohoes Falls.
Gorge of the Mohawk River is cut in folded Ordovician shale. Nickpoint marks post-Iroquois falls recession, about 2000 feet, from former point of upper gorge intersection with Fort Ann waters in the Hudson Valley. (Figure 11.)

STOP 3. Pit south of Lower New Town Rd.
In Lake Albany Halfmoon kame delta.
About 60 feet of section shows interbedded clinoform gravel and blue-gray flow till, fining upward to sand and silt-clay varves. Typical of south-facing ice-edge lacustrine deposits from which the ice recedes northward. See Figure 5.

STOP 4. Coveville 240-foot sand terrace
Coveville 240-foot sand terrace, inset in Albany clay, and fed by discharge through Round Lake channel into Lake Coveville at Mechanicville. See Figure 9.

STOP 5. Willow Glen kame delta; D.A.Collins pit.
About 100 feet of section shows black shale overlain by cemented gravel and sand and blue-gray boulder till, in turn covered by clinoform, locally deformed pebble gravel, sand, and Albany clay. Is the cemented gravel pre-Mohawk, or does the entire section show only a readvance into Lake Albany, followed by ice recession?

STOP 6. Coons Crossing.
Round Lake terraced channel with modern underfit Anthony Kill.

STOP 7. Bemis Heights clay pit.
About 55 feet of section exposes ice-contact Albany gravel and clay overlain by Quaker Springs clay and Coveville sand.

STOP 8. Reynolds pit.
Late Coveville 200-foot terrace is underlain by 5-15 feet of fluvial gravel with abundant Taconic lithologies derived from Hoosick basin. Flow sense is to the south. Beneath the Coveville gravel, 15 feet of Albany clay overlies 15 feet or more of ice-contact gravel and sand containing mainly Hudson valley lithologies.

STOP 9. Gullies eroded in distal end of Quaker Springs Hoosick delta
Gullies eroded in distal end of Quaker Springs Hoosick delta, later beheaded by Hoosic River dissection of delta.

STOP 10. Several Holocene terraces near modern stream
STOP 10. Several Holocene terraces near modern stream inside eroded Hoosic delta; road climbs eastward over older terraces related to drainage of Lakes Quaker Springs, Coveville and Fort Ann.

B7: STRATIGRAPHY AND DEPOSITIONAL HISTORY OF THE ONONDAGA LIMESTONE IN EASTERN NEW YORK
Richard H. Lindemann
R.P.I. and Skidmore College
The Onondaga Limestone is prominently exposed in hundreds of outcrops over a 550+ km. belt extending from Buffalo to the Helderberg and south to Port Jervis. The formation is a coarse- to fine-grained limestone, which ranges in thickness from 21.5 m. in the central New York type sections, to 49+ m. in the eastern and western parts of the state. The Onondaga Formation was deposited during Eifielian time (Middle Devonian) (Rickard, 1975), prior to and during the initial clastic influxes from the Acadian Orogeny. The unit represents the last extensive carbonate and reef-building phase in the region.
In modern times the stratigraphy, petrology, and bioherms of the formation have been extensively studied. Most investigations have neglected the formation's non-biohermal paleoecology, as well as its eastern sections. Whole formation studies have concentrated in western and central New York, and have extended typical characteristics to eastern areas. The purpose of this trip is to examine the lithologic and faunal characteristics of the Onondaga Formation in an area extending form the Helderbergs to Catskill, and to consider the paleoenvironmental conditions under which the unit developed.
No Stop Descriptions

B7: STRATIGRAPHY AND DEPOSITIONAL HISTORY OF THE ONONDAGA LIMESTONE IN EASTERN NEW YORK

STOP 1. See Figure 5

STOP 2. See Figure 5

STOP 3. See Figure 5

STOP 4. See figure 5

B11: FIELD GUIDE TO THE CHATHAM AND GREYLOCK SLICES OF THE TACONIC ALLOCHTHON IN WESTERN MASSACHUSETTS AND THEIR RELATIONSHIP TO THE HOOSAC-ROWE SEQUENCE
Nicholas M. Ratcliffe
U.S. Geological Survey
Reston, Virginia 32092
Since 1977, the U.S. Geological Survey has been engaged in a program to compile data for a new bedrock geologic map of Massachusetts. Don Potter and I have been mapping in northwestern Massachusetts in an attempt to fill in unmapped or poorly understood areas. Detailed mapping of the Pittsfield West, Hancock, Berlin, Williamstown, and parts of the North Adams and Cheshire quadrangles have been completed. This trip will deal principally with new data regarding the age, distribution, and structural characteristics of major boundaries at the soles of the Taconic allochthons (Fig. 1) exposed along the New York State line, and on Mount Greylock. An attempt will be made to relate these features to rocks exposed in the eugeoclinal Hoosac-Rowe belt east of the Berkshire massif. Time constraints for movement of these materials across the autochthon and the modes of emplacement will be discussed.

B11: FIELD GUIDE TO THE CHATHAM AND GREYLOCK SLICES OF THE TACONIC ALLOCHTHON IN WESTERN MASSACHUSETTS AND THEIR RELATIONSHIP TO THE HOOSAC-ROWE SEQUENCE

STOP 1. Contact between Taconic allochthon and autochthon.
Contact between rocks of Chatham Slice of Taconic allochthon and autochthon. Canaan 7-1/2 quadrangle.
Walk down the slopes to the east to the railroad tracks.
Caution! This railroad is operating and trains may come from either direction. There is enough room in the center island or along the rock walls, should a train arrive.
The geologic relationships at this stop are shown in Figures 7 and 8. The exposures in the tunnel are on the east flank of a doubly plunging anticline that produces a semi-window exposing unit g of the Stockbridge Formation. The allochthonous rocks of the Chatham slice consist of purple and green slate, green silty slate, massive beds of Rensselaer Graywacke, and basaltic volcanic rocks believed to be flows and tuffs.
The outcrops in the railroad cut expose the contact between the Chatham slice and the autochthon. A folded thrust contact (T1, Fig. 9) between overlying green phyllite of the Nassau Formation can be seen. Note the truncation of beds in the limestone by the contact. In addition, a fault sliver of green phyllite underlies an inverted sequence of Stockbridge and Walloomsac in a small anticline nearer the portal (thrust T2, Fig. 9).
Fault T1 traces out of the cut and forms the western limit of the allochthon. Fault T2 is not exposed again in recognizable form.
The relationship here suggests that the autochthon and allochthon were tectonically mixed during emplacement. In this model, rocks of the autochthon were overturned during thrusting and overridden by younger thrusts as illustrated below in Model 1 of Figure 9.
An alternative model involves recumbent folding of the thrust contact as shown in Model 2.

STOP 2. Basaltic volcanic rocks of the Chatham slice
Park at edge of large field before house. Walk east-northeast across field to slopes.
Basaltic volcanic rocks of the Chatham slice are well exposed on the slopes above the Boys Farm. This zone associated with graywacke has been traced continuously from the State Line quadrangle north to the Jiminy Peak area for a distance of 19 km. Similar occurrences are on the Knob across the valley to the west. This eastern belt of volcanic rocks is better laminated than those on the knob and at Fog Hill in the State Line quadrangle. The associated graywackes contain fragments of coarse-grained granite containing oligoclase and perthitic K feldspar.
The association of coarse, continentally derived clastic rocks with basaltic volcanics and probable fluviatile red beds suggests rift facies rocks similar to Triassic and Jurassic rocks of the Atlantic passive continental margin. These rocks are restricted Chatham and Rensselaer Plateau slices.

Outcrops of unit c of the Stockbridge.

STOP 3.Large roadcut of purple and green-phyllite.
Excellent roadcuts expose purple and green laminated phyllites of the next higher Taconic slice, the Perry Peak slice that is correlated with the Everett slice on Figure 1. Strong secondary slip cleavage and microfaults, accentuated by pods of bull quartz are common. The contact between the Chatham slice and the higher Perry Peak slice is a late thrust probably of Acadian age. From this contact zone eastward to the carbonate belt, a complex system of late thrust faults have been mapped in which slivers of carbonate, Walloomsac, and Taconic rocks are found. To the north, this thrust zone roots in the Precambrian (Proterozoic) rocks of Clarksburg Mountain.
Volcanic rocks and thick graywacke are not recognized in the higher Taconic slices. Is the absence of these rocks of stratigraphic significance, or are the volcanic rocks absent because of faulting? This is a serious problem that has not been resolved. Certainly the Greylock and Hoosac Mountain rocks are different stratigraphically than either the Chatham or Perry Peak rocks, as will be discussed at Stop 4.
From the roadcut, walk southwestward down to the old road and then follow the new wood road up the hill westward past green phyllite of the Perry Peak slice.
At 1550 ft elevation on bench a sliver of dolostone may be seen. The fault sliver occupies a position between the Perry Peak slice and Walloomsac of the autochthon below in a late fault.
This anticlinal belt of Walloomsac, however, underlies the Chatham slice rocks seen to the south at Stop 2.
From the carbonate rocks, walk northeastward down the slopes toward the brook, where inclusions of greenish-gray Taconic rocks may be found imbedded in the Walloomsac matrix.
This chaotic zone of wildflysch-like material evidently underlies the Chatham slice. Similar rocks are exposed to the south beneath the Chatham slice (Ratcliffe, Bird, and Bahrami, 1975, p. 82).
When the observations at Stop 1 and 3 are compared, the relations suggest that the Chatham slice was emplaced by a mechanism that involved recumbent folding, slivering of the autochthon, plucking of carbonate blocks signifying deformation of consolidated rocks. On the other hand, more ductile behavior with turbulent mixing of materials from autochthon and allochthon is necessary to account for the wildflysch-like breccias seen. A gravity induced spreading model to allow for creep in the autochthon may be the best explanation of these relationships. However, there is little evidence in favor of soft rock gravity sliding.

Side road leads to fossil locality
Side road leads to fossil locality in the basal part of the Walloomsac.

Rounds Rock.
Excellent cliffs west of road of green albitic Greylock Schist (optional stop).

STOP 4. Jones Nose.
Walk up the Meadow along the Appalachian Trail across limey albitic schist and schistose marble of the Walloomsac Formation here exposed by breaching of a refolded antiform that has a north dipping axial surface. This carbonate-rich unit is found at or near the base of the Walloomsac Formation regionally and on Mount Greylock, thus suggesting that older rocks are coming to the surface here. To the north, farther up the slope, a complementary, nearly recumbent syncline and anticline pair are exposed, also with north-dipping refolded axial surfaces. Section C-C' of Mount Greylock, Figure 3.

Greylock Schist / Walloomsac contact of autochthon
The bench the road follows is located on the contact between Greylock Schist and Walloomsac of the autochthon.

STOP 5. Stony Ledge.
Magnificant view to north and east into the Hopper. The ridge to the north is underlain by Greylock Schist, the valley by Walloomsac. To the east, the peak of Greylock and the steep west slope can be seen. Recent mapping suggests that there is double section of Greylock Schist exposed on Greylock with the axial surface of a large recumbent fold separating the mountain into lower limb and upper limb structures.
The Bellowspipe Limestone shown by Prindle and Knopf (1932) does not exist as a through going unit but is sporadically developed.
Excellent late crenulation cleavage can be seen in the ledges of green phyllite. These folds are post-metamorphic and correlate with the Green Mountain uplift folds or folds of F5 regional structures.

Core of the recumbent synform.
Climb road past dark albitic and green albitic schist of the lower limb into fine lustrous phyllites forming the core of the recumbent synform.

STOP 6. Excellent view all around, weather permitting.
Discussion of the regional geologic relationships.
At crest of Greylock, we are standing on chloritoid-rich phyllite in the axial part of a large westward topping syncline. Darker albitic phyllite, quartzite and graywacke form a rather continuous marker horizon that separates the more chloritoid-rich rocks from green and gray-white albite spotted granulites. Locally, this transition zone contains lenses of salmon pink dolostone in boudins, magnetite-rich schist, and gneissic pebble conglomerate. Albitic schists crowded with albite in massive exposures can be seen on the crest of Ragged Mountain to the north, on Cole Mountain to the south, Rounds Rock, Jones Nose, and on Mount Prospect to the west.
The structural interpretation of Mount Greylock shown in Figure 3 calls for a thrust sheet that has been recumbently folded. Plunges are to the north and south into the sections. In addition to recumbent folds that involve the thrust contact, internal structures are shown which are also recumbent but which are truncated by the thrust contacts. This suggests that rocks of the Greylock slice were folded prior to emplacement on the Stockbridge-Walloomsac sequence.
Relationship of the Greylock to the Hoosac Schist
The ridge seen to the east is the Hoosac Mountain underlain by Precambrian (Proterozoic) gneiss to the south and Hoosac Schist to the north. The carbonate valley narrows to the north in the North Adams gap where the Hoosac Mountain approaches the Green Mountains. A longitudinal sketch section is shown in Figure 11. It identifies two major thrusts on Hoosac Mountain: a lower thrust places Precambrian (Proterozoic) gneiss with its unconformable cover (Hoosac Schist and interfingering Dalton Formation) over carbonate rocks of the autochthon. This fault is essentially the fault mapped as "Hoosic thrust" by Herz (1961). A higher thrust places Hoosac with a more easterly facies above the western Hoosac belt. This fault is termed the Hoosac summit thrust. The eastern Hoosac sequence contains green albitic schist, dark albitic and garnet-bearing schist and light green chloritoid schist. This sequence resembles closely Greylock Schist units, although a greater development of albite-rich rocks is found on Hoosac Mountain than on Mount Greylock. Stratigraphic units defining recumbent metamorphic fold structures within the eastern Hoosac are truncated by the Hoosac summit thrust.
East of the Hoosac belt is the Rowe Schist, a pale-green, fine-grained chloritoid phyllite with interbedded dark carbonaceous phyllite and amphibolite all of presumed Cambrian through Ordovician age. Stanley has recently suggested (1978) that a major thrust fault (Whitcomb summit thrust) separates the Rowe from the Hoosac on the basis of recognized truncation of units in the footwall and hanging wall (see Fig. 5). The Rowe also contains abundant pods of ultramafic rock. This unit may mark the locus of crustal convergence in the Cambrian and Ordovician (Stanley, 1978).
On the basis on the stratigraphic similarities between the eastern Hoosac sequence and the Greylock section, and the lack of similarity of Greylock with western Hoosac, the root zone of the Greylock slice lies either in the eastern Hoosac belt or between belt and the Rowe.
The root zone of the Greylock slice lies east of exposed Precambrian (Proterozoic) of the Berkshire massif at this latitude. Because the Greylock slice shows the closest affinity to cover rocks of the massif, it seems clear that the lower slices of the allochthon were derived from more easterly sites.

Small crops of green chloritoid phyllite
Small crops of green chloritoid phyllite, with strong late fault fabric. Crops continue intermittently for 0.7 mile. Dark Walloomsac biotite grade phyllite is seen near north end of crops.

Large crop of Walloomsac.

Crop of Walloomsac (Owl)
Crop of Walloomsac (Owl) and isoclinal F1 folds.

Optional Stop: Cataclastically deformed phyllite
Stop at large crops of black Walloomsac 1.1 miles west. Cataclastically deformed phyllite can be seen faulted against green phyllite of the Nassau Formation. Characteristic plication of foliation, slickensides, and bull quartz pods mark a series of late faults in the Buxton Hill fault zone. This zone projects east of the late fault zone seen at Stop 3.

Crops of Stockbridge (OCsg) and Walloomsac (Ow)
Brodie Mountain ski area.

Large outcrops of sheared Walloomsac
Large outcrops of sheared Walloomsac in a late thrust zone.

STOP 7. Large road cuts in Stockbridge (OCsg).
Excellent recumbent folds can be seen, cross-folded by folds in N. 20° W. 22° NE dipping axial planes. The origin of the cross folds is not known but may be an expression of compression of a faulted sliver within the Buxton Hill fault zone.

Large crop of Stockbridge (OCsg) on east.
Large crop of Stockbridge (OCsg) on east. Thin zone 1 m thick of Walloomsac in a slickensided fault sliver is traceable for 75 m in this outcrop. This is an excellent example of character of the fault slivering within this late fault zone. 419 58.0 Large crops of fault slivered and cataclastic Walloomsac opposite the Mill on the Floss.
The valley to the north at South Williamstown to the east are highly fault intercalated zones of green albitic and non-albitic phyllite of the Greylock slice. To the west and north are green phyllites of Brody Mountain and Deer Hill. Exact placement of the boundary of the Greylock slice has not been possible. Allochthonous rocks on the northern end of Brody Mountain, however, are separated from the autochthon by a complexly intermixed zone of Walloomsac and green phyllite similar to the zone of mixed rocks seen below the Chatham slice at Stop 3, according to work by Don Potter. Because the Greylock slice does not have similar emplacement breccias and because the Greylock stratigraphy contains a greater abundance of albitic rocks than the Brody Mountain slice, the two slices are believed to be discretely different allochthons.

Large crops of fault slivered and cataclastic Walloomsac
The valley to the north at South Williamstown to the east are highly fault intercalated zones of green albitic and non-albitic phyllite of the Greylock slice. To the west and north are green phyllites of Brody Mountain and Deer Hill. Exact placement of the boundary of the Greylock slice has not been possible. Allochthonous rocks on the northern end of Brody Mountain, however, are separated from the autochthon by a complexly intermixed zone of Walloomsac and green phyllite similar to the zone of mixed rocks seen below the Chatham slice at Stop 3, according to work by Don Potter. Because the Greylock slice does not have similar emplacement breccias and because the Greylock stratigraphy contains a greater abundance of albitic rocks than the Brody Mountain slice, the two slices are believed to be discretely different allochthons.

Excellent view of Mount Greylock, the Hopper, Green Mountains
At crest of hill, excellent view of Mount Greylock and the Hopper, and the Green Mountains to the north. The broad carbonate valley extending from Williamstown east to North Adams consists of complexly folded rocks that appear to be detached from the Green Mountains by a major thrust fault that roots in the Hoosac Gap area. This fault slice, the Stone Hill slice, is named for exposure of the faulted rocks on Stone Hill south of Williamstown.

Stone Hill section
At dirt road, continue to north if permission to drive in is available. If not, we will walk in.
The Stone Hill section can be traced north to Buxton Hill where slivers of Stamford Granite Gneiss, Dalton and Cheshire thrust across units b and c of the Stockbridge in a complex thrust zone (see Stop 9).
The Stone Hill slice is believed to be a thin flap of autochthon originally rooted in the Adams or North Adams area that was thrust westward out of the North Adams gap area during an early deformation stage.
East-west trending hinge lines for early folds dominate the structure within the slice eastward to Mount Greylock where a late fault, the Clarksburg thrust, truncates structures in the slice.

STOP 8. Stone Hill slice.
One of the most complete stratigraphic sections of the Dalton Formation through unit C of the Stockbridge Formation is exposed in the area of Stone Hil l . Thin Cheshire Quartzite 10-0 m thick is interlayered with underlying black quartzose phyllite of the Dalton Formation. Dolostone of unit a of the Stockbridge overlies the Cheshire. Lithostratigraphic units of the Stockbridge here match closely rock section of the Vermont Valley sequence to the north.
The most anomalous features of the Stone Hill section are t he very thin Cheshire and the dissimilarity of this section to the Dalton-Cheshire section exposed on the Green Mountains to the north. Dark quartzose schists with a very thin quartzite is also a characteristic of the more easterly belt of Dalton and Cheshire mapped along the base of Hoosac Mountain and in the North Adams gap area.
Excellent recumbent folds can be seen in the cliffs above the road. The contact between the Cheshire and dolostone of unit a of the Stockbridge can be seen at the base of the quartzite cliffs to the north.

Crops to right are Chesire Quartzite.

STOP 9. Buxton Hill
Outlier of Stamford Granite Gneiss and blastomylonite and the sole of the Stone Hill slice.
The ridges to the south consist of blastomylonitic gneiss and Dalton with excellent recumbent fold thrust style. Syntectonic biotite from the blastomylonite yielded a K- Ar age of 387 ± 14 m.y. (394 ± 14 m.y. age calculated using new decay constant.) The biotite age is interpreted as a cooling age and a minimum for emplacement.
Crops around the north and east end of the hill are dolostone of the autochthon.

STOP 10. Hoosic thrust.
Herz (1961) drew the Hoosic thrust at the base of the exposures which he assigned to the Hoosac Formation. Reexamination indicates that these dark albitic, graphitic schists quartzites and limy schist should be assigned to the Walloomsac. Faulting is indicated by the shallow dipping spaced crenulation cleavage.
These exposures are on the north-plunging lower limb of a large recumbent syncline cored by Walloomsac that is refolded by north-trending late folds.
If time allows, we will drive into the quarry at natural bridge where an excellent recumbent anticline in unit e of the Stockbridge can be seen. This structure is on the lower limb of the major synclinal structure.
Those wishing to examine the excellent solution features in Mr. Elder's natural bridge, may do so for a slight fee. Those wishing to disband at this point, feel free to do so. Hard core elements may continue on to Hoosac Mountain!
2015: Mr. Elder's widow sold the tourist attraction to the state after he died in 1984, and it is now a state park.

Small crops of Dalton Formation
At the base of Hoosac Mountain are small crops of Dalton Formation interfingering with dark albitic schists of the western autochthonous Hoosac.

Green muscovitic chloritoid and garnet bearing schist of the eastern Hoosac
At the hairpin turn, green muscovitic chloritoid and garnet bearing schist of the eastern Hoosac may be seen. Excellent recumbent folds outlined by thin vitreous quartzite. This section is separated from the autochthonous Hoosac by the Hoosac summit thrust.

STOP 11. Top of Hoosac Mountain by observation tower
Excellent view back at Greylock, Taconic Range beyond, Green Mountains, and the North Adams Gap. Summary discussion of the relationships of the Hoosac-Greylock-Taconic belts and paleogeographic reconstructions.

B12: PRECAMBRIAN STRUCTURE AND STRATIGRAPHY OF THE SOUTHEASTERN ADIRONDACK UPLANDS
Brian Buddington Turner
Department of Chemistry
George Mason University
Fairfax, Virginia
The area of interest for this paper is the northern portion of the Bolton Landing quadrangle and adjacent parts of the North Creek and Paradox Lake quadrangles. Although there appear to have been at least five episodes of folding in the region, the southeastern Adirondacks appear to have undergone only four of the events (F1, F3, F4 and F5). F1 folds are large nappes. F3 folds range from isoclinal to tightly appressed similar folds in the study area. F4folds are moderately appressed similar folds, and F5 folds are relatively open similar folds. A large body of charnockite associated with F3 folding has the geometry of a nappe but was emplaced as a magma in advanced stages of crystallization. A structural dome of leucocratic granite was produced anatectically and solidified after F5 folding. Similar dome-like bodies of granite which do not show evidence of anatexis have fabric elements suggesting they were subjected to all four episodes of folding. The stratigraphic column of metasedimentary "formations" interspersed with "formations" of layered granite and quartzofeldspathic gneiss proposed by Walton (Walton and deWaard, 1963) is reinterpreted as recumbent synformal bodies of metasedimentary rocks separated by antiformal granitic nappes whose amplitudes are measured in tens of kilometers.

B12: PRECAMBRIAN STRUCTURE AND STRATIGRAPHY OF THE SOUTHEASTERN ADIRONDACK UPLANDS

STOP 1A. Alaskitic granites with some paragneiss
Outcrops on right (west) side of road are largely alaskitic granites with some strongly contorted layers of paragneiss. Although the outcrop is just outside the leader's field area, it was mapped at his suggestion by McConnell in 1964 and is deemed to be "basement". A two-meter exposure of an isoclinally refolded isoclinal fold is one of the main features of this stop. The first-formed fold has axial plane foliation and is believed to be an F1 fold. The second-formed fold deforms foliation and is believed to be an F3 fold. The other important feature of this exposure is the strong suggestion that the granite is an anatectic product of the paragneisses.

STOP 1B. Older Paragneiss
At the T-intersection with the Beaver Pond Road, an outcrop of Older Paragneiss (informal stratigraphic name) is located on the south side of the road. The outcrop contains a heterogeneous group of gneisses, quartzites and amphibolites. Of particular interest are the rotated (penetrative) clots of sillimanite and minor folds whose axes plunge about 20° in an azimuthal direction of 60°-65°, which is the local axis of F3 folding. This unit is believed to lie unconformably below the base of the supracrustal metasedimentary rocks, and in the opposite stratigraphic direction grades into granitic gneisses. A whole-rock, Rb-Sr age of 1210± 45 m.y. has been obtained from this outcrop.

STOP 2. - Brant Lake Gneiss
Brant Lake Gneiss (informal name) is exposed on the south side of the road. This rock is found throughout a structural dome to the south of the exposure. This granitic gneiss has a very uniform modal composition of approximately 35% quartz, 25% microcline, 30% sodic plagioclase, 3% mesoperthite, 5-7% biotite and 1% opaques. The granitic rocks of this dome yield a whole-rock, Rb-Sr age of 1119±39 m.y. It has been proposed that this granitic gneiss is an anatectic product of the Older Paragneiss (Bickford and Turner, 1971). This is a very brief stop.

OPTIONAL STOP
Older paragneiss in the road cut on the north side of Rt. 8 consists of quartzofeldspathic gneisses with accessory biotite and garnet. Most, if not all, minor isoclinal folds in this exposure show axial planar foliation. This paragneiss mantles the structural dome whose granitic core rock was observed at Stop #2, and may be traced almost continuously around the dome (see Plate 2 of accompanying description)

STOP 3. Simple set of folds.
In the road cut on the east side of the road is perhaps the simplest set of folds in the Swede Mountain structural complex. A large isoclinal synform is outlined by the contrast between quartzite and sillimanitic schists. Sillimanite needles just above the quartzite closure plunge about 5° in an azimuthal direction of 80°. Closer to the road, a minor fold crenulation plunges 20° in an azimuthal direction of 80°. The synform is thought to be an F3 fold. The isoclinal synform is clearly refolded. A stereographic beta diagram of attitudes of compositional layers shows an intersection which plunges 22° in an azimuthal direction of 116°, which comports with the axis of F4 folding. About 15 meters uphill along the road cut, a pair of refolded isoclinal folds about 3 meters long may be observed. Measurements of hinges and crenulations in these produce the same pair of data as for the large refolded synform.

STOP 4.- Pull into turn-out area on the right and park.
Walk back across Rt. 8 and continue east for about 50 meters. On the south side of the highway is a low road cut about 70 meters long. An isoclinal fold, whose limbs may be traced 55 meters to its closure, is exposed. Crenulations in the hinge plunge about 10° in the azimuthal direction of 103°. At least one minor isoclinal fold within the larger isocline displays axial plane foliation. This is probably an F1 fold. In the eastern part of the road cut, the limbs of the isocline have been refolded by an F4 fold. A beta diagram of the refold shows an axis plunging 30° in the azimuthal direction of 117° .
Returning to the western end of the road cut, and at about right angles to the cut, the outcrop portion of the exposure contains evidence of three episodes of folding (see Figures 1,2 and 3 of accompanying description). A complex F1 isocline has been isoclinally refolded into an F-? synform, and several smaller F4 folds have been superimposed on the refolded mass. Axial plane foliation in the F1 fold has been rotated by F?, and a weak F4 foliation with strong quartz rodding penetrates the outcrop. A beta diagram of compositional layers in the nose of the synform shows an intersection plunging about 5° in an azimuthal direction of 110°. This does not correspond with an F3 axis, and may represent an F2 refold. A beta diagram of the limbs of the refold shows an intersection plunging 15-20° in an azimuthal direction of about 120°, which corresponds with F4 fold axes. Although the beta maxima are only 10° apart in azimuth, the difference is believed to be real because measured hinge axes correspond with the 110° beta direction and measured quartz rods with the 120° beta direction.

STOP 5. Pull into turn-out area on left.
At this point the group may wish to split into two parties. Assuming that time permits, the leader will take a group of physically able participants on a 4-kilometer hike (total distance) to examine evidence of large nappe structure in Swede Mountain. Those persons not wishing to take the hike are invited to examine the 1.0 kilometer of nearly continuous exposure of Swede Mountain beside Rt. 8, which includes the structures seen at Stop #3.

STOP 6. (optional)
You are in the northeast quadrant of the North Creek 15' quadrangle, mapped by Geraghty (1973). The outcrops on the east side of the road are predominantly quartzofeldspathic schists and gneisses with abundant biotite, sillimanite and garnet (kinzigite) and quartzite. The author believes the kinzigite is an iron-rich facies of the basal khondalite seen in Swede Mountain. Some minor folds display axial plane foliation and may be F1 folds. Numerous axial traces of minor folds strike 60°-70° in azimuth, a biotite-sillimanite crenulation shows plunge of about 42° in an azimuthal direction of 59°, a beta diagram of one fold shows an intersection at plunge 26° in an azimuthal direction of 53°, and one minor fold hinge plunges 15° in an azimuthal direction of 70°. The foregoing reflect F3 folding. Several F4 cross folds are present and measured lineations and hinges have a range of plunges of 45° to 55° in azimuthal directions of 115° to 120°. At least one F5 fold is apparent in the outcrop, and its axial trace is about 10° in azimuthal direction.

B13: LATE WISCONSINAN - RECENT GEOLOGY OF THE LOWER RONDOUT VALLEY, ULSTER COUNTY, SOUTHEASTERN NEW YORK
Russell H. Waines
State University of New York College at New Paltz
Lower Rondout Creek extends eleven miles northeast from High Falls through Rosendale to the Hudson River at Kingston, New York. In this distance it drops from an elevation of about 120 feet at High Falls to sea level at Kingston. From High Falls to Rosendale the stream represents an easterly departure of the northeasterly-flowing Rondout Creek from its ancestral (preglacial) valley northwest of the Shawangunk Mountains. Maximum bedrock depths in the central Rondout Valley are considerably lower than the level of High Falls (Frimpter, 1970). A northeasterly retreating ice lobe in the central Rondout Valley with attendant preglacial impoundments and sedimentation at ever decreasing elevations controlled a final base level at about 400 feet.
At this point the ice lobe in the Wallkill Valley had begun to melt in such a way that the 400 foot level could not be maintained in the central Rondout Valley and base level was lowered to 250 feet or less. In the lower Wallkill (now lower Rondout) most sand deposits occur below 260 feet. The deflected Rondout now flowed into the northern (lower) portion of the ancestral Wallkill Valley bringing with it considerable sands and silts and some gravels as it cut headward in the central Rondout Valley cannibalizing preglacial sediments previously formed at higher elevations. The ultimate effect may have been the deposition of "wall-to-wall" sand in the lower Rondout Valley.
There is some question as to whether the interlaminated (varved) clays and silts of the lower Rondout Valley are contemporaneous in part with the sands which generally overlie them. The clay beds appear to have formed in front of ice, beside ice or under floating ice. The variation in elevation of the clay-sand contact, the absence of clay from some parts of the lower Rondout Valley and the general absence of interbedded clays, silts, and sands suggest the clays were formed before the sands and were even partly eroded before the sands were deposited. This would require considerable fluctuation of base level, largely controlled by the disposition of the ice lobe in the Hudson Valley, especially opposite Kingston.
In any event the sands seem to have been deposited under fluvial conditions with an ascending base level. The maximum elevation of 250 feet seems to have been controlled by spillage into the Hudson Valley through The Hell opposite Ulster Park (fig. 1). Soils maps suggest a dissected delta at the foot (east side) of The Hell.
After some evidence of a local glacier readvance over the sandplain at Maple Hill (Connally, 1968) and the development of possible small dunes at Tillson and Maple Hill the ice on the uplands on the north side of lower Rondout Creek appears to have stagnated. The ice lobe in the Hudson Valley seems to have withdrawn little by little, lowering base level in successive stages. In response to this, Rondout Creek seems to have begun headward erosion into sands and clays and eventually the production of paired and unpaired terraces at at least six different levels (Irving, 1972).

B13: LATE WISCONSINAN - RECENT GEOLOGY OF THE LOWER RONDOUT VALLEY, ULSTER COUNTY, SOUTHEASTERN NEW YORK

Bridge over Esopus Creek.

Esopus Creek and floodplain on right.

Divide between present day Esopus and Rondout
Divide between present day Esopus and Rondout drainage systems ca. 400 feet.

400 foot sandplain for next 0.4 miles
400 foot sandplain, somewhat dissected and possibly terraced for next 0.4 miles.

Road descends through cut in sandplain for 0.15 miles.

250 foot sandplain.

STOP 1. High Falls.
When blocked to the north while at a 400 foot base level Rondout Creek apparently found an outlet eastward into, under or around ice in the lower Wallkill drainage system. The river later established a base level at 250 ft. and subsequently has cut down to approximately 170 feet, the present level of bedrock (late Silurian Rondout Formation) at the top of the falls. The 250 foot sandplain can be seen to the north.

Village of High Falls
Delaware and Hudson Canal, Locks and Museum.

Approaching 210 foot sandplain terrace.

Rondout Creek on left.

STOP 2. Hurley Sand and Gravel Co., Inc. Sand and gravel pit.
This extensive pit has been developed in the 210 foot sandplain terrace. Remnants of the original 250 foot sandplain occur locally. Although stratigraphic exposures are poor, several large piles of coarse water-worn gravels remaining from sieving operations attest to the considerable gravel content of the sands. About 50 feet of gravels and sands fine downward to silts which in turn are underlain by clays. No where else in the lower Rondout Valley are gravels so abundant in the upper sands.

Till on hillside to left.

90 foot floodplain ahead.

Cross bridge over Rondout Creek. Village of
Rosendale.

Continue on sloping sandplain terrace ca. 100 foot level.

Descend to 50 foot floodplain and/or terrace.

STOP 3. Rondout Creek, Rosendale.
This floodplain and/or terrace was flooded in the summer and fall of 1955. Buildings on the north side of the river were flooded to the middle of their second stories. Part of the Army Corps of Engineers' stream channelization efforts in response to the 1955 floods can be observed.

Town of Rosendale Recreation Center on 70 foot terrace on right.
Ascend through sands to sandplain level.

250 foot sandplain for next 0.35 miles.
Village of Tillson.

Drive N up the gentle slope of the 250' sandplain.

Entering region of low sand hills on 250 foot sandplain.

STOP 4. Tillson sand hills.
Low sand hills rise 10 to 15 feet above the 250 foot sandplain along the southern margin of the Rondout Valley in the vicinity of Tillson. Inspection of a trench in the flank of one sand hill revealed a structureless non-stratified fine sand to silt. The hills are here thought to represent small sand dunes formed on the 250 foot sandplain just in advance of an ice front in the uplands on the north side of the Rondout Valley.

Turn right over sand hill onto Carroll St.

Swing right leaving sand hill area.

Sand hills to left (west) behind houses.

STOP 5. - Sand pit in 250 foot sandplain.
Almost the entire uppermost 110 feet of section is exposed with varying degrees of perfection. This is a shovel-stop. Sands fine downward into silts which overlie interlaminated (varved) clays and silts at about the 150 foot elevation. Extensive slump structures have been observed in the silts about 20 to 30 feet above the silt-clay interface. Gravels in the sands are fine and very infrequent. Current bedding, current and climbing ripples have been noted in the sands where bedding is generally thin to laminar.

Descend cut in sands.

50 foot terrace and sometime floodplain.
Modern floodplain at 40 feet along south side of Rondout Creek.

Flood control dike on right.

STOP 6. Maple Hill sand pit in 250 foot sandplain.
Here in an 80 foot sequence sands grade downward into silts which overlie interlaminated (varved) clays and silts at an elevation of about 160 feet. Little can be seen presently of the structure in the sands and silts. This pit was investigated as a potential sanitary landfill site but a high water table and water-saturated silts above the clays preclude its use for that purpose. A few low sand hills occur in the wooded area northeast of the pit. Of some interest is the till-like material overlying the sandplain near the pit entrance and elsewhere. Sieve analysis has yielded a polymodal distribution of particle sizes. This material is one line of evidence for the Rosendale Readvance of Connally (1968). Several samples of split-spoon core obtained in test-borings in the pit will be displayed.

STOP 7. Bloomington sandplain 190 foot terrace.
Local borings, some over 100 feet to bedrock, have encountered an almost total sand-silt sequence with little or no clay. Exposures of the upper sands may be seen in cuts southeast of the fire house.

190 foot sandplain terrace.

Lock of Delaware and Hudson Canal on left.

Large glacial clasts from "boulder train"
Large glacial clasts from "boulder train" crossing Rondout Creek on left. "Fines" have been removed from glacial till by the downcutting creek leaving clasts too large to move.

Delaware and Hudson Canal on left.

Small bridge over Greenkill Creek.
Rondout Creek and modern floodplain to right. Slightly higher floodplain terrace on far side of Rondout Creek.

50 foot terrace to right across Rondout Creek.

STOP 8. Sand pit. Do-it-yourself stop.
This pit is developed in the side of a typical sand-silt sequence rising to a 170 foot sandplain terrace. Ultimately about 130 feet of sands and silts are exposed and none of the typical interlaminated clays and silts have been encountered, even as low as the 40 foot elevation.

On the left, the ancestral Wallkill River probably passed.
On the right the Delaware and Hudson Canal descended through locks to tidewater.

STOP 9. New Salem sand pits.
The sequence on the hillside from the top down is as follows: The top sands occur 170 feet above the road or at about 260 feet elevation. The sands fine downward to silts for some 90 feet and red clays start about 80 feet above the road or about 170 feet above sea level. The sequence is somewhat similar to those of Stops 5 and 6 and unlike those of Stops 7 and 8.

Ancestral Wallkill River may pass under Show Boat on right.

STOP 10. City of Kingston sand and gravel pit.
Foreset beds of deltaic sands and gravels rest against steep bedrock surfaces. Sands and silts in attitudes of slump appear to have been deposited over ice. High up on the hillside to the northwest glacial striations are well-developed. Some of the foreset gravels are cemented to the hillside by means of calcium carbonate.

Gravel pit on left.

STOP 11. Sand pit. View stop.
This pit is developed in the lower portion of a sand-silt sequence rising to a 210 foot sandplain terrace to the northwest. The exposed sediments represent the bottom 160 feet or so of a 190 foot plus sequence. To the northwest sediments have been deposited against steep bed rock surfaces. Slumped sediments in the southwest corner of the pit may have been deposited over ice.

STOP 12. Twaalfskill Valley.
This narrow valley incised into Upper Silurian and Lower Devonian strata may represent an ancient drainage system from the north, possibly the ancestral Esopus. The bedrock profile in the center of the Twaalfskill Valley is not entirely known. This valley appears to have allowed passage of glacial waters and sharing of base level between the Esopus and lower Rondout Valleys. Sands at the 250 foot level extend through part of Kingston up the east side of the Esopus Valley.

STOP 13. View stop, 250 foot sandplain remnant.
From the road the confluence of the Hudson River and Rondout Creek can be viewed. Glacier ice in the Hudson Valley at this point influenced drainage and effective base level in the lower Rondout Valley. A second location about 50 paces southwest of the end of the road affords a view southwest up the lower Rondout Valley as far as Maple Hill. With skill various terrace levels and remnants of the 250 foot sandplain can be distinguished.

Field Studies of
New Jersey Geology
And Guide to Field Trips:
52nd Annual Meeting of the New York State Geological Association
Warren Manspeiser, Editor
Field trips are numbered as follows:
GEOLOGIC TRAVERSE:
GEORGE WASHINGTON BRIDGE TO THE DELAWARE WATER GAP
1.Triassic and Jurassic Formations of the Newark Basin
Paul E. Olsen
2. PreCambrian Rocks of the New Jersey Highlands
John H. Puffer
3. Lower Paleozoic Carbonates: Great Valley
Frank J. Markewicz and Richard Dalton
4. Geology of the Ridge and Valley Province, Northwestern New Jersey and Eastern Pennsylvania
Jack B. Epstein
FOLD BELT
5. Alleghanian Thrust Faults in the Kittatinny Valley, New Jersey
Avery A. Drake Jr. and Peter T. Lyttle
COASTAL PLAIN
6. The New Jersey Coastal Plain and its Relationship with the Baltimore Canyon Trough
Richard K. Olsson
7. Coastal Dynamics and Environments on Sandy Hook, New Jersey
Norbert P. Psuty, Lindsay Nakashima, and George Theokritoff
8. Landscape Features and Bog Iron Ore Deposits of the New Jersey Pine Barrens
Emily W.B. Russel and Edward Krug
GLACIATION
9. Late Wisconsin-Holocene History of the Lower Hudson Region: New Evidence from the Hackensack and Hudson River Valleys
Stephen. P. Averill, Richard R. Pardi, Walter S. Newman, and Robert J. Dineeli
ECONOMIC GEOLOGY
10. Economic Geology: New Jersey Highlands General Introduction and Road Log
Andreas H. Vassiliou
Uranium and Rare Earth Mineralization at the Bemco Mine Near Cranberry Lake, New Jersey
Iron Ore Deposits of the New Jersey Highlands
The Geologic Setting of the Sterling Hill Zinc-Iron-Manganese Deposit
Bob Metsger
ENVIRONMENTAL GEOLOGY
11. Environmental Geology: Hackensack Meadowlands
Sam L. Agron
12. Environmental Geologic Traverse.
Joseph A. Fischer
13. The Passaic River Flood Plain and Basin in New Jersey: Problems of Encroachment
Joseph S. Weisberg and John Marchisin
RIFT BASIN
14. Late Triassic Part of Newark Supergroup, Delaware River Section, West Central New Jersey
F.B. Van Houten
15. Brittle Faults (Ramapo Fault) and Phyllonitic Ductile Shear Zone in the Basement Rocks of the Ramapo Seismic Zone, New York
and New Jersey, and Their Relationship to Current Seismicity
Nicholas M. Ratcliffe
16. Rift Tectonics Inferred from Volcanic and Clastic Structures
Warren Manspeizer
17. Fossil Great Lakes of the Newark Supergroup in New Jersey

1: TRIASSIC AND JURASSIC FORMATIONS OF THE NEWARK BASIN
PAUL E. OLSEN
Bingham Laboratories, Department of Biology
Yale University, New Haven, Connecticut
Abstract
Newark Supergroup deposits of the Newark Basin (New York, New Jersey and Pennsylvania) are divided into nine formations called (from bottom up): Stockton Formation (maximum 1800 m); Lockatong Formation (maximum 1150 m); Passaic Formation (maximum 6000 m); Orange Mountain Basalt (maximum 200 m); Feltville Formation (maximum 600 m); Preakness Basalt (maximum + 300 m); Towaco Formation (maximum 340 m); Hook Mountain Basalt (maximum 110 m); and Boonton Formation (maximum + 500 m). Each formation is characterized by its own suite of rock types, the differences being especially obvious in the number, thickness, and nature of their gray and black sedimentary cycles (or lack thereof).
Fossils are abundant in the sedimentary formations of the Newark Basin and provide a means of correlating the sequence with other early Mesozoic areas. The Stockton, Lockatong, and most of the Passaic Formation are Late Triassic (?Middle and Late Carnian-Rhaetic) while the uppermost Passaic Formation (at least locally) and younger beds appear to be Early Jurassic (Hettangian and Sinemurian) in age. The distribution of kinds of fossils is intimately related to sequences of rock types in sedimentary cycles.
Far from being the consequence of the last gasps of the Appalachian Orogeny, Late Triassic and Early Jurassic Newark Supergroup basins formed in dynamic association with the opening of the Atlantic Ocean (Sanders, 1974; Van Houten 1977; Manspeizer, Puffer, and Cousminer, 1978; Olsen, 1978). In addition, Newark Supergroup rocks, once thought to be nearly barren of fossils, are now known to be exceptionally rich in organic remains (Thomson, 1979), replete with plants, invertebrates, and vertebrates spanning some 35 million years of the Early Mesozoic (Cornet, 1977). Finally, long episodes of unusually continuous deposition coupled with an abundance of laterally extensive stratigraphic "marker" beds (McLaughin, 1946), makes this deposit ideal for studying time-facies relationships and evolutionary phenomena. These recent discoveries have focused new interest on Newark strata.
The Newark Basin (Fig. 1 and 2) is the largest of the exposed divisions of the Newark Supergroup, covering about 7770 km2 and stretching 220 km along its long axis. The basin contains the thickest sedimentary sequence of any exposed Newark Supergroup basin and correspondingly covers the greatest continuous amount of time. Thus, the Newark Basin occupies a central position in the study of the Newark Supergroup as a whole.
In well over a century of study the strata of Newark Basin have received a relatively large amount of attention. By 1840, the basic map relations were worked out (Rogers, 1839, 1840, Cook, 1868) and by 1898, the major rock-stratigraphic subdivisions of the basin section were delimited and named (Darton, 1890; Kummel, 1897, 1898). Despite this long tradition, fundamental aspects of its historical and structural geology have remained essentially unexplored. The lithostratigraphy of the younger sediments, in particular, has received short shrift. Recently I have revised certain aspects of Newark Basin stratigraphy with an emphasis on the younger rocks (Olsen, in press). In the process I have proposed a number of new formational names (Table 2). Here I will review the formations of the Newark Basin and attempt to place their broader lithostratigraphic features into biostratigraphic context.

1: TRIASSIC AND JURASSIC FORMATIONS OF THE NEWARK BASIN

Begin Trip
To the east about one mile is the west portal of the George Washington Bridge, Fort Lee, New Jersey. The west abutments of the bridge rest on Stockton and Lockatong formations and Palisade Diabase. Roads along the east face of the Palisade Escarpment in the Fort Lee portion of Palisades Interstate Park have excellent exposures of nine individual detrital cycles of the lower Lockatong, each of which has been traced 15 km to the south (Olsen, this 1.7 Fieldbook). Three of these cycles are especially fossiliferous; the lowest of these (called cycle 6) has produced articulated remains of Semionotus brauni and disarticulated remains of the little reptile Tanytrochelos. The middle fossiliferous cycle (cycle 5) contains abundant disarticulated remains of Diplurus newarki and articulated remains of Turseodus. The upper cycle (cycle 2) has produced abundant articulated Turseodus and disarticulated large Diplurus. Clam shrimp (conchastracans) and ostracods are also common in cycles 5 and 2. These and other Lockatong cycles exposed here were deposited in shallower water than their more southern extensions.
In this area the trigonometrically computed thickness of both the Stockton Formation and the Lockatong Formation is less than 200 m. This is almost an order of magnitude thinner than the same formations along the Delaware River (Van Houten, this Fieldbook). While part of this thinning is due to the lateral replacement of Lockatong facies by Passaic Formation, most of the thinning is due to the thinning of individual cycles of the Lockatong Formation and thinning of the whole of the Stockton.
Numerous small, predominantly normal, faults striking north and northeast and down-dropping to the east characterize this portion of the Newark Basin. The reentrant in the Palisade Escarpment just south of here is an erosional result of some of the larger of these faults.

Cross large normal fault.
Crossing large normal fault cutting the Palisade Diabase and overlying the Lockatong Formation. This fault nearly doubles the outcrop width of the Palisade Diabase in this area. Just north of here the upper contact of the sill and the Lockatong is duplicated by this fault.
In marked contrast to faults is the northwestern portion of the Newark Basin, many of which have slickensides showing lateral (both sinistral and dextral) movement, those examined to date in the area along the Palisades show only vertical slickensides (both those dropping down to the east and to the west) (personal observation and Manspeizer, pers. comm.).

Lockatong-Palisade Sill contact
Excellent outcrops of the Lockatong-Palisade Sill contact and overlying detrital cycles of the Lockatong. Here the upper surface of the Palisade Sill is smoothly concordant with the Lockatong. I believe the cycles exposed here tie in with those exposed in Granton Quarry to the south, although it is far from certain. Articulated Turseodus and conchostracans, at least, are common at this outcrop.
According to Van Houten (1969), these Lockatong hornfels include grossularite-andradite, prehnite. and diopside varieties.

Stockton Formation
Hill at this point is underlain by a tongue of Stockton Formation (Van Houten, 1969). Presumably this is the same unit exposed about 1 km. north of Granton Quarry. There good exposures reveal Stockton Formation with a thin bed of Synorichthys -bearing green and gray siltstone with overlying beds of gray-buff arkose containing what I interpret as very well-developed limestone caliche paleosols. Tongues of Stockton such as this may correspond to clusters of chemical cycles prevalent in similar positions in the central Newark Basin.

Approximate contact with Passaic Formation.
Lowermost Passaic is very poorly exposed in the vicinity of Ridgefield and consists of mottled red-buff feldspathic sandstone and red siltstone.

Hackensack Meadows.
Broad belt of relatively soft red siltstone and minor gray siltstone and arkose correlating with upper Lockatong and lower Passaic Formation of Delaware River area (Van Houten, this Fieldbook).

Section A of Passaic type section begins here
Beginning of the type section of the Passaic Formation (see Table 2, fig. 4. this paper) (Olsen, In Press). The type section of the Passaic consists of intermittent exposures along Route 80. These exposures show interbedded red feldspathic sandstone and siltstone with small-to-large-scale cross-bedding, abundant bioturbation structures (including roots and Scoyenia) and some beds of caliche. Section A (fig. 4) of the type section begins here.
2011: Much of the outcrop has been obscured by sound barriers, probably constructed after 1980.

Section B of the type section of the Passaic Formation.
2011: Much of the outcrop has been obscured by sound barriers, probably constructed after 1980.

Section C of the type section of the Passaic Formation.

Section D of the type section of the Passaic Formation.

Garrett Mountain on Left, Passaic Falls on Right
Garrett Mountain is visible on left (south), Passaic Falls is on the right (north). The upper Passaic Formation of Rhaetic age (latest Triassic) has produced near here a series of well preserved skeletons of the highly specialized procolophonid reptile Hypsognathus (Colbert, 1946). About one skeleton or skull is found per decade.
Just south of this point, along Route 20 are exposures of Passaic Formation red conglomerates. The frequency of beds such as these increase to the northeast and decrease to the southwest. These conglomerate beds are crucial to tests of the "Broad Terrain Hypothesis" (Sanders, 1963, 1974). Cross beds consistently yield paleocurrent directions indicating transport from northeast to southwest (personal observation and Manspeizer, pers. comm.) in line with the mean paleocurrent vector for this portion of the Passaic Formation. Clasts consist primarily of Paleozoic sedimentary rocks, including quartzite, quartzite conglomerate, limestone, and minor phyllite. Such rocks are not known to be present to the east of the Newark Basin. Clast composition is very similar to beds found in the northernmost part of the Newark Basin, beds thought to have a northwestern provenance. The clasts are very different from those of the contemporary New Haven Arkose of the Hartford Basin. The "Broad Terrain
Hypothesis" predicts that these beds of the Passaic should be western equivalents of the New Haven Arkose. Two alternative explanations come to mind.
1. The provenance of these Passaic conglomerates was to the east of the Newark Basin; presumably these source rocks are completely eroded. Either the Newark and Hartford Basins were with the Paleozoic sedimentary rocks intervening or the Paleozoic rocks were exposed to the east of a southern continuation of the Hartford Basin and contributed to New Haven Arkose bed no longer exposed.
2. The provenance of these Passaic conglomerates was to the west or north but the sediments were redeposited by southwest moving streams.
Detailed studies of these conglomerates are clearly needed.

Contact of Passaic Formation with overlying Orange Mountain Basalt
Contact of Passaic Formation with overlying Orange Mountain Basalt on left (south). This is section E of the type section of the Passaic Formation (fig. 7). A series of faults cut the ridge made up of Orange Mountain Basalt here; some of these faults are visible in the cut on the left, just west of the Passaic-Orange Mountain contact.
Uppermost few meters of Passaic Formation, exposed to the south of here (Montclair State College) has produced a reptile footprint assemblage consisting of a mixture of taxa common to older beds of the Passaic and younger beds of the Feltville, Towaco, and Boonton Formations. The oldest North American occurrences of Batrachopus, and grullatorid footprints of the Anchisauripus minuscolus- type have been discovered at this locality (Olsen and Galton, 1977).
This assemblage is nearly identical to a suite of footprints found in the Rhaeto-Liassic of France. It is unclear whether these uppermost Passaic beds are latest Triassic or earliest Jurassic (the French workers are unsure of their footprint bearing beds, as well); The Triassic-Jurassic boundary probably lies within a few meters of the Orange Mountain in the Route 80 area.

Exposures of Orange Mountain Basalt.
Upper flow units of Orange Mountain Basalt are exposed in quarries near here. A diverse suite of zeolite minerals has made some of these quarries famous (Manspeizer, this Fieldbook; Van Houten, 1969).

Crossing the Passaic River
Crossing the Passaic River, which here follows the Feltville-Orange Mountain Basalt contact.
The Feltville Formation is very poorly exposed in this area; the lower Feltville is not exposed at all. Exposures in bluffs just north and south of here consist of gray and buff arkose and sandstone, often cross-bedded and containing coalified plant remains, and red feldspathic siltstone and sandstone with roots and reptile footprints.

Position of Preakness Basalt: not exposed.
A confluence of a series of faults, densely spaced joint systems, and the low dip of the bedding are probably responsible for the low profile of the Preakness Basalt in this area. The outcrops of the main lower flow in this area (such as along Route 46 to the south) show the flow's characteristic splintery joint pattern.

Approximate position of Preakness Basalt - Towaco Formation contact.
The large outcrop width of Towaco Formation here is due to the Hook Mountain Anticline. Toward the west, along the axis of the anticline, the dip of the Towaco Formation steadily decreases.

Reptile footprints to North
About 4.4 miles north is the abandoned Vreeland Quarry which produced the superb reptile footprints on display at the Rutgers University Geological Museum. Just to the northeast is Tom's Point, an area which produced hundreds of reptile footprints in the 1960's. Exposures still extant include much of the non-red portion of the second-from-the-top Towaco Formation cycle. Exposures of the upper two Towaco Formation cycles occur sporadically in surrounding areas.

Type section of Hook Mountain Basalt.
Two flows and the contact between them are exposed along the highway (fig. 11). The entablature and lower colonnade of the lower flow are exposed on Hook Mountain Road just north of the Route 80 overpass.

Approximate position of Boonton-Hook Mountain Basalt contact.

The Boonton Formation is not exposed along Route 80.
The Boonton Formation is not exposed along Route 80 but 2 miles to the north are the excellent exposures along the Rockaway River (fig. 12). These exposures begin at the dam at the north end of Boonton (Jersey City) Reservoir and extend for over 1 mile along the river bluffs. The dam footing rests on the Boonton Fish Bed which during the 1800's and early 1900's produced thousands of fish of the "Semionotus elegans group," Redfieldius spp., several specimens of the large coelacanth Diplurus longicaudadus, and a single specimen of Ptycholepis.
Only the underlying beds are exposed now, by these beds produce abundant plant remains and reptile footprints.

Approximate position of the Ramapo Fault: end of the Newark Basin.
A prominent bluff of metamorphics marks the west wall of the fault (see Ratcliffe, this Fieldbook).

2: PRECAMBRIAN ROCKS OF THE
NEW JERSEY HIGHLANDS
JOHN H. PUFFER
Rutgers University Newark, New Jersey
Rocks exposed along Route 15 offer an excellent opportunity to observe most of the major metamorphic and igneous units that make up the New Jersey Highlands (Fig. 1). Rock is exposed along almost the entire twenty kilometers of Route 15 that traverse the strike of the rock units. The purpose of this field guide is to describe the rock units exposed along Route 15 and to report on the current status of recent efforts aimed at understanding the metamorphic and igneous environments that formed the rocks,
Most early descriptions of the New Jersey Highlands subdivide the Precambrian into four major units: These four units appear on the legend of Lewis and Kummel's (1910-1912) Geologic Map of New Jersey as:
1. Byram Gneiss "Gray granitoid gneiss composed of microcline, micro-perthite, quartz, hornblende or pyroxene, and sometimes mica".
2. Losee Gneiss "White granitoid gneiss composed of oligoclase, quartz, and occasionally orthoclase, pyroxene, hornblende, and biotite".
3. Pochuck Gneiss "Dark granular gneiss composed of pyroxene, hornblende, oligoclase, and magnetite".
4. Franklin Limestone "Coarse white marble..."
More recent works by Hotz (1952), Sims (1958), Drake (1969), Smith. (1969), and Baker and Buddington (1970) have subdivided the Byram Gneiss into a "Hornblende Granite" and a "Pyroxene Granite" and a few minor units; have substituted rock names such as "Quartz-Oligoclase Gneiss" and. "Hypersthene-Quartz-Oligoclase Gneiss" for portions of the Losee Gneiss; have subdivided the Pochuck Gneiss into "Amphibolite" and "Pyroxene Gneiss"; and have recognized several additional rock units such as "Quartz-Potassium Feldspar Gneiss and "Syenite Gneiss". Widmer (1964) has recognized twenty-four mappable Precambrian rock units in the New Jersey Highlands including marble, quartzite, skarn, pegmatite, quartz diorite, four kinds of granite, and fifteen kinds of gneiss. Because of the general reconnaissance nature of this field trip only the major units among the complex assortment of Highlands rock types will be described in this report.

2: PRECAMBRIAN ROCKS OF THE
NEW JERSEY HIGHLANDS

STOP 1. Hornblende Granite (sample 0.9, Table 3).
Exit at the Picatinny Arsenal. The rock exposed along the hill to the right is Hornblende Granite. Exercise extreme caution when crossing the road to examine the granite. The granite here is quite homogeneous but on the other side of the hill contains less hornblende and becomes an alaskite. Note the well developed foliation.

Green Pond Fault.

Green Pond Conglomerate
Green Pond Conglomerate; silurian correlative of Shawangunk Conglomerate. Most of the pebbles are rounded milky quartz.

Very complex mixture of Pyroxene Granite
Very complex mixture of Pyroxene Granite near the south
end of the roadcut (sample 3.6, Table 3). Quartz-Oligoclase Gneiss near the center, and Hornblende Granite near the north end (4.0 mile on log). Several disconnected xenoliths of amphibolite may be observed in the granite as well as numerous granite pegmatites emplaced parallel to the foliation of the granite.

Amphibolite (sample 4.3, Table 3).

Fine grained quartz monzonite alaskite and Amphibolite
Fine grained quartz monzonite alaskite along end of roadcut; Amphibolite along the north end.

Pyroxene Granite (sample 5.9, Table 3).

STOP 2. Pyroxene Granite.
Note the wide ranging quartz content, dark color, and well developed foliation. The pyroxene component of the rock here is deeply altered; the feldspar component ranges from a plagioclase rich perthite (as in sample 5.9, Table 3) to a K-spar rich antiperthite (as in sample 6.6, Table 3). Busses will park on breakdown lane. Watch out for loose rock on vertical face of road cut.

Pyroxene Gneiss
Pyroxene Gneiss composed of approximately 50 percent antiperthite, 10 percent plagioclase, 15 percent quartz, 20 percent pyroxene-amphibole intergrowths, and 5 percent opaque oxides.

Pyroxene Granite

Pyroxene Syenite (sample 8.2, Table 3).

Pyroxene Granite
Pyroxene Granite including bands of syenite and various gneisses that have a similar general appearance but dissimilar mineralogies making up a virtually unmappable complex for 0.3 mile. Amphibolite bands are also found here.

STOP 3. Syenite Gneiss (sample 8.7, Table 3).

STOP 4. Quartz-Oligoclase Gneiss, (samples 9.1a and b, Table 3).
STOP 4. Quartz-Oligoclase Gneiss, (samples 9.1a and b, Table 3). Both white and pink varieties of Quartz-Oligoclase Gneiss occur here. Most of the rock here contains less biotite and is less foliated and banded than more typical Quartz-Oligoclase Gneiss. Amphibolite schliern are common. Busses park on abandoned entrance road to Route 15.

Amphibolite.

Quartz-Oligoclase Gneiss

Amphibolite

Hornblende Granite.
Hornblende Granite. Alternating plagioclase rich and
K-spar rich bands make this rock less homogeneous than
the granite at STOP 1.

Kittatinny Limestone. Cambro-Ordovician dolomitic limestone.

Hornblende Granite

Granodiorite Gneiss.
Highly foliated rock composed of 40 percent plagioclase, 30 percent quartz, 20 percent K-Spar, and 10 percent biotite.

STOP S. Franklin Marble.
The marble is intruded by granite pegmatites. If traffic is heavy it may be necessary to skip this stop. The road shoulder is quite narrow.

3: LOWER PALEOZOIC CARBONATES:
GREAT VALLEY
Frank J. Markewicz and Richard Dalton
New Jersey Department of Environmental Protection
Division of Water Resources, Trenton, New Jersey
The purpose of this field trip is to demonstrate the subdivision of the Cambro-Ordovician carbonate sequence as proposed by the field trip leaders. In addition, there will be discussions on environmental, hydrogeologic, and engineering problems in these carbonates and how this subdivision has "opened the doors" in understanding how everyday problems from man's activities can affect or be affected by certain lithic units within the carbonate sequence. This understanding of the interaction between man's activities and how it might affect or be affected by critical aquifers, thin or thick soil horizons, and specific lithologies by septic waste loads, ground water pollution, building foundation loading, landfills, etc., has become extremely important in the land development process.
We anticipate this field trip will not only relate the carbonate subdivision but will point out how important this breakdown is to applied geology.

3: LOWER PALEOZOIC CARBONATES:
GREAT VALLEY

STOP 1. Limeport member of the Allentown Formation.
Geologic Setting
Although less than 20 feet is exposed here it contains many of the sedimentary features found in the member.
In the Pequest Valley the highest stratigraphic rocks found by Markewicz and Dalton include units from Leithsville through the middle part of the Upper Allentown. Stop 1 is considered to be in the lower half of the Limeport Member.
The southeastern edge of the valley is underlain by a normal section of "Kittatinny" sediments lying above the Precambrian.
Along the southwestern border of the valley there are complex structural relationships just before the point where Route 80 enters the Jenny Jump Mountain Precambrian units. There have been various interpretations for this contact between the Precambrian and Paleozoic. These include nappe theories, normal contacts, and various fault interpretations such as an unrooted thrust block.
The Leithsville and Lower Allentown (Limeport) typically form a topographic lowland on the eastern border of the valleys in northern New Jersey. Leithsville rocks generally underlie the lowlands or river valleys and have a greater thickness of unconsolidated sediments -sand, gravel, clay, etc. overlying bedrock than any of the other formations of the "Kittatinny group." The Limeport, typically more resistant than the Leithsville forms a slightly higher pronounced bench. It is generally overlain by overburden that is thinner than the underlying Leithsville overburden, but thicker than overburden Upper Allentown.
Geologic Features
(a) algal units
(b) oolitic and local pisolitic units
(c) churned, lumpy, patchy bioturbidite facies
(d) intraformational conglomerate facies
(e) sandy facies
(f) ruditic, patchy textured clast conglomerate
(g) various dolomite facies, from dolomitic mudstones to medium coarse crystalline dolomite grainstone.
Many varied shallow water carbonate environments can be found at this stop. This is the type of outcrop that a geology professor likes to take his students to so that they can observe the many features that they hear about in the classroom.

Diabase dike within metasedimentary calc-silicates and various gneisses.

STOP 2. Harmonyvale Member of the Ontelaunee Formation
Geologic Setting
This is the first exposure of dolomite on the west side of Jenny Jump Mountain.
During the construction of Rt. 80 the Jacksonburg Limestone was exposed at the east end of the exposure. On the west side of Jenny Jump, the first rock exposed is always the Jacksonburg along with the uppermost part of the Kittatinny sequence.
At Stop 2 exposures of the uppermost-lower Ordovician dolomite present in New Jersey can be observed; this is the Harmonyvale member of the Ontelaunee Formation.
Geologic, Features
(a) dark to black wispy lines or streaks
(b) medium crystalline fetid beds
(c) massive paleo-solution breccia with silt (paleokarst feature)
(d) possible fossils
(e) recent karst features
Black wispy lines are an important feature to be noted here. These seem to have been formed through some deformation process shortly after deposition of the dolomite since the Jacksonburg conglomerates in this region contain dolomite cobbles which have the wispy lines.

Exposures of the upper part of the Allentown Formation

STOP 3. The Rickenbach and Epler Formations
This series of exposures which starts in the upper Allentown Formation and extends up to the Lafayette Member of the Epler forms one of the most complete sections in this area. Off the road, the section continues up into the Jacksonburg Limestone. We will be limiting discussion to the Rickenbach and Epler Formations at this stop.
A. The Rickenbach Formation at this locality measures approximately 290 feet and both the lower and the Hope Members are present. This stop is also the type section for the Hope Member. The features to note are:
a) compare lithologies of the lower member with the Hope Member. .
b) clots of black botryoidal hydrocarbon? material -anthrazalite?
c) sand in the dark aphanitic beds
d) the "7 cherts" horizon
e) the upper chert horizon
f) algal structures
g) Trace amounts of sphalerite occur over a stratigraphic thickness of 225 feet.
B. The Epler at this stop has complete sections of the Branchville and Big Springs Members and a partial section of Lafayette Member. The features to note in the Epler are:
a) compare the alternating medium to massive bedded sequence of the Hope Member of the Rickenbach with very massive bedded laminated dolomites of the Branchville Member of the Epler.
b) the similarity Member of the Branchville with the Lafayette
c) note the siliceous ribbing (interbeds) as well as distinctive reddish weathering characteristic of dolomite.
d) the paleo-solution breccia in the Lafayette Member
e) fossils found in the Big Springs Member.

STOP 4. Rickenbach Formation
From Stop 3 the highway cuts across the Jacksonburg and the Martinsburg Formations west of Route 521. As the highway ascends the large hill known as Mt. Herman a west dipping thrust fault is crossed. The first dolomite exposure is the Limeport Member of the Allentown Formation.
The west side of Mt. Herman is also bounded by a fault. This fault, based upon preliminary mapping is high angle.
Geologic Features
a) the changes in dip
b) the large amount of sulphides present in the rock

4: GEOLOGY OF THE RIDGE AND VALLEY PROVINCE, NORTHWESTERN NEW JERSEY AND EASTERN PENNSYLVANIA
JACK B. EPSTEIN
U. S. Geological Survey
Reston, Va. 22092
The rocks seen in this segment of the field trip range in age from Middle Ordovician to Middle Devonian and constitute a deep basin-continental-shallow shelf succession. Within this succession, three lithotectonic units, or sequences of rock that were deformed semi-independently of each other, have somewhat different structural characteristics. Both the Alleghenian and Taconic orogenies have left their imprint on the rocks. Wind and water gaps are structurally controlled, thus placing doubt upon the hypothesis of regional super-position. Wisconsinan deposits and erosion effects are common. We will examine these geologic features as well as some of the economic deposits in the area.
Figure 1 is an index map of the field-trip area, showing the trip route and quadrangle coverage. Figure 2 is a generalized geologic map,

4: GEOLOGY OF THE RIDGE AND VALLEY PROVINCE, NORTHWESTERN NEW JERSEY AND EASTERN PENNSYLVANIA

Allentown Dolomite in the Hope klippe
Gently dipping Allentown Dolomite in the Hope klippe (see Drake and Lyttle, this volume).

Dolomite and cherty dolomite in the Allentown (?) Dolomite.

Small anticline in the Allentown (?) Dolomite.

Graywacke and slate in the Ramseyburg Member, Martinsburg Fm
Graywacke and slate in the Ramseyburg Member of the Martinsburg Formation. We have just crossed a major fault separating the Middle and Upper Ordovician Martinsburg from Cambrian carbonate rocks in the Hope klippe. <br

Kittatinny Mountain to the right
Kittatinny Mountain to the right (north) held up by quartzites in the Silurian Shawangunk Formation. The mountain is offset to the northeast by a syncline-anticline couplet near the site of the Yards Creek Pumped Storage Project north of Blairstown, N.J.

STOP 1. Discussion Of Trip And Lunch.
See Fig. 4 for stop description. After leaving Stop 1, we will travel down the Paulins Kill Valley, across the Delaware River, travel to the southwest to Pen Argyl, Pa., and stop at a slate quarry in the upper (Pen Argyl) member of the Martinsburg Formation. After crossing Blue Mountain at Wind Gap, we will visit a quarry at Bossardsville. Pa., in Silurian rocks. We will than attempt to drive to the top of Kittatinny Mountain to a vantage point overlooking Delaware Water Gap and examine the Shawangunk Formation and Bloomsburg Red Beds. After passing through the gap we will return to Newark, N.J.

Laminated slates of the Bushkill Member, Martinsburg Fm
Laminated slates of the Bushkill Member of the Martinsburg Formation. Note the typical fine bedding in this member. You will not see similar laminations in slate of its Pen Argyl Member. This is one of the characteristics distinguishing the two predominantly slate-bearing members of the tripartite Martinsburg Formation.

Paulins Kill to right.

Southeast-dipping dolomite of the Epler Formation.
We have crossed the Portland fault which separates the Epler from the Bushkill Member of the Martinsburg Formation.

Crossing Delaware River.
View of Delaware Water Gap to right (north). Tuscarora Power Plant smokestacks to left.

Toll Booth.
Continue straight ahead on U.S. 611S. We will be driving on the Richenbach Dolomite of the Beekmantown Group for about O.5 mile (0.8 km) and then on Wisconsinan kame deposits and till.

View of Kittatinny Mountain to right.

Wisconsinan sand and gravel and some till
The lowlands to the right are mostly underlain by Wisconsinan sand and gravel and some till.

Five Points. Thick glacial deposits
Glacial deposits are as much as 178 feet (54 m) thick in this area.

Graywacke and slates of the Ramseyburg Member, Martinsburg Fm
Crest of hill underlain by graywacke and slates of the Ramseyburg Member of the Martinsburg Formation. Note slate dumps ahead.

Slate dumps of the abandoned Capitol Slate quarry on right.
Slate dumps of the abandoned Capitol Slate quarry on right. Note the much thicker beds than in the Bushkill Member of the Martinsburg seen at mileage 7.4. We are in a slate "run" in the upper part of its Ramseyburg Member. Graywackes are found higher in the sequence and the contact with its overlying Pen Argyl Member is placed where graywacke beds become less dominant.

Flooded New Bangor and Columbia Bangor quarries on left
Flooded New Bangor and Columbia Bangor quarries on left, with nearly recumbent folds.

The Bangor Excelsior quarry on the left has been filled in
The Bangor Excelsior quarry on the left has been filled in, partly with fly ash. It was at least 140 (43 m) feet deep.

Pennsylvania Historical and Museum Commission sign
Pennsylvania Historical and Museum Commission sign on right: "Slate Industry - Robert M. Jones of Wales, who U.S. came here in 1848 as an immigrant, began the slate quarrying industry. The region became a major world center for slate. From here came slate roofs and old-time school slates and pencils."
To the right of the sign are the remains of an old kiln that used to fire the slate for lightweight aggregate (see Epstein, 1974a, for a discussion of the slate industry and potential uses for waste slate).

The Old Bangor slate quarry is over the dumps to the left.
The nearly flat Old Bangor syncline is exposed in the quarry and can be traced for several miles in the area. The quarry also lends its name to the "Old Bangor run", a series of beds that include important commercial slate beds.

Crest of Wisconsinan terminal moraine.
Poor exposures of till may be seen in cuts to the right.

Wisconsinan till to east and Illinoian(?) till to west.
Contact between the Wisconsinan till to east and Illinoian(?) till to west. Note slate dumps from quarry in the Pen Argyl Member of the Martinsburg Formation straight ahead.

STOP 2. Stephans Jackson Slate Quarry
Stephans Jackson Slate Quarry; Structure And Stratigraphy Of The Martinsburg Formation; Slaty Cleavage; Quarrying Operation.
DANGER-STEEP QUARRY WALLS, DO NOT BE TOO BOLD!
The Stephans Jackson Slate Quarry is one of only a few that remain active in the slate belt of Pennsylvania which extends for about 45 miles (72 km) west of the Delaware River. The belt is dotted with more than 400 abandoned slate quarries and prospects. The quarry is currently about 350 feet (110 m) deep. Quarrying and milling methods have changed little for the last 50 years, and are still much the same as described by Behre (1933). The slate is used for roofing, blackboards, flagging, aquaria bottoms, sills and treads, and billiard table tops. Immediately southwest over the dumps is the abandoned Parsons quarry. which reportedly was more than 900 feet (274 m) deep, the deepest slate quarry in the United States.
The Stephans Jackson Slate Quarry is in an overturned syncline whose axial plane dips gently to the southeast (fig. 5). A bedding-slip fault forms much of the northwest wall of the quarry. Slaty cleavage and bedding in the overriding block are dragged into the fault and a slip cleavage that shows antithetic movement to the fault, has developed in the drag fold (see inset, fig. 5). In general, slaty cleavage forms a gentle arch and fans the fold by about 14°. The fault is marked by a gouge or "spar zone" that is as much as 2 feet thick and filled with quartz and calcite.
The fault zone is a marked zone of weakness in the rock. In 1948, the northeast section of the quarry was being worked when a large mass of rock slipped down into the quarry along the zone, killing two workers below. That part of the quarry was abandoned, and the presently active section was started. Note the pins that were bent by the sliding mass in the northern corner.
The sequence of deformation was complex. Bedding-plane slickensides that are offset by cleavage indicate that initial flexural-slip folding was followed by passive folding (fig. 46, Epstein and Epstein, 1969). As the folds continued to tighten, failure was again along bedding, producing the bedding-slip fault, warping of slaty cleavage, and formation of crenulation cleavage parallel to the axial plane of the cleavage fold. Movement along the bedding-slip fault was up to the northwest, as indicated by the drag, but steps on one of two slickensided surfaces in the fault zone indicate an opposite sense of movement, perhaps due to earlier flexural slip.
The origin of slaty cleavage in the Martinsburg Formation, as well as in rocks above and below, has been a focus of considerable attention during the last two decades. Did it form by tectonic dewatering or did it form under conditions of low-grade metamorphism? Mapped relationships and petrologic considerations led me to conclude that it formed as a product of metamorphism (Epstein, 1974b) by a combination of the following processes: mechanical rotation of detrital grains parallel to the cleavage, corrosion of quartz by pressure solution and migration of silica. intrusion and flow of pelitic material, grain diminution by granulation, and by recrystallization and neocrystallization.
The Stephans Jackson Slate Quarry is in the Pen Argyl Member (upper) of the Martinsburg Formation and is about 1500 feet (457 m) above the contact with its Ramseyburg Member (middle) (fig. 6). The Pen Argyl is typically thick bedded, containing some beds of gray slate more than 10 feet (3 m) thick. The member is cyclically bedded, each cycle consisting of medium-gray slate grading up into grayish-black carbonaceous slate. Graywacke may form the base of some of the cycles.
For more than 70 years there has been controversy regarding the number of members in the Martinsburg (see Drake and Epstein, 1967). On the basis of the very characteristic difference in bedding thickness between the lower (Bushkill) and upper (Pen Argyl) members, and as proved by detailed mapping (fig. 6), I have mapped three members in this area, nearly in the same manner as Behre (1933). The Pen Argyl cannot be the Bushkill repeated by folding as earlier suggested by Stose (1930), for example. Recently, Stephens and others (1979) argued for a two-fold division based on fossil collections in the Schoharie "Ridge' area, about 35 miles (56 km) to the southwest. This bipartite interpretation, however, is presently clouded by structural complications that may be present in that area (Epstein and others, 1972; Lyttle, 1979).

Gentle slopes underlain by colluvium and Illinoian(?) till
We will be riding on gentle slopes underlain by colluvium and Illinoian(?) till which cover the Pen Argyl Member of the Martinsburg. Quartzites in the Shawangunk Formation are seen in cliffs in Blue Mountain to the right.

The low col straight ahead is Wind Gap
Exposures of the lower (Minsi) member of the Shawangunk Formation in woods on left. The low col straight ahead is Wind Gap, underlain by nearly vertical quartzites and veneered with weathered colluvium.

Red shale, siltstone, and sandstone of the Bloomsburg Red Beds.
For about 1.5 miles (2.4 km) along Pa. 33, the Bloomsburg is thrown into many small folds that are superimposed on the Ross Common Creek syncline and Wind Gap anticline. Note the well-developed cleavage in the Bloomsburg.

Chestnut Ridge to the left
Chestnut Ridge to the left, underlain by complexly folded rocks of Late Silurian and Early Devonian age.

Bloomsburg Red Beds to right.
Cherry Ridge straight ahead held up by sandstones in the Ridgeley and Palmerton Sandstones.

Wisconsinan till in road cut to right.

Cut through Cherry Ridge
Cut through Cherry Ridge in South-dipping overturned Esopus and Schoharie Formations and Palmerton Sandstones.

Many abandoned clay pits
Many abandoned clay pits in deeply weathered Buttermilk Falls Limestone are in woods to right. These are in saprolites as much as 250 feet (76 m) deep. The clay is used as whitener in cement.

Panoramic view to left (see fig. 7).

Hill to right underlain by Decker Formation and Bossardville Limestone.

STOP 3. Hamilton Stone Company Quarry.
Stratigraphy And Structure Of Upper Silurian Rocks In Cherry Ridge.
Three Upper Silurian units are well exposed in the quarry in a series of upright to tight and slightly overturned folds (fig. 8). The units are, from top to bottom:
Wallpack Center Member of the Decker Formation:
Medium-bedded and lenticular medium.gray to medium-light-gray, fine-to coarse-grained, quartzose limestone, medium-gray, fine-to coarse-grained calcareous sandstone, siltstone, and conglomeratic sandstone, containing brachiopods, rugose and colonial corals, bryozoans, and crinoid columnals. Leperditiid ostracodes are abundant near basal mud-cracked dolomite. Upper contact concealed. About 70 feet (21 m) exposed. Forms cap rock. Useful for crushed stone.
Bossardville Limestone:
Graded laminated to very thin-bedded, dark-gray, fine-to very fine grained pyritic argillaceous mud-cracked limestone with scour-and-fill at base of graded units and leperditiid ostracodes. Uppermost beds very finely laminated limestone and smaller amounts of dolomite. About 95 feet (29 m) thick. Quarry rock useful for crushed stone.
Poxono Island Formation:
Interbedded and interlaminated medium-gray, calcareous dolomite, medium-gray and mottled pinkish-gray-green to medium-greenish-gray to gray, very fine grained dolomite, grayish-red limestone, and light-grayish-yellow-green shale and calcareous shale; contains several mud-crack intervals. Uppermost dolomite contains color contortions. About 40 feet (12 m) exposed.
These rocks are interpreted to have been deposited in a complex and generally transgressive tidal-flat barrier-bar shallow subtidal environment on the basis of lithology, sedimentary structures, texture, bedding characteristics, fossils, and lateral facies (see Epstein and others, 1967, and Epstein and Epstein, 1969, p. 192-196).
The structure in the quarry area is dominated by about 25 folds whose axial planes strike N. 50° - 60° E. and whose axes plunge about 5°SW. These folds are disharmonic on the Kemmererville anticline in the Bloomsburg Red Beds in the underlying lithotectonic unit. The Poxono Island Formation is believed to be separated from the Bloomsburg by a decollement (see cross section, fig. 8). The anticlinal ridge underlain by the Bloomsburg rises as we travel to the northeast after leaving the quarry.
Folding was initiated by flexural slip followed by passive folding and development of cleavage. This is indicated by cleavage that wrinkles bedding-plane slickensides. In a few places, such as in the 10 foot-(3 m) wide fault zone in the east corner of the quarry, a slip cleavage cuts the earlier cleavage.
The stratigraphic units behaved differently during deformation. The more pelitic rocks failed passively, with development of prominent cleavage, whereas the more competent carbonate rocks and sandstones in the Decker and the Bossardville were concentrically folded and in places formed fold mullions. This small-scale folding is somewhat disharmonic and folds in the Poxono Island are generally tighter than in overlying rocks. This disharmonic folding is similar to the structure on a regional scale.
Places that we may visit in the quarry depend on the whims of the shovel, but we will probably go to three localities shown in figure 8: (A) A very tight anticline in the Poxono Island Formation and a fault that cuts out about 50 feet (15 m) of the Bossardville Limestone are conspicuous in outcrop here (fig. 9). As we look to the west from a high point we can see the Trimmers Rock and Catskill Formations in the southwest-plunging Weir Mountain syncline. To the north, the Pocono Plateau, Godfrey Ridge, and glacial lake deposits are seen. A well-developed ice-contact delta and esker marks a recessional position of the Wisconsinan glacier and the northeastern ice-defended boundary of glacial Lake Sciota. (B) Fold mullions and many sedimentary features are present in the Decker Formation in this overturned syncline. (C) Well-developed mudcracks, edgewise conglomerate, and other structures suggestive of supratidal deposition are of interest in the Poxono Island Formation. Cleavage that warps bedding slickensides is common in the Bossardville.

Abandoned quarries in the Bossardville Limestone to right and left.

View to right of Cherry Valley; Godfrey Ridge on left;
View to right of Cherry Valley; Godfrey Ridge on left; rounded ridge in the middleground is underlain by the Bloomsburg Red Beds in the southwest-plunging Kemmererville anticline; northwest-dipping quartzites in the Shawangunk Formation hold up Kittatinny Mountain on the skyline.

Poxono Island Formation exposed in creek to right.

Near-vertical Bossardville Limestone on left.

Flat floor underlain by glacial lake clays, etc.
Flat floor of Cherry Valley on right partly underlain by glacial lake clays, silts, and sands. Kittatinny Mountain forms skyline to right.

Stormville Member of the Coeymans Fm
Village of Stormville, type locality of the Stormville Member of the Coeymans Formation.

Whiteport Dolomite Member of the Rondout Fm
Very well developed columnar mud cracks in the Whiteport Dolomite Member of the Rondout Formation on left.

Kame ahead.
Low hill ahead is a kame containing Wisconsinan sand and gravel.

Coeymans Formation on left in slump block.

Ridgeley Sandstone in float on left.
Ridgeley Sandstone, which caps Godfrey Ridge, in float on left.

The Bloomsburg Red Beds in Kemmererville anticline to right rises up-plunge.

Stormville Member of the Coeymans Fm
Good exposures of the Stormville Member of the Coeymans Formation in steep slope beyond farm house on right.

Cross Cherry Creek.

Entering Wildcat Hollow.
Exposures of northwest-dipping red and green clastic rocks of the Bloomsburg Red Beds in the northwest limb of the Kemmererville anticline.

Crest of Kemmererville anticline.
South of here the rocks dip gently southeast.

Crest of Kemmererville anticline.

Southeast limb of Kemmererville anticline.
Turn right and descend southeast limb of Kemmererville anticline.

Trough of Poplar Valley Syncline.
Note ten foot long (3 m) long glacial erratics of Buttermilk Falls Limestone in creek to right.

Contact Shawangunk Fm / Bloomsburg Red Beds
Contact between the Shawangunk Formation and Bloomsburg Red Beds. Ascend (we hope) steep dirt road to crest of Kittatinny Mountain.

Crest of Kittatinny Mountain.
Proceed east (to left) along dirt road to Stop 4. The quartzites of the Shawangunk Formation here are overturned to the southeast, dipping about 50°. As we proceed eastward, the rocks become vertical and then dip moderately northwest at Delaware Water Gap.

Microwave Tower of AT&T on right.

Good view to left.
Good view of Kemmererville anticline, Godfrey Ridge, and the Pocono Mountains to the north (left).

STOP 4. Delaware Water Gap Overlook.
Stratigraphy And Structure Of The Shawangunk Formation: Origin Of Wind And Water Gaps; Nature Of The Ordovician-Silurian Contact; Summary Of Trip.
Park at end of road. Disembark and follow Appalachian Trail to edge of Delaware Water Gap.
The three members of the Shawangunk Formation, basically two conglomeratic quartzite units separated by a sequence of argillites and quartzites, and the lower part of the Bloomsburg Red Beds, are well exposed in the gap. The Minsi and Tammany Members of the Shawangunk are interpreted to have been deposited by braided streams flowing off highlands uplifted during the Taconic orogeny, whereas the Lizard Creek Member of the Shawangunk represents a complex transitional continental-marine environment (Epstein and Epstein, 1967. 1969, 1972).
Fining-upward sequences in the Bloomsburg are indicative of meandering streams. The contact between the Shawangunk and the Bloomsburg, based on an upward change from gray to red rocks, is extremely irregular, particularly near the village of Delaware Water Gap, 1.5 miles (2.4 km) to the northwest (see fig. 10 and Epstein 1973).
The Shawangunk in the gap dips moderately to the northwest (figs. 10 and 11) and contains many small satellitic folds. The beds reverse their dip in the Dunnfield Creek syncline, and do so again in the Cherry Valley anticline. We will see the northwest limb of the Cherry Valley anticline at the toll booth on Interstate 80 in the village of Delaware Water Gap. Many small undulations, wedges, and bedding slips in the Bloomsburg are superimposed on the larger Dunnfield Creek syncline. Movement of these structures suggests sliding to the northwest.
The regional strike between the Martinsburg and the Shawangunk in this area differs by about 15°, and the Ramseyburg-Pen Argyl contact in the Martinsburg is buried beneath the Shawangunk 1.2 miles (2 km) southwest of the gap. The difference in structural trends is very apparent in the field, on aerial photographs, and high-altitude imagery. This regional Taconic unconformity is well documented. On the basis of several lines of reasoning, however, I believe the cleavage in the Martinsburg at the gap to be Alleghenian in age. Note that the cleavage in the Martinsburg arches, whereas bedding maintains its general northwest dip (fig. 10). indicating that the arching was not caused by external rotation during post-Taconic deformation. Rather, I believe that the arching is due to a pressure-shallow mechanism whereby cleavage in pelitic rocks adjacent to more competent rocks fans away from the axis of a syncline (see Epstein and Epstein, 1969, p. 166-167). The upper limb of the syncline in the Shawangunk is eroded away, of course, but it can be seen down-plunge to the southwest where the beds are overturned, such as at Totts Gap.
Glacial striae and roches moutonnees are common on top of Kittatinny Mountain. They trend about due south, but the Wisconsinan glacier was deflected more to the southwest on the slopes and in the valleys, following the trend of the topography.
For many years there have been numerous discussions on the origin of wind and water gaps and how that origin relates to Appalachian geomorphic development. Basically, two contrasting viewpoints have been presented. One favors coincidental location of the gaps due to superposition from a coastal-plain cover (e.g., Johnson, 1931). The other argues for northwestward headward erosion from the original drainage divide to the southeast along lines or points of structural weakness. The test of superposition, according to Strahler (1945), was to show lack of structural control for the location of the gaps.
For 40 miles (64 km) along Kittatinny and Blue Mountains and the ridges to the north, I have mapped the geology at 12 major gaps in Pennsylvania and New Jersey. The gaps are located where one or more of the following geologic conditions exist: (1) folds die out within short distances, (2) beds dip steeply and resistant units have narrow outcrop widths, and (3) there is more intense local folding or shearing than nearby (see Epstein, 1966).
At Delaware Water Gap the crest of Kittatinny Mountain in Pennsylvania is offset 800 feet (245 m) to the southeast from the trend of the crest in New Jersey. However, a transverse fault is not present through the gap (as has been suggested by several workers), because the contacts of the three members within the Shawangunk are not displaced at river level (fig. 10). The offset of the ridge crest is due to downward flexing of the rocks on the Pennsylvania side whereas the rocks maintain a constant dip on the New Jersey side (fig. 12). The flexure can be seen by looking west from the New Jersey bank. The abrupt change in strike at the gap site must have resulted in extensive fracturing in the brittle Shawangunk. Structural control is therefore thought to have determined the location of the gap. Also, the Bloomsburg Red Beds just north of the gap are involved in about 15 folds that die out rapidly to the southwest, including the large Dunnfield Creek syncline and Cherry Valley anticline. This structural situation is present at other large gaps, such as Wind Gap and Lehigh Gap. The rocks were probably more highly sheared here, and resistance to erosion was less than in the areas between gaps where similar folds were not observed.
Thus, data supporting structural control for location of the gaps does not favor the concept of regional superposition. Rather, it favors those hypotheses that maintain that gaps are located in zones of structural weakness where erosion was most effective during the course of stream competition, along the ancestral drainage divide.
Time permitting, we will summarize the themes of this trip: structural comparisons of the several lithotectonic units, ages of deformation, regional stratigraphic framework, history of sedimentation, and Quaternary history.

Crest of Kemmererville anticline.
Crest of Kemmererville anticline. Descend northwest limb of anticline. A thin layer of till caps bedrock in most of this area.

Stratified Wisconsinan sand and gravel in kames
Stratified Wisconsinan sand and gravel in kames underlying golf course on left right. Godfrey Ridge, underlain by complexly folded Upper Silurian and Lower Devonian rocks, forms the ridge beyond Cherry Valley.

NW dipping rocks in the Shawangunk Formation
Exposures are northwest-dipping rocks in the Shawangunk Formation on the northwest limb of the Cherry Valley anticline.

Shawangunk Formation on right dips to south
Exposures of Shawangunk Formation on right dip to south on the southeast limb of the Cherry Valley anticline.

Undulations in the Bloomsburg Red Beds
Undulations in the Bloomsburg Red Beds on left are superimposed on the northwest limb of the Dunnfield Creek syncline. Many wedges and bedding-plane slips are exposed in these rocks. Note the well-developed cleavage.

Water-worn and glacially striated Bloomsburg on left.

Kame terrace on left.

Shawangunk Fm / Bloomsburg Red Beds contact
Contact between Shawangunk Formation and Bloomsburg Red Beds covered on left.

Massive conglomeratic quartzites on left.
Massive conglomeratic quartzites of the upper (Tammany) member of the Shawangunk Formation on left.

(Lizard Creek) member of the Shawangunk Fm
Interbedded quartzite. siltstone, and shale in the middle (Lizard Creek) member of the Shawangunk Formation on left.

(Mimi) member of the Shawangunk Fm
Quartzites of the lower (Mimi) member of the Shawangunk Formation on left. Note to the right that the Shawangunk dips about 45° at river level and is warped to lesser dips halfway up the mountain (fig. 12). Note gabions retaining the colluvium on left. The contact of the Martinsburg and Shawangunk is buried here but was discussed by Beerbower (1956).

4A: ALTERNATE STOP 4
In case we do not go to Stop 4, follow this road log to alternate Stop 4, picking up at mileage 36.9.

Alternate STOP 4

Steeply dipping beds, and well developed cleavage.
Steeply dipping Port Ewen Shale of the Helderburg Group, Shriver Chert and Ridgeley Sandstone of the Oriskany Group, and Esopus Formation on left. Note well-developed cleavage in the Esopus.

Crest of Godfrey Ridge
Crest of Godfrey Ridge supported by siliceous siltstones in the Esopus Formation. The road descends through several folds in the Esopus and Schoharie Formations and Buttermilk Falls Limestone.

Slightly overturned Buttermilk Falls Limestone on right.

Overturned Schoharie Formation on right.
The road ascends through several folds.

Crest of Godfrey Ridge seen on left
Crest of Godfrey Ridge, underlain by the Esopus Formation seen on left with well-developed cleavage. View to right of Cherry Valley, the Kemmererville anticline underlain by the Bloomsburg Red Beds in the middleground, and Kittatinny Mountain, underlain by Shawangunk quartzites, in the skyline.

Esopus Formation on left.

Ridgeley Sandstone on left underlain by Shriver Chert.

Port Ewen Shale on left.
The road descends through various Wisconsinan deposits.

Northwest·dipping gray sandstone Shawangunk Formation on right.

Crest of Cherry Valley anticline.
Note the lateral gradation of red, green, and gray beds at this contact between the Shawangunk Formation and Bloomsburg Red Beds.

Resort Point Overlook on left.
Note the undulations in the Bloomsburg across the river which are superimposed on the northwest limb of the Dunnfield Creek syncline. Cleavage is well developed and wedges and bedding slips are common.

Note "Indian Head" in cliffs
Note "Indian Head" in cliffs of the Shawangunk on the left side of the gap.

Shawangunk-Bloomsburg contact on right.

ALTERNATE STOP 4.
Stratigraphy And Structure Of The Shawangunk Formation: Origin Of Wind And Water Gaps; Nature Of The Ordovician-Silurian Contact; Summary Of Trip.
Copied from description for STOP4:
The three members of the Shawangunk Formation, basically two conglomeratic quartzite units separated by a sequence of argillites and quartzites, and the lower part of the Bloomsburg Red Beds, are well exposed in the gap. The Minsi and Tammany Members of the Shawangunk are interpreted to have been deposited by braided streams flowing off highlands uplifted during the Taconic orogeny, whereas the Lizard Creek Member of the Shawangunk represents a complex transitional continental-marine environment (Epstein and Epstein, 1967. 1969, 1972).
Fining-upward sequences in the Bloomsburg are indicative of meandering streams. The contact between the Shawangunk and the Bloomsburg, based on an upward change from gray to red rocks, is extremely irregular, particularly near the village of Delaware Water Gap, 1.5 miles (2.4 km) to the northwest (see fig. 10 and Epstein 1973).
The Shawangunk in the gap dips moderately to the northwest (figs. 10 and 11) and contains many small satellitic folds. The beds reverse their dip in the Dunnfield Creek syncline, and do so again in the Cherry Valley anticline. We will see the northwest limb of the Cherry Valley anticline at the toll booth on Interstate 80 in the village of Delaware Water Gap. Many small undulations, wedges, and bedding slips in the Bloomsburg are superimposed on the larger Dunnfield Creek syncline. Movement of these structures suggests sliding to the northwest.
The regional strike between the Martinsburg and the Shawangunk in this area differs by about 15°, and the Ramseyburg-Pen Argyl contact in the Martinsburg is buried beneath the Shawangunk 1.2 miles (2 km) southwest of the gap. The difference in structural trends is very apparent in the field, on aerial photographs, and high-altitude imagery. This regional Taconic unconformity is well documented. On the basis of several lines of reasoning, however, I believe the cleavage in the Martinsburg at the gap to be Alleghenian in age. Note that the cleavage in the Martinsburg arches, whereas bedding maintains its general northwest dip (fig. 10). indicating that the arching was not caused by external rotation during post-Taconic deformation. Rather, I believe that the arching is due to a pressure-shallow mechanism whereby cleavage in pelitic rocks adjacent to more competent rocks fans away from the axis of a syncline (see Epstein and Epstein, 1969, p. 166-167). The upper limb of the syncline in the Shawangunk is eroded away, of course, but it can be seen down-plunge to the southwest where the beds are overturned, such as at Totts Gap.
Glacial striae and roches moutonnees are common on top of Kittatinny Mountain. They trend about due south, but the Wisconsinan glacier was deflected more to the southwest on the slopes and in the valleys, following the trend of the topography.
For many years there have been numerous discussions on the origin of wind and water gaps and how that origin relates to Appalachian geomorphic development. Basically, two contrasting viewpoints have been presented. One favors coincidental location of the gaps due to superposition from a coastal-plain cover (e.g., Johnson, 1931). The other argues for northwestward headward erosion from the original drainage divide to the southeast along lines or points of structural weakness. The test of superposition, according to Strahler (1945), was to show lack of structural control for the location of the gaps.
For 40 miles (64 km) along Kittatinny and Blue Mountains and the ridges to the north, I have mapped the geology at 12 major gaps in Pennsylvania and New Jersey. The gaps are located where one or more of the following geologic conditions exist: (1) folds die out within short distances, (2) beds dip steeply and resistant units have narrow outcrop widths, and (3) there is more intense local folding or shearing than nearby (see Epstein, 1966).
At Delaware Water Gap the crest of Kittatinny Mountain in Pennsylvania is offset 800 feet (245 m) to the southeast from the trend of the crest in New Jersey. However, a transverse fault is not present through the gap (as has been suggested by several workers), because the contacts of the three members within the Shawangunk are not displaced at river level (fig. 10). The offset of the ridge crest is due to downward flexing of the rocks on the Pennsylvania side whereas the rocks maintain a constant dip on the New Jersey side (fig. 12). The flexure can be seen by looking west from the New Jersey bank. The abrupt change in strike at the gap site must have resulted in extensive fracturing in the brittle Shawangunk. Structural control is therefore thought to have determined the location of the gap. Also, the Bloomsburg Red Beds just north of the gap are involved in about 15 folds that die out rapidly to the southwest, including the large Dunnfield Creek syncline and Cherry Valley anticline. This structural situation is present at other large gaps, such as Wind Gap and Lehigh Gap. The rocks were probably more highly sheared here, and resistance to erosion was less than in the areas between gaps where similar folds were not observed.
Thus, data supporting structural control for location of the gaps does not favor the concept of regional superposition. Rather, it favors those hypotheses that maintain that gaps are located in zones of structural weakness where erosion was most effective during the course of stream competition, along the ancestral drainage divide.
Time permitting, we will summarize the themes of this trip: structural comparisons of the several lithotectonic units, ages of deformation, regional stratigraphic framework, history of sedimentation, and Quaternary history.

Cold Air Cave on right.
Cave is formed by a large slab of quartzite float resting on smaller stones. Cold air stored in the colluvium flows down through the rocks and into the cave. It was used for storage of soft drinks more than 50 years ago (Stone, 1932).

Ramseyburg member of the Martinsburg Fm
Outcrop of the middle (Ramseyburg) member of the Martinsburg Formation on right. Beds dip 32° NW and cleavage dips 7° NW.

Very coarse kame-terrace deposits on right.
These deposits flank both sides of Delaware Valley for more than 1 mile downstream.

Quarries in Bushkill member of the Martinsburg Fm
Two quarries hidden in narrow valleys on right are in the lower (Bushkill) member of the Martinsburg Formation.

5: ALLEGHANIAN THRUST FAULTS IN THE KITTATINNY VALLEY, NEW JERSEY
Avery Ala Drake, Jr., and Peter T. Lyttle
U. S. Geological Survey
Reston, Virginia
Major thrust faults involving both Proterozoic basement and Cambrian and Ordovician sedimentary rocks have been known in the Kittatinny Valley at least since the geologic mapping that resulted in the New Jersey State Geologic Map (Lewis and Kummel, 1910-12) and the Raritan Folio (Bayley and others, 1914). Three important thrust faults, the Jenny Jump, Portland, and Federal Springs, display quite different tectonic styles at the present level of erosion and, thereby, serve as showpieces of thrust fault tectonics for this part of the central Appalachian orogen. The purpose of this field trip is to demonstrate these three thrust faults and to present evidence for their late, probably Alleghanian age. In addition, attendant structural features such as autoclastic melange and chert mylonite will be shown.
Road log
The field trip begins in the parking lot at Rutgers-Newark and reaches the Kittatinny valley by the garden state parkway and interstate 280 and 80. Subsequent to stop 9, the trip returns to Rutgers-Newark by route 206, interstates 80 and 280, and the Garden State Parkway. Geologic notes are provided for the route 206 segment of the return. Field trip stops 1-8 are in the Blairstown 7.5-minute quadrangle and stop 9 is in the Newton East quadrangle. (A copy of these two quadrangles will be provided to each participant.) The trip route also traverses the Tranquility, Newton East, and Stanhope quadrangles.

5: ALLEGHANIAN THRUST FAULTS IN THE KITTATINNY VALLEY, NEW JERSEY

Exposures of sandstone and mudstone
Alternating beds of red sandstone and mudstone with a few thin interbeds of gray siltstone and dark gray to black micaceous shale, occurring below the first overpass. These siltstones yield a probable late Norian palynoflora and occur about 1100 m below the First Watchung Mountain Basalt (Cornet and Traverse, 1975, p. 27). Sporadic exposures of sandstones and mudstones with fining-upward sequences, characteristic of meandering streams, occur along Interstate 280 for the next 4.4 miles.

Basalt of the First Watchung Mountain
Contact with the underlying red beds is concealed. Note: characteristic radial columnar joint pattern.

Basalt of the Second Watchung Mountain
Contact with the underlying beds is concealed.

Basalt of the Third Watchung Mountain
Basalt of the Third Watchung Mountain is exposed to the south of the highway.

Passaic River Valley
The valley is underlain with glacial clays and silt that were deposited in Glacial Lake Passaic. The lake formed as glacial meltwaters were impounded between the New Jersey Highlands to the west and the Watchung Mountains to the south and east (see Kummel, 1940).

First preCambrian rocks
Water tower on right (left?) is on Proterozoic (Precambrian Y) rocks of the N.J. Highlands.

Begin climb from Jurassic-Triassic Basin into the Highlands.

Steeply dipping amphibolites.
First roadcuts of Highlands rocks, here steeply dipping amphibolites.

Biotite-quartz-plagioclase gneiss.
Outcrops of very rusty metasedimentary biotite-quartz-plagioclase gneiss.

Field area of Paul Sims
This was field area of famous Precambrian geologist Paul Sims. The ridge to right front is held up by the Silurian Green Pond Conglomerate.

Cruddy outcrops of Proterozoic gneiss.

Lots of glacial till on left.

Biotite-quartz-plagioclase gneiss
Large outcrop of strongly layered biotite-quartz-plagioclase gneiss of Proterozoic age on right.

Outcrops of hornblende granite of Proterozoic age.

Outcrops of Proterozoic rocks.

Musconetcong River
Formerly a great trout stream, now a temporary habitat for fish between hatchery and skillet.

Continuous outcrops of Proterozoic rocks
Continuous outcrops of Proterozoic rocks on Allamuchy Mountain. These rocks are in the core of the Allamuchy nappe of the Musconetcong nappe system of the Reading Prong nappe megasystem. The rocks cropping out at the rest stop to the left and above the highway are severely deformed and contain several flat thrust faults.

Scenic overlook.
If weather is fine, bus will pull off here and we will give a short briefing on the regional geology and this field trip. Looking north from this place, one has an excellent view of the Kittatinny Valley and Jenny Jump Mountain.

Bold outcrops of Proterozoic rocks.

Granite gneiss containing mafic segregations
This outcrop of granite gneiss contains mafic segregations of plagioclase, epidote, garnet and magnetite surrounded by a rind of almandine garnet in a more felsic matrix of potassium feldspar, quartz, plagioclase, epidote, and accessories. Foliation appears to parallel gneissic layering and is oriented N. 45° E., 39° SE. Pegmatites are roughly parallel to foliation, but upon close inspection are seen to cut it.

Entering Bear Swamp.
Rocks in this area are Allentown Dolomite of Late Cambrian age.

Nice outcrop of Allentown Dolomite.
Beds strike N. 82° W., and dip 15° NE, cleavage strikes N. S5° W. and dips 22° NE, their intersection, roughly parallel to axes of small folds, plunges 14° N. 18° W. The beds face up and are probably in the upper limb of the Allamuchy nappe.

Begin the ascent of Jenny Jump Mountain
Here we are crossing the trace of the Shades of Death thrust which brings rocks of the Allamuchy nappe onto rocks of the Jenny Jump klippe of the Jenny Jump thrust sheet. The Proterozoic rocks here are dominated by a sequence of marble, amphibolite, and lesser calcsilicate rock.

Lower Paleozoic rocks beneath the thrust fault
We have passed through the Proterozoic rocks of the Jenny Jump klippe and here enter a sequence of lower Paleozoic rocks beneath the thrust fault. Here the outcrops are Epler Formation of the Beekmantown Group of Early Ordovician age. These outcrops contain fairly abundant solution collapse breccia. Many bedding surfaces in these rocks are also thrust faults and a fair amount of carbonate mylonite has been formed. Axes of small folds plunge 5° S 25° E; beneath the Proterozoic rocks of the Jenny Jump klippe.

Nice outcrops of Allentown Dolomite.
Here we are about on the crest of an anticline which plunges 5° N 45° E. Beds face up as shown by good algal stromatolites.

Long continuous outcrop
Long continuous outcrop beginning in Allentown Dolomite, Rickenbach Dolomite, Epler Formation, and Ontelaunee Formation. (See Markewicz and Dalton, this Guidebook.)

Epler / Rickenbach contact
Large outcrop of sandy, mottled, laminated dolomite of the Epler Formation. The contact with the Rickenbach Dolomite is about in middle of this cut. It is placed at the contact of laminated, burrowed, mottled, finely crystalline dolomite (Epler) with thick-bedded, dark-medium-gray, medium crystalline dolomite (Rickenbach). Rock contains abundant cascade-type folds which plunge 5°-10° N 25° E.

Outcrops of Jacksonburg Limestone.
Most of rock here is crystalline limestone but some beds are dark-gray, more argillaceous cement rock. Axes of small folds here plunge 20° N 5° W. Slickensides on bedding surfaces plunge down the dip.

More outcrops of Jacksonburg Limestone.

More outcrops of Jacksonburg Limestone.
More outcrops of Jacksonburg Limestone. A lot of conglomerate here. Outcrops to south of Interstate are Bushkill Member of the Martinsburg Formation. Slaty cleavage, which strikes N 60° E and dips 20° NW., is principal planar element in these rocks. The cleavage surfaces are marked by a strong extension lineation which plunges 5° N 35° W. and crenulations which are nearly horizontal N. 70° E. Strong crenulation cleavage strikes N. 70° E. and dips 75° SE.

Bushkill Member of Martinsburg Fm
We are driving on Bushkill Member of Martinsburg Formation. Outcrops to right are Allentown Dolomite in the large Hope klippe of the Jenny Jump thrust sheet. The dolomite beds face up, dip gently northwest, and contain abundant algal stromatolites and oolite.

Here we are at the base of the Hope klippe.
The outcrop to the right is oolitic, shaley, Allentown Dolomite, probably the lowest beds of that unit. The beds dip gently to the northwest and face up.

Hope, a pre-revolutionary Moravian settlement
Entering the town of Hope which is a pre-revolutionary Moravian settlement.

Outcrop on right is Leithsville Formation
Outcrop on right is Leithsville Formation of Early and Middle Cambrian age. The gently northwest dipping rocks are right at the sole of the Hope klippe. They dip gently northwest, have a vague mylonitic foliation which strikes N. 45° E. and dips 18° NW., and a general mangled appearance.

Outcrops on right are Jacksonburg Limestone.
The rock here is well-bedded, calcarenite grainstone that contains abundant fossil hash and small scattered pebbles of dolomite. The beds strike N. 75° W. and dip 25° NE. They have a cleavage which strikes N. 55°E. and dips 15° SE.; this cleavage is marked by an extension lineation which plunges approximately down the dip. The intersection of the cleavage with the bedding plunges 7° N 88° E. These rocks are autochthonous to the Jenny Jump thrust sheet and belong to an as yet unnamed tectonic element of the Musconetcong nappe system of the Reading Prong nappe megasystem.

Ontelaunee Fm of Beekmantown Group
Outcrop on right is Ontelaunee Formation of Beekmantown Group. This is Field Trip Stop 2 to which we will return.

Poor outcrop of Allentown Dolomite
Poor outcrop of Allentown Dolomite on lawn on the right. Abundant, excellent outcrops of Allentown on wooded knoll to to the east.

STOP 1. Jenny Jump klippe of Jenny Jump thrust sheet
Speaker, Peter Lyttle.
(Field trippers will disembark, bus driver will take bus to top of hill to Hissim Road to turn around. He should wait there for 30 minutes, and return down the hill to pick up the field trip in front of the house at the base of hill.)
We are on the northwest edge of the main mass of the Jenny Jump thrust sheet on the northwest side of Jenny Jump Mountain. The Proterozoic rocks we will be looking at here are primarily hornblende granite gneisses with minor fine-grained mafic dikes. These rocks structurally overlie the lower Paleozoic rocks of the valley that we have just driven through. Although the Jenny Jump thrust is nowhere exposed, there are several locations along the north side of Jenny Jump Mountain where outcrops of Paleozoic carbonate with structures dipping to the southeast occur within a few tens of meters of the Proterozoid gneisses. It is clear in map pattern (see Figure 4) that the Jenny Jump thrust truncates both contacts and structures in Paleozoic rocks.
In order to see all of the structures mentioned below, it is necessary to hike a hundred meters or so along the side of Jenny Jump Mountain in this area of semi-continuous outcrop. Almost all of the structures can be seen in several places and the diligent tripper should be able to find them all on his/her own. The most important structure to note at this outcrop is well-developed foliation that is, in most places, parallel to compositional layering and is axial planar to the rarely observed earliest isoclinal folds that are presumably Grenville in age. This foliation is seen in both the gneiss and mafic dikes. The orientation of the dikes appears to roughly parallel the foliation, but can by at an angle to compositional layering, indicating that the dikes intruded either during or before this early folding episode. This foliation is folded by a later event interpreted to be the emplacement of the Jenny Jump thrust sheet. Over most of Jenny Jump Mountain the foliation strikes roughly N. 60°E. and dips 30-40° to the southeast. However, at several places along the northwest edge of Jenny Jump Mountain. it is common to find the foliation folded by large, open, upright to slightly overturned folds .
There has been considerable slip on many foliation planes (evidenced by slickensides) and if the rocks at this outcrop are not wet or in the shade, the field tripper will note many narrow zones of mylonite that are roughly parallel to the foliation. Locally, these zones of mylonite are brecciated. These outcrops are very near the sole of the Jenny Jump thrust sheet and it is likely that the mylonitization and brecciation are related to the emplacement of the thrust sheet.
In one area of these outcrops, a thin mafic dike is cut by numerous small-scale thrusts spaced 3-10 cm apart. The sense of movement is always toward the NNW.
The gneisses here are quite magnetic, the magnetite probably being produced with chlorite at the expense of hornblende. Very little fresh hornblende is seen in thin section. Quartz, microcline oligoclase, minor hornblende and magnetite, and accessory zircon and apatite make up the bulk of the gneisses. The oligoclase and hornblende are commonly altered, and the quartz is highly strained and occurs in long sheared out stringers.

STOP 2. Bedding-parallel faults in the Ontalaunee Fm
Speaker. Peter Lyttle. (Driver pull bus onto turnout on left side of road.)
This will be a very quick stop to illustrate bedding-parallel shear and mylonitization in the Lower Ordovician Ontalaunee Formation. Other outcrops show this more extensively, but this outcrop is logistically more feasible for this field trip. Although pressure solution is the dominate deformation mechanism producing tectonic shortening in the carbonate rocks of the Great Valley, both the rocks within and tectonically beneath the Jenny Jump thrust sheet exhibit extensive faulting parallel to bedding. This shearing is commonly, though not exclusively, concentrated in chert rich zones within dolomites. The chert need not be in continuous beds. Zones of nodular chert and very thin stringers appear sufficient to provide a contrast or inhomogeneity in rock strength sufficient to concentrate shearing within these areas.
Although this stop has well developed zones of mylonite concentrated along chert zones that have behaved ductily and show small drag folds (see fig. 7), other outcrops show a transition from brittle to ductile structures in these zones. This transition is achieved through a continual change in the mechanical properties of the rock probably because of the reduced grain size, water weakening or localized frictional heating rather than changes in external parameters such as external temperature and confining pressure. Initially, the dolomite and chert together form a breccia with pieces of dolomite ranging in size from 1·15 cm and pieces of chert ranging in size from 1 mm to 5 cm. Continued shearing pulverizes the chert which then acts as a fine-grained matrix surrounding pieces of dolomite which are still angular and recognizable, yet smaller, pieces of dolomite. At this stage the rock has a "frothy" appearance and the chert has lost its black translucence. More shearing produces a mylonite, such as the example at this stop (see fig. 6), and there are no longer any recognizable pieces of dolomite. Everything has been finely comminuted and the rock has a fluxion structure. At this outcrop the fluxion structure is folded into small drag folds.
It is important to realize that the fluxion structure or "cleavage" developed in these zones does not represent regional cleavage. The orientation of the "cleavage" or mylonitic foliation in these shear zones is related to the original attitude of the chert zones and is parallel to the shear zones. Regionally. this "cleavage" is best developed in narrow shear zones in and immediately beneath the large scale thrusts and is essentially parallel to these thrusts. The Jenny Jump thrust was slightly above the present erosional surface at this stop and may have caused the subsidiary thrusting and mylonitization at this locality.
The Ontelaunee Formation at this stop is very finely to finely crystalline, light to medium gray, medium- to thick-bedded dolomite with thin beds of chert. Fabric information: bedding N. 67° W. 15° NE; extension lineation 13° S 38° E; fold axis in mylonite 14° N 48° E.; joints N 85° E. 67° SE. and N. 15° E. 15° SE.

Outcrop at Jacksonburg Limestone on left.

Sole of Hope Klippe.
Outcrops of Allentown Dolomite on the left. Beds strike. N. 75°, and dip 25° NW. Rocks face up as shown by abundant algal stromatolites.

Outcrops of Allentown Dolomite on left.
Here there are dolorudite beds and orthoquartzite lenses. Big, rounded bedding surfaces suggest algal stromatolites but internal ornamentation is not obvious.

Outcrops of Allentown Dolomite on right.
Rock here is mostly oolite with some oolite matrix conglomerate.

Outcrops of oolitic Allentown Dolomite on right.
Rock has strongly developed extension fractures which strike N.48° E. and dip 65° NW.

Cross small stream
Cross small stream which follows a steep normal fault which fragments the Hope klippe in this area.

STOP 3. Hope klippe of Jenny Jump thrust sheet
Speaker. Avery Drake.
(Park in Methodist Church parking lot on right, unless church services are being held; if services are being held, park on left side of street near Honeywell Hall.)
Here we are on the Bushkill member of the Martinsburg Formation at the northwest border of the Hope klippe. The bounding thrust fault lies in the stream a short distance to the southeast, and carbonate rocks of the klippe crop out on the ridge to the southeast of the streams. The klippe here has been fragmented by a later normal fault which has brought rocks of the Epler Formation into contact with the Bushkill. We will first observe rocks of the Bushkill on the slope to the southeast of Green Chapel Cemetery. The Bushkill here is very disturbed. In the fall of 1978 the following fabric elements could be measured: bedding, N. 30° E., 65° SE. (inverted); slaty-cleavage, N. 20° E., 40° SE.; and pseudo·slaty cleavage, N.38°E. 52°SE.; strain slip cleavage, N. 50°. 45° NW.; intersection of bedding and slaty cleavage and pseudo-slaty cleavage, 20°S.55° W., crenulations, 16° N. 36° E.; extension lineation on slaty cleavage, 38 °S. 50°E.; and a joint, N. 60° W. 60° SW. There are many folds in bedding, but the details have not been worked out. The pseudo-slaty cleavage is thought to result from the emplacement of the Jenny Jump thrust sheet. At this place the planar elements, save the strain-slip cleavage which results from post-klippe emplacement folding, dip beneath the carbonate rocks and the extension lineation plunges beneath them. Bushkill is also exposed in pavement outcrops in the secondary road to the southwest of the Mt. Hermon Road.
After observing the Bushkill, we will examine the outcrops of Epler on the ridge to the southeast. The rock there is finely crystalline to medium crystalline, light gray to medium-gray dolomite which contains thin partings, lenses, and very thin beds of orthoquartzite. The outcrop contains abundant solution collapse breccia. Many of the blocks in the breccia are quite large. Bedding in the outcrop is N. 45° E. 38° NW. A poor fracture cleavage has the altitude N. 10° E. 55° SE. Return to bus and continue northwest on Mt. Hermon road.

Northwest border of Hope klippe.
Cross small stream which marks the northwest border of Hope klippe.

Ramseyburg Member of Martinsburg Fm
Outcrop of Ramseyburg Member of Martinsburg Formation on the left.

Poor outcrops of Ramseyburg on the right.

More poor outcrops of Ramseyburg on the right.

Small pond on right.
Geology along here is obscured by ground moraine.

Outcrops of Ramseyburg on left.

Mangled outcrops of Allentown dolomite
Mangled outcrops of Allentown dolomite of Hope klippe on the left. Continue north .15 mile distance and pull into turn-off on right.

STOP 4: Northwest boundary of Hope klippe
Speaker, Avery Drake.
Here rocks of the Bushkill Member crop out in a cut at road level and carbonate rocks of the klippe crop out on the hill above. This is not a good exposure of the Bushkill, but it is extremely important as the rock here is an auto clastic tectonic melange. Careful observation will reveal phacoids, "tectonic fish" of graywacke and slate, some of which are fold hinges, within the mangled slate matrix (see fig. 8). PLEASE NO HAMMERING OR PLUCKING OF "TECTONIC FISH." There are at least two flat cleavages interlacing within this outcrop, presumably the slaty and pseudo-slaty cleavages viewed elsewhere. The prominent foliation in this outcrop is due E. 10° S.
Here the carbonate rock of the klippe is Allentown Dolomite. The outcrop has a jumbled appearance and bedding is difficult to determine but seems to be about N 10° W., 10° NE. Most of the rock is rather nondescript crystalline dolomite, but there is a fair amount of dolarenite and some oolite, desiccation dolorudite, and dark-gray chert lenses and skims. In addition, some curved forms without internal ornamentation are suggestive of algal stromatolites. It is quite clear at this stop that the carbonate rocks of the klippe lie above the Bushkill. Reboard the bus and continue northeast on Hope Road.

Turn right on Mud Pond Road
Turn right on Mud Pond Road (10,000 pound limit). This road essentially follows a normal fault which has fragmented the Hope klippe in this area, carbonate rocks of the klippe on the right, Martinsburg on the left. Carbonate rock for first .2 mile along road is Rickenbach Dolomite.

Mangled outcrops of Allentown Dolomite on right.

Outcrops of severely mangled Martinsburg.
Rock here is an autoclastic melange consisting of phacoids and lenses of graywacke and slate "swimming" in slate. Extension lineation plunges essentially down the dip of the principal foliation. The klippe sole here lies a few feet up the hill to the right.

Small pond on left.

Good pavement outcrop of Bushkill on the left.

Ramseyburg outcrop on the left.

Slate with graywacke
Outcrops of slate containing a few thin graywacke beds at intersection.

Bridge over small stream.
Bus will go a short distance farther and disembark the field trippers. It will then continue south on Ridgeway Road and turn around wherever possible, and return for the field trip in about 1/2 hour.

This carbonate rock constitutes the small Cooks Pond klippe.
Cooks Pond on the left. Outcrop of cherty, laminated, finely crystalline medium-dark-gray dolomite of the Epler Formation on the right. This carbonate rock constitutes the small Cooks Pond klippe.

Outcrops of Bushkill slate at intersection.

STOP 5: Silver Lake I klippe
Speaker, Peter Lyttle.
The Silver Lake I klippe is a tiny erosional remnant of the Jenny Jump thrust sheet that contains a strongly deformed and perhaps highly telescoped section of Proterozoic granite and Lower paleozoic dolomite (probably Cambrian Leithsville Formation). Although the two or three outcrops that we will examine at this stop may at first glance be a little disappointing, this single locality records much of the tectonic history that we are trying to present on this field trip. We will look at a small ledge of Proterozoic granite that records an early tectonic event of high strain, local mylonitization, and retrograde metamorphism. This first event is interpreted to have occurred during the Taconic orogeny. Later, these same rocks were severely brecciated and comminuted, but not recrystallized (see fig. 9) photomicrograph. Although most of the rock consists of quartz, perthite, and plagioclase, there are minor amounts of magnetite and chlorite that appear to be alteration products of a mafic mineral, probably hornblende. All the minerals, particularly the perthite and quartz are highly strained, brecciated and rotated and severely reduced in grain size. These later structures are interpreted to have been produced during emplacement of the Silver Lake I klippe as part of the much larger Jenny Jump thrust sheet in Alleghanian times.
This small klippe structurally overlies the Middle Ordovician Bushkill Member of the Martinsburg Formation. After the bus picks us up we will head back north along this road passing an outcrop of the Bushkill at the first intersection. At this locality the slaty cleavage dips southeast under the Silver Lake I klippe. South of Stop 5 near Camp Hope (approximately 1/2 mile) the slaty cleavage in the Bushkill dips consistently to the northwest. Therefore, the klippe is sitting in a broad synformal trough of the slaty cleavage. Although it is impossible to prove at this stop, the emplacement of the klippe postdates the formation of the slaty cleavage. We will establish this to the satisfaction of the skeptical field tripper at the last stop of the day, the Grand Union klippe.
The only structures recorded at this stop are a fairly flat mylonitic foliation, N. 16°E. 18° NW. and a steeper and later cleavage N. 78°E. 50° SE. These were both measured (with difficulty) in the highly weathered Proterozoic granite. The pervasive rusty weathering was probably facilitated by the extensive brecciation along the later fracture cleavage. The tiny outcrop of dolomite fractures in a rectilinear fashion no matter how small the pieces become. This may be related to the late fracture sets.

STOP 6: Ebenezer klippe
Speaker. Avery Drake
(At about the Ebenezer sign, the bus will pull off to the right and allow field trippers to disembark. The bus will continue up hill to intersection with Lake Wasigan Road and park. Field trippers will walk up hill examining the outcrops. This will be the lunch stop.).
The first outcrop to examine is just to the north of the small stream, The rock here is Ramseyburg Member of the Martinsburg Formation. Fabric elements measured here in the fall of 1978 include: bedding, N.52° E. 25° NW.; slaty cleavage, N. 48° W. 5°NE.; strain-slip cleavage, N. 25° E. 20° SE,: a joint, N. 44° W. 70° SW.; intersection of bedding and slaty cleavage, 7° N. 48° E.; and extension lineation, 3° N. 35° W. The reader will note that here the bedding, slaty cleavage, and extension lineation have been rotated from their normal southeast dips and plunge so as to dip and plunge beneath the carbonate rocks to the north.
The last outcrop of Ramseyburg is about 400 feet to the north and the first outcrop of the carbonate rock of the klippe is about 375 feet north of there. The rock of the klippe is Allentown Dolomite. There is a particularly good outcrop of Allentown about 225 feet farther north which contains all the characteristic rock types of that unit: algal stromatolites, oolites, dessication dolorudites, etc. The sedimentary structures show that the carbonate rocks face up. The subtle field trippers will have noted that Ramseyburg crops out about 30 feet to the south of this Allentown outcrop for a length of about 20 feet showing that the klippe here, like the Hope klippe, is fragmented by later normal faults. The beds in the Ramseyburg dearly dip beneath the carbonate rocks of the klippe. There are additional good outcrops of Allentown along the road to the east of Lake Wasigan.
We plan to have lunch around Lake Wasigan. This is far from a perfect place, but our choices are limited. Following lunch, board the bus.

Inverted Bushkill slate crops out on the left.

Excellent outcrop of Ramseyburg on the left.
Some beds here are more than 1 m thick.

Rocks here are Martinsburg Fm in the Musconetcong nappe system.

Crossing small stream.
We will cross the trace of the Portland thrust fault within a few feet. Here the slaty cleavage in the Martinsburg is marked by a strong extension lineation which plunges down the dip. The Portland thrust fault frames the very large Paulins Kill window.

Large outcrops of Allentown Dolomite.
These rocks are in the Lyon Station-Paulins Kill nappe which is exposed in the Paulins Kill window.

Allentown Dolomite crops out up Hope Road to the Left.

Outcrops of Allentown Dolomite
Outcrops of Allentown Dolomite in Lyon Station-Paulins Kill nappe on right. Rock is severely deformed, most bedding surfaces have served as fault surfaces. Outcrop is characterized by very abundant filled, northeast-trending extension fractures.

Small outcrop of Allentown Dolomite on knoll to right.

Small outcrop of Allentown Dolomite on right.

Very sandy Allentown Dolomite on right.
Outcrop of very sandy Allentown Dolomite on right. There are abundant orthoquartzite beds here.

Large outcrops of Epler Formation
Large outcrops of Epler Formation on the left. Rocks here include laminated sandy dolomite, laminated dark-gray dololutite, chert-ribbed finely crystalline dolomite, sandy medium to medium-coarse crystalline limestone, and excellent examples of solution collapse breccia. Axes of small folds here plunge 70° S 15° W., down the dip of the beds.

STOP 7 Portland thrust fault
Speaker Avery Drake
(Field trippers will disembark and examine outcrops along road to left. Bus will have to find some means of turning around. There is a small parking area along road to left. This stop is just above the abandoned grade of the New York Susquehanna and Western Railroad. This is a very narrow road and field trippers must use extreme caution.)
The first outcrop to observe is 500 feet along the road to the east. Here are slate outcrops of the uppermost Bushkill Member of the Martinsburg Formation. The slate contains abundant thin beds of graywacke. Fabric elements include: bedding, N. 85° E. 48°SE.; slaty cleavage, N. 72 ° E. 68° SE.; and intersection of bedding and slaty cleavage, 35° S 55° W.
The Portland thrust fault crops out about 375 feet farther to the east.The observations recorded here were made in October 1978 shortly after the road was widened. Winters are particularly hard on exposures in this area and no guarantee can be made as to what the quality of the exposure will be at the time of the field trip. In any case, the Portland fault was found to have the attitude of N.78° E. 48°SE. and the slate above the fault to the east an attitude of N. 80°E. 55° SE. The carbonate rock beneath the fault is thoroughly tectonized. It is mostly medium crystalline, medium-gray dolomite that contains some solution collapse breccia, flat-pebble conglomerate, and dark gray sparry calcite. Judging from stratigraphically lower outcrops of extremely cherty dolomite up the hill to the north, this rock probably belongs to the Ontelaunee Formation. The dolomite contains several movement zones beneath the major thrust which are marked by carbonate mylonite. Extension lineations on the thrust surface plunge 45°S 38° E. Post-thrust strain-slip cleavage has the attitudes of N. 80° E. 40° NW., and post-thrust crenulations plunge 10° S 70° E. There are outcrops of both Ontelaunee and Epler along the road to the east and excellent outcrops of Epler up the hill to the north. We may examine some of these rocks depending on available time. (Board buses and follow unnamed road back up the hill to the north.)

Trace of the Portland thrust fault
Crossing the trace at the Portland thrust fault, the frame of Paulins Kill window.

Inverted Bushkill slate
Outcrop of inverted Bushkill slate at road intersection on the right

Nice outcrops of Ramseyburg on the right.

More nice outcrops of Ramseyburg.
Sedimentation sequences in these rocks begin with a cross-laminated interval which pass up into a planar laminated interval which is overlain by pelite. They are, then Tcde turbidites and belong to turbidite Facies D of Walker and Mutti (1973). The cleavage in these rocks is marked by an extension lineation which plunges 35° S. 15° E.

Outcrops of Bushkill slate on left
Cleavage here is marked by an extension lineation which plunges 20° S. 48° E.

Outcrops of Bushkill slate on the right.
Extension lineation on cleavage here plunges 34° S. 25° E.

Rickenbach Dolomite in the small Alpha Klippe
Rickenbach Dolomite in the small Alpha Klippe crops out to the left. Allentown Dolomite in the even smaller Beta Klippe crops out in the woods about .25 miles to the east-northeast. Both these klippen rest on Ramseyburg and are shown but not labeled on figure 1.

Rock is Bushkill.

STOP 8: Federal Springs thrust fault
Speaker, Avery Drake.
(Follow path to left of stop to reach the grade of the Erie-Lackawanna Railroad. Be extremely careful on the railroad grade, there are occasional trains. Follow railroad grade about 600 feet to west.)
Here are beautiful outcrops of interbedded slate and thin graywacke of the upper Bushkill member of the Martinsburg Formation (see fig. 2). The Ramseyburg Member crops out along the road about 700 feet north of these outcrops. The rock in this outcrop is inverted as shown by sedimentary structures. Fabric elements are: bedding, 50° W. 45° SW.; slaty cleavage, N 70° W, 35° SW.; intersection of bedding and slaty cleavage, 20° S. 35° E., and extension lineation. 28° S. 38° E. Here, the bedding-cleavage intersections which are roughly parallel to the local fold axes plunge southeast beneath the Federal Springs klippe about parallel to the direction of transport as shown by the extension lineations.
Next, the field trip will turn around and follow the railroad tracks to the east. About 400 feet east of the overpass there are horribly mangled outcrops of Bushkill not very far beneath the Federal Springs thrust fault. The field trippers can sort out structures here at their pleasure. The Federal Springs thrust fault crops out about 500 feet farther to the east. The geologic relations at this site are quite complex as it is essentially a quadruple point between Epler Formation, Ontelaunee Formation, Jacksonburg Limestone, and Bushkill Member of the Martinsburg Formation. The Federal Springs thrust fault brings rocks of the Beekmantown Group and Jacksonburg Limestone onto the Bushkill. Two units occur within the Beekmantown here. The lower unit, the Epler Formation consists of very earthy, silty, finely crystalline dolomite that has silty partings, limey dolomite, and some limestone. The Epler is overlain by a unit of medium-gray, medium- to coarsely-crystalline dolomite which based on our experience in Pennsylvania, we assign to the Ontelaunee Formation.
The Jacksonburg Limestone appears to uncomformably overlie both Beekmantown units in these exposures. The Jacksonburg here is a small tectonic sliver of dark gray, shaly cement rock. A sample of this rock contained a poor conodont fauna which, according to John Repetski (written commun., 1979) included the following:
2 drepanodonti form elements, indeterminate, deformed
1 paltodonti form element A
1 paltodonti form element B
Another tectonic sliver of Jacksonburg crops out along the Federal Springs fault about 1100 feet N. 63° E. from this site. The Jacksonburg here is a radically different rock type. being medium-grained calcarenite grainstone. A sample from this site contained as, identified by John Repetski (written commun., 1979) the following conodont fauna:
PANDERODUS
PHRAGMODUS UNDATUS Branson and Mehl
dichognathiform elements
oistodonitform elements
phragmodontiform elements
PLECTODINA
cyrtoniodontiform (N) element
This rather non diagnostic microfauna ranges from the Rocklandian to upper Richmondian. The conodont color alteration index (CAI) of the elements in this sample is 5, indicating host rock temperatures greater than about 290°C.
The structure above the Federal Springs thrust is quite complex. At the end of the railroad cut about 5S0 feet to the east of the fault, Epler crops out at track level. About 65 feet west of this point Ontelaunee is at track level, and about 250 feet farther west Epler comes back down to track level. This rock distribution defines a very tight fold which plunges about 35° N 70° E. Small early folds within this part of the outcrop plunge 35° S 47° E.; essentially parallel to the extension lineation within the Epler. These folds have an S rotation sense when viewed in profile showing that this is an inverted limb. Other fabric elements here include: steep fracture cleavage, due N., N. 80° E.; pressure solution veins which plunge 40° S 20° E., and opens buckle folds in bedding which plunge 10° N 75° E.
Just at the Federal Springs thrust which trends northeast and at these places dips rather steeply, the Jacksonburg Limestone is transposed and the transposition foliation is folded with the rocks of the Beekmantown Group. The fabric elements within the Jacksonburg include: the transposition foliation, N 25° E., 52°NW.; intersection of bedding and slaty cleavage 40° N; 20° W., extension lineation on the transposition foliation, 48° N 40° W.; and axes of small folds in the transportation foliation 10° S 45° W. The lineation formed by the intersection of bedding and cleavage streams around the fold hinge directly above the thrust.
Folds such as those above the thrust are not obvious in the slates of the Bushkill beneath the thrust. The fabric elements in the slate include: bedding, N 75° E 35° NW. (sedimentary structures show that the rock faces up); slaty cleavage. N. 5° W. 35° SW.; fracture cleavage, N. 75° W. 40° SW.; and axes of small folds in slaty cleavage 12° S. 60° W. A wide variety of structures can be observed in the Bushkill to the west of the thrust and the interested observer can observe these at his/her leisure.

More outcrops of Bushkill on right.

Small outcrop of Bushkill on left.

There is a good view of Hunts Pond
There is a good view of Hunts Pond to the right front. We have done no geologic mapping in this area.

Pavement outcrops of Bushkill on the left.

Excellent Bushkill outcrop on the left.

Bushkill outcrop to right, small pond to left.

Bushkill outcrops on the left.

Outcrops of Bushkill on the left.
Here, the slaty cleavage has been rotated past the horizontal and dips northwest. Route 94 is roughly paralleling the geologic strike in this area.

Scattered outcrops of Bushkill along here.
Slaty cleavage dips to the northwest.

Outcrops of Martinsburg Formation on the left

STOP 9: Grand Union klippe
Speaker Avery Drake.
This klippe is a relatively small slab of Allentown dolomite which lies on rocks of the Ramseyburg Member of the Martinsburg Formation. The thrust fault beneath it (fig. 10) was well exposed during excavation for this shopping center. The thrust fault, thought to be the Jenny Jump thrust fault, is roughly parallel to the bedding in the Allentown N. 50° E. 40° NW., and is marked by 1 to 3 inches of gouge as well as by a fair amount of crushed dolomite. The rocks of the klippe face up as is clearly shown by abundant algal stromatolites.
The rocks of the Ramseyburg beneath the thrust are isoclinally folded. The fold trains have a (zigzag) "M" pattern suggesting that the rocks occur in a fold hinge. Bedding immediately adjacent to the thrust is N. 35° E. 65° NW., and it approaches vertical several feet to the southeast (Fig. 10). Slaty cleavage is N. 20° E. 35° NW., has been rotated past the horizontal, and is truncated by the thrust. These data and their geometric relations suggest that the Ramseyburg here is in the brow and upper limb of a northwest-closing recumbent fold. The slaty cleavage is marked by an extension lineation which plunges 39° N 55° W. and extension fractures are N. 38 ° E. 85° SE.
Close examination of the Ramseyburg shows that it, like other Martinsburg we have seen in exposures beneath the Jenny Jump thrust, is an autoclastic melange. Here, most of the graywacke beds have been pulled apart and fragmented and swim as autoclasts in a more slaty matrix.
Two sets of small faults can be seen in the Ramseyburg. One set is
N. 52° E, 40° NW. and has pressure solution veins which show left-separation. The other set is N. 50° E. 80° NW. and shows normal-separations.
This exposure is extremely important as it clearly shows that a klippe of the Jenny Jump thrust sheet was emplaced subsequent to major deformation and slaty cleavage development in rocks of the Martinsburg Formation. This klippe, like the others we have seen, lies in a synform in the slaty cleavage of the Martinsburg.

Large outcrops of Allentown dolomite on right.
This rock is in the Allamuchy nappe.

Good outcrops of Allentown Dolomite on left.

Outcrops of Allentown Dolomite on the right.

Outcrops of Allentown Dolomite behind the Rustic Wine Cellar.

Outcrops of Allentown Dolomite on both sides of road.

Proterozoic rocks at the Allamuchy nappe
Proterozoic rocks at the Allamuchy nappe crop out to the right. The allochthonous nappe-nature of the tectonic unit was confirmed in this area by diamond drilling by the New Jersey Zinc Company (Baum, 1967).

More outcrops of Proterozoic rocks
More outcrops of Proterozoic rocks on the left. We will remain in these rocks until we rejoin Interstate 80.

Outcrops of hornblende granite.
This is Bryam Township, the type area of the so-called Bryam Gneiss.

6: THE NEW JERSEY COASTAL PLAIN
AND ITS RELATIONSHIP WITH THE BALTIMORE CANYON TROUGH
Richard K. Olsson
Rutgers University
New Brunswick, New Jersey
The coastal plain of New Jersey lies along the western edge of the Baltimore Canyon Trough, a large sedimentary basin which extends along the United States Middle Atlantic states (Fig. 1), The Baltimore Canyon Trough extends seaward beneath the continental shelf to the upper continental slope. A westward extension of the trough forms the Salisbury Embayment of New Jersey, Delaware, Maryland and eastern Virginia. The Raritan Embayment of northern New Jersey and Long Island is a shallow embayment. The South Jersey High separates these two embayments of the trough. The Baltimore Canyon Trough is composed of a seaward-thickening wedge of Mesozoic and Cenozoic sedimentary rocks which overlie a warped and faulted crystalline basement. The sediments that lie within the New Jersey Coastal Plain were deposited west of the main hinge line of deposition. Seaward of the hinge line the sedimentary rocks of the Baltimore Canyon Trough thicken to at least 14 km (Poag, 1979). In contrast the maximum thickness of sediments in the New Jersey Coastal Plain is less than 2 km in tHe Salisbury Embayment.
The sediments in the Baltimore Canyon Trough were initially deposited when North America and Africa separated during early Mesozoic time. The sediments (Figs. 2,3) that accumulated in the Baltimore Canyon Trough consist of limestones, sandstones, sands, shales, and clays (Poag, 1979). Diapir structures noted in geophysical profiles (Grow, 1980; Schlee and Grow, 1980) along the continental slope suggest evaporite deposition occurred in the early phases of continental separation. A deeply buried thick sequence of limestone of Jurassic and Early Cretaceous age is identified in multi-channel seismic reflection profiles of the trough and a carbonate bank or reef thought to represent the lower Cretaceous shelf edge is postulated to lie beneath the present day upper continental slope. Limestones of late Jurassic and early Cretaceous age were penetrated in the basal portion of the COST B-3 well which was drilled on the continental slope off New Jersey. The limestone sequence is confined to the deeper portions of the trough and does not extend beneath New Jersey.
Overlying the limestone sequence (Figs. 2,3) are upper Jurassic and lower Cretaceous nonmarine and shallow marine sandstones and shales (Poag, 1979). These sediments thin beneath New Jersey and lie upon crystalline basement rock. Where penetrated in wells they appear to be nonmarine in character although they have not been thoroughly studied. The upper Cretaceous and Tertiary marine sequence that forms the major part of the New Jersey coastal plain belongs to a marine cycle that began during Aptian time and transgressed over the Atlantic margin, bringing sea level over the New Jersey area for the first time since the Atlantic began to open.
The sediments that were deposited in the coastal plain of New Jersey consist of fluvial sands, gravels, and variegated clays; coastal deposits of beach, lagoon, marsh, and related deposits; inner shelf sediments consisting of shore face sands with characteristic Ophiomorpha trace fossil assemblages and offshore micaceous clay and silty thinly bedded fine sands; mid and outer shelf clay glauconite sands and glauconitic clays, often extensively burrowed; and slope deposits composed of calcareous clays and silts. The formations of these various facies were deposited during major cycles of sea level change and are genetically related to sedimentary units that have been penetrated in the COST B-2 and B-3 wells in the Baltimore Canyon Trough. The relationship of the New Jersey formations to the units penetrated in these wells will be discussed in the section on lithologic units.

6: THE NEW JERSEY COASTAL PLAIN
AND ITS RELATIONSHIP WITH THE BALTIMORE CANYON TROUGH

STOP 1. Raritan Formation overlain by the Pensauken Formation (Pleistocene?).
The sands and clays of the Raritan represent continental and coastal marine sediments deposited adjacent to a transgressing sea. The marine facies of the transgression is encountered in coastal plain wells. The subsurface marine unit is called the Bass River Formation.
Pensauken Formation 5-10 feet
dark yellowish-brown sand and gravel. Large scale steeply dipping cross-beds represent slip faces of fluvial bars. Approximately 50 yds. to the west a fining upward sequence is present. Gravel and lithic fragments are present at contact with Raritan Formation.
Raritan Formation (Woodbridge Member) 65 feet
interbedded sand and clay with numerous siderite and iron oxide cemented sand layers. Two directions of planar cross-bedding can be observed. The cross-bedding probably represents sand waves of a meandering stream or of intertidal currents. Marine fossils are present in some of the sand layers. 30-40 feet.
sand and clay containing abundant carbonized wood. 5 feet.
dark-gray clay and silt, sharp contact with overlying unit. Fine bedding (0.5 mm) composed of clay·silt laminations. 20 feet.
Correlation: Plant fossils and palynological remains in the Raritan indicate a Cenomanian to Turonian (Washita to Eagle Ford) age. Marine fossils (planktonic foraminifera) of a similar age occur in the Bass River marine facies in N.J. coastal plain wells.

STOP 2. Magothy Formation overlain by Pleistocene? sediments.
The Magothy represents estuarine sediments deposited in front of the advancing Merchantville sea. This exposure represents an intertidal sequence of tidal delta sands and lagoonal clays.
Pleistocene? 1 1/2 feet
Sand and gravel
Magothy Formation 45 feet
dark gray sands and clays with carbonaceous rich layers, uniformly cross-bedded sands, intermixed flaser bedding and layers of rip-up clasts. 29 feet.
dark gray laminated clay which laterally on the east side of exposure grades into interbedded sands and clays, carbonaceous rich layers. 8 feet.
dark gray alternating sands and clays. 8 feet.
Correlation: Palynological studies indicated that the Magothy is Santonian in age. This suggests that the Coniacian is absent due to disconformity. This is confirmed in the subsurface on the absence of marine assemblages of Coniacian age.

STOP 3. Woodbury, Merchantville, and Magothy Formations.
The Merchantville Formation represents the second major transgression in the Upper Cretaceous sequence of New Jersey. Subsequent transgressions and regressions of the Cretaceous appear to have fluctuated about the Merchantville strandline.
Woodbury Formation 5-10 feet
dark gray micaceous clayey silt
Merchantville Formation 12 feet
dark gray to greenish black, uniformly bedded sandy silt and clay to sandy clay. Glauconite, mica, and siderite are abundant throughout. Many molds of molluscs are present.
Magothy Formation 8 feet
dark gray alternating fine sand, silt, and silty clay. Rare Ophiomorpha burrows.
Correlation: Ammonite species (Scaphites hippocrepis and others) found in the Merchantville in outcrop date this formation as early Campanian (Taylor) in age. In the sub-surface marine assemblages (planktonic foraminifera) of Santonian (Austin) to early Campanian age are present in the Merchantville thus demonstrating its partial equivalence with the Magothy.

STOP 4. Wenonah Formation overlain by Mt. Laurel, Navesink, and Redbank formations.
The base of the section is exposed in the lower excavation and the upper part is exposed in the higher excavation behind the gymnasium
The sedimentary units at this stop and the next were deposited during a regressive-transgressive-regressive cycle. Bedding characteristics and trace fossil morphology position these units in a marine profile of the transgressive-regressive cycle. See fig. for a composite section.
Redbank Formation (Sandy Hook Member) 15 feet
dark gray, very micaceous; argillaceous, feldspathic, fine quartz sand with disrupted sandy laminae and occasional small-scale cross-laminae. Thick-bedded with mottled texture. Contains sand-filled burrow tubes and the trace fossil Zoophycus.
The above features suggest that the Sandy Hook was deposited in an inner shelf environment not far from the shoreface.
Navesink Formation 20 feet
dark gray clayey, silty, glauconite sand. Burrowed mottled. Contact with the overlying Sandy Hook is gradational. The basal 2 feet of the Navesink contains abundant molds of megafossils and rounded pebbles. Megafossils include large bivalves, gastropods, and phragmacones of belemnites.
The Navesink represents the typical glauconitic shelf facies of the Cretaceous of New Jersey. Paleo-bathymetric indicators (various fossil groups and sediment characteristics) suggest deposition under mid-shelf conditions.
Mt. Laurel Formation 27-33 feet
Thin to medium bedded light gray to white fine to medium sand with thin chocolate brown silt and clay layers. The sand is well-sorted, angular, and slightly glauconitic with dark micaceous laminae. Tabular planar cross-bedding is common in the sand beds. The beds range in thickness from 2-3 inches at the base of the section to 4-6 inches at the top. Maximum thickness is 15 inches. Common broad shallow trough cross-bedding suggests shoreward migration of lunate megaripples. The paleocurrent direction is bimodal, being northwest and southeast. The predominate direction is to the northwest (onshore).
The upper 6 feet is bioturbated and consists of a poorly sorted clayey sand and containing rounded pebbles, abraded fossil molds, and glauconite. Glauconite infills burrows in the upper 3 feet.
Vertical cylindrical burrows of the trace fossil Ophiomorpha and cylindrical to rod-shaped burrows of the trace fossil Asterosoma are present in the lower 20 feet of the section. From about 15-20 feet above the base large robust vertical cylindrical and ellipsoidal horizontal burrows of Ophiomorpha predominate. Thalassinoides also occurs within this interval.
The sedimentary characteristics and the trace fossil associations indicate that the lower 10 feet of the Mt. Laurel Sand was deposited in a transitional zone from offshore (innermost shelf) to shoreface (just below the surf zone). The interval from 10-20 feet above the base represents lower shoreface deposition. The uppermost 6 feet of the Mt. Laurel may be a lag deposit related to deposition of the overlying transgressive Navesink.
Wenonah Formation 8 feet
gray clayey, slightly glauconitic, micaceous, fine quartz sand. Burrowed mottled with indistinguishable bedding. Occasional large clay-filled subvertical burrows (Asterosoma) and Zoophycus
The Wenonah represents an inner shelf facies related to a minor regression prior to the Navesink transgression.

STOP 5. Redbank Formation (Sandy Hook and Shrewsbury Members).
The basal part of the section is exposed behind the Ern Construction Co. and the upper part is exposed above and just beyond in a long excavation.
Continuation of the section from Stop 4. It represents regression shoaling after the Navesink transgression.
Redbank Formation (Shrewsbury Member) 25 + feet
Light gray to white, micaceous, feldspathic, mostly well-sorted fine to medium quartz sand. The lower 10 feet is slightly silty. Occasional thin clay horizons define inclined bedding which represents foreset beds of a prograding sand body. Planar cross-stratification occurs within the foreset beds. Both dip south-westward.
The trace fossil assemblage includes vertical cylindrical and horizontal ellipsoidal Ophiomorpha, rod-shaped Asterosoma, and Chondrites.
Redbank Formation (Sandy Hook Member) 15 feet
Dark gray, very micaceous, argillaceous, feldspathic, fine quartz sand. Mottled texture with sand-filled burrow tubes and the trace fossil Zoophycus. The large light-dark mottled shapes are caused by weathering related permeability

STOP 6. Navesink Fm overlain by Redbank Fm (Sandy Hook Member).
Turn right into parking lot just beyond small bridge. Poricy Park fossil beds area. Walk along path to stream bank.
In contrast to the Navesink at Stop 4, at this locality the formation is richly fossiliferous with skeletal material.
Redbank Formation (Sandy Hook Member) 25 feet
Dark gray, micaceous, feldspathic, fine to medium quartz sand. Glauconitic in the basal part which contains microfossils and small megafossils.
Navesink Formation 15 feet
Greenish-black. clayey glauconite sand. Several shell layers are present. The oysters Exogyra, Pycnodonte, and Ostrea; the brachiopod Choristothyris; and the belemnite Belemnitella are well-preserved and common. Molds of various molluscs are common and an extensive well-preserved epibiont bryozoan fauna is present. Microfossils include foraminifera, ostracodes, coccoliths, and dinoflagellates.

Optional STOP. Type locality of the Tinton Formation
Tinton Falls. Turn left and immediately park by restaurant. Walk behind restaurant.
Type locality of the Tinton Formation, the only indurated unit within the Upper Cretaceous section. The formation is very limited in its geographic extent, disappearing within a short distance along strike to the southwest and in a downdip direction.
Tinton formation 22 feet
Brownish green, argillaceous, quartz and glauconite sandstone interbedded with layers and lenses of gray claystone. Molds of megafossils of gastropods and pelecypods are common. Rare specimens of the ammonite Sphenodiscus occur. A well developed dinoflagellate flora is also present.
The Tinton probably represents an inner shelf facies related to the Redbank regressive facies. It is latest Maestrichtian in age.

STOP 7. Manasquan and Shark River Formations
Stop by dirt road on left. Walk along road to riverbank on the right
Manasquan and Shark River Formations overlain by Piney Point (1) and Kirkwood Formations.
A major disconformity is present here wherein the middle and upper Eocene and the lower Oligocene is missing. More of the Eocene and the Oligocene is encountered in the subsurface, however. Marine deposition that began in the late Cretaceous continued in the early Tertiary. It ended during late Eocene time with a large scale regression. The overlying transgressive Piney Point was deposited under inner shelf conditions on an eroded Eocene surface. The basal Kirkwood is probably a shoreward facies of the Piney Point.
Kirkwood Formation 6-7 feet
Chocolate brown clay 5-6 feet
Piney Point Formation ?
Brown, medium to coarse quartz sand 1 foot
Shark River Formation (Squankum Member) 6 feet
Cream to gray brown, argillaceous, glauconite sand. Upper 1-3 feet indurated. Numerous molds of Molluscan megafossils, plus sharks teeth.

7: COASTAL DYNAMICS AND ENVIRONMENTS ON SANDY HOOK, NEW JERSEY
Norbert P. Psuty and Lindsay Nakashima
Center for Coastal and Environmental Studies
Rutgers University
New Brunswick, New Jersey
George Theokritoff
Newark, New Jersey
Sandy Hook is a complex and compound recurved barrier spit located at the northern end of the ocean shoreline of New Jersey (Figure 1). The spit is formed from the northerly transport of beach material derived from the erosion of beaches extending approximately 40 kilometers to the south. The shoreline of Sandy Hook consists of several distinct segments with different rates and forms of development. The spit system may be conveniently broken down for analysis into a set of subsystems, each with differing shoreline orientations to the approach of ocean swell and each experiencing different equilibrium conditions. These subsystems, or beach segments are identified on Figure 1 as numbers 1 through 7. Certain beach subsystems may be further divided into subunits, identified by lower case letters on Figure 1. Each of these experiences slightly different shoreline development. These smaller subunits are strongly affected by man-made beach protection structures. The effect of these structures in producing longshore movement of sediment through the spit system is considerable, as revealed in the conspicuous erosion downdrift of the beach protection structures in Segments 1 and 50
The majority of high energy deep water waves approach the region from the east-northeast and east (Saville, 1954). However, wave refraction on the in-shore portion of the continental shelf causes the shallow water waves to approach from the east-southeast (Fairchild, 1966). This region is also subject to the effects of mid-latitude and tropical cyclones, as well as to ocean swell generated by winds far out in the Atlantic Ocean. On the bayside of the spit, the limiting variables of wind speed, duration, and fetch distance favor wave generation from the northwest. Evidence of the importance of these northwest winds is seen in the orientation of bayside beaches perpendicular to this compass direction and also in micro-spit development to the south of these beaches.
The spit platform, delineated by the 6-foot, 12-foot, and 18-foot contours, is the subaqueous extension of the headland beach upon which the spit ridge (beach and dune system), has formed. The platform extends out a considerable distance on the bayside and has a filtering effect on the higher bayside waves during low tide. This condition is most pronounced when strong northwest winds occur. These winds generate high energy waves and blow water out of the bay. During such periods, spilling waves may occur across the width of the shelf and a considerable amount of material may be moved alongshore within this broad surf zone. However, the presence of deep coves downdrift of Segments 4 and 5 prevents significant transfers of sediment between segments by this mechanism. False Hook Shoal appears to be the seaward extension of the spit platform formed by ebb tidal currents passing the distal portion of the spit. This shoal affects wave refraction and thus controls shoreline orientation and beach development on Segments 2 and 3.
Table 1 reveals the magnitude of beach processes within each of the subsystems. Table 2 identifies the amount of shoreline change which occurred within each segment from 1943 to 1972. The two tables reveal that bayside beaches are retrograding at surprisingly high rates. This is due to a reduction in the quantity of sediment being passed to downdrift segments, and to higher wave steepnesses.
The differences in response to changing wave processes on oceanside and bayside beaches at Sandy Hook have been discussed in detail in Nordstrom (1975). It was concluded that bayside beaches (Segments 4 through 7) appeared to be more in equilibrium with storm conditions than oceanside beaches (Segments 1 through 3). Lower bayside wave energies occurring between storms have little effect on profile development, and foreshore slopes inherited from previous storms undergo minor change. There is little or no deposition between storms. The rate of return is too low to provide adequate protection against dune erosion during the next storm, and dune and foreshore erosion will continue. On the oceanside, in contrast, long, high energy, constructive waves occurring between storms rapidly restore the sediment. These deposits provide a buffer zone to protect the beach and dune against the direct attack of storm waves. The net displacement of the shoreline, therefore, is reduced because of the beach recovery between storm periods.

7: COASTAL DYNAMICS AND ENVIRONMENTS ON SANDY HOOK, NEW JERSEY

Entrance gate to Sandy Hook
Entrance gate to Sandy Hook Unit of Gateway National Recreation Area. Proceed straight (north) on Hartshorne Dr. Segment la. Seawall to the right (east) was constructed at the turn of the century and fronts the narrowest portion of the spit.

Northern terminus of a seawall and groin field
Enter parking lot on right (east) and walk out to seawall. Segment 1a. This represents the northern terminus of a seawall and groin field that extends 8.5 miles (14 km) southward. Beaches in this segment are either non-existent or very narrow. High wave energy, a low littoral drift rate, and excessive downdrift erosion combine to produce a negative sediment budget.

Segment 1b.
At this point the road parallels the most critical zone of erosion on Sandy Hook. The beach here is narrow and forms a log-spiral in plan. Recent beach nourishment and sand bag dike operations have been employed as shore protection measures. Note the absence of dunes and the presence of over-wash deposits on left (west) side of the road.

Segment 1b. Site of bath house
Segment 1b. Site of bath house destroyed by storm activity in February, 1978. Parking lot forms on extensive impervious surface which facilitates back-barrier flooding.

Visitors Center
Turn right (east) into National Park Service Visitors Center parking lot and walk out to beach. Segment lb. Regressive log-spiral shoreline of Segment 1b and offset terminus of seawall in Segment la are evident in a southward view. This Segment experiences cyclic beach response and very high erosion rates (Table 2). Ocean swell and wave-induced currents are dominant processes. Sands on the oceanside are well-sorted and medium size. Beach cusps area frequent occurrence. The site of a second bath house lies 100 yards (30 m) to the north.

South Fishing Beach
Bear right (east) on gravel road to South Fishing Beach. Segment 2a. This Segment primarily responds to waves and wave-driven currents, and experiences relatively high storm and swell energies. Backshore features a natural dune belt. Beach is wider than that found in Segment 1.

Battery Gunnison
Enter gravel parking lot on right (east) at Battery Gunnison and walk to beach. Segment 2b. The nearshore in this Segment is characterized by a longshore bar which shelters the beach under high wave conditions. Cyclic beach response is solely associated with major storms. Ocean waves and wave-driven currents are dominant processes. The entire Segment is backed by a natural dune system. The beach north of the timber groin is used as a beach fill borrow area for nourishment of Segment lb.

Lighthouse to the left
Lighthouse to the left (west) marked the terminus of the spit in the 18th century.

Segment 3.
Turn right (east) on gravel road to North Fishing Beach parking lot and walk to beach, Segment 3. This beach is sheltered by longshore bars and False Hook Shoal. Net deposition-occurs in this Segment which is effected by the complex interaction of waves (ocean and bay) and currents (tidal and wave-induced). The shoreline in this Segment is not straight but displays a concave seaward geometry as one walks northward. The tip of the spit exhibits the highest dunes and an ebb shoal which forms False Hook Shoal. Spit growth occurs to the northwest but is limited by annual dredging of Sandy Hook Ship Channel.

Segment 5a.
At this point a seawall fronting large houses (Officer's Row) is visible. Tidal currents and bayside waves are important processes. Bayside Segments possess shore protection structures and deep coves which inhibit sediment transfers to adjacent Segments. The highest bayside waves are experienced here and Segment 4 to the north. Segment 4 lies under jurisdiction of the U.S. Coast Guard and is a restricted area.

This is the terminus of the seawall in Segment 5.
The formation of a log-spiral beach is occurring immediately to the south of the seawall. This Segment is undergoing the greatest amount of erosion due to locally generated swell and storm waves. A peat bed is exposed on the low tide foreshore and a transgressive sequence is forming over the salt marsh deposit. Sediment eroded from this beach is important to development of a spit farther south.

Segment 6a.
The aforementioned accreting spit can be seen to the right (west) across Horseshoe Cove. Wave activity and tidal currents are less important here than other bayside sites. The beach is extremely thin and erosion is threatening the road adjacent to the seawall.

Segments 6a and 6b.
Limited access parking area. This Segment experiences net erosion. Sediments are continuously eroded from behind the timber bulkhead and a deep cove updrift limits input of sediment. The southern extent of this Segment exhibits a small flood tidal delta formed in a breach at Spermacetti Cove. Sediments in this Segment are primarily coarse sands and lag gravels.

Segment 7.
This permits a view of Plum Island and the Shrewsbury River. As would be expected, the lowest wave energies are encountered here. Plum Island is undergoing erosion with accretion occurring at both ends. Such accretion favors formation of a salt marsh habitat. Coarse sands and lag gravels are present. Much of the sediment composing this island is fill, including the land that connects it to Sandy Hook.

8: LANDSCAPE FEATURES AND BOG IRON ORE DEPOSITS OF THE PINE BARRENS
Emily W. B. Russell
New Brunswick, NJ
Edward Krug
Department of Soils and Crops
Cook College, Rutgers University
The New Jersey Pine Barrens, which include the designated Pinelands National Reserve, are a large, unique combination of ecosystems which in general are coextensive with a Tertiary (Miocene) surficial formation, the Cohansey sand (Fig. 1). They thus represent an area where surficial geology exerts a large effect on vegetation. In this general climatic region the natural vegetation is usually deciduous, primarily oak (Quercus spp.) forest (Braun 1950). However, in the Pine Barrens, the forests have a much larger percentage of pines (Pinus spp., esp. P. rigida), in places even to the exclusion of any tree-size oaks. Minor topographic variation plays an important role on the variability within this ecosystem. Lowland forests, mainly of cedar (Chamaecyparis thyoides), pitch pine (Pinus rigida) or hardwoods (Acer rubrum, Nyssa sylvatica, and Magnolia virginiana), grow where the water table is near the surface, and dwarf pines grow on topographical highs, usually on a slightly different geological substratum, the Beacon Hill formation.

8: LANDSCAPE FEATURES AND BOG IRON ORE DEPOSITS OF THE PINE BARRENS

STOP 1. Pedogenic Bog Iron Formations
Pedogenic Bog Iron Formations Of Pigeon Swamp, South Brunswick.
Unmined bog iron site that shows the relationships of podzol soils, surface water quality, and pedogenic bog iron formation. This is posted private land. Viewing of bog iron is best achieved by walking in the stream itself. The south bank of the stream is disturbed by dredgings (parts of this stream were straightened) and by bedding of long-abandoned dirt roads.

STOP 2. Bog Iron Dump, Mount Holly
The remnants of an iron ore dump still exist under two large trees growing at the edge of the North Branch Rancocas Creek, Iron Works Park, Mount Holly. Both lake and bog ores are in these piles. The ores were presumably used by the Mount Holly Iron Works which was destroyed in 1778 by the British Army and never rebuilt.

STOP 3. Water Quality, Soils, And Topography
Water Quality, Soils, And Topographic Relationships To Pedogenic Bog Iron Formation Of Rancocas State Park, Hainesport.
Soils are extremely acidic, pH approximately 4, but are not podzols, the vegetation is typical of that of the Pine Barrens. Water draining this land is clear, not organic stained or rusty, not participating in significant iron cycling. At low tide the relationship of pedogenic bog iron formation to topography is easily observable. River water is the source of iron, the brown river waters coming from the upstream podzols. Shallow groundwaters of the Pine Barrens (podzol zone) are also brown (and ferruginous). Therefore this site is unique in that pedogenic bog iron is visible on the surface because of tides and formed in an area where there is little doubt that the local groundwaters can not supply iron for deposition. This iron deposit is unusual in that ocherous earth forms both above and below the ironstone layer whereas it usually only forms below. This sandwiching effect is probably due to the tidal variation.

STOP 4. Typical pingo
In the middle of the field on the south side of the road is a typical pingo, a common local land feature. Similar structures with raised edges are formed in areas of permanently frozen soils in the Arctic, by a complex process of thawing, erosion and deposition (Tedrow, 1969). The permanently wet center here prevents cultivation and is thus seen by the brush growing there. Pingos appear to have attracted Indians and frequently have artifacts on their raised edges. They may also account for the existence of small bogs where the ground water table is well below the surface, since they are usually underlain by clay lenses.

STOP 5. Harrisville Pond.
This is the site of an old iron works. Evidence for mining of bog iron ore can be seen along the river. Much of the lowland forest here is pitch pine, with a canopy of almost pure pine. The understory is dense and includes many shrubs of the heath family (Ericaceae), for example sheep laurel (Kalmia angustijolia) and blueberry (Vacdnium spp.). These lowland areas occur often along streams with low levees, the same conditions conducive to the formation of bog iron ore.
The Oswego River here has a drainage area of 64 mi2 and discharge of 18.7 in/yr (Pinelands Commission, Draft· Comprehensive Management Plan, June, 1980).
Just up on the left is an exposed soil profile and upland forest. The canopy here is mainly pitch pine (Pinus rigida) but also includes the typical blackjack oak (Quercus marilandica). Tall shrubs are mainly scrub oak (Q. ilicifolia); other prominent shrubs are black huckleberry (Gaylussacia baccata) and lowbush blueberry (Voccinium vacillans). The litter is thin,and scattered where there have been frequent fires. Sandiness and leaching show in the podzol. Without fire the upper humic horizon would be deeper. Below this is the bleached zone. A zone of accumulation of the leached iron and humic compounds may form below this, just above the parent material or Cohansey sand. In places this yellow sand is brought to the surface and deposited on the white sand by ants.

STOP 6 Oswego Lake (Penn State Forest).
There are two types of swamps in this vicinity, hardwood and cedar. Note the pointed tops of the cedar trees (Chamaecyparis thyoides) compared with the flat tops of the pines. The short gradation between these two indicates the small changes in elevation associated with the change from upland to lowland vegetation. The understory here includes highbush blueberry (Vaccinium corymbosum) and swamp azalea (Rhododendron viscosum). In openings the sphagnum moss mat also includes the tiny plants of cranberry (Vaccinium macrocarpon). Both of these species of Vaccinium are grown here commercially.
In places in the cedar swamp, red maple (Acer rubrum) and black gum (Nyssa sylvatica) form an understory which may eventually replace the cedars. Such an area of hardwood swamp can be seen shortly downstream from Oswego Lake. The red maple and black gum are here accompanied by sweet bay (Magnolia virginilma). Continue on past the lake.

STOP 7. Pine Plains
These dwarf forests are the most distinctive feature of the Pine Barrens. There are no other such forests approaching the areal extent of these elsewhere in the world. Stunted, many-trunked blackjack oak and pitch pine dominate the low canopy. Broom crowberry (Corema conradil), a species which reaches its southern geographical limit in the Pine Barrens, is found here. It is a species which probably migrated south along the exposed coastal area during the Pleistocene and has since been isolated from northern populations by the rise in sea level. Note also that the soil here is coarser than in the other upland site, a characteristic of the Pine Plains which may increase dryness and thus fire frequency.

STOP 8. Oyster Creek rest area.
Oyster Creek with 7.43 mi2 of drainage area has a flow of 51.4 in/yr. Compare this with the values for Oswego River. This difference is caused by interbasin transfer of ground water. Much of the water that falls in the Oswego River watershed soaks quickly down into the aquifer below the bed of the river and flows past it, to come to the surface eventually in such streams as Oyster Creek.

9: LATE WISCONSIN-HOLOCENE HISTORY OF
THE LOWER HUDSON REGION:
NEW EVIDENCE FROM THE HACKENSACK
AND HUDSON RIVER VALLEYS
Stephen P. Averill
Fairleigh-Dickinson University
Rutherford, N.J.
Pascack Valley Regional High School District
Montvale, New Jersey
Richard R. Pardi and Walter S. Newman,
Radiocarbon Laboratory
Department of Earth and Environmental Sciences
Queens College, City University of New York
Flushing, New York.
Robert J. Dineen
New York State Geological Survey, Museum
Science Service State Education Department
The study area (Fig. 1) is the central and upper Hackensack River valley of northeastern New Jersey and adjacent New York State with reconnaissance study of the surrounding area in Bergen County, N.J. and Rockland County, N.Y. In the text, town names will be in New Jersey unless indicated otherwise. Geologically, the area is the northern portion of the Trias-Jurassic Newark basin where a gently dipping (14°W) homoclinal sequence of Brunswick Formation red sandstones and shales form the deeply scarred bedrock surface. The Palisade sill and basalt lava flows of the Watchungs, interbedded with the Newark series sediments, form prominent topographic ridges in the region. The western slope of the Palisade sill, whose well-studied eastern escarpment forms the Hudson Palisades, is at the eastern margin of the Hackensack Valley. Resistant sandstones of the Newark group form the ridges and cliffs along its western border as well as the divide between it and the parallel drainage system of the Saddle River. The Ramapo fault system slices northeast at the northern terminus of the basin separating it from the rugged Precambrian crystalline mass of the Ramapo Mountain portion of the Appalachian chain. The Hudson River and glaciation have carved an impressive gorge through the Hudson Highlands, The Ramapo River lies in a similar but less spectacular gorge ten miles to the west at Suffern, N.Y. Continental glaciations overdeepened both gorges before overwhelming the Ramapos to push south to their maxima. The deep preglacial Hackensack Valley has been partially overdeepened by glacial ice, then mostly filled by pro-glacial lake sediments (Lovegreen, 1974). The present terrain is gently rolling, with drumlinoidal hills generally aligned north to south paralleling the strike of the bedrock. Essentially glaciation has subdued the preexisting topography, even occasionally reversing it.

We are crossing the Secaucus drumlin.
It is aligned with its long axis N-S. A relatively thin red till overlies this red and gray rock-cored drumlin. Contact metamorphism of the sandstone was observed throughout most of a very large excavation. The Palisade Sill cannot be far below.

Old Lake Hackensack floor
We are crossing the old Lake Hackensack floor now covered by a 3 to 6 meter sheet of sand with the tidal marsh over the sand. The lake covered the "Meadowlands" as far as one can see. The ridges to the east and west formed the shores.

STOP 1. This is the Rutherford rock-cored drumlin.
The Upper Triassic Brunswick formation sandstones and shales are exposed here at the side of the drumlin. Note the copper mineralization. Red drift, sometimes till, sometimes sand and gravel, blanket the drumlin. Some yellow "loam'" may be exposed (if we're lucky). The "loam" here is about 15'cm thick and is loess. This drumlin was at the western edge of Lk. Hackensack.

Proceeding onto the old lake bed surface.
We are leaving the drumlin and proceeding onto the old lake bed surface. As you drive north on Rt. 17, note what was the steep western shoreline of the lake. A deep preglacial valley exists under Rt. 17. The varves are by far the thickest here along the western side of the Hackensack Valley (Lovegreen, 1974).

Reeds' clay pits for 2550 varves
At the center of the valley close to the Hackensack River are the former brick yard clay pits from which Reeds' extracted and counted 2550 varves.

Sandstone ridge
We are now crossing one of the sandstone ridges that form the low divide between the Hackensack and Passaic valleys.

Near distal end of outwash fan
We have just passed through the divide between the Hackensack and Saddle Rivers and are near the distal end of the outwash fan associated with the Ridgewood kame group. As we proceed north on Rt. 17, notice the slope of the outwash plain.

Northern-most of Lake Hackensack red varves
This is the northern-most known location of Lake Hackensack red varves in the Saddle River valley. (G.S. Pkwy boring records.)

STOP 2. Mastodon display and rest stop.

STOP 3. Crest of the Ridgewood kame group.
Walk back to kame. South side of kame shows stratified drift. This used to be a gravel pit. We are told that much coarser gravel was removed from here than is presently exposed. Return to north side of kame. Clean off the face and note the vertical sand layers with minor asymmetrical folds. At the top of the exposure is a layer of fine to medium sand capped with yellow loess under the top soil and vegetation. Return to bus. <br

STOP 4. Musquapsink Brook
Exposure of red till in the banks to the south. Bedrock in stream to the north.

STOP 5. Woodcliff Lake kame delta
We will have to walk along the causeway. Please watch the traffic. This is the Woodcliff Lake kame delta that built into the proglacial lake in the Musquapsink Valley. Note the very sharp drop in elevation below the dam.

Till capping outwash on the island
As we ride, note the till capping outwash on the island in the lake. It forms a small dark slightly overhanging layer at the top.

STOP 6. Woodcliff Lake reservoir
Enter the Woodcliff Lake reservoir of the Hackensack Water Co. NO TRASH DROPS PLEASE. We will examine the wave-cut cliff exposure of yellow-brown till over readvance outwash. There is less than 1 meter of till here. One-tenth of a mile west, immediately west of Pascack Rd., the tightly packed red cobble till of the Lake Hackensack glaciation lies below the readvance outwash.

STOP 7. Atkins Glen Park
This lovely glen is a preglacial valley (at least pre-Woodfordian) cut across the Brunswick fm. strata at right angles to the bedrock strike. This valley contains red till and near the top is overlain by the yellow-brown till. It is very close to the farthest north natural exposure of the red till. The valley was exhumed in post-glacial time when a large and deep lake left by the ice, in what is now the Bear Swamp section (Park Ridge 7 1/2 minute Quadrangle), was drained by downcutting.

We have crossed into the Saddle River basin.

STOP 8. Side of a Drumlin
Turn RIGHT into gravel surfaced area of pit. It is across the street from the Cemetery of the Ascension. The exposure is in the side of a drumlin. The yellow-brown till is well exposed here. A strong bimodal till fabric can be measured here and fissility of the till was noted in two steep-faced exposures.

STOP 9. The River Vale Road drumlin
The Yellow-Brown till is 2.7-4 meters thick here. Red till is below. View to the east (over golf course) is the line of River Vale kames that form a north-south ridge to the east of River Vale Rd. until they join the Old Tappan moraine at their southern end. The west slope of the Palisades is across the Hackensack Valley in the distance.

Kettle bog areas
We travel through some kettle bog areas before reaching the old (landscaped) kame crest line. The Old Tappan moraine is ahead of us (south). The present reservoir is the location of post-glacial Lake Tappan. Note the ice-pressed terrain on the back-side of the moraine dam. Many large kames were removed from here during construction of the reservoir. Ultimate drainage, resulting in that catastrophic flood, was through the present Hackensack River drainage exit at the dam.

Steep-sided kettle
As we drive up the back slope of the moraine ridge, we can see a steep-sided kettle to the left of the road and just north of the small cemetery.

STOP 10. Old Tappan Rd. and Ledson Parkway
Old Tappan Rd. and Ledson Parkway are on the sandy outwash plain. Erosion has cut a gully here and has revealed the yellow-brown till of the moraine at the base of the ravine.

STOP 11, Observe excavated end of moraine.
It is mostly stratified drift here.

STOP 12. Outwash capped by Tappan till
This is a great sequence of outwash capped by a thin layer of yellow-brown Tappan till. The owner has suddenly died and at this writing we are not sure whether we will be able to enter legally.

STOP 13. Tallman Mt. State Park. Lunch.
After lunch Dineen will discuss the geology of the adjacent Sparkill Gap. Averill will discuss the importance of the Gap to the Woodfordian history of the Hackensack Valley. Newman will discuss the origin of the Piermont salt marsh below and the rise of sea level. For the uninitiated, Dineen and Newman will demonstrate their seismic and coring procedures.

Norwood kame grouping
Road begins to increase in elevation at the Norwood kame grouping and generally runs along the crest.

Norwood kames history
The Norwood kames were constructed into glacial Lake Hackensack and were later buried by the readvance Tappan till glacier.

STOP 14. Kame
Enter new development on north side of road. Walk up hill to top.
Kame is constructed of red coarse cobble outwash and has patches of overlying yellow-brown till.

Outwash plain, then erosional slope
The first slope is the outwash plain. There is then a break in the slope and the slope increases. This is the erosional slope first cut during the drainage of glacial Lake Hackensack.

STOP 15. Mastodon site
This is the Norwood portion of the Oradell Reservoir. This is where the mastodon remains were found. The large (3 meter) diabase boulder can be seen. Discussion....

You are on the outwash plain of the Old Tappan moraine.

Ascending the River Vale collapsed moraine outwash plain.

Incised Pascack Brook to left
Note the flood plain of Pascack Brook to the left (West). It cut deeply into the outwash plain south of the Hillsdale heads-of-outwash.

Going down hill into the area of collapsed moraine.
We have crossed Cleveland Ave. head-of-outwash and are going down hill into the area of collapsed moraine. At the end of Cedar Lane at the "T". is a new Condominium complex. These five story pre-cast concrete structures were built directly on glacial Lake Hackensack red varves. No pre-construction preparation was necessary as they (the varves) were already in a pre-consolidated state.

Crevasse channel outwash feeder
The 1st street on the right (Ruckman Ave.) is the crevasse channel outwash feeder. It can be seen on the left (south) across from Ruckman Ave. It is composed of medium clean sand with occasional large boulders. Piermont Rd. cuts through the crevasse filling in a small stream valley (more on that later).

Everdell Ave. along the crevasse filling.

Kinderkamack Road drumlin
We proceed down the hill to the flat valley floor. Ahead of us is the Kinderkamack Rd. drumlin, one of the largest in the area.

STOP 16. Beechwood Park, Hillsdale, N.J.
Walk into park. Note the kame on the west and the large kettle bog. The bog is also found south of Hillsdale Ave. beyond the confines of the Park. B.P.1 boring was made on the southeast side of the bog and penetrated to the bedrock floor of a deep valley 55 ft. down. Surface elevation of the bog is 50 ft. ASL. B.P.2 was sited 10 m south of Hillsdale Ave. almost due south of B.P.1. B.P.3 was sited east of B.P.2 just east of the sewer cut in the deepest part of the kettle.
Note the stratigraphy as shown in Fig. 10. Discussion.
The Hillsdale head-of-outwash is immediately south of us. A small, apparently very short-lived, proglacial lake formed behind the dam and between the drumlin on the west and the crevasse filling on the east. As the ice retreated, the eastern ridge was breached at Piermont Rd.

Proceed south on the outwash plain of the Hillsdale heads-of-outwash.

The first valley we cross is the Pascack Brook.

Large valley drained by Musquapsink Brook
Farther south, after we pass through "5 Corners" in Westwood, we drop into a very large valley drained by the now tiny Musquapsink Brook. This is the valley cut by the draining of proglacial Lake Musquapsink. The Woodcliff Lake kame delta was constructed into this lake.

Proceeding south in Emerson we are still on the outwash plain.

Oradell drumlin
In Oradell, near the Xerox building, more of the same but on the west is the large Oradell drumlin; rock-cored and coated with red till. Lake Hackensack red varves were encountered at the Xerox site under the outwash sand. Yellow "loam" loess as much as 30 cm thick overlies the area to the south. Man's activity has removed much of the loess.

10: ECONOMIC GEOLOGY:
NEW JERSEY HIGHLANDS
General Introduction and Road Log
Andreas H. Vassiliou
Newark, New Jersey
The New Jersey Highlands province comprises the centermost portion of northern New Jersey, extending 96 Km northeasterly across the state and ranging in width from 16 to 40 Km. It is flanked on the northern side by the Valley and Ridge province and on the southern side by the Triassic Lowlands of the Piedmont province. The province, which is part of the Reading Prong of the New Jersey Highlands is essentially a belt of Precambrian crystalline rocks with certain narrow belts of folded and in-faulted Paleozoic sedimentary rocks. The three articles that follow this general introduction contain specific information on these rock types and their relationships.
The Precambrian rocks of the New Jersey Highlands have been hosts to several commercial mineral deposits. Historically, the magnetite iron ore deposits are of unique importance. These deposits have been mined since at least as early as 1710 (Buddington, 1957), perhaps the oldest iron mining in the United States. Geologic and other information concerning the major magnetite deposits of the Highlands was first outlined by Bayley (1910). For several years during the third quarter of the nineteenth century, New Jersey was the biggest producer of iron ore in the United States. Of the 136 mines active in 1880, none are operating today, However, some of the now abandoned mines are still accessible. During this field trip, John Puffer will lead us through two such mines: the Andover-Sulphur Hill Iron Mines (STOP 2) and the Edison Magnetite Deposits (STOP 3).
Interest in the mineralization of the Franklin area has been worldwide and has continued, unabated, for more than a century. In certain rare cases, a significant accumulation of a wide variety of elements is possible in certain areas of the earth's crust, resulting in the formation of a large number of minerals, some of which are unique or exclusive to the area. Kostov (1968) lists only four such localities in the world, with the Franklin area being one of them. The Franklin deposits are enriched mainly in manganese, iron, and zinc, but the combination of the silicate-oxide ore minerals with numerous associated gangue minerals is unique and generally unknown elsewhere. Kushner (1970) compiled an abbreviated manual of Franklin minerals and listed about 200 species. Some of these minerals (e.g., franklinite, zincite, etc.) are either unique to Franklin or are rarely found elsewhere. Today, except for the mining operations at Sterling Hill and at the Farber White Limestone Quarry on Cork Hill Road, all of the mining activities at Franklin have ceased. Bob Metsger, who has been the chief geologist at the Sterling Hill Mine for several years, will lead us through the mine area and describe the occurrence and origin of this classic deposit (STOP 4). Mineral connecting will be available at the mine dump. However, those who are interested may also visit the Trotter and Buckwheat dumps for additional mineral collecting upon payment of a small fee.
The search for uranium in the 1950's is responsible for the greatest metal hunt in the history of the world. The New Jersey Highlands province was included in this hunt, and in 1955 a series of geiger counter hot spots were discovered along the perimeter of a large pegmatite near Cranberry Lake by Mr. Edward Koral and the New Jersey Geological Survey. In 1959 the Byram Exploration Minerals Company put down a vertical shaft on one of the hot spots and named the deposit the Bemco Mine. Throughout the summer of 1959 some uranium was recovered and shipped out (about 95 tons of ore), but the rare earth values of the ore were overlooked at the time. The Bemco Mine, also known as the Charlotte Mine, is located on land now designated as Green Acres and is, of course, inactive. The ore represents a highly unusual mineral assemblage of metamict minerals (e.g. fergusonite, uranothorite, zircon), and is of interest as a good example of hydrothermal mineralization relating to the intrusion of a pegmatite into the metamorphic host rocks. Diamond drill cores studied by Williams (1967) define the ore zone up to a depth of 30 meters. On STOP 1 of the trip, this writer will point out the relationships between the ore and the associated rock units and discuss the origin of the deposit.

10: ECONOMIC GEOLOGY:

STOP 1. Bemco Mine
Led by A. H. Vassiliou
(about one hour). At this point the dirt road has small parking area on the right whose path or trail (uphill) leads to the BEMCO MINE. Go 420 feet along the trail: "sulfide quarry" to the right, downhill. + 840 feet to "red flag" -turn right down the hill to lower trail (about 50 feet).
+ 350 feet, turn left for mine area.
+ 145 feet, to old shaft.
See attached article on the deposit by A.H. Vassiliou.

STOP 2: Andover-Sulphur Hill Iron Mines
Led by J.H. Puffer
(about one hour). Park off road and follow path or trail (right side of road) to ANDOVER-SULPHUR HILL IRON MINES. See attached article by J.H. Puffer.
You will be asked to sign a waiver before entering the mine property, and are requested to wear a hard hat and safety glasses. Follow the path from the mine gate to an open clearing. The Andover Mine workings including adit portals and an open pit are found along a cliff located south of the central clearing. Highly altered diabase dikes are intruded along the cliff. The diabase is black to dark green, highly chloritized, fine grained rock that has been sheared and mylonitized. The magnetite ore is disseminated in a light gray Quartz-Oligoclase Gneiss. Dark green pyroxene-feldspar gneiss is exposed above the cliff east of the mine. The pyroxene-feldspar gneiss is green (highly epidotized) fine grained, migmatitic, locally calcareous rock. The pyroxene component is diopside. A light buff microcline granite gneiss is exposed along the road just west of the mine.
The Sulphur Hill open pit is located about 400 feet north of the central clearing. The pits are dangerous and are closed to visitors. Most of the rocks found in dumps at the north and eastern edges of the clearing are from the Sulphur Hill Mine. The rock is a magnetite and sulphide rich garnet skarn. Amphibolite is exposed south of the Sulphur Hill Mine. It is recognized by its black hornblende content, and is coarser grained than the pyroxene-feldspar gneiss.

STOP 3: Edison Magnetite Deposit
Led by J.H. Puffer
(about 30 minutes). Park off road (clear area on right). Climb up bank, cross fence, to the EDISON MINE magnetite deposit. See attached article by J. H. Puffer.
Buses will turn around. At the southern end of the open pit (The Old Ogden Mine) there are good exposures of a biotite, sillimanite and magnetite rich phase of a metasedimentary Quartz-Potassium Feldspar Gneiss. Sulfides including pyrite, chalcopyrite, and molybdenite are disseminated throughout the rock but are found concentrated near the south-east corner of the pit. Acid solutions leached through the sulfides have accelerated the alteration of the rock to a sericite rich saprolite. Please exercise extreme caution when approaching the open pit, and be on the alert for poison ivy.

STOP 4. The Sterling Hill Mine, Ogdensburg
Led by R. Metsger.
Here we shall have lunch, go on a mine tour, and then do some mineral collecting at the dump. See attached article on the deposit by R. Metsger.

11: ENVIRONMENTAL GEOLOGY OF THE HACKENSACK MEADOWLANDS
Sam L. Agron
This trip to the Hackensack Meadowlands District has several purposes:
1. To observe the natural environment of the Meadowlands, the problems and challenges it poses, and to gain some understanding of how the geologic history gave rise to that environment.
2. To see how numerous, complex, diverse, and seemingly incompatible land uses can be carried out harmoniously and profitably if a region's geology and ecology are adequately understood by planners; and if imaginative engineering, political and economic planning are applied.
3. To inspect several of the major projects that have been erected in the Meadowlands, consider their operational processes and how they impact on the environment and, above all, how geologic constraints were dealt with in designing foundations, etc.
The pioneering work done by the Hackensack Meadowlands Development Commission in planning and overseeing the harmonious growth of the District is unique in this country. A long-blighted area, where land was almost worthless some four decades ago, now contains some of the most valuable acreage in the country. What can be learned here may very well have application elsewhere.

11: ENVIRONMENTAL GEOLOGY OF THE HACKENSACK MEADOWLANDS

West margin of Hackensack Meadowlands.
Schuyler Avenue which follows bluff marking west margin of Hackensack Meadowlands.

STOP 1. (Kearny) Overlook, south end of the Meadowlands.
Panorama (left to right) shows sanitary landfills, more than 100 feet in elevation, over which the first section of the De Korte State Park will be erected; the New York City skyline including the World Trade Center towers (about 7 miles distant); Snake Hill; New Jersey Turnpike; Pulaski Skyway (Routes 1 and 9); and the Bayonne Bridge arch to Staten Island. The southern boundary of the Hackensack Meadowlands District, which is under the jurisdiction of the Hackensack Meadowlands Development Commission, lies about 1/2 mile north of the Pulaski Skyway. The meadowland environment continues south of the District boundary.

Belleville Turnpike descends into Meadow lands.

STOP 2. Tour of HMDC Solid Waste Baling Facility
See text above.

STOP 3. (North Arlington) Schuyler copper mine.
This is the approximate location of the Schuyler copper mine. The shaft was a couple of hundred feet to the NW. The mine was discovered about 1719 and was probably the first copper mine in the United States. It shipped 110 casks of ore from New York in 1721 (Lewis, 1907). Much detailed historical information can be found in Woodward (1944).
The mine was a source of considerable wealth before the Revolutionary War and continued to be worked intermittently until 1865. The primary ore mineral, chalcocite, occurs in unaltered gray arkosic sandstone overlain by red shale and intruded by small, irregular basalt dikes. The major secondary mineral is the bluish-green copper silicate chrysocolla which penetrates the rock along joints and bedding planes.

STOP 4. Panorama of the Meadowlands
Fig. 20 Looking E from Schuyler Ave. (near Carrie Rd.), North Arlington to wetlands in Lyndhurst, N.J. Kingsland Creek, in middle, flows towards the Hackensack River. To the right are landfills and the Sawmill Creek Wildlife Management area.
Overlook showing a panorama of the Meadowlands N of the one in Stop 1. Kingsland Creek, in the foreground (Fig. 20), lies towards the N end of the Sawmill Creek Wildlife Management Area (Fig. 13). The panorama from left to right shows the Meadowlands Racetrack, Giants Stadium, and the Arena; sanitary landfill; twin towers at S end of the Harmon Cove development; Empire State building and mid-town Manhattan skyline behind the Palisades ridge, sanitary landfill, World Trade Center towers are almost in line with Kingsland Creek. The W spur of the N. J . Turnpike is in the middle distance; the E spur passes behind Snake Hill, at the right. Note the wetland dikes.

Descend to Meadowlands.

Copper mine exploration shafts
Bricked-up entrance to copper mine exploration shafts in red beds behind Kuttner Prints plant on left. This is the Lyndhurst Office Industrial Park, one of 11 industrial parks in the Meadowlands. This park includes the Meadowlands Corporate Center and tenants such as Peugeot, Citroen, etc.

Polito Ave. has developed a "wash board" effect
Polito Ave. has developed a "wash board" effect because the road was built directly on the meadow mat, which doesn't support the heavy truck traffic very well.

Cross Berry's Creek.
The very serious mercury pollution problem in Berry's Creek and its environs originated in an industrial plant about 3 miles upstream (see text above). The Creek forms the W boundary of the Meadowlands Sports Complex. whose three major structure loom large on the left.

STOP 5. Meadowlands Sports Complex
(Note: Mileage and routing directions to parking site will be made available by the Sports Authority at time of the trip).

STOP 6. Sewage Treatment Plant
Tour of the plant and new construction in progress. See text above. Opposite this stop, across the Hackensack River in Ridgefield Park, is the Bergen generating station of Public Service Electric and Gas Company (Fig. 21). This plant is in the extreme northeast corner of the Hackensack Meadowlands District. It is a conventional oil-burning power plant, but is also equipped to use coal and natural gas. In 1983 it will also burn garbage from the resource recovery plant to be constructed adjacent to it by Bergen County (Boyd, 1980d). Procedures are employed to minimize thermal pollution of the Hackensack River, to condense spent steam from the turbines for reuse in the boiler.
Several ponds to the northwest of the Sewage treatment plant were clay pits. Little Falls was once the center of a major brick-manufacturing industry.

Two LNG storage tanks to the east

STOP 7. Stone pier S of Sky Harbor Marina
Walk to end of pier for view of Hackensack River (Fig, 22). Sand and gravel storage facility can be seen on opposite (E) shore of the river. in Secaucus. Route 3 bridges cross the river to south. Behind bridge is the Harmon Cove development, our next stop.
Two LNG storage tanks can be seen about 0.7 mile to the NE very close to a superhighway (Fig. 23). Most of the area between here and the tanks has been rezoned for residential use. See text above.

Bridge crossing Hackensack River.
Harmon Cove development on the right.

STOP 8. Harmon Cove Development
Harmon Cove Deve!opment, Hartz Mountain Industries. Secaucus. See text above.
We will leave the bus here and board it at the Twin Towers high-rise condominium at the south end of the development. Start walking along the bicycle and jogging path that winds southward through the area of town houses that stand between Meadowlands Parkway and the Hackensack River (Fig. 24). The top of the 25-story Twin Towers affords a spectacular view of the entire Hackensack Meadowlands District lying on the floor of post-glacial Lake Hackensack. The Manhattan skyline looms impressively beyond the back slope of the Palisades, which marks the eastern border of the District. The Hackensack River can be seen as the central artery sustaining the watery ebb and flow of estuarine life in the wetland habitat. The network of highways includes the Pulaski Skyway, East and West Spurs of the New Jersey Turnpike, Rte. 3, and others. Five highway bridges and six railroad bridges cross the Hackensack River in the District. Landfills towards the SW mark the site of the De Korte State Park. To the north can be seen the Sports Complex, the LNG storage tanks and the PSE & G electric generating plant. Another power plant is at the far south end of the area. Several industrial parks are distributed throughout the District.

Secaucus water tower on right.
The town of Secaucus forms two "islands" inside the Hackensack Meadowlands District (Fig. 6). Its location was determined by the presence of bedrock at the surface, which posed none of the foundation problems found elsewhere in the Meadowlands.

Little Snake Hill on left.

Snake Hill (Big Laurel Hill) on right.
These are diabase plugs which may have served as vents or feeders for the Watchung lava flows. Snake Hill has been largely quarried out for trap rock crushed for use as road metal. It supplied crushed stone for Hartz Mountain Industries. Snake Hill is zoned for residential use (Fig. 4). Because the basalt provides an excellent foundation housing can be built more cheaply here than at Harmon Cove or elsewhere in the District where costly pilings must be used. Low-cost housing has been suggested for the site because the cost per unit would be lower. The site's isolation, however, mitigates against this type of housing.

Sawmill Creek Wildlife Management Area
Sawmill Creek Wildlife Management Area to the right (Fig. 2). This will be part of the De Korte State Park.

12: ENVIRONMENTAL GEOLOGIC TRAVERSE
JOSEPH A. FISCHER
Fees Geosciences Inc., Meyersville, New Jersey
GENERAL CONCEPT
Initially, this trip was going to include a number of stops in the Appalachian Fold Belt, the Highlands, the Newark Basin, the Coastal Plain and right down to New Jersey's barrier beaches. As the detailed plans began to take form, there appeared to be no way to sample in one day, all the varieties of geology that New Jersey has to offer unless one did it from a speeding helicopter. Thus, the route shown on Figure 1 attempts to sample as many different geological environments and concurrent geologic problems as can be "shoved" into a single field trip.
A total of 10 stops are planned (as shown on Figure 1). These are:
1. Route 280 West Orange, road cuts in the First and Second Watchungs;
2. Ridgedale Avenue, Morristown, terminal moraine -- semi-abandoned quarry;
3. Route 202 South of Morristown, Ramapo Fault, hospital across "active" fault;
4. Great Swamp, problems of managing 6,000 acres of wildlife preserve in a suburban environment and how the refuge affects its surroundings;
5. Millington Gorge -- faulted (or erosional) cut through Second Watchung, flooding concerns;
6. Millington Quarry -- blasting and transportation of trap rock in a middle class suburban environment;
7. Bridgewater Township-Route 78 road "cuts" in Second Watchung Mountain, compare with Stop 1;
8. Far Hills -- -Where does the Ramapo go?
9. Bernards Township/Bedminster, proposed 1,500 acre development, variable soil and rock, mostly impermeable soils, mostly shallow rock -- how do you build a new "town"?;
10 . Berkeley Heights -- Whither goest Route 78?

STOP 1. First Watchung
Rather than a stop, this will be a slow drive by (either by direction or limitations of the bus). As the elevation rises from the Northfield Road (State Route 508) intersection with Route 280, the first outcrops seen are of the Brunswick Formation (sandstones). Then Route 280 climbs into a major road cut within the Watchung basalts (First Watchung). The basalt cut is steep and the blocky, columnar structure of the lower basalt can be observed early. At higher elevations, the cut is in ropey and pillow lava. Along the cut in the Second Watchung, while it is still at a high angle, several failures can be observed along minor shear zones in columnar basalt. (see Manspeizer, and Olsen this fieldbook).

Second Watchung
Note Riker Hill to the west as 280W descends to the area of Glacial Lake Passaic . Along the cut in the Second Watchung, while it is still at a high angle, several failures can be observed along minor shear zones in columnar basalt. (see Manspeizer, and Olsen this fieldbook).

Glacial Lake Passaic

New Jersey Highlands to the west
Traversing glacial deposits overlying Brunswick Formation.

STOP 2. Abandoned Quarry
This is a semi-abandoned quarry. The main purpose is to observe the materials in the terminal moraine at this point. At this location, the embankment is primarily sand.

STOP 3. Morristown Memorial Hospital - On Ramapo Fault
Ramapo Fault - Highlands immediately west of road
Is it or isn't it an active fault? If it is active, how active?
Lamont-Doherty Geologic Observatory has indicated it is a capable* fault. The technical and judicial examiners on the recent (1977) Indian Point Nuclear Power Plant Appeal Board hearings declared it was not. The Nuclear Regulatory Commission and Consolidated Edison Co. consultants agree with the hearing board.
Controversy still rages with the planning of two water supply dams across the fault in southern Rockland County. Intervenor witnesses have quoted an April 1978 Science article (see References) concerning the Indian Point plants as their rationale for requesting a seismic factor even greater than that used in design of the nuclear plants across the Hudson River.
Yet here in New Jersey, there are hospitals and schools built across the fault in two towns we will pass through on this field trip -- Morristown and Bernardsville. No controversy seems to exist in this area of the state concerning the activity of the Ramapo, despite experiencing a Mag. 3.1 earthquake in Bernardsville as recently as March 10, 1979,
At this stop we'll quickly look at the "fault" as it passes below a hospital. Is it disaster waiting to happen or is it a tempest-in-a-teapot? Look at the trace here in Morristown. The trip will pass over the Ramapo and related structures several times. The seismicity of the Ramapo will be discussed at Stop 4 (in greater comfort).
* 10CFR 100 Appendix A, Seismic and Geologic Siting Criteria for Nuclear Power Plants.

Route 202 generally lies along Ramapo Fault.
Notice new construction, homes, apartments, office buildings. Some are on septic systems; some are on Morristown sewage treatment plant system.

Descend to Glacial Lake Passaic terrain
Outlier of Third Watchung basalt flow to the north and Long Hill (third flow) to south.

STOP 4. Great Swamp Refuge (lunch)
The Great Swamp Refuge was established in 1960. It is only 26 miles west of New YorK City in the Boston-Washington metropolitan corridor. It is approximately 6,000 acres of swamp woodland, hardwood ridges, grass lands, old croplands, and water impoundments. As previously noted, it is within a portion of the area covered by ancient Lake Passaic.
Approximately two thirds of the refuge is designated as Wilderness Area and the remainder as Management Area. Man-made structures and motorized vehicles and equipment are prohibited by law from this area. In the Management Area, the habitat is controlled by cutting brush and timber, mowing, farming, planting shrubs, regulating water levels, and by providing nesting structures.
The problems of maintaining a wildlife refuge in an area where population and commerce are steadily growing will be discussed by members of the Refuge staff.

Rise from Glacial Lake to Long Hill basalts

STOP 5. Millington Gorge (gorge in basalt)
This steep-sided cut through Long Hill (the Third Watchung) is aligned with Osborne Pond in Basking Ridge and Mt. Kemble Lake in Harding Township as well as a valley through a ring of basalt in the New Vernon area. Is this an en-echelon fault of the main branch of the Ramapo or just differential erosion and coincidence?
Whatever the reason, during heavy storms the Gorge acts as a constraint to flow in the Passaic ponding water as far upstream as the Great Swamp and contributing to many flooded basements to the north (see Figure 1) along Black Brook and the Passaic River.

STOP 6. Millington Quarry (quarry in basalt)
At the time of preparing this outline, it was not known whether we would be allowed within the Quarry or would have to walk from Millington Gorge to view the scope of the operation. The concern here is not the mere idea of quarrying the Watchung basalts, which are well exposed in the Gorge and many other locations for inspection, but in blasting rock and the resulting transportation in a middle-class, suburban environment. The quarry has continually been in litigation with the town because of the noise, dust and shaking caused by trucking and blasting operations.
Present New Jersey State law requires that a peak particle velocity of two inches per second should not be exceeded in critical areas away from any blasting. Whenever checked, the quarry has not exceeded these limits yet the complaints continue, not unexpected as the human body is an excellent vibration device, The present N.J. criteria were derived from work undertaken in the 1960's by the U.S. Bureau of Mines with subsequent confirmation (?) by others in Sweden, Canada and Great Britain. The presently proposed Bureau of Mines criterion is a particle velocity of one inch per second. What will these criteria do to quarries like this and others in similar environment? The proposed criteria also establish air blast limitations.
We'll discuss all of the above.

Shallow Brunswick

Shallow Brunswick to basalts, Second Watchung

STOP 7. Scenic View Parking Area on Second Watchung
Can view road cut best from east end of Parking Area. View to the west is across Newark Basin to New Jersey Highlands
Two possibilities exist for the problems as encountered at this highway cut. One is that a fault zone cut through the basalt in this area; the other is that merely the broken columnar nature of the rock here made steep rock cuts impossible. The embankments at this location were cut originally at the same slopes as the remainder of the highway. Repairs kept the highway closed for over a year while the pavement was otherwise completed. After a long period of cogitation, the slopes were cut back to what you see at present. Rock falls were minimized and the ten miles of highway opened. The additional costs of time and excavating are not known but must have been considerable. Could a good site investigation have prevented this problem? -- a discussion.

Descend from Second Watchung

Probably Brunswick mudstone
Probably Brunswick mudstone with perhaps some more conglomeratic facies toward Highlands to the west

STOP 8. N.J. Highlands to West, Ramapo Fault bends to west.
At Far Hills, we can compare the mapped location of the Ramapo (See Figure 1) with the local topography and discuss the effect of the fault upon local construction, both socially and from a general ground water viewpoint.

Leonard J. Buck Gardens
The proposed (Spring 1980) Somerset County Arboretum is at Moggy Hollow. A bit of New Jersey geologic history will be retained.

STOP 9. Johns Manville Properties site
Development of New Town-Bernards Township/Bedminster
A new development comprised of housing and office buildings is planned for a 1,500 acre site. The site was in litigation for several years and the decisions in the two townships were totally different (and will be discussed). Some 400 acres (higher density - Bedminster) will be sewered while 1,100 acres (low density - Bernards Township) will be on individual or small combined septic systems.
The site has shallow basalts and shales, residual soils, lacustrine deposits, glacial till, high water table, protected streams, steep slopes and is adjacent to the Ramapo Fault. How do you develop this property (the largest single site planned for development in New Jersey)? We'll have a local geology map, test this pit data, percolation test data and some development concepts for discussion -- a seminar.

STOP 10 Route 78 - Berkeley Heights
The highway has been completed to this location for some 5 to 10 years. The road has opened in 1978 from Millburn to Newark Airport (see Figure 1) but there has been extensive discussion concerning the most environmentally sound route (or non-route). We'll discuss it a little more, from primarily a geologic viewpoint.

13: THE PASSAIC RIVER FLOOD PLAIN AND BASIN IN NEW JERSEY
JOSEPH WEISBERG & JOHN MARCHISIN
Department of Geoscience/Geography
Jersey City State College
The field experience follows parts of the Passaic River and its tributaries beginning at the Newark Campus of Rutgers University. The trip parallels the course of the River. It then continues along U.S. Route 46 West to Wayne, Oakland, Lincoln Park and Fairfield in Passaic and Essex Counties near the confluence of the major tributaries; the Pequannock, Ramapo and Pompton Rivers and returns to Newark.
The Passaic River Basin
Created during the Wisconsin age, the present drainage basin of the Passaic River trends in a generally east-to-southeast direction in the Passaic-Essex County Region. The River, rising in Mendham Township, N.J. in Morris County, receives major tributaries as the Saddle River, Mahwah River, Third River, Rockaway River, Whippany River, Pequannock River, Pompton River, Ramapo River, and Wanaque River. All these tributaries drain a natural retention basin formed in the swamp made up of the Black Brook, Troy, Little Piece and Great Piece Meadows. These are part of the remnants of ancient Lake Passaic formed as an impoundment when the Wisconsin glacial advance closed a water gap at Short Hills and subsequently opened another in the Little Falls-Great Notch area.

13: THE PASSAIC RIVER FLOOD PLAIN AND BASIN IN NEW JERSEY

Note debris build-up and desnagging needed.

Dundee Dam
Dundee Dam is the area of demarcation between fresh water above and estuary below Garfield.

STOP 1. Great Notch
The roadway is located in an area that was formerly one of two spillways. The lithology is a basaltic flow of the First Watchung Mountain. This is the second water gap opened at the close of the Wisconsin glaciation.

Junction of Singac Brook and the Pompton River

STOP 2. Weir and flood marker
Weir and flood marker are located at the junction of the Pequannock and Pompton Rivers. Note the bar deposits due to the curtailment of the stream energy by the bridge and pipeline. In this area the watershed traverses a setting of homes and ball fields. Return to bridge, proceed right on Pompton Plains Cross Road.

STOP 3 Intersection of Cross Road and Framingdale Ave
Old Feeder Dam above junction of the Pequannock and Pompton Rivers. Note changeable sign that keeps drowning record. This is a region of severe flooding after heavy rainfall despite the canal that can be followed from this region to Stop Two.

First Watchung flow on right
The ridge on the right is part of the First Watchung flow. Drainage on this side runs toward Pompton Lake, opposite is Wayne Township.

Pompton Lake
Long term siltation and eutrophication has affected the retention ability of the lake. Dredging is to begin in mid-1980. Evidence of an abortive landfill can be seen in part of the lake shore along Rt. 202N.

STOP 4. Upper end of Terhune Park
This location is at the upper end of Terhune Park on Pompton Lake which receives the Ramapo River. It is named for Albert Payson Terhune, a dog breeder and author. It is also the site of boxer Joe Louis's training camp during the 1940's. Residential development lies on both sides of the river; note the undercutting of the retention wall. The area is connected by a small bridge to elevated Rt. 202N where residents park cars prior to flood events. Similar bridges can be found east of this location. A major problem is that the flood plain is swamp woodland resulting in debris jams at many sites.

STOP 5. Newark's Wanaque Reservoir pump station
Newark's Wanaque Reservoir pumping station has a persistent desnagging problem. The Ramapo Fault lies under the talus sloop (north) seen across the lake dam at the pumping station site.

Turn right over the Bridge at Dawes Highway.
The Pompton River forms a meander near its junction with the Pequannock River. Two to four feet of water inundate four blocks of homes during severe flooding.

STOP 6. Sewage Treatment Plant?
2011: There is no description for STOP 6 in the Guidebook. The directions, to go left on Riveredge Drive, take you near here. -- OHM

Sand and gravel pits
Note the sand and gravel pits associated with the Wisconsin glacial moraine. Rt. 23 dips in several locations leading to major flooding following heavy rain, especially near the sites of the Racquetball Spa and MacDonald's Beach and Lake adjacent to the road.

Drainage Ditch
Note the drainage ditch that now enhances flooding near the elevated cottages.

STOP 7. Bridge at Riverside Drive.
The bridge and pipeline are part of the water supply for the city of Newark. The siltation and build up of, debris occur in several locations in a limited area.

STOP 8 Dorsa Ave.
Dorsa Ave. is the designated flood parking area, for area residents. Pia Costa Co. property is a natural retention basin extending into Fairfield, now being developed near Rt. 46E at opposite side of the basin. The railroad trestle shows much evidence of heavy siltation.

STOP 9. Park at Soccer Field.
Note Pompton River undercutting banks and homes with retaining walls opposite the fields. This is Lincoln Park, the site of repeated flood problems during heavy rainfall. The soccer fields have been flooded to a depth of 3-4 feet during flood stage of the river. Make a U-turn in parking lot and return to the Newark-Pompton Turnpike. This road follows part of the flood evacuation route to emergency parking.

Pompton River
Fairfield Rd. follows the course of the Pompton River. Elevated homes are built on the island and opposite bank. Raised bridges create access to the sites of housing.

STOP 10. Two Bridges
This is the junction of the Passaic and Pompton Rivers, a site of frequent flooding after heavy rain. Color differences noting the river junction is often obvious at the bridge junction.

Riverside Drive.
Proceed to Riverside Drive. Homes built on the flood way of the Passaic River between it and a former retention site. Minor flooding occurred with frequency prior to the development of the retention site.

STOP 11. Willowbrook Mall.
A mall developed on the former retention area elevated the region. The homes near Riverside Drive now receive drainage from this parking lot and flood water from the river. Flooding is more frequent and severe. The roadway is township property and not mall property and is designated a flood parking area.

14: LATE TRIASSIC PART OF NEWARK
SUPERGROUP, DELAWARE RIVER SECTION
F.B. VAN HOUTEN
Department of Geological and Geophysical Sciences
Princeton University, Princeton, New Jersey
The Late Triassic part of the Newark Supergroup exposed along the Delaware Valley (Van Houten, 1969) consists of as much as 6 km of nonmarine sedimentary rocks and an associated sill. Its strike generally parallels the northeasterly trend of the basin with a dip of 10-20°NW. Along the northwestern margin the sequence is bounded by Precambrian and Paleozoic rocks of the Reading Prong of the New England Upland. Most of this boundary is a system of high-angle faults (see Ratcliffe, this guidebook), but intermittently Newark border conglomerate overlaps on rocks of the upland terrane. Within the basin and along its southeastern margin Newark strata lie on Paleozoic and Precambrian rocks of the Blue Ridge and Piedmont provinces.
In the northeast (Fig. 3) the Newark Supergroup consists of a lower, locally conglomeratic Stockton Arkose (1840 m, 6000 ft), grading upward into reddish-brown Brunswick Mudstone (more than 1900 m and perhaps as much as 4000 m thick). Along the northwestern faulted border these deposits interfinger with the Hammer Creek Conglomerate. In the central part of the basin the widely-occurring Stockton and Brunswick formations are separated by and interfinger with the dark gray to reddish-brown Lockatong Formation (as much as 1145 m, 3750 ft thick). These major sedimentary rock types comprise rather uniform, widespread units. In the Delaware Valley area a diabase (dolerite) sill is intruded into Lockatong and lower Brunswick strata.
Across the central part of the basin, as seen along the Delaware River, the Newark formations are repeated in three large northwest-tilted blocks. The Flemington and Hopewell faults that bound them may be part of a transcurrent system involving those along the northwestern border as well. Geophysical and subsurface evidence of intrabasin faults near the present margin of the basin (Summer, 1977; Cloos and Pettijohn, 1973) indicates that it was not a simple half-graben.
The Newark Supergroup ranges in age from Karnian (Late Triassic, 215 my) to late Liassic (about 180 my), with Liassic sedimentation beginning about 100 m below the 1st Watchung basaltic lava flow in the middle of the Brunswick Formation (Cornet and Traverse, 1975; Olsen and others, 1980; Olsen, this guidebook). Along the terrane of extension in eastern North America basin development and igneous activity apparently peaked about 190 my ago. In the Delaware River section the Triassic-Liassic boundary presumably is above the preserved Brunswick strata.
FIELD TRIP
Route and Objective
This one-day field trip (Fig. 3) crosses the Newark Basin and Watchung lava flows northwestward from Newark to the border fault, then turns southwestward to the Delaware River section of the Newark Supergroup in the northernmost of three major fault blocks in the central part of the basin. Stops along the 33 km (20 mi.) traverse southward down the section afford study of 1) the Hammer Creek Conglomerate near the northern border fault, composed of Paleozoic carbonate and quartzite clasts in fining-upward sequences marked by calcrete paleosols; 2) the lower part of the Brunswick Mudstone arranged in repeated alternations of reddish~ brown silty mudstone and claystone mudflat deposits; 3) the cyclic lacustrine facies of the analcime-dolomite-rich Lockatong Argillite and its hornfels; 4) the small Byram diabase sill; and 5) the Stockton Arkose with a predominance of Na-feldspar, confirming derivation of most of the Newark basin fill from an eastern or southeastern source. This thick (6 km) sequence is the record of interior basin sedimentation in a major rift valley developed during the early stage of post-Appalachian-Variscan opening of the central Atlantic Basin. The return trip to Newark crosses the Brunswick mudflat lowland in the middle fault block (Fig. 3, 4), then continues northeastward along the south flank of the Watchung lava flows.
The focus of the field trip is on the principal sedimentary facies and the successive changes in sedimentation displayed in the Newark Basin. In this review particular significance is attributed 1) to the eastern upland as the source of the distinctive soda-rich basin fill, 2) to relatively intense weathering in the upland terrane required to produce the large supply of clay in the Lockatong and Brunswick formations, in contrast to the evidence of aridity in the basin reflected in many of the sedimentary features, 3) to a long interval of stability during development of the graben documented by the Lockatong lacustrine deposits, and 4) to several patterns of allocyclic sedimentation recorded in the Lockatong and Brunswick deposits.

14: LATE TRIASSIC PART OF NEWARK
SUPERGROUP, DELAWARE RIVER SECTION

Many zones of reversed magnetic polarity
Interbedded Brunswick (Passaic) reddish-brown arkosic sandstone and mudstone with thin layers of dark gray micaceous mudstone. Local exposures of fining-upward fluvial sequences. See Olsen, this guidebook for revised stratigraphic nomenclature.
Samples across this traverse to the border fault reveal that the 1250m section of Late Triassic Brunswick beds below the 1st Watchung lava flow contains many zones of reversed magnetic polarity. All of the Liassic strata (1750m) above the 1st flow are normally magnetized (McIntosh and Hargraves, 1980, ms; Cornet and Traverse, 1975).

1st Watchung lava flow (Orange Mountain Basalt)
1st Watchung lava flow (Orange Mountain Basalt) 50-65m thick. Basal contact covered. Very thin hornfels facies with small patches of copper minerals. Lower part displays well-developed colonnade with vertical columnar joints. Main body of flow is curvi-columnar zone with closely-spaced radiating joints. (See Manspeizer, this guidebook). Roadcut is 38m deep, said to be the deepest east of the Mississippi River.

Brunswick (Feltville) Fm
Crossing Pleasant Valley Way in mudflat and lacustrine facies of Brunswick (Feltville) Formation between 1st and 2nd Watchung Mts.

2nd Watchung flow (Preakness Mountain Basalt).

Towaco Formation
Crossing lowland in reddish-brown fluvial and dark gray lacustrine Towaco Formation (37m). Rikers Hill (Roseland) National Monument (dinosaur tracks) to SW. Locally some of these lacustrine deposits contain traces of hydrocarbons.

3rd Watchung lava flow (Hook Mountain Basalt)
Crossing 3rd Watchung lava flow (Hook Mountain Basalt). Each Watchung flow was extruded somewhat later than renewed faulting and differential uplift of the flanking highlands that produced fanglomerates (Faust, 1978).

Passaic River
Passaic River, drains Hatfield Swamp on broad expanse of uppermost Brunswick (Boonton) Formation to W.

3rd Watchung flow
North horn of New Vernon anticline in 3rd Watchung flow to S.

Patch of Hammer Creek Conglomerate in low hill to SE.

Ramapo border fault
Narrow gap between Ramapo border fault and west end of New Vernon anticline in 3rd Watchung flow. The fault continues for about 50 miles to the NE end of the basin (see Ratcliffe, this guidebook).

Crossing Passaic River.
In its last stage Glacial Lake Passaic drained northeastward through gaps in the Watchung flows at Little Falls and Paterson. Great Swamp National Wildlife Refuge to S is a swampy remnant in broad syncline above the 3rd Watchung flow.

Narrow gap between 2nd and 3rd Watchung ridges.

Moggy Hollow
Moggy Hollow (Mine Brook Road) between recurved 2nd Watchung Mt. to NW and 3rd Watchung (Long Hill) Mt. to ESE. Early drainage of Glacial Lake Passaic flowed westward through this notch to the North Branch of the Raritan River. West scarp of 2nd Watchung faulted against Brunswick Formation (Adams, 1980).

Watchung Mts. on skyline to E.

Syncline in New Germantown flow in low hills a mile N.

NE end of Flemington Fault
Crossing NE end of Flemington Fault at junction with the border fault (near Lebanon). To S Cushetunk Mt. (diabase) encloses Round Valley Reservoir.

Cambro-Ordovician strata and Precambrian gneiss
Complexly faulted Cambro-Ordovician strata and Precambrian gneiss that project S into the Newark Basin are limited on E by the Flemington Fault.

Remnant of a Taconic klippe
Reddish-brown and gray Early and Middle Ordovician shale with thin beds of chert and limestone. Apparently a remnant of a Taconic klippe (Perrisoratis, 1974).

Ordovician shale overlapped by Hammer Creek Conglomerate.

On northern edge of Hammer Creek Conglomerate
On northern edge of Hammer Creek Conglomerate covering Cambro-Ordovician strata faulted against Precambrian gneiss.

Cross Rt. 579 on border fault.
Large fan of quartzite-rich conglomerate interfingers with Brunswick, Lockatong, and Stockton formations to E and SE. Evidence that movement on border fault occurred throughout episode of basin-filling.

Brunswick Formation
Brunswick Formation S of narrow belt of limestone-pebble conglomerate.

Brunswick Mudstone between fanglomerates.

Continue W on Church Road along border fault.

Quarry in Hammer Creek Conglomerate
Quarry in Hammer Creek (Silurian quartzite clasts) Conglomerate to S. Clasts shattered by crushing in fault zone. Detailed map of Musconetcong Mt. to N and Newark Supergroup S to Frenchtown by Drake and others, 1961, 1967.
2011: Workings apparent in GE photos before 1997. --OHM

Cambrian limestone and border conglomerate
Traverse crosses narrow belt of Cambrian limestone and border conglomerate, and the Brunswick Mudstone between lobes of Hammer Creek Conglomerate. Good exposures of border fault relations across the Delaware River at Monroe (0.5 mi S of Durham Furnace on PA 611).

Cliff on far side of river
Cliff on far side of river above power station shows patterned sequence of middle Brunswick deposits seen at Stop 2. Plateau capped by Coffman Hill diabase sheet (165 m) above gray Brunswick hornfels. The sill is estimated to be about 1400m below the 1st Watchung lava flow.

STOP 1. Hammer Creek Conglomerate
STOP 1 Hammer Creek Conglomerate, Pebble Bluffs at culvert.

Stop 1B. Conglomerate in steep roadcut
Southward projecting lobe of quartzite-rich fanglomerate dipping 10-15 NW. Most clasts are less than 8 cm in diameter, a few are 13 cm long, the largest are 25 cm long. Some clasts are imbricated. Bedding is very poorly developed; cross-bedding is virtually absent.
The poorly sorted detritus is arranged in crudely fining-upward sequences about 7-9 m thick (Fig. 5) with a scoured base, multi-storied units of conglomerate, and calcareous patches and nodules (calcrete paleosol) in the upper sandier part.
Significant items:
1. Outcrop less than 5 mi from border fault.
2. Source probably less than 25-30 mi to N.
3. Clasts and matrix derived from Paleozoic rocks now stripped from the uplands.
4. Fining-upward sequence and calcrete common in alluvial fans.
5. Lensing and channeling well-displayed at south end of bluffs.
6. Rapid gradation southward into distal, finer-grained facies.
7. Fault in ravine between two major outcrops.

STOP 2. Middle Brunswick Mudstone
Long roadcut in essentially horizontal middle Brunswick Mudstone south of Spring Valley Road. Bright reddish-brown mudstone in patterned sequences about 950 m above base of formation (Picard and High. 1963).
Items along 0.2 mi traverse:
1. Normal fault at E end of exposure down to E. Conspicuous jointing.
2. Succession of about 30 massive mudstone and hackly claystone alternations averaging 1.5-3 m thick (Picard and High, 1963). Few units with persistent 1-2 cm beds of siltstone.
3. Abundant burrowing has destroyed lamination in mudstone. Absence of bedding in claystone may be result of small-scale physical disruption.
4. Distinct 2-6 cm layers filling abandoned channel (Fig. 6). Fine-to-medium grained feldspathic sandstone in lower part of each layer derived from southeastern Na-feldspar-rich source area. Some layers are graded. Tops are marked by burrows and shrinkage cracks. Abandoned channel may have been part of inter fluvial drainage of extensive alluvial plain (Allen and Williams, 1979) or a shallow waterway in a clay-flat playa.
5. Hammer Creek tongue of dark reddish-brown Paleozoic quartzite-clast lithic-rich sandstone 3 m above 11.1 road E and W of ravine and culvert.

Perkasie and Land M members of Brunswick
Fm
Dark gray Perkasie and Land M members of Brunswick
Formation 930 m above Lockatong Formation. These are highest of 8 recurring gray units in the Delaware Valley region, centered at 120-137 m intervals (Fig. 1). Several have been traced to NE into Hammer Creek Conglomerate (Fig. 4), as well as 25 km to SW where they interfinger with reddish-brown mudstone. Gray units consist of black, pyritic platy muddy limestone and calcareous mudstone. The Perkasie Member apparently is about 1400 m below the 1st Watchung flow. Intervals of reversed magnetic polarization have been identified below both the Perkasie and L and M units, as well as just below and above the Graters Member lower in the formation (W.C. McIntosh and R.B. Hargraves, 1980, Ms).

STOP 3. Middle Brunswick Mudstone
Middle Brunswick Mudstone, roadside excavation. Well-displayed bedding surface markings, including several sizes of shrinkage crack-patterns, burrows, and small tracks and trails, many probably made by small crustaceans (Boyer, 1979).

Gray units E through H
Gray units E and F exposed in ravine and along side road. Gray units G and H above 100 m higher in section constitute the Graters Member (40 m thick).

Gray unit D exposed in ravine of Warford Creek.

STOP 4. Lowermost Brunswick Fm, Tumble Falls.
Ravine and high roadcut in lowest reddish-brown unit and lowest gray unit C (40 m thick) about 75 m above base of formation (Fig. 1, 7). Reddish-brown mudstone units exhibit three distinctive disruption features:
1. Thin greenish-gray beds with scattered shrinkage wafers.
2. Layers of light brown-weathering dolomitic mudstone 1-3 cm thick, in both pull-apart structures and widely dispersed fragments.
3. Upward-concave surfaces of shearing in tent-like structures 15 to 30 cm high suggestive of gilgai formed in soils by repeated wetting and drying.
The uppermost platy part of gray unit C consists of:
1. Black pyritic mudstone layers 2-3 cm thick with wide, completely crumpled composite and injected shrinkage crack casts of brown-weathering muddy dolomite and minor calcite.
2. Lenses of pyritic peloidal dolomite 10-20 cm thick, with silty round and flattened burrow casts and thin arcuate calcitic skeletal debris (ostracodes?) in the upper part. Many of the peloids are crudely concretionary dolomite with internal shrinkage cracks filled with sparry calcite. They may be algal oncolites.
The overlying massive reddish-brown mudstone contains tiny flecks of pyrite and irregular tan calcareous nodules 1-5 cm long that may be algal structures. Many of them have irregular patches of sparry calcite or are crudely concretionary.

Double Red unit exposed in creek to E
Double Red unit exposed in creek to E is uppermost reddish-brown sequence of analcime-rich chemical cycles assigned to the Lockatong Formation. Thin reddish-brown intervals of this sort are the most analcime-rich and recur in a 105-120 m pattern of long cycles in phase with thick reddish-brown units in the Brunswick Formation

Triple Red unit in abandoned building-stone quarry
Triple Red unit in abandoned building-stone quarry to E about 1000 m above base of Lockatong Formation. Red units were favored for building blocks because of their more interesting variegated colors.

STOP 5A. First Big Red unit, Lockatong Fm
First Big Red unit about 35 m thick, Lockatong Formation, roadside outcrop, north end of Byram road cut. Short chemical cycles consist Of lower platy dark lavender analcime-rich argillite with intraformational breccia and conspicuous shrinkage cracks with large white patches of analcime and dolomite. Upper massive part is reddish-brown, and spotted with tiny specks of analcime and dolomite locally arranged in rosettes of radiating skeletal crystal casts.
Profile of ledges in long Byram roadcut to S (395-730 m above base of Lockatong Formation) outlines succession of short cycles (Fig, 2B).

STOP 5B. Short detrital cycles of Lockatong Fm.
Short detrital cycles in gray sequence of Lockatong Formation. Easily eroded black shale in lowest part and feldspathic (Na-feldspar predominates) siltstone and fine-grained sandstone in the upper part (Fig. 2A). Essentially a very fine-grained distal facies of Stockton Arkose.

First thin Red unit in Lockatong Formation.
Lowest of the several red units in the Newark section (Fig. 1).

STOP 6A. Short chemical cycles of Lockatong Fm
Short chemical cycles in gray unit of Lockatong Formation between 450-550 ft marks (Fig. 8). Gray analcime-rich chemical cycles 2-4 m thick (Fig. 2) are characterized by:
1. Platy lower part of alternating black mudstone and tan-weathering dolomitic layers disrupted by shrinkage cracks and pull-aparts.
2. More massive middle part with extensively disrupted dolomitic layers.
3. Upper more homogeneous analcime-rich part, commonly speckled with tiny patches of analcime and dolomite distributed in a pattern of minute shrinkage cracks. Locally analcime and dolomite occur in sprays of skeletal crystal casts.

Lockatong cancrinite-rich hornfels
Large abandoned quarry in Lockatong cancrinite-rich hornfels (chemical cycles; Fig. 8). Cancrinite is present 130 m (425 ft) stratigraphically above the faulted contact with the Byram diabase to the S. Two well-defined detrital cycles at top of quarry wall.

STOP 6B. Lockatong hornfels and Byram diabase sill
Lockatong hornfels and Byram diabase sill, to south end of roadcut (Fig. 8).
1. White sprays of cancrinite, albite, and calcite at 21 ft mark developed from analcime-dolomite crystals in a chemical cycle, as seen in First Big Red units (Stop 5a).
2. Nepheline developed in hornfels 25 m (11 ft mark) above Byram Sill. .
3. Metal disk 2 m above road at 10ft mark records flood level in Sept. 1955.
4. Faulted upper contact with diabase sill (Fig. 8) and essentially undisturbed contact with xenolith. Lockatong chemical cycles metamorphosed to nepheline cancrinite, calcite, pyroxene and amphibole, biotite-albite hornfels (an aphanitic syenite!).
5. Extensively fractured coarse-grained diabase with abundant joint minerals including calcite, epidote, prehnite, tourmaline, and amphibole. Conspicuous horizontal lineations marked by concentrations of joint minerals are not related to compositional layering in the sill.
6. Vague cyclic pattern of ledges of albite-biotite hornfels S of sill. Nepheline occurs about 30 m (100 ft) below the sill.

Southernmost roadside outcrop of Lockatong hornfels
Southernmost roadside outcrop of Lockatong hornfels, about 80 m below Byram sill.

Crossing estimated Lockatong-Stockton contact.

Uppermost Stockton Formation
Well-bedded reddish-brown sandy mudstone and sandstone in uppermost Stockton Formation.

Raven Rock.
Upper arkosic member 100 m thick (Fig. 1).

Lockatong Creek.
Quarry in Cutalossa Member of Stockton Formation (Fig. 1) high on west bank of river.

STOP 7. Middle Stockton Arkose
Quarry 1 mile N of Stockton. Upper Prallsville Member (Fig. 1) 61 m thick, 760 m above base.
1. Yellowish-gray, well-sorted, medium-grained arkose with only minor reddish-brown micaceous mudstone.
2. Horizontal bedding predominates; with local micro-placers of specular hematite (after magnetite) on bedding planes.
3. Large-and small-scale cross-bedding rare.
4. Intraformational mud-chip conglomerate common.
5. Isolated burrows in arkose and on bedding planes. Micaceous mudstone extensively burrowed.
6. Small yellowish-brown patches common in arkose are limonite after altered iron-rich carbonate cement.
7. Na.feldspar almost twice as abundant as K-feldspar.
8. Very coarse-grained, kaolinized arkose along upper rim of Quarry with clasts of quartz, feldspar, quartzite, and gneiss.

Conglomeratic Solebury Member
Conglomeratic Solebury Member (115 m thick) of Stockton Formation in schoolyard to E.

Arkosic conglomerate of Solebury Member
Roadcut in arkosic conglomerate of Solebury Member. Clasts as large as 8 cm mostly quartzite, rare feldspar and gneiss.

Crossing Flemington Fault at Brookville
Crossing Flemington Fault at Brookville (Fig. 4). To W in Pennsylvania uplifted Cambro-Ordovician limestone is overlain by conglomeratic limestone-clast facies of Stockton Formation.

Lockatong nepheline-cancrinite hornfels
Lockatong nepheline-cancrinite hornfels above Mt. Gilboa diabase. Nepheline and analcime syenites at top of sill probably formed by reaction of a xenolith of Lockatong chemical cycles with a granophyric differentiate of the coarse-grained diabase (Barker and Long, 1969).

Mt. Gilboa trap-rock quarry
Mt. Gilboa trap-rock quarry in unusually coarse-grained diabase (gabbro). Lockatong hornfels along south edge of quarry.

Dilts Corner Fault
Crossing southern branch of Flemington Fault (Dilts Corner Fault).

Brunswick Formation
Join US 202 to NE across Brunswick Formation north of Lambertville sill.

15A: BRITTLE FAULTS (RAMAPO FAULT) AND
PHYLLONITIC DUCTILE SHEAR ZONES (Saturday)
NICHOLAS M. RATCLIFFE
U.S. Geological Survey
Reston, Virginia 22190
Introduction and rationale for investigations
Field investigations at the northern end of the Newark basin begun more than 10 years ago led to the publication of several articles (Ratcliffe, 1971; Ratcliffe and others, 1972) in which a case was made for long continued fault activity in the vicinity of the border (Ramapo fault) in New York and New Jersey.
These articles also called attention to the observation that a series of low-level earthquakes appears to be spatially associated with these ancient faults (Fig. 1).
Since that time, seismic-detention capabilities of the Lamont-Doherty network have been greatly improved and further supplemented by a dense array of stations located on the northern extension of the Ramapo fault in the vicinity of Consolidated Edison's nuclear generating plants at Indian Point (Fig. 2).
Aggarwal and Sykes (1978) document a pattern of seismicity (Figs. 1 and 2) that illustrates that numerous low-level events (Nuttli magnitude 1.5 to approximately 3) are occurring throughout a 30 km-wide zone roughly centered on the trace of the Ramapo fault at depths of 0 to about 10 km. Fault-plane solutions (Fig. 2) obtained by them and by Yang and Aggarwal suggest that motion is currently taking place on northeast-striking
southeast-dipping surfaces. First-motion studies indicate southeast-to-northwest compression and therefore a reverse-faulting mechanism. They conclude that current seismicity in the Ramapo zone is being controlled by reactivation of the northeast-striking steeply southeast-dipping faults which make up the predominant structural grain in this area. They further suggest that the Mesozoic border fault, the Ramapo fault, and its northern splays (Fig.1) are the actual surfaces being reactivated.
The geologic framework of the Ramapo seismic zone, however, is extremely complex. A multitude of faults of different ages have different physical characteristics and contrasting histories. The northeast-trending structural grain of this zone is accompanied by faults of Proterozoic, Paleozoic, Mesozoic and possibly Tertiary and recent age.
Despite the abundant evidence for reactivation of older faults in the Mesozoic, (Ratcliffe, 1971) the Mesozoic and younger faults are not uniformly distributed and do not everywhere coincide with the traces of older faults. Unfortunately, it is not presently possible to produce a tectonic map of this area that accurately shows the distribution of Mesozoic as opposed to older faults. In general, previous studies have not attempted to differentiate Mesozoic faults except where Mesozoic rocks are actually offset. The geologic-tectonic template, therefore, is quite incomplete at present, and any plan to test the hypothesis that geologic structures of Mesozoic age are responsible for current seismicity is severely limited by the lack of appropriate geologic data. Figure 1 shows a new preliminary compilation of fault features

15: BRITTLE FAULTS (RAMAPO FAULT) AND
PHYLLONITIC DUCTILE SHEAR ZONES

Excellent crops of "First Watchung" basalt
Excellent crops of "First Watchung" basalt (Orange Mountain basalt in Olsen this guidebook) Minor faults strike N. 20° E. and dip 80° SE. and have broad shear zones with gouge and subhorizontal slickensides.

Crops of platy jointed basalts of Second Mountain
Crops of platy jointed basalts of Second Mountain (Preakness Mountain basalt of Olsen, this guidebook)

View in distance of Hudson Highlands and Ramapo fault escarpment.

Conglomerate at Montville of Carlston
Excellent crops of the conglomerate at Montville of Carlston (1946) here contain cobbles of hornblende granite, gneiss, epidote veined cataclastic gneiss, "Franklin Marble", and abundant clasts of basalt. These deposits are the youngest rocks in the Newark basin.

Turn left on Old Lane and crops of gneiss boulder conglomerate.

STOP 1. Mulbrook Lane.
Stop at end of circle -Sliver of Cambrian quarzite phyllonite and Ramapo fault breccia
At east side of circle is brown, very shattered, dioritic gneiss(?). To west up slopes by house are crops of vitreous quartzite of probable Cambrian age. Farther west, across small swale, are excellent crops of pale-green, phyllonite gneiss typical of the more ductile deformation zones in the Hudson Highlands.
Sericite, epidote, and needles of actinolite are found in the phyllonite which exhibits strong right-lateral strain slip folds. Ductile deformation is characteristic of these zones along the western edge of the Mesozoic basin.
This quartzite forms one of a series of similar slivers of Cambrian and Ordovician cover rocks that are found west of the Ramapo fault from Boonton north to Tomkins Cove and are interpreted as fault slivers within the ductile shear zones of pre-Mesozoic age. The phyllonite zone forms a continuous belt along the Ramapo to Riverdale where the shear zone may bifurcate with part of the zone extending northward into the Proterozoic rocks along the Lake Inez shear zone.
The cataclastic rocks east of the circle are more typical of cataclastic rocks associated with Mesozoic faulting on the Ramapo.

Low crops of what may be the 4th Watchung lava flow
Turn right on Indian Lane -low crops of what may be the 4th Watchung lava flow; excellent crops in gas pipeline.

STOP 1b. Optional stop. Roadcuts at entrance to golf course at Jacksonville.
Grey to greenish-grey coarse conglomerate (Jc) that contains fragments of "Franklin Marble," detrital graphite, coarse cobbles fragments of hornblende granite gneiss and epidote-veined phyllonite from the older phyllonite west of the Ramapo fault. To the south, a lava flow younger than the "Third Watchung" lava flow overlies fanglomerate. A waterwell drilled in 1979 penetrated 50 feet of basalt and bottomed at 130 feet in grey and red shale conglomerate near this site.
These sedimentary rocks and the lava flows are the youngest rocks known in the Newark basin, based on the palynology of Cornet (1977) who identified these rocks as Sinemurian (middle Early Jurassic).
The nonfolded outcrop pattern of these Sinemurian deposits as compared with the marked northwest-trending folds affecting the Watchung lava flows is notable. This suggests to me that the northwest crossfolds may have formed prior to cessation of fanglomerate deposition.

Stop 2. Large sandpit southwest of traffic circle
2011: Traffic Circle is gone, sand pit is gone, now we have Interstate 287, which in 1980 terminated somewhat south of here. As much of the discussion is about drill cores, it is all copied here. OHM
Just after traffic circle pull over to right. Stop 2 -cross over highway with caution to large sandpit. Bus will turn around and meet us on east bound side of Route 23.
Stop 2. Large sandpit southwest of traffic circle at Riverdale. (See Fig. 5,6,7).
Discussion of core drilling at Riverdale site and bedrock exposures of phyllonitic shear zones and epidote veined cross faults.
Excellent pavement exposures of phyllonitic hornblende granite gneiss and quartzite paragneiss can be seen. Isoclinal folds with axial planes of N. 35° E., 72° E. are crossed by cross faults locally marked by epidote veins cross-faults N. 65° E., 72° SE., N. 30° W., 90°, N. 25° W., 85° NE. show predominant left-lateral and reverse movement.
At the south end of pit, a mylonitic grey, quartzose gneiss is crossed by small crenulations and down-to-east faults. Along the entire border fault, phyllonite where present near the Ramapo is crenulated and micro-faulted with veins of calcite and laumontite. This is typical of Mesozoic mineralization. The phyllonite predates the epidote-rich crossfaults that are of unknown age.
In the sand pits to the south, two continuous core drill holes penetrated the Ramapo fault, see figures 6 and 7. The fault offsets fanglomerate of probable Sinemurian Age of the hanging wall against phyllonitic gneiss of the ductile shear zone.
The actual fault is expressed by 1 cm of soft gouge, consisting of pulverized rock material. Below the fault, green phyllonite, like that seen in the exposures here, is crenulated and displaced on normal faults. Excellent recovery of the fault zone material has permitted thin section examination of the actual fault. The sawtooth contact is preserved showing down-to-the-southeast sense of movement with no evidence for reactivation since this last normal movement. Chlorite-coated surfaces, microbreccia and cataclasite, and "mylonitic" cataclasite with a pronounced fluxion structure are common in the cores. The actual fault is remarkably sharp and well defined in each core. The fault dips 50° SE. assuming a N. 40° E. strike as indicated from outcrop data to the south.
Sections of the actual core will be available for inspection. PLEASE DO NOT REMOVE CORE FROM BOXES.

STOP 3. Lake Inez shear zone exposures in abandoned sandpit.
2011: Sand pit is evident on GE images from 1995. OHM
Pavement exposures of phyllonitic. amphibolite gneiss and pink pegmatite show right-lateral displacement of pegmatite on N. 15° E., 30° SE. dipping shear zones. Chlorite, epidote and sericite mark phyllonite zones. Later cross faults N.65° W., 60° SW. show left-lateral displacement of shear zones and are marked by veinlets of epidote. This is the northerly extension of the same shear zone seen at Stop 2.
Up the hillside to the east, exposure of gneiss show reactivation of gneissic layering. Within this area, all suitably oriented surfaces, gneissic layering, mylonite zones and more brittle thrust faults all show evidence of reactivation in the Mesozoic movement sense. Widespread reactivation in this area follows the steep northeast-trending structural grain developed in "Grenville" and Taconic tectonism.

Abundant brittle faults as well as more ductile ones
Turn right on Skyline Drive -excellent crops in Erskine area show abundant brittle faults as well as more ductile ones. Reactivation has been widespread.

Epidote-filled cross fractures
Near crest of hill at gas pipeline epidote-filled cross fractures with excellent wear grooves suggest Mesozoic reactivation.

Exposures of faulted basalt

Stop 4. (Optional stop) "Coal Mine"
Reports from a desultory mining operation in the late 1800's refer to small coal prospect on the west bank of the Ramapo River 1/4 mile north of Crystal Lake.
This exposure is a sliver of coal black graphitic phyllite ("Annsville Phyllite") similar to the exposure along the border fault at Riverdale. Sketch map figure 9 shows the relations. The sliver of black phyllite is found between two outcrops of gneiss. Very mylonitic gneiss is located to the west. Gneiss exposed east of the sliver has a composite fabric with brittle fractures and abundant microbreccia. The relationships seen here are similar to those seen at Stop 1 and those to be seen at Stop 9 on the Thiells fault. The brittle fractures are spatially related to Mesozoic faulting: the more ductile shears are associated with thrust and strike~slip faulting of probable Ordovician age and represent the southwestward extension of the Canopus zone fault exposed north of the Newark basin. Drill holes for water wells about 400 feet north of this site penetrated granite gneiss in holes 500 feet east of this locality. The "Annsville Phyllite" inclusion does not occur within the Mesozoic border fault but lies west of it as part of the footwall block.

Stop 5. Optional Stop. Cataclasite and fault fabric
Cataclasite and fault fabric in cataclastic gneiss at Ramapo fauit, Suffern.
These small exposures of black, chlorite-coated, cataclastic, hornblende-granite gneiss are much more instructive than the exposures north of Suffern commonly visited by field trips. Excellent chlorite-slick surfaces dip in conjugate fashion northwest and southeast and exhibit down-to-the-south right-oblique slip on southeast-dipping surfaces and down-to-the-west and left-oblique movement on southwest-dipping surfaces. The near-vertical attitude of the extension fractures here and in the Sky Meadow drill core suggests that the rocks of the footwall block have not undergone rotation after formation of the cataclastic fabric.

STOP 6. Union Hill trap quarry
Union Hill trap quarry and contact of lava flows with fanglomerate.
We are permitted entrance with the clear understanding that we will not attempt to enter the quarry proper. Please respect the owners' wishes. Use extreme caution near steep cliffs on west side of exposure.
Superb exposures at the south end of the quarry near the rock crushers show a vertical wall of coarse fanglomerate, enclosing a large boulder of brecciated dolostone in an apparent channel that, in turn, is overlain by an upward-fining cycle ending in fine red shale with greenish slate chips. Vesicular pillow lava directly overlies this shale.
Clasts in the fanglomerate include epidote-rich hornblende granite gneiss, Silurian Green Pond conglomerate, dolostone clasts, and several cobbles of basalt pillows. I interpret the large boulder as a block of breccia from the border fault, and the clasts of pillow basalt as blocks eroded from the southward-advancing Ladentown lava flows.
In the Ladentown-Suffern area, alluvial deposits such as those seen here contain boulders of felsic dikes uniquely traceable to the Rosetown dike swarm. These data indicate, as do the observations at the next stop, that a southerly-directed Jurassic drainage system was present near the border fault prior to eruption of the flows at Ladentown and Mount Union. Perhaps the debris flow material seen here are earthquake-activated deposits formed immediately prior to extrusion of the Ladentown basalt. The basalts seen here are correlated with basalts of the "First Watchung" on the opposite limb of the Suffern cross anticline.
2011 Older GE imagery shows the quarry in its prime, particularly before 2004. OHM

Sky Meadow Road -drill site is at base of mountain to left.

Stop 7. Basalt at Ladentown
Basalt at Ladentown and discussion of drill data from the Ramapo fault.
Note exposures and attitude of red quartz-pebble arkose by road and walk north to ridge behind house. Multiple basaltic lava flows with pahoehoe tongues and snouts as well as small pressure ridges may be seen. BE VERY CAREFUL NOT TO DISLODGE BLOCKS THAT WOULD TUMBLE INTO THE BACKYARDS OF THE HOUSES BELOW. Flow direction obtained from similar exposures suggest that the lava flows were flowing southwest toward the border fault and that the base of the lavas flows are at lower elevations to the southwest.
Drill-core data from Sky Meadow Road suggest that vesicular lava and multiple flows of lava more than 450 ft. thick accumulated near the border fault. These speculations would require a local relief in the basin adjacent to the border fault of approximately 450 ft.
Results of the drilling of the border fault will be discussed (see text).
2011: Very good GE image: 4/29/2004 OHM

Fanglomerate found immediately below Ladentown lava flows just past intersection.

Stop 8. Excellent exposures of Mesozoic fault features
(Optional stop). Excellent exposures of Mesozoic fault features on Cheesecoate Mountain north of Newark basin and view of Newark basin.
This block of Proterozoic gneiss lies east of the Ramapo fault but west of the Thiells fault. It may represent a horst of basement rock that was structurally high during Triassic sedimentation. The principal argument in favor of this contention is the dominance of northeast-striking faults that appear to pass into the basin but do not disrupt the continuous belt of intrusive and extrusive lava.

Traversing possible horst block
We are traversing a belt of gneiss that possibly forms a horst block between the Ramapo fault and the Thiells fault.

STOP 9. Thiells fault.
This small but significant exposure (Fig. 12) illustrates well the difference between Mesozoic faults as seen in drill record and the older mylonitic faults of probable Ordovician age. The Thiells fault is an oblique-thrust fault that juxtaposes the Manhattan Prong rocks against those of the Reading Prong. Abundant ultramylonite, pseudotachylite, and mylonite with metamorphic mineralization affects Proterozoic Y and Paleozoic rocks everywhere along the fault. Figure 12 shows the structural relaltionship exposed in the small quarry behind the houses.
K-Ar data on sericite that replaces mylonitic quartzite yields an age of 379± 13 m.y. (386 m.y. using newer constants). K-Ar data on pseudotachylite from a locality to the north gave an age of 259 ±9 m.y. (264 m.y.). The mylonitization and sericitization associated with the fault are totally unlike that found on any proven Mesozoic fault.
Fracturing in the quartzite at the east side of the exposure may be related to Mesozoic faulting. The similarity of this exposure to that seen at Stop 1 is striking.

STOP 10. Triassic quartzite-rich fanglomerate and cataclastic
Annsville at Cedar Pond Brook, Stony Point. (See fig. 14 for location).
Exposures of black cataclastic "Annsville Phyllite" may be seen at the banks of the small pond west of the dam. Thin-section examination of the east-dipping fabric reveals up-from-the-southeast microdisplacements and abundant clinozoisite and sericite replacement veinlets. This fabric is associated with the Thiells fault that crops out to the west.
A light-colored conglomerate of uncertain origin overlies phyllite and contains fragments of brecciated "Wappinger Limestone" and "Annsville Phyllite". This conglomerate may be a basal triassic conglomerate deposited unconformably on the cataclastic "Annsville Phyllite'. Light-grey carbonate-rich conglomerates similar to this are found along the unconformity at Tomkins Cove to the north.
Large crops of coarse fanglomerate are seen at the dam to the northeast. Quartzite clasts dominate. Cambrian Poughquag Quartzite crops out 1,000 ft to the west where it forms an unconformable cover on the gneiss of the Hudson Highlands west of the Thiells fault. This suggests very local source area for the fanglomerate and further suggests that little post-depositional separation has occurred in this area.
Drill data from cores and trenches 800 ft to the north are shown in figures 13 and 11. A normal fault dipping 70° SE. was intercepted in two vertical drill holes. Cataclasite and gouge typical of other Mesozoic faults marked the fault zone. Unexpectedly, gneiss forms the footwall in Cem. 1. A possible interpretation of the data is shown in figure 13. It is notable that none of the distinctive ultramylonitic rocks seen at the Thiells fault (Stop 9) were found at the border fault. This illustrates the difference between Mesozoic brittle fault products and ductile fabrics of Ordovician faults.

STOP 11. Fanglomerate at Stony Point
Fanglomerate at Stony Point at northern end of Newark Basin.
Limestone fanglomerate unconformably overlies Inwood Marble and "Annsville Phyllite" along the east-west Triassic outcrop belt at Tomkins Cove. Exposures in the railroad cut along the slopes contain inclusions of dolostone traceable to the immediately adjacent dolostone in the Tomkins Cove quarry. Small chips of distinctive biotite-rich hornfelsed Manhattan Schist typical of the contact facies bordering the Cortlandt Complex have been found in the fanglomerate at this locality. Very local sediment sources are suggested by these data.

15B: BRITTLE FAULTS (RAMAPO FAULT) AND
PHYLLONITIC DUCTILE SHEAR ZONES (Sunday)
NICHOLAS M. RATCLIFFE
U.S. Geological Survey
Reston, Virginia 22190
Introduction and rationale for investigations
Field investigations at the northern end of the Newark basin begun more than 10 years ago led to the publication of several articles (Ratcliffe, 1971; Ratcliffe and others, 1972) in which a case was made for long continued fault activity in the vicinity of the border (Ramapo fault) in New York and New Jersey.
These articles also called attention to the observation that a series of low-level earthquakes appears to be spatially associated with these ancient faults (Fig. 1).
Since that time, seismic-detention capabilities of the Lamont-Doherty network have been greatly improved and further supplemented by a dense array of stations located on the northern extension of the Ramapo fault in the vicinity of Consolidated Edison's nuclear generating plants at Indian Point (Fig. 2).
Aggarwal and Sykes (1978) document a pattern of seismicity (Figs. 1 and 2) that illustrates that numerous low-level events (Nuttli magnitude 1.5 to approximately 3) are occurring throughout a 30 km-wide zone roughly centered on the trace of the Ramapo fault at depths of 0 to about 10 km. Fault-plane solutions (Fig. 2) obtained by them and by Yang and Aggarwal suggest that motion is currently taking place on northeast-striking
southeast-dipping surfaces. First-motion studies indicate southeast-to-northwest compression and therefore a reverse-faulting mechanism. They conclude that current seismicity in the Ramapo zone is being controlled by reactivation of the northeast-striking steeply southeast-dipping faults which make up the predominant structural grain in this area. They further suggest that the Mesozoic border fault, the Ramapo fault, and its northern splays (Fig.1) are the actual surfaces being reactivated.
The geologic framework of the Ramapo seismic zone, however, is extremely complex. A multitude of faults of different ages have different physical characteristics and contrasting histories. The northeast-trending structural grain of this zone is accompanied by faults of Proterozoic, Paleozoic, Mesozoic and possibly Tertiary and recent age.
Despite the abundant evidence for reactivation of older faults in the Mesozoic, (Ratcliffe, 1971) the Mesozoic and younger faults are not uniformly distributed and do not everywhere coincide with the traces of older faults. Unfortunately, it is not presently possible to produce a tectonic map of this area that accurately shows the distribution of Mesozoic as opposed to older faults. In general, previous studies have not attempted to differentiate Mesozoic faults except where Mesozoic rocks are actually offset. The geologic-tectonic template, therefore, is quite incomplete at present, and any plan to test the hypothesis that geologic structures of Mesozoic age are responsible for current seismicity is severely limited by the lack of appropriate geologic data. Figure 1 shows a new preliminary compilation of fault features

Sunday Trip

STOP 12. Tomkins Cove quarry in "Wappinger Limestone"
Tomkins Cove quarry in "Wappinger Limestone" (Inwood Marble) and fault exposures north of the Newark basin.
This large quarry in "Wappinger Limestone" (Fig. 14) forms the axial portion of a westward overturned anticline bordered by "Annsville Phyllite" on the west and Manhattan Schist unit A on the east.
Well-layered beige-to-tan weathering quartzose dolostone with phyllite partings forms the central part of the quarry and is bordered on the west by southeast-dipping overturned but highly folded light gray nonquartzose dolostone and black phyllite.
Plane table mapping of the quarry at 1" = 200 with structural geology students at City College has shown that straight forward correlations of units across the quarry is not possible because of eight major fault zones that disrupt the structural continuity. These faults are expressed by red or green zones of clay gouge and phyllonite. Several of these features can be seen on the south face of the quarry exposed in all three levels.
Structural analyses of the fabric associated with these faults indicate that most are southeast-dipping reverse faults with left-lateral or right-lateral components of movement. Minor folds within shear zones plunge steeply down the dip of fault surfaces, commonly normal to slickensides. Faults are located on the limbs or isoclinal overturned folds exhibiting excellent metamorphic fabric and ductile fold styles.
Despite the young looking nature of these faults they appear to be compressional features formed during Taconic dynamothermal metamorphism. Reactivation may have produced the clay gouge and slickensides locally.
Within the quarry, at the extreme west in corner of level 2 and near the southeastern corner of level 3, N.S. steep north-trending faults offset the older clay gouge zones and produce drag folding of older slickensided surfaces.
The western fault is coated with fibrous palygorskite that forms an excellent slickenside lineation. K-Ar dating of this mineral by H. Kruger yielded an age of 183 ± 31 m. y. These data suggest that the prominent clay gouge seams seen in the quarry are older than 183 ± 31 m.y. The palygorskite-coated fault probably is Mesozoic. The fact that the red clay gouge thrust fault zones are not recognized in the Triassic rocks immediately overlying the dolostone to the south also suggests that the main faults seen here are pre-Mesozoic in age.
From these observations, I conclude that the faults seen here are (1) Ordovician thrust faults possibly reactivated in Triassic time to produce gouge, and (2) steep Mesozoic normal and strike-slip faults.
If it were not for the K-Ar age from the palygorskite one might suggest that the clay-gouge zones represent zones of current thrust reactivation in the present compressive stress field related to present-day seismicity. This stop illustrates well some of the complexities in correlation of seismic events with fault surfaces. Any one or all of the faults seen in this area (Stop 9, 10, 12) and shown on figure 14 might satisfy the available fault plane solutions (see fig. 2) available for this area.

At swale, trace of Mott Farm Road fault
At swale, trace of Mott Farm Road fault and cataclastite typical of Mesozoic faults trending N. 70°-80° E. View of Indian Point reactors to east.

Hornblende granite gneiss and abundant semiductile faults
Long up-grade traverses hornblende granite gneiss and abundant semiductile faults with associated lamprophyre dikes on Dunderberg Mountain.

Trace of Timp Pass fault zone
In swale, trace of Timp Pass fault zone of a composite fault zone with evidence of Proterozoic Y, Paleozoic and possible Mesozoic fault activity. This is a major fault that is traceable northeastward through the Hudson Highlands as a metamorphic semiductile fault zone. Very distinctive blastomylonite and a zone of intense folding accompanied by injection of pegmatite mark this fault in many localities. Excellent exposures here of tectonic breccia with inclusions of calcsilicate rocks in a ductile matrix of marble.

Excellent exposures of rusty paragneiss and calc-silicate rock
Note excellent exposures of rusty paragneiss and calc-silicate rock with typical Mesozoic fault fabrics. Exposures of quartz plagioclase gneiss, amphibolite and white alaskite gneiss. Numerous semiductile faults are present in this area.

STOP 13. Overlook - view of River, Dunderberg Mountain
In the nearly continuous exposures along Route 206 from the Bear Mountain Bridge south to Camp Smith numerous faults have been mapped. These faults are predominantly the semiductile type with excellent phyllonite zones and abundant evidence for right-lateral oblique thrust faulting. Correlation of tectonic features across the Hudson to Dunderberg Mountain is excellent and northeast-trending Mesozoic faults are largely absent. Mesozoic faults are predominantly north- and northwest-trending suggesting that the left-handed bend in the Hudson River here is controlled by brittle fractures of Mesozic age.
These outcrops of biotite granite gneiss are not clearly either "Storm King Granite" or "Canada Hill Granite". However, intrusive relationship in amphibolite can be seen in the roadcuts. A comparison of this rock with the "Reservoir Granite" seen at the next stop is in order.

Excellent exposures
Excellent exposures of amphibolite, alaskite, and hornblende granite gneiss ("Storm King Granite") may be seen at sharp bend in road.

Trace of Wallace Pond fault.
Entrance to Camp Smith and trace of a major semiductile fault -- Wallace Pond fault.

STOP 14. "Reservoir Granite" and mylonite zones
The "Reservoir Granite" (Berkey and Rice, 1919) is a widespread granitic rock type east of the Canopus fault zone. Doug Mose has dated a collection of rocks from this locality and from northeast of here and obtained an Rb/Sr isochron of approximately 1250 m.y. for both collections (Helenek and Mose, 1976). The granite has intrusive contacts with amphibolite with which it is commonly associated and may represent either remobilized felsic volcanic rocks (interlayered with amphibolite) or truly intrusive granite.
Excellent mylonite zones cut this garnet-bearing granite. Biotite-rich blastomylonite zones contain syntectonic garnet and intrafolial folds indicating right lateral movement. "A" lineations are subhorizontal. The granite gneiss has biotite and muscovite growing in ductile shear zones and garnet is retrogressively altered to biotite. This tectonic fabric probably represents Ordovician retrogression. The regional grade in Middle Ordovician rocks at this locality is between biotite and garnet zone.

STOP 15. Optional Annsville fault - tectonic breccia
Low road cuts of phyllite.
Exposures of marble with rounded inclusions of gneiss were cited by Bucher (1957) and by Ratcliffe (1971) as evidence for Middle Ordovician erosion beneath the "Annsville Phyllite". I have changed my opinion of this strange rock and interpret this polymict breccia as a tectonic-mylonitic breccia resulting from large-scale extension and flowage in Proterozoic shear zones. Dismembered calc-silicate rocks form the inclusion within the strongly flow-banded marble. Breccias like this are present throughout the Hudson Highlands and are not restricted to zones of Paleozoic faulting.
A fault between "Annsville Phyllite" and this marble is exposed on the north side of these cuts, where the flow-banded marble is dragged in right-lateral sense into the N. 40° E. -trending Annsville fault. Right-lateral minor folds in fluxion banded rocks and minor thrust faults suggest right-lateral, oblique thrust faulting. Exposed contacts in the sand pits to the north, reveal ribbon-quartz mylonite and diapthoritic phyllonite. Syntectonic muscovite, tremolite, actinolite, epidote, and phlogopite are formed in sheared rocks of appropriate composition.
I interpret the Annsville fault as a post-Middle Ordovician, probably Late Ordovician fault, perhaps equitable with the Thiells fault.
Numerous earthquakes have been recorded in the Annsville area, most recently in January 1980 (Fig. 1). Despite the repeated activity, faults of probably Mesozoic age are largely absent. Faults seen at the surface are all characterized by mylonitic-ductile deformation. The northeast-striking, southeast- dipping phyllonitic shear zones satisfy the available fault-plane solutions.

STOP 16. Canopus pluton and western Canopus fault
Park at aqueduct crossing. Canopus pluton and westem Canopus fault: a probable Proterozoic Y fault zone. (See figs. 16a,b,c and 17)
Road cuts of quartz monzonite and granodiorite of the Canopus pluton. Large rectangular microcline-perthite phenocrysts, showing Rapikivi-like mantles, produce a striking igneous lamination trending north to northwest. Ductile shear zones related to the Canopus fault show right-lateral drag of the older fabric. Locally small pegmatite dikes crosscut augen, gneiss and sheared igneous rocks.
The Canopus pluton has been interpreted as a Proterozoic Y syntectonic pluton on the basis of Rb/Sr and K-Ar dating by Dick Armstrong (Ratcliffe and others, 1972). The pluton is deformed in a right·lateral shear couple.

STOP 17. Mylonite gneiss in western Canopus fault
Strongly mylonitic gneiss at the eastern border of the Canopus pluton are exposed in the road cuts. Biotite-rich blastomylonite and more felsic, mylonitic, quartz-feldspar layers produce a strikingly well-layered rock. Reclined, right-lateral, isoclinal folds plunge steeply southwest in the N. 20° E., 80° SE. dipping shear fabric. A strong lineation is produced by the intersection of compositional banding and mylonitic foliation. The tectonic fabric seen here is restricted to local shear zones of Proterozoic Y age.

STOP 18.Eastern Canopus fault
Eastern Canopus fault and overprint by probable Paleozoic fault fabric of the Dlcktown fault. (See fig. 17)
Walk east to base of small cliffs.
This is a complex fault zone, consisting of pink and black biotite-rich augen, gneiss, biotite-rich blastomylonite and intrusive pegmatite. Excellent right-lateral folds, adjacent to ductile shear zones, plunge S. 45° E.
A dark-gray mafic dike crosscuts sheared gneiss and blastomylonite. Metamorphosed dikes like this one are common throughout the Hudson Highlands and are possibly of Proterozoic Z age. Chemically these dikes are distinct from lamprophyres and from Triassic diabases and are currently being, studied. No definitive age data are currently available. However, K-Ar whole-rock dates range from 900 m.y. to 240 m.y. in six samples. The fact that they are metamorphosed, locally foliated, and confined to rocks of Proterozoic age suggests that they are old dikes. A series of small mafic stocks, dikes and small plutons are recognized in the Highlands in the vicinity of the Canopus pluton. Those igneous rocks are mafic to ultramafic and always are strongly metamorphosed. These mafic rocks and plutons represent a very obscure period of igneous activity in the Hudson Highlands but appear to be post- to very late syntectonic in the Proterozoic Y deformation. Locally they are extremely abundant.
A traverse up the hill from this point is instructive and shows increasing progressive overprinting of the Canopus fault fabric by the Annsville-Dicktown fault. In the Dicktown fault zone biotite and garnet are retrograded to chlorite and chlorite rich phyllonite is common. The contrast in the metamorphic grade of a retrogressive mineral assemblages within mylonite rocks may be useful in distinguishing Proterozoic Y faults from Ordovician ones in this area. To the east the Paleozoic grade increases to sillimanite zone and mineral assemblages within mylonites of both Proterozoic Y and Paleozoic age are not distinguishable. Outcrops at this stop, however, are well within the area of relict Proterozoic Y Ar40/39 biotite ages obtained by Dallmeyer and Sutter (1976). These data suggest that the Proterozoic rocks of this area never were heated above the biotite blocking temperature of approximately 350°C since the late Proterozoic. These data are consistent with the assignment of the biotite- rich blastomylonites seen here and at Stops 15 and 16 to Proterozoic Y fault zones. Chlorite-rich phyllonite associated with the Dicktown fault, however, is probably Ordovician.
Throughout the Canopus zone east to the California Hill fault (Fig. 1), no faults having Mesozoic fault characteristics have been recognized, despite detailed mapping. However, as at Annsville, earthquakes are recorded from this zone. The event near the California Hill fault (Fig. 1) is associated with a zone of very ductile, probably Proterozoic faulting.
Faults commonly dip 80° SE. or NW. but locally may dip 60° SE. These tectonic features (Figs. 1 and 4) probably extend through the continental crust and must be present as significant inhomogeneous (weak) zones at depths of 1-10 km where earthquakes are occurring. I interpret this highly faulted zone as the ancestral grain that localized Mesozoic faulting in the area to the south traversed on the first day of this field trip. (See fig. 16c)

Exposures of "Canada Hill Granite"
Exposures of "Canada Hill Granite" and rusty biotite-sillimanite paragneiss typical of the western block of the Hudson Highlands.

Canopus Lake - crossing Denny town fault
Canopus Lake - crossing Denny town fault that marks the beginning of Canopus fault zone, crops of rusty paragneiss, amphibolite marble, calc-silicate rock, and magnetite-bearing quartzite.

STOP 19. Dennytown fault, Poughquag Quartzite inlier
(See figure 1 for location)
This exposure marks the southwestern limit of a series of faulted slivers of basement gneiss and Poughquag Quartzite that extend southwest from the front of the Hudson Highlands along the Denny town fault. These inliers are surrounded by phyllonite zones marked by chlorite-sericite-epidote mineralization and ductile fold styles. Fold axes, within phyllonite plunge southeast in 80° to 60° SE. dipping surfaces. Excellent right lateral offsets and folds are seen in thin section and outcrop. A northeast plunging "a" lineation defines the probable slip direction.
I interpret this fault as an Ordovician, right-lateral, oblique thrust fault parallel to the Proterozoic Y fabric in the gneiss. The northward extension of these fault zones is uncertain but they probably extend out into the Paleozoic cover rocks north of the Hudson Highlands.
Participants from Saturday's trip may be struck by the similarity of these exposures to the quartzite-phyllonite zone seen on Stop 1 near Boonton, N.J. This similarity should drive home the point that phyllonitic shear zones of probable Paleozoic age are regionally important features within the Ramapo seismic zone. Earthquake activity here seems to be more associated with semiductile features such as the Denny town fault than with brittle-type Mesozoic faults.

16A: RIFT TECTONICS INFERRED FROM VOLCANIC
AND CLASTIC STRUCTURES (Saturday)
WARREN MANSPEIZER
Newark, N.J.
Tholeiitic basaltic lava flows and intrusives of Late Triassic and Early Jurassic age clearly mark and distinguish the upper part of the rift-valley stratigraphic sequence in the onshore and offshore basins of eastern North America and northwest Africa. These igneous rocks were emplaced over a vast area, perhaps 2500 km long and 1000 km wide, during an episode of crustal extension and sea-floor spreading and hence exhibit a variety of structures reflecting the complex history of the basin at that time. Where these volcanics are interbedded with sediments having paleocurrent and/or paleo-environmental attributes, important conclusions may be deduced about the tectonic behavior of the basin from each rock type.
The objective of this field trip is to study a typical rift facies of interbedded volcanics and sediments, thereby providing a frame-work for interpreting the tectonics of the basin during crustal extension and sea-floor spreading. Figure 1, a diagrammatic sketch through the section, shows the kinds of structures and facies that we shall observe on the field trip. Many of these features, such as tumuli, subaqueous flow lobes and palagonite foreset bedding have not been reported from rift volcanics of eastern North America. Figure 2 shows the route of our field trip.

16: RIFT TECTONICS
INFERRED FROM VOLCANIC
AND CLASTIC STRUCTURES

Sandstones and mudstones
Alternating beds of red sandstone and mudstone with a few thin interbeds of gray siltstone and dark gray to black micaceous shale, occurring below the first overpass. These siltstones yield a probable Upper Norian palynoflorule and occur about 1100 m below the First Watchung Mountain Basalt (Cornet and Traverse, 1975, p. 27). Sporadic exposures of sandstones and mudstones with fining-upward sequences, chacteristic of meandering streams, occur along Interstate 280 for the next 4.4 miles.

STOP 1. Passaic Formation: Central Basin Facies
Objective: to examine a fluvial sequence of the central basin facies.
Background: information for this stop is found in the text under, 'Central Basin Facies: Fluvial-Playa.'
Figure 22, a stratigraphic section of this stop, shows characteristics of the fining-upward sequence, namely: cut-and-fill channels, channel lag concentrates, cross-bedded arkosic sandstones, overbank deposits of reddish-brown mudstone with calcrete paleosols, gray-green to green shales with plant fragments, worm burrows, roots (?) and copper mineralization (chrysocolla and malachite.)
Petrographic and paleocurrent studies along this highway, and elsewhere in this stratigraphic horizon, indicate that the sediment was derived from a deeply weathered metamorphic terrane to the north and east., and transported to the basin across a broad southwest-sloping pediment.

Great Notch, on the western horizon
Great Notch, on the western horizon, is a 'wind gap' cut into the First Watchung Mountain by streams draining Glacial Lake Passaic.

Contact Passaic Fm / Orange Mountain Basalt.
Contact of the Passaic Formation with the overlying Orange Mountain Basalt. The columnar basalts of the lower flow unit is well exposed as is the contact with reddish-brown ripple-marked sandstones of the Passaic Formation.

Passaic Formation / Orange Mountain Basalt.
Contact of the Passaic Formation with the overlying Orange Mountain Basalt. The columnar basalts of the lower flow unit is well exposed as is the contact with reddish-brown ripple-marked sandstones of the Passaic Formation.

Beginning of the upper flow unit
Beginning of the upper flow unit with its characteristic ropy pahoehoe-pillowed surface.

Transverse cross section of subaqueous flow lobes.
Transverse cross section of subaqueous flow lobes. Note the arcuate pattern of the pillow lava complex. These structures will be examined in the lower and upper New Street Quarries at Stop 3.

STOP 2. Contact of the Orange Mountain Basalt with underlying Passaic Fm.
Objective: to determine the paleoflow direction of the lava and the paleocurrent direction of the underlying sediments.
Background: see the text under, 'paleoflow structures in rift volcanics: pipe vesicles and pipe amygdaloids.'
Figure 6 is a composite sketch of the structures found at the outcrop. The section shows the lower flow unit of the First Watchung basalt with southwest plunging pipe amygdaloids and vesicles, overlying an irregular surface of cross-bedded (southwest dipping) pebbly arkosic sandstones and conglomerates with large clasts of rounded quartzite, carbonate and shale chips. Figure 7, a stereographic projection of the paleoflow and paleocurrent data, indicates that the lava flowed to the northeast transgressing a regional sedimentary paleoslope inclined to the southwest.
This site is also of some historical importance. Alexander Hamilton, inspired by the power of the Passaic River as it cascaded over the Great Falls of Paterson, informed the New Jersey legislature that he had found the ideal site for industry in the new nation.

STOP 3. New Street Quarry
Orange Mountain Basalt: Upper Flow Unit, New Street Quarry.
Objective: to examine subaqueous volcanic structures including: pillow lavas, flow lobes, fissure eruptions, a volcanic cone (?), and zeolite mineralization. Caution should be exercised in the quarry and participants should not climb the upper quarry walls.
Background: An extensive text is developed for this stop and found under 'pillow lavas and subaqueous flow lobes'.
The walls of this quarry and an adjacent quarry, long favorites of mineral collectors for their beautiful and diversified suite of zeolites, also exhibit a splendid array of subaqueous volcanic structures (see Fig. 11). Participants should first examine the structures of the east (or far) wall, noting the amygdaloidal and vesicular upper contact of the lower flow unit and the overlying Tomkeieff sequence, which is overlain by bedded pillow lavas and a second Tornkeieff sequence. Note also spiracles in the lower colonnade and cross-sections of polygonal joint sets of the entablature. Follow the structures along the south wall, walking west, and note the increase in pillow lavas with a concomitant decrease in massive basalt. On the west wall we may observe the characteristic concave-downward arcuate form of overlapping flow lobes in transverse section. Pinching and swelling pillow buds elongated N-S in arcuate bundles distinguish the flow lobes from the overlying bedded pillows which appear to be stacked one on the other and elongated E- W.
Although the contact between the two types of pillows appears to be unconformable, the absence of eroded pillows along the contact indicates that they are conformable. Note the manner in which the younger pillows cascade off the flow lobe, building up slopes of about 40°. In general, the pillow buds are very dense with radial joint structures and few minute vesicles, indicating that they formed in deep water.
The absence of pillow-derived debris within the interstices of pillow complexes indicates that the debris was washed out of these pockets in a well-agitated lake. The occurrence of interstitial angular basaltic fragments (surrounded with quartz, calcite, perhnite and other zeolites) indicates that the fragments were derived from the checkered exterior rinds of the pillows by circulating fluids, perhaps ground water. The original debris was probably redeposited in a deeper part of the basin, along the border fault.
The flow lobe appears to flare out and to plunge westward, where it may be studied in the walls of the lower New Street Quarry. At some appropriate time, we shall enter that quarry as a group. Figure 12, a field sketch of its east wall shows three distinct episodes of vulcanism: (1) an older episode of flow lobes; (2) a medial phase of massively bedded, moderately coarse-grained igneous rock that slopes away from a central point and overlaps the distal and advancing end of a flow lobe; and (3) a younger zone of bedded pillow buds that overlie both the steep slope of the subaqueous volcano (?) and the flow lobe. The origin of these features should encourage a lively discussion.

STOP 4. Feltville Formation
Feltville Formation in contact with the overlying Preakness Basalt.
Objective: Primarily to have lunch in a pleasant setting, and secondarily to examine a fluvial-deltaic (?) facies.
Background: A stratigraphic section of this site is found in figure 23, and shows two fairly complete fining upward sequences of point bar deposition, overlain by the Second Watchung lavas along an irregular contact with pahoehoe structures, pillows, soft sediment loading structures and injection features into the underlying mud.
Note the typical fining-upward sequence with its channel deposits of coarse clastics, overlying planar beds of sandstone, which is overlain by large, low angle crossbedded sets and then by a thick sequence of ripple drift cross-laminations with shale interbeds that are cut through by a very large channel with cross-bedded pebbly sands, plant debris and thin stringers of coalified plants. The channel sands are overlain by low angle planar cross-beds, trough cross-beds and finally by fine-textured ripple drift cross-lamination. Convolute bedding and parting lineations are common with the prevailing trend of the latter striking N 5O° E. Parting lineations, in conjunction with the cross bedding, indicate that the paleocurrent was to the southwest. We can easily follow these beds to the south (using the basalt as a marker bed) where they interfinger with distributary-type channel sands of the deltaic sequence.
Look for evidence of strike-slip movement on the far wall. The pockets of pillow lavas indicate that the lava flow dammed an existing lake or stream. The pillows are perhaps best exposed in the roadway adjacent to the lunch stop, where they may be examined against the fine-splintery columnar jointing so diagnostic of the Second Watchung lavas.

First Watchung lavas and Glacial Lakes
The road is underlain by basalts of the first Watchung lavas. Glacial lakes are abundant in the area. As we proceed west onto Long Hill Road we will descend the backslope of the First Watchung.

STOP 5. Feltville Formation
Feltville Formation: subaqueous fan, marginal border facies.
Objective: to determine the provenance and depositional setting of these massively bedded conglomerates.
Background: field descriptions of this stop are found in the text under 'Marginal rift facies: fan delta'. Note figures 26 and 27. The section, about 45 m thick of coarse-grained and poorly sorted clasts with average grain size of about -4 to -6 phi (16 mm to 64 mm), occurs immediately below the base of the Second Watchung lava. The clast population has a graphic mean (Folk, 1974) of -4.5 phi and is very poorly sorted with a standard deviation of 2.4 phi (Fig. 28). The clasts are composed principally of carbonate, quartzite, low-rank metamorphics and most notably, vesicular basalt. Many of the clasts are reasonably well-rounded, imbricated, and show subtle grading which is perhaps one of the most distinctive - but elusive - aspects of this facies. In order to determine grading patterns of sedimentation, we measured the grain sizes of all clasts with a phi-ruler on a 2.5 cm sampling grid drawn perpendicular to bedding. The data, included on representative graphs of that exercise (Fig. 29) show: (1) the cyclical pattern of deposition and subtle stratification; (2) each cycle seems to begin with an inverse grading sequence, marked by a subtle increase in grain size upward in section, and followed by an abrupt decrease in grain size; (3) reverse grading is repetitive with each episode transporting slightly coarser components; and (4) many cycles are symmetrical.
Each complete depositional cycle consists of an erosional basal contact followed by a depositional couplet of inverse grading, followed by normal grading and an upper contact marked by finely comminuted particles in ripple drift cross-stratification (Fig. 26). Complete cycles are rare, and much of the section is marked by subtle and shallow cut-and-fill channels, (Fig. 27).
At the western end of the outcrop, the beds are graded and the bedding planes have a slightly arcuate pattern. Are we looking at a transverse section of a fan, or is this a drag structure along a fault?
Note that the section lacks features commonly associated with Triassic-Jurassic fluvial deposits, namely: rootlets, caliche deposits, plant fragments, dessication cracks, red beds, dinosaur footprints, worm burrows and overbank deposits.
Observe clast rounding, imbrication and composition.
Although quartzites, carbonates, and low rank metamorphics are fairly common, perhaps the most significant clasts are the vesicular basalts. Together with the imbrication direction, it suggests that the lavas of the First Watchungs flowed westward over a low-lying fault escarpment.

Most of the lakes in the area resulted from glaciation.

STOP 6. Boonton Formation (Fanglomerate).
Marginal Border Facies
Objective: To examine an alluvial fan facies within the border fault zone.
Background: Field descriptions and photographs of this section are included in the text under, 'Boonton Formation: Marginal Border Facies'.
Because the section has been polished by glacial scour, conglomeratic structures are displayed in great detail. Cyclical and laterally continuous beds of poorly sorted debris flows grading upward into cross-bedded and ripple marked sheet-flood deposits are characteristic of the section (Fig. 34). Many of the cycles are incomplete, having been partially eroded by a subsequent debris flow. Each section is about 2 to 3 cm thick and occurs within larger cyclical units of about 1.5 m thick. The clast population has a graphic (Folk, 1974) mean size of -3.3 phi, and an inclusive graphic standard deviation (Folk, 1974) of 2.2 phi (Fig. 28); it is, therefore, very poorly sorted. In general, the grains are angular and primarily composed of a quartzite, gneiss and vesicular basalt with subordinate amounts of amphibolite, slate and greenstone schists. They appear to have been derived from a local source.
Some of the primary structures seen at the section include: ripple drift cross-lamination, dessication cracks, cut-and-fill channels, normal and inverse grading, sand waves, parting lineations, antidunes (?), random fabric, sand shadows, dreikanters and oriented clasts (Fig. 33).
Particle orientation was determined from clasts having a length to width ratio of at least 1.3: 1. The prevailing long axis orientation is west-to-east with clast imbrication to the west (Figs. 31 and 32). This is compatible with a preliminary paleocurrent study showing that the clasts were transported to the basin by east-flowing streams. The occurrence of aligned ventifacts indicates that the wind was an effective agent of erosion, and may explain the deficiency of fine sand and clay size particles on the alluvial fan.

Boonton Reservoir
Boonton Reservoir on left-site of famous Boonton fish fossils.

Glacial Lake Passaic
We are traveling on the lake bed of glacial Lake Passaic, which formed as the meltwaters became impounded between the N.J. Highlands on the west, the Second Watchungs to the east and south, and the moraine to the south. At its greatest extent, the lake was 30 miles long, 10 miles wide and 240 feet deep (Kummel,1940).

Passaic River

Third Watchung lava flow on S horizon (see Olsen, this book).

Backslope of the Second Watchung lava flow.
Coarse-grained diabasic texture may be examined near upper part of the exposure.

Lava / Feltville Fm contact
Contact of lava flow with the underlying Feltville Formation. Note the fine-textured joints of the entablature. When exposed during road construction, the formation consisted of cross-bedded feldspathic sandstone (10 m) underlain by thin stringers of coal with underclay. A similar section may be studied in the parking lot of the Daughters of Israel Nursing Home, 1155 Pleasant Valley Way, West Orange (about 3/4 mile south).

Backslope of the first Watchung lava flow
Outlines of pahoehoe toes may be studied in roadcut.

STOP 7. Orange Mountain Basalt; lower flow unit
Objective: To examine a Tomkeieff sequence of colonnades and entablatures near the classical site of O'Rourke's Quarry. (See photograph facing the title page of this article.)
Background: This structure is described in the text under 'Columnar Jointing'.
When built in 1969, this road cut was the deepest federally-financed highway cut east of the Mississippi River. About 33 m deep, the cut exposes a complete section of the lower flow unit of the Orange Mountain Basalt, and a broad array of joint patterns that formed as the basalt cooled. The large "basin" structure on the southeast wall was first described about 100 years ago by J.P. Iddings (1886) of the U.S. Geological Survey in John O'Rourke's Quarry, about 300 m south of the roadcut. While such complete structures have not been observed elsewhere in the Watchungs, similar joint structures, e.g. chevrons, oblique and reverse fans and rosettes (terminology of Spry, 1962) may be studied in this roadcut and in almost every quarry along strike for a distance of 80 to 100 km.
This structure (about 33 m thick) conformably overlies a fluvial red bed sequence of shales and sandstones and, when first exposed, displayed a complete Tomkeieff sequence of: (1) a lower colonnade (10-15 m); (2) entablatures (20-30 m); and (3) an upper colonnade (1-2 m) (Fig. 17). While the lower colonnade is composed of massive 4-5 or 6-sided polygonal and subvertical prisms, the entablature is composed of long (25-30 m) slender narrow joint prisms that radiate from an apparent focus. Several juxtaposed bundles or sheafs of radiating prisms may be observed in the roadcut, comprising fan and chevron-like features. Cross joints, intersecting radiating prisms at high angles, are prominent and appear to be concentrically arranged about the apex of radiation. An incomplete section pseudo-columns overlie the entablature.
Figure 18, depicting mineral and textural variations within the structure, shows an increase in grain size, an increase in the abundance and size of the interstitial glass, and an increase in the olivine content in the entablature (Fig. 19). This suggests that although cooling may have proceeded very slowly from the sediment-volcanic interface, once a ground mass capable of transmitting stress was established the remaining melt cooled almost instantly. The obscure joint pattern in the upper colonnade may form from convective heat loss near the upper part of the flow.
The early cooling history of the magma is manifested by well-developed horizontal striations observed on the joint surfaces of the lower colonnade. While Iddings (1886) may have been the first to report horizontal striations on joint surfaces (from O'Rourke's quarry), James (1920) speculated that these striations represent successive stages or pulses in which the rock broke and the columns formed. Recent studies by Ryan and Sammis (1978), and Justus and others (1978) at this site show that the striations are records of discrete thermal events, characterized by sudden periods of crack advance in the cooling basalt. Features such as chisel marks, pinch and swell and kink structures on the curvi-columnar joints may also represent an episodical cooling history. Each of these features may be observed on the walls of the highway cut.
The striations reported by Iddings (1886) show up on joint surfaces of the lower colonnade as cyclical bands of smooth and rough zones, about every 5-7 cm. Ryan and Sammis (1978) report that as the crack growth proceeds, the first-formed zone is smooth and associated with a thermal shock event; the second zone is rough, has positive relief, and is associated with the halting of each crack advance.
Joints of the entablature are also cut by concave-upward "dish-like" joints that are cut by strike-slip faults. While the origin of this structure is debatable, it trends N 50° E and evidently formed after the basalt cooled and before faulting occurred.

Dike intrusion into fluvial channel sands.

16B: RIFT TECTONICS INFERRED FROM VOLCANIC
AND CLASTIC STRUCTURES (Sunday)
WARREN MANSPEIZER
Newark, N.J.
Tholeiitic basaltic lava flows and intrusives of Late Triassic and Early Jurassic age clearly mark and distinguish the upper part of the rift-valley stratigraphic sequence in the onshore and offshore basins of eastern North America and northwest Africa. These igneous rocks were emplaced over a vast area, perhaps 2500 km long and 1000 km wide, during an episode of crustal extension and sea-floor spreading and hence exhibit a variety of structures reflecting the complex history of the basin at that time. Where these volcanics are interbedded with sediments having paleocurrent and/or paleo-environmental attributes, important conclusions may be deduced about the tectonic behavior of the basin from each rock type.
The objective of this field trip is to study a typical rift facies of interbedded volcanics and sediments, thereby providing a frame-work for interpreting the tectonics of the basin during crustal extension and sea-floor spreading. Figure 1, a diagrammatic sketch through the section, shows the kinds of structures and facies that we shall observe on the field trip. Many of these features, such as tumuli, subaqueous flow lobes and palagonite foreset bedding have not been reported from rift volcanics of eastern North America. Figure 2 shows the route of our field trip.
This trip contains only those places not visited on trip 16A.

16B: RIFT TECTONICS INFERRED FROM VOLCANIC
AND CLASTIC STRUCTURES (Sunday)

STOP C. Lower Flow Unit Preakness Basalt.
Objective: To examine tumuli (also known as pressure domes or schollendomes, Macdonald, 1953).
Background: Information about this structure is found under Tumulus, also figures 8 and 9. The exposed tumulus structure, about 7 m high and 15 m wide, consists of a central core of massive basalt with columnar joints (1-1.5 m wide), an overlying zone of radiating entablature joints (0.5-1.0 m wide), and an upper colonnade with poorly defined columnar joints and vesicular to brecciated basaltic glass. The structure is overlain by a pillow-pahoehoe complex that thins along its crest and thickens along its flanks and adjacent troughs. A second flow unit overlies both structures and consists of massive colonnades with bent pipe amygdaloids, indicating that the lava flowed towards the crest of the tumulus. Although this tumulus did not feed the second flow unit, it appears to have fed (through the overlying brecciated zone) the pillow-pahoehoe complex.
The section also shows an interesting assemblage of ellipsoidal bunlike structures, including: pahoehoe toes with concentric layers of vesicular and non-vesicular basaltic glass, and with flat bottoms and rounded tops; (2) flattened lava tubes (?) with concentric structures and hollow interiors in transverse cross section; and (3) pillow buds with circular transverse sections and ellipsoidal longitudinal sections, vesicular cores and pipe amygdaloids elongated radially near the bud edge. and radial and concentric joints in cross section. Moreover, note: the variety of bun shapes and sizes; the volcanic debris separating these bun-like structures; the occurrence of several tumuli crests at different heights along the exposures; and the surface topography of the lava flow as expressed by the tumulus surface.
Did this structure form in water? When did it form relative to the pillow-pahoehoe complex? How do these bun-shaped structures compare to those at the New Street Quarry? Are the buds a tangled mass of independent sack-like structures or a tangled mass of cylindrical interconnected pillow buds, lobes and pahoehoe toes? What does the structure tell us about the relationship between topography, isotherms and the formation of columnar joints. We shall continue our discussion of this point at our next stop.

2nd flow unit of the First Watchungs
Vesicular pahoehoe flows of the 2nd flow unit of the First Watchungs behind stores on right.

A wind gap cut into the First Watchung Basalts.

Eagle Rock Reservation. Park Buses -Lunch Stop.

Trap rock quarry
Trap rock quarry, entablature structures may be seen from the road.

Red beds with fining upward cycles.

Entering the South Mountain Reservation
Back slope of the First Watchung Mountains on the left (east); the Second Watchung Mountain on the right (west).

STOP E. Feltville Fm contact Orange Mountain Basalt.
Feltville Formation in contact with the underlying Orange Mountain Basalt.
Objective: Primarily to determine whether the second flow unit is intrusive or extrusive. And secondarily to examine the carbonate sequence near the base of the Feltville Formation.
Background: This section is discussed in the paper under 'Emplacement of the Watchung Lavas', and 'Central Basin Facies: Lacustrine-Deltaic Facies', see figure 20. The issue before us at this site is the same as the one confronted by a group of eminent geologists more than 100 years ago, including: Cooke (1868), Russel (1878), Davis (1882) and others. Figure 20 will be helpful in your examination. Note the irregularity of the contact, the 'baked' mudstones and sandstones, vesicular sandstones, the occurrence of marble float along the carbonate horizon, the occurrence of pillow lavas, and the stratification in the basalt. Moreover, note pillow vesicularity, pipe vesicles and amygdaloids elongated radially near the bud edge, and brecciated clasts of basalt and red beds within pillow interstices.
Are the pillow buds independent sack-like structures or are they interconnected cylindrical-to-sack-like masses? Do they rest directly upon each other, or are they separated by baked sediment, weathered sediment or basalt, or an old soil horizon? Is the basalt stratification a relict sedimentary structure or a primary volcanic structure? Is the irregular sedimentary-igneous contact an old soil horizon or an intrusive-baked contact? Recall that this horizon is stratigraphically equivalent to the section that we studied at the New Street Quarry.
Upstream the pillow buds become larger, more numerous, bedded, and overlain by a complete Tomkeieff sequence. This part of the section is quite similar to the upper part of the section at New Street.
The second reason for examining this section is to study the sequence of shelf carbonates and siltstones that unconformably overlie the basalt, and crop out sporadically from Feltville to Pluckerman's Ravine.
The carbonates occur as thin discontinuous limestone lenses, about 5-20 meters above the igneous contact, and interbedded with gray and reddish-brown shale and gray calcareous thinly laminated siltstone. A trench dug into the hillside exposes the section (Fig. 24)(McGowan. 1980). The limestones, about 10 cm thick and 100 m long, display a variety of shallow water structures including: cross-bedding, dessication cracks, rounded intraclasts cemented with sparry calcite, ripple marks, abraded algal debris and erosional lower contacts. Although some of these features are ambiguous with respect to environments of deposition, the assemblage of structures point to a shallow water carbonate bank. See also McGowan (1980), who has made an extensive study of this formation. Olsen (pers. comm.) also reports the occurrence of thinly laminated deep-water carbonates with whole fish fossils stratigraphically beneath the shelf carbonates. Plant fragments, dinosaur footprints, fish fossils, algal mats, ostracods, and one branchiopod shell are reported from this section (Olsen, 1975; Dahlgren, 1975; McGowan, 1980). Flaser bedding, ripple drift cross-laminations, parting lineations and small scale trough cross beds may be observed in the overlying siltstones and sandstones. The average direction for the trough cross beds and parting lineations is 180° and 145° respectively (McGowan, 1980).

17: FOSSIL GREAT LAKES OF THE NEWARK SUPERGROUP IN NEW JERSEY
PAUL E. OLSEN
Bingham Laboratories, Department of Biology
Yale University, New Haven, Connecticut
Because Newark Basin lacustrine rocks are (1) often composed of sedimentary cycles, (2) traceable over very large areas, and (3) unusually rich in fossil remains, they are among the most interesting and challenging of Newark Supergroup deposits. While lacustrine sequences are found in all sedimentary divisions of the Newark Basin, those of the Lockatong, Feltville, and Towaco formations are known in greatest detail and are therefore the focus of this field trip. I concentrate on the interpretation of the lake sediments, paying special attention to some fundamental problems in their interpretation. In addition, I touch on some relevant paleozoology.
2011: Views along I 80,which duplicate those from NYSGA 1980 Trip 1, have not been reproduced here.

17: FOSSIL GREAT LAKES OF THE NEWARK SUPERGROUP IN NEW JERSEY

Passaic Formation
Newark Campus sits on late Norian or earliest Rhaetic sandstones and siltstones of the Passaic Formation.

Newark Museum on left

Along the strike of the Passaic Formation.
Route 21 follows the west bank of the Passaic River along the strike of the Passaic Formation.

Pass Belleville Avenue
Just north of Belleville Avenue and 1.1 miles east of Route 21 is the old Schuyler Copper Mine worked from about 1720 to about 1900 (Lewis, 1906). The ore occurs in gray arkosic sandstone and gray siltstone invaded by small dikes and sills of diabase. Lewis (1906) lists chalcocite, chrysocolla, and malachite as the major copper minerals with minor amounts of azurite, cuprite, and native copper.

Fragments of phytosaur skull
Fragments of phytosaur skull and reptile footprints found in Passaic Formation "brownstone" quarry near here (Edwards, 1895; Lull, 19S3).

Route 3 cuts across strike through Passaic Fm.
Route 3 cuts across strike through Norian and Late Carnian Passaic Formation. This portion of the Passaic Formation is the lateral equivalent of the entire Delaware River section of the Passaic and upper Lockatong (see Van Houten, this Fieldbook)

Entering Hackensack Meadows.
About 0.2 mi. southwest of this point are excellent exposures of Passaic Formation including a series of gray sandstone beds (ca. 2 m) stained with chalcocite, malachite and azurite. Old (?exploratory) shafts are evident in the outcrops. Lithology of copperbearing units very similar to beds at Schuyler Mines. I have found reptile footprints assignable to Rhynchosauroides brunswickii and Grallator sp. and in addition, horseshoe crab tracks called Kouphichnium and Scoyenia burrows in the fine red siltstones surrounding the gray sandstone. Lower red beds of exposure contain well developed caliche horizons similar to those described by Hubert (1977) from more or less contemporary beds of the New Haven Arkose (Hartford Basin). Further southwest, (0.3) mi are additional exposures along former Erie Lackawanna Railroad tracks showing an unusual reverse fault dipping to the west and downthrown on the east. Slickensides confirm the dipslip nature of the fault. Hackensack Meadows, over which Route 3 crosses, are underlain by relatively finegrained red and minor gray beds of Passaic Formation.

Lateral equivalent of Graters Member?
Ridge just south of here (Secaucus) has exposures of gray sandstones and siltstones which could be lateral equivalent of McLaughlin's (1948) Graters Member.

Open cut in Stockton Formation
On right is open cut in Stockton Formation and west portal of tunnel for Penn Central Railroad. Cut exposes upper Stockton beds described by Darton (1883). At east end of cut at tunnel is excellent exposure of the contact between the Stockton Formation and the Palisade Diabase. Stockton beds dip at 15° NW while the irregular contact dips at 60° NW. This contact is locally welded according to Darton (1890) and Lewis (1908). This is one exposure where the Palisade Sill is described as having a dike-like appearance. Actually, these exposures and similar ones nearby are perhaps better explained by a local stepping up of the Palisade Sill as shown in Figure 26.

Stockton / Palisade Sill contact
Contact of uppermost Stockton with Palisade Sill directly on right (east). Stockton dips 15° NW and the contact dips 45° to 80° NW. This appears to be a continuation of the contact surface exposed at the Penn Central tunnel previously described. Recrystallized arkose of Stockton Formation is sheared and dragged upwards close to contact with fine slickensides indicating down-dropping to the west. There are no indications of movement in the diabase, however. Basal Lockatong hornfels 100 m to the north, dip 15° NW and lie concordantly on the Palisade Sill. A possible interpretation of these exposures might be that the apparent movement in the Stockton occurred during intrusion of the sill.

Dip slope of Palisade Sill
Dip slope of Palisade Sill mantled by northwesterly dipping Lockatong Formation. Contact appears concordant from here to Granton Quarry.

STOP 1. Abandoned Granton Quarry
Abandoned Granton Quarry in lower Lockatong Formation hornfels and overlying Granton Sill. Turn left off Route 1 and 9 into parking lot for Shop-Rite employees at Diana Stores Corporation.
Eleven Lockatong cycles are exposed on the sill-capped hill: seven are exposed on the south facing exposure (Figure 27); three additional cycles are exposed on the east facing exposure; and all 11 cycles are exposed on the north facing exposure but are not accessible without special permission. The base of the section appears to be 38 - 46 m above the contact with the Palisade Sill (Van Houten, 1969). This contact may be following what was, prior to intrusion, the Stockton-Lockatong contact.
According to Van Houten (1969) these Lockatong hornfels include calc-silicate varieties in the middle carbonate-rich part, and extensively feldspathized and recrystallized diopside-rich arkose in the upper part. Some beds of arkose show well developed crossbedding (Figure 28). Because of the buff arkose at the top of nearly every cycle, these are the most visually graphic of the detrital cycles seen on this field trip; here the many correlated changes occurring though individual cycles can be easily seen (Figure 29).
Cycles 3 and 7 (Figure 29) have produced representatives of all the known (skeletal remains of) Lockatong holostean Semionotus, and the amphibian Eupelor. The basal portions of division 2 of both of these cycles have extremely high densities of fossil fish, especially the coelacanth Diplurus newarki Schaeffer (1952). Small reptiles are also surprisingly abundant (Figure 30). Many important fish and unique reptile skeletons have been discovered here by dedicated amateurs, and donated to various museums through the years (Colbert, 1965, 1966; Schaeffer, 19S2; Schaeffer and Mangus, 1971; Colbert and Olsen, In Prep.; Olsen and Colbert, In Prep.).
At the south-facing exposures, cycles 1 and 2 are broken and injected by diabase of Granton Sill (Van Houten, 1969). Notice the absence of prominent folding at the diabase-sediment contact. The total thickness of the sill is 20m.
One or two bedding plane thrust faults, always thrusting to the east, are present in division 2 of nearly every cycle at Granton Quarry, Slickensides are usually present and indicate that movement occurred parallel to dip. All joint sets are cut by these thrusts, their displacement indicates each fault has a net slip of .5 to 1.5 cm. This type of minor thrust fault is evident in virtually all Newark Supergroup lacustrine cycles and can be seen at every stop of this trip.

Lockatong hornfels and Palisade Sill
Cloverleaf at this intersection rests on Lockatong hornfels and Palisade Sill (Fluur, 1941).

Open cut for Route 495 in Palisade Diabase.
Construction of cut exposed a number of easterly down-dropping dip slip faults which were described by Fluur (1941).

Reentrant in Palisade Escarpment
Reentrant in Palisade Escarpment at this point created by differential weathering along a series of dip slip faults, the cumulative dip slip amounting to about 70 - 80 m.

One of the larger faults
This street parallels one of the larger faults, in this case one responsible for the abrupt truncation of the western portions of Kings Bluff directly to the left (east) (Flurr, 1941).

Small fault striking nearly E-W.
According to Fluur (1941), construction along this road revealed a small fault striking nearly E-W.

STOP 2. Kings Bluff, Weehawken.
East face of Palisade ridge with exposures of long series of Lockatong cycles, tongues of Stockton-like beds, and alternating concordant-discordant contacts with the Palisade Sill. Park in lot on west side of road near the railroad tracks.
This is the first of three stops designed to show the lateral continuation of individual detrital cycles and the lateral change in sedimentary and metamorphic facies.
Lockatong and Stockton sediments and their contacts with the Palisade Sill are exposed at numerous places along the Palisade escarpment from Hoboken, New Jersey to Haverstraw, New York. Study of these exposures is permitting a cycle-by-cycle correlation of the Lockatong for at least 15 km of this distance, the cycles mapped so far are designated informally in Figures 31, 32, and 33. To the south at Hoboken the Palisade Sill rests near the base of cycles 5 and 6 (Figure 31). To the north towards the Lincoln Tunnel Toll Plaza, the contact drops more than 250 m into the Stockton Formation. At Kings Bluff, this contact abruptly rises again to cycle 0, staying within division 2 of this cycle for at least 300 m north. The olivine zone of the Palisade Sill produces an obvious bench along the escarpment, essentially paralleling the lower contact of the sill as observed by Walker, 1969 (Figure 31).,
Note the thin sill which branches off from the main sill intruding between cycles a and b. This sill definitely runs north for at least 400 m and was encountered during the excavations for the ventilation buildings for the Lincoln Tunnel (Figure 31) (Fluur, 1941). It may go at least another 200 m (Figure 36).

STOP 3. Gorge and River Roads
Gorge and River Roads exposures of cycles 1' - 6 and a and b. Turn right into empty lot outside entrance for Celotex Corporation.
Cycles 1 - 6 exposed along Gorge Road and cycles a-c on west side River Road opposite Mobil Service Station (Figure 37). These are the same cycles seen at Stop 2. Cycles 5 and 6 are virtually unchanged with the exception of an increase in ostracod density in the upper parts of division 2 of both cycles, fewer fish in division 2 of cycle 6, minor color changes, and the presence of calcareous nodules in division 2 of cycle 5. Cycles 1,3, and 4 appear unchanged from Stop 2, while cycle 1' is less disturbed and cycle 2 has more fish than at Stop 2.
In contrast with the relative lack of change from Stop 2 in cycles 1'-6, the siltstone units between cycle 6 and cycle a (Figures 32 and 33) are nearly completely replaced by 5.5 m of arkose with cross-bedding indicating transport to the west and southwest (Van Houten, 1969). I believe this arkose tongue and the thin siltstones present in this interval at Stop 2 to be the lateral equivalent of chemical cycles present in the central Newark Basin. Cycles a and b appear virtually the same as at Stop 2.
The detailed correspondence between beds and vertical changes in lithology and paleontology in cycles 5 and 6 (Figure 38) between Stops 2 and 3 is illustrative of the large area over which the factors responsible for the details of the cycles operated. The region represented by stops 2 and 1 was evidently far enough from shore (during the deposition of division 2) that the normal heterogeneous depositional environments of the shore had virtually no influence on cycles 5 and 6. This, in turn, is indirect evidence that the size of the lake which produced cycles 5 and 6 was considerably larger than the 15 km traced so far.
Note that Gorge Road follows fault-line ravine north of Lockatong exposures; eastern block is downthrown about 53 m (Van Houten, 1969).

Large xenoliths exposed on left (west)
Large xenoliths exposed on left (west) in excavation behind Virginia Lee Lace Co. (Van Houten, 1969).

Passing over eastern portal of tunnel
Passing over eastern portal of tunnel for former New York Susquehanna and Western Railroad. Directly under bridge for River Road is complete section of Lockatong cycles 1 '-6 and a. This same section is then repeated by a fault striking north. Cycle 2 is unusually fossiliferous, producing large numbers of well preserved Turseodus and fragmentary large Diplurus. At west portal of tunnel is a large open cut in upper Stocton and lower Lockatong. Contact with sill dips 65° NW while Stockton and Lockatong dip 15° NW.
These exposures appear to be a repeat of the pattern seen at mileages 13.6 and 14.3 as shown in Figure 26.

Old quarry on left
Old quarry on left with excellent exposures of cycles 4 - f and underlying Stockton Formation. Small fault exposed at back of quarry which drops down the western block.

Series of outcrops along abandoned trolley route
Up hill on left on west side of Undercliff Avenue is long series of outcrops along abandoned trolley route (Van Houten, 1969). Exposures include upper Stockton Formation and lower Lockatong including cycles 5 and 6 and a, b, and c. The base of Palisade Sill is well exposed with large xenolith of cycle 5 suspended about 5 m above Lockatong-sill contact. Cycle 5 below contact contains scapolite-aegirine and Na-feldspar hornfels, while xenolith of same unit consists of very course grained biotite, Na-feldspar hornfels with minor pyroxenes, and beds of cordierite, biotite Na-feldspar hornfels (Van Houten, 1969).

Large phytosaur skeleton
A significant portion of a large phytosaur skeleton was found in upper Stockton beds near here in 1911. The skeleton, named Rutiodon manhattanensis by Friedrich von Huene (1913), is not generically determinate because it lacks a skull.
Reentrant in Palisade escarpment at this point is due to a few east dipping normal faults.

Olivine zone of Palisade Sill on left.
Diabase below olivine zone has distinct laminated appearance.

Contact of Palisade Sill with Lockatong Fm.
Irregular contact of Palisade Sill with Lockatong Formation -stratum uncertain (Figure 39).

Lockatong-sill contact
Additional exposures of Lockatong-sill contact on left - largely conformable. On the right, at the base of the hill, is a foot path along which are exposures of buff arkose and red and purple siltstone of the upper Stockton Formation. These are the most southerly exposures of a facies of the Stockton Formation visible along the Hudson from here to Haverstraw, New York (Olsen, Baird, Selden, and Salvia, In Prep.).

Circle in park road at base of shear face of Palisade Sill.

STOP 4. Ross Dock, Palisade Interstate Park
Lunch and extensive exposures of cycles 1' - 6 and a - c and irregular lower contact of Palisade Sill. Park in lot, have lunch, then take stone steps up hill (west) to road at level of circle (River Road of park) and walk north along road to exposures of Lockatong (Figure 40).
Proceed north along road, slowly walking down section (Figures 40 and 41). Cycle 1' and overlying 4 m of arkose with no sign of cycle 0 which presumably pinched out or was cut out south of here. Cycle 1 is present but poorly exposed. Cycle 2 is very well exposed and contains the same fossils as at mileage 24.8, although there are fewer whole Turseodus. Cycles 3 and 4 are evidently replaced by buff, crossbedded arkose. Cycles 5 and 6 very well exposed. Middle part of division 3 of cycle 6 contains distinctive nodular calcareous bed resembling caliche. Cycle 5 still shows the same basic sequence of beds and vertebrates as previous stops, but cycle 6 is noticeably coarser with fewer less well laminations and there are less fish. Upper division 1 of cycle 6 has produced a partial arthropod of uncertain relationships about 20 cm long.
The tongue of buff arkose between cycles 6 and a is thinner than at Stop 3 and coarsely crossbedded. Lower arkose cuts down into cycle a at this exposure, eliminating its division 2 (Figure 42). Mean paleocurrent vector for these crossbeds is N 59° W (based on 8 readings).
Cycle a is penetrated by numerous Scoyenia burrows (which were definitely not present at mileage 26.3) as are what appear to be cycles b and c. We are clearly in the shallow water facies of division 2 of cycles a - c at this point but only just leaving the deep water facies of division in cycles 2, 5, and 6.
Cycle a shows well developed fracture cleavage in division 1. Cleavage dips 25° to 30° and strikes S 78° W. Cleavage is strata-bound but discontinuous, passing laterally into breccia or non-cleaved beds. What is the significance of these structures?
The facies trend in the Lockatong from Stops 2, 3, and 4 is from a more central basin facies to a marginal facies. The monotony in horizontal continuity gives way laterally to heterogeneity (Figures 33 and 38). Those cycles with the best developed microlaminae and the best preserved fish at Stop 2 are also those which persist the longest with the least change.

Towaco Formation
Proceed on Route 46 west over broad flat expanse of Towaco Formation mantled by Pleistocene and Recent deposits.

Type section of Hook Mountain Basalt is on right
Type section of Hook Mountain Basalt is on right (north) in cuts for Hook Mountain Road and Route 80. Pass into Boonton Formation.

Buried portion of Hook Mountain Basalt
In this area we cross back over buried portion of Hook Mountain Basalt which links up Riker Hill and Hook Mountain (see Olsen, this Fieldbook).

Contact between Towaco Fm and Hook Mountain Basalt
Excellent exposures on left (east) of contact between Towaco Formation and Hook Mountain Basalt in Nob Hill Apartment complex (former east half of Roseland (Riker Hill Quarry). Two flows of Hook Mountain Basalt visible here (cumulative thickness 110m).

Follow along the back slope of Riker Hill.

STOP 5. Geology Museum, Walter Kidde Dinosaur Park
Geology Museum and Walter Kidde Dinosaur Park (former west side Roseland (Riker Hill) Quarry). Park in lot and look over exhibits at Geology Museum. Then take access path from Geology Museum over the crest of Riker Hill and down, through wooded area into Dinosaur Park. Always get permission before entering park.
As it stood in 1975, the Roseland Quarry occupied 55 acres, exposed 95 m of upper Towaco Formation - including two complete Towaco cycles, and exposed about 50 m of the overlying Hook Mountain Basalt (Figures 43 and 44). The quarry became very well known in the late 1960's and early 1970's for its prolific dinosaur footprints. Because of the scientific and educational potential of the site the then owners, Walter Kidde and Co. Inc., donated the most productive 15 acres to the Essex County Park Commission. The site now awaits development.
Before the other 40 acres were developed as the Nob Hill development, the following features could be seen:
1 , lateral changes in facies within divisions 1 - 3 of the lower cycle (Figure 45). The microlaminated beds of division 2 produced many fossil fish, all Semionotus (Figure 46) as did a number of the thinner (30 cm) turbidites.
2 , two upwards coarsening turbidite sequences, the lower being by far the larger (Figure 45). The lower sequence shows large scale slumped beds resembling "wild flysch" associations. Some of the "roll over" structures are 2 to 3 m in diameter. Transport was from the east.
3 , abundant dinosaur footprints in possible crevasse splay (in division 3) of channels about 70 m to north of tracks (Figure 47). Orientation of trackways proved to be parallel to paleocurrent directions derived from ripple marks within the footprint-bearing bed and oriented plant debris in overlying beds.
4 , Series of 7 fining-upwards cycles of division 4 of the lower Towaco cycle in the Quarry. Middle3 cycles had extensively developed dolomitic nodules and deeply mudcracked beds. Second fining-upwards cycle from the bottom with laminated silty beds (?flood basin) with abundant clay filled root casts, many of which are surrounded by dolomitic nodules (Figure 48).
In the presently exposed beds the following can be seen:
1, uppermost fining-upwards cycle of lower Towaco cycle still exposed along eastern boundary of park. The upper and middle parts of this cycle have the best reptile footprints in the quarry and hold the key to the park's development. Footprints are especially abundant in interbedded sequences of possible crevasse splay sandstone and flood basin siltstone. Basal sandstone portions of cycle are locally deeply down cut into underlying beds and contain beds of mud-chip conglomerate and casts of tree limbs and roots. Uppermost portions of the cycle consist of fine siltstone transitional into the lower parts of division 1 of the upper Towaco cycle. Transitional beds with numerous red siltstone roots surrounded by greenish halos.
2, exposure of complete Towaco cycle. Division 1 contains prominent fine sandstone beds with large calcareous concretions which weather out to form limonite filled cavities and extensive large (1-4 cm) coalified roots which probably belong to conifer trees. Crevasse splay beds in division 1 covered with little dinosaur footprints. Identical beds occur in division 2 of this cycle exposed in Chatham, New Jersey, 13 km south of here.
3, microlaminated portion of division 2 has very well developed white-black microlaminae (Figure 15) - but no fish have been found yet, however. Upper parts of microlaminated beds contain distinctive nodules of black chert. Black, coally-looking siltstone surrounding chert bed has several bedding thrusts similar to those seen in the Lockatong at Stops 1 - 4. Microlaminated beds locally involved in disharmonic folds (Figure 15). Like the beds of division 1, these portions of division 2 look exactly the same in the Chatham exposures.
4, casts of a salt present in coarse siltstone beds above microlaminated portion of division 2.
5, massive fine gray siltstone in upper parts of division 2 have well-preserved conifer foliage, pollen and spores, individual fish scales (Semionotus), and rare insect fragments.
6, complex series of sandstones and siltstones of division 3 showing features suggestive of both laterally migrating channels and prograding deltas.
7, lowest fining-upwards cycle in division 4 (Figure 49) shows slip-off faces of point bar and beds of intraformational conglomerate with coprolites, fish scales, reptile bone fragments, and abundant dinosaur footprints. The latter features could represent a dinosaur "wallow".
8, 10 successive fining-upwards cycles of division 4. Rill marks very well developed in bank portions of one of the middle cycles (Figure 50) These sorts of rill marks, typical of channels with rapidly dropping water levels, have long been confused with plant remains (it is easy to see why) and have received the name Dendrophycus (Newberry, 1888).
9, unique small reptile footprints with structure highly suggestive of advanced mammal-like reptiles or mammals (Figure 20) are present in upper fining-upwards cycles. If they do represent mammals,they will be the oldest North American record.
10, very badly weathered "tuff" between normal Towaco Formation and Hook Mountain Basalt. This unit is enigmatic but very widespread at this stratigraphic position. Fresh exposures were described by Lewis in 1908 (see Olsen; this Fieldbook).

Preakness Mountain Basalt
Head east on 280 up dip slope of Preakness Mountain Basalt. Outcrop width of Preakness Basalt is very large in this area, suggesting a thickness of 500 m for the basalt. I believe this is due to a number of small strike faults and the true thickness is closer to 300 m. These faults in combination with the multiple flow character of the Preakness Basalt produced the many small ridges visible while driving up the dip slope.

Type section of the Preakness Basalt
Type section of the Preakness Basalt in deep open cut for Route 280. Section exposes about 100 m of the lower flow. Note distinctive "splintery" nature of the lower 50 m (see Olsen, this Fieldbook). This section is cut by a series of faults all apparently left lateral and all showing little or no apparent dip slip offset (Figure 51).

Preakness Basalt / Feltville Fm contact
Contact between Preakness Basalt and Feltville Formation poorly exposed on south side of road.

Unexposed contact
Unexposed contact between Feltville Formation and underlying Orange Mountain Basalt below this point.

Exposures of ?second flow of Orange Mountain Basalt.

Type section of Orange Mountain Basalt
Type section of Orange Mountain Basalt in very long and deep open cut for Route 280 (see Olsen, this Fieldbook; Manspeizer, this Fieldbook). Section exposes about 55 m of lower flow as well as a number of left lateral faults similar to those seen at mileage 64.8. Left lateral faults are present here as they are at mileage 64.8. At one portion of the cut, on the north side is 20 m long horizontally slickensided fault plane. Note the very different appearance of basalt (in terms of jointing) from the Preakness Basalt.

Contact Orange Mountain Basalt / Passaic Fm
Contact of Orange Mountain Basalt and Passaic Formation was well exposed during construction of this cut, at this point.

Triassic-Jurassic boundary
Cuts in uppermost Passaic Formation here have produced phytosaur footprints called Apatopus and the possible crocodillo-morph tracks called Batrachopus. The Triassic-Jurassic boundary lies somewhere within the upper few tens of meters of the Passaic Formation here.

Passaic Formation formerly exposed here
Sedimentary cycle in Passaic Formation formerly exposed here. A very well preserved palynomorph assemblage recovered from fine gray siltstones of this unit suggest a lower Rhaetic age (Comet, 1977). This unit has also produced a series of reptile footprints including large and small Grallator and Chirotherium sp. Scoyenia is abundant as is the conchostracan Cyzicus. Equivalent beds are exposed at the same stratigraphic position in New Brunswick, New Jersey. The entire Passaic Formation section from this unit to the Orange Mountain Basalt is above the entire Delaware River section of the Passaic Formation, which extends upwards only into Norian beds (Cornet, 1977).

53RD ANNUAL MEETING 18-20 SEPTEMBER 1981
BINGHAMTON, NEW YORK
GUIDEBOOK FOR FIELD TRIPS IN SOUTH-CENTRAL
NEW YORK
Paul Enos, Editor
State University Of New York At Binghamton
Published by the New York State Geological Association. Guidebook available from the executive secretary: Manfred P. Wolff, Department of Geology, Hofstra University, Hempstead, New York, 11550.

A1: THE WEST FALLS GROUP (UPPER DEVONIAN) CATSKILL DELTA COMPLEX: STRATIGRAPHY, ENVIRONMENTS, AND SEDIMENTATION
James R. Ehrets
University of Rochester
Since the last meeting of the NYSGA in Binghamton (Coates, 1963), significant advances have been made in the refinement of correlation and environmental interpretation of Upper Devonian strata in south-central New York. One purpose of this article is to summarize the updated stratigraphy in this region and to review how the stratigraphy has been developed. The main theme of the article is the result of recent study in the Binghamton area (Fig. 1). By tracing thin units of dark-gray shale to the east of Binghamton, a stratigraphic framework was developed which permitted further analysis of environmental and sedimentologic relationships of the Catskill delta complex in the area. Through the demonstration of the dark-shale framework and discussion of deltaic environments, a few of the interpretations are presented. The accompanying field trip is designed to illustrate a variety of deltaic environments and how they fit into the stratigraphic framework.

A1: THE WEST FALLS GROUP (UPPER DEVONIAN) CATSKILL DELTA COMPLEX: STRATIGRAPHY, ENVIRONMENTS, AND SEDIMENTATION

STOP 1. Distal Platform.
(Field locality 4) The relatively thin beds of fine-grained sandstone interbedded with gray shale are characteristic of middle- and distal-platform environments. Sandstone beds of approximately one foot in thickness have basal coquinites 1-2 inches thick; thicker sandstone beds have basal coquinites up to one foot thick. The coquinites are typically composed of disarticulated and articulated brachiopod shells with significant numbers of crinoid columnals. Some sandstone beds are graded coarse-to-fine. The shales are generally not very fossiliferous, but localized areas of bedding planes can produce quite a few well-preserved brachiopods and molluscs. A zone of large pillow structures is distinctly visible near the top of the exposure. The zone is laterally persistant for the length of the exposure. These pillows (denoted as type I) are composed of fine-grained sandstone; the distorted matrix of shale in which they are situated suggests that these structures formed as a result of vertical foundering. Smaller, solitary pillows are present at the base of the exposure near the parking area. These are denoted as type II pillows and are probably formed in a similar manner as type I pillows.
This portion of the platform was well-removed from the effects of rivers and streams. Sand which reached this area was supplied in the form of "sheets" from distributaries, which had merged with each other closer to the shoreline. Grading in the sandstones as well as the presence of basal coquinites indicates a "proximal turbidite" origin.

STOP 2. Dark Mud And Proximal Platform Environments.
(Field locality 7) The dark-gray and rust-brown mudstones and shales of the Roricks Glen Member are exposed in the basal portion of this exposure. Outcrops of the Roricks Glen on the delta platform are all about 20 feet thick and are composed predominately of mudstone with smaller amounts of shale. Thin-bedded lenses of fine-grained sandstone and siltstone are present in the dark-shale member; fossils are few in number. Flagstones and sandstone lenses near the top of the exposure indicate a return to normal deltaic conditions. The large block of cross-bedded sandstone at the very top of the bank (although slightly dislodged) is of channel origin in what is inferred to be the subaqueous delta plain. Cross-bedded sandstone is present in the form of scattered blocks on the hillside above the roadside exposure. The Roricks Glen will be seen again in a similar environmental association later in the field trip.

View of Susquehanna River Valley.

STOP 3. Subaqueous Delta Plain
(Field locality 18). The flagstone deposits in the quarry are typical of the subaqueous delta-plain environment. The large-scale crossbedding in the south wall of the quarry is evidence that this portion of the delta plain is gradational with a.distributary-mouth bar within the delta platform. This interpretation is supported by a nearby shale pit which exposes normal delta-platform deposits. Current and wave ripples, low-angle crossbedding and parting lineations are common sedimentary structures at this locality. Orientations of the structures indicates a southwesterly average current direction. With the exception of oriented plant fragments on a few bedding planes, fossils are rare.

STOP 4. Proximal Platform
(Field locality 42). The numerous lenses of sandstone exposed here are subaqueous extensions of distributaries which flowed westward from the subaqueous delta plain. Near the base of the exposure on this road is a zone of organic-rich sandstone that is interpreted to be the result of a rapid regressive (storm) event which interrupted normal progradation of the deltaic environments. A thin stringer of quartz-pebble conglomerate is associated with this sand deposit. This conglomeritic horizon has been found to exist elsewhere in the study area to the west. In addition to a variety of ripple marks which can be observed on the terraces in the upper portion of the outcrop, a lens of large pillow structures and a variety of crossbedding are among the more obvious sedimentary structures.

STOP 5. Proximal Platform And Subaqueous Delta Plain
(Field locality 49). The interbedded flagstones, cross-bedded sandstones, and shales in this exposure illustrate the variety of lithologies which coexist at the margin of the subaqueous delta plain. The beds and lenses of sandstone are small distributary-mouth bars formed as a result of the reworking of sand at the fronts of streams. The relatively dark shale was deposited behind the bars in restricted waters of small bays. Cross-bedded, organic-rich sandstone lenses are the remains of distributaries which migrated laterally in this region. The bar deposits gradually give way to subaqueous delta-plain channel deposits which are composed of more poorly sorted, cross-bedded sandstone. Higher up in the exposure is a 10-foot thick bed of dark shale and mudstone which is correlative with the Roricks Glen Member. This fine-grained deposit grades upwards into drab-colored overbank deposits of the subaerial delta plain.

STOP 6. Subaqueous And Subaerial Delta Plain
(Field locality 46). The extensive exposure in this quarry (formally called the Ostrander quarry) displays a variety of flagstone and cross-bedded sandstone of stream origin within the delta plain. Ripple marks and scour marks are very common on the surface of terraces in the quarry. Burrowed and mud-cracked mudstone forms the floor on the second terrace (west face of mountain). These and similar deposits in the quarry are of floodplain origin. Red-orange, conglomeritic debris scattered around the area are levee deposits which can be seen in place as lenses associated with channel sandstone in the quarry walls. A thin red bed is visible about two thirds up the sheer face on the western wall. Just above the red bed (one of only a few in the study area) is a dark-shale bed that is correlative with the Roricks Glen Member. A thin coquinite at the base of the overlying sandstone bed contains shell material left as a lag deposit resulting from winnowing of the very top of the Roricks Glen.

STOP 7. Distal Platform
(Field locality 35). The conspicuous zone of extremely large pillow structures in the lower section of the quarry is a feature which is cnaracteristic of the distal platform environment. These pillows are referred to as type III and are interpreted to have formed due to repeated foundering of relatively coarse platform sediments which were continually supplied to submarine topographic lows by the reworking effects of waves and currents at the edge of the platform. The mudstone and siltstone matrix of the pillows contains a random distribution of small fossil material consisting mostly of crinoid columnals. The matrix as a whole displays a weak cross lamination in places. The number of lenses and thin beds of sandstones increases upsection indicating the westward progradation of the shoreward environments. Basal coquinites are common in these sandstones. (The top of this section, which is exposed along Farm-to-Market Road at the top of the hill, contains a horizon of dark shale within the Dunn Hill Member).

STOP 8. Distal Platform And Dark Mud Environments
(Field Locality 11). Once again, the presence of extremely large (type III) pillow structures indicates the distal platform environment. Here, the pillows are resting upon and within the Dunn Hill Member. The pillows are compositionally similar to those at STOP 7. Currents on the delta platform were active during the deposition of the Dunn Hill as evidenced by these relatively "coarse-grained" structures as well as lenses of sandstone which display crossbedding. Although not shown here, deposits of fossiliferous, cross-bedded "delta-front sands" can also be fairly well developed only a few feet above a given dark-shale member. Thus, a normal deltaic environments rapidly redeveloped after transgression.

A2: THE MIDDLE AND UPPER DEVONIAN CLASTIC WEDGE IN NORTHEASTERN PENNSYLVANIA
W. D. Sevon
Pennsylvania Geological Survey
Harrisburg, Pennsylvania 17120
Throughout most of the Paleozoic, much of what presently constitutes the eastern half of North America was part of an inland sea which intermittently received clastic sediment from an eastern source area. The Appalachian basin was the central focus of this sedimentation.
The largest integrated wedge of clastic sediment in this basin was deposited by the Catskill delta system during the Middle and Late Devonian. The purpose of this paper is to present an overview of Late Devonian sedimentation, with particular reference to Pennsylvania. The purpose of the field trip is to examine some of the rocks from which interpretations about the Catskill delta system are made. The information presented here derives from the literature as well as my own work. The term "delta system" as used here refers to multiple contiguous deltas operating in the same sedimentary basin at approximately the same time. The Catskill delta system is also a tectonic delta complex in the sense defined by Friedman and Johnson (1966, p. 185-186) for New York State and used by Humphreys and Friedman (1975, p. 369-370) in Pennsylvania: "a deltaic complex built into a marine basin contiguous to an active mountain front and dominated by orogenic sandstone derived from the nearby tectonic highland."

A2: THE MIDDLE AND UPPER DEVONIAN CLASTIC WEDGE IN NORTHEASTERN PENNSYLVANIA

STOP 1. Prodelta Environment
Rocks at this stop are exposed in an outcrop along the west side of the road and along the west side of the stream below road level. Stream elevation is 970 feet.
The rocks exposed here comprise dark-gray shales and siltstones of the Lock Haven Formation. The siltstones have sharp bases, overlie shales, and fine upwards into shale. Burrow traces and fossils of marine invertebrates occur. Lateral continuity of beds is good within the extent of the small outcrop.
This is a good problem outcrop. If examined as an isolated entity, how much information can be gained from the outcrop itself? How much does it help to know the relative position of the outcrop in the vertical sequence of Figure 7? How important is context in the study of (1) rock lithology, (2) depositional environment, (3) stratigraphy, and (4) geologic history?

STOP 2. Marginal-Marine Environment
The flagstone quarry at this site was opened into rocks of the lower part of the Catskill Formation. The flagstone derives from the planar-bedded sandstones exposed in the floor of the quarry at elevation 1660 feet. The sequence of lithologies exposed here (Fig. 9) is interpreted to represent deposition in an offshore bar environment and the following information about the stop is from Krajewski and Williams (1971b, p. 13-15) .
"Characteristics of this type of quarry include:
a) a convex upper surface;
b) parallelism of the parting lineation orientation and the down-dip direction of the cross-bedding;
c) a steep front in the seaward direction;
d) replacement seaward (northwestward) by darker, fossiliferous, marine shales;
e) replacement landward (southeastward) by siltstones, small scale rippled sandstones, and red shales; and,
f) uniformness and regularity of the joint systems (the high walls of the quarry parallel the joint systems).
"Two offshore bars are visible in the diagram, the larger lower one, and another smaller one in the south end of the quarry. The long direction, or paleogeographic trend, of these bars would be perpendicular to the parting lineation shown in the diagram, or northeast-southwest and east-west for respectively the lower and upper bars. The rock sequence represents a marine transgression onto the tidal flats and shore zone."
Examine this stop with the following questions in mind: (1) How easily can the depositional environment be determined from the physical properties of the rocks? (2) Does the interpretation of this outcrop aid in the interpretation of the rocks at Stop 1? (3) What information can be gained about the source area from this stop?

STOP 3. Fluvial Environment
Pull off and park on wide berm at south end of road cut and examine the rocks along the terrace above the road.
The rocks at this stop are exposed in the southernmost of three large roadcuts on the west side of Interstate Route 81, all of which expose similar rocks. Elevation here is 1640 feet.
Exposed here are a variety of sandstones, both gray and red, which contain lag gravels, cross beds, planar beds, and ripples (Fig. 10). Interbedded red siltstones are locally burrowed. Lag gravels comprise predominantly calcium-carbonate nodules. Cross-bed foresets are oriented mainly to the southwest while parting lineations are to the northwest. Lateral and vertical relationships are complex, but the whole can be interpreted in terms of a fining-upward cycle formed by a meandering stream (Allen, 1970).
What features of this outcrop are critical to the interpretation of its depositional environment? How many levels of context are involved in studying this outcrop? What information about the source area can be gained from this outcrop?

STOP 4. Nay Aug Park - Lunch
This stop is principally for the purpose of ingesting food, but some interesting things can be seen.
The Brooks Model Coal Mine area has the entrance to an underground anthracite mine and some old coal cars. The sandstones exposed throughout the park are part of Llewellyn Formation of Pennsylvanian age. This formation contains a number of anthracite coal seams which have been mined, principally by underground methods, in the Wyoming-Lackawanna basin (the northern anthracite field). Exposures along the railroad track along the east side of the park allow evaluation of the depositional environment of the rocks exposed here.

Basal Pottsville Formation conglomerate.
Outcrops on both sides of road of basal Pottsville Formation conglomerate. Outcrop to left is upper part of Stop 7.

To right across Roaring Branch is dip slope
Outcrop to left is Spechty Kopf Formation and site of start of Stop 7. To right across Roaring Branch is dip slope underlain by Spechty Kopf Formation sandstones. Shale exposed below sandstone.

STOP 5. Fluvial Environment
The rocks at this stop are exposed in cuts on both sides of Interstate Route 84 east at the point where entrance ramps from Interstate Route 380 east and west join. Park on wide berm on the south side of the road and examine the rocks in the cut on the north side of the road. Cross the interstate with care!
The rocks exposed here are near the uppermost part of the Poplar Gap-Packerton Member of the Catskill Formation (Fig. 8). The sequence (Fig. 11) comprises mainly gray sandstones with some red mudstones. Sandstone and siltstone contacts are sharp. The gray sandstones are cross bedded, contain some lag gravels, and are locally calcareous (calcareous cement weathers brown). Scattered red-shale clasts are common near the bases of some sandstone bed sets. The lag gravels contain some quartz pebbles, but mainly calcium-carbonate nodules, many of which look like oncolites. Root traces occur locally in the sandstones.
The lower red mudstone is burrowed in part and contains abundant calcium-carbonate nodules. Note the thinly laminated character of some of the mudstone enclosing the nodules.
There are many questions to be asked about these rocks. Would information on context be useful in making an environmental interpretation? What information can be gained about the source area? Is source-area information at this outcrop more or less abundant than at Stop 3? What is the significance of the presence of calcium carbonate? How were the calcium carbonate nodules formed in the red mudstones and in the gray sandstones? What is the evidence for a fluvial origin for this sequence? What specific fluvial environment best fits these rocks?

STOP 6. Fluvial Environment
The rocks exposed here are near the lowermost part of the Duncannon Member of the Catskill Formation (Fig. 8). The rocks comprise one complete and two partial fining-upward cycles (Fig. 12). Two cycles have a sharp base with gray sandstone overlying red mudstone. Above the base there is an upward decrease in grain size from sand to clay and change to red color.
The lower sandstone has some calcium-carbonate cement, a few root traces, and bedding changes upward from crossbedding to planar bedding. The overlying red mudstones contain repeated zones with abundant burrows and root traces. The mudstone between these zones is generally thinly laminated. The upper third of the lower major cycle is a smaller cycle which has a grayish red sandstone above a sharp base. Calcium-carbonate nodules are abundant in the mudstone below the sharp base of the upper major cycle. Several large channel cuts occur in the gray sandstone of the upper cycle.
What is the probable origin of the excellent fining-upward cycles displayed in this exposure? How do these cycles compare with that at Stop 3? What is the significance of the alternating burrowed and nonburrowed zones in the mudstone? How do the calcium-carbonate nodules in the red sandstone compare with those at Stop 5? What differences in depositional environment are suggested by the differences in the rocks exposed here and at Stop 5? Is context of particular value in interpretation of the depositional environment of these rocks? What information about the source area do these rocks provide?

STOP 7. Spechty Kopf Formation And Local Subsidence
Park well off road on berm to right before guard rail starts and just after junction of entrance ramp to Interstate Route 380 west. Bus will proceed 0.8 farther to end of upper outcrop for pickup.
This stop occurs at roadcuts on the east side of Interstate Route 380 just south of Dunmore and consists of two parts: a long, high roadcut just north of the entrance ramp (lower outcrop) and a long, low roadcut about 0.7 miles farther north (upper outcrop). The exposures are separated by a covered interval.
The identification of the rocks at this stop is different from that indicated on the 1960 edition of the geologic map of Pennsylvania (Gray and others, 1960), but is in agreement with the 1980 edition of that map (Berg and others, 1980). The changes result from the work of Sevon (1969) and subsequent reconnaissance mapping. The Pocono Formation occurs in the covered interval between the lower and upper exposures.
The lower outcrop (Fig. 13) consists of dark shales and sandstones of the Mississippian-Devonian Spechty Kopf Formation. The shales are here about 300 feet thick and are underlain (in exposures along Roaring Branch) by polymictic diamictite. Interbedded thin siltstone layers exposed in the lower third of the shale in the former Nay Aug quarry across Roaring Branch have bottom-surface flow structures and upper-surface ripples which indicate current flow of N12E. Very large and relatively small slump structures occur in the upper third of the shale and are very well exposed here. The contact of the shale and sandstone is gradational through a zone of interbedding. A zone of load casts occurs just below the first sandstone interbed.
The sandstone comprises relatively uniform and moderately well-sorted grain size throughout, is very light gray in color, weathers tan, and is about 160 feet thick. Bedding in the lower part defines wedge-to-irregularly lens-shaped bed sets which dip northwestward at a steeper inclination than the overlying planar beds. The planar bedding is remarkably uniform and persistent. Some beds have ripples, but most are apparently structureless.
What are the environments of deposition of the rocks exposed in this outcrop? The rocks underneath the basal polymictic diamictite are those of the Duncannon Member seen at Stop 6. Does this aid or complicate the interpretation? Also of importance is the fact that 5 miles to the north on the other side of the basin, this sequence is compressed to 110 feet in thickness and is totally absent along all margins of the basin within 20 miles of this locality. The unusual thickness of this sequence and its lateral variation is interpreted to indicate local subsidence at the time of deposition. The regional aspects of these facies (Sevon, 1969; 1979b) are interpreted as part of the demise of the Catskill delta (see earlier text).
The upper outcrop (Fig. 14) is capped by a white conglomerate of the Pottsville Formation of Pennsylvanian age. The conglomerate is underlain by a sequence of siltstone, sandstones, and limestones which are unlike any other rocks at similar stratigraphic positions anywhere in eastern or central Pennsylvania. The sequence is correlated with the Mississippian Mauch Chunk Formation on the basis of stratigraphic position, but the rocks are very dissimilar from the red siltstones and sandstones which characterize the Mauch Chunk as near as 20 miles to the southwest. However, known facies changes along the southeastern margin of the Wyoming-Lackawanna basin and the abundance of calcium carbonate suggests that such correlation is valid. What environments of deposition may be represented by these lithologies--particularly the thin limestone? Do these rocks, including the Pottsville conglomerate, tell much about the source area?

A3: MIDDLE AND UPPER DEVONIAN SHALES AND ADJACENT FACIES OF SOUTH-CENTRAL NEW YORK
Brent K. Dugolinsky
State University College - Oneonta
GENERALIZED STRATIGRAPHY OF MIDDLE AND UPPER DEVONIAN SEDIMENTS OF NEW YORK
The Devonian section in New York is the standard reference section for eastern North America. Early workers recognized that major facies changes occur in the Middle and Upper Devonian sequence as a result of deposition of the Catskill delta. Consequently, older units originally mapped as formations or groups in a particular area were recognized as portions of major facies (Catskill, Chemung, Portage) cutting across time lines. Later workers concentrated on finding thin, widespread key beds within the thick deltaic sequence that are unaffected by rapid facies changes characteristic of rocks above and below. These key beds, which are believed to represent time planes, divide the deltaic sediments into several time-stratigraphic units.
The main purpose of this field trip is to observe the field relationships and subtle lithologic changes within and between the shales and adjacent facies in the "Catskill Delta" sequence and to interpret these characteristics in terms of the depositional environment. By the end of the trip, you should have a better understanding of why detailed mapping and identification of facies relationships remains complex and problematical in spite of exhaustive study by numerous workers for over a century.

A3: MIDDLE AND UPPER DEVONIAN SHALES AND ADJACENT FACIES OF SOUTH-CENTRAL NY

STOP 1. East Beecher Hill Roadcut, Owego, N. Y.
(Description partially from Woodrow and Nugent, 1963, and Patchen and Dugolinsky, 1979).
Exposures of Beers Hill and Roricks Glen Members of the Rhinestreet Formation. Elevation at bottom of exposure is 950'.
The Rhinestreet Shale defines the base of the West Falls Group from Lake Erie eastward to Seneca Lake. East of Seneca Lake workers at the University of Rochester under the direction of Robert Sutton have traced fingers of dark-gray shale that define the eastern Rhinestreet equivalent. In the area from Elmira to Binghamton, four dark shales and three intervening lighter colored shales and siltstones (including the Beers Hill Member exposed here) are defined as members of the Rhinestreet Formation (Sutton, 1963; Woodrow and Nugent, 1963).
The Roricks Glen is represented by scattered, very dark-gray shales at the upper end of the exposure. However, many of the darker shale layers have been covered and are difficult to locate. Also, the land above the roadcut is posted and it is therefore recommended that you limit your observations to the exposure along the road. Most of the exposure is in the Beers Hill Member, with flow rolls well developed in the section near the bottom of the hill, just above a landslide scar. Fossils are scarce, but worm burrows and trails (Fucoides graphica) are often found, particularly on the base of the thick, resistant coarser-grained beds. Flute casts, cross bedding and other current indicators are also found.

STOP 2. Richford, N. Y.
The base of the Middlesex Shale Member of the Sonyea Group may be seen exposed in the stream bed across the road from the parking area. The basal few feet of stream exposure is West River Shale, followed by brownish-black shale and siltstone of the Middlesex. Only a few feet are clearly exposed at this location.
Well-developed groove casts and burrows may be found on the base of silty beds. Most of a steep roadcut on the same side of the road as the parking area is covered, but a little digging will expose the Middlesex.
The Middlesex Shale gets progressively finer grained and darker farther west, towards the type section. This facies relationship is generally true for all Upper Devonian shale units.

STOP 3. Finger Lakes Stone Co. Quarry,
(Descriptions from Chute, 1970 and Dugolinsky, 1972)
The entire quarry exposure is within the Rock Stream Formation (previously named the Enfield Formation) of the Sonyea Group. Layers of sandstone alternate with layers of shale and siltstone. The Rock Stream has been interpreted as representing a shelf deposit (300-500 depth), although much shallower depths are likely. Its westward equivalent, the Cashaqua Shale, represents a slope and basin environments in deeper water.
Many of the silty and sandy beds pinch out rapidly. Fossils and sedimentary structures are very common and well developed. Sole marks may be best seen on the base of silty layers. Worm burrows are common. Excellent sole marks, including flute and groove casts, are usually most accessible on quarried slabs.
The quarry is presently operated by the Finger Lakes Stone Company. Slabs of sandstone are obtained without blasting by drilling holes on seams and separating them with wedges. The slabs are cut to the desired sizes in the mill by diamond and wire saws. Pieces with good joint surfaces are used for special surface effects. The stone is laid in various patterns with different finishes, as illustrated by the exterior of the company's office at the quarry.

STOP 4A. Railroad Cu
Railroad Cut Between Salt Company And Abandoned Cement Plant, North Of Ithaca
Exposure of the King Ferry Shale of the Ludlowville Formation.
About 25 feet of the King Ferry Shale is exposed here, with a noticeable dip to the south. Many concretions may be seen in the siltstone beds, which are lighter colored than the shales. The darker shales are commonly cross-laminated. A coquina (fossil-rich layer) is evident at the base and top of the siltstone unit.
Much of the unusual weathering characteristics of this exposure is thought to be due to salt contamination from passing railroad cars coming from the salt plant just to the north of the exposure.

STOP 4B. Gulf Stream (Shurger Glen)
Exposured are the upper King Ferry Shale, the Portland Point Limestone, Moscow Shale and Tully Limestone.
The upper King Ferry Shale of the Ludlowville Formation may be seen in the exposures in and below the lower falls in Gulf Stream. The overlying Portland Point Limestone, near the lip of the lower falls, is very fossiliferous. Note the peculiar curved fracture pattern in the shales just below the falls.
The lower falls may be scaled on the left side (facing upstream) with care, where the approximately 5 feet of Portland Point Limestone may be examined. The Portland Point is coarsely crystalline and weathers brown. Slickensides may be observed in the lower 8 inches of the member.
Float at the base of the lower falls includes samples of Tully Limestone, which is finer-grained and less fossiliferous than the Portland Point limestone.
The Moscow shales overlie the Portland Point and are roughly 100 feet thick in this area. They are well exposed upstream from the lower falls. A nearly complete exposure of the entire 100 feet may be seen about 5 minutes upstream. The overlying Tully Limestone is visible at the top of the cliff exposure and forms the lip of the upper falls which is about another 20-minute walk farther upstream. Dark shales (Geneseo) may be seen in the float below the upper falls and are probably exposed above the upper falls. There is excellent joint control in the stream at and immediately below the upper falls.
The gray silty shale and siltstones of the Ludlowville and Moscow demonstrate a high diversity fauna and represents sediments deposited in a subtidal shelf-delta platform (Grasso, 1978).

STOP 5. Buttermilk Falls State Park
A recent study (deWitt and Colton, 1978) has revealed that 14 feet of Renwick Shale are exposed at the base of the lower falls, overlain by 478 feet of Ithaca shales and sandstones, which in turn are overlain by 135 feet of West River Shale. The Renwick Shale is easily accessible here, particularly for large groups. Note the darker color of the shale with the interbedded lenticular silty beds exposed. The precise contact of the Renwick with the overlying Ithaca is not easy to pick out.
The Renwick here separates coarser-grained clastics: the underlying Sherburne and the overlying Ithaca Formation. Westward, the Renwick merges with the Penn Yan Shale, which is the lower of two shales in the finer western facies. A travertine deposit may be seen on the vertical exposures at the left of the main swimming pool (looking upstream). It is assumed that these deposits are very recent (post-glacial) and result from the deposition of materials in groundwater.

STOP 6. Taughannock Falls State Park
Park on left (before bridge) in Taughannock Falls State Park. Walk into gorge, using trail on the left bank.
(Descriptions from Cornell University Department of Geology, 1959, and from deWitt and Colton, 1978).
Note: At 215 feet, Taughannock Falls is the highest falls in North America east of the Mississippi River.
The main falls is at the head of a deep post-glacial gorge one mile long, with walls from 200 to nearly 400 feet high. The falls is determined partly by the superior resistance of the Sherburne sandstones and partly by the jointing pattern within the rock units. The upper 90 feet of the Geneseo Shale is exposed in the gorge walls from the level of the plunge pool to a point marked by a change in lithology and color. Much of the Geneseo is covered with talus in places. The entire Penn Yan (about 80 feet thick at this locality), the overlying Sherburne (also about 80 feet thick) and the Renwick Shale (about 35 feet thick) are exposed here, along with the lower portion of the Ithaca. At the mouth of the gorge, near the lake, is the lower falls (about 15 feet high), over the resistant Tully Limestone, (also about 15 feet thick here), between the weak basal Geneseo shales above and the shales of the Moscow Formation below.
Both the Sherburne and the Renwick facies are lost only about 15 miles west of this location, where they merge into the Penn Yan Shale.
Note particularly the interfingering nature of the contact between the Tully and the overlying Geneseo, easily seen in the stream bed above the lower falls. This indicates that although there may be an unconformity at the top of the Tully Limestone farther west, there is none here.
Joint control is well developed, particularly within the Geneseo Shale, and is best seen in the cliffs below the main falls and in the stream bed just below the main falls. Alnoite dikes, each less than one inch thick, are present in the stream bed beneath the main falls.
We are now on the northern flank of the Fir Tree Anticline and a slight northern dip may be seen easily if you look at the water flowing over the Tully Limestone, following a bedding plane, just above the lower falls where the stream bed is wide. En echelon fractures are well developed in the Tully Limestone exposed in the stream bed.
This gorge was used in pre-World War II days for sets in "western" movies and some of the wooden shacks precariously perched on the face of some of the cliffs were used to house the cameras during filming.

STOP 7. Fayette Town Dump
(Description partly taken from Cornell University Department of Geology, 1959).
This quarry was originally operated by the Town of Fayette for road material and is now used as a dump. The upper 40 feet of the Levanna Shale and lower 20 feet of the Centerfield Limestone are exposed here. The Levanna is the upper member of the Skaneateles Formation whereas the overlying Centerfield Limestone is the basal unit of the Ludlowville Formation of the Hamilton Group.
We have observed the upper of two general facies within the Hamilton Group at Stops 4-A and 4-B: The Ludlowville and Moscow Formations. Here, we can see a different gross facies represented by the dark, fissile Levanna Shale Member of the Skaneateles Formation, which represents an anaerobic, distal basin (Grasso, 1978). The overlying Centerfield Limestone separates this facies from the lighter colored, silty Ludlowville.
This is a good fossil-collecting site, particularly near the base of the Centerfield Limestone. Most common fossils are brachiopods, pelecypods, gastropods, plant fragment and fish remains. Mineral-filled fractures are common and asphaltic-filled fractures are occasionally found. Pyrite is commonly seen, particularly in the dark Levanna Shale. Large septarian concretions are seen in several layers within the Levanna Shale.

A4: SUBMARINE DISCONTINUITIES, ETC., IN THE UPPER HAMILTON GROUP
Gordon C. Baird
Field Museum of Natural History
Chicago, Illinois 60605
Carlton E. Brett
Rochester, New York 14627
As defined by Jenkyns (1971) condensed sedimentary sequences are differentially thin deposits recording minimum rates of net sediment accumulation. Such sequences are shown through correlation to be greatly condensed equivalents of thicker deposits; these latter typically display convergence of coeval zones or beds along their lateral periphery. It is possible for stratigraphic sequences to thin from hundreds or even thousands of feet to tens of feet or less while preserving or partly preserving the internal sequence of fossil zones or lithologic subunits. Stable depositional settings such as oceanic-rises and seamounts, regions of the open ocean floor, and broad epeiric shelf areas are commonly characterized by condensed sedimentary sequences. Selective winnowing of fines by currents and bioturbation effects, periods of nondeposition, inorganic degradation and biocorrosion of carbonates, exhumation and reburial of concretions and fossils, and juxtaposition or commingling of fossil zones are all variably characteristic of such condensed sedimentary sequences. Association of these sequences with local and regional discontinuities is also common as will be shown for part of the New York Middle Devonian section in this paper.
The upper Hamilton Group (Ludlowville and Moscow Formations) of the Cayuga Valley includes a thick sequence of marine mudstone characterized by widely spaced, thin limestone units and numerous mappable fossil zones. Several of these are associated with a widespread paraconformity and condensed sedimentary sequence at the base of the Moscow Formation; the differentially thin strata include the Portland Point and Kashong Members which are most compressed stratigraphically in the southeast part of the Cayuga Valley. These units thicken northwestward across the Cayuga and Seneca Valleys, 9.5 feet of strata (Portland Point and Kashong Members) at the Portland Point type section expanding to 100-110 feet in the Canandaigua Valley. The Tichenor-Portland Point Members disconformably overlie the King Ferry Shale in the Cayuga Valley, although evidence of erosion is lacking in most outcrops.

A4: SUBMARINE DISCONTINUITIES, ETC., IN THE UPPER HAMILTON

Cross mouth of Taughannock Creek
Cross mouth of Taughannock Creek at Taughannock State Park. To the left (upstream) from the road bridge a low waterfall is visible; this section includes the Tully Formation (limestone) overlying the uppermost Hamilton Group (Windom Member). Farther upstream is a splendid gorge-waterfall section exposing sediments of the lower Genesee Group (Upper Devonian: Frasnian Stage).

Cross Sheldrake Creek.

Cross Barnum Creek

Cross Bloomer Creek

STOP 1. Big Hollow Creek Section
(1 hour): At this stop we will examine both the Barnum and Bloomer Creek beds; these can be seen in the creek bed below the small farm north of the creek. The Barnum Creek bed is thin, but characterized by abundant flattish to ovoid hiatus concretions which are encrusted by Cladochonus and small bryozoans. The Bloomer Creek bed occurs about 150 feet upstream from the lower discontinuity and 12 feet higher in the section. This 8-inch-thick mudstone bed has numerous small corals (Pleurodictium, Stereolasma) which are commonly attached to phosphatic nodules and hiatus concretions. Above this unit is 25-30 feet of dark-gray and black shale. In a borrow pit upstream from the road crossing, the black shale grades upward to calcareous mudstone marking the base of Jaycox-equivalent King Ferry Member.

STOP 2. Bloomer Creek Section.
(1 hour and 20 minutes): We will walk north for 1500 feet crossing the main branch of Bloomer Creek to a more accessible section on its northern tributary. At this section we will observe the Mack and Bloomer Creek beds below the small waterfalls and study basal Moscow beds both at and slightly above the falls. This is one of the northernmost sections at which the Mack Creek bed can be observed. The Bloomer Creek bed occurs 8 feet above this unit; it is rich in brachiopod and molluscan debris and hiatus concretions are common; these display abundant epizoans.
The Tichenor Limestone Member occurs in the recess under the falls; it yields abundant pelmatozoan material including articulated crinoids. The Menteth and overlying Kashong Members occur upstream from the falls. Fossils are plentiful in the Kashong sequence, and they can be easily extracted from the Rhipidomella-Centronella Bed. The phosphatic pebble bed of the upper Kashong is inconspicuous, but it yields phosphatic pebbles and occasional phosphatic brachiopod and trilobite steinkerns. Return to vehicle and proceed back to main road.

STOP 3. Barnum Creek, Upper Ludlowville Section.
(2 hours, lunch first before examining the rocks): We will proceed around the waterfall, which is capped by the Menteth Member, and reach the creek by a safer downstream route. Wading up the creek, we will examine, in order, the Barnum Creek bed, Mack Creek bed, and Bloomer Creek bed. This is a classic complete profile shown schematically in Figure 2. Both the Barnum and Bloomer Creek beds yield a rich, shelly biota and numerous hiatus concretions. The disontinuities overlie intervals of mudstone bearing numerous in situ concretions which are the erosional source of hiatus concretions. Of particular interest is the occurrence of reworked, prefossilized conulariids in the Barnum Creek bed. Moreover, large differentially bored hiatus concretions occur in the Bloomer Creek bed; these show intense Trypanites borings on their upper surface and no boring underneath (Figure 6A). The nodules have different epizoan assemblages on their upper and lower surfaces, indicating development of microhabitats along their exterior.

STOP 4. Sheldrake Creek, Lower Moscow Condensed Stratigraphic Section.
(45 minutes): The Tichenor-basal Windom interval is represented by only 17-18 feet of section. The Deep Run Member is only 4.5 feet thick as opposed to 10 feet at Stop 2. The Menteth Limestone is thin and irregular in this section, and the Rhipidomella-Centronella bed of the Kashong Member is juxtaposed on it. The Tichenor Member is represented by a massive calcarenitic ledge with a sharp basal contact with the Ludlowville. Medial King Ferry beds will not be examined here, but the Mack Creek bed and the Bloomer Creek bed are both visible in the creek bank below the falls.

Portland Point quarry on left.
The Tully Formation (limestone) is quarried here, and the uppermost beds of the Moscow Formation (Hindom Shale) are exposed. For description of this locality see Grasso (1970) N.Y.S.G.A. field trip D and H, Stop 9. An excellent Tully-Windom exposure is developed to the right of the road in Minnegar Brook.

Salt mine to right.
The Morton Salt Company is mining salt from the Salina Group (Upper Silurian).

STOP 5a. Portland Point Type Section
(25 minutes): (see Figure 4). It occurs in a railroad cut along Cayuga Lake shore 300 feet south of entrance to Gulf Creek. There is noticeable southward dip to the strata so that 10-15 feet of uppermost King Ferry is visible below the Portland Point; the Portland Point-Kashong interval descends to railroad level over a 100-150 foot distance.
Originally, the Portland Point was described as including 9.0-9.5 feet of calcareous strata with a prominent calcarenite bed at the base and shell-rich limestone at the top (Cooper, 1929, 1930). The Portland Point is now redefined to include only the calcarenitic (Tichenor-equivalent) bed and overlying 2-foot muddy, Deep Run-Menteth equivalent limestone (Baird, 1979). 5.5 feet of succeeding beds are assigned to the Kashong Member. A prominent calcareous siltstone bed believed to be equivalent to the phosphatic pebble bed to the west occurs 8.5-9 feet above the base of the Moscow Formation; this may have been the top marker bed of Cooper's Portland Point section.
This bed occurs about one foot below a calcareous siltstone bed marking the base of the Windom. Above the base of the Windom are numerous Windom brachiopods including Athyris spiriferoides, Ambocoelia umbonata, and chonetids.

STOP 5b. Shurger Falls.
(20 minutes): We now walk back north to the mouth of Gulf Creek. Proceeding east (upstream) for 100-150 feet we come to Shurger Falls. The Portland Point is now at much higher elevation, capping the 40-50 foot waterfall. We will not climb the falls but will collect fossils from loose blocks which have fallen down.

A5: PALEOCOMMUNITIES OF THE ONONDAGA LIMESTONE (MIDDLE DEVONIAN) IN CENTRAL NEW YORK STATE
Richard H. Lindemann
Saratoga Springs, New York
Howard R. Feldman
American Museum of Natural History
New York, New York
The Onondaga Formation of New York State is a 21-50+ m unit of Middle Devonian marine limestones. The formation's outcrop belt runs east-west from Buffalo to the Helderbergs and southward from the latter to Port Jervis, a distance in excess of 550 km. Over much of this area the limestone strata have been eroded into extensive escarpments and flats.
Onondaga stratigraphy and paleogeography have received a great deal of attention during the past three decades. Formational lithofacies have been identified and interpreted. The lithofacies and paleocommunities of at least ten Onondaga bioherms have been investigated. However, until recently non-reef paleocommunities have been neglected. Feldman (1978, 1980) and Lindemann (1980) filled this gap through separate studies of Onondaga paleosynecology using similar yet divergent approaches. It is the purpose of this trip to familiarize participants with Onondaga stratigraphy and with the results of these recent paleoecologic investigations. To these ends, this article describes the formation and its faunas. In the field, we will consider the formation's paleoenvironmental setting and the degree to which temporal changes in environmental conditions influenced and are revealed by vertical successions of Onondaga paleocommunities.

A5: PALEOCOMMUNITIES OF THE ONONDAGA LIMESTONE (MIDDLE DEVONIAN) IN CENTRAL NEW YORK STATE

STOP 1. Indian Reservation Quarry
This is the Indian Reservation quarry described in connection with Feldman's Leptaena-Megakozlowskiella community.

STOP 2. Type section of the Edgecliff Member
This is the type section of the Edgecliff Member which is named for Edgecliff Park, located just to the west. The member's full thickness of 2.3 m is exposed in the upper areas of the main quarry. Its erosional base is marked by the presence of phosphate nodules. In the southern quarry wall, 3 m of the Nedrow Member are exposed. The top of the Nedrow has been removed by erosion.

STOP 3. A nearly complete section of the Onondaga
Turn left into the broad flat quarried area adjacent to Route 91 and park. The Onondaga is exposed in the upper quarry. Walk up into it by way of the unpaved road which comes down to Route 91 just south of where you've parked.
A nearly complete section of the Onondaga is exposed in this quarry. Only the top of the Seneca is gone. Thicknesses of the members are given below. An excellent exposure of the "Springvale" can be found to the west of the large storage building seen from Route 91. Here the "Springvale" contains a sparse brachiopod-bryozoan fauna and phosphate nodules. The main quarry floor is in the Edgecliff Member which is best seen along the south wall; it is at your right as you enter. Most of the quarry wall consists of the Nedrow and Moorehouse Members. This is the type locality of the latter. Fracturing and jointing of the rock have made hand and foot holds insecure. Please avoid falling or dropping rocks (or yourself) on other trip participants. The Seneca Member can be closely observed above and to the east of the main quarry. You can get to it by walking around the quarry to the north.
Seneca Member | 1.5 m
Moorehouse Member | 7.0 m
Nedrow Member | 4.4 m
Edgecliff Member | 5.2 m
"Springvale" | 1.5 m

STOP 4. Reef in Edgecliff Member
East of Taylor Road in the clump of trees across from the first house on the left is exposed a small section of a reef in the Edgecliff Member. While exposure does not permit a three-dimensional study of the reef, the fauna which includes Cylindrophyllum, Acinophyllum, Emmonsia, and Favosites indicates that what we are seeing is part of the core facies.

STOP 5. Full Edgecliff and some Nedrow
Going up hill and out of town there will be what appears to be a wooded and scrubby area on the left (north) side of the road. This is sharply broken by the school athletic field. Turn left into the western corner of the field and park near the storage shed. Frog Pond quarry is the scrubby area west of the athletic field. You can get into the quarry by way of any of the foot paths which lead in that direction.
The full 5.8 m of the Edgecliff Member are exposed here as is the lower 1 m of the Nedrow. The base of the Edgecliff is exposed on the middle of the quarry face which overlooks the frog pond in the southwest corner of the quarry. Rock weathering and extensive exposure of bedding surfaces make sampling and fossil collection here excellent.

STOP 6. Seneca Member
Proceed uphill until you see black shale to the right and Oneida Creek to the left. Look for and park in the wide road shoulder to your left as the road leans right. Watch out for eastbound traffic!
While virtually all of the Onondaga can be pieced together in the creek bed downstream from here, we will observe only the Seneca Member, 3.7 m of which are present in the stream. If water levels and recent sediment transport have been kind, we will be able to see a rare exposure of the contact between the Onondaga and the Union Springs Shale. For those who are interested, the full thickness of the Cherry Valley Limestone, about 1 m, is exposed on the north side of the road. There is no need to scramble up the shale for it, just trace the bed along until you meet it near road level.

A8: GLACIAL GEOLOGY OF THE CHENANGO RIVER VALLEY BETWEEN BINGHAMTON AND NORWICH, NEW YORK *
Donald H. Cadwell
New York State Geological Survey
Albany, New York, 12230
REGIONAL SETTING
The field trip area (Fig. 1) is located in the southern part of the Chenango River valley, a tributary to the Susquehanna River drainage system. The region is included in parts of the Binghamton West, Castle Creek, Greene, Chenango Forks, Brisben, Tyner, Oxford, Norwich, and Holmesville 7.5 minute U.S.G.S. topographic quadrangles. The area has a total relief of 341 m (840 to 1980 ft). The bedrock is predominantly Devonian shale, siltstone,and sandstone (Fisher et al., 1970).
GLACIAL GEOLOGIC SETTING
Brigham (1897) recognized the extent of the glacial sediments within the Chenango River valley between Binghamton and the Mohawk Valley. Tarr (1905) described the characteristics of the glacial deposits near the Finger Lakes. Fairchild (1932) named the thick drift units in the Finger Lakes region the Valley Heads moraine. He delineated other areas of drift deposits: the Olean at the terminal moraine in Pennsylvania and the Susquehanna Valley kames. MacClintock and Apfel (1944) used the term "Binghamton moraine" to describe the Susquehanna Valley kames of Fairchild, indicating that the drift was deposited during a separate advance. They suggested that the Olean was the oldest Wisconsin, Binghamton - middle Wisconsin, and the Valley Heads - youngest Wisconsin. Peltier (1949) correlated terraces along the Susquehanna River in Pennsylvania with pre-Wisconsin, Olean, Binghamton, Valley Heads, and Mankato ice advances in New York. Denny (1956) questioned the presence of the Binghamton advance in the Elmira region. He theorized that (1) the Binghamton border may be north of the Valley Heads border and therefore concealed, (2) the Binghamton border is incorporated within the Valley Heads border, and (3) the character of the Binghamton materials is completely changed between the type locality (Binghamton) and Elmira. Connally (1960, 1964) on the basis of heavy-mineral analyses indicated that the Binghamton is related to the Valley Heads advance. Moss and Ritter (1962) suggested that the Binghamton was not a separate advance, but a phase of the Olean. Coates (1963) suggested that a single ice sheet deposited the drift with the Olean as the upland facies and the Binghamton as valley facies. Hollyday (1969) showed that the drift in the valleys in the vicinity of the field trip ranges between 15 and 76 m (50 and 250 ft) thick. I have presented the idea of a single Woodfordian ice sheet that deposited the Olean and Binghamton deposits, with a minimum age of 16,650 ± 1800 radiocarbon years B.P. for wood at the base of a bog (Cadwell, 1972a, 1972b, 1973a, 1973b, 1974, 1975, 1978). Incorporated in this idea is the concept of "valley ice tongue" retreat. An ice tongue may have extended several miles down valley beyond the upland ice-margin position. Krall (1977) described the Cassville-Cooperstown moraine as a late Wisconsin recessional moraine. Aber (1978) described the erratic-rich drift in the Appalachian Plateau of N.Y.
* Published by permission of Director, Science Service, New York State Museum, State Education Department, Journal Series No. 326.

A8: GLACIAL GEOLOGY OF THE CHENANGO RIVER VALLEY BETWEEN BINGHAMTON AND NORWICH, NEW YORK

View south across Binghamton.
Binghamton is built on outwash sands and gravels greater than 50 ft (15 m) thick.

Note kame terrace to right.

Outwash sand and gravel exposed in the kame terrace.

Route 7 rises onto kame terrace at Hillcrest.

Note gravel pits in sand-and-gravel outwash to the left of Route 369 as you proceed north.

Kame is on left.

STOP 1. Chenango Valley State Park
All of the glacial features preserved in this park were formed at the retreating Woodfordian ice margin. Massive amounts of sand and gravel was deposited around disintegrating blocks of ice (Refer to the topographic map of the state park and vicinity). These horizontally stratified sands and gravels are at least 200 feet (61 m) thick. An ice-channel filling is preserved between Lily and Chenango Lakes. The pebble lithologies are 10 percent limestone; 75 percent local siltstone, sandstone and shale; and 15 percent exotics (from outside the Chenango River drainage basin).

Note the sand pit to the left.
These sands were deposited in relatively quiet water adjacent to stagnating ice in the Page Brook valley. Meltwater was flowing from the north.

Meltwater channel.
The sand and gravel here is at least 175 ft (53 m)thick.

Note large kettles in outwash gravels.

A radiocarbon age date of 16,650 yBP
A radiocarbon age date of 16,650 ± 1800 yBP was obtained from wood at the base of a kettle to the right, over the hill.

This kame terrace has at least 250 ft (76 m) of sand and gravel.

Large kame terrace
Enter Chenango County. This road is on a large kame terrace built when an ice tongue occupied the Chenango Valley. The sand and gravel is at least 196 ft (60 m) thick.

Gravel pit in outwash gravels
A gravel pit to the right (up the road) has outwash gravels. An ice tongue occupied the main valley as meltwater flowed from the ice margin to the east. The lithologies present are 4 percent limestone, 76 percent locals, and 20 percent exotics.

Proceed across the kame terrace.

View across meltwater channel and outwash gravels.
These sands and gravels are as much as 100 ft (30 m) thick.

STOP 2. Wheeler Creek Esker
This will be a brief stop to discuss the formation of the Wheeler Creek esker (Refer to the topographic map). A thin ice margin was located at this point. Meltwater flowed westward from this margin toward the main Chenango Valley. The kame terraces and the esker were deposited adjacent to and beneath the ice, respectively.

Esker on left.
The esker can be seen on the left as you descend from the kame terrace. Meltwater flow was to the south.

Road is located on the crest of the esker.

Note the massive hummocky topography
Note the massive hummocky topography (valley plug) on the east side of the valley. This sediment and ice served as a base-level control for deposition to the north. The significance of this will be discussed at STOP 3.

This road is on top of a large kame terrace.

STOP 3. Lynk Delta
The Lynk Construction Company removes sand and gravel from this large delta/lacustrine complex. Meltwater was flowing from the east along Lyon Brook and sedimentation occurred in a lake adjacent to an ice tongue. Note the planar-surfaced features to the north. The elevation of all these features was controlled by the valley plug noted at mileage 40.1. The lithologies present are: 20 percent limestone, 52 percent locals, and 28 percent exotics.

Note pit in kame delta to the right.

Cross alluvial fan.
The thickness of drift in the valley is at least 350 ft (107 m).

STOP 4. Wedge Or Pop-Up?
Walk up into the bedrock quarry. This pit is used by the state for maintenance of the roads. The face of the exposure is oriented N20E along one of the joint planes. The wedges are developed along N75W. One wedge is well developed. Two others are partially developed. The wedges persist for at least 3 ft. to the east.

STOP 5. Picture stop of kame terrace.
When this kame terrace was deposited an ice tongue occupied the main Chenango valley. Note kame delta on the west side of the valley.

STOP 6. Chenango County Sand Pit
The exposure in this pit illustrates lake sands, silts,and clays, with current-ripple laminations. Several years ago exposures in this pit had a section beneath the well-stratified lake sands. In this lower section are examples of strata with vertical bedding; horizontal bedding that abruptly ceased into an unstratified zone; and cross-bedded sands with inclinations of up to 85 degrees. The lithologies present include: 18 percent red sandstone, 25 percent limestone, 42 percent locals, and 15 percent exotics.
It is hypothesized that a supraglacial lake developed with deposition of the lower sands. The lake abruptly drained causing frozen blocks of sediment to be rotated. Sedimentation continued around the rotated blocks depositing the ripple-drift sediments.

Kame delta on right
Kame delta on right, with foreset beds dipping to the South.

Note exposure in kame terrace on right.

Good exposure in kame delta.

STOP 7. Emerson Pit
This kame delta illustrates the variety of sediments and orientations in a delta deposited adjacent to an ice tongue. Refer to the topographic map for STOP 3.

Note ice contact kame delta to right.
Stop if you have time.

View to the left (east) of valley plug
View to the left (east) of valley plug that controlled the elevation of the deltas examined at STOPS 3 and 7.

View to left (east) to outwash units associated with Wheeler esker (STOP 2).

View east to Chenango Valley State Park area.

STOP 8. Till
The drift in this valley includes Olean-type till, Binghamton-type stratified units, and thick lacustrine clays. These units are interspersed between bedrock outcrops. Rotational slump blocks develop by a process of piping in the silt and clay beds.

Good view to the south of Chenango River valley.

A9: HYDROLOGY IN RELATION TO GLACIAL GEOLOGY ALONG THE SUSQUEHANNA RIVER VALLEY, BINGHAMTON TO OWEGO, NEW YORK
Allan D. Randall
Over the past 20 years, several regional and localized studies have increased our knowledge of aquifers in the Susquehanna River basin of New York. This article extracts and summarizes some results of these studies that pertain to sites visited on this field trip along the Susquehanna valley from Binghamton downstream to Owego.
DISTRIBUTION OF AQUIFERS WITHIN THE GLACIAL DRIFT
About 85 percent of the Susquehanna River basin of New York is an upland in which shale, siltstone, and fine sandstone of Devonian age is dissected by narrow valleys and mantled by till. Stratified drift is confined largely to broad valleys, 1,000 to 8,000 feet wide, which occupy the remaining 15 percent of the basin.
During the waning stages of glaciation, tongues of ice extended southward along the broad valleys beyond the main ice sheet. Lakes formed near the ends of the shrinking ice tongues, temporarily filling any space vacated by melting of the ice that lay below the level of stratified drift previously deposited downstream. Many of these lakes were extensive, particularly in the deeper valleys, and trapped much clay, silt, and very fine sand. Elsewhere, particularly in relatively shallow valleys such as the Susquehanna River valley from Binghamton to Owego, smaller lakes and stream channels formed atop and against ice tongues that became too thin to flow. As each small lake filled with sediment, others formed nearby, and water velocities were often great enough to keep fine-grained sediment in suspension. The resulting stratified drift is heterogeneous but predominantly coarse grained, like the idealized sketch in Figure 1 and the actual cross sections in Figures 2 and 3.
Only the coarser sands and gravels within the stratified drift yield enough water to be considered aquifers.

A9: HYDROLOGY IN RELATION TO GLACIAL GEOLOGY ALONG THE SUSQUEHANNA RIVER VALLEY, BINGHAMTON TO OWEGO, NEW YORK

Note level terrace surface on right.

HESITATION STOP. Pit on left
Pit on left, in the highest (oldest) stratified drift in this part of the valley: cobble-boulder gravel to coarse sand variably silty (piles of coarse gravel rejected by operator are visible); pebbles are relatively drab (few limestones); topography is irregular, maximum altitude 880 feet; wet areas on pit floor suggest till at shallow depth. Barn on right marked "Tioga Manor"; trip will return past this barn.

Route 17C is on nearly level surface of valley train.

Pit owned by Concrete Materials, Inc.
Entrance (on left) to pit owned by Concrete Materials, Inc.

Pit owned by C & C Ready Mix Corp.
Entrance (on left) to pit owned by C & C Ready Mix Corp.

STOP 1. Kame Delta, Bright Gravel.
Stop 1 will be in whichever of these two pits offers the better exposures on the date of the trip. Topset and foreset beds of bright gravel have been observed beneath the valley-train surface; lower terraces are capped by bright fluvial gravel overlying fine-grained lake-bottom sediments.

STOP 2. Kames And Ice-Channel Filling, Drab Gravel.
Turn right at second driveway; proceed to gate at entrance to pasture and gravel pit owned by Kenneth Pipher. Be sure to close gate after entering.
Several pits in the kamic features in this locality revealed drab gravel and sand with very few limestone or other exotic rock types; west-dipping foresets have been observed. Maximum altitude is 860 feet, well above the bright valley-train surface to the east.

STOP 3. Ground-Water Recharge From Thorn Hollow Creek.
In 1967-68, streamflow measurements on 15 dates showed a loss of about 0.02 ft3/s (10 gal/min) per 100 feet of channel upstream from Glen Mary Drive and 0.16 ft3/s per 100 feet downstream. During most of the year, this stream goes dry somewhere on its alluvial fan.

Note road bordered and arched over by large maples.

Tioga Manor barn on right.
Behind barn is a hummocky surface 820-830 feet in altitude; a small pit revealed 1.5 feet of highly calcareous, bright, fine-pebble gravel with abundant limestone atop several feet of drab gravel.

HESITATION STOP. View to right of oval hill
View to right of oval hill in midvalley, composed of (or perhaps heavily mantled with) till. Terraces at about 830 feet altitude between the road and the hill, now largely excavated, were capped by bright fine-pebble gravel and coarse sand.

HESITATION STOP. Tracy Creek
The reach of Tracy Creek beneath the bridge visible to the right was dry on all eight occasions when visited by the U.S Geological Survey in the summers of 1962-65 as part of a study of low streamflow in the Susquehanna River basin. Like most tributary streams, Tracy Creek suffers severe seepage loss when crossing the stratified drift in the Susquehanna River Valley. Upstream 2,000 feet, where the creek has cut a gorge through till and bedrock, a small flow continued throughout the 1962-65 drought.

Cross Choconut Creek

Vestal municipal well is in well house on right.

STOP 4. Vestal Water District 1 Well Field.
Three municipal wells tap sand and gravel between 70 and 150 feet in depth. Induced river infiltration is potentially an important source of recharge; temperature profiles in April 1981 indicate river water infiltrated past well 1-3 at a time when only well 1-2 was in use. The sand and gravel seems to be relatively drab, perhaps totally drab near the base.

STOP 5. Vestal Water District 4 Well Field.
To the west is municipal well 4-2, water from which was found to contain organic solvents in 1980 (see text). To the north are two more municipal wells. To the south are numerous oil tank farms. To the east, the land was once level with Prentice Road, but has been excavated for gravel; the owner plans to mine gravel below the water table by dragline both east and west of the road. The pit to the east was once considered as a site for a municipal landfill

Flood-control reservoir
Flood-control reservoir is on right, on little Choconut Creek.

STOP 6. View Of Housing Cluster.
All homes in this area have public sewers and on-lot wells tapping bedrock. In 1981, water levels were as deep as 100 to 130 feet seasonally in some wells on Rhodes Road, and yields of a few wells were not as large as desired by occupants. Further building has been proposed downslope.

A10: GEOMORPHOLOGY OF SOUTH-CENTRAL NEW YORK
Donald R. Coates
Dept. of Geological Sciences
SUNY-Binghamton
The purpose of this trip is to examine geomorphology in the region to the east and south of Binghamton. The evolution of the Chemung, Delaware, Susquehanna, and Tioughnioga Rivers will be discussed. A variety of erosional features will be seen and much emphasis will be placed on glacial deposits and the landforms they create. The starting point of the trip will be the upper part of the SUNY Binghamton campus.

A10: GEOMORPHOLOGY OF SOUTH-CENTRAL NEW YORK

STOP 1. Campus Overview.
This site is the southernmost of three east-trending ridges which comprise a ribbed moraine sequence. The SUNY campus is situated on two of the ridges. Furthermore, the campus is nested in a reentrant in which the bedrock hillslopes have a scalloped form. Roundtop Hill, an umlaufberg, can be seen to the north. The drainage divide to the south contains a col, or saddle, which was the position for override by the glacier. The moraine is composed of bright till (Binghamton-type) with a fabric transverse to the ridge (or parallel with ice transport). Bedrock is more than 120 ft below land surface. All glacial deposits on this trip are Late Wisconsinan. Embark. Travel east on ribbed moraine with SUNY nature preserve and wetlands to south.

STOP 2. Stair Park.
Walk into park going south along Fuller Hollow Creek. Stream flows on bedrock, yet the floodplain appears to be in alluvial materials. Why has stream chosen a more difficult channel to occupy? Walk to 30-ft exposure of bright till (Binghamton lithology). What is the fabric of the till? Within Fuller Hollow there are good examples of fabric wherein some show extending flow and other compressing flow characteristics of the glacier. Such bright drift shows the history of materials. The ice moved south over the valley-fill sediments of the Susquehanna River, incorporating them into the basal load and then depositing them south of the river along thrust planes as the ice was forced to move up and over the hillsides. South from this stop the drift changes composition, passes into a transitional facies and finally becomes true "drab" till (Olean lithology) higher up on the hillsides.

In distance note the Roundtop Hill umlaufberg.
The highway uses the meltwater channel that separates the hill from the former upland parent spur to the south.

The river flows west on valley-fill sediments.
The river flows west on valley-fill sediments about 200 ft thick comprised largely of glacio-fluvial and glacio-lacustrine materials. Near Route 17 wood at about an 8-ft depth in alluvial materials was dated at 1690 ± 100 ybp.

STOP 3. Drab till (Olean lithology)
This 25-ft exposure east of Oakdale Mall consists of drab till (Olean lithology). This is typical of lodgment till plastered on the south sides of hills that produce asymmetry of hills, or the "till-shadow effect". What type of fabric would you anticipate from such a depositional environment?

Upper Rhinestreet Formation
Bedrock exposure of Upper Devonian Rhinestreet Formation consists of marine shale with some siltstone.

Chenango River.
Note flood walls, and revetment-type levees (armored with riprap) built by U.S. Army Corps of Engineers. Near this

Hillside quarrying of Rhinestreet Formation.
Binghamton brickyard and hillside quarrying of Rhinestreet Formation. The highway is adjacent to old Chenango Canal that connected Binghamton with the Erie Canal. The trend of the canal along here is called the "tow path" by residents.

Kame-terrace valley-train sediments
Exposure of kame-terrace valley-train sediments that comprise Hillcrest. Note highly cemented character of materials.

Cross Chenango River
Here valley fill is less than 100 ft thick. Note the umlaufberg, which is double crested. This part of the valley is more youthful because river was diverted from its earlier course on north side of umlaufberg.

Old valley of Chenango River
Note the route has been along west side of umlaufberg into the old valley of the Chenango River. This is now a "dry valley" filled with a congestion of glacial deposits and sand and gravel pits.

STOP 4. Rose Gravel Pit (now owned by Barett Paving, Inc.).
Travel into east part of pit, 1.2 mi. These materials occur in a very complex sedimentary environment. This can be considered a pitted outwash plain (sandur), that also includes valley train, kame, kame terraces, and extensive pro-gradational deltaic sequences. Although the deposits were formed during a single glacial stade and are comprised by materials of the same general provenance, there is great heterogeneity in the sediments from outcrop to outcrop. Thus the pit contains both pure outwash-type sediment as well as ice-contact deposits. There is a full range of textures from clay to silt, sand, gravel, cobbles, and boulders. Bodies of till also occur within some sequences. The extent, both laterally and vertically, of the cemented units pose serious problems for the miner. Geologically the problem is to determine the origin and time of cementation. For example, did it form in the vadose or groundwater zone? Did it form soon after deposition, or later in the Holocene? Aber (1979) has attempted to answer some of these points. Although much of the material is bright, there are also occurrences of drab drift. Why?

Highway ascends a wind gap.
This is one of three high-level notches along a north-trending ridge formed as overflow channels when ice occupied the Chenango Valley and meltwater streams discovered high outlets.

STOP 5. Chenango Forks.
This is junction of the Chenango River flowing southwest and the Tioughnioga River flowing southeast. The exposure typifies the many different sedimentary features at junctions of two different ice lobes, with contrasting histories and meltwater regimes. This is a kame environment with deposits that range through glaciofluvial, glaciolacustrine, and unsorted materials. What is the origin of the large bouldery unit? Possibilities include flowtill, mudflow - debris flow, ablation till, etc. Are there others?

STOP 6. Landslide.
This landslide consists of a series of slumps that cover a 7-acre area. It was caused when the road was cut into the lower hill slope. The increased slope and removal of material destabilized the materials. The hydraulic head increased and drainage from a road above the slide funneled water onto the mass. The hillside materials are composed of sediments susceptible to piping which enhance lubrication and movement of materials in the mass. Some pipes have been measured to be about 2 ft in diameter and extend many feet into the hill. The south side of the area is composed of drab till. Most of the slide occurs in glaciolacustrine silt and fine sand with clay more than 60 ft thick. Glaciofluvial beds occur immediately north of the slide area. What was the environmental setting when the deposits formed?

Bedrock.

Drab (Olean lithology) till.
These sequences are typical of the Tioughnioga River, a multi-cycle sluiceway or beaded river. The river is anomalous because it flows southeast across the structural grain of the region. The valley alternates between narrow walls which are younger parts of the system, and wider valleys which represent positions where the river discovered its previous valley.

Many kettles comprise this pitted valley train.
The road passes between many kettles which comprise this pitted valley train. Cadwell (1972) dated peaty materials in a kettle as 16,650 ± 1,800 ybp.

Old gravel pits on both sides of road.
Sedimentation is outwash type.

STOP 7. Chenango Valley State Park.
Separating Lily Lake to the north and Chenango Lake to the south is a crevasse filling. The lakes occupy kettle holes. The park contains tens of kettles of various sizes. These were stranded "land icebergs" that were overwhelmed by meltwater deposits when active ice was to the north.

STOP 8. Hale Gravel Pit.
Good example of outwash deposits. Bedding shows characteristics of the shifting meltwater channels that provided avenues for deposition of the materials. Although these are outwash deposits, they contain deleterious ingredients and so fail to pass state (magnesium sulfate soundness test) requirements for use as highway concrete (>18 percent loss on 10-cycle test). Why? What is the lithology of the sediment?

Bedrock - more youthful part of system
The Chenango River enters a more youthful part of its system, with the umlaufberg separating it from the former thalweg. Bedrock in or near a stream invariably means the channel is not located at the major thalweg.

Belden Hill. One of highest elevations in this area.
Drainage divide between the Susquehanna and Chenango Rivers.

On east side of Susquehanna is "The Plains"
On east side of Susquehanna is "The Plains" one of largest terraces in the region. Along the road there are many stagnant ice features.

Start of 0.6-mi - long esker
Start of 0.6-mi - long esker that parallels the highway on east side.

The road arcs around the Windsor umlaufberg.

STOP 9. Town Of Windsor Gravel Pit.
Turn right onto dirt road and proceed to working area. This is a beautiful "textbook" example of a kame, a hill composed of ice contact deposits. Meltwater erosion was responsible for dissecting the umlaufberg from the upland connection to the east. The deposits fall within the range of drab lithology and contain glaciofluvial, glaciolacustrine, and poorly to unstratified drift. What is the origin of the latter?

Kame-and-kettle topography, character of the umlaufberg
Note kame-and-kettle topography and the character of the umlaufberg, which can be considered "youthful" because of the lack of tributaries on it and the adjacent highlands.

Damascus.
Continue east on old "17" which now rises on a steep grade up Tuscarora Mountain.

Sky Lake, one of three natural lakes in Fly Creek.
This is drainage divide between the Delaware and Susquehanna Rivers. We are now in the Catskill Mountains, both geologically and geographically. The bedrock now consists mostly of terrigenous sandstone. Relief is 1500 ft and more, and the Delaware system drains the west and southwest part of the mountains.
2011: Sky Lake is 1.2 miles from here, over the hill to the NE. The road to Sky Lake is a few hundred meters back along the highway.

Deer Lake, second in the lake chain in Fly Creek.

STOP 10. Fly Pond. Picture stop.
A till barrier impounds this and the others have similar dams. What is the origin of these barriers? Depth to rock is reported to be 160 ft in the valley. There are also two smaller till mounds in Fly Creek.

STOP 11. Kame Delta.
At 1450 ft elevation this is an unusually high level deltaic deposit. However, it forms part of the large picture with a major lake that occupied the Gulf Summit area.

Major topographic low.
Note this area appears to be a major topographic low. Within it are numerous kames and kettles.

Spillway for drainage of the proglacial lake
Travel down road and observe character of the drainage divide at Gulf Summit. Return to railroad and view the deep bedrock notch. This was the spillway for drainage of the proglacial lake that occupied this topographic low. Although Wisconsinan-age meltwaters helped to incise the lowermost 70 ft, the higher features may have been initiated during earlier glacial stages.

STOP 12. View Of Spillway And Overflow Channel.
This is headwater area of Cascade Creek, a Susquehanna River tributary. The Catskill sandstone shows vestiges of stream erosion. North of the road the hill slopes contain varying degrees of blockfields, a reminder of periglacial climatic conditions.

Triple cities of Lanesboro, Susquehanna, and Oakland.
This is the Great Bend area where Susquehanna River arcs from a south flow, to an east flow, then a north flow. The unusual stone masonry bridge was built in 1848 by a Scotsman, Kirkwood, after several earlier contractors had gone broke attempting to build a span across the valley.

STOP 13. Oakland Esker,
Oakland Esker, largest in the region, with total length about 4 mi. Here it is on north side of the river but it can be followed northward where the river has incised it and the esker continues again on east side of river. The esker is not a simple ridge, but is double in several parts, such as near the outlet on the west side of Oakland. Side slopes are steep and esker exceeds a height of 100 ft. At the top there are depressions and undulating topography. Exposures here and at other outcrops show bedding ranging from horizontal to some units whose dips exceed 45°. Till and flow till are interpreted to be part of some sequences. The sparse number of exotics indicate the drift is drab type. Was this a supra-glacial (open to the sky) or subglacial esker?

Western limit of esker.

Penny Hill on north side of road.
There is a "rock city" at top of the hill, another indication of periglacial conditions.

Hanging delta on east side of highway.
This is the valley of the north-flowing Salt Lick Creek. The straightness of the valley, truncation of spurs, and anomalous southern extension indicate valley sculpture by ice and meltwater erosion.

Enter the New Milford sluiceway.

The most recent meltwater erosion starts here.

STOP 14. Picture Stop For The New Milford Sluiceway.
This is the south-trending Martin Creek valley, with bedrock walls of Catskill cross-bedded sandstone. This is a "youthful" type or first-cycle sluiceway because of the imperfect development of tributaries and absence of till. The feature was developed when meltwaters from a proglacial lake to the north drained south through spillways formed during earlier glacial times. The Great Bend region had a long and involved history throughout Quaternary times. The unusual geometry of the Susquehanna River implies it is an ice-marginal valley, such as parts of the Missouri and Ohio Rivers.

STOP 15. Hanging Delta.
This delta owes its development to events in Little Egypt Creek, the north-flowing stream on the east side of Maunatome Mtn. Along this north-south ridge there are a series of high level notches occupied by ice and meltwaters during different glacial and proglacial times. Drainage in Little Egypt was blocked by ice to the north causing the eventual overflow of the proglacial lake into Salt Lick Valley, where another lake received the sediments. Typical deltaic structures occur: topsets, foresets, and a general lobate pattern of strata that dip away from the central core. The materials are drab and currently used by the Pennsylvania Highway Department. The deposits are more than 150 ft thick. How did the massive sandstone block become emplaced within the sediments?

STOP 16. Doubleday Glen.
The Rhinestreet Formation forms bedrock of the area. Note the fabric of unconsolidated materials on top of rock. This is colluvium. Although composed of till it is not in place, having moved downslope by solifluction processes which produced the preferred orientation of the slabby clasts. Walk into the glen. Evolution of this feature is somewhat similar to the famous Finger Lake glens. They developed during postglacial time when a high-level consequent stream starts its new trajectory. Because till covered the preglacial valley and diverted streams to the south, many of the newly developing consequent streams were forced to carve new bedrock chasms. Thus when streams miss their former valleys, they incise rock and form narrow, steep-walled valleys. Where former valleys were encountered, the walls are gentler, not in rock, and wider.

B6: BIOCLASTIC CARBONATE UNITS IN THE CATSKILL CLASTIC WEDGE
Donald L. Woodrow
Hobart and William Smith Colleges
Geneva, New York
Paul Enos, Richard J. Bottjer and Charles Minero
State University of New York at Binghamton
Binghamton, New York
This trip we will visit two quarries in northern Pennsylvania (Fig. 1) which expose thick carbonate units nearly unique in the "Catskill delta". Our purpose is to examine these units and to discuss their origin, which in many respects remains enigmatic despite considerable study.
Each of us has contributed to this guidebook in a different manner.
All of us have examined both quarries in varying levels of detail. Woodrow and Bottjer measured sections in the Case quarry and considered the trace fossils and petrography there. Minero measured the Ashcraft quarry sections. Enos and Woodrow have supervised the work of several students in both areas.
STRATIGRAPHIC CONTEXT OF THE CARBONATE ROCKS
Rocks seen in the two quarries are part of the Catskill clastic wedge (Woodrow, 1968). Carbonate-rich rocks are unusual in this sequence which is typified by sandstones, siltstones, and shales. Both units were worked initially for agricultural lime, and quarries were later opened because the carbonates provide the best material for riprap available for many miles.

B6: BIOCLASTIC CARBONATE UNITS IN THE CATSKILL CLASTIC WEDGE

Esker on north (right) side of N.Y. 17.
Much of esker and associated kamic deposits have been removed for aggregate.

Small exposures of Chemung
Steep wooded hill with small exposures of Chemung (shallow marine) facies.

Road cut, Chemung facies.

Exposure of Chemung facies on right (W).

Road cut in Wiscoy Fm. (?)
Road cut in Wiscoy Fm. (?), Chemung facies, (shallow marine).

Road cut in lower Towanda Fm.
Road cut in lower Towanda Fm. Cattaraugus facies; red beds, some coquinite.

Road cut in Towanda Fm.
Road cut in Towanda Fm. with abundant flow rolls (pillow structures).

STOP 1. Louis Case Quarry, Burlington, Pa.
Enter Louis Case quarry on right (N) side of U.S. 6. Obtain permission from Louis Case in house at west edge of quarry.
Start in small face below main bench of quarry. Work upward toward east end of quarry.
The points of similarity between the two carbonate bodies (Table 2) are such that we conclude that both were formed in tide-influenced marine environments. However, contrasts between them are sufficient to make it clear that the local geography of the Catskill shoreline at the two sites must have been different. The abundance of brachiopods and the presence of crinoids and in situ bryozoa demonstrate that the environment of deposition of the coquinite was subtidal marine. Tidal effects are indicated by material from both marine sources (shells) and terrestrial sources (plant fragments, red muds), by the intimate intermixture of sandstone and shale (including flaser bedding), and by some examples of reversals in current direction. Most of the large-scale cross-strata record flow toward the west or northwest suggesting ebb-dominated deposition.
If the question of process is tentatively answered. we are left with the question posed by the mixture of materials in the coquinite. The source of the shell material was the local sea floor, despite the apparent ebb dominance, but the source of the red mud is less obvious. A source of highly oxygenated muds is required, perhaps from the higher, subaerial parts of a tidal flat or nearby alluvial plains. Plant debris could derive from the same sources. Shells in great quantity require a large community of epifauna either close to or as part of a tidal shore. The bryozoan clusters, at least, point to some production in situ.
The coquinites of the Case quarry have been interpreted as a part of a tidal delta (Woodrow) and as a subtidal zone of a tide-dominated fluvial delta (Bottjer). Strata above the coquinite indicate alternations of shallow marine and non-marine or supratidal environments. They contain mudcracks, in situ pedogenic carbonate nodules in red mudstones, and the enigmatic burrows or root cases; interlayered are beds containing marine fossils.
The local Upper Devonian shoreline was dominated by tidal processes, not by large streams and fluvial-dominated deltas. Material delivered to the shore appear to have been carried by small streams draining an alluvial plain or in channels of a tidal coast. Evidence of a large tidal range is lacking; a range of less than a couple of meters would probably account for the tidal features. Flow velocities were high enough in some areas, however, to move coarse material (shells and sand) as well as fines and to deposit them as migrating dunes and ripples. The localization of thick carbonate units may result from local amplifications in the tidal range or tidal velocity perhaps caused by indentations in the shoreline (bays).
In summary, both sequences appear to result from the concentration of shell debris, quartz, rock fragments, nodules, and wood by high-energy sedimentary processes in ebb-dominated tidal environments. Differences in lithology and geometry between the two units probably reflect local differences in the shoreline.

Kiln on left (N) side of road
Kiln on left (N) side of road where coquinite was exploited for agricultural lime and mortar. This is the type locality of the Luthers Mills Coquinite.

Large blocks of coquinite
Jct. township road. Large blocks of coquinite exposed in bed of Sugar Creek at sharp curve to west approximately 1/2 mi. north of U.S. 6. Long road cut in Towanda Fm. beginning at curve on township road.
2011: The township road is called Buttermilk Falls road, I believe. OHM

Overview of Susquehanna Valley to north

Overview up Susquehanna Valley to north.

Road cut in Towanda Fm.

Road cut in Wiscoy Fm. (?)

Potential lunch stop.
Rest area at Tioga Park race track (a monument to human folly).

Outcrops of Rhinestreet Fm.
Outcrops of Rhinestreet Fm., Chemung facies, to right in bed of Tracy Creek.

STOP 2. Ashcraft Quarry, Little Meadows, Pa.
Permission to visit quarry is obtained from Ashcraft Excavating Co. on Pennsylvania Ave., 2.5 mi south of N.Y. 434 in Apalachin, N. Y. Start in pit near east end of quarry. Work along main face to west end. Climb onto bench at west end.
The features of the limestone unit and of the strata surrounding it are explainable in terms of sedimentary process operating in shallow-marine environments where both tidal currents and waves were effective. There are few features of the limestone which suggest subaerial exposure, while the presence of brachiopods and crinoids and the development of a variety of sedimentary structures suggests deposition in shallow marine water. Reversals in current direction indicated by the paleocurrents, the textural maturity of the sand lenses within the limestone, and the lack of mud within the carbonate suggest a shallow-marine setting in which strong tidal currents winnowed out the fines and abraded the shell materials.
Shells, quartz sand, shale clasts, reworked nodules, plant fragments, and bones were all transported to this locality. The nodules and shale clasts must have been transported by strong currents from sources not too far distant, judging from the large clast size and relative lack of abrasion. The shells must have been transported from the nearby sea floor with extensive concentration and reworking to account for their numbers and abraded condition.
The internal plan of the carbonate mass seems to require three kinds of sedimentary processes: a) erosion and transport of sand, shells, nodules, etc. to the site; b) vertical accretion to form positive depositional relief; and, c) lateral accretion to produce the ultimate accumulation as either an isolated mound or a tabular body.
Thus, the carbonate mass appears to have been an accumulation built up above its surroundings by currents bringing to the site materials from the nearby sea floor or lagoon and from nearby terrestrial sources. Five hypotheses of accumulation have been suggested, no one of which is completely satisfactory or can be tested adequately with the available data. They are offered here as a basis for discussion.
Deposition as a subaqueous "shell mound" seaward of a beach/lagoon complex and/or a tidal flat was suggested by Krajewski and Cuffey (1976). Bowen (1978) postulated a "break-point bar" offshore from tidal flats. Both Krajewski and Cuffey (1976 and Bowen (1978) suggested significant contributions of skeletons produced in situ once initial relief above the sea floor was established. Another possibility is deposition on the subaqueous part of a land-tied accretion lobe or spit (Enos and Minero). Accumulation in the form of a tidal delta with both ebb and flood deposits represented has been suggested by John Bridge (pers. comm., 1981). Finally, some of the features in the unit are compatible with development as a small, mostly submerged, barrier bar as hypothesized by Woodrow.
In any event, nodules and other clastics were brought to the site of accumulation as the result of fluvial or shore-zone erosion and transport. A swamp seems the most likely source of ankerite nodules and abundant plant material. Shale clasts could have come from either the landward side or the seaward side of the carbonate accumulation. The source must have been one where mud normally accumulated and was periodically eroded. Wave and/or tidal scour of the nearby shelf provided the shells. Tides and waves reworked these particles into the limestone we see now.

B7: SOME ENVIRONMENTAL PROBLEMS OF THE BINGHAMTON AREA
Marie Morisawa and Burrell Montz
Department of Geological Sciences and Environmental Studies
State University of New York at Binghamton
Binghamton, New York 13901

B7: SOME ENVIRONMENTAL PROBLEMS OF THE BINGHAMTON AREA

STOP 1. Pierce Hill Cut.
This is a slope with active movement of material downslope. Originally a borrow pit. the slope has been cut back even more for the commercial development you see. Debris slides, slumps, rilling and rock fall are modes of downslope movement of the glacial materials. Both Howard's Florist and the Red Lobster have gone to considerable expense to stabilize the slope. One debris flow behind the Red Lobster reached the back door, covering several cars in the way. Subsequently. the wall and drainage pipes were installed.

STOP 2. Lower Fuller Hollow Creek.
Here the creek has been riprapped to prevent erosion of the bed and further down the banks are riprapped. The riprap has progressively deteriorated, large blocks have removed and side-walls have slumped.

STOP 3. Middle Fuller Hollow Creek.
Evidence of destructive erosion can be seen here. The foot bridge was washed out in the spring of 1981. Note widening of the channel. Excessive runoff from storm drains have caused much erosion here. Along the downstream reach many landowners are losing their back yards.

STOP 4. Upper Fuller Hollow Creek.
From this viewpoint. one can see the 300 home Stair development. The whole hillside was wooded until approximately 1974-75. Tributaries and storm runoff are piped underground directly to the creek, greatly augmenting flow during storms. Directly below is a meadow through which the main creek flows. This would have been an ideal spot for a detention pond to which runoff could have been piped.

STOP 5. Vestal Plaza Slope.
This cut has failed in many places since it was made. The north-facing slope has moved much more and did so more quickly than the south-facing slope. The cut is in glacial material. Much of the fine sediment has been removed by mud flows which cover the road whenever it rains. Buildings and parking lots on the surface above the slopes have contributed to mass movement.

STOP 6. Rockbottom Dam.
This dam is currently being rebuilt after years of deterioration on the older one. The dam is designed to retard the flow of water and to produce ponding so that the water intake for the City of Binghamton's water supply is below the surface even in dry years.

STOP 7. Susquehanna River.
The bend in the river at this point led to flooding of the area between the river and the gas station during the ice jams in February.
2011: This is the second Stop 6 on the road log. OHM

STOP 8. Conklin Park.
This park was flooded entirely during the February 1981 flooding. Water levels reached up to the park sign. Although there are some buildings in the park, they are for storage, primarily. This park is a good example of how flood plain areas should be developed.
2011: This is Stop 7 on the road log. OHM

Note the houses in this area
Note the houses in this area (which was also flooded in February). Each has a nice view of the river and gets flooded-almost annually. These are obvious examples of uneconomic floodplain development.

B11: DEPOSITIONAL ENVIRONMENT OF THE ONEONTA FORMATION (CATSKILL FACIES), NEAR UNADILLA, NEW YORK
John S. Bridge And Lorraine E. Dingman
Binghamton, New York 13901
A large roadside exposure on Interstate 88 near Unadilla (Fig. 1) offers a unique opportunity for detailed study of both vertical and lateral lithofacies variations in the Upper Devonian Catskill facies.
The rocks are assignable to the Oneonta Formation (Fletcher, 1963; Rickard, 1975), and the postulated early-middle Frasnian age (Polygnathus asymmetricus conodont zone) of this formation is supported independently by the miospore studies of J. B. Richardson (pers. comm.). This paper presents a detailed description and interpretation of the lithofacies, and a brief comparison with other published studies of Catskill-facies sedimentology. For convenience, the rocks were separated into two main facies associations which can usually be clearly distinguished in the field.

STOP 1. Oneonta Formation, Catskill Facies.

NEW YORK STATE GEOLOGICAL ASSOCIATION 54th ANNUAL MEETING
Amherst, New York
GUIDEBOOK FOR FIELD TRIPS IN WESTERN NEW YORK, NORTHERN PENNSYLVANIA AND ADJACENT, SOUTHERN ONTARIO
Edward J. Buehler and
Parker E. Calkin Editors
Held in Conjunction with 11th Annual Meeting Eastern Section American Association of Petroleum Geologists
Published by the New York State Geological Association. Guidebook available from the executive secretary: M.P. Wolf, Geology Department, Gittleson Hall, Hofstra University, Hempstead, New York 11550.

A1: UPPER MOSCOW-GENESEE STRATIGRAPHIC RELATIONSHIPS IN WESTERN NEW YORK: EVIDENCE FOR REGIONAL EROSIVE BEVELING IN THE LATE MIDDLE DEVONIAN
Gordon C. Baird
SUNY College at Fredonia
Fredonia, New York 14603
A widespread regressive episode, immediately preceding the late Middle Devonian Taghanic onlap, has long been recognized in eastern North America (Grabau, 1917; Cooper, 1930; Cooper and Williams, 1935; Heckel, 1973; Dennison and Head, 1975; Rickard, 1975). Regional erosive overstep of Hamilton beds by Tully and Genesee strata was documented in the Finger Lakes area (Cooper and Williams, 1935) and was recognized west of Canandaigua Lake (Cooper, 1930), but the nature of pre-Taghanic unconformity in western New York remained obscure due to supposed lack of stratigraphic controls in the upper Moscow (Windom) shales. Indeed certain workers (Stover, 1956; Fulreader, 1957) believed that upper Windom beds were relatively little affected by erosional truncation.
Contacts of the Middle Devonian Windom Shale Member, previously examined and discussed (Brett, 1974a; Brett and Baird, 1975), have received continued study by the present authors; results of new work on the Windom-Genesee paraconformity and adjacent strata in the Erie County region are discussed herein.
Detailed correlation and study of Windom Shale component zones has been undertaken. At least fourteen mappable Windom marker beds and intervals have been correlated across all, or part, of Erie County; these are summarized in the present text. Mapping of Windom units immediately underlying the Genesee Formation permits detailed inference as to the nature of this unconformable contact. These beds also provide insight into the processes of marine mud sedimentation during deposition of the Windom and its influence on fossil community distribution. Particularly notable is the discovery that the thickest Windom sections in the county are the least stratigraphically complete and the thinnest generally display the full complement of marker beds and zones.

A1: UPPER MOSCOW-GENESEE STRATIGRAPHIC RELATIONSHIPS IN WESTERN NEW YORK: EVIDENCE FOR REGIONAL EROSIVE BEVELING IN THE LATE MIDDLE DEVONIAN

Roadcuts in cherty limestone of Onondaga Limestone
Roadcuts in cherty limestone of the Clarence Member, Onondaga Limestone (Middle Devonian). This is the site of the Vogelsanger Quarry; prior to construction of the highway, this quarry exposed a well developed reef in the Edgecliff Member (now covered).

STOP 1. Bay View (Penn Dixie) Quarry.
(1 1/2 hours): This abandoned shale pit, previously described in detail (Brett, 1974b), provides an excellent reference section for the Windom Shale and its upper contact with the Genesee Formation. Here the Windom Member is approximately 13 m (42 ft) thick; 14 units described in the text can be recognized at this 1ocation. The disconformable basal contact with the Tichenor Limestone is excellently exposed in a low domal outcrop in the northeast corner of the shale pit.
The basal Ambocoelia umbonata beds Bay View Coral bed (type section) and Smoke Creek bed are accessible in this area. Barren shales of unit 4 occupy much of the flat floor in the center of the shale pit. Near the top of this interval is a narrow zone containing abundant fossils including highly compressed brachiopods (Pseudoatrypa, Mediospirifer, Mucrospirifer consobrinus) and rare pyritized sponges and blastoids; this unit is termed the Big Tree bed (unit 5). The A-E limestones (units 6-11) crop out as uniform, white-weathering bands which trend roughly east-west across the quarry. Soft shales above the highest limestone band (unit 12) yield abundant pyritized burrow fillings and fossil steinkerns including nuculid clams, gastropods and cephalopods. This interval of approximately 2 m (6 ft) thickness, termed the Penn-Dixie pyritic beds, is characterized by small specimens of the brachiopods Tropidoleptus carinatus and Ambocoelia cf. A. nana. The calcareous Amsdell bed unit 13; = "Praeumbona bed") caps a low bench near the southern end of the quarry. Beyond this the Penn-Dixie shale pit terminates in a low (2-3 m high) bank which exposes uppermost Windom beds (unit 13) and the contact with the overlying Genesee Formation. The upper beds of the Windom comprise soft, gray shales with concretionary beds near the top; the top of the Windom is marked by a concretionary layer of 20-30 cm (8-12 in) thick containing Ambocoelia? praeumbona, followed by a thin band of argillaceous limestone which has been partially torn up and incorporated in the overlying North Evans Member.
The North Evans Limestone of the basal Genesee Formation comprises 3-10 cm (1.5-4 in) of buff-weathering, dark-gray crinoidal, calcarenitic limestone, which contains very abundant conodonts of mixed zones (lower asymmetricus subzones). Angular intraclasts, up to 10 cm (4 in) across, derived from the upper Windom occur abundantly in the North Evans. Black shales (Geneseo and Penn Yan) are absent from the lower part of the Genesee Formation and the Genundewa Member, a thin Styliolina-rich limestone rests directly on the North Evans.
At Penn Dixie Quarry as at most localities in western Erie County, the Windom is thin, but stratigraphically quite complete. However, ironically, in these sections unlike those farther east, the upper contact exhibits evidence for erosional scouring. Presumably the scouring of the upper Windom beds and presence of pebble imbrication within the North Evans remanié sediments reflect a late episode of erosion, associated with the pre-Genundewa erosion surface. This event post dates the development of a south dipping truncation surface, prior to Tully deposition, which had left upper Windom beds relatively intact in southwestern Erie County sections.
2011: Now owned and operated by Hamburg Natural History Society, Inc. http://www.penndixie.org/welcome.html   OHM

STOP 2. Cazenovia Creek Section.
Park near location where power lines cross Northrup Road. At utility poles on east side of road turn right and walk down dirt path to the base of cliff on the flood plain of Cazenovia Creek. At bottom of path turn left and walk north for about 600 ft, following the base of cliff (swampy ground), to exposures along the west bank of Cazenovia Creek.
(1 1/2 hours): This east facing cliff provides an excellent, long section of the Windom/Genesee contact. The Genundewa Limestone is nearly at water level at the southern (upstream) end of this section; however, downstream about 1/10 mile some 2 m (7 ft) of Penn Yan and upper Windom shales are exposed beneath the Genundewa. Lowest beds, exposed in the creek floor, are the Penn Dixie pyritic beds of the upper Windom. Diagnostic small specimens of Tropidoleptus carinatus can be obtained in abundance at this location. Overlying beds contain a zone of distinctive ellipsoidal concretions, typically with pyritic cores. The Amsdell bed (unit 12) forms a prominent, light-gray weathering calcareous band about 1 m thick near the top of the Windom. Near the southern end of the section this bed forms a small waterfall in Cazenovia Creek. Note the absence of upper shales (unit 13) in contrast to Penn Dixie Quarry (Stop 1).
The contact between the Windom and the overlying Genesee is sharp and planar with little evidence for erosive scour. Four or five lenses of the Leicester Pyrite, ranging from 1-15 cm thick and up to 2 m across, occur along the Windom/Penn Yan contact at widely spaced intervals. The pyrite contains abundant, reworked, pyritic burrows, diminutive brachiopods, mollusks, fish bones and wood. One lens along this section exhibits interfingering with the black Penn Yan shale. Lower surfaces of the pyrite lenses exhibit parallel ridge and furrow marks suggestive of current scour of the underlying Windom muds. At this locality about 0.5 m (1.6 ft) of barren, black, laminated Penn Yan Shale overlies the Windom; the upper portion of this shale contains large septarian concretions that locally protrude up into the overlying Genundewa. The Genundewa forms a prominent overhanging ledge about 40 cm (15 in) thick. The lower surface of this ledge is undulatory and is marked by a veneer of encrinite, conodonts, carbonized wood, and abundant fish bones and rare hiatus concretions. This unit probably is correlative in part with the typical North Evans a few miles west of this locality. The upper contact of the Genundewa with the silty, dark-gray West River Shale is gradational. Lower West River beds here yield abundant Pterochaenia, wood, chonetids, pyritized goniatites and rare crinoid columns. Higher units exposed in the upper cliff face include the black Middlesex Shale and gray, concretionary Cashaqua Shale, members of the Sonyea Formation.

Northrup Road bridge over Cazenovia Creek.
Note falls in creek over the Tichenor Limestone of the basal Moscow Formation, just upstream (east) of the bridge. High cliffs visible in the distance, upstream from the falls, expose about 12 m (40 ft) of Windom shale, capped by the Genesee Formation. The Smoke Creek bed is near the base of the cliff. At the upper contact, the Amsdell bed has been largely eroded away.

Note exposures of black Rhinestreet Shale (upper Devonian).

STOP 3A. Buffalo Creek At Old Bull's Road Bridge.
(1/4 hour): From bridge, view exposures along Buffalo Creek. Downstream (north) and just south of new bridge a series of ledges crop out in the creek floor, representing a condensed upper Ludlowville/lower Moscow section; the lowest ledge is a basal bed of the Jaycox Member, followed by Tichenor Limestone, and calcareous ledges of condensed Deep Run, and basal remnant of Menteth Members followed by highly calcareous Kashong Shale Member. The Windom/Kashong contact, marked by scattered phosphatic nodules is exposed in the floor of the creek directly beneath the old bridge. Looking upstream (south), note high bank exposures of gray, lower Windom Shale. A light-weathering calcareous band about 4 m (13 ft) about the creek floor represents the Smoke Creek bed; concretionary shales beneath this level for about 1 m (3 ft) comprise a local manifestation of the Bay View Coral bed. Note the thickening of the lower Ambocoelia-rich shales, here about 3 m thick, compared to about 15 cm (6 in) at Penn Dixie Quarry (Stop 1). At the next stop we will see higher beds of the Windom Member, the lowest of which are slightly higher than the top of this cliff section.

STOP 3B Buffalo Creek, Upper Windom Shale Section.
(1 hour): This bank exposes about 5 m of upper Windom overlain by Genesee Formation. The lowest shales exposed in the creek bed contain abundant Zoophycos spreiten and thin layers rich in the chonetids, Pseudoatrypa, Mediospirifer, and other brachiopods. Pyritized fossils including nautiloids and one cluster of blastoid Hyperoblastus have been discovered at this level. These shales appear to represent the Big Tree fossil bed (unit 5). They are overlain by two or three horizons of large, flattened ellipsoidal concretions probably equivalent to the A and B limestone bands farther west. Large irregular masses of pyrite occur associated with these concretions. Above the concretions is an interval of friable, dark gray shales, with abundant pyritic burrow tubes and scattered pyritized nautiloids, nuculid clams, wood and other fossils, herein designated the Buffalo Creek pyritic beds (unit 8). The C,D and E limestone beds (units 9-11) are clearly visible in the upper part of the bank. At the far south end of the section it is possible to examine the upper contact of the Windom with the overlying Genesee. The last meter of soft shale immediately beneath the contact contains abundant, small Tropidoleptus diagnostic of the Penn Dixie beds (unit 12). Small ellipsoidal concretions just beneath the contact may correlate with those in the upper Penn Dixie beds at Cazenovia Creek. Note the absence of Amsdell and upper shale beds (units 13 and 14) in contrast to Cazenovia Creek and localities farther 'west. These upper units have been truncated prior to deposition of the overlying Penn Yan Member. Lenses of Leicester Pyrite are present at the contact in several locations, but are not readily accessible, although the Leicester can be observed in fallen blocks. The Genundewa Limestone ranges from 0 to 10 cm in thickness; Styliolina limestone and glauconite coated hiatus-concretions occur in depressions on an undulatory erosion surface at the top of a ledge-forming concretionary band 1.6 m above the base of the Penn Yan.

STOP 4 Little Buffalo Creek, Upper Windom Section.
(1 hour): This small creek exposes an excellent section of the Upper Windom, Leicester, Penn Yan Shale (here about 1.8 m thick) and Genundewa Limestone. Lowest exposures include the richly fossiliferous Big Tree bed in the Windom, slightly below a layer of flat concretions. This fossil bed yielded atrypids, Srinocyrtia and other species. The Buffalo Creek pyritic beds (unit 8) are well exposed in the floor of the creek upstream and here contain Devonochonestes coronatus and are Pseudoatrypa in addition to pyritic tubes and nautiloids characteristic of the bed farther west. The uppermost beds of the Windom include a band of argillaceous limestone followed by shale and irregular large septarian concretions. These units comprise the C and D limestone beds respectively. The upper E unit as well as the Penn Dixie beds are missing at this locality. In places, the septaria of unit D protrude upward and deform the basal Penn Yan Shale: lenses of Leicester Pyrite lap directly onto these concretions. Upstream from the Windom/Penn Yan contact a spectacular bed of grotesquely shaped concretions occurs in the upper Penn Yan Shale immediately below thin Genundewa Limestone. Here the Genundewa contains a basal veneer of North Evans lithology, including glauconite and pyrite-coated hiatus concretions. These concretions, characterized by internal lamination, have been completely disinterred from the Penn Yan and rolled into new orientations. This pre-Genundewa disconformity is believed to correlate westward with the North Evans limestone.

STOP 5A Cayuga Creek, Upper Windom Section.
Turn left into driveway just before intersection with Eastwood Road on right. Park at end of the drive and proceed on foot to lower section of Cayuga Creek. Walk back upstream toward Clinton Road bridge.
(1/2 hour): The upper 3.5-4 m (11-13 ft) of the-Windom Shale are exposed beneath the bridge. There are two zones of ellipsoidal calcareous concretions, separated by about 2 m (6.5 ft) of nearly barren pyritic fissile dark gray shale. The lower concretion band is well exposed in the creek floor north of Clinton Road; surrounding shales contain abundant small brachiopods and a pyritic fauna with large masses of pyrite. This interval resembles superficially the Buffalo Creek pyritic bed (unit 8) but is apparently coextensive with lower barren shales of unit 4 seen farther west.
An upper concretionary band occurs 15-30 cm (6-12 in) below the upper contact of the Windom. Shales immediately above this concretion level are highly fossiliferous and contain abundant chonetids, Mediospirifer, Spinocyrtia, Athyris and Pseudoatrypa. This band appears to be coextensive with the Big Tree bed (unit 5) and it may also represent a western remnant of the Fall Brook Coral bed seen in Genesee County and farther east.
The upper contact of the Windom is sharply defined and exhibits local truncation; the Big Tree bed is observed to approach the contact as it is traced northward along this section of Cayuga Creek. The Windom is abruptly overlain by black fissile shale (possible westward limit of the Renwick Member); it contains oriented Styliolina and patches of chonetid brachiopods. Large lenses of rusty-weathered Leicester pyrite occur at the contact near the Clinton Road bridge. These have yielded well-preserved pyritized wood, fish bones, and other fossils.

STOP 5B. Cayuga Creek, Lower Genesee Section.
Turn riqht into driveway on east side of bridge and park at end of drive. Walk to falls and remains of concrete dam across Cayuga Creek.
(1/4 hour): This section has been thoroughly described in previous field trip guidebooks (see Kirchgasser and Brett, 1981, p. 18). The Genesee Formation here includes 1.3 m (4.3 ft) of black and dark gray (Renwick?) Shale, followed by 1.8 m (6 ft) of gray, concretionary Penn Yan Shale. A prominent line of concretions occurs near the top of the section and is probably correlative with that seen in Little Buffalo Creek. A ledge of Genundewa Limestone about 20 cm (8 in) thick caps a low waterfall near the remains of an old concrete dam. The base of this ledge, again, contains encrinite and black hiatus concretions indicating an eastward extension of the North Evans type lithology associated with a pre-Genundewa erosional unconformity.

A2: CARBONATE FACIES OF THE ONONDAGA AND BOIS BLANC FORMATIONS NIAGARA PENINSULA, ONTARIO
Mary Rose Cassa
Gulf Research and Development Company
Pittsburgh, Pennsylvania
Don L. Kissling
ERCO Petroleum Services, Inc.
Houston, Texas
Devonian bioherms of the northern Appalachian Basin have been an important source of hydrocarbons since the 1967 discovery of gas from an Onondaga pinnacle reef in Steuben County, New York. Onondaga bioherms are represented in the outcrop belt by small organic buildups which have been studied for at least three-quarters of a century (Grabau, 1903; Stauffer, 1913,1915). More recent studies of these buildups and their components enable us to better understand the paleogeographic distribution of the buildups, their internal facies structure, and their importance in hydrocarbon exploration.

A2: CARBONATE FACIES OF THE ONONDAGA AND BOIS BLANC FORMATIONS NIAGARA PENINSULA, ONTARIO

Tonowanda Channel of Niagara River on right.
Grand Island is visible across the river, behind us. At the south end of Grand Island, the Tonowanda and Chippewa Channels join and Fort Erie, Ontario can be seen across the river.

Lock in Black Rock Canal on right.

STOP 1. Ridgemount Quarry
Hard hats must be worn. Please exercise caution near quarry walls; watch for overhangs and loose rock.
An excellent exposure of the Silurian-Devonian unconformity is found in the north wall of this quarry. Several small bioherms are exposed in the northern part of the quarry and in an "embayment" a few hundred feet west of the entrance. The mounds are characterized by abrupt thickening of lower Edgecliff strata which contain abundant solitary and colonial rugose corals, tabulate corals, and crinoid material (Figure 9). Dominant coral genera include Acinophyllum, Cladopora, Heliophyllum, Cystiphylloides, Syringopora, and Emmonsia. Internal structure is stratified; facies are represented as successive layers which pinch out laterally and drape over one another to give the characteristic mounded appearance. Stratified structure and absence of rigid framework indicate that turbulence was low during deposition. Biohermal strata contrast markedly with laterally equivalent and onlapping crinoidal packstone and wackestone beds of non-biohermal Edgecliff.
Sub-biohermal Strata
Mottled olive-gray Bertie Dolomite is unconformably overlain by 0.4 m of yellowish-gray conglomeratic Springvale Sandstone, containing large, flat dolomite clasts. The Bois Blanc consists of 3.2 m of light olive-gray, cherty, fine-grained limestone, containing trilobites, bryozoans, and abundant brachiopods. The mounds are separated from the Bois Blanc Limestone by a thin, shaly zone.
Biohermal Strata
The base of the larger mound sags markedly into underlying strata. Basal beds of the two mounds are similar, consisting of 0.2 to 0.5 m of yellowish-gray, crinoid packstone. Abundant in-place Syringopora and other corals are found in the basal beds of the smaller mound.
The overlying facies, 1.0 to 1.5 m of crystalline coral-crinoid packstone, can be traced between mounds. It contains Acinophyllum, Syringopora, Cladopora, Heliophyllum, and Cystiphylloides, as well as large crinoids whose columnals measure up to 2 cm in diameter. The smaller mound is capped by coral-crinoid packstone-grainstone, containing abundant Acinophyllum, common Heliophyllum, and sparse Cystiphylloides.
In the larger mound, the coral-crinoid packstone is overlain by 0.5 m of coral-dominated wackestone, which, in turn, is overlain by 0.5 m of packstone containing Acinophyllum and branching tabulate corals, Cladopora and Aulopora. Above that, Acinophyllum, Heliophyllum, and Cystiphylloides are found in coral-crinoid grainstone or packstone matrix. This facies is porous, with bitumen-lined interparticle and intraskeletal pores. The mound is capped by up to 0.5 m of crinoid-stylioline wackestone-packstone, containing few corals. Rare chert nodules in biohermal beds are light-colored and highly irregular in shape. Overlying the mounds are olive-gray, argillaceous crinoid-stylioline wackestone and mudstone, containing abundant dark chert nodules and many rugose and tabulate corals.
Non-Biohermal Strata
The overthickened, richly fossiliferous strata of the bioherms grade laterally into somewhat thinner, non-biohermal beds of the lower Edgecliff which consist of medium-grained crinoid grainstone and packstone containing few corals. This facies, approximately 0.8 m thick, is overlain by 7.6 m of crinoid packstone and grainstone which contain many Heliophyllum and Acinophyllum colonies. In his description of this locality, Oliver (1976) assigned these beds to the Clarence Member, perhaps based on the presence of chert nodules or on the darker, more argillaceous nature of laterally equivalent beds which overlie the mounds. Although the exposure could represent a local, fossiliferous facies of the Clarence, Oliver's (1976) suggestion that the Edgecliff and Clarence interfinger may be borne out here in the occurrence of light gray biostromal beds characteristics of the Edgecliff in association with darker olive gray, argillaceous beds containing fewer corals.

Battlefield and museum on right.
Plaque on museum building reads: "This house stood on the battlefield during the Fenian raid June 2, 1866. John Teal's family cared for the wounded soldier shot near the front verandah." Monument is memorial to "Queen's Own Rifles, 13th Hamilton Battalian Caledonian and York Rifle Companies of Haldimand in defense (sic) of country June 2, 1866."

Port Colborne Quarries, Ltd. to the north.
These quarries are floored in the Silurain Bertie Dolomite.

Robin Hood Flour mill is visible to the northwest.
Port Colborne is the second largest flour milling city in Canada.

Cross Welland Canal - Lock No.8.
The Welland Canal connects Lake Ontario (St. Catherines) with Lake Erie, an elevation difference of 99.5 m (326.5 ft). It was built in the early 1800's and had to be widened, straightened, and deepened several times as ships increased in size and traffic volume grew. This lock, the guard lock, was the longest in the world when it was built in 1933.

R.E. Law Crushed Stone Quarry on right.

STOP 2. Port Colborne West Quarry
Hard hats are optional. Please exercise caution near quarry walls, both from below and from above.
A portion of a broad biohermal bank is particularly well exposed in the east wall of this quarry (Figure 10). Original reconnaissance and detailed study were carried out here and in the R. E. Law quarry, approximately one mile north. The Law quarry is floored in Silurian dolomite and exposes Springvale and Bois Blanc strata, including greenish, Acinophyllum-rich beds of the upper Bois Blanc and lower Edgecliff, which represent initial stages of bioherm development. This southern quarry is floored in the upper Bois Blanc (Oliver, 1976). Lower Edgecliff strata are characterized by a coral assemblage which includes Cystiphylloides, Cylindrophyllum, and Heliophyllum. The tabular "core" facies contains a variety of colonial rugose corals and replaces bioclastic beds which are more characteristic of the Edgecliff. Massive favositid tabulate corals are more abundant in the upper, less argillaceous beds.
Glacially scoured surfaces are exposed around the perimeter of the quarry, particularly at the south end. The smoothed surfaces reveal glacial striations and offer spectacular plan-view exposures of the fossil bioherm community.
Sub-Biohermal and Bioherm-Equivalent Strata
Calcareous sandstone and sandy limestone and chert of the Springvale Member unconformably overlie the Bertie Dolomite (exposed in the Law quarry). Glauconite gives the Springvale its characteristic greenish color. Cherty, fossiliferous, fine-grained limestone makes up most of the remaining Bois Blanc, which is characterized by the brachiopod Amphigenia elongate (Telford and Tarrant, 1975; Oliver, 1976), in addition to rugose and tabulate corals, trilobites and bryozoans. The upper part of the Bois Blanc differs in consisting of greenish, shaly limestone which grades upward into overlying Edgecliff beds. Oliver (1976) drew the boundary between the formations based on occurrence of Acinophyllum species. Beds which contain A. stokesi and A. simcoensis are considered Bois Blanc; those containing A. segregatum are Edgecliff. He suggests that these units may represent the missing time interval between Bois Blanc and Edgecliff deposition elsewhere. The lithologic transition suggests that similar depositional conditions prevailed throughout late Bois Blanc and early Edgecliff sedimentation. Acinophyllum biostromes which developed under these conditions represent incipient stages of bioherm development.
Biohermal Strata
Two thin (20 cm) beds of Acinophyllum bafflestone mark the earliest phases of Edgecliff bioherm development. These beds and argillaceous limestone containing diverse coral fauna, including rugose corals, Cystiphylloides, Cylindrophyllum, Heliophyllum, and the tabulate favositid coral Pleurodictyum, are exposed in Law quarry and in the northern part of the inactive (southern) quarry. Total thickness is 4.2 m. Overlying are 0.8 to nearly 2.0 m of massive, light-colored limestone dominated by Acinophyllum in association with rugose corals, Cystiphylloides and Heliophyllum, tabulate corals, Favosites and Emmonsia, and sparse stromatoporoids. Intraskeletal porosity is well-developed; black bitumen stains are common. Matrix consists of crinoid grainstone and packstone and contrasts markedly with that of the underlying, more argillaceous Cystiphylloides and Acinophyllum beds.
The massive-bedded Acinophyllum facies is overlain by 7.6 m of medium-bedded packstone, wackestone and grainstone which contains a varied and abundant fauna, including colonial rugose corals, Acinophyllum and Heliophyllum; solitary rugose corals, Cystiphylloides and Siphonophrentis; massive tabulate corals, Favosites, Lecfedites, and Emmonsia; branching tabulates, Cladopora, Thamnopora, Syringopora, and Aulopora; and laminar stromatoporoids. Crinoid debris is abundant; brachiopods are sparse. Thin sections from the upper 4 m of the buildup reveal abundant fenestrate and encrusting bryozoans, the latter occurring in association with crinoid holdfasts. Chert is common throughout the section, but is absent from the Acinophyllum and Cystiphylloides beds. The buildup is overlain by argillaceous, sparsely fossiliferous mudstone of the Clarence Member, characterized by abundant dark chert nodules.
Vertical extent of the buildup cannot be determined exactly, but a thickness of about 10 m is estimated. Estimating lateral extent is even more difficult, due mainly to the tabular nature and lack of "typical" biohermal zonation and distinct flank facies. Although the position of the exposure in relation to the buildup as a whole is known, absence of bioherm facies in the Law quarry suggests the buildup is on the order of 1 km broad.

Large, stabilized sand dunes on right.

Dunes migrating over road surface.

Sugarloaf Hill on right.
This dune rises more than 100 ft above lake level and has been a landmark to Lake Erie travellers since the days of the earliest explorers.

Bridge over drainage canal.

View of Port Colborne's harbor and Welland Canal's port of entry.
The park offers a view of Port Colborne's harbor and the Welland Canal's port of entry. Over 6,600 ships and nearly 800 pleasure craft passed through the canal in 1980. Inco Metals' Company nickel refinery is Port Colbornel's largest employer. Canadian nickel, in Inco-developed alloys, was used in the main engines and other components of the space shuttle Columbia.

STOP 3. Port Colborne East Quarry
Rubble pile on right. Park on concrete pad just beyond. Walk SW into abandoned quarry complex.
No detailed studies of this quarry complex have been published since the days of Stauffer (1915). It was once operated by the Canadian Portland Cement Company and included a large plant, of which only the foundations remain. The quarries were developed on a low, ENE-trending anticline. Telford and Tarrant (1975) mapped only Edgecliff at this locality, however, in places, strata have a distinctively Clarence character _ argillaceous, fine-grained, abundant chert - particularly in the north and west walls. This is probably another manifestation of the interfingering nature of Edgecliff and Clarence facies as described at the Ridgemount quarry. Beds at water level are packstone or grainstone; skeletal material decreases and mud increases upward. The "island" in the southern end of the quarry is a bioherm. Large blocks of light-colored Acinophyllum bafflestone are piled to the east of the island, along the roadway which leads southward into the quarry. Near the island, a railroad trestle crosses a cut which connects the northern quarry with a smaller one south of the tracks. In this area are exposed approximately 4 m of massive bedded, light gray, crinoid grainstone and packstone containing abundant large favositids, common Cystiphylloides, and fewer Thamnopora and Syringopora. These strata have all the aspects of proximal flanks observed in the subsurface bioherms. This stop offers excellent fossil-collecting, either from the rubble piled east of the quarry, or from around the quarry itself. As at the western quarry, glacially-smoothed surfaces provide two-dimensional exposures of the fossil bioherm community.

A3: EURYPTERIDS, STRATIGRAPHY, LATE SILURIAN-EARLY DEVONIAN OF WESTERN NEW YORK STATE AND ONTARIO, CANADA
Samuel J. Ciurca, Jr.
The eurypterid horizons of the Bertie Group in New York State (Ciurca, 1973, 1978a) continue into adjacent Ontario, Canada bearing their distinctive eurypterid faunas (Ciurca, 1967a,1976). In addition, Helderbergian strata (Clanbrassil Fm.), between Byng and Haggersville, show the presence of post Bertie-Akron strata in this region in a manner analogous to that of the Honeoye Falls Fm. described for similarly positioned strata discovered south of Rochester, New York (Ciurca, 1967b, 1973).
The purpose of this paper is to present a preliminary account of the stratigraphy and paleontology of this interesting eurypterid-bearing sequence of rocks and to stimulate research into the origin and significance of the waterlimes and associated lithologies in which eurypterids are peculiarly characteristic and abundant.
STRATIGRAPHY AND PALEONTOLOGY
Detailed field studies in New York and Ontario, Canada were undertaken with the hope of providing a better framework for understanding the occurrence and distribution of eurypterid faunas and waterlimes in the regions, and to facilitate correlation. In these studies, the waterlime units have been utilized as the basis of a stratigraphic framework. They have been given an importance similar to that given coal beds in cyclothemic sequences and it is hoped that this will help tracing and understanding of the cyclic sequences present in our Late Silurian-Early Devonian rocks. The distribution of the waterlimes of the Bertie Group, and of the new stratigraphically higher waterlimes, is shown in Figure 2. Heretofore, the only well known waterlime was that of the Williamsville from which much of the eurypterid material in collections was knowingly or unknowingly obtained (i.e. Eurypterus remipes lacustris Fauna).

STOP 1. Dunnville Rock Products, Ltd.
Quarry at Byng, Ontario, Canada. This quarry produces "crushed aggregates-concrete stone, Armour rock for shoreline protection, clay fill".

STOP 2. Port Colborne Quarries, ltd.,
Quarry at Port Colborne just north of Route 3

STOP 3. Ellicott Creek
Ellicott Creek at Wiliamsville, just north of NY 5 (called Glen Park).

A4: GLACIAL GEOLOGY OF THE ERIE LOWLAND AND ADJOINING ALLEGHENY PLATEAU, WESTERN NEW YORK

Niagara Falls morainal ridge on right, Lake Tonawanda plain to left.
Cross Hopkins Rd. with slight rise of Niagara Falls morainal ridge on right, Lake Tonawanda plain to left.

Subdued hillocks of Niagara Falls Moraine
Turn right (south) onto Harris Hill Rd. with subdued hillocks of Niagara Falls Moraine partly mantled by Lake Warren silts. Rise up Onondaga Limestone Escarpment.

Sandy soils on Escarpment edge
Sandy soils on Escarpment edge here result from winnowing of older sediments by Lake Dana waters.

Descend Escarpment into river embayment at Clarence Village.
Recent U.S. Geological Survey borings suggest that a large buried (drift-filled) valley connects the embayment southward with the present valley of Ellicott Creek near Stop 1.

Rise south back up Onondaga Escarpment onto gravel plain
Turn right onto Ransom Rd. Rise south back up Onondaga Escarpment onto gravel plain related to Buffalo Moraine and deposited in Lake Warren III. Beaches of lower stage-Lake Grassmere occur along Escarpment crest.

STOP 1. Pine Hill Gravel Pit.
Pit is cut into a portion of the Buffalo Moraine and is just on north margin of present northwest-flowing Ellicott Creek. Borings made for the study of the gravel aquifer (Fig. 6) in this area show two till sheets with sand and gravel between. This and several adjoining excavations expose the thick sand and gravel units deposited in at least 30 m (100 ft) of Lake Warren III or earlier stage. Thin red lake clay partings separate thick rippled sand units (varves?). The overlying till and sand/gravel unit shows evidence of flow and deformation (often irregularly interfingering). The till, laid down by thin, sometimes bouyant ice margin, can be traced at least to the Alden Moraine ~5 mi to the south. Fabrics show moderate NE-SW maxima.

Drive along crest of subdued sandy beach or offshore bar of Lake Warren III.

Bend right on Peters Corners Rd. onto strong Warren III beach ridge.
This strand can be traced intermittently to Syracuse and south and west through Cleveland into Michigan.

Pit on right excavated in beach ridge.
Pit on right excavated in beach ridge. Cross several beach ridges obliquely.

Alden Moraine at left
Cross R.R. bed cut in Alden Moraine at left (source of beach material) and turn right onto North St. following a Warren III beach (moraine on left).

Cross highest beach ridge of several oblique to Sandridge Rd.

Cross several ridges-spits of Warren III.
Turn right (west) at W. Alden onto Broadway (Rt. 20) and cross several ridges-spits of Warren III. This is the area where Warren III beaches split off northward and Warren I and II? terminate south of Alden Moraine.

Turn left onto Four Rod Rd., still crossing Warren ridges.

Descend into floodplain and cross Cayuga Creek.

Rise across washed till (strand of Lake Warren I - highest Warren)
Rise across washed till (strand of Lake Warren I - highest Warren) at white farmhouse (~860 ft [262 m]) and proceed south across Marilla Moraine. Moraine appears unaltered by Lake Whittlesey waters and hence formed before or soon after draining of Whittlesey to Warren I level.

Cross Clinton St. going south, still on Marille Moraine.

STOP 2. Drainageway Marilla-Hamburg Moraines.
View small esker and associated kames to northeast. To west of intersection, Bullis Rd. crosses delta surface formed in Lake Whittlesey and subsequently Lake Warren by water draining along ice margin here.

Cross Hamburg Moraine

Not good till cut at far left along Little Buffalo Creek.

Moulin kame hillock on right behind farm
Moulin kame hillock on right behind farm consists of till and poorly sorted gravel. A few similar forms occur just to east out of sight.

Go west to stop sign (in E-W-oriented meltwater channel).

Cross Meltwater Channel

Cross Buffalo Creek--its post-glacial position?

Many gravel hillocks of moraine have been removed here.

Note deep cut in moraine.

Deep kettle hole and lake on left
Deep kettle hole and lake on left; hummocky ice-contact drift at distal side of Hamburg Moraine.

East Aurora Waterworks.
This is within partly buried valley of Preglacial Cazenovia River which trends northward through the Hamburg Moraine. Valley fill is major water source and buried valley a collector/ conduit of groundwater.

Note postglacial Cazenovia Creek has been deflected to westward path.

Note U-shaped valley cross-section modified by alluvial fans at margins.

STOP 3. Emery Park (Lunch Stop)
The Gowanda Moraine crosses the valley at this point. The park is on the west wall of the partly buried valley (~60-l00 m of drift till) now occupied by East Branch Cazenovia Creek. Ice flow was approximately parallel to this and adjoining valleys. High level deltas graded to proglacial "finger lakes" line the east valley wall in this general area.

Cross East Branch Cazenovia Creek.
Creek is on bedrock at right, deepest part of valley is to left (east) of bridge. Pass through Village of Holland and rise southward onto proximal side of Lake Escarpment Moraine (bedrock actually fills slightly southward).

Turn right onto Hand Rd. at crest of Lake Escarpment Moraine.

Turn around at Chaffee solid waste disposal site (landfill).
Although tills appear quite thick and dense here, the Chaffee Outwash Plain heads at north margin of the current landfill boundary and critically close to leachate drainage.

Note meltwater channels on right
Note meltwater channels on right leading to head of outwash plain within few tenths of a mile.

Cross Grove St., Chaffee, on outwash plain.
Note irregularly south-sloping surface, probably effected by differential settling. A nearby gas well reached bedrock at about 188 m (615 ft) depth (see Calkin and others, 1974).

Nichols Brook site (Calkin and McAndrews, 1980) on left.

Pass out of Preglacial Cazenovia Valley toward Arcade.

STOP 4. Arcade Section.
The stratigraphy at this active cut-bank of Cattaraugus Creek is shown in Figure 4. The locality is south of the Lake Escarpment Moraine. At least three till units are exposed, separated by glacial lake deposits. The upper till is thin and has textural properties strongly influenced by underlying lacustrine deposits and appears to indicate deposition from thin ice. The lower tills are thicker and generally more homogeneous in their properties although the lowest unit carries clasts of red till and clay. The tills are tentatively correlated with Hiram, Lavery, and Kent drifts on the basis of sequence.

Hesitation Stop - Gernatt Gravel Pit
Good exposure (when working) of Chaffee Outwash at Cattaraugus Creek where it overlies till (generally not exposed but just above creek level). Near-horizontally bedded and very well sorted gravel overlies steeply inclined (foreset) units which on one visit appeared to be associated with till units.

Cross bedrock-cored ridge dividing buried valley into two channels.
Deepest channel is on west side and connects valley to south of Cattaraugus Creek with present valley of East Branch Cazenovia Creek Valley (not with Buffalo Creek [Calkin and others, 1974]).

Descend from outwash surface into Cattaraugus Creek Valley.
Bluemont Ski area to south across creek.

Note slumped till of Lavery Till on right
Note slumped till of Lavery Till on right, Lord Hill Section of LaFleur (1979, 1980) on left at Creek. Strong fluvial dissection exposes till and lake sediments in the valley area.

Rise out of postglacial valley onto outwash
Rise out of postglacial valley onto outwash tied to Springville Outwash Plain. Lake Escarpment morainal ridges are to north.

Descend into spillway that drained pro-glacial lake
At hospital, descend into Village of Springville occupying spillway that drained pro-glacial lake in North Branch Eighteenmile Creek and West Branch Cazenovia Creek. This is center of Preglacial Buttermilk Creek heading several miles to south.

Proceed straight (west) on Rt. 39.
(The most scenic route would trend left via Waverly St. and Zoar-Gowanda Rd. but roads are narrow and steep, and bridge weight limits prohibit bus traverse.)

Leave outwash plain crossing onto distal ridge of Lake Escarpment Moraine.

Cross onto outwash plain
Cross onto outwash plain (still on Rt. 39) at head of South Branch Eighteenmile Creek. Formed by meltwater of Lake Escarpment Moraine shed southward into buried Preglacial Connoisarauley River Valley.

Rise off outwash onto Lake Escarpment Moraine as it trendsN-S.

Cross onto gravel valley till
Cross Rt. 75 at Collins Center and onto gravel valley till (underlain by lake clay and till respectively).

Cross Gowanda Moraine.
Stratigraphic sections suggest moraine formed as ice advanced into proglacial lake.

Clear Creek Valley (part of Preglacial Allegheny Valley)
Turn left (south) onto Rt. 62 within Clear Creek Valley (part of Preglacial Allegheny Valley) and park near corner. Reach exposure downstream from highway bridge 0.3 mi south.

STOP 5. Gowanda Hospital Interstadial Site
This site exposes three till units, a buried paleosol and overlying organic horizon. It is briefly described in the text and Figures 3a, b, and c. The right bank section is rarely exposed but the paleosol and wood horizons on the left bank are often clear after minor work. One of the most important aspects of the site is the Gowanda Paleosol, a buried, truncated (of its A horizon) soil whose substantial development and stratigraphic positioning appears to argue for a long mid-Wisconsin nonglacial interval prior to about 50,000 yr BP (Calkin and others, 1982).
One of the many problems of the stratigraphy is the age and correlation of the brown till unit. The till material appears to be derived locally by glacial erosion of the underlying, weathered red "Collins" till and therefore it is difficult to correlate regionally with other till units. Although it displays mudflow-like contacts with the channel gravel, it also shows good glaciotectonic structures including wood sheared from underlying deposits. The age of the wood suggests a mid-Wisconsin ice advance; however, there is some question whether the ice sheet reached past this area to Titusville, Pennsylvania, in Middle Wisconsin interval as suggested by current correlations (Figs. 2 and 3b).

Rising onto Fairchild's (1932) Asylum Terrace
Turn left (west) onto Richardson Rd. rising onto Fairchild's (1932) Asylum (Gowanda State Hospital) Terrace graded to a local proglacial lake in the Cattaraugus Creek (Preglacial Allegheny) embayment of the Erie Basin. This surface is an extension of top gravel unit (8) at Gowanda Hospital site.

View at left of Fourmile Level, a delta surface
View at left of Fourmile Level, a delta surface (on Cattaraugus Indian Reservation) formed in Lake Whittlesey and later Lake Warren.

Gravel pit at right displays large foreset bedding
Gravel pit at right displays large foreset bedding units in thickened section of Asylum Terrace seen at the Gowanda Hospital site (Fig. 3a, unit 8).

Proceed north with Gowanda Moraine parallel to right.

Zone of weak strand lines
Rt. 62 follows along zone of weak strand lines of Lake Whittlesey and Lake Warren I. Lowland on left is an old buried tributary valley of Allegheny River.

Cross Winter Gulf and organic site on left
Cross Winter Gulf (unofficial name) and organic site on left (Schwert and Morgan, 1980; Calkin and McAndrews, 1981). The section here is diagramed in Figure 5.

Cross gravelly ridges (before low point)
Turn left onto Milestrip Rd. (just south of a "Friends" cemetery built on a delta of Lake Whittlesey). Cross gravelly ridges (before low point) intermediate between Whittlesey and Warren (possibly Arkona?). Note ridge-spit extending from west (on right) graded first to Lake Whittlesey and later modified by Lake Warren waters.

Spit extending eastward is tied to Whittlesey beach
Spit visible (again) extending eastward is tied to well-developed Whittlesey beach (visible on left) which completely encloses bedrock-based high area here (plateau outlier).

Cemetery at intersection spans a Warren ridge.

STOP 6. North Collins, Whittlesey Beach Exposure
The Glacial Lake Whittlesey beach with crest at 850 ft (260 m) here is almost totally composed of shale, eroded from the local bedrock (Calkin, 1970, Fig. 2). The good development of the ridge on this narrow-embayment-side of the island in Lake Whittlesey is of interest. Lake Whittlesey extended southwest beyond Toldeo and into the Huron Basin. Several ridges of Lake Warren occur below the Whittlesey ridge; many have been destroyed by years of farming or construction.

Proceed east (off Whittlesey island)

Rt. 62 follows along Lake Warren beach ridge.
Turn left (north) at Rt. 62 (intersection at North Collins is on delta deposits of Lake Whittlesey). Rt. 62 follows along Lake Warren beach ridge. Lake Whittlesey beach is visible intermittently on incline to right (east), lower Warren ridges to left with deeper water silts and clays.

Whittlesey beach and wave-cut cliff exhumed in old gravel pit at right.

Lake Warren beach ridges exposed in gardens on either side of road.

Cross South Branch Eighteenmile Creek.
This and similar cuts are apparently post-glacial gorges.

View to right (northeast) of wave-cut beach and bluff of Lake Whittlesey.

Cemetery on right and road itself still on Lake Warren beach.

Onondaga Escarpment
Pass under Rt. 5 and through Onondaga Escarpment. Note south dip of strata. This was formerly a prize fossil collecting quarry.

B1: STRATIGRAPHY AND FACIES VARIATION OF THE ROCHESTER SHALE (SILURIAN: CLINTON GROUP) ALONG NIAGARA GORGE
University of Rochester, Rochester, NY 14627
The linear, east-west configuration of Paleozoic outcrop belts in western New York and Ontario imposes a strong two-dimensionality on our knowledge of the stratigraphy and facies relationships of these rocks. It is frequently assumed that the outcrop sections provide a reasonable transect from near shore clastic-dominated facies in the east to offshore carbonates and marine muds in the west. This view is overly simplistic and it ignores the fact that the Paleozoic epeiric seas had a northern as well as an eastern shoreline (directions based on modern geography). Furthermore, the idea of a simple east-west transect is contradicted by detailed examination of stratigraphy in western New York. Stratigraphic sequences such as the Silurian Clinton, Lockport, or Salina Groups exhibit vertical facies changes, manifest in the gradational contacts between beds, members, or formations. Walther's law predicts that such vertical sequences of litho- and biofacies should mirror arrays of laterally adjacent, contemporaneous facies belts. However, lateral gradation of lithologies is rarely observed along the outcrop belt of western New York. Rather, one observes that thin stratigraphic units representing distinctive facies, are traceable along the strike of the outcrop belt for tens to hundreds of miles (see, for example, Belak, 1980).
This "layer cake" aspect of New York stratigraphy has facilitated local correlation. However, it has also led to a common impression that the strata represent vertical stacking of time parallel facies units in a three dimensional sense, implying basinwide environmental changes. This non-Waltherian view of western New York stratigraphy is probably erroneous and it has greatly hampered attempts to decipher facies relationships and depositional environments. I contend that it is largely an artifact resulting from the east-west trend of the modern outcrop belts.

B1: STRATIGRAPHY AND FACIES VARIATION OF THE ROCHESTER SHALE (SILURIAN: CLINTON GROUP) ALONG NIAGARA GORGE

Begin road cut in Lockport and Rochester formations.

STOP 1. Lockport Junction Roadcut.
Exposure of upper Rochester/DeCew Dolostone contact. Pull vehicles off in parking area on left side of road.
The first two stops of this trip provide an overview of the Rochester Shale in eastern Niagara County, for comparison with Niagara Gorge sections farther west. This exposure illustrates the gradational upper contact of the Rochester Shale with the overlying DeCew dolostone. The upper 3-4 m of the Burleigh Hill Member of the Rochester Shale are exposed at the base of this cut. Nearly barren, friable, calcareous shale grades upward into a 1-2 m interval of interbedded dolomitic shale and buff weathering, burrow-mottled layers of argillaceous laminated calcisiltite. These beds appear to be gradational into the overlying DeCew Dolostone. This transitional upper Rochester unit thickens eastward to form the Gates Member which is recognized near the type section at Rochester, New York. The upper portion of the roadcut exposes an excellent section of the Gasport Formation (Lockport Group) and the sharp contact between the DeCew dolostone and the cross-bedded, crinoidal biosparites of the Gasport.
The uppermost Rochester and DeCew are interpreted as rapidly-deposited carbonate silt and clay sediments, winnowed from Gasport crinoidal shoals which lay nearby to the northwest. Cross lamination and abundant soft sediment deformation in the OeCew suggest rapid influx of sediment followed by dewatering. Body fossils are exceedingly rare in the upper Rochester and the DeCew, but burrows, including Chondrites, Planolites and Teichichnus are abundant. This may,again,reflect high turbidity.

Small exposure of Gasport Limestone.

STOP 2. Thrall Roadcut, Cambria, New York.
High cutbank in Rochester Shale and Lockport Group, in pasture along south side of Thrall Road. Park vehicles on right hand side of road, in front of driveway to farm.
Although somewhat weathered,this exposure provides a good reference section for the middle Rochester Shale in eastern Niagara County. Here the upper 4 or 5 m of the Lewiston Member, and its sharp contact with the overlying Burleigh Hill are exposed. Although largely covered by slumped talus, limestone ledges of Lewiston submember E ("bryozoa beds" of Grabau, 1901) protrude from the bank in several locations. This is an excellent locality for collecting the diverse fauna of middle Rochester beds. Weathered talus at the base of the slope has yielded over 20 species of brachiopods. corals, gastropods and complete thecae and crowns of Stephanocrinus, Caryocrinites, and various crinoids. Weathered slabs of limestone replete with ramos and fenestrate bryozoans are abundant here. Note the sharp contrast with the overlying barren mudstone of the Burleigh Hill Member. Thin calcisiltites comprise the only interbeds in this upper portion of the Rochester. Weathered slabs from the upper bank have yielded abundant trilobite remains (Dalmanites, Trimerus), ostracodes, Tentaculites and crinoid columnals. However, the bulk of the interbedded shale is very sparsely fossiliferous, in marked contrast to the underlying Lewiston beds. The top of this section is again capped by buff weathering DeCew Dolostone and Gasport Limestone.

We are now riding along the base of Niagara Escarpment.

Proceed up low ridge on Irondequoit Limestone
Proceed up low ridge formed by lower platform of Niagara Escarpment on Irondequoit Limestone.

STOP 3. Baer Roadcut.
Roadcut in Rockway and Irondequoit Limestones. Park near south end of cut.
There are very few outcrops in Niagara County where the basal beds of the Rochester Shale can be examined. This will be a brief stop to observe the uppermost Irondequoit Limestone which immediately underlies the Lewiston Member. Here the Irondequoit is a crinoidal biosparite, similar to the Gasport Limestone. Well-preserved fossils occur sparingly in the upper Irondequoit, including thecae of Stephanocrinus, Caryocrinites and other echinoderms. Small, white-weathering bioherms composed of fistuliporoid bryozoans and bound biomicrite occur near the top of this exposure. Such small bioherms occasionally protrude upward into the basal beds of the Rochester Shale.
Continue southward along Baer Road crossing the small plateau on Irondequoit Limestone and then up the main Niagara Escarpment.

Small exposure of Gasport Limestone at turn in road.

The classic Pekin roadcut through a Gasport bioherm
The classic Pekin roadcut through a Gasport bioherm is exposed along 429 immediately below Upper Mountain Road at this locality.

Excellent view off Niagara Escarpment onto Ontario Lowlands Plain.
On clear days this affords a view of Lake Ontario.

View to right out to Ontario Lowlands Plain and Lake Ontario.

Reservoir for Robert Moses Hydroelectric Plant appears as bank on left.

STOP 4. North End, Niagara Gorge Near Lewiston, New York.
Pull off on broad shoulder of Robert Moses Parkway and park at 55 mph sign. Passengers will disembark here, proceed over guard rail and down a slope, bearing to the right or north to cliffs along Niagara Gorge (see Fig. 7 point A).
Cliffs along the east face of Niagara Gorge between Lewiston Queenston Bridge and the Robert Moses Power Plant provide an excellent section of the entire Irondequoit, Rochester, and lower Lockport units. Here the Rochester Shale is approximately 17 m thick; the lower half comprises the Lewiston Member which consists of about 8.7 m (28.6 ft) of medium to brownish gray calcareous shaley mudstone with interbedded thin carbonates. The member exhibits a gradational lower contact with Irondequoit Limestone, but is sharply differentiated from the overlying Burleigh Hill Member at the top of a 1-2 m interval of bryozoan rich limestones (unit E). As at most localities in western New York and adjacent Ontario the Lewiston Member can be subdivided into six informal units or submembers designated by letters A-E. All of these beds are readily accessible in this cliff section and will be described as follows:
A) The basal transition zone of the Lewiston is up to 1 m thick and consists of dark-brownish to ashy-gray, silty, very calcareous and fossiliferous mudstone with interbeds of argillaceous limestone (biomicrite and/or biosparite). Brachiopods are very abundant and may be packed into layers; characteristic species include: Atrypa reticularis, large Leptaena rhomboidalis, Whitfieldella oblata and Plectodonta transversalisalis. Bryozoans are less common than in overlying beds, but laminar fistuliporoids are not uncommon. Echinodenn debris is abundant in the lower shales and unit A has yielded certain unique forms including a high, narrow morph of Stephanocrinus anulatus, large Eudalyptocrinites and the very rare crinoid Paracolocrinus (Brett, 1978).
Locally, small bioherms 1-5 m across and up to 2 m high protrude upward from the Irondequoit Limestone into the base of the Rochester shale (Sarle, 1901). These mounds are composed of whitish to massive micritic limestone with abundant laminar fistuliporoid bryozoans. A particularly good example of one of these mounds, now inaccessible, but readily visible, occurs along the high wall of Irondequoit Limestone immediately south of this Rochester Shale outcrop. This mound appears to interfinger laterally with shales of unit A; however, it al so contains pockets filled with a greenish clay shale, unlike the basal Rochester. Bioherms such as this have yielded a number of unique fossils not seen elsewhere in the Rochester Shale. Large Bumastus and Calymene trilobites, sometimes as coquinites of cephalic and pygidial shields occur in shaley pockets within the bioherms. Unit A clearly exhibits features transitional between typical Irondequoit Limestone and Rochester Shale.
B) The lower beds of the Rochester Shale grade upward into a 2.5 - 3m interval of softer, less calcareous, medium to brownish-gray mudstone with numerous lenticular beds of bryozoan rich biomicrites. As a whole, this interval is richly fossiliferous; although some mudstone beds are nearly barren. Ramose bryozoans are particularly characteristic and they frequently occur in clusters packed in a mudstone matrix. Associated with these clusters are abundant brachiopods such as Atrypa reticularis, small Leptaena, and Whitfieldella. This interval is particularly notable for the abundance of echinoderm remains including thecae of the blastoid-like pelmatozoan Stephanocrinus angulatus, and the rhombiferan cystoid Caryocrinites ornatus, both of which are typically associated with bryozoan-rich patches. Holdfasts of Caryocrinites are commonly found cemented to bryozoans. Gastropods, the trilobites Bumastus, Arctinurus, Dalmanites and others are also abundant in these beds. Certain limestone lenses in unit B appear to represent starved ripples of storm-concentrated, skeletal debris. Rotated geopetal structures and infillings of brachiopod shells with matrix identical to that of the underlying beds suggest derivation of these fossils by reworking during storms.
C) Near the north end of Niagara Gorge the middle interval of the Lewiston Member consists of about 3-4 m of sparsely fossiliferous gray shales and interbedded dark-gray, burrowed, laminated calcisiltites (pelmicrites). Bryozoan clusters and biomicritic limestones are absent from this interval. These shales exhibit a low diversity fauna dominated by the brachiopods Striispirifer, Strophonella and Parmorthis and the trilobites Dalmanites, Trimerus and Arctinurus. Near the base of unit C occur thin horizons which locally contain exceptionally well-preserved fossils. These layers, in all about 10-20 cm thick, were designated the Homocrinus band at Lockport, New York (Ringueberg, 1888); they contain the characteristic minute inadunate crinoid Homocrinus parvus, as well as completely articulated specimens of Asaphocrinus and Macrostylocrinus, the cystoid Caryocrinites, edrioasteroids and rare starfish. These fossils are associated with dense bedding plane assemblages of Striispirifer and other brachiopods. Such assemblages suggest rapid smothering of the sea floor by muds, producing catastrophic (live) burial of benthic communities by storm-generated mud layers (Brett, 1978; 1980)
Homocrinus-bearing layers have been recognized at Niagara Gorge about 4.6 m (15 ft) above the base of the Lewiston Member. However, no large assemblages have as yet been obtained from this locality. Calcisiltites of Lewiston C also appear to record a type of storm-generated layer. These units form thin (1-2 cm) persistent bands. Weathered surfaces reveal fine plana- and hummocky- cross lamination, often in alternating sets. Their upper surfaces may be rippled and basal contacts are invariably sharp. The undersurfaces of some calcisiltites yield abundant sole marks including flute and groove molds which suggest current scouring of cohesive muds; occasionally, well-preserved fossils may also occur on the undersides of these beds. Most calcisiltites are barren of body fossils, but they contain abundant trace fossils including large vertical shafts - possibly escape burrows - and post-depositional mining structures such as Chondrites and Planolites.
Rochester calcisiltites closely resemble storm silt layers described by Reineck and Singh (1972), from the modern North Sea and by Kreisa (1981) from the Ordovician Martinsburg Formation. They are interpreted as deposits from storm-generated density currents which transported carbonate silts from shallow platform areas into the Rochester depositional basin.
D) Overlying unit C is an interval, up to 2 m thick, of fossiliferous mudstone with biomicrites which closely resemble unit B, both in lithology and fauna. Again, clusters of ramose bryozoan are abundant and exhibit virtually all of the associated fauna found within the lower unit B. These beds, again, yield abundant atrypids and Whitfieldella, Striispirifer, Leptaena, Bumastus trilobites, dendroid graptolites and the pelmatozoans Stephanocrinus angulatus and Caryocrinites. Lenticular calcarenites resembling those in unit B become increasingly abundant upward in unit D whereas barren calcisiltites are less frequent than in unit c.
E) "Bryozoa beds." The top of the Lewiston Member is marked by a series of thin lenticular limestones (biomicrites and biosparites) interbedded with soft, gray, fossiliferous shale. Grabau (1901) termed this unit the "bryozoa beds," because of the great abundance of ramose and fenestrate bryozoans which constitute a bulk of the thin limestones. Brachiopods and echinoderms are also abundant in these beds although typically disarticulated and fragmented. Notable is the reappearance of a large, slender morphotype of Stephanocrinus seen also in unit A at the base of the Rochester Shale.
The uppermost bed of unit E is generally somewhat thicker and more continuous than the underlying layers and may be richer in brachiopod valves and crinoidal debris, resembling the uppermost layers of the Irondequoit Limestone. This unit marks the top of the Lewiston Member in nearly all localities. Locally, this topmost limestone bed is glauconitic and contains shale intraclasts, evidently derived by erosion from the underlying beds.
At this locality, as in most areas of western new York, the Lewiston Member is abruptly overlain by medium to dark gray platy and calcareous shale of the Burleigh Hill Member, named for exposures along Burleigh Hill Drive in St. Catharines, Ontario (Brett, in press). In the north end of Niagara Gorge the Burleigh Hill is about 10 m thick. However, as will be noted, this unit thins rapidly southward along Niagara Gorge. The basal 4-5 m of the member are sparsely fossiliferous to nearly barren, laminated and platy shales which weather into elongate slabs. Lithologically and faunally this portion of the Burleigh Hill Member most closely resembles unit C of the Lewiston Member, and, as with the latter unit, these shales contain occasional thin, laminated calcisiltites which increase in frequency upward. No bryozoan biomicrites have been observed in the Burleigh Hill Member at any locality in western New York and bryozoans are generally absent. Near the base of the Burleigh Hill are a few thin shell layers composed chiefly of the brachiopods Fardenia, Parmorthis, and Strophonella as well as trilobite fragments.
The upper half of the Burleigh Hill Member is gradational into the overlying DeCew Dolostone. Bands of calcisiltite become more closely spaced and eventually merge into a silty dolomitic shale near the top. A few thin layers near the top of the Burleigh Hill have yielded local patches of well-preserved crinoids including Dimerocrinities and Dendrocrinus as well as brachiopods and other fossils. Burleigh Hill dolomitic shales appear to pass upward gradationally into the overlying DeCew Dolostone Formation. Unlike the Lewiston member, which appears to represent a subsymmetrical cycle, Burleigh Hill reflects a shallowing-upward hemicycle.

Route Revision
2011: The Robert Moses Parkway has been interrupted and modified, so the route in the Guidebook is no longer possible. However, it is now possible to make left turns off of the Parkway... OHM

Goat Island Dolostone
Small exposures of Goat Island Dolostone of the Lockport Group in the roadcut.

STOP 5. Niagara Sewage Pumping Station.
Proceed on foot down old access road to Niagara sewage pumping station in the Gorge. Note well-exposed bioherm in the Gasport Limestone along roadcut.
This stop illustrates the contrast between northern and southern sections of Rochester Shale in the Niagara Gorge. A large artificial cut behind the new sewage pumping building exposes the upper portion of the Lewiston and the entire Burleigh Hill Members of the Rochester Shale. At this location in the gorge the Lewiston Member is approximately 12.5 m (41 ft) thick; the majority of this thickness consists of unfossiliferous shales of a greatly thickened submember C9 here about 11 m (36 ft) thick in contrast to 3.6 to 4 m (11-14 ft) at Stop 4. The upper portion of this unit, visible at the base of the cut, consists of nearly barren, silty shale with one or two thin calcisiltite bands. The fossil-rich submember D is not recognizable at this locality; its position appears to be occupied by a section of interbedded shales and thin (5-10 cm) calcisiltite bands. Four or five prominent ledge-forming dolomitic calcisiltites occur near the center of the outcrop, apparently representing the lateral equivalent of "bryozoa beds" (submember E). These bands exhibit sedimentary structures including hummocky cross lamination, rippled upper surfaces, and sharp, scoured basal surfaces, suggestive of current deposition of fine carbonate silt. The beds are interpreted as layers derived from winnowing of bryozoan-crinoid shoals which existed to the north (e.g. at the northern of Niagara Gorge). Ripple- and cross-bed orientation suggest southerly current transport of sediments.
Immediately overlying the highest dolomitic band are 1 or 2 thin layers of coarse, rusty weathering biosparite containing an abundance of brachiopods, pelmatozoans and some bryozoan debris, interbedded with slightly fossiliferous shales. These are essentially the only fossil-rich beds in the entire outcrop and they appear to represent a southern vestige of the topmost bed of unit E in the north. Two km to the north the Whirlpool State Park these bands thicken into a 10-20 cm thick interval of fossil debris and the underlying dolomitic calcisiltites interfinger with typical bryozoan-bearing beds indicating a clearcut transition from typical biosparites of unit E, to the dolostones seen at this locality. The upper bed of fossil debris is followed abruptly by barren shales of the Burleigh Hill Member, which closely resemble those of unit C. The Burleigh Hill is about 6 m thick and displays a sharp, probably erosional, upper contact with the DeCew Dolostone.
This sparsely fossiliferous section stands in striking contrast to sections just a few miles north. It suggests the presence of a fairly abrupt, southward dipping paleoslope.

STOP 6. Ontario Hydro Access Road Cut.
Pass circle at Maid of the Mist information building. Pull off bus along the river road here and park. Proceed on foot to access road for Ontario Hydro Niagara Plant, and Maid of the Mist launch area. Note excellent exposures of Lockport Group beginning at the top of the roadcut with Eramosa Dolostone, followed below by the vuggy stromatolitic and stromatoporoid-bearing Goat Island Dolostone and the dolomitic crinoidal limestone of the Gasport Formation; this unit, in turn, is underlain by buff-weathering, sugary-textured, DeCew Dolostone, exhibiting prominent soft sediment deformation ("enterolithic structure"). The access road forks into two branches, one leading to the straight ahead to the Ontario Hydro Plant, and the other, left hand fork leads to the Maid of the Mist launch area. Near the fork are exposures of the upper part of the Rochester Shale.
This roadcut provides one of the southernmost exposures of the Rochester Shale in New York State. Here the upper contact of the formation is well exposed, just north of the fork in the road. The buff-weathering enterolithic DeCew Dolostone rests with sharp, wavy, and apparently channeled contact on the barren shales of the middle Burleigh Hill Member. No transitional interval is observed at this locality and the Burleigh Hill is only about 4.7 m thick. This situation contrasts with the gradational upper contact of the Rochester Shale observed in most western New York localities. It suggests that the upper Burleigh Hill beds have been removed, possibly by downslope erosional truncation, prior to DeCew carbonate silt deposition. The prominent enterolithic structure of the DeCew Dolostone has long been noted and may have resulted from downslope slumping of rapidly deposited carbonate sediments.

B2: GLACIAL AND ENGINEERING GEOLOGY ASPECTS OF THE NIAGARA FALLS AND GORGE
Parker E. Calkin
Buffalo, NY 14214
Thomas A. Wilkinson
U.S. Army Corps of Engineers
Buffalo District, Buffalo, NY 14207
The Niagara River separating Canada and the United States (Frontispiece II) is unusual as compared to other rivers. for its (a) short length and (b) discharge stability due to the immense storage capacity of its drainage basin. It is largely supplied by the excess discharge brought into Lake Erie from Lakes Superior, Michigan and Huron. In addition to their stabilizing effect, the Great Lakes trap most of the basin sediment so that the river is essentially sediment free (Philbrick, 1970). From its mouth at the north end of Lake Erie at 174.4 m (572 ft) the Niagara descends 23.3 m (73 ft) to the brink of the Falls, drops vertically 51 m (167 ft) (Fig. I), and then descends another 22.6 m (74 ft) in gorge to Lake Ontario at 753m (246 ft). The mean natural flow is about 5,721 m3 sec-l (202,000 ft3 sec-1), and can be increased temporarily by as much as 50 percent due to water surface set up during storms along Lake Erie. However, it is otherwise very stable. Since about 1905, the flow over the Falls itself has been markedly limited by water diversion for hydroelectric power generation. Presently it carries 50 percent of the river's natural flow or about 2,800 m3 sec-l (1003000 ft3 sec-1) during tourist hours and only about 25 percent (1,400 m3 sec-l /50,000 ft3 sec-1) at other times. About 92 percent of undiverted flow passes over the Horseshoe Falls, 8 percent over the American Falls, and this percentage may have been the average even under precontrol discharges (American Falls International Board, 1974).
The differences in elevation that cause the Falls is related to the presence of the Niagara cuesta (escarpment) that divides the Erie and Ontario basins (Frontispiece I and II). The canyon (gorge) of the Niagara has been cut southward from this escarpment into a section of jointed, gently south-dipping sedimentary rocks capped by the tough Lockport dolostone. The stratigraphy is considered in detail in a subsequent section of this paper and in Brett (1982, this volume).
The modern Niagara River was initiated as a multi-outlet river-lake system following the last retreat of the Last Wisconsin ice sheet; the cutting of its deep incised gorge through time is related in various degrees to the changes in drainage controlled by this ice retreat. The ancestral development culminating with a more detailed chronology for development of the Upper Great Gorge is the initial subject of this paper. The second part considers details of the geology in the present area of the Falls and the geologic processes that control stability as well as retreat of the Falls and Gorge as they are revealed in the context of major engineering projects undertaken principally along the east (American) side of the Niagara Gorge. A third section considers the future of the Falls.

B2: GLACIAL AND ENGINEERING GEOLOGY ASPECTS OF THE NIAGARA FALLS AND GORGE

Travel over glacial Lake Warren plain
Travel over glacial Lake Warren plain with red clay colored by Queenston Shale. We are also at south margin of Lake Tonawanda plain.

Subdued topography
Subdued topography due to subaqueous deposition in Lake Warren and washing by initial stages of Niagara River System.

Note spray of Falls at Left.

Structures at left house gates for water intakes to Robert Moses Niagara Power Plant.

Niagara Falls Sewage Treatment Plant on right
Pass Carborundum Company and Niagara Falls Sewage Treatment Plant on right, Grass Island Pool and control structure (mostly on Canadian side) on distant left.

STOP 1. Goat Island
The Horseshoe Falls is seen between emerged bedrock terraces of the ancestral river. The Niagara Falls Moraine forms the bluff behind the Falls on the Canadian Side. The bedrock slopes which form the Horseshoe and American Rapids are connected beneath Goat Island, at this site, and represent the eastern bank of Spencer's (1907) "pre-glacial Falls-Chippewa Valley." This was believed to trend southward from headwater 2 Km (1.2 mi) to the north (near head of north-trending St. Davids Gorge). Figure 3a shows the surficial deposits on Goat Island.
The stratigraphy, structure, talus accumulation, and general location of previous rockfalls at the American Falls will be observed at this stop.

STOP 2. Schoellkopf Geological Museum
This is the site of the massive rockfall that destroyed the Schoellkopf Powerhouse Stations 3B and 3C and damaged 3A on June 7, 1956. This area of failure will be observed and described.

STOP 3. Whirlpool Park
Descend from the parking lot a series of bedrock or gravel river terraces to Gorge margin and view of Whirlpool. The Whirlpool formed soon after 9800 yr 13P when the retreating Falls intersected the buried St. Davids Gorge (see Figs. 1, 2, 3b). Known since the time of James Holland and Charles Lyell, this gorge is as deep and nearly as wide as the Upper Great Gorge (Hobson and Terasmae, 1969), and extends northward across the Escarpment at the community of St. Davids, Ontario, to the mouth of the Niagara at Niagara-On-The-Lake. Taylor (1933) showed that it probably reached as far south (upstream) as the Railroad Bridge where till was encountered in the Gorge bottom and probably up to the head of the Whirlpool Rapids section (Fig. 1). The age and nature of the drift fill (Fig. 2) suggest cutting occurred during or more probably before Middle Wisconsin time under nonglacial conditions when river discharges and base-level conditions were similar to those of the present.
The Gorge walls expose Lockport Dolostone down through Lower Silurian, Whirlpool Sandstone (type area).

STOP 4. Devils Hole
This is a plunge pool formed by drainage from Lake Tonawanda via a shallow channel east of the main Niagara channel (Fig. 1). The cave has enlarged through solution localized along a master joint. This site is a good one for viewing the stratigraphy and structure of the Lockport Formation.
Bloody Run, the stream now occupying the lower end of this channel, is named after an Indian massacre of settlers which is reported to have occurred here in 1763.

STOP 5. Robert Moses Niagara Power Plant
A brief stop at this plant will be made to observe the limited exposures of rock excavation surface. The Power Vista itself displays models of Niagara Falls and Gorge, the power generating plant setup and in addition, views of the Gorge stratigraphy. Elevator service to the base of the Power Plant Access Road (traversing good exposures of the Queenston through the Lockport formations) may be obtained for geology field trips with special permission.

Cross Barre Moraine at crest of Niagara Escarpment
Cross Barre Moraine at crest of Niagara Escarpment with view of lake Iroquois plain to north.
Descend Escarpment; note meandering lower Niagara River with drop of less than 1 m in 6 mi (9 Km) distance to lake Ontario.

Rt. 104 E here follows crest of wave-cut bluff
Rt. 104 E here follows crest of wave-cut bluff of lake Iroquois with thin lacustrine silts on till. Niagara Escarpment at right.

Rt. 104 starts to follow crest of Lake Iroquois beach ridge.

A second ridge occurs to North
A second ridge occurs to North (North Ridge spit) probably derived from the lockport spillway to the east.

Enter bedrock embayment of lockport spillway system for lake Tonawanda.

Turn left up Escarpment on East Jackson St.
The lockport Wastewater Treatment Plant on right is lockport Gulf site of Calkin and Brett (1978) and Miller and Morgan (1982). Subsurface exposure of the lockport Gulf site have revealed the following stratigraphy:
Top 0.5 m | Fill
2.5 m | Massive silty clay (post glacial)
2.0 m | Gray organic silt, clay, and marl with pollen dominated by spruce; basal wood date of 10,920+ 160 yr BP (1-5841)
3.5 m | Laminated red and gray sand, silt, and clay (Lake Iroquois?)
Base 9.0 m | Red clayey sand and gravel interpreted to be till (only in borings)
East Jackson St. follows one of the three major spillway channels at Lockport.

Kame deposits are related to Albion-Rochester Moraine.

STOP 6. Outwater Park, Lockport
View northward from Lockport Escarpment of Lake Iroquois plain and Lake Ontario (if clear) 11 mi. distant. The Lockport Gulf (W. Jackson St.) spillway circles just below. Good exposures of the bedrock surface and northeast-southwest oriented striations occur in the park dump area to the west of the water tank.

Cross High Street on crest of Barre Moraine ridge.

Another of four Barre Moraine ridges
Cross Summit Street at light, another of four Barre Moraine ridges mapped by Gilbert (Kindle and Taylor, 1913).

You are in middle of the former River -- Lake Tonawanda plain.
You are in middle of the former River -- Lake Tonawanda plain. A few low NE-SW-oriented drumlins can be seen to the northeast.

B3: QUATERNARY STRATIGRAPHY AND BLUFF EROSION WESTERN LAKE ONTARIO, NEW YORK
PARKER E. CALKIN Department of Geological Sciences
Buffalo, New York 14226
ERNEST H. MULLER*
Syracuse, New York 13210
THOMAS F. DREXHAGE*
Acres American Inc.
Liberty Bank Building
Buffalo, New York 14202
Wave-steepened bluffs along the south coast of Lake Ontario display the most continuous and some of the most interesting exposures of glacial drift in New York. Study of these bluffs provides detail of local and regional Pleistocene history, as well as insight into mechanisms of glacio-lacustrine sedimentation. In addition, knowledge of the composition, structure and correlation of bluff materials is fundamental to interpretation of rates and modes of coastal recession and sediment contribution to the lake basin. Wave and subaerial erosion of these bluffs has been particularly severe because bedrock comprises a very small part of the bluff sections.
Record, or near-record high lake levels between 1972 and 1978 greatly accelerated bluff recession and provided the stimulus for a Sea Grant study at SUNY Buffalo of more than 400 km (250 mi) of Lake Ontario coast in New York (Drexhage and Calkin, 1981).
In this guide book we focus on 1) the geologic setting, composition and stratigraphy of the bluffs west of Rochester (Fig. 1); 2) the historic rates and distribution of bluff recession and sediment loading to the lake along this same reach of coast; and 3) some of the factors that influence local differences in recession rates.
Much of the data on bluff recession in this report is from the comprehensive study of historic recession along the whole coast in New York (Drexhage and Calkin, 1981), as well as more local studies (Fortune and Calkin, 1981; Brennan and Calkin, in press). A comprehensive account of the Lake Ontario bluff stratigraphy in New York will be published elsewhere (P.E.Calkin and E.H.Muller, in prep.), but preliminary accounts have been presented by Calkin and Brennan (1976) and Calkin and others (1978).
Basic field measurements and sampling for the stratigraphic study were undertaken during the summers of 1974 and 1975 when Lake Ontario levels were, at times, as much as 1.5 ft (0.45 m) above the 1OO-year monthly averages which range from 245 to 246.6 ft (74.68 to 74.86 m), respectively. Bluff sections were measured at least every kilometer. Attempts were made to trace stratigraphic units continuously along the coast. In this guide, the same station numbers are used for location on Figures 5 through 25 and are referred to in the text without figure numbers and usually within parentheses.
* Field trip leaders

B3: QUATERNARY STRATIGRAPHY AND BLUFF EROSION WESTERN LAKE ONTARIO, NEW YORK

STOP 1. Terrapin Point, Goat Island, Niagara Falls.
We will take time only for photographs. See Calkin and Wilkinson (this volume, Stop 1) for details.

STOP 2. Whirlpool State Park.
This again is only a photostop. See Calkin and Wilkinson (this volume, Stop 3) for details.

Cross Barre Moraine at crest of Niagara Escarpment
Cross Barre Moraine at Country Club atop the Niagara Escarpment. View north of Lake Ontario (if clear) across Lake Iroquois plain in foreground below Escarpment.

Descend Escarpment.

Proceed north onto Iroquois lake plain
Pass under Route 104 across wave-formed bluff and strand of Lake Iroquois. Proceed north onto Iroquois lake plain on Route 18.

View Lake Ontario and bluff
View Lake Ontario and bluff at 23 (Fig. 7). Nearshore gradient is about 8.6 m/km; both short and long-term recession average under 30 cm/yr. (Drexhage and Calkin, 1981).

STOP 3. Roosevelt Beach.
Park at boat ramp site enclosed by storm fence and gate. You are 100 m east of Station 34.
The bluff stratigraphy as exposed in 1975 was:
Top 0.5 m | Fill
2.5 m | Massive silty clay (post glacial)
2.0 m | Gray organic silt, clay, and marl with pollen dominated by spruce; basal wood date of 10,920+ 160 yr BP (1-5841)
3.5 m | Laminated red and gray sand, silt, and clay (Lake Iroquois?)
Base 9.0 m | Red clayey sand and gravel interpreted to be till (only in borings)
Approximately 1200 m to the west, the lower compact till is separated from the overlying till by a stone pavement. Gilbert (1898) described a well developed stone pavement exposed in shore bluffs for a half mile east of the mouth of Tuscarora Bay. Marked parallelism of striae on the flat upper surface of 10 of these boulders indicated deposition of the upper till to have been by ice flowing S50W. He interpreted the stone pavement as distinguishing two tills. An alternative explanation recognizes the upper till as a subaqueous allo-till facies; the lower till as lodgement facies representing the same glaciation.
The highest bluff recession rates in Niagara County are measured at Roosevelt Beach (Drexhage and Calkin, 1981). Between 1938 and 1951 the bluff receded at an average rate of 2.1 ft/yr. Prior to 1902, Twelvemile Creek entered Lake Ontario through Tuscarora Bay. In 1902, the receding shore bluffs breached the left bank of Twelvemile Creek. Subsequent sedimentation has built a barrier across the former channel, isolating the mouth of Twelvemile Creek from that of its East Branch and tying the "Island" east of the State Park to the mainland. (See also Brennan, 1979, Fig. 13, Stn. 11, pp 36-37, and Fortune and Calkin, 1981.)

Note elongate, northeast-trending ridge at right.
Note elongate, northeast-trending ridge at right. This is the general trend of ground moraine ridges in this part of the lake plain. Though very subdued, this grain controls orientation of minor drainage lines. In part, at least, it is considered to reflect fluting of underlying bedrock by glacial erosion.

STOP 4. Olcott Bluffs.
Located between Stations 56 and 57 (Fig. 11). This is the eastern edge of a somewhat uneven silt-topped sand plain that stretches along the coast from Olcott and inland at least one mile to a low ridge, 10 to 20 ft. high and correlable with the Carlton Moraine. Ice-contact features have not been recognized in the thick cross-bedded, subaqueous sands, but their occurrence above abnormally thick clay-silt rhythmites and below fine silt suggests ice marginal oscillation. Figure 26 shows the section as measured 1 km to the west. Seeps near base of the stratified drift induce mass wasting which now largely obscures stratigraphic relationships at this site. Queenston bedrock crops out at bases of bluffs on headlands adjoining this stretch of shoreline. Bluff recession less than 30 cm/yr.

STOP 5. Somerset Bluffs.
Located between Stations 60 and 61. In 1974, the wave-eroded bluffs here recorded two tills, a red stony till overlain by purplish-gray silty till. This section is also revealed in borings for the facility. The following section was measured in 1975:
Top | 0.4 m | Lake clay, silty, oxidized
| 0.55 m | Lake silt, yellow; contains convoluted beds and dropstones.
| 1.1 m | Till, interbedded yellow sand, locally gravelly; subaqueous allo-till (?)
| 2.1 m | Till, purple-red, 10% stones, compact. lodgement and subaqueous till.
| 0.5 m | Queenston bedrock

STOP 6. Thirty Mile Point
This is Station 75 (Fig. 16). Bedrock reaches its greatest elevation above lake level in shorebluff of the south coast of Lake Ontario at Thirty Mile Point. Lake silts and sandy silt till overlie some 3 to 4 m of Queenston bedrock.
Of particular interest is the small, fractured bedrock anticline with northwest-southeast trend paralleling the coastline. As described by Gilbert (1899), the crest was broken by a steeply northeasterly dipping fracture, the northeast side displaced upward 2m with overturning of fold axis to the southwest, enclosing till. Although continuing below lake level, the deformation seems to die out downward. Evidence suggests glaciotectonic thrusting by southwesterly moving ice following initial till deposition (Kindle and Taylor, 1913).
Gilbert wrote "Should this description rouse enough interest to induce others to examine the locality, their visits should not be long delayed. This part of the coast is specially exposed to the attack of storm waves and is rapidly beaten back." Eighty years later, however, the exposure appears much as illustrated by Gilbert with apparent bluff recession of no more than 2-3 m in that interval.

Carlton Moraine trending parallel to route.
Note very gently hummocky topography of Carlton Moraine trending parallel to route.

Orchard Creek has been incised deeply into bedrock
Orchard Creek has been incised deeply into bedrock by early postglacial stream erosion. Like other creeks on this south coast of Lake Ontario, its gradient has been diminished and its debouchment into Lake Ontario drowned by postglacial tilting. Shore bluff retreat partly counters the estuary development that tilting has produced.

STOP 7. Brighton Cliff.
Bouldery to sandy supraglacial drift correlated with ridges of the Carlton Moraine 1 to 2 mi south. Underlying weakly bedded till overlies compact till similar to the main till unit of the Niagara River to Rochester reach of the Ontario coastline. The stratigraphy in the bluff is depicted in Figure 27 from Brennan (1979)."At the top of the till, a deformed boulder layer lies on a distinct erosion surface; above the boulder layer pebbly sand grades upwards to fine sand and silt". (Brennan, 1979, p. 47). Pods of till within the sand and small-scale normal faults further suggest ice contact deposition. Features like the fault in Figure 27b may represent deformation during the Carlton glaciation.

Carlton Moraine
Proceed through type area of Carlton Moraine at the railroad tracks.

Cross Lake Iroquois beach ridge

Pass over Albion Moraine

Cross esker

Note esker ridge angling obliquely toward road.

Bear right at fork onto Kams Road and along esker ridge.

Turn right onto Maple Street across the Burma Woods kames.

STOP 8. Burma Woods Esker/Kame Complex.
The extensive area of glacier disintegration topography traversed for the past three miles developed during wastage of the glacier front from the Barre Moraine, about .5 miles south of this point. The stagnating ice margin apparently fronted on Lake Lundy (Lake Dana (?)) at a stage when it was too shallow to float large ice bergs. The Burma Woods Esker can be readily traced for 4 mi (6.4 km ) and conceivably extends all the way to the Albion Moraine, making it perhaps the longest esker in western New York. It consists of a number of discrete segments, the last to be deposited being at the north end. One of the segments terminates in a kame delta at about 735 ft. suggesting the level of Lake Lundy into which it was deposited. Distinct deltaic foreset bedding can be observed in this pit. See Figure 28 for location.

This is the frontal ridge of the Barre Moraine.
Turn left onto Hemlock Ridge Road. This is the frontal ridge of the Barre Moraine. Proceed east through West Barre on Root Road (continuation of Hemlock Ridge Road) and cross lake flats with several closely spaced drumlin ridges oriented northeast-southwest.

Cross eastern end of Oak Orchard Creek headwaters
Cross eastern end of Oak Orchard Creek headwaters and surrounding swamp, as well as several southwest-oriented drumlins.

Elba -- the "onion capital of N.Y.S."

Cross Onondaga Escarpment
Cross Onondaga Escarpment and rise onto Onondaga Bench. The Batavia Moraine crosses Route 98 at top of the scarp.

Gravel kame topography
Gravel kame topography correlated with the Buffalo Moraine trends northwest away from Thruway on right.

Cross through partly quarried-out kames
Cross through partly quarried-out kames related to the Buffalo Moraine

Pass gravel pits in thick gravel
Pass gravel pits in thick gravel associated with Buffalo Moraine (Calkin, this volume, Figure 2).

Quarry on right next mile in Onondaga Limestone

Cross Onondaga Limestone Escarpment and under Route 5 (Main Street).

B4: SEDIMENTOLOGIC AND GEOMORPHIC PROCESSES AND EVOLUTION OF BUTTERMILK VALLEY, WEST VALLEY, NY
JON C. BOOTHROYD
University of Rhode Island.
Kingston, RI 02881
BARRY S. TIMSON
Earth Surface Research, Inc.
114 State St. Augusta, ME 04330
LORIE A. DUNNE
Albany, NY 12230
The purpose of this trip is to investigate the sedimentologic and geomorphic processes active in a small non-glacial gravel stream and on adjacent valley walls and tributaries. The work that led to this field trip is part of a larger geologic and hydrologic study by the New York State Geological Survey of the low-level nuclear waste disposal site and other use areas of the West Valley Nuclear Service Center. The geomorphic study is being done to determine, as accurately as possible, the denudation rate in the Buttermilk drainage basin, and to estimate rate and magnitude of morphologic changes to the waste-burial site.
Buttermilk Creek, located in southwestern New York (Fig. 1), has a drainage basin area of 78.4 km2 and is a tributary of Cattaraugus Creek. Figure 2 shows detail of that part of the drainage basin adjacent to the West Valley Nuclear Service Center (WVNSC).
GENERAL GEOLOGY
Surficial Geology
The area of interest is in the Ashford Hollow and West Valley 7 1/2 minute quadrangles. The regional surficial geology has been mapped by Muller (1977) and discussed by Coates (1976). Wisconsinan glacial features and later Holocene modifications of the 2 quadrangles have been mapped in great detail by Lafleur (1979) and discussed by him on the 1980 Friends of the Pleistocene field trip (Lafleur, 1980).
An upper plateau containing the waste-burial trenches, is underlain by till capped in places by a thin layer of fluvial gravel that marks the original fluvial surface immediately following the late Woodfordian deglaciation. Movement of groundwater in the vicinity of the waste-burial trenches has been investigated by Prudic (1979) and Prudic and Randall (1979). Mapping by Boothroyd et al. (1979, 1981) has further refined Lafleur's units in the vicinity of the WVNSC. There are eight till units, identified by age and present steepness of slope, and ten fluvial/alluvial fan systems ranging from the presently-active bar and channel system to late Woodfordian proglacial channels.

B4: SEDIMENTOLOGIC AND GEOMORPHIC PROCESSES AND EVOLUTION OF BUTTERMILK VALLEY, WEST VALLEY, NY

West Valley Nuclear Service Center (WVNSC) entrance.

STOP 1. Overview of the West Valley Nuclear Service Center.
The buildings housing the nuclear fuel reprocessing facility are to the left, waste-burial trenches are to the right. The land and buildings inside the high-security fence are owned presently by the U.S. Dept. of Energy and operated for them by the Westinghouse Corp. Westinghouse is carrying out the West Valley Demonstration Project, a program to solidify the high-level liquid waste stored on site, for later isolation in a still-to-be chosen facility. The NRC-licensed intermediate-level burial trench (left) is also operated by Westinghouse; the low-level trenches (right) are owned by the NYSERDA and are no longer accepting waste material.
The buildings are situated on an early Holocene alluvial fan; the waste-burial trenches are excavated in late Woodfordian Lavery till (Lafleur, 1979). The plateau containing the trenches marks the surface elevation of Buttermilk valley in early post-glacial time. The plateau beyond the trenches is covered by a thin veneer of fluvial gravel deposited in the ancestral late-glacial to early post-glacial Buttermilk Creek. Initial incision and downcutting began sometime before 9900 BP (Fig. 8), and continues to the present. The field trip discussion will focus on the manner and rate of erosion that will, in time, remove the plateau, and with it the waste-burial trenches.

Look for south reservoir in valley on the left.

New York State Plutonium Storage Facility.
End of paved road. STOP. Obtain prior permission to proceed on dirt road. CAUTION. This road is rough and steep. Trucks and/or 4 WD vehicles needed in wet weather. Go downhill and cross B & 0 RR tracks.

STOP 2. Assembly point.
Park vehicles so they do not block the B & 0 work road or access up and down the hill. Old Buttermilk Hill Rd. continues to Buttermilk Creek (100 m), the bridge has been removed. The surveyed section (Buttermilk-Bond reach) begins at the former site of the bridge and extends downstream to the north. Reservoir slug discharge enters from the west just below the bridge site.

Active channel of Buttermilk is undercutting railroad embankment.
View of bar complexes and low terraces.

STOP 3. Gravel-bar complexes, valley-wall landslides, etc.
Gravel-bar complexes, valley-wall landslides and alluvial fans, and Buttermilk fluvial terraces. The tributary stream enters Buttermilk Creek at bar complex 6, opposite the BC-6 landslide (Fig. 7). Extending 250 m upstream, to your left or south, is the BC 4-6 bar complex (Fig. 5). Just upstream of BC 4-6 is the BC-3 alluvial fan, situated on the west wall of the valley (Fig. 6). Fluvial terraces at several levels are preserved on the east side of the valley at the BC-6 tributary and on the west side adjacent to the BC-3 alluvial fan (Fig. 8). We shall discuss each of these features in turn, including gravel movement on the bars (Fig. 12). Please take care not to disturb any of the painted clasts.

B5: DEVONIAN BLACK SHALES OF WESTERN NEW YORK
DOUGLAS G. PATCHEN
KATHARINE LEE AVARY
West Virginia Geological Survey
Morgantown, WV 26507
The road log that follows is essentially a condensed version of the final day of a 5-day trip through the Middle and Upper Devonian clastics of central and western New York (Patchen and Dugolinsky, 1979). That particular trip was organized to give various contractors in DOE's Eastern Gas Shales Project (EGSP) the opportunity to examine, in the field, stratigraphic relations and facies changes hidden deep in the subsurface in the central Appalachian basin. The stops on the fifth day were designed to simulate a 2,200 to 2,500 foot stratigraphic section of "Devonian shale" in a typical "Brown Shale" gas well in West Virginia, Kentucky, or Ohio. The stops on this trip will enable us to visualize what the lowest 1,000-1,100 feet of section in such a well would look like. The main difference will be that the Dunkirk Shale, which is only 40-50 feet thick in this area, thickens westward and merges with the basal black shale of the Huron Shale. In southwestern West Virginia this black shale ranges from 300-400 feet in thickness and serves as both source bed and reservoir in more than 30 gas fields. More recently, prolific oil wells with initial potentials (IP's) ranging from 50 to 1,000 barrels per day have been drilled to this and other shales in the Devonian section in several counties along the Ohio River (Fig. 1). Thus, even though the EGSP is now defunct, interest in the Devonian Shales, both in the surface and subsurface, remains high.
When we agreed, at a rather late date, to organize this trip, we secured from Art VanTyne a promise to submit a companion article for the guidebook discussing surface to subsurface correlations and gas production from Devonian shales in New York. Furthermore, Wallace de Witt informed us that he would present a paper on Devonian shale stratigraphy at the Eastern Section meeting of the American Association of Petroleum Geologists that immediately precedes the NYSGA field trips. Therefore, we refer the readers to their articles and will present only the barest of stratigraphic summaries herein.

B5: DEVONIAN BLACK SHALES OF WESTERN NEW YORK

Exposures of Onondaga Limestone
Exposures of Onondaga Limestone along both sides of the highway. The black Marcellus Shale that overlies the Onondaga cannot be readily observed in the Buffalo area due to the relatively flat topography near Lake Erie.

Rhinestreet Shale with large concretions.
Town of Hamburg water tower. Good exposure of black Rhinestreet Shale with large concretions.

Exposures of the Ledyard and Wanakah Shales
Entrance for Hamburg Park. Exposures of the Ledyard and Wanakah Shales of the Ludlowville Formation can be observed near lake level in the park but not from the highway. Stop 1 of Tesmer (1966); stop 47 of Patchen and Dugolinsky (1979).

STOP 1. Eighteenmile Creek Gorge
Turn left on South Creek Road; park on right side of road. Walk carefully back along the road and over the bridge.
Upstream from the bridge over the main highway are exposures of the Wanakah Shale, Tichenor Limestone, Windom and Penn Yan Shales, Genundewa Limestone, and a few feet of West River Shale. The black shale near the top of the outcrop, which is weathered a reddish color and displays well-developed fractures, is the base of the Middlesex Shale. Notice the weathered pyrite associated with the base of the Tichenor Limestone, along with the abundant fossils, both characteristic of the Tichenor.
It is possible to walk from the exposures on the beach at the mouth of this stream where the Wanakah and Tichenor are present, upstream past the point and see the Middlesex, Cashaqua and Rhinestreet. Thus, continuous exposures from the Ludlowville Formation of the Upper Hamilton Group, through the Moscow Formation, the Genesee and Sonyea Formations, and into the West Falls Formation are present and all visible, representing a large proportion of Middle and Upper Devonian time.

STOP 2. Rt. 5 Bridge Over Eighteenmile Creek
JCT with Rt. 5. Cross and park on right. Descend gorge under the bridge.
The Wanakah Shale is exposed in the stream bed and may be under water, depending on water level. This is followed upward by one or two feet of Tichenor Limestone, about ten feet of Windom and Penn Yan Shale, some thin Genundewa Limestone, about 3 feet of West River Shale, a few feet of dark, platy Middlesex Shale, and the lower few feet of Cashaqua Shale which cap the section. The entire section is perhaps 35 to 40 feet thick and all is accessible.

Railroad Bridge.
Short walk along path to left before RR bridge offers a view of upper Cashaqua and lower Rhinestreet (Stop 3 of Tesmer, 1966).

Excellent, thick exposures of black Rhinestreet Shale
Drive slowly across bridge in right lane; turn around in parking area to right and drive back. Observe excellent, thick exposures of black Rhinestreet Shale in stream banks.

STOP 3: Town Of Evans Nature Park
Exposures of the Rhinestreet may be seen along the road and adjacent to the parking lot by the pedestrian bridge. The base of the Rhinestreet is exposed farther downstream but not here. The shale here is the typical dark, platy shale characteristic of the Rhinestreet, with reddish weathering in places and concretions being very common, although not as evident at this locality as they are in Rhinestreet exposures along I-90 southeast of Hamburg.

Entrance to home of Piarist Fathers
Entrance to home of Piarist Fathers, Stop 48 of Patchen and Dugolinsky (1979); Stop 2 of Tesmer (1966). Exposures of the Wanakah Shale, Tichenor Limestone and Windom Shale are present along the beach. If anyone is interested in examining this site, permission should be obtained from the residents. Also, access to the beach is by way of an old metal stairway. Extreme caution should be used.

Windom Shale to Middlesex Shale interval
Gibraltar on the Lake (PRIVATE ROAD). Stop 52 of Patchen and Dugolinsky (1979). The Windom Shale to Middlesex Shale interval is exposed along the beach.

Evangola State Park
Turn left at entrance to Evangola State Park. This was Stop 53 of Patchen and Dugolinsky (1979); Stop 5 of Tesmer (1966).

STOP 4: Walnut Creek In Town Of Silver Creek
Park along Parkway near fire hydrant. Walk through small lot to edge of Walnut Creek. Descend into creek bed. Observe Pipe Creek Shale above Angola Shale. Wade under bridge to 60 ft. exposure of Hanover. Dunkirk Shale is exposed 2 miles upstream.
The contacts of the Pipe Creek Shale with the underlying Angola Shale and the overlying Hanover Shale are exposed in the stream bed of Walnut Creek in the Town of Silver Creek. The top 5 feet or so of the Angola is all that is clearly exposed, but the entire Pipe Creek and the lower 60 feet of Hanover are accessible, although wading boots are suggested. Lithologies in the Hanover range from green-gray, thinly bedded shales to silty beds which are more prominent due to higher resistance to weathering.

STOP 5. Point Gratiot, Dunkirk
Turn right (just after paved entrance to power station) into unpaved parking area and park.
The base of the Dunkirk is well exposed on the beach just south of the power plant. The distinct transition zone between the Hanover and the Dunkirk at, and just beneath (but visible in clear water), the water at normal lake level. The greenish-gray beds of the Hanover and the black beds of the Dunkirk are separated by two black and two greenish-gray transition beds. A small exposure may be seen, particularly if the water is calm, by tracing the lighter colored units along the beach and noticing a slight northward dip in this location.
Feeding trails and carbonized plant fragments may be seen on the tops of the beds within the transition zone. Pyrite nodules are common. A freshly broken surface of Dunkirk Shale provides a strong petroleum odor.

New gas wells in vineyards to east.
Along the route notice new gas wells in vineyards to east. These are in the Medina sands (Lower Silurian).

About 55 feet of Dunkirk Shale are exposed in the gully under the bridge.
Cross bridge adjacent to an old bridge on a parallel route to the right (east). This was Stop 55 of Patchen and Dugolinsky (1979). About 55 feet of Dunkirk Shale are exposed in the gully under the bridge. The transitional zone between the Hanover and Dunkirk can be observed in the stream bed.

Observe excellent Hanover-Dunkirk contact on the right.

Cross gorge with fairly poor exposure.

Cross gorge with a good section exposed.

Excellent Rhinestreet exposure
Excellent Rhinestreet exposure along both sides of the thruway near the town of Hamburg water tower. The large concretions are characteristic of the Rhinestreet in this area.

Rhinestreet-Cashaqua contact in the ditch to the east.

State University College
of Arts and Science

1:SEISMOLOGY, TECTONICS AND ENGINEERING GEOLOGY IN THE ST. LAWRENCE VALLEY AND NORTHWEST ADIRONDACKS
Frank A. Revetta, Department of Geology
State University College of Arts and Science
Potsdam, New York 13676
William P. Harrison, Department of Civil and Environmental Engineering
Clarkson College of Technology
Noel Barstow and Ellyn Schlesinger-Miller
Lamont-Doherty Geological Observatory of Columbia University
Palisades, New York 10964
The purpose of this field trip is to develop an understanding of the seismicity and tectonics of the St. Lawrence Valley in Northern New York and the engineering geologic aspects of the St. Lawrence Seaway and Power Authority of New York State. Six stops will be made - one in the vicinity of Norfolk, New York and five in the Massena area. The locations of all stops are shown on Figure 1.
STOP 1 will be near Norfolk, New York (Figure 1) to observe a seismic field station which detects earthquakes that are recorded at Potsdam State College. STOP 2 is at the St. Lawrence Seaway Development Corporation office in Massena, New York (Figure 1) where engineers will discuss the St. Lawrence Seaway System. STOP 3 will be at Massena Center, New York, the epicentral region of the Massena-Cornwall earthquake. At this stop residents who experienced this earthquake will share their recollections of the earthquake with you. STOP 4 will be at the Eisenhower Lock where the engineering aspects of the lock will be discussed. Lunch will be eaten here, and hopefully a ship may be observed passing through the lock. At STOP 5 we will view the Long Sault Dam and observe seismic equipment in operation to detect local earthquakes. STOP 6 will be at Moses-Saunders Power Dam where engineers will discuss the operations and construction of the dam. At this stop there are a number of exhibits and a 30-minute film on the construction of the St. Lawrence Power Project.
All participants will meet in Room 120, Timerman Hall at 8:00 A.M., September 24 to hear a slide-talk on the seismology, tectonics and engineering geology of the St. Lawrence Valley. Frank Revetta will speak on the Massena-Cornwall earthquake of September 5, 1944. Ellyn Schlesinger-Miller and Noel Barstow will discuss the seismology and tectonics of the. Northern New York area. Bill Harrison will discuss the engineering geology of the St. Lawrence Seaway and Power Authority of the St. Lawrence River Valley. Slides will be shown of the stops made on the field trip. Participants will then proceed into the hallway for a brief discussion of the seismicity of Northern New York and the Lamont-Doherty Seismic Network.

Room 120 Timerman Hall
Slide-talk on seismology, tectonics and engineering geology of St. Lawrence Valley

STOP 1. Seismic Field Station
This stop will enable you to observe the operation of a seismic field station (Figure 2). The seismic equipment is contained. in two 55 gallon steel drums. In one drum is a short period (1 second) horizontal geophone, preamplifier-voltage controlled oscillator,and an FM radio transmitter. The geophone is mounted on bedrock which, in this case, is the Ogdensburg dolomite. The geophone detects the ground motion and its voltage output drives the high-gain preamplifier. The amplifier drives a voltage controlled oscillator which is frequency modulated by the geophone signal. This seismic modulated tone is transmitted a distance of 10 miles via an FM transmitter and a high gain directional antenna to Timerman Hall at Potsdam State College. In the second drum are five McGraw Edison 1000 Ampere hour air cells which provide the power for the amplifier, VCO, and radio transmitter for one year.
At the receiver end is another high-gain directional antenna and an FM receiver. The signal, together with the FM carrier wave, is picked up by the receiver and passed into a discriminator where the carrier wave is removed. The signal then passes into the amplifier and into the heliocorder for recording.
2011: Location comes from lat/long of old seismic stations, LDGO website. OHM

STOP 2. St. Lawrence Seaway Development Corporation Operational Building
This stop is at the St. Lawrence Seaway Development Corporation's Administration Building at Massena, New York. At this stop engineers will discuss the construction and operation of the St. Lawrence Seaway. An explanation will be given of a wall display which depicts approximately 2300 miles of waterway from the headwaters of the Great Lakes to the Atlantic Ocean. You will also have the opportunity to view a model of the St. Lawrence Seaway and Power Projects, including the locks, Long Sault Dam, Massena Intake and Village of Massena.

STOP 3. Massena Center
Epicenter Of The Massena-Cornwall Earthquake Of September 5, 1944
Massena Center is the epicenter of the Massena-Cornwall earthquake of September 5, 1944 (Figure 3). The epicenter was located from P-phase arrival times and a least square solution and was found to be at 74° 53.9 W longitude and 44° 58.5' N latitude. The depth of focus of the earthquake was estimated to be 20 miles. The magnitude of the earthquake was 5.9 and a maximum intensity of VIII occurred in the vicinity of Massena Center. The total damage was estimated at $2,000,000.
An interesting fact regarding the damage was in the cemeteries. On the Canadian side of the river the tombstones were generally rotated counterclockwise,and on the United States side they were generally rotated clockwise. It appears that this indicates horizontal displacement along a fault line parallel to the river even though geologists report no surface evidence of any major fault in the immediate area. However, the tombstones and chimney damage indicate an origin somewhere between Cornwall and Massena, which is confirmed from the study of seismograms. The cemeteries are the best evidence of the relative violence of the earthquake in different areas, and they furnish the chief line of division in determining the areas of major damage (Figure 3).
At this stop we will observe tombstones that have been rotated and translated by the Massena-Cornwall earthquake. Also, two Massena Center residents, Messrs. Bob Rickard and James Carton, who experienced the earthquake will discuss their recollections of the event.

Massena Epicenter
2011: The coordinates given in the description of STOP 3 plot up here. OHM

STOP 4. Eisenhower Lock, St. Lawrence Seaway
This structure enables ships traveling the St. Lawrence River to pass around the Moses-Saunders Power Dam and, along with Snell Lock five miles farther east, lowers the ships through a total of 95 feet of elevation. Both locks have dimensions of 850 feet by 80 feet and are of concrete construction. The locks are huge bathtubs, in a sense, with openings along the sides into a passageway (about 13' wide by 15' high) on each side which slopes to the upstream end of the lock. When a ship comes down the St. Lawrence River and through the canal to the lock, the lower lock gates are closed, and the water is at the upper canal elevation. The ship moves slowly into the "bathtub," the upstream gates are closed, and then the water is let out of the locks through the openings in their sides, down the passageway on either side and discharged below the lock. A system of baffles on the downstream end prevents excessive turbulence.
When a ship comes upstream to the lock, the upper gates are closed and the water level is at the same elevation as the water surface downstream from the lock. The ship moves into the lock, the lower gates are closed, and water is introduced into the side passageways from the upstream end of the locks flowing into the lock through the side openings, thus filling the lock and raising the ship to the elevation of the canal on the upstream side. Then the upper gates are opened and the ship moves out of the lock upstream. Recently, some deterioration of the lock concrete has been observed, and an extensive study has been made by the Corps of Engineers, which is resulting in appropriate remedial measures.
At this stop we will visit the Eisenhower Lock Vessel Traffic Control Center to view its functions. Hopefully, we will see a ship pass through the lock. Lunch will be eaten at this stop and a concession stand is available.

STOP 5. Long Sault Dam
The Long Sault Dam is located just below the foot of Long Sault Island, crossing both the main channel of the St. Lawrence River and the smaller channel south of Long Sault Island. It is located four miles north of the Village of Massena, New York and 6.5 miles west of Cornwall, Ontario, Canada (Figure 4). The Long Sault dam serves as a control for the St. Lawrence River, developing approximately 82 feet of drop through the Long Sault Rapids. It is a concrete gravity structure having a maximum height of about 132 feet above foundation. The foundation of the dam is on bedrock (Ogdensburg Dolostone) and the dam is relatively noise free, therefore it is an ideal location for the installation of earthquake detection equipment.
This stop will enable you to observe some seismic equipment installed in the dam by the Lamont-Doherty Geological Observatory and the State University of New York at Binghamton. The dam is an ideal place for the installation of seismic equipment because it is coupled well to the bedrock of the area and is a quiet place. Three instruments may be observed on the lowest level of the dam: a short-period vertical seismometer, strong motion accelerograph (SMA) and a digital cassette accelerograph. The vertical seismometer and the strong motion accelerograph are part of the Lamont-Doherty Seismic Network and the digital event recorder is operated by SUNY at Binghamton.
The short period (1 second) vertical seismometer responds to the ground motion produced by an earthquake. The seismometer drives a high-gain amplifier. The amplifier drives a voltage controlled oscillator (VCO) which is frequency modulated by the seismometer signal. This frequency modulated audio tone is then inserted into a telephone line for transmission to Lamont-Doherty Geological Observatory. At the L.D.G.O. at Palisades, New York the various tones are distributed to the magnetic tape recorder and to appropriate discriminators. The discriminators separate the seismic data from the telephone line carriers. The data is transferred to develocorders and/or helicorders.
The strong motion accelerograph (SMA) was installed by the Lamont-Doherty Geological Observatory. This instrument contains three accelerometers that record on film the vertical and horizontal accelerations produced by a strong earthquake. The instrument remains in a standby condition until an earthquake triggers it. The "P" wave triggers the instrument which operates till the earthquake is recorded. The. SMA can record a single earthquake or a sequence of earthquakes and aftershocks. The event
indicator shows when an earthquake has been recorded. Before an event it is black, after the event, it is white.
The reason for recording such motions comes from two widely different scientific needs. Such measurements are necessary within man-made structures for engineers to develop structural design criteria in earthquake engineering. There is very little information about the accelerations produced by earthquakes in the eastern United States. Secondly, seismologists studying the details of the earthquake source for information on dimensions, stress drops and time histories of the rupture process need measurements in the near-field of larger earthquakes.
The third instrument is a digital cassette seismograph which belongs to Francis Wu, SUNY at Binghamton, New York. This instrument is triggered by the "P" wave and records the event on cassette tape. A portable playback-plotter accompanies the instrument to provide playback for set-up, testing, maintenance and analysis. The seismic data can be translated from cassettes to any IBM compatible tape and can provide a wide variety of seismological analysis.

STOP 6 Moses-Saunders Power Dam
The location map is shown in Figure 4. This dam provides approximately 912,000 kilowatts of power. The dam has a head of 81 feet, and behind it is Lake St. Lawrence, with its fine marina and Barnhart Island Beach.
A thirty minute film will be shown in the auditorium at the dam, which will illustrate the methods and problems of construction.
A tour of the dam will be made, and from the top of the building Lake St. Lawrence can be clearly seen, with some of the zoned and rip-rapped dikes bounding it composed of compacted glacial till with dry densities on the order of 140 pcf (concrete is 150 pcf).

2: GEOLOGIC TRAVERSE FROM POTSDAM TO THE THOUSAND ISLANDS
Bradford B. VanDiver, S.U.N.Y. Potsdam
The Lowlands Adirondacks, or northwestern part of the Adirondack Mountains Province, contains a record of extremely ancient seas that predate the Grenville Orogeny by hundreds of millions of years, and in which limestones, various detrital sediments, and volcanic materials were deposited. The orogeny, now dated at 1100 m.y. in the Adirondacks, produced severe metamorphism, intense deformation, igneous activity, and a mountain range of Himalayan scale extending for thousands of miles along the eastern side of North America as it existed then. These mountains are referred to as the Ancestral Adirondacks. The Grenville-age rocks
we see today, in the Adirondacks, the Thousand Islands, and in the Grenville Province of Canada, are but remnants of the core of that great mountain range, where orogenic processes were most severe (Fig. lA). There ensued a period of erosion that lasted approximately 600 million years and left a landscape of low relief with karsts developed in the marbles. Flooding by shallow seas that advanced from the east, set the stage for deposition of shelf sediments in late-Cambrian Potsdam time, that continued until the beginning of the Taconic Orogeny in late Ordovician time. This once continuous cover of sedimentary rocks has been largely removed from the Adirondacks and Frontenac Arch in the last few million years by erosion accompanying the still-continuing rapid uplift of those regions (Figs. lB, 2) (Isachsen, 1975).
The principal purpose of this field trip is to examine the Precambrian and lower Paleozoic rocks exposed in a traverse from Potsdam to Alexandria Bay, with special regard for the nature bf the unconformity itself. The trip will be highlighted at midday by a boat trip through the lovely Thousand Islands. The route and stops are shown on Figure 3.

2: GEOLOGIC TRAVERSE FROM POTSDAM TO THE THOUSAND ISLANDS

Dark, migmatitic gneiss
Railroad underpass. Exposures of dark, migmatitic gneiss with pink granitic veining.

Small marble cut
Small marble cut, right, with whitish banded marble below and marble thinly interleaved with rusty calc-silicate rock above. Folding here reflects the ductility contrast between these two rock types that is characteristic of the Adirondack region in general. Flow banding in the marble displays a remarkable fluidity, whereas the calc-silicate, though also intensely folded has been extensively ruptured and displaced. The result is a chaotic "marble stew," which resembles what might be seen if strips of crisp fried bacon were swirled in smooth peanut butter. More of this will be seen at Stop 1.

Low, long roadcut in dark greenish-gray calc-silicate rock
Low, long roadcut in dark greenish-gray calc-silicate rock with subordinate marble interlayers, right side of road. Tight recumbent folding.

STOP 1. The Snake Roadcut
This is the now-famous and graffiti-ed Snake Roadcut; the name for which was first published in the guidebook for the 1971 NYSGA meeting at Potsdam (Fig. 4). The cut is a large and outstanding example of the plastic deformation of the Grenville marbles. The "Snake," itself, is a nearly continuous, thin band of microcline-rich rock on the SE cut (left) that has been sinuously infolded with the marble. Despite its thinness and obvious stretching, the Snake has survived nearly unbroken over much of its length. A good example of a refold can be seen at the NE end, where Fl isoclinal folds have been openly folded around an F2 hinge surface. The deformation shown by the Snake is deceptively simple. Greater complexity, perhaps with as many as four separate folding events, can be observed above the Snake on top of the cut (DANGEROUS!), where thin, infolded layers of rusty calc-silicate rock have been exposed in three dimensions by solution of the enclosing and interleaved marble. A less dramatic, but safer, example can be observed at the right end of the opposite cut, near road level.
In the marble adjacent to the Snake, note the dark green, concentric banding of diopside, the product of metamorphic reaction between the dolomitic marble and siliceous parent rock of the Snake. Diopside concentration diminishes rapidly away from the band. Also found in this reaction zone are fine-grained brown sphene, copper-colored phlogopite, yellowish metallic pyrite, green actinolite, black tourmaline, and very minor quartz.
Carl and Van Diver (1971) proposed a subaqueous ashfall origin for the parent material of the Snake, interrupting a shelf limestone sequence. This is suggested both by the composition, and the thin, blanket shape of the layer. Other snakes of similar material, and some of phlogopite may be seen on the opposite cut.

STOP 2. DeKalb Anticline
DeKalb Anticline, located 100 feet from the right side of the road (Fig. 5). This is an overturned anticline in dark brown garnet biotite schist, with interlayered light greenish gray, calc-silicate rocks, altogether a rather unusual rock for the Lowlands Adirondacks. The fold is interrupted near its hinge surface by a two-foot pinkish pegmatite dike. As at the "Snake," the deformation here appears deceptively simple. Contoured point diagrams of minor fold axes prepared by several generations of Structural Geology students at Potsdam, indicate refolding (this is nearly identical to similar diagrams prepared for the Snake). Furthermore, there are a few puzzling S-shaped folds at the right side of the dike that suggest renewed deformation after pegmatite emplacement. Study the texture of the dike from side to side, and see if you can find evidence for this interpretation.
A small cut directly across the highway displays a rusty basaltic (diabasic?) dike that intrudes the biotite schist, with contacts that zig and zag alternately along schistosity and jointing. At the left end, there is a small xenolith of granitic rock incorporated in the basalt. Diabasic dikes like this are common in the Lowlands Adirondacks. They intrude the Grenville-age rocks but not the Potsdam Sandstone, and are considered to be of late Proterozoic to early Cambrian age.

STOP 3. Red-and-White Roadcuts.
This is one of the most dramatic series of new cuts opened by road construction in 1976-77. The first cut on the right (lowest) exposes highly contorted grayish marble in sharp, irregular, discordant, contact with a chaotic mass of friable pinkish to dark brick red sandstone, sandy intraformational breccia, and conglomerate, with assorted inclusions of marble. A wedge-shaped conglomerate dike is located at the top of the marble just to the right of the sedimentary contact.
All of these features undoubtedly result from the infilling of a sinkhole developed in the marble prior to and possibly continuing during marine transgression in Potsdam time. The contact represents an unconformity spanning about 600 million years. Similar features may be observed at numerous places in the northwestern part of the Lowlands Adirondacks, most notably in the Rock Island Road cut 4 miles north of Gouverneur, (Carl and Van Diver, 1971) .
On a regional scale, remnants or outliers of sandy and conglomeratic sediments like this become smaller and less frequent southeastward from the continuous Paleozoic boundary near the St. Lawrence River, and they are largely confined to areas of marble. Because of their lack of fossils, often chaotic nature, and discoloration, their assignment to the Potsdam Sandstone is uncertain, but many exposures display upward gradation to clean, pinkish to white or brown, orthoquartzitic, well-bedded arenites typical of the Keeseville member of the unit in this region. Such an upward progression may be seen in the second large roadcut on the right, up the hill. The large, reddish-brown cut opposite this consists of well-stratified, quartz pebble conglomerates, with thin orthoquartzitic sandstones on top. A small knob of marble occurs at road level near the lower end of the cut, where clayey sediment has been found (cave floor?).
Studies by the New York State Geological Survey indicate that the Potsdam Sandstone and the overlying Theresa and younger units dip away from and do not pinch out toward the Adirondack Dome. It is assumed; therefore, that these units once formed a continuous blanket over the region, which has been largely denuded during the geologically recent, and continuing doming of the mountains. It is mainly in thick karst fillings like this near the edge of the Precambrian terrain, that the basal Potsdam, or pre-Potsdam, sedimentary rocks have been preserved.

Dark gneiss left.

Dark gneiss, perhaps meta-turbidite
Begin Richville Bypass. Dark gneiss, perhaps meta-turbidite, with apparent preserved small-scale graded bedding.

STOP 4. End of Richville Bypass.
Dark red cut at right is puzzling, and it is hoped discussion will be generated among field trip participants. The material is similar to, but much more hematitic and voluminous than that of the unquestioned sinkhole fillings. More "normal" Potsdam sandstone may be found at the top of the cut. Conglomeratic sandstone dikes in marble may be found at the upper end of the opposite cut. The left half of that cut, however, consists of a whitish feldspathic (metapegmatite) rock outwardly resembling the marble, and containing several thin, diopsidic marble sills or dikes. What do you suppose is the origin of this rock? See if you can find the contact with the marble.

Begin several marble cuts
Begin several marble cuts with abundant small reddish conglomeratic sandstone infillings. From here to Gouverneur the road traverses rolling countryside with predominantly NE-trending ridges underlain by gneiss, and marble valleys.

Enter Gouverneur.
Enter Gouverneur. Note the several buildings in town constructed of Gouverneur marble, essentially the same as the marbles we've been looking at.

Begin several marble cuts.

Potsdam Sandstone cut right, with bowl-shaped structure at top.
These structures are commonly found intermingled with cylindrical structures near the base of the Potsdam over marble. They have long been thought to result from the rearrangement of sand by sifting into underlying small solutional pockets in marble. They are copiously developed along the Cream of the Valley Road north of the Rock Island Road cut.

Begin several marble cuts, some with dark calc-silicate layers.

Sand and gravel quarry in kame
Marion Construction Materials sand and gravel quarry in kame, right. Well rounded cobbles, abundant cross-bedding.

Pinkish Alaskite at x-road, with glacial grooves on top

Optional stop. Begin several cuts of marble
Begin several cuts of marble with infolded and segmented calcsilicate layers, in direct contact with biotite granite gneiss.

Intersection in the Village of Antwerp, cuts in migmatitic gneiss.
Intersection N.Y. 411 in the Village of Antwerp, with cuts in migmatitic gneiss. Pass over Indian River. Turn right to Theresa. The road along the way (about 10 miles) passes by numerous outcrops of gneiss and marble. The gneiss tends to form rounded, elongate, barren knobs, with streamlined, glacially smoothed forms.
2011: On the older maps Route 26 joins at this intersection. Currently, both 411 and 26 join near Philadelphia.

STOP 5. Theresa Reservoir
The cliff on the left side of the road near the reservoir, again, is a reddish conglomerate and breccia similar to those you have seen in sinkhole deposits. Massive and poorly bedded, it is but one of a wide variety of conglomerates and breccias occupying the interval between Proterozoic rocks and "normal" Potsdam Sandstone in the Lowlands Adirondacks. In this one, pebbles are sparse except near the center base of the cliff. Upwards in the section, the rock becomes sandier, better stratified, and cross-bedded. The underlying rocks are concealed by the cliff, but can be seen just below the Niagara Mohawk dam nearby. The rocks are all steeply-inclined gneiss and metaquartzite. The Indian River drops more than 80 feet here. The dam was built in 1929 on the site of the original, 65-foot "High Falls" - almost certainly a fault scarp. Raising the water to its present level eliminated the 15-foot "Upper Falls" that were located a short distance upstream.

Tableland capped by flat-lying, durable Potsdam Sandstone
Theresa lies close to the Paleozoic boundary, and here the road climbs onto an extensive tableland capped by flat-lying, durable Potsdam Sandstone and occasional outliers of Theresa sandy dolostone perched on top of it.

Pass several cuts in Theresa Formation.

STOP 6 at Plessis
The clean surface of the Potsdam Sandstone here offers a remarkable display of well-preserved glacial scour features, including polish, striae, chatter marks, and large grooves. Also visible on the smooth surface are abundant arcuate cross-bed laminae. The gentle undulation of the Potsdam surface seen here is barely concealed beneath thin soil cover between here and Alexandria Bay. Continue north on N.Y. 26 past cuts of light gray, thin-bedded Theresa Formation.

The flatness of the tableland is most evident here
Browns Corners. The flatness of the tableland is most evident here, when viewed across open pastureland with less than 10 feet of relief. Continue left to Alex Bay.

Boat Ride
The purposes of the boat ride are: 1) to give us a welcome relief from bus travel; 2) to allow time to eat lunch; 3) to view some of the magnificant Thousand Islands, and 4) to view, from the boat, exposures of flat-lying Potsdam Sandstone over granitic gneiss at the southern tip of Wellesley Island.
The boat trip will take us first through open water under the beautiful Thousand Islands suspension bridge to the end of Wellesley Island. Then we will wend our leisurely way back through the cluster of scenic islands near the American shore.
It is now believed that the Proterozoic terrain of the Thousand Islands was once blanketed with flat-lying Potsdam Sandstone and younger Paleozoic units, as was that of the Adirondack Mountains. In historical perspective, the Himalayan-sized Ancestral Adirondacks, resulting from the Grenville Orogeny approximately one billion years ago, had by Potsdam time, been worn down to a peneplain, leaving the region vulnerable to marine submergence. Transgression of the so-called "Potsdam Sea" beginning in late Cambrian(?) time (ca. 525 m.y.a.). set the stage for shallow marine deposition of sand, carbonates and clays, the parent materials for the lower Paleozoic units that now rim the Adirondacks and Frontenac Arch. Erosional decimation of these once continuous deposits has been accomplished only in the last 10 million-or-so years as a result of the still-continuing doming of the Adirondacks and concurrent uparching of the Frontenac Arch. Presently, only a few scattered remnants of Potsdam Sandstone remain on the flanks of the Arch in the Thousand Islands region, and on its northwestward and southeastward extensions into Canada and New York, respectively. We will view one of these patches from the boat at the southern tip of Wellesley Island. Farther upstream toward Lake Ontario, a much larger remnant has survived erosion on Howe Island, and still farther, Wolfe Island, the largest of the Thousand Islands, is completely blanketed with limestones belonging in the medial Ordovician Black River and Trenton Groups (the lower Ordovician Theresa and Beekmantown are missing). An exposure of the Proterozoic / Potsdam unconformity that is essentially similar to that of Wellesley Island will be examined at close range at STOPs 7 and 8 later.
The Proterozoic rocks of the Frontenac Arch have also been deeply eroded as a result of the ongoing uplift, leaving only the more resistant knobs projecting as islands or shoals. The islands are generally elongated parallel to their strong northeasterly structural grain, a trend that is even more evident in the marble-gneiss outcrop patterns of the Lowlands Adirondacks. For the most part, the islands are lovely, forested, projections of attractive, pink leucogranitic (alaskitic) Alexandria Bay Gneiss (visible mainly along the shores). Most of them take the form of glacier-polished sheepbacks, with gentle stoss sides facing northeastward and steep cliff sides opposite, indicating a southwestward upvalley ice advance. The islands are largely devoid of glacial debris, except for some minor till hills, and thin ground moraine. This scarcity probably reflects, at least in part, the severe erosion resulting from rapid drainage of Lake Iroquois through the St. Lawrence Valley, after that outlet was opened by recession of the Wisconsin ice sheet.

STOP 7. Alexandria Bay Roadcut
The northeastern (downhill) end of this cut exposes an angular unconformity of profound dimensions, encompassing a time gap of approximately 600 million years between Proterozoic gneisses and basal Potsdam Sandstone. It enables comparison between the contemporaneous erosional surfaces developed on gneisses and those of the marbles seen earlier.
The Proterozoic rocks beneath the unconformity consist of massive, pink, alaskitic gneisses and dark, banded gneisses with steeply dipping foliation. These are extensively weathered, especially in a narrow zone directly beneath the base of the Potsdam. Note, also, that the upturned edges of the gneiss bands are buckled below the contact; This zone may represent a fossil inorganic soil developed on the pre-Potsdam erosional surface, or preferential, post-depositional, groundwater leaching along the contact (which may also explain the extreme friability of the basal sandstone beds). Can you suggest any other possibility?
Features nearly identical to these have been reported on the other side of the Adirondacks near Putnam Center, N.Y. by Van Diver (1980). The pre-Potsdam erosional surface appears to be structurally intact and rises slightly to the northeast (downhill on the road), forming a boss, or knoll preserving the original relief of the depositional surface. Basal sandstone beds drape over the southwestern slope of the knoll, and pinch out against it, while proximal younger beds thin out over the top of it. Upwards in the section, the bedding becomes increasingly horizontal and uniformly thick. Cross-bedding, in general, is poorly developed, but is more prevalent in the upper part of the section.
The basal Potsdam beds at this roadcut have been described by Kirchgasser and Theokritoff (1971), as mature orthoquartzites with scarce clasts of Precambrian rocks, suggesting an origin by reworking of fluvial sands by an encroaching sea. On a regional scale, marine transgression set the stage for leveling of the irregular Proterozoic surface by filling in all of the karst depressions like those seen earlier, and covering over projections in gneisses such as that of the Alex Bay Cut.

Cross-bedded Potsdam Sandstone cut.

STOP 8. Proterozoic/Potsdam unconformity.
This cut shows features similar to the Alex Bay cut, but here the basal sandstones display better-developed, low-angle~ crossbedding. The purpose of this stop is to allow comparisons between these two exposures of the unconformity, as developed on gneiss. From here, we will proceed directly to Ogdensburg, and then to Potsdam.

Begin several excellent exposures of gneiss.

Cuts in lower potsdam Sandstone with distinct lower and upper lithofacies (see Selleck, this volume).
Continuing northeastward, the cuts along the highway expose progressively higher stratigraphic sections of the Potsdam and Theresa Formations. Contact between the two units is exposed at Chippewa Bay (Selleck, STOP 3, this volume; Kirchgasser and Theokritoff, 1971).

A good overlook to view the river is located a at Cedar Point.

3: SELECTED MINERAL OCCURRENCES IN ST. LAWRENCE AND JEFFERSON COUNTIES, NY
George W. Robinson
National Museums of Canada
Mineral Sciences Division, NMNS
Ottawa, Ontario, Canada K1A OM8
Probably no other region in the State of New York is better known for its wealth of mineral occurrences than at St. Lawrence, Jefferson, and Lewis Counties. Indeed, many are among North America's most famous and classic localities (Beck, 1842; Dana, 1877; Kunz, 1892; Jensen, 1978; Robinson and Chamberlain, 1981). The vast majority of these occurrences are found within the Grenville metasediments, which are geologically complex and host a wide variety of mineral assemblages. It is the intent of this trip to acquaint the participant with a selection of localities that provide a variety of geological environments, are of mineralogical and historical interest, and will hopefully afford good collecting opportunities. For additional information, the reader may wish to consult some of the available collecting guides (Agar, 1921,& 1923; Robinson, 1971; Robinson and Alverson, 1971; Van Diver, 1976).

3: SELECTED MINERAL OCCURRENCES IN ST. LAWRENCE AND JEFFERSON COUNTIES, NY

STOP 1: The Powers Farm at Pierrepont
Many of the most interesting localities in Northwestern New York and Southeastern Ontario are in contact zones between various Precambrian rocks and Grenville marble, and particularly in their associated calcite vein-dikes (Robinson, 1982; Moyd, 1972). Such contacts are often of a local nature, and host a wide variety of complex skarn-like mineral assemblages. The Powers Farm has one such occurrence.where a quartz-tourmaline-biotite pegmatite (?) is in contact with coarsely crystallized calcite.

STOP 2. The McLear Mine at Dekalb Junction
Continue to the first road to the right and park. The McLear Mine is immediately to the southeast of this intersection.
The McLear pegmatite was discovered in 1907 by J.H. McLear, on the Kilburn Farm, 3.9 miles southwest of Dekalb Junction (Cushing and Newland, 1925; Shaub, 1929). The ore consisted of pure, white microcline perthite, which was hand cobbed and shipped to Rochester and Trenton for use in the pottery industry. By 1929 the Green Hill Mining Company had developed both open cut and underground workings, and shipped over 120,000 tons of pottery grade feldspar (Shaub, 1929). By 1938 mining ceased (Tan, 1966).
The main pegmatite is a lens shaped body 850xl15x60 feet with a spacial orientation generally paralleling the regional NE-SW structural trend of the enclosing Grenville metasediments. Radiometric age determination from uraninite indicates the pegmatite was emplaced in the middle Precambrian at 1094 m.y. (Shaub, 1940). The mineralogy of the pegmatite is unique, and suggests a complex origin by successive replacement of the host crystalline limestone by magmatic solutions probably emanating from nearby granites (Shaub, 1929). Based on mineralogic and textural zonation the apparent paragenetic sequence is diopside + tremolite + quartz + feldspar + quartz, giving rise to a gradational contact between the pegmatite and wall rock. Later hydrothermal alteration caused slight sericitization of the feldspars and serpentinization of the diopside and tremolite.
Minerals that may be collected relatively easily include: diopside, microcline, mica, quartz, titanite and tremolite. Allanite, apatite, calcite, chlorite, goethite, hematite, kaolinite, magnetite, molybdenite, pyrite, pyrrhotite, rutile, serpentine, talc, thorite, thucholite, tourmaline, uraninite, and zircon occur more sparingly.

STOP 3. The Gem Diopside Mine at Dekalb
From the McLear Mine proceed south (right) on the road to Bigelow for 1 mile and park. The locality for gem diopside is on the ridge across the field, east (left) of the road. This locality is on private land, and is NOT regularly open for collecting!
This locality has produced some of the finest crystals of gem diopside known. Early specimen labels may give the locality as the Mitchell Farm, as Calvin Mitchell was probably the first person to find and distribute specimens in the 1880's. By 1889 the famous mineral dealer George L. English acquired the mining rights, and by 1892 George F. Kunz had described crystals over 3 inches long that would yield gems up to 30 carats. For unknown reasons the deposit was not worked again until 1967 (Szenics, 1968), and intermittently thereafter (Robinson, 1973).
The mine is situated in a northeasterly trending ridge of diopside-tremolite-quartz schist, approximately 4 miles northeast of the Village of Richville. The relative proportions of diopside, quartz and tremolite vary considerably, and the quartz locally forms tightly folded bands. The gem pockets tend to form within the diopside rich layers and along tremolite veins 'which follow joints perpendicular to the strike. The pockets are often filled with a compact gray talc and acicular tremolite. The apparent paragenetic sequence is diopside + tremolite + talc + quartz ± calcite. Other species that occur less commonly are pyrite, plagioclase, and datolite (reported but unconfirmed). The diopside invariably occurs as euhedral prismatic crystals with well developed forms {100}, {110}, {001}, {101}, and several {Okl} and {hkl} prisms (Figure 1).

STOP 4: The Coal Hill Vein at Rossie
The Rossie Lead Mines are one of the oldest and most famous North American mineral localities. The large crystals of calcite and galena these veins once produced are indeed classics. The Coal Hill Vein is perhaps the best known and is probably a relatively low temperature hydrothermal calcite-galena vein that intruded Precambrian granite in post-Ordovician time.
Park in the field to the right at the Coal Hill Vein.
Mining first commenced at the Coal Hill Vein in the winter of 1836, and continued throughout the Civil War. The vein was excavated over a length of 600 feet and to a depth of 200 feet. By 1868 operations ceased, after producing over 1625 tons of lead (Cushing and Newland, 1925). During this period many fine, large crystals of galena and calcite were recovered, and soon became the object of much discussion (Beck, 1842; Emmons, 1842; Dana 1877). Fortunately a number of excellent specimens found their way into prominent collections and may still be seen today at the American Museum of Natural History, Harvard University, Hamilton College, and the New York State Museum. The complexity of forms on some of the calcite, pyrite, and fluorite crystals is nearly unrivaled (Figures 3-5).
The vein consists primarily of calcite with disseminated galena, and occupies a nearly vertical, east-west fault in the enclosing Precambrian granite. Inclusions of partially altered wall rock form a brecciated zone near the contact. By comparison to nearby veins and similar deposits in Ontario, emplacement is thought to be post-Ordovician (Beck, 1842; Smyth 1903; Wilson, 1924). Whether the mineralizing solutions originated from below as relatively cool, chemically inactive fluids, descended from above through meteoric concentration from the overlying Paleozoic rocks, or were perhaps derived from both meteoric and magmatic waters remains an unanswered dilemma (Smyth, 1903; Buddington, 1934; Wilson, 1924; Uglow, 1916).
Recent SEM studies have unveiled the presence of an unusual assemblage of anatase, albite, synchysite, and cerian epidote occurring in micro cavities and fissures in both the vein material and altered wall rock. Hopefully, a continuing investigation will help clarify the origin and paragenesis of these veins (Robinson and Chamberlain, in prep.).
Nearly all the following species may still be collected from the dumps, but not in the quality that was produced when the mine was operating: albite, anatase, anglesite (?), calcite, celestine, cerussite, chalcopyrite, fluorite, galena, microcline, quartz, sphalerite, stilbite (?), and synchysite.

STOP 5. The Sterling Mine at Antwerp
Stop at the Villeneuve Farm on the right side of U.S. 11 to obtain permission to enter the Sterling Mine property.
Continue north on U.S. 11 to the Sterling Rock Shop and mine road entrance on the right. Park here and walk down the old mine lane approximately 350 yards to the mine.
The Sterling Mine was the first U.S. locality for millerite, and is often regarded as having produced some of the world's best specimens of that species. The mine lies near the middle of a group of hematite deposits known as the Antwerp-Keene belt (Buddington, 1934). Mining first began in 1836 and continued until 1910, creating an open pit 500 feet long, 175 feet wide and 115 feet deep, that produced hundreds of thousands of tons of ore (Smock, 1889).
The geology of this deposit is complex, and a detailed mineralogical study is currently in progress (Robinson and Chamberlain, in press). The mine is situated along a marble-gneiss contact, and the ore is intimately associated with a heavily slickensided quartz-chlorite rock which is thought to have formed by the replacement of the gneiss by corrosive, iron-rich solutions derived from the decomposition of underlying pyritic schist (Smyth, 1894; Buddington, 1934; Prucha, 1957). Both the chloritic rock and marble appear to have been replaced by hematite resulting in a gossan-like structure which was then preserved by a capping of Potsdam sandstone. Open spaces were filled with hematite and quartz, and possibly other species not preserved. Subsequent recrystallization of the quartz and hematite at relatively low pressure and temperature is suggested by the presence of Fe-talc and stilpnomelane, and is supported by fluid inclusion studies (Robinson and Chamberlain, in press). Further changes in the composition, eH and probably pH of the mineralizing solutions are evident from the presence of magnetite pseudomorphs after hematite, both Fe(II) and Fe(III) rich stilpnomelanes, Fe-talc and various sulfide and carbonate phases.
Minerals that can readily be collected are hematite, magnetite pseudomorphs after hematite, quartz, stilpnomelane ("chalcodite"), Fe-talc, siderite, goethite, calcite, ferroan dolomite, and more rarely millerite and jamborite (?), all of which occur as well formed crystals in vugs in the crystalline hematite-quartz ore. Early reports of cacoxenite and ankerite can not be confirmed, and likely resulted from the misidentification of stilpnomelane and siderite (Robinson and Chamberlain, in press).

4: STRATIGRAPHY, STRUCTURE, AND GEOCHEMISTRY OF GRENVILLIAN ROCKS IN NORTHERN NY
James D. Carl
S.U.N.Y. Potsdam
William F. deLorraine
St. Joe Resources Company
The geology of the northwest Adirondack lowlands is characterized by northeast-trending belts of highly deformed rocks, chiefly marbles and gneisses, all metamorphosed to upper amphibolite facies grade during the Grenvillian Orogeny. A clear picture of the structure and stratigraphy of this region has proven elusive due to effects of recrystallization, multiple folding, anatexis and magmatism during metamorphism.
Several different structural and stratigraphic models have been proposed which illustrate the diversity of opinion surrounding these rocks. Engel and Engel (1953) believed the stratigraphy to be part of the overturned, southeastern limb of a regional anticlinorium whose upright limb lay to the northwest in Canada. They recognized five major stratigraphic units which, from NW to SE in order of decreasing age, include the following:
1) Black Lake metasedimentary belt; 2) Gouverneur, or Lower Marble; 3) Major Gneiss belt; 4) Balmat-Edward or Upper Marble; and 5) Harrisville-Russell belt (see map, Figure 1 and cross-section, Figure 2).
A model by Lewis (1969) included two major marble units, separated by the Major Gneiss, which were continuous across the northwest Adirondacks but repeated in linear, northeasterly belts by tight, upright folds. More recently Foose (1974) and Wiener (1981) postulate that there is but one carbonate horizon repeated by multiply-refolded nappes.
There seems to be agreement that alaskitic gneisses (leucogneisses) which core domical structures in the northwest Adirondacks constitute a basal horizon over which marble and gneiss precursors were deposited. Geochemical data and recent field mapping reveal a relict stratigraphy consistent with an ash flow tuff origin. Geochemical data from the Major Gneiss are consistent with an origin as slightly reworked, dacitic tuff. Results of mapping by St. Joe Resources Company geologists (including deLorraine) are best interpreted as two distinct carbonate units separated by the Major Gneiss. The basal marble, here termed the Gouverneur marble type, directly overlies the leucogneisses and comprises the Engels' Black Lake, Gouverneur (Lower Marble), and Harrisville-Pitcarin marble (part of the Balmat-Edwards, or Upper Marble of the Engels). Major Gneiss overlies this marble and, in turn, is overlain by an upper marble, hereby called the Balmat-Edwards marble type. This model is similar in some respects to that of Lewis (1969).
The purpose of this field trip is to investigate regional stratigraphy and structure from the perspective given here. We will point out numerous areas where further investigation is needed, particularly with regard to the role of magmatism during (before?) metamorphism. We will also discuss the origin of some of the gneissic rocks in view of recent geochemical data.

STOP 1. New roadcut on Route 812 north of Harrisville near bridge over Oswegatchie
We start our trip in the Harrisville-Pitcarin marble belt adjacent to the Highlands - Lowlands boundary which lies just to the southeast. Marbles here belong to the Lower marble belt (Gouveneur marble type) and overlie the Clark Pond leucogneiss body which lies to the southwest. Formerly, this belt was included in the Upper or Balmat-Edwards marble belt of the Engels. These marbles consist of coarse-grained, light gray and white, banded, graphitic-calcitic marbles with accessory brown tourmaline, local chondrodite and diopside. A thin layer of Major Gneiss between Geer's Corners and Pitcairn separates the Lower (calcitic) marble from the Upper (silicated-dolomitic) marble to the north toward Fullerville and Balmat. Note the lobate form of the intrusive body of quartz-syenite exposed on the right-hand side of the outcrop.

STOP 2. Zinc and Talc mines
STOP No. 2A. St. Joe Resources Co. #2 Mine area at entrance to Balmat #2 mine, Route 812, Gouverneur quadrangle.
Exposed here in the core of the Balmat syncline is unit 14, one of 15 carbonate units comprising the stratigraphic section at Balmat. Overall plunge of the syncline (overturned) is NNW. Note the profusion of isoclinal folds, rootless fold hinges, transposed layering, and fragmented silicate layers in marble. Look for bladed tremolite clusters, diopside, quartz, serpentine, and dolomitic and calcitic marbles. Contrast the composition of this marble with that at STOP 1. Nearby is the old #2 mine-mill complex, now unused because milling operations have shifted to the new #4 mine area. However, #2 shaft still serves as an access and escape route for the #2 mining area. This is the site of original mining in the Balmat district, having begun in 1930, although sphalerite showings were reported as early as 1838 by Ebenezer Emmons.
STOP No. 2B. Area to right of gate at entrance to #2 mine area; old American Talc shaft.
Exposed here is Unit 13, a talc-tremolite-anthophyllite schist. Suggested by Engel (1962) as a shear zone metasomatically enriched in Mg, it more likely is a siliceous meta-evaporite unit. Its distinctive appearance, composition, and continuity make it an excellent marker for use in unravelling the structure and stratigraphy of the Balmat district (deLorraine, 1979). This rock is mined for use primarily as paint filler and for use in ceramics.

STOP 3. Pump house road, Sylvia Lake
Entrance at Gouverneur Talc Co. parking lot. Proceed down road almost to lake; park near dirt road with gate on right.
Units 11 and 12 are exposed here. Unit 12 is a relatively pure dolomite marble. Unit 11 is representative of most of the silicated dolomitic marble units in the district and is composed of well-layered quartz-diopside (est. 50-65%) and dolomite with minor interlayers of calcitic marble. In a nutshell, Balmat stratigraphy is characterized by alternating pure dolomites (such as Unit 12) and silicated dolomitic marbles (such as Unit 11) for a total of 15 carbonate units. Anhydrite is also important; a large body underlies Sylvia Lake

STOP No.4. Popple (Poplar) Hill migmatite
Best exposure of major gneiss in the northwest Adirondacks. A good introduction to problems of origin for migmatite and for the protolith of a widespread rock type in the Canadian Shield. This oligoclase-K-feldspar-quartz-biotite, sometimes sillimanite-garnet gneiss lies between the carbonate units and is traceable for more than 70 km from Philadelphia, New York to Colton. It is consistently gray and fine-grained except where strewn with convolute quartzo-feldspathic veins, boudins, K-feldspar porphyroblasts, amphibolites and thick sill-like bodies of leucogneiss, all of which are visible at this outcrop.
Carl (1981) believes that much leucosome is locally derived and not introduced from outside sources. He disagrees with conclusions reached by Engel and Engel (1960 a,b) that the effects of metasomatism are increasingly pronounced to the northeast where metamorphic grade approaches granulite conditions (Stoddard, 1981). Changes in rock chemistry occur over short distances as is illustrated at this outcrop. It is not easy to demonstrate changes of a more gradual nature over great distances.
We will point out disruptive contacts between banded gneiss and massive, subporphyroblastic rock that contains angular fragments (xenoliths?) of darker rock like that found in Hermon gneiss (see our "optional stop"). deLorraine first recognized this rock last summer, which illustrates either 1) that the second decade of examining the same rock outcrop is most informative, or 2) that the rest of us are essentially blind. This massive rock is more mafic, less potassic and is enriched in Sr, Yt Ba, and Th relative to banded gneiss (Table 1). Rb content is about the same. Note that the high Ba and Sr content of massive rock is also a characteristic of its K2O-enriched leucosome.
Amphibolites are generally conformable and in sharp contact with banded gneiss. They contain biotite-selvaged leucosome that resembles its host in plagioclase content and low Ba and Rb.
Leucosome in banded gneiss is of granitic composition with K-feldspar dominant over plagioclase and 25-35% modal quartz. Like the host gneiss, leucosome is enriched in Ba, Rb and Sr. Textures range from xenomorphic granular to strongly flaser and cataclastic. Porphyroclasts are surrounded by wreaths of mortar similar to that surrounding K-feldspar augen in the Hermon gneiss. A possible mode of origin is that of partial melting along shear zones at some early stage of metamorphism and folding.
What was the protolith of the major gneiss? Perhaps dacite volcanics that were slightly weathered and reworked as proposed for paragneiss in NW Ontario by van de Kamp and Beakhouse (1978). There is at least one locality where cross bedding seems preserved. Sillimanite content is variable and may occur as thin lenses or in thin sections, but Al2O3is generally low for a shale. Harker diagrams show igneous trends (except for Na and K) and the rock lacks enough CaO, Cr and Ni to represent the composition of many graywackes. An Na/K ratio of 1.0 is obtained instead of 1.2-1.4 characteristic of graywackes when leucosome is included in an assessment of average outcrop composition (Carl, 1981). The massive rock at the Popple Hill outcrop with its more mafic chemistry may represent a volcanic feeder for material now incorporated in the adjacent banded gneiss.

STOP 5A. Small outcrop on north side of road, "Steer's Head"
Gouverneur marble and gray, granitic intrusive rocks exposed here. Note the light gray inclusion of marble (shaped like a steer's head) in the darker gray granitic rocks. Similar gray granitic rocks are well exposed along Route 11 as far south as Antwerp; this string of granitic bodies extends as far northward as Moss Ridge on the Bigelo quadrangle. North of Battle Hill at the south end of Moss Ridge (Gouverneur quadrangle), the gray gneiss undergoes a transition from gray to splotchy gray and red, to pink/red granite. Its red coloration north of Battle Hill causes the unit to resemble the basal leucogneisses. We suggest that Moss Ridge is the northerly extension of the granite intrusive belt and probably constitutes a sill-like body within Gouverneur-type marbles. As such, it is unrelated to the basal leucogneisses as was proposed by Foose (1974). Moss Ridge also lacks a pronounced positive magnetic anomaly that is common to other leucogneiss bodies.

STOP 5B. "Train wreck" Outcrop - Fragments of "basaltic" rock in Gouverneur marble.
Clustering of blocks and their rectangular outline suggests disruption of a basaltic dike during folding. Mineralogy of the dike, however, is adjusted to metamorphic conditions. Plagioclase is absent in contact zones in the dike rock which contains meionite scapolite, diopside, microcline, sphene, tremolite, biotite, quartz, tourmaline and apatite. This roadcut also contains a basalt dike that is not disrupted.

STOP 6. Hyde School leucogneiss and amphibolite at the southwest end
STOPs No.6 and 7. The Hyde School "alaskite" body: leucogneiss and amphibolite at the southwest end, and tonalite at the northern edge along the Hyde road, Pope Mills quadrangle.
The Hyde School is the best exposed of several domical leucogneiss occurrences in the Northwest Adirondacks. Many years ago A. F. Buddington proposed that the gneisses represent granitic intrusions into anticlinal crests (phacoliths) during Grenville folding and metamorphism. The Hyde School body, however, is anything but a simple dome. Isoclinally folded and refolded amphibolite layers are shown to mimic the larger structures, and there is evidence that all "domes" are protuberances of a single, multiply-folded, lower stratigraphic unit present throughout the lowlands. The Hyde School body has been recently mapped by Erv Brown.
The blunt, southwesterly-plunging end of the Hyde body overlooks a solution valley in the surrounding Lower Marble unit. Amphibolites interlayered with leucogneiss (alaskite) are virtually undisturbed at this locality. Some are broken with coarse-grained quartz and feldspar occupying the break. Extension in the direction of plunge or laterally in the plane of foliation produced tension within these relatively competent layers.
Carl and Van Diver (1975) recognized a stratigraphy of sorts within the leucogneiss and made comparisons of major element chemistry with ash flow tuffs. The presence of dark tonalite-trondhjemite gneiss units within a dominantly granitic gneiss sequence was compared to the capping of ash flow tuff sequences by later, more fluid, plagioclase-rich extrusives. The lower parts of ash flow sequences have rhyolitic tuffs derived from the uppermost, most differentiated portion of the underlying magma chamber. The plagioclase cap rock represents a later outpouring of more fluid magma at greater depth. The stratigraphic sequence on the surface, thus, represents an inversion of the zonation that existed in the underlying magma chamber (Figure 3).

STOP 7. The Hyde School tonalite at the northern edge
Units of tonalite-troudhjemite occur along the western margin of the Hyde School exposure and in the center of the southern dome. If these are truly the cap rock of ash flow tuffs, then a walk northwardly along the Hyde road is upward in the stratigraphic sequence. It is also a look deeper into the magma chamber that gave rise to that sequence.
Support for an ash flow tuff origin has recently come from geochronology studies of Bob Lepak (1983) and Tom Maher (1981), students of Norman Grant at Miami University of Ohio. They find a crystallization age for precursors of the leucogneiss at 1263 + 25 Ma and an initial 87Sr/86S ratio of 0.7033 + 0.4. Samples with high Rb/Sr ratios give evidence for open system behavior of Sr that is proposed (by other workers) to have occurred in silicic volcanics. This Sr loss is attributed to factors such as the reordering of K-feldspar structural state during cooling of the tuffs, or by Sr loss in fluids prior to or during metamorphism.
Carl has analyzed rock samples taken along the Hyde road from granitic leucogneiss into the tonalite-trondhjemite unit. Chemistry is given with respect to lithology in Figure 2. Note the change from siliceous to more mafic chemistry toward the plagioclase unit and an "upward" increase in MgO, CaO, Na2O, TiO2, Ni, Cu, Sr, and Ba. There is a decrease in SiO2, K2O, Rb, Y, Zr, Nb, Pb, and Th. Analyses by Calvin Pride, University of Ottawa, show less total rare earth element content (and no negative Eu anomaly) in the caprock than in the underlying leucogneiss. The caprock is slightly enriched in light REE relative to heavy REE than is the underlying leucogneiss (La/Yb ratios of 9.7 vs. 8.0).
These trends are remarkably similar to those recorded in a vertical sequence of the Bishop Tuff in California by Wes Hildreth (1979). The lower, siliceous part of that sequence is enriched in the small, highly charged cations Y, Nb, Th, and La. It is also enriched in Rb and has a strong negative Eu anomaly. Ba and Sr enrichment occurs in the more mafic caprock. In contrast to the leucogneiss sequence, however, Hildreth reports the caprock enriched in K over Na (odd!) and in Zr content.
Large portions of the leucogneiss sequence must have been rapidly extruded and deposited as is the case for individual flows in a tuff sequence. Deposition of other portions, however, must have occurred intermittently and in water because of interlayering with numerous thin amphibolites (mafic tuffs?), calc-silicates and garnet-sillimanite gneiss. Extensive compaction, recrystallization and folding evidently obliterated all textural evidence of the precursors.

5: THE TRENTON GROUP OF THE BLACK RIVER VALLEY
Robert Titus
Hartwick College

5: THE TRENTON GROUP OF THE BLACK RIVER VALLEY

STOP 1. Park beyond bridge which crosses Mill Creek.
About 90 m of the Trenton Group are exposed at this location. The 16 m of strata below the bridge display the upper Kings Falls Limestone and all of the Sugar River Limestone. Upstream there is a complete exposure of the Denley Limestone. There is only one short break in the section. Finally, the entire Steuben Limestone can be seen along the upper reaches of Mill Creek. The Steuben Limestone begins just below the quarry. Thus, most of the lower Trentonian transgression and all of the middle Trentonian regression are represented at this location.

STOP 2. Park beyond the bridge which crosses the Deer River.
About 17 m of the uppermost Trenton Group Hillier Limestone is exposed here. This may be the most complete section of the Hillier Limestone. The rocks become progressively more micritic towards the top reflecting deepening seas. The outcrop thus records the upper Trentonian transgression.

6: A FEW OF THE BEST OUTCROPS IN THE NORTH COUNTRY
BY
James D. Carl, S.U.N.Y. Potsdam

STOP 1. Trinity Episcopal Church, and a walk into the Potsdam business district.
Our tour will begin with Fall Island and Trinity Church and will include a short walk downtown. The community has recently been chosen for a Main Street award for its Market Street renovation project. A number of buildings have been restored or built for compatibility with the architecture of the late 1800s, the period of greatest construction in the village. This two-block section of Market Street and a portion of Raymond Street were placed on the National Register of Historic Places in 1979. Here are sandstone and brick buildings (some marble trim) of Italianate and Greek revival and other styles including the simple slab construction of the earliest commercial sandstone building (1821) that houses Eugene Earle, Jeweler. Note also, the slab and binder construction (1840) of Page One Bookstore.
Background
Little was known about the northern Adirondack region at the close of the Revolutionary War. Carlton Island and Fort Oswegatchie (Ogdensburg) were still occupied by the British, and the north shore of the St. Lawrence River was dotted with settlements of Tory refugees and their families. According to Marguerite Chapman (1969), downstate New Yorkers felt the need to establish a buffer region between English Canada and the Mohawk Valley. Settlements south of the St. Lawrence River would act as a deterrent and give warning of potential invasion from the north.
The state legislature acted to provide for the sale of wilderness land and to appoint land commissioners for its disposal. Townships of 100 square miles were created instead of the 36 square mile block adopted by the Federal government in 1785 as the fundamental surveying unit for western lands. Evidently the state government was reluctant to set up the administrative machinery necessary to sell the land in small parcels. An act of May 25, 1787, established five townships along the south shore of the St. Lawrence River and five to the south of these. Following good advertising procedures the land commissioners named some of the towns after old world cities: Louisville, Stockholm, Potsdam, Madrid, Lisbon, Canton, DeKalb, Oswegatchie, Hague (Morristown), Cambray (Gouverneur).
Public notification of the forthcoming land sale was notoriously and perhaps deliberately hurried. The announcement first appeared in the Albany Gazette on June 7, 1787, for a sale which was to be held on the 10th of July in New York City. Millions of acres were sold for a fraction of their value with a Detroit fur trader-turned-land speculator, Alexander Macomb, buying the lion's share of the pot (3,670,715 acres). Surveying, division and sale of Macomb's purchases began immediately, but evidently did not offset other financial problems because Macomb was imprisoned for debts in the 1790's. Among those solicited for land purchases were the royalty and wealthy of France. The Revolution in America was over. Northern New York promised beaver, wild grapes, maple syrup and even friends of like mind (?) and language in Montreal, a "short" boat ride down the St. Lawrence River. Winters were not discussed in detail.
The town of Potsdam was eventually sold to Garrit Van Horne, David M. Clarkson and their associates on November 18, 1802. The saga of the Clarkson family from Bradford County, York, England, begins in the North Country along with the Episcopal heritage represented by this church.
Trinity Church
In early years of the Village, a small frame building on Union Street served as a school during the week and as a community church on Sunday. By the l820s and early 30s Potsdam was a thriving community with buildings lining both sides of Market Street and stately sandstone houses along Main and Elm. Common worship of the early settlers had given way to organization and construction of churches such as that of Baptists, Methodists, Presbyterians and Universalists. Episcopalians were meeting at the St. Lawrence Academy, a three-story structure, 68 by 36 feet, built in 1825 of Potsdam sandstone and located on the site of the north end of Snell Hall on the downtown campus of Clarkson College.
Although the first Episcopalian priest is said to have visited the county in 1816, the first resident priest was called in 1834 with at least three members of the Clarkson family pledging funds for his support. The Reverend Richard Bury arrived from Ogdensburg, and the parish was formally organized under the name of Trinity Church on March 23, 1835.
The site chosen for construction of a church was Fall Island adjacent to and on the south side of the Parishville Turnpike Road. Thomas Clarkson offered stone from his quarry, free of charge, for the "neat gothic edifice of stone 44 by 64 feet." The original design for the building and name for the parish was taken from Trinity Church constructed in 1788 in New York City. The name also emphasized, for good measure, a theological distinction between Episcopalians and local Universalists. The building was completed and consecrated on a warm July afternoon in 1836. A procession that began at the Academy Was concluded with a sermon by Rev. Bury on Fall Island. An engraving of the church as it appeared in 1836 (Figure 1) shows that the church lacked the tall steeple possessed by its namesake in New York. Windows were plain glass, and the high-backed, rented pews were complete with doors. Colorful upholstering was installed by pew renters accustomed to long services, and several pews were reserved for "strangers."
The side walls are about all that remain of the original structure. These walls consist of horizontal layers that alternate rows of flat-faced sandstone blocks (slabs) whose bedding is laid horizontally with rows of blocks (binders) whose bedding is laid vertically. This layer by layer alternation added style and texture to a smooth wall and was said to give added strength. Compare the slab and binder construction with that of strictly flat slabs in the Earle Jewelers building on Market Street.
The simplicity of architectural style of this early church was not acceptable in the second half of the 19th century. Victorian tastes in these parts leaned toward "roughened" (ashlar) stone construction whereby soaring walls of massive stone could be topped or garnished by highly carved stone or wrought iron decoration. The ashlar stone fence in front of the church (1867) was a prelude of changes to come. An ashlar chapel was added in 1885 and the present facade was finished in 1886. The towers capped with ornamental stone are a tribute to the skills of quarrymen and stone cutters as well as to the faithful who paid the bills. A new spirit seems to have prevailed in the church. In 1886 the pews were declared free of rent.
Windows were installed and dedicated as donations became available in the l890s. Created by Louis Tiffany and Company of New York, the windows depict the designs of notable paintings such as Holman Hunt's "Christ the Light of the World." The beauty of these windows, accentuated by dark ash ceilings, is most striking from the inside on a sunny day. The present rector of the parish, the Rev. Canon James Pennock, is also mayor of the Village of Potsdam.

STOP 2. No. 1 Quarry of the Potsdam Red Sandstone Company
Much sandstone in buildings throughout the area was taken from quarries that were strung along both sides of the Racquette River south of Potsdam Village. Several sandstone houses (about the size of large log cabins) were built between 1309 and 1820 along the Back Hannawa Road. Much stone was hauled along this road in later years to construct the homes and businesses of Potsdam.
The qualities of Potsdam sandstone were highly praised in the 1850s. The stone was cheap, available and of pleasing red coloration. Elsewhere it may be white or gray. It was also durable and not as susceptible to spalling in case of fire as was granite building stone. Iron furnaces in Ontario and New York State had sandstone lining. Note, say various appraisers, the sharpness of outline in natural exposures that has lasted "several centuries." The stone occurs in even-bedded strata and cleaves into slabs with flat faces and straight edges. There is nothing in the rock to "nourish parasitical mosses." Walls made from this siliceous stone do not become moldy and decaying as is the case with walls of limestone in damp climates. This stone keeps its color, and the claim was made that exposure to air actually hardens it. Perhaps this is over zealous advertising; it may refer to the tight silica cementation that naturally existed once broken and loosened quartz grains were brushed away. This old quarry site is now the property of Niagara-Mohawk Power Co., but sandstone is still taken on occasion for patio or building trim.
Geologic Setting
The Cambrian Potsdam sandstone has been stripped from the Adirondack dome northward to the vicinity of Potsdam Village. Present distribution of that sandstone, however, is uneven. The small park on Fall Island across from the church is underlain by Precambrian amphibolite whereas the Cambrian Potsdam sandstone of No. 1 Quarry is located to the south near the border with the Adirondack highlands.
The Potsdam sandstone is of variable thickness. It was deposited upon an irregular surface of low hills and ridges of resistant Precambrian gneisses or as filling in sinkholes where bedrock consisted of marble. Erosion nearly to the level of that surface has left many sandstone outliers scattered here and there in the Potsdam area and in Precambrian portions of the northwest Adirondacks.
The Racquette River at the quarry site has cut a channel into glacial and deltaic sediment now exposed in the bluffs of Figure 4. The quarry is located within the sandstone outlier that was buried by till deposits during glacial advance and by outwash during glacial retreat. These sediments, in turn, were covered with a layer of magnetite-bearing quartz sand that, in the vicinity of Hannawa Falls, forms a large fan-shaped delta that opens to the north. These sands probably were deposited by the Racquette River when it entered a pro-glacial lake impounded between the highlands to the south and the ice front to the north. Retreat of the glaciers was accompanied by lowering of the lake level, by entrenchment of the Racquette River into the underlying sediments, and by exposure of the sandstone outlier at this quarry. The river at Hannawa Falls, thus, has a relatively steep-walled channel. To the north, however, the braided and meandering channel seems deliberately to avoid disturbing a topography of glacially-deposited hills that consist of ribbed moraine in varying stages of drumlinoid molding (Carl, 1978).

STOP 3. Sand terrace overlooking the St. Lawrence Valley
The transition from Adirondack lowlands to highlands occurs between Hannawa Falls and Colton. Our stop marks the southern boundary of the glacially deposited and overridden hills of the lowlands. Presumably (?) it also marks the southern extent of Fort Covington glaciation. We will walk under the power lines toward the edge of the terrace. Ottawa, the Gatineau hills and the other side of the Valley are out there but too far away to be seen. In language understood by corporate executives, the view from the top is superior, even if incomplete.
This area of transition is also the site of at least three sand terraces, the uppermost here at 800 feet elevation which includes the continuous but slightly higher surfaces (up to 900 ft.) along the Colton-Parishville road to the east. Compare terrace elevations here with those of other St. Lawrence Valley terraces as given in MacClintock and Steward (1965, p. 42). A second terrace remnant is preserved 200 feet below this level along highway 56 near Brown's Bridge road. The third or lowermost terrace begins at 580 feet and slopes northward in true deltaic fashion at Hannawa Falls. The delta ends abruptly at Sweeney Road, Potsdam quadrangle, in a northeast-trending, nearly undisected slope. This slope may represent middleset beds draped over the northeasterly end of a till hill. The contact between deltaic sands and underlying till or kame material is observed in gravel pits throughout the area.
Terrace sands consist of moderately well-sorted, angular, magnetite-bearing quartz sands that include heavy minerals derived from mountains to the south. The sands show cross bedding, channeling, climbing ripples and occasional boulders and gravel lenses. Similar sands underlie flat surfaces at lower elevations to the north including that at a recent housing development in Raymondville. Sand grains here are more rounded and contain less magnetite than at Colton. They were evidently recycled in the Champlain Sea. The uppermost terraces at Colton, Parishville and elsewhere along the Adirondack highland-lowland boundary represent the ancient shorelines of pro-glacial lakes that were impounded by retreating ice to the north. Imagine the view from this terrace at Colton roughly 10,000 years ago.

STOP 4. Gouverneur-type marble about 4 miles west of Canton on highway 11.
Recumbant folding of marble and a thin layer of silicate minerals within that marble. This is th e "snake" outcrop described in Brad Van Diver's book, Rocks and Routes of the North Country, and in field trip 2 of this guidebook. If the spray-paint antics of anguished lovers, religious zealots and fraternity pledges permit, we will observe a diopsidic reaction rim between the marble and the layer whose mineralogy includes quartz, microcline, sphene, phlogopite, pyrite, actinolite and tourmaline. The layer may have originated as air-born volcanic ash.

STOP 5. "Train wreck" outcrop. Fragments of "basaltic" rock in marble.
An outcrop eminently suited for black and white photography. Clustering of blocks and their rectangular outline suggests disruption of a basaltic dike during folding. Mineralogy of the dike, however, is adjusted to metamorphic conditions. Plagioclase is absent in contact zones in the dike rock which contains meionite scapolite, diopside, microcline, sphene, tremolite, biotite, quartz, tourmaline, and apatite. This lengthy roadcut also contains a basaltic dike that is not disrupted.

STOP 6. Popple (Poplar) Hill migmatite
Best exposure of Major Gneiss ih the northwest Adirondacks. A good introduction to problems of origin for migmatite and for the protolith of a widespread rock type in the Canadian Shield. This oligoclase-K-feldspar-quartz-biotite, sometimes sillimanite-garnet gneiss lies between the carbonate units and is traceable for more than 70 km from Philadelphia, New York, to Colton. It is consistently gray and fine-grained except where strewn with convolute quartzo-feldspathic veins, boudins, K-feldspar porphyroblasts, amphibolites and thick sill-like bodies of leucogneiss, all of which are visible at this outcrop. See the discussion for stop number 4 in Field Trip number 4, this guidebook. <br

7: GENERAL GEOLOGY OF THE ADIRONDACKS
Bradford B. VanDiver
S.U.N.Y. Potsdam

STOP 1. Fort Jackson gorge
For about a mile before Hopkinton on 11B, there are open views to the St. Lawrence Lowlands, that give the distinct impression of looking out to the sea over a gently sloping coastal plain. Here, at Fort Jackson, are some clues as to why. The well-bedded and strongly cross-bedded (Keeseville member?) Potsdam Sandstone dips gently northward away from the Adirondack Dome, presumably as a consequence of its geologically recent and ongoing uplift. The gentle slope "to the sea" apparently is the dip slope developed on the resistant Potsdam Sandstone. A few miles upstream in the Nicholville Gorge, the Nicholville Conglomerate rests directly on Precambrian gneisses, and represents either basal Potsdam or a sub-Potsdam unit.

STOP 2. Parking area 8 miles southeast of Santa Clara.
The bedrock cuts here are dark green, massive, syenitic, or mangeritic (pyroxene syenitic) gneiss, like those seen in passing Santa Clara and several more cuts to here. This peculiar rock-type is widely distributed in the Adirondacks, in association with anorthosite, charnockite (hypersthene granite) and various other members of the anorthosite clan. The large erratic boulders placed along the edge of the parking area display some of the other major rock types of the Adirondacks.
This is also a good place to view the low, knobby, glacially-scoured landscape of the foothills country. Extensive glacial polish and striae are visible in exposures about a quarter mile back from the parking area.

STOP 3. Gabriels, scenic camera stop.

STOP 4. High Falls Gorge.
This is a commercial tourist attraction located at the northeast end of Wilmington Notch, where the West Branch Ausable River drops over 100 feet. The river follows the Wilmington Notch fault zone and cascades over a resistant mass of granite (Figure 1). Numerous fractures in the gorge are intruded by diabase dikes that weather in recess. Dikes like these (and sills) are extremely common in the Adirondacks. Sixty-one "were recorded by W.J. Miller in his geologic study of the Lake Placid quadrangle (1919). Though definitely post-Grenville, their ages probably vary widely. Here, for example, they intrude fractures presumably related to the late Ordovician Taconic Orogeny. Elsewhere, as in the Lowlands Adirondacks, many are pre-Potsdam.
The rushing water has produced numerous potholes in the hard bedrock of the stream bed, some of very large size.
Similar features may also be seen in the Flume and adjacent roadcut about 2 miles farther east, where N.Y. 86 crosses over the river.

STOP 5. Whiteface summit
The rock of the summit is Whiteface-type metanorthosite. The Adirondack metanorthosite is a large, massif-type, anorthosite body of thick slab-like form that underlies most of the High Peaks region. Its igneous emplacement predates the Grenville Orogeny, and thus, it has been metamorphosed along with nearly all of the other Adirondack lithologies. Most of this large mass consists of a coarse-grained, porphyroclastic facies, called Marcy-type, in which plagioclase porphyroclasts commonly measure several inches in length, and rarely more than a foot. Whiteface lies near the northern border of the mass where, presumably, the shear and chill effects associated with emplacement are responsible for the finer grain size, more gneissic texture, and more gabbroic composition of the Whiteface-type (Figure 2). The structural and petrologic picture, however, maybe considerably more complex, as indicated by Crosby (1968), who considers the rocks here to be part of the Jay-Whiteface Nappe, and who has mapped complex interstratification of Marcy- and Whiteface-types with charnockite, mangerite, other gneisses below the summit. Figure 1 gives a highly generalized picture of the distribution of the major rock types around the mountain.
The effects of alpine glaciation are well represented on Whiteface by several aretes, cirques, and U-shaped valleys downslope from them (Figure 3). In historical perspective, Wisconsin glaciation at climax about 20,000 years ago, covered the Adirondack peaks with a thick blanket of ice. The ice thinned during glacial recession until the higher peaks projected through, but residual ice masses remained in the existing mountain valleys. The resulting alpine glaciers persisted for long enough to carve the distinctive features noted here and present throughout the High Peaks region. In the Catskill Mountains glacial cirques formed contemporaneously are much better developed, owing to the lesser resistance of the sedimentary rocks there, and to their nearly horizontal stratification.
The peculiar, ladder-shape of Lake Placid, and in fact, its very presence, demand further explanation. The lake occupies a system of crossvalleys developed first by stream erosion of fault zones, and then later deepened and widened by ice advance. It is now dammed at its southwestern end around Lake Placid village by moraine.
The role played by Wilmington Notch in pro-glacial lake development can best be appreciated in the view from the summit, From here, it is seen as a very narrow constriction between two large moderately-level lake plains. Figure 4 shows three stages of deglaciation in this region, with ice first blocking drainage through the Notch, and later melting away to permit convergence of the impounded waters on either side of it.
Other features to note from the summit are:
1) Lake Champlain in the distance opposite to the Lake Placid direction.
2) The profile of the High Peaks region in a sweep from southwest (across Lake Placid) to southeast (ca. 900 to left of Lake Placid).
3) Northeast-trending notches and valleys other than Wilmington Notch.
4) Slide stripes on steep, smooth cirque walls, on Whiteface, and on some of the other peaks.
5) Sheeting of the summit rocks.
6) Representative rock types in the retaining wall near the "Castle."

STOP 6. Glacial drift bank on Whiteface highway
This is a bouldery, sandy, well-washed deposit probably best described as a kame, but lacking visible stratification (concealed by slopewash?). Pick around among the fragments to see if you can find some Potsdam Sandstone. What would its presence mean in terms of glacial history?

8: GLACIAL GEOLOGY AND SOILS OF THE ST. LAWRENCE-ADIRONDACK LOWLANDS AND THE ADIRONDACK HIGHLANDS
Michael Kudish

8: GLACIAL GEOLOGY AND SOILS OF THE ST. LAWRENCE-ADIRONDACK LOWLANDS AND THE ADIRONDACK HIGHLANDS

Delta of the West Branch St. Regis River
Delta of the West Branch St. Regis River into Lake Iroquois at the 900-foot level. View of Parishville Desert (STOP 1) to the north (left) across the River.

STOP 1. PARISHVILLE DESERT
According to Van DIver (1976), this is a delta built into Postglacial Lake Iroquois by the West Branch St. Regis River at the 900- foot level. The delta is now deeply dissected, the Desert only a remnant. Much of the material (mostly fine sand) of the delta was probably carried south of Parishville by the ice sheet and then returned north by the River. Sand-blasted ventifact cobbles and boulders are Potsdam Sandstone, Adirondack Highlands gneisses, Canadian gneisses, and Bucks Bridge limestone (a dirty-brown, strongly-weathered part of the Theresa Formation).
Van Diver's hypothesis that upper soil layers have been removed by wind erosion is verified by digging a soil pit: the B2ir horizon is directly under the surface in places, the upper A horizons being absent.
A plantation of Scots (and a few Jack) Pines has provided the seed source for naturalized reproduction of these species. Other pioneers on the droughty, infertile soil are Gray and Paper Birches, Trembling aspen, White pine, Red maple, Fire cherry, Bracken fern, and Pilose Hair-cap moss.

Note the change in land use
Note the change in land use from existing farms to abandoned farms to forest in only several miles as we cllmb from the St. Lawrence Valley Lowlands to the Adirondack Highlands. The contact between the Potsdam sandstone and the Highlands gneisses is about two miles south of this intersection but concealed by thick glacial drift. Note also the pioneer vegetation on the abandoned farms. Aspens, Balsam poplar, Paper and Gray birches, Red cherry, Serviceberry, Meadowsweet, and White pine. Elevation 800 ft.

Cut in glacial outwash on left (northeast).

First cut in Adirondack Highlands rock.
The 1970 Geologic Map of New York identifies it as "amg," interlayered amphibolite and granitic, charnockitic, mangeritic or syenitic gneisses. Elevation 1060 feet.

Gravel pit in glacial till on left (north) and another pit 0.3 mile further.

Basswood trees in this area.
For this Adirondack rarity, see Figure 1. Basswood indicates rich, fertile soil in the Highlands. Elevation 1300 ft.

The falls are over "amg" just out of sight to the left (northwest).

amg rock cut on south (right). Elev. 1580 ft.

Gravel pit in till on left {north). Another pit at 32.8 miles total.

Several rock cuts in "phgs
Several rock cuts in "phgs" symbol on 1970 Geologic Map of New York. These are charnockitic, granitic, and quartz syenitic gneisses (see also Buddington, 1937).

Rock cut in phgs.
Shallow soils surround outcrops in the Highlands and often Red spruce and Hemlock predominate. On the deeper, well-drained till soils we have Northern Hardwoods (Beech, Yellow birch, Sugar maple).

A Balsam swamp.
Poorly-drained areas lacking Peat moss are dominated often by Fir.

Rock cut in phgs and a till cut at Mileage 36.0. Elevation 1650 feet.

Parking area. Note Northern Hardwoods.

Deep cut in glacial outwash.
At Total Mileage 39.9, the Town of Santa Clara is using another outwash mass for sanding roads in winter.

STOP 2. Black Spruce Bog
Elevation 1450ft. This extensive bog extends to Total Mileage 40.9; stop anywhere along its half-mile length. Note the resemblance to northern Canadian or Alaskan muskeg. Poorly-drained soils are classifled by the U.S. Soil Conservation Servlce as Histosols where at least 51 inches (1.3 m) of organic matter overlies the glacial drift or bedrock. All living plants and trees are fully rooted in the organic matter; no roots penetrate the mineral substrate. The dominant ground cover plants are the Peat mosses (Sphagnum spp.); when these mosses die, they accumulate, decay only partially, become compressed, and create extremely acid (pH 3 to 4) peaty soils. Most mineral nutrients are in limited supply so that the plants which grow here must survive on very low concentrations. A few of the plants have adapted to this environment by capturing insects as a nitrogen supplement (Sundews and Pitcher plants), while most others use mycorrhizal fungi to greatly extend the root absorption surface. Among the spruces in more open areas are Cranberries, Labrador Tea, Bog Laurel, Bog Rosemary, Leatherleaf, and Cottonfrass sedge. See Figure 2 •

First of a series of rock cuts extending for 0.6 miles.
The westerly cuts are in phgs but the easterly are in "hbg", biotite and/or hornblende granitic gneiss (Buddington, 1937).

Rock cut in phgs. Elevation 1645 feet.
From here for the next 4.7 miles, N.Y. 30 crosses a large, rolling outwash plain with numerous cuts and fills across kames, kettles, and crevasse fillings. Much of this area, called McColloms, was burned over in 1903 and earlier, and has been covered with pine plantations.

Rock cut in "a", Marcy Metanorthosite
Rock cut in "a", Marcy Metanorthosite (Buddington, 1953; Davis, 1971). Mountain Pond on the left (northeast) is bounded on the west by an esker and on the east by bedrock. Mountain Pond elevation 1634 ft.

Barnum Pond on the right (west).
Barnum Pond on the right (west). View of Jenkins and St. Regis Mountains beyond, the northwesternmost outposts of the Metanorthosite in the Adirondacks.

STOP 3A. Glacial Till
This cut is in glacial till with a loamy sand texture (average 88,% sand, 10,% silt, 2% clay), consisting mostly of crushed Metanorthosite, gneisses, and Potsdam Sandstone. It is often quite hard and dense, with silt grains cementing the sand and angular gravel fragments into a fragipan. The vegetation above this cut had been cleared for farmland and then was reforested both naturally and by people. The trees and plants you see here are pioneers: we must go to STOP 3B to see natural vegetation on a well-drained till site.

STOP 3B. Northern Hardwoods on Till
This road cut shows a typical soil profile developed in the upper 30 or so inches (0.75m) of well-drained glacial till. Soil can be defined as the zone of interaction between parent material (here till) and forest; it is only about 30 in. thick in most places as few roots penetrate deeper. Because of the sandy nature of the till, the soil which develops in it is characterized by rapid leaching (removal of organic matter and mineral material) from the upper or A horizons and deposition in the lower or B horizons. Such soil profiles developed in sands are very colorfully banded although infertile and are called Spodosols (formerly Podzols). The soil series here is Becket, a Typic Fragiorthod, family coarse-loamy, mixed, frigid. The C horizon is unaltered till in its original state, underlies the soil rather than is a part of it, and is not visible here without further excavation.
The forest which develops on well-drained tills such as Becket soils is a Northern Hardwoods Forest with Beech, Yellow Birch, and Sugar maple dominant. Walk up the old log road to the left (north) of the cut for a quarter of a mile or so to see this forest. Other trees are Striped maple, Hemlock, Red spruce, and perhaps Black cherry. See Figure 3.,
The elevation at the road cut is 1680 feet. Marcy Metanorthosite outcrops on the summit of 1863-foot nearby Beech Hill.
Common ground cover plants are Spinulose woodfern, Wood sorrel, Clinton's lily, Canada mayflower, Starflower, Wild sarsaparilla, and Purple trillium. Humus pH averages 4.5 to 4.,7 under Sugar maple.

STOP 4. Glacial Outwash
Park on the shoulder at the intersection of Route 30 and the Keese Mills Road which diverges to the right (west). Paul Smith's College Campus and Route 30's junction with Route 192 are adjacent. More extensive cuts in glacial outwash are present on campus and we can observe them if time permits. Elevation of junction of Routes 30 and 192 is 1658 feet. See Figure 4.
This cut is in glacial outwash with a sand texture averaging 96% sand, 3% silt and 1% clay. The deposit, made by a meltwater stream flowing to the southwest, consists of the same kinds of crushed rock as are found in the area tills, but with most of the silt and clay carried away in suspension. Due to the inadequate quantity of silt, sand and rounded gravel particles are not cemented together into a fragipan. Our Campus is built upon a series of kames as part of a valley train. Numerous dry kettles and kettle ponds are found locally. The thickness of the outwash valley train, as determined by water well data, ranges from zero at out- crops to over 165 feet (50.3 m): the average thickness on Campus is 60 to 100 feet (18.3 to 30.5 m). The valley train extends for 23.5 miles (38 km) southwest from Loon Lake to Fish Creek Ponds, with Paul Smiths about midway. The highest elevation of these sands at the College is between 1680 and 1700 feet so that any higher hills project above this sea of outwash as rock islands mantled with till. Taking isostatic rebound into effect, the original southwest slope of the train seems to have averaged about 5.8 feet per mile (Kudish,. 1975,1981).
The soil profile which develops on well-drained outwash sands is also a Spodosol. Because of the still coarser texture, the rate of leaching from the A horizons and the rate of accumulation in the B horizons are greater than in the tills. These out-wash soils, with less silt and clay, are even more infertile than their till counterparts. Drainage on the kames and other valley train features can be excessive and plants can wilt during long summer droughts. The sand grains of the B2ir horizon are often cemented by iron and aluminum sesquioxides (Fe2O3 and Al2O3},leached down from the gray A2 horizon above, creating a dense red-brown hard layer called an Ortstein. Just as fragipans occur locally only in tills, Ortsteins occur only locally on outwash. The critical concentration of silt appears to be about 6%.
The soil series here are Wallace (with Ortstein) and Adams (without); they are Typical Haplorthods, family sandy, mixed, frigid.
Climax vegetation on outwash consists of trees which can survive on nutrient-poor, drought-prone sands; the forest type is a mixed woods (mixed broadleaf and evergreen species) dominated by Red spruce, Yellow birch, Balsam fir, Red maple, and Hemlock. White pine follows disturbances and Red pine occurs on sites where wind exposure prevents other trees from surviving. Ground cover is very much like that on till soils, but humus pH is even more acid-- pH 4.0 commonly. Under the more open Red pine stands, commonly on the east shores of lakes, less shade-tolerant species occur: Blueberries, Huckleberry, Wintergreen, Trailing arbutus, Serviceberry, Sheep laurel and Bracken fern.

9: LOWER ORDOVICIAN STRATIGRAPHY AND SEDIMENTOLOGY, SOUTHWESTERN ST. LAWRENCE LOWLANDS
Bruce W. Selleck
Dept. of Geology, Colgate University, Hamilton, NY 13346
The Potsdam Sandstone and overlying Theresa Formation of the southwestern St. Lawrence Lowlands record the initial transgression of marine waters into the region during latest Cambrian to early Ordovician time (Fisher, 1977). The Potsdam Sandstone is widespread throughout the peripheral Adirondack region of northern and eastern New York, but is highly variable in thickness, composition and environments of deposition. In the area of this field trip (Figure 1), the Potsdam Sandstone (In this region, all of the Potsdam is referable to the Keeseville Member of the Potsdam Sandstone, Fisher, 1968, 1977.) can be subdivided into a lower and upper facies. The lower Potsdam consists dominantly of flat-bedded medium- to fine-grained quartz arenites with occasional cross-stratified units of varying scales. The lower facies lacks both body and trace fossils. A variety of red-pink coloration patterns are common in the lower Potsdam, making it a desirable building stone in northern New York. The lower Potsdam in this region is dominantly shallow marine in origin, but locally aeolian dune, beach and braided fluvial facies are present.
The upper portion of the Potsdam Sandstone consists of alternating burrowed and flat-bedded slightly calcareous sandstones deposited in a shallow subtidal to low tidal flat setting.
The overlying Theresa Formation consists of three informal subdivisions: lower Theresa thin-bedded calcareous siltstones of intrashelf lagoon origin; middle Theresa interbedded bioturbated dolomitic sandstones and cross-laminated quartz sandstones deposited in a shallow subtidal to low tidal flat environment; and upper Theresa sandy dolostones, dolomitic sandstones and calcareous siltstones of high tidal flat origin.
Biostratigraphically diagnostic macrofossils are absent throughout both formations in this area, although late Tremadocian conodonts have been reported from the Theresa-correlative March Formation in Ontario (Greggs and Bond, 1971). The extremely low faunal abundance and diversity may indicate that high and/or fluctuating salinities were prevalent in these shallow marine peritidal environments.
In the course of the trip, we will cross the so-called "Frontenac Axis", a region where Proterozoic rocks outcrop in a northwest-southeast trending belt, providing a connection in surface exposure between the Adirondack Lowlands and the Grenvillian Canadian Shield to the northwest. We will view the stratigraphic section in descending order as we drive southwest from Morristown to Alexandria Bay, New York, paralleling the St. Lawrence River. The Thousand Islands of this section of the St. Lawrence River are largely held up by Proterozoic gneisses and quartzites, although the larger islands (Wellsley, Grindstone) expose the mantling Potsdam Sandstone.

9: LOWER ORDOVICIAN STRATIGRAPHY AND SEDIMENTOLOGY, SOUTHWESTERN ST. LAWRENCE LOWLANDS

STOP 1. Roadcuts on both sides of Rt. 37
Roadcuts on both sides of Rt. 37 expose the high tidal flat facies of the upper Theresa Formation. The basal beds at this exposure consist of vuggy, sandy dolostones deposited as upper intertidal mudflats. A thin unit of laminated calcareous siltstone of tidal pond origin overlies the vuggy dolostone. The remainder of the section consists of dolomitic sandstones with abundant vertical and U-shaped burrows alternating with less bioturbated cross-laminated sandstones. These facies represent middle to high tidal flat sands. Quartz- and calcite-infilled voids in the sandy dolostone unit may document the former presence of evaporite (gypsum/anhydrite) nodules.

STOP 2. Middle portion of Theresa Formation
The rhythmic interbedding of yellow-white cross-laminated quartz sandstones and darker, bioturbated dolomitic sandstones is typical of this portion of the Theresa Formation. Rare mudcracks are present within the yellow-white sandstones. The dolomitic sandstones represent shallow subtidal to lower inter-tidal muddy sand flats that supported an abundant infauna. The yellow-white cross-laminated sandstones were deposited as slightly topographically higher mid-tidal flat sand bodies, upon which benthic fauna could not persist due to active current reworking and/or subaerial exposure to the substrate.
The sharp basal contacts of the bioturbated facies with underlying cross-laminated sandstones may indicate that the rhythmic alternation is due to a series of successive slight relative sea level rises of 2-3 meters. Thus, each bioturbated dolomitic sandstone-cross-laminated sandstone pair can be interpreted as a single shallowing upward sequence.
A peculiar "wavy-bedded" unit near the northeast end of the outcrops appears to have resulted from intraformational soft-sediment deformation. Note the general low-amplitude folding and small high-angle fault in the exposure.

Lower Theresa Formation and upper Potsdam Sandstone
Long roadcut exposing lower Theresa Formation and upper Potsdam Sandstone near Oak Point, New York.

STOP 3. Basal Theresa Formation and Uppermost Potsdam Sandstone.
The contact between the Potsdam Sandstone and lower Theresa Formation is prominently displayed at this stop and is marked by a color change (Potsdam = grey-white-yellow; Theresa = grey-brown), an abrupt increase in carbonate content in the basal Theresa, and changes in bedding style. The lower Theresa in this area consists of 2- 10 cm beds of plane-laminated or low angle cross-laminated calcareous fine sandstones/siltstones regularly interbedded with bioturbated calcareous fine sandstones/siltstones. Subvertical escape (?) burrows commonly traverse the plane-laminated beds and record attempts by deposit-feeding fauna to return to the sediment surface following a sudden influx of sediment. The environment of deposition of this basal Theresa facies is interpreted as a subtidal protected intrashelf lagoon characterized by sporadic periods of sediment influx (plane-laminated beds) followed by periods of quiescence of the substrate, allowing colonization by deposit feeders (bioturbated beds). This facies is limited in extent in the region, apparently because of the distribution of basement ridges of Proterozoic quartzite which acted as wave and current barriers. To the south and west of this area, coarser, bioturbated sandstones resembling those seen at STOP #2 occupy the basal Theresa Formation.
The upper Potsdam Sandstone at this top consists of a series of units of bioturbated calcareous medium-grained sandstones and plane-laminated to small-scale cross-laminated calcareous medium sandstones interbedded on a scale and style resembling the middle portion of the Theresa Formation seen at STOP #2. Alternating shallow subtidal (bioturbated sandstones) and low intertidal (plane-laminated to small-scale cross-laminated sandstones) environments are similarly inferred.
The interesting trace fossil Diplocraterion yoyo is ubiquitous in the Potsdam Sandstone here. The forms are generally indicative of a response to growth and/or erosion of the sediment surface. The generally vertical orientation of these and other burrows is typical of burrows found in modern settings where organisms live within the sediment for purposes of protection from wave and current violence or dessication. This burrow style contrasts strongly with the generally horizontal traces seen in the basal Theresa Formation. Fragments of the inarticulate brachiopod Lingulpis accuminata are common in both the upper Potsdam Sandstone and lower Theresa Formation at this stop.

STOP 4. Contact between the lower Potsdam and upper Potsdam
The contact between the lower Potsdam and upper Potsdam lithofacies is exposed at this road cut on the southwest side of Rt. 12. The lower portion of the outcrop consists of pink-yellow plane-bedded and crossbedded medium-fine sandstones typical of the lower Potsdam. The upper, massive calcareous sandstone bed is riddled with burrows, including Diplocraterion yoyo, and resembles some beds of the uppermost Potsdam seen at STOP 3. The bioturbated upper Potsdam is again interpreted as a shallow subtidal to low intertidal sand flat environment. The lower Potsdam here is likely a subtidal shelf sand, but the lack of burrows and other diagnostic primary structures preclude a definitive paleoenvironmental reconstruction.
Interestingly, the contact between these two lithofacies at this stop (and throughout this area) appears to represent a period of widespread emergence as documented by shrinkage cracks in the sandstones immediateLy below the contact and lenses of brecciated sandstones that are interpreted to result from breakup of a silcrete-like cemented soil horizon.
Glacially striated and chattermarked surfaces are observable on the northwest side of the road.

Beginning of series of excellent exposures of Proterozoic gneisses.

STOP 5. Proterozoic / Potsdam unconformity
The unconformity between the basal Potsdam Sandstone and underlying Proterozoic basement gneisses is exposed in this roadcut on the southeast side of Route 12. This contact represents a time interval of some 600 million years. The basal sandstones here exhibit large-scale low angle planar-tabular cross bedding, and are devoid of trace and body fossils. The depositional setting for this facies is problematic, although shallow marine tidal inlet, beach or aeolian dune environments are potentially workable facies models.
Considerable variation in color pattern is evident in the Potsdam Sandstone, with the basal 0.5-1.0 meters white to light grey in color, whereas the upper portion of the outcrop exhibits the pink, red, orange and salmon colors often seen in the Potsdam Sandstone used as a building stone. In this section, the deeply colored beds contain abundant tiny (2-50 micron) disseminated hematite and leucoxene crystals with these pigments both surrounding detrital quartz grains and imbedded in later authigenic silica cement. Highly corroded grains of detrital magnetite and ilmenite in the colored sandstones appear to have been the source of iron and titanium which subsequently precipitated as hematite (probably with a goethite precursor) and leucoxene under oxidizing diagenetic conditions. The white sandstones immediately above the unconformity contain no hematite or leucoxene, although limonite-goethite halos of relatively recent origin are locally developed around magnetite grains. The pristine condition of the majority of magnetite and ilmenite grains indicates that these basal sands never suffered a persistent oxidizing diagenetic history. The proximity of these unoxidized grains to the underlying pyritic gneisses suggests that the pore waters near the contact were "Eh-buffered" by the alteration of pyrite and Fe-silicates in the gneisses, thus preventing breakdown of the magnetite and ilmenite, and the subsequent precipitation of pigmenting agents.
Note that the sole surface of the lowermost sandstone bed mimics the shape of the underlying (now weathered) basement erosional surface.

STOP 6. Typical Lower Potsdam Sandstone
The roadcut on the southwest side of Route 12 exposes typical lower Potsdam Sandstone. Flat-bedded medium- to fine-grained sandstones underlie and overlie a 1 meter thick bed of tangentially cross-stratified medium sandstones. The dominant cross-bed dip direction is nearly due south. Immediately above the thick cross-stratified unit smaller-scale cross-beds dip to the north.
As with many exposures of the lower Potsdam Sandstone, assignment of an environment of deposition is difficult here. Although the flat-bedded sandstones lack trace or body fossils, a shallow marine subtidal environment is suggested by the continuity of individual beds, the lack of upward fining or coarsening trends and the lack of obvious channel form geometry. However, definitive diagnostic primary structures are absent. The large cross-stratified unit, produced by a bed form of at least 2-3 meters in amplitude (stoss-side erosion beveled the upper portion of the structure as it migrated, leaving behind a scoured lag deposit of granules at the up dip termination of the cross-strata), could have been deposited by a large subtidal sand wave, or an aeolian dune during a period of emergence.

STOP 7. Angular Proterozoic / basal Potsdam unconformity
STOP '7. The angular unconformity between the basal Potsdam Sandstone and Proterozoic gneisses is again exposed in these large roadcuts on both sides of N.Y.S. Route 12. The dominant facies present here is typical of the lower portion of the Potsdam throughout the southwestern St. Lawrence Lowlands. Flat-bedded medium- to fine-grained quartz arenites are occasionally interrupted by 0.2 to 1.0 meter sets of cross-strata. The lack of diagnostic trace and body fossils is a nettling problem if we assign a shallow marine environment of deposition to this facies.
Note the "weathered zone" at the unconformity. Does this represent a "regolith" or buried soil horizon: or is another explanation more viable? Note also the general absence of clasts of the underlying gneiss in the basal Potsdam Sandstone.

Donald B. Potter, Editor
Hamilton College
Clinton, New York 13323
Printed at Hamilton College for the New York State Geological Association. Additional copies may be obtained from the permanent Executive Secretary, Fred Wolff, Department of Geology, Hofstra University, Hempstead, NY 11550

AB2a: CROSS SECTION OF THE LOON POND SYNCLINE, TUPPER LAKE QUADRANGLE, NEW YORK
D. B. Potter, Jr.
Department of Forestry and Geology
University of the South
Sewanee, TN
This field trip crosses the Loon Pond Syncline, an area mapped during the summers of 1978, 1979, and 1980 under the direction of Leo Hall at the University of Massachusetts. The syncline, a northeast-trending elongate basin, was named and first mapped by Buddington and Leonard (1962) as the northeast part of the Bog River Synclinorium (Figure 1).
The syncline occupies most of the southern half of the fifteen minute upper Lake Quadrangle, which lies in the central Adirondacks within the Adirondack Highlands region. The Arab Mt. Anticline, composed of charnockitic gneisses, lies to the north, and the Salmon Lake Anticline lies to the south (Figure 1).
The stratigraphy of the syncline is distinctive. In contrast to most of the Adirondack Highland rocks which are chiefly orthogneisses and anorthosite, a great deal of quartzite, marble, and calc-silicate rock as well as quartzo-feldspathic gneisses constitute the rocks here. In this respect the rocks of the Loon Pond area are similar to those of the Northwest Lowlands (Figure 1). Erosion of the multiply deformed rocks has exposed a structural basin which shows some similarity to the Darning Needle Syncline in the Cranberry Lake Quadrangle (Leavell, 1977).
Access: Route 10, linked to Route 30 by Route IDA, extends west across the field area to the old Sabattis Railroad station and provides the primary access to the sparsely populated region (Figure 2). With the exception of a clear area south of Sabattis that burned in 1903, the region is heavily wooded. Topographic relief is about 800 feet.

AB2: CROSS SECTION OF THE LOON POND SYNCLINE, TUPPER LAKE QUADRANGLE, NEW YORK

View of Loon Pond Mountain to the northwest.

Small outcrops of East Charley Pond Gneiss on both sides the road.

Cross bridge at the head of Little Tupper Lake.

STOP 1. Otter Pond Dioritic Gneiss
Otter Pond Dioritic Gneiss is exposed along the north side of the road. Near the east end of the outcrop, a late 1 meter-thick vertical dike cuts the foliated gneiss. Discontinuous quartz veins help define the edges of the northtrending dioritic dike.
Estimated modes from thin sections of the foliated gneiss at this outcrop (646) and one .3 miles east (647) follow:
| 646 | 647
Quartz | 1 | 12
Plagioclase | 71 | 43
Biotite | - | 1
Augite | 13 | -
Hornblende | 10 | 36
Apatite | tr. | tr.
Zircon | 1 | tr.
Magnetite and Ilmenite | 4 | 8
Foliation is N84W,24SW and parallels foliation in basement rocks to the south. The outcrop was mapped by Buddington and Leonard (1962) as a diorite gneiss, but they did not consider the unit to be as widespread as is shown in Figure 2.

STOP 2. Sabattis Road Member of the Lost Pond Marble
The Sabattis Road Member of the Lost Pond Marble is exposed on the north side of the road. Most of the outcrop consists of brown-to gray-weathering marble beds up to 2 m thick. A few layers of quartzite, .5 m thick, are also present. The graphitic marble includes quartz, microcline, pale green diopside, phlogopite, calcite, sphene, and scapolite. The quartz and diopside stand out as small knobs and clusters on the weathered surface.
F2 fold axes plunge S45W at about 10 degrees, and minor undulations in bedding define a pronounced lineation in places.

STOP 3. Bear Pond Gneiss
The Bear Pond Gneiss is exposed along the northwest shore of Bear Pond. Layering and foliation strike northeast, parallel to the trend of the pond, and dip southeast beneath the Lost Pond Marble of STOP 2. Grain size in the magnetitebiotite-quartz-microcline gneiss varies from fine to pegmatitic.
A biotite-rich unit of the Bear Pond Gneiss lies on the north side of the road .1 mile west of Bear Pond. The gneiss is cut by a coarse microcline pegmatite body that is roughly concordant to foliation.
Near the crest of the hill .2 miles west of Bear Pond a third example of the Bear Pond Gneiss is exposed. The rock is a gneiss. Locally, both sillimanite and coarse garnet constitute more than 10% of the rock. A strong F2 sillimanite lineation plunges S46W at 4 degrees. Garnet distribution in this "chicken pox" rock is locally random, but in some places the garnet is concentrated in layers parallel to foliation.

Swamp to north is underlain by Lost Pond Marble.

Bear Pond Gneiss exposed on left side of road.

STOP 4. Bear Pond Gneiss
This area is not generally accessible to the public. Beginning at the southwest corner of the log landing, walk 400 yards at S40W across uneven terrain to the outlet of a small pond. Here the Bear Pond Gneiss is exposed in the axial region of a map-scale F2 syncline. Both limbs strike NE and dip SE. Many minor structures exposed along the outlet illustrate the second phase of deformation. Fold axes and mineral lineations form a tight southwest-plunging concentration on an equal area net. If water levels permit, a faint F3 magnetite lineation will be seen.
The Loon Pond Dioritic Gneiss is exposed on the other side of the outlet .1 mile southwest along the edge of the pond.

Bear Pond Gneiss on south side of road.

Abandoned Sabattis Railroad Station.
Turn around and return to Little Tupper Lake.

STOP 5. Overgrown quarry on west side of road.
The old quarry is in the Bog River Member of the Lost Pond Marble and contains graphite, calcite, sphere, phlogopite, quartz, calcite, and diopside. Diopside varies in color from pale to dark green and locally forms more than 50% of the rock. The rock is moderately well to poorly foliated, and grain size varies from medium to coarse. There is great variation in the relative proportions of calcite and quartz in the rock. Rocks at this location bear a strong resemblance to the diopsidic marbles of the Sabattis Road Member of the Lost Pond Marble (Stop 2).

AB2b: BEDROCK GEOLOGY OF THE GRAMPUS LAKE AREA, LONG LAKE QUADRANGLE, NEW YORK
Page Fallon
Department of Geology and Geography
University of Massachusetts
Amherst, MA
What follows is a brief description of the geology of the Grampus Lake area. These are the preliminary results of a study conducted under the guidance of Professor Leo M. Hall at the University of Massachusetts. The map area lies in the southwest part of the Long Lake quadrangle and includes a portion of the southeast corner of the Tupper Lake quadrangle (see Figure 1). Previous work in the area was done by Cushing (1907) in the Long Lake quadrangle and Buddington and Leonard (1962) in the Tupper Lake quadrangle.

AB2b: BEDROCK GEOLOGY OF THE GRAMPUS LAKE AREA, LONG LAKE QUADRANGLE, NEW YORK

STOP 1. Buck Mountain Fold Complex
This stop offers the opportunity to see the diopside augen quartz gneiss and other quartz rich gneisses and well exposed examples of second and third phase folds.
Road Cuts: Glassy quartzites and diopside augen quartz gneiss with small sparse diopside augen are exposed on the western side of Route 30. The small outcrop on the eastern side of the highway contains a few large dark green diopside porphyroblasts.
1-A.) Buck Mountain Syncline. Walk east from the highway 600 feet down the logging road. Bear left at a small cabin onto an overgrown skidder trail. Walk 1000 feet approximately N45E along a contour. The outcrop on the steep slope to the southeast exposes the hinge of the Buck Mountain Syncline, a large third phase fold, (see figs. 8 and 9). This is a tight fold which plunges moderately to the southeast on a northwest trending, steeply south dipping axial surface.
I-B.) Proceed west from the highway on an overgrown trail from the south end of the western road cut for about 1000 feet. Turn north and climb the hill to a large pavement outcrop.
The rock is typical diopside augen quartz gneiss. The augen which have weathered out, giving the rock this distinctive texture, are large single crystals or aggregates of smaller grains of green to white diopside. Scapolite is common. Minor K-feldspar, and traces of calcite, sphene, and zoisite are present.
A second phase isoclinal fold, outlined by a thin amphibolite, is refolded by a tight third phase fold, forming a hook interference pattern. Note the lack of an axial plane foliation in the hinge of the second phase fold. A more prominent axial plane feature is present in the hinges of third phase folds. Other folds, and a nice view to the south, are visible higher on the hill.

STOP 2. Rock Pond Syncline
The low outcrop to the left is a buff weathering diopside granulite which contains, in addition to diopside, calcite, plagioclase, and minor microperthite and quartz. Sulfides are present and graphite is abundant.
The structure of this area is poorly understood. The Rock Pond syncline closes around the calcsilicate gneisses just to the northwest. Refolding in the third phase produced north-side up folds (see fig. 4, Section E-F). The inappropriate rotation sense of the third phase fold is attributed to original curvature of the hinge line of the Rock Pond Syncline. Late folding about northwest trending axial surfaces causes local changes in the direction of plunge of the third phase fold.

AB2c: A TRAVERSE ACROSS THE SOUTHERN CONTACT OF THE MARCY ANORTHOSITE MASSIF, SANTANONI QUADRANGLE, NEW YORK
Paul Ollila
Poughkeepsie, NY 12601
The 15' Santanoni quadrangle is located between 44°00' and 44°15' north latitude and 74°00' and 74°15' west longitude in what is known as the High Peaks region of the Adirondack Mountains of New York State (Figure 1). The nearest towns of any size are Lake Placid, which is northeast of the quadrangle, and Saranac Lake, which is north of the quadrangle (Figure 2).
Approximately 80% of the quadrangle is underlain by anorthosite or anorthosite-related rocks. The remainder of the area is underlain by pyroxene syenite gneisses (commonly ascribed to a mangerite-charnockite series), amphibolites, granitic, pelitic and calc-silicate gneisses, marbles and quartzites. All of these rocks have been affected by the approximately one billion year old Grenville metamorphism and form the southeastern part of the Grenville province of the Canadian shield. Bedrock geologic mapping of the Santanoni quadrangle at a scale of 1:62 500 was carried out between 1978 and 1982 under the direction of Howard Jaffe from the University of Massachusetts.
AB-2

AB2c: A TRAVERSE ACROSS THE SOUTHERN CONTACT OF THE MARCY ANORTHOSITE MASSIF, SANTANONI QUADRANGLE, NEW YORK

STOP 1 Gooseberry Mountain Gneiss
The Gooseberry Mountain Gneiss consists of pink-weathering, medium-grained granitic gneiss, black-and white-weathering amphibolites that average 1 m in thickness and gray-weathering layers 1 to 3 mm thick rich in sillimanite, biotite and quartz. Sillimanite gneisses are the key to identifying the Gooseberry Mountain gneiss. Other rocks included within this unit are quite similar to rocks included in the Moose Mountain Gneiss.
Sillimanite gneisses form only a small part of the unit but have been found on the north side of Gooseberry Mountain, on the southern end of a hill just east of Deer Pond, and on the southwestern side of Gooseberry Mountain in the Long Lake quadrangle.
North of Gooseberry Mountain, zones characterized by abundant sillimanite rich layers occur within pink granite gneiss. Within these zones, sillimanite-rich layers are separated by 1 to 2 cm layers of quartz and pink microperthite augen. Granitic gneiss within the Gooseberry Mountain gneiss is typically composed of anhedral quartz, and microperthite, brown biotite, magnetite, and may contain green hornblende and orthopyroxene. Sample 17-1 (Table 1) is fairly representative except that the granitic gneisses commonly contain higher modal proportions of magnetite. Average grain size is 1 to 2 mm and foliation is defined by oriented biotite. Sillimanite rich layers and amphibolite layers parallel foliation. Both weathered and broken surfaces of granitic gneiss are pink to brown. Locally the granite gneiss is garnetiferous and garnetiferous granitic pegmatites are fairly abundant on the southwest side of Gooseberry Mountain.
Amphibolite layers are abundant at low elevations on the northern side of Gooseberry Mountain and also north of Deer Pond in the Long Lake quadrangle. The amphibolites are medium-grained but range in texture from well-foliated to granular. They are black-and white-weathering and typically have a color index near 50. Hornblende and plagioclase are the dominant minerals but amphibolites also contain brown biotite, orthopyroxene and oxides. Both garnetiferous and non-garnetiferous varieties have been observed. At location 17-22, granitic gneiss and amphibolite layers average 1 m in thickness and granitic gneiss forms about 60% of the outcrop. Going south from this location, the amount of amphibolite decreases, until near the summit of Gooseberry Mountain, the rock is almost entirely granitic gneiss. This sequence is reversed down the south side of Gooseberry Mountain. This repetition, and the occurrence of sillimanite gneisses on the north and south side of Gooseberry Mountain, suggest that this unit has been doubled by folding.

STOP 2 Moose Pond Formation-Ymp
The Moose Pond formation is extremely poorly exposed. One probably loose block of coarse-grained calcite marble (sample 17-6, Table 2) is located at the south end of Moose Pond. A mixture of rusty-brown medium-to-fine-grained diopside-quartz-microperthite granulites (17-7, Table 2) and fine-grained biotite-quartz-microperthite gneisses crops out along the western shore of Moose Pond at location 17-7. Although there is abundant quartzite and diopsidic quartzite float northwest of Shaw Pond a nearby outcrop northwest of Shaw Pond contains only a few thin diopside-rich layers. Most of the rock at this location is a medium-to fine-grained brown augite-biotite-quartz-plagioclase-microperthite gneiss.
No outcrops were observed in the region between Gooseberry Mountain and Wolf Pond Mountain. The Moose Pond marble is inferred to go through this region on the basis of topography and the geometry of folds in the Moose Mountain gneiss and the Gooseberry Mountain Gneiss. The aeromagnetic map (1978) shows a magnetic low east of Gooseberry Mountain which is consistent with the presence of marble in this valley. Mineral assemblages in rocks from the Moose Pond marble are listed in Table 2.

STOP 3 Calcareous Quartzites of the Moose Pond Formation.
These rocks contain quartz, diopside, calcite, sphene, microcline and scapolite. The scapolite is partially altered to prehnite.
The dominant foliation in these rocks trends 276°, 26 S and a strong lineation defined by trains of diopside trends 213°, 20°.
The rotation sense of minor folds at this outcrop indicates south side down movement.

STOP 4. Mylonitic pyroxene quartz syenite gneiss.
This rock is more intensely foliated and finer grained than normal for pyroxene quartz syenite gneiss. Foliation trends 90°, 35 S and locally a strong lineation defined by quartz ribbons trends 222°, 25°. A few asymmetric augen and what are possibly S and C foliations (Berthe et al. 1979, Simpson and Schmid, 1984) suggest south side down movement.
The mineralogy of pyroxene quartz syenite gneiss along Ermine Brook is typical of pyroxene quartz syenite gneiss found elsewhere in the quadrangle. Modes of typical pyroxene quartz syenite gneisses are listed in Table 3.

STOP 5 Gabbroic Anorthosite Gneiss (Ygag)
The gabbroic anorthosite, gneiss map unit trends NW-SE in a zone across the southwestern corner of the quadrangle (Figure 3). It lies between metamorphosed sedimentary and igneous rocks to the southwest and anorthosite to the northeast. The dominant rock type within the unit has a color index (C.I.) equivalent to gabbroic anorthosite but minor amounts of gneissic anorthosite, noritic anorthosite, gabbro, and syenite are included as well. Forty-four samples from the gabbroic anorthosite gneiss map unit were examined in index of refraction oils or in thin-section. Of these 27 have a C. I. equivalent to gabbroic anorthosite, 7 are monzonites, 5 are anorthosites, 2 are gabbros, 1 is noritic anorthosite and 1 is a quartz syenite. The syenitic rocks and the gabbros generally occur as concordant layers or sills. Most of the rock in the unit has a composition similar to gabbroic anorthosite except that it contains more garnet, hornblende, alkali feldspar and quartz. Modes of four samples of gabbroic anorthosite gneiss (Table 4) are representative of the amount of hornblende, garnet, K-feldspar, and quartz typically found in these rocks. Orthopyroxene, although present in all four modes, is not commonly present in anorthosite gneiss. At this locality pyroxene is commonly rimmed by hornblende which locally defines a strong lineation that trends 225°, 24°.
Rock at this locality is heterogeneous, consisting of gabbroic anorthosite gneiss with lesser amounts of gabbro, anorthosite, and syenitic gneiss. This is a good area to look at both intrusive relationships between the different rock types and the intense deformation typical of gabbroic anorthosite gneiss. Note also the different response of the various rock types to deformation.

STOP 6 Anorthosite.
This anorthosite is typical of anorthosite in much of the interior of massif. This rock is probably part of a layer or large xenolith of anorthosite in the gabbroic anorthosite gneiss map unit. More gabbroic anorthosite gneiss crops out to the north along the other branch of Ermine Brook and on Little Santanoni Mountain.

BC3: FORELAND BASIN SEDIMENTATION IN THE TRENTON GROUP OF CENTRAL NEW YORK
C. J. Mehrtens
Burlington, Vt. 05405
Purpose
The purpose of this field trip is to re-examine several of the well-known exposures of the Trenton Group in the Mohawk Valley. This re-examination is necessary due to the recent reinterpretations of the depo-tectonic setting and sedimentology of these units. Specifically, the Trenton Group in central New York has been redefined as a foreland basin and a tectonically active shelf edge/trench slope environment (Cisne, et al., 1982). The sedimentology of the Trenton Group has been shown (Mehrtens, in review) to evolve from in situ carbonates to dominantly turbiditic in nature. This field trip will visit several localities where participants will be able to view: (1) variations in the thickness of units over short lateral distances; (2) rapid facies changes within individual stratigraphic sequences; (3) syn-depositional slump fold horizons; (4) internal structures within limestone beds, identifiable as Bouma sequences. These features are all characteristic of sedimentation in the tectonically active foreland basin. The text for this field trip will review the stratigraphic model presented by Cisne and Rabe (1978) and Cisne, et al (1982). Evidence for the interpretation of the limestone and shale couplets of the Denley Limestone and Dolgeville Facies as bioclastic turbidites will also be reviewed. Previous interpretations of the Trenton Group depo-tectonic setting will be presented and compared to the foreland basin model. It is hoped that this field trip will demonstrate, if nothing else, the strong role that a model or paradigm can play in the interpretation of stratigraphic sequences.

BC3: FORELAND BASIN SEDIMENTATION IN THE TRENTON GROUP OF CENTRAL NEW YORK

Pass lower portion of City Brook on right.

STOP 1. Buttermilk Creek
Park immediately beyond the bridge and descend to Buttermilk Creek. The section downstream of the bridge is part of the Black River Group (Gull River), consisting of calcareous limestone. Underneath the bridge and a short distance upstream are ledges of coarsely crystalline limestone alternating with massive calcareous sandstone beds. These are the lagoonal sediments of the Napanee and Selby Limestones. These rocks have been described by Titus and Cameron (1976) and are characterized by their aphanitic texture, birdseye structures, massive bedding, and disseminated quartz sand. This facies continues in a series of benches going upstream. The contact of the Napanee and Selby with the Kings Falls occurs immediately above the pool below the first waterfall. The Kings Falls is differentiated from the underlying facies by the first appearance of fossiliferous calcarenites that are thinner bedded and exhibit lateral thickening and thinning of individual beds. The Kings Falls continues upstream to the larger waterfall, consisting of beds of calcarenite and bioturbated calcilutite. The lateral lensing of the beds, so characteristic of the Kings Falls is readily visible.
While at this stop you should: (1) examine the Napanee and Selby (lagoonal) facies as this is the only stop where they will be seen on this trip; (2) examine the Kings Falls, noting in particular the features which may suggest that it accumulated near wave base. Are there any internal structures within the limestone beds? How much shale, if any, is present? Are the beds laterally continuous? How frequent was bioturbation? Where are the fossils within limestone beds or on bedding planes?

STOP 2 City Brook
After disembarking from the cars, descend to City Brook upstream of the bridge. The section downstream is one of the most beautiful exposures of the Black River, Selby, Napanee and Kings Falls Limestones in the Mohawk Valley but is off limits. Under the bridge, and continuing up section, are small benches of the Sugar River Limestone. These bedding planes are distinguished by their abundant Prasopora colonies, along with the typical Sugar River benthic fauna described in Titus and Cameron (1976). Compare the Sugar River Limestone to the Kings Falls Limestone seen at STOP 1. How does it differ? What is the evidence that it might have accumulated at slightly deeper depths? How laterally continuous are these beds? Do they exhibit the same degree of lateral lensing? Is there a change in the relative percentage of calcarenite versus calcilutite beds? The contact of the Sugar River and the Denley Limestones occurs in the small waterfall. The basal Denley seen here is similar to the basal Denley seen at the next stop (Shedd Brook) but is very different than the basal Denley at Trenton Falls Gorge.
Here the Denley is much less fossiliferous and much finer-grained. Note the nodular limestone bedding. Bedding planes are not littered with fauna, except for an occasional trilobite and cephalopod. Continuing up the stepped benches note the abundance of calcilutite, mostly all barren. The dominant two lithologies of the Denley here are: (1) a barren calcilutite with planar bottoms and reworked (bioturbated) tops and (2) a nodular, more argillaceous calcilutite. These lithologies continue upstream until the waterfall is reached. Here, on the cliffs above the stream, the contact with the overlying Dolgeville Facies is seen. The Dolgeville is characterized by the interbedded planar calcilutite with thick interbeds of shale (see Figure 15). This City Brook section is interesting because it records a very rapid, nongradational facies change in the Sugar River/Denley contact. It also is unusual in that the Denley here is such a deep water deposit. Examination of the limestone beds reveals a dominance of planar laminations interpreted as Td and structureless, bioturbated micrite interpreted as Td'. While at this stop you should ponder the nature of the facies change from the Sugar River to Denley. Do you think it's the result of lateral facies mosaicing accompanying gradual transgression, or, could it be the result of a rapid drop of the fault block, drowning the shelf?

STOP 3. Shedd Brook
After parking at the top of the hill, cross the road and descend to the stream bed. Walk down to the base of the section. Exposed at the base of Shedd Brook is the upper Kings Falls Limestone. It should look similar to the upper part of the section at Buttermilk Creek, that is, coarse calcarenite to calcirudite beds which exhibit lensing. All of the Sugar River Limestone is exposed in this stream cut, and comparisons can be made between the Kings Falls and Sugar River. Study the Sugar River lithologies and bedding styles to draw some conclusion about environment of deposition relative to wave base. This is an important point because the Sugar River is interpreted to represent "normal" carbonate accumulation below wave base. If this is what "normal" below-wave base sedimentation looks like, what interpretations can be made about the overlying Denley Limestone? The contact of the Sugar River and the Denley Limestone occurs at the top of the waterfall. Examine the upper horizons of the Sugar River. Note the abundance of relatively unfossiliferous calcilutite beds with shale interbeds. How gradational are the Kings Falls to lower Sugar River to uppermost Sugar River facies? The top of the waterfall represents the last of the fossiliferous calcilutite and calcarenite beds in this section. The percentage of interbedded shale is also increasing. A bentonite horizon is present in the bushes on the left side of the stream. There is a long bench in the stream bed of the nodular barren calcilutite beds with thick shale interbeds of the Denley Limestone. This should look similar to the Denley seen at the previous stop. Up stream at the bend in the brook, Dolgeville beds of planar calcilutite and shale are seen. Passing under the road you continue to walk on nodular bedded, calcilutite horizons of the Denley Limestone. About 50 feet above the road on the right side of the stream, there is a small exposure of interbedded nodular calcilutite and planar calcilutite beds with bioturbated tops, also of the Denley Limestone. Two more bentonite horizons are located in this small cliff. The stratigraphic section seen along Shedd Brook is very similar to that in City Brook but it is worth walking this section to demonstrate: (1) the gradational Kings Falls to Sugar River section; (2) interbedded bentonite horizons.

West Canada Creek on right, access to Trenton Falls Gorge is ahead.

STOP 4. Prospect
(needs special permission from Niagara Mohawk Power Corp.)
After parking the cars across the bridge, descend the cliff to West Canada Creek carefully. Standing on the bedding plane above the creek, turn around and examine the cliff face. A prominent slump fold horizon is visible (Figure 16). Note that the slump fold can be traced laterally to an undisrupted horizon of calcarenite. The nose of the fold is characterized by brecciated clasts of limestone so the sediment was fairly lithified at the time of emplacement. Paleoslope measurements on this and other slope indicators (aligned fossils) indicate a paleoslope of S80E (Cisne and Rabe, 1978). Note the sediment in which the slumping occurred. This is the Denley Limestone, but a very different Denley than what has been seen at Stops 2 and 3. Note how fossiliferous some of the calcarenite and calcirudite beds are. The strophomenid Rafinesquina is especially abundant, as is Prasopora. Interbedded with this fossiliferous facies of the Denley are lithologies we have already seen: nodular, bioturbated calcilutite and calcilutite with planar bases and bioturbated tops (Td'). Also present are beds of graded skeletal debris (Ta), and horizontally laminated skeletal debris (Tb). Looking upstream a wide waterfall can be seen and individual beds can be traced across this exposure. Beds which exhibit this degree of lateral continuity, with negligible change in thickness could not have accumulated near wave base.

STOP 5. Dolgeville
This stop along East Canada Creek in Dolgeville is made for examination of the basinal shales. Parking on the hill and descending to the stream below the dam, the calcareous turbidites and interbedded shale horizons of the Utica shale are exposed. The calcareous turbidites are identifiable by their buff yellow weathering. Tc and Td horizons are the only Bouma Units present. The thick shale interbeds contain numerous good graptolites. Based on the Bouma Units present within the turbidite horizons and the thickness of the inter-turbidite deposits, it is possible to interpret this section as representing a distal turbidite facies. The source of the calcareous horizons is the foundered shelf (Dolgeville Facies) inter-tonguing with the basinal terrigenous muds. Continuing down to the pool at the base of the waterfall, drag folds associated with the Little Falls Fault are visible.

STOP 6. Canajoharie Creek
Descend to the creek from the parking lot. The creek bed is Chuctanunda Creek Dolostone of Lower Ordovician age. The lower cliff face contains the unconformity between this dolostone and the interbedded limestone and shales of the Kings Falls Limestone. Looking up the cliff the Kings Falls is overlain by the Canajoharie Shale (Figure 15). In other words, all of the Lower Trenton is missing, with the exception of a thin section (15 feet) of Kings Falls, and all of the upper Trenton is missing. Cameron (1971) described this section of limestone as Sugar River, but noted that it represents a shallower water environment than the Sugar River seen to the northwest (Stops 2 and 3). This unit can be better described not by the fossil assemblage it contains, but by the lithofacies present. The bedding style is identical to that of the Kings Falls seen earlier: laterally discontinuous beds exhibiting lensing and cross laminations. Looking at this section you can ask yourself: How can wave-reworked limestones and basinal shales be juxtaposed with no intervening deeper water limestones? Why are there no lower Trenton units between the Kings Falls and the Lower Ordovician dolomites? Do these abrupt facies changes represent lateral mosaicing produced by sea level changes or does it seem more probable that movement on a syndepositional block fault could generate this type of sequence?

STOP 7. Caroga Creek
After parking, descend to the creek below the bridge under Route 5. The section below the bridge and downstream are undifferentiated Black River deposits. Depending on the height of the stream, variable amounts of rock are exposed here. At low stage, aphanitic dolostones with birdseye structures are visible. The section between the two bridges has many covered intervals but ledges of coarsely crystalline limestone outcrop and are interpreted as Kings Falls. Under the second bridge ledges of laminated calcarenites outcrop, exhibiting planar tops and bottoms and lacking fossils. Upstream of these are beds of the bioturbated, barren calcilutites,. These last two lithologies are characteristic of the Denley Limestone as seen on City and Shedd Brooks.
A covered interval occurs above this and below the cliff with Utica Shale. This section then, is another thinned section of Trenton. Both the lower Trenton and upper Trenton units are missing or greatly reduced in thickness. Because the quality of this exposure is not equal to that at Canajoharie Creek, it is not as spectacular, but the significance of the facies changes is equally important. Note that as one progressed east for the last two outcrops, the magnitude of the variation in stratigraphic sections became more significant. This is in keeping with our moving further into the foreland basin from the stable shelf represented in the earlier outcrops.

BC4: ANIMAL-SEDIMENT RELATIONSHIPS IN MIDDLE ORDOVICIAN HABITATS
David W. Larson
Clinton, New York 13323
In recent years a number of workers have presented arguments to suggest that utilization of infaunal life strategies by marine organisms has varied through the Paleozoic. Evidence for a progressive "infaunalization" of Paleozoic communities comes from functional analysis of trace fossils (Seilacher, 1977), patterns of taxonomic richness of skeletonized bioturbating organisms (Thayer 1979, 1983), and the sedimentary record of the effects of burrowing organisms (Garrett, 1970; Sepkoski, 1982; Larson and Rhoads, 1983). Between the Middle Ordovician and Early Devonian, it seems that the depth of biogenic reworking of sediment in marine shelf settings increased from essentially zero to over 5 cm. Exploitation of buried food resources by deposit-feeders propels this infaunal invasion (Larson and Rhoads, 1983). Miller and Byers (1984) present an opposing view, that infauna are abundant and diverse throughout the early Paleozoic. At present, there is no consensus as to the style and degree of biogenic reworking in the early Paleozoic.
This field trip is meant to provide an opportunity to examine some of the evidence that has convinced me that biogenic reworking in Ordovician sedimentary environments was much reduced in comparison to recent counterparts. We will visit a series of four outcrops of Middle Ordovician carbonate rocks in the Black River Valley of northwestern New York (Figure 1). Our trip will take us on a transect of facies from the intertidal carbonates of the Black River Group through a range of shallow to deep shelf and basinal environments in the Trenton Group. The goal is to examine Ordovician animal-sediment relationships and their sedimentologic and paleoecologic implications.

BC4: ANIMAL-SEDIMENT RELATIONSHIPS IN MIDDLE ORDOVICIAN HABITATS

Bridge across Sugar River.
Upstream is an excellent exposure of the limestones in the lower portion of the Trenton Group. The quarry on the right side of the highway is in the Black River Group. Downstream, solution cavities and channels in the Black River Group cause subsurface drainage of Sugar River. At low discharge all of Sugar River disappears into the stream bed.

STOP 1. Road cuts in the Black River Group
Road cuts in the Black River Group on north and south side of Turin Road.
The Black River Group is a well documented example of tidally influenced carbonate deposition. This discussion of the stratigraphy and sedimentology of the Black River Group is largely drawn from Walker (1973) and Walker and Laporte (1970).
Here the Black River Group is divided into three formations:
Chaumont Formation: burrowed, fossiliferous wackestone.
Lowville Formation: fenestral, laminated mudstone, wackestone, and packstone.
Pamelia Formation: dolostone and dolomitic sandstone.
The sequence Pamelia/Lowville/Chaumont is interpreted by Walker (1973) to record the progressive transgression of the Middle Ordovician sea onto an eroded Grenville terrane. From base to top the Black River Group records the transition from supratidal to intertidal to shallow subtidal conditions.
The Lowville Formation includes a number of sedimentologic features indicative of an intertidal origin: mudcracks, fenestral fabric, and algal laminations. In addition, oolites, intraformational conglomerates, and fragmented mounds of Tetradium indicate vigorous stirring of the bottom.
The Chaumont Formation contains fewer sedimentologic criteria on which to base an environmental interpretation. Walker (1973) bases his assignment of the Chaumont to the shallow subtidal on the presence of brachiopods and bryozoa in the Chaumont and the interbedding of Lowville and Chaumont lithologies.
A striking feature of the outcrop is the contrast in sedimentary fabrics between the Lowville and Chaumont Formations. Burrows are rare in the Lowville. The sedimentary structures that permit such a straight-forward facies assignment are barely altered by biogenic reworking. Chaumont sedimentary fabrics on the other hand are dominated by burrows. In many cases the outlines of individual burrows are distinct; in others, the burrow outlines are diffuse. Importantly, other than laterally discontinuous bedding units, the biogenic structures have very nearly obliterated the depositional features. This style of bioturbation is characteristic of deposit-feeding communities (Rhoads and Young, 1970; also Rhoads and Boyer, 1982).
Here then we are able to see that for these Ordovician habitats, like their recent counterparts, the effects of bioturbation increase in an offshore direction. A deposit-feeding community was clearly active in this shallow subtidal setting.

STOP 2. Steuben Limestone of the Trenton Group.
Abandoned railroad cut through the Steuben Limestone of the Trenton Group. From this vantage point you can see the Tug Hill Plateau, underlain by the Utica Shale and Lorraine Group, to the west. To the east across the Black River Valley are Grenville rocks of the Adirondacks.
At this exposure we will examine a ten meter section of the Steuben Limestone (Figure 6). About 40 cm of Hillier Limestone is exposed at the top of this cut. We will see a much thicker section of the Hillier at Stop 4.
The Steuben Limestone is generally a thickly bedded fossiliferous packstone with some important variations in lithology. Near the base of the exposure, fossiliferous mudstones and wackestones are interbedded with centimeter thick argillaceous mudstones. Both grain size and bed thickness increases upward through the Steuben. Midway through the section are cross-laminated grainstones and packstones, some with mega-rippled upper bedding surfaces. There are shaly partings near the top of the Steuben, but no interbedded lime or argillaceous mudstones. The upper portions of the Steuben accumulated in more turbulent, more frequently agitated waters than the sediments at the base of the exposure. On the onshore-offshore gradient, I assign the Steuben to an open marine shelf subject to occasional stirring by currents or waves (Figure 3). Certainly the Steuben was deposited in a more exposed environment than the Chaumont of Stop 1.
Trace fossils are prominent throughout the Steuben. Near the base of the exposure are examples of Palaeophycus, Planolites, and Chondrites. These burrows are confined to bedding surfaces or generally penetrate the sediment only several cm. Monocraterion, a vertical sediment filled tube one cm in diameter and up to 8 cm long, is common in the crinoidal packstones near the top of the Steuben.
The style of bioturbation also varies vertically in the Steuben. Although nowhere is the Steuben completely burrow reworked, it seems that the greatest degree of biogenic alteration of the sedimentary fabric occurs in the upper Steuben with Monocraterion. This trend runs counter what we would expect from the modern: rather than finding the greatest degree of biogenic reworking in fine-grained sediments at depth, here the coarser-grained, shallow-water environments are more reworked. Consequently, at this point Figure 3 shows the divergence in bioturbation trends for the Recent and Ordovician.

STOP 3. Whittaker Falls Park.
Nearly all of the Trenton and Black River Groups are exposed along Roaring Brook. In a combination of rapids, falls, and level stretches, the rocks are exposed in both vertical section and on bedding planes. A long, nearly continuous exposure of the Denley Limestone is the focus of our attention.
On the basis of smaller grain size and fewer indications of turbulent conditions, I have assigned the Denley to a position further offshore than the overlying Steuben Limestone. The upper 50 m of the Denley contains mega-rippled and cross-stratified grainstones interbedded with finer-grained lithologies. This portion of the Denley was deposited within the reach of storm wave base. Because the basal 9 m of the Denley lack these grainstones, this portion of the formation appears to have accumulated below storm wave base.
The Denley Limestone contains a diverse fauna including brachiopods, bryozoa, crinoids, and trilobites. Many of the body fossils apparent on outcrop here are fragmented, abraded, and occur in grainstone or packstone units. Overturned heads of the bryozoan Prasopora attest to disturbance and relocation of many of the fossils. Figure 7 is an illustration of the role of turbulent events, major storms, in producing both the sedimentary structures and the fossil assemblages in the Denley.
Not all of the fossils are reworked, however. Adhering to the tops of limestone beds, or entombed within centimeter thick shaly partings are some fossil assemblages that indicate in place accumulation. Evidence for in place accumulation includes lack of abrasion and fragmentation and the co-occurrence of fossils ranging in size from .1 to 1.5 cm. In addition, several specimens of juvenile crinoids, complete with holdfast, suggest in place burial rather than transportation before burial.
Trace fossils are abundant here. Palaeophycus and Chondrites are the most conspicuous. Again, despite the presence of burrows, the sedimentary fabrics of the Denley retain their original features. Maximum depth of burrowing is about 3 cm.

Crummy roadcut on left is Steuben Limestone.

Excellent exposures of Trenton Group.

We are climbing to the top of the Tug Hill Plateau.

STOP 4. Bridge over Gulf Stream
Park off of road on left-hand side.
Cut along Gulf Stream where we can examine the contact between the Utica Shale and the underlying Hillier Limestone of the Trenton Group.
Watch out! Poison ivy is abundant and lush here, especially on the Utica Shale.
This is a 13 m section that records the transition from wave influenced shelf to deep, anaerobic basin (Figure 8). Illustrating this trend through the Hillier Limestone is a decrease in grain size, loss of mega-rippled and cross-laminated beds, and an increase in number and thickness of shaly partings in the limestone.
Here the transition to deeper water is marked by an increase in burrowing. Palaeophycus, Planolites, and Chondrites are present, but evidence of a bioturbating, deposit-feeding community is absent. Here, too, the conspicuous body fossils are brachiopods, bryozoa, and crinoids although the gastropod Liospira is locally abundant.
The uppermost Hillier is an interesting lithology with lumpy nodular bedding. The fauna here includes mostly phosphatic forms: trilobites, conularids, and lingulids with setae preserved around the margin of the valves.
The Utica Shale is a black, fissile, argillaceous mudstone. Careful collecting can turn up cephalopods, graptolites, and the trilobite Triarthrus.

BC5: SEDIMENTARY STRUCTURES AND PALEOENVIRONMENTAL ANALYSIS OF THE BERTIE FORMATION (UPPER SILURIAN, CAYUGAN SERIES) OF CENTRAL NY
Victor P. Tollerton, Jr. and Herman S. Muskatt
Utica College of Syracuse University
Utica, N.Y.
The Bertie Formation (Upper Silurian, Cayugan Series) of New York State, is world renowned for its spectacular eurypterid fossils. However, details of the total fauna (not just the eurypterids) and its significance, along with an understanding of the depositional environment, lags behind most other rock units in New York State. An understanding of the depositional environment of the Bertie is further complicated by a lack of published studies on the sedimentary structures that occur in the formation. Almost without exception, the fossils and the sedimentary structures have been treated as separate and totally unrelated aspects. Only minor attention had been paid to the structures (e.g., mud-cracks, and the windrow accumulations).
The writers are fully aware that the fossils are an important aspect in the overall interpretation of the depositional environment of the Bertie, especially when they are considered as primary sedimentary structures. Matters of identification and errors of stratigraphic relations of the fossils in the Bertie strata severely limit their usefulness and delay understanding of their significance (see further comments under Paleontology).
With regard to the sedimentary structures, we know of no published studies that list, describe, and discuss all of them. Buchwald (1963) did study some of them. The main purpose of this paper, then, is analyses of all of the known sedimentary structures of the Bertie, with emphasis on their use in the interpretation of the depositional environment.
Although only three stops will be made in the field, all are key outcrops. Stop 1 is at Forge Hollow, New York, where a complete sequence of the Bertie with both lower and upper contacts with the Camillus and Cobleskill Formations, respectively, are exposed. Stop 2 is at Jerusalem Hill, where the upper Fiddlers Green and the lower Scajaquada Members are exposed. Stop 3 is at Passage Gulf, where the lower contact with the Camillus is exposed.

BC5: SEDIMENTARY STRUCTURES AND PALEOENVIRONMENTAL ANALYSIS OF THE BERTIE FORMATION (UPPER SILURIAN, CAYUGAN SERIES) OF CENTRAL NY

Bridge over Oriskany Creek

STOP 1. Forge Hollow, New York
Outcrop on right. Big Creek on left. Parking on right.
On Route 315 (fig. 14) Oriskany Falls, N.Y., 7 1/2 minute topographic quadrangle
Rickard (1953) locality No. 43.
This locality is believed by Leutze (1959, p. 101- 102) to be the Waterville outcrop cited by Vanuxem (1982) and Hall (1859). Rickard (1953, 1962) designated this site as the type locality for his Forge Hollow Member (= Scajaquada Member of present terminology).
This is the only complete sequence of the Bertie Formation in east-central New York. Both the lower and upper contacts with the Camillus and Cobleskill Formations, respectively are exposed. The lower contact is at the southern end of the exposure.
Fossils collecting is highly discouraged during this field trip because of the dangerous conditions at this outcrop (e.g., blind curve, narrow road, steep outcrop). KEEP OFF THE ROAD.
Nearly all faunal and sedimentary structural elements discussed in this paper have been found by the writers or reported by others as occurring here. The purpose of this stop, then, is examination of the fossils and sedimentary structures, as well as their stratigraphic sequence.

Outwash Plain

STOP 2. Jerusalem Hill Rd. outcrop
Parking in lot of Town of Litchfield Town Hall, across from outcrop.
Jerusalem Hill, Litchfield, New York (fig. 15a) West Winfield, N.Y. 7 1/2 minute topographic quadrangle Lautze (1959) locality No. 207
This locality is the Litchfield outcrop cited by Vanuxem (1842) Hall (1859), Clarke and Ruedemann (1912), and Ruedemann (1925). The Wheelock Hill locality is located about 1 1/2 miles to the NW.
Although many eurypterids have been collected here in the past, NO collecting is authorized by the town board.
The purpose of this stop is to examine the geographic and stratigraphic continuity of the fossils and sedimentary structures with those seen at stop 1, located about 16 1/2 miles straight-line distance to the west of this stop.

Quarry on right. Camillus Formation
Quarry on right. Camillus Formation, 80 feet exposed. STOP: Depends on time. (Ref. Treesh, 1972. Stop III). Beckus Gulf. CAUTION, narrow road. Syracuse Formation, nearly complete section, (Treesh, 1972, Stop II).

Vernon Shale on right, (Treesh, 1972, Stop I)

STOP 3 Passage Gulf (Spohn Rd.).
Passage Gulf, on Spohn Road (fig. 15b). Millers Mills, N.Y. 7 1/4 minute topographic gradrangle
Rickard (1953) locality No. 39; Leutze (1959) locality No. 211.
This locality exposes an areally small outcrop, that is remarkably productive with regard to fossils. The upper-most beds of the Fiddlers Green Member are often excavated, giving the appearance of a battlefield.
The farmer who owns the land at this locality has recently bulldozed off the top layers of a portion of this site.
The entire Fiddlers Green Member is easily accessible for detailed examination of the sedimentary structures and their stratigraphic sequence.
The purpose of this stop is to examine the continued geographic and stratigraphic continuity of fossils and sedimentary structures with those seen at stop 1, located about 20 miles straight-line distance to the west of this stop. Also, discussion is encouraged at this last stop relative to epeiric sea environments and the Bertie Formation.

BC6: THE STERLING MINE. ANTWERP. NEW YORK A NEW LOOK AT AN OLD LOCALITY
S. C. Chamberlain
Institute for Sensory Research
Syracuse, NY 13210
The Sterling mine was the first American locality for the nickel sulfide, millerite. In the last hundred years it has produced many fine specimens of that mineral, including some that many regard to the the finest examples of the species ever found. In the past several years George Robinson at the National Museums of Canada and I have reexamined the geology, mineralogy, and origin of this landmark locality (Robinson and Chamberlain, 1984). Our interest was stimulated by our finding that much of the crystallized hematite in the ore had been reduced to magnetite and that some of the millerite had altered to the rather rare nickel silicate, pecoraite. The following pages summarize the history, geology, mineralogy, and paragenesis of this locality.

STOP 1. The Sterling Mine
The Sterling Mine is in Jefferson County, New York, along US Route 11 between Watertown and Gouverneur (Fig. 1). The water-filled open pit (Fig. 2) and surrounding dumps may be reached by foot via a farm lane which runs east from US Route 11 at a point 3.75 miles north of the intersections of Routes 11 and 26 in the village of Antwerp. The mine appears on contemporary topographic maps of the Antwerp Quadrangle as a small pond surrounded by low hills between Route 11 and Hawkins Creek. The property is owned by Mr. Raymond Villeneuve whose farm is 0.6 miles south of the entry lane on the east side of Route 11. Permission to collect must be secured before visiting the mine.

BC7: PLEISTOCENE GEOLOGY, GROUNDWATER, AND LAND USES OF THE TUG HILL, AND BRIDGEWATER FLATS AQUIFERS, ONEIDA COUNTY, NY: A CASE STUDY
Kenneth Jeffrey Goldstein
Environmental / Water Resource Planner
Oneida County Planning and Environmental Management Council
Utica, New York
No Road Log

B8: DEGLACIATION AND CORRELATION OF ICE MARGINS, APPALACHIAN PLATEAU, NEW YORK*
Dept. of Earth Sciences
Oneonta, NY 13820
Donald H. Cadwell
Geological Survey
New York State Museum
State Education Department Albany, NY 12230
The field trip area (Fig. 1) is located in the Susquehanna River Drainage Basin and includes parts of the Unadilla River, Wharton, Oaks, and Butternut Creek valleys. Local relief of the bedrock-drift interface reaches 1200 ft, while surface elevations range between 1050 and 2350 ft. The bedrock is predominantly Devonian sandstone, siltstone, shale (Hamilton Group) and limestone (Onondaga and Helderberg Groups). The purpose of this report, and associated field trip, is to establish and illustrate criteria for the recognition and correlation of ice margin positions in the upper Susquehanna River Drainage Basin.
This part of New York State was no doubt subjected to repeated glaciations during the Pleistocene Epoch. Multiple glaciations are suggested in the subsurface by interbedded diamictons (tills) and outwash gravels (Randall, 1972). However, the abundant glacial deposits within the field trip area formed during the advance and retreat of the Late Woodfordian ice sheet.
Six ice-marginal positions were held during Late Woodfordian time. They are, from south to north, the Wells Bridge, Oneonta, New Berlin, Cassville-Cooperstown, Middleburg, and Valley Heads ice margins. The Wells Bridge, Oneonta, and New Berlin ice margins were established during what is inferred to have been a semi-continuous retreat of the glacier. The glacier readvanced to form the Cassville-Cooperstown margin. The Middleburg ice margin developed during subsequent retreat from the Cassville-Cooperstown position. The final event within the field trip area was a glacial readvance that deposited the Valley Heads Moraine.
*Paper number 435 in the journal series of the New York State Science Service

B8: DEGLACIATION AND CORRELATION OF ICE MARGINS, APPALACHIAN PLATEAU, NEW YORK

Highway begins to climb valley wall behind Valley Heads Moraine

Hummocky crest of moraine on both sides of road

STOP 1. Ludlow Sand And Gravel Company
This gravel pit is located at the Valley Heads Moraine. Past exposures have illustrated the complex environments of deposition associated with this ice-marginal position.
F
Materials: well sorted, stratified sand, silt and clay; coarse cross bedded gravels; delta foreset gravels; laminated lake clay; poorly stratified fine sand; compact clay diamict (till).
Sedimentary structures: cross-bedding; channel lag gravels; cut and fill; large foreset beds; ripple drift laminations; slumped sands, gravels and silts.
Environment of deposition: Large(?) lake with meltwater streams of variable discharge, with deposition of gravels, sands and silts; near glacier terminus (possibly ice-contact) with deposition of sediments over blocks of glacier ice.
Noteworthy characteristics: ice-contact collapse features; thick, poorly stratified sands; well stratified, interbedded sands and gravels; channel cross bedding; delta foreset beds; compact clay layer with boulders concentrated at the base. This is diamict, deposited during an oscillation of the ice margin.

Segment of Valley Heads Moraine (on left and right)

On left (East) are ice contact, cross bedded outwash gravels.

Pitted outwash on right (West).

PICTURE STOP: "Smith Esker" on right.
This esker can be traced for almost a mile.

Cross Cedarville meltwater channel

Small gravel pit on right in outwash gravels

STOP 2. Hussey Quarry
This gravel pit contains a diamict (till) that documents the Cassville-Cooperstown readvance. The main things to see here are the stratigraphic units and the nature of their deformation.
There are three fundamental stratigraphic units exposed in the south wall of the quarry (see STOP 2 diagram). They are 1) a compact, fine-grained, matrix-supported gray diamict, which overlies 2) a tightly compact stratified drift containing fine gravels, interbedded coarse sands, and well sorted, highly distorted fine sands, and 3) a lower gravel unit containing well washed medium to coarse grained pebbles, cobbles and boulders. The compact stratified drift occurs as distorted lenses of cross-bedded sand and silt within the diamict. The lenses are upturned at their edges and contain distorted sand and silt and show thickening of each unit along fold axes. This thickening suggests that the sand and silt were NOT frozen during deformation. The underlying gravel is not well enough exposed to determine if it too is distorted.
The following questions must be addressed.
1. Origin of the compact stratified drift -
a. Were the sand and silt lenses sheared up from the lower outwash and included in the diamict by overriding ice movement?
b. Were the lenses deposited at the same time as the diamict?
c. Were the lenses deposited after the diamict and subsequently distorted by the diamict squeezing up and around them?
2. Causes of compaction and distortion -
a. Were the lens edges folded during emplacement through shearing?
b. Were the lenses deposited within the diamict with subsequent glacier overriding and deformation?
c. Were the lenses distorted during "dewatering" of the diamict?

Rt. 80 traverses hanging delta to Lake Cooperstown

Rt. 26 climbs up the kame and kettle topography
Rt. 26 climbs up the kame and kettle topography of the Cassville-Cooperstown Moraine (excellent view of moraine to the left)

PICTURE STOP

Esker on valley floor to the left, associated with ablation till

Esker complex on left

Entrance to New Lisbon Landfill - along New Berlin ice margin

Hill on left is the upvalley end of an esker

Additional eskers are seen down valley

Quarry in deltaic outwash
Entrance on left to quarry in deltaic outwash establishing a body of water in Butternut Creek valley at approximately 1150'

STOP 3. Morris Kame Quarry
In this quarry are exposed deposits typical of non-through valley deposition (stagnant ice blocks) and the associated conditions of glacier retreat. This kame and other landforms across the valley to the south depict an ice-contact environment dominated by local ponding and glacio-fluvial deposition.

Climb up the Aldrich Creek valley.
Turn left on Otsego Co. Rt. 49, which climbs up the Aldrich Creek valley. Aldrich Creek is an underfit stream occupying a valley that was enlarged by meltwater discharge along the New Berlin ice margin. Patches of discontinuous ablation till are found scattered along the valley.

House and outbuilding on the right are situated on ablation till

STOP 4. Divide Facies Of Ice-Marginal Deposits
This semi-active small quarry lies along the trend of the New Berlin ice margin. Typically, ice-marginal positions are correlated across divides by recognizing erosional features such as cols, meltwater channels or underfit streams. Here, however, is a rare view of the materials constituting a depositional landform, which resembles an ice-contact kame.
Unit | Thickness | Description
A | 36" - 48" | poorly sorted fine gravel, distorted in places
B | 24" - 30" | well stratified coarse sand, distorted by slump, collapse or injection from below
C | 6" - 12" | fine gravel with sand and silt matrix
D | 30" - 40" | compact diamict with clay matrix and striated cobbles
E | 36" - ? | washed gravels interbedded with a few layers of well sorted sand (few inches thick) which seems compact

Rt. 17 follows along the New Berlin ice margin
Rt. 17 follows along the New Berlin ice margin as it descends from the divide through the small hamlet of Cardtown and toward Pittsfield.

Kame moraine complex on the right
Kame moraine complex on the right is separated from valley wall by an outwash channel

Climb up back side of a kame moraine-outwash complex
Highway climbs up the back side of a kame moraine-outwash complex that swings across the valley marking a brief hesitation along the retreating New Berlin ice margin. Several similar complexes are found northward along Wharton Creek toward Edmeston.

Descend the pitted outwash surface
Rt. 80 descends the pitted outwash surface and follows the southern margin of a prominent dead-ice sink.

View of dead-ice sink on the right.

Another dead-ice sink can be seen on the valley floor at 2 o'clock

New Berlin valley train on left

STOP 5. New Berlin Gravel Quarry
The gravel quarry has been developed at two levels within a deltaic valley train. The upper level is primarily within the topset beds and the lower level (adjacent to Rt. 8) exposes massive foreset beds. Limestone and associated chert are major lithologic components constituting approximately 26% of all clasts (14% limestone, 12% chert). Postglacial leaching and reprecipitation of carbonates accounts for the various stages of induration found within some of the gravel units.
The topsets consist of 20 to 25 feet of moderately to poorly sorted, horizontal cobble gravels that contain some coarse sand lenses. Coarse lag gravels are common and depict a cut and fill origin. Crude channel cross bedding also is evident. Some of the sand lenses contain small-scale collapse features which are too small to have disturbed the associated gravel.
The underlying foreset beds are inclined at 28° to the southeast (S 30°-50° E) and generally consist of a finer pebbly gravel interbedded with sand. The gravel units consist of both well sorted, clast supported, matrix-free layers and sandy, pebbly fine gravel. The sand ranges from fine to coarse, with occasional silt layers up to 1 foot in thickness. No major collapse features or contorted beds were exposed in 1983.
This deposit is interpreted to be part of a massive deltaic valley train that was prograded down valley from the New Berlin ice margin (just .5 mile to the north) into an ice-contact lake. The dam was located 15 miles down valley in the vicinity of Mount Upton and Rockdale. The elevation of the dam corresponds to the topset-foreset contact elevation here. A major dead-ice sink marks the ice-marginal position at the head (upvalley extent) of the valley train. These depositional landforms and their association are helpful in recognizing the valley facies of ice-marginal positions.

Highway follows base of kame terrace scarp for the next 2.5 miles.
Kame terrace stands at 1300 ft. The kame terrace represents outwash shed along an ice margin that paralleled the Unadilla River valley, from New Berlin to Columbus Quarters. Associated kame moraines also occur along the valley, as at South Edmeston on the east side of the valley and Columbus Quarters on the west side. Late glacial discharge from the north (possibly associated with the Valley Heads readvance) dissected all of these ice-marginal landforms.

Highway climbs onto outwash associated with kame moraine

Kame-moraine complex to the right.

Highway descends north side of kame moraine
Highway descends north side of kame moraine, which is part of the New Berlin ice margin

Remnant of Cassville-Cooperstown Moraine
Breached and eroded remnant of Cassville-Cooperstown Moraine can be seen on the valley floor

Outwash plain forming the valley floor
Outwash plain forming the valley floor on the right developed from Valley Heads discharge originating from the north

Outwash surface on the right grades northward to Valley Heads
Outwash surface on the right grades northward to Valley Heads ice-marginal position near Cassville, 3 miles to the north

Characteristic hummocky topography
Road crosses characteristic hummocky topography of Cassville-Cooperstown Moraine for about one mile

Road crosses trend of Valley Heads Moraine
Road crosses trend of Valley Heads Moraine, which is not well expressed in the topography here.

BC9: SEDIMENTOLOGY AND FAUNAL ASSEMBLAGES IN THE HAMILTON GROUP OF CENTRAL NEW YORK
Bruce W. Selleck and Robert M. Linsley
Hamilton, NY 13346
The Middle Devonian (Givetian) Hamilton Group in Central New York State consists of approximately 1600 ft. (approximately 490 meters) of richly fossiliferous interbedded shales, siltstones and sandstones. During Givetian time, the central New York region lay to the west (present geography) of the Appalachian mobile belt. The sediments derived from this orogen were transported to the west and northwest into an epicratonic foreland basin. Other studies (Brett et al., 1983; Baird, 1979) suggest that deposition in western New York took place on a topographically subdued bottom. Regionally, paleoslope was SW-directed, but local swells and depressions of 20-100 km wave length were present (Baird, 1979). In the region of this study, the Hamilton has been the subject of numerous paleontological studies, from the pioneering work of James Hall through the biostratigraphic studies of Cooper (1930, 1933). More recently, the integration of paleontological data and detailed sedimentologic/stratigraphic studies have resulted in the development of depositional/paleoecological models (e.g. Brett et al., 1983). The purpose of this trip is to introduce participants to the varied faunas and lithofacies of the Hamilton and to document the cyclic arrangement of faunas and facies. It is this cyclicity that provides us with a key to understanding the sedimentological evolution of the Hamilton Group.

BC9: SEDIMENTOLOGY AND FAUNAL ASSEMBLAGES IN THE HAMILTON GROUP OF CENTRAL NEW YORK

Active limestone quarry on eastern valley wall.
Low hills in center of valley are part of the Munnsville kame-moraine complex. On the eastern valley wall, an active limestone quarry in the Helderberg Group and Lower Onondaga Limestone is visible.

Outcrops of Upper Helderberg Group and basal Onondaga Limestone (Edgecliff Member) on right.

Outcrop of Seneca Member on right.

Outcrops of Cherry Valley Limestone on right.

STOP 1. Chittenango Shale-Member of Marcellus Fm
Roadcut on left.
Stratigraphy/Sedimentology.
This roadcut exposes a typical section of the black silty shales that dominate the lower Marcellus Formation. Fissile, organic-rich silty shales record deposition on an anaerobic/clearly marine substrate. The extreme limitation of oxygenation and bottom circulation during deposition of this facies suggests that the waters of the basin may have been stratified in a manner analogous to the modern Black Sea. Large carbonate-cemented concretions are well-exposed mid-way up the outcrop face, and clearly demonstrate that pre-compaction cementation occurred. Note that the laminae in the silty shales are deformed by compaction around the concretions. Septarian fractures in the concretions have yielded finely crystalline dolomite, calcite and barite. Note that the surfaces of some concretions appear to have preserved burro and steinkerns of gastropods. Is there a linkage between the presence of the burrows/fossils and the formation of the concretions?
The fauna at this stop is exceedingly limited, dominated by Styliolina with occasional specimens of Nowakia, Leiorhychus and "Euryzone". The styliolinids and Nowakia occur abundantly on particular bedding planes that occur sporadically throughout the section. It is presumed that these are planktonic forms for they are occasionally found in almost all of the lithologies of the Hamilton Group, including the apparently inhospitable environment suggested by these non-bioturbated black shales. It has recently been persuasively argued (Yochelson, in press) that Styliolina is not a mollusk, and although he did not assign it to any other higher taxon, we are persuaded that it is safest to assume that it is not a member of an extant phylum, and Fisher's assignment to the Cricocondarida seems as sound as any. Nowakia occurs much more rarely (about 1% of the fauna), but is found with the styliolines and presumably shares a similar mode of life even though taxonomically it is a tentaculitid rather than a styliolinid.
Leiorhychus and "Euryzone" are not usually found in association on the same bedding plane as Styliolina, but scattered throughout the section. Two very different interpretations have been placed on the paleoecology of these genera. It has been suggested that "Euryzone" could have had a mode of life similar to the extant genus Ianthina, which builds a bubble raft to which it clings until it bumps into its prey, the Portuguese Man-of-War, Porcellia. It has similarly been suggested that perhaps Leiorhychus was attached by its pedicle to floating pieces of wood. These interpretations thus attribute the occurrence of these genera to being introduced from outside the immediate environment. However, since both species are restricted to the black shale environment of the Hamilton we suspect that they are indeed adapted to maintaining a marginal existence in an environment that is an abomination to other faunal elements.
(Note: we have placed quotation marks around "Euryzone" because we have never seen a specimen that was determinable below the ordinal level of Archaeogastropoda. Other members of the genus Euryzone are associated with reef deposits and the anomalous environment of the Hamilton form suggests that it is probably not appropriately assigned to this genus.)

STOP 2. Bridgewater and Solsville Members of Marcellus Formation.
The basal section of the exposure here consists of dark, fissile to blocky silty shales which bear a rather limited fauna. The section coarsens upward, corresponding with gradual increase in faunal diversity. The basal portion of the Solsville Member is difficult to access at this stop, but a fair selection of typical Solsville forms can be found in talus mid-way up the exposure.
The preservation of the fossils at this locality is quite exceptional. Thin sections of the material shows that growth lines are well preserved, suggesting that the calcitic shells preserved here are probably original material. Some aragonite is still preserved, but most has been altered to calcite. Still even the mollusks exhibit good growth lines which suggests that the replacement of aragonite is a very precise molecule for molecule substitution.
This unit is also the site of some rather rare and unusual fossils including the monoplacophoran Cyrtolites and the bellerophont Praematarotropis and soft bodied preservation of annelids (Cameron, 1967).
The fauna is dominated by the brachiopods Spinocyrtia in the upper sandier facies, and Mucrospirifer in the middle siltier layers, along with the bivalves, Ptychopteria flabellum, Gosseletia triquetra, and a variety of nuculids, gastropods including Bembexia sulcomarginata and Palaeozygopleura hamiltoniae plus a variety of orthoconic cephalopods.
One unusual aspect of the preservation in this quarry is the fact that a very large percentage of the bivalves are preserved with both valves intact. This is no surprise for nuculids which are infaunal and typically are entombed in the sediments which prevents their valves from gaping open upon death. However, for bysally attached semi-infaunal forms like Gosseletia, mobile semi-infaunal forms like Grammysia and epifaunal genera like Ptychopteria, it is unexpected to find both valves intact. It would seem possible that quick burial may have been an intermittent, but relatively common cause of death in this assemblage. This interpretation is also consistent with the rather large escape burrows that are abundant in this unit.
Many faunal elements in this unit are restricted to single bedding planes that may repeat throughout the quarry. For example, Palaeozygopleura has been found on only three horizons, but within those horizons they may be very abundant. The axis of coiling of the shells of Palaeozygopleura in this quarry are randomly oriented allowing us to infer that they have not been aligned by current action. Yet twice as many are found in an aperture down position as in an aperture up position. Since all positions of this shell exhibit equal hydrodynamic stability, we infer that the shells were occupied at the time of death, and the orientation of the shells reflects the life position.
Other bedding planes are dominated by Bembexia sulcomarginata, a pleurotomarian which was probably an algae grazer or possibly a deposit feeder. Many of the shells of Bembexia in this unit are encrusted with a trepostomatous bryozoan (Leptotrypella). Most frequently it is the upper surface of Bembexia that is encrusted, though some specimens exhibit encrustation of the base while the spire remains clean. Very rarely is a specimen found in which the encrustation spreads very far from one side onto the other.
We suspect that encrustation primarily developed on dead shells on Bembexia. Bembexia is a genus that is only found in the Marcellus and Skaneateles Formations of the Hamilton Group while Palaeozygopleura is found throughout.

STOP 3. Basal Moscow Formation.
This quarry exposes the "interior portion" of a upward-coarsening cycle of the Hamilton Group and can be generalized as consisting of an upper sandy facies dominated by bivalves and a lower silty facies dominated by brachiopods. Separating the two facies is a thin coquina consisting predominantly of the shells of Spinocyrtia granulosa.
The upper sandy unit is dominated by large epi-byssate bivalves and large semi-infaunal bivalves as well as larger spiriferoid brachiopods. There are also occasional specimens of the burrowing trilobite Trimerus (Dipleura) deKayi and large specimens of Phacops rana.
The lower silty portion of dominated by brachiopods, particularly Chonetes, Devonochonetes, Athyris Rhipidomella, and Mucrospirifer. Bivalves are also abundant, commonly infaunal nuculids or mobile semi-infaunal forms (such as Grammysia). The dominant trilobites in this facies are Greenops and smaller specimens of Phacops. Gastropods are represented by Glyptotomaria and Ruedemannia, the bellerophont Retispira and Palaeozygopleura. Bembexia drops out of the fauna after the Skaneateles. However, the Palaeozygopleura shells in this quarry are barely recognizable for the shells are completely encrusted by the trepostomate bryozoan Leptotrypella. The aperture is always open, but the shell is completely encrusted all the way around which is quite surprising since Palaeozygopleura is a shell dragger, incapable of lifting its shell from the substrate. This leads us to conclude that either Leptotrypella was capable of extending its colony down into the sediment (which no modern bryozoan can do) or that there was a secondary occupant (a sipinculid?) of the dead Palaeozygopleura shell that was capable of elevating the shell off of the substrate so that the bryozoan could establish itself everywhere except the aperture. In some individuals the encrustations became much thicker on one side of the shell than the other, always the adapertural side is thickened, which leads us to believe that the secondary occupant is still occupying the shell, but the mass of bryozans has forced him to resort to a shell dragging mode, thus killing the bryozoans on the apertural side of the colony.
There are also massive colonies of other trepostomatous bryozans in the lower part of the quarry.

STOP 4. Geer Road - Quarry
Stratigraphically and faunally this locality is similar to STOP 3. The faunal elements are essentially as described for the previous locality. Some of the rarer elements of the fauna of both quarries include Hyolithes, occasionally with helens and operculum in place, and two different phyllocarids with their bivalved cephalothorax and segmented abdomen with the telson composed of three spike-like projections.
A prominent surface near the basal portion of the section exposes a phosphate pebble bed containing abundant brachiopods and rare fish plates.

STOP 5. Roadside Quarry and rubble: Mottville Member of Skaneateles Fm.
Roadside Quarry and rubble: Mottville Member of Skaneateles Fm. Sedimentology:
The exposure at this stop nicely exhibits the shaley siltstone-to-sandstone transition of the Mottville Member. The lowermost portion of the outcrop consists of relatively fissile to blocky shaley siltstones dominated by small brachiopods. The section coarsens rapidly upward to silty, fine-grained sandstones which exhibit some cross-lamination and rare hummocky bedding.
This stop is dominated by the higher energy faunal elements that characterize the silty sandstones of the Hamilton Group. These include the large epifaunal byssate pectinoid bivalves including Glyptodesma, Leiopteria, Pterinopecten, Actinopteria and Limoptera as well as semi-infaunal bivalves such as Grammysia. The typical trilobite of the unit is the large burrowing trilobite Trimerus, whose punctate carapace comprises one of the dominant skeletal elements of this locality. Complete specimens are fairly common, most commonly not enrolled and not infrequently oriented on edge or on end as some other unusual position relative to the sediments. It is suggestive that the area was occasionally subjected to events, which involved rapid burial. Other common elements include the brachiopods Spinocyrtia, Mucrospirifer, Camarotoec and Devonoproductus. The gastropods are not well preserved here, but include Bembexia and Palaeozygopleura.

C10: THE LATE WISCONSINAN GLACIATION OF THE WEST CANADA CREEK VALLEY
Jack C. Ridge
Dept. of Geology
David A. Franzi
Lafayette College
Easton, PA
This field trip focuses on the glacial stratigraphy of the West Canada Valley and the interpretation of the Late Wisconsinan history of the region. The Late Wisconsinan stratigraphic record in the West Canada Creek Valley (Figure 1) is unique in central New York in terms of its completeness and in the complexity of the glacial events that it represents. The significance of such lithostratigraphic documentation of the glacial record is underscored by the lack of success in developing a regional glacial chronology based on morphostratigraphic relationships (Coates, 1976; Calkin and others, 1982). Correlations based solely on morphologic evidence are often ambiguous due to the time transgressive and composite nature of many glacial landforms. The glacial deposits of the West Canada Creek Valley provide an important lithostratigraphic basis for correlations to the well-developed time-stratigraphic and geologic-climate classifications in the eastern Great Lakes Region (Dreimanis and Karrow, 1972; Dreimanis and Goldthwait, 1973).
The West Canada Creek Valley is an area where the sedimentology of readvance deposits and relative chronology of simultaneous readvances from several different ice flow directions may be studied. Ice from the Ontario Lobe (Black River and Oneida Sublobes) and the Hudson-Champlain Lobe (Mohawk Sublobe) as well as Adirondack through flow and possible Adirondack ice cap sources encroached on this region during the Late Wisconsinan (inset on Figure 1).
The field trip is designed to give an introduction to as many of the glacial stratigraphic units as possible and to show their sedimentologic diversity. It can in no way, however, show all the stratigraphic relationships which were used to determine the glacial history of the region. This would require too many stops for a one day excursion. In addition, many exposures that would be more informative than those shown on this trip are not readily accessible or are inappropriate for a group of this size. Important localities which are not included as stops on the field trip are discussed in the text.

C10: THE LATE WISCONSINAN GLACIATION OF THE WEST CANADA CREEK VALLEY

Kast Bridge.
The course of West Canada Creek has been straightened in this section of the valley. Note the flat topped bluff on east bank of West Canada Creek.

Holland Patent and Norway tills
Bluffs on left side of highway (to west) expose Holland Patent and Norway tills. North Creek enters West Canada Creek from the east. West Canada till and striations on bedrock of the Trenton Group (N60W) are exposed along the last mile of North Creek before it enters West Canada Creek.

Bluffs on east bank of West Canada Creek
Bluffs on east bank of West Canada Creek expose units from Holland Patent till at the top through Norway and Hawthorne tills to West Canada till at the base. The bluffs are typical of many high banks along West Canada Creek between Kast Bridge and Middleville. These bluffs do not exist on the west bank of West Canada Creek because of the asymmetry of the bedrock profile of the valley. The apparent flat-topped surfaces of the bluffs are capped by till and lacustrine sediments. The flat benches may be the result of initial fluvial downcutting in the valley or the floors of lakes that existed during recession of the Barneveld Readvance.

View of STOP 1 from KOA campground.
Bluff on east bank of West Canada Creek (Section 9 on Figure 3). Ahead on left are commercial Herkimer "diamond" (more appropriately Middleville "diamond") prospecting grounds.

Exposures of Little Falls Dolostone on left while entering town of Middleville.

STOP 1. West Canada Creek bluff exposure.
Park vehicles on shoulder of Rt. 169 next to entrance to pasture on right. Walk on dirt road to right to top of hill and across pastures for 0.5 miles to West Canada Creek bluff exposure.
Features and topics for discussion: (Section 9 on Figure 3)
1) Lithology and genesis of unit equivalent to the Norway till.
2) Lithologic and provenance changes within lacustrine sediment between the Norway till equivalent and the Hawthorne till.
3) Nature of contact of Hawthorne till and upper Newport beds.
4) Transition from upper Newport beds to West Canada till.
5) Compact and stony character of West Canada till.
6) Paleomagnetic samples were taken from the upper Newport beds and from three levels within the lacustrine sediments between the Norway till equivalent and the Hawthorne till.

Terrace along West Canada Creek.
Many terraces in the valley are graded to lake levels in the lower West Canada and Mohawk valleys (Figure 13). They contain alluvial fan sediment and slope away from large gullies cut in the glacial deposits along the valley sides.

Outcrops of Little Falls Dolostone
Right side or Rt. 28 and continuing for the next l.5 miles are outcrops of Little Falls Dolostone. Behind the exposure on the right is a large quarry noted for its Herkimer "diamonds".

STOP 2. White Creek
Park vehicles and walk across pasture on west side of White Creek Road.
Features and topics for discussion: (Section 5 on Figure 3)
1) Upper Newport beds appear at top of bluffs in soil profile.
2) Clayey and silty character of West Canada till.
3) Deformation of lower Newport beds beneath West Canada till. Nappe-like folds and thrusts with northwest directed displacement.
4) Transition from lower Newport beds to White Creek till and associated sediment flows.
5) Topography on the upper surface of the White Creek till (morainic or drumlinoid features or neither?).
6) Very stony character of the White Creek till which contains a high proportion of metamorphic clasts.
7) Subglacial grooving on the surface of the White Creek till has been exposed here in the past.

Large bluff on the west bank of West Canada Creek
In view to the west-southwest from this intersection is a large bluff on the west bank of West Canada Creek (Section 6 on Figure 3). This section contains all the units from the lower Newport beds to the Norway till on top.

Hawthorne till overlying upper Newport beds
Right side or highway. Bluff exposure of Hawthorne till overlying upper Newport beds.

Old meander scar of West Canada Creek.
Right side of highway. Across pasture are bluff and gully exposures (Sections 3 and 4 on Figure 3) which contain all units from basal White Creek till up thru Norway till.

Lacustrine sands
Right side of highway. Lacustrine sands which lie stratigraphically below the Norway till and may predate or be time-equivalent to the Hawthorne till and Salisbury Readvance

Fluvial terrace on right
Fluvial terrace on right is inset in an older alluvial fan which slopes toward the center of the valley from large gullies to the northeast.

STOP 3. Poland sand and clay pits.
Two exposures:
1) pit exposing outwash sands. Fluvial sand infilling early incision of the valley cut during fall in lake levels proceeding the Barneveld Readvance.
2) Clay Pit exposure of Phase II sediments.
Section: (similar to Sections 1 and 2 on Figure 3 and northwest end of West Canada Valley profile on Figure 7)
(top) |
6 ft. | oxidized varves (soil profile)
1 ft. | sediment flows
6 ft. | clayey dark gray till with high proportions of sandstone and Trenton Group limestone clasts (Norway till)
1 ft. | deformed lacustrine beds
4 ft. | thin varve couplets (less than 2 inches) containing a pink and tan clay component and red rain-out sediment (Oneida Sublobe provenance); flutes indicate paleocurrent flow to the southeast.
12 ft. | thick varve couplets (greater than 2 inches) with dark gray and drab colors and black rain-out sediment near base (Mohawk Sublobe provenance); couplets thicken downward; rib and furrow structures indicate paleocurrent flow to the northwest.
2 ft. | lacustrine sand and silt, oxidized at top and contain calcareous cement
25 ft. | rippled lacustrine sands with calcareous cemented layers and lenses; paleocurrent flow to the east
| (limit of exposure)
Note especially change from Mohawk to Oneida Sublobe provenance within the varve section accompanied by a change in paleocurrent directions from northwest to southeast.

Ice-marginal delta at the maximum position of the Barneveld Readvance.
Flat-topped hill to right with gravel pit excavations is capped by an ice-marginal delta at the maximum position of the Barneveld Readvance.

STOP 4. Cincinnati Creek sections (Figure 5).

Incised portion of a delta
The highway crosses an incised portion of a delta deposited during recession from the Hinckley Readvance.

Hinckley Moraine System
Hills on both sides of the highway are a part of the Hinckley Moraine System.

Exposure on the east side of the road
Exposure on the east side of the road contains calcareous western provenance gravel overlying older non-calcareous gravel of Adirondack provenance.

STOP 5. Dirt driveway leading to Trail's End bluff
Dirt driveway leading to Trail's End bluff exposure on Hinckley Reservoir (Figure 10). NOTE: This is private property.

STOP 6. Balley Hills delta.

Hummocky topography
On both sides of the road is hummocky topography resulting from stagnation of the Black River Sub lobe as it thinned over the Black River-West Canada Creek divide during recession from the Hinckley Readvance. The drift is composed of both stratified deposits and ablation till.

C11: STRUCTURE AND ROCK FABRIC WITHIN THE CENTRAL AND SOUTHERN ADIRONDACKS
2011: This following trips are identical:

C11: STRUCTURE AND ROCK FABRIC WITHIN THE CENTRAL AND SOUTHERN ADIRONDACKS

C12: GROUNDWATER CONTAMINATION FROM A SANITARY LANDFILL: INVESTIGATIONS, REMEDIAL ACTION AND ENERGY RECOVERY AS A POSSIBLE SOLUTION
Kenneth Jeffrey Goldstein
Environmental / Water Resource Planner
Oneida County Planning and Environmental Management Council
Utica, New York
PURPOSE
The purpose of this field trip is to view the adverse impacts resulting from the improper disposal of solid and hazardous wastes. A tour of the Rome Sanitary Landfill will reveal the impacts on the environment resulting from hazardous waste landfill leachate. Leachate can be seen at the landfill and in nearby streams. The participants will be able to view the remedial measures being conducted at the site, including, the construction of a barrier cap, gas vents and monitoring wells. A discussion on the elements of the site investigation and remedial actions utilized will be conducted while touring the facility. Questions are encouraged! Later in the day the participants will tour the Oneida County Energy Recovery Facility in Rome, N.Y. This facility, which will not be operational at the time of the field trip, is one of Oneida County's solutions to the land burial of industrial and municipal solid waste. Although the facility will not be operational, all equipment will be on-line and will be reviewed.

C13: SEISMICITY IN THE CENTRAL ADIRONDACKS WITH EMPHASIS ON THE GOODNOW, 10/7/84 EPICENTRAL ZONE AND ITS GEOLOGY
Lamont-Doherty Geological Observatory
of Columbia University
Palisades, New York, 10964

Richard H. Lindemann, Editor
Department of Geology Skidmore College
Saratoga Springs, N.Y.

A1: A TRIP TO THE TACONIC PROBLEM AND BACK
PHILIP C. HEWITT
Department of the Earth Sciences
SUNY College at Brockport
Brockport, NY 14420
The purpose of this paper is to provide background information needed for both the full-day trip (A1) and the half-day trip (B1). The full day trip involves data from the entire paper while the half-day trip concentrates on the Taconic Problem primarily. However, to understand either day fully, the entire paper must be read. A separate Road Log for each trip is provided at the end of the paper.
The paper describes geologic features to be examined in area from Saratoga Springs, N.Y. to Manchester, Vt. A discussion and overview of the Taconic region and the "Taconic Problem" will be presented. Consideration will be given to both the sequential and fault hypotheses proposed for the High Taconic region.
The Taconic region is subdivided into the High Taconics and the Low Taconics based on the extreme difference in relief. The High Taconics are the mountains of Vermont, west of the Vermont Valley, with elevations of approximately 3000-4000 ft. The Low Taconics are the hills primarily in New York, west of the High Taconics, with elevations up to approximately 1500 ft. (Hewitt, 1961a). Lithologic and other distinctions will become apparent in the later discussion.

A1: A TRIP TO THE TACONIC PROBLEM AND BACK

STOP 1. The Springs, Tufa Terrace, And Flat-Lying Snake Hill Shale
The Spring along the pathway is typical of the mineralized and carbonated springs in the region. Do taste the water but with caution. Firstly, the water at this Spring passes through the dark shale and therefore, contains iron and sulfur. The amount of sufur is sufficient to "surprise" the unwary. Secondly, the water contains the radioactive gas radon. Thirdly, the bedrock from which the water rises is a dolostone and in addition to the calcium it contains magnesium. Therefore, this water is an excellent laxative. "A word to the wise is sufficient."
All of the springs are the result of the expansion, along the faults, of carbon dioxide gas released by the weathering of dolomite at depth. Acid water percolates downward to the dolostone, weathers the rock and forms mineralized water plus gas. As the water reaches the faults the carbon dioxide gas expands with the reduction of pressure and the gas carries the water to the surface.
The "Island Spouter" is, of course, not truly a geyser. In this case it is gas within a constricting pipe which allows the water to spurt into the air.
Walk north approximately 500 ft. along the path. Note dark gray to black flat-lying shale. Approximate equivalents to these shales (Snake Hill, Canajoharie?) will be seen later as metamorphic rock. These shales are medial Ordovician in age.
Note the Tufa Terrace. Formed of colloidal and precipitated calcium carbonate from the Spring on the hill above (west) the terrace. Here leaves and insect fossils are formed each year as the organic material is trapped, coated and then permineralized with the calcium carbonate.

Sand dunes.
Some totally and partially exhumed. Probably from Lake Albany equivalent. Note long axes to west. Possible 5 minute "extra" stop here if time permits.

View of Taconics ahead (east).

Saratoga National Monument on right.
Battle of Saratoga took place here during Revolutionary War.

STOP 2. Stark's Knob Area. Folded, Distorted Shale
Note badly distorted black shale on right side of road. These are equivalent of those at Stop 1 (Snake Hill). This is part of Logan's Zone and the rocks are faulted, badly fractured and somewhat metamorphosed. Note limestone and dolostone pebbles (gray to blue-gray) in shale and oxidation of parts of shale surfaces. Limestone and dolostones are not indigenous to this locality. They are from the area far to the east. We will see these later in the day in situ. The red oxidized zone probably represents a "baked" zone as the area moved westward during faulting. The "baking" might also have resulted from the emplacement of the basaltic pillow lavas of which Stark's Knob is composed.
Walk uphill and to the right for a quick examination of Stark's Knob.
This is a flow of basalt (now pillow basalt) which apparently formed when lava flowed into the sea and across a shaly (or muddy) shoreline with fragments of limestone and dolostone present. The lava and the shale which enclosed it were later thrust westward during the faulting which produced Logan's Zone. We will see basic material similar to this lava but as dikes on Rt. 7 in Vermont. Stark's Knob was formerly used as road metal.
The basalt and the shale are both of medial Ordovician age. Return to cars.

Note folded black shales on right side of road along route.

STOP 3. Folded Wallomsac Formation
This outcrop exposes typical black slate and metamorphosed sandstone (now quartzite) of the Walloomsac formation. Strata here are strongly folded and thrust faulted. Cleavage is readily visible. There is some mineralization along the faults. Folds of various magnitudes may be observed here. This outcrop expresses well the folding in the Low Taconics. Virtually every bed is slickensided. Some folds show evidence of refolding.
No fossils have been found to verify the age of this outcrop. However, it maps well into the Walloomsac which is generally considered to be medial Ordovician (Trentonian) in age. It is probably correlative with the Snake Hill. However, lithologically it resembles the Austin Glen member of the Normanskill formation more closely. This unit is believed to be older than the Snake Hill but still medial Ordovician.

Black slates and phyllites on both sides of roads.
Black slates and phyllites on both sides of roads. These are visible in many locations along the road.

STOP 4. Green Slate And Black Slate Outcrop
Green slate (or phyllite) is exposed on the left (northwest) side of the road. Black slate (or phyllite) lies across the road on the southeast side. The decision as to whether these are slates or phyllites is rather subjective since they appear to border both lithologies. Beds appear to dip to the southeast which is common in the area. The green slates appear to lie under the black beds. The age of the black phyllites is probably medial Ordovician since they are on strike with the Walloomsac beds. If so, they lie above green beds which, in many ways, resemble those of the beds further east in the High Taconics. The green slates are also on strike with known Cambrian beds of the Mettawee slates (the famous purple and green slates) in the Taconic sequence. Some few purple beds are seen at this locality also but they are better exposed 1.6 miles northeast along Rt. 313. Purple and green Mettawee slates are well known in the northwest part of the Equinox quadrangle. The author considers the green slates to be Cambrian Mettawee formation and the black slates to be Walloomsac. In this case a major unconformity is present. This is probably the unconformity recognized by MacFadyen (1956), Thompson (1959) and others. Return to cars. Continue on Rt. 313 to northeast.

Interfolded black and green slates.

Purple and green slates.

Tight folding, chevron folds in green phyllite
Tight folding, chevron folds in green phyllite (Mt. Anthony fm.) in Vermont. On left (north). These are the same phyllites which lie over the carbonate in the High Taconics. Since crossing the State Line into Vermont, we have been in the High Taconics.

STOP 5. Ordovician Carbonate Outcrop
Covered Bridge on right (south) and dolomitic marble outcrop on left (north) Pull to right past Covered Bridge and park.
This outcrop of medial Ordovician gray to blue-gray dolomitic marble contains many fossil fragments (crinoid, cystoid and related groups) and a few remains of a Trentonian cephalopod (probably Endoceras proteiforme). This establishes these strata as medial Ordovician in age. Although these beds resemble closely the Bascom-Beldens (undifferentiated), the age is too young. The Bascom-Beldens is generally considered to be of early Ordovician age. Therefore, these fossiliferous middle Ordovician rocks were mapped separately and with the associated black phyllite as the lower Mt. Anthony formation (Hewitt, 1961a). If the upper part of the Beldens could be demonstrated to be Trentonian (medial Ordovician) these beds could easily be placed, on purely lithologic grounds in that formation.
The strata at this outcrop directly underlie the green phyllites of the High Taconics assigned to the Mt. Anthony formation (MacFadyen, 1956). It is the nature of the contact between these units that is the crux of the present Taconic problem (see paper preceding this Road Log for details). Some evidence of that contact will be seen at a later stop and more definitive evidence is presented at Stop 2 of the Road Log for the trip entitled "The Nature of the eastern Taconic Contact."
Although some observers may conclude that the folding at this locality is not extreme, it should be noted that green phyllite probably lies below the surface as well as above the carbonate. Many of the beds are upside down and generally the outcrop is an inverted section at road level. Further up the hill above (north) the road the strata are right-side-up.
Some sandy beds show cross-bedding that helps to establish this but the extreme overturning of these folds will be very apparent as the field trip progresses. The nature of the synclinorium actually requires this as our eastward travel will demonstrate. Please return to the cars and drive east, staying on Rt. 313. Note carbonate on drive eastward. We will examine these later.

This is the west side of the Vermont Valley.
Outcrops within the Valley are Cambro-Ordovician Valley sequence strata. On right (east) are the Green Mtns. of Precambrian to earliest Cambrian age.

View of Mt. Equinox ahead.

Delta deposit on left (west) from post-glacial lake (Lake Bennington?).

STOP 6. Mt. Equinox
No mileages will be provided for the drive up Mt. Equinox since easily recognizeable stopping places have been provided. Drive carefully both up and down the mountain! If you do not have faith in your car's brakes and transmission do not attempt the drive. The drive will test your car.
The road up starts gently in the Shelburn formation with a lower member (Sutherland Falls) of creamy to white calcitic marble, a middle (Intermediate dolomite) member and an upper Columbian marble, the commercial marble of the Vermont Marble Belt. None of this formation is exposed until the first bench or terrace is reached. Elsewhere on the mountain, excellent exposures of all three members are easily observed.
Park at the Parking Lot at the first terrace. This is our lunch stop. Rest rooms are opposite the Parking Lot about 300 ft. to the south. Enjoy the view but please keep the area clean.
Before returning to the cars, gather at the picnic tables for a discussion of the geology, history and culture of the mountain. If time permits we will visit a small marble quarry about 900 ft. north of the Parking Lot at an elevation 100 ft. lower than the Parking Lot. You may collect at this quarry. Return to cars and continue drive up the mountain. Do not stop on the road but note when green phyllite first appears. This occurs after first private road on your right (northeast). Continue climb.
Park at Parking Lot on second terrace. This locality is in the green phyllite. It provides excellent samples of the phyllite, pyrite cubes, and pseudomorphs of limonite (goethite) after pyrite, particularly in the northwest part of the exposure. Collect all you want. Return to cars and continue climb.
At first flat area, note Little Equinox Mtn. on right (southeast) and Lake Madelaine on left (west). Note also areas of landslides on right (east) side of sharp turns near top of Mt. Equinox. One of these will be climbed on foot on the trip discussing "The Nature of the eastern Taconic Contact".
At the summit, park but leave car engine running at fast idle for a few minutes before shutting down. This will help cool the engine. Gather in Parking Lot for orientation, geomorphology and overview of Taconic area.
Descend mountain. Keep car in LOW GEAR while descending. Brakes have been known to fade and even burn on descent. Stop at first flat area below summit for view of Lake Madelaine and monastery. Lake Madelaine is totally artificial. That area was formerly Big Spruce Swamp. Continue to base of mountain. Stay in LOW GEAR.

Note Cook Hollow on left (west).
White flat outcrop is Table Rock composed of white marble (Columbian?), Landslide Scar visible above Table Rock. This is carbonate-green phyllite eastern Taconic contact. Hewitt (1961a) concludes that this is a gradational contact.

STOP 7. Dolomite Outcrop. Basic Dikes
This is the Winooski dolostone of medial Cambrian age. Bedding and jointing permit blocks to fall easily so caution is important here. Note basic dikes in wall of exposure near north end.

STOP 8. Overturned Fold
This structure is a classic fold in the Bascom-Beldens formation. The lithology is dolomitic marble and the folding is typical Taconic folding. BE CAUTIOUS AT THIS OUTCROP. FOLLOW DIRECTIONS OF THOSE DIRECTING TRAFFIC. THEY ARE THERE FOR YOUR PROTECTION.

STOP 9. Carbonate-Green Phyllite Contact
Turn left (northwest) over one lane bridge. Corkscrew turn in folded Mt. Anthony formation. Drive through turn and turn at next intersection and reverse direction. Park at end (southeast) of large outcrop.
The green phyllite (Mt. Anthony formation of MacFadyen (1956)) is well exposed here. Intense folding is obvious. These are small folds on successively larger folds in this area. With care, small folds may be collected here. All of this section appears on first glance to be green phyllite. However, at the southeast corner of the last outcrop on this road the application of cold, dilute hydrochloric acid results in effervescence at the base. It is impossible visually to locate the horizon at which calcium carbonate ends and the phyllite begins. Only an acid reaction or lack of it can determine the difference. Is there a fault here or not? It is up to you to decide. Note the valley to the south. Is this a depression within the phyllite or the result of solution of a carbonate? No outcrops have been located within that depression but plentiful float is found there.

A2: THRUSTS, MELANGES, FOLDED THRUSTS AND DUPLEXES IN THE TACONIC FORELAND
WILLIAM BOSWORTH
Marathon International Oil Company P.O. Box 3128
Houston, Texas 77253
WILLIAM S. F. KIDD
S.U.N.Y of Albany
Albany, New York 12222

A2: THRUSTS, MELANGES, FOLDED THRUSTS AND DUPLEXES IN THE TACONIC FORELAND

STOP 1A. Potsdam Formation
Quartzites, arenites and dolomitic micrites of the Potsdam Formation (medial Cambrian). Williams Street in Whitehall.
Grenville gneisses are exposed in the riverbed directly below this outcrop; although the unconformity is not exposed here, it is elsewhere along strike north and south. The main purpose of this stop is to see that the strata in this outcrop show no prominent signs of deformation, being part of a gently east-dipping regional homocline. Although not a main focus of this field trip, the evidence for both shallow marine to beach facies (prominently cross-bedded and rippled clean arenites and quartzites) and lagoonal supratidalflat facies (dolomitized micrites and thin shales, laminated in places with small stromatolites and locally with sand-filled vertical burrows) are well displayed here. Some layers, with pebbles of dolomitized micrite, may well be storm deposits.

STOP 1B. Limestones of the Whitehall Formation (late Cambrian).
Sciota Road 1.6 miles from Whitehall. These strata also are part of the regional gently east-dipping homocline of autochthonous shelf strata (typically 5-10 degrees east dip). No folds or cleavage are visible in these strata, and oolites which are locally abundant in some beds do not appear strained to any significant extent. Stylolites do occur in some beds but they are bedding-parallel, presumably compactional in origin. Laminated algal micrites, locally stromatolitic, can be seen, along with micrite edgewise breccias with oolites, all evidence of shallow marine to intertidal/supratidal facies. Nodular chert layers occur locally in this outcrop. It should be emphasized that most of the volume of the pre-medial Ordovician autochthonous shelf sequence is dolostone. Limestones form an overall small proportion and this unit (part of the Whitehall Formation) is, after the medial Ordovician limestones, the most prominent limestone in the early Paleozoic shelf sequence. Dolostones occur at the east end of the quarry where the outcrop nears the road - we will not examine these.

STOP 2. Thrust of limestones over shaley melange.
Thrust of medial Ordovician Isle la Motte (or Middlebury) limestones over medial Ordovician shaly melange. Locality indicated with an "X" on Fig. 2.
Carbonate exposures such as this one form lenticular belts bounded by medial Ordovician shales and finegrained wackes (flysch) in a zone near this vicinity a few kilometers wide between the western edge of the Taconic Allochthon and the eastern edge of gently east-dipping, unfolded strata that rest with intact unconformable relationship on crystalline Grenville basement (such as those exposed at Stops la and b).
Where contacts are exposed, such as here, and Stops 6 and 9, evidence for faulted lower contacts of limestone over shale are seen. In particular, the underside of the limestone is coated with fibrous vein-type slickensides, the lineation plunging close to down-dip. Truncation of stratification in the limestone is seen locally. An abundance of veins in the limestone within about 50cm of the thrust surface suggests hydrofracturing and high fluid pressures during thrusting. A crude, lenticular cleavage in the underlying shales is deflected adjacent to the fault surface. A small horse of shale, isolated above the main thrust surface by a duplex mechanism , can be seen approximately half way along the exposure of the. thrust (Fig. 3). Towards the western limit of the overlying carbonate sheet a detached sliver of carbonate about a meter long lies in the cleaved shale just below the prominent fault surface. This may be a structurally detached piece or (less likely because of its shape) an olistolith. Similar lozenge-shaped pieces of medium-grained graywacke up to about 1/2 m long occur sparingly in the phacoidally-cleaved shale in the western part of the cut. Slickensided surfaces suggest that they too are products of structural disruption ("structural slicing"), although an olistolithic origin cannot be discounted. The shale and siltstone is locally bedded, with minor folds in part of the outcrop. Most is pervasively disrupted by the phacoidal cleavage whose microstructural character, with abundant evidence for shear offsets, is clearly related to faulting (Bosworth and Vollmer, 1981; Bosworth, 1982, 1984). This carbonate and other exposures like it are shown on the New York State geological map and by Fisher (1985) as giant olistolithic blocks. We find this interpretation of the outcrops to be unconvincing and prefer an interpretation, as shown on Fig. 2, where the carbonates and stratigraphically overlying shales form thin thrust sheets accreted beneath the Taconic Allochthon. Demonstrable tight folds and internal duplex faults within these carbonate sheets account for the many places where stratigraphic continuity is disrupted within them.

STOP 3. Pre- to syn-cleavage thrust
Pre- to syn-cleavage thrust of Poultney Formation over gray slates, above Taconic Frontal Thrust. Locality marked "P" on Fig. 2.
Plude's Quarry (Fig. 4) provides one of the few known exposures of Taconic continental rise rocks lying directly upon the underlying melange/flysch sequence. Several complexities of Taconic thrusting are evident at this stop. Along Carleton Road the shales and graywackes of the Taconic flysch are broken into a melange fabric, that grades up into the quarry with progressively less disruption, until a planar slaty cleavage is found. This is the Taconic Frontal Thrust, and can be mapped as in Fig. 2. Within the quarry a second, earlier fault is present, separating easily identified Lower Poultney slates and thin arenites from an underlying gray slate. The regional slaty cleavage cuts the fault, suggesting that this structure may be of the same generation as Rowley and Kidd's (1982) "Taconic Basal Thrust". 'The gray slates are interpreted to be a unit within the Middle Ordovician Taconic Flysch (allochthonous? parautocththonous?), and hence the fault is inferred to be a thrust. Fig. 4. Exposed pre-slaty cleavage thrust in quarry face (Plude's Quarry, Stop 3; location marked "P" on Fig. 2). Allochthonous Poultney Formation rocks were thrust over gray shales and then folded and cleaved. Thrusting and folding were apparently in part synchronous, as the amplitude of the fold in the thrust surface in the easternmost anticline is less than the amplitude in the folded Poultney. The gray slates most closely resemble a flysch lithology, although whether it is allochthonous or parautochthonous flysch cannot be demonstrated without biostratigraphic control.

STOP 4. Delaware and Hudson Railroad cut
Delaware and Hudson Railroad cut 300m NE of crossing Whitehall-Fairhaven Turnpike. Locality shown with "R" on Fig. 2.
At the east end of the cut (Fig. 5), both sides expose thinly laminated, brown fine-grained arenites in dark slate belonging to the upper Hatch Hill or lowermost Poultney Formations (Cambrian - earliest Ordovician) of the Taconic Allochthon. These are in contact across a steep fault with thicker bedded coarse dolomitic (locally calcareous) quartz arenites and quartzites in black slate of the middle to lower Hatch Hill Formation *(mid-late Cambrian). In the western portion of the exposures, best seen on the northern side, these dark slates, with variable quantities of arenite beds, are in repetitive thrust fault contact with massive greenish micaceous wackes of the (Taconic) Bomoseen Formation (early Cambrian or older). At the western end of the cut, the last exposure contains a fold in Hatch Hill slate and arenites such that bedding surfaces in the slate form the face of the exposure on one limb of the synformal fold. This western end is close to but not quite at the Frontal Thrust seen at Stop 3. On the hill to the north a southward-thinning thrust sheet of shelf limestones occurs between shaly melange below and Taconic rocks above, such as are seen in this cut and at Stop 3. A unit of shaly melange up to a few meters thick occurs between the limestone and the Taconic rocks, and was seen at Stop 3. The western part of this exposure, with the complex slicing and phacoidal cleavage in the black argillite, can be regarded as transitional, in a structural sense, to the melange. The disposition of the Hatch Hill and Bomoseen can be interpreted as an earlier thrust that has been folded and cut by younger, more steeply inclined thrust faults. Fig. 2 shows that the occurrence of a Bomoseen-derived slice immediately above the Taconic Frontal Thrust, followed by a Hatch Hill/Poultney-derived slice, is characteristic of much of the Taconic area bounded by the folded thrust that occurs near the Allochthon boundary in this region. Structures in the railroad cut that we connect with the emplacement of the thrust sheet are fault-related features, particularly slickensides, summarized in Fig. 6. A Riedel and anti-Riedel fault set are interpreted to be present and are consistent with thrust movement towards the west-northwest. We emphasize the brittle nature of this deformation.
* bolded material was inadvertently omitted from the printed copy in the published field guide

STOP 5. Mettawee River Section
Parautochthonous flysch in contact with autochthonous(?) shelf carbonates. Lunch stop; location given in Fig. 7.
The Mettawee River here provides a superb series of exposures that cross from autochthonous(?) shelf carbonates (where we will stop for lunch), through alternating zones of flysch and melange, to a large sliver of Chazyan carbonate, and on into allochthonous Taconic lithologies (Fig. 7). The only area that is poorly exposed in the river is the eastern edge of the carbonate sliver, but mapping demonstrates that this fault contact (the Taconic Frontal Thrust) cuts obliquely across Taconic stratigraphy and large-scale fold axes, and is therefore a post-slaty cleavage generation structure (Figs. 7, 8).
As at Stop 2, some workers are of the opinion that the allochthonous carbonate at this locality (D.W.Fisher, pers. comm.,1983) and along the western edge of the Allochthon in general (J.Rodgers, pers. comm., 1983; Rodgers and Fisher, 1969) is better interpreted as blocks-in-shale (i.e., olistoliths) than as coherent fault slivers. This locality provides an excellent means to test these two hypotheses. The carbonate/melange contact can be walked from point "X" to point "Y" (Fig. 7) with little difficulty (after wading across the Mettawee.... access at "Y" is limited by buckshot). The carbonate is seen to be continuous, essentially unbroken along strike, with internal fold axes approximately parallel to the general contact trend (see Selleck and Bosworth, 1985, Plate 1A). The carbonate must be in the form of a large sheet, or composite sheet, which could be called a single "block". Minor disruption near its margins is undoubtedly present, but the structural style is dominantly detachment of underlying autochthonous shelf rocks and their imbrication at the base of the advancing allochthonous thrust pile. It is misleading to describe the geometry of the large carbonate bodies along the western edge of the Allochthon as "blocks-in-shale", and it is very unlikely that they arose as sedimentary slump features (further discussed in Rowley and Kidd, 1982).

STOP 6. Imbricated carbonates, shales and melange
Imbricated medial Ordovician carbonates, shales and melange just below the Taconic Frontal Thrust. Vermont Route 22A 6.5 km north of Fair Haven. Location shown with arrowhead on Fig. 9. The part of this roadcut to be examined is illustrated in Fig. 9, and consists of the outcrop opposite the parking area and its continuation to the north. A thrust-repeated section of medial Ordovician strata is discernable from medium-bedded limestone (fossiliferous calcarenites to calcisiltites) without shale - Orwell Limestone, passing up abruptly into thin-bedded limestones (micrites) interbedded with dark shale - Glens Falls Limestone, overlain by dark shale, in part melange - here referred to as Hortonville shale (and the melange perhaps as Forbes Hill "conglomerate"). It is important to recognize that the dark shale, in the first instance, is a stratigraphic member of this succession, just as it is in the autochthon to the west (e.g., in the Mohawk Valley). That some of it has been structurally damaged by the imbrication and duplication of the sequence is a secondary effect, reflected in the lenticular (phacoidal) cleavage visible especially in the shale closest to the base of the succeeding limestone. Two of the eight sections lack the basal Orwell Limestone, probably because of local ramping of the active thrust, or original irregularities in the depositional arrangement. It is not valid, in our view, to regard this exposure as "all melange" with blocks of limestone floating in shale. Rather, it is a thrust-imbricated repeated lithic sequence, probably forming a thrust "duplex" above more extensive shaly melange, not containing limestone clasts, that is exposed on the slope to the west of the parking lot and in the separate road cut on 22A about 100 m north of this outcrop. The duplex is below the Frontal Thrust of the Taconic Allochthon which comes to the surface about 50 m east of this road cut; wackes of the Bomoseen Formation of the Allochthon form the prominent topographic feature of "the Great Ledge" visible to the east from the parking lot. More extensive massive limestones (Orwell, and perhaps Middlebury Limestone as well) that form road cuts along 22A just to the south are thought to be larger slices in the duplex zone. Noteworthy in the narrow (less than 1m) zones of shaly melange beneath each slice of limestone in the cut are a few blocks and cobbles of green micaceous arenite identical to the Bomoseen Formation of the Allochthon. The largest of these (approx. 1 m across) occurs at the very northern end of the outcrop, but other smaller ones occur within the outcrop near 30-40 m on the diagram. These we do interpret as olistolithic clasts shed from the front of the Taconic thrust sheet during its motion, and they require that the active thrust outcropped on the sea-floor, at a deep-sea trench-type feature. A similar, but larger (several m across) olistolith of Bomoseen wacke occurs in the outcrop of melange to the north. It is our observation, however, that there is a limit of a few meters to the size of these blocks that are clearly identifiable as olistoliths. Truncated bedding, slickensides and other features characteristic of ramp-flat thrust geometry can be seen in this outcrop. The present attitude inferred for the Taconic Frontal Thrust (about 10° east dip) and the steep east dip of these limestone-shale imbricate slices are consistent with their identification as duplex structures. Their attitude is not consistent with a model of tabular olistolithic slabs lying in the bedding orientation.

STOP 7. Boss Hogg's Quarry
Marked "H" on Fig. 9. Permission must be obtained from the owner to visit this locality.
The quarry exposes part of the early Ordovician Providence Island Formation, mainly dolostones with some limestone, not far below the overlying Middle Ordovician limestones (Middlebury) that outcrop to the east (see Fig. 9). The purpose of this stop is to see the structural condition of carbonates within the areally extensive thrust sheets that exist at this latitude between the Frontal Thrust of the Taconic Allochthon and the autochthonous shelf strata. On the south side of the entrance to the quarry a close synformal fold displays well-developed solution cleavage and marked changes in thickness from the short, west-dipping limb to the long, east-dipping limb due to more homogeneously distributed ductile shape change. A complementary antiform is exposed on the north side of the entrance linked to a synform that trends along the northeast face of the quarry. A wrench fault passing through the quarry entrance must offset the fold hinges in a left-lateral sense. The contrast between the substantial ductile strain shown in this outcrop and the lack of such features at Stop 1b in the autochthon is a reflection of the thrust translation of these carbonates and deformation during active movement on lower thrusts. The cleavage at this stop is roughly parallel with that in Taconic rocks exposed to the east. However, this does not necessarily make the cleavages the same age; evidence exists to suggest that they are not, and that the Taconic rocks were cleaved and folded before emplacement over this portion of the shelf carbonate terrane.

STOP 8. Scotch Hill syncline at Glen Lake.
Permission must be obtained from the owner (in the house across the road). NO HAMMERS ALLOWED. Location shown on Fig. 1.
This outcrop exposes early Ordovician strata of the Poultney Formation, probably about the same age as the carbonates of Stop 7, but a very different facies deposited in deep marine conditions on the continental rise. These rocks consist of green mudrock (slate) alternating with thinner laminated layers of fine sand to silt size arenites and quartzites that are interpreted as contourite deposits, and black/gray mudrock (slate) laminae. The black mudrock layers are probably pelagic; the green are likely mud contourites. The syncline exposed here is the single major hinge of a fold that is in a set with wavelengths of the order of 1 to 3 km and amplitudes of similar amount. The folds are tight to near isoclinal in form. This outcrop does not give the impression that the folds are this tight since the full transition to the fold limb bedding attitudes, particularly on the overturned limb, are not seen in this exposure. This particular fold can be traced north for 3 km and south for 8 km from this place; another single fold in this set in the northern Taconics can be traced for at least 50 km along its axis, characteristic of their subhorizontal to gentle plunges. The overturned nature of this fold, with its moderately east-dipping axial surface and near-axial planar cleavage is also typical of the structure of the low Taconics (Giddings Brook Slice). In detail, small parasitic folds in the quartzites in this outcrop can be seen to be transected by the slaty cleavage, suggesting that buckling of thin layers in response to shortening took place, as is usually the case, before thicker composite layers that generate longer wavelength folds. Thus the cleavage may be axial planar to the large-scale folds but not to the smaller ones. Examples of cleavage refraction can also be seen, and cleavage parallel quartz veins (? post-cleavage) are also present. We emphasize the coherent ductile deformation seen in this outcrop, characteristic of all the western Taconics in the northern part of the Allochthon. In our view it does not support the idea of the emplacement of the Allochthon as a gravity slide of unconsolidated sediments. Comparison of structures here with those in the thrusted carbonates (Stop 7) and at the western edge of the Allochthon (Stop 3) are consistent only with thrust emplacement of coherent, consolidated rock, undergoing related ductile deformation (folding and cleavage formation) at different times in different places during the overall assembly of the thrust sheets.

STOP 9. Shelf carbonate duplex
Shelf carbonate duplex beneath the Taconic Frontal Thrust at Bald Mountain, N.Y. Location given in Figs. 1 and 10.
Bald Mtn. has been a perennial favorite for stops in field guide books of eastern New York, and several excellent descriptions of the locality are available in the older literature (Walcott, 1888; Ruedemann, 1914) More recent discussions can be found in Platt (1960), Sanders, et al. (1961), Zen (1967), Bosworth (1980) and Rowley and Kidd (1982).
We have intentionally placed the Bald Mtn. quarries at the end of our trip, despite their proximity to Saratoga Springs. We have been emphasizing processes related to frontal imbrication, multiple generations of thrusting and the formation of duplexes throughout the day. We feel that the examples we have presented are fairly convincing. Bald Mtn., however, is shrouded with historical overtones, and is also exceedingly complex. The general picture is quite clear: the uppermost portions of the quarries are composed of allochthonous Taconic lithologies, these overly a thin zone of phacoidally cleaved shales, which in turn overly discontinuous masses of shelf carbonate (some quite large) and more phacoidally cleaved shale. But the details are not so clear. Are the carbonate blocks fault slivers, or are they olistoliths within a large-scale sedimentary slump mass, subsequently overridden by the Taconic thrust sheets (Rodgers, 1952; Rodgers and Fisher, 1969)?
We recognize some internal order in the disposition of lithologies in the area of the Bald Mtn. carbonates, with similar lithologies aligned along strike (Fig. 10). Several of the carbonate blocks are probably hundreds of meters in length, not unlike the Chazyan sliver on the Mettawee River (Stop 5). As at Stops 5 and 6, small rounded cobbles of limestone (in this case) within the phacoidally cleaved shale zones may in fact be olistoliths, probably derived at subaqueously emergent fault scarps from the main masses of carbonate themselves (Rowley and Kidd, 1982; Bosworth and Vollmer, 1981). However, we again feel that the structure at Bald Mtn. can reasonably be interpreted as a fault duplex (Fig. 11), as was first proposed by Ruedemann (1932, p. 134). We encourage all participants to share their thoughts with the rest of the group!
A regional compilation of presently identified structures believed to be associated with the Taconic Frontal Thrust System (youngest Taconian deformation) is presented in Fig. 12.

A3: TRI-CORN GEOLOGY THE GEOLOGY, HISTORY, AND ENVIRONMENTAL PROBLEMS OF THE UPPER HUDSON CHAMPLAIN VALLEY
Anson S. Piper
Adirondack Community College
The region of the upper Hudson-Champlain valleys provides an excellent locale for the teaching of introductory geology courses. In addition to the desired examples of geologic phenomena there are ample opportunities to relate geology and human activities past and present and areas where various field methods may be used to solve very simple problems. It is the purpose of this trip to tour the area from Saratoga Battlefield north to Ticonderoga, view points of geologic, historic and environmental interest and to try to relate them one way or another together.

A3: TRI-CORN GEOLOGY THE GEOLOGY, HISTORY, AND ENVIRONMENTAL PROBLEMS OF THE UPPER HUDSON CHAMPLAIN VALLEY

STOP 1. Saratoga National Park Visitors Center
The battles fought here were, collectively, one of the most decisive actions during the course of North American history. They represented the climax of a complex, three-pronged campaign, which, had it succeeded, would have cut the rebelling colonies in two, probably winning the war for the British. The American victory assured recognition by France and subsequently to the alliance.
The choice of ground was made by the Americans, who drew up their lines overlooking a narrow defile along the Hudson. Entrenchments were dug along Bemis Heights under the direction of Col. Kosciusko. The area was sparsely settled, with farms in scattered clearings, connected by wagon roads through the forest. Where the roads traversed sand, they were difficult to move over with heavy loads. Where they traversed clay, they were impossible when wet, and if rutted, nearly the same until beaten down. Burgoyne, with his heavy train of baggage and artillery, was forced to descend the river using batteaus for his supplies while his men trooped along the parallel road. He had crossed to the western side just north of present day Schuylerville (Saratoga). The American defenses, therefore, commanded his route along the river and extended westward to prevent his flanking them.

This is the "280 ft." level of proglacial Lake Quaker Springs.

The "250 ft." level of Lake Coveville.

Coveville Plunge Basin.
Drainage from the Ballston Channel combined with waters of the Kayderosseras dropped into the almost river-like Lake Fort Ann.

Site of Ft. Hardy, Where British grounded arms, is on the flood plain to the right.

Burgoyne's final positions.

STOP 2. Stark's Knob.
Pull off road and park. Hike up road leading west past the knob. THE EXACT OWNERSHIP OF THIS SITE IS, AT THE TIME OF PUBLICATION, UNKNOWN, BUT IT IS NO LONGER THE PROPERTY OF THE STATE OF NEW YORK, HAVING BEEN DEEDED TO THE TOWN OF NORTHUMBERLAND. THE TOWN IS THOUGHT TO HAVE DISPOSED OF IT TO A PRIVATE INDIVIDUAL, WHO DENIES THAT IT IS HIS. AS THE RESULT OF REPEATED INTRUSION ONTO HIS ADJOINING LAND, HE HAS MADE IT KNOWN THAT HE WILL HAVE ALL PERSONS WHO STRAY ON TO HIS PROPERTY ARRESTED.
IT IS THEREFORE IMPORTANT THAT VISITORS STAY ON THE TWO ACCESS PATHS TO THE SITE AND AVOID CROSSING THE OLD FENCE LINES.
The Knob is named for General Stark. who placed his artillery atop of it in the final days of the campaign, thus blocking the withdrawal of the British up the Hudson River and along its western bank. The knob has been formed by the differential erosion of the soft black shale from around the more resistant basalt of the pillow lava. Both the shale and the pillow lava are part of an overthrust block of Ordovician rock displaced a considerable distance from the east during the Taconic events.
The material between the pillows contains fragments of the carbonates through which the lava appears to have passed on the way to the surface. The pillows themselves, have a chilled surface and are laced with quartz and calcite filled fractures. Several small faults cut down through the quarry face and water moving along these has formed a small spring at the base near the large pine tree. The basalt was quarried for "road metal" prior to its acquisition by the state.

Fort Miller
The fort was built on the opposite side of the river, to protect the portage around rapids or a small falls on the river. It was a wood stockaded "star fort".

The old Champlain Canal on the right.
This old canal wanders along, following the contours in order to reduce the number of locks. Rt. 4 crosses its path.

Exposure of black shale and sandstone in a near vertical attitude.
A few graptolites have been collected here dating it as part of the Taconic over-thrust.

Bridge over the Champlain Canal.
The Hudson River is seen below the locks. This water barrier was nonexistent during the 18th century so that it was easier to build the military road down this side of the river.

The Fort House Museum
(Time permitting, a brief stop.) This house was built prior to the revolution of materials said to have been scavenged from the buildings at the fort. There is an old, but never-the-less good, model of Fort Edward - a typical earth and timber fort.

Bridge over Fort Edward Creek with an old canal aqueduct over it to the right.

Site of Fort Edward
All that remains of this, the largest British military installation in North America prior to 1800, is a small portion of the moat. It was essentially a three bastioned earth and timber fort, built over a period of two years on the site of earlier Fort Nickolson. Additional works were built on "Roger's Island" the home base of Roger's Rangers. The fort was never besieged or defended except against small raiding parties. It was placed here at a position of great strategic importance, but like Ticonderoga, it was overlooked by high ground making it indefensible. Seven blockhouses were placed around it to cover the weaknesses in its approaches. This point is the furthest extent of the navigable waters of the Hudson and the southern end of the portages to Lakes George and Champlain.

This canal was completely plugged following the removal of the power dam.

STOP 3. Roger's Island
In the early 1970's, the Niagara-Mohawk Power Corp. received clearance to remove a small power dam located just north of the island. The volume of sediment entrapped behind the dam was greatly underestimated and the P.C.B. content was not recognized as a hazard and ignored. When the spring flood occurred, a huge volume of P.C.B. laden sediment washed down stream, leaving the north channel plugged and the south channel nearly so. This resulted in three major problems: the navigational channels were plugged here and downstream, P.C.B 's entrapped in the sediment were distributed with them and raw sewage from the Village of Fort Edward was piled up atop of the plugged channel.
The New York State Department of Transportation dredged out the channels and stored the material at the DOT sites on Roger's Island and on the Town of Moreau side of the river. It was an annual event for several years until the bulk of the sediment was washed out and the nature of the P.C.B. problem "surfaced". During the last dredging, the P.C.B. threat, having been recognized, workers were required to wear dust masks and the material was encapsulated, the previous dumpsites were covered with a temporary cap of clay. An unexcavated archeological site was buried in the, process.

STOP 4. D.O.T. Site
This is an encapsulated dump site for the P.C.B. laden sediments dredged from the Hudson River at Roger's Island. The debris was placed in a clay lined pit and then covered again with clay. It is a temporary disposal site.

Marker on left for the McCrae House
After making turn note marker on left for the McCrae House where Jane McCrae was taken by Indians. Rt. 4 approximately follows the military road to Lakes George and Champlain.

The approximate site of the killing of Jane McCrae.
A blockhouse was situated about where the school athletic field is. The road is climbing up onto the sand delta deposited into Lake Coveville.

STOP 5. Fort Edward General Electric Plant & Union Cemetery
This is one of two General Electric plants locally which manufacture electrical components (capacitors chiefly) previously using P.C.B.'s. To the right rear, next to the Grand Union Store, is an Agway Farm Store, which sells pesticides and herbicides to local farmers. Union Cemetery, located to right, is the burial place of several persons of note, including Jane McCrae, Duncan Campbell and Tobert Cochran.
The location is atop a sand delta (Lake Coveville) some 15 to 20 feet thick overlying a shale which crests under the General Electric Plant and slopes away toward the river to the southwest and the Champlain Canal to the northeast.
Two groundwater problems have developed here, the first involving agricultural chemicals and the second, P.C.B.'s and T.C.E.. Most of the local dwellings have their own water wells, some of which have become polluted by either or both types of chemicals. The pesticides and herbicides have shown up in wells on Putnam Avenue and Ethan Allen Street southeast of the Agway Store and extend as far as Burgoyne Avenue. The seemingly harmless act of washing trucks appears to have been the cause of this problem. One more good example of why ordinary people need a better education in geology. The P.C.B. - T.C.E. problem is more complex. Both chemicals were uses extensively at the General Electric Plant and the deliberate and accidental spills over many years have gradually polluted the groundwater about the buildings. In addition, some individuals have dumped the industrial chemicals at their homes where they have been salvaging materials or using T.C.E. on their own projects. Wells along adjoining streets have been abandoned and these homes have been connected to municipal water systems, the cost being borne by G.E. There is very extensive litigation involved in these cases and little information can be gained from the parties involved.

Ciba-Geigy Plant and wastewater treatment plant.
Prior to the construction of the treatment plant, waste water containing heavy metals was discharged into the Hudson adding to the pollution from the paper mills upstream. Following the imposition of environmental controls, this installation was built to separate the toxic components from the water which is returned to the river cleaner (supposedly) than when it is taken out. The solids are then hauled to the Queensbury Landfill where they are placed in a disposal basin.
The road climbs up onto another sand deposit, this one is probably related to Lake Quaker Springs.
Across the river to your rear, is the Glens Falls Cement Quarry showing the thickness of the sand overlying the carbonates. The cement plant was the center of an air pollution study done by Adirondack Community College students many years ago. The study pinpointed the plant as a major source of particulate matter in the air and with the passage of clean air regulations, the old stack was replaced with one containing "scrubbers" and the problem was essentially solved. The Glens Falls Limestone quarried here was previously produced from tunnels underlying the Village of South Glens Falls.

Dix Avenue is following the route of the old military road to Lake George.
It skirted the low area through which we have just passed, and swung west and then north to avoid the swamp through which Quaker Road passes.

Prospective Peat Farm
Peat deposits have formed in swamps which developed on Lake Albany clay which sealed the underlying limestone. The development is stalled pending a decision related to the Wetlands Protection Act.

You are now entering "New France"
You are now entering "New France" as you cross Halfway Brook and enter the St. Lawrence drainage basin.

Brief Pause - Adirondack Community College Quarry.
This exposure of Ordovician, Beekmantown Carbonates, contains a breccia, (fault or collapse ?) some small cephalopods and burrows of a sort. The campus is located on a downfaulted block (a graben) with a fault running approximately across Bay Road and another somewhere between the rear of the buildings and the next ridge to the east. Other structures are suspected because of the change in the attitude of the rocks in the several outcrops on campus. A small fault with a 2 inch displacement has been found. In addition, there is an exposure with enlarged solution joints, perhaps formed during the post-glacial interval while Lake Albany was draining. The soils on campus are lake clays (some varves were found in the building excavations) and to the west and north, is the kame and esker complex.

The road climbs up onto the kame and esker complex.
Blind Rock was a locality where native war parties often took prisoners for torture.

Round Pond and Paradise Beach.
A kettle lake with an esker on each side at the far end. The one extending along the north side continues along the right side of the road.

This is near the epicenter of a number of very small quakes
This is near the epicenter of a number of very small 'quakes (.5 Richter or less) which were detected during a study done by the N.Y.S.G.S. Rt. 9 passes over 5 Mile Run, the site of several ambuscades, just in front of the Great Escape Amusement Park! The low area on the right, past the park is an extension of Glen Lake, an iceblock lake .

Kame terrace capped by Lake Albany sands.

STOP 6. Col. William's Ambush
PARK ALONG ROAD SIDES WHERE IT IS SAFE. THIS IS A DANGEROUS SITE.
The outcrop is on the west side of the road and is extremely hazardous because of traffic. The bedrock is Precambrian (Grenville) Gneiss and is cut by several nearly strike-slip faults running parallel to the road. At one point a small dike is cut into three sections by the faulting. Prior to the widening of the road, there was a fine, fluted, slickensided surface exposed. French Mt. opposite, is a horst.
The military road passed below the present road and this was the site of the French ambuscade of the Provincials and Iroquois, known as "The Bloody Morning Scout". Col. Ephraim Williams, whose estate founded Williams College, was killed standing on a glacial boulder, while old "King" Hendrick toppled from his horse and was bayoneted. The colonials and Mohawks successfully withdrew from "Rocky Gulch" to Lake George, leaving about 100 casualties behind.

Bloody Pond, a kettle lake and the scene of two skirmishes.

STOP 7. Fort George And Battlefield
Here is another exposure of Ordovician, Beekmantown carbonates, dipping about 5° northeast and lying between two mountains of precambrian rock. This presents an opportunity for solving a very simple structural problem Three responses are usually evoked from beginning students when asked to explain it:
1. The rocks were derived from the older rocks and deposited here.
2. They were downfolded into the valley form.
3. They were downfaulted.
The first choice is eliminated by the character of the sediment, and the others require further information to be gained at the next stop.
The carbonates were first used to build the stone bastion of Fort George, which was built following the Battle of Lake George. The rocks provided both the building stones and the mortar to hold them in place. The present structure has been partially restored.
The battle here followed the Bloody Morning Scout, Dieskau, the French commander launched a series of assaults on Johnson's camp and was repulsed with heavy losses. Both officers were wounded and Dieskau taken prisoner. The French and their allies fled to Bloody Pond to loot the packs of the men killed there earlier, where a relief column of over 600 men from Fort Edward caught them disorganized and scattered the survivors.
After the battle, Fort William Henry was finished on the sand terrace overlooking the lake. The fort was built of timber cribs filled with sand from the moat. The main gate was on the south side, and a stockaded area on the north. The choice was poor in the sense that the sand, being easy to dig, allowed Montcalm to advance his saps and parallels very quickly when he laid siege two years later in 1757. His artillery quickly reduced one bastion. The sand pouring out through broken timbers caused it to collapse and the fort surrendered. The attack on the unarmed British prisoners following the surrender is a matter of historic record.

STOP 8. Exposure of the upper Cambrian Ticonderoga Formation
This exposure of the upper Cambrian Ticonderoga Formation dips gently toward the northeast and consists of mostly sandstone which places it in the upper third of the formation but not at the top which contains some chert. There are ripples and stromatolites present, the latter being in the reddish-brown dolomitic layer at the top of the ledge. The upper surface has been planed smooth by glaciation and the direction of movement has been recorded in striations found there. Visible to the west is an exposure of precambrian rock at the bend in the road. These observations tend to support the hypothesis that the valley floor is a downfaulted block or graben. Further support to the idea comes from the existence of two magnetic anomalies between the two outcrops. (Personal communication from John Mead) A similar relationship between the Precambrian and the carbonates can be seen along the east side of the valley. (Along Rt. 9-L near Crosbyside)

The road follows the trace of the English Brook Fault.

Brief Pause - The English Brook Saprolith
Note: This exposure of deeply weathered rock has been known since the 1930's and has miraculously survived repeated road improvements. Originally, the exposure was topped with two layers of glacial boulders separated by a lake sand. Each spring these came rolling down - some three feet in diameter - to the dismay of the highway department. Their recent removal and the gradual covering of the face in its own debris has greatly altered the appearance of the site. The preservation of the saprolith is thought to be the result of deep weathering along the plane of the fault and the transverse orientation of the fault to the direction of ice movement. This is one of the few such exposures which can be easily seen in New York State.

Note en route: This valley was occupied by Glacial Lake Warrensburg
Note en route: This valley was occupied by Glacial Lake Warrensburg, evidence for which is seen in the numerous sand deposits along its floor. Just short of Milepost 63, the road cuts show precambrian rocks on one side and layered sediments on the other, the road straddling a fault.

Roger's Rock State Park And Campsite.
Named for Roger's Slide thought to be the fault scarp forming the east side of the Lake George graben and the scene of Major Roger's escape from the French and Indians, March 13, 1758.

Ticonderoga Creek - The outlet from Lake George flowing into Champlain

STOP 9. Fort Ticonderoga (Carillon)
This fort is built near if not on the site of Champlain's skirmish with the Iroquois in 1609. Construction was started in 1755 and essentially completed by 1758. Modifications, repairs and improvements continued until the end of the American Revolution, when it was allowed to fall into total disrepair.
The original construction was of earth and timber, later on improved by stone facings. The fort was designed for a small permanent garrison with extensive outworks for a larger "summer" army. The location was poorly chosen, since the works are well within range of siege guns placed on the heights of Mt. Defiance.
The stone fort was built from Ordovician limestone, quarried on the site, and was in total ruin prior to reconstruction. The stone work, weakened by solution and frost action, had collapsed into the moat, and hauled off to build "cellar walls" by the post war settlers. The original foundations can be recognized in the walls by their weathered appearance.
Mt. Independence, on the opposite shore, was linked to the fort by a bridge consisting of 22 sunken piers connected by 12' X 50' "pontoons" chained together. The piers still survive in the muddy floor of the lake and are currently being salvaged (?) along with numerous other artifacts of the Revolutionary War.

South Bay, Lake Champlain

Note Rock Falls along road cuts .

STOP 10. The Hudson-Champlain Canal
The canal follows the general path of wood creek which rises near Fort Edward. During the spring of 1984 this area was badly flooded when water backed up behind a coffer dam following a heavy rain. The dam, installed to permit repairs on the canal, was not designed to accommodate the sudden rise of waters and considerable damage was done to the small museum here and other structures.
Historically, the locality was called Skenesborough, after Philip Skene, a prominent Tory. The claim to be the "birthplace of the United States Navy", stems from the fact that Benedict Arnold's fleet was built here, the first continental squadron. Although it was defeated at Valcour Island, the fleet delayed the Burgoyne campaign until the next year. The hull on display here is a survivor of the Battle of Plattsburgh Bay, during the War of 1812. A military road was built from here to Fort Edward and later improved by Burgoyne.

This road will follow closely the old military road parallel to Wood Creek.
It travels over the floor of Lake Fort Ann.

Lake Clays On Right - Note Slumping
Champlain Canal Locks on left.

Note: Rockfalls In Road Cut.

Brief Pause - Road Cut In Precambrian Gneiss.
The foliation and some joints in the gneiss dip toward the east so that the road cut intersects or "daylights" them along the west side of the road. In order to reduce the chance of failure along these planes, the threatening blocks have been bolted into place with heavy threaded rods which penetrate into "solid" bedrock.

STOP 11. Unconformity
The base of the Potsdam Sandstone is exposed here in contact with the precambrian gneiss. The basal conglomerate above the unconformity contains many large quartz pebbles here. Additional exposures of the Potsdam may be found by walking down the side road to the left and just past the small valley, climb down over some old concrete slabs to a flat exposure. Graded bedding, crossbedding and ripples can be found here and in the railroad cut. Glacial striations, chatter marks and quarrying faces may also be seen. A commercial building stone quarry across the canal was previously operated and many local houses are built of this rock.

Battle Mt.
A rear guard action was fought here by the Americans fleeing Burgoyne's army. This was one of the first times that the "Stars and Stripes" were flown in battle.

Entering Fort Ann Village
The reconstructed blockhouse (bank) was originally intended for a museum. It is fairly accurately constructed and very close to the actual site of the fort which guarded the crossing of Halfway Brook where it entered Wood Creek. There was a stockade surrounding the blockhouse. Note the use of Potsdam sandstone in several of the older buildings.

Possible route for Burgoyne
Burgoyne's line of march probably followed Route 4, but it is also possible that he did follow this lower route.

Smith's Basin.
On the far side of the canal is an excellent section of Cambrian and Ordovician carbonates described by Donald Fisher in the N.E.I.G.C. Guidebook 61st mtg. 1969. An old limestone quarry and kiln was operated just across the bridge in an exotic block or thrust slice of Orwell and Glens Falls limestone. The basin was an old canal basin and at one time was a fairly large settlement.

Kingsbury Landfill (Closed)
Note also, the Feeder Canal, five "combines" Locks and small house at right of intersection beyond canal.
The Kingsbury Landfill is now probably the chief source of P.C.B.'s entering the Hudson River. Many capacitors were disposed of here and on summer days, their sweet odor can be detected. The P.C.B.'s are leaching out of the site, into the canal and into the Hudson River. Another path is into the groundwater and the lowlands below the site to the river. Current plans call for the capping of the site hopefully sealing it. General Electric has made a major contribution toward the cost, but the remainder must be borne by the local taxpayers.
The feeder canal served two purposes: to move barges to Hudson Falls and Glens Falls and to maintain the water level of the lower section of the canal.
The small house may have been Burgoyne's Headquarters when his army camped here. In any event, it is thought to be one of only two buildings not burned down during Carleton's Raid in 1780.

This is Baker's Falls, the highest falls on the Hudson.
While it is capped by a dam to increase its generating capacity, it is probably due to a fault. The river has cut a deep gorge through the softer shales below the falls.
It was the presence of this falls which caused Fort Edward to be built and the settlement of "Sandy Hill" to develop into the Village of Hudson Falls. The falls and dams upstream provided the water power for the early mills and later the hydroelectric generating plants, ultimately leading to the locating of the General Electric plants and the P.C.B. problem. It was also found that some P.C.B. was used to produce carbon paper upstream at a paper mill.

Caputo Dumpsite.
This site which is located along the right side of the road, in back of the houses was used to dispose of industrial wastes from the General Electric Company from about 1958 to 1970. It was an open pit into which barrels were placed, filled with waste, P.C.B.'s and T.C.E. The subsurface consists of glacial sands and lake clays overlying bedrock. The watertable is about 25 feet down. ENCON. well information indicates the following:
0 - 70 feet Medium to fine sand
70 - 95 feet Fine to very fine sand with silt lenses 1/8 to 1/2 " thick.
95 - 100 feet Fine sand - clay lenses with brown varves
100 feet + Gray clay and silt lenses over bedrock.
The site has been enclosed by 1600' slurry wall 100 feet deep and three feet thick in an attempt to contain the leakage. The slurry consists of 70% soil, 28% native clay and 2% bentonite. The whole is capped to shed water. The P.C.B.'s appear to be more or less contained and saturate the soil above the water table. The T.C.E.'s on the other-hand appear to have sunk down rapidly to about 70 feet. A plume has formed between 45 and 70 feet, spread out about one mile down gradient in 2-2.5 years. The water at the water table appears clean as does the water below 70 feet, thus the plume appears to be moving toward the southeast in a sheet about 25 feet thick at a present rate of eight feet per day.
Many residential water wells have already been polluted and some properties in close proximity are claiming unsafe levels of vapors within the structures. Because of pending litigation, it is difficult to obtain specific and valid information from some parties. The plume which is moving toward the Fort Edward water supply has shown up in a stream feeding it. A system of aerating the water has been installed which allows the T.C.E. to dissipate. Additional P.C.B.'s were sprayed along the Fort Edward road to settle dust and this has recently been removed by scooping up the contaminated soil and placing it at the Caputo Site where it is to be encapsulated.

A4: THE MINERALOGY OF SARATOGA COUNTY, NEW YORK
JOHN J. THOMAS AND JENNIFER A. RICHARDS
Saratoga Springs, NY 12866
Saratoga County includes within its boundaries the Adirondack Highlands and the Hudson and Mohawk Lowlands. The rock types range from the Precambrian Grenvillian granulites of the Adirondacks, located in the northwest quadrant of the county, through Cambro-Ordovician carbonate and clastic rocks. While the area is predominantly covered by Pleistocene glacial till and sediments of glacial Lake Albany, scattered bedrock exposures afford excellent mineral collecting.
Several of the county's most famous mineral collecting localities are either closed to the public or have been lost. An example of the former is the Gailor Quarry in Saratoga Springs. While the quarry is inactive, the faces have become very unstable and because of collector abuses, the owners no longer allow access. An example of a lost locality is the collection site for chrysoberyl, for which Saratoga County is famous.
The original description of the quarry measures its location from Route 9. Since the publication of the location, routes have been renumbered and relocated.
All of the localities that are listed in this guidebook are on private property and require special permission from the landowner to visit.
PURPOSE
The purpose of this field trip is to examine a variety of mining and mineral localities in Saratoga County that are typical of this area and the Southeast Adirondacks in general. The minerals available in large quantity are fairly common, but interesting in terms of size and development. The quarries visited will include a graphite mine and several pegmatites. Opportunities exist to collect a variety of minerals, observe the relationships between them, to study the mines' relationships with the country rock, and to see late 19th and early 20th century mining techniques.

A4: THE MINERALOGY OF SARATOGA COUNTY, NEW YORK

STOP 1. Wilton Graphite Mine
The graphite mine is located to the west of US Route 9. Enter the woods directly opposite Worth Road. There you will find a dirt road leading up the side of the mountain. The following measurements are taken starting from the west edge of US 9. All measurements are in feet.
467 | The foundation of a former building on the left.
1533 | On the right is the foundation of the boarding house for the mine.
1756 | On the left is the foundation for the loading bins. Horse teams took the refined graphite from here to the railroad.
1890 | On the left is the waste water dam and settling pond, even then a matter of controversy. Each year the pond was allowed to flush itself out into the fields below. If you follow the stream valley 1,000 feet upstream, on the right you will find the foundations of the concentrating plant which originally consisted of five levels. The original turbines are still here. There was also a steam generating plant here that supplied power for the mill and mine.
2725 | Stream crossing. Foundations on the left are for the upper level of the mill. A narrow gauge railroad serviced the mine from here.
2840 | A fork in the road, take the road to the right.
2935 | The cut on the right and left was a drainage ditch for the underground mine and connects with it.
2890 | The entrance to the underground mine, known as the mine, on the left.
3411 | Follow the main road
3591 | Another drainage ditch.
3833 | The trail from the Wilton-Greenfield Road enters on the right.
3982 | On the left is the large open mine, known as the quarry. Water fills the west end.
4326 | The road is now a trail. The end of the quarry.
The following description is taken from the Adirondack Graphite Deposits by H. L. Alling (1917).
The property was first opened about 1910 by the Saratoga Graphite Company which worked it in a small way for two years. After a few years the mine was taken over by the Graphite Products Corporation which enlarged the plant and the mine and worked it until about 1922.
The original mine is 22 by 30 meters and was worked only by the Saratoga Graphite Company. The Graphite Products workings consist of the mine and the quarry. The mine extends 115 meters along strike, inclines 38-42 degrees south. A number of openings have been driven down dip meeting two parallel horizontal drifts. The quarry is an open pit mine extending east-west, 125 by 30 meters. Now water filled, in 1917 it was 10 meters deep.
The rock containing the graphite is described as a quartz schist and occurs in two outcrops, the mine and the quarry, repeated by faulting. From Alling (1917, p. 106) describing a south to north section (fig. 1), " ... a serpentinous limestone forms the bed of the brook .. , next rock to the north is a para-amphibolite grading into the quartzite ... injected and saturated by Laurentian Granite a lenticular mass of metagabbro ... a siliceous limestone ... beneath the limestone the graphite schist shot through with 'pegamatitic material which forms knots and stringers' a fault parallel to bedding occurs here ... a gap in the cross section Pegamatite, quartzite, and metagabbro ... a reddish garnetiferous quartzfeldspar para-gneiss ... The rocks here are faulted and penetrated by pegmatite ... It is not possible to name with certainly the rock forming the floor of the quarry ... The north end of the section ends in a limestone." The section as described correlates with the Spring Hill Pond Formation of the southeast Adirondacks. A diabase dike 10 meters wide outcrops just west of the mine. A second dike, 25 cm. wide, outcrops west of the finishing mill.
The ore is similar to the American, Hague, Flake and Hooper ores. Graphite content is 7-8% all flakes are less than a millimeter in diameter. The outcrop is badly weathered, but at the bottom of the inclines in the mine is in better condition.
The mining technique was primitive by any standard consisting of steam drilling, hauling the ore out of the mines with donkey engines, and loading it into wagons. Teams hauled the ore to the narrow gauge mine cars which took it directly to the concentration mill. The usual Adirondack milling practice of crushing, stamping, puddling, screening and drying was used. The finishing mill used Hooper pneumatic jigs which prepared the graphite for market.
Minerals and Rocks: Apatite; Diabase; Graphite; Pegmatite; Phlogopite; Quartz schist

STOP 2. Black Pond Pegmatite
The Black Pond Pegmatites, unreported in the literature, were mined in the early twentieth century for abrasives used in Bon Ami Cleanser. The description of these bodies is taken from a 1984 field report by Tara Mandeville of Skidmore College.
Black Pond is one mile down the logging road from its intersection with Lincoln Mountain Road. The pegmatites are hard to spot from this direction. Directions for finding the bodies follows, the distances are in feet:
3450 - First sign of crushed pegmatite in the road.
4015 - Pegmatite (Ml) on the west side of the road.
4150 - Road on the west goes to the big pit (M2).
4365 - Pit on the west side of the road (M4).
4590 - Side road to the east (M6).
5110 - Black Pond.
As one approaches the outcrops from Lincoln Mountain Road (fig. 2), the first evidence of the outcrops is a tailings pile (Ti) adjacent to a small mine pit, Ml (approximately 4.6 m. long by 4.6 m. wide by 2.4 m. deep). The tailings are composed of feldspar, quartz and biotite. The pit contains several small pegmatites varying from pure feldspar to quartz-rich pegmatite with large crystals of biotite. The country rock is a biotite-quartz-feldspar gneiss.
The largest pit in the area (M2) is 30 m. x 12 m. x 9 m and is partially water filled. The coarse grained feldspar-quartz-biotite pegmatite is discordant to the 280,35W striking, medium grained, biotite-quartz-feldspar gneiss country rock.
Pit #3 (M3), 6 m. x 6 m. x 3 m., contains several smaller pegmatites that are partially concordant and rich in quartz. The surrounding fine to coarse grained gneiss contains abundant biotite. The adjacent tailings pile (T2) includes feldspar and rose and smokey quartz, but little biotite.
A very large tailings pile (T3) lies just south of Mine #3 and is probably the tailings from Mine #2. The tailings are dominantly country rock with some pegmatite. Large crystals of tourmaline were found in this dump.
Further south along the logging road a small overgrown trail enters from the east. Opposite this trail is Pit M4. This is a small quartz-feldspar pegmatite interrupted by a small lens of biotite-rich gneiss. At the entrance to the path is a small tailings pile (T4). Further up the path is a feldspar, quartz, biotite pegmatite mine (Ms) 6 m. x 9 m. x 6 m.
South along the main logging road toward Black Pond, a side road enters from the east. Along this road are feldspar-rich tailings (T5), several test pits containing quartzite (Q), and Mine #6 (6 x 3 x 2 m.) which is another feldspar, quartz, biotite pegmatite.
Along the northwest corner of Black Pond is the last of the pegmatites (M7). Here is a small discordant pegmatite in a gneiss which contains coarse grained feldspar and finer grained quartz and biotite. The tailings (T6) associated with this mine contain feldspar, rose and smokey quartz and biotite.
Minerals and Rocks: Rose quartz; Smokey quartz; Tourmaline; Biotite; Rose quartz graphic granite; K-feldspar; Graphic granite; Granitic gneiss

STOP 3. Mount Anthony West Pegmatite
The following description is taken from Geology of the Luzerne Quadrangle by W. J. Miller (1923). The pegmatite has not been described in detail, but is referred to several times.
Miller (1923) describes west of Mount Anthony a terrane of metagabbro-granite rocks where many small pegmatites without sharp borders cut across the foliation. Magnetite, in amounts to be classed as ores, in 1923, is observed associated with granite, pegmatite, and metagabbro. This stop has been selected for this magnetite-pegmatite association. The magnetite is always in moderately coarse grained, gray pegmatite in masses up to 2 or more centimeters across. The country rock is a garnetiferous Grenville gneiss or amphibolite. Mines in this area were worked 90-100 years ago and some ore was shipped. Also, attempts were made to use the white feldspar in the pegmatites.
Minerals and Rocks: Pegmatite; Magnetite; Country rock

STOP 4. Overlook Quarry
The following map (fig. 3) and description are taken from Tan (1966). Miller (1923) describes the Overlook Quarry as producing pottery feldspar as late as 1920. pegmatites.
The country rocks are granitic gneiss and magnetite-bearing metagabbro. pegmatites.
The border and wall zone (I) is in sharp contact with the country rock. The border zone is difficult to distinguish from the wall zone. The border zone is fine grained in places. A lens rich in andesine which occurs at the west margin of the ore body is interpreted by Tan to represent an incompletely developed border zone, although a segregation (replacement) origin is possible. In the border and wall zone, both pink and white potassium feldspars are found and a coarse graphic texture is common. Associated biotite plates are more than 1 m. in diameter. pegmatites.
The intermediate zone (II) is mainly white potassium feldspar crystals up to 1 m. across, with subordinate amounts of quartz, plagioclase, and large black tourmaline crystals which reach lengths of 15 cm. or more. pegmatites.
The core zone (III) is rose quartz and crosscuts the intermediate zone (II). pegmatites.
Minerals and Rocks: Albite; Allanite; Magnetite; Manganoaptite; Oligoclase; Orthoclase; Rose quartz; Smokey quartz; Thorite; Tourmaline; Zircon (Cyrtolite); Graphic Granite; Andesine; Biotite; Microcline; Monazite; Plagioclase; Polyclase; Quartz var.; Sericite; Uranite; Uranothorite; Manganoan-flourapatite; Country rock

STOP 5. Batchellerville Quarry
The following description is taken from Tan (1966). The Batchellerville deposits can be reached by a logging road at the rear of the mobile home park east of Saratoga County Route 7. The outcrops consist of two pegmatite bodies (fig. 4) reported by Newland and Hartnagel (1939) and six more bodies found by Tan (1966).
The bodies were worked by the Claspka Mining Company in 1906 and were still mined in 1916 and 1921. Mining was for microcline for the ceramic industry. Most of the pits show only wall rock with the central productive portions, the pegmatite, having been removed. The small size of the mining pits indicates that the production was never great. The deposits are famous for having yielded the largest beryl reported in the state, 69 cm. long and 25 cm. in diameter. The muscovite contains too many iron inclusions for electrical uses.
In the lower pit, the contact between the pegmatite body and the wall is sharp. On the south wall the pegmatite body lies in a gently folded anticline plunging 30 degrees toward the south. Biotite, uraninite, pink and pale green apatite, and bladed allanite are found along the vertical northwest wall of the pit. In the wall zone (III), scrap muscovite (about 1/4 to 1 cm. in width) appears. White graphic potassium feldspar with parallel short quartz rods is exposed in the south wall. The biotite is partly chloritized. Subhedral high-temperature quartz is intergrown with muscovite. Pyrite and low-temperature quartz crystals, with prism faces, are found in small vugs about an inch across. The intermediate zone (III) consists of giant white microcline about 1 m. long, muscovite columns, and small amount of quartz. The quartz core (IV) near its upper margin contains columnar muscovite crystals with lengths of 15 to 25 cm. Veinlets of quartz extend outward from the core and invade the microcline, but no sign of argillization or sericitization is observed.

A5: CORRELATION OF PUNCTUATED AGGRADATIONAL CYCLES, HELDERBERG GROUP, BETWEEN SCHOHARIE AND THACHER PARK
PETER W. GOODWIN, E.J. ANDERSON, LAWRENCE J. SARAKA, WILLIAM M. GOODMAN
Temple University
The purpose of this trip is to instruct participants in the field application of the PAC Hypothesis. Specific objectives include:
1. demonstration of criteria for recognition of PACs in shallow - water carbonate facies of the Manlius Formation;
2. construction of a PAC column by participants at Schoharie N.Y. in the Manlius Formation;
3. observation and evaluation of the stratigraphic section of the Manlius Formation at Thacher Park from an episodic perspective and comparison of those observations to a PAC column constructed by the trip leaders and
4. discussion of the methods, problems and implications of correlation of Manlius PACs between the Thacher Park and Schoharie sections.

A5: CORRELATION OF PUNCTUATED AGGRADATIONAL CYCLES, HELDERBERG GROUP, BETWEEN SCHOHARIE AND THACHER PARK

Large road cut in lower Helderberg Group (STOP 1) on south side of 1-88.

Road cuts in Kalkberg, New Scotland and Becraft fms
Small road cut in Kalkberg Formation on north side of 1-88; large road cut on south side in New Scotland and Becraft Formations.

Small road cut on south side of 1-88 in upper Becraft Oriskany and Esopus Formations.

STOP 1. Brayman, Rondout Manlius and Coeymans Formations
The Cobleskill-Rondout-Manlius interval (85-feet thick) is completely divisible into 13 PACs (fig. 4). The 5 Cobleskill-Rondout PACs comprise a sequence of peritidal cycles initiated and ended by large punctuation events (see water-depth curve). The first of these events followed a sea-level fall which produced the unconformity with the Brayman Shale. After the deposition of 5 PACs, a second large event terminated tidal-flat deposition and initiated a sequence of basically subtidal PACs in the lower Thacher Member of the Manlius Formation. Thus each of these major punctuation events is marked by the introduction of significantly different facies.
Within the sequence of 8 Manlius PACs the boundary between PAC 5 and PAC 6 is unique. At this boundary the upper part of PAC 5 is marked by a laminated cryptalgal crust on a scalloped surface, features which suggest subaerial exposure and erosion resulting from a minor sea-level fall. This surface is a widespread marker horizon traceable throughout the Hudson Valley. The subsequent sea-level rise created water depths sufficient to produce the subtidal bioturbated stromatoporoid-bearing limestones of PAC 6. Another significant punctuation event resulted in even greater water depth and the diversely fossiliferous subtidal facies of PAC 7. PAC 8 is like 7 but is truncated by an unconformity.
The Manlius-Coeymans boundary is a surface with a complex history. At Schoharie, at the top of Manlius PAC 8 (fig. 4), it appears to be a normal PAC boundary marking a major punctuation event which introduced facies very different from Manlius facies below. However, correlation of PACs to the east and south indicate progressive erosion and elimination of PAC 8, 7 and 6 in the Hudson Valley as a result of differential uplift. This erosional surface was then inundated by a sea-level rise which initiated Coeymans deposition throughout the area.
Thus the Cobleskill-Rondout-Manlius interval at Schoharie represents episodic stratigraphic accumulation in response to a complex history of small-scale sea-level fluctuations including 3 sea-level falls and 14 sea-level rises. That each of these events is trUly allogenic and probably eustatic is suggested by correlating each PAC and PAC boundary between Schoharie and Thacher Park (fig. 5).

Quarry in the ManliusCoeymans interval
Quarry in the ManliusCoeymans interval on the south side of road (Rickard Locality 67).

STOP 2. Indian Ladder Staircase, John B. Thacher State Park.
At this locality the Rondout-Manlius-interval consists of 9 PACs, 2 in the Rondout and 7 in the Manlius (fig. 5). The smaller number of Roundout PACs relative to Stop 1 reflects the episodic overstepping of the land mass which was topographically higher at Thacher Park than at Schoharie. Manlius PAC 8 at Thacher Park is absent as a result of pre-Coeymans erosion. Correlation of PACs between the two localities was accomplished by matching unique facies and major facies changes produced by punctuation events. When the columns are correlated by these methods, the number of PACs between major punctuation events is the same at each locality.
Within the Manlius Formation PACs generally consist of facies representing more restricted paleoenvironments than those at Schoharie. For example, PACs 3 and 5 at Thacher Park are capped by a significant thickness of cryptalgal laminites representing aggradation to sea-level. At Schoharie PACs 3 and 5 are capped by shallow subtidal facies reflecting the presence of persistently deeper and less restricted environments at this locality.
Patterns of punctuation events are similar at both localities as interpreted by comparison of facies changes at PAC boundaries. For example a major punctuation event introduced Manlius facies (PAC 1) at both localities; major events also produced marked facies changes at the PAC 3-PAC 4 boundary and at the PAC 6-PAC 7 boundary (fig. 5).
Interpretation of the Manlius-Coeymans Formation boundary as an unconformity at Thacher Park is based on the absence of PAC 8 and on the sharp contact separating markedly disjunct facies. Farther to the south along the Hudson Valley progressively more PACs were eroded as a result of differential uplift of the eastern side of the basin.

A6: STRUCTURE AND ROCK FABRIC WITHIN THE CENTRAL AND SOUTHERN ADIRONDACKS

A7: CAMBRO-ORDOVICIAN SHOALING AND TIDAL DEPOSITS MARGINAL TO IAPETUS OCEAN AND MIDDLE TO UPPER DEVONIAN PERITIDAL DEPOSITS OF THE CATSKILL FAN-DELTAIC COMPLEX
Gerald M. Friedman
Brooklyn College
Rensselaer Center of Applied Geology
Affiliated with Brooklyn College of the
City University of New York
P.O. Box 746, 15 Third Street
This field trip, in which sedimentary facies deposited in Cambrian, Ordovician, and Middle to Upper Devonian shallow-water marine environments will be examined, has been divided into two parts. The first three stops will be devoted to facies of the Cambro-Ordovician period, and the last three will cover the Middle to Upper Devonian facies.

A7: CAMBRO-ORDOVICIAN SHOALING AND TIDAL DEPOSITS MARGINAL TO IAPETUS OCEAN AND MIDDLE TO UPPER DEVONIAN PERITIDAL DEPOSITS OF THE CATSKILL FAN-DELTAIC COMPLEX

STOP 1. Lester Park
PRODUCTS OF INTERTIDAL ENVIRONMENT: DOMED ALGAL MATS (CABBAGE HEADS)
This locality is the site of one of the finest domed algal mats to be seen anywhere preserved in ancient rocks. On the east side of the road in Lester Park a glaciated surface exposes horizontal sections of the cabbage-shaped heads composed of vertically stacked, hemispherical stromatolites (Figure 5). These structures, known as Cryptozoons, have been classically described by James Hall (1847, 1883), Cushing and Ruedemann (1914), and Goldring (1938); an even earlier study drew attention to the presence of ooids as the first reported ooid occurrence in North America (Steele, 1825). Interest in these rocks has been revived as they are useful environmental indicators (Logan, 1961, Fisher, 1965; Halley, 1971). The algal heads are composed of discrete club-shaped or columnar structures built of hemispheroidal stromatolites expanding upward from a base, although continued expansion may result in the fusion of neighboring colonies into a Collenia-type structure (Logan, Rezak, Ginsburg, 1964). The stromatolites are part of the Hoyt Limestone of Late Cambrian (Trempealeauan) age. An intertidal origin has been inferred for these stromatolites (Fig. 6, 7 and 8).
The evidence for deposition under tidal conditions for the Hoyt Limestone at Lester Park includes: (1) mud cracks, (2) flat-pebble conglomerate, (3) small channels, (4) cross-beds, (5) birdseye structures, (6) syngenetic dolomite, and (7) stromatolites (for characteristics on recognition of tidal limestones, see Friedman, 1969).
At Lester Park the heads which are circular in horizontal section range in diameter from one inch to three feet; many are compound heads. The size of the larger heads suggests that they formed in highly turbulent waters.
The line of depositional strike along which the domed stromatolites occur was probably where the waves were breaking as they came across the deeper ocean from the east and impinged on the shelf.
Several petrographic observations in these rocks permit an analogy with modern algal mats in hypersaline pools of the Red Sea Coast (Friedman and others, 1973). Mat-forming algae precipitate radial ooids, oncolites, and grapestones which occur in these rocks; interlaminated calcite and dolomite, which in part compose the stromatolites of the Hoyt Limestone, correspond to alternating aragonite and high-magnesium calcite laminites which modern blue-green algae precipitate. In modern algal mats the high magnesium has been concentrated to form a magnesium-organic complex. Between the magnesium concentration of the high-magnesium calcite and that of the organic matter, sufficient magnesium exists in modern algal laminites to form dolomite. Hence the observation in ancient algal mats, such as observed in the Hoyt Limestone, that calcite and dolomite are interlaminated, with calcite, probably forming at the expense of aragonite and dolomite forming from high-magnesium calcite.

STOP 2. Fort Hunter Quarry
Stromatolites in the Fort Hunter Quarry consist almost entirely of dolomite in the form of irregularly bedded, finely-laminated, undulating structures (Figure 9). The rocks in this quarry are part of the Tribes Hill Formation of earliest Ordovician age (Fisher, 1954). The lithofacies of the Tribes Hill formation have been studied in detail by Braun and Friedman (1969) within the stratigraphic framework established by Fisher (1954). Figure 10 is a columnar section showing the relationship of ten lithofacies to four members of the Tribes Hill Formation. At Fort Hunter we will study the lowermost two lithofacies of the Fort Johnson Member (see column at right (east) end of section, in Fig. 10).
Two lithofacies are observed: (1) lithofacies 1, mottled feldspathic dolomite (Figure 10), and (2) lithofacies 2,. laminated feldspathic dolomite. Lithofacies 1 is at the bottom of the quarry, and lithofacies 2 is approximately halfway up.
Lithofacies 1
This facies occurs as thin dolostone beds, 2 cm to 25 cm but locally more than 50 cm thick, with a few thin interbeds of black argillaceous dolostone which are up to 5 cm thick. In the field, the dolomite shows gray-black mottling and in places birdseye structures. In one sample, the infilling of the birdseyes shows a black bituminous rim which may be anthraxolite. In the field, trace fossils are abundant, but fossils were not noted. Authigenic alkali feldspar (microcline) is ubiquitous throughout this lithofacies; its identity as alkali feldspar was determined by Xray analysis and staining of thin sections with sodium cobaltinitrite. The insoluble residue makes up 22 to 54% by weight of the sediment in samples studied with most of the residue composed of authigenic feldspar. An iron-poor yellow sphalerite may be occasionally found in the rocks of this lithofacies.
This lithofacies is mineralogically identical to the previous facies but differs from it texturally and structurally in being, irregularly bedded and in containing abundant undulating stromatolitic structures ("pseudo-ripples"), as well as disturbed and discontinuous laminae. In places there are a few thin interbeds of black argillaceous dolostone. The thickness of the laminites of this facies ranges from 1/2 mm to 2 or 3 mm; on freshly broken surfaces the color of the thinner laminae is black and that of the thicker ones is gray. The insoluble residue, for the most part composed of authigenic feldspar, constitutes between 35% and 67% by weight in samples studied.
These two lithofacies which form the basal unit of the Ordovician, were formed on a broad shallow shelf. Stromatolites, birdseye structures, scarcity of fossils, bituminous material, syngenetic dolomite, authigenic feldspar, and mottling suggest that these rocks were deposited in a tidal environment (Friedman, 1969). Based on analogy with the carbonate sediments in the modern Bahamas, Braun and Friedman (1969) concluded that these two lithofacies formed under supratidal conditions. However, in the Persian Gulf flat algal mats prefer the uppermost intertidal environment and along the Red Sea coast they flourish where entirely immersed in seawater, provided hypersaline conditions keep away burrowers and grazers (Friedman and others 1973). Hence on this field trip we may conclude that the stromatolites indicate tidal conditions without distinguishing between intertidal and supratidal. For more details on these lithofacies refer to Braun and Friedman (1969).

STOP 3. North Tribes Hill Quarry
Route of Walk
Take the trail toward old abandoned crusher, but instead of heading toward the quarry move uphill to the first rock exposures. The rocks to be examined are near the edge of steep cliff.o
Description and Discussion
In the rocks at this exposure the field relationships show typical channels truncated at their bases. Lodged within the channels are limestone blocks of variable shape ranging in diameter from about one to three feet. These blocks resemble similar blocks in tidal channels of the Bahamas which are derived by undercutting of the banks of the tidal channels. The blocks at this exposure are rounded, suggesting that they have undergone some transport.
The rocks composing the channel (the channel fill) and the blocks of rock within the channels have been described as lithofacies 8 (Figure 11) (channel fill) and lithofacies 7 (Figure 12) (blocks) of the Wolf Hollow Member of the Tribes Hill Formation (lowermost Ordovician) (see columnar section of Fig. 10); column at right end of the section) (Braun and Friedman, 1969). The channel fill (lithofacies 8) consists of intrasparite and biointrasparite with sporadic ooids, a high-energy facies, whereas the blocks (lithofacies 7) consist of mottled dolomitic micrite and biomicrite, a low-energy facies of the undercut bank. The micrite blocks which foundered in the channels must have been indurated penecontemporaneously (Fig. 13).

STOP 4. Marsh Facies
STOP 4. MARSH FACIES
No examples of the marsh facies have been found in situ. However, giant seed ferns of the Gilboa Forest (Goldring, 1924, 1927), which grew in a marsh environment, were discovered in the now-inactive Riverside Quarry near here. More than 200 stumps were taken from this single quarry; some of these have been placed at this site, others are now preserved in museums. The "trees" of Gilboa Forest are among the world's oldest; they grew in a marsh environment of the Catskill Deltaic complex. The bulbous bases of these fossils were found in place in dark-colored shale; the upright trunks were encased in olive-gray, cross-bedded sandstone of probable tidal origin. The age of the "trees" is latest Middle Devonian.

STOP 5. Intertidal Facies: Tidal Flats and Tidal Channels
The rocks at this exposure are medium-gray, fine-grained graywackes; tabular cross-beds are ubiquitous, parting lineations are common. The most interesting single feature at this exposure are the tidal channels. These channels are small, about 2 to 10 feet in cross-section; they truncate the underlying strata. The channel fill consists mostly of a lag concentration of transported spiriferid brachiopod shells (Figure 14). Usually the shell material is abundant enough to rate for the channel the name "coquinite." Holes in the coquinites are brachiopod molds. Interestingly, brachiopod shells are confined only to the coquinite lenses; they are not found in the surrounding rock. Hence the brachiopods were treated by the channels as pebbles that were washed in from the open marine environment. In analogous modern tidal channels, typical open sea species are washed into the channels by flood tides (Van Straaten, 1956).
An alternate interpretation for the coquinite lenses is that they may be storm deposits. The lenses are lag concentrates of brachiopod shells; in the contiguous sandstones pelecypods, chiefly Unio, occur. If these lenticular coquinite lenses were tidal channels,then according to this alternate interpretation, lateral cutting should have concentrated the molluscs. Yet these lenses are devoid of molluscs, hence storms rather than tidal action should have caused the coquinite lenses.
Load-flow structures, formerly known as ball-and-pillow structures, load casts or storm rollers are locally present. They represent compactional differential loading. These structures may be related to slumping and are common on the front of modern deltas.
Note that the next exposure south (uphill) is composed of red fluvial rocks.
This exposure has been described by Johnson and Friedman as part of their section 43 (1969, p. 471-475, especially Figs. 22 and 23). These rocks are the clastic correlatives of the Tully Limestone (early Late Devonian or latest Middle Devonian).

STOP 6. Deposits Of Lagoons And Bars Or Tidal Deltas
At this exposure lenticular sandstone bodies interfinger with dark-gray siltstones and shales. The sandstones have a vertically shingled, or en echelon, configuration relative to one another. Even the thickest sandstone, approximately 6 feet thick, thins and pinches out laterally (see Fig. 25, p. 478 in Johnson and Friedman, 1969). The sandstones contain marine fossils and wood fragments. In places they are crossbedded; ripple marks are locally present. In the siltstones and shales wood fragments are abundant. The presence of marine fossils, the absence of channels, and the lenticular geometric configuration of the sandstones within interfingering siltstones or shales suggests that the sandstones may be bars or tidal deltas. If so, the siltstones or shales are of lagoonal origin.
The rocks at this exposure belong to the Hamilton Group (Middle Devonian) and are about 600 feet below the stratigraphic level of the Tully clastic correlatives.

A8: ROCKS AND PROBLEMS OF THE SOUTHEASTERN ADIRONDACKS
PHILIP R. WHITNEY
Geological Survey, New York State Museum*
Purpose of the Trip
This trip is a roadcut tour of the easternmost fault block of Proterozoic rocks in the Southeastern Adirondacks, and has two major purposes. For beginners in Adirondack geology, the trip will provide an introduction to the major rock types of the area, as well as to many of the characteristic structural features. For the advanced student or professional, the emphasis will be on the numerous unsolved or partially solved problems presented by these extremely complex rocks.
This article is not a report on a finished project, because the writer has not done detailed mapping in the area. The discussion therefore consists largely of preliminary descriptive material, based on a few reconnaissance traverses by the writer and colleagues, plus more detailed examination of the rocks at the scheduled stops, and some very preliminary petrographic work. Previous work in the area includes mapping by Hills (1965) in the southern part of the Pinnacle Range, and by Berry (1961) in the portions of the Whitehall and Putnam quadrangles W and N of the trip area.
Location
The rocks seen on this trip are exposed in roadcuts along Routes 4 and 22 in the Fort Ann and Whitehall 7 1/2 minute quadrangles. They are part of a tilted fault block of Precambrian rocks at the southeastern edge of the Adirondack Highlands, which has been called the Pinnacle Range by Hills (1965). The eastern side of this block is close to the contact with overlying Paleozoic rocks; the unconformity itself is exposed at stop 3.
*Contribution number 462 of the New York State Science Service

A8: ROCKS AND PROBLEMS OF THE SOUTHEASTERN ADIRONDACKS

Outcrops of Cambro-Ordovician Beekmantown carbonates.

Fault block of Precambrian rocks
As you leave the village, notice the range of hills straight ahead. The eastern slope is a dip slope on a fault block of Precambrian rocks (known as the Pinnacle Range) bounded on the west by the Welch Hollow Fault (Hills, 1965). The Paleozoic rocks previously noted are on the downthrown (W) side. This is the easternmost of several such fault blocks, all showing a gentle, regional eastward dip of 10-15° on the Precambrian rocks and overlying paleozoics. The eastern slope of this block is a dip surface close to or at the unconformity, which will be seen in outcrop at stop 3. Is the tilt of this surface a result of a rotation of the fault blocks, or a reflection of the Tertiary-Recent doming of the Adirondacks (Isachsen 1975)?

STOP 1. A plaque on the face of the outcrop
Turn into parking area on R (SE) side of road and cautiously cross road to outcrops on opposite side. A plaque on the face of the outcrop commemorates the Battle of Fort Ann (July 8, 1777). The rocks here are intensely foliated and fractured representatives of the anorthosite suite. Although the characteristic andesine megacrysts found in anorthosites elsewhere in the Adirondacks are absent here, they can be found sporadically in other outcrops along the west side of the Pinnacle Range. Minerals in the anorthosite at this stop consists of recrystallized and sericitized plagioclase, hornblende, clinopyroxene and garnet. Large garnets (please do not sample) are surrounded by leucocratic haloes which locally obliterate the foliation, which suggests that the garnet grew at the expanse of mafic minerals which define the foliation, and that it postdates at least the first deformation.
At the eastern end of the outcrop is a large mass of gabbroic rocks (plagioclase-clinopyroxene- garnet-ilmenite) which displays little or no foliation, and around which the foliation in the anorthositic gneiss is deflected. Also present in the outcrop are a breccia zone and numerous closely spaced fractures with a general northeasterly trend; a major high angle fault may exist roughly parallel to the road.

Coarse marble with amphibolite and gneiss
Outcrops in woods to L of road are coarse marble with numerous detached and rotated blocks of amphibolite and gneiss around which the foliation of the marble is wrapped.

STOP 2. Foliated gneiss with banding and folds
Stop #2. Roadcut on R (SE) side of road. Strongly foliated quartz- 2 feldspar-pyroxene-hornblende-garnet gneisses, ±. biotite. Leucocratic bands contain numerous pyroxene megacrysts, both clino and ortho, the latter showing characteristic rusty weathering color. These rocks are close to the charnockitic end of the migmatitic gray gneiss spectrum. Note the presence of at least two types of amphibolite. One is relatively coarse grained, boudinaged and injected with leucocratic veinlets. The foliation within the boudins is locally truncated by that in the enclosing gneisses. The other amphibolite is dark, fine-grained, biotite-rich, and lacks the leucocratic veining and prominent foliation of the coarser amphibolite. The fine-grained, massive amphibolite forms a megaboudin or recumbent fold (which is it?) near the center of the cut. Do these amphibolites represent one, two, or more generations of mafic intrusives?
Numerous complex minor folds are present within the gneisses; also observe the warping of the foliation by larger, open folds. Measure and record lineations and attempt to relate them to the fold axes of both types. Is more than one lineation present in these rocks?
Thin, folded dark bands near the N end of the cut are a peculiar, fine grained carbonate-rich rock with poorly oriented biotite.

STOP 3. Proterozoic / Paleozoic unconformity
The outcrop on the R side of Rte. 4 just beyond the intersection exposes the unconformity between Proterozoic and Paleozoic rocks (missing: roughly 500 million years of the geologic record, and 20-25 km of Proterozoic rock). The Paleozoic rocks here are coarse arkosic sandstones and quartz-pebble conglomerates of the Cambrian Potsdam Formation, locally with carbonate cement. Measure the strike and dip of the unconformity surface, and compare this with the 10-15° easterly slope of the fault block as observed driving N out of Fort Ann.
Observe the lack of evidence for deep weathering of the Precambrian rocks beneath the contact, and the absence of a paleosol layer. This suggests deep erosion and scouring (by waves? ice?) shortly before deposition of the Potsdam.
Walk a few meters along the S face of the outcrop, towards the canal. Note the complex fracturing of the gneisses, and the filling of the fractures with dark, fine-grained dolomitic rock. The significance of this feature is unclear, and it will be discussed in more detail on the trip. Note the deeply weathered zone where these rocks are exposed at the surface.
After examining the unconformity, cautiously cross the road to the cut in complexly deformed gray gneisses on the opposite side. Measure several lineations here and compare with what you saw at stop #2. Note not only differences in orientation, but also in the nature of the lineation.

Potsdam Sandstone
Outcrops at edge of woods on R are fine-grained white arkosic Potsdam sandstones.

Granitic gneisses close to a NS brittle fault.
Outcrops on L are extensively fractured granitic gneisses close to a NS brittle fault.

STOP 4. Kinzigite and amphibolite
The rocks immediately to the R are strongly foliated biotite-quartz-2 feldspar-garnet gneisses. This version of the gray gneiss is commonly referred to as "kinzigite". Present in this outcrop are thin quartzo-feldspathic pegmatites in various stages of tectonic disintegration and reorientation. The large K-feldspars survive the tearing-apart process better than quartz, and remain visible as large porphyroclasts, either in strings or as isolated individuals. Be alert for evidence of tectonic rotation of these feldspars, which can be a useful indicator of the sense of shear.
Also observe the variable shape and appearance of the garnets: some are rounded and others elliptical: some are nearly inclusion-free while others are "spongy". Careful study of this variation might, if combined with probe analysis of garnet compositions, yield information on the interrelation of metamorphism and deformation of these rocks.
From here, walk northward along the road past a gap in the outcrop, then enter the S end of a long cut. The first rocks are strongly foliated and lineated gray gneisses with lenses and pods of calcsilicates. Roughly 30 m. northward and uphill, these overlie amphibolitic rocks, which comprise most of the remainder of the cut. The bulk of these rocks are strongly foliated garnet amphibolites and mafic gneisses. Numerous lenses and pods of calcsilicates, garnet hornblendite, and ultramafic rocks are present. (Students: the coarse grained ultramafic pods are a fine opportunity to test your mineral recognition skills). About 90 m. northward along the cut a large pod of calcsilicate granulite (grossular-diopside-quartz) is visible in the mafic gneisses on the opposite side of the road. Near the N end of the cut, still on the R (E) side, two large pods or megaboudins of massive, relatively fine grained, garnet-rich metagabbro are surrounded by strongly foliated amphibolites. The transition between foliated and unfoliated rock is very abrupt. Patches of tourmaline- bearing pegmatite are present at the broken(?) end of one of the megaboudins.

STOP 5. Gneisses and Gabbros
Cross the road and walk N along the W side. At the S end are more gray gneisses, here with a distinct reddish tinge caused by an abundance of garnet. The gray gneisses here are nearly devoid of K feldspar. They become more strongly foliated toward the contact with overlying pink granitic gneisses. The contact itself is extremely sharp (but note the late spherical, undeformed garnets, some of which are situated directly on the contact). The pink granitic gneisses, which contain biotite, chlorite and garnet, are strongly foliated, approaching mylonitic texture in places, and display prominent quartz ribbon lineation. The less deformed parts of these gneisses contain K-feldspar megacrysts (phenocrysts? porphyroblasts?) in various stages of deformation and recrystallization.
Continuing N, pass a large gabbro pod, broken at the base and injected with granitic material, in part pegmatitic. Look S across the road; the similarly shaped body of gabbroic rock in the pink gneisses is probably the same pod. Then re-enter gray gneisses, here with somewhat more K feldspar, which is concentrated in the leucosomes. Notice the prominent discontinuity in the foliation which is visible for some distance along the cut. Even though little textural evidence (e.g. grain size reduction) for shear displacement exists along the discontinuity, other explanations for this feature are even more difficult to defend. Toward the N end of the cut is another body of gabbroic rock, which also appears to continue on the opposite side of the road. These mafic rocks, which intrude both the gray and pink gneisses, are generally fine grained and massive with a distinct relict igneous texture. Much garnet is present in the form of indistinct coronas. These rocks are the equivalent of the coronitic olivine metagabbros, a more typical example of which will be seen at stop #8. These gabbroic bodies (several are present here) are lensoid to sigmoidal in cross section but apparently elongated in a roughly N-S direction. Their crudely sigmoidal shape yields opposite estimates of shear sense depending on whether they are pre- or syn-tectonic in origin.
Cross the road to the E side, and note the prominent minor folds in the migmatitic gray gneisses near the N end of the cut. Also note the open, upright folds, which warp the foliation of these rocks, then compare the orientation of these with the recumbent, isoclinal minor folds and with the lineation. Then walk S along the E side and return to the starting point. The petrology of the rocks at this outcrop has been studied in detail by William Glassley and students at Middlebury College. Dr. Glassley (pers. comm. 1985) reports the following:
"Garnet-clinopyroxene and garnet-biotite temperatures were computed from microprobe data. Average temperatures from eight samples ranged from 770 C to 850 C, with a strong mode at 810 C. Pressures, calculated from the assemblages garnet-plagioclase-clinopyroxene-quartz and garnet-plagioclase-orthopyroxene-quartz using the method of Newton and Haselton, averaged 7.5 kb + .5 kb.
"Two unusual assemblages can be found along the contact between the two gneiss units. Within 50 cm of the contact occur 1-3 cm long augen which contain the assemblages clinopyroxene-garnet-rutile and biotite-sillimanite-hercynite-kspar-garnet. The former assemblage is a typical eclogite assemblage. Garnets from these eclogitic lenses are similar to those reported from basal gneiss eclogites in Western Norway. The clinopyroxenes, however, are poor in jadeite component, with only 5% of this component present. The sillimanite- spinel-bearing assemblage is clearly consumed and biotite and sillimanite are being generated. The significance of this assemblage for P-T conditions remains obscure, in that we do not yet have compositional data for all of the minerals in the assemblages nor do we have water fugacity values that would allow calculation of the equilibrium conditions."

STOP 6. (Optional) Paragneiss
The rock here is a pale gray biotite-quartz-2 feldspar-garnet-sillimanite-graphite paragneiss with thin layers and lenses of calcsilicates. Compared to the previously examined "kinzigites", this rock is finer grained, more aluminous, and has distinctive lavender garnets. The abundant white layers look like leucosomes in a migmatite, but they contain significant amounts of sillimanite and are thus probably more aluminous than minimum-melt granite. Note the flattening of the quartz in these layers. Look carefully for lineations defined by sillimanite and quartz.
The protolith of these rocks must have had a significant argillaceous component, as indicated by the presence of both garnet and sillimanite. The lavender-colored garnets are typical of many Adirondack metapelites, a more extreme example of which will be seen at Stop #9.

STOP 7. North end of roadcut.
Pull off road on R and cautiously cross to outcrops at N end of cut on west side; walk S along outcrop. Probably the best way to appreciate these rocks is to move rather rapidly to the S end, scanning the rocks on both sides as you go for major lithologic changes, and then return northward looking at the rocks in detail.
The sequence of rock types going S on the W side is as follows:
A Interlayered (or interleaved?) marbles and paragneisses
B Garnetiferous quartzofeldspathic gneisses intruded by unmetamorphosed mafic dikes
- Gap -
C Charnockitic gneiss
D Thin marble with numerous exotic blocks
E Mafic gneiss
F Calcsilicates and marble
G Interlayered (interleaved?) Paragneiss, charnockite, marble and calcsilicate with amphibolite boudins. An unmetamorphosed mafic dike forms the face of much of this section of the cut.
Details (walking N)
G. Note the wide variety of rock types, including charnockitic gneisses, amphibolites, marble (carefully examine the marble/amphibolite contact), lineated sillimanite bearing metapelites, and calcsilicates. Note the local slickensides along foliation surfaces as well as on vertical fractures. Has there been late movement parallel to the foliation?
F. This thin calcareous unit consists of marble near the base and a complex calcsilicate zone adjacent to the contact with the overlying mafic gneiss. Major minerals in the calcsilicate zone are grossular, diopside, quartz, calcite and K feldspar, with lesser amounts of plagioclase and chlorite as well as several minor phases yet to be identified. Some evidence indicates that wollastonite was initially present but none has yet been positively identified. The calcsilicates probably originated by contact metamorphism at the time of intrusion of the igneous precursor of the overlying mafic gneiss. This contact is irregular and appears to have been folded. The thickness of the calcsilicate layer varies widely, both in this outcrop and on the opposite side of the road.
E. This mafic gneiss contains plagioclase, clinopyroxene, hornblende, biotite, garnet and minor quartz and K feldspar. The composition is probably similar to a monzodiorite. Similar rocks elsewhere in the Adirondacks have been called "jotunite" and are associated with the anorthosite suite of rocks. The rock is well foliated throughout, but becomes more so towards the sharp upper contact. On the opposite (E) side of the road, a detached sliver of the mafic gneiss is found in the overlying marble, and contains carbonate-filled fractures.
D. The next unit upward is a thin (generally < 1 m) band of marble with numerous rotated fragments of other rocks. No calcsilicates are developed near the sharp contact with the mafic gneiss beneath, and the foliation both in the mafic gneiss and in the overlying charnockitic gneiss is strongly developed and parallel to the marble band. In the outcrop on the opposite side of the road, foliation in the charnockite is locally truncated by the marble. This marble is a good example of a possible detachment zone, with relative movement of uncertain direction and magnitude, between the mafic gneiss and the charnockite. The absence of a contact metamorphic zone of calcsilicates at the upper contact of the mafic gneiss may result from its having sheared off during displacement. Alternatively, this marble may be a tectonically emplaced younger rock (see discussion under unit "A", below). Considerable displacement may have taken place along most or all of the marble layers in this outcrop.
C. Above the marble is a thick unit of charnockitic gneiss. This rock, close to granite in composition, consists of quartz, microcline, plagioclase, hornblende, garnet, clinopyroxene and orthopyroxene. The orthopyroxene is extensively chloritized, which is characteristic of many Adirondack charnockites. The typical green color is well developed toward the center of the unit. Near the northern end of the outcrop both green and white varieties are present, with diffuse color boundaries which crosscut foliation.
Immediately beyond the charnockite unit is a gap in the outcrop, possibly indicating the presence of a fault or thick marble layer.
B. Following the gap is a short section of well foliated, garnetiferous quartzofeldspathic gneisses similar to the charnockite but with green color less well developed. Note the unmetamorphosed mafic dike just back from the face of the outcrop, and roughly parallel to it. A few meters farther N is a complex vertical fault with a zone of carbonate-cemented breccia.
A. The last section of the outcrop, roughly 100 m long, consists of interlayered (interleaved?) paragneiss and marble, with minor amphibolite and thin calcsilicate bands in the paragneiss. Contact surfaces are frequently slickensided and/or coated with graphite. At least two types of marble are present; one is dark, relatively fine grained, brown-weathering dolomite marble, which has a slightly fetid odor when struck with a hammer; the other is coarser grained, has a somewhat lighter color and considerable calcite as well as dolomite. Both marbles contain abundant rounded to angular silicate rock and mineral fragments, including quartz, feldspar and serpentine, and larger rotated blocks of various rock types including amphibolites, serpentinite, paragneiss and calcsilicate granulite. Quartz, dolomite and serpentine coexist in these rocks with no evidence of mutual reaction, indicating that the rock as presently constituted has never undergone high temperature metamorphism. Temperatures must have been sufficiently low to prevent reaction of quartz with either dolomite or serpentine. It is probable that these marble zones, as well as those of units G, F and D, are tectonic breccias formed along thrust faults or low-angle normal faults under conditions that permitted the carbonates to recrystallize and deform in ductile fashion, while silicates behaved in a more brittle manner. The interleaved paragneisses, by contrast, are similar to the gray gneisses seen in previous stops, have a high-T metamorphic assemblage and show little evidence of retrogression.
The age of the tectonic interleaving of the gneisses and marbles may be either late Proterozoic or Taconic. The marbles themselves may be Proterozoic with retrograde serpentine after forsterite and entrained fragments of quartz and feldspar, or they may be Paleozoic carbonates with entrained fragments of ultramafic rocks. This question is now under study and will be discussed on the outcrop.

STOP 8. (Optional) Typical Adirondack olivine metagabbros
Stop #8 (Optional). Park as far off the road to the R as possible. Cross with great care to outcrops on the L, and examine them briefly. These are typical Adirondack olivine metagabbros, with well preserved igneous textures as well as coronitic reaction rims around olivine and ilmenite (see introductory section). The interiors of the olivine coronas here have been retrograded to chlorite and carbonate; otherwise the rocks are quite fresh.

Dip-slope on foliation
Flat outcrops on slopes to the L are a dipslope on foliation in highly strained gneisses. A short distance N, on West Mtn., a mylonite zone close to 300 m thick is exposed. The hills across the valley to the R, and on Skene Mtn. straight ahead, are Cambro- Ordovician carbonates of the Whitehall Formation, resting on Potsdam sandstone.

STOP 9. Typical metapelites
Pull off road to R close to smaller outcrop, and cross to larger cut on L. The rocks here are typical metapelites, consisting of quartz, K feldspar, sillimanite, lavender garnet and varying amounts of biotite and graphite.

Entering series of cuts in highly fractured metasedimentary rocks.

STOP 10. Abandoned Quartzite Quarry
Entrance to abandoned quarry and Washington County Highway Dept. Garage. This is posted private property; if following this road log on your own, ask permission at large brick farmhouse 0.2 miles further along road on R. Be extremely careful climbing and hammering here - there is much loose rock and the quartzite is very splintery when hammered.
This thick unit of quartzite is interlayered with lesser amounts of a greenish rock which forms bands and streaks from a fraction of a millimeter up to several tens of centimeters thick, with knife sharp contacts against the quartzite.
The quartzite, which is visibly foliated in hand specimen, comprises over 95% of strongly flattened quartz; small, flattened and elongated grains of K feldspar and sericitized plagioclase, lensoid garnets, green biotite and chlorite. The interlayered green rock ranges from plagioclase-quartz-garnet-biotite-hypersthene gneiss to a retrograded epidote-chlorite-quartz-plagioclase rock with some muscovite and at least two minerals yet to be identified. Some well crystallized chlorite is present as flakes parallel to the foliation, but chlorite also occurs locally as an alteration product of garnet. Distribution of the retrograde assemblage within the outcrop has not been determined. If it is related to fracture patterns, it may be low temperature alteration along the E-W brittle fault which parallels the road. If not, it may be evidence for localized retrogression associated with renewed, layer- parallel shearing during the latest Proterozoic or during the Taconic event. Supporting the latter hypothesis are slickensides on foliation surfaces at an acute angle to the lineation.
All rocks at this site show extreme foliation and a well developed lineation, here close to E-W, with a 0-20° E plunge. Numerous minor folds are present. These are of two distinct types, both of which are recumbent with axes parallel to the lineation. One type consists of intrafolial, highly asymmetric, isoclinal folds defined by thin micaceous layers in the quartzite. Among folds of this type is an apparent sheath fold strongly flattened in the plane of foliation. The other type is not quite isoclinal, more symmetric, and visibly folds the foliation in the quartzite. The minor folds and petrofabrics at this outcrop have been described by Granath and Barstow (1980), who attribute the deformation primarily to a severe flattening strain.

Fault bounded block
Crossing South Bay on Lake Champlain. The rocks underlying the valley to the North are Paleozoic strata downdropped along a major normal fault which here forms the western side of the Pinnacle Range.
Toward the south, this fault intersects the Welch Hollow fault at an oblique angle. The fault follows the shore of South Bay south of the bridge, then strikes inland and follows the line of cliffs visible to the north. Estimated vertical displacement on this fault based on offset of Paleozoic cover rocks is in the vicinity of 300 m. West of the bay, outcrops of gently E-dipping, highly deformed Precambrian rocks resume.

A9: CAMBRIAN AND ORDOVICIAN PLATFORM SEDIMENTATION - SOUTHERN LAKE CHAMPLAIN VALLEY
Bruce Selleck
Brewster Baldwin
Middlebury College
The Cambrian-Medial Ordovician strata of the southern Lake Champlain Valley record the evolution and demise of passive margin sedimentation on the North American coast of the proto-Atlantic Ocean. The goals of our trip are to examine exposures of key units in this stratigraphy, interpret the depositional environments represented and consider the possible tectonic controls over the history of platform sedimentation during the early Paleozoic in eastern North America.
Our trip will focus on two sections of the stratigraphy: (1) the Late Cambrian Ticonderoga Dolostone and basal Whitehall Formation and (2) the Medial Ordovician Chazy, Black River and Trenton Groups. The general area of interest (Fig. 1) lies within the Ticonderoga and Port Henry, N.Y. 151 Quadrangles.

STOP 1A. Ticonderoga Dolostone
Relatively new roadcuts on Shore Airport Road provide excellent exposures of portions of the Ticonderoga Dolostone and Whitehall Formation. The generalized stratigraphy of this series of outcrops is presented on the following pages. Stop 1A is wholly within the Ticonderoga Dolostone; lB is uppermost Ticonderoga Dolostone or basal Whitehall (Finch Dolostone of Fisher, 1984) Formation; Stop lC is clearly Whitehall Formation, Finch Dolostone Member. We will walk upsection from the base of Stop 1A to Stop 1B, reboard the bus to Stop 1C. Please watch for cars!
A series of normal faults juxtapose blocks containing various sections of the Cambro-Ordovician stratigraphy in the Ticonderoga area. To our southwest, Proterozoic marbles and gneiss hold up Prospect Mountain. The village of Ticonderoga largely sits upon Potsdam Sandstone (Keeseville Member). To our south and east, the younger formations of the Beekmantown Group are exposed in the vicinity of Fort Ticonderoga. At this stop approximately 20 meters of Ticonderoga Dolostone is exposed. The basal 2/3 of the outcrop consists of 0.2 - 1.0 meter units of bioturbated sandy dolostone interbedded with 0.1-1.0 meter units of cross-stratified slightly dolomitic medium to fine sandstones. Rare prism cracks in the fine silty dolostones document sporadic subaerial exposure. "Herringbone" cross-strata, reactivation surfaces and shear-deformed cross-strata are well-exposed on weathered surfaces of the sandstones. Poorly preserved specimens of the gastropod Ophileta sp. are found on the bedding surface of a dolomitic sandstone approx. 8 meters from the base of the section. R. Linsley (personal communication) has suggested that Ophileta, was a relatively sedentary grazer or deposit feeder. The upper 1/3 of the section contains relatively more abundant prism cracks, shaly interbeds and intraclast breccia horizons, perhaps indicating more regular subaerial exposure.
The rhythmically interbedded bioturbated dolostones and cross-stratified dolomitic sandstones are interpreted as high and low tidal flat/shallow subtidal facies, respectively. Carbonate mud and terrigenous sands deposited on a relatively low energy upper intertidal flat provided a suitable habitat for burrowing infaunal organisms. The lower tidal flat and shallow subtidal environment was characterized by more vigorous current action which limited faunal activity and produced cross-strata and associated structures. The repetitive interbedding of these facies suggests repetitive progradation of burrowed sandy muds over current-bedded sands. The upsection decrease in current-produced structures and increasing evidence of exposure indicates an overall shallowing up trend in the Ticonderoga Dolostone at this locality.

STOP 1B. North side of Shore Airport Road, 150 m from STOP 1A
This outcrop exposes about 7 m of silty, cherty dolostones assignable to either the uppermost Ticonderoga Dolostone or the basal Finch Member of the Whitehall Formation. The pervasive dolomitization plus outcrop weathering have obscured the primary structures and fabrics. The lower approx. 1 meter consists of laminated silty dolostones with ripple cross-lamination and thin intraclastic horizons. The succeeding 1.5 meters consists of thick-bedded to massive coarsely crystalline dolostone containing calcite-filled voids of various sizes. The succeeding 2 meters consists of bioturbated, dark medium crystalline dolostone with vaguely developed digitate algal (?) structures. Laminated, finely crystalline dolostones follow, capped by dolostones with algal mounds. In the upper 1 1/2 m of the outcrop, cherty, laminated dolostones apparently drape an irregular algal mound (thrombolites) surface. Note laminated silty dolostone between algal mounds.
The lack of diagnostic fossils and primary structures in these lithologies make environmental assignment difficult. If the digitate algal structures and cryptalgal laminites are indeed present, a shallow subtidal to low intertidal environment may be inferred. Bioturbated dolostones could be of intertidal or more offshore origin. Any suggestions?? (We will reboard bus at this point and continue east on Shore Airport Road 400 meters to Stop 1 C.)

STOP 1C. Outcrop on north side of road, 400 m from STOP 1B
Approximately 3 1/2 meters of the Finch Dolostone Member of the Whitehall Formation is exposed at this stop. Three facies occur in a somewhat repetitive fashion: (A) Coarsely crystalline, laminated to slightly bioturbated dolostone (dolomitizad grainstone); (B) "pin-stripe" laminated cherty finely crystalline dolostone with rare burrows; and (C) dark grey to black dolomitic chert with dolomitized molluscan debris and dolomitic digitate algal stromatolites and dolomite "knots" (small algal structures??). The uppermost dolomitic chert bed thickens and thins on outcrop scale. The thicker portions of this bed appears to represent local "domes" or mounds formed by the thrombolites or algal stromatolites. Gastropod debris can be seen in one mound, perhaps representing shell material collected between cylindrical algal pillars.
The absence of direct evidence of subaerial exposure again makes exact environmental assignment quite equivocal. We suggest that the coarsely crystalline dolostones represent a "high energy" shallow subtidal/low intertidal facies; the "pin stripe" laminites a relatively lower energy muddy tidal flat facies. The dolomitic chert facies containing algal structures is probably shallow subtidal. We are again open to suggestions.
The origin of the silica for chertification of these rocks is also something of a problem. Rubin (1975) suggested that subaerial "silcretization" involving dissolution of terrigenous silicates and precipitation of opaline silica or quartz in a pedogenic setting on emergent tidal flats was a factor in chertification of Whitehall Formation carbonates. The fabrics indicating pedogenic silicification reported by Rubin are not present at this locality, however. A possible alternative is fabric-selective replacement of primary carbonate mud by silica derived from a biogenic source (sponge spicules) within the original sediment.

STOP 2A. Outpost fort east of N.Y. 8
Approximately 6 meters of variously burrowed, slightly dolomitic, thin to medium bedded bioclastic packstones are exposein this section. The dolomite occurs in shaly weathering wisps and laminae and in burrow fills. Abundant "Girvanella" algal oncolites (algal accretionary grains) are present in beds approx. 4 meters from the base of the section. Rounded dark calcite grains (abraded gastropod fragments) form the cores of the oncolites, and are scattered in other beds. Fossils are relatively abundant and best seen on bedding surfaces. Trilobite fragments, brachiopods, bryozoans, pelmatozoan plates, nautiloids and large Maclurites magnus are present. The relatively high faunal diversity, abundant lime mud and burrowing argue for a normal marine, low energy shallow subtidal carbonate environment. A possible modern analogue is found in the mixed mud and sand shelf to the west of the emergent Andros Island tidal flats, as described by Bathurst (1971) and Purdy (1963). The 5-10 cm thick beds of "oncolite conglomerate" and other more well-sorted grainstone beds may represent periods of storm winnowing of the bottom, with transportation of abraded sand from adjacent sand shoal environments (e.g. Locality 2B). The wavy, irregular dolomite laminae appear to result from post-depositional dolomitization of lime mud, followed by compaction and local pressure solution of calcite, producing irregular, clay- and dolomite-rich stylocumulate seams. Preferential dolomitization of burrows may be due to contrasts in porosity or permeability of burrow-fill versus burrow-matrix sediment. The burrow-fill sediment may have retained permeability longer during diagenesis, permitting pervasive dolomitization. This sort of fabric selective dolomitization is common throughout the Chazy and Black River Groups in the southern Lake Champlain Valley.

STOP 2B. Ledge immediately NE of gate to Historic Site
Cross-stratified coarse lime grainstones with bipolar crossbed dip directions are well-exposed near the entrance road. Siliciclastic sand grains (angular quartz and feldspar up to 2 mm in diameter) are locally concentrated along prominent stylolite seams. The carbonate particles are dominately subrounded, abraded pelmatozoan plates, plus gastropod and brachiopod fragments. Large Maclurites fragments and grainstone intraclasts are present on the upper bedding plane surfaces of the ledge.
We envision the environment of deposition of this facies as shallow subtidal wave and/or current reworked sand bars. Active transport of abraded grains may have been accomplished by tidal currents as suggested by the bipolar cross-beds. The lack of burrows and well-preserved fossils may be due to the inhospitable shifting sand substrate. This environment may have been rather like the unstable sand shoal environments described from the Bahamas Platform by Bathurst (1971) and Ball (1967). The scale and style of cross-stratification present here are similar to that predicted by Ball from his studies of the bed forms and primary structures of the Bahamian sand bodies. Similar Chazyan facies in the Northern Champlain Valley contain abundant oolites (Oxley and Kay, 1959).

STOP 2C. Low Ledges on entrance road approx. 50 meters north of 2B
Brown weathering, slightly shaley dolostone exposed here contains small lenses and stringers of fossiliferous lime packestone. Trilobites, small brachiopods and Maclurites fragments are common. This exposure resembles the shelf lagoon facies of Stop 2A, although dolomitization is more pervasive.

STOP 2D. East point of British Fort, by horizontal water tank and south moat
Approximately 3 meters of thickly laminated limestone and dolostone is exposed in the southeast "moat" of the British Fort. The dominant facies here consists of alternating 0.5-2 cm thick laminae of limestone and dolostone - often termed a "ribbon rock". The limestone ribbons are mudstones and appear blue-grey on slightly weathered surfaces and as indentations on highly weathered surfaces. The more resistant dolostone weathers tan to brown. An erosional surface with 10-20 cm of relief is exposed near the base of the southwall. Abundant Maclurites shells occur in a shell bed on this surface. Lateral accretion cross-strata consisting of gently dipping ribbon rock are present above the erosional surface. Dolomitized burrows transect the limestone ribbons in the lower 1 meter of the section. On the less-weathered prominence on the SE corner of the moat, shallow scours containing a shell hash of brachiopods and gastropod debris are present, along with intraclasts of lime mudstone in dolostone and "Mexican Hat" structures (rolled intraclasts or pseudoclasts with a dolomitized burrow center).
We interpret this sequence as a tidal flat facies. The rhythmic limestone/dolostone "ribbon" fabric is interpreted as representing alternating slightly finer (lime mudstone) and coarser (dolostone) "tidal bedding" similar to that described by Reineck and Singh (1980) from the clastic mud/sand tidal flats of the North Sea. The Maclurites shell bed may mark the basal erosional level of a tidal channel, with the cross-stratified ribbon laminites forming by draping on the channelled surface. Variations in degree of burrowing record subtle differences in degree of subaerial exposure of the flat and/or reworking by tidal currents. Limited in situ faunal diversity is also expected in the stressed tidal flat environments. The absence of mudcracks and any indication of evaporite minerals suggests that we are seeing only the lower portion of a wet intertidal flat system preserved here.

STOP 2E. Enter Parade Grounds by barracks.
Around 1916, gunite was sprayed on the interior walls to protect the mortar from deteriorating. Starting in 1976, the N.Y. State Division for Historic Preservation began extensive maintenance, removing loose gunite, replacing rotted stones and repainting the stone walls.
In the outer wall of the first barracks, note at about eye level the stones that are nearly white-weathering. These are lime mudstones from the "Lowville" facies of the Orwell Limestone, exposed at Stop 2F.
The broad limestone outcrop west of the barracks is a cross-stratified lime grainstone with scattered subrounded quartz and feldspar sand grains. Trough cross-strata and "herringbone" co-sets of planar-tabular cross-strata are visible on the low vertical face. Large angular clasts of slightly dolomitic lime grainstones and Maclurites magnus shells are present on the uppermost bedding surfaces.
We interpret this facies as a current-dominated sand shoal environment rather similar to the exposures at Stop 2B.
Westward across the parade grounds there is a massive, bioturbated, brown weathering dolostone unit (similar to Stop 2C), overlain by 0.5 meters of very coarse-grained bioturbated, slightly dolomitic feldspathic quartz sandstone. This sandstone forms the summit of the Chazy Group (Crown Point Formation). The abundant angular quartz and feldspar granules in the sandstone suggest derivation from a relatively close granitic (Adirondack?) source terrane. These sands were apparently transported from the west during an interval of relative emergence of the carbonate platform and were briefly reworked in a shallow marine setting. The basal dolostone bed of the Black River is exposed immediately atop the sandstone.

STOP 2F - Moat Walls at North Entrance to British Fort
The section from here to locality I is within the Orwell Limestone. The basal beds consists of thick-bedded to massive lime mudstones with vertical spar-filled burrows (form - genus Phytopsis) and rare ostracodes. Fossil abundance and diversity increase in the overlying beds, with gastropods (Loxoplocus), corals (Lambeophyllum, Foerstephyllum) and brachiopods appearing. Grain size increases upsection, with sporadic appearance of intraclast grainstones and ripple cross-lamination. Overall this section is similar to the Lowville Limestone of the type Black River Group of the Tug Hill region. The facies pattern here suggests a progression from restricted (tidal or lagoonal?) mud flats (Phytopsis lime mudstones) to more open marine mixed mud/sand shelf environments.
The summit of the moat outcrop exposes a horizon of black chert nodules which can be traced laterally across the road to locality G.

Stop 2G. Ledges extending from service road to lake shore.
Watch for poison ivy!
These exposures closely resemble the Chaumont (House Creek Limestone of Fisher, 1977) facies of the Black River type section. Thick-bedded to massive richly fossiliferous lime packstones and wackestones document a normal marine, relatively low energy carbonate shelf environment. In addition to the forms mentioned earlier, the large stromatoporoid (calcisponge) Stromatocerium, the high-spired gastropods Hormotoma and Subulites, the nautiloids Actinoceras and Geisonoceras, plus bryozoans, brachiopods and pelmatozoan material are common. On some bedding surfaces, black chert nodules follow large horizontal burrows. The chertification here is post-depositional and involved dissolution and reprecipitation of siliceous skeletal material (sponge and radiolarian). The uppermost bed in this set of ledges is a black chert bed approximately 2 cms thick. This bed can be traced to the lake shore where a similar section can be seen. Glacial abrasion obscures much of the detail that is exposed on more weathered surfaces.

STOP 2H. Blocks and Quarry Walls by Lake Shore
The quarry was established in 1870 by the Fletcher Marble Co. in an unsuccessful attempt to find a source of "black marble" dimension stone. The quarry is reportedly only 1 meter or so deep. The narrow spit going north was built to load blocks on barges, but evidently no blocks were shipped. The quarried blocks consist of medium to thick-bedded fossiliferous packstones and wackestones with some ripple cross-laminated grainstone beds visible in the north quarry bench. Strophomenid brachiopods, bryozoans, pelmatozoan stems and fragments of the trilobite Isotelus are present. The environments represented here are similar to those at 2G. As we continue north and walk along the lake shore, more exposures of the upper part of the Orwell can be examined. The bedding surfaces contain abundant opercula of Maclurites logani, and scattered Forstephyllum, Lambeophyllum and Stromatocerium are found. The byssate bivalve Ambonychi is also present.
The transition from the Orwell to overlying Glens Falls Limestone is covered by beach gravels as we continue west along the lake shore.

STOP 2I. Exposures of Glens Falls ls separated by intervals of beach gravels
Stops 2I ,J, ad K - Series of exposures of Glens Falls Limestone separated by covered intervals of beach gravels
The westernmost outcrops are on Private Property beyond Locality K. Do not go onto that part of the shore (marked by fence and stone wall, plus the large dead elm tree).
The Glens Falls limestone consists of medium to thin-bedded lime packstones and wackestones with some well-laminated, fine-grained bioclastic grainstones. Many limestone beds show internal grading from coarse, fossil-rich bases to less fossiliferous, fine-grained tops. Thin shaley interbeds separate the limestone beds. Horizontal trails and burrows (including form-genus Chondrites) are common on some bedding surfaces.
Fossils are abundant and rather diverse. Trilobites (usually fragmental) include Isotelus, Flexicalymene and rare Cryptolithus; the brachiopods Sowerbyella, Rafinesquina, Dinorthis and Dalmanella; bryozoans Prasopora, Eridotrypa and Stictopora; plus orthocone cephalopods and pelmatozoan debris. Gastropods, which are so abundant in the underlying Orwell limestone are exceedingly rare in the Glens Falls.
The environment of deposition for the Glens Falls is a sub-wave base shelf. No shallow water features are observed and the graded limestone beds are evidently deposited by density/turbidity currents generated on adjacent, slightly shallower portions of the shelf. The Glens Falls here records the continuing deepening of the Middle Ordovician shelf that began with the deposition of the Phytopsis lime mudstones at Stop 2F. The shale interbeds and generally more argillaceous character of the Glens Falls document increase in terrigenous mud input, perhaps derived from the rising Taconic Orogenic complex to the east. Quartz and feldspar grains of volcanic origin are also common in insoluble residues of Glens Falls limestones, suggesting increased eruptive activity at this time.
The contrast in terrigenous content of the Chazy Group vs. Black River and Trenton Groups is noteworthy. Insoluble residues from Chazy Group carbonates contain abundant, coarse-grained, rather angular quartz and feldspar grains (e.g. Stops 2B and 2D) plus clay-size material whereas the Black River and Trenton Groups lack coarse sand-size grains and contain either volcanic quartz and feldspar (Black River and Trenton Groups) or clay plus volcanics (Trenton Group). This change is likely related to a shift in available clastic source from the slightly emergent cratonic basement to the west that was exposed during Chazy Group deposition to the rising Taconic volcanic/metamorphic complex to the east during Black River-Trenton Deposition.
Combining the environments of deposition with the time-thickness pattern of sedimentation, the Crown Point section takes on tectonic meaning. The Chazy sediments were deposited just about at sea level -- Girvanella and Maclurites. The Orwell was deposited in shallow sub-tidal conditions -- two corals, the grazing snail Maclurites, and probably the Stromatocerium. The Glens Falls was deposited in a more offshore setting.
A time-thickness graph for the Cambrian-Ordovician sequence of the Champlain Lowlands shows some interesting changes in slope. Sedimentation through the Chazy yields a concave-upward curve that shows a continued slowing of crustal subsidence. Then, starting with the Orwell, the crustal subsidence is greater than the rate of sedimentation, because the water deepens. Using the Middle Ordovician time scale of Churkin and others (1977), it is clear that Chazy sedimentation was scarcely 5 m/m.y.; the Orwell and Glens Falls accumulated at 30 or 40 m/m.y., and the thick shales accumulated at 200 m/m.y. (solid-grain thickness). This high rate is comparable to the rate of subsidence of the Australian platform entering the Timor trench (600 m/m.y.; Baldwin, 1982).
The Crown Point section, then, fits the picture of a cooling and slowly subsiding continental margin, through Chazy time. Then, the margin began collapsing as it tried to enter a subduction zone to the east, causing water to deepen rapidly. The section is a record of the very early part of the Taconic Orogeny, as the "east-moving proto-North American Plate 'felt' the presence of an approaching island arc" (Baldwin, 1982). collision that constitutes the Taconic orogeny.

A10: GLACIAL GEOLOGY AND HISTORY OF THE NORTHERN HUDSON BASIN, NEW YORK AND VERMONT
DAVID J. DE SIMONE
Department of Geology, Rensselaer Polytechnic Institute
Troy, New York 12180-3590
ROBERT G. LA FLEUR

A10: GLACIAL GEOLOGY AND HISTORY OF THE NORTHERN HUDSON BASIN, NEW YORK AND VERMONT

Ahead is the Batten Kill delta (310-320 ft Lake Quaker Springs).

NY 29 climbs the foreslope of the delta
NY 29 climbs the foreslope of the delta approximately along the axis of maximum thickness of gravel and sand. The banks along the road reveal the coarsening-up stratigraphy.

Water well logs record up to 65 ft of deltaic gravel and sand in the area.

STOP 1: Hollingsworth-Vose landfill.
Deltaic topset and foreset beds of the Batten Kill's Quaker Springs delta.

Deltaic gravel and sand, lake clay, and lodgement till are exposed.

Sediment thins rapidly southward
Water well logs and exposures indicate deltaic sediment thins rapidly southward through 30 ft to less than 10 ft. Notice the clay dug up from the pond farther along the road.

Groundwater flows out along the SG-clay contact
Groundwater flows out along the SG-clay contact at the heads of these gullies in Fryer Brook. We observed a pipe with a diameter just right for your arm at the head of one gully in 1977.

Notice the clay gullies as Wilbur Ave. crosses Fryer Brook.

Traversing the dissected clay plain and delta sand is gone
We're traversing the dissected clay plain and delta sand is gone so we cross Flately Brook and turn to the E.

Observe the shoreline profile of Lake Quaker Springs.
No beach sediment is preserved.

Till on your left and the lake clay plain on your right
Till on your left and the lake clay plain on your right with the tops of a few drumlins poking through.

Outwash fan into Lake Albany.
Meltwater flowed between Schuyler and Whelden mountains and deposited an outwash fan into Lake Albany. Minor exposures along the stream to your right (S) reveal gravel overlying clay and basal lodgement till.

STOP 2: Archdale kame moraine.
Exposure of clinoform sand and gravel beds in the moraine. Minor slumping of beds.

STOP 3: Nessle Bros Meats parking lot.
An excellent overview of the Archdale kame moraine deposited against the flank of Herrington Hill. This kame moraine band can be traced southward along the west side of Fly Swamp and across the valley at the southern end of the swamp where a head of outwash is recognized. Return N on WC 74.

Terrace-outwash gravel and sand
Note the terrace-outwash gravel and sand we're crossing with thin till and bedrock uplands to the north. At small rises and around curves in NY 29 till and bedrock are often exposed where the upland thin till and bedrock topography protrudes through the gravel and sand.

Old excavation into a kame ahead on your left.
Note the old excavation into a kame ahead on your left. This is associated with the Battenville moraine.

There is hummocky kamic gravel and sand ahead on your left.
NY 29 used up the till and gravel of the Battenville moraine where the moraine crosses the valley in Battenville.

Flat outwash and terrace gravel and sand
The fairly flat outwash and terrace gravel and sand we're crossing was deposited by meltwater from the ice margin

STOP 4: Tracy Bros excavation.
Horizontally-stratified gravel and sand overlies cross-stratified gravel and sand. Meltwater from the Carter Swamp ice margin deposited this deltaic sediment with sediment sources from the N and E. The Batten Kill has terraced the S end of this deposit.

STOP 5: Lodgement till exposure N side of NY 29.
Both lowland and highland lodgement till facies are similar in Washington County. Why? In contrast, the lodgement till of the Adirondacks is quite different from the Hudson lowland till.

A thick graded gravel bed was observed.
There is an excavation just to your right off of Ferguson Rd where a thick graded gravel bed was observed. How would you describe the sedimentary environment which produced this feature?

Notice the hummocky ice marginal sediment on your left.

Carter's Pond Wildlife Management Area. Lunch Stop.

Smooth rounded drumlinoid topography
Notice the smooth rounded drumlinoid topography developed in these thinly-veneered bedrock highlands.

Argyle sits atop a modest esker delta
The village of Argyle sits atop a modest esker delta deposited into Lake Quaker Springs. Lake clay nearly buried the delta.

STOP 6: Esker gravel and lake clay.
NY 40 rides atop this esker which fed the Argyle delta. Lacustrine clay has partly, and in places completely, buried the esker gravel and sand. Observe the deformed clay and gravel beds here. Is the deformation consistent with what you'd expect from melt-out of buried and/or adjacent ice or would you suggest a minor ice surge after deposition of the clay to account for the stratigraphy? Continue N on NY 40 along the crest of the esker.

STOP 7: Meltwater sediment complex
Harrington Farm excavations expose part of a meltwater sediment complex deposited at the base of the Taconic front along the eastern edge of Tamarack Swamp. The ice tongue responsible for the esker and delta through North Argyle and Argyle stagnated in the swamp. The major meltwater source for this sediment can be traced eastward along Safford Rd. to the town landfill. Coarser gravel and sand, horizontally-bedded and cross stratified, is exposed east of the road. The more distal portion of the delta fan exposed here contains laminated and ripple-laminated sand. A third excavation to the SW in the middle of the swamp contains the most distal and finest-grained sand, silt, and clay beds. The morphology of this last deposit suggests deposition in a tunnel or crevasse in the ice and indicates the rotting ice in Tamarack Swamp was inundated by Lake Quaker Springs.

STOP 8: Outwash gravel and sand in a significant local impoundment.
The north-flowing Mettawee River deposited this outwash gravel and sand in a significant local impondment. The exposed sand, silt, and clay beds accumulated in this Lake Granville whose elevation was approximately 420 ft. Clay is also preserved in the Mettawee valley from Middle Granville westward to Truthville with more silty sediment north of Raceville. There are some concretions in the clay here. Mildly deformed sediment particularly at the north end of the exposure probably resulted from meltout of abandoned ice in the lake. The Hudson ice lobe probably blocked the lower Mettawee valley at Truthville and contained Lake Granville. Retreat of this ice drained the lake and the Mettawee. River deposited its delta into Lake Quaker Springs.

This surface is the top of the Mettawee delta.

STOP 9: Winchell channel overlook.
Park as far off the road as possible and be careful of the traffic! The Winchell channel was one of three channels (the Durkeetown and Ft. Edward are the other two) which carried the outflow of Lake Fort Ann in the Champlain valley through the northern Hudson valley. The present surface stream, Big or Mill Creek, enters the channel from the south through a bedrock gorge (seen as a notch in the distance) and meanders across the channel bottom to Smith's Basin. The channel bottom consists primarily of lake clay while clay, till, and bedrock are all exposed on the flanks of the Winchell channel. This pattern generally holds for the other two channels as well except there is considerably more eroded bedrock along the primary Ft. Edward channel.

Bottom of the broad Durkeetown channel
We're crossing the bottom of the broad Durkeetown channel and will climb up its western escarpment. North-flowing Wood Creek and south-flowing Dead Creek are underfit streams in the bottom of the channel.

We're descending into the Ft. Edward channel.

The canal follows the bottom of the Ft. Edward channel.
Hudson-Champlain canal crossing - the canal follows the bottom of the Ft. Edward channel.

B1: THE NATURE OF THE EASTERN TACONIC CONTACT
PHILIP C. HEWITT
Department of the Earth Sciences
SUNY College at Brockport
Brockport, NY 14420
The purpose of this paper is to provide background information needed for both the full-day trip (A1) and the half-day trip (B1). The full day trip involves data from the entire paper while the half-day trip concentrates on the Taconic Problem primarily. However, to understand either day fully, the entire paper must be read. A separate Road Log for each trip is provided at the end of the paper.
The paper describes geologic features to be examined in area from Saratoga Springs, N.Y. to Manchester, Vt. A discussion and overview of the Taconic region and the "Taconic Problem" will be presented. Consideration will be given to both the sequential and fault hypotheses proposed for the High Taconic region.
The Taconic region is subdivided into the High Taconics and the Low Taconics based on the extreme difference in relief. The High Taconics are the mountains of Vermont, west of the Vermont Valley, with elevations of approximately 3000-4000 ft. The Low Taconics are the hills primarily in New York, west of the High Taconics, with elevations up to approximately 1500 ft. (Hewitt, 1961a). Lithologic and other distinctions will become apparent in the later discussion.

B1: THE NATURE OF THE EASTERN TACONIC CONTACT

STOP 1. Carbonate-Phyllite Contact At Sandgate
The exposure of green phyllite at this locality lies at the axis of a large anticline that lifts the base of the formation structurally. With favorable topography the lower parts of a formation may be exposed as at this locality. In a synclinorium, it is normal to expect that generally, the higher parts of the formations will lie deeper in the earth. When an anticline fortuitously is cut by erosion to expose lower and lower parts of a formation more data become available. In this case, part of the phyllite section responds to hydrochloric acid in a formation that normally has no calcareous beds.
After a general examination of the exposure a study of the lowest part of the formation visible here should be undertaken. This part is located at the southeast end of the outcrop. Note that the base of the exposure appears to be phyllitic and very much like the rest of the rocks here. If cold, dilute hydrochloric acid is applied, the lowest beds will effervesce. Visually one cannot see a difference between those beds that will react with the acid and those that will not. The question that must be asked is "What does this mean?" No other part of the phyllite reacts with acid. Carbonates are known to lie under the phyllite. Therefore, this is probably the contact of the carbonate and green phyllite. The nature of that contact at this locality is for you to decide.
Note also the depression to the south of this outcrop. Two possibilities exist here. The depression may be a combination of structure and topography. That is, the depression might lie in a syncline and therefore lower as a result of structure. This does not appear to be the case here because the anticline passes across the depression. It is also possible that the depression is the result of weathering of a carbonate exposed at the base of the phyllite. Return to cars and proceed southward.

Note folding along road.

STOP 2. Cook Hollow-Exposure Of Contact
It is wise, politic and intelligent to request permission to cross the property here to make the climb. The climb will involve a rise of 1200- 1400 ft. in elevation. Caution is important. Parts of the climb are steep. Some parts are slippery. A slow, steady climb with frequent stops is the best way to see the outcrops and arrive at the contact safely.
Each of the formations mentioned are described briefly in Table 1.
The drive from Rt. 7 crossed the upper Cambrian Danby quartzite and Clarendon Springs formation both of which contain quartzite and dolostone. These formations are not exposed along that traverse. After leaving the cars the traverse begins in the Shelburne marble. Exposures of these strata are best in the creek south of the traverse. It is best to begin the traverse by approaching the creek in order to examine the beds during the climb. However, higher parts of the climb may be difficult or nearly impossible in the creek since this is a landslide area. The easiest climb is on the north (right) side of the creek.
The contact of the Shelburne marble with the overlying Bascom-Beldens formation is at Table Rock. White marble, similar to that of the commercial marble in the Shelburne is also found in the Bascom-Beldens. However, most of the Bascom-Beldens formation is dolomitic marble which is blue-gray to black in color. Near the top of the dolomitic sequence, several hundred feet below the contact with the green phyllite are fossiliferous beds in the marble which contain fossils identical to those at the Covered Bridge on Rt. 313. These indicate an age of medial Ordovician (Trentonian). Beds containing fossils continue across the sequence almost to the contact.
Continued climb will reach a zone of carbonate and phyllite interbeds. Above this zone is a flat area or bench with the contact easily visible. Carbonate ends and the green phyllite continues to the top of Mt. Equinox.
No further description will be presented. It is up to the observer to decide what is seen here. Is this a faulted zone? Where is the fault? Between which strata? Is this a gradational contact? Where does one lithology end and the other begin? How would you describe the bed at the end of the carbonates and the beginning of the green phyllite?
It is up to you.
The descent is probably more difficult than the climb but it is much faster. Be careful.

B7: ROBERTS HILL AND ALBRIGHTS REEFS: FAUNAL AND SEDIMENTARY EVIDENCE FOR AN EASTERN ONONDAGA SEA-LEVEL FLUCTUATION
Thomas H. Wolosz
Center for Earth and Environmental Sciences
SUNY College at Plattsburgh
Plattsburgh, N.v. T2901

B7: ROBERTS HILL AND ALBRIGHTS REEFS: FAUNAL AND SEDIMENTARY EVIDENCE FOR AN EASTERN ONONDAGA SEA-LEVEL FLUCTUATION

STOP 1. Albrights Reef
Park cars along shoulder of road. Main part of reef lies to the right (east). Exposures along road are crinoidal sand/favositid flank deposits. Cliff face about 130 feet to east exposes rugosan constructed Inner Core.

STOP 2. Roberts Hill Reef.
Reef lies to the east of the road and makes up the entire northern portion of the hill. Old logging road marks approximate southern end of reef. Exposures to the west of the road and south of the logging road consist of post-reef growth flanks.
CAUTION: SOLUTION EXPANDED JOINTS ARE COMMON ON THE TOP OF THE HILL AND ARE COMMONLY FILLED WITH LEAVES. PLEASE WATCH YOUR STEP.

B8: DEGLACIATION OF THE MIDDLE MOHAWK AND SACANDAGA VALLEYS, OR A TALE OF TWO TONGUES*
Robert J. Dineen
The State Education Department
Albany, NY 12230
Eric L. Hanson
Dunn Geoscience Corporation
5 Northway Lane
North Latham, NY 12110
The middle Mohawk Valley contains a record of the interaction between the Mohawk and Sacandaga glacial lobes, including evidence for several readvances. We will examine exposures in deposits that document these interactions and features.

B8: DEGLACIATION OF THE MIDDLE MOHAWK AND SACANDAGA VALLEYS, OR A TALE OF TWO TONGUES

You are on the Quaker Springs delta.

Kame moraine.

Follow North Street to the right (northeast), along south edge of Interlobate Moraine.

STOP 1: Broadalbin Town Landfill
This pit reveals the products of the ice-marginal environment. Here, the Yosts Readvance reached its maximum extent. The massive basal sands contain dewatering features (flame, dish, ball-and-pillow structures) .. These basal sands are sharply truncated, and overlain by fluvial sand with gravel that contains many reverse graded diamictons (flowtills).
Another pit, 0.4 m (0.7 km) west of Stop 1 shows evidence of more active ice. At this pit, a sequence of trough crossbedded sand is shared and overlain by a thick (1 to 3 m) diamicton.

Proceed along Lake Sacandaga sands to the intersection of NY Routes 29 and 30.

Perth Moraine and Perth Recessional Moraine
The upland that we drove over is the broad platform of the Perth Moraine. The low rise that we cross just before the stoplight is the Perth Recessional Moraine.

STOP 2. Perth Pit
We are on the Perth moraine, in a pit that cuts into the Perth Recessional Moraine. The base of the pit is trough-crossbedded outwash, overlain by 3 m of sand-matrix-supported diamicton. This till is overlain by trough-cross-laminated outwash sand and gravel. Wells nearby indicate that the pit is underlain by 30 to 40 m of interbedded till and sand. The till in this pit probably was deposited by the Yosts Readvance.

The Interlobate Moraine is on the right.
Follow the outlet of Lake Sacandaga to the long access road at the next Stop.

STOP 3. Rex Excavating
This exceptional pit has many instructive exposures. The base of the pit is bluish-gray clayey Mohawk till, overlain by 5 m of laminated fine sand, cut by trough-cross bedded sand and gravel. The sand and gravel is capped by 2 m of weathered till that is overlain by another sequence of lacustrine sand and prograding outwash. Till overlies this outwash, and is interbedded with lacustrine sand.
The multiple tills are the products of at least two readvances. The soil zone between the major sequences suggest several thousand years separated the two advances. Both sequences involved glacial ice overriding proglacial lacustrine and outwash deposits. The several tills above the soil zone probably were mudflows and lodgement tills of the Yosts Readvance. A similar exposure lies 1.1 miles to the east.

Cross the Cayadutta Spillway.

STOP 4. Twin Cities Sand and Gravel
This immense pit is over 300 m long and 7 m high.
It is the distal portion of the Interlobate Moraine, and contains distinct deltaic features. Both thrust and gravity faults are common, especially on the eastern end of the pit. A sandy diamicton caps the sandy deltaic sequence. Aeolian sand unconformably overlies the sandy till on the eastern end of the pit.

Drive up ice-contact slope and onto delta
Drive up ice-contact slope of the Interlobate Moraine and onto the Lake Gloversville delta.

Nice drumlins to the west, the Interlobate Moraine dominates the skyline to the southeast.

STOP 5. Mayfield Pits
This complex of pits is developed in an esker that drained the Sacandaga ice tongue. A subaqueous sand and gravel fan lies at the mouth of this esker. It was built by meltwater flowing in an ice tunnel into Lake Sacandaga. The esker is interbedded with lake sand.

58TH ANNUAL MEETING
Institute for the Study of the Continents
CORNELL UNIVERSITY
ITHACA, NEW YORK
Published by the New York State Geological Association.
Additional copies available from Manfred P. Wolff,
Executive Secretary, New York State Geological
Association, Geology Department, Hofstra University,
Hempstead, New York 11550.
PREFACE AND ACKNOWLEDGMENTS
It is a pleasure to welcome all of you to the 58th annual meeting of the New York State Geological Association and to Cornell University.
Ithaca and the Finger Lakes region offer much to satisfy a wide range of geological interests. Field trips have been arranged to show this diversity. Topics include general geology, geomechanics, geomorphology, glacial geology, kimberlites, paleobiology, paleoenvironments, petrology of continental basement and the mantle, sedimentary petrology, stratigraphy, structure, and tectonics. I hope the field guide proves as lastingly useful as the one from the 1959 meeting, when NYSGA last met at Cornell.
I want to thank the field trip leaders and other contributors for their efforts on behalf of NYSGA.
John L. Cisne, President
Department of Geological Sciences and
Ithaca, New York 14853

1: SUBMARINE EROSION ON THE DYSAEROBIC SEAFLOOR: MIDDLE DEVONIAN CORRASIONAL DISCONFORMITIES IN THE CAYUGA VALLEY REGION
GORDON C. BAIRD
SUNY College Fredonia
Fredonia , N.Y. 14063
CARLTON E. BRETT
Rochester, N.Y . 14627
Many Devonian black shale units in New York and adjoining states are marked by erosional unconformities along their bases. Of particular note are distinctive lag accumulations of detrital pyrite, phosphatic debris, and bones along these discontinuity surfaces. This debris is derived from the scour of underlying units and it is often concentrated in erosional runnel-like depressions which explains the typical occurrence of this material as laterally discontinuous lenses in outcrops.
This reworked material is remarkable in that pre-formed pyrite was reworked as pyrite gravel; several lines of evidence in support of this include: similarity of reworked grains to underlying in-situ pyrite, distinctive patterns of pyrite grain breakage within lenses, and the reorientation of geopetal stalactitic pyrite. The absence of detrital carbonate allochems within debris lenses and the facies-specific association of these lenses with black shale deposits, indicate : 1, that detrital pyrite was stable on the anoxic or minimally dysaerobic seafloor; 2 , that carbonate material (loose allochems on exposed limestone
Where carbonate dissolution accompanies mechanical abrasion of the seafloor we refer to the resultant erosion surface as a corrasional discontinuity; although this word has been used to describe several unrelated erosion processes, it has been introduced previously to describe submarine erosion by a combined process of abrasion and corrosion (see Gary et al. eds., Glossary of Geology, 1972).

Corrasional Unconformities

Tremain State Marine Park

Outcrops of Sherburne siltstone (Genesee Fm) on left.

Glenwood Creek
Falls over Fir Tree beds (lower Genesee Formation) just east of road.

Cross Willow Point Creek
Good exposure of Tully Limestone and Windom Shale.

Cross mouth of Taughannock Creek
To the left (upstream) from the road bridge a low waterfall is visible; this section includes the Tully Formation (limestone) overlying the uppermost Hamilton Group (Windom shale); we will examine the gorge section upstream from this site.

STOP 1. TAUGHANNOCK FALLS
Location: Taughannock Falls Park overlook on north side of Taughannock Creek about l km southwest of N. Y. Route 89 town of Ulysses, Tompkins Co., N.Y. (Ludlowville 7. 5' Quadrangle).
References: Cornell University Department of Geology (1959); deWitt and Colton (1978); Kirchgasser (1981, this volume) .
Description: This overlook provides a spectacular view of the 66 m (215') high Taughannock Falls (purportedly the highest falls east of the Mississippi), a hanging valley at the end of about a mile long post-glacial gorge (Fig. 12). The configuration of the falls is controlled by prominent joints; it is held up by resistant siltstone beds in the Sherburne Member.
In the early days of the silver screen, this locality and nearby glens were used as backdrops for early westerns, owing to the spectacular canyon-like walls in these gorges. Another interesting side light of this outcrop is the occurrence of thin (1-2 cm) dikes of Mesozoic kimberlite-like (actually alnoite) intrusive rock that crop out in the stream bed at the base of the falls (see Kay and Foster, this volume).
Gorge walls, up to 120 m (200-400') high, expose shales and siltstones of the lower Genesee Formation of late Givetian to early Frasnian (latest Middle to earliest Late Devonian) age. Depending upon the source, three or four members of the Genesee Formation are recognized at this locality. Black shales of the Geneseo Member form the lowest exposed unit; the plunge pool level is about 3.8 m above the base of this member, the gradational lower contact with the Tully Formation being exposed downstream. The upper contact is about halfway up the face of the falls, 27m (90') above the plunge pool and can be recognized by a change in coloration and bedding. The Geneseo is nearly barren, platy to fissile black shale; it is largely covered by talus at the base of the gorge walls.
The overlying 26 m (80') unit in the falls face is readily recognizable as a lighter grey-weathering interval with several prominent bands (of silty limestone) near the base and a major system of smooth, vertical joints within the middle and upper parts of this division. This interval has been termed Penn Yan shale (deWitt and Colton, 1978; Patchen and Dugolinski, 1979) or simply lower Sherburne siltstone (Kirchgasser, 1981). In actuality, neither term is entirely appropriate as these shales are correlative with upper Geneseo beds below the base of the Penn Yan or Sherburne elsewhere which has been placed at the Lodi Limestone bed. Recent study shows that the lower, 6-7 m (19-22') thick part of this unit, characterized by dark brown, rhythmically-bedded, silty limestone layers corresponds to a usually thin interval of auloporid coral-bearing carbonates termed the Fir Tree submember of the Geneseo Member (Baird and Brett, 1986). In this particular area, however, the Fir Tree Submember is very thick and the limestone beds are very sparsely fossiliferous and seemingly turbiditic; this unit is the expanded equivalent of much thinner, condensed, and auloporid-rich, limestone facies to the north (see Figs. 6, 7, 13: stops 2 and 3). Above the Fir Tree interval is approximately 22 m (70') of silty shale which is largely black in the lower portion but which becomes progressively more silty towards the top. This sequence (Hubbard Quarry shale submember of the Geneseo Member), like the Fir Tree below it, thins markedly to 4 m (13') at the type section, Hubbard Quarry (Stop 2) near Interlaken. Recently, conodonts of the disparalis zone (upper Givetian) have been obtained from the top of the Hubbard Quarry shale interval at the Lodi type section on Mill Creek (W .T. Kirchgasser pers. comm.). Ancyrodella rotundiloba, indicative of the lower asymmetricus zone, now accepted as the base of the Frasnian stage, has been observed from shales immediately overlying the Lodi horizon in westernmost Ontario County, N.Y. (Kirchgasser, pers. comm.). This indicates that the Middle/Upper Devonian boundary closely overlies the Lodi bed within the lowermost Penn Yan or Sherburne members. At Taughannock Falls the Middle/Upper Devonian boundary is probably at or near the lip of these falls.
Above the Hubbard Quarry submember is the 26 m (80') Sherburne siltstone member; the base of this unit can be seen as an abrupt change from the smooth joint-faced Hubbard Quarry interval to an irregularly-bedded and more resistant siltstone sequence about 9 m (30') below the falls lip. Although the lowermost Sherburne is obviously inaccessible at this locality, the basal 3 meters (10') of the member includes the silty, auloporid coral-rich interval of the Lodi unit, as can more easily be seen beneath the Route 89 overpass bridge at a small, nearby creek (Loc. GEN 4 of deWitt and Colton, 1978) 0.65 miles northwest of Taughannock Point. In this region, the Lodi is composed of bioturbated calcareous siltstone which yields auloporids, small bivalves, and the diagnostic goniatite Ponticeras perlatum.
In the upper cliffs (about 11 m (35') above the level of the falls lip) the Renwick Shale Member forms a distinctive marker. It consists of dark grey-weathering shales with thick, light grey, highly convoluted turbidite siltstones. The Renwick Member, about 10 m (32') thick at this location, is considered to be an important stratigraphic marker. It consists of interbedded silty, black shale which is distinctly interbedded with lenticular and often channeloid sandstone bodies which appear to be of turbiditic origin.
The highest beds, overlying the Renwick to the top of the gorge are flaggy, brownish grey-weathering siltstones of the Ithaca Formation.
Interpretation: The visible Genesee section (lower middle Geneseo-to-lower Ithaca) stratigraphic succession at this falls is equivalent to approximately 2 meters (6.5') of Geneseo-Penn Yan section at Cayuga Creek in eastern Erie County; the tremendous southeastward expansion of this sequence shows the influence of Catskill Delta progradation in this basin setting.
The Geneseo represents a major deepening event associated with the Taghanic onlap event. This transgressive event, occurring near the end of the Middle Devonian is recognizable nearly worldwide and is almost certainly eustatic in nature. In New York it is associated with major black shale deposition indicating anoxic bottom waters. The Fir Tree and Lodi intervals appear to record brief interruptions in the anoxia allowing colonization of the sea floor by a low diversity benthic fauna including auloporid corals and small brachiopods and mollusks, whereas the Hubbard Quarry, parts of the Sherburne and Renwick reflect a return to more dysaerobic, perhaps deeper, water conditions. Superimposed upon these fluctuations of the aerobic/anaerobic water masses was a general increase in the impact of silty turbidites, associated with progradation of the Catskill Delta.
At this locality the 6 to 7 meter (19-22') thick Fir Tree section and the overlying 20 to 22 meter (65-70') thick Hubbard Quarry shale interval are greatly expanded equivalents of far thinner deposits some 6 miles to the north (see text) and stops 2 and 3. The Fir Tree submember thickens exponentially southward from the latitude of Interlaken, King Ferry, and Genoa and undergoes a profound facies change from a compact, auloporid-rich, concretionary limestone bed in the north to a thick splayed succession of turbiditic concretionary "ribbon" limestone beds at Taughannock Falls (Figs. 5-7, 13). South of this locality, the Fir Tree interval continues to thicken, and this unit loses its identity into Sherburne facies before this interval dips below surface view, just north of Ithaca. The Lodi interval remains relatively thin through the Seneca, Cayuga, Salmon Creek, and Owasco Valleys, though it becomes coarser and, eventually, quite shell-rich east of the Owasco Valley .

Bridge over Trumansburg Creek
A large waterfalls east of the bridge exposes about 4 m (13') of interbedded limestone and shale at the Fir Tree position.

Pull-off on right overlook on Cayuga Lake
Note Lake Ridge Point and Milliken Power Station on east side of lake.

Little Point Road.
Little Point Creek shows about 2.4 m (7') of Fir Tree interval (slabby limestones with shale interbeds, 8 m (26') of Hubbard Quarry shale, and 3 m (10') of Lodi auloporid bearing calcareous siltstone.

Entrance to Rocky Dock Campsite on right.
Rocky Dock Creek near campsite ground shows high waterfalls capped by Sherburne siltstone. Fir Tree is 1.6 m (5.5' ) thick.

Outcrop of Sherburne siltstone in road ditch.

STOP 2. UNNAMED RAVINE NEAR BERGEN BEACH POINT
Location: Unnamed ravine south of Bergen Beach, 0.5 mi. west (upstream) of Bergen Beach Point, town of Covert, Seneca Co. (Trumansburg 7 . 5' Quadrangle).
Description: The waterfalls section on this small stream displays strata within the upper Geneseo Member and the lowermost Sherburne Member of the Genesee Formation. Lower rock divisions (Windom Shale Member and Tully Formation) exposed both downstream and along the adjacent lake shore will not be examined here. This section is a greatly thinned lateral equivalent of the section exposed in the Taughannock Falls face; approximately 70 meters (215') of that section below the Lodi bed has thinned to less than half of that thickness here with most of the northward thinning taking place in the Fir Tree and Hubbard Quarry intervals (compare figures 12 and 13 of road log).
In the gently sloped floor of this creek, hard black, fissile to platy, Geneseo black shale is exposed. The first prominent lip or ledge in the lower falls face , however, marks the position of the Fir Tree Limestone submember which is separated from the overlying, falls-capping basal Sherburne (Lodi) section by 8.5 meters (27') of the Hubbard Quarry Shale Submember. At this locality, the upper part of the Hubbard Quarry submember and silty, hard, auloporid-rich strata of the Lodi Bed are inaccessible; we will observe this part of the section at STOP 3.
The Fir Tree Submember is markedly different at this section as compared with Stop 1; at Taughannock Falls and adjacent creeks the Fir Tree exceeds 5 meters (16') in thickness and consists of an alternation of dark shale and brown, concretionary to distinctly turbiditic, silty limestone beds. These sparsely fossiliferous "ribbon" limestones converge exponentially northward to form a thin, massive auloporid coral-rich impure limestone bed in this region (Figs. 6, 13). The allodapic limestone facies of the Trumansburg-Lansing area is replaced northward by increasingly fossil-rich, and bioturbated facies which is essentially identical to that of the Lodi Bed in the Seneca Valley region. The Fir Tree biota, through conspicuously auloporid coral-rich, is not really very diverse; we believe that the 0.6 meter (1.7')-thick Fir Tree Bed at this locality records an episode of reduced sediment supply and turbidity in a dysaerobic or minimally aerobic bottom setting. This would explain the absence of stereolasmatid corals, large brachiopods, and bryozoans in condensed Fir Tree deposits.
One feature of the Fir Tree Submember, however, stands out; its upper contact with black, laminated, silty shale beds of the lower Hubbard Quarry shale interval is sharp and planar . This marks the position of a submarine discontinuity, which first appears about 2. 5 miles south of this locality. This break increases in magnitude northward along three separate, southeast-northwest transects in the Seneca, Cayuga and Salmon creek valleys, eventually overstepping the condensed Fir Tree deposit in each valley (see text, Stop 3: Figs. 5, 6, 13). This pattern of erosional overstep is strikingly similar to that observed at the Lodi level further to the northwest in the Seneca Lake Valley. This discontinuity, overlain by black Hubbard Quarry shale is distinctive for thin (0-0.8 cm-thick) accumulations of reworked pyrite, orbiculoid fragments, and occasional pieces of bone; this material can be skimmed up with a chisel from discontinuous debris lenses at the top of the Fir Tree Falls bench.
Above the Fir Tree Bench is a 2.5 meter (8')-thick sequence of lower Hubbard Quarry black shale facies which contains numerous Leiorhynchus guadricostrata? and Orbiculoidea lodiensis on many bedding planes; above this level, the Hubbard Quarry Submember displays an upward-coarsening and upward-shallowing facies succession to the base of the Lodi Bed. Upper Hubbard Quarry beds are distinctly silty and ledge; these strata are usually variably bioturbated and diminutive molluscan material as well as occasional auloporid corals can be found at some levels.
At the top of the lower Hubbard Quarry black shale sequence, 2.5 meters (8') above the Fir Tree bench, is another erosional discontinuity which is marked by reworked pyrite. This is associated with a current-rippled siltstone layer which we informally term the Bergen Beach bed; this unit can be traced into surrounding gullies, and it may mark the approximate position in this section of still a third Lodi-like unit which is developed within the Hubbard Quarry interval in the Seneca Lake Valley. Sectioned specimens of this siltstone bed at this locality show spectacular density-shape sorting of the pyrite grains into distinctive laterally segregated lentils on the scour surface beneath the quartz silt.

Unnamed creek
Here Fir Tree is 45 cm (1.5') thick and overlain by a pyrite layer up to 3 cm (1.5") thick.

North fork Interlaken Creek
Fir Tree bed is compact 6" ledge here.

Lively Run Creek.
Exposure of Lodi bed; Fir Tree level is inaccessible; prepare to stop.

STOP 3 HUBBARD SHALE QUARRY
Locality: Small shale pit on east side of N.Y. Rt. 89 and about 0.3 km north of bridge over Lively Run Creek, town of Covert Seneca County, N.Y. (Sheldrake 7.5' Quadrangle).
References: Cornell Univ., 1951; deWitt and Colton, 1978; Kirchgasser, 1981; Van Diver, 1980; Baird and Brett, 1986; Hubbard Quarry Shale type section.
Description: The floor of this shale pit exposes very dark grey to black, platy shale of the Geneseo Member (Genesee Formation). A layer of tabular, rusty stained carbonate concretions, containing auloporid corals is exposed near the lowest (northeast) end of the quarry. This is the northern feather edge of the Fir Tree limestone Submember which is represented at Taughannock Falls by about 5-6 m (16'-19') of alternating tabular limestones and dark shale. Here the unit is condensed and has been almost completely truncated by submarine erosion (Fig. 13). Note the discontinuous sheet accumulation of reworked pyrite debris and orbiculoid fragments that marks the position of the discontinuity that cuts out the Fir Tree deposit. This same discontinuity can be followed locally within the undifferentiated Geneseo black shale succession north past the Fir Tree bevelled margin; reworked pyrite and bone debris occurs locally, concentrated at the discontinuity position, usually as a lag concentration at the base of a bed of rippled, winnowed siltstone. Similar, nearly bevelled, Fir Tree deposits can be seen across Cayuga Lake southwest of King Ferry and in the Salmon Creek Valley just south of Genoa. This margin cannot be seen in the Seneca Lake Valley because it is below lake level north of the Fir Tree anticline, but we suspect that its position should be just south of Baskin and Caywood points on that lake.
The overlying black, fissile shale, here about 4.3 m (14') thick, has been designated the Hubbard Quarry submember (Baird and Brett, in prep.) it contains bedding planes covered with the flattened specimens of Leiorhynchus guadricostatum and Orbiculoidea lodiensis. Two or three horizons of large septarian concretions, containing calcite and barite filled fractures, appear in the upper part of this division. The lower 2-2.5 meters (6.5-8.0') of the Hubbard Quarry Submember is a fissile to platy black shale. The upper part of this unit, below the Lodi beds, consists of grey to olive grey, silty mudstone which contains several thin siltstone beds; this interval, though poor in body fossils, is variably bioturbated suggesting deposition under dysaerobic conditions. The Bergen Beach bed of Stop 2 is not evident here.
The Hubbard Quarry shale is overlain by a nodular calcareous siltstone with very abundant auloporid corals, which is the local representation of the Lodi Submember, marking the base of the Sherburne-Penn Yan Member (Fig. 13). As noted at Taughannock, this bed lies slightly below the Givetian/Frasnian (Middle/Upper Devonian) boundary. The Lodi grades northwestward into a more prominent and more fossil-rich concretionary silty limestone bed in the vicinity of Lodi and Ovid (see STOP 4: Fig. 13) before it, too, is bevelled below a black shale tongue still farther to the northwest.

Kidders Gully north fork.
Remnant pods of Fir Tree beds found here. Hubbard Quarry Shale is 4 m (13 ft.) thick.

South fork Sheldrake Creek
In large water falls east of Rt. 96, Fir Tree bed is absent, Lodi caps falls.

Unnamed creek with good Hamilton exposures.

Groves Creek.
Tully/Windom exposure is below road, in small quarry-water falls area.

Barnum Creek
Shale pit in Windom Shale Member on left.

STOP 4 OVID SHALE QUARRY
Location: Shale pit 1.2 miles northwest of Ovid, Seneca County. North-south entrance road to pit is on the south side of West Blaine road 0.75 mile west of the Rt. 96-414/west Blaine road intersection in the town of Ovid. Ovid 7.5' Quadrangle.
References: This is locality OV-16: deWitt and Colton (1978) .
Description: This borrow pit is excavated mainly into hard, fissile to platy, black shale facies of the Geneseo Member; the uppermost 10 meters (30') of this unit is visible here as is the basal contact with the overlying Penn Yan Shale Member (Fig. 13). This contact corresponds to the base of the 0.4-0.6 meter (1.2-1.8')-thick Lodi limestone bed which is exposed at the top of the south and east walls of the pit. The Lodi bed is easily seen in loose blocks around the quarry; it is composed of nodular concretionary grey limestone masses with associated calcareous, silty, gray mudstone. This unit contains framestone thickets of auloporid corals which probably partly control the form and distribution of concretions within the bed. The Lodi fauna in this region is richer than at Stop 3; the auloporid growth is more profuse here and additional taxa, including the brachiopod Pseudoatrypa devoniana, the gastropod Palaeozygopleura as well as numerous small bivalves and pelmatozoan debris, can be collected here. The Lodi here is overlain by rusty-weathering, silty, black shale facies comprising higher Penn Yan beds.
Discussion: This section displays an uncanny resemblance to those at stops 2 and 3; at those places an auloporid rich unit was developed within a black shale sequence much like what we see at this stop. The deception here is that the auloporid-rich beds at these stops seem to be all one and the same. In reality, we are looking at a repetition of the Fir Tree facies motif at the horizon of the Lodi; at this locality no Fir Tree beds are present and the Lodi has changed northwestward from a nondescript, rubbly siltstone deposit at Stop 3 to a more impressive fossil-rich ledge resembling the Fir Tree layer near its northern bevelled margin (Fig. 13).
This similarity becomes even more impressive due to the fact that the Lodi bed at this stop is close to its northwestward erosional margin; the Lodi is completely absent directly across Seneca Lake in localities near Dresden. An imaginary projection of the strike of the Lodi erosional margin (Fig. 8), based on its northeast-southwest alignment near Himrod west of Seneca Lake, would place the Lodi erosional limit less than a mile northwest of this pit.
As with the post-Fir Tree discontinuity, the erosion surface above the Lodi is marked by a discontinuous lag layer of reworked material which underlies black to dark gray, transgressive facies. At this locality a one to three centimeter (0.5" -1.5")-thick layer of transported auloporid coral debris, pelmatozoan fragments, and subordinate detrital pyrite marks this contact at the top of the Lodi. In the vicinity of Himrod, this surface is marked by a discontinuous lag accumulation of reworked pyrite with little or no associated carbonate allochems.
Three meters (10') below the Lodi Bed in this section is a band of septarial concretions near the top of a meter-thick interval of dark gray chippy shale which is not as black as Geneseo beds above and below. We believe that the sharp upper contact of this interval with laminated black shale facies corresponds to the post-Fir Tree discontinuity within the Geneseo Member proper (Fig. 13). This contact shows that what may, at first, appear to be a homogenous and continuous black shale sequence may, in actuality, be a stacked, discontinuous succession of black shale packages bracketed by numerous internal erosion surfaces.

POPLAR BEACH SHALE PIT. (OPTIONAL STOP)
Location: Shale borrow pit bordering the east side of Iron Bridge Road 0.7 mile southwest of Poplar Beach, Town of Romulus, Seneca County; pit also borders north branch of an unnamed creek which flows into Poplar Beach. Ovid 7.5' Quadrangle.
References: Baird, 1981.
Description: This shale pit is developed in medium to dark gray, chippy mudstone facies of the Wanakah (=King Ferry) Shale Member (Ludlowville Formation: Hamilton Group). This shale interval is sparsely fossiliferous and nearly homogeneous, with the sole exception of a layer of reworked calcareous hiatus-concretions which can be easily sampled on the service road leading into the pit and from the upper parts of the shale banks within the pit.
Discussion: This stop is included to show the great difference between submarine discontinuities developed under anaerobic or minimally dysaerobic conditions and those produced in aerobic settings. This discontinuity is one of two very similar horizons which were mapped within the King Ferry Member as part of a study of mechanical and bioerosional processes on a regionally sloped, mud-floored, Devonian sea floor (for details see Baird, 1981; Baird and Brett, 1981: N.Y.S.G.A. Binghamton Meeting: Discussion on road log). At this locality, we merely wish to emphasize that infaunal organisms play a disproportionately greater role in the erosion process on oxygenated substrates owing mainly to their burrowing and boring activity. It should be noted also that burrowing animals may erase sedimentary discontinuities in unconsolidated or minimally consolidated muds; this commingling or thorough mixing of the older and younger sediments changes the discontinuity from a discrete contact into a stratomictic interval of scrambled mud, shells prefossilized debris, and reworked concretions or small nodules.
At this locality, the level of hiatus-concretions and associated shell hash (Barnum Creek Bed) marks the position of a stratomictic erosional discontinuity; there is no obvious erosion surface associated with these nodules-rather the hiatus-concretions almost "float" in a slush of burrowed shell debris and mud. This is a good collecting stop for the bored and bioencrusted hiatus-concretions. Epizoans on the nodules include auloporid corals, the rugose coral Stereolasma, ctenostome bryozoans , and occasional pelmatozoan holdfasts. Distinctive flask-shaped borings are abundant on some nodules. Scratch marks on nodule exteriors, produced by burrowers colliding with still-buried concretions, are commonly found at this locality.

Peter Witmer historic farm.

Fayette town shale pit
A turn to left leads to Fayette town shale pit, a well known Centerfield/Levanna section 0.3 miles west of this junction

Note stone farm house on left.

Entrance to Warren Brothers, Seneca Stone Quarry
Turn left into yard by office to obtain clearance to enter.

STOP 5. SENECA STONE QUARRY
Locality: Large quarry of Warren Brothers Co., 4 km SSE of Seneca Falls, just north of Yellow Tavern Road 1.5 km west of Canoga Springs, Seneca Co., N.Y. (Romulus 7.5' Quad.).
References: Oliver (1983); Rickard (1984); Conkin & Conkin (1984).
Description of Units: This active quarry displays an outstandingly complete sequence from the base of the Oriskany sandstone, through the complete Onondaga Formation and to the base of the overlying Marcellus Formation of the Hamilton Group. Oriskany Sandstone and its unconformable contacts can be observed in the floor of the quarry; four members of the Onondaga, including ash layers are variably well exposed in the east wall of the quarry along an access road ramp. The lower Hamilton sequence including (in 1986) an excellent dip slope exposure of the top of the Cherry Valley Limestone, is well exposed on the south rim of the quarry. Considerable structure is visible in the walls of the quarry including minor gentle folding and a north-directed thrust fault which places Seneca Member over Marcellus black shales on the southeast side of the quarry. Our attention here is directed to the uppermost beds in the quarry, though many features within lower quarry units are worth the effort of a return trip.
Uppermost Onondaga and Marcellus Stratigraphic Units
Onondaga Group: Seneca Limestone Member
The highest division of the Onondaga Limestone includes 8.5 m (26') of dark gray to nearly black, micritic limestone which is separated from the underlying Moorehouse Member by a distinctive, 20 cm (8")-thick, cream-colored soft clay layer which is the expression of the middle Tioga ash bed which is termed the Tioga B layer (Rickard, 1984) or the Onondaga Indian Nation Metabentonite using terminology of Conkin and Conkin, 1984. The Seneca Member is a moderately fossiliferous wackestone with some chert nodules, chonetid brachiopods, dalmanitid trilobites, and gastropods in its lower part, but it is distinctly, darker, more argillaceous, and sparser in macrofossils towards the top; in the uppermost beds only a meager dysaerobic biota of Styliolina shells, diminutive chonetids, and the burrows Planolites and Chondrites is observed. The Seneca Member appears to grade upward almost continuously into the overlying Union Springs Member of the Marcellus Formation. The overall Moorehouse to Union Springs stratigraphic succession records a major transgression in this region; Moorehouse and lowermost Seneca aerobic facies is succeeded by higher dysaerobic Seneca beds which, in turn, pass upward into minimally dysaerobic to anaerobic Union Springs deposits (Figs. 3, 14). This transgression was probably eustatic in nature (see Johnson et al., 1985) and timed with the introduction of a considerable amount of siliciclastic mud (although much of the Union Springs is still carbonate rich and technically a very argillaceous, black limestone). In most areas of New York both east and west of the Cayuga Lake meridian, the Onondaga-Marcellus contact is unconformable and probably erosional, but here, near the presumed basin center it appears conformable. The overlying Union Springs muds reflect major uplift of Acadian source terranes, and the tectonism may have been propagated westward to form minor diastrophic uplift of the Onondaga, prior to subsidence.
About 62 cm (2') below the top of the Seneca facies succession is a second, yellow-weathering ash layer which is designated as the Tioga A bed (Rickard, 1984) or Tioga "sensu stricto" (Conkin and Conkin, 1984); on fresh, back-piled slab heaps along the quarry rim, one can often find crumbly, micaceous pieces of this ash mixed in with the other darker rock fragments. Both the Tioga A and B ash beds produce distinctive rust-staining on the quarry walls due to weathering and their levels can be seen easily from the quarry rim.
Hamilton Group
Marcellus Formation
Union Springs Shale Member
The Seneca Member is overlain by about 4.3 meters (13') of sooty, black, fissile shale which contains numerous brown-black, concretionary limestone beds, as well as thin Styliolina packstone layers near the top and base of the unit (Fig. 14). The biota of this unit is of very low diversity; the l mm-long conical shells of Styliolina form the main component of tractional hash layers, and several other taxa including the brachiopods Ambocoelia and Leiorhynchus, the bivalve Pterochaenia, and cephalopods, occur only sparingly in this interval. The Union Springs is distinctly sooty and fractures, along within the numerous joint and fracture surfaces within limestone beds, are filled with pyrobitumen. Thin bone-rich beds occur within a 15-20 cm (6"-8")-thick interval of Styliolina packstone layers just above the base of the Union Springs. This layer, designated "Bone bed no. 7" by Conkin and Conkin (1984) is a widespread key marker in the Union Springs Member; we have traced this unit from the Jamesville Quarry near Syracuse to the General Crushed Stone ("Five Points") quarry northwest of Lima, Livingston County (Fig. 3). Locally, this bed displays spectacular concentrations of onychodid teeth, placoderm armor, and spines, as can be seen at the Jamesville quarry near Nedrow. Bone beds such as this mark diastems and possibly even larger discontinuities within the black shale; this pattern is very similar to the stye of submarine erosion which we observed in the Genesee Formation. Back-piled slabs of this bone-rich layer can be observed at this stop. The seemingly gradational nature of the Seneca-Union Springs contact in this region presents some difficulties in defining the top-Onondaga contact; Rickard (1984), places the Seneca-Union Springs boundary at the base of the upper ash bed, while Conkin and Conkin (1984), place it at a bone bed slightly below the ash. Neither of these layers truly coincide with the level where sooty Union Springs shale first predominates, further adding to the complexity of this problem.
Proetid Limestone Bed and Cherry Valley Limestone Member
Above the Union Springs is a distinctive, highly condensed limestone unit which can be traced in outcrop from the vicinity of Lima, Livingston County all the way into the Hudson Valley. At this locality this unit is a compact, 65 cm (2.2')-thick ledge which is actually composed of three amalgamated limestone subdivisions, two of which ("Proetid bed" and Cherry Valley Member, proper) are extraordinarily widespread. The basal few centimeters of the amalgamated ledge consists of a concretionary underbed which is actually a part of the Union Springs Member. This layer consists of large, brown, septarial concretions, which can be seen on large overturned blocks. Debris from the overlying "Proetid Bed" fills numerous cracks and solution pits which locally penetrate through the underbed.
"Proetid Limestone Bed": The next amalgamated division within the limestone ledge is a highly irregular, 5-15 cm (2-7")-thick white-weathering, light grey, micritic unit which is sandwiched between the brown concretionary layer and the true Cherry Valley Limestone (Fig. 14). This white horizon contains scattered fossils , particularly, a few atrypid and rhynchonellid brachiopods, comminuted crinoid debris and calyces of the minute crinoid Haplocrinites clio, rare small rugose corals and proetid trilobites . Overall, this bed closely resembles a layer, informally termed the "Proetid bed" (Rickard, 1952). In the east the proetid bed is separated from the overlying Cherry Valley Limestone by 0.1 to 3 m of black shale and thus it represents a distinct carbonate unit. It appears to merge with the base of the Cherry Valley Limestone near the Chenango Valley due to pinch out and/or erosion of the intervening shale. At Seneca Quarry the top of the proetid bed is an irregularly sculptured hardground with a relief or nearly 10 cm. Darker grey matrix of Cherry Valley lithology infills pockets including undercut cavities on this limestone, indicating a period of induration and erosion of the surface prior to Cherry Valley deposition.
Cherry Valley Member: The upper two thirds of the carbonate ledge comprises the true Cherry Valley limestone, it is a dark grey, slightly pyritic, styliolinid and crinoidal packstone with abundant orthoconic nautiloids and large goniatites (Agoniatites). These cephalopod are particularly well displayed on the upper surface of the bed. Along the southwest rim of the quarry this upper surface has been glacially polished and striated; however on the southern edge it was covered by a thin veneer of overlying Oatka Creek shale. This shale has been bulldozed off on a large, gently-dipping surface on the south edge of the quarry, exposing the unweathered upper contact of the Cherry Valley bed. This surface is nearly planar and displays a large number of erosionally truncated nautiloids, goniatites and a few large fish bones. In some cases the bevelled edges of the phragmocones and the chambers on this submarine hardground are encrusted with drusy crystalline pyrite.
This appears to represent a regionally traceable cephalopod bed. Nautiloids are well preserved and show a prominent and highly significant northwest to southeast orientation. This seems to indicate that the cephalopods died shortly before original burial and were oriented by basinward-flowing currents on the sea floor. Very few specimens are vertically oriented.
Bevelling of the fossils almost certainly took place on the Devonian sea floor after induration of the limestone. Examination of nearby sections indicates that a few centimeters of overlying Cherry Valley Limestone were removed from this surface exposing the prefossilized cephalopods. Erosional mechanisms probably included mechanical scour by traction sheets of residual debris and shells moved by currents (abrasion) and some component of submarine dissolution under anaerobic conditions prior to burial of this surface by Oatka Creek black muds (Baird and Brett, in prep.); evidence of this corrasion process becomes even more pronounced on this surface, further west at Flint Creek near Phelps, Ontario County and at LeRoy, Genesee County, where the discontinuity surface becomes distinctly irregular and pitted (see Fig. 3).
As noted for other submarine erosion surfaces (see discussion of Moonshine Falls), this erosive bevelling apparently accompanied sediment starvation associated with rapid transgression. The Cherry Valley is sharply overlain by black shale of the Oatka Creek-Chittenango members which records anaerobic conditions following Cherry Valley deposition.

Defunct Eisenhower College on left.

Road follows a conspicuous narrow ridge.

Bridge over Cayuga Lake outlet.
Entrance to Montezuma Wildlife Refuge

Camillus Shale
Slumped old roadcut in Camillus Shale (Upper Silurian).

Woods Quarry
Woods Quarry, behind large garage building on left; has exposures of the Onondaga-Marcellus (Union Springs) contact; the same upper Tioga ash layer and fish bone bed seen in Seneca Quarry are present here.

Bridge over Great Gully
Exposure of Mottville Limestone (Marcellus/Skaneateles contact) visible in low falls east of road.

Bridge over Criss Creek
More Mottville exposure (visible from road during cold months)

Bluffs of Levanna along Cayuga Lake shore.

Wells College on left.

STOP 6. PAINES CREEK; MOONSHINE FALLS
Locality: Exposures on the bed of Paines Creek above Moonshine Falls 0.3 km west of Moonshine Road, south of Aurora, Cayuga Co., NY.
References: Cooper (1930), Grasso (1970); Kramers (1979); Gray (1984).
Description of Units: Paines Creek flows north westward on the dip slope between the bridge at Moonshine Road and the 12 meter (40')-high waterfalls, exposing extensive bedding planes of the upper Centerfield and the basal Ledyard shale. Strongly jointed, dark, fissile Ledyard shale crops out beneath the bridge and for 100 m above the waterfall. This contact and most of the Centerfield Member are re-exposed still further 400 m upstream from the bridge at the crest of a small anticline. The face of the waterfalls (largely inaccessible) exposes the upper 2 meters (6.5') of the black Butternut-equivalent part of the Levanna Shale Member, a disconformity at the top of the Levanna, and 10.7 m (35') of the lower Centerfield. This sequence can be examined by descending into the gorge along a small tributary gully north of the crest of Moonshine Falls.
Centerfield Member : A fossil hash bed containing scattered hiatus concretions, encrusted by bryozoans and auloporid corals, forms the base of the Centerfield and rests sharply on black, fissile Leiorhynchus-bearing shales of the Levanna. Overlying Centerfield gray shales contain small brachiopods (Ambocoelia, chonetids) and, at two levels, biostromes of auloporid corals. Higher beds show a transition to gray, calcareous mudstone with larger brachiopods, particularly Tropidoleptus, and a few larger rugose corals.
The highest beds of the Centerfield, exposed in the creek floor above the lip of the waterfalls, are hard, light blue-grey, argillaceous limestones or very calcareous mudstones which are thoroughly bioturbated and display well-preserved large Zoophycos spreiten, typically with limonitic (originally pyritic) marginal tubes. Body fossils are abundant and very diverse but patchy in distribution. On the strongly jointed creek bed just above the waterfall are excellently exposed patches (biostromes) of ramose and foliose (fistuliporoid) bryozoans, some of which have associated brachiopods (rhynchonellids, Nucleospira, Elita, Vitulina as well as proetid and Phacops trilobites. Excellently preserved blastoids and crinoids are common in some bryozoan thickets at this level. Scattered large corals including solitary forms such as (Heliophyllum) and colonial taxa (Eridophyllum and Favosites) are also present.
Many localities show some 3 to 4 m of highly fossiliferous softer gray shales overlying the calcareous mudstone capping unit of Moonshine Falls which mark a transgressive facies transition into post-Centerfield deposits; however at this one locality these transitional beds are absent, apparently because of localized erosional truncation (Fig. 4). The upper contact of ·the Centerfield is disconformable here, as at adjacent localities, but the contact is very striking here owing to the lack of the sharply overlying black Ledyard shales. At the contact is a thin (1-2 cm) lag of crinoid debris with abundant fossils, derived from the underlying Centerfield; many of these are distinctly broken and corroded. This bed also contains abundant small phosphatic nodules, some of which are reworked fossil steinkerns (e.g. of conulariids and enrolled trilobites), fish bones and hiatus-concretions. Reworked, pyritized burrow tubes have been exhumed locally on this surface at some localities. However, where this has been observed, the tubes occur stratomictically commingled with shell hash in burrowed mudstone; these tubes, thus, show evidence of breakage and reorientation by infauna but no evidence of lateral current transport.
This lag bed, termed the Moonshine Falls Bed by Gray (1984) is an important widespread marker, which has yielded the conodont Polygnathus timorensis, diagnostic of the lower P. varcus zone of the Givetian stage; it is on the basis of these conodonts from this locality that Klapper (1981) has assigned the Centerfield to the base of the varcus zone; in actuality, no diagnostic conodonts have been obtained from the Centerfield proper, or from the underlying Skaneateles Formation.
Ledyard Shale: The basal 4 m of the Ledyard Member are exposed here, and this creek is the type section of that member. The lower beds are very dark gray to black, fissile shales with a Leiorhynchus-Styliolina fauna. A few thin stringers of crinoidal and phosphatic debris have been observed in the basal 10 cm of the Ledyard, these apparently have been reworked from lag debris overlying the erosional top of the Centerfield.
Interpretation: The Levanna-to-Centerfield sequence represents an abrupt change from deeper water black Leiorhynchus facies to fossil-rich calcareous mudrock, probably deposited in shallow water close to normal wave base, and within storm wave base. Although the sequence is gradational east of Syracuse meridian, here it is broken by a discontinuity that marks the sharp base of the Centerfield, Gray (1984) has interpreted this interruption in sedimentation to be the result of local tectonic uplift of the sea floor near the Tully Valley. This updoming could have cut off sediment influx to the west, leading to slight erosion of the sea floor and condensation of shelly debris. Above this basal bed the Centerfield shows a gradual shallowing-upward sequence to the beds that cap Moonshine Falls; above this hard mudstone, in other localities there is a reversal and gradual transition back to deeper water facies (Fig. 4). However, again, the sequence was interrupted in this area by an abrupt jump to dark gray and black Leiorhynchus facies. As noted above, the upper Centerfield transitional shales have been removed, apparently by erosion associated with this interruption in sedimentation. Detailed mapping of the upper contact (Gray, 1984) proved that the transitional shales are present within 2 miles on either side of Moonshine Falls (i.e. both northeast and southwest of here). This further suggests that the erosion was localized (Fig. 4); the area of enhanced erosion may be in a channel-like depression no more than a mile across and perhaps oriented NW-SE, normal to the regional paleoslope. This erosion probably took place during an interval of general sediment starvation associated with rapid transgression at the onset of Ledyard deposition. We have observed similar erosional furrowing beneath black shales at several other stratigraphic levels. That relatively strong currents persisted, episodically, even after the onset of black mud deposition, is indicated by the stringers of reworked Centerfield debris that occur just above the base of the black shale. Evidently, some dysaerobic settings were not entirely characterized by low energy.

Cross Lake Ridge Point Ravine
Here the Fir Tree Limestone is about 7' thick.

Cross Salmon Creek
Excellent upper Hamilton exposures are present in this creek.

Upper end of Shurger Glen.

Exposures of upper Sherburne turbiditic siltstone
Exposures of upper Sherburne turbiditic siltstone in intermittent road cuts on left; long grade is nearly on dip slope of south limb of Fir Tree anticline; large lake bank section of upper Geneseo, Fir Tree equivalent siltstones, and Hubbard Quarry turbidites and shales is below west of road.

Renwick, Ithaca members of Genesee Fm
Large cuts on 13 are into lower medial divisions (Renwick-Ithaca mbrs.) of the upper Genesee Formation.

2: SEDIMENTARY CYCLES AND LATERAL FACIES GRADIENTS ACROSS A MIDDLE DEVONIAN SHELF-TO-BASIN RAMP LUDLOWVILLE FORMATION, CAYUGA BASIN
CARLTON E. BRETT
Rochester , N.Y. 14627
GORDON C . BAIRD
SUNY College at Fredonia
Fredonia, N.Y. 14603
KEITH B. MILLER
Rochester, N.Y. 14627
The Middle Devonian (Givetian) Hamilton Group of western and central New York State constitutes an eastwardly-thickening wedge of black and grey shales, mudstones and siltstones with thin, but widespread, carbonate and sandstone units. These sediments were deposited in the northern end of the stratified Appalachian Basin following early phases of the Acadian Orogeny (Ettensohn, 1985; Kent, 1985). Hamilton facies occur in distinct cyclic motifs of two sorts: subsymmetrical cycles centered on maximally-regressive, limestone facies in western New York, and upward-coarsening, dark shale-siltstone-sandstone hemicycles capped by maximally regressive storm-winnowed deposits in the eastern Finger Lakes region. Recent detailed study of Hamilton stratigraphy and facies distribution has demonstrated that the two types of cycles are correlative
~
regressive-transgressive cycles and both carbonates and sandstones record relatively shallow water near wave base facies. This work further permits the development of models explaining the distribution of recurrent fossils associations - or biofacies along environmental gradients.
The Cayuga Lake Valley presents a unique opportunity to examine facies relationships within the upper Hamilton Group. This 42 mile-long valley produces a major southward deflection in the Hamilton outcrop belt allowing examination of strata well south of the prevailing east-west outcrop trend limit. Moreover, the effect is enhanced by the exposure of upper Hamilton beds along the crest of the Fir Tree anticline near the southern end of the lake. This structure , in effect, provides a "window" into the facies of the Upper Ludlowville and Moscow Formations in the Southern Tier, some 30 miles south of the main outcrop belt. Still more important is the fact that the present day Cayuga Valley appears to obliquely cross cut northeast/southwest-trending facies belts in the upper

2: SEDIMENTARY CYCLES AND LATERAL FACIES GRADIENTS ACROSS A MIDDLE DEVONIAN SHELF-TO-BASIN RAMP LUDLOWVILLE FORMATION, CAYUGA BASIN

Climbing long upgrade on Route 34
Note intermittent exposures of latest Middle Devonian Sherburne Siltstone (Genesee Formation); grade is nearly on dip slope of south limb of Fir Tree anticline.

Cross Salmon Creek
Cross Salmon Creek (original Ludlowville type section).

Cross Lake Point ravine.

Cross upper King Ferry Creek (which exposes Genesee Fm).

Feedlot on left shows exposures of Tully Limestone

Bluffs of Ludlowville shale
Narrow dirt road follows an old railroad bed along the lakeshore; it is bordered on the shore side by a row of cottages and on the other side by bluffs of Ludlowville shale (and outhouses!).

Small gully exposes lower Wanakah
Small gully exposes lower Wanakah (equivalent to type King Ferry Member of Cooper, 1930); from here onward there are intermittent joint face exposures of the lower Wanakah.

Small gully;
Lenses of concretionary, fossil-rich mudstone are visible in wall.

More fossil-rich lenses visible in weathered joint face.

STOP 1. KING FERRY STATION
Locality: Exposure along lake shore road extending from Elmwood Point, 1.6 miles south to near Cats Elbow Point, King Ferry Station, Cayuga Co., N.Y. (Sheldrake 7.5' Quadrangle).
References: Cooper (1930).
General Description: The south-dipping strata along the Cayuga Lake shore bluffs at King Ferry Station display the complete Wanakah Member (King Ferry Member of Cooper, 1930, in part), which is here somewhat over 30 meters thick (Fig. 8), over a lateral distance of about 1.6 miles. The Spafford and Owasco Members, comprising the uppermost 11 meters of the Ludlowville Formation are exposed at the southern end of this road near Cats Elbow Creek (Stop lC). The King Ferry locality is the most basinward, and thickest of the sections being examined on this field trip. A progressive northwest transition to an even thicker sequence of poorly fossiliferous, bioturbated, silty shales can be observed along the western margin of Cayuga Lake, as at Big Hollow Creek.
STOP 1A. ELMWOOD POINT
Upper Ledyard Member.--At section 1A we will examine the lower contact of the Wanakah shale at the base of a bed which we here designate the Elmwood Point bed for this locality. The uppermost two meters of the Ledyard Member can be seen below the Elmwood Point bed; the upper contact forms a prominent notch in the bank. These dark grey to nearly black shales contain common diminutive brachiopods (juvenile? Tropidoleptus, Truncalosia, Arnbocoelia), nuculid and Modiomorpha bivalves, orthoconic nautiloids, and Phacops trilobites concentrated on thin bedding plane horizons. This characteristic biofacies, occupying the identical stratigraphic position, can be traced to the west as far as Lake Erie without significant change. A harder, more calcareous bed, about 0.5 meters below the contact, contains a somewhat richer fauna, including the brachiopod Athyris, which is absent to the west, and gives the first hint of facies change which becomes increasingly apparent to the east and southeast, as at Cascade (Stop 2).
Wanakah ("King Ferry") Member.
The base of this member is marked by the very widespread, mollusk-dominated Elmwood Point Bed (equivalent to the Mt. Vernon bed or "Strophalosia" bed; Grabau, 1898-1899; Cooper, 1930), which, at this locality, remains nearly unchanged from its appearance in western New York except for the common occurrence of the brachiopod Mucospirifer and the absence of Truncalosia ("Strophalosia") . A major coarsening-upward cycle, about 18 meters thick, overlying this stratigraphic marker bed, begins with dark grey silty shales and culminates in massive, fretted, Zoophycos-burrowed siltstone. This cycle can be subdivided into three subtle subcycles. The lowest is only about 1.5 meters thick. It consists of dark grey, sparsely fossiliferous shale at the base, which grades upward into poorly fissile, burrowed, grey silty shales (Fig. 8) .
This sequence is overlain by about 3 m of slightly harder silty mudstone, with numerous thin siltstone layers, and a moderately diverse assemblage of brachiopods, including large Spinocyrtia, Cypricardella and Modiomorpha bivalves, trilobites, and the small discoidal tabulate coral Pleurodictyum. Fossils tend to occur in local lenticular (pod-like), somewhat concretionary-aggregates which are visible along a weathered joint face just south of a bridge over a small gully about, 0.1 miles south of the parking area. These pods are interpreted as primary skeletal accumulations which have been enhanced by early diagenesis. Several fossil bands and pods here appear to have been terminated by silty tempestites. The abundance of siltstones in this portion of the section suggests a shallow water position, above storm wave base. These beds are the equivalent of the Pleurodictyum "zone" that can be traced to Lake Erie (Grabau, 1898, 1899; Cooper, 1930).
At Romulus, on the northwest side of Cayuga Lake, this same interval expands to a 4.5 meter-thick, coarsening-upward subcycle of dark grey silty shale with a sparse fauna of nuculids and Cardiola bivalves, orthoconic cephalopods, and small brachiopods and capped by Pleurodictyum-bearing beds.

Cross King Ferry Creek
First outcrop south of the creek; shale here is about 6 m above the top of STOP 1A; a biostrome of rhomboporid and fenestellid bryozoans occurs here just above a thin siltstone, capping a second subcycle.

STOP 1B. KING FERRY STATION (SOUTH)
This bluff section displays the top of the lower Wanakah (Aurora submember) major cycle, which here forms a distinct bluff of massive siltstone; this unit shows a sharp upper platform because it is abruptly overlain by softer shale. The upper meter of the siltstone contains large spheroidal concretions associated with two lenticular, fossil-rich layers; the upper one, about 70 cm below the upper bench, contains the large rugose corals Heliophyllum and Cystiphylloides, together with a diverse assemblage of large bivalves, brachiopods, and bryozoans (Fig. 8). This appears to record maximal shallowing within the entire Wanakah. Winnowing and bypass of fine-grained-sediments produced a relatively clean, coarse-silt substrate which favored sporadic colonization by large corals.
An irregular, dense coquinite of brachiopods and Stereolasma corals immediately overlies the prominent siltstone bench and shows a hint of a minor coarsening upward cycle about 50 cm above that bench. This interval, here termed the Ensenore Ravine shell bed, is believed to correlate with Grabau's (1898-1899) lower trilobite bed (Murder Creek bed of Kloc, 1983) in western New York, with which it bears striking faunal similarity.
Three other major coarsening-upward cycles, each with minor subcycles, occur within the remaining 9.5 m of the Wanakah Member (Fig. 8). The lowest of these sequences will be examined by walking about 0.15 miles south of the parking area. Each subcycle has a well developed interval of irregular, commonly rust-stained concretions near its base and is capped by a thin, silty brachiopod-dominated coquinite. These coquinites display scoured bases with pods or gutter casts and nested stacks of convex-upward shells.
The lower shell cap bed can be correlated with the Barnum Creek bed, the upper thick coquinites with the Bloomer Creek bed, both of which become subtle, but widespread, shale-on-shale, hiatus concretion horizons to the northwest (Baird 1981 ; Baird and Brett, 1981).
The middle shell bed level is capped by a 2-4 cm thick cross laminated siltstone which is traceable to the west side of Cayuga Lake as the Mack Creek turbidite (Baird, 1981).

Cross Cats Elbow Creek
Creek exposes a section of the Wanakah with overlying units.

Yellow 10 mph signpost
Note excellent exposure of the Mack Creek turbidite siltstone.

STOP 1C. CATS ELBOW POINT (SOUTH)
This bank provides an excellent view of the top of the Wanakah Member, here a sharp contact at the top of a 30 cm-thick, shell-rich argillaceous limestone, the Bloomer Creek bed. This bed caps a second prominent shallowing cycle in the upper Wanakah Shale; mimicking the Ensenore Ravine bed seen at STOP lB; like the Ensenore bed the Bloomer bed contains a highly diverse brachiopod, bivalve, bryozoan assemblage with scattered large corals (Fig. 8). It correlates with a very shell-rich interval that is also traceable to Lake Erie (the Stictopora-Demissa zone of Grabau, 1898-1899; Blasdell beds of Kloc, 1983).
The Bloomer bed is sharply overlain by sparsely fossiliferous, dark grey shale of the lower Spafford Member. These shales coarsen upward into silty mudstone and siltstone, visible in the upper portion of this cliff section. Upper beds are 10 to 30 cm-thick, blocky, brownish-weathering, laminated siltstones with large concretions closely resembling the capping beds of the lower Wanakah (Aurora) cycle. This interval appears to be the northwestern equivalent of Smith's (1935) Owasco Member. It is separated from the Tichenor limestone in Cats Elbow Creek by about 40 cm of bluish grey mudstone with a very diverse fauna resembling the Jaycox Member west of Cayuga Lake. This section is critical in establishing a link between the lower Jaycox Member and the Owasco Member .
SYNOPSIS OF STOPS lA -lC.
In summary, this sequence of outcrops reveals the beginnings of a change within the upper Ludloville Formation from uniform dark grey to black shale with thin shell beds to a series of asymmetrical, shallowing-upward, muddy siltstone cycles and subcycles. In ascending order these cycles and their capping shelly or silty beds are: A) upper Ledyard: Elmwood Point bed; B) lower Wanakah (Darien Center-Aurora submember): Ensenore Ravine bed (and including three subtle subcycles); C) lower-middle Wanakah: Barnum Creek bed; D) middle Wanakah: Mack Creek bed; E) upper Wanakah: Bloomer Creek bed; F) Spafford Member: Owasco Siltstone. Most of these cycles are traceable, at least in western and central New York State, and appear to record allocyclic fluctuations in relative sea level.

Overlook into Owasco Valley.

Fillmore Glen State Park on right.

Cross Owasco Inlet

Minor Otisco shale outcrop.

STOP 2A. CASCADE; ROUTE 38 ROADCUT
Locality: Long roadcut along west side of N.Y. Route 38, on the west side of Owasco Lake Valley, town of Cascade, Cayuga Co., N.Y. (Moravia 7.5' Quadrangle).
Reference: Baird (1979).
Description: This roadcut provides an excellent exposure of the entire upper Ludlowville section from the upper Otisco Member through the Tichenor Limestone (Fig. 9). Most striking at this location is the clearly developed repetitive sequence of coarsening-upward cycles, capped by very diverse brachiopod-bivalve coquinites. These easily accessible beds, with extensive bedding plane exposures, are ideal for collecting a nearly complete suite of Hamilton fossils. The hierarchical pattern of subcyclic units is also very well displayed, here as are the iron-stained, concretionary intervals occurring toward the bases of the major coarsening upward cycles.
STOP 2A ROUTE 38 ROADCUT, CASCADE (LOWER)
Otisco Member and Elmwood Point Bed
The upper Ledyard Member-equivalent, here designated as upper Otisco Member, has changed noticeably in both litho-and biofacies, from dark, small brachiopod and mollusk-dominated shales seen at King Ferry to medium grey brachiopod-rich, silty shales here. Abundant Mucrospirifer and Athyris are associated with the bivalves Cypricardella and Modiomorpha, together with the more typical upper Ledyard nuculid bivalve-diminutive Tropidoleptus fauna.
The Elmwood Point bed can be seen at the top of the exposure along a side road intersecting Route 38. It is represented by a silty coquinite layer, up to 10 cm thick, with an irregular base (Fig. 9), which contains a moderately diverse assemblage dominated by the brachiopods Mucrospirifer, Mediospirifer and Athyris with associated strophomenid brachiopods and pterioid bivalves. The striking change from its appearance at King Ferry may be due, in part, to the condensation of the lowest, thin subcycle present at King Ferry onto the Elmwood Point bed continuing the eastward thinning trend from northwestern Cayuga Lake (Big
Hollow Creek)

Ludlowville and Tichenor
Roadcut on west side of road is in upper Ludlowville and overlying Tichenor ("Portland Point") interval

STOP 2B. ROUTE 38 ROADCUT, CASCADE (UPPER)
Wanakah/Ivy Point Member
This interval is dominantly muddy siltstone and is, thus, intermediate between the typical Wanakah and Ivy Point Members. Above the Elmwood Point bed the major lower cycle has both coarsened and thinned markedly to the east, being only about 7.5 meters thick at Cascade compared to over 17 meters at King Ferry (compare Figs. 8 and 9). This illustrates well our observation that sediment packages thicken basinward due to the rapid dumping of finer grained sediments bypassed from more proximal, wave swept environments.
Subcyclicity within the major lower cycle is more pronounced here than at either King Ferry or Portland Point (STOPS 1, 3). The lowest subcycle comprises 4-meters of highly bioturbated and sparsely fossiliferous silty mudstone contains several irregular, poddy fossil layers with a large brachiopod-bivalve fauna (including: Mucrospirifer, Mediospirifer, Athyris, Spinocyrtia, Protoleptostrophia, Tropidoleptus, Modiomorpha , Cypricardella, and Actinopteria). These beds likely correlate with the rhomboporid-rich interval at King Ferry. Above this is a 2-meter thick subcycle which coarsens upward into massive, locally hummocky cross stratified, coarse siltstone, indicating shallowing into normal wave base. Two prominent coraliferous horizons are present within the coarse upper unit which contain Cystiphylloides, Heliophyllum, and large hemispherical colonies of Favosites hamiltoniae. Certain of the solitary rugose corals show evidence of corrosion and reworking. This is clearly equivalent to the coral-bearing cap of the lower cycle at King Ferry. A thin (<1 meter) subcycle follows which is capped by a thin dense coquinite with an extremely diverse fauna. This bed is believed to be equivalent with the Ensenore bed which forms a prominent cap to the major lower cycle to the west as far as Sheldrake Creek on the west shore of Cayuga Lake.
The cycles capped by the Barnum, Mack, and Bloomer Creek beds are all siltier and more prominent than at King Ferry. Unlike the major cycle below, their thicknesses show little change from King Ferry; and the upper two cycles are even somewhat thicker. Most subcycles continue to be recognizable, and the upper two concretionary intervals are well developed. Abundant pyritized burrow tubes occur below the Barnum bed in a position analogous to the concretionary interval at King Ferry. The most easily identified interval in this cut is the rust-stained concretionary horizon below the Bloomer Creek shell bed. Each of the capping shell beds contains a diverse fauna, dominated by Athyris or Mucrospirifer.
Spafford Member and Owasco Members
The upper part of the Route 38 roadcut, near the crest of the hill, exposes the upper members of the Ludlowville Formation, and its contact with the overlying Moscow Formation (Fig. 9). The Bloomer bed at the top of the Wanakah/Ivy Point Member is not sharply defined but is represented by a series of closely spaced, discontinuous fossil coquinites with a very rich and diverse fauna, characterized by Athyris, Spinocyrtia, Pseodoatrypa,and Strophodonta demissa; these beds are considered to mark the top of the Ivy Point Member. The overlying the Spafford Shale Member is somewhat thinner than at King Ferry and contains a more diverse fauna, particularly typified by chonetid brachiopods and Tropidoleptus. The overlying Owasco Member displays marked coarsening and thinning due to the erosional truncation of the upper siltstones and Jaycox-like fossiliferous shales. We interpret this as the result of south-eastward downward cutting of the Tichenor Limestone Member which comes to rest directly on the Spafford at Portland Point. The Owasco shows distinctly more proximal facies than at King Ferry with Allanella-rich, sandy layers and hummocky cross-stratification.
The highest unit exposed in this part of the roadcut is the "Portland Point" Member; the Tichenor Limestone-equivalent is a coarse, crinoidal, coral rich packstone or grainstone. This unit is now considered to form the base of the Moscow Formation (Baird, 1979).

Entrance to Portland Point Quarry
Entrance to Portland Point Quarry (in Tully Limestone) on left.

Pulloff on right is next to Minnegar Falls over Tully Limestone.

Pit in dark lower Windom Shale on left.

Cargill Salt Company mine on right
Small Ludlowville outcrop on left.

STOP 3A. PORTLAND POINT; NORTHERN RAILROAD CUT
Locality: Exposures on railroad cut along east-shore of Cayuga Lake between Cargill Salt Company and abandoned cement plant, 0.1 to 0.3 km north of Portland Point, town of Lansing, Tompkins Co., N.Y. (Ludlowville 7.5' Quadrangle).
Reference: Patchen and Dugolinski (1979).
Description: This weathered railroad cut exposes about 12 m (40') of the lower Ivy Point Member and the underlying upper Otisco Shale Member near the crest of the east-west trending Fir Tree Anticline (Fig. 10). These are the oldest units exposed at the axis of this fold. This section and that in the adjacent mouth of Shurger Glen afford a direct look at facies far south of the normal east-west outcrop belt some 10 to 15 miles to the north of this area. The southward Ludlowville facies change (distinct coarsening of beds with pervasive shoreward biofacies transitions) along the Cayuga Valley clearly mirrors the eastward facies changes from the Aurora-King Ferry area to the Skaneateles Valley, and we use the terminology that Smith (1935) proposed for the Ludlowville Formation in the Skaneateles Valley in describing the section at Portland Point.
Otisco Shale Member
About 5 m of the upper Otisco Member consists of medium grey, highly fossiliferous, soft silty shale. Shell beds, especially near the top, yield abundant brachiopods, particularly Athyris, Tropidoleptus, Spinocyrtia, small bryozoans, and the rugose coral Stereolasma.
Ivy Point Siltstone Member
The upper boundary of the Otisco shales with the Ivy Point can be located at the base of a distinctive 65-70 cm (2.1 ft.)-thick silty ledge that contains abundant large brachiopods and bivalves. This unit is the Elmwood Point bed noted at both previous stops. Here the bed contains large brachiopods, such as Spinocyrtia, and rugose corals; hence, in comparing the three sections, this bed displays a gradient of increasing diversity and a change from ambocoeliid to Athyris to Spinocyrtia biofacies. This bed apparently formed by sediment condensation along a paleoslope and thus it provides a natural transect of paleocommunities.
Above the Elmwood Point bed is an 8 meter-(26 ft.)-thick major coarsening-upward cycle which we term the lower siltstone tongue of the Ivy Point Member. It is clearly the interval equivalent of the lower Wanakah (or Aurora submember) cycle seen at Stops 1 and 2, but it is very distinctly coarser-grained. This sequence weathers with a distinctly recessed area near the base, where softer mudstone deposits overlie the Elmwood Point bed (Fig. 10). A remnant of the cap of the middle subcycle at King Ferry Station can still be recognized in several thin, Mucrospirifer-and Tropidoleptus-dominated shell beds associated with subconcretionary pods. Higher units include massive Zoophycos-churned silty mudstones; these, in turn, grade upward into laminated coarse siltstone, displaying evidence of local channeling.
The upper portion of the lower Ivy Point cycle consists of hummocky cross-stratified coarse siltstone and fine sandstone. Joint surfaces in the intensely bioturbated siltstone display a distinctive "fretwork"-type of differential weathering, controlled to some extent by textural and/or compositional differences between sediment within and surrounding Zoophycos spreiten. Several layers of shell coquinite, composed mainly of the brachiopods "Allanella" tullius, Camarotoechia and minor shell hash, are visible near the top (Fig. 10). Large (up to 0.5 m diameter) calcareous concretions occur within a prominent 1.0 m thick, massive, buff-weathering coarse siltstone bed. This coarse bed caps the major regressive cycle and it is correlative with the coral-bearing siltstone bed at the top of the lower Wanakah cycle at King Ferry and Cascade (STOPS 1, 2); however, no corals have been found here, probably because this facies represents too unstable an environment. A meter-thick uppermost subcycle overlying the concretionary bed displays abundant fossil debris (mainly Allanella, Tropidoleptus,and Mucrospirifer) and is probably equivalent to the Ensenore Ravine bed; this subcycle is also capped by a coarse, slightly concretionary siltstone. Finally, this unit is overlain by softer grey and sparsely fossiliferous shale which grades upward, over about two meters, into another siltstone, probably the Barnum bed-equivalent.
Above the railroad cut, along the access road to Portland Point, a higher, but somewhat similar coarsening-upward cycle marks the position of the upper siltstone tongue of the Ivy Point Member, of Smith's (1935) terminology. This upper bench is capped by about half a meter of extremely shell-rich mudstone with abundant brachiopods, which is clearly correlative with the Bloomer Creek shell bed.

STOP 3B. GULF CREEK (SHURGER GLEN)
Locality: Exposures along the gorge of Gulf Creek 0.1 km east of its mouth at Portland Point, Tompkins Co., N.Y. (Ludlowville 7.5' Quadrangle).
References: Cooper (1930); Baird and Brett (1981); Patchen and Dugolinski
(1979).
Description of Units: The uppermost 11 meters (36') of the Ludlowville formation are exposed below a falls capped by Tichenor Limestone; these silty shales display a peculiar curved jointing pattern in the falls face (Fig. 10).
The top of the Ivy Point (or King Ferry) exposed near stream level, displays to advantage the Bloomer Creek shell bed which consists of two to three closely-spaced coquinite layers. Fossils at this level include the abundant brachiopods (e.g. Athyris, Pseudoatrypa, Spinocyrtia, Strophodonta demissa), bivalves (e.g. Cornellites, Cypricardella, and Modiomorpha), several bryozoans, and echinoderms, including the grapnel-like holdfast Ancyrocrinus and rare edrioasteroids. About 9 meters (29') of overlying, less fossiliferous, silty mudstone with occasional layers of coquinite is equivalent to Smith's (1935) Spafford Shale Member. The highest Ludlowville member (Owasco Sandstone), if ever present here, was apparently removed by the major sub-Tichenor erosion surface.
At the cap of the falls is Cooper's (1930) "Portland Point" Limestone Member, a very thin (0.9 m), condensed interval, with a basal (Tichenor-equivalent), crinoidal packstone ledge, and a middle silty calcareous shale division, which is equivalent to the Deep Run and Menteth Members of the Moscow Formation (Baird, 1979). Overlying this unit is another shell-rich bed (Rhipidomella-Centronella or "R-C" bed of the Kashong Member). A complete Windom Shale section and falls over the Tully Limestone are observable upstream from the first waterfalls.
DISCUSSION (STOPS 3A AND 3B): The Lansing railroad cut and adjacent Gulf Creek section display pervasively silty Ludlowville deposits which have a strong similarity to the upper Ludlowville sequence in the Skaneateles Valley near Spafford; Smith's (1935) Ivy Point and Spafford successions of the Skaneateles Valley are clearly discernable here. This similarity holds both for lithofacies and biofacies. It should also be remembered that most regional facies changes, and resulting difficulties of correlation, within the Ludlowville interval are encountered within 35 km (20 mi) along the northwest-southeast trending Cayuga Valley. Sparsely fossiliferous grey shales in the lower Wanakah section at Romulus transform southeastward to sandstones at Portland Point, and black shales in the northwestern upper Wanakah sections change to shell-rich grey silty mudstone lithology in this area.

3: THE USE OF JOINT PATTERNS FOR UNDERSTANDING THE ALLEGHANIAN OROGENY IN THE UPPER DEVONIAN APPALACHIAN BASIN, FINGER LAKES DISTRICT, NEW YORK
TERRY ENGELDER
Department of Geosciences
Pennsylvania State University
University Park, Pennsylvania 16802
REGIONAL SIGNIFICANCE
Abundant evidence (deformed fossils) for layer parallel shortening in western New York indicates the extent to which the Alleghanian Orogeny affected the Appalachian Plateau (Engelder and Engelder, 1977). In addition low amplitude(< 100 m) long wave length(< 15 km) folds the Upper Devonian sediments of western New York contain many mesoscopic-scale structures including joints that can be systematically related to the Alleghanian Orogeny.
Based on the nonorthogonality of cleavage and joints, the Alleghanian Orogeny in the Finger Lakes District of New York consists of at least two phases which Geiser and Engelder (1983) correlate with folding and cross-cutting cleavages in the Appalachian Valley and Ridge. To the southeast of the Finger Lakes District the earlier Lackawanna Phase is manifested by formation of the Lackawanna syncline and Green Pond outlier and the development of a northeast-striking disjunctive cleavage within the Appalachian Valley and Ridge mainly from the Kingston Arch of the Hudson Valley southwestward beyond Port Jervis, Pennsylvania (Fig. 1). Within the Finger Lakes District, New York, a Lackawanna Phase cleavage is absent; and one finds instead a cross-fold joint set which is consistent in orientation with a Lackawanna Phase compression. In bedded siltstone-shale sequences (i.e. the Genesee Group) this cross-fold joint set favors development in the siltstones (Stops 1 and 2). The Main Phase is seen as the refolding of the Lackawanna syncline and Green Pond outlier, as well as the development of the major folds in central Pennsylvania. Main Phase structures within the Finger Lakes District include an east-west striking disjunctive cleavage in the Tully Limestone (Stops 4 and 5), a pencil cleavage in the Geneseo shales (Stop 4), deformed fossils in the Genesee Group (Stop 1), and s-fold joints which are orthogonal with the cleavage and deformed fossils in shales (Stop 1) (Engelder and Engelder, 1977; Engelder and Geiser, 1979, 1980, 1984). Outcrops of Tully Limestone at Ludlowville (Stop 5) contain a Main Phase disjunctive cleavage which truncates nonorthogonal Lackawanna Phase cross-fold joints, showing that the Lackawanna Phase predates the Main Phase (Engelder, 1985).
Many outcrops of the Appalachian Plateau contain more than one cross-fold joint set (Fig. 2). Those cross-fold joints attributed to the Lackawanna Phase strike counterclockwise from those attributed to the Main Phase. Cross-cutting cleavages in northeastern Pennsylvania have the same relationship with the later shortening event clockwise from the earlier event (Fig. 1). One exception to this rule was discovered recently by Scott (1986) who has documented two shortening directions in the Tully Limestone at Portland Point which is 3 km SSE of Ludlowville. At Portland Point the later shortening direction appears to be counterclockwise from the direction of the earlier shortening event
This field trip will examine the relationship between lithology and jointing. During a study of regional joints in the vicinity of Ithaca, New York, Sheldon (1912) recognized that certain joint sets favored certain lithologies. Strike joints were common in shales but less well-developed in interfingered siltstone beds. In the same region of the Appalachian Plateau, Parker (1942) noted that plumose markings were rare on strike joints but commonly occurred on cross-fold joints. These studies and those elsewhere (e.g. Stearns, 1968; Nelson and Stearns, 1977) make it clear that the host lithology is an important parameter in influencing the development of regional joint sets as well as their surface morphology.
The five stops of this trip will view the same stratigraphic section that Sheldon (1912) examined. The major units include the Genesee Formation (deWitt and Colton, 1978) or Genesee Group (Van Tyne, 1983), the Tully Limestone, and the Hamilton Group (Van Tyne, 1983). Figure 3 shows deWitt and Colton's (1978) stratigraphic column for the Genesee Formation. The first three stops will examine the Ithaca Member of the Genesee Formation. Stop 4 will examine the Tully Limestone, Geneseo Shale Member, and the Penn Yan Shale Member. Stop 5 will examine the Moscow Shale of the Hamilton Group and the Tully Limestone.
Three general lithologies will be examined: a bedded siltstone-shale sequence (the Ithaca Member), a homogeneous shale (the Geneseo Shale Member and Moscow Shale) and a limestone (the Tully Limestone). Each of these three lithologies has a characteristic joint-orientation pattern and characteristic surface morphology. In addition, surface morphology varies among the various cross-fold joint sets discussed in Sheldon (1912), Parker (1942), and Engelder and Geiser (1980). Surface morphologies have been used to make the case that the cross-fold joint sets mapped by Engelder and Geiser (1980) are fundamentally different from each other.
Within the Appalachian Plateau evidence is overwhelming that the joints formed in extension rather than shear (Engelder, 1982). Surface morphology on joints is distinct from slickensided surfaces on shear fractures. The pattern on joints is called a plumose structure; it constitutes all "delicate tracery of feathery lines" (Woodworth, 1896) diverging from either a straight or sinuous axis. Plumose patterns form during the propagation of a crack (joint) with motion on the crack face normal to the plane of the crack. By the late 19th century geologists recognized that the feather (plume) patterns on joints contained information about the process of joint propagation (Woodworth, 1896). Plumose patterns form on the surface of extension fractures (joints) where the plume records the development of the joint whose rupture front is perpendicular to the barbs of the plume (Fig. 4). Despite the large number of descriptions of the markings on joint faces (Hodgson, 1961; Roberts, 1961; Syme-Gash, 1971; Kulander et al., 1979) none adequately distinguishes the end members of the family of plumose markings observed on the Appalachian Plateau.

3: THE USE OF JOINT PATTERNS FOR UNDERSTANDING THE ALLEGHANIAN OROGENY IN THE UPPER DEVONIAN APPALACHIAN BASIN, FINGER LAKES DISTRICT, NEW YORK

STOP 1: LITHOLOGICAL CONTROL OF CROSS-FOLD JOINTS
IN THE UPPER GENESEE GROUP, WATKINS GLEN, NEW YORK
This roadcut is best viewed in the late morning when the sun strikes the joint surfaces at a high angle. After about 11:30 AM when the joint surfaces no longer receive direct sunlight, the surface morphology is far more difficult to see.
As this roadcut at Watkins Glen was excavated, benches were carved out by taking advantage of the jointed rock. The base of the roadcut is dominated by Upper Genesee Group shales. About mid level in the exposed section thicker siltstone stringers are intercalated with the shale. At the top of the roadcut siltstones dominate. In walking uphill along Route 414 from the town of Watkins Glen, fmd at the base of the roadcut a 15 cm thick siltstone with plume structures nicely developed on a joint face. Stratigraphic levels within the Genesee Group of this roadcut are referenced from the bottom of this 15 cm thick bed. 10 siltstone beds or groups of beds may be used as markers in describing the 34 m thick road cut. Key beds are located according to Table I.
Lithological control is fundamental to the development of joints within the Appalachian Basin as is nicely illustrated by this outcrop. Vertical joints within the shales strike at 341°-343°, whereas vertical joints within the siltstone beds strike at 331°-334°. Although important in controlling joint development, the differences between siltstone and shale within the Ithaca Member of the Genesee Formation are subtle. Figure 5 shows histograms for the grain size distribution and composition of siltstones and shales from Stop 1. At Stop 1 the outcrop criterion for distinguishing a siltstone from a shale is based purely on the orientation of the joint set that a particular bed is carrying. Beds that carry "siltstone" joints have a clay/quartz ratio between 0.71 and 1.06 with more than 25% of the grains greater than 30 microns. Beds that carry "shale" joints have a clay/quartz ratio between 1.21 and 2.80 and less than 20% of its grains greater than 30 microns.
Table I
Bed
Number
Stratigraphic
Level (m from base)
Landmark or
Road Sign
1 | 0 m | "Slow traffic keep right" sign
2 | 4 m | Natural Gas Pipe Line
4 | 16 m | "Village Speed Limit 30 MPH"
7 | 25 m | top portion of thick shale
8 | 27 m | caution sign for deer
Another unusual aspect is the variety of well-developed markings on the surfaces of joints in both the siltstones and shales. A composite of barbs and arrest lines leaves a delicate plumose structure on the surface of joints in siltstone (Bahat and Engelder, 1984). The barbs consist of a fine roughnesses (low relief elements) on the joint surface which were caused by local out-of-plane crack propagation. This roughness forms ridges parallel to the direction of rupture propagation. Out-of-plane propagation is believed to be caused by microscopic inhomogeneities, such as grain boundaries in the siltstone. Because the shale is more homogeneous on a microscopic scale there is less tendency for out-of-plane crack propagation. Hence, the shales show no surface morphology equivalent to plumose structures on the siltstones.
Joint faces within siltstones contain three varieties of plumose patterns: the straight or s-type plumose marking which is displayed in the 19 cm thick siltstone bed (#7) at the 25.7 m level (Fig. 6A); the curving or c-type plumose marking which is best displayed in siltstone (bed #8) at the 29 m level (Fig. 6B); and the rhythmic c-type plumose marking which is displayed on the 44 cm thick siltstone bed (#6) at the 22.4 m level (Fig. 6C). The straight plume has a linear axis parallel to bedding whereas the curving plume commonly has an axis which divides into several branches which in turn may themselves divide. Barbs radiate from the plume axes of both the s-type and c-type plume patterns. The barbs form a fine surface morphology which indicates the direction of rupture propagation with the rupture moving from the plume axis outward toward the edge of the joint.
The plumose structures may be traced backward to their initiation point. Cracks initiate at inclusions within the rock such as fossils, concretions, ripple marks, or microcracks. These inclusions are stress risers that permit the magnification of a far field stress to overcome the local tensile strength of the rock. At Stop 1 most initiation points are bedding plane boundaries. The 19 cm thick siltstone stringer (#7) at the 25.7 m level contains four or more initiation points at the top of the bed. In contrast, the 44 cm thick stringer (bed # 6)shows initiation points on the bottom of the bed. Higher in the section (= 29 m level) siltstone beds are cut with initiation points within the bed.
A feature found on both shale and siltstone joints are arrest lines. These features mark the termination of propagation of individual cracks. The 4 m thick shale bed, at the 24 m level, shows a large arrest line curving on the joint face with the convex side of the line facing in the direction of joint propagation (NNW). This same shale bed contains the 19 cm thick siltstone stringer (bed #7) displaying an s-type plume pattern. Barbs of the s-type plume on the siltstone stringer diverge in the direction of propagation which is toward the NNW and compatible with the large arrest line within the shale. Within the same shale bed another joint terminates against the arrest line after propagating in the SSE direction as is again indicated by the barbs on the s-type plume within the siltstone stringer (bed #7). Arrest lines can be observed on the 44 cm thick siltstone bed (#6) at the 22.4 m level. These arrest lines are part of the rhythmic c-type plume pattern found on joint faces cutting siltstone beds. Here the arrest lines are spaced less than 1 m apart in contrast to those on the thick shales which are separated by more than 50 m.
The closely spaced arrest lines in bed #6 may be interpreted in terms of a jointing mechanism. The deeper portion of the Appalachian Basin is undercompacted (Engelder and Oertel, 1985). Such undercompaction indicates that abnormal pore pressures once prevented normal pore collapse. Pore pressures approaching the weight of the overburden are capable of initiating and driving natural hydraulic fractures. The closely-spaced arrest lines within the siltstone beds suggests a cyclic rupture. Two phases of the cycle are a slow build-up of pore pressure followed by a fast decrease accompanying the incremental propagation of a joint This process repeats many times to leave a set of closely-spaced arrest lines.
The c-type plumes are found on joints striking at 331°-333°, (this is considered the normal orientation for joints in siltstone layers at Stop 1) whereas small siltstone stringers (i.e. bed #7) in thick shales show the s-type plumes with joints striking at 341° The s-type plume in bed #7 is believed to indicate a rapid rupture that extended more then 50 m in a horizontal direction. The length of the rupture is indicated by the distance between the initiation point 50 m to the SSE and the large arrest lines within the 4 m thick shale layers. In contrast, the c-type plumes give the impression of a slower less decisive rupture. Arrest lines spaced at less than a meter on the 332° joints confirm this notion.
The difference between joint propagation in the shales and joint propagation within the siltstones is further understood by placing the timing of their propagation within a regional context. On upper benches of the outcrop (at the 34 m level) deformed crinoid columnals show that the layer parallel shortening (LPS) during the Alleghanian orogeny was oriented at 341°. Geiser and Engelder ( 1983) interpret this LPS direction as a principal compression direction during the Main phase of the Alleghanian Orogeny. At Watkins Glen the othogonality of shale joints and LPS indicated by deformed fossils suggests that the shale joints propagated during the Main Phase. If this is so them when did the joints within the siltstone beds propagate?
The joints within the siltstone are believed to precede those within shales. First, early joints at Ludlowville, New York (Stop 5) appear to be cut by Main Phase cleavage. These joints strike a few degrees counter clockwise from the Main Phase LPS. Secondly, in a deeply buried siltstone-shale sequence the siltstones are known to show a lower least principal stress compared to shales. If joints are hydraulic fractures propagating under high fluid pressures, the joints in beds with the lower least principal stress will propagate first. Third, the preferred orientation of chlorite within the siltstone beds is compatible with a LPS counterclockwise from the LPS affecting the shales (Oertel and Engelder, 1986). Elsewhere in the central Appalachians, the Lackawanna Phase LPS precedes the Main Phase LPS with a counterclockwise compression (Fig. 2).

STOP 2. MULTIPLE JOINTING IN THE UPPER GENESEE GROUP AT WATKINS GLEN
This location just west (east?) of Watkins Glen also consists of benches in a roadcut. A 4-5 m thick siltstone unit is the major component of each bench. Here the relationship between lithology and jointing is less straight forward than was found at Stop 1.
A 3-m thick siltstone within the upper bench contains cross-fold joints (334°-336°) which propagate to but not across the contact between the siltstone and the adjacent shales. This again demonstrates how lithological changes act to stop the vertical propagation of joints. However, joints originating within the underlying shale cross into the overlying interface to propagate upward into the siltstone. This latter behavior breaks the rule that lithological changes stop vertical joint propagation. Note that joints within the siltstone are planar whereas the joints in the adjacent shale are less planar.
Both the siltstones and shales of the upper bench carry joints of more than one orientation. At the very south end of the upper bench the siltstone contains joints of two orientations. A joint striking 336° is on top of a joint striking at 343°. Close examination suggests that the joint striking at 343° propagates in a layer that looks more like a shale than the adjacent layer. There are subtle changes in lithology within units that at a distance appear homogeneous to jointing. The shale package below the 3-m thick siltstone has siltier units with joints striking at 336° versus shalier units with joints at 348°.
The lower bench of this roadcut contains three cross-fold joint sets with strikes of 334°, 341°, and 004°, respectively. The three joint sets are best viewed just downhill from the north 414 - east 79 sign within a face of the lower bench. All three joints have propagated in the same 4 m thick unit of siltstone beds. Again the rule of lithological selectivity of jointing is not obeyed. If it is accepted that the sets at 334° and 341° correlate with those at the previous stop, then the set at 004° requires explanation. We must also wonder if it is possible to fit three cross-fold joint sets into a regional context.
Geologists are in general agreement that tectonic joints are found as othogonal partners to fold axes within fold thrust belts. The exact details concerning the mechanism for maintaining orthogonality are subject to debate. Engelder and Geiser (1980) took the position that, as fold axes curved around the Central Appalachian trend, members of a single joint set on the Appalachain Plateau changes orientation to maintain a position subnormal to local fold axes. A single joint set may then be traced along strike of the Plateau fold belt for more than 100 km. Nickels en and Hough ( 1967) took the opposite view which was that one joint set did not change orientation along strike. Rather individual joint sets maintained a constant orientation within a smaller region and a local joint set of another orientation propagated to maintain "orthogonality" to the local folds of a different orientation.
100 km east of the Watkins Glen area the 004° orientation is far more common than at Watkins Glen. By Engelder and Geiser's (1980) interpretation the 004° joints in this outcrop are stray cross-fold joints with no tectonic significance. By Nickelsen and Hough's (1967) interpretation the 004° joints are the western most manifestation of the common cross-fold joint set found in the vicinity of Binghamton, New York. The distance between outcrops is too large to resolve this issue.

STOP 3: LITHOLOGICAL CONTROL OF MULTIPLE JOINT SETS
IN ITHACA SHALE OF THE GENESEE GROUP AT TAUGHANNOCK STATE PARK
This outcrop contains four of the cross-fold joint sets which may be observed in the Finger Lakes district. Despite the complicated pattern of jointing the rule for the silt-shale jointing holds up with joints in the siltstone striking counterclockwise from joints within the shales. Step down into the stream bed just north of the bridge across Taughannock Creek. At this point several benches have been cut into the northeast back of the creek. Joints on those benches fall in three sets: 339°, 345°, and 352°. A fine example of a siltstone joint (340°) over a set of shale joints (352°) is seen just north of this point. Further upstream a joint strikes at 301°.
Here the question is which joint sets correlate with those seen at Stops 1 and 2? Does a 333° joint in siltstone at Stop 1 correlate with a 340° joint in siltstone at Stop 3? Likewise, does a 342° joint in shale at Stop 1 correlate with, say, a 352° joint in shale at Stop 3? Or should a correlation be made strictly on common orientation such as the 342° at Stop 1 with the 340° at Stop 3? These are questions that will probably never be answered to everyone's satisfaction.
Strike joints (080°-090°) are irregular in plan view and widely-spaced in this outcrop. This irregular form is common for strike joints throughout the Appalachian Plateau. Strike joints are believed to propagate upon uplift and, hence, be very late in origin.

STOP 4: DISJUNCTIVE CLEAVAGE AND JOINTING
IN THE TULLY LIMESTONE AND GENESEO SHALE AT TAUGHANNOCK FALLS STATE PARK
Taughannock State Park features a U-shaped hanging valley and 50 m waterfall at the head of a 1.5 km-long gorge cut to the level of Cayuga Lake. Outcrops within the park consist of the Tully Limestone and Geneseo shales in the stream bed of Taughannock Creek and the lower portion of the Genesee Group (the Geneseo shales) exposed on the walls of the gorge. 200 m upstream from the park entrance bedding surfaces of the Tully Limestone may be examined in the stream bed. In another 800 m upstream the stream bed becomes the Geneseo shale.
On beds of the Tully Limestone, a disjunctive cleavage is well developed. The cleavage gives a faint herringbone pattern on the gray pavement of the Tully Limestone. Cleavage domains appear as a wavy trace of a dark selvage against the light gray background of Tully Limestone. Individual selvages extend for 10s of cm before ending in many fine branches. The microlithons of Tully Limestone are 5 to 15 cm thick. The spacing of cleavage domains constitutes a weak cleavage according to the classification of Alvarez and others (1978). A general trend for the cleavage of 077° is normal to the compression direction of the Main Phase of the Alleghanian Orogeny in the vicinity of Ithaca, New York. Because the cleavage is wavy any one cm length of selvage might be misoriented from the 077° trend by as much as 15°. Close examination of the selvages will reveal short stylolites pointing in the direction of the Main Phase compression at about 347°. At Stop 1 the compression direction was 341°.
The contact between the Tully Limestone and the Geneseo shales gives a fine example of the relationship between disjunctive cleavage in the limestone and the development of pencil cleavage in the shales. Best examples are found on the north side of the creek about 400 m from the park entrance. The long axes of the pencils within the Genesee Shales trend at 077° which parallels the strike of disjunctive cleavage within the Tully Limestone. Here the pencils are blocky rectangular solids rather than the long and skinny shape as found in other outcrops of the Appalachian Plateau. The two short dimensions of a pencil cleavage consist of bedding and a disjunctive cleavage normal to bedding.
At Stop 4 the Tully Limestone contains none of the cross-fold joints found within the Genesee Group at Stops 1, 2, and 3. Limestone affects joint development in a different manner than siltstone and shale. The best developed joints in the Tully Limestone are several sets of en echelon cracks found on the second bench of Tully Limestone about 300 m from the park entrance. Individual cracks within the en echelon set strike at 316° whereas the shear couple indicated by the en echelon zone strikes at 324°. There seems to be no clear relationship between these en echelon cracks and the Alleghanian Orogeny.
On walking upstream Taughannock Creek makes a righthand turn at the point where cross-fold joints appear within the Genesee shales. Here it is common to see later subparallel cross-fold joints (=330°) curving into and abutting earlier cross-fold joints (=340°). This abutting of cross-fold sets is not found at other stops and is difficult to explain in the context of a two phase Alleghanian Orogeny.
The rocks in the walls of Taughannock Creek gorge present an example of the behavior of cross-fold joints within thick (> 50 m) sequences of homogeneous shale. From the Taughannock Creek the tectonic joints can be traced continuously up the valley wall for a large fraction of the exposure of the Geneseo shales. The joints propagate so that their vertical dimension is as large or larger than their horizontal (parallel to strike) dimension. In contrast with Stops 1, 2, and 3 where vertical joint growth was arrested by bedding interfaces, vertical joint growth was not impeded in the Geneseo Shale. This is best seen at the point where the gorge makes a right turn 1,000 m from the park entrance. After rounding the right turn in the creek bed, look up on the southeast side of the gorge. Here cross-fold joints are displayed on the southern wall whereas strike joints are displayed on the eastern wall. Across the creek from this point cross-fold joints can be seen on the northern wall. The cross-fold joints are better developed and more closely spaced. This same effect can be seen at the falls where (facing the falls) rocks to the left of the falls show cross-fold joints whereas those to the right of the falls show widely spaced strike joints. Note that cross fold joints become irregular within 50 m above the top of the Tully Limestone.
Engelder (1985) distinguishes tectonic joints (those caused by abnormal pore pressures during tectonic compression) from release joints (those caused by erosion and controlled in orientation by an pervasive fabric such as disjunctive cleavage). At the right turn in Taughannock Creek the cross-fold joints are tectonic joints and the strike joints are release joints. Evidence for the development of abnormal pressures during tectonic (cross-fold) joint propagation include the undercompaction of the Geneseo shales (Engelder and Oertel, 1985). Note that good examples of release joints are common in the creek bed upstream from this point In general the release (strike) joints tend to be less regular in profile than tectonic (cross-fold) joints.

STOP 5: THE RELATIONSHIP BETWEEN DISJUNCTIVE CLEAVAGE AND JOINTING
IN TULLY LIMESTONE AND THE UPPER HAMILTON GROUP IN SALMON CREEK AT LUDLOWVILLE, NEW YORK
Rocks within this outcrop include the Tully Limestone (in the bed of Salmon Creek) above the Upper Member of the Hamilton group (seen below the falls). The major mesoscopic structure within the Tully Limestone is a spaced solution cleavage indicating a compression direction of about 005°. Within just about 4 km between Stop 4 and Stop 5 the compression direction as indicated by cleavage has changed by more then 20°. This is one of the most abrupt changes in LPS within the entire New York Plateau. Less than 2 km south of this outcrop the Tully Limestone is cut by several faults as seen in the Portland Point Quarry. Here local stuctures overprint a relatively homogeneous strain pattern.
Calcite filled veins striking between 340° and 345° dominate within the Tully Limestone of this outcrop. These veins seem to be cut by the spaced cleavage indicating that the veins propagated first. This cross-cutting relationship is taken as evidence that 345° joints are Lackawanna in age whereas the cleavage correlates with the Main Phase deformation.
Overcoring tests at this outcrop show a residual maximum compressive stress normal to the trend of the cleavage (i.e. 005°) (Engelder and Geiser, 1984) (Fig. 7). This residual stress is believed to have been locked into the Tully Limestone during the Main Phase of the Alleghanian Orogeny.
In the pavement of the stream below the falls the Hamilton Group carries joints striking between 70° and 75°. On the eastern wall of the falls just under the Tully Limestone 340°-345° joints are well developed in the Hamilton Group.
On the far side of the stream a few trilobites may be seen weathering out of the polished surface of the stream bed.

4: FACIES AND FOSSILS OF THE ONONDAGA LIMESTONE IN CENTRAL NEW YORK
HOWARD R. FELDMAN
Biology Department
Touro College
New York, New York 10036
RICHARD H. LINDEMANN
Saratoga Springs, New York 12866
Four members of the Onondaga limestone are recognized in the central part of New York State: Edgecliff, Nedrow, Moorehouse, and Seneca. Detailed descriptions of these members may be found in Oliver (1954, 1956) and Feldman (1985). Paleocommunity analyses of the non-reefal aspects of the Onondaga Limestone have been made by Lindemann (1980) and Feldman (1980) while Lindemann and Feldman (1981) have summarized the stratigraphy, lithofacies and paleocommunities of the Onondaga in the Syracuse area. We believe that the formation in this area has been studied thoroughly, consequently, the purpose of this trip is to sample the fauna in order to: [1] Become familiar with the fossils that are characteristic of the Onondaga, and [2] Attempt to correlate the various taxa with their paleoenvironments. This trip, therefore, will concentrate on collecting the fossils of the Onondaga Limestone in the Syracuse area.
The most abundant invertebrate fossils of the Onondaga which lend themselves to collecting in this extremely dense limestone are the brachiopods and corals. Brachiopod collecting is usually best accomplished in the shaley Nedrow Member, at the base of shale lenses, followed by well weathered Moorehouse and Seneca strata. Corals are most abundant in the Edgecliff Member. Since the Onondaga weathers very slowly it is best to locate bedding planes which have not been touched for several years, if possible.

4: FACIES AND FOSSILS OF THE ONONDAGA LIMESTONE IN CENTRAL NEW YORK

STOP 1. Onondaga Indian Quarry
Park on the road shoulders and walk into the south end of the quarry which lies between Quarry Road and the Interstate.
NOTE: This quarry is on the Onondaga Indian Reservation. Do not, under any circumstances, enter without prior permission from the Tribe!
The quarry's south end is floored by the Edgecliff Member. Above this about 13' of Nedrow is exposed (type section). The Moorehouse is 19' thick and is overlain by an incomplete section of the Seneca Member. The Tioga Bentonite horizon is evident as the glacially scoured surface above the quarry's northeast wall where it forms a reentrant high in the southeast wall (it can be located between two chert horizons).

STOP 2. Entire Edgecliff and lower Nedrow
Return to Route 11 and park in the lot on the road's west side. Walk across the road to the outcrop between Route 11 and the I81 exit ramp.
The entire Edgecliff and lower Nedrow are exposed here in a weathered condition which may be more suitable for collecting than the quarry exposures.

STOP 3. Jamesville Quarry
Continue along the entrance road and stop at the quarry office.
This is reputed to be the largest quarry in New York State. Hard hat and prior permission are required. The entire thickness of the Onondaga, from the phosphatic "Springvale Sandstone" to the Seneca and Marcells Shale, is exposed near the quarry's southeast corner. However, quarry operations have left only the "Springvale," Edgecliff and Nedrow section readily accessible. The Tioga Bentonite and Seneca/Marcellus at the quarry top can be safely seen only from a distance. Exercise extreme caution in proximity to the quarry walls; hard hats offer little protection from large falling rocks.

STOP 4. Split Rock Quarry
Continue to the end of Split Rock Road and into the quarry entrance.
This is the type section of the Edgecliff Member which is named for Edgecliff Park, located just to the west. The member's full thickness of 2.3 m is exposed in the upper areas of the main quarry and its erosional base is marked by the presence of phosphate nodules. It is interesting to note the pronounced difference between the "Springvale" horizon here and in the Jamesville Quarry. In the southern quarry wall, 3 m of Nedrow are exposed, but the top of the Nedrow has been removed by glacial scour.

5: STRATIGRAPHY AND PALEONTOLOGY - AROUND CAYUGA LAKE ONCE AGAIN
THOMAS X. GRASSO
Geoscience Department
Rochester, NY 14623-5780
JONATHAN W. HARRINGTON
Harrington Associates
Consulting Geologists
390 Clark St. Ext.
Groton, NY 13073
WILLIAM T. KIRCHGASSER
Potsdam, NY 13676
When the Association last met at Cornell on May 9, 1959, the three of us were soon to be graduate students at the University. The classic Devonian localities visited on Trip C were our formal introduction to a succession of rocks that has enlightened and challenged generations of students. Perhaps nowhere else in the State can such a variety of platform, slope and basin facies and faunas of the Catskill Delta be so profitably seen on a one-day excursion. Much progress has been made in understanding these rocks in the past 27 years and our purpose today is to retrace the route of Trip C in light of subsequent study. The advances in lithostratigraphy, paleoecology and goniatite and conodont biostratigraphy have been particularly notable. It seems especially appropriate that in the 150th Anniversary year of the founding of the New York State Geological Survey, we return to the geographic center of the Devonian outcrop and the succession described in the famed district reports of Vanuxem (1842) and Hall (1843). The sequence of stops of the 1959 trip is followed and an optional stop (Stop 7) in the Renwick Member near Ithaca, has been added (Fig. 1). The stop descriptions in the 1959 Guidebook have been recast and revised where appropriate and discussions of economic and environmental factors have been added. Recent summaries with references to work since 1959 are Rickard (1975, 1981), Oliver and Klapper (1981), Woodrow and Sevon (1985) and Kirchgasser and others (1985).

5: STRATIGRAPHY AND PALEONTOLOGY - AROUND CAYUGA LAKE ONCE AGAIN

Exposure of Sherburne Formation on left.

Willow Creek
At this locality deWitt and Colton (1978) measures 11 feet of Geneseo, 88 feet of Penn Yan, 78 feet of Sherburne and 8 feet of Renwick. The Tully Limestone forms a waterfall just east of the road.

STOP 1A. TAUGHANNOCK FALLS STATE PARK.
LOWER FALLS - MOSCOW SHALE/TULLY LIMESTONE/GENESEO SHALE.
No Hammers. Collecting is not permitted in the State Park but will be possible at a similar section across the lake at Portland Point (Stop 6). Five beds of the TULLY FORMATION are exposed in the falls and cm.ankment. The comments on lithologies and benthic faunas which follow are based primarily on data from Heckel (1973).
The contact between the CARPENTER FALLS and TAUGHANNOCK FALLS beds is a widespread discontinuity surface that marks a major lithologic and faunal break within the TULLY. The TULLY as a whole records a progressive rise in sea level (Taghanic Onlap) following late Hamilton erosion but the sedimentary controls are complicated by regional tectonism (Heckel, 1973). A major deepening even has been recognized worldwide at about this time (Middle varcus Zone) House (1985), Johnson and others (1985).
The upper CARPENTER FALLS bed consists of thick-bedded burrowed calcilutites with some pelmatozoan calcarenites, which disconformably overlies the WINDOM SHALE of the MOSCOW (several eastern units of the lower TULLY are missing here). The diverse fauna is dominated by brachiopods, including Emanuella, Schuchertella and Atrypa; other fossils include trilobites, styliolines, tentaculites, auloporid corals and ostracods. The main Hypothyridina (H. venustula) bed of the TULLY occurs in this area at the base of the unit.
The TAUGHANNOCK FALLS BED (5 ft.) at the base of the Upper TULLY marks the start of a new depositional regime and the major faunal turnover in the TULLY. The bed consists of well-bedded burrowed skeletal calcilutite with the "knobbly zone" (re-entrant) in the lower part. The fauna is dominated by small horn corals, auloporid corals, styliolines, echinoderms and trilobites. Brachiopods and bryozoans are essentially restricted to the upper part of the bed (Elytha fimbriata Zone); Lower TULLY brachiopods are rare or absent The BELLONA CORAL BED contains rugose, tabulate and auloporid corals including Heliophyllum, Cystiphylloides, Favosites and "Heterophrentis". The MORAVIA BED is a 4 foot ledge of wavy-bedded limestone lithologically and faunally similar to the TAUGHANNOCK FALLS BED.
The FILLMORE BED (6 feet) conformably overlies the MORAVIA BED and consists of interbedded dark shaley calcilutitic limestone and dark calcareous shale transitional to (but separated by a sharp conformable contact) the black GENESEO SHALE. The sparse planktic fauna of the FILLMORE GLEN, which reflects continued rise in sea-level and anoxic bottom conditions, includes styliolines, inarticulates, and rare goniatites.
The boundary between the Middle and Upper varcus Zones is near the top of the MORAVIA BED (Ziegler and others, 1976, Table 3; Klapper, 1981 fig. 2). The three elements illustrated in Fig.8 are the commmon Polygnathus linguiformis, Pol. timorensis, a varcus-type species, and Pol. latifossatus which indicates the start of the Upper varcus Zone. In the goniatite sequence, the Pharciceras amplexum horizon is near the base of the MORAVIA BED but specimens have not been reported from this locality (House, 1962, Kirchgasser and House, 1981). Phar. amplexum correlates with a position at the base of the Pharciceras Stufe (House and others 1985).
The controversy over the position of the TULLY with respect to the Middle/Upper Devonian boundary continues (Kirchgasser and others, 1985, Rickard, 1985). At the time of the 1959 meeting the mid-Genesee (GENUNDEW A LIMESTONE) boundary of Cooper and others (1942), where the goniatite Manticoceras enters, was the accepted position but since 1964, and until recently, the boundary has been placed around the TULLY (Kirchgasser, and others, 1985, Fig. 4). The boundary recommended by Devonian Subcommission (base of Lower asymmetricus Zone) is somewhere in the SHERBURNE and is well above the TULLY.

Travelling over a series of hanging deltas.

STOP 1B. TAUGHANNOCK FALLS OVERLOOK, GENESEE FORMATION (FIG. 9).
The main falls and amphitheater, at the head of a one mile long post-glacial gorge with 200 to nearly 400 foot high walls, display a spectacular but mostly inaccessible section in the upper GENESEO, SHERBURNE, RENWICK and lower ITHACA MEMBERS of the GENESEE FORMATION. The top of the falls (215 ft high) is controlled by resistant siltstones in the SHERBURNE MEMBER and by the jointing. The re-entrant at the crest of the falls remains virtually unchanged since the last major rockfall between 1888 and 1892. Near the base of the falls on the left are altered alnoite dikes in N-S joint planes.
About 90 feet of black GENESEO SHALE is exposed in the walls from the level of the plunge pool to the sharp contact with lighter colored shales and siltstones halfway up the falls. Contacts higher up are not easily defined in their fresh joint surfaces. Recent work by Gordan Baird and Carlton Brett shows that the contact at the top of the black shale band is not the same level as the GENESEO/SHERBURNE contact at Hubbard Quarry to the north (Stop 2) and at Seneca Lake to the west. In the gully .7 miles north of Taughannock (Fig.5), the FIR TREE HORIZON is just above the black shale contact. Above are the siltstones and shales of the HUBBARD QUARRY INTERVAL at the top of which is the LODI HORIZON, which defines the GENESEO/SHERBURNE contact (Stop 2). The HUBBARD QUARRY INTERVAL is a silty wedge at the top of the GENESEO MEMBER which intervenes at the south end of Cayuga Lake between the top of the black shale and the LODI. The FIR TREE and LODI HORIZONS have not been seen at Taughannock. The LODI, at the base of the SHERBURNE MEMBER, should be somewhere close to the lip of the falls .
The black shales and lenticular siltstones of the RENWICK MEMBER form a distinctive band in the walls above the level of the falls, and near the top are the lower siltstones of the ITHACA MEMBER. The RENWICK MEMBER, with the Warrenella beds at the base will be examined at Stop 7.
The goniatite (Epitornoceras and Ponticeras) and conodont distributions through the section in this region are illustrated in Fig. 5. The uppermost GENESEO MEMBER is in the disparilis Zone and the LODI has a Lowermost asymmetricus fauna. Datable conodonts have still to be recovered in this part of the Cayuga Lake section. The proposed Middle/Upper Devonian boundary at the base of the Lower asymmetricus Zone should occur at Taughannock somewhere in the SHERBURNE, above the lip of the falls and below the RENWICK.

Bear left along the west side of the stream.
The Ithaca Formation is exposed in the stream bed. Note the mature nature of the upper portion of Trumansburg Creek.

View east of the glaciated upland.

STOP 2. GENESEO, LODI LIMESTONE, SHERBURNE SECTION, HUBBARD QUARRY, (FIG 10).
The contact between the GENESEO and SHERBURNE MEMBERS is well exposed and accessible in the west wall of the quarry. The limey bands in the lower SHERBURNE are the LODI LIMESTONE, a horizon that defines the GENESEO/SHERBURNE contact.
The upper 12 feet of the GENESEO MEMBER at this locality are the HUBBARD QUARRY beds of Brett and Baird (personal communication, 1985), at the base of which is the FIR TREE Horizon, which here is a bedding plane of pyrite and inarticulate debris exposed at the back of the quarry.
The septarian concretions in the upper black shales of the GENESEO are mostly unfossiliferous but they contain "an interesting variety of minerals: barite, calcite, ankerite, quartz, marcasite, sphalerite, and galena, in order of decreasing abundance." (Cole and others, 1959).
The epiplanktic fauna of the GENESEO near the contact (Styliolina-brachiopod facies of Thayer, 1974) includes: Styliolina sp., Barroisella spatulata, Orbiculoidea lodensis, Schizobolus truncatus, Leiorhynchus quadracostatus, Pterochaeniafragilis, Ponticeras perlatum, Epitornoceras peracutum, fish and plant fragments. The clusters of Leiorhynchus are of special interest because the presence of this western North American genus is evidence of eastward faunal migration during the Taghanic Onlap (Johnson, 1970)
In the siltstones of the lower SHERBURNE MEMBER (and especially in the LODI horizon) the fauna is a mixed assemblage of the Styliolina-brachiopod facies and the benthic Cladochonus fauna of Thayer (1974), Cladochonus sp., Leiorhynchus quadracostatus, Loxonema noe, Palaeotrochus praecursor, Panenka sp., breviconic nautiloids and Ponticeras perlatum occur (Cole and others, 1959). This fauna is well developed at Seneca Lake and has been found in the LODI as far west as the Genesee Valley (Figs. 4,5). Presumably the LODI represents a period of reduced clastic influx or hiatus at the end of a transgressive phase. Cole and others (1959) correctly predicted that the LODI would correlate to the west below the level of the GENUNDEW A (Styliolina) LIMESTONE, the horizon with which it had been correlated earlier.
The goniatite Ponticeras perlatum enters near the top of the GENESEO and ranges through the SHERBURNE to the base of the RENWICK. Specimens may be seen in the black shales around the upper septarian horizon, where they occur with the large involute tornceratid Epitornoceras peracutum, and in the LODI horizon. In Europe these are Pharciceras Stufa genera. Huddle (1981) reported conodonts from the LODI at this locxality but the species were not zonally diagnostic. At Seneca Lake the GENESEO/SHERBURNE contact corresponds to the disparilis/Lowermost asymmetrica conodont Zone boundary, of the upper Middle Devonian (as defined by the Devonian Subcommission)(Fig.5).

Groves Creek
Groves Creek on right with water falls over Tully Limestone. Note elevation of Tully compared to its elevation at Taughannock State Park. Excellent fossil collecting in the upper Moscow below falls.

Offshore bar of Glacial Lake Dana to the south.

STOP 3. FAYETTE TOWN QUARRY, CENTERFIELD LIMESTONE AND LEVANNA SHALE, FIG.11.
This quarry, operated by the town for road material, exposes the upper part of the LEVANNA MEMBER of the SKANEATELES FORMATION and the lower 20 feet of the overlying CENTERFIELD MEMBER of the LUDLOWVILLE FORMATION. Gray (1985) has carefully mapped the CENTERFIELD and subdivided it into several submembers based on detailed stratigraphic tracing of distinctive units. He has named the lower CENTERFIELD member, from Buffalo Creek to Owasco Lake, the YORK SUBMEMBER. The quarry is a good collecting site for the dark shale Leiorhynchus fauna of the LEVANNA and the more normal bottom Tropidoleptus (Hamilton) fauna of the CENTERFIELD.
The LEVANNA is a dark, almost black shale with a typical dark shale fauna of mostly Leiorhynchus, Ambocoelia and chonetids. Common forms include: Leiorhynchus multicostus, Ambocoelia umbonata, Strophalosia truncata, Chonetes scitu/a, Orbiculoidea media, Nuculites, Styliolina fissurella, Tornoceras uniangulare, Lyrioceras, Palaeoneilo, Buchiola halli, Panenka, Pterochaeniafragilis, Bucanopsis /eda, Euryzone rugulata, Geisonoceroides, Michelinoceras and Spyroceras.
Terrestrial plants from lands to the east drifted into this area and their carbonized remains are not uncommon: Drepanophycus (lycopsid), Hostimella, Loganiella (psilopsids), and macerated pieces of the seed.fern Eospermatopteris. Fish remains, especially fragments of the armor plate of Dinichthys halmodeus, have been found.
Fernow (1961) suggested that the LEVANNA was deposited in a relatively high stressed, low energy environment such as relatively deep dysaerobic water and, along with the UNION SPRINGS, OATKA CREEK and LEDYARD Members, may represent the deepest water conditions that existed in Hamilton time along the Cayuga Lake meridian. This is indicated by the fine, dark, carbonaceous aspect of the shale and by the paucity of a well developed, high diversity benthic assemblage of larger, epifaunal invertebrate taxa.
In the lighter-colored, slightly calcareous, worm-riddled bands near the top of the LEVANNA, a more normal benthic fauna occurs with Phacops rana, Mucrospirifer, Mediospirifer and chonetids. Large specimens of Agoniatites vanuxemi has also been found in these layers.
The limey bands record episodes of more aerobic water, thereby allowing the establishment of a more normal benthic assemblage. Although free oxygen content was higher that the enclosing dark shales, it probably was not as high as that which prevailed during CENTERFIELD time.
The lighter-colored, slightly calcareous, drab-weathering YORK SUBMEMBER of the CENTERFIELD in the upper part of the quarry represents the lower part of the member, and is here rich in pelecypods such as Aviculopecten princeps, Actinopteria decussata, Modiomorpha mytiloides, and Leiopteria; and well-preserved brachiopods: Meristella barrisi, Tropidoleptus carinatus, Spinocyrtia granulosa, Fimbrispirifer venustus, and Mediospirifer audaculus. A few favositid and rugose corals may be found at or near the top of the unit
The CENTERFIELD at this locality represents the start of a shallowing upward sequence that does not become fully developed because the section is incomplete. The shallowest facies (peak regression or core CENTERFIELD) at other localities in the Cayuga Lake region is found in the overlying VARICK SUB MEMBER (Gray, 1985). Above this the WHEELER GULLY SUB MEMBER represents a return to slightly deeper water conditions paralleling those that existed in the YORK SUBMEMBER, as discussed below. The overlying LEDYARD MEMBER above the CENTERFIELD mirrors the LEVANNA MEMBER.
The YORK SUBMEMBER represents a transitional environment between the deepest water LEVANNA below and the shallowest water VARICK above. Generally low energy conditions prevailed as indicated by the fine grained lithology. The diverse benthic assemblage suggests well oxygenated water. The presence of an occasional trilobite, with well developed eyes, suggests deposition in the photic zone.

LUNCH STOP-CAYUGA LAKE STATE PARK

The site of Cayuga Bridge.
Cayuga Bridge crossed Cayuga Lake as part of the Great Western Turnpike before what is now US Route 20 was built skirting the north end of the lake. Cayuga Bridge was constructed of wood and joined Bridgeport on the westside of the lake with the village of Cayuga on the east shore. Construction commenced in May 1799 and was completed in September 1800, by the Manhattan Company of New York for $150,000. Its length was 1 mile, and at the time of its completion it was the longest bridge in North America, and perhaps the world. A traveller remarked in 1800 that only 5 years ago "the Indians possessed the shores of the lake, imbosomed in almost impenetrable woods." The first bridge was built on mud sills, the second on piles, the third and last was erected in 1833. It burned sometime thereafter.

STOP 4A. SENECA STONE QUARRY, UPPER SECTION
CHERRY VALLEY/UNION SPRINGS. FIG.12
(Note: Permission must be obtained before visiting this quarry.)
In 1959 only the upper member of the ONONDAGA, the SENECA, was exposed at this location. The quarry had been worked off and on for at least a century, and at that time was being worked on a small scale by Warren Bros. Road Co. to provide crushed stone for bituminous paving. Subsequently purchased by Seneca Stone Corp., the quarry has been greatly enlarged and deepened. The entire ONONDAGA sequence, as well as the overlying UNION SPRINGS SHALE and CHERRY VALLEY LIMESTONE, and the underlying SPRINGVALE HORIZON, ORISKANY SANDSTONE, and uppermost MANLIUS, may now be seen.
Walk west along the upper bedding plane of the CHERRY VALLEY LIMESTONE. This unit has long been famous for its diverse and abundant cephalopods (Ciark,l901; Flower,l936; and Rickard, 1952). Agoniatites vanuxemi and Striacoceras typum are common cephalopods at this locality. Other forms include the tabulate coral, Aulopoa, and the trilobite, Proetus. Please do not attempt to collect from the bedding surface. Loose blocks at the west end of the outcrop provide better collecting.
To the north a low angle thrust fault may be seen cutting the UNION SPRINGS BLACK SHALE and the upper portion of the ONONDAGA. Several structural depressions may also be seen in the quarry wall. These are sag structures produced by local solution of underlying bedded gypsum. These structures are well developed along the plateau front, near deep valleys where there has been deep ground water circulation (Phillips,1955). They are generally considered to be post-glacial in origin (Gilbert,l891; Fairchild, 1909)

STOP 4B . SENECA STONE QUARRY, LOWER SECTION
ONONDAGA/ORISKANY/MANLIUS SECTION, FIG.12.
As we pass beneath the crushing plant the TIOGA METABENTONITE BED can be readily see. In 1959 this horizon was approximately one foot above the quarry floor. The TIOGA METABENTONITE provides an excellent time marker. Eastward from here it is found progressively nearer the top of the ONONDAGA, indicating the time-transgressive nature of the unit --older in the east, younger in the west.
The floor of the main quarry is on the ORISKANY SANDSTONE and the overlying lowermost EDGECLIFF MEMBER of the ONONDAGA. The nodular phosphatic SPRINGVALE HORIZON may be observed, as may the uppermost beds of the MANLIUS FORMATION. The complete EDGECLIFF, NEDROW, MOOREHOUSE and SENECA MEMBERS of the ONONDAGA are exposed in the highwall. In the quarry floor loose blocks of EDGECLIFF and ORISKANY provide excellent collecting. Particularly abundant in the ORISKANY are the large brachiopods Costispirifer arenosus, Acrospirifer murchisoni, Rensselaeria ovoides, and Hipparionyx proximus.
To the west in Ontario the SPRINGVALE consists of a sandstone lithologically very similar to the ORISKANY (from which it was derived by reworking) and to the basal "Zone A" sandstone of the EDGECLIFF. No sandstone of SPRINGVALE age is present in New York (Hodgson, 1970). However, a nodular phosphatic horizon, representing very slow rates of sedimentation, is well developed here and at Yawgers Woods (Stop 5). Depending on the locality, this horizon rests either on the ORISKANY or on older Silurian dolomites.

STOP 5. YAWGERS WOODS, MANLIUS/ORISKANY/ONONDAGA SECTION, FIG.13.
Here the resistant ORISKANY SANDSTONE, a single bed 4 feet thick, outcrops in the woods a half mile rest of the road, where it forms a low escarpment facing west. A few feet of MANLIUS (ONLEY MEMBER) LIMESTONE limestone can be seen below it and one or two feet of the basal ONONDAGA (SPRINGVALE EDGECLIFF) LIMESTONE rest on top.
In a creek less than 1000 yards to the south the ORISKANY is absent and the ONONDAGA lies directly and disconformably on the MANLIUS. In 1959, the ORISKANY was thought to be absent from the opposite side of the lake westward to Buffalo. Its distribution can now be extended west to the Canoga exposure (Stop 4). The sandy SPRINGVALE horizon in the base of the ONONDAGA has often been mistaken for the ORISKANY in the areas where the latter actually is lacking.
This and a nearby locality are among the oldest known and most famous of American Devonian fossil localities. It was visited as early as 1810 by DeWitt Clinton, later governor of the state, on his return to Albany from an expedition to explore the route of the then proposed Erie Canal (1817-1825). The quote below is extracted from Clinton's "Private Canal Journal" found in Campbell (1849, p. 167-168).
"August 12th., Sunday. We left Ithaca at five ....... We dined at Henry Moore's tavern four miles from Cayuga Lake ........... Moore is a Republican, as all cm.grants from Suffolk county are ...
About half-a-mile from his house, and three and-a-half from Cayuga Lake, there is on Lot 69 of the Cayuga Reservation, containing 240 acres and owned by him a ledge of rocks and stones extending a mile in a parallel direction with the lake. The higher stratum is composed of limestone (Onondaga), and the next adjoining one of sandstone (Oriskany) cm.edded with marine substances. There is but one stratum of sandstone, of the thickness of two or three feet, and below and beneath as well as above it there is limestone (lower ls. =Manlius). The sandstone contains several marine shells, which appear to be strange, and I should therefore pronounce them oceanic. There are littoral ones also, such as scallops (probably Costispirifer arenosus) and in one instance a periwinkle (Platyceras?) was found and sent to Peale's Museum in Philadelphia. One strange substance is larger than a scallop, and one is like a horse shoe in miniature (Hipparionyx proximus) ... This collection of sandstone demonstrates the existence of the ocean here."
A few years later (1815), Clinton remarked of these fossils: "These petrifactions are worthy of a more minute examination. I have no doubt but that a very interesting set of shells might be made from this immense stratum of sandstone."
In 1819 David Thomas of Aurora noted that the fossils in the sandstone are mostly in the bottom of the bed, due to the "shells sinking more speedily than the sand" in the Flood, i.e., diatactic settling of the sedimentologists!
Benjamin Silliman sent some fossils from Yawgers Woods to Alexandre Brongniart in Paris in 1820. Brongniart was unable to name them: " ... the sandstones of Cayuga, containing terebratulids which I shall perhaps be able, at some future time, to give you the exact name." By 1829, however, Brongniart was able to correlate, more or less correctly, "le gres blanc de Cayuga:" with sandstones of Devonian age in Europe, but it was many years before Conrad, Hall, and Vanuxem figured and described the fossils of the ORISKANY.
Fossils are scarce in the MANLIUS at this locality. The fauna is small, consisting of benthonic forms indicative of hypersaline conditions: Howellella vanuxemi, Brachyprion varistriata, Schuchertella inter striata, Tentaculites, Leperditia alta.
The fauna of the ORISKANY is characterized especially by large brachiopods in enormous numbers, with occasional pelecypods and gastropods but few other forms: Costispirifer arenosus, Rensselaeria ovoides, Acrospirifer murchisoni, Hipparionyx proximus, Cosstellirostra peculiaris.
Only the lowest one or two feet of the ONONDAGA LIMESTONE cap the ORISKANY at Yawgers Woods, representing the basal SPRINGVALE sand horizon (Zone A of Oliver, 1954), and the lowest beds of the EDGECLIFF MEMBER (Zone C of Oliver). Collecting is poor, but some loose blocks of the SPRINGVALE in the field at the east edge of the woods contain corals and the black, phosphatic sandy nodules characteristic of the SPRINGVALE. Purple fluorite is sometimes found in intradissepimental cavities in the corals. The SPRINGVALE represents weathered ORISKANY reworked by the westwardly-transgressing Onondaga sea.

Village of Union Springs.
On right is the Union Springs High School gas well. This well, a stepout of the Queenston West Auburn Field, provides much of the energy utilized by the school.

Union Springs Quarry
On the left in the old Union Springs Quarry is exposed the Cherry Valley/Union Springs/Onondaga sequence. Note old quarrymen's houses constructed of Onondaga Limestone on the right.

Passing the site of Cayuga Castle, "Goi-o-Gouen"
Two miles east is the site of Cayuga Castle, "Goi-o-Gouen", a principal Cayuga Indian village destroyed in the Sullivan Campaign September 23, 1779. This was also the site of an early Jesuit Mission.

Enter the Hamlet of Levana.
The type exposure of the Levana Shale is in the cliff along the lake shore.

On the right is the Aurora Inn (1833).

Wells College.
On the right (left?) is Glen Park, built (1852), home of Henry Wells, founder of American Express (1850), Wells Fargo (1852) and Wells College (1868).

Popular Ridge Road
On left pass Popular Ridge Road , which leads to Moonshine Falls, an excellent exposure of Ledyard Shale and Centerfield Limestone.

View south to Ithaca
Portage Escarpment in the distance.

Cross Salmon Creek
An excellent example of barbed drainage produced by stream diversion.

STOP 6. PORTLAND POINT QUARRY.
MOSCOW/TULLY/GENESEO SECTION. FIGS.l4,15.
(Specific stops within this quarry will depend on the stage of operations at the time of our visit).
This quarry, the only commercial TULLY LIMESTONE mine in New York, contains one of the most fossiliferous exposures in the Cayuga Lake Basin. Over 100 species of corals, bryozoans, crinoids, brachiopods, pelecypods, gastropods, cephalopods, and trilobites, have been collected from the top few feet of the MOSCOW SHALE exposed in the quarry floor.
Until 1948 Penn-Dixie Cement Company operated a large cement plant on the Cayuga Lake shore. Cement was transported by barge up Cayuga Lake to the Erie Canal system. Limestone mined in this quarry was conveyed to the plant by aerial cableway. Since 1961 the mine has been operated by Cayuga Crushed Stone, Inc. Material is utilized for aggregate, concrete, bituminous material and rip rap. The level of mining and extent of operation has changed dramaticly since the 1959 NYSGA visit to this quarry. Reserves in the present mine are virtually exhausted. An extention of the mining operation is now being developed which will provide limestone to the southern Finger Lakes for the next 10 to 15 years. Limestone will be mined north of Portland Point Road, and will be transported over the road by conveyor belt to the existing crushing plant (Fig.14).
Of particular significance in this mine is the unusual thickness of glacial overburden and black shale that is economically stripped in order to remove limestone. In the southern portion of the mine, over 15 feet of glacial till and 40 feet of GENESEO SHALE must be stripped to remove 10 feet of capstone (a transitional sequence of interbedded limestone and shale -the FILLMORE MEMBER of Heckel( 1973) and 19 feet of TULLY LIMESTONE. To control product quality the capstone must be isolated by selective mining. The favorable location of this quarry for marketing stone throughout the Southern Tier makes this extreme depth of stripping economically feasible. Most of the quarry floor is now occupied by spoil piles of GENESEO SHALE. This material will be backfilled against the highwall during reclamation. In the near future only in those areas mined prior to 1975 will bedrock exposure remain.
The quarry is situated on the crest of the Fir Tree (Portland Point) Anticline. The south limb of this fold is cut by a low-angle thrust fault overthrust to the northwest. On the east side of the quarry are several kimberlite dikes. These dikes, described by Sheldon, 1921; Martens, 1924; and Broughton, 1950, vary from 6" to 1'5" in width and strike parallel to the prominent N 5 W joint set. Glacial striae are exposed on TULLY LIMESTONE surfaces at the north end of the quarry.
The black, bituminous GENESEO SHALE is sparsely fossiliferous, but contains a mixture of pelagic marine fossils (Orbiculoida.e, Styliolina fissurella, linguloids, Paracardium, Leiopteria, Tornoceras uniangulare), freshwater fish (Dinichthys, crossopterygian scales), and land plants (Aneurophyton).
The TULLY LIMESTONE is fossiliferous, but fossils are hard to extract. The guide fossil Hypothyridina venustula is found in clusters in the lower part of the basal CARPENTER FALLS MEMBER. The thin dark shaly BELLONA CORAL BED, in the upper part of the TULLY, is a widespread datum plane from Skaneateles Lake across the Cayuga Lake Basin nearly to the western limits of the Tully east of Canandaigua Lake. The corals of this zone -- Heliophyllum, Heterophrentis, Siphonophrentis, Cystiphylloides, Favosites, and Alveolites, are not found in the TULLY outside of this bed, and represent a recurrence of Hamilton forms,
The upper 5 feet or so of the MOSCOW FORMATION (WINDOM MEMBER) exposed in the quarry floor, is very fossiliferous. The fauna is the typical normal shale Tropidoleptus fauna. Especially abundant or characteristic are: Corals - Amplexiphyllum hamiltoniae, Bethanyphyllum robustum, Cystiphylloides americanum, Eridophyllum archiaci, Favosites hamiltoniae, Favosites turbinata, Favosites arbuscula, Heliophylum halli, Heterophrentis spp., Stereolasma recta, Stewartophyllum intermittens, Trachypora vermiculosa (= T. romingeri, T. limbata; Bryozoa-Fenestre/lina spp. Fistuliporafruticosa, Fistulipora frurcata, Ptilopora striata, Polypora multiplex, Sulcoretepora incisurata, Taeniopora exigua; Brachiopods - Athyris spiriferoides, Atrypa "reticularis" Mediospirifer audaculus, Camarotoechia sappho, Chonetes coronatus, Cryptonella planirostra, Cyrtina hamiltonensis, Douvillina inaequistriata, Elytha fimbriata, Megastrophia concava, Mucrospirifer mucronatus, Pholidostrophia nacrea, Protoleptostrophia perplana, Rhipidomella vanuxemi, Spinocyrtia granulosa, Spinocyrtia marcyi, Stropheodonta demissa, Tropidoleptus carinatus; Gastropods - Naticonema lineata, Platyceras erectum; Pelecypods - Actinopteria boydii, Actinopteria decussata, Aviculopecten princeps, Cypricardella bellistriata, Grammysia arcuaata, Leiopteria greeni, Lyriopecten imerradiata, Modiomorpha mytiloides, Goniophora hamilltoniae, Palaaeoneilo muta, Plethomytilus oviforme; Cephalopods - Michelinoceras sp., Nephriticerina juvenis, Spyroceras sp.; Trilobites - Dechenella rowi, Dipleura dekayi, Greennops boothi, Phacops rana.

STOP 7. RENWICK SECTION.
A continuous section through the RENWICK MEMBER of the GENESEE FORMATION is accessible on the south side of the access road above Lake Street. The section begins close to the base of the RENWICK but the contact with the underlying SHERBURNE siltstones is not exposed.
In the vicinity of Ithaca, the RENWICK MEMBER, as defined by deWitt and Colton (1978), consists of sparsely fossiliferous brownish-black and dark gray shale interbedded with gray silty shale and siltones (some with sole marks) and siltstone-filled scour channels. The RENWICK records a transgression between major stages of delta progradation (SHERBURNE and ITHACA).
The well-known WARRENELLA LAEVIS BEDS (Zone) (Williams 1884; Kindle 1906) which characterize the SHERBURNE/RENWICK transition in this area are well displayed here. This emigrant brachipod from western North America is an important faunal marker around Cayuga Lake but has not been reported farther west in New York. At the foot of Ithaca Falls, in nearby Fall Creek, Williams (1884) and Kindle (1896) describe a diverse fauna from the laevis interval, including the goniatite Ponticeras perlatum (highest occurence of the species) but the fauna here is rather sparse and goniatites have not been seen.
Above the laevis beds are a series of transgressive/regressive cycles marked by black shale band interbedded with siltstones, some with sole markings. The distinctive interval of scour channels (channel-fillings), interpreted by Williams (1881) as iceberg scratchings, is well displayed. de Witt and Colton report channels in this region up to 3 feet deep and 30 feet wide. Scant data indicate southwest trends for the channels and current flow from east to west but with some eastward flow as well (de Witt and Colton 1978, p. A12).
The scour channel interval contains the famous Plumalina beds with the delicate fern-like fronds "called Lycopodites vanuxemi by Dawson, but considered to be allied with the graptolites and named Plumalina plumaria by Hall ... " (Williams, 1881). They are now thought to be either hydroid corals or alcyonarian corals (Sass and Rock, 1975). At the top of the section are dark shales with Lingula and Leiorhynchus. In the early classifications of the section around Ithaca the dark Lingula shales of the ITHACA beds included all of what is now called RENWICK. The RENWICK/ITHACA boundary remains poorly defined. deWitt and Colton recognize 60 feet at the nearby type locality at Renwick Brook, which would place the contact near the top of the scour channel interval.
Exposures farther east along Rte. 13 are in the ITHACA MEMBER. The section around the cloverleaf at the Cayuga Heights exit has been examined but no lithologic or faunal horizons have been found which can be correlated to particular horizons in the gorge sections at Fall Creek, Cascadilla Creek, and farther south. It may be possible to tie the sections together by correlating conodont horizons, if Klapper's subdivision of the Lower asymmetricus Zone can be recognized. Further work on the paleoecology (Thayer, 1974) and biostratigraphy (Kirchgasser, 1985) of ITHACA MEMBER must include taxonomic revision of the faunas, particularly the brachiopods.

6: PALEOENVIRONMENTAL ANALYSIS OF THE FIDDLERS GREEN FORMATION (LATE SILURIAN) IN NEW YORK STATE
RICHARD D. HAMELL
Dept. Geosciences
Rochester, N.Y. 14623
SAMUEL J. CIURCA, JR.
48 Saranac Street
Rochester, N.Y. 14621
The Late Silurian of New York has long been famous for its eurypterid fauna. A number of investigators have dealt with the occurrence of these unique arthropods such as Clarke and Ruedemann (1912), Ruedemann (1916), Kjellesvig-Waering (1958, 1963, 1964), and Ciurca (1973, 1975, 1978, 1982, 1986). An attempt to determine the habitat of the eurypterids by analyzing their geologic distribution was done by O'Connell (1913, 1916).
Recent works that have helped to refine the stratigraphy are those of Fisher (1960), and Rickard (1962, 1969, 1975). Within the last 15 years more attention has been directed toward the interpretation of environments of deposition. Treesh (1972), Ciurca (1973, 1978, 1982, 1986), Belak (1980), Hamell (1981, 1985, 1986), and Tollerton and Muskatt (1984) have proposed a number of paleoenvironmental models for the Late Silurian rocks of New York.

6: PALEOENVIRONMENTAL ANALYSIS OF THE FIDDLERS GREEN FORMATION (LATE SILURIAN) IN NEW YORK STATE

STOP 1. The Onondaga Limestone
The Onondaga Ls. is the highest unit present and contains a basal sandy layer (Springvale?) just above the unconformity with the Silurian Scajaquada Fm. Most of the Fiddlers Green Fm. is exposed along the highway. Camillus Fm. (Salina Gp.) is exposed north of the railroad overpass.

STOP 2. OWASCO CREEK.
South of the bridge is an exposure of the stromatoporoid biostromal facies of the Cobleskill Fm. (Late Silurian). Downstream are poor exposures of the Fiddlers Green Formation.

STOP 3. THE COBLESKILL AND CHRYSLER FMS.
The Cobleskill and Chrysler Fms. are well displayed at this stop. A cherty facies is present in the Cobleskill Fm. and appears to be limited to the Syracuse area.

STOP 4. SPLIT ROCK QUARRY
There is a complete section of the Olney Fm. in the quarry. Above the Elmwood A is the Onondaga Ls. The uppermost Chrysler Fm. (E. Dev.) is exposed on the quarry floor near the entrance road.

STOP 5. Early Devonian CARBONATES and ANTICLINE.
This Early Devonian carbonate sequence is one of the best exposures of the Manlius Group. in central New York. Facies changes in the Olney Limestone (compared to the type section at Split Rock) are readily apparent. Stromatoporoid biostromes are common and become more important eastward.

STOP 6. TYPE SECTION-FIDDLERS GREEN FM.
Butternut Creek contains fine exposures of this unit. Uppermost Fiddlers Green (mudcrack zone) occurs just above the falls. No Forge Hollow Fm. has been observed here but just up the road (toward the quarry) is a good exposure of the Cobleskill Fm. (celestite facies).

STOP 7. ABANDONED QUARRY-FORGE HOLLOW FM.
The stratigraphic relationships of the Bertie-Cobleskill rocks are clearly shown at this quarry. The Williamsville Fm. has an unique fauna including Paracarcinosoma, Orbiculoidea, and Lingula. Overlying this unit are stromatoporoid beds of the Cobleskill Formation.

7: KIMBERLITES OF THE FINGER LAKES REGION
SUZANNE MAHLBURG KAY
Institute for the Study of the Continents (INSTOC)
Ithaca, New York 14853
BRAYTON P. FOSTER
Consulting Geologist
Lower Covert Road
Trumansburg, New York 14886
Phlogopite-bearing ultramafic dikes in the Finger Lakes region were first reported in the literature by L. Vanuxem in 1837. Although not called kimberlites at the time, these were the first kimberlites described in the world (Dawson 1980). Over the years, numerous papers and theses have been written on their location (Table 1), age, field setting and mineralogy, but many questions regarding the dikes remain unanswered. The dikes have generated interest in each generation of geologists because they are the only manifestations of igneous activity in the Mesozoic in the region; and the timing of their intrusion cannot be easily related to the regional tectonics. These dikes and similar intrusions in Pennsylvania and to the south are the only windows into the lower crust and mantle in the Appalachian basin. The existence of such small ultramafic intrusions from deep within the mantle has caused interest in the mechanism of emplacement of these and similar intrusions. Not incidentally, the designation of the Finger Lakes dikes as kimberlites has generated interest in the possibility of diamonds being found in the region.
LOCATION AND AGE OF THE FINGER LAKES DIKES
Eighty-two dikes and two diatremes have been reported from the Central Finger Lakes region south and west of the city of Syracuse. The greatest concentration of dikes occurs in the glacially cut gorges in and immediately north of the city of Ithaca. Most of the localities are shown in Figure 1 and described in Table 1. Localities to be visited on this trip include Cascadilla Gorge (17), Williams Brook (10), Taughannock Creek (5), Poyer Orchard (8) and Portland Point (20).
The dikes are generally vertical and occur in the prominent north-south joint set in the Devonian sedimentary rocks (see stratigraphic section in introductory part of this guide). Most of the dikes are narrow with widths ranging from several centimeters to about 0.75 meter. Exceptions are dikes near Poyer Orchard and in Cascadilla Creek (localities 8 and 17, Table 1) which are close to a meter wide and the Williams Brook dike (locality 10) which is 3.5 meters wide. Even the thin dikes can extend vertically for great distances. For example, a dike that is only 3-4 cm. wide extends almost 100 meters up the gorge wall at Taughannock Falls (Table 1, locality 4; Foster 1970). Evidence for multiple injections in the same dike occurs in dikes at the Portland Point Quarry and at Taughannock Creek (Foster 1970).

7: KIMBERLITES OF THE FINGER LAKES REGION

STOP 1 . CASCADILLA GORGE DIKES
PLEASE DO NOT SAMPLE HERE -THIS IS PART OF THE CORNELL PLANTATIONS
Cross the suspension foot bridge towards Collegetown. Before reaching the street, turn right along trail for about 10 meters, and take the steps on the north side of College Avenue to the bottom of the gorge.
The steps are in a break in the gorge wall caused by the differential weathering of the dike that is well exposed at stream level. This dike, which is about a meter wide, strikes parallel to the prominent north-south joint set. Devonian shales on the margins of the dike are intensely fractured for about 1/3 meter on either side of the dike, with the intensity of the fracturing decreasing up to about a meter from the dike. No fresh outcrop is visible on the north side of the creek, but the extension of the dike is easily seen by the intense preferential erosion of the dike material relative to the Devonian shale.
This dike is the most accessible of the wider, fresher dikes in the region and consequently, one of the best studied. A K-Ar whole rock date from Basu et al. (1984) indicates an age of 146 &plusmin;8 m.y. and the dike has a normal magnetic polarity with a pole position consistent with a lower Cretaceous age (DeJournett 1970). In thin section, the dike consists of 31% groundmass which includes apatite, calcite, serpentine and other secondary minerals, 38% rounded serpentine after olivine and pyroxene, 21% phlogopite, 4% opaques, 6% perovskite, and occasional xenocrysts of clinopyroxene, orthopyroxene, garnet (pyrope) and spinel (Foster 1970 and Snedden 1983). Minor quantities of amphibole are attached to mafic mineral fragments. A small garnet pyroxenite xenolith was found in this dike by Schulze et al. (1978) and other upper mantle and crustal fragments have been discussed by Kay et al. (1983). Xenocrysts of Mg-rich diopsides, Mg-rich phlogopites and Mg-spinel in the dike suggest that Grenville age granulite facies carbonate rocks occur in the subsurface at this locality.
Five other dikes have been reported from this locality and finding them illustrates the problems in locating new dikes and relocating dikes already described in the literature. Proceeding downstream, the first reported dike is reported to be 8 cm. wide and occurs 10 meters east of the dike described above just to the east of the bridge. The dike apparently occurs in the deeply eroded notch on the north side of the creek. (Note on following localities -In August 1986, the trail below the bridge was officially closed. Proceed at your own risk). The next 2 dikes occur about 1/3 meter apart and are located on the bench between the first and second falls about 40 meters west of the bridge. They vary in width from 5-25 cm. and occur parallel to the N-S joints in the stream bottom on the north side of the creek. After a heavy rain, they are visible striking up the deeply eroded notch on the south side of the creek. Two other dikes, spaced about 0.4 meters apart with widths up to 25 cm., occur below the second falls before reaching the buildings visible on the cliff above (directly below the Eddy gate which is not visible from the stream). These dikes had not been visible in recent years, but were exposed again after a particularly heavy rainstorm in mid-August 1986. They can be seen striking up the heavily eroded notches on either side of the gorge. The eastern dike is heavily altered while the western dike is relatively fresh. They are too deeply eroded to be seen in the stream bottom.

STOP 2. WILLIAMS BROOK DIKE
Hike about 60 meters up Williams Brook from parking area. Dike is well exposed on the north side of the creek.
The Williams Brook dike, which is a dense black rock with abundant visible phlogopite, is the widest of the dikes (about 3.7 meters across) in the Cayuga Lake region. Within two feet of the contact, calcite veins are common that appear to represent shrinkage cracks formed during cooling and subsequently filled with fibrous calcite. A later generation of veinlets perpendicular to the contact cuts, and offsets the earlier veins by up to 1.5 cm. Although no visible thermal alteration is present on the margins of the dike, DeJournett (1970) reports a magnetic alteration zone up to 2 feet wide. He also reports that the dike is normally polarized and that the pole position is consistent with a Lower Cretaceous age for the dike. An age of 139 &plusmin;7 m.y. is indicated by a whole rock K-Ar date (Basu et al. 1984).
The Williams Brook dike is petrographically distinct from other dikes visited on this field trip. Modally, it consists of 35% serpentine after olivine, 25% phlogopite, 8% magnetite, 13% perovskite and 19% groundmass composed of calcite, serpentine, apatite and other secondary minerals (Foster 1970). The phlogopite exhibits a poikilitic texture and is more abundant than in the other dikes. Calcite (<10% modally) is less abundant than in most other dikes (10-73%). No xenocrysts of garnet, spinel or pyroxenes have been observed in the dike.

Paleontological Research Institute on right.

STOP 3. TAUGHANNOCK CREEK DIKES
THIS IS A NEW YORK STATE PARK. NO HAMMERS OR COLLECTING ALLOWED.
Walk to stream bed. Refer to Figure 2.
Ten dikes crop out in Taughannock Creek (Figure 2) over a distance of 0.8 kilometer upstream from the road bridge above the high falls. You are even with dikes 2-5 at the parking area. These dikes outcrop best on the ledge on the south side of the creek. Dikes 4 and 5 are 1.2 meters apart. Dike 3 is about 16 meters east of dike 4 and dike 2 is about 3.5 meters east of dike 3. Dikes 6-8 crop out above the stream in a closely spaced cluster, a short distance to the west of the parking area. Dikes 9-10 are upstream about 30 meters east of a stress-release "pop-up" in the Devonian shale in the middle of the stream. Dike 10 is exposed under a tree on the south bank of the river. The outcrop has been considerably reduced by sampling in recent years. Dike 9 is very difficult to find.
The control of the dike orientation by the prominent N-S joints is particularly well exhibited at this locality. In addition, the closely spaced joints that typically occur in the country rocks parallel to the dikes are well developed along several of the dikes. Dikes 1, 4 and 10 extend across the exposed bedrock outcrop while the other dikes pinch out rapidly in both directions. The occurrence of the dikes in clusters (1; 2-3; 4-5; 6-8; and 9-10) suggests branching by one or more feeder dikes near the present surface. A large shale xenolith in the center of dike 8 suggests how this divergence occurs. The composite width of each dike group appears to remain constant across the outcrop width as illustrated by the northward thickening of dike 4 and the southward thinning of dike 5. Dike 10 shows (or did show) evidence for three possible injection episodes in which material was deposited along the contacts and not completely removed by later events.
Petrographic differences occur among the dikes at this locality. The general mineralogy of all the dikes is similar to that in the Cascadilla Gorge dike (Stop 1), but the modal percentages are variable (Foster 1970). Dike number 10 is the widest and freshest dike at this locality and has 37% serpentine, 7% phlogopite, 5% magnetite and perovskite and 51% ground.mass (Foster 1970). Most of the other dikes show considerably more alteration. All of the dikes have high concentrations of calcite in the ground mass (dike 1 -35% calcite, 2 -25%, 4 -36%, 7 -23%, 10 -23%) (Foster 1970).
The xenocryst assemblage in the Taughannock dikes consists of pyrope garnet, green chrome diopside, augite and spinel. Dikes 6, 7 and 8 are anomalous in that they are very calcite rich (up to 30%), yet contain abundant xenocrysts of unaltered olivine, Cr-diopside, augite and garnets (Foster 1970). Garnet is particularly abundant in dike 8. Small eclogite xenoliths have been reported by Basu et al (1985) and Taylor and Hunter (1982). Mineral compositions for xenocrysts in these dikes are reported by Kay et al. (1983). Martens (1924) reports finding graphite in dike 10.
DeJournett (1970) reports that dike number 10 has a normal magnetic polarity with a pole position consistent with a lower Cretaceous age. Basu et al. (1984) obtained a whole rock K-Ar age of 121 &plusmin;23 m.y on one of the dikes from this locality.

STOP 4. POYER ORCHARD DIATREME
Walk about 500 meters along the orchard road to the old part of the orchard. Head north north-east to the ravine about 50 meters beyond the orchard boundary. The diatreme is exposed in the bottom of the ravine where it is particularly wide due to the preferential erosion of the diatreme relative to the surrounding shales. Remnants of the sluicing operation are visible near the diatreme.
The amount of visible exposure depends on the intensity of recent storms. In the original report on the locality, Barnett (1905) was uncertain whether two dikes (7.6 and 4.0 meters across respectively) or a single intrusion (46 meters across) occurred. After an exceptionally large storm in the late thirties, Filmer (1939) described the intrusion as a breccia pipe or a swelling in a single large dike that extended 58 meters in an east-west direction and 24 meters in a north-south direction.
In subsequent literature (i.e. Foster 1970), the outcrop has been called a diatreme. The petrology of the unit is consistent with its classification as a tuff breccia of the kimberlite diatreme facies (see Dawson 1980). The outcrop is composed of extremely abundant xenolithic fragments surrounded by a very altered groundmass consisting of hydrothermal-type minerals. The groundmass has not been studied in detail. The outcrop is cut by several irregular tuffaceous dikes about 15 cm. across. An x-ray diffraction scan of the tuffaceous dike material by Foster (1970) indicated the presence of microcrystalline calcite and phlogopite.
Most of the xenoliths are angular pieces of sedimentary rock derived from the enclosing Devonian shale. These inclusions average about 5 cms. in diameter, but some as large as a half meter in diameter have been observed (Foster 1970). Fossils in inclusions reported by Filmer (1939) have not been studied. Other sedimentary inclusions are rounded sandstone and quartz pebbles. Rounded pieces of kimberlite similar to those found in nearby localities also occur as inclusions. Several syenite xenoliths, approximately 12-15 cm. across, were found during the sluicing operation (Wells, 1977, personal communication) and similar smaller xenoliths were analyzed by Snedden (1983). A fragment containing actinolite, chlorite, potassium feldspar and sphene reported by Kay et al. (1983) suggests that lower grade Precambrian rocks overlie the granulite facies in the basement in this locality. The heavy mineral fraction of the diatreme contains relatively abundant garnet, spinel and pyroxene xenocrysts (Foster 1970, Snedden 1983, Kay et al. 1983).
A magnetic anomaly map of the locality (Figure 3) produced by Angerani and Hangus (1978) as a term project in a geophysical methods course at Cornell gives additional information on the extent of the body. The map shows that the body is elongate north-south and continuous along the length of the survey (150 meters). The most intense magnetic anomaly occurs just to the north of the stream and a second smaller anomaly occurs parallel to the main anomaly about 20 m. to the east. Angerani and Hangus modeled the anomalies as vertical dikes and suggested that the width of the main dike varies from 1.4-4.0 meters and that its top is buried from 1.6 to 5.1 meters below the surface. In the model, the maximum depth and widest part of the intrusion occur at the maximum anomaly. Their model predicts the second dike is 4.1 meters wide and 11.1 meters deep.
The magnetic model does not take into account that the stream exposure is in the diatreme facies. Combining the magnetic information with the petrography of the outcrop suggests that the diatreme represents a wide spot in a dike which along strike is similar to other larger dikes in the region (i.e. those in the same ravine, see localities 8b and 8e in Table 1). Although the magnetic data may indicate that two dikes occur, the discontinuous nature of the smaller anomaly is consistent with the magnetic pattern indicating the irregular configuration of the diatreme. The magnetic modeling in the narrow part of the anomaly north of the stream (Figure 3) is consistent with a dike 1.4 meters wide, striking N5W (Angerani and Hangus 1978).
As reviewed by Dawson (1980), diatreme facies kimberlites are, in general, interpreted to result from explosions resulting from the rapid cooling by groundwater of fluidized mixtures rich in exsolved high pressure gas. This suggests that the Poyer Orchard diatreme formed as part of the dike encountered groundwater and an explosion occurred. This interpretation is supported by the abundance of angular fragments from the surrounding country rock. The tuffaceous dikes would then result from the explosion. If the diatreme formed by this mechanism, the present erosion surface at Poyer Orchard was within the groundwater table in the lower Cretaceous.

STOP 5. PORTLAND POINT QUARRY
THIS IS PRIVATE PROPERTY. YOU MUST OBTAIN PERMISSION TO ENTER. Collecting is allowed. Fossil collecting is also good in the quarry (see guides for other trips). The quarry is complex and constantly changing. Ask quarry personnel for best places to view kimberlite dikes.
Walk south 1 kilometer along the main quarry road to the east-west trending southern quarry wall (parallel to the north side of Falls Gulf Creek). In August 1986, this was the southern part of the main pit. Quarrying was complete and the region was being backfilled. The slag heaps near this area of the pit had blocks of kimberlites.
Two segments of north-south striking dike are exposed in the east-west trending wall of the quarry, above and below the nearly horizontal trace of a thrust fault which strikes east-west and has a shallow dip to the south (third dimension of fault is exposed in adjacent north-south trending quarry wall). The fault, which is marked by a slickensided surface above a brecciated zone, is associated with the crest of the Firtree anticline, a late Paleozoic Alleghenian fold (i.e. Engelder and Geiser 1979). Slickensides dipping 20° to the south can be seen on the east facing dike surface adjacent to the country rock indicating some post emplacement differential slip between the dike and the wall rock.
As discussed earlier, the dike segments have an early Cretaceous age (Zartman et al. 1967, DeJournett 1970, Basu et al. 1984). They are not offset by the fault, which apparently constituted a discontinuity in the north-south joint system across which the dike was diverted. The upper dike segment, which is about 1.5 meters to the east of the lower segment, is uniformly about 20 cm. wide and terminates in the fault zone. The lower segment tapers from a maximum width of about 20 cm.. to about 12 cm.. at the fault. As it passes through the rubble zone below the fault, the dike bends and shows at least one minor offset of about 20 cm. to the east. The lower dike segment also tapers to about 20 cm. in width near the bottom of the exposure that outcropped in August.
Another exposure in the quarry where dike segments are bounded by a fault zone was described by Sheldon (1927) and may have been along strike of the present exposure. On the basis of the geometry of pinching and swelling of dikes in that exposure, Sheldon argued that dike intrusion was contemporaneous with the latest stages of faulting. The relationship of the dike segments to the fault zone in the modern exposure, and the observation that pinching and swelling occur in discontinuous dikes in other localities where evidence of faulting is not observed (Stop 3 and below), strongly suggest that the dikes observed by Sheldon were also not offset by the fault.
The exposed dikes may be along strike of the locality where DeJournett (letter to A. Bloom 1971) mapped dikes extending about 120 meters across the quarry floor in 1970-71. He indicated that these dikes showed normal magnetic polarity in the interiors and reverse magnetic polarity on the exteriors. He also stated that the dikes showed textural evidence consistent with two episodes of intrusion and that these textures correlated with the magnetically distinct zones. His map clearly shows that the dikes pinch and swell and are discontinuous. These features were not visible in 1986.
Leave the main pit and head north and east along road to the older inactive part of the quarry. The road to the bottom of the pit of interest is blocked by a small slag heap. This pit is in the eastern part of the quarry, southeast and across a large slag heap from the quarry lake that is visible from the hill above the pit (see Ludlowville 7.5 minute topographic map). In August 1986, this pit had much less mud and grass on the floor than surrounding pits.
In this pit, a N-S dike about 5-7 cm. wide can be followed across the quarry floor. The exposure has deteriorated considerably in recent years due to sedimentation on the quarry floor and the weathering of the dike. Blocks of the kimberlite that have sedimentary xenoliths and show textural inhomogeneities can be found in the surrounding slag heaps, particularly along the northwest wall of the pit. Some of these blocks show possible evidence for multiple intrusion.

8: ICE READVANCE IN THE VALLEY OF FIVEMILE CREEK, STEUBEN COUNTY, NEW YORK, AND THE EFFECT OF THE RESULTING DEPOSITS ON POSTGLACIAL STREAMFLOW
ALLAN D. RANDALL
Albany, New York, 12201
Fivemile Creek rises near Jubertown swamp in the town of Jerusalem, Yates County, New York and flows southwestward to join the Cohocton River near Kanona in the town of Bath, Steuben County (fig. 1). Stratified drift deposited during the main Wisconsin deglaciation of Fivemile Creek valley is generally mantled by till or related diamicts attributed to a readvance of the ice. Younger deposits, laid down during and after the decay of the readvanced ice, include large areas of clay-silt rhythmites and of organic rich muck. Most broad valleys of the Susquehanna River basin are floored predominantly by sand and gravel, and the presence of till, clayey silt, and muck at land surface over large areas of the floor of Fivemile Creek valley is chiefly responsible for the remarkably small discharge per square mile from this watershed during periods of low flow.
This article can be read as an example of how knowledge of geology can help us understand surface-water hydrology, or of how knowledge of stream flow can require reinterpretation of geology. It was prepared as an offshoot of studies of the interaction of aquifers and streams in the glaciated Northeastern States under the Regional Aquifer Systems Analysis program of the U.S. Geological Survey. It includes an interpretation of surficial geology and deglacial history of Fivemile Creek valley, a summary of evidence supporting that interpretation, and an explanation of the influence of surficial geology on flow of Fivemile Creek and other streams in the Susquehanna River basin. It concludes with an outline of a field excursion designed not only to display the Pleistocene stratigraphy but also to show how streamflow data, depth to water, well records, auger holes, and soils maps can be used to supplement examination of natural and artificial exposures in deciphering surficial geology. The study did not include test drilling, geophysics, regional correlations, nor determination of till fabric or provenance.
Stops 1 and 2 show conditions in a typical valley of the Susquehanna River basin, to be contrasted later with conditions in Fivemile Creek basin. Stops 3-5 present evidence for till overlying stratified drift. Stop 6 and nearby hesitation stops overlook the divide at the head of Fivemile Creek. Stops 7-9 show diamict and other deposits in preglacial lakes during and after the inferred ice readvance. Stop 10 considers the hydrologic implications. The road log begins at the entrance to Buttermilk Falls Park along Route 13 just south of Ithaca.

8: ICE READVANCE IN THE VALLEY OF FIVEMILE CREEK, STEUBEN COUNTY, NEW YORK, AND THE EFFECT OF THE RESULTING DEPOSITS ON POSTGLACIAL STREAMFLOW

The route follows the valley of Cayuga Inlet
The route follows the valley of Cayuga Inlet, a trough greatly overdeepened by glacial erosion. Bedrock is more than 400 ft below the valley floor and is below sea level.

View to left of continuation of the Cayuga Inlet trough.

Cayuga Inlet trough
Views to left across Cayuga Inlet trough, next 0.5 mile.

West Branch Cayuga Inlet
Entering valley of West Branch Cayuga Inlet, a tributary valley also enlarged by glacial erosion, but not as deeply.

Views left across valley next 1.1 mile.

Hummocky valley fill
Near crest of hill: view to left of hummocky valley fill; note absence of stream channel.

STOP 1. VIEW OF THROUGH VALLEY.
To the right, valley floor is relatively smooth, slopes gently southwest, and is underlain by outwash gravel. To the left, valley floor is hummocky, slopes irregularly northeast, and is underlain by the same outwash gravel, deposited in part over buried ice that did not melt until after the flow of meltwater and sediment cased. Most large streams in the Susquehanna River basin head in one or more through valleys like this: broad valleys that transect the drainage divide and served as a channel for ice during glaciation and for meltwater during deglaciation. Alluvial fans of small tributaries are visible at the base of the far valley wall; these streams flow southwest on the valley floor but lose water by seepage and are usually dry. The trees that form a line across the valley floor to the southwest border Carter Creek, a larger tributary that also loses water by seepage; the ground-water mound thus created near Carter Creek constitutes the groundwater divide in this valley.

Cross Carter Creek.
For next 3 miles the route descends a valley train of outwash augmented by alluvial fans of tributaries.

Cross Pony Hollow Creek.

Hendershot Gulf
Cross dry channel leading from Hendershot Gulf, a meltwater spillway and incipient through valley.

STOP 2: COARSE OUTWASH.
The lower terraces in most broad valleys in the Susquehanna River basin are underlain by out-wash gravel. The gravel exposed here is coarser and richer in clasts of local shale bedrock than most outwash, because it lies immediately down-gradient from a remarkable 4-mile long spillway cut in bedrock, from which many of the clasts were doubtless eroded.

Enter Fivemile Creek valley.
For the next 0.8 mile, ice-contact stratified drift mantles the lower valley walls (both sides), up to more than 200 feet above road level.

Cross Fivemile Creek.

Road is cut through "valley choker" moraine
Test borings (Randall, 1972) suggest that till constitutes more than 50 percent of its mass; road borders north edge for the next mile. Fivemile Creek is briefly incised in bedrock at east side of valley.

Wheeler
Route 53 is on outwash, overlapped by alluvial fans from the west; views to the left of fans next 0.3 mile.

Avoca-Wheeler Rd on left.
For next 1.3 miles land surface is mostly a pebbly clay diamict (to be examined at stops 8 and 9)

Large barn on left; shallow pond on right.
Near pond, a well was reported to penetrate "hardpan" (till), then obtain a large yield from gravel at a depth of 40 feet

Wetland to right of road.

STOP 3: TILL-MANTLED STRATIFIED DRIFT.
Topography, as shown on topographic map and as visible from this point, is suggestive of a kame terrace; a moderately level surface, hummocky in detail, 40 feet above the floodplain. At the trailer to the north, a well is finished in gravel at a depth of 40 feet, after another well was abandoned at about 130 feet after penetrating many feet of fine sand. However, roadcuts 400 to 800 feet east and 400 feet north of the intersection reveal till.

Cross Fivemile Creek, bear right.

STOP 4: TILL-MANTLED STRATIFIED DRIFT.
Till is exposed in a small excavation here. Wells in the two small buildings on the valley floor immediately to the southeast supply 150,000 gallons per day to the creamery; the village of Prattsburg obtains most of its water from a well 250 feet further south. Drillers' logs of these wells and nearby test holes differ in detail but all indicate that silty or clayey gravels and stony clay (or hardpan) predominate. The well nearest the creek reportedly penetrated:
0-13 feet | | soft clay
13-32 feet | | boulders, clay hardpan
32-66 feet | | mostly gravel, silty, yields some water
66-72 feet | | gravel, yields more water
72-89 feet | | hardpan.
Walk 300 feet downstream along Fivemile Creek to view exposure of post-till gravel on opposite bank. Return to main road •

Pass Narcissa Prentiss house.
Narcissa Prentiss Whitman
1808 – 1847
Narcissa Prentiss was born in Prattsburgh on March 14, 1808. Her father, Stephen Prentiss, came to Prattsburgh in 1805. Although the house he built for his family is quite small, Stephen and his wife Clarissa raised 9 children there. Narcissa attended Franklin Academy and became a schoolteacher – teaching in Prattsburgh and Bath, and she was active in church affairs and dreamed of becoming a missionary. She married Dr. Marcus Whitman in 1836 and together they journeyed 3,000 miles through country largely unknown to white men, ending their journey in the Oregon country claimed jointly by the United States and Great Britain. She was one of the first 2 white women to cross the Rockies. The Whitmans established a mission among the Cayuse Indians. With Marcus as doctor and Narcissa as school teacher, they tended the physical and spiritual needs of Indians and weary travelers. On November 29, 1847, the Indians massacred everyone at the mission.
Thanks to the Whitman Mission National Historic Site in Walla Walla, Washington and the Narcissa Prentiss House here, the Whitmans’ legacy is alive.

STOP 5: TILL-MANTLED STRATIFIED DRIFT.
Prattsburg Town Highway Dept. garage.
High excavation to east was described in 1984 as follows:
1500-1480 feet altitude | | includes definite till and much problematic diamict (>50% stones in a till-like matrix).
1480-1470 | | Cobble gravel.
1470 | | Layered sands, clean to gummy from interstitial clay, and fine gravels.
1440 | | Till, tough, unoxidized.
1400 | | Base of slope, garage level
Top of cut is 150 feet west of base of steep valley wall.

Note swamp on left at corner.

Note swamps and pond on left and ahead.

View to right across upper Fivemile Creek Valley.
Exposure of till over gravel in woods ahead, 1000 ft east of road. Flat valley floor is underlain by peat.

View to right across Jubertown Swamp
View to right across Jubertown Swamp (head of Fivemile Creek). Skyline beyond swamp is not marked by deeply incised saddle or through valley.

Crest of hill.
Views to right (northwest) and to the rear (north) of gentle saddles on basin divide.

STOP 6: VIEW OF BASIN DIVIDE
This saddle, the lowest on the Fivemile Creek divide, shows no incision or deposition due to meltwater flow. The slope ahead (east) descends to Keuka Lake, 730 feet below this saddle. The deeper valley presumably captured most ice and meltwater flow when the ice surface was above this saddle, and certainly when it was below.

Swampy depression beside road on right.

Alluvial fan of a brook.
For next 0.2 mile, land surface is underlain by 5 feet of flatstone gravel, an alluvial fan of a brook.

Till exposed at base of knoll on right
Till exposed at base of knoll on right, overlain by 10 feet of silty gravel, fine sand, and sandy gravel, presumably late-glacial inwash.

Cross Fivemile Creek.
Floodplain downstream from here is underlain by silt, clay, peat, and organic-rich muck that extends at least 5 to 15 feet below stream grade.

View of "Prattsburg Muck".
This large ice-block depression, underlain by many feet of peat, is drained by buried tiles to perimeter ditches, which drain (or, if necessary, are pumped) into Mud Lake and thence into Fivemile Creek. Crops of lettuce and onions are grown here. The muckland occupies most of a broad tributary valley that heads at a gentle saddle overlooking the Keuka Lake-Hammondsport valley, like the saddle at stop 6.

Road crosses the BS outwash delta.
Surficial sediment is pebbly medium to coarse sand. A well drilled in 1949 near the buildings south of the junction was abandoned at a depth of 320 feet, after penetrating mostly "quicksand" (silt to very fine sand) and clay.

A well drilled here in 1983
A well drilled here in 1983 was abandoned at 70 feet depth after penetrating only clay and silt.

STOP 7. LAKE-BOTTOM DEPOSITS.
Auger holes 270 and 820 feet west of road penetrated layered silt and clay, capped (near the road) by very fine sand.

Pond and swamps on left.

STOP 8: PEBBLY CLAY DIAMICT.
Walk along far side of the field west of the road to a small exposure in the bluff above Fivemile Creek.
This exposure is plotted on figure 4. The sketch shows its appearance in 1983 .

Outlet of former spillway
View left, at turn, of outlet of former spillway from Mitchellsville.

Wells nearby are finished in gravel beneath surficial pebbly clay.

STOP 9: PEBBLY CLAY DIAMICT.
This exposure is plotted in figure 4. It was described in 1986 as follows
0-12 ft | Clay or silty clay, containing 1 to rarely 5 percent rounded to sharply angular pebbles and coarse sand; no regular bedding recognized, but a few deformed streaks or blebs of coarse silt observed; oxidized.
12-15 ft | Pebble-cobble gravel, rounded, a few exotics, generally very silty, appears to grade northward into very pebbly clay.
15-20 ft | (exposed)
20-30 ft | (augered) Sparsely pebbly clay, like that above but unoxidized, plastic.
30 ft | Gravel; could not penetrate. Property owner reports accelerated recession of this bluff 1984-86 since channel of tributary entering from the west was excavated for flood control, which owner believes has caused deflection of the flow of Fivemile Creek against this bank.

STOP 10: FIVEMILE CREEK GAGING STATION.
Records of stage and flow have been collected here since February 1937. The operation of the station will be explained, and the influence of surficial geology on the minimum flow measured here will be discussed.

9: GEOMORPHOLOGY OF THE CAYUGA LAKE BASIN
ARTHUR L. BLOOM
Institute for the Study of the Continents
Ithaca NY 14853
The Finger Lakes Region of Central New York is justly famous for two aspects of its geology: the Devonian stratigraphy and the Quaternary geomorphology. Not as well appreciated is the fact that the Quaternary landscape is the result of 360 million years of post-Devonian erosional history, for which no stratigraphic record is available in the region. An enormous unconformity everywhere separates glacial drift of late, or at the oldest, middle Pleistocene age, from the underlying lithified and mildly deformed Devonian marine strata. Volumes of sediment on the North Atlantic continental shelf and rise imply at least 2 km of regional denudation in the Cenozoic Era (Mathews, 1975). The remaining Paleozoic section in the Finger Lakes region is little more than 2 km thick, so at least half of the depositional section is gone. With a regional southward dip of about 1 per cent, 2 km of vertical denudation involved 200 km of homoclinal shifting of the present north-facing escarpments. The landscape viewed from the hill tops around Ithaca has a grand story to tell, when we can learn to listen.
The key to the geomorphology of the Finger Lakes Region lies in the geometry of deposition, deformation, and denudation. The Upper Devonian sedimentary facies were deposited in an epicontinental sea with a rising source area to the east; facies boundaries trend northeast to southwest, with Catskill facies alluvial-plain redbeds to the east, nearshore marine sandstones next to the west, and these grading westward into shales. Post-depositional regional deformation gently folded the Devonian rocks along fold axes trending N70°E, significantly shortened the sedimentary pile in a N-S direction (Engelder, this volume, and references therein), and regionally tilted the pile southward about one-half degree (1 per cent, 10 m/km, or 50 ft/mi).

9: GEOMORPHOLOGY OF THE CAYUGA LAKE BASIN

Ascending a series of hanging deltas through the campus.

STOP 1. Lake Ithaca beach ridges near the Equine Research Laboratory.
In the course of making a detailed soils map of the Cornell campus area at a scale of 6.7 inches to 1 mile (1:9500), Professor M.G. Cline and his students defined several areas with narrow ridges of well-sorted pebble gravel that are uphill from typical lacustrine silt-clay units of glacial lake Ithaca, and are downhill from non-lacustrine stony till soils (Cline and Bloom, 1965). The site along Bluegrass Road (Fig. 3) is typical. The pebbly soils are well drained, fertile, and warm, and have been allocated to small garden plots for Cornell staff and students. Downslope in the Cornell fields is a poorly drained belt of wet, cold soils, and across Bluegrass Road to the east is typical thin upland till, probably only a meter or less deep to bedrock. The gravel ridge was interpreted as a beach ridge of glacial Lake Ithaca, correlative with the 980-ft overflow south of Brooktondale at Belle School Road (Stop 9). A similar setting and soils sequence crosses Ellis Hollow Road and Game Farm Road along the base of Snyder Hill.
The beach ridge here is at an elevation of about 1020 ft; the similar ones in Ellis Hollow are about 1000 ft above sea level. The two beach ridge localities are 8 miles and 6 miles north of the 980-foot overflow, so the present gradient of the Lake Ithaca shoreline rises northward at 3 to 5 ft/mile. Possible causes include: (1) downcutting of the outlet during the life of glacial Lake Ithaca; (2) hydraulic gradient southward through the outlet (unlikely for a large, deep lake); (3) gravitational attraction of the water body northward toward the still extant ice mass; or (4) postglacial isostatic recovery increasing to the north. The tilt was aggressively debated by earlier geologists. Professor O.D. von Engeln gently referred to "a cult among geologists interested in the high levels of preglacial lakes which adheres to the concept that a postglacial northward uplift of the land made the original shore lines of the lakes rise toward the north" (von Engeln, 1961, p. 93). He went on to argue correctly that the correlation of delta tops from one tributary valley to another is much too indefinite to justify calculating a tilt. Perhaps he would soften his view if he could see the evidence we see today (or perhaps he would not!).

Note subdued ground moraine topography.

STOP 2. Top of the Varna high bank.
Fall Creek valley at this cross section is filled by a variety of Pleistocene sediments to be viewed in better perspective from stop 3. During the detailed soil mapping of the Cornell properties, Prof. Cline and his students noted the silt enrichment of the soil profiles in the fields north of this locality, and tentatively attributed it to an influx of eolian silt and sand in late glacial time. To their credit, the soils mappers noted that their eolian hypothesis did not fit the observation that the silt enrichment was found only below the 1060-ft contour. As long ago as 1934, H.L. Fairchild had named a shallow ice marginal lake called Freeville-Dryden Lake in the Fall Creek valley, which overflowed south around the west end of Mt. Pleasant into Cascadilla Lake and through the southeast end of Ellis Hollow (along Thomas Road, southeast corner of the Ithaca East topographic map.) The overflow is just above 1060 ft (Fairchild's contour maps were in error), so Freeville-Dryden Lake must have been quite shallow and muddy, and it probably provided a minimal gradient for the ancestral Fall Creek when an ice wall to the west finally calved and drained Freeville-Dryden Lake down from 1060 ft into Lake Ithaca (in this region, at or below 1020 ft). The lowering of the local base level probably initiated a headward-migrating nick point across the exposed floor of Freeville-Dryden Lake and initiated the postglacial evolution of Fall Creek valley.

Cross Fall Creek.
Bridge and bank repairs postdate 1972 and 1981 floods.

STOP 3. Base of the Varna high bank.
At base of the "Varna Moraine" (actually an alluvial terrace scarp). Walk north through the woods to the bank of Fall Creek.
The high banks along Fall Creek north of Varna show the glacial stratigraphy. The lower half of the undercut bank over 100 feet in height exposes poorly sorted, crudely stratified sand and gravel. About 90 percent of the pebbles in the gravel are sandstone and shale of local derivation, and about 10 percent are limestone and crystalline erratics from the north. The sand, silt and clay matrix of the gravel is strongly calcareous. This stratified sand and gravel records the damming of lower Fall Creek by ice spreading eastward out of the Cayuga trough, while the headwaters of the creek were still ice-free.
Overlying the sand and gravel is about 40 feet of compact till that records the advance of ice up or across Fall Creek valley. Only about 70 percent of the till pebbles are of local origin, and most of the remaining 30 percent are limestone or dolomite. The tough, blue-gray matrix of the till is strongly calcareous. A thin layer of lacustrine sediments caps the oxidized upper part of the till.
As the succession of preglacial lakes in the Cayuga trough gradually fell to the level of present Cayuga Lake, Fall Creek has energetically re-excavated its interglacial valley. The thin cap of silt from Freeville-Dryden Lake was cut through while Lake Ithaca still drained through Willseyville Creek. Subsequently, Fall Creek established its postglacial course down the side of the Cayuga trough, soon to become superposed across buried rock spurs to give the succession of gorges and falls along the north edge of the campus. North of Varna, Fall Creek has not yet exposed its former rock floor.
Most of the cross-sectional area of the Fall Creek valley fill seems to be stratified sand and gravel. Roughly, the cross-section area of the modern valley on this transect is one-half as wide and about one-half as deep as the interglacial valley. Further downcutting has been inhibited by superposition on buried rock farther downstream (stop 5), but lateral migration has been extensive. The "Varna moraine" of Tarr (1909b, p. 151) and von Engeln after him, is only a cut bank of the valley fill. The "proximal" face of the "moraine" exposes a layered stratigraphy similar to that in the high bank.
In Fall Creek valley near Beebe Lake, and at several places along Six-Mile Creek, are exposures of non-calcareous, clay rich diamictons in which the few remaining granite gneiss pebbles and cobbles are totally "rotten". It seems clear that most of the valley cutting in bedrock around Ithaca predates at least two glaciations, although most of the earlier drift filling was removed and replaced by calcareous drift of probable Wisconsin age. An interesting applied aspect of the layered valley fill is that any dams across Fall Creek or other rivers in the Cayuga basin would involve a high risk of leaking through the coarse alluvial members of the glacial drift in the ancestral valleys.

Flood of 1981 exposed bedrock in channel, here.

STOP 4. Water tanks
From this stop at the 970 ft contour, the continued late-glacial and postglacial evolution of Fall Creek valley is easily viewed. The water tanks are on the highest point of the campus, below the water level on a fan-delta that Fall Creek built into glacial Lake Ithaca. A soil pit in the vicinity show a sandy loam, probably subaqueous. Other slightly higher parts of the surface to the east may be underlain by subaerial topset beds. Broad, shallow channels radiate down the delta slope from the apex.
Far on the southwestern skyline is a notch which is said to have puzzled Professor R.S. Tarr and others since. Is it a wind gap recording the ancestral course of Fall Creek to the southwest, prior to capture by a north-draining escarpment stream? In part it is an optical illusion formed by a low ridge profiled against adjacent higher hills, but the location is intriguing.
Northeast of the water tanks is the Newman Arboretum, being developed as a major regional collection of native trees and shrubs. The Arboretum crosses the slopes of an abandoned meander of Fall Creek with a floor at about 900 feet, the regional level of glacial Lake Newberry. Lake Newberry drained past the south end of Seneca Lake toward Elmira, and was a very extensive ice-marginal lake across central New York. A smaller meander terrace 30 ft lower, in the shrub collection and test garden area, still shows an abandoned meander channel at its outer bend. This lower meander scar must be very close to a bedrock floor.

View east of Mt. Pleasant cuesta.

View southwest from Newman overlook
Wind gap of ancestral Fall Creek?

STOP 5. Flat Rock
This section of Fall Creek, slightly eroded into shale and siltstone, is the local and temporary base level for upper Fall Creek valley. No bedrock is now exposed in the stream bed until north of Maclean, a distance of at least 10 miles. In re-excavating its interglacial valley Fall Creek here encountered a bedrock spur and became superposed across it, thus greatly deterring further downcutting and permitting the broad lateral swings of the meander belt upstream. This popular local swimming hole was almost obliterated by a nasty overnight rainstorm in late October 1981. Some of the large slabs of siltstone in the stream bed were observed to be flipping edge-over-edge during the flood, which reached almost to road level.
Several hundred meters downstream, Fall Creek drops over a low waterfall and loses its bedrock floor, which appears again upstream of the Forest Home Drive bridge at the Wildflower Garden. An ancient buried channel of Fall Creek apparently crosses beneath the modern channel in the interval of no rock exposures.
to erode such a channel, but if it collected meltwater from an ice margin that briefly rested against the north face of Mount Pleasant in late glacial time, an adequate flow would have been available to cut such a channel in the few centuries that were available for such events.

STOP 6. Mundy Wildflower Garden, Cornell Plantations.
The Mundy Wildflower Garden is established on the floor of Fall Creek valley in another segment of a buried interglacial valley. A short distance downstream from the parking lot, Fall Creek again drops over a low waterfall into a segment a few hundred meters long in which no bedrock is exposed. A low, swampy floodplain in a nearly abandoned meander scar creates a natural habitat for many spring wildflowers. An oxbow swamp is in a well defined channel at the base of the cut bank of the meander scar. The Mundy Wildflower Garden is flooded by extreme high water, but the flora seems to thrive on the aperiodic disturbances .

Around an abandoned meander

STOP 7. The "Forest Home runaround" and Beebe Lake.
A gravel-floored abandoned meander followed by Plantations Road sweeps cleanly around a meander core (or Umlaufberg) on which the Cornell Plantations headquarters building and the rhododendron garden are located. Where Plantations Road and the "runaround" intersect Forest Home Drive along Beebe Lake, no bedrock is exposed. Beebe Lake, like several valley segments immediately upstream, is in a segment of an interglacial valley with a floor below the modern channel of Fall Creek. At the stone bridge over the upstream end of Beebe Lake, the rock walls of the buried valley are exposed, as they also are at the dam. In between is a buried valley of uncertain depth and trend.

View ahead of Mt. Pleasant
Ellis Hollow to the southeast.

Good views to north during ascent.

Small bench on hillside.
Drainage on west side of road is to the south, through the ridge crest.

STOP 8. Mount Pleasant - Observatory, radio towers.
The accordant summits of the Appalachians are a subject long familiar to geomorphologists. In the gentle foreland fold belt of the Ithaca region, structure is not an important factor in summit height. Mount Pleasant is a cuestaform ridge held up by thicker-bedded sandstone and siltstone units in the Upper Devonian section. The plateau to the north, including the subsequent valley of Fall Creek at the base of the north facing escarpment face, ranges in altitude from 1000-1400 feet and is underlain by more erodible shale formations. As the regional topographic slope is to the north and the strata dip south, there is considerable truncation of strata by the upland surfaces (Fridley, 1929, p. 116).
Fridley correlated the upland around Ithaca with the Schooley Peneplain of Pennsylvania, generally found in central New York at an altitude of 1600-1700 feet. He supposed that the somewhat higher hills trending northeast-southwest just south of Ithaca were not controlled by more resistant bedrock, but were along the preglacial divide between the St. Lawrence and Susquehanna drainages. Of course, the concept would imply that headward erosion and capture by a north-flowing stream has progressed as far south as the Ithaca region in preglacial time.
Mount Pleasant and its westward extension known locally as Turkey Hill have been segmented into north-south elongate elliptical ridges by glacial erosion and perhaps meltwater overflow. An especially clear example is a small gully that originates on the north face of Mount Pleasant one mile west of the observatory and drains south into Ellis Hollow across the trend of the ridge crest. No catchment area is available for this gully to erode such a channel, but if it collected meltwater from an ice margin that briefly rested against the north face of Mount Pleasant in late glacial time, an adequate flow would have been available to cut such a channel in the few centuries that were available for such events.

Probable meltwater valley.
Small gully noted at mileage 5.2 passes under road.

Views north and west.

Views southwest of Ithaca College.
Upper row of college buildings are on an ice-marginal overflow channel at 1040 ft. above sea level.

Cross Cascadilla Creek.
Old records described a well 100 feet deep that did not reach bedrock in the valley floor near here (Tarr, 1909a, p. 20).

Quarry of the Finger Lakes Stone Co.
Across the road is the main quarry of the Finger Lakes Stone Co., from which many Cornell University buildings have been faced with "Llenroc".

Good view to left
Good view to left of the 1060 ft. meltwater channel that controlled Freeville-Dryden Lake.

Beaver pond in south-draining floor of meltwater channel.

Radial slope
Road follows radial slope of the large Brooktondale delta/fan.

Delta/fan
Continue ahead up White Church Road onto delta/fan top.

Cross major distributary channel in church camp.
Continue south on kame terrace with colluvial cover from steep hillside.

STOP 9. Belle School Road. Caroline.
The road, here just below 980 feet, forms the divide between the St. Lawrence and Susquehanna drainage. This is the floor of the meltwater channel that was the outlet of glacial Lake Ithaca. To the south, the gradient averages about 10 ft/mi in the 18 miles to the Susquehanna River at Owego. To the north, however, Sixmile Creek drops 600 feet in about 8 miles to Cayuga lake, a gradient of 75 ft/mi. The regional asymmetry of stream gradients is not obvious at Belle School Road, however; swamps drain in both directions from the flat valley floor.
This is probably the valley that was described by R.S. Tarr at the 1905 meeting of the Geological Society of America, when in complimenting Tarr for his perceptive analysis, W.M. Davis proposed that such valleys should be called "through valleys" (Tarr, 1905). Meltwater overflow from proglacial lakes on the north sides of the divides undoubtably helped erode these valleys, since lakes formed both during the advance and retreat of each ice margin that crossed the region.
Most of the highest hills of the region lie within a few miles north or south of the present divide. In the valleys, the acute junction angles of tributaries point north on the north side of the divide and south on the south side. Even though the summits have been rounded and somewhat lowered by ice erosion, the valleys have been widened and lowered, and the former valley side spurs have been trimmed back, both summit heights and tributary junction angles suggest that the present divide is not far from its preglacial position. It is a little surprising that the nearly 10 fold gradient advantage of the north-flowing drainage, that must have been established by mid-Pleistocene time, has not yet begun to shift the divide toward the south from this point. The two tributaries that drain down the west valley wall from Durfee Hill cross the western kame terrace only a few hundred meters apart, and their alluvial plains are separated only by Belle School Road. In any local storm either one could divert and be captured by the other.

STOP 10. (optional). King Road Overlook (1300 feet)
The view north over the Cayuga trough and Ithaca provides an excellent review of the regional geomorphology.

View of Buttermilk Falls.

Note hanging deltas of Coy Glen to right rear.

Abandoned gravel pit in hanging delta.
Excellent hanging-delta morphology uphill for next half mile.

STOP 11. Upper Robert H. Treman State park (Enfield Glen)
The final stop of the trip is in Upper Treman Park, where Enfield Creek has reexcavated an interglacial valley to a point a short distance downhill from the parking lot. There, the postglacial stream became superposed on a bedrock spur and has intrenched along vertical joints to a depth of at least 120 feet above Lucifer Falls and more than 300 feet below the falls, before it submerges in its interglacial valley. The westward retreat of Lucifer Falls has left at least one former tributary hanging on the high south wall of the gorge. The interglacial valley goes through glacial drift on the hillside just north of the gorge entrance, and is marked by a zone of active seepage, soil creep, and tree throw on both its upstream and downstream face.
The large size of the valley below Lucifer Falls suggests that this valley, like the valleys of Taughannock Creek, Fall Creek, Six Mile Creek , and perhaps others, may have been repeatedly excavated and back-filled with glacial drift during the numerous ice ages of the Quaternary Period.

59TH ANNUAL MEETING
NOVEMBER 6-8, 1987
EDITOR
RUSSELL H. WAINES
DEPARTMENT OF GEOLOGICAL SCIENCES
STATE UNIVERSITY OF NEW YORK
COLLEGE AT NEW PALTZ
In rereading the letter of acknowledgements for the 39th Annual New York State Geological Association Guidebook I find little has changed except for the names of most of the participants.
Again I thank the contributors named in the page of contents. Their considerable efforts have provided the 'meat' of the present Guidebook, not only for the moment in this year's trips, but for the anticipated use extending many years into the third millennium.
Additionally, many have labored mightily in other ways to make this year's meeting a success; Diana Parrett, Constantine Manos, Rosario Agostaro and, in many special ways, Robert Cunningham. All of these in one way or another are associated with the Department of Geological Sciences at SUNY, New Paltz and each deserves a special thanks. Many others have given timely assistance; the classes of oceanography and sedimentary petrology at SUNY New Paltz as well as many members of the New Paltz Geological Society who helped with registration, as road guards, and other vital activities and without whose help the work of others would have been much more onerous. Three others at some point in time in this effort have helped in timely fashion; John Johnsen of Vassar College, my wife Dorothy Waines and Martin Rutstein of our Department. Their help is very much appreciated.
Finally, I must mention and thank Todd Leeds of our Department whose excellent oblique aerial photo of the Sky Top Tower at Mohonk Lake graces the Guidebook cover. I should mention also that the tower sits on a fine exposure of a Late Silurian oligomictic orthoconglomerate.
As I wrote twenty years ago "to all these and more, the Guidebook and Annual Meeting owe whatever approbation is deserved."
Russell H. Waines,

A: PAC STRATIGRAPHY OF THE BINNEWATER, RONDOUT AND MANLIUS FORMATIONS OF THE HUDSON VALLEY
E.J.Anderson, P.W.Goodwin, T.R.Buggey, S.P.Osborn, L.J.Saraka and W.M.Goodman TEMPLE UNIVERSITY
The purpose of this trip is to present a demonstration of field application of the PAC hypothesis. Specific objectives include:
1. demonstration of criteria for recognition of PACs in a variety of facies (all STOPS);
2. field checking of stratigraphic columns described in terms of PACs (all STOPS);
3. illustration and discussion of methods of correlation of PACs (all STOPS);
4. demonstration of a major cryptic unconformity at the Manlius-Coeymans boundary (STOPS 1, 2, 3 and 6);
5. demonstration of a minor cryptic unconformity at the PAC 3-5 boundary (STOPS 1, 4 and 6);
6. demonstration of lateral facies change within a PAC (e.g. PAC 9, STOPS 1, 2, 3 and 6);
7. demonstration of episodic onlap over the Ordovician land surface (STOPS 1, 4, 5 AND 6).
THE PAC HYPOTHESIS
The PAC hypothesis (Goodwin and Anderson, 1985) is a comprehensive stratigraphic model which states that most stratigraphic accumulation occurs episodically as thin (less than 5 meters thick), generally shallowing-upward cycles characterized by internal vertical and lateral facies continuity (i.e. conjunct facies relationships). Cycle boundaries, defined by abrupt facies change to disjunct facies, are created by what stratigraphically appear to be geologically instantaneous relative base-level rises. The PAC motif (punctuation and aggradation) is independent of specific facies and therefore a single PAC may be peritidal at one locality and totally subtidal at another locality. The events which produce PAC boundaries are thought to be sea-level fluctuations. Because such events are allogenic, PAC boundaries are essentially synchronous surfaces. PACs are therefore ideal stratigraphic units for intrabasinal correlation and paleogeographic reconstruction.
STRATIGRAPHY OF THE LOWER HELDERBERG GROUP IN THE HUDSON VALLEY
The Binnewater, Rondout and Manlius Formations between Wilbur and Catskill, New York are totally divisible into PACs which can be correlated throughout the study area. The general stratigraphic relationships of these formations and their members were carefully documented by Rickard (1962). Paleoenvironmental interpretations of these rocks were presented by Waines (1976), Harper (1969) and Laporte (1967 and 1969) . An episodic (PAC) stratigraphic interpretation of the formal rock unit boundaries in this area was presented by Anderson, Goodwin and Sobieski (1984) and the cyclic facies architecture and its implications were presented by Osborn (1983), Buggey (1984), Saraka (1984), Goodman (1985) and Goodwin et al. (1986).
In brief summary, the rocks in the study interval represent a diverse set of peritidal and shallow subtidal facies deposited in small-scale allogenic cycles. Correlation and analysis of the distribution of these cycles leads to recognition of a pervasive structure of discontinuities in the lower Helderberg Group. There are not only sedimentologic discontinuities at the bed level but several types of stratigraphic discontinuities (PAC boundaries, small and large scale cryptic unconformities and a traditional angular unconformity).

STOP 1. North Catskill Route 23 exit ramp
.3 miles southwest of New York State Thruway Exit 21.
The Rondout, Manlius, Coeymans and Kalkberg Formations are continuously exposed above an angular unconformity with the Ordovician Normanskill turbidites. The Rondout Formation is made up of 1 PAC and the Manlius contains 10 PACs (PACS 5-14) at this locality. The Rondout PAC has a subtidal fauna in its base and is topped by a massive supratidal dolomite. The first Manlius PAC has been broken up by tectonism. It is overlain by a peritidal PAC (PAC 6) which is probably similar in facies to the tectonized unit. PACs 7, 8, 11, 13 and 14 are entirely subtidal and PACs 9, 10 and 12 are again peritidal cycles.
In addition to discussing criteria for PAC recognition we would like to focus attention on the following observations at this stop. 1. A major correlation point for Manlius PACs is the facies change from cryptalgal laminites to stromatoporoid bearing calcarenite at the base of PAC 11. We will trace this boundary throughout the study area. 2. The stromatoporoid bearing calcarenite at the base of PAC 9 is replaced laterally by thin-bedded shallow-water carbonate turbidites at Stop 2 and gastropod bearing calcisiltite in the Kingston area (Stops 3 and 6). 3. PAC correlations reveal that the Manlius/Coeymans formation boundary is a major cryptic unconformity. To the south at Kingston, PACs 13 and 14 are missing by erosion. To the north and west an additional PAC occurs beneath the unconformity. 4. A minor cryptic unconformity occurs at the boundary between PACs 3 and 5. South of Kingston, PAC 4 is found in this gap. 5. Finally, additional PACs appear below Rondout PAC 3 in the southern localities indicating progressive onlap of the Ordovician land surface.

STOP 2. South Catskill
Route 23A, .2 miles southwest of the intersection with Route 9W.
Manlius PACs 6 to 14 are exposed at this locality. The measured section, both overall and cycle by cycle, is nearly identical in thickness to the North Catskill section observed at the last stop. There are two purposes to this stop. 1. We will demonstrate, PAC by PAC, the degree of similarity between two localities two kilometers apart. This analysis is based on PAC correlations. Marked similarity between the two localities is seen in the thick tidal-flat facies in the upper part of PAC 9 and in PAC 10 and in the major facies change to stromatoporoid bearing calcarenite in PAC 11. In addition, the cryptalgal laminite facies with eroded mudcracks on its upper surface at the top of PAC 12 is the same as at North Catskill A-6 Another primary correlation point is the large facies change from peritidal to subtidal facies at the PAC 5-6 boundary. 2. The second purpose is to demonstrate lateral facies changes within PACs. The boundary between subtidal PACs 7 and 8 is more sharply defined than at the first locality because the calcarenite in PAC 7 is more current washed than at North Catskill. More dramatic lateral facies change within a PAC is illustrated in the base of PAC 9. At this level stromatoporoid bearing calcarenite at North Catskill changes to thin-bedded shallow-water carbonate turbidites.

STOP 3. KINGSTON A
Route 199, .5 miles west of the Kingston- Rhinecliff Bridge.
Manlius PACs 7 to 12 are exposed at this locality. In addition to checking PAC definitions, the following observations can be made at this stop. 1. The primary correlation datum is the major facies change to stromatoporoid bearing calcarenite at the base of PAC 11. Also, as at Catskill, a thin cryptalgal laminite facies occurs at the top of PAC 12. 2. If these correlations are correct, PACs 13 and 14 are missing under the first PAC of the Coeymans Formation indicating a progressive enlargement of the cryptic unconformity seen at Catskill. 3. A major lateral facies change has occurred in the PAC 9-10 interval. These PACs are here represented by subtidal gastropod bearing facies while at Catskill we saw two well developed peritidal cycles at this stratigraphic level.

STOP 4. KINGSTON B
Route 32, .5 miles south of Route 199.
The top of Rondout PAC 2, Rondout PAC 3 and Manlius PACs 5 and 6 are well exposed at this locality. The following observations can be made at this stop. 1. PACs 5 and 6 are peritidal cycles overlain by the subtidal calcarenite facies of PAC 7. This pattern supports the correlation with the like numbered units at Catskill. 2. As at Catskill, PAC 5 overlies the massive Whiteport Dolomite of PAC 3 (Fig. 4). Also, as at Catskill, PAC 4 is still missing in a minor cryptic unconformity (Fig. 2).

STOP 5. Kingston C
Route 32, .5 miles south of Stop 4.
Rondout PACS 2 and 3 (the upper part of PAC 3 covered here is fully exposed at the previous stop) overlie Ordovician turbidites of the Normanskill Formation in angular unconformity. PAC 2 is represented by the Wilbur and Rosendale Members of the Rondout Formation and PAC 3 by the Glasco and Whiteport Members (the PAC numbering system, data and interpretations in Figure 4 are taken directly from Osborn's 1983 thesis and differ slightly from those presented in the text of this paper and Figure 21. An increase in the number of Rondout PACs at Kingston relative to Catskill indicates progressive stepwise onlap to the north over the Ordovician land surface during Rondout time.

STOP 6. South Wilbur
Abandoned quarry above road along Rondout Creek, . 5 miles southwest of Wilbur, New York.
Exposed at this locality are two PACs of the Binnewater Sandstone taken from Buggey, (1984), four Rondout PACs and eight Manlius PACs. Several observations and interpretations can be made at this locality.
1. There is an excellent correlation of PACs in the Manlius interval with those observed at Kingston localities A and B. Key correlation points include the major facies change to calcarenite at the base of PAC 7, the thin-bedded gastropod bearing facies which characterizes PACs 9 and 10 and the major facies change to thick-bedded stromatoporoid bearing calcarenite at the base of PAC 11.
2. More erosion at the Manlius-Coeymans cryptic unconformity has reduced the thickness of PAC 12 to about 1 meter. Note the minor paleokarst developed on the unconformable surface. 3. PAC 4 appears between PACs 3 and 5. The presence of this PAC to the south and its absence to the north is evidence of a minor cryptic unconformity . In the initial study of this interval Osborn (1983) recognized the facies change which now defines the boundary at the base of PAC 4 but did not set it off as a PAC boundary because it was absent at the northern localities (Fig. 4). Osborn placed this unit in the upper 2-4 feet of the Whiteport Member of the Rondout Formation at the Fourth Lake, Wilbur and Connelly localities. Interpretation of a cryptic unconformity at this level provides an explanation for these facies patterns.
4. The two Binnewater PACs preserved at this locality were shown by Buggey (1984) to be correlated with two PACs in the middle of the Binnewater Formation ten miles to the south at High Falls. This correlation leads to the interpretation of the Binnewater/Rondout contact as a cryptic unconformity at which at least two PACs are lost at South Wilbur.
5. Finally the High Falls and Binnewater Formations progressively and episodically onlap the underlying Ordovician Normanskill Formation as does the Rondout Formation at Kingston and to the north.

B: PREGLACIAL AND POSTGLACIAL DRAINAGE OF THE CENTRAL HUDSON VALLEY
"Robert J. Dineen
Room 3160, Cultural Education Center
The Problem
The preglacial drainage patterns of the mid-Hudson Valley have not been studied on a regional basis since the early nineteen-forties. These studies dealt with the meso- to macro-scale landscape features and their inferred relationships to Late Mesozoic and Early Cenozoic tectonism. They were limited by their reliance on the small scale and relatively crude maps and by the sparse subsurface information that were available at that time. The Holocene history of the area was only mentioned in passing in those studies because of the lack of information concerning Holocene features throughout the region.
Method
Abundant subsurface and surface data have been assembled during the nineteen seventies and eighties that can be used to illuminate the Late Cenozoic drainage history of the area. The modern topographic map and stereo air photo data that are available for eastern New York State can be used in combination with Cultural Resource Surveys, archeological studies, engineering reports, historical records, and newspaper accounts to develop a Late Holocene through Recent geologic history of this region. I have used a sampling of such data to prepare this preliminary report on the Cenozoic drainage of the mid-Hudson Valley from Newburgh to Catskill. I have chosen selected sites west of the Hudson River to illustrate key points in this report.

STOP 1: New Paltz Bedrock Terrace- SUNY at New Paltz Parking Lot
The section of the Wall Kill Valley near the State University College contains a sequence of strath terraces that range in elevation from the Hoogeberg to the Albany Peneplains. Several of these terraces are mappable in the lower Wall Kill Valley. Dissected and glacially scoured remnants of the Hoogeberg Peneplain occur along the western edge of the Marlboro Mountains. This surface is sharply truncated at Clintondale by a 400- to 420-foot surface that can be traced southwest to the State line. The 400- to 420-ft terrace is cut, in turn, by a 340- to 360-ft terrace. This terrace extends through the windgap in the Marlboro Mts known as The Hell. A third terrace lies at 280 to 300 ft. The SUNY at New Paltz campus is built on this terrace. The 280- to 300-ft terrace can not be traced south of Walden. It extends north into the Hudson Valley and west into the upper Rondout Valley.
The Ashokan Peneplain is preserved by the ridge line of the Shawangunk Mts. Monadnocks of the Helderberg and Monticello Peneplains remain as high points along the Shawangunks.

STOP 2: Wall Kill Floodplain
Intersection of Mountain Rest and Springtown Roads
The reach of the Wall Kill downstream from New Paltz is underlain by 200 ft of glacial-lacustrine deposits. These sediments fill a gorge that was cut into the Albany Peneplain during preglacial or interglacial time. The gorge narrows and becomes shallower to the south, and disappears between Wallkill Camp and Wallkill Village. The gorge underlies the Tillson area and passes west of the present Rondout Creek through the Eddyville area (Dineen and Duskin, 1987).
The abrupt widening of the Wall Kill's floodplain between New Paltz and Tillson is controlled by the preglacial topography. The soft glacial deposits allowed the Wall Kill to migrate laterally. Thus, the floodplain of the Wall Kill is 4,000 ft wide in the stream reach between New Paltz and Tillson. It narrows to 500 ft to the south. The floodplain is 15 to 20 ft above the level of the stream channel, and is underlain by 11 to 22 ft of floodplain deposits in the New Paltz area. These deposits tend to become finer-grained towards the surface. The sinuosity of the river in this reach is 1.6. The Wall Kill's floodplain contains Woodland through Late Archaic Indian artifacts, suggesting an age for the floodplain deposits of 700 to 5,000 yr (Len Isenberg, personal communication, Feb. 1987). The Wall Kill is deflected across a rock sill by the large glacial lake delta at Tillson (Dirieen and Duskin, 1987) and flows through a rocky channel to its confluence with the Rondout Creek. The bedrock sill is the base-level control for this reach of the Wall Kill.

STOP 3: Rondout Creek Floodplain at Napanoch
This section of the Rondout Creek's floodplain was mapped during a Cultural Resource Survey by Mr. Mark LoRusso of the NYS Museum (LoRusso, 1986). The floodplain north of the Eastern Correctional Facility is 2,000 to 3,000 ft wide and 6 to 20 ft thick. Several abandoned meanders are visible on its surface. It is developed downstream from a large alluvial fan that lies at the base of the Shawangunk Mountains. The floodplain deposits were intensely tested during the Cultural Resource Survey, but contained very sparse evidence of Indian occupations, although the meager sample of artifacts suggest an Archaic age (LoRusso, 1986).
The site is downstream from the large alluvial fan of the Rondout Creek at the Village of Napanoch. It was built where the Rondout enters its low-gradient middle valley. The upper Rondout drains the rugged foothills of the southern Catskill Mountains. The base-level of the central low gradient area is controlled by a bedrock sill at High Falls. The stream flows across deeply incised glacial lake deposits (Dineen, 1986) that fill a preglacial valley. The preglacial valley is graded to the Albany Peneplain, and is cut into the Ashokan Peneplain. The valley also erodes a section of the Hoogeberg Peneplain.

STOP 4: Esopus Floodplain at Old Tongore Road Town Park
This stop is at the alluvial fan of the Esopus Creek that was built where the Esopus flows off of the Ashokan Peneplain and onto glacial lake deposits that clog a valley cut into the Albany Peneplain. The Esopus Creek's base-level for this reach is controlled by a bedrock spillway at Glenerie Falls. The stream meanders across a 3,000 ft wide floodplain that is 12 to 20 ft thick (Stop 1 in Dineen and Duskin, 1987). The sinuosity of the stream is 1. 2 to 1.3 in this reach. Many oxbows are visible, especially near Kingston. Dr. Len Isenberg noted that many surface finds of Archaic artifacts occur on the surface of the Esopus Creek's floodplain (personal communication, Feb. 1987).
The buried valley contains a narrow inner gorge that is cut to sea level. The inner gorge extends south into the Marbletown area, although it narrows considerably. The Rondout-Esopus Valley contains a sequence of strath terraces that lie between the Hoogeberg and Albany Peneplains. The Albany Peneplain extends into the middle Rondout Valley through the High Falls water gap.

STOP 5: Kingston Point
The "inner gorge" of the Hudson is deeply incised into the Albany Peneplain in the Kingston area. The inner gorge attains depths of 205 ft below sea level. The Castleton strath terrace lies at -80 to -100 ft in this area. The irregular surface of the Albany Peneplain is probably caused by glacial scour of the weak shale beds that lie between the relatively resistant sandstone and limestone layers. The Albany Peneplain clearly extends south as far as the Newburgh-Beacon Bridge.
The Holocene deposits of this section of the Hudson's estuary are predominantly silty sand to sandy silt with abundant organic matter. The deposits overlie an unconformity that was carved into glacial deposits by the Hudson during the long period of lower sea level (12,000 to 4,000 yrs ago). The organic-rich silts and sands were deposited by the Hudson during the later stage of sea level rise. The Holocene unconformity lies at -20 to -30 ft at the Castleton Crossing of the Thruway, at -40 ft at the Rip Van Winkle Bridge, at -80 ft at the Kingston-Rhinecliff Bridge, at -120 ft at Poughkeepsie, and at -90 ft at the Newburgh-Beacon Bridge. The excessive depth at Poughkeepsie is somewhat puzzling, it might be caused by either the presence of a glacial kettle hole, by catastrophic floods during deglaciation (Dineen and Duskin, 1987) or by tidal scour.

STOP 6: Catskill Point
The bottom of the Hudson gorge is over 122 ft BSL at the Rip Van Winkle Bridge. It has been scoured into the Albany Peneplain. Remnants of the Hoogeberg Peneplain might exist at Mount Merino and the Becraft Mts., beyond the east end of the bridge.
The tidal flats and swamps south of the Village of Catskill are the Holocene delta of the Cats Kill. The tidal flats around Rogers Island are the southernmost extent of the Hudson's Holocene delta. Both of these deltas are composed of silty sand.

STOP 7: The Kaaters Kill at Timmerman Hill
The Kaaters Kill's headwaters are in the eastern edge of the Catskill Mountains. The stream flows across the remnant of the Hoogeberg Peneplain and into the Bakoven valley at High Falls. The Hoogeberg is underlain by sandstones of the Mount Marion Formation. The Bakoven valley is underlain by the Bakoven Shales and is bordered on the east by the relatively resistant carbonates of the Onondaga Formation and the Helderberg Group that underlie the Kalkberg (Chadwick, 1944). The Bakoven valley was eroded to sea level by the late preglacial Cats Kill. The Cats Kill entered the Bakoven valley through the dirt gap at Leeds Flats, flowed into the Esopus Valley at Mount Marion, and entered the Hudson's inner gorge through a dirt gap at Wilbur, near Kingston.
The Kaaters Kill flows between deeply incised clay bluffs. These rounded bluffs resemble Dutch colonial baking ovens, hence the name "Bakoven" for the valley (Chadwick, 1944). The bluffs are failing by a myriad of landslides as the Kaaters Kill undercuts their base when it overflows its narrow floodplain every spring. The clays are over 80 ft thick in the Bakoven valley and overlie shale-pebble rich esker gravels. The base level of this reach is controlled by the bedrock sill in the water gap at the Thruway's crossing of the Kaaters Kill.

STOP 8: Lower Palenville Fan
The next four stops will give us an opportunity to examine several features of the Kaaters Kill as it leaves its upland headwaters and debouches onto the Hoogeberg Peneplain or piedmont. The stream begins near North Lake (STOP 13) on the dip slope of conglomerates that are part of the Onteora Formation. It spills over the edge of the Helderberg Peneplain at Kaaterskill Falls and enters the Kaaterskill Clove. It has a high gradient in the Clove. The Clove is carved into the sandstones and shales of the Kiskatom Formation. Many knickpoints have developed on the sandstone beds in the Clove (STOPS 10 and 11). The gradient flattens somewhat when the stream exits from the Kaaterskill Clove and flows across the surface of the Hoogeberg Peneplain. A large alluvial fan has been deposited at the mouth of the Clove.
The Village of Palenville is built at the head of the fan (Fig. 10 and STOP 9). Abandoned braided stream channels (distributaries) traverse the fan's surface. The soil development is very poor on the surface of these sandy, cobbly gravels. The stream abandons its braided habit at the foot of the fan and meanders across the lake clays that mantle the Kiskatom Valley. The stream's gradient across the alluvial fan is 0.034 or 180 ft/mile.
STOP 8 is near the distal edge of the fan. The stream cut next to the the road exposes clean, open-work, imbricated cobbles that are interbedded with muddy matrix supported cobbly gravels. During low stream flow stages, the stream disappears into the open-work cobbles exposed in the streambed. Rock is exposed in the streambed and the stream flows across a rock ledge upstream at the bridge. Large swampy areas lie along the foot of the fan, thus many of the camps in that region are built on stilts.
The muddy gravels were probably deposited as either wet sediment flows during catastrophic floods or as sieve deposits left as the stream waters flowed into the highly permeable channel deposits, and the open-work cobble beds are probably channel deposits of more "normal" flows. The outcrops of ledge rock are "mini-hogbacks" of Mount Marion sandstones that have been incompletely covered by the fan. The stream channel is approximately at the the same height as the adjacent road, so the stream could break through the intervening levee and to spill onto the roadway, thus creating a new distributary!

STOP 9: Red House at Head of Fan, Village of Palenville
The head of the Palenville alluvial fan can be examined at this stop. The Kaaters Kill crosses a bedrock ledge as it exits from the Kaaterskill Clove. The stream gradient is abruptly reduced, causing the stream to deposit the coarse bed load that it carried in the Clove. Many 1-meter diameter clasts are deposited each Spring in the backyards of the people that live next to the creek. A significant number of these boulders are composed of limestone, a lithology that is not native to the Clove. The primary upstream source of limestone appears to be the rip-rap that is emplaced along the roadbed of Route 23A. These limestone clasts might have traveled a mile from their origin in the roadbed! The fan head is deeply trenched by the stream channel. It is composed of coarse-grained material.

STOP 10: Intermann's Bridge
The stream flows in a steep-walled valley upstream from STOP 9. The floodplain is thin in this section, exposures are less than 6 ft thick. The floodplain deposits are also very ephemeral in the Clove - they have been deeply scoured several times since 1890. The bridge and local houses have been swept away in those floods (Bonafede, 1980). The bridge's 1850 foundations are on rock and usually survive the floods, so they are reused in succeeding bridges. Landslides and rockfalls are common in the Clove (Fig. 10; Bonafede, 1980).
The records of the NYS Dept. of Transportation identify many landslides and seeps along the road from Intermann's Bridge to Moore's Bridge (the bridge near Fawn's Leap). The roadbed crosses a buried valley with over 100 ft of "hard to compact red clayey silt with angular gravel" (till) approximately mid-way between the two bridges. The records also note that the road was severely washed-out during a hurricane in 1935.

STOP 11: Fawn's Leap
Fawn's Leap is a geological feature that was made famous by the Hudson River School painters. It is a waterfall that is cut into the top of the Kiskatorn Formation (Fisher and others, 1970). It has formed where one of the major joint sets of the Appalachian Plateau crosses the Kaaterskill Clove (Chadwick, 1944). The Kiskatorn Formation is apparently more resistant to erosion than the overlying rocks; the Clove has a distinct V shaped notch below Fawn's Leap, with a wider, U-shaped valley above. The Kiskatorn Formation also forms steeper slopes along the Catskill Escarpment. Seeps and springs are common in the inner gorge, many of the landslides are associated with the seeps (Bonafede, 1980; NYS Dept. of Transportation).
The stream gradient is 0.040 or 211 ft/mile from Fawn's Leap to the head of the alluvial fan. The Kaaters Kill has carved potholes, grooves and a plunge pool at the falls. Bars composed of very coarse-grained, imbricated boulders occur in the stream channel up-and down-stream from Fawn's Leap. Luanne Whitbeck (personal communication, Fall, 1983) noted small trees growing on the bars that were of approximately the same age (-10 to 15 years old). She suggested that the trees indicate that the bars were not active in 1983, and that the trees probably began growing during a drought when the stream flow was low. She also observed active landslides along the channel sides.
The floodplain is still quite thin in this reach. Large alluvial fans or cones have been deposited at the mouths of the high-gradient tributary streams in the Clove. Air photo analysis and field work by Dineen, Whitbeck, and Lorie Dunn have documented abundant evidence for landslides, rockslides, earthfalls, and earthflows in this reach. Bonafede (1980) cites several nineteenth century maps that document similar features in the Clove.

STOP 12: Tannery Mill and East Hunter
This 0.5 to 0.75 mile hike follows the floodplain of the stream. The high embankment of Route 23a is on the right (north). Many examples of earthfalls can be seen in the channel banks. The exposures along the stream show that the floodplain deposits are 1 to 2 meters thick, and are composed of imbricated flat cobbles overla1n by a thin veneer of silt. The gradient of the stream in the reach from Haines Falls to Fawn's Leap is 0.046, or 241 ft/mile.
We will pass a large (3 by 4 by 4 meters in diameter) boulder on the bank that was called "Rockefeller Rock" because of an inscription carved into the sandstone (Bonafede, 1980). That boulder had moved 5 to 10 cm away from the bank from 1979 to 1984 (Martha Costello, personal communication, Winter, 1985).
Our trek ends at the defunct East Hunter Tannery. This tannery complex and village were built in 1817 and abandoned by 1866 (Bonafede, 1980). The village is being buried by mass movements. The tannery shows abundant evidence for stream scour and deposition. The mill dams that used to serve the tannery have been washed away.
Bonafede (1980) was not able to document the presence of artifacts that were more than 200 years old, in spite of an intensive search that included many shovel test pits. This observation suggests that the Clove gets "flushed out" regularly by. the Kaaters Kill, a hypothesis that is strengthened by the evidence for mass wasting and flooding and by Route 23A's severe maintenance problems (NYS Department of Transportation).
The "horseshoe" where the road crosses the Kaaters Kill below Kaaterskill Falls is underlain by over 49 ft of red glacial till, based on NYS Dept. of Transportation test boring data. Landslides occur frequently in the area of the horseshoe (Frank Irving, personal communication, Summer, 1987).

STOP 13: North Lake: Catskill Mountain House
The North and South Lake area is a State Park, and is the headwaters for the Kaaters Kill. It is developed on the dip slope of the Onteora Formation, the rock that forms the caprock of the Catskill Escarpment. Glacially striated conglomerates are exposed around the lakes. A major mountain inn served tourists in this area throughout the late nineteenth and early twentieth centuries (Bonafede, 1980). Its abandoned hulk burned about twenty years ago. The inn was built at the edge of the Catskill Escarpment.
The park is on the Helderberg Peneplain. The view from the Escarpment overlooks the Hoogeberg and Albany Peneplains. The Helderberg Plateau-Hamilton Hills are visible to the north. To the east lie the Taconic Mountains, and to the northeast the Rensselaer Plateau can be seen. The Rip Van Winkle and Kingston-Rhinecliff Bridges can also be seen from this vantage point.
The inn and the magnificent scenery lured many geologists into the North Lake area through the years. Darton (1895) suggested that the Kaaters Kill and the Platte Kill to the south have pirated the headwaters of the Schoharie Creek. These high gradient streams had a major advantage over the Schoharie in that they had only to flow 7 to 10 miles to reach their base level at the Hudson, while the Schoharie waters had to flow 135 miles to reach the same point.
Rodgers (1987) wondered why the piracy took place as late as the Pleistocene. He suggested that the back-tilted edge of the Onteora Formation was so resistant to erosion that it impeded the headward extension of streams in the Hudson Valley for a long time. He also suggested that the Kaaterskill Clove was excavated by the stream in post-glacial time.
The NYS Department of Transportation drilled through 65 feet of compact till along the right-of-way of Route 23A from Intermann's, Bridge to Haines Falls, so both the upper, wide valley of the Clove and the narrow gorge below Fawn's Leap are pre-Wisconsinan in age. The till must be studied in more detail to determine whether earlier glacial deposits are present.

C: STRUCTURE AND STRATIGRAPHY ABOVE, BELOW, AND WITHIN
THE TACONIC UNCONFORMITY, SOUTHEASTERN NEW YORK
Jack B. Epstein and Peter T. Lyttle
Reston, Virginia
In the early Paleozoic, carbonate banks lay along the east coast of the ancient North American continent. In Ordovician time, plate convergence commenced the closing of the ancient proto-Atlantic ocean (Iapetus) and a deep basin developed into which thick muds and dirty sands were deposited, These were later to harden and become the Martinsburg Formation. Later still, with continued compression, the sediments were folded and faulted during the complex deformation of the Taconic Orogeny. In the field trip area the trend of these folds and faults is about N 20° E. These structures become less intense westward. Following Taconic deformation, mountains rose to the east and coarse sediments were transported westward and deposited as sandstones and conglomerates of the Shawangunk Formation across beveled folds of the Martinsburg Formation. However, a thin diamictite with exotic pebbles records a heretofore unreported geologic episode which occurred during the Taconic hiatus, As the mountains were worn down, finer clastic sediments and carbonates were deposited more or less continuously through the Middle Devonian. Clastic influx during the Middle Devonian records a later orogeny, the Acadian, It is probable that the structural effects of this orogeny did not extend as far west as this field trip area; the limit of Acadian folds, faults, and igneous intrusions lies to the east. Finally, near the end of the Paleozoic, continental collision deformed all rocks, down to and below the Martinsburg. The trends of these later (Alleghanian) structures are more northeasterly.
On this field trip we will develop new interpretations of Ordovician and Silurian stratigraphy, demonstrate structural zones at the limits of Taconic deformation, investigate the relative effects of Taconic, Acadian, and Alleghanian deformation in southeastern New York, and discuss the strange goings-on in a thin enigmatic unit at the unconformity between the Martinsburg and Shawangunk Formations. We will see a variety of complex structures within three Taconic tectonic zones (Stops 1, 2, 5, 6, 7, and 8), examine the nature of, and deposits at, the Taconic unconformity (Stops 2, 5, and 8), review some of the proposed facies relationships in Silurian rocks (Stops 3, 7, and 8), and, weather permitting, look out over the regional geology from high atop the Shawangunk Mountains during lunch (Stop 4).
In the case of disastrous weather, alternate Stops lA and/or lB may be substituted for Stop 1. These stops would allow a brief look at a melange zone of Taconic age, albeit not as spectacular as at Stop 1, and a thrust fault zone of Alleghanian age, both in the Martinsburg Formation.

C: STRUCTURE AND STRATIGRAPHY ABOVE, BELOW, AND WITHIN
THE TACONIC UNCONFORMITY, SOUTHEASTERN NEW YORK

Leave parking lot of Ramada Inn Motel.
Locality is on blacktop of Holocene age, unconformably overlying stream and lake-bed deposits of Pleistocene (Woodfordian) age, unconformably overlying either the Onondaga Limestone or Bakoven Shale of Middle Devonian age.

Fault in the Bakoven Shale
About one third mile straight ahead on the north side of NY 28 is a fault in the Bakoven Shale (noted by Pedersen and others, 1976, p. B-4-21), The fault zone is about 5 feet thick and consists of crumpled and slickensided black shale with abundant quartz veins. The slickenlines and verging of the folds indicate that the overriding beds moved to the northwest.
Some workers believe that these are the youngest rocks deformed in the area and therefore date the folding in Silurian and Lower Devonian rocks as Acadian. However, we believe that there is evidence to suggest that this deformation is Alleghanian (see section on Age of Deformation).
2.1 miles northeast of the fault in the Bakoven is a fault duplex about 5 feet thick, slightly higher in the section in the Mount Marion Formation. Slickensides in the duplex indicate that the overriding beds moved N 70° W. Pedersen and others (1976, p. B-4-6, 7, 22,23) consider these structures to be soft-rock "pull aparts". However, a 1-foot-thick sandstone bed is deformed into mullions and is surrounded by slickensided surfaces and sheared shale. Tectonic shortening is estimated to be 50-60 percent, judging from the overlapping of the mullions.

Fault in Bakoven Shale described above can be seen to right.
For the next 8 miles we will be riding along a flat plain underlain by floodplain and stream-terrace deposits of Esopus Creek and glacial lake-bed sediments of Pleistocene Lake Stone Ridge (Dineen and Duskin, 1987).

Shales and sandstones of the Mount Marion Formation.
The hills in foreground to right are underlain by shales and sandstones of the Mount Marion Formation. In the hills above are sandstones of the Ashokan Formation. Valleys which trend N 20° E. are parallel to lineaments that are very apparent on radar imagery and topographic maps. The valleys, seen for the next two miles, are controlled by very closely spaced joints and minor faulting. The lineaments extend northward up into rocks as young as the Plattekill Formation of Middle Devonian age and may extend into the Oneonta Formation of Late Devonian age. Southward, these lineaments parallel faults that have been mapped in the Shawangunk Formation of Silurian age. This is one of the reasons for suggesting that the deformation in the area is Alleghanian, rather than Acadian, in age.

Cross Esopus Creek.
For the next several miles we will see scattered exposures of the Onondaga Limestone poking through glacial cover.

View of Mohonk Lake tower on Shawangunk Mountain at 2 o'clock.
The tower affords an excellent view of the Catskill Mountains, Walkill Valley, and surrounding region. It overlooks a gorgeous lake at the Mohonk Mountain House which is situated at the crest of a faulted anticline.

Outcrops of the Schoharie Formation.

Cross Rondout Creek.
Classic section of High Falls Shale, Binnewater Sandstone, and Rondout Formation to left.

Exposures of uppermost Shawangunk Fm in low cliff one block ahead

Canal Museum on left.

Cross Coxing Kill.

High Falls Shale, Binnewater Sandstone, and Rondout
Exposure of High Falls Shale, Binnewater Sandstone, and Rondout Formation in steep slope to left.

Mossy Brook Road on right.
If you hike about 0.5 mile down this road, which is on private land belonging to the Mohonk Mountain House, you will find an old log cabin. Nearby, the Mohonk Lake thrust fault is beautifully exposed in Mossy Brook, This gently southeast dipping fault carries Ordovician Martinsburg Formation northwestward over the Silurian Shawangunk.

Exposure of red beds of High Falls Shale on right.

Exposure of Shawangunk on right.

Cross Mohonk Lake thrust fault
Cross Mohonk Lake thrust fault, which carries shales of the Martinsburg Formation, here dipping moderately to steeply towards the southeast, northwestward over quartzites and conglomerates of the more gently southeast dipping Shawangunk Formation. This fault is not exposed where it crosses the highway.

Outcrops of the Martinsburg
For the next 0.7 mile we pass outcrops of the Martinsburg, consisting of thin-bedded shale, minor siltstone, and very rusty weathering, fossiliferous, fine-grained graywacke in beds up to 3 inches thick. Cleavage is poorly developed.

Exposures of slumped Martinsburg on left.
View of Catskill Mountains on right.

Straight ahead, and following the stream valley, is the Kleine Kill thrust fault.
To the right are exposures of deformed Shawangunk and the slope to the left is underlain by deformed Martinsburg.

Martinsburg in bank on right.
For most of this outcrop the southeast dipping shales and graywackes are right side up; however, there are several zones about 3 feet wide that are very tightly folded. The azimuth of these folds vary from N-S to N 10° E, and they plunge gently to both the north and south.

STOP 1A. FAULT ZONE IN FOSSILIFEROUS MARTINSBURG
The Martinsburg in this outcrop is dominantly medium dark-gray shale interbedded with fine grained graywacke. The graywacke beds are commonly less than 5 inches thick, and exhibit graded bedding, and parallel and cross laminations. The graywackes are fossiliferous (mostly brachiopods and crinoids) and contain a fair amount of pyrite. The fossils are most easily seen in the very rusty weathering pyrite-bearing graywacke beds. A cleavage is poorly to moderately well developed in the shales, although not enough to call these rocks slates.
The Martinsburg in this shale pit contains fault-related structures interpreted to be of two different ages. A melange or broken formation, best seen at the far north end of the pit (at least at the time of this writing), is part of the same melange zone seen at STOP 1. The melange zone is Taconic in age and has a strike of N 5-10° E. It has been carried westward over the Silurian Shawangunk in the hanging wall of the younger Kleine Kill thrust. Most of the small faults and slickensided surfaces that are common in this pit are probably related to this younger thrust fault. The trace of the Kleine Kill thrust nearby has a strike of N 15° E, and is interpreted to be Alleghanian in age.
Based on our mapping, several generalizations can be made about Taconic and Alleghanian fault-related structures. The fault zones in the Martinsburg which clearly do not cut Silurian and younger rocks generally have: a) a trend more northerly than the northeast-trending folds and faults in the Silurian rocks, b) a diagnostic scaly cleavage (see STOP 1 for a fuller discussion), c) tightly folded "floating" knockers of graywacke whose axes plunge predominantly to the northeast with variable azimuth, and 4) very little, if any, vein quartz. The faults that definitely cut both the Ordovician Martinsburg and the Silurian Shawangunk, and which we interpret to be Alleghanian in age, generally have: a) a slightly more easterly strike, b) well-developed "pencils" in the shales formed by the intersection of bedding and cleavage, and c) vein quartz parallel to bedding and/or cleavage that commonly contains shale fragments.
An example of a good Taconic melange can be seen at STOP 1, and an example of an excellent Alleghanian fault zone can be seen at Alternate STOP 1B.

View of Wallkill Valley to right (southeast).

Martinsburg shales to right and at bend in road.
Excellent exposures of Martinsburg shales to right and at bend in road. Thin-bedded, graphitic shale interbedded with thin- to medium-bedded, parallel-laminated, fine-grained, pyritiferous graywacke. Cleavage is poorly to moderately well developed and oriented nearly parallel to bedding.

Park on right and disembark.
Climb hill along dirt road with switch back, After walking approximately 1,000 feet you will reach the intersection of Forest Drive and Oakwood Drive; continue straight ahead on Oakwood Drive. Between here and Stop 1 Oakwood Drive marks the boundary between the lands of the Mohonk Mountain House and the Mohonk Preserve, which is also a hunting boundary.
PLEASE BE AWARE THAT BOW AND ARROW HUNTERS MAY BE LURKING IN THE WOODS. NO DEER IMITATIONS ALLOWED.
After about 1,800 feet you will cross Kleine Kill Road. Continue another 50 feet on Oakwood Drive and follow it around a sharp bend to the right (northwest). For the next 750 feet until we reach Stop 1, pay attention to the outcrops of Martinsburg on the right. You should be able to find tight folds, overturned bedding, slickensided fault surfaces with and without vein quartz, and tension gashes in sandstone beds. We will not spend much time discussing these rocks until we reach STOP 1.

STOP 1. MARTINSBURG MELANGE
At this stop we will see a good example of a tectonic melange within the Martinsburg Formation. As there are no identified "exotic" blocks in this melange, it perhaps should be called a broken formation (Hsu, 1968). As you can see by looking to the northeast, we are very close to the Shawangunk cliffs beneath Skytop Tower. Although there are no exposed contacts showing unfaulted Shawangunk resting unconformably on Martinsburg melange in the field trip area, there are several localities in the Rosendale quadrangle to the east where Silurian rocks directly on strike with Martinsburg melange zones show no comparable deformation or offset. In addition, mapping by Vollmer (1981) just southwest of Albany, New York documents a beautiful exposure of unfaulted Rondout Formation resting unconformably on top of Taconic melange in the Normanskill Shale. For these reasons we feel that this melange zone, as well as similar ones nearby in the Martinsburg, must be Taconic in age. In the Kleine Kill valley down the hill and less than 1,000 feet to the west of Stop 1, is the main trace of the Kleine Kill thrust fault, which a short distance to the north offsets and folds the Shawangunk, This fault is part of an imbricate splay, or perhaps a duplex. It would appear that the melange zone seen at Stop 1 and several other places along strike is always contained in the hanging wall of the Kleine Kill thrust fault. Since there are thrust faults that postdate and transport these melange zones, it is particularly important to document structures that appear to be diagnostic for the melanges. The most important feature which can be seen at this stop is a scaly, anastomosing, phacoidal cleavage that commonly exhibits shiny and smeared surfaces. In addition, bedding is very disrupted and many tight folds are rootless and "floating" in the phacoidally cleaved shale and siltstone. Both of these features are most easily seen by exam1ning the two to six inch graywacke beds. As one might expect, the hinge lines of the rootless folds show a significant range in orientation; however, they generally plunge moderately to steeply to the NNE. By carefully examining small scale structures such as asymmetric folds, minor offsets, and slickensides, it is possible to determine the sense of movement on some of the faults. What is difticult, if not impossible, to prove is whether an individual fault formed during the Taconic melange-forming episode or is related to the later, probably Alleghanian thrust system. It is possible, however, to show that although most small-scale structures show an east-over-west sense of rotation and a west-northwest transport direction, there are quite a few examples of thrusts with the opposite sense of movement.
There are two good exposures of the Kleine Kill thrust fault in the bed of the Kleine Kill just west of this stop. These outcrops are remarkably different from the melange seen here. They show sharp, planar, knife-edge faults with minor brecciation but no wholesale bedding disruption. They also contain many quartz slickensided surfaces. Most of these slickensides show an east-over-west thrust sense; however, a number of slickenlines are subhorizontal and suggest that there is a component of strike-slip displacement. The sense of movement is ambiguous, but appears to be left lateral. The shales near the fault commonly show an excellent cleavage (they are almost slates) and are beautifully pencilled.

Shawangunk Formation and the Mohonk TowerPlacemark
Excellent view to right of cliffs of the Shawangunk Formation and the Mohonk Tower. The hills in the middleground are underlain by shales and graywackes of the Martinsburg Formation, trending northerly with angular discordance under the Shawangunk.

Overturned shales and thin graywackes of the Martinsburg Fm on right.
There are a number of narrow fault zones with vein quartz. This outcrop is roughly on strike with Alternate Stop lB

World-renowned New York State orchards

Overturned Martinsburg shales and thin graywackes on right
Steeply dipping and overturned Martinsburg shales and thin graywackes on right. View of the Shawangunk cliffs at the Trapps straight ahead

Martinsburg with 2.5 ft graywackes on right.
Bedding appears to be right-side-up, however, the poorly developed cleavage in the shales dips steeply to the west suggesting that both bedding and cleavage have been rotated by faulting.

STOP 1B. FAULT ZONE AT GANAHGOTE--MARTINSBURG FORMATION
The shales and graywackes of the Martinsburg in this long roadcut have been severely faulted. This locality was chosen as an alternate stop in order to show the small-scale structures related to what we and others (Kalaka and Waines, 1986) interpret as a major thrust fault of Alleghanian age. Several difficulties arise when trying to document this age: 1) The extent and thickness of glacial materials in the Wallkill Valley prevents the reliable tracing of structures over great distances. 2) This locality contains no rocks younger than the Martinsburg of Ordovician age. Therefore, at this specific locality it is impossible to prove the fault is younger than Taconic. This fault was first referred to by Kalaka and Waines (1986) and they will probably visit this locality on Trip H (this guidebook).
There are at least two ages of quartz slickensides at this stop. The oldest slickensides are parallel to bedding, show movement to the northwest, and were later folded by the tight folds produced during faulting. Unfolded slickensides also formed along these late faults and again show east-over-west movement. In addition, vein quartz found along faults can contain broken pieces of shale. The faults vary in strike from N 10° E to N 50° E and dip gently to moderately to the southeast. Cleavage, though present throughout the outcrop, is more intensely developed near the NE-trending thrust faults. It is in these localities that the rock is intensely pencilled. Based on our mapping in this region, the best examples of pencil shales occur near the younger faults that cut both Ordovician and Silurian rocks, At this outcrop it is common to find bedding and folds abruptly truncated by faults, but the total disruption common to the melange seen at Stop 1 is missing. While one can find smearing along cleavage planes and some anastomosing fabrics at this outcrop, the pervasive scaly cleavage so beautifully developed at Stop 1 is also missing.
About 0.5 mile southwest of Stop lB along the Shawangunk Kill are a series of excellent exposures of the middle part of the Martinsburg that we are informally calling the sandstone at Pine Bush (see section on Ordovician stratigraphy). For a distance of at least 2,000 feet along Shawangunk Kill the entire section is overturned. These outcrops appear to be in the footwall of the thrust fault seen at this stop. However, the total width of the fault zone is not known and there appears to be some faulting at the west end of the Shawangunk Kill exposures. In addition, data from the nearby Delaware aqueduct suggests that the 2,000 feet of overturned Pine Bush might be a sliver caught in the fault zone. About 3.2 miles to the north of Stop lB on Route 299 (Roadlog mileage 21.6 to 22.4) a minimum of 4,000 feet (perhaps as much as 6,000 feet) of Martinsburg is overturned or close to vertical. Also, it would appear that the thrust is cutting up section towards the north since it is approaching the contact with the overlying Shawangunk Formation. It is most likely that this fault is the same as the Mohonk Lake thrust fault. They both have minimum offsets of several thousand feet. In the Mohonk Lake area, the stiff and thick-bedded Pine Bush is virtually absent and the thinner bedded shales and graywackes of the upper Martinsburg (Mamakating) do not appear to be regionally overturned. Locally, for distances of a few tens of feet the rocks may be tightly folded and overturned.

View of Shawangunk Formation on cliff face straight ahead.

Martinsburg on left

Martinsburg is well exposed
From here to the unconformable contact with the Shawangunk near the top of the mountain the Martinsburg is well exposed. The rocks are predominantly shale interbedded with thin-bedded (up to 5 in), crossbedded to planar laminated siltstone, and minor fine-grained sandstone. Soft-sediment slump folds are common in the siltstones. Cleavage is absent or very poorly developed, except near tight folds and narrow fault zones. Most of these folds and faults do not affect the overlying Shawangunk and must be Taconic in age. They trend from N 5° E to N 20° E, while structures in the overlying Shawangunk trend more easterly.

To the left is a turn off with a nice view of Wallkill Valley.

Buried contact of Martinsburg and Shawangunk.
This area of the "gunks" is very popular with rock climbers, often as "thick as pigeons" (R. Waines, oral commun., 1983). The contact is exposed at two spots about 400 feet southwest of the road at the base of the cliffs. Fairly regular and linear mullions are seen in the basal Shawangunk at the contact.

Pass under Trapps bridge.
Conglomerates and quartzites of the Shawangunk dipping moderately to the west.

Cross Coxing Kill.
Here the Coxing Kill valley coincides with the trough of a broad open syncline that plunges gently to the northeast. It is also the site of much nude bathing. For the next 0.5 mile we will begin to cross a broad open anticline that exposes a window of Martinsburg that is approximately 2 miles long.

Poor exposure of Martinsburg to left.

Exposure of basal Shawangunk to right
Exposure of basal Shawangunk to right with unconformably underlying shales of the Martinsburg exposed about 40 feet away. Dips in both units are very gentle and the angle of unconformity is as little as 2°. However, the divergence in strike is as much as 38°, with the strike in the Martinsburg being more northerly. The Martinsburg here is in the broad open-fold Taconic tectonic zone.

Cross Peters Kill.

Cross Sanders Kill.

Upturned beds in Shawangunk mark a fault here.

Overview on right of Rondout Valley
Overview on right of Rondout Valley, underlain by Upper Silurian through Middle Devonian rocks which are buried by a variety of glacial sediments, and the Catskill Mountains, underlain by Middle and Upper Devonian clastic rocks of the "Catskill Formation". Moderately dipping quartzites and conglomerates of the upper part of the Shawangunk on left.

Cross Stony Kill

Roadcut in tongue of the Shawangunk
Roadcut in tongue of the Shawangunk consisting of distinctive light- and dark-gray, crossbedded, slightly conglomeratic quartzite.

Cross Rondout Creek.

U.S. 209 follows the Rondout Valley
U.S. 209 follows the Rondout Valley, here underlain by rocks from the uppermost part of the Shawangunk Formation, then through a sequence of Upper Silurian through Middle Devonian limestones, shales, sandstones, and siltstones. Exposures are poor because of cover by glacial drift.

Cross Vernooy Kill.

Gravel pits in glacial delta
Gravel pits in glacial delta to right and lake clays of glacial Lake Wawarsing under flat plain to left (Rich, 1934; Heroy, 1974). Glacial Lake Wawarsing was dammed in the Rondout Valley between the recessional moraine at Phillipsport (mileage 65.2) and the retreating ice front. The top of the deltaic deposits are at approximately 600 feet altitude, showing that the lake was about 300 feet deep here. The lake enlarged during recession, it dropped as lower outlets were uncovered, and finally drained as the ice retreated past the northeast end of the Shawangunk Mountains near Rosendale.

Sand and gravel pit to right.

Eastern New York Correction Facility
Eastern New York Correction Facility, a maximum security prison, servicing many gentlemen from the New York City area, to left. There is an excellent exposure of the Martinsburg-Shawangunk contact, about 20 feet long, at an altitude of 600 feet. The angular discordance between the two formations is 4°; the Martinsburg here is in Taconic tectonic zone 3. The Shawangunk dips 22° NW in the northwest limb of the Ellenville arch. Mullions are prominent on the basal Shawangunk surface, and there is a shear fabric in both the Martinsburg and Shawangunk.

View of the Shawangunk Mountains in the NW-dipping limb of Ellenville arch to left.

Mount Marion Formation
Exposures of shaly siltstone to very finegrained sandstone of the Mount Marion Formation, dipping 56° NW, to right. Field to left covered by glacial deposits except for one exposure of Onondaga at airfield.

Cross Beer Kill.
A fine example of a slump deposit with disrupted bedding in the Mount Marion Formation is exposed 800 feet up the creek to the right. This outcrop may be within the Alcove Conglomerate of Wolff (1977).

View of North Gully in Shawangunk Mountain straight ahead.

Cross Sandburg Creek.

The Ellenville zinc-lead mine and a rock quarry
The Ellenville zinc-lead mine and a rock quarry in the tongue of the Shawangunk are located at the base of the mountain to the left. See Sims and Hotz (1951) and Rutstein (1987, p. 116) for descriptions.

Cross North Gully
Exposures of the tongue of the Shawangunk in roadcuts and tongue of the Bloomsburg in the creek bed of North Gully to the left.

Red beds of tongue of the Bloomsburg to left.
Till and moderately NW-dipping Shawangunk higher along road towards Mt. Meenahga.

View to right
View to right of the valley of Sandburg Creek, the Nevele Country Club, and the Catskill Mountains.

Conglomerates of basal Shawangunk on left.

Uppermost Martinsburg on left.

Contact between Martinsburg and Shawangunk at base of low cliff on left.

STOP 2. CONTACT OF MARTINSBURG AND SHAWANGUNK
CONTACT OF MARTINSBURG AND SHAWANGUNK; SHALE-CHIP GRAVEL AT TACONIC UNCONFORMITY; UPPERMOST MARTINSBURG IN TACONIC OPEN-FOLD FRONTAL ZONE; CLEAVAGE IN SHAWANGUNK
Take a peek to the northwest through the bushes at the broad glacial valley of Sandburg Creek and the Catskill Mountains beyond. The valley is underlain by glacial lake sediments, deposited in glacial lake Wawarsing between the morainal dam at Phillipsport, 5 miles to the,southwest, and the receding ice front. Also note the graffiti-covered, unevenly and planar bedded conglomerates with low-amplitude channels in the lower Shawangunk Formation. The contact with the underlying Martinsburg Formation is near the base of the low cliff. In this area the strike of the two formations is similar, but the Martinsburg dips 10 to 15 degrees less than the Shawangunk.
Locality A:
Walk 300 feet down the road to the exposed contact of the Martinsburg and Shawangunk.
The Shawangunk consists of planar bedded, quartz-pebble conglomerate with rounded to subangular vein quartz pebbles as much as 2.5 inches long, and planar bedded and crossbedded, conglomeratic, medium- to coarse-grained, feldspathic quartzite. Chert pebbles are rare. There are no pebbles derived from the underlying shales and graywackes of the Martinsburg Formation.
The Shawangunk forms a two-foot overhang above the underlying rock, which is at least 1.5 feet thick and consists of a mass of shale chips with an openwork texture. The chips are up to about 1 inch long and form a crude foliation approximately parallel to the overlying contact with the Shawangunk, although this foliation is interrupted in places. It might be suggested that these rocks were jammed by man under the Shawangunk, but the unit below the Shawangunk is clearly in place. The only explanation for this unit that we can think of is that it is a shale-chip gravel, deposited on and derived from a sloping Martinsburg surface. The shale chips are flat and generally equidimensional on their flat surface. There is no secondary cleavage in the chips, as far as we can tell. This suggests that cleavage was not imposed upon the Martinsburg prior to the deposition of the gravel. Thus, slaty cleavage at this locality did not form during Taconic deformation.
The gravels in the Martinsburg are remarkably similar to Pleistocene shale-chip gravels derived from Paleozoic shales in the central Appalachians, both in physical appearance and size-distribution characteristics.
If this is indeed a colluvial deposit, the geologic relations in this area indicate that the Martinsburg was gently folded during Taconic deformation, it was uplifted and exposed with a steep enough slope to develop a colluvial shale-chip gravel, and was later covered by conglomerates (believed to be fluvial) of the Shawangunk Formation.
Locality B
Walk another 700 feet down the road to exposures of uppermost Martinsburg bedrock,
The Martinsburg here consists of thin-bedded grayish black shale with some thin beds of olive-gray, very fine grained, crossbedded graywacke, capped by thin Pleistocene till. Note the lack of cleavage in the shales. The Shawangunk 40 feet above has the same strike, but dips 10° more steeply. This gentle angular discordance between the two units is typical not only for the Ellenville area, but for many miles to the northeast (to Ruedemann's Line, fig. 9) and to the southwest through New Jersey into eastern Pennsylvania (Epstein and Lyttle, 1987). This relationship is typical of the open-fold Taconic frontal zone.
Locality C
Walk another 600 feet downhill to the road intersection and the Shawangunk outcrop.
Bedding in the Shawangunk dips 40° NW here, getting steeper as we head farther northwestward into the steep limb of the Ellenville arch. The conglomerates in Shawangunk contains closely spaced fractures cutting through the quartz pebbles and sand matrix. In places a residual thin film of mica and opaque minerals along the cleavage folia shows that this is a pressure-solution phenomenon. This type of cleavage is common in the Shawangunk in New Jersey and New York. Because bedding-plane slickensides are not common in this area, it is hypothesized that shortening during folding of the Shawangunk was taken up by development of cleavage. In eastern Pennsylvania, where folding is tighter and there has been much accommodation by bedding-plane slippage, there is little cleavage in the conglomerates and quartzites.

Tongue of the Bloomsburg Redbeds on left.
The road follows this unit for several hundred feet.

Outcrops of uppermost Shawangunk in flatirons on NW limb of Ellenville arch.

Cross South Gully.

Site of Stop 3 on left.

STOP 3. Stratigraphy And Sedimentation Of The Shawangunk Formation
Pull off on shoulder to right. Cross road and walk 0.1 mile down to Stop 3.
CAUTION--WALK ONLY ON SHOULDER. THIS ROAD IS HEAVILY TRAVELLED! NO REFUNDS IF YOU ARE HIT.
The upper half of the Shawangunk Formation is exposed here and consists of cross-bedded and planar-bedded conglomeratic quartzite and pea-gravel conglomerates, with minor thin, lenticular light-olive-gray shale. Channels are abundant and many beds pinch out along strike. Shale drapes in crossbeds are common. Flattened silty shale balls up to 8 inches long are seen on the lower exposed bedding surface. Crossbed trends throughout the area of this field trip are to the northwest. The sedimentary structures, current trends, and petrographic characteristics suggest a fluvial, braided stream environment of deposition, similar to the interpretation for the Shawangunk in eastern Pennsylvania (Epstein and Epstein, 1972).
We will discuss some of the regional stratigraphic correlation shown in fig. 3.
The beds dip about 45° NW, They are interrupted by a kink fold whose axis trends 18° S 56° W, a more easterly trend than the regional strike of the beds. This fold, and scattered others in this part of the Appalachians, may represent a later stage of Alleghanian folding.
If the leaves are off the trees, you may be able to see the linear valleys in the Catskill Mountains to the north. These are discussed under "Age of post-Taconic Deformation".

Small thrusts in Shawangunk to left.
These have a strike similar to the kink axis at Stop 3 and may also be later structures.

Upper quartzite member of Shawangunk.
Launch site for hang gliders straight ahead.

Shale unit of Shawangunk on left.

Back into overlying quartzite unit.

STOP 3A.
Shale unit of Shawangunk to left, nice view at turn off to right. Pull off for Alternate Stop 3.
To the right (northwest) is the flat-floored valley of Sandburg Creek underlain by glacial lake clays, In the far distance to the north the hills are underlain by sandstones of the Ashokan Formation, and in the far distance to the north are the higher Catskill Mountains underlain by Middle and Upper Devonian rocks of the "Catskill Formation". The valleys in the Catskills are aligned along linears that are presumably controlled by structural weakness (see section on age of deformation),
CAREFULLY CROSS THE ROAD
In this area we have been able to divide the Shawangunk into lower and upper units (fig. 3), separated by a shale-bearing sequence about 100 feet thick, The shale unit underlies topographic lows, generally allowing for easy mapping. This unit can be seen at the base of the exposed section, and consists of more than 80 feet of interbedded, laminated, ripple laminated, olive-gray silty shale and moderate-brown and light-olive-gray very fine to medium-grained, crossbedded, lenticular sandstone, slightly conglomeratic in places. Many of the sandstones have sharp channeled bases and some are ripple-topped.
The shale unit is overlain by several hundred feet of thin- to medium-bedded, medium-grained, partly conglomeratic, partly feldspathic, crossbedded, channeled quartzite with scattered thin and lenticular olive gray shale. The quartzites appear to be evenly bedded from a distance, but closer scrutiny shows that they are channeled, lenticular, and unevenly bedded.

Mostly glacial till
Between here and the next stop, the road will be mostly on glacial till, with a few scattered exposures of the Martinsburg.

Martinsburg exposure on left.
This exposure and a few more up the road are in the Taconic tectonic zone of broad open folds. Views of continuous cliffs of the Shawangunk Formation in the broad top of the Ellenville arch may be seen at several places along this road.

Borrow pit on right in Martinsburg.

Entrance to Ice Caves Mountain National Landmark.
If you are quick you might read the educational (??) signs as the bus proceeds.
It is possible that we will not drive to the top of the mountain at Sam's Point. If so, pick up a lunch and take a leisurely 15-minute stroll to Sam's Point along the road to the right. The basal Shawangunk is nicely exposed near the end of the journey.

Slot Rock, a crevasse in the Shawangunk, on your right.

Martinsburg on right.
At this locality the Martinsburg dips 5° more steeply to the southeast than the Shawangunk exposed in the low cliffs above.

Cross Martinsburg-Shawangunk contact.

Lake Marentanza on right.
Many of the Shawangunk surfaces contain glacial striae.

Lake Marantanza
Lake Marantanza, partly dammed by till in a structural depression, on right.

Sign: "There are no fish in this lake...
Sign: "There are no fish in this lake. This is Lake Marentanza. It is the water supply for Ellenville. There are no fish because the rocky bottom does not grow plant life to give off enough oxygen to support fish life. It is a mystery where the water comes from since the lake is on a mountaintop. What do you think?"

STOP 4. SAM'S POINT
REGIONAL OVERVIEW; BASAL SHAWANGUNK; TROUGH CROSS BEDDING; GLACIAL STRIAE; ICE CAVES AND JOINTS; LUNCH
The highest point in the Shawangunk Mountains (2,289 ft) lies 2,000 feet north of this point. From southeast (left) to north (right), you can see (if the day is clear), the New York Highlands underlain by Precambrian rocks thrust on top of Cambrian and Ordovician carbonates and shales of the Wallkill Valley. In front of the Highlands are Schunnemunk and Bellvale Mountains underlain by conglomerates and sandstones of the Middle Devonian Schunnemunk Conglomerate in the Green Pond outlier. The rocks of the outlier are in fault and sedimentary contact with the Precambrian. The details of these structures are far from fully known. Shawangunk and Kittatinny Mountains, held up by the Shawangunk Formation, upon which we stand, next wiggle to the southwest with Tristates Monument marking the highest elevation in New Jersey at High Point (1,803 ft). We already know about the glaciated valley northwest of the mountain. The large white buildings 17 miles due west near Monticello make up the Concord Hotel, the site of several past GSA meetings, Beyond that are the Pocono Mountains of Pennsylvania that blend into the Catskill Mountains of New York to the northeast, underlain by flat-lying rocks of the "Catskill Formation".
The Shawangunk at Sam's Point dips very gently to the northeast, near the broad crest of the Ellenville Arch. Trough crossbedded is well exposed. These indicate current trends ranging between S 80° W and N 70° W. Glacial striae with chatter marks on the bedding surfaces show that the Wisconsinan glacier flowed over the mountain moving S 16° W.
The lower 80 feet of the Shawangunk here consists of medium- to thick-bedded conglomerate with quartz pebbles as much as 2 inches long. Channeled bases are common. Nowhere do we see any pebbles from the underlying Martinsburg, a peculiarity that exists throughout New York, New Jersey, and eastern Pennsylvania, and one which eludes a good sedimentologic explanation.
The Shawangunk is separated into huge blocks tens of feet wide. These have moved apart along the soft shales of the underlying Martinsburg, probably forced apart by frost action and wedging of boulders that fall into the cracks, producing a "moveoutite". This process has gone to a joyous extreme at the Ice Caves, one-half mile to the east, where the joints parallel the cliff face of the mountain. Cold air is trapped in the maze of blocks, and snow may persist throughout the summer, hence their name.

Proceed down over cliff of Shawangunk conglomerates
Proceed down over cliff of Shawangunk conglomerates, crossing buried contact with Martinsburg Formation.

Note the breaking away of large blocks of the Shawangunk along joints

At 11 o'clock are linear valleys in the Catskill Mountains
At 11 o'clock are linear valleys in the Catskill Mountains that mark lineaments seen on radar imagery and described under mileage 1.3.

Mount Marion Formation.
Moderately northwest dipping gray shale, siltstone, and sandstone of the Mount Marion Formation. We will be paralleling these rocks for the next 18 miles. On the left are lake deposits of Lake Wawarsing. This lake was dammed by the moraine at Phillipsport, four miles to the southwest.

Bear Hill to left in Ellenville arch.

Cross Homowack Kill.

Moraine at Phillipsport on left.

Leave moraine.

Parking area on right from which to see gliders on lazy summer days.

Shawangunk mine (zinc-lead)
Wurtsboro airport on left. Shawangunk mine (zinc-lead) on top of Mountain to left (Ingham, 1940; Gray, 1961).

Danny's Restaurant
Danny's Restaurant on left is excellent place for pastrami and corned beef sandwiches.

Exposures of Mount Marion to right.

Cross Basher Kill.

Large erratics of Catskill sandstone on left.

Quarry in New Scotland Formation on left.

Beginning of exposures of Shawangunk Formation on left.

Northwest dipping Shawangunk straight ahead.
In quarry to left are thin shales interbedded with typical Shawangunk quartzites and conglomerates. These are on line with exposures 1.2 miles to the southwest to which Swartz and Swartz (1931) applied the name "Otisville Shale Member of the Shawangunk Formation". This unit is out to lunch, that is, it is poorly defined, should be discarded. It is unmappable, and Clarke (1907) measured the rocks in the quarry and showed that shale makes up less than 3 percent of the section.

STOP 5. TACONIC UNCONFORMITY AT OTISVILLE
This is a classic exposure, discussed by many geologists in the past (Clarke, 1907, Schuchert, 1916, others), and visited by the 34th Meeting of the NYSGA (Fink and others, 1962). All have recognized the angular discordance in bedding between the Martinsburg (N 16° E, 44° NW) and Shawangunk (N 30° E, 28° NW). In this area we are in the broad open-fold zone of Taconic deformation, although these gentle structures are interrupted locally by a faulted overturned fold, seen at the next stop.
The basal Shawangunk conglomerates contain quartz pebbles as much as 2 inches long. No pebbles from the underlying Martinsburg were seen. The lowest few inches is pyritized. The Martinsburg comprises shale with minor thin graywacke siltstones and contains no obvious secondary cleavage.
The basal surface of the Shawangunk is irregular, with downward-projecting mullions that have a relief of about one inch and are about 3 inches to two feet apart. These have a general trend of N 32° E, about parallel to the strike of the beds and perpendicular to the regional transport direction. Note that these mullions are found only at the Martinsburg-Shawangunk contact and are not found on any surface higher up in the section. Some of the lowest Shawangunk is sheared parallel to bedding,
Between the solid Martinsburg bedrock and the Shawangunk there is an unusual zone, as much as one foot thick, containing light-gray to light-bluish gray clay gouge with slickensided quartz veins. This gouge, and the associated mullions in the overlying conglomerates, are typical of most Martinsburg-Shawangunk contacts exposed in southeastern New York and shows that the unconformity is also a plane of movement, the displacement along which is not known.
Also in this zone is a poorly sorted and vaguely bedded diamictite (a non-genetic term referring to a poorly sorted sedimentary rock with a wide range of particle sizes) containing angular to rounded pebbles of exotic types, as well as clasts from the Martinsburg, in a clay-silt matrix. Bedding is generally poor, but some samples collected from the northeast side of the cut show reasonably decent bedding. There is a sharp contact with the Shawangunk above and also a sharp contact with the Martinsburg below; both are unconformable. In places it appears that parts of the Martinsburg have been bodily lifted from the underlying bedrock and incorporated in this diamictite. There are several possibilities for the origin of this unit. We do not believe that it is fault related, because there is no foliation in it. It looks more like a product of mass wasting, and is interpreted to be a colluvial gravel.
The pebbles include types foreign to the immediately underlying bedrock, They are composed of fairly clean quartzite, some of which are pyritic, fine-grained protoquartzite and subgraywacke, red siltstone, medium-gray siliceous siltstone, laminated micaceous siltstone, medium dark-gray shale, graywacke, and vein quartz. Many are rounded, some have a thin weathering rind, and others have surfaces that are weathered in relief. Clearly, these cobbles were exposed to the air, weathered, and incorporated in the diamictite.
One question that needs to be asked is why the clay has remained a sticky clay, whereas surrounding rocks have been lithified? The answer may be that the contact is a zone of alteration. This area of the Shawangunk Mountains contains several abandoned lead-zinc mines and there are many prospects and mineralized localities throughout the area. The lower few inches of the Shawangunk here at Otisville is similarly altered.
Another puzzlement is that the colluvium contains many disoriented clasts of slickensided vein quartz. This indicates fault movement prior to incorporation in the colluvium. Possibly the Martinsburg nearby was faulted and slickensided during Taconic deformation and the slickensided fragments were later incorporated in the colluvium. Another possibility is that the diamictite is a fault gouge and not a colluvium, and there has been several periods of movement, the latest one of which fractured earlier slickensided rocks. The problem with this interpretation is that it does not account for the exotic pebbles nor does it explain the lack of foliation in the diamictite.
WHAT DO YOU THINK?

Covered contact of Martinsburg and Shawangunk.
Exposures of Martinsburg shale and graywacke on left, dipping moderately northwest.

STOP 6. OVERTURNED TACONIC FOLD IN MARTINSBURG FORMATION
The Martinsburg in the Otisville area is generally within the open-fold Taconic frontal zone. However, this locality is complicated by a faulted overturned fold (fig. 17). The Martinsburg here consists of shale and interbedded thin- to thick-bedded graywacke. Sole marks (grooves, flutes, and loads) are prominent on the undersurfaces of bedding in the overturned limb. Cleavage is well developed and is axial-planar to the fold. The axis of the fold trends about N 10°E and is overlapped by the Shawangunk about 1.3 miles to the north. Because the Shawangunk does not appear to be folded at the unconformity, the fold, faults, and cleavage in the Martinsburg at this locality must be Taconic in age. Outside the area of this fold, cleavage is generally not developed. While the map is believed to be accurate, critical parts lie within the boundaries of both a State and a Federal maximum security prison. These areas have not as yet been mapped. The criminal instincts of the senior author of this guidebook may allow him to set up residence here in the near future in order to complete the mapping.

Road to Federal Correctional Institution to left.

Otisville Correctional Facility
Otisville Correctional Facility of the New York State Department of Correctional Services to left. At this point, all those who have disagreed with the interpretations presented on this field trip will be dispatched.

Graywackes of the Martinsburg Formation on left

Lake Altemont on left
Lake Altemont on left; gently dipping Martinsburg shales on right.

Thick bedded graywacke and shale of the Martinsburg on left.

Martinsburg graywacke and shale on right.

STOP 7 ROUTE 17 ROADCUT
STRATIGRAPHY AND STRUCTURE OF THE UPPERMOST MARTINSBURG, THE TACONIC UNCONFORMITY, AND LOWERMOST SHAWANGUNK.
CAUTION. DO NOT FALL OFF ROADCUT. DEATH WILL RESULT
A fine view may be seen from this point. Far to the east (right) are the Schunnemunk and Bellvale Mountains, underlain by the Schunnemunk Conglomerate of Middle Devonian age in the Green Pond outlier. The lowland immediately to the east is the Walkill Valley, underlain by carbonate rocks of Cambrian and Ordovician age, as well as the Martinsburg Formation. Directly under us is a marvelous 3000-foot-long exposure demonstrating the stratigraphy and structure within the Martinsburg. To the west (left) you can see the overlying Shawangunk conglomerate (STOP 8), as well as the tongue of the Bloomsburg and overlying tongue of the Shawangunk. Beyond the bend in the road, and not seen, is the High Falls Shale. Off in the distance are the Catskill Mountains with rocks as young as the Plattekill Formation of Middle Devonian age.
This outcrop offers the best look at the uppermost 60U feet of the shale and graywacke at Mamakating of the Martinsburg exposed anywhere in the Wallkill Valley. Some of the more interesting sedimentologic and structural features are described below and located on figure 18, so that at some future date the field tripper can return and look at the outcrop at his or her leisure. As mentioned in the section on Ordovician stratigraphy, the Mamakating in southern New York differs from both the Ramseyburg and Pen Argyl Members of the Martinsburg that have been mapped in eastern Pennsylvania and northern New Jersey. The Mamakating consists dominantly of thick sequences (hundreds of feet) of medium dark-gray, thin-bedded shale interbedded with with very thin to medium-bedded (1/4 to 15 in), very fine to fine-grained, graywacke. These thick sequences alternate with thinner sequences (generally less than 100 feet) of thin-bedded shale interbedded with medium- to thick-bedded (up to 6 ft), fine-grained graywacke. Locally in both sequences, graywacke makes up more than 50 percent of the outcrop, but a more common average would be less than 25 percent. Only seen at this outcrop, but probably present elsewhere in the Mamakating, is a 40 foot thick olistostrome (fig. 19, near location B, specifically all rocks at ground level between station 50 and 300; fig. 18) with slump folds, flute casts, randomly oriented fissile shale chips, and imbricately stacked thin graywacke beds in a dominantly shale matrix, all of which suggest westward flowing currents. The olistostrome is dominantly shale, but contains some coherent graywacke beds which have incorporated some folded shale rip-ups. Perhaps earthquakes triggered slurries of slump deposits which were then immediately followed by turbidites which ripped up the shale. This olistostrome appears to be in the hanging wall of a back thrust of unknown displacement. A return to this exposure at a later date would be well worth the effort.
Near locality A on Figure 18 is a minor 2 inch thick bedding plane fault at the base of a foot thick graywacke bed. Another 60 feet east (at station 480 on fig. 18) is a graywacke bed with breccia at its base. The breccia contains quartz and calcite crystals and slickensides at its base. The upper block appears to have moved to the southeast.
The most obvious features seen from this vantage point are a number of faults (fig. 18, location C) directly across the highway. All of these structures trend in a more northerly direction than bedding in the overlying Shawangunk, and comparable disruption is not seen in the Shawangunk. Therefore, it seems most probable that these structures are Taconic in age. The thrust fault on the east (right) side of this tepee-like structure has an east-over-west sense of motion, and has produced an excellent cleavage in the gently arched adjacent rocks of the hanging wall. This is all the more evident because cleavage is not well developed, if at all, at Stop 7, except near faults. It is difficult to prove, but this fault is probably the one with the greatest displacement. Framing the west side of this tepee-like structure is a back thrust with unknown, but probably less, displacement. This back thrust cuts a bedding plane fault that probably has had minor movement with most of the strain taken up in little buckle folds, narrow breccia zones, and fractures. In between the two are a host of accommodation faults, which are trying heroically to solve the room problem. With a little patience it is possible for the field tripper to work out a chronology of movement among the many little faults in this area.
About 250 feet to the west (fig. 18, location D) is a complex area with faults of three different ages. From our vantage point across the road it is impossible to see these details, but it is worth discussing. The earliest movement is parallel to bedding and produces quartz slickensides, These slickenlines plunge N. 60° W. and show that the upper block moved northwest. The bedding plane faults are cut by a very steep fault oriented N. 83° E., 80° SE. which has a 6-12 inch gouge. Down-dip slickenlines show that the south block moved up in this case. This steep fault is in turn cut by a third fault oriented approximately N. 70° E., 50° NW, This cross structure may be a much later Alleghanian feature similar to the late kinks seen at Stop 3. Movement on this youngest fault folds the second steep fault and shows down-to-the-northwest movement.
At the 1175 foot marker on Figure 18 (near location E) are beautiful fractures filled with calcite, brecciated shale fragments, quartz, and a brownish-orange carbonate mineral (probably ankerite). These vertical fractures, seen at road level, are oriented N. 11° E. and appear to be caught up in a fault zone about 20 to 25 feet above road level. This fault reaches road level at station 1300 on Figure 18. We interpret this thrust fault as a backthrust, based on folding of bedding in the upper block (presumed hanging wall) and the sense of rotation of the vertical fractures. Some of these fractures were the locus of later movement as evinced by slickenlines oriented 11° 0 N. 11 E.
From station 1300 (fig. 18) west to the contact with the unconformable contact with the overlying Shawangunk at Stop 8, the Mamakating dips gently northwest and is devoid of any complex structures.
D. W. Fisher made three collections of graptolites from the Martinsburg shales of this outcrop, which were reported on by W. B. N. Berry (1970), The species reported by Berry are: Climacograptus spiniferus Ruedemann and Climacograptus typicalis Hall from 16 feet below the contact with the Shawangunk; Climacograptus sp., Dicranograptus nicholsoni var. minor Bulman, and Orthograptus quadrimucronatus var. approximatus (Ruedemann) from 49 feet below the contact with the Shawangunk; and Dicranograptus nicholsoni var. minor Bulman from 138 feet below the contact with the Shawangunk. These fossils are of critical importance to the dating of Taconic events (see section on Ordovician stratigraphy in text) and in establishing the length of the hiatus represented by the Taconic unconformity in southern New York State. Berry puts these graptolites in his upper subzone of zone 13, which suggests the rocks are late Middle Ordovician to early Late Ordovician in age.
Just to the south of where we are standing and approximately 240 feet beneath us is an old abandoned railroad tunnel that Russell Waines kindly suggested we visit. The southeastern 3,400 feet of this tunnel is in the Martinsburg, while the northwestern 400 feet offers excellent exposures of Shawangunk. The mineralized unconformable contact is especially well exposed (for details see Stop 8). Interestingly, a long section of the tunnel that is bricked over so that no rocks can be seen coincides with the most faulted section of the Martinsburg (fig. 18, between localities C and E). A thirty foot wide thrust fault zone (located about 400 feet in from the southeastern end of the tunnel) which, if projected along strike, would be located about 1,000 feet east of the long roadcut of Stop 7. For anyone enterprising enough to visit this tunnel, we would highly recommend a hard hat, and even more importantly, a pair of chest waders at least 5 feet tall; there is always a great deal of water in the north end of the tunnel.

Excellent exposure of olistostrome
Excellent exposure of olistostrome showing slump folds in thick graywacke on left beneath overpass

STOP 8. MARTINSBURG-SHAWANGUNK CONTACT STRATIGRAPHY OF THE SHAWANGUNK-BLOOMSBURG INTERVAL
BE VERY CAREFUL OF HIGH-SPEED TRAFFIC.
This is another fine exposure of the Taconic unconformity in southeastern New York. The rocks of the Martinsburg and Shawangunk are similar to those we have seen elsewhere. The basal foot of the Shawangunk contains much pyrite. The Martinsburg at the contact dips 16° to 31° NW., whereas the Shawangunk dips 25° NW. The angular discordance at eye level is 15°. No secondary cleavage is seen in the Martinsburg at this spot. Graptolites of Zone 13 age (late Middle to early Late Ordovician) were identified by Berry in the Martinsburg within 135 feet of the overlying Shawangunk (Offleld, 1967, p. 53; Berry 1970; see Stop 7).
The character of the zone between the Martinsburg and Shawangunk varies from place to place. Near road level, the zone contains rotated shale fragments with some quartz veins. This is probably a shear zone. Also included in this zone are disrupted shale fragments and a medium dark-gray sticky clay, a fault gouge. To the southeast, where the contact rises to about 20 feet above road level, we found rounded to subangular pebbles and cobbles up to 4 inches long of graywacke, chloritic sandstone, cross-laminated feldspathic conglomeratic quartzite, and red very fine-grained sandstone. Small ribs on the surface of one pebble prove that the clast was weathered prior to emplacement, and is not a fault-breccia fragment. Several pebbles also have distinct weathering rinds. The shape of the pebbles suggest transport of short distances.
As indicated in the section on stratigraphy at the beginning of this guidebook, these findings suggest that there were a series of Upper Ordovician and possibly Lower Silurian rocks that were deposited upon the Martinsburg following Taconic uplift and folding. These were derived from source rocks that are now gone. The potential source areas are presently under investigation.
About 1,000 feet to the west we can see fine exposures of the tongue of the Bloomsburg (called High Falls by Gray, 1961, and Otisville Shale and High Falls by Smith, 1967), overlain by the tongue of the Shawangunk (called Binnewater by both Gray, 1961, and Smith, 1967). About 2,000 feet farther west are rocks which we believe to be part of the High Falls Shale. See the section on stratigraphy for an understanding of these interpretations. The conclusions were based on tracing the various facies in the Shawangunk and Bloomsburg eastward from New Jersey.

Uppermost Shawangunk on left.

Bloomsburg Redbeds - Shawangunk contact
Contact between tongue of the Bloomsburg Redbeds and tongue of the Shawangunk on right.

High Falls shale dipping moderately northwest.

Shawangunk Mine
Shawangunk Mine high on northwest slope of Shawangunk Mountain to right.

View of Ellenville Arch straight ahead.

View of eroded Ellenville arch
View of eroded Ellenville arch producing flatirons in northwest limb of fold on right.

Granit Hotel to right
Granit Hotel to right and water tower at Minnewaska at top of Shawangunk.
2015 OHM: The Granit Hotel is now the Hudson Valley Resort and Spa. A proposal to construct a $750 million casino here in 2014 did not get approved.

Dark gray shales of Bakoven Shale on left.

D: PALEOGEOGRAPHY AND BRACHIOPOD PALEOECOLOGY OF THE ONONDAGA LIMESTONE IN EASTERN NEW YORK
RICHARD H. LINDEMANN
Saratoga Springs, New York 12866
HOWARD R. FELDMAN
Biology Department
Touro College
New York, New York 10036
During the three plus decades since Oliver (1954) formally divided the Middle Devonian Onondaga Limestone into its Edgecliff, Nedrow, Moorehouse and Seneca Members, the formation has been the focus of considerable attention. However, with the exception of subsurface investigations, research has concentrated on the formation as seen in outcrop between Buffalo and the Helderberg/Catskill area. Few geologists have ever examined the Onondaga south of its classic exposure in Leeds Gorge. As an arbitrary measure of this, we note that between 1962 and 1986 more than ten NYGSA field trips concentrated on the Onondaga while only one (Oliver, 1962) was sited in southeastern New York. As a result, stratigraphers and paleontologists alike tend to have a somewhat skewed impression of Onondaga paleogeography, a situation we hope this field trip will partially rectify.

D: PALEOGEOGRAPHY AND BRACHIOPOD PALEOECOLOGY OF THE ONONDAGA LIMESTONE IN EASTERN NEW YORK

STOP 1. Onondaga/Schoharie contact can be observed in an abandoned quarry
The trip begins in Wawarsing, New York, approximately 0.5 miles northeast of Vernooy Kill, 100 feet north of Route 209, on the property of Steve and Sue Caruso (Be sure to ask permission before entering outcrop area). The Onondaga/Schoharie contact can be observed in an abandoned quarry (AMNH [American Museum of Natural History] Locality 3151B; see Feldman, 1985) where the Edgecliff Member with characteristic large crinoids, trilobites and some Amplexiphyllum is accessible. The Edgecliff here is finer grained than in the Mid-Hudson Valley and represents the deepest part of the basin to shelf lithology we will see today.

STOP 2. Pull off on the west side of Route 209 (wide shoulder).
On the east side of the road note a transitional, deeper water facies, similar to that found at Locality 1, about 1 meter thick, with 0.5 meter of shallower water, "cleaner" Edgecliff Limestone. The fauna here consists of large crinoids, ?Amplexiphyllum, ?fenestrate bryozoans (weathered), and Syringopora. Note storm layers and a sharp break between two facies.

STOP 3. Here we are higher in the Edgecliff (about 4 meters thick).
The water was shallower and the brachiopods larger. Chondrites is evident here but not further southeast due to the fact that as the ramp deepened (to the southwest) the sediment became too "soupy" for tubelike or tunnel structures.

Entire Lower Devonian section
Note that along Route 199 we are passing through the entire Lower Devonian section, from the Thacher at the base, to the Schoharie, which underlies the Onondaga in this part of New York State

On W side of the road note complex thrust slices oblique to the section

Angular unconformity
Angular unconformity between the Wilbur Limestone Member of the Rosendale Formation (Late Silurian) on Normanskill (Austen Glen aspect) strata.

STOP 4. Note the gradational nature of the Onondaga/Schoharie contactPlacemark
Note the gradational nature of the Onondaga/Schoharie contact which is placed at the uppermost buff-weathering band. Ranging through the upper Schoharie into the lower Edgecliff are massive cyclostome bryozoans often encrusting (e.g. crinoids). Other faunal constituents here include brachiopods, particularly Atrypa "reticularis," and Fistulipora. The stratigraphy at this locality is complicated by faulting and repetition due to thrusting (note slickensides and slip-fiber sheets), thus making the Edgecliff seem to be thicker than it actually is. According to Marshak (1986) there are two major thrusts which display a relatively large stratigraphic throw along Route 9W. The upper one, now covered by the exit ramp, emplaces Esopus Formation on Onondaga Limestone while the lower one, exposed further to the north along the roadcut, emplaces Onondaga Limestone on Schoharie. The upper fault may be the continuation of the Fly Mountain Thrust. In general, there is an absence of favositids between here and Wawarsing, but north of here, especially in Leeds, they are abundant. Note the light-weathering chert.

Note Howard Johnson's on the right
If time permits we will pull into the parking lot and observe well-weathered blocks of Onondaga with silicified fossils [bryozoan bafflestone].

STOP 5: Large outcrop of Edgecliff
On the east side of Route 32 note a large outcrop of Edgecliff which shows, for the first time on this southwest-northeast transect, typical coarse-grained Edgecliff lithology. This is the southernmost exposure of the crinoidal biosparites which are so characteristic of the Edgecliff Member.

STOP 6: Chert seams and massive joints
DO NOT COLLECT AT THIS STOP; IT IS ON PRIVATE PROPERTY AND THE OWNERS DO NOT WANT ANY SPECIMENS OR BLOCKS REMOVED!
This outcrop, on the Kaaterskill (AMNH Locality 3137; see Feldman, 1985), known as Quatawichna-ach, takes its name from the Indian "place where all the water goes in a hole" referring to the chert seams and massive joints which take the water underground as it passes through the limestone (Chadwick, 1944). A stratigraphic placement of upper Moorehouse is indicated by [1] shale chips in the adjacent woods (probably Bakoven, since it outcrops a short way downstream], [2] dark-weathering chert, and [3] faunal similarity with upper Moorehouse strata from the Leeds area, specifically, Platyceras dumosum and Atrypa "reticularis." The fauna here is moderately to well-silicified probably due to the diagenetic action of percolating groundwater through the numerous joints. At this locality Feldman (1980) recognized a highly diverse Atrypa-Coelospira-Nucleospira Community containing the following morphotypes:
[1] Orthotetacids, Schuchertella (broad, flat)
[2] Nucleospira, Athyris (smooth spiriferids)
[3] Schizophoria (unequally biconvex)
[4] Atrypa (with frills)
There is a great similarity here with Lenz's (1976) Lower Lochkovian Howellella-Protathyris Community from the northern Canadian Cordillera in which he found similar faunal elements in an offshore position. A similarity is also evident to Copper's (1966) biotope of primitive, abundant Atrypidae in which variably sized atrypids occur with spiriferids and schizophorids in fine-grained sandstones, siltstones and shales with thin limestone interfingerings.

STOP 7. The only known exposure of the Bakoven/Onondaga contact
Descend steep embankment to Kaaterskill Creek where the only known exposure of the Bakoven/Onondaga exists. Whereas Oliver (1956) considered the Onondaga/Bakoven contact to represent a minor break in deposition we believe that the contact is a disconformity, albeit a minor one in this part of the state, representing a time period during which rapid crustal subsidence, to a shallow or proximal basin depth position below storm wave base, resulted in stratification of the water column and dysaerobic bottom conditions. We found evidence of a more substantial disconformity in central New York, near Syracuse, where the Union Springs Shale (lateral equivalent of the Bakoven) truncates westwardly dipping Seneca strata. At that contact there exists a substantial bone bed with reworked (?) crinoids and brachiopods, and current-sorted fish spines and/or teeth.

STOP 8 : Overlooking Catskill Creek
Overlooking Catskill Creek, to the east, note the Schoharie/Onondaga contact, to the east of which the Onondaga lies in an (overturned?) thrust-faulted syncline. If time permits we will examine the typical Edgecliff lithology at the waterfalls where trilobites, corals, and brachiopods are evident.

E: STRUCTURE AND STRATIGRAPHY OF THE NORMANSKILL GROUP (EARLY MEDIAL ORDOVICIAN) WEST OF THE HUDSON RIVER, TOWN OF LLOYD, ULSTER COUNTY, NEW YORK
ROBERT W. CUNNINGHAM
College at New Paltz
New Paltz, New York, 12561
The rocks of the Normanskill Group, formerly included in the Hudson River slates and shales are among the first studied rocks in North America. Notables such as W. W. Mather, Sir William Logan, and James Hall studied the rocks in the mid-Hudson area in the 1830's to 1860's. Because of the complex structure and repetitive stratigraphy of the Normanskill work has progressed slowly, with the most extensive and recent studies being done in the Albany, N.Y. and Quebec areas. In the Mid-Hudson, particularly in Ulster County, the Normanskill rocks have never been adequately mapped, despite extensive exposures along the Hudson River and in area highway and railroad cuts.
Recent fieldwork in the eastern part of the Town of Lloyd has resulted in several discoveries in the Normanskill Group. A relatively diverse shelly fauna has been found in a thick sequence of laminated strata tentatively dating these rocks as post-Austin Glen, but pre-Balmville in age, probably making these the youngest Normanskill rocks yet found. Outcroppings of lower Normanskill aspect (Mt. Merino Formation?), the first seen in this part of Ulster County, have been mapped around Blue Point. Four structural domains have been recognized on the basis of structural and lithologic criteria. Two of the domains apparently cross the Hudson River. Numerous folds and faults have been mapped, some of which show evidences of multiple deformation. Outcrops exposing thick stratigraphic sections have been measured for possible correlation, and excellent sedimentary structures noted in the Austin Glen Formation. Analysis of the data collected during this fieldwork can lead to a more comprehensive understanding of the age relations, sedimentology, stratigraphy, and styles of structural deformation.

E: STRUCTURE AND STRATIGRAPHY OF THE NORMANSKILL GROUP (EARLY MEDIAL ORDOVICIAN) WEST OF THE HUDSON RIVER, TOWN OF LLOYD, ULSTER COUNTY, NEW YORK

STOP 1. Near Mid-Hudson Bridge approach.
This road cut exposes rocks of middle to upper Austin Glen lithology, dipping about 45 degrees west. Thick beds of graywacke show massive bedding and thinner beds expose primary sedimentary structures such as flame structures, convoluted bedding, and cross-lamination. Cleavage dips less steeply than bedding indicating a possible downward facing structure. Looking south into the road cut for the Mid-Hudson Bridge, one can see the most complete section of Austin Glen strata yet measured (Krusansky, 1983, Manning, 1983). This section begins at a fault exposed near the final turn to the bridge, and continues with little interruption to the toll gate. It then continues in a railroad cut until it intersects the center of a N15°W trending syncline. This syncline plunges NE, and covers much of the area in domain 2 (figure 1). Strata from lower to upper Austin Glen is seen in this section.

STOP 2.Lower Austin Glen strata
This outcrop in the vicinity of Johnson Iorio Park contains lower Austin Glen strata. Both the north and south ends are quite deformed with a small reverse fault exposed at the north end, and an intense fault zone at the south end. Numerous graptolites have been found in rock fall near the Park entrance.

STOP 3 Blue Point.
This area consists largely of lower Normanskill strata - probably Mt. Merino Formation. This is the only known exposure of this rack type west of the Hudson River between Kingston and Newburgh. East of the Hudson it is more commonly exposed. This rock is a highly indurated, gray-green argillite with silty or cherty interbeds, and occasional pyrite layers. Gray to black shales are characteristic of the upper part of the formation. It is probably allochthonous with four thrust slices present locally, two on each side of the Hudson (figure 1). These outcrops constrict the river by about 30 per cent (pre-railroad width) accentuating the hardness of this material. The strata generally dip and young northwest except at the north end where it is overturned. It is highly sheared and folded making stratigraphy very difficult. Bedding can be traced by following the cherty or silty layers when the light is right. The southern part of the exposure is green argillite cored by a brown, dolomitic argillite forming an antiformal structure. The middle portion of the outcrop is primarily green argillite while the northern end contains sheared, gray to black shales known from the upper Mt. Merino. Graptolites are commonly found in these shales. To the northwest, the contact with the overlying Austin Glen Formation is probably at the north end of the outcrop where light gray, thin-bedded shales appear. A thin covered zone separates this strata from thick bedded graywackes with thin shales characteristic of the upper Austin Glen. This suggests a major fault trending southwest. The presence of other Mt. Merino outcrops directly across the river at Mine Point raises the question of whether the Hudson River is structurally controlled or whether it is a superposed stream. Circumstantial evidence here and to the north at Crum Elbow suggests that this is a superposed stream.

STOP 4.Typical upper Austin Glen lithology
This outcrop contains thick gray-wacke beds with thin shale interbeds typical of upper Austin Glen lithology. These beds dip northeast and are overturned. Cleavage dips gently southeast. The stream to the south may be a fault trace. If this is so, the fault may have reoriented this strata causing the shallow orientation of the cleavage.

STOP 5. Interbedded gray shales and graywackes
Interbedded gray shales and graywackes averaging 2 to 4 cm. in thickness with occasional calciferous or dolomitic, laminated siltstones comprise this outcrop. The rocks in the upper part of the outcrop dip northwest and may be separated from the lower part by a bedding plane fault. The lower strata dip generally northeast and are more deformed than those above. All strata appear to be overturned.

Here the same lithology is exposed as in Stop 3 except many broken sections of thick graywacke are present in the shales due to tectonic disturbance. These beds are overturned and dip about 25 degrees to the east. Bedding plane slickensides are numerous and are aligned approximately east west.

This section represents strata of middle to upper Austin Glen aspect with thin turbidites at the south end and thick graywackes at the north. These beds are highly deformed with the northern, more massive strata apparently dragged into folds along a fault at the north end. Another fault separates the thick graywackes from thin turbidites at the south end of the outcrop. The overall structure dips northeast with the beds dipping nearly 90 degrees at the south part of the section, decreasing to 40 degrees to the north, and then overturning and dipping 40 degrees southeast at the north end. This outcrop also contains curved tension gashes in the massive graywackes and disarticulated folds of thin graywacke in 'smeared' shales at the south. A thick graywacke surrounded by shales truncates abruptly near the south end. Just north of this outcrop, a tight drag fold of smaller dimensions is exposed.

Medium to thick bedded graywackes are exposed here which are upright, dipping 15 degrees northeast. Higher on the hill, these beds increase in dip and are likely to be separated from those of Stop 6 by a fault in a stream bed.

This outcrop contains black shales with fragmented sandstone layers enrolled in the shales. This outcrop is highly disturbed. Relatively flat-lying beds appears to pin almost vertical graywackes to the hill, while thick shales show pinch and swell structure between graywacke layers. Tension gashes and "riedel shears" can be seen in this convoluted section.

This exposure of lower Austin Glen contains 1 to 2 cm. thick graywackes and shales. Pyritic graptolites can be found here. Tight folds have formed in this sheared strata with shale enveloped sandstone fragments indicating the degree of deformation. Strata dip northeast at the south end and northwest at the north end, while the cleavage dips east-southeast at a low angle.

This 1500 foot (460 m.) long section consists of lower to middle Austin Glen lithology south of the Poughkeepsie Railroad bridge, and upper Austin Glen north of the bridge. This area offers a good stratigraphic section to compare to that in the Mid-Hudson bridge approach (stop 1), and that seen in the railroad cut north of Crum Elbow (stop 27). Beds 1 to 4 cm. thick of alternating graywackes and shales predominate in the southern strata with well developed (ignore the graffiti) reclining, parasitic folds. These give way to thicker graywackes and shales just south of the bridge. Graptolites were found where a cut was made for cables which cross the Hudson River. Thick beds of graywacke dominate north of the bridge abutment. At the south end of the outcrop the beds dip northeast at 40 degrees, increasing to 53 degrees north of the bridge. This is part of the synclinal structure seen at Stop 1.

Highland Landing. This stop consists of middle to upper Austin Glen strata dipping N65E. A small reverse fault cuts this outcrop and a thrust runs along the upper part. Turbidites averaging 10 cm. in thickness dominate the southern half of this outcrop, while thick turbidites with thin shales constitute the northern part beds. Flute casts are visible an the undersides of some beds.

A shear zone formed in a failed fold hinge occurs at the south end of this stop. Rounded sandstone blocks enrolled in a shale matrix give good evidence of the shear couple at work here. This commonly happens in the hinges of the recumbent folds found in this area when the rock is stretched beyond its yield point dragging fragments of more competent strata into dismembered folds surrounded by shale. The rocks dip steeply northwest at the south end of the outcrop, but flatten considerably to the north. This is apparently middle Austin Glen lithology.

These thick graywackes with thin shale interbeds characteristic of the upper Austin Glen are overturned, dipping 85 degrees northeast. Convoluted beds and rill patterns show the effects of dewatering of the clay layers due to loading. Note the foliated shale clinging to the bottom of some graywacke beds. Sigmoidal tension gashes show orientation of compressive forces, although block rotation cannot be inferred here. A tight fold seen at the north end leads into another shear zone with fragmented graywackes in a shale matrix.

Here, middle to upper Austin Glen with turbidite beds vary from 3 to 7 m. thick with thin turbidites overlying them. Beds are steeply dipping (NW) with a northeast strike. Sedimentary convoluted beds can be seen at the south end.

This is a steeply dipping limb of a synclinal fold which plunges gently north-northwest. Complementary sets of tension gashes indicates direction of maximum compression. Sedimentary structures include rilled surfaces, cross-cutting tool marks, and to the north a 100 foot long by 60 foot (30 m. x 20 m.) high bed under-surface with large flute casts of bidirectional orientation. Shales are altered in color from black to orange, possibly due to incipient metamorphism. It is unfortunate that this as well as many other important geologic features have been painted over in the name of school spirit, young love, or personal identity. North of this outcrop is a tidal pool indicating the pre-railroad (1878) shoreline. Before the railroads were constructed the Hudson River shoreline was considerably more sinuous.

This outcrop contains more sedimentary structures such as convoluted bedding, parallel, horizontal tool marks and, to the north, curved tool marks. Structural indicators are fibrous calcite slickensides, and tension gashes whose sigma one direction appears to be perpendicular to that of the last stop. Here again, orange weathering shales are seen.

STOP 18. House on river, quarry.
This quarry supplied graywacke curbstones for New York City. Near the river these middle to upper Austin Glen graywackes and brown weathering gray shales are quite deformed. Overturned shales are pressed against thick upright turbidites which dip 40 to 75 degrees southwest. In the quarry the beds dip 60 to 70 degrees southeast.

This outcrop contains varying lithologies with thick graywackes underlain and overlain by thin turbidites. Similar sequences are seen at several other outcrops. The south end of this section is a shear zone with folded, dolomitic graywackes enrolled in a shale matrix. Toward the north a thick graywacke is encountered, truncated by a reverse fault forcing thin turbidites around it. Immediately beyond, a thick section of 1 to 3 cm. thick graywackes and shales are displaced by faults every few feet.

Thin turbidites form an antiformal structure. Deformation is similar in style to Stop 19. Here, brittle deformation has resulted in at least 4 steeply dipping, cross-cutting faults. These faults separate the strata into zones with different orientations. At the south end the rocks dip 70 degrees to the east. In the next zone they dip about 30 degrees northeast, then 40 degrees northwest. They then change to 5 degrees to the west, and finally at the north end dip 40 degrees southwest and seem to dissect a north plunging anticline. Numerous tension gashes are exposed at the south end of the structure.

This outcrop begins in thin gray shales and laminated siltstones striking slightly west of north and dipping 65 degrees northeast. Small scale folds are well developed as are joint sets. To the north thick graywackes predominate. Here the beds have rotated to N35E, exhibiting tension gashes. North of the outcrop is a broken zone probably representing a fault.

Following a shear zone at the south end, the cut exposes thick graywackes with dolomitic, laminated turbidites. These beds strike S80W, and dip 35 degrees northwest. This is the first of two outcrops with this anomalous orientation. These rocks probably form a thrust slice separate from the surrounding rocks. This is probably an upper Austin Glen lithology.

Here is a continuation of the lithology in Stop 22. Thick, massive graywackes contain many rip-up clasts of foliated shale. At the north end of the outcrop laminated, dolomitic sandstones underlie the thick graywacke beds. These rocks strike S85E and dip 23 degrees NE.

These beds are oriented N60E to N40E dipping 40 to 67 degrees NW. This assemblage of rocks is dominated by thin turbidites with 10 to 15 cm. thick shale interbeds. This cut shows very good cleavage development with refraction of cleavage into the graywackes. Cleavage is oriented at N42E by 85 degrees SE. At the north end these turbidites dive under thick graywackes which lay at N85W, dipping 55 degrees, increasing to 90 degrees at the north end.

This outcrop consists af a 7 m. band af (2 to 30 cm.) turbidites underlain and overlain by graywackes up to 5 m. thick in a section totalling 40 m. (Hayden, 1986). Insoluble residue studies of some af these shales have revealed up to 55 per cent CaCO3 by weight (Miller, 1986). This outcrop is extremely similar in lithology and cleavage orientation to those in an outcrop located across the Hudson River the Roosevelt estate, suggesting a continuation of structure across the river. The strata of the outcrop dip southeast at 15 degrees at the south end, flattens in the middle, then steepen to 25 degrees SE at the north end.

STOP 26. Crum Elbow.
Here the lithology contains middle Austin Glen with 2 to 15 cm. thick turbidites and occasional thick graywacke beds. Cleavage in this outcrop is N35E dipping 76 SE. Several small thrust faults cause the bedding to splay in several directions at the center of the outcrop. Toward the north end of the outcrop is a kink fold whose axis trends N35E, plunging 73 degrees SE. North of this are lower Austin Glen strata striking N25E, dipping 35 degrees SE. The open valley and stream to the north probably indicate a fault zone.

This road cut contains the best stratigraphic section of lower Austin Glen north of Highland. A fault zone at the south end of the cut is traceable for a couple miles to the south-southeast, and forms the boundary between domains 3 and 4 (figure 1). The north edge of this fault zone contains small drag folds along the last two faults in the fault zone. North of here the strata are overturned, dipping steeply to the east. Thin (1 to 3 cm), turbidites dominate the youngest part of the section, thick graywackes are common in the middle, and thin turbidites again dominate the north end with a few thick graywackes interspersed. Where outcrop on the east side of the tracks ends, another fault terminates the stratigraphic section. North of this are more complexly deformed rocks of the same type and age.

This cut begins at Mile Marker 76, continues for about 1000 feet (300 m.) and contains repeating, sometimes overturned sections of lower Austin Glen strata. These rocks strike about N25E dipping 74 degrees SE. These turbidites usually are 2 to 15 cm. thick. At the north end the graywackes and shales are highly disturbed with massive sigmoidal tension gashes, and en echelon phacoidal fragments of sandstone surrounded by a shale matrix. The stream is probably another fault trace.

This section is complexly deformed and folds plunge steeply northeast. Beds are alternately upright and overturned. At the south end the bedding is overturned, and forms an undulating, curved surface. Tension gashes are vertically oriented, with a number of en echelon sets exposed. In the middle of the section the beds are generally upright. Boudined calcite slickensides are exposed about in gray shale 12 feet up from the road. A massive tension gash oriented horizontally is over twenty feet long and may bend around the rock mass which it envelopes. At least three generations of vein filling can be identified including milky quartz, white calcite, and late clear calcite. The beds at the north end of this outcrop are overturned and are composed of gray shale and thick graywacke. Flattened flute casts are oriented in a near vertical position.

Here the uppermost Normanskill strata are seen for the first time. These are laminated siltstones and shales (usually less than one cm.) with occasional thicker graywacke layers. Here the beds are overturned, striking N8W and dipping 57 degrees NE. At the south end thick tension gashes are seen in the graywackes. Further north curvi-planar surfaces cut by joint sets are seen. These rocks seem almost 'reptilian' in appearance (curvi-planar with 'scales'). To the north, a thrust fault trace is exposed plunging moderately north. Massive tension gashes are exposed below, and up the cliff face they form large curving cavities. At the north end of the outcrop on the footwall of the fault the rocks are less deformed, although they still exhibit good jointing.

These rocks at Mile Marker 77 contain the same lithology as those in Stop 30; laminated siltstones and phyllitic shales showing good jointing. These beds are oriented N8E and dip 72 degrees SE. The strata, and most of those to the north and west continue for miles striking a few degrees east or west of north and dipping-steeply east for the most part.

These laminated siltstones, sandstones, and shales belong to the uppermost Normanskill strata. Bedding is variable as this location is near an inferred east-west fault zone. The Esopus fault lies about 3000 feet west of here. Fossil brachiopods are found in the disturbed rock, but the exotic trilobites found further south have not been seen here.

STOP 33. Railroad cut through north end of Illinois Mt.
Here the Esopus fault lies to the south with rocks of the upper Ordovician Quassaic Group sitting to the west. These rocks form most of Illinois Mountain, and then bending eastward to form the hill to the northeast. The unnamed rocks of uppermost Normanskill are laminated sandstones, siltstones, and shales. They are seen on the east end of Grand Avenue and along a power line running along the east side of Illinois Mountain. Numerous small brachiopods are found in these rocks. In the railroad cut rocks of the Slabsides Formation of the Quassaic Group are exposed. These are steeply dipping, medium to thick graywackes with thin shale interbeds. Shale clasts and limestone pebbles are much more common than in the Normanskill strata. Large strophomenid brachiopods are often seen on the bottoms of sandstone beds.

F: GEOLOGY ACROSS THE GREAT VALLEY:FROM THE SHAWANGUNKS TO THE HUDSON HIGHLANDS
Lawrence E. O'Brien
Orange County Community College
Middletown, New York 10940
Orange County is a region of diverse geology, with bedrock ranging in age from Precambrian to Devonian, with structures ranging from klippe and overturned folds to relatively flat-lying strata, with geomorphic features varying from bedrock to glacial, and with fossils varying from the Otisville Eurypterid to the Sugarloaf Mastodon. Despite this diversity the county has not (with the exception of the Hudson Highland area) been the site of a great deal of geologic study.
On this field trip we will begin with the least deformed Silurian Bloomsburg and Shawangunk formations on the west side of the county near Port Jervis and traverse southeastward through succeedingly older and more deformed rocks of Ordovician and Cambrian age to the 1.1 billion year old Precambrian rocks of the Hudson Highlands following routes I-84 and 9W. We will not have time to see some of the interesting rocks and structures farther south along the New jersey border but these have been discussed by Offield (1967) and Jaffe and Jaffe (1973).

F: GEOLOGY ACROSS THE GREAT VALLEY:FROM THE SHAWANGUNKS TO THE HUDSON HIGHLANDS

Lower Devonian Esopus formation
The cliff behind you is the sands and shales Lower Devonian Esopus formation (sometimes called the Esopus Grits in this area).

Trilobite Ridge - Lower Devonian Glenerie Limestone
Between mile markers 1 and 2 the ridge visible to the left (north) side of the interstate is Trilobite Ridge, a famous collecting locality composed of the Lower Devonian Glenerie Limestone.

Silurian Bloomsburg Red Beds.
The redbeds on the right are the sands and shales of the Silurian Bloomsburg Red Beds.

STOP 1. Stop at the parking area.
The view northwest from this overlook is across the valley of the Neversink River which flows in a valley composed of Devonian carbonates (the Onondaga Limestone) lying between the Shawangunk Ridge (to the right) composed of middle Silurian clastics and Allegheny Front (across the valley), composed of Devonian clastic strata of the Hamilton Group. The confluence of the Delaware and Neversink Rivers is to the left in Port Jervis. The Delaware River can be seen to the southwest as it flows along the west side of the Shawangunk Ridge.
The rock cut to the west of this parking area is in the redbeds of the Silurian Bloomsburg Redbeds (or High Falls Formation) which strike approximately N.40°E and dip 25-30° NW at this location. They consist of fine red sands, silts and shales, often with mud cracks and gray reduction spots, interbedded with coarse, gray-green sands showing trough crossbedding. There are noticeable carbonate grains in the coarse cross-bedded sands. The Bloomsburg, which is conformable with the underlying Shawangunk conglomerate (stop 2), is inferred to be an alluvial deposit with the coarse beds reflecting channel deposits and the finer redbeds being floodplain deposits. It was shed westward from the mountains of the Taconic Orogeny, which existed to the east, into a sea which existed to the west. This formation grades downward into the basal Shawangunk conglomerate which unconformably overlies earlier (pre-Taconic Orogeny) sediments.
Things to look for at this stop include:
1. Good cross-bedding in the coarse gray sands.
2. Carbonate grains in the coarse gray sands (what is their origin?).
3. Gray reduction spots in the redbeds. Some vertical reduction spots may follow burrows.
4. Pebbles of fine red silts/shales in the coarse gray sands.
5. Mud cracks in the finer sediments.
6. Invertebrate tracks. I have seen these at one other locality, but not here.

STOP 2: Angular unconformity between Shawangunk and Martinsburg
This location is at the angular unconformity below the middle Silurian Shawangunk formation and the underlying mid-Ordovician Martinsburg formation. At this locality the angular discordance is very slight which is the same as I have seen at other exposures of the unconformity in Orange County.
The basal Shawangunk is a quartz-pebble conglomerate with a sandy matrix which grades upward into a coarse sand with fewer and smaller pebbles. Some feldspar fragments are visible in the upper coarse sand areas. The limonite stain on the Shawangunk results from oxidation of pyrite which may be seen as minute grains in the matrix of the conglomerate. The Shawangunk has been interpreted as a beach deposit (Fink and Schuberth, 1962) and as a braided stream deposit in a complex transitional marine-continental environment (Epstein and Epstein, 1972).
Between the Shawangunk and the Martinsburg is a brown clay layer which may be seen in other exposures of the unconformity in this area. Waines (Waines, Shyer and Rutstein, 1983) has speculated on the origin of this layer and has called it a paleosol, although there are several other plausible origins. The other possibilities will be discussed on the outcrop.
Walking around the outcrop to the right (west) you may note some glacial smoothing of the dip slope and along a trench behind the outcrop you can see an exposure of slickensides on a fault plane which strikes N 60° W and dips about 65°NE. The slickensides plunge about N 40° W at 30°. According to Fink and Schuberth (1962) tear faults like this are more common farther south in New Jersey. There are also several quartz veins on the dip slope and they strike N 70°±10°W.
Things to look for at this stop include:
1. The clay layer at the unconformity.
2. Pyrite grains in the Shawangunk.
3. Slickensides on the tear fault.
4. Glacial smoothing and quartz veins on the dip slope.
5. Variation in quartz pebble size and quantity. An interesting question is what is the source of the quartz pebbles since they are not common in the underlying Martinsburg.

Drainage interruption due to the highway.
The swamp in the median and to the right (south) is an example of drainage interruption due to the highway. A beaver lodge is sometimes visible in this swamp.

STOP 3: Approximate mile marker location 9.8
This is the first of four stops in the mid-Ordovician Martinsburg formation which will emphasize different types of structural deformation and sedimentary features.
At this location you can see more or less horizontal beds in the Martinsburg at each side of a section of almost vertical beds. The deformed structure is approximately 225 feet wide and varies from N 25° E, dip 82° SE on the south side of the highway to N 15 E and vertical on the north side. This seemingly isolated segment of almost vertical beds could be several things: an isoclinally folded anticline or syncline, a monocline downthrown to the northwest or to the southeast, a rotated fault block or possibly something else. The graywacke beds in the Martinsburg often show graded bedding so it is possible to determine the original bed tops in the vertical section. It appears the bed tops are all facing the northwest (thus eliminating the isoclinal fold possibility) and they show an obvious upward curvature at the west end of the tilted section. This suggests a monoclinal flexure downthrown to the northwest, but similar indications of folding at the southeast end of the tilted section are not apparent. I suspect the monocline has been cut off by faulting at the southeast end but the evidence is not clear.
A second question is when did the deformation occur. Conventional thought would relate it to the Taconic Orogeny of late Ordovician time, but Epstein and Lyttle (1986), based on work done in 15 areas along the Taconic Unconformity from Pennsylvania to New York, suggested that post-Taconic faulting had cut both the Martinsburg and the overlying Shawangunk. Compare this style of deformation with the other styles of deformation you will see in the Martinsburg at stops 4 and 6 and ask yourself whether this high-angle faulting might represent a different episode of faulting.
Things to look for at this stop include:
1. Grading in the graywacke beds.
2. Slickensides on the bedding planes of the vertical beds. Try to determine sense of motion of the slip.
3. Evidence for folding/faulting at the east end of the deformed section.

STOP 4. [Approximate mile marker location 11.3]
This cut is on the north side of the west-bound land of I-84 [Note: During the field conference this will be the first stop so that we will not have to cross the highway].
At this location the Martinsburg shows a typical "suddenness" of intense deformation. Beneath the overpass and to the east of the overpass the beds are relatively flat and seemingly undisturbed, but about 130 feet west of the overpass the bedding is sharply deformed by an overturned anticlinal fold which has been cut by a thrust fault. This thrust fault and associated drag folding extends 140 feet further west where it curves upward to the top of the road cut in a characteristic listric-fault fashion. The fault and associated drag folds strike about N.40°E and dip SE. Be sure to compare this style of deformation, which I consider to be unquestionably Taconic, with the style of deformation you see at Stops 3 and 6 in the Martinsburg.
This is a good location to examine slaty cleavage in the shale layers. It strikes N.40-60°E and dips 25° SE, but does not penetrate the graywacke layers. This is a good stop to show students that slaty cleavage is a pressure phenomena unrelated to primary bedding. The sketch at the left extends west from the overpass to the west end of the cut.
1. Slaty cleavage between the graywackes.
2. Synclines and overturned anticlines produced by drag folding.
3. The listric thrust fault. Try to estimate the amount of offset if you can find a suitable marker.

Underpass with wind generator to left (north).

STOP 5. Recent (1968?) deformation in the Martinsburg
This is a brief stop to examine recent (1968?) deformation in the Martinsburg. Notice the drill holes on the south side of the highway. They have been offset by slippage in an up-dip direction to the northwest. I was told by Cliff Lloyd, who brought this site to my attention, that most of this deformation took place shortly after completion of the highway and that for a time the highway department had been quite concerned about it. I have stopped here a number of times since 1973 and there has been no noticeable change since that time. You can see that there are several slippage planes, each deformed by a thrusting motion, probably related to stress relief following excavation of the road cut. For a recent article on this phenomena with a list of reference see Bell (1985). He lists references to other such features in the Appalachians.
Across the road you can see another thrust fault (Taconic) which strikes N20°E and dips 35° SE.
1. Amount of offset on the recent faults.
2. Drag-folding on the thrust fault.

Bridge over the Wallkill River.

Gravel flows on the right (south) side of the highway.
The gravel, intended to prevent slumping of the underlying material, has itself flowed downslope. These flows have noticeably enlarged over the past few years. Do you think the motion is partly within the gravel, or is it merely slipping over the substrate? Compare this with the cuts at 34.0 and 35.3.

STOP 6. [Approximate mile marker location 31.5]
This long road cut shows a number of interesting features, both structural and sedimentological, in the Martinsburg formation. The diagram at the left extends along the cut on the south side of the highway westward from the overpass for 500 feet.
Structure: On the south side of the highway there are a number of faults which cut the strata. Examination of the drag folds and the offset of the strata at 200 feet show that these are mainly normal faults. This deformation does not seem to match the thrusting which was evident at stops 4 and 5. While it would be nice to see a normal fault offsetting a thrust fault, I nevertheless believe this is a post-Taconic period of faulting. Whether these faults, downthrown to the southeast, are related to the deformation at stop 3 (downthrown to the northwest) I can't tell.
North of the highway and east of the overpass are a pair of adjacent anticlines offset by a fault, and plunging in opposite directions. This in an interesting spot to have students test their powers of observation.
Sediments: The Martinsburg is a classic flysch deposit with the graywackes of the Martinsburg being classic turbidites (turbidity current deposits) (McBride, 1962). Turbidites are considered to have an "ideal" sequence of structures which has been called a Bouma cycle after the Dutch sedimentologist who described them in 1962. A complete Bouma cycle consists of the five divisions shown in the diagram below. Often some of the divisions are missing but the ones that are present are always in the same order. Proximal deposits (near their origin point) are more likely to have a significant A division whereas more distal deposits may consist only of divisions C, D, and E. Examine the graywacke beds closely and try to identify the various divisions of the Bouma cycle. Are these proximal or distal deposits?
1. Faults. What type? Amount of offset.
2. Drag folds along faults.
3. Oppositely plunging anticlines on north side of the highway.
4. Bouma cycles in the graywackes. Identify each division present. Are the turbidites proximal or distal?

Another long outcrop of Martinsburg.

Slumping in road cut to right.
This cut was given no special engineering protection to prevent mass wasting. Compare this with the cuts at 27.0 and 35.3.

Gravel drainage zone around top of road cut to right.
Highway engineers apparently decided to intercept the water which would percolate down the slope and cause mass wasting and drain the water off to the side. The lack of slumping or flow compared to cuts at 27.0 and 33.0 suggests it was effective.

STOP 7. This is one of perhaps 14 small (?) klippe
This is one of perhaps 14 small (?) klippe, or allochthonous blocks of Precambrian Hudson Highlands material which was thrust northwestward during the Taconic Orogeny and then isolated from the parent mass by later erosion (other interpretations have been made but this is the one I like).
Toward the east end of the road cut you can see the Cambrian age Poughquag Quartzite, which at this location is noticeably conglomeratic. The pebbles are mainly quartz and the matrix contains substantial amounts of pyrite. Oxidation of the pyrite has caused the pervasive limonite staining of the rock. Toward the western end of the cut the Poughquag overlies Precambrian granitic gneisses in a classic nonconformity. The gneisses have been severely weathered and are almost unrecognizable at the first casual glance. The attitude of the unconformity shows that the Poughquag extended above the level of the cut on the north side of the highway and has been eroded away so that only gneissic material is exposed. This transgressive Cambrian sand marks the inundation of the continent following rifting of the continent after the Precambrian Grenville Orogeny. It probably represents a beach environment.
The outcrop across the entrance ramp to the northwest (onto I -84 west) is Martinsburg, so the basal fault below this thrust block must be located between the two cuts north of the highway, however I have never seen reference to it by anyone who noted it during the building of the highway.
1. The non-conformity at the base of the Poughquag.
2. The granitic gneiss below the unconformity.
3. Variations in pebble content in the Poughquag.
4. Evidence for faulting in the Poughquag.
5. Pyrite in the matrix of the Poughquag.

Road cut though Cambro-Ordovician age Wappinger Group Dolomites.
These represent a stable shelf environment which existed here following the transgression of the Poughquag. They persisted until the downwarping of the continental margin began during the subduction and closing of Iapetus which preceded the Taconic Orogeny. They are overlain by the flysch deposits of the Martinsburg which are subduction-related (Isachsen, 1980). For additional information on these carbonates see Friedman (1975).

Start of oil tank area for Port of Newburgh on the left.
Several of the homeowners in the area complained of devaluation of their property as this tank farm expanded. Would you agree?

Bridge over Moodna Creek.

The hill in front of you marks the beginning of the Hudson Highlands.
The road leaves the valley of Martinsburg sediments, crosses the northwest border fault of the Highlands thrust block and starts up the Precambrian gneissic material. The first outcrop is visible on the left shortly after you start up the hill.

STOP 8: Overlook at Storm King.
[Note: During the field conference this will follow stop 9 so that we will be able to park at the overlook.]
This cut is an excellent exposure of the Storm King granite gneiss, at this location a two-feldspar, hornblende granite gneiss. The gneissic structure is shown by lineation of the amphiboles and a similar elongation of the quartz (Lowe, 1958. indicates there is "no clearly preferred space-lattice orientation" of the quartz). There are a number of pegmatitic zones in the granite and these have a similar mineralogy to the surrounding finer-grained areas. The pegmatite zones sometimes follow the strike of the lineation in the gneiss and at times cut across the lineation suggesting they are either late-phase crystallization or later remobilization of the material. The Storm King was first thought to be a late intrusion into the gneisses (Lowe, 1958) but is now suggested to be an early Grenville intrusion (Helenek and Mose, 1984, give a date of 1140 m.y.).
The overlook to the east provides an impressive view over the Hudson River.
1. Large hornblende crystals in the pegmatitic zones.
2. Orientation of the pegmatitic zones relative to the lineation of the gneiss.
3. Nature of the lineation.
4. A cross-cutting, epidote-filled fracture.
5. View from the overlook.

The proposed Storm King pumped storage reservoir site is on the right (west) side of the highway.

STOP 9. Other gneisses of Hudson Highlands and a nice dike
This cut exposes some of the "other" gneisses of the Hudson Highlands, and one of the best dikes you could ask for.
The gneisses are quite varied in composition and in several places show coarse-grained remobilized zones. Garnets are abundant locally but they are usually fractured and are difficult to remove from the gneiss. You can see how distinct the Storm King gneiss is from these other gneisses.
The dike, which is visible on both sides of the road cut, strikes across the road cut at N47°E and dips approximately 70°NW but it curves markedly on the right (east) side of the cut. Close examination of the dike shows it to be mafic (dioritic to gabbroic) with accessory pyrite. There are excellent chilled margins with knife-edge sharp contacts with the country rock (best seen on the east side of the cut). There are also several apophyses (tongues) extending into the country rock. About 2 meters above road level on the east side of the cut, you can see two small light-colored intrusions into the chilled margin of the dike. These obviously came from the dike's still molten interior and thus are auto-intrusions, one of the clearest examples I have ever seen.
Facing the dike on the east side of the cut, you should notice the dark (mafic) band about 7 cm wide which parallels the right contact inside the chill margin. This mafic zone does not exist along the left contact but there is visible a zone parallel to the contact and inside the chilled margin characterized by coarse blebs of light and dark minerals. Similar zones are visible in the dike on the other side of the cut but they are harder to see because of groundwater which normally drains along the margins on that side. These dissimilar zones present a problem. Why is the dike not symmetrical? I am tempted to believe the mafic zone on the right is an example of crystal settling of the mafics and the blebby zone on the left represents the last stages of crystallization of the dike, but if this is true it would seem to require a significant upward rotation of the dike since its crystallization. I have not seen or read of a similar feature on other dikes in the area (Mack, 1962; Ratcliffe et al, 1983; and others). Differential weathering is noticeable at the top of the dike where the spheroidal weathering of the mafic dike is in sharp contrast to the minimal weathering of the surrounding gneisses.
The engineering techniques used to minimize the hazard of falling rocks are also worth mentioning. On the west side of the cut you can see rock bolts, a ledge and a fence (chicken-wire conglomerate). What you can't see is that they have replaced the guard rail on that side 3 times in the past 15 years and still there are dents visible on top of the rail. The fault zone visible above the ledge was the source of a major fall several years ago. A fracture pattern on that side of the cut dips into the cut so it is virtually impossible to totally prevent rock falls here.
1. Intrusive features such as chill margins on the dike, auto-intrusions in the dike, and apophyses from the dike.
2. Mafic and blebby zones in the dike.
3. Spheroidal weathering at the top of the dike.
4. Remobilized zones and garnets in the gneisses.
5. Evidence of falling rocks and engineering techniques to prevent them.

G: KARST AND STREAM CONSIDERATIONS IN THE ENVIRONMENTAL GEOLOGY OF THE MIDDLE RONDOUT AND ESOPUS VALLEYS, ULSTER COUNTY, NEW YORK
Lawrence R. Matson
Department of Physical Science/Geology
Ulster County Community College
Stone Ridge, New York 12484
The geology of the middle Rondout and Esopus Valleys is as rich and varied as is the story of the struggle of the early colonial Dutch, French and English settlers of this region. The area has remained essentially rural in character until recently, but with the relative nearness of the nation's largest metropolis in the time of rapid transportation and high-tech employment the region's land is quickly becoming developed.
Soils in these valleys are on bedrock of carbonates topped by thick deposits of till, modern alluvium and post-glacial lake bottom deposits. These valleys are well known for abundant harvests of sweet corn and apple production. Any acid precipitation is apparently neutralized by the carbonate character of the bedrock and the alkalinity of the streams that flow across them since no noticeable effects that occurred in these valleys. But the increase of population is coupled with a greater need for groundwater construction resources such as sand and gravel, and additional land fill sites for waste disposal. Land development has occurred here, as it has in many other areas, with little forethought and planning for environmental consequences. This field trip is a look at some factors that should be considered here and in other areas with a similar projected development of the land.
Figure 1 is a location map for this field trip. The trip can be taken with 11 stops or as either of its parts. The first part, trip G-I (stops 1-6) is a study of the environmental geology and hazards associated with Karst features of the Stone Ridge area; and the second part, trip G-II (stops 7-11) is a study of the environmental geology of the Esopus Creek Valley and some factors that may be at least partially responsible for apparently increased stream flooding and the resulting publicly voiced concern of local residents.
The middle Rondout and Esopus Valleys are enclosed by clastic rocks of the Shawangunk Mountains to the southeast and the Catskill Mountains to the West. A more complete discussion of the bedrock geology of this "classic" area has been recently described by Lindemann and Waines (1987), and a postulated stratigraphic column of most of the formations of the valley is given in Figure 2. The Onondaga Formation is located stratigraphically 225-420 feet higher in the column than the Glenerie Formation. The basal Onondaga Formation beds are coarse-grained limestones containing abundant corals and large crinoid columnals, while the upper beds are fine-grained limestones containing dark-gray to black chert and bryozoa and brachiopod fauna.
Karst features of the Stone Ridge, N.Y. area involve principally the Onondaga, Becraft and Rondout Formations, all quite pure limestones subject to dissolution. These units have been mined in open pits and shafts for the manufacture of natural and portland cement and for use as construction aggregate. A small solution cavity swallowing an intermittent stream is located in the Onondaga Limestone near the intersection of Route 9W and Route 199 near Kingston, N.Y. and outside of this field trip area. Pre-Wisconsinan near-surface weathering may have led to the development of solution features along joint planes in the carbonates of these valleys.
Concurrent with the forced closings of present landfills throughout the region, community leaders are faced with the difficult tasks of locating economically feasible waste disposal sites while also protecting their citizens, present and future. In order to locate and determine sites that are suitable for safe waste disposal, knowledge of site geology must be included. Early input by geologists and hydrogeologists may quickly rule out some areas before costly engineering and construction is performed. Conversely early study by geologists and hydrogeologists may affirm the inherent suitability of a site and allow progress in the difficult task of landfill selection. Important in the study of landfill site selection, in the proper management of sand, gravel and water resources and in stream flood control is an appreciation of the surficial deposits. The surficial deposits of the study area include lodgement till, modern alluvium and kames, (figure 3).
Figure 4 is the location map for a proposed landfill site near Rest Plaus Road in the Town of Marbletown. The geology and hydrology of the site and nearby areas proved to be more complex than could be estimated from published geologic maps and a brief study would indicate. Field trip part G-I examines the evidence that geological and hydrological data should be gathered and analyzed early in landfill site selection.
Field trip part G-II is a study of stream conditions that have become, at least in the eyes of the public, an increasing threat from flooding. The Esopus Creek has, however changed its course several times in the pre-history and perhaps early history of the area. With this fact in mind, present land-use practices may be evaluated less harshly than may immediately be apparent. Nevertheless, certain land-use practices, such as mining or other stream disturbances may upset a balance and increase existing environmental problems. We will examine the possible or probable effects of mining, agriculture, and residential and commercial development in the Esopus Creek floodplain.

G: KARST AND STREAM CONSIDERATIONS IN THE ENVIRONMENTAL GEOLOGY OF THE MIDDLE RONDOUT AND ESOPUS VALLEYS, ULSTER COUNTY, NEW YORK

Oxbow on right (west), and Stop 10.

Onondaga Limestone exposed along highway for next 1.5 miles.

Meander of Esopus Creek on right (west).

Onondaga Limestone (old quarry?) on right (west)

STOP 1. Enlarging Sinkhole
This sinkhole was first noted in the mid- 1970's. At that time, it was approximately 5 feet in diameter and provided a convenient drain for the then-producing grapevines nearby. In ten years, it has enlarged to its present diameter of about 20 feet, with two well-developed channels leading to it. A drain next to the highway leads to a storage basin that overflows with each heavy rain. CAUTION PLEASE: the storage basin cover is a lightweight steel plate and is usually lifted off the basin entrance by the force of the overflowing water; the opening is a danger to anyone walking through the brush along this road.
Another small sink has developed next to the foundation of the rear of the two-century-old house immediately north of this stop. Please respect private property and do not enter without permission. An additional sink is located east of the rear lawn, and some subsidence is in evidence on the front and side lawns.
The former owner of the property on the west side of the highway wished to construct a small pond on the property. He excavated soil and lined it with clay as he was instructed by personnel with the State Department of Environmental Conservation, and watched it fill with rain water. He was quite perturbed to see the water go "down the drain." In the center of the dry basin was a hole about one foot in diameter which he sealed with cement. The man-made basin stays dry and the present landowners are evidently trying to fill it with debris.
The cause of the sinkhole development here is evidently the collapse of a cave or cave system within the Onondaga Limestone during a lowering of the local water table. When the water level dropped, the cave roof was unsupported and collapsed. The condition is accelerated by the entrance of surface water that can cause more solution of the carbonate bedrock.
In the mid-1970's, a company located about one mile to the north of this site was using water drawn from several drilled wells. The company reportedly had a need for a dependable and plentiful supply of water and were concerned that the water level in its wells had dropped more than 40 feet in three or four years. The company wanted to know where it should drill for more water. At least one neighbor was concerned that the company's drilling for more water was causing his household well to be contaminated with silt and clays. The company was advised to obtain its water from the west side of the highway from tills and alluvial sediments in the Esopus Valley. This "solution" has evidently ended for the present the company's water supply problems.
The cause for the lowering of the local water table is difficult to determine. The construction of the wider highway may have restricted important recharge locally (Egernier, personal communication). Ulster County Community College with large, impermeable parking lots and increased commercial development locally may all be withdrawing much water and preventing recharge that could result in a lowering of the water table. There has been a significant increase in the number of homes built nearby, and all have drilled wells with cones of depression that may cause a lowered water table. The temperature-precipitation conditions may have changed to decrease the ground water recharge. A stream, local excavation, or roadcut nearby may have intersected a cave or fracture system that is now flowing as a spring. Of course, the lowering may be a natural event producing a sinkhole that should be considered normal in a carbonate bedrock located in a humid region. Well-developed sinkholes that are located at Stop 2 have evidently formed naturally during the past.

STOP 2. Hendricks Lane Sinkholes
Positions of at least four sinkholes can be seen in the field to the south. They can be recognized by stands of large trees. Farmers were not able to work the land at sinkholes and trees were allowed to grow there. A sinkhole in the field to the north was covered during the early 1980's. It will be interesting to see how long it will remain covered and tillable.

Limestones in roadcut
Limestones in roadcut, former railroad overpass at hamlet of High Falls.

Rondout Creek meander on left.

Limestone on right, New Scotland and Kalkberg Formations.

STOP 3. Pompey' s Cave
A suggested explanation of the initiation of this cave and subsurface drainage follows. Kripplebush Creek has cut through a recessional moraine at the hamlet of Kripplebush and its course meanders considerably as it flows southeasterly across the post-glacial lake bottom deposits and empties into the Rondout Creek nearby. The Rondout Creek flows over a shrinking waterfall ~2 miles north at High Falls since the caprock is dipping west. As the waterfall height lowers and as the Rondout Creek above the waterfall continued to erode through the carbonates, the base level of the Kripplebush Creek was lowered and the local water table dropped. Subsequently, the lower reach of the Kripplebush Creek was rejuvenated and has cut into the Rondout carbonates. The water evacuated from the cave beneath the Mg-Carbonate member of the Rondout Formation following the lowering water table, and eventually the surface stream began seeping downward through and, thereby, enlarging joints in the Rondout carbonates. This probably occurred first in joints near the Rondout Creek, then later in joints farther upstream. Now, the stream enters several "swallow holes" upstream and has become an underground stream flowing presumably into the Roundout Creek. Indications are that this process will continue and, in fact, the upstream, meandering portion of the stream seems to be rejuvenated more each year; it is expected that the increased downcutting will result in additional sinks developing in the stream bed as long as the surface water can enter a cave below it.
Note the character of the dry stream bed near the Lucas Turnpike bridge. Joints are apparent, and well-developed mudcracks can be observed. An entrance to the cave is located a few hundred feet "upstream" in the dry stream bed, and a homemade ladder is constructed to assist people who wish to enter the cave. CAUTION: The property owner has not chosen to "post" or restrict valid study of this local phenomenon. If you decide to enter, please realize it is your decision and you have decided to assume any associated risk. Before studying or entering the cave, you may wish to walk upstream farther to see a partial collapse of the stream bed into the cave below, and to observe the stream entrance holes farther upstream. CAUTION: The fields nearby are used for pasture for cattle. Be careful that a bull in not loose nearby or you may need to make a hasty retreat downstream! If you decide to enter the cave, check each ladder rung very carefully to determine if it will hold your weight. Always leave at least one person on the surface to obtain help if the ladder breaks.

STOP 4. Rondout Creek Meander
This vantage point provides an excellent view of the Rondout Creek at a magnificent sweeping mobile meander. During flood stage, the stream severely undercuts its bank and some slumps and subsidence have occurred.

STOP 5. Artesian Spring and Pool
A fence protects an unwary visitor from the artesian spring (locally called a sinkhole) located near the western boundary of the RMC parking lot. This is reported to be the third protective fence placed around this feature, following the enlargement of the pool and loss of the fences. This lot was a sand and gravel quarry that was mined until the operators noted the appearance of groundwater surfacing. After mining ceased, the property was developed in the 1970's as the current operation. Water broke through the sand forming an apparent sinkhole. Evidently, sand is flushed out and onto the land surface with occasional increased water flow, causing a pit to form filled with water. The pool within this pit was plumbed to be about 40 feet deep in the early 1980's. I have observed water, and possibly gas bubbles, ejected one or two feet into the air, with the appearance of "rising" and/or "jumping" fish! The. aquifer feeding this spring is unknown and somewhat of an enigma, since the elevation of discharge is about 30 feet higher than the nearby unnamed stream. The surrounding surface is generally at a lower elevation and increased discharge does not seem to be immediately correlated with rainstorms. No geochemical tests of the water or continuous studies or monitoring of discharge are known. Could this spring be the outflow of a leak in the nearby Rondout Pressure Tunnel section of the New York City Aqueduct? Clearly, additional study is warranted and could prove interesting. In any event, it does indicate that the hydrology of this area is not well-known.

Narrow former underpass of former railroad.
The rocks used in constructing this underpass/railroad bridge foundation were taken from the old Delaware and Hudson Canal works

STOP 6. Rest Plaus Road Proposed Landfill Site
This site was considered as a landfill for the Town of Marbletown in the early 1980's. The landfill would be located within the shielding forest to the northeast with a leachate lagoon located on the southwest. The soils of the land on the western portion of the property would serve as the mine for the daily landfill cover, as well as to provide for some future expansion of the landfill if needed.
Near the southern boundary of the property, a small stand of trees can be seen from the road in the field. Close examination shows that the trees are growing within and around a shallow, filled sinkhole. Blocks of the relatively soluble Becraft Limestone are exposed, and dissolution has occurred between the separated limestone blocks which are at slightly different attitudes. Some surface runoff is passing into this depression. At various depths, Becraft Limestone and other limestones less susceptible to solution and sinkhole development underlie the proposed lagoon and landfill areas, as well as the proposed landfill nine.
Some less obvious solution effects can be observed along joint planes and limestone nodule layers in the Port Ewen mudstones. These appear to occur within 2 m. (~ 6ft.) of the bedrock surface and can be seen after a short walk along the abandoned railroad grade along the east border of the site.
In addition to solution effects calling into question the use of the site as a landfill, there is some evidence that a southeast-northwest thrust in the Port Ewen Formation occurs in the eastern limb of a northeast-trending plunging syncline, projected along the hillside and crossing the abandoned railroad grade. Also, a much smaller, narrower, more tightly folded, northeast-trending and plunging anticline may project into the southern half of the property and may pass through the location of the previously described sinkhole in the Becraft Limestone.
Clearly, additional geology and hydrology investigations are called for before this property should be used as a landfill. The recent search for a town landfill has been abandoned, and there are at present no known plans to determine the suitability of this site.

East overview of Stop 6, former proposed landfill site.

STOP 7. Esopus Creek - "Bathtub"
This area is called locally the Bathtub. Reportedly, sand and gravel mining was conducted here, along the outside of a stream meander. During a flood in the 1960's, the stream cut through the narrow berm separating the quarry from the stream, and the quarry became a portion of the stream. Mining operations have been relocated to several other areas of the Esopus Floodplain; we will visit some of the newer operations.
Environmental problems associated with a breach of quarry operations that could affect the Esopus Creek include the following. (1) The stream slows when entering the wider, deeper area, and exposure to additional light coupled with less shade from protective shoreline trees will warm the waters. The warming waters will be expected to hold less dissolved oxygen and the stream ecology will, thus, change. This renowned fishing stream will probably produce fewer trout in the future. (2) More rapid stream bank erosion may be expected during flood stage causing an increase in stream sediment load. This also is expected to change the stream ecology. (3) Increased erosion here should produce increased stream channel deposition downstream, and more overbank flooding more often. Communities downstream include the hamlet of Hurley, the City of Kingston, the hamlet of Lake Katrine, the Town of Ulster, and the Village of Saugerties; increasing concern is being expressed in local newspapers by citizens and local government officials (Kwiatoski byline, Kingston Daily Freeman, 10/2/87 and 10/5/87). The usual call is for the Army Corps of Engineers to dredge, channelize, or to otherwise provide increased flood control of the middle Esopus Creek.

STOP 8. Town of Marbletown Park, Esopus Creek
A kame can be seen to the south that has been mined since the late 1970's. A kame is valuable for sand and gravel mining, since it is sorted by glacial-fluvial processes and operations can thereby save considerably.
The Esopus Creek enters the valley about one-half mile upstream (west) of this stop and begins a broad meander to flow northeasterly. Mining of sand and gravel deposits was done on the floodplain on the opposite side of the stream, evidently in accordance with (then) existing state and local regulations that required a minimum 10-foot berm to be left untouched. Floods of the late 1970's repeatedly breached the berm; and repeated efforts to reinforce the berm with at first gravels and then a steel wall continually failed. Rapid bank erosion has begun on the south side of the Esopus. In 1977, a row of trees about 20 feet wide existed from the man-made sand beach to the east along the creek. These have been washed away. The channel downstream is evidently filling with gravels, and it appears the stream may be changing its course here because of, or in spite of, the mining disturbance.

On left, is this a meander scar of an earlier Esopus Creek channel?

Is this an oxbow of an early Esopus Creek?
This was a nearly filled pond until the 1980's, when it was dredged to provide a more attractive pond. It is possible that the stone house was constructed alongside a well-flowing stream two or three centuries ago. Several small streams flowing into the valley seem to flow into meander scars of a once larger stream. Of course, they may have constructed these meanders themselves if they previously had a greater discharge. However, several other undoubtedly Esopus Creek oxbows and meander scars are apparent from a study of the Kingston West Quad.

Sand and gravel mining on right side
Operation has been intermittent during the 1980's.

STOP 9. Fording Place on Esopus Creek.
Sand and gravel mining can be studied here. Note that an operation in modern alluvium, ground moraine, and lake deposits must include mechanical separation or grading. This increases mining costs to the operators. Occasional glacially carried boulders and cobbles can be found here, recognized by facets and striae. Note also that the operations of the mine are near the stream and the berm is occasionally breached by floods. When water is low, many local residents ford the stream here with their vehicles. The hamlet of Marbletown is located on the other side.

Fallen rock zone; cliff prone to landslides.
This valley wall was probably cut by the glacier(s), but the cliff base may have also been undercut by an early meandering Esopus Creek.

Landslide prone area.
Rockslides and slumps occur here about every 7 to 15 years, often covering the roadway. The highway department has each time quickly removed the supporting talus at the base of the cliff, probably encouraging additional future landslides. Note the "blocks" of rock (Hamilton Formation, shales and siltstones) that are ready to break loose along joints.

Crossing over a meander scar of early Esopus Creek?
At the end of Evergreen Lane, a broad, open oxbow lake, a meander of an early Esopus Creek can be seen (on private property). This oxbow lake is apparent on the Kingston West Quad.

Lawns on left were damaged in 1987
Lawns of the houses on the left were severely damaged by Esopus Creek floodwaters during the heavy rains of mid-April, 1987. If the rains had occurred with a melting snow, the damage might have been more serious. Large "potholes" or "swirl-holes" over 10 feet in diameter, several feet deep, developed in at least one lawn. The damage has since been repaired by residents.

STOP 10. Oxbow Lake
A large gravel-covered area on the right side of the road provides ample parking space. If you cross the road, use extreme caution since cars are leaving a controlled-access four-lane highway here and are often travelling at a high speed.
Some area residents believe that the stream's channel was changed by man during the construction of this newer section of Route 209, and that the pond along the west side of the highway was where the pre-highway Esopus Creek was flowing. The 1942 Kingston West Quad, however, shows that this existed before the highway was constructed in the early 1960's. It is certain evidence that the Esopus Creek has changed its course in the past, and probably will continue to do so in the future barring complete channelization.
This oxbow is undergoing rapid eutrophication now, since the nearby agricultural fields are heavily fertilized; normal runoff is feeding the vegetation within this oxbow.

STOP 11. Plaza Flood Control Project
Flooding during January thaws and spring melts of 1976-1978 caused citizens, commercial interests, and politicians to request the Army Corps of Engineers to provide flood control. The Corps of Engineers at first suggested that flood control might not be wise since it might cause increased flood problems downstream (north), but a compromise was agreed upon to construct flood control on the Plaza side only. High waters are now not a hazard to the stores, but some people have wondered if flooding of the opposite side might become more common now that nearly all the flood waters must flood onto the opposite side.

Continue driving along the flood control dike.
Note that high flow water can be diverted to a confined wetland to allow some groundwater recharge. Exit the Kingston Plaza and turn right onto Schwenk Drive. Turn right (north) at traffic light onto Washington Avenue.

H: GENERAL STRUCTURE AND ORDOVICIAN STRATIGRAPHY FROM THE
MARLBORO MOUNTAIN OUTLIER TO THE SHAWANGUNK CUESTA, ULSTER COUNTY, NEW YORK
MICHAEL J. KALAKA
1184 Ocean Avenue, Sea Bright, New Jersey, 07760
RUSSELL H. WAINES
College at New Paltz
New Paltz, New York 12561
The Lower Wallkill Valley lies within the western portion of the Appalachian fold belt and is approximately 70 miles (43.5 km) northwest of New York City (fig. 1).
Within the study area the eastern side of the valley is flanked by Ordovician flysch deposits forming the Marlboro Syncline (Waines, 1986). On the western side is the Shawanqunk Mountain escarpment capped by the Upper Silurian Shawanqunk Conglomerate.
The Middle to Late Ordovician Martinsburg Formation forms the bedrock of most of the Lower Wallkill Valley while the bedrock on the eastern side is underlain by Middle to Late Ordovician Quassaic arenites. Most of this is usually blanketed by Wisconsinan till or alluvial deposits derived from the Wallkill River (Connally and Sirkin, 1967).
Because of structural complexities, infrequent fossils, and lack of stratigraphic markers it is difficult to establish close lithologic correlation within the Martinsburg Formation.
Previous attempts to determine and depict the structure and stratigraphy of the area by Holzwasser (1926), Rickard(1973), and Waines et al. (1983) have not been entirely successful. An increase in bedrock exposures as a result of recent road construction together with geologic data acquired from the Delaware West Branch Aqueduct (City of New York Board of Water Supply, 1938, 1939), Catskill Aqueduct (Board of Water Supply, 1905- 1918), and logs from three wild cat wells (Susi, Modena, Minnewaska) have enabled the construction of a composite northeast-southwest structure section (Kalaka, 1985, fig. 23). This section extends from the center of the Marlboro Mountains near Lloyd, New York westward through the Martinsburg Formation in the eastern central, central, and western portions of the valley continuing under the Shawangunk Mountains almost to Wawarsing, New York (figs. 2 and 3).
The section reveals three major structural domains (east to west) : (1) a monoclinal, southeast-dipping domain in which an arenite facies shales to the west and southwest (west limb of the Marlboro Syncline); (2) a complex domain involving mostly shales (central portion of the Wallkill Valley); (3) an open fold domain involving mostly shales (western portion just east of and under the Shawangunk Cuesta) (Kalaka, 1985, fig. 24), (fig. 2).

H: GENERAL STRUCTURE AND ORDOVICIAN STRATIGRAPHY FROM THE
MARLBORO MOUNTAIN OUTLIER TO THE SHAWANGUNK CUESTA, ULSTER COUNTY, NEW YORK

Allochthonous Normanskill on the east side of the Esopus Thrust.
Shale near telephone pole on left side of road is probably allochthonous Normanskill on the east side of the Esopus Thrust.

Crossing buried Esopus Thrust.

STOP 1. Here we are in middle third of Chodikee Formation
Here we are in middle third of Chodikee Formation (Strater, 1983) the uppermost unit of the Quassaic Group. We are located in the east limb of the Marlboro Syncline. The age of these autochthonous strata is Late Ordovician. Beds are vertical to slightly overturned to the west.

Bridge over Black Creek
Bridge over Black Creek fault where east limb of Marlboro Syncline has thrust westward over west limb of syncline.

STOP 2. Here is a more shaley version of the Chodikee Formation.
Fossils include brachiopods and highly deformed cryptolithids. Strata typically dip east.

Arenitic formations are shaling out to the southwest.
We will be moving down section for the next 2.1 miles and the normally arenitic formations in the Quassaic beneath the Chodikee are shaling out to the southwest.

Outcrop of Slabside Formation (?) on right.

Shaupeneak or Rifton Formation in road cut.
This is the last exposure in the east-dipping domain on NY 299.

Entering eastern margin of complex domain.

STOP 3. Here is a typical example of complex domain strata
Here is a typical example of complex domain strata in the road cut on the north side with a good east-west sectional view. The strata are Medial Ordovician Bushkill shales and siltstones.

Bushkill outcrop on left.

STOP 4. Deformed shales and siltstones with east-dipping cleavage.
Here, beneath the poison ivy, are deformed shales and siltstones with east-dipping cleavage. Again, these appear to be Bushkill and the exposure occurs near the center of the complex domain.

Head west across Wallkill River floodplain.
Cross bridge over Wallkill River and head west across Wallkill River floodplain.

View of Shawangunk Cuesta at 12 o'clock.

Roadcuts observed over next 2.6 miles are in the complex domain.

STOP 5. Extensive outcrop occurs at base of hill along river.
Predominantly east-dipping argillites are involved in some folding and faulting. A foundation of an old covered bridge is observable. Here is another aspect of the complex domain. The strata are apparently Bushkill. No fossils have been found.

STOP 6. This is a hiking stop
This is a hiking stop and we have been given special permission by the owner of the mill to walk across the property along the north bank of the Shawangunk Kill. Please stay with your leader and do not wander.

STOP 6b. Concrete dam across the Shawangunk Kill.
The first phase of the hike is about 1100 feet to a concrete dam across the Shawangunk Kill. On the far side of the stream and on the near side, when water is low, one can see an overturned section of east-dipping interlaminated siltstones and argillites which aggregate some 2000 to 2500 stratigraphic feet.
As far as we can tell, there is little faulting other than bedding plane dislocations and the sequence does not appear to belong in the complex domain. The differences between these strata and those at the next stop are noteworthy.
No samples in the dam area, please.

STOP 6c. The top of the argillite and silt sequence.
Proceed upstream from the dam along the berm of an abandoned canal. Watch out for woodchuck holes in the berm. They can be treacherous (the holes - not the woodchucks).
Proceed about 1,000 feet upstream from the dam to a point where a large hill on the north side of the stream closes to the stream. Here are numerous arenite layers in the shales, some up to a foot or so in thickness. These arenites are also overturned, dipping east as can be seen by flow structures on the basal bedding planes. This sequence seems to occur at the top of the argillite and silt sequence. The arenites can be traced southwestward into an ever-thickening arenite-shale sequence which seems to approximate the position of the Ramseyburg member in the Martinsburg Formation much further south. The argillite-silt sequence is most likely upper Bushkill if the foregoing is correct. This sequence in the Shawangunk Kill was first noted by Paul Kopsick (1977).

STOP 7. This extensive road cut is in the Bushkill shale
Walk uphill (west) along one side of highway and return, walking down other side. This extensive road cut is in the Bushkill shale and strata generally are right side up and dip east, but faulting and some drag folding suggest imbricate thrusting. This exposure is thought to represent a portion of the upper plate thrust over the lower plate exposed at STOP 6. A chance rockfall in this cut yielded an extensive fauna including bivalvia, articulate and inarticulate brachiopods, cryptolithid trilobites, graptolites, gastropods and burrows. Weathering rapidly reduces the shale to fine rubble.

STOP 8. Martinsburg strata may be Pen Argyl Equivalent
STOP 8. Here Martinsburg strata, which appear to be Bushkill, may actually be Pen Argyl Equivalent though they do not resemble the latter. Here and at STOP 9, a short distance away, the strata occur in the open fold domain and in the immediate vicinity the overlying Shawangunk conglomerate may reflect Acadian or later deformation which was superposed on a predominantly Taconian structure.

STOP 9. Scenic Overview and Field Trip Conclusions
Facing northwest we see the relative attitudes of the underlying Martinsburg (Pen Argyl Equivalent?) and the overlying Shawungunk conglomerate. Although the angular unconformity between the two can be projected, the actual contact can be seen just south of Rt. 44-55 at the base of the Shawungunk (Waines and Sanders, 1968). The study of the relative structure of the Shawangunk and Martinsburg in this immediate vicinity was conducted by Persico (1984). He concluded that same Taconic structures were further deformed at a later time.
Next, a view to the southeast and east stretches beyond the immediate Wallkill Valley to the Hudson Highlands and the Hudson River Gap (southeast) and the Housatonic Ridge along the Connecticut border to the east. Closer at hand, to the east, we can retrace our general progress of the day from the irregular ridge of the Marlboro Mountains (overturned east limb of the Marlboro Syncline). Slightly closer we drop in elevation across the east dipping monoclinal domain which cannot be recognized from this viewpoint. We know that the complex domain centers an the lower elevations of the Wallkill Valley, but again the domain cannot be recognized from here. Similarly, the open fold domain and its eastern boundary fault give no indication of their presence. It must be concluded that only extensive exposure data (borings, tunnels) are necessary to augment meager or fortuitous exposures as in Stops 6 and 7.

I: BLOCKSTREAMS AT MILLBROOK MOUNTAIN, TOWN OF GARDINER, ULSTER COUNTY, NEW YORK
ROBERT W. CUNNINGHAM
College at New Paltz
New Paltz, New York, 12561
Peter A. Robson
MITRE Corporation
San Antonio, Texas, 78284
To raise questions concerning the origin of the features found in the scree below Millbrook Mountain.
INTRODUCTION AND DESCRIPTION
Millbrook Mountain is a three quarter mile long anticlinal structure forming a topographic high (elevation 1620 feet, 495 m.). It is located about one mile south-southeast of Lake Minnewaska in the Shawangunk Mountains. This anticline is truncated on the east side by a 350 foot (107 m.) cliff and is composed entirely of Shawangunk conglomerate dipping up to 55 degrees to the northwest. While the vista from the top offers a commanding view of the Wallkill valley and Shawangunk Mountains, the most unusual and engrossing geomorphic features lie 500 feet below in the talus at the foot of the cliff forming Millbrook Mountains' south-east face. Instead of forming the 25 to 35 degree straight talus common to the Shawangunks, this scree displays a varied mixture of steep slopes, block streams, ramps sub-parallel to the cliff face, rampart-like ridges, valleys and closed depressions (figure 2).
These features are composed of blocks of Shawangunk conglomerate averaging five to ten feet cubed 1.5 to 3 m3, with some blocks forty feet (12m.) in length (Robson, 1972). These blocks are significantly larger than those in the scree presently being deposited at the base of Millbrook Mountain. Block streams are largely lacking vegetative cover, exposing the bright, white surfaces of conglomerate to view; this is what initially aroused the curiosity of Dr. Russell Waines who encouraged the initial studies of these talus features by Robson and Cunningham in 1972.
The block streams generally slope from one to ten degrees along their long axes, while the adjacent rampart-ridges slope at greater than thirty degrees. The steepest slopes are on the main rampart (figure 2) and attain a maximum angle of repose of 41 degrees (Cunningham and Robson,1973). Mature hemlocks up to three feet 1 m.) in diameter growing in several feet of humus cover the slopes and tops of the ramparts indicating a long period of stability. The block stream ramps, valleys, and depressions are barren rock with occasional small shrubs and sparse pines of small diameter. The newer talus forming at the foot of the cliff, and spreading onto the larger blocks supports mixed deciduous and coniferous trees of moderate size.
The steep, vegetated slopes, topped by the rampart-like ridges sit east of relatively unvegetated high valleys (figure 2). Block streams A and B descend up to 0.5 miles (0.8 km) north and south from valleys 2 and 3 respectively. Block stream C descends from valley 4 extending to the south then to the southeast. These contrasting surface features offer good evidence that this block scree has been redistributed about the base of Millbrook Mountain.
In the northern part of the area the heavily vegetated slopes have apparently remained stable, while the scree behind the main rampart has presumably migrated to the north and south leaving shallow valleys (2, 3) separated by a saddle.
Another feature occurs south of block stream C where a mass of scree, set out from the cliff face occurs as a domal structure (figure 2) with blocks dipping outward in all directions. A small vegetated area separates this structure from the unvegetated block stream to the north.
On the steep eastern face of block stream B, is an alignment of several thin, unvegetated crescents of scree trending horizontally and surrounded by vegetated slopes (figure 2).
When hiking on the talus below Millbrook Mountain good shoes are required! Good physical conditioning and agility are important. Permission of the owner is necessary! He lives just north of the target area up long driveway on the west side of the road.
Approach scree from below (east).

I: BLOCKSTREAMS AT MILLBROOK MOUNTAIN, TOWN OF GARDINER, ULSTER COUNTY, NEW YORK

STOP 1. Millbrook Mountain Scree Slope
Millbrook Mountain is a three quarter mile long anticlinal structure forming a topographic high (elevation 1620 feet, 495 m.). It is located about one mile south-southeast of Lake Minnewaska in the Shawangunk Mountains. This anticline is truncated on the east side by a 350 foot (107 m.) cliff and is composed entirely of Shawangunk conglomerate dipping up to 55 degrees to the northwest. While the vista from the top offers a commanding view of the Wallkill valley and Shawangunk Mountains, the most unusual and engrossing geomorphic features lie 500 feet below in the talus at the foot of the cliff forming Millbrook Mountains' south-east face. Instead of forming the 25 to 35 degree straight talus common to the Shawangunks, this scree displays a varied mixture of steep slopes, block streams, ramps sub-parallel to the cliff face, rampart-like ridges, valleys and closed depressions (figure 2).
These features are composed of blocks of Shawangunk conglomerate averaging five to ten feet cubed 1.5 to 3 m3, with some blocks forty feet (12m.) in length (Robson, 1972). These blocks are significantly larger than those in the scree presently being deposited at the base of Millbrook Mountain. Block streams are largely lacking vegetative cover, exposing the bright, white surfaces of conglomerate to view; this is what initially aroused the curiosity of Dr. Russell Waines who encouraged the initial studies of these talus features by Robson and Cunningham in 1972.
The block streams generally slope from one to ten degrees along their long axes, while the adjacent rampart-ridges slope at greater than thirty degrees. The steepest slopes are on the main rampart (figure 2) and attain a maximum angle of repose of 41 degrees (Cunningham and Robson,1973). Mature hemlocks up to three feet 1 m.) in diameter growing in several feet of humus cover the slopes and tops of the ramparts indicating a long period of stability. The block stream ramps, valleys, and depressions are barren rock with occasional small shrubs and sparse pines of small diameter. The newer talus forming at the foot of the cliff, and spreading onto the larger blocks supports mixed deciduous and coniferous trees of moderate size.
The steep, vegetated slopes, topped by the rampart-like ridges sit east of relatively unvegetated high valleys (figure 2). Block streams A and B descend up to 0.5 miles (0.8 km) north and south from valleys 2 and 3 respectively. Block stream C descends from valley 4 extending to the south then to the southeast. These contrasting surface features offer good evidence that this block scree has been redistributed about the base of Millbrook Mountain.

J: THE WHITEPORT DOLOSTONE OF THE LATE SILURIAN RONDOUT GROUP, VICINITY OF KINGSTON, ULSTER COUNTY, NEW YORK
Brian V. Fetterhoff
New Paltz, New York 12561
The term Whiteport was proposed by Rickard (1962) for a dolostone referred to by Hartnagel (1903) as the 'Rondout' in a rather restricted sense. Rickard suggested "that the name Rondout be applied to the dolomite strata subjacent to the Manlius everywhere in New York" (p. 3O). Thus, according to Rickard, in the Rondout Formation the Whiteport is the uppermost of three members (Whiteport, Glasco, Rosendale), with a type section near Whiteport, New York.
Harper (1969) described the Whiteport as a "buff-weathering, light-gray to blue-gray on fresh, argillaceous silty dololutite. It is mudcracked, finely laminated, commonly burrowed, and very rarely fossiliferous" (p. 14). Harper's environmental interpretation is that of a mudflat facies. Harper acknowledged that lime interbeds do exist within the Whiteport in the vicinity of Kingston:
"One prominent interbed has been termed the "Twalfskill Bed" (Wanless, 1921; Van Ingen, local unpublished field term). Its thickness averages about one foot, and it is found to occur in the majority of sections in the Rosendale quadrangle... In this blue weathering, dolomitic limestone the fossils are commonly algal-coated, a fact which prompted Wanless to describe it as the "Algal Reef Limestone" (p. 14-15).
An additional limestone was recognized by Harper in the base of the Whiteport; a "two-foot interval of interbedded ostracod-rich calcarenites, calcilutites and calcareous silty dolomites" (p. 119).
Waines and Gomez (1977) divided the Whiteport (from Accord to Kingston) into five recognizable units (from top to bottom): Unit one, an argillaceous shaly dolostone (found south of Kingston), unit two, a massive weathering dolostone (unit one of this paper), unit three which can be subdivided into an upper, laminated portion and a lower, organic "reef" (unit two here), unit four, a massive dolostone (unit three here), and unit five, a somewhat fossiliferous lime unit (unit four here). This unit, which was often placed in the top of the Glasco, is actually a separate unit in the base of the Whiteport.
It is the presence of these limestone units which appear in the vicinity of Kingston that allows additional interpretations of environments and, due to their fossiliferous nature, a determination of age.

J: THE WHITEPORT DOLOSTONE OF THE LATE SILURIAN RONDOUT GROUP, VICINITY OF KINGSTON, ULSTER COUNTY, NEW YORK

Mt. Marion Formation (Middle Devonian)
For the next 2.1 miles are extensive roadcuts in gently dipping siltstones and shales of Mt. Marion Formation (Middle Devonian).

Roadcut shows Lower Devonian strata.

STOP 1A: Wygant North. Roadcut Exposing Thacher, Whiteport, Glasco, And Rosendale.
(PLEASE DO NOT CROSS HIGHWAY. BEWARE OF FALLING ROCK - WEAR HARD HATS.)
Whiteport
Thickness of Whiteport is five feet. Unit two is not present in this section, and unit one rests disconformably upon unit three.
Glasco
Note lower disconformable contact with massive dolomitic mudstones of the Rosendale. Coverstone lithology of unit A (subunit 2) characterized by laminar stromatoporoids; chiefly Stromatopora clarkei, intercalated with stick-like tabulates and/or bryozoa, and chert. Take note of the position of this unit in the stratigraphic sequence.
Distinct color change between unit B and C (dark blue vs. light grey). Bedding plane parting marks upper contact of unit C with overlying basal ostracod floatstones of the Whiteport. This unit in the lower Whiteport occurs in virtually all localities studied and serves as an excellent marker bed.

STOP 1B: Wygant South.
Please Do Not Cross Highway.
Whiteport
Unit four is well exposed at this stop. Note abundance of ostracods, and fragments of limestone (intraformational conglomerate) within this unit. Gradational contact with unit three. Unit one and two are not exposed at this stop.
Glasco
Hemispherical stromatoporoids and halysitids found in the basal hemstones are typical of the northern domain. Compare intact halysitid coralla with fragmented types in chainstone. Note laminar stromatoporoids in coverstone and chainstone lithologies of unit A. Pay particular attention to stromatoporoid/halysitid association in low matrix chainstone.
Dominant macro-invertebrates in unit B are solitary rugosa, cladoporid-like tabulates, and stick-like tabulates and/or bryozoa (especially in subunit 2). Unit C is characterized by fossil fragments. Note irregular disconformable upper contact and associated rip-up clasts.
Rosendale
At this location unit one is missing, probably due to erosion. Unit two is massive dolostone. Unit two subunit is a massive dolostone with discontinuous to continuous limestone stringers. Unit three, Wilbur is mottled and contains a fossil marker bed. The bottom portion of this unit is a sandy limestone which rests on Ordovician sediments with angular unconformity. Most likely, unit four was never deposited.

STOP 2: Vlightberg Hill. (Follow Fieldtrip Leaders Up Hill).
Please Follow Pink Ribbon Trail And Do Not Wander - Especially Dangerous Cliffs.
2A: Van Ingen's Wilbur
Rosendale
Unit three, Wilbur is massive but still has that mottled look. Here the limestone is in angular unconformity with underlying Middle Ordovician Normanskill (Austen Glen aspect) graywackes.
2B: South End Of The Vlightberg
Whiteport
Unit four is not present at this stop. Unit two is dolomitized, and the subunits are barely distinguishable.
Glasco
The Glasco is represented by unit C (subunit 2) which consists of dolomitic mudstones, indistinctly laminated dolomitic mudstone, end stringers of fossil hash with quartz grains. Similar horizons occur at stops 3, 5A and 5B.
A small mottled portion of unit one is present.

STOP 3: Sweeney's Stoneyard. (Follow Field Trip Leaders)
No Sampling At This Outcrop - When We Cross The Road Stay On Sidewalk. Do Not Walk On The Flower Garden.) Outcrop Descriptions Will Be Presented By Fieldtrip Leaders On Opposite Side Of Outcrop.
Best exposure for the Whiteport Dolostone in the Kingston area. Unit four is dolomitized at this stop. Unit two can be seen in its two subdivisions, the upper laminated subunit and lover 'reef* subunit. The three subzones within the lower subunit are best exposed here. Note disconformity at the base of units four, two, and at the top of unit two. At the top of of unit one, mudcracks mark the contact with the Thacher limestone.
Cherty boundstone is found near the base of unit A (very thin subunit 1). Unit B contains a lower dolomitic floatstone/lamstone (subunit 1). The upper dolomitic mudstone may be indicative of quiet water in the back reef environment. Note the highs and lows within the stromatoporoid knobs along with laminar and hemispherical stromatoporoids located at similar horizons. Take a close look at the overlying subunit 2.
Rosendale
At this stop all four units in the four-fold proposal are present. The upper limestone of unit one can be seen with its mottled look and a minor parting at the base. Unit two is massive dolostone which has several partings present. Unit three and unit four are present but are hidden behind the fence. Once again do not step on the garden and no samples please.

STOP 4: City Of Kingston Gravel Pit (Follow Fieldtrip Leaders).
The Cliff To The Northwest Is Formed Of An Extensive Sequence Of Upper Silurian And Lower Devonian Strata (Mostly Carbonates) Partly Repeated By Faulting.
Unit four is dolomitized at this outcrop. Fossiliferous horizons can be noted, with concave-down ostracod valves, brachiopods, and solitary rugose corals. Hemispherical stromatoporoids also present. Unit three is covered by talus; unit two can be seen in both subunits. Contact between unit one and overlying Thacher limestone is last mudcrack in unit one.
The cherty coverstone marker bed essentially sits at the base of unit A. The chainstone lithology has thinned relative to the north, contains more matrix and few, if any, laminar stromatoporoids. The cyclic nature of floatstone and lamstone within unit B is best demonstrated at this locality. The base of unit C shows an unusual stromatoporoid growth form. A vertical channel wall and subsequent infillings are encrusted by stromatoporoid coenostea (Parallelostroma constellatum). Once again take note of of the laminar and hemispherical stromatoporoids that seem to co-exist at similar horizons.
This stop represents the standard reference for the Rondout Formation and the type section of the Wilbur member. Here all four units of the Rosendale dolostone can be seen. The cliff to the northeast shows an extensive sequence of all four units. Unit one can clearly be identified below the base of the Glasco. The massive limestone is mottled and the upper portion is darker than the bottom. The Wilbur, unit three, is sandwiched between the dolostone of unit two and unit four. Unit four lies with disconformity on the underlying Binnewater Sandstone.

STOP 5: Callanan's Quarry.
Waiver forms must be signed releasing quarry and its employees of any liability, before entering premises. It is mandatory that hard hats and field boots be worn - no one admitted without such safety equipment. Follow fieldtrip leaders to designated localities. Do not wander - Extremely dangerous overhangs and cliffs.
5A: CALLANAN'S WEST: Field assistants will be on hand to assist (especially keeping fieldtrip participants aware of dangerous cliffs and overhangs). No climbing of any sort.
'Reef' subunit of unit two is present in this section. Undeformed halysitid coral found at this location. Unit four is almost completely dolomitized.
Cherty boundstone marker bed is once again located near the base of unit A. Take a close look at the burrowed horizon and high matrix chainstone (rare entire halysitid corals). Unit B is rather thick at this locality. Take some time to examine the stromatoporoid knobs and the overlying dolomitic mudstone and floatstone with occasional laminates, fissile debris and scattered hemispherical stromatoporoids. The latter was interpreted as a low subtidal to intertidal (?) flat environment.
At this outcrop all four units are present but due to faulting the beds are repeated several times. Unit one can be found sitting under the shale parting at the base of the Glasco. This mottled limestone has a parting at its base. Unit two massive dolostone has several partings. Unit three, Wilbur is mottled and also has several partings. The lower dolostone of unit four is massive with areas that are more calcareous. This dolostone lies disconformably on the underlying Binnewater Sandstone.
5B: CALLANAN'S EAST: Once again follow fieldtrip leaders. Stay away from edge of bench. Do not wander or climb!! Field assistants are instructed to keep field trip participants away from cliff. Stay away from roped off area.
Unit four is no longer present; unit three is over seven feet in thickness. Unit two is much thinner in than the western side of the quarry, and, due to the less abundant fossils within the lower subunit, is now 'off-reef'.
This locality has been the most problematic to decipher due to its seemingly "unusual" character. With the help of marker beds in the Whiteport and Rosendale the intricate nature of this exposure appears to have been clarified. Unit A as usual contains a lower coverstone/boundstone but only fragments of the chainstone remain. Unit B does not contain subunit 1 but is represented by a thick subunit 2 (5.4 feet) consisting chiefly of dolomitic mudstones with fewer floatstones (somewhat cyclic). Some beds are laminated and burrowed. The base of the unit contains wide, deep, vertical burrows that appear related to a horizon on the west side. Unit C is represented by subunit 2 and its associated mixture of dolomitic mudstones and floatstones, rudstones, and black shale at the top. These lithologies contain more fossil debris and quartz grains. Only unit C, at other localities demonstrates these associations.
Unit one, the mottled limestone, is represented in the the cliffs (very dangerous do not climb up talus). Unit two and its subunit along with the Wilbur can be seen on several boulders lying near by. Unit two is massive dolostone which is somewhat calcareous. Again unit two subunit is present, a dolostone with continuous to discontinuous limestone stringers. Unit three, the Wilbur, is mottled, and fossiliferous along with clasts of sandstone present near the base. The Wilbur sits on top of Ordovician sediments at an angular unconformity. Most likely unit four was never deposited here.

K: TIDAL CURRENTS, BIOGENIC ACTIVITY AND PYCNOCLINAL FLUCTUATION ON A LOWER DEVONIAN RAMP: BECRAFT, ALSEN, AND PORT EWEN FORMATIONS, CENTRAL HUDSON VALLEY
JAMES R. EBERT
Department of Earth Sciences
Oneonta, New York 13820-1380
The Helderberg Group (Lower Devonian) of New York State includes eight thin, but extensive formations that comprise two transgressive cycles separated by a minor regression (Rickard, 1962; Head, 1969; Laporte, 1969; Ebert, 1982, 1983). The lower cycle exhibits the classic deepening upward sequence of formations: Rondout, Manlius, Coeymans, Kalkberg, New Scotland (Table 1; Rickard, 1962; Laporte, 1967, 1969) that has been widely cited as an example of epeiric sea (ramp) sedimentation. The regression is recorded by an upper tongue of the Kalkberg Formation and the lower portion of the Becraft Formation (Head, 1969; Arif, 1973; Ebert, 1982, 1983). The upper transgressive cycle is comprised of the Becraft, Alsen and Port Ewen formations and has been assumed to represent a repetition of Coeymans, Kalkberg and New Scotland lithologies and environments (Rickard, 1962; Laporte, 1967). Gross similarity in outcrop appearance had been the only basis for this assumption. Recent descriptions of the upper cycle (Ebert, 1982, 1983, 1985, 1986; Mazzo, 1981, Mazzo and LaFleur, 1984) have indicated significant departures from the characteristics of the lower formations. Comparison of upper and lower cycles (Ebert, 1982, 1983, 1985) has resulted in improved understanding of the processes that operated on the Helderberg ramp.
Tidal sand waves are recognized in the Becraft Formation. This formation and other skeletal grainstone units have previously been interpreted as shoal deposits that accumulated above wave base. The predominance of wave action has always been assumed in these interpretations; however, analysis of sedimentary structures clearly indicates the dominance of tidal currents.
Tidal sand waves occur in a variety of modern environments, from estuarine channels to the open shelf. The simplistic, and possibly erroneous, interpretation of wave dominance in many coarse carbonates probably has led to inaccurate reconstructions of environments and paleogeography, especially when adjacent facies are poorly exposed.
The occurrence of tidal sand waves in a sequence that has been interpreted as representing sedimentation in an epeiric sea (Laporte, 1969) raises important questions about the processes that operate in such seas. Traditional epeiric sea models (Shaw, 1964; Irwin, 1965; Ahr, 1973) have treated these seas as being tideless (Hallam, 1981). These models regard the position of wave base as the primary factor governing the distribution of facies. Tides are considered to be absent or of negligible effect.
Significant tidal exchange in epeiric seas has been disregarded because of the supposed frictional difficulty of moving the tidal prism across such wide, shallow shelves (Shaw, 1964; Irwin, 1965; Mazzullo and Friedman, 1975; Hallam, 1981). Despite this bias, a tidal origin has been demonstrated for many quartz arenites from epeiric sea settings (e.g. Klein, 1970, 1971, 1975, 1977; Thompson, 1975; Johnson, 1975; Swett, Klein and Smit, 1971; Chafetz, 1977; Barwis and Makurath, 1978; Recently, Slingerland (1986) has developed a numerical model that supports the hypothesis (Klein, 1977; Klein and Ryer, 1978) that some epeiric seas could have been tide-dominated. This model for the Upper Devonian Catskill epeiric sea includes the geographic area of the present study. Tidal sand waves of the Becraft Formation and the model of Slingerland suggest that, at least, the shallow portions of the northern Appalachian Basin may have been tidally dominated throughout the Devonian. It should be pointed out, however, that deeper portions of the basin, especially during the Middle Devonian, were storm dominated (for examples, see Brett, 1986).
Biogenic processes played an important role in the Helderberg sea, as well. The Alsen Formation displays a predominance of biogenically-disrupted fabrics, although remnants of physical structures are also preserved. The overlying Port Ewen Formation also shows evidence of the importance of biogenic activity. A variety of ichnofossils are present in this unit. These traces provide a detailed record of subtle changes in water oxygenation on the deeper portions of the Helderberg ramp. Of particular interest are the cyclic variations in the distribution of Zoophycos, Chondrites and Helminthoida and associated lithologies. These cycles record fluctuations in the position of the pycnocline and its intersection with the sediment-water interface. These fluctuations occurred in response to regional transgression and record the shoreward shift in the location of the pycnoclinal intersection. Both symmetric and asymmetric cycles are recorded. Although PAC-like in scale, these cycles do not seem to fit the PAC motif of shallowing upward. Deepening upward and shallowing followed by deepening seem to be the more typical pattern for these cycles.

K: TIDAL CURRENTS, BIOGENIC ACTIVITY AND PYCNOCLINAL FLUCTUATION ON A LOWER DEVONIAN RAMP: BECRAFT, ALSEN, AND PORT EWEN FORMATIONS, CENTRAL HUDSON VALLEY

Outcrop on left displays Taconic unconformity

Rip Van Winkle Bridge toll plaza
Outcrops on both sides of road show chevron folds in the Austin Glen Formation, cross Hudson River $0.50 toll for passenger vehicles

Outcrop on corner is in Manlius Formation

Small outcrop of Normanskill Formation.
The hill to the right of the road is Becraft Mountain, an outlier of the Helderberg Group

STOP 1. Becraft Mountain
Inactive quarry of the Independent Cement Corporation on Becraft Mountain outlier ("Becraft Hills"), located in northeast quarter of the Hudson South, New York 7.5 minute quadrangle, just east of Rt. 9, approximately 1 mile south of Hudson.
References: Grabau, 1903; Rickard, 1962
Description: A small pit in the Manlius and Coeymans formations can be seen to the left of the access road to the main quarry. Before entering the main quarry, exposures in the New Scotland Formation are visible along the access road. The main quarry is quite extensive; however, we will concentrate on the northern end. The lower Helderberg formations are largely submerged, but excellent exposures of the upper formations may be studied throughout the quarry.
The upper contact of the New Scotland Formation is clearly exposed in the northern wall of the quarry. Above the New Scotland is a thin (1.8 m) unit that I interpret as the easternmost extension of Rickard's (1962) upper tongue of the Kalkberg Formation. Slightly less than four meters of Becraft subfacies 1 overlie this unit. Subfacies 2 (8.5 m) and subfacies 3 (1.8 m) occur above subfacies 1. The Alsen Formation (2.5 m) is the highest unit present in the quarry.
The eastern position of the Becraft Mountain outlier places this exposure in a more shoreward position relative to localities in the main outcrop belt of the Helderberg Group. This is clearly reflected in the character of the upper formations. Subfacies 1 for example, exhibits fewer and thinner silty interbeds and drapes than at other localities in the central Hudson Valley, an indication of stronger current action in shallower water. Holdfasts of Aspidocrinus scutelliformis are usually sparse in this unit. Elsewhere, this holdfast is abundant in subfacies 1. These two factors combine to give subfacies 1 an overall appearance that is similar to that of subfacies 2 at other locations west of the Hudson. Erosional surfaces and silt drapes within sets of cross stratification are the major features to be observed in subfacies 1 at this stop.
Subfacies 2 is clearly exposed in the quarry, but access for large groups is difficult and potentially dangerous. For this reason, this unit will not be observed here. The general character of subfacies 2 can be seen from a distance, however. Thicker bedding, coarser textures and an abundance of A. scutelliformis and Gypidula pseudogaleata differentiate this unit from subfacies 1. The relative freshness of the exposure and the coarseness of subfacies 2 make observation of sedimentary structures difficult. Interbedding of rudstone and grainstone is the dominant structure. This interbedding is interpreted as vertically accreted tidal bundles. Unimodal cross stratification is common in the center of the unit, but may also be present elsewhere.
Subfacies 3 occurs just below the Alsen Formation. This unit is superficially similar to subfacies 2, but may be differentiated by the presence of bioturbate fabrics and the rootlike holdfast Clonocrinus(?). This unit is readily observable in the quarry, but is better studied at STOP 2, owing to the weathered character of that exposure.
By virtue of its position near the pre-quarry ground surface, the Alsen Formation is better weathered than other units in the quarry. Sedimentary structures and textures are highlighted by this weathering. Nodular chert also helps to differentiate this formation. Herringbone cross stratification, argillaceous interbeds, vague grading and bioturbate fabrics are the important features to note. Faunal differences from the underlying Becraft are evident in the decrease in crinoidal debris and brachiopods and the obvious increase in abundance and diversity of bryozoans. The Alsen Formation at this stop displays significantly more physical sedimentary structures than at other exposures. This is further evidence of a shallower position on the ramp for this location.

View of Catskill Front across the Hudson

Excellent exposure of the Taconic unconformity on offramp.

Large outcrop in Helderberg Group
These exposures continue for next half mile, units show complex deformation (see Marshak, 1986).

STOP 2. Catskill Creek In Austin Glen.
CAUTION: TRAFFIC IS OFTEN HEAVY AND FAST-MOVING. CROSS TO SOUTH SIDE WITH EXTREME CARE.
Location: Waterfall and rapids on Catskill Creek, below and just south of the Rt. 23 bridge over the creek, approximately 0.35 miles northwest of the Rt. 23 bridge over I-87. The deep, narrow valley of Catskill Creek is known as Austin Glen or Leeds Gorge in this area.
References: Section 44 of Rickard (1962), Structural geology is described by Marshak (1986), STOP 2B, see also STOPS l and 2.
Description: The near vertical bedding at this location has created a natural dam across Catskill Creek. Resistant beds of the Glenerie Formation and the Upper Helderberg Becraft, Alsen and Port Ewen Formations form the dam and subsequent waterfall. Upstream from this dam, the creek has scoured out the less resistant Esopus Formation as it flows parallel to strike. In addition to these units, the top of the New Scotland Formation and the upper tongue of the Kalkberg Formation are also exposed just below the falls on the east bank of the creek.
The upper tongue of the Kalkberg Formation (4 m) and Becraft subfacies 1 (4.9 m) are strikingly similar at this location. The two are differentiated by the abundance of Aspidocrinus holdfasts in subfacies l. This designation follows Rickard (1962). Dune forms, silty and peloidal interbeds and drapes are the essential features to note in this part of the section. Herringbone and unidirectional cross stratification are common, with end-on views of troughs less common. Ripples and cross lamination occur in some of the finer interbeds. The increased abundance and thickness of finer lithologies, relative to STOP 1 suggest that this location occupied a slightly more offshore or down ramp position.
Becraft subfacies 2 (approx. 9.5 m) is exposed in the falls and on the west bank of the creek. Thick to massive-appearing bedding and a nearly white weathered color set this unit apart from underlying and overlying units. As at STOP 1 the coarse texture of this unit makes observation of sedimentary structures difficult. Crude bedding is apparent in some crinoidal, Gypidula - Concinnispirifer rudstones. Planar stratification, grainstone - rudstone interbedding, normal and inverse grading are present. These features are interpreted as upper stage plane bedding and vertically accreted tidal bundles. Cross stratification is present, but is difficult to observe.
Subfacies 3 (1.6 m) is only subtly different from subfacies 2 in overall appearance. This unit is recognized by the abundance of Gypidula and Concinnispirifer and by the pink, root-like holdfasts of Clonocrinus(?). Finer textures and in situ holdfasts indicate reduced turbulence and increased stability of substrate relative to the underlying subfacies.
The Alsen Formation (approx. 11 m) is noticeably darker, finer-grained and chertier than the underlying Becraft Formation. The fauna is enriched in bryozoans relative to subfacies of the Becraft Formation. Crinoidal constituents are less abundant and finer and brachiopods tend to be thinner shelled than in the Becraft.
Sedimentary structures have been largely destroyed by bioturbation. The increase in biogenically-disrupted fabrics and the paucity of physical structures, as compared to the Becraft Mountain exposure, also suggest a slightly more down ramp position for this exposure.
Approximately two meters of the Port Ewen Formation are exposed near the top of the section, just below the Glenerie Formation. The Port Ewen is a moderately fossiliferous, bioturbate wackestone to packstone at this section. Bryozoans dominate the fauna. Trilobites and ostracodes are also common. The Port Ewen is greatly thinned here by pre-Glenerie erosion. Large phosphatic and/or slightly pyritic cobbles in the base of the sandy Glenerie mark this disconformity. These features may be observed in the beds that make up the upstream portion of the "dam".

Note Helderberg outcrops on ramp.

Helderberg, Tristates, Onondaga Limestone and Hamilton Group
Outcrops of the Helderberg Group, Tristates Group, Onondaga Limestone and Hamilton Group may be seen along I-87 over the next 21.4 miles.

Bridge over Esopus Creek

Outcrop in Tristates Group and Onondaga Limestone.

Outcrops in lower Helderberg Group

Outcrops of Austin Glen Formation on ramp

STOP 3. Roadcut on Route 199.
Location: Roadcut through anticline in the upper Helderberg Group on Rt. 199, the approach to the Kingston-Rhinecliff Bridge over the Hudson River. Exposure is 0.7 miles east of the junction of 199 with Rt. 9W and 0.35 miles west of the Rt. 32 overpass.
References: STOP lb of Waines and Hoar (1967); STOP 3 of Heyl and Salkind (1967); STOP 3 of Toots (1976); STOP 9b of Pederson, Sichko and Wolff (1976); STOP 7 of Marshak (1986).
Description: This exposure has been visited on several previous NYSGA field trips for the purposes of illustrating structural features or stratigraphic succession. This trip will examine the sedimentology of the Upper Helderberg Formations exposed in this popular roadcut.
The Becraft Formation (9.5 m) occupies the core of this anticlinal exposure. Slightly less than two meters of subfacies 1 are exposed at the base of the section. Subfacies 2 comprises the remaining 7.6 meters of the formation. Subfacies 3 is absent, although the uppermost parts of subfacies 2 are somewhat similar to subfacies 3. Minor silty interbeds may be found in places in the lower parts of subfacies 2. These interbeds are commonly cross laminated and some show paleocurrent reversals relative to adjacent cross-bedded grainstones. Structures in the grainstones are difficult to observe on this relatively fresh face.
The Alsen Formation (6.3 m) sharply overlies subfacies 2 of the Becraft Formation, although several beds of Becraft-like grainstones are interbedded throughout the lower few meters of the Alsen. Bioturbate fabrics predominate in the grainstones and packstones of this unit. The contact with the overlying Port Ewen Formation is readily recognized, but appears to be gradational.
All five lithologies that make up the Port Ewen Formation (24 m) are present in this exposure. Cyclicity is most noticeable in the distribution of the nodules and beds of peloidal grainstone. Asymmetrical and symmetrical cycles are present.
Nodules are thoroughly burrow-mottled, except where recognizable ichnogenera are present, typically Chondrites and Zoophycos. Bioturbation is more intense within nodules than in the surrounding lithologies. Most nodules have sharp boundaries. However, some nodules exhibit a gradual decrease in the degree of bioturbation into the surrounding lithologies. Differential compaction between nodular and non-nodular lithologies is readily apparent. Note the absence of evidence for soft-sediment deformation which Mazzo (1981) and Mazzo and LaFleur (1984) suggest should be ubiquitous.
The distribution of ichnofauna within cycles is such that Zoophycos and Chondrites are most abundant in the centers of symmetrical cycles. Deeper water forms are present in the upper and lower portions of these cycles. Several nodular beds exhibit pyrite impregnation of the upper surfaces. Borings (?) are associated with these surfaces, as are pebbly, phosphatic and/or pyritic clasts that contain similar biogenic structures. Periodic exhumation of some nodular horizons and the development of patchy hardgrounds are suggested by these features. Additional evidence for early cementation is provided by synsedimentary fractures in some nodules that are partially cement-filled, with sediment overlying cement.
Chert is present as rinds that centripetally replace nodules of peloidal grainstone and as continuous beds that were originally peloidal. These features tend to be more common within five to eight meters of the contact with the Glenerie Formation.
Sandy, brachiopod-rich beds of the Glenerie Formation are present on the west limb of the fold. A covered interval of approximately 5 meters separates this formation from the Port Ewen below.

L: THE CATSKILLS REVISITED
Constantine Manos and Russell H. Waines
State University of New York, College at New Paltz
On this trip we hope to present an overview of sediments that accumulated to form the Catskill Clastic Wedge. Rather than develop a paper and field trip guide that deal entirely with new research, we plan to visit some outcrop locations that have already been reported in the literature, add one or two new locations, including a fossil collecting stop in the Mt. Marion formation, and travel to the Blenheim-Gilboa Hydroelectric Power Station north of Grand Gorge.
The study first begins in the post-Onondaga Bakoven shales at an outcrop in the Kingston area. These dark shales, deposited in a deep, euxinic marine environment, are successively overlain at other locations by mudstones, shales, and sandstones that comprise the first gray, and then red beds to be seen as we travel stratigraphically higher into the Catskill Front. The Stony Hollow formation, which we may see en route, was deposited on a distal prodelta slope. The first four stops are clustered a few miles within the trip's point of origin at locations where the Bakoven, then Mt. Marion mudstones, fossiliferous Mt. Marion iron-stained mudstones exposed in a somewhat remote quarry, and the Plattekill sandstones are exposed. The Ashokan formation, which underlies the Plattekill, was deposited on an intertidal shelf, while the Plattekill best represents a piedmont floodplain deposit.
From here, we will travel in a northwest direction through Shandaken, onto NY 23, then along NY 30 N past Grand Gorge to the Blenheim-Gilboa Power Station. On the trip towards Grand Gorge, we will be traveling on terrain mostly underlain by the Oneonta formation and have opportunities to view on our left, the valley of Schoharie Creek. The Schoharie is normally an underfit stream, although heavy rains during April, 1987 caused considerable flooding and erosion. The Blenheim-Gilboa Power Station, completed after World War II, employs waters of the Schoharie Creek, held in a main (channel-level) reservoir and an upper reservoir located on a plateau west of the Schoharie, to generate electricity for the Power Authority of the State of New York. A cluster of four stops in this area, which is essentially underlain by beds that are upper Hamilton and Tully equivalents, will include a visit to a sharply undercut slope in the Schoharie channel produced during the April floods, and a revisit to the Gilboa bridge, north of the Schoharie Reservoir. Near the bridge stand some of the stumps of the famous Gilboa Forest flora.
The return south through Grand Gorge and then eastward, will carry us to a unique exposure of the Oneonta formation, where we can be afforded the chance to examine a small, yet detail-packed outcrop, and discuss various ideas on the environment of deposition of these sediments. It is not a new outcrop, but apparently it is visited by geologists quite often, according to people living nearby, and this would seem to justify our return to it.
As we travel through Haines Falls to Tannersville, in a direction roughly perpendicular to the depositional strike (mean cross-bedding in this area near the Catskill Front has a vector of 297° according to Fletcher's 1967 paper), we will not be traveling "down-section" to any great degree. At Tannersville, we will turn towards North and South Lakes and stop at the edge of the Catskill Escarpment, nearly 2000 feet or about 700 meters above the Hudson Valley floor. Hopefully, we can reach this location before late afternoon. The view eastward, across the Hudson Valley to the Housatonic Mountains in the distance, is a grand vista. It should make any of us speculate on, and perhaps better understand the Acadian Mountains that were the high source terrain for the sediments that we revisited.
We hope that you will enjoy this trip, and rest secure in the comforting thought that there will be no examination at the end of the trip!

STOP 1. Bakoven Shale.
The black shale and overlying siltstone section in the high road cut across the road area well described by Pedersen et al. (1976, Stop 7) and appear to represent the upper part of the Bakoven formation. This unit may represent initial deposition of a delta toe in a deep distal basin.

Mountain Marion escarpment and Esopus floodplain
Proceed along base of Mountain Marion escarpment (on right) with Esopus floodplain (bottom of glacial lake) on left.

STOP 2. Base of Mount Marion Escarpment.
Observe the variation in lithology, sedimentary structures, and fossils or lack of them. Can you find any reason for postulating the advance of a delta into the Bakoven basin such that these sediments represent deposition on a distal to proximal prodelta slope? Many blocks of Mount Marion, some quite large, have rotated with slow gravitational descent to give erroneous impressions of bedding plane attitudes along the escarpment.

Increasing sandstone bed frequency and thickness
We have been ascending up section and for the next 0.9 miles will note increasing sandstone bed frequency and thickness in the road cuts and nearby outcrops as we pass from Mount Marion to Ashokan beds.

'Slow Children' and Feral Dogs.
Close your windows and drive very slowly.

STOP 3. Quarry in Mt. Marion.
This quarry is probably in upper Mount Marion shales and siltstones. Fossils are exceedingly abundant in one horizon with articulate brachiopods and bivalves most abundant but many other types of fossils also occur. Some of these are very small and some are exceptionally large - especially two inarticulate brachiopods, Roemerella grandis and Lindstroemella aspidium.
Sheets of illustrated fossils will be passed out to help you identify your discoveries. A mug-shot of the fractal-like trace fossil Aristophycous will also be distributed. This specimen, obtained from this quarry, appears to be the only Devonian find recognized and is currently in private hands. Please help us find the other half of this specimen or another equally well-preserved. The specimen appears to have come from within six inches of the glaciated pavement at the north end of the quarry. Sandstones, possibly representative of the Ashoken formation, can be seen across the road to the west. The strata in the quarry may represent sediments deposited on the shallow, marine shelf of an advancing delta marine platform. The Ashoken sands may represent further shelf advance as intertidal shelf deposits.

At some point in the next 1.6 miles we will pull off highway and park on right.

STOP 4. Plattekill Formation.
In these 1.6 miles there are many good road cuts where the red and green sandstones and shales of the Plattekill formation can be seen. Look for lithologic changes and sedimentary structures which might indicate a piedmont floodplain environment.

STOP 5. Blenheim-Gilboa Power Station.
Hidden in the Schoharie Valley at this location, and designed to blend in with the natural landscape is one of six power stations operated by the New York Power Authority. The facility is located on the Lansing Manor Estate property, and the Lansing Manor Museum, housed in the 19th Century Manor House is nearby. A dam has been built to block the north flowing Schoharie Creek. Water is recycled between the lower reservoir and an upper one located on Brown Mountain to the east. The substation on the east side of the lower reservoir is not easily recognized from the visitors' center here, and the upper reservoir can not be seen at all. During times of high power demand, water is released from the upper reservoir to drive four turbine generators. Flow of Creek water northward beyond the dam is measured to match water intake into the lower reservoir whenever possible. The Creek here is underlain most likely by the Potter Hollow formation. The visitors' center contains a small museum that includes rock samples and one or two tree stumps.

STOP 6. Mine Kill Falls Overlook.
This is in part of a recreational site located just south of Lansing Manor. We will stop briefly here. At the north end of the parking lot we can view waterfalls of the Mine Kill as it flows eastward into the Schoharie Valley. The Manorkill formation overlies Potter Hollow gray and red beds, but the contact cannot bee seen from the observation platforms.

STOP 7. Erosion in Bend of Schoharie Creek.
This location is at a sharp bend in the Schoharie at the base of Bernt Hill, in marine facies of the Manorkill formation. Heavy rains during April, 1987 resulted in severe flooding of the Schoharie that caused much erosion in several places, sometimes undercutting nearby roads. This is what we see here on the west side (undercut slope) of the bend. Moderate gullying also developed on the opposite (far) side of the road in this area, but road crews have repaired most of the damage. Please watch your step, and do not walk too close to the edge of the rock ledges.

STOP 8. Tree Fern Trunk Display.
A well known display, about a half dozen stumps that are identified by Banks et al. (1985) as progymnosperms which represent typical remains of the Gilboa Forest, uncovered during quarrying operations near here. The trees probably grew to a height of about 60 feet (18 meters), and the specimens we see are mostly Eospermatopteris. The stumps were found in the lower Manorkill beds (and upper Potter Hollow?), which are assigned to the upper Hamilton Group. Although we will not make the attempt, a trek across the bridge and then southward along the Schoharie Channel leads to the east side of the Schoharie Reservoir (see Figure 3), where, during times of lower water levels, cross-bedding and occasional molds of small stumps may be seen in the light gray sandstone near the water's edge.

STOP 9. Fluvial Facies (?) Red Beds.
NO ROCK HAMMERS, PLEASE! This small outcrop is unique in terms of what it has to offer in one package. It consists primarily of three lithologic divisions in a coarsening-upwards sequence with distinct cross-bedding in the uppermost unit, and a small channel cutout on the left (west) side of the outcrop. The top surface of this rock exposure shows a top view of the cross-bedding structures, and a glacially smoothed and striated surface. Buttner (1977) referred to this outcrop as possibly representing a transitional facies (we assume transitional between meandering and braided fluvial systems). What interpretation can you obtain from this outcrop? (Oneonta formation here.)

STOP 10. Catskill Escarpment.
NO ROCK HAMMERS, PLEASE! Site of Catskill Mountain House. Although Figures 4 and 5 show details of topography and stratigraphy of the Catskill Clastic Wedge and the Catskill Front respectively, we feel that Figure 71B on page 139 of Dunbar and Rodgers (1957) is unexcelled in depicting lithologic boundaries, and the Catskill facies crossing time lines, in a simple yet effective way. We are on the very edge of the escarpment, and Palenville is about 1700 feet (520 meters) below us, while the Hudson River farther to the east is at a level that is about another 165 meters lower. We can easily see (hope for a clear day) the Rowena Memorial School Building, built in 1899 in Palenville, and made of Becraft limestone (Helderberg Group). The Catskill Mountain House was a resort hotel first built here in the early 1800's, and enlarged over the decades to become one of the most notable vacation sites in the East. After the turn of the century, its popularity began to decline somewhat, and reportedly, the steel rails used for conveying passengers by a train system up to the level of the escarpment were torn up and scrapped for the war effort in World War I. Although there were changes of ownership, the hotel continued to serve tourists until the late 1940's. By the late 1950's the building was judged to be beyond repair, and on a pre-dawn winter morning in the early 1960's, it was set afire by State authorities. Whatever part of the wreckage that could not be removed was pushed over the escarpment to the slopes below. Today, the view to the east is as spectacular as it was for hotel guests who sat on the front porch which was located very near the edge of the escarpment. At this location during late Devonian time, there was perhaps another mile of sediments above us. Projecting, in our minds, the trend of these sediments upward to the east as we view the present Housatonic Mountains beyond the Hudson River, we can begin to comprehend the elevation of the Acadian Mountains source terrain. Red bed sandstones and conglomerates with much cross-bedding evident, can be seen along the escarpment here.

JAMES F. OLMSTED
EDITOR
HOSTED BY:
THE CENTER FOR EARTH AND ENVIRONMENTAL SCIENCES
AND
THE CENTER FOR LIFELONG LEARNING
STATE UNIVERSITY COLLEGE
PLATTSBURGH, NEW YORK
Upon recalling my first thoughts of a teaching job at SUNY at Plattsburgh two impressions seem to have been important to me. One was the prospect of living in a pleasant place with interesting landscape and variable climate and secondly some interesting geology at the doorstep. Someone who considers himself a field petrologist is certain to be impressed with the notion of living and teaching with the Green Mountains a few miles to the east and the Adirondacks nearby in the other direction. Those thoughts could not begin to represent the richness and variety of the geology and its history to be found in the Champlain Valley. The fact alone that this college is hosting the NYSGA for the second time in less than twenty years is evidence of the interest in the geology of the Lake Champlain region.
All of the trips that are offered here reflect work that has been accomplished within the last ten years. Many of these works include efforts of students who have surely benefitted greatly as have the authors and, we hope, so will you. That this region continues to be a spectacular geological laboratory is supported by the variety of descriptions included herein.
I would like to thank all of those who contributed to this volume, in particular Dave Franzi who personally prepared much of two of the trips and solicited another and helped me in many other ways. Thanks is also due to Carolyn Turner who assisted with some of the typing and to Dave Lawrence who supervised production of the volume. Thanks is also due to the other faculty in the CENTER who helped in many ways and to Yngvar Isachsen who provided the cover design. Finally recognition is due to Tom Wolosz of our department, current NYSGA president and to Kate Chilton of the Center for Lifelong Learning, Plattsburgh State who ran the meeting. One does not have to read very far to realize that a number of important conclusions are reported here. The authors are to be commended, and I also wish to thank them here.
Finally that this is the SIXTIETH annual meeting of this organization attests to the vitality of the NYSGA and of geology as a profession in New York State. In reviewing previous guidebooks I am impressed with them as a resource of geological literature for New York and adjacent areas. The NYSGA provides important academic and professional service to the region and truly deserves this recognition.

A1:ASPECTS OF THE GLACIAL GEOLOGY OF KEENE AND LOWER AUSABLE VALLEYS, NORTHEASTERN ADIRONDACK MOUNTAINS, NEW YORK
JOHN A. DIEMER
Department of Geography and Earth Sciences
University of North Carolina at Charlotte
Charlotte, NC 28223
DAVID A. FRANZI
Center for Earth and Environmental Science
State University of New York at Plattsburgh
Plattsburgh, NY 12901
The existence of Late Quaternary proglacial lakes in the Adirondacks has long been suspected (Taylor, 1897; Kemp, 1898; Ogilvie, 1902; Alling, 1916, 1919; Denny, 1974; Craft, 1976; Gurrieri, 1983; Diemer, et.al., 1984; Gurrieri and Musiker, 1988). Sedimentary deposits interpreted as dropstone-bearing varves and landforms interpreted as incised outlet channels, deltas and wave-formed beaches have been used as evidence for the existence of these intermontane proglacial lakes. On this trip, we propose to document some of these features in Keene and lower Ausable Valleys of the northeast Adirondacks. We will also discuss some constraints on the history of deglaciation of this region. Much work on the glacial geology of the northeast Adirondacks remains to be done and we hope you find this trip to be provocative.
FIELD AREA
Keene Valley extends northward 35 km (22 mi) from St. Huberts to Au Sable Forks (Figure 1). Waters from the Upper and Lower AU:sable Lakes feed the East Branch of the Ausable River which flows northward through Keene Valley. The elevation of the valley floor is 340 m (1117 ft) at St. Huberts (Figure 2), 254 m (833 ft) at Keene (Figure 3), and 170 m (558 ft) at Au Sable Forks (Figure 4). The West Branch of the Ausable River originates to the south of Lake Placid (Figure 1). It drops in elevation from 488 m (1600 ft) to 305m (1000 ft) as it flows through Wilmington Notch. At Haselton (Figure 5), the elevation is approximately 254 m (832 ft) . The confluence with the East Branch of the Ausable River is at the town of AuSable Forks. Below the confluence, the Ausable River flows east-northeast for 25 km (15.5 mi) through the lower Ausable Valley and empties into Lake Champlain (elevation 29 m (95 ft)) at Ausable State Park. · The mountains bordering Keene Valley are highest at the southern end (e.g. Giant Mountain to the east of St. Huberts is 1410 m (4627 ft)) and decrease in elevation northward (e.g. Bald Mountain southeast of Au Sable Forks is 652 m (2139 ft) (Figure I)). Major cots along the drainage divides separating Keene Valley from adjacent watersheds occur along lineaments. Two prominent sets of lineaments trend approximately NE-SW and NW-SE. The elevations of the cols decrease north ward.

A1: ASPECTS OF THE GLACIAL GEOLOGY OF KEENE AND LOWER AUSABLE VALLEYS, NORTHEASTERN ADIRONDACK MOUNTAINS, NEW YORK

STOP 1. Norton Cemetery
The borrow pits in the eastern part of the Norton Cemetery terrace contain stratified sand and gravel deposits. In the lower parts of the pits, horizontally stratified, trough cross-stratified and cross-laminated fine to medium sands in bedsets decimeters thick are common. Soft sediment deformation features are locally abundant. The terrace deposit coarsens upward to trough cross-stratified and channelized sands and gravels. Channels are decimeters to a meter or so deep and meters wide. Channels are filled with either stratified or massive sands and gravels. Channel margins have variable dips including nearly vertical.
Near the top of the Norton Cemetery terrace deposit, a sharp erosion surface is overlain by trough and planar cross-stratified sands and boundary gravels filling small channels. The channels intercut and are decimeters deep and meters wide. A concentration of boulders occurs immediately above the sharp erosion surface. Rounded, laminated, mud clasts occur locally both above and below the sharp erosion surface (Figure 70).
The terrace deposits are interpreted as a upwardly coarsening delta deposit. The lower part of the sequence consists of delta foreset beds with subaqueous channels, partly filled by sediment gravity flow deposits, at their upper ends. Steeply dipping channel margins may be due to channel incision into a frozen substrate. The prominent erosion surface is interpreted as the contact between delta foreset and fluvial topset beds. The trough and planar cross-stratification above the erosion surface are interpreted as the product of deposition by migrating dunes and small bars. The abundant intercutting channel forms an~ bar remnants suggest a braided stream origin. Rounded, laminated mud clasts are interpreted as either reworked, higher-level, lacustrine rhythmites or as floodplain muds.
A second locality at Stop 1 is at the end of the access road to Norton Cemetery. The access road to the south of the cemetery entrance has been closed as a result of slumping. In the landslide scar, climbing ripple cross-laminated very fine sand with abundant mud drapes can be seen. The bedding has been disturbed, either by soft-sediment deformation or by road construction. These sediments are the lowest accessible terrace deposits and are interpreted as the distal portion of delta foresets. A spring line marking the contact with underlying interlaminated muds and clays (rhythmites) is located a few meters downslope. The rhythmites are centimeter-scale ·and interpreted as lacustrine deposits formed in a setting close to a sediment source (i.e. a side valley tributary). Hence the rhythmites are interpreted as delta toeset beds.

STOP 2. D.O.T. Sand And Gravel Pit, Keene, N.Y.
The Department of Transportation operates a sand and gravel pit 1 km to the south of Keene, N.Y. The sediments are composed of stratified sands and gravels interbedded with diamictons. Grain size ranges from sand to boulders in both the stratified gravels and the diamicton. These sediments are interpreted as ice-contact glacial outwash in origin.

STOP 3. Rhythmite Sequence At Haselton, N.Y.
The sediments at Stop 3 are composed of a diamicton overlain by a rhythmite sequence. The diamicton contains boulders as large as 1 meter (Figure 8A). The top of the diamicton has decimeters of relief and is conformably overlain by millimeter to centimeter thick interlaminations of mud and clay (rhythmites). Dropstones are common (Figure 8B). The rhythmites are typically horizontally bedded, but may be locally deformed (Figure 8C). In places, rhythmites arc interbedded with cross-laminated sands which have sharp basal contacts and grade upward to asymmetrical ripple forms draped by mud laminations (Figure 8D). The sediments at this stop are interpreted a s glacial till or debris-flow deposits at the base (diamicton), overlain by lacustrine sediments (rhythmites). The rhythmites may have accumulated in a setting distant from a sediment source as they are fine grained. The interbedded cross-laminated sand layers may be due to turbidity currents. The deformed bedding may be a result of soft-sediment deformation on a low slope.

STOP 4. Black Brook Sand Plain
The Black Brook sand plain is a terraced accumulation of stratified drift at the distal end of a bedrock gorge north of the village of Black Brook. The surface of the sand plain is roughly triangular in map view and ranges in elevation from 329 m (1080 ft) at the mouth of the gorge to 275 m (902 ft) at the West Branch of the A usable River.
The exposures in a gravel pit 0.64 km (0.4 mi) east of Black Brook contain meter-scale beds of coarse sandy gravel to boulder gravel (Figure 9). The working face of the pit is oriented east-west and is approximately 40 m (130 ft) long and 4 to 6 m (13 to 20 ft) high. The surface elevation of the sand plain at this location is approximately 315 m (1 033 ft). The lower unit consists of horizontally stratified, and trough and planar cross-stratified sandy gravel, the base of which is obscured by slumping. The sandy gravel is overlain by a 2.0 to 2.5 m (6.6 to 8.2 ft) thick, massively bedded, very coarse boulder gravel layer. The gravel contains boulders over 1.5 m (5 .0 ft) in diameter, some of which are crudely imbricated. The gravel unit can be traced laterally across the working face of the pit. The gravel is overlain by 1.0 to 1.2 m (3.0 to 4.0 ft) of cross-stratified sandy gravel. The cross strata are centimeters to decimeters thick and commonly extend from the top to the bottom of the unit. Paleocurrent indicators indicate southward to southeastward flow throughout the section.
The Black Brook terrace deposits are interpreted as a fluvio-deltaic complex that was built into falling levels of preglacial lake in the lower Ausable Valley (Figure 10). Base level was probably controlled by the outlet channels in the vicinity of Colby, Sheep, Little, and Haystack mountains (outlet channels 5a, 5b, 5c, and 6, Figure 4).
The sand and gravel deposits at Stop 4 are probably glaciofluvial in origin and may represent deltaic topset beds. The sandy gravel facies probably represents fluvial deposition under near average meltwater discharges through the bedrock channel north of Black Brook. The boulder gravel facies is interpreted as a high energy, catastrophic flood deposit. Discharge of this magnitude may have been produced by the diversion of outflow from lakes in the Saranac Valley through the Black Brook channel (i.e. a limnic hlaup).

STOP 5. (Optional) Diamictons Near Ausable Forks
This stop includes roadside exposures along Ausable Drive, approximately 2.4 km (1.5 mi) southwest of Ausable Forks. The sediments consist of massive to crudely stratified diamicton with thin sand, gravel and silt interbeds. The diamicton beds are commonly decimeters to meters thick, light colored and have sandy matrices. The sandy interbeds are thin (centimeter-scale) and discontinuous and are either non-stratified or contain horizontal or ripple-drift laminations. The bedding is subhorizontal but may be deformed locally. These deposits probably accumulated in a ice-marginal, subaqueous environment.

STOP 6. Deltaic Deposits Near Clintonville
The gravel pit at Stop 6 is located on an extensive sand plain on the north side of the Ausable Valley between Clintonville and Ausable Forks (Figure 1). The surface of the sand plain slopes southward from approximately 204 m (670 ft) at its northern margin to 198m (650ft) near the Ausable River.
The lower portion of the pit contains approximately 5 to 6 m (16 to 20 ft) of southwardly dipping, fine to medium sand and sandy silt foreset beds. The bedsets are centimeters to decimeters thick and commonly contain horizontal laminations and ripple-drift cross-laminations. Thin silty deposits occur locally as draped laminae over ripple forms. The upper portions of the foreset beds are truncated and overlain by 1.0 to 1.5 m (3.0 to 5.0 ft) of horizontally stratified and trough and planar cross-stratified sand and gravel.
The sediments at the Clintonville gravel pit are interpreted as deltaic in origin. The erosional surface between the lower sandy facies and the upper gravel facies represents the contact between the subaqueous foreset beds and the fluvial topset beds. The elevation of the topset-foreset contact is approximately 198 m (650 ft) which indicates that deltaic sedimentation was graded to the level of Lake Coveville in the Champlain Valley (Denny, 1974). Southward-flowing meltwater streams from ice in the Little Ausable drainage basin north of Arnold Hill (Figure 1) provided much of the deltaic sediment in the eastern portion of the sand plain. The western portion of the sand plain was probably built by eastwardly flowing streams from the upper Ausable drainage basin. Southward drainage from proglacial lakes in the Saranac River Valley into the lower Ausable Valley via the Black Brook channel (Stop 4) may have contributed to delta construction near Ausable Forks (Denny, 1974).

STOP 7. Landslide Scar On The Ausable River At Keeseville
The section at Keeseville is exposed in a landslide scar on the south bank of the Ausable River at Keeseville. The river is deeply incised into deltaic terrace deposits which Denny (1974) correlated with Lake Fort Ann in the Champlain Valley. The surface elevation of the terrace is approximately 155 m (510 ft).
The base of the section consists of massive, compact, calcareous, gray diamicton with a silty to clayey silt matrix. The base of the diamicton is obscured by colluvium. The upper surface of the unit has a few centimeters of relief and is draped by 0.3 to 0.5 m (1.0 to 1.5 ft) of silt and clay rhythmites. The rhythmite sequence contains 11 silt-clay sediment couplets. The rhythmites are conformably overlain by approximately 6 m (20 ft) of fine to medium sand which coarsens upward to gravelly sand near the terrace surface. Spring sapping at the sand-rhythmite contact is responsible for slumping in the overlying sand unit.
The sediments at the Keeseville section record the ice recession from the mouth of the Ausable Valley. The diamicton is interpreted as a basal till and thus represents an interval of ice cover. The rhythmites are interpreted as varved lacustrine deposits that record the initial, deglaciation of the lower Ausable Valley and its subsequent inundation by Lake Coveville. The rhythmites, therefore, were probably deposited contemporaneously with the Lake Coveville deltas near Clintonville (Stop 6).
The overlying sandy deposits represent deltaic sedimentation by eastward flowing streams from the Ausable Valley into Lake Fort Ann. Regional lake level fell approximately 43 m (140 ft) in the Champlain Valley with the initiation of Lake Fort Ann. If the rhythmites are assumed to be Lake Coveville varves and the overlying sandy facies to be part of the Lake Fort Ann delta, then the time between the deglaciation of the mouth of the Ausable Valley and the initiation of Lake Fort Ann was about 11 years. The ice-front in the Champlain Valley may have receded northward to the mouth of the Saranac River at the time Lake Fort Ann was established (Denny, 1974).

Ausable Chasm

Surface of Champlain Sea delta (upper marine limit).

Surface of Champlain Sea delta (Port Kent Stage).

Entrance to Ausable Point State Park on the delta of the present Ausable River.

A2: GEOLOGY AND PETROLOGY OF MOUNTS JOHNSON AND ST.-HILAIRE, MONTEREGIAN HILLS PETROGRAPHIC PROVINCE
G. NELSON EBY
Department of Earth Sciences
University of Lowell
Lowell, MA 01854
The Monteregian Hills petrographic province consists of a group of small igneous intrusions and associated dikes and sills which lie along a more or less linear East-West trend extending from the Oka carbonatite complex located 30 km west of Montreal to Mounts Shefford and Brame 70 km east of Montreal. These plutons cut a number of terranes: the Precambrian Grenville, the St. Lawrence Lowlands, and the folded rocks of the Appalachian orogen. Mount Megantic lies 100 km east of Mounts Shefford and Brome and its assignment to the Monteregian Hills province is somewhat problematical. Petrographically and chemically Mount Megantic shows stronger affinities with the White Mountain igneous province than with the Monteregian Hills. On this field trip we will visit two plutons located in the central part of the province which are representative of some of the major magmatic trends in the Monteregian Hills.

A2: GEOLOGY AND PETROLOGY OF MOUNTS JOHNSON AND ST.-HILAIRE, MONTEREGIAN HILLS PETROGRAPHIC PROVINCE

STOP 1. Exposures Of Hornfels Collar
Walk up the trail to the base of the waste-rock pile. Along the trail are numerous exposures of the Lorraine siltstone, now metamorphosed to the hornblende hornfels facies. The hornfels dips northward into the intrusion with increasing steepness as the base of the waste-rock pile is approached.

STOP 2. Quarry In Pulaskite
Excellent exposures of the pulaskite are found in this small quarry. The strong vertical foliation is clearly evident in the quarry wall. Climb up through this quarry to a slightly larger quarry located at higher elevation. Note the increase in the amount of amphibole in climbing from the first to second quarry. The rock apparently grades from pulaskite to essexite.

STOP 3. Quarry In Rhythmically Layered Essexite
This quarry is located in the coarse-grained, layered essexite, that comprises the outer edge of the core series. Along the road leading into this quarry are outcrops of hornblende-rich essexite which are typical of the essexite found in the peripheral series. This hornblende-rich essexite contains sphene while the essexite in the quarry does not carry sphene. In the quarry are found excellent exposures of rhythmically layered essexite with cross-beds and trough-like structures. Climbing up out of the quarry note the disappearance of the rhythmic layering. Continue on to the summit. Note the decrease in grain size as the summit is approached.

STOP 4. Summit Of Mount Johnson
At the summit the fine-grain size makes it difficult to distinguish the foliation which was clearly visible on the climb from Stop 3 to Stop 4. With the exception of the presence of olivine, the essexite at the summit and in the quarry at Stop 3 is petrographically and chemically identical. To the north of the summit is found an arcuate body of coarse-grained, amphibole-rich essexite. On a clear day the summit of Mount Johnson provides an excellent view of the Monteregian Hills. Return by the same route to the parking lot. It is once again worthwhile to look at the rocks to see if it is possible to distinguish any clear breaks between the various petrographic units.

STOP 5. Camptonite Dike
Turn right out of the parking lot and continue northwesterly along the road to a lamprophyre dike cutting the Lorraine siltstone. Park on the west side of the road. The dike trends north-south along the western margin of Mount Johnson . It is of somewhat older age than the main pluton but may be petrogenetically related to the Mount Johnson magmas. The dike consists of phenocrysts of titanaugite, partly altered to a mixture of green amphibole, brown biotite and chlorite, and kaersutite in an intergranular groundmass of plagioclase, biotite, kaersutite, opaques, apatite, and trace sphene.

STOP 6. Exposures Of Igneous And Diatreme Breccias
Proceed north along the main trail which follows the valley between the two halves of the mountain. Pass Lac Hertel. On the left (west side) of the trail are scattered outcrops and boulders of both the igneous and diatreme-like breccias. Most of the lithologies of the pluton can be found as blocks and fragments in these breccias.

STOP 7. Gabbros And Diorites Of The Sunrise Suite
Retrace your path southwards to the intersection with the Pain de Sucre trail. Proceed up this trail (west) towards the summit of Pain de Sucre. Outcrops of gabbro and diorite of the Sunrise suite are exposed along this trail. In places the rocks are extremely coarse-grained and outcrops are found to carry clots of large radiating amphiboles. Foliation is generally poorly developed in this part of the suite.

STOP 8. Nepheline Diorites And Monzonites Of The Pain De Sucre Suite
Continue on to the summit of Pain de Sucre. In the immediate vicinity of the summit is an almost continuous exposure of relatively leucocratic coarse-grained rocks of the Pain de Sucre suite . The rocks usually have a bluish cast and visible laths of alkali feldspar. Olivine is present locally and nepheline occurs as an interstitial phase.

A3: FORELAND DEFORMATION AS SEEN IN WESTERN VERMONT
Rolfe S. Stanley
Burlington, Vermont, 05405
Western Vermont is underlain by three distinctive sequences of rocks that range in age from Late Proterozoic to Middle Ordovician and are typical of the western part of the Appalachian Mountains. The lowest most sequence, which rest with profound unconformity on the Middle Proterozoic of.the Green Mountain and Lincoln massifs, largely consists of metawackes, mafic volcanic rocks and phyllites that represent a rift clastic sequence. These rocks grade upward into siliciclastic and carbonate rocks of the platform sequence which in turn are overlain by Middle Ordovician shales of the foreland basin sequence. The boundary between the two sequences is the based of the Cheshire Formation (fig. 1 ). North of Burlington, Vermont the platform sequence grades into shales, breccias and conglomerates of the ancient platform margin and eastern basin. These sequences have been studied by a number of workers in the past (Cady, 1945; Cady and others, 1962; Hawley, 1957; Erwin, 1957; Welby, 1961; Stone and Dennis, 1964i for example) and are receiving current attention by Mehrtens (1985, 1987) and her students (Gregory, 1982; Myrow, 1983; Teetsel, 1985; Bulter, 1986; MacLean, 1986, 1987). Agnew (1977), Carter (1979), Tauvers (1982), DiPietro (1983) and Dorsey and others (1983) have reexamined parts of the rift clastic sequence while Doolan and his students are currently working in the same sequence in northern Vermont and Quebec (Doolan and others, 1987; Colpron and others, 1987). Figures 1 and 2 illustrate the representative stratigraphic columns for western Vermont north of the latitude of the Lincoln massif where the field conference will be held. Additional information can be found in Welby (1961) and Doll and others (1961 ).
The structure of western Vermont is dominated by major, north-trending folds and imbricate thrust faults which are we ll d i s p 1 aye d on the G e o log i c Map of Vermont ( Do 11 and others, 1961). The rift clastic and platform sequences have each been displaced westward on major thrust faults that extend through much of Vermont. The larger of the two, the Champlain thrust, extends from southern Quebec to Albany, New York and places the older platform sequence over the younger foreland basin sequence. Estimates of westward displacement range from 15 km to 100 km. The smaller of the two, the Hinesburg thrust, places transitional and rift clastic rocks over the platform sequence and as such forms a boundary between the synclinorial rocks of western Vermont and the the Taconian Orogeny. This conclusion is based on regional considerations (Stanley and Ratcliffe, 1985) and the analysis of available isotopic data (Sutter and others, 1985). Mesozoic deformation in the form of extensional faults and igneous activity clearly affected the region (McHone and Bulter, 1984; Stanley, 1980). Available evidence, ho we ver, can not rule out limited Acadian or even Alleghenian deformation.
Participants of this field trip will see the change in structure and fabric as they cross the foreland from South Hero Island to the western margin of the hinterland at the Hinesburg thrust fault at Mechanicsville, Vermont.

STOP 1. West Shore of South Hero Island.
This stop illustrates the low level of deformation that characterizes much of the west shore of the Champlain Islands and the eastern shore of New York in the area of Plattsburgh. Local areas of moderate deformation, however, do exist where bedding plane faults and high-angle faults cut the bedrock. These outcrops of shale and thin micrite beds are in the Stony Point Shale. Note that the bedding, which is nearly horizontal, is cut by a poorly developed cleavage that is only developed in the shale beds. The cleavage dips very gently to the east and is interpreted to result from simple shear parallel to the bedding. Thin layers of calcite are present on some of the beds. Those layers that are marked by prominent slickenlines are bedding plane faults. As we will see at other outcrops today, the larger faults are marked by thicker layers of lineated calcite.

STOP 2. Lessor 's Quarry
This quarry is located in the fossiliferous Glens Falls Limestone. The quarry contains some of the finest evidence of pressure solution in western Vermont. The cleavage (S1), which is discontinuous and wavy, is a classical pressure solution feature with well developed selvedges that truncate fossils and offset bedding. A small anticline at the south _edge of the quarry contains adjustment faults at its hinge that end along cleavage zones with thick clay selvedges.
The major structures in the quarry are bedding-plane thrust faults. These faults are marked by calcite layers with west-trending slickenlines and a fault - zone cleavage (St).
Near the larger faults the S1 cleavage is rotated (Sr) toward the plane of the fault. Note that both St and Sr dip gently to the east and indicate that movement on the bedding faults was to the west. The St cleavage forms as a result of simple shear on the faults. The anticline along the south wall and edge of the quarry is formed from a small duplex. Unfortunately, the best evidence for this duplex has been excavated.
On the northeast side of the quarry (fig. 6) a syncline and an associated blind, synformal thrust fault are truncated by the major thrust fault that is continuous across the north wall of the quarry. The origin of this structure is not clear, but it is thought to be associated with a duplex or ramp below the level of the quarry floor.

STOP 3. "The Beam"
This is a superb outcrop that serves as a field laboratory for research and teaching of foreland deformation. Please study it. Use your cameras but not your hammers.
The outcrop is located in the Cumberland Head Formation approximately 5 miles (8 km.) west of the exposed front of the Champlain thrust fault or approximately 4600 ft. (1400 m.) below the restored westward projection of the thrust surface. The major questions that will be discussed are: 1. How do ramp faults form?, 2. Are there criteria to determine if imbricate thrust faults develop toward the foreland or hinterland?, 3. What is the relation between faulting and cleavage development?, 4. What processes are involved in the formation of fault zones?, 5. Are there criteria that indicate the relative importance and duration of motion along a fault zone?, 6. Is there evidence that abnormal pore pressure existed during faulting?, and finally 7. What is the structural evolution of the imbricate faults? The first six questions will be largely addressed by direct evidence at the outcrop. The last question will be answered by palinspastically restoring the imbricated and cleaved sequence to its undeformed state (fig. 9).
THE OUTCROP
Five imbricate thrust faults and associated ramps are exposed in profile section in a foot thick bed of micrite that extends 14 m along an azimuth of N 80 E (fig. 7a). The imbricate fault can be further classified as a central duplex of three horsts that are separated from two simple ramps at either end of the outcrop by approximately 2. 5 m of flats. The micrite bed is surrounded by at least 1.5 m of well-cleaved calcareous shale. Bedding plane faults are present along the upper and lower surface of the micrite where they merge with ramp faults that cut across the micrite bed at an angle of approximately 30 degrees. The lower bedding plane fault or floor thrust is relatively planar and the fault zone is thick compared to the upper bedding plane faults which are folded in the ramp areas, cut by ramp faults, and the fault zones are thin. The upper bedding plane fault forms the roof thrust for the central duplex. Along the intervening flats the upper faults are generally planar although they are cut by the S1 cleavage in many places. The lower bedding plane fault is the major decollement across the outcrop. Older bedding planes faults are also present throughout the shale where they are offset by the penetrative S1 cleavage.
All the fault surfaces are covered by layers of sparry calcite that vary in thickness from several millimeters to 4-6 cm. The thickest zone is found along the decollement or floor thrust whereas the thinest zone is found along the older bedding plane faults in the calcareous shale (fig. 7a). In all but the thinest layers, the calcite is arranged in distinct layers that are separated by discontinuous selvedge of dark gray shale. Each of the layers are marked by grooves or slickenlines that trends N 56 W and are essentially parallel from layer to layer (7b). In sections oriented perpendicular to the layering and parallel to the slickenlines the shale selvedges are more parallel to each other than in sections cut perpendicular to the slickenlines where the selvedges either anastomose or conform to the cross section of the grooves. In the parallel sections, however, some of the selvedge layers are truncated by more continuous surfaces. One of these can be traced for 1.5 m or more along the decollement. At a number of places along the different fault zones small dikes of sparry calcite have intruded the lower part of the calcite-shale layers. The fault-zone fabrics are most clearly displayed along the decollement where the calcite-selvedge layers are more abundance.
Fractures are common throughout the micrite bed where they are oriented at either a high angle or low angle to the bedding. Most fractures are filled with sparry calcite. The most prominent fractures are arranged in en echelon arrays that climb either to the west or the east. Most of these arrays are located in ramps areas and along the west-facing limbs or small flexures. A few are present in the flat regions of the bed. The fractures in many of the arrays in the ramp regions are folded and some are cut by younger generations of en echelon fractures. In the eastern ramp the hanging wall and foot wall are cut by near-vertical fractures that are filled with fragments of the surrounding micrite embedded in sparry calcite so as to form clastic dikes.
Two, well developed, pressure-solution cleavages are present throughout the calcareous shale. The first and most conspicuous one, S1, strikes N 20 E and dips 60 to the east (fig. 7b). This orientation is an average based on measurements taken across the vertical face of the outcrop because the individual S1 surfaces are quite wavy along strike. As a result they form a distinct diamond - shape pattern on the bedding surface. The acute angle of the diamond pattern is approximately 30 degrees in the shale and 50 degrees in the micrite bed. This geometry indicates a moderate level of cleavage development according to the scheme of Alvarez and others (1976). S1 surfaces are covered by a black, carbon-rich selvedge of illite and kaolinite which is less than 0.5 cm thick. Although many of the cleavage surfaces are vertically continuous through the shale, some of them are short and discontinuous with tapered ends. The thickest selvedge occurs on the most continuous surfaces. The surfaces of the selvedge are not lineated although some are polished. The S1 cleavage offsets bedding and the older bedding-plane thrust faults with a down-to-the-east sense throughout much of the outcrop. This displacement is greatest where a selvedge is the thickest and it gradually is reduced to zero as a selvedge thins toward the tapered ends of the shorter cleavage surfaces. The average width of the microlithons between the S1 surfaces is 5.6 cm thick. The S1 cleavage not only cuts the older bedding-plane faults but cuts across most of the roof fault s on top of the micrite bed.
A second, well developed cleavage, St, is restricted to a foot-thick zone directly below the decollement (fig. 7a). The individual cleavage surfaces are thinner (about 1 mm thick), more closely spaced (about 1 cm or more), and are covered with a thin selvedge (less than 1 mm). Furthermore, St dips to the east at only 6 degrees compared to the steeper dip of S1. St is also developed along the roof thrust of the micrite bed, but the zone is thinner and it is more difficult to recognize because the roof faults have been folded in the ramp areas and deformed by S1. The St cleavage is definitely related to movement of the thrust faults because it is only found near the faults and it is absent away from them. In the zone near the decollement and the roof faults the S1 cleavage is rotated eastward so that the steeper 60 degree dip in the shale is reduced to 25 degrees (fig. 7b). The strike of the rotated S1 (hereafter referred to as Sr) is the same as S1 away from the faults. The counterclockwise rotation of S1 through an angle of shear of 35 degrees indicates that movement on the decollement was east-over-west along a direction of N 56 W as indicated by the slickenlines along the decollement. This sense of displacement is consistent with the orientation of St since the normal to St would correspond to the direction of maximum finite compressive strain.
Cleavage, similar to S1 and St, is totally absent from the micrite bed. In a few places, however, a very thin (less 1 mm), stylolitic to very irregular cleavage is oriented perpendicular to bedding in the micrite. This cleavage is not developed uniformly throughout the micrite. Where it is formed the cleavage surfaces are separated from each other by at least 6-10 cm. The form, orientation and limited distribution of this cleavage indicates that it formed very early in the deformation sequence while compression was essentially parallel to the planar micrite bed.

STOP 4. The Champlain Thrust Fault At Lone Rock Point, Burlington, Vermont -
The following discussion is reprinted from The Centennial Field Guide, Volume 5, of the Geological Society of America in 1986. All the figure numbers for this stop refer to those figures in the reprint. The reprinted discussion appears in Appendix 1. Figure 10 is a regional map showing the location of the Champlain thrust fault in 'western Vermont. The Long Rock Point locality is identified as "LRP". The Arrowhead Mountain thrust fault is located east of the Champlain thrust fault and is identified by the letters "AMTF".

STOP 5. The Hinesburg Thrust Fault At Hinesburg, Vermont
This is the classic and best exposed locality for the Hinesburg thrust fault (fig. 10, "HTFM"). It contains many fault related fabrics that have recently been studied by Strehle (1985) and published by Strehle and Stanley (1986) in a bulletin of the Vermont Geological Survey (Studies in Vermont Geology No.3). This publication also contains analyses of other fault zones of western Vermont which will not be seen during this conference. The reader is referred to this paper or an earlier NEIGC trip by Gillespie and others (1972).
The Hinesburg thrust fault separates the Cambrian-Ordovician rocks of the platform sequence from the older, highly deformed metamorphic rocks of the eastern hinterland. As shown in figure 4, the Hinesburg thrust fault developed along the overturned, sheared limb of a large recumbent fold. This fault probably broke out from the overturned limb of a fault-propagation fold (Suppe, 1985) and therefore is similar in origin to the Arrowhead Mountain thrust fault. To the south the Hinesburg thrust fault dies out somewhere in the overturned limb of the Lincoln massif (Tauvers, 1982; DiPietro, 1983; DelloRusso and Stanley, 1986).
At the Mechanicsville locality the lower 40 m. of the Cheshire Quartzite is structurally overturned along the base of the upper plate of the Hinesburg thrust fault. Higher up the cliff the quartzite grades into the Fairfield Pond Formation of Tauvers (1982). The lower plate rocks, which are poorly exposed, consist of carbonates of the Lower Ordovician Bascon Formation. Slivers of dark gray phyllite of the Brownell Mountain Phyllite are found at several localities along the fault trace. Chlorite, muscovite, and stilpnomelane are present in the quartzite. Muscovite and chlorite are present in the schist. Quartz is thoroughly recrystallized, but feldspar grains are fractured and bent. The following features should be studied here:
1) The change in fabric as the fault surface is approached. The quartzite grades from a protomylonite away from the fault to an ultramylonite near the fault. In thin section quartz becomes finer grained and quartz porphyroclasts decrease in number toward to fault.
2) The presence of east-over-west or "S" shaped asymmetrical folds. These folds are related to simple shear along the fault and are not related to the overturned limb of the older Hinesburg nappe. Parasitic minor folds related to this older structure would show a west-over-east or "Z" shaped asymmetry.
3) The prominent compositional layering. This layering is not bedding but represents the axial surface schistosity of the older parasitic folds related to the Hinesburg nappe. It is overprinted by a younger schistosity that is associated with the east-over-west folds. These two schistosities become a composite mylonitic schistosity as the fault surface is approached.
4) The prominent mineral lineation consisting of elongate quartz and quartz clusters.
5) "Z" shaped quartz veins that are associated with beds of quartzite. These structures are particularly interesting because the record progressive shear strain and mylonitization along the fault. The veins are confined to the metasandstone and metasiltstone layers and occur in at least 3 orientations. The least deformed veins are oriented either perpendicular to the layering or dip steeply to the west. They are filled with straight quartz fibers oriented perpendicular to the vein walls and show no signs of recrystallization except where they cross older "Z" shaped veins (Warren, 1988, pers. comm.). Here the fibers are reduced to smaller, nearly equant grains with undulose extinction. The most deformed veins are "Z" shaped and dip to the east. The older quartz fibers are completely replaced by fine grained, recrystallized quartz that forms a mylonite with distinct whitish layers oriented essentially parallel to the vein boundary. The third set is intermediate in orientation and deformation between the other two. The "Z" pattern develops because the shear strain (8.5 or an angle of shear of 84°) is higher in the pelitic units that surround the metasandstones where the shear strain is 1.48 (angle of shear of 56°). Strehle and Stanley (1986) suggested that these veins developed as shear fractures during east-over-west shear. This interpretation is not consistent with the fact that the youngest veins are vertical and consist of quartz fibers orientated essentially parallel to the layering (Warren, 1988, pers. comm.) It therefore appears that the veins formed as extension fractures during periods of vertical or near vertical loading. These periods of flattening (pure shear) were then followed by longer periods of east-over-west simple shear during which the veins were rotated westward and the characteristic "Z" pattern developed. The quartz, which was originally fibered, became progressively mylonitized as the extension veins were rotated into the favorable, east-dipping, shear position. Movement on these east-dipping veins continued even after they were cut by younger, unrotated veins because the fibered segments of the younger veins are deformed and recrystallized.
6) Rare west-dipping shear bands. These structures deform the younger schistosity which is parallel to the axial surfaces of the "s" shaped folds.
7) Westward displacement (N 75 W) of the upper plate of the Hinesburg thrust is documented by "s" shaped folds, "Z" shaped-quartz veins, quartz porphyroclasts, and late shear bands.
8) Late fractures and associated en echelon fracture arrays. These structures thought to be related to Mesozoic normal faults which cut the Champlain and Hinesburg slices. One of these faults is located about 1000 m. directly west of this locality.
The interpretation of these structures and the thin sections fabrics are discussed in Strehle and Stanley (1986).

A4: THE CAMBRIAN PLATFORM AND PLATFORM MARGIN IN NORTHWESTERN VERMONT
Charlotte J. Mehrtens
Burlington, Vt. 05405
The stratigraphy of northwestern Vermont is dominated by sedimentary rocks of the Cambro-Ordovician platform and basin sequence, which is part of an extensive belt of similar facies extending from Newfoundland to Alabama. These facies consist of carbonate and siliciclastic deposits characteristic of a shallow water platform, bordered to the east by a basinal sequence of shales and sedimentary breccias. Rodgers (1968) recognized this platform to basin transition as the margin of the Lower Paleozoic platform in eastern North America.
Cambro-Ordovician sediments were deposited on a passively subsiding shelf following late Precambrian rifting. These sediments accreted at a rate which kept pace with thermal subsidence as the shelf assumed the morphology of an accretionary rimmed platform during the Lower Cambrian. Examining the distribution of facies comprising the shallow water platform indicates that the interior regions were affected by tidal and wave processes whereas the shelf margin regions were subtidal and wave reworked (Gregory, 1982; Butler, 1986; Rahamanian, 1981; Myrow, 1983; Chisick and Friedman, 1982; Braun and Friedman, 1969). The adjacent deeper water basins accumulated talus, debris flows, and turbidites composed of detritus shed off the platform (Mehrtens and Dorsey, 1986; Mehrtens and Borre, 1987; Mehrtens and Hillman, in review).
The Cambro-Ordovician sequence in northwestern Vermont is unique in that the platform to basin sequence is intact and undisected by faults. Looking at the Cambro-Ordovician sequence throughout the Appalachians, only Pfeil and Read (1980) describe a platform to basin sequence, but it has been dismembered by faults and cannot provide information on the original geometric relations on the platform.
This field trip guide describes the facies and evolution of a portion of the Cambro-Ordovician carbonate platform in northern Vermont (Figure 1). The Cheshire Quartzite is the basal unit in the sequence (Figure 2), overlying Eocambrian rift-related sediments of the Pinnacle and Fairfield Pond Formations (Tauvers, 1982), and it will not be examined on this trip. The Cheshire is in gradational contact with the overlying Lower Cambrian Dunham Dolomite (Myrow, 1984), a carbonate unit which records sedimentation in peritidal, subtidal and platform margin environments (Gregory, 1982). The facies distribution and paleogeography of the Dunham Dolomite influenced the platform geometry and evolution in subsequent Cambrian deposits, consequently it will be examined in detail.
Overlying the Dunham Dolomite is the lower Middle Cambrian Monkton Quartzite, a mixed siliciclastic/carbonate unit which also records tidal flat to platform margin sedimentation (Rahmanian, 1981). The Middle Cambrian Winooski Dolomite has not been studied in detail, but a review of sedimentary and biogenic structures suggests that it also records peritidal to platform margin environments of deposition. The Upper Cambrian Danby Quartzite overlies the Winooski and contains a diverse suite of sedimentary structures documenting tidal flat, shallow subtidal, and platform margin environments, with significant storm overprinting (Mehrtens and Butler, in review).
This field trip will look at each of these units and examine evidence for their interpretation as shallow water platform deposits. The trip will also examine one basinal unit, the Rockledge Formation (Upper Cambrian). The Rockledge Formation is a limestone-clast conglomerate unit with associated massive sandstones and laminated siltstones interpreted to represent high and low density turbidity currents (Mehrtens and Hillman, in review).

A4: THE CAMBRIAN PLATFORM AND PLATFORM MARGIN IN NORTHWESTERN VERMONT

STOP 1. Abandoned quarry on the north side of Rt. 2
Park on the southwest (right) shoulder, cross Rt 2, and ascend overgrown driveway into quarry. The Champlain Thrust floors the quarry as the Dunham Dolomite is emplaced on the Middle Ordovician Stony Point Shale. The Dunham Dolomite exposed here is the basal facies of the Dunham, characterized by the rhythmic interbedding of dolomite (white) and silty dolomite (pink). This bedding style is interpreted to be the result of alternating sedimentation in a tidal flat setting, producing "ribbon bedding". Look for: undisturbed horizons of the dolomite and silt-rich dolomite, horizons of intraclasts, burrows, and cryptalgalaminites. Note that many of the clasts show rips and tears in their margins, others are bent. Many clasts are cored by calcite. Greiner (1982) recorded occurrences of gypsum in this facies in subsurface cores.

STOP 2. Shallowing-up cycles in the Dunham
This roadcut on the left (north shoulder) exposes 3 shallowing-up cycles within the Dunham. They are recognizable in the large roadcut because of the characteristic pink and white ribbon bedding of the peritidal caps of the SUC's. One SUC can be studied in detail on the northwest corner of the roadcut. The SUC (Figure 4) is composed of a basal subtidal dolomite overlain by the ribbon bedding of the peritidal cap. The cycles in the Dunham are similar to "muddy shallowing-up cycles" of James (1983) and they consist of 6-10 meters of bioturbated, sandy dolomite passing up into ribbon-bedded dolomite and silt-rich dolomite and local intra-formational conglomerate. What is the origin of the sand within the Dunham subtidal muds? SEM work led Gregory (1982) to suggest that frosting micro-textures on quartz grains recorded an eolian history to the sediment. However, channels within the Dunham are sand-filled, and provide a mechanism for the transport of sand across the platform. This is similar to the tidal channels of Shark Bay, western Australia, where channels are infilled with a mixture of carbonate mud and quartz sand from eroded Pleistocene bedrock.

STOP 3. Dunham subtidal and platform margin facies.
Pull off about 100 yards beyond the speed limit sign on this long roadcut. At the base of this outcrop (west end) there are good exposures of the subtidal facies of the Dunham with the characteristic mottled texture, thought to be produced by burrowing. Burrow mottles are irregular in shape, 1 to 8 cm in diameter, and lack sand. The segregation of siliciclastic material is one property that implies bioturbation produced this mottled texture. Between the white burrows the red matrix is very clay and sand-rich, and Stone and Dennis (1964) attribute this color variation to differing concentrations of trace metals. Specimens of Salterella conulata (Mehrtens and Gregory, 1983) were found in this facies. The platform margin facies is exposed on the east end of the same outcrop. This facies is composed of chaotically bedded, laterally discontinuous horizons of breccia in a sand-rich dolomite matrix. Clast composition is highly variable, and includes chert pebbles, sandstones, sandy-dolostones, and dolomitic sandstones. Breccia beds are structureless and very poorly sorted. Graded beds of sandstone are also present.

STOP 4. Monkton Quartzite, subtidal and shelf edge facies
This roadcut exhibits the subtidal and shelf edge facies of the Monkton, as evidenced by the overall thickness of the individual beds, increasing amounts of shale between sandstone beds, presence of relict oolites in some dolomite horizons, and occurrences of large scale tabular cross stratification. Many of these beds probably represent shelf edge sand shoals. Note characteristics of the Monkton here for comparison to the shallower-water deposits seen at Stop 6.
Walk east 0.3 miles to the small knoll beyond the road sign. Here the polymictic breccia of the platform margin facies is exposed. The clasts are floating in a matrix of sandy dolomite and are interbedded with cross-bedded sandstones. Clast composition includes dolomite, sandstone and dolomitic sandstones. Beds are structureless and poorly sorted. These breccias are interpreted to represent talus deposits formed at the edge of the platform. These breccias can be traced to the north, where they form a rim around the St. Albans Reentrant. Mehrtens and Borre (1987) have documented that the Monkton passes laterally into the Rugg Brook Conglomerate within the basin. Return to cars and continue east on Route 2.

STOP 5. Winooski platform margin facies
Walk from the parking lot back to, and across the intersection, to the outcrop on the southwest side. This is an exposure of recrystallized dolomite, cross-bedded, and in places oolitic, of the upper most Winooski. Cross the road to the low-lying outcrop on the east side of Route 7. Note the variable clast composition and abundance of sand in the dolomite matrix in this Winooski platform margin breccia. These outcrops of Winooski at Chimney Corners and the adjacent I-89 exit ramps are the northernmost outcrops of Winooski Dolomite in northwestern Vermont. Immediately to the north on I-89 and Route 7 are exposures of the Rugg Brook Dolomite, a breccia deposit within the St. Albans Reentrant.

Outcrops of the Monkton Quartzite occur as roadcuts all along I-89.

First outcrop of Winooski Dolomite on the median of I-89

STOP 6. Salmon Hole - tidal flat facies of the Monkton, Winooski and Danby Fms.
Descend the pathway down to the broad bedding planes of the Monkton in the south bank of the river. This beautiful outcrop of Monkton is in danger of being destroyed by dam construction. Examine the multitude of rippled surfaces, and note the multiple paleoflow directions. Examine these rippled beds in cross section and note that they are composed of rippled dolomite, silty dolomite, and fine-grained sandstone with shale drapes, a typical tidal bedding style. Examining bedding planes again, look for both vertical and horizontal burrows. Mudcracks can also be found. The thick, structureless buff-colored dolomite bed near the top of the Monkton is interpreted to be supratidal in origin (carbonate mud washed up onto the tidal flat during a storm?). This implies that the section of Monkton just examined would be the upper portion of a shallowing-up cycle, which characterize the Monkton Quartzite. From having seen the subtidal and platform margin facies of the Monkton at Stop 4 you can now compare the features seen at the two outcrops. The tidal flat facies seen here and at other localities around the Burlington and Winooski areas were prograding northward towards the platform margin in the Milton region. The Monkton/Winooski contact is under water here but can be examined at Whitcomb's Quarry at the I-89 interchange. It is gradational over about 10 meters, with progressively decreasing amounts of sand up section into the Winooski.

STOP 7. Danby Quartzite and Winooski Dolomite
You are now on the bedding planes of the shallow subtidal facies of the Danby Quartzite (Figure 5), which is a dolomitic sandstone at this exposure. There are many exposures of sedimentary structures at this outcrop, including hummocky cross stratification, complexly-woven ripple bundles, bedding planes with interference ripples, and graded beds. Biogenic structures include small LLH stromatolites and oncolites. Most of these features suggest that the sediments of the Danby were frequently reworked by storm action, re-suspending and reworking the substrate, and rapidly depositing sediment during post-storm surge ebb flow.
During low water levels the entire Danby can be walked out from its contact with the Winooski on this side (upstream) of the bridge. The contact is gradational and is characterized by increasing amounts of quartz sand in dolomite until it becomes a dolomitic sandstone. The Winooski Dolomite does not exhibit many features but thin wisps of carbonaceous material with sand grains concentrated along the laminae are interpreted to be cryptalgalaminites.

STOP 8. Rockledge Conglomerate
In the field immediately to the north of the road are scattered outcrops of the Rockledge Conglomerate limestone clast facies. Examine exposures of the conglomerate and the poor sorting and angularity of clasts, and the sandy limestone matrix. Pods of the conglomerate, interpreted as individual flows of high density turbidity currents, are surrounded by the laminated siltstones of the Skeels Corners Slate.

Rugg Brook Formation
Small ridges 100 yards to the north are composed of massive dolomitic sandstone facies of the Rugg Brook Formation

A5: GRENVILLE CALC-SILICATE, ANORTHOSITE, GABBRO, AND IRON-RICH SYENITIC ROCKS FROM THE NORTHEASTERN ADIRONDACKS
ELIZABETH B. JAFFE and HOWARD W. JAFFE
Department of Geology and Geography
University of Massachusetts, Amherst
The Marcy anorthosite massif is delineated by a major NW-SE-trending lobe and a smaller N-S-trending lobe which coalesce to the S to form a heart-shaped outcrop pattern covering 5000km2. (Fig. 1). In section, the major NW-trending lobe approximates a piano bench or slab 3-4.5 km thick with two legs or feeder pipes extending at least 10 km down according to the geophysical model of Simmons (1964), whereas Buddington (1969) favored an asymmetrical domical shape based on extensive field mapping and other considerations. The massif consists of a coarsely crystalline core of apparently undeformed felsic andesine anorthosite thrust over a multiply deformed roof facies consisting of gabbroic-noritic anorthosite, gabbroic anorthosite gneiss, and quartz-bearing ferrosyenite-ferromonzonite facies (Pitchoff Gneiss). Remnants of a siliceous carbonate- and quartzite-rich metasedimentary sequence and associated garnet-pyroxene-microperthite granulites form discontinuous screens and xenoliths in the roof facies. Xenoliths of any kind are very rare inside the felsic anorthosite of the core, but abound in the gabbroic anorthosite of the roof facies.
We will visit ten outcrops which include all of the major rock types (Fig. 1) of the massif, and that lie principally in its multiply deformed roof facies.
That regional metamorphism took place at high pressure, in the range of 8-10 kbar at about 800°, is indicated by the occurrence of orthoferrosilite, Fs95 + quartz, and the absence of any vestiges of fayalite in the ferrosyenite facies of the Pitchoff Gneiss (Jaffe et al., 1978). Because recent Sm147-Nd143 age dating yields 1288 M.Y. for the age of magmatic crystallization of the Marcy anorthosite (Ashwal and Wooden, 1983), and older Pb-U age dating by Silver (1969) yields about 1130 M.Y. for crystallization and about 1100- 1020 for metamorphism, the Grenville orogeny may have spanned as much as 200 M.Y. and it is difficult to fix the peak of metamorphism with a specific thermal or tectonic event within this time span.

A5: GRENVILLE CALC-SILICATE, ANORTHOSITE, GABBRO, AND IRON-RICH SYENITIC ROCKS FROM THE NORTHEASTERN ADIRONDACKS

STOP 1. Fayalite-Ferrohedenbergite Granite, Locality Af-1-A
Iron-rich granitic-syenitic-quartz monzonitic rocks, ascribed to a charnockitic gneiss series, are abundant in the northeastern and central Adirondacks, where they occur in close association with anorthositic and metasedimentary calc-silicate rocks in the Marcy Massif. Most of these contain iron-rich orthopyroxene (eulite or orthoferrosilite) with quartz, an assemblage stabilized at the high operable regional metamorphic pressure of about 8 kbar, with T = 700-770°C (Jaffe, Robinson, and Tracy, 1978: Bohlen and Boettcher, 1981). Other members of this alkali-feldspar-rich series contain fayalite and quartz in place of orthoferrosilite and quartz. From tables 1, 2, 3, 4, and Fig. 9 and Table 7 from Jaffe, Robinson and Tracy (1978), (Appendix I) it is reasonable to assume that both of these rock types were recrystallized under similar metamorphic conditions. Work by Bohlen and Essene (1978) and by Ollilla, Jaffe, and Jaffe (1988) indicate that these rocks had igneous precursors that crystallized above 900°.
Here, at Stop 1, we will visit outcrops of the fayalite-ferrohedenbergite granite and later, at Stop 4, we will visit a eulite-ferrohedenbergite syenite gneiss on Pitchoff Mt. in the 15' Mt. Marcy quadrangle.
A circular outcrop area, about 1 km in radius from the center of Ausable Forks village, was mapped by Kemp and Alling (1925) as an olivine-bearing quartz nordmarkite. They located several quarries within this outcrop area. On a fresh break, the rock shows the greenish cast typical of the ferrosyenites and charnockitic rocks of the northeastern and central Adirondack region. It is a medium-grained (1-5 mm) hypersolvus granite, in places gneissic, with a color index of 5-15. Similar fayalite-bearing granitic rocks were described by Buddington and Leonard (1962) from the Cranberry Lake quadrangle, near Wanakena, from the St. Lawrence Co. magnetite district of the central Adirondacks. At Wanakena, and very likely at Ausable Forks, eulite- or orthoferrosilite-ferrohedenbergite granitic-quartz- monzonitic gneiss is closely associated with the fayalite-ferrohedenbergite granitic rock. Fayalite and ferrosilite, together with quartz, have not thus far been found in the same specimen; if they were it would provide a precise geobarometric value for the pressure of regional metamorphism. From Fig. 9 and Table 7, Jaffe, Robinson and Tracy, (1978) (see Appendix I) it will be seen that the assemblage orthoferrosilite + quartz gives a minimum P, whereas fayalite + quartz gives a maximum P. A range of 7-9 kbar at 600° or 10-12 kbar at 800° outlines the extremes of the metamorphic P-T conditions. Recent work by Ollila, Jaffe and Jaffe (1988) indicates that the orthoferrosilite in Pitchoff Mt. syenite gneiss is actually an inverted pigeonite crystallized from a magma above 9 kbar and 900°c, conditions in excess of those accepted for the regional metamorphic peak.
In the Ausable Forks area, fayalite-ferrohedenbergite granite contains only trace amounts of hornblende: in outcrops where hornblende becomes abundant, fayalite is pseudomorphously altered to a brown fibrous serpentine or talc. The granitic rocks are cut by dikes of hornblende granite pegmatite and diabase.
The fayalite-ferrohedenbergite granite differs from the orthoferrosilite-ferrohedenbergite granitic-syenitic gneisses in several important aspects;
1) the fayalite granite is massive to poorly foliated, while the ferrosilite granitic gneiss is well foliated.
2) the fayalite granite is hypersolvus, carrying only a "strip" or "striped" microperthite that is slightly unmixed to sodic plagioclase and orthoclase, whereas the ferrosilite granitic gneiss is subsolvus, containing blebby and patchy microperthite more unmixed to sodic plagioclase and partly inverted to microcline, and this microcline microperthite coexists with an intermediate plagioclase,
3) the fayalite granite does not contain garnet because of the absence of intermediate plagioclase, whereas the ferrosilite granitic gneiss always carries garnet.
All of this suggests that the fayalite granite might be younger than the ferrosilite granitic gneiss. We concur with Buddington and Leonard (1962) who suggested that the fayalite granite could have originated from the fractional remelting at depth or the pyroxene granitic gneisses, with its intrusion occurring during the waning stages of deformation.

STOP 2. Anorthosite Near Covered Bridge At Jay
Outcrops just beyond a covered bridge about 0.32 km E of Ausable Forks center show the characteristic textures of anorthositic rocks along the margins of the Marcy Massif. In the roadcut, anorthositic block structure shows up to 2 m blocks of coarse, cumulate-textured andesine anorthosite, and coarse hypersthene (to 25 x 1S cm) enclosed in a gabbroic anorthosite. Dark layers, up to 2.5 cm thick, occur within the country rock. Outcrops in the East Branch of the Ausable River are principally of coarse andesine anorthosite with a megacryst index of about 20-30 and a color index of only 1. Numerous shear veinlets crisscross the anorthosite, trending N40E and N10W for the most part.

STOP 3. Grenville-Anorthosite Hybrid Gneiss 3.4 Km S Of Upper Jay On Rte 9N
We are located in a 6.4 x 1.6 km north-trending section of Grenville strata consisting largely of calc-silicate-amphibolite-marble assemblages. Graphitic marbles occur across the Ausable River to the W of this roadcut. All these have been intruded and pervaded by sills of gabbroic anorthositic composition, resulting in the formation of Grenville-anorthosite-hybrid gneisses. Subsequently these were intruded by a sill of gabbro that forms the center of the E side of the large road cut on Rte. 9N (Fig. 2).
The section may be divided into three parts:
1) a lower unit consists principally of a mottled granular black and white sphene-augite-andesine calc-silicate gneiss discontinuously interlayered with black hornblendite-amphibolite lenses presumably of volcanic origin. The granular mottled host rock consists of white andesine, An32-39, black augite, and 5-10% of red-brown to yellow-brown sphene. The black amphibolitic layers contain mostly brown hornblende along with white plagioclase now altered to prehnite and calcite.
2) a central unit is a biotite-hornblende-hypersthene-augite-garnet-plagioclase metagabbro sill. The abundance of garnet, 20%, suggests that the gabbro sill may have been olivine-rich. The sill shows sharp contacts above and below with the anorthosite-calc-silicate-hybrid gneiss.
3) above the upper contact of the gabbro sill, the rock is augite-andesine An39-40 gabbroic anorthosite gneiss intercalated with dark amphibolite and calc-silicate layers.
Sporadic large garnets up to 6 cm in diameter occur along contacts of anorthositic and mafic layers.
The outcrop on the W side of the road shows a well-developed high strain pencil lineation, oriented N25E.

STOP 4. The Pitchoff Gneiss-Ferrosyenite Facies, PO-2
The foot of Lower Cascade Lake. Park at the lakeside in the second parking area on the left, just past a sign FALLEN ROCK 1 1/2 MILE. Be very careful cutting across traffic: this is a busy high-speed highway. Recross the road on foot, again with great caution. Walk back toward the FALLEN ROCK sign, to a rough trail up the talus just short of the sign. The talus and cliff are both steep and full of loose rocks: be considerate of those below and behind.
The prominent, southeast-facing cliff we are climbing to is a ferrosyenite gneiss that crystallized from a melt prior to its metamorphism. It is one of a group of quartz-poor, alkali-feldspar- and ferroan-pyroxene-rich igneous rocks that acquired their gneissic fabric during an episode of isoclinal and recumbent folding associated with the Grenville orogeny at about 1100 M.Y. The persistent proximity and intimate intercalation of these gneisses with "Grenville" supracrustal rocks suggests that they may have initially been iron-rich felsic volcanics, or perhaps sills, interlayered with siliceous dolomites, calcareous quartzites, marls and basaltic flows comprising a Proterozoic series of rocks deposited about 1350 M.Y. This Grenville age is estimated from Ashwal's (1983) recent Sm147Nd143 date of 1288 M.Y. believed to represent the age of crystallization of the Marcy anorthosite massif-core facies. Following the model of McLelland and Isachsen (1980) for the southern Adirondacks, we suggest that, in the High Peaks Region of the northeastern Adirondacks, a "typical" Grenville supracrustal sequence correlative with rocks of the Central Metasedimentary Belt (Wynne-Edwards, 1972) was buried in a plate-tectonic event or events to a depth of about 70 km (42 mi), that of a doubly thickened crust. Following Emslie (1977), we envisage the birth of an anorthositic magma from the fractionation of copious amounts of orthopyroxene from an already-fractionated Al-rich gabbroic magma. Under these deep-seated conditions, the high pressures and temperatures plus the availability of Grenville strata- derived CO2-rich fluids initiated the formation of potassium- and iron-rich, relatively quartz-poor, melts of syenitic to monzonitic composition (Wendlandt, 1981). Ascent, intrusion, and emplacement of the syenitic melt at levels on the order of 25-35 km (15-21 mi) and temperatures of 800-900° induced deep contact metamorphism of appropriate Grenville rock types. Here, at the easternmost part of the PO-2 outcrop, designated PO-2Gv (Fig. 3), a calc-silicate sequence infolded with the ferrosyenite contains the assemblage: wollastonite-diopside-grossular-quartz. Because anorthosite is absent, the contact-metamorphic origin of the wollastonite must be attributed to the intrusion of syenitic melt. Further, because the ferrosyenite contains relict inverted pigeonite, which now consists of host orthoferrosilite, 100Fe/(Fe+Mg)=85-92, the melt must have crystallized at temperatures of 850-900° (Lindsley, 1983 and Ollila, Jaffe and Jaffe, 1988). Alternatively, shallow emplacement with crystallization of fayalite and quartz, later deeply buried and converted to orthoferrosilite and quartz, is conceivable, yet unlikely, because no relict olivine, whatsoever, has been observed by Jaffe or by Ollila in quartz-bearing syenitic rocks of the Mt. Marcy and the Santanoni quadrangles. Fayalite (Fa95) plus quartz, but with orthopyroxene absent, has been described from quartz-syenitic rocks in the Cranberry Lake quadrangle to the west (Buddington and Leonard, 1962, Jaffe et al. 1978) and in the Ausable Forks quadrangle to the northeast (Kemp and Alling, 1925 and Jaffe et.al., 1978). A deep emplacement with high pressure crystallization is consistent with field observations and experimental data for all of these rocks.
At the PO-2 outcrop, we will split into several smaller groups: the footing can be a bit tricky. Remember not to step back for a better look at the outcrops. The first or westernmost cliff consists of strongly foliated ferrosyenite gneiss, N45E,30W, with a large inclusion of shonkinite granulite (Fig. 4, Table 5). The foliation continues through the inclusion. The southwest end of the inclusion is sharply cut off by the gneiss but the northeast end fingers out. The inclusion is cut by a discordant vertical tongue of gneiss which becomes a subhorizontal pegmatite vein. At the northeast end of this cliff, the ferrosyenite gneiss is cut by an unfoliated aplite dike. Small amphibolite inclusions can be seen in the gneiss.
We will proceed cautiously about 300' (91.5 m) along the base of the cliff to the northeast, across a stream and a gully. Here we see several larger folded amphibolite inclusions in the ferrosyenite gneiss (Fig. 3). The axial planes of these folds are approximately parallel to the pervasive foliation. We will now crawl a few feet up the gully: in its cast wall are exposed marbles and calc-silicates intimately infolded in the ferrosyenite gneiss. Wollastonite occurs in these calcsilicate beds (Fig. 3). If we make allowance for the plasticity of the marble, these folds are also approximately parallel to the pervasive foliation. There is a cave in the marble a little higher up this gully. On the opposite side of Lower Cascade Lake, in the anorthosite, another cave can be found a few hundred feet higher up. Caves are common in New York State, but these two must be among the few in Precambrian rocks.

STOP 5. Grenville Marble-Syenite-Anorthosite Section South Of Keene
Drive five miles (8 km) northeast on Route 73 to the first right turn after a Gulf gasoline station and almost into Keene village center. Turn right (south) on the westernmost of two small roads that parallel both sides of the East Branch of the Ausable River. Drive about 0.75 (1.2 km) miles south on this western side of Hulls Falls Road and park judiciously along the edge of this little travelled road. Descend about 25' (7.6 m) to the bank of the river watching out to avoid standing or sitting in Rhus toxicodendron which commonly grows in Grenville marble terrain. A fine river outcrop of folded Grenville marble consists of calcite (white), diopside (green), fluopargasite (black), and minor glistening flakes of phlogopite (brown) along with less abundant graphite. Pink quartz leucosyenite and blackstreaked gray-white gabbroic anorthosite gneiss have been dragged into highly contorted syntectonic folds enhanced by the plasticity of the marble and the probable molten state of the quartz syenite and gabbroic anorthosite (Fig. 5). Occasional tongues of gabbroic anorthosite cross-cut the syenitic rocks. A major vertical fracture zone, the Keene Fault Zone runs parallel to the river in a N-S direction, and is well exposed about one-half mile (0.8 km) south in a granulated anorthosite outcrop. The Keene Fault has dragged the preexisting, gently north dipping, isoclinally folded strata into fairly steeply plunging folds at this locality. A late, brittle stage of movement on the same fault has granulated and retrograded all of the brittle rock types. Feldspar in syenite is sericitized, intermediate plagioclase in gabbroic anorthosite has been albitized and veined by calcite, grossular-diopside calc-silicate rocks have been prehnitized and chloritized, but marble merely goes along for the glide.
At the northernmost end of the outcrop, the diopsidic marble and the quartz syenite are transected by a 4' (1.2 m) wide N80W,90 trending lamprophyre dike (Fig. 5) which displays good chilled margins. It is a classic lamprophyre: a dark, dense, porphyritic dike rock in which the ferromagnesian minerals occur in two generations and in which only the dark minerals form the phenocrysts. It consists of 1-5 mm diameter phenocrysts of partially serpentinized magnesian olivine, and zoned clinopyroxene with augite cores and titanaugite rims, which display spectacular zoning, intense anomalous interference colors and dispersion, and hourglass structure. The groundmass contains a second generation of microphenocrysts of titanaugite, kaersutite, titanian biotite and abundant very thin needles of apatite in a quasi-isotropic base that has too high an index of refraction to be analcime or leucite; it has a mean index of refraction = 1.525 and is either untwinned anorthoclase or a zeolite. The dike may be classified as either a camptonite or a monchiquite, but exactly conforms to neither.

STOP 6. The 1063 Mylonite
On the west side of Route 73, 1.3 miles (2.1 km) south of the village of Keene Valley at BM 1063 and opposite the Beer Bridge across the Ausable River, the anorthosite is cut by a well-developed mylonitic zone about 2' (0.6 m) wide which trends N55E,35NW. Park on the west shoulder of the road south of the outcrop and walk back. The anorthosite here appears to be the normal gabbroic type; however, the mafic minerals occur in clots and aggregates of augite+apatite, many of which are bent into mini- and microfolds. These clots and the sparse megacrysts of labradorite form a foliation which trends N70W,70SW. The coarse grained contaminated felsic anorthosite and the mafic clots of partially assimilated augite+apatite represent either remnants of a Grenville phosphate-rich calc-silicate rock, or a mafic cumulate segregated from a gabbroic anorthosite melt. The iron content of the augite, 100Fe/(Fe+Mg) = 47, while too high for felsic anorthosite, is representative for anorthositic gabbro. Further, the profusion of "100" and "001" metamorphic pigeonite exsolution lamellae in the host augite (Jaffe et al., 1975) suggest that the clots may derive from anorthositic gabbro, where such are common, rather than from a Grenville calc-silicate lithology, where they are rare. Labradorite megacrysts in this rock are nevertheless higher in anorthite than felsic anorthosites of the Marcy region, and show An50.5_54 5 rather than the typical An46-48, suggesting a probable assimilation of calcium from the augite-apatite-rich clots of xenoliths. For this reason we classify such rocks as a percalcic subfacies of the gabbroic anorthosite facies. Just north of a small waterfall, the outcrop changes dramatically: the rough foliation gives way to fine layering along which the dark minerals occur as streaks and schlieren, though occasional megacrysts have escaped granulation and appear as flaser. The mylonite is focused in a 2' (0.6 m) zone which dies out gradually to the north after about 20' (6 m) giving way again to percalcic anorthosite. Just beyond a covered interval, the north end of the outcrop contains a mafic rock, in rudely vertical attitude, but somewhat bent about a sub-horizontal axis, perhaps earlier than the mylonitization. It has been named "aproxite" by one of the authors, in allusion to its bimineralic apatite + pyroxene composition, which is identical with that comprising the mafic clots in anorthosite host rock at the south end of the outcrop. The mineralogy thus suggests that the "aproxite" is a folded layer in anorthosite rather than a mafic dike.
The mylonitic zone does not retain any of its primary magmatic or high grade metamorphic mineralogy but is totally retrograded to a fine-grained mixture of albite, prehnite, sericite, quartz, chlorite, pumpellyite, epidote, and calcite. Labradorite is altered by the following probable retrograde reaction:
4 Lab + Or + Water
= 2[NaAlSi3O8] + Ca2Al[AlSi3O10](OH)2+ KAl2[AlSi3O10](OH)2 +SiO2
2 Ab + Prehnite + Sericite + Qz
Augites have been drawn out into elongate lenses, spindles, and schlieren, and totally retrograded to a mixture of fibrous, isotropic chlorite and pumpellyite with a little calcite. Apatite, alone, remains unaltered, appearing as microflaser in the mylonitized base (Fig. 6).
This wet assemblage is inconsistent with deep, ductile shear and suggests that the mylonitized zone originated by brittle shear or cataclasis in a wet, relatively shallow crustal setting.
That the shear zone was initially a deep, ductile mylonite, later retrograded, remains a possibility.

STOP 7. Chapel Pond Anorthosite
Outcrops on the E side of Rte. 73 consist of andesine anorthosite containing shear zones of scapolite gneiss and a garnetiferous aplite dike (Fig. 7). For a detailed description of these outcrops, see Kelly (1974). Most of the rock here is Marcy facies andesine anorthosite.
It consists of 30-40% dark blue-gray megacrysts of calcic andesine, An45-49, set in a matrix of white andesine, hypersthene, augite, and a little hornblende. Plagioclase makes up about 90% of the rock. A fine-grained aplite dike, up to l m thick, trends roughly parallel to the road where it may be seen to crosscut the foliation marked by aligned megacrysts of plagioclase in the anorthosite. The aplite contains about 60% microperthite, 25% quartz, 10% altered plagioclase, 3% magnetite, and 1% each of garnet and altered ferromagnesian silicates.
Along anorthosite-dike contacts, fracture zones in the anorthosite contain clear andesine, An44-47, abundant scapolite, Me36-47, dark olive hornblende, and a little hypersthene. Fluids carrying Cl and CO2 apparently migrated into fractures in the anorthosite to convert plagioclase into scapolite.
The abundance of the plagioclase megacrysts here and the overall texture of the rock is typical of the anorthosite that forms the core of the Adirondack high peaks to the west.

STOP 8. Gabbroic Anorthosite Protomylonitic Gneiss
The prominent outcrop on the W side of Rte. 9 is a gabbroic anorthosite protomylonite or straight gneiss located in one of the prominent northeast-trending fault zones that abound in the NE Adirondacks. Note that the size reduction and mylonitization of this gabbroic anorthosite are not so intense as that seen at Stop 6, the 1063 mylonite.
The rock consists of very fine crenulations and streaks of hornblende, garnet, ilmenite, and augite in a fine matrix of white andesine, An32, and anorthoclase. Recrystallization took place under dry conditions, and all minerals are fresh.
The high strain nature of the gabbroic anorthosite gneiss is evident, and is illustrated by the total granulation and virtual absence of plagioclase megacrysts. An occasional block or xenolith of felsic anorthosite is present. Punky grey veins of finely altered rock occur in fracture zones.

STOP 9. Multiply Deformed Layered Gabbroic Anorthosite Gneiss
The prominent cliff on the W side of Rte. 9 is a hydrothermally altered layered gabbroic anorthosite or leucogabbro located in one of the prominent northeast trending fault zones that abound in the NE Adirondacks.
The rock contains kaolinitized andesine, titanian brown hornblende, augite, and garnet, with a little ilmenite and apatite. Compositional layering is marked, with more mafic layers rich in augite and garnet, and more felsic layers richer in altered andesine and hornblende and without garnet. Many thin veinlets of white prehnite, calcite, and chlorite crosscut the gneiss. The layered gneiss was subsequently intruded by one or more aplite dikes, composed of altered albitic plagioclase, potassium feldspar, and quartz, along with garnet, and small amounts or apatite. Garnet is altered to chlorite. The rock is sliced on a mm scale, and slickensided, fracture surfaces often being coated with bright green pistacite.
The gneiss was recumbently folded under a high strain rate and then subjected to open folding (Fig. 8). Do the conspicuous open folds delineated by the pink aplite represent:
1) refolding of the recumbently folded gneiss?
2) a sheath fold squeezed or squirted up inside the gneiss? .
3) are there one or two aplite dikes, and does the aplite layer close into a fold hinge beneath the road?
Just across Rte. 9 on the E side, the rock has a completely different texture. About half the rock consists of 0.5-5 cm green, euhedral kaolinite pseudormorphs after plagioclase phenocrysts lying in a foliated matrix of brown hornblende, quartz, anorthoclase, augite, magnetite, and apatite. The fine black matrix is unaltered, in contrast to the large plagioclase phenocrysts. The green kaolinite pseudomorphs show good albite and Carlsbad twinning, but under the microscope only trace amounts of unaltered plagioclase remain. Compositionally, the rock is a quartz gabbro or quartz diorite. However, it may represent a porphyritic gabbro with its groundmass recrystallized to a metamorphic assemblage.

STOP 10. The Woolen Mill Gabbro And Anorthosite, Rte. 9N
On Rte. 9N about 1.6 km W of the intersection of Rtes. 9 and 9N at the golf course on the southern edge of Elizabethtown are outcrops of gabbro and anorthosite at the site of an old, long disused broken dam. Recent reconstruction of the dam and installation of a penstock along the Branch River just N of the road may limit our examination of a fine exposure of anorthosite block structure along the river.
On the S side of the road, a prominent cliff exposes the very irregular contact of a garnet- and magnetite-rich gabbro with a white gabbroic anorthosite in which almost all of the plagioclase megacrysts have been granulated. A rude foliation may be observed in both rocks. Modes of the gabbro and optically determined compositions of plagioclase, augite and hypersthene from the gabbro and anorthosite are given in Table 6. The contrast in Fs content of coexisting clino- and orthopyroxene in gabbro and anorthosite is marked. Note that the iron-rich gabbro has abundant garnet, while the relatively iron-poor anorthosite has none. The presence in the gabbro of isolated blue-gray, well-twinned (Carlsbad and albite) labradorite xenocrysts and occasional xenoliths, as well as contact relations, suggests that the gabbro has intruded the anorthosite before regional deformation. Toward the center of the roadcut, a pink aplite dike has intruded both the anorthosite and the gabbro.
The complexity of the contact relations here has led different geologists to different interpretations. Kemp and Ruedemann (1910) and Kemp (1921) reported that river outcrops showed "anorthosite tonguing in to the dark supposed gabbro" and suggested that the gabbros might represent "surviving inclusions of Grenville sedimentary gneisses impregnated with matter from the anorthosites." They suggested that the Woolen Mill gabbro was thus an old Grenville rock hybridized by later intrusion of anorthosite. Commenting on this interpretation, Miller (1919) assigned these plagioclase-megacryst-bearing gabbros to the Keene gneiss, which he believed to be a syenitic magma containing assimilated anorthosite! Buddington (1962) described the Woolen Mill gabbro as a typical olivine gabbro intrusive into anorthosite, in which olivine was extensively converted to garnet during regional metamorphic recrystallization. No evidence of relict olivine could be found under the microscope.
How would you interpret the outcrop relations?

A6: METASEDIMENTARY AND METAVOLCANIC ROCKS OF THE AUSABLE SYNCLINE, NORTHEASTERN ADIRONDACKS
Philip R. Whitney
Geological Survey, New York State Museum
James F. Olmsted
Center for Earth and Environmental Sciences
State University of New York College at Plattsburgh
On this trip we will examine two sections of granulite facies metamorphic rocks, exposed in stream cuts in the southern and central Ausable Forks 15' quadrangle. The first section is dominated by calc-silicate rocks, marbles, and quartzites, typical of metasedimentary rocks in the northeastern Adirondacks. The second includes both metasedimentary rocks and the Lyon Mountain Gneiss, an unusual lithologic unit comprising a diverse suite of rocks which we believe are chiefly metavolcanic. Points for discussion on the trip include possible protoliths, the tectonic and sedimentary environment at the time of deposition, the metamorphic environment(s), and contact relationships with olivine metagabbros and anorthositic gneisses. Both stops on this trip involve moderately long hikes along scenic Adirondack brooks. While the hikes are not particularly arduous, we recommend sturdy boots and the exercise of caution; some of the stream banks are quite steep, and frequent crossings of streams on slippery rocks will be necessary.

A6: METASEDIMENTARY AND METAVOLCANIC ROCKS OF THE AUSABLE SYNCLINE, NORTHEASTERN ADIRONDACKS

Clintonville.
This hamlet is a former iron mining town said to have had a population of over 10,000.

Unusual ferrohedenbergite-fayalite granite
Outcrops in roadcut on right are an unusual ferrohedenbergite-fayalite granite, first described by Buddington (1939). This may be a reduced facies of the Lyon Mountain Gneiss, or a subsequent intrusive rock.

Differing mechanical properties of various rock types "The Snake"
Stop at several small outcrops in a bank on the L (east) side of the road, directly downslope from a house. Cameras are a must at this stop, but no hammers, please. This informal stop illustrates the differing mechanical properties of various rock types, including marble, diopsidite, amphibolite, and granitic gneiss. This exposure has been called "The Snake", for obvious reasons.

Metanorthosite of the Jay Dome
Exposures on R in the bed of the Ausable River are metanorthosite of the Jay Dome, cut by several unmetamorphosed mafic dikes.

STOP 1. Gelina Basin.
The road forks at this point, with the R fork leading steeply uphill. There may be a gate across the L fork. This is private property, owned by Ward Lumber Co. in Jay. If you come here on your own, get permission. We will park here and proceed on foot up the R fork. If you have an altimeter, set it for 1280 feet. After about a half mile, the road ends at a hunting cabin in a clearing. Walk to the R of the cabin past the john, where you will find a trail that follows the top of a steep bank. Follow the trail S to about 1800 feet altitude, and work your way dawn the bank to the stream at the bottom. This unnamed, north-flowing stream drains a cirque (Gelina Basin on the 15' quadrangle map) on the north flank of Jay Mountain. We will attempt to hit the stream at about 1700 feet and traverse upstream over a well exposed section of NNE-striking metasedimentary rocks.
1730-1750' (altitudes approximate) Calcsilicate rocks with diopside and wollastonite, locally rusty weathered, with quartzite layers.
1750-1760' Strongly foliated amphibolite, overlain by coarse, rusty calcite-diopside-phlogopite-graphite marble.
1780-1820' First of three waterfalls. At the base of this falls, layered diopside-wollastonite calcsilicates (WoDi) and quartzite are exposed. The caprock is tremolite-bearing quartzite; just above this is Mg-rich enstatite-diopside-tremolite-quartz rock.
1830' 5' cascade over diopsidite and diopsidic marble with thin quartzite layers.
1840- 1870' Interlayered metasedimentary rocks (diopsidites and WoDi) and thin amphibolites.
1880-1900' Amphibolite, overlain by metasedimentary rocks, including a calcite-diopside-wollastonite-grossular-idocrase marble at the base of a second waterfall. The cap of this falls is a dark, feldspathic diopsidite with locally abundant sphene. The amphibolite here may be a sill or dike of olivine metagabbro satellitic to the larger body exposed just upstream.
1910-1960' Third falls. The lower part of the falls is a cascade over banded WoDi rock; the upper part is olivine metagabbro locally mixed with granitic gneiss. The gabbro contact here appears to have a steep easterly dip, truncating the more gently dipping metasedimentary layers. Thin sections of the WoDi rock here show thin rims of grossularitic garnet around wollastonite, possibly a result of the reaction wollastonite + plagioclase = grossular + quartz.

STOP 2. Clear Pond Park and Doyle Brook Gorge.
Park on R side of road. To reach the traverse up Doyle Brook we will walk along a private logging road (permission needed) that runs SW from Trout Pond Road. [Note: the 1953 USGS topographic map (1:62,500) is accurate in this area; the 1980 1:25,000 version is not]. Proceeding SW along the logging road, we will pass Copper Pond, which occupies a small basin in albite gneisses of the LAG and MAG facies. Just S of Nesbitt Pond, a short trail leads S to Doyle Brook. From here, we will traverse upstream. The stream gradient is small, so altitudes are not listed. The first rocks encountered in the streambed are amphibolites. A short distance upstream, Doyle Brook emerges from a slot formed at an ENE-trending fault here occupied by an unmetamorphosed mafic dike of indeterminate age that shows evidence of multiple episodes of intrusion. The walls of the gorge are MAG facies albite gneisses, with massive, banded, and megacrystic variants all present. Notice the complex folding in the banded gneisses.
After leaving this first slot, continue upstream along a flat stretch with occasional outcrops of the GG and LAG facies, same quite magnetite-rich. Then enter a second gorge, walled by heterogeneous, intensely fractured LMG, mostly of the GG facies. Shortly beyond the SW end of this gorge, the stream crosses a concealed contact between the LM3 and the under lying metasedimentary rocks. The first outcrop of the latter is a rusty-weathered, graphitic, sillimanite-garnet metapelite. Continuing upstream, the course of the stream swings around to a nearly NS direction, with outcrops of garnetiferous granitic gneiss. At the S (upstream) end of this segment are several marble outcrops, including a coarse white calcite marble with serpentine and graphite, and a nearly pure, gray, tan-weathering dolomite marble. A large spring marks the underground outlet of Lawson Pond, located just to the south and about 80' higher in elevation. The surface outlet shown on the map does not exist. The rocks here strike NNE and dip east; the marble overlies the granitic gneiss seen in the previous outcrop. Another bend in the stream leads first SW and then W (downsection) over outcrops of amphibolite and rusty calcsilicate rocks, back into garnetiferous granitic gneiss, followed by gabbroic anorthosite gneiss. The latter is part of a large, irregular lens of metanorthosite within the layered metamorphic rocks. At this point we will leave the stream and walk back to the access road, following the N rim of Doyle Brook gorge.

A7: IRON INDUSTRY OF THE EASTERN ADIRONDACK REGION
JAMES C. DAWSON
Center for Earth and Environmental Science
Plattsburgh, NY 12901
JOHN R. MORAVEK
Plattsburgh , NY 12901
MORRIS F. GLENN
Mapping and Charting Department
Defense Mapping Agency
u.s. Department of Defense
Washington , DC 20310
GORDON C. POLLARD
Department of Anthropology
Developments in mining and iron smelting in the Adirondack-Champlain region commenced with effective American settlement after the 1812-1814 war, and in some instances preceded it. Iron ore had been observed on the lakeshore near Crown Point as early as 1749 by Swedish naturalist Peter Kalm (1770).
The crude ironworks on the manor of British military officer, Philip Skene, at Skenesborough (Whitehall, NY) at the head of Lake Champlain smelted ore from the vicinity of what later became the Cheever Mine a few miles north of Port Henry, NY (Morton, 1959). At the mouth of the Saranac River on Lake Champlain, Zephaniah Platt and associates operated a Catalan forge or bloomery in 1798 using ore from Vermont. In 1801, an ironworks was erected at Willsboro Falls on the Bouquet River.

A7: IRON INDUSTRY OF THE EASTERN ADIRONDACK REGION

STOP 1. Lyon Mountain Mines
Lyon Mountain was the site of the Chateaugay ore beds. During its century-long life as a mining center, it produced more ore in aggregate than any other area in the Adirondack-Champlain Region , except for the Mineville-Witherbee complex of Essex County. The Prall Vein or Mine 81, an open pit situated two and a half miles to the southwest, was the probable source of ore that supplied a bloomery operating on the Chateaugay River to the north as early as 1803, but the Chateaugay deposits at Lyon Mountain were not discovered until 1822-1823. Development lagged for a full half century due to the remoteness of the area.
In 1868, a group of four Saranac Valley speculators purchased the ore beds and devised plans for an extensive enterprise. In 1873, this interest was transferred to the newly organized Chateaugay Iron Ore Company. Substantial quantities of ore were shipped to the large bloomery erected in 1872 at Popeville. The Chateaugay Railroad Company was formed to construct a railroad from Lyon Mountain east to the rail terminus from Plattsburgh at Clinton Prison in Dannemora. This was completed in 1879. The railroad, mining, and smelting interests were consolidated into a powerful new firm, the Chateaugay Ore and Iron Co. in 1881. This creation launched development on a great scale.
Our excursion will walk by the head frames of the later works and a former employee of Republic Steel who is familiar with the structures will describe their purpose at the time that operations were closed in 1967.
In Lyon Mountain, New York century-old residential structures border the mines, together with the 1920s-vintage standard "company" houses that line Route 374 (Belmont Street). Today's inhabitants, descendants primarily of Lithuanian, Polish, Russian, Italian, Spanish, Irish, and French-Canadian immigrants who labored in the mines and mills, are either retired or, if employed, commute to jobs on the outside, or since 1984, have found jobs on Belmont Street itself at the former public school house, now converted to a minimum-security state prison.

STOP 2. Site Of Catalan Forge At Standish
The Chateaugay Ore and Iron Company had an 8-fire bloomery at Standish by 1883. This was enlarged several times until it was shut down in 1907. In 1885 the company constructed a blast furnace at Standish to produce pig iron in addition to bloom iron (Linney, 1934). The trade name "Chateaugay" quickly gained a highly favorable reputation for excellence. Blooms, pigs, and the celebrated low-phosphorus magnetite were widely sought after, and commanded premium prices everywhere. The crude ore was/is rather lean, averaging only 26%-28% iron content, but was practically free from phosphorus, sulfur, and other chemical impurities, and could be readily beneficiated to 65-70% iron content. Iron and high-grade alloy steels made from Chateaugay ore were renowned for toughness and strength and widely used for the fabrication of wire rope, munitions, ordnance, and other specialties. For such purposes, it was considered unsurpassed in all the world, and steel cables made of Lyon Mountain's ore can be found today in such mighty and notable structures as the Brooklyn bridge, the Golden Gate Bridge in San Francisco, and the George Washington Bridge in New York City.

STOP 3. Caldwell Mine Site
Ore was discovered at the Caldwell site in 1840 and mining began in 1841. This was the first iron ore discovery in the Saranac River valley and it resulted in the establishment of a settlement named after the original property owner Leander Cadwell. Early newspapers and subsequent histories managed to misspell his name .
Leander Cadwell and Lawrence Myers erected four forges and a separator at the site in 1844. By 1846 this was expanded to six forges, two separators, two trip hammers and a finishing hammer. About 100 men were employed. Myers became the sole owner in 1855 and by 1860 the mine was yielding 1500 tons of iron ore per year. The property changed ownership in 1863 and again in 1873 and the mine was considered "mined out" and closed in 1881.
Historical archaeological research has been conducted by Gordon C. Pollard (Pollard, 1985). The research has produced a map of the eleven-acre site and has documented the mine, ore processing site, charcoal production and storage, residences and company store. Dr. Pollard will be on hand to guide this portion of the field trip.

STOP 4. Palmer Hill Mine Site
Iron ore was discovered at Palmer Hill, in the Town of Black Brook, in 1824-1825 by Zephaniah Palmer. In 1829 he sold a three-eights interest, the eastern extension of ore, to the Peru Steel and Iron Company. Later he sold the western five-eights interest to the J. and J. Rogers Iron Company of Au Sable Forks, NY.
Mining commenced about 1830 and continued to 1892-1893. The Palmer Hill Mines were initially excavated as open pits but as time passed increasing depth rendered impractical the removal of overburden, and drifts were developed as the companies followed bands of ore ranging in thickness from 10 feet to 20 feet. The deepest set of workings bottomed at a depth of 2,200 feet, down a dip slope that began at 60° and flattened to a nearly horizontal position at the bottom. Other pits extended to a depth of 1,000 to 1,200 feet down dips of roughly 30°. In some cases workings followed shoots of ore across the dip. The texture of Palmer Hill ore was rather fine, and in appearance and mode of occurrence resembled the Chateaugay ores at Lyon Mountain.
Our stop will briefly explore the honeycombed southern brow of Palmer Hill, with its numerous irregular openings and chambers and piles of rock and mine rubble. This site continues to hold a certain fascination, and remains potentially dangerous, to local explorers and students. In places the surface workings have caved in and are inaccessible, but numerous pits do allow access and invite cautious investigation. Deep water fills the lower parts of these "caves," and in some pits ice can be found at any time of the year.

STOP 5. Driving Tour Of Clintonville.
The Peru Steel and Iron Company was heavily engaged in smelting and iron fabrication in Clintonville, New York and reached its peak prosperity in the 1850s and 1860s when 900 men were employed (Moravek, 1976). The bloomeries, separator and rolling mill occupied more than a mile of the north bank of the Ausable River.
The national decline of the iron industry in 1873 was hard on Clintonville and by 1880 the activities of the Peru Steel and Iron Company at Palmer Hill and at Clintonville were over.

STOP 6. Fletcherville Blast Furnace And Sherman Mine.
Friend P. Fletcher joined with Silas H. Witherbee and Jonathon G. Witherbee to manufacture iron in a furnace on Fletcher's 4000 acres of land. Jerome B. Bailey of Plattsburgh, New. York built the blast furnace in 1864-1865. It was a stone stack 42 feet high, later increased to 61 feet, on a 42 foot square base. Nearby ten enclosed rectangular brick charcoal kilns were constructed, each capable of charring 65 cords at a time (Allen, 1975). The town that sprang up was known locally as Fletcherville, but people in Westport referred to it as Seventy Five because it was thought to be in Lot 75 in the Town of Elizabethtown. A survey showed that it was really in Lot 48 of Westport which then received the taxes.
In the early 1870s much of Fletcher's pig iron was shipped from Port Henry to Troy, New York where it was used in the experimental Bessemer steel process for railroad track (Witherbee, 1874). The early success began to fade in the 1870s and after Fletcher's death in 1874 the works closed down.
The Sherman Mine and other small mines on the Fletcher property were occasionally revisited with activity at the Sherman continuing as late as 1921.
Our visit will examine the remains of the blast furnace, charcoal beds, ore roasting kilns, various out buildings and perhaps the Sherman Mine.

STOP 7. Driving Tour Of Witherbee
The mines of the Mineville-Witherbee-Fisher Hill area in the Town of Moriah have been the most productive iron ore producers in the eastern Adirondacks. Our drive will circle through the sites of the "Old Bed," "21," "Barton Hill," "Harmony," and "Joker" mines of the extensive Mineville Group (Kemp, 1908). These mines were greatly expanded in the 1860s by the Port Henry Iron Ore Company after their initial discovery about 1825 (Warner and Hall, 1931). A variety of interests including the Witherbee, Sherman and Company operated in the area until Republic Steel Corporation took control from 1937 to 1971. Be sure to note the concrete block buildings that incorporate tailings material (Lincoln, 1909).

B1a: LATE WISCONSINAN LACUSTRINE AND MARINE ENVIRONMENTS IN THE CHAMPLAIN LOWLAND, NEW YORK AND VERMONT
David A. Franzi
Center for Earth and Environmental Science
Plattsburgh, New York 12901
Thomas M. Cronin
United States Geological Survey
M.S. 970 National Center
The Champlain Sea was a Late Wisconsinan marine incursion into the isostatically depressed St. Lawrence and Champlain Lowlands following ice recession from the eastern St. Lawrence Lowland (ca. 12.5 to 10.0 ka (kilo anno)). The marine episode followed a freshwater proglacial lacustrine interval in the Champlain and western St. Lawrence Lowlands (Fulton and others, 1987; Chapman, 1937). Sedimentary sequences containing till, ice-contact gravel, subaqueous outwash, and sparsely fossiliferous lacustrine sediment overlain by fossiliferous marine sediment record the transition from glacial to lacustrine to marine conditions in the basin.
This trip will examine the nature of the transition from freshwater to marine conditions and the paleoenvironments of the Champlain Sea as shown by the lithostratigraphic and biostratigraphic records in the Champlain Lowland. Faunal assemblages are used to reconstruct the areal and temporal distribution of water temperature and salinity within the basin. Emphasis is placed on the microfauna, particularly the ostracodes, and how changing microfaunal assemblages record environmental changes in this part of the Champlain Sea. The data summarized here are taken primarily from detailed faunal studies of foraminifers (Cronin, 1979) and ostracodes (Cronin, 1981) which concentrated in the southern arm of the sea in the Champlain Lowland of northwestern Vermont, northeastern New York, and southern Quebec. It should be stressed, however, that the sequence of faunas found in this region are not necessarily the same as those in other parts of the Champlain Sea where different hydrologic conditions caused a distinctly different sequence of paleoenvironments (Rodrigues and Richard, 1986; Rodrigues, 1987).

B1a: LATE WISCONSINAN LACUSTRINE AND MARINE ENVIRONMENTS IN THE CHAMPLAIN LOWLAND, NEW YORK AND VERMONT

Outcrop of the Cumberland Head argillite.

Outcrop of the Chazy Gp.

Korean Veterans Memorial Bridge (formerly Rouses Point Bridge).
The ruins of Fort Blunder (Ft. Montgomery), an American fort that was originally built on Canadian soil, can be seen on your left. The "blunder" was corrected by moving the border northward.

Outcrop of Stony Point argillite.

STOP 1. Town Gravel Pit, Isle LaMotte, Vermont
The predominant lithofacies consists of thinly bedded, molluscan-rich sand with minor gravelly sand and sandy to silty mud interbeds. The sands are generally medium to coarse grained and are cross bedded or horizontally laminated. Individual beds range from a few centimeters to about 20 cm thick and can be traced laterally for several meters. The sandy facies contains two biofacies, a Macoma balthica facies and a Mytilus edulus facies. The faunal assemblages were previously described by Cronin (1977 (loc. 11), 1979, 1981 (loc. 33)). Articulated valves of both species are commonly found in living position. Occurrences of Mytilus in living position in Champlain Sea deposits are rare since this mollusc usually lives attached to the substrate by a byssus and its two valves have an adont hinge that disarticulates easily.
Ostracodes and benthic foraminiferas are rare in these sands. The following species occur; Cyprideis sp.
Cythere lutea (Mueller, 1785)
Cytheromorpha macchesneyi (Brady and Crosskey, 1871)
Cytheropteron latissimum (Brady, Crosskey, and Robertson, 1874)
Cytherura gibba (Mueller, 1875)
Eucythere declivis (Norman, 1865)
Finmarchinella logani (Brady and Crosskcy, 1871)
Heterocypridcis sorbyana (Jones, 1857)
Hyocypris gibba (Rahmdohr, 1808)
Leptocythere quebecensis (Cronin, 1981)
Palmenella limicola (Norman, 1865)
Sarsicytheridea bradii (Norman, 1865)
Sarsicytheridea macrolaminata (Elofson, 1939)
Sarsicvtheridea punctillata (Brady, 1865)
Semicytherura cf. similis (Sars, 1865)
These deposits probably represent the latest phase of the Champlain Sea in this region known as the Mya arenaria Phase (Elson, 1969; Cronin, 1977). Mya arenaria is absent at this locality because it is usually found in clay substrates in low-lying areas west of Lake Champlain. Based on modern temperature tolerances of the ostracode species, the annual temperature range is estimated to have been about 0° to 20°C. Salinities during the Mya Phase were oligohaline to mesohaline (1 to 18 ppt) and all the ostracode species occurring at the Isle LaMotte locality tolerate, and often thrive in brackish water environments.
A coarse gravel facies that contains decimeter-scale foreset beds that range from poorly sorted coarse pebbly sand to open-work cobble gravel was recently exposed in a small excavation at the south end of the pit. The facies contains marine fossils that are commonly disarticulated and fragmented. The gravel facies underlies the fossiliferous sand facies described above and may be related to coarse gravel in an excavation 0.5 km to the west. Gravel foresets at both localities indicate a southward to southeastward paleocurrent. It is difficult to reconstruct the sedimentary environment that existed at the time the gravel facies was deposited because of the limited extent of the exposure at this locality. The gravel facies may be related to a high-energy littoral marine environment during the late regressive phase of the Champlain Sea. Alternatively, it may represent ice-proximal subaqueous outwash that was deposited during ice recession or possibly an ice readvance. A readvance of this nature had been previously proposed by Wagner (1972) based upon stratigraphic evidence from northwestern Vermont.

Gravel pit.
Coarse gravel foresets indicating a southerly paleocurrent are exposed in the working face of the pit.

St. Anne's Shrine.

STOP 2. Beach Ridges of the Champlain Sea.
The ridges consist of coarse, flaggy gravel that is derived from the underlying Potsdam Sandstone. Outcrops of sandstone can be observed in drainage ditches nearby and presumably bedrock underlies the ridges at a shallow depth. These ridges were mapped and described by Denny (1970, 1974) who traced them over a distance of 0.3 km. They trend roughly north-south but curve westward at their northern ends along the margin of a former headland. The elevations of the ridge crests lie between 91 and 98 m.

W.H. Miner Agricultural Institute.
The Miner Institute is affiliated with the Center for Earth and Environmental Science at P.S.U.C.

The road follows the crest of the Ingraham Esker.
Note that in places gravel operations have removed nearly all the esker material except for that under the road.

Lake Alice, named for Alice Miner.

Proceed southward along the crest of the esker.

The road follows the crest of the esker.

STOP 3. Ingraham Esker.
The sedimentology and stratigraphy of the Ingraham Esker was summarized by Denny (1972, 1974) and more recently by Diemer (in press). The esker consists predominantly of upwardly fining subaqueous outwash that was deposited in a series of esker fans at the terminus of the northward retreating ice front. The ridge is overlain by fresh water rhythmites which are in turn conformably overlain by a massive mud facies. Diemer (in press) attributes the massive mud facies to an early, transitional phase between fresh (Lake Fort Ann) and marine conditions (Champlain Sea). The section is unconformably overlain by coarse, fossiliferous gravel that probably represents wave-reworking of the previously deposited sediment during the marine regression. Denny (1972, 1974) attributed the low relief of the ridge to extensive wave erosion, however, Diemer (in press) suggests that the morphology of the ridge is a consequence of its origin as subaqueous outwash.
The faunal assemblages at this locality were described by Cronin (1977, loc. 18; 1979, 1981, loc. 4). Hazel studied ostracodes from several localities in the esker and found a total of nine species (in Denny, 1972). The esker's faunas represent the Hiatella artica Phase of the Champlain Sea (Elson, 1969; Cronin, 1977) which occurred between 11.6 to 10.6 ka The following ostracodes were found at this locality in the shelly marine gravels that cap the rhythmite facies.
Candona sp.
Cythere lutea (Mueller, 1785)
Cytheromorpha macchesneyi (Brady and Crosskey, 1871)
Cytheropteron champlainum (Cronin, 1981)
Cytheropteron latissimum (Norman, 1865)
Finmarchinella logani (Brady and Crosskey, 1871)
Heterocyprideis sorbyana (Jones, 1857)
Sarsicytheridea bradii (Norman, 1865)
Sarsicytheridea punctillata (Brady, 1865)
The annual range of bottom-water paleotemperature was probably 0° to 12°C and salinities were polyhaline, between 18 and 30 ppt, as indicated by the faunal assemblages. This salinity was the closest to normal marine conditions that was reached in this part of the Champlain Sea, at least for shallow-water environments.

Esker crosses the highway.

Point Au Roche State Park (beach and picnic area). Lunch.

STOP 4. Korths Farm Section.
This stop will involve two sections along the east bank of Ray Brook. Cronin (1977, loc. 34; 1979, 1981, loc. 84) described the faunal assemblages from the northern section approximately 100 m upstream from the Korths Farm road. Marine clays (formerly known as the Leda clay) overlie rhythmites and contain the mollusc Portlandia arctica and the following ostracodes;
Cytheromorpha macchesneyi (Brady and Crosskey, 1871)
Cytheropteron latissimum (Brady, Crosskey, and Robertson, 1874)
Heterocyprideis sorbyana (Jones, 1857)
Sarsicytheridea bradii (Norman, 1865)
Sarsicytheridea macrolaminata (Elofson, 1939)
Sarsicytheridea punctillata (Brady, 1865)
The faunas at this locality represent the Transitional Phase of the Champlain Sea (Cronin, 1977), which has been dated between 11.6 and 12.0 ka, however, the age for the earliest marine inundation in the region is not yet certain. The bottom-water temperatures ranged annually from about -2° to 10°C. Normal marine and polyhaline ostracodes are absent from the Transitional Phase and salinities fluctuated between 0 and 18 ppt. The term "Transitional Phase" was given to this interval because the faunas indicate a lacustrine to marine transition during which there was mixing of pre-Champlain Sea freshwater with the earliest influx of marine water that entered the region via the St. Lawrence estuary.
The southern section, 50 m downstream from the Korths Farm road, resulted from recent cutbank erosion. Approximately 3 m of flow-slide colluvium, derived primarily from the marine clay unit described above, overlie intact marine clay. The base of the colluvium is marked by an erosional unconformity that includes buried logs. The freshwater rhythmites were not observed at this section but may occur on or below the stream bed. Geomorphological evidence for other flow-slides exists throughout this part of the Ray Brook valley.

Roadbed is composed of wollastonite tailings from nearby mines in Willsboro.

STOP 5. Slump-earthflow.
The Whallonsburg slump-earthflow (Fig. 4) occurred during the night of 28 July, 1987, following localized, light to moderate thunderstorm activity. The slump involved the eastward displacement of 0.9 ha of Pleistocene lacustrine sediment on a cutbank of the Bouquet River. This portion of the Bouquet Valley has a history of landslide activity (Newland, 1938; Whitcomb, 1938; Buddington and Whitcomb, 1941). The 1987 Whallonsburg slump was described by Franzi, Bogucki, and Allen (1988).
The slump is roughly rectangular in plan with an average length of 85 m and an average width of 110 m. The crown is 16 m above stream level. A 0.2 ha toe bulge, composed of highly plastic clay and alluvial sediment, was raised to a height of 4.5 m in the stream channel. The slump consists of a primary mass that was involved in the initial slump and two smaller retrogressive slumps (Fig. 4).
The slump exposed 0.5 to 1 m of coarse sand and gravel over 4 m of nonfossiliferous lacustrine clay and silt at the headscarp. The lacustrine section is estimated to be 23 m thick based upon seismic refraction data from the crown. The clays are characterized by high plasticity and natural water content with low bulk density and shear strength (Fig. 5). The lacustrine unit grades upward from soft, blue-gray, thinly laminated, clay and clayey silt rhythmites to stiff , brown, thinly bedded silt and clay. The textural variation probably reflects the effects of shoaling or infilling during the waning stages of the lake's history. The overlying gravel is part of a large terrace that may be graded to Late Pleistocene marine deltas near Willsboro.
Hill slope reconstructions based on slide-deposit morphometry and laboratory analysis of the long-term shear strength of undisturbed clay samples were used to determine the geological controls on slope stability (Franzi, Bogucki, and Allen, 1988). The factor of safety (FS = resisting forces/driving forces) of the reconstructed preslide slope was calculated using the slope stability model STABR (Duncan and Wong, 1985) under a range of "likely" pore pressure conditions. The results indicate that the preslide factor of safety was close to the threshold value of 1.0 (range 1.0 to 1.2). Although the slump may have been triggered by the rainstorm activity, the actual cause is probably related to pore pressure conditions at the clay-bedrock contact and long-term processes such as cutbank erosion at the toe of the slope and fissure development in the upper, over consolidated clay.

B1b: LATE QUATERNARY GLACIAL TO MARINE SUCCESSIONS IN THE CENTRAL ST. LAWRENCE LOWLAND
Cyril G. Rodrigues
University of Windsor
Windsor, Ontario N9B 3P4
The Central St. Lawrence Lowland includes the area between the Ottawa and St. Lawrence Rivers, straddles the St. Lawrence as far as Quebec City, and extends a short distance beyond the north shore only (Bostock, 1970). Marine water from the Atlantic Ocean inundated the Central St. Lawrence Lowland and Champlain Valley during the final retreat of the Laurentide Ice Sheet from eastern North America, forming the Champlain Sea (Fig 1.) The purpose of this paper is to describe the lithologic and invertebrate faunal successions at two sites in the lowland and to discuss the significance of the successions.

STOP 1. Sparrowhawk Point Site
A ten-metre section of glacial and marine sediments is exposed in the shore cliffs on the south side of the St. Lawrence River between Ogdensburg and Waddington (Fig. 1). The sediments are divided into the following units, (1) massive stony till, (2) rhythmically laminated silt and clay ("varves"), (3) massive mud, and (4) sand (Fig. 2). Unit 1 is equivalent to the Fort Covington Till of MacClintock and Stewart (1965) and is overlain disconformably by Unit 2. The contact between Units 2 and 3 is gradational and the contact between Units 3 and 4 is abrupt. The succession from till to massive mud was also reported by MacClintock and Stewart (1965) and Terasmae (1965) from sections exposed near Cornwall during the St. Lawrence Seaway Project.
Unit 1 is unfossiliferous. Ostracodes are present in Units 2, 3, and 4. Foraminifers are absent in Unit 2 and are present in Units 3 and 4. Invertebrate macrofossils are common in Unit 3 and in the lower part of Unit 4. Portlandia arctica (Gray) is the most abundant microfossil in Unit 3 and is accompanied by Cylichna alba Brown, Macoma calcarea (Gmelin), and Hiatella arctica (Linne). Macoma-balthica (Linne) is present in the lower part of Unit 4.
Radiocarbon dates, 11 900 ± 100 years BP (GSC-3767) and 11 300 ± 100 years BP (GSC-3788), were obtained for shells of Portlandia arctica from the lower part of Unit 3 and for shells of Macoma balthica from the lower part of Unit 4 respectively (Rodrigues and Richard, 1985). At one spot along the shore the laminated sediments are truncated and underlain by massive mud which in turn is underlain by laminated sediments. Rodrigues (1987) proposed that the presence of massive mud below laminated sediments is related to post depositional slumping. Radiocarbon dates of 11 900 ± 100 years BP (GSC-3767) for Portlandia arctica from the lower part of the massive mud overlying the laminated sediments and 11 900 ± 140 years BP (GSC - 4044) for the same pelecypod species from the massive mud below the laminated sediments, are consistent with the slumping hypothesis.
Three ecozones are recognized on the basis of foraminiferal and ostracode assemblages from 30 samples which were collected from 6 m of section (Fig. 2). Ecozone 1 is characterized by the ostracode Candona subtriangulata Benson and MacDonald and is restricted to the rhythmically laminated silt and clay (Unit 2). Ecozone 2 contains low numbers of the foraminifer Elphidium excavatum (Terquem) forma clavata Cushman and Candona subtriangulata; it is associated with the gradational interval between Unit 2 and the massive mud (Unit 3). Elphidium excavatum forma clavata-dominant foraminiferal assemblages characterize Ecozone 3. The foraminifers Cassidulina reniforme Norvang, Haynesina orbicularis (Brady) and Polymorphinids (species of the Family Polymorphinidae) are also present in Ecozone 3. The ostracodes Cytheromorpha macchesneyi (Brady and Crosskey) and Cytheropteron pseudomontrosiense Whatley and Masson are present throughout Ecozone 3, whereas Cytheropteron paralatissimum Swain occurs in the lower part and Roundstonia globulifera (Brady) occurs in the middle and upper parts of Ecozone 3. Portlandia arctica is the most common invertebrate macrofossil in Ecozone 3.
The laminated sediments (Unit 2) characterized by Candona subtriangulata (Ecozone 1) were deposited in a glacial lake which occupied the area during early stages of ice retreat (Fig. 3). The interval between Unit 2 and the massive mud (Unit 3) containing the Elphidium excavatum forma clavata - Candona subtriangulata assemblages (Ecozone 2) were deposited in low salinity bottom-water during the early part of the marine episode. The salinity of the bottom-water was highest (<25 o/oo) during deposition of Unit 3 which is characterized by Elphidium excavatum forma clavata - dominant foraminiferal assemblages and the pelecypod Portlandia arctica (Ecozone 3).
The inferred freshwater environment for the rhythmically laminated till and clay ("varves") is based on the modern and fossil occurrences of Candona subtriangulata. Congeners of Candona live in freshwater environments, i.e. lakes and rivers (Delorme, 1970 ). Identical Candona subtriangulata-assemblages were reported from the Late Pleistocene Sreboygan Member of the Lake Michigan Formation (Burke, 1987). The presence of Canadona subtriangulata and Elphidium excavatum forma clavata in Ecozone B (Fig. 2) indicates that C. subtriangulata can survive in marine environments characterized by low salinity. This does not imply that the varve-like rhythmites containing Candona subtriangulata were deposited in a marine environment. The distinction between freshwater and marine environments is based on the total fossil assemblage, rather than the presence of a single species in the assemblage. Thus, assemblages containing only Candona subtriangulata are related to freshwater conditions, whereas assemblages containing C. subtriangulata plus marine ostracodes and/or foraminifers are related to low salinity conditions during the early part of the Champlain Sea episode in the Central St. Lawrence Lowland. Cronin (1977) described assemblages containing 2, marine ostracodes, and foraminifers from deposits near the maximum extent of the Champlain Sea in the Champlain Valley. He also concluded that the assemblages are related to low salinity conditions during the early part of the marine episode.

STOP 2. Casselman Site
About 17 m of glacial and post-glacial sediments are exposed along the west bank of the South Nation River, northwest of the town of Casselman (Fig. 1). The sediments rest unconformably on Ordovician carbonate rocks. The glacial and post-glacial sediments are divided into the following units, (1) till, (2) rhythmically laminated silt and clay ("varves"), (3) massive mud, and (4) red- and grey-banded mud (Fig. 4) . The contacts between Units 2 and 3 and Units 3 and 4 are gradational. The succession from Unit 2 to Unit 4 was described by Fransham and Gadd (1977) and Gadd (1977, 1986) from boreholes in the deeper parts of the lower Ottawa Valley.
Unit 1 is unfossiliferous. Foraminifers are absent in Unit 2 and are present in Units 3 and 4. Ostracodes occur in Units 2, 3 and 4. The pelecypods Macoma calcarea, Mytilus edulis Linne, Portlandia arctica and Yoldiella sp., and the sponge Tethya logani Dawson are present in Unit 3. Invertebrate macrofossils were not observed in Units 2 and 4.
Six ecozones are recognized on the basis of foraminiferal and ostracode assemblages from 22 samples which were collected from Unit 2 and Unit 3 and the gradational interval between the units (Fig. 4). The varve-like rhythmites (Unit 2) and the lower part of the gradational interval between Unit 2 and the massive mud (Unit 3) are assigned to Ecozone A which is characterized by the ostracode Candona subtriangulata. Foraminifers and ostracodes are present in low numbers in Ecozone B which is restricted to the upper part of the gradational interval between Unit 2 and Unit 3. Ecozones C to F are associated with Unit 3. Cassidulina reniforme and Islandiella helenae Feyling-Hanssen and Buzas are the characteristic species of foraminiferal assemblages from Ecozone C. Cassidulina reniforme, Elphidium excavatum forma clavata and Haynesina orbicularis are the most abundant species in Ecozones D and E. The abundance of Cassidulina reniforme is lower and that of Elphidium excavatum forma clavata is higher in Ecozone E by comparison with their abundances in Ecozone D. Cassidulina reniforme is absent and Haynesina orbicularis is the most abundant species in Ecozone F. Portlandia arctica is the most common invertebrate macrofossil and ostracodes are rare in Ecozones C to F. Foraminifers and ostracodes are present in low numbers in the upper part of Unit 3 and in the lower part of the color-banded mud (Unit 4).
The Candona subtriangulata assemblages of Ecozone A are related to fresh water conditions (Fig. 5). Marine conditions are inferred for Ecozones B to F which are characterized by foraminifers. Ecozone B represents a transition from freshwater to maximum salinity conditions. Salinity was <25°/oo in Ecozone Band from the upper part of Ecozone D to Ecozone F. Maximum salinity conditions (25-34°/oo) existed from Ecozone C to the lower part of Ecozone D.
The rhythmically laminated silt and clay (Unit 2) was deposited in a glacial lake which occupied the area during the early stages of deglaciation. The massive mud (Unit 3) and the upper part of the gradational interval between Unit 2 and Unit 3 were deposited during the Champlain Sea episode. Low salinity water replaced freshwater during the deposition of the gradational interval between Unit 2 and Unit 3. Maximum salinity conditions were followed by decreasing salinity during deposition of Unit 3. The lower part of color-banded mud (Unit 4) was deposited under relatively low salinity conditions during regression of the Champlain Sea.
A radiocarbon date of 11 460 ± 70 years BP (TO-702) was obtained for foraminifers from the base of Unit 3, i.e. the base of the maximum salinity Ecozone C (Fig. 5). The date indicates that maximum salinity water arrived at the Casselman site ca. 11 500 to 11 400 years BP. TO-702 is younger than the date of 11 900 ± 100 years BP (GSC-3767) for Portlandia arctica from the lower part of the massive mud (Unit 3, Ffg. 3) which overlies varve-like rhythmites at the Sparrowhawk Point Site.

B2: DIKES OF THE NORTHEAST ADIRONDACK REGION - INTRODUCTION TO THEIR DISTRIBUTION, ORIENTATION, MINERALOGY, CHRONOLOGY, MAGNETISM, CHEMISTRY, AND MYSTERY
Y.W. ISACHSEN and W.M. KELLY
C. SINTON and R.A. COISH
Middlebury College
M. T. HEIZLER
SUNY Albany
INTRODUCTION AND SCOPE
More than 1300 dikes in the Adirondack region have been compiled on a map at 1:250,000 (Isachsen and Wright, in press). Figure 1 is a severe reduction of this map. While 1300 may seem a large number of dikes, the sparsity of reck exposures in the region suggests that it represents at most a few percent of the total number actually present. Most dikes are exposed over a length of only a few meters or less, and are a meter or so thick. Several, however, are exposed intermittently for distances up to 15 km, and are as much as 10 m thick. Twenty-four types are represented, five of which are metamorphic. Mafic dikes clearly predominate. Their prominence, in decreasing order, using the names given in the literature, are as follows: diabase, "mafic dike", basalt, gabbro, metagabbro, metadiabase, hypersthene metadiabase, and garnet metadiabase. Next most prominent are lamprophyres and granite pegmatite dikes. Rose diagrams of dike orientations (Isachsen and Wright, in press) show these dominant strike directions: 1) NNE-NE for the basalt, diabase, gabbro and "mafic" dikes, 2) WNW to E-W for the lamprophyres, and 3) NS to NNW for the metamorphic dikes. The northeasterly strikes of most of the unmetamorphosed mafic dikes corresponds to the predominant trend of faults and zero-displacement crackle zones that account for the great number of linear valleys in the southeastern half of the Adirondacks (Isachsen and McKendree, 1977; Isachsen and others, 1983). The easterly-westerly trends of the lamprophyre dikes correspond to the trends of similar dikes in Vermont . (McHone and Corneille, 1980, McHone, 1984). Their radiometric dates are similar as well.
This trip will include two stops to see lamprophyre dikes and one to see the most impressive concentration of dikes in the Adirondacks - the Rand Hill dike swarm. Here, more than 100 dikes, up to 180 m in exposure length, are exposed in three cross-cutting orientations. Diabase, olivine diabase, and trachyte porphyry dikes intrude gabbroic anorthosite gneiss.
Subjects for discussion will include: dike orientations vs regional fracture patterns, magnitude of extensional strain, dike propagation mechanisms, relative and radiometric ages (and problems), paleomagnetism and apparent polar wander path, geochemical characterization, and plate tectonic inferences
"For the structural geologist, eroded dykes may be viewed as the remnants of full-scale tests of the fracture strength of the Earths crust. If field observations are properly interpreted, they will provide important constraints on the process of dyke emplacement." David Pollard, 1987

B2: DIKES OF THE NORTHEAST ADIRONDACK REGION - INTRODUCTION TO THEIR DISTRIBUTION, ORIENTATION, MINERALOGY, CHRONOLOGY, MAGNETISM, CHEMISTRY, AND MYSTERY

Pass Plattsburgh Quarries on left.

STOP 1. Lamprophyre Dikes
Two lamprophyre dikes cutting a tilted fault block of Crown Point Limestone (Middle Ordovician) of the Chazy Group. The dikes strike N55-73W and dip 83-85 NE, parallel to the prominent joint set here. They are about 50 cm thick and display chilled margins. They contain calcite amygdules, clinopypoxene phenocrysts and local xenoliths of gabbroic metanorthosite. The subject of lamprophyres has recently been reviewed by Rock (1987). The name covers a number of alkalic rock types that form dikes or sills, and rarely lavas. They are defined by their content of abundant euhedral to subhedral phenocrysts of mafic minerals such as olivine, amphibole, biotite, clinopyroxene, apatite or oxides, but not felsic phenocrysts; the groundmass may be mafic, felsic or glassy. Silica content and Na/K ratio vary widely.
In the field, lamprophyres may be difficult to distinguish from diabase dikes, but a careful examination of textures shows lamprophyres to lack the familiar ophitic or diabasic texture with its visible laths of plagioclase. Instead, lamprophyres have a pronounced panidiomorphic-granular (sugary) texture with mafic phenocrysts of various sizes in a fine-grained alkali groundmass. Spherical, calcite-bearing amygdules are common. They, and mafic phenocrysts, may weather preferentially to produce a pitted weathering surface. Although similar weathering also characterizes olivine diabase and olivine basalt, these show the lath-shaped crystals of plagioclase, commonly of phenocryst size.
The dikes at this locality are rich in amygdules filled with calcite. One dike shows an equigranular texture of biotite, plagioclase laths, subhedral and skeletal opaques, and olivine micro-phenocrysts, with some apatite and amphibole. Two samples taken from the southern side of the road show a characteristic porphyritic, texture, with large euhedral to subhedral phenocrysts of zoned clinopyroxene. The groundmass consists of essential biotite, plagioclase, subhedral opaques, apatite, and possibly amphibole. Alteration of the rock is minimal, but some of the mafic phenocrysts have been altered to chlorite and calcite. The presence of rounded anorthosite xenoliths suggests possible contamination of the magma.
From the whole rock chemistry (Table 1) these rocks can be classified as alkaline lamprophyres, according to Rock (1987). Note the high concentration of alkalis, particularly K2O. The SiO2 contents of the dikes are similar to those of the camptonites of the Champlain Valley studied by McHone and Corneille (1980). Rock (1987) notes that lamprophyres have distinctly higher concentrations of Ba and Sr relative to other silicate igneous rocks, and this is shown here. The lamprophyres have Sr values ranging from 879 to 2016 ppm and Ba values of 800 to 1631 ppm (Table 1), as compared to the diabase dikes at Stop 2 (Rand Hill) which have Sr values of 334 to 706 ppm and Ba values of 373 to 496 ppm (Table 1).
These dikes are probably related to other lamprophyres of Mesozoic age found within the Champlain Valley which have been associated with the alkalic syenite gabbro intrusions of the Monteregian Hills of Quebec (e.g. McHone and Corneille, 1980; deBoer and others, 1988).

STOP 2A. Rand Hill Dike Swarm
Road cuts along Rt. 190 immediately south of Murtaugh Hill Road. Examination will be made first of the roadcuts here which provide fresh 3D exposures of the several dike types that make up the Rand Hill dike swarm. Very extensive exposures will then be examined in the largely open area that extends half a kilometer to the west, STOP 2B. The intruded country rock is gabbroic anorthosite gneiss.
The Rand Hill swarm is located at the eastern foot of Rand Hill. It was first described by H.P. Cushing (1898) who called attention to three localities in the northeastern Adirondacks with "exceedingly numerous dikes": Rand Hill, Dannemora Mountain, and the shores of Upper Chateaugay lake. The Rand Hill dikes are nearly all vertical or sub-vertical, and consist of three types: diabase, olivine diabase, and trachyte porphyry (the "red syenite porphyry" of Cushing). Cushing noted that the thinner diabasic dikes are almost without exception porphyritic, and that the same applies to the borders of the wider dikes. In thin section, he found two generations of plagioclase and augite but only one of olivine. Biotite was observed in about 25 percent of the dikes.
Nineteen dikes are intruded into gabbroic meta-anorthosite in these road cuts. Their thicknesses range from 1 cm to 7 m. Some contain xenoliths and blocky plagioclase xenocrysts derived from incorporated host rock. The dikes are chilled at both their margins and along their contacts with xenoliths.
The distribution, dimensions, orientations, and classification of all dikes thicker than 40 cm is shown in Fig. 10. Dike identifications are based on field examination, including staining for K-feldspar, and then corroborated by thin section study. Numerous geochemical analyses were made in order to evaluate possible plate tectonic settings of the intrusions, as was discussed under Geochemistry.
The dominant dike type at Rand Hill is olivine diabase. Typically, altered olivine phenocrysts are concentrated in the central part of the dike by flow differentiation. The phenocrysts are altered to blackish serpentine clots (check hardness). The selective weathering of these clots accounts for the characteristic pitted surface. Although the olivines, with a specific gravity of 3.3 are concentrated in the centers of the dike by flow differentiation, the less dense plagioclase phenocrysts with a specific gravity of 2.7 are not; in fact they are generally concentrated in the finer grained border zones.
A 2.4 m wide trachyte porphyry dike with flow-aligned laths of Carlsbad-twinned plagioclase and K-feldspar is exposed near the southern end of the roadcut (sample numbers 6182-6188). It is typical of this group, although the color of these dikes vary: they may be either red, greenish, or gray to black. Cushing (1901) identified 19 trachyte porphyry dikes at Rand Hill and summarized their petrography. The essential minerals are microperthite and biotite, and accessory minerals are magnetite or specular hematite, hornblende, quartz, albite, orthoclase, microcline, apatite, and sphene; secondary minerals are chlorite, calcite, sericite, epidote,and hematite. Microperthite and biotite or chlorite are the only two minerals found in all dikes examined. Staining here shows that both K-feldspar and plagioclase laths are up to 1 cm long but vary in size and abundance. Total feldspar makes up about 55 percent of the rock, chlorite-altered biotite about 40 percent, and opaque minerals plus apatite needles the remainder. Note small blocky xenocrysts (?) of gray plagioclase and incorporated angular fragments of mafic dike rock. As discussed under Geochronology and Geochemistry, the diabase and trachyte dikes at Rand Hill are coeval, and presumably derived from a common magma source.
The northern contact of this dike is faulted, as indicated by shearing of the dike (probably cataclasis) and the introduction of anastomosing, hematite-stained calcite veins.
A small xenolith(?) of coarse-grained diabase or fine-grained gabbro (sample site 6194) adjoins the 7 m-wide olivine diabase dike at its southern margin (Fig. 10). The xenolith(?) is crosscut by a thin diabase dike that is chilled against it.
Relict ophitic texture is visible in the xenolith(?) although the rock is pervasively stained by oxides. It contains about 50 percent subhedral plagioclase and 20 percent relict orthopyroxene, most of it altered to serpentine and chlorite. Its similar composition (Table 1) suggests that it may be a cognate inclusion (autolith) brought up from a deeper level in the same magma system.

STOP 2B. Rand Hill Dike Swarm
Turn left (west) onto Murtaugh Hill Rd. and park. Walk across the road onto open hillocks that expose at least 100 mafic dikes in gabbroic anorthosite gneiss (Fig. 11). This locality, at the eastern foot of Rand Hill, is by far the best exposed mafic dike swarm in the Adirondacks. Dikes are intermittently exposed for lengths in excess of 150 m. Their thicknesses range up to at least 5 m. Ramble westward, in a zig-zag course across the dike swarm to the end of the exposure area about 350 m to the west. Exposures extend beyond the map area to the south and west .
Dikes here have three trends (Fig. 11), all crosscutting the N30E strike of foliation in the host rock. The large irregular EW dikes bear alkali feldspar as shown by Kf staining. They are the "syenite porphyry dikes" of Cushing (1898). The N60-70E dikes are porphyritic olivine diabase dikes that show clear evidence of flow differentiation. Olivine phenocrysts that formed at depth have been concentrated in the centers of the rising magma by flow. The olivines are generally highly to completely altered, and weather out to produce the characteristic pitted surface. A N40E set is sparsely represented.
Note these interesting features of dikes during your ramble, and recall that basaltic dikes are emplaced almost instantaneously, the average velocity of propagation being 0.4-0.5 m/sec (Delaney and Pollard, 1982):
1) Chill borders against host rock.
2) Dikes may be straight, stepped, segmented.
3) Joints within the dikes do not penetrate the host rock: cooling cracks? compression features?
4) Dike walls may be even, irregular, cusped, and may have horn-like extensions or irregular apophyses.
5) Dike terminations may be tapered, blunt, rounded or irregular, and may have narrow extensions or "squirts".
6) Some dikes are composites of two sheeted dikes. The boundary between such dike pairs is a thin line of preferential erosion between the two adjacent chill borders. In at least one locality southwest of the mapped area, a sheeted dike pair bifurcates along strike around a slabbed inclusion of wall rock.
7) Relative age and direction of opening can be determined by analysis of dike intersections. These and en echelon configurations can also permit reconstruction of stress axes during emplacement. En echelon dikes indicate a reorientation of principal stress trajectories at the fingered propagation front of intrusive sheets (e.g. Delaney and Pollard, 1981).
8) Dike-parallel joints generally are absent in the host rock. This suggests that emplacement was not along pre-existing fractures but along an opening created and propagated by magma pressure in advance of the dike tip, in a plane perpendicular to the least compressive stress axis.
9) Concentration of olivine phenocrysts toward the center by flow differentiation.
10) Concentration of plagioclase phenocrysts near the margins rather than in the center.
11) Flow-aligned plagioclase laths indicate direction of magma propagation.
12) The amount of extensional strain produced by intrusion was significant in this swarm, reaching a magnitude of 18.8 percent north of Station C. A number of the dikes measured in this section could not be shown on the map of Fig. 11 because of its small scale.

STOP 3. Camptonite Dike
NO HAMMERS; cameras instead. Xenolith-filled augite camptonite dike, Martin Bay. Private property; permission required of landowner.
The dike makes a low garden wall that strikes N80W. It is 0.5 m thick, and exposed over a length of 7m.
The place to concentrate on, however, is along the shore, where an isolated block of dike rock, 70 cm thick, has weathered out of its host rock, the Cumberland Head Argillite (Middle Ordovician). Note the parallel dike walls bordering the 10 cm-thick fine-grained chill margins. Note also the striking number of xenoliths concentrated in the 50 cm-thick central part of the dike by flow differentiation. These subangular to round xenoliths constitute about 50 percent of the dike, and appear megascopically to have sharp boundaries with the dike material. They range in diameter from 1 mm to 9 cm, most exceeding 2 cm. Lithologies include pyroxene syenite gneiss, gabbroic metanorthosite, metagabbro, and trachyte, as well as one ultramafic xenolith and a round xenocryst of hornblende. Note the slight flow alignment of elongate xenoliths.
In crushed grains and thin sections D.H. Newland (in Hudson and Cushing, 1931) found that the syenitic inclusions contain microcline, microperthite, much-altered greenish pyroxene, and iron-stained grains that may be hornblende, biotite or both, along with small amounts of quartz, and occasional garnet crystals. The dike material is a fine-grained holocrystalline lamprophyre with phenocrysts of clinopyroxene and olivine in a felted groundmass of plagioclase, augite and opaque oxides. Staining indicates about 20% K-feldspar in the groundmass.
The xenoliths are typical of Adirondack rock types, so their source along the path of intrusion is easy to visualize. What is unusual is the fact that 1) among the 250 lamprophyre and trachyte dikes in the lake Champlain area of New York and Vermont (McHone and Corneille, 1980) such xenoliths are extremely rare, and 2) the xenoliths are so remarkably rounded. Does the abundance in this one dike suggest that the magma advanced through a brecciated and fragmented fault zone? through a basal Paleozoic conglomerate? If the latter, the xenoliths are considerably larger than the pebbles in the rare exposures of basal Potsdam in the eastern Adirondack region. If the former, was the rounding produced by mechanical abrasion of incorporated breccia? by melt abrasion or partial resorption?
This particular dike gives a K/Ar date of 131+5 Ma (Greg McHone, written comm., 2-19-85) which falls in the age range of the NY-Vt. lamprophyres and corresponds to the oldest ages of the Monteregian Hills intrusions of Quebec (McHone and Corneille, 1980).
A similar xenolith-laden dike is well exposed farther south, in Indian Bay, Willsboro Point. It is an augite camptonite dike, more than 2 m thick, intruding Canajoharie Shale (Middle Ordovician). It is pictured and described by Buddington and Whitcomb (1941). McHone (written comm., 2-19-85) reports a K/Ar age of 119+5 for this dike.
The narrow range of strike of the lamprophyre and trachyte dikes, in the Lake Champlain valley, as well as the consistency of Cretaceous ages, suggest that they are a cogenetic suite, perhaps a mafic-felsic pair formed by an immiscible liquid mechanism from mantle-derived camptonitic magma (McHone and Corneille, 1980)

B3: MIDDLE ORDOVICIAN STRATIGRAPHY AND SEDIMENTOLOGY - SOUTHERN LAKE CHAMPLAIN VALLEY
Bruce Selleck
David Maclean
Con-Test, Inc.
The Middle Ordovician strata (Chazy, Black River and Trenton Groups) of the Champlain Valley record the latter stages of passive margin deposition on the early Paleozoic continental margin of eastern North American. The onset of foredeep development, in response to loading of this portion of the continental margin during the late Medial Ordovician Taconic orogeny, in also recorded in the this section by development of generally deepening-upward facies patterns in the Black River and Trenton Groups. The goals of this trip are to examine these units in the Southern Champlain Valley, interpret the depositional environments represented, and to assess the importance of tectonic controls upon regional facies patterns.

STOP 1. Westport, New York
These roadcuts expose approximately 24 meters of the Glens Falls Formation of the Trenton Group. Stratigraphically, we are located in the middle and upper portion of the Glens Falls, within the zone of Cryptolithus tesselatus. The Glens Falls at this exposure consists of two major facies. The lowermost three meters, and the uppermost ten meters of the section are characterized muddy packstone beds, often capped by Chondrites burrows. The limestone beds are separated by thin calcareous shale interbeds. Each limestone bed consists of a couplet, with the basal portion of the bed characterized by whole-shell and fine bioclastic grainstones, and the upper portion consisting of slightly fossiliferous mudstones. This facies is interpreted as a storm surge ebb current deposit, resulting from the turbidity current-like flows generated as storm wave surge resuspended mud and shell debris on shallower portions of the shelf. Fossils are relatively abundant in this facies, and include the typical Trenton brachiopods, bryozoans and rare trilobites.
The middle ten meters of the exposure consists of somewhat more regularly bedded argillaceous micrites, with relatively thick (2-20 cm.) shale interbeds. The argillaceous mudstone beds show limited size grading, and are often highly bioturbated. Fossils are scarce in the limestone beds, but interbedded shales may contain bryozoans and other bioclasts. This facies is interpreted as a hemipelagite, resulting from deposition of suspended lime and terrigenous mud in a setting unaffected by wave and storm driven currents. The abundant shales in this facies indicate a sudden increase in the influx of terrigenous sediment to the shelf at this time. Insoluble residues from the limestone beds often contain abundant silt-size euhedral quartz, plagioclase and sanidine crystals, suggesting that volcanic ash was supplied, perhaps from the Taconian island arc system to the east. This facies is traceable to the east in sections on the Vermont side of Lake Champlain.

STOP 2A. Redoubt Fort east of N.Y. 8
Approximately 6 meters of variously burrowed, slightly dolomitic, thin to medium bedded bioclastic packstones are exposein this section. The dolomite occurs in shaly weathering wisps and laminae and in burrow fills. Abundant "Girvanella" algal oncolites (algal accretionary grains) are present in beds approx. 4 meters from the base of the section. Rounded dark calcite grains (abraded gastropod fragments) form the cores of the oncolites, and are scattered in other beds. Fossils are relatively abundant and best seen on bedding surfaces. Trilobite fragments, brachiopods, bryozoans, pelmatozoan plates, nautiloids and large Maclurites magnus are present. The relatively high faunal diversity, abundant lime mud and burrowing argue for a normal marine, low energy shallow subtidal carbonate environment. A possible modern analogue is found in the mixed mud and sand shelf to the west of the emergent Andros Island tidal flats, as described by Bathurst (1971) and Purdy (1963). The 5-10 cm thick beds of "oncolite conglomerate" and other more well-sorted grainstone beds may represent periods of storm winnowing of the bottom, with transportation of abraded sand from adjacent sand shoal environments (e.g. Locality 2B). The wavy, irregular dolomite laminae appear to result from post-depositional dolomitization of lime mud, followed by compaction and local pressure solution of calcite, producing irregular, clay- and dolomite-rich stylocumulate seams. Preferential dolomitization of burrows may be due to contrasts in porosity or permeability of burrow-fill versus burrow-matrix sediment. The burrow-fill sediment may have retained permeability longer during diagenesis, permitting pervasive dolomitization. This sort of fabric selective dolomitization is common throughout the Chazy and Black River Groups in the southern Lake Champlain Valley.

STOP 2I. Exposures of Glens Falls is separated by intervals of beach gravels
STOP 2I. The contact between the Orwell Formation and the basal Glens Falls Limestone is covered by beach gravels. The lower 16 meters of the Glens Falls lies below the first occurrence of Prasopora. Cryptolithus appears approximately 20 meters from the base of the section. Thus, only the uppermost 10 meters of section are time equivalent to the Westport exposures seen at Westport. The Glens Falls at Crown Point consists of the same muddy packstone facies seen at Westport. Limestone beds typically have shelley basal portions which rapidly grade upward into muddy packstones. Thin calcareous shale interbeds define the bedding. This facies is again interpreted as storm surge-ebb current deposits with intervening shale suspension rainout. There is a slight tendency for the bedding style in the lower portion of the section to be more wavy or lenticular, perhaps suggesting that storm wave scour occurred. The upper portion of the section is slightly thinner bedded, and bryozoans become relatively more abundant. Fine examples of the various trace fossils which characterize this facies are to be found on the bedding surfaces, including Chondrites.
Fossils are abundant and rather diverse. Trilobites (usually fragmental) include Isotelus, Flexicalymene and rare Cryptolithus; the brachiopods Sowerbyella, Rafinesguina; Dinorthis and Dalmanella; bryozoans Prasopora, Eridotrypa and Stictopora; plus orthocone cephalopods and pelmatozoan debris. Gastropods, which are so abundant in the underlying Orwell limestone are exceedingly rare in the Glens Falls.
The Glens Falls here records the continuing deepening of the Middle Ordovician shelf that began with the deposition of the Phytopsis lime mudstones at Stop 2F. The shale interbeds and generally more argillaceous character of the Glens Falls document increase in terrigenous mud input, perhaps derived from the rising Taconic Orogenic complex to the east. Quartz and feldspar grains of volcanic origin are also common in insoluble residues of Glens Falls limestones, suggesting increased eruptive activity at this time.

B4: GEOLOGY OF THE WILLSBORO WOLLASTONITE MINE
JAMES F. OLMSTED
S.U.N.Y. Plattsburgh
Plattsburgh, NY 12901
PAUL W. OLLILA
Poughkeepsie, NY
The wollastonite deposits of this region are the world's major source of of this important industrial mineral. Several occurrences of coarse wollastonite gneiss that is potential ore are known throughout the Willsboro and Ausable Forks quadrangles but to date only this and the Lewis deposit have been exploited. We have chosen this, now inactive, mine as the site for the trip because of excellent exposure of related rock types as well as unmatched display of structural and metamorphic features. The presently active Lewis mine is located at the other end of a fifteen kilometer long belt of metasediments that overlie the Westport anorthosite dome. Topics of particular interest are the mineralogy of the wollastonite unit, petrography of related units, mineralogical and textural relationships at contacts and the structural geology of the metasedimentary belt.
The trip will consist of a walking traverse in which we will study the lower half of the Willsboro metasedimentary belt. We begin at the lower portal of the mine and proceed north about 600 m. where we encounter the base of the "Midsection Anorthosite" a thick sill-like unit that divides the section into lower and upper parts. We will then cross the section in a westerly traverse to a point about a kilometer west of the lower portal where we will examine the wollastonite and the amphibolitic unit at the top of the Westport anorthosite dome. We then return along strike to the mine site where you can collect samples of the ore and related rocks. The entire hike is about three kilometers through wooded terrain but with one exception (a steep descent) it is not particularly difficult.
GEOLOGIC SETTING
Throughout the northeast Adirondack Mountains metasedimentary shelf type deposits are in contact with anorthosite dome-like structures. The infolded metasedimentary rocks include marble, calcsilicates of a variety of compositions, quartzite and gneisses that range from amphibolite to quartzo-feldspathic in composition. Many of the latter two are thought to be of volcanic origin although some may have been intrusive. Emplaced into these units are intrusive rocks that range in composition from granite to gabbro and include anorthosite and related rocks. All of these have been subjected to granulite facies metamorphism which has altered the primary petrographic and structural features. Buddington and Whitcomb (1941) indicate the temporal sequence to begin with Grenville metasediments intruded by anorthosite, gabbro and granitic rocks all of which were deformed and metamorphosed. Our mapping indicates the metagabbro to be the younger rock type. It occurs as dikes and sills and cuts the other three rock types. In this area we have mapped a large metagabbro sill that has intruded the metasediments above the wollastonite gneiss. We will examine its textural and contact relationships with surrounding rocks for the purpose of understanding influence it may have had on their formation.

B4: GEOLOGY OF THE WILLSBORO WOLLASTONITE MINE

STOP 1. Wollasonite Mine
Park on right if gate is closed or continue up road to first portal.
From the east end of the lower portal of the mine we will climb up over the exposed bedrock, carefully examining the rock types as we climb. In the immediate area of the mine they include; wollastonite ore, garnetite, gabbroic anorthosite gneiss, syenitic gneiss and a very mafic appearing calc silicate gneiss. We will point out several structural features as we move up the hill. Higher in the woods we will see evidence of repetition of the wollastonite rock in the form of another garnetite unit. The northernmost extent of the traverse will be indicated by an anorthositic unit that forms a prominent ridge. At this point we turn southwesterly back across the valley where we encounter more mafic calcsilicates, then up the hill to a large exposure of metagabbro. We will continue southwesterly over Bristol Mountain and down into the next valley where we will examine among other things, the base of the wollastonite unit, it upper contact and the underlying rocks of the Westport Dome. We will then walk easterly along strike of the wollastonite unit past the mine area where you may collect ore samples to your heart's content and back to the cars.
Optional stops may include the westward extension of the Willsboro belt where it crosses the Adirondack Northway and the Deerhead location which is another similar wollastonite occurrence that can provide additional structural insight as well as opportunity to examine other rock types in the section.

61st Annual Meeting
Middletown, New York
Field Trip Guidebook
Edited by
Dennis Weiss
Department of Earth and Planetary Sciences
City College of CUNY
Hosted by
Larry O'Brien
Department of Science and Engineering
Orange County Community College
The diversity of the geology of the Lower Hudson Valley and environs is reflected in the breadth of field trips contained in this guidebook for the 6lst Annual Meeting of the New York State Geological Association. Nowhere in New York can one view, in an area of comparable size, such a wide variety of rocks, structures, and sediments representing more than one billion years of Earth history. Evidence of major events in the Earth's history and development ranging from periods of extreme deformation, to times of extensive sedimentation, to the breakup of continents, to the covering of the land by vast ice sheets are contained in the area's geologic sequences. In addition, modern problems in applied geology such as seismic risk and slope stability are also of particular concern.
Several of the field trips retrace the paths their authors led us on at previous meetings of the Association. Howard and Elizabeth Jaffe; Gordon Conally, Les Sirkin, and Don Cadwell; and Bob Finks update information presented at various meetings over the past twenty-nine years. It is with nostalgia that I remember that these were the first trips of the Association that I attended as a student. Moreover, some of you may recognize the art work of Jack Fagan which adorns the cover the guidebook. New views are presented by Pam Brock on the stratigraphy of the Manhattan Prong; by Tony Prave, Moses Alcala, and Jack Epstein on the nature of sedimentation in the middle and late Silurian; and by Alan Kafka, Margie Winslow, and Noel Barstow on the neotectonics of the Lower Hudson Valley region. Clearly, there is continuing interest in the Green Pond Outlier. Larry Malizzi and Alec Gates; Jim Mitchell and Randy Forsythe; and Bob Finks and Michael Raffoni present their respective interpretations of that area's geologic development. Triassic/Jurassic intrusive and extrusive igneous activity is examined by Jeff Steiner and John Puffer, respectively. Over the years the area of the Lower Hudson Valley has been extensively developed and the surficial deposits of the area disturbed. Despite this added difficulty, Les Sirkin, Don Cadwell, and Gordon Connally have been able to complete new studies of the Pleistocene geology of eastern Putnam County and Westchester County. As growth and development of the region have continued, the expansion of its highways has been accompanied by problems of slope stability. Clay Bolton's field trip will examine this concern which, in recent years, has led to catastrophe in several instances. Looking back into prehistory, this region has been occupied by man for over 6,000 years. Phil La Porta's presentation on chert, relates its stratigraphic occurrence to regional archeologic studies. Finally, as our concerns for science education increase, Bill Tucci and Bob Kalin in their "Geologic Climb of Schunnemunk Mountain" present a useful "hands on" teaching exercise for Earth Science teachers.
In closing, I would like to thank the authors of each trip for their effort and cooperation. Without them this guidebook would not be the professional reference and source of information it is. In addition, my gratitude goes to Jack Fagan for finding the time to do the cover of the guidebook, Jim Olmstead and Fred Wolfe for their wisdom and guidance, Larry O'Brien for his uplifting and cheerful support during the editing process, and finally to my wife Susan for patiently enduring the piles of manuscripts and edited texts left all over the house.
Dennis Weiss, Editor October, 1989

A1: STRATIGRAPHY OF THE NORTHEASTERN MANHATTAN PRONG, PEACH LAKE QUADRANGLE, NEW YORK-CONNECTICUT
PAMELA CHASE BROCK
Queens College and the Graduate Center of the City University of New York
The purpose of this trip is to consider the stratigraphy of the Manhattan Prong along the New York-Connecticut border, in the Peach Lake quadrangle (Fig. 1). Recent mapping in this area has suggested that a major stratigraphic rev1s1on is necessary. Overlying the Grenvillian rocks of the Fordham Gneiss and below the magnesian marbles of the Cambro-Ordovician Inwood Marble, a traceable suite of metasedimentary and metavolcanic rocks appears to exist. This suite, here informally named the "Ned Mountain Formation", includes the K-feldspar rich quartzites typical of the "Lowerre Quartzite"; but it also contains a variety of other lithologies, all of which have previously been assigned to either the Fordham Gneiss or to post-Lowerre Paleozoic units. Ways in which rocks of the "Ned Mountain Formation" can be distinguished from other units will be pointed out on the trip and in the text.
Recognition of this new, expanded, Late Precambrian to Early Cambrian unit will have important implications both for the rift-to-drift stage of geological history and (by its map scale distribution) for Paleozoic structures in the Manhattan Prong.

A1: STRATIGRAPHY OF THE NORTHEASTERN MANHATTAN PRONG, PEACH LAKE QUADRANGLE, NEW YORK-CONNECTICUT

Station 1A. Fordham Gneiss and overlying Basal Member of the "Ned Mountain Formation"
The Yfiii member of the Fordham Gneiss is exposed on this hill. It consists of well-layered and compositionally heterogeneous coarse-grained, orthopyroxene-bearing gneisses. The scale of compositional layering ranges from about 2 cm to a meter. Some layers are highly leucocratic, dark layers are generally hornblende-rich. On close inspection, pitted and rust-stained orthopyroxenes can be seen on the weathered surface of the outcrop.
Here the Fordham largely retains its characteristic, poorly foliated Grenvillian texture. Locally, lineation defined by mafic minerals is evident. The effects of Taconian metamorphism can be seen in thin section: many orthopyroxenes are surrounded and embayed by cummingtonite and/or hornblende. Some pyroxene-bearing granite is present along the hill slope.
A number of small shear zones cut discontinuously across the gneisses. These seem to be related to an episode of post-Taconian shearing seen elsewhere in the northern Manhattan Prong. Age constraints from these areas suggest a Carboniferous age for the post-Taconian deformation (Brock and others, 1985; Brock and Brock, 1985 a & b).
After examining the Fordham, follow south along the cliff base for 60 to 100 meters to see the Basal Member of the "Ned Mountain Formation".
Here the Basal Member of the "Ned Mountain Formation" is a fissile, rusty-staining, graphitic granofels. The rocks are medium-to fine-grained, and contain quartz-K-feldspar-plagioclase-biotite-graphite±garnet. The tough Fordham gneisses form the crown of the hill, and the softer granofelses lie along its southern flank.
Biotite in the graphitic granofelses is concentrated into close-spaced (though discontinuous) streaks; as a result, the rocks tend to break into thin folia. This habit, and their K-feldspar-richness, distinguish the "Ned Mountain" granofelses from similar rocks in the Fordham and the Walloomsac. The graphitic, rusty-weathering granofels of the Fordham unit Yfy contains no K-feldspar and little biotite. Walloomsac granofelses are typically quartzplagioclase-biotite-graphite rocks containing little if any K-feldspar and breaking in a slabby fashion.
Fordham lithologies are truncated against the "Ned Mountain Formation". Where ZEnb is first seen, it is in contact with heterogeneous, layered gneisses; following the unconformity ∼30 meters southwest, largely leucocratic, homogeneous Fordham gneisses are against it; after another hundred meters large amphibolites lie at the unconformity; still further southwest, leuco-to mesocratic gneisses are in contact with the graphitic granofelses of ZEnb. Fordham gneisses adjacent to the unconformity tend to show the effects of Taconian metamorphism and deformation more than they do elsewhere. They are richer in biotite and have a better-developed foliation.
After finishing with this station, cross back to the east over the old dam. (The dam stands above the stream and swamp to the south of the hill.) Retrace your steps along the trail southwards for approximately 100 meters to the junction with a branch trail that climbs up to the east. Follow it east for ∼30 meters (Fig. 6). Then turn south off it to the outcrops of Station lB.

Station lB. Fordham Gneiss, Unit Yfv
Here Unit Yfv of the Fordham consists of well-layered, medium to coarse-grained, melanocratic to leucocratic gneisses. Plagioclase-quartz-hornblende-biotite-pyroxene±cummingtonite gneisses and amphibolite are present in the first outcrop. Rocks still showing the distinctive assemblage of YFv, garnet-clinopyroxene-plagioclase±orthopyroxene, can be seen in the outcrop further from the path. Partial replacement of this assemblage by hornblende (and of orthopyroxene by cummingtonite) is thought to have occurred during Taconian metamorphism. The assemblage has not been found in any rocks of post-Grenville age.
Next, proceed southeastwards through the bush looking for outcrops. When you reach the north-south trail marked with yellow dots, follow it southwards to the crest of the scarp overlooking Lake Windwing. En route you will see a good section through the metawackes, pelites, hornblende amphibolites and cummingtonite amphibolites of the ZEnw member of the "Ned Mountain Formation".

Station 1C. Wacke Member of the "Ned Mountain Formation"
As you walk, you will first pass outcrops of coarse-grained K-feldspar-plagioclase-sillimanite-garnet-biotite-quartz±graphite schist of the Basal Member. The rocks ara garnet-rich and contain prominent sillimanite trains; the contrast between the sillimanite-biotite-garnet and feldspathic segregations produces a pin-striped appearance. Metawackes of the Wacke Member, slightly higher in the section, have a similar pin-striped appearance but contain more quartz and less K-feldspar than the Basal Member.
A number of medium-grained granofelsic layers are present along the trail. These range from about 10 to 60 cm thick, and contain quartz-plagioclasebiotite-garnet±K-feldspar. Fine layering is often visible on close inspection.
Near the scarp several amphibolites are interlayered with the metawackes and granofelses. These include slightly greyish hornblende-cummingtonite-orthopyroxene bearing amphibolites and blacker orthopyroxene-free hornblende amphibolites.
The thick "pinstriped" metawackes, thin granofelses and hornblende amphibolites of the "Ned Mountain Formation" Wacke Member at this locality make it strongly resemble the Manhattan Schist. But in addition to the distinctive stratigraphic position of the "Ned Mountain", it can be distinguished from the Manhattan in several ways: a) while granofelses of the Manhattan contain little or no K-feldspar, those in the "Ned Mountain" in some places have substantial amounts; b) the Wacke Member is locally graphitic near its base, while the Manhattan contains no graphite; c) cummingtonite-bearing amphibolites have not yet been found in the Manhattan Schist; and d) bedding of the granofelsic layers in the Wacke Member thins towards the north, while no geographical variation is apparent in Manhattan Schist. At this locality, granofelses in the Wacke Member have similar thicknesses to those in Manhattan Schist, mostly between 5 cm and 1 meter. But about three kilometers to the north, granofels and hornblende-orthopyroxene amphibolite beds are both typically 1.5 cm to 8 cm thick, and 4.5 km to the north, many beds are ∼1 cm thick. This thinning is interpreted to reflect a southerly provenance for the sediments of the Wacke Member (Figs. 4 and 5).
Getting down the scarp is somewhat tricky. Good exposures of migmatized metawackes of ZEnw are present in the cliffs below, but for safety, it is better to follow the trail along the crest until it turns down. From the bottom of the slope, go to the spillway of Lake Windwing (at the lake's eastern end).

Station 1D. Calc-silicates, Arkosic Sandstones, and Pelite of the "Ned Mountain Formation, ZEnc member
K-feldspar-rich quartzite and clinopyroxene-K-feldspar bearing calc-silicate are interbedded on the south side of the spillway. Beds range from 5 to 50 cm thick. A biotite-rich pelite is present on either side of the spillway. This outcrop displays the thin northern variant of the Calc-silicate Member, which overlies the Wacke Member of the "Ned Mountain Formation". Shearing and pegmatite intrusion thought to be of Carboniferous age has resulted in local development of muscovite in the pelites and tremolite in the calc-silicate.

Station 1E. Inwood Marble
The Inwood here consists of well-bedded, white and buff weathering calcitic marble. The outcrop at the lakeside contains a bed of clean quartzite. Buff-weathering marbles contain the assemblage calcite-forsterite-dolomitephlogopite±periclase whereas white marbles contain calcite-dolomitephlogopite±periclase. Although quite rich in calcite, these are magnesian marbles typical of the Inwood.
The Inwood contains more carbonate and less silica and K2O than does the Calc-Silicate Member. It is also much less diverse lithologically. Marbles of the Calc-silicate Member of "Ned Mountain Formation" and Inwood Marble can be distinguished by their mineral assemblages (Fig. 3). Forsterite and phlogopite (occasionally spinel), ±clinopyroxene are typical constituents of the more magnesian, originally dolomitic Inwood. Clinopyroxene and K-feldspar are characteristic of both the low-magnesium Calc-silicate Member and Walloomsac marble.

STOP 2. OUTCROPS OF WALLOOMSAC SCHIST AND MARBLE
Here (Fig. 6) we see Walloomsac marble that was unconformably laid down over the Inwood (Table 1). Small outcrops of Walloomsac marble lie on either side of the road. These consist of well-bedded, rusty-stained, graphitic marble; they contain calcite-quartz-plagiaclase-K-feldspar-clinopyroxene ±phlogopite. Some coarse, late tremolite is present. Walloomsac marbles somewhat resemble calc-silicate rocks of the "Ned Mountain Formation", but differ from "Ned Mountain" in their distinctive rusty staining and in the abundance of graphite.
A few meters south on the west side of the road is a small outcrop of Walloomsac Schist. The Walloomsac here consists of a rusty-weathering, graphitic, quartz-plagioclase-biotite-garnet schistose granofels. K-feldspar-rich granafelses, typical of the Calc-silicate Member of the "Ned Mountain Formation", are never found in the Walloomsac.

STOP 3. CORDIERITE-BEARING WALLOOMSAC SCHIST
Slabby-breaking, rusty-staining, quartz-plagioclase-garnet-K-feldspar-sillimanite-cordierite graphitic schistose gneiss of the Walloomsac Schist outcrops here. More pelitic than at previous stop, the Walloomsac contains cordierite-sillimanite-garnet assemblages overprinted by K-feldspar-sillimanite-biotite. In thin section, garnets are rimmed by sillimanite against cordierite. The cordierites are rust-stained and obviously relict.

STOP 4. HARTLAND FORMATION AMPHIBOLITE AND GRANOFELS
Between Stop 3 and here, you have crossed Cameron's Line, the boundary between the rocks of the Manhattan Prong and the Hartland terrane (Fig. 2). Manhattan Schist, which elsewhere structurally overlies the Walloomsac, was cut out along this part of Cameron's Line. The Hartland was emplaced over the rocks of the Manhattan Prong early in the Taconian orogeny, and was later deformed along with them. At this outcrop, quartz-plagioclase-biotite granofels of the Hartland Formation is interlayered with hornblende-orthopyroxene±clinopyroxene amphibolite. Bedding ranges from 5 cm to 50 cm in thickness. The Hartland is distinguished from the Manhattan by its abundant amphibolites, its non-rusty, relatively garnet-poor granofelses, and its rhythmically interbedded schist and granofels sequences (meta-turbidites) not seen here.
A granite showing graphic intergrowth of quartz and K-feldspar and large books of biotite is also present at this outcrop. It contains no primary muscovite and is undeformed. It is thought to be late Taconian in age.
This completes a section from the Fordham Gneiss to the structurally highest rocks in the northern Peach Lake quadrangle. Next, we will examine a section in the southern part of the quadrangle.

STOP 5. CALC-SILICATE MEMBER OF THE "NED MOUNTAIN FORMATION", SOUTHERN SECTION
These outcrops are on private property. If you come by yourself, ask permission from the owners before looking. Outcrops are located at the end of the road and on the road's north side, by the driveway going north up the hill. Beware of poison ivy.
Inwood Marble lies in the bottom of the valley you have just driven across (Fig. 7). You are on the east limb of an F2 antiform, and will continue going down stratigraphically as you proceed west. Here in the southern portion of the Peach Lake quadrangle (Fig. 1), the Calc-silicate Member of the "Ned Mountain Formation" is much thicker than at Lake Windwing. At this locality, white-and-green clinopyroxene-bearing calc-silicates and marbles are interlayered with greyish, laminated, quartz-K-feldspar-plagioclase-biotite granofelses and hornblende amphibolites. Retrogressive tremolite and epidote is locally present in calc-silicate layers. The characteristic ribbing on the weathered surface of the calc-silicates reflects variations in bed-by-bed carbonate content. Some granofelsic layers are clinopyroxene-hornblende-bearing, but rich in K-feldspar whereas others are plagioclase-and biotite-rich. Modal K-feldspar in the granofelses varies from 20% to 70%, while quartz ranges up to about 60%. The granofelses show a faintly developed linear fabric.
Dikes of a Taconian granite lie in an axial-planar attitude to F2 folds. This granite is heterogeneously deformed; some parts show little foliation while others show a strong shear fabric. Small xenocrysts of calc-silicate and blebs of pyrrhotite are present in the granite. Although the granofelses (and related beds of granitic gneiss) and Taconian granites overlap compositionally, they can be distinguished by the following criteria: a) granofelses are essentially concordant, Taconian granites discordant; b) fabric tends to be homogeneously developed within the granofelses, heterogeneously in Taconian granites; c) K-feldspar rich granofelses do not generally contain sulfide, while Taconian granites can contain several percent. Layers of K-feldspar rich granofels, typically 2 to 10 cm thick, are scattered throughout the Calcsilicate Member in the south. Such layers have not been seen in the Inwood or Walloomsac marbles.

STOP 6. VOLCANICLASTIC MEMBER, "NED MOUNTAIN FORMATION"
K-feldspar-plagioclase-quartz granofelses of the Volcaniclastic Member (Fig. 7) outcrop to the east of the parking space; hornblende amphibolites outcrop to the west.
The Calc-silicate Member of the "Ned Mountain Formation" overlies and grades down into the Volcaniclastic Member in the southern Peach Lake quadrangle (Figs. 4 & 5). The Wacke Member is absent in the south: sediments here appear to have been largely volcaniclastic in origin. The granofelses in this outcrop are highly feldspathic, and include probable meta-tuff beds in the eastern end of the outcrop. Granofelses at the eastern end show thin (2 mm to 10 cm) layering, and generally contain little biotite. Occasional greenish clinopyroxene-bearing calc-silicate layers occur. Porphyroclasts and larger calc-silicate nodules containing plagioclase-quartz-clinopyroxene-hornblende are scattered through the granofelses. Some beds are relatively rich in biotite and quartz. A layer of amphibolite is present in the central portion of the outcrop; boundinaged amphibolites lie within the granofelses at the western end. These amphibolite layers appear to be related to the hornblende-clinopyroxene calc-silicate nodules and are probably of calc-silicate origin. The Volcaniclastic Member here clearly shows affinities to the granofelses of the Calc-silicate Member seen at Stop 5. Amphibolite within the Volcaniclastic Member at Pound Ridge (Figs. 2 & 4) also contains hornblende-clinopyroxene, but these minerals are restricted to amphibolitic layers there.
The hornblende amphibolite of the outcrop west of the pullout is fairly homogeneous. This amphibolite is about 15 m thick; it probably represents a metamorphosed basalt flow, but its origin remains uncertain. A Taconian granite at the west end of this outcrop has resulted in alteration to biotite.

STOP 7. CALC-SILICATE MEMBER, "NED MOUNTAIN FORMATION"
You have just passed the hinge surface of the F2 Taconian antiform. A D2 shear zone truncates the stratigraphy on the west side of the fold (Fig. 7). The Volcaniclastic Member is missing here, although it is present further north. At this location, one can see the repeat of the Calc-silicate Member on the west limb. Inwood Marble lies in the valley to the west.
On the west side of the road, near its intersection with Pettit Road, is an outcrop of white-and-green calc-silicate. The weathered surface of the outcrop shows the ribbed appearance typical of this unit. A highly sheared layer of "granitic gneiss" is present. It appears to be conformable and is tentatively interpreted as a rhyolitic ash bed.
At the end of the road are outcrops of fine-grained, purplish and grey quartz-K-feldspar-garnet-biotite±plagioclase granofelses and somewhat rusty, K-feldspar-rich metasaprolites. Metasaprolite is notable in outcrop for the abundant K-feldspar grains (1 cm to 5 cm in diameter) evident on the weathered surface. Biotite, sillimanite, and garnet are also present, but quartz (primarily in veins) is only ∼10% of the rock. The granofelses, present along side the metasaprolite, are quite different; quartz consists of 50%-80% of these rocks.
Although hard to see in outcrop, a cross-cutting foliation locally truncates the bedding. Thin section examination of the granofels reveals a highly sheared fabric defined by quartz ribbons. Here grain size in both the granofels and especially in the metasaprolite is unusually fine due to intense shearing. This shearing may be related to the D2 shear zone to the east.

STOP 8. MANHATTAN SCHIST
Turn right into parking lot opposite a church and beside the Lewisboro Police building. Intersection with Route 35 is in sight just ahead. From this parking lot we will walk to Stop 8, which is located at the east end of the roadcut on the south side of Route 35.
Route 35 is a narrow 2-lane highway with cars and trucks traveling fast in both directions. They do not have time or space to avoid errant pedestrians who pop out unexpectedly from the bushes! Because of this, it is safer to follow a route through the woods to reach the part of the roadcut where the Manhattan Schist is best exposed. (Most of rock exposed in the road cut is Taconian granite.)
Walk to the intersection of Spring Street with Route 35 and cross to the south side of Route 35. Walk east for -30 m to the sign for Route 35, then cut up through the bushes onto the bench above the highway. [The bench is covered by open woodland with no underbrush and is easier walking than the roadside.] Follow the top of the roadcut east for -300 meters, until the ground starts to drop off, and the roadcut is clearly decreasing in height. Climb down to road level. Be careful; a small stream lies between the roadcut and the road. There is little room to maneuver here.
Between Stop 7 and this outcrop, you have passed over Inwood Marble and Walloomsac Schist (Fig. 2). An outcrop of graphitic Walloomsac granofelses lies about 700 m east of Stop 8 on Route 35. At Stop 8, the structurally highest rocks in the southern Peach Lake quadrangle are exposed.
Interlayered amphibolite and quartz-plagioclase-biotite-garnet granofels of the Manhattan Schist are present at the eastern end of the outcrop. A dark, sooty stain (from the highway?) is present on many of the rocks. Some F1 isoclinal folding is visible in part of the amphibolite. Granofels beds vary from less than 1 cm to over 45 cm thick; a granofels-rich section extends for about 1.5 m. Proceeding westwards, the blocky granofels and amphibolites are followed by highly weathered metawackes. These rocks contain dark-colored biotite-garnet-sillimanite segregations and light-colored quartz-plagioclase veins and segregations. In thin section, biotite is brown, unlike the reddish biotite typical of the Walloomsac. As discussed at Stop lC, the Manhattan strongly resembles the Wacke Member of the "Ned Mountain Formation", but occupies a very different structural position.

A2: THE GREEN POND OUTLIER OF NEW YORK AND NEW JERSEY; A MESOSTRUCTURAL LABORATORY
JAMES P. MITCHELL
The Pennington School, Pennington, NJ 08534
RANDALL D. FORSYTHE
Department of Geography and Earth Science, UNCC, Charlotte, NC 28227
Exposures of the folded Silurian and Devonian strata of the Green Pond outlier within the Reading Prong of New Jersey and New York (Fig. 1a.) contain abundant small scale deformation features. These include: slickenfiber faults, en echelon vein arrays, two sets of disjunctive cleavage, and small scale folds. This trip visits a series of outcrops within the outlier that permit a detailed study of the interrelationships and origin of these mesostructures.
Students of structural geology are commonly introduced to small scale (meso) structures classed as being either brittle or ductile. In the Earth, however, brittle deformation is not necessarily restricted to the upper "seismogenic" layer, and ductile deformation likewise is not restricted to the deeper medium to high grade metamorphic levels. Folds that form under moderate confining pressure and low temperatures, often reveal a confusing array of both ductile and brittle mesostructures. The manner in which these ductile and brittle features are related is one of the interesting topics that can be examined on this trip.
The trip also provides students an opportunity to understand some of the dynamic or stress conditions that operate during folding. Published work on folded strata (for discussion see Ramsay, 1967) has generally focussed on the geometric development of folds and its strain-related cleavages or foliations. The array of semi-brittle features that formed along with the cleavage in the Green Pond outlier permits an appreciation of the forces or stresses responsible for folding.

A2: THE GREEN POND OUTLIER OF NEW YORK AND NEW JERSEY; A MESOSTRUCTURAL LABORATORY

STOP 1. MESOSTRUCTURES IN THE UPPER GREEN POND CONGLOMERATE
The Green Pond Conglomerate forms the distant cliffs which probably lie unconformably on the Middle Proterozoic rocks beneath the lake. This is the eastern margin of the Green Pond outlier. Bedding dips northwest beneath the mountain. You are also located at the transition between the northern portion of the outlier defined by one large syncline and the central portion defined by three smaller wavelength anticline /syncline pairs. Superimposed on this NW dipping limb are two smaller anticline/syncline pairs that can be seen in this roadcut.
The purpose of this stop is to examine associations of the en echelon vein arrays, slickenfiber faults, and cleavage and to relate them to the paleostress directions and progressive folding.
Walk along the west bound lane about 100 m to the north face of the exposure. Beginning at the east end of the outcrop, walk about lO m until you see quartz veins at eye level.
a. En Echelon Vein Arrays. Several subhorizontal arrays of quartz veins occur in 'en echelon' arrangement (Fig. 11). Each array forms within a tabular shear zone and contains veins with a geometry that clearly indicates the sense of shear. In this case the top block moved westward (to the left). These features called en echelon vein arrays (EVA) have also been called tension gash arrays.
EVA Paleostress: The array and vein attitudes indicate (assuming type 1 geometry, see Figure 3b) that bedding parallel compression caused these particular EVA's to form. The direction of maximum compression that forms an EVA parallels the direction of greatest shortening which lies somewhere in the acute angle between the shear zone (array attitude) and a vein member (Fig.11).
Walk 30-40 m to the small Geodetic Survey sign located above a Bench Mark. See Figure 10 for location.
b. Slickenfiber Faults. Examine the many minor faults (Fig. 12) with lineations defined by mineral fibers, called slickenfiber faults (SFF 's terminology of Wise, et al., 1985). Profiles of these features show overlapping fibers and give a sense of displacement characteristic of SFF's . Note that the quartz filled pull apart structures along some of of the SFF's give a reverse sense of displacement. The "rough-smooth" method (Durney and Ramsay, 1973) also indicates reverse displacement. The exposed footwall surface feels smooth to the hand when rubbed upwards along the surface, therefore the hanging wall moved up defining a reverse motion. The rough-smooth technique is reliable for SFF's because fibers always lie in plates that are overlapped in one direction like the shingles on a roof.
SSF Paleostress: Most SFF surfaces here developed on crossbedding surfaces dipping more steeply to the northwest than the bedding. Thus bedding parallel compression indicated by the EVA's, may also represent a conjugate shear system with SFF's following steep planes of weakness in the rocks (crossbeds oriented suitably for slip in the given stress field) and EVA's forming subhorizontal shears across rock anisotropies and in more massive rocks.
Walk 7 m west of the Bench Mark. See Figure 10 for location.
c. Conjugate EVA's and SFF's. As sketched in Figure 13, conjugate SFF's and EVA's occur in concert. A subhorizontal SFF overprints an EVA with the same sense of displacement (top block westward) . This is conjugate to a steeply dipping bedding plane-SFF with veins whose displacement is top block upward to the east. These displacements are opposite but complementary such that the principal axes of shortening and compression bisects the two shears and is at a low angle to bedding. Lying in the intersection of the two shears is a quartz vein which is subparallel to the compression direction. This vein is common in conjugate EVA's and is a reliable indicator of paleostress directions.
Progressive Strain: Note the subhorizontal EVA veins in Figure 13 are sigmoidally shaped indicating progressive shear whereas, the steep EVA veins are straight, dilated, and incompletely filled with large quartz crystals (comb structure). This conjugate association can be seen in other places and may represent a slight rotation of the principal axis of compression towards the sigmoidally deformed EVA's (Fig.14). Such a rotation of the stress field, following the initial development of conjugate EVA, would substantially dilate one set of veins. This set will have straight tips which propagate at high angles to their array (synrotational EVA's of Fig. 8). The other set of veins will have curved tips that propagate at low angles to the array (antirotational EVA's of Fig. 8) .
Walk about 34 m to a position where purple rocks project slightly closer to the curb. See Figure 10 for location.
d. EVA and SFF Links. Again, SFF's occur on steep crossbeds, but this time several SFF's at eye level link up with EVA's higher in the outcrop to form a continuous shear zone with a mutual reverse sense of displacement (Figure 15). Furthermore, the same EVA's are paired with subhorizontal EVA's of the conjugate orientation. This is an outstanding association that clearly indicates the complimentary association of SFF's and EVA's in this area, and the conclusion that many of these features formed in response to maximum compression directed subparallel to bedding.
Importance of microcracking: What controls whether a shear zone will develop into a SSF or EVA? Certainly planes of weakness in the rock favor SFF development, but sometimes SFF's cut across rock anisotropies. We postulate that the microcracking distribution prior to rock failure determines the thickness of the shear zone and therefore whether SFF's or EVA's will develop (Fig. 16). For example, the linked SFF and EVA shear zones at this site may reflect an incipient zone of microcracking that was narrow at the base where the SFF end developed and wider at the EVA end.
Walk about 30 m to a southeast dipping limb and the core of an anticline. See Figure 10 for location.
e. Mesostructures Record Progressive Folding History. Beginning here two anticlines and synclines can be viewed in four sections (the median exposes two sections). Veining here is profuse and complicated. Some EVA's in the hinge zone are bent or curved with pronounced sigmoidal shapes. These veins are interpreted to have been formed early and then incrementally deformed during folding. In the median exposure (facing the west bound lane), there is a complex set of crosscutting veins that reflects rotation of the veins with respect to stresses during buckling. A late vein found here is suggestive of a late subhorizontal compression subnormal to a steep cleavage in an adjacent bed. Also in the cleaved bed (purple bed at the end of the median), is a conjugate EVA with compression bisecting the obtuse angle. Dissolution of veins at cleavage selvages confirms that this conjugate EVA was later shortened during cleavage development. Also, the veins of the subhorizontal EVA are sigmoidally deformed while the veins of the steep EVA are comparatively straight and dilated (as at site c.). This suggests that the principal stress field rotated away from bedding parallel compression as folding progressed (model shown in Fig. 8). This deformed zone may be very near the fault tip of a buried northwest-dipping reverse fault. It also parallels a steep northwest dipping reverse fault exposed about 100 m to the northwest in the median. In addition to the fault, two anticline-syncline pairs can be seen from both traffic lanes when walking northwestward along the median.

STOP 2. MESOSTRUCTURES !N THE BELLVALE SANDSTONE
The Bellvale Sandstone floors the road shoulder. Bedding dips NNW towards the axis of the major syncline that extends northeastward into New York State. You are at a position on the fold near the hinge where bedding begins to wrap around the nose of the plunging syncline. The purposes of this stop are to examine EVA's, cleavage and their geometric relations.
Cleavages: A pronounced spaced cleavage strikes about N 80 E subparallel to bedding and a faint cleavage strikes about N 60 E subparallel to the fold axis (time permitting, cleavages and bedding attitudes are more clear at the spillway bridge on Clinton Road, northern stream bank).
En Echelon Vein Arrays: A large EVA seen here indicates N-S shortening and compression (using the vein/array bisectrix rule for type 1 geometry). This stress field is roughly normal to the spaced cleavages and is postulated to represent a second discrete non-coaxial phase of deformation in the Green Pond outlier. Also note the occasional occurrence of unusually long vein tips extending beyond the EVA shear zone (Fig. 17). These veins when propagating out of the shear zone commonly curve into parallelism with the bisectrix of the vein and its array. This is the direction of the inferred maximum compression. If microcracks in the shear zone in part control vein attitudes then veins that propagate faster than others breakout of the array and may be free of the internal constraints that control intra-EVA crack tips. Thus the breakout veins are probably reasonably good indicators of the paleostress field.
Slickenfiber Faults: SSF offset some veins, most with apparent left lateral displacements. However, some of these have fibers that actually indicate dip-slip motions on NW dipping surfaces.

STOP 3. MESOSTRUCTURES IN THE LOWER skunnemunk CONGLOMERATE
You are in the same syncline as that present at Stop 2 but on the opposite limb. Beds of the lower Skunnemunk dip steeply SE towards the syncline axis. Rocks vary in color (gray, red, purple) and lithology (conglomerate, sandstone, muddy siltstone), typical of the Bellvale-Skunnemunk gradational contact. The main purposes of this stop are to: 1) see two cleavages, and 2) see unusually large EVA's that record hinge parallel compression.
Cleavage: Two spaced cleavages are visible in some of these rocks. One strikes northeastward subparallel to bedding and the fold axis, the other strikes N 85 E. They have the same general strikes as the two cleavages at Stop 2 suggesting two distinct periods of shortening.
En Echelon Vein Arrays: EVA's record a variety of paleostress directions at this site. Figure 10 shows EVA data compiled from Stops 3 and 4 (SE dipping limb only). Some EVA's on this limb of the fold record NW trending (steeply plunging) layer-parallel compression, but other indicate compression at high angles to bedding. These likely record early and late stages, respectively, of a progressive folding history.
Some EVA's in this area record more northerly directed compression. These directions are approximately normal to the N 85 E cleavage.
Unusually large EVA's record NE-SW trending compression directed subparallel to the fold axis. They contain large gently dipping veins often dilated and incompletely filled. Veins are typically one meter long, one meter wide, and spaced up to two meters apart. They likely formed late in the folding history once the fold axis was well defined. They may be an anisotropic response to the N-S directed shortening by other EVA and compatible with the N 85 E cleavage.
Slickenfiber Faults: Most SFF's are bedding plane and cross bedding slip surfaces that record NW trending displacements that are compatible with major folding and NE trending cleavage development.

STOP 4a. MESOSTRUCTURES IN THE UPPER SKUNNEMUNK CONGLOMERATE
You are located on the same SE dipping limb as at Stop 3, but in this case we are hiking up the hill to the east (up section) into the axis of the syncline. The purposes are to observe numerous SFF's, EVA's, and a distinct N 85 E cross cleavage. Lock the vehicles, and hike eastward up the mountain along the right side of the pipe line clearing. Although the hike is perhaps strenuous to some, the geology and scenery (at Terrace Pond) makes this a worthwhile endeavor.
As you work your way up the ridge keep an eye out for the trail head of the Blue Dot Trail that will take us to Terrace Pond (0.3 miles up the gas line clearing). Before heading in, however, there are exposures under foot in the pipe line clearing near the trail head worth a bit of investigation.
Slickenfiber faults: The outcrops under foot in the pipe line clearing contain exposures of conjugate SFF's. Also, along the forest edge opposite the entrance to the trail is a slip surface worthy of close examination. Here, the SFF surface has two directions of fibers. Upon inspection you should be able to discern their relative timing. A N-S oriented set of fibers has been superimposed over a NW-SE oriented set, and suggests a clockwise shift in the axis of maximum compression.
En echelon vein arrays: The EVA's here largely record NW-SE trending shortening compatible with folding and most SFF's.

STOP 4b. Terrace Pond.
Now proceed into the woods on the Blue Dot Trail to Terrace Pond (0. 4 miles). Along the way are a discontinuous series of exposures within which various mesostructures can be examined.
Cleavages: A distinctive spaced cleavage occurs throughout this area that trends obliquely to the fold axis at about N 80 E. It crosses both limbs and can be seen on both sides of the pond (see Figure 18 for cleavage and bedding) The far cliff descending into the pond is the opposite limb of the syncline (bedding: N 35 E, 75 NW). You are standing on the western limb that forms the west margin of the pond (bedding: N 22 E, 30 SE) . The fold axis is submerged. Many mesostructures can be seen along the White Dot Trail that circles the pond. For example, on the west margin an excellent pair of intersecting conjugate EVA's record a near N-S trending compression compatible with cleavage formation in the same rocks (see Fig. 19).
Field Exercise for Students. This location is an excellent choice for conducting a field-base lab in mesostructural analysis. Structure students can be taught how to recognize, measure, and interpret SFF's and EVA's along the trail on the way in to Terrace Pond. Then, working around the pond on the White Dot Trail they can collect their own data, first on the west limb, and then on the east limb. The data can be plotted later on stereonets and used for making an interpretation of the paleostress history in the area. Sample data spreadsheets, and a crib sheet for measuring EVA's are shown in Figure 20. The scenery and wilderness setting certainly adds a sense of spirit and adventure to what might otherwise be thought of as a rather tedious exercise.

A3: STRUCTURE AND PETROLOGY OF THE PRECAMBRIAN ALLOCHTHON AND PALEOZOIC SEDIMENTS OF THE MONROE AREA, NEW YORK
The area covered by this trip lies in the northern part of the Monroe 7 1/2′ quadrangle, New York, and consists of a folded and faulted complex of autochthonous Precambrian gneisses, Lower Cambrian through Middle Devonian sediments and allochthonous Precambrian gneisses. Geologic maps covering the trip area have been published by Ries (1897), Fisher, et.al. (1961), and Jaffe and Jaffe (1962). Unpublished maps prepared by Colony and by Kothe (Ph.D. thesis, Cornell Univ.) undoubtedly contain valuable information but are not available for study. Recent workers in adjacent areas include Dodd (1965), Helenek (in progress) and Frimpter (in progress), all in the Precambrian autochthon, and Boucot (1959) and Southard (1960) in the stratigraphy and paleontology of the Paleozoic sediments. The work of Colony (1933), largely unpublished, is impressive.
This article is reproduced (with minor editorial changes) from the New York State Geological Association Guidebooks of 1962 and 1967. The log has been modified to reflect road changes in the last 22 years.
HOWARD W. JAFFE, University of Massachusetts
ELIZABETH B. JAFFE, Amherst, Massachusetts

A3: STRUCTURE AND PETROLOGY OF THE PRECAMBRIAN ALLOCHTHON AND PALEOZOIC SEDIMENTS OF THE MONROE AREA, NEW YORK

STOP 1. ORECO TERRACE: BELLVALE GRAYWACKE
The outcrop is on the right side of Oreco Terrace just above the intersection of N.Y.208, Orange and Rockland Road, and Oreco Terrace. Here, the Bellvale graywacke of the Hamilton Group (Middle Devonian) is exposed in a section approximately 220 feet thick. It consists of 20 - 40 foot beds of dark blue-gray, green-gray, or gray, fine-to medium-grained (0.08 - 0.25mm average grain size) lithic arenite or graywacke, rhythmically interbedded with thin beds of dark green-gray to blue-gray shale. A representative modal composition of the graywacke follows:
Mode Of Bellvale Graywacke
Detritals: | |
| quartz | 20%
| oligoclase | 2
| shale phyllite | 44?
| siltstone chert | 15
| greenstone | 1
Matrix: | |
| clay, sericite, chlorite, Mn oxide | 15?
Metamorphic: | |
| chlorite | 2
| muscovite | 1
| | 100%
Texturally, the rock consists of angular, elongated slivers of detrital quartz and predominantly phyllitic rock fragments (0.08 - 0.25mm) set in a fine matrix of sericitic muscovite, clay, and chlorite. It is often difficult to distinguish smeared-out phyllitic fragments from balled-up micaceous matrix, both of which frequently blend or flow together. Depending upon the uncertainty of the matrix content, or the classification used, the Bellvale is either a low-rank graywacke (Krynine, 1948), a subgraywacke or a lithic graywacke (Pettijohn, 1957) or a graywacke (Folk, 1954). Larger bent grains of chlorite and muscovite in the matrix, are here interpreted to have grown from fine matrix material marking the beginning of the chlorite zone - greenschist facies of regional metamorphism imprinted during the Appalachian orogeny.
In general, the Bellvale graywackes tend to show rhythmic interbedding with shale, with graded bedding low in the section and strong current crossbedding higher in the section. Occasional brachiopods are found low in the section; plant fossils are found higher up. Both features suggest gradation from marine to non-marine depositional environment. The provenance was a low-rank metamorphic or sedimentary terrane.
The shattered outcrop at Oreco Terrace is at the southwest corner of Rotated Block 8 (Fig. 2) and lies near the intersection of four directions of faulting. Attitudes of prominent structures at the outcrop are tabulated:
| STRIKE | DIP
Bedding, Cgl., North end of hill | N 8 E | 77E
Bedding, Cgl., North center of hill | N 59 W | 70NE
Bedding, Cgl., Center of hill | N 27 W | 50NE
Cross-fault | N 77 W | 90
Bedding, Qtz., South end of hill | N 2 W | 60E

STOP 2. GOLF RANGE: SHAWANGUNK CONGLOMERATE
The Shawangunk conglomerate and quartzite (Greenpond conglomerate unit) of Lower to Middle Silurian age occurs in a series of small outcrops extending northeastward along the western edge of skunnemunk Mountain syncline. At this stop the Shawangunk forms a small, relatively inconspicuous topographic knob as contrasted with its occurrence near Stop 5, where the same unit forms the spine of the steep, southeast-facing escarpment of Lazy Hill. At the present stop the Shawangunk consists of about 75% buff pebble conglomerate intercalated with 25% fine-grained green-gray quartzite.
The conglomerate consists of white pebbles of milky vein quartz (averaging 15 - 40mm in length) in a matrix of finer pebbles and grains of rounded quartz, all cemented by secondary silica and buff-orange-red ferric oxides. Occasional pebbles of white orthoclase are present as are black pebbles consisting of green tourmaline and quartz. The color of the weathered surface of the outcrop varies from pink (hematite) to yellow-brown (goethite) or black (manganese oxide dendrites) with some green contributed by lichens.
The pebbles, obviously well-rounded when deposited on the Late Ordovician erosion surface, have taken on a secondary angularity and elongation due to stretching, crowding, rotation, and slippage in the bedding planes produced during Paleozoic orogenies. Most of the pebbles show maximum elongation parallel to the fold axis (b-fabric axis). Many of the pebbles have been corrugated and a large number are cracked and sliced parallel to the b-c fabric plane. Bedding surfaces are slickensided, fluted, and warped parallel to the a-axis (down-dip). The fine-grained, gray-green interbedded quartzite is composed of quartz and minor orthoclase cemented by authigenic quartz, muscovite and chlorite, and Fe-oxides.
The elongation and shattering of the pebbles here at Lazy Hill to the south-west greatly exceeds that observed in pebble beds in Lower and Middle Devonian rocks (Connelly conglomerate of Oriskany age, and Bellvale graywacke, respectively) in this area, suggesting that the Shawangunk was involved in an additional deformation episode of possible pre-Oriskany age.
A pre-Acadian, Silurian deformation period in New York was reported by Megathlin (1939) and discussed by Kay (1942). The sporadic outcrops of Shawangunk quartzite to the north along the western limb of the skunnemunk Mountain syncline are all heavily silicified and sheared, again much more so than quartzites of Oriskany and Bellvale age.
The conglomerate and quartzite outcrop is S-shaped, with the attitudes of the bedding and a cross-fault as follows:
| STRIKE | DIP
Bedding, Cgl., North end of hill | N 8 E | 77E
Bedding, Cgl., North center of hill | N 59 W | 70NE
Bedding, Cgl., Center of hill | N 27 W | 50NE
Cross-fault | N 77 W | 90
Bedding, Qtz., South end of hill | N 2 W | 60E
The cross-fault displaces the stratigraphically higher Shawangunk quartzite member to the west, putting it on strike with the lower conglomerate member of the Shawangunk Formation. On first viewing the outcrop, the alternating pebble beds and fine feldspathic quartzites lead one to suspect that the beds are overturned. On close inspection this does not appear to be the case.

STOP 3. MUSEUM VILLAGE KLIPPE: ALLOCHTHONOUS PRECAMBRIAN LEUCOGNEISS RESTING ON CAMBRO-ORDOVICIAN WAPPINGER DOLOMITE
From the Old Mansion Road cut in the Precambrian Museum Village klippe, look south across the N 75°W-trending Quickway crossfault. The ridge due south is the Bellvale synclinal extension of skunnemunk Mountain. The next ridge to the west is Lazy Hill, held up by Shawangunk conglomerate, and offset from the Golf Range Shawangunk conglomerate of Stop 2. To the west of Lazy Hill, the next prominent ridge is the Goose Pond Precambrian klippe, formerly continuous with the Museum Village klippe and now offset about 2 miles along the Quickway cross fault.
Museum Village klippe is a thin, synclinal, saucer-shaped slice of gray-white albite-quartz-microperthite leucogneiss that has survived five or six orogenies. The rock of the allochthon were deposited as a clastic wedge (molasse) in a reducing environment, perhaps as long as 1500 million years ago; they were folded and metamorphosed to the sillimanite-almandine-orthoclase metamorphic grade about 1100 million years ago; thrust from the east in Taconic or Late Ordovician time; refolded and faulted in Taconic time; possibly again in Acadian time; refolded and faulted in Appalachian time; and finally shattered by Triassic block faulting and associated block rotation. In outcrop, the leucogneiss is heavily shattered and slickensided with lineations often running in three directions at a given place. Quartz grains and pebbles are stretched into thin corrugated tongues and sheets showing elongations of 15:1 and 20:1 parallel to the b- and a- fabric axes. Over most of the outcrop, biotite and garnet are extensively retrograded to chlorite, and abundant calcite veinlets cross at all angles.
Towards the central and western part of the cut there occur occasional thin layers rich in fresh biotite and uncommonly coarse laths (not needles) of fresh blue-gray sillimanite that have survived the complex orogenic history. As none of the Cambro-Ordovician or younger rocks in the area show any metamorphic grade higher than chlorite zone metamorphism, the sillimanite is assumed Precambrian in age, and its preservation in large fresh grains in an otherwise extensively retrograded outcrop is remarkable.
Modal analyses of samples collected along an east-west traverse across the Museum Village klippe follows:
| | Sample Number |
| East Side | Center | West Side
Almandine-pyrope | 0.1 | 2.0 | - | -
Tourmaline | - | + | + | -
The presence of albite in the most retrograded gneisses of this and the other allochthonous Precambrian blocks studied, fairly consistently suggests that it may be a retrograded mineral after an originally more calcic plagioclase. The K-feldspar in all of these rocks is microperthite (usually microcline microperthite) and is indicative of a temperature of Precambrian metamorphism of the order of 600°C. The presence of two plagioclases, one as free grains and the other exsolved in microcline microperthite, is characteristic of many of the granitic gneisses of both the autochthon and the allochthons. In some of the allochthonous leucogneisses, the microperthite and the albite tend to occur in separate bands which may reflect original compositional differences.
Return to the cars and cautiously descend the hill to the left to the Quickway (N.Y. 17-West/U.S. 6). Beware of high speed traffic and stay close to the outcrop which parallels the highway. Walk to the extreme west edge of the roadcut where the Precambrian leucogneiss rests in overthrust contact on the light gray Cambro-Ordovician Wappinger dolomite. Note the occasional flat-lying, slippery fracture planes of the contact.
The metamorphic layering in the allochthon dips to the east whereas the dolomite bedding dips predominantly west.
The average foliation of the leucogneiss is N33°E, 20°SE. The average attitude of the dolomite beds is N22°W, 35°W. Prominent faults in the klippe parallel the metamorphic layering and trend N22°E, 20°SE. The fault contact of the dolomite and the klippe is irregular and has the same general attitude. Both the dolomite and the klippe are cut by vertical faults trending N27°W.

STOP 4. GREEN POND MOUNTAIN: PRECAMBRIAN ALLOCHTHON OVER OVERTURNED HUDSON RIVER PELITE.
Observe black, fissile Hudson River shales (Middle? Ordovician) in the road cut at the northwest edge of the Precambrian allochthon. Careful observation will show that the attitude of the bedding and cleavage is N78°E; the bedding dips 70°S and the cleavage 40°S. This indicates that the outcrop is on the limb of an overturned fold with the synclinal axis north. The shales both here and at Bull Mine Mountain klippe to the north are all wildly folded and overturned close to the overriding Precambrian allochthons.
Many of the Hudson River black shales are calcareous, and consist of fine laminae (0.05 ~ 0.1mm) of dolomitic silt or mud (marl) intercalated rhythmically (occasionally cross-bedded) with carbonaceous shale. An estimated thin-section mode of a representative Hudson River "shale" follows:
| Mineral | Calcareous laminae | Mineral laminae
Detritals and matrix | | |
| dolomite, calcite | 30% | 5%
| plagioclase, microcline | 10 | +
| mica, clay, chlorite | 15 | 50
| carbonaceous matter, graphite | - | 15
| pyrite | - | +
Metamorphic: | | |
| chlorite, muscovite, biotite | - | 5
| | 100% | 100%
Walk about 100 - 150 feet into the woods southwest of the shale outcrop on N.Y. 17M. A moss-covered rubble of shale, dolomite, and "limonitized" fault breccia indicate where the covered contact has been crossed. The edge of the Precambrian allochthon of Goose Pond Mountain is found about 130 feet south from the road, and the first rock found in place is a graphitic calcareous quartzite of which sample No. 527 is representative.
Return to the cars and drive 0.4 mi east on N.Y. 17M, stopping at a white albite-quartz-microcline microperthite leucogneiss (sample No. 20), in places graphitic, biotitic or rarely, garnetiferous.
Note the extreme elongation and smearing out of quartz pebbles and grains similar to that seen at the Museum Village outcrop of Stop 3. Further to the east, the rocks become increasingly calcareous (sample No. 788). At the extreme eastern edge, prehnitized calc-silicate leucogneiss is interlayered with some amphibolite, the latter of probable basic volcanic origin. Modes of representative rock types of the Goose Pond allochthon follow:
Modes Of Gneisses Of The Goose Pond Mountain Allochthon
| | Sample Number |
| East Side | Center | West Side
Brown Hornblende | 0.2 | 33.0 | - | -
Here, as in the Museum Village klippe of Stop 2, the greatest amount of retrograding occurs at the eastern and western margins of the allochthon with some fresh rocks occurring near the center. If the klippen are indeed synclinal saucers the presently exposed centers of the masses would lie at a further distance from the sole of the thrust and would be expected to show less alteration. It should be emphasized that the Precambrian autochthonous gneisses in the southern part of the Monroe quadrangle (Jaffe and Jaffe, 1962) are not comparably retrograded except near Triassic border faults.

STOP 5: Shawangunk Quartzite
STOP 5. LAZY HILL - SHAWANGUNK QUARTZITE
Walk 0.2 miles west crossing buried northeast-trending fault contact between the Shawangunk ridge of Lazy Hill rising steeply ahead and the Bellvale ridge of Durland Hill to the rear. Walk to the north nose of Lazy Hill (permission of the owners, the Durlands, is necessary) where a large outcrop of Shawangunk quartzite is exposed. The rock is a thin-bedded, pink, buff and white orthoquartzite consisting of:
Mode of Shawangunk Orthoquartzite, Durland Property
Quartz | 93%
Chert | 5
Sericite, Chlorite | 2
Zircon | +
Hematite | +
Goethite | +
Pyrite | +
Green tourmaline | +
| 100%
|
The quartz grains are well-rounded, moderately elongated, well-sorted (average diameter, 0.75mm), and the rock is very tightly cemented. Each grain of quartz is cemented to another by authigenic quartz overgrown in optical continuity with the detrital cores. Undulatory extinction due to deformation passes through the core and overgrowth of each grain. The Lazy Hill ridge top to the south (not visited) is formed of a coarse white pebble conglomerate interbedded with white orthoquartzite (occasionally ripple-marked) and grades eastward to a red arkosic conglomerate below the ridge-top. Quartz pebbles and orthoclase pebbles are strongly elongated (3:1 and 4:1) and heavily shattered and veined in both the red arkosic and the white conglomerate.

STOP 6. MONROE BOWL-0-FUN: CONNELLY (ORISKANY) -ESOPUS CONTACT)
2012: Monroe Bowl-O-fun burned down in 1997.
The outcrop at Monroe Bowl-0-Fun originally was described by Jaffe and Jaffe, (1967) to consist of about 300 feet of the Esopus Formation underlain at the rear of the cut by red and white pebble conglomerate, the Connelly Conglomerate of Oriskany age. Most of the exposure has been covered by a railroad tie retaining wall. Here, a small outcrop of the Connelly is still exposed to the far right near the gasoline service station, and was described by Jaffe and Jaffe (1967) to consist weathered yellow, "limonitic" conglomerate (3 ft or more), succeeded by white to buff, pebble-bearing orthoquartzite (5 ft), which is in turn overlain by bright red hematitic quartzite (10 ft). The pebbles in the Connelly conglomerate are of white, round to slightly elongated quartz, averaging 1-2 mm in maximum dimension. The Connelly is disconformably overlain by a lowermost member of the Esopus Formation, recognized by Southard (1960). A small exposure of the Esopus Formation is exposed at the far left of the retaining wall. The attitude of both the Connelly and the Esopus at their contact was described to be N68°E, 45°N. A heavily slickensided fault surface, trending N53°, 60°SE cuts across the Connelly beds and presumably also cuts the overlying Esopus Formation.
The lowermost member of the Esopus, at its base, consists of fissile, blue-gray siltstones which weather to brown and orange on cleavage surfaces. Many of the rocks are marked with Taonurus cauda-galli on bedding planes. At this outcrop the authors have collected a remarkable fauna including a specimen of the giant trilobite, Coronura myrmecophorus, not previously reported from the Esopus Formation. According to D.W. Fisher, New York State paleontologist who identified the specimen, it has previously been reported from the Schoharie and Onondaga Formations. The specimen was donated to the N.Y. State Museum collection.
The lowermost member is also relatively rich in conulariids, none of which have yet been identified. Other fauna include the brachiopods: Leptocaelia flabellites, Schuchertella sp., Acrospirifer macrothyris as well as some chonetid and orbiculoid genera. Platystomid and loxonemid gastropods, rugose corals and a dalmanitid trilobite were also collected by the authors.
The lowermost member grades into the black, poorly fossiliferous Lower Mudstone member which in turn grades into a purple sandstone at the north end of the 350 foot exposure. The sandstone is presumably the lower part of the Highland Mills member of the Esopus Formation. The fauna of the lowermost member at the Bowl-0-Fun appears to differ significantly from that of the Highland Mills member of the Esopus Formation found at Bakertown and Highland Mills (described by Boucot, 1959). The fauna should receive some serious study by specialists before the outcrop is demolished by new construction.

STOP 7. ORANGE TURNPIKE: POUGHQUAG QUARTZITE (LOWER CAMBRIAN)
Walk 0.16 miles due west over hilltop to the edge of a cliff formed by a 10 foot section of the Poughquag Formation (Lower Cambrian). The section consists of alternating 2 inch to 2 foot thick beds of ferruginous orthoquartzite, conglomerate, and arkose, striking N75°W and dipping 8°N, overlying the vertically dipping Precambrian autochthon with marked angular unconformity. This represents original sedimentary onlap with gentle warping or folding in subsequent geologic time.
Apparently the Precambrian Monroe Massif (Block 2) was sufficiently rigid throughout the Paleozoic to prevent the deformation of the overlapping embayment of Poughquag quartzite and Wappinger dolomite. This is indicated by both the gentle warping observed and also by the relative sphericity of the quartz pebbles in various Poughquag beds.
Several of the beds are feldspathic, a feature uncommon in the Poughquag of the Poughkeepsie Quadrangle (Gordon, 1911). One such bed at the Monroe outcrop is a conglomeratic arkose which is a true high rank arkose in the sense of Krynine (1948). A remarkable textural feature of this rock is the abundance of authigenic feldspar (microcline?) which is the principal cementing medium in sample No. 466. The specimen consists of 1-2 m quartz and microcline pebbles (all very round) lying in a matrix of authigenic microcline (?) cement which is clear in appearance. Some sawtooth or hacksaw terminations on the detrital microcline cores (Edelman and Doeglas, 1931) indicate that interstratal solution has taken place after deposition, presumable in situ. The authigenic feldspar overgrowths show only weak twinning when grown around detrital cores showing strongly developed microcline twinning. A mode of such rock is as follows:
Mode Of Lower Cambrian Poughquag Conglomerate Arkose Specimen No. 466
Microcline | 47.4%
Microcline microperthite | +
Quartz | 48.6
Albite-oligoclase | +
Muscovite | +
Rutile, Anatase, Tourmaline (green + brown) | 0.5
Zircon | 0.5
Hematite  } |
} | 3.0
Mn oxides} |
The mineralogical composition of the Poughquag at Monroe leaves little doubt that it was derived from erosion of the granitic gneisses it overlies.
On the return walk to the road, stops may be made at exposures of post-Wappinger lamprophyre dikes which the authors believe to be of late Ordovician age (Jaffe and Jaffe, 1962). The authors have studied the dikes in considerable detail and would suggest a possible age of intrusion similar to that of the ultramafic intrusion of the Cortland Complex at Stony Point, New York (Ratcliffe, 1967). The Cortland Complex has been dated by Long and Kulp (1962) at 435 million years by K/A isotopic ratios obtained on biotite from the complex, a date close to the accepted Ordovician-Silurian boundary. An age of 398+17 m.y. was obtained from Ar /K ratios on the amphibole (kaersutite) phenocrysts in one of these dikes (Jaffe and Jaffe, 1973). This age may be a bit low because of argon loss during a regional Paleozoic reheating· These ages were run some years before development of more refined Ar/Ar methods now in use.
Thus, lamprophyre dikes of deep-seated (mantle-derived?) origin are not restricted to Mesozoic and Tertiary ages. They may range from Precambrian to Recent (Zartman, et al., 1967).
Stops 8, 9, 10, 11, and 12 (Fig. 3) are located in the granulite facies gneisses of the autochthonous block, here called the Monroe crystalline massif of Precambrian (Proterozoic) age. For reemphasis, we note that the gneisses of the autochthon do not show the pervasive retrograde alteration and extensive mineral stretching that characterize the rocks of the allochthon.
The prevalence of hypersthene and total absence of muscovite from folded gneisses of the Monroe crystalline massif verify that regional metamorphism took place in the granulite facies. The omnipresent coexistence of hypersthene with augite in mafic rocks; hypersthene-K-feldspar association in granitic gneisses (charnockite); sillimanite-K-feldspar assemblages in pelitic gneisses; Fe-rich cordierite-sillimanite-K-feldspar-almandine-tourmaline assemblages, also in pelitic gneisses; and copious exsolution of pigeonite in host hypersthene collectively indicate that metamorphism occurred at T = 700 - 800°C, at p = 2-4 kbars (7-14 km depth) (Jaffe and Jaffe, 1973).

STOP 8. ORANGE TURNPIKE: QUARTZ-OLIGOCLASE GNEISS
Leaving Stop 7, the Orange Turnpike turns southwest and crosses the concealed unconformable Cambrian-Precambrian contact. The quasi-horizontal Poughquag and Wappinger beds overlie vertically dipping Precambrian gneisses, permitting the delineation of a major unconformity, unfortunately not exposed in the area. Beyond the Lipalian interval, the first rock encountered is a fine-grained pink alaskite composed mainly of 1-3 mm microcline-microperthite and quartz, minor sericitized albite-oligoclase and an occasional flake of biotite. Within 100 ft to the south, the pink alaskite grades through a narrow zone of coarse biotite-microperthite-oligoclase granite and granodiorite into a medium-grained (2 mm), gray, essentially massive hypersthene quartz diorite gneiss which forms the bulk of the outcrop. It is variously called quartz oligoclase gneiss or enderbite by other workers. It contains: oligoclase 70%, quartz about 25% and hypersthene, biotite, magnetite and chlorite about 5%. In thin section, quartz is not uniformly distributed but rather forms long tongues which embay adjoining oligoclase grains; these are well twinned and antiperthitic. On top of the outcrop, observe several lenses of biotite-hornblende-hypersthene-labradorite (An55) pyribolite infolded in the quartz diorite gneiss. Foliation measured on the pyribolite is N35° to 50°E, with a dip close to 90°. Slickensided joint faces strike N24° to 65°W. About 0.3 mi south (not a scheduled stop) the quartz diorite gneiss darkens in color, the quartz content drops markedly, and the rock grades to an augite diorite gneiss interlayered with hornblende-hypersthene-andesine pyribolite. Where quartz becomes locally abundant, it embays and replaces both plagioclase and the ferromagnesian minerals.
Hypersthene-quartz-oligoclase gneiss (quartz diorite gneiss) is thus formed from the metamorphic reconstitution of pyribolite accompanied by the introduction of silica and small amounts of potash. These constituents could logically be derived from anatectic granitic liquids derived from the fractional melting of sedimentary precursors.

STOP 9. HARRIMAN HEIGHTS ROAD: CALC-SILICATE MIGMATITE
A fresh roadcut exposes a dark gray, green, and pink banded migmatite. The gray rock is a calc-silicate paragneiss composed of quartz, microcline, bytownite (An80), augite, green epidote (pistacite), dark brown sphene (titanite), zircon, apatite, and magnetite. The pink bands consist mainly of quartz and microcline or microcline microperthite. Other samples of this migmatite contain almost pure anorthite (An95). Epidote, common throughout the region in calc-silicate units, evidently formed by retrograde metamorphic alteration or exchange of Ca, Al, Si, and Fe in anorthite+augite, in a wet oxygenated environment.

STOP 10: ORANGE TURNPIKE: CAMPTONITE DIKE CUTTING HORNBLENDE GRANITE GNEISS
The outcrop on the west side of the road shows a 20-25 ft dike of lamprophyre called camptonite forming the low pavement of the outcrop. It strikes N38°W and dips 86°NE. The dike contains green hornblende phenocrysts up to 1/4 in lying in a matrix of albite laths, 0.2 x 0.4 mm, which, in turn enclose granular epidote. In these rocks, it appears that deuteric alteration of an initially more calcic (intermediate) plagioclase has resulted in the growth of albite+epidote. The camptonite contains: albite - 53.3%, hornblende - 21.5%, epidote - 12.6%, chlorite - 7.3%, and apatite+opaque+calcite+quartz+k-feldspar - 5.3%.
The country rock intruded by the dike is the hornblende granite gneiss that makes up about one-quarter of the volume of the Monroe crystalline massif and is also widespread in the other areas that constitute the Hudson Highlands. In the Monroe block, these granitic gneisses are uncommonly iron-rich and the hornblendes are ferrohastingsites with 100Fe/(Fe+Mg) = 86 that coexist with Ti-and Fe-rich biotites in which 100Fe/(Fe+Mg) = 90, ratios found in minerals at this outcrop. Here, the granite gneiss contains occasional schlieren of very biotite-rich rock.

STOP 11. EAST MOMBASHA ROAD: LEUCOPHYRE DIKE INTRUDING AMPHIBOLITE
Stop 11 shows a 16 ft thick granodiorite leucophyre dike which strikes N48°W, cross-cutting the foliation of the surrounding amphibolite which strikes 57°E and dips 20°S. Note the large wedge of amphibolite in the center of the dike and the occasional pink K-feldspar-quartz bands in the amphibolite. This dike is unique in the Monroe quadrangle, and perhaps in the Highlands. It shows sparse pink phenocrysts of oligoclase, quartz, less microcline and biotite lying in a dark gray matrix, which is again porphyritic on a microscopic scale. The second generation of microphenocrysts is made up of square to rhombic zoned potash feldspar and laths of albite-oligoclase. These lie in a very fine granophyric groundmass made up of feldspar, quartz, mica, chlorite, "limonite" and manganese oxide. The extremely fine-grained oxides form megascopic crenulated black streaks which give the dike a distinct flow layering in parts of the outcrop. A mode was not obtained because of the fine nature of the matrix. X-ray data on a powdered sample indicate that oligoclase>quartz>microcline, hence the dike is of granodioritic composition. East of the road, the dike is not found, and may be cut off by a north-south fault; if so, the dike is very old. An outcrop of the same rock was found 0.25 mi to the west cutting migmatite; it may be an extension of the same dike.

STOP 12. EAST MOMBASHA ROAD: PELITIC PARAGNEISS
This is a tightly folded, crenulated pelitic paragneiss in the sillimanite-K-feldspar zone of metamorphism. The outcrop consists of thin bands of gray biotite-microcline-labradorite-quartz gneiss intercalated with bands rich in orthoclase cryptoperthite (anorthoclase) and quartz. Abundant garnet (almandine-pyrope), Fe-rich cordierite, dark blue-green tourmaline and prismatic sillimanite are developed along the interfaces of the biotitic and alaskitic layers. Biotite is, under the microscope, intensely pleochroic from "paprika-red" to almost colorless and is undoubtedly rich in Ti as well as Fe. Sillimanite and tourmaline lie in the foliation planes with their long axes parallel to the fold axes. Cordierite, not recognized when the 1962 NYSGA Guidebook was written, is abundant in parts of the outcrop and can be recognized in some places by its characteristic blue or purplish blue color imparted to hand specimens. Under the microscope, it shows both polysynthetic twinning and sector-zoning or twinning; alteration to fibrous pinite plus the twinning make it difficult to identify and it may be mistaken for altered plagioclase; characteristic yellow, bulls-eye halos are virtually absent. Thin sections cut across foliation planes show numerous square cross-sections of sillimanite needles enclosed in cordierite. The relatively Fe-rich nature of this cordierite, 100Fe/(Fe+Mg) = 25 is useful in limiting the pressure at which the high-temperature regional metamorphism occurred; it is 2-4 kbars with water vapor present but not necessarily saturating the pore spaces. This, plus the hypersthene and sillimanite-K-feldspar parageneses fix the parameters of regional metamorphism in this part of the Hudson Highlands at T = 700 - 800°C and P = 2 - 4 kbars.

A4: THE NYACK SECTION OF THE PALISADES: FACIES, CONTACTS AND LAVA DOMES
Jeffrey C. Steiner
Dept. of Earth and Planetary Sciences
The City College of New York
New York, NY 10031
The Palisades is a large, internally layered tholeiite intrusion which is exposed for approximately fifty miles along the west side of the Hudson River (figure 1). This trip examines pigeonite and augite dolerite sites on an Upper Nyack to Valley Cottage, New York traverse (figure 2).
The data previously collected at these sites will be used to address the issue of identifying the number of magma pulses which produced these and related facies. Peripherally, the relationship of the internal layering to the pulses will also be explored.
The Palisades has widely been considered to have arisen from at least two magma pulses (Walker, 1969). These pulses were defined petrographically by Walker (1969) and may be synchronous with the First Watchung and Ladentown-Union Hill Basalts, respectively (Puffer, et al., 1982, and this volume). Recently, Shirley (1987) identified three to four poorly defined pulses, none of which were characterized petrographically. The pigeonite and augite dolerites of present interest document a pulse distinct from those identified by Shirley (1987), but petrographically similar to Walker's Pulse 1 at Haverstraw Quarry.

A4: THE NYACK SECTION OF THE PALISADES: FACIES, CONTACTS AND LAVA DOMES

STOP 1 NYACK BEACH STATE PARK - OLIVINE LAYER
The escarpment at the eastern edge of Nyack Beach State Park represents the western wall of an infilled stone quarry. On this rock face, at approximately 40 feet above the presently obscured basal contact, a subhorizontal "rotten" zone (first horizontal depression above tree line) can be observed. This zone presumably represents the last vestige of the olivine layer referred to by Walker (1969) It appears to fade northward of the present location.
A closeup view of this structure, which involves a certain risk due to the fractured nature of the rock infrastructure, reveals that the basal part of this horizon is undulose and uneven. It is marked by nodules of basalt enclosed in a weathered granular matrix. Samples of both material show that the composition of the matrix is nearly identical to the composition of early dolerite at thirty feet above the lower contact at Englewood Cliff (Steiner, in preparation). An analysis of one of the olivine bronzite nodules yield 10 percent MgO. This percentage is high for most facies of the Palisades, but substantially less than the 19 percent reported by Walker (1969) for the hyalosiderite facies.
Here, as elsewhere, it appears that cooling cracks are reasonably continuous through the rotten zone. This indicates that the rotten zone belongs to the same cooling unit as the overlying dolerite.

STOP 2 UPPER NYACK - LOWER CONTACT OF UPPER NYACK SECTION
The basal contact is well exposed along a small escarpment. Here, small, infilled cavities can be observed in the Triassic baked shales indicating that the sediments were not fully lithified at the time of intrusion, and the intrusion was relatively shallow.
A scramble up the escarpment for forty feet reveals small (3 cm) nodule-like protrusions in an otherwise uniform dolerite. These analyze to normal basalt (Steiner, in preparation). An olivine layer has yet to be discovered at this locality.
Backscatter electron imaging of the quench rock (figures 7 and 8) shows subophitic pyroxene and labradorite clusters surrounded partially by pools of interstitial glass. Titanomagnetite and minor plagioclase, sanidine, quartz, and residual glass populate the interstitial spaces (figures 7 and 8) .

STOP 3 UPPER NYACK - COARSE PIGEONITE DOLERITE
This coarse pigeonite facies is characterized by elongate (1 cm) augite laths with pigeonite cores or attached plates which runII parallel to the augite prisms (figure 3). This facies is substantially enriched in REE relative to the contact facies, and shows a slight positive Europium anomaly suggestive of plagioclase accumulation (figure 6).
Time permitting, proceed 25 yards south on Route 9W to intersect a well marked service trail which drops sharply down the east bank. Samples have been taken from approximately 30 yards down the trail to the summit of Hook Mountain. From Hook Mountain, the tabular form of the Palisades is visible against the southern skyline. At Piermont, the topography changes dramatically in apparent response to a stepwise increase in the angle of westerly dip of the Palisades. Haverstraw Quarry is visible to the north. The rolling hills of the Triassic basin are framed by the Hudson Highlands to the east.

STOP 4 VALLEY COTTAGE - COARSE AUGITE DOLERITE
The best developed porphyritic texture (figure 3) in coarse augite dolerite occurs in the landscaped outcrop at the corner of Christian Herald and Herald Court. Slabs of samples taken prior to landscaping will be shown. PLEASE DO NOT DEFACE THE PROPERTY. DO NOT VISIT WITHOUT THE PERMISSION OF THE OWNER.
The iron-enrichment of the Palisades at this stop is due to abundant titanomagnetite in the groundmass. Titanomagnetite is often dendritic, and is considered to occur as both a primary and a quench feature. There is little indication that the magnetite was emplaced secondarily via an aqueous vapor or solution. Chemically, and to a certain extent petrographically (mesostasis replaces micropegmatite) this facies appears to be equivalent to the late stage ferrodolerite, fayalite granophyre and other facies of Walker (1969), except that the iron enrichment is not accompanied by iron rich ferromagnesian minerals, such as ferroaugite or fayalite. Ferroaugite rims may occur, but the bulk clinopyroxene is clearly augite.
The REE patterns (figure 5 and 6) are consistent with the derivation of this facies from the pigeonite facies through crystal liquid fractionation.

STOP 5 VALLEY COTTAGE - WEATHERED COARSE AUGITE DOLERITE
This is one of the few localities not in someone's yard which shows weathered coarse augite dolerite. Other localities occur sporadically along Mountainview Road.

STOP 6 VALLEY COTTAGE - UPPER CONTACT RELATIONS
From the intersection of Route 303 and Lake Road, walk 20 yards north along the eastern side of Route 303 to examine the contact between diabase and sedimentary rock which dips northerly at about 45 degrees. The contact is very sharp at about 10 feet up from the sidewalk alongside the telephone pole. It is otherwise somewhat hard to observe the trend do to the tendency for the dolerite to reduce the iron in the sedimentary rock producing a black baked sandy shale.
As observed at Stop 2, the intrusive dolerite has vesiculated the sedimentary rock. At this stop the cavities are somewhat sharper and lack infilling. The baked zone buttresses the east-west trending slope which marks the position of the Palisades contact as it extends toward Rockland Lake.
The texture of the contact rocks is microporphyritic with augite microphenocrysts. Within five feet of the contact the texture is ophitic, and beginning perhaps fifteen feet south, occasional recrystallized patches of interstitial mesostasis appear (figure 9).
Proceeding South, the diabase appears to plunge beneath the sedimentary cover. About 0.5 miles north of Lake Road, the contact is rediscovered on the upper potions of the exposed slope which is inset 60 yards east of route 303. The dolerite dips roughly west at about 45 degrees underneath a veneer of backed shales. The intrusive contact is therefore complex, wending in a curvilinear fashion along its margin in the general form of poorly exposed coalesced domes or localized arches.
To see quarried rock of horizon 1 (Steiner, et al. 1989a,b) drive west on Lake Road 0.3 mi to the Valley Cottage Fire Station and park along the West edge of the lot. The large blocks along the stream bank contain pegmatite dolerite clusters with sprays of augite locally reaching 6 cm.

STOP 7 WEST NYACK - COARSE PIGEONITE DOLERITE, INTRUSIVE RELATIONS AND LAVA DOME
The suggestion of a domal configuration at many points along the western contact is strongly supported by the lava dome situated southwest of the main quarry buildings. This dome was well exposed in the Fall of 1988, but has since been partially buried by crushed quarry rock.
Several facies are transected when walking or driving to Stop 8. In particular, trondhjemitic and granophyric varieties of the coarse dolerites, ultramafic segregation veins (Steiner, in preparation) and secondary "flowers" of chalcocite against malachite ovals along fracture systems may be visible. Unfortunately, many of these features have been completely removed by the quarrying operation.

STOP 8 WEST NYACK QUARRY - COARSE PIGEONITE DOLERITE WITH PEGMATITIC DOLERITE (COARSE AUGITE DOLERITE) PODS
Along the south end of the westernmost wall at the second level from the top, a coarse intrusive facies (H1, Steiner, et al., 1989a,b) invades diabases comparable to those exposed at Stop 6 along a narrow 12" dike. The dike shows an approximately 1" gap through which the magma welled up into adjacent rocks creating a balloon-like profile. This dike apparently represents an offshoot of the major contact which runs subparallel to the intersecting north wall. Pegmatite dolerite, comparable in many respects to the coarse augite dolerite of Stops 4 and 5 characterizes the general zone separating the two lithologies.

STOP 9. (OPTIONAL) WEST NYACK -SECOND UPPER CONTACT AND REDUCED ZONE
Park and walk up slope to prominent outcrop.
Here, a dip slope of the Triassic arkose (fossil fish locality) which is visible below abuts the Palisades. Portions of the metamorphosed sedimentary rock form a veneer over and are partially crosscut by offshoots of the dolerite. The tendency for the reduction of iron is again visible in the sedimentary rock.

A5: STRATIGRAPHY AND SEDIMENTOLOGY OF MIDDLE AND UPPER SILURIAN ROCKS AND AN ENIGMATIC DIAMICTITE, SOUTHEASTERN NEW YORK.
ANTHONY R. PRAVE and MOSES L. ALCALA
Dept. of Earth and Planetary Sciences
The City College of New York
New York, NY 10031
JACK B. EPSTEIN
Reston, VA 22092
During much of the Silurian Period, sedimentation patterns throughout the northern Appalachian Basin record west to northwest spreading of terrigenous and marginal marine clastics into a deeper water mud and carbonate basin (Cotter, 1988; Middleton, 1987). The clastics were derived from highlands uplifted during the Taconic orogeny in eastern Pennsylvania and southeastern New York. By the Late Silurian, active tectonism had ceased so that the (dis)equilibrium between sediment influx, basin subsidence and relative changes in sea level were the probable first-order variables controlling facies distribution.

A5: STRATIGRAPHY AND SEDIMENTOLOGY OF MIDDLE AND UPPER SILURIAN ROCKS AND AN ENIGMATIC DIAMICTITE, SOUTHEASTERN NEW YORK.

For the next 12 miles there are scattered outcrops of Martinsburg Fm.

Martinsburg-Shawangunk contact to left.

Excellent view of the Pocono Plateau
Parking area to right affords an excellent view of the Pocono Plateau; intermediate ridges are in the Middle Devonian Hamilton Group; Neversink Valley is floored by Upper Silurian - Lower Devonian rocks.

Middle Devonian Esopus Fm on right.

Ascent is on Wisconsinian till covering Upper Silurian - Lower Devonian rocks.

STOP 1A (PORT JERVIS AREA) BLOOMSBURG RED BEDS.
Epstein and Lyttle (1987) estimate that the Bloomsburg Red Beds is about 335 m thick near Port Jervis, NY. These strata can be traced continuously across New Jersey from Pennsylvania with little facies change. The Shawangunk tongue, which separates the main body of the Bloomsburg from the Bloomsburg tongue to the northeast, thins to a feather edge at this locality and is unmappable at a scale of 1:24000. For the sake of brevity, the description and interpretation of the Bloomsburg tongue will be given at this stop and at Stop 5 for the Shawangunk tongue. Alcala measured the section from the top of the Shawangunk Formation to the top of the Shawangunk tongue (Fig. 6). The Shawangunk tongue is only 5 m thick. It is described in detail at Stops 5 and 6B. The Bloomsburg between those two units is 65 m thick and consists of ~5 fining upward cycles. Discontinuous pebbly lags occur above a flat to scoured erosive base which is overlain by fine to coarse quartzose sandstones and lithic wackes. These in turn grade upward into reddish or grayish fine sandstones and siltstones generally overlain by blocky red mudstones. Thin, discontinuous stringers of coarser sandstones are common in these finer clastics.
The fine to coarse sandstones above the erosive base consist of several centimeters-to decimeters-thick cosets of trough cross-beds arranged in sigmoidal-and wedge-shaped bundles bounded by lateral accretion surfaces. The cosets generally thin upward. Planar cross-bedding and reactivation surfaces are present locally. Interference ripples are common on bed tops. The laterally continuous appearance of these sandstone beds is deceiving. They actually are broad. shallow channels that thin and pinch out into finer clastics (this will be seen from the top of the outcrop from a near normal-to-paleoflow view across I-84).
The overlying red and gray fine sandstones and siltstones contain abundant small-scale trough cross-bedding and flat lamination. Flaser and lenticular bedding, reactivation surfaces. interference ripples and burrows are common locally. The red mudstones generally contain desiccation cracks, horizontal and sub-vertical burrows and possible root traces. Calcrete zones and pedogenic slickensides are present in places.
These facies characteristics coupled with the paleocurrent data {Fig. 4) lead us to conclude that the Bloomsburg Red Beds record deposition in an intertidal environment. The broadly channeled, coarse sandstones were tidal channels that migrated through a finer detrital intertidal flat. Paleosols developed locally in a dry climate as indicated by the calcrete zones and dessication cracks. The thin, coarse sandstone stringers in the shales probably record exceptional tidal or storm events.
From the paleoflow data (Fig. 4), it is evident that ebb flows were dominant. The larger-scale trough cross-beds and lateral accretion surfaces make up the WNW-mode whereas the ESE-mode is more dependent on the presence of smaller bed forms. The lateral accretion surfaces and sigmoidal-shaped bundles indicate that tidal currents continuously mobilized the sandy substrate in a general WNW-ESE trend. These observations corresponds nicely with the pattern of tidal forcing one would expect given the Silurian paleogeographic reconstructions of Scotese et al. (1979) and Ziegler et al (1977) showing the Taconic highlands as a NE-trending belt that had an epeiric sea to the west (Fig. 7). We interpret the strong NNE mode on the rosette as representing a dominant lateral migration direction of the tidal channels due to the influence of a NE-flowing longshore current. Again this fits well with the paleoclimatic inferences of Ziegler et al. (1977) which indicate a southern, low-latitude high pressure system to the west of the Taconic highlands (Fig. 7): the counterclockwise circulation of surface winds associated with this high would force a NE-flowing longshore current along the western edge of the highlands. Thus, the paleoflow data indicate a dominant WNW ebb tide and a weaker ESE flood tide with a moderately influential NNE-flowing longshore current.
Unfortunately, the exposures are not quite good enough to determine spring-neap cycles. However, many of the coarser sandstones appear to have bundles of well-developed cosets and lesser-developed cosets which we have tentatively interpreted as full-vortex and slackening structures, respectively.

STOP 1B (PORT JERVIS AREA) TACONIC UNCONFORMITY BASAL SHAWANGUNK FORMATION.
The Shawangunk Formation is interpreted as recording a NW-flowing braided fluvial system draining the Taconic highlands (Yeakel, 1962; Smith, 1967; Epstein and Epstein, 1967, 1972) The facies and paleoflow data from this exposure (which is representative of the basal Shawangunk throughout the area) support that interpretation (at least for the basal part of the formation): thick-bedded, massive to large-scale trough cross-bedded, quartz-pebble conglomerate and coarse quartzite yielding uniquadrant paleocurrent rosettes (Fig. 8).
Here the Shawangunk rests unconformably on shale and graywacke of the Martinsburg Formation. The angular discordance is 5°. Along the contact is a 5 to 15 cm thick fault gouge containing angular Martinsburg fragments in a dark-yellowish orange clay matrix. Thus, this contact also represents a zone of tectonic displacement, the amount of which is not known. For a complete discussion of the relative effects of the Taconic and Alleghanian orogenies, see Epstein and Lyttle (1987).

Travel along south slope of Shawangunk Mtn
Travel along south slope of Shawangunk Mtn: note occasional Martinsburg outcrops.

STOP 2 (OTISVILLE). DIAMICTITE AT THE TACONIC UNCONFORMITY
This classic exposure of the Taconic unconformity along the railroad cut was visited on the 59th NYSGA Meeting (Epstein and Lyttle. 1987). This discussion is a summary of that visit.
The quarry across the road is in the Shawangunk Formation: it is about 2 km along strike from the type locality of the "Otisville Shale" of Swartz and Swartz (1931). As is evident, shale is meager. The "Otisville" is poorly-defined and should be discarded.
The shales and siltstones of the Martinsburg dip moderately to the northwest, whereas, above the unconformity, the quartz-pebble conglomerate of the Shawangunk dips 16° less. The basal surface of the Shawangunk is irregular and displays downward projecting mullions having a few centimeters of relief and spacings up to a few decimeters. Bed-parallel shearing is developed in places above the unconformity.
Along the contact is a diamictite as much as 30 cm thick with sharp, unconformable upper and lower contacts. Within the mud matrix are angular clasts of the Martinsburg (in places large parts of the Martinsburg appear to have been bodily incorporated into this zone) as well as angular to rounded "exotic" pebbles not present in the underlying bedrock: clean and pyritic quartz arenite, feldspathic and chloritic sandstone, cross-laminated feldspathic conglomeratic quartzite, siliceous and micaceous siltstone and red siltstone. Weathering rinds and pits are present on some of the pebbles and. along with the rounding, are evidence for subaerial transport and exposure prior to deposition. The above indicates that the diamictite is a product of mass wasting, possibly a colluvial gravel.
Also in this zone is a grayish gouge with slickensided quartz veins. This gouge and the mullions are typical of many of the Martinsburg-Shawangunk contacts in southeastern New York and indicate that the unconformity is a plane of movement, the displacement along which is not known.

Shawangunk Fm to right.

Shawangunk mine (Pb-Zn) on top of Shawangunk Mtn to right (Gray, 1961).

STOP 3 (BEAR HILL). LUNCH AND SHAWANGUNK FORMATION CROSS-BEDS.
These nearly flat-lying beds of the lower part of the Shawangunk Formation are near the crest of the Ellenville arch, a broad, open fold of Alleghanian age (Epstein and Lyttle. 1987). The basal 30 m of the formation are exposed here and consist primarily of quartz-pebble conglomerate and medium to pebbly quartzite composed of decimeter-scale cosets of trough cross-bedding. A well-developed joint pattern and numerous exposures of bedding surfaces afford an excellent opportunity to examine the relationship between quasi-3-D views and plan views of trough cross-bedding. These exposures can be used to discuss the 'proper' methods of obtaining paleoflow data from troughs.

Martinsburg Fm exposure to left.

STOP 4 (ELLENVILLE). SHALE-CHIP GRAVEL AT TACONIC UNCONFORMITY.
This exposure also was visited on the 59th NYSGA Meeting (Epstein and Lyttle, 1987) but it is a problematic exposure worthy of further puzzlement. Your opinions are encouraged.
The basal Shawangunk forms a slight overhang which affords a view of an in-place, shale-chip gravel developed beneath the unconformity. The shale-chip gravel is at least 60 cm thick and consists of very well sorted shale chips about 3 cm in length derived from the underlying Martinsburg (exposed about 6 m below this outcrop). It is crudely foliated parallel to bedding in the Shawangunk. This shale-chip gravel is similar to those of Pleistocene age derived from Paleozoic shales in many areas in Pennsylvania and New Jersey.
The excellent sorting suggests winnowing of the gravel during transport. This gravel and the diamictite observed at Stop 2 indicate that the Martinsburg surface, uplifted during the Taconic orogeny, was subaerially exposed and covered by colluvium and gravels. Much of this material was subsequently removed by erosion and the remnants were buried by the Shawangunk conglomerates. There are no known nearby sources for the exotic pebbles in the diamictite. As stated earlier, it is possible that they were derived from now-eroded Taconic nappes.

STOP 5 (ELLENVILLE). BLOOMSBURG AND SHAWANGUNK TONGUES.
This section was measured by Alcala. The Bloomsburg tongue is 48 m thick and consists of 37 fining upward cycles (Fig. 9). Seven meters of the Shawangunk tongue are exposed. The contact between the Shawangunk Fm and Bloomsburg tongue is gradational as is the contact between the two tongues.
The fining-upward cycles in the Bloomsburg tongue are similar to but contain more shale and mudstone than the Bloomsburg strata seen at Stop 1A. The sandstones forming the basal parts of cycles are the same. Quartz and lithic wackes that consist of sets and cosets of trough cross-strata are arranged in sigmoidal shaped bundles commonly bounded by lateral accretion surfaces. Given the same facies characteristics and paleoflow trends (Fig. 4), we interpret this section similarly. The dominant WNW-ESE bipolar rosettes indicate tidal flow. The data obtained from the larger bed forms again suggest a stronger ebb tide relative to the flood tide. The NNE mode indicates the continuing influence of northeast flowing longshore currents in forcing a preferred NNE migration direction of tidal channels. The finer clastics represent the intertidal flats. We interpret their greater proportion here as indicating deposition primarily in upper intertidal flat areas.
The first tabular-appearing quartz arenite bed marks of the Shawangunk tongue which consists predominantly of thick-bedded, fine to medium quartz arenites with minor shale and rare red shale. Shales occur as thin partings or layers up to 20 cm in thickness. Pebbly quartzite occurs in places (such a bed occurs about 4 m above the base here and at the section near Wurtsboro}. Bases of beds are erosive and flat to shallowly scoured and pebbly lags occur locally. Trough cross-bedding is common and occurs in sets and cosets 0.1 to 1 m thick. Planar cross-bedding and flat lamination occur locally; some of the finer sandstones contain small-scale cross-stratification. In all cases, laminations consist of alternating light-dark couplets. some of the foresets are defined by flat mud clasts. Interference ripples and, rarely, trails and burrows can be observed on some bed surfaces.
On the basis of the facies characteristics and paleocurrent data (Fig. 4), we interpret the Shawangunk tongue as a sub-tidal (and possible lower intertidal) sand body. The clustering of flow data in the western hemisphere of the rosettes (i.e. from 180° to 360°) indicates primarily offshore-directed transport, probably by strong ebb tides and possibly by rip and storm currents (note, however, that no hummocky or swaley cross-stratification has been observed to support a storm influence). The NNE mode indicates sediment transport by longshore currents. We interpret the 'clean' quartz arenitic character of theses sandstones as resulting from selective sorting by marine currents (the coarser, 'dirtier' sands were 'locked-up' in the tidal channels of the Bloomsburg). The presence of interference ripples and rare trace fossils further supports this interpretation.
Modern tidal flats display a progressive facies change. Upper intertidal areas are finer-grained, less and smaller channeled relative to the well-channeled, mid intertidal areas whereas sub-tidal zones are sandy (Klein, 1985). Examination of the measured sections (Figs. 6, 9, 11) indicates such a trend. The lower part of the Bloomsburg tongue contains more fines than does the uppermost part, i.e., deposition initially occurred in middle and upper areas of an intertidal environment with subsequent deposition in lower intertidal environments. As the transgressive event progressed, those deposits were covered by sandy subtidal deposits of the Shawangunk tongue.

STOP 6A (WURTSBORO). HIGH FALLS SHALE.
The High Falls Shale and correlative Poxono Island Formation are poorly exposed in this area. The nearest exposures to this locality are 34 km to the northeast near Accord, NY and about a similar distance to the southwest in New Jersey. The sections at Stop 6 (A & B) were measured by Alcala.
The section of the High Falls Shale is 10 m thick (Fig. 10), but it is incomplete (both contacts are covered). The High Falls consists of fine to medium quartzose sandstones with minor, laterally discontinuous greenish and reddish shale layers. Beds are composed of large scale trough cross-bedded sets and cosets as much as 80 cm thick. Lateral accretion surfaces and, less commonly, reactivation surfaces bound many of the sets. Planar cross-bedding, flat lamination. desiccation cracks. symmetrical ripples. and burrows and trails are moderately common. Bases of beds are flat but erosive and have local lags. Bed tops generally are mantled with interference ripples.
Examination of the paleocurrent rosettes (Fig. 10) clearly indicates that these are tidal deposits. The sedimentary structures and composition suggest lower intertidal to sub-tidal settings. The WNW-directed ebb tide was dominant. A less developed NE mode is once again interpreted as recording the influence of longshore currents. Curiously, these flows are rotated slightly clockwise relative to those of the Bloomsburg and Shawangunk tongues. We tentatively conclude that this probably indicates a slight reorientation of the paleostrandline to a more northeasterly direction. The NE-trend of wave ripple crests (Fig. 10) adds some credence to this speculation.

STOP 6B. (WURTSBORO). BLOOMSBURG AND SHAWANGUNK TONGUES.
The Bloomsburg and Shawangunk tongues are best exposed at this locality which is a normal-to-paleoflow view. Contacts between the "tongues" and the underlying Shawangunk Fm are gradational. The Bloomsburg tongue is 58 m thick and consists of 41 fining upward cycles (Fig. 11). The Shawangunk tongue is nearly complete (top contact is covered) and is 34 m in thickness. The facies here are similar to those observed at Stops lA and 5 except that they are thicker and have more paleosol and caliche layers. Thus, given the same facies and paleoflow trends (Fig. 4), the same interpretation is proposed: the Bloomsburg tongue is an intertidal deposit recording WNW-ESE ebb-flood tides and the Shawangunk tongue is a sub-tidal deposit. Both "tongues" were influenced by NNE-flowing longshore current.

Taconic unconformity and Martinsburg Fm
We will pass the Taconic unconformity and a long exposure of Martinsburg Fm described by Epstein and Lyttle (1987, p. C-71-73); under overpass is a slump structure to the right.

A6: EARTHQUAKE ACTIVITY IN THE GREATER NEW YORK CITY AREA: A FAULTFINDER'S GUIDE
ALAN L. KAFKA
Weston Observatory
Department of Geology and Geophysics
Boston College
Weston, MA 02193
MARGARET A. WINSLOW
Department of Earth and Planetary Sciences
City College of CUNY
New York, NY 10031
NOELL. BARSTOW
Rondout Associates, Inc.
Stone Ridge, NY 12484
INTRODUCTION: EARTHQUAKES IN THE NORTHEASTERN UNITED STATES
Although the area within a 100 km radius of New York City is clearly not as seismically active as most areas near plate boundaries, this area has had its share of moderate earthquake activity. For most earthquakes in the interior of the North American plate -- unlike the situation along plate boundaries -- it is not clear whether geologic faults mapped at the surface are the faults along which the earthquakes are occurring. The purpose of this field trip is to examine several geologic features in the greater New York City (NYC) area that might be related to earthquake activity. As we proceed, the following question will be addressed:
Are seismically active faults in the NYC area delineated by geological features that are observable at the earth's surface?
To understand earthquake phenomena in the NYC area, it is helpful to picture this area in the context of earthquake activity throughout the northeastern United States (NEUS). The NEUS has one of the longest records of reported earthquake activity in North America (Fig. 1). Earthquake activity was noticed in this region by early European settlers, and as the population density grew, an increasing number of earthquakes were reported. These earthquakes were usually minor, but sometimes not-so-minor, and occasionally even caused damage. Instrumental seismic monitoring in the NEUS began in the early 1900's, and routine reporting of instrumentally recorded earthquakes began in 1938 with the initiation of the Northeastern Seismic Association (Linehan and Leet, 1942). The first telemetered regional seismic network was operated in northern New England by Weston Observatory from 1962 to 1968, but it was not until the early 1970's that the present regional networks were established. The number of seismic stations in the NEUS steadily increased between 1970 and 1974. By 1975, a number of institutions operating seismic networks in the region formed a cooperative group known as the Northeastern United States Seismic Network (NEUSSN; Fig. 2). The data recorded by the NEUSSN has enhanced our ability to study the regional seismic activity. Analysis of these data provides insight into the possible causes of the earthquakes. RAMAPO FAULT FIELD TRIP
In this field trip, we will examine geologic features that might be related to earthquakes, and we will look for characteristics that might identify active and nonactive faults. Of several geomorphological features possibly associated with Quaternary age faulting in the NEUS, a few well-defined examples stand out in the NYC area (Figs. 6b and 7). These features appear to concentrate along the Ramapo Fault zone and the Hudson River valley. This field trip will visit several localities along the distinctive topographic lineament of the Ramapo fault system where geomorphic features suggest Quaternary displacements. These features include the following:
(1) Fault scarps (primary and secondary) along the length of the Ramapo Fault system.
(2) Different heights, numbers, and ages of river terraces across the Ramapo and Mahwah Rivers.
(3) Asymmetric valleys with river running against the faulted side of the valley. This suggests continued tilting of fault blocks (e.g. Ramapo and Mahwah Rivers).
(4) Narrow zones of unconsolidated fault gouge in soil along the Ramapo Fault.
(5) Repeated offset tributaries to the Ramapo river suggesting dextral shear.
(6) Migrated meander loops of the Ramapo River suggesting dextral shear.
Some features, such as offset tributaries, valleys, and asymmetric meanders are better observed on maps and aerial photos than on a field trip. Other tectonically controlled landforms, such as reversal of river drainage direction, changes in tilt of the Palisades sill, offsets in the sill, and abrupt changes in height of its basal contact, post-date the early Mesozoic, but cannot be proven to be Quaternary in age.
The field trip follows the trace of the Ramapo fault along the Ramapo River in NJ and the Mahwah River in NY. South of Suffern, the Ramapo fault system forms a well-defined linear feature. At Suffern, however, it appears to split into two or more splays beneath a floodplain. The lineament following the Mahwah River marks the boundary between the Hudson Highlands and the Newark Basin. The field trip will follow the Mahwah River to its headwaters, where the Ramapo fault appears to split or be truncated by the Willow Grove Fault. North of Willow Grove, a NE-trending fault can be followed to the Hudson River.
The presence of greater numbers and heights of river terraces on the west side of the Ramapo and Mahwah River valleys along the boundary between the Hudson Highlands and Newark Basin support uplift of the NW side of the valley, the Hudson Highlands, along the Ramapo fault. The regular spacing of the terraces down to the present river edge suggests episodic uplift during the Quaternary. The absence of terraces on the SE side of the river valleys appears to be independent of lithology. In other words, the river terraces on the NW side appear to be tectonic.
Several right-slip offsets of cross-strike (SE-flowing) tributaries occur where they empty into the Ramapo River. Two meanders of the Ramapo also appear to be structurally controlled. They also support Quaternary age right-slip motion.

A6: EARTHQUAKE ACTIVITY IN THE GREATER NEW YORK CITY AREA: A FAULTFINDER'S GUIDE

The Ramapo fault lies to the west between the Ramapo Mountains and the Ramapo River.

STOP 1. DEERHAVEN.
The topography rises toward the west in discrete steps forming several discontinuous terraces on the NW side of the Ramapo River valley. They are not matched on the SE side. The terraces have formed on both unconsolidated sediment and bedrock. Notice how the river flows to the NW side of the valley along most of its length, regardless of the topographic and bedrock changes on the SE side of the river. This suggests westward tilting of the valley toward the fault. Bear Swamp Brook cuts perpendicular to the structure (SE). Upstream its banks are unequal in height. The NE side appears to be higher, as is the case for several other cross-strike streams that cross the Ramapo fault trace.

The houses are built on a higher level.

Take a left at Deerhaven Road which follows a higher level.

Crystalline rocks
At fork make right and go up hill to discontinuous outcrops of crystalline rocks.

STOP 2. RAMAPO RESERVATION.
This stop involves a 30 minute round-trip hike. Follow a trail directly west to a bridge over the Ramapo River. Cross abandoned meander loops and marshy areas. Across the river is a large lake in a wide, flat flood plain. Begin to climb upward. Return to parking area. Exit to south only.

STOP 3. PAVILION ROAD.
Near the bottom of the hill are exposures of slickensided crystalline rock, one of the few outcrops of the Ramapo fault. These well-developed slickensides of unknown age suggest dip-slip movement with a minor right-slip component. Slickensided fault surface averages N 55-65°E, and dips 60-65°SE. Slickenlines pitch N 15°E, 55°SE.

Terrace levels
Route 202 runs along one terrace level above the Mahwah River that is not present on the eastern side. Some discontinuous, higher terrace levels can be seen on the west side of the road.

STOP 4. SKY MEADOW ROAD.
Proceed southwest and west down across the Mahwah River, driving toward the fault. The road climbs four well-developed levels between the river and the fault. Power lines on the mountain follow a natural bench for several kilometers. The river valley is terraced on the NW side, and is hummocky and irregular on the SE side. Drilling data near here suggest that a Triassic age vesicular lava flow, over 450 ft thick, accumulated near the border fault (Ratcliffe, 1980). Local relief at the edge of the basin at the time was approximately 450 feet (Ratcliffe, 1980).

This road runs parallel to the Ramapo fault.
The river valley narrows toward the north. The fault lies on the west side of the river valley. The topography rises on both sides of the road. However, on the east side, the landforms are hummocky and irregular, whereas on the west side of the river, there are distinct levels. The power lines follow one wide terrace.

STOP 5. CALL HOLLOW ROAD.
North of Ladentown and just south of Willow Grove on Call Hollow Road the ridge defining the eastern edge of the Hudson Highlands begins to turn north as you approach the Willow Grove Valley. The Mahwah River valley pinches out. The terrace along which the power lines have run also ends here. The lines cross the road to join a buried gas line that follows the NW-trending steep ridges and narrow valley. These features also truncate in Willow Grove valley. The gas line is buried in intensely fractured material. Triassic basalts on the W side of the road tilt SE.

STOP 6. WILLOW GROVE.
The Ramapo fault cannot be easily followed north of Willow Grove valley. The fault appears to trend more toward the north and to be offset about 4 km right laterally by an E-SE-trending fault that follows Minisceongo Creek through Willow Grove valley. The creek experiences several 90° bends near Willow Grove. The terrain to the north and west of Willow Grove consists of massive, rounded hills with short, non-linear valleys as is typical of the topography west of the Ramapo fault. An alternative suggestion is that Willow Grove valley could be a pull-apart developed between the diverging splays of the Ramapo and Theills faults. The saddle to the south consists of highly brecciated rock fragments.

STOP 7. THEILLS ROAD.
Here the best candidate for a continuation of the Ramapo fault is seen to follow the NE-trending section of Cedar Pond Brook. Terraces are seen only on the NW side of the stream valley. Once again it represents hilly Hudson Highlands juxtaposed next to Quaternary sediments. Notice here, too, that there are river terraces only on the NW side of the valley, and that the SE side is lower. Between Call Hollow Road and Theills Road is a possible horst block of Proterozoic gneiss (Ratcliffe, 1980). NE striking features in the area do not seem to offset lava flows, but discontinuous exposures do not allow confirmation of any post-Mesozoic movements, except for tilting of basaltic layers.

Cedar Flats Road and Matt Farm Road parallel the fault.

The road detours around Lake Bullowc.
The fault continues on NW side of the lake. The road then resumes its trend parallel to the possible fault.

STOP 8. MOTT FARM ROAD.
Slickensided surfaces, vertical to steeply dipping. Some slickensided surfaces dip steeply SW with slickenlines plunging 65-75°SW. Other surfaces dip steeply NW with slickenlines plunging 75-80°NE. Several fracture patterns are also evident.

Pass outcrop of brecciated rock with complex fracture patterns.

Natural terrace 2-3 meters high
At Tompkins Lake, follow road around toward north on natural terrace 2-3 meters high which is not present on the other side. Steep talus slope rises to west.

STOP 9. TOMPKINS LAKE.
View of terrace and former lake level.

STOP 10. TOMPKINS COVE QUARRY.
Cambro-Ordovician limestone beds with black chert interbeds and bedding-parallel stylolites trend N 10-20°E and dip 55-65°SE. Calcite-filled fractures cut the outcrop at N 20-30°E and dip 40-42°SW. The brittle features could be related to the Ramapo fault system. See Ratcliffe (1980) for further information. The quarry reveals eight fault zones that disrupt the structural continuity (Ratcliffe. 1980). The faults are identifiable as red or green zones of clay gouge and phyllonite, best seen on the south face of the quarry on all levels. These faults are SE-dipping reverse faults with left-or right-lateral offsets. Despite a youthful appearance, they are associated with folds (Ratcliffe, 1980) although they appear to have been reactivated to produce the clay gouge and slickensides. Ratcliffe suggests that the faults are pre-Mesozoic thrusts that were reactivated during the Triassic as normal and strike-slip faults.

Slickensided surfaces on a new outcrop
Slickensided surfaces on a new outcrop exposed on left at mile point 36.0. No stop here. As you proceed north on Route 9W, the Ramapo fault or Matt Farm Road fault runs close to the river. Route 9W is adjacent to or on the fault. Recent construction on Route 9W has revealed rich zones of slickensides, intensely fractured rock, and brecciated zones along this stretch of road.

STOP 11. JONES POINT.
Jones Point is built on a series of low terraces. Walk along the railroad bed toward the north. STAY OFF THE TRACKS! The fault also outcrops immediately behind the house. At the intersection of the road and the railroad tracks is a polished and grooved outcrop that marks the end of the crystalline rocks in this area. The steep, SE-facing fault surface is polished and has sub-horizontal glacial grooves. Small normal faults are seem on the exposure. Note that where the fault crosses the Hudson River, the river abruptly changes direction. The Indian Point power plant is located directly across the Hudson River to the east. The Canopus and Peekskill River valleys are visible from here.

View a possible older terrace and till remnant near a former chapel.

STOP 12. ABANDONED QUARRY.
The Ramapo fault cuts the south side of the hill. Between this site and the river are several low terraces. Note truncated (over-steepened) spurs here. Walking west over a wide flat area, there is a possible scarp and sag pond in the area not exploited by the former quarry. The small scarp is 1-1.5 meters high. The terrace is developed on stream cobbles of a former river level.

STOP 13. BEAR MOUNTAIN INN.
Refreshments, etc. The only scheduled rest stop.

STOP 14. PERKINS MEMORIAL DRIVE LOOKOUT.
The Ramapo fault crosses the Hudson River to enter the Peekskill Hollow or Canopus River valleys. Sharp bends in the Hudson River appear to be structurally controlled. Each linear river bend, when projected onshore in Westchester or Rockland County, is associated with an anomalously linear river valley that follows the same strike. Some examples include the Ramapo, Mahwah, Cedar Pond, Minisceongo, Canopus, Leeds Cove, and Peekskill Hollow valleys. The terrace on the NW side of the Peekskill river appears to be higher than on the east side. On a regional scale, the Hudson River is linear and trends N-S, except where crystalline rocks cross it. At least one of the NE-trending segments occurs where the Ramapo fault crosses the Hudson. Another SE jog occurs where the Willow Grove fault crosses the river. The trend of another sharp bend in the Hudson River toward the SE follows a lineament onshore into Westchester County along the linear Leeds Cove valley. This latter example suggests that the Ramapo fault offsets one kilometer right-laterally a possible fault beneath the Hudson River.

A7: ROCK SLOPE STABILITY: DESIGN, CONSTRUCTION AND REMEDIAL TREATMENT
CLAYTON L. BOLTON JR.
Engineering Geology Section
Soil Mechanics Bureau
New York State Department of Transportation
The design and construction of rock slopes with emphasis on stability began with the ability to drill and blast on an alignment whereby the final slope product was sound and durable and free of potential rock fall hazards. The first attempt at constructing a planar surface in rock was not for a highway but for construction of the sides of an intake channel for the "Niagara Power Project" in Niagara Falls, New York. The extra effort to develop a vertical planar surface for the intake channel was not to prevent potential rock falls but to establish a surface whereby the concrete channel wall liners could be built with a minimum overrun in concrete quantities. (When one considers that the majority of the listed 38,846,000 cubic yards of excavation was in rock, and that several million square feet of rock face had to be prepared within a tolerance of six (6) inches, it is easy to see that quite a problem was presented to the various contractors to keep from overbreaking beyond the payline, or "B" line, as it was called, with conventional methods of drilling and blasting). The method for constructing the planar face was named "presplitting".
The results of "presplitting" in constructing the vertical planar rock wall were so good that it soon was considered to be worthy of utilization in establishing minimum maintenance, hazard free rock faces for highways, tunnels, building foundation excavations and other locations where rock stability is a major concern. New York State Department of Transportation incorporated "presplitting" in its EXCAVATION SPECIFICATIONS on August 27, 1970 by inclusion in Addenda 49 to the January 2, 1962 PUBLIC WORKS SPECIFICATIONS. Once the "presplitting" tool was in place for constructing a stable rock slope, the Engineering Geologist could then put his knowledge to work to establish a suitable rock slope design. This method of construction leading to proper design is another example of empirical knowledge's ability to make theory, fact.

A7: ROCK SLOPE STABILITY: DESIGN, CONSTRUCTION AND REMEDIAL TREATMENT

STOP 1: Slope has two (2) lifts.
A few bolts are in the top lift across from the west end of the parking area. There are more bolts near the location marker.

STOP 2: Slope has two (2) lifts.
A gabion wall is installed on the bench. There are numerous bolts in the upper face. A large dike cuts through the center of the face.

STOP 3: Between parking area and bridge
There are several areas between the the parking area and the Bridge which have rock catchment fences, rock bolts and/or buttresses.

STOP 4: Rock Slope Stabilization Project.
Slope is being trimmed to an inclination of 1 vertical on 1 horizontal.

STOP 5: Shoulder is being widened
Shoulder is being widened and rock slope is being trimmed to inclination of 2 vertical on 1 horizontal.

STOP 6: Vertical slopes
Vertical slopes on both sides of highway and in median. Massive wedge failure scar on south slope. (Fig. 2)

STOP 7: Mylonite zones, rock bolts
Several areas showing thick mylonite zones, rock bolts & wedge failures.

Catchment mesh

STOP 8: Rock slopes on both sides of highway.
There is a wide bench on the south side with a guard rail installed at the edge to act as a catchment.

A8: DEGLACIAL HISTORY AND ENVIRONMENTS OF THE UPPER WALLKILL VALLEY
G. GORDON CONNALLY
12 University Avenue
Buffalo, NY 14214
LES SIRKIN
Department of Earth Sciences
Adelphi University
Garden City, NY 11530
DONALD H. CADWELL
Room 3140
Albany, NY 12230
The glacial history of the Wallkill Valley of eastern New York first was described by Connally and Sirkin (1967) in the guidebook for the 39th annual meeting of NYSGA. Prior to their interest, the area had received scant attention. It was mentioned peripherally by Woodworth (1905) and discussed in abstract by Connally (1966). The only previous detailed work was a study of preglacial lakes reported by Adams (1934).
Before commencing the joint study, Connally and Sirkin established restrictive criteria for locating the bogs that have become the standard sections: 1) some aspect of the peat bog must be directly linked to some specific geomorphic event, 2) the bog must have a high, unbreached rim with exclusively internal drainage, and 3) a deep section must directly overlie glacial sediments. We refer to this strategy as an integrated approach and contrast it with the grab-sample approach of others.
Following the tenets of the integrated approach, Connally and Sirkin (1970) refined interpretations. They discussed the valley again in the context of the entire Hudson-Champlain Lobe (Connally and Sirkin, 1973) and then Connally (1983) and Connally and Sirkin (1986) discussed regional correlations.
In the summer of 1988, Connally completed a 25-year project, mapping the entire Wallkill Valley at a scale of 1:24,000. The 7.5' maps that cover the New York portion are on open file in the New York State Geological Survey in Albany, New York. NYSGS supported the later phases of this project, from 1983 through 1988, under the aegis of Don Cadwell. The maps are part of the data base for the Lower Hudson sheet of the Surficial Geologic Map of New York. During NYSGS sponsorship, new landforms have been recognized, new ideas have been generated in the field of glacial geology, and new interpretations have been applied to the Wallkill Valley.

A8: DEGLACIAL HISTORY AND ENVIRONMENTS OF THE UPPER WALLKILL VALLEY

Esker complex on left
Esker complex on left marking the Pellets Island Moraine in the Rutgers Creek valley

Dead ice sink on right
Dead ice sink on right; in-wash is mined for sand and gravel

Lake Fairchild/Lake Dyson lake bottom
Lake Fairchild/Lake Dyson lake bottom at left, now the Wallkill River floodplain

View of inversion ridge
The inversion ridge formerly identified as the "Sussex Moraine" is visible at 11:00 o'clock

STOP 1. INTERNAL STRUCTURE OF AN INVERSION RIDGE
NOTE! Permission to enter this property has been obtained for this trip ONLY! RAIA Industries, in Hamburg, New Jersey, probably will NOT grant permission to individuals.
Walk down the inversion ridge to the exposures in the active sand and gravel pit. This feature formerly was described as the "Sussex Moraine". What type of depositional environment can you infer from the sedimentary structures? What and where was the source for this sediment? Where was the glacier? In what condition was the ice?
As you travel to Stop 2, you will cross the upland drainage system that fed onto the ice to form this feature. Keep your eye peeled for this at mile 26.1.

The head of the inversion ridge drainage channel
Upland drainage system strewn with boulders to the right, dead ice and inversion ridges (then, stream channels in the ice) to the left.

Lake Fairchild/Lake Dyson lake bottom ahead, on left.

Pochuck Creek valley to right at 2:00 o'clock

Bridge across Pochuck Creek

Orange County muck-lands
Orange County muck-lands on both sides of the road for next 5 mi. This is the last remnant of Glacial Lakes Fairchild and Dyson.

A cluster of 5 drumlins forms "Big Island"

The Pellets Island Moraine crosses the Orange County muck-lands.

Drive up the distal slope of the Pellets Island Moraine

STOP 2. INTERNAL STRUCTURE OF THE PELLETS ISLAND MORAINE
NOTE! You must obtain permission from Gurda Gardens, Ltd. to enter this sand and gravel pit.
Walk into the sand pit on the west side of Cedar Swamp Road. This pit is about 5 km east of the type locality for the Pellets Island Moraine at Pellets Island. The old pit, visited in 1967, is badly slumped today. What type of depositional environment can you infer from the sedimentary structures? What and where was the source for the sediment? Where was the glacier? In what condition was the ice? How does this deposit contrast with that at Stop 1?

Bridge across Wallkill River

STOP 3. SMILEY FARM ESKER(?)
NOTE! DO NOT EVEN ASK! This popular stop was included on the 1967 trip. Since then, the Smiley's have been deluged with visitors - most of whom have not even asked permission. For many reasons, the Smiley's DO NOT WANT PEOPLE VISITING THEIR WORKING FARM. DO NOT EVEN BOTHER TO ASK PERMISSION! We have obtained permission for this trip only--and only because of our long association with the Smileys and with this stop.
Climb the hill on the east side of the dirt access road. Gather at the top of the hill, that is located about midway between the Pellets Island and Wallkill Moraines. See if you can come up with an explanation better than 1967's when the term "moulin kame" was bandied about.

LUNCH STOP. THOMAS BULL MEMORIAL PARK
This is the same lunch stop used in 1967. In May of 1967 it was so cold (it snowed in the Catskills) that Orange County thought we would cancel lunch and didn't even have the restrooms open for us. They are up the hill, on the left. If the weather is bad, we have reserved the picnic pavilion.

Wallkill Moraine
Wallkill Moraine visible on right from 1:00 o'clock to 4:00 o'clock.

Wallkill Moraine outwash apron
Wallkill Moraine outwash apron deposited at the edge of Glacial Lake Dyson at ±400 ft.

STOP 4. A ROADSIDE BOG
At this stop we will demonstrate the technique used in retrieving a core from a subsurface organic deposit. Although this site does not meet the restrictive criteria established by Connally and Sirkin, it is conveniently close to the road as a demonstration site. First we will probe the depth of the organic sediment and then retrieve a sequential core using a Davis Piston Corer. We also will discuss surface vegetation and the subsurface pollen stratigraphy of the Wallkill Valley.

Climb the distal slope of the Wallkill Moraine

"Inner" Wallkill Moraine
The road climbs the distal slope of the "inner" Wallkill Moraine

STOP 5. ESKER FEEDER FOR THE WALLKILL MORAINE
CAUTION! You are on the property of the Wallkill State Prison. If you do not obtain permission before visiting this pit you may expect a visit from one or more armed officers.
There is little exposure left at this site that is about 4 km north of the inner Wallkill Moraine. Look about for clasts that you can identify as white Shawangunk conglomerate or orthoquartzite sandstone. Take in the splendid view of the bare rock cliffs of Shawangunk conglomerate·--these are made famous by mountain climbers from all over the northeast. Why are these cliffs so fresh? Why is the escarpment to the south covered by a blanket of talus? What is the source of the sediment for this huge esker that flanks the bottom land channel of the Wallkill River?
Look for evidence of Shawangunk conglomerate as you travel to Stop 6.

The foot of a feeder esker
The foot of a feeder esker appears on the left; the road parallels this esker up the hill to the base of the Shawangunk cliffs.

STOP 6. HEAD OF FEEDER ESKER AND VIEW OF SHAWANGUNK CLIFFS
This stop enables you to view the huge, block-sized clasts of Shawangunk conglomerate that were frozen in time as they were moving down into or onto the Woodfordian glacier. Evidently the hydraulic situation along the cliff was similar to a bergschrund on a cirque headwall. The plucking of these huge blocks resulted in a cleanly exposed rock face (or free face) once the glacier receded. Why don't you see these large blocks down in the valley? Why are these cliffs not covered with talus as are those to the south?
As you drive down into the valley, you will pass a second massive esker on your left. Look at the change in the size of the Shawangunk conglomerate clasts as you continue down to the valley floor.

B1: LATE PALEOZOIC DEFORMATION IN THE RESERVOIR FAULT ZONE AND GREEN POND OUTLIER, NEW JERSEY HIGHLANDS
L.D. MALIZZI AND A.E. GATES
Newark, New Jersey 07102
The New Jersey Highlands are part of the Precambrian Reading Prong which extends from Massachusetts to Pennsylvania (Fig. 1a). The field study area is in north-central New Jersey and contains the Reservoir Fault zone and Green Pond outlier.
The Reservoir Fault zone forms the boundary between the western side of the Paleozoic sedimentary rocks of the Green Pond outlier and Grenville gneisses of the New Jersey Highlands (Fig. 1b). The Paleozoic Green Pond outlier locally contains northwest-dipping reverse faults (Herman, 1987; Herman and Mitchell, 1989) and southeast-verging folds. These structures indicate southeast directed transport which is enigmatic with respect to the rest of the Appalachian foreland fold and thrust belt.
The major structure in the area is the northeast-striking Reservoir Fault zone. The fault zone is a high angle 100 m wide cataclasite and semi-brittle mylonite zone, which is composed predominantly of Grenville gneisses. Numerous theories have been presented for the deformational history of the Reservoir Fault zone including Mesozoic normal faulting (Lewis and Kummel, 1912; Ratcliffe, 1980), Proterozoic wrench faulting (Helenek, 1987), Alleghanian sinistral strike-slip faulting (Mitchell and Forsythe, 1988), and Alleghanian reverse faulting (Herman and Mitchell, 1989). Recent work by Malizzi and Gates (1989) indicates that the Reservoir Fault zone and Green Pond outlier form the east side of a positive flower structure that formed through Late Paleozoic dextral transpression with later sinistral strike-slip reactivation.

B1: LATE PALEOZOIC DEFORMATION IN THE RESERVOIR FAULT ZONE AND GREEN POND OUTLIER, NEW JERSEY HIGHLANDS

STOP 1. CONJUGATE REVERSE FAULTS IN THE DEVONIAN SKUNNEMUNK CONGLOMERATE
This is a typical exposure of the Devonian Skunnemunk conglomerate (Fig. lb). This conglomerate is a very coarse-grained quartz pebble conglomerate with a red-purple medium-grained sandstone matrix which is thin to very thick bedded. The conglomerate contains medium-grained red sandstone interbeds and is locally crossbedded.
The conglomerate exhibits bedding and cleavage with attitudes of N47E 48SE and N45E 90SE, respectively. This exposure contains conjugate reverse faults (Fig. 4b). The attitudes of the reverse faults are N57E 47SE and N52E 65NW. Movement sense is indicated by fibrous stepped quartz slickenfibers. The northwest-dipping reverse fault contains slickenfibers with an average attitude of N49E 73N. The reverse faults were produced by Late Paleozoic transpression.
The exposure also contains sinistral en-echelon quartz vein arrays. The individual veins in the vein array are spaced 10 cm apart and reflect small scale displacement. The vein arrays were developed by a north-south compression which was probably produced by Mesozoic pre-rifting sinistral strike-slip movement.

STOP 2. STRIKE-SLIP AND REVERSE STRUCTURES IN THE PRECAMBRIAN PYROXENE-BIOTITE GRANITE GNEISS
This is a typical exposure of the granite gneisses that comprise the New Jersey Highlands (Fig. 1b). The rock is coarse-grained, brown to dark greenish-gray pyroxene-biotite granite to alkali-feldspar granite gneiss which is brown to dark greenish-gray. Major minerals include quartz, microcline, plagioclase, and clinopyroxene. Biotite, orthopyroxene, and hornblende are minor minerals. Accessory minerals include sphene, zircon, apatite, and magnetite. Epidote and chlorite are secondary vein-filling minerals.
The western side of the exposure consists of 3 m of green cataclasite composed of pyroxene-biotite granite gneiss. The cataclasite contains foliation that exhibits northeast-striking dextral drag. The zone of cataclasite also contains a minor brittle fault filled with fault breccia that is oriented N28E 80NW. Horizontal slickenfibers are present on the northeast striking minor fault. In thin section, the cataclasite contains northeast-striking dextral pull-apart grains, minor northwest-striking sinistral faults, and offset grains exhibiting northeast-striking sinistral faulting. The cataclasite also contains both northwest-and northeast-dipping reverse faults. Movement sense is indicated by fibrous, stepped chlorite slickenfibers. The reverse faults average N53E 43NW and N47E 43SE.
The eastern side of the exposure consists of less deformed pyroxene-biotite granite gneiss. Sections of the eastern side of the exposure contain granite pegmatites but the majority of the exposure exhibits well developed gneissic foliation. The gneissic foliation is offset and dragged by minor northeast striking dextral and sinistral faults and minor northwest-striking dextral and sinistral faults. The minor faults represent early and late shear joints (Figs 4a and 4c). Offsets are often difficult to trace because of local shifts in the stress field during deformation. In thin section, the granite gneiss exhibits a cataclastic texture with pull-apart grains and offset grains similar to the cataclasite.

STOP 3. REVERSE AND STRIKE-SLIP STRUCTURES IN THE DEVONIAN skunnemunk CONGLOMERATE
This stop contains exposures of the same formation described at STOP 1 (Fig. 1b). The conglomerate exhibits both reverse and strike-slip kinematic indicators. The hill at this stop is a large syncline that is known as Bearfort Mountain. The walk is relatively steep and not recommended for individuals who have physical limitations (use common sense).
At the bottom of the hill and along the side of the hill are sinistral en echelon quartz vein arrays. The quartz veins range between 1 to 15 cm wide and 10 to 40 cm long. The exposures along the hill also contain northwest and southeast-dipping reverse faults. The reverse faults are similar to those at STOP l. Movement sense is indicated by quartz and chlorite fibrous, stepped slickenfibers. The shallowing of reverse faults away from the Reservoir Fault zone is exhibited. Average orientations of the reverse faults are N53E 54SE and N47E 52NW.
A small-scale keystone structure bounded by conjugate reverse faults (Fig. 4b) is located at the top of the hill. Reverse movement sense is indicated by slickenfibers and by offset quartz pebbles and quartz veins. Average orientations of the reverse faults are N52E 65NW and N47E 48SE. The acute angle between the conjugate reverse faults indicate a west-northwest to east-southeast maximum compression. This exposure also contains the late cross-cleavage produced by sinistral reactivation of the Reservoir Fault zone with an average orientation of N81E 89SE.

STOP 4. CATACLASITE IN THE GRENVILLE GNEISS AND TYPE II S-C MYLONITE IN THE SILURIAN GREEN POND CONGLOMERATE WITHIN THE RESERVOIR FAULT ZONE
Directly to the right of the parking area is a 15 m vertical face of cataclasite (Fig. 1b). The cataclasite is composed of pyroxene granite to alkali-feldspar granite gneiss. The pyroxene granite gneiss contains microcline, quartz, plagioclase, and clinopyroxene. Minor minerals include hornblende, orthopyroxene, and biotite. The gneiss also contains accessory sphene, apatite, magnetite, and zircon with secondary chlorite and epidote. The pyroxene granite gneiss is cut by granitic pegmatites. The pegmatites are coarse-grained and contain quartz, plagioclase, and microcline and are highly radioactive. A minor mineral is biotite and zircon is an accessory mineral. Secondary minerals include epidote, hematite, and monazite.
The northeast-striking foliation in the cataclasite exhibits dextral drag. In thin section, the cataclasite contains offset quartz and plagioclase grains, kinked plagioclase grains, and pull-apart textures in microcline grains (Fig. 3a). All of the microstructural features indicate northeast-striking dextral shearing. The dextral kinematic indicators are offset by later sinistral movement.
500 m south along the escarpment of cataclasite is a Type II S-C mylonite in the Green Pond conglomerate. The Green Pond conglomerate is a medium-grained quartz pebble conglomerate with a medium-grained sandy matrix and silica cement. The conglomerate contains thin interlayers of crossbedded sandstone. The shear zones in the conglomerate are not very extensive. The sheared conglomerate contains a semi-brittle mylonite with well defined C-planes subparallel to bedding and poorly defined S-planes (Fig. 2a). Northeast-striking dextral drag is exhibited by quartz ribbons along C-planes. In thin section, the sheared Green Pond conglomerate contains -Type porphyroclasts, conjugate deformation bands and lamellae (Fig. 2b), and shear bands. All of the microstructural features indicate northeast-striking dextral shearing.
2012: This stop is 0.4 miles from the last pull off, not 4.1 miles, but fits the rest of the data...

B2: THE STRATIGRAPHIC RELEVANCE AND ARCHAEOLOGICAL POTENTIAL OF THE CHERT BEARING CARBONATES WITHIN THE KITTATINNY SUPERGROUP
PHILIP C. LA PORTA
Queens College and Department of Earth and Environmental Sciences
C.U.N.Y.
All of the formations to be visited on this field trip are Cambro-Ordovician in age and were deposited in very shallow waters (shelf settings) (Figure 1). A few of the formations contain shaley members but are almost entirely composed of dolomites and lesser amounts of limestone.
The Cambrian formations are remarkably persistent both laterally and vertically and this leads to extensive facies continuities, covering distances as great at 50 to 100 miles (Read, 1985). The Lower Ordovician formations (capped by the Knox Unconformity; Sloss, 1963) have a more heterogeneous character, still with the same lateral persistence, but with considerably greater variations in facies composition.
The Cambrian cherts appear to be facies-controlled (porous oolitic layers, sandy layers, etc.) except for the top of the Allentown Formation. The upper Allentown appears to be a surface of unconformity, but is not marked by deep incisions, just shallow channel cuts. The zone of chertification follows this surface and occurs as a series of complex rubble zones, and silicification along joints.
The cherts within the Rickenbach Formation (Lower Ordovician) are facies controlled and are widely persistent fanning a distinct marker horizon. The lower member exhibits an intrastratal breccia, but there is no evidence of an associated unconformity. The Epler Formation contains chert which is facies-controlled, but the most obvious varieties of chert are associated with paleokarst features. Some of the paleokarst features were filled by argillite which has also suffered later silicification. The Epler Formation is overlain by the Ontelaunee, a fossiliferous carbonate, a good portion of which has been strongly dolomitized. Chert is ubiquitous to both members of the Ontelaunee Formation and the Harmonyvale (uppermost member) is strongly cut by erosion features. This erosion surface is very variable and in some places has incised all the way down into the Rickenbach Formation.
The great variety and volume of chert extant within the chert-bearing carbonates of the Kittatinny Supergroup has been known for some time (Markewicz, 1967). The use of chert beds as stratigraphic marker horizons or key beds was first implemented in this region by Markewicz (1967) and Markewicz and Dalton (1973). Their formation and member level subdivision (Fig. 1) will be used for the field trip. The chert appears to be restricted to specific units within members of the formations of the Kittatinny Supergroup. The chert-bearing facies are laterally persistent for substantial distances. (The host rock for the silica are often highly porous beds, unconformities and paleokarst fractures.) An extension of the chert stratigraphy has been the discovery, over the last two decades, of more than 200 small and large sites of prehistoric mining operations sites.
The chert stratigraphy is the focus of this field trip and has been specifically designed to also aid the archaeologist conducting provenance studies in the field.

B2: THE STRATIGRAPHIC RELEVANCE AND ARCHAEOLOGICAL POTENTIAL OF THE CHERT BEARING CARBONATES WITHIN THE KITTATINNY SUPERGROUP

STOP 1. PALEOKARST FEATURES AT DeKAY'S HAMLET.
The paleokarst features at DeKay's Hamlet are unique for several reasons. They are clearly visible on the Wawayanda topographic atlas sheet, and are outlined in Fig (3}. The single hole-like depressions are of great areal extent, and the likelihood of discovering more in the vicinity is very good. The infilling within the inverted depressions contains much more chert than is seen at other locations. The feature rests on the Upper member of the Allentown Formation. To the writer's knowledge, this represents the deepest penetration of the Knox-Beekmantown erosional event in this area.
Along Price Road, the Allentown Formation is poorly exposed and is visible as thickly bedded coarse grained blue dolomite with thin beds and wisps of black oolite chert. Capping the Upper Allentown is a chert sequence of variable thickness. Sawed slabs of chert from the Price Road outcrops have yielded both algal rich beds and slabs with a structureless form. The chert sequence capping the Allentown at DeKay's Hamlet may represent algal beds in some locations, while in others the chert may represent a silcrete (Khalaf, 1988}. Above this zone is the extensive rubble of the paleokarst feature. Chert clasts can be very large and the refitting of chert clasts, blocks, and beds within a single block of karst infilling dolomite is easily accomplished. The infilling between chert clasts and individual dolomite blocks is a very coarse grained buff dolomite.
The chert clasts appear to be representative of the Hope Member and the Crooked Swamp Dolomite Facies of the Rickenbach Formation. At a nearby location along Owen's Station Rd. in Wantage Township, a similar chert breccia contains the preserved remains of cystoid-like organisms.
In the surrounding valley, the outcrops of the Upper Member include a distinct intra-stratal breccia zone with siliceous infilling. The chert horizons may represent the remains of a vast doline system which penetrates the Allentown Formation and creates a plexus of breccia zones which may be genetically related to the vast subaerial feature being viewed at the first stop. This unique chert breccia and silicified infilling has not been encountered elsewhere in the valley, and recent field evidence suggests that in the Vernon Valley, the karstification may proceed down as far as the Limeport Member of the Allentown Formation. Virtually all of the farm fields in DeKay's Hamlet show exposed beds of the breccia and the laminated infilling described under the Upper Allentown Member. Similar laminated chert beds and brecciated zones are visible in the Big Springs Member of the Epler Formation but these do not bear the color characteristics of the Upper Allentown Member chert. Therefore it is logical to assume that the process of silicification and brecciation is similar in both cases.
The paleokarst feature appears to have provided quantities of chert to Archaic as well as Woodland Age groups of hunter-gatherers. The workshops and screes have a different character about them because the quarrying process is unlike other locations. Here, large angular chert clasts are worked free from the surrounding dolomite, instead of mining a single continuous bed of chert as at other locations. In addition, the archived collections from the area exhibit diagnostic projectile points whose overall morphologies are statistically different from culturally similar stone tool inventories from neighboring areas. This measurable difference in physical attributes may be linked to the individual artisan or to the physical properties and limitations of the chert. The writer feels the latter reason may be more important at this location.
The breccia zones described above crop out on nearby farm fields and all have been quarried for the intra-stratal breccias and silicious infillings.

STOP 2. THE PALEOKARST AT THE BEAVER RUN.
The traverse at Beaver Run begins in the Hope Member of the Rickenbach Formation, with the Leithsville and Allentown Formations behind you to the east (Fig. 4). Prominent within the Hope Member is a silicified intra-formational conglomerate, in which both rounded clasts as well as matrix have been silicified. This intra-formational conglomerate is also visible along the eastern edge of the Haven's Estate, and in the Richter Estate (see Fig. 4). The beds are inclined to the northwest and the intra-formational conglomerate has been interpreted by some to represent the base of an extensive paleokarst system. The paleokarst is first visible within the Branchville Member of the Epler Formation, where the dolomite is brecciated and re-cemented in-situ. When this occurs within the Big Springs and Lafayette Members of the Epler Formation, the solution crevices contain a laminated green argillic infilling, which occasionally bears euhedral pyrite. Farther up-section the topographically inverted karst infilling is visible to your right. The feature stands 180 feet in elevation above the roadside, and is prominent at the 700 ft. contour interval in Fig. 4. The eastern half of the feature is developed within the Epler Formation. The dislodged and overturned masses of dolomite in the eastern portion of the feature are derived frcxn the Big Springs and Lafayette Members.
Midway through the paleokarst feature, large blocks of chert bearing dolomite, derived from the Beaver Run Member are visible as a stack of disorientated re-cemented blocks. The slabs may represent the collapsed roof structure of the karst system. The paleokarst is best developed within the Lafayette Member. The evidence for karstification within the Epler Formation is visible along strike to the north into the Blair Estate Traverse and the Haven's Island #1 traverse, far greater than 6,000 ft. The feature continues to the south across Beaver Run Road more than 4,000 ft. to the Richter Prehistoric Chert Quarry along the Phillips Traverse (see Fig. 7).
The thickened Ontelaunee Formation section may be the result of faulting (see Fig. 4), and as you continue up-section, you encounter the Jacksonburg Formation (Ojb). From this point, proceed north along strike in the Beaver Run member. Here, along the western edge of the traverse are a splay of intrusive dikes, thought to be upper-Lower Ordovician. Approximately 1,000 feet north, along strike and southeast of the Dagmar Dale Estate, is a prehistoric chert quarry developed within the Beaver Run Member. This quarry and associated scree is typical of those developed within the Beaver Run Member. There is an enormous quantity of broken chert, all representing the earliest stages of the lithic reduction process.
If time and interest exist, traverse downsection on the Blair Estate, of which you are presently on the western edge. Visible will be paleokarst within the Epler formation, chert quarries within the chert breccia zones of the Lower member of the Rickenbach Formation, and a series of convex upwards silicified algal beds present in the Upper Allentown Formation. The algal structures are present on the Haven's Estate and elsewhere within the Hamburg Quadrangle and may represent a distinct marker horizon.

STOP 3. THE PREHISTORIC QUARRIES AT BEAVER RUN CREEK.
The traverse begins on the south side of Pond School Road 700 ft. east of the road, in the Lower member of the Rickenbach Formation. The rubble zone marking the unconformity is at the top of the Upper Allentown Member. The chert breccia of the Lower Rickenbach is present here (Fig. 5). Above the chert breccia is the lower chert horizon of the Hope Member. Proceed up section into the Branchvile member of the Epler Formation. Visible from this point is yet another type of paleokarst infilling. Here are large cemented masses of a very coarse grained dolomite. Throughout the dolomite are clasts of lavender and blue chert. The clasts represent the broken and disrupted chert bearing beds of all three members of the Epler Formation. Two hundred feet to the south is a series of round-like structures which represent a prehistoric quarry operation within the Branchville Member. The chert present is translucent white·with lavender brecciated masses. This breccia is tightly welded., and the quarry is represented by buried tailings.
Across School Pond Road to the west 300 feet is the prehistoric quarry at Beaver Run. This is an excellent location because the quarry has been acted upon by erosion and the prehistoric workings are visible.
The traverse begins 200 feet upsection in the Beaver Run member of the Ontelaunee Formation. A massive black chert zone is present in the Beaver Run member. Evidence of the reduction process is to be found at the quarry face. Many of the quartzite boulders and cobbles lying in the rubble represent the broken remains of discarded hammer and anvil stones. Approximately 75 feet above the thick chert sequence is the base of the Harmonyvale Member. There are a great number of conical depressions along strike in the many chert beds of the Harmonyvale Member. This pattern may represent the differential weathering of the solution cleavage within the Harmonyvale Member.
Both members of the Ontelaunee Formation are included in this quarry, and the workings and prospects extend an area of 450 feet by 300 feet. In this quarry, the Harmonyvale Member appears to be the preferred ore, as most of the deeper prospects are developed within this member. There is more archaeological visibility within the lower Beaver Run member, than in the Harmonyvale Member. The Beaver Run chert is usually conspicuous on the landscape, forming benches and topographic high areas. The prehistoric workings are usually extensive and the quarries can be developed continuously along strike. The tough ash-gray dolomite of the Harmonyvale Member, oftentimes caps the crests of hillsides and is covered by vegetation. Prehistoric workings within the Harmonyvale member are much less visible to the observer. Usually, a single light blue chert bed will be worked continuously along strike for several hundred feet as at this 1ocation. Because Harmonyvale chert occurs as thinner beds, the conical pits and workings along strike exhibit less visibility. Chert beds within the Beaver Run member can attain thicknesses of 8 or 10 feet, which render the quarries conspicuous. The writer feels that when both members are present in one quarry complex, the Beaver Run Member may be a second choice of lesser grade ore. The more highly sought after ore is the light blue chert of the Hannonyvale Member. This seems to be substantiated through the examination of archived collections.
Great quantities of quartzite hammerstones are present at this site. One large pounding stone or anvil near the Beaver Run member weighs more than 100 pounds. A collection of very diagnostic hammerstones was made at this quarry. These are always fashioned from quartzite, perfectly round and flat along their top sides, much like a wheel. Many instruments of this kind have been collected as well as hammerstones which appear to approach this diagnostic form. The hammerstones in the quarry represent the continuum of mining instruments, from expedient tools to instruments which are midway or at some stage of refinement towards being diagnostic. The final stage of processing appears to be represented by the spherical form with the flattened edges, or achieving the ideal pre-determined form.
Most of the quarry workings represent the initial reduction process. Chert from the quarry is found as unprepared cores, prepared cores, and diagnostic tools throughout the valley. It appears that much of the reduction process took place away from the quarry site.

STOP 4. THE HARMONYVALE TRAVERSE.
The Harmonyvale traverse begins at the base of the Branchville member of the Epler Formation (Fig. 6). The ravine to your east is occupied by the Hope member of the Rickenbach Formation, and the eastern edge of the summit is occupied by the Crooked Swamp Facies. Present is the sugary blue dolomite, which has a sulfurous odor on freshly broken surfaces, clots of varied-colored black and blue mottled chert, and silicified algal structures.
Proceeding up-section, the base of the Branchville member exhibits discontinuous black chert beds, up to 8 or 10 inches thick. Small chert outcrop quarries are present within this horizon. Up-section and to the south, one encounters the white chert of the Branchville member. The outcrops are littered with prehistoric workshop debitage and 30-40 small outcrop quarries exist along strike to the south in this member.
The Big Springs member crops out within the woodlot near the eastern shore of the pond. The lower unit contains a unique variety of chert which is maroon and white, and slabby. It represents a silicified shale unit which is stratigraphically similar to the maroon shales within the Upper Branchville member, at Haven's Island #4 Traverse. Above this unit are a series of jade green and white chert beds. The green chert beds may represent the silicified equivalent of the argillaceous karst infilling ubiquitous to the Big Springs Member. The white chert achieves an acme in form along this series of outcrops, where it is highly translucent, milky to waxy white to gray, highly lustrous, and occurs as both beds and clots. The laminated porcelain-like gray chert is also present at these outcrops.
Close inspection will reveal prehistoric outcrop quarries, and a large quarry is buried under tailings at this location. The dolomite and chert blocks and rubble are part of the quarry tailings. Quartzite hammerstones, and chert debitage are abundant near the surface. Proceed along strike to the southeastern edge of the pond and back down-section 300 feet to the base of the Branchville Member, and the location of yet another prehistoric quarry. The principal ore here is the white chert and the porcelain-like chert. A small surface clearing has yielded hundreds of hammers tones and countless chert flakes. This series of quarries clearly illustrates the difficulty encountered when attempting to locate prehistoric chert mines. The ancient mining operations are usually buried in old tailings and fallen vegetation. This fact has also served to preserve their potential wealth of knowledge.
Now traverse up-section through the Big Springs and Lafayette members across the southern edge of the pond, and into the base of the Beaver Run member. Approximately 100 feet up-section occur the first series of dolomite and associated chert beds. The chert is vuggy, rugose and occurs in concentration as discontinuous swells which create topography to the south along strike. Each of these swells marks the location of very small chert outcrop quarries. Up-section is a second zone of chert which occurs as a series of beds which pinch and swell. The chert is homogeneous vitreous, and black, whereas the associated dolomite beds are thick and billowy. These chert beds are extensively quarried along the southwestern portion of the pond. The base of the steep ledge created by the resistant chert beds is covered with broken dolomite and chert beds, which have been pried from their ledges.
Transitional into the Harmonyvale Member is a dark and light blue mottled chert bed which is laterally continuous and eventually grades into a dolomite bed. The dolomite here is resistant, crosshatched, weathers to a white color and marks the lower Harmonyvale Member. Prehistoric mining activity is extensive here, but the precipitous climb and lush vegetation hinder close inspection.
Traverse along strike in the Beaver Run Member, passing the swells of rugose chert, and continue 1,500 feet to the 700 feet contour interval and a large scree developed along one bed of Harmonyvale chert. The workings in this light blue bed are continuous for 90 feet Below this scree is a 1arge quarry face developed in the upper unit of the Beaver Run Member. Inspect the proliferation of chert. To the immediate west lies the Jacksonburg Formation. Turn south. and traverse to the pond along strike in the Epler Formation. End of the Traverse.

STOP 5. THE RICHTER AND PHILLIPS ESTATES TRAVERSE.
The traverse begins in the rubble zone of the Upper Allentown member. Proceed up section through a thick chert breccia zone of the Lower Member of the Rickenbach Formation (Fig. 7). The ravine to your west is underlain by the Hope Member of the Rickenbach Formation and a distinct chert horizon is visible to the south along strike. The bedding dips to the northwest (see Fig. 7). Traverse through the open field which is underlain by the Crooked Swamp Facies, further south along strike. The step cliff overlooking the ice pond is composed of the Hope Member and Crooked Swamp Facies. The distinct chert horizon is visible in this ravine. The wall of the cliff face contains a partially silicified intra-formational conglomerate. Above this is a zone of sugary coarse grained blue dolomite containing wisps, beds and clots of a blue-gray translucent chert. This outcrop bears great resemblance to the Crooked Swamp Facies. The crest of this hill contains the Branchville member of the Epler Formation. The characteristic lavender and white brecciated chert zone is at the base of the member. Small prehistoric outcrop quarries are abundant along strike to the north. The ravine is occupied by the Lafayette Member and is much similar to the Lafayette Member ravine at Harmonyvale. You will cross this ravine to a hillside underlain by the Beaver Run Member of the Ontelaunee Formation. This is the Richter Estate.
The Beaver Run Member is covered by vegetation at this location. If you traverse north towards Beaver Run Road. you will cross over into the Harmonyvale Member, when the stratigraphic section thickens. Here are a number of small outcrop quarries and screes developed in the Harmonyvale Member. This light blue chert is very similar to the chert exposed in the quarry at the Phillips Estate, just to your west, and very similar to the chert at the Harmonyvale and the Beaver Run Quarries. The west facing slope is underlain by very fossiliferous Jacksonburg limestone. As you cross the Jacksonburg, you pass the location of a proposed fault, (see Fig. 7) and thereby re-enter the Beaver Run Member. Here the Beaver Run contains the upper chert-bearing unit, and a small prehistoric outcrop quarry and scree is present along the summit of the hill.
Passing westward, down the steep west-facing slope and into the Harmonyvale Member, you encounter a unique prehistoric quarry in the Harmonyvale Member. Vegetation-covered mounds of quarry tailings are present, along with the characteristic quartzite hammerstones. The unique feature of this quarry is what appears to be a rock-cut shaft which is about 10' x 10' and filled with tailings. A 6 inch thick light blue chert bed is inclined into the shaft at an inclination of 47° NW. The writer does not know how deep the shaft is or how extensive are the workings. As in the instance of the other quarries, all the workings are deeply buried and only a thin veneer of cultural debitage marks the locations of the ancient prospects. Erosion along steep slopes has exposed the workings and created a window into the past. Similar workings are present throughout this ravine which is to the north on the Phillips Estate. Just to your west is the Jacksonburg Formation repeated after the fault, and the Bushkill Member of the Martinsburg Formation (Omb) which comprises the western hillside and the termination of the traverse.

STOP 6. THE CHERT QUARRY ALONG THE PAULINS KILL.
The traverse along the Paulins Kill was suggested by Don Monteverde and Greg Herman of the New Jersey Geological Survey. They have noted large concentrations of chert within the Ontelaunee Formation. The prehistoric chert quarry on this traverse was located within the first day of research in the area.
The quarry is developed within the Beaver Run member of the Ontelaunee Formation, and has a length greater than 200 feet (Fig. 8). The chert beds pinch out to the north and south. To the writer's knowledge, the Harmonyvale Member is not present along this traverse. A distinct rubble zone occurs at the top of the section. and marks the incision of the Knox-Beekmantown Unconformity which removed the Harmonyvale Member at this location. The Jacksonburg Formation (Ojb) lies to our east under Paulins Kill Lake. The steep rise to your east is comprised of the Beaver Run Member and across Dove Island Road to your west lies the Epler and Richenbach Formations. If the stratigraphic formations contacts are interpreted correctly, the chert quarry is developed along the eastern 1imb of an antiform.
The series of black. and gray chert beds have been extensively worked. The gently inclined beds allowed easy access to the chert. This factor often determines to what degree the chert beds will be exploited. Tailings from the initial stages of reduction are abundant and this is one of the few quarries where structure and erosion are combined for excellent viewing. The chert beds are thick and homogeneous, with well-spaced fractures, creating a valuable ore of the black chert.

B3: ANCIENT LAND SURFACES IN AND AROUND THE GREEN POND OUTLIER, A DEVONIAN CORAL REEF, AND "TACONIAN ISLANDS" REVISITED.
ROBERT M. FINKS AND MICHAEL P. RAFFONI
Department of Geology, Queens College (CUNY)
Flushing,NY 11367
Some twenty years ago, at the 1968 NYSGA meeting, the senior author led a trip entitled "Taconian Islands and the Shores of Appalachia" (Finks, 1968). Having acquired a few new thoughts in the meantime, and a new generation of NYSGA members having come on the scene, it seems appropriate to revisit some of these localities on the way to a splendid Devonian coral reef studied by the junior author.
The sites visited are intended to stimulate further research rather than to present definitive answers. It is hoped that discussion will ensue, both on the trip and later. Much of the trip involves observation of fluvial bed-loads of various ages, and discussion of what they tell us.

B3: ANCIENT LAND SURFACES IN AND AROUND THE GREEN POND OUTLIER, A DEVONIAN CORAL REEF, AND "TACONIAN ISLANDS" REVISITED.

Anticline in Martinsburg Fm.
Anticline in Martinsburg Formation (Ordovician) on left. Zone 13 (possibly Zone 14) graptolites were collected here by Alejandro Vargas and identified by W.B.N. Berry (Vargas, 1976, p. 32 and fig. SA). Distal turbidites can be seen here.

Martinsburg Slate on both sides of the road.

Martinsburg Slate on both sides of the road again.

Klippe of Precambrian gneiss on right, forming hill.

Klippe of Precambrian gneiss on left
Klippe of Precambrian gneiss on left, in thrust contact with underlying Cambro-Ordovician dolomite. The thrust plane and accompanying fault breccias can be seen.

BONUS STOP. Museum Village Klippe
Walk into woods on left (south) side of road downhill toward NY 17, crossing the old, low stone wall left of the barbed wire. At highway level the thrust plane is exposed, dipping about 30° SE, with garnet-gneiss above and white-weathering dolomite below. Immediately above the fault plane you may collect samples of gneiss mylonite breccia, and immediately below it, tectonic breccia of dolomite.

Western border fault
The western border fault of the skunnemunk Outlier crosses approximately here, shown on the 1971 NY State Map as a small offset of the main fault at this point. (Fisher, Isachsen and Rickard, 1971.)

Bellvale Sandstone on left, dipping SE. (Mid-Devonian)

Axis of skunnemunk Syncline plunging NE.
Horizontal pebble beds of Bellvale Sandstone on left. Between here and .4 miles ahead is a 2,000-foot complete section of the Bellvale Sandstone (measured section in Finks, 1968) from submarine prodelta silts .4 miles ahead to subaerial piedmont conglomerates at here. It is a part of the Catskill Delta. The beds dip NW on the east limb of the skunnemunk Syncline.

Basal beds of Bellvale Sandstone, dipping steeply NW.

Ramapo Mountains ahead and to your left
Main mass of Ramapo Mountains (Hudson Highlands) are ahead (Precambrian of Reading Prong) and to your left as you swing south. You are in a valley on Cambro-Ordovician dolomitic limestones. This is also part of the Green Pond - skunnemunk Outlier, although the NY State Map has a structural discontinuity (normal fault) between these rocks and the Siluro-Devonian just passed through (Fisher, Isachsen and Rickard, 1971).

Outcrop of Cambro-Ordovician limestone on left.

Outcrop of Cambro-Ordovician limestone also on left.

Greenwood Furnace on left.
This smelter served the small magnetite mines in this vicinity during the 19th Century. The ore is from the Precambrian rocks.

Town of Tuxedo Park, where the Tuxedo jacket was invented.

Precambrian gneiss outcrop on left.

Crossing Ramapo Fault into Mesozoic Basin
Crossing Ramapo Fault into Mesozoic Basin, a rift-valley formed during the opening of the Atlantic Ocean. The Green Pond-skunnemunk Outlier has a similar structure and may be a Mesozoic basin in which no Mesozoic rocks were preserved. (Or a Siluro-Devonian extensional basin?)

Old stone house on right. Historic marker.

Good view of Ramapo fault-line scarp on right.

Crossing Orange Mountain Basalt (Lower Jurassic).

Outcrops of Orange Mountain Basalt on left.

Another basalt outcrop on left.

STOP 1. OAKLAND. JURASSIC FANGLOMERATE BENEATH THE PREAKNESS BASALT.
The most accessible outcrops are on the south side of the diner parking lot on the east side of US 202. Look for the boulders of vesicular basalt. Search for gneiss boulders. Some Paleozoic formations to look for are: white-to-buff-weathering Cambro-Ordovician dolomites, the purple with white quartz Green Pond Conglomerate, the red with white quartz and red quartzite Skunnemunk Conglomerate, the subgreywacke Bellvale Sandstone. Note their proportions.

Outcrop of Preakness Basalt on left.

This is Stop 2. Do not stop here but proceed to Noyias Road.

STOP 2. POMPTON LAKES. JURASSIC FANGLOMERATE BENEATH THE HOOK MOUNTAIN BASALT.
Park off road next to pumping station. Walk back to outcrop on east side of US 202. LOOK BOTH WAYS WHEN CROSSING ROUTE 202. YOU ARE ON A CURVE AND A HILL. VISIBILITY IS LIMITED. WALK FACING TRAFFIC AND STAY OFF THE ROADWAY.
Note the large boulder of Green Pond Conglomerate near the south end of the outcrop, and the many boulders of whitish-weathering Cambro-Ordovician dolomite. Note also the interbeds of finer sand and shale. How do the proportions of lithologies among the clasts compare with those of the preceding stop?

Outcrop of Hook Mountain Basalt on left.
The outcrop crosses the bed of the Ramapo River on the right, on top of which is a dam and waterfall.

Cross Ramapo River.

Crossing Wanaque River.

STOP 3. RIVERDALE. ANNSVILLE PHYLLITE (ORDOVICIAN) AND BED-LOAD OF THE PEQUANNOCK RIVER.
Descend carefully under the bridge and walk to the south side of the east abutment. There is also a path to this point from the south side of Hamburg Turnpike. CAREFUL CROSSING ROAD. The outcrop of the Annsville Phyllite is exposed here. PLEASE DO NOT HAMMER ON THIS RARE OUTCROP! THERE ARE PLENTY OF LOOSE PIECES LYING ABOUT. Another small outcrop lies upstream of the bridge in the channel and on the west bank.
Unless the river is in flood, a large sample of the Pequannock bed-load is exposed beneath and downstream of the bridge. Look for imbricated cobbles. See how many different Precambrian lithologies you can find. Green Pond Conglomerate cobbles are common. Can you find any Cambro-Ordovician dolomites? This river crosses the Green Pond outcrop about ten miles upstream, but much closer glacial moraines may be the source of most of the cobbles.

There is a quarry in Precambrian granite visible ahead.

Washington's Headquarters on left.

Crossing Ramapo Fault.
Road climbs hill on Precambrian with extensive cuts exposed in ramps for I-287. A gravel pit was formerly present to the left (south) in a delta built into Glacial Lake Passaic. Moraines on left about a half mile ahead.

Outcrops of Precambrian on right, Pequannock River valley on left.

Kanouse Mountain ahead, made of Green Pond Conglomerate on Precambrian.

You are paralleling Kanouse Mountain.

Bend in road. Hill of Precambrian ahead.

STOP 4. GOULD QUARRY.
PRECAMBRIAN GNEISS, HARDYSTON SANDSTONE AND LEITHSVILLE DOLOMITE (LOWER CAMBRIAN) , BASAL GREEN POND CONGLOMERATE (SILURIAN) IN KARSTIC POCKETS.
Outcrops at entrance to the road are Precambrian gneiss. Continue uphill on this road to the SW. Where the road bends to the left (south) continue straight ahead into the woods. You will soon reach a small swale. The lower Hardyston Sandstone underlies this swale. As you face SW, the hill on your left is Precambrian gneiss and the low ridge on the right exposes ledges of the upper part of the Hardyston Sandstone and the base of the Leithsville (or Stissing) Dolomite dipping NW. Walcott (1893) reported the trilobite Olenellus from the same beds a mile or so north, proving their Lower Cambrian age (and for us, their position on the Laurentian Plate). Follow this ridge a short ways to its southern end, where there is a small depression and cross-valley in the ridge. In the depression, against the ledges to the left, is a small pocket of conglomerate in the basal Leithsville Dolomite. (It may be covered by leaves.) This is a karstic cavity filled with the Silurian Green Pond Conglomerate which has infiltrated from above. A thin red shale lines this pocket. Walk to the top of the Leithsville ridge at this point through the small notch and descend its west side. Immediately to the right you will see a small patch of conglomerate on top of the steeply northwestward dipping beds of the Leithsville Dolomite. If you examine the dip-slope below it you can see a narrow extension of this patch apparently filling a fissure in the Leithsville. This must have been the entrance for the gravel into the pocket represented by the patch. PLEASE DO NOT HAMM£R ON THIS RARE OUTCROP! IT IS THE ONLY RELIC OF THE KARSTIC INFILLING. PLEASE PRESERVE IT FOR POSTERITY. This outcrop was illustrated by Rodgers (1971, p. 1160, fig. 9B). In the valley to the west is a small outcrop of the Green Pond Conglomerate just west of a small brook. The main mass of Kanouse Mountain, composed of the conglomerate, lies beyond. If you have time, note the ruins of the old lime kiln, north of the quarry, with its partly melted walls of stone blocks. The Leithsville was quarried here for lime. This tree-filled hollow was once an active quarry. The geologic relations here are illustrated in Kümmel and Weller (1902, figure 1).

STOP 5. NEWFOUNDLAND. GREEN POND CONGLOMERATE (SILURIAN) AND PRECAMBRIAN GNEISS.
The parking area is a loop of old Route 23 and is the original width of the two-way road. Note the historical marker with original relics of local iron smelting. To the south of NJ 23 is Charlotteburg Reservoir. Copperas Mountain to its right (west) comprises the extension of the Green Pond outcrop on the south of the Pequannock watergap. Seen in the distance to the west-southwest, are the ridges of Green Pond Mountain and Browns Mountain, also composed of Green Pond Conglomerate on Precambrian, repeated by folding and faulting.
The nearest ledges north of the parking area show well the steep westward dip and the fining-upward cycles in the Lower Conglomerate Member of the Green Pond Formation. Look for colored chert clasts (red, green, black) in the conglomerate layers. Many show weathering rinds. Follow the base of the cliff uphill to the east (right). A short distance up is a good place to see the cross-bedding. Note the consistent westward dip of the cross-laminations, indicating a westward current.
Continue upward along the base of the cliff and pick up a trail which heads uphill into the woods parallel to the base of the cliff but some distance from it. Keep on this trail in a northeastward direction. After several hundred feet you will come upon ledges of Precambrian gneiss. They are about 50 feet from the base of the cliff, the intervening area being strewn with large talus blocks of the conglomerate. The actual unconformity is not exposed here but it is clear that the conglomerate must rest directly on the gneiss.
When you return via the same trail you will see on the right (west) just above the ledges next to the parking area, beds of the higher non-conglomeratic part of the Green Pond Formation ("Upper Quartzite Member" of Finks, 1968). You can climb up to them if you have rubber-soled shoes or hiking boots (STAY AWAY FROM THE CLIFF EDGE TO THE LEFT) and observe the banded tongues (Liesegang rings) of hematite, showing former groundwater flow to the left (southwest) when the quartzite still had porosity.

Drag folds in Upper Quartzite Member of Green Pond Conglomerate.

Small outcrop of Longwood red shale (Upper Silurian) on right.

Type locality of the Kanouse Sandstone (Lower Devonian) in the village of Newfoundland to the right.

Outcrops of Precambrian.
We have just crossed the normal fault bounding the Green Pond-skunnemunk Outlier on the northwest. Oak Ridge Reservoir on left. The fault-line scarp bounds the reservoir on the west. This is called the Reservoir Fault (see Malizzi and Gates in this guidebook).

Franklin Lake on left. Source of the Wallkill River.

Outcrop of Cambro-Ordovician limestone on right.

Old Buckwheat Mine dump and Franklin Mineral Museum on right.
Old Buckwheat Mine dump (zinc mine in Precambrian Franklin Marble; type locality for Franklinite) and Franklin Mineral Museum on right.

Crossing Wallkill River.
This river flows northeast to join the Hudson River at Kingston, following the Great Valley on the Cambro-Ordovician outcrop belt. Water from Franklin Lake flows 75 miles northeast, then another 100 miles south before it reaches the sea.

Wildcat Road on left.
0.5 mile down this road is an exposure of the Precambrian-Lower Cambrian unconformity (described in Finks, 1968). The first archaeocyathids from New Jersey were found here in the basal Leithsville Dolomite by Frank Markiewicz on the 1968 NYSGA field trip.

Outcrop of Cambro-Ordovician Limestone on left.

Outcrops of Cambro-Ordovician limestone on left.

Outcrops of Martinsburg Slate on right.

Culver Lake on right.
Ahead is Kittatinny Mountain, held up by the Silurian Shawangunk Conglomerate.

Outcrop of New Scotland Limestone (Lower Devonian) on right.

STOP 6. COEYMANS LIMESTONE REEF LOWER DEVONIAN).
Park off road on right. Mile marker 1. Enter woods-trail ahead on left, opposite outcrop of pre-reef limestone on right.
Approach the reef by the trail which leads toward the high southeast cliff and attain the top by climbing the slope to the right (east) of it. Here you are at the supposed back-slope area dominated by massive Thamnopora. A good outcrop to start with, showing most of the coral species, is just west of the large glacial erratic boulder of shale. From here one may walk along the edge of the high cliff to the west and then north. The reef-ridge area of strong orientations, with dominant branching Thamnopora, solitary rugosa, and domal stromatoporoids, is best exposed at about halfway along the northwest face. (Compare Figures 5, 7, and 8.) From here one may walk south along a series of outcrops toward the highest part of the hill, seeing the back-reef lagoon facies and finally reaching the back-slope area at the top of the hill. From here one may walk northeast, past the old stone wall on the right (east) to a fine outcrop at the northeast tip of the reef, with silicified oriented branching Thamnopora well displayed, again part of the reef-ridge. (Compare Figure 10.) A walk back along the base of the northwest-facing cliff paralleling the reef-ridge will show some calcarenite channels in cross section (or grooves of a spur-and-groove system) near the northeast end, some fine stromatoporoid colonies in vertical section about half-way along, and the pre-reef calcarenites at the southwest end. Note that the matrix of the main part of the reef is mostly micrite.

B4: THE WATCHUNG BASALTS OF NORTHERN NEW JERSEY
JOHN H. PUFFER
Geology Department
Newark, New Jersey 07102
This field trip through the northern end of the Watchung Mountains of New Jersey will include six good exposures of quartz tholeiitic basalt. The Watchung basalt flows of the Mesozoic Newark Basin are exposed as three northeast/southwest trending ridges. The three basalt units dip to the west at about 15 degrees and are known as the Orange Mountain, Preakness, and Hook Mountain Basalts (Fig. 1).
The lower contact of the first flow unit of the Orange Mountain Basalt with the underlying Passaic Formation will be seen at Stop 2. The three flow units of the Orange Mountain Basalt are locally separated from each other by thin layers of sediment and comprise an aggregate thickness averaging 183 m (Faust, 1975). The upper flow is characteristically pillowed and amygdaloidal, whereas the lower two flows typically display well-developed columnar joints (lower colonnade and entablature).
Each of the three flow units of the Preakness Basalt are geochemically distinct, and each will be visited during the field trip. The massive, very coarse grained lower flow of the Preakness will be seen at Stop 3, the second flow together with a thin layer of sediment separating it from the first flow will be seen at Stop 4, and the second and third flows separated by another thin layer of sediment will be seen at Stop 5. The aggregate thickness of, the three Preakness flows averages 215 m (Olsen, 1980).
The lower contact of the Hook Mountain Basalt with the underlying Towaco Formation will be seen at Stop 6. The Hook Mountain Basalt extruded about 550,000 years after the extrusion of the Orange Mountain Basalt (Olsen and Fedosh, 1988) and consists of at least two flows with an aggregate thickness of 91 m (Faust, 1975).
The hydrous mineral assemblages that accumulated in the vesicles and vugs between pillows of Watchung Basalt, presumably mixtures of carbonates, clays and alteration products, have responded to low temperature burial metamorphic effects. The resulting zeolite facies assemblage includes some very well developed crystal aggregates of stilbite, heulandite, chabazite, and datolite typically precipitated with calcite, quartz, prehnite, and sulfides (principally chalcopyrite and chalcocite).

B4: THE WATCHUNG BASALTS OF NORTHERN NEW JERSEY

STOP 1. LADENTOWN BASALT
The closely-spaced curved cooling columns displayed by the Ladentown basalt along us 202 contrast with the thick massive columns typical of the Palisades sill that underlies the basalt and was probably its source of magma. The basalt exposed at this locality is fine grained, contains large plagioclase phenocrysts, and is slightly vesicular. Chemical analysis of the Ladentown Basalt (Puffer and others, 1982) compare closely with the fractionated interior (Walker's (1969) second magma pulse of the Palisades sill). The Ladentown Basalt, appears to have extruded onto sediments of the Passaic Formation, perhaps forced to the surface by the injection of a second magma pulse within the Palisades sill. This occurred before the Feltville Formation was deposited, and before the Preakness Basalt was extruded. A physical connection between the Ladentown flow and the western end of the Palisades sill at Mount Ivy is indicated by magnetic and gravity data (Kostsomitis, 1980; Kodama, 1983). However, this connection is not seen at the surface.
Good exposures of coarse boulder conglomerate are located another 0.4 mi. south along US 202. The coarse clast size of the sediment coincides with their close proximity to the western border fault in the valley running parallel to US 202. Note the distinct change in topography on the opposite side of the border fault where Precambrian gneisses are the dominant lithology.

Fanglomerate and Reading Prong
Coarse grained fanglomerate exposed on the left and the Precambrian Highlands of the Reading Prong exposed west of the Ramapo fault valley on the right.

STOP 2. PREAKNESS BASALT AT HIGH MOUNTAIN, NORTH HALEDON
High Mountain is the highest point (970ft; 296m.) in the Preakeness Mountain chain. The upper portion of the hiking or jeep trail to the top of High Mountain cuts through closely spaced columnar-jointed basalt typical of the entablature of the Preakness Basalt. At the top of the mountain is a beautiful alpine meadow that on a clear day affords a spectacular view of most of northern New Jersey. The basalt exposed in the meadow is very coarse-grained; it is typical of the interior of the first flow of the Preakness Basalt and resembles diabase.
The view to the southeast includes the New York City skyline in the background behind the ridge formed by the Palisades sill. (A copy of 1981 Paterson 7 1/2-minute Quadrangle is recommended). The city of Paterson is in the foreground where the Passaic River cuts through the First Watchung Mountain ridge formed by the westward dipping Orange Mountain Basalt. The New Street traprock quarries and Garret Mountain are clearly visible just north of Paterson. The view directly to the south includes the city of Newark in the distant background on the far side of the First Watchung Mountain, Montclair State College southeast of Paterson, and Paterson State College in the foreground. The view to the southwest includes the Precambrian New Jersey Highlands province west of the Ramapo Fault scarp in the background and the curved "inverted S" shaped Hook Mountain ridge formed by the Hook Mountain Basalt in the foreground.

STOP 3. ORANGE MOUNTAIN BASALT AT PASSAIC FALLS
An excellent exposure of Orange Mountain Basalt is located here in the park above Passaic Falls. Observe the columnar jointing in the basalt and some large convex upward, or half-moon vesicles that typically occur near flow-tops. Carefully climb into the narrow notch in the basalt eroded along the strike-slip fault for a closer inspection of the basalt. Most of the slickensides have been eroded away but a few still remain.
Cross the footbridge, or if blocked, walk down Spruce Street to the statue of Alexander Hamilton. At the exposure along the north edge of the parking lot near the statue of Alexander Hamilton, the lower contact of the Orange Mountain Basalt with the underlying Passaic Formation is seen. Southwest plunging pipe-amygdules and vesicles are exposed in the basalt near the contact. These vesicles occur entirely within the basalt above the basal contact. From the statue of Alexander Hamilton observe the vertical strike-slip fault planes through the lower flow unit of the Orange Mountain Basalt and the contact between the lower colonnade and the overlying entablature. The "S.U.M." over the door of the historic building near the river at the base of the view area stands for "Society of Useful Manufactures," an organization founded in 1789 to promote local trade.
From the falls, walk south along Spruce Street, cross McBride Avenue and continue one-half block to the Paterson Museum. Some of the best examples of the secondary minerals found in the Paterson area trap-rock quarries are on display at the museum.

STOP 4. PREAKNESS PILLOW BASALT, TOTOWA
The lower portion of a Preakness Mountain Basalt flow unit, the second of three, is exposed along the west side of Claremont Avenue. The base of the flow is a subaqueous flow lobe containing ellipsoidal pillows and pahoehoe toes. Secondary mineralization includes calcite, quartz, and minor heulandite in small stretched amygdules. The pillowed base of the flow rests on a thin layer of red siltstone exposed (depending on the amount of refuse present) at road level. The flow grades upward into massive columnar basalt. Further north on Claremont Avenue the upper part of the flow, in contrast to the bottom is not pillowed and contains large spherical amygdules mineralized with prehnite and pectolite.

STOP 5. UPPER (LOW-TI) FLOW OF PREAKNESS BASALT, NORTH CALDWELL
The middle and upper flows of the Preakness Basalt are exposed here together with a layer of red siltstone that was deposited between the two flows. The middle flow is well exposed along the banks of Green Pond (sample site P39, Fig. 1) and can be examined by carefully walking down the slope near the bridge. Be careful of the poison ivy. The middle flow is greatly enriched in incompatible elements compared to the upper high-Ti or HTO flow of the Preakness (Table 1).
The upper flow can be examined along the road-cut just south of the bridge (Sample site P40, Fig 1). It is exposed above the thin red siltstone layer along the road. Good dinosaur footprints were found in this siltstone by Chris Laskovich. Columnar jointing is reasonably well displayed at this stop but both flows are other-wise quite massive with little evidence of secondary mineralization.

STOP 6. HOOK MOUNTAIN BASALT, ROSELAND
This Hook Mountain exposure displays columnar joints, but a well-defined Tomkeieff (1940) sequence is not apparent. An extensively altered volcano-clastic layer is exposed near the base of the Hook Mountain Basalt. In addition, some bleaching and evidence of low-grade thermal metamorphism is seen at the lower contact.
In contrast to the Orange Mountain (Stop 2) and Preakness (Stop 3) Basalts, the Hook Mountain Basalt is relatively enriched in amygdules and vesicles. Prehnite is abundant at this locality and is easily collected, particularly near the north end of the exposure.

B5: PLEISTOCENE GEOLOGY OF THE EASTERN, LOWER HUDSON VALLEY, NEW YORK
Les Sirkin
Garden City, NY 11530
Room 3140
G. Gordon Connally
12 University Avenue
Buffalo, NY 14214
A preliminary understanding of the style of glacial retreat, in the eastern lower Hudson Valley, has been gained through mapping the surficial deposits between the Long Island-Staten Island end moraines and the Hudson Highlands. The present model of late Pleistocene glaciation for the region includes 1) a lobate ice front, 2) two distinct glaciations separated by a warm interval, and 3) final deglaciation with the sequential development of recessional moraines at some ice margins and extensive preglacial lake and valley fill deposits. This model is used in conjunction with field evidence to reconstruct the glacial history of the region. This field guide provides the basic framework for the glacial history and illustrates typical deposits and morphologic features. This article complements that of Connally, Sirkin, and Cadwell (this volume). For convenience, certain sections and descriptions are not repeated in both articles, but are cross referenced.

B5: PLEISTOCENE GEOLOGY OF THE EASTERN, LOWER HUDSON VALLEY, NEW YORK

STOP 1. CROTON POINT PARK.
Walk westward along the beach about 0.5 mi. to exposures of till and clay beds. Discussion will center on the evidence for the Croton Moraine and the Croton Point Delta (see Figure 1 in text). Note the lithologies of the boulders.

STOP 2. PEEKSKILL HOLLOW CREEK: CLAY BEDS.
Park at the entrance to the new railroad station construction site. Walk northeastward to stream bed. Examination and discussion of clay beds exposed in the stream banks.
2012: The location of this stop is unclear. This Placemark is 0.5 miles south from the exit on route 9A. There is no bridge over a railroad, no new railroad station construction site, etc. A new station was opened in 1996, but the image from 1994 shows no construction yet where that went in. That would have been Northeast of Cruger, this point is south of Cruger, and the text indicates clay beds both northeast and south of Cruger.

STOP 3. PEEKSKILL HOLLOW CREEK: OUTWASH AND KAME DEPOSITS.
Walk along the northbound lane in the yard, bear right at fork between trailer home and concrete building, follow lane to gravel pit. This pit has been excavated into one of the many outwash and kame deposits in Peekskill Hollow. Some kames show ice contact features. At this site a kame delta has been overtopped by flood gravels suggesting a change from deltaic to high energy fluvial deposition.
2012: Became a golf course in 2004.

STOP 4. KAME DELTA.
Proceed into gravel pit. This is a large kame delta complex constructed by meltwater flow through the Highlands during development of the Shenandoah Moraine.

B6: A GEOLOGICAL CLIMB OF SCHUNEMUNK MOUNTAIN
WILLIAM J. TUCCI
Science Department
Valley Central High School
Montgomery, New York 12550
ROBERT KALIN
E.S.S. Department
Suffolk County Community College
Selden, New York 11784
GENERAL INTRODUCTION
This trip focuses on the area known as the Hudson Lowlands. To the east are found the Hudson Highlands, an area of Precambrian terrane of high relief which strikes northeast-southwest. The Catskill Mountains of Devonian age, with Silurian and Lower Devonian outcrops along their eastern front are found to the west. The Hudson Lowlands are an area of relatively low elevation which are underlain by Cambro-Ordovician calcarenites and argillites. It is part of a physiographic trough that extends from the St. Lawrence Valley south into Pennsylvania. This region has a maJor down-fold referred to as the Schunemunk Outlier. Schunemunk Mountain which is a portion of the central axial region has a height of 507 meters (1664 feet). The synclinal fold that makes up the axial region of the lowlands has flanks upon which older rocks are exposed in topographic highs. The central part is underlain by the youngest rocks which, being resistant sandstones and conglomerates, form ridge-like masses of northeast-southwest trend along the axis. (Kothe, 1960).
The word Schunemunk, pronounced Skun-uh-munk, is the Algonquin Native American name given to the mountain by its early inhabitants. The name means "excellent fire-place" in the Algonquin language and may be the result of the fact that this group at one time occupied a fortified site somewhere near the northern end of the mountain.
Schunemunk is a folded and faulted mountain, unlike the Catskills to the north and west which are erosional remnants of a plateau. Schunemunk is a complexly folded and faulted remnant of the Devonian. Despite the ravages of glaciers, erosion, mass wasting, and the frost action of the Hudson Valley, it stands out as one of the highest peaks in Orange County and one of the highest west of the Hudson River.

B6: A GEOLOGICAL CLIMB OF SCHUNEMUNK MOUNTAIN

Notice the use of the Schunemunk Conglomerate as a building material.

STOP 1: DEVONIAN FOSSILS
USE CAUTION HERE. THIS IS AN ACTIVE RAIL LINE. Park vehicles west of the tracks and proceed along the tracks about 110 meters (363 feet) to a worked outcrop of the Lower Devonian Esopus Formation (Lowe, 1958). This outcrop contains a wide variety of brachiopod and pelecypod fossils and (rare) trilobite fossils, as well as ripple marks in the tilted bedding planes. Note that Schunemunk Mountain is visible at N 15 E from this point.

Note glacial erratics and stratified sand and gravel deposits of glacial origin on the left of N.Y. Rte. 32.

Cemetery of the Highlands. Note the use of Schunemunk Conglomerate to build cemetery walls.

STOP 2: KAME TERRACE
Proceed north along the unsurfaced quarry road to a large outcrop of Precambrian schist and gneiss exposed by a quarrying operation. Glacial striae, grooves and chatter marks are common on the glacially polished bedrock. A fine view of Schunemunk Mountain can be observed to the southeast from the top of the exposure. This site is an abandoned sand and gravel quarry. The glacial deposits appear to have been formed as melt waters flowed from the edge of the ice and deposited their sedimentary load at the base of the Precambrian outcrop (Sorrentino, 1979). Much of the original formation has been removed by the quarrying operation. A variety of cobbles, pebbles and sand has been deposited against the bedrock of the Hudson Highlands. Return to the vehicles and continue north on N.Y. Rte. 32.

STOP 3: GROUND WATER
Follow the faint foot path through the cornfield. Observe the hillside to the south (left) of the dirt road for traces of surface water. Proceed about 160 to 170 meters (approx. 500 ft.) along the trail to a large oak tree bordering the woodland on the north. At this point the land to the south slopes upward and a small spring, which flows throughout the year will be observed emerging from the plowed field. About 100 meters (300 feet) further along the trail note a concentration of erratic boulders along the north side of the path. The boulders are part of a ground moraine, a deposit left by glaciers melting in place. Take note of the size and shape of the boulders.

STOP 4: RAPIDS OF BABY BROOK
Baby Brook is a youthful stream and is actively downcutting its bed. Several Important observations and definitions can be made at this stop: earth flows, gravity falls, solifluction, "V" shaped valleys, mass wasting, and hillside creep. Observe the large boulders in the stream bed and the curved boles of the trees along the sides of the stream.

STOP 5: WATERFALL OF BABY BROOK
Cross the railroad track and continue along the trail following the yellow markers. Walking time expended about 40 to 45 minutes. You will hear Baby Brook far below in a steep valley it has cut into the softer sandstone (Bellvale) below the resistant Schunemunk Conglomerate capstone.
Note the nature of the bedrock that is visible on the trail surface. This is part of the Hamilton Group which consists of Devonian sandstones. At about 50 minutes walking time a small side trail to the west will appear. This trail leads to the Baby Brook Falls. Here one can observe the Schunemunk Conglomerate as bedrock for the first time. The conglomerate acts as a resistant cap-rock which produced Baby Brook Falls. Beyond this point note the preponderance of Schunemunk Conglomerate (with its dark reddish brown matrix and milky quartz pebbles). Continue along the Jessup Trail (yellow markers).

STOP 6: APPROACHING THR SUMMIT OF SCHUNEMUNK
This site is said to be the site of an Algonquin Indian encampment. The connection between geology, topography, ecology, and the Algonquin's adaptation to these natural features can be explored. The participants should be encouraged to find the connection between these factors by placing themselves in their position and exploring their needs for food, shelter, wood, game, water, and protection from their enemies. Return to the Jessup Trail (yellow markers) and continue toward the summit. Along the way the many glacial features of the mountain should be noted: glacial polish, faceted pebbles of the Schunemunk conglomerate, chatter marks, plucking, and "white" carbonate erratics which have been transported from the north.

STOP 7: THE SUMMIT
From this elevation much of the topography of the region can be observed: the Catskills, the Shawangunks, and the Hudson Highlands. A question poses itself at this point: Why have Schunemunk and Woodcock Mountain, part of a nappe, (a remnant of a sheet like, allochthonous rock unit that has moved in a horizontal surface) remained?

STOP 8: THE MEGALITHS
The Megaliths are the result of faulting. These large blocks, originally fractured by faulting, have tumbled together to form "caves" as a result of glacial plucking and/or mass wasting. Snow can sometimes be found well into spring in these "caves". At this location many I features of faulting and jointing can be found. Joints, joint pairs, faults, slickensides (show direction of movement), frost heaving, and weathering can be identified.

62nd Annual Meeting
Gary G. Lash, Editor
Department of Geosciences
Fredonia, NY 14063
State University of New York College at Fredonia
Fredonia, New York 14063
cover: Barcelona Light, Aimee Tourgee
PREFACE AND ACKNOWLEDGEMENTS
On behalf of the Department of Geosciences and the State University College at Fredonia, I welcome you to the 62nd Annual Meeting of the New York State Geological Association. We have attempted to provide you with a variety of trips that display the geological diversity of western New York. The trips run the gamut from oil and gas exploration to glacial and coastal processes to paleoecological and paleoenvironmental considerations of various stratigraphic units exposed in western New York and ontario.
I wish to thank the field trip leaders and particularly those who made life easier by submitting their manuscripts on time. Mr. Jack Ericson of the College Archives provided the cover figure of Barcelona Light. I am grateful to Nancy Jagoda, our department secretary, for her invaluable assistance in this undertaking. Fredonia state students Blaine smith, Kurt Schober, Kevin McGovern, and Richard Newman assisted in all phases of preparation of the guidebook. Eileen and Jocelyn Lash, Walther Barnard and Jason David Pacos helped to print and collate various chapters of the guidebook. Last but certainly not least, Janet Wentz, Tom Gestwicki and Dave Lillie of the campus Printshop provided valuable technical assistance as well as much needed space.

SatA: DEVONIAN STRATA AND PALEOENVIRONMENTS: CHAUTAUQUA COUNTY REGION: NEW YORK STATE
GORDON C. BAIRD and GARY G. LASH
State University of New York College at Fredonia
Fredonia, New York 14063
The history of the study of the Paleozoic stratigraphic divisions in New York State spans, at least, two centuries, and it records the early development of important concepts centrally germane to the study of sedimentary basins worldwide (see Tesmer, 1989). The works of James Hall, John Clarke, Henry S. Williams, Joseph Barrell, and George Chadwick are well known to most sedimentary workers, as are those of numerous subsequent workers. In particular, the sedimentary sequences of the Allegheny Plateau Region ("Southern Tier" region) served as important sources of information for refinement of the facies concept and for the widespread recognition of the westwardly prograding Catskill Delta Complex which is the primary Paleozoic story recorded in Southern Tier bedrock deposits (see Chadwick, 1924, 1933; Cooper, et al., 1942; Caster, 1934; Woodrow, 1985).
The first significant geologic work relating to the Chautauqua County region was presented in James Hall's (1843) Survey of the Fourth Geologic District. Subsequent stratigraphic studies in this area include Clarke (1903), Chadwick (1923, 1924), Caster (1934), Pepper and de Witt (1950, 1951) and de Witt and Colton (1953). In northwest Pennsylvania, significant synthetic contributions include I.C. White (1881), Butts (1906-1908), Chadwick (1925), Caster (1934), Pepper et al. (1954). In Ohio, deposits equivalent to parts of the New York and Pennsylvania Upper Devonian section (Chagrin Shale) have been the subject of recent paleoenvironmental studies (see Weidner and Feldmann, 1983; Schwimmer and Feldmann, 1990). The present authors particularly build from the comprehensive work of Tesmer (1963) and the subsequent work of Murphy (1973) and Burrier (1977).
Both prior- and ongoing studies of the present authors are directed to the Canadaway-Chadakoin succession exposed on the Lake Erie lowland plain and adjacent escarpment. One of us (Baird) is currently tracing Chadakoin strata from Ohio northeastward along the escarpment to the vicinity of Fredonia, and he is also examining eastward (upslope) facies changes associated with the base of the Dunkirk Shale Member. Lash is currently working on the origins of interbedded siltstone-shale deposits and massive siltstone units (Laona and Shumla members) within the Canadaway Formation.

SatA: DEVONIAN STRATA AND PALEOENVIRONMENTS: CHAUTAUQUA COUNTY REGION: NEW YORK STATE

Cross Canadaway Creek. Gowanda Shale exposed in vicinity of bridge.

Several levels of river terraces
Several levels of river terraces are exposed on each side of bus at this point associated with earlier and higher stages of Lake Erie.

Cross Canadaway Creek bridge.
Good exposures of the upper part of the Gowanda Shale by bridge are continuous up to falls at Laona.

Stream terraces can be seen on the right side of the bus.
An abandoned oxbow lake can be observed 8 meters (25ft.) above the present level of the creek.

STOP 1. Laona Siltstone Member
Laona Siltstone over Gowanda Shale at waterfall 200 feet southwest of car park at bridge (Overlook Stop Only; we will be able to sample from this division at STOP 4). Note the sharp contrast between the conspicuously banded ("zebra" facies) of the Gowanda and the massive nature of the overlying Laona. The Laona and the higher Shumla siltstone are believed to be gravity-flow units which record downslope movement of silt or fine sand into the anoxic to minimally dysoxic lower slope-basin setting recorded by the Gowanda-Westfield-Northeast shale members.

Pass Al-Tech Corp. factory (to right).
OHM 2015: Became AlTech Specialty Steel State Superfund Site Number 907022 after Al-Tech went bankrupt in 1999.

STOP 2: Hanover Shale-Dunkirk Shale Contact At Point Gratiot
Point Gratiot is the type section for the Dunkirk Shale Member. Along the northeast side of the point the lower part of the Dunkirk is visible as is the uppermost 1 to 2 meters of the underlying Hanover Shale Member (Fig. 4A). The bioturbated grey Hanover contrasts strongly with the laminated brownish black beds of the Dunkirk. Pyritic burrow tubes are conspicuous in the uppermost Hanover and in the thin, 13.5 cm (4.5 in.), recurrent Dunkirk grey mudstone interval above the basal 15-17 cm (6.0-6.5 in.)-thick basal Dunkirk black bed, but no body fossils occur in the grey lithology except for pyritic goniatite steinkerns and wood debris; this grey sequence is classic for slowly deposited dysoxic facies (Rhoads and Morse, 1971; Byers, 1977).
The Dunkirk Shale is non-bioturbated at most levels but there is some evidence of internal burrowing as can be seen in the basal black bench. Body fossils in the Dunkirk are usually uncommon; the linguloid brachiopod Barroisella camhbelli occurs at some levels and both wood debris and fish fragments ave been found. The top of the basal black bench is particularly good for carbonized logs and fish debris (Fig. 4A); when viewing is optimal, a thirty foot-long tree trunk is visible on the surface. In the spring of 1986 one of us (Baird) and several S.U.C. Fredonia geology students recovered a partial skeleton of the giant arthrodire Dunkleosteus from this bed.
Although a bioturbated, conformable contact between Hanover and Dunkirk can be seen below the basal Dunkirk black bed which dips southward below the water at this section, the top of the 13.5 cm Dunkirk grey mudstone bed marks a submarine erosion surface which is "roofed" by black Dunkirk deposits; this contact is marked by abundant detrital pyrite in the form of reworked burrow tube fragments, nodules, and occasional goniatite steinkerns derived from the underlying grey mudstone interval which is conspicuously rich in pyritic tubes and nodules (Baird and Brett, 1986). Additional reworked components include fish bones, conodonts, and carbonized wood fragments. The abundance of wood and conodonts in the basal few centimeters of the overlying black shale suggests that this interval is unusually condensed, recording the descent of numerous logs from the water surface over a long period of time. This wood-rich unit also records bioturbation, which, at this section, was sufficient to flux the broken pyritic tubes into random orientations. Bottom erosion is believed to be due to sediment starvation on the seafloor during relative sea-level rise. Scouring of the substrate may have been accomplished by rare deep storm waves, bottom currents in the basin, or internal waves impinging a regionally sloped substrate (Baird and Brett, 1986; Baird et. al., 1988). Exhumed and concentrated detrital pyrite was preserved (not oxidized) in the anoxic to minimally dysoxic Dunkirk bottom setting.
In the early 1980s George McGhee and Edward Olsen sampled this section for the occurrence of iridium, a trace element believed by some to mark catastrophic extraterrestrial collision events in the rock record (see Alvarez et al., (1980). The Late Devonian Frasnian-Famennian (F-F) extinction event, one of five greatest Phanerozoic extinctions, was, until recently, believed to be coincident with the base of the Dunkirk. This event is similarly thought by some to be the possible record of an impact (Goodfellow, et al., 1988). However, no Iridium-rich horizon was found (McGhee,1982, 1988). Recent bistratigraphic work indicates that the F-F boundary is somewhere within the upper Hanover (Klapper, Kirchgasser pers. comm.) at a level which has not been precisely identified.
Note the "bedded" till above the Dunkirk and the striated bedrock contact below this "till."

Cross Canadaway Creek.

County Fly Ash Dump to the left (see Field Trip G, this volume).

Bridge over Little Canadaway Creek.

Entrance to Lake Erie State Park

Bridge over Slippery Rock Creek.
Exposures include the South Wales Member at the lake shore level and Gowanda Member at the bridge and upstream.

Bridge over Corell Creek.
Exposures are in the Gowanda Shale Member. The Corell's Point pyrite-goniatite bed is exposed approximately 120 feet upstream from the bridge.

STOP 3: Corell's Point Pyrite-Goniatite Bed In Gowanda Member
The Corell's Point Pyrite-Goniatite Bed, encompassing two regionally mappable levels of calcareous septarian concretions, is present at several creek localities in this county but this shore exposure is the best place to examine fossils and sedimentary structures (Fig. 4 B,C). At least two, laterally discontinuous beds rich in pyrite nodules and locally abundant pyritized cephalopod steinkerns can be traced within the lower septarian concretion zone along the shore and around the small headland. Goniatites include Cheiloceras amblflobum, Tornoceras concentricum, and Aulatornoceras bicostatum (Fig. 4C ; these belong to the zone of Cheiloceras (II) in the Famennian (see House, 1966; Kirchgasser, 1974). Orthoconic cephalopods are also common; these are commonly encrusted by a reptate auloporid coral. Slightly-curved conical shells less than one inch in length may be bactritid cephalopods or coleolid tubes. Bivalves, including Lunulicardium eriense, Praecardium multicostatum and Loxopteria corrugata occur with the cephalopods but these are usually preserved as non-pyritic composite molds often with a faint organic patina which may be a remnant of the periostracum layer. Driftwood, usually partly carbonized and partly permineralized by pyrite, occurs with the other fossils. Spectacular large Zoophycos spreiten in the Corell's Point Bed indicate that this trace had become important in offshore, dysoxic facies by the Famennian.
Babcock (1982), believed that the fauna of this bed was selectively preserved by turbiditic smothering events; some beds in this unit have shallow sole marks and display lamination similar to those in flaggy siltstone beds elsewhere in the Canadaway Formation. However, evidence of periods of reduced sediment influx is shown by intense bioturbation at some levels and by the tendency for auloporid corals to not only colonize partly-buried cephalopods but to extend colonial growth onto the adjacent seafloor. The history of this unit is complex and the presence of so many fossils at this level is suggestive of an episode of increased bottom oxygenation and reduced average turbidity.
The Corell's Point Bed is well exposed in Corell's Creek, Slippery Rock Creek near Brocton, Little Canadaway Creek near Lamberton, Canadaway Creek upstream from Route 20, and Walnut Creek at Forestville (House, 1966, 1968).
Examine the Gowanda-strata both below and above the Corell's Point Bed; notice the numerous brown-black shale beds which alternate with grey-green mudstone to produce the conspicuous striped banding along the shore (Fig. 4 B). This basinal "zebra" facies will be discussed in greater detail at STOP 4.

To the left (south) observe the elongate glacial landforms
To the left (south) observe the elongate glacial landforms which characterize this specific part of the lake plain. These deposits may represent reworked sand from older sand deposits of higher lake stages.

Bridge over unnamed creek south of golf club.
Exposures of Gowanda Shale include a 4.5 m (15ft.) waterfall at the lake and a conspicuous fossil wood concentration in a siltstone bed between the falls and Route 5.

STOP 4: Gowanda, Laona, And Westfield Members
Bridge over Bournes Creek. Park on shoulder and enter property on left (south) of Route 5.
This outcrop on Bournes Creek affords an opportunity to examine the Laona Siltstone over the Gowanda Shale and to sample the lower part of the still-higher Westfield Shale upstream from the waterfall. The Laona is expressed here as three massive, but relatively thin, siltstone beds which are separated by intervals of interbedded black and green shale ("zebra" facies). It is much more poorly developed here than at STOP 1 or in creeks between here and Barcelona (see road log below); apparently the Laona gravity-flow event involved channelization of the mobile silt such that this unit develops the thick, massive character only locally. Here it appears to be represented by three discrete flow events which must have occurred at separate times.
We will hike upstream to examine the lower Westfield section which is characterized by good development of the finely interbedded black and green-grey shale deposits ("zebra" facies) that are characteristic of much of the Canadaway succession (Figs. 6, 7). The black shale bands, typically less than one inch-thick, are usually laminated and they can be quite silty; some appear to grade laterally into siltstone beds, commonly containing wood debris. Grey mudstone beds sometimes pinch out laterally allowing black beds to merge. The grey mudstone deposits are fine grained and minimally bioturbated such that they appear structureless on a fresh break surface. The grey beds appear to be composed of turbiditic mud; there appears to be a spectral gradient from the grey mudstone layers through silty mudstone beds with incipient sole mark development to cross-laminated siltstone beds with good sole marks; at an initial glance, this would appear to be reasonable suite of bed-types that one might expect to see in an ancient prodelta slope environment where turbiditic silt was scarce with respect to mud.
However, complex internal cross-lamination of many siltstone beds suggests that processes other than turbidity currents may have produced them and that some beds may record multiple depositional events (see Stanley, 1987). Moreover, it appears that, at least, some of the thin black shale beds do not simply record stagnant anoxia and slow accumulation of organic-rich mud. Beneath many, if not most, thin black shales beds is a millimeter-thick zone of pyritic microspheres and partial microspheres which appear to have formed in situ within the uppermost, water-rich grey mud layer (Figs. 6, 7). Most of these are partial spheres with brilliant curved exteriors and flat tops marked by dull polyframboidal granular surfaces (Fig. 7). Some bear crenulated shiny exteriors reflecting compressive burial affects following formation of the pyrite.
These sand-size microspheres apparently record early diagenetic, bacterially-mediated pyrite formation within spherical spaces. We suspect that surface-ward migration of CO2 or methane may have produced bubbles which became trapped under the black mud layers or under bacterial mats associated with the black muds (Fig. 7). Sulfidic activity resulted in the partial-to-complete filling of the bubbles leaving the partially filled ones as useful geopetal indicators. Within the basal few millimeters of many black shale beds, the microspheres are again visible. However, partial microspheres are randomly reoriented, indicating that they have been disturbed after formation. Evidently microbioturbation during black mud deposition served to reorient the pyrite in some instances. In other black shales, the microspheres are concentrated in lag concentrations; this suggests that these black shale layers may have been deposited under the influence of tractional currents. Cuomo and Bartholemew (1987) and Cuomo and Rhoads (1987), have observed that both modern and ancient black muds are extensively pelletized by bottom organisms. If this is true, then the pelletized black mud may have been easy to mobilize through current action because it would have been like "Sand" or "silt". It is then possible that some of the thin black bands in the Canadaway Formation may be analogous to some of the tractional siltstone beds to which they sometimes laterally intergrade. Study of these complex and somewhat enigmatic deposits remains an on-going project.
In-situ microspheres are abundant beneath some of the black bands at this stop. Reoriented and hydraulically concentrated microspheres are locally common along the soles of siltstone beds where they have collected into scoured depressions, (corresponding to "positive" flutes, grooves, and excavated burrows) along such surfaces.

Unnamed creek to right (north).
Thick Laona section is present downstream from road.

Pass Barcelona Harbor complex.
Excellent shore exposures into the Gowanda Shale are developed north of dock area. This is a particularly clean section for observing "zebra" facies. Stone lighthouse was first to be illuminated by natural gas in the U.S.A.

Crossing Glacial Lake Whittlesey beach berm.

Cross Little Chautauqua Creek Gorge.

STOP 5: Northeast Shale Along Chautauqua Creek
At this brief stop we will examine a cutbank section and associated loose siltstone slabs which are typical of the Northeast Member. The Northeast is a typically "flaggy" sequence of thin grey siltstone beds interbedded with silty grey mudstone. Some siltstone layers appear to be turbidites which lack the basal graded division of the typical Bouma-sequence. Many beds display good sole marks with groove- and tool-marks. Networks of the trace fossil Planolites are common, and a trace resembling Zoophycos occurs more rarely. Some sole marks show hydraulic concentrations of exhumed and transported pyritic microspheres ; and partial microspheres in groove- and flute-casts; these were current-scoured depressions into which the coarser and heavier pyrite material selectively accumulated as currents waned. Cone-in-cone concretions occur at several levels within the Northeast Shale (Woodland, 1964; Gilman and Metzger, 1967); fragments of such concretions are occasionally observed in creek rubble at this stop. In-situ shelled fossils are rare to absent here as at many other sections of the lower Northeast Member. This facies records a dysoxic prodelta setting below the reach of most storm waves.

Start to cross lip of prominent lake escarpment
Start to cross lip of prominent lake escarpment marking edge of Allegheny uplands.

Group of buildings is hamlet of Summerdale.

STOP 6: Foerstia (Protosalvinia) Zone Within Ellicott Shale Member
Exposures of the Chadakoin Formation on Chautauqua Creek are the most complete in New York; the lower division (Dexterville Siltstone Member) is entirely exposed, and approximately 75 to 80 percent of the overlying Ellicott Shale Member can be observed on this creek and along its upper tributaries (Fig. 8). Recent discovery of about 38 meters (120ft.) of additional measureable Ellicott in a side tributary bordering Lyons Road allows us to observe a major siltstone division yielding the distinctive large rhynchonellid brachiopod Paurorhyncha newberryi (Figs. 8, 9): which has not been recorded prior to now within the county (Tesmer, 1963). In addition, discovery of the important algal taxon Foerstia (Protosalvinia) in the section at this stop (see text) allows us to establish equivalency of this outcrop with key parts of the Ohio, Antrim, New Albany, and Chattanooga black shales between New York and Oklahoma.
According to correlations and measurements of Tesmer (1963), and Burrier (1977), the Lyons Road section is within the Ellicott Shale approximately 33 meters (105 ft.) above the Dexterville Member. Mapping by Baird shows that the Dexterville-Ellicott boundary of Murphy (1973), corresponds to a level in Chautauqua County which is approximately 33 to 38 meters (105-125 ft.) above that of Burrier (see text). The Lyons Road section correlates to Murphy's Dexterville-Ellicott lithologic transition and the zone of abundant Foerstia that are characteristically associated with it; the boundary between Murphy's two members is approximately at the 1400 foot-elevation (Fig. 8, 9) which is below the old road shoulder (parking area for group) adjacent to the defunct bridge. This level also corresponds to an upward transition from siltstone-dominated "distal platform" Ellicott facies of Burrier (1977), to his mudstone-rich "prodelta" deposits at the upper end of his measured section. We will cross the mowed field area and collect from shell-rich, silty deposits near the boundary between the siltstone-dominated and upstream shale-dominated intervals.
Downstream from the bridge vicinity is siltstone-dominated, fossiliferous delta platform ("Chemung") facies of the Late Devonian (Rickard, 1975). The most conspicuous features are lenticular siltstone and fine sandstone beds interspersed with grey mudstone layers and coquinitic shell accumulations. Unlike the thinner and more continuously even-bedded slope and basin siltstone beds in the Canadaway Formation, these layers pinch and swell and there is abundant evidence of erosional truncation of older beds by younger ones. Storm layers dominate the section; tempestites, pararipples, occasional thick siltstone beds with hummocky cross-stratification, and gutter casts are all evidence for the impingement of storm waves on the substrate. Good tempestites display a weakly graded concentration of reworked shells, overlain by laminated siltstone with low inclination cross-stratification displaying internal bedding discordances (see Aigner, 1985). Gutter casts are erosional runnels, usually less than a meter in length which often have interiors similar to tempestites; siltstone- and shell-filled gutters are the result of scour- and filling-processes involving both oscillatory and unidirectional currents during storms (Aigner, 1985). These runnels are presently casted with siltstone and coquinites and they display "tool marks" produced by the bouncing and rolling of shells, wood, and other debris during the storms. Sole marks under many siltstone beds show disarticulated brachiopod shells visible as concavities on the sole surface; this is the result of mud "sheltering" beneath the stationary shell during the storm which is subsequently buried by silt. Later differential weathering removes the sheltered mudstone leaving the shell as a negative feature on the siltstone surface. Chadakoin storm beds decrease in size and complexity downslope into Pennsylvania and Ohio along a depth-controlled proximity gradient (see Aigner, 1985); this gradient can be better assessed through refined stratigraphic mapping within this formation.
Not only are the thick proximal storm beds represented in this section but thin, mud-dominated layers produced by smaller storms are common, particularly upstream in the shaley Ellicott interval. These distal tempestites record the transport and settle-out of mud which often smothered bottom organism as currents dissipated (Brett, et al., 1986). Excellent examples of articulated delicate fossils, including crinoids, echinoids, and glass sponges, found at the Lyons Road section attest to numerous bottom-smothering events recorded in this outcrop.
Abundant fossils belonging to a few standard brachiopod and bivalve genera can be collected here. Brachiopods including the rhynchonellid Camarotoechia contracta, the spiriferid Cyrtospirifer nucalis, and a productid Productella speciosa are ubiquitous, as are the bivalves Mytilarca chemungencis and Leptodesma patens. In particular, notice the partially dissolved character of the brachiopod shells. Evidently, carbonate undersaturation in the near surface muds and/or oxidation of pyrite in these same muds caused many of these shells to undergo variable amounts of dissolution. Fossils to look for include hexactinellid sponges, articulated inadunate crinoids and undescribed archaeocidaroid echinoids. Small fossils include the fucoid algal structure Foerstia and abundant black, chitinous polychaete jaw elements called scolecodonts. The best Foerstia can be collected from shelly beds in the vicinity of- and downstream from the junction point of the north-trending, gently sloped path with Chautauqua Creek (Fig. 9). These resemble 0.5 to 1.0 mm diameter black "tar splatter" marks on bed surfaces which frequently are branched in a characteristic "Y" pattern. A few bedding surfaces are crowded with this important fossil.

Cattaraugus exposure on left side of road.

Ellicott Shale on right and left side of road for next half mile.
It is rich in sideritic lentils and characterized by some pyrite-rich mudstone beds, fossils are scarce.

Cross Prendergast Creek.
Ellicott Shale along creek below bridge. Foerstia bearing strata equivalent to the section at STOP 6 occur along this creek north of (downstream from) Route 17 above the Stedman-Sherman road crossing at an elevation of 1380-1390 feet.

STOP 7: Strata Of Uppermost Ellicott Member
Ellicott Shale on left and right side of road for next 0.25 mile. Stop vehicles at west (downhill) end of section.
This will be a brief stop to examine beds in the highest Chadikoin Formation. In the lower part of the cut and, particularly in the drainage ditch, one can observe brachiopod coquinites associated with storm (tempestite) beds. The characteristic upper Ellicott rhynchonellid brachiopod Paurorhyncha newberryi occurs at one or two levels in this roadcut. Of particular interest are shells stacked like dishes due to the oscillatory motion of storm-currents on the substrate (see Kidwell and Aigner, 1985; Kidwell, 1986). The elevation of the upper (eastern) end of this outcrop is approximately 10 to 15 meters (30-50 ft.) below the projected level of the Panama Conglomerate which can be seen on the hill immediately south of this area (Tesmer, 1963).

We are crossing the northern limit of the "Bass Islands" structural trend
We are crossing the northern limit of the "Bass Islands" structural trend of drillers. The base of the Panama Conglomerate is anomalously elevated to approximately 1740 feet in this immediate area. Note abundant evidence of drilling activity (blue pumps and tanks) in nearby fields.

STOP 8: Panama Conglomerate Member Of Cattaraugus Formation
The Panama Conglomerate, named by Carll (1880), for 21 meters (70ft.) of quartz-pebble conglomerate and quartz-dominated sandstone exposed at Panama, Chautauqua County, is a conspicuous lenticular unit at the base of the Cattaraugus Formation (see Tesmer, 1963, 1974). It is one of several conglomerate-rich units within the Cattaraugus Formation of Chautauqua and Cattaraugus counties. The Panama is correlative with the LeBoeuf Sandstone in Erie County, Pennsylvania and in western Chautauqua County.
The Panama Conglomerate Member is composed of cross-bedded, quartz pebble conglomerate, quartz-rich sandstone and sandstones with dilute (sand-supported) pebble concentrations. Conglomerates are composed mainly of quartz pebbles with minor components of jasper and metamorphic rock. Pebbles are usually less than one inch in diameter, well rounded, and often display a distinctly flattened discoidal to prolate shape. Rare fossils described from the Panama include Cyrtospirifer chemungensis, Camarotoechia contracta, Ptychopteria sao, as well as gastropods, (Tesmer, 1963; Miller 1974).
Miller {1974) interpreted the Panama to be a "beach" or "near beach" deposit with the main sediment source area to the southeast. One line of evidence he used was the tabular shape of many quartz pebbles in the Panama as opposed to the more ovoidal pebble shapes he observed in the "fluviatile" post-Devonian Knapp and Olean conglomerates (see also work of Sames, 1966); abrasive imbricate stacking and sliding of pebbles in a beach-foreshore environment was cited to explain the tabular pebble condition. In addition, the distinctly bipolar (NW-SE) paleocurrent pattern for measured cross-bedding sets within Panama (Miller, 1974) appears to reflect tidal current processes acting in a coastal setting. The occurrence of brachiopods and marine mollusks in the Panama is further evidence of marine influence in this deposit.
A major question that geologists confront when examining deposits such as these is the problem of transporting and accumulating the vast numbers of quartz pebbles in this outcrop; clearly, a great volume of source terrain must have been denuded to produce it because vein quartz, chert nodules, and pegmatitic quartz make up only small volumes of normal lithosphere. This problem is partly obviated by the fact that the Panama Rocks outcrop is really more a thick lentil or channel feature which attenuates laterally to thin Panama facies dominated by sandstone (Tesmer, 1963; Miller, 1974). Hence, the volume of Panama quartz pebbles is really much less than this outcrop would initially suggest. Many of these pebbles may have been recycled from conglomerates in older Paleozoic units. Conglomerates are conspicuous features in the Ordovician Bald Eagle and Juniata divisions, the Silurian Oneida-Shawangunk and Tuscarora deposits, and in Middle through Upper Devonian proximal deltaic deposits of the Catskill Delta; Acadian overthrusting events probably exposed some or all of these easternmost sedimentary divisions to erosion, thus freeing up older pebbles for recycling. Post-Chadakoin sea level-fall and westward-northwestward advance of the paleoshoreline in western New York and northwest Pennsylvania probably served to introduce large numbers of quartz pebbles into the Chautauqua County region.
Many questions remain unanswered concerning these conglomerate units and the non-conglomeratic facies in between them. There are very few places where basal Cattaraugus (Venango) coarse facies can actually be seen in place rather than as slump blocks in creek beds or on wooded hillsides; it is essential to observe upper and lower contacts of units such as this to establish any sense of context for these units as geological events.
For those particularly interested in landscape and groundwater processes Panama Rocks offers a superb view of slope creep in action as well as weathering processes along joint systems developed in this deposit. The numerous "Dens" and "Alleys" between blocks also provide opportunity to examine the important role of "root pry" in forcing blocks apart. This park is one of several such tourist areas developed in conglomerate-rich deposits in this region.

Cross Prendergast Creek and continue over Kent ground moraine
Cross Prendergast Creek and continue over Kent ground moraine to vicinity of Chautauqua Lake.

Pleistocene and Recent alluvial sand and silt.
For the next several miles we will traverse over Pleistocene and Recent alluvial sand and silt.

Ascend Lake Warren beach berm.
Rt. 20 follows the top of this beach ridge for the next 8 miles. Numerous vineyards and orchards are developed on the sandy soil, as are numerous sand and gravel pits.

Cross Little Canadaway Creek.
Resistant siltstone beds within Gowanda Shale hold up waterfall 100 feet downstream from road.

Cross Canadaway Creek.
Monument (inscribed boulder) to left marks position of the first successful gas well which was drilled in 1825).

SatB: GEOLOGY AND OIL AND GAS EXPLORATION IN WESTERN NEW YORK
Jerold C. Bastedo (Ecology and Environment, Inc.)
Arthur M. Van.Tyne (Van Tine_ Consulting)
HISTORY OF OIL AND GAS DRILLING IN WESTERN NEW YORK ·.
SEEPS
Long before any drilling took place, local Indians had found natural oil and gas seeps at several places in western New York. The first recorded observation by white men of such an occurrence was in 1627. In a letter written in that year a Franciscan priest described his visit to the Cuba oil spring in Allegany County. He was taken there by a band of Indians who had used the oil at various times for medicinal, fuel and ceremonial purposes.
In 1669 Indians took the French explorer LaSalle and his party to a natural gas seep which they knew of in western Ontario County. While there, they lighted the gas and watched it burn. The event was recorded in a diary by one of the party and this account was later published.
FIRST WELLS
Possibly the first gas well drilled anywhere was located in the bed of Canadaway Creek where it flows through Fredonia. In 1821, William A. Hart, drilled a hole into the shale there to a depth of 70 feet and obtained a flow of gas. He piped and sold the gas to various places of business in the Village and it was also used to light street lamps.
According to Herrick (1949) the Hart well was still producing gas in 1858. From 1821 to 1858 others produced gas for commercial use, with varying success, from gas seeps in the Fredonia area. In 1858, searching for an additional supply of gas, Preston Barmore and Elias Forbes made a location for a new gas well. This was near a gas seep in Canadaway Creek about one mile north of the Hart well. The new well consisted of a dug cavity about 30 feet deep in the bottom of which two holes were drilled to depths of 100 and 150 feet. The holes found gas and the well was hooked up to supply gas to the Village.
In August of 1859 Edwin L. Drake made his great oil discovery near Titusville, Pennsylvania. That 69.5 foot hole showed that oil was reservoired in rocks and could be recovered from rock in greater quantity than from a seep by drilling a well into it. After the Drake discovery men began to drill all over western Pennsylvania and southwestern New York looking for oil.
No road log available at time of publication.

SatC: SEQUENCE STRATIGRAPHY OF THE TYPE NIAGARAN SERIES (SILURIAN) OF WESTERN NEW YORK AND ONTARIO
Carlton E. Brett, William M. Goodman And Steven T. LoDuca
Recent advances in sequence stratigraphy resulting from seismic profiling of continental shelf sedimentary prisms (Vail et al., 1977; Wilgus et al., 1988), combined with a renewed interest in cyclicity and periodicity in the sedimentary record (see, for example, Bayer and Seilacher, 1985; Einsele, 1985; Fischer et al., 1985; House, 1985) have had a revolutionary impact on the field of stratigraphy. Subdivision of sedimentary prisms into unconformity-bound, genetic stratal packages, or sequences, (sensu Vail et al., 1977; Fig. 1) has permitted seismic stratigraphers to make rather detailed intercontinental correlations and has provided a new genetic model of stratigraphic dynamics on continental shelves (see, for example, Van Wagoner et al., 1988; Posamentier et al., 1988a, b; Sarg, 1988; Galloway, 1989). If depositional sequences are produced, at least in part, by eustatic sea level fluctuations, then the principles of sequence stratigraphy should be equally applicable to epicontinental sea and foreland basin strata which appear to be highly influenced by high frequency, low magnitude sea-level oscillations (see, for example, Goodwin and Anderson, 1985; Busch and Rollins, 1984). However, to date, relatively few studies have attempted to discern unconformity-bound sequences in settings other than passive continental margins (notable exceptions include Nummedal and Swift, 1988; Cross, 1988). In order to test the applicability of sequence concepts to epicontinental strata, field geologists must begin to apply the model at an outcrop scale to a broad array of sedimentary environments. Only in this way can the generality of the sequence model be tested and peculiarities of continental interior and foreland basin sequences be distinguished from those characteristics specific to continental shelf deposition.

SatC: SEQUENCE STRATIGRAPHY OF THE TYPE NIAGARAN SERIES (SILURIAN) OF WESTERN NEW YORK AND ONTARIO

Note road cuts in cherty Onondaga Limestone (Middle Devonian).
This is the old Vogelsanger Quarry.

Cuts on left at underpass are in Upper Silurian Camillus Shale (and gypsum).

Bridge over Tonawanda Creek, enter Niagara County.

Type section of lower Gasport Fm. grainstone is cut on this road.

Small cut in red Grimsby Sandstone.

Note sewage treatment plant on left.

STOP 1A. Road Cut On W. Jackson Street Below Somerset Railroad Viaduct
(Queenston Shale- Medina Group).
This excellent and relatively new outcrop has been described previously in considerable detail (see Friedman, 1982; Duke et al., 1987). It provides an outstanding exposure of the basal Silurian Cherokee Unconformity and a good opportunity to study the lower units of the Medina Group as well as the uppermost beds of the Queenston Shale.
About 6 m (20') of upper red mudstones and siltstones of the Queenston Formation (Upper Ordovician, Ashgillian) are exposed at this locality. The Queenston has been interpreted as either very shallow marginal marine or non-marine red beds. The Cherokee unconformity in this area is the basal surface of Whirlpool Sandstone which is nearly planar. It is also a megasequence boundary separating the early or Creek phase of Sloss' Tippecanoe "megasequence" from the later Tutelo phase (see Dennison, 1989).
The Medina Group (Sequence I of the Silurian System), consists of an Early Silurian (early Llandovery, Al-B), siliciclastic wedge derived from tectonic source areas to the southeast (Figs. 1, 2). The lowest Silurian unit, white Whirlpool sandstone is about 3.5 m (11.5') thick at this location. Basal beds of the Whirlpool Sandstone are quartz arenites with northwest dipping cross strata which have been interpreted recently as nonmarine, braided stream deposits (Middleton et al., 1987). Large-scale channel-like structures occur in, or at least at the top of, these sands. Shale drapes within such channels at Lockport have yielded marine acritarchs (M. Miller, unpublished data) indicating that the channels were backfilled by very shallow marine sands and minor muds during a rise of sea level. Hence the irregular channeled surface that separates lower Whirlpool braided fluvial facies from upper Whirlpool hummocky cross-stratified, sparsely fossiliferous beds is a transgressive surface. The Whirlpool Sandstone thus is interpreted to contain both a lowstand (or shelf margin) systems tract and a transgressive deposit. A thin bed containing phosphatic pebbles and fossil grains occurs the Whirlpool-Power Glen contact. This phosphatic pebble bed may mark a marine flooding surface, or surface of maximum starvation associated with relatively increased rates of sea level rise. This surface marks the change from shallow shelf sands of the upper Whirlpool into deeper shelf muds and storm sands of the Power Glen Formation, herein interpreted as relative highstand deposits (subsequence IA). The Power Glen exhibits two small scale parasequences.
This outcrop is one of the easternmost exposures of the Power Glen Shale. At this locality the Power Glen Shale comprises of about 5 m (16') of greenish gray shale with thin tempestitic siltstone and sandstone beds. The basal meter-thick transitional zone consists of thin (2-10 cm) muddy sandstones with interbedded sandy shales. Sandstones in the Power Glen Shale feature small-scale hummocky lamination and gutter casts suggestive of shallow, storm influenced shelf deposition. Small burrows (Planolites) are common, but body fossils are rare.
Greenish to reddish sandy shales and reddish sandstones occur near the top of the Power Glen suggesting a minor upward shallowing trend. However, the top of the unit (as defined herein) is sharply demarcated at the base of a massive white to pink mottled sublitharenitic sandstone about 2.5 meters (7.7') thick. This unnamed unit corresponds with lenticular sandstone beds ("Devil's Hole Sandstone" of Duke et al., 1987) seen at Niagara Gorge (Stop 6). The basal and upper beds of the sandstone contain lingulid brachiopods and probable Lingula burrows.
The white sandstone appears to record a relative sea-level drop during which sands were distributed widely into the basin. The unit has some characteristics in common with the upper member of the Whirlpool Sandstone and, by analogy, is considered to be a relative lowstand to transgressive deposit.
The unnamed sandstone, in turn, is overlain by about 2.0 meters of brick red shales and interbedded sandstones assignable to the lower Grimsby Formation. These beds are ferruginous and exceedingly rich in fragments of lingulids with rare nautiloids and bryozoans. Thin spastolithic (oolitic) hematite stringers occur near the top of the unnamed sandstone and probably reflect reworking of sediments in shallow marine environments during an interval of sediment starvation. Hence, these shell-rich ferruginous sediments represent a condensed interval at the base of the Grimsby highstand deposits.
The reddish marine shales near the base of the Grimsby Formation pass upward into red and white-mottled sandstones and thin sandy shales. These beds are exposed high in the cut and are not readily accessible. This upper interval will be seen to better advantage at Niagara Gorge (Stops 4, 5, 6). Return to vehicles and reverse direction turning left at West Jackson Street.

OPTIONAL STOP 1B: Cuts Along Somerset Railroad
Northeast Of Niagara Street Crossing, Lockport, NY (Upper Medina And Clinton Groups)
Cut banks along both sides of the railroad track provide an excellent exposures of the upper beds of the Medina and Lower Clinton groups (Fig. 9). Lowest exposed units are reddish and white, mottled sandstones and sandy shales of the upper Grimsby Formation. A prominent 2.2 meter thick, pale pinkish sandstone unit (Thorold-equivalent), the overlying 3.0 meters (9') of red to greenish silty shale (Cambria Member), and about 0.5 m of pale greenish to white sandstone and sandy shale, referred to as the Kodak Formation, complete the Medina Group. The Lower Clinton Group (Sequence II) rests unconformably on the Medina Group with the contact marked by a thin phosphatic, calcareous sandstone. Only 24 cm (17") of Neahga Shale (Fig. 9) overlie the unconformity, followed by 1.9 m of crinoidal grainstone belonging to the Hickory Corners Member of the Reynales Formation. These units and the underlying Medina strata are comparable to the section seen at Lockport Junction Road (Stop 2A), and are described in greater detail for that section. The upper contact of the Reynales Limestone (upper sequence II boundary) is well exposed along the top of the cut on the southeast side of the railroad tracks. Here, the uppermost bed of Reynales crinoidal packstone crops out from beneath the soil cover. The surface is an irregularly sculpted and bored hardground with black phosphatic staining and what appear to be phosphatized stromatolites. This is a local manifestation of the major Upper Clinton unconformity.
Southwest of the main railroad cut are small, partially overgrown exposures along the southeast side of the tracks. Here a thin remnant of the upper Clinton Group (sequence IV and parts of V) can be observed. In the ditch, southwest of the end of the main outcrop are exposed about 37 cm of dark gray shale rich in phosphatic nodules. The unit, which yielded an acritarch assemblage identical to that of the Williamson Shale of the Rochester area, lies between the top of Reynales unconformity and the basal phosphatic bed of the Rockway Dolostone. The pale buff-weathering Rockway Member (0.5 meters thick) and its contact with the overlying pinkish gray grainstones of the Irondequoit Formation are visible in the small outcrop. Rochester Shale is poorly exposed in slumped banks between this outcrop and the Niagara Street crossing. Well-preserved bryozoans, brachiopods, and even cystoid calyces are occasionally found in patches of weathered shale along the southwest side of the tracks.
Return to vehicles and reverse directions, returning to the junction of Niagara Street and West Jackson Street.

STOP 2A: Lockport Junction Road Cut (lower)
(Upper Medina And Lower Clinton Groups)
This newly widened (1986) cut along Lockport Junction Road exposes a similar section to that seen along the Somerset Railroad cut (optional stop 1B). However, this cut does not show the upper Clinton beds.
The lowest beds are exposed beneath and just north of the overpass of Lower Mountain Road over Route 93. The basal units seen here are red shales near the top of the Grimsby Formation. These shales are overlain by a 1.0 to 1.2 meter thick, blocky, pinkish gray sandstone that displays color mottling due to bioturbation. Swirly spreiten of the trace fossil Daedalus occur sporadically near the top of the sandstone ledge. Detailed regional correlation by Duke and Fawcett (1987) indicates that this unit is the equivalent of the Thorold Sandstone at the Niagara Gorge. The upper contact of the sandstone is marked by a thin red silty bed containing a "hash" of lingulid shell fragments.
The Thorold, in turn, is overlain by 1.7 to 1.8 m of dominantly red silty shale of the (Cambria Member) uppermost Medina Group. This shale bears distinctive fine, white mottling due to bioturbation. Although previously assigned to the Grimsby Formation, this is a distinctive, ostracode-bearing shaley unit that overlies the Thorold Sandstone and is traceable regionally at least as far east as the Rochester area. We informally identify this unit as the Cambria Shale Member of the Thorold Formation, using this section as the type locality.
The upper portion of the Cambria Member is pale purplish to greenish gray sandstone and sandy shale that was formerly termed Thorold Sandstone. In actuality, this is simply a leached sandy zone in the Cambria Shale. The Kodak Sandstone, observed at Stop 1B, and about 1 m of Cambria Shale, have been removed here at the sequence I/II unconformity. Sandstones contain small Skolithos burrows and intercalated green shale beds, especially the topmost layer, contain prolific leperditiid ostracodes. The greenish color extends down about 30 to 50 centimeters below the upper contact where sandstones are mottled pale purple and green. This discoloration is probably associated with the top unconformity and deposition of overlying reducing sediments (Duke et al., 1987). Here, as at the Lockport railroad cut, the top of the Medina Sandstone is an erosion surface overlain by a thin (3 to 5 centimeter) dark gray, phosphatic sandy limestone (Densmore Creek Bed) with prolific Hyattadina brachiopod valves. A thin laminated siltstone rests on the bed at the contact with the greenish gray Neahga Shale, which at this locality is about 1.0 meter thick--substantially thicker than at Lockport (STOP 1B).
At the base of the Hickory Corners Limestone (Reynales) is a thin (3 to 5 centimeter) pyritic, sandy limestone packed with black phosphatic pebbles and shell fragments (Budd Road phosphatic Bed). It is overlain by about 40 centimeters of alternating greenish gray shales and thin limestones capped by a 60 centimeter thick ledge of nodular crinoidal pack- and wackestone at the top of the roadcut. These beds contain a prolific fauna including corals, brachiopods (Hyattidina, Dalejina, Platystrophia) and pentameric crinoid stems belonging to a newly described inadunate. The upper surface at this locality is a glacially striated pavement and the post-Reynales erosion surface cannot be observed.

STOP 2B: Lockport Junction Roadcut (Upper)
(Upper Rochester, Decew, Gasport Formations)
This large roadcut displays the upper part of the Rochester Formation (about 5 meters), DeCew Dolostone (2.5 meters), and Gasport Limestone (over 7 meters); it was described in detail as Stop 1 of Brett's (1982) NYSGA Guidebook article. However, since that time the exposure has been freshly blasted to widen Route 93. A subsequence boundary occurs between the dolomitic calcisiltites and shales of the upper Rochester Shale and the overlying DeCew Dolostone. The latter is a buff-weathering, silty dolostone with thin layers of intraclasts and contorted bedding. The basal contact is sharp and locally channeled, but nearly conformable. The upper Rochester and DeCew are burrowed in some levels; body fossils are rare but this exposure has produced long columns of crinoids in the lower DeCew.
The sharp and undulatory upper contact of the DeCew Dolostone with the Gasport Formation forms the boundary between the Clinton and Lockport Groups, and is interpreted as a sequence bounding unconformity (between sequences V and VI). The surface represents an abrupt lowering of relative sea-level and beveling of older strata. The basal Gasport bed is a greenish gray brachiopod-rich, crinoidal grainstone conglomerate with dolostone clasts eroded from the DeCew. Missing at this contact is the newly recognized Glenmark Shale, a fossiliferous gray shale with litho- and biofacies resembling the Rochester Shale .
Only the lower (Gothic Hill) member of the Gasport is present here. At this locality and at cuts along adjacent Gothic Hill Road this unit is exceptionally thick (7-8 meters) and composed of well to poorly sorted pelmatozoan pack- and grainstones. This facies is interpreted as a high energy crinoidal bank. Brachiopods are common in an argillaceous, thin-bedded unit near the top of the unit. A small bioherm composed of algal and bryozoan boundstone (micrite) occurs within the Gothic Hill Member. The overlying units will be examined at the next stop.

Exposures of fossiliferous Rochester Shale along Thrall Road
Exposures of fossiliferous Rochester Shale along Thrall Road were described as Stop 2 in Brett (1982).

STOP 3: Pekin Hill (Route 429) Road Cut At Underpass
Beneath Upper Mountain Road. (Gasport-Goat Island Formations).
This classic exposure, described in detail by Crowley and Poore (1974), displays biohermal structures characteristic of the lower Lockport Group. Although the exposure is becoming overgrown, it has been restudied recently as part of our stratigraphic revision.
The lowest stratum, barely visible in the northernmost end of the outcrop (east side of road) is a crinoidal grainstone which marks the top of the Gothic Hill Member (seen at the last stop). The crinoidal grainstone is overlain on the east side of the road cut by approximately 4 to 5 meters of thin-bedded, bioturbated argillaceous dolostone which Brett et al. (in prep) refer to as the Pekin Member of the Gasport Formation. A small bioherm, "rooted" in the underlying Gothic Hill Member, protrudes upward into the sparsely fosssiliferous Pekin Member on the west side of the road cut.
Of particular importance is the sharp upper contact of the Pekin Member with pink, fine-grained crinoidal and cladoporid coral -bearing dolomitic grainstones of the basal (Niagara Falls Member) of the Goat Island Formation on the east side of the road. This contact can be traced to near the concrete wall for the Upper Mountain Road overpass. Here, it is seen to drop in elevation, apparently defining a channel-like feature that underlies stromatoporoid-rich biohermal dolomicrites. The latter appear to laterally replace the pink grainstone facies of the Goat Island.
On the west side of the road, the main mass of the bioherm described by Crowley and Poore (1974) can be seen. It is evidently a continuation of the biohermal mass seen near the bridge footing on the east side. This bioherm appears to occur above the sharp and distinctly irregular contact of the Goat Island Formation. Again, this contact is channelized into the dark, argillaceous dolostones of the underlying Pekin Member. Hence the so-called "Gasport bioherm" at this locality appears to be a biohermal mass within the lower Goat Island Formation.
The bioherm consists of dolomicrite containing very abundant, large stromatoporoid heads, many of which are reoriented or overturned and hence, are not preserved in situ. Near the center of the biohermal mass, the dolomicrite facies passes abruptly into pale pinkish gray fine- grained grainstone, closely resembling the non-biohermal basal Goat Island facies on the east side of the road. The pale gray "reefy" dolomicrite facies appears both north and south of the grainstone pocket which appears to have filled the center of the large channel-like feature cut into the top of the Pekin Member. Also note two or more sharply defined surfaces within the biohermal masses that may represent minor erosion surfaces. Overall, we interpret the bioherm here as a possible bank of algally (?) bound micrite and stromatoporoids (and a few tabulates) that lined a (storm surge?) channel cut into the muddy carbonates of the Pekin Member. The center of the channel was occupied by fine carbonate sand but was eventually "overrun" by the biohermal facies developing inward from the two channel margins. The channel itself was apparently oriented NW/SE, roughly perpendicular to regional facies strike. The erosion of the Pekin Member mudstones may have occurred during a relative sea-level lowstand that marks the boundary between Gasport and Goat Island depositional subsequences. (For a radically different interpretation of the stromatoporoid facies as a late successional stage of a Gasport bioherm, see Crowley, 1973, and Crowley and Poore, 1974).
The outcrop continues south of the Upper Mountain Road bridge. Here the upper portion of the stromatoporoid biohermal mass is abruptly overlain (contact now obscured) by thin-bedded, fine-grained, buff-weathering dolomicrite with bands of white chert nodules. We refer to this facies as the middle or Ancaster Member of the Goat Island Formation. Note a distinctive marker bed of silicified Whitfieldella brachiopods. The cherty facies records a general deepening trend in the upper Goat Island. It is somewhat comparable to the Pekin Member of the Gasport, but the latter is not cherty.

Niagara Air Force Base on
left.

STOP 4: Niagara Stone Quarry (Lockport Group)
This active quarry provides the most complete section of the Lockport Group in the Niagara region. Aspects of the jointing and hydrogeology of the Lockport at this locality are discussed in detail in the contribution by Tepper et al., this guidebook). We will briefly examine the overall stratigraphy focusing on the Goat Island Formation. The section extends from the top of the DeCew Dolostone and its unconformable contact with the overlying Lockport Group (sequence V/VI boundary) to beds near the base of the Guelph Formation at the quarry rim. The lower Gasport limestones-appear to fall in the sagitta conodont zone making them late Wenlockian in age. Furthermore, recent graptolite discoveries indicate that the Wenlockian/Ludlovian boundary lies close to the Gasport/Goat Island contact (LoDuca and Brett, in press). Kleffner (1989) obtained siluricus zone conodonts from the upper Eramosa beds here.
The DeCew Dolostone is observable in the deepest part (lowest lift) of the quarry where it exhibits a contorted upper surface and internal hummocky cross-stratification. The sequence bounding unconformity between the DeCew and the Gasport Formation of the Lockport Group is marked by a thin, greenish (glauconitic) grainstone containing rip-up clasts of DeCew Dolostone up to 10 centimeters across. The lower or Gothic Hill Member of the Gasport is a massive, 5 meter thick interval of light pinkish gray, commonly orange weathering, crinoidal grainstone. The overlying Pekin Member is a 5 meter-thick interval of thin to medium-bedded, medium gray argillaceous dolostone . A bioherm extends up through the interval in the northwest corner of the deep pit.
The lower Goat Island (Niagara Falls Member) can be examined along the top of the ramp road leading to the lowest pit of the quarry, although the basal contact with the Pekin Member is obscure and inaccessible. The upper 1.5 meters of the Niagara Falls Member is a distinctive interval (Niagara Falls C unit) consisting of very dark gray, vuggy dolostone with distinct, white weathering stromatoporoids and corals. These and immediately underlying beds reflect a relative sea-level lowstand corresponding to the biohermal bed of Pekin cut. Beds overlying the Niagara Falls Member are assigned presently to the Ancaster and Vinemount Members of the Goat Island Formation. Both of these units have their type sections near Hamilton, Ontario.
The middle Goat Island interval is well developed in the walls above the second lift. The platform below is bulldozed off on a surface within the Ancaster Member. Thin flaggy beds of pale buff-weathering, fine-grained dolostone in the lower half meter of contain the chert nodules that characterize the Ancaster Member in its type area. However, the overlying interval is medium to thick-bedded, buff colored, medium-grained and generally noncherty dolostone. A distinctive layer of silicified and valves of Whitfieldella brachiopods occurs about 1.5 meters above the second lift. This layer may correlate with the Whitfieldella bed seen at the Pekin road cut (Stop 3).
Ancaster facies are interpreted to represent a similar offshore, low energy shelf environment. The abundance of chert in the Ancaster is unique among the Silurian units in the Niagara region; the cherts may reflect the availability of biogenic silica from the abundant sponges which occupied the seafloor at this time, although this is probably not a complete explanation.
The uppermost half meter of the Ancaster Member is marked by numerous vugs that appear to represent small corals and stromatoporoids. This bed is abruptly overlain by a layer of dark gray dolomitic shale that marks the base of a 3 m-thick bituminous argillaceous unit. Detailed outcrop and subsurface tracing of the unit indicates that it is coextensive with the Vinemount shale beds of the Hamilton, Ontario region. These argillaceous beds appear to grade laterally and vertically into Ancaster cherty dolostone beds and hence both are assigned member status in the Goat Island Formation. The Vinemount here comprises about 3 meters of dark gray, bituminous and argillaceous dolostone with some shale partings. Fossils are rare and poorly preserved, but include rhynchonellid and atrypid brachiopods, small rugose and favositid corals and the large nautiloid Dawsonoceras.
Together, the three members of the Goat Island Formation comprise an upward deepening (retrogradational) subsequence. It is marked at the base by an erosion surface between the Pekin Member of the Gasport Formation and the Niagara Falls Member of the Goat Island. The top of the Niagara Falls Member constitutes a marine flooding surface. Cherty beds of the basal Ancaster reflect relatively slow deposition during the early highstand.
The upper quarry walls above the Vinemount display the entirety of the Eramosa Formation (formerly called Oak Orchard Member; see Zenger, 1965). Recent work (Brett et.al., in press) indicates that "Oak Orchard" is an invalid term since the highest unit is exposed on Oak Orchard Creek is equivalent to the Vinemount beds. Furthermore, tracing of key units into Ontario indicates their correlation with the Eramosa and lower Guelph Formations in the type areas of Canada.
A number of informal units are recognizable within the Eramosa and are visible in the wall. Lowest is a 1.8 meter thick, massive, biostromal bed containing white gypsum filled vugs. This is succeeded by a rather nondescript, fine- grained facies 3.5 m which, in turn, is overlain by biostromal or thrombolitic dolomicrite. Notable are the two flaggy-weathering intervals at the top and base of this zone that may represent minor discontinuities. Toward the top of the quarry are 6 m Eramosa Formation, containing large, lenticular stromatolitic bioherms observable in the south wall .
Overlying units, at or near, the quarry rim are about 1.5 to 2.0 m of biostromal brownish gray dolostones with very abundant Favosites corals some of which are infilled by purple fluorite. The topmost bed in parts of the quarry is a light gray-weathering, stromatolitic (LLH) dolostone which forms a regional marker.
The Eramosa interval appears to represent an upward shallowing succession (subsequence) reflecting late highstand conditions.

STOP 5A. Robert Moses Access Road And Forebay
(Upper Lockport Group)
Higher units of the Lockport Group are visible along the fore bay and access road to the Robert Moses Power Plant, just west of Military Road and 0.9 miles north of Route 31. Here we will briefly examine, from a distance, exposures in the forebay canal of the upper Eramosa (new usage in New York) and lower Guelph Formations. Note the large algal bioherms which characterize the uppermost units of the Eramosa Formation in Niagara County (seen at Stop 4). The highest units in the forebay canal are more or less tabular stromatolitic dolostone which are, at present, assigned to the basal beds of the Guelph Formation (Fig. 16). Exposures in the small road cut at the underpass of the access road beneath the lanes of I-190 contain exceptionally large stromatolites. These strata represent a very distinctive marker horizon in the basal Guelph beds in western New York. The stromatolite heads are approximately 2 meters across but superimposed on these are small digitate upward growths of stromatolitic boundstone. The stromatolitic horizon is thought to be traceable at least to Hamilton where it comprises the basal transition bed between the Eramosa and Guelph.

STOP 5B: North End, Niagara Gorge
Between Lewiston-Queenston Bridge And Robert Moses Power Plant (Clinton Group)
Park vehicles near small building on right. Proceed on foot through railroad underpass (under Route- 104). At far end turn left, walk up slight embankment then down other side to exit lanes onto Robert Moses Parkway. Turn left and walk across exit lane and carefully cross two lanes of Rober Moses Parkway. At 55 mph sign step step over guard rail and down a slope bearing right (north) to cliffs along Niagara Gorge. (Note: permission should be obtained from Niagara Parking Commission for access to this stop.)
The Rochester Shale in this cliff exposure along the east face of Niagara Gorge was described in detail by Brett (1982). It provides an excellent section of the entire Clinton and Lower Lockport units. It also provides excellent fossil collecting in the Rochester Shale.
Proceed down to a small ditch in the gorge nearly opposite the Irondequoit-Rochester contact in the main cliff exposure. At its base, this gully exposes orange-weathered Thorold Sandstone, overlain by a thin (about 0.5 m) maroon and pale green sandy shale situated beneath the Neahga Shale. This is the last vestige of the Cambria Shale. To the south and west it has been lost to pre-Neahga erosion. A thin, Hyattidina- bearing, calcareous sandstone (Densmore Creek Bed equivalent) occurs at the base of the Neahga Shale. The latter is about 2 meters thick, dark gray, fissile gray shale. The overlying Reynales Limestone with a thin basal phosphate bed (Budd Road Bed) is nearly identical to that seen at Lockport Junction Roadcut (Stop 2). Note thick, nodular, coral-bearing packstone at the top.
Exposures in the main wall of the gorge show the basal contact of the overlying Rockway Dolostone. A 10-15 cm phosphatic, black shale resting on the Reynales represents a thin tongue of the Williamson Shale. This contact is sharp and represents a major unconformity at which most of the lower and middle Clinton units have been beveled (compare STOP 1B).
The overlying Rockway Member (of the Irondequoit Formation, Kilgour, 1963) is a buff-weathering, argillaceous dolostone with thin shales. The Rockway shows prominent bands, ranging from a few centimeters to half meter thick, of argillaceous dolomite, which are interbedded with thin green shales. These two interbedded facies define a small scale cyclicity which can be traced on a regional basis. Rockway beds apparently record relatively sediment starved, off-shore marine lime and siliciclastic muds. Extensive dolomitization has obscured the fossil content of this unit. However, large brachiopods (Costistricklandia) are locally abundant, particularly in the middle thick bedded unit of the Rockway. Dendroid graptolites, rare favositid corals and nautiloids fossils are occasionally found. On the basis of conodont biostratigraphy, the Rockway belongs to the upper part of the amorphognathoides zone (latest Llandovery to earliest Wenlock Series).
It should be noted that the rock, here termed Rockway Member of the Irondequoit Formation, whose type section is in Canada (15 Mile Creek at Rockway, Ontario), is commonly referred to as the upper beds of "Reynales" limestone by Canadian geologists. However, the Sequence IV boundary unconformity, cuts out the true Reynales Limestone just west of the Niagara Gorge. Hence, the true Reynales is absent in Canada, except along the Niagara River.
A sharp contact separates the Rockway from the overlying massive, crinoidal grainstones of the upper (Model City) member of the Irondequoit. Clasts of fine-grained dolostone derived from the underlying Rockway occur in the basal thin bed of the Model City.
The upper member of the Irondequoit Formation (Model City Member of Brett et al., in press), consists of massive, pinkish-gray, crinoidal limestone and dolostone which rests with the sharp and slightly disconformable surface on the upper shaley, beds of the Rockway Member (Subsequence IVB). In places a thin phosphate or pyrite crusted surface delimits the upper surface of this 6 inch band. This pyritic crust probably marks a hardground. The Model City member shows a minor trend of upward deepening toward the top and a conformable, although abrupt, contact with the overlying Rochester Shale. Faunal density is interpreted as representing a shallow, highly agitated (near wave base) crinoidal shoal environment; brachiopod assemblages suggest a benthic assemblage-(BA) 3 paleobathymetry. Conodonts indicate an earliest Wenlockian age.
The Model City in turn, is interpreted as a transgressive systems tract of subsequence VA (Fig. 15). Its sharp upper contact with the Rochester Shale, which is locally glauconitic, is considered to be a surface of maximum starvation (marine flooding surface). In the cliff opposite the small ditch (which exposes the Thorold-Reynales) a small micritic (algal?) bryozoan bioherms protrude from the top of the Model City into the overlying Rochester Shale.
The overlying Rochester Shale, which is about 18 m thick, is a gray calcareous to dolomitic mudstone with numerous thin carbonates representing shell-rich and carbonate-silt storm deposits (Fig. 15). It can be examined by walking south along the base of the cliff toward the Robert Moses Power Plant. Though the Rochester initially appears homogeneous, it shows a distinct internal cyclicity which is traceable very widely. Most notable is the medial band of bryozoan-rich carbonates that occurs about 9 m above the base of the Rochester Shale. The sharp top of this unit has been used to demarcate the boundary between the Lewiston and Burliegh Hill Members of the Rochester Shale (Brett, 1983).
The Lewiston Member itself displays an alternation of fossiliferous limestones and calcareous shale intervals with nearly barren shale. Bryozoan rich beds occur up to about 10 feet above the base (Lewiston B unit). This fossiliferous unit is followed by a barren shale zone containing only thin calcisiltites (Lewiston C). This barren unit, in turn, gives way upward to bryozoan rich mudstones and finally, bryozoan pack- and grainstones (Lewiston D and E; Fig. 14). These facies alternations are interpreted as defining small scale cycles (parasequences).
The overlying Lewiston E limestone appears to be a weak signature of a relative sea-level fall and subsequent transgression. In short, a relative sea level drop followed by a rather rapid sea level rise is envisioned for this portion of the section (Fig. 2). Although no erosion or even sharp surfaces are seen at the base of the Lewiston E bed at Niagara Gorge, as this bed is traced westward onto the Algonquin Arch, it shows an increased sharpness to its base and, eventually, an erosion surface beneath the Lewiston E truncates most of the beds of the lower Lewiston. The upper surface of the Lewiston is sharp and locally glauconitic, and shows an abrupt change to the barren dark gray Burleigh Hill shales. This contact, again, is interpreted as a surface of relative sediment starvation, or marine flooding surface, associated with increased rates of sea level rise. The Burleigh Hill shales are largely barren of fossils and show relatively few interbeds, except in the upper third, where the unit becomes silty and contains some thin fossil stringers (Fig. 7). The member on the whole is considered to be an upward shallowing or regressive cycle (highstand deposit). As such, it can be interpreted as representing highstand conditions with minor progradation of carbonate silt toward the end of Rochester Shale deposition. The contact with the overlying DeCew Dolostone may locally appear sharp or gradational. A minor diastem is likely and subsequence boundary is placed at the bottom of the DeCew dolostone, but no major sequence bounding unconformity occurs at this surface.
The DeCew is an interesting 9 m thick, blocky dolostone which shows spectacular soft sediment deformation. The deformation may be interpreted as a response to single event, possibly a seismite associated with early pulses of tectonic activity during the onset of the Salinic Orogeny in eastern New York. Shaley beds of the DeCew are present locally along Niagara Gorge but have been removed in most areas seen on this trip.
The base of the Gasport crinoidal grainstone also seen at STOP 2B, is similar to the base of the Model City grainstone in that it contains rip-up clasts of dolomitic, argillaceous dolostone derived from the underlying, finer grained unit. To the west, this erosion surface removes the DeCew entirely in the vicinity of Hamilton, Ontario and further cuts out the upper beds of the Rochester Shale northwest of Hamilton. The lower Gasport Gothic Hill Member shows spectacular small scale trough and planar cross stratification. Some of this bedding appears to be bipolar, possibly indicating the influence of tidal currents. Like the similar Irondequoit grainstones, the lower Gasport grainstone is interpreted as an amalgamated crinoidal shoal deposit consisting of multiply reworked pelmatozoan sand and gravel. No Pekin Member is present here. Instead, a 2 meter thick vuggy, stromatoporoid-bearing dolostone (basal Niagara Falls Member A) of the Goat Island Formation rests directly on the Gothic Hill (lower Gasport) grainstone. Overlying beds, largely inaccessible, consist of bluff dolostone and tan cherty dolostones (Ancaster Member).

STOP 6: South Haul Road To Robert Moses Power Plant
Parking area for fisherman on left. Pull in and park. We will proceed on foot down the south haul access road for about 0.3 miles to the fishing area near the bottom of the gorge.
Please note: access to this section must be obtained from the Power Authority; hard hats are required and collecting is not permitted,
This outstanding outcrop, arguably the most complete Silurian section in New York State, provides an opportunity to summarize and review all of the points of the preceding trip.
The section begins with about 8 m of the upper Ordovician Queenston Shale. Its sharp contact with the overlying Whirlpool Sandstone is the Silurian sequence I boundary. The Whirlpool, here as at Lockport (Stop 1); is represented by channel facies which record a nonmarine to marine transition. Minor phosphatic material occurs at the upper contact (starvation surface, or marine flooding surface) with the Power Glen.
The Power Glen is both thicker (8 m) and shalier at this locality than the section seen at stop 1. It is entirely gray shale, lacking the upper reddish sandy zone seen at Lockport.
As at Lockport, the Power Glen is overlain by a 2 meter thick massive white quartzose sandstone (Devil' s Hole Member of Duke et al., in press), the base of subsequence IB of the Medina Group. Overlying (lower Grimsby) shales here are green and fossiliferous, in contrast to the red, ferruginous, lingulid shales seen at Lockport. The locality represents a more offshore section.
At the north end of Niagara Gorge a distinct, meter-thick phosphatic sandy dolostone, the Artpark Phosphate Bed, occurs in this position. Here, only minor phosphatic sandstone overlies the "Devil's Hole" Sandstone. These beds and the ferruginous zone at Lockport constitute a condensed section associated with rapid sea-level rise.
The main body of the Grimsby Formation (about 15 m thick) is red shale with thin sandstones. Three or four small-scale shallowing upward shale to sandstone cycles have been recognized by Duke et al. (1987) in this interval. This section is one of the most shale-rich exposures of the Grimsby in Niagara County. Sections both north and south of this locality contain more channel sandstones.
The upper beds of the Medina Group comprise about 2 meters of white, crossbedded Thorold Sandstone. The Thorold has a sharp erosive base which marks the base of the next Medina subsequence. Overlying Cambria Shale, seen at stops 2 and 5, is completely missing here. The sandy phosphatic Densmore Creek Bed rests sharply on the Thorold, marking the sequence I/II boundary.
The Neahga Shale is poorly exposed but is about the same thickness as at stop 5 on the north side of the power plant. The two phosphatic beds of the basal Reynales Limestone and the nodular capping bed are nearly the same as in the other sections seen in Niagara County. A prominent black phosphatic staining occurs on the upper surface of the Reynales Limestone (see near one of the protective cages on the outcrop). This stained surface is the sequence II/IV contact.
The Rockway/Model City (sequence IV/V boundary) is also well displayed. No bioherms occur here at the upper contact of the Irondequoit Limestone with the Rochester Shale, but a 30 centimeter thick shell bed marks the condensed zone. The lower Rochester Shale is partly obscured by a protective cage (toxic chemical seep?), but upper limestone beds of the Lewiston Member are well exposed. Overall the Lewiston Member is somewhat less fossiliferous and contains fewer limestone beds than at stop 5, just on the north side of the power plant. This loss of interbeds reflects the beginning of a major facies change into sparsely fossiliferous Rochester Shale southward along Niagara Gorge (see Brett, 1982).
The upper Rochester displays a sharp contact with the enterolithic DeCew Dolostone beds, herein interpreted as the basal unit of a partially eroded upper Clinton subsequence. The sequence V/VI boundary at the DeCew/Gasport contact is well exposed near the entrance to the "tunnel" beneath the Robert Moses Parkway at the top of the cut. Weathered surfaces of the Gothic Hill grainstones display probable bipolar cross-stratification. In contrast to the cut on the north side of the power plant (stop 5) some 2.5 meters of argillaceous upper Gasport (Pekin Member) strata are present here. These beds display a sharp undulatory contact with overlying vuggy dolostones of the Niagara Falls Member of the Goat Island Formation. The base of the Niagara Falls Member is a subsequence boundary which erosionally bevels the 2.5 meters of Pekin Member strata between the two sides of the power plant.
As a whole, the Gasport Formation comprises a complete subsequence. The basal crinoidal grainstones of the Gothic Hill Member represent transgressive systems tract deposits, the contact with the Pekin Member is a marine flooding surface and the Pekin muddy carbonates represent relative highstand deposits (Fig. 15). This subsequence is analogous to the Model City - lower Rochester Shale subsequence.
The dark, argillaceous dolostones of the upper Gasport Formation are sharply and erosionally overlain by basal medium-bedded dolostones of the Goat Island Formation (Fig. 16). This erosional contact is the same one observed at Pekin Roadcut (Stop 3). These dolostones, in turn, are overlain by massive, dolomitic, crinoidal grainstones appear at the type section of the Goat Island Formation at the brink of Niagara Falls. The south haul road section is a reference section for the lower portion of Goat Island Formation (Zenger, 1965). The unit is crinoidal and contains scattered Cladopora corals and stromatoporoids. Upper beds of the Niagara Falls Member display abundant vugs which appear to be solution cavities in a stromatoporoid-rich zone. This layer is locally highly biostromal, as noted at Niagara Stone quarry (STOP 4).
The Ancaster Member is poorly developed compared to that seen at Niagara Stone quarry (STOP 4), thin (-2.5 m) and only sparingly cherty. However, in the cliffs immediately north of the Robert Moses Power Plant, this member is developed in its typical thick cherty phase. There appears to be a complementary relationship, in terms of thickness, between the Niagara Falls Member and the overlying Ancaster Member; i.e. where the Niagara Falls Member is thick, the Ancaster is thin to nonexistent and vice versa. Argillaceous gray dolostones of the Vinemount Member form the uppermost unit on the access road.
The Goat Island Formation as a whole here appears to be a "twin cycle" to the Gasport. The lower or Niagara Falls grainstone member constitutes the transgressive portion; its sharp boundary with the overlying Ancaster Member is a surface of starvation, sometimes recorded in the relatively glauconitic cherty beds of the lower Ancaster (Fig. 16). Ancaster and Vinemount Members represent highstand deposits.

SatD: EURYPTERID BIOFACIES OF THE SILURIAN-DEVONIAN EVAPORITE SEQUENCE: NIAGARA PENINSULA, ONTARIO, CANADA AND NEW YORK
For the past 28 years, I have been studying eurypterids, their stratigraphic occurrence, distribution, and associated flora and fauna, particularly in northeastern United States and Ontario, Canada. In New York the best known eurypterid assemblages are: 1) the Eurypterus remipes Fauna of the Fiddlers Green Formation that includes the earliest discovery of an eurypterid on this planet (by Dr. Mitchell in 1818); 2) the younger Eurypterus lacustris Fauna of the Williamsville Formation of western New York and Ontario, Canada; and 3) the eurypterid fauna of the Shawangunk Formation southeastern New York.
The search for new eurypterid faunas and the study of their geographic distribution in the Siluro-Devonian rocks of the region is important for several reasons. Foremost is the fact that the eurypterid faunas are punctuated within the known stratigraphic sequences. New genera appear suddenly within the sequences, e.g. Waeringopterus Zone, Erieopterus Zone, etc. When an eurypterid species disappears from the record completely, it is easily understood and we often assume extinction. The sudden appearance (or ecological replacement) of a species by an unrelated forms, (such as the Silurian Eurypterus being replaced by Erieopterus in the Early Devonian, is much more difficult to decipher. Only continued search for intervening occurrences, stratigraphically and geographically, will provide the data needed to understand the evolution of the eurypterids and their assemblages.
A second factor of significance concerns the eurypterid assemblages. Generally, where eurypterids are found there is a conspicuous absence of other fossils, in number and especially in diversity. Hence, the stratigraphic sequence is often considered to be unfossiliferous. The evaporite-bearing Salina Group is notable of this designation. Precise correlation, regionally and inter-regionally is needed to achieve a more complete understanding of these unique invertebrates. See Figure 1 for a map showing areas having exposures of Late Silurian-Early Devonian strata.

SatD: EURYPTERID BIOFACIES OF THE SILURIAN-DEVONIAN EVAPORITE SEQUENCE: NIAGARA PENINSULA, ONTARIO, CANADA AND NEW YORK

STOP 1. Ridgemount (Campbell) Quarry
Camillus Shale or Oatka Shale forms the quarry floor. Above this is a thin representation of the Morganville Waterlime followed by massive beds of the Victor Dolostone. Several feet of Ellicott Creek Breccia are accessible on the northeast side of the quarry and from this many eurypterids have been obtained (Ciurca and Gartland, 1976). The higher strata, including the Williamsville Waterlime, are all visible in the quarry walls. The Devonian Bois Blanc Formation is particularly fossiliferous in this quarry.

STOP 2. Welland Canal Underpass Roadcut
SYRACUSE FORMATION (SALINA GROUP). A portion of the Syracuse Fm. is well exposed exhibiting gypsum beds, fine-grained dolostone replete with cavities formed by dissolution of evaporites. Crude algal mounds are present and the facies developed here is identical to that displayed in the type area in central New York.
Waeringopterus, characteristic of the lower or transitional beds of the Syracuse Fm., occurs here in the argillaceous dolostones.

STOP 3 Quarry At Byng
The Bertie Group is prominent in the lower portions of the quarry. Particularly important is the sequence above the Cobllekill Formation at this site. The Clanbrassil Formation makes its appearance beneath the unconformity at the base of the Bois Blanc Formation. In this quarry the Clanbrassil Fm. consists primarily of waterlimes, i.e. very fine-grained dolostones having conchoidal fractures. The only fossil obtained from the Clanbrassil Fm. at this locality is Erieopterus.

STOP 4. Cayuga Quarry
This large quarry complex contains an important section including the Williamsville Waterlime and the Clanbrassil Formation. Erieopterus seems to be more common in the Clanbrassil Fm. and in the quarries at Haggersville.

STOP 5. Abandoned Quarry
Type section Clanbrassil Formation. The Clanbrassil Formation occurs in the walls of an abandoned quarry at the Stone Crest Farm.

SatE: UPPER DEVONIAN TURBIDITES IN WESTERN NEW YORK: CHARACTERISTICS AND IMPLICATIONS FOR SUBMARINE FAN DEPOSITION MODELS
ROBERT JACOBI
Department of Geology; SUNY at Buffalo; 4240 Ridge Lea Rd; Buffalo, NY 14226
MICHAEL GUTMANN
URS Consultants; 570 Delaware; Buffalo, NY 14202
AL PIECHOCKI
SUZANNE O'CONNELLv Department of Earth and Environmental Sciences; Wesleyan University; Middletown, CT 06457
JILL SINGER
Department of Earth Sciences; State University College at Buffalo; 1300 Elmwood Ave.; Buffalo, NY 14222
CHARLES MITCHELL
Department of Geology; SUNY atBuffalo; 4240 Ridge Lea Rd; Buffalo, NY 14226
STEVE FRANK
DAVID SCHEUING
Lamont-Doherty Geological Observatory and Department of Geological Sciences; Columbia University; Palisades, NY 10964
STEVE HASIOTIS
The object of this field trip is to acquaint you with some of the characteristics of Upper Devonian turbidites in western New York* (WNY). We will examine three coarsening-upward clastic depositional cycles within the West Falls, Perrysburg and Java formations. The many gorges and ravines in WNY provide the control necessary to trace individual sandstone beds across the region, allowing us to characterize their interrelationships and their lateral variability in bedforms, texture, and thickness. From these and other data we believe the WNY turbidites in this part of the sequence represent lobe fringe and sand lobe deposition on a submarine fan. Continued study of these turbidites will help resolve problems encountered in both modern and ancient submarine fan research. Construction of a depositional model based on this research will entail 1) deposition and flow characteristics for individual non-channelized turbidity currents, 2) relationships, among various fan elements, and 3) fan vs. clastic ramp development. A more detailed discussion of the research rationale and results is presented in Jacobi et al. (in press)

SatE: UPPER DEVONIAN TURBIDITES IN WESTERN NEW YORK: CHARACTERISTICS AND IMPLICATIONS FOR SUBMARINE FAN DEPOSITION MODELS

Bridge crossing the South Branch of 18 Mile Creek.
Excellent exposures of Java Formation shales on the left.

Bridge crossing the South Branch of 18 Mile Creek.
The contact between Java Formation shales and the overlying Dunkirk Shale Member of the Canadaway Formation is exposed near the base of the section to the left. For permission to inspect outcrop, ask owners at house along the creek (driveway to the west of bridge)

Waterfall in creek to the right of road.
Falls is in the Dunkirk Shale. In periods of summer overgrowth, the falls can be viewed from the bridge on Clarksburg Rd., 0.07 mi. back

STOP 1. Creek bed near a sharp turn to left on New Oregon Rd.
For permission to view outcrop, ask owners at the second house past barn along the turn and also ask at the house on the left past the private bridge on the driveway to the outcrop (Fig. 8)
Walk down the driveway toward the private bridge over the South Branch Eighteen Mile Creek. The creek bed directly below the bridge, as well as the creek bed upstream, (south) displays a "typical" exposure of the South Wales Shale Member of the Perrysburg Formation. The stratigraphic column for the South Wales Shale Member at this locality is portrayed in Figure 3. The contact between the basal sandstone of the South Wales Shale Member and black shales of the Dunkirk Shale Member is exposed at the waterfall north (downstream) of the bridge. The upper surface of the basal bed (exposed directly beneath the bridge) displays prominent straight to sinuous-crested ripples (Bouma Tc). The sandstone bed that forms the cap rock of the waterfalls upstream (south) from the bridge also shows prominent ripples, as well as orthogonal grooves.

View of upper portion of the South Wales Shale Member
View of upper portion of the South Wales Shale Member of the Perrysburg Formation on the right.

View of waterfall on right from bridge.
This falls is also in the Dunkirk Shale Member of the Perrysburg Formation.

STOP 2. Much of the ravine on the south of road.
For permission to view outcrop, ask owners at: 10983 Blanchard and also at two homes at Route 16 (see road log below and Fig. 8).
This stop consists of much of the ravine (indicated on Figure 8) south of Blanchard Road. We will walk south from the parking site to the ravine via farmers' roads, then logging roads, and finally deer trails. We will walk down (east) the ravine and come out on Rte 16. This stop displays a complete section from Nunda Sandstone Member at the base near Route 16 to South Wales Shale Member near the top of the ravine. We will hand out a measured section of this locality on the field trip. In the South Wales Shale Member section, notice that the basal sandstone is no longer prominently rippled, unlike the same sand at STOP 1 to the west; rather, it is massive to planar bedded (Bouma Talb). The transition from rippled to massive/planar occurs between this section and that exposed at optional stop 3. In the Nunda Sandstone Member note the escape burrows (vertical worm burrows) and undulatory bedding.

STOP 3. (optional)
To view outcrop, ask owners' permission at 11025 1/2 Blanchard Rd. The owners need proof of self insurance or a signed statement releasing them of all responsibility.
Walk south from the A frame house (west of the owner's house) to the waterfall in the ravine that is closest to the Blanchard Road. This stop displays a fairly complete section of the South Wales Shale Member. Although we are about 22 km east-northeast of STOP 1, the general appearance of the sandstone beds in the South Wales Shale Member remains the same as that at STOP 1, including the prominently rippled basal sandstone.

Residence of landowner on right for permission to view Stop 2.

Residence of landowner #3 on right for permission to view Stop 2

STOP 4. (optional)
For permission to view outcrop, ask owners at house adjacent to creek section (1437 Mill Rd). The owners need proof of self insurance or a signed statement releasing them of all responsibility (Fig. 9).
This stop displays the upper sandstone of the Nunda Sandstone Member along the north wall of the ravine immediately west of the road. Note that its appearance (e.g., thickness) has not changed significantly from the Nunda exposed at STOP 2, some 10 km to the southeast. However, this sandstone bed abruptly pinches out about 3 km south of here (in a ravine 2 km south of here the sandstone is still a meter thick, but in an adjacent ravine at Pipe Creek 4 km south of here, the Nunda is nonexistent).

Bridge crossing the West Branch of Cazenovia Creek.
Exposures of the Angola Shale Member of the West Falls Formation are seen in the vertical cliff face to the right.

SatF: BEACH PROCESSES AND COASTAL MORPHOLOGY ALONG A RECURVED SAND SPIT: PRESQUE ISLE, PENNSYLVANIA
KENT TAYLOR and RAYMOND BOYCE
(Mercyhurst College)
Presque Isle is an 11 km long recurved sand spit on the south shore of Lake Erie partially enclosing Pennsylvania's only recreational and commercial shipping port, Presque Isle Bay and the City of Erie (Figure 1). A new $15 million system of detached breakwaters is presently under construction along the lake side of the Presque Isle beaches (Figure 2). The U.S. Army Corps of Engineers and the State of Pennsylvania are sharing the cost of this Shoreline Erosion Control Project. A great diversity of coastal engineering structures have been built along Presque Isle dating from the early 1800's to the present (Figure 3) and beach nourishment has been ongoing since 1955 (see Thomas and others, 1987, p. 33-38). The estimated cost of erosion control including beach nourishment from 1829 is $32 million, of which $20 million was spent since 1975. It is hoped that with the completion of the breakwaters the Presque Isle maintenance and nourishment costs will be reduced by $1 million per year for the next fifty years (personal communication Dale Hamlin, Pennsylvania Bureau of Water Projects, 1990).
The U.S. Corps of Engineers and the State of Pennsylvania have shared the responsibility of protecting Presque Isle from significant erosion. From the U.S.Corps of Engineers perspective the primary goal has been to ensure that the peninsula will continue to protect the Port of Erie. Only recently have the beaches on the lake side of the peninsula played a significant economic role for the City of Erie due to their immense recreational potential. Some conflicts have arisen recently between those who see the primary goal of erosion control projects as maintenance of recreational beaches and others who continue to pursue the long standing goal of harbor protection. Some progress has been made toward addressing both issues. One example is the recent spreading of a fine-grained sand layer over the beach replenishment materials selected for maximum cost effectiveness for erosion control (the so-called dirty sand and gravel taken yearly from upland gravel pits).

SatF: BEACH PROCESSES AND COASTAL MORPHOLOGY ALONG A RECURVED SAND SPIT: PRESQUE ISLE, PENNSYLVANIA

Overflight Departure Point

New condominiums on left.
Pile of large sandstone blocks is remains of 1948 vintage seawall, which was removed during condo construction.

Entrance to Presque Isle State Park.
Bike path leaves road on right.

View of Presque Isle Bay (Erie Harbor) to right.

Extensive swampy land.

Park headquarters building on right.

Niagara boat launch area on right.

Cookhouse Pavilion. Lunch Stop

Waterworks on right.

Experimental electric generating windmill on right.

STOP 1. Beach 6: Neck Segment
This stop is located to the west of Beach 6 between Groins 10 and 11 on the Neck segment of Presque Isle (Figure 11). Beach 6 is at the downdrift end of the groin field constructed to stabilize the Neck as part of the cooperative shore protection program beginning in 1954. This area is one of the erosional hot-spots along the peninsula's neck. Each year approximately 75,000 cubic yards of sand are dumped at this site as part of Presque Isle's annual beach nourishment program. This sand usually disappears by December after the intense storms in the fall.
Storm waves commonly arrive nearly perpendicular to this section of the Presque Isle shore. A large portion of the wave energy is transformed into storm water-level set-up against the beach. This results in a stratified current pattern with net lake-ward underflow along the bottom. During severe storms with strong winds from the southwest, high waves superimposed on elevated lake levels commonly wash over the roadways and sometimes entirely across the spit into the bay.
Within the groin field the nearshore slope is steep. Bar forms include an outer bar and an inner bar separated by a bar trough. The inner bar is linear or crescentic in form. The outer bar is crescentic with lows or saddles separating the 400-1000 m segments. The beaches within the groin field are narrow and generally erosional. Downdrift offsets of the beaches adjacent to the groins demonstrates the net west to east transport of sediment called littoral drift. Other engineering structures such as rip-rap revetments significantly influence the character of the beaches.
Results of a comprehensive nearshore current study and native-sand tracer study completed prior to breakwater construction on the inner bar system (Sonnenfeld, 1981) and the outer bar-trough system (Taylor, 1981) indicate the following nearshore dynamics for storm events (wave heights greater than 60 cm):
(1) Sediment from the beach and the inner bar is transported lake-ward towards the outer bar trough by rip currents located on the updrift sides of the groins, rip currents associated with cell circulation systems located between the groins and the net lake-ward flow near the bed.
(2) Sediment from the lake-ward flank of the outer bar and the bar crest is transported toward the trough inside the outer bar (outer-bar trough) in response to currents generated by incident waves shoaling and breaking on the outer bar.
(3) Sediment within the outer bar trough is transported by an eastward directed shore parallel current within the trough producing an effective mechanism for sediment bypassing the beaches downdrift of the source areas.
(4)Scouring within the outer bar trough is common during these conditions and results in an increase in the relief of the outer bar.
(1) What effect will the breakwaters have on sediment exchange between the beaches and the nearshore zone?
(2) What kinds of currents will be generated by the interaction of incident waves and the breakwaters?
(3) How much nourishment, if any, will be required to maintain the beaches?
(4) What will be the fate of the outer bar if offshore sediment transport is decreased?
THINGS TO LOOK FOR
* Notice wave height and approach direction with respect to the shoreline orientation.
* Notice longshore current direction and speed and look for evidence of rip currents (e.g. wave suppression in certain areas due to current outflow and suspended sediment plumes)
* Observe the texture of sediments including the beach replenishment materials.
* Observe the effects of engineering structures on beach morphology and wave reflection and refraction patterns.
* Notice the washovers in the backshore areas.
* Notice the newly constructed detached breakwaters. Can you see any difference in the beach behind the structures?
* Zebra mussels

Swampy area on right
Large number of dead trees due to high lake levels during the last several years.

Road to Marina and West Pier on right
Road to Marina and West Pier on right runs along an old dune ridge. It was the old park perimeter road before the 1956 dredging of nourishment material opened the Marina area.

Dunes and beach visible to left.

Entrance to park maintenance area on right.

Lighthouse (built in 1871) on left.
Sidewalk Trail trailhead on right. This concrete paved trail runs along the base of a dune ridge from the lighthouse to the bay shore near the East Boat Livery. It is shown on the 1900 15 minute topographic map, and was originally used as an access route for the lighthouse keepers, who crossed from Erie by boat. It was paved in 1913. The park road originally ran in front of the lighthouse, but was damaged by erosion in 1946, and relocated to its present position in 1948.

STOP 2. Beach 9: Lighthouse Beaches
This stop is located to the east of the lighthouse at Beach 9. The dramatically different morphology and dynamics along this section of the peninsula are a consequence of the change in shoreline orientation with respect to the dominant southwest wave approach direction and the influx of sediment eroded from the peninsula's neck.
The Lighthouse Beaches (Figure 11) are much wider with established multiple vegetated dune ridges on the backshore. Relic coastal dune ridges, separated by swales and ponds dominate the climax forest behind the beaches. The most striking feature of the beaches is the system of large-scale shoreline megacusps spaced at 400-800 m. These. rhythmically spaced features are substantial packets of sand which typically migrate eastward maintaining their identifiable form over periods ranging from months to years. Sediment which is transported along the beach itself occurs within these features. It may be that as little as 20 percent of sediment transported along the Lighthouse Beaches occurs as beach transport; the bulk of sediment transport takes place offshore. As megacusps move eastward so do the rip channel embayments between them. Beach erosion is tied to these rip-channel embayments and consequently it is these pockets of erosion that have been targets of beach nourishment. It has been established that little net erosion or deposition of the lighthouse shoreline occurs through time (Nummedal, 1979).
The nearshore zone morphology of the Lighthouse Beaches is the most complex of the three segments. It includes up to four longshore bars parallel to the beach which are superimposed on transverse bar components and an arcuate bar system (Figure 7). The significantly gentler slope of this multi-barred nearshore zone is a direct consequence of the high rate of sediment supply to this area. The large sediment load for the nearshore zone is largely derived from sources updrift (west of the lighthouse along the erosional neck) rather than the local beaches.
Sediment exchange between the beach and offshore bars is limited to the arcuate bar system and megacusps. Sediment moves eastward along the arcuate bar system with some sediment reentering the beach where the bars attach to the horns of the megacusps. The rest of the sediment continues along the bar system. Sediment is transferred back to the bar system from the beach by rip currents flowing within bar-rip channels emerging from the embayments between megacusps. The entire megacusp system is strongly skewed to the east because of eastward directed incident waves.
Many questions about the spatial and temporal nature of the shore parallel and transverse bar components remain to be answered. For example, the rates, patterns and mechanisms for sediment dispersal in the deeper portion of the nearshore zone are not understood. It is difficult to assess how the detached breakwaters will effect the dynamics of this area.
Things To Look-For:
* Notice the wave height, wave approach direction and shoreline orientation.
* Notice the longshore current direction and speed.
* Observe the texture of sediments at different locations on the beach and backshore.
* The characteristics and spacing of megacusps and inner bars that may be recognized by observing waves breaking over their crests.
* Notice the distribution of pockets of erosion and deposition along the beach and their relationship to beach morphology.
* Notice the vegetated dune ridges and incipient dunes formed by the interaction of vegetation and aeolian activity in the backshore.
*Notice beach ridges and climax forest across the road.

Sunset Point area, beach and lake visible to left.

STOP 3. Beach 10 And East: Gull Point
This stop on the Gull Point segment of Presque Isle (Figure 11) features the beaches east of the prototype breakwaters built at beach 10 in 1978. Depending on the time available we will walk eastward onto Gull Point to see the extensive sand plain and series of accretionary dune ridges.
By this stage in your observations, it must be clear to you that Presque Isle is an eastward migrating spit system that feeds upon itself as it migrates. Within this system, sediment is eroded from the neck, transported across the broad shallow multi-barred nearshore zone of the Lighthouse Beaches and is finally deposited adding to Gull Point, the only net depositional feature along the peninsula. The rapid growth of Gull Point is evidenced by the formation of a series of beach ridges superimposed on recurved spits which wrap around the end of the spit enclosing ponds.
The rapid accretion of Gull Point began in the 1930's possibly in response to the sudden increase in available sand supply from the breached neck in 1917-23, and is continuing today in response to the annual nourishment program. According to the U.S. Army Corps of Engineers (1979) the present volumetric migration rate of 289,100 cubic yards per year reflects the replenishment input which has averaged 259,000 cubic yards per year since 1955. The peninsula's continued eastward migration operates at an annual sediment budget deficit. The present deficit results partly from the spit having migrated to the eastern edge of its underlying platform in response to a longterm rise in lake level (post glacial rise of 1 ft. per 300 yr.). Each future increment of eastern migration of Gull Point requires much larger volumes of sand because the platform itself must prograde into deep water before the spit can be superimposed. Also, the present sediment volume being supplied to the Neck from streams and bluff recession updrift has been estimated at only 30,000 cubic yards per year.(Nummedal, 1984).
The Gull Point beaches receive the lowest annual wave power along the entire outer shore of the peninsula. The orientation of the shoreline is such that only storms with incident waves from the northeast can generate sufficient energy for offshore transport and shoreface broadening. Such storms are infrequent and moderate in strength. This wave climate is such that sediment is kept close to shore maintaining a steep prograding profile.
Because the nearshore slope is steep and the surf zone is narrow only one, or at most two, longshore bars are present close to shore. Because the strongly eastward directed incident waves, rip channels and transverse bar components are strongly skewed to become nearly shore-parallel. This offshore profile is maintained by the prevailing onshore transport of sediments.
The beaches are dominated by megacusps with a spacing of 700-800 m. These megacusps are closely associated with inner bars that commonly weld onto the beaches. The welding bars are much like ridge and runnel systems (swash bar complexes) of ocean beaches in form and behavior. Of course we have no tidal effects here so the dynamics are necessarily different. Migration of megacusps produce rapid changes in beach orientation and beach slope along the Gull Point beaches.
Things To Look For:
* Notice the wave height, wave approach direction, shoreline orientation and longshore current direction and speed.
* Observe the changes in sediment texture with respect to changes in beach morphology and distance from the shoreface. Notice also the heavy mineral concentrations.
* Observe the areas of erosion and deposition along the beach including any evidence of bars in the process of welding to the beach.
* Notice the washovers in areas where the primary dune ridge has been eroded away.
* Notice the different stages of dune ridge formation including the succession of vegetation types that accompanies dune ridge growth.

Thompson Circle loop road on right.

Road to Coast Guard Station on left.

Entrance to Beach No. 11 on left.

Misery Bay on left.
Admiral Perry's fleet returned here after the battle of Lake Erie to spend the winter. The Perry Monument is visible on the point across the bay. Niagara Pond is on the right.

Lawrence Boat Launch on left.

South end of Sidewalk Trail on right.

Entrance to East Boat Livery (Park franchised boat rental area)

Grave Yard Pond on right.

Cross Misery Bay Bridge.

Parking area for Perry Monument on left.

Bike trail crosses road.
Stone rip-rap along bay shore on left. View to left across Erie Harbor to city of Erie.

Entrance to East Pier area parking on left

Dredged harbor area on left is location of the park Marina.
This area supplied much of the initial beach nourishment material in the 1950's. Range lights on left and right are navigational aids for marking the marina entrance.

Bridge over inlet to Long Pond.

This is an area of frequent winter washovers and dune migrate across road.

Pettinato Beach entrance on right.

Waterworks lagoons on right, picnic area on left.

Beach No. 6 entrance on right.

Modern restrooms on right (Barra Beach access).

Beach No. 1 entrance on right.

SatG: A FEW OF OUR FAVORITE PLACES; AN ENVIRONMENTAL AND GEOLOGICAL EXCURSION IN CHAUTAUQUA COUNTY
Richard A Gilman and Jack Berkley
State University of New York College at Fredonia
Fredonia, N.Y 14063
This trip will focus on a variety of geological features and processes of particular interest to students, rather than on results of current research on a single topic. General topics include environmentally important sites, geomorphology and glacial geology, and bedrock geology including unusual structural features. The setting for this trip is a portion of the eastern shore of the Lake Erie Basin in southwestern Chautauqua County. Upper Devonian bedrock units (mostly shale and siltstone) are overlain by Wisconsin-age glacial drift, mostly morainal material on the "escarpment" (edge of the Allegheny Plateau), with post-glacial, pre-Lake Erie lake clay dominating in the glacially-scoured lake plain below. Post-glacial erosion has produced deeply incised fluvial valleys, some with rather spectacular gorges. Human economic activities center on agrarian enterprises, with the famous Lake Erie Grape Belt dominating production in the lake valley.
This field trip will take us to (in order of stops) [1] a "pop-up" structure in Canadaway Creek near the SUNY, Fredonia campus, [2] an active and [3] inactive fly ash waste disposal site, [4] Lake Erie State Park (lake erosion, bedrock features, glacial till), [5] a glacial lake Whittlesey beach deposit quarry, [6] a scenic overview from the "escarpment" of the Lake Erie basin (lunch), and [7] a scenic-educational hike into the Chautauqua Gorge to see bedrock and glacial features, including a pre-glacial buried valley. We strongly advise that all participants bring waterproof boots, or for the more adventurous, sneakers. This apparel will be essential particularly on STOP [7] which requires considerable stream wading. Fig. 1 is a map showing locations of all stops.

SatG: A FEW OF OUR FAVORITE PLACES; AN ENVIRONMENTAL AND GEOLOGICAL EXCURSION IN CHAUTAUQUA COUNTY

STOP 1. Pop-Up Structures
Pop-up anticlines were recorded as early as 1886 by G.K. Gilbert in otherwise flat lying Devonian strata of New York and Pennsylvania (Gilbert, 1886, 1888). He attributed these structures to "thermal expansion of surficial rocks following glacial unloading" (Sbar and Sykes, 1973). Since that time others have reported similar structures (Cushing et.al., 1910, Williams, H.R. et al.,1985, and Adams, J., 1982) in which the axis of the pop-up generally strike N-S or NW-SE. Sbar and Sykes (1973) reviewed the evidence favoring a contemporary ENE to E-W maximum compressive stress for much of the Great Lakes region of North America (Fig. 2), and suggested that "the release of a vertical load in the presence of a large horizontal compressive stress of non-glacial origin, however, may be responsible for the formation of the pop-up... "
Pop-up anticlines in northern Chautauqua County generally have a NW-SE to N-S strike (STOP 7) but some have been found that strike E-W (STOP 1). At this exposure notice that the shaley beds and even some siltstone beds are bent at the fold. Does this imply a certain degree of ductile deformation, and if so what was the mechanism of deformation and when did it occur? If the northwest trending structures are the result of the ENE regional compressive stress, how are the E-W trending pop-ups explained? Coates (1964) describes a 7 foot high, NW striking pop-up that developed overnight in a quarry floor in Ontario. Note that the STOP 1 fold is directly overlain by unconsolidated floodplain deposits and the constituent shale bedrock was, no doubt, subjected to fluvial erosion until "recently" (?). Because this fold represents a positive topographic feature it should be highly susceptible to erosion; note that where the fold crosses the present stream bed it has been planed off completely. Thus, if the Canadaway Creek valley is a post-glacial feature, the STOP 1 fold is probably a fairly recent feature (post-glacial), as an older fold (say; Paleozoic age) should have been eroded down to the current erosion level of the bedrock. We will compare the structural properties of this fold to folds of probable glacial origin at STOP 4 (Lake Erie State Park).

STOP 2. Niagara Mohawk Fly Ash, & Bottom Ash Disposal Site
(permission to visit this facility may be obtained from Mr. Jacob (Dav) Guziac, NiMo, 106 Point Dr. North, Dunkirk, NY 14048 716-366-2885)
The Niagara Mohawk site occupies land that formerly included, the Fredonia Airport on Van Buren Road (Fig 3). It primarily receives ash waste from the Dunkirk Steam Generation Plant located near Point Gratiot, Lake Erie, within the city limits of Dunkirk. This plant began electrical generation in 1949 using Pennsylvania bituminous coal as fuel. It generates 600 megawatts of power fired by about 5,000 tons of coal per day. Originally the ash produced at the plant was mostly "bottom ash", the same "clinkers" or coal cinders produced by home, coal-fired furnaces. However, in 1973 new and more efficient electrostatic precipitators ("scrubbers") were constructed in the exhaust chimneys resulting in cleaner air, but creating addition solid wastes in the form of "fly ash". It is this fine grained fly ash that accounts for the majority of wastes currently dumped at the Dunkirk disposal site. An average of about 450 tons of fly ash deposited at the site every working day (Sunday excluded). Some bottom ash is also dumped at the site (avg. 1/90-2/90 was 130 tons), although much of this is bought by the Town of Pomfret for use as road aggregate. The disposal site also receives some wastes from an oil-fired plant in Oswego.
Of obvious environmental concern is the efficiency of safeguards designed to prevent aqueous leachates at the disposal site to contaminate local surface and groundwater supplies. This is controlled for the most part by clay and plastic bottom liners. Leachates are directed toward an artificial pond ("Sed Basin" in Fig. 3) that is frequently monitored for contaminants (see Table 1). Water from this pond is allowed to flow into a nearby creek after testing shows it to be free of significant contamination. Groundwater is also monitored by a series of test wells (Fig. 3) located around the perimeter of the site. Dust abatement is performed by watering trucks that obtain water from a larger artificial pond adjacent to the settling basin (Fig. 3).

STOP 3. Frame Trucking Co. Reclaimed Disposal Site.
We will visit the a nearby "reclaimed" site owned and formerly operated by the Don Frame Trucking Company (Fig. 3). This disposal cell was active from 1971 to 1985.
Metzger (1974) noted that groundwater samples taken near the active fly ash disposal cell at that time (Frame site; STOP 3) showed that efforts to contain groundwater contamination were successful. However, he also showed that water samples collected near an older dump site (near the entrance on Van Buren Road) were contaminated with high concentrations of iron and manganese. It is safe to conclude that these metals were derived by leaching of the old fly ash materials by groundwater, and that other heavy metals (not analyzed) may also have shown higher-than-background abundances. Table 1 shows that containment techniques at the current cell are successful in keeping contamination restricted to the disposal site. All metal values are quite low and abundances for organics are all below detection limits. Hopefully, this situation will be maintained in subsequent years, but this remains to be seen.

STOP 4. Lake Erie State Park
The lake shore here offers us the opportunity to study several features of interest: (1) jointing developed in the South Wales member of the Canadaway Formation... we will also discuss additional studies on jointing in this area and across the Allegheny Plateau, (2) shoreline erosion... recent problems of severe erosion rates associated with high lake levels and how the U.S. Corps of Engineers resolved the problem at the bath-house, (3) a beautiful exposure of glacial till overlying shale bedrock along with lacustrine deposits overlying the till, and (4) septarian concretions.
JOINTS: In recent years joint patterns across the Allegheny Plateau have received considerable attention (Engelder, 1982, 1985; Engelder and Geiser, 1980; Gross, 1989). Fig. 4 shows results of these studies. Of particular interest is the noticeable change in dominant joint orientation from northwest to northeast that takes place in southern New York and northern Pennsylvania (Fig. 4C). There is also a clear need for additional data from western New York. This will in part be addressed by our discussions here at STOP 4. The strong ENE set of extensional joints (Fig. 4B) is interpreted as having formed in a neotectonic stress field with an ENE direction of maximum compressive stress (Engelder, 1982). As summarized by Gross (1989), "These features are thought to form near the earth's surface as the result of uplift and erosion and are controlled by the orientation of the contemporary tectonic stress field."
At Lake Erie State Park the South Wales member of the Canadaway Formation is well exposed at water level. It displays an abundance of joints oriented approximately N 50 W and N 30 E. Fig. 5C is a rose diagram of 134 joints measured at this location.
In preparation for this field trip RAG undertook a reconnaissance study of joint patterns in each member of the Canadaway Formation in northern Chautauqua County. Results are shown rose diagrams in Fig. 5. These diagrams show that in all cases there is at least 1 strong NE joint set (N 25-35 E and/ or N 65-70 E). In addition a N 30-40 W set and/ or a N 50-60 W set is present in some units. However they are not consistently present in all exposures of these members. For example, the Northeast shale in Canadaway Creek has abundant NW joints, but very few are seen in Chautauqua Gorge (Fig. 5I & 5J).
Using the criteria that younger joints abut older ones it appears that N 35 W joints are younger than the N 65 E set and N 70 W joints are older than the N 65 E set. Gross (1989) found that ENE joints in the Lockport dolomite are consistently younger than NW sets.
How does all of these relate to earlier joint studies on the Allegheny Plateau? ... that will be part of our discussion.
SHORELINE EROSION: Wave-induced erosion along the Lake Erie shoreline is a problem that has attracted a great deal of attention in recent years. From a human standpoint shoreline erosion destroys valuable lakeshore property and jeopardizes the structural integrity of buildings and other near-shore constructions. Sand beaches are also affected by increased erosion during high-water times, with sand being carried farther out in the basin during times of increased wave activity. Fig. 6A shows that the year 1986 experienced especially high water levels in Lake Erie. In fact that year set an all time record, exceeding previous highs measured in 1973 (573.51 feet). The highest level recorded in 1986 was 573.70 recorded during the summer. Levels have generally decreased since that time and were especially low during the drought of 1988 (Fig. 6A). In fact, the most recent Army Corp of Engineers lake level report suggests that lake levels will remain well below average during the summer of 1990. During times of high lake levels erosion rates increase because waves are more likely to impinge upon easily erodible glacial sediments that overlie bedrock. During low water periods waves contact bedrock which erodes less efficiently than glacial till. In addition, during low water periods wave energy is likely to be dissipated over a broad area of lake bottom, thus lessening the energy waves can expend on erosion (Metzger, 1974).
Fig. 6B shows the typical lake level pattern over any given year which is to rise during the spring and summer months and decrease during winter and fall. This is, perhaps, fortunate because winter storms can be particularly energetic. Storms at any time of the year cause strong prevailing winds to develop on the lake basin. This results in "setups", a process where water literally piles up on one side of the lake, usually the eastern or southern side. Storm setups combined with unusually high water levels can cause considerable erosion along the lake shore, and may destroy beaches. Sand carried out to deeper levels usually returns, however, as lake levels return to more normal values (Metzger, 1974). Fig. 7 shows that the Lake Erie shoreline in western New York is generally subject to light to moderate erosion.
A dramatic example of severe shoreline erosion directly affecting human activities can be observed at Lake Erie State Park. Erosion of virtually unconsolidated glacial till underlying the bathhouse was threatening to undercut this building's foundation. In 1986 the U.S. Army Corp of Engineers proposed an erosion abatement plan to save the building from probable structural damage resulting from this erosional undercutting. The bathhouse, situated on a 25 foot high bluff, was valued at about $300,000 by the state in 1986, so cost considerations dictated that constructing a new facility would be more expensive than saving the old building. The Corp of Engineers, therefore, devised a plan to construct a "rubble-mound" revetment that would extend 250 feet along the toe of the bluff, and extend up the bluff to the bathhouse. The revetment project was subsequently approved for construction. It consists of a gravel fill layer overlain by large limestone boulders. A plastic filter fabric was laid down under this material to keep bluff materials from infiltrating the revetment, and a series of buried plastic pipes aids drainage. The estimated cost of the project prior to construction was $200,000. Fig. 8 shows a map view of the construction plan that was eventually completed in 1988.
GLACIAL DEPOSITS: Bedrock along the beach area is overlain by unconsolidated surficial deposits of glacial origin, deposited during the Wisconsin glacial advance. This material is well-exposed on the cliff face along the beach and consists of buff-colored, unstratified, badly sorted till, overlain in some areas by finely laminated, gray lake clay. The till consists of some recognizable local bedrock material especially in the lower horizons, but also includes pebbles through boulder-size rocks mostly of metamorphic or igneous origin. Some large blocks of relatively coherent bedrock were incorporated into the lower till layers in some areas. These blocks display local folding that may have been induced by glacial movement. We will visit one particularly well-exposed site and compare this folding to that observed in the pop-up structures observed at STOP 1.
Lake clay is exposed in some areas above the till, but has been removed by erosion elsewhere. It is thinly laminated, nearly pure gray clay in many areas but locally is mixed with sand, gravel or pebbles. The layering may represent a response to seasonal depositional conditions (varves), although this is subject to debate. Most varved clays show distinct color differences, apparently absent here. This clay was deposited by one of the precursor lakes to the present Lake Erie, Whittlesey or Warren. Judging from the low stratigraphic position of this clay relative to the till layer, the lake clay was probably deposited be the earlier lake, i.e. Whittlesey.
SEPTARIAN CONCRETIONS: A few hundred feet west of the till exposure, numerous 3 to 5 feet diameter septarian concretions are exposed at water level. According to Pettijohn (1975) the formation of septarian nodules appears to involve development of a nodular body, case hardening of the exterior with dehydration of the interior and generation of the shrinkage-crack pattern, and partial or complete filling of the cracks with precipitated mineral material, thereby producing the vein network of the nodule. Shrinkage and production of cracks imply a gel-like character of the original body.
Ultimately, development of concretions may be related to bacterial fermentation or organic matter during shallow burial. Such reactions apparently generate water, carbon dioxide and biogenic methane. This leads to an increase in the pH of the pore fluids allowing for carbonate precipitation. The carbonate cements which may include calcite and siderite, commonly develop as concretions that may be found intermittently along beds. Some of the nodules, the septarian concretions, have undergone dehydration with accompanying development of shrinkage cracks (Selley, 1988). These cracks are later filled in by precipitation of carbonate minerals (calcite and siderite) from infiltrating hydrous solutions. In addition, the relatively uncommon mineral, barite (BaSO4), is a common accessory mineral in many septarian concretions.

Route 20 lies along the top of the Lake Warren beach ridge
This will be discussed at the next stop.

View of Lake Whittlesey beach terrace at 10 o'clock.

STOP 5. Gravel Pit In Lake Whittlesey Beach Deposits
As the Wisconsin ice front retreated north of the high ground of the Portage Escarpment, meltwater that had previously drained southward was now trapped between the ice margin and the escarpment. This led to numerous small lakes and eventually to the development of three large lakes (the ancestral Great Lakes), Lakes Maumee, Whittlesey, and Warren. Two of these, Whittlesey and Warren, formed beach terraces that are well preserved in Chautauqua County (Fig. 9). Prior to the deglaciation of the Mohawk and St. Lawrence river systems the drainage of both lakes Whittlesey and Warren was westerly. As the northeast outlet channels became ice free Lake Erie was established at its present level. The sequence of deglaciation events for Chautauqua County is shown in Fig. 10.
In the Westfield-Fredonia area, Route 20 lies along the Lake Warren beach and Webster Road along the Lake Whittlesey beach.
STOP 5 is in a Lake Whittlesey beach deposit where the following features should be noted; the style and dip of bedding, composition of the pebbles in the gravels, and the structures and textures within the beds.
Due to post glacial isostatic rebound the elevations of these beach terraces rise fifty feet toward the east between the villages of Ripley and Silver Creek, a distance of about 40 miles.

At about this point we leave the lake plain and proceed up the escarpment.

STOP 6. Thayer Road Overlook
The Lake Erie Basin was likely a low area rimmed on the south by a cuestaform ridge in pre-glacial times_ (Dreimanis, 1969; Gravenor, 1975). The sharp rise in topography in front of this overlook is called the Portage Escarpment that although modified by glacial activity is believed to have formed by subaerial erosion prior to Pleistocene glaciation. Bedrock of the escarpment consists of the Canadaway Formation (Fig. 11). Unlike the Niagara Escarpment to the east, the Portage Escarpment is not capped by the resistant strata but is dominated by shales with interbedded thin siltstones. Muller and Fahnestock (1974) asked, "If the topography be truly cuestaform, where are the resistant capping strata responsible for the scarp which is 700 to 1100 feet high in eastern Chautauqua County?"
The overlook is situated on top of the Lake Escarpment Moraine, a moraine complex that Muller (1963) correlates with the Valley Heads Moraine in the Finger Lakes region. This is the result of a stationary ice front at about 14,000 B.P. The moraine is a prominent feature from Northeast, PA to east of Gowanda, NY.

Route 20 follows along the Lake Warren beach as we proceed toward Westfield.

Bridge over Chautauqua Creek.

STOP 7. Chautauqua Gorge Hike
Park at the end of the road, across from gas well.
Note: The hike will take about 3 hours and much of the time we will be walking in the stream. Consequently you should have footwear that you don't mind getting wet and that has good traction. These rocks are extremely slippery when wet...USE CAUTION.
As the ice margin retreated northward from the Portage Escarpment, north draining streams such as Chautauqua Creek were established. Some of these streams carved deep gorges across the escarpment, in most cases carving their channels into the Devonian bedrock, but in other instances exhuming parts of pre-glacial (or interglacial) valley systems (Muller, 1963). These streams head less than 10 miles south of the Lake Erie shore. Farther south streams drain southward into the Allegheny River.
Stratigraphic units we will see on our hike are the Dexterville (siltstone), exposed where we first enter the creek; the overlying Ellicott, seen high on the steep valley walls; and as we walk downstream we will cross into the Northeast (shale) that lies beneath the Dexterville (Figs. 11 & 12).
We will walk approximately one mile downstream examining the following features: The stratigraphic influence on joint development, pop-up structures, fossils from the Ellicott, cone-in-cone concretions, and a pre-glacial channel filled with kame gravels. We will also consider the sedimentology of this interval of the Canadaway Formation.
JOINTING: Systematic joints are absent in the Dexterville member but abundant in the Northeast shale. A rose diagram of 70 joints is shown in Fig. 5J. Most are approximately N 45 E.
POP-UP STRUCTURE: One well developed pop-up will be examined. It strikes N 27 W parallel to a localized northwest joint set. Dips at the crest of the structure are 15 SW and 6 NE. The structure is about 20 feet across and has an amplitude of about 2 feet. This example is quite different from the anticline seen at Stop 1 in that there is no bending at the hinge.
CONE-IN CONE CONCRETIONS: Cone-in Cone concretions are known from several locations in western New York and Pennsylvania from the Northeast shale member of the Canadaway Formation. A study by Gilman and Metzger (1967) found that:
"The cone-in-cone concretions examined in this study occur as two hemispheres of cones separated by a layer of bedded siltstone. Microscopic examination reveals both a bladed and radial extinction pattern in the equigranular calcite constituting the concretion. The cones are disrupted by two systems of fractures: those termed major form the boundary or the cones, those termed minor penetrate the cones and are associated with the formation of clay rings which encircle the cones.
X-ray analysis shows all of the CaCO3 in the concretions to be calcite. The predominate clay minerals are illite and chlorite. The concentration of mixed layer clay is greater within the concretions than in the adjacent sediments.
The cone-in-cones are thought to have originated from a syngenetic concretion of fibrous aragonite. The conical structures are believed to have formed while the surrounding clay materials were still plastic, and that clay was introduced along the major fractures as the cone-in-cone structure developed."
A cross section of a typical concretion is shown in Fig. 13.
PALEONTOLOGY AND SEDIMENTOLOGY: Faunal communities of the Dexterville and Ellicott members were studied by Burrier (1977). His table of fauna from various lithologies within the Chadakoin Formation is shown in Table 2. He concluded that these strata represent regressive and transgressive facies of delta front and prodelta environments. Miller and Lash (1984) consider the Northeast shale to be a thickening-, thinning - upwards sequence of turbidites deposited from unconfined sheet-like turbulent flows, perhaps originating from storm activity on the shelf to the east.
PRE-GLACIAL VALLEY. The topographic map (Fig. 14) of the part of Chautauqua Creek known as THE GULF shows a pronounced change in valley shape: a narrow steep walled bedrock gorge in the region where we will start our hike, to a wide flat floored valley about a mile downstream. The north end of this wide valley segment is again constrained between narrow bedrock walls. Post glacial erosion by Chautauqua Creek has carved a channel that in part cuts across a pre-glacial valley that was subsequently filled with glacial deposits. Muller (1963) interprets these as kame deposits. The extent an orientation of the older channel is not certain.

SunA: SUBMARINE EROSION AND CONDENSATION IN A FORELAND BASIN: EXAMPLES FROM THE DEVONIAN OF ERIE COUNTY, NEW YORK.
CARLTON E. BRETT
GORDON C. BAIRD
SUNY College at Fredonia
Geologists have long recognized the importance of unconformities in the stratigraphic record. Sloss (1963), for example, used six widespread unconformities to subdivide the North American stratigraphic succession into five major sequences or megasequences. This seminal work was, in some ways, the forerunner of sequence stratigraphic analysis which has recently resulted in a revitalization of stratigraphy (see articles by Vail and Mitchum, 1977; Vail et al., 1977; Posamentier et al., 1988; Van Wagoner et al., 1988; Baum and Vail, 1988; see Fig. 1). It is generally accepted that the stratigraphic record is highly incomplete and that much time is represented at some bed contacts. However, it is not always clear where these surfaces exist within stratigraphic sections. Many erosion surfaces, particularly in marine mudstone successions, are very subtle and can only be recognized with detailed observations. Nonetheless, many such surfaces are traceable over vast areas, forming the basis for a new dynamic view of stratigraphic processes within epicontinental sea and foreland basin settings.

SunA: SUBMARINE EROSION AND CONDENSATION IN A FORELAND BASIN: EXAMPLES FROM THE DEVONIAN OF ERIE COUNTY, NEW YORK.

STOP 1. Type Section Of Dunkirk Shale Member, Point Gratiot At Dunkirk.
Turn right onto Cedar Beach Parking area. Niagara Mohawk coal-powered generating station straight ahead (to NE). Proceed north on foot for approximately 500 feet along beach to northeastfacing lake shore outcrop near lighthouse museum at Point Gratiot.
This outcrop is excellent for viewing the sharp contrast between the grey-green bioturbated, but non-shelly, mudstone of the Hanover Shale Member and the black, organic-rich, laminated facies of the overlying Dunkirk Member. A conformable, bioturbated contact between Hanover and Dunkirk can be seen below the 15 to 18 cm thick (6 to 7 inches) basal Dunkirk black bed which dips southward below the water at this section. However, a sharp, erosional discontinuity with associated reworked debris marks the contact between the 12-13 cm (5 inch) thick grey-green bioturbated bed above the 18 cm (7 inch) basal bed and the over lying continuous black shale succession .
Close examination of this contact shows that abundant reworked (detrital) pyrite is present along it with lesser amounts of carbonized wood, conodonts, fish bones, and pyritic goniatite steinkerns (Baird and Brett, 1986a); much of this material is probably derived from the 12-13 cm (5 inches), grey-green mudstone unit which is conspicuously rich in pyrite cemented and overgrown burrow tubes, although the abundance of wood suggests that the basal few inches of the overlying black shale is unusually condensed, recording the descent of numerous logs from the water surface over a long period of time. This lag unit also records bioturbation, which at this section, was sufficient to flux the broken pyritic tubes into random orientations.
As this discontinuity is traced northeastward to the vicinity of Java Village, Wyoming County, more and more beds progressively appear beneath it such that this break passes essentially to extinction (see Fig. 5; Baird and Lash; FIELD TRIP SAT. A, this volume). Instead several black shale beds alternating with bioturbated and non-bioturbated grey-green mudstone make up an intervening sequence several meters-thick. Most of the thin black shales, however, display minor diastemic basal contacts with the grey-green beds marked by minor detrital pyrite. Collectively, these diastems downcut underlying units as they are traced southwestward such that higher discontinuities downcut, through lower ones until only a single 5 inch (12-13 cm) grey-green bed remains at this locality. This illustrates the pervasiveness of submarine erosion associated with the transgressive grey- to-black facies change beneath even very thin black shale units. It also illustrates the distinctive character of condensed sedimentary deposits involving alternations between dysoxic and anoxic facies. For additional information about this outcrop, see Baird and Lash; FIELD TRIP LOG SAT A: STOP 2 (this volume).

Dunkirk Harbor Complex visible (to left) for next mile.

Cross Walnut Creek.
Hanover-Dunkirk contact is at base of bridge. Stebbins Road bridge (being repaired to right) collapsed in 1987, killing one person, when an overweight vehicle caused the bridge to plunge.

Cross Silver Creek, Dunkirk Shale at base of bridge.

Dunkirk Shale above Hanover Shale in Thruway cut
Dunkirk Shale above Hanover Shale in Thruway cut immediately beyond (downhill from) the Silver Creek exit.

Cross Cattaraugus Creek floodplain.
Sand and gravel pits have been opened on this bottom in the vicinity of the Thruway.

Cross Cattaraugus Creek. Begin to cross Seneca Indian Reservation.

Cross Big Sister Creek.
Angola Shale Member of West Falls Formation exposed below bridge.

Cross Eighteenmile Creek.

STOP 2. Middle And Upper Devonian Marine Deposits Along Eighteenmile Creek.
Turn right onto first side street north of Route 5 bridge. Park vehicles and proceed down path at end of street to large cutbank section on north side of Eighteenmile Creek 200 ft. east of (upstream from) Route 5 bridge.
This large outcrop shows to maximum advantage the Tichenor Limestone, the overlying Windom Shale Member, and the major discontinuity at the top of the Windom (marked by North Evans bone-conodont-rich debris) which marks the base of the Upper Devonian series in this area (Figs. 3, 4A). We will see the North Evans to better advantage at the next stop (see STOP 3) and will, thus, focus on the Tichenor and basal Windom shale at this stop.
The Tichenor is a 0.7 m (2 ft.)-thick, widespread crinoid-brachiopod grainstone-packstone unit which is also notable for large corals (Heliophyllum, Eridophyllum, Favosites), large bivalves (Plethomytilus, Actinopteria) and large fragments of the trilobite Phacops. As is obvious from the texture, this is a medium to high energy deposit which may have accumulated within the depth-range of fair-weather wave-base. It is also extremely condensed and time-rich; in the western Finger Lakes region, deposits equivalent to the western Tichenor (mostly Deep Run Shale Member) reach a thickness of almost thirty five meters. Through a combined affect of westward stratigraphic thinning and westward lateral facies change from mudstone to shelly carbonate, the Deep Run is replaced by very thin clean skeletal carbonate in Erie County. The base and top of the Tichenor at this locality are sharp, reflecting erosional processes. The base marks a major disconformity separating deposits of the Ludlowville Formation from the overlying Moscow Formation; the Jaycox Shale Member of the Ludlowville Formation is progressively bevelled below this contact from the Genesee Valley westward such that only the base of the Jaycox is visible at Buffalo Creek in eastern Erie County and none is visible west of the north branch of Smoke Creek in south Buffalo. This bevelling was produced by a major regression event which caused synchronous submarine (and possibly subaerial) erosion in central and eastern New York State (see McCave, 1973; Baird, 1979; Baird and Brett, 1981) and this contact may be a bona fide sequence boundary. Examine overturned Tichenor blocks for large, abrasion-enlarged, hypichnial trace fossil markings produced by large arthropods; these resting- (or dwelling) excavations into firm Wanakah marine muds were later filled-and casted by the Tichenor skeletal sands.
The top of the Tichenor is also marked by a submarine discontinuity, perhaps of similar hiatal magnitude. Submarine erosion that preceded deposition of the Windom, removed most of (or all of) three units (Deep Run-equivalent carbonate beds, Menteth Member, Kashong Member) which overlie the Tichenor east of Buffalo. This erosion produced a submarine hardground at this locality and at other western Erie County Tichenor sections). Examine this surface closely for auloporid corals and crinoid holdfasts which encrust this contact and for the presence of phosphatic nodules and steinkerns reworked from below (see Brett, 1974; Brett and Baird, 1974 for additional description of this surface).
The overlying Windom Member records transgressive deepening to quiet, open-shelf conditions minimally affected by storm wave reach. Fifty centimeters (16 in.) above the base in a unit (Bayview Coral Bed) which is rich in large brachiopods, particularly Spinatrypa, and which locally yields large rugose corals, including Cystiphylloides and Heliophyllum along this bank. Above it is a calcareous mudstone unit (Smoke Creek Bed) which is well known for complete enrolled and outstretched specimens of the trilobite Phacops rana (see Brett and Baird, 1982 for additional information on this unit).

Cross Weyer Creek.
Fossiliferous Middle Devonian Wanakah Shale exposed mainly downstream (north) of Route 5 bridge.

Cross Amsdell Road
Amsdell Creek, further up Amsdell Road, has been an important source for conodonts and fish fossils from the North Evan bone-conodont bed.

STOP 3. North Evans Bone Bed And Genundewa Limestone
Park on shoulder pull-off just south of the railroad tracks . Proceed on foot 0 .3 mile southwest along a path border ing tracks to the abandoned Lehigh Cement Co. Shale quarry which is southeast of the tracks.
This abandoned shale pit, developed by the Lehigh Cement Co. as a source of claystone for the mill (now defunct) in Lackawanna, contains a stratigraphic succession from the Middle Devonian in the Upper Devonian. The Quarry walls about 16 m (50 ft) high expose the Upper Devonian Middlesex-Cashaqua Shale. The quarry is floored mainly by the shaley upper contact of the Genundewa limestone and the West River Shale. In a narrow pit the Genundewa is breached and a section extends down some 2.5-3 m (8-10 ft.) to, or just below, the Amsdell (Praeumbona) bed of the Windom shale. The Windom here is in contact with the North Evans Limestone and the contact is an erosion surface showing a characteristic "rip-up" horizon. We will focus on lag deposits (North Evans Bone-Conodont Bed) associated with an erosional contact between the grey Windom Member (Givetian) and the overlying Genundewa Limestone of Late Devonian (early Frasnian) age. For additional information on these units, see: Sass, 1951; Huddle, 1981; Brett, 1974; Brett and Baird, 1982; Baird and Brett, 1986a.
The North Evans Limestone, or "Conodont bed" of older literature, is typically a 0.5 to 6 inch- thick packstone- grainstone unit composed of reworked crinoid ossicles, conodonts (including many mixed from older zones) fish teeth and armor fragments, as well as calcitic brachiopod, coral, and trilobite fossils derived from the underlying Windom or from intervening beds now removed. Conspicuous within the North Evans at this locality and also at the abandoned Penn Dixie Shale Pit at Bayview, New York (see Brett and Baird, 1982: STOP 2) are reworked limestone concretions from the underlying Windom. These are often stacked like shingles and they typically have a green exterior patina of glauconite as well as surface dissolution pits produced following exhumation on the seafloor.
The overlying Genundewa Limestone is composed almost entirely of Styliolina fissurella, a problematic millimeter-long conoidal calcitic shell which may be of tentaculitid affinities or the shell of an unknown protistan organism (Yochelson and Lindemann, 1986). Wood debris, goniatitid and orthocerid cephalopods, and the bivalves Buchiola and Pterochaenia comprise the remainder of a low diversity biota. The Genundewa appears to be a classic example of the pelagic Cephalopodenkalk facies of the European and North African literature (Tucker, 1973). As such, it records very slow sedimentation in an offshore, sediment-starved, dysoxic environment.
Although the North Evans rests on fossiliferous Middle Devonian deposits at this locality and would appear to record a simple transgression over the oxic, shell-rich Windom facies, a more complex story emerges when the same bed is viewed in eastern Erie County (see STOP 7); at that section, the North Evans overlies brown-black anoxic facies of the Upper Devonian Penn Yan Shale Member. Hence, an apparent regression with attendant seafloor erosion is recorded after deposition of the Penn Yan and prior to final accumulation of the North Evans lag. The North Evans-Genundewa succession is, thus, a transgressive interval culminating in the deposition of brown-black anoxic deposits of the overlying West River Shale Member which is visible here above the Genundewa Limestone. The North Evans and Genundewa beds probably correspond, respectively, to the transgressive surface and overlying condensed interval in the sequence stratigraphy model (see text); they probably correspond, in part, to other sediment-starved condensed units, such as pebbly greensands and bone beds identified by sequence workers in younger sedimentary systems (see Loutit et al. 1988; Baum and Vail, 1988).
The North Evans lag deposit was apparently reworked into the dysoxic Genundewa outer shelf-slope setting because the encrinitic-bone-conodont hash layer grades upward into Genundewa facies and it underlies the Genundewa throughout Erie County except for exposures along Lake Erie near Highland-On-The-Lake where a brown-black shale subfacies of Genundewa overlies the North Evans (Brett and Baird, 1982). Hence the North Evans is rich in carbonate debris with only minor amounts of detrital pyrite; compare the North Evans with the pyrite-dominated lag that we saw at STOP 1 and, particularly, what we will see in the Leicester Pyrite deposit at STOP 8. Exhumed Windom calcareous shell material was apparently dissolved in the largely anoxic Geneseo basin setting to produce the residual detrital pyrite lag deposit of the Leicester (Baird and Brett, 1986a). Conversely, detrital pyrite was differentially stable in this anoxic or minimally dysoxic setting. Carbonate undersaturation and/or low pH conditions of the basal Geneseo substrate environment are clearly not evident for the North Evans-Genundewa setting to anywhere the same degree. Only where a black shale subfacies of Genundewa directly overlies North Evans along the Lake Erie shore, does the North Evans lag deposit begin to become rich in detrital pyrite, poor in carbonate debris, and laterally discontinuous (lenticular) in outcrop, the way the Leicester always appears.
Fossils to look for in the North Evans are crushing teeth (tritors) of ptyctodonts, an extinct fish order, placoderm dermal armor and jaw fragments, tricuspate cladodid shark teeth, as well as reworked Windom calcareous fossils, including the trilobite Phacops rana.

Cross Morse Creek.
One of many shore area localities in the richly - fossiliferous Middle Devonian Wanakah Shale Member.

Excellent view of Lake Erie, Buffalo-Lackawanna skyline for next 0.6 mile.

Mudstone (probably Wanakah) exposed along Thruway entrance ramp.

Cross Smoke Creek
Ledyard Shale Member exposed to right (upstream) from Thruway.

Cross Cazenovia Creek.
Middle Devonian black Levanna Shale Member exposed upstream (to right) from Thruway bridge.

STOP 4. Submarine Discontinuity Within Middle Devonian Levanna Shale
Pull off from Union Road to the right onto a dirt road and small parking area in vacant lot immediately before bridge over Buffalo Creek and immediately after passing junction of Indian Church Road on the left. Proceed north, on foot to creek. Cross creek if water is not high.
Along this cutbank exposure one can observe two key lithologic divisions of the Middle Devonian Levanna Shale Member of the Skaneateles Formation which are currently unnamed. Just above water level is a calcareous, dark grey-shale division which yields the diminutive brachiopod Ambocoelia and specimens (often complete) of the trilobite Phacops rana. A submarine discontinuity (prominent undulatory outcrop reentrant) separates this lower unit from a fissile, black shale upper division, rich in the brachiopod Leiorhynchus and the aforementioned problematic small conical fossil Styliolina. This boundary is traceable as far east as Oatka Greek near Pavilion in Genesee County. The units in this section record oxygen-deficient outer shelf-to-basin conditions with the lower division recording dysoxic to minimally oxic conditions and the upper division recording lower dysoxic to near-anoxic conditions ("exaerobic" zone of Savrda and Bottjer, 1987) along the seabed.
This discontinuity is distinctive for its distinctly undulatory appearance; troughs between 0.5 and 2.0 meters (1.5-6.5 ft.) in width and between 12 and 45 cm (5 to 16 in) in depth alternate with inter-trough ridges and platforms (Fig. 5A). The troughs are erosional runnels cut into division 1 deposits which are aligned in a nearly north-south direction transverse to the creek channel (Fig. 5B). Some runnels bifurcate but most remain simple and linear. Trough bottom deposits often include calcareous brachiopods, Phacops, and Styliolina debris admixed with fish teeth and dermal plates. These lags are often at channel bottoms but they can occur in axial channel sediments above channel bottoms. Some troughs appear to have been repeatedly filled with sediment and scoured out by currents; these troughs display nested erosional scour surfaces with the sharpness of scour contacts varying from clear to diffuse (Fig. 8C). Evidently some episodes of scour removed only water-rich surface mud while others cut into firm muds.
Clearly, this section records a type of sedimentary condensation where repeated sediment accumulation and scour were dominant sedimentary processes. The overall upward change from division 1 to division 2 appears to be transgressive with the consequent development of an erosional surface; the complex channel-fills appear to correspond to the interval of maximum sediment-starvation and sedimentary condensation which overlies the transgressive erosion surface.
These erosional runnels are probably submarine furrows (sensu Flood, 1983), which are rarely reported from the stratigraphic record. Furrows are believed to form through the action of abrasive horizontal, debris-laden current vortices which scour the bottom into linear runnels within a sustained unidirectional current regime (Flood, l983). The complex "cut-and-fill" histories of the Levanna runnels is a testament to the unidirectional character of the currents which produced them. We are currently studying these features at this locality to establish which way the currents flowed and are also examining all other similar discontinuities to determine if similar runnels are distributed along them.

Cross Cayuga Creek.
Middle Devonian Onondaga Limestone is exposed below bridge and upstream (to east).

Cross Cayuga Creek.

STOP 5. Volcanic Ash Layers In Upper Onondaga Limestone Along Cayuga Creek.
Exposure of Onondaga Limestone along Cayuga Creek (to right). Park on asphalt driveway next to first house on the right. Proceed carefully down slope to south side of creek.
This cutbank exposes two thin metabentonite layers within the upper part of the Onondaga Limestone Formation (Middle Devonian: Eifelian) which comprise part of the "Tioga Ash" (metabentonite) complex of beds discussed in Devonian literature (see Dennison and Textoris, 1978; Conkin and Conkin, 1984; Rickard, 1984; Sparling, 1988). Dennison and Textoris (1978) and Dennison (1983) believe that the tuff originated in what is now northern Virginia and that Devonian prevailing winds carried the winds predominantly westward (in the present sense) into the U.S. midwestern region.
The Cayuga Creek section exposes two metabentonite (K-rich mixed-layer; illite-smectite) beds which are about 16 inches apart with the lower one just below the water level. The higher metabentonite is probably the Onondaga Indian Nation ("O.I.N.") metabentonite of Conkin and Conkin (1984) which corresponds to the "Tioga B" metabentonite of Rickard (1984). The lower metabentonite is probably the Cheektowaga (No .2) metabentonite of Conkin and Conkin (1984); both of these ashes are exposed in the nearby Federal Crushed Stone Corp. Quarry (see Conkin and Conkin, 1984). Although most workers place the boundary between the Moorehouse Member and the overlying Seneca Member of the Onondaga at the horizon of the O.I.N. (Tioga B) ash (see Rickard, 1975, 1984), Conkin and Conkin (1984) place it about 0.5 m higher at the position of a bone bed which is visible in the quarry and which may be present in this section. Uncertainty exists with surface correlations because outcrops in the upper Onondaga-through Marcellus interval are nearly absent in western Genesee and Erie counties. In any case, this section and one in the nearby Federal Crushed Stone Corp. Quarry west of this stop, are the only outcrops showing any part of the Tioga complex of ashes in this region.
The upper metabentonite is a brown mudstone layer with a bronze-yellow micaceous luster which shows some evidence of bioturbation. The lower, less ash-rich unit, contains abundant fossils including rugose corals, bryozoans, pelmatozoan debris, and the trilobite Phacops. The corals, interestingly, are highly abraded and fragmental; this suggests that the lower "ash" might not be the record of a single "mega-eruption" or closely-spaced series of "eruptions" but is rather a condensed unit within Onondaga where pyroclastic debris and other terrigenous sediment became concentrated over a long period of time relative to carbonate. The occurrence of the uppermost Tioga unit ("Restricted Tioga" division of Conkin and Conkin, 1984; "Tioga A" Bed of Rickard, 1984) above the basal-Marcellus transgressive bone bed lag on uppermost Onondaga deposits, suggests a similar story of selective pyroclastic-enrichment associated with sediment-starved bottom conditions (Baird and Brett, 1986a, b).
This brief stop simply illustrates another unusual type of sediment associated with apparent sediment starvation. What is needed is detailed study of sedimentary structures and sedimentary petrography associated with the Tioga deposits to obtain answers concerning sedimentation rates and paleoenvironmental conditions associated with the formation of these enigmatic event-beds.

Cross Cayuga Creek

Cross Cayuga Creek.
Middle Devonian black and dark grey shales of the Oatka Creek Member are intermittently exposed along creek in this area.

STOP 6. "Precursor Bed" At Base Of Middle Dev Stafford Limestone Member
Turn right off of Pardee Avenue into a parking area at Como Park. Proceed on foot about 400 feet west to Lake Road bridge downstream from small dam on Cayuga Creek. .
Along the banks and bed of Cayuga Creek between the dam and base of the small waterfalls lip at the Lake Avenue bridge are exposures of the Stafford Limestone Member, the basal division of the Skaneateles Formation. Downstream from the water falls are intermittent exposures of the black, fissile, organic-rich Oatka Creek Member of the underlying Marcellus Formation which is mostly covered. Near the falls and bridge, the topmost few feet of the Oatka Creek Shale can be examined on the south side of the creek; these uppermost Marcellus beds are dark grey-brown in color and they yield a meager dysoxic biota consisting of the rhynchonellid brachiopod Leiorhynchus, Styliolina, and numerous flattened composite molds of an orthoconic nautiloid.
The Stafford, in Erie County, is a three-part member consisting of a basal, thin, shell-rich muddy limestone bed (Stafford "A" bed), a middle, shaley interval several feet thick which contains nodular micritic concretionary beds, and an upper cherty limestone division, termed the Stafford "B" bed, which is 0.6 - 1.3 m (2 to 4 feet) in thickness and fossiliferous (see Meyer, 1985). In central New York, the equivalent Mottville Member has a shell -rich "A" bed division, succeed by a variably thick middle "shale" division followed by a micritic or siltstone regressive capping unit which corresponds to the Erie County, chert-rich ("B") micritic division visible by the Como Park dam (Grasso, 1986; Meyer, 1985). Despite significant thickness variations of the "middle shale" and "B" bed divisions along the Stafford-Mottville outcrop strike between Buffalo and the Chenango Valley, the "A" bed remains relatively thin, usually between 8 and 30 cm (0.2 and 1.0) foot in thickness, and it is typically a densely fossiliferous calcareous mudstone, both overlain and underlain by sparsely fossiliferous deposits. Although the "middle shale" usually grades upward into fossil-rich shaley micrites of the "B" bed, the "A" bed often rests abruptly on dysoxic to anoxic dark shales as it does at this section.
The "A" bed is a prime example of what we term a "precursor" bed, a layer which records what appears to be a sediment-starved regression event linked to, but clearly preceding, a subsequent longer-term regression which culminates in fossil-rich, regressive, limestone, siltstone, and even sandstone facies (see text). Such beds are enigmatic in terms of existing models of cyclic sedimentation, because they are followed by apparent deepening events associated with synchronous and subsequent influxes of sediment which then produce a regressive filling sequence that culminates in the "B" unit (see text discussion).
At this locality the Stafford "A" Bed yields numerous small brachiopods, including Ambocoelia umbonata var. nana. Truncalosia truncata, Devonochonetes scitulus, and small variety of Tropidoleptus. Other fossils include the large bivalve Panenka, occasional Leiorhynchus, orthoconic nautiloids often encrusted by the reptate biserial tubular organism Reptaria stolonifera, which may have "hitch-hiked" on the living cephalopod (see Baird et al., 1989), and wood debris.
This faunal association is rather typical of precursor beds we have seen in other units and it is nearly identical to that associated with the lower Wanakah "Darien Center" cycle at nearby localities (see Miller, FIELD TRIP SUN C, this guidebook). The diminutive brachiopod assemblage in the Stafford "A" bed appears to represent only a slight increase in bottom oxygenation relative to the underlying Oatka Creek Shale. This assemblage falls between the "Leiorhynchus" and "Ambocoelia-chonetid" biofacies of Brett et al., 1986; Vogel et al., 1986; which is indicative of non-turbid upper dysoxic to minimally oxic bottom conditions (see text).

Cross Cayuga Creek
The lower calcareous part of the Middle Devonian Levanna Shale Member is exposed along creek near bridge. One particularly prominent ledge upstream (east) from the bridge yields occasional excellent enrolled specimens of the trilobite Phacops rana.

Cross Buffalo Creek at Elma, NY.
The Middle Devonian Ledyard Shale Member is exposed in the bed and banks of the creek. Pond Brook, a north-flowing tributary of Buffalo Creek just to the east of Bowen Road south of the bridge crossing has good exposures of the richly fossiliferous Wanakah Shale Member.

Cross the upper end of Pond Brook.

STOP 7. Condensed Carbonate Deposits Of Lower Moscow Fm.
Park near old bridge over Buffalo Creek. Walk out onto bridge for brief overlook, then proceed down bank at west end of bridge and walk about 100 feet north (downstream) to limestone exposure adjacent to the new Bullis Road bridge.
In the low stepped falls interval between the old and new Bullis Road bridges one can observe a succession of thin carbonate beds representing condensed facies of the lower Moscow Formation and uppermost Ludlowville Formation (Fig. 4B). The Tichenor Limestone is visible here as at STOP 2, but it is both overlain and underlain by additional limestone layers; the underlying layer is the basal Hill's Gulch Bed of the largely-bevelled Jaycox Shale Member of the Ludlowville Formation and the overlying beds are in ascending order, the thin, condensed phases of the Deep Run, Menteth, and Kashong members (Fig. 4B). In western Erie County the Jaycox is entirely absent and the overlying complex of condensed units is absent or nearly absent due to further westward bevelling, such that the Tichenor is directly underlain by Wanakah Shale and is overlain by the Windom Member (compare Figure 4A and Figure 4B).
Three discontinuities are present in this section; one at the base of the Hill's Gulch Bed which cuts into the Wanakah Shale; one below the Tichenor which cuts into the Hill's Gulch Bed, and one below the Windom Shale which bevels into a thin remnant of the Kashong Shale Member. The two lower discontinuities are marked by hypichnial, carbonate-casted burrow prods produced by arthropods excavating into underlying muds prior to burial of the discontinuity surface. The sub-Windom discontinuity is marked by phosphatic nodules, phosphatic steinkerns of Kashong fossils, and assorted shelly debris which have been churned and mixed by bioturbation processes during the onset of Windom deposition (Baird, 1978).
This condensed section is almost a "mirror-image" to that involving equivalent beds in central New York (Fig. 4c). Detailed mapping by Baird (1979), Baird and Brett (1981), Mayer (1989), Mayer et al. (1990) shows that each major bed in this outcrop has its time-stratigraphic counterpart in the condensed Jaycox-Kashong succession in the Owasco Lake-Ithaca region. Even the same discontinuities are represented in this latter area, though with the trend of increased bevelling and condensation in the eastward direction instead of westward, as is observed for the deposits here at Buffalo Creek. In the intervening Genesee Valley-Cayuga Lake region, each one of the component divisions in this section balloons into thicker, mud-dominated facies, with each respectively higher division -- Jaycox, Tichenor, Deep Run, Kashong reaching maximum thickness west of that for the previous division (Brett et al., 1986). Hence, this intervening region records a westward-shifting depocenter and an aggregate maximum thickness for the Jaycox-Kashong interval exceeding 35 meters (110 ft.)!
Thus, the "mirror-image"-stacking of corresponding condensed beds in these widely-separated regions is all the more significant given the complexity of depocenter shifts in the intervening region. It strongly suggests that eustatic sea-level changes were responsible for the succession of units, both within the depocenter areas, and on the adjoining shelf regions. Such a pattern makes all the more relevant the discussion of sequence stratigraphy applicability to the New York Devonian System (see text).
From the old Bullis Road bridge one can see the upstream bank of grey chippy Windom mudstone deposits. These rest on the sub-Windom (post-Kashong) phosphate debris-rich discontinuity which can be reached below water-level just upstream from the bridge foundation. Near the top of the Windom bank, the Bayview Coral Bed and the overlying Smoke Creek Bed can be seen. Enrolled Phacops rana can be collected from the Smoke Creek Bed further upstream in the floor of the creek. The giant blastoid Placoblastus sp. is a rare find at this locality; it occurs in the Deep Run-Menteth ledges above the Tichenor.

Cross Little Buffalo Creek.
Middle-Upper Devonian disconformity is exposed downstream from (to northwest of) road crossing.

STOP 8. Middle-To-Upper Devonian Condensed Basinal Deposits
Cross Cayuga Creek. Pull off on to driveway of first house on right beyond the bridge or onto right shoulder of Clinton Road if parking space is limited.
(See also Brett and Baird, 1982: , NYSGA Buffalo, meeting).
At this section ,we will first examine the Leicester Pyrite and its relationship to synjacent beds and then we will focus on the North Evans bone-conodont bed which marks the base of the Genundewa Limestone above the last falls riffle about 120 feet upstream from the bridge.
As with the lag deposit we observed below the Dunkirk at STOP 1, the Leicester Pyrite Member of the Genesee Formation is a detrital pyrite-bone-lag accumulation which directly underlies a laminated black shale unit (Geneseo Shale Member) and which occurs on a submarine discontinuity marking the base of the Geneseo. However, the Leicester is a more dramatic example of this lag type because it is made up of coarser grains and it is typically much thicker than the Dunkirk pyrite bed. Moreover, it rests on the Middle Devonian Windom Shale Member which is a grey mudstone unit usually rich in shelly fossils.
The Leicester is composed of pyrite burrow tube fragments, pyrite nodules, and pyrite fossil steinkerns derived from the Windom Member plus fish bone-and conodont debris of Windom and post-Windom age. These were exhumed under conditions of submarine anoxia or temporary dysoxia by episodic strong currents of unknown character. Reworked Windom (and Tully) lag debris was initially carbonate-dominated reflecting the overall calcitic and aragonitic character of Windom fossils. However, this carbonate debris underwent selective dissolution in a negative pH (or carbonate undersaturated) basin setting; a continuous blanket of reworked Windom carbonate debris, resembling the North Evans deposit at STOP 2, would hypothetically have been reduced to a placer lag of pyrite and bone debris only a small fraction of the original volume. Hence, the laterally discontinuous Leicester lenses represent only a remnant fraction of total Windom debris which was exhumed (Baird and Brett, 1986A). In actuality, during Geneseo time,no continuous carbonate debris blanket probably ever formed because dissolution would have removed carbonate as it was exhumed, allowing no carbonate to build up on the surface.
At this section as at other Leicester localities, some Leicester debris lenses occur within the basal Geneseo, not just at the base. This indicates that pyrite clast-transport occurred during the period of initial black mud accumulation. Moreover, conodont examination by Huddle (1981) shows that the age of the youngest (Genesee-age) conodonts in the Leicester becomes progressively less as this unit is traced westward from the Seneca Valley into eastern Erie County; this westward progressive overlap of Geneseo black mud and lag debris onto the widespread Windom-Genesee disconformity surface tracks the major Taghanic Onlap Event which is now believed to mark a major eustatic transgression in the late Givetian (Johnson, 1970). This overlap cannot be followed westward indefinitely; the sub-Genundewa discontinuity oversteps all lower Genesee strata in central Erie County and the Leicester is apparently cannibalized by this younger erosion surface between Cazenovia Creek and the north branch of Smoke Creek, southwest of Elma, Erie County (Brett and Baird, 1,982; Baird and Brett, 1986A).
Evidence for reworking of Windom Pyrite clasts includes: 1. identical character of Windom and Leicester pyrite grains; 2. evidence of mechanical breakage of pre-formed pyrite grains; 3. abundance of pyritic Windom fossil steinkerns in Leicester; and 4. the reorientation of early diagenetic stalactitic pyrite which formed initially in voids within in-situ Windom pyrite tubes and steinkerns (see Baird and Brett, 1986a, b). Ongoing laboratory sulfur isotope studies indicate a hodgepodge pattern of variable isotopic weights between adjacent pyritic grains which further suggest exhumation and mixing of the pyrite material (see Lyons, 1990).
The mechanisms for physically exhuming and reworking pyrite in what would normally be thought of as a euxinic environment are difficult to reconstruct, given that there is no known modern example of this specific marine condition. Deep-storm waves are always a possibility as are various possible bottom current processes. Baird and Brett (1986A) Baird et al. (1988), offer an erosion model involving transgressive upslope migration of a water density-stratification boundary (pycnocline) along which storm generated internal waves are propagated. Impingement of the pycnocline with the basin slope at an given time allows for the presence of a higher energy wave-shoaling zone coincident with the slope-pycnocline intersection producing a swath of bottom erosion at a critical water depth/contour. Continue transgression would displace the wave-shoaling zone upward allowing basinal black muds and associated bone-pyrite debris to settle on the scour surface produced during earlier internal wave-shoaling. Overall westward Geneseo black mud overlap of the erosion surface may have been interrupted by brief episodes of major current flow and bottom scour events; these may explain the occurrence of Leicester lenses which are interbedded with basal Geneseo black shale deposits.
The Windom-Geneseo contact is a regional disconformity (combined sequence boundary, transgressive and down lap surface) which overlies different Windom beds at different western New York outcrops. Generally, towards the north, the unconformity truncates progressive lower Windom beds. Conversely, towards the south, progressively higher Windom layers appear beneath the Leicester-Geneseo contact (Brett and Baird, 1982). At Cayuga Creek one can observe a Windom shell-rich bed become progressively truncated as it is traced from the falls south of the bridge northward. Near the falls, this Mediospirifer and Pseudoatryparich mudstone layer, probably equivalent to the Fall Brook Coral Bed in the Genesee and Wyoming valleys, is well developed (Baird and Brett, 1983).
Above the Windom-Genesee contact there are approximately eleven feet of organic rich black shale, dark grey shale, and concretion-bearing horizons which comprise the lower part of the Genesee Formation. This sequence of largely anoxic and minimally dysoxic basinal facies is extremely condensed; at Ithaca, New York, the equivalent stratigraphic interval is in excess of 150 m (500 feet) (deWitt and Colton, 1978; Baird and Brett, 1986A). Fossils which can be collected from the basal three feet of the Cayuga Creek Geneseo section include current-aligned Styliolina, the brachiopod Devonochonetes, and scattered wood fragments.
At the highest falls, dark, organic-rich and conspicuously laminated beds of the Penn Yan Shale Member are abruptly overlain by the 20-25 cm (8 to 10 inch) thick ledge of the Genundewa Member and its associated 1-2.5 cm (0.5 to 1.0 inch) thick basal lag veneer of North Evans reworked pelmatozoan, conodont, and bone debris. Further east in Genesee County, this lag unit apparently disappears and the base of the Genundewa become conformable. Although the North Evans at this locality is a bit less conspicuous than it is at STOP 2, it still yields glauconite-coated reworked concretions and a great abundance of conodonts. As at STOP 2, the Genundewa is a dense, grainstone to packstone blanket accumulation of Styliolina shells. The grotesque Penn Yan concretionary bed below the North Evans contact is also developed at other adjacent sections; it may have formed as a geochemical response to the proximity of the North Evans erosion surface which was being scoured out from above.

SunB: STRATIGRAPHY, STRUCTURAL GEOLOGY, AND HYDROGEOLOGY OF THE LOCKPORT GROUP: NIAGARA FALLS AREA, NEW YORK
DOROTHY H. TEPPER
Water Resources Division
Ithaca, New York 14850
WILLIAM M. GOODMAN
MICHAEL R. GROSS
Pennsylvania State University
University Park, PA. 16802
WILLIAM M. KAPPEL
RICHARD M. YAGER
The Niagara Falls area is known for its classic geology. An internationally recognized stratigraphic sequence of uppermost Ordovician and Silurian rocks is exposed along the walls of the Niagara Gorge. Summaries of the geology of this area are provided in Tesmer (1981) and Brett and Calkin (1987).
The purpose of this field trip is to provide an overview of some current research on the stratigraphy, structural geology, and hydrogeology of the Upper Silurian Lockport Group, which caps the section exposed in the Niagara Gorge. There has been much recent interest in the Lockport Group, particularly in the Niagara Falls area, where ground water within it has been contaminated by hazardous waste. In 1987 the U.S. Geological Survey (USGS), in cooperation with the U.S. Environmental Protection Agency (USEPA), began a 4-year study of the hydrogeology of the Niagara region. The primary objective of this study is to define the regional ground-water flow system so that a three- dimensional ground-water flow model can be constructed that can provide a regional hydrogeologic framework for future site-specific research efforts.
The U.S. Geological Survey recognizes "Lower," "Middle" and "Upper" Silurian and designates the Lockport Group as Middle Silurian. However, in a New York State Geological Survey publication by Rickard (1975); the use of "Middle" Silurian was abandoned in New York and was replaced with the terms "Lower" and "Upper" Silurian to be consistent with European usage. The Lockport Group is designated as Upper Silurian by Rickard (1975) and will be referred to as such in this paper."

SunB: STRATIGRAPHY, STRUCTURAL GEOLOGY, AND HYDROGEOLOGY OF THE LOCKPORT GROUP: NIAGARA FALLS AREA, NEW YORK

STOP 1. Frontier Stone Quarry
The First stop will be at the Frontier Stone Quarry in the Town of Gasport, where we will examine the stratigraphy of the Gasport Limestone, the lowermost formation in the Lockport Group. This quarry is located along a reentrant on the Niagara Escarpment we we will also examine changes in joint orientations along this feature.

STOP 2. Niagara Stone Quarry
The second stop will be at the Niagara Stone Quarry in the Town of Niagara, where we will examine the Lockport Group stratigraphy from the base of the Gasport Limestone to the upper part of the Eramosa Dolomite (previously termed the "Oak Orchard Dolomite"). We will also discuss fractures and large-scale "pop-ups" on the quarry floor.

STOP 3. Electromagnetic and hydraulic test site
The final stop (also in the Town of Niagara) will be at a site where the USGS has conducted detailed electromagnetic surveys and hydraulic tests as part of the USGS/USEPA regional hydrogeologic study. This stop will include a demonstration of electromagnetic techniques, including terrain conductivity and VLF (very low frequency), and a discussion of downhole instrumentation and the cross-hole hydraulic testing program that has been conducted at the site.

SunC: PALEOECOLOGY AND SEDIMENTOLOGY OF MIDDLE DEVONIAN SHORT-TERM SEA-LEVEL FLUCTUATIONS RECORDED WITHIN THE WANAKAH SHALE MEMBER OF WESTERN NEW YORK
KETIH B. MILLER
Department of Earth Science
Clemson University
Clemson, South Carolina 29634
The fine-grained sediments of the Middle Devonian Hamilton Group, deposited within the northern tongue of the storm-dominated Appalachian Basin, have proven to be an excellent testing ground for many paleoecologic and stratigraphic concepts as demonstrated by many past NYSGA guidebook articles. The extensive stream and lake shore outcrop exposures, relatively undisturbed "layer cake" stratigraphy, and well-preserved benthic faunas of the Hamilton Group in western and central New York are ideal for detailed sedimentologic, paleontologic, and taphonomic studies. Such studies have begun to uncover the wealth of information contained within the superficially homogeneous mudrocks and thin limestones of the Hamilton Group.
Fossil taphonomy is an important, if not vital, source of data for the interpretation of depositional environments, particularly within fine-grained rocks lacking obvious sedimentary structures. The relative effects of the post-mortem processes of reorientation, disarticulation, fragmentation, corrasion and encrustation upon various skeletal materials yields considerable information on rates of burial, exposure time, and degree of physical reworking (Brett & Baird, 1986a). Comparison of these taphonomic features from bed to bed or outcrop to outcrop enables subtle environmental gradients to be discerned (Norris, 1986).
As attention has been drawn to the details of individual shell beds, their storm-event origins have increasingly been recognized in shallow shelf settings. Using individual storm event-beds as building blocks, a temporal hierarchy of physical processes and biological responses can be reconstructed, from the scale of single beds to the ordering of facies sequences within an entire depositional basin (Aigner, 1984, 1985). Internally, shell beds record the complex short-term interactions of episodic storm-generated physical disturbance, substrate consistency, and benthic community composition (Miller, et al., 1988). Onshore-offshore gradients in the relative frequency, sedimentologic character and fossil taphonomy of storm beds enables relative water depths to be determined (Brett et al., 1986a). In addition, widely traceable storm event-beds or packages of event beds possessing distinctive taphonomic and faunal signatures can be used as isochronous markers for very high-resolution correlation. At a yet greater temporal scale, cyclic patterns in the taphonomy and faunal composition of shell beds reflect sea-level fluctuations at several temporal scales (Savarese et al., 1986; Brett and Baird, 1986b; Miller, in press). These cycles afford a potentially valuable means for correlation since the positions of maximum regression and transgression provide basinwide isochronous markers. The character of these cycles also provides a very important clue to the dynamics of deposition within the northern Appalachian Basin during the Middle Devonian.

SunC: PALEOECOLOGY AND SEDIMENTOLOGY OF MIDDLE DEVONIAN SHORT-TERM SEA-LEVEL FLUCTUATIONS RECORDED WITHIN THE WANAKAH SHALE MEMBER OF WESTERN NEW YORK

STOP 1. Elevenmile Creek At Darien Lakes State Park
The streambank exposure along Elevenmile Creek within the Darien Lakes State Park is the type locality of the Darien Center Submember. The entire 4-meter stratigraphic interval is well exposed here, and the major key beds can be easily recognized at the outcrop. We will use this stop to become familiar with the distinctive character of each of the various key beds discussed in the text. This locality provides an excellent opportunity to closely examine the vertical sequence of shell bed types and fossil assemblages characteristic of the Darien Center Submember.
Figure 11 displays the presence/absence macrofaunal data for this locality. This data reveals a nearly symmetric pattern, interpreted as reflecting a regressive-transgressive eustatic sea level cycle. The higher faunal diversities of the transgressive half of the cycle probably reflect lower turbidity conditions, and are associated with more closely spaced and more condensed shell beds.
Near the center of the cyclic sequence is a prominent biostromal coral bed. Named the Darien Coral Bed, it attains its best development at this locality, and is dominated by the branching tabulate coral Eridophyllum. At Buffalo Creek (Stop 2) to the west, this same coral bed is represented only by widely scattered Heliophylum and Cystiphylloides corals. Along the outcrop belt to both the east and west of Elevenmile Creek, the Darien Coral Bed thins and becomes a horizon of scattered rugose corals before ceasing to be a recognizable marker bed (see Fig. 4 in the text).
NOTE: NO COLLECTING IS PERMITTED ON THE PROPERTY OF THE DARIEN LAKES STATE PARK.

STOP 2. Buffalo Creek At Girdle Road Bridge
A continuous cut bank on the south side of Buffalo Creek to the west of the Girdle Road bridge exposes the entire Darien Center Submember for a distance of over 500 meters. At this locality, the Darien Center cycle is only 3 meters thick and the transgressive half is highly condensed. The presence/absence faunal data of Figure 12 shows this asymmetry and also reveals the sudden diversity changes associated with traceable key beds. These distinctive marker horizons represent subcycle boundaries and are the basis for correlation across western and central New York State.
At the base of the Darien Center Submember is a peculiar discontinuity surface which is especially well displayed at this locality. This discontinuity is represented by the undulatory Stolle Road Bed which repeatedly separates from and merges with the underlying Mt. Vernon Bed defining a series of mudstone lenses of varying amplitude and width (see Figs. 8 and 9 in text). The mudstone lenses, or what I call "swells," are elongate features trending at a high angle to depositional strike. Dense shell layers dominated by the tiny brachiopod Ambocoelia occupy the broad flat "channel" areas between the swells. These shell layers extend up the flanks of the swells, becoming thinner and progressively losing fossil taxa. Over the tops of the swells the discontinuity is often represented only by a horizon of pyritic burrow tubes and pyrite nodules. The geometry of the swells and channels, and their approximately onshore-offshore orientation, suggest an analogy with modern sedimentary furrows produced by helical flow cells within episodically flowing bottom currents. This irregular erosion surface was formed during the early regressive phase of the Darien Center cycle, and may record an accentuated regressive pulse produced by a superimposed subcycle.

STOP 3. Lake Erie Shore North Of Eighteenmile Creek
After only a few hundred feet (before the bridge) turn right onto gravel drive and park in privately owned gravel parking area. Walk across the bridge over Eighteenrmle Creek and then proceed toward the lake shore along the north bank. At the mouth of the creek walk north along the lake shore
This beautiful cliff exposure provides access to the upper transgressive half of the Darien Center Submember which alone is about 3 meters thick. The lower portion of the section is below lake level at this locality. The closely spaced shell beds can be easily examined and sampled here, and fossil collecting is excellent. Figure 13 shows the presence/absence faunal data for these lake shore cliffs.
The major key beds are easily recognized here. Especially well displayed at and near the lake level are the Lakeview Bed and the underlying shell beds containing abundant Pleurodictyum corals. Exposed bedding plane surfaces of these beds reveal well preserved in situ fossil assemblages on shell bed tops. Articulated and life position brachiopods are abundant, and complete trilobites and camerate crinoids can often be found. These fossils represent smothered epifaunal communities which had colonized winnowed shell hash layers. The shales overlying the shell beds are nearly barren of fossils and probably represent muds rapidly deposited by storm events. These muds were likely responsible for the preservation of the underlying shell beds by removing them from the sediment/water interface where taphonomic loss is great, and by stimulating early diagenetic pyritization and carbonate concretion formation.

SunD: (continuation of) EURYPTERID BIOFACIES OF THE SILURIAN-DEVONIAN EVAPORITE SEQUENCE: NIAGARA PENINSULA, ONTARIO, CANADA AND NEW YORK
For the past 28 years, I have been studying eurypterids, their stratigraphic occurrence, distribution, and associated flora and fauna, particularly in northeastern United States and Ontario, Canada. In New York the best known eurypterid assemblages are: 1) the Eurypterus remipes Fauna of the Fiddlers Green Formation that includes the earliest discovery of an eurypterid on this planet (by Dr. Mitchell in 1818); 2) the younger Eurypterus lacustris Fauna of the Williamsville Formation of western New York and Ontario, Canada; and 3) the eurypterid fauna of the Shawangunk Formation southeastern New York.
The search for new eurypterid faunas and the study of their geographic distribution in the Siluro-Devonian rocks of the region is important for several reasons. Foremost is the fact that the eurypterid faunas are punctuated within the known stratigraphic sequences. New genera appear suddenly within the sequences, e.g. Waeringopterus Zone, Erieopterus Zone, etc. When an eurypterid species disappears from the record completely, it is easily understood and we often assume extinction. The sudden appearance (or ecological replacement) of a species by an unrelated forms, (such as the Silurian Eurypterus being replaced by Erieopterus in the Early Devonian, is much more difficult to decipher. Only continued search for intervening occurrences, stratigraphically and geographically, will provide the data needed to understand the evolution of the eurypterids and their assemblages.
A second factor of significance concerns the eurypterid assemblages. Generally, where eurypterids are found there is a conspicuous absence of other fossils, in number and especially in diversity. Hence, the stratigraphic sequence is often considered to be unfossiliferous. The evaporite-bearing Salina Group is notable of this designation. Precise correlation, regionally and inter-regionally is needed to achieve a more complete understanding of these unique invertebrates. See Figure 1 for a map showing areas having exposures of Late Silurian-Early Devonian strata.

SunD: (continuation of) EURYPTERID BIOFACIES OF THE SILURIAN-DEVONIAN EVAPORITE SEQUENCE: NIAGARA PENINSULA, ONTARIO, CANADA AND NEW YORK

STOP 1. Section high in Lockport Group
("Oak Orchard" of Zenger). Large stromatolite mounds.

STOP 2. Ellicott Creek Breccia
Type Sections: Ellicott Creek Breccia, Williamsville Waterlime.
Figure below shows stratigraphic section of part of Bertie Group.

View from escarpment on left-WHEW!

STOP 3. Fiddlers Green Fm. Etc
Inactive quarry exposing a portion of Fiddlers Green Fm. up through Cobleskill Fm. Large quarry in Onondaga Limestone just to the east.

STOP 4. Indian Falls-Falcon Crest
Falls consists of massive Victor Dolostone - lush green algal mats still thrive on bedding planes, in pools and channels. No eurypterids have been seen.

Neat boulder on left

Genesee LeRoy Stone Quarry on Right

STOP 5. Stratigraphic section
Stratigraphic section showing Camillus Shale (Salina Group) and overlying Fort Hill Waterlime.

Dolomite Products Co., Inc. LeRoy Plant.
Old locomotive ensemble, quarries in Onondaga.

Erratics of Victor Dolostone
Note Whitfieldella brachiopods littering bedding planes.

STOP 8. Neid Road Quarry (Ciurca, 1973).
Bertie Group and overlying Onondaga Limestone exposed here.

STOP 9. TURN RIGHT into Oatka Park.
Exposures of Syracuse Fm. (Salina Group) along Oatka Creek. Ruins of buildings-old gypsum mines.

SunE: SHALLOW WATER REEFS OF THE MIDDLE DEVONIAN EDGECLIFF MEMBER OF THE ONONDAGA LIMESTONE, PORT COLBORNE, ONTARIO, CANADA
THOMAS H. WOLOSZ
Center for Earth & Environmental Science
SUNY College at Plattsburgh
Plattsburgh, N.Y. 12901
The reefs of the Edgecliff member of the Onondaga Formation are a well known part of the geology of New York State and the Niagara Peninsula in Ontario, Canada. Over the past thirty to forty years, the Onondaga and its reefs have been the subject of a number of Master's theses and Doctoral dissertations (see Wolosz, 1984, for references), and yet there are still a large number of unanswered questions regarding these reefs and the Onondaga in general.
The Edgecliff has generally been assumed to represent a warm, tropical, shallow water environment due to its abundant and diverse coral fauna. However, the lack of stromatoporoids and calcareous algae is a notably unusual feature for Devonian reefal limestones. The absence of these organisms led Kissling and his students (Kissling, 1987; Kissling and Coughlin, 1979; Cassa and Kissling, 1982) to interpret these reefs as deep water structures. They have also pointed to the absence of peritidal facies in the Onondaga as added support for this interpretation, suggesting that the preserved Onondaga represents a deep water facies, the shallow water facies which rimmed the basin having been removed by erosion.
Studies of other Edgecliff reefs have yielded results which do not support this interpretation. The Thompson's Lake bioherm has been interpreted as having grown into the surf zone (Williams, 1980), while the LeRoy Bioherm has been interpreted as a shallow water deposit by Poore (1969), Lindemann (1988), and Wolosz (1988). Wolosz (1984, 1985) presented evidence of coral breakage and overturning to argue for shallow water conditions during reef growth at Roberts Hill and Albrights Reefs.
This field trip will examine the Ridgemount and Quarry Road bioherms, which are being interpreted by the author as the shallowest water reefs known from the Onondaga.

SunE: SHALLOW WATER REEFS OF THE MIDDLE DEVONIAN EDGECLIFF MEMBER OF THE ONONDAGA LIMESTONE, PORT COLBORNE, ONTARIO, CANADA

STOP 1. Ridgemount Bioherm
HARD HATS REQUIRED Please beware of overhangs and loose rock. NOTE: Visitors should sign in at the quarry office 0.8 miles to the north.
Figure 4A is a map of the Ridgemount Quarry. Note that reef facies are restricted to the northeastern quarter of the quarry. The north wall of the quarry exposes a number of bioherms (Satellite bioherms), while a single bioherm can be examined in the east wall, just north of the water filled section of the quarry (Bioherm A). The northeast wall of the quarry displays abundant coral in a bed which pinches and swells from about 0.7 to roughly 2 meters thick (Coral Beds).
Cassa and Kissling (1982) interpreted the Edgecliff in this quarry as consisting of numerous small bioherms, which is, to a large degree, correct. However, it is important to note the dip of the beds which overlie this coral bed (in particular the quarry walls surrounding tank cars on Upper Level). These exposures are above and to the east of the Coral bed exposure, but they are already dipping westwards, indicating that these small mounds existed behind a larger structure to the east. While the dip has to some degree been enhanced by compaction (especially around Bioherm A), a pinch out of these beds can be observed along the north wall of the quarry, indicating a primary depositional dip. Further, examination of the beds behind the tank cars reveals numerous thickets of Acinophyllum and small branching tabulate corals. These thickets have not been observed elsewhere in this quarry, suggesting colonization of a topographic high on the sea-floor. Finally, note the top of the quarry wall (good exposures may be found along the quarry rim above the tank cars, also above Bioherm A) which consists of a clean biostromal sand containing large phaceloid rugosan colonies (Cyathocylindrium?) and abundant solitary rugosans and favositids. This facies appears to be restricted to the general vicinity of the stratigraphically lower coral buildups, also supporting the presence of a topographic high on the sea-floor.
Examination of the coral buildups (Bioherm A, satellite bioherms, coral beds) reveals little internal structure. Unlike the well developed rugosan thickets commonly found in thicket/bank structures or the dense growth of colonial corals within mound structures (as will be seen at the Quarry Road bioherms), these buildups are most commonly characterized by debris and· overturned and broken coral colonies (large overturned favositids are especially notable). Bioherm A (Figure 5) is easily accessible for examination. Note the absence of a well developed core facies in this structure. This unusual lack of internal structure is interpreted as indicative of very shallow water conditions during mound development. Intermittent high energy periods (storms) prevented the continuous coral development seen elsewhere in the Edgecliff, and resulted in the debris-mound facies seen in this quarry.
A proposed model of the coral mounds and beds present in the Ridgemount Quarry is presented, in Figure 48. In this model, initial colonization of the shallow sea-floor lead to the development of small debris mounds (little in-place growth is preserved due to the battering of these mounds by waves). These debris mounds acted as sites for further colonization by rugosans, and as protection for tabulate corals colonizing the sea-floor to the lee of these mounds. Gaps between mounds would fill with storm generated debris, and then be recolonized by coral, eventually leading to the formation of an elongate "Coral Ridge", with small satellite bioherms in a back-ridge biostrome.
No other Edgecliff reef exposure exhibits such extensive evidence of storm damage, suggesting a shallower water depth than any other known structure. Further, evidence of the early growth of this structure following transgression over the exposed Bois Blanc (and therefore shallow water conditions) can be seen along the north wall of the quarry, to the west of the last satellite bioherm. There, the carbonate sand facies extending from the satellite bioherm interfingers with the basal "Springvale Sand", indicating that the growth of the satellite mound was coeval with the deposition of the "Springvale" only a few meters to the west.
Ancillary Topics at Stop 1. The west wall of the quarry exposes the Siluro-Devonian disconformity described by Kobluk, et al. (1977). This contact is characterized by borings which have been filled by quartz sand and glauconite. The underlying Silurian dolomite contains brecciated horizons. Excellent samples are available for class use. Finally, possible teepee structures are present in the Bois Blanc just below the contact with the Onondaga (see map Figure 4A).

Stop 2. Quarry Road Bioherm
The West Quarry (Figure 6A) offers examples of two types of Edgecliff Reefs. Along the north wall two small, mono-generic mounds and some quarried blocks of mound facies are available for examination. The easternmost mound (and the bioherm blocks) consist of Acinophyllum colonies, while the western mound is predominantly Syringopora. Unlike the bioherms at Ridgemount these small structures exhibit dense, in-place growth of colonial coral.
At the south end of the quarry, exposed on a glaciated surface, are three small thicket/bank structures (Figure 68) the largest of which is approximately 26 meters in diameter. These small mounds are made up of thickets of phaceloid colonial rugosans interbedded with biostromal beds of small branching tabulate corals. Again, compare the in-place preservation of coral in these small structures to the debris mounds at the Ridgemount Quarry, keeping in mind that we are now roughly 3 kilometers down depositional dip from the Ridgemount structures. Also note that these structures are quite small when compared to other thicket/bank reefs such as the roughly 245 meters diameter North Coxsackie Reef south of Albany and the approximately 300 meters diameter Buffalo Country Club Reef (bioherm #'s 3 and 28 of Oliver, 1976).
Finally, examine the grainstone bed along the northeast and east wall of the West Quarry. Stromatoporoids have become quite abundant in this facies, and can also be occasionally found in the underlying, muddy Cystiphylloides biostrome.
Ancillary Topics at Stop 2. The Bois Blanc Formation floors both the East and West Quarries. Fossil collecting is excellent, with the quarry floor littered with loose rugosans, tabulate corals, and other fossils.

SunF: A FRESH LOOK AT THE SEDIMENTS WITHIN THE TERRACES AND CLIFFS THAT PARALLEL THE LAKE ERIE SHORE IN ERIE COUNTY, PENNSYLVANIA
DAVID THOMAS and RAYMOND BUYCE
(Mercyhurst College)
The lake plain adjoining the coastal bluffs of Lake Erie in Pennsylvania is comprised of two to three major southwest-northeast trending terrace systems. They form a stair-step arrangement of very gently sloping. terraces each bounded on the north by slightly to precipitously steeper escarpments or cliffs. The edges of these terraces have been referred to as "beach ridges"by several early workers (e.g. Leverett, 1892). Extensions of the terrace margins in Ohio and elsewhere are actually ridge-like although their beach origin has been questioned. Each relatively flat terrace level is reliably attributed to deposition associated with a corresponding lake level of a Pleistocene precursor to Lake Erie. It is still an open question whether the environment of deposition for any particular terrace or part thereof can be justifiably ascribed to beach deposition or whether a braid-plain (saridar), delta, or some other setting might have been responsible. Some of the early work relied heavily upon topographic expression to seek answers to the questions of origin but on this trip we will have the opportunity to look at two fine exposures within the terraces to see if the sedimentological evidence is more definitive.
Exposed in the gravel pit at the first stop is the uppermost of the two terraces present along the southeastern part of the Harborcreek 7 1/2 minute quadrangle. The upper terrace is attributed to sediment deposition associated with Lake Whittlesey (elevation: 740 feet, age: 13,000 yr B.P.). Our second stop is on the shore of the modern Lake Erie where the upper approximately 70 feet of bluff exposes the sands and gravels which underlie the lowermost of the two terraces. These sediments are ascribed to deposition associated with Lake Warren which was both lower and later (elevation: 675. age: 12,000-13,000 yrs B.P.) Also exposed underlying the sands and gravels in the bluff at this location is more than 100 feet of glacial till (periglacial? diamict). To enable you to better orient yourself geologically a brief description of the geology of the field trip area is provided below.

SunF: A FRESH LOOK AT THE SEDIMENTS WITHIN THE TERRACES AND CLIFFS THAT PARALLEL THE LAKE ERIE SHORE IN ERIE COUNTY, PENNSYLVANIA

We will cross Seven-Mile creek
We will cross Seven-Mile creek, an essentially north-flowing creek that empties into Lake Erie. Seven-Mile refers to the distance of the creek and the city of Erie to the west, and not the length of the creek.

You will be traveling across the Ashtabula Morainic System.
The Girard and Ashtabula Moraines which are easily distinguished south of Erie, PA cannot be recognized at the two separate ridges east of Erie, Ashtabula till Halburn, PA.

Overlook.
Ahead is the steeply descending North-facing slope of the Ashtabula Moraine and the flatter lying terraces of lakes Whittlesey, Warren I-II and Warren III.

We continue to descend the north-facing slope of the Ashtabula ice marginal moraine.

North facing slope of the Ashtabula Ice Marginal Moraine.
We will be traveling east on and parallel to the north facing slope of the Ashtabula Ice Marginal Moraine.

We will be descending a much gentler north slope of the Ashtabula Moraine.

We'll remain on Ashtabula deposits.

We cross a west-flowing tributary of Twelve-mile creek.
The stream has cut into stratified, subangular to subrounded cobbles with an occasional glacial erratic. The material has not been extensively worked.

We will descend a relic "wave cut" cliff of Lake Whittlesey
We will descend a relic "wave cut" cliff of Lake Whittlesey and proceed north across much flatter terrain. The terrain is underlain by gravel of a variety of sizes.

To our right (north) is the lake Warren I terrace.

The cemetery to our left illustrates the true topography.
Large amounts of gravel have been quarried from both sides of the cemetery.

STOP 1. Central Sand And Gravel Pit
(Stop description by: Charles Carter, Univ. of Akron from Thomas and others, 1987)
This pit is part of an extensive (several kilometers long and up to a few kilometers wide) sand and gravel deposit that trends southwest-northeast, roughly parallel to the present Lake Erie shore (Figure 14). The existing pit is nearly mined out as are adjacent pits to the west and south. The sand and gravel are used for road construction, the mining is done with front-end loaders, and the processing is accomplished by a hydraulic sorter. The deposit is at least 8 m (26 ft) thick and mining has been done to 5 or 6 m (16 or 20 ft) below the original, prestripped surface. Foreman Scott Wassink said that the deposit was coarser to the east so that although the sediments exposed along the western face are largely granule- and pebble-sized, the overall grain size for the pit was larger.
A small, about 4 m (13 ft) long, normal, nearly bedding-plane parallel fault occurs near the center of the face. The apparent fault plane is curved and has a strike of about east-west and an overall dip of about 23 N although siltstone cobbles are oriented nearly 90° from the horizontal at the north end. Whether the origin of the fault is tectonic or isostatic is unknown.
The elevation of the surface of this deposit (about 780 to 790 ft), and the correlation of this surface both to the east and the west, has led to the mapping of this feature and elevation as the Whittlesey strandline (Schooler, 1974, p. 11, 12). The deposits underlying this surface in this area of Pennsylvania have been interpreted as "beach deposits" (most recently by Schooler, 1974, p. 19) mainly on the basis of geomorphic evidence. However, she also recognized a "channel-like feature" at one location that included imbricated gravel that she interpreted as a "delta" (p.22). Schooler's work is typical of most of the work that has been done on the "beach ridges," in that the interpretations of these deposits have been made largely on topographic expression and texture with little consideration given to the internal characteristics and geometry of the deposits. Because of this, University of Akron students and faculty are doing sedimentologic studies of the ridges in order to improve our knowledge of their origin and evolution.
Sedimentology and Paleogeography
The pit lies near the western apex of a triangular-shaped terrace that opens to the east (Figure 15). A north-south face with a length of about 350 m (1148 ft) and a mean height of about 4 m (13 ft) provides an excellent cross section of the deposit. There are three facies exposed in the face: an interbedded granule and pebble/cobble facies (about 80 percent of the face), a gravel lens facies (5 percent), and a turbated clay/gravel facies (15 percent) (Figure 16).
The interbedded granule and pebble/ cobble facies consists of thin to thick beds and lenses that dip gently to the north. The particles making up the individual beds or lenses consist almost entirely of well sorted, well rounded, disc-shaped, siltstone clasts. The individual beds and lenses of granule contain laminations and very thin beds that parallel the enclosing bedding planes. The laminations and beds are distinguished on the basis of slight textural differences, although internally they appear to lack grading.
The individual lenses of pebble/cobble consist of framework-supported clasts with long axes oriented parallel to the northerly dip of the surrounding beds. The majority of the lenses are made up of siltstone pebbles no more than a few centimeters thick and thin to single pebble thicknesses at the margins.
In general, the beds and lenses can be traced laterally for 10 to 20 m (33 to 66ft). The granule beds are thickest and most continuous, but the pebble/cobble lenses are up to 25 m (82 ft) and 20 cm (0.6 ft) thick. In places, the pebble/cobble lenses truncate the underlying granule at low angles. Overall, there is little if any lateral change in this facies from north to south, but vertically the facies fine upward in a 2-3 m (6-10 ft) section from fine pebbles to granules. The true dips of the sloping surfaces in both the granule and the pebble/cobble lenses are oriented between 305° (NW) and 15° (NE) with dips from 4° and 17° (the dips of 6 of the 7 readings lie between 4° and 7°). The dip orientations are not scattered. The 2 lowermost orientations are just east of north whereas the 5 uppermost orientations are to the northwest.
The gravel lens facies consists of flat to convex-up lenses that enclose cross-stratified beds of granules, pebbles, and cobbles In this facies, some of the long axes of the gravels lie parallel to the stratification and others do not. In two flat-topped lenses near the south end of the face, the shape of the cross-stratification resembles lateral accretion surfaces. In a major convex-up lens located about one-third the distance from the southern end of the face, the central part of the lens consists of tightly packed, imbricated gravels. Flanking the central zone are cross-stratified cobbles, pebbles, and granules that fine as well as steepen (11° to 27°) away from the center. There is no apparent change in the texture of the individual cross-stratified layers. A second, much smaller but coarser (mostly cobbles), convex-up lens lies about 30 cm (1 ft) above the larger lens. This lens lacks the cross-stratification of the underlying lens. In both lenses the siltstone cobbles dip uniformly in a westerly direction whereas the stratification flanking the major lens dips to the south.
The gravel-size clasts, as in the interbedded facies, are framework supported, although in both facies there are numerous discrete cobble and even siltstone boulders that occur here and there in the section, parallel to the stratification of the enclosing granules, and commonly in the same planes. The pebbles and cobbles in the lenses are mostly siltstone. However, at three scattered places, well sorted and rounded, more spherically-shaped, gravel-sized clasts of mixed rock types are found. A pebble count of 69 clasts from one of these gravel lenses showed the following: 53 percent siltstone, 23 percent sandstone, 20 percent igneous and metamorphic, and 4 percent carbonate clasts.
The gravel lenses can be traced laterally for 10 m (33 ft) or more with the major convex-up lens having a lateral extent of at least 30 m (98 ft). The lenses dip gently to the north and although there are no vertical changes in the lenses, nearly all of the lenses show an up-dip (south) decrease in grain size. The true dip orientations of the "cross-stratification" in the lenses lie between 160° (SE) and 190° (SW) with dips from 11° to 27°. The true dip orientation of the cobbles in one imbricated zone is 275° (NW) with a dip of 10°, and the unmeasured orientation of other imbricated zones is also to the west.
The turbated clay/gravel facies consists of pods of clay separated by contorted zones of granule/gravel. Most of the facies has been removed, but before the surface was stripped there was about 15 cm (0.5 ft) of soil underlain by about 75 cm (2.5 ft) of clay (Scott Wassink, personal communication).
In terms of facies association and order, the interbedded granule and pebble/cobble facies is eroded by the gravel lens facies, with a relief as much as 1 m (3 ft). There are about 6 gravel lenses along the face with the lenses occurring throughout the section in a vertical sense, and along the southern two-thirds of the face. The turbated clay/gravel facies caps the two underlying facies.
Interpretation
The northward-dipping, interbedded granule and pebble/cobble facies is interpreted as proximal Gilbert-type deltaic foresets. The gently dipping lenses represent deposition from grain flow and avalanching on the delta foreset because of flow expansion and deceleration at the river mouth. The coarser gravel lenses may have been segregated during avalanching and/or may represent higher energy, episodic events. Rapid deposition took place during homopycnal flow mixing (Nemec and Steel, 1984). The incomplete foreset thickness of .3 to 4 m ( 10 to 13 ft) indicate minimum water depths of 3 to 4 m (10 to 13 ft) at the river mouth. The overall fining-upward sequence in these deposits may be due to decreased flow strengths caused by a gentler gradient.
The cross-cutting, cross-stratified sands are interpreted as channel deposits. Incisions of the delta slope by distributary channels during episodic drops in water level, and subsequent rises in water level, may have caused this scour and fill type of structure.
The northerly paleoflows are consistent with a delta/coastal alluvial fan origin. Northward flowing streams coming off the steep isostatically uplifted glaciated uplands debouched into glacial Lake Whittlesey with little modification by waves. The high rate of bedload coupled with low wave energy allowed the deltas to build directly to the north.
Alternate hypotheses could include sandbar or barrier systems. However, the geometry of the deposit and the thickness and lateral extent of the interbedded granule and pebble/cobble facies make these hypotheses unlikely.

We will descend a short, steep slope onto an area of relatively low relief.
The elevation along Route 20 is about 780 feet. This is the edge of the Law-Whittlesey Terrace. The elevation at the bottom of the steep slope is 760 feet. This is the general elevation of the Lake Warren I-II level in the eastern section of Erie county. The slope is thought to be a relic wave cut cliff cut by the waves of Lake Warren I and can be seen running parallel to US Route 20 about 40 feet above it.

Cross a channeled west flowing tributary stream to Twelve-mile Creek.

We continue to cross the lake warren I Terrace.

STOP 2. Brickyard Road Section.
(Description by: Dave Thomas and Ray Buyce from Thomas and others, 1987)
This stop is located at the foot of a private, unpaved road that extends north of US Route 5 from Brickyard Road in the northeast section of the Harborcreek, PA 7.5-minute quadrangle (Figure 14). The property is owned by the McCord family, one of the pioneer vintners in the Pennsylvania-New York section of the grape belt. Permission must be obtained from the McCord family for access to the property. We will be examining the bluff-face exposures.
The summit of the bluff overlooking Lake Erie about 300 (1000 ft) from US Route 5 is dangerous! It is capped by non-cohesive sand that fails under very small additional loads.
DO NOT WALK TO THE BLUFF EDGE!
Landform
The summit of the bluff at this location is about elevation 700 feet. It is the location of the northern margin of a gently sloping terrace that can be traced south on Brickyard Road from elevation 730 feet at us Route 5 to elevation 770 feet just below US Route 20. We believe that this terrace represents a Lake Warren I level.
Stratigraphy
General. Wave erosion and a variety of mass wasting processes have exposed approximately 50 m (165 ft) of glaciogenic deposits represented by 2 distinct facies. The lower part of the section is a diamict facies which comprises 17.4 m (57 ft) or 35 percent of the total bluff height. The upper 33 m (108 ft) or 65 percent of the total bluff height is composed of a gravel and sand facies. Figure 16 presents a graphic display and Table 1 the detailed stratigraphic description of the measured section.
Diamict Facies. This facies may be divided into 2 distinct lithologic types based upon thickness and grain size distribution. The lower segment consists of 11 units (1 through 11, Measured Section) ranging in thickness from 0.06 m (0.2 ft) to 0.6 m (1.75 ft). These 11 units occur as 2 different lithologies. Six of the units are massive, matrix-supported diamicts composed of olive gray, clayey silt to very fine sand supporting angular to subrounded pebbles and rarer gray and reddish gray soft clay clasts. Thicknesses range from 0.07 to 0.53 m (0.25 to 1.75 ft). The other 5 units are laminar-bedded, clayey silt, silt, or very fine sand supporting angular to subrounded pebbles and rarer gray and reddish gray soft pebble-size clay clasts. The thicknesses range from 0.06 to 0.07 m (0.20 to 0.25 ft). These 2 lithologies consistently alternate up through the entire 2.2 m (7.25 ft) of this segment of diamicts. At the lower contact of the uppermost unit (11) are alternating dark and light gray, clayey silt laminae with a roll-up structure and folds overturned westward.
The upper diamict segment is 12.75 m (41.85 ft) thick and consist of 4 units (12 through 15) ranging in thickness from 1.3 to 5.3 m (4.25 to 17.25 ft). These 4 units are composed of olive gray, massive, clayey silt or very fine sand matrixes supporting angular to subrounded pebbles, and fewer cobbles and rare boulders. The angular cobbles are hard siltstones or very fine sandstones whose origins may be found in the Upper Devonian bedrock to the immediate east. The subangular to subrounded cobbles are either Lower Paleozoic sedimentary rocks plucked from the Ontario-Erie basin farther to the east or Precambrian crystalline igneous and metamorphic rocks transported from the Canadian Shield. The lower 2 units (12 and 13) show, at their lower contacts, roll-up structures and folds in laminar clayey silt beds that are overturned toward the west. In addition, there is a normal fault with 6 mm (0.25 in.) displacement in the rolled-up laminar beds near the base of Unit 12.
Gravel/Sand Facies. The diamict and gravel/sand facies is separated by a 0.15 m (0.5 ft) thick laminar-bedded clay with a thin sand bed at the base and top. The contact between the clay and gravel facies appears erosional. The gravel segment of the gravel/sand facies (Unit 17) is 6.6 m (21.65 ft) thick. It consists of angular to subrounded pebbles and interstitial sand and clayey silt. The lower part of the unit has 2 cut and fill channels. The beds of the lowest channel dip northwest, while the beds of the upper channel truncate those of the lower and dip northeast. Bedding is not apparent in the remaining upper part of the gravelly unit; however, discontinuous fine-grain drapes occur throughout. A continuous 2.5 to 5 cm (1 to 2 in.) drape separates the gravel from the sandy units above.
The sandy segment of the gravel/sand facies is about 20 m (66 ft) to the summit of the bluff. The upper 4.6 to 6 m (15 to 20 ft) were not measured because of steepness and instability of the slope. The sand units are composed of very fine, fine, and medium sand with relatively thin interlayers of clayey silt or very fine sand. The clayey silts or very fine sands occur as drapes.
The lowest unit (18) is composed of 0.46 m (1.5 ft) of very fine laminated sand displaying horizontal, trough, wavy, and flaser bedding and beds of horizontally laminated clayey silt.
The overlying unit (19) is 10.6 m (35 ft) thick. The lower 7 m (23 ft) is covered with sandy colluvium; however, exposures east and west of the Measured Section indicate lithologies consistent with the measured upper 3.7 m (12 ft) of the unit. The upper 3.7 m (12 ft) is composed of alternating beds of very fine sand and clayey silt beds. The laminar clayey silts are bedded horizontally while the very fine sand units display horizontal, trough, wavy, and flaser bedding. Pebble-size drop stones are sparsely scattered through the unit. The thicker sand beds in the lower part of the unit yield to clayey silt beds upward through the unit. This fining upward sequence is contorted by soft sediment deformation structures with amplitudes of 3 ft or more in its upper part. The remainder of the measured section (Unit 20) which is 20.1 m (66 ft) thick is composed of sand and clayey silt or very fine sand beds. The sand beds display laminar and thin horizontal, wavy, trough, and flaser bedding and climbing ripples. The clayey silt or very fine sand occurs as relatively thin drapes.
QUESTIONS
Questions to be asked at this stop are basically the same as those at stop 2:
1. What process(es) formed the diamicts?
2. Is there evidence of sublacustrine deposition and if so what mechanisms were involved?
3. Is there more than one age of diamict here? What approach could be utilized to resolve the problem?
4. How many different environments of deposition may be represented by these sediments?

We will be traveling across the Warren I-II Terrace
We will be traveling across the Warren I-II Terrace from elevation 740 feet to elevation 760 feet over the next 1.8 miles, a gradient of about 11 feet per mile.

Edge of Lake Whittlesey Terrace, just above the Warren I scarp (Wave cut?).
US Route 20 is straight ahead (south) running along the edge of Lake Whittlesey Terrace, just above the Warren I scarp (Wave cut?).

Lake Whittlesey Terrace with the Warren I-II Terrace to our left.
We are now traveling on the Lake Whittlesey Terrace with the Warren I-II Terrace to our left.

SunG: PADDLING UP A MELTWATER CHANNEL: A LATE-WISCONSINAN ICE-MARGINAL CRUISE NEAR FREDONIA, NEW YORK
Randy J. Woodbury and Michael D. Jensen
Fredonia, N.Y. 14063.
Although the area near Fredonia was glaciated several times during the Pleistocene (see, for example: Leverett, 1902; Fairchild, 1907; Muller, 1963, 1977; Muller and Fahnestock, 1974; Schooler, 1974; and Cadwell, 1988), it was the most recent Late Wisconsinan ice margins, active here between 14,000 and 12,000 years B.P. (Calkin and Feenstra, 1985), that left, some of the more dramatic erosional and depositional marks on the landscape.
Staying within eight miles of the college and on the Lake Erie side of the nearby St. Lawrence - Mississippi continental divide, this trip will climb the hydraulic gradient of a glacial meltwater system that incised deep channels through Devonian bedrock, depositing sediment as deltaic gravels and lake clays.
We will begin at beaches of two of the large ancestral pro-glacial lakes of the Erie basin that are locally 170 feet and 240 feet, respectively, above the water level of present Lake Erie. The trip will ascend another 300 feet, then another 100 feet, as we follow a sub-marginal meltwater channel to the levels of two smaller lakes that were impounded along the ice margin.
Stops 1, 2, and 7, on the map below, will allow hands-on inspection of glacially derived gravels, and stop 6 will be in lake clay. The rest of the stops will be to view a channel that is now relatively dry, but would have been actively carrying meltwater during one or more glacial phases. The diagrams on the next two pages offer background on local glacial history and a schematic view of the subject channel.

SunG: PADDLING UP A MELTWATER CHANNEL: A LATE-WISCONSINAN ICE-MARGINAL CRUISE NEAR FREDONIA, NEW YORK

Passing over Canadaway Creek.
This valley formed embayments for proglacial Lake Whittlesey and Lakes Warren.

US Route 20 follows the Lake Warren strandline
US Route 20 follows the Lake Warren strandline from Central Ohio into Western New York. Gravel pits close to the highway provide an abundant source of aggregate for the highway.

View of the Escarpment to the left of the highway.
There are no resistant units to account for the formation of this cuesta. Abundant grape vineyards are growing in the well drained sands and gravels of Lakes Warren and Whittlesey beach deposits to the south.

A cemetery to the left.
There are many cemeteries located in the well drained deposits because they can be dug in almost year round.

STOP 1. Gravel Pit In Lakes Warren Beach Deposits.
This gravel pit displays typical deposits of a Lake Warren shoreline. U.S. Route 20 is constructed primarily of this material and follows the beach ridge for several hundred miles from northern Ohio to Batavia, New York. Lake Warren deposits are typically cross-bedded, well-washed sands and gravels. They were deposited within the high energy beach environment associated with each Lake Warren shoreline. The northward dipping beach face is well exposed on the western and eastern pit walls.
Lake Warren deposits differ from the corresponding Lake Whittlesey deposits which lie further to the south and about 70 feet higher in elevation on the lake plain (found along the ridge through Webster Road Cemetery on the map at left). Lake Warren deposits are generally finer grained and better washed than typical Lake Whittlesey deposits. This may have been a function of higher wave energy and/or a longer occupation of the Warren beach.
Notice the swallow nests bored into the firm silt deposits near the upper wall of the pit.
The beach of Lake Warren is the youngest glacial feature we will visit today, with Lake Whittlesey about 500 years older, and our subject meltwater channel (seen as Little Canadaway Creek on the map) older still.

Southern wall of an abandoned gravel pit.
To the south the apparent wave cut terrace just north of Webster Road is the southern wall of an abandoned gravel pit.

The Brocton Arch.
Prior to World War 2 several of the villages in Chautauqua County had similar arches in their villages. However, all of the villages but Brocton removed theirs to provide scrap metal for the war effort.

Webster road follows the Lake Whittlesey Strandline
Webster road follows the Lake Whittlesey Strandline for several miles from the Town of Portland east through the town of Pomfret.

STOP 2. Gravel Pit In Lake Whittlesey Beach Deposits.
This is one of two gravel pits near Portland that were recently opened for construction of a State prison in Brocton. While the elevation and nature of the gravel correspond to a Lake Whittlesey shoreline, the original deposition may have been into an earlier lake. Notice on the map that the 800-foot contour outlines a possible relic spit, formed by wave currents moving sediment easterly from the area near Cemetery Road at Webster Road.
The gravel here is widespread, forming a wide plateau between Webster Road and Ellicott Road. Much of the sediment is locally-derived, with large clasts of siltstone, apparently from Devonian strata higher in the escarpment to the south and east. The feature we are in has been recognized as a delta by Fairchild (1907), who considered that the sediment might be primarily rock excavated from the meltwater channel to the east and northeast. The southerly wall of this channel can be seen on the map as the ridge where Ellicott Road meets Highland Avenue.

To the north notice the fine surficial expression of the meltwater channel.

Notice the gas well just off to the north of Ellicott Road.
Gas wells are very common throughout Western NewYork. They are drilled primarily into the highly productive sandstones of the Silurian Medina Group which dip gently towards the southwest at approximately 50 ft/mi.

STOP 3. Overview Of The Meltwater Channel.
Stop 3 is an overview of channel morphology; envision a river of meltwater raging through the now-dry valley.

Passing through the channel
Passing through the channel towards the Lake Whittlesey strandline at Webster Road.

Webster road is still following the ancestral shoreline of Lake Whittlesey.

The southern wall of the abandoned gravel pit
The southern wall of the abandoned gravel pit mentioned previously within this roadlog is just left (north) of the road.

Passing over a buried channel indicated by seismic profiles and core samples.

Dropping into the channel
Dropping into the channel and passing over the misfit Little Canadaway Creek which currently occupies the meltwater channel.

Passing up the south wall of the meltwater channel.

STOP 4. A Walk Into The Ancestral Meltwater Channel
Plus A Visit To One Of Its "Hanging" Tributaries.
Stop 4 takes us to the channel's intersection with Chautauqua Road, where a drift-filled valley running northwesterly has been proposed in the area circled (Woodbury and Lash, 1985, abstract is inset on facing page). The natural gentle slope over the buried valley provided the least treacherous route for early settlers to cross the deep meltwater channel; Chautauqua Road is one of the county's oldest roads, commissioned by the Holland Land Company in the very early 1800s to connect Fredonia (then known as Canadaway) with the county seat in Mayville. At STOP 4 we will visit one of several 40-foot waterfalls that are characteristic of the streams running northerly into the relic channel. The waterfalls are recessed about 1000 feet southerly from the meltwater channel, apparently marking the extent of post-glacial headward erosion away from the "hanging" positions they would have had along the channel wall when the glacier melted away.
The swampy knob and kettle terrain to the south represents an end-moraine near the crest of Concord Drive.

STOP 5. Distant Inlet Channel And A Panoramic View Of Proglacial Lake Shumla.
This is the outlet col for pro-glacial Lake Shumla (Fairchild, 1907), formed as ice dammed the northerly flowing Canadaway Creek. The outlet elevation, controlling the lake surface, is 1105 feet. Visibility permitting, we will use a surveying instrument to view an inlet channel that brought a flood of meltwater into Lake Shumla; the inlet can be seen as a shallow topographic dent along the hilltop located about 3 miles to the northeast.
For a wider perspective of the outlet channel, fold the map on the preceding page into this page and match it to the map at right.
Also on the map, note the notch in the hillside northwest of our stop. This could have been an outlet for a lower level of Lake Shumla.

STOP 6. Ditch Exposure Of Laminated (Varved?) Clays With Dropstones
As Deposited Into Proglacial Lake Shumla.
We are 130 feet under the water surface of Lake Shumla where fine clay particles settled to the bottom. Some investigators have classified the clays as varved, interpreting the rhythmic laminations as seasonal variations in depositional environment. The roadway is "Old Route 60," while present Route 60 is located over the knoll to the east and is also cut through lake clays. The slump-prone sediments have been a problem for highway engineers for nearly 30 years, and we will drive through a clay cut that has yet to be worked into a stable angle of repose.
Lake Shumla was formed several times and at several water levels during the Pleistocene glacial oscillations, so the clays we see are not likely the result of just the most recent glaciation.

OPTIONAL STOP: Laminated clays which were deposited into Lake Shumla
This is an optional stop due to the safety constraints put on us by a large group. This is a fine exposure of laminated clays which were deposited into Lake Shumla. When NY Route 60 was initially cut through this area the engineers placed a 90 degree roadcut through this material. Over the following years the material slumped every time it was water laden until it reached the much stabler shallower exposure that appears today. As you climb up the exposure you will see beautiful clean clay littered with abundant dropstones.

STOP 7. Gravel Pit In The Deposits Of A Probable Delta Built Into Lake Shumla.
This gravel pit is near Lake Shumla's inlet. We appear to be in a delta deposited and worked by meltwater flowing from the channel and upper lake located northeast of here. Lake Shumla provided a quiet "sink" for sediments in the meltwater chain: the coarse-grain sediments settled at the delta, and the fine-grained clays deposited at mid-lake, while little or no sediment was carried by the meltwater just as it spilled out the channel to the southwest.

STOP 8. Spectacular View Of The Col Which Was The Outlet Of Proglacial Lake Shumla.
This stop presents a rather spectacular overview of the outlet channel of Lake Shumla. It appears as a dramatic V-notch in the hilltop about 2 miles to the west.
As you view the channel, mentally re-construct a mountain of slushy ice overhead, thickening northeasterly, toward Buffalo, and thinning to an end moraine gushing with meltwater within 2 miles to the south. We are about 150 feet above the lake, looking down on the 2.5 square-mile surface of frigid water. Can you spot any icebergs?

Proceeding down the south wall of the channel.

Passing through the bottom of the channel.

Passing up the north wall of the channel.

Passing down the north wall of the channel.

Passing up the south wall of the channel.

Proceeding up a long slope onto the Escarpment
Proceeding up a long slope onto the Escarpment which is the northern edge of the Allegheny Plateau.

Passing over an asymmetrical terrace above the south wall of the channel.

Passing over a terrace which is the crest of the southern wall of the channel.

STOP 9. Cross-Sectional View Of Channel And Terraces.
We have just driven through the meltwater channel and are parked near its northerly crest. Our route is depicted by the cross-section inset at left. Compare the section to your view looking southerly, down into and across the channel. Note the terraces on the southerly,wall, which were apparently cut by ice-marginal streams walled by the glacier on their northerly sides.
On the map, note the deep, dry channel easterly and southeasterly from our stop. This was the spillway for a pro-glacial lake, with a surface elevation of 1205 feet, that formed over the Forestville area as ice dammed the northerly flowing Walnut Creek. Our field trip ends here, so we'll save Lake Forestville and its inlets for a new day and a fresh paddle.
Before we depart, examine the brass disk set in concrete near the southwestern corner of the road intersection. It is a horizontal ground control station for the photogrammetrically-produced 7.5-minute-series topographic sheets. USGS designates it "IT 38 WX 1952," with position determined at 42°27'07.544" north latitude and 79°14'12.489" west longitude.

63rd Annual Meeting
James R. Ebert, Editor
College at Oneonta
Oneonta, New York 13820-4015
Published by the New York State Geological Association. Additional copies may be obtained from the permanent Executive Secretary, James F. Olmsted. Center for Earth and Environmental Science. State University of New York, College at Plattsburgh, Plattsburgh, New York 12901.
Cover: Kingfisher Tower, Otsego lake
PREFACE AND ACKNOWLEDGEMENTS
We are very pleased to welcome you to the 63rd Annual Meeting of the New York State Geological Association and to the State University of New York College at Oneonta. Seven of this year's trip leaders were also contributors in 1977, when this department last hosted NYSGA. In the intervening fourteen years, tremendous advances have been made in our understanding of the geology of central New York.
From precision geochronology of precambrian rocks to processes of deglaciation and interaction of glacial and karst processes, geological investigation in the heart of New York is alive and well. Since 1977, we have witnessed the burgeoning of "sequence stratigraphy", the emergence of hydrogeology as a distinct subdiscipline and the expansion of process-oriented sedimentology. These changes are clearly represented by the spectrum of field trips in this guidebook. Sequence stratigraphy is applied to Lower Devonian Limestones, Middle Devonian clastics, and Quaternary sediments in Finger Lakes' basins. Hydrological studies of caves and glacial sediments are described. Physical processes of sedimentation in Devonian shelf, shore, and fluvial environments are also examined. We hope that you enjoy the field trips and other activities this weekend and that you find them stimulating and enlightening.
The core of an NYSGA meeting is obviously the slate of field trips. The contributions of all the trip leaders (especially those that submitted manuscripts early!) are gratefully acknowledged. Without their efforts, the Association could not exist.
For all endeavors such as this, there is usually an unsung hero who is largely responsible for bringing the event to fruition. For typing the announcements, executing editorial changes, generally greasing the institutional wheels and reassuring a sometimes frazzled editor and frantic president, Moira Beach is our unsung hero.
We would also like to acknowledge the herculean efforts of Wayne Byam and his staff in the college print shop, Dorothy Gill for the cover layout, Bill Harman for supplying the sketch for the cover, Charlie Winters for shooting negatives for some figures and the administration of the college for their support and encouragement.
Finally, we thank the students of the Department of Earth Sciences, especially the Geology Club under the leadership of Heather Finlayson and Kelly Milunich for their logistical and clerical assistance.
James R. Ebert, President New York State Geological Association Department of Earth Sciences State University of New York College at Oneonta Oneonta, NY 13820-4015

SP1: SUBSURFACE GEOLOGY OF THE FINGER LAKES REGION
HENRY T. MULLINS, ROBERT W. WELLNER, JOHN L. PETRUCCIONE, EDWARD J. HINCHEY and STEVEN WANZER
Syracuse, New York 13244
The Finger Lakes of central New York State (Fig. 1) have long been recognized as the product of continental glaciation. In 1868 Louis Agassiz spoke of the "glacial heritage" of the region (Coates, 1968) and since then numerous glacial geomorphic investigations have been undertaken (Mullins et al., 1989). However, most previous studies dealt with surficial features and because of this relatively little was known about the subsurface Quaternary geology of these world renown lakes.
That the Finger Lakes are deeply scoured and infilled by thick sediment sequences was known from bathymetric surveys of the lakes completed in the late 1800's (Bloomfield, 1978), a drill record of 1,080' (329m) of unconsolidated sediment at Watkins Glen (Tarr, 1904), and the publication of a line drawing of one seismic reflection profile from Seneca Lake (Woodrow et al., 1969). This paucity of subsurface geologic data has been a major void in our knowledge and understanding of the geologic history of the Finger Lakes. Many questions remained unresolved including the most fundamental --"When and by what processes were the great Finger Lakes troughs eroded?" (Bloom, 1984, p. 61). Based on the one seismic reflection profile from Seneca Lake, Bloom (1984) noted that bedrock beneath the lake floor was more V-shaped like that of a river valley rather than the expected U-shaped glacial trough, and that there had been multiple erosional and depositional events. He concluded that more comprehensive seismic reflection surveys of the Finger Lakes "might reveal a barely suspected missing chapter in the history of the Finger Lakes region" (Bloom, 1984, p. 61).
During the summer of 1984 we initiated a seismic reflection investigation of the Finger Lakes with a pilot study of the northern half of Seneca Lake (Stephens, 1986) supported by a "starter" grant from Syracuse University. Preliminary results were very encouraging and revealed a detailed stratigraphy of a thick sediment fill. These preliminary data formed the basis of a National Science Foundation grant for a comprehensive seismic reflection study of all eleven Finger Lakes which was carried out during the summers of 1986 and 1987 (Mullins and Hinchey, 1989). The scientific objectives of this study were three-fold: (1) the provincial question of the origin and evolution of the Finger Lakes; (2) evaluation of the processes of deglaciation along the southern margin of the Laurentide ice sheet; and (3) to use the thick sediment sequence beneath the lakes as a record of continental environmental (paleolimnology/paleoclimatology) change.
In order to fully realize these scientific objectives it was also necessary to extend our lake-based seismic surveys to adjacent on-land areas and to "ground truth" these geophysical data with subsurface geologic samples. Phase II of our investigation was also supported by NSF, and on-land multi-channel seismic reflection profiles were obtained during the summers of 1988 and 1990. In July 1990 we also recovered a 120 m (400') drill core from the dry valley south of Canandaigua Lake, north of the village of Naples, N.Y. These new drill core samples, which are presently being dated and analyzed, complement 26 piston cores (up to 5 m long) collected from Seneca and Cayuga Lakes. Previous subsurface geologic information on Quaternary deposits beneath the Finger Lakes was limited to stratigraphic descriptions of water wells at Ithaca (Tarr, 1904) and short cores recovered from southern Cayuga Lake (Ludlam, 1967) and northern Seneca Lake (Woodrow et al., 1969).
The purpose of this field trip is to provide a new and unique perspective on the Quaternary geology of the Finger Lakes -- the shallow subsurface. Following a brief tour of surficial features, we will embark on a comprehensive overview of the subsurface Quaternary geology of the eastern Finger Lakes (Skaneateles, Owasco, Cayuga, Seneca, Keuka, and Canandaigua) as well as Tully Valley (a "dry Finger Lake") and Montezuma wetlands (a glacial meltwater system). We have planned 12 stops over a 1.5 day period to examine and discuss seismic reflection, gravity, and drill core data at acquisition sites. This non-traditional field trip has no outcrop stops so leave your shovels but bring your imagination!
SURFICIAL GEOLOGY
The surficial geology of the Finger Lakes region has recently been compiled by Muller and Cadwell (1986; Fig. 2). Much of the upland area in the Finger Lakes region is covered by relatively thin till. However, a series of low-relief, chevroned, recessional till moraines also occur on the uplands in the central and southern regions of the lakes. At the north end of the lakes, recessional till moraines become more continuous in an east-west direction (Fig. 2).
North of the Finger Lakes is an extensive field of drumlins and meltwater channels which extend to Lake Ontario. Glaciolacustrine and swamp deposits selectively infill north-south oriented channels whereas an east-west system of channels is largely filled by outwash.
South of the lakes, and confined to the valleys, are well-developed kame moraines, collectively known as the Valley Heads moraine. These moraines are not connected over the uplands and consist principally of water-laid stratified drift. Based on regional correlations, Fullerton (1986) suggests that the Valley Heads moraines were deposited between 12.95 and 14.1 ka. If correct, Valley Heads deposition correlates with a pulse of rapid melting of the Laurentide ice sheet centered at 13.5 ka as recognized in the oxygen isotope record of North Atlantic and Gulf of Mexico deep-sea sediments (Ruddiman, 1987). To the south of the Valley Heads is a well-developed, arcuate system of outwash-filled valleys that likely served as meltwater channels during deglaciation.
There are relatively few radiocarbon dates available from the Finger Lakes region. Many of those reported (summarized by Muller and Cadwell, 1986) are "dead" dates >35 ka suggesting pre-late Wisconsin glacial deposits. Based on these dates Bloom (1986) has suggested that the valleys around Ithaca, and presumably the other Finger Lakes valleys, were excavated "prior to two ice ages ago" (p. 263), well before the late Wisconsin.

SP1: SUBSURFACE GEOLOGY OF THE FINGER LAKES REGION

East margin of Onondaga Trough
Drive south along east margin of Onondaga Trough toward
Cortland.

Note jointed bedrock along off-ramp.

STOP 1. - dead end of Amidon Road - overview of Tully Valley.
This brief stop at the dead end of Amidon Road provides (weather permitting) an outstanding south-directed view of Tully Valley, a "dry" Finger Lake valley. Clearly visible are the steep glacially-eroded bedrock walls of the valley and its relatively flat, sediment-filled floor which produced an overall U-shape profile. To the south is the Valley Heads moraine at Tully which completely fills the valley but does not extend over adjacent upland divides. The primary purpose of this stop is to give you a view of a "Finger Lake" without the water!
During late Wisconsin deglaciation glacial meltwaters ponded in this valley to form a proglacial lake more than 183 m (600') deep (Hand and Muller, 1972). The valley floor has an elevation today of about 152 m (500') and Bare Mountain on the west side of the valley crests at about 457 m (1500') which means that the valley was filled to about 60% capacity by this preglacial lake or about to the level we are standing (351 m, 1150').
As the ice receded to the north up contiguous Onondaga Trough east-west outlets were progressively exposed and the preglacial meltwaters in Tully Valley began to drain into the Mohawk through the Syracuse meltwater channels (Hand and Muller, 1972). Hand (1978) suggests that the outflow of water from Tully Valley occurred in a series of catastrophic flood events which ultimately led to the "dry Finger Lake" valley we see today. Since the draining of Tully Valley some 12 ka ago, post-glacial alluvium has washed into the valley, with the large alluvial fan at the mouth of the Rattlesnake Gulf being the most prominent.
From the vantage point of this overview stop we will drive down into this "dry Finger Lake" to examine subsurface data from the floor of Tully Valley.

STOP 2: THE FLOOR OF TULLY VALLEY
At this stop along Otisco Road you are now standing at the bottom of what once was a Finger Lake as deep as modern day Seneca Lake. How far below the valley floor does bedrock extend? How thick are the sediments beneath the valley floor and what is their geologic nature? To address these simple
questions we have collected preliminary multichannel seismic reflection and gravity data which have been integrated with available drill hole information.
A gravity transect across Webster Road, 2.5 km north of our current location, suggests a total sediment fill of about 134 m (440') with bedrock eroded to within 30 m (100') of sea level. Sediment thickness of at least 117 m (385') has been confirmed there by a drill hole that did not reach bedrock.
A multichannel (6-fold) weight-drop seismic reflection profile shot across Otisco Road reveals a high-amplitude reflector interpreted as bedrock at a maximum of 0.13 sec. of two-way travel time. Calculation of true depth to bedrock is dependent upon the compressional wave velocity of overlying sediment. Based on wide-angle reflection experiments conducted in the Finger Lakes (Mullins and Hinchey, 1989) as well as seismic refraction data from southern Tully Valley (Faltyn, 1957) unconsolidated sediments beneath the Finger Lake valleys have a P-wave velocity in the range of 1.5-2.2 km/sec. Using this range of velocities, maximum subsurface depth to bedrock beneath Otisco Road is on the order of 98-130 m (321-4262'). If one accepts the higher range of velocities (2.0 km/sec.) there is good agreement between the seismic (130 m) and gravity (134 m) data. Both sets of data show a relatively flat bedrock floor beneath the axial portion of Tully Valley. Total bedrock erosion, as measured from the top of adjacent divides to bedrock beneath Tully Valley, has been on the order of 540 m (1770').
The seismic reflection data also suggest that there are three major stratigraphic sequences beneath Tully Valley (Fig. 5). The youngest sequence is characterized by discontinuous, high-frequency reflections and thickens to the west toward the alluvial fan at the mouth of Rattlesnake Gulf where it is as much as 60-80 m (197-262') thick. We interpret this sequence as post-glacial alluvial in-fill. The middle stratigraphic unit is largely "transparent" or reflection-free indicating massive sediment which we interpret as glacio-lacustrine muds, that are as much as 53-70 m (174-230') thick. The top of this middle unit is undulatory which may be a consequence of loading by the overlying alluvial fill. The lowermost stratigraphic sequence beneath Tully Valley is also transparent and is characterized by a discontinuous, high-amplitude reflection at its top. This oldest sequence is relatively thin (19-25 m; 62-82') and is interpreted as a coarse-grained facies.
Our inferences on depth to bedrock and stratigraphic nature of the sediment fill beneath Tully Valley based on geophysical data are supported by available drill hole data. Getchell (1983) reported the gross stratigraphy of nine drill holes located in the southern end of Tully Valley (Fig. 6). Eight of the nine wells penetrated three major stratigraphic units: (1) an upper gravel/clayey gravel unit up to 24m (80') thick; (2) a middle clay sequence 99-134 m (325-440') thick; and, (3) a basal gravel/sandy gravel unit at least 17 m (55') thick. The one well (WL-6) that did not penetrate the basal gravel unit reached shale bedrock at a subsurface depth of 142 m (465') which is at an elevation of 72 m (235') above sea level.
Combined, the subsurface geophysical and drill hole data reveal a deeply scoured trough beneath Tully Valley with bedrock rising to the south, which is consistent with reflection data from the Finger Lakes (Mullins and Hinchey, 1989). The data also indicate a relatively simple infill stratigraphy of washed subglacial (?) sands and gravel at the base overlain by glacio-lacustrine muds which in turn are capped by coarse-grained alluvial gravels and clayey gravels. Although there is no chronostratigraphic control available, the gross lithostratigraphy beneath Tully Valley argues for a single overall infill sequence.
As we leave Otisco Road we will drive south along Tully Valley and then up the Valley Heads moraine which crests at an elevation of about 366 m (1200') which is some 213 m (700') above the floor of the adjacent valley. Gravel pit exposures here reveal washed sands and gravel that are crudely stratified. The Valley Heads deposits argue for an extended ice marginal environment here with large volumes of coarse-grained debris, both local and exotic, pumped through Tully Valley about 13-14 ka. The thickness of sediment beneath the Valley Heads moraine at Tully and the adjacent outwash plain has yet to be resolved, but is certainly an important question. Durham (1958) suggested that the position of the Valley Heads moraine was controlled by a pre-glacial drainage divide based on a well record at Little York which encountered bedrock at a subsurface depth of only 67 m (220'). However, it is not known whether or not this well, at an elevation of 354 m (1160'), was located along the valley axis. Preliminary gravity data obtained along Little York Road by Steve Wanzer, suggest that bedrock may be considerably deeper than that suggested by Durham (1958). This topic will be part of Steve's master's thesis, and hopefully he will have more definitive results by the time of our field trip.
From the Valley Heads moraine at Tully we will head northwest and drive around the north end of Otisco Lake (the easternmost Finger Lake), and then south to our next stop at the south end of Skaneateles Lake. When leaving the Valley Heads we will be able to see its contact with the bedrock wall of Tully Valley and observe that the moraine does not extend up and over the divide. At the northeast corner of Otisco Lake we will also pass by a hanging delta at Amber some 61 m (200') above the modern lake level of Otisco Lake, attesting to higher glacial lake levels.
Otisco Lake today is relatively shallow (maximum depth of 21 m or 69') and eutrophic which greatly limited our ability to collect seismic reflection data due to gas-saturated sediment (Hinchey, 1986). However, "windows" of seismic data indicate at least 83 m of sediment beneath Otisco Lake (Hinchey, 1986). As we drive around the north end of Otisco Lake we will (weather permitting) have an excellent view down the axis of the lake and Otisco Valley. The steep, U-shaped valley wall on the west side of the valley has a slope of about 35°. From Otisco Lake we will drive over the divide to Skaneateles Lake. Bedrock outcrops along the road attest to the relative paucity of glacial erosion and deposition on the uplands compared to the adjacent valleys.

Contact between Valley Heads moraine and bedrock
Note contact between Valley Heads moraine and bedrock of valley wall as you head west.

Amber hanging delta

STOP 3: SOUTH END OF SKANEATELES LAKE
This stop, high above the lake at the Onondaga-Cortland county line, provides a spectacular north-view of one of the most scenic Finger Lakes -- Skaneateles. We are standing at an elevation of 506 m (1660') which is slightly lower than the surrounding top of the plateau at about 579 m (1900'), but well above lake level which is at 263m (863'). As you look to the north, it is quite apparent that the southern end of Skaneateles Lake is much more deeply incised than it is to the north. Also visible are three "points" along the west shore of the lake which represent post-glacial stream deltas that have built into Skaneateles Lake as higher glacial lake levels receded. The overall morphology of the Skaneateles Lake basin is similar to that observed in Tully Valley except that the valley is partially filled with water.
Maximum water depth in Skaneateles Lake is 90 m (295') which occurs at about the north-south midpoint of the lake. Seismic reflection data indicate that bedrock is relatively shallow beneath the north end of the lake but deepens toward the central portion of the lake where maximum erosion down to about sea level has produced a closed rock basin. Bedrock gradually rises toward the south end of the lake producing an overall spoon-shaped longitudinal profile which is typical of the Finger Lakes (Mullins and Hinchey, 1989). Crossing lines indicate broad, U-shaped bedrock profiles at the north end of the lake which become progressively more incised and V-shaped toward the south, which is also typical of the Finger Lakes (Mullins and Hinchey, 1989). Total erosion of bedrock, from the top of the plateau to the maximum extent of bedrock beneath the lake, has been on the order of 580 m (1900').
Maximum sediment thickness beneath Skaneateles Lake is on the order of 170 m (Mullins and Hinchey, 1989) with most of the sediment in the southern half of the lake basin. The most regionally significant feature of the stratigraphy beneath Skaneateles is onlap at the south end of the lake of transparent to highly reflective sediments onto a southward thickening wedge characterized by a hummocky chaotic seismic facies. The younger package of sediment is interpreted as largely northerly-derived glacio-lacustrine deposits. The older chaotic wedge that thickens to the south, projects to on-land outcrops of Valley Heads. If Fullerton's (1986) correlation of Valley Heads at 13-14 ka is correct, this onlap at the south end of Skaneateles Lake implies that the sediment fill beneath the lake is all less than 14 ka, or of late Wisconsin to Holocene age. If older glacial sequences were deposited in Skaneateles valley they have been effectively removed by late Wisconsin glaciation.
Using this onlap relationship (14 ka) and a maximum sediment thickness of 170 m for Skaneateles Lake, we calculate an average rate of sediment accumulation of 12.1 m/1000 years. However, drilling south of Canandaigua Lake (see Stop #10) suggests that the post-glacial section is quite thin relative to the total thickness of sediment-fill which is consistent with our seismic stratigraphic interpretations. If 90% of the sediment fill beneath Skaneateles Lake was deposited over a 2 ka period between 12 and 14 ka, accumulation rates may have been as high as 77 m/1000 years. If correct, these calculations suggest that large volumes of sediment were rapidly deposited in the Skaneateles Lake basin during deglaciation.
A second stratigraphic feature of significance occurs at about the north-south midpoint of Skaneateles Lake. Here, a series of stacked, transparent wedges, each up to 15 m thick, occur. These wedges pinch-out to the south over a horizontal distance of 3-4 km and are interbedded with highly reflective units interpreted as glacio-lacustrine deposits. Longitudinal (N-S) profiles indicate irregular tops with large diffractions. The seismically transparent (reflection-free) nature of these wedges indicates that they consist of massive sediment.
One interpretation is that these wedges represent "inflow events" deposited rapidly, issuing perhaps from a subglacial conduit; in essence a rapid pulse of massive debris. An alternative interpretation is that these wedges represent "till-tongues" similar to those described by King et al. (1991). Unfortunately, no samples from the wedges are available to resolve which (if either) interpretation is correct. However, Ed Hinchey promises to be on hand during the field trip to defend our view that these wedges represent sudden inflow events.
Regardless of the interpretation of these wedges, they suggest the presence of an ice margin that was either grounded or pinned here, where there is a break in the bedrock slope. North of these wedges total sediment thickness thins appreciably, consisting of a thin, highly-reflective (glacio-lacustrine?) unit overlying a thin, chaotic (subglacial?) sequence. These stratigraphic relationships suggest that the ice margin in Skaneateles valley retreated rapidly (by calving?) to the north from its Valley Heads position to the lake's midpoint where it stabilized and issued large volumes of sediment into a proglacial lake.
From our overview of Skaneateles Lake we will drive down into the valley and around the south end of the lake. This will give you a good opportunity to get a "feel" for how deeply (and steeply) incised the south end of Skaneateles Lake is into bedrock of the surrounding Appalachian Plateau. As we cross the valley floor at the south end of Skaneateles Lake keep in mind that bedrock extends about 150 m (~500') beneath the surface. We will then drive up the west wall of Skaneateles Lake, over the divide to Owasco valley and through the village of Moravia to our next stop overlooking Owasco Lake at Ensnare.

Note bedrock outcrops along west valley wall

STOP 4: OWASCO LAKE
This stop near the intersection of Ensnore Road and State Route 38 provides a good north-oriented overview of Owasco Lake. Elevation here is 323 m (1058') which is about half way between lake level at 217 m (711') and the crest of the upland divide at 402 m (1320') just to our west.
Maximum water depth beneath Owasco Lake is 52 m (170'). Like the other Finger Lakes, it has steep walls and a relatively flat floor. Bedrock beneath the lake extends down to an elevation of ~80 m (262') above sea-level. Total erosion, from the top of the divide here at Ensnare to the bottom of bedrock beneath the lake, has been on the order of 320 m (1050').
Total sediment thickness beneath Owasco Lake is on the order of 100 m (328'). The stratigraphy beneath the lake is particularly well-defined by our seismic reflection data. A basal, seismically chaotic sequence which thickens to the south, is overlain by a highly reflective unit. We infer a single coarse-grained, subglacial sequence overlain by proglacial and post-glacial lacustrine deposits.
In the northern third of Owasco Lake, an axial ridge is buried beneath the highly reflective lacustrine sequence. This ridge, with up to 20 m (66') of relief, is sinuous and can be traced over a lateral distance of at least 5 km. We interpret this buried ridge as an esker which implies the past presence of a large subglacial meltwater conduit along the axis of northern Owasco Lake. Such an ice tunnel may have been responsible for the supply of coarse subglacial debris to the basal chaotic sequence beneath Owasco.
Another significant stratigraphic feature of the sediment-fill beneath Owasco Lake is a remarkably transparent (reflection-free) wedge of sediment in the northern half of the basin. The transparent nature of this deposit indicates massive sediment which is interbedded with highly reflective glacio-lacustrine sequences. Underlying units reveal only slight erosion and the top of this transparent unit is smooth. The wedge is up to 15 m (50') thick in the north and pinches out to zero thickness near the north-south midpoint of the lake. Transverse reflection profiles indicate that the wedge onlaps both the east and west bedrock walls of the lake. Although no subsurface samples are available, we interpret this transparent wedge as a subaqueous outwash fan of massive sand or silt, perhaps analogous to the deposits described by Rust and Romanelli (1973) near Ottawa. If this wedge represents in essence an "inflow event," it further argues in favor of the role of subglacial meltwater in the transport of debris to the southern margin of the Laurentide Ice Sheet, similar to the suggestion by Gustavson and Boothroyd (1987).
From our overlook of Owasco Lake we will head west over the divide toward Cayuga Lake. Just prior to entering the village of Poplar Ridge, we will cross one of the "chevron" till moraines mapped by Muller and Cadwell (1986). Radiocarbon analysis of wood overlying the south end of this till moraine yielded a date of 11,410 ±410 years (Muller and Cadwell, 1986).

Cross "chevron moraine" just east of Poplar Ridge.

STOP 5: CAYUGA LAKE
This stop is located at Long Point State Park at about the midpoint (east shore) of Cayuga Lake, just south of the village of Aurora. Cayuga Lake is one of the two largest Finger Lakes extending north-south for a distance of about 60 km with a maximum width of about 5 km. It has a maximum water depth of 132 m (433') located about two-thirds of the length of the lake form its north end. At this point of maximum water depth, the lake bottom is 15 m (51') below sea-level. Off Long Point maximum water depth is 100m (361'). Lake level is at 116 m (382') which is the lowest elevation of all the Finger Lakes.
We have collected more than 150 km of high-resolution uniboom seismic reflection data from Cayuga Lake which have been correlated with 11 piston cores. Bedrock beneath Cayuga Lake has been eroded as much as 358 m (1174') below lake level, which means that bedrock extends as much as 242 m (794') below sea-level!
A north-south schematic illustrates the overall "spoon-shaped" longitudinal profile of Cayuga Lake. Note that the maximum extent of erosion extends down to the Onondaga Limestone and appears to follow its southward dip before rising up through Hamilton Group shales at the south end of the lake. East-west schematics illustrate the broad, shallow form of the bedrock basin at the north end of the lake which becomes more narrow, and deeply incised to the south.
Maximum sediment fill beneath Cayuga Lake is 226 m (741') which occurs in the southern half of the lake basin. We have divided this fill into six seismically-defined depositional sequences: (I) The oldest sequence occurs only in the axial southern half of the lake basin where it is as much as 100 m (328') thick. This unit is characterized by a chaotic seismic facies and an irregular, hummocky upper surface which projects to Valley Heads outcrops south of the lake; (II) Sequence II is present throughout the lake basin and is up to 135 m (443') thick. It is characterized by a distinct north to south change in acoustic facies from chaotic to transparent. A piston core (#10) located at the crest of an esker-like ridge along the top of sequence II (Fig. 18) recovered less than a meter of fine-grained rhythmites with dropstones before bottoming in clast-supported gravels (Fig. 20); (III) This sequence occurs throughout the lake basin as a transparent (reflection-free) unit up to 59 m (194') thick. At the north end of the lake this sequence is diapiric where it intrudes vertically up to 20 m (66'). Although unsampled, the massive, diapiric nature of this sequence suggests rapidly deposited muds; (IV) Sequence IV is a package of high-frequency, parallel reflections in which individual reflectors can be traced for 10's km along the length of the lake basin. It has a rather uniform thickness of about 30 m (98') except at the north end where it is more than 60 m (197') thick. Piston cores from lake floor outcrops of this sequence, recovered fine-grained, centimeter-scale rhythmites with occasional dropstones that were deposited in a preglacial lake; (V) This sequence records a "turning point" in the history of Cayuga Lake. It is thickest (>30 m; 98') at the south end of the lake basin as well as off major "points" such as Myers Point and Sheldrake Point; and, it is not present at the north end of the lake. This sequence heralds the beginning of northward drainage and lateral sediment input to Cayuga Lake that likely accompanied the lowering of preglacial lake levels and erosion of regional, upland gorges as ice withdrew from Cayuga Valley (Fairchild, 1934a); (VI) Sequence VI is a low-amplitude to transparent seismic unit that is variable in thickness (8-19 m; 26-62') throughout the lake basin. Piston cores have recovered fine-grained organic-rich sediments from this sequence, some of which are "banded" and were perhaps deposited by turbidity currents (Ludlam, 1967).
After lunch at Long Point State Park we will head south to Buttermilk Falls State Park near the south end of Cayuga Lake at Ithaca.

STOP 6: SOUTH END OF CAYUGA LAKE
The purpose of this stop at scenic Buttermilk Falls State Park is to examine and discuss land-based, seismic reflection data (acquired from Cayuga valley across from the Park) that have been integrated with results from 13 wells reported by Tarr (1904). The bedrock reflection extends as much as 0.19 sec. of two-way travel time beneath the valley (Fig. 21). Using a range of interval velocities from 1.5 to 2.0 km/sec., maximum depth to bedrock here is 143 m (467') to 190 m (623'). Tarr (1904) reported a salt well along the western margin of Cayuga valley at Ithaca, that encountered bedrock at 131 m which provides a minimum value for depth to bedrock because of its western location. Maximum sediment thickness beneath Ithaca is probably on the order of 166 m (545').
Our land-based seismic reflection profile (which is of lower resolution than our lake data) also reveals four major stratigraphic units beneath the valley: (l) an upper transparent (reflection-free) unit up to 20 m (66') thick (assuming an interval velocity of 1.5 km/sec.); (2) a high-frequency unit about 19 m (62') thick; (3) a sequence, bound by high-amplitude reflections, up to 28 m (92') thick (assuming a velocity of 1.6 km/sec.), and, (4) a basal unit characterized by discontinuous high-amplitude reflections up to 85 m (279') thick (assuming a velocity of 1.7 km/sec.).
The stratigraphy of Tarr's (1904) 13 wells, all located along the western margin of the valley, is schematically illustrated in Figure 22. The upper layer in these wells is predominantly fine-grained massive clay (up to 18 m or 60' thick) with fragments of mollusks, plants, and wood, including logs. Beneath these organic-rich clays is a series of sand and gravel layers 6-21 m (20-70') thick. According to Tarr (1904), the sands are well-washed and the gravels well-rounded. Plant fragments, mollusks and logs also occur in these coarser beds.
In all wells, these coarser deposits are underlain by "a great thickness of clay" devoid of mollusk fragments (Tarr, 1904). There are also minor coarser units within this clay layer including scratched, angular pebbles. The base of this clay layer is irregular, occurring at subsurface depths between 61 m (200') and 85 m (280') in the 13 wells (Tarr, 1904).
Beneath this clay layer is a heterogenous, coarse-grained unit from which artesian water flowed (up to 300,000 gallons/day!) in many of the wells. The total thickness of this basal coarse-grained unit is not known as 11 of the 13 wells bottomed in it. Tarr (1904) describes this coarse basal unit as consisting of variable sediment ranging from washed sand and gravel, to till, to "quicksand."
Tarr (1904) interpreted all these subsurface sequences as late Wisconsinian --"Neither here nor in the other well that reached rock, nor, in fact, in any of the wells, was any older drift encountered. All the materials are such as might have been brought by the last ice advance, or deposited since the ice-sheet melted away." His view of the heterogenous basal coarse layer was that it is morainic; a subsurface extension of the nearby Valley Heads. We concur with Tarr's interpretation and our seismic data suggest that this basal Valley Heads facies extends to bedrock and is more than 100 m (328') thick. We correlate this unit with seismic sequence I beneath Cayuga Lake.
The middle clay layer with scratched angular stones, is interpreted by both Tarr and us as a proglacial lacustrine sequence, perhaps with dropstones which would suggest the presence of icebergs. We correlate this preglacial clay layer with seismic sequence IV beneath the lake. The overlying washed sands and gravels appear to be a fluvial/alluvial or shallow lacustrine facies, that likely records a drop in lake level and drainage reversal as ice receded from the north end of Cayuga Lake (seismic sequence V; Mullins and Hinchey, 1989). The succeeding organic-rich clays at the top of the section are likely a post-glacial lacustrine facies that records the flooding of the south end of Cayuga valley in response to differential isostatic rebound at the north end of the lake (Tarr, 1904). Since this flooding event, only a thin (8-12 m; 26-39') unit of organic-rich muds has accumulated in Cayuga Lake (seismic sequence VI).
Based on these correlations between our lacustrine seismic reflection data, land-based profile, and Tarr's well data, we have been able to "ground-truth" four of the six seismic stratigraphic sequences beneath Cayuga Lake (sequences I, IV, V, and VI). Sequences II and III pinch-out at the south end of Cayuga Lake and do not extend to Tarr's wells.
From Ithaca we will head west across the upland divide to Watkins Glen at the south end of Seneca Lake.

Note kame deposits in quarry across road.

STOP 7: SENECA LAKE
This stop at Warren Clute Memorial (Lakeside) Park near the south end of Seneca Lake is designed to examine both our lake-based and land-based seismic reflection data coupled with available drill hole data. Seneca Lake is the deepest of all the Finger Lakes having a maximum water depth of 186 m (610') (in the southern half of the lake) which is 50 m (165') below sea level.
The overall bedrock morphology beneath Seneca Lake is similar to the other Finger Lakes: spoon-shaped and deepening to the south in longitudinal (N-S) profile; and, in transverse profile (E-W), broad and shallow in the north becoming more deeply incised to the south (Mullins and Hinchey, 1989). Bedrock extends as much as 434 m (1423') below lake level which is 298 m (978') below sea level! This maximum depth of bedrock erosion occurs about one-third of the distance to the north end of the lake from Watkins Glen. It is only slightly deeper than the 257 m (842') depth below sea level predicted by Fairchild (1934b).
Thickness of the sediment-fill beneath Seneca Lake increases from north to south where it reaches a maximum of 270 m (886'). Seismic stratigraphic sequences beneath Seneca Lake are similar to those beneath Cayuga Lake except that there is a thicker transparent unit (sequence III). However, stratigraphic sequences could not be traced completely to the south end of the lake due to a highly irregular lake floor near the south end.
Similar to Owasco Lake an apparent esker is buried in the subsurface beneath Seneca Lake. A ridge, with up to 35 m (115') of relief, occurs at the base of the axial thalweg of northern Seneca Lake. This ridge can be traced from line to line for several kilometers. We interpret this sinuous ridge as an esker which, if correct, further implies the presence of sub-glacial meltwater conduits during early stages of erosion and infill of the Finger Lakes.
A "half-valley" (east side) multichannel profile collected on-land between Watkins Glen and Montour Falls, further documents large scale erosion and thick sediment fill beneath Seneca valley. The bedrock reflection here is quite distinct and extends at least 0.28 seconds of two-way travel time into the subsurface. Again, using a range of P-wave velocities of 1.5 - 2.0 km/sec., bedrock extends as much as 210-280 m (689-918') beneath the valley floor. The higher end of these possibilities is very compatible with a well drilled at the power station at the south end of Seneca Lake (just to the west of our stop at Lakeside Park) which reached bedrock at 281 m (922') (Wendy McPherson, USGS Ithaca, personal communication, 1991). Thus, bedrock at the south end of Seneca Lake extends only about 145m (476') below sea level compared to 298 m (978') below sea level further north, indicating that bedrock is rising to the south.
Our on-land profile reveals four major stratigraphic units above bedrock: (1) an upper transparent sequence about 20 m (66') thick; (2) a unit characterized by high-frequency reflections about 23 m (76') thick; (3) a largely transparent sequence with discontinuous high-amplitude reflections about 81 m (265') thick; and, (4) a basal, seismically chaotic high-amplitude sequence that is about 108 m (354') thick. By analogy with Tarr's (1904) well data from Ithaca as well as our own drill records south of Canandaigua Lake (stop #10) we interpret the basal chaotic sequence as Valley Heads equivalent; the overlying transparent unit as preglacial lake clays; the overlying high-frequency unit as fluvial/alluvial sands and gravels deposited as glacial lake levels dropped; and, the upper transparent unit as post-glacial lake muds deposited when the south end of the valley was flooded by isostatic rebound to the north. Again, it is our interpretation that there is only a single large infill sequence beneath the Finger Lakes.
From Watkins Glen we will head south to Horseheads passing through one of the largest Valley Heads deposits in the Finger Lakes region. Outcrops indicate that the Valley Heads here consist of water-laid, stratified sands and gravel. Near Horseheads the hummocky topography of the Valley Heads will give way to a more smooth outwash plain. From Horseheads we will drive west-northwest through Corning and then on to Bath where we will spend the evening. If it is still light, this drive will take us along a broad continuous valley along the Southern Tier Expressway which likely served as a channel for meltwater flow from the western Finger Lakes into the Susquehanna drainage system.

Note infilled lake valley to left as you head south from Watkins Glen.

Drive will take you along proglacial meltwater channel.

Drive will take you across Valley Heads and down to dry lake floor.

STOP 8: KEUKA LAKE (DAY TWO)
From our overnight stay in Bath, N.Y. we will head north to Hammondsport and then up along the west shore of Keuka Lake to our next stop at the north end of the west branch of Keuka Lake. Bath is located on an outwash plain just south of Valley Heads fill. Soon after leaving Bath you will be able to see hummocky terrain typical of the Valley Heads. We will then drop down to the dry lake floor on which the village of Hammondsport is located.
Keuka Lake is an anomalous Finger Lake in many regards. Most obvious is its two branches that converge to the south at Bluff Point which strongly suggests a southward directed, preglacial drainage system. Second, there are a number of circular to elliptical closed bathymetric depressions on the floor of both branches of Keuka Lake. Third, there is little north-south variation in the depth to bedrock beneath the northwest branch of the lake. And, fourth, Keuka Lake valley is the only non-through valley of the Finger Lakes.
Maximum water depth beneath Keuka Lake is 58 m (190') which occurs in a closed depression near the junction of the Lake's two branches. Bedrock has been eroded as much as 200 m (656') below lake level which is 18 m (59') above sea level. Total sediment thickness is rather uniform beneath the west branch with a maximum of about 160 m (525').
Our axial (longitudinal, N-S) reflection profiles clearly define the east branch of Keuka Lake as a hanging tributary valley to the west branch. Depth to bedrock beneath the east branch is significantly shallower and there is a distinct bedrock high or "sill" where the east branch joins the more deeply scoured west branch.
Axial profiles from the northwest branch of Keuka Lake indicate that the closed bathymetric depressions on the lake floor are remnants of ice-melt-out features. Reflectors beneath these depressions are displaced downwards suggesting post-depositional collapse and chaotic patterns suggest mass wasting. These melt-out features may be analogous to "dead-ice sinks" described by Fleisher (1986) who noticed that they occur preferentially in non-through valleys. He suggested that stagnant ice conditions develop in non-through valleys because of glacial thinning and detachment at headward divides which are not present in through valleys (Fleisher, 1986). The discovery of ice-melt-out features beneath Keuka Lake suggests a component of down-wasting here during deglaciation unlike the other Finger Lakes where ice retreat appears to have been more rapid, perhaps by calving.
Despite this evidence for down-wasting, the seismic stratigraphy beneath Keuka Lake at its southern end is typical of the other Finger Lakes (Fig. 28). A lower chaotic unit (sequence II) is overlain by a very transparent (reflection-free) sequence (III) which in turn is overlain by a highly reflective unit (IV) derived from the north. Sequence V, which is also highly reflective, thickens to the south and contains southerly-derived mass-movement deposits; and, sequence VI is a relatively low-amplitude facies that probably represents contemporary (post-glacial) lacustrine sedimentation.
From our overlook of the northwest branch of Keuka Lake we will drive west through Italy Valley to the village of Naples passing over Valley Heads fill and then to the south end of Canandaigua Lake.

There will be a brief stop to overlook drill site along Parrish Flat Road in valley.

STOP 9: CANANDAIGUA LAKE
This overlook stop provides a spectacular north-view of Canandaigua Lake -- "the chosen place." Bathymetric data reveal a symmetrical "tub-shaped" lake basin with a maximum water depth of 84 m (276') near its north-south midpoint. Bedrock has been eroded as much as 261 m (856') below lake level which is 51 m (168') below sea-level. Total erosion, from the top of the adjacent divides to the top bedrock beneath the lake, has been on the order of 630 m (2068'). An on-land seismic reflection profile across Valley Heads along Eel Pot Road south of Naples, suggests that although bedrock does rise to the south there may be as much as 250 m (820') of Valley Heads fill.
Maximum sediment thickness beneath Canandaigua Lake is 202m (663') which occurs in the southern half of the lake basin. Similar to the other Finger Lakes we recognize six seismically-defined depositional sequences beneath Canandaigua Lake; however, there are some significant differences. Most notable is sequence III --a transparent (reflection-free) facies --which on our axial line occupies a restricted, "scooped-out" depression near the center of the lake. These massive fine-grained (?) sediments are up to 60 m (197') thick, and are overlain by highly reflective sequences which onlap bedrock valley walls.
Another difference is that collectively, sequences IV-VI (highly reflective facies) thicken to the south implying a largely southerly derived source for these deposits. We have noticed a similar relationship in other Finger Lakes only for sequences V and VI which we have related to a lowering of glacial lake levels and a drainage reversal which accompanied complete ice withdrawal from the Finger Lake valleys. In the case of Canandaigua Lake, these data suggest that sediment input from the south end of the lake began sooner than in the other lakes. This may have been due to the fact that there are multiple valleys, which may have been ice-free at the time, that drain into the south end of Canandaigua Lake.
All seismic stratigraphic sequences beneath Canandaigua Lake, with the exception of sequence III, can be traced to the south end of the lake. These sequences do not pinch out here but appear to continue beneath the wetland and dry lake valley to the south. In fact, this is why we decided to locate our drill core to the south Canandaigua Lake. Figure 29 schematically illustrates the projection of seismic stratigraphic sequences beneath Canandaigua Lake to our drill site ~3 km to the south along Parrish Flat Road.

STOP 10: PARRISH FLAT ROAD (DRILL CORE RESULTS)
Parrish Flat Road, which cuts across the dry valley just south of Canandaigua Lake, provides a unique accessible location to correlate (as directly as possible) our lake-based seismic reflection data with drill core samples. Between the drill site and Canandaigua Lake (3 km to the north) are the High Tor wetlands; directly to the east is a large alluvial fan at the mouth of Conklin Gully; and 3 km to the south, Valley Heads deposits begin to crop out near the village of Naples.
A multichannel reflection profile collected along Parrish Flat Road in 1988 indicated that bedrock extends as much as 0.22 seconds of two-way travel time beneath the valley floor. Using an interval velocity of 1.5 km/sec., there is about 165 m (540') of sediment fill above bedrock here. This profile also suggested the presence of four stratigraphic units: (1) a thin, upper transparent unit about 11 m (37') thick, underlain by (2) a thin (~10 m, 33' thick) high frequency sequence that thickens to east toward the alluvial fan; (3) a thick (~94 m, 308') unit with discontinuous high-amplitude reflections; and, (4) a basal unit, about 50 m (165') thick, beneath an irregular, high-amplitude reflector.
Drill core samples were recovered in July 1990 at two sites along Parrish Flat Road: site 1 extended 120 m (400') into the subsurface; and site 2, located 168 m (550') to the west, extended only 12 m (40') into the subsurface. Although composite core recovery was only ~40%, vertical stratigraphic continuity was extended with the use of downhole geophysical (gamma ray and resistivity) logs. Data from a vertical seismic profile shot at the deeper drill hole indicate that P-wave velocities in the upper 100 m (328') of section are all less than 1.6 km/sec. indicating under-compacted materials.
Based on physical stratigraphy, we recognize five distinct stratigraphic sequences in the Canandaigua drill core: (1) an upper unit (12 m, 39' thick) of cyclic sequences of peat and lake clays; (2) a coarsening-upward, washed sand and gravel unit (containing artesian water) that is 14 m (46') thick; (3) a rhythmically bedded silt and sand sequence plus interbeds of massive clay with dropstones that is 60 m (197') thick; (4) a massive clay unit devoid of dropstones that is 23 m (75') thick; and (5) and basal coarse sand and gravel unit that would not support open-hole drilling. Although bedrock was not reached in this drill core, a gas well located in the center of the valley about 3 km to the south, did encounter bedrock at a subsurface depth of 143 m (470'). The age of these deposits has not yet been determined; however, ten peat samples from the upper 12 m (39') have been sent off for radiocarbon analysis and one sample of massive clay from 109 m (358') has been sent off for thermoluminescence dating. Hopefully results will be in hand by the time of the field trip.
Our stratigraphic results front the Canandaigua drill core are strikingly similar to those reported by Tarr (1904) from Ithaca (Cayuga Lake) as well as available drill core data from Tully Valley. Basically, a basal sand and gravel unit is overlain by a thick sequence of fine-grained, organic-poor sediment which in turn is capped by sands and gravels that grade up into organic-rich lake clays. We interpret this stratigraphy as a single infill sequence resulting from the last glaciation. The basal sands and gravels are interpreted as part of the Valley Heads fill (13-14 ka); the thick, organic-lean clay sequence is interpreted as glacio-lacustrine facies; the upper sands and gravels as prograding alluvial valley fill that formed as glacial lake levels dropped; and, the uppermost organic-rich sequence as post-glacial swamp and lacustrine deposits. The cyclic nature of these youngest sequences suggest that lake levels have fluctuated periodically in Canandaigua Lake, and perhaps the other Finger Lakes, during postglacial time. Much more detailed study of these upper cyclic sequences is currently underway as part of Rob Wellner's doctoral dissertation.
From Parrish Flat Road we will drive north along the western margin of Canandaigua Lake to the city of Canandaigua. Toward the north end of the lake you will begin to notice drumlins which will be very common as we drive east along the New York State Thruway to our next stop at Montezuma wetlands north of Cayuga Lake.

Look to right (east) across Montezuma channel.

STOP 11: MONTEZUMA CHANNELS
Montezuma National Wildlife Refuge is one of the largest freshwater wetlands in New York State. The wetlands actually occupy a southward directed, dendritic system of channels that funnel into the north end of Cayuga Lake, which has the lowest lake level (116 m, 382'). That these channels are relict, is evidenced by the fact that modern outlet drainage from Cayuga Lake is to the north.
The Montezuma channel system is unusually broad (up to 5 km) for having a north-south length of only ~25 km. The channels are quite distinct on satellite images of the Finger Lakes and have been mapped largely as swamp deposits by Muller and Cadwell (1986). The channels occur within a very well developed drumlin field but are neither drumlinized nor do they appear to truncate drumlins. The geologic significance of the Montezuma channels has been largely overlooked in previous regional analysis.
In order to better understand the subsurface geology of the Montezuma channels, we have collected about 12 km of on-land, multichannel seismic reflection profiles that have been integrated with available well data. A profile acquired at our stop along Armitage Road reveals a thalweg along the western edge of this eastern branch of the channel system. Bedrock here extends as much as 40 m (131') beneath the surface of the channel or 78 m (257') above sea level. Maximum depth to bedrock beneath the channels, based on well records, is 55 m (180').
Two well records are available from Armitage Road. One well along the eastern margin of the channel penetrated about 30 m (98') of clay on top of shale before bottoming in limestone at 38 m (125'). The second well, located in the channel's thalweg, bottomed in sand without reaching bedrock. Facies analysis of our reflection data suggest that the sands are restricted to the channel's thalweg.
The postglacial pollen record of the Montezuma channels has been investigated via a 12 m core recovered from Crusoe Lake located about 8 km north of Armitage Road (Cox and Lewis, 1965). This core retrieved about 6 m (20') of organic-rich gytta overlying 5 m (16') of clay (Fig. 36). Two radiocarbon dates from 5.0 m (16') and 1.3 m (4') below the lake floor yielded ages of 6,850 ±150 and 3,200 ±100 years, respectively (Cox and Lewis, 1965). Pollen data indicate that a spruce-pine-fir forest dominated the region prior to 6,850 years ago. The first deciduous forests (dominated by hemlock and oak) developed about 6,500 years ago during a time when the climate here may have been warmer and more moist than today (Cox and Lewis, 1965). Between about 3,000 and 2,000 years ago, beech replaced much of the hemlock suggesting a decrease in available moisture. During the past 2,000 years, the pollen record suggests a decrease in temperature and an increase of available moisture (Cox and Lewis, 1965). These authors also suggest that a large lake, of which Crusoe is a remnant, may have persisted in Montezuma Marsh until about 700 A.D.
We also collected a "sledge-hammer" multichannel seismic reflection profile across the drumlin we are standing on. Results suggest that there are about 18 m (58') of unconsolidated sediment beneath the crest of the drumlin. The bedrock reflection is quite distinct and indicates a "high" with about 6 m (18') of relief. Although these results are from only one of thousands of drumlins in the area, they do suggest that the drumlins here may be controlled by relief on an eroded bedrock surface.
What is the origin of the Montezuma channels? The facts are that it is a southward-directed, dendritic system with a maximum length to width ratio of about 5:1; it is a broad, shallow system filled with up to 55 m (180') of sediment; basal coarse-grained sediments are overlain by lake clays; and, the entire system feeds into the north end of Cayuga Lake despite the fact that contemporary outlet drainage is to the north.
One interpretation is that these channels represent subaerial preglacial drainage from a stabilized ice margin north of the channels. However, there is little direct evidence for a stabilized ice-margin here (Muller and Cadwell, 1986) and the dendritic pattern is inconsistent with preglacial streams which are typically braided. Also, a preglacial stream origin would require subaerial conditions followed by a sub-lacustrine environment.
An alternative hypothesis is that the Montezuma channels were carved by subglacial meltwaters that were funneled into the Cayuga Lake valley. A dendritic pattern has been theoretically predicted for subglacial drainage systems which Boulton and Hindmarsh (1987) argue are required to drain excess water during stable subglacial deformation to form drumlins. A subglacial origin for these channels would also allow for direct evolution of environments from subglacial fluvial to glacio-lacustrine and then lacustrine (without an intervening subaerial stage) as the ice sheet retreated. Muller and Cadwell's (1986) surficial geologic map of the Finger Lakes indicates the presence of a similar, but less well-developed, channel at the north end of Seneca Lake which has an esker-like ridge along its northern axial thalweg.
From our stop on Armitage Road along the western branch of the Montezuma channels, we will head east and drive across the eastern branch of the channels where you can get a good "feel" for the width of these channels. We will then drive south to Route 20 and then east to our last stop at Skaneateles which will take us across the southern edge of the Weedsport drumlin field.

STOP 12: NORTH END OF SKANEATELES LAKE
(WRAP-UP DISCUSSION)
This scenic stop at the north end of Skaneateles Lake is designed to provide us with an opportunity to collectively discuss the subsurface geophysical/geologic data we have examined during the past day and a half, and its implications for the origin and evolution of the Finger Lakes. These data document the large scale erosion (up to 298 m; 978' below sea-level) and infill (up to 270m; 886') of the Finger Lake valleys (Mullins and Hinchey, 1989) including a thick Valley Heads sequence. Seismic stratigraphic relationships indicate that the sediment-fill beneath the Finger Lakes post-dates deposition of Valley Heads at 13-14 ka. Thus, timing of the erosion of the Finger Lakes can only loosely be constrained as sometime between the Devonian and 13-14 ka! If pre-late Wisconsin sediments were deposited beneath the Finger Lake valleys they have been removed by subsequent erosion. This implies that the Finger Lakes were at least deepened by late Wisconsin glaciation. Hughes' (1987) model of Laurentide Ice Sheet deglaciation for 14 ka suggests that ice streamed into the Finger Lakes region from the St. Lawrence Lowlands/Ontario Basin as the ice sheet began to collapse. Based on our subsurface data integrated with Muller and Cadwell's (1986) surficial map, we suggest a highly digitate ice margin in the Finger Lakes region with streams of more rapidly flowing ice moving down the Finger Lake valleys. At this time (13-14 ka) large volumes of coarse-grained debris were being pumped subglacially down through the Finger Lake valleys, perhaps by channelized subglacial meltwaters, and ultimately deposited as the Valley Heads moraines. An alternative interpretation for this stage is that an ice dome developed in the Lake Ontario basin and that rapid ice flow through the Finger Lake valleys was in the form of outlet glaciers which may have also been accompanied by channelized subglacial meltwater (Ridky and Bindshadler, 1990).
As the ice margin began to pull-off its Valley Heads position channelized subglacial meltwaters continued to pump large volumes of finer-grained debris into the Finger Lakes valleys as subaqueous outwash (sequence II; Fig. 41). In this regard we agree with Gustavson and Boothroyd (1987) that subglacial streams (rather than "dirt machines") were the primary source of glacio-fluvial and glacio-lacustrine sediment along the southern margin of the Laurentide Ice Sheet.
Once ice margins had retreated to the north end of the Finger Lake valleys, classical proglacial lacustrine sedimentation continued to fill the valleys which is recorded on our reflection profiles as highly-reflective sequence IV. At this time, with the north ends of the valleys dammed by ice, lake levels were considerably higher than today. However, as soon as ice retreated from the north ends of the valleys, lake levels dropped rapidly and a drainage reversal (from south-to north-directed) occurred (Mullins and Hinchey, 1989). This event is recorded on our profiles by sequence V which thickens to the south in all the lake basins. When lake levels dropped, highstand deltas were left hanging on valley walls and numerous gorges were eroded as local base level was dramatically lowered.
After the ice completely withdrew from the Finger Lakes region ~12 ka (Hughes, 1987), differential isostatic rebound in the north resulted in the flooding of the south ends of the Finger Lakes valleys as evidenced by lake clays overlying fluvial/alluvial sands and gravels in drill cores. Subsequent to this flooding event, post-glacial drainage from the south has partially filled the southern ends of the Finger Lake valleys, while accumulating a thin, transparent "blanket" of sediment beneath the lakes.
The most recent chapter in the natural history of the Finger Lakes is recorded in the cyclic sequence of peats and lake clays recovered in the Canandaigua drill core. There are about six of these cycles that overlay fluvial/alluvial sands and gravels. Do these cycles represent climatically driven lake level fluctuations or post-glacial rebound oscillations? Whatever their cause, the fact that there are about six cycle in the post-glacial (<~12 ka) section suggests that they have a periodicity on the order of 2 ka. Our working hypothesis is that they were climatically driven and may record an environmental record of wet and dry cycles for the Finger Lakes region during the past 12 ka. We continue to work on these cyclic sequences and should have more definitive results in the near future.
We hope that you have not only enjoyed this unique field trip but that you have also gained a better appreciation of the "unseen" geology beneath the Finger Lake valleys. If we are to fully comprehend the Quaternary geologic history of regions such as the Finger Lakes it will be necessary to record subsurface as well as surficial geology. We hope that our integrated subsurface geophysical and geological approach has revealed at least a part of the "barely suspected missing chapter in the istory of the Finger Lakes" alluded to by Bloom (1984)

A1: THE FOUNDERS OF AMERICAN GEOLOGY
THE FOUNDERS OF AMERICAN GEOLOGY: A VISIT TO THEIR TOMBS, LABS, AND THEIR FAVORITE EXPOSURES: THE DEVONIAN LIMESTONES OF THE CAPITAL DISTRICT; A STUDY OF THE SEQUENCE STRATIGRAPHY OF THESE LIMESTONES
GERALD M. FRIEDMAN
Brooklyn College and the Graduate School of CUNY
Northeastern Science Foundation affiliated with Brooklyn College-CUNY
15 Third Street, Box 746
Located along the Helderberg Escarpment this classic site is on hallowed ground. Amos Eaton (1776-1842), Ebenezer Emmons (1799-1863), James Hall (1811-1898), William W Mather (1804-1859), Sir Charles Lyell (1797-1875), Benjamin Silliman (1779-1864), James D. Dana (1813-1895), Louis Agassiz (1807-1873), and Sir William E. Logan (1798-1875) have trod here before you, and we will view the memorial plaque erected in their honor. The field sites expose a large variety of Lower and Middle Devonian limestones, including coral reefs, stromatoporoid reefs, storm deposits, stromatolite facies, skeletal-and lime mud facies, solution-collapse features, and karst. This diversity of facies will be studied in terms of transgressive-regressive cycles, known as parasequences, which are defined as conformable successions of genetically-related beds bounded by surfaces of erosion, called parasequence surfaces.
HISTORY OF GEOLOGY
Before viewing the sequence stratigraphy of the Devonian we will pay tribute to the founders of American geology on whose concepts modern geology has built. Among those particular attention will be given to Amos Eaton, James Hall, and Ebenezer Emmons, whose debt we have incurred as builders of our science and at whose graves we will pay our respects. This field trip will begin in Troy, N.Y.

A1: The Founders of American Geology

STOP 1. Amos Eaton grave
Visit the grave of the father of American geology Amos Eaton

STOP 2a. James Hall (Lot 93, Section 18)
James Hall. - James Hall was the single most prominent American geologist of the 19th century. The impressive honors he received are worth listing chronologically. Hall obtained the degrees of A.B. and A.M. from Rensselaer in 1831 and 1832. In 1837 he was elected Member of the Imperial Mineralogical Society of St. Petersburg, Russia. In 1840 he was one of the founders of the American Association of Geologists which became the American Association for the Advancement of Science. In 1843 he was elected correspondent of the Academy of Natural Sciences of Philadelphia. In 1848 he was elected Foreign Member of the Geological Society of London, the number of foreign members being limited to 50. In 1848 he was elected fellow of the American Academy of Arts and Sciences. In 1856 he became President of the American Association for the Advancement of Science and in 1863 he was named, by an Act of Congress, to be one of the 50 original members of the National Academy of Science. The King of Italy conferred on him the title of Commander of the Order dei Santi Maurizzio e Lazzaro. Many other honors too numerous to he cited may he added.

STOP 2b. Ebenezer Emmons (Lot 46, Section 6).
Ebenezer Emmons.--alumnus and Junior Professor at Rensselaer, member of the New York State Geological Survey, founder of the North Carolina Geological Survey, and State Geologist of North Carolina; father of the Taconic System. A graduate of Rensselaer in the first class of 1826, Emmons had been inspired by Eaton. Emmons became Junior Professor at Rensselaer, a position he held for ten years, and a member of the New York State Geological Survey in 1836. Later he was State Geologist of North Carolina, spreading Rensselaer's influence in American geology through his textbooks and advocacy of the Taconic system.· Emmons had noted the presence of a group of rocks between the Potsdam Sandstone, the lowest of the sedimentary formations in New York and what was at the time called the Primitive Rocks of Central Vermont. This interval he proposed to call the Taconic System. Emmons acquainted the public with the Adirondack Region and gave the names to principal mountains. Classics which Emmons published include Manual of Mineralogy and Geology (1826), Report on the Second Geological District of New York (1842), Natural History of New York (1848), American Geology Containing a Statement of Principles of the Science With Full Illustrations of the Characteristic American Fossils (1854), Treatise Upon American Geology (1854), The Swamplands of North Carolina (1860), and Textbook of Geology (1860).
The antagonism of Hall helped chase Emmons out of New York. Yet in death their graves, close to each other, make their old controversy seem remote. Hall never acknowledged Emmons' thought-provoking studies on the Adirondack and Taconic Regions. One of the Adirondack peaks has been named Mount Emmons.

STOP 3. James Hall office and lab
The annex to Sunshine School is the historical laboratory of James Hall. For fifty years this building served as his office and laboratory.

STOP 4. Indian Ladder Trail at the John Boyd Thacher State Park.
Before descending to see the exposures read the sections titled Significance, the Stratigraphic Column, and Parasequences. Study especially figure 5. Then descend.
Study the section as you descend to the base of the trail: identify the facies, parasequence surfaces, contacts, and formations. On your return to the top of the section measure the thickness of various stratigraphic and facies units and plot them on a striplog or in a notebook. Compare your data with those shown on figure 5. After completion of the exercise visit the memorial plaque at the top of the trail near Mine Lot Creek parking lot. It is this plaque which explains why the ground on which you tread at this site is sacred.

A2: GEOLOGY AND GEOCHRONOLOGY OF THE SOUTHERN ADIRONDACKS
Hamilton, NY 13346
PROLOGUE
Geologic investigations of the Adirondack Region began in the nineteenth century with the early surveys of Ebenezer Emmons and later with important contributions from Kemp, Smyth, and Cushing (see Buddington 1939, for complete bibliographic references of these and other early workers). in the first three decades of the twentieth century a large number of significant publications were forthcoming from Miller, Newland, Alling, and Balk, as well as those cited previously, including Buddington. The essence of these contributions is summarized in Buddington's classic Geological Society of America Memoir (1939) entitled "Adirondack Igneous Rocks and their Metamorphism". The central, dominant theme of this work is that the Adirondacks consist of a vast collection of intrusive igneous complexes ranging in composition from anorthosite to granite. This consensus view was strongly supported by a wealth of field and chemical data and may be regarded as comprising Phase I in the history of Adirondack geology. The culmination of Phase I corresponds with the · publication of U.S. Geological Survey Professional Papers 376 and 377 by Buddington and Leonard (1962) and Leonard and Buddington (1964 ), respectively. These works were the result of government sponsored mineral exploration efforts during World War II. Both reports manifest the classical view of the Adirondacks as an igneous-plutonic domain.
Phase II begins with Engel and Engel (1958, 1964) in the lowlands and Walton and deWaard (1963) and deWaard (1964, 1965) in the highlands. Conceptually, this phase is characterized by paradigms of stratigraphy and stratigraphic correlation. Its modus operandi was the recognition and definition of rock sequences, interpreted as stratigraphic, and correlated over great distances. Depending upon the particular investigators, this stratigraphic framework was cross-bred with varying degrees of granitization and metasomatic transformations.
A late stage of Phase II is represented by the investigations of McLelland in the highlands (McLelland and Isachsen, 1986) and Carl, Foose, deLorraine, and others in the lowlands (see Carl et al. 1990 for references). In this stage, metavolcanics played a burgeoning role in the interpretation of Adirondack layered sequences (Whitney and Olmsted 1989). In addition, structural investigations documented the existence of large fold-nappe structures within most of the Adirondacks (deWaard 1964, McLelland 1984). A characteristic of this stage of Phase II was to downgrade the importance of widespread igneous intrusion and to substitute for it metamorphic processes involving recrystallization of stratified volcanics and sediments into layered gneisses modified by local anatectic effects (Carl et al. 1990; Whitney and Olmsted 1989).
Phase III of Adirondack geology began in the mid-1970's when Eric Essene, together with his students John Valley and Steve Bohlen (see Bohlen et al. 1985 and Valley et al. 1990) established a quantitative framework for Adirondack pressure, temperature, and fluid conditions during metamorphism. This approach has been significantly augmented by the oxygen isotope studies of John Valley and Jean Morrison (see Morrison and Valley 1988 for complete reference) and the U-Pb studies of Klaus Mezger (1990), all of which have provided critical data that constrain models of Adirondack evolution. Simultaneously, McLelland and Chiarenzelli (McLelland et al 1988, 1991a,b; McLelland and Chiarenzelli 1990, 1991) have conducted a U-Pb zircon study of the Adirondacks in order to follow up on Silver's (1969) pioneering, landmark investigations. The quantitative results of these research programs have provided unequivocal boundary conditions with which any interpretations of Adirondack geology must be consistent. These results and associated boundary conditions are presented in the text that follows. Significantly, and interestingly, the numbers demonstrate that Phase I interpretations were much closer to the truth than the elaborate stratigraphic models of Phase II. It has become increasingly clear that, in the Adirondacks, intrusive igneous rocks greatly dominate over metavolcanics, or even possible candidates for metavolcanics. Accordingly, it has become evident that layering in orthogneisses is not of primary origin but represents examples of tectonic layering of the sort described by Davidson (1984) in tectonites referred to as straight gneisses. Highly strained rocks of this sort have been described for the Piseco anticline by McLelland (1984) and are common throughout the region.
In conclusion, modem quantitative petrologic and isotopic data strongly indicates that the early, and classic, interpretations of the Adirondacks were, in the main, very nearly correct and herein lies a lesson worth pondering. These results offer additional support for the well documented thesis that granites are plutonic, intrusive rocks and that attempts to form them by circuitous, non-intrusive mechanisms are both outdated and destined to failure. This assessment applies equally well to long discredited examples of granitization and to more modern attempts to account for granites by metamorphosing acidic volcanics. Among the critical observations related to these conclusions are quantitative results from geothermometry, geobarometry, geochronology, and petrochemistry. Combined with a modem understanding of tectonic layering, these considerations can greatly constrain the interpretation of complex geologic terranes, as described below for the southern Adirondack region.

STOP 1. Peck Lake Fm.
This exposure along Rt. 29A just north of Peck Lake is the type locality of the sillimanite-garnet-biotite-quartz-feldspar gneisses (kinzigites) of the Peck Lake Fm. in addition, there are exposed excellent minor folds of several generations. Note that the F1 folds rotate an earlier foliation. The white quartzo-feldspathic layers in the kinzigites consist of quartz, two feldspars,and garnet and are believed to be anatectic and have been folded by F1 indicating pre-F1 metamorphic events. Spinel has been found enclosed in garnets at this outcrop. The similarity of the Peck Lake Fm. to the Major Paragneiss of the Lowlands suggests that the Adirondacks were contiguous at the time of deposition of the rocks.

STOP 2. Irving Pond Fm.
0.5 mile north of Nick Stoner's Inn, Canada Lake. Very near hinge line of F1Canada Lake isocline.
The outer portion of the Irving Pond Fm. is exposed in low cuts along the east side of Rt. 29A just prior to the crest in the road heading north.
At the southern end of the cut typical, massive quartzites of the Irving Pond are seen. Proceeding north the quartzites become "dirtier" until they develop sillimanite-garnet-biotite-feldspar (kinzigites) layers along with quartzite.
At the northern end of the cut, and approximately on the Irving Pond/Canada Lake Fm. contact there occurs an excellent set of F1minor folds. Polished slabs and thin sections demonstrate that these fold an earlier foliation defined by biotite flakes and flattened quartz grains.
At the southern end of the outcrop dark, fine grained metadiabase sheets crosscut the quartzite. Near the telephone pole erosional remnants of diabase appear to truncate approximately horizontal foliation in the quartzite suggesting that the diabase was emplaced after an early metamorphism. At the north end of the cut a diabase sheet of variable thickness is folded in the F1fold. The folding is interpreted as Ottawan, the diabase as AMCG in origin, and the early foliation as Elzevirian. This is consistent with the presence of quartzite xenoliths in the ca. 1300 Ma tonalites.
The Irving Pond Fm. is the uppermost unit in the lithotectonic sequence of the southern Adirondacks. Its present thickness is close to 1000 meters, and it is exposed across strike for approximately 4000 meters. Throughout this section massive quartzites dominate.

STOP 3. Canada Lake Charnockite
(>1233 Ma, table 1, sample AM-87-13. Now fixed at 1251±43)
Large roadcuts expose the type section of the Canada Lake charnockite. Lithologically the charnockite consists of 20-30% quartz, 40-50% mesoperthite, 20-30% oligoclase, and 5-10% mafics. The occurrence of orthopyroxene is sporadic. These exposures exhibit the olive-drab coloration that is typical of charnockites. Note the strong foliation in the rock. Farther north along the highway there are exposed pink leucogranitic variants of this unit. The chemical composition of these is given in table 3 (ab-6). The whole rock chemistry of the charnockitic phase is similar to AM-86-17 in table 3. The lateral continuity of the Canada Lake is striking (fig. 2) but the presence of xenoliths reveals an intrusive origin.

STOP 4. Royal Mt. Tonalite
(> 1301 Ma, table 1, sample AM-86-12, now fixed at 1307±2 Ma).
Steep roadcuts, exposed across from the Canada Lake Store, expose typical examples of the early tonalitic rocks that occur within the southern and eastern Adirondacks and that manifest the presence, throughout the region, of collisional magmatic arcs of calcalkaline chemistry that existed along the eastern margin of Laurentia from ca. 1400-1200 Ma. Amalgamation of these arcs culminated in the Elzevirian Orogeny at ca. 1250-1220 Ma.
he whole rock chemistry of the tonalitic rocks is given in table 3 and important chemical trends are portrayed in figures 8, 9, and 10. Figure 7 shows the εNd characteristics of these rocks and emphasizes their petrologically juvenile character, i.e., they are not derived from any crustal rocks with long-term crustal residence but are essentially mantle derived (including derivation from melting of basaltic rock derived from the mantle at ca. 1300-1400 Ma). The εNd characteristics are compared with those from lowland tonalites and granitoids of similar age, and the similarity suggests that they are essentially the same, strongly suggesting contiguity across the entire Adirondacks at that time ( ∼1300 Ma).
A disrupted layer of amphibolitic material runs down the outcrop to road level at the east end of the outcrop. This, and other mafic sheets in the outcrop, are interpreted as dikes and sheets coeval with the tonalite. In the eastern Adirondacks it has been possible to document mutually crosscutting relationships between these rock types. Also documented there are xenoliths of kinzigitic rock in the tonalites. Within the southern Adirondacks xenoliths of quartzite similar to the Irving Pond Fm. have been found in the tonalite.

STOP 5. Rooster Hill megacrystic gneiss at the north end of Stoner Lake
This distinctive unit belongs to the AMCG suite and is widespread in the southern Adirondacks. Here the unit consists of a monotonous series of unlayered to poorly layered gneisses characterized by large (1-4") megacrysts of perthite and microcline perthite. For the most part these megacrysts have been flattened in the plane of foliation, however, a few megacrysts are situated at high angles to the foliation and show tails. The groundmass consists of quartz, oligoclase, biotite, hornblende, garnet, and occasional orthopyroxene. An igneous rock analogue would be monzonite to quartz-monzonite (see table 3 for chemical composition) and the presence of orthopyroxene makes the rock mangeritic to charnockitic.
The contacts of the Rooster Hill megacrystic gneiss are everywhere conformable, but the presence of xenoliths of kinzigite indicate its intrusive nature. Rocks such as the Rooster Hill are interpreted as derived from melting of ca. 1300 Ma tonalitic and lower crustal granitoid rocks with heat derived from large AMCG gabbroic intrusions that would ultimately differentiate to anorthosite. This suggestion is consistent with the εNd trends of AMCG and tonalitic rocks in figure 7a and with the REE distributions shown in figure 19, where it appears that melting of tonalite so as to leave a plagioclase-rich residue can give the AMCG REE-trends.

Low roadcut in kinzigites

Long roadcuts of pink quartzofeldspathic gneisses and metasediments
Long roadcuts of pink quartzofeldspathic gneisses and metasediments of intruded metagabbro and anorthosite metagabbro. The igneous rocks are believed to belong to the AMCG suite.

Roadcut of anorthositic metagabbro and metanorite of AMCG suite.

Excellent examples of anorthositic gabbros
Roadcut on west side of highway shows excellent examples of anorthositic gabbros intrusive into layered pink and light green quartzofeldspathic gneisses.

Roadcuts of quartzites and other metasediments of the Sacandaga Fm.
Mezger (1990) obtained a U-Pb garnet age of ca. 1154 from these rocks.

Red-stained AMCG quartzofeldspathic gneisses that have been faulted along NNE fractures.

STOP 6. Core rocks of the Piseco anticline.
This stop lies along the hinge line of the F2 Piseco anticline near its domical culmination at Piseco Lake. The rocks here are typical of the granitic facies of quartzofeldspathic gneisses such as occur in the Piseco anticline and in other large anticlinal structures, for example Snowy Mt. dome, Oregon dome.
The pink "granitic" gneisses of the Piseco anticline do not exhibit marked lithologic variation. Locally grain size is variable and in places megacrysts seem to have been largely grain size reduced and only a few small remnants of cores are seen. The open folds at this locality are minor folds of the F2 event. Their axes trend N70W and plunge 10-15° SE parallel to the axis of the Piseco anticline.
The most striking aspect of the gneisses in the Piseco anticline is their well-developed lineation. This is expressed by rod, or pencil-like, structures which are clearly the result of ductile extension of quartz and feldspar grains in a granitic protolith. The high temperature, grain size reduction that has occurred results in a mylonite. Where recognizable, early F1isoclinal fold axes parallel the lineation.
These rocks are similar in age and chemistry to other AMCG granites and are considered to be part of that suite.
Smooth outcrops of Piseco Core rocks showing exceptionally strong mylonitic ribbon lineations.

STOP 7. 3.3 miles east of Speculator, New York.
Typical Adirondack marble is exposed in roadcuts on both sides of the highway. These exposures show examples of the extreme ductility of the carbonate-rich units. The south wall of the roadcut is particularly striking, for here relatively brittle layers of garnetiferous amphibolite have been intensely boudinaged and broken. The marbles, on the other hand, have yielded plastically and flowed extensively during the deformation. As a result, the marble-amphibolite and marble-charnockite relationships are similar to those that would be expected between magma and country rock. Numerous rotated, angular blocks of amphibolite and charnockite are scattered throughout the marble in the fashion of xenoliths in igneous intrusions. At the eastern end of the outcrop tight isoclinal folds of amphibolite and metapelitic gneisses have been broken apart and rotated. The isolated fold noses that remain "floating" in the marble have been aptly termed "tectonic fish". The early, isoclinal folds rotate on earlier foliation. The garnetiferous amphibolites have typical igneous compositions and are interpreted as flows or sills.
Near the west end of the outcrop a boudin of charnockite is well exposed. McLelland and others (1987) have presented evidence that boudin represents a local example of charnockitization by carbonic metamorphism. However, granites of similar composition outside the marble do not develop orthopyroxene, demonstrating the local nature of the process and the limited permeation of the fluid phase.
Exposed at several places in the roadcut are crosscutting veins of tourmaline and quartz displaying a symplectic type of intergrowth. Other veins include hornblende-and sphene-bearing pegmatites.
Almost certainly these marbles are of inorganic origin. No calcium carbonate secreting organisms appear to have existed during the time in which these carbonates were deposited(> 1200 Ma ago). Presumably the graphite represents remains of stromatolite-like binding algae that operated in shallow water, intertidal zones. This is consistent with the presence of evaporitic minerals, such as gypsum, in Lowland marbles.
At the eastern end of the outcrop coarse diopside and tremolite are developed in almost monomineralic layers. Valley et al. (1983) showed that the breakdown of almost Mg-pure tremolite to enstatite, diopside, and quartz in these rocks requires low water activity at the regional P,T conditions. Similarly, the local presence of wollastonite requires lowering of CO2 activity, presumably by H2O. These contrasts demonstrate the highly variable composition of the fluid phase and are consistent with a channelized fluid phase within a largely fluid-absent region.

Large roadcuts in well-layered, pink quartzofeldspathic gneisses
Large roadcuts in well-layered, pink quartzofeldspathic gneisses with subordinate amphibolite and calcsilicate rock. The layering here is believed to be tectonic in origin, and the granitic layers represent an intensely deformed granite. The calcsilicate layers may be deformed xenoliths.

STOP 8. One half mile south of jct of old Rt. 30 and with new Rt. 30.
Anorthositic rocks on the SW margin of the Oregon Dome.
On the west side of the highway a small roadcut exposes typical Adirondack anorthosite and related phases.
The glacially smoothed upper surface of the roadcut reveals the presence of three major igneous phases: 1) a dark, pyroxene-rich dike that crosscuts the anorthosite, contains anorthosite xenoliths, and contains a large irregular, disrupted mass of sulfidic calcsilicate; 2) a coarse grained, Marcy-type anorthosite facies with andesine crystals 6-8" across; and 3) a fine grained anorthositic phase. Some of the coarse grained facies has been crushed and these portions bear some resemblance to the finer grained phase (note, for example, those places where fractures cross large andesine grains and produce finer grained material). However, close inspection of the finer grained material reveals the presence of ophitic texture with pyroxenes of approximately the same size as the plagioclase, and this texture and association are much better explained as igneous in origin. Therefore, the texture of the fine grained phase is interpreted as igneous in origin and may be due to chilling near the contact of the Oregon Dome massif. By contrast, large (3-4 em) rafts of coarse grained, ophitic gabbroic anorthosite seem to be "flat" in the fine grained phase. Analyses of typical anorthositic rocks are shown in Table 5.
The pyroxene-rich ferrogabbro dike shows "soft" contacts with the anorthosite and is interpreted as essentially coeval. Zircons from it give a minimum age of 1087 Ma and, by comparison with other Adirondack anorthosites, its emplacement age is set at ca. 1135 Ma. The composition of the ferrogabbro is shown in table 5 where it is seen to be rich in TiO2 and P2O5. Similar rocks occur together with other Adirondack anorthosites and are interpreted as late, Fe-enriched differentiates of a Fenner-type fractionation trend (see fig. 14). It is suggested that further differentiation within these rocks can result in liquid immiscibility and the production of magnetite-ilmenite liquids.
The upper, weathered surface of the outcrop affords the best vantage point for studying the textures and mineralogy of the anorthositic rocks. In several places there can be seen excellent examples of garnet coronas of the type that are common throughout Adirondack anorthosites. These coronas are characterized by garnet rims developed around iron-titanium oxides and pyroxenes. Recently McLelland and Whitney (1977) have succeeded in describing the development of these coronas according to the following generalized reaction:
Orthopyroxene + Plagioclase + Fe-bearing oxide + Quartz = Garnet+ Clinopyroxene.
This reaction is similar to one proposed by de Waard (1965) but includes Fe-oxide and quartz as necessary reactant phases. The products are typomorphic of the garnet-clinopyroxene subfacies of the granulite facies (de Waard 1965). The application of various geothermometers to the phases present suggests that the P,T conditions of metamorphism were approximately 8 kb and 700±50°C respectively.

Minor marble, amphibolite, and calcsilicate rock.
Predominantly very light colored sillimanite-garnet-quartz-feldspar leucogneisses interpreted as minimum-melt granitic due to anatexis of kinzigite near Oregon dome anorthosite. Enclaves of spinel-and sillimanite-bearing metapelite are present.

Roadcuts in garnetiferous metasediment.
To the west of the intersection are roadcuts in garnetiferous metasediment. A large NNE normal fault passes through here and fault breccias may be found in the roadcut and the woods beyond.

Entering granitic-charnockitic gneiss
Entering granitic-charnockitic gneiss on northern limb of the Glens Falls syncline. Note that dips of foliation are to the south.

Downdropped block of lower Paleozoic sediments.
Entering town of Wells which is situated on a downdropped block of lower Paleozoic sediments. The minimum displacement along the NNE border faults has been determined to be at least 1,000 meters.

Silver Bells ski area to the east.
The slopes of the ski hill are underlain by coarse anorthositic gabbro that continues to the west and forms the large sheet just south of Speculator.

Entrance to Sacandaga public campsite.
On the north side of NY Rt. 30 are quartzo-feldspathic gneisses and calcsilicates. An F1recumbent fold trends sub-parallel to the outcrop and along its hinge line dips become vertical.

Stop 9. Pumpkin Hollow.
Large roadcuts on the east side of Rt. 30 expose excellent samples of the Sacandaga Fm. At the northern end of the outcrop typical two pyroxene-plagioclase granulites can be seen. The central part of the outcrop contains good light-colored garnet-microcline-quartz gneisses (leucogneisses). Although the weathered surfaces of these rocks are often dark due to staining, fresh samples display the typical white vs. grey color of the Sacandaga Fm. The characteristic and excellent layering of the Sacandaga Fm. is clearly developed. Note the strong flattening parallel to layering. Towards the southern end of the outcrop calc-silicates and marbles make their entrance into the section. At one fresh surface a thin layer of diopsidic marble is exposed.
At the far southern end of the roadcut there exists an exposure of the contact between the quartzo-feldspathic gneisses of the Piseco anticline and the overlying Sacandaga Fm. The hills to the south are composed of homogenous quartzo-feldspathic gneisses coring the Piseco anticline (note how ruggedly this massive unit weathers). The Sacandaga Fm. here has a northerly dip off the northern flank of the Piseco anticline and begins its descent into the southern limb of the Glens Falls syncline.
The pronounced flaggy layering in the Sacandaga Fm. is not of primary sedimentary or volcanic origin. Instead it is tectonic layering within a "straight" gneiss. Hand specimen and microscopic inspection of the light layers, particularly, reveals the existence of extreme grain size reduction and ductile flow. Long quartz rods consist of rectangular compartments of recovered quart and annealed feldspar grains occur throughout. The rock is clearly a mylonite with its mylonitic fabric parallel to compositional layering.
The chemistry of the light colored layers in the Sacandaga Fm. indicates that they are minimum melt granites. As one proceeds away from the core of the Piseco anticline, these granitic layers can be traced into less deformed sheets and veins of coarse granite and pegmatite. In the most illustrative cases the granitic material forms anatomizing sheets that get grain size reduced and drawn into parallelism as high strain zones are approached. The Sacandaga Fm. is interpreted as an end result of this process and represents a mylonitized migmatite envelope developed in metapelites where they were intruded by AMCG granites at ca. 1150 Ma and then intensely strained during the Ottawan Orogeny at ca. 1050 Ma. This interpretation is consistent with field relationships, the presence of spinel and sillimanite restites in the leucosomes, and with the fact that similar metapelitic rocks are crosscut by ca. 1300 Ma tonalites. The latter observation makes the Sacandaga Fm. protoliths older than the ca. 1150 Ma granitic rocks in the Piseco anticline and makes an intrusive relationship obligatory despite the conformable contact at the south end of the roadcut.

Southerly dipping quartzo-feldspathic gneisses
In long roadcuts of southerly dipping pink, quartzo-feldspathic gneisses with tectonic layering. The coarse grain size of the gneissic precursors can be seen in many layers.

A3: PATTERNS OF PHYLETIC EVOLUTION IN THE TRENTON GROUP
ROBERT TITUS
Oneonta, New York 13820
The Trenton Group has been the subject of 60 years of continuous biostratigraphic study since Marshall Kay began his work during the early 1930's. The unit displays a remarkably rich and diverse fossil assemblage which, along with its facies patterns, is now quite well known. The Trenton Group is thus very well suited for research directed at understanding patterns of evolution. This ongoing research program is currently focused on recognizing patterns of intraspecific clinal variation and relating these to facies change in order to develop comprehensive records of evolutionary events. Two case studies are now complete. Evolution within the crinoid genus Ectenocrinus has been described (Titus, 1989). A similar paper on the brachiopod genus Sowerbyella is pending (Titus, in preparation). This field guide will serve as an appendix to both of those papers.

A3: Patterns of Phyletic Evolution in the Trenton Group

STOP 1. The Napanee Limestone
The strata here are primarily thick bedded, black micrites which have been interpreted as a nearshore lagoon facies. Sowerbyella is abundant. This form has traditionally been identified as S. punctostriatus. It is herein reinterpreted as the quiet water, mud bottom clinal variant of S. curdsvillensis. Examine the brachial interiors and see the preponderance of simple forms. Medial septa can be seen but muscle scars, vascular markings and sub-peripheral thickenings are uncommon. The pedicle exterior usually displays alate corners and a well developed medial fold giving this valve a peaked appearance.

STOP 2. The Kings Falls Limestone
The lower strata here are primarily thick bedded, coarse grained biosparites which have been interpreted as a barrier shoal facies, lying offshore of the Napanee lagoon facies. Toward the top of the outcrop the facies grades into a shallow shelf facies. While, at this location, these strata overlie those of the lagoon facies, presumably there were contemporaneous lagoonal facies elsewhere. Sowerbyella is very abundant at the base of this outcrop. This form is larger than the one in the lagoon facies. Most of the brachial interiors are quite ornate. They have medial septa, muscle scars, vascular markings and sub-peripheral thickenings. The pedicle exteriors have blunt corners. They don't often show medial folds. Instead they tend to be flattened or broadly rounded. This form has traditionally been identified as S. curdsvillensis. It is herein reinterpreted as the agitated facies clinal variant of a more broadly defined S. curdsvillensis. By collecting enough brachial interiors at these two outcrops, an assemblage of forms can soon be put together that show the gradation between the lagoon and the shoal clinal variants.

STOP 3. The Sugar River Limestone
There is a prominent re-entrant below the bridge which can be traced downstream. This is a thick bentonite which lies 10 m (32 ft.) below the top of the Sugar River Limestone. Sowerbyella is rare in the deeper water facies above this bentonite, but common in the shallower facies below. Examine the strata several meters below the bentonite. The common form of Sowerbyella here is the mud bottom, quiet water form. Although some of the brachial interiors are ornate, most are plain. Medial septa are seen but other features are uncommon. The form is relatively small. Pedicle exteriors often display a medial fold and alate corners. This location records a return of both quiet water conditions and the quiet water clinal variant of Sowerbyella. Upstream into the highest strata of the Sugar River Limestone, and for a considerable distance into the overlying Denley Limestone, Sowerbyella is quite scarce. This zone is part of the first Sowerbyella bottleneck.
The next location is designed to display an example of model 3 clinal variation. The middle Trentonian crinoid genus Ectenocrinus occupied a shallow to deep shelf range of environments. Because of bank margin steepening, the deep end of its range was deteriorating while shallowing facies offered opportunities for Ectenocrinus in shallow water environments. The result is a kind of clinal orthoselection.

STOP 4. The Sugar River And Denley Limestones
At the base of the falls a re-entrant ca be seen. This is the same bentonite which was observed at Mill Creek in Lowville. Here it is also 10 m (32 ft.) below the top of the Sugar River Limestone. The bentonite is a marker bed which is found at the same level at all outcrops from Mill Creek, Lowville to Sugar River. It has not been found at Deer River or at any of the Mohawk Valley locations.
Examine the several meters of strata above the falls. Ectenocrinus is represented by moderately abundant columnals. Look carefully as these columnals are small. It is very helpful to bring a water container and pour water on columnal rich beds. This brings out the contrast between the columnals and their micritic groundmass. Ectenocrinus is easily recognized by its trimeric morphology. Each columnal is composed of three elements fused together along faintly visible sutures. The most common form is a triangle with very rounded corners. At first glance the lumina appear to be triangular, and many are. But you will soon notice that many also have very poorly developed 4th and 5th points, along with three long and attenuated points (Fig. 5i-5m). All specimens at this level belong to the species E. triangulus.
Climb to the level above where the trail intersects the stream. Here and for quite a distance upstream Ectenocrinus columnals are different. Now they are generally rounder and the lumina are composed of more equal sized points (Fig. 5s-Sv). Forms at this level are intermediate between E. triangulus and its descendent E. simplex. Continue upstream and observe the increasingly abundant columnals of Ectenocrinus. The transition from E. triangulus to E. simplex is not just one of morphology. E. triangulus was a relatively stenotopic form which never became especially abundant. The descendent, E. simplex, was altogether different. It was eurytopic and one of the dominant forms in the upper Trenton Group, a "weed" crinoid. This evolutionary event records an ecological transition from the K-strategist ancestor to the r-strategist descendent.
The last locations are designed to illustrate model 2 examples of clinal variation. Sowerbyella passed through two facies bottlenecks, one at the base of the middle Trentonian and one at the base of the upper Trentonian (Fig. 3, arrows). The best place to study the Sowerbyella of the middle Trentonian is at Mill Creek, Lowville, but as that outcrop extends for such a long distance along the stream, it is not practical to include this location in a one-day trip. We will examine middle Trentonian forms at other locations, stops 5 and 6.

STOP 5. The Denley Limestone
At this level the transition to Ectenocrinus simplex is complete. Virtually all Ectenocrinus columnals, upstream from the bridge, are round with pentagonal lumina (Fig. 5z-5aa). Sowerbyella is not common here but the specimens which can be seen are of interest. They are nearly identical to the quiet water lower Trentonian forms. They have plain brachial interiors; the pedicle exteriors have medial ridges and alate corners.

STOP 6. The Denley Limestone
The exposure here is of the middle Denley Limestone. The facies are the shallow shelf possibly grading into the barrier (Fig. 3). Several types of Sowerbyella can be recognized from the brachial interior structure. Many have plain interiors. While medial septa are present, none of the other internal structures are seen. The other type has an ornate brachial interior. Medial septa, muscle scars and sub-peripheral thickenings can be seen, some or all, on the same interiors. The plain forms found at this outcrop are typical of the Denley's deeper shelf facies while the ornate forms, although never very common, are typical of the more shallow and agitated facies. Significantly, vascular markings are quite unusual and these ornate forms are never as large as their lower Trentonian equivalents. Pedicle exteriors are more inflated and rounded. This is Sowerbyella n. sp.

STOP 7. The Upper Denley Limestone
The best location to see Sowerbyella next is at the outcrop of the lower Steuben Limestone on Rt. 177 just west of Rodman, but this is too far away for our trip today. The Rodman exposure shows Sowerbyella within the second bottleneck (Fig. 3, arrow). Specimens there are small and have a well developed, broadly rounded medial fold. At Talcottsville we can see Sowerbyella in the barrier facies just below this second bottleneck. The form is abundant up to the base of the falls and then quite a bit less common in the bottlenecking beds above. The specimens here are, for the most part, characterized by well inflated pedicle exteriors which sometimes display the broadly rounded medial folds typical of the second bottleneck. Brachial interiors are generally plain. Notice the magnificent display of large symmetrical ripple marks (pararipples) here.

STOP 8. The Hillier Limestone
The Hillier Limestone is exposed all along Wells Creek and Big Brook. The environment of deposition was quiet deep shelf and the deposits are mostly biomicrites. This location is above the second facies bottleneck and a third species of Sowerbyella is exposed. The form, S. subovalis, is characterized by a greatly inflated pedicle exterior with a broadly rounded medial fold. Brachial interiors are mostly plain. Medial septa are seen, and sometimes poorly developed sub-peripheral folds can be found, but muscle scars and vascular markings are absent. These traits are apparently inherited from the clinal variants of S.n. sp. which made it through the second bottleneck. The ones on Big Brook are larger than their middle Trentonian ancestors.

A4: PAC STRATIGRAPHY OF THE HELDERBERG GROUP
PAC STRATIGRAPHY OF THE HELDERBERG GROUP: CYCLE DEFINITION, ALLOGENIC SURFACES, HIERARCHY, CORRELATION AND RELATIONSHIP TO "VAIL" SEQUENCES
E.J. ANDERSON AND P.W. GOODWIN
GEOLOGY DEPARTMENT, TEMPLE UNIVERSITY
PHILADELPHIA, PA 19122
Sections at Thacher Park and Schoharie demonstrate our method of defining 6th order rock cycles (PACs) on the basis of facies patterns (as opposed to key lithologies). Cycle boundaries are placed at surfaces where deeper facies abruptly overlie shallower facies in a disjunct relationship. Several genetically distinct kinds of stratigraphic surfaces are well illustrated in these sections, including PAC boundaries, intracycle surfaces ( sea-level fall surfaces) and cryptic unconformities. Criteria for correlation of cycles (PACs) in the Manlius Formation between the two localities include: degree of facies change at PAC boundaries, tracing distinctive litho and bio facies, matching patterns of facies change through several cycles and matching the hierarchic pattern of cycles. In the Manlius Formation alone 14 or more 6th order cycles, as many as six 5th order cycles, parts of two 4th order cycles and an incomplete 3rd order B cycle are represented. The Manlius.Coeymans formational boundary is a cryptic unconformity that represents a 3rd order B "Vail" sequence boundary. The stratigraphic section at Schoharie from this unconformity to the Oriskany unconformity represents a nearly complete 3rd order B sequence and is tentatively divisible into a hierarchy of three 4th order and numerous 5th and 6th order sequences (rock cycles) . In terms of systems tract analysis the section equivalent to the Coeymans and Kalkberg Formations is identified as shelf margin wedge, the lowermost New Scotland (equivalent) rocks are the transgressive systems tract and the remaining New Scotland and Becraft Formations are the highstand systems tract.
Our purpose on this trip is to introduce participants to field application of allogenic, hierarchic cyclic stratigraphy. Participants are asked to begin with the assumption that the internal structure of the stratigraphic record is a product of a hierarchic set of cyclic processes that caused sea-level fluctuations. If this assumption is correct then the significant components of the stratigraphic record may include rock cycles arranged in a hierarchy, a variety of allogenic surfaces both within cycles and at their boundaries and a systematically arranged set of unconformities. We will attempt to provide a basis for discriminating the various types of cycles and surfaces and in doing so make the case that field analysis is dictated by assumed models. We would like to emphasize that our focus on these stratigraphic components of the rock record is different from the traditional focus on grains, laminations, beds and formations. New stratigraphic models therefore require new field methods and a different approach to recording data (see Anderson and Goodwin, 1990; Goodwin and Anderson, 1988 and Goodwin et al., 1986).
In this field exercise we will be applying a hierarchic stratigraphic model consisting of 5 orders of allogenic cycles:
3RD ORDER A (Supersequence) 8-10 million years
3RD ORDER B (Sequence) 1-2 million years
4TH ORDER (eccentricity) 400 thousand years
5TH ORDER (eccentricity) 100 thousand years
6TH ORDER (precession) 20 thousand years
Choice of this particular hierarchy is justified by the large number of sequence stratigraphic studies documenting the existence of the two "third order" natural groupings and by the growing number of studies confirming the presence of Milankovitch cyclicity throughout the stratigraphic record.

A4: PAC Stratigraphy of the Helderberg Group

STOP 1. Thacher Park
This locality has been selected to illustrate the fundamental, 6th order, meter-scale, allogenic cycle. This cycle is thought to be produced by the 20 ky, precessional Milankovitch signal. At this locality these rock cycles range from less than one meter to almost three meters in thickness. Some of them are totally subtidal and others (e.g. PACs 9 and 12) have tidal flat facies at their tops. Cycle boundaries are placed at surfaces where deeper water facies abruptly overlie shallower water facies independent of the occurrence of specific facies. Cycles are pattern-defined and do not require the presence of tidal flat facies or any other recurrent lithology.
Five partially complete fifth order cycles are recognized at Thacher Park in the interval represented by the Rondout and Manlius Formations (PAC 3 by itself; PACs 5-6; PACs 7-9; PACs 10-12; PACs 13-14). In that fifth order cycles are thought to be the product of the 100ky eccentricity cycle this section at Thacher Park is incomplete in terms of the number of 6th order cycles within each 5th order cycle. Reasons that could explain this incompleteness include hiatus, vacuity, failure to recognize 6th order cycles and incorrectly designated 5th order boundaries. PACs 5-14 are potentially the record of a 4th order cycle, the product of the 400ky eccentricity cycle.
The final purpose of using this section is to illustrate our approach to correlation at the level of 6th order cycles. For example, distinctive widespread lithologies are introduced at the bases of two PACs in the sequence of PACs at Thacher Park. A subtidal well-sorted calcarenite appears in PAC 7 at all localities and at all localities PAC 11 is thick bedded and contains well developed stromatoporoids. These two PACs in which relatively large facies changes occur represent the response to larger deepening events in the basin. PAC 7 is the first 6th order cycle in a 5th order sequence of cycles and PAC 11 contains the deepest facies in its 5th order sequence. In summary distinctive lithologies in certain cycles, the magnitude of facies change at cycle boundaries and the sequential pattern of cycles are all keys to correlation.

STOP 2. Rondout to Coeymans
This locality illustrates a record of 6th order cycles in a different, slightly more offshore set of Manlius facies than those seen at Thacher Park. For example, PACs 9 and 12, in which high tidal-flat facies were developed at Thacher Park, are here represented by nearly all subtidal facies. Second the record of 6th order cycles associated with unconformities is more complete. PAC 2 (actually a 5th order sequence), PAC 6b and PAC 15, recognized here at Schoharie, are missing in the more onshore Thacher area. PAC 2 and 6b are missing owing to hiatus (non-deposition) at Thacher; PAC 15 is missing due to erosion (i.e. vacuity).
In addition to PAC boundaries and unconformable surfaces, the section at Schoharie contains good examples of intracycle allogenic surfaces. Whereas PAC boundary surfaces are thought to be produced by the eustatic sea-level rise forced by the precessional (20ky) cycle, intracycle allogenic surfaces are produced by the complementary sea-level fall on the precessional eustasy curve. Thus each 6th order cycle potentially may be composed of a set of sea-level highstand facies overlain abruptly by a set of lowstand facies. The surface between the two facies sets is thus an intracycle allogenic stratigraphic surface. Such surfaces are well illustrated in PACs 9, 11 and 12, in which massive ostracod bearing calcarenites sharply overlie thin bedded ribbon calcarenites.
Finally the Manlius-Coeymans boundary is an erosional unconformity. At Syracuse, 100km to the west, an additional two 6th order cycles are preserved below this erosion surface (PACs 16 and 17) while at Kingston, 100km to the southeast, PACs 14 and 15, present at Schoharie, have been removed by erosion (fig. 1). This major erosion surface is the basis for defining this surface as a third order "Vail" sequence boundary. The section from the Brayman-Cobleskill unconformity to this unconformity represents the second 3rd order B sequence in the Helderberg supersequence. The section from this surface up to the top of the Becraft Formation (seen in the next two stops) is the third 3rd order B sequence. Erosion associated with the Oriskany unconformity (last stop} removes most of a fourth 3rd order B sequence in the Schoharie area.

STOP 3A. Kalkberg to Becraft
This final stop is in three parts. The first and stratigraphically lowest part is on the north side of I-88 two miles west of STOP 2. The lower 25 feet of this exposure are equivalent to the upper half of the Hannacroix Member of the Kalkberg Formation in the Kingston-Catskill area and the upper five feet are equivalent to the lower part of the Broncks Lake Member (fig. 2) . The base of this section is 2-3 feet stratigraphically above the top of rocks exposed in the section seen at STOP 2. The section continues in the large road cut on the south side of I-88. There is a seven foot covered interval between the two exposures. The thickness of these two covered intervals can be exactly determined because the entire stratigraphic interval is continuously exposed three miles to the east in the Schoharie Quarry and all exposed cycles and bounding surfaces can be correlated between the two localities. The Becraft and Oriskany Formations are exposed at the top of the large roadcut; however a more accessible exposure of the upper Becraft and Oriskany rocks occurs in I-88 roadcuts one mile farther west.
Our purpose in looking at the stratigraphic interval between the Manlius-Coeymans unconformity and the top of the Becraft is to lay out a tentative interpretation of the hierarchic cyclic structure of a fairly complete 3rd order B sequence representing 1-2 million years of accumulation. The entire section is in subtidal shallow to deep ramp facies. It is divisible into three 4th order sequences associated with the 400ky eccentricity cycle. These sequences in turn are each divided into four 5th order cycles related to 100ky eccentricity. Examples of 6th order cycles (PACs) in these facies will be pointed out, but analysis at this level is incomplete. Analysis of 4th and 5th order cycles is based on pattern and magnitude of facies changes and depends on correlation of those patterns to other localities. In this case larger scale cycle boundaries have been correlated to the Cherry Valley area to the west and to localities at Broncks Lake, Catskill and Kingston in the Hudson Valley. In short 3rd, 4th and 5th order cycle boundaries in the Schoharie sections have been correlated with prominent surfaces in sections over 100km away.
4th Order Cycle I
This cycle begins at the Manlius-Coeymans unconformity, also a 3rd order B boundary, and ends at the 161 foot mark on the log (fig. 2). The upper boundary is a surface between massive calcarenite and chert bearing calcisiltite (near the base of the large cut on the south side of I-88. A prominent shale occurs on the surface. The same surface is found on top of the shallowest facies in the Broncks Lake Member in the Hudson Valley (e.g. 16 feet below the New Scotland at Kingston). In systems tract analysis this 4th order cycle represents the shelf margin wedge of the third order B sequence. Fourth order cycle I can be divided into four 5th order cycles:
5th Order Cycle 1 ends at 108. 5 feet on the log at the shallowest point in Coeymans facies. This surface is the Coeymans-Kalkberg Boundary at Kingston and Catskill.
5th Order Cycle 2 ends at 135 feet on the log at a surface separating coarser favositid rich calcarenites from gypidulid bearing, more argillaceous calcarenites.
5th Order Cycle 3 ends at 140 feet on the log at a surface just below a one foot thick shale interval with lime turbidite beds. This surface is the base of the Broncks Lake Member in the Hudson Valley.
5th Order Cycle 4 ends at the 4th order boundary.
4th Order Cycle II
This cycle contains the deepest facies in the third order sequence and at Schoharie its thickness is highly condensed (32 feet versus 66 feet at Kingston). The lower boundary (described above) is at 161 feet; the upper boundary, at 193 feet on the log, is the surface at the top of a six-foot-thick massive calcisiltite unit. In systems tract analysis of the third order B sequence the lower two 5th order cycles in this 4th order cycle represent the transgressive systems tract and the 5th order boundary at 181 feet would be the maximum flooding surface. Fourth order cycle II is divisible into four 5th order cycles:
5th Order Cycle 1 is 10.5 feet thick and in the lower part is characterized by several amalgamated lime turbidites with cherts. These amalgamated units are thought to represent 6th order cycles. The upper 6th order unit is represented by 2.5 feet of calcisiltites in discontinuous lenses. The top surface of this first 5th order cycle is correlated to the Kalkberg.New Scotland formational boundary in the Hudson Valley.
5th Order Cycle 2 ends at 181 feet on the log; a concentration of chert and a thick shale occur at this boundary.
5th Order Cycle 3 ends at 187 feet on the log; beds representing condensed 6th order cycles thicken up through this 5th order cycle.
5th Order Cycle 4 is the thick calcisiltite unit.
4th Order Cycle III
This is the thickest of the three 4th order sequences at Schoharie. It is 66.5 feet thick and in general a regressive sequence of 5th order cycles, beginning in deep ramp and ending in shoreface facies. This unit is equivalent to the highstand systems tract of sequence stratigraphy. The top of the cycle is placed at a surface above the coarsest calcarenite facies in the Becraft, at 271 feet on the log. This surface is also a third order B sequence boundary. The Oriskany unconformity, 8 feet above this surface, has eliminated most of the last 3rd order sequence of the Helderberg supersequence (third order A). At Kingston the upper 3 feet of the Becraft and the Alsen-Port Ewen Formations comprise this 3rd order sequence. Fourth order cycle III consists of four 5th order cycles:
5th Order cycle 1 ends at 204.5 feet on the log and is an 11.5 foot thick set of amalgamated lime turbidites.
5th Order cycle 2 ends at 218.5 feet on the log just below a 4-6 inch shale and like the cycle just below, is a 14 foot thick set of amalgamated turbidites.
5th Order Cycle 3 ends at 237 feet on the log just above a massive calcisiltite bed. Rocks above this surface are coarser and would generally be described as Becraft.
5th Order cycle 4 extends to the top of the 3rd order sequence and consists of five coarsening upward, calcarenite shallow ramp cycles and is the thickest of the 5th order cycles in the set.

STOP 3B Oriskany/Esopus
The last part of STOP 3 is one mile farther west on I-88. Here the surface between Becraft/Alsen calcarenite and fossiliferous quartz sandstone of the Oriskany represents superimposed 2nd (i.e. Sloss sequences), 3rd, 4th, 5th and 6th order boundaries. There are two 6th order cycles in the Oriskany followed by a major deepening into basinal Esopus facies.

A5: MIDDLE DEVONIAN NEAR-SHORE MARINE, COASTAL AND ALLUVIAL DEPOSITS, SCHOHARIE VALLEY, CENTRAL NY STATE
J.S. BRIDGE AND B.J. WILLIS
Binghamton, New York, 13902-6000
The purpose of this field trip is to visit five outcrops which display the diversity of rock types exposed in Schoharie Valley. These deposits record a wave-and tide-influenced deltaic shoreline where the tidal range and degree of wave influence varied in space and time. During this trip we will focus on the relative influence of wave, tidal and fluvial currents in shaping this ancient coastline and nearshore sea bed.

A5: Middle Devonian Near-shore Deposits

STOP 1: Hardenburg Falls
Description The lowest 6 meters of the exposure at Hardenburg Falls (Fig. 5) contains interbedded gray sandstones, dark-gray siltstones and shales. Lenticular-wavy bedded parts contain very-fine grained sandstone beds which fine up to mudstone. These sandstone beds are wave-ripple cross-laminated and have wave-ripple forms on their tops. Thicker sandstone beds (typically 0.1 to 0.5 meters-thick) have sharp, erosional bases overlain by intraformational shale fragments and disarticulated shelly fossils. They are fine to very-fine grained and fine upwards. Internal structures change upwards from hummocky cross-strata or planar-strata to wave-ripple cross-lamination. Tops of beds are covered with wave-ripple marks (3-D, 2-D, and interfering types). Two-dimensional wave ripples indicate SW-NE paleocurrent oscillation. Some low-angle, hummocky cross-strata with superimposed wave-ripples and abundant shell fragments show a preferred paleocurrent direction to the NE. Rarely, such relatively coarse grained, shell-rich strata contain angle of repose cross-strata with SE paleocurrents. At the base of the section, amalgamated hummocky cross-stratified beds fill N-S oriented channels up to decimeters deep and meters wide. These beds contain rounded extraformational chert and quartzite pebbles, and intraformational shale clasts within a medium sandstone matrix.
Shell accumulations include the brachiopods Spinocyrtia, Mucrospirifer, Mediospirifer, Orthospirifer, Cupularostrum, the bivalves Goniophora, Actinopteria, Palaeoneilo, and crinoid ossicles. Most of the disarticulated shell fragments lie concave down along stratification surfaces and show little evidence of breakage or abrasion of fine detail. Some shell concentrations are markedly monospecific (e.g. Cupularostrum). Small, centimeter diameter vertical burrows occur in the tops of sandstone beds.
The 5 to 6 meter thick sandstone body in the middle of this section has a sharp base which is overlain by 2 meters of planar-stratified and swaley cross-stratified, fine to medium grained sandstone. These beds contain horizons of symmetrical and asymmetrical wave ripples with shale drapes. Parting lineation indicates NNE-SSW paleocurrents and asymmetrical wave ripples indicate a NE-SW oscillation with a preferred migration to the SW. These beds are overlain by about 2 meters of trough cross-stratified sandstone. Paleocurrents arc towards the NE mainly, with the exception of a rare, oppositely directed cross-set. Wave and current ripples are superimposed on the large-scale cross-strata. One set of small-scale cross-strata indicates an easterly paleocurrent. Large-scale planar cross-strata occur above the trough cross-strata and climb up low-angle lateral-accretion surfaces; that is, inclined bedding surfaces dip to the NW (normal to the underlying trough cross-strata) and the planar cross-strata within beds dip to the SE. Vertical, meniscate burrows of varying diameter occur in this part of the sandstone body. The upper part of the sandstone body is wave-ripple laminated, very-fine grained sandstone, which contains sparse shell fragments. This is overlain by several beds of hummocky cross-stratified and wave-rippled, fine-grained sandstone with abundant shell fragments.
Interpretation Interbedded shales and sandstones containing hummocky cross-strata, planar-strata, wave-ripple cross-laminae, wave-ripple marks, and abundant shelly-fossil concentrations are interpreted as nearshore marine deposits formed below fair-weather wave base (cf. Dott and Bourgeois, l 982; Harms et al., 1982; Hunter and Clifton, 1982; Swift et al., 1983). The sandstones are generally interpreted to be formed during storms by combined wave and unidirectional currents, whereas the shales generally represent fair-weather deposits or those formed below storm wave base. Oscillatory flows are generally directed alongshore, whereas the stronger unidirectional currents represented by low-angle to angle-of-repose cross-strata are directed onshore (easterly direction). Although the shelly fossils in sandstone beds are clearly transported, their preserved detail precludes long periods or distances of transport. McGhee and Sutton (1985) believe that such shelly-fossil concentrations reflect the diversity of the indigenous infauna and epifauna (in this case typically nearshore marine), although their relative abundances do not reflect original population densities. Monospecific shell concentrations may well reflect only slightly disturbed original communities, as it is unlikely that hydraulic sorting could so perfectly separate shells of one species from other shells with similar hydrodynamic properties.
The thick sandstone body in the middle of this exposure is interpreted as deposits of a channel mouth bar associated with a tidal channel which prograded into a storm-wave dominated sea. Swaley-hummocky cross-strata, planar-strata and wave-ripples in lower beds but angle-of-repose cross-strata in upper beds, are evidence for variation in wave and unidirectional currents upwards. Lower down within the sandstone, amalgamated hummocky-swaley cross-stratified beds and wave-ripples overlain by shale drapes indicate periodic variation in combined-flow strength. Oscillatory currents associated with wave-ripples are generally to the NE and SW (alongshore). Upper beds with trough cross-strata directed alongshore (NE) to landward (E) (but rarely in the opposite direction) are most likely associated with sinuous crested dunes formed by strongly asymmetrical tidal flood currents. The SE-directed planar cross-strata may represent wave-formed swash bars or straight-crested tide formed dunes (e.g.. Hayes and Kana, 1976; Boothroyd, 1978; Fitzgerald, 1984). Superimposed wave- and current-ripples indicate periodic variation in current strength, and the presence of weak wave currents. Inclined bedding surfaces exposed near the top of the sandstone testify to lateral migration of the upper surface. The sparse fauna and low degree of bioturbation is typical of sandy deposits in coastal areas (Gould, 1970; Howard and Reineck, 1981).
Fossiliferous sandstones and mudstones above the channel mouth bar deposit indicate rapid return to marine conditions. Depositional environments at the shoreline probably depended on the position of tide-influenced channels which distributed sediment to the shoreline and near-shore areas. Avulsion of the channel from this area abruptly reduced local deposition rates, allowing the sea to transgress locally over this location.

STOP 2: Stevens Mountain Quarry
This quarry exposure is important because it provides continuous exposures from wave-dominated marine deposits to tide-dominated channel deposits. The extensive exposures also provide a better record of lateral variations than were exhibited at the last stop.
Description Much of the quarry exposure is composed of 2 to 6 meter thick, gray sandstone bodies separated vertically by mudstone dominated intervals of dark-gray shales interbedded with centimeter-to decimeter thick gray sandstone beds (Fig. 6). The lowest 4 to 5 meters exposed above the quarry floor contains decimeter-thick beds of fine-grained sandstone with some centimeter-thick shale horizons. The sandstone beds have sharp bases overlain Ln places by drifted plant remains and shale chips. Internal structures are difficult to discern because of intense bioturbation by roots and burrows. However, large-scale cross-stratification (westerly paleocurrents) occur, and tops of beds have small-scale cross-strata and wave-ripple marks. Burrows are mainly vertical, sand-filled tubes which range in diameter from 2 to 10 centimeters: some have meniscate fills.
Within the overlying 11 to 12 meters of section (Fig. 6a, meters 5 to 17) occur several sharp-based, 2 to 3 meter-thick, fine-grained sandstone bodies separated by shale-dominated intervals with thinner sandstone beds. Bases of sandstone bodies show tool marks, and are commonly lined with plant remains, shell fragments and shale chips. The sandstone bodies are composed of decimeter-to meter-thick beds containing hummocky-swaley cross-stratification and planar-stratification. Individual beds in such amalgamated sequences are recognizable by their erosional bases overlain by shell concentrations of transported brachiopods, bivalves and Tentaculites. The upper beds within these sandstones are commonly shell-rich and contain intraformational shale chips and extraformational quartz pebbles. Angle of repose cross-stratification also is common in these upper beds, normally indicating an E to NE paleocurrent orientation. Wave ripples cap most sandstone bodies. The sandstone bodies vary in thickness and sediment type laterally. This change is most dramatic in the lowermost sandstone body in this succession. To the north, the sandstone body is about 3 meters thick and contains mainly large-scale cross-stratification and planar-stratification, indicating a range of paleocurrent directions (Fig. 6a, meter 5-8). To the south, this body thins to about 2 meters and contains mainly swaley cross-strata (Fig. 6b, meter 6 to 8). Shale-rich zones in the sequence contain decimeter-thick hummocky cross-stratified sandstone beds with wave-rippled tops. Load casts occur in distinct, laterally extensive horizons, particularly immediately beneath sandstone bodies.
The next beds contain 4 to 5 meters of interbedded shale and sandstone (Fig. 6a, meters 17.22). The lowermost decimeter-thick sandstone beds in this sequence (immediately above a sandstone body) are markedly lenticular, and rich in shells, intraformational breccia and extraformational quartzite pebbles. They contain hummocky cross-strata and, in places, angle of repose cross-strata with easterly paleocurrents. Wave ripple marks cap these sandstone beds. Most of the remainder of this interval is wavy and lenticular bedded, with very-fine grained sandstone occurring in centimeter-thick, wave-rippled beds. In the north end of the quarry, these lenticular-wavy beds coarsen and thicken upwards to decimeter-thick, hummocky cross-stratified, very-fine grained sandstone beds with wave-rippled tops, and to amalgamated hummocky cross-stratified, fine grained sandstone beds with abundant plant remains and intraformational breccia.
These beds are sharply overlain by a 5 to 6 meter-thick fine to medium grained sandstone body (Fig. 6a, meters 23 to 28). It is dominated by large-scale trough cross-stratification (NW paleocurrent), with the exception of planar stratified beds above the erosional base and some small-scale cross-strata in the finer beds near the top. The top most decimeter-thick beds have abundant drifted plant remains, shells, intraformational shale and extraformational pebbles in their bases. Paleocurrents in these upper beds are to the SE. Large vertical meniscate burrows (5-10 centimeter diameter) occur in the lower parts of the sandstone body, but smaller (1-2 centimeter diameter) vertical burrows occur in the upper most beds. In the south end of the quarry this sandstone body is thinner (Fig. 6b, meters 19 to 23). Lower parts of the sandstone body are replaced by amalgamated swaley cross-stratified, fine grained sandstone beds, and the upper two meters are replaced by hummocky cross-stratified sandstone beds with wave-rippled lops and shale interbeds. Underlying beds are finer grained than to the north. The basal erosion surface contains flutes (E paleocurrent) and grooves, and is overlain by bivalve and brachiopod shells and plant remains. Paleocurrents in the central, coarsest part of the sandstone body are to the east.
Approximately 4 meters of interbedded sandstone and shale overlie this sandstone body (Fig. 6a, meters 29 to 33). The sequence is mainly wavy-lenticular bedded with centimeter-thick wave-rippled, very-fine grained sandstone beds. Within this succession to the south is a 0.9 meter-thick, hummocky cross-stratified sandstone bed with an erosional base and wave-rippled top (fig. 6b, meter 18). It occurs at the top of a coarsening/bed-thickening upward sequence. To the north, this bed changes laterally to a 1.3 meter-thick, fine to very-fine sandstone bed with large-scale cross-strata at the base (westerly paleocurrent) and small-scale cross-strata at the top (Fig. 6a, meter 31 to 32). This bed is in turn cut out laterally by a fine-grained channel fill. At the top of this sequence, immediately below the top most sandstone body, is an extensive zone of load casts. The top most sandstone body in the quarry is approximately 6 meters thick (Fig, 6a, meters 33 to 39). The erosional base is overlain by intraformational breccia (shale blocks up to decimeters across) with brachiopod and bivalve shells in a medium sandstone matrix. The sandstone body is medium to fine grained and fines upwards in places. It is mainly large-scale trough cross-stratified, with some lenses of planar-stratification. Reactivation surfaces in the cross-strata of the lower part of the sandstone body are mainly erosional. Between laterally adjacent reactivation surfaces, cross-strata vary in dip. In places oppositely directed, asymmetrical ripple marks are preserved on foresets and reactivation surfaces, and shale drapes may also occur. Large vertical meniscate burrows also occur in these lower beds. Paleocurrents associated with large-scale cross-strata are towards the WNW in the lower half of the sandstone body, but towards the ESE in the upper half. Low angle, lateral-accretion surfaces extend through the sandstone body, and a sandstone filled channel cuts through the upper one third.
Interpretation The sandstone body at the top of this exposure is interpreted as the deposits of a laterally-migrating tidal channel (see also Johnson and Friedman, 1969). River channels preserved in coeval Catskill facies to the east have generally north-westerly paleocurrents, but range from northerly to southerly (Willis and Bridge, 1988). Therefore paleocurrents with a westerly component are in the tidal ebb and river flow direction, whereas those with an easterly component are in the tidal flood direction. Variation in ebb paleocurrent orientation in various examples of this type of sandstone body suggest that channels had a range of orientations due to local channel curvature and/or a distributive channel pattern. Dominance of ebb-directed paleocurrents lower in the sandstone bodies, with flood currents and channel fills in upper parts is typical of the strongly asymmetrical tidal currents in tidal inlets, estuaries, and tide-influenced deltaic distributaries.
Variable dip angles of large-scale cross-strata, erosional reactivation surfaces and superimposed current ripples are further evidence of strong tidal-current asymmetry. They indicate growth of sinuous-crested dunes to 'full vortex' stage during the dominant tidal current, slackening of the current and modification of dune geometry, then erosion of the dune by the subordinate tide. Such features are commonly reported from mesotidal and macrotidal estuaries (e.g. Terwindt, 1981; Boersma and Terwindt, 1981; Dalrymple, 1984; DeMowbray and Visser, 1984). General absence of tidal bundle sequences and rarity of current ripples on reactivation surfaces suggests an erosional or nondepositional subordinate flood-tidal current and a dominant ebb-tidal current that may be reinforced by a fluvial current. Bioturbation is characteristically rare in such coastal sandstone bodies (e.g. Howard and others, 1975). Large, vertical meniscate burrows are similar to those reported in fluvial and coastal channel deposits elsewhere (Thorns and Berg, 1985; Miller, 1979; Bridge, Gordon and Titus, 1986) and may be due to upward escape of bivalves. Brachiopod-bivalve fauna sparsely distributed through the sandstone bodies is also typical of nearshore communities (McGhee and Sutton, 1985; Sutton and McGhee 1985).
Sandstone bodies just below this top most sandstone body, with swaley-hummocky cross-strata, planar-strata and wave-ripples in lower parts, but angle-of-repose cross-strata in upper parts, are comparable to the sandstone body exposed in Hardenburg Falls (Stop 1). They are also interpreted to record evidence for combined wave and unidirectional currents of varying importance and intensity. Detailed interpretation of these deposits hinges critically on their lateral transition to thicker sandstone bodies dominated by angle-of-repose cross-strata and thinner sandstone bodies dominated by amalgamated hummocky-swaley cross-strata. It is also important that their bases are sharp in many places, but in others they occur at the top of coarsening-upward sequences with interbedded hummocky cross-stratified sandstones and shales immediately beneath. Furthermore, any evidence of channel fills or lateral-accretion bedding is restricted to their upper parts. These features suggest deposition on channel mouth bars which were prograding rapidly into a marine, storm-wave-dominated area. Such bars may be on the seaward side of tidal inlets (i.e. ebb-tidal deltas) associated with estuaries or barrier-beach shorelines, or associated with tide-influenced deltaic distributaries. Landward-directed (E, NE) trough cross-strata are most likely associated with sinuous crested dunes formed by strongly-asymmetrical tidal flood currents. Sets of planar cross-strata migrating to the NE, E or SE may represent wave formed swash bars or straight-crested tide-formed dunes (e.g. Hayes and Kana, 1976; Boothroyd, 1978; Fitzgerald, 1984). Wave and current ripples on dune/bar slipfaces and troughs indicate periods of tidal slack water and decreased tidal current strength, respectively. Sparse fauna and low degree of bioturbation (but dominance of the Skolithos ichnofacies) is typical of sandy deposits in coastal areas (Gould, 1970; Howard and Reineck, 1981).
Similar sandstone bodies in somewhat younger Frasnian rocks in the Binghamton (NY) region were also interpreted as channel mouth bar deposits by Halperin and Bridge (1988). However, similar sequences reported from the Cretaceous Western Interior Seaway have been interpreted as due to deposition on prograding strandplains cut by estuaries (McCrory and Walker, 1986). McCrory and Walker (1986) and Hamblin and Walker (1979) interpreted amalgamated swaley-hummocky cross.stratified beds as beach and shoreface deposits, even though they rest sharply on interbedded hummocky cross-stratified sandstones and shale interpreted as offshore storm-dominated deposits. They interpreted this sharp contact as due to rapid progradation of the shoreface. Similar sandstone bodies occurring at the tops of gradational coarsening upward sequences have been interpreted as due to progradation of a wave-dominated deltaic shoreline (Chan and Dott, 1986; Swift et al, 1987). Swift et al.(1987) interpreted the amalgamated hummocky cross-strata as middle shoreface deposits, and angle-of-repose cross-strata as deposits on the upper shoreface by combined currents with an alongshore unidirectional component. A beach face origin for the sandstone bodies studied here is considered unlikely because of a lack of characteristic seaward-dipping planar-laminae with heavy mineral layers; alongshore directed cross-strata overlain by landward-directed cross-strata and planar-strata typical of ridge and runnel systems; and eolian cross-strata. The sharp base to many (but not all) of the sandstone bodies is hard to explain by rapid progradation of a beach face, but may be readily explained by rapid progradation of a storm-wave modified channel mouth bar which formed rapidly as a result of a channel diversion. Coleman and Prior (1982) show examples of distributary mouth bar sands that lie abruptly on offshore silts, and state that bases of sandstone bodies become sharper closer to the distributary channel.
Relatively thin sandstone bodies dominated by amalgamated swaley-hummocky cross-stratified beds are interpreted as more distal parts of channel mouth bars, which are completely dominated by storm waves (combined currents). The lack of mud suggests deposition above fair weather wave base. The common occurrence of load casts near their bases suggests rapid deposition of sand on mud. Such soft-sediment deformation features are common offshore from Mississippi delta distributaries (e.g. Coleman and Prior, 1982). Paleocurrent indicators in the base of the sandstone bodies suggest a dominantly offshore directed unidirectional current, as is common in similar Frasnian rocks in the Catskill region (Craft and Bridge, 1987; Halperin and Bridge, 1988). Lenticular sandstone beds on top of these sandstone bodies, with abundant shelly fossils, intraformational breccia, extraformational pebbles, and local channelling, are evidence of relatively strong unidirectional currents directed to the east and southeast (i.e. shoreward) superimposed upon wave currents. As there is no evidence of offshore directed currents, the unidirectional currents are not considered to be tidal flood currents but rather storm-wave associated currents. As these sandstone bodies are sharply overlain by interbedded sandstones and shales interpreted as deeper water nearshore deposits, these uppermost shelly sandstone beds are apparently associated with rapid abandonment of the channel mouth bar and reduction in sand supply. Johnson and Friedman (1969) interpreted these sandstone bodies as nearshore subtidal bar deposits, and Miller and Woodrow (in press) assigned an estuary mouth shoal origin.
Similar sandstone bodies elsewhere have been interpreted as wave-formed offshore bars or shoals (e.g. De Raaf et al, 1977; Cotter, 1985). Wright and Walker (1981) have interpreted thin pebble layers at the tops of such sequences as transported by density currents. This is considered unlikely here. If such sandstone bodies do represent distal parts of storm-wave modified channel mouth bars, then their occurrence within sequences of deeper water sandstone and shales indicates channel switching (see also Swift et al, 1987). The overall sequence at Stevens Mountain Quarry indicates sandstone body deposition in progressively more landward parts of the channel-mouth bar complexes. Thus, this is an overall regressive sequence with superimposed variations in deposition related to local channel avulsion.
As implied above, interbedded shales and sandstones with hummocky cross-strata, planar-strata, wave-ripple cross-laminae wave-ripple marks, and abundant shelly-fossil concentrations are interpreted as nearshore storm-dominated marine deposits. These are interpreted in a similar way to those exposed within Hardenberg Falls (Stop 1). Sandstone beds near the base of the quarry were deposited mainly by N-NW directed unidirectional currents moving sand as dunes. Wave ripples in the upper parts of sandstone beds indicate deposition in standing water with weak wave currents. These characteristics, plus the abundance of burrows and roots, and the absence of marine fossils, suggest deposition by fluvial or ebb-tidal currents on a near coastal plain.

STOP 3: Manorkill Falls, Schoharie Reservoir
Description Most of this section is composed of gray sandstone interbedded with red, green and gray siltstone and mudstone (Fig. 7). The lower part of this section contains two 10 meter-scale fining upward sequences (Fig. 7, meters 1 to 24). The lower 4 meter-thick interval within the first sequence has a high proportion of sandstone which sharply overlies intensely disrupted mudstones. These sandstone beds generally thin and fine upwards. Individual sandstone beds are sharp-based, sheetlike to lenticular, and centimeters to a meter thick. Thinner sandstones are very-fine grained, and small-scale cross-stratified with associated current ripples or (mainly) wave ripples. Thicker sandstone beds are mainly fine grained, and contain large-scale trough cross-strata, planar-strata, or (unusually) hummocky cross-strata passing upwards to small-scale cross-strata and associated current or wave ripples. Some thicker sandstone beds lower in the sequence show low-angle (<10°) inclined bedding surfaces extending throughout most of the thickness of the bed which dip in the direction the bed thins (i.e. to the east). Upper parts of these inclined surfaces are covered with straight crested and interfering wave-ripple marks, indicating oscillatory paleocurrents NE-SW and E-W. Oscillatory paleocurrent directions are quite variable throughout the sequence; however, a NE-SW orientation is common. Large-and small-scale cross-strata and current ripples consistently indicate an easterly paleocurrent.
Sandstone beds contain vertical burrows (including Skolithos), which range in diameter from a few millimeters to 7 centimeters; larger ones commonly showing meniscus structure. Horizontal meniscate burrows occur in places in the tops of sandstone beds. Arenicolites burrows also occur. Drifted plant remains are common in sandstones, and root casts occur in the top of some sandstone beds. There are two important occurrences of tree-trunk casts. Shelly fossils are rare. One shell-rich layer near the base of the section occurs near the top of a hummocky cross-stratified sandstone bed. This layer contains bivalves, brachiopods (e.g. Spinocyrtia, Allanella tullius) juvenile crinoid fragments and bryozoa. Fish fragments are found in places.
Mudstones are either relatively unbioturbated and fissile, or bioturbated with abundant rootcasts, small vertical and horizontal burrows, and desiccation cracks. A nodular carbonate bed occurs near the top of the first sequence where calcareous rhizoconcretions are particularly abundant. This bed is similar to the one occurring at the New York City Water intake building.
The base of the second fining upward sequence is another sandstone-dominant interval (about 3 meters-thick), in this case dominated by large-and small-scale cross-strata (Fig. 7, meter 16 to 19). This interval is in turn overlain by an interval of overlapping channel fills. These channels are oriented E-W and are filled with alternating mudstone and sandstone beds. The sandstone beds are dominated by wave-ripple lamination, with rare planar and hummocky strata. Mudstones occurring adjacent to and above these channel fills are highly disrupted by mudcracks, burrows, rootcasts and in one location a tree trunk cast.
The sandstone body at the top of this section is similar to those occurring near the top of Stevens Mountain Quarry and the lower Grand Gorge route 30 section, and shows lateral-accretion surfaces. Paleocurrents near the base of the sandstone body are NW-SE.
Interpretation In the Manorkill Falls section, desiccated, bioturbated siltstones with abundant root casts, rare tree trunk casts, and horizons of calcareous concretions, clearly represent flood basins with a well developed flora which were periodically exposed and subjected to soil-forming processes. Sandstone beds overlying such deposits near the base of the section are distinctive and show evidence of easterly progradation of wedges of sand into at least temporarily standing water in which wave currents were active. The lowest bed buried and preserved the trunk casts. Two origins for this bed are considered possible: (1) a fluvial overbank sand splay, or (2) a back barrier washover deposit. Paleocurrent evidence supports the storm washover origin and deposits show many features in common with modern examples (e.g. Schwartz, 1982). However, there is little evidence in these rocks of the presence of beaches, so barrier islands seem unlikely. Although lateral migration of tidal inlets or other types of coastal channels may have removed the evidence of beaches, an overbank sand splay from a major channel is probably the most viable explanation.
Associated with the sandstone-dominated interval near the base of the section are sandstone beds showing evidence of strong wave currents, containing marine shelly fauna, and with a diverse assemblage of burrowing organisms. These deposits testify to the close proximity of the sea, and the onshore transport of marine fossils by storm waves. Furthermore, the overlying fissile siltstones with isolated hummocky cross stratified and wave-rippled sandstone beds indicate deposition of mud in quiet, standing water which was periodically agitated by waves. All of this evidence together suggest an upward transition from fluvial floodbasin/lacustrine conditions to a brackish interdistributary bay with access to fully marine waters.
A return to subaerial floodbasin conditions is signaled by desiccated mudstones with root casts, rhizoconcretions, fish fragments and a nodular carbonate-rich horizon (beds directly under the bridge; Fig. 7, meters 15-16). The overlying sandstone beds at the base of the second 10 meter-scale sequence record periodic deposition by temporally-waning unidirectional currents, probably associated with river floods. Desiccation cracks in the siltstones capping these sandstone beds and the lack of wave ripples, suggests subaerial exposure immediately following deposition. This sequence of interbedded sandstones and siltstones is interpreted as a crevasse-splay complex, but it is hard to dismiss flood tidal currents (storm enhanced?) as a depositional agent in view of the overall coastal setting.
The overlying sequence of interbedded sandstones and shales also has features indicative of mud deposition in an area of shallow water (but with periodic subaerial exposure) in which weak wave currents periodically deposited sand, and transported marine fossils into the area. The east-west oriented channel in this part of the section were apparently filled mainly by weak wave currents. The lack of evidence of reversing unidirectional sedimentary structures precludes a tidal-channel origin, and suggests instead a fluvial channel cutting across a floodbasin/interdistributary bay. Indeed, deposits typical of intertidal flats in mesotidal or macrotidal settings are notably absent throughout this outcrop. The sandstone body at the top of this section is similar to others viewed at previous stops and are interpreted as a channel-mouth bar deposits. Johnson and Friedman (1969) interpreted these deposits as interfingering alluvial marsh, tidal flat and channel deposits. They are also somewhat similar to the "muddy shoreline" deposits of Walker and Harms (1971).
The 10 meter-scale sequences exposed at Manorkill Falls reflect relative sea level changes. Mudstone beds immediately below sandstone-rich intervals reflect floodplain emergence. Abrupt onset of sand deposition following fining indicates an abrupt change in depositional environment and the onset of a deepening trend. Such sequences may be related to channel switching which locally varied deposition rate at the shoreline.

STOP 4: Schoharie Creek outcrop
Description The lowermost 11 meters of interbedded sandstone and mudstone in this stream and hillside section is, with the exception of the 2 to 3 meter thick sandstone body (Fig. 8, meters 4.5 to 7), similar to the lower parts of Manorkill Falls section (Fig. 8). Centimeter-thick, very-fine grained sandstone beds are mainly wave-rippled, whereas the decimeter-thick, fine-grained sandstone beds may also contain large-scale cross-strata (paleocurrents to N), planar-strata, and hummocky cross-strata. Tops of sandstone beds are normally wave-rippled and bioturbated by root casts and/or vertical, horizontal and U-shaped burrows of various sizes (millimeters to centimeters in diameter). Gray siltstones are bioturbated by roots and small burrows, and desiccation cracks are common. Calcareous concretions occur locally, and buff calcareous shale commonly fills desiccation cracks. There are several carbonate-rich mudstone beds near the top of this interval, in one case associated with pseudo-anticlines. Some siltstones are relatively undisturbed and fissile.
The 2 to 3 meter thick, fine-grained sandstone body near the base of the section is somewhat unusual. It is dominantly large-scale trough cross-stratified, with some large-scale planar cross-strata and planar-strata. Large-scale cross-strata indicate paleocurrents to NNW and in a generally easterly direction. Wave- and current-ripples occur on reactivation surfaces, the current-ripples oriented in the opposite direction to the adjacent large-scale cross-strata. Ripple-marked surfaces throughout the sandstone body show vertical and horizontal meniscate burrows of various sizes centimeters in diameter.
Above poorly exposed sandstone bodies between meters 11 and 19 (Fig. 8) there occurs a 3 meter thick interval of sandstone and mudstone beds that are similar to those lower down. Above this interval is approximately 12 meters of section dominated by decimeter-thick fine to very-fine grained sandstone beds, with only small amounts of gray mudstone. Sandstone beds have erosional bases and are mainly large--scale cross--stratified, with minor amounts of planar and low-angle cross-strata. Upper parts of the beds are commonly wave-ripple laminated, with wave rippled tops. Paleocurrents from large-scale cross-strata are mainly to the NNW, but some are to the SE. Beds are intensely bioturbated with vertical and U-shaped burrows. A tree trunk cast occurs near the top of the sequence.
Interpretation The lower part of the Schoharie Creek outcrop (Fig. 8, meters 1 to 11) is interpreted in a similar way to deposits exposed in the Manorkill Falls outcrop; that is, fine grained deposition in semi-permanent, near-coastal lakes or bays, with periodic emergence, plant growth and soil formation. Sand was introduced by unidirectional and/or wave currents and reworked by waves. Although trace fossils are abundant and diverse, marine shelly fossils are notably absent.
Evidence for strong tidal currents is generally lacking, with the exception of the 2 to 3 meter thick sandstone body near the base of the section. In this sandstone body bimodal paleocurrent directions in large-scale cross-strata, and wave-and current-ripples on reactivation surfaces all indicate deposition by tidal currents. However, the topmost part of the sandstone body shows more wave influence. Its stratigraphic position between coastal bay or floodbasin deposits suggests deposition in a flood-tidal delta and/or tidal channel (c.f. Boothroyd, 1978). Wave-rippled and extensively bioturbated sandstones lower down in the section along Schoharie Creek are probably sandy tidal-flat deposits.
Sandstone beds in the upper 12 meters of section (Fig. 8) were deposited mainly by N-NW directed unidirectional currents moving sand as dunes. Wave-ripples in upper parts of many sandstone beds indicate deposition in standing water with weak wave currents. Stronger wave currents are indicated by swaley cross-strata near the base of some sandstone beds. These characteristics, plus the abundance of burrowing, lack of roots (except at the top of the section), and absence of marine fauna, suggests deposition by fluvial sheet-floods in a coastal body of standing water. Despite rare southeasterly paleocurrents, there is little evidence to suggest tidal currents. Johnson and Friedman (1969) assigned these rocks to the boundary between tidal and alluvial facies.

STOP 5: Grand Gorge Route 30
Description The lowermost 28 meters of this section (Fig. 9) is closely comparable to the upper 30 meters or so of Stevens Mountain Quarry. In particular, sandstone bodies increase in thickness upwards and contain more angle-of-repose cross-strata relative to swaley cross-strata and planar-strata. There arc also lateral transitions within the lower parts of the upper two sandstone bodies between angle-of-repose cross-strata, swaley cross-strata and planar-strata. Large-scale cross-strata in the upper parts of sandstone bodies indicate paleocurrents to the NNE and NE, whereas those lower down indicate S to SSW paleocurrents. However, solitary sets of planar cross-strata within the planar/swaley parts of these sandstone bodies indicated paleocurrents ranging from NNE to SE. Oscillatory current directions are commonly NW-SE. Large (5-10 centimeter-diameter) vertical meniscate burrows occur commonly in sandstone bodies, along with millimeter-wide Skolithos, Arenicolites and Chondrites. Load casts occur beneath sandstone bodies low in the section. Beds at the base of the section contain marine fossils.
Further up section, above a 25-26 meter covered interval, a 17 meter-thick sequence of red mudstones and red-gray very-fine to fine-grained sandstones are exposed (Fig. 9, meters 53 to 70). Mudstones are either fissile, or intensely disrupted and blocky-weathering with slickensided clay-lined surfaces between blocks. Desiccation cracks are common. Horizons of calcareous concretions (rhizoconcretions) occur rarely, as do pseudo-anticlines. Bioturbation is pervasive and includes root casts and vertical burrows. One burrow type is 1-2 centimeters in diameter and has a meniscate fill. Others are 3 to 5 millimeters in diameter. The sandstone beds are sheetlike to lenticular, and range in thickness from centimeters to decimeters. Thinner beds are small-scale cross-stratified and have wave- or current-rippled tops. Thicker beds may be dominantly small-scale cross-stratified but can have large-scale cross-strata or planar-strata immediately above their erosional base. Sparse paleocurrent data indicate flow to the N or SSW. Large vertical, meniscate burrows (centimeters in diameter) occur in these sandstones but bioturbation is dominated by smaller burrows (1 centimeter diameter). Upper parts of sandstone beds may have root casts and rare calcareous concretions. Meter-thick upward fining and coarsening sequences occur in places (e.g. Fig. 9, meters 58 to 60).
The upper part of the Grand Gorge road cut contains two erosional-based, fine-to medium-grained sandstone bodies. The lower one is dominated by low-angle cross-strata and planar-strata, but also contains angle of repose cross-strata. Along erosion surfaces occur drifted plant remains and a rare occurrence of the nonmarine bivalve Archanodon (internal mold, transported). The upper sandstone body shows lateral-accretion bedding passing laterally into a channel fill. Paleocurrents lower in the sandstone body are to the south. Vertical burrows of varying diameter occur in these lower parts.
Interpretation The lower succession exposed along route 30 is comparable to the top of Stevens Mountain quarry, and is interpreted similarly. Red beds in the middle of the Grand Gorge Route 30 roadcut indicate a fluvial overbank sequence (sec also Miller and Woodrow, in press). Desiccated, bioturbated mudstones represent floodbasin deposits. Blocky weathering mudstones with local calcareous concretions and pseudo-anticlines indicate repeated welting and drying, illuviation, and formation of ped structure typical of calcareous vertisols. Fissile mudstones indicate relatively minor influence of bioturbation and repeated exposure, and may represent relatively high deposition rates in perennially ponded areas. Wave-rippled sandstone lenses indicate periodic wave activity on such ponded areas. Sandstone beds with unidirectional sedimentary structures indicate periodic sand deposition during floods, either as individual sheet flood deposits within the floodbasin, or associated with progradation of levees or crevasse splays. The coarsening-upward sequence at meters 58 to 60 (Fig. 9) suggests progradation of a levee or crevasse splay into a floodbasin. Calcareous concretions and pseudo-anticlines in overlying beds indicated subsequent rapid abandonment, reduction in deposition rate, and soil formation. The overall vertical sequence at Grand Gorge, Route 30 therefore is generally regressive, representing an upward transition from nearshore marine through coastal and fluvial deposits.

A6: INTERACTION BETWEEN KARST AND GLACIATION IN THE HELDERBERG PLATEAU, SCHOHARIE AND ALBANY COUNTIES, NY
ARTHUR N. PALMER
PAUL A. RUBIN
Environmental Sciences Division
Oak Ridge National Laboratory
MARGARET V. PALMER
R. D. 4, Box 82
Oneonta, NY 13820
Karst topography is well developed in a narrow band along the Helderberg Escarpment in Schoharie and Albany Counties, New York, where highly soluble Silurian and Devonian carbonate rocks are exposed. This is one of the finest examples of glaciated karst in the country. The purpose of this field trip is to examine some of the major karst features of the region and to show how they have interacted with Wisconsinan glaciation.
Karst features, particularly solutional caves, preserve the record of past groundwater flow patterns and geologic events very clearly -- much more so than surface topography, whose relict features tend to be easily destroyed or buried. Deposits in caves can also be dated radiometrically or paleomagnetically. Paleontological studies are beginning to show the colonization history of certain species, some of which are now extinct. Karst features may therefore aid in unraveling the complex glacial history of the area. Conversely, a knowledge of the glacial history helps to explain certain unusual aspects of the Helderberg karst. Several open-ended questions will be posed on the field trip, and participants are encouraged to contribute to the discussion.
Four sites will be visited on this field trip: from west to east these are (1) the Cobleskill Plateau, (2) Barton Hill, (3) the Knox area, and (4) the Clarksville area. Although in general they share a common geomorphic setting, each has unique characteristics. Further details about the Helderberg karst are provided by Kastning (1975), Baker (1976), Palmer (1976), Mylroie (1977), Mylroie and Palmer (1977), Palmer et al. (1991), and Rubin (199Ia, 1991b).

A6: INTERACTION BETWEEN KARST AND GLACIATION IN THE HELDERBERG PLATEAU, SCHOHARIE AND ALBANY COUNTIES, NY

STOP 1. View of the Cobleskill Plateau
The Cobleskill Plateau contains the largest karst drainage systems in the Northeast, of which the tourist caves Howe Caverns and Secret Caverns are part. A general view of the plateau is seen at Stop 1. The low, broad plateau consists mainly of limestones of the Helderberg Group, overlain in places by younger strata and by glacial till. The beds dip an average of 1.5 degrees to the SSW toward the entrenched valley of Cobleskill Creek, into which most of the karst systems drain. The bedrock floor of the valley is buried beneath as much as 30 m of late Quaternary glacial/alluvial sediment. The creek now follows a route slightly different from its deep-stage pattern, and in places it has migrated laterally onto exposed bedrock that once flanked the valley. Where the creek crosses the Coeymans Limestone (Helderberg Group), much or all of its flow is lost to underground solution conduits and emerges nearly a kilometer downstream. The present course of the creek is postglacial, so the diversion conduits have apparently developed within the past 14,000-15,000 years. The conduits are well adjusted to the present flow pattern, so it is doubtful that they are reactivated older features.

Cross bridge over partially dry bed of Cobleskill Creek.
During low flow the entire creek flows underground for
about a kilometer

STOP 2. Doc Shaul's Spring
Doc Shaul's Spring, at junction with road to right. The spring is on the left, on private property, and is visible from the road.
Many karst springs are located in the exposed limestones at the eastern end of the plateau around Howe Caverns. Farther west, however, the erosionally truncated limestones have been covered by valley sediment. Doc Shaul's Spring, the main outlet for water in the western part of the plateau, rises upward from the limestone subcrop through a conical pit in the overlying sediment.
The original spring appears to have issued directly from the exposed down-dip edge of the limestone prior to aggradation. The depth to the original spring level has not yet been determined. Divers have found the opening to be nearly choked with logs and sediment. Did the valley sediment accumulate slowly enough that it was continually swept away by the up-welling water, so that the spring remained open? Or was the spring inactive during aggradation and reactivated only by water forcing its way upward through the sediment? In McFail's Cave, which feeds the spring, calcite deposits show evidence for re-solution as much as 25 m above the present spring level, indicating prolonged or frequent flooding to that height. Saturated sediment has an effective specific gravity of about 1.1 (accounting for buoyancy and porosity), so this pressure head could have balanced the weight of about 23 m of sediment.

Drumlins and glacially deranged drainage.
In this area the latest movement of glacial ice was west-southwest,
owing to deflection by the Helderberg Escarpment.

Road makes abrupt detour around the nose of a drumlin.
The drumlins in this area are superposed over a north-south preglacial valley in the Helderberg limestones, now almost entirely filled with glacial till.

"Drumlin Sheep Farm" on right.
Continue straight past road to left. (Road to left goes up crest of drumlin, providing a good view of the surrounding terrain.)

STOP 3. Brown's Depression
This huge closed depression, which contains a second-order sinking stream, looks like a large sinkhole. In reality it is an unfilled or exhumed remnant of the north-south bedrock valley filled elsewhere by glacial till. The depression is on private property.
Surface drainage was deranged by glaciation in many parts of the Cobleskill Plateau. Prior to glaciation a prominent north-south stream valley extended through the western part of the plateau, reaching downward through almost the entire Helderberg Group in places. Deflection of glacial ice by the Helderberg Escarpment imposed a local west-southwest movement of glacial ice. As this direction was nearly perpendicular to the valley, the valley was almost completely filled with glacial till. As a final flourish, the ice camouflaged the valley with transverse drumlins that stand well above the surrounding terrain. Surface streams now follow a circuitous route around the drumlins, losing themselves here and there in swamps.
The buried valley, shown in Figure 4, was detected with gravity surveys, refraction seismology, and well logs by Palmer (1976) and with reflection seismology by Mylroie (1977). Its average depth of fill is 60-70 m.
Brown's Depression appears to be an enormous sinkhole but is in fact an unfilled part of the preglacial valley. A second-order stream sinks into the limestone at the western edge of the depression. Either this part of the valley was never filled by glacial sediment or it was later exhumed by sapping through underground conduits. Laminated clays in the bottom of the depression at an altitude of 1100 ft (335 m) are probably deposits from glacial Lake Schoharie, in which case the depression was present during the last glacial retreat (Mylroie, 1977).

Another view of Brown's Depression on the right.

Cross the valley draining into Brown's Depression.

Barrack Zourie
Barrack Zourie, an outlier of Middle Devonian strata, is
visible on the right

Shale pit in the Esopus Formation on right.

STOP 4. Sinkholes and Shafts above McFail's Cave
Pull off road into grassy parking lot on left. Various sinkholes, shafts, and sinking streams can be viewed along the path that leads from the far end of the parking lot. Permission to visit the property must be obtained from the National Speleological Society, which owns the woods in which the karst features are located. The local address is c/o Emily Mobley, Box 10, Schoharie, NY 12157. Please do not cross the field, as it is private cultivated land.
Sinkholes are clustered in areas of the Cobleskill Plateau where groundwater recharge is most abundant. Stop 4 is located in a relatively low part of the plateau where the lower Kalkberg and Coeymans Limestones are exposed and is surrounded by higher areas of relatively impermeable overlying strata. Deep shafts, sinkholes, and sinking streams are well developed here. Their origin is mainly solutional, although some enlargement has taken place by erosion and subsidence of overburden and bedrock blocks. The effect of prominent vertical joints (with strikes of N 22° E and S 70° E) is clearly shown by the linearity of the shafts. These recharge points feed underlying McFail's Cave, which contains about 10 km of accessible passages. The property is owned by the National Speleological Society (see address in Road Log for access permission). The cave is closed to visitors, but similar features can be seen in Howe Caverns, which is open to the public.
The main part of McFail's cave consists of a long sinuous canyon passage that descends from the recharge area in the direction of the stratal dip. It intersects a low-gradient tributary tube that follows roughly along the strike of a low-angle thrust fault of northeasterly dip. It appears that the tube was once the upstream part of the main passage of Howe Caverns to the southeast, but late Pleistocene collapse and sediment fill have blocked the connection. The McFail's Cave water now follows an irregular diversion passage southwestward to Doc Shaul's Spring.
Many of the inactive passages in the cave are blocked by gravel, sand, and clay. Even the active stream passages show evidence of having been nearly filled with sediment at one time. The position and character of the sediments are well out of adjustment with the present flow regime, which suggests that they are related to glaciation. Laminated clays occupy the very lowest levels of stream entrenchment in the main passage. They are found only in caves in the drainage basin of Schoharie Creek (including tributaries Cobleskill Creek and Fox Creek), so they were probably deposited during a phase of glacial Lake Schoharie, when groundwater was rather stagnant. Laminated clays in McFail's Cave range from 970 to 1130 ft (296.344 m) in altitude.
The geomorphic sequence thus includes (1) fluvial entrenchment of the region, exposing the limestones; (2) development of cave passages during a preglacial (or interglacial) time, when the water table stood about 20-25 m higher than today; (3) further fluvial entrenchment, causing diversion of groundwater away from Howe Caverns to Doc Shaul's Spring; (4) filling of large parts of the cave with sediment, probably during glacial advance or retreat, and probably contemporaneous with aggradation of stream valleys; (5) excavation of much of the sediment by cave streams, possibly with some enlargement of passages by glacial meltwater; (6) deposition of lake clays and thin overlying gravels and sands; and (7) postglacial erosion of clays and other sediments. Some of these stages may actually overlap in time or represent sequential phases of the same event. Does the intervention of stage 5 between stages 4 and 6 indicate multiple glaciation, or simply different phases of a single glaciation? The close relationship of the sinkholes and cave to the present topography shows that the basic morphology of the plateau is fairly ancient. The cave is adjusted to the bedrock configuration, including the deep stage of fluvial erosion, whereas the glacial features are simply superimposed.
Despite the great concentration of groundwater recharge in this area, during most of the year the water entering the cave is slightly supersaturated with dissolved carbonate from the soil and the upper part of the bedrock. Degassing of carbon dioxide from the water in the cave reduces the ability of the water to hold dissolved carbonates. It is therefore unable to enlarge the cave by solution at these times, although small amounts of abrasional enlargement may take place. Only during periods of heavy overland flow does solutionally aggressive water enter the sinkholes. Most of the present cave enlargement takes place at these times. During the early stages of cave development, before the cave became aerated, groundwater was able to penetrate through the entire plateau before becoming saturated, since it retained all the carbon dioxide it acquired from the soil. Total hardness of the cave water during low flow is now about 250 mg/liter calcium carbonate equivalent. High-flow measurements show an irregular scattering of lower solute concentrations.

STOP 5. Howe Cave Quarry
Park along the right side of the road and climb the right bank to the quarry overlook. Please be careful! There are good exposures of Manlius and Coeymans Limestones, with a low-angle thrust fault in the far wall. The downstream end of Howe Caverns is located in the residual rock peninsula projecting from the far wall of the quarry.
The Manlius and Coeymans Limestones are exposed in the wall of the Howe Cave Quarry, which was once a source for crushed rock. The Rondout Dolomite beneath the quarry floor was also mined for cement. Please watch your step so you don't slip over the edge --we have not arranged for permission to enter the quarry. The Manlius is very thin bedded, with much differential resistance, whereas the overlying Coeymans is massive and nearly uniform in character; but these differences are almost totally masked in this artificial exposure. Compare this view with that at Thacher Park (Stop 10).
The peninsula of rock projecting into the quarry contains the downstream end of Howe Caverns. This part of the cave is not open to the public. Note the trace of a low-angle thrust fault in the opposite wall of the quarry. Howe Caverns intersects the fault, and the fault's effect on the origin of the cave is described in the following section.

STOP 6. Howe Caverns
Howe Caverns, which is open to the public, contains many of the features described for McFail's Cave. A map of the cave is shown in Figure 9. A 45-meter elevator ride leads to a large tubular conduit that originally formed at or near the water table in the upper part of the Manlius Limestone, nearly parallel to the local strike. A drop in the water table caused the cave-forming water to entrench the floor as a free-surface stream, which is seen today along the tour route. Vadose tributaries enter on the up-dip side. The largest of these, now dry, is the Winding Way, a narrow canyon-like passage formed mainly by the downcutting of a free surface cave stream. Its sinuosity was initiated by small structural irregularities in the limestone and has been smoothed by stream action.
Banks of laminated clay in the main passage are apparently remnants of material deposited at the time of Glacial Lake Schoharie. Their elevation is 867-908 ft (264-277 m) above sea level. The clay is horizontally laminated, rather than parallel to the passage contours, showing that the clay beds are not simply the result of periodic flooding by the cave stream. The clay extends below the deepest level of the cave stream. In places it is interbedded with dark gray organic-rich beds 1-2 mm thick at intervals of 0.5-1.0 cm. It is uncertain whether they represent seasonal deposits, but if so, the entire sequence could represent about 1000-3000 years. Carbonate minerals comprise up to 25% of the sediment (by weight). Some of the clay bodies show remnants of a thin overlying carapace of calcitic flowstone.
The fault exposed in the Howe Cave Quarry cuts through the cave at the "Old Witch," just below the Bridal Altar. The significance of the fault to the cave origin has been debated. No passages actually follow the fault, and there has been no apparent solutional enlargement along it. However, the main passage splits into two levels where the fault intersects it. Apparently the fault was used as the guiding fracture when the cave stream began to entrench its channel and abandoned the original passage level, probably triggered by entrenchment of the Cobleskill Creek valley.

Cross Schoharie Creek.
Deep entrenchment into the Helderberg limestones by this river and its tributaries, Cobleskill and Fox Creeks, has been responsible for most of the karst development in Schoharie County.

Terrace Mountain, on the right
Terrace Mountain, on the right, shows fine exposures of
the gently dipping Manlius and Coeymans Limestones.

Barton Hill rises to the left.
Barton Hill stands in bolder relief than the Cobleskill Plateau. Fox Creek has entrenched entirely through the Helderberg limestones, leaving their down-dip edges exposed far above the valley floor. Virtually all its karst drainage is perched above base level. Many springs issue from the southern (down-dip) side of the hill, as well as along the eastern edge, where King Creek has entrenched partly through the Helderberg Group.
Most of the caves are simple down-dip conduits, which implies that the limestones were entirely exposed before significant cave development took place. As shown in Figure 10, the caves are concentrated in the upper Manlius Limestone. Prominent bedding-plane partings at that horizon were probably the initial pathways for the groundwater that formed them. The underlying limestone is relatively shaly and dolomitic, and so is less favorable for cave development. A few narrow diversion routes for water have formed in the underlying Rondout and Cobleskill at the southern edge of the plateau, but they are merely tight crawlways. They may be post-glacial, following fractures and partings opened by glacial loading and unloading, but since the limestones were exposed long before the Wisconsinsan glaciation, it is possible that they are much older.
Gage Caverns, shown in profile in Figure 10, reaches almost to the northern edge of Barton Hill. Its former catchment area was apparently much larger than at present. It is uncertain whether this is an indication of glacial modification of the drainage basin, or meltwater recharge to the cave, or simply the result of truncation of the headwaters by fluvial erosion.

STOP 7. Schoharie Caverns Spring
Entrance to Schoharie Caverns. Glacial till has partly blocked a perched karst spring. Postglacial solution channels several centimeters deep are visible in the rock face. The cave is not open to the public.
Schoharie Caverns consists mainly of a single high, narrow canyon passage about 600 m long and containing a substantial stream. Divers have recently penetrated through water-filled sections, nearly doubling this length. This is private property whose ownership has recently changed. Contact the authors for information on access policy. The cave is located mainly in the upper part of the Manlius Limestone, and its water emerges high above the Fox Creek valley. Bedrock is exposed in the floor in the upstream part of the cave but is obscured by sediment in the downstream part. Carbonate rocks extend much farther downward, and a nearby smaller spring issues from the base of the Cobleskill Limestone a full 30 m lower.
This site provides a good example, though a rather simple one, of how caves can be used to interpret the sequence of geomorphic events. Schoharie Caverns contains remnants of calcite travertine that has been deeply corroded by solution. U/Th dates for the travertine exceed 350,000 years (the limit of the technique at the time), showing that the deposits are considerably older than Wisconsinan (Stein-Erik Lauritzen, Bergen, Norway, personal communication, 1983). The cave, of course, must be older still. Because the cave is mainly a down-dip vadose canyon, it must have originated after Fox Creek had deepened its valley below the spring elevation. Corrosion of the travertine was probably caused by partial blockage of the spring by late Pleistocene glacial till, which flooded much of the cave with water. Erosion of the till, as well as artificial excavation in the late 1950s, allowed the cave to drain. A culvert was laid in the excavated trench to prevent the cave stream from being ponded by later subsidence of the till.
The limestone face on the western side of the cave entrance contains solutional rills up to a centimeter deep formed by water draining out of the overlying soil. They are clearly postglacial, but their exact age depends on when the face was exposed from beneath its till cover.

STOP 8. Calcite Cemented Glacial Deposits
Along the southeastern edge of Barton Hill is an exposure of glacial outwash cemented with calcite. The calcite was contributed by groundwater seepage from the adjacent limestone plateau. Degassing of carbon dioxide from the emerging groundwater caused supersaturation with respect to calcite.

Karst spring on left.

STOP 9. Limestone Rise (Karren Topography)
Climb onto the Helderberg limestones.
Limestone Rise, a small property owned by the Nature Conservancy, displays good examples of a bare karst "pavement" with solutionally enlarged joints in the Coeymans and Manlius Limestones. The soil is very thin and entirely absent in places. Such fissures constitute what is known as karren, an exposed form of epikarst. It is typical only of glaciated regions, which suggests either that the soil has been partly stripped off by glacial action, or that fissure enlargement has been enhanced by glaciation. Loading and unloading by glacial ice could have widened the joints and made them more susceptible to solution, perhaps by subglacial meltwater, and allowing soil to subside into the enlarging fissures.

STOP 10 Sinkhole Entrance of Knox Cave
Park on right of road, follow path about 1/4 mile to sinkhole entrance of cave
Knox Cave is owned by the Northeastern Cave Conservancy (see information in Road Log). The cave and property can be visited only by permission, which includes signing a liability waiver. Its entrance is a sinkhole caused mainly by the collapse of several high fissures and rooms. Several other sinkholes are located nearby, one of which formed rather recently, as shown by its steep, fresh walls of overburden. The cave is a nearly inactive relic consisting of a network of fissure passages superimposed on a crudely branching system of tubes and canyons. Although the entrance is clearly a collapse sinkhole, into underlying passages, it has undergone much of its enlargement by solution, subsidence, and erosion.
Knox Cave is located only about half a kilometer from the up-dip edge of the Helderberg Plateau. It appears that the present recharge area is not large enough to account for the great size of the cave and its sinkhole, in contrast with the broad area feeding the rather narrow shafts at McFail's Cave. The lack of active streams in Knox Cave (except during heavy runoff) suggests that it may be a survivor of a time when the plateau extended much farther to the north, providing a larger recharge area. On the other hand, runoff from the shaly New Scotland Formation feeds sinkholes farther west in the plateau, and perhaps the cave is now dry simply because of shifting of sink points. An intriguing possibility is that cave enlargement could have been enhanced by glacial meltwater. The network pattern of many of its passages indicates rather severe flooding, which may have required much more water than could have been provided by the existing catchment area.

Thompson's Lake is seen on the way to Stop 11.
The lake occupies a closed basin in the Onondaga with no surface outlet. Much of the water enters -- and all of it exits -- through solution conduits in the limestone. Drainage from the lake resurges at Pitcher Farm Spring about 1.5 km to the southwest. It is probable that the lake originated as much by glacial derangement of surface drainage as by karst processes.

STOP 11. Thacher Park Overlook
This is only a brief stop, mainly for the view. The salient feature of Thacher Park is a 30-m cliff of limestone and dolomite of the Rondout, Manlius, and Coeymans Formations. The Albany lowland lies more than 300 m below. Note the differential weathering that distinguishes the various beds so well, in comparison with the artificial exposure in the Howe Cave Quarry. Several cave springs occur in the Rondout Dolomite at the base of the cliff, perched on the underlying Indian Ladder Shale. Note the gentle fold in the eastern part of the cliff.

Road cuts in limestones of the Onondaga Group.

Dry bed of Onesquethaw Creek on left.
Much of the water in the basin flows underground through the Onondaga.

STOP 12. Clarksville Cave
Park behind June's Place (diner). Please do not usurp the parking places of potential customers. The cave entrance is a collapse sinkhole reached by following the trail northwest from the parking lot for about 1000 ft. The cave drains a large part of the Onondaga bench to the north, seen over the last two miles of the field trip. Enlargement of the cave was probably enhanced by subglacial meltwater, as will be shown at the next stop.
Clarksville Cave is a large cave in the Onondaga Limestone consisting mainly of a single strike-oriented passage developed along a major thrust fault and its subsidiary faults (Figure 12; Rubin, 1991b). Its cross section is larger than that of any other cave in the Onondaga Group. Minor tributaries and diversion passages complicate its pattern. The cave takes overflow from inaccessible conduits to the west that drain the bed of Onesquethaw Creek. The main cave entrance, viewed on this field trip, is a collapse sinkhole over the main passage. The entrance is on private property; anyone who wishes to visit the cave should first check with one of the authors regarding access policy, conservation, and safety.
The cave contains considerable amounts of detrital sediment ranging from silty clay to coarse gravel. The direction and velocity of past water flow are shown by scallops, which are intersecting solutional hollows in the limestone wall. Their asymmetry, like that of current ripple marks, shows the former flow direction. Their length is inversely proportional to the velocity of the water that formed them (see Curl, 1974). Scallops are abundant in nearly all caves formed by rapidly flowing water; but in places in the upstream part of the cave they indicate velocities and discharges much larger than those expected from the presently available catchment area (Rubin, 1991b). There is evidence for enlargement of the cave by glacial meltwaters. Outwash gravels a few hundred meters southeast of the cave give an additional hint of glacial meltwater activity. Multiple passage levels in the cave are not graded to each other, as might be expected if they were formed by a gradually declining water table. They appear to have formed by floodwater enlargement of the cave. Relict infeeder passages show evidence that flow was formerly available from sources that are no longer active. These ideas are clarified at the next stop.

Anticline in the Onondaga limestone.
This structure appears to be merely a shallow flexure above a large
underlying thrust fault.

STOP 13. Subglacial Meltwater Channels
The southeastward view at Stop 13 shows a broad subglacial meltwater channel that once fed Clarksville Cave. The channel today is a broad valley containing no stream and out of adjustment with nearby stream patterns. That it is a subglacial meltwater channel is verified by the presence of upstream bedrock gorges (on posted property on the other side of the road), which have total disregard for the present topography. They average about 3-5 m wide and 2-3 m deep and have a crudely braided pattern. None are active today. They cut across hill tops and lead headward to the very up-dip edge of the Onondaga escarpment. The solubility of the limestone was favorable to the origin of such channels in a short time, whereas the structural integrity of the limestone has preserved them since they were abandoned. Their pattern is compatible only with subglacial meltwater channels.
Several cave openings lie in favorable positions to have received water from these channels, but they also are relict features today. Recent exploration shows that these caves are (or once were) tributary to Clarksville Cave. Small solutional scallops give evidence for considerable discharge in the past. A large amount of meltwater must have entered Clarksville Cave, providing a greater discharge than is available under present conditions and explaining its large size and relict flow features. According to Figure 3, it is unlikely that large caves could have formed in the few thousand years that subglacial meltwater must have been active in the area; but certainly much of the cave enlargement could have taken place during this time. Meltwater is rather low in carbon dioxide content and is rarely capable of dissolving more than a few tens of mg/liter of limestone. However, the meltwater would have come in almost immediate contact with the limestone, allowing almost its entire solutional capacity to be exerted in enlarging caves. A maximum of 0.05 cm/yr of wall retreat would be expected, which translates to as much as one meter of diameter increase per 1000 years.
About 10 km to the east, in Hollyhock Hollow Sanctuary, several bedrock pedestals up to 2.5 m high and 2-2.5 m in diameter show evidence for stream scouring around their entire bases. They are located in a valley tributary to glacial Lake Albany and appear to have been formed by meltwaters in the same manner as the channels in the Clarksville area.

Marcellus-Onondaga Contact
The contact between the Marcellus Formation and the underlying Onondaga Group is clearly visible as the break in slope where the hillside of shale meets the more resistant limestones. Runoff from the hillside sinks in many places on the Onondaga bench and resurges at springs at the base of the limestone to the east.

STOP 14. Sinking Stream at Onesquethaw Cave
Unlike the other caves on the field trip, Onesquethaw Cave is fed by a large perennial sinking stream. The entrance actually receives water only during high flow, as most of the stream sinks several hundred meters upstream and emerges into the cave about midway along its length. The sinking stream is fed by a catchment area of 3.3 km , mainly on shales and sandstones of the Hamilton Group. During floods the cave can fill entirely with water. The flashiness of the runoff has a distinct effect on the character of the cave. Chert beds in the Onondaga have created constrictions in the main passage, around which floodwaters have formed anastomotic diversion routes. The cave is presently owned by Albany County and is closed to visitors. The sinking stream follows what appears to be a postglacial channel partly perched on glacial till. The cave is so well adjusted to the position and size of the stream that it seems that the entire cave could be postglacial. Furthermore, detrital sediments, so abundant in the other caves on the field trip, are very sparse. The other caves clearly pre-date the latest glacial advance. Is Onequethaw an exception?
It is possible, however, that the present sinking stream has simply reoccupied a preglacial route, reactivating a cave that is much older than it would appear. Calcite speleothems have been dated at about 20,000 years b.p. by Stein-Erik Lauritzen (personal communication, 1983). This is an odd date, because it coincides roughly with the latest Wisconsinan maximum. Perhaps conditions beneath the continental ice sheet were not as static as most researchers have assumed.

A7: HISTORY, ECONOMY, AND GEOLOGY OF THE BLUESTONE INDUSTRY IN NEW YORK STATE
James R. Albanese
Department of Earth Science
SUC Oneonta 13820
William M. Kelly
3136 CEC Albany, NY 12230
Upper Devonian sandstone units that occur in southeastern New York, known as bluestone, were a source of dimension stone for the construction industry of southern New York and eastern Pennsylvania long before their descriptions were reported in the geological literature in 1886. Various parts of the Sonyea and West Falls Groups have been quarried. However, the economic significance far outweighed the geological importance of the units, so precise relationships between the minable stone and its geologic unit or environment of deposition were and are largely unknown. The extraction of bluestone, like the exploitation of other low value per volume commodities, has been driven principally by market demand rather than by geologic availability. Descriptions of the properties of the stone are primarily cosmetic rather than petrographic.
The purpose of this trip is to demonstrate the association between the geologic and mining aspects of bluestone quarrying. It will explore the connection between the geology and the mines and examine historic and modern quarrying operations. Participants will learn of the technologies used to locate, identify, and extract currently recognized bluestone resources. In addition, changes in the style of mining and in parameters of the product that could be economically recovered throughout the history of the industry will be illustrated.
Bluestone has been historically quarried in the Hudson Valley, central and southern New York, and northern Pennsylvania and continues to be quarried in some of these areas. Bluestone, or flagstone, is the trade, or commercial name for this type of dimension stone. The rock can be generally classified as a well-cemented, angular, medium-to fine-grained sandstone with its most outstanding characteristic being the bedding. Even-bedded rock that can be split in parallel layers is marketable as bluestone, regardless of its grain size, texture, color, or composition. In general, this bedding characteristic and its resistance to wear and weathering, the result of being composed primarily of quartz, give the stone its economic value. The "blue" of the bluestone name came from the color of the stone quarried in Ulster County during the 19th century, and is no longer an accurate description. The color of bluestone varies from the more common blue and gray colorations to include green

A7: HISTORY, ECONOMY, AND GEOLOGY OF THE BLUESTONE INDUSTRY IN NEW YORK STATE

STOP 1. Good evenly bedded bluestone.
Thick-bedded (up to 20') sandstone layers interbedded with sandy shale containing sandstone rubble and intraformational breccia. Shale is red and weathers rusty. Good evenly bedded bluestone, some cross-bedding, plant fossils. Well-jointed; the main joint set is roughly N-S and the subsidiary set roughly E-W. Outcrop is 0.5 miles long along the south side of the road. More thinly, parallel-bedded and cross-bedded units can be seen on the east end of outcrop.

STOP 2. Rock suitable for bluestone
Rock suitable for bluestone with 1" bedding in 6' thick layers interbedded with shale layers up to a meter in thickness. Channel deposits composed of basal conglomerates, massive and cross-bedded sandstones, grading into parallel bedded layers at the top of each sequence. Some of the shale contains pyrite, weathering to produce the rusty coloration. Toward the east end of outcrop, very thick (30 feet) sandstone, some cross-bedded, overlying a shaley basal conglomerate, and underlying good bluestone layers. Toward the west end, a channel cut into existing cross-beds and overlain by shale overbank deposits.

STOP 3. Indian Country Bluestone Company
Prominent cross-bedding is displayed in the quarry. Note: such well-developed cross-beds are of interest only from the sedimentary structure standpoint, they are a disaster for a quarry. We will see a demonstration of bluestone splitting by old methods (by hand) and stone trimming with the guillotine. Please look over the yard to see the variety of products ready for shipping-pattern stone, tread, veneer, and crushed stone produced from the waste bluestone.

STOP 4. Thick sandstone channel with shale overbank deposits.
Note: This is a dangerous place. Stay off the septum of sandstone on the south side of the road, between old and new Routes 17. The drop on the other side is as great as the height of this outcrop. Be careful on the road because vehicles move past this blind curve at high speeds. Also, stay back from main outcrop face to avoid danger of rock falls.
Thick sandstone channel with shale overbank deposits. Stratigraphic packages consist of a breccia at the base, cross-bedded layers above, changing to planar layers near the top, typical of fluvial deposition. Some of these packages may represent a single flood deposit. The cross-bedding is at such a large scale that the rock may appear to be massive. Lateral accretion surfaces produced by channel migrations are visible on the upper surface of the outcrop on the south side of the road. Breccia layers contain shale pebbles, plant material, and concretions. Storm beds and features of soft sediment deformation are present.

STOP 5. Tompkins Bluestone Company
At this stop we will be the guests of Tompkins Bluestone, one of this area's bluestone distributors. Tompkins uses laser-guided computer-controlled 3' and 10' circular saws to cut stone to whatever dimensions the market demands. They are involved in specialty stone cutting and carving as well as the production of stone for the more traditional applications as treads, flooring, and veneer.

A8: STRATIGRAPHY AND DEPOSITIONAL ENVIRONMENTS OF THE LOWER PART OF THE MARCELLUS FORMATION (MIDDLE DEVONIAN) IN EASTERN NEW YORK STATE
DAVID H. GRIFFING
Binghamton, New York 13902-6000
CHARLES A. VER STRAETEN*
The State Education Department
Albany, New York 12230-0001
(*Present Address:
Rochester, New York 14627-1001)
The "layer cake" stratigraphy of the Hamilton Group in western and central New York appears to change into a more complex and confusing sequence towards the east, where strata thicken and are increasingly dominated by coarse grained siliciclastics. These trends are exemplified by the lower part of the Marcellus Formation. In western and central New York, this part of the Marcellus Formation is characterized by poorly fossiliferous, black shales with limestone interbeds. These limestones vary in type from intervals of barren or fossiliferous carbonate concretions to complex meter-scale packages of skeletal limestone beds that can be easily correlated over most of this region. Lateral facies changes and the dramatically increased thickness make correlation difficult in strata of the lower part of the Marcellus Formation in easternmost exposures. An approximate 13-fold increase in thickness in eastern New York is accompanied by a transition to more medium-to coarse-grained siliciclastics that overlie the initial black shale deposits. However, the distinctive faunas, sedimentary fabrics, and taphonomic indicators present in some of the strata persist through the facies transition. These strata form useful marker beds that provide a more detailed understanding of the evolution of the northern Appalachian Basin during late Eifelian time.
The purpose of this field trip is to examine the stratigraphic, sedimentologic, and taphonomic changes across the limestone-shale/coarse-grained siliciclastic transition in the lower part of the Marcellus Formation. The following report is a result of two separate ongoing studies. The first is a detailed examination of the limestone-rich facies of the Cherry Valley Member and the upper part of the Union Springs Member in western and central New York state (DHG). The second study involves regional correlation of strata in the lower part of the Marcellus Formation in eastern New York.

A8: STRATIGRAPHY AND DEPOSITIONAL ENVIRONMENTS OF THE LOWER PART OF THE MARCELLUS FORMATION (MIDDLE DEVONIAN) IN EASTERN NEW YORK STATE

Note exposures of Gilboa Fm. in roadcuts north of this intersection.

Note exposures of the Panther Mountain Fm. in small roadcut on the north side of the road.

Note outcrop of lower Hamilton Group shales on W side of the road, N of the junction.

Note roadcut of lower strata of the Marcellus Fm. on the right (south) side of the road.Placemark

STOP 1. Chestnut Street Roadcut
Park at the east end of the roadcut. Note the panorama view of the Mohawk Valley and the southern Adirondacks to the north.
This outcrop features the uppermost part of the Union Springs Member, an excellent exposure of the complete Cherry Valley Member, and the lowermost part of the Chittenango Member. Two thin zones of intensely deformed shale within the Union Springs Member and a thrust fault that ramps up through the Cherry Valley Member can be observed at this locality. Bosworth (1984a, b) associated these deformation features with northwest-directed overthrusting that occurred during either Acadian or Alleghenian orogenic events.
The exposed 4.0 m of Union Springs Member shales contain several intervals of carbonate concretions at this locality. One on these concretion intervals commonly features the goniatite Cabrieroceras pleibeforme and lies approximately 1.0 m below the base of the Cherry Valley Member. The Chestnut street Beds form one 20 cm-thick ledge of skeletal wackestones and packstones around 17 to 20 cm below the base of the Cherry Valley Member. Although the individual Chestnut Street Beds are amalgamated and burrow-mottled, distinction of the uppermost darker gray, crinoid-rich packstone bed can be made on outcrop. A thin, silty, calcareous, gray to black shale interval between the Chestnut Street Beds and the Cherry Valley Member features the goniatite Agoniatites nodiferous. The clean weathered faces of this roadcut make it one of the best places to view internal stratigraphy of the Cherry Valley Member. The 1.2 m-thick section of Cherry Valley contains a 15 to 20 cm-thick lower massive packstone bed, a 60 to 65 cm thick middle nodular packstone/marlstone interval, and a 37 to 40 cm-thick package of upper packstone beds. Concentrations of whole and partially preserved goniatites can be observed in the basal bed and upper packstone intervals. Orthocone nautiloids can also be observed in the base of the upper packstone interval, especially 30 cm below the upper contact of the Cherry Valley Member. Planolites traces are common on the bedding plane surfaces of fallen blocks of the Cherry Valley Member. Calcareous black shales with small brachiopods, dacryoconarids, and small orthocone nautiloids mark the transition from the Cherry Valley Member into the overlying sooty black shales of the Chittenango Member.

Note outcrops of Kalkberg Fm. along U.S. Rte. 20 west of Sharon Springs.

Note outcrops of Onondaga Limestone.

Union Springs Mbr. of the Marcellus Fm.
Note exposures of the Union Springs Mbr. of the Marcellus Fm. and the underlying Onondaga Limestone in the drainage ditch on the right (west) side of the road for the next 0.4 miles.

STOP 2. Mineral Springs Section.
This stop exposes the upper 4.5 meters of the Union Springs Member, a complete section of the Cherry Valley Member (1.4 m-thick), and the lowest part of the Chittenango/Berne Member. Calcareous dark gray shales a meter above the base of the section contain small brachiopods and bivalves; these include the brachiopod Leiorhynchus and the large bivalve Panenka, along with nautiloid and goniatite cephalopods. A 2 m-thick interval of tectonized shale occurs in the upper part of the Union Springs Member above these fossiliferous shales. The Chestnut Street Beds form a 20 cm-thick package of two skeletal wacke/packstone beds separated by gray calcareous shales. The basal Chestnut Street bed directly overlies a 5 cm-thick dark, argillaceous concretionary lime mudstone layer with pyritized burrows. The internal stratigraphy of the Cherry Valley Member at this locality is similar in most ways to that of STOP 1. However, individual packstone beds of the upper massive interval increase in thickness and are separated by shaly partings.

Chittenango Mbr. of the Marcellus Fm.
Note hillside exposure of the Chittenango Mbr. of the Marcellus Fm. on the south side of the road.

Note Carlisle Center and Esopus Fms. in roadcuts.

Note Oriskany and Becraft Fms. in roadcuts south of I-88.

Note Becraft and Kalkberg Fms. in roadcuts south of I-88.

Note Coeymans Fm. in low roadcuts on the south side of the highway.

Manlius, Rondout, and Brayman Fms.
Note exposures of the Manlius, Rondout, and Brayman Fms. in large roadcut to the south of I-88.

Note exposures of Onondaga Limestone in roadcuts and in adjacent Fox Creek for the next 1.5 miles.

Note Onondaga Limestone exposures behind Highway Dept. Building (south of Rte. 443).

Berne and Otsego Mbrs of Mount Marion Fm.
Note that large roadcuts on Cole Hill Rd. feature the type-Berne and the complete Otsego Mbrs. of the Mount Marion Fm. (= proximal marine facies of the upper part of the Marcellus Fm.).

Note small quarry in the Berne Mbr. (south of the road).

STOP 3. Section at Long Road ravine (Thompson's Lake section of Rickard, 1952)
This section illustrates the eastward appearance of coarse-grained siliciclastics in the lower part of the Marcellus Formation. The stop exposes a relatively thick section of the Bakoven Member, a 4.5 m-thick section of the stony Hollow Member, and a 1.4 m-thick section of the Cherry Valley Member.
The Bakoven Member (= Union Springs Member) is exposed downstream from and within the lowermost waterfall. The shales contain carbonate concretion horizons and thin-bedded limestones. Rickard (1952) recognized the true concretionary Cabrieroceras bed near the base of the lowermost waterfall. A 1.75 m-thick interval of tectonized shale occurs in the face of this waterfall.
A 2.0 cm-thick bed of the Lower Proetid Unit occurs at the base of the Stony Hollow Member, just below the crest of the lowermost waterfall. The overlying 1.8 meters of buff-weathering, pyrite-rich, calcareous siltstones and shales are equivalent to the massive sandstone unit near the top of the Stony Hollow in the Hudson Valley (STOPS 4 and 5b). The overlying Upper Proetid Unit consists of a package of coarsely crinoidal packstone and grainstone beds that display relict cross-stratification. Quartz silt and sand are common in these limestone beds at this locality, in contrast to previous stops.
The Cherry Valley Member is exposed within and caps the uppermost waterfall. The lower and upper Cherry Valley intervals are heterolithic at this locality and contain thin interbeds of terrigenous siltstone/sandstone with skeletal packstone and grainstone beds. The middle nodular interval consists of a few large, sharply bounded concretions in dark gray shale. Coarse crinoidal beds with finely comminuted brachiopod valves are common in the uppermost Cherry Valley.

Note sandstone at the top of the Berne Mbr. (Mount Marion Fm.) on right past the intersection.

Note Helderberg Lake on left (north) side.

Note exposures of the Berne Mbr. behind the house at the corner.

Exposures of the lower part of the Marcellus Fm
Note the large parking area on the north side of the road, which provides parking for access to exposures of the lower part of the Marcellus Fm. in and below the falls on Onesquethaw Creek, directly to the north.

Note exposure of Onondaga Limestone in roadcut on north side.

Note quarry in the Otsego Mbr.

Upper part of the Mount Marion Fm.
Note outcrops of the upper part of the Mount Marion Fm. on the south side of the intersection

Note quarry in the upper part of the Mount Marion Fm. on the right (west) side of the road.

Note outcrops of the Plattekill Fm. along the road for the next 0.4 mile.

Note scenic views of the northern Catskills for the next 0.5 mile.

Note exposures of Plattekill Fm. red beds and fluvial sandstones in roadcuts.

Note additional outcrops of the Plattekill Fm. for the next 2.4 miles.

Note outcrops of the Mount Marion Fm. over the next 0.4 mile.

Note scenic view of Potic Mtn. to the left (west).

Note outcrops of the Onondaga Limestone in roadcuts for the next 0.2 mile.

STOP 4. BUTTERMILK FALLS
This locality exposes approximately 41 m of the Stony Hollow Member and 3.7 m of the terrigenous sand-rich facies of the Cherry Valley Member. Strata at the base of the lowest falls lie approximately 12 m above the Bakoven/Stony Hollow Member contact, which is exposed in a ravine 2.1 km to the north (Locality 8).
A 7 m-thick interval in the lowest falls features a series of thin dolomitic beds (ca. 2-22 cm-thick). This interval, which is best seen in the high bank north of the lowest falls, correlates with a similar package of thin dolomitic beds in the lower part of the Stony Hollow Member at Kingston (Locality 13/Stop 5b). Fine-grained resistant sandstones forms the caprock of the lowest falls.
A second falls 4 m upsection is capped by 1.6 m of highly bioturbated, argillaceous sandstone. The lower part of the unit appears medium bedded, and the upper part is massive. Prominent subhorizontal to vertical Zoophycus traces occur in the upper 0.9 m. This unit is also traceable to Kingston (Locality 13, STOP 5b), where it is represented by 0.9 m of fossiliferous, bioturbated fine sandstone.
The main upper waterfall at Buttermilk Falls is capped by the massive sandstone (3.3 m-thick) near the top of the Stony Hollow Member. At this locality, the massive sandstone unit is highly bioturbated and displays a prominent slaty cleavage. A 0.3 m-thick recessed interval of sandy shale separates the massive sandstone from the underlying Lower Proetid Unit. This highly fossiliferous unit is composed of 2-3 separate beds that total 0.6 m in thickness at Buttermilk Falls.
The massive sandstone that caps the main falls at Buttermilk Falls is overlain by siltstones and silty shales in the upper part of the Stony Hollow Member. The Upper Proetid Unit is covered at STOP 4. A 0.6 m-thick sandstone that forms a small cascade upstream of the main falls may correlate with a similar thin unit that overlies the Upper Proetid Unit or the Chestnut Street Beds at most localities.
The Cherry Valley Member forms a 2 m-high falls at the top of the outcrop. The argillaceous sandstone of the Member is highly cleaved and has several recessed carbonate-rich intervals with numerous small brachiopods. The sandstones appear to be highly bioturbated. A small outcrop of sandy shales that is exposed approximately 5 m upstream is apparently part of the Cherry Valley Member. An abandoned quarry in the south bank of the creek exposes the lowermost black shales of the overlying Berne Member.

Note outcrops of the Lower Devonian New Scotland and Becraft Fms. for the next 1.2 miles.

Cross Catskill Creek.

Note outcrops of the Tristates Group
Note outcrops of the Tristates Group (Esopus, Carlisle Center, and Schoharie Fms.) and the Onondaga Fro. for the next 8.9 miles

Cross Kaaterskill Creek.

Glenerie Fm and Helderberg Group
Note exposures of the Glenerie Fm. and the underlying upper part of the Helderberg Group (Becraft, Alsen, and Port Ewen Fms.) for the next 0.6 miles.

Note exposures of the Schoharie and Onondaga Fms. for the next 1.1 miles.

Mount Marion visible to the right of the Thruway.
Note large quarry at the north end of the ridge which exposes the Berne and Otsego Mbrs. of the Mount Marion Fm.

Note exposure of Stony Hollow Mbr. on left (east) side of highway.

Note dark to rusty shales of the Berne Mbr. exposed on right (west) side of highway.

Note outcrops of Stony Hollow Mbr. for the next 0.7 miles.

STOP 5A. City View Terrace Roadcut
This outcrop exposes the upper 10 m of the Bakoven Member and the lower 23 m of the Stony Hollow Member. The transition between the members is gradational at this locality, and it is underlain by a 1-3 m-thick zone of tectonized shale. Calcareous nodules within this interval have yielded Cabrieroceras and another unidentified goniatite (G. Kloc, 1991, personal commun.). The lower strata of the Stony Hollow Member at this locality are thinly laminated and exhibit little to no burrow-mottling (chiefly small Planolites traces). Body fossils are rare and are chiefly small tentaculids (Nowakia?) and rare small brachiopods and bivalves. The upper part of this outcrop is exposed along the adjacent road to the northwest, where thin (ca. 3-10 cm) dolomitic beds appear in the section.

STOP 5B. Large Route 28 Roadcut
This large roadcut exposes approximately 60 m of the Stony Hollow Member. The base of the outcrop lies approximately 11 m above the contact with the underlying Bakoven Member (see STOP 5a). The thinly laminated character of the unit is visible on many of the rock surfaces, and the low degree of burrow-mottling (chiefly small Chondrites burrows) is also notable. These features characterize much of the Stony Hollow Member at Kingston. A series of thin (ca. 3-17 cm-thick), buff-weathering dolomitic beds occurs 11-21 m above the base of the outcrop. Two thicker, buff-weathering units are visible farther upsection (27 and 33 m above the base of the outcrop, respectively). The lower bed (ca. 0.8 m-thick) is underlain by a layer of rusty-weathering burrows and concretions. The upper unit (ca. 0.9 m-thick) features an upper bioturbated sandstone (with Planolites and Teichichnus traces and small rugose corals, and a lower fossiliferous unit featuring hyoliths, coleolid tubes, gastropods, and cephalopods. Small bivalves may also be found in this interval. This unit is correlatable with the lower massive sandstone at Buttermilk Falls (Locality 9, Stop 4).
The next key unit is a thick, massive, light buff-weathering unit (ca. 5-6 m-thick) that is traceable northward along the outcrop belt as far as Catskill. Auloporid corals are scattered throughout the unit, and two horizons feature small streptelasmid rugose corals. The overlying interval (ca. 12 m-thick) is characterized by darker, blocky-weathering, calcareous shale-rich strata.
The top of the outcrop is marked by the resistant, thin-bedded to massive sandstone near the top of the Stony Hollow Member. The base of this interval is marked by the Lower Proetid Unit and an underlying brachiopod-rich bed. The upper surface of the sandstone marks the base of the Upper Proetid Unit at outcrops in the Kingston area.
The overlying transition into the Cherry Valley Member is not well exposed along Route 28, but a complete section through this interval may be seen 1.7 km to the east along Route 209. At the latter outcrop, the top of the thin-bedded to massive sandstone unit is overlain by a 3.5 m-thick interval of silty shales which feature a series of thin, richly fossiliferous beds with proetid trilobites. These beds may have small calcareous nodules or thin limestone lenses. This interval represents the Upper Proetid Unit in the Kingston area. An overlying thin, calcareous sandstone bed contains numerous brachiopods, which include Productella, Kayserella, and Leptaena. The brachiopod bed is capped by a prominent, 60 cm-thick, bioturbated sandstone that lies approximately 5 m below the top of the Route 209 outcrop. The two lower beds of the Cherry Valley Member are present in the upper 2.7 m of the Route 209 cut.

STOP 5C. Cherry Valley Member Along Route 28 And Adjacent Railroad Cut
This roadcut and the adjacent railway cut expose a 10 m-thick section of the terrigenous sand-rich facies of the Cherry Valley Member. At this locality, the member is composed of five highly bioturbated arenaceous units separated by sandy shale intervals. These units range from 0.7-1.4 m.thick. The sandstones display prominent cleavage, especially in the railroad cut. (Note that the upper sandstone is missing in the highway cut and the lower sandstone is exposed downsection from the railway cut.) Body fossils are relatively uncommon in the sandstones, though carbonate-rich nodules feature shelly to styliolinid-rich hashes with abundant quartz sand. Leiorhyncus, other small brachiopods, and auloporid corals may be present near the tops or bases of the sandstone units. Uncommon to rare nautiloid and goniatite cephalopods may also be found. Teichichnus is the most prominent trace in the sandstones. The intervening sandy shales feature numerous limonitic burrows, accompanied by small brachiopods and bivalves.

A9: A SURVEY OF PRECAMBRIAN TO PLEISTOCENE GENERAL GEOLOGY IN CENTRAL NEW YORK
Utica College of Syracuse University
David E. Jones
The Ecosystems Center, Marine Biology Lab
Woods Hole, Ma.
The intent of this field trip is to introduce several aspects of geology covered in the New York State earth science syllabus. We shall examine rocks that range in age from Precambrian to Pleistocene. Many rock types from a wide variety of Paleozoic depositional environments will be seen. Opportunities to collect a wide range of fossils and minerals will be provided. The field trip will develop a tectonic framework of deposition as we move higher into the stratigraphic record. Sedimentary structures and erosional features are well represented at these stops. There are several good photo opportunities of faults and potholes in addition to the rocks. We will also be seeing a wide variety of landscape features produced during the last glacial retreat, including lakes, U shaped valleys, kettle ponds, meltwater channels, sinkholes, and drumlins. An excellent general field trip of the Utica area to the west by Tewksbury and Allers (1984) is highly recommended.

A9: A SURVEY OF PRECAMBRIAN TO PLEISTOCENE GENERAL GEOLOGY IN CENTRAL NEW YORK

Good example of glacial "U" shaped valley erosion.
You will be driving up the Otego Creek Valley, a very good example of glacial "U" shaped valley erosion.

Canadarago Lake to the right.
This lake, a fingerlet, was formed at the end of the last ice age by the blockage of glacial meltwaters downstream which formed a natural dam. Fingerlet: Muskatt's term for a smaller version of a Finger Lake.

Utica Shale and meltwater channel
Outcrop of Utica Shale (Ordovician). To the east, a good meltwater channel can be viewed.

An outcrop of Trenton Limestone (Ordovician) containing trilobites is on the east side of the road.

Precambrian basement material can be seen in an outcrop on route 5 to the east and up the hill.

STOP 1. Potholes and Moss Island
A very good outcrop of Precambrian material can be seen on the NE. side of the road just before reaching the plant. This rock is a quartzose syenite gneiss of Precambrian age. Multiple veins of quartz that have filled fractures in this material attest to a history of deformation in these rocks. Please do not use rock hammers at this outcrop, as the use of them would mar the large pothole, a very unusual erosional feature that is visible here. For some periods of the Pleistocene ice blocked the flow of water through the St. Lawrence River creating Lake Iroquois. This greatly increased the flow of water through the Mohawk R., for some 1000 yrs., from about 12,000 to 11,000 yrs ago, which carved this pothole and those across the river. Across the river is Moss Island. In May, 1976, Moss Is. was declared a National Landmark. It is one of only 400 such registered natural treasures in the U.S. The shoreline of Moss Is. displays several of these potholes, some more than 30 feet deep and about 20 feet in diameter, and makes an excellent photo opportunity. Lock 17, which is the highest lift lock on the barge canal system (40.5 ft.), can also be seen.

STOP 1A. Roche Moutonee in park
In the town park ahead is a good exposure of bedrock that displays roche moutonee glacial alteration.

STOP 1B. Photo opportunity of a well scoured boulder
555 E. John St. Boulder on display in front of the Rockton Plaza was removed from a pothole during excavation.
Photo opportunity of a well scoured boulder, an abrasion tool used by the swirling waters for the creation of potholes.

Moss Island can be viewed on the left (East).

STOP 1C. Parking Lot for church on right, W. of the church.
Walk to fence in the back center of lot. Across abandoned railroad right of way observe nonconformal contact of Little Falls Dolostone (Cambrian) overlying Precambrian syenite gneiss. Dolostone is overlain by classic man made limestone wall.

STOP 2. Outcrop of Late Cambrian Little Falls Dolostone.
This unit directly underlies the Black River Group (Ordovician) in this area. It nonconformably overlies a Precambrian syenite gneiss. The Little Falls Dolostone is a sandy, medium-grained dolostone with some sandstones occurring near the base of the unit. Except for the abundant colonial algae Cryptozoan, not seen at this site, the unit seems to be barren in this area. Quartz crystals from this site are locally known as Little Falls, Herkimer, or Middleville Diamonds. Anthraxolite is a black, lustrous, carbonaceous mineral often found in association with the quartz. Calcite, dolomite, pyrite, marcasite, galena, sphalerite, chalcopyrite, hematite, and glauconite have also been reported.

STOP 3. Paradise Road bridge over Thruway.
Park at S end. Ordovician Dolgeville Facies, a mixture of calcisiltites and black shales, overlain by the Ordovician Utica Shale can be seen in rock cuts on both sides of the Thruway. It is a deeper water facies of the Trenton limestones. The contortions seen in the Dolgeville are considered to be due to a submarine slide when the unit was in a soft sediment phase. Graptolites and trilobites from the Utica Shale exposed in the ditch at the SW corner of the bridge have been found. WARNING: Do not climb down the cliff faces. It is illegal and dangerous to go rock collecting there. Looking at the NE wall a very visible fault can be seen. It the first of many major faults that cross the Thruway further to the East. (This stop is a good camera opportunity).

STOP 4. (LUNCH) North of the road is an abandoned quarry.
This is now part of a private home, so please do not do damage to these rocks. 2-1/2 feet of Gull River Limestone underlie 18 feet of Kings Falls Limestone. These rocks are very fossiliferous, shelly and nonshelly calcarenites from the Ordovician Trenton Group. See stop #2, Cameron (1972) for more detail.

STOP 5. Outcrop of Silurian Otsquago Sandstone
Outcrop of Silurian Otsquago Sandstone, a formation of the Clinton Group. Coarse red sands, cross bedding well displayed. Interbedded green shales represent the Sauquoit Formation seen further to the west. A deltaic distributary channel environment of deposition is postulated for these rocks.

STOP 6.Intersection of routes 20 and 166.
Drive under the Route 166 bridge and park along the outcrop on Route 20. Kalkberg Limestone, Oriskany Sandstone, Esopus shale, Carlisle Center and Onondaga Formations. A 1-3 cm (Tioga) bentonite (volcanic ash) layer is found in the Kalkberg. It has been dated as being about 395 million years old. Several rock types are visible at this outcrop that represent a wide variety of Devonian depositional environments. See Fisher (1979), stop #6 for more details.

Glimmerglass State Park on right.

STOP 7. Road Cut in Dugway Rd. Otsego shales (Middle Devonian).
Epifaunal filter feeders were very common in this deltaic environment. The rise of highlands in the east (due to tectonic uplift) have altered the environment of deposition to something quite different from those seen at Cherry Valley. For more information, see Grasso ( 1977).

Start of the Susquehanna River.
A small park at the junction with Lake Street marks the start of the Susquehanna River. Here the waters of Otsego Lake flow over a Quaternary moraine that dams the lake.

A10: HYDROGEOLOGY OF GLACIAL DRIFT IN THROUGH VALLEYS NEAR DRYDEN AND CORTLAND, NEW YORK
TODD S. MILLER AND ALLAN D. RANDALL
The Appalachian Plateau physiographic province encompasses nearly all of southwestern New York (fig. 1, inset). About 85 percent of this region consists of till-mantled bedrock uplands; the remainder consists of broad valleys that are partly filled with stratified drift. The stratified drift includes coarse-grained sand and gravel deposits that are the only highly productive aquifers in the region; it also includes extensive fine-grained sediments that do not yield usable amounts of water. The divide between streams that drain northward to Lake Ontario and those that drain southward to the Susquehanna River crosses some of these broad valleys, which are termed "through valleys" because they are continuous across a major topo.graphic divide. An area of unusually hummocky topography near the divide in each through valley suggests the former presence of buried ice; these areas were collectively termed the Valley Heads moraine by Fairchild (1932).
This article briefly describes current concepts of (1) the stratigraphy of stratified-drift aquifers and confining units in valleys within and south of the Valley Heads moraine, (2) recharge to those aquifers, and (3) their potential for use as sources of large water supplies during dry periods. These concepts were developed over the past few years from geohydrologic studies, cited herein, that emphasized or included valleys near Dryden, Harford, and Cortland (fig. 1). The article concludes with the log of a field trip that is intended to illustrate several of these concepts and to offer an opportunity for discussion of what is and is not known about these aquifer systems.

A10: HYDROGEOLOGY OF GLACIAL DRIFT IN THROUGH VALLEYS NEAR DRYDEN AND CORTLAND, NEW YORK

STOP 1: Site Of Former USGS Gaging Station On Gridley Creek.
This site is near a preglacial drainage divide now crossed by Gridley Creek, whose flow was reversed by glaciation. It is a good site at which to measure basin yield because the valley fill is only 500 feet wide and probably not thick; therefore, ground-water underflow through permeable sand and gravel is likely to be small, and nearly all runoff leaves the watershed in the stream, where it can be measured.

Ski area on left.

Meltwater spillway ahead on left
Meltwater spillway ahead on left, incised into south end of mound of drift that Route 392 crosses just ahead. The divide between east-flowing Gridley Creek and west-flowing Virgil Creek is here, in the middle of a valley 2,000 feet wide.

Summit, view (to rear) across valley of Virgil and Gridley Creeks.

Route follows East Branch Owego Creek. Kame terraces on right side of valley.

Kame terraces on both sides at intersection.

STOP 2: Hesitation Stop: Harford Underground Gas-Storage Project.
In 1953, a cavity was excavated by solution mining in salt beds at a depth of about 3,000 feet to provide storage space for liquified petroleum gas that would arrive here by pipeline. The brine created by mining was discharged to lagoons excavated in the permeable outwash and alluvium on the valley floor. A few years later, many residents of Harford Mills, visible to the south, began to pump salty water from their shallow wells. Water sampling, resistivity surveys, and a test well disclosed that outwash extended to a depth of 56 feet and contained salty water over a large area near the hamlet and Owego Creek, except close to the water table, where water was fresh (Dunn, 1967, 1968). Gravel layers at depths of 97 and 170 to 194 feet yielded fresh water.
The raised, lined pond visible here is now used to contain brine produced during operation of this facility.

STOP 3: Cheese Factory Brook.
Except during the spring freshet and other brief periods of unusually heavy runoff, this brook ceases to flow somewhere near or downstream from this former creamery. We hope to view the point of dryness, note exposures along the brook, and discuss the significance of seepage losses from tributaries as a source of recharge.

STOP 4: Springs Along Cheese Factory Brook.
About 0.2 mile upstream from the creamery, a reservoir (now in disrepair) was built to develop a spring at the base of the bluff along Cheese Factory Brook. Exposures upstream and downstream show that the bluff consists of sandy, somewhat silty gravel. The presence of the spring suggests that impermeable sediment is not far below. On April 25, 1991, a tributary just upstream went dry 300 feet before it reached Cheese Factory Brook. Seepage from the tributary may be a major source of water to the spring.

STOP 5: Streamflow And Water-Level Measurement Sites.
This is the location at which the water levels in figure 7 were measured. Most runoff from the 3.42 square-mile watershed above this point occurs as underflow through the stratified drift.

STOP 6: Pit In Crevasse Filling.
Locked gate ahead, permission from Harford Teaching and Research Center farm manager required to enter; continue 0.1 mile to pit. Brook to left of dirt road flowed past Route 38 April 25,1991.
This infrequently used pit is on the property of the State College of Agriculture's Harford Teaching and Research Center. About 10 feet of till that contains only rounded pebbles overlies about 20 feet of stratified, sorted but very silty gravel and, in places, deformed medium to fine sand, silt, and clay. Poorly sorted, silty gravel is characteristic of early, deglacial, proximal stratified drift near the Valley Heads moraine.

Harford Teaching and Research Center main buildings on left.

STOP 7: Daisy Hollow Brook.
Daisy Hollow brook flows farther out onto the valley-floor outwash than any other tributary near Harford. One reason why may be observed here. Also exposed is the flat-stone drab gravel that is typical of alluvium along upland tributaries.

This terrace like flat is capped by till.

STOP 8: Southworth Road Exposure Near Dryden.
The large variety of sediments in this exposure illustrate the complexity of the depositional environment at the Valley Heads moraine. Figure 4 shows the appearance of the exposure in 1984. Sediment facies include till, fluvial, and lacustrine deposits. The drab till at the top of the exposure represents a readvance of ice during the late stages of Valley Heads glaciation. The surficial till overlies a coarse, cobbly gravel that in turn overlies either a discontinuous pebbly sand or till hummocks. Till hummocks have pockets of gravel, disturbed sand stringers, and some folded bedding, all of which suggest movement of the sediments such as may occur during topographic inversion. Beneath the hummocks is rhythmic silt/clay with scattered stones, presumably dropped from floating ice. A till containing abundant bright clasts underlies the rhythmite. A bright, coarse, cobbly gravel underlies the bright till.

STOP 9: Gravel Pit At South Cortland
Coarse outwash and ice-contact sediments deposited by Valley Heads ice. Note boulders 2 to 3 feet in diameter at entrance to pit. Excavation is along the boundary between outwash deposited by northeastward-flowing meltwaters and ice-contact deposits laid down on and adjacent to blocks of ice that were in the middle of the valley. A geologic log of a test well in the gravel pit indicates the following stratigraphy, in feet below land surface: 0-45 feet sand and gravel, 45-50 till, and 50-75 sand and gravel. Mining of sand and gravel will stop 10 feet above the water table so as to minimize the effects on water resources and so that land could be used after mining operations cease.

STOP 10: Hesitation Stop: Remediation Of A Spill Of Organic Solvent.
A recovery well pumps about 970 gallons per minute to remediate the source area (O'Brien & Gere, 1991). Pumped water is routed through an air stripper, which brings sufficient air into contact with the water to allow the volatile organic solvent to evaporate. The water is then discharged into infiltration lagoons, where it seeps to the water table.

STOP 11: City Of Cortland Well Field.
Otter Creek flows through the well field but is usually dry from midsummer to late fall. During low-flow periods, when well 3 is turned on and streamflow disappears in Otter Creek because of induced infiltration. When the well is turned off, streamflow reappears. Abundant vegetation in the channel indicates a relatively large amount of nutrients in the water. In contrast, the channel of nearby Dry Creek contains little or no vegetation, which suggests that runoff from that drainage basin contains relatively few nutrients.
An air-stripping tower was installed beside the main plant in anticipation that the plume of organic solvents (source about 2 miles southwest, stop 10) would reach the well field. Concentrations of trichlorethylene within the plume decrease with distance from the source, and only trace amounts have been detected at the well field, not enough to warrant use of the air stripper. The decrease in concentrations has been attributed to volatilization, discharge to Otter Creek, and biological degradation and transformation of the trichlorethylene.
Well 4 at plant 2 is one of the most productive municipal wells in New York. It is capable of pumping 4,000 gallons per minute. The well taps outwash 63 feet in saturated thickness. At present, it is used only intermittently.
-

B1: FIELD ILLUSTRATIONS OF ROCK TYPES AND GEOLOGIC FEATURES IN THE UPPER SUSQUEHANNA VALLEY ADJACENT MOHAWK REGION
David M. Hutchison
The outcrops and surficial features observed on this trip have been selected (1) to show students the change in lower Paleozoic stratigraphy through time (2) to illustrate several sedimentary and topographic features (3) to help students gain a better understanding of the geologic framework of this area.
The trip starts at the large Upper Devonian flood plain channel behind the F.W.Miller Science Building on the Hartwick College campus in Oneonta and ends in Precambrian garnet gneiss six miles east of Canajoharie. Progressively older beds are exposed to the north because of three factors: the gentle southerly dip of the beds, the erosion by the Mohawk River and the uplift, tilting and erosion of large fault blocks associated with normal faults in the Mohawk River Valley.
The clastic sediments are the result of the Middle Ordovician Taconian Orogeny (470-435 m.y. ago) and the Middle and Late Devonian Acadian Orogeny (J85-355 m.y. ago) (Fisher. 1965). Both of these times of crustal unrest and uplift east of the Hudson River and in New England provided an influx of clays, silts and sands into the Ordovician and Devonian seas which occupied the area of this field trip. The carbonate rocks were deposited by these seas during periods of quiescence between orogenies.

B1: FIELD ILLUSTRATIONS OF ROCK TYPES AND GEOLOGIC FEATURES IN THE UPPER SUSQUEHANNA VALLEY ADJACENT MOHAWK REGION

STOP 1. Upper Devonian Oneonta Formation
STOP 1. Upper Formation Devonian Oneonta
This outcrop consists of dark grey shales, thinly bedded siltstones and sandstones. A massive sandstone which fills in part of a Devonian stream channel is well exposed for about 150 feet at the left end of the outcrop. There is an erosion surface between the underlying shale and the overlying massive sandstone. This surface which marks the bottom of the channel rises stratigraphically to the right. Interference ripple marks are exposed just below the road level. Plant materials are abundant in some layers. A few galena crystals about 1 mm across have been found in the thinly bedded sandstone.
Trilobites, marine pelecypods and brachiopods of the Gilboa Formation have been found in beds stratigraphically 75 feet below this outcrop, and marine fossils are found in thinly bedded siltstones and shales stratigraphically 200 feet below stop 1. This outcrop is next to Nick's Diner on Chestnut Street (Route 23) . We probably will not stop here today.
A clean sandstone which shows extensive trough-type cross bedding crops out in the woods between Stop 1 and Stop 1A.

STOP 1A. Red mudstones and shales
Red mudstones and shales with root casts, worm burrows and ripple marks are exposed at the top of the hill just below the Ernest B. Wright Observatory which houses a 16" telescope. Walk or drive (if the sliding chain link fence gate is open) up the hill at the far end (west) of the Binder Physical Education Building parking lot. Continue up the hill through the second gate to the outcrop below the Observatory next to the practice soccer field.
The view down the valley is looking southeast to Mt. Utsayantha in Stamford (about 30 miles map distance). The broad U-shaped valley is the result of Pleistocene glaciation. The Susquehanna River flows in from the north (out of your view) and through the city of Oneonta. The terraces on either side of the valley are kame terraces. Red beds are exposed near the top of the hills across the valley.

Cross Susquehanna River.
Clays indicate a glacial lake occupied this area. If you want to study the clays you should go past junction with County Road 35 and park in small area to the right along Route 166.

STOP 6. Lower Devonian Kalkberg Limestone
The Lower Devonian Kalkberg Limestone is exposed in a fresh outcrop. This is a medium grained, thin to medium bedded limestone with abundant chert. There are numerous brachiopods, bryozoans, some corals and trilobite fragments. A 2" thick layer of bentonite is exposed near the eastern end of the outcrop. At the east end of grassy field below outcrop there is a small creek that disappears into a sink hole in the limestones.

STOP 10. Precambrian garnet gneiss
Follow the foot path at the east end of the outcrop to the railroad cut. Beware of Poison Ivy along the path and at the Railroad cut.
Rusty weathering Precambrian garnet gneiss exposed along the south side of the road and in railroad cut.
The folded Precambrian gneiss is overlain by the Upper Cambrian Little Falls Dolostone. The dolostone is brecciated for several feet above the contact with the gneiss. Apparently there was movement along the unconformity during Ordovician time when the normal faults in the Adirondack Mountains and the Mohawk River Valley were formed. There are also good exposures of the gneiss north of this outcrop across the Mohawk River along route 5 (5.4 miles east of Palatine Bridge).

B2: ENVIRONMENTAL GEOLOGY AND HYDROLOGY OF ONEONTA AREA
BRENT K. DUGOLINSKY
State University College at Oneonta
Oneonta, New York 13820

STOP 1: Wilber Lake Reservoir
Wilber Lake serves as the principal water supply for the city of Oneonta and adjacent suburban areas. The lake itself covers an area of approximately 90 acres when full and receives runoff and infiltration from a drainage basin of only about 1650 acres. Relief within this drainage basin is 393 feet, with the highest elevation being 1928 feet. Nearly 80% of the drainage basin is forested mainly with mature hardwoods and pine. Some selective lumbering has occurred over the years, but clear-cutting of trees has not, and lumbering has apparently had minimal effect on the drainage characteristics within the basin. The remaining area is comprised of fields, pastures and open bushy areas. The city owns or controls most areas adjacent to the reservoir and no development is allowed. Surface deposits around the lake consist of a silty clay glacial till matrix with shale and siltstone slabs in a layer ranging from about seven to twelve feet thick, decreasing in thickness on the surrounding hillsides to a little over five feet (Walker, 1985).
The lake contains approximately 450 million gallons of accessible water, with another 70 million gallons contained below the water supply intake pipes. According to water treatment plant personnel, the present water use is highly variable, but typically averages about 1.5 million gallons per day (roughly 100 gallons/person/day), or approximately 550 million gallons per year. This requires more than one complete recharge of the lake every year, which only occurred for five years between 1958 and 1982 (Walker, 1985). These years were fortunately when water demands were less than present, but increasing demands since that period have necessitated the search for supplementary sources of water. The largest single users of the city's water supply are the colleges (Hartwick College and the State University College) and water usage varies greatly depending on whether or not one or both colleges are in session since the student population is greater than one-third of the total city population.
The lower reservoir holds an estimated 25 million gallons maximum (probably considerably less due to sedimentation). The water treatment plant will not use water from this source deeper than about two or three feet because of the amount of suspended sediment in the water column. Even with this additional supply, it would only equal a few days supply at the present demand. Supplementary sources include a well drilled west of the city in 1941 for industrial uses but was never used. It is now on property owned by the New York State Electric and Gas Company and was leased to the city in 1982. This well has been connected to the city's water main and can provide up to about one million gallons per day (1.5 cubic feet/second) for four months (Arthur Palmer, pers. comm.), but is only used at about half that capacity. This supply is only used when necessary due to the rust scale in the pipes. Water must be pumped back against the normal flow direction in the mains, which increases the rust scale and discoloration problem. Also, any treatment (such as chlorination) must be done at the well head. Another well drilled in Wilber Park can provide up to about 250 thousand gallons per day. This well is near the water treatment plant and is connected to the water supply pipe to the plant, but is presently not in service. A last resort supplementary supply is possible from the Susquehanna River. Problems with this source are discussed later, as this is one of the stops (#3) on this trip.

STOP 2: Water Treatment Plant
The city's water treatment plant, located on East Street near the high school, treats an approximate average of 1.5 million gallons of water per day from Wilber Lake with chlorine at the rate of 12-18 pounds/day, the rate dependent upon water demand. Also, the supplementary water supply from the West End well is treated daily with 4 to 5 gallons of sodium chloride solution at the well head when this well is being utilized.

STOP 3. Mill Race Pumping Station
The mill race, originally constructed to divert water from the Susquehanna River to provide water power to mills located downstream, now serves as a flood control channel and as a possible supplementary source of water for the city. The small brick building contains a pump which can divert water from the intake immediately above the small dam on the mill race to the reservoir via the pipe visible in the streambed which enters the mill race at the dam. However, this water source is highly undesirable and is viable only in an emergency. There is a high algae content which results in discoloration and an undesirable taste. The water may be polluted with other contaminants as well. Perhaps more significantly, during a drought, when supplementary water supplies would be most needed, the river level would be too low to provide water to this channel. Also, during winter months, it is likely that the water in the above ground pipe from the pumping station to the reservoir would freeze.

STOP 4. Neahwa Park-Buried Hazardous Waste Site
From 1881 until 1953, a coal gasification plant operated in the general area now occupied by the baseball field and adjacent buildings along Gas Avenue in what is now part of Neahwa Park. The plant was originally constructed in 1881 by the Oneonta Gas Light Company, which merged with the Oneonta Electric Power and Light Company in 1887. In 1918, it became part of the Ithaca Gas and Electric Company, which itself became part of New York State Electric and Gas Company (NYSEG). With the advent of cheaper petroleum, natural gas and electric power, the plant closed in 1953 after 72 years of operation. Most of the buildings were dismantled in 1956 and the remaining buildings and property were sold to the City of Oneonta in 1966. The site has since been used for the city garage and storage of city highway equipment, the dog pound, a road salt storage facility, and presently as a minor league baseball field. While in operation, this plant produced gas for heating and lighting from coal, as well as many by-products which are now known to be hazardous. Some of these by-products were buried in the immediate vicinity and were not discovered until recent excavations to repair the Gas Avenue bridge were begun.
NYSEG hired professional consultants to analyze the soils and groundwater in the area, including those from several drilled test wells and excavated pits, in order to determine any present or potential hazard. The initial site survey was initiated in April 1986 and the final technical report was published in February 1990. Analyses of soil from the test pits indicated the presence of the following material (TRC Environmental Consultants, 1988):
A. Aromatic hydrocarbons
| | benzene
| | chlorobenzene
| | 1-2-dichlorobenzene
| | 1-4-dichlorobenzene
| | ethyl benzene
| | toluene
B. Polynuclear aromatic hydrocarbons (PAHs)
| 1. Carcinogens |
| | benzo (A) anthracene
| | benzo (A) pyrene
| | benzo (B) fluoranthene
| | benzo (K) fluoranthene
| | benzo (GHI) perylene
| | chrysene
| | dibenzo (A,H) anthracene
| | indeno ( 1-2-3 CD) pyrene
| 2. Non-carcinogens |
| | acenaphthene
| | acenaphthylene
| | anthracene
| | fluorene
| | naphthalene
| | phenanthrene
| | pyrene
C. Non-chlorinated phenols
| | 2, 4-dimethylphenol
| | methyl-4, 6-dinitrophenol
| | 4-nitrophenol
| | phenol
D. Inorganic compounds
| | cyanide
| | iron
| | zinc
| | sulfate
| | organic nitrogen
It is assumed that these various materials are derived from the estimated 220,000 gallons of dry tar buried in this area over the history of the gasification plant operation. Although the above list of materials may sound devastating, it was determined that although present, these materials occur in such low concentrations as to be considered safe in their present location deep beneath the surface (TRC Environmental Consultants, 1990). In fact, it was determined that excavation and attempted removal of these materials may present a greater risk while simultaneously presenting the problem of what to do with the material once it is removed. It is doubtful that all of the materials could be retrieved in any case. Groundwater movements are being monitored and excavations in the area are prohibited to prevent this material being exposed. The site has been taken off the hazardous site list by the New York State Department of Environmental Conservation and any remediation will come under the control of DEC's Water Division (rather than the Hazardous Waste Division). However, controversy between City officials and the DEC officials continues. One problem includes the fact that State standards are less strict than Federal standards and if Federal standards were followed, the site would still be on the hazardous site list and may therefore qualify for Superfund cleanup. However, DEC officials state that Superfunds were used only when a site had been abandoned or the responsible party was bankrupt or uncooperative. This is not the case and NYSEG and DEC officials plan to work together to develop a remediation plan if it is determined to be necessary.

STOP 5: Hodges Pond
One of the main attractions within the city's Neahwa Park is Hodges Pond. Although swimming is not allowed, it is stocked with small fish (bluegills, etc.) and becomes an ice-skating rink in the winter months. However, recent years have shown dense weed growth in the pond and it was becoming less aesthetically enjoyable as a result. Annual weed removal was expensive and was a temporary solution at best. It was decided in 1990 to drain the pond and dredge much of the bottom mud. Also, to control weed growth without resorting to herbicides, one plan is to lower the water levels in the fall and allow freezing winter temperatures to kill the roots of the shallow water weeds.
Another potential problem is that groundwater movement in this area is generally from the area of the coal tar contamination (STOP 4) toward Hodges Pond. The potential effects of this on the pond are presently unknown.

STOP 6: Southside Mall - Planned Mining
The hill of glacial gravels at the east side of the shopping mall is owned by a local developer who plans to remove the hill and use the material to fill in wetlands along the Susquehanna River about one-half mile to the west (STOP #7). The advantages include allowing more room for expansion of the mall and/or other forms of commercial development as well as providing more potential development space in the area to be filled. However, local environmental groups (City Environmental Board, Audubon Society, and others) and private citizens who realize their responsibility for the stewardship of the environment are concerned about the effect of such massive changes to the local area. Questions have been raised not so much in regards to the removal of the gravel hill but more in terms of the effect of filling in the present floodplain/wetland area along the river. These concerns will be explained at our next stop, which is at the planned fill site. Other potential problems concerning the removal of the hillside gravel include the traffic congestion and the impact on the road surface itself from the hundreds of truckloads of gravel that will have to be hauled continuously over several months. As of this writing, the planned operations are "on hold" until all required permits are obtained by the developer from appropriate State offices (Department of Environmental Conservation, Department of Highways, etc.).

STOP 7: Southside Wetlands - Planned Filling
Most of the area between the highway and the river would be filled with the gravel from the hill adjacent to the shopping mall (STOP #6). As can be seen, most of the trees have already been cut and the developer is apparently only waiting for final approval from State agencies.
One of the principal environmental concerns regarding this operation would be the possible increased potential for flooding. The Federal Emergency Management Agency (FEMA) includes this area within the 100-year floodplain of the river, defined as being at the 1090 foot elevation. Without this area available to help contain floodwaters, it only means that other areas will suffer increased flooding, including city residential and commercial areas. Also, increased stream flow may result in increased erosion downstream. Of particular concern would be the possible erosion of the stream bed adjacent to bridge foundations. Besides the obvious destruction of the wetland habitat, groundwater properties, water tables and drainage characteristics may be adversely affected. A main point of contention is the fact that the developer has not mentioned what his ultimate plans are for this area once it is filled and ready for development. Without knowing what kind of commercial development is planned for this area makes it difficult for even non-environmentally concerned citizens to decide what is best for this area. Most people appreciate the financial benefits of commercial development in their area, as long as they have input on controlling what type of development is planned.

STOP 8. River Access - Erosion Control
This river access site is at the downstream end of a section of the Susquehanna River which was straightened in order to allow the construction of the adjacent section of Interstate 88 to proceed without the added costs of building bridges over the original river meanders. This resulted in the river flowing in a nearly straight line for over a mile. Since rivers naturally develop meanders, especially when flowing over land with minimal gradient, man has had to prevent meander development by lining the river banks with large boulders ("rip-rap"). This also tends to increase downcutting in the restricted channel since flow velocity will increase during increased discharge if it is not allowed to widen its channel. A quick glance downstream should point out the potential hazards of increased erosion caused by natural flooding or from removal of upstream wetland areas which can store floodwaters for gradual release. One of the bridge foundation supports is located in mid-stream and may be weakened by erosion.
Notice also how the flow velocity differs across the river at a meander. This should help explain why there are no boulders to prevent erosion on the inside bend of a meander. Rather, sediment is deposited in these areas of lower flow velocity.

STOP 9: Wastewater Treatment Plant
The Oneonta wastewater treatment plant is classified as a secondary treatment process which involves biological treatment to break down the organic materials followed by chlorination to eliminate potentially harmful bacteria. The average daily volume of water treated in 1990 was 3 million gallons but the plant has a maximum capacity of about 3.6 million gallons daily. According to the manager of the plant, one reason for the higher volume of waste water treated than the volume of reservoir water entering the city supply mains is infiltration of groundwater into some of the older permeable sewer pipes. Also, there are some homes in the town that may be connected to the sewer lines but may have their own private wells rather than being connected to the city water supply.

STOP 10: Transfer/Recycling Station
The transfer/recycling center was opened in 1988 when recycling became mandatory in the City of Oneonta, one of the first cities in this area to do so. Recyclables are separated by the generator (individuals, businesses, etc.) and either picked up by commercial haulers during the regular garbage pick-up schedule or brought to the station by individuals. Present materials that are removed from the waste stream and recycled include newspapers, certain types of plastic, glass (clear, green and brown are separated), corrugated cardboard, cans, tires, car batteries, used motor oil, and green waste (grass clippings, leaves, branches, Christmas trees, etc.). Newspapers, cardboard, cans and plastic containers are compacted into bales for shipment to available markets for reuse. Glass bottles are crushed before shipment in order to reduce the volume. The remaining garbage is compacted and transferred by truck to a landfill in Montgomery County.
The facility was taken over by the Montgomery -Otsego -Schoharie Authority (MOSA), which controls garbage collection and recycling in the three county area. A program to begin recycling glossy paper, magazines, junk mail, and similar material is planned to begin this fall. Future plans include the mixing of green waste with sewage sludge to produce a composted material which could be used by farmers or other citizens to enrich their fields and gardens. In many larger metropolitan areas, the use of sewage sludge in this way is not feasible due to the high levels of industrial heavy metals or chemicals it contains. It is also hoped that large-scale recycling of other plastics (such as styrofoam and brittle plastics) will be feasible with further advances in recycling technology and the subsequent development of markets for this material.

B3: FRESHWATER CARBONATE FROM THE UPPER DEVONIAN CATSKILL MAGNAFACIES, DAVENPORT CENTER, CENTRAL NEW YORK
Robert V. Demicco
JohnS. Bridge
Kelly C. Cloyd
Binghamton, New York 13902-6000
Earth Sciences Department
SUNY-Oneonta
The depositional landforms of glacial origin on the Appalachian Plateau of central New York are atypical of classic continental environments. They consist of an unconventional landform assemblage formed by retreating ice-tongues at the margin of the Laurentide Ice Sheet. Landforms representative of back-wasting occupy most through-valleys, while widespread stagnation and down-wasting occurred in non-through valleys. A modified ice-tongue model includes valley tongues 20 km long and emphasizes the significance of in-wash as a primary source of sand and gravel, and subglacial sediment flow within tunnels as the major source and transport mechanism for silt.

B4: ACTIVE AND STAGNANT ICE RETREAT: DEGLACIATION OF CENTRAL NEW YORK

Dead-ice sink on right

Unadilla River

STOP 1. New Berlin: Through valley landforms
Through valley landforms - deltaic valley train and dead-ice sink.
Large-scale deltaic foreset beds exposed here and within a currently inactive quarry in the center of the valley contain clast supported, very coarse gravels and pebbly, coarse sands; leached and re-precipitated carbonate (limestone) form partial cement in some units. This valley train is breached by the Unadilla River that flows from a dead-ice sink up-valley to a lacustrine plain down-valley. Landforms indicate detachment of large ice mass during active ice retreat.

Road rises on gravel terrace above lacustrine plain

High-level terrace (1280') on west side of valley
High-level terrace (1280') on west side of valley above road (continues for 1.5 miles) is of unknown origin.

Road rises on pitted planar gravel and kame field

STOP 2. Columbus Quarters: kame field and pitted plain in through valley.
These landforms, breached by the Unadilla River at its confluence with Tellette Creek, may have served to temporarily dam a local lake up-valley. Pebble counts from upland drab drift and kame field bright drift suggest tributary in-wash from the Tellette Creek drainage basin was a partial source of sediment (see Case # 4 for discussion of pebble count data).

Proceed east across lacustrine plain

Road descends onto the pitted and discontinuous valley train of Butternut Creek.

Road descends onto the kame and kettle topography of the moraine at Oaksville.

Road crosses the crest of the moraine
Road crosses the crest of the moraine and continues on and off the moraine for next 1.5 miles through the villages of Oaksville and Fly Creek.

STOP 3. Fly Creek: Valley train and dead-ice sinks in through valley.
Sand and gravel valley train with classic assemblage of glacio-fluvial sedimentary structures. What criteria may be used to distinguish outwash from in-wash?

STOP 4. Cassville-Cooperstown moraine at Index
This classic through valley landform (moraine and associated valley train) represents active ice deposition. It consists of stratified sand and gravel that grade up-valley into silt 120+ feet thick (see Case #1, Figure 2). Is it an end moraine, as proposed by Krall, 1977, or a recessional moraine? Although high enough, it did not dam Glacial Lake Cooperstown. Landforms and stratigraphy between here and Otsego Lake suggest detachment of a marginal-ice cleat and development of a dead-ice sink (see Case #1, Figure 4).

Dead-ice sink
Dead-ice sink behind Cassville-Cooperstown moraine occupies the valley for the next mile.Dead-ice sink behind Cassville-Cooperstown moraine occupies the valley for the next mile.

STOP 5. Council Rock Park on Doubleday Ice Margin
Well data indicate 180 feet of bouldery silt beneath a moraine that plugs the valley and dams Otsego Lake. Subtle hummocky terrain in the village of Cooperstown can be traced westward to the golf course. While ice-cored, this landform dammed Glacial Lake Cooperstown at an elevation of 1250'. The view northward reveals conspicuous cross-sectional valley asymmetry, which is an important aspect of sediment source for Glacial Lake Cooperstown (see Case #1, Figures 5-9).

Highway traverses Cassville-Cooperstown moraine.

Hamlet of Hyde Park
From here south for several miles, planar gravels appear related to upland tributary in-wash sources.

Valley floor consists of lacustrine clays
Valley floor consists of lacustrine clays from here south to a moraine at Portlandville

STOP 6. Goodyear Lake overview at Milford Center
Pitted valley train and dead-ice sink. These landforms indicate local stagnation of the valley ice-tongue during active retreat. However, the valley fill consists of 60+ ft. of ice-contact stratified drift over 300+ ft. of silt interpreted to be of lacustrine origin. Does the stratigraphy indicate two stades (re-advance) or is there a single-stade environment that accounts for both stratigraphic units? Aggradation over ground ice islands is suggested.

Dead-ice sink right and left

Road parallels Charlotte Creek through the moraine on the right.

STOP 7. Davenport Center: Pine Lake Dead-ice Sink Complex.
These kames and sinks formed in an ice-cored terrain at the mouth of Charlotte Creek where the valley was clogged by remnant ice. Case # 3 considers the origin of landforms here. Also see Case # 3, Appendix A for the results of a pebble count study that tested an in-wash origin for these materials.

Cross the lacustrine plain of Glacial Lake Davenport.
Right hand fork goes downhill and across the lacustrine plain of Glacial Lake Davenport.

STOP 8. Davenport Center: pitted hanging delta.
Current and past exposures contained well-developed, large-scale deltaic foreset beds in a hanging delta marked by kettles 40+ ft. deep. This indicates progradation onto and across grounded ice in Glacial Lake Davenport. See Case # 3 for discussion.

Highway traverses moraine at West Davenport.

Terrain to the left is what may be the only lateral moraine in this area.

Road descends to Susquehanna valley lacustrine plain.

Breach of the Oneonta moraine
Highway enters the breach of the Oneonta moraine (significantly altered by urban development).

Down-valley view south across local kame field.
Pull over and walk up Winnie Hill Road 0.1 mile. for down-valley view south across local kame field.

STOP 9. Village of Laurens landfill
Ice-contact stratified drift. At various times, excavation has exposed tilted and truncated sequences of inter-stratified gravel and pebbly sand with fluvial sedimentary structures and local silt layers of lacustrine origin. This is interpreted to indicate semi-continuous aggradation of ice-cored terrain. Tributary in-wash from the west is a possible sediment source.

Planar gravel, valley train remnant for next half mile.

STOP 10. Otsego County sand and gravel quarry: planar gravel remnant.
This landform, typical of many others within the Otego Creek valley, is a discontinuous, planar gravel deposit interpreted as a remnant of a surface of aggradation that included semi-continuous ice masses as vestiges of a collapsed ice tongue. Ice-contact fluvial and lacustrine facies are common.

Road rises onto pitted planar gravel remnant.

Road traverses terrain of ice-cored origin including a small esker out of sight to the right.

STOP 11. Overview of meltwater channel
Overview of meltwater channel through discontinuous planar gravel remnant and terrain of ice-cored origin.

Road descends to a local lacustrine plain (dead-ice sink?)

Gravel excavation to the left removed a landform thought to be a proto-esker.

STOP 12. Overview of discontinuous, planar gravel surface
Overview of discontinuous, planar gravel surface and terrain of ice-cored origin bordering a local, up-valley lacustrine plain.

STOP 13. Overview of headward area in non-through valley.
Valley floor contains a few isolated kames. Unlike through valleys, the valley floor gradually rises to upland slopes across which ice flow diminished during glacial retreat resulting in downvalley ice-tongue starvation and collapse.

B5: UNDERSTANDING THE EAST CENTRAL ONONDAGA FORMATION (MIDDLE DEVONIAN)
-AN EXAMINATION OF THE FACIES AND BRACHIOPOD COMMUNITIES OF THE CHERRY VALLEY SECTION, AND MT. TOM, A SMALL PINNACLE REEF
THOMAS H. WOLOSZ
SUNY College at Plattsburgh
Plattsburgh, N.Y. 12901
HOWARD R. FELDMAN
Biology Department
Touro College New York, N.Y. 10035
RICHARD H. LINDEMANN
Saratoga Springs, N.Y. 12866
DOUGLAS E. PAQUETTE
Safety and Environmental Protection Division
Brookhaven National Laboratory
Building 129
The Onondaga Formation of New York and Ontario, Canada has been extensively studied (see Oliver, 1976 for references), and yet is still poorly understood. It is a unit which is, in the western part of New York and in Ontario, clearly transgressive, and yet it lacks any of the classic peritidal facies associated with shallow water carbonates. It is a "reefy" unit, but the major reef building paleocommunity of the Middle Devonian (stromatoporoids and algae) are either extremely rare or absent.

B5: UNDERSTANDING THE EAST CENTRAL ONONDAGA FORMATION (MIDDLE DEVONIAN)

STOP 1. Cherry Valley Section.
Park along road at top of west end of road cut. An almost complete section of the Onondaga Limestone is exposed along this cut. (See discussion of Stratigraphy and Brachiopod Communities).

STOP 2. Mt. Tom Reef.
Mt. Tom Reef makes up the large hill to the south of the road (See discussion of Mt. Tom).

TOP 3. Mt. Tom #6
Mt. Tom #6 forms the low, wooded ridge to the southwest of the road (See discussion in test).

STOP 4. Intersection of Collins and Geywittz Roads.
Leave cars and proceed east from the intersection. Mt. Tom #2 forms the low hill to the south of the small creek, and small outcrops may be examined along the south side of the creek valley on the hill itself. A small quarry the northwest edge of the hillside exposes bedded Edgecliff facies, a small rugosan mound is located just to the southeast of the quarry among the trees. (See text for discussion.)

B6: STORM-DOMINATED SHELF AND TIDALLY-INFLUENCED FORESHORE SEDIMENTATION
-UPPER DEVONIAN SONYEA GROUP, BAINBRIDGE TO SIDNEY CENTER, NEW YORK
DANIEL BISHUK JR.
Groundwater and Environmental Services, Inc. (GES)
300 Gateway Park Drive
North Syracuse, New York 13212
ROBERT APPLEBAUM and JAMES R. EBERT
Dept. of Earth Sciences
College at Oneonta
Oneonta, New York 13820-4015
The Upper Devonian paleoshoreline of the Catskill clastic wedge in New York State has been interpreted for nearly a century as a complex deltaic sequence (Barrel, 1913, 1914; Chadwick, 1933; Cooper, 1930; Sutton, Bowen and McAlester, 1970; and many others). Friedman and Johnson (1966) envisioned this deltaic complex as a series of coalescing deltaic lobes that progressively filled the Catskill epeiric sea and existed as an uninterrupted deltaic plain from New York to West Virginia. In addition, some geologists believe that such epeiric seas were tideless owing to rapid tidal wave attenuation (Shaw, 1964; and Mazzullo and Friedman, 1975). Others presume that storm (wave) processes were dominant with little or no tidal influence (Dennison, 1985).
This study offers significant departures from these interpretations, by documenting non-deltaic environments with significant tidal influence along the Catskill paleo-shoreline. The purpose of this study (Fig. 1) is to delineate sedimentary environments spanning the non-marine to marine transition in the Upper Devonian Sonyea Group and to test and challenge previous deltaic models of the Sonyea Group (Sutton, et al., 1970). Recent publications have introduced evidence for non-deltaic shoreline environments within the Catskill clastic wedge (Walker and Harms, 1971; 1975; Bridge and Droser, 1985; VanTassel, 1986; also see Seven, 1985, Table 1, p. 83). Others have shown that tidal processes were significant in the Catskill sea (Slingerland, 1986; and Bridge, et al. 1985).
Figure 2 shows the paleogeography of eastern North America during Frasnian-Fammenian time. Paleogeographic reconstructions indicate that the Acadian Mountain range supplied large quantities of sediment westward, allowing a vast alluvial plain to develop. The alluvial plain was fronted by deltaic lobes which prograded westward into the Catskill epeiric sea.

B6: STORM-DOMINATED SHELF AND TIDALLY-INFLUENCED FORESHORE SEDIMENTATION

Oneonta Formation (Genesee Group)
To your left are exposures of fluvial deposits of the Oneonta Formation (Genesee Group). This formation is similar in many aspects to the Lower Walton Fm. (Sonyea Group) included in this study.

The Susquehanna river has incised through the Wells Bridge moraine
The Susquehanna river has incised through the Wells Bridge moraine (right). This moraine served as a dam, which impounded glacial Lake Otego. Up-gradient of the moraine, 300 to 400 feet of lacustrine silts and clays underlie the valley floor. Down-gradient, an outwash terrace can be seen at the rest area (13 mi.).

A sinuous, beaded esker
Immediately after exit 11, a sinuous, beaded esker can be seen at your right (extends for approx. 0.5 miles).

Outcrops of Oneonta Fm. at left.

Glaciofluvial sand & gravel quarry to the left.

Reference marker: Helderberg Bluestone Quarry at end of road
Excellent exposure of the Oneonta Fm. (Genesee Group).

Hummocky cross-stratified sandstones
Hummocky cross-stratified sandstones interbedded with shale of the Glen Aubrey Fm. (Sonyea Gr.).

Glen Aubrey Fm.(right); ball and pillow structures predominate the exposure.

Amalgamated portion of the hummocky cross-stratified facies
Small quarry to the right consists of the amalgamated portion of the hummocky cross-stratified facies of this study (Glen Aubrey Fm.).

STOP 1A: Steele Quarry And Pasture Outcrops Of The Hummocky Cross-Stratified Facies
Location: Scattered outcrops and a small, inactive quarry are located in a cow pasture behind the Steele residence. All stop 1 outcrops can be found in the south-central portion of the Unadilla, New York 7.5 minute quadrangle, located at the intersection of Dunshee Road and Delaware County Route 35. Before visiting the Steele quarry, please ask Mr. and Mrs. Steele for permission to walk on their property. Since stop 1A is on private property, the authors ask that you do not use rock hammers on the outcrops or collect any samples.
Description: The Steele quarry and pasture outcrops (outcrop V) (Fig. 4) are stratigraphically positioned in the Glen Aubrey Formation, and are designated as the amalgamated portion of the hummocky cross-stratified facies. These exposures offer an excellent opportunity to examine hummocks and swales of HCS beds in plan view. The amalgamated portion of the hummocky cross-stratified facies is interpreted as dominantly sandy, storm deposits at or above fair weather wave base (consult text for details). Fossils are sparse and are restricted to coquinite lenses consisting of Sphenotus, Cupularostrum, Platyrachella, fish plates, and plant fragments. Sedimentary structures which cap hummocky cross-stratified beds include wrinkle marks crescentic scour depressions partially filled with very fine sand. These scours commonly exhibit asymmetrical and symmetrical ripples within the depression.
An enigmatic shale unit is found in the center of the quarry. At approximately halfway up in the shale, there is a light colored and differentially weathered horizon which has rather high concentrations of dolomite. Since this shale can not be traced laterally, it is difficult to decipher its stratigraphic context and facies relationships.
At outcrop V in the cow pasture (Fig. 4), excellent hummocky bedforms are present. Within the hummocky cross-stratified beds, climbing ripple cross-lamination are inclined at a steep angle of propagation (Fig. 9). The ripples are slightly asymmetric in the direction of propagation toward the crest of the hummock (from left to right) suggesting that they migrated slightly up the flank. Steep inclination of propagation and the form-concordant style reflects vertical growth of the hummocks with minimal migration. This supports that hummocky cross-stratification formed under high velocity oscillatory flow conditions and rapid deposition rates during storm events.

STOP 1B: Sidney Center Outcrops 1B - 1F
STOP 1B: Open Pit And Field Outcrops Of The Trough Cross-Bedded Facies
Outcrops R and S represent the lowest portion of the trough cross-bedded facies, which sharply overlies the hummocky cross-stratified facies. The trough cross-bedded facies is assignable to the lowest facies unit of the Cattaraugus Magnafacies. Locally, an erosional base defines its base and near base, which is characterized by a coarse lithoclast, shelly, and plant debris lag. Contact relationships are not observable at this stop. The outcrops are positioned within a meter or two above the contact. However, a coarse lithoclast, shelly lag is present at outcrop R. The rhynchenellid, Cupularostrum, and the bivalve, Sphenotus, occur sparsely at this horizon. The sparse marine fauna is the best way to differentiate between the trough cross-bedded facies and the strikingly similar planar-laminated and trough cross-bedded facies (Lower Walton Formation) positioned stratigraphically higher. Trough cross-beds commonly climb at low angles of propagation and interpreted as dunes within tidal inlets within a barrier island/strandplain and tidal creek system. Planar laminated interbeds are interpreted as swash bars within the tidal inlets.
STOP 1C: Logging Trail Outcrop Of The Trough Cross-Bedded Facies
Outcrop D is located approximately 40 feet higher within the trough cross-bedded facies than stop 1B. Trough cross-beds are spectacularly illustrated here owing to well developed differential weathering of the outcrop surface. Trough cross-beds exhibit normally graded, lenticular laminae, which probably reflect sediment supply pulsations induced by tides (Fig. 11). In addition, asymmetrical ripples on troughs commonly oppose the dominant, northerly paleoflow direction of trough cross-beds (Fig. 11 ). These asymmetrical ripples record a subordinate current reversal induced by tides within tidal inlets. Evidence of tidal activity in the Catskill Sea is only sparsely documented in the literature (Ebert, 1987; Walker, 1975; and Bridge and Droser, 1985) and has never been documented from the Sonyea Group.
STOP 1 D: Woodland Outcrop Of The Trough Cross-Bedded Facies
Outcrop K is also assignable to the trough cross-bedded facies. Trough cross-beds are likewise spectacularly illustrated at this outcrop owing to well developed differential weathering of the outcrop surface. Trough cross-beds represent dunes migrating within tidal inlets. These alternate with planar-laminated interbeds, which represent swash bars deposited along the margins of tidal inlets. The trough cross-beds are unidirectional to the north and climb at low angles of propagation. Rare ripple cross-lamination on weathered surfaces is suggestive of current reversals, which offers additional supporting evidence for tidal influence.
STOP 1 E: Bluestone Quarries #4 & #5 Of The Planar-Bedded Facies And The Mottled Mudrock And Sandstone Facies
The planar-bedded facies is sharply overlain at these quarries by the mottled mudrock and sandstone facies. The contact is planar and lacks incision by channels. The planar-bedded facies is extensively quarried for "bluestone" slabs used for sidewalk and construction purposes. Internal lamination within planar-beds is rare, but where it is present, it is often inversely graded. These structures are common on high energy foreshore beach/barrier setting. Also present are abraded arthropod fragments, and highly abraded and highly rounded quartz grains. The arthropod fragments may be either ostracods or trilobites. Near the upper contact of the planar-bedded facies, an association Skolithos linearis, Barroisella campbelli, and delicate plant leaves and stems strengthens a beach (foreshore) interpretation for the planar-bedded facies. Barroisella was an infaunal burrower with a long, siphon-like peduncle and lived with its long axis vertical (Boucot, 1981). It probably lived in intertidal creeks and tidal flats in the Sonyea Group.
The mottled mudrock and sandstone facies stratigraphically above has an association of abundant fish debris of Bothriolepis with Barroisella and Skolithos, occurring stratigraphically above foreshore beach deposits of the planar-bedded facies, argues in favor of brackish water conditions. The mottled mudrock and sandstone facies may represent tidal creek deposits.
Stop 1F (Optional): Bluestone Quarry #1/Transition Of Trough Cross-Bedded Facies With The Overlying Planar-Bedded Facies
Bluestone quarry #1 occurs near the gradational contact between the trough cross-bedded facies and the planar-bedded facies. Planar-bedding dominates while trough cross-bedding is rare. The purpose for visiting this outcrop is to establish the contact relationship and to have an opportunity to collect plant fossils. Fossils of carbonized and pyritized plant stems, branches, logs, and bark can be readily collected at this location. Parting lineations and aligned plant fragments are abundant, which represents a strong onshore/offshore subtidal flow pattern.

Break For Lunch

Exposures of the Triangle Fm. (Sonyea Group)
Exposures of the Triangle Fm. (Sonyea Group) consist of hummocky cross-stratified sandstone interbedded with shale.

STOP 2: Hummocky Cross-Stratified Facies. Triangle Fm(?).
Three outcrops afford ample opportunity to examine storm deposits. We will concentrate most on the largest exposure directly south of the eastbound lanes of Interstate 88. Storm beds, numerous soft-sediment deformation structures of variable scale, bioclastic mudstones and sandstones, and listric truncation surfaces are most easily identifiable at the exposure.
Please be extremely careful not to go out on the highway as this spot has limited sight distance for drivers. Also, vehicles are accelerating up the onramp onto the primary lanes. Please be alert at all times while at this stop. You may cross over to examine the middle outcrop north of the eastbound lanes. Be absolutely sure there are no oncoming cars as far as you can see down the lanes and around the bend before you cross the road. Vehicles are moving faster than they appear but if you are careful then there is plenty of time to cross. Bedding planes are exposed at the very top of the outcrop displaying wave ripples and oriented fossils. They can be reached by carefully ascending the east end of the outcrop at the large culvert that passes under the road. Note also the numerous bedding surfaces with wave (?)or current(?) oriented Mucrospirifers and Tentaculites. East of the culvert are large slabs weathered out of the outcrop that contain numerous fossils and sedimentary structures. Collect all you wish from these loose slabs, but please do not collect in situ fossils or structures as ongoing research is continuing at this time. Please do not disturb any bedrock in place that has elevation or benchmark data recorded on it. These are reference markers for future study and should not be disturbed.
As we work our way up the large exposure, note the changes in lithology. Is the sequence fining or coarsening upward? What about the coarsest sandstone beds? Do they thicken upward over the entire vertical sequence or are there no discernible trends? Notice the slump scars (?) and what's directly above them. Could loading of several storm-deposited decimeter thick sandstone beds above the mudstone have contributed to the slump, or is some other mechanism warranted here such as seismic shaking (see discussion earlier by Bishuk, this paper). Are there any channel forms? We will try to answer these questions at the outcrop.
Note the variability in the morphology of the soft-sediment features. Relative size, orientation, internal stratification, and depth of penetration into underlying beds all vary throughout the section. Does there appear to be a correlation between the size of pillows and the thickness of the overlying sandstones? Are these all just balls and pillows? Consider the possibility of load casts, foundered ripples, and channel forms. Interpretation of these structures at this locality has been a source of lively discussion among the authors. Much work remains concerning the genesis of these sandstones.
Fossil coquinites and bioclastic mudstones are common at the base of storm layers, i.e. very fine to fine sublitharenites. This gives way to planar cross stratification, wave ripples, and thin mudstones with extensive bioturbation at the top of most sequences. These deposits are interpreted as tempestites by Applebaum (in prep.). Internal morphologies vary from one storm bed to another. For a recent discussion of vertical stratification sequences in storm-deposited beds see Myrow and Southard (1991).

STOP 3A: Stream Gorge Exposure Of The HCS Facies, Glen Aubrey Fm.(?)
The exposures in the stream gorge south of Route 206 contain massive bedded sandstones, amalgamated sequences of balls and pillows, and most notably several key horizons of calcareous bioclastic conglomerates that may prove useful as lithostratigraphic or biostratigraphic "key beds". These shell beds are undoubtedly thanatocoenose assemblages and contain mostly crinoid columnals, brachiopods, gastropods, and branching bryozoans.
Numerous erosional surfaces within shell beds indicate amalgamation. Numerous reoriented geopetal structures (e.g. mud-filled gastropoda) suggest reworking of bioclastic materials by storms under waning flow conditions during the closing phases of the individual storm event. Fine mud resuspended by weak oscillatory wave currents settles out into areas of shelter porosity (underneath brachiopoda valves or inside Bellerophon chambers, see Figure 23). Similar fabrics have been documented by Kreisa and Bambach (1982).

STOP 3B: Hummocky Cross-Stratified Facies. Glen Aubrey Fm(?)
This stop has some interesting features on the south side of the road. Of particular note are the high angle dips on some of the sandstone beds. Are these slump structures or channel forms? At the present time a definitive interpretation is unavailable. We welcome any suggestions. Surprisingly puzzling is the outcrop just north of the road, which contains no such distortion of bedding with all horizontal and undisturbed stratification. Can you explain the sudden change in attitude of the bedding over such a small distance, i.e. 10 meters?

STOP 4A: HCS Facies And Dark Gray Shale Facies. Glen Aubrey Fm
Location: A huge exposure of the hummocky cross-stratified facies and dark gray shale facies can be seen on both sides of Route 8 located approximately 1 mile south of I-88 off-ramp.
Description: At this outcrop, we will look primarily at the dark gray shale, facies, which is found as three interbeds within the hummocky cross-stratified facies. The dark gray, facies records three brief transgressive periods, which represent deposition on deeper portions of the shelf. The hummocky cross-stratified facies represents storm deposits within storm base, and is similar here in many aspects to stops 2 and 3. The dark gray shale, facies is characterized by dark gray shale, a complete absence of invertebrates and biogenic structures, and locally abundant, listric truncation surfaces. The listric geometry of the truncation surfaces is consistent with submarine gravity-slide structures. The truncations are sharp and regular without any obvious local channels or erosional irregularities, which is best explained by shear rather than current scour. The rotational slumps were probably triggered by storm events or overloading causing liquefaction and foundering of the sediment.

STOP 4B. Amalgamated Portion Of The HCS Facies, Thorpe Road.
The sharp, scoured and loaded contact in the middle of the outcrop is interpreted as the contact between lower shoreface deposits (amalgamated hummocky cross-stratified facies-above fair weather wave base) and shelf deposits (hummocky cross-stratified facies-below fair weather wave base and above storm wave base). The predominance of fine sand sublitharenite above this contact, and a marked upward decrease in fauna suggest that the amalgamated hummocky cross-stratified portion of this facies occupies the lower shoreface and indicates increasing environmental stress associated with the nearshore. Siltstone and shale interbeds are rarely preserved, indicating that waves or currents (e.g., longshore-, tidal-, and storm-driven) had effectively. winnowed the fine fraction. Hummocky cross-stratification is the predominant structure in all sandstone beds at the outcrop. The top surface of the outcrop displays excellent HCS beds in plan view and a variety of biogenic and sedimentary structures which cap HCS beds. Some of the observable features include wave ripples exhibiting chaotic patterns, asymmetrical ripples with transverse ribs, conglomerate sheets consisting of flat shale intraclasts, paired vertical burrows of Arenicolites, and "figure 8"-shaped burrow of unknown ichnogenera. To reach the top of the outcrop, please walk around to the extreme right-hand side of the outcrop.
Near the base of the outcrop, an unusual interbed of grain-supported conglomerate grades to fine sand sublitharenite. The conglomerate is the coarsest unit found in the study area. Conglomeratic clasts are subrounded, with an abundance of siltstone and shale clast lithologies. These clasts commonly have Paleozoic weathering rinds. Other components include fish fragments, pockets of diagenetic galena, and plant debris occasionally replaced by galena. Graded bedding is the predominant structure consisting of alternating coarse sand and fine sand sublitharenite. Interpretation of this horizon is still pending, although it is suspected that it is a storm-generated deposit.

STOP 5. Sidney Mountain Bluestone Quarry
Planar-Bedded Facies, Mottled Mudrock And Sandstone Facies, Planar-Laminated And Trough Crossbedded Redbed Facies, And The Hummocky Cross-Stratified Facies
Location: From the gate described above in the road log, proceed on foot on dirt road for 200 meters. Walk around left side of quarry storage shed. Road will lead to the bottom of the quarry at its northern-most end. Each facies noted above can readily be seen by traversing back toward the south along the east wall of the quarry. Proceed with caution while walking on the quarry grounds. The terrain is rough and there is an open pit.
Description: Sidney Mountain quarry has the most complicated stratigraphy in the study area and exhibits a multitude of sedimentary features. As a result of its complexity, we direct you to the sections on planar-bedded facies, mottled mudrock and sandstone facies, and hummocky cross-stratified facies (especially Fig. 7).

Richard H. April, Editor
Field Trip Guidebook
Hamilton, NY 13346
Published by the New York State Geological Association.
Additional copies may be obtained from the permanent Executive Secretary, James F. Olmstead, Center for Earth and Environmental Science, State University of New York, College at Plattsburgh, Plattsburgh, New York 12901.
Step out onto the Planet.
Draw a circle a hundred feet round.
Inside the circle are
300 things nobody understands, and, maybe
nobody's ever really seen.
How many can you find?
Lew Welch

A1: THE TRENTON - UTICA PROBLEM REVISITED: NEW OBSERVATIONS AND IDEAS
Gordon C. Baird
Dept of Geosciences, SUNY Fredonia
Fredonia, NY 14063
Carlton E. Brett and David Lehmann
Dept. of Geological Sciences, University of Rochester
Rochester, NY 14627
The Middle to Upper Ordovician Trenton Limestone and Middle to Upper Ordovician black (Utica-type) shale which overlies it in New York State and Southern Ontario have been of considerable interest to geologists since the time of James Hall. This attention is due to the paleontological richness of the Trenton carbonates and early recognition of the facies equivalency of part of the Trenton with black shale deposits in the Mohawk Valley. More recently, heightened interest in Trenton-Utica stratigraphy, sedimentology, paleoecology, and tectonic processes reflects recognition that these sediments are synorogenic. The closely associated Taconic Orogeny represents an arc collision event involving subduction-related emplacement (overthrusting) of an accretionary prism (Taconic Allochthon) over the margin of the Laurentia craton. This emplacement was followed by orogenesis associated with collision, suturing, and uplift of the Vermontia Terrane (Bird and Dewey, 1970; Rowley and Kidd, 1981; Lash, 1988). This paleosetting is believed to be analogous to the present day subduction of the Australian Sahul Shelf under the Banda Arc with the Taconic basin correlating to the foredeep south of Timor. In this context, the Trenton to Utica transition records the collapse of a cratonic platform owing to subduction and thrust load-related down-bending of the craton as the orogeny proceeded. Evidence for this down buckling is manifest in the Middle-Upper Ordovician succession in central and eastern New York as an upward- and eastward facies change from carbonate platform deposits to basinal facies.. Furthermore, numerous normal faults cross-cut the Trenton, which are believed to have been active mainly as synthetic (down to the east) and antithetic (down to the west) displacements reflecting lithospheric responses to subduction (Bradley and Kidd, 1991). Many of these faults are believed to have been active during the tectonic foundering of the Trenton shelf, resulting in a complex "patchwork" stratigraphy for upper Trenton and lower "Utica" units in the Mohawk Valley (see Cisne and Rabe, 1978; Cisne, et.al., 1982; Bradley and Kidd, 1991).
Ruedemann (1925), Ruedemann and Chadwick (1935), and Kay (1937, 1953) mapped Trenton and Utica deposits across this region and recognized that uppermost Trenton units (Rust, Steuben, and Hillier limestones) progressively disappeared to the east and southeast of Lowville, NY Medial Trenton strata (Denmark Limestone) distinctly grade from richly fossiliferous carbonates at Trenton Falls (Poland and Russia members) through a belt of fossil-poor thin-bedded calcilutite facies (Dolgeville Member) to predominantly dark gray or black fissile Utica-type shale (Canajoharie Shale) near Canajoharie, New York. Lower Trenton units (Napanee, King's Falls, Sugar River Formations) were observed to remain fossil-rich across central New York. However, there is an eastward thinning of these lower strata east of Dolgeville, NY, possibly due to submarine erosion. West of Canajoharie, NY the Trenton Limestone is locally missing (see Kay, 1953; Fisher, 1977; Cisne, and Rabe, 1978).
In two important publications, Cisne and Rabe (1978); and Cisne et al. (1982), presented results of highly refined paleoecologic work on Trenton and Canajoharie deposits using volcanic ashes (metabentonites) as correlation isochrons (Figure 1). In so doing, they were able to subdivide the Trenton into thin, time-constrained divisions which could be followed eastward into black shale. Quantitative gradient analysis of fossil associations indicated that this was no steady eastward-sloping ramp; normal faults were believed to have been active in latest Trenton time such that a horst and graben topography was developed and submarine fault scarps existed locally (Cisne and Rabe, 1982).
Controversies concerning Trenton, Canajoharie, and Utica stratigraphy in New York arose early in the study of these units. Although some divisions can be correlated over long distances, abrupt facies changes, losses of units, and appearances of units over small distances have long been noted (see discussions in Ruedemann, 1925; Ruedemann and Chadwick, 1935; Kay, 1937, 1953; Cisne, et al., 1982; Titus, 1986, 1988). The most prominent problem involves Trenton and lower Utica Shale stratigraphy in the interval between Trenton Falls and Middleville, a 16 km wide region northeast of Utica characterized by thick surficial cover and incomplete sections. Another problem is the meaning of sharp lithologic contacts in sections where bioclastic Trenton carbonates are abruptly overlain by dark argillaceous strata (Canajoharie Shale, Utica Shale) or by sparsely fossiliferous ribbon limestones (Dolgeville facies). The presence of such contacts has long been noted, but there is disagreement concerning their extent, age, and significance (see discussions in Kay, 1953; Riva, 1969; Fisher, 1977, 1979; Cisne et.al., 1982; Titus, 1990). Very recently, parts of the metabentonite correlation scheme of Cisne and Rabe (1978) have been called into question owing to new "fingerprinting" correlation techniques for ash identification. This problem, coupled with the unstable existing stratigraphies of Kay (1953), Fisher (1977), Cisne et al.(1982), and Titus (1990), poses the need for continued field study of these rocks but with the application of new approaches and perspectives.
The interest of the present authors of the Trenton-Utica problem stems both from our interest in the relationships of black shales in foreland basins to surrounding facies and from our use of stratigraphic event-horizons in establishing refined correlations in the Silurian and Devonian as well as for Upper Ordovician strata of Ontario and north-central New York. Important to this approach is the recognition of sedimentary cycles of varying magnitude in these younger deposits which owe their origin to eustatic sea level changes (Brett and Baird, 1985; Brett et al., 1990b ). Also relevant to Trenton mapping is the discovery of widespread submarine discontinuities of varying magnitude which define mappable stratigraphic packages of great lateral extent (Brett and Baird, 1986a; Brett et al., 1990a, b). It is our goal to define, firstly, the widespread major discontinuities both within and bounding the Trenton, Canajoharie, and Utica, and secondly, the sedimentary cycles and distinctive cycle-capping condensed units within these large discontinuity bounded packages. Preliminary results of this work are presented below.
We are particularly attracted to the sharp erosional bases of the Ordovician black shales. Our work on Late Ordovician, Silurian, and Devonian black shale-roofed erosions contact shows that they reflect erosional processes occurring predominantly under basinal conditions of prevailing near-anoxia (Baird and Brett, 1986a, b; Baird et al., 1988; Baird and Brett, 1990; Lehmann and Brett, 1991a, b). Preliminary work on Dolgeville, Canajoharie, and Utica discontinuities is presented herein; it shows that these contacts are mappable and significant. A very large and widespread discontinuity herein informally designated the "Sub-Utica Disconformity" may be an Ordovician analog of an erosional overlap surface which floors Middle and Late Devonian black shale deposits across numerous eastern states.

A1: THE TRENTON - UTICA PROBLEM REVISITED: NEW OBSERVATIONS AND IDEAS

STOP 1. West Canada Creek, Prospect:
Slump folds and obrution deposits in the Rust Member, Denley Limestone.
A nearly continuous, although faulted exposure, of middle and upper Trenton strata crops out in the West Canada Creek gorge from the village of Trenton Falls to the Prospect Dam (approximately 3.5 km of exposure). At this stop, we will examine the upper 15 m of Rust bioclastic limestones and the lower 5 m of Steuben calcarenites. A number of interesting and enigmatic sedimentary and taphonomic features are present in this interval.
Note the prominent slump fold horizon (the "upper disturbed zone" of Prosser and Cummings, 1897) in the upper Rust, approximately 5 m above stream level along the east wall of the gorge. Disturbed strata occur as intermittent pods or lenses. Within lenses, strata are folded, brecciated, and -- in some cases -- over-thrusted. Lenses of disturbed strata are typically bounded by, and merge laterally into, shaley horizons, some of which contain slickensides. Some of these shales form rusty, micaceous recessions in the outcrop; they may be metabentonites. This interplay of ductile and brittle deformation suggests that strata were fairly well lithified when they were deformed (Mehrtens, 1984).
This disturbed zone is clearly continuous from Poland to Remsen, a distance of 12 km. Furthermore, "disturbed" strata occur at approximately the same stratigraphic position from Remsen to Lowville, 45 km to the northwest. This widespread occurrence of upper Rust disturbed strata, suggests that deformation reflects some sort of regional event--probably oversteepening of the Trenton ramp/platform.
The timing and nature of this oversteepening event is problematic. Unlike the slump folds in the uppermost Dolgeville (see Stop 6), these slump folds seem to indicate a down-to-the-east paleoslope (Cisne and Rabe, 1978). Although these slump features are clearly post-depositional, sediment was not completely lithified during deformation. Potentially, water released during compaction of clays accommodated the ductile behavior of the limestone beds; the disturbed zone incorporates a particularly shaley horizon of the Rust. Clearly, water content of the muds, amount of overburden, and angle of slope all played important roles in this slump deformation.
How might this slumping have been influenced by tectonic activity? Cisne et al. (1982) and Mehrtens (1988) have suggested that middle Trenton sediments were deposited in a developing foreland basin in which subsidence was accommodated by movement along the numerous normal faults which are present in the Mohawk Valley region. One such fault, which displaces Trenton strata 35 m, is located 150m upstream of the Prospect Bridge. A narrow gully occupies the surficial position of the fault. In the south wall of the gully, Steuben grainstones crop out. In the north wall of the gully, nodular limestones of the lower Rust are present. The northern exposure also contains abundant slickensides. The fault shows reverse polarity. However, drag folds associated with this fault indicate original normal, down to the east displacement; a net reversal of displacement apparently occurred at a later time (Bradley and Kidd, 1991). Tectonically-induced subsidence could have resulted in an oversteepened platform. Interestingly, the disturbed zone is cross-cut by a number of faults suggesting that either: 1) most motion along these faults occurred after slump folding, or 2) synchronous displacement along these faults -- possibly related to thrust loading -- resulted in widespread regional slumping.
Alternatively, Titus (1986) suggests that upper Denley (Rust) to Steuben deposition reflects upbuckling of the western Adirondack Arch region. In this scenario, oversteepening could accompany the basin modification. However, down-to-the-east slump features would suggest that the axis of uplift was to the west of Prospect
Waltherian relationships suggest that the Rust strata at this outcrop represent deposition below normal wave base but possibly not below storm wave base. Lower Rust strata above High Falls at Trenton Falls contain wave ripple marks, while interference ripple marks and hummocky cross stratification occur in the Steuben grainstones at Cincinnati Creek (4 km to the northwest of here). Thus upper Rust strata are conformably bracketed by deposits representing storm-dominated shelf and wave base settings. Airy wave theory analysis of ripple marks of this stratigraphic interval at Booneville (25 km to the northwest) suggests sediment was deposited in water depths of between 1 and 27 m at that locality.
The occurrence of a diverse epibenthos and ichnofauna suggests well oxygenated seafloor and substrate conditions. The nodular bioclastic upper Rust Member contains abundant specimens of the brachiopods Rafinesquina deltoidea, and Platystrophia sp., the bryozoan Prasopora orientalis, and echinoderm plates. Nodular brachiopod- and trepostome-rich packstones and grainstones are typical Rust lithology. However, a 2 m interval of tabular bedded wackestones to fossiliferous lime mudstones are present below the disturbed zone. These limestones and interbedded shales--a tongue of deeper water carbonates, approaching Dolgeville facies -- contain a distinctly different fossil fauna dominated by fenestrate and small ramose trepostome bryozoans, crinoids and the trilobites Isotelus and Ceraurus. These beds, probably correlative with the famed Rust Farm quarry beds of Walcott (1875a, b, c; 1876; 1881), contain abundant ceraurid trilobites at some localities. Brachiopods are much less common than in typical Rust strata. These tabular Rust strata include obrution deposits containing beautifully preserved specimens of Glyptocrinus and Ectenocrinus. These crinoids occur in both carbonate and siliciclastic mud tempestites/turbidites. Upright crinoid stems, up to 8 cm in length, attest to the severity of these sedimentation events.

STOP 2. Ninemile Creek, South Trenton
Disconformity (regional composite unconformity) capping Steuben Limestone and flooring Utica Shale.
At this stop, we will examine a composite unconformity -- the Thruway and Honey Hill discontinuities are superposed here -- which separates Trenton carbonates from overlying Utica strata. This is the only outcrop between Frenchville (15 km to the northwest) and the Norway-Middleville area (15 km to the southeast) where the contact between Trenton carbonates and overlying siliciclastics (in this case, the upper portion of the Utica Shale) can actually be seen; near Holland Patent (2 km to the northwest), a mineralized Steuben top surface can be seen on this same creek, but the basal 0.5 m of Utica Shale is poorly exposed. Surprisingly, although the Holland Patent stream section is commonly cited, the South Trenton section is not mentioned in most earlier reports--most notably Kay, 1953.
The South Trenton section results from a broad anticlinal fold which brings the Steuben Limestone up into view for a distance of 100 m along this stream; this fold is exposed 500 m downstream (west) of the private road bridge over the creek. Three beds (totaling 0.75 m) of Steuben are exposed at the breached fold axis, and over 10 m of Utica Shale are exposed in the stop vicinity.
Dark gray packstone facies of the Steuben is overlain by a 35 cm-thick interval of very dark gray bioturbated wackestone, rich in phosphatic nodules and small rod-like phosphatic bioclasts which forms the limestone bench above water on the creek bank. This is, in turn, overlain by a phosphate-cemented corrosion surface which is distinctly pitted and which contains infillings of Utica Shale and phosphatic debris in depressions between knobs and raised bosses. Locally, a 2 cm-thick micritic ledge is developed along the corrosion surface; it is distinctly perforated, roofing a horizontal crevice space which is filled with phosphatic lag debris. Note the complex pattern of burrow-infilling "let down" of lag debris into and under this uppermost Steuben carbonate bed. Resting on the mineralized surface is black laminated Utica Shale which yields the lower Upper Ordovician graptolite Climacograptus pygmaeus. At Stops 4, 5, and 6 (to the southeast), we will also view Utica Shale over the Thruway discontinuity, but in these latter sections, both the underlying carbonates and the overlying shales are distinctly older. At Frenchville (to the northwest), the Steuben carbonates are overlain by turbiditic siltstones and shales of the Frankfort Formation. In this respect, the South Trenton exposure offers a unique opportunity to see Utica Shale correlative with strata of the type section (Utica) in contact with underlying carbonates. Furthermore, these contact sections illustrate a pattern of northwestward overlap of black muds which continues from Canajoharie to near Toronto, Ontario: progressively younger siliciclastics disconformably overlie progressively younger carbonates (Lehmann and Brett, 1991a).
We interpret the contact displayed at this stop as a corrasional discontinuity produced by combined processes of corrosion and abrasion under conditions of sediment-starvation and dysoxic to anoxic bottom waters. Unconformities of this type typically underlie black shales in the Appalachian foreland basin; sediment-starvation, episodic impingement of deeper water current processes, carbonate undersaturation of bottom waters, and low pH conditions are all believed to contribute to the corrasion process (see Baird and Brett, 1990 for overview). Lag debris produced from the corrasion process consists of insoluble grains of pyrite, phosphate, and quartz. Middle and Upper Ordovician lags of this type are mainly composed of phosphatic nodules and bioclasts.

Pass Strumlock Road.
The furthest southeastern exposure of limestones of the Rust Member (Denley Limestone) occur along a small stream near this road.

STOP 3. Rathbun Brook: Key beds of the Medial Trenton succession.
We will examine bed succession from the top of the Poland Member, through a complete section of our informal Wolf Hollow division, to the lowest 3.5 meters of our Brayton Corners division. Above these strata is a 10 m-thick interval of concealed strata, which begins near the closed meat packing plant. This is one of the most critical and enigmatic sections with regard to the problems of southeastward disappearance of the upper Denley (Rust) strata, thickening of Dolgeville facies, and appearance of lower/middle Utica beds.
Kay's (1953) Poland- Russia boundary on this creek is difficult to locate, as it is on several other creeks; he describes 33 m of "Denmark" at this section of which approximately half is Poland Member (which we will not examine) and half is Russia. We designate the base of Kay's (1953) Russia Member (and our Wolf Hollow division) as the base of a prominent 0.2 m-thick bioturbated packstone layer, herein designated the North Gage Road bed, which holds up a small waterfall on this creek and which will also be seen at Stop 4. This bed is approximately 12.5 m above the top of the Sugar River Limestone.
Above the North Gage Road bed is a 3.5 m interval of thin bedded, tabular to slightly nodular calcilutite beds which is, in turn, succeeded by a thick interval of nodular to massive shaly wackestone and lime mudstone which displays only weak bedding at many levels. This 15 m succession is rich in steinkems of Geisenoceras, which are conspicuous on numerous bedding surfaces. Other common taxa include the trilobites Flexicalymene and Isotelus, the bryozoan Prasopora, and pelmatozoan debris. Two main zones of strongly nodular limestones in this interval are separated by more tabular-bedded calcilutites (Figures 2, 6); These intervals of nearly non-bedded Russia seem to correlate to two thinner massive intervals at City Brook (Stop 4) and correspond to times of sediment-starvation which produced a distinctive nodular, cephalopod-rich facies (cephalopodenkalk) that is thin (stratigraphically condensed) relative to correlative deposits.
Upstream from North Gage Road, nodular deposits give way to tabular bedded calcisiltites and calcarenites which display sharp bases, some with sole marks. This 3.5 m succession, best developed near the fork in the creek below the abandoned meat packing plant, is also characterized by nodular to sandy phosphorite concentrations both at its base and at higher levels. At its base is an irregular knobby contact overlain by a bioclastic debris layer yielding a profusion of nautiloid steinkems as well as abundant phosphatic grains; this bed, in turn, is succeeded by a grainstone layer. This contact marks a submarine erosion surface that correlates to a corrasion surface at City Brook that Kay (1953) designated as the Poland-Russia boundary on that creek (Figure 3).
Herein, the strata between the top of the North Gage Road bed and the base of the 3.5 m thick calcisiltite/calcarenite interval are informally referred to as the Wolf Hollow division of the Russia Member (for the excellent exposure of strata which we will see at that creek), and the overlying 3.5 m interval is referred to as the Brayton Corners division. The Wolf Hollow beds are lithologically distinct and are roughly correlative with the lower 3/4 of Kay's (1953) Russia Member (Figures 2, 6, 7).
The phosphate-bearing, grainstone-rich interval (Brayton Corners division) capping the Wolf Hollow seen here is apparently the upslope facies equivalent of ribbon limestone deposits (upper Dolgeville tongue) which we will see at City Brook (Stop 4). The Brayton Corners division expands upslope to 6 or 7 m of tabular-bedded mixed grainstone-calcilutite facies at Trenton Falls and near Gravesville. In that region, the grainstones are overlain by a 3-6 m interval of thin calcilutites which we refer to as the High Falls Tongue of the Dolgeville Member and which constitute the uppermost Russia succession of Kay (1953). Thus, the Brayton Corners beds appear to be relatively condensed and grade to turbiditic ribbon carbonates (upper Dolgeville tongue) downslope and stratigraphically upwards (High Falls Tongue of the Dolgeville Member) (Figures 2, 6).
Above the critical 10 m covered interval is a 20 m-thick succession of lower/middle Utica black shale with widely spaced micritic beds yielding the graptolites Dicranograptus nicholsonii and C. typicallis. No Rust or Steuben lithology is observed. For a full discussion of the problematic southeastward disappearance of upper Trenton deposits as well as the southeastward appearance of thick Dolgeville and lower Utica divisions, the reader is referred to the text.

The City Brook bed caps the falls on the north side of the road.
The type section for the Rathbun Member of the Sugar River Limestone is exposed in the face of the falls.

Road forks; stay to the right.
The left fork leads to lower portion of the section-Little Falls Dolostone, Black River Group, and the lower Trenton Group--on Wolf Hollow Creek. However, the landowner for this stream section does not allow people on her property.

STOP 4. Wolf Hollow Creek (City Brook), Old City
Condensation of Medial Trenton strata.
We will walk up the creek from the bridge below the Amish farm to examine, in ascending order: the uppermost Sugar River Limestone (Rathbun Member) and the Poland Member, the Wolf Hollow division, and the upper tongue of the Dolgeville Member of the Denley Limestone.
The lowest strata which we will examine are the massive calcarenites of the Rathbun Member of the Sugar River Limestone. Note the large domal bryozoans, Prasopora, in the lowest strata of the Rathbun Member. The Rathbun calcarenites are dramatically overlain by the "Trocholites Bed" of Kay (1937), which is the base of the Poland Member. The Trocholites Bed is herein designated the City Brook bed for the excellent bedding exposures in this interval above the road crossing on this creek. The nautiloid Trocholites is not sufficiently common for that name to have much meaning, and an alternative bed name is advanced here. This unit is widespread, marking the base of the Poland Member from the Lowville area (Chenowith, 1952) to the vicinity of Kast Bridge south of Middleville. At Wolf Hollow Creek this bed is 0.7 m thick, and it is expressed as nodular, intensely bioturbated shaly wackestone-packstone facies which is extremely rich in orthoconic nautiloid and endocerid steinkerns as well as the trilobites Flexicalymene and Isotelus which are sometimes complete. A thin pelmatozoan packstone layer capping the condensed City Brook bed at this creek appears to be coextensive with a submarine discontinuity which oversteps the City Brook bed between the Kast Bridge area and Little Falls. This discontinuity may further correlate with a corrosion surface flooring the Canajoharie Shale at Canajoharie Creek and at a small stream southeast of Amsterdam.
Poland and Wolf Hollow deposits on this creek are represented by a stratigraphically condensed section which is much thinner than that developed at Rathbun Brook (Figures 2, 6). Again, at this section, the North Gage Road bed is identifiable as a 0.2 m compact, nodular limestone. This condensed interval is disconformably overlain by the sparsely fossiliferous ribbon carbonate facies of the Dolgeville Member of which only the lower 8 m are exposed at this section; we will see the top of the Dolgeville at Stops 5 and 6. Careful mapping of middle Trenton beds shows that the Poland-through-Wolf Hollow interval of the Trenton Falls section thins negligibly from approximately 32 m in that area to 31 m at Rathbun Brook; however this interval thins dramatically from Rathbun Brook to City Brook, where only 15 m of section is present. Most of this southeastward thinning occurs in the upper (Wolf Hollow division) part of the section (Figures 2, 6); 15 m of nodular, cephalopod-rich wackestone at Rathbun Brook thin to 5.5 m at the present locality. Within the Wolf Hollow division, the two zones of nodular facies at Rathbun Creek thin respectively to form two massive nodular ledges which cap waterfalls on Wolf Hollow Creek and are separated by only 0.8 m of tabular calcilutites (Dolgeville facies). These meter thick benches, rich in nautiloid steinkems and trilobite fragments, are an Ordovician expression of condensed cephalopodenkalk facies described from Devonian and younger systems (see Jenkyns, 1971; Tucker, 1973; Wendt and Aigner, 1985; Baird and Brett, 1986a, b).
Kay (1953) first reported the mineralized corrosion (discontinuity) surface which separates the upper nodular carbonate (Wolf Hollow division) from the overlying upper Dolgeville tongue. This conspicuous break, seen to best advantage upstream from our turnaround point, records a period of submarine erosion (and probably also carbonate dissolution) on the seafloor prior to deposition of Dolgeville sediment. The association of this break with condensed underlying facies is no surprise; extremely slow rates of sediment accumulation are often exceeded by rates of sediment removal by winnowing and dissolution. We saw this discontinuity in a more subtle development above the nodular interval at Rathbun Brook (Stop 3) where sediment-removal was apparently less severe. Still further west, at Trenton Falls, the top of the nodular interval is conformable with overlying beds. Preliminary study of sections between City Brook and Little Falls suggests that the condensed nodular beds are overstepped by this erosion surface towards the southeast such that some of the Wolf Hollow interval is missing in the latter area (Figures 2, 6, 7).
Kay (1953) correlated his Poland-Russia boundary at Rathbun Brook (near our North Gage Road bed position on that creek) with the corrosion surface level on City Brook. This resulted in the "abrupt facies change" of nodular Russia to Dolgeville between the two sections. Our recognition of the North Gage Road bed on Wolf Hollow Creek as well as successful matching of the nodular condensed limestone intervals (Figures 2, 6) provides a more palatable stratigraphic match between these sections, and it eliminates the disjunctive facies change. On Wolf Hollow Creek, the Poland interval, herein redefined, encompasses a 9.5 m thick interval, dominated by tabular-to-wavy bedded micrite beds between the base of the City Brook bed and the base of the North Gage Road bed which caps a low waterfall on this creek. The Wolf Hollow division includes the remaining 5.5 m of Trenton section up to the discontinuity surface.
The overlying Dolgeville Member is composed of tabular bedded ribbon carbonate which alternates with very dark gray to essentially black shales. The Dolgeville strata yield a sparse fauna including graptolites and the small trilobites Flexicalymene and Triarthrus. We agree with other workers that this is a basin slope facies characterized by carbonate turbidites and an impoverished dysoxic fauna. Some beds show distinctive current markings (sole marks, ripple marks, and aligned fossils). Soft-sediment failure is represented by ball-and-pillow deformation at several levels.
The age of this Dolgeville sequence and its relationship to the Trenton Limestone is, in part, problematic (see text). The basal 1.5 m contains beds rich in nodular, sand-sized, phosphatic debris. This interval appears to be the downslope expression of the Brayton Corners division which we saw at Rathbun Brook and which also crops out at Trenton Falls (Figures 2, 6). However, higher, non-phosphatic Dolgeville deposits at Wolf Hollow Creek and near Middleville may correlate to the High Falls tongue of the Dolgeville at Trenton Falls and/or possibly to the Rust Member (see discussion in text).

Vuggy carbonates of the Little Falls Dolostone
Vuggy carbonates of the Little Falls Dolostone crop out on the left side of the road. Many of these vugs contain doubly-terminated quartz crystal--the famed Herkimer Diamonds.

Note the "Ace of Diamonds" Herkimer Diamond quarry and campground.
We will pass another Herkimer Diamond quarry (Herkimer Development Corp.) over the next mile.

Cross West Canada Creek on Kast Bridge.

Cross North Creek.

Kay's Poland Mbr. of the Denley Limestone
Kay's Poland Mbr. of the Denley Limestone crops out along North Creek to the right.

STOP 5. Unnamed branch of North Creek, Eatonville
Upper Dolgeville-lower/middle Utica Shale contact.
We will proceed to the falls above the lower end of the creek section and examine the top 4 to 5 m of the Dolgeville Member, the Dolgeville-lower/middle Utica contact (Thruway discontinuity) and metabentonite (volcanic ash) layers in the lower/middle Utica.
Turbiditic, ribbon limestones of the Dolgeville are visible at the base of the falls and in the downstream bank. In the downstream bank, these beds are of a nearly uniform thickness and spacing, which is typical for large portions of the upper Dolgeville. A low diversity, dysaerobic fauna of graptolites, orthoconic nautiloids, and the trilobite Trianhrus is characteristic of these strata, though diminutive Onnielfa, Rafinesquina, and Flexicalymene can be found in winnowed hash layers in some parts of the Dolgeville. Just below the discontinuity, and extending up to it, is a zone of folded and contorted Dolgeville beds. (Use caution as you ascend the falls; these beds can be slick!) This disturbed zone is seen to better advantage on the New York State Thruway and it is discussed under Stop 6.
The Dolgeville-Utica discontinuity is slightly undulatory here due to effects of differential compaction over beveled limestone beds, and/or, secondary diagenesis along the contact. A lag zone of phosphatic hash overlies this break with subsidiary phosphatic debris layers recurring through the next 10 m of section. Phosphatic debris includes orbiculoid fragments, phosphatic rod-like structures possibly belonging to Sphenothallus, diminutive Onniella, corroded pelmatozoan grains, and comminuted graptolites. On the Thruway and in sections near Middleville and Norway, a spectacular lag of imbricated, corroded ribbon limestone fragments is present on this contact. These clasts display pitted exteriors characteristic of dissolution; partly exhumed in situ limestone beds at the section northeast of Norway display interior crack systems which have been extended and widened by this same process, allowing lag debris to work its way into the cracks.
The lower/middle Utica Shale consists of very hard, laminated shale with thin ribbon limestones and metabentonite layers. Graptolites are common and are spectacularly current-aligned on several bedding planes. Two excellent metabentonites can be examined in the falls; these beds appear as pasty, pale gray layers. New "fingerprinting" techniques, which allow identification of specific ash beds (specific eruption events) as geochemically unique, are presently being applied to these layers in still another approach to working out Trenton-Utica stratigraphy.
The Utica Shale at this section is distinctly older than that observed at Stop 2; the upper beds of this lower/middle Utica strata yield the graptolites Climacograptus typicalis and Dicranograptus nicholsonii whereas the upper Utica Shale at South Trenton contains C. pygmaeus, a distinctly younger graptolite (Kay, 1953; Riva, 1969). This change reflects, in part, the northwestward overlap (termination) of progressively younger Utica beds against the discontinuity surface in that direction. It also reflects the additive merging of the Thruway discontinuity with the younger Honey Hill discontinuity due to erosional overstep (see text: Figures 2, 6, 7).
As indicated earlier, the age of the upper Dolgeville, seen at this section, and at Stops 4, 6, and 7, is problematical with respect to the Trenton Limestone. The lower pan of Dolgeville (perhaps 10 to 13 m) and lower Canajoharie strata can be matched with the Poland Member using graptolites (Kay, 1953). However, the >22 m-thick upper Dolgeville tongue of the Norway-Kast Bridge area clearly overlies the top- Wolf Hollow corrosion surface, hence it cannot be linked with anything older than the Brayton Corners division at Trenton Falls. The great thickness of upper Dolgeville (and upper Canajoharie) strata relative to the upper Russia interval at Trenton Falls and at Gravesville opens the possibility that the upper Dolgeville may be time-equivalent with the Rust Member. This hypothesis remains to be tested.

Cross the mighty Mohawk River.

Thick bedded Dolgeville carbonates crop out on the right (south) side of the highway.

Low outcrops showing Dolgeville and lower/middle Utica strata
Low outcrops showing Dolgeville and lower/middle Utica strata are on the right (south) side of the highway.

Optional STOP 6A. New York Thruway: The Thruway discontinuity
This (along with optional Stops 6B and 6C) will be a relatively brief stop owing to hazardous traffic. We will stay in vehicles and observe outcrop features from van windows. This outcrop exposes essentially the same section as at Stop 5. However, this roadcut is cleaner, more extensive, and much more dramatic. Only the upper succession of Dolgeville strata is visible at this locality. Note that the upper Dolgeville contains densely packed beds of calcilutite and calcisiltite. In this region, top Dolgeville strata are underlain by a middle, shale-rich Dolgeville interval which contains relatively few ribbon carbonate beds. This middle Dolgeville interval, in turn is underlain by a calcilutite-rich lower Dolgeville succession which correlates with the Poland Member and the lower part of the Wolf Hollow division; the base of the Dolgeville however, is quite shaley. This "double paired" pattern of shaley strata giving way to more calcareous strata continues east to the Canajoharie region. On Rat Creek for example, the uppermost Canajoharie Shale is actually a Dolgeville lithology and contains closely spaced ribbon carbonate beds.
Most notable in this roadcut are the numerous folds which are best developed in the top 1.5 m of the Dolgeville. This zone of deformed strata can now be traced for at least 20 km from a small creek northeast of Norway to Nowadaga Creek (north of Newville). Lower Dolgeville beds are also locally deformed, as can be seen on the Thruway approximately 2 km west of Stop 6, but the highest deformed zone is the most conspicuous and persistent.
The cause and timing of this folding is controversial, and it is central to hypotheses concerning the inferred sequence of events associated with the Taconic Orogeny. Fisher (1979) noted that axial planes of these slump folds typically dipped to the east, indicating a down-to-the-west paleoslope, and postulated that the paleoslope reversal was the result of compressional up buckling of the Adirondack Arch. Work by Bradley and Kidd (1991) outlining the dynamics of this sort of "flexural extension" largely supports this interpretation. Clearly, a number of features indicate that this deformation is the result of post-depositional slumping. Firstly, although most deformation is ductile, fracturing and brecciation does occur in the deformed zone. Furthermore, even ductily deformed strata contain wedge-shaped fractures suggesting that this sediment was partly lithified. Secondly, most folds incorporate numerous beds.
At West Crum Creek, 5 km to the east of Little Falls, slump features indicate a more complex scenario. At that locality, most slump features indicate a northeastern dipping paleoslope; however, some folds indicate slumping towards the southwest. Perhaps these slump features represent a number of episodes of fault block adjustment. Similarly, directions of fold axes tend to be polydirectional at Nowadaga Creek, suggesting the possibility of multiple deformation events.
Above the folded beds is a sharp horizontal contact marking the change to lower Utica deposits. As we saw at Stop 5 and will see at Stop 7, this is an erosional discontinuity marked by reworked phosphatic lag debris, disseminated pyroclastic material, and localized concentrations of variably corroded, reworked Dolgeville limestone intraclasts. Furthermore, the uppermost micritic ribbons of the Dolgeville are coated by a pyritic crust Because the contact between the Dolgeville and the lower/middle Utica is so well exposed at this locality, we refer to this contact as the "Thruway discontinuity."
The Thruway discontinuity appears to breach many of the underlying folds such that many of the anticlines are "bald headed" structures. This indicates that post-Dolgeville, pre-Utica submarine erosion would have occurred after the folding event. Since we envision the episode of erosion as having taken place during a period of relative sea-level rise and consequent sediment starvation to the region, it is interesting to speculate that the folding event may have been a seismic harbinger of tectonic deepening of the basin. Again, we must note that the relationship of the fold horizon to the upper Trenton Limestone of the Poland-Prospect region is problematic; these folds may link to one the deformed zones in the Rust Member or to Brayton Corners strata (see text, Stop 1).

Optional STOP 6B. New York Thruway: Lower/middle Utica strata.
Along this portion of the roadcut, the lower/middle Utica Shale, which overlies the Dolgeville, is well exposed. As noted at Stop 6A, the contact between the Utica Shale and underlying Dolgeville strata is unconformable. Note, the metabentonite which forms a prominent rusty recession in the outcrop approximately 1.75 m above the base of the Utica. This particular metabentonite was seen at Stop 5 and will be seen at Stop 7. Other thin metabentonites can be seen in this roadcut and also in the "Black Canyon" (Stop 6C). Qualitatively, we have noticed that metabentonites typically are present in condensed intervals.
Also note that the lower/middle Utica strata in this outcrop contains thin, rusty (pyritic?), calcilutites. Locally, the lower/middle Utica succession between the Thruway discontinuity and the Honey Hill discontinuity is crudely divisible into three lithostratigraphic successions: 1) a lower, calcilutite-rich interval, 2) a middle calcilutite-poor, black shale interval, and 3) an upper calcilutite-rich interval.
Finally, note that this outcrop contains numerous small faults. These faults which displace both Dolgeville and overlying Utica strata belong to the Little Falls fault zone. The major fault of this fault zone, the Little Falls fault(> 1 km to the southeast), has a vertical displacement of 155 m (Bradley and Kidd, 1991).

Optional STOP 6C. Little Falls exit, New York Thruway
Utica strata of the "Black Canyon"
As we drive through the "Black Canyon," note the apparently monotonous nature of the Utica black shales. A number of thin metabentonites (which form rusty recessions in the outcrop) are present at this locality. The metabentonites along with graptolite zonation offer key -- yet sometimes controversial -- stratigraphic information for regional correlation of Utica strata (see Cisne and Rabe, 1978; Mitchell and Goldman, 1991).

Drive through the graffiti-enhanced canyon of Precambrian Grenville basement.

STOP 7. East Canada Creek, Dolgeville
Drag-folded Dolgeville and Utica strata.
Along East Canada Creek, below the Dolgeville Dam, the upper 15 m of Dolgeville strata and a large thickness of the overlying shales of the lower/middle Utica are spectacularly exposed in a drag fold along the east side of the creek. This drag fold is associated with the Dolgeville Fault, another of the syntectonic normal faults of the Mohawk Valley region.
Many of the features discussed and seen at Stops 5 and 6 are also readily examined at this outcrop:
1) The upper Dolgeville strata are slump-folded, but, due to the drag folding process, slump folding is not as evident as at Stop 6.
2) The Dolgeville strata are overlain by a 5 cm-thick phosphatic lag which we will sample if the stream level is low.
3) A metabentonite forms a prominent recession in the outcrop approximately 1.5 m above the Dolgeville-Utica contact
4) The lower/middle Utica contains rusty-weathering calcilutites. However, calcilutite beds are less numerous than in lowermost Utica strata at Stop 5. This may be due to distance from a carbonate source, proximity to a siliciclastic source, and accommodation space (subsidence). Alternatively, we may be seeing a slightly lower stratigraphic interval at Dolgeville which is not represented at Stop 5 or is represented by condensed facies in that area.
Well developed fine-grained turbidites CTbcd) are present in the Utica. Winnowed shell lags containing trilobite hash, small brachiopods, and current-aligned graptolites within black shales, however, indicate that not all downslope-directed currents resulted in deposition.

A2: NON-FOSSILIFEROUS AND FOSSIL RICH BEDS IN THE HAMILTON GROUP; INDICATORS OF SEDIMENTATION RATES
David Linsley
Department of Earth and Planetary Science
University of Pittsburgh.
Pittsburgh, PA 15260
Stephanie Christensen, Leah Kittredge, Cathryn Dwyer, and Robert M. Linsley
Hamilton. NY 13346
The Hamilton Group siliciclastic rocks are part of the progradational sequence formed at the onset of the Acadian Orogeny. Mountain building occurred to the east of New York state on a NNE/SSW trend. Paralleling the mountains to the west was the axis of the depositional basin which ran approximately through the Finger Lakes region. This is reflected by the thickening trend of Hamilton Group rocks from west (100 m) to east (1000 m). Throughout most of the Givetian Stage, eastern New York was close to the depositional source. This can be seen in the Albany area and immediately to the south where Hamilton Group equivalent rocks such as the Plattekill and Manorkill Formations preserve evidence of fluvial depositional environments (Willis 1990). To the west of the fluvial facies is the Panther Mountain Formation which contains nearshore marine sandstones which extend to the Unadilla valley area. The Panther Mountain Formation is the eastern equivalent of the Skaneateles and Ludlowville Formations of Central New York. In western New York the Hamilton group is predominantly dark shales and siltstones with rare carbonate units. The dark shales represent environments distant from the depositional source and in deeper water conditions than the sandstones of the Panther Mountain Formation. The rocks of central New York are a mixing and interfingering of the basinal and nearshore marine environments (Fig 1 ).

A2: NON-FOSSILIFEROUS AND FOSSIL RICH BEDS IN THE HAMILTON GROUP; INDICATORS OF SEDIMENTATION RATES

STOP 1. Hoaxie Road Quarry
This coarsening cycle is interpreted to be at the base of the Butternut Member in the Skaneateles Formation. The quarry exhibits the repeated coarsening-upward trend observed at most localities in the Hamilton Group. The rock type at the base of the quarry is shale interlaminated or thinly interbedded with fine siltstone. Close inspection reveals repeated 1-2 cm thick couplets of fine siltstone and shale. The siltstone contains low angle cross laminae and planar laminae. The base of the siltstone units is abrupt and the contact with the shale above is gradational. In the middle part of the exposure the silt beds become thicker (5 cm) and preserve rare articulated crinoid columnals typically on the upper surface of the siltstone beds. No fossil lag deposits are observed at the base of the siltstone beds and fossils are otherwise rare in this part of the outcrop. The upward increase in thickness of the siltstone beds indicates a closer proximity to the source of sediment and an increase in energy conditions on the substrate, both of which reflect the shallowing upward nature of the depositional cycles. The upper part of the outcrop is bioturbated very fine sandstone and contains a normal Hamilton assemblage of bivalves and brachiopods.
Fossils in the lower part of the exposure are rare and when observed are concentrated on single bedding planes. At vertical intervals of 1-2 m discontinuous lenses, meters in width and 1-2 cm in height, contain articulated bivalves, brachiopods, and the crinoids Gilbertsocrinus and Acanthocrinus. The bivalves Leiopteria conradi, Actinodesma erectum and Actinopteria boydi are numerically the most abundant taxa and are all epifaunal, possibly byssally attached forms. The brachiopods Tropidoleptus carinatus and Camarotoechia congregata are associated with the bivalves but are less abundant. The crinoids are articulated and appear to be using the bivalve shells as a substrate. The unusual aspect of these shell beds is that they are not storm accumulations and the fossils are articulated and in life position. Rocks above and below the fossil beds are nearly barren and preserve only rare brachiopods and bivalves.
The presence of small-scale sedimentary structures in fine grained sediments is rare in Hamilton Group rocks in central New York. Infaunal and semi-infaunal organisms disturb the substrate and destroy sedimentary structures. If sedimentation rates are low enough for the organisms to continually rework the sediment, no sedimentary structures will be preserved and the mud and silt layers are homogenized into the bioturbated mudstone commonly observed in Hamilton Group rocks. At this and other localities there is a conspicuous absence of fossils associated with the stratigraphic intervals where sedimentary structures are preserved. An absence of fossils may be explained by rapid deposition rates which create an unstable substrate, by a lack of oxygen, or by non-normal marine salinities. The pycnocline model is applicable in relatively deep water settings; however central New York is closer to the depositional source and in presumably shallow water depths.
An alternate explanation for non-fossiliferous units could be viewed as follows: assuming that the depositional cycles are shallowing up sequences one method of deposition may have been basinal infilling. If sea level is stable and sediment is transported to the basin, progradation of the shoreline will occur. The part of the basin proximal to the shoreline will become infilled with sediment and a shallowing upward depositional sequence will be produced. By this model the muddy siltstones would be less than ten meters below the sandstones. The water depth of the sandstones is equivocal but they are definitely within storm wave base, and given the proximity to the shoreline, probably in less than ten meters water depth.
Brett (1985) has postulated that periods of maximum deposition occur in the middle of the depositional cycles in the siltstone/ mudstones and that while the sandstones are deposited in the shallowest water, they are also periods of low deposition rates. The sandstones are possibly reworked or winnowed over long periods of time. If the siltstones and shales were deposited rapidly this could have created unstable water saturated sediment which would have kept epifaunal or semi-infaunal filter feeders from colonizing the substrate, thus creating non-fossiliferous intervals. However evidence from this locality suggests otherwise due to the presence of rare shell beds with epifaunal bivalves. Furthermore, the centimeter- scale siltstone beds, which should have been a relatively stable substrate, have no fossils associated with the upper surface. This suggests that a factor other than anoxia or substrate instability was preventing the colonization of the substrate by epifaunal benthic organisms.
The proximity of central New York to the fluvial environments in the east suggests that hypo-saline conditions could be a factor in controlling faunal assemblages on the nearshore shelf. The northern end of the Appalachian Basin during the Devonian was a relatively enclosed basin. The uplands created to the east by the Acadian Orogeny were the major source of siliciclastic sediment. Fluvial depositional systems have been identified in Hamilton Group equivalent rocks in eastern New York. Rivers feeding the sediment to the basin may have had the effect of reducing salinity in the shallow, nearshore regions of the basin. If the siltstone/ mudstone intervals were deposited during periods of maximum sedimentary influx, and the position of the ancient shoreline was less than 100 km to the east, it is possible that the nearshore or shallow part of the basin experienced periods of hypo-salinity. During periods of low rainfall normal salinities would return to the nearshore part of the shelf and a normal marine fauna would colonize the substrate. If the sandstones were deposited or reworked during periods of low sedimentary influx this may also have been a time of relatively low rainfall and consequently normal marine salinities.
Fossil evidence in the form of thin lenticular shell beds containing in place articulated bivalves and crinoids suggests episodic colonization of the substrate followed by an abrupt event which preserved the fossils without disruption. The rare fossils, typically Camarotoechia congregata, Trooidoleptus carinatus, Grammysia bisulcata and Pterochaenia fragilis in the intervening layers between shell beds are found on single bedding planes with only Grammysia appearing to be in life position. In the middle part of the outcrop siltstone beds preserve articulated crinoids on the upper surface of the beds. The fossils between the shell beds in the interbedded siltstones and shales are the best indicators of the typical paleoenvironment. Fossils such as Camarotoechia, Tropidoleptus and Grammysia could have been salinity tolerant. Only Grammysia and Pterochaenia are found articulated and in place. The brachiopods could have been transported although they are not found associated with sedimentary lag deposits. The crinoids associated with siltstone layers could have been transported, although not over long distances since they are still articulated. The shell beds contain dominantly bivalves which may have been salinity tolerant (Brower and Osborne 1991) but also contain articulated crinoids which are much less likely to have been salinity tolerant.
The rarity of both fossils and bioturbation in the thinly interbedded siltstones and shales suggests that some factor was preventing colonization of the substrate. Dysoxia has been suggested as a possible factor but the fossils that are present tend to be salinity tolerant species rather than species typical of the deeper water dark shales associated with dysaerobic conditions. When periods of normal marine conditions occur the substrate is apparently rapidly colonized by bivalves, brachiopods and crinoids. These brief periods of colonization are equally rapidly ended by an event which preserves the fauna intact and articulated. The proximity of central New York to the ancient shoreline and accompanying river systems suggests that fresh water flooding of the nearshore shelf may account for some nonfossiliferous intervals in the interbedded silts and shales.

STOP 2: Brookfield West Quarry
This section is tentatively placed as the fourth or uppermost coarsening cycle of the Delphi Station member of the Skaneateles Formation. The lower two meters of section contain 5-20 cm thick interbeds of shale and siltstone. Siltstone beds have an abrupt base and grade upward from planar laminae into small scale, high angle cross laminae. The upper surfaces of some siltstone beds preserve symmetrical ripples. The siltstone units are interpreted to be event beds, probably storm deposits. The absence of infaunal and epifaunal organisms with the related bioturbation is discussed in the section on the Hoxie Road quarry. The shale separating the siltstones is fissile, lacks lamination and contains no fossils with the exception of rare cephalopods.
In the middle of the exposure is a noticeable notch in the quarry wall. Above this the siltstone/ shale interbeds disappear and bioturbated sandstone, with a normal Hamilton faunal assemblage of epifaunal bivalves and brachiopods, is observed. The notch in the quarry wall is a light gray clay, varies in thickness from 0.5-3.0 cm, and is traceable the length of the outcrop. X-ray analysis reveals the presence of illite and chlorite but no expandable clay minerals. The coarse fraction of the clay does contain some euhedral crystals. This bed is tentatively identified as a meta-bentonite .
Ten centimeters below the clay bed is a densely packed fossil-rich zone 1-4 cm thick. This is the first appearance of fossils in the lower part of the quarry. The assemblage is unusual in that it contains the monoplacophoran Cyrtonella and abundant infaunal bivalves, Nuculoidea, Nuculites and Modiella. Infaunal bivalves would not normally be found in a packed shell bed like this since when they die they are already buried. The presence of these shells together indicates that the sediment has been reworked and that this bed may be a sediment-starved omission surface. Phosphate pebbles are found with the shells in this bed which also suggests that the accumulation of shells took place during a depositional hiatus.
This section is somewhat unusual in that it does not follow the typical pattern of a gradual coarsening upward trend. The fossil rich sandstones at the top of the locality appear relatively abruptly following the appearance of the clay bed. Whether there is a tectonic connection between the two events is highly ambiguous.

STOP 3: Bailey Road Quarry
The seventeen meters of section at this locality represent the Pompey Member of the Skaneateles Formation. From the base of the section to the top there is an overall coarsening trend from shale through fine sandstone. Within this coarsening trend there are four, meter-scale coarsening upward units. In the terminology of Bush and Rollins (1984) the entire outcrop would be a fifth order cycle and the smaller coarsening sequences would be sixth order cycles. The base of the smaller cycles is indicated by topographically level areas within the quarry.
The lowest small-scale coarsening cycle is bioturbated shale with abundant, well preserved, articulated bivalves and brachiopods. The bivalve assemblage is dominated by Nuculites oblongata, N. triguiter, Modiella pygmaeaand Paracyclas Iicata. The top of the first cycle grades upward into a packed silty shell bed containing Longispina, Mucrospirifer, and rare septate rugose corals. The second depositional cycle grades upward from a siltstone through a coarse siltstone. The finer grained interval is bioturbated but contains no fossils with the exception of rare cephalopods. The coarser part of the cycle contains a chonetid/Mucrospirifer assemblage. The third cycle is progressively coarser than the first two, grading from mudstone through very fine sandstone. The base is again bioturbated but relatively non-fossiliferous. The top of the cycle is capped by a packed shell bed containing the brachiopod genera Rhipidomella, Pseudoatrypa and Athyris. These brachiopods, particularly Pseodoatrypa, are relatively rare in the rocks of central New York and have been interpreted to represent clear non-turbid water conditions. The fourth cycle is again coarser than the previous three, grading from siltstone to fine sandstone. Brachiopods dominate the fauna though bivalves, particularly Cypricardinea indenta, Paracyclas lirata and Nyassa arguta, are quite abundant. Bryozoa and zoophycus are common in the upper part of the cycle but appear only occasionally below this. Several packed shell beds are located within this cycle. Two are similar to the one capping the third cycle (i.e. dominated by Rhipidomella and Athyris) while several others are dominated by Spirifers and Ambocoelia, with lesser amounts of Chonetes and other organisms
The depositional sequences at this locality provide some clue to sedimentation rates if the assumption is made that fossil preservation potential and biogenic productivity, in terms of shell production, is constant through time. The fossiliferous shaley interval of the lowest cycle can be interpreted to have relatively low sedimentation rates due to the presence of numerous infaunal and epifaunal organisms. The shell bed which caps this interval is a period of low siliciclastic deposition where fossils accumulated gradually through time. Evidence in the form of disarticulated shells suggests that the shell bed was affected by storm events; however, no sedimentary structures are visible to support wholesale transport or reworking of the shells as a lag deposit. The base of the shell bed is gradational with the underlying shale, further supporting an in place formation of the bed. The base of the second cycle is nonfossiliferous yet it is bioturbated. This interval probably represents a period of rapid deposition where epifaunal filter feeders would have had difficulty with an unstable and rapidly aggrading substrate. The absence of infaunal deposit feeding bivalves cannot be easily explained since the presence of bioturbation and rare cephalopods suggests that organisms were present and that fossilization was possible. The upper part of the cycle is coarser grained and preserves abundant brachiopods. This indicates a decrease in sedimentation rates. The third cycle is again non-fossiliferous at the base and is capped by a shell bed containing an unusual assemblage of brachiopods. The Athyris/Pseudoatrypa/Rhioidomella assemblage has been interpreted to represent a shallow, clear water depositional environment. This shell bed represents an absence of siliciclastic deposition. The abundant brachiopods of the fourth cycle again suggest fairly low sedimentation rates, while the shell beds, similar to those of the third cycle, most likely represent periods of non-deposition.

STOP 4. Geer Road Quarry
The nine meters of section at this locality represent the lowermost of the four coarsening upward cycles in the Moscow Formation (Selleck, personal comm.). Grain size ranges from very fine siltstone at the base of the quarry through very fine sand at the top, with most of the coarsening occurring in the upper three meters. The faunal assemblage is dominated by brachiopods (80%) and bivalves (10%) with gastropods, cephalopods, trilobites, bryozoans and crinoids also present.
Fossils are distributed abundantly and fairly uniformly throughout the section; however, flat bedding planes of densely packed shells, predominantly of the brachiopod Chonetes, also occur. In the lower three meters of the section these Chonetes shell beds occur at intervals of 20-25 cm. Above the first three meters Chonetes beds become rare. Orientation of the shells varies between the upper and lower beds. In the lower shell beds Chonetes are found 50% in life position and 50% overturned while in the upper beds 90% of the Chonetes are overturned. In the siltstones between the shell beds different taxa are present in approximately the same ratio as seen on the shell beds, but the density of fossils is much less. No sedimentary structures are visible.
The Chonetes beds may represent storm events during which transported siliciclastic sediment smothered the brachiopods. However, the sedimentary characteristics normally associated with tempestites, such as fining upward sequences or planar or cross laminae, are not visible. The presence of fossils in the sediment between the shell beds suggests that they are not winnowed lag deposits.
A more probable theory is that the shell beds represent periods of non-deposition allowing for the build-up of many shells over time. If the coarsening upward sequence reflects shallowing, the lower shell beds would have been in deeper water than the upper beds. The differing orientations of the Chonetes may then be explained; the lower, deep-water shell beds would have remained relatively unaffected by wave action, allowing half of the brachiopod shells to remain, even after death, in the less stable life position. The Chonetes of the upper shell beds, being in shallower water, would have been 90% overturned into a hydrodynamically stable position.
The most definitive evidence for storm deposited sediments is a 5-8 cm fine to medium grained sand bed located six meters above the base of the quarry. The sand bed has an abrupt base and contains small scale cross and planar laminations. Both shelled fossils and trace fossils are absent from this bed, appearing neither as storm lag deposits nor as colonizers of the post-storm surface. The position of this bed is near the top of the section, in the coarser part of the cycle. Assuming that the cycles represent shallowing upward, this part of the quarry may have been within the influence of storm wave base. The lower, finer grained part of the cycle was likely deposited in deeper water below storm wave base.

STOP 5. English Avenue Quarry
This quarry is situated in the Delphi Station member of the Skaneateles Formation. The gastropod species Bembexia sulcomarginata is abundantly represented at this locality and all specimens are either of the ornamented variety or the intermediate B variety. (See the discussion of Bembexia following the locality 6 description.) They are distributed from the finer grained siltstones at the bottom of the quarry through the coarser material at the top.

STOP 6. Peterboro South (Swamp Road South)
This locality is in the lower part of the Pecksport Member of the Marcellus Formation. The rock type is mudstone with very few sedimentary structures and abundant fossils. The preservation at this locality is quite exceptional for the Hamilton Group in that molluscs have their shells intact and are not preserved as composite molds as at Geer Road. Small amounts of original aragonite may still be found in some shells and the replacement of aragonite by calcite is so fine that the original shell microstructure is still preserved (Carter 1978).
All the specimens of Bembexia sulcomarginata that have been found in this quarry are of the unornamented type. They may be found throughout the entire quarry but are most abundant in the upper surface of the lower quarry face.

STOP 6A. Peterboro North
(no description)

A3: COMPARATIVE SEDIMENTOLOGY OF THE LOWER DEVONIAN MANLIUS FORMATION NEAR HAMILTON, NEW YORK
Robert V. Demicco,
Tim K. Lowenstein,
Binghamton University
The State University of New York,
Binghamton, New York
Kathleen M. Browne
Comparative Sedimentology Laboratory
Rosenstiel School of Marine and Atmospheric Sciences
Miami, Florida
The paleo-environments of ancient sedimentary deposits are diagnosed from the vertical and lateral distribution of elemental rock units (subfacies), characterized principally by their assemblages of sedimentary structures, using analogs established from observations of processes and the sediments in modem depositional environments (the "comparative sedimentology" method of Ginsburg, 1974). Modem shallow marine carbonate environments carry a particularly rich inventory of primary and early diagenetic sedimentary structures, such as current and wave bedforms, trough and tabular cross-stratification, "herring-bone" cross-stratification, flat lamination, wavy and crinkled lamination, thin bedding, stromatolites, thrombolites, mudcracks, sheet cracks, prism cracks, flat pebble gravels, fenestrae, burrows, evaporite minerals, early cements, hardgrounds, caliche crusts, tepee structures, soils, and so on. And most significantly, the stratigraphic record back at least into the Proterozoic is replete with carbonate deposits that delicately preserve these sedimentary structures (see, for example, Ginsburg, 1975; Wilson, 1975; Hardie and Shinn, 1986; Gretzinger, 1989), demonstrating the existence through much of geologic time of environments and environmental processes analogous to those of modem shallow marine carbonate platforms and shelves.
There are other areas of study beyond reconstruction of paleo-environments where the environmental information preserved in the primary sedimentary structures and early diagenetic features of shallow water carbonates is of considerable value, for example, in the fields of paleo-oceanography, paleo-climatology and cyclostratigraphy. In particular, tidal flat facies are unsurpassed "sea level gauges," "tide gauges," and "climate recorders" (Hardie, 1977, p.188-189). An unambiguous record of the position of ancient mean sea level is engraved within the intertidal subfacies of all ancient shallow marine carbonate deposits. And the same intertidal subfacies carry a record, quantitatively determinable, of the tidal range in the depositional environment (cf. Klein, 1971). At the same time, the subtidal subfacies record the ambient and storm wave energy levels across the buildup, and this information in turn reflects, at least in a qualitative way, the prevailing weather patterns. The nature of the supratidal subfacies is a direct response to the prevailing climate in the region (Hardie and Shinn, 1986). If the climate is arid, like the modem Persian Gulf carbonate environments, then the supratidal subfacies will carry evaporite and aeolian features (Shinn, 1983). If the climate is rainy, like the modem Andros Island tidal flats, then the supratidal deposits will carry freshwater marsh and lake features (Hardie, 1977; Shinn, 1983).
The stratigraphic record abounds with shallow water carbonate deposits characterized by meter-scale vertical successions of subfacies that are organized into shallowing-upward "cycles", as revealed by analysis of primary sedimentary structures and early diagenetic features (Wilson, 1975; James, 1984; Hardie and Shinn; 1986). Vertical stacks of such shallowing-upward cycles record repeated fluctuations in relative sea level. In some cases these sea level fluctuations appear to be periodic oscillations, driven by Milankovitch astronomical rhythms (e.g. Goldhammer and others, 1987, 1990). Clearly such cyclic shallow water carbonates take on a special significance as storehouses of information about global climatic and eustatic variations in the past.
Overall, an understanding of the origin and significance of primary sedimentary structures and early diagenetic features is vital in our quest to unravel the origin and significance of carbonate deposits in the geologic record. Without such an understanding at the individual sedimentary structure scale we cannot hope to accurately reconstruct the large scale accumulation history of carbonate buildups or to decipher the roles of sea level changes, sedimentation rates, subsidence rates, and tectonics in determining the facies stratigraphy, cyclostratigraphy and sequence stratigraphy of these buildups. In summary, it could be said that unless we get the little things right we may not be able get the big things right.
With this in mind, the purpose of this trip is to examine two or three sections of the Manlius Formation (Lower Devonian) near Hamilton, New York. We are principally concerned on this trip with describing the subfacies that comprise the Manlius Formation in this area. We shall then use the sedimentary features preserved in these rocks to interpret their depositional significance. Defining cycles of subfacies that record relative sea level changes in the Manlius Formation is a controversial matter. One need only compare: (1) Laporte's (1975) original ideas. about migrating tidal flat islands; (2) the shallowing-upwards cycle definitions of Kradyna (1992); and (3) the allocyclic stratigraphy of Anderson and Goodwin (1991). Literally every possible kind of cycle and interpretation of cycle significance have been suggested for this unit. It is not our intention to review this controversy. However, it is our contention that a thorough analysis of the primary and early diagenetic sedimentary structures that are so well preserved in this unit must be the starting point for any paleo-environmental analysis of these rocks including any analysis of their cyclostratigraphic significance. GEOLOGIC SETTING
The Manlius Formation is the lowermost unit of the Helderberg Group, a succession of Lower Devonian carbonates exposed across central and eastern New York. Rickard (1962) interpreted the Manlius Formation as time transgressive from east to west. Figure 1 is a portion of Rickard's (1962) stratigraphic chart of the outcrop belt of the Helderberg Group across central New York from Cherry Valley on the east to Syracuse on the west. Here the Manlius Formation is very nearly flat-lying and is divided into a number of members (Fig. 1).
DESCRIPTION OF MANLIUS SUBFACIES
Figures 2 and 3 are measured stratigraphic logs of the Manlius Formation from two stops of this fieldtrip: (1) Clockville and (2) the Jamesville Quarry (locations given in Figure 4). A third optional stop is the quarry at Munnsville. At these three locations the Manlius Formation can be divided into 6 subfacies defined by their assemblages of primary and diagenetic sedimentary structures: (1) grainstone subfacies; (2) microbial bioherm subfacies; (3) wavy to lenticular thin bedded subfacies; (4) laminite subfacies; (5) disrupted mudstone subfacies; and (6) thin beddite subfacies. These are described below.
A note on the significance of the colors of the rocks is in order. In outcrops in this part of the Appalachians the color of a well weathered surface is a fairly reliable guide to the mineralogy of the rock. Limestone (composed of low magnesium calcite) generally weathers blue or grayish blue. On the other hand, dolomite (CaC O3·MgCO3) commonly weathers a tannish yellow. Dolomite takes on this color upon weathering as most natural dolomites have small amounts of iron substituting for Mg. Upon weathering the iron oxidizes and stains the rock with iron oxide.
Grainstone Subfacies
The grainstone subfacies is composed of intraclastic, bioclastic, and peloidal grainstones and conglomerates. The grainstones are generally well sorted and individual sets vary from coarse to fine sand-sized. Intraclastic conglomerates have rounded clasts up to 20 mm in diameter. In two outcrops of the Manlius Formation we will examine, the main primary sedimentary structure of the grainstones and conglomerates is planar stratification. The sets of planar strata are tens of millimeters thick and are separated by dolomite-rich seams a few millimeters thick. Cross-stratified grainstones are rare in these two outcrops; one probably example is 4.5 m above the base of the Jamesville Quarry section.
Microbial Bioherm Subfacies
The microbial bioherm subfacies includes thrombolites and stromatolites found at the Clockville and Munnsville Quarry sections. The thrombolites of the Manlius Formation are described in Browne and Demicco (1987). Aitken (1967, p. 1164) proposed the term thrombolite: "(from the Greek thrombus, blood clot) ... for cryptalgal structures related to stromatolites, but lacking lamination and characterized by a macroscopic clotted fabric." Other terms that are commonly used to refer to these and similar structures are "bioherm" and "biostrome" (e.g. thrombolitic bioherm or biostrome). The former term refers to discrete mound or coalesced mounds (interpreted to be of organic origin) embedded in rocks of a different lithology whereas a biostrome is a layer consisting of and built mainly by organisms. Manlius Formation thrombolites occur as discrete mounds, as coalesced mounds and as continuous biostromes. Figure 5 is a bedding diagram of a portion of the Clockville section illustrating the three layers that contain thrombolites. The basal layer (0 to 1 m) contains discrete mounds up to 1 m thick and coalesced mounds where laterally adjacent thrombolites have welded upon upward growth. The thrombolites in the bottom layer are surrounded by planar-stratified grainstones. The upper most layer at Clockville (3.8 to 5 m above the base) is a biostrome. Irregularly- shaped pockets of grainstone and intraclastic conglomerate are found within this layer. The middle layer of thrombolites between 2.9 and 3.8 m is an interesting and complicated one. The lowermost 200 mm of this layer is a continuous thrombolite biostrome with stromatolites nucleated on its upper surface. Higher up in the layer are scattered, discrete, delicate thrombolites composed of upward-directed fingers of mudstone. These also are capped with stromatolites. All of the stromatolites in this layer have "gravity defying" mudstone laminae. However, surrounding the gravity defying laminae are wavy laminae of fine peloidal sand that are quite different. These wavy laminae are part of the wavy and lenticular thin bedded subfacies and are more fully described below.
The internal structures of thrombolites of the Manlius Formation at the hand-sample scale are complicated. Structures are visible in sawn slabs and in those outcrops which have been delicately etched by selective weathering. Internally, Manlius Formation thrombolites comprise millimeter- to centimeter-scale mudstone masses ("clots" or "mesoclots") surrounded by skeletal mudstones, skeletal wackestones, skeletal packstones, or rare sparry patches. The mudstone masses typically make up 30 to 50 % of the rock and vary from highly irregular shaped to vertically-oriented columns with circular cross-sections in bedding plane views. Columns can branch upward. There are two types of thrombolites at the Clockville section: (1) those found between 0-1 m, 2.8-3 m, and 3.75-5 m above the base; and those found at 3.5 m above the base.
Mudstone masses in the thrombolites found between 0-1 m, 2.8-3 m, and 3.75-5 m above the base at Clockville are made up of 5 components: (1) millimeter-scale hemispheroids with radial and concentric structure which Browne (1986) interpreted as the problematic fossil Keega; (2) variable amounts of the problematic fossil Renalcis and masses of micrite that superficially resemble this form; (3) stromatolitic mudstone laminae; (4) peloidal laminae with micron-diameter filament molds; (5) rare, sub millimeter-scale brachiopod, ostracod and gastropod fragments. In some cases Browne (1986) reported possible framework-building skeletal red algae encrusting the sides of mudstone clots. Structureless skeletal mudstones, wackestones and packstones that are lighter in color fill the spaces between the mudstone masses. Millimeter-scale burrow-tubes filled with peloids disrupt the fills among thrombolitic mudstone clots and fingers but do not cross-cut them.
The thrombolites in the layer at approximately 3.5 m differ from other Manlius Formation thrombolites insofar as the digitate fingers that make up these thrombolites are dense mudstone and they do not contain microfossils. Also, the fingers of these thrombolites are surrounded by mudstone with no skeletal fragments. Finally, the thrombolite mounds themselves (and the ones immediately below) are capped by stromatolites and surrounded by a unique subfacies: the wavy to lenticular thin bedded subfacies described below.
Wavy to Lenticular Thin Bedded Subfacies
The wavy to lenticular thin bedded subfacies is only found in the outcrops of this field trip surrounding thrombolites and stromatolites 3.5 m above the base of the Clockville section. The rocks comprise dolomite fine-grainstones alternating with dolomite mudstones. Mudcracks are rare. The grainstones have flat bottoms and wavy tops. The wavy tops of the grainstone layers appear to be oblique cuts through wave ripples and, indeed, internally the grainstone layers are sets of wavy fine lamination typical of oblique cuts through wave ripples (see de Raaf and others, 1975). The mudstone layers also are sets of fine wavy laminae. These mudstone layers drape the ripple-marked surfaces of the grainstones, thinning over crests and thickening
The geometry of the limestone layers and sets varies from planar and continuous through discontinuous lenses to notably wavy and nodular forms similar to "nodular", "irregular", "flaser", and "lumpy bedding" described by Wilson (1975), Wilson and Jordan (1983), Matter (1967), and Schwarz (1975), among others. At the lateral boundaries of the nodules, internal graded layers within the limestone patches thin by compaction and pass laterally into dolomitic shaley partings. Other volume reduction features are very common in these rocks, especially in the mudstones and wackestones. Stromatoporoids and corals of various scales are common in the thin beddite subfacies of the Manlius Formation. In many cases, these rigid skeletons are encased in dolomitic shaley seams which bend around the skeleton from both above and below (drag or penetration effects of Pray, 1960). The affected seams thin laterally directly above and below the bioherm and show increasing dips and thicknesses down the sides of the skeleton. Significantly, seams are thickest along the flanks of the skeleton and thin not only over and under the bioherm but laterally away from the bioherm as well. It is important to note that nodules of mudstone show the same drag effects of shaley dolomitic seams around them just as the stromatoporoids and corals do. This, in turn, suggests that the limestone nodules were hard at the time of compaction as well.
COMPARATIVE SEDIMENTOLOGIC INTERPRETATIONS
By far the easiest rocks to interpret are the laminites. The crinkled geometry of many of the laminae; a number of which are clearly composed of detrital fine-sand and silt-sized peloids, suggests that sediment laminae were agglutinated by a sticky microbial mat. The desiccation cracks suggest periodic exposure. Moreover, the prism-cracks imply the periodic rise and fall of a ground-water table (Ginsburg, 1991, pers. comm.), and drying out in the vadose zone. Modem analogs of this subfacies are found beneath high intertidal to supratidal subenvironments of low-energy tidal flats where there is an organic mat dominantly composed of cyanobacteria ("blue-green algae"). Modem examples of laminated sedimentary deposits directly influenced by a surface mat of cyanobacteria have been described from : (1) the supratidal islands of Florida Bay (Ginsburg and others, 1954); (2) the intertidal and supratidal mud flats and coastal marshes of Andros Island by Black (1933), Monty (1967, 1972, 1976), Monty and Hardie (1976), and Hardie and Ginsburg (1977); (3) the intertidal and supratidal mud flats of the Trucial Coast of the Persian Gulf by Kendall and Skipwith (1968) and Kinsman and Park (1976); (4) the intertidal sand and mud flats of Shark Bay in Western Australia (Davies, 1970; Logan and others, 1974) and (5) the siliciclastic mud flats accumulating behind barrier islands of the Delmarva Peninsula, Virginia, by Harrison (1971). Subaerial desiccation of thick fleshy surface mats results in disruption into polygonal cracks (e.g. Kinsman and Park, 1976) the upturned edges of which become preferential sites for growth of the succeeding generation of cyanobacteria to produce oversteepened "stromatolitic" layering (e.g. the type C algal heads of Black, 1933). The anticlinal tepee-like buckles of the laminite 4.3 m above the base of the Jamesville Quarry section have two possible origins. Lateral expansive growths of cyanobacterial mats can produce buckles in soft sediment (see Figure SA and 8B, p. 178, in Shinn, 1983). Alternatively, expansive growth of cements within crusts forming in the high intertidal to supratidal zone can produce anticlinal buckles where crusts overthrust and break.
The laminite subfacies of the Manlius Formation records deposition on a tidal flat. However, it should be noted that "tidal" is used in a rather loose way. The periodic introduction of sediment onto most of the modem examples cited above is by storms. Indeed, for many modern tidal flats, the normal tidal process is to inundate the cyanobacterial mats with clear water. Many modern examples are more properly called wind tidal flats insofar as the prevailing wind direction can have as much, if not more, to do with the flooding of the flats as the tides do.
The disrupted mudstone subfacies also has a quite elegant modern analog: the mudcracked soils developing on modern playas in closed basins and supratidal flats (Smoot, 1983; Smoot and Katz, 1982; and Smoot and Lowenstein, 1991). These modern playa muds are riddled with mudcracks of various sizes and spacings that are open at the surface but at depth are filled with mud, muddy sand, or sand. Mudcracks branch and connect via a complicated network of sheet cracks that surround irregularly-shaped patches of finer mud. Within these modern muds are irregularly shaped fenestrae that are the result of entrapped air bubbles and desiccation. Typically, laminated Pleistocene lake clays grade up through a brecciated zone into a chaotic mud disrupted by complex, superimposed mudcracks. This sequence strongly resembles the smaller cycles that comprise the disrupted mudstone subfacies. It is interesting to speculate as to the time value of each of the small cycles in this subfacies because Holocene/Pleistocene examples may record thousands of years of slow aggradation and intense disruption by desiccation.
The thrombolites of the Manlius Formation are similar to their more common Cambrian and Lower Ordovician counterparts and are similarly interpreted as small, in-place mounds that were hard, rigid bioherms with a biogenic framework when deposited; in other words, they were biological reefs. The clotted mudstone that makes up Manlius Formation thrombolitic fingers is interpreted as calcified cyanobacterial filaments similar to Girvanella. The problematic microfossil Renalcis is generally interpreted as calcified coccoid cyanobacteria or an encrusting foraminiferas. The enigmatic micrite clots that give thrombolites their name have also been interpreted to be the result of calcification of cyanobacterial mats and colonies.
Oddly enough, thrombolites of the Paleozoic resemble in some respects porous carbonate mounds that were deposited in Pleistocene and Holocene pluvial lakes collectively known as tufa. Pleistocene to Modern lacustrine tufas comprise mounds and coalesced mounds that make large encrustations up to 30 m high. Internally, lacustrine tufas may be composed of: (1) rigid centimeter-scale clots and fingers composed of micrite that strongly resemble Renalcis, Girvanella, etc.; (2) stromatolitic laminae and small stromatolites; and (3) dendritic masses and arborescent millimeter- to centimeter-scale "shrubs" interpreted by Chafetz and Folk (1984) to be calcified bacterial colonies. Surrounding these framework elements in lacustrine tufas are a variety of detrital sediments, many of which show evidence of penecontemporaneous cementation.
The wavy to lenticular thin bedded subfacies surrounds thrombolites and stromatolites 3.0-3.75 m above the base of the Clockville section. We are not sure of the origin of this subfacies and critical to any interpretation is whether these rocks are mudcracked. They probably represent alternating layers of wave-ripple cross-stratified fine sands and suspension settle-out of mud, implying an on-off wave regime. Furthermore, these rocks are not bioturbated, they contain stromatolites which are otherwise rare in the Manlius Formation, and associated thrombolites contain no microfossils. These observations suggest that this is the deposit of a sub-environment with waters inimical to organisms. Our best guess is that this subfacies represents some kind of restricted pond or lagoon with elevated salinities developed behind a lateral barrier.
The grainstone subfacies surrounds thrombolites at the base of the Clockville section and is likewise interpreted as a shallow subtidal shelf deposit. The common planar stratification implies that deposition commonly occurred beneath an upper-stage plane bed generated by either unidirectional or oscillatory (wave) currents. The common fining-upwards sets capped by finer-grained dolomites suggests these are storm deposits.
The thin beddite subfacies has long been recognized as subtidal shelf deposits (Laporte 1967; Walker and Laporte 1970). We concur. However, we feel that there are two features of this rock type worthy of note.
First, these rocks have been severely effected by diagenesis. There is ample evidence of differential cementation and differential compaction in the common drag effects of layering around both hard skeletal elements and nodules of limestone. Moreover, the obvious association of the shaley dolomitic partings with compacted sediment opens the door to consideration of pressure-solution dolomitization (Wanless, 1979; and Logan and Seminiuk, 1976). Indeed, most of the preserved layering here might be due to early, layer cake diagenesis argued for by Bathurst (1987). The nature and significance of dolomite and shaley dolomitic partings (which, after all apparently define the main layering style) in these rocks must await formal study of the diagenesis of this formation.
The second point about the thin beddite subfacies of the Manlius Formation is that we see absolutely no compelling reasons to subdivide these rocks. The nature of the diagenetic overprints, the nature of the internal sedimentary structures, and the nature of their preserved fossils suggest that these rocks are rather insensitive indicators of water depth. Moreover, there is no one no parameter in these rocks that is sensitive to water depth. Wave ripple marks preserved on bedding surfaces would be an obvious place to start considering their potential for quantitatively giving water depth (Komar, 1974; Clifton, 1976). However, much of the waviness of bedding surfaces in this subfacies may be the result of diagenesis. As an example of the difficulty in interpreting water depth we would like to draw attention to the grainstone coset 8 m above the base of the Clockville section. At first consideration, it may seem that this would be a good place to "draw a line" separating deposits of different water depth. However, examination of the thin beds above and below this layer will reveal similar, thinner sets of coarse grainstones. In this respect, and in its overall geometry and crude internal organization, this grainstone most likely represents a storm deposit on the shelf similar to those from siliciclastic shelves. We do not think that such "event layers" are necessarily good candidates for major changes in depositional environments.
CONCLUDING REMARKS
We hope that we have shown that the sedimentary and diagenetic features of the Manlius Formation are a storehouse of information that is vital to any attempt to unravel the depositional significance of these rocks. Questions need to be answered before the larger-scale significance of these rocks can be addressed. What was the nature of the original deposits that were diagenetically altered into the thin bedded subfacies? What is the sequence of diagenetic events that effected these deposits? Are there storm deposits preserved in this subfacies or are there significant depositional breaks? What is the nature of the small-scale, desiccating upward cycles preserved in the disrupted mudstone? How much time do they represent? Are they caliche soils like those capping Pleistocene carbonates of the Florida- Bahama Banks Province? Are there tepee structures preserved that imply early cementation?

STOP 1. Clockville Quarry

STOP 2. Jamesville Quarry

STOP 3. (Optional) Munnsville Quarry

A4: SEDIMENTOLOGY OF THE DENLEY LIMESTONE (MIDDLE ORDOVICIAN,TRENTON GROUP) IN CENTRAL NEW YORK
Charlotte J. Mehrtens
Burlington, Vt. 05405
The Denley Limestone of the Trenton Group (Middle Ordovician) in central New York is characterized by nearly 90 meters of alternating beds of limestone and shale. The origin of limestone and shale couplets in general is problematic, however, in the case of the Denley Limestone, the limestones can be shown to be bioclastic turbidites in origin. These bioclastic turbidites are recognized by Bouma divisions within the limestone beds. Interbedded shale horizons represent the in situ sediment. This sedimentologic interpretation has implications for the paleoenvironmental setting of the Denley Limestone.
This field trip will ask you to address the following questions: (1) How can resedimented carbonates be distinguished from in situ sediment? (2) How can tempestites be distinguished from turbidites? (3) Why should one bother with the tempestite/turbidite distinction?
FIELD TRIP ROAD LOG: SEE BRETT AND BAIRD, TillS VOLUME

A5: LATE WISCONSINAN GLACIAL LAKES OF THE WESTERN MOHAWK VALLEY REGION OF CENTRAL NEW YORK
Jack Ridge
Tufts University
Medford, MA 02155
David A. Franzi
S.U.N.Y. Plattsburgh
The glacial history of the western Mohawk Valley region (Fig. 1) is critical to evaluating the contemporaneity of glacial events in the Great Lakes region, the Hudson-Champlain Valley, and New England. Understanding the composition and stratigraphy of glaciolacustrine deposits is particularly important to defining the positions and advances of impounding ice lobes, the pattern of ice recession in the Ontario Basin, Mohawk Valley, and Adirondacks, and the timing of the eastward release of water from the eastern Great Lakes region during Late Wisconsinan time.
Until recently, considerable controversy existed over the character of ice recession and the existence of regional glacial lakes and their levels in the Mohawk Valley. Several early workers recognized the widespread evidence for eastward (Ontario Lobe) and westward (Mohawk Lobe) ice flow in the Mohawk Valley (Dana, 1863; Chamberlin, 1883, 1888; Brigham, 1898, 1908; Cushing, 1905; Miller, 1909). A lack of deposits that clearly define ice-marginal positions in the Mohawk Valley led Cushing (1905), Brigham (1911, 1929), and Fairchild (1912) to conclude that ice in the lowlands receded by stagnation and down-wasting, rather than by back-wasting of an active ice margin. Fairchild's (1912) reconstructions depict lowland ice lobes that surrounded an ice-free Adirondacks during deglaciation. Fairchild inferred that deep glacial lakes, which drained southward across the Appalachian Upland, were impounded between the Mohawk and Ontario Lobes (Fig. 1) during deglaciation. Brigham (1911, 1929) opposed this idea based on a scarcity of lacustrine deposits above an elevation of 200 m. Recent stratigraphic studies (Fullerton, 1971; Krall 1977; Franzi, 1984; Ridge, 1985; Muller and others, 1986; Ridge and others, 1990; 1991) have provided evidence that deep, regional preglacial lakes formed at the margins of active lowland ice lobes at elevations up to 475 m. The lowland lobes formed prior to the deglaciation of most of the central Adirondack highlands. Regional deglaciation occurred primarily by calving at deep water, active ice margins, but was interrupted by several episodes of lowland ice readvance.
The purpose of this excursion will be to examine the evidence and history of glacial lakes in the western Mohawk Valley region. The lithostratigraphic model for the West Canada Creek valley, the application of paleomagnetism, and the genetic interpretation of sediments as related to glacial dynamics will be discussed.

A5: LATE WISCONSINAN GLACIAL LAKES OF THE WESTERN MOHAWK VALLEY REGION OF CENTRAL NEW YORK

Swampy lowland to the west
Swampy lowland to the west is the channel leading south from Cedarville col.

STOP 1. Overview of Cedarville col (1210 ft)
Overview of Cedarville col (1210 ft) which is on the divide between the unadilla River (Susquehanna Basin) and Steele Creek (Mohawk Basin) drainages. Cedarville col served as the outlet for Lake Cedarville, a high level Valley Heads lake in the Mohawk Valley (Figs. 5 and 10-12).

Steele Ck. descends into Ilion Gorge
Steele Ck. descends into Ilion Gorge which exposes much of the late Ordovician through Silurian stratigraphy of the western Mohawk Valley. Red shale exposed in the gorge is the Vernon Shale which is the source of the red color in glacial units of the region. A large inwash delta at the mouth of Steele Ck. in the Mohawk Valley indicates that Ilion Gorge was largely cut during the late Pleistocene existence of Lake Amsterdam.

Town of Kast Bridge.
In the next mile, bluff section 828 (Fig. 17) will be visible across W. Canada Ck. The flat top of the bluff to the east is the surface of the Holland Patent Diamicton and silt and clay of the post-Holland Patent beds (Figs. 2 and 13).

Bluff section 811
Across W. Canada Ck. from campground is bluff section 811 (Fig. 17).

STOP 2. Fishing Rock Rd. bluff, section 324 (Fig. 17).
This section has Precambrian gneiss at road level with two striation directions overlain by thin, discontinuous till in the West Canada Diamicton. The diamicton is overlain by sand and gravel and mass flow diamicton beds of an esker/subaqueous fan complex in the base of the upper Newport Beds. Fan deposition at this location may have been triggered by the lowering of Lake Newport at the close of pre-Valley Heads glaciation (Figs. 2 and 9).

West Canada High School.
The school sits on fluvial terraces graded to Lake Amsterdam or its immediate predecessor in the Mohawk Valley.

Rt.28 crosses over White Creek.

Bluff section 451 (Fig. 17)
Bluff section 451 (Fig. 17) is the embankment to the right.

STOP 3: Newport bluff, section 447 (Fig. 17).
This bluff exposes the top of the pre-Valley Heads section (Middleville Fm.) which is overlain by the Valley Heads section (Poland Fm.). The two units are separated by the Shed Brook Discontinuity at this exposure (Fig. 2).

Workshop site of Linus Yale
The octagonal limestone house at this corner is the workshop site of Linus Yale, inventor of the Yale Lock.

Gage Rd. climbs to the top of a hill
Gage Rd. climbs to the top of a hill composed of the entire glacial section of the W. Canada Valley (Fig. 2).

Cross over White Ck., enter the Factory Brook valley.

STOP 4: Factory Brook bluffs, sections 225-226 (Fig. 17).
The bluff sections across Factory Bk. contain almost the entire pre-Valley Heads section (Fig. 2). The top of till in the West Canada Diamicton at this exposure shows subglacial grooving that records Mohawk Lobe ice flow to the northwest. The top of pre-Valley Heads deposits (upper Newport Beds) are sub-glacially deformed beneath Valley Heads till in the Norway Diamicton, an Ontario Lobe deposit from the Hinckley-St. Johnsville Readvance (Figs. 10 and 12).

STOP 5: Poland clay pit, section 338 (Fig. 17).
This section exposes lacustrine sediments in the lower part of the Valley Heads Poland Fm. Two important transitions occur in this section. A sudden change from lacustrine sand to dark gray silt and clay varves in the pre- and post-Hawthorne beds marks rising water levels during the initial impoundment of Lake Cedarville. A transition higher in the section from dark gray varves, with only gray ice-rafted pellets (post-Hawthorne beds), to pinkish gray varves, with red and gray ice-rafted pellets (pre-Norway beds), represents the transition from Mohawk to Ontario provenance that occurred between the Salisbury and Hinckley-St. Johnsville readvances. The pre-Norway beds are sub-glacially deformed beneath till in the Norway Diamicton.

Breakout channel of Lake Miller
Rt.8 North enters the breakout channel of Lake Miller as it passes by Hurricane Rd.

STOP 6. Lake Miller delta
Lake Miller delta at the maximum position of the Hinckley-St. Johnsville Readvance (Valley Heads, Ontario Lobe, Figs. 10 and 12). Burt Rd. crosses the distal part of the delta which is graded to a water level of 1410 ft that drained across a spillway into Spruce Creek. Map analysis of delta and spillway elevations in the upper West Canada Valley from this stage of Lake Miller indicates that isostatic tilting in the region was about 4-5 ft/mile. When the Ontario Lobe began to recede, Lake Miller drained southward across the delta by way of the breakout channel along Rt. 8 which served as the spillway for a second stage of Lake Miller at about 1390 ft.

Cross Black Creek

Ohio Sand Plain
The next several miles of the trip will cross areas of the Ohio sand plain which represents deposition of deltaic and lake-bottom sand in Lake Miller. Sand in this area sits on clay and silt of the Newport Beds (pre-Valley Heads).

STOP 7: South shore bluffs of the Hinckley Reservoir.
THIS AREA IS PRIVATE PROPERTY!
The bluffs expose the lower through upper Newport Beds, deposited in Lake Newport during the time of the West Canada Readvance which was confined to the lower W. Canada Valley (Figs. 7-9). Readvance activity of the Mohawk Lobe is marked by provenance changes in varves at the Hinckley bluffs. Varves at the base of the section are sandy, have an Adirondack source, and overlie a very sandy and bouldery Adirondack diamicton. The sandy varves give way to clayey dark gray varves of Mohawk Lobe provenance. Mohawk Lobe varves are then overlain by Adirondack varves marking the recession of the Mohawk Lobe and dropping water levels in Lake Newport. The Hinckley bluffs also have spectacular slump and load structures.

Town of Hinckley.
The bluff tops across W. Canada Ck. to the south are ice-contact deltas built along the receding margin of the Ontario Lobe (Hinckley-St. Johnsville Readvance, Figs. 10 and 12). The deltas are graded to the second stage of Lake Miller which drained through the channel seen along Rt.8 near Stop 6.

North of the town of Prospect.
Prospect sits on the surface of a delta built into Lake Prospect (Franzi, 1984) which formed for a short time during the drainage of Lake Cedarville in the Mohawk and W. Canada valleys.

STOP 8. Bluffs on Cincinnati Ck
Bluffs on Cincinnati Ck. expose later Valley Heads deposits in the upper W. Canada Valley. The base of the section is esker/subaqueous sand and gravel overlain by varves with red ice-rafted pellets (post-Norway beds). Till in the Holland Patent Diamicton overlies the post-Norway beds and it is overlain by an ice-contact delta of Lake Gravesville (Figs. 10 and 13). This locality is just inside the eastern limit of the Barneveld-Little Falls Readvance of the Ontario Lobe.

STOP 9: River Rd. sand pit.
This section is representative of exposures in the broad undulating plain between Rome to the west and Ninemile Ck. to the east. It provides evidence for the final readvance (post-Valley Heads) of the Ontario Lobe into the Mohawk Valley (Ninemile Readvance, Figs. 10 and 16). The section has 0.5-2.0 m of red till (Rome till of Muller and others, 1986) overlying about 10-15 m of lacustrine sand that was deposited in Lake Amsterdam. The sand is subtly deformed at the base of the till which does not occur east of Ninemile Ck.

Pass by landfill entrance on right.
Hill top to right is the Whitesboro Terrace.

STOP 10. The pit shows the interior of the Whitesboro Terrace
The pit shows the interior of the Whitesboro Terrace which is an esker-fed, ice-contact feature formed at a recessional position of the Ontario Lobe during the last gasp of Valley Heads glaciation (Figs. 10 and 15). The terrace appears to be an ice-contact delta because it has 5-10 m of fluvial gravel capping lacustrine sand along what resembles a deltaic topset/foreset contact. However, the contact does not represent a horizontal surface and is tilted regionally down to the east-northeast. The gravel was deposited on a fluvially scoured surface that probably represents trimming of the sand (delta or subaqueous fan?) in response to falling lake levels in the Mohawk Valley. The gravel cap represents the first Ontario Lobe, ice-contact deposit graded to a water level less than 500ft in the western Mohawk Valley (Lake Amsterdam). Further east in the western Mohawk Valley Lake Amsterdam is only recorded by inwash deltas.

A6: GEOLOGY OF THE MOHAWK AND BLACK RIVER VALLEYS - A FIELD TRIP FOR EARTH SCIENCE TEACHERS
Barbara J. Tewksbury
Clinton, NY 13323
Robert H. Allers
Vernon-Verona-Sherrill High School
Verona, NY 13478
Rocks exposed in the Mohawk and Black River Valleys consist of a sequence of Late Precambrian metamorphic rocks unconformably overlain by a sedimentary succession ranging from Cambrian through Silurian in age. A veneer of unconsolidated Pleistocene sediments mantles the bedrock. Changes in plate tectonic setting with time are reflected both directly and indirectly in the changing character of the rock record, and Pleistocene deposits in the region provide clues to Late Wisconsinan deglaciation. The purpose of this field trip is 3-fold: 1) to examine the character of the bedrock, 2) to see how changes in plate tectonic setting are mirrored by changes in the rock record, and 3) to study the record of Late Pleistocene glacial and peri-glacial environments of central New York. The introductory text provides background on the bedrock geology, plate tectonic setting, and Pleistocene history of the region.

A6: GEOLOGY OF THE MOHAWK AND BLACK RIVER VALLEYS - A FIELD TRIP FOR EARTH SCIENCE TEACHERS

Kame delta on tree-covered hill to the east

Kame terraces on west side of road
(see description under STOP 1 )

Hamlet of Deansboro

Crevasse fillings on west side of road
(see description under STOP 2).

Eastern Rock Products Quarry
Good outcrops of Devonian Helderberg Group.

STOP 1. VALLEY HEADS MORAINE, ORISKANY FALLS
Looking south from this vantage point, one can see topography very different from that to the north in Oriskany Creek valley. At Oriskany Falls, a flat-floored valley gives way to irregular hills and hummocky topography. These hills and depressions are known as kame and kettle topography and are part of the Valley Heads Moraine. These deposits at Oriskany Falls are part of a large belt of recessional moraines marking a still-stand or readvance of the Wisconsinan glacier in New York State. The Valley Heads Moraine marks the southernmost extent of the ice sheet to be visited on this field trip. The Olean and Binghamton stages are also marked by similar deposits farther to the south, but the Valley Heads Moraine is the most distinctive belt of morainal deposits in central New York.
The hummocky terrain at Oriskany Falls formed by differential melting of sediment-laden ice at the glacier terminus. Ice advance from the north and ablation (primarily due to melting) must have reached equilibrium, and, for a time, the ice front neither advanced nor retreated. Judging from the size of the Valley Heads Moraine, this still-stand may have lasted for as much as 100 years.
The moraine loops across the valley, marking the lobate shape of the glacier. Some of the morainal deposits were created as dirty ice melted and released entrained sediment. This process is similar to the process that forms the piles of sediment one finds along roadsides or driveways when snowbanks melt in the spring. Unsorted, unlayered sediment marks the areas where snowbanks were piled in the winter. By analogy, piles of ablation till mark the terminus of the ice sheet and are composed of generally unsorted and unstratified sediment. Stagnant ice blocks trapped in the sediment later melt out, leaving depressions known as kettles (figure 5).
Many moraines contain considerable quantities of stratified drift in addition to unstratified ablation till. These stratified sediments are deposited in depressions on the moraine surface by running water- primarily meltwater from the wasting ice sheet. Within individual layers, sediments are typically moderately well-sorted, although grain size ranges widely from layer to layer. Many of the sediments are fluvio-glacial, and cut and fill structures and cross-bedding are common. While buried ice blocks remain intact, stratified drift occupies depressions in the morainal surface. Once buried ice blocks melt and produce kettles, the topography inverts, producing hills of stratified drift known as kames. The inversion process commonly disrupts stratification in the kame deposits. This hummocky topography is known as a kame and kettle moraine. Most kame and kettle moraines are also dissected by meltwaters that spread the eroded material down-valley in outwash plains. Were we to drive south of Oriskany Falls to route 20, we would be able to see the broad flat outwash valleys developed south of the Valley Heads Moraine. Scattered kettles occur on the outwash plain, and one of the best sits in the front yard of the Madison School on route 20.
In the valley to the north of Oriskany Falls, one can see crevasse fillings (at road log mile point 6.2). These kames of stratified drift were formed as sediment accumulated in large cracks or crevasses in the ice. When the ice melted, these sediments were left as en echelon ridges parallel to one another but at an angle to the valley walls. In addition, one can also see examples of kame terraces along the valley walls to the north (road log mile point 5.7). These formed along the sides of the stagnant ice, as sediment-rich meltwater and rainwater poured off the ice and hills separating the ice tongues. As with all kame deposits, these are composed of stratified drift. However, many of the kames show disrupted stratification, produced as ice melted and removed support from the sediment, causing slumping and faulting.

Large glacial erratic on the west side of the road.

Good view to the W over Sconondoa Valley and Oneida Lake.
Meltwater channel and delta complex can be seen south of Vernon Center in Sconondoa Valley.

STOP 2. RIVERSIDE MALL
Here, we will see a very different type of Pleistocene deposit than the one we saw at Oriskany Falls. Sediments of the Valley Heads Moraine are ice contact deposits; the sediments at Riverside Mall are pro-glacial lake sediments, deposited in glacial Lake Iroquois or Amsterdam. The slope north of the parking lot is underlain by dark-colored, very fine-grained, finely laminated sediments. At the top of the slope, sediments are conspicuously coarser, composed of fine to medium sands with some pebbly layers.
The fine-grained sediments are varved clays, or rhythmites, composed of layers of gray clay alternating with organic-rich silty layers. Overall fine grain size indicates a low-energy environment, away from lake inlets and deltaic complexes. The layers represent seasonal accumulations, and each couplet (varve) represents one year of sediment accumulation. The silty layers form during rapid sediment influx and probably represent summer accumulation, when the ice is melting and releasing sediment to the lake. The clays accumulate during the winter, when the ice is delivering little sediment to the system and proglacial lakes are iced over. Winter accumulations consist only of very finely-divided material that settles very slowly out of the water column. Such material accumulates year-round but is swamped during the summer by coarser detritus fed into the system. Summer layers here are thinner than the winter layers, probably because of the short duration of the melting season.
Clays are notoriously unstable when wet -- witness the periodic devastation caused by clay-lubricated mudslides in California. With the right amount of water, clays and silts are very susceptible to liquefaction when shaken. Vibration causes particles to lose frictional contact with one another, and the mass becomes temporarily liquified and has no shear strength. Once vibration stops, the mass regains its shear strength. A close look at the mall parking lot will reveal many humps and swales, and even more numerous patches. The parking lot is underlain by varved clays and silts. When moisture content is right. vibration from vehicles induces some liquefaction, and the parking lot surface deforms in response to flow of material beneath it. A good drainage plan would have prevented much of the problem.
As you walk northward up the slope from the parking lot, you will notice a distinct change in sediment from varved clays to fine-grained sands. These sands were deposited in an environment of higher energy than that in which the varved clays were deposited.
Sediments at this stop exhibit a nice vertical facies change, indicating a change in lake depth with time. In a typical lake, the coarsest sediment settles in shallow, high energy water nearest the shore and lake inlets. As coarse sediment settles out, only finer material passes into deeper water, and only clays and organic material accumulate in the deeper portions of the lake. The change upslope at Riverside Mall from varved clays to sands indicates shallowing of water with time, either by progradation of a delta or by general lowering of lake level during ice retreat.
In some of the glacial lakes (especially Lake Iroquois), carbonate-producing animals and plants flourished, and layers of marl occur between the coarse sand zones and the silt zones. Marl is a calcareous sediment; in this area, marls are typically rich in shells of tiny gastropods and pelecypods and remains of a calcareous plant known as chara.

Well-developed Pleistocene ground moraine on west side of road.

Nice field of Pleistocene erratics to west of road.

Well-sorted Pleistocene fluvio-glacial sands to west of road.

The large, elongate hill east of the road is Park Hill
The large, elongate hill east of the road is Park Hill and consists of dissected Pleistocene outwash. Several sand and gravel operations exploit the deposit.

Traversing bottom of glacial Lake Port Leyden.

Glacially-polished bedrock knobs east and west of the road.

Delta tops in distance
The horizon to the east across the Black River Valley has a very uniform elevation. That straight horizon corresponds to a well-developed, flat topographic surface at an elevation of about 1200-1250' that shows up very well on the topographic maps of the Brantingham and Port Leyden quads. These flat surfaces are delta tops, formed as sediment was deposited into glacial Lake Port Leyden during the last part of the Pleistocene. Glacial Lake Port Leyden must have been at least as deep as the tops of the deltas; it was no small lake. A look at the topographic maps will show many closed depressions on the delta tops; these were presumably formed as grounded ice, partially covered with deltaic sediments, melted and caused subsidence. The delta slopes have been somewhat dissected since. Glacially-sculpted Deerlick Road lies in the Black River Valley east of the road; it appears to be a roche moutonee.

Good exposure of glacially-polished bedrock east of the road.

Route 12 crosses Roaring Brook.

Floodplain of the Black River
Which floods with great regularity.

Pleistocene boulder fields on west side of road.

STOP 3: CROGHAN ROADCUT (and that's no baloney!)
The rocks in this spectacular roadcut are part of the suite of metasedimentary and metaigneous rocks that make up the bulk of the Adirondacks. These rocks were deformed and metamorphosed during the Grenville Orogeny (1020-1100 Ma), at depths of about 25km below the surface, temperatures of 700-720°C, and pressures of about 7 kilobars. They are quite thoroughly cooked. They are also deformed, and all lithologies in this outcrop, including the ones of igneous parentage, show compositional layering and/or planar alignments of minerals (foliations) acquired during deformation.
There are 3 major lithologies present in this roadcut 1) a mildly-foliated, coarse-grained pink granitic gneiss consisting of pink K-feldspar, plagioclase, quartz, and variable amounts of hornblende with accessory magnetite, biotite, apatite, and zircon, 2) a foliated, very coarse-grained pink augen ("eye") gneiss, with enormous pink feldspar grains up to 2-6 cm long set in a matrix of plagioclase, hornblende, and quartz, and 3) well-foliated, banded gneisses composed of black, pyroxene-biotite and hornblende-biotite gneisses interlayered with pink to gray granitic and augen gneisses. The dark-colored gneisses are composed of biotite, plagioclase, and hornblende or pyroxene, with accessory apatite, zircon, and magnetite. The light-colored interlayers are similar in composition to the granitic gneisses in the outcrop.
In addition to these 3 major lithologies, this outcrop contains minor amounts of amphibolite, biotite-oligoclase augen gneiss, quartzofeldspathic hornblende gneiss, and biotite-plagioclase schist all interlayered with granitic gneisses and granitic augen gneisses.
The foliation is defined differently in each of the 3 main lithologies. In the granitic gneiss, the foliation is defined both by the parallel alignment of dispersed biotite and by alternating layers of different grain size (but similar composition). In the augen gneiss, the foliation is defined by large, flattened and streamlined K-feldspar grains outlined by ribbons of quartz. The foliation defined by the flattened grains is enhanced by an irregular compositional layering defined by lenses of pink K-feldspar (commonly strung out into layers) alternating with stringers of quartz, plagioclase, and hornblende. In the banded gneiss, foliation is defined primarily by alternating layers of different compositions, one light-colored and rich in quartz and feldspar, the other dark-colored and rich in mafic minerals. Within the dark-colored gneiss, foliation is enhanced by the parallel alignment of biotite. None of the 3 major lithologies has enough mica in it for the foliation to also be a good rock cleavage direction. As a result, all of the major lithologies are blocky and tough.
Although these rocks are metamorphic, the outcrop displays many classic relict igneous features. The granitic gneisses were evidently originally granitic magmas that thoroughly and intimately invaded a country rock of dark-colored gneisses. The dark-colored gneisses, then, might well be xenoliths, remnants of the country rock caught up during intrusion of granitic magmas. The great variety of grain size amongst the granitic gneisses, and the complicated multiple cross-cutting relationships attest to a period of multiple intrusions. Evidence in this outcrop also suggests that deformation was going on as the magmas were being intruded (i.e., that the granitic magmas were syntectonic). Some folds in the dark-colored gneisses are truncated by the granitic gneisses, implying intrusion after folding. On the other hand, some granitic gneisses interlayered with the dark-colored gneisses are folded right along with the dark-colored gneiss. In fact, some of the extremely flattened augen in the augen gneisses are folded. Both suggest folding after granite emplacement. Folding after and folding before granite emplacement implies protracted and syntectonic intrusion. Because all units are foliated, deformation must have outlasted the intrusive episodes.
The other relict igneous features in this outcrop are the augen in the augen gneisses. The augen gneiss may also be referred to as a megacrystic gneiss, in allusion to the enormous size of the deformed feldspar crystals that make up the augen. The metacrysts or augen are very likely relict phenocrysts formed during early slow cooling of a granitic magma with a two-stage cooling history.
As suggested in the previous paragraph, the protolith (pre-metamorphic rock type) for the granitic gneiss was probably a granite. Metamorphism did very little to its original mineral composition, because temperatures during metamorphism were nearly as high as the temperature of a granitic melt at those depths. In other words, the minerals in the granite were perfectly happy under the conditions of metamorphism. Even though the overall mineral content did not change appreciably during metamorphism, individual mineral grains did become unstable and recrystallize in new orientations in response to deformation in the rock. In this manner, the granite acquired a foliation of recrystallized and aligned biotite and became a granitic gneiss. The foliation defined by interlayers of different grain sizes is likely due in part to inheritance of primary textural differences and in part to deformation.
The protolith for the augen gneiss was probably a porphyritic granite. Its metamorphic minerals are not substantially different from those in the protolith, but deformation and recrystallization produced a well-developed foliation in the rock. If you look carefully at the augen gneisses in this outcrop, you will see that there is a range in texture from blocky pink feldspars set in a poorly-foliated matrix to stringers of pink feldspar set in a well-foliated matrix. These differences in texture undoubtedly result from differences in intensity of deformation. As the amount of shearing in a layer increases the feldspar tabs flatten. Strain is highest along the margins of the grains, particularly at the corners; the edges and corners of the feldspars begin to recrystallize into networks of tiny, stable feldspar grains (figure 6). These tiny grains are then no longer part of the larger feldspar tab - they have been, in effect, transferred to the matrix. Plastic flattening of the grain, then, is accompanied by some grain size reduction and a change of grain shape from blocky to eye-shaped. Some of the large feldspar grains are also fractured, if plastic deformation in the grain can't keep up with deformation in the rock. Changes are also happening in the matrix minerals. Platy and prismatic minerals such as biotite and hornblende recrystallize parallel to the flattening plane of the feldspar tabs, creating a foliation wrapping around the developing augen. Coarse quartz grains become flattened, ribbon-shaped grains oriented parallel to the foliation and wrapping around the augen. Many of these deformed quartz grains undergo the same kind of dynamic recrystallization that affects the margins of the feldspars. New, tiny grains of quartz form from the old strained grains. Quartz is very susceptible to the dynamic recrystallization process and undergoes grain size reduction much more readily than feldspars. Therefore, when you look at the augen gneiss, realize that some of the disparity in grain size between augen and matrix was produced during deformation. In fact. many augen gneisses of the world began life as uniformly coarse-grained rocks: not all augen gneisses had porphyritic parents.
Determining the protolith for the dark-colored gneisses is somewhat more problematic, and both igneous and sedimentary protoliths are possible. The dark-colored gneisses are intimately interlayered with light-colored gneisses and augen gneisses to form packages of conspicuously banded gneiss. Questions concerning the origin of the banding cannot be answered unequivocally. The fact that many of the light-colored layers can be traced to larger masses of granitic gneisses suggests that at least some of the banding may be intrusive, the result of intimate interfingering of dark gneiss and granitic magma (a lit-par-lit gneiss). Layers that cannot be traced to a granitic mass may be either light-colored layers in the original country rock, or granitic material derived very locally by partial melting of the dark-colored gneiss and creation of migmatites. Considering that metamorphic temperatures were very close to the minimum melting temperatures of many types of metasediments, the ultimate source of the large volumes of granitic magma in the Croghan area was very likely the metamorphic complex itself. Local partial melting of the dark gneisses may have taken place as well.
After viewing the Precambrian geology, let's jump ahead about a billion years to see what effect the Wisconsinan ice sheet had on this locality. The top of the outcrop is a smoothed and polished surface, produced as glacial ice with entrained sediment sand-papered and rounded the hard Precambrian rock. Some differential erosion can be seen along zones of dark gneiss. The grooves and shallow potholes suggest that the outcrop may not only have been glacially scoured but also eroded by running water. Marginal or subglacial meltwaters, particularly related to a stagnant ice mass, are good candidates.
Proceed eastward over the top of the outcrop to a low exposure of Precambrian bedrock about 30 m away. This outcrop displays distinctive scratches and grooves (glacial striae) trending S10-20°W, parallel to the last ice movement direction in the area. Looking south from this outcrop, you will see a hill with a sand quarry. This hill is part of a series of hills extending the entire length of the Lowville quadrangle. The line of hills trends north-south, with a slight dog-leg near this stop. The deposits that underlie these elongate hills are largely unconsolidated sediments dating from the late Pleistocene. As discussed at stops 1 and 2, Pleistocene deposits in this area include ground moraine (both ablation and lodgement till), morainal ridges (typically composed of till overlain by patchy stratified drift), kame terraces and crevasse fillings (stratified drift), eskers (stratified drift), outwash (fluvial deposits), and pro-glacial lake deposits (beach and deltaic deposits, varved clays, etc.). Each of these deposits has distinctive characteristics, and examination of the deposits in this quarry should allow us at least to rule out some of the possibilities. This deposit was originally described by Buddington (1934) as a moraine. However, close examination shows structures consistent with sediment deposited by running water, rather than directly by melting ice. If these deposits are ice contact sediments, deposition was dominated by fluvioglacial processes.
Sediments in the quarry are conspicuously stratified. Scour and fill structures are common. Cross bedding occurs at many different scales, but many layers exhibit planar laminae. A majority of the deposit consists of sand-sized grains, although there are some layers of very fine grains as well as some layers of pebbly sand. Individual layers are typically moderately well-sorted to well-sorted. The characteristics of sorting and stratification in these sediments indicate deposition from a moving current; direct ice deposition does not produce stratified and sorted sediments. Therefore, these sediments are not tills.
Cut and fill structures, cross-bedding, and some pebble imbrication are consistent with fluvial deposition. At this stop, stratified sediment lies directly on water-scoured Precambrian bedrock; there is no intervening morainal till. It appears, then, that at least this portion of the deposit does not represent a veneer of stratified drift over ridges of morainal debris.
Some of the horizons in the quarry consist of thinly laminated fine sand and silt. Cross-bedding is absent, and individual layers are laterally extensive and easily-traceable. These may represent sediments deposited in closed depressions such as small ponds. Some of these fine-grained layers contain cobbles that may well be dropstones.
The fact that these deposits are part of an elongate but not sinuous ridge system suggests that these deposits are not part of an esker, a pro-glacial lake, or an outwash plain (although dissected outwash is a possibility). A stratified ice contact deposit is the most logical choice - perhaps an ice-marginal deposit or a very large crevasse filling in stagnant ice. The fact that slopes on the west sides of the hills are steeper than those on the east sides suggests that the main ice contact side of the deposit may have been on the west.

Tug Hill Plateau
Spectacular view to the west of the Tug Hill Plateau, underlain by Middle and Upper Ordovician sedimentary rocks.

An even better view of the Tug Hill Plateau.

STOP 4. DADVILLE QUARRY
After repeated searches, neither of us has ever found an exposure of the Precambrian/Paleozoic unconformity (Plate I) in the Black River Valley, although such exposures have been reported in the literature (Miller, 1910). The unconformity is spectacularly exposed in roadcuts near Kingston, Ontario, but that's a bit far away for this field trip. The outcrops at the Dadville Quarry constrain the position of the unconformity better than almost anywhere in the Black River Valley, and we'll have to settle for that.
Precambrian granitic gneisses crop out on the north side of the road in front of the Highway Department Building. Standing on the Precambrian, one can look east and see many knobs of Precambrian rock scattered throughout the Black River Valley and nearly buried by Pleistocene sediments. Directly southeast across the road, Middle Ordovician limestones of the Black River Group are exposed in an active quarry. The trace of the unconformity must lie just below the quarry floor, swinging around the base of the hill and across the road west of where we are standing. From the base of the hill, the unconformity dips very gently (only a few degrees) to the southwest.
Why can't we see the unconformity in the quarry? Surely they must have quarried through to the Precambrian in places, you think. In point of fact, they haven't quarried to the Precambrian, and a look at the stratigraphic column in Plate I will tell us why. The quarry owners are interested in limestones, and the Black River Group has good limestones in all but the Pamelia Formation at the bottom of the Group. As soon as they reached the Pamelia, they stopped quarrying.
A look at the topographic map would show that the position of the unconformity is marked here by a distinct break in topography. As we continue to drive south, you might find it interesting to check the topographic map for other breaks in slope, and examine the countryside and outcrops to see whether those breaks in slope mark the Precambrian/Paleozoic unconformity or not.

Bench in the Paleozoic
The houses on the left are perched on a bench in the Paleozoic that marks the contact between the Black River Group and the Trenton Group, both of Ordovician age. That bench and contact can be traced south on the topo map from stop 4. The next major bench to the west lies at a stratigraphic horizon within the lower portion of the Denley Limestone.

Crossing Roaring Brook.
Precambrian basement rock is exposed in the field to the east of the bridge, and Paleozoic sediments crop out immediately west of the bridge in the stream channel. The unconformity must lie somewhere between the 2 exposures, although the actual contact is not exposed at the surface.

Precambrian gneisses and Paleozoic benches
Rounded knobs of Precambrian gneisses dot the field to the east of the road; Paleozoic sediments begin to the west of the road at the first topographic rise. Town of Glenfield to the east The topo map shows how well the topography reflects the geology. The base of the first sharp slope west of Glenfield lies at the Precambrian/Paleozoic unconformity. The first bench marks the top of the Black River Group. The second major bench marks a horizon within the lower Denley Limestone. The third bench marks the top of the Denley, and the 4th bench marks the top of the Steuben Limestone. The base of the major slope at the Whetstone Gulf Campground marks the contact between the Steuben Limestone and the Utica Shale. The last bench lies at the contact between the Utica Shale and the Lorraine Group (equivalent to the Frankfort Shale).

Pleistocene glacial deposits mask most of the rocks near the unconformity.

Route 12 lies on Precambrian bedrock
An outcrop of the Pamelia Formation (lower Black River Group) lies approximately 50 m west up Snugsboro Road.

Outcrops of the lower Black River Group
Outcrops of the lower Black River Group line the lower part of Turin Road to the west.

Road has crossed the unconformity
Between the last mileage point and this one, the road has crossed the unconformity; outcrops of the Lowville Formation (Black River Group) lie immediately west of the road.

Tracks approximately follow the unconformity.
From here south, the railroad tracks approximately follow the unconformity.

Outcrop of Precambrian granitic gneiss east of road
Glacial deposits blanket much of the Precambrian in this area.

Precambrian diopside-quartz-phlogopite gneiss
Precambrian diopside-quartz-phlogopite gneiss on the east side of the road. The protolith for these metasedimentary units was probably a dirty carbonate, such as a sandy dolostone.

Historic marker for the Black River Canal.
The Canal was completed in 1855 and linked Carthage and Rome. In a 35- mile stretch through the steepest terrain, workers constructed 109 locks. The locks were built with limestones quarried from the Black River Group, as were many of the dove-gray stone buildings in the North Country.

STOP 5. SUGAR RIVER, EAST OF ROUTE 12
THIS IS PRIVATE PROPERTY. You MUST obtain permission from Barrett Paving Company (the quarry owners) if you wish to examine the rocks along the Sugar River. The owners have been very generous in the past in allowing groups to visit the exquisite features on their property. However, repeated unauthorized entry by inconsiderate geologists to properties at many other places around the country has rightfully angered many property owners. As a result, many classic localities are now completely off limits, even to those who properly seek permission. Don't take a chance on spoiling the Sugar River spot for everyone else. Be sure to get permission. Encourage others to do the same.
ALSO - BEWARE THE UNUSUALLY LUSH AND PREDATORY POISON IVY.
These beautiful gray limestones are part of the Watertown Formation at the top of the Black River Group (Plate I) and were deposited as a subtidal sequence on the North American passive continental margin during the Early Middle Ordovician. At several stops on this field trip, we will be examining carbonate sequences. Limestones and dolostones, composed of calcite and dolomite respectively, exhibit a wide range of textures and structures, but all share the common characteristic of being biogenically-derived. Very few post-Precambrian carbonates are pure, non-biogenic chemical precipitates. In addition, one should keep the distinction in mind between detrital clastic rocks such as sandstones and shales, whose fragments are derived from weathering of a distant source, and carbonates, whose fragments are derived very locally by organic precipitation of calcite. Neither animals nor plants precipitate dolomite, and virtually all dolomite in the sedimentary record results from replacement of calcite by its magnesium-rich counterpart, dolomite.
In order to help unravel the environment of deposition of a carbonate rock, it is useful to know in what form the calcite or dolomite occurs in a rock. Calcite can occur in a carbonate rock as skeletal debris, carbonate mud, sparry calcite, intraclasts, and pellets; dolomite can occur as early dolomite or secondary dolomite.
Skeletal debris consists of the remains of organisms, sometimes well-preserved in life position and not transported very far. Skeletal debris commonly consists of broken and disarticulated fossils and may be as fine as silt-sized particles.
When communication by currents or biologic activity reduces fossil fragments to mud-sized particles, the material is called carbonate mud. Lithified carbonate mud is referred to as "micrite"- microcrystalline calcite.
Sparry calcite is coarsely crystalline calcite precipitated-as a secondary mineral in pores and burrows. Some skeletal carbonates have a micritic matrix, others have a sparry matrix, depending upon whether the environment winnowed out very fine carbonate particles at the time of deposition.
Intraclasts are non-skeletal fragments >.2mm in size and associated with erosional intervals. They represent fragments of previously-deposited and partly-consolidated sediment (very locally-derived, of course).
Many pellets are probably intraclasts <.2mm in size, although some may well be fecal pellets.
Early dolomite commonly occurs in thin laminae and forms by migration of magnesium-rich waters upward through the sediments, followed by penecontemporaneous replacement of calcite by dolomite. Early dolomite is almost always found in supratidal settings.
Secondary dolomite forms well after deposition of the sediment and is highly variable, filling vugs, replacing calcite, or cementing clastic rocks.
A given carbonate rock may be composed of any combination of the ingredients listed above. Which components are combined and how they are combined governs the appearance of any individual carbonate rock. The word "limestone" describes anything from a hash of boulder-sized fossil fragments to a featureless, ultrafine-grained micrite. In self-defense, sedimentologists have derived a whole raft of esoteric terms ·to convey more than simple "limestone". The following definitions should help you to wade through most field guides:
calcirudites: carbonate equivalent of conglomeratic grain size
calcarenites: carbonate equivalent of sandstone grain size
calcisiltites: carbonate equivalent of siltstone grain size
calcilutites: carbonate equivalent of mudstone grain size
micrite: limestone formed from a carbonate mud
biomicrite: limestone formed from skeletal debris & carbonate mud
biosparite: limestone formed from skeletal debris & sparry calcite
Grain size is generally indicative of the energy of the environment, although one must bear in mind that large fossils do not by themselves indicate a high energy environment, because the animals lived in the environment and were not transported there.
If exposed to periodic exposure and dessication, carbonates may show mudcracks and local erosion surfaces. If deposited by currents, carbonate sediments may be cross-stratified. If burrowing organisms lived and fed in the carbonate substrate, the sediment may show burrows (horizontal or vertical). Active bioturbation (i.e., churning of the sediment by burrowing organisms) may completely destroy any fine-scale depositional structures such as bedding or lamination.
The Watertown Formation is a very dark gray limestone with fossils and fossil fragments floating in a very finegrained matrix. The matrix is micritic, and "dumpiness" of the micrite has prompted Walker (1973) to suggest that the micrite may have been pelletal. Bioclasts (both unabraded fossils and abraded fossil fragments) generally make up 10-30% of the rock, although percentages range as low as 4% and as high as 53% (Walker, 1973). The more fossiliferous lithologies would be properly called biomicrites. In all cases, bioclasts "float" in a matrix of micrite. Black chert nodules are common throughout the unit.
Stratification is virtually absent in the Watertown Formation, because the carbonate muds were completely churned by burrowing organisms who ate their way through the soft sediment. Much of the pelletal texture in the micrite may have originated as fecal pellets excreted as these organisms reworked the sediment. Networks of horizontal burrows thoroughly mottle this limestone and show up well on weathered horizontal surfaces. Mudcracks are absent, as are intraclasts and erosional intervals. Sparry calcite is confined to burrows.
Fossils in the Watertown Formation are illustrated in figure 7 and include:
rugose (horn) corals (Lambeophyllum)
tabulate corals (Foerstephyllum)
stromatoporoids (Stromarocerium)
echinoderm fragments
straight-shelled nautiloid cephalopods (Actinoceras & Endoceras)
bryozoans (Eridotrypa)
rare brachiopods (Dalmanella & Strophomena)
rare coiled gastropods (Loxoplocus)
horizontal burrows of deposit feeders
How high was the energy of the environment in which the Watertown was deposited? The fact that the rock is micrite-dominated suggests that the environment was a quiet, low-energy one, generally incapable of transporting anything but fine to very fine grains. How, then, do we explain the abundant sand-sized bioclasts (which can be felt by rubbing a hand over a weathered surface - they feel like sand scattered in a nice coat of varnish)? Walker (1973) has suggested that most of the sand-sized bioclasts are porous echinoderm fragments. Porosity would reduce their densities and allow them to "behave" as smaller particles would in a current. Okay, but then how do we explain the very large fossil fragments, like the 3-meter-long nautiloids? Large fossil fragments can easily accumulate in a very fine-grained matrix if the animals lived on the bottom or died in the water column above and sank to the bottom. Currents are not required to move them to their sites of accumulation. One would expect that these large pieces might not be significantly abraded, although they may well be broken if someone had dined on the carcasses before they were buried. Lastly, how do we explain the presence of large chert nodules? It turns out that chert nodules are a secondary phenomenon and are formed in a sediment after deposition. Solutions rich in silica soak through the sediment and replace portions of the rock with silica, creating chert nodules. In a carbonate rock, it's not immediately obvious where the silica should come from. In the Black River Group, silica may have come from leached beds of volcanic ash or from solution of fragments of siliceous sponges. Volcanic ash is a good candidate, because thin volcanic ash layers blown from eruptions in the approaching Taconic Island Arc occur sporadically throughout the upper Black River Group.
What clues have emerged regarding the environment of deposition of the Watertown Formation? Fine grain size of the matrix points to a dominantly low-energy environment. Lack of mudcracks, intraclasts, and erosional intervals suggests that the bottom was always below low tide (a subtidal environment). Lack of deep burrowers supports this, suggesting that organisms did not need to burrow deeply to escape a hostile environment. The fauna consists of animals related to those in the Recent that require normal marine salinities (Walker, 1973) and prefer not to be bothered by daily tides. Modern calcareous algae require water depths of less than 80 m in clear water in order to photosynthesize, and Walker (1973) suggests that carbonate mud might have made the water turbid enough during deposition of the Watertown that 10 m might have been the maximum depth for photosynthesis. If we put this all together, we come up with an offshore shallow marine environment with good circulation and rare turbulence. The area would have normally been below wave base, but rare storms likely stirred up the bottom. The water would also likely have been warm, because central New York State was located about 20° south of the equator during the Ordovician. A pleasant place to live.
The limestones along the Sugar River display spectacular solution features, particularly in the massively-bedded Watertown Formation. One is first struck by the smooth, rounded, doughy-looking outcrops, and then by solution enlargement of joints, producing huge blocks of limestone along the streambed. Farther downstream, a magnificent train of potholes lines the stream channel, many containing pothole stones. Solution is as important as abrasion in creating these potholes. The most spectacular solution features, however, are the swallow holes. During a dry summer or fall, the Sugar River vanishes completely into swallow holes and never reaches the confluence with the Black River. However, during high water, a decrease in volume is difficult to see. Some of the lost water emerges as substantial springs along the face of the quarry. A look at the quarry face will suggest to you that the subsurface flow takes place through solution-enlarged joints, many along bedding surfaces, rather than through gigantic subterranean tunnels. DO NOT WALK TO THE EDGE OF THE QUARRY FACE- MUCH OF IT IS OVERHUNG AND UNSAFE. If you walk a short distance northeast, you will find the outlet for most of the swallowed Sugar River water- the Little Sugar River heads in a spectacular blind valley just easy of the quarry. The blind valley shows up well on the topographic map.
Glacial erratics dot the Black River Valley, and there is a very large granitic gneiss erratic smack in the middle of the Sugar River channel. The Sugar River probably makes headway in moving it about once every 200 years or so. (By the by, why aren't there any glacial striae on the bedrock at the Sugar River??)

STOP 6. LOWER TRENTON GROUP, SUGAR RIVER
The fine-grained, fossiliferous limestones and interlayered shales in this outcrop are part of the lower portion of the Trenton Group (Plate I) and were deposited in shallow Middle Ordovician seas at a time when the Taconic Island Arc Terrane had just begun to collide with the continental margin of North America.
The lower 2/3 of the outcrop belongs to the Napanee Limestone, the upper 1/3 to the Kings Falls Limestone. Both are part of the Trenton Group. Geologists who have studied the Trenton have chosen to divide the sequence into a total of 6 formations, only 2 of which are exposed here, and it is interesting to consider why they have done so and on what basis. Rock sequences are divided into formations within which rock types show some degree of internal homogeneity or sequence that distinguishes them from adjacent sequences. Some genetic connotation is implied, and one generally views the conditions or range of conditions of formation for a particular formation to be different from those in adjacent units. If they weren't, they'd all be part of the same formation. Formations must also be thick enough to be mappable at a reasonable scale. Some formation boundaries are obvious. For instance, there is a conspicuous difference between the Napanee Limestone and the Watertown Formation, which we just visited. Anyone would put them into different formations. However, we did not see the upper Watertown or lower Napanee. If they grade into one another, you might not place the formation boundary at the same place I would, and there's nothing wrong with that. Other formational boundaries are not so obvious. Take the one in this outcrop, for instance. The formation boundary between the Napanee below and the Kings Falls above separates thinly interbedded limestones and shales from thickly interbedded limestones and shales. One's first reaction is that there's not that much difference between the 2 units and that it all ought to be one formation. But, when we examine the details, we find that the limestone in the Napanee is dominantly very fine grained and sparsely fossiliferous, while the limestone in the Kings Falls is coarse and very fossiliferous. The subtle change in thickness of beds also marks a change in the environment of deposition, and it does make sense to place a formation boundary between the two.
The limestones in the Napanee are primarily sparsely fossiliferous micrites composed dominantly of carbonate mud (some pelletal) with infrequent, discontinuous skeletal laminae. There are some highly fossiliferous micrites (biomicrites), with many fossils and fossil fragments set in a carbonate mud matrix, and rare biopelmicrites, a fossil and pellet hash cemented by secondary calcite. The limestones are interlayered with black, sparsely-fossiliferous calcareous shales. In general, the coarser, fossiliferous limestones increase in abundance upward (Cameron et al., 1972). The coarser layers show some ripples and cross-stratification, but none of the layers contains mudcracks. The limestones display some vertical burrows, but they are not thoroughly burrow-mottled, as the Watertown Formation is.
In contrast, limestones in the Kings Falls are primarily shelly limestones and fossil hashes; matrix material is dominantly sparry rather than micritic. These limestones are referred to as biosparites or shelly calcarenites. Layers of thinly bedded calcareous shale alternate with layers of limestone, as they do in the Napanee, but limestone layers are considerably thicker in the Kings Falls than in the Napanee. Limestones in the Kings Falls show abundant high energy features, including cross-stratification, ripples, erosional surfaces, intraclasts, and an absence of micritic material (Titus and Cameron, 1976). These limestones accumulated as a collection of fossil fragments in an environment that winnowed out carbonate mud; spaces between fossil fragments were later filled with secondary, coarsely crystalline (sparry) calcite. A close look at a talus block from one of the Kings Falls layers will show you reflections from calcite cleavage surfaces 1 mm or more across - these are calcite grains of the secondary sparry matrix.
The fauna is brachiopod-dominated - about 1/3 of the species present are brachiopods (Titus, 1977). Fossils in the Napanee Limestone are illustrated in figure 8 and include:
brachiopods (Triplesia, Dalmanella, Sowerbyella, Rafinesquina, Strophomena, Paucicrura, Hesperorthis)
bryozoa (Prasopora, Stictopora, Amplexopora)
crinoid fragments
trilobites (Flexicalymene, Isotelus, Ceraurus)
snails - particularly in the lower Kings Falls (Sinuites, Liospira, Subulites, Hormotoma, Loxoplocus, Phragmolites)
ostracodes
coral - in the lower Kings Falls (Lambeophyllum)
The fauna in these 2 formations is dominated by low filter feeders (such as brachiopods and bryozoa), with some grazers (such as trilobites, gastropods, and ostracodes).
What clues have emerged regarding the environment of deposition of the Napanee and Kings Falls Limestones? The absence of mudcracks and other evidence of dessication in both formations, taken together with the abundant remains of marine organisms (few of whom could have managed a twice-daily low tide), suggest a subtidal environment. The dominance of sparry matrix in the Kings Falls and micritic matrix in the Napanee indicates that the Kings Falls was deposited in a high energy environment that winnowed carbonate mud, while the Napanee was deposited in a quieter environment that enabled carbonate mud to accumulate. However, presence of shaly laminae in the Kings Falls suggests that quiet water prevailed from time to time. The presence of cross-stratification, ripples, and erosional intervals, particularly in the Kings Falls, indicates that the environment was frequently above wave base. This conclusion is supported by the presence of fossil hash (coquina) layers, particularly in the Kings Falls. These layers are composed of disarticulated and broken skeletal materials, transported to the site of deposition by currents. Taken together, the evidence indicates deposition in shallow water, in a high subtidal environment The Napanee was probably deposited in a shallow, shelf-lagoon, while the coarse, sparry Kings Falls was deposited in a wave-swept offshore shoal (Cameron et al., 1972; Titus and Cameron, 1976). Both were deposited in water shallower (or at least more agitated) than that characteristic of the Watertown Formation, which we just visited.
The repetitious interlayering of limestone and shale is an interesting puzzle. D.W. Larson (pers. comm., 1984) suggests that the interlayering is a storm-generated phenomenon, with the following scenario. Clay mixed with some carbonate may well have been the steady-state, everyday, slowly-accumulated sediment. The product would have been a calcareous clay mud deposited in a quiet-water environment incapable of transporting the silt-sized to coarse sand or pebble-sized carbonate grains and fossil fragments characteristic of the limestone layers. During storms, energy in the environment would have increased dramatically, bringing coarser carbonate detritus in from adjacent, higher-energy environments, and redistributing carbonate material previously deposited locally. The energy during storms would have been enough to winnow clays at the sediment/water interface, and carbonates of silt size or greater would have accumulated relatively rapidly. If you look carefully, you might even be able to convince yourself that some of the limestone layers in the Napanee are graded, with coarse fossil fragments decreasing in both abundance and size upward from the base of a layer.
In this scenario, the limestone layers represent relatively rapid, storm-related deposition. The rare, thin skeletal laminae within and at the top of limestone layers presumable contain fossils in or near life position and represent a community of organisms developed on the bottom after a storm. Storm-sequence deposition is illustrated in figure 8.
As one goes east in the Trenton Group, sediments record features of deeper water deposition. Here, too, limestones alternate with shales, but the limestones are very different in character. They show features that suggest deposition by turbidity currents in quite deep water. Earthquakes may well have shaken carbonate sediments lying on the shallow shelf to the west, mobilizing them into a great slurry that slid eastward just above the bottom. As the turbidity current slowed, layers of lime sands and muds settled out of the water, draped over the clay muds normally deposited in the environment.
Studies of features such as this tell us that the Trenton Group was deposited in sedimentary environments that ranged from low-energy lagoons to wave scoured barrier shoals, shallow and deep shelves, and a slope connecting the shelf to the west with a basin to the east. One shoreline appears to have lain well to the west of New York State. A shallow shelf extended as far east as the Black River Valley. East of there, water depths varied a surprising amount. Deep water changed to shallow water and back to deep water again several times between Utica and Albany. We think that indicates the presence of a number of fault blocks - horsts and graben - in the transition zone from the western shelf to the eastern basin (Cisne et al., 1982; Kidd, 1991). The eastern shoreline of the basin lay approximately at the eastern border of New York State at the beginning of Trenton time.

STOP 7. WHETSTONE GULF
Throughout the region, the limestones and interlayered shales of the Trenton Group that we saw at Stops 5 and 6 are overlain by hundreds of meters of black Utica Shale (Plate 1). Over the past few thousand years, Whetstone Creek has carved a steep walled gorge into the very fine-grained, soft black shales and siltstones of the Utica Shale and overlying Whetstone Gulf siltstones and shales. The sediments are much finer grained than any others we will see today and were deposited in an environment little stirred by significant currents. The black color derives from abundant unoxidized organic matter, suggesting that the sediments were deposited in a putrid, anoxic environment incapable of oxidizing dead material as it settled quietly to the bottom of the sea. The Utica Shale in central New York State is considerably thicker (over 10X thicker!) than the earlier sediments we have examined, indicating that significant subsidence must have taken place in order to make room for such a thick accumulation of sediment. The muds accumulated in a basin estimated to have been as much as 500 meters deep, produced as the edge of the Laurentian continent foundered as it collided with the Taconic Island Arc.
The change in fossil assemblages is as striking as the change in rock types. The brachiopods, corals, bryozoans and trilobites that are so common in the Trenton Group and characteristic of well-aerated, warm, shallow waters are missing from the overlying shales. Instead, we find scattered remains of graptolites and trilobites preserved in a rock full of unoxidized organic material. Poor circulation in the deep basin produced an oxygen- and food-deficient environment that was highly charged with iron and poisoned by hydrogen sulfide. The water depths were so foul that no organisms lived there. All of the fossils are of organisms that were swimmers or floaters. Their remains evidently settled to the poisonous bottom when they died, and nothing was there to eat them.
Limestones of the Upper Trenton Group in the western part of the region were being deposited at the same time as the black shales in the Champlain Valley and central Mohawk Valley. If we were to look at a number of sections, we would see that the black shale environment gradually spread westward, until all of the Trenton limestones were blanketed by black muds derived by erosion of a high sediment source in the east
As the Ordovician drew to a close, the sediments changed yet again. The Utica Shale and Whetstone Gulf shales and siltstones are overlain by Pulaski and Oswego Formations (Plate I). It is these more resistant units that hold up the Tug Hill Plateau above Whetstone Gulf. There are many indications that water became progressively shallower in the Late Ordovician basin. Younger sediments are coarser in grain size, reflecting higher energy environments. The graptolite and trilobite-bearing Whetstone Gulf Formation is overlain by the Pulaski Sandstone, with abundant shallow-water marine clams and brachiopods. These are in turn overlain by the poorly-fossiliferous coarse beach sands of the Oswego Sandstone. The last units deposited during the Ordovician are not even marine - the basin had been completely filled in. The distinctive red shales siltstones, and sandstones of the Queenston Shale, remnants of which cap the Tug Hill Plateau, show all the features of an enormous deltaic deposit that spread westward across the State.
While walking along the stream channel, notice that the shale and siltstone layers are strongly jointed. Also keep a sharp eye open for fossils in the talus and along the stream bed. Many cephalopods, brachiopods, trilobites, and graptolites can be found. Some of the cephalopods have been replaced by pyrite and look like tiny rolls of gold coins.

Good view of Pleistocene delta tops
Good view of Pleistocene delta tops to the northeast and southeast across the Black River Valley. If you look carefully, you can see sand and gravel quarries in the deltaic deposits. Notice how well these delta tops show up on the topo map.

Valley floor near head of Boonville Gorge.

Sand quarry in Pleistocene meltwater deposits.

Channel narrows into Gorge
Channel narrows into Gorge, where Pleistocene meltwaters were channeled into Lansing Kill. This was the outlet for glacial Lake Port Leyden, and the topographic feature is known as a meltwater channel. Boonville Gorge was cut by meltwaters relatively quickly during the Pleistocene and has been little modified since. The topo map on the next page shows the abandoned channel north of Lansing Kill and the knickpoint where the channel drops into Boonville Gorge.

View southward down steep-walled meltwater channel
Lansing Kill is now a small stream in a large, steep-sided valley.

Outcrop of Middle Ordovician Utica Shale
Outcrop of Middle Ordovician Utica Shale (the uppermost formation in the Trenton Group); the Pleistocene meltwater channel in Boonville Gorge was easily incised into the soft shales of the Utica.

Entrance to Pixley Falls State Park.

More Utica Shale.

Undercutting along meanders
For about 1 km, undercutting along meanders in Lansing Kill is well-developed.

Valley widens; erratic on floor to west of road.

Good view of Delta Lake.

Traversing floor of glacial Lake Iroquois
(before it dropped to the 450' elevation level).

Traversing glacial Lake Iroquois floor at Fort Stanwix.

Cross Barge Canal.

Upward from the floor of glacial Lake Iroquois
The road passes upward from the floor of glacial Lake Iroquois (at 450' level).

Kames or dissected esker in fields to east of road

Kame or esker remnant at Christmas Knob
Kame or esker remnant at Christmas Knob to north of the road. This feature shows up best during the winter when the leaves are off the trees.

Crossing filled Chenango Canal.

STOP 8. CLINTON IRON ORES
The sediments of the Clinton Group (Plate I) are a sequence of extremely varied clastic rocks deposited in nearshore marine environments during the Middle Silurian. Sources for the detritus lay to the east in the eroding highlands of the accreted Taconic Island Arc Terrane. At stop 7, we will have a look at spoil piles dumped during extraction of the Westmoreland Hematite, one of the 2 iron ore horizons in the Clinton Group.
The samples in the spoil piles are dominated by brownish-red calcareous oolitic hematite ore from the Westmoreland Hematite. The ooliths (pron. oh-oh-liths) are approximately 1 mm in diameter and range in shape from spheroids to oblate spheroids. The ooliths are composed of concentric layers of hematite and chamosite (an iron-silicate mineral) deposited around a nucleus, commonly a well-rounded quartz grain (Dale, 1953; Muskatt, 1972). Sliced in half, the ooliths resemble an old-fashioned fireball candy. Ooliths form when minerals precipitate chemically from seawater around a sand grain or fossil fragment nucleus. As currents roll the ooliths around on the bottom, they acquire layer upon layer of chemical precipitate, in snowball fashion. Calcite ooliths are currently forming on wave-agitated portions of the Bahama banks. In the Westmoreland Hematite, ooliths accumulated hematite instead of calcite. The ooliths are accompanied by rare fossil fragments and are set in a matrix of hematite, sparry calcite, and dolomite (Muskatt, 1972). In some layers, hydration has converted hematite to limonite or goethite, giving the layers an orange, rather than red-brown, color.
In addition to oolitic hematite, specimens in the spoil pile contain layers of gray-green siltstone (no ooliths), fossiliferous red shale (with some ooliths), fossiliferous and burrowed green shale, and sparsely oolitic layers with an abundance of rounded intraclasts and quartz fragments up to 1 cm across. Layers are lens-shaped and somewhat discontinuous. Some specimens show well-developed trough cross-stratification, and many of the oolitic hematites show hints of cross-stratification. Megaripples with a wavelength of about .5 m occur along the path east of the spoil pile.
Fossils include brachiopods, trilobites, cephalopods, ostracodes, crinoids, conularids, and traces of many burrowing organisms. Fossils from the Clinton Group are illustrated in figure 9.
What clues emerge concerning the environment of deposition of these units? Presence of cross-stratification, megaripples, coarse detrital particles, intraclasts, erosional intervals, and ooliths all point to a well-agitated environment for the rocks in which these features occur. Finer-grained lithologies demand a quieter environment, and, predictably, these are the lithologies with most of the animal remains and trace fossils. An area above wave base and perhaps occasionally above low tide level is consistent with both sediment types and fauna. Tidal flats, channels, and lagoons inter-fingering with one another seem to be a reasonable scenario for these rocks.
The hematite in these rocks is primary - it accumulated in the sediment right along with the clastic material. The most curious aspect of this, however, is the fact that the iron must have been in solution in the seawater in order for hematite to have precipitated and accumulated as ooliths. This may not seem like much of a problem; after all, seawater is a real soup of dissolved material. The problem is that, under oxidizing marine conditions, iron is extremely insoluble. (Salt water may rust your car, but, once it's rusted, sea water won't dissolve iron oxides off the rusty spots on your car.) Modern marine waters and most river waters contain very little dissolved iron, and there is no evidence to suggest that Middle Silurian seas were very must different overall.
So, what can make iron soluble? Iron dissolves in very acidic waters and very reducing waters; neutralize or oxidize such water, and the iron will precipitate out. Many workers have suggested that sedimentary iron ores such as the hematitic ores of the Westmoreland formed where hot or cold submarine springs debouched acidic and/or reducing water laden with dissolved iron. Upon mixing with normal marine water, iron oxides and silicates precipitated as ooliths or replaced calcite in fossil material (as in the Kirkland Hematite or "red flux") (Stanton, 1972).
Sedimentary ironstones like the Westmoreland and Kirkland ores are referred to all over the world as "Clinton-type ores", names for the Clinton Group and Clinton, New York. Clinton-type ores have been important sources of iron in the past, supporting such famous steel towns as Birmingham, Alabama. Ores in the Clinton, New York area were exploited as early as 1797, and active mining of ore for pig iron continued until the end of World War I (Dale, 1953). As the huge easily-extractable ores of the Lake Superior Iron Ranges were developed during World War I, mine owners found it less and less profitable to extract ore from the 1-2 m-thick hematite layers in Clinton. After World War I, iron ore was extracted for paint and brick pigment only. The operations at Stop 7 were run by the Clinton Metallic Paint Company, and workings were entirely underground. Operations began on Brimfield Street in 1928 and shut down in 1963. The map in figure 9 shows the areas of Clinton undermined by iron ore extraction. Many claim that these underground workings have adversely affected groundwater flow in this area.

Bridge over Dawes Creek.
Herkimer Sandstone (Clinton Group) crops out east of the bridge. Megaripples of two different orientations grace the bedding surfaces along the creek.

STOP 9. EASTERN ROCK PRODUCTS QUARRY, ORISKANY FALLS
At this stop, we will be interested primarily in glacial features exposed at the rim of the quarry. However, we will have a look at the bedrock if time permits.
Portions of 5 Devonian formations are exposed in the quarry. The lower 35 m of gray limestones belong to the Helderberg Group, including 12-15 m of the Manlius Formation, 15 m of the Coeymans Formation, and 2 m of the Kalkberg Formation. 3 m of white Oriskany Sandstone forms the prominent band high on the quarry face above the gray Helderberg. 20 m of gray Onondaga Limestones at the top of the quarry face is overlain by glacial tills of variable thickness. All of the bedrock units were deposited in shallow epicontinental seas during the Early Devonian, after substantial erosion of the accreted Taconic Island Arc Terrane, and prior to accretion of the Avalon Terrane. In a trip eastward from the ocean here at Oriskany Falls during the Early Devonian, one would have encountered a low, broad landmass in what is now New England, more ocean (this time a real ocean basin with oceanic crust), and, finally, the small continent of Avalon.
The Helderberg limestones are a varied lot. Differences in lithology reflect differences in environment of deposition. Carbonate mud matrix in some reflects relatively low energy environments, while sparry matrix in others suggests high energy. Mudcracks show dessication in some, but not all units. Some of the limestones are cross-stratified and were deposited above wave base; others show evidence for being affected by waves only during storms.
The Manlius shows features consistent with environments oscillating between supratidal, intertidal, and shallow subtidal lagoon environments. Walker and Laporte (1970) have suggested that good analogies may be drawn between these limestones and their environments of deposition and those in the early Middle Ordovician Black River Group. The organisms in the communities are, of course, different species, but they occupy similar niches in strikingly similar rocks.
Water deepened episodically but progressively during deposition of the Helderberg. The Coeymans Formation was deposited on a discontinuous barrier shoal in environments that ranged from high to low energy, and the Kalkberg was deposited in a shallow, open marine environment dominantly below wave base (Laporte, 1969; Walker and Laporte, 1970).
The Oriskany Sandstone lies disconformably on the Helderberg Limestone and represents a shoreline sand sequence deposited at the base of the last transgressive sequence in the Early Devonian. These sandstones are coarse-grained and contain remains of enormous brachiopods. Evidently, the energy in the environment was either too high to preserve more delicate fossils, or else was too high to allow less robust organisms to live happily. In southwest New York State, the Oriskany Sandstone is hundreds of meters below the surface and serves as a good reservoir rock for petroleum.
The lower Onondaga Limestone is chertier and coarser-grained than much of the Helderberg Group, but individual pieces on the quarry floor are difficult to distinguish from the gray limestones of the Helderberg. Environments during deposition of the Onondaga were primarily those on wave-affected, shallowly-submerged lagoonal shelves (Lindemann, 1979). Reefs are common and are known to contain natural gas. The Onondaga has been used extensively for building stone, and, obviously, is quarried for aggregate.
At the top of the Devonian sediments in this quarry, we find a very distinctive erosion surface that shows conspicuous evidence of glaciation. If you examine the limestone carefully, you will be able to find examples of striae, crescentic gouges, and chatter marks. The pebbles, cobbles, and boulders that were stuck in the underside of the ice or pressed between ice and rock acted like sandpaper, forming the scratches, grooves, and gouges. Friction between the pebbles and the bedrock caused the pebbles to jump like chalk on a blackboard, forming chatter marks. Direction of striae indicate that this area was overridden both by south-flowing ice from the Laurentide ice sheet and by southeastward-flowing ice from the Ontario lobe.
Unsorted, unstratified glacial till overlies the Devonian rocks and makes up the overburden in this quarry. The till is removed and used by local municipalities as fill. In the unstratified till, you can see the direct contact of lodgement till (ground moraine) with the underlying bedrock. In some of the overburden, areas of stratification occur, where meltwater poured off the ridge to the northeast onto or along the ice sheet that filled the valley.

A7: SEDIMENTATION-EROSION PATTERNS ALONG THE SOUTHEASTERN SHORELINE OF LAKE ONTARIO
Paul R. Pinet
Charles E. McClennen
Hamilton, N.Y. 13346
Bruce C. Frederick
RSMAS, University of Miami
Miami, FL 33149
The southeastern shoreline of Lake Ontario (Fig. 1) is dynamic and evolving rapidly in response to wave conditions, rainfall patterns, groundwater seepage, and short- and long-term variations in lake levels. We have been studying these changes in a systematic way for three years, trying to document the nature of these processes as they interact to produce depositional-erosional effects. The field trip is designed to acquaint you with the results of our work and to show those of you who are in academia the potential this area has for field instruction about glacial and coastal deposits and processes. Furthermore, we hope that some of you may opt to direct your research efforts to some of the many unsolved problems that we will be discussing during the trip.

STOP 1. McIntyre's Bluff
Here we will walk about one kilometer of the shoreline, examining in detail the gullies that are carved into Mclntyres Bluff, the cobble beach fronting the bluff, and a baymouth barrier in front of Juniper Pond.

STOP 2. Little Sodus Bay
Here we will study the impact of shoreline-stabilization projects on erosional-depositional patterns of the adjoining shorelines.

B1: QUANTITATIVE PALEOECOLOGY OF HAMILTON GROUP LOCALITIES IN CENTRAL NEW YORK
Willis B. Newman, James C. Brower, and Cathryn R. Newton
Syracuse University,
The Middle Devonian Hamilton Group has in recent years attracted much interest, including studies published in two volumes edited by Brett (1986) and Landing and Brett (1991). Transgressive and regressive cycles are a prominent feature of the marine sediments (e.g., Brett and Baird, 1985; Brett, Baird and Miller, 1986). The thin cycles in western New York consist of shale, calcareous shale, and limestone and are roughly symmetrical (Miller, 1986; Savarese, Gray and Brett, 1986). Approaching the source area in eastern New York, the cycles become thicker and are dominated by a regressive phase of mostly fine and coarse clastics.
This paper reviews the paleoecology of six typical regressive cycles in central New York based on quantitative multivariate techniques. The work is preliminary and more detailed studies are in preparation. Although Hamilton communities and paleoecology have been the subject of a legion of papers, most of these are qualitative. Examples can be found in the Hamilton volumes mentioned above. Papers emphasizing quantitative methods in the study of Hamilton communities include Brower (1987), Brower and Kile (1988), Brower, Thomson and Kile (1988), and Brower and Nye (1991). Other works using quantitative techniques, mostly cluster analysis, are Miller (1986), Savarese, Gray and Brett (1986) and McCollum (1991). Our analytical strategy operates in a series of steps. In the first stage, communities and gradients are characterized by means of various clustering and ordination algorithms. Both types of techniques are necessary because they are subject to different forms of distortion and they show different structures in the data set. The communities and gradients are tested for statistical significance through a variety of approaches. Both communities and gradients are then analyzed in terms of parameters such as diversity, equitability, and trophic structure. Finally, the causal factors that generated the sequence of communities and gradients are determined.
SUMMARY AND CONCLUSIONS
During this study, six typical cycles of upwardly coarsening clastic sediments have been examined in the Hamilton Group of central New York. Sedimentary sequences were selected from the Marcellus, Skaneateles, and Ludlowville Formations which represent the lower and upper parts of the group. Closely-spaced and large samples, mostly composed of 300 or 1000 specimens, were taken in order to characterize faunal diversity, proportions and ecological structure. The following conclusions are drawn:
1. Samples of 300 specimens are large enough to characterize the most diverse Hamilton communities in this area.
2. The main pattern in all cycles consists of decreasing depth and correlated differences as evidenced by change in sediment grain size, sedimentary structures, amount of organic matter, and faunal composition.
3. The multivariate techniques of cluster analysis and correspondence analysis are successful in the identification of faunal communities or assemblages. They also point to relations between and within communities. The ordination method of correspondence analysis and the clustering algorithms produce complimentary data, and both types of techniques should be employed in concert. Once the analyses are complete, it will be possible to specify average composition and variances for the various communities.
4. Statistical significance tests at the 0.05 probability level have been performed on all pairs of related communities as ascertained from the correspondence analysis plots and the known vertical sequences of communities. As expected, the multivariate means of all communities are statistically different, and all communities differ in average composition. Significance tests on clusters were also employed on the data to test the amounts of overlap in the populations from which the samples were derived. In two locations, Route 20 and Cascade, most or all of the communities comprise samples from rectangular distributions that do not overlap along the observed faunal gradients. These communities seem to have been tightly structured. At the other outcrops, Swamp Road, Cheese Factory Gulf, and Road #4, the pairs of communities come from populations that are characterized by overlapping rectangular distributions. In fact, the parent populations may exhibit as much as 50 percent of overlap (calculated for Gaussian or normal distributions) although lower percentages are more typical. Widely overlapping communities are deemed to be weakly structured and, perhaps, poorly integrated. The significance tests are still being explored.
5. The scores for the samples along the first correspondence axis extract the main pattern of change and relations between the communities for each outcrop and cycle treated. As mentioned previously, the cycles were probably produced by decreasing depth or shoaling, so these scores yield a generalized measure of relative depth. The exact relation between the first correspondence axis and depth cannot be specified at present, and the relationship could be rank order, linear or nonlinear.

B1: QUANTITATIVE PALEOECOLOGY OF HAMILTON GROUP LOCALITIES IN CENTRAL NEW YORK

STOP 1. ROADCUT ON SWAMP ROAD
This outcrop exposes about 20 m of the upper part of the Pecksport Member of the Marcellus Formation (Grasso, Brett, and Baird, 1985). The dark grey shales at the base grade into fine grey to brown coarse siltstones at the top (Fig. 1). Moving upwards, there is a gradual increase in species richness, adult size of the different species, proportion of epifaunal taxa, and a decrease in the abundance of deeper water taxa like Leiorhynchus and Pterochaenia.
The exceptional preservation of calcite and aragonite shells at this locality has been the focus of many studies, for example Bailey (1983) on bivalves, Rollins, Eldredge and Spiller (1971) on gastropods and monoplacophorans, Cameron (1967) on a uniquely preserved annelid worm, and Carter and Tevesz ( 1978) on the shell microstructure of various groups.
On initial qualitative examination, we recognized a Leiorhynchus-nuculid dominated community at the base, grading into a Mucrospirifer dominated assemblage in the middle which was capped by a large clam fauna at the top. Selleck and Linsley (1989) reported that "the fauna is dominated by the brachiopods Spinocyrtia in the upper sandier facies, and Mucrospirifer in the middle siltier layers, along with the bivalves Ptychopteria flabellum, Gosseletia triquetra and a variety of nuculids, gastropods including Bembexia sulcomarginata and Palaeozygopleura harniltoniae plus a variety of orthoconic cephalopods", which is also a fair qualitative statement. The preservation is deceiving. Many of the taxa possess well preserved intact or nearly intact shells composed of black calcite; these weather out and attract much attention as one searches for fossils.
More detailed sampling and quantitative analysis produces different results. The study examined 37 samples, spaced at 0.5 m intervals, consisting of 300 specimens each for a total of 11,100 individual fossils and found a very different picture. Mucrospirifer mucronatus ranges from 0 to 30 percent in any sample and does not dominate a single sample. Gosseletia triquetra yielded only 26 specimens and comprised less than 2 percent of any sample in which it was present. Spinocyrtia granulosa ranged from 0 to 4 percent of the samples. Leiorhynchus multicostum does dominate many of the lower samples found in dark shales, but Devonochonetes scitulus and Ambocoelia umbonata are more common in the higher samples.

STOP 2. Rockslide And Gully In Cheese Factory Gulf
The dark grey and silty shales at this outcrop are assigned to the upper part of the Cardiff Member of the Marcellus Formation (Fig. 5). In general, it represents a more distal equivalent to the upwardly-coarsening sequence seen at Swamp Road. The most interesting aspect about this sequence is that it records the establishment of a stable benthic fauna in an area previously dominated by sparse pelagic taxa such as orthocones and Pterochaenia fragilis. As noted by Brower and Nye (1991), some individuals of Pterocbaenia were probably epiplanktonic whereas others were most likely byssally attached to the substrate.
This part of the section is not generally well exposed because the soft shales weather rapidly and are quickly overgrown. The two exposures here allow comparison of weathered and fresh outcrops. The slide section dates from the early 1970's whereas the ravine developed during the summer of 1990.
The study was conducted on 35 samples taken from the ravine at 0.5 meter intervals (Fig. 5). Approximately 10,500 fossils were counted. Five depauperate samples at the base of the ravine were omitted from the analysis because it was not possible to count 300 specimens.

STOP 3. Roadcut On Route 20 Near Pompey Center
The Route 20 roadcut exposes the Delphi Station Member of the Skaneateles Formation except for the basal and topmost beds. Brower, Thomson and Kile (1988) published a detailed description of this outcrop. Seventy samples were obtained from the section which ranges from shale at the base to fine siltstone and sandstone at the top (Figure 9). The cluster (Figs. 10 a & b) and correspondence (Fig. 11) analyses reveal three communities, Nuculoidea, Schuchenella, and Actinopteria, listed in ascending stratigraphic order. The Nuculoidea community can be divided into three sub-communities. Significance tests on the clusters suggest that they are relatively tightly structured. All assemblages found in adjacent beds represent samples that were drawn from disjunct rectangular distributions at the 0.05 or 0.01 risk levels.
All three communities have equitabilities that are 0.78 or higher and are interpreted as biologically accommodated rather than opportunistic. For example, Brower and Nye (1991) report equitabilities ranging from 0.19 to 0.49 for three Hamilton benthic communities that formed under stressed conditions. Proceeding from the Nuculoidea to Schuchertella to the Actinopteria community, the grain size becomes coarser, ranging from mainly shale to mostly siltstone and sandstone, whereas the organic content decreases from 3.01 to 2.11 percent The number of common taxa per sample rises from about 16 to 23. The lithology and sedimentary structures demonstrate that the Nuculoidea community occupied the deeper and more offshore areas whereas the Actinopteria assemblage lived in the most shallow regions closer to the shoreline.

STOP 4. Private Quarry On Road Number 4 East
About 12.5 m of the lowermost part of the Otisco Member of the Ludlowville Formation is present at this stop (Fig. 13). The lithologies range from shale to fine-grained sandstone and the organic matter content varies from 3.0 percent in some of the shales to 1.2 percent in the uppermost sandstone. Examination of the lithology indicates that three upwardly-coarsening cycles can be seen; the tops of these cycles are at roughly 4 m, 7 m and 12.5 m. Each cycle begins with shale; the two lower cycles are capped by a siltstone that contains abundant Zoophycos caudagalli trace fossils, whereas the upper one ends in sandstone containing a large brachiopod and bivalve fauna.
Three faunal associations were initially apparent in qualitative field studies: 1) A Devonochonetes association characterized by infaunal, deposit-feeding bivalves, gastropods, and abundant Devonochonetes scitulus. 2) A Mucrospirifer association containing a higher diversity fauna of semi-infaunal and epifaunal brachiopods and bivalves. 3) A Protoleptostrophia association dominated by large reclining brachiopods and bivalves. However, this is rather misleading. As in the case of the Swamp Road, the multivariate analyses based on clustering and correspondence analysis reveals a slightly different paleoecological structure.
Large samples were taken -- each sample consists of 1000 individuals in order to study the effects of sample size on faunal diversity and proportions. These results suggest that a sample size of 300 individuals is adequate to characterize these parameters for most diverse Hamilton Group communities. The 54 samples are distributed throughout the stratigraphic section (Fig. 13).

STOP 5. Roadcut On Route 38 At Cascade
Two asymmetrical cycles which coarsen upwards were sampled at this outcrop; an upper one in the Ivy Point Member of the Ludlowville Formation (Fig. 17a) and a lower one in the Otisco Member (Fig. 17b). Brett, Baird and Miller (1986) published a complete stratigraphic section for this roadcut. The two cycles were selected because large areas were available for sampling which contain representative samples of the overall fauna A variety of lithologies are present which vary from dark grey shale with fine laminations and comparatively high amounts of organic matter to fine grey siltstones where organics are relatively sparse. Three hundred fossils were counted in each sample. Inasmuch as only 24 and 16 samples were collected from the lower and upper cycles, respectively, they were amalgamated to give a larger data set with 40 samples. In contrast to the other outcrops examined, two sources of variation reside in the data, namely changes within the cycles as well as contrasts between them.

B2: THE LITTLE FALLS DOLOSTONE (LATE CAMBRIAN) : STRATIGRAPHY AND MINERALOGY
Herman S. Muskatt
Victor P. Tollerton, Jr.
Utica College Of Syracuse University
Utica, New York 13502
The Late Cambrian Little Falls Dolostone is well known for the occurrence of exceptionally clear, doubly terminated quartz crystals, known as "diamonds", and for the irregular hemispherical masses of algal stromatolites, known as "cryptozoons". The areal relations of the Little Falls Dolostone in the field trip area is shown in Figure 1.

B2: THE LITTLE FALLS DOLOSTONE (LATE CAMBRIAN) : STRATIGRAPHY AND MINERALOGY

Ilion Gorge and Steele Creek
This section of road, known as Ilion Gorge, is somewhat narrow and quite winding. The road follows Steele Creek.

Syracuse Fm. (Upper Silurian).
Outcrop (on the right) of gray Syracuse Fm. (Upper Silurian).

Vernon Shale (Upper Silurian)
Outcrop of the red Vernon Shale (Upper Silurian). See Treesh, 1972, for more details. These exposures of the Vernon Shale continue for the next 0.3 mile.

Junction of Route 51 with Jerusalem Hill Road
This section of Jerusalem Hill Road is closed. See Treesh (1972) for more details on the units exposed along this closed road. Continue north on Route 51.

Otsquago Sandstone and Tornado Damage
Short stop. Pull off CAREFULLY to the very wide shoulder on the left . Two items of interest. 1) is the small 15' thick outcrop of Otsquago Sandstone (Middle Silurian, Clinton Group; see Muskatt, 1972, for more details). 2) is the damage to trees caused by a tornado in the late 1980's (1989?).

Bridge over Steele Creek. Oneida Conglomerate
On the left, in the stream, are thick layers of the Oneida Conglomerate (Middle Silurian, Clinton Group; see Muskatt, 1972, for more details).

Historical marker on the right
Historical marker on the right, to mark the place where Eliphalet Remington 2nd made the first Remington gun.

Exposures of Frankfort Shale (Upper Middle Ordovician).
These road cut and stream bank exposures on the left and right, continue for 1.4 miles.

Exposure of glacial fluvial deposit in a sand and gravel pit.

Levee system to right
Behind the houses on the right is the levee system for flood control of the West Canada Creek.

Small exposure of the Dolgeville Fm (Middle Ordovician) on the left.

Abandoned stream meander
On the left for 0.4 mile is an abandoned stream meander of West Canada Creek. The stream channel was diverted by the DOT. Note also the braided nature of West Canada Creek as it tries to adjust to the changes.

Undercutting of glacial material
On the right in the hillside, note the undercutting of the glacial material by a meander of West Canada Creek.

Herkimer Diamond Mines
On the left is one of two commercial collecting localities for the quartz crystals known as "Herkimer Diamonds".

Ace of Diamonds Mine
This is the second commercial site for "Herkimer Diamonds". Note also the exposure of the Little Falls Dolostone (Upper Cambrian) on the left.

Glacial Kame deposit and striations
On the left is a large exposure of a glacial kame deposit. Also of note are the glacial striations on an exposure Precambrian syenite gneiss.

Precambrian syenite gneiss
On the left is another exposure of the Precambrian syenite gneiss. These two exposures are part of an uplifted block of Precambrian bedrock. It is similar to the material exposed on Moss Island (see Muskatt, 1978, for more details). Note also the non-conformable contact of over 1 billion years.

Bridge over West Canada Creek.

Eastern Rock Products, Inc. Quarry.
Entrance on the left for the Eastern Rock Products, Inc. Quarry. Park here. We will be crossing the road (on foot) to enter the quarry. There are no further field stops, and you may leave at your leisure. PLEASE, stay away from the water-filled areas, and DO NOT CLIMB THE QUARRY WALLS.

B3: LATE PLEISTOCENE MELTWATER DRAINAGE THROUGH CENTRAL NEW YORK
Bryce M. Hand
Department of Geology, Syracuse University
When the retreating margin of Wisconsinan ice last stood in central New York, large quantities of meltwater poured eastward across uplands separating north-south valleys occupied by finger lakes. In some places, these ancient meltwater routes are inconspicuous; more commonly, they are impressive gorges produced by vertical incision or waterfall migration. On this trip we will examine channels, waterfalls, dry finger lakes, and remnants of deltas produced during this phase of deglaciation.
The importance of meltwater in the deglacial history of central New York has been recognized for many years. Fairchild (1909; 1932) mapped channel complexes from Batavia to Oneida, relating them to discharge from preglacial lakes north of the Valley Heads moraine (which today dams the southern ends of Seneca, Cayuga, and other Finger Lakes), and to "Great Lakes" flow from the Lake Erie basin and beyond. Sissons (1960) described meltwater scour features and sedimentary deposits between Syracuse and Oneida, and demonstrated that englacial, subglacial, and supraglacial flow were locally important. (These types of flow undoubtedly occurred in our area, but ice-marginal drainage was paramount.) Krall (1966) studied fluvioglacial drainage features in the region between Skaneateles and Syracuse. Other discussions bearing on the Syracuse channels have appeared in guidebooks of the New York State Geological Association (Muller, 1964; Grasso, 1970; Hand and Muller, 1972; Hand, 1978).
Despite the remarkable record of meltwater events displayed in central New York, complete historical reconstruction may never be possible. Lack of continuity is a problem; channels traversing upland regions are interrupted by north-south "through" valleys that held lakes (or ice) when the channels were active. Moreover, many erosional features are products of multiple episodes of ice advance and retreat, each accompanied by meltwater drainage that may or may not have been similar to drainage during other episodes. Constructional features (deltas) are temporally more coherent, in that they all must be products of the final phase of ice withdrawal. However, as drainage patterns evolved in response to changing lake levels or the opening of new escape routes, deltas have been destroyed or modified to the point where their significance is not always clear. Finally, the ever-changing configuration of the ice margin (which often provided one bank for the meltwater stream ) is not well constrained.
The point of this trip is to observe a Whitman's Sampler of the types of evidence that remain. Hopefully, ambiguities generated by the inadequate record will be compensated by the fun of weighing alternatives and identifying fatal flaws in our colleagues' (and your leader's) interpretations.

B3: LATE PLEISTOCENE MELTWATER DRAINAGE THROUGH CENTRAL NEW YORK

STOP 1 Rest Area
View across Tully valley segment of Onondaga valley. This is the southward-directed "stem" of the Y-shaped trough ("through valley") system that will be the focus of this trip; Cedarvale trough can be seen extending northwestward from the three-way junction, but the northeastward continuation of Onondaga valley (toward Syracuse) is not visible from here.
As Wisconsinan ice retreated from the Valley Heads moraine (Tully moraine segment, four miles south of here), proglacial Lake Cardiff was impounded between the moraine and the receding ice front. Initial drainage was southward across the Tully moraine (1200') to the Susquehanna River. Later escape was westward (through Joshua and Navarino Channels) into adjacent lakes controlled by slightly lower segments of Valley Heads moraine.
The focus of this trip, however, will be on still later phases of drainage, corresponding to ice-front positions within about 4 miles of downtown Syracuse (and lake levels below about 900'), when meltwater from as far west as Lake Huron poured through central New York. It was this flow that scoured the Split Rock channels, Pumpkin Hollow, "Syracuse" channels (the several outlets crossing the upland between Onondaga and Butternut valleys), and other prominent canyons across uplands farther east and west.

Crest of moraine
The road follows the crest of the Tully moraine. This is predominantly a kame moraine, composed chiefly of outwash. Irregular topography is due to kettles and (to a lesser extent) channeling.

STOP 2. Hidden Falls Road
Excellent view of the north (proximal ) face of Tully moraine. This steep face, which was banked against the ice, contrasts with the gently sloping (kettled) topography south of the moraine crest. This is the plug that held a lake in Onondaga valley.
Crest of the moraine stands at 1200 ' ; 2 miles north of here, the valley floor is 600' lower. Several hundred feet of unconsolidated valley fill (till, outwash, lake clays, and postglacial alluvium) occur even in the deeper parts of the valley.
Rounded gravels in the roadside exposures are typical of the kame materials making up the bulk of the moraine. Clasts of local bedrock predominate : Lower Devonian limestones and dolostones are especially abundant; brown siltstones from the Hamilton Group are somewhat underrepresented, because they are less durable. Somewhat farther-traveled are red Medina sandstone and white Potsdam(?) sandstone. Gneisses come from the Canadian shield.

Delta remnants
Shortly after turning onto US 20, observe delta remnants in Cedarvale trough. The flat tops of these remnants represent various lake levels.

Navarino Channel
Road descends into and crosses Navarino channel. The lake in Cedarvale/Onondaga valley discharged for a while through this channel, which held lake level at just over 1000'. To the southwest (downstream), Navarino channel terminates in a small delta on the east wall of Otisco valley.

STOP 3 Marcellus Town Dump
This is the entrance to Pumpkin Hollow, easily the largest and most impressive meltwater cross channel in central New York. Carved in Marcellus (black) Shale, Pumpkin Hollow is over 300 ft deep, 500 to 1500 ft wide at the floor, and 3 mi long. It carried Great Lakes drainage from Otisco valley to the head of Cedarvale trough. (Virtually all of this flow had previously entered Otisco valley through Guppy Gulph. )
We have here clear evidence that retreat of Pleistocene ice from the Valley Heads position was interrupted by at least one brief readvance. Three miles north of Pumpkin Hollow begins a group of cross channels and scour-ways collectively called the "Split Rock series." Many of these scour-ways are one-sided, implying that the other bank was the ice itself, and that the axis of flow shifted laterally (northward) as the ice retreated. Like pumpkin Hollow, the Split Rock series carried substantial throughput from farther west, probably including outflow from an early phase of Lake Warren.
The highest of the Split Rock series stands at about 900', whereas Pumpkin Hollow is excavated to 700'. Clearly, Pumpkin Hollow could not have been open when the Split Rock series was active, because drainage would simply have escaped via the lower (Pumpkin Hollow) route. Moreover, incision of Pumpkin Hollow after ice had withdrawn far enough to permit development of the Split Rock series requires readvance to >=900' to initiate cutting of Pumpkin Hollow.
If, as suggested by Calkin and Muller (1992, pers. comm.), the Valley Heads moraine represents the Port Bruce Stade (=14,000 Ka), the Split Rock series is reasonably assigned to ice retreat during the Mackinaw Interstade, and readvance (activating Pumpkin Hollow) to the Port Huron Stade (=13 Ka).
It is not known how far the ice front retreated during the Mackinaw Interstade. It could well have cleared the northern margin of the Appalachian Plateau, permitting an interval of "free drainage" (Erie channel?), as envision ed by Fairchild. The limit of Port Huron readvance is probably defined by the end moraine (eastern equivalent of Auburn/Geneva/Canandaigua moraines) about 2 mi south of Pumpkin Hollow.
Although the Split Rock series is usually envisioned as the product of ice recession, it is probably equally valid to view it in the context of ice readvance. The flow is then seen as being pushed progressively southward and to higher elevations, until (somewhat above 900') it was either stopped or redirected to Pumpkin Hollow.
Disappearing Lake, in the west end of pumpkin Hollow, occupies a shallow basin in the top of the Onondaga Limestone. If time permits, we may consider the origin of this depression and some of the lake's interesting behavior.

Driving through Pumpkin Hollow
After about 2 mi, the valley suddenly widens as the north slope recedes. Krall (1966) has shown that Cedarvale trough once continued northwest (i.e., into the north wall of the valley ), but became filled with till and was not subsequently reexcavated. A well along Seneca Tpk (NY 175) a mile northwest of here (el. 1030') penetrated 200+ ft of drift without encountering bedrock.

Delta Remnants
Road climbs onto remnants of deltas deposited by flow that entered the lake in Cedarvale trough after being discharged from Pumpkin Hollow. Delta sands and gravels are underlain by pink lake clays that can be seen here in the roadside ditch, the gully along old dirt road leading to gravel pit on right, and in a bank on left side of road.

Crossing Delta Surfaces
Crossing delta surfaces at 720', 660', and 600'. All of these deposits relate to flow from Pumpkin Hollow. (Some higher levels, above 780', appear to be scoured till surfaces and small kame deltas from local drainage.) Early (high) deltas were eroded and their materials (in part) redistributed into lower deltas as the lake level fell. Note well preserved distributary channels.

STOP 4 Saunders & Sons Gravel Pit
(PERMISSION REQUIRED)
Sand and gravel are being extracted from the Gilbert-style delta whose topset beds define the 720' and 780' levels. Angle-of-repose foresets dip down-valley (ESE) in a single spectacular set whose thickness reaches 70' or more.
Lake level for the 780' delta was probably controlled by the 770' threshold of the approach to Clark Reservation channel. The 720' delta probably formed after the lake outlet had shifted to the (700') threshold of Nottingham Road channel.
Delta deposits in Cedarvale trough must have formed during the final retreat of ice. Had they formed earlier, they would have been vulnerable to destruction or drastic alteration during subsequent ice advance. Also, it was not until final deglaciation that flow through Pumpkin Hollow became established (recall discussion at Stop 3).
The clast composition of these gravels (pebbles/cobbles of limestone, dolostone, red Medina sandstone, gneiss) indicates derivation overwhelmingly from glacial drift. Pumpkin Hollow, which provided the flow that built the delta, is cut in Marcellus (black) Shale, but there are few, if any, clasts of black shale in this pit. This suggests that Pumpkin Hollow first formed in pre-Port Bruce time, became filled with drift during a subsequent glacial advance, and remained filled until final deglaciation (retreat from the Port Huron posItion). Excavation of the modern gorge would have begun with removal of this drift and its incorporation into the Cedarvale deltas.
The alternative possibility, that pebbles of Marcellus Shale would not survive transport, is rejected because such clasts are very abundant in the extensive 620' delta deposits even farther from source. These shale-rich deposits prove that some deepening of Pumpkin Hollow occurred through bedrock erosion during deposition of the youngest (and lowest) deltas. Even the low delta gravels consist chiefly of "bright" (recycled drift) clasts, most of which were probably reworked from older deltas .

620' Delta Terrace
Driving on 620' delta terrace, which displays many well preserved distributary channels. The delta prograded southeastward, down Cedarvale trough to the 3-way junction of the "Y"-shaped valley system, then northeastward toward Syracuse. Further progradation into the Tully valley "stem" was impossible because Tully valley provided no exit for the water. In this direction, the delta terminates in a primary depositional front.
The outlet for the Onondaga Trough Lake at the time of the 620' delta is uncertain. Grasso (1970) assigned it to an intermediate level in the incision of Rock Cut channel (initial threshold =700'; later lowered to 550'). Though I accept Rock Cut as the probable exit route, there seems no reason for a persistent "hang-up" near 600'. Indeed, the floor of Rock Cut seems to have been lowered suddenly from 700' to 550' (Hand and Muller, 1972). In light of this, I would suggest that Rock Cut and High Bridge channels were clear and over-deepened when the 620' deltas formed, and that tailwater control was established farther east by the 580' floor of Pools Brook channel or by the prevailing level of Lake Iroquois into which Pools Brook channel emptied.

View of Northern part of Onondaga Valley
Gravel operation on far side of valley is in the lowest (520') terrace. Escape of water at this time must have been directly controlled by the level of Lake Iroquois, possibly by way of Erie channel (410').

Inlet of Smoky Hollow
Crossing western (inlet) end of Smoky Hollow. This is the southernmost of the "Syracuse" channels cut into the upland between Onondaga valley and Butternut valley. Smoky Hollow is excavated in Marcellus Shale. Incision began at 900'. The channel floor was at 790' at time of abandonment. Hence, while Smoky Hollow was its outlet, the lake in Onondaga valley at this point varied in depth from about 480' to 370'.

STOP 5 Clark Reservation State Park
The abandoned waterfall at the head of Clark Reservation channel illustrates an efficient and characteristic mode of cutting through the Onondaga Limestone: by headward migration of a waterfall. (Channels in the Marcellus Shale more likely were created by vertical downcutting, i.e., incision.) The bedrock threshold here (770') probably controlled lake level in Cedarvale trough while the delta at Stop 4 (Saunders' gravel pit) was forming.
Though not as high as Niagara (120' vs. 160'), Clark Reservation falls is virtually identical to Horseshoe Falls of the Niagara in terms of both planform and size.
At this Stop we will consider the activation sequence of the "Syracuse" channels. All have dimensions requiring "Great Lakes" (Lake Warren) drainage. All were active in late Wisconsinan time. Most (all?) have had complex histories, involving more than one period of excavation.
Restricted (channelized) flow across the Onondaga/Butternut spur began with Smoky Hollow. Scour began at the 900' level, and the channel was abandoned when its floor (at the west-end entry) had been lowered to 790'. Reworked drift in delta deposits in Butternut valley shows that final excavation involved removal of fill from a channel predating the last glacial override. Origin of the cut-off "meander" loop is not well understood, but relict drift deposits in this loop are further evidence of complex history. The scour and delta surfaces between 800' and 900' in Cedarvale trough probably relate to a gradually falling lake controlled by the Smoky Hollow outlet.
Ice retreat soon opened a more northerly escape route through Clark Reservation, establishing an Onondaga-valley lake level controlled by the bedrock threshold above the falls (770'). Cedarvale deltas tied to this threshold include the one seen at Stop 4. Drainage evidently followed the retreating ice margin northward, scouring to bedrock, until Nottingham Road channel became active. The sill leading to the abandoned waterfall at the head of Nottingham channel stands at 700'.
Intermediate points of stabilization were the two abandoned waterfalls in the south wall of Rock Cut (760', 730'). These falls show that the eastern half of Rock Cut was open at this time. However, as discussed by Hand and Muller (1972), subsequent activation of Nottingham channel would not have been possible unless the western half of Rock Cut remained plugged, and a (drift? ice ?) barrier separated the approach to Nottingham from the two Rock Cut plunge basins. Catastrophic failure of this narrow barrier was invoked by Hand and Muller to clear Rock Cut and High Bridge channels to their present levels, creating prominent deltas at the eastern ends of these channels and abruptly lowering the lake level in Onondaga valley by 100'.
Delta terraces in Cedarvale trough seem compatible with this scenario. They suggest that after a period of gradual decline from about 790' to 700' (corresponding to gradual lowering of bedrock thresholds between Clark Reservation and Nottingham), there was an abrupt drop to 660' - 600'. None of the "Syracuse" channels could have provided suitable control for this latter (very extensive) set of deltas. However, if Rock Cut and High Bridge channels were cleared as proposed by Hand and Muller, they would have provided an over-deepened (slow-flowing) exit route to a level-control point still farther east, namely Pools Brook channel (590') or young Lake Iroquois beyond.
Other questions surround Meadowbrook channel, whose floor elevation (western end) is 550', essentially matching that of Rock Cut. Original cutting of Meadowbrook undoubtedly occurred a long time ago, but its graded floor and mild truncation of drumlins indicate that it carried at least some flow during final deglaciation. How could flow have been forced through Meadowbrook if Rock Cut had already been opened to the same level? (Indeed, a somewhat lower level, since evidently some material has been removed from the floor of Meadowbrook channel.) Hand (1978) invoked an otherwise undocumented oscillation of the ice front to permit clearing Meadowbrook prior to opening the western half of Rock Cut. Subsequent blockage of Meadowbrook by ice was then called upon to reactivate Nottingham Road channel and set the stage for catastrophic flushing of the western part of Rock Cut. A simpler and perhaps better alternative envisions a "base" discharge adequate to have some erosive capability even when divided between two major channels. (Channels east of Limestone valley would have been abandoned by this time, and flow from Rock Cut and Meadowbrook would have escaped directly out the northern end of Butternut valley.)

STOP 6 near Onondaga Resource Recovery Facility
Observe Rock Cut channel: 100-150' deep, 1000' wide (floor), 2 mi long, threshold elevation 550'. Entrance ramp and the Onondaga Resource Recovery facility are directly below where Great Lakes discharge must have flowed in its approach to Nottingham channel. At that time, this (western) part of Rock Cut must have remained full of drift or ice. The postulated barrier that prevented Nottingham discharge from diverting to the (cleared) eastern end of Rock Cut was located just beyond (east of) the Resource Recovery facility. Next come the two abandoned waterfalls spilling over the south wall. These provided the flow that cleared out Rock Cut from here on east, prior to activation of Nottingham channel. A trailer park occupies one plunge basin; the other (upstream) became partial filled by a boulder bar when the barrier failed, and is not easily seen from the highway.
Gravel quarrying operations at the east end of Rock Cut have removed much of the delta attributed to the brief episode of catastrophic discharge attending barrier failure.

Climbing up Delta
You are climbing onto a remnant of the delta deposits dumped into Butternut valley during catastrophic flow from Rock Cut. Butternut Creek subsequently isolated this delta remnant and created the steep slope.
On the right side of the road, property of Dewitt Sportsmen's Club, preserves original configuration of the top of the deposit. Note the adverse slope of the broad distributary-like scour. To construct this "delta" (expansion bar?), flow in Rock Cut must have exceeded 65 feet!

STOP 7 - Top of delta with huge boulders
This is the top of the delta/expansion bar attributed to the Rock Cut flood. In the early 1970's, a large highway cut (now vegetated and uninstructive) exposed the full thickness (50' or more) of the NE-dipping foresets within this delta/bar.
The main point of driving through this development is to admire the 6-foot boulders used as lawn decorations. These particular boulders (chiefly Onondaga Limestone) were swept out of Rock Cut and stranded here on the top of the delta. Most, however, were swept to the lip of the delta, from where they rolled down the delta front to form a layer of 2-6' boulders several feet thick beneath the main foresets. The size of these boulders and the need to push them up the backside of this "delta' helped convince Hand and Muller of the reality of the Rock Cut dam burst.

End

B4: PATTERNS OF PHYLETIC EVOLUTION IN THE TRENTON GROUP
ROBERT TITUS
Oneonta, New York 13820
The Trenton Group has been the subject of 60 years of continuous biostratigraphic study since Marshall Kay began his work during the early 1930's. The unit displays a remarkably rich and diverse fossil assemblage which, along with its facies patterns, is now quite well known. The Trenton Group is thus very well suited for research directed at understanding patterns of evolution. This ongoing research program is currently focused on recognizing patterns of intraspecific clinal variation and relating these to facies change in order to develop comprehensive records of evolutionary events. Two case studies are now complete. Evolution within the crinoid genus Ectenocrinus has been described (Titus, 1989). A similar paper on the brachiopod genus Sowerbyella is pending (Titus, 1992). This field guide will serve as an appendix to both of those papers.

B4: PATTERNS OF PHYLETIC EVOLUTION IN THE TRENTON GROUP

STOP 1. The Napanee Limestone
The strata here are primarily thick bedded, black micrites which have been interpreted as a nearshore lagoon facies. Sowerbyella is abundant. This form has traditionally been identified as s. punctostriatus. It is herein reinterpreted as the quiet water, mud bottom clinal variant of s. curdsvillensis. Examine the brachial interiors and see the preponderance of simple forms. Medial septa can be seen but muscle scars, vascular markings and sub-peripheral thickenings are uncommon. The pedicle exterior usually displays alate corners and a well developed medial fold giving this valve a peaked appearance.

STOP 2. The Kings Falls Limestone
The lower strata here are primarily thick bedded, coarse grained biosparites which have been interpreted as a barrier shoal facies, lying offshore of the Napanee lagoon facies. Toward the top of the outcrop the facies grades into a shallow shelf facies. While, at this location, these strata overlie those of the lagoon facies, presumably there were contemporaneous lagoonal facies elsewhere. Sowerbyella is very abundant at the base of this outcrop. This form is larger than the one in the lagoon facies. Most of the brachial interiors are quite ornate. They have medial septa, muscle scars, vascular markings and subperipheral thickenings. The pedicle exteriors have blunt corners. They don't often show medial folds. Instead they tend to be flattened or broadly rounded. This form has traditionally been identified as S.curdsvillensis. It is herein reinterpreted as the agitated facies clinal variant of a more broadly defined S. curdsvillensis. By collecting enough brachial interiors at these two outcrops, an assemblage of forms can soon be put together that show the gradation between the lagoon and the shoal clinal variants.

STOP 3. The Sugar River Limestone
Climb down to creek and walk to exposure east of and about 50 m below the bridge.
There is a prominent re-entrant below the bridge which can be traced downstream. This is a thick bentonite which lies 10 m (32 ft.) below the top of the Sugar River Limestone. Sowerbyella is rare in the deeper water facies above this bentonite, but common in the shallower facies below. Examine the strata several meters below the bentonite. The common form of Sowerbyella here is the mud bottom, quiet water form. Although some of the brachial interiors are ornate, most are plain. Medial septa are seen but other features are uncommon. The form is relatively small. Pedicle exteriors often display a medial fold and alate corners. This location records a return of both quiet water conditions and the quiet water clinal variant of Sowerbyella. Upstream into the highest strata of the Sugar River Limestone, and for a considerable distance into the overlying Denley Limestone, Sowerbyella is quite scarce. This zone is part of the first Sowerbyella bottleneck.
The next location is designed to display an example of model 3 clinal variation. The middle Trentonian crinoid genus Ectenocrinus occupied a shallow to deep shelf range of environments. Because of bank margin steepening, the deep end of its range was deteriorating while shallowing facies offered opportunities for Ectenocrinus in shallow water environments. The result is a kind of clinal orthoselection.

STOP 4. The Sugar River And Denley Limestones
Park and follow one of the trails down to Roaring Brook and then climb down to the top of Whitikers Falls.
At the base of the falls a re-entrant can be seen. This is the same bentonite which was observed at Mill Creek in Lowville. Here it is also 10 m (32ft.) below the top of the Sugar River Limestone. The bentonite is a marker bed which is found at the same level at all outcrops from Mill Creek, Lowville to Sugar River. It has not been found at Deer River or at any of the Mohawk Valley locations.
Examine the several meters of strata above the falls. Ectenocrinus is represented by moderately abundant columnals. Look carefully as these columnals are small. It is very helpful to bring a water container and pour water on columnal rich beds. This brings out the contrast between the columnals and their micritic groundmass. Ectenocrinus is easily recognized by its trimeric morphology. Each columnal is composed of three elements fused together along faintly visible sutures. The most common form is a triangle with very rounded corners. At first glance the lumina appear to be triangular, and many are. But you will soon notice that many also have very poorly developed 4th and 5th points, along with three long and attenuated points (Fig. 5i-5m). All specimens at this level belong to the species E. triangulus.
Climb to the level above where the trail intersects the stream. Here and for quite a distance upstream Ectenocrinus columnals are different. Now they are generally rounder and the lumina are composed of more equal sized points (Fig. 5s-5v). Forms at this level are intermediate between E. triangulus and its descendent E. simplex. Continue upstream and observe the increasingly abundant columnals of Ectenocrinus. The transition from E. triangulus to E. simplex is not just one of morphology. E. triangulus was a relatively stenotopic form which never became especially abundant. The descendent, E. simplex, was altogether different. It was eurytopic and one of the dominant forms in the upper Trenton Group, a "weed" crinoid. This evolutionary event records an ecological transition from the K-strategist ancestor to the r-strategist descendent.
The last locations are designed to illustrate model 2 examples of clinal variation. Sowerbyella passed through two facies bottlenecks, one at the base of the middle Trentonian and one at the base of the upper Trentonian (Fig. 3, arrows). The best place to study the Sowerbyella of the middle Trentonian is at Mill Creek, Lowville, but as that outcrop extends for such a long distance along the stream, it is not practical to include this location in a one-day trip. We will examine middle Trentonian forms at other locations, stops 5 and 6.

STOP 5. The Denley Limestone
Climb to the exposure immediately above the bridge.
At this level the transition to Ectenocrinus simplex is complete. Virtually all Ectenocrinus columnals, upstream from the bridge, are round with pentagonal lumina (Fig. 5z-5aa). Sowerbyella is not common here but the specimens which can be seen are of interest. They are nearly identical to the quiet water lower Trentonian forms. They have plain brachial interiors; the pedicle exteriors have medial ridges and alate corners.

STOP 7. The Upper Denley Limestone
Park, descend dirt path to outcrop.
The best location to see Sowerbyella next is at the outcrop of the lower Steuben Limestone on Rt. 177 just west of Rodman, but this is too far away for our trip today. The Rodman exposure shows Sowerbyella within the second bottleneck (Fig. 3, arrow). Specimens there are small and have a well developed, broadly rounded medial fold. At Talcottsville we can see Sowerbyella in the barrier facies just below this second bottleneck. The form is abundant up to the base of the falls and then quite a bit less common in the bottlenecking beds above. The specimens here are, for the most part, characterized by well inflated pedicle exteriors which sometimes display the broadly rounded medial folds typical of the second bottleneck. Brachial interiors are generally plain. Notice the magnificent display of large symmetrical ripple marks (pararipples) here.

STOP 8. The Hillier Limestone
Descend to outcrop east of the brook.
The Hillier Limestone is exposed all along Wells Creek and Big Brook. The environment of deposition was quiet deep shelf and the deposits are mostly biomicrites. This location is above the second facies bottleneck and a third species of Sowerbyella is exposed. The form, S. subovalis, is characterized by a greatly inflated pedicle exterior with a broadly rounded medial fold. Brachial interiors are mostly plain. Medial septa are seen, and sometimes poorly developed sub-peripheral folds can be found, but muscle scars and vascular markings are absent. These traits are apparently inherited from the clinal variants of S. n. sp. which made it through the second bottleneck. The ones on Big Brook are larger than their middle Trentonian ancestors.

B5: SURFICIAL GEOLOGY AND SOILS OF SOUTHERN MADISON COUNTY, NEW YORK
Bruce W. Selleck
Hamilton, New York
Introduction and General Bedrock Geology:
Southern Madison County, New York lies south of the Onondaga-Helderberg Escarpment on the northern limits of the Appalachian Plateau. Local relief is approximately 600 feet, with valley floor elevations of 1100 feet in the vicinity of Hamilton, New York. The region is underlain by middle Devonian shales, siltstones and sandstones of the Hamilton Group. These fossiliferous rocks are rather poorly resistant to erosion, and surface outcrops are rare except in stream valleys and along steeply-sloping valley walls. One prominent sandstone unit in the Hamilton Group, the Chenango Sandstone, was quarried in the area as dimension stone. The older buildings on the Colgate University campus are built of Chenango Sandstone quarried on the hill south of the main campus.
Progressively older Paleozoic rock units are exposed to the north, including lower and middle Devonian limestones of the Onondaga and Helderberg Groups, the lower Devonian Oriskany Sandstone, shales, sandstones and dolostones of Silurian age, upper Ordovician shales, and lower and middle Ordovician limestones. Upper Cambrian sandstones and dolostone overly Proterozoic basement rocks in the Mohawk Valley. Lithologies representing all of these rock units can be found within the glacial drift which mantles the bedrock of southern Madison County. The dominant exotic (lithologies other than Hamilton Group) rock types in the drift are limestone, dolostone, chert, sandstone and various Proterozoic rocks of Adirondack origin.

B5: SURFICIAL GEOLOGY AND SOILS OF SOUTHERN MADISON COUNTY, NEW YORK

STOP 1. Madison Street Quarry
This quarry is on private property.
The exposure is at the margin of a kame terrace that continues north along the valley the holds Lake Moraine. Depending on the conditions at the working face, large-scale cross-stratification can be seen, suggesting that this portion of the terrace formed as a lake delta, indicating that ponded water was present to the south. Exposures also contain highly chaotic, poorly sorted debris flow deposits.
Note the composition of the clast suite, rounding of larger clasts, and heterogeneous textures and fabrics.

STOP 2. Valley Overlook on Airport Road
We stop briefly here for a view to the south of the major geomorphic features of the Hamilton area. Note the obvious terraces that flank the lower valley walls, possible glacial trim lines on middle and upper valley walls, and the subdued topography of the valley floor. Note also the feeder canal in the near foreground.

Cross feeder canal from Lake Moraine

Note prominent terrace on left.

STOP 3. Woodman Pond and Chenango Canal
Woodman Pond is a kettle lake that was once used as the water supply of the Village of Hamilton. The village now gains water from wells within the village that are located in highly permeable outwash gravels. This supply, available as a backup, was prone to high algal/organic loads because of overwintering flocks of 1000+ Canada Geese. Note the steep, angle of repose slopes that rim portions of the pond and adjacent marshlands.
Immediately to the west is the Chenango Canal. The canal system in this area was originally developed in the late 1830's for transport of goods from Binghamton to Utica. In the Hamilton area, a system of feeder canals captured south-flowing drainage of the Chenango River, Payne Creek and Kingsley Brook and diverted that water to the north. The Chenango Canal was essentially abandoned as a transportation system in the middle part of the 19th century as railroads were constructed. Portions of the canal system are still used, however, to supply water to the New York State Barge Canal system. The old Chenango Canal at this site carries water from Payne Creek (Lake Moraine) and the Chenango River to Oriskany Creek, which supplies the Barge Canal.

Howard Series soils on left.

Crossing feeder canal from Chenango River.

STOP 4. Randallsville Road Terraces
Two obvious terrace levels are present in this area. Both are underlain by relatively well-sorted gravelly sand, and the material is clearly of fluvial-glacial origin. It has been proposed that the terraces represent either glacial lake deltas or kame terraces, although these may also be erosional terraces formed during late Phase 3 deglaciation.
The soils on the terraces are excellent representatives of the Palmyra series, and are very good agricultural soils. The feeder canal at this site carries water from the Chenango River to the north, skirting the Village of Hamilton, emptying into the Chenango Canal immediately north of the village.

Crossing feeder canal and Chenango River.

Stone house at intersection is made of Chenango Sandstone.

STOP 5. Bewkes Center
The Bewkes Center property was a gift to Colgate from a former chair of the Board of Trustees, E. Garrett Bewkes. We will proceed to the wooded area in the vicinity of Seymour Pond to examine soil profiles in Stockbridge and Volusia series soils, and compare soil profile development in areas of deciduous and coniferous forest canopies.
Seymour Pond may be of kettle origin. However, the surrounding surficial material is ablation till. A more likely origin is the interruption of surface drainage by the configuration of ablation till deposits at the northeastern margin of the lake. The recent sediments in the lake are almost entirely of biogenic origin (diatom and algal/organic). The lake waters are well-buffered, with a pH that varies from 6.8-6.9.

STOP 6. Craine Lake
Craine Lake is an obvious kettle lake surrounded by steep, angle of repose slopes in outwash. The soils developed on the outwash surface are Palmyra series. Craine Lake waters are well-buffered, and precipitation of fine-grained calcium carbonate occurs on aquatic plants during the warm summer months.

Cossitt Concrete Sand and Gravel Plant on left.
The quarrying is developed in outwash.

STOP 7. Horton Road (time permitting)
The fields and pastures of the uplands along Horton Road are underlain by a thin veneer of lodgement till with a high percentage of local Hamilton Group lithologies characterizing the clast suite. Typical Mardin Series soils are developed on the till. These soils are moderately good agricultural soils, but are slow to drain in spring. As we continue east on Horton Road, and onto Preston Hill Road, you will note a number of marshy areas which attest to the rather poor drainage typical of Mardin series soils.

NYSGA 1992 ADK
Meeting Number 64
Adirondack Field Trips
Trip AB-1
Geological Relationships of the Anorthosite-
Mangerite-Charnockite-Granite (AMCG) Suite and
Related Ore Deposits
James McLelland, Colgate University
Trip AB-2
Precambrian Geology of the Ausable Forks
Quadrangle, Northeastern Adirondacks
Philip Whitney, New York Geological Survey, and
James Olmsted, SUNY College at Plattsburgh

AB1:GEOLOGICAL RELATIONSHIPS OF THE ANORTHOSITE-MANGERITE-CHARNOCKITE-GRANITE (AMCG) SUITE AND RELATED ORE DEPOSITS
INTRODUCTION AND GEOCHRONOLOGY
The Adirondacks form a southwestern extension of the Grenville Province (fig. 1) and have been physiographically divided into the Adirondack Highlands (granulite facies) and Lowlands (amphibolite facies) by a broad zone of high strain referred to as the Carthage-Colton Mylonite Zone (figs. 2,3) which is continuous with the Chibougamau-Gatineau line (AB on fig. 1). Together these two zones separate the Grenville Province into two major blocks with the Central Granulite Terrane (CGT) lying east of AB and the Central Metasedimentary Belt (CMB) and Central Gneiss Belt (CGB) lying to the west. Within the southwestern portion of the Grenville Province further subdivisions exist and are shown in figure 3.
As demonstrated by recent U-Pb zircon" and Sm-Nd geochronology summarized (tables 1, 2) by Daly and McLelland (1991), McLelland and Chiarenzelli (1991) and Marcantonio et al. (1990), the Adirondack-CMB sector of the Grenville Province contains large volumes of metaigneous rocks that represent recent (i.e., ca. 1400-1200 Ma) additions of juvenile continental crust. These results (fig. 4) indicate that the Adirondack-CMB region experienced widespread calcalkaline magmatism from ca. 1300-1230 Ma. Associated high grade (sillimanite-K -feldspar-garnet) metamorphism has been fixed at 1226±10 Ma by Aleinikoff (pers. comm.) who dated dust that had been air abraded from metamorphic rims on 1300 Ma zircons. Identical rocks, with identical ages, have been described from the Green Mts. of Vermont by Ratcliffe and Aleinikoff (1990), in northern Ireland by Menuge and Daly (1991), and in the Texas-Mexico belt of Grenville rocks (Patchett and Ruiz 1990). It appears, therefore, that a major collisional-magmatic belt was operative along the present southern flank of the Grenville Province during the interval 1300-1220 Ma and may have been related to the assembly of a supercontinent at this time. More locally, this magmatism and its associated metamorphism, represent the Elzevir Orogeny of the Grenville Orogenic Cycle. as defined by Moore and Thompson (1980). Within the Adirondacks, Elzevirian rocks are represented by 1300-1220 Ma tonalites and alaskites whose distribution is shown in figure 5. The apparent absence of this suite from the central Highlands is believed to be the combined result of later magmatic intrusion and recent doming along a NNE axis.
Within the Frontenac-Adirondack region, the Elzevirian Orogeny was followed by 40-50 Ma of quiescence terminated at 1170-1130 Ma by voluminous anorogenic (fig. 4) magmatism referred to as the anorthosite-mangerite-charnockite- granite (AMCG) suite. The older ages are characteristic of AMCG magmatism in the Frontenac Terrane (including the Lowlands) while the Highlands commonly exhibit ages of 1150-1130 Ma (fig. 5). The large Marcy anorthosite massif (fig. 2) and its associated granitoid envelope have been shown to have an emplacement age of ca. 1135 Ma (McLelland and Chiarenzelli 1990). These ages are similar to those determined (Emslie and Hunt 1990) for the Morin, Lac St. Jean, and several other large massifs farther northeast in the Grenville Province (fig. 1). Rocks of similar age and chemistry (i.e., Storm King Granite) have been described within the Hudson Highlands (Grauch and Aleinikoff 1985). The extremely large dimensions of the AMCG magmatic terrane emphasize its global-scale nature corresponding, perhaps, to supercontinent rifting with the rifting axis located farther to the east. Valley (1985), McLelland and Husain (1986), and McLelland et. al. (l991a,b) have provided evidence that contact, and perhaps also regional, metamorphism accompanied emplacement of hot (-1000°C, Bohlen and Essene 1978), hypersolvus AMCG magmas. Wollastonite and monticellite occurrences related to thermal pulses from AMCG intrusions occur in proximity to AMCG intrusions (Valley and Essene 1980). In the Lowlands, and the Canadian sector of the Frontenac Terrane, monazite (table 1., no. 28), sphene (Rawnsley et al. 1987), and garnet ages (Mezger 1990) all indicate high temperatures (~600-800°C) at ca. 1150 Ma. Rutile ages and Rb/Sr whole rock isochron ages document temperatures not exceeding -500°C at ca. 1050-1000 Ma.
Following approximately 30 Ma of quiescence (Fig. 4). the Adirondacks, along with the entire Grenville Province, began to experience the onset of the Ottawan Orogeny of the Grenville Orogenic cycle (Moore and Thompson 1980). Initially the Ottawan Orogeny appears represented by 1090-1100 Ma hornblende granites in the northwest Highlands. These rather sparse granites were followed by deformation, high grade metamorphism, and the emplacement of trondhjemitic to alaskitic magnetite rich rocks (Lyon Mt. Gneiss of Whitney and Olmstead 1988) in the northern and eastern Adirondacks. The zircon ages of these rocks fall into an interval of 1050-1080 Ma (table 1) which corresponds to the peak of granulite facies metamorphism when crust currently at the surface was at -25 km. Accordingly, the alaskitic to trondhjemitic rocks are interpreted as synorogenic to late-orogenic intrusives. They were followed by the emplacement of small bodies of fayalite granite (ca. 1050 Ma) at Wanakena and Ausable Forks (fig. 2).
Sm-Nd analysis (Daly and McLelland 1991) demonstrates that the emplacement ages of the ca. 1300 Ma tonalitic rocks of the Highlands correspond closely to their neodymium model ages (table 1 and fig. 6a) indicating that these, most probably, represent juvenile crustal additions. As seen in figure 6a, εNd evolution curves for AMCG and younger granite suites pass within error of the tonalitic rocks and suggest that the tonalites, together with their own precursors (amphibolites?), served as source rocks for succeeding magmatic pulses. Remarkably, none of these igneous suites gives evidence for any pre-1600 Ma crust in the Adirondack region and the entire terrane appears to have come into existence in the Middle to Late Proterozoic. Significantly, Sm-Nd analysis for the ca. 1230-1300 Ma tonalitic to alaskitic Hyde School Gneiss (table 1, fig. 6b) demonstrates that it has model neodymium ages and εNd values similar to Highland tonalites. The results are interpreted to reflect the proximity of the Highlands and Lowlands at ca. 1300 Ma. Given this, the Carthage-Colton Mylonite Zone is interpreted as a west-dipping extensional normal fault that formed during the Ottawan Orogeny in response to crustal thickening by thrust stacking (Burchfiel and Royden 1985). East dipping extensional faults of this sort and age have been described by van der Pluijm and Carlson ( 1989) in the Central Metasedimentary Belt. Extensional motion along the Carthage-Colton Mylonite Zone would help to explain the juxtaposition of amphibolite and granulite facies assemblages across the zone. A downward displacement of 3-4 km on the Lowland block would satisfactorily account for the somewhat lower metamorphic grade of the Lowlands terrane.
2015: Stop 8 is incomplete, and Stops 11 and 12 are missing. Probably not a scanning error, as all of the pages appear to be present.

AB1:Geological Relationships of the Anorthosite-Mangerite-Charnockite-Granite (AMCG) Suite and Related Ore Deposits

STOP 1. Trailhead of Roaring Brook Trail on Giant Mt.
The valley of Roaring Brook provides some of the finest exposures of AMCG rocks in the Adirondack region. According to deWaard (1970), torrential rains on June 29, 1963 resulted in flooding that exposed the fresh, smooth outcrops along the book. Presumably, relationships of the sort seen in Roaring Brook would be more widely reported if similar exposures existed elsewhere. On the other hand, the nature of the geology exposed in Roaring Brook suggests that the events that took place here were uncommon, i.e., dikes of several different compositions and/or generations have intruded parallel to the stream valley and a variety of AMCG rock types are represented. A plausible interpretation of the association is that Roaring Brook represents a zone of weakness that has repeatedly served as a magma conduit in the past.
From 1400' to 2000' the brook is underlain by a variety of anorthositic and gabbroic rocks. Generally the gabbroic facies contains two pyroxenes but both augite gabbros and norites are well represented and difficult to distinguish with the naked eye. Near the lip of the high waterfall (note diabase dike in stream bed) a broad (-3m) somewhat irregular, monzonite dike occupies the northwest side of the brook. The contact of this lens-like body with anorthosite is easily recognized once identified. The monzonite contains augite and blue-grey microperthite and closely resembles the anorthosite. The dike is foliated parallel to its margins and crosscuts a N20-40W, 60-80N foliation in the anorthosite. Inspection of the anorthosite reveals that subophitic pyroxenes have not been deformed, and therefore, the foliation was imposed prior to complete solidification of the magma. A reasonable foliation-producing mechanism consistent with these observations would be compaction, within the magma chamber, of randomly oriented plagioclase crystals in a fashion similar to the collapse of a house of cards. Presumably the collapse would be accompanied by filter pressing of pyroxene-rich interstitial liquid. This is consistent with the commonly observed "intrusion" of pyroxene into cracks in plagioclase. It is further suggested here that many of the numerous small pyroxene- and oxide-rich veins, pods, and lenses that characterize the anorthosite massif have this origin. A number of these are present in Roaring Brook.
Proceeding upstream from the lip of the high falls, several steep walled pools are encountered and finally a 3-10 meter-high cliff crosses the brook and results in a second waterfall. At the base of the waterfall there is exposed a dark, meter-wide, eroded dike of pyroxenite. Downstream this dike splays and pinches out, but upstream it defines a pronounced erosional channel in the cliff and then continues upstream for another 30-40 m until it is lost beneath cover. In fact, the dike is discontinuous and is intermittently exposed for almost a kilometer. The chemical composition of the dike is given in table 6. Orthopyroxene dominates the mode but clinopyroxene is also present, as is minor plagioclase and magnetite-ilmenite. Texturally, the orthopyroxenes are large and appear to be of cumulate origin with narrow accumulate overgrowths. Finer-grained plagioclase is interstitial to the orthopyroxenes. Clinopyroxenes occur both as large grains and interstitially, but mainly in the latter mode. Magnetite-ilmenite occurs both interstitially and within pyroxenes but in both instances appear to be late in the crystallization sequence and to occupy spaces whose shape is defined by other minerals.
The pyroxene dike is enigmatic. It is clearly intrusive and was emplaced after the anorthositic rocks acquired their foliation. In several instances xenoliths of anorthosite occur within the dike. Conversely, as noted by deWaard (1979, p. 2072), the anorthositic rocks crosscut the dike at several places, and soft contacts between the dike and country rock are not uncommon, indicating that the rocks are coeval. Because of the dike's composition, it seems unlikely that it was intruded as a liquid. This is consistent with the cumulate and adcumulate textures. About the only remaining possibility is that the dike represents a mobilized, intruded cumulate (deWaard 1970, Ashwal 1978, 1982) together with minor remaining liquid. If so, the intrusion must have taken passively so as to avoid any semblance of preferred orientation among grains. A possible mechanism would be the downward draining of a cumulate layer into an underlying fracture developed in cooling anorthosite. The very high Mg-numbers of the pyroxenes in the dike (Opx-65, Cpx-75, fig. 22) suggest that the cumulate formed early in the fractionation history. Finally we note that least square mixing calculations demonstrate that removal of -95% plagioclase (AN45) from norite yields a composition closely resembling the orthopyroxene dike (table 6). This is consistent with the suggested cumulate origin of the pyroxenite dike.
The smooth outcrop surfaces surrounding the pyroxenite dike are dominated by gabbroic anorthosite transitional to gabbro and provide excellent examples of the composite nature of the anorthositic suite. Several stages in the evolution of the massif are recorded in crosscutting relationships. The oldest anorthosite facies recognizable are coarse grained rafts of blue-grey andesine anorthosite corresponding to the Marcy facies. These are clearly visible on the outcrop. They occur as xenoliths within a subophitic, medium-grained two-pyroxene gabbro, or anorthositic gabbro, which locally, grades into a noritic facies. This, in turn, is crosscut by a fine grained gabbroic anorthosite similar to the Whiteface facies. Elsewhere on the outcrop, the time sequence is partially reversed and the fine grained anorthositic rock is crosscut by gabbroic to noritic facies; however, in all instances, the rafts of coarse, blue-grey anorthosite appear to be oldest rock. An apparently older, fine grained gabbro occurs as xenoliths within fine-grained gabbroic anorthosite near the upper edge of the cliff that defines this level of Roaring Brook.
The Roaring Brook pyroxenite dike clearly crosscuts all facies of the surrounding anorthositic rocks and the foliation within them. However, it is itself crosscut by -10 cm wide dikes of gabbroic material. In addition to previously cited evidence, this observation fixes the pyroxenite dike as coeval with the anorthositic rocks and helps to explain the mutually crosscutting relationships and soft contacts are observed. Note that staining has revealed a small component of monzonitic and granitic material occurring together with the latest gabbroic dikes.
Returning to the trail and proceeding uphill, we cross Roaring Brook and ascend the summit trail to the 2260' (689m) level. Here we leave the trail and descend to water-smoothed pavement outcrops in the brook valley. The outcrops expose a spectacular intrusion breccia consisting of rounded and angular blocks (10-30 cm on average) which include coarse, white anorthosite but consist mostly of grey to black, medium to fine-grained, granular pyroxene-feldspar assemblages. These are set in a medium grained groundmass ranging in composition from gabbroic anorthosite to garnetiferous mangerite and ferrogabbro. These matrix rock types are highly mingled and difficult to separate without the aid of outcrop staining.
Although the intrusion breccia is dominated by dark enclaves, white inclusions of anorthosite are easily recognizable. Less easy to recognize, however, are pink, somewhat glassy, blocks that might be mistaken for garnetiferous quartzite but turn out to be fine-grained, oxide-rich garnetiferous anorthosite or gabbro.
A number of dark inclusions exhibit narrow (~.5 cm), light colored layers. These have traditionally been interpreted as primary in origin and led to the assignment of a metasedimentary origin to the rocks (Kemp 1921, deWaard 1970, Jaffe et.al. 1983, McLelland et al. 1986). However, staining of slabs taken from these occurrences indicate that the layers consist essentially of mesoperthitic syenites and mangerite, some of which can be traced continuously into host rock. Additionally, many of these layers are associated with acicular orthopyroxenes extending outward from the pyroxene-plagioclase assemblage that constitutes the dark layers (fig. 24). The pyroxene-plagioclase assemblages are essentially gabbroic to dioritic in composition with subequal amounts of pyroxene (XMg-OPX = .35-.55, XMg-OPX = .50-.70) and plagioclase (AN25-40). Igneous textures, including acicular orthopyroxene, are common within these layers. On the basis of these textures and compositions, we interpret these layered inclusions as igneous enclaves intruded by parallel veins of syenite and mangerite and incorporated into the mixtures of country rock magmas now constituting the breccia groundmass. The acicular orthopyroxenes are identical to comb textured pyroxenes in demonstrably igneous rocks such as orbicular granites (McKinney 1990) and provide compelling evidence for the igneous nature of these rocks (fig. 24). Note that the often "slumped" configuration of the layering in these rocks is also consistent with their evolution from magmas.
The non-layered inclusions in the Roaring Brook intrusion breccia are also interpreted as igneous in origin. The most compelling evidence for this is the presence of acicular orthopyroxenes within these enclaves (fig. 24), but other observations include rock and mineral compositions which do not correspond closely to possible sedimentary precursors such as calcsilicates, but in many cases are similar to dioritic rocks. Note, for example, that in Adirondack calcsilicates the pyroxenes consist almost solely of clinopyroxene and that these are generally more Mg-rich than the clinopyroxene in the Roaring Brook enclaves (fig. 22). In addition, the enclaves never contain calcite, quartz, wollastonite, garnet, graphite, or phlogopite; all of which are common in calcsilicates. Finally, we note that "soft" and lobate contacts between the enclaves and country rocks similar to those typical of coeval, commingled magmas such as proposed here. Indeed there exist several examples in the brook where dark enclaves can be seen in the process of formation as the result of disruption of masses of mafic rock by felsic country rock. These "soupy" masses are of the same composition as the dioritic mafic enclaves and are believed to represent their sources.
In addition to dioritic to gabbroic enclaves, the intrusion breccia contains a number that are pyroxenitic and, in particular, are clinopyroxene rich. These are shown by filled circles on fig. 25. The most magnesian of all the enclaves is 7-18-89-2 which is a clinopyroxenite (fig. 25). Texturally and compositionally the pyroxenitic enclaves are interpreted as xenoliths of cumulate material caught up and disrupted by ascending AMCG magmas. Consistent with this interpretation is the 130 ppb platinum concentration of 7-18-89-2. This, and other possible cumulate enclaves, are designated as such on fig. 25. Note that these enclaves do not contain acicular pyroxene and consistently exhibit large, interlocking pyroxene grains with minor interstitial plagioclase. Within some of the larger masses of dark material both dioritic and cumulate pyroxenite coexist thus indicating a genetic relationship between the two types.
In order to better constrain the evolution of the enclaves, we have plotted their chemistry in binary variation diagrams with MgO chosen as a common variable (fig. 25), because it, more than SiO2, varies with fractionation in mafic rocks. The most important conclusion emerging from these plots is that magma-mixing appears to have taken place - both with regard to the enclaves and with regard to the breccia matrix. Several of the variation diagrams, and especially SiO2 vs. MgO, show a pronounced linear plot of country rock jotunite, mangerite, and charnockite. We interpret this to mean that the intermediate rock types represent mixtures of the other magmas. Here it must be stressed that the jotunites are not necessarily the most primitive of the felsic rocks; they are likely to be the result, despite their position in these plots, of mixing of ferrodiorites and mangeritic magma.
In the binary plots (fig. 25) the rocks interpreted as cumulates lie approximately along a straight line for most oxide variation. Moreover, they head, in most instances, towards anorthositic and jotunitic rocks. This is consistent with the field-based observation that the (analyzed) examples of these rocks were found in, and collected from, jotunitic and anorthositic matrixes. Therefore, they had no opportunity to mix with granitic material. In addition to this, their cumulate nature, including partial solidification, would have inhibited mixing. However some mixing did take place and this is convincingly documented by plots involving Al2O3 and CaO which show a greater range in the enclaves than in the host rocks.
The dioritic enclaves exhibit substantial scatter in the variation diagrams but appear to have interacted mainly with mangeritic and charnockitic magmas, as is certainly the case with the layered varieties. Chemical analyses are given in table 6 and variation diagrams (fig. 25) demonstrate mixing of the enclaves with mangeritic to charnockitic matrix. The mixing is also recorded by the composition of acicular pyroxenes which become increasingly iron-rich near the contact with the matrix rock, thus establishing a smooth gradient with these less magnesian compositions (fig. 23).
If magma mixing and commingling exist, as described, at Roaring Brook then there are at least three, and probably four or five, magmas that have interacted. These would include charnockitic, mangeritic, anorthositic, and ferrogabbroic to ferrodioritic magmas to the matrix that ascended through the Roaring Brook conduit. The anorthositic and ferrogabbroic magmas appear to have incorporated xenoliths of clinopyroxenitic cumulates which exhibits some interaction with these magmas. The dioritic enclaves are interpreted in the manner of Wiebe (1979) for the Nain anorthositic complex. Here similar dioritic enclaves are interpreted as residual liquids filtered pressed from anorthositic magma by intruding granitic magma. The dioritic magma then chilled against the granite, forming pillows with soft, lobate contacts, etc.. Some mixing between the magmas results in linear arrays in binary variation diagrams, similar to the situation at Roaring Brook.
In addition to the enclaves described above there are present, in the downstream section of the intrusion breccia, layers and sheets of very iron rich (Xmg ~.25-.30) pyroxenite which is associated with the mangeritic rocks. The origin of these sheets is unclear, but by analogy with more magnesian pyroxenites, they may represent mobilized cumulates from the mangerites.
Near the bottom of the downstream section (-700 m) the number of anorthosite xenoliths in the mangerite-jotunitic groundmass increases rapidly until the rock passes into a block structure configuration similar to that commonly developed in the Marcy massif anorthosite.

STOP 2. Split Rock Falls
The roadcut across from the parking area provides evidence for multiple intrusions of anorthositic and gabbroic rock. The dominant rock type is gabbroic anorthosite which encloses altered xenoliths. Subophitic textures are preserved in the more gabbroic xenoliths. Garnetiferous gabbro truncates foliation in some xenoliths and has, itself, a different foliation. Some small xenoliths of anorthosite are elongated and are deformed parallel to the foliation in the gabbroic facies suggesting coeval magmatism. All of the above facies, including the garnetiferous anorthositic gabbro, are disrupted by a more mafic facies similar to Woolen Mill gabbro. Chemical analyses of representative samples are given in table 7. Late mafic dikes (Phanerozoic?) with well developed slickensides cut all other lithologies.
The outcrop not only gives good evidence for the composite nature of the Marcy anorthosite massif, but it also demonstrates the manner in which these rocks can acquire foliation during magmatism and without the need for regional strain. Numerous other localities exist in which different members of the anorthosite suite locally develop foliations which are crosscut by other anorthosite facies. The fact that these rocks involved are clearly contemporaneous, and that the fabrics are strictly local, provide compelling evidence that the foliations developed during composite magmatism when semi-consolidated blocks and magmas underwent differential movement.

STOP 3. Isoclinally folded complex
Long roadcuts in isoclinally folded complex of gabbroic, anorthositic, and granitic rocks.
Although most rocks in this outcrop are highly altered, it affords the opportunity to see the effect of Ottawan deformation on AMCG rocks. Most of the outcrop consists of somewhat gneissic anorthositic gabbro. Garnet megacrysts, several cm. across, truncate foliation and may have grown under static conditions. Large black clots of hornblende contain remnant orthopyroxene cores and may represent giant orthopyroxenes. A representative analysis of the gabbroic phase is given in table 7.

STOP 4. Woolen Mill Gabbro
Park on the right side of the road opposite high roadcut on left. The cut shows metanorthosite intruded by a dark, fine-grained rock, first described by Kemp and Ruedemann (1910) as the "Woolen Mill Gabbro". It is a clinopyroxene-garnet-oligoclase granulite with considerable opaque oxides and apatite, and minor K feldspar and quartz. It contains a few large, uncrushed andesine xenocrysts, probably derived from the host anorthosite. The texture is that of a granulite, but the xenocrysts have apparently escaped recrystallization or grain-size reduction, even along their margins. This peculiar situation may be explained by static recrystallization of an initially fine-grained intrusive rock. The composition of rock (table 7) is that of a somewhat K20 rich (1.20 wt%) ferrogabbro of the type common in the Adirondack Highlands, especially near magnetite-ilmenite concentrations. It also is found associated with anorthosite at stops 7 and 8 and is commonly present as disrupting material in block structure. Woolen Mill gabbro may represent gabbroic anorthosite magma enriched in mafic components by separation of cumulus plagioclase as suggested by mixing calculations (Ashwal 1978).
This is the type locality for deWaard's (1965) clinopyroxene-almandine subfacies of the granulite facies. Typical compositions for Woolen Mill gabbro are plotted in the ACF projection given in fig. 30b, and these make it clear that some changes in composition control the presence of small quantities of orthopyroxene.
Cross the road and examine the outcrops in the stream bed. At the west end of the stream exposures, Woolen Mill gabbro clearly crosscuts anorthosite, and veins and dikes of the gabbro extend into the anorthosite. Within the anorthosite there is well-developed "block structure" where several types of anorthosite have undergone brittle fracture before being intruded by thin dikes or veins of mafic as well as felsic material. Some of these veins are identical to the mafic granulite in the roadcut (and at the west end of the stream exposure) and are part of the anorthosite suite. Some of the disrupting material is anorthositic gabbro more commonly associated with the anorthosite as on Giant Mt. or Lake Clear. In addition, a variable amount of granitic material is present in many of the veins as revealed by straining. The relationships here suggest formation of a plagioclase-rich cumulate, which was then fractured and intruded by a later mafic differentiate. This apparently brittle behavior suggests a relatively shallow depth of intrusion. Notice also the very large (up to 10 cm) giant orthopyroxenes that occur in the anorthosite, especially near the contact with Woolen Mill gabbro.
The anorthosite in the stream bed contains the characteristic post-metamorphic alteration assemblages of calcite ± chlorite ± sericite that are commonly seen as late-stage, hairline vein fillings or as alteration products of Fe-Mg silicates throughout the Adirondacks (Buddington 1939; Morrison and Valley 1988b). Average values of δ18O and δ13C for calcite are +12.6 and -2.2 permit, respectively, which suggests that the alteration fluids were deep seated in origin and exchanged with igneous as well as metasedimentary rocks. These veins are related to the formation of some high-density. CO2-rich fluid inclusions and the temperatures of alteration are estimated at 300°-500°C (Morrison and Valley 1991, 1988b).
The retrograde fluids that have infiltrated the anorthosite to precipitate calcite have not significantly altered its oxygen isotopic composition. Values of AΔ(calcite-plagioclase) range from 0.9 to 6.6, indicating that the isotopic composition of the alteration minerals was controlled primarily by the hydrothermal fluid and that the δ18O of the host rock remained largely unchanged due to low fluid/ rock ratios.
Values of δ18O (plag) for the "blocks" and their host anorthosite at this outcrop range from +8.5 to +9.3. In general, the metanorthosites in the NE part of the Marcy massif are somewhat more isotopically heterogenous than those in the northwestern part of the massif, but they shows the same roughly 2.5 permit enrichment in δ18O relative to "normal" anorthosites worldwide (Morrison and Valley 1988a).

STOP 5. Hulls Falls (Bridge).
Park on south side of road. Keene Gneiss at Hulls Falls
Here the East Branch of the Ausable River has exposed a typical section of hybrid anorthosite-mangerite-charnockite gneiss referred to by Miller (1918) as Keene Gneiss. The water smoothed outcrops consist of irregular, garnetiferous interlayers of plagioclase-rich and microperthite-rich gneisses with little actual mixing between them. The whole rock chemistry of several of the granitic fractions is given in table 8 (nos. 1 and 2 from Hulls Falls, no. 3 from Alden Lair):
Within the granitic facies of Keene Gneiss, blue-grey xenocrysts of andesine (An48) are readily visible (Fig. 5, McLelland and Chiarenzelli 1990, reproduced in this volume) and commonly exhibit lighter-colored reaction rims of more sodic plagioclase similar in composition to that in the mangeritic host (AN30) . It is difficult, without staining, to distinguish the granitic and anorthositic facies of Keene Gneiss; however the anorthositic facies tend to weather whiter than the granitic facies, and the presence of quartz is diagnostic of the latter.
As Keene Gneiss is followed across strike, and towards anorthosite, the granitic fraction becomes increasingly rich in andesine xenocrysts and xenoliths of anorthosite. Ultimately the granitic fraction constitutes no more than an interstitial filling between andesine grains and the gradation into anorthosite is essentially complete (see fig. 4, McLelland and Chiarenzelli 1990).
The origin of Keene Gneiss seems quite clearly to be the result of commingling and hybridization between anorthositic, mangeritic, and charnockitic magmas. The high iron, titanium, and magnesium concentrations of the granitic fractions may be the result of mixing with late mafic liquids from the anorthosite. Such mixing may be responsible for the zone of mafic mangerite, gradational into jotunite, within the Tupper-Saranac complex that Buddington (1939) and Davis (1970) referred to as transition rock. In such instances magma mixing would be more complete and the resultant rock would be more homogenous than Keene Gneiss.

STOP 6. Cascade Slide Xenolith from the Picnic Area.
Walk south across talus slope to remains of dam at base of waterfall. From this point, climb the wooded slope to the east of the falls. Use extreme caution! This is a very steep climb for about 60 m, and there are many loose rocks. In the stream bed above the falls there are several xenoliths and schlieren of marble ± calcsilicate, surrounded by anorthosite. The largest of these bodies measures approximately 30 x 200 m in exposure, is compositionally zoned, and contains several unusual minerals. Most notably, the xenolith contains sanidinite facies index minerals wollastonite, monticellite (Mo92-89), and akermanite as well as cuspidine, harkerite, vesuvianite, and wilkeite (Kemp 1920; Baillieul 1976; Tracy and others 1978; Valley and Essene 1980b). Other minerals present include tremolite, garnet (Gr80-18, And80-15), spinel (Mg73), calcite, forsterite (Fo92), magnetite, clinopyroxene scapolite (Me78-50), quartz, and sphene.
Field relations, deformation and geochronology make it clear that these marble bodies were entrained within the anorthositic magma before the peak of granulite facies metamorphism. The exact timing of intrusion vs. regional metamorphism is still a matter of debate. We favor pre- rather than syn-metamorphic intrusion, but in either case it is certain that both anorthosite and marble experienced the pressures and temperatures of granulite facies metamorphism (Valley and Essene 1980b). Thus, the mineralogy of these bodies may be used to study the P-T fluid conditions of granulite facies metamorphism. The origin of these minerals, which we believe was at low P and high T, is irrelevant in this regard because of the pervasive nature of the granulite overprint.
Several factors combine to make the Cascade Slide xenolith an unusually advantageous locality for fluid studies: 1) On a scale of 0.1 km the field relationships are relatively clear; a complex calcsilicate body is surrounded by anorthosite, so that any fluids infiltrating the xenolith must have passed through the anorthosite. 2) Mineral assemblages in the calcsilicates include many that either buffer or restrict fH2)O and fCO2. 3) There is a large contrast in δ18O values between anorthosite (δ18O=9.7 permil; Taylor, 1969; Morrison and Valley, 1988) and the core of the xenolith (δ18O up to 26.1). Thus the unusual character of this body makes it a sensitive monitor of fluid history.
Solid-solid mineral reactions at Cascade Slide indicate that P and T attained at least 7.4 kbar and 750°C, respectively (Valley and Essene 1980b; Bohlen and others 1985). Valley and Essene (1980b) describe assemblages of akermanite + monticellite + wollastonite with equilibrium metamorphic textures as well as symplectic intergrowths of wollastonite and monticellite. At these temperatures and pressures, the presence of wollastonite, monticellite or akermanite requires that log fCO2 be ≤4.35, ≤3.32, or ≤2.5 respectively.
Further evidence that granulite facies fluid infiltration has not been important at Cascade Slide comes from oxygen isotopes (Valley and O'Neil 1984; Valley 1985). Any fluids (H2O or CO2) passing through the xenolith would first have passed through the surrounding anorthosite (δ18O=9.7). Subsequent exchange with the calcsilicates (δ18O=17.6 to 26.1) would tend to homogenize this large premetamorphic difference with the result that δ18O in the xenolith would be reduced. The highest values of δ18O (26.1) in monticellite marble are thus very restrictive to theories of fluid infiltration and require fluid/rock ≤0.1.
Three lines of evidence argue against the presence of fluid during the granulite facies metamorphism at Cascade Slide: 1) Assemblages of monticellite + forsterite + diopside +calcite +spinel plot in the fluid-absent field, including that if a fluid had existed. PH2O + PCO2 ≤0.4 kbar. 2) The large gradients in buffered values of fCO2 across the body and the fragile nature of the buffering assemblages would have been erased by C02 infiltration. even by quantities as low as CO2/rock = 0.001. 3) The preservation of high δ18O in the core of the xenolith and the sharp gradients of up to 18 permil/15 m would all have been homogenized if either H2O or CO2 had infiltrated the xenolith in quantities greater than fluid/ rock - 0.1. These results are all consistent with the polymetamorphic history proposed by Valley (1985).
Monticellite has also been found at Westin Mines (5 km to theE of Cascade Slide) where magnetite skarn replaces marble at the contact of the anorthosite massif (Valley and Graham, 1991 ). This locality is on private property and won't be visited. Magnetites from marble at this deposit were the first to be analyzed for oxygen isotope ratio by ion microprobe with accuracy of ±1‰ (1σ). This analysis yields spatial resolution as small as 2µm and has reduced sample size by 11 orders of magnitude relative to conventional techniques, permitting new studies of oxygen diffusion, fluid exchange. and Adirondack cooling rate.

STOP 7. East side of Lake Clear.
Anorthositic and Related Mafic Rocks.
This stop consists of a series of low, ledge-like outcrops along the northeast side of Rt. 30. The exposure provides excellent examples of block structure and crosscutting relationships between a variety of anorthositic facies, including Marcy-type, foliated gabbroic anorthosite, gabbro, and mafic ferrogabbro. Outcrop relationships clearly indicate that the anorthositic rocks have been invaded and disrupted by gabbro and ferrogabbro (CpX>Opx) which exhibits ophitic to subophitic texture and contains both small plagioclase grains as well as large (up to 10 cm) grains of blue-grey andesine believed to have been plucked from the anorthosite. The mafic content of the gabbro varies from about 25% to 75% and at the mafic-rich end it grades into oxide-bearing ferrogabbro. Blue-grey andesine xenocryst are common in the ferrogabbros as are Fe, Ti-oxide minerals which cause these rocks to be magnetic. Close inspection suggests that mafic concentrations can commonly be traced back into plagioclase-rich zones where they merge with subophitic interstitial materials suggesting filter pressing.
At the southernmost end of the series of outcrops there is developed block structure of coarse, Marcy anorthosite with blue-grey andesine disrupted by gabbroic and ferrogabbroic material which exhibits "lobate" contacts with the anorthosite, suggesting coeval magmatism. Near the northern end of this outcrop the ferrogabbro becomes exceptionally mafic and includes megacrysts of blue-grey andesine. Narrow, crosscutting veins of sulfide-bearing ferrogabbro are present in the outcrop and some parallel the road along shear zones which are associated with local mylonitization.
To the north, along the series of low outcrops, there is developed more disruption of Marcy-type by gabbroic material which, locally, is the dominant rock type in the outcrop. Commonly, plagioclase laths in the anorthositic rocks exhibit parallel orientation which appears due to magmatic processes and may vary from block to block. Medium grained, light grey leuconoritic xenoliths also occur. Approximately 5O meters from the northern end of the series of outcrops a variety of xenoliths are encountered including a 10 cm long rectangle of green clinopyroxenite. A few feet farther north are several xenoliths of foliated white, finegrained anorthosite to gabbroic anorthosite. Poorly foliated fine grained, leucocratic anorthosite xenoliths are also present. An exceptionally good example of ferrogabbro-ferrodiorite crosscuts the outcrop here (see sample LKCL4, table 9 for analysis). This and other mafic dikes and sheets in the anorthosite are believed to be the result of filter pressing of interstitial magma from anorthosite rocks at various stages during fractional crystallization.
In the last 50' of the outcrop plagioclase xenoliths and xenocrysts increase as the rocks pass into homogenous, fairly typical Marcy facies with large blue-grey andesine in a finer grained white to grey matrix. Although some of this matrix may be due to crushing, it is believed that most consists of originally finer grained anorthosite intrusive into, and disrupting, the Marcy facies.
Approximately 0.1 mile north along the highway there is exposed a gabbroic anorthosite that disrupts coarser grained anorthosite. A thin (1-2 cm) vein of magnetite-pyroxenite crosscuts, parallel to the road for the length of the outcrop and appears to displace some poorly understood layering in the anorthositic rocks. A green, diopsidic xenolith of calcsilicate is present on the top of the outcrop.
Farther to the north, across a driveway, and opposite a tennis court, there is exposed a long, high roadcut of coarse grained anorthositic gabbro gradational to gabbro with local concentrations of large, blue-grey andesine megacrysts. These rocks, are crosscut by a finer grained, more leucocratic anorthosite that is locally dominant and by a late, pink granitic dike. Several rounded xenoliths of calcsilicate occur in the outcrop.
Among the many valuable relationships to be seen at this stop are the crosscutting phases of the anorthositic series with the oldest, as at Giant Mt., being the coarse Marcy facies. In addition, the existence of fine grained, anorthositic magma is further confirmed. Late gabbro and mafic gabbro are better developed here than at Giant Mt. and the gradation of these rocks to ferrogabbro is well documented on the outcrop. These iron-rich mafic phases represent residual liquids, together with some cumulates, filter pressed during fractional crystallization of anorthositic gabbro. Figure 26 summarizes the trends recorded by these dikes and provides compelling evidence for an Fe-enrichment, Fenner trend in the anorthositic series. The large circles in 36 wt% SiO2 in figure 26 represent oxide concentrations in an experimental glass produced by Eppler and corroborate the existence of liquids of these extreme compositions, i.e., exceptionally enriched in TiO2, FeO, and P2O5. Mass balance analysis (fig. 27) of these trends (Moore et al. 1992, Denny et al. 1992, Ashwal 1978) demonstrate that plagioclase-dominant fractionation accounts for the indicated trends. It is thought that liquid immiscibility may occur at SiO2 concentrations somewhat less than 36 wt% to produce magnetite-ilmenite deposits such as those at Tahawus. Chondrite-normalized REE concentrations calculated from the mass balance model correspond almost exactly to observed trends and demonstrate the validity of the model (fig. 28).
dark layers. At both the eastern and western extremities of the outcrop there occur facies typical of the least contaminated granite. These consist of pink, medium grained alaskite whose major mafic mineral is magnetite. Small quantities of diopside and sphene are also present, probably due to contamination. The feldspar in these rocks consists almost wholly of mesoperthite or microcline perthite indicating that these are hypersolvus granites.
Initially, McLelland (1986) interpreted these alaskites as metavolcanic members of the 1130-1150 Ma AMCG magmatism. However, U-Pb zircon data acquired from this outcrop, as well as three others in the northern and eastern Highlands, yield well constrained ages of ca. 1060-1080 Ma (table 1). The zircons from these rocks exhibit morphological, zoning, and systematics characteristics that are typical of zircons crystallized from melts (fig. 29) rather than those grown during metamorphism. Therefore, the 1050-1080 Ma ages given by these zircons date the time of crystallization of the zircons, and the alaskite, from a magma. Clearly, this magma could not have been extruded as a volcanic, since an abundance of uncontested evidence dictates that the entire region was undergoing granulite facies(Ottawan) metamorphism at 20-25 km during this time interval. Therefore, the alaskites are best interpreted as synorogenic, hypersolvus granites intruded at considerable depth during the late stages of the Ottawan Orogeny. Placing the intrusive events at the late stages of orogeny helps to explain the highly variable development of strain-related fabrics in these rocks, some of which are devoid of any evidence of strain but do contain good igneous textures. An intrusive origin for the alaskites is also consistent with their hypersolvus feldspars which require temperatures of -800°C at pressures of 7.5-8 kb and their unusually high Zr-concentrations of up to 2000 ppm, (table 3) which, for rocks of this composition require temperatures of ∼1000°C (Watson and Harrison, 1983 ). Both these constraints require temperatures well above those of regional metamorphism (fig. 13) and preclude a metamorphic origin for these rocks. Finally, note that the alaskitic and related granitic gneisses contain no vestige, or even hint, of any primary volcanic characteristics.
Two major reasons for suggesting a metavolcanic origin for these rocks were 1) the extreme sodic (up to 10-11% Na2O) or potassic (up to 10% K2O) concentrations of some members which could be accounted for by alteration at the surface, and 2) the presence of semiconformable interlayers, including low-Ti magnetite deposits. The extreme compositions which are not uncommon in acidic volcanics of the S.W. United States and may be either original or due to metasomatic processes operating during late magmatism. While extrusive examples are most commonly described, intrusive examples of extreme compositions also exist in intrusive suites, and may be either primary or due to metasomatism. Examples of both possibilities are well documented in the literature with the late Himalayan leucogranites being an example of extreme original magmas (Leforte, 1981), and the Wilson Ridge Pluton of Nevada (Smith et at. 1990) serving as an example of metasomatic alteration at depth.
Figure 5a shows the distribution of the 1050-1080 Ma alaskitic gneisses in the northern and eastern Highlands. Whitney and Olmsted (1989) have thoroughly described these rocks and given the name Lyon Mt. Gneiss to the association. From the foregoing presentation, it appears that the Lyon Mt. Gneiss is not part of the AMCG suite.

STOP 8. Alaskite?
2015: Although no pages appear to be missing in the pdf, descriptions of stops 8, 10 and 11 are partly or totally missing. The description below is probably that of STOP 8, but how much was omitted is unknown.
dark layers. At both the eastern and western extremities of the outcrop there occur facies typical of the least contaminated granite. These consist of pink, medium grained alaskite whose major mafic mineral is magnetite. Small quantities of diopside and sphene are also present, probably due to contamination. The feldspar in these rocks consists almost wholly of mesoperthite or microcline perthite indicating that these are hypersolvus granites.
Initially, McLelland (1986) interpreted these alaskites as metavolcanic members of the 1130-1150 Ma AMCG magmatism. However, U-Pb zircon data acquired from this outcrop, as well as three others in the northern and eastern Highlands, yield well constrained ages of ca. 1060-1080 Ma (table 1). The zircons from these rocks exhibit morphological, zoning, and systematics characteristics that are typical of zircons crystallized from melts (fig. 29) rather than those grown during metamorphism. Therefore, the 1050-1080 Ma ages given by these zircons date the time of crystallization of the zircons, and the alaskite, from a magma. Clearly, this magma could not have been extruded as a volcanic, since an abundance of uncontested evidence dictates that the entire region was undergoing granulite facies(Ottawan) metamorphism at 20-25 km during this time interval. Therefore, the alaskites are best interpreted as synorogenic, hypersolvus granites intruded at considerable depth during the late stages of the Ottawan Orogeny. Placing the intrusive events at the late stages of orogeny helps to explain the highly variable development of strain-related fabrics in these rocks, some of which are devoid of any evidence of strain but do contain good igneous textures. An intrusive origin for the alaskites is also consistent with their hypersolvus feldspars which require temperatures of -800°C at pressures of 7.5-8 kb and their unusually high Zr-concentrations of up to 2000 ppm, (table 3) which, for rocks of this composition require temperatures of ∼1000°C (Watson and Harrison, 1983 ). Both these constraints require temperatures well above those of regional metamorphism (fig. 13) and preclude a metamorphic origin for these rocks. Finally, note that the alaskitic and related granitic gneisses contain no vestige, or even hint, of any primary volcanic characteristics.
Two major reasons for suggesting a metavolcanic origin for these rocks were 1) the extreme sodic (up to 10-11% Na2O) or potassic (up to 10% K2O) concentrations of some members which could be accounted for by alteration at the surface, and 2) the presence of semiconformable interlayers, including low-Ti magnetite deposits. The extreme compositions which are not uncommon in acidic volcanics of the S.W. United States and may be either original or due to metasomatic processes operating during late magmatism. While extrusive examples are most commonly described, intrusive examples of extreme compositions also exist in intrusive suites, and may be either primary or due to metasomatism. Examples of both possibilities are well documented in the literature with the late Himalayan leucogranites being an example of extreme original magmas (Leforte, 1981), and the Wilson Ridge Pluton of Nevada (Smith et at. 1990) serving as an example of metasomatic alteration at depth.
Figure 5a shows the distribution of the 1050-1080 Ma alaskitic gneisses in the northern and eastern Highlands. Whitney and Olmsted (1989) have thoroughly described these rocks and given the name Lyon Mt. Gneiss to the association. From the foregoing presentation, it appears that the Lyon Mt. Gneiss is not part of the AMCG suite.

STOP 9. Long Roadcut of Mangerite
Mangerite dated at 1134±4 Ma
A long roadcut through grey-green mangerite extends for several hundred feet along the south side of the highway. The rock is typical of Adirondack mangerite and consists dominantly of coarse (1-3 cm) grains of mesoperthite (ternary feldspar) together with 5-10% quartz. A chemical analysis is given in table 3 (AC=85-6). Interstitial to the mesoperthite grains are intergrowths of iron-rich clinopyroxene and orthopyroxene which exhibits an elongate habit suggestive of acicular texture. The pyroxenes occur in strained, elongate concentrations that are commonly accompanied by fine-grained plagioclase (AN25-30). At contacts between the plagioclase and mesoperthite a great deal of myrmekite is developed at the expense of the mesoperthite. In addition, a separate, fine-grained micropegmatitic intergrowth of quartz and perthite are also interstitial to the large grains of mesoperthite. Present in most thin sections are xenocrysts of andesine (AN45) which exhibit characteristic magnetite-ilmenite clouding. These grains are strongly zoned outward to AN25-30. Blue-grey andesine xenocrysts can be seen on the outcrop but are made best visible by straining.
The textures described above record a complicated history for these rocks. It is not known whether the large grains of mesoperthite represent cumulates in the conventional sense, but they were clearly intruded by other magmas subsequent to solidification. At least one batch of this was anorthositic and the other granitic. In the process of some of the hot magma may have experienced supercooling, thus giving rise to acicular orthopyroxenes. Coeval magmatism is also indicated by the fine grained, leucocratic dike at the southern end of the roadcut. This lithology not only crosscuts the mangerite but immediately to the north (left) occurs as an angular xenolith in the mangerite demonstrating contemporaneity. A chemical analysis of the dike yields: SiO2-67.8, TiO2-.88, Al2O3-16.11, Fe2O3-4.65, MgO-.72, CaO-1.23, Na2O-2.8, K2O-5.55.
Near its southern termination, the mangerite is crosscut by an irregular dike of green pyroxenite (table 9). This dike, which is similar in some respects to the orthopyroxenite-rich dike at Roaring Brook, consists principally of iron-rich clinopyroxene with a Mg-number of 25, corresponding in composition to clinopyroxene in the mangerite. While the origin of the dike remains uncertain, it is difficult to account for its monomineralic nature in any way but as a mobilized cumulate.
Interestingly, the mangerites at this locality, as well as many others in the region, do not develop garnets, although their mineralogy (feldspar, oxides, pyroxene) and Mg-numbers appear permissive of garnet formation and nearby granitoids are garnetiferous. The reason for the absence of garnet is best explained by differences in bulk chemistry as discussed by deWaard (1965). As shown in fig. 30a sample AC-85-10 from this outcrop plots well below the plagioclase-orthopyroxene joint in an ACF project. In contrast, garnetiferous charnockites and mangerites plot above this join. The position where AC-85-10 plots is not determined by Al2O3 alone but by the concentration of other oxides as well (note especially the importance of high Na2O and K2O in reducing the A-value in the projection). By implication, the mangeritic rocks are within the orthopyroxene-plagioclase subfacies of the granulite facies (deWaard 1964).
Although mangeritic rocks may look simple, they generally are not and, as in this case, commonly exhibit features related to magma commingling. These complicated features, as revealed by microscopic study, and require further investigation.

STOP 12. Pink Hornblende Granite (1098±4 Ma)
This streaky, pink hornblende granitic is typical of the younger granitic rocks of the Highlands. A chemical analysis is given in table 3 (AM 86-6) and the mineralogy of the rock is dominated by mesoperthite and quartz with only a few small grains of sodic plagioclase and <5% hornblende. Buddington and Leonard (1962) mapped this body of granite as younger than, and crosscutting, the mangerites and quartz-mangerites of the AMCG suite. This field-based interpretation is consistent with geochronology, and the intrusive contact passes through the sand and water covered valley between this stop and the next outcrop due north along Rt. 30.
Figure 5b shows the distribution of the younger granitic rocks whose ages fall into the 1090-1100 Ma range. Within the area shown on fig. 5b, several occurrences of these rocks have been recognized but they do not represent a significant percentage of the designated area. These rocks are enigmatic, since they do not fit into any major chronological or petrologic group. At present, the sample base for this group is too limited to draw major conclusions on their origin, and additional study is required.

STOP 14. Gated road to Cheney Pond.
Large boulders on either side of road. Magnetite-Ilmenite Ores at Sanford Lake
According to Stephenson (1945) the Sanford Lake magnetite-ilmenite ores were discovered in 1826 when a party, entering from Indian Pass, encountered the, now mined-out "Iron Dam" of ore which extended across the Hudson River at the present site of the Tahawus Club. Mining began in the 1830's and by the 1840's was supplying ore for the first cast-steel plant in America (Adirondack Iron and Steel Company, Jersey City, N.J.). Production halted in 1858; was reorganized as the Macintyre Iron Co. in 1894; and resumed production in 1906. Despite extensive planning, little ore was produced or shipped. In 1908 a French metallurgist, A. Rossi, employed by the Macintyre Iron Co., discovered the suitability of titanium as a white paint pigment. Continued transportation difficulties plagued mining operations until 1941 when N.L. Industries, Titanium Division, acquired the property. By 1942 ilmenite concentrates were being shipped. The mine was extensively developed during, and after, World War II where it was exploited for titanium, and a railroad was built to North Creek. Since approximately 1980, mining activity has slowed, and at present a skeleton crew works the deposits for a variety of purposes. The main pit is flooded, and water level is rising rapidly.
The ore in the Sanford Lake district consists of titaniferous magnetite and hemo-ilmenite in subequal amounts with ilmenite generally being slightly more abundant. Lamellae of ilmenite in magnetite originated via subsolidus oxidation-exsolution (Haggerty 1976). Green pleonaste spinel commonly forms as an exsolution product in magnetite. Iron sulfides occur as accessory phases. Both titanomagnetite and hemo-ilmenite form abundant small, rod-like inclusions in associated plagioclase sometimes rendering them black and opaque. The average composition of titanomagnetite and hemo-ilmenite in the principal ore deposits is given by Kelly (1979) as Mt61Usp18 and Ilm94Hm6 respectively.
The ore in the Sanford Lake district occurs in two major modes: 1) as lean or disseminated ore gabbro, and 2)as massive, rich ore generally in anorthosite but locally within gabbro. As pointed out by all students of these deposits, the lean ore within gabbro is gradational into the host rock (with which it is commonly conformably layered, Ashwal 1978, p. 106) but in anorthosite the ore exhibits sharp contacts relative to host rock. Note that ore-bearing gabbro also sharply crosscuts the anorthosite. The massive ore exhibits sharp contacts with host anorthosite and with disseminated ore in anorthosite. With the exception of apatite-rich, and possibly nelsonitic, rocks near Cheney Pond (Kolker), the concentrations of P2O5 in the ore deposits is strikingly low. Whole rock chemical analyses are given below.
Strip mining and diamond drilling have confirmed that the ore tends to be concentrated in lenses measuring 600-700 m in length and 150-300 m in width. It is not known whether this conformable configuration is the result of crystal settling, intrusion, or the accumulation of immiscible oxide-rich liquids. This uncertainty extends to the petrologic details of the origin of the deposits, although the evolution of these rocks is understood in the broad perspective. As seen at Stops 7 and 8, Day 1, the late differentiates of the anorthosite move toward pronounced enrichment in Fe, Ti-oxides thus yielding liquids of increasingly ferrogabbroic composition together with associated ultramafic cumulates. As seen in table 10, the gabbro at Sanford Lake, and other occurrences of magnetite-ilmenite ore, is not unlike the Woolen Mill gabbro, which is representative of late anorthositic differentiates. Except for P2O5 the Sanford Lake gabbro is also similar to Buddington's (1953) mafic gabbro form McCauley Mt. Comparisons of this sort suggest that the ores at Sanford Lake are the result of progressive differentiation of magmas residual from gabbroic anorthosite and that, at some point, these magmas became so enriched in iron and titanium that they either precipitate magnetite-ilmenite cumulates (Ashwal 1978) or immiscibility of Fe-Ti oxide and silicate melts occurs (cf. Stephenson 1945; Kelly 1979). In the former case the conformable layers represent cumulate beds and in crosscutting ore horizons represent mobilized cumulates. In the latter case, both layered and crosscutting configurations can be explained on the basis of an immiscible Fe-Ti oxide liquid. A third possibility exists which is a combination of the foregoing alternatives, i.e., magnetite-ilmenite could begin to precipitate relatively early in the history of the complex but continued fractionation might still result in liquid immiscibility at a later stage.
Arguments against liquid immiscibility at Sanford Lake have commonly focused on the low concentrations of apatite in these rocks (note, however, the exception of nelsonite at Cheney Pond). However, as pointed out by Lindsley (1992) P2O5 and apatite do not necessarily travel with the immiscible oxide melt. Moreover, P2O5 may not be a direct cause of liquid immiscibility but, rather, may play an indirect role in keeping the magma molten until Fe-Ti-O networks in the melt can no longer coexist with the silicate networks and immiscibility occurs. Because of this late magmatic association, apatite and immiscibility would appear to be more directly connected than may actually be the case.
The stop at Sanford Lake takes advantage of excellent relationships exhibited in boulders on either side of the Calamity Brook Road at the gated entrance to the Cheney Pond Road. Over three dozen large, fresh boulders from the mines provide outstanding exposure of anorthosite, gabbro, ore-bearing gabbro, and massive ore crosscutting anorthosite. Several boulders containing both anorthosite and ore exhibit what appear to be coeval and pillowing relationships between the two phases. In other instances massive ore and ore-bearing gabbro crosscut anorthosite. A number of boulders show irregular oxide-rich veins, some of which clearly contain separate fractions of oxide and silicate suggestive of liquid immiscibility. Many of the ore boulders contain xenoliths and enclaves of anorthosite and xenocrysts of andesine some of which are black due to oxide inclusions. Several boulders of good Marcy-type anorthosite are present as are some sheared, hornblende-bearing gabbroic anorthosite.
Relationships seen in these boulders demonstrate that the Fe, Ti-oxide ore derives from the gabbros and bears intrusive relationships to the anorthosite. Polished slabs show the oxide phase to intimately penetrate and disrupt the anorthosite on a scale smaller than the grain size of magnetite and ilmenite in adjoining ore. This suggests that the oxide intruded as a liquid and this observation, together with evidence of liquid immiscibility in similar rocks (Lindsley 1992), lead us to suggest that most, if not all, of the Sanford Lake ores were emplaced as immiscible liquids. Turn around and return to intersection. Turn south on main road (side trip to visitors overlook at open pit mine). Intersection with Blue Ridge Highway; turn east (left).

AB2A: PRECAMBRIAN GEOLOGY OF THE AU SABLE FORKS QUADRANGLE, NORTHEASTERN ADIRONDACKS
Philip Whitney
Geological Survey, New York State Museum
James Olmsted
Center for Earth and Environmental Sciences
State University of New York College at Plattsburgh
INTRODUCTION AND GEOLOGICAL SETTING
The Ausable Forks quadrangle (Figs. A1, A2) in the northeastern Adirondack Mountains, near the border of the Marcy anorthosite massif, contains four major rock units. All four units display mineral assemblages consistent with granulite facies metamorphism, except for local retrograde assemblages in the vicinity of late, brittle faults.
Several large, roughly domical, bodies of metanorthosite and gabbroic anorthosite gneiss are the structurally lowermost exposed rocks. Overlying the domical metanorthosites is a complex of layered metamorphic rocks several kilometers thick, which dip away from the metanorthosite domes. Foliation and compositional layering in these rocks are parallel or subparallel to the foliation in the outermost parts of the anorthosite domes. The layered complex, shown in white on Fig. A2, comprises the metasedimentary rocks, described in more detail below, as well as metaigneous rocks including granite (locally charnockitic), ferrodiorite, monzodiorite, anorthosite and gabbroic anorthosite gneisses. Larger bodies of metaigneous rocks are shown separately in Fig. A2.
The third, structurally uppermost, major unit in the quadrangle is a heterogeneous quartzo-feldspathic gneiss that crops out over an area of nearly 1000 km2 in the northeastern Adirondacks. This has been named the Lyon Mountain Granitic Gneiss by Postel (1952); we have shortened this to Lyon Mountain Gneiss (LMG) because it contains substantial amounts of rock that are not of granitic composition (cf Stops 4 & 5). This unit underlies much of the northern third of the Ausable Forks Quadrangle, and forms the core of a tight, upright, north plunging synform (the Ausable Forks Syncline of Balk, 1931) in the central third (Fig. A2). North of the Ausable River, the LMG is host to numerous small, and a few rather large, bodies of low titanium magnetite iron ore that were worked throughout much of the nineteenth century and the first half of the twentieth (Gallagher, 1937 ; Postel , 1952).
The first three units are intruded by coronitic olivine metagabbro, which occurs as several large bodies in the southern half of the quadrangle, and as smaller pods and lenses in the layered rocks throughout the area. The metagabbro ordinarily retains primary igneous textures in the interiors of all but the smallest bodies, and is metamorphosed to garnet amphibolite or mafic granulite near the contacts.
On this trip we will first examine a representative section of metasedimentary rocks exposed in a stream cut (Stop 1), followed by a look at the underlying domical metanorthosite (Stop 2). Stops 3-5 are roadcut exposures of various facies of the Lyon Mountain Gneiss; Stop 6 is an unusual fayalite granite found within the Lyon Mountain but with uncertain relationship to it. Time permitting, we will return to the metasedimentary rocks at Stop 7.

AB2A: PRECAMBRIAN GEOLOGY OF THE AU SABLE FORKS QUADRANGLE, NORTHEASTERN ADIRONDACKS

STOP 1. Gelina Basin section of metasedimentary rocks.
The road forks at this point, with the R fork leading steeply uphill. There may be a gate across the L fork. This is private property, owned by Ward Lumber Co. in Jay. If you come here on your own, get permission. We will park here and proceed on foot up the R fork (if you have a 4WD vehicle, this road can be driven). Set your altimeter for 1280 feet. After about a mile, the road ends at a hunting cabin ("Camp Pissonya") in a clearing. Walk to the R of the cabin past the outhouse, where you will find a trail that follows the top of a steep bank. Follow the trail S to about 1800 feet altitude, and work your way down the bank to the stream at the bottom. This unnamed, N flowing stream drains a modified cirque (labeled Gelina Basin on the 15' quadrangle map) on the north flank of Jay Mountain. We will attempt to hit the stream at about 1725 feet elevation and traverse upstream over a well-exposed section of NNE-striking metasedimentary rocks.
1730-1750' (altitudes approximate) Calcsilicate rocks with diopside and wollastonite, locally rusty weathered, with quartzite layers.
1750-1760' Strongly foliated, interlayered amphibolite and calcsilicates, overlain by coarse, rusty, calcite-diopside-phlogopite-graphite marble.
1780-1820' First of three waterfalls. At the base of this falls, layered diopside-wollastonite calcsilicates (WoDi) and quartzite are exposed. The caprock is tremolite-bearing quartzite; just above this is Mg-rich enstatite (En95)-diopside (Di97)-tremolite-quartz rock.
1830' 5' cascade over diopsidite and diopsidic marble with thin quartzite layers.
1840-1870' Interlayered metasedimentary rocks (diopsidites and WoDi) and thin amphibolites.
1880-1900' Amphibolite, overlain by metasedimentary rocks, including a calcite-diopside-wollastonite-grossular-idocrase marble at the base of a second waterfall. The cap of this falls is a dark, feldspathic diopsidite with locally abundant sphene. The amphibolite here may be a sill or dike of olivine metagabbro satellitic to the larger body exposed just upstream.
1910-1960' Third falls. The lower part of the falls is a cascade over banded WoDi rock; the upper part is olivine metagabbro locally mixed with granitic gneiss. The gabbro contact here appears to have a steep easterly dip, truncating the more gently dipping metasedimentary layers. Thin sections of the WoDi rock here show thin rims of grossularitic garnet around wollastonite, possibly a result of the reaction wollastonite + plagioclase = grossular + quartz.

STOP 2. Metanorthosite of the Jay Dome
Park off road on L, just upstream from the covered bridge. Walk S up the road to the first outcrop on the R. This glacially polished and striated outcrop is relatively fine-grained anorthosite containing xenoliths of coarse, blue-gray anorthosite. One of these is surrounded by an envelope of anorthositic gabbro. This "block structure" is indicative of the complex magmatic history of the anorthosite.
The outcrops in the river are dominantly light-colored, fine grained anorthosite with scattered blue-gray andesine megacrysts and a few blocks of igneous-textured anorthositic gabbro. Small, irregular dikes of gabbro and of a mafic rock rich in pyroxene and Fe-Ti oxides cut the anorthosite and have been deformed and metamorphosed along with it.
Unmetamorphosed late Proterozoic basaltic dikes occupy fractures or faults paralleling the river. These are mildly alkaline within-plate continental basalts, possibly emplaced during extension of Grenvillian crust prior to the opening of the Proto-Atlantic Ocean (Coish and Sinton, 1992).
On the opposite side of the river (unless water levels are very low, we will have to cross the bridge to reach these outcrops) there is a textbook example of small, NE-trending faults offsetting mafic layers or dikes in the anorthosite. Also present here is a large xenolith of very fine-grained, pyroxene rich metasedimentary rock.
We will have lunch at this stop before proceeding.

STOP 3. Lyon Mountain Gneiss, granitic facies.
A series of large outcrops, slightly back in the woods, extends for over 0.1 miles along the N side of the road from this point. These outcrops are fairly representative of the granitic facies of the Lyon Mountain Gneiss. Notice the considerable variability in both texture and in the nature and amount of mafic minerals (hornblende, pyroxene, biotite, magnetite). A few thin amphibolite layers are present. At the eastern end of this series of outcrops, diagonally opposite the entrance to the Chesterfield Rod & Gun Club, is a roadcut of highly sheared gneiss showing two foliations on the weathered surface. The rock here lacks K feldspar, and appears to be the of the trondhjemitic (LAG) facies, although untypical.

Clintonville had population over 10,000
During the height of iron mining activity in the latter part of the 19th century, Clintonville is reported to have had a population of over 10,000.

Turn L onto old railroad grade (unpaved).
Caution: do not attempt this in a vehicle with low road clearance.
The thick, sandy glacial sediments here are deltaic deposits of the Lake Coveville stage.

STOP 4. Lyon Mountain Gneiss
Lyon Mountain Gneiss, leucocratic albite gneiss facies.
Park vehicles in wide, flat area to R of road. Walk back about 1/4 mile along a series of outcrops on the N side. This is the trondhjemitic (LAG) phase of the Lyon Mountain Gneiss. The rock consists of about 70% albite (ca Ab95), 20% quartz, 5-10% dark green clinopyroxene with up to 40% acmite end member, and lesser amounts of magnetite and titanite. K feldspar is conspicuously absent; these rocks typically contain less than 0.5% K2O (Table 3). Toward the E end of the outcrops, more mafic layers display complex folding.
A sample from this outcrop yielded a U/Pb zircon age of 1057±11 ma (McLelland et al. 1988). This age, which coincides with the age of peak granulite facies metamorphism in the Adirondacks, is interpreted by Chiarenzelli and McLelland (1991) as the age of igneous emplacement, making the Lyon Mountain Gneiss a syntectonic intrusive suite. This conflicts with the evidence cited by Whitney and Olmsted (1988) indicating a supracrustal origin. Possible resolutions of this conflict will be discussed.

STOP 5. Epidote-bearing layered gneisses.
The outcrops on the N side of the road are unique within the Lyon Mountain Gneiss complex. The conspicuous cm-scale layering consists of alternating layers of microcline granitic gneiss and a rock rich in quartz, epidote, and chlorite (replacing??). Clinopyroxene, amphibole (pleochroic from blue to green), scapolite, plagioclase, and sphene are present in some layers. The delicate layering, combined with the overall felsic composition, suggests a protolith of water-laid sediments and felsic tuffs.

STOP 6. Fayalite Granite.
Park on the N side of Route 9N near the foundation of a former restaurant, previously known as the Lima Club and the Red Bandana. The outcrops of interest are an old quarry in the woods well to the north of the road. Our approach will depend on where we can get permission from landowners. The rock is a massive to slightly foliated, dark green fayalite-ferrohedenbergite granite. In thin section, the feldspar is a magnificent flame perthite. The fayalite granite is apparently surrounded by Lyon Mountain Gneiss, although we have been unable to find an exposed contact. Interestingly, it yields an older U/Pb zircon age (1089±6 ma; Chiarenzelli and McLelland 1991) than the more strongly deformed Lyon Mountain. It is also more reduced than the Lyon Mountain, with oxygen fugacity close to the fayalite-magnetite-quartz buffer.

Outcrops on the R are the leucocratic albite gneiss.
The small outcrops on the R are the leucocratic albite gneiss facies of the Lyon Mountain, here with conspicuous thin mafic layers.

STOP 7. The Snake
No hammers, please! Small outcrops on the E (left) side of the road show intricately folded marble, calcsilicates, amphibolite and granitic gneiss of the Rocky Branch Complex on the west limb of the Au Sable Forks synform, not far from the contact of the Jay Dome to the West. This very photogenic outcrop, informally known as "The Snake", has now been partially obscured by debris from construction upslope.

AB2B: GEOLOGY OF THE WILLSBORO-LEWIS WOLLASTONITE ORES
James F. Olmsted
S.U.N.Y. Plattsburgh
Philip R. Whitney
N.Y.S. Geological Survey
Paul w. Ollila
7 Newton St.
Shrewsbury, MA 01545
The presence of wollastonite near Willsboro in the northeastern Adirondacks has been known since the early nineteenth century (Buddington, 1977). Without an obvious use, the occurrence was of little interest except as a mineralogical curiosity until the early 1950's when the Cabot Corporation began mining it for use as a filler and ceramic base. Product development resulted in such uses as a tempering agent in ceramics, flux in welding rods, an alloying agent, an extender in plastics and, recently, as a substitute for short fiber asbestos. With the opening of the large open pit mine in Lewis, ten miles SW of Willsboro, in 1980, the original Willsboro mine was closed. Both properties are now owned by NYCO Minerals, Inc.

AB2B: GEOLOGY OF THE WILLSBORO-LEWIS WOLLASTONITE ORES

STOP 8. WILLSBORO MINE
This will be a long stop during which we will e xamine relationships at surface exposures near the middle and lower portals, and then proceed northward across the overlying units about 600 m where we encounter the "midsection'' anorthosite unit (see figs B1 and B2). We will then return to the mine via a slightly more westerly traverse to see additional exposures of the units overlying the ore, including a fine example of coronitic metagabbro.
CAUTION: Please do not under any circumstances go underground.
NYCO has graciously given us permission to visit these mines, but this privilege will be withdrawn in the event of an accident to any of our visitors. If you wish to follow this trip on your own, first get permission at the NYCO offices in Willsboro .

The gate to the Lewis Mine is on the L.
Get permission; then proceed up gravel road to the mine.

STOP 9. LEWIS MINE
While the immediate geologic setting of the Willsboro deposit is well known (Putman, 1958; DeRudder, 1962; Olmsted and Ollila, 1988), that of the Lewis deposit is less clear due to lack of natural exposures in the immediate vicinity. The orebody strikes roughly E-W and dips, on the average, gently south, approximately parallel to the topographic surface. On the west side of the open pit, where the ore is close to 25 m thick, it is overlain by charnockitic gneiss, whereas north and east of the pit the overlying rock is mainly anorthositic. Based on drilling data and temporary exposures within the mine, the footwall appears to be amphibolite and gabbroic anorthosite gneiss.

John T. Bursnall, Editor
St. Lawrence University
Canton, New York, 13617
Additional copies may be purchased from the Executive Secretary,
Center for Earth and Environmental Science, State University of New York,
College at Plattsburgh, Plattsburgh, NY 12901
EDITOR'S PREFACE AND ACKNOWLEDGMENTS
The 65th Annual Meeting the NYSGA, held at St. Lawrence, is now behind us and the guidebooks are, at last, about to go out (!). But before they do I wish to thank the numerous people who helped with the planning, organization and running of the conference. In particular I should like to mention the trip leaders, since without their willing support the meeting would not have been possible; also all those who travelled the distance, on an unavoidably inconvenient weekend for some, and braved the characteristic vagaries of North Country weather at this time of year - bright sun (if not downright warm) on the first day and torrential rain (or was it sleet?) on the second. Particular thanks are also due to: Jim Olmsted, Executive Secretary of the Association, for keeping us to appropriate deadlines early in the organizational process; Kurt Salzburg and the staff at St. Lawrence's Conference Services for their invaluable assistance; St. Lawrence Food Service for their great banquet; Alice Quackenbush for controlling the processing of applications, mailings, phone queries, and everything else; Mike Whitton for hours of , cutting and pasting'; and last, but far from least, all of the Geology Club members who willingly helped with registration, welcoming party, stuffing packages, and all the other time-consuming and sometimes onerous tasks that are necessary for the smooth running of a conference.
Finally, a separate note of thanks must go to Dave Franzi and Ken Adams who, together with Don Pair, put on a last minute trip when it was realized that Jim Street would not be able lead his intended trip - one that was to have included a summary of some of Jim's research over the past decade or more.
This short editorial piece is followed by the dedication of this volume in Jim's memory.
DEDICATION
John Bursnall
Canton, NY
We, the staff, students, and alumni of the Geology Department at St. Lawrence University wish to take the occasion of the 65th Annual Meeting of the New York State Geological Association to dedicate this Guidebook, and this conference, to our long time colleague, teacher and friend Dr. James S. Street. Jim's thoroughness, graciousness, and strong scholarly interest in his North Country surroundings are a model for us all, and have been so time and again.

A1: PRECAMBRIAN GEOLOGY OF THE NORTHWEST ADIRONDACK LOWLANDS: A STRATIGRAPHIC VIEWPOINT
WILLIAM F. DELORRAlNE
Zinc Corporation of America
Balmat, NY 13609
JAMES D. CARL
College at Potsdam
Potsdam, NY 13676
The idea of widespread preservation of a coherent stratigraphic sequence in middle Proterozoic rocks in the Adirondack Lowlands has been challenged from several standpoints. Workers in the Adirondack Highlands, and elsewhere in high grade Grenville terrane, have drawn attention to the extent of tectonic realignment that has accompanied folding, ductile deformation and metamorphism. Rock units that were originally discordant have been swept into into parallelism to form "straight gneisses" that resemble a layered sequence. Sequences of metasedimentary rocks have been obscured by the size, volume and frequency of igneous intrusions. Contacts between intrusive and sedimentary rocks have been obliterated by tectonism, the acquisition of gneissic foliation and by metamorphic differentiation. Further complications are introduced where lithologic units have been disturbed or cut out by faulting, and where slivers of much older rocks have been thrusted into the terrane. Thrusting and stacking of crustal segments from southeast to northwest is proposed to have occurred in large parts of Grenville terrane in Canada (Davidson, 1986). For a general review of field and textural criteria used to recognize intense deformation and tectonic realignment, see the summary by Passchier and others (1990).
The Adirondack Lowlands consist chiefly of recognizable metasedimentary rocks and extensive units of fine grained gneisses whose protoliths are a matter of controversy. Meta-intrusive rocks here constitute a much smaller proportion of outcrops than in the Adirondack Highlands, and the intrusive bodies are generally smaller in size. Ductile deformation has been extensive in some rock types, particularly the marbles (now annealed?), Hyde School Gneiss and the Huckleberry Mountain granitic gneisses (Tewksbury and others, 1993, and this guidebook). Nonetheless, primary features have been preserved that include stromatolites in carbonates and cross bedding in quartzites. Dikes, apophyses, aplite veins, pegmatites and phenocrysts are preserved in certain meta-intrusive bodies. Highly ptygmatic and cross cutting migmatite veins have not been realigned to parallelism in Popple Hill Gneiss, and rocks in some of the fault panels mapped by Brown (1989) preserve a stratigraphic succession comparable with that elsewhere. The case for pervasive tectonic realignment that mimics, but does not represent, a true stratigraphic succession must be demonstrated for local areas in the Lowlands.
Stratigraphic principles are applicable where widespread rock units are shown to be older than the meta-igneous rocks that intrude them. Zircons from the widely distributed Popple Hill Gneiss, portions of which are regarded as meta-volcanic by Carl (1988), have a U-Pb age of 1214 +/- 21 Ma (Carl and Sinha, 1992) and a whole rock Rb-Sr age of 1297 +/- 41 Ma (Grant and others, 1984). Zircons from another possible meta-volcanic unit, the Hyde School Gneiss, range in age from 1219 +/- 52 Ma to 1284 +/- 7 Ma, but ages of 1236 +/- 6 Ma and 1230 +/- 30 Ma for unzoned zircons from two of the bodies have been considered representative (McLelland and others, 1992). Intrusive rocks in the Lowlands generally fall into the range of 1170-1130 Ma as is the case for anorthosite, mangerite, charnockite and granite members of the AMCG intrusive series in the Highlands (McLelland, 1986).
The above remarks are made in the aftermath of a large number (more than 40!) of published U-Pb zircon ages (McLelland and others, 1988; McLelland and Chiarenzelli, 1990; 1991; Chiarenzelli and McLelland, 1991; McLelland and others, 1992) which have had great influence on the understanding of Adirondack geology, particularly in the Highlands. The paper by McLelland and others (1992) on a major Lowland rock type, the Hyde School Gneiss, is of concern because it proposes to overturn a set of stratigraphic conclusions established over decades of field mapping and mining exploration. Hyde School Gneiss, long regarded as a basal stratigraphic unit throughout the Lowlands, is now proposed to be an intrusive igneous rock with no stratigraphic significance. The possibility that meta-volcanic rocks could constitute a large proportion of Adirondack rock types is relegated to the backwater of "phase II" in a three-phase summary of the history of Adirondack conceptual schemes (McLelland, 1991). That argument is the subject of a field trip to be held on the weekend following the 1993 NYSGA meeting. Interested readers can obtain copies of the guidebook from the organization known as Friends of the Grenville (FOG, which does not necessarily reflect the state of mind of its members). For the Lowlands and for this guidebook, we plan to "dress up" the corpse of "phase II" which is characterized by paradigms of stratigraphy and stratigraphic correlation. We address some of the issues in the field stops described below.

A1: PRECAMBRIAN GEOLOGY OF THE NORTHWEST ADIRONDACK LOWLANDS: A STRATIGRAPHIC VIEWPOINT

STOP 1. SW end of the Reservoir Hill body
Black Lake member of Lower Marble formation, SW end of the Reservoir Hill body of Hyde School Gneiss.
The purpose of this stop is to examine the Black Lake member of Lower Marble formation that overlies the Reservoir Hill body of Hyde School Gneiss. Marbles here are identical in lithology with those exposed west of the Beaver Creek lineament. The marble terrane west of the lineament was labelled the "Black lake Metasedimentary Belt" (Engel and Engel, 1953), and the lowermost member of Lower Marble derives its name from that area (deLorraine and Carl, 1986). Black Lake marbles are quite distinct from the marbles upsection. They are characterized by the presence of ribbed, rusty-weathered, calc-silicate gneiss bands, disseminated black tourmaline, feldspar grains, phlogopite and granular diopside (Fig. 1). Also common are coarse graphite, scattered quartz "eyes" and intercalated quartzites. Massive rusty diopside rocks and a thick, homogeneous calcitic marble unit occur west of the Beaver Creek lineament. Absent at stop 1 is the sillimanite-garnet gneiss that typically surrounds bodies of Hyde School Gneiss. It is informally labelled the Sawyer Creek gneiss after thick exposures near Sawyer Creek along the margin of the California body of Hyde School Gneiss (deLorraine and Carl, 1986).
Note the minor folds in the marbles. Are one or two phases of folds present? One might interpret an early phase defined by rootless, isoclinal intrafolial folds that are refolded by more or less upright to overturned disharmonic folds.
At first glance, one might regard Hyde School Gneiss at this locality as containing few amphibolite layers. When viewed from the rear, i.e. from the high bedrock knobs to the north, the massive outcrops of leucogneiss can be seen as steeply dipping slabs or layers, thanks to the presence of deeply weathered amphibolite layers. Foliation in the leucogneiss is folded about the Reservoir Hill anticline, suggesting that an earlier deformational fabric has been refolded. The anticline is interpreted as a doubly-plunging, southeast overturned, second phase sheath fold that is coeval with the Great Somerville anticline of Buddington and the Sylvia Lake syncline in the Balmat-Edwards mining district.
An important point to make here is the consistent and predictable appearance of Hyde School Gneiss below the Black Lake member of Lower Marble formation. Upsection of this member is a scapolite prism marble that separates the member from an overlying gray and white banded marble called the Marble City member (Fig. 1). The Marble City member will be examined in stop 3. It lacks the rusty weathering gneissic bands and disseminated feldspar observed in the Black Lake member.
We emphasize the contrasting carbonate and calc-silicate rock types because they might otherwise appear to constitute a homogeneous sea of undistinguished marbles. The marbles should not be dismissed simply as "tectonic grease." Stromatolites have been locally preserved, and the persistency of contacts between relatively thin members for great distances has provided information about the geometries of major folds. Mapping of the thin units is the basis for structural work and zinc exploration in the Sylvia Lake syncline. Unit 6 in the Upper Marble formation, for example, has several 10 to 30 ft thick subunits of distinctive texture and composition that can be traced around the Sylvia Lake syncline by drill core from Balmat to the Hyatt mine, a distance of at least 8 miles (12.9 km). Contacts between rocks of undoubted metasedimentary origin are conformable with each other and, in many cases, with the overlying and underlying gneissic formations. These contacts are interpreted as reflecting original compositional and lithologic differences; that is, they constitute a stratigraphic sequence.
Thus, the appearance of Hyde School Gneiss at a predictable horizon is regarded as the consequence of depositional patterns modified to various degrees by metamorphism, folding, ductile deformation, ductile faulting and partial melting. Stop 12 will add basaltic intrusion to the list, but these late dikes are not to be confused with an earlier amphibolite layering.

STOP 2. Scapolite marble with basalt dike
Scapolite marble member of the Lower Marble (with basalt dike).
Rock here overlies the carbonate and rusty gneiss of stop 1. This characteristically pitted, light gray member or horizon of the Lower Marble formation consists of scapolite- bearing, graphite-phlogopite marbles with quartz segregations. It can be traced southwest of the Gouverneur body of Hyde School Gneiss to aid in defining the "Great Somerville anticline" of Buddington that parallels Route 11 through Somerville village. Scapolite is gray because of finely disseminated graphite; it varies from coarsely bladed to small elongate crystals.
The 1 m thick basaltic dike within the scapolitic marble is N 60 E, vertical and undisturbed in contrast to the highly segmented and metamorphosed dikes to be seen at stop 3. These and other NE-trending Lowland dikes may have been produced by Late Precambrian rifting and the opening of the Iapetus Ocean basin. The dikes are generally vertical, fine-grained, undeformed, amygdaloidal, and show chilled borders against the wall rock. They must have intruded brittle rocks at shallow depths. Many have undergone saussuritization and contain epidote veinlets. They intrude all Precambrian rocks in the Lowlands, but do not intrude patchy remnants of overlying sedimentary rock such as the Cambrian Potsdam sandstone. They show deep weathering (some are altered to hematite) where exposed near the pre-Upper Cambrian unconformity.
Narrow dikes like this one are likely to be strongly saussuritized and to yield unreliable directions of paleomagnetization. Seven samples from thicker, well-crystallized dikes, however, show a grouping of north-seeking poles in the southeast quadrant of the lower hemisphere of an equal area net. Books and Brown (1983) were unable to match the grouping with data from dikes in Ontario.
A hydrothermal event (phase 4 of Brown, 1983) may have reset the ages of many basalt dikes. K-Ar ages from one dike of 405 +/- 11 and 440 +/- 10 m.y. obtained on feldspar and pyroxene respectively (Brown, 1975) are not compatible with the pre-Upper Cambrian age required by field relationships. Ages for Ontario dikes ranging from 600 to 800 m.y. (park and Irving, 1972) are likely to be representative of Lowland dikes, and the ages of 405 and 440 m.y. may approximate the time of hydrothermal activity (Brown, 1983). Hydrothermal activity is also proposed as the cause for alteration along joints that has produced epidote and reddish feldspar in some Lowland gneisses.
Badger (1993) has studied the largest of the Lowland dikes, a 14 km long, NE-trending dike that cuts Precambrian rocks including the Hyde School body of Hyde School Gneiss (see map of Brown, 1988). The dike shows alkalic affinities and has uniform chemical composition. Tectonic discrimination plots are indicative of within-plate magmatism and OIB-type (Ocean Island Basalt) mantle plume source. These dikes may be related in origin to late Precambrian, rift-related magmas of the Ottawa Graben, the eastern Adirondack Mountains and western Vermont.

STOP 3. Train Wreck outcrop
Marble City member of Lower Marble and the broken basaltic dike of the "train wreck outcrop."
The road cut is located just south of the SW end of a major regional fold hinge, the Reservoir Hill anticline. Numerous minor folds in the marble may reflect the proximity of that anticline. Reconstruction of a refolded isocline suggests an "S" asymmetrical sense when viewed to the north; the "S" is consistent with the location of the fold on the eastern limb of the Reservoir Hill anticline. Axial surfaces of many minor folds have shallow to moderate dips to the west, perhaps giving an indication of the degree of overturning of the anticline.
This massive, coarsely crystalline, blue-gray banded calcitic to slightly magnesian marble is graphic and phlogopitic. We correlate it with Brown's (1989) unit "mm" in the northern part of the Richville quadrangle and North Gouverneur area. Marbles at stops 1 and 2 are lower in the section.
This roadcut was proposed as the type section for a single northwest Adirondack carbonate-bearing formation named the Gouverneur Marble (Wiener and others, 1984). We regard it as a member of the Lower Marble Formation. The rock was quarried throughout the area for building stone in the early 20th century. Note the small town glory that once was Gouverneur (informally called "Marble City") as preserved in the upper levels of the downtown buildings.
The dike here is metamorphosed and disrupted in contrast to the dike at stop 2, but displacement is not great in view of the extensive folding in the marble. The antiform observed in the outcrop probably existed in its present form when the dike was intruded (Schoenberg, 1974; VanDiver, 1976). The lower part of the dike appears to have been a sill, whereas the upper part cuts across the banding in the marble. Possibly the subsequent refolding, as indicated by the shallow broad syncline to the right of the dike, may have caused brecciation and displacement of the dike blocks.
The dike blocks are recrystallized and re-equilibrated near the contact with the marble. They contain little or no plagioclase, abundant diopside and melonitic scapolite with lesser microcline, sphene, tremolite, biotite, quartz, opaque, tourmaline and apatite.

STOP 4. Steer's Head outcrop
Steer's Head outcrop where Antwerp-type granitoid gneisses have intruded the Lower Marble.
Gneisses of granite to granodioritic composition comprise a string of large, disconnected, boudin-like masses that extend from Antwerp village northeasterly for 40 km to Moss Ridge-Battle Hill near Gouverneur village. These rocks intrude chiefly the Marble City member of Lower Marble, but near Antwerp village they intrude Popple Hill Gneiss. Radiometric ages include an Rb-Sr whole rock age of 1197 +/- 53 Ma by Douglas Mose (in Carl and others, 1990), and a zircon U-Pb age of 1183 +/- 7 Ma by Jeff Chiarenzelli (in McLelland and others, 1992). These intrusions are slightly older than most anorthosite, mangerite, charnockite and granite (the AMCG intrusive suite of McLelland, 1986) in the Highlands.
Antwerp granite at this outcrop has surrounded and isolated a segment of cream colored marble that is shaped like a "steer's head" (resembling an illustration in a Zane Gray western novel). Major minerals include microcline, plagioclase, quartz, hornblende and biotite. Minor minerals include tourmaline, magnetite, ilmenite, apatite, zircon, titanite and secondary chlorite. Note the veins of quartz and tourmaline in symplectic intergrowth.
Intrusive origin is not easy to demonstrate for many Lowland gneisses, given the multiple deformation and high-grade metamorphism. Dikes and sills within marbles are especially susceptible to rupture, displacement and rotation, and many of the contacts are tectonic in origin. Selvage of scapolite, diopside, mica and quartz occurs between the meta-granite and marble at this outcrop, but the presence of selvage may be indicative of regional rather than contact metamorphism. Note at this outcrop a convolute, thin band of selvage that extends from the gneiss into marble (Fig. 6). The source of components in the band may lay within the meta-granite. Other features indicative of an igneous origin include aplite veins, cross-cutting relationships and the distribution of carbon and oxygen isotopes at the granite-marble contact.
Marble and granite have been analyzed for oxygen isotopes at the Steer's Head outcrop by Cartwright and Valley (1991). The marbles away from the contact have delta 18O values typical for Adirondack calcite (21-24 ‰). Antwerp gneisses away from the marbles have delta 18O values within the range of Grenville granitic rocks (11-12 ‰). Within a few meters of the contacts, however, delta 18O values increase in the metagranite and decrease in the marble. The result is a sigmoidal shaped delta 18O profile with the inflection points occurring near the contact. This steep gradient is believed to have formed by high temperature, fluid-hosted diffusion of oxygen isotopes from one rock into the other. The question is whether the profile formed during regional or contact metamorphism.
Cartwright and Valley (1991) also observe a change in marble mineralogy toward the contact with the metagranite. Phlogopite content decreases and the diopside content increases, possibly because of a shift to the right in the following reaction:
phlogopite + 3 calcite + 6 quartz = K-feldspar + 3 diopside + H2O + 3 CO2
This reaction buffers XH2O and is favored by increased temperature during contact metamorphism. Another XH2O buffering reaction involves tremolite as follows:
tremolite + 3 calcite + 2 quartz = 5 diopside + H2O + 3 CO2
Tremolite is described as disappearing towards the contact with the Antwerp metagranite, possibly as a result of a shift to the right in this reaction.
A change in the abundance and habit of graphite also is reported in the marble. Coarse (1-2 mm) crystalline flakes of graphite more than 1 m from the contacts give way to graphite free, or finer-grained, disseminated graphite near contact with the metagranite. This change probably resulted from oxidation during intrusion of the granite. Water diffusing from the granite probably caused the breakdown of graphite with the production of methane.
Cartwright and Valley (1991) argue that isotopic exchange occurred during contact metamorphism. Evidence includes the following: (1) Antwerp metagranite would have low porosity, and it is unlikely that enough grain boundary fluid remained in the granite to allow diffusion during regional metamorphism. (2) The systematic changes in marble mineralogy are indicative of contact metamorphism. The observed mineral assemblages also are stable at conditions of regional metamorphism, and little devolatilization would have occurred then. They argue that only during the contact metamorphic event was enough fluid available in the marble.
A larger conclusion drawn from this and other isotope studies at the contacts with meta-igneous rocks is that large volumes of pervasive metamorphic fluids have not infiltrated these localities during the regional metamorphism, or at any time thereafter. The sigmoidal-shaped profiles would not have been preserved had this been the case (Cartwright and Valley, 1991).

STOP 5. Basal, sillimanitic Popple Hill Gneiss.
We are near the base of a thick gneissic unit called the Popple Hill Gneiss and near the contact with Lower Marble. Generally, the gneiss is migmatitic, gray and layered (see stop 6), but here it contains rod-like sillimanite up to 12% by volume (Hudson and others, 1986). Lineations defined by the sillimanite plunge 80 SW. Also present are feldspar porphyrob1asts and lenticular rotated garnets with helicitic textures defined by quartz and sillimanite inclusions (Ambers and Hudson, 1985).
This outcrop has been regarded by some as representing a pelitic protolith whose aluminous composition was appropriate for the growth of sillimanite. The presence of carbonate seams in the gneiss at Devil's Elbow and at Philadelphia village is compatible with an interpretation of a lime-bearing protolith. Stop 5, however, is proposed to be the site of ductile faulting that occurred during or near the peak of metamorphism, with the gneiss having moved northeasterly relative to the marbles in an essentially strike-slip motion (Hudson and others, 1986). In this model the presence of stress is believed to have influenced the growth of sillimanite, perhaps by shifting the following reaction to the right:
2 feldspar + 2 H+ = sillimanite + 5 SiO2(aq) + 2 K+ + H2O (Wintsch and Andrews, 1988)
The mylonites are described as Sr-depleted compared to layered Popple Hill Gneiss from which they are presumed to be derived. A whole-rock Rb-Sr isochron of 1177 ± 40 Ma is younger than ages obtained for the layered gneiss elsewhere and is interpreted as approximating the age of ductile deformation (Hudson and others, 1986). The age also approximates that of AMCG rocks in the Highlands and the Antwerp granite at stop 4; the age falls within the 1170-1130 Ma-interval of high grade metamorphism for the Lowlands as determined by Mezger and others (1991).
This mylonite zone has been extended to connect with the tectonic slide mapped by Foose (1974) near Moss Ridge. Informally called the Hailsboro ductile deformation zone, the mylonite zone may extend across the Lowlands. The Marble City member of Lower Marble lies against Popple Hill Gneiss at this outcrop, and stratigraphically higher members are absent. The gap depicted in our stratigraphic column at the base of Popple Hill Gneiss (Fig. 1) is based on this relationship and on mapping by Foose (1974). Ductile faulting also has disturbed the contact between Popple Hill Gneiss and the units within the Upper Marble in the zinc mines at Balmat. A tectonic slide on the lower limb of the Sylvia Lake syncline places unit 6 in contact with the Popple Hill Gneiss, units 1 through 5 having been excised (Fig. 5) Drill cores penetrating the gneiss generally show blastomylonitic fabrics whereas the overlying carbonate rocks generally are recrystallized "granoblastic mylonitic marbles."

STOP 6. Type locality of the Popple Hill Gneiss.
General:
This outcrop is typical of the migmatitic phase of the gneiss, and sillimanite is much less abundant here than at stop 5. Popple Hill Gneiss lies between two carbonate-bearing units, the Lower Marble of stops 1-4 and the Upper Marble in the Sylvia Lake syncline to the south (stops 7 and 8). The gneiss outcrops in a broad loop along the outer perimeter of the Sylvia Lake syncline and in the Balmat zinc mining district. It outcrops continuously across the Lowlands in a hard-to-farm landscape of bedrock knobs for 70 km from Philadelphia to Colton village.
Because much of the protolith may consist of volcanic ash, Carl (1988) urged that the name be changed from the Major Paragneiss (Engel and Engel, 1953) to the colloquial expression for poplar trees and the hill through which this section of Route 58 was cut (see the road sign). Here is exposed the typical gray, layered, fine grained plagioclase-K-feldspar-quartz-biotite-garnet-sillimanitic gneiss that is strewn with boudins and convolute (ptygmatic) quartzo-feldspathic veins, megacrysts of K-feldspar, layered amphibolites, sill-like bodies of leucogneiss, and other meta-intrusive rocks. Even a 1 cm thick seam of orthoquartzite extends vertically through the outcrop as a fracture-filling of Upper Cambrian Potsdam sandstone.
Geochronology:
A whole rock Rb-Sr isochron of 1296 ± 21 Ma (Grant and others, 1984) and a zircon U-Pb age of 1214 ± 21 Ma (Carl and Sinha, 1992) have been obtained for Popple Hill Gneiss. The discrepancy between the two ages has not been resolved. Both determinations were made on suites of samples from three outcrops that included one common locality here at Popple Hill. The 1.2-1.3 Ga-age of the gneiss must also apply to the Upper Marble whose stratigraphic position above Popple Hill Gneiss is well established by drilling.
The age of Popple Hill Gneiss is particularly important in view of the 1415 ± 6 Ma-age of a leucogneiss dike on Wellesley Island in the St. Lawrence River (McLelland and others, 1988; 1992). Host rocks there must be much older than Grenvillian, perhaps >1500 my, but the extent of their distribution is not known. If these older rocks are widely distributed, then the ca. 1230 Ma-age assigned to Hyde School Gneiss by McLelland and others (1992) would be a revelation. Hyde School Gneiss would be younger than the surrounding rocks and, therefore, intrusive in origin (McLelland and others, 1988; 1992). The previously accepted model would be rendered invalid, i.e. that the Hyde School Gneiss protolith was volcanic tuffs (Carl and VanDiver, 1975), that the bodies represented apical projections of a folded but continuous sheet, and that the gneiss lay near the base of a Lowland stratigraphic sequence (Carl and others, 1990). These recent age determinations of Popple Hill Gneiss, however, do not support an intrusive origin for nearby bodies of Hyde School Gneiss, and the argument regarding an intrusive origin has shifted to other grounds.
A 40 m thick body of metagranodiorite that we regard as intrusive into Popple Hill Gneiss occurs at the northern end of this outcrop. It has given a whole rock Rb-Sr isochron age of 1147 ± 35 Ma (Grant and others, 1984). This age indicates that the intrusion was contemporaneous with movement along the Hailsboro ductile deformation zone (stop 5) and with intrusion of the AMCG suite in the Highlands. Evidence for intrusive origin includes the young age, the presence of K-feldspar megacrysts (phenocrysts?), amphibolite that occurs as angular blocks (xenoliths?) rather than layers, and a more mafic composition than Popple Hill Gneiss. Contacts with the gneiss have been tectonized so that cross cutting relationships are not observed, or the body may be a sill. The intrusion is cut by numerous quartzo-feldspathic veins.
Migmatite and the Availability of Fluid during Metamorphism:
The belt of Popple Hill Gneiss crosses the isotherms of regional metamorphism that signify a transition from upper amphibolite to the granulite facies, from ca. 6400C in the SW to 7400C in the NE (Seal, 1986). Popple Hill Gneiss, thus, has the potential for study of mineral and chemical change as well as the availability of fluids during prograde metamorphism. The unit has been thoroughly sampled (Engel and Engel, 1953; 1958; Stoddard, 1980; Seal, 1986; Edwards and Essene, 1988; Ehrhard, 1986; Powers and Bohlen, 1985; Hoffman, 1982; see summary in Valley and others, 1990).
Quantitative estimates of the values for water activity are based on the equilibria of reactions that include:
(1) annite (biotite with Fe in octahedral sites) + sillimanite + quartz = almandine + sanidine + H2O, and
(2) muscovite + quartz = sanidine + sillimanite + H2O.
Calculated values of water activity range from 0.1 to 0.5 (Valley and others, 1990). Values are uniformly low, although not as low as in higher grade rocks in the Highlands. Values decrease from Gouverneur to higher grade metamorphic rocks to the NE near Colton.
Valley and others (1990) note that the gneiss is the largest migmatite unit in the Adirondack Mountains. The type locality here is replete with convolute quartzo-feldspathic leucosomes, some parallel to the foliation and others cross-cutting. The low values of water activity recorded for the gneiss can be used to argue that the leucosomes had formed by partial melting. Water produced during dehydration of mica and other minerals would be partitioned into the incipient melts, and the unmelted residue would be further dehydrated and made harder to melt. In support of this idea, Valley and others (1990) point to the local variability in water activity throughout the unit, suggesting that fluid compositions may have been internally buffered by solids or by melt. Buffering is consistent with the presence of migmatite and with partial melting.
Leucosomes within the gneiss, thus, may be locally derived and not introduced. Carl (1988) proposed an in situ origin on the basis of (1) the lack of leucosomes in either Lower or Upper Marble formation, (2) the presence of Ba-, Sr-, and Rb-rich leucosomes in Popple Hill Gneiss outcrops whose mesosome is enriched in Ba, Sr and Rb, (3) the presence of heavy REE-depleted leucosomes where mesosome is similarly depleted, and (4) the dominance of K-feldspar leucosomes in layered gneiss versus plagioclase leucosomes in the amphibolite layers. An origin by metamorphic differentiation was proposed for those leucosomes with exceptionally high K2O content that lacked minimum melt composition (Carl, 1988).
The studies of Valley and others (1990) are interpreted to rule out the passage of large amounts of fluids through Adirondack rocks during high grade metamorphism. On a local level, however, fluid migration into partial melts remains a possibility, and Popple Hill Gneiss may be unusual in that it retained much of the melt as leucosome (up to 25% at some outcrops). Higher grade gneisses in the Adirondack Highlands may have lost much of their melt fraction to consist chiefly of restite.
Minor folds are abundant in this outcrop. Many display overturned "s" asymmetries as viewed to the NE, suggesting that a major syncline lies to the east. In fact, the Sylvia Lake syncline is located east of this outcrop and may have influenced the orientation of minor folds. A number of folds, however, display "Z" asymmetries. Do these fold s suggest a separate or later fold event? Not necessarily. Note that many folded veins exhibit crosscutting relationships, and recall that fold asymmetries depend upon the orientation of the veins prior to folding. Thus, it is possible to have "S" and "Z" folds in the same outcrop that are coeval.

STOP 7. Stromatolites in Upper Marble, units 4 and 5.
NO HAMMERS AND NO SAMPLES, NOW AND FOREVERMORE (PLEASE).
Unit 4 of the Upper Marble (Fig. 7) in the Sylvia Lake syncline contains the first known biological remains described from the Adirondack mountains (Isachsen and Landing, 1983). This stromatolite-bearing rock is exposed in the woods above the roadcut. It consists of an alternating sequence of white dolomite, serpentinous-talcose diopside rock, and quartz lenses that may represent a chert-bearing, silty, peritidal dolostone intercalated between pure dolostones. Diopside formed by reactions between quartz and dolomite, and the rims of serpentine and talc owe their origin to retrograde metamorphism. Because the sequence is upside down, unit 5 underlies unit 4 in the roadcut. Unit 5 is a white to grayish, coarse-grained dolomite that contains sparse lenses of quartz and talcose diopside. Occasionally the dolomite is fetid.
The term stromatolite is applied to laminated carbonate sediment that occurs as bulbous heads or stacks. The laminations follow the outline of the structure and may be terminated at the edge of individual heads. Individual laminae may be thicker on the top and drape over the edge of the head to make a steep angle. Stromatolites are well displayed at this outcrop, and perhaps their late recognition can be attributed to an overturned position. The delay could also be attributed to frayed wiring in the twilight zone between the eye and brain of numerous observers, including your field trip guides who did not expect to see what they saw.
Stromatolites in unit 4 are domal SH-V stromatolites that occur as simple domes up to 12 cm high and 40 cm wide (Isachsen and Landing, 1983). They are composed of broad, convex laminae that consist of dolomite and iron-poor diopside (cream-colored rather than green), and they lack structural detail in thin section. The preservation of stromatolites may be due in part to their composition. Some are incompletely preserved with laminated quartz-diopside rock making up the preserved part. Silica replacement of algal structures during diagenesis can account for the preservation, whereas the unreplaced parts would recrystallize during metamorphism to coarse dolomitic marble. Fully replaced quartz-diopside mounds would form a rigid but minor structural buttress during deformation.
This outcrop lies on the upper, overturned limb of the Sylvia Lake isoclinal syncline. The stromatolites indicate that the upper limb is inverted and that this NNE-plunging complex fold is indeed a syncline as geologists of St. Joe Minerals (now ZCA) had proposed many years ago. Stromatolites have been recognized in units 4 and 11 of Upper Marble in recent years, and deLorraine has photographed domical stromatolites and finely laminated, possibly algal mat structures at the 2500 ft. level in the Balmat mine.

STOP 8. Units 14 and 15 of the Upper Marble fm
This newly completed roadcut (late 1992) in units 14 and 15 of the Upper Marble formation (Fig. 7) represents a rebuilding of Route 812 that followed collapse of the old road into an underground mine.
This roadcut occurs in the core of the Sylvia Lake syncline in the Upper Marble formation at Balmat. Subunits of unit 14 comprise the northern part of the cut, whereas the brownish and green rocks in the south part belong to unit 15, a phlogopite/tremolitic calcitic marble (Fig. 7). Unit 14 is composed of a variety of rock types including quartz-calcite marble (the "quartz-mesh limestone" of Buddington), thinly layered quartz-diopside rock, and serpentinous dolomite and calcitic marbles, to name a few. At the southern hinge of the Sylvia Lake syncline near Balmat, minor fold plunges are northerly or slightly west of north. Since the sides of the roadcut here are parallel to the plunges of minor folds, it is difficult to see many folds on the outcrop faces. On the southern end of the cut it is possible to see folds developed in unit 15. Minor folds associated with the Sylvia Lake syncline deform the schistosity in units 14 and 15 and, hence, the minor and major folds are interpreted as second phase isoclines. Down plunge (in the mines) the fold axes swing to the NE. At the other end of the syncline at Edwards, fold axes plunge to the NW. The overall geometry of the fold, thus, is lobate, and the Sylvia Lake syncline is interpreted as a sheath fold (Fig. 8).

Flat solution valley
Flat solution valley that surrounds the Hyde School body of Hyde School Gneiss which is in view straight ahead.

STOP 9. Amphibolite layering in the Hyde School body
Amphibolite layering in the Hyde School body of Hyde School Gneiss (Fig. 9).
Layering: Large and Small Scale
Hyde School Gneiss with numerous, thin biotitic-amphibolite layers is exposed in the smooth bedrock knobs overlooking a small pasture. We are located at the southern end of an F2 fold that parallels the Hyde School antiform (see map of Brown, 1988). The orientation of numerous minor folds in the amphibolite layers can be related to the Hyde School antiform, interpreted here as a major, second phase sheath fold. The antiform deforms an earlier fabric, including NW-SE trending lineations and rootless isoclines that may be related to Tewksbury's early shear fabric. Nearby are isoclinally folded amphibolite layers whose axes trend NW-SE, perhaps having been rotated into parallelism with the direction of early phase, NW -directed tectonic transport.
We are near the contact between two pink alaskite units of Brown (1988), one (aa) distinguished by thin parallel layers of biotitic amphibolite, and the other (a1) a massive unit with fewer layers (Fig. 9). Another mappable unit (pgd) consists of gneisses ranging in composition from biotite granite, trondhjemite, quartz monzonite, granodiorite to quartz diorite. All are foliated and contain amphibolite layers. Detailed mapping of the large-scale layering enabled Brown to interpret complex refold patterns, and we will discuss his work in the shade of a small tree.
Hyde School Gneiss, thus, differs from granitoid plutons of the Adirondack Lowlands in being compositionally zoned on a grand scale. Brown (1988) wrote that "the alaskite, granite, and diorite gneisses of the antiforms are a parallel-layered sequence that, despite abundant evidence of internal mobility and local melting, have not intruded each other or broken out of their elliptical structural shells as a melt." In contrast, the younger Lowland granitoid rocks show abundant evidence for intrusive origin. The Rockport granite and Gananoque syenite occur as dikes, sills and apophyses within metasedimentary rocks that outcrop along the St. Lawrence River. Even the oldest rock recorded so far, a 1415 Ma-old leucogneiss on Wellesley Island, is described as a dike within calc-silicate and tourmalinite layers (McLelland and others, 1988).
One objective of this stop is to observe the scale of the amphibolite layering, folding, and boudinage. These features are characteristic of Hyde School Gneiss. Note the absence of other lithologies or inclusions. No other granitoid bodies in the Lowlands exhibit layering like this, and most, if not all, have xenolithic inclusions of country rock attesting to their igneous provenance. Hyde School Gneiss is unique in being restricted to one stratigraphic horizon, containing layer-parallel amphibolites, and in the absence of xenolithic inclusions of the adjacent host gneisses. Feldspathic quartzites, calc-silicate and garnet-sillimanite gneiss occur within bodies of Hyde School Gneiss but, like the amphibolites, they also occur as parallel layers generally < 1 m thick.
Thus, Hyde School Gneiss consists of conformable lithologic layers on a large and small scale. Does the layering result from tectonism during intrusion, tectonism after intrusion, or is it a primary feature related to the deformation of ash and lava beds? Do the amphibolites represent basaltic dikes that were realigned prior to complete consolidation of the granitoid magma, so that igneous breccias and textures are preserved? Do the amphibolites represent dikes that were realigned strictly by solid state deformation? Do they represent slab-like sections of amphibolite wall rock that had been loosened during shearing and permissive intrusion of the granitoid magma? All scenarios have been proposed in one form or another.
A less complicated approach for the origin of Hyde School Gneiss begins with a layered complex of alternating ash-flow tuffs and minor metasediments, capped in some cases by outpourings of more fluid lavas and ash of trondhjemic and dioritic composition. Solid state deformation, with localized partial melting in low pressure sites, and late stage pegmatite intrusion, would account for features cited by others as evidence for intrusive origin. If the amphibolite layers were once basaltic dikes that had intruded the complex, then transposition to parallelism with the surrounding rocks had to occur prior to the 1170-1130 Ma period of high grade metamorphism in the Lowlands, because the amphibolite bodies were deformed after they had acquired the layered form. If the amphibolite layers represent original lithologies, e.g. protoliths of iron-rich, calcareous shales or basaltic ash, then deformation could have occurred simultaneously with high grade metamorphism.
High Temperatures and Contact Metamorphism?
The most compelling evidence for intrusive origin of Hyde School Gneiss cited by McLelland and others (1992) is the presence of perthite within the gneiss and the presence of a high grade mineral assemblage (garnet, sillimanite and spinel) in gneisses that surround Hyde School Gneiss. Perthite may form from exsolution of hypersolvus feldspar, the existence of which implies temperatures higher than those proposed for Lowland metamorphism.
It is interesting to note that the high grade mineral assemblage might have been used as evidence for higher temperatures of regional metamorphism had the assembly been found elsewhere than adjacent to Hyde School Gneiss. A search is underway to determine if the assemblage occurs in pelitic rocks elsewhere in the Lowlands. Given the paucity of Lowland pelitic rocks, and the remarkable selectivity that Hyde School Gneiss magma presumably has shown in intruding only pelitic horizons, we think it appropriate that the upper ranges of temperatures proposed for Lowland metamorphism be reconsidered. Also needed are U-Pb ages of garnet from the sillimanitic gneisses adjacent to Hyde School Gneiss. If the ages are >1200 my (similar to the age of the gneiss) then contact metamorphism is a possible cause. If the ages are <1200 my, then regional metamorphism is likely.
The proposal that stratigraphic principles cannot be applied in the Lowlands goes hand in glove with the model of intrusive origin for Hyde School Gneiss. Pelitic rocks can be conveniently distributed where needed as a host for granite intrusions. One may dismiss the present view of Popple Hill Gneiss as a lithologic/stratigraphic unit confined to the south-central Lowlands. It may be presumed to be distributed elsewhere, intruded by Hyde School Gneiss magma and partially melted so that the residue is left as a garnet-sillimanite gneiss that surrounds Hyde School Gneiss (McLelland and others, 1992).
On the other hand, we suggest that Hyde School Gneiss may represent a layered volcanic complex overlain by the lowest member of Lower Marble formation, whose pelitic composition was favorable for growth of garnet, sillimanite and spinel during the period of high grade regional metamorphism from 1170 to 1130 Ma.
A Stratigraphic View of Hyde School Gneiss:
The picture that emerges from detailed field mapping of members of Lower Marble formation is that the bodies of Hyde School Gneiss occur at the same stratigraphic horizon across the Lowlands. Each body is associated with the Black Lake member of the Lower Marble Formation. It is difficult to imagine how independent intrusions could acquire such similar surroundings unless the carbonate cover was deposited unconformably over each dome as proposed by Wiener and others (1984). Previous references to the gneiss appearing at various horizons across the Lowlands are incorrect. The California body of Hyde School Gneiss was cited as being in contact with Popple Hill Gneiss, with the inference being that the contact was intrusive in origin (Buddington, 1929; McLelland and others, 1992). However, the marble is exposed on the surface, and Zinc Corporation drill core shows that the Black Lake member of Lower Marble occurs between Hyde School Gneiss and Popple Hill Gneiss.
Xenoliths of adjacent metasedimentary rocks occur in Hermon-type and in most other meta-intrusive rocks throughout the Lowlands, particularly at the margins of a body. Diligent search has produced few xenolithic candidates in Hyde School Gneiss other than amphibolite. Cushing (1916) observed as much when he wrote of inclusions in Hyde School Gneiss as consisting of amphibolite "no matter what the nature of the bordering Grenville rock is" (p. 18).
The conformable amphibolite layers in Hyde School Gneiss have been interpreted as slabs that were stoped and separated along foliation planes by incoming magma (Levy and others, 1993). This process requires the fortuitous convergence of the following unrelated factors: (1) The necessary presence of vast quantities of amphibolitic material immediately below the Black Lake member of Lower Marble. (2) The necessary requirement that the batholith intrude but one stratigraphic horizon and that it stoped only the amphibolite layers. Apophyses, dikes and sills of Hyde School Gneiss are non-existent in the surrounding metasedimentary rocks. (3) The requirement that the magma be extremely fluid in order to incorporate slabs that vary in thickness from 1 to 60 cm or more. Many so-called slabs have uniform thicknesses for tens of meters. (4) The requirement that magma of stock-like to batholithic dimensions was confined to one or several substrata of appropriate pelitic composition that, in turn, could be subjected to contact metamorphism to produce the ever-present garnet-sillimanite gneiss.

STOP 10. The Pope Mills gabbro (Fig. 9)
Do not climb the outcrop to the right (E) onto the lawn of the trailer.
The purpose of this brief stop is to examine a folded and metamorphosed mafic intrusion within the Lower Marble formation as a prelude to examination of the Fish Creek body of Hyde School Gneiss. The Pope Mills gabbro was interpreted by Buddington (1934) as a relatively large mass of "pyroxenic amphibolite" that had been sheared prior to intrusion of syenitic magma. The intrusion of syenite into foliation planes, with the help of mineralizers, was believed responsible for the "migmatitic character" of the body, particularly the K-feldspar megacrysts and augen that are strikingly displayed at outcrops further to the south. The body was isoclinally folded and overturned towards the northwest with the dip of foliation varying from 55 to 70° SE (Buddington, 1934).
Xenoliths of banded, greenish calc-silicate from the Black Lake member of Lower Marble occur within the metagabbro. At least three phases of the gabbro are recognized: (l) sub rounded to angular and block-like forms of fine grained gabbro that are surrounded by (2) a slightly coarser grained gabbro matrix. Also present, but not at this outcrop, is (3) a biotite and K-feldspar megacrystic gabbro that Buddington regarded as a mixed rock. Examine the weathered horizontal surface on the west side of the road, and note the calc-silicate xenoliths that form a tectonically re-aligned intrusion breccia. Also note the deformed, fine grained gabbro ellipsoids whose long axes trend N 75 E.
Representative chemical analyses of the three gabbroic phases are given in Table 1. The coarser grained matrix (sample 223) is richer in total Fe, TiO2 and P2O5 than the finer grained phase (sample 222). We tentatively regard the finer grained gabbro as autoliths, and the coarser grained matrix as a later, more differentiated, iron-rich phase of the same magma.

STOP 11. SW margin of Fish Creek body (Fig. 9)
Park on Route 58 south of the Bishop road (right) and walk northward to the outcrop.
Hyde School Gneiss is exposed in the hinge/axial region of the Fish Creek anticline. Nowhere could a more challenging and complex outcrop be found, because these cuts expose highly deformed alaskitic and trondhjemitic gneisses with parallel layered amphibolites in the core of a regional "anticline that looks like a syncline" (i.e. a sheath fold) . Amphibolite layers may have undergone an early deformation that resulted in "chocolate-tablet" style boudinage before being refolded in the hinge of the Fish Creek anticline. Pegmatites with feldspar, green clinopyroxene and titanite assemblages intrude the suite of leucogneisses and also may appear at or near the contact with the overlying Black Lake member. Did the pegmatitic fluids derive some constituents from the carbonates up section? Mafic dikes, probably offshoots from the Pope Mills metagabbro, are present and superficially resemble the amphibolites. Other intrusive rocks also may be present in these outcrops.
The following scenario for the Fish Creek body is proposed by deLorraine: Begin with a "normal" sequence of Hyde School Gneiss, the trondhjemite phase in contact with overlying Black Lake metasediments that are exposed at the south end of the outcrop at Bishop road. Rocks are subjected to high grade metamorphism and deformation with temperatures at the higher end of those reported in the literature. The earliest phase of deformation produced chocolate-tablet boudinage in the conformable amphibolite layers, accompanied by partial melting in the neck zones of boudins. Pegmatites are intruded, possibly channeled along the interface between Hyde School Gneiss and the Black Lake member. Offshoots of the Pope Mills metagabbro are intruded, and one wonders about contributions to the local heat budget that may have facilitated partial melting in Hyde School Gneiss.
Phase two isoclinal sheath folding then affected the region, producing the NE-SW regional grain. The second phase, sheath fold hinge in the SW end of the Fish Creek anticline resembles an "anticline that behaved like a syncline" because of the northerly plunges of a profusion of minor tight to isoclinal folds (see proposed sketch of the structure of the Fish Creek body, Fig. 10). "M and W" minor folds in the hinge of the anticline were superimposed on amphibolite layers that previously had undergone chocolate-tablet boudinage. Partial melting would be enhanced in the core of the Fish Creek anticline because it would be a low pressure site. Magmatic heat contributions from the sill and dikes offshoots of the Pope Mills metagabbro also may have facilitated partial melting. So-called "intrusion breccias," thus, are best interpreted in a regional framework as broken, boudinaged fragments of conformable amphibolite layers which have been refolded and deformed in the solid state by "M and W" folds. The best place to verify that the amphibolite layers are not randomly or chaotically distributed is to observe them from the top of the outcrop on the west side of the road. Look to the north down the plunges of minor folds.

STOP 12. Mafic layers in the Fish Creek body
Mafic layers in the Fish Creek body of Hyde School Gneiss, pasture of the Yoder farm (Fig. 9).
One purpose of this stop is to distinguish late dikes that may be related to the Pope Mills metagabbro (stop 10) from amphibolite layers of the Fish Creek body of Hyde School Gneiss. Metagabbro dikes are shown to post-date the foliated amphibolite layers and an early phase of isoclinal folding. Although the dikes have been deformed and metamorphosed (as is the case with the Pope Mills gabbro), they are clearly younger than the amphibolite layers.
The dikes and amphibolite layers have been regarded as coeval. Cross-cutting relationships as observed here have been used as evidence that all mafic layers had formed as dikes which, in turn, had been transposed shortly after their emplacement within Hyde School Gneiss magma (Mclelland and others, 1992). Phenocrystic plagioclase and coarse subophitic orthopyroxene have been used as evidence for an intrusive origin (Levy and others, 1993), but we believe it is the dikes that have been described rather than true amphibolite layers. The dikes have abundant orthopyroxene in various stages of alteration to hornblende. The amphibolite layers are chiefly amphibolite and biotite with little pyroxene.
The Fish Creek body was mapped by Dietrich (1954; 1957) who agreed with Buddington that the Hyde School Gneiss was intrusive in origin (he later changed his mind to an origin as in situ anatectic magma; Dietrich, 1963). The disrupted amphibolite layers were described as xenoliths throughout the 1957 report. In addition to the amphibolite layers, Dietrich recognized 18 tabular "amphibolitized melanocratic dikes," ranging from nearly 2 ft. to a few inches in width (see photos p. 57-58 in Dietrich, 1957).
We will examine several gabbroic dikes exposed in the pastures on both sides of Bishop road. One of the dikes cuts several amphibolite layers, including one that has been isoclinally folded. The dike has been realigned to near parallelism with the amphibolite layers at one end of the outcrop. A 1 m thick dike elsewhere in the pasture cuts several amphibolite layers at an acute angle. One layer can be traced into the dike where it reappears as ruptured fragments that are true xenoliths. Clearly the amphibolite had acquired its foliation and layered form prior to intrusion of the dikes.
We have observed these dikes only in the Fish Creek and Stalbird bodies of Hyde School Gneiss. They are particularly abundant in the Fish Creek body, perhaps because of the presence of the Pope Mills gabbro.
We compare the chemistry of (1) dikes in the Fish Creek body, (2) Hyde School Gneiss amphibolite layers, and (3) Pope Mills gabbro (Table 1). In general, Hyde School Gneiss amphibolites contain more MgO, Cr and Ni than the Pope Mills gabbro. Advocates of a meta-igneous origin for the amphibolite layers may regard enrichment in these elements as indicative of a lack of olivine fractionation in their source. We have used plots of MgO vs CaO (Fig. 11A) and FeO-MgO ratios vs Cr (Fig. 11B) to distinguish Hyde School Gneiss amphibolite layers from Pope Mills gabbro. Fish Creek dikes plot with the gabbro.
Fish Creek dikes resemble the Pope Mills gabbro in a tendency toward iron enrichment. Both groups show increasing Zr (and TiO2 and P2O5) content and decreasing Cr and Ni (and CaO) content with increasing Fe-Mg ratio (Fig. 11C). In contrast, the amphibolite layers generally have lower Fe-Mg ratios and show relatively erratic changes in abundances of these elements with increasing iron content (Fig. 11D). We tentatively regard the dikes as fractionated, iron-enriched derivatives of the Pope Mills gabbro. More samples are needed.

STOP 13. Tourmalinites and quartzites
Tourmalinites and quartzites with a thinly layered appearance.
Exposed here are fine grained, gray to deep maroon, tourmaline-bearing metasedimentary rocks that include quartz-feldspar-mica-diopside gneisses, calc-silicates and quartzites. Note the inclined, 1 m thick layer of dark, glassy quartzite that contains tiny, vitreous grains of dark tourmaline. These grains could be overlooked or mistaken for biotite. We correlate the rocks with tourmaline-bearing gneisses and quartzites of unit "qmt" (Fig. 1) in the Beaver Creek area (Brown, 1989). Lithologically similar rocks have been intruded by the Rockport pluton in the Thousands Islands area, suggesting that "qmt" or its equivalents may be of widespread occurrence in southeastern Ontario.
Tourmalinite is abundant in the Lower Marble and may have crystallized from boron-rich basinal brines during diagenesis and metamorphism (Brown and Ayuso, 1985). Feldspathic quartzites and quartz-feldspar-mica granofels contain layers with up to 50% tourmaline whose composition is dravite-uvite with 0.85 to 4.25 wt.% Na2O, 0.39 to 4.04% CaO, and up to 13 .67% MgO (which is near end-member dravite composition). Li-rich compositions have not been found.
Tourmaline also occurs in sheet-like bodies of metagranite that intrude "qmt," but the tourmaline is compositionally distinct from that in the metasedimentary rocks (Brown and Ayuso, 1985). Ratios of FeO-(FeO+MgO) range from 0.55 to 0.75 in granites and pegmatites, compared to ratios of 0.15 to 0.58 for tourmalines in quartzites. Previous workers believed that the tourmaline in the metasedimentary rocks had originated from the granitic intrusions, but the reverse may be true. Intrusive rocks may have picked up (and compositionally modified?) the tourmaline from the metasedimentary rocks, as is suggested by the distribution of the tourmaline-bearing intrusions. Abundant tourmaline occurs in the metagranite that intrudes "qmt" rocks near Huckleberry Mountain (Richville quadrangle), whereas tourmaline is less common in granites that have intruded other rock units.
Some rock types within the unit "qmt" are intensely limonite-stained by the weathering of pyritic zones. Pyrite mining was carried out as a source of sulphur and sulphuric acid for the paper industry at Pyrites, Stellaville and elsewhere in northern New York in the late 19th and early 20th centuries.

STOP 14. Hermon-type granitoid gneiss of the Gray's School body.
At least two textural types of granitoid meta-intrusive rocks were mapped in the Lowlands at the turn of the century, a fine-grained, so-called "equigranular" gneiss of the Alexandria-type that included the Hyde School Gneiss, and a coarser grained, K-feldspar megacrystic gneiss called the Hermon-type (Cushing and others, 1910). The mapping of numerous small and isolated granitic bodies throughout the Lowlands eventually led to the adoption of local names and to the abandonment of the term "Alexandria-type" But the name Hermon-type is still applied to relatively small, sheet-like and irregularly shaped, K-feldspar megacrystic plutons that are scattered throughout the Lowlands.
Hermon gneisses are generally reddish, medium to coarse grained feldspar-biotite-hornblende-quartz-titanite gneisses of syenitic to granitic composition (note the paucity of quartz at this outcrop). They contain large K-feldspar megacrysts that occasionally are oriented transverse to foliation. This coarse grained rock may give way along strike to become a fine grained equigranular gneiss. Pervasive grain size reduction may be responsible, and K-feldspar augen, flaser structure and quartz ribbons are often observed in thin section in association with a mosaic textured groundmass.
Igneous textures have survived the metamorphism and ductile deformation. Concentrically zoned megacrysts of K-feldspar are observed in thin section to contain zones of patch or speckled or "fire flake" perthite that alternate with wider zones or bands of nonperthitic feldspar. Plagioclase grains and biotite flakes lie against the perthite zones and protrude outwardly from them. We interpret these grains to be Frasel or epitatic inclusions that originally adhered to the face of a K-feldspar crystal that crystallized from a melt The rims of fine grained pink feldspar that surround the phenocrysts were produced by ductile deformation.
Hermon gneisses generally occur as intrusions within the Lower and Upper marbles and the Popple Hill Gneiss. Conformity with the host rock, due in some cases to tectonism, has caused some to be mapped as lithologic units. They generally occur as sills and less often as dikes or apophyses. Xenoliths of amphibolite are common.
Each intrusive body of Hermon gneiss is characterized by a limited range in major element content. For example, samples from the Gray's School body (including this outcrop) are uniformly syenitic, low in SiO2 and rich in MgO (Fig. 12; see sample 101A in Table 2). Gneisses near Hermon village are of intermediate SiO2 content (sample 178), and samples of high SiO2 and low MgO content (sample 124) are characteristic of the Mott Creek body. We believe that these rocks represent a common intrusive series.
We compare Hermon gneisses with another Lowland metagranite, the "equigranular" Rockport gneiss which outcrops in the islands and along the shore of the St Lawrence River. Formerly called the Alexandria Bay Formation, this rock was cited by Wiener and others (1984) as equivalent to Hyde School Gneiss and, thus, was made to represent the basal stratigraphic unit in the NW Adirondacks. Rockport gneisses are quartz-feldspar-biotitic gneisses with less hornblende and titanite than Hermon gneisses. Fluorite is a notable accessory phase, as is tourmaline where tourmaline-bearing host rocks have been intruded (Brown and Ayuso, 1985). Rockport gneisses clearly show an intrusive origin as dikes, sills and stock-like masses. Geochemical and field differences suggest that they represent a more highly differentiated and less viscous magma than Hermon-type magma. Hermon gneisses show a tendency toward calc-alkaline character (Fig. 13A, B) that contrasts with a pronounced alkaline character for Rockport gneisses . Both gneissic groups plot chiefly in the field of "volcanic arc" granites on an Rb vs Y + Nb tectonic discrimination diagram (Fig. 13C) Plots of both gneisses are widely scattered among I, S and A-type granites (Fig. 13D). In contrast, granitoid rocks of the AMCG series in the Adirondack Highlands (Figs. 13C, D) plot chiefly as alkaline, A-type "within plate" intrusive rocks (McLelland, 1986; McLelland and Whitney, 1990; Daly and McLelland, 1991).

A2: THE POTSDAM-GRENVILLE CONTACT REVISITED (I)
JOHN BURSNALL
Canton, NY 13617
BILL ELBERTY
Department of Geography
The purpose of this field trip is to examine the relationships at the boundary between Proterozoic Grenville gneisses within the Adirondack Lowlands and overlying arenaceous rocks, presumed to belong to the Potsdam Sandstone of Upper Cambrian (?) age. It is the first of two that will explore the diverse mineralogy, lithology and structure of a number of arenaceous outcrops in the Canton-DeKalb-Gouverneur area and will provide an overview of the compositional and structural characteristics of some of these problematic rocks.
(Please note that trips A2 and B2 can be taken together, as a single long day sequence, or independently. This fieldguide includes a repeat in Trip B2 of Trip A2 stops 7 and 8 to conveniently provide a shorter day's review.)
The Potsdam-Grenville contact in the St. Lawrence valley represents a hiatus of some 500 Ma. Mineral assemblages within the Grenville gneisses indicate that perhaps 25 km of material was eroded prior to the deposition of the transgressive Cambro-Ordovician sequence, over an undulating Precambrian erosion surface. Many of the isolated, predominantly sandstone, bodies within the Grenville gneiss terrane of the Adirondack Lowlands can be confidently interpreted as outliers of Potsdam Sandstone. The focus of this field trip, however, is to question the affinity of those whose relationship to the Cambro-Ordovician sequence is equivocal. Such enclaves vary in composition from matrix supported breccias to equigranular orthoquartzites and their depositional environment has been variously interpreted as: pre-Potsdam solution pocket infills (related to a karst topography on a Grenville marble surface); fault related debris slides; fault breccias; and fault scarp talus accumulations. Some are seemingly crudely interlayered with the gneisses and are locally foliated. Rare sandstone/breccia dykes within the gneisses may be of significance in understanding the origin of these enigmatic, apparently sedimentary, clastic rocks.
This fieldtrip commences at exposures close to the St. Lawrence Seaway between Ogdensburg and Alexandria Bay - including the text book exposures of the Potsdam - Grenville unconformity east of Alexandria Bay (Fig. 1). This will take from 25 to 40 mins., depending on traffic conditions. We then head south towards the village of Theresa and start our investigation of the arenaceous enclaves within the gneiss terrane. In the process we will visit some of the classic outcrops of the St. Lawrence Valley and Adirondack Lowlands where arenaceous rocks in contact with demonstrable Precambrian are of uncertain age and origin. Some of these rocks are seemingly deformed along with late Grenville deformation (that is, exhibiting a qualitative strain level not seen in the Potsdam Sandstone; Trip B2) whereas others exhibit intrusive relationships to the gneisses (Trips A2 and B2), or lie structurally beneath them (Trips A2 and B2). The origin of these enigmatic relationships have variously been proposed as :
1) outliers of Potsdam Sandstone;
2) pre-Potsdam, post-Grenville in age;
3) Grenville in age, in that they have enjoyed at least the later stages of Grenvillian deformation.
It is likely that all of these relationships are represented on this fieldtrip - but the question we ask, since most relationships are at least superficially ambiguous, is - "how can we discriminate between them". We hope for fruitful discussion on outcrop that will lead towards a better understanding of the status of these "enclaves". Some of these outcrops have long been recognized as contentious and constitute a longstanding problem. It would be nice to move closer to solving it!

A2: THE POTSDAM-GRENVILLE CONTACT REVISITED (I)

STOP 1. Deformation in middle Theresa Formation
Gentle northeasterly-trending folds of Potsdam Sandstone and Theresa Formation are relatively common to the south and west of Theresa (Barber 1977). The examples in this road section are similar in geometry to those observed in that area. They are significant to this field trip in that they clearly demonstrate significant post Potsdam regional deformation. Folds in the Potsdam Sandstone north of Theresa will be seen (Stop 4, Figure 2, this trip) are considered likely to be the same age. A minor fault will be seen in the central part of this section.
Continue on Route 12 passing through some magnificent roadcuts of Theresa Formation and Potsdam sandstone that are featured in Trips A3 (Erickson) and B2 (Selleck). Continue past the village of Chippewa Bay, across marshy ground on the southern shore of the St. Lawrence.

Very large outcrops on both sides of road
Very large outcrops on both sides of road with an obvious contact at their eastern end.

STOP 2. The Potsdam Grenville unconformity at Alex Bay.
PLEASE WATCH FOR FAST MOVING TRAFFIC
This classic example of an unconformity shows typical, regularly layered, lowermost Potsdam Sandstone lying on deformed Grenville gneisses. Some slip has occurred along the contact resulting in small-scale buckling of a subvertical foliation within the gneisses on the north side of the road.
The nature of the unconformable relationship and the character of the Potsdam Sandstone immediately above the contact at this stop will provide a basis for discussion at subsequent outcrops and is typical of the basal Potsdam in this area, although no trace fossils have been observed (Selleck, this volume). Note the rare conglomeratic horizons and the well-defined bedding.

Up a sharp rise onto the plateau
Up a sharp rise onto the plateau underlain by the flat-lying Paleozoic sequence which is characteristic of this section of the St. Lawrence Valley.

Note exposures of gneisses in fields to the right.
The wooded higher ground ahead on both sides of Route 37 are underlain by sandstones.

An excellent example of the unconformity at their base

Note gneisses to the north, and escarpment ahead
Drive across a bridge, noting gneisses to the north, and head up the escarpment ahead.

STOP 3. Soft-sediment deformation close to the Precambrian erosion surface.
Unusual columnar structures within the sandstones of this region have been described from a number of localities (Van Diver, 1976; Dietrich, 1953). They measure from a few inches in diameter to 10 feet or more. Characteristically they possess a cylindrical or cone-like structure with a narrow structureless border zone that cross-cuts the bedding in the surrounding rocks. Concentric sub-vertical layering paralleling the margin may occur and, in the larger examples, the interior may be brecciated. This internal breccia may be comprised of laminated sandstone fragments set in a homogeneous sandstone matrix. This particular example, which must occur close to the Precambrian surface beneath well demonstrates these relationships. Abrupt truncation of bedding within the surrounding sandstone will be seen at the eastern margin of the structure and a brecciated central zone may be observed; individual clasts are typically poorly defined The origin of this and similar structures is not fully understood, but is thought most likely related to localized collapse of semi-consolidated sediment - that is the downward movement of a column of sand. A possible cause is settling or collapse of cavities in the underlying rocks - an hypothesis resulting from the observation that the location of these features is within sandstones seemingly overlying marbles within the underlying Proterozoic sequence. Subsequent stops will support this notion. The homogeneous sandstone matrix surrounding breccia fragments suggests a lack of grain coherence (and resulting aggregate fluidity) that may have been initiated by high pore fluid pressures. The details and mechanics of such an environment will be discussed at this and subsequent outcrops. Similar structures are common elsewhere within the Potsdam Sandstone of this region and in equivalent rocks of the Ottawa basin to the north (Grabs personal communication 1979).

STOP 4: Folds within the "Potsdam Sandstone" (Figure 2)
Outcrop of deformed "Potsdam Sandstone" on the east side of the road across a disused railroad line.
PLEASE NOTE THE POISON IVY AT THIS STOP
Further evidence of gentle large-scale folding within arenaceous rocks of presumed Potsdam age is exhibited here (Figure 2). These exposures of sandstone are typical for the area. Bedding is pronounced, with the rock taking on a 'flaggy' appearance locally. Hematite staining may accent layering, including cross-bedding, but also is apparently not controlled be internal structure in places cross-cutting the sedimentary structures. Such 'liesegang banding' is quite common throughout the Potsdam Sandstone in this region. Evidence for soft sediment deformation is present and a small monocline behind a pine tree in the center of the face could be a product of differential settling.
Barber and Bursnall (1978) described the folding in this outcrop as follows: "Bedding is folded in a manner typical of the lower part of the Potsdam Formation. Hinge -lines are tenuous and variable in orientation, and individual beds thicken and thin greatly through short distances. The most obvious fold at this locality is one of a series of irregular gentle undulations of bedrock, between which are small areas underlain by Grenville rocks or horizontal Potsdam strata. The hinge line of the fold trends approximately N40°E. Other folds in the area exhibit a similar trend ....... ". They suggested that the spatial relationship of many of these folds and internal soft sediment disruption of bedding to topographic highs of the Precambrian basement (in this case caused by a possible west-side down northeast-trending fault 2 miles to the southeast near Theresa village) might have produced "rapid downslope movement during and closely following sedimentation" (Barber and Bursnall, op cit.).

Drive up the hill (fault scarp referred to at Stop 4)
Drive up the hill (fault scarp referred to at Stop 4) into the center of Theresa.

STOP 5: Contact between Grenville gneisses and non-typical "Potsdam" sandstones.
Pass the reservoir for the Theresa village hydro plant and a large, overhanging outcrop on the right (unfortunately due for demolition).
This is Stop 5, but parking is restricted so continue across a bridge, find a convenient parking space and walk back to the outcrop.
This area exhibits considerable relief of the Proterozoic surface (consider the elevation change between this locality and Stop 4) and the local configuration of the unconformity reflects this. The contact between sandstone and weathered basement gneiss dips moderately to the east from a high point at the western end of the outcrop. Significant discordance in bedding attitude exists between the low dip of well-bedded and color banded "typical Potsdam" at the highest parts of the outcrop to moderate easterly dips at road level. A bluff overhanging the road exhibits well-bedded sandstone overlying a heterogeneous breccia of quartz-arenite at the base. The larger clasts are of quartz and sandstone and towards the base, within a few feet of the unconformity, thin pebbly horizons are present. The weathered surface suggests the possibility of large sandstone blocks or rafts encased in an otherwise structureless mass and healed micro-faults are present towards the top of this lower section.
These features suggest a period of instability and possible slumping prior to the deposition of the well-bedded sandstones in the upper part of the exposure. Barber (1977) suggested that penecontemporaneous faulting might be the cause for the lower disrupted material and, although the gneiss-sandstone relationship here might be explained by initial dip of the Precambrian erosion surface, the existence of non-typical basal Potsdam Sandstone at this stop raises the possibility of a pre-Potsdam but post-Grenville depositional period accompanying fault-related deformation. This interpretation requires the existence of a cryptic depositional break within the outcrop and that the presumed slumping is not intraformational with respect to the present exposed section. <

Pass Payne Lake on the left at approximately 7.5 miles.
The complexly deformed Payne Lake alaskite body underlies the topographic high to the north (see Tewksbury, Trip A5, this volume).

Drive through the village of Oxbow.
Continue on Route 25, which continues as Route 52 in St. Lawrence County, passing through Wegatchie and closely following the path of the Oswegatchie River. Note that the flow is to the southwest here - at a position upstream of a major change in direction at Oxbow, from where the river heads northeastwards to the St. Lawrence at Ogdensburg.

Pass the "mint-with-the-hole" statue and the village park on your right.

STOP 6: The Rock Island Roadcut
Complex relationships of sandstone to gneiss.
This outcrop is perhaps one of the most intriguing in the North Country. It is featured in Van Diver's "Rocks and Routes of the North Country" and is a common stopping point for field parties visiting the area. Our main interest here is to characterize the relationship of the presumed Potsdam Sandstone to the Grenvillian gneisses which at the upper part of the roadcut are calcitic marbles. This deep roadcut provides magnificent exposure and is one of the better outcrops in illustrating the variety of marble - sandstone relationships present in the region.
At the southeast end of the cut, a well-bedded quartz arenite illustrates the attractiveness of the Potsdam sandstone erosional remnant interpretation. However, the very complex relationships of the sandstones with the "underlying" marbles invite alternative explanations to a simple erosional unconformity relationship. Moderate dips (30°), angular marble clasts in quartz arenite, thin sandstone dikes extending outwards and upwards from contacts, and changes in composition of the sandstones close to the marble have all contributed to a karst surface depression infill (Van Diver, 1976). Some of the contact relationships in this section have been used as evidence for structural control of deposition and basement remobilization (Bannerman in Carl and Van Diver, 1971).
Contact zones need to be carefully examined. Iron oxides and iron pyrites armor many of the surfaces, and the potential significance of angular marble fragments, subtle brecciation features particularly in the northern sections (perhaps, autobrecciation), matrix supported conglomerates (upper west side of northern section), etc., are easily overlooked. A spectacular tourmaline-rich breccia in the latter area further suggest a protracted and complex history for this section. Evidence of significant post-arenite deformation is present at many localities.

STOP 7. The Richville breccias.
BEWARE OF FAST MOVING TRAFFIC!
Please note that description of this stop is repeated in Trip B2
Cross the road and visit the moderately high exposures on the northwest side first.
Karboski et al. (1983) described this outcrop this as containing a "flow breccia" at its base, followed by a densely consolidated breccia with an overlying highly deformed metaquartzite, overlain by an "orthoquartzite", which contains pebble-sized quartz clasts - possibly derived from the underlying metaquartzite. The breccias contain quartz clasts set in a hematite stained, medium grained arenite. Large (0.5 m) phacoidal blocks of the breccia are enveloped by thin shaly borders, the whole giving the impression of a shear zone.
This outcrop certainly inhibits any notion that the unconformity between Precambrian basement and overlying cover is a simple one!
Points to concentrate on are:
1) Possible shear fabrics in the lower part of the outcrop, in part defining the borders of coherent blocks of breccia
2) Compositional variation of clasts in the breccias
3) The relationship between and the textural character of the each of the recognized rock types
If the upper part of this outcrop is indeed comprised of rocks which are part of the Grenville basement as supposed by Karboski (1976) and Karboski et al. (1983) then the current disposition of lithologies seems not to be satisfied by a model that involves karst infill alone (Van Diver, 1976) as seems possible at Rock Island Road. It is possible, however, that the wall collapse of a large solution depression may have allowed a slab of basement to slide into the argillite filled basin. The presence of shear fabrics within the breccia may be accommodated by this model provided that these rocks were only partially lithified at the time.
Cross over to the vehicle and investigate the southern end of the outcrop on the southeast side of the road. Here, a narrow zone of sandstone breccia dips steeply through marble. One of the contacts is sheared indicating high angle faulting. Is there evidence for displacement sense?
[Note: if time permits an outcrop of marble on the northwest side of Route 11, a few hundred yards to the south should be visited. It contains narrow subvertical veinlets of arenite at the northeast end, which provide good evidence for solution cavity infill.]

STOP 8. Southwest of East Dekalb.
Please note that description of this stop is repeated in Trip B2.
Roadcuts due south of Dekalb further illustrate the complexities within these post-Grenville rocks. A long series of low exposures on the northwest side of the road contain well-layered marble (reclined folds at the north end) to the north which in the central section give way to a complex steep contact with rusty weathered arenaceous rocks. A number of small sandstone breccia wedges penetrate downwards into the marble in the vicinity, again supporting the solution-pocket infill model for the larger scale relationships seen elsewhere (e.g. Rock Island Road). Evidence for sulfide mineralization is present at some contacts, in common with the Rock Island Road locality (Elberty and Romey, 1990).
Bedding in the sandstone is irregular and breccia/conglomerates are common, particularly lower in the section a hundred yards to the south and at the base of the southernmost outcrop on the northwest side of the road. A poorly defined cylindrical structure exists in the latter section and may be seen on the top of a low outcrop of compact, rusty weathered, quartz arenite (compare with Stop 3).
Similar conglomerate and breccia occur in a large outcrop on the southeast side of Route 11. Quartz, quartz-arenite, and metaquartzite are common clast compositions and are similar to those at Stop B3 (Stop 9 in Fig. 1). In both the western and southeastern outcrops shaly zones could have been generated by shear and at the northern end of the latter bedding dips are steep (>60°; Karboski, 1977), yet again supporting the notion of significant post-depositional deformation .

A3: CAMBRO-ORDOVICIAN STRATIGRAPHY, SEDIMENTATION, AND ICHNOBIOLOGY OF THE ST. LAWRENCE LOWLANDS - FRONTENAC ARCH TO THE CHAMPLAIN VALLEY OF NEW YORK
J. MARK ERICKSON
Canton, New York 13617
This trip is being offered for the purpose of introducing students of geology to some of the interesting and important relationships to be found in the first Cambrian(?) rocks to be "properly" described on this continent. Indeed, the name Potsdam is the oldest recognized stratigraphic name in North America accepted under the terms of the Code of Stratigraphic Nomenclature. The unit is, however, not strictly homogeneous, nor are its age and stratigraphic relationships known throughout its geographic distribution. The aim of this field trip is to point out some of the stratigraphic, sedimentologic, paleontologic, and paleoenvironmental variety that has been included under the label of "Potsdam Sandstone" in the region of the type area, northern New York.
This field trip will span the North Country from Chippewa Bay to Champlain, New York, (Figure 1) and will emphasize the basal units in the Paleozoic sedimentary cover of the basement. During its progress the guide will attempt to point out relationships between bedrock and the activities and deposits of the Wisconsinan glaciation which covered the entire field area. The trip will be entirely within the St. Lawrence Lowlands physiographic province as used by Fisher, 1977 (Figure 2).
Please note that the articles in support of this trip (Erickson & Bjerstedt; Erickson; and Erickson et al.) follow this road log.
ROADLOG
In this road log one will find, associated with each stop description, a number of questions that are best addressed by relationships at that particular stop. To stimulate thought and discussion participants are encouraged to make their own observations in an attempt to answer these and any others that arise in the process. The author assures you that he does not have answers to most of these!
Questions to be raised by this field trip:
1. What is meant by "Potsdam" - how well defined is the unit? Is the name being applied properly? Is misapplication preventing better understanding of regional tectonic and depositional histories
2. What is the age of the Potsdam Sandstone?
3. What depositional environments are involved in the Potsdam Fm.?
4. What are the relationships between the Potsdam-Theresa-Ogdensburg Formations?
5. What was the biota of the Potsdam-Theresa interval?
6. What was the paleoecology of the ichnotaxa (and of the trace-making organisms) found in these rocks?
7. Is the first appearance of trace fossils in regional rocks indicative of evolutionary change or of depositional environment?
8. What are the stratigraphic relationships of the formation?

A3: CAMBRO-ORDOVICIAN STRATIGRAPHY, SEDIMENTATION, AND ICHNOBIOLOGY OF THE ST. LAWRENCE LOWLANDS - FRONTENAC ARCH TO THE CHAMPLAIN VALLEY OF NEW YORK

STOP 1. St. Lawrence County Court House. (Figure 3)
Photo stop - no hammers please! The field trip begins appropriately at this classic structure because it contains most of the impressive elements of the Potsdam Sandstone as it occurs in the stratigraphic/lithographic type locality in the vicinity of Potsdam, N.Y., 10 miles to the East. The edifice also demonstrates many of the uses of the Potsdam and the skills of the quarry craftsman.
Emmons (1838, p. 214; 1842) named this unit in the Report of the Survey of the 2nd Geological District of New York. Quarries of the Potsdam are no longer accessible; however, the lithologic character of the "type" Potsdam is easily seen in this structure.
The rock is a fine-to-medium grained, well-rounded, well sorted, laminated, plane bedded or cross-stratified, hematitic, silica cemented orthoquartzite. It has very unique decorative properties because quartz grains were individually coated by hematite before the silica cement was introduced. For this reason the red coloration is protected from weathering, thus facades do not become streaked or stained as is the case with some hematitic or limonitic building stones having calcitic cement that contains the oxides or with pyritiferous limestones and sandstones.
The gray ashlar blocks of the courthouse are a Precambrian unit known as Gouverneur Marble. Red trim is all Potsdam Sandstone. Both were produced in St. Lawrence County. Please note that the newly completed addition to the courthouse attempts to use the same color themes but employs man-made materials rather than native building stone.
Questions to be raised at Stop 1, in particular are:
1. What are the lithologic properties of the Potsdam Sandstone?
2. What depositional environments are represented in the "type" Potsdam Sandstone?
3. Do the rocks contain fossils - either ichnofossils or body fossils?
4. What primary sedimentary structures are present?

Note sandstone facade on Canton Municipal Building on left.

Cross Grass River
The Grass River is one of several northward-flowing rivers whose headwaters are in the Adirondack Highlands. These are tributary to the St. Lawrence River approximately 20 miles to the North. Several have major power dams or paper mills on them thus being developed to the degree that the original character and fishery of the river has been lost. Canton's water supply is drawn from the Grass River.

The route passes along the Canton phacolith
The route passes along the Canton phacolith, a body composed of alaskite and surrounded by marble and paragneiss, all presumably Grenvillian age (Bloomer, 1965; 1967).

Outcrops of Canton Alaskite are visible at crest of hill.

Whalebacks of alaskite and gneiss
The entire region has been glaciated multiple times, most recently during the Wisconsinan Stage of the Pleistocene. Topography of both bedrock and surficial material reflect that process. Outcrops of alaskite and gneiss having smooth glacial polish and protruding from surrounding till are referred to as "whalebacks" because of their appearance and morphology.

Prominent valleys through the alaskite-gneiss terrain
Differential scouring of softer marble and subsequent valley filling by alluvium and bog deposits has produced prominent valleys through the alaskite-gneiss terrain. The bus will cross such a valley at the given mileage. The next stop lies within such terrain.

STOP 2. Potsdam Outlier Or Grenvillian Quartzite? (Figure 4)
Bus will turn onto gravelled parking strip on W. side of the highway. Disembark and carefully cross this busy highway to examine low outcrops in roadcut on east side.
In the North Country no trip in the Potsdam would be complete without visiting one of the region's outcrops of enigmatic sandstone. Cushing (1916) included this hill as an OUTLIER of Cambrian Potsdam Formation overlying Grenvillian marble.
Bloomer (1965,1967), after structural mapping and petrographic studies of included minerals, concluded that the quartzites mapped as outliers were in structural and mineralogical equilibrium with enclosing Grenvillian rocks, implying for the sandstones a Precambrian age as well. Others (e.g.. Brown, 1967) have considered the quartzites to be collapse fillings of, or deposition in, a karst developed on Grenvillian marbles, or fillings of cavities created by hot, high-pressure, acidic brines conducted through the porous Potsdam (see trips by Selleck, and by Bursnall and Elberty in this volume for further discussion). As one examines this outcrop bear in mind that the type Potsdam is an outlier of quartzite on Grenvillian rocks!
Careful examination of the outcrop will reveal at least six lithologic units (including those to be seen in the continuation of the roadcut approx. 75 yards to the north). The lowest unit is white, buff-weathering, fine- to-coarse grained, laminated, trough cross-stratified quartz sandstone, 3+ feet thick dipping NE at 28 degrees.
Unit 1 is overlain disconformably(?) by laminated, plane bedded, more friable, pink and white quartz sandstone. Unit 2 persists through thickness of approximately 20" grading into unit 3, a more massive expression of the same lithology. A 3" set of trough cross-strata that occurs 4" below top of unit 2 may be filling a channel. Unit 2 contains laminae packaged in coarsening-upward bundles one to three inches thick.
Tracing unit 2 toward to South end of the outcrop reveals at least two instances where it is brecciated and fills vertical interstices on planes of displacement(?). Flow lamination in the sand matrix parallel (?) to the plane of movement suggests deposition of the matrix by fluid but indices for the direction (stratigraphically up or down) of fluid motion are lacking. Such autobreccias constitute a 4th unit. Lest there be question regarding structural motion on these surfaces, there are well-developed, if a bit weathered, slickensides in the upper portion of the south end of the outcrop.
Walking northward will bring one to a low outcrop of siliceous autobreccia and finally to a second laminated sandstone, the exact relationship of which is unclear.
Coloration in the Potsdam Sandstone is often a point of interest, even contention. Lower surfaces of pink, hematitic(?) color bands on this outcrop sometimes transgress bedding planes and show sharp boundaries having micro-irregularities similar to those of stylolites. Coloration seems diagenetic not primary depositional in origin in this case. Such may not always be the case for Potsdam coloration, therefore each outcrop should be examined without prejudgment in the matter of color.
Stratigraphic relationships of many sandstone outliers, including those of the type Potsdam (Reed, 1934), to the main lithosome are unknown. Most workers today discuss informally the red, pink (or peach in Canada), pink and white, and white Potsdam. The terms lower and upper Potsdam are used as well. Although relationships among these units are unclear, paleoenvironmental interpretations are likely to eventually afford means for distinction.
At this outcrop consider the following questions:
l. What depositional environments are represented by the various units?
2. What are the structural relationship of the outcrop?
3. What might the sources of coloration in the sandstones be?
4. Are trace or body fossils present?
5. What is the age of this sandstone?

Cross Oswegatchie River.

Note road cut exposure of Precambrian granite gneiss.

Village of Heuvelton.
This region of St. Lawrence County has been settled by Amish groups so it is probable that we will see horse drawn buggies or other farm equipment while driving along the south side of Black Lake. These gentle folk are superior craftspersons who contribute much to the diverse culture of this county.

Note stone house in Federal architectural style on right.

Pink and white orthoquartzite
Note outcrops of pink and white orthoquartzite on both sides of the road. There are no fossils in this rock and it resembles some of the laminated units seen at the last stop. Note the terrain change ahead as bus crosses into metamorphic country rock.

Grenvillian gneiss.

White, poorly bedded sandstone.

Gray gneiss with granitic dikes cutting outcrop.

Pope Mills.
Note outcrop of marble in the village as bus turns toward North.

Cross Black Lake at Edwardsville.

North Shore of Black Lake
The north shore of this long, narrow lake marks the edge of rather flat-lying, Paleozoic sediments

Exposure of Paleozoic sandstone.

Note use of stone in the new house on the right at corner.

Bedding plane exposure of white orthoquartzite
On left is a bedding plane exposure of white orthoquartzite having a striated, polished surface. It reveals no bed features, nor any fossils. Please note its elevation with respect to the outcrop of Precambrian gneiss 0.1 mi. ahead and to the left side of the road.

Escarpment cut in Paleozoic sediments
While driving note the escarpment cut in Paleozoic sediments on the right in the trees and the wide valley to the left in which Precambrian granitic gneiss whalebacks stand as evidence of proximity to the Precambrian-Paleozoic contact.

Climb through the outcrop to be visited.
It is a road cut made where Hwy. 12 crosses the escarpment just viewed. Take this opportunity to preview the outcrop which we will spend some time examining.

STOP 3. "White" Potsdam and Theresa fm. are exposed in this important outcrop (Figure 5).
PLEASE USE PROFESSIONAL CARE - WATCH FOR TRAFFIC AND FOR LOOSE ROCK ON THE OUTCROP.
This outcrop provides one of the most complete exposures of the Precambrian-Potsdam-Theresa transitions in the northwestern St. Lawrence Adirondack Lowlands on the American side of the St. Lawrence River. That is not to say that the section is chronostratigraphically complete; almost certainly it is not, because the more angular, poorer sorted, ferrugenous, often arkosic and siliceous-cemented sandstone facies generally associated with the older (lower) Potsdam are not present in the immediate vicinity. The red rocks exposed approximately 0.3 miles to the SE are Precambrian alaskitic gneiss. Pleasant Valley intervenes between the exposure now being examined and the Precambrian outcrop leaving the possibility that the lower Potsdam section has been removed by erosion.
Other local sections, however, preserve the transition into white Potsdam Sandstone through a few to several feet of quartz cobble conglomerate which marks a marine transgression that is probably younger than Dresbachian in this region. Its precise age is not yet well constrained (Fisher, 1977) in this location, yet lithologic relationships in northeastern New York (Fisher, 1977; 1982) and recent ichnobiostratigraphic studies by Yochelson and Fedonkin (1993) infer a Franconian or even a Trempealeauan age for rocks not containing species of the ichnogenus Climacticnites. No Climacticnites sp. have yet been recovered from the "white" Potsdam sandstones locally.
The trip first examines a relatively unweathered exposure of Potsdam-Theresa deposits created as a roadcut approximately 25 years ago. This section includes units 3 through 8 on the composite stratigraphic column given herein (Erickson and Bjerstedt). The Potsdam is white, cream or buff, brown-weathering, moderately sorted, fine to coarse, medium-to thick bedded, cross-stratified or laminated, calcite- or silica-cemented orthoquartzite. Current ripples and "herringbone" cross-strata suggest deposition under tidal conditions (see Erickson and Bjerstedt herein). Contact between Potsdam and Theresa is taken to be at the inception of dominant calcareous cement in grey, buff-weathering, more poorly sorted ferrugenous, thin- to medium-bedded, limey sandstones and sandy dolostones. Bioturbation becomes a controlling element of preservation of primary sedimentary structure at this point. Iron is often present as pyrite framboids. Originally these sediments were very rich in organics. Much of that original food resource was removed by trace-making organisms leaving rocks of the unique "Theresa aspect" in which bedding planes are formed between bioturbated sedimentation units seen in this outcrop.
Cross-strata and presence of Skolithos sp. suggest that the white Potsdam lithofacies originated as sandwaves built across expansive tidal flats subsequently reworked by shifting tidal currents. Varying eustatic conditions resulted in recurrence of such conditions a number of times during Theresa deposition. Thus a "white Potsdam" lithofacies of rather clean quartz arenite can be found in the Theresa repeatedly. The Skolithos ichnofauna is not, however, always contained in it. It seems the Potsdam lithofacies does not always carry the Potsdam Ichnofacies.
At this outcrop the two styles of ichnofaunal development - infaunal suspension feeders and infaunal deposit feeders - are recognized. Bjerstedt and Erickson (1989) and Erickson and Bjerstedt (herein) discuss these trace fossil relationships, particularly as they relate to energy of depositional environment and depth of burrowing. Here it is emphasized that body fossils are essentially absent from this unit so that knowledge of the biota is developed from the ichnofauna. The Potsdam was unable to support deposit-feeding organisms as it was too well-sorted, reflecting high energy conditions of deposition on the tidal platform. Theresa sediments, on the other hand, must have held a rich admixture of organic matter within their more muddy matrix. These are burrowed extensively to depths of more than 5 cm by a wide variety of trace-making organisms. These are illustrated in the accompanying article by Erickson and Bjerstedt (herein).
Questions to be considered at this stop:
1. What were the depositional environments of the Potsdam and Theresa Formations.
2. Why are there no body fossils in these rocks?
3. What is the significance of the depth of burrowing in the Theresa? (Does it reflect ability of the Burrowing organisms, food content of sediments, sedimentation rates, oxygen content, or other environmental factors.)
4. What types of organisms were the likely trace-makers?
5. What was the source for the organics being utilized by deposit feeding ichnofauna?

STOP 4. Weathered Theresa Formation. (Figure 5.)
In the weathered bedding plane exposures found along this roadcut and the scarp to the SE one finds a diverse ichnofauna preserved in hyporelief, or occasionally in epirelief, on bed soles and surfaces. Examples of Monocraterion sp., Phycodes flabelliforme, Planolites sp., Roselia socialis and perhaps of Cruziana sp., will be found here. Weathering along the scarp face represents approximately 10,000 years of development, whereas that along the roadcut may be much less. Apply the same questions examined at Stop 3.

STOP 5. St. Lawrence Sea Way Scenic View. (Figure 5)
Photo pause - 10 minutes. Islands in the St. Lawrence River are formed by Precambrian (Grenvillian) granitic gneiss which is elevated along the Frontenac Arch, a structural high that links the Adirondack Dome to the Canadian Shield proper. This view of the region is probably not unlike that which one would have seen during the Cambrian as the Sauk marine transgression crossed the region. Knobs of grenvillian metamorphic basement became islands about which conglomerate, and subsequently sandstone, were deposited as tidal currents swept between the islands.
The St. Lawrence River, now a "seaway" for ocean-going vessels, flows NE draining the Great Lakes of Canada and the U.S. The international boundary passes up the middle of the river here, but east of Massena, NY the river lies entirely in Canadian territory.
Note boulders of local and regional rock types.

Paleozoic calcareous sandstones of the Theresa Formation
You will be traveling on a surface held up by Paleozoic calcareous sandstones of the Theresa Formation. Note the appearance of this St. Lawrence Lowlands topography; it is typical of landscapes with very thin, or no, glacial drift remaining on it.

Note Precambrian gneiss.
Where loop closes on itself Precambrian gneiss lies NE of road and Potsdam SS has SW forming ledge behind garage. Contact not exposed but quartz pebble conglomerate occurs in wooded area to ENE of the side roads.

STOP 6. Section At Oak Point. (Figure 6)
The drive around the Oak Point loop has provided a typical example of many of the exposures along both Canadian and American sides of the St. Lawrence River in this immediate region. Exposures along the frontage road contain the Potsdam-Theresa contact.
This outcrop offers another opportunity to investigate the burrowing depths, bioturbation thicknesses, and trace fossil taxa involved in the transition to carbonate rich mudflat sedimentation in lower energy conditions (?) upsection. This section is noteworthy because it has produced one example of an arthropod trackway of large size probably assignable to the ichnogenus Protichnites as is discussed herein by Erickson and Bjerstedt. The trackway will be available for examination and discussion at this stop.

Note white sandstone bed in blue-gray Theresa
Note white sandstone bed in blue-gray Theresa Formation on right of road.

Slight deformation of Paleozoic strata
Slight deformation of Paleozoic strata can occasionally be seen in roadcuts such as that near Brier Hill.

Several exposures of Theresa Formation
Several exposures of Theresa Formation form roadside outcrops here.

Stone fences of upper Theresa Fm.
Stone fences constructed of slabby, upper Theresa Fm. begin to be a local hallmark in this region. They will be emphasized in the "Stone Fence Motel" that will be seen in about 15 miles on the LEFT (NW) side of the road.

Scotch Bush Road.
A small quarry opened in the "white Potsdam" (or Heuvelton) Sandstone lies 1.3 miles south along this road. It is now being used to store rubble, but it once presented a fine view of this unit.

Bedrock now is Ordovician limestone and dolostone.
Stratigraphically the trip has traversed the Theresa-Ogdensburg contact. Bedrock now is Ordovician limestone and dolostone. The highway here passes through a small (no admittance) private, abandoned quarry in the Ogdensburg Formation in which can be found domal stromatolites. The depositional setting of these rocks was described by Kerans (1977) and conodont faunas from two larger quarries in the formation were investigated by Judson (1981).

Stone Fence Motel on left.

Quarry in the Ogdensburg Fm.
Pass a large stone quarry (behind berm on left) in the Ogdensburg Formation (See Kirchgasser and Theokritoff, 1971). It is beyond scope of this trip.

Cross the Oswegatchie River
Cross the Oswegatchie River the confluence of which with the St. Lawrence lies in the city of Ogdensburg. Note the "Golden Dome", a high school hockey arena.

Bridge to Prescott, Ontario, CANADA.
Frequent views of the St. Lawrence Seaway and terrain formed on glacial Lake Iroquois sediments will be seen between Ogdensburg and Massena, NY.

Full view of Iroquois Dam to north.
Full view of Iroquois Dam, a water level control structure, can be seen to the north.

Sucker Brook drowned valley
Construction of the St. Lawrence Seaway raised water levels in the valley greatly. Many St. Lawrence River tributaries now have drowned valleys above their confluence. That of Sucker Brook, crossed here, and Brandy Brook are typical.

Valley of Brandy Brook.

Cole's Creek, the drowned valley now being crossed
Cole's Creek, the drowned valley now being crossed, marks a former channel of the Grass River drainage which was pirated eastward after the marine waters of the Champlain Sea were excluded from the St. Lawrence Lowland by isostatic rebound. Development of the present drainage followed.

To the LEFT (N) view a coffer dam
To the LEFT (N) view a coffer dam constructed across another abandoned channel of the Grass River. This dam is designed to keep the valley from being flooded by waters of manmade lake St. Lawrence.

Village of Massena.
There are several items of geological interest associated with Massena. It was the site of a major rapids in the St. Lawrence River which became the site for the Moses-Saunders power dam of the NY Power Authority and Ontario Hydro. Massena was also the epicenter of the 1944 magnitude 4.0 (Richter) earthquake of regional significance. The Massena Clay, a blue, marine clay deposited in the Champlain Sea, underlies much of the region. This deposit contains the marine bivalve mollusks Macoma baltica and Hiatella arctica, a modest foraminiferid (Katz, 1981) and ostracod (Erickson et al., 1984) fauna, and to the south at Norwood, N. Y, the skeleton of a Beluga whale was recently recovered by Bill Kirchgasser (Kirchgasser and Steadman, 993).

Visitor center of Eisenhower Lock
To the left is the visitor center of Eisenhower Lock, one of the sites where zebra mussels (Dreissena polymorpha) were first introduced to U.S. waters. Robinson Bay, northeast of the lock, will be the site of the $14 million St. Lawrence Aquarium and Ecological Center.
Inexpensive electric power from the NYPA project has made this the site of ALCOA, Reynolds, and GM plants producing and using aluminum. Some serious environmental problems have also been generated: the large earth moving project on the left is part of a PCB mitigation effort.

Biomass Poplar Plantation
Biomass Poplar Plantation, are experimental, quick-growing strain of the poplar to be used for wood chips which fire a heating plant. This project was spawned by the energy crisis of the 1970's when some institutions like Clarkson University installed wood-fired heating plants.

View of the Raquette River to the right.

Cross Raquette River.

Enter Akwasasne the Mohawk Nation.

Cross St. Regis River.

Cross Little Salmon River.

Village of Ft. Covington
At confluence of Little Salmon and Salmon Rivers.

Westville. The Salmon River here flows on bedrock.

Cross Salmon River.

Begin to climb onto the platform of a major delta
Terrane begins to "roll" at the approaches to the town of Malone and begins to climb onto the platform of a major delta built into the Champlain Sea (Clark and Karrow, 1984).

Cross the Salmon River
Cross the Salmon River, and begin to ascend hill on E. side of town.

STOP 7. Meagan Residence. (Figure 7)
Field trip members are the guests of the Michael Meagan Family. Walk up driveway and enter backyard through gate in fence. Please stay on path. Mr. Michael Meagan is the owner of the unusual Malone dubiofossils which we are here to view. The specimens, which are displayed near the pool, were discovered during excavation in 1992, and were recognized by Mr. Meagan to be unusual. He permitted removal of the specimens to St. Lawrence University where they were studied by Erickson.
Preliminary findings presented herein interpret these structures as slightly-transported fragments of algal mat with included trapped sediments. Please examine the specimens which are part and counterpart of a single block of laminated Potsdam Sandstone. During examination one may wish to keep the following questions (and others!) in mind.
1. What conditions were required to produce such an algal mat?
2. How much transport might they withstand?
3. Were there no animals present in the environment of deposition?
4. Could these be something other than algal/sediment features?
5. What is the age of this specimen?
6. Similar structures seem to be restricted to the Cambrian and very late Precambrian - why?

Malone delta built into glacial Lake Iroquois
You will climb again onto the plain of the Malone delta built into glacial Lake Iroquois (Clark and Karrow, 1984). From this vantage there is a commanding view of the St. Lawrence Valley to the North - the former basin of Lake Iroquois and later the Champlain Sea.

Entering Burke Center.
The careful viewer will see to the north-northeast a prominent elevation across the St. Lawrence Valley. This may be Covey Hill, a Potsdam Sandstone ridge against which glacial ice lay to dam glacial Lake Iroquois. The lake drained between approximately 12,000 and 11,500 B.P. (Pair and Rodrigues, 1993).

Cross an abandoned drainage through a deltaic platform
Again, cross an abandoned drainage through a deltaic platform related to the ancestral Chateaugay(?) River.

STOP 8: HIGH FALLS PARK. (Figure 8)
NO HAMMERS PLEASE.
This scenic stop affords the opportunity to view a more easterly exposure of the Potsdam Sandstone. Comparison with the sections seen previously at Pleasant Valley Road and Oak Point in St. Lawrence County will support the idea that the sandstone of the Potsdam thicken northeastward across the Laurentian Platform. Here more than 100' of section is exposed. As thickening occurs it is probable that age relationships within the formation become increasingly complicated. Trace fossils have assisted stratigraphers to make regional correlations and paleoenvironmental interpretations in the absence of body fossils.
At this stop one may wish to examine character of the Potsdam lithologies, bedding characteristics and contacts, weathering profile, and trace fossil content of the rocks. What paleoenvironments are suggested? Time allowed 1/2 hour. Please return to bus promptly when requested.

Cross Chateaugay River.

Rising out of ancestral Chateaugay River Valley
Rising out of ancestral Chateaugay River Valley, note retaining wall constructed of local sandstone. On the upland there is another view northward toward the St. Lawrence Valley and Canada. South of the highway lies a newly constructed substance abuse center, one of several penal facilities that have proliferated northward in the past decade.

Cross North Branch of Great Chazy River
The trip has crossed into the basin of the Great Chazy River, the North Branch of which is crossed here.

Trip crosses a deltaic sand plain
Again the trip crosses a deltaic sand plain, probably an element of the ancestral Chazy River system.

Cross Great Chazy River in Mooers Forks.

Modern floodplain of the Great Chazy River
Route winds eastward once gain at edge of the village where the modern floodplain of the Great Chazy River can be seen well developed south of the highway.

Cross Great Chazy River once more

Travel on surface held up by Potsdam Sandstone
Travel on surface held up by Potsdam Sandstone which underlies glacial deposits.

STOP 9. CLINTON FARM SUPPLY. (Figure 9)
Exposed in the north half of the parking lot and surrounding an abandoned quarry to the rear of the Clinton Farm Supply are bedding planes of the Potsdam Sandstone. Rocks here are assumed to be in the upper or Keeseville Member. These are medium bedded, cream to white, plane and cross-stratified, quartz arenites (Fisher, 1968).
This outcrop affords an exceptional opportunity to examine bedding plane features, including large scale ripple marks, trough cross strata, sand waves and associated ichnofossils. The unusual and abundant trace fossils are of particular interest. Some aspects of these rocks are very similar to the white sandstone facies seen at Pleasant Valley Road (Stop 2) and within the Theresa Formation at Oak Point (Stop 3) this morning. At first look the traces fossils seem unique, however.
Some of the paleoenvironmental and ichnological features of this outcrop are described in the accompanying paper (Erickson, Connett, and Fetterman, this volume) resulting from studies by the 1993 St. Lawrence Paleoecology Class. Relationships here give insights into some questions raised at previous stops as well as spawning new questions such as:
1. What organism produced the large traces?
2. What controlled their distribution?
3. How deeply did they burrow?
4. What is the relationship, if any, of burrows to the ripples in both space and time?
5. How did the trace makers feed, on what, and where? (e.g., were they filter feeders, suspension feeders, or deposit feeders?)
6. Is this Potsdam Sandstone? What age is it? Examine the outcrop thoroughly. Several bedding planes are preserved but the lowest surface, that displaying the ripples, is the most interesting. It continues on the south side of the road where some brittle-fracture patterns are present as well.

Climb again onto rich soils of the Malone paleo-delta.
Once a major potato-growing area, the presence of Popeye on the sign denotes that spinach is now the major crop. It is frozen on site for sale to several brands. Rotation of fields assures nearly steady production during the growing season.

East Branch of the Little Salmon River

Nicholville, NY on the St. Regis River.
The Nicholville Conglomerate Member (Postel, et al., 1959) of the Potsdam Sandstone crops out along the river near here. It is overlain by orthoquartzite which occurs along Hopkinton Brook, .75 mi N of Village of Hopkinton. Stratigraphic relationship between members are uncertain and distribution is local. As such, the Nicholville is one of three or four difficult-to-define, restricted, basal conglomeratic units that may be "Potsdam," but are more likely Precambrian. The Allens Falls Fanglomerate (Harris, 1988) is another such unit. Their examination is beyond the scope of this trip.

Cross West Branch of St. Regis River.

Note use of true Potsdam Sandstone in buildings
Note use of true Potsdam Sandstone in buildings of Clarkson University and the village museum and library. This rock came from quarries south of the village that are no longer available for study.

Cross the Raquette River.
Note church of Potsdam Sandstone on left when crossing island.

A4: THE LATE GLACIAL ORIGIN OF THE CLINTON COUNTY FLATROCKS
David A. Franzi, Kenneth B. Adams
Plattsburgh, New York 12901
Donald L. Pair
University of Dayton
The Clinton County Flat Rocks comprise a discontinuous, 5-kilometer wide belt of bare sandstone areas that extend approximately 30 km southeastward into the Champlain Valley from Covey Hill, near Hemmingford, Quebec (Figure 1). Created by catastrophic floods from the drainage of glacial Lake Iroquois and younger post-Iroquois proglacial lakes in the St. Lawrence Lowland more than 12,000 years ago (Denny, 1974; Clark and Karrow, 1984; Pair et a1., 1988), the exposed sandstone today provides a nutrient-poor, drought-prone habitat that is often covered by jack pine (Pinus banksiana) barrens. The relatively low-diversity jack pine community is maintained by fire, which has an important role in ecosystem regeneration. We will examine the deglacial events leading to the origin of the Flat Rocks by following the path of late glacial meltwater drainage from the divide between the St. Lawrence and Champlain drainage basins. We will also address on-going efforts to understand the linkages between the hydrogeology and ecology of the jack pine barrens and document the recent history of anthropogenic development in the Flat Rocks region. The trip will feature a visit to several sites in the southeastern portion of Altona Flat Rock on property owned by the William H. Miner Agricultural Institute. The area contains the remains of the "Million-Dollar Dam", part of a failed hydroelectric project begun by William Miner in 1910. Additional stops will examine the deposits and landforms that record deglacial events leading to the catastrophic drainage of Lake Iroquois and subsequent formation of the Flat Rocks. The text of this field guide is an expanded version of a previous field guide (Franzi and Adams, 1993) that was concerned exclusively with the geology and ecology of Altona Flat Rock.

A4: THE LATE GLACIAL ORIGIN OF THE CLINTON COUNTY FLATROCKS

STOP 1. Lake Fort Ann Beach Ridges.
Park at the gate at the entrance of the Miner Institute property and continue northward on foot along Barnaby Road approximately 100 meters (320 ft). Turn left into woods and proceed west for 150 to 200 meters (500-750 ft) up the eastern flank of Cobblestone Hill. The beach ridges occur at elevations between 175 and 205 meters (580 and 670 ft) above sea level (Denny, 1974).
The beach ridges on Cobblestone Hill were first described by Woodworth (1905a) and later by Denny (1974). The beaches consist predominantly of moderately rounded to well rounded, pebble to cobble gravel that is deposited in multiple, elongate, low-relief ridges that extend along the northern and eastern flanks of Cobblestone Hill between 175 and 205 meters a.s.l. (Figure 7). Individual deposits are typically as much as 1 meter high and 30 meters wide, and often extend laterally for more than 400 meters (Denny, 1974). The gravel is almost exclusively composed of Potsdam Sandstone that was presumably derived from the alluvial cobble to boulder gravel that composes Cobblestone Hill.

Cobble gravel that comprises the Lake Fort Ann beach ridges.
Low roadside excavations approximately 75 meters (250 ft) west of the gate expose the cobble gravel that comprises the Lake Fort Ann beach ridges. Near the crest of the ridge the angular, 1.3 to 1.2 meter (1 to 4 ft) diameter boulders that comprise the core of Cobblestone Hill can be observed at the surface. The remains of the "Million-Dollar Dam" can be seen on the right just southwest of the hill crest.

STOP 2. The "Million-Dollar Dam".
The "Million-Dollar Dam" and hydroelectric generation plant was completed on 11 March, 1913 and operated intermittently from 21 January, 1915 until its closure in 1922. A large hole was blasted in the dam shortly after William Miner's death in 1930 to permit Cold Brook to drain freely through the former reservoir. The Flat Rock sandstone pavement is exposed southwest of Cold Brook. The change from mixed deciduous, primarily oak, forest on Cobblestone Hill to jack pine barrens on Flat Rock is characteristically sharp at this location.
...establish an instrumented field station for undergraduate research and instruction in geology and environmental science at the Miner Dam site. A monitoring-well network, consisting of nine wells ranging in depth from 10 to 25 meters, was completed in May, 1992 between the northeastern portion of the former Million-Dollar dam reservoir and the Skeleton Dam (Figure 7). Water-level measurements were begun in late July, 1992 (Figure 8). Future plans include the installation of a weather station, an inflow stream gaging station, and expansion of the monitoring-well network. The field station will provide an important linkage between traditional and applied educational opportunities that addresses some of the unique geological and ecological aspects of the Flat Rock region.

STOP 3. "THE SCARPIT".
The "scarpit" is the local name given to the desolate landscape created by efforts to grout the porous boulder gravel slope of Cobblestone Hill (Figures 6 and 7). The surface consists of a thin (1.2 to 2.5 cm) layer of cement that was poured and raked between large boulders composed predominantly of Potsdam Sandstone. The trench that was dug for the grout curtain (Figure 4) can be observed approximately 100 meters west of the concrete road that parallels the former shoreline of the reservoir.

The first of nine observation wells
The first of nine observation wells drilled in May 1992 can be observed to the left near the tree line at the edge of the grout surface. The wooded area beyond the well is part of minor southeast-facing bedrock riser. The slope of Cobblestone Hill steepens and the boulder size increases to the northwest.

The concrete road ends
The concrete road ends and the access road bears sharply northeast and continues on the bedrock surface through the jack pine barrens.

The road crosses a surface-water supported wetland.
The road bed is deeply rutted where it crosses a wetland that contains 0.2 to 1.0 meters of organic soil. Observation wells located approximately 50 meters northeast and 70 meters southwest of the wetland indicate that the water table is usually more than 7.5 meters below the surface.

The road crosses a small channel
The road crosses a small channel that contains a large wetland. A concrete wall on the left (south) side of the road was constructed to prevent water impounded behind the "Million-Dollar Dam" to escape northward through this channel.

STOP 4. The "Skeleton Dam".
The partially completed "Skeleton Dam" was designed to augment flow to the reservoir impounded behind the "Million-Dollar Dam" (Figure 7). The dam impounds "Chasm Lake" (Gooley, 1980), presumably named for the deep gorge cut into a prominent sandstone riser at its northwestern edge.
The water level of Chasm Lake dropped more than 2 meters below the spillway of the Skeleton Dam during the summers of 1991 and 1992. What little surface flow reached the basin during the summer months was lost by evaporation and ground-water seepage from the basin. Water level measurements from nearby observation wells since late July, 1992 indicate that steep, eastwardly directed hydraulic gradients exist at the southeastern flank of Chasm Lake, providing support for the hypothesis that some water is being lost from the reservoir by groundwater seepage.

STOP 5. The Ellenburg Moraine.
The gravel pit at this stop is excavated into the eastern (ice-proximal) side of the moraine. The pit contains approximately 10 to 12 meters of interbedded sand, gravel and diamicton that overlies Potsdam Sandstone. Bedset thickness generally ranges from about a decimeter to just over a meter. The maximum elevation of the upper surface of the moraine at this location ranges between 290 and 297 meters a.s.l.

STOP 6. The Ellenburg Moraine.
The exposure at this location is on the west (ice-distal) side of the moraine. The exposure contains approximately 10 to 12 meters of interbedded fine to medium sand with minor gravel and silt interbeds. Bedsets range from a centimeter to a few decimeters thick and are commonly horizontally laminated or ripple-cross laminated. Thin silt or silty fine sand deposits occur locally as draped laminae. Ripple azimuths and the gentle dip of the strata indicate a westerly paleocurrent. The moraine deposits were probably deposited in a proglacial lake west of the moraine in the upper North Branch valley. A small sandplain at an elevation of about 290 meters a.s.l. at Ellenburg may represent a delta that was built by the North Branch into the western end of the proglacial lake.

Route 11 crosses the Chazy-Chateaugay drainage divide.
The most easterly of the Chateaugay Channels can be seen adjacent to and crossing the road over the next few miles.

STOP 7. Discussion Of The Chateaugay Channel System.

Cross the Chateaugay River

The Chateaugay channels are on the right.

STOP 8. Chateaugay Channels.
This stop is alongside one of a series of underfit stream channels referred to as the Chateaugay Channels by MacClintock and Stewart (1965). These channels are eroded in till and bedrock and trend east-west across the low relief of the south slope of the St. Lawrence Valley. The channels are present from elevations of about 400 m (1300') to 315 m (1040') and are graded to the west.
MacClintock and Stewart (1965), Denny (1974), and Clark and Street (1984) concluded that the channels were eroded along a retreating ice front and emptied into Lake Iroquois to the west. These channels do appear to be graded to the highest level of Lake Iroquois in the vicinity of Malone (Pair and Rodrigues, 1993).
Discussion at this stop will focus on the channel morphology, nature of the ice-marginal drainage, and the possible duration of the drainage events.

Village of Dickinson.
11B passes through morainal topography identified as the Fort Covington Moraine by MacClintock and Stewart (1965).

STOP 9. The St. Regis Esker-Fan Complex And Nicholville Channels.
This stop will illustrate the sequence of deglacial landforms characteristic of ice margins in this part of the St. Lawrence Lowland. Moraines and an esker-fan complex in the St. Regis River valley indicate that a lobate ice margin extended southward and ended in a local proglacial lake. The esker ridge attached to the subaqueous fan complex is 80 to 90 feet high and extends northward 2 miles. Esker-fan complexes are present in many of the north-south valleys along the northwestern flank of the Adirondacks. Moraines in the region were attributed by MacClintock and Stewart (1965) to their Fort Covington readvance. They suggested that this ice advance was equivalent to the Port Huron stade. Our studies suggest that the ice margin here is probably recessional in nature and post-dates the Port Huron stade.
Continued ice retreat along the Adirondack flank uncovered the north end of the St. Regis River valley and the water level of the local proglacial lake dropped. Northwest of St. Regis Falls at Nicholville, the ice margin was still grounded and a series of progressively lower ice-marginal channels (from 1050-950') carried drainage westward and emptied into Lake Iroquois. We are standing in the bottom of one of these channels. Subsequently, a northward-flowing stream constructed the Iroquois delta at Nicholville.
Discussion at this stop will center around the time-transgressive nature of ice retreat, the proglacial water bodies in this region, and the morphology of the characteristic landforms.

Proceed across the sand plain of the Iroquois delta towards Nicholville.

A5: RETHINKING GRENVILLE-AGE DEFORMATION - DUCTILE SHEAR IN GRANITIC GNEISSES OF THE LOWLANDS
BARBARA J. TEWKSBURY
Clinton, NY 13323
Grenville-age metamorphic rocks exposed in New York State are customarily divided into two regions, the Northwest Lowlands and the Adirondack Highlands (figure 1). The Lowlands are dominated by upper amphibolite to lower granulite facies metasedimentary lithologies; the Highlands are dominated by lower granulite to granulite facies metaigneous units. The Highlands-Lowlands Boundary lies along the Carthage-Colton Mylonite Zone, a major shear zone that juxtaposes the two terranes and exhibits evidence of a complex motion history. The youngest motion along the Carthage-Colton Zone has recently been dated at approximately 1098 Ma by Mezger et al. (1992).
Despite the dominance of metasedimentary lithologies in the Lowlands, a number of metaigneous units have figured prominently in various models for the structural history of the Lowlands. Chief among these are the 14 large bodies of leucogranitic gneiss collectively referred to in the recent literature as the Hyde School Gneiss, after exposures in the Hyde School body (Carl et al., 1990, Whitney et al., 1989; Mclelland et al., 1992) (figure 1). The Hyde School Gneiss bodies are complex domical structures scattered throughout the Lowlands. U/Pb zircon geochronology indicates that protoliths for the Hyde School Gneiss in a majority of these bodies formed ca. 1225-1230 Ma (Mclelland et al., 1992).
Traditional views portray the structural evolution of Proterozoic rocks in the Northwest Lowlands as a series of folding events at scales ranging from microscopic to regional as part of a series of contractional orogenic events stretching from Texas to Labrador over a time period from some time between 1300 and 1200 Ma to about 1050 Ma. These models attribute complex patterns in the distribution of lithologic units to the interference of fold wave forms of different ages and orientations. Shearing, when recognized at all, has been relegated to discreet and narrow zones and has not been previously thought of as a major kinematic element in evolution of Lowlands structures.
Over the past several years, I have evolved a very different view of deformation in the Lowlands, one in which regional ductile shear played a major role, and have argued that models for the formation of structures in the Lowlands must be consistent with the manner in which microscopic through macroscopic structures evolve when rocks undergo deformation involving a large component of ductile shear. Evidence for the importance of regional ductile shear has come from examining several bodies of Hyde School Gneiss, as well as a series of younger granitic gneisses in the Lowlands. The introductory paper for this field trip will first compare published models for the evolution of Lowlands structures, then briefly outline an alternative model consistent with structural features of the Hyde School Gneiss, and finally explore the evidence compelling us to think seriously about regional shear.

A5: RETHINKING GRENVILLE-AGE DEFORMATION - DUCTILE SHEAR IN GRANITIC GNEISSES OF THE LOWLANDS

Hyde School Gneiss of Canton body on the left.

The famed Snake Roadcut.
The marbles exhibit complex fold patterns, some of which may be sheath folds.

Good views of cliffs of Hyde School Gneiss
Payne Lake Fishing Access Site, where there are good views of cliffs of Hyde School Gneiss on the eastern margin of the Payne Lake body. Fields east of the Payne Lake body are largely underlain by marble.

STOP 1. Main foliation (Sm) in the Hyde School Gneiss
Main foliation (Sm) in the Hyde School Gneiss along the eastern limb of the Payne Lake body (figure 7).
Park at the gate on the west side of the road, and walk west along the State access at the edge of the field to the outcrops of Hyde School Gneiss (HSG) visible from the road.
The contact is not exposed but lies between non-resistant metasediments and resistant HSG at the west edge of the field. The best exposures lie along a very small stream bed in the first set of outcrops immediately south of the fishing access path. The stop description begins in the stream bed at the first set of HSG outcrops.
The HSG at this stop is a lineated and well-foliated pink leucogneiss with interlayered amphibolite. The main foliation (Sm) is subvertical and strikes parallel to the margin of the body, and the lineation (Lm) plunges steeply in the main foliation plane. Because the outcrops are dominantly quasi-horizontal glacially polished surfaces, the lineation is difficult to see. One of the only vertical foliation surfaces exposed at this stop lies in the stream bed, where it is clear that the lineation is a very nice quartz ribbon lineation.
Thin sections show that the main foliation is a well-developed shear fabric displaying sigma grains with core and mantle texture, quartz ribbons ramping from shear plane to shear plane, and dynamically-recrystallized grains. The fabric is well-recovered and shows polygranular quartz ribbons, no grain shape preferred orientation of fine quartz grains, and generally straight grain boundaries. Sense of shear is east side up.
The HSG contains abundant coarse-grained granite and pegmatite, and it is clear at outcrops such as this one that granitic liquids were present throughout the shearing history of the HSG. Some pegmatites are thoroughly sheared, streaked out parallel to Sm as bumpy chains of coarse K-feldspar porphyroclasts in the main foliation plane. Other coarse granitic phases are discordant and show no fabric at all. A particularly nice example of an intermediate state occurs on the flat part of the outcrop above the lineated surface along the stream bed. Here, coarse-grained granite is clearly discordant to the main foliation but is itself weakly foliated.
While much of the HSG in the Payne Lake body is devoid of amphibolite, localities such as this one at the margin of the body typically contain abundant interlayers of amphibolite. Amphibolite interlayers lie parallel to the main foliation, and have been sheared out and streaked out parallel to the foliation. It cannot be overemphasized that the current relationship between amphibolite and leucogneiss is structural.
Amphibolite layers are discontinuous along strike and are commonly segmented. Some of the layer terminations are clearly isoclinal fold hinges. A fine example of such a fold occurs in the stream bed immediately east of the large patch of junipers separating the stream bed from the higher outcrops extending to the south. Here, a biotitic amphibolite layer has been folded into an isoclinal fold with the main foliation lying parallel to the axial plane.
Outcrops stretching to the south show other important features of the interlayered amphibolites. As in many of the other bodies of the HSG, amphibolite layers are divided into blocky segments separated by medium- to coarse-grained granite. The granite separating the blocks is typically unfoliated or less well-foliated than the adjacent leucogneiss. A number of amphibolite interlayers in this large exposure show fold terminations, and many of the fold sets are not simple trains of isoclinal folds. While none are unequivocally sheath folds, many have outcrop patterns that could reflect sheath folding.

Ask permission to visit stops 2 and 3
Ask permission to visit stops 2 and 3 at the Raymon Farm on the corner of New Connecticut Road and County Route 22. Resistant rocks of the Hyde School Gneiss form a prominent knobby, wooded rise across the fields to the north of New Connecticut Road. The southern contact of the Payne Lake body with surrounding metasediments lies approximately at the break in slope below the wooded rise.

Newly excavated roadcut of serpentinized marbles.

STOP 2: Discordant foliation in the Hyde School Gneiss
Discordant foliation (Sd1) in the Hyde School Gneiss along the southern end of the Payne Lake body (figure 7).
Park along the road, and walk north across the field. Follow the farm track that rises from the field diagonally up across the contact at the break in slope marking the transition to more resistant HSG. Proceed to the top of the rise immediately west of the farm track. The stop description begins in the HSG outcrops at the top of the rise.
Figure 7 shows clearly that this locality lies at the southern end of the Payne Lake body, where the main foliation (Sm) in the HSG, as well as the compositional layering and the contact between HSG and surrounding units, swings around the end of the body. At this locality, Sm and the contact dip very steeply south and strike approximately N35W.
The most prominent feature in the dark pink leucogneiss at the top of the rise is a well-developed, steeply-plunging quartz ribbon lineation that is well exposed on quasi-vertical surfaces. Close examination of the outcrop shows a striking thing. The lineation is associated with a weak, sub-vertical foliation striking approximately N55E, parallel to the length of the Payne Lake body, not parallel to the margin of the body. The main foliation (Sm) is difficult to locate in this exposure, where the lineated fabric is well-developed and where there is no compositional layering in the HSG. Interlayered amphibolite is exposed to the northwest below the crest of the rise, and the orientation of the foliated amphibolite makes it very clear that the prominent lineated fabric is discordant to both the main foliation (Sm) and the compositional layering. We have named the well-lineated, discordant fabric Sd1 (the subscript "1" derives from the fact that we find a second discordant fabric of slightly different character but similar orientation in the Dodds Creek body, as described in the log for stop 4).
Thin sections show that Sd1 like Sm, is a well-developed shear fabric displaying sigma grains with core and mantle structure, quartz ribbons ramping from shear plane to shear plane, and dynamically-recrystallized grains. The fabric is well-recovered and shows polygranular quartz ribbons, no grain shape preferred orientation of fine quartz grains, and generally straight grain boundaries. Sense of shear is east side up. Sd1 is a distributed shear fabric but is not equally well-developed at all localities around the southern margin of the Payne Lake body. In some areas of outcrop, the most prominent fabric in the rock is the well-lineated Sd1 fabric; in other areas, the most prominent fabric is Sm.
In summary, the Payne Lake body exhibits two distinct shear fabrics, one parallel to the margins of the body (Sm) and one parallel to the long dimension of the body (Sd1). Along the eastern and western limbs of the body, the two fabrics are parallel to one another and are consequently particularly well developed, especially along the eastern margin (e.g., at the previous stop). We have interpreted Sm to have been the earlier fabric developed in a subhorizontal regional shear zone. As sheath folds grew, Sm was folded into very large folds with highly recurved hinges. Figure 1 shows the geometry of the Payne Lake sheath. Sd1 developed with a shear sense consistent with earlier shear directions as a younger shear fabric parallel to the axial plane of the growing sheath. Along the limbs of the sheath, Sd1 lies parallel to Sm (figure 4b); in the hinge region at the north and south ends of the body, Sd1 is discordant to Sm.

STOP 3. Sheath folds and late dike
Sheath folds and late dike with mylonitic fabric in units adjacent to the Hyde School Gneiss (figure 7).
This property is owned by the Raymon family at the corner of New Connecticut Road and County Route 22; ask permission before visiting this locality. Park along the road, and walk north across the field. The contact between the Payne Lake body and adjacent units lies at the prominent break in slope at the edge of the wooded area. This stop description covers exposures of units adjacent to the Payne Lake body in outcrops on the low shoulder north of the field but south of the Payne Lake body itself. The stop description begins in the cluster of outcrops at the top of the rise.
A variety of metasediments, including feldspathic quartzites, marbles, and garnet-sillimanite gneiss, are interlayered with leucogneiss in these outcrops. The contact here between HSG and surrounding metasediments gives every appearance of being gradational.
Compositional layering and the main foliation (Sm) in these units dip steeply and strike approximately N80W, parallel to the margin of the Payne Lake body. In the flat outcrops at the top of the rise, garnet-sillimanite gneiss exhibits both eye-shaped folds several centimeters across and refolded isoclinal folds. We interpret the eye-shaped folds as sheath folds. Sheath fold long axes and isoclinal fold hinges plunge steeply in the foliation plane, parallel to quartz ribbon stretching lineations in adjacent HSG. The presence of mesoscopic sheath folds provides additional supporting evidence for interpretation of the Payne Lake body as a large sheath fold.
Refolds in isoclinal intrafolial folds and tight to open folds in Sm also occur in this outcrop. A moderately well-developed foliation is locally developed parallel to the axial planes of these folds. The folds plunge steeply, and the axial plane foliation is subvertical and strikes approximately N50E, subparallel to Sd1 and to the long dimension of the Payne Lake body.
Walk east to the last major set of outcrops before the ground drops away to the farm in the distance to the southeast. A sub-vertical dike approximately 15 cm thick and striking N60E cuts interlayered metasediment and leucogneiss. The dike displays a prominent mylonitic fabric that is best developed within the dike itself but that does occur in the country rock on either side of the dike. The mylonitic fabric is subvertical and strikes approximately N50E, subparallel to the long dimension of the Payne Lake body and at a high angle to Sm in the outcrop.
Thin sections of the mylonitic fabric of the dike show sigma grains with core and mantle structure, quartz ribbons, and dynamically-recrystallized grains. The fabric in this dike is the least-recovered of the fabrics at Payne Lake. Serrated grain boundaries are common, and some grain shape preferred orientation of fine quartz is present. Some later cataclasis is also evident. Orientations of outcrop surfaces makes it impossible to locate the stretching direction of quartz ribbons in the field. Multiple sections, however, show that quartz elongation is best developed in vertically-oriented sections, suggesting a steep stretching lineation. Shear sense is east side up, consistent with shear sense on both Sm and Sd1. Based upon shear sense and orientation, the argument could be made that this fabric, and the axial planar fabric in the sheath fold outcrop, are likely Sd1 fabrics. The fact that the mylonitic dike fabric is relatively poorly-recovered suggests that it represents a late phase in development of Sd1.
The features at this stop have two implications. First, shear in the Payne Lake body apparently had a long history, developing from a major shear zone with regional shear fabrics (Sm) to sheath folds with axial planar shear fabrics (Sd1) to late, discreet zones of shear with poorly-recovered mylonitic fabrics (late phase Sd1 or Sd2). Second, intrusion of granitic liquids persisted until the latest phases of shear, and some were clearly important in localizing melt-enhanced shear. This raises the question of the importance of melt-enhanced. deformation in the overall development of the Payne Lake sheath fold.

Good views of the northern end of the Payne Lake body to the SW.

Bridge over the Indian River.
The river channel follows the Pleasant Lake Fault Zone (PLFZ), a major late brittle structure (figure 1). Slip along the PLFZ has removed half of the Dodds Creek body, leaving the body with a steep sided, half-dome shape. Cataclasis along the PLFZ significantly reduced the resistance of gneisses along the fault. Swamp and floodplain cover the entire width of the fault zone, and rocks within the fault zone itself are not exposed anywhere along the Indian River. Mylonites in the Lowlands, on the other hand, are not typically more weakly resistant than unmylonitized lithologies.

Good view of the N end of the Dodds Creek body
Good view of the north end of the Dodds Creek body "at 2:00". The contact between the HSG of the Dodds Creek body and the weakly resistant metasedimentary lithologies underlying adjacent fields lies at the base of the knobby exposures of pink leucogneiss.

STOP 4. Main fabric (Sm) and discordant foliation (Sd2) in the HSG
Main fabric (Sm) and discordant foliation (Sd1) in the Hyde School Gneiss along the northern end of the Dodds Creek body (figure 7).
This property is owned by Mr. Edmon Phalen in the farm next door; please ask permission to visit this locality. Park along the road, and walk to the outcrops on the knoll west of the road.
The HSG at this stop near the margin of the Dodds Creek body is a pink, medium- to fine-grained leucogneiss with abundant interlayers of amphibolite. Flat outcrops on the north side of the knoll near the barnyard have abundant interlayers of quartzite several centimeters thick. While both the Dodds Creek and Payne Lake bodies have been previously mapped as consisting entirely of leucogneiss and interlayered amphibolite, we have established that both bodies, in fact, contain significant metasedimentary interlayers. The Dodds Creek body contains both thin interlayers of metasediment, as at this stop, and two wide swaths of interlayered marble, quartzite, and garnet-sillimanite gneiss (the concentric half-rings in figure 1). The Payne Lake body also contains a prominent metasedimentary inter layer with a peculiar "ear" shape (also shown in figure 1).
The HSG at this stop is well-foliated parallel to compositional layering, and thin sections from outcrops at the top of the knoll show that this main foliation (Sm) is a shear fabric, as it is at Payne Lake. Fabrics display sigma grains with core and mantle structure, quartz ribbons ramping from shear plane to shear plane, and dynamically-recrystallized grains. The fabric is well-recovered and shows polygranular quartz ribbons, no grain shape preferred orientation of fine quartz grains, and generally straight grain boundaries.
Sm at this stop is sub-vertical and strikes N95E, parallel to the margins of the Dodds Creek body. Stretching lineations plunge moderately steeply in the Sm foliation plane. At the southern margin of the Dodds Creek body, quartz ribbon lineations have a somewhat more variable orientation, consistent with reorientation during development of a large sheath fold in Sm. Along the margins of the body, quartz ribbon lineations plunge steeply. Sense of shear along the margins is east side up, as it is at Payne Lake.
A number of prominent discreet ductile shear zones several centimeters thick occur in the HSG at this stop and elsewhere in the Dodds Creek body. These zones are sub-vertical and strike N40E, approximately parallel to the long dimension of the Dodds Creek body. At the north and south margins of the Dodds Creek body, the mylonitic fabric of these zones is clearly distinct from the main shear fabric (Sm), because it is discordant to Sm. As at Payne Lake, the two fabrics can be difficult to distinguish from one another where they are quasi-parallel along the long margins of the Dodds Creek body. There are four significant differences between the main foliation (Sm) and the younger discordant mylonitic fabric. First, Sm is a distributed shear fabric, moderately well-developed to well-developed over zones 10's to 100's of meters wide. The discordant fabric, one the other hand, is distinctly domainal, occurring in ductile shear zones several centimeters thick. Second, the discordant fabric is clearly a mylonitic fabric in outcrop; the taffy-like appearance stems from abundant quartz ribbons and dynamically-recrystallized grains. Despite the fact that Sm is not as clearly mylonitic in outcrop, thin sections show unequivocal shear fabrics. In fact, when one is hunting for foliations in lichen-covered outcrops without amphibolites in the Dodds Creek body, it is very easy to latch onto the discordant fabric as the main fabric, because it is so easy to see. One must be careful to look for both fabrics. Third, the discordant fabric is only poorly-recovered. Serrated grain boundaries are common, and pronounced undulose extinction and grain shape preferred orientation of fine quartz are present. Fourth, and most interesting, the sense of shear in this discordant fabric is opposite from shear both on the main foliation (Sm) in the Payne Lake and Dodds Creek bodies and on the discordant fabric (Sd1) in the Payne Lake body. Every sample we examined from the discreet ductile shear zones shown west side up and slightly oblique sense of shear. We named this fabric Sd2, presuming from its un-recovered character and opposite shear sense that it is younger than Sd1 at Payne Lake. Figure 4c shows the geometry of Sd2in the Dodds Creek body.
As at Payne Lake, melt-enhanced deformation seems to have been important in late shearing at Dodds Creek. Several of the ductile shear zones at this stop are developed in what appear to be granitic dikes injected across Sm roughly parallel to Sd2.
We have found only limited evidence at Dodds Creek for an older pervasive discordant fabric (Sd1) similar to the one discovered in the Payne Lake body. At this stop, HSG exposed on the sloping outcrop surface below the phone pole shows a very weak pervasive fabric discordant to Sm and roughly parallel to the long dimension of the Dodds Creek body. Exposures along the Indian River immediately adjacent to a spur of the Pleasant Lake Fault Zone at the northern end of the Dodds Creek body show fabrics of similar orientation related to folds much like those at stop 3 in the Payne Lake body. Thin sections show that these are weakly-developed shear fabrics.
The HSG at this stop and at many places in the Dodds Creek body is laced with fracture swarms oriented approximately parallel to the Pleasant Lake Fault Zone. Thin sections show nice cataclastic textures. It is important to note that, while intensity of cataclasis does increase with proximity to the Pleasant Lake Fault Zone, intensity of ductile shear fabric development does not.
Evidence from the Dodds Creek body reveals an even more protracted history of ductile shear than that suggested by work in the Payne Lake body. Fabrics in the Dodds Creek body are consistent with development of Sm in a regional subhorizontal shear zone. Sheath fold development followed, with production of weak axial planar fabric (Sd1). Shear sense reversed, and discreet ductile shear zones developed but did not have time to recover before they were affected by cataclasis. Shear sense reversal and progression to brittle deformation is consistent with late extensional unroofing in the Lowlands.

Good views of the Pleasant Lake Fault Zone
Good views of the Pleasant Lake Fault Zone to the right of the road, with rocks east of the PLFZ underlying the wooded rise beyond the river.

Farm for permission for STOP 5.

STOP 5. Shear fabrics in biotitic augen gneiss
Shear fabrics in biotitic augen gneiss and surrounding metasedimentary lithologies immediately west of the Beaver Creek Fault Zone (figures 1 and 5).
Park on the right hand side of the road. This property is owned by the Amish farm on the north side of the road and back about 0.6 miles; please ask permission to visit this locality.
Walk into the field to the south of the road to the crest of rounded knobs of granitic gneiss about 1600' from the road, bypassing the wooded knoll approximately 1050' from the road.
Figure 5 shows a condensed and generalized geologic map of the Beaver Creek region based on an excellent and detailed map by Brown (1989). Several aspects are pertinent to this stop. First, granitic gneisses of two different ages appear in the region. The ca. 1225-1230 Ma Hyde School Gneiss is exposed in two bodies, the larger Hyde School body and the smaller Hickory Lake body. The other granitic gneisses in the region are younger than the HSG, having been intruded ca. 1150-1170 Ma. Second, while controversy rages over whether the HSG was originally plutonic or volcanic, no one disputes the plutonic origin of the younger granitic gneisses in the Beaver Creek region. Third, the region is divided into a number of elongate zones by northeast-striking faults, including the Hickory-Mud Lakes Fault, the Beaver Creek Fault and the Pleasant Lake Fault (the northern extension of the fault that cuts off the Dodds Creek body, as described at stop 4). Fourth, outcrop patterns of both metasedimentary and metaplutonic units lying immediately west of the Beaver Creek Fault Zone (BCFZ) are attenuated and elongated NE-SW, while similar units have larger, more irregular outcrop patterns farther northwest, suggesting the possibility of major ductile shear in the zone west of the BCFZ. Fifth, both the granitic gneisses and the metasedimentary units immediately west of the Beaver Creek Fault Zone are well foliated and display the "main regional foliation". This stop will give us a chance to study the character of the main regional foliation in several lithologies other than the Hyde School Gneiss.
At this stop, we will examine the most northerly of a series of seven elongate granitic gneiss bodies lying immediately west of the Beaver Creek Fault Zone (figure 5). This granitic gneiss is not only different in age from the HSG but also different in character, being a pink to grayish-pink, coarse-grained biotite-quartz- oligoclase-microcline gneiss with distinctive microcline augen.
These gneisses are spectacularly lineated - quartz ribbons lie like pieces of linguini on the steeply-dipping foliation surfaces exposed on the knoll. The lineations are best viewed on the sub-vertical faces of the east side of the knoll. Lineations plunge approximately 25, 40E.
The foliation carrying the lineation is the main regional foliation and shows characteristics that indicate formation by ductile shear. In thin section, the foliation shows clear fabric asymmetry in sigma grains and ramping quartz ribbons. Relatively coarse grain size in porphyroclast tails suggests a period of annealing following development of the main shear fabric. By contrast, the early shear fabric in the HSG of the Payne Lake and Dodds Creek bodies is recovered but not well-annealed. Shear sense in the Beaver Creek granitic gneisses shows consistent sinistral strike slip with a small component of east side down motion along subvertical planes striking approximately N40E. The fact that the gneiss bodies are elongate parallel to the main shear fabric in the rocks suggests that the individual bodies may have been intruded into a developing shear zone. Several of the bodies farther southwest (figure 5) that show only poorly-developed shear fabrics may have been intruded either relatively late or into zones that did not experience as much subsequent shear strain.
As in the Payne Lake and Dodds Creek bodies of the Hyde School Gneiss, the granitic gneisses west of the Beaver Creek Fault Zone show evidence in thin section of additional shear fabrics younger than the shear fabric of the main regional foliation. Some samples show a younger well-recovered but unannealed shear fabric. This fabric displays classic core and mantle structure around sigma porphyroclasts, polygranular quartz ribbons, and grain size reduction. This younger fabric appears to lie parallel to the main foliation. Shear sense consistently shows a component of sinistral strike slip.
Some thin sections show a third shear fabric, this one an unrecovered fabric. This fabric is characterized by quartz grain shape preferred orientation, biotite fish, and rare feldspar sigma grains. Sense of shear is opposite that shown by earlier phases and has a component of dextral, rather than sinistral, strike slip.
Interestingly enough, the dextral shear sense observed on this youngest shear fabric is, in fact, the sense of shear that one might infer from the geometry of the sigmoid east of the Beaver Creek Fault Zone (figure 5), and it is also the same as the sense of shear that we have suggested for the Pleasant Lake Fault Zone where it truncates the Dodds Creek body farther southwest. Late formation of the sigmoid is consistent with the results of our reconnaissance work in the sigmoid, which suggest that formation of the sigmoid postdates development of the main foliation and lineation in that region.
Multiple shear fabrics suggest a protracted history of ductile shear, much as we observed in the Payne Lake/Dodds Creek region. Changes in shear direction also suggest a complicated kinematic picture.
Walk 240' southwest from the crest of the knoll. While the contact itself between granitic gneiss and surrounding metasediments is not exposed, outcrops of metasediment lie very close to granitic gneiss on the east side of the knoll. As you walk southwest, examine the character of the foliation in the marbles. The foliation in the marbles and calc-silicate gneisses is defined primarily by compositional layering and lies parallel to the prominent lineated foliation in the augen gneiss. One of the striking aspects of these rocks is that spectacularly lineated granitic gneisses with well-developed shear fabrics lie within centimeters of metasedimentary lithologies that show absolutely no microfabric evidence of ductile shear.
The only fabric asymmetry that we noted in the metasediments occurs in the outcrop of marble 240' southwest of the knoll where we first examined the granitic gneiss. This rock is a marble with quartz lozenges several millimeters to centimeters in size floating in a sea of coarse, equant calcite grains. While the calcite aggregate preserves absolutely no record of the shear that produced the spectacular lineations in the adjacent granitic gneisses, many of the quartz lozenges have a distinctly asymmetric shape. The lozenges are sigmoidal in shape and ramp from one foliation plane to another. Shear sense is left lateral with a small component of down-to-the-east motion. This sense of slip is consistent with that observed for the earliest microfabrics in the granitic gneiss.
Well-lineated rocks with good kinematic indicators appear to occur primarily in the granitic gneisses of the region. The metasediments we examined here and elsewhere in the Beaver Creek region preserve essentially no kinematic indicators, even in locations within centimeters of highly-sheared granitic gneiss. Several factors may be involved. If melt-enhanced deformation was important during shear, the granitic material may have concentrated the shear, leaving adjacent metasediments with comparatively low shear strains. Second, quartzofeldspathic aggregates are ideal for preserving the kinds of kinematic indicators associated with ductile shear. Marble-bearing metasediments may, in fact, have accumulated as much shear strain as adjacent granitic gneisses, but shear fabrics may have annealed completely in the metasediments. Regardless of the cause, the effect is an important one to note and suggests that trying to sort out the history of regional shear in the Lowlands by examining the metasedimentary lithologies may well be an exercise in frustration.
In summary, the "main regional foliation" is clearly a shear fabric in both the well-foliated and lineated granitic gneisses we observed in the Beaver Creek Region and in the Hyde School Gneiss of the Payne Lake and Dodds Creek bodies, despite the fact that the Hyde School Gneiss is considerably older. Granitic gneisses of both ages also show conspicuous evidence for protracted ductile shear with complex shear histories. All of the evidence points toward the importance of ductile shear across the Lowlands over a protracted period of time in development of both major and minor structures.
Walk approximately 200' toward Beaver Creek to small, rounded outcrops of gray to white marble. You are standing right at the edge of the Beaver Creek Fault Zone, which is very much like the Pleasant Lake Fault Zone that we saw at stop 5 - no outcrop and lots of creek and swamp. Close examination of the marbles in these outcrops reveals little in the way of fault zone features, despite proximity to the Beaver Creek Fault Zone. The lack of major cataclastic features in outcrops immediately adjacent to the Beaver Creek Fault Zone is also reminiscent of the Pleasant Lake Fault Zone.

Cross Beaver Creek and the Beaver Creek Fault Zone.
The lack of outcrop in the weakly-resistant cataclastic rocks of this late fault zone is similar to that along the Pleasant Lake Fault Zone.

Cross the Oswegatchie River.

Crossing the "Race Track".
This low area of fields and swamps sweeping in a broad arc marks the weakly resistant metasedimentary rocks bordering the more resistant Hyde School Gneiss of the Canton body. The road climbs out of the Race Track onto HSG, which crops out in abundant rounded knobs.

STOP 6. Low pink outcrop on the east side of the road.
Lineated Hyde School Gneiss of the Canton body (figure 7).
If time permits, we will stop briefly to examine well-lineated Hyde School Gneiss of the Canton body at this locality.
HSG in the Canton body is lithologically similar to that in the Payne Lake and Dodds Creek bodies, but the orientations of lineations are conspicuously different. Lineations in the Payne Lake and Dodds Creek bodies plunge very steeply, consistent with the vertical orientations of the sheaths. Lineations in the Canton body, on the other hand, plunge moderately to shallowly throughout much of the body. Lineations at this locality plunge approximately 25, S60W, an orientation consistent with the overall shallow plunge of the complex Canton body finger.
Some publications have portrayed the Canton body as a south-southwest plunging structure, e.g., Foose's "Loch Ness Monster" model that interprets the Canton body and the Gouverneur body as two eroded "humps" connected in the subsurface (figure 2). Orientations of both foliations and lineations in the Canton body, however, suggest that a shallowly west-southwest-plunging overturned structure is a better interpretation (figure 1). Preliminary data from our on-going work on the Canton body show shear fabrics similar to those in the Payne Lake and Dodds Creek bodies, and we would argue that a shallowly west-southwest-plunging sheath fold is a better interpretation for the large-scale structure of the Canton body. Preliminary thin section analysis on samples collected during summer 1993 suggests that shear sense in much of the Canton body is top side down to the west.
Work in progress shows fabrics in this part of the Canton body to be more like those in the Beaver Creek region than those in either the Payne Lake body or Dodds Creek body. Fabric asymmetry is present in ramping quartz ribbons and relict sigma grains with coarse asymmetric tails, but fabrics are strongly annealed, as they are in granitic gneisses of the Beaver Creek region. Fine, dynamically recrystallized grains, so common in the Payne Lake and Dodds Creek bodies, are rare in the Canton body.

STOP 7: Hyde School Gneiss of the Canton body
Hyde School Gneiss of the Canton body and garnet-sillimanite gneiss in adjacent metasediments (figure 7).
Outcrops in the field to the west of the road. Ask permission at the Theron Stacey farm (west side of the road, first farm to the north across the creek). Park on the side of the road, and walk through the gate. Walk a short distance into the field along the farm track, and then proceed approximately 135' south to the first knoll.
This locality lies along the southern edge of a narrow, curved inlier of metasedimentary rock that gives the Canton body its famous "double fish hook" appearance. The inlier dips shallowly southwest beneath the west-southwest to west-plunging tip of the Canton body (figures 1 and 7).
At this stop, we will examine the garnet-sillimanite gneiss that commonly (but not ubiquitously) occurs at or near the margins of the Hyde School Gneiss bodies. Similar garnet-sillimanite gneiss borders inliers of metasedimentary rock within both the Payne Lake and Dodds Creek bodies.
The small outcrop approximately 135' south of the farm track displays well-lineated porphyroblastic garnet-sillimanite gneiss. Lineations plunge approximately 25, S75W, parallel to quartz ribbon lineations in adjacent mylonitic HSG.
Walk 40' farther south to a small knoll consisting of HSG south of the contact. This outcrop nicely displays a characteristic feature of well-lineated and sheared HSG. Many outcrops of HSG are better lineated than they are foliated, and the appearance of the HSG varies considerably with the orientation of the outcrop surface. Surfaces oriented parallel or nearly parallel to the stretching lineation typically appear streaky and "well foliated". Surfaces oriented perpendicular or nearly perpendicular to the stretching lineation typically appear "poorly foliated" or even massive. This results, of course, from the fact that much of the "foliated" appearance arises from the lineation. Some exposures of HSG are essentially L-tectonites (lineation but no foliation, like a bundle of pencils); in such exposures, the foliation is impossible to locate on surfaces oriented perpendicular to the lineation. Understanding the variation in appearance with orientation can be very useful in outcrops where glacial erosion has sculpted rounded knobs and where there are no foliation surfaces to examine for stretching lineation orientation. Studying the outcrop for the "streakiest" surfaces can give a clue to the approximate stretching direction.
This locality exhibits other interesting features that we will not have time to examine during this trip. Roughly 800' northwest along strike from the knoll where we examined the HSG, dip slopes on the main foliation (Sm) have prominent southwest-plunging corrugations 0.5-1.0 m in wavelength. Examination of west-facing outcrop surfaces reveals that these corrugations are erosional features marking the intersection of slightly less resistant HSG with slight more resistant shear zones 1-2 cm thick. The shear zones dip steeply west at a high angle to Sm. The shear zones have a prominent mylonitic fabric and a component of down-to-the-west slip. As in the Payne Lake, Dodds Creek, and Beaver Creek gneisses, younger shear fabrics such as these attest to prolonged and complex ductile shear in the Lowlands.

Crossing the Little Race Track.
The stream valley marks the location of a weakly resistant, curved "finger" of metasedimentary rock that gives the Canton body its well known double fish hook map pattern (figure 1).

First outcrops of HSG in the North Pyrites body.

STOP 8. Low outcrops on the right side of the road.
Spectacularly lineated Hyde School Gneiss of the North Pyrites body (figure 7).
This outcrop displays fabulously lineated Hyde School Gneiss near the northern margin of the North Pyrites body. Quartz ribbons in this outcrop are many centimeters long and plunge shallowly northwest (approximately 10, N60W). The foliation carrying the lineation dips shallowly north (N89W, 18NE).
The power pole at the east end of the outcrop is rip-rapped with locally derived lineated HSG containing mafic tongues highly elongate parallel to the stretching lineation. The origin of these tongues is not clear at this outcrop. In a spectacular series of outcrops in the yard and gardens of the house across the road and to the west, however, features clearly show that the mafic material occurred originally in layers and has since been isoclinally folded and disrupted by shear. The tongues may very well have sheath-shaped geometries, although this is difficult to prove in these glacially-polished outcrops. We will not visit this locality during the field trip, because the gardens could easily be trampled. The owners, the French's, have been kind enough to give individuals permission to view the outcrops and could be approached for permission if a group is very small.
Unlike the annealed fabrics in rocks of the Canton body, fabrics in many samples from the North Pyrites body are recovered but not annealed. In addition, fabrics in some samples from the North Pyrites body are spectacularly un-recovered and display highly strained porphyroclasts and serrated grain boundaries, suggesting, once again, a complex and protracted shear history in the Lowlands.

STOP 9. Outcrops to the south of the road
Outcrops to the south of the road between the road and the woods.
Discordant shear fabric in the Hyde School Gneiss along the eastern margin of the North Pyrites body (figure 7).
This exposure of lineated and foliated Hyde School Gneiss lies along the eastern margin of the North Pyrites body. Unlike the HSG at stop 8, the HSG at this locality displays well-developed compositional layering oriented approximately N20W, 7OSW. The prominent lineation in the outcrop does not, however, lie in the plane of the compositional layering. Rather, the lineation is carried in a foliation that dips shallowly northwest, discordant to the compositional layering. This discordant foliation has the same kinds of distinctive asymmetric structures characteristic of shear fabrics that can be seen in the HSG of the Payne Lake, Dodds Creek, and Canton bodies, and we have termed this discordant foliation Sd. The lineation at this locality plunges approximately 20, N50W.
The orientations of Sd and the associated lineation Ld vary somewhat across the North Pyrites body, but Ld generally plunges shallowly NW. Shear sense determined from preliminary examination of thin sections appears to be top side down to the northwest.
Based on both the shape of the North Pyrites body and on the presence of prominent shear fabrics, we tentatively suggest that the North Pyrites body is a sheath fold plunging shallowly northwest (figure 1). We would interpret the lineated foliation, Sd, in much the same way as we have interpreted the discordant foliation in the Payne Lake body, as an axial plane foliation that developed parallel to the sheath fold axial surface as the sheath fold grew in a major shear zone. Where the earlier fabric, Sm, lies at a high angle to the axial plane of the sheath, as it does at this locality, Sd is clearly discordant to Sm and to compositional layering.

B1: BEDROCK EROSIONAL FORMS PRODUCED BY GLACIAL PROCESSES, NO.2 MINE, GOUVERNEUR TALC CO., GOUVERNEUR, NEW YORK.
DONALD L. PAIR
University of Dayton
JAMES S. STREET
Canton, NY, 13617
FRED R. TOTTEN and JOHN E. KREIDER
Gouverneur Talc Co.
Gouverneur, NY, 13642
This trip takes place at the No. 2 (Arnold) open pit mine of the Gouverneur Talc Co. NYSGA last visited this location in 1971 on a trip led by J.S. Street (St. Lawrence University). He described a number of highly polished grooves, flutes, crescentic fractures, and striations present on bare bedrock surfaces (Street, 1971). Stops on this field trip will focus on the geologic setting of the region, history of pit operations, and a re-examination of the intriguing erosional forms present on both horizontal and vertical exposed bedrock surfaces. Our discussion will center on the nature and classification of these erosional forms, field evidence suggesting their possible origin, relationship to regional ice flow patterns, and their possible implications regarding subglacial processes and conditions.

B1: BEDROCK EROSIONAL FORMS PRODUCED BY GLACIAL PROCESSES, NO.2 MINE, GOUVERNEUR TALC CO., GOUVERNEUR, NEW YORK.

STOP 1. North end of pit
At this stop mine geologists will discuss the tectonic framework of the Northwest Adirondack Lowlands, provide a overview of the mineralogy and stratigraphy at the pit, and summarize the history of mining operations.
2015: Mine closed in 2008. Considerable reclamation since then. GE has good image from 1997.

STOP 2: South end of pit.
NOTE: Please stay off the bedrock faces directly above the open pit. Beware of slippery footing on the vertical face. Many of the forms are best viewed from the road!
At this stop we will examine the bedrock erosional forms present on both horizontal and vertical surfaces at this end of the No. 2 Mine. Discussion will focus on the regional glacial setting, proposed classification of the forms, the possible origin of these intriguing forms.
Possible questions for discussion:
1. Do differences in the bedrock lithology control the location and distribution of the various bedrock erosional forms?
2. Can embedded 'tools' frozen in the ice abrade with smooth, sharp surfaces and produce all of the erosional forms present?
3. What do these forms say about the plastic nature of glacial ice at several scales?
4. What is the significance of these erosional forms occurring on the sides of the linear, rock-walled valley that includes the No. 2 Mine?
2015: Mine closed in 2008. Considerable reclamation since then. GE has good image from 1997.

STOP 3: Pulpit Rock.
Discussion at this stop will address the possible origin of the well known Pulpit Rock.

Linear, rock-walled valley
We are in the bottom of another of the linear, rock-walled valleys common to this region.

B2: THE POTSDAM-GRENVILLE CONTACT REVISITED (II)
JOHN BURSNALL
Canton, NY 13617
BILL ELBERTY
Department of Geography
This field trip continues the review, initiated in Trip A2 (Bursnall and Elberty, this volume), of outliers and enclaves of younger arenaceous rocks in contact with Grenvillian gneissic basement. The trip will concentrate on relationships between this basement and cover rocks, or enclaves, in the Dekalb and Richville areas whose affinity with the Upper Cambrian (?) Potsdam Sandstone is equivocal.
Repeats of Stop 7 and 8 of Trip A2 (described below) provide a basis for the trip, which includes an investigation of a newly exposed section in Dekalb (Stop 3). This exhibits somewhat similar relationships to those seen at the Rock Island roadcut (A2, Stop 6) which have been proposed as originating from burial of a karst topography - specifically the infill of solution pockets in marble on the Precambrian erosion surface (Carl and Van Diver, 1971). Outcrops of quartz arenite, "metaquarzite", and conglomerate to the south of Dekalb which were seen by Bloomer (1965, 1967) as being inseparable from the surrounding Grenville will also be visited. These, or very similar lithologies are contained as clasts in some of the sandstones (e.g., Stop 8, A2 and Stop 3, this trip).
"The Potsdam-Grenville contact in the St. Lawrence valley represents a hiatus of some 500 Ma. Mineral assemblages within the Grenville gneisses indicate that perhaps 25 km of material was eroded prior to the deposition of the transgressive Cambro-Ordovician sequence, over an undulating Precambrian erosion surface. Many of the isolated, predominantly sandstone, bodies within the Grenville gneiss terrane of the Adirondack Lowlands can be confidently interpreted as outliers of Potsdam Sandstone. ........ Such enclaves vary in composition from matrix supported breccias to equigranular orthoquartzites and their depositional environment has been variously interpreted as: pre-Potsdam solution pocket infills (related to a karst topography on a Grenville marble surface); fault related debris slides; fault breccias; and fault scarp talus accumulations. Some are seemingly crudely interlayered with the gneisses and are locally foliated" (Bursnall and Elberty, this volume).
The age of these enigmatic rocks have variously been proposed as:
1) outliers of Potsdam Sandstone
2) pre-Potsdam, post-Grenville remnants
3) Grenville in age, in that they suffered at least the later stages of Grenvillian deformation

B2: THE POTSDAM-GRENVILLE CONTACT REVISITED (II)

STOP 1: East Dekalb (Stop 8, Figure 1)
For convenience, the following description is taken from Trip A2 of this volume.
"Roadcuts due south of Dekalb further illustrate the complexities within these post-Grenville rocks. A long series of low exposures on the northwest side of the road contain well-layered marble (reclined folds at the north end) to the north which in the central section give way to a complex steep contact with rusty weathered arenaceous rocks. A number of small sandstone breccia wedges penetrate downwards into the marble in the vicinity, again supporting the solution-pocket infill model for the larger scale relationships seen elsewhere (e.g. Rock Island Road). Evidence for sulfide mineralization is present at some contacts, in common with the Rock Island Road locality (Elberty and Romey, 1990).
Bedding in the sandstone is irregular and breccia/conglomerates are common, particularly lower in the section a hundred yards to the south and at the base of the southernmost outcrop on the northwest side of the road. A poorly defined cylindrical structure exists in the latter section and may be seen on the top of a low outcrop of compact, rusty weathered, quartz arenite (compare with Stop 3).
Similar conglomerate and breccia occur in a large outcrop on the southeast side of Route 11. Quartz, quartz-arenite, and metaquartzite are common clast compositions and are similar to those at Stop B3 (Stop 9 in Fig. 1). In both the western and southeastern outcrops shaly zones could have been generated by shear and at the northern end of the latter bedding dips are steep (>60°; Karboski, 1977), yet again supporting the notion of significant post-depositional deformation." (Bursnall and Elberty, this volume).

STOP 2. The Richville breccias (Stop 7, Figure 1)
Please note that description for this stop is taken from Trip A2, this volume
"Karboski et al. (1983) described this outcrop this as containing a "flow breccia" at its base, followed by a densely consolidated breccia with an overlying highly deformed metaquartzite, overlain by an "orthoquartzite", which contains pebble-sized quartz clasts - possibly derived from the underlying metaquartzite. The breccias contain quartz clasts set in a hematite stained, medium grained arenite. Large (0.5 m) phacoidal blocks of the breccia are enveloped by thin shaly borders, the whole giving the impression of a shear zone.
This outcrop certainly inhibits any notion that the unconformity between Precambrian basement and overlying cover is a simple one!
Points to concentrate on are:
1) Possible shear fabrics in the lower part of the outcrop, in part defining the borders of coherent blocks of breccia
2) Compositional variation of clasts in the breccias
3) The relationship between and the textural character of the each of the recognized rock types
If the upper part of this outcrop is indeed comprised of rocks which are part of the Grenville basement as supposed by Karboski (1976) and Karboski et al. (1983) then the current disposition of lithologies seems not to be satisfied by a model that involves karst infill alone (Van Diver, 1976) as seems possible at Rock Island Road. It is possible, however, that the wall collapse of a large solution depression may have allowed a slab of basement to slide into the argillite filled basin. The presence of shear fabrics within the breccia may be accommodated by this model provided that these rocks were only partially lithified at the time.
Cross over to the vehicle and investigate the southern end of the outcrop on the southeast side of the road. Here, a narrow zone of sandstone breccia dips steeply through marble. One of the contacts is sheared indicating high angle faulting. Is there evidence for displacement sense?
[Note: if time permits an outcrop of marble on the northwest side of Route 11, a few hundred yards to the south should be visited. It contains narrow subvertical veinlets of arenite at the northeast end, which provide good evidence for solution cavity infill.] " (Bursnall and Elberty, this volume).

STOP 3. Large outcrop on the west side of the road
Large outcrop on the west side of the road at the entrance to Dekalb (gentle left-hand bend)
Note: the best parking is approximately 100 yards to the south along a disused section of Route 812, opposite an Amish farm.
STOP 3. (Stop 9 in Figure I)
This outcrop possesses a newly exposed surface resulting from road-widening and contains a number of irregular sandstone bodies within well-layered Grenvillian marble.
A number of sub-vertical arenaceous zones, varying in width from less than one to greater than ten feet in width occur throughout the outcrop. In the largest of these fragmentation and "stoping" of the marble wall rock is evident but relatively few areas exhibit "permissive veining" relationships - where separated marble fragments could be pieced together in their pre-fragmentation configuration. In places, it is possible that injection of sand could have occurred from below. In addition to marble, abundant angular quartz arenite fragments similar to the foliated quartzite of Stop 4 are present.

STOP 4. Deformed quartz arenites of possible Grenville age
Where this road curves sharply to the left, continue and park on the right. Stop 4 is in the woods on the right (west).
STOP 4. Deformed quartz arenites of possible Grenville age (Stop 10 on Figure 1). Outcrops of conglomerate and foliated quartz arenite occur 75 yards into the woods (stay close to an old fence on the left until these outcrops are visible). These rocks were thought by Bloomer (1965, 1967) to belong to an infolded sequence within the Precambrian gneisses and to have been affected by probably the latest stages of Grenvillian deformation. Foliated and folded metaquartzite (best seen on the top of the ridge) is petrographically very similar to clasts at the previous stop and at Stop 1. Fold style here, however, and the nature of the conglomerate (at the base of this outcrop), suggests that these rocks may not have experienced the full Grenvillian deformation sequence but could represent a post-Grenville, pre-Potsdam, depositional period.

It includes a quarry on the east side of the road

STOP 5. et seq. (Stop 11 on Figure 1)
The section referred to above extends from the northern part of Dekalb village to the Oswegatchie bridge near Kendrew Corners (at 3.25 miles from the junction of Routes 812 and 17). It includes a quarry on the east side of the road (at 0.8 mi.) and conglomerates exposed on the Oswegatchie River at Coopers Falls (at 1.3 mi.). To reach the falls ask permission at the house opposite the intersection of the Old Canton Road and follow the track that passes the house to the south. For additional description of a part of this section see Trip A3, Stop 2 in this volume.

B3: SEDIMENTOLOGY AND DIAGENESIS OF THE POTSDAM SANDSTONE AND THERESA FORMATION, SOUTHWESTERN ST. LAWRENCE VALLEY
BRUCE W. SELLECK
The lower Paleozoic strata in the southwestern St. Lawrence Valley consist of the Late Cambrian-Early Ordovician Potsdam Sandstone, Theresa Formation and Odgensburg Dolostone. This sequence totals approximately 120 meters in thickness, and is the age equivalent of the considerably thicker passive margin carbonate sequence of eastern New York and western Vermont. In the area of this field trip, the lower Paleozoic sequence is well-exposed along the St. Lawrence River from the vicinity of Ogdensburg to Alexandria Bay, New York. In this area glacial sedimentary cover is thin or absent, and outcrop exposures are common in streams tributary to the St. Lawrence, and as roadcuts. The contact between the basal Potsdam Sandstone and the Late Proterozoic metamorphic and igneous rocks of the Grenville province is well-exposed in the area. The so-called Frontenac Axis is a topographic high in the Grenville rocks, and trends NNW-SSE. Regionally, Paleozoic strata dip gently to the ENE to the east of the Frontenac Axis and to the WSW to the west. The Medial Ordovician Black River Group overlies the Theresa Formation to the southwest of the area of this field trip. To the north and east Early Medial Ordovician Chazy Group strata overlie the Ogdensburg Dolostone and its equivalents.

B3: SEDIMENTOLOGY AND DIAGENESIS OF THE POTSDAM SANDSTONE AND THERESA FORMATION, SOUTHWESTERN ST. LAWRENCE VALLEY

STOP 1. Upper portion of the Theresa Formation.
Roadcuts on both sides of Route 37 expose tidal flat facies of the upper portion of the Theresa Formation. The basal beds here consist of sandy dolostone with irregular voids containing authigenic dolomite, calcite, quartz, barite and sulfides. Other lithofacies present here include laminated silty dolostones, burrowed dolomitic sandstones and cross-laminated sandstones exhibiting well-developed bipolar cross-sets.

STOP 2. Middle portion of the Theresa Formation
The roadcuts at this stop expose the middle portion of the Theresa Formation. The rhythmic interbedding of yellow-white cross-laminated sandstones and darker, burrowed dolomitic sandstones is typical of this portion of the Theresa Formation. The burrowed units are often capped by a few centimeters oflaminated dolostone. The cross-laminated sandstones are interpreted as low tidal flat deposits, the burrowed dolomitic sandstones as upper intertidal, capped by algal-stromatolitic carbonate mud. These sequences are tidal flat cycles, and their origin may reflect both high-order sealevel change and tidal flat progradation that produced slight but sudden deepening followed by shallowing due to progradation.
Note the apparent soft-sediment deformation represented by the intraformational folds near the northeast end of the outcrops. Note also the more general low-amplitude folding and the high-angle faults.

STOP 3. Contact between Potsdam and Theresa fms.
The contact between the uppermost Potsdam Sandstone and basal Theresa Formation is exposed on the south side of Route 12 near the southwest end of the outcrop. The contact is marked by the change in color (potsdam = white-grey-yellow; Theresa = grey-brown), the abrupt increase in carbonate content in the basal Theresa Formation, and the change in bedding thickness from the thick to massive beds of the Potsdam to the thin beds of the basal Theresa. The lower Theresa in this area consist of2-10 cm. beds of plane-laminated or ripple cross-laminated fine sandstones/siltstones that are capped by calcareous and dolomitic fine sandstones/siltstones. Escape burrows that traverse the laminated beds record attempts of organisms to return to the sediment surface following a sudden influx of sediment. The environment of the lower Theresa is interpreted as a subtidal, near wave base shelf lagoon setting characterized by sporadic sediment influx and physical disturbance of the bottom (storms). These events produced laminated and cross-laminated sheets of sand and silt, the tops of which were subsequently colonized by organisms, producing the bioturbated tops on each bed.
The upper Potsdam Sandstone at this stop consists of burrowed calcareous sandstones and laminated and cross-laminated sandstones that generally resemble the middle portion of the Theresa Formation seen at the last stop. The trace fossil Diplocraterion is common in the burrowed units, and a alternating low tidal flat - high tidal flat environment is envision for these facies. Fragments of the brachiopod Lingulepis are common in the upper Potsdam and lower Theresa at this stop. The lower Theresa here also contains scattered pebbles and cobbles of quartzite that were clearly derived from a Proterozoic basement knob exposed approximately 300 meters south of this outcrop.

STOP 3a. Replicates last stop
This stop replicates the sequence observed at our last stop, and we will only stay a short time to examine the features of the upper Potsdam Sandstone, which are somewhat better exposed here. Very well-preserved examples of Diplocraterion are present in the upper Potsdam on the southeast side of the outcrop.
Note the outcrop of Proterozoic basement immediately to the southwest along Route 12.

STOP 4. Contact between lower and upper Potsdam Sandstone
The contact between the lower and upper portions of the Potsdam Sandstone is exposed in the roadcut on the southwest side of Route 12. The lower section of the outcrop consists of medium-bedded, cross-laminated, medium-grained sandstones typical of the lower Potsdam. The upper, massive calcareous sandstone bed is highly burrowed, and is the base of the upper Potsdam. This facies of the lower Potsdam is interpreted as a shallow, wave and tidal current dominated shelf.
The contact between the lower and upper Potsdam represents a depositional hiatus of some duration. Networks of vertically-oriented cracks, brecciated sandstone and kaolinite-cemented concretions are common along this horizon, which is widely traceable throughout the St. Lawrence Lowlands, and clearly represents a sea level lowstand. As noted in the text, the lower Potsdam may be Dresbachian, based upon the occurrence of Climactichnites, whereas the upper Potsdam is Tremadocian, suggesting that a portion of the upper Cambrian is absent due to non-deposition, or erosion, prior to deposition of the upper Potsdam.

STOP 5. Proterozoic/Potsdam unconformity
The unconformity between the basal Potsdam Sandstone and underlying Proterozoic gneisses is exposed in the roadcut on the southeast side of Route 12. The time interval represented by this contact is some 600 million years. The basal sandstones here exhibit large-scale low-angle planar-tabular cross-bedding, and are devoid of fossils. The depositional setting for this facies is problematic, although shallow marine tidal inlet, shoreface, and perhaps even aeolian dune environments are possible facies models.
Considerable variation in color pattern is evident in the lower Potsdam here, with the basal meter or so consisting of white to light grey sandstone, and the remainder of the outcrop showing pink, red, orange and salmon colors often seen in the Potsdam used as building stone. The colors here are due to finely crystalline hematite, goethite and anatase (=leucoxene) which form pigments around the detrital grains and within secondary quartz and illite cements. The iron and titanium for these pigments were derived from the breakdown of detrital magnetite and ilmenite grains in the original sediment. Paleomagnetic studies at this outcrop suggest that the iron-bearing minerals were precipitated in late Paleozoic time. The white sandstones at the base of the Potsdam contain no hematite or anatase, although limonite-goethite halos of relatively recent origin are developed around some magnetite grains.
Note the alteration of the underlying gneisses immediately beneath the Potsdam. The alteration assemblage here consists of illite, Fe-chlorite (or berthierine), siderite and quartz.

STOP 6. Typical lower Potsdam Sandstone
The roadcut on the southeast side of Route 12 exposes typical lower Potsdam Sandstone. Plane-bedded medium- and fine-grained sandstones underlie and overlie a one meter thick bed of cross-bedded medium sandstone. The dominant cross-bed dip direction is SSW. Above the thick cross-bedded unit small-scale cross-strata dip to NNE. As with many exposures of the lower Potsdam, the environment of deposition is difficult to assign, Although the flat-bedded sandstones lack trace or body fossils, a shallow marine environment is suggested by the continuity of individual beds, the lack of upward fining or coarsening trends, and the lack of channel form geometry. However, definitive primary structures are absent. The thick cross-bedded unit was produced by a bedform of perhaps two or three meters in amplitude. Stoss-side erosion beveled the upper portion of the structure as it migrated, leaving behind a scoured lag deposit of granules at the updip termination of the cross-strata. A structure of this size and geometry could be produced by tidal currents or by wind during a period of emergence.

STOP 7. Proterozoic/Potsdam unconformity
The unconformity between the basal Potsdam Sandstone and Proterozoic gneisses is again exposed in these large roadcuts on both sides of Route 12. The dominant facies here is typical of the lower portion of the Potsdam, Flat-stratified medium- and fine-grained sandstones are interrupted by 0.2 to 1.0 meter thick sets of cross-strata, The lack of trace and body fossils again makes assignment of a depositional environment somewhat difficult.
Note the altered gneiss immediately beneath the contact. illite, Fe-chlorite, and siderite form the alteration assemblage. The sandstones immediately above the contact contain abundant authigenic illite, which has been K-Ar dated at 355-360 million years.

STOP 8. Conglomerates in the Potsdam formation
These long roadcuts on Interstate Route 81 expose a sequence of conglomerates and pebble-cobble sandstones in the Potsdam Sandstone. The quartzite cobbles in these exposures were derived from a basement quartzite ridge immediately to the south. At least some of the conglomerate beds here were emplaced by mass flow mechanisms, perhaps as sandy debris flows. Wave reworking of the tops of mass flow beds indicates that the sands and gravel were deposited in a marine setting. Near the top of the exposure the contact between the lower and upper Potsdam is present, and burrowed calcareous sandstones succeed the conglomeratic facies.

B4: SOME CLASSIC MINERAL COLLECTING SITES IN ST. LAWRENCE COUNTY
MICHAEL A. WHITTON
St. Lawrence County Rock and Mineral Club/
Canton, NY 13617
SCHUYLER ALVERSON
St. Lawrence County Rock and Mineral Club
P. O. Box 112
Rensselaer Falls, NY 13680
The St. Lawrence County Rock and Mineral Club is a local organization who meets once a month and organizes collecting field trips as well as trips to rock and mineral shows. We have members from as far away as New Hampshire, Ohio and Canada. All meetings and trips are open to the public. It is our pleasure to welcome you to Canton and to lead you on this field trip of classic mineral localities in St. Lawrence County.
If you would like more information about our club for attending some of our meetings or trips, you may write to our club president Gary Stacy, 148 Rowley St., Gouverneur, NY 13642, vice-president Michael Whitton, 24 Miner St., Apt. 1, Canton, NY 13617, or Schuyler Alverson at the above address. Michael will be along on this trip as one of the principal guides. He will be happy to take a business card or take down your name and address to include you in the club's next newsletter.
We will be departing Canton, from St. Lawrence University at 8:30 AM on Sunday, September 26. Our first stop will be at Benson Mines in Star Lake. At one time, this was the largest open pit magnetite mine in the world. Our second stop will be in West Pierrepont at a tremolite locality. Our last stop will be the world famous Powers' Tourmaline Locality in Pierrepont. This site has been known for over 100 years since George Kunz wrote about it in 1892. We will learn more about each stop later. At the end of this road log will be a list of suggested readings for these stops if you would like to find more information about them.
We will be eating en route to our second stop to save time. We will spend a good deal of the morning traveling to Star Lake and back. You may eat at any time you wish, but we want to be sure to have everyone back to Canton on time so that they will not miss their rides or their scheduled time of departure. The map on the next to last page of this trip log shows our route and the stop locations.

B4: SOME CLASSIC MINERAL COLLECTING SITES IN ST. LAWRENCE COUNTY
Michael A. Whitton and Schuyler Alverson

Climb up Waterman Hill toward Degrasse.
There will be a radio tower in a field on the right on top of the hill. Notice the vista over Canton behind you.
Michael A. Whitton and Schuyler Alverson

This intersection is known as the Turnpike Crossing.
If you'll notice the tavern on the corner you will understand why.
Michael A. Whitton and Schuyler Alverson

STOP 1. J & L STEEL CORP. BENSON MINES. STAR LAKE. NY
History of the Mines The ores were first discovered in 1812 when a military road was being built in the region. It became known as the Chaumont Ore Bed. In 1883 the Magnetic Iron Ore Co. was formed. Byron D. Benson, a large land owner in southern St. Lawrence County sells the company the mineral rights on 2,201 acres of the Brodie Tract in the town of Pitcairn. In 1886, a railroad is started from Carthage to Jayville in the town of Pitcairn and additional mineral rights on 40,000 acres in the southern part of the county are obtained by the Magnetic Iron Ore Co.
In 1887 and 1888, the company purchased minerals rights for magnetite iron ore on Vrooman Ridge in the Town of Fine and all the mineral rights (9,185 acres) in the southeast comer of Chaumont Township (later part of Clifton Township) including the Chaumont Ore Bed. In 1888-89, work was done on the Jayville mines in the town of Pitcairn. From 1889-93 the Magnetic Iron Ore Co. shipped 150,000 tons of high grade concentrates (magnetite iron ore) to Pennsylvania.
In 1906, Benson Mines Company formed and leased Benson Mines (Chaumont Ore Bed). From 1907-1919, sporadic mining occurred at Benson Mines and in 1922 the Benson Mines Co. gave up its lease and sold its plant to the Magnetic Iron Ore Co., owner of the mineral rights.
Later in 1922, the Benson Iron Co. Inc. was formed, but did not do much mining. In 1941, Jone & Laughlin Ore Co. leased Benson Mines and built a $7,000,000 mill and upgrade of the mine. In 1946, the Benson Iron Co. Inc. and Magnetic Iron Ore Co. (both belonged to the Benson family) consolidated to form the Benson Iron Ore Corporation, and by 1950, it was the largest open pit magnetite iron ore mine in the world.
In 1978 Benson Mines shut down. The St. Lawrence County Development Corporation tried to find a buyer or lessee without success. Lumbering is the only thing going on in the mine area now that is bringing in any money, but just barely enough to pay the taxes. Of the 3,200 acres now owned by the company, only 1,200 are cut in a 15 year cycle to that allows for replenishment. There is some sale of waste rock, but the income from this is negligible. The mine used to employ 1,000 people and pump 2,000,000 gallons of water a day .
Geology The Benson Mines ore body is not of simple origin. Sillimanite gneiss, metagabbro and pegmatitic units are located throughout the pits. Small, localized fault zones rich in secondary mineralization provide the areas of greatest interest to the crystal collector.
Minerals The primary ores mined here are magnetite and martite. Samples of each abound. The sillimanite crystals from here are unparalleled in their size. The sunstone, relatively common in the pegmatitic zones, may be fashioned into cabochon and used to make attractive jewelry. Probably the most desired species from this mine is the dark green fluorite cubes, found about 30 years ago in a fracture zone and associated with various other secondary minerals. These, needless to say, are only rarely found. The following minerals can usually be collected, many in crystal form: aragonite, azurite, bornite, calcite, chalcopyrite, chlorite, garnet, hematite, hornblende, magnetite, malachite, martite, microcline, molybdenite, muscovite, pyrite, quartz, sillimanite, sunstone, tourmaline, and others.
The tools that will be most helpful here are a crack hammer, chisel and small pick. Be sure to bring something (sample bags, boxes) to store your specimens in on the trip . Collecting is by clubs or groups only. Permission may be obtained and arrangements made by writing in advance. The person to talk to, his address and phone numbers are listed here. He will send you a release form for everyone to sign and return before going to the mine. Please respect the common courtesies expected of you.
David H. Ackerman
Benson Mines, Inc.
100 Bay Street
Glens Falls, New York 12801

STOP 2. TREMOLITE LOCALITY. WEST PIERREPONT. NY
History of the Site This site has also been known for many years. It was discovered by prospectors looking for iron ore. Ours was one of the first rock and mineral clubs to visit the site in 1965; Originally, the amphiboles were called actinolite. However, Dr. George Robinson identified them as tremolite by electron probe.
Geology Tremolite-actinolite crystals are commonly found in the calcium silicate rocks associated with the county's Grenville Marble deposits. The rock here appears to be a tremolite-quartz schist, with varying amounts of calcite, diopside and pyrite. A large body of leucogranitic rock nearby, if representing an igneous intrusion, may have provided the necessary physiochemical conditions to recrystallize the adjacent sediments.
Minerals Doubly terminated crystals of tremolite-actinolite occur in pockets and fissures throughout the outcrop. Other nearby outcrops have furnished dravite, diopside, pyrite and quartz crystals.
Notes The best crystals are in the cracks and crevasses in the ledges. Hammers, chisels, crowbar and small digging utensils will prove useful.

STOP 3. POWERS' FARM. PIERREPONT. NY
The collecting site is just a short hike along the brook. Stay on the farm lane until you come to a path. Turn left onto the path and twenty-five yards or so ahead is the collecting area.
History of the Site As stated above, George Kunz wrote about this locality in 1892. It was known to collectors for some years before that. It was originally the Ryland Clary Farm. An aggressive mineral collector by the name of Charles D. Nims would drive his horse and wagon to the site from Canton where he worked for the railroad for 10 years. He would remove baskets full of crystals.
Around 1910, Bower Powers, Sr. bought the land. In 1921, William Agar wrote about the occurrence. Just prior to 1962 the top of the hill had been bulldozed. In 1993, due to littering, people sneaking in, burning fires and digging on the hillside next to the stream, Bower Powers, Jr. closed the site to individuals. It is still possible to arrange in advance club or group trips as long as you abide by the rules. There are still many nice crystals to be found.
Geology The geology of this PreCambrian Grenville site is very complex. The interesting minerals occur in veins and along contacts between the Grenville marble and other metamorphic rocks including a mica-tourmaline-quartz schist, an amphibolite, and other rocks locally rich in pyroxene or scapolite. Additional evidence of an origin through recrystallization is provided by the frequent presence of uralite, a pseudomorph of actinolite after diopside. The field relationships are buried by overburden . The mineral paragenesis is complicated and not worked out.
Minerals The uvite tourmaline crystals found here are indeed world famous. They contain a relatively high percentage of iron. These dark, magnesian tourmalines are typified by their lack of prismatic striations and short c axes. Figure 1 below illustrates the most commonly encountered forms: trigonal prism (m), ditrigonal prism (a), rhombohedra (e) and (r), basal pedion (c), and trigonal pyramids (0). Other minerals to be found here in excellent representations include: uralite, rennselaerite, diopside, pyrite, pyrrhotite, quartz, apatite, micas, chlorite, calcite, actinolite, titanite and scapolite.
Notes Although small single crystals may be found in the soil, the better specimens lie deeper and occur most often in pockets and seams in the solid tourmaline-quartz rock, especially where it is in contact with the calcite. Often, good specimens can be obtained by removing the calcite from the matrix rock with dilute hydrochloric acid.
Useful tools for this location include shovels, crowbars, sledge hammers, wedges, and other heavy tools will be needed to reach the deeper crystal bearing areas, but hand tools will also be useful.

Edited by:
Carlton E. Brett, University of Rochester
James Scatterday, SUNY Geneseo
Technical Consultants:
Mary Nardi
York, New York
Richard D. Hamell
The Genesee Valley is a classic region for the study of sedimentary geology. The Genesee gorges at Rochester and Letchworth were explored geologically by many of the great early American geologists, particularly James Hall. Herman Leroy Fairchild, an early professor of Geology at the University of Rochester, and a founder of the Geological Society of America, made a career of studying the Genesee Valley glacial history.
The Genesee Valley area features an excellent cross-section of mid Paleozoic sedimentary rocks, ranging in age from the Late Ordovician to the Late Devonian. Upper Ordovician Queenston redbeds and overlying Lower to Middle Silurian mixed carbonates, shales, and sandstones, including the well known Clinton hematite, are exposed in the heart of Rochester itself. To the south are exposures of Late Silurian evaporites, shales and eurypterid-bearing dolostones, succeeded by fossiliferous beds of the Middle Devonian Onondaga Limestone. Still younger black and dark gray, exceptionally fossiliferous shales of the Middle Devonian Hamilton Group are exposed in tributaries of the Genesee River south of the Thruway. Outstanding exposures of Upper Devonian shales and siltstones of the "Portage" facies crop out in the spectacular cliffs of the Genesee River gorge at Letchworth Park, "the Grand Canyon of the East". Many of the outcrops in the Genesee area and the immediate vicinity are extraordinarily fossiliferous, and the strata themselves have been subject to substantial reinterpretation in the light of event and sequence stratigraphy, taphofacies, and models of foreland basin dynamics.
The Genesee region is an outstanding area for the study of surficial and glacial geology. The Genesee Valley was occupied by an extraordinary sequence of proglacial and moraine dammed lakes. Classic examples of eskers, kames, kettles and drumlins can be viewed in areas such as Mendon Ponds Park and also in the Pinnacle Hills moraine within the city of Rochester itself. Within the past decade, Pleistocene sand and marl deposits in the Genesee Valley region have yielded two exquisite mastodon skeletons, as well as other vertebrate and invertebrate fossils. The basic outlines of the complex Pleistocene geologic history of the Genesee Valley were established by Fairchild. However, renewed interest in surficial deposits, together with radiocarbon dating, has yielded a modified picture in the past several decades.
The Rochester area is also an ideal region for the study of urban geology and environmental hazards and problems. These include the highly publicized problem of roof collapse of the Akzo salt mine, landslides and slumps within Pleistocene sediments around the Irondequoit Bay region, problems of river erosion and flood control, including spectacular examples of migrating meander loops in the modern Genesee River, and the development of hazardous waste dumps in several places in the region.
This guidebook provides updated synthesis of several of these aspects of regional geology in the Genesee area. Bedrock geology of the Upper Ordovician to Upper Devonian is covered in a series of papers. Three other articles provide new syntheses and insights into aspects of surficial geology and environmental geology. Inevitably, there are gaps. There is no paper on the Salina Group, for example, which is unfortunate given recent interest in salt mining! Also, no tectonic or petrologic studies are included. However, on the whole, I believe that the guidebook presents a reasonable cross-section of Genesee Valley geology.
On a personal note, I cannot help but reflect that the first New York State Geological Association meeting that I attended as a student was held over twenty years ago in 1973, the last time NYSGA met in the Rochester area. (In fact, it was actually hosted by SUNY at Brockport.) It was on that occasion, while I was camped at Hamlin Beach State Park with some other students, that my friend, Gerry Kloc, came running back from the Saturday evening banquet full of excitement about a unique individual, named Gordon Baird, who knew about the geology of Erie County and other parts of New York State. I said "No way; nobody else really works on this stuff!" Nonetheless, the next day, accompanied by my fiancee (now wife), Betty Lou Hilton, I went to Old Dewey Hall at the University of Rochester to meet with this "Wunderkind". Sure enough, Gordon did know about Penn Dixie quarry, the North Evans conodont bed, and a great deal more that I thought that I had discovered. We had been working on the same stratigraphic sections for over five years without crossing paths. I was, of course, greatly impressed by Gordon's extensive collections of weird and wonderful geological specimens. More than that, I was struck by his incredible store of knowledge, wit and enthusiasm. Here, was a kindred spirit. Under other circumstances, Gordon and I could have become bitter rivals, like Cope and Marsh. That was not to be, however, for we both preferred cooperation to competition. From that September day onward, we became coconspirators in the "plundering of northeastern geology". By the time of the 46th Annual NYSGA, we had worked together enough to collaborate for the very first time in leading a field trip. Ironically, the trip dealt with the Windom Shale, a topic we again address in this guidebook, with considerable updating, some 20 years later. In the meantime, we have jointly studied over 1,000 streams and other outcrops in New York, have made many exciting discoveries, and have had countless conversations on the geology of the northeast during thousands of miles of travel on New York's Thruway and back roads. It has been an exciting ride, and a considerable part of it is logged in NYSGA guides.
I also note that the last time NYSGA officially met at the University of Rochester, in 1956, the guidebook, a thoroughly valuable contribution that was copied numerous times, was in more or less the form of handouts for student geological field trips. Since then, and even since 1974, the guidebooks have grown larger (yes, we have contributed to that), and of increasing quality. The NYSGA Guidebooks over the years, have become an invaluable trove of explicit information about New York's geology, coupled with road logs that enable students and professionals to assess for themselves the ideas presented in articles. These guidebooks present a great deal of information that is unavailable in any other source. I personally feel that the guidebooks have several very significant roles. The first, clearly, is that they are a vehicle for dissemination of often new, sometimes preliminary information. Certainly they continue to have a very critical teaching function. How many of us have at one time or another copied the road logs, figures or texts of NYSGA articles to supplement our class field trips? The articles in a guidebook, such as this one, present information, and more importantly, ideas, about geology, some correct, some perhaps incomplete or incorrect, but available for students in all categories of New York geology. In my view, the articles should present material in a variety of ways. Certain articles are geared for the more general audience, others are available for advanced students and for professionals specializing in particular areas. Another function which has not always been emphasized, but one which we have taken liberal advantage of, is that the guidebooks provide a vehicle for publication of fairly detailed information about regional geology. Where else can such information be published or found by the student interested in local details? Certainly, most of the professional journals, such as Geological Society of America, Journal of Sedimentary Research and others tend to publish articles that are broad, and of general interest, but typically, through editorial dictate, are "cleansed" of detailed outcrop-based information. In that regard, I feel that the NYSGA Guidebooks have a very important role to play as archives for such information.
I would like to express my sincere appreciation to numerous individuals who helped in the organization of this meeting and in the writing, editing and compiling of the present guidebook.
First of all, I owe a debt of gratitude to the authors of the several articles and leaders of the trips. They all came through and worked diligently to produce meaningful and interesting articles. Final preparation of manuscripts and compilation of the guidebook were aided greatly by the secretarial expertise of Susan Todd and Heidi Kimble of the University of Rochester. Mary Nardi, David Lehmann and James Scatterday helped greatly in the editorial process. Numerous reviewers, acknowledged in the individual papers, aided in the improvement of the final product. Dr. William Kelly of the New York State Geological Survey and presently head of the NYSGA, provided strong support and encouragement in the preparations for this meeting. Don Parry and Keith Kurz of the University's Conference Office also helped greatly in organization aspects of the registration and meeting logistics. Finally, several past and present students of the Department of Earth and Environmental Sciences helped in numerous ways to prepare for the meeting. I particularly wish to recognize the efforts of Wendy Taylor, Robyn Hannigan, Chuck Ver Straeten and Gerald Kloc. Richard Hamell of Monroe Community College helped me with design of the cover; we chose a pale purple in recognition of Rochester's lilac traditions. My colleagues in the Department of Earth and Environmental Sciences, especially Curt Teichert and Robert Sutton, have always been supportive and encouraging to me in my various projects, including this one. Gordon Baird has helped me over the past two decades in ways too numerous to mention. Finally, I should acknowledge the patience and support of my family, particularly Dr. Betty Lou Hilton Brett, for without that, none of this would be possible. She cannot say she was not forewarned! You may note that she was with me on that famous first meeting with Gordon Baird; and we were engaged within the same week as that fateful meeting of the NYSGA in the Rochester area in 1973.
The Empire Soils Corporation of Huntington Enterprises, Inc. of Rochester generously provided $200.00 in support of the meeting.
Carlton E. Brett, President
New York State Geological
Association - 1994

A1:THE HYDROGEOLOGY OF LANDFILL SITES IN WESTERN NEW YORK
William M. Goodman
The Sear-Brown Group
85 Metro Park
RONALD B. COLE
Allegheny College
Meadville, Pennsylvania 16335
DAVID F. LEHMANN
Huntingdon Engineering & Environmental, Inc.
535 Summit Point Drive
Henrietta, New York 14467
Because existing state environmental regulations require extensive hydrogeologic reports for landfills, waste disposal sites provide a wealth of penetrative data that may be synthesized for characterization of regional surficial and bedrock geologic units. Access to penetrative data may be accomplished by filing a Freedom of Information request with the New York State Department of Environmental Conservation (NYSDEC).
Landfill siting and operation are governed by 6 NYCRR Part 360 regulations. This regulatory document contains a de facto table of contents for a comprehensive hydrogeologic investigation of landfill sites. Furthermore, the regulations require a literature search and analysis of broader, regional data in order to provide a context for definition of site-specific, hydrostratigraphic units. When properly completed, resultant hydrogeologic reports contain a plethora of penetrative and water quality data, as well as hydrogeologic interpretations, that academic researchers would find difficult to fund through grant-lending agencies. Consequently, in the course of local geologic or water resource investigations, hydrogeologic reports for landfill sites should not be ignored. When reconciled with data published by the U.S.G.S., U.S.D.A. Soil Conservation Service, NY State Geological Survey, and the academic community (e.g. in NYSGA guidebooks!), these hydrogeologic reports add considerable volumes of quantitative information to any geologic research database.
The purpose of this field trip is to provide an overview of the hydrogeologic aspects of the Part 360 regulations and to illustrate the diversity of hydrogeologic data collected for landfill sites. Furthermore, this article is intended to demonstrate how Part 360 data may be synthesized for characterization of geologic units in western New York. The field trip will also provide an opportunity for landfill operators to demonstrate how modern, secure facilities are planned, designed, operated and closed to minimize negative environmental impacts.
PART 360 LANDFILL SITING PROCESS
Landfill siting is a controversial and expensive proposition in New York State. The process had been particularly controversial for the private sector under previous versions of Part 360. One particular problem would commonly arise when a potential landfill site was selected, based upon economic and/or geographic characteristics, before performance of a formal Part 360 site selection study. Site selection studies, both under previous and current versions of Part 360, involve comparison of potential sites on the basis of hydrogeologic, engineering and socioeconomic properties. Ideally, the site selection process provides a means to determine the "best" site out of many potential landfill locations. Prior to the October 9, 1993 revision to the Part 360 regulations, when a preferred site would be chosen before other candidate sites were identified, expensive siting studies would subsequently have to be "retrofitted" to produce the desired conclusion that the preferred site is the most appropriate location among other "straw-man" candidate sites for the facility.
The New York State Department of Environmental Conservation apparently recognized the quandary in which project sponsors found themselves when the preferred, suitable site was identified prior to completion of the formal site selection study. Furthermore, the NYSDEC also apparently recognized that, because siting studies require analysis of non-hydrogeologic variables (e.g. transportation, population, utilities, etc.), less hydrogeologically suitable sites could potentially be promoted over sites with more desirable subsurface characteristics for reasons other than susceptibility to groundwater and surface water contamination. Apparently for these reasons, the NYSDEC recently revised the Part 360 siting process for project sponsors who identify sites that exceed minimum hydrogeologic and engineering criteria for landfill construction. Under certain specifically stated hydrogeologic conditions, an expensive site selection study may not be required to defend the obvious merits of a highly suitable site. The revised regulations ease the financial burden and the logistical difficulty in objective compliance with landfill siting requirements when specified hydrogeological conditions are met. By establishing standards which must be met in order to waive the requirement for a site selection study, the NYSDEC can still guarantee that landfills can be constructed and operated in a manner which minimizes the potential for negative impacts to humans, wildlife or the environment.

A1:THE HYDROGEOLOGY OF LANDFILL SITES IN WESTERN NEW YORK

STOP 1. BRIGHTON TOWN LANDFILL Facility: Brighton Solid Waste Management Facility
Location: Town of Brighton, Monroe County (Rochester East 7.5" Quadrangle)
Hydrogeologic Setting: Glaciolacustrine deposits and glacial till over bedded sedimentary rock.
Site Description: The site is located on the northeast-facing side of the Irondequoit Creek valley. The site includes 75 acres; only 24 acres are considered suitable for waste disposal purposes. Topographic relief across the active portion of the site is approximately 150 feet; the average topographic slope is approximately 5 percent. The site is bounded on the west by Thomas Creek, a small tributary of Irondequoit Creek, and on the north and east by Irondequoit Creek. Irondequoit Creek drains into a major bay (Irondequoit Bay) of Lake Ontario.
The following items, listed in the Part 360 Permit Application for this facility, reflect current site conditions:
• There is no evidence of leachate derived from this facility.
• Natural vegetation is present on previous disposal areas.
• Vegetation is established on all slopes of disposal areas.
• There is no evidence of significant erosion occurring on site.
• The disposal area is adequately covered and graded to maintain safe and efficient storm water runoff.
Surficial Geology: Overburden consists of probable lodgement till overlain by interbedded flow tills and stratified silt-to sand-rich glaciolacustrine facies. The overburden ranges in thickness from 22 to approximately 100 feet. The overburden is thinnest at the topographically highest (southwestern) portion of the site and thickens towards Irondequoit Creek, to the northeast. The strike of the surficial deposits generally follows the topographic contours of the valley.
The interbedded, stratified glaciolacustrine facies and water-lain till deposits include evenly laminated silt (offshore lacustrine deposits), evenly-and cross-laminated coarse silt and very fine sand (nearshore lacustrine deposits), and gravelly, clay-rich silts (tills). Based on detailed boring logs, split-spoon samples (Huntingdon-Empire Soils Investigations, Inc., 1994), and outcrop sections, the glacial and proglacial strata include, in descending order:
Unit 1: | Evenly laminated silt (10 to 25 feet thick)
Unit 2: | Very fine, silty sand (5 to 15 feet thick)
Unit 3: | Gravelly, clay-rich silt (5 feet thick)
Unit 4: | Evenly laminated silt (> 5 feet)
Unit 5: | Undifferentiated deposits (No boreholes with detailed logs or available split spoon samples penetrated Unit #4. However, tills are present over bedrock throughout the lower Irondequoit Creek valley.)
This succession mostly records accumulation in a proglacial lake basin. The glaciolacustrine succession disconformably overlies lodgement till that accumulated during the earlier glacial advance. A minor glacial advance is recorded by Unit 3, a waterlain diamicton or subaqueous flow till. The stratigraphic record of this advance is asymmetrical: offshore silts are overlain by flow till, and the flow till, in turn, is overlain by nearshore sands. Unit 3 may correlate with the Somerset Till described by Calkin and Muller (1992) 'from sections along the Lake Ontario shoreline. In general, lacustrine silts and sands are extremely well sorted with D10 values on the order of 0.05 mm or less for the very fine sands. N-values for these deposits generally range from 15 to refusal, with the lower N values correlating to shallowest subsurface sandy deposits.
Bedrock-Geology: Based on reported depth to bedrock, strata assigned to the Lower Silurian Medina and Clinton groups probably subcrop beneath glacial sediments. These strata consist of sandstone, shale, and limestone. In ascending order, the following formations are likely subcrop beneath the site: Grimsby Sandstone, Cambria Shale, Kodak Sandstone, Maplewood Shale, Reynales Limestone, and Sodus Shale.
Groundwater Flow: Groundwater flow is topographically controlled. Groundwater equipotentials are generally parallel to topographic contours; groundwater flows to the northeast.
1994 A1 W.M.Goodman, R.B.Cole, D.F.Lehmann #msn_Aqua -77.53418955435217,43.16206173306232,0 STOP 2. HIGH ACRES LANDFILL Site Location: Town of Perinton, Monroe County, New York Fairport and Macedon 7.5 Minute Quadrangles
Site Description: The east side of the site contains a north-south trending drumlin. The existing operational facility is constructed on the drumlin. The west side of the site is relatively flat-lying, interdrumlin terrain. The western area is presently under construction as a lateral expansion area to the landfill.
Surficial Geology: The drumlin on the west side consists of two separate till horizons: a lower, gray, bouldery lodgment till and an upper, brown weathering "altered till". The upper till contains fewer cobble and boulder size clasts than the basal, unaltered till (Dan Coon, personal communication). Given the difference in grain-size composition and density, the upper till may actually represent a separate genetic unit. One hypothesis is that the basal till correlates with the Furnaceville Till, whereas the upper till is correlative to the Somerset Till.
In the interdrumlin areas of the west side of the site, the surficial stratigraphy is more variable. The basal till that directly overlies bedrock is also divisible into a lower, unaltered zone and an upper weathered zone. The presence of this horizon may suggest a period of subaerial exposure prior to deposition of the overlying recessional sequence. Such an interpretation, however, is difficult to reconcile with the regional glacial history. An alternative hypothesis is that the "weathered till" may represent the diamictic facies of the younger Somerset Till equivalent and that the mixed water-lain and till deposits ("glacial till/outwash" deposits of Eckenfelder, 1992) may correspond to the upper water-lain till facies of the Somerset Till as defined by Calkin and Muller (1992).
Bedrock Stratigraphy: The bedrock strata that subcrop beneath glacial tills on the site are assigned to the upper part of the Silurian Vernon Shale. Eckenfelder (1992) reports that the drill core sections consist primarily of red and green shale with varying amounts of gypsum. Gamma ray logs were used to correlate borehole sections. Through correlation of gamma ray logs, Eckenfelder (1992) was able to document the regional southward dip of bedrock strata.
Groundwater Flow Conditions: Shallow groundwater flow tills and glacial outwash is topographically controlled. On the east side of the site, groundwater in the brown till horizon flows radially off the drumlin. In flat-lying areas, groundwater flow generally proceeds to the south. The low permeability of the glacial tills results in vertically oriented groundwater flow vectors. Flow lines are deflected to a more horizontal orientation in lenses of glacial outwash.
The bedrock fracture zone provides a preferred groundwater flow path. Upward gradients are common between the fractured bedrock zone and the underlying competent bedrock zone.

STOP 2. HIGH ACRES LANDFILL
Site Location: Town of Perinton, Monroe County, New York Fairport and Macedon 7.5 Minute Quadrangles
Site Description: The east side of the site contains a north-south trending drumlin. The existing operational facility is constructed on the drumlin. The west side of the site is relatively flat-lying, interdrumlin terrain. The western area is presently under construction as a lateral expansion area to the landfill.
Surficial Geology: The drumlin on the west side consists of two separate till horizons: a lower, gray, bouldery lodgment till and an upper, brown weathering "altered till". The upper till contains fewer cobble and boulder size clasts than the basal, unaltered till (Dan Coon, personal communication). Given the difference in grain-size composition and density, the upper till may actually represent a separate genetic unit. One hypothesis is that the basal till correlates with the Furnaceville Till, whereas the upper till is correlative to the Somerset Till.
In the interdrumlin areas of the west side of the site, the surficial stratigraphy is more variable. The basal till that directly overlies bedrock is also divisible into a lower, unaltered zone and an upper weathered zone. The presence of this horizon may suggest a period of subaerial exposure prior to deposition of the overlying recessional sequence. Such an interpretation, however, is difficult to reconcile with the regional glacial history. An alternative hypothesis is that the "weathered till" may represent the diamictic facies of the younger Somerset Till equivalent and that the mixed water-lain and till deposits ("glacial till/outwash" deposits of Eckenfelder, 1992) may correspond to the upper water-lain till facies of the Somerset Till as defined by Calkin and Muller (1992).
Bedrock Stratigraphy: The bedrock strata that subcrop beneath glacial tills on the site are assigned to the upper part of the Silurian Vernon Shale. Eckenfelder (1992) reports that the drill core sections consist primarily of red and green shale with varying amounts of gypsum. Gamma ray logs were used to correlate borehole sections. Through correlation of gamma ray logs, Eckenfelder (1992) was able to document the regional southward dip of bedrock strata.
Groundwater Flow Conditions: Shallow groundwater flow tills and glacial outwash is topographically controlled. On the east side of the site, groundwater in the brown till horizon flows radially off the drumlin. In flat-lying areas, groundwater flow generally proceeds to the south. The low permeability of the glacial tills results in vertically oriented groundwater flow vectors. Flow lines are deflected to a more horizontal orientation in lenses of glacial outwash.
The bedrock fracture zone provides a preferred groundwater flow path. Upward gradients are common between the fractured bedrock zone and the underlying competent bedrock zone.

STOP 3. PROPOSED HYLANDS ASH MONOFILL
Facility: Hylands Ash Monofill
Location: Town of Angelica, Allegany County (Angelica 7.5" Quadrangle)
Hydrogeologic Setting: Glacial Till Over Bedded Sedimentary Rock.
Site Description: The site contains a broad, south facing, hanging valley that forms a natural amphitheater. A small intermittent stream is supplied by a bedrock spring along the east side of the site and by overland flow toward the valley center in the southern portion of the hanging valley. Surface water drainage flows into Angelica Creek which, in turn, discharges to the Genesee River.
Surficial Geology: Glacial overburden consists of lodgement till overlain by ablation till. The overburden ranges in thickness between approximately 5 and 11 5 feet. The till is thinnest on hill crests and thickens rapidly toward the center of the hanging valley. An oxidation front marked by the vertical change from gray, unaltered till to brown, weathered deposits cross-cuts and partially obscures the lodgement till/ablation till contact. The lodgement till is over consolidated; assuming no net erosional lost of glacial sediments near the valley floor, the brown, oxidized lodgement till is estimated to have been compacted beneath a minimum of 500 ft. of ice and probably considerably more (Michael Mann, personal communication). The ablation till is generally less dense than the lodgement till and contains thin, discontinuous, water-sorted lenses.
High subglacial pore pressures are suggested by the fracturing of bedrock and injection of till seams to depths approaching 200 ft. below ground surface. The upper 20-30 ft. of rock is typically so intensely fractured that the contact between glacial till and bedrock may be completely gradational. In ascending order, the gradational interval consists of 1) in-situ rock mass with till seams; 2) approximately even proportions of in-situ rock mass and till with gravel-sized angular rock fragments; 3) boulder-size, rotated or detached blocks of bedrock in a gravelly clay till matrix (deformation till); and 4) channery lodgement till.
Bedrock Geology: Strata are assigned to the Upper Devonian (Fammenian) Canadaway and Conneault Groups and consist of a series of interbedded, fossiliferous sandstones, siltstones and clay shales (see Fig. 6A). In ascending order the following formations subcrop on site: Machias Shale, Cuba Sandstone and Wellsville Shale. The site is situated on the northwest limb of a northeast trending anticline. Strata dip to northwest at approximately 1 degree.
Groundwater Flow: A perched water table exists in the ablation till profile in the valley center. The perched groundwater table is recharged by interflow and overland flow directed toward the valley center from the east, west and north. Along the axis of the valley, groundwater flows southward toward the intermittent stream.
Groundwater flow in bedrock is divided into two flow systems. A high elevation flow system contains a recharge area in open pastures upgradient (east) of the site. The discharge zone occurs at the spring line that marks the base of the Cuba Sandstone subcrop belt along the east side of the site. A second, deeper bedrock flow system occurs in the Machias Shale beneath the landfill footprint. Strong downward gradients are characteristic of the upper portion deeper bedrock system. The horizontal flow vector is directed primarily to the west/southwest. Westward flow on the east side of the till-filled valley is impeded by the gray till aquiclude. Consequently, artesian pressure builds in the deeper bedrock system in the southeast corner of the site. Hydraulic gradients in bedrock beneath the west side of the site are steeply downward. Flow diverges on either side of the topographic divide in the shallow rock profile beneath the western site boundary. Deeper flow in rock trends toward the west/southwest.

A2: SUBSURFACE GEOLOGY OF THE LOWER GENESEE RIVER VALLEY REGION: A PROGRESS REPORT ON THE EVIDENCE FOR MIDDLE
WISCONSIN SEDIMENTS AND IMPLICATIONS FOR ICE SHEET EROSION MODELS
RICHARD A. YOUNG
SUNY College at Geneseo
Geneseo, NY 14454
LES SIRKIN
Garden City, NY 11530
Deep bore holes and gravel pit exposures in the Genesee Valley region north of Avon (Figure 1 ,9) have provided a number of organic-rich sedimentary horizons that have been dated at the University of Arizona AMS facility in the range between 26,000 and >48,800 years BP. A majority of the finite age determinations lie within the interval from 30,000± to 43,700± years BP, implying a Middle Wisconsin age for the deposits sampled. Most of the materials dated were collected from buried glacial outwash, lacustrine sequences, or overridden peat incorporated in younger till. The stratigraphic relationships suggest that the dated materials are most likely correlative with the Plum Point and/or Port Talbot Interstadials best known from localities in Ontario, Canada.
The most likely timing of the main ice advance into the Genesee Valley, based on the average of the best constrained ages, is circa 35,000± years BP. This coincides with the recent revision of the H-4 Heinrich event (iceberg discharges) in the north Atlantic and the Dansgaard-Oeschger cycles seen in the Greenland ice· cores (Bond and others, 1992, 1993; Taylor and others, 1993).
Whether or not Middle Wisconsin ice crossed the south shore of Lake Ontario and advanced very far into western and central New York has been a controversial subject (Berger and Eyles, 1994; Dreimanis, 1992; Hicock and Dreimanis, 1992). The implied extension of the southern margin of Middle Wisconsin ice sheets into the Genesee Valley and the northern Finger Lakes region has obvious implications for global climatic reconstructions and for additional fine tuning of eustatic sea level curves for the interval represented.
The most diverse and best sampled sections are located in two adjacent sand, gravel, and clay pits in northern Livingston County on the west side of the Genesee River where Middle Wisconsin strata are covered.by only 20 to 40ft (6 - 12 m) of Late Wisconsin glacial drift. Preservation of these Middle Wisconsin sections in an area of low relief within the broad Genesee Valley raises theoretical questions concerning how the older unconsolidated sediments survived being overridden by the younger, Late Wisconsin ice advance, which extended about 125 km (76 mi) further south into Pennsylvania. The near surface outcrop location also raises the question of under what circumstances ice sheets scour deep, well-defined bedrock troughs as opposed to advancing across unconsolidated sediments with little apparent erosive impact.
The existence of such a complex Wisconsin section also raises the issue of what similar stratigraphic sequences may be present throughout upstate New York that might not have been recognized due to an absence of preserved or obvious organic horizons. The Middle Wisconsin sediments in the sections studied in the Genesee Valley are very similar in appearance to overlying drift units, and except for the fortuitously preserved organic horizons, the stratigraphy and field relations do not appear very dissimilar from numerous other glacial drift exposures across the region. It is possible that the glacial drift stratigraphy of the region preserves a more complex record of Middle (or older) Wisconsin events than has been assumed, especially within bedrock troughs such as the Genesee Valley and adjacent Finger Lakes.

A2: ROAD LOG FOR LOWER GENESEE RIVER VALLEY MIDDLE WISCONSIN SITES AND GLACIAL GEOMORPHOLOGY IRONDEQUOIT BAY OUTLET TO CANASERAGA VALLEY
Objective: The purposes of this trip are: 1) to visit the two sites in the Genesee Valley that have recently produced the evidence for a Middle Wisconsin glacial advance (-35,000 BP) to near the latitude of Avon, N.Y., and 2) to provide an overview of the glacial geomorphology created by Late Wisconsin ice withdrawal from the lower basin. The events that shaped the surficial geomorphology of the modern valley are clearly related to the major preglacial lake stages, lake outlets, and prominent moraines found from the Valley Heads Moraine near Dansville to the Pinnacle Hills Moraine in Rochester. The geologic setting of the valley can best be appreciated by referring to the review articles by Muller and Calkin (1993), and Muller and others (1988). The existence of shallow, Middle Wisconsin tills, outwash gravels, and lacustrine sequences close to the elevation of the modern flood plain within the broad, open valley pose obvious questions about mechanisms of Late Wisconsin ice erosion and the possibility that similar sections might be preserved elsewhere in central New York.

STOP 1. SITE OF BAYMOUTH SAND BAR BUILT DURING RISE FROM EARLY LAKE ONTARIO
This location provides one of the few good overviews of the relief and topography of Irondequoit Bay, the baymouth bar, and their relationships to Lake Ontario. An orientation stop will be made here to view cross sections and large out-of-print and unpublished maps of geology and engineering projects used to interpret sections cored through the sand bar to depths of 380ft (116m). The geologic relations in the accompanying text Figures (2-8) will serve to focus the discussion. The Rt. 104 bridge can be seen spanning the bay 1.5 miles to the south. Eighteen deep exploration boring logs provide a detailed cross section view at the bridge (Kappel and Young, 1989) to compare with the subsurface stratigraphy cored by water test wells and bridge foundation borings at the sand bar.
The long bluffs to the southeast (nearly parallel to the bar), which dominate the anomalous northeast trend of the adjacent Bay shore appear to represent the north edge of an unnamed moraine potentially correlative with the Carleton Moraine to the west. An ice-contact feature in this position would reasonably account for the unusual and abrupt change in the shoreline trend near the mouth of the Bay. Gravel pits formerly present on the south edge of this northeast-trending ridge exposed coarse gravel and sand sequences with a southerly dip (now under Stony Pt. development), presumably the outer margin of a kame moraine complex. Older topographic maps (1935) show the top of the bluffs to have been a low ridge bordered by a large irregular depression at its western limit.
A moraine of this age would have been closely associated with the withdrawal of ice near the time of Lake Iroquois, whose shoreline (elev. 435± ft) lies about a mile south of the moraine at the location of Ridge Road (Rt. 104).

STOP 2. KAME MORAINE FAN AND LACUSTRINE SEQUENCE ON SOUTH EDGE OF BURIED PINNACLE HILLS MORAINE
Walk down slope to Irondequoit Creek, proceed upstream to Bridge and cross to exposure of Kame moraine fan with lacustrine sequence at top.
The Pinnacle Hills Moraine (most prominent pre-Lake-Iroquois moraine) extends from the University of Rochester to near this location where it is largely buried within the older Irondogenesee Valley, covered by lacustrine sediments from contemporaneous and younger glacial Lakes Dana(?), Dawson, and Iroquois (Fairchild, 1928; Muller and others, 1988). The till portion of the moraine seems to divide the groundwater regimes of the upper and lower Irondequoit Basin. The subsurface extent of the moraine was studied in a series of borings in an attempt to define its effect as a groundwater barrier and is described in Kappel and Young (1989). Groundwater upstream of the moraine appears to be locally more saline (trapped road salt) than groundwater north of Browncroft Blvd. This stop will utilize the cross section Plates from Kappel and Young (1989) and Figures from Young (1988) to examine what is currently known of the moraine and the size of the buried valley.

Pinnacle Hills moraine can be seen clearly on right 2 miles to north (radio towers).

STOP 3. VIEW AREA OF MIDDLE WISCONSIN SECTION SHOWN IN FIGURES 9, 10,11 OF ACCOMPANYING ARTICLE.
The geology of this stop is the focus of the second half of the accompanying article. It is the only complex Middle Wisconsin exposure in New York with the range of different depositional units, organic horizons, and multiple ice advances recorded both in this pit and the DeWitt gravel pit immediately to the south. The site has changed markedly over the past 4 years due to rapid extraction since the peat horizon in the lower till was discovered by R.A. Young in November 1990. The major units and dated horizons have largely been removed, but most of the section from the "bone horizon" (Figure 10) upward is still visible (June 1994) and the only good wood specimen found to date was collected from the lower till during a summer 1994 visit (submitted to Arizona AMS Lab). The local deposits have been used to supply "clay" to the new Monroe County (Rochester) Mill Seat Landfill in Riga, thus accounting for the rapid excavation of the lower rhythmite section, largely below the present pit water table. The success of this visit will depend entirely on how much excavation or construction occurs during the 1994 summer season and how much remains of the section shown in Figure 10 between this writing (June 1994) and October of 1994.
The DeWitt pit immediately adjoining this site on the south will be included in the stop, either by hiking across both pits (water conditions permitting) or rejoining the bus for a short ride. Participants are cautioned to stay clear of all vertical bluffs where very large (and dangerous) segments of the clay and gravel units slump unexpectedly.
If conditions are favorable time spent at this stop may be extended and the remainder of the trip shortened to allow interested participants to adequately explore this important, but rapidly disappearing site.

Cross Conesus Lake outlet.

Fowlerville Rd. Delta on right built into glacial Lake Scottsville.

Moraine (hill) on left is site of mastodon find in 1989-90.

STOP 4. INFORMAL STOP ALONG ROUTE 39 OVERLOOKING VALLEY
A broad moraine complex arcs westward into valley (road follows crest for ~3 miles) marking late Wisconsin ice readvance. The moraine is undated but is thought to be approximately correlative with Alden, Buffalo, and Niagara Falls moraines (Muller and others, 1988). The moraine is difficult to see from any given point but fills the Genesee Valley between Geneseo and Avon (1:24 000 topo.), eliminating the broad flood plain characteristic of the Genesee Valley to the north and south of this reach.

Roots Tavern Rd. on right marks end of obvious moraine ridges on topographic map.

STOP 5. VIEW OF ALDEN MORAINE NEAR ICE POSITION THAT CREATED LAKE HALL (-1000 ft elev.)
Genesee Valley south of this latitude was filled by Lake Hall as the ice retreated from the Alden moraine. The drainage outlet was to the west through the prominent Pearl Creek outlet where a large delta was built into the Wyoming Valley. The next leg of the trip will descend into the Pearl Creek outlet channel and climb out to the south, descending to the shoreline of glacial Lake Warren near elevation 845 ft.

STOP 6. STOP AT LAKE WARREN BEACH WITH VIEW EAST INTO GENESEE VALLEY
Glacial Lake Warren was the last large glacial lake embayment extending southward into the Genesee Valley from an ice front position near the NY State Thruway between 13,000 to 12,600 BP (Muller and Calkin, 1993). The shoreline presently indicates a relative postglacial uplift to the north of approximately two feet per mile between Geneseo and Victor, New York. Lake Warren shoreline features can clearly be seen along both sides of the Genesee Valley on aerial photographs southward to the latitude of Letchworth Park, whereas no other glacial Lake shorelines are still as obvious or continuous.

A3: GEOLOGY OF THE ERIE CANAL, ROCHESTER GORGE, AND EASTERN MONROE COUNTY, NEW YORK STATE: IN THE FOOTSTEPS OF AMOS EATON AND JAMES HALL
THOMAS X. GRASSO
Geosciences Department
RICHARD M. LIEBE
SUNY Brockport
Brockport, New York 14420
The Phelps and Gorham Purchase, from the Seneca Nation in 1788, opened the lands west of Seneca Lake for settlement. Westward migration began as a trickle, but with the coming of the Erie Canal to the Genesee Country in 1822-23, a flood of immigration occurred that transformed western New York from dense forest to farmland, villages, and cities. For example, Rochester's first permanent settler did not arrive until 1812 while real growth blossomed in the 1820's. From the colonial period to the opening of the canal the west began at Schenectady.
The growth of geologic thought followed a similar pattern. A few random notices and sketches were made early on, primarily by army officers serving during the colonial wars and the Revolution. The Erie Canal changed all that. The surveys for the proposed project required organized, detailed, observations of the terrain and its underlying geology. Enter now DeWitt Clinton whose 1810 chronicle of a journey across the state, along with other writings, records numerous observations and interpretations of the geology from Albany to Buffalo. However, it wasn't until the seminal work of Amos Eaton (Father ofNew York Geology) in 1824 (A Geological and Agricultural Survey of the District Adjoining the Erie Canal in the State of New York) that a comprehensive and amplified attempt was made to unravel the superposition of western New York's strata. The foundation he laid ultimately led to the founding of the State Geological Survey in 1836. The following year James Hall came to the Genesee Country and examined its fossiliferous strata. Hall's work from 1837 to 1843 finally unraveled the stratigraphic column of western New York as we know it today, save for some modern refinements. This paper attempts to show the evolution of geological investigations in Eastern Monroe County and Rochester as revealed in the writings and quotations of Amos Eaton and James Hall. The Erie Canal, its history and geology, and the geology of the Rochester Gorge are equally main themes as they provided the framework for the development of geologic thought.
In 1826 Amos Eaton led an expedition by canal boat across New York State. The surviving journals of two of the participants, George W. Clinton and Asa Fitch, provide unique insights into the state of geological knowledge, the nature of the landscape, and human development in the region at that time. These are quoted throughout the text but more liberally so in the roadlog. The writings of James Hall and to a lesser extent Sir Charles Lyell, are included to illustrate the degree of scientific advancement in the score or so years following Eaton's labors.
The paper is divided into five major subdivisions including the roadlog. The life, geological thoughts, and contributions of Amos Eaton is followed by a section on James Hall which contains a brief description of the rise of the New York State Geological Survey. The middle portion is devoted to the history and geology of the Erie Canal and its impact on New York State. With all of the historical perspectives in place the paper proceeds to the site specific, fourth, section-a discussion of Rochester and the Rochester Gorge. Finally the roadlog and boat trip is devoted principally to retracing the route of Amos Eaton's 1826 tour to the Rochester Gorge. The journal entries of the participants illuminate what travel was like at that time as well as highlighting Eaton's personality and ideas. Here Eaton's geology is contrasted with that of James Hall along with today's interpretation of the stratigraphic sequence and glacial topography. Hall's ideas are revealed in his 1837 field notebooks housed in the New York State Library in Albany and of course his monumental 1843 Survey of the Fourth Geological District.

A3: GEOLOGY OF THE ERIE CANAL, ROCHESTER GORGE, AND EASTERN MONROE COUNTY, NEW YORK STATE: IN THE FOOTSTEPS OF AMOS EATON AND JAMES HALL

Pinnacle Hill with TV transmitters on top on left at intersection of Clinton Ave.

I-590 is on alignment of Old Erie Canal.

Cross Erie Canal

Route East to Macedon offers many fine vistas of drumlins and other glacial features.

Cross alignment of Old Erie Canal. Old Lock 61.

Lock 30 (Macedon Lock) on the Barge Canal.
Lock 30 has a lift of 17 ft. (5 m) West and was completed in 1916.
Board canal boat SAM PATCH for Lock 32 (Pittsford Lock) west of Pittsford. (There is no Lock 31 ).

Head ofLock 30.
The Erie Canal here partly restored the flow of the ancient Great Lakes (and pro glacial) waters through the Fairport meltwater channels. From here to Fairport the canal route follows the main meltwater channel.

Old Erie Canal channel veers left (S)
Old Erie Canal channel veers left (S) of the present canal through the hamlet of Wayneport. Start of widewaters created by Barge Canal construction which allowed water of present canal to back up against old canal bed.

Old canal loop enters present alignment - west end of widewaters.

Lynden Road Bridge
This site was known as Knappville -a sleepy community in old canal days.

Fairport (Main Street) lift bridge (1914-1915)
One of sixteen between here and Lockport and the first one west of the Hudson River on the Erie Canal. Daniel and Hemy Deland established the Deland soda and saleratus (baking soda) chemical works on north bank of the canal just east of this bridge in 1852. It burned in 1893. The Box Factory and Village Cafe occupy the site.

NY31 bridge over canal.
This site was known as Fullamtown in Amos Eaton's time as Elisha Fullam, in 1822, built a tavern and warehouse here along with other buildings. Travelers proceeding west to Rochester often transferred to stagecoach at Fullamtown as the overland route was 8.5 miles (13.7 km) shorter.

Start of the Oxbow on left (E)
A large loop ofClinton's Ditch that was cutoff when the enlarged Erie was constructed through here circa 1855.

Site of Bushnell's Basin canal break in November 1974.
Canal washed out due to collapse of a sewer tunnel being bored beneath the canal. Navigation was not restored until late 1975 ... nearly a year later.

East (SE) end of the Great Embankment.
The Erie Canal vaults Irondequoit Valley nearly 60 feet (18 m) above the valley's floor. A culvert nearly 500 feet (152 m) long conveys Irondequoit Creek beneath the embankment. The passage high above the surrounding terrain was sharply curved at its western end (NW) as it followed the serpentine crest of the Cartersville Esker. Dryer (1890, p. 203) described it as a "kame which extends from Cartersville on the west to and beyond Bushnell's Basin on the east. The north end is a sharp ridge of very coarse gravel, fifty feet in hight [sic], one mile long and in shape like a rude fish-hook ..... Irondequoit river ..... has cut the kame completely in two. In the southern portion the gravel is overlain by fifty feet of fine sand which spreads out toward the southeast ..... The Erie Canal avails itself of this kame to cross the valley and by a fifty foot embankment restores what probably once existed as a natural feature." Upham (1893, p. 190-191) described the feature as part of an esker and kame belt " .... from a point about a mile east-southeast of Pittsford village to its termination about a mile southeast and south of the village of Bushnell's Basin ..... " Fairchild (1896, p. 135-136) described it fully beginning with ......"nearly opposite Cartersville and north of Bushnell's Basin is a conspicuous esker ..... " Giles (1918, p. 208-211) named the Cartersville Esker and included a contour map of its northwest portion near Pittsford.
The "rude fish-hook" part of the embankment was deemed too sharp for tugs and barges during Barge construction. Therefore, a new great embankment was built cutting off the esker loop and straightening the canal's alignment. The old loop is still marked by a line of trees north of the present canal.
The new embankment was begun in 1908 and completed in the spring of 1912. The original part of the older embankment over Irondequoit Creek was also modified at this time. In October, 1912, the Great Embankment over Irondequoit Creek collapsed down to the level of the creek in the worst canal breach of its history in this district. Water leaking through the new concrete floor eventually weakened the Irondequoit Creek culvert until it collapsed. Within a few weeks the breach was dammed at each end and a temporary wooden flume erected on piles 60 feet (18 m) high to convey canal boats across the break until the embankment and culvert could be rebuilt. This was accomplished in 1918. The south (SW) wall of the current trough bows outward where the flume used to be as the engineers poured the new wall around the flume. They removed it in the winter of 1917-1918 to pour the new concrete floor. Small tunnels (galleries) were built into the new structure to channel off any leaks and to permit visual inspection. This part of the embankments has held ever since.

West (NW) end of Great Embankment.
When Eaton's party crossed the embankment in 1826 blowing sand prevented them from having a good view of the Great Embankment

Mitchell Road bridge.
The Clinton's Ditch Pittsford Lock (Lock 73) was located just southeast of this bridge. The LAFAYETTE locked up through here on Saturday May 13, 1826.

NY31 bridge -Enter Pittsford
Between this bridge and the Main Street bridge is the Schoen Place district. In the later part of the 19th century and into the 20th century lumber yards, a malt house, and warehouses lined the south side of the canal while coal sheds, a flour mill, and fruit evaporators were located on the north side. A grain and bean processing mill and Pittsford Lumber Company still survive on the north side amid the rows of boutiques, shops, and restaurants.

Conrail bridge.
The south abutment of the bridge rests on the Barge Canal Bed of the Vernon Formation of Ciurca (1990). It is the youngest of four eurypterid bearing horizons in the lower 100 feet (30 m) of the Vernon Formation. When the canal is drained in the winter the exposure reveals several feet of black shale grading upward into greenish shale. The fauna consists of Eurypterus pittsfordensis and rare Mixopterus remains.
The other horizons, in order of superposition are the Harris Hill Bed, Monroe Ave Bed and the Pittsford Bed. Ciurca equates the "Gananda Bed" of Hamell (1978) with the Barge Canal Bed although the two are 10 miles (16 km) apart.

NY31-Monroe Avenue bridge.
The state maintenance shops near the west end of the bridge were built around 1928. Clinton's Ditch ran on the south side of the canal from here to Lock 32.

The Old Erie Canal veers north
The Old Erie Canal veers north towards Monroe Avenue and downtown Rochester. The present channel from here to Greece was opened in 1918.

Cross alignment of Clinton's Ditch in its northward course to downtown Rochester.

Clover Street (NY65) bridge and Lock 32.
Lock 32 (1917) is the third Pittsford Lock. The first, Lock 73 (1822), was located near the Mitchell Road Bridge; the second, 0.9 mile (1.5 km) north of here is the Enlarged Erie Lock 62 (STOP 1). Lock 32 has a lift of 25 feet (7.5 m).

Cross alignment of Old Erie Canal.
In World War II landing craft were built on the south side of French Road in the old canal.

STOP 1. Enlarged Erie Pittsford Lock 62 and Pittsford Shale.
Lock 62 had a lift of 9.2 feet (2.8 m), going west, and was completed as a single chamber, enlarged lock (110 feet by 18 feet; 33.5 m by 5.5 m) by Jesse Petersen in 1855 for $26,260.77. It was doubled by James Wiltsey in 1873 for $34,269.19. At the upper end of this second chamber a drop gate was installed instead of the typical vertically hinged miter gates. This new type of lock gate was horizontally hinged and operated like a draw bridge so that when it was open it rested upstream on the floor of the canal. It was the invention of George Heath and was called Heath's Tumble Gate. They were installed on many Enlarged Erie Locks. The lock was lengthened in 1887-1888 to permit the passage of double headers (two boats lashed together) by B.T. Smith for $25,021.26. The final improvement came in 1890 when a water powered turbine, propelled by the overflow water, was installed at the base of the vertical shaft at the head of the lock. The turbine was in turn connected to geared shafts that operated rope cables wound around capstans and winches which then pulled boats in and out of the locks. These appliances were installed by Nicholas and William Wewple for $1,100. Lock 62 was abandoned at the end of the 1920 season.
Walk along the drive a few hundred feet north of Lock 62 at the base of the canal embankment behind Wegmans.
Pittsford Shale -Several feet of black shale and thin dolostones are exposed here. Ciurca (1990) has redefined the Pittsford Shale restricting it to only the eurypterid-bearing black shale and associated dolostones and renaming it the Pittsford Bed. The Pittsford Bed bears enormous numbers of the eurypterid Hughmilleria socialis along with Eurypterus pittsfordensis, Pterygotus monroensis, and several other non eurypterid species.

I-590 is built on the alignment of the Old Erie Canal.

Old Erie Canal Lock 65 (Reservoir Lock) on right.
It had a lift of 8.8 feet (2. 7 m) going west. This was one of the five locks (Locks 62 through 66) east of Rochester that locked westbound boats up to the aqueduct level. Lock 66 was just west of Monroe Ave. and was the last lock west toward Lockport. Locks 32 and 33 on the Barge Canal accomplish the same task today. Clinton's Ditch took a large loop to the south here hugging the base of Cobbs Hill. Enlarged Erie construction cut off the loop thereby creating large "widewaters" between the new towpath and old canal bed. Lock 65 was at the east end of this "reservoir". Lake Riley in Cobbs Hill Park is all that remains today.

STOP 2. Genesee River, Aqueduct, Court Street Dam.
Just downstream from the Court Street bridge was the head of the 14 foot (4.3 m) cascade that was the original Upper Falls of the Genesee River at Rochester. They were blasted to make way for the first Erie Canal Aqueduct.
Farther downstream is the Broad Street bridge resting on the Enlarged Erie Canal Aqueduct made of Onondaga Limestone and built from 1836 to 1842 by Josiah Bissell for $445,347. When it was completed it had an interior width of 43 feet (13 m), a length of 800 feet (244 m), and was the third longest of the 32 aqueducts on the entire line of the canal. This structure replaced the Clinton's Ditch aqueduct that was just to the north. The original aqueduct was completed in 1823, had an interior width of only 17 feet (5 m), and was constructed of Grimsby Sandstone. This is worth noting because all other Old Erie Canal aqueducts had wooden trunks supported by stone piers, with arches only on the towpath side for its support. The engineers opted for the stone design due to the severe floods on the Genesee River before the Mount Morris Dam was completed in 1953 (Figure 12). The deck that supports Broad St. was built in 1924 and rebuilt as it stands today in 1974.
Upstream from the Court Street bridge is the Court Street Dam, called a sector dam because each gate is a pie shaped section of a circle. Gates are hinged at the base of the downstream side of the structure and float in a chamber notched into the bed of the river. The level of the water in this submerged chamber can be raised or lowered thereby controlling the gates and the pool above. The dam was completed in 1917, as part of the Barge Canal construction for the canal's Genesee crossing south of here at Genesee Valley Park. RG&E generates hydroelectric power at the west end of these structures.

Cross Broad Street.
The 1826 travelers put in at Child's Basin, located where the bank is today at the northeast corner of Broad and Exchange Streets.
Eaton's party arrived at Rochester on Sunday, May 14th. George Clinton walked back on the canal about one mile to examine some "lime rock" [Lockport] along the banks, finding fluorspar in it. Clinton wrote:
"In the afternoon visited the falls and procured specimens of the saliferous rock [Queenston, Grimsby], grayband [Kodak], ferriferous slate, [Maplewood], iron rock [Seneca Park], ferriferous sandrock [Reynales] ... At this place . . . the geodiferous limerock [Lockport] and the calciferous slate [Rochester] meet, the latter becomes geodiferous."

STOP 3 Penfield Formation, Lockport Group in the Genesee River
Stop at drive leading down to the back of the Convention Center and RG&E Water Street Substation just north of Broad Street. Follow the path, through the gate between the aqueduct and the south end of the RG&E brick building.
At the river level several feet of crinoid rich, coarse grained, sandy dolostone of the Penfield Formation may be examined. Ripple marks on the tops of some beds. The Penfield grades into the crinoidal Gasport Limestone and Goat Island Dolostone of the Niagara Region. These ledges are all that remain of the original Upper Falls.
The RG&E building rests on the original 1827 foundation of Hervey Ely's flour mill. Across the river in the park was the original site of Indian Allen's 1789 mill. Upstream, through the arches of the aqueduct, the Court Street dam can be viewed.

STOP 4. Lower Falls
Eaton's entourage arrived at the west side of the Lower Falls on Monday May 15, 1826. Asa Fitch recorded that they stopped at the Upper Falls on route but could only see a small portion of them from the west side. Arriving at the Lower Falls at 10:00 AM they stayed until 2:00PM. On the west bank Amos Eaton, upon his arrival, gave a lecture on the strata " ..... could see the rocks clearly. They are 1st Saliferous rock [Queenston, Grimsby], 2nd Grayband [Kodak], 3rd Ferriferous slate [Maplewood], 4th Ferriferous Sandstone [Reynales]. .... " "Swam across Genesee River twice about 1/2 mile above falls 1.25 mile wide ..... " George Clinton noted (p. 289): "Is not Mr. Eaton's ferriferous sandstone rather poorly characterized. Some of the layers resembled shell limestone, contain petrifactions, and effervescing strongly with acids; others exactly resembled in external appearance the calciferous sandrock [Little Falls Dolostone, Tribes Hill Formation] obtained at Nose Hill [the Noses east of Canajoharie] and contained the same imbedded minerals, viz. homstone, chalcedony, semiopal and agate. Is he right in considering shell-limestone, vermicular limestone and gypsum as mere beds in calciferous slate?"
The Genesee River, diverted from its preglacial outlet through nearby Irondequoit Bay, has carved a post-glacial gorge approximately two hundred feet (62 m) deep during the past twelve thousand years. The strata revealed in the Rochester Gorge at this section are Upper Ordovician to Middle Silurian, overlain by Pleistocene till. James Hall, along with A.W. Grabau, named and described several of the formations in the gorge including the Rochester Shale, the first formally designated stratigraphic unit in North America (Brett, 1983).
The oldest unit in the gorge is the Upper Ordovician Queenston Formation, a series of brick-red, thin bedded shales and siltstones with several sandstone layers near the top (Figure 21). Although only the upper 50 to 60 feet (15-18 m) are exposed here, the Queenston Formation is more than 1,000 feet (300m) thick and underlies much of the Lake Ontario Basin. The Queenston Formation represents extensive nearshore deltaic deposits, which covered much of the northern portion of the Appalachian Basin during Upper Ordovician time. This paleoenvironmental determination is based on well preserved sedimentary features including cross-stratification, ripple marks of both current and oscillation types, desiccation features including mud cracks, mud-chip pebble conglomerates, and sole marks (Liebe and Grasso, 1988). Following deposition of the Queenston, an interval of emergence prevailed, and a major erosion surface called the Cherokee Unconformity (Figure 17), widely traceable in eastern North America, was formed.
The overlying Grimsby Formation (also known as the "Red Medina") is a series of red-green mottled sandstones and silty shales. In his 1837 field notebook Hall originally described this unit (and the Queenston) as "sandstone, variegated, red and green, with fucoids." The base of the formation is marked by a massive 10 foot (3m) coarse grained sandstone interpreted by Martini (1972) as a "low energy beach and/or bar(?)" deposit. This unit is overlain by a "Highly burrowed sequence of high tidal flat-flood plain or lagoonal environment which is cut through at times by shallow distributary channels and/or tidal channels" (Martini, 1972). Intraformational conglomerates and mud cracks are common. Fossils are rare in the formation, but specimens of the inarticulate brachiopod Lingula have been found elsewhere, and some of the massive sandstones near the middle of the unit contain excellent casts of the trace fossils Arthrophycus alleghaniensis and Daedalus archimedes (Hall's fucoids). The conspicuous bioturbated (burrowed) zone, 12 feet (4 m) below the Kodak Sandstone apparently correlates with the Thorold Sandstone of the Niagara Gorge (Brett et al., 1990). The origin of the prominent color mottling is not clearly understood; however, the green splotches are generally thought to represent the irregular alteration of ferric iron to the ferrous state by either downward percolating ground water or the presence of disseminated organic material (Liebe and Grasso, 1988).
The Grimsby Formation grades into the Kodak Sandstone, a 6 foot (2m) thick, massive, fine grained, bioturbated gray sandstone. Hall, in his initial work in the Rochester Gorge, followed Eaton and described this unit as the "grayband", a coarse, gray sandstone which was harder than the underlying sandstones and less destructible. At one time the Kodak Sandstone was thought to be correlative with the Thorold Sandstone in the Niagara Gorge. Work by Brett et al. (1990) recognized that these units are two distinct sandstones separated by 10 feet (2-3m) of red and green shale, informally known as the Cambria Member of the Grimsby Formation. This coincides with the work of Chadwick (1935) and Fisher (1966) who used the name Kodak for the prominent formation that forms the caprock of the Lower Falls.
The basal unit of Sequence II is the Maplewood Shale, a smooth, platy, in-part calcareous shale that unconformably overlies the Kodak Sandstone. This unit was described by Hall in his field book (1837) as a "ferriferous slate, soft and green, contains a few shells, and near its limit below, a very thin stratum, sometimes two, composed almost wholly of shells" In addition to these thin limestone layers, phosphatic pebbles are common, especially in the basal portion. The Maplewood is approximately 21 feet (7 m) thick here but becomes much thinner to the west where it is correlative with the Neagha Formation in the Niagara Gorge. Both formations are thought to represent either quiet, offshore marine or lagoonal deposits as part of the initial flooding of the transgressing Sequence II sea into the Rochester area.
The youngest unit exposed along the access road to the Power Station is the Reynales Formation, although Hall (1843) first designated this unit the "Pentamerus Limestone" for the numerous pentamerid brachiopods present. The Reynales Formation consists mainly of21 feet (7 m) of gray, crystalline limestone or dolomitic limestone with numerous shale partings and is divided into three members. The lower member, the Brewer Dock Limestone 3 feet (1 m), is separated from the upper Wallington Limestone Member by the well known Seneca Park Hematite (1 foot; 0.3 m). The Seneca Park was previously known as the Furnaceville, but recent mapping by Brett et al. ( 1990) revealed that the iron ore in the Genesee Gorge is actually at a higher stratigraphic horizon than the type Furnaceville in Wayne County and, therefore, cannot be the same unit. The Seneca Park Member was originally deposited as a fossiliferous limestone. The hematite has since replaced most of the calcium carbonate; however, samples will still effervesce when acid is applied, indicating much of the original carbonate material remains. The mechanism and time of replacement are much debated, but consensus seems to favor a penecontemporaneous alteration of the original fossiliferous limestone by iron-rich solutions from streams descending the iron-rich Taconic landmass located in eastern New York State at that time.
The Wallington Member (17 feet; 5 m) is a coarse grained, fossiliferous limestone, with beds of the smooth shelled brachiopod Pentamerus, as well as corals and bryozoans. The combination of dense strata packed with fossils and the replacement of some of the fossils and beds with chert make this unit particularly resistant, well suited to form the cap rock of the Middle Falls. The Reynales Formation then represents a shallow, clear water, offshore marine deposit of Sequence II.
Visible along the walls of the Rochester Gorge, but not easily accessible at this locality, is the upper member of Sequence II, the Sodus Shale, as well as the Williamson Shale and Irondequoit Fm. (Sequence VI) and the Rochester Shale (Sequence V). The latter unit, as well as the overlying Decew and Lockport Dolostone (Sequence VI) will be seen at STOP 5.

Lower and Middle Falls on left.

STOP 5. High Falls (Upper Falls), Browns Race
Although visually attractive to visitors, the High Falls could rarely be seen as industrial development along Matthew and Francis Brown's mill race blocked the view. It was sometimes said that Rochester had developed the river, for commercial purposes, to such a degree that the best view of the river and its falls could only be had from the back door of a factory or mill.
The upper part of the Lewiston Member is exposed in the lowest part of the gorge's east wall below the Upper Falls while the Burleigh Hill Member of the Rochester Shale forms the conspicuous bulge in the middle portion (Figure 24). The overlying 25 feet (8 m) of the Gates Member makes up the upper portion of the gorge walls downstream from the Upper Falls while its uppermost beds form the brink.
The Decew Formation is exposed upstream from the lip of the falls, in the uppermost 6 to 10 feet (2 to 3 m) of the east side of the gorge just downstream from the falls and on the west side at the base of the stone wall, where the enterolithic structure is clearly discernible, (north wall of the Kidd Iron Works) east of the water wheel. Another exposure is at the top of Falls Street just north of its intersection with Brown Street.
Walk along Brown's Race Street to view Brown's Race at Commercial Street. From here walk east on Commercial Street and opposite the High Falls Parking lot climb the embankment to the railroad. Walking east cross the river on the north side of the railroad bridge above the lip of the falls. Excellent vistas of the gorge and the historic district are obtained from this bridge. Continue walking east and then north along the railroad spur for Genesee Brewery to the Platt Street (Pont de Rennes) bridge (see Figure 32 for a 1910 view taken from this bridge) crossing back to the west side and returning to the starting point.

A4: STRATIGRAPHY AND FACIES RELATIONSHIPS OF THE EIFELIAN ONONDAGA LIMESTONE (MIDDLE DEVONIAN) IN WESTERN AND WEST CENTRAL NY
STRATIGRAPHY AND FACIES RELATIONSHIPS OF THE EIFELIAN ONONDAGA LIMESTONE (MIDDLE DEVONIAN) IN WESTERN AND WEST CENTRAL NY
CARLTON E. BRETT and CHARLES A. VER STRAETEN
Department of Earth and Environmental Sciences
The Middle Devonian Onondaga Formation of New York generally represents broad, carbonate platform facies that were deposited in the northern part of the Appalachian Basin during early to middle Eifelian time. Finer-grained, more basinal facies in central New York shallow laterally to the east and west into more biologically productive platform settings toward the Buffalo and Albany areas. Numerous biostromal to biohermal buildups, which include pinnacle reefs in the subsurface of southern New York, are rooted in the shallowest-water basal Onondaga facies.
Carbonates of the Onondaga Formation are characterized by calcarenitic to cherty to argillaceous limestones and minor shales deposited in a shallow epicontinental sea. The formation comprises a generally deepening-upwards succession, but apparently represents two major (third order) transgressive-regressive cycles. It is generally subdivided into four members across New York State (Edgecliff, Nedrow, Moorehouse, and Seneca, from the base upwards; Oliver, 1954; Rickard, 1975). A fifth member (Clarence) has been recognized only in western New York (Ozol, 1964; Oliver, 1966b); we herein designate the Clarence as a local facies of the Edgecliff Member.
The basal contact of the Onondaga Limestone is conformable in parts of eastern New York, but westward becomes unconformable and overlies increasingly older Devonian to Silurian strata. Throughout western and central New York State Eifelian-age strata are underlain by a major sub-Onondaga unconformity, commonly referred to as the Wallbridge Unconformity. The Wallbridge was recognized long ago by Sloss (1963), as one of the major sequence-bounding erosion surfaces in the Phanerozoic of North America. He used it to define the boundary between his Tippecanoe and Kaskaskia Megasequences. In actuality, the sub-Onondaga unconformity in Western New York State is a composite of two to three distinct erosion surfaces which are locally merged (Oliver, 1966c; see below). The nature of the upper contact has long been debated; it appears to represent a westward-younging, sediment-starved, submarine unconformity below overlying black shales at the base of the Middle Devonian Hamilton Group.
Underlying the Onondaga Formation in some parts of west-central to western New York are quartz arenites and minor carbonates of the upper Lower Devonian Tristates Group. These rocks, which include strata equivalent to the Oriskany Sandstone and/or the Carlisle Center and Schoharie Formations of eastern New York, occur sporadically across the region. In the Buffalo region a westwardly-thickening wedge of cherty limestone (Bois Blanc Formation) appears and thickens into southern Ontario.
Limestones of the Onondaga Formation (Figure 1) represent relatively tabular, clean, dominantly biogenically-derived sediments deposited in the northern part of the Appalachian Basin during a period of relative tectonic quiescence. Underlying and overlying clastics (Lower Devonian Tristates Group and Middle Devonian Hamilton Group, respectively) represent terrigenous sediments shed from a rising mountain belt in New England during two separate active "tectophases" of the Devonian Acadian Orogeny (Ettensohn, 1985). The concentration of altered volcanogenic strata (Tioga Bentonites/Ash Beds of Dennison and Textoris, 1970, 1978, 1987) in the upper part of the Onondaga Limestone heralds the progradation of clastic sediments into the Appalachian foreland basin.
Interestingly, the area of maximum erosion and, presumably greatest uplift, during pre-Onondaga Emsian time experienced an inversion of topography in the early Eifelian. The main basin axis during deposition of the Onondaga Formation was a northeast-southwest oriented trough of active subsidence that intersects the New York outcrop belt approximately at the location of the central Finger Lakes (e.g., Seneca Stone quarry between Seneca and Cayuga Lakes =Stop 6 of this trip), but which migrated eastward through the Eifelian.
In this paper we will examine the following: 1) a new detailed stratigraphy for the Middle Devonian Onondaga Formation and associated underlying strata in western to west-central New York; 2) the occurrence of the Tioga Bentonites cluster in the Onondaga Formation; 3) apparent lateral shifts in more basinal facies through Onondaga time; 4) a sequence stratigraphic interpretation of the Onondaga and underlying strata of the upper Lower Devonian Tristates Group; and 5) a new regional synthesis of the Onondaga Formation and equivalent strata in the northern and central parts of the Appalachian Basin (New York and Pennsylvania).
THE LOWER PART OF THE MIDDLE DEVONIAN MARCELLUS "SHALE," CENTRAL TO WESTERN NEW YORK STATE: STRATIGRAPHY AND DEPOSITIONAL HISTORY
CHARLES A. VER STRAETEN
DAVID H. GRIFFING
Binghamton, New York 13902
A major succession of Middle Devonian siliciclastic rocks (Hamilton Group), which ranges from 90 m to approximately 1,000 m in thickness, overlies carbonates of the Onondaga Limestone all across New York. The lowest part of these clastics is composed of black shale-dominated strata with minor limestones, and eastwardly coarsening, more sand-dominated, progradational strata, presently referred to as the Marcellus Formation. The Marcellus Formation is the lowest of four formations in the traditional subdivision of the Hamilton Group in New York State (Cooper, 1930, 1933, 1934).
Part of this fieldtrip will concentrate on lower Marcellus strata, which across New York consist of black shales, some thin limestones, and in eastern outcrops, calcareous shale to sandstone facies. These strata range in thickness from zero to less than one meter southwest of Rochester to over 180 m in southeastern New York near Kingston (Figure 1). Recent detailed work across the state indicates that the lower part of the Marcellus Formation comprises a fifth major cycle within the Hamilton Group, which is best developed in eastern New York (Brett and Baird, in press). In addition, the fauna of this interval is distinctly different from that of underlying and overlying rocks. With this in mind, we would like to present an informal preview of a new revision of the lowest part of the Hamilton Group that recognizes the significance of these strata. The revised stratigraphic nomenclature will be formally proposed elsewhere. In this revised scheme, the "Marcellus Formation" will be raised to subgroup status and subdivided into three formations: 1) the Union Springs Formation (=lower part of the "Marcellus subgroup"); 2) the Oatka Creek Formation (=upper Marcellus subgroup basinal black shale-dominated facies of western to central New York); and 3) the laterally equivalent Mount Marion Formation (=upper Marcellus subgroup basinal black shale to shoreface sandstone facies of eastern New York). Uppermost Marcellus strata in eastern New York are represented by non-marine, fluvial-dominated sandstones of the Ashokan Formation (Rickard, 1975, 1989).
The transition from the relatively shallow marine carbonates of the Onondaga Formation to clastics of the Marcellus subgroup marks a substantial reorganization of the Devonian Appalachian foreland basin. Major changes in sedimentation, basin geometry, faunas, and paleoecology are associated with overdeepening of the foreland basin due to thrust load induced subsidence (Ettensohn, 1985a) and eustatic sea level rise (Johnson et al., 1985) during a second active tectophase of the Acadian Orogeny (Ettensohn, 1985a).
Apparent extinction of some of the endemic Onondaga faunas and immigration of two successive biotas into the Eastern Americas Realm from Arctic Canada and Europe, respectively, are recorded in rocks of the Marcellus subgroup (Koch, 1988). The first migration is marked by a unique brachiopod and coral fauna found in the newly redefined Union Springs Formation in eastern New York. The first appearance of the classic Hamilton Group fauna occurs in the lower part of the overlying coeval Oatka Creek and Mount Marion Formations across New York. In addition, an important world-wide "extinction-radiation-extinction" bioevent involving pelagic goniatite and dacryoconariid faunas, the Kacak-otomari Event, occurs through this same time interval (Chlupac and Kukal, 1986; Walliser, 1986; Truyols-Massoni et al., 1990).
Analysis of laterally persistent discontinuities and macrofossil "hash" beds within skeletal limestones of the Marcellus subgroup (specifically those in the Bakoven, Hurley (new), and Cherry Valley Members) indicates condensation by short-term events which reworked long-term, time-averaged accumulations. Although the limestones of the Cherry Valley Member comprise distinctly different facies and represent relatively deeper-water deposition, they share a similar origin with younger Hamilton Group limestone members (Griffing, 1994).

A4: STRATIGRAPHY AND FACIES RELATIONSHIPS OF THE EIFELIAN ONONDAGA LIMESTONE (MIDDLE DEVONIAN) IN WESTERN AND WEST CENTRAL NY

Cuts and quarry
Cuts in upper part of highly fossiliferous Penfield Dolostone (Middle Silurian Lockport Group}; Gates quarry in Penfield and Eramosa (Oak Orchard) Formations to left.

Cuts on right and in median in lower sandy dolostone of Penfield Formation.

Outcrops on both sides of highway in upper Penfield and basal Eramosa Formations.

Begin ascent of Onondaga Escarpment.

Camillus Shale (Upper Silurian Salina Group)
Camillus Shale (Upper Silurian Salina Group) cuts on Rte. 19 and adjacent road to right.

Buttermilk Falls
Walk down track to left (east) to Buttermilk Falls of Oatka Creek, a spectacular falls capped by Clarence facies of the Edgecliff Member of the Middle Devonian Onondaga Limestone.
2012: Railroad is gone, but the falls are still here.

Route to the LeRoy Bioherm Quarry
Randall Road, route to the LeRoy Bioherm Quarry, site of one of Sunday's trips (see Wolosz, this volume).

Mill Street on left
Route to Oatka Creek exposure of Onondaga-Marcellus contact.

Bacon Street on left
Route to Oatka Creek exposure of Oatka Creek Formation (type section) and contact with overlying Stafford Limestone of Skaneateles Formation.

Bethany-LeRoy Road on left
Road to classic Middle Devonian Hamilton Group localities.

Berms of quarry visible on left.

STOP 1. GENESEE-LEROY STONE COMPANY QUARRY, STAFFORD.
This relatively large quarry provides an excellent overview of the middle and upper parts of the Onondaga Limestone (Clarence facies of the Edgecliff Member, Nedrow, Moorehouse and Seneca Members; see Figure 5 of Brett and Ver Straeten, this volume). This stop serves as a reference section for western facies of the Onondaga Formation.
The quarry operates in five main lifts. The lowest two are commonly below water level but the second is exposed during drier seasons. Walls of the sump pit below the second lift exhibit heavily cherty Clarence facies of the Edgecliff Member. The overlying platform displays numerous large, spheroidal, chert-replaced heads of Favosites which are overlain by a thin shaly parting. This contact is thought to represent the base of the Nedrow Member at Stafford. It is overlain by an approximately four m-thick interval with distinctly cyclic alternations of dark gray chert-rich micritic limestone and pale pinkish-gray crinoidal limestone with light gray chert and abundant rugose corals.
The next platform is floored by one of the most distinctive marker beds in the western outcrops of the Onondaga; a greenish-gray argillaceous limestone with skeletal hash of crinoids, bryozoans, and brachiopods in addition to abundant and diverse tabulate and rugose corals. Because of its shaly nature, well-preserved fossils are easily obtained from this bed. It is interpreted as a condensed, time-rich fossil bed within the Nedrow Member.
The base of the third lift (5 m high) consists of 1.6 m of dark gray, very cherty, micritic limestone that weathers shaly toward its top and is capped by a 5 cm-thick shale bed. This shale and overlying less cherty, coral-rich, light weathering limestone are also readily correlatable in the Stafford-LeRoy area. The interval is interpreted here as the upper portion of the Nedrow Member. The upper part of the cherty limestone and the 5 cm thick shale are thought to correlate with the lower, thick black shale bed of the upper Nedrow of central New York (Stops 5 & 6). The overlying light-weathering, slightly cherty limestone and succeeding thin shale appear to represent the white limestone and Schizophoria shale bed of the uppermost Nedrow Member as defined herein.
The third lift is capped by another persistent crinoidal hash and coral-rich shaly bed that forms a major platform in the quarry. An old road in the northwest corner of the quarry provides access up to some of the higher beds of the Moorehouse Member. Much of the lower parts of the wall consists of sparsely fossiliferous cherty micritic limestone with dark brownish gray chert. A particularly distinctive bed occurs approximately 1 m below the fourth platform of the quarry. This is a biostrome of thicket-type (fasciculate) rugose corals (Synaptophyllum and/or Eridophyllum). The light-colored corals contrast with surrounding large, dark gray, ellipsoid chert nodules. Slightly higher on the fourth platform, a variety of solitary and colonial rugosans and large favositids are exposed in the quarry floor. This coral-rich interval and immediately overlying crinoidal pack-and grainstones appear to represent the first of two major cycles in the Moorehouse. Slightly above the fourth platform is a distinctly non-cherty, slightly argillaceous and medium gray lime mudstone unit approximately 1.6 m-thick. This unit displays abundant spreiten of Zoophycos (which appear on weathered joint surfaces as gently curved laminae) and thin hash beds of brachiopods. This non-cherty interval weathers with shaly fissility and correlates to a middle Moorehouse shaly, "false Nedrow" interval that occurs widely throughout the Appalachian Basin (see Brett and Ver Straeten, above). It is sharply overlain by coarse-weathering, slightly cherty (pale gray chert) crinoidal pack-and grainstones of the upper Moorehouse, including strata that feature abundant large Paraspirifer brachiopods. This upper 3 m-thick interval comprises the Paraspirifer acuminatus zone recognized by previous workers. It represents the second major shoaling cycle of the Moorehouse. This crinoidal-rich facies yields excellent specimens of the crinoids Arachnocrinus and Schultzicrinus. Two prominent, clay-rich partings in the upper part of the Moorehouse (above the Nedrow-like shaly unit) represent the First and Second Cheektowaga Bentonites (Conkin and Conkin, 1979, 1984; Conkin, 1987; 2.7 and 0.5 m below the base of the Seneca Member, respectively).
Highest beds in the Stafford Quarry are in the Seneca Member of the Onondaga Formation. A distinctive, thick (ca. 20 cm-thick) clay bed that is traceable around the quarry represents the Tioga B or Onondaga Indian Nation Ash Bed that marks the base of the Seneca. The member is comprised of crinoidal wacke-to packstones with a relatively minor number of horizons of large, brownish-weathering chert nodules. The upper beds are exceptionally rich in brachiopods which tend to weather pale-cream to pinkish in color; Leptaena, Megastrophia, Atrypa, and Megakozlowskiella are all abundant here. No upper contact of the Seneca Member has been observed here. However, dredge piles of black shale south of the quarry suggest that the contact with the overlying Marcellus subgroup lies a short distance above the upper platform of the quarry at Stafford.

Cross over Oatka Creek
Falls over Stafford Limestone immediately north
of bridge.

Perry Road on left
Route to 5 or 6 large quarries in the Onondaga
Limestone along Perry Road and adjacent Gulf Road.

Village of Limerock
Site of famous stone fences where paleontologists since James Hall have collected crinoids and other fauna of the Onondaga Formation.

Eastward access to Onondaga quarries along Gulf Road to
north.

Quarry Road on Right
Old quarries in Onondaga down the road.

Descend onto floodplain of the Genesee River.

Junction with Wadsworth Avenue
South to classic Middle Devonian Hamilton Group outcrops.

View of three drumlins to the left (north).

Cross Works Road
Small outcrop of Onondaga Limestone on right along Works Road.

Diagonal joints beautifully exposed in lower Moorehouse to left.

STOP 2a. lower part of Honeoye Falls quarry.
This relatively large and active quarry in the southeastern corner of Monroe County exposes an essentially complete section of the Onondaga Limestone and lower strata of the Marcellus Shale subgroup, including the Cherry Valley Member (see Figure 5 of Brett and Ver Straeten, this volume). Strata in this quarry are slightly deformed (Alleghanian?), and rocks display a gentle dip roughly to the south at a steeper angle than the regional 0.5° dip. Two prominent sets of nearly vertical joints occur in the quarry; the middle portion of the Onondaga also shows a distinctive pattern of diagonal jointing oriented at approximately 080-31 S and 080-50 S. The Honeoye Falls quarry is the only site in the western portion of the state that displays the entire Onondaga Formation (although the Edgecliff Member is only poorly exposed). The Onondaga Limestone at Honeoye Falls is typical of western exposures. The quarry is particularly notable for the unusually coarse facies of the Cherry Valley Member (Oatka Creek Formation) and for the distinctive channeling beneath it that in places chops out nearly the entire Union Springs Formation.
Mining operations work from six main lifts in the Honeoye Falls quarry. The lowest rocks exposed occur in a small, approximately 6.5 m deep sump pit in the northeast portion of the quarry. These rocks are rarely well exposed, commonly covered by water or by a muddy coating. The Upper Silurian (Akron Formation) - Middle Devonian (Onondaga Formation) unconformity is reportedly present in the lower part of the pit (General Crushed Stone Corp. records) although, based on regional trends, we would estimate the contact to lie some meters below. The sides of the small pit are composed of the cherty Clarence facies of the Edgecliff Member. The walls of the overlying larger pit expose a complete section of the Nedrow Member. The base of the Nedrow essentially forms the floor of the large pit in the northeast area of the quarry. Overlying micritic limestones interbedded with more fossiliferous crinoidal wacke-and packstones are characterized by alternating light gray and dark cherts. The middle part of the member features two distinctive subunits; lower, relatively coarse crinoidal pack-to grainstones with scattered corals, somewhat similar to the Jamesville Quarry facies of the Edgecliff Member, and a distinctive interval of greenish-gray argillaceous limestones and green shales 2.8-3.4 m below the Nedrow-Moorehouse Member contact. The green shales are rich in coral and crinoid material, and are correlative with similar strata at the Stafford quarry (Stop 1). The top of the green argillaceous interval occurs at the top of the second wall and forms the base of the third main platform within the quarry, similar to the Stafford quarry. Ellipsoidal and elongate nodular to bedded cherts, which may feature dolomitic rinds, occur scattered throughout generally light gray micrites of the upper Nedrow. A prominent hackly dark chert bed 1.6 m above the green argillaceous interval is probably associated with a prominent, dark to black shale in the upper Nedrow noted widely throughout parts of New York and Pennsylvania.
The Moorehouse Member, as defined herein, begins 2.8 m above the base of the third lift and is relatively thick at this locality (ca. 17 m) Limestones in the lower portion of the member (ca. 5.5 m-thick) appear increasingly fine-grained up to the level of the fourth lift. Nodular chert bands and several layers of bedded, hackly-breaking chert are common. Thin shaly to clay-rich interbeds are also found. Faunal diversity is rather low through the lower part of the Moorehouse.
The middle to upper parts of the Moorehouse at the Honeoye Falls quarry show a general coarsening-up trend. The upper part of the member is generally inaccessible in the high walls of the south face of the quarry, below the Onondaga Indian Nation bentonite (OIN;= Tioga B of Way et al., 1986). Comparison with nearby sections (e.g., Stafford quarry, STOP 1) indicate a rapid coarsening up above a thick, notably more argillaceous unit that occurs above the middle of the Moorehouse (this argillaceous unit is widely recognized across the Appalachian Basin throughout New York and Pennsylvania into at least northern West Virginia; see discussion in Brett and Ver Straeten, above). Where accessible the upper beds of the member are highly fossiliferous and yield well preserved brachiopods and some crinoid crowns (particularly Arachnocrinus) on weathered surfaces. These strata represent the coarsest facies of the upper part of the Onondaga Formation.

STOP 2b. Upper part of Honeoye Falls quarry.
The Tioga B (Onondaga Indian Nations bentonite) forms a prominent break within the quarry at the base of the overlying Seneca Member. The Seneca is characterized by 6.6 m of dominantly tabular wacke-to packstones with minor pale gray cherts. Thin clay-rich partings, most notably at 1.75, 3.05, 3.95, 4.7, and 5.4 m above the base of the Seneca, represent altered volcanic ashes (K-bentonites). The upper bed of the Seneca Member, which consists of relatively coarse crinoidal and brachiopod rich limestone is capped by a sharp lithologic break with the overlying Union Springs Formation.
A thin, mm-scale black shale at the Onondaga-Union Springs contact overlies a relatively minor but widespread submarine unconformity across New York. Overlying strata comprise basal deposits of the Middle Devonian, siliciclastic-dominated Hamilton Group. Recent quarry operations in 1993-1994 have exposed a fascinating cross-section of lower strata of the Marcellus Shale subgroup (see Figure 7 and text of Ver Straeten et al., this volume). The rock exposed comprise the Bakoven and Hurley Members of the newly redefined Union Springs Formation and the Cherry Valley and overlying black shale facies of the also newly redefined Oatka Creek Formation. The Honeoye Falls quarry represents the westernmost known exposure of the Cherry Valley Member and underlying Union Springs strata in New York State (NOTE: terminology used for Marcellus strata above the Onondaga Formation in this field trip guide follows the as yet informal stratigraphic revision presented in Ver Straeten et al., above).
A 15 cm-thick coarse, biotite-rich tuff of the Tioga F bentonite bed immediately overlies the thin skim of black shale at the Seneca-Bakoven Member contact. Overlying thin styliolinid limestones and black, platy, laminated shales of the Bakoven represent deposition under relatively deep, oxygen-starved conditions. A prominent phosphatic fish bone bed that yields abundant conodonts and fish remains, including onychodid teeth and dermal armor of arthrodires (discussed above) occurs within the package of thin limestones above the Tioga F. The Bakoven Member varies in thickness from 7 cm to at least 1.7 m along the outcrop as a result of extensive channeling along the discontinuity surface at the base of the overlying Cherry Valley Limestone.
A relatively thin, light-weathering, richly fossiliferous limestone found toward the eastern part of the Union Springs-Oatka Creek exposures represents the widespread Chestnut Street submember of the new Hurley Member (Union Springs Formation). Pygidia and cephala of the proetid trilobite Dechenella haldemanni are the most diagnostic fossils from this unit. Also present are small to medium-sized brachiopods, auloporid corals, sponge spicules and calyces of the diminutive crinoid Haplocrinites. The upper and lower contacts of this bed are sharply defined.
Along most of the exposure the Chestnut Street submember appears to have been removed; along with varying amounts of the underlying Bakoven Member by an extensive, channeled erosion surface that underlies limestones of the Cherry Valley Member. The Cherry Valley is extremely variable in thickness in this quarry, ranging from just over 40 centimeters upwards to over three meters along 300 meters of outcrop exposed in fall 1993-spring 1994. It is represented a very atypical facies for the unit, which consists dominantly of crinoidal pack-to grainstones with lesser amounts of fenestrate bryozoan and styliolinid material. As previously stated, the basal surface of this unit is extremely irregular and the Cherry Valley appears to fill low spots cut into the underlying Union Springs Formation. In contrast to most other localities, cephalopods are generally not particularly common at this location, although poorly preserved conchs of Agoniatites as well as some orthoconic nautiloids (e.g., Striacoceras) have been obtained. The upper surface of the Cherry Valley Member is also quite sharp and distinct; it commonly appears as a pyrite-coated corrosion surface. It displays an abrupt contact with overlying black shales assignable to the Berne Member.
To date, the highest beds observed in the quarry consist of barren, black, laminated shales with minor styliolinid hash beds. This interval at nearby localities (e.g., bed of Oatka Creek at LeRoy) features a richly fossiliferous bed of brachiopods and small corals that represents the first occurrence of the classic Hamilton Group fauna informally termed the LeRoy bed (=gray bed of Baird and Brett, 1986; see Ver Straeten et al., above); the LeRoy bed has not as yet been found at the Honeoye Falls quarry and likely occurs in strata above the erosional contact of the Oatka Creek Formation with overlying glacial till deposits.
As previously noted, the basal contact of the Cherry Valley Member shows significant paleorelief across the quarry exposure, including distinctive channel-like structures. The cause of the channeling is unknown; in all other localities the Cherry Valley displays a nearly planar, although sharp, basal contact. We presume that the erosional scour was developed as a result of submarine channeling by gradient currents during a relative low stand in sea level. Similar erosional furrowing associated with maximum regression and subsequent earliest transgression has been observed at other localities in younger Middle to Upper Devonian strata (for example, see Brett and Baird, 1990).

Cross Canandaigua Outlet Creek

Manchester quarry in Onondaga Limestone is 1.6 mi. south along Rte. 7.

STOP 3 (Optional). FLINT CREEK. WEST OF PHELPS.
The bed and banks of Flint Creek just west of Phelps provide an excellent exposure of the lower and middle parts of the Nedrow Member in its typical west-central New York facies. The banks expose medium gray, soft, bioturbated mudstones alternating with thin (up to 30 centimeters thick) tabular, somewhat argillaceous, fossiliferous wackestones. Bedding here appears rhythmic and some bundling of limestone beds is evident toward the top of the exposure. The shales near the stream level are extremely rich in well-preserved brachiopods, particularly robust specimens of Pseudoatrypa, Leptaena, and Pentagonia. Scattered crinoid debris and small rugose corals are also present.
The rhythmic bedding within the Nedrow Member may represent minor climatic oscillations. Neither the carbonate nor the mudstones appear to represent major event deposits. The limestone and mudstone bands both consist of multiple beds, some of which may represent thin event deposits, but with bedding largely obscured by bioturbation. Contacts of the interbedded limestones and shales appear to be relatively gradational and generally burrowed by Chondrites traces. Hence the alternations are thought to represent variations in the input of siliciclastic mud. The sharp contrast between of varying siliciclastic content has probably been diagenetically enhanced by early cementation of the more carbonate-rich intervals (discussed in Brett and Ver Straeten, above).

STOP 4. (OPTIONAL) ROADCUT ON NEW YORK ROUTE 88. PHELPS.
Rock cuts on both sides of this north-south road display a Silurian-Devonian carbonate section. Because of the relatively strong component of southward dip, a relatively long section is exposed here. The lower part of the outcrops just south of the New York State Thruway-bridge are in the upper part of the Upper Silurian Bertie Group that display an unconformable contact with the overlying Devonian strata. The unconformity overlies the Scajaquada Formation of the Bertie Group. Medium to slightly reddish gray shales and shaly dolostones display distinct small casts of salt crystal cubes, but few, if any fossils are obtainable from these beds.
The erosional Silurian-Devonian contact at the Wallbridge Unconformity is marked by thin stringers of quartz arenite, apparently of the Lower Devonian Oriskany Sandstone. Thin fissure fillings or neptunian dykes also of Oriskany quartz sand extend 30 to 40 centimeters downward below the upper surface of the Scajaquada Shale. The contact is overlain by a conglomeratic bed containing phosphatic or cherty clasts within a sandy limestone matrix. This bed is only a few centimeters thick, and is overlain conformably by brownish gray-weathering, very cherty micritic limestone (wackestone). Dark bluish-gray chert nodules up to fist size (10 to 20 cm in diameter) occur within these limestone beds. The rock is sparsely fossiliferous, but contains fragments of brachiopods, corals, and echinoderm debris. This unit is clearly not typical of the lower Edgecliff Member of the Onondaga Limestone; it is tentatively assigned to the upper Lower Devonian Bois Blanc Formation. Oliver (1963) reports minor exposures of apparently similar cherty, micritic limestone along the New York State Thruway in the vicinity of Phelps. The contact of the Bois Blanc and the underlying lenses of the Oriskany Sandstone represents a second, post-Wallbridge and pre-Bois Blanc unconformity.
The highest beds exposed in this roadcut consist of pale, pinkish gray-weathering crinoidal grainstone. These strata appear to be in sharp contact on the underlying Bois Blanc and are assignable to the basal Edgecliff Member of the Onondaga Limestone; this contact represent a third sub-Onondaga unconformity. In addition to the abundant crinoid skeletal material, the lower Edgecliff strata contain scattered solitary rugose and tabulate corals. The basal Onondaga contact contrasts markedly with the basal Devonian contact observed in the Oaks Corners (Stop 5} approximately 5 km to the southeast (discussed below).

Outcrops of Upper Silurian Bertie Group.

STOP 5. OAKS CORNERS QUARRY. SOUTH WALL.
The old south wall of the active Oaks Corners quarry displays an excellent section ranging from the basal contact of the Onondaga Formation up through the lower two-thirds of the Moorehouse Member (see Figure 5 of Brett and Ver Straeten, this volume). The quarry can be approached by walking through a narrow strip of field just north of Cross Road at about 0.2 miles west of the junction of Ontario Co. Rte. 6 (Pre-Emption Road). Beds exposed at the level of the field and road are in the upper part of the Edgecliff Member (Clarence cherty facies) near its contact with the Nedrow Member. These flats are some 12-15 m above the base of the quarry. By walking to the left (west) and carefully proceeding down an abandoned quarry road from the upper platform it is possible to examine the lower part of the Onondaga down to the contact of the Edgecliff Member with the underlying Upper Silurian strata.
At the Oaks Corners quarry, in contrast to the Route 88 roadcuts (Stop 3), the Onondaga Limestone generally rests directly on beds of the Upper Silurian Akron Formation, a massive, dark brownish buff-weathering saccharoidal dolostone. J.W. Scatterday (personal commun.) reports a thin, locally-occurring sandstone in part of the quarry similar to that seen at Stop 4; it is presently unknown whether these strata are related to Oriskany or Tristates Group sandstones ("Springvale"). Where the sandstones are absent, the Akron-Onondaga contact is typically marked by rust staining, as a result of weathering of pyritic crusts that occur along the erosional surface. The unconformity is approximately four to five meters higher in the Silurian section than at the Rte. 88 exposures (Stop 3), where the unconformity surface is cut down to the level of the older Scajaquada Shale. In the Oaks Corners quarry, the unconformity displays relief of up to one meter. Large channel-like depressions, up to several meters across, occur along this boundary. Again, in contrast to the Route 88 cuts, where possibly four to five meters of Bois Blanc Formation occur above the unconformity, the Bois Blanc is missing at this location and the basal beds of the Edgecliff Member occur within hollows on the combined Wallbridge, sub-Bois Blanc (?), and sub-Onondaga unconformities.
The lowest unit of the Edgecliff Member is a fine-to medium-grained crinoidal grainstone, typically pinkish-weathering, which ranges from 40 to 120 centimeters in thickness as a result of the irregular topography at its base. The transition to chert-rich strata (Clarence facies) is abrupt but gradational and consists of cherty, crinoidal pack-to wackestones. The remainder of the Edgecliff Member is dominated by the Clarence cherty facies, and consists predominantly of pale gray-weathering micritic limestone with 20 to 30% dark gray chert. Skeletal wacke-and packstones, which feature large crinoid columns and tabulate and rugose corals, occur approximately three and six meters above the base. These form two light pinkish gray-weathering bands in the wall of the quarry and thus constitute important markers as well as represent the apparent tops of minor shallowing-up cycles. A 46 cm-thick, medium dark gray, sparsely fossiliferous and very calcareous shale occurs high in the Edgecliff Member. This interval closely resembles the higher Nedrow Member, but it is separated from the latter unit by 1.2 meters of micritic cherty limestone typical of Clarence facies. The Edgecliff is approximately 8.5 m-thick at the Oaks Corners quarry.
A sharp limestone-shale contact at the top of the Edgecliff marks the base of the Nedrow Member. Lowest shales of the Nedrow contain a relatively abundant fauna of Pseudoatrypa, Leptaena, small rugose corals, and other fossils. The Nedrow Member itself is approximately 5.3 m-thick at this location and consists of medium to dark gray, very calcareous shale or mudstone that alternate with argillaceous lime mudstones or wackestones. Some of the rhythmic bedding and bundling of limestones observed along Flint Creek in the corresponding interval (STOP 2) is also apparent here, although somewhat more subtle in this outcrop. The upper portion of the Nedrow Member contains a distinctive dark gray to black shale interval with small black chert nodules. This black shale marker bed has proved to be very widespread across the Appalachian Basin and is recognized at present across parts of New York to southern Pennsylvania (see above). A 40 cm-thick, light-weathering limestone bed with minor pyrite separates this bed from an overlying brownish-gray shale interval that contains a thin nodular limestone bed rich in the brachiopod Schizophoria sp. This bed forms the floor of the second highest lift near the abandoned quarry access road along the south wall of the quarry, where the brachiopod fauna and spectacularly weathered Chondrites burrows can be observed.
The Moorehouse Member in the Oaks Corners quarry consists dominantly of medium-to thick-bedded micritic limestones (slightly argillaceous fossiliferous wackestones). Several intervals of medium to dark gray chert occur within this section. Particularly heavy cherty beds occur approximately four to five meters above the base of the Moorehouse. Thin intervals of medium to dark gray, very calcareous shale that closely resemble the Nedrow Member (particularly the Schizophoria bed) occur approximately 2.2 and 3.0 m above the base of the Moorehouse. A relatively thick calcareous shale (80 cm thick) that features well-preserved specimens of Pacificocoelia as well as Schizophoria occurs 5.4 m above the base of the Moorehouse and is well displayed in a cut along the side of a second, more westerly abandoned roadway that leads into the quarry along the south side. A cherty micritic limestone bed approximately 1.5 m below the Pacificocoelia shale contains abundant coiled nautiloid cephalopods (Gyroceras) which are well displayed on a glacially polished surface just east of the second access road.
Highest beds of the Moorehouse are quite fossiliferous, and are particularly rich in brachiopods. Argillaceous beds about one meter below the top of the quarry contain a fauna dominated by atrypids and other brachiopods such as Megakozlowskiella, Leptaena, Schizophoria, and others. Trilobite material is rather common in the upper shaly beds and includes specimens of Phacops and Odontocephalus. Echinoderm material is relatively sparse, although rare specimens of an undescribed stalked rhenopyrgid edrioasteroid have been obtained from the shaly beds. Overall, the Moorehouse appears to have at least four to five minor shallowing-up cycles, each of which commences with calcareous shales and culminates in more massive, cherty, micritic limestones that may contain corals such as Acinophyllum. The upper part of the Moorehouse Member and the entire Seneca Member are absent at this location due to post-Devonian erosion.
The lower part of the Onondaga Formation at Oaks Corners is similar to more western sections in that the Edgecliff Member is dominated by Clarence cherty facies. Only a relatively small proportion (approximately 10% of the member) consists of the more classic chert-poor crinoidal packstones characteristic of the Jamesville Quarry facies (see body of paper) of the Edgecliff. The remainder of the member is relatively cherty, although not as chert-rich as the Clarence in Erie and Genesee counties. The Edgecliff here (ca. 8.5 m-thick) contrasts markedly with that seen at the Seneca Stone quarry (STOP 5; 21 km southeast) where the member is quite thin (< 3 m-thick) and consists mainly of the crinoidal wackestone facies with only a single band of cherty micritic limestone (see stop description below). The Nedrow Member at Oaks Corners is considerably shalier and less fossiliferous than the equivalent beds seen at the Honeoye Falls quarry (STOP 1; 50 km west) where the member is composed of micritic limestones with light gray to dark chert and greenish-gray argillaceous limestones rich in a diverse assemblage of rugose and tabulate corals, gastropods, brachiopods and other fossils. At the Oaks Corners quarry the Nedrow is only sparsely fossiliferous and carries a fauna dominated by a few species of brachiopods. Moreover, the upper portion of the member contains the distinctive black marker bed, which in the Stafford and Honeoye Falls quarries (STOPS 1 & 2) appears to be represented by fossiliferous greenish shales. The Nedrow interval at Oaks Corners is, on the other hand, quite similar to that seen at Seneca Stone quarry (STOP 5).
The Moorehouse Member at Oaks Corners displays features suggestive of an intermediate setting between those seen in the Honeoye Falls and Seneca Stone quarries (STOPS 1 & 5). It is thicker, more chert-rich, and more fossiliferous than the equivalent interval at Seneca Stone quarry. However, it contains considerably less crinoid material and is dominated by brachiopod-rich wackestone lithologies as opposed to the crinoidal wacke-and packstones of the Moorehouse at the Honeoye Falls quarry. It carries a fauna rich in brachiopods assignable to the Megakozlowskiella, Atrypa, and Pacificocoelia communities recognized by Feldman (1980).
Overall, the Onondaga appears to be uniformly of more fine-grained, more argillaceous, and probably deeper water facies than those seen in the corresponding intervals at and to the west of the Honeoye Falls quarry (STOP 1). However, the relationship of facies to those of the Seneca Stone quarry is not so clear cut. The lower Edgecliff Member appears to be distinctly finer-grained, more cherty, and less fossiliferous than the equivalent strata at Seneca Stone quarry. We suggest that only the upper beds of the Edgecliff at Oaks Corners quarry are continuous into the Seneca Stone quarry, where the lower units have pinched out over the irregular topography below the combined Wallbridge and sub-Onondaga unconformities. Those upper Edgecliff beds show distinct facies changes between Oaks Corners and the Seneca Stone quarry 21 km to the southeast. In particular, the chert-rich intervals appear to grade southeastward into crinoidal wacke-and packstones, whereas the dark gray Nedrow-like shale interval approximately 7.3 m above the base of the Edgecliff appears to grade into a single chert-rich micritic bed at the Seneca Stone quarry. Hence, it would appear that the Edgecliff Member is uniformly of deeper water character at Oaks Corners than at Seneca Stone quarry, which suggests a more basinal setting to the west at that time. The Nedrow Member appears very similar at both localities. The Moorehouse Member, in total contrast, appears to represent distinctly shallower water facies at the Oaks Corners quarry than it does at the Seneca Stone quarry, a complete reversal of the trend seen in the Edgecliff Member. This suggests that the basin axis or center of subsidence shifted through time from a more westerly position (probably west of Oaks Corners) eastward to the vicinity of the Seneca Stone quarry during deposition of the Onondaga Limestone.

Large gravel pit on left.

Bridge over Seneca River

STOP 6. SENECA STONE QUARRY.
The Seneca Stone quarry is another relatively large quarry that exposes a complete section from the upper part of the Lower Devonian Manlius Limestone to the top of the Middle Devonian Cherry Valley Member of the Oatka Creek Formation (Marcellus subgroup; see section in Brett and Ver Straeten, this volume, Figure 5). Strata within the quarry generally appear undeformed, with the exception of a prominent north-directed thrust fault that cuts up through the upper part of the Onondaga Formation (visible in the southeast and southwest parts of the quarry).
Limestones of the Lower Devonian Manlius Formation (Helderberg Group} are found in a small sump pit in the bottom of the quarry, overlain unconformably by quartz arenites of the Lower Devonian Oriskany Formation (lower part of the Tristates Group). These two units are separated by the true Wallbridge Unconformity that marks the base of the Kaskaskia Megasequence. Clasts of the older Manlius Limestone are visible in the base of the Oriskany, where they may be overgrown by tabulate coral colonies. The white quartz arenites of the Oriskany Sandstone also feature numerous large, robust brachiopods (including Costispirifer arenosus, Rensselaeria, and Hipparionyx), platyceratid gastropods, and rare rugose corals.
Twenty-five km northeast of the Seneca Stone quarry, at Auburn, sand-dominated strata of the upper part of the Tristates Group (Carlisle Center and Schoharie Formations) are present, similar to strata reported for the Syracuse area (see Brett and Ver Straeten, above). At Seneca Stone quarry, however, these rocks are absent except as reworked phosphatic cobbles in a basal sandstone bed of the Edgecliff Member (Onondaga Formation). Reworked, phosphatized clasts of the Manlius and Oriskany Formations are also found in the basal Edgecliff sandstone bed. A thin interval of coral-rich limestone is succeeded by two cyclic packages of Edgecliff strata that appear to be equivalent to the two upper Edgecliff cycles seen at Oaks Corners (STOP 5). Well developed fine-grained, cherty Clarence facies are only developed within the lower part of the second cycle at Seneca Stone; the Edgecliff member in general here appears coarser than equivalent strata at Oaks Corners (STOP 5).
A sharp change into overlying calcareous dark shale-dominated strata marks the base of the Nedrow Member. The Nedrow and lower to middle parts of the overlying Moorehouse Member are best exposed in the east wall of the quarry below the third platform. The lower part of the Nedrow consists of alternating dark shales and argillaceous wackestones. Several distinctive crevices within the middle to upper Nedrow here may represent altered volcanic ash beds. The distinctive "black bed" in the upper Nedrow, which at Seneca Stone quarry consists of black shale with several bands of black chert nodules, is highly visible in the eastern wall. The bed, as observed at the previous locality (STOP 5), is overlain by a light weathering limestone and the dark "Schizophoria bed" at the top of the Nedrow. Overlying strata assigned to the lower part of the Moorehouse Member consist of alternating calcisiltite limestone beds (<1 m-thick) interbedded with thin (ca. 5-15 cm thick) calcareous shales. This interval is relatively similar to facies that characterize the Onondaga-equivalent Selinsgrove Limestone of central Pennsylvania. Two paired crevices approximately 0.9 and 1.0 m above the Schizophoria bed represent apparent K-bentonite beds that are widely traceable across the central part of the Appalachian Basin (see Brett and Ver Straeten, above). Quartz pebbles and granules have been noted in a 14 cm-thick calcareous shale bed 2.5 m above the base of the Moorehouse. A 45 cm-thick argillaceous unit 6 m up in the Moorehouse, just below a platform on the east wall, correlates with the prominent "false Nedrow" shale seen at Stafford (STOP 1) and other localities across much of the Appalachian Basin (see Brett and Ver Straeten, above).
More resistant, coarsening-up strata of the upper Moorehouse Member Form the wall of the lift above the Nedrow-like shale unit up to the thick Tioga B-OIN Bentonite bed at the base of the overlying Seneca Member. Two conspicuous crevices, which feature biotite-rich claystones, represent the First and Second Cheektowaga Bentonites of Conkin and Conkin, (1979, 1984; Conkin, 1987). A 10 cm-thick, dark chert bed forms the cap of the 9.8 m thick Moorehouse Member at Seneca Stone, immediately below the Tioga B-OIN bentonite bed.
The Seneca Member represents a general fining-up trend from the relatively coarse upper part of the Moorehouse Member. The Tioga B-OIN bentonite marks the base of the member. Five and possibly seven additional bentonites occur within the Seneca Member and the base of the overlying Union Springs Formation at Seneca Stone. Two fining-to coarsening-up cycles within the Seneca represent relatively smaller scale cycles superimposed on the general deepening-up trend (see Brett and Ver Straeten, above). Lithology of the member ranges from poorly fossiliferous wackestones to low diversity brachiopod-rich packstones (e.g., "Pink Hallinetes (formerly Chonetes) Zone," 3.2-4.0 m above the base). Nodular cherts and impure dolomitic cherts occur scattered throughout the member. The Seneca Member, as defined herein, totals 7.15 m in thickness. The upper contact of the Seneca Member at Seneca Stone quarry as defined herein is marked by a distinctive bedding plane with large horizontal burrows, scattered fish debris, and some pinkish weathering, apparently hematitic, limestone "clasts." The bed is immediately overlain by eight cm of black shale and a thin (3 cm-thick) k-bentonite bed. Overlying dark, fine-grained, styliolinid limestone beds are assigned herein to the Bakoven Member of the Union Springs Formation. The prominent, rusty-weathering Tioga F bentonite (ca. 12 cm-thick) occurs 65 cm above the base of the Bakoven at Seneca Stone. The lower 1.3 m of the Bakoven is dominated by the previously mentioned thin styliolinid limestone beds. Black shales become more prevalent above, but occur interbedded with numerous thin (ca. 2-20 cm-thick) micritic limestone beds. The top of the Union Springs Formation at Seneca Stone quarry is represented by the richly fossiliferous Chestnut Street submember of the Hurley Member. The Chestnut Street beds, with their characteristic lighter-weathering color and fauna (e.g., proetid trilobites and the microcrinoid Haplocrinites clio), form a thin ledge of limestone approximately 10 cm in thickness that is firmly welded to the base of the overlying Cherry Valley Member (Oatka Creek Formation).
The Cherry Valley Member at Seneca Stone is more typical of its occurrence along much of its outcrop west of the Albany area. Three subdivisions, a lower massive, middle nodular, and upper massive limestones comprise an approximately 50 cm-thick section of organic-rich, pyritic, bedded to nodular wacke-to packstones. The classic goniatite and nautiloid cephalopod fauna of the Cherry Valley, which includes Agoniatites vanuxemi and Striacoceras typum, is well displayed on the excellently exposed upper bedding plane seen above the south wall of the quarry. Truncated cephalopod shells, fish bone material, and scattered pebbles, along with the development of a firm-to incipient hard-ground and pyritic crusts on the upper surface of the Cherry Valley Member, indicate a period of submarine sediment starvation prior to deposition of overlying shales. Overlying strata are not at present exposed, but Baird and Brett (1986) report dark shales that include a distinctive bed (LeRoy bed=gray bed of Baird and Brett, 1986; see Ver Straeten et al., above) in which the classic fauna of the Middle Devonian Hamilton Group makes its first appearance in the Appalachian Basin.

A5: FRASNIAN (UPPER DEVONIAN) STRATA OF THE GENESEE RIVER VALLEY, WESTERN NY
WILLIAM T. KIRCHGASSER
SUNY-Potsdam
Potsdam, New York 13676
D. JEFFREY OVER
SUNY-Geneseo
Geneseo, New York 14454
DONALD L. WOODROW
Department of Geoscience
Hobart and William Smith Colleges
Geneva, New York 14456
History of Investigation
The Frasnian section in the Genesee Valley is located in the western part of the central Devonian outcrop belt of New York State that stretches from the Catskill Mountains to Lake Erie. The Genesee Valley was close to the center of the Fourth Geologic District of the first state survey, the district between Cayuga Lake and Lake Erie, covered by James Hall. Hall's final report, the monumental Part IV of the Geology of New York (Hall, 1843), is the starting point for Devonian studies in the region (Figure 1). The rocks of the classical Genesee, Portage and Chemung divisions consist of a succession of marine siliciclastics beginning with dark basinal shales (Genesee) that contain a pelagic molluscan fauna, which are overlain by lighter colored shales and siltstones that contain a pelagic and benthic fauna (Portage and Naples to the east) that were deposited in basin-and-slope environments. These strata are overlain by siltstones and sandstones bearing a benthic brachiopod fauna (Chemung) that were deposited on the slope and outer shelf. Most of the fossils in these units were described in monographs by Hall (1879) and Clarke (1899, 1904). The excellent exposures in the Genesee Valley made this section a center for geological studies of the distal rocks of the Catskill Delta, which record stages in the filling of the Appalachian Foreland Basin. Beginning with Hall's (1843) observation of the lateral changes in lithology within each division ("constant increase of arenaceous matter" to the east and "increase in mud or shale" to the west) the Genesee Valley section came to play a central role in the application of the facies concept to the Appalachian Devonian.

A5: FRASNIAN (UPPER DEVONIAN) STRATA OF THE GENESEE RIVER VALLEY, WESTERN NY

Retsof mine collapse
The highway was closed in March 1994 due to road and bridge damage west of the Genesee River near Cuylerville that resulted from roof collapse of the Retsof salt mine and subsequent subsidence and formation of sink holes. The salt beds are approximately 300 m (1,000 ft) below the valley floor in the Upper Silurian Vernon Formation.

STOP 1A. Fall Brook
(Property is posted, access by permission only.)
Erosional base of Genesee Group, pyritic lag, dark colored petroliferous shales, interbedded carbonates, Givetian-Frasnian boundary, and major deepening of the basin represented by planktic-fauna carbonates. Leicester Pyrite, Geneseo Shale, Penn Yan Shale, Genundewa Limestone.
Strata of the Moscow Formation (Hamilton Group) are exposed in the stream bed and banks below the falls. Fossiliferous bluish-gray shales of the Kashong Member are overlain by bioturbated fossiliferous medium gray calcareous shales and carbonate beds of the Windom Member (Figure 10). The steep banks prevent close investigation of Genesee strata. Stratigraphic relationships and fallen debris can be examined in the gorge, in place collections can be made from a side creek or STOPS 1B (Dewey Hill) and 1C (above falls) where strata are more accessible. Caution: large blocks have been known to fall from overhangs and strike eminent geologists.
The Genesee Group consists of the Leicester Pyrite, Geneseo Shale, Penn Yan Shale, Genundewa Limestone (resistant bed forming falls), and West River Shale. The base of the Genesee Group is marked by the Leicester Pyrite, a 0-20 cm thick sharp based accumulation composed almost entirely of pyrite nodules, pyritized burrows, and pyrite replaced fossils that represents a condensed lag accumulation above a major disconformity. The bed contains a mixed conodont and cephalopod fauna of Hamilton, Tully, and Genesee nature (Figure 5). The unconformity is the result of submarine erosion, corresponding to the Taghanic Onlap (Baird and Brett, 1986a). Look for pyritized cephalopods (Tornoceras uniangulare), crinoids, bivalves, burrow fills and rare brachiopods and trilobites in fallen blocks of the Leicester, which is distinctive due to the orange-brown weathered surface.
The Geneseo Shale gradationally overlies or is locally interbedded with the Leicester Pyrite. Here at Fall Brook the Geneseo is 8.2 m thick (base of lower black shale to top of upper black shale), characterized by a lower 1.7 m thick and an upper 1.4 m thick dense black petroliferous shale units separated by 5 m of medium-dark gray shale and thin carbonate mudstone beds. [In deWitt and Colton (1978) only the lower black shale is considered to be the Geneseo.] The Geneseo black shale thickens eastward, absent at Lake Erie (possibly represented as a parting between the North Evans Limestone and Genundewa Limestone) to about 30 m thick in the Finger Lakes (Figure 2).
The continuous limestone band in about the middle of the gray Geneseo shale interval is the Genesee Limestone (GL), with Pharciceras and a disparalis Zone conodont fauna that includes Polygnathus linguliformis gamma and Po. dubius. The Fir Tree Limestone, represented here by a thin carbonate mudstone bed 1.2 m above the Genesee Limestone, is a distinctive horizon in the Finger Lakes region that contains a pyrite-bone bed lag developed on the corroded surface of a carbonate bed (Baird et al., 1989).
The Penn Yan Shale lies above the upper thick black shale of the Geneseo and is characterized by medium-dark shale and interbedded thin carbonate mudstones, styliolinid packstone/grainstones, and thin black shale beds. The Lodi Limestone, a nodular carbonate 1.1 m above the base of the Penn Yan, marks the local first occurrence of Ponticeras perlatum and Skeletognathus norrisi, indicative of the norrisi Zone, the latest zone of the Givetian. Ancyrodella rotundiloba early form, which defines the base of the Frasnian and MN Zone 1 of Klapper (1989), and the Givetian-Frasnian boundary, occurs just above the Lodi Limestone east of the Genesee Valley (Figure 3, 5). Based on graphic correlation with the Frasnian Composite Standard of Klapper et al. (1993), however, the Givetian-Frasnian boundary would lie in the Geneseo-Penn Yan transition (Figure 6). The Lodi Limestone can be collected from the side creek, and will also be seen at Dewey Hill (Stop 1B).
The Genundewa Limestone caps the water fall of Fall Brook. The Genundewa is a 0.3 to 0.5 m thick, wood-bearing, cephalopod styliolinid packstone-grainstone that consists of several amalgamated beds separated by discontinuous shale laminae. The grainstone consists almost entirely of the small conical shells of Styliolina fissurella, an enigmatic organism that may be a protist (Yochelson and Lindemann, 1986). The lower surface is irregular, indicating scouring of the sea floor prior to or during deposition. Reworking and erosion are indicated by current alignment of the styliolinids and corrosion/wear features. The Genundewa is interpreted as the result of deepening of the basin; consequent flooding of the terrigenous sediment source and near shore sediment trapping resulted in accumulation of planktic organisms, without dilution by siliciclastics. Several styliolinid laminae and thicker packstone-grainstones occur in the upper Penn Yan indicating cyclic deepening and consequent sediment starvation. The base of the Genundewa is recognized by a regionally persistent, thin (10 cm) black shale bed that underlies the prominent carbonate band. The Genundewa will be viewed in place at STOP 1C; however, samples can be easily collected from large slabs in the stream bed.

STOP 1B. Dewey Hill: Penn Yan Shale including Lodi Limestone Member, SB bed, and Linden Horizon.
Pull off and park before guard rail on right. Exposures are in ditch and cuts on both sides of the road; the section described is on the south side.
Here we will be able to closely examine beds below the Genundewa Limestone in the side walls of Fall Brook at Stop 1A. The Penn Yan Shale is comprised of dark to medium gray shale with interbedded carbonate and black shale. The Lodi Limestone, exposed in the road ditch, is the lowest key bed. The Lodi consists of thin (5 cm) discontinuous beds and nodules that are traceable to the Finger Lakes region and represents the latest Givetian (Middle Devonian) in New York State; Ponticeras is the predominant goniatite, but it is rare this far west. The Givetian-Frasnian (Middle-Upper Devonian boundary) is taken as the base of the shales overlying the Lodi, recognized by the first occurrence of Ancyrodella rotundiloba early form, which is used to define the base of MN Zone 1 (lowest Frasnian). Gastropods and rhynconellid brachiopods may be found in the nodular Lodi at this locality.
The SB bed is a 20 cm thick distinctive black shale interval that is characterized by a conodont and lingulid lag horizon in the lower few centimeters. The horizon interval represents a phase of benthic anoxia-dysoxia with preservation of organic material, as well as a hiatus/erosion surface and concentration of phosphatic bioclasts. Conodonts of MN Zone 1 can be recovered from the shale.
In contrast to the larger scale sequence marked by the disconformity at the base of the Genesee Group, smaller scale sequences in the Geneseo, Penn Yan, Genundewa, and West River formations (basin facies) seem symmetrical, preserving sediments that represent both the deepening and shallowing without development of a pronounced hiatus. The SB phosphate lag is an example of a cryptic disconformity within a minor cycle that marks a deepening maxima phase in the basin.
Nodular and continuous carbonate beds in the middle-upper Penn Yan contain cephalopods (genera include Koenenites, Acanthoclymenia, and Tornoceras) and conodonts. The key styliolinid bed is the Linden Horizon (LH) that contains Koenenites styliophilus. In this horizon the goniatite shells are often filled with crystalline pink and white barite. This level marks the base of MN Zone 2 in New York (Ancyrodella rotundiloba late form).

STOP 1C. Fall Brook above falls: Genundewa Limestone and West River Shale.
Extreme Caution: the edge of the Genundewa is unmarked and the drop to the base of the falls is over 100 feet.
The Genundewa Limestone consists of approximately 35 cm of several amalgamated beds of styliolinid grainstones separated by discontinuous shale partings that can be traced from Lake Erie to Keuka Lake. The base of the Genundewa is marked by a persistent black shale bed that separates it from carbonate beds in the upper Penn Yan. Note here the irregular contacts in the Genundewa and proximal strata and apparent rippled surfaces. The styliolinids are aligned, indicating current orientation, however, the nature of the current(s) responsible is enigmatic: contourites, waves on pycnocline boundaries, storm waves, ocean gyres, or density currents are possible mechanisms.
The upper and lower Genundewa contain distinctive faunas. The lower beds are characterized by Ancyrodella rotundiloba late form, indicative of MN Zone 2. The upper Genundewa contains the first appearance of Manticoceras and conodonts of MN Zone 3, including Ad. rugosa, Ad. alata, and Ad. sp. B (Kralik, in press; Figures 3, 6).
The lower West River Shale is exposed in the creek bed and banks above the falls. The West River Shale consists of dark to medium gray shales and thin carbonate beds, lithologically similar to the Penn Yan Shale, that indicate shallowing and a return to fine clastic sedimentation following Genundewa deposition. A thin (3 cm) styliolinid carbonate bed approximately 2 m above the base of the shale contains numerous conodonts of MN Zone 3 [USGS SilurianDevonian cat. No. 8122SD (Huddle, 1981 )]. The upper West River Shale is exposed at the base of the Mt. Morris Dam at STOP 2.

STOP 2. Mt. Morris Dam
(access by permission from US Corps of Army Engineers)
Gorge overlook: dark gray shale of upper West River Shale at base above and below dam (river level); black shale of Middlesex Shale and green/gray shale of Cashaqua Shale, Sonyea Group; and gray/black shale of Rhinestreet Shale, lower West Falls Group to the top of the exposure (Figure 11). An apparent correlative of the Belpre Ash Bed may be visible.
Exposures are along the dam access road and "Burma Road" that descends gorge wall upstream from dam.
The Letchworth Gorge of the Genesee River is a Pleistocene hanging valley cut into shales, siltstones, and sandstones of the Genesee, Sonyea, and West Falls groups. Three main waterfalls in the upper gorge are formed on resistant sandstones of the upper West Falls Group. The section exposed at the dam includes gray shale of upper West River Shale at the base above and below the dam (river level); black Middlesex Shale and green/gray Cashaqua Shale, Sonyea Group; and gray/black Rhinestreet Shale, lower West Falls Group up to the top of exposure. The two black shales represent major transgressions.
The lower Rhinestreet Shale and upper Cashaqua Shale are exposed in the access road to the top of the dam. The Cashaqua consists of green-gray shale and mudstone that are darker at the base, lighter colored and highly bioturbated in the middle, and darker gray at the top. This lithologic change indicates a shallowing cycle, superimposed on which there are numerous shorter-duration cycles indicated by darker shale bands and concretionary horizons. The medium gray shale of the upper Cashaqua exposed at the dam contains numerous bivalves and coalified plant fragments. The prominent concretionary band in the upper Cashaqua is the Shurtleff Septarian Horizon. These concretions contain a diverse conodont fauna of MN Zone 6 (Palmatolepis punctata, Ancyrodella nodosa), as well as mollusks replaced or filled with pink or white barite, including the goniatites Manticoceras sinuosum and Prochorites alveolatus (Figure 7; House and Kirchgasser, 1993).
The base of the Rhinestreet Shale and the West Falls Group is marked by a sharp transition from medium-to-dark gray shale below to thick black shale. The Rhinestreet is the thickest and most widely distributed black shale bed in the Upper Devonian of New York and represents a major transgression and deepening (Figures 2, 8). Plant remains, rare cephalopods, conodonts, and other fossils can be recovered from bedding planes.
If time and weather permits the entire Cashaqua can be accessed on the "Burma Road" which enters the gorge upstream of the dam. If pool level is low the upper West River and Middlesex may also be exposed, however, out-croppings are likely to be partially covered by mud and debris. The base of the Cashaqua denotes the start of MN Zone 5 (Palmatolepis punctata) and Probeloceras lutheri Zone. A diverse molluscan fauna can be recovered from the greenish shales, including Probeloceras lutheri and numerous bivalves; among the most common are Buchiola, Ontaria, and Pterochaenia (see Clark, 1904).

STOP 3. I-390 Mile 32: slope-basin muds and turbidites of Gardeau Shale, West Falls Group.
Pull off shoulder and park at Mile Marker 32, exposures are in road cut on both sides of highway; measured section is on the west side of the southbound lane.
In the gorge section, the Gardeau Shale overlies the Rhinestreet and extends upstream to the Middle Falls, consisting of approximately 100 m of interbedded green-gray shale, black shale, and silts that represent an influx of fine and coarse clastic material into the basin. The exposure here of the Gardeau Shale consists of interbedded medium gray and dark shales that may represent small scale cycles that are overlain by interbedded silty shales and thin silt-sandstones that may also represent small scale cycles (Figure 12). The shales have yielded a low diversity and sparse fauna of nowakiids. Inarticulate brachiopods and trace fossils occur in the coarser (silt-sandstone) beds. The brachiopods and trace fossils in the silt-sandstone beds indicate development of dysoxic-oxygenated benthic waters and a suitable substrate for benthos. The silt-sandstones are graded, consisting of a scoured base, massive lower sand, and ripple to hummocky cross-laminated upper surfaces that are sharply overlain by gray shale. Scour features on the bases of silt-sandstone beds are oriented east-west. Many of the scours are laterally asymmetric, possibly the result of helical flow of the scouring current. The silt-sandstones are interpreted as turbidites, however, the upper surfaces have been reworked by subsequent currents.

STOP 4. I-390 Between Mile Markers 15 and 14
Shelf sands of upper West Falls Group, Nunda or Wiscoy sandstone; ichnofossils, channel sand and shell-rich basal channel fill.
High exposures on both sides of road between mile markers 15 and 14, pull well off shoulder at southern end of the exposures near the crest of the hill and park.
These sandstone exposures are questionably of the Nunda Sandstone which represents the upper West Falls Group and coarse-grained lateral equivalent of the Angola Shale in the Genesee River Valley. The sandstones are composed of tabular to lenticular thin to medium beds. Brown weathering sands are muddier, often low angle cross-laminated, and may contain rip-up clasts of brown mudstone and plant fragments. Medium blue-gray sands are ripple surfaced and cross-laminated, locally bioclastic (bivalves, brachiopods, and crinoids), and moderately to completely bioturbated. Identifiable trace fossils include Skolithos, Diplocraterion, Scalarituba?, and small Chondrites?, as well as poorly preserved lined and unlined horizontal to subhorizontal burrows. These sands are similar to the bluestones that were a common quarry stone near Portageville at the head of the Genesee gorge in the 1800's and early 1900's. Also notable in the section are resistant spherical weathering zones, suggestive of concretions developed in the sandstone.
In the southern most outcrop of the south bound lane is a channel cut filled with light gray weathering sandstone. The base of the channel consists of a 40 m long, 0.4 - 0.7 m thick dark-brown weathering fossiliferous sandstone to sandy carbonate. The stratum contains numerous brachiopods of a deep shelf environment (Cyrtospirifer, Douvillina, Nervostrophia, Spinatrypa), as well as cephalopods, crinoids, fish remains, and a diverse polygnathid conodont fauna. The fauna is characteristic of MN Zone 12.
The current reworked and bioturbated sands, brachiopod fauna, Skolithos-Curziana ichnofacies, and polygnathid conodont fauna are indicative of a moderate energy shelf environment. These sands correlate to finer grained green-gray and dark gray shale of the Angola to the west (Figure 2). The Pipe Creek Shale, a thin transgressive black shale unit, separates the Nunda from the overlying Wiscoy Sandstone, the lateral equivalent of the Hanover Shale (highest Frasnian). The Pipe Creek is not well developed in this region and has not been locally identified. More nearshore channel and deltaic sandstones are found to the south in Famennian strata. These shallow water shelf and near shore sandstones record the late stages of progradation of the Catskill Delta across New York State and the filling of the Appalachian Foreland Basin.

B1: LAND INSTABILITY IN THE GENESEE RIVER VALLEY-LIVINGSTON COUNTY
Lawrence Lundgren and Weiyang James Wang
Land instability in the Genesee River Valley in Livingston County takes three forms: River-bank failure during meander migration, landsliding, and subsidence over abandoned salt mine workings. River-bank failure is a completely natural process possibly influenced by controlled discharge from the U.S. Army Corps of Engineers Mount Morris Dam in Letchworth State Park. Landsliding is a natural process along the Genesee River. Subsidence over abandoned salt-mine workings is a process induced by mine collapse. Only the subsidence stop (1) and the meander migration stop (2) will actually be visited on this trip.

B1: LAND INSTABILITY IN THE GENESEE RIVER VALLEY-LIVINGSTON COUNTY

STOP 1. Wang sites SE-01-88 and SE-02-88
Note that these sites are only accessible with permission of the land owner. They may or may not be accessible at the time of the NYSGA field trip. If they are not, then they will be viewed from the parking area at the New York State Historic marker site.
Discussion topics: ( 1) The inception of slope instability on previously stable forested slopes. (2) The initial removal of the soil-zone slab. (3) Interaction among different types of slope failure.
These sites are the key to our interpretation of slope instability and evolution. Landslides have been evolving dramatically in the 6 years since observations were begun by Wang.
The pre-landslide character of the slopes at this site is evident from the still vegetated slopes around and above the active landslides on the east side of the bay. Oak, maple, poplar, and other large trees are rooted in the meter-thick soil blanket developed on slopes as steep as 40°. Up to 1951, the entire slope at this site was stable and completely covered by bushes and trees, many of them 50 years old or older. The slope first became unstable sometime between 1953 and 1960.
In 1988, when Wang made his first observations, multiple landslides were already evident (Figure 3). Figure 3 illustrates what we infer to be the initial stages in the destabilization processes affecting Irondequoit Bay slopes. The meter-high scarp surrounding the landslide complex reveals a meter-thick soil zone. Initial slope failure entailed the downslope movement of slabs the base of which is approximately the base of the soil zone. This slab carried with it all of the trees rooted in the soil zone. Even large oak trees have been transported down slope while initially remaining in upright position. Slab A began to move down slope in April 1990 to the position shown in April 1993.
This initial movement of the soil-zone slab effectively removes the protective cover from the slope, but it does not change the value of the slope angle. This process of block sliding takes place on differing scales as may be seen from the way in which the main scarp of this initial and largest landslides is itself cut by the scarps of several smaller landslides. Some of these smaller landslides are similar in character to, but younger than the largest scarp. In other words, some of these smaller landslides have the same character as the largest slide.
In addition to these slab-like landslides, the lower part of the slope displays slumps, landslides created by failure along a spoon-shaped slip surface. These slumps typically form in material from which all vegetative cover has been removed. The most recent of these have all formed in the summer and fall of 1993. These slumps apparently are triggered by undercutting at the shoreline, especially if the slope above has been denuded of vegetation. The formation of these slumps creates regions where the slope is very steep, commonly vertical. These vertical faces are inherently unstable, and failure occurs here through topple and fall as illustrated at stop 2. It appears that once this stage has been set in motion, a threshold has been crossed so that slope steepening becomes the rule.

STOP 2. Wang site SE-09-88
Access from Bayview YMCA Parking lot. From Bayview YMCA walk down road to burned-out building and through it to the ORV trail marked by orange paint blazes. Continue to Stop 2 at the shoreline. (Alternative access from Smith Road at Empire Boulevard. Smith Road terminates at the east shore of Irondequoit Bay adjacent to a quonset hut owned by the Rochester Canoe Club.)
Discussion topics: ( 1) Lake Iroquois sediments. (2) Present-day processes, especially topple and slump observable in real time. (3) Inception of bluff development in the 1960s.
This site displays 3 bluffs (very steep unvegetated slopes), each of which is vertical in its upper part. The highest bluff rises 26 m (85ft) above water level. The vertical upper face of these bluffs is created in a cohesive clay unit. Earth slump and earth flow of the non-cohesive materials that underlie this clay unit set the stage for the opening of vertical joints in the clay unit. Blocks of the clay unit as large as 2 m on a side then fall from this free face, sometimes remaining intact and sometimes breaking into numerous small blocks.
Below the vertical face are fans of material that has fallen from above and then accumulated at the base. Some vegetation has taken root in this material. During the summer and fall of 1993 and the late spring of 1994, these aprons were being eroded by wave action, and this erosion and undercutting of the base was triggering earth slumps 2.5 to 3.6 m (8 to 12 ft) high at the base of the bluffs. Earth flow is also common in the fans. Most of the steps in the process can be observed in real time whenever waves and boat wakes break along the base of this bluff.
These 3 bluffs first appear in the 1961 aerial photographs; they cannot be recognized in older photographs. They are interpreted as the end product of landslide processes that first operated on steep but vegetated slopes. Remnants of these slopes are still present. Complete removal of the original soil blanket and the vegetation rooted in that blanket set the stage for the operation of slump processes. Undercutting by wave action during periods of high lake level (as in 1973 and 1993) removed the protective aprons, cut a shelf under the vertical bluff, and set the stage for earth topple noted above.

STOP 3. Wang site NE-05-88
Walk north along trail to water tower and then down the west-facing slope west of the water tank at the Webster Water pumping facility.
Discussion topics: (1) Use of multiple scarps in establishing landslide history (oldest and highest scarp dates from 1930 or earlier). (2) Role of high water level and wave activity in setting the stage for slump activity. (3) Probability of future landslide activity. (4) Nature of Lake Iroquois sediments.
This slope displays at least 6 different landslide scarps ranging in age from 1930 (or older) to 1994. The oldest scarp (top at 33 m -110 ft) above water level outlines a landslide area (probable earth block slide) visible on the 1930 aerial photograph. The entire slope within this oldest scarp displays none of the large trees that are uniformly present in the area outside of the scarp line. There were few large trees on this slope even in 1930. The upper part of this oldest landslide is covered by grass, bushes, and by a few trees less than 15 cm (6 in) in diameter.
All of the other scarps lying within the slope area bounded by the oldest scarp are displayed at lower elevations ranging from 8 m to 33 m (27 ft to 108 ft) above water level. Each scarp bounds a separate landslide, some of which are earth slumps. The youngest of these landslides, re-activated in 1993 when lake level was at a 20-year high, illustrates the conversion of a steeply sloping landslide site to an earth slump and vertical bluff.
The earth slump displayed in the lowermost 15 m (50 ft) of this slope began to form prior to 1978. It exposes an excellent sample of the type of section generally seen north of the Route 104 bridge. A clay layer at the base of the slope is overlain. by at least 6 m (20 ft) of sand and silt displaying the climbing ripples characteristic of all northern sections. The upper edge of the scarp of this slump was at 15 m (50 ft) above lake level in May 1994. The upper 2 m of section display clay and silt layers with prominent pillow structures.
The inferred history of this site is as follows: (1-pre 1930) Undercutting at the base; large-scale earth-block sliding of blocks made up of the soil horizons. There were few trees left on this slope after this event. (2) Removal of tree cover, followed by episodes of high lake level led to the inception of the processes active in 1993-1994. (3) Undercutting of the base of the slope by wave action during periods of high water level. Major periods of high water level occurred in 1952, 1973, and 1993. (4) Failure by earth slumping, flow, and topple. These three types of landslide activity occur in conjunction with one another as illustrated by relationships expected to be visible in October 1994.

STOP 4. Genesee River at Dutch Corners Road.
Discussion topics: (1) Rates of migration of Christiano meander (this stop) and Route 20A meander (compare figures 7 and 8), (2) Meander migration process at times of high discharge, (3) Possible role of controlled discharge controlled by the Mount Morris dam.

STOP 5. Route 20A at Boyd Parker Park.
This bridge was destroyed by subsidence 12 March 1994. It is not known at this time (June 1994) if this site will be accessible.
Discussion topics: (1) The sequence of subsidence events (see figure 8), (2) The relation between subsidence and the mine workings, (3) Hydrologic questions, (4) Future prospects for subsidence and hydrologic impacts.

B2: ORDOVICIAN AND SILURIAN STRATA IN THE GENESEE VALLEY AREA SEQUENCES, CYCLES AND FACIES
WILLIAM M. GOODMAN
The Sear-Brown Group
85 Metro Park
STEVEN T. LODUCA
Department of Geography & Geology
Eastern Michigan University
Ypsilanti, Michigan 48197
DAVID F. LEHMANN
Huntingdon Engineering and Environmental
535 Summit Point Drive
Henrietta, New York 14467
Upper Ordovician and Silurian strata in New York State are well-known from their spectacular exposures in the Niagara and Genesee River Gorges. Because of the excellent exposures in western New York, the descriptive stratigraphy of these units is well-refined, and the interval has recently been used as a test case for models of eustatic and tectonic stratigraphic dynamics. Important modern works concerning the litho-and biostratigraphy of these strata include Gillette (1947), Fisher (1953, 1960, 1966), Kilgour (1963), Rexroad and Rickard (1965), Zenger (1965, 1971), Rickard (1969, 1975), Martini (1971), Brett (1983), Duke (1991) and Loduca and Brett (1991 ). Allostratigraphic analyses have been performed by Duke and Fawcett (1987), Brett et al. (1990a, b; 1991) and Goodman and Brett (1994).
The Upper Ordovician and Silurian strata of the Genesee Valley and surrounding areas were deposited near the northern reaches of a dynamic and rapidly evolving Appalachian foreland basin. The striking patterns of unconformity and lateral basin axis shift are striking given that the Late Ordovician and Silurian Periods are generally considered to be times of tectonic quiescence between the Taconic (late Middle Ordovician) and Acadian (Middle to Late Devonian) Orogenies. Foreland basin flexure produced asymmetric marginal unconformities, but the differential subsidence did not obscure relative sea-level trends in litho-and biofacies that correlate with patterns in other basins. Thus, the stratigraphic interval exposed in the Genesee Gorge is an excellent field laboratory for the interaction between tectonic foreland basin flexure and eustatic sea-level changes.
During the Late Ordovician and Silurian, the northern Appalachian Basin was situated within a subtropical climatic belt, probably at about 20 to 25 degrees south latitude (Van der Voo, 1988, Witzke, 1990). Climates apparently oscillated from relatively arid during the Late Ordovician to humid during the Early Silurian and back to very arid during the Late Silurian. During the Late Ordovician and Early Silurian, the bulk of the basin fill in western New York represents marginal marine to nonmarine settings. Siliciclastic sediment that infilled the basin appears to have been shed from rejuvenated Taconic source areas primarily located to the east and southeast. Open marine facies that are time-correlative to the Queenston Shale and Medina Group are situated northwest of the Niagara region.
A low forebulge, Algonquin was intermittently uplifted along to northwestern rim of the basin (Figure 1).
Subtidal ramp carbonates are preserved in the lower Clinton Group between Niagara and Wayne Counties, New York. The onset of clean carbonate deposition stratigraphically above a low angle, regional unconformity at the top of the Medina Group suggests structural uplifting of the Algonquin Arch during lower Clinton time. Unfortunately, a late Llandoverian unconformity that divides the Clinton Group into two units removed a significant portion of the lower Clinton stratigraphic record in western New York. Consequently, paleogeographic reconstructions can only be indirectly inferred from biofacies and textural trends in the truncated carbonates and siliciclastic facies belts situated farther east.
During the Late Silurian (Wenlockian and Ludlovian Epochs), upper Clinton and Lockport carbonates accumulated on the western basin ramp. Except for the Wenlockian eustatic sea-level highstand during which the fossiliferous Rochester Shale accumulated over significant portions of the basin, persistent siliciclastic sedimentation was restricted to the eastern ramp and basin center. Shales and mudstones commonly occupy the central, offshore facies belt. The eastern strandline facies belt is dominated by sandstone and conglomerate.
Late in the Silurian (Pridolian Epoch), circulation within the basin became restricted in response to increased aridity and fringing reefs of the Guelph Formation (Rickard, 1969). Increased siliciclastic sedimentation associated with the formation of the Bloomsburg-Vernon deltaic complex may signal rejuvenation of the eastern basin flank and cannibalization of Upper Ordovician and Lower Silurian strata during the Salinic Disturbance. Following accumulation of deltaic red beds across western New York, a thick sequence of peritidal carbonates, mudstones and evaporites (Salina Group) accumulated in western New York and surrounding areas. Resumption of more normal shallow marine conditions is recorded in the Cobleskill biohermal dolostone which is the youngest pre-Helderberg Silurian unit preserved west of Cayuga County.
In this paper, details of upper Ordovician and Silurian stratigraphy are provided in a regional context so that a framework may be established for the Rochester area facies. Where interpretations of allostratigraphy have been developed, depositional sequences and smaller, component cycles are discussed. This presentation proceeds in ascending stratigraphic order.

B2: ORDOVICIAN AND SILURIAN STRATA IN THE GENESEE VALLEY AREA SEQUENCES, CYCLES AND FACIES

Ascending Pinnacle Hills moraine
Ascending Pinnacle Hills moraine to crest at Highland Avenue; Mt. Hope Cemetery on left is built on eggs-in-a-basket kame sand and gravels; this classic cemetery displays beautiful small-scale kettles and kames. Modern Genesee Gorge was initiated when Lake Scottsville waters poured over low spot in the Pinnacle Hills moraine just west of the cemetery at University site.

Descending Pinnacle Hills moraine

Rochester's oldest building
Site of Rochester's oldest building (1 Mt. Hope), on left made of local Medina sandstone

Access to the Middle Falls of the Genesee.
Brewer Street to left at St. Matthews Church with red tiled roof; this small road provides access to the Middle Falls of the Genesee.

STOP 1A-GENESEE RIVER GORGE AT LOWER FALLS ON RG&E ACCESS ROAD
The best section of the Upper Ordovician and Lower Silurian rock in the Genesee Gorge is exposed along the access road to the Rochester Gas and Electric Company (RG & E) Power Plant #5 on the east side of the Genesee Gorge (Liebe and Grasso, 1988). The road is open to pedestrians as a fisherman's access, and starts at a gate just south of Seth Green Drive, opposite the intersection of St. Paul Street and Norton Street. Stratigraphically lowest outcrops on the roadcut are beneath and just south of the newly reconstructed Driving Park (Avenue E) Bridge; roadcuts extend for about 0.7 km northeast of the bridge along the access road.
The easily accessible portion of the succession ranges from the Queenston Shale upward to Reynales carbonates. These units will be described successively in the following sections.
Queenston Shale
The lowest unit exposed in the Rochester area is brick red mudstone and fine-grained sandstone of the Late Ordovician (Ashgillian) Queenston Shale. The Queenston Shale is believed to be separated by an unconformity from the overlying Silurian beds, although the magnitude of this unconformity is difficult to determine because of the unfossiliferous nature of rocks above and below it.
Only the upper 15 to 20 meters of Queenston Shale is exposed in the Genesee Gorge below the Lower Falls. The formation is estimated to be over 300 m (1 000 ft) thick in the Rochester area. Sandstones are typically lenticular and exhibit small-scale trough cross stratification, asymmetrical ripples and desiccation cracks (Duke, 1987). The Queenston Shale exposed in New York State generally lacks body fossils but contains varied horizontal and vertical burrows. One fine-grained sandstone displaying Skolithos occurs immediately below the contact with the overlying Medina Group. Paleoflow directions determined from crossbedding indicate a dominant north-northwest current orientation.
Broadly, the Queenston reflects post-orogenic molasse derived from the Taconic source terrain which existed some 300 km to the southeast of Rochester during late Ordovician time. The Queenston culminates a shallowing-upward (pro-gradational) sequence and records over-filling of the Appalachian basin with siliciclastic debris. The formation is often regarded as a tectonic fan delta, the so-called Queenston Deltaic Complex.
Medina Group
The Medina Group exposed in the Genesee River Gorge is composed of 17 m (50 ft) of red-and white-mottled sandstone with a few beds of red mudstone and siltstone. The sequence has recently been revised and divided into five units: the Devil's Hole, Grimsby, and Thorold sandstones, Cambria Shale, and Kodak Sandstone.
The lowest three meters of reddish coarse sandstone represent a distinct interval thought to be correlative with the Devil's Hole phosphatic sandstones in western New York and Ontario (Duke 1987; pers. comm. 1988). This lowest Medina interval weathers as a massive ledge of planar laminated to trough cross-stratified, subarkosic, medium-space to coarse-grained sandstone and can be informally divided into two portions. The lowest bed displays a sharp to slightly undulating contact on the uppermost fine-grained sandstone beds of the Queenston Formation. There is some evidence for erosion on this surface which represents a widespread Ordovician-Silurian disconformity of considerable magnitude (Cherokee discontinuity of Dennison and Head, 1975). The presence of iron and phosphatic ooids and crinoids, together with coarse quartz granules suggest that this basal unit in part represents a transgressive lag deposit (Duke, 1987). These sediments have probably been reworked in a shallow marine bar-tidal channel complex. Higher parts of the Medina, assigned to the Grimsby Sandstone,include three small scale bed-thickening and coarsening-upward successions. The predominant lithologies are red and white mottled, cross-laminated to planar bedded sandstone and maroon shale. The tops of the cycles are sharply overlain by channel-filling sandstone bodies that display lateral accretion surfaces. The erosive bases of these channels have removed much of the underlying coarsening upward strata in underlying cycles. Upper portions of the sandstone bodies are strongly bioturbated.
A highly distinctive interval of massive pink and white mottled sandstone overlies the Grimsby with a sharp, erosive contact. The basal massive ledge, about 4m below the white Kodak Sandstone displays spectacular Arthrophycus and Daedalus trace fossils, which probably represent mining traces (fodinichinia) of large worm-like organisms. The latter consists of complexly swirled spreiten structures that protrude downward for up to 70 cm. This interval, formerly referred to as Daedalus bed, has recently been correlated with the Thorold Sandstone of western New York and Ontario (Brett et al, 1990a,b; Duke, 1991 ); in contrast, most previous workers (Gillette, 1947; Fisher, 1953, 1960) correlated the Thorold with the higher Kodak Sandstone of Rochester.
The presence of larger-scale, coarsening-upward sequences capped by fining-upward channel sandstones suggests aggradational tidal flat and channel settings of the upper Grimsby and Thorold sediments. The absence of body fossils in the sandstone may indicate the presence of brackish water in which the trace makers of Daedalus and Arthrophycus apparently flourished; recent discoveries suggest that these two traces represent different behavioral patterns of a single species of infaunal animal.
The maroon siltstones and shales of the Cambria Shale, which conformably overlie the "Daedalus bed", were apparently deposited in restricted subtidal settings. Ostracodes are present in drill cores as far east as Webster, New York and a trilobite resting trace, Rusophycus, has been noted in Cambria strata of the Rochester area.
The Kodak Sandstone forms a distinctive 1.5 m light gray band of heavily bioturbated friable arenite. This unit displays a sharp but probably conformable contact with the underlying Cambria coarsening upward cycle. Iron in the Kodak has been reduced or leached altered due to percolation of reducing waters from the overlying Maplewood muds. Hence, the Kodak is (pale) greenish grey color, as is any unit which directly underlies the Maplewood (Duke and Fawcett, 1987; Duke, 1991 ). This diagenetic "bleaching" has resulted in a light zone at the top of the Medina at all localities in western New York, despite the presence of various units beneath a regionally angular unconformity; as a result the Kodak was previously miss-correlated with the Thorold in the west. The Kodak Sandstone, which forms the cap rock of the Lower Falls on the Genesee River, is poorly dated because of an absence of zonally significant fossils, but it is generally regarded as of early Llandoverian age (Maxwell and Over, 1994).
Clinton Group
The Clinton Group at the Genesee River Gorge consists of a heterogeneous assemblage of shale and carbonates and one thin hematitic bed, totaling about 55 m (170 ft) in thickness. These rocks span middle Llandoverian to early Wenlockian age. The Clinton contains a major unconformity, recently described in detail by Un and Brett (1988) and thus can be informally subdivided into upper and lower Clinton strata, following the earlier use age of Gillette (1947).
The Maplewood Shale, lowest of the Clinton units, consists of 6 m (18 ft) of soft greenish-grey clay shales. Despite its prominence in the Genesee Gorge, the unit pinches out at Webster only 10 km northeast of Rochester. Macrofossils are very rare in the Maplewood Shale, although recently S.J. Ciurca (pers. comm.) has obtained lingulid brachiopods, nautiloids, eurypterid fragments, and complete specimens of a new species of crinoid from it. The Maplewood is noted for its diverse and well preserved microflora acritarchs and chitinozoans (Fisher, 1960; Miller and Eames, 1982). The Maplewood muds were probably deposited in shallow, but stagnant, low energy nearshore settings (lagoonal).
Maplewood shales are bounded by phosphatic pebble beds at the base and top. A zone, up to 10 cm thick, at the base of the unit carries large clasts of phosphatized sandy carbonate and black fossil steinkerns of fluoroapatite (Boger and Sutphin, 1984; Paxson, 1985). This zone, the Densmore Creek phosphate bed, records a significant disconformity that can be traced westward into Niagara County, where it erosionally truncates the underlying Kodak Sandstone. This establishes the basal sequence boundary of Sequence II. To the east of Rochester this pebble bed is more hematitic and grades in the Webster bed of the Furnaceville Formation (LoDuca and Brett, 1994). The unit apparently records an interval of sediment starvation and erosion associated with the initial Clinton sea level rise. The upper contact of the Maplewood is also marked by a phosphatic bed at the base of the overlying Brewer Dock Member of the Reynales Formation.
The Reynales Formation is a carbonate-rich interval well exposed along the upper end of the RG&E access road; the age of this formation is debatable, but it probably ranges around Middle Llandoverian and contains the boundary between the D. kentuckyensis and staurognathoides conodont zones (Maxwell and Over, 1994). The formation is subdivided into three members (Paxson, 1985). A basal 0.6 m (20 in) thick Brewer Dock Member consists of nodular silty limestones with abundant phosphate pellets and interbedded green shales. This unit is rich in fossil bryozoans, brachiopods, and crinoid ossicles. The Brewer Dock is overlain by a distinctive, 30 cm-thick hematite band which, incorrectly, has been called Furnaceville. The hematite bed, referred to as the Seneca Park Hematite by LoDuca and Brett (1994), overlies a prominent zone of ball-and-pillow deformation. It is dull-red fossil ore, comprising hematite-replaced Helopora and other bryozoans, crinoid columnals, and rare ooids. The hematite bed displays cross-stratification with a north-westward paleo direction and a rippled top.
The upper Reynales (or Wallington Member) is a 5-6 m (16-18 ft) thick interval of thin to medium bedded, medium grey dolomitic limestone with greenish grey silty shale interbeds and partings particularly near the base. Most of the carbonate is laminated pelletal grainstone. Several beds in the lower portion of the unit contain bluish-grey chert nodules. Fossils, include Eocoelia brachiopods and complete specimens of the unusual crinoid Stipatocrinus (Eckert and Brett, 1987). Several beds, most notably a one meter thick ledge-former near the top of the formation, contain large specimens of the brachiopod Pentamerus oblongus, indicative of shallow, agitated shoal settings.

STOP 1B. LOWER FALLS, GENESEE RIVER
This overlook provides a panorama of the Lower Falls of the Rochester Gorge. The Lower Falls, with a drop of 30 m (97 ft), is capped by resistant sandstones of the Upper Grimsby and Kodak Formations.
The stratigraphic units examined previously (Stop 1 A; Queenston Shale to Reynales Limestone) are clearly visible near the base of the gorge beneath and immediately south of the Driving Park Bridge. Higher units of the Clinton Group can also be viewed from this vantage point although their limited accessibility precludes close examination during this trip.
The Reynales carbonates are observable immediately opposite this point near the base of the large water surge tank of the Rochester Gas and Electric Company. They are overlain by an interval of shales which actually constitute two distinct units. The lower 4.4 m (13 ft) of greenish to purple Lower Sodus Shale is unconformably overlain by 2 m (6 ft) of black to greenish-grey, graptolite-bearing Williamson Shale. The contact of these formations is cryptic but actually represents a significant, regional, angular unconformity that bevels successively older units in a westward direction (Lin and Brett, 1988). This erosional surface, which may reflect the eastward migration of a forebulge, is onlapped by a widespread dark shale of the latest Llandoverian Williamson Formation. The Williamson Shale is followed by thin-bedded dolomitic carbonates and grey shales of the Rockway Formation. The overlying Irondequoit Formation is thicker-bedded and contains small bryozoan-algal bioherms up to about 2 m in height. These can be seen to deform strata in the cliff near the deck level of the Driving Park Bridge. They were initiated on a single horizon of crinoidal packstone near the base of the Irondequoit Limestone. In turn, the Irondequoit Limestone is overlain here by about 3 m of brownish-grey, fossiliferous Rochester Shale, which is bevelled and overlain by glacial deposits.

STOP 1C. HIGH (UPPER) FALLS PARK, GENESEE RIVER
This park provides a view of the 25m (80 ft) High Falls, formerly a major source of water power for industry. Rochester developed as a grain milling center in the mid 1800's largely as a result of its location on the Erie Canal and the presence of this source of power (seeGrasso and Leibe article in this guidebook). Nearly vertical cliffs in the Genesee River Gorge below the High Falls display almost complete section of the Rochester Shale. This may be the oldest type locality in North America, the Rochester Shale having been named by James Hall in 1839. The Rochester Shale, here about 30 m (98 ft) thick, contains grey, calcareous shale with numerous thin calcisiltites (Brett, 1983a). The Rochester Shale is moderately to sparsely fossiliferous with an abundance of brachiopods and the trilobite Dalmanites. However, it is largely inaccessible at the type section. The Rochester appears to record a slight shallowing of relative sea level, with an increase in the number and thickness of dolomitic carbonate interbeds toward the top as it passes up into the predominantly carbonate DeCew and Lockport Formations. The upper unit of the Rochester Shale, comprising approximately a third of the diff at this section, is the Gates Member. The Gates, DeCew, and Lockport units will be examined in greater detail at Penfield quarry (Stop 3). Rochester and DeCew strata represent shallow subtidal, muddy marine deposits, as indicated by the abundance of fossils and lack of tidal features.

Broad St; bridge on old aqueduct

Penfield and Eramosa fms.
Former "Can of Worms" area, minor low cuts in upper Penfield and Eramosa formations of Lockport Group formerly biostromes were exposed near top of Penfield.

There are low cuts in DeCew dolostone along exit.

STOP 2. PALMER'S GLEN (TRYON PARK)
Walk into the field into the right of the highway and then straight, paralleling the highway, down a bank, to ramp road of sewage treatment plant leading down to the level of small creek.
This unnamed creek, informally referred to as Palmer's Glen, also serves as an overflow stream for the storm sewer system. The water in the creek is contaminated to some degree and should be dealt with cautiously.
Lowest exposures along the banks of this creek are at the lower part of the Sodus Formation. This interval is slightly above the upper beds viewed at the Genesee gorge along Seth Green Drive. The shales here range from greenish gray to light purplish gray in color. The purple colored shales appear to cap small shallowing cycles within the Sodus. These cycles commence with thin shelly and, in some cases, phosphatic beds and pass upward into greenish gray shales and these latter gray upward to purplish hued shales. Both green and purple shales contain a shallow marine fauna of the classic Eocoelia biofacies of (Boucot, 1975) Bedding plane assemblages are dominated by Eocoelia cf. E. hemispherica. These are mixed with small bivalves (pteriniids), rare Leptaena, small tabulate corals, Tentaculites, and abundant ostracods of the Zygobolba decora zone. At this locality thicker coquina beds of sandy limestone rich in Eocoelia also occur near the top of the Sodus.
The Sodus is capped by a major erosion surface, probably the largest unconformity within the Silurian. However, the unconformity is relatively cryptic at this locality, and is overlain by hard black shale of the Williamson Formation. The contact here is marked by a thin yellowish clay, which could be a bentonite. The basal Second Creek bed of the Williamson Shale is a thin phosphatic, skeletal rich sandstone generally less than one centimeter in thickness. Higher beds consist of an alternation of decimeter-scale hard dark gray shale and soft greenish gray shale beds. The black shales contain laminae of fine quartz sand, some of which possess small scale asymmetrical ripples on their tops. The black sandy shales also display well preserved graptolites of the Monograptus clintonensus-Retiolites venosus assemblage. These graptolites, together with abundant conodonts obtained from basal lags within the Williamson Shale, indicate a latest Llandovery (or late Telychian) age for these shales. The Williamson here is approximately four meters in thickness. It is overlain at a minor disconformity by the dolomitic limestones and greenish gray shales of the Rockway Formation. A thin bed at the base of the Rockway contains quartz granules and small pebbles as well as black phosphatic nodules, but these are highly scattered and the bed is difficult to observe. In turn, the Rockway is approximately 2.8 m-thick and is overlain by 3.2 m. of dolomitic crinoidal wacke-to packstones of the Irondequoit Formation. These rocks occur high in the bank at this section, and can be best viewed by walking downstream approximately 100ft to the fork of Browncroft Creek, and walking upstream (south) into the Browncroft fork. Here the Rockway, Irondequoit and basal Rochester Shale can be viewed at a small waterfall section.

Small stream on right exposes upper portion of Rochester Shale

Ascending hill out of Irondequoit Valley
This is the old River Valley of the preglacial Genesee River, now occupied by underfit Irondequoit Creek.

STOP 3. DOLOMITE PRODUCTS QUARRY, PENFIELD
This large, active dolomite quarry, about 30 m (100 ft) deep, exposes a nearly complete section of the Lockport Group and its contact with the underlying Clinton Group (Grasso and Friedman, 1989; Zenger, 1965). Crushed stone quarried at this location is used primarily for road-paving material. The quarry is famous among amateur mineral collectors as a source for euhedral crystals of saddle dolomite, calcite, sphalerite, galena, pyrite, celestite, selenite, and especially, clear bluish fluorite which occur in 20 to 50 cm. diameter vugs within the dolostone at several horizons. The source and timing of the mineralization is enigmatic but it occurred at temperatures of approximately 150°C. Mineralization occurred selectively within cavities produced during dolomitization, many of which represent former coral and stromatoporoid heads. Dolomitization in the Lockport Group is evidently of replacement type and has resulted in strong recrystallization and obliteration of much of the primary carbonate fabric. Dolomitization may have been produced by seepage refluxion of brines during deposition of the overlying Salina Group or may be of deep burial origin.
The Penfield Quarry was studied in detail by Zenger (1965), who designated this exposure as the type section of his Penfield Member, here comprising 19.2 m (63 ft) of sandy dolostone and dolomitic sandstone. Zenger also identified the upper 5.2 m (17 ft) of the section here as basal "Oak Orchard Member," which is now referred to as the Eramosa Formation. Recent deepening of the quarry and detailed regional correlation permit a reevaluation of this stratigraphy (Brett, et al., in prep.). The Gates Member of the upper Rochester Shale is the lowest unit exposed in the quarry. It can be observed in a sump pit near the western edge of the quarry. The Gates contains dark grey, sparsely fossiliferous, bioturbated, silty, dolomitic mudstone and argillaceous dolostone. Planar and irregular (hummocky?) cross-stratification common in silty layers; many bedding planes contain the dendritic feeding trace Chondrites and oscillation/interference ripple marks aligned roughly NE-SW. Lingulid and rhynchonellid brachiopods and crinoid ossicles are present, a spectacular occurrence of over 1000 complete crinoids (Dimerocrinites) was discovered in this portion of the quarry.
The Gates Member is overlain at a sharp contact by about 3 m (15') of thick-bedded to massive DeCew Dolostone. The lowest meter is a blocky bed of sandy, pale gray, buff-weathering dolostone with soft sediment deformation and hummocky cross-stratification that is prominently displayed in the main lower floor of the quarry. The hummocks are ellipsoidal, average approximately 1 m in length along their long axes, and are spaced about 0.5-1.0 m apart.
The basal DeCew was probably the lowest unit exposed when Zenger measured the quarry. Subsequent cutting of the sump pit revealed that the quarry floor was very close to the base of the DeCew, (whereas Zenger had apparently considered it the top of that formation). This bed is overlain by about 5 m (15 ft) of dolomitic sandstone and arenaceous dolostone with two prominent partings which display rusty staining due to ground water seepage. The DeCew is sparsely fossiliferous except for scattered stringers of crinoid columnals and occasional orbicerloid brachiopods, but sandy beds contain vertical Skolithos-like burrows. The Gates-DeCew interval is interpreted as mixed siliciclastic and allodapic carbonate sands and silts which were rapidly deposited basin-ward of shallow, winnowed platforms developed north (?) of this area. Gates-DeCew sediments accumulated in shallow subtidal areas below fair-weather wave base but subjected to frequent storm wave disturbance. Most of the higher quarry wall is composed of brownish grey to medium grey, medium-to thick-bedded, sandy dolostone which displays planar and bidirectional cross-stratification. Layers and lenses of crinoidal grainstone occur in the lower 5 m which terminate at the top of the lower level of the quarry. The meter-thick bed just below the second bench of the quarry (approximately 12.5 m) is highly crinoidal and contains intraclasts as well as rare rugosan and favositid corals. It is overlain by a 9 m (28.5 ft) interval of medium and even-bedded, sandy dolostone, with thin shaley partings, that appears to correlate with the Goat Island and Eramosa formations of the Lockport Group.
The entire 15 m interval, corresponding to the members of the Gasport, Goat Island, and Eramosa formations, is enriched in quartz sand in the Rochester area, and the name Penfield Formation is perhaps useful in emphasizing this facies distinction. However, it should be noted that members, and even certain marker beds, in the Gasport interval can be traced across the facies change. Crowley (1973, unpubl.) emphasized the locally sandy nature of the Penfield and interpreted the unit as representing a shallow water sandy shoal or "Penfield island"; but the persistence of sedimentary cycles and elements of the typical Gasport marine fauna into the Penfield area indicates an environment similar to that of the typical Gasport facies. Crinoidal grainstones of the Gasport and sandy crinoidal dolostones of the lower Penfield represent similar environments, i.e., a shallow wave-winnowed and perhaps tidally-influenced (bimodal cross stratification) shelf with local shoals or bars, close to fair weather wave base. The increased sand content of this facies in the Penfield area appears to indicate a local source of siliciclastics north of this region. Upper units are thinner-bedded and more argillaceous than the Gasport equivalents and record a transition to somewhat lower energy, probably deeper water environments similar to those in which the Gates-DeCew interval sediments accumulated.
The highest beds exposed in the Penfield Quarry consist of massive, highly fossiliferous and vuggy dolostones that were assigned to the lower 5.5 m (17 ft) portion of the "Oak Orchard Member" by Zenger (1965); recent study demonstrates that the term Oak Orchard is invalid, and we assign these beds to the Eramosa Formation Prominent, 0.5 m thick, light grey-weathering, dolostone beds occur about 2 and 3 m below the top of the quarry. Dark biostromal beds on either side of these horizons are rich in poorly preserved, and typically mineralized tabulate corals (Favosites, Cladopora), and small domal stromatoporoids. These beds contain numerous large vugs which are lined with nodular anhydrite, scalenohedral calcite, pink saddle dolomite, celestite, sphalerite, rare fluorite and sulfides; these vugs are the principal source of the Penfield minerals. Although the vuggy beds are inaccessible in the vertical quarry walls, they can be examined readily in large fallen blocks piled on the higher bench in the quarry.
The upper Lockport strata at Penfield (>5 m) are distinctly less sandy than the lower beds and more highly fossiliferous. The Eramose interval records a general decrease in the input of siliciclastic sediments and the development of coral-stromatoporoid biostomes and associated carbonate sediments in shallow, but relatively quiet water environments.

Westernmost known exposure of Wolcott Limestone
A small outcrop in ditch is the westernmost known exposure of Wolcott Limestone; the unit is truncated between this locality and Rochester.

STOP 4. (optional) OLD FRUITLAND ORE PITS PARK
Park in lot near building and walk to the right (north) past end of pond and then left (west) along the north side of the pond onto dump piles of rock dug from the pond.
The ponds in this park represent old pits dug in the Furnaceville hematite or iron ore bed for the production of red paint oxide (Gillette, 1947). Although in-place rock is no longer accessible within the flooded pits, dump piles provide an overview of the lithology of the Reynales Formation. Most slabs consist of dolomitic limestone with minor bluish gray chert nodules. Molds of pentamerid brachiopods are common on certain slabs. Pentalobate columns of the newly described inadunata crinoid Haptocrinus are relatively abundant. While most of the hematitic band was removed for the paint ore production, occasional blocks and slabs show the highly fossiliferous, oolitic hematite.

Furnace Road (named for old blast furnaces for iron production from Furnaceville iron ore).

Williamson Shale type section
Cross Salmon Creek, type section of the mid Silurian Williamson Shale is slightly upstream (south) of road.

Small exposure of yellowish weathering Rockway Shale is in ditch.

Very minor low outcrops of Rochester Shale in ditch to south.

View of large wave modified drumlin on right (south).

Rochester Shale below road.

Glenmark Shale with distinctive fauna
Note ditch to north (left) near Wallington town line; yellowish clay is weathered Glenmark Shale (formerly considered as upper part of Rochester Shale). This small exposure has yielded very abundant brachiopods, especially Nucleospira pisiformis, and small Enterolasma (rugose corals) Stegerhynchus neglectum. The Glenmark horizon with its distinctive fauna can be correlated from this small outcrop southward into the central Appalachians of Pennsylvania, Maryland, and West Virginia.

STOP 5A. SECOND CREEK AT ALTON
Park opposite southern fence line segarating planted field to south from sheep pasture on left (west) side of Shaker Road. This is the former Shaker Tract, or Alasa farms: white barns to the north now house the Lake Plains Wildlife Rehabilitation Center
Follow along edge of fence back to woods bordering east side of Second Creek: enter woods and turn right following near tog of bank for about 0.1 mile to where an old logging road descends to creek level: go downstream {north) for one major bend and walk across floodplain and creek to bank on west side.
This creek bank exposes a small but excellent section of the Clinton strata. Lowest beds exposed are in the Wolcott Furnace Formation, which consists of alternating greenish gray fossiliferous shales and limestones, containing an undescribed stricklandiid brachiopod, together with chaetetid sclerosponges, crinoid ossicles and small Enterolasma rugose corals. These beds also display thin fossiliferous hematitic limestone bands. At the top of this interval is a thin, but distinct bed containing granular black phosphatic material. About 20 cm of overlying greenish gray shale may represent the westernmost occurrence of the Sauquoit Shale, an interval which exceeds 30 m (100 ft) in thickness in east central New York, south of Utica. Here the interval has very nearly been truncated by an erosional surface. This unconformity is marked by a sharp surface and a very distinctive lag conglomeratic bed (the Second Creek phosphatic bed), best developed at this locality. This bed is approximately 1 to 2 cm in thickness, but in places, it contains clasts of dolomitic limestone, evidently derived from nearby exposures of the Wolcott or other lower Clinton carbonates. The clasts rarely exceed a cm in thickness, but may be up to 10 cm across. In places, these clasts are edgewise and may jut upward into the overlying Williamson Shale a few centimeters. The erosional clasts are packed in a matrix of dark gray, very pyrite-and phosphate-rich crinoidal grainstone. Pebbles of black phosphate and quartz up to 1 centimeter in diameter are present within the matrix. The lower surface of the bed is typically sharp and slightly irregular. Its upper contact is sharply overlain by black or very dark gray Williamson Shale and typically displays an abundance of the brachiopods Eoplectodonta and Atrypa. Current aligned specimens of the graptolite Monograptus clintonensus occur on the contact in some places. The unconformity here is the same one examined at Palmers Glen near Rochester (STOP 2). However, here the Williamson Second Creek phosphate bed unconformably overlies a remnant of the Sauquoit Formation, whereas at Rochester, the Williamson rests on the lower portion of the Sodus, some 10 m lower in the section. Hence, the unconformity is regionally angular and has truncated successively older Clinton strata to the west.
The overlying Williamson Shale includes alternating relatively hard, very dark gray to black graptolitic shale and soft greenish gray claystones. As at the Palmers Glen exposure (STOP 2), graptolites are generally confined to the dark gray layers and may occur on laminae of quartz sand or very coarse silt. Greenish gray layers are generally barren of fossils but may contain bedding plane assemblages of frilly Atrypa and Eoplectodonta. We will walk upstream along the bank of Second Creek to outcrops of the Rockway Dolostone and shale and the Irondequoit Limestone. The Rockway, well displayed in slabs recently ripped up during flooding from the creek floor, is fossiliferous, somewhat greenish gray silty mudstone, which weathers to a yellowish color. It contains an abundance of brachiopods, particularly Clorinda, (considered a classic deeper water, benthic assemblage 4 to 5 indicator), Leptaena, Atrypa, and others. The shales also contain scattered specimens of the small rugose coral Enterolasma and this locality has yielded specimens of the probable green alga Ischadites. Thin, muddy, micritic limestones interbedded with the shales contain scattered crinoid-bryozoan debris, including calyces of the tiny inadunata crinoid Pisocrinus. The contact with the overlying Irondequoit Limestone at this locality appears conformable, but relatively sharp. The Irondequoit consists of approximately 3 m of crinoid-and brachiopod-rich wacke-and packstone limestone. Small bioherms of bryozoans and possible algal bound micrite are also present at several levels in the creek bed and minor waterfalls here. The Irondequoit is interpreted as a relatively major sea level low stand or shallowing event that separates the maximally transgressive Williamson and Rockway deposits from the overlying deeper water Rochester Shale. The small patch reefs appear to have grown upward during times of relative deepening as the Irondequoit passed upward into mudstones of the Rochester Formation.
If time permits, we may walk further upstream to sample from the richly fossiliferous lower Rochester Shale which contains a diversity of brachiopods, small corals, and trilobites. Most of these fossils, however, are present as disarticulated and somewhat fragmented material.

STOP 5B. (optional) SECOND CREEK AT RED MILL ROAD
If time permits, we may look at the section along Second Creek at Red Mill Road. Immediately downstream from the road bridge are bank outcrops of green to purplish colored Upper Sodus Shale, containing a diverse Eocoelia brachiopod and ostracod rich Zygobolba decora fauna. These beds are sharply overlain by crinoid-and pentamerid-rich grainstones of the Wolcott Formation.

Good view of Sodus Bay to left (north).

STOP 6. UNNAMED TRIBUTARY OF SODUS CREEK
Unnamed tributary of sodus creek immediately east of Norris road and south of US route 104. Pull off to right and park on shoulder of NY 104: walk down into small gully immediately south of the highway at point where an exposed yellowish clay (Rochester Shale) is visible on bank above gully: you can then continue to the south into woods along the unnamed tributary of Sodus Creek.
This small creek provides a relatively complete outcrop of the upper portion of the Rochester Shale. The section begins with the weathered bank parallel to and south of Route 104. This bank yields good specimens of weathered brachiopods, particularly Eospirifer, Rhynchotreta, and Whitfieldella. Upstream, along the main creek, are good exposures of the middle and upper portions of the Rochester Shale. Thick calcisiltite beds occur near the mouth of the stream in some of the lowest exposures. Upstream, a series of low waterfalls or riffles expose highly fossiliferous, bryozoan rich layers corresponding to the upper marker beds of the Lewiston Member (Lewiston E or bryozoan beds in Niagara County, New York), alternating shales and thin biostromal limestones, rich in the small ramose bryozoan Chilotrypa. Associated with these layers are abundant articulated and specimens of the brachiopods Whitfieldella, Rhynchotreta, Eospirifer, Atrypa and rare well preserved specimens of the trilobites Calymene, Bumastus and others.
The change to more sparsely fossiliferous shales above this small falls marks the contact between the Lewiston and Burleigh Hill members. The upper beds, south to the bridge of York Settlement Road, are within the upper part of the Rochester Shale and consist of alternating mudstones, thin shell layers and calcisiltite beds. Some layers particularly near the top are rich in trilobites such as Dalmanites, and brachiopods such as Stegerhynchus, Coolina, Dalejona and occasional small rugose corals (Enterolasma). The change from bryozoan-rich biostromes to more sparsely fossiliferous shales marks a relatively major flooding surface within the Rochester Shale that can be identified throughout much of New York State and Pennsylvania. The upper shaly interval is more monotonous than the lower portion, reflecting highstand conditions. However, in the uppermost 2 to 3 m the shales become increasingly interbedded with dolomitic calcisiltites.
The section is capped by a low waterfalls immediately north of the bridge on York Settlement Road. This falls is capped by a distinctive 40 em-thick massive dolomitic limestone bed, referred to as the basal Glenmark bed. This bed, which contains small favositid and rugose corals, as well as the distinctive brachiopod Nucleospira, marks the approximate position of the DeCew Dolostone of western New York. This bed and the overlying shales, which are rich in distinctive brachiopods, particularly Nucleospira, and Whitfieldella {cf. W. marylandica) represent an important marker interval that is traceable from this area of New York State southward through much of central Pennsylvania Appalachians and into Maryland and West Virginia. This interval, previously unrecognized or treated as simply an upper portion of the Rochester Shale is herein recognized as a distinctive unit referred to as the Glen mark Formation. In nearby Sodus Creek, this 3 · m interval is overlain by thinly bedded micritic limestones and very dark grey, fissile shales, as well as thrombolitic and intraformational conglomeratic horizons marking the base of Sconondoa Formation, the lateral equivalent of the lower part of the Lockport Group of western New York. It represents a distinctive shallowing to nearly peritidal or shallow lagoonal conditions in the late Wenlock or early Ludlow time.

Maplewood Shale was exposed in ditch between two lanes of Rt. 104.

Bay Road
A turn left here would lead to Glen Edith Road and outcrops along road leading down to restaurant by Irondequoit.

East side Irondequoit Bay
Note slumps of soft lake silt; views of bay and bay mouth bar from bridge.

Cross Densmore Creek
Good exposures of Medina and lower Clinton outcrop along the Creek west of the highway to Densmore Road.

B3: THE LEROY BIOHERM REVISITED: EVIDENCE OF A COMPLEX DEVELOPMENTAL HISTORY
THOMAS H. WOLOSZ
Center for Earth & Environmental Sciences
Plattsburgh, N.Y. 12901
DOUGLAS E. PAQUETTE
Safety and Environmental Protection Division
Brookhaven National Laboratory
Building 535A
The LeRoy Bioherm is among the best known rock exposures in New York State, having been designated a National Fossil Coral Reef by the U.S. National Parks Service and having been the subject (at least in part) of three past studies (Crowley and Poore, 1974; Coughlin, 1980; Lindemann, 1988). Despite this the uniqueness of the LeRoy bioherm has generally gone unnoticed. It is the only Edgecliff bioherm known to have a mound building community of the very delicate branching tabulate coral (Ciadopora) and the only known Edgecliff mound with a thickness greater than about 1.2 meters that was not built by phaceloid colonial rugosans (Wolosz, 1992a). Further, the LeRoy Bioherm is the only bioherm in this area with a well developed coral mound facies, while all other Edgecliff bioherms in western New York State are thicket/bank structures (as defined by Wolosz , 1992a). The ecological zonation of reef building species both within mounds and across reef tracts due to environmental gradients is a well known feature of both Recent and ancient reefs (Wilson, 1975; James, 1983). Hence, the unusual nature of the mound building community at the LeRoy Bioherm (as compared to the typical rugosan dominated Edgecliff mounds), and the size of this cladoporid dominated mound, suggests that environmental conditions in the area must have differed in some way from those prevalent at the other Edgecliff bioherm locations.

B3: THE LEROY BIOHERM REVISITED: EVIDENCE OF A COMPLEX DEVELOPMENTAL HISTORY

STOP 1.00 LEROY BIOHERM
Stop at curve, road leading into quarry is overgrown. Walk past east side of house on north side of road to dirt road. Follow dirt road into quarry.
NOTE: PLEASE ASK PERMISSION AT HOUSE BEFORE ENTERING PROPERTY.
The most direct entrance into the quarry is down the talus slope which covers much of the east wall bioherm. From the top of the quarry wall the central bioherm can clearly be seen in the center of the quarry pit. The core facies of the bioherm are massive, weathering to a dark gray and can be easily differentiated from the bedded flanking facies which are very light gray to almost white limestone (see text for description). The quarry walls consist of highly fossiliferous Edgecliff shallow marine facies.

B4: LATE SILURIAN SEDIMENTATION, SEDIMENTARY
STRUCTURES AND PALEOENVIRONMENTAL SETTINGS WITHIN AN
EURYPTERID-BEARING SEQUENCE [SALINA AND BERTIE GROUPS],
WESTERN NY AND SOUTHWESTERN ONTARIO, CANADA
RICHARD D. HAMELL
48 Saranac Street
SAMUEL J. CIURCA, JR.
Department Geoscience
1000 East Henrietta Road
One of the most fascinating aspects of Late Silurian sedimentation in the Appalachian Basin is the occurrence ofthick sequences of evaporites and associated sediments. In western New York and southwestern Ontario, Canada, these sequences comprise the Salina and Bertie Groups and have been, or are economically important sources of both halite and gypsum.
Our particular interest in this evaporite sequence stems from the peculiar occurrence of complex eurypterid assemblages distributed, cyclically, throughout the sequence. If there is any hope of understanding the true habitat of the eurypterids, it will come from a more detailed examination of all lithofacies and contained sedimentary structures. We continue in this paper, and associated field trip, to call attention to the great variety of rock types, sedimentary structures, unusual fossil assemblages, and their stratigraphic and geographic distribution.
In the following text, it will be noted that eurypterids are mentioned throughout. This is not only an attempt to illustrate the importance of the eurypterid faunas found throughout the region, but to show their intimate association with part of the sedimentological record reviewed. Furthermore, because eurypterids are structurally complex; because they molted frequently during their growth; and because they often became disarticulated, eurypterid parts were subjected to fragmentation, redistribution by sorting and orientation, and even comminution as bioclasts. We suggest that these processes are important sedimentological features worthy of observation and study. Likewise, "algal" stromatolites, those mound like to laminar structures so often encountered in some of the eurypterid beds, are seen herein not only as important biological structures that affected the local sedimentological regimes, but as contributors to the regional sediments as particles and pieces ripped from the biostromes and redistributed, along with eurypterid debris, into flat-pebble conglomeratic accumulations within, primarily, the waterlimes (e.g. Ellicott Creek Breccia) and the finely-crystalline dolostones (e.g. Victor Dolostone) of the Fiddlers Green Formation (Bertie Group).

B4: LATE SILURIAN SEDIMENTATION, SEDIMENTARY
STRUCTURES AND PALEOENVIRONMENTAL SETTINGS WITHIN AN
EURYPTERID-BEARING SEQUENCE [SALINA AND BERTIE GROUPS],
WESTERN NY AND SOUTHWESTERN ONTARIO, CANADA

STOP 1. OATKA CREEK AT GARBUTT
Excellent exposures of the Syracuse Fm. (Salina Gp.) occur along Oatka Creek both upstream and downstream of the Union Street Bridge over the creek. Over 50 feet of strata have been measured along the south side of the creek and the entire section appears to represent the Upper Syracuse Formation. Included are argillaceous, thin-bedded (flaggy) dolostones, massive limestones and dolostones (particularly along the banks ofthe creek), thin waterlime units and evaporites. The site was extensively mined for gypsum and the ruins of some of the buildings that were constructed are still visible on the north side of the creek just upstream from the bridge. Note the buildings were constructed with glacial erratics and slabs of Syracuse Formation. An account of the gypsum mining activity here, and in nearby areas, can be found in Newland (1929).
Very few fossils have been described from the Syracuse Fm. of the region. The eurypterid Waeringopterus was traced into western New York but has not been found along the Oatka Creek Valley (Ciurca, 1990, p. D10). Eurypterus has been found in a waterlime bed immediately upstream from the bridge. The exposures in the wall on the south side of Oatka Creek have yielded cephalopods and Medusaegraptus. An algal stromatolite horizon occurs near the top of the section.

STOP 2. VICTOR DOLOSTONE ERRATICS
Massive Victor Dolostone (middle member ofthe Fiddlers Green Fm.) can be observed in the waterfall at nearby Buttermilk Falls. The large erratics at the driveway exhibit the finely crystalline character typical of the Victor Dolostone. Bedding planes are often covered with the small brachiopod, Whitfieldella.

STOP 3. THE NEID ROAD QUARRY
This quarry exposes a fine section of the Late Silurian Bertie Group overlain by massive beds of the cherty Onondaga Group. The erosional Silurian-Devonian unconformity is well displayed here. The quarry floor is comprised of the upper waterlimes of the Fiddlers Green Fm. and includes an eurypterid fauna consisting of Eurypterus and Dolichopteris. The irregularity of portions of the floor is due to algal stromatolite mounds. Salt hoppers and associated relict halite structures are common at this level.
Brecciated waterlimes (Ellicott Creek Breccia) are present just above the quarry floor, particularly at the north wall of the quarry. Immediately overlying this is 5-8 feet of the Scajaquada Formation, an argillaceous, mostly thin-bedded dolostone containing several chert nodule horizons.
The Williamsville Formation, here a particularly drab gray to cream colored dolostone, is exposed along the north wall of the quarry. Fossils are exceedingly rare in this unit. Only phyllocarid telsal spines and a few articulate brachiopods have been found here.
The Akron-Cobleskill is nearly missing from the section. At nearby Buttermilk Falls, the Scajaquada, Williamsville and Akron Fms. are all missing, the Onondaga Limestone rests directly upon the Fiddlers Green Formation.

STOP 4. STEAM LOCOMOTIVE AND SHOVEL
Turn-of-the-century (1902) steam shovel used quarrying on right.

STOP 5. FORT HILL WATERLIME
Uppermost Camillus Fm. is well-displayed in the roadcuts along both sides of NY19. At the top is a thin waterlime unit, the Fort Hill Waterlime. The overlying Oatka Formation is concealed by overburden. The Fort Hill Waterlime is considered the base ofthe Bertie Group and bears an Eurypterus Fauna (Ciurca, 1973, p. D3). It is also accessible near the base of nearby Buttermilk Falls.

STOP 6. BUTTERMILK FALLS
Follow the abandoned railroad east to Oatka Creek. A trail to the base of Buttermilk Falls is located on the west side of the valley, north of the railroad bridge over the creek. Note: walls of the gorge are steep. The safest trail to the bottom enters the gorge about 1.25 mile north of the falls.
Buttermilk Falls is capped by resistant Onondaga cherty limestone. The underlying Bertie Group forms the reentrant at the unconformable contact with the Onondaga Group.
At creek level is uppermost Camillus Formation (Salina Group). The Bertie Group here starts with the Fort Hill Waterlime, a complete section of the Oatka Formation, and most of the Fiddlers Green Formation. The Scajaquada, Williamsville and Akron Formations are missing due to erosion prior to the deposition of the Middle Devonian Onondaga Limestone.

B5: FIELD STUDIES OF THE MIDDLE DEVONIAN LUDLOWVILLE-MOSCOW SEQUENCE IN THE GENESEE AND SENECA VALLEYS, NY
STEPHEN M. MAYER
Fredonia, NY 14063
Numerous authors have studied and described in detail the unique depositional environments and the excellent fossil preservation found in the Middle Devonian Hamilton Group sediments of New York State (Grabau, 1899; Cooper, 1930; Grasso, 1973; Brett and others, 1986; Savarese and others, 1986). The advancement of high resolution stratigraphic mapping has permitted detailed correlations of facies divisions in the uppermost Ludlowville Formation across western and central New York (Mayer, 1989; Mayer and others, 1994). The focus of this field trip is to examine the spatial and temporal sedimentary relationships as well as the abundant and well preserved fossils in the Upper Ludlowville-Lower Moscow Formations of the Hamilton Group; in particular, the uppermost Wanakah Shale, Jaycox Shale and Tichenor Limestone Members in the Genesee and Seneca Valleys (Figure 1 ).
Note: Road log and stop descriptions accompanying this article follow paper by Brett and Baird (this volume).
DEPOSITIONAL SEQUENCES, CYCLES, AND FORELAND BASIN DYNAMICS IN THE LATE MIDDLE DEVONIAN (GIVETIAN) OF THE GENESEE VALLEY AND WESTERN FINGER LAKES REGION
Dept. of Earth & Environmental Sciences
GORDON C. BAIRD
Late Middle Devonian (late Givetian) deposits in the Genesee Valley central Finger Lakes region are represented in ascending order by the Moscow Formation of the Hamilton Group, the Tully (Limestone) Formation, and the lower third of the Genesee Formation. This succession records a dramatic facies transition from fossiliferous subtidal shelf mudstones in the Moscow Formation through outer lagoonal-to-shelf carbonate deposits in the Tully Limestone, into black shales recording anoxic basinal conditions in the Genesee Formation. The Tully-Geneseo succession records a dramatic shift from carbonate platform conditions to a deep-water, anoxic foredeep setting due to inferred flexural loading of the craton by a pulse of orogenic thrusting (Ettensohn, 1985, 1987).
The Moscow-lower Genesee stratal succession yields abundant and diverse fossils ranging from robust, shallow water forms to delicate taxa that lived under conditions of near-anoxia. Moscow and Tully biotas are highly diverse and have been well known since the publication of James Hall's "fourth district" report in 1839. Well preserved fossils can be collected at all of the field stops.
Strata discussed herein were deposited as muds in a foreland basin setting linked to a key phase of the Acadian Orogeny, a collision event involving the "docking" of one or more microcontinents in what is now New England and the central Atlantic states (Faill et al., 1978; Woodrow 1985; Ettensohn, 1985, 1987). Orogenic uplift and overthrusting in the tectonic settings to the east and southeast of New York State led to flexural downbending of the craton in eastern North America (Quinlan and Beaumont, 1984; Beaumont et al., 1988). This loading produced a foreland basin characterized by greater regional subsidence and often greater water depths (Figure 1). Erosion of orogenic highlands in the east led to the formation of progradational complexes ("Great Catskill delta") which filled in the Devonian shelf seas associated with the foreland basin, thus producing the Devonian stratal record in New York State, Pennsylvania, Maryland, and Virginia. In actuality, several inferred collision and overthrusting events are believed to have produced tectophases of overthrust induced basin deepening and progradational basin-filling (Ettensohn, 1987; Ettensohn and Elam, 1985). A mainly quiescent phase at the end of Tectophase II is recorded by the upper Hamilton Group (Moscow Formation). However, the Tully-Genesee transition records a grand deepening and progradational pulse associated with the onset of Tectophase III.
The Devonian ("Catskill") clastic wedge provides a classic example of an ancient deltaic complex. Because orogenic events took place to the east, sediments supplied to the basin came from the eastern Acadian mountain belt. This is typically, though not always, reflected in the eastward-thickening of sediments within the Catskill clastic wedge. It is also reflected by west-to-east facies changes (limestone-to-terrigenous sediment, shale-to-siltstone, siltstone-to-sandstone, etc.) at almost all stratigraphic levels. These diachronous facies shifts are well displayed in the Devonian time-rock stratigraphic chart for the state (Rickard, 1975). The Catskill Delta is also a story of numerous isochronous events: evolutionary and immigration (epibole) events, volcanic eruptions, and sea level changes can be traced stratigraphically over long distances.
In this paper, we will focus on the record of sea level oscillations which have left a detailed record of sedimentary cycles during the Late Givetian Age (approximately 380-375 million years ago). Numerous thin limestones, marine erosion surfaces, and stratigraphically condensed intervals record sediment starvation events associated with transgression events; these are well displayed in strata discussed herein. Recent advances in our understanding of Catskill Delta depositional processes involve the use of principles of sequence stratigraphic mapping.
The purpose of the present paper and associated field trip is fourfold: first, we document a rich assortment of shelf-to basin facies which is characterized by a broad array of Devonian fossils; second, we illustrate advances in stratigraphy which have been developed with the past few years, particularly involving application of sequence stratigraphy concepts to Paleozoic foreland basin deposits; third, we illustrate patterns of differential subsidence and migration of the foreland basin centers; finally, we illustrate several excellent Late Givetian sections within two hours' drive of Rochester which yield abundant, diverse, and well preserved fossils for the Devonian enthusiast.
We have chosen to describe Moscow subdivisions in some detail in the present paper in order to provide the details upon which our interpretations are based and as a guide to the various fossil bearing levels to aid paleontologic studies. Because most horizons are laterally traceable for tens of kilometers we have followed the practice of assigning many bed names for those divisions. This is not intended to overwhelm the reader with detail but to facilitate unambiguous communication about the many levels. The more general reader may wish to bypass these sections and read the sections on sequence and cycle interpretation.

B5: FIELD STUDIES OF THE MIDDLE DEVONIAN LUDLOWVILLE-MOSCOW SEQUENCE IN THE GENESEE AND SENECA VALLEYS, NY

Cross Honeoye Creek in approximate pre-glacial valley of
Genesee River

Cross tributary of Conesus Creek

Middle Devonian Jaycox Shale
Minor hill slope exposures of Middle Devonian of Jaycox Shale; middle Devonian; excavation for I-390 in 1979 yielded a prolific fossil assemblage at this site.

Cross Conesus Creek (swampy stretch)

Middle Devonian Centerfield Limestone
Farm on right side borders Conesus Creek at Triphammer Falls, about 0.25 miles north of Triphammer Road; this is a classic locality for the Middle Devonian Centerfield Limestone.

OPTIONAL STOP A. WHEELER FALLS
For optional stop pull off on shoulder of Rt. 39. Walk back to path along fence to west banks ofJaycox Creek.
(See Description for Jaycox Creek)

STOP 1: JAYCOX RUN
White Devon Farm on left. Pull off on right shoulder near gateway into pasture, walk straight west from gate through pasture to clump of oak trees along Jaycox Creek, south branch for Stop 1 . Note: Visitors must obtain permission from the Wadsworth Estate, Geneseo to study this locality.
Locality
Exposures along the south (main) fork of Jaycox Creek, on the property of William P. Wadsworth (White Devon Farm), 0.4 km (0.25 mi) west of NY Rt. 39 about 0.8 km. (0.5 mi) north of Nations Road, Geneseo, Livingston County, N.Y. (Geneseo 7.5 ft Quadrangle, 1950).
References
Cooper (1930), Grasso ( 1 973), Baird (1979). The following description is from Brett and Baird ( 1981).
Descriptions of Units
Jaycox Creek exposes a nearly continuous section of the Ludlowville (Centerfield, Ledyard, Wanakah, and Jaycox members) and lower Moscow (Tichenor, Deep Run, Menteth, and basal Kashong members) formations (Figure 10). Exposures to be examined during the field trip are those in the upper portion of the Jaycox ravine associated with a series of three low waterfalls held up the thin limestone bands; a low upper falls is formed by the Menteth Limestone, a middle falls by the Tichenor Limestone, and the highest, lower falls by a calcareous band in the Jaycox Member.
The Jaycox through Menteth interval will be examined in detail. Faunal lists for these units are given by Grasso ( 1973). Units are described in ascending order as follows.
Ludlowville Formation
Wanakah Shale Member: The upper 4 m (13.2 ft) of the Wanakah Shale Member are visible below the lowest falls in Jaycox Creek. This constitutes an undifferentiated interval of medium gray fissile, friable shales with a low diversity fossil assemblage. Ambocoelia umbonata, Mucrospirifer, chonetids, and Athyris, the small rugose coral Stereolasma, trilobite remains (Phacops and Greenops), and various bivalves are common. No calcareous bands or concretions are present in this portion of the Wanakah Shale.
Jaycox Shale Member: Baird (1979) selected this creek exposure as the type section for his Jaycox Shale Member, the uppermost member of the redefined Ludlowville Formation. At this locality, the Jaycox consists of about 4 m (13.2 ft) of soft, bluish-gray shale with abundant thin fossil-rich horizons (biostromes) and calcareous bands (see article by Mayer, this volume).
The basal Hills Gulch bed of the Jaycox Member (Unit A) is a bioturbated, silty, argillaceous limestone band 30-35 cm (~1 ft.) thick, which grades upward from the calcareous uppermost Wanakah Shale (Figure 11). This blocky band which caps the lower falls of Jaycox Creek is notably rich in brachiopods (Mucrospirifer, chonetids, and Mediospirifer), bivalves (Actinopteria, Modiomorpha, Paleoneilo, and Cypricardella), and gastropods (Mourlonia and Palaeozygopleura). This bed has yielded exceptionally well preserved bivalves, including rare specimens in burrow positions. The bed contains numerous spreiten of Zoophycos. Westward this bed merges into a large coral-bearing unit resembling the overlying Tichenor limestone. Coral beds which occur at several levels within the Jaycox Member (Units 8-C) contain assemblages very similar to those of older Centerfield Limestone, including a diversity of corals such as Eridophyllum, Heliophyllum halli, and the colonial form Heliophyllum confluens which is essentially restricted to this member. Large favositids and Thamnoptychia are also common at several levels within the Jaycox Member. Fossil layers contain abundant fenestellid bryozoans and large runner-like columns of crinoids modified as hold fasts (stolons). Diagnostic brachiopods of the Jaycox include Parazyga hirsuta and Pentamerella pavillionensis. These brachiopods are restricted to coral rich facies and recur only in association with biostromes (Centerfield Limestone, Jaycox Shale, Tichenor Limestone, and Windom coral beds).
Moscow Formation
Tichenor Limestone: The Tichenor Limestone (Unit D) constitutes a 30 cm ledge-forming band of medium gray, buff-to rusty weathering biomicrite (pack-or grainstone). As elsewhere, the Tichenor is an encrinite with abundant rugose and tabulate corals. The basal surface of the Tichenor Limestone represents a minor disconformity (Baird, 1979). Undersurfaces of projecting ledges, which can be examined in detail at this locality, show an irregular, sharp contact with the underlying Jaycox Shale. Very large hypichnia, probably crawling furrows similar to Cruziana, occur abundantly on the undersurface of the Tichenor.
The upper contact of the Tichenor Limestone at Jaycox Run is gradational through 15 cm of calcareous shale into the overlying Deep Run Member.
Deep Run Shale Member:
Between the middle and upper falls, Jaycox Creek bed exposes 2.5 m (8.25 ft) of medium gray, calcareous mudstone of the Deep Run Member. These mudstones are distinctly harder (more calcareous) than most of the Jaycox Shale and break with irregular fractures due to the lack of fissility. Lower Deep Run shales (Unit E) contain a fauna similar to that of the Jaycox coral biostromes, including Heliophyllum, Eridophyllum, (but H. proliferum rather than H. confluens) and large favositid heads. Small mounds of fistuliporoid bryozoans project upward some 50 cm into the base of the Deep Run Member; these are exposed in the floor of Jaycox Creek. Associated with these mounds are abundant large stems and stoloniferous holdfasts of camerate crinoids; calyces of Dolatocrinus, Megistocrinus, and other crinoids occur rarely in the basal Deep Run. The Deep Run Member is particularly noted for the large size of its trilobites. Specimens of Phacops rana, Greenops boothi, and Dechenella sp. are abundant and are typically very large relative to those found in underlying and overlying shale units.
The upper beds of the Deep Run (Unit F) are sparsely fossiliferous bluish gray shale mudstones containing very abundant limonitized (pyritized) sinuous burrows. Occasionally, vague Zoophycos traces can be observed. These sparsely fossiliferous shales contain scattered stringers and lenses of large crinoid columnals and fenestellid bryozoans suggestive of storm lags. The Deep Run Member is gradational into the overlying Menteth Limestone Member.
Menteth Limestone Member: The Menteth Limestone (Unit G) which caps the uppermost falls in Jaycox ravine, consists of approximately 28-30 cm of light gray, buff-weathering irregularly bedded, strongly bioturbated calcisiltite (biomicrite). The lower contact of the Menteth is gradational, but the upper surface is sharply defined and hummocky suggesting a slight discontinuity or burrowed omission horizon. The Menteth contains a very abundant and often well preserved traces (Zoophycos) and scattered body fossils including spiriferid brachiopods, rare corals, and large trilobite fragments.
Kashong Shale Member: Only the lowest 30 - 50 cm of bluish gray, calcareous Kashong Shale (Unit H) crop out in Jaycox Run. These basal shales contain abundant fossils including the ramose tabulate coral Thamnoptychia, various bryozoans, brachiopods, camerate crinoids, and large trilobites.
Discussion
The basal Moscow Formation in the Genesee Valley represents a slightly different spectrum of environments. This sequence begins with the Tichenor Limestone which, as in most western N.Y. localities rests with marked disconformity on the Ludlowville Formation (Baird, 1979). Presumably, a portion of the upper Jaycox interval has been removed by submarine erosion prior to the deposition of the Tichenor. The Tichenor Limestone was probably deposited in a high energy, above wave base setting, as indicated by winnowing of fines, abrasion of fossil fragments, vague cross lamination, and overturned favositid coral heads. This unit is inferred to represent the shallowest water conditions in the entire sequence exposed at Jaycox Run. Gradation of the Tichenor into the overlying Deep Run calcareous mudstone indicates a return to lower energy, mud depositional conditions. The Deep Run thickens rapidly eastward into a lentil of calcareous mudstone which attains a maximum thickness of about 18 m (59.4 ft) near Canandaigua Lake and then thins again eastward toward Cayuga Lake where the Deep Run pinches out (Baird, 1979). This lenticular configuration suggests active subsidence of a localized basin following the Tichenor deposition. The Deep Run locally contains cross laminated calcisiltite and calcarenite lenses which were probably transported into the depositional basin from nearby shoal regions during severe storms. Hence, the unit was deposited below normal wave base, but within reach of storm waves.
Deep Run mudstones grade upward into the Menteth Limestone, a uniformly thin (30-40 cm) but very widespread carbonate unit. The Menteth is a thoroughly bioturbated calcisiltite and is inferred to represent the terminal phases of infilling of the Deep Run depositional basin. Processes of sediment winnowing, probably aided by biological activity, became dominant over deposition of clays, resulting in a thin, lag deposit of skeletal debris and carbonate silt. Locally, coral beds developed on the upper surface of the Menteth. Menteth Limestone, in turn, grades upward into Kashong mudstones which faunally and lithologically somewhat resemble portions of the Deep Run. The entire Deep Run-Kashong interval (equals Portland Point of earlier workers; Baird, 1979) is inferred to represent deposition during a generally regressive interval. The sequence is bracketed by units which yield evidence of deposition under shallow water conditions. Minor oscillations of environmental conditions may have been the result of regional subsidence or downwarp of a shallow basin or trough.

To south is Wadsworth estate with ancient white oak trees

Genesee Fm Penn Yan
Beginning of Dewey Hill roadcut; Genesee Formation
(mainly Penn Yan dark gray shales)

STOP 2. FALL BROOK, GENESEO
Walk across highway and enter pasture along Fall Brook at gateway. Proceed on foot upstream to exposures.
Locality
0.37 mile east of U.S. 20A and 39 and below Fall Brook Falls, Geneseo, Livingston County, N.Y. (Geneseo 7.5 ft Quadrangle, 1950).
References
Cooper (1930), Baird ( 1 978), Baird and Brett (1983). The following description is from Brett and Baird (1981).
Description of Units: This stretch of Fall Brook exposes the upper portion of the Middle Devonian (Givetian) Moscow Formation (Windom and Kashong Shale Members) as well as the overlying Upper Devonian (Frasnian) Genesee Group (Figure 12).
Low cut banks along Fall Brook near U.S. 20A expose the upper 1.7 m (5.6 ft) of the Kashong Shale Member. This unit is comprised of sparsely fossiliferous, bluish gray mudstone with abundant pyritic tubular burrows. Body fossils include large ramose bryozoans, the brachiopods Lingula and Tropidoleptus, rare Dipleura trilobites, and phyllocarid fragments.
The disconformable contact with the overlying Windom Shale Member is exposed here and consists of a mudstone band approximately 10 cm-thick. This unit contains an admixture of reworked Kashong and Windom fossils and small phosphatic steinkerns and nodules (Little Beards phosphate bed). This heavily bioturbated sediment has been interpreted as a biogenically blurred unconformity or "stratomictic discontinuity" (Baird, 1978). The zone of phosphatic pebbles in the upper Kashong has been traced from Erie County, eastward to Owasco Valley, and is inferred to represent a widespread disconformity within the Moscow Formation (Baird, 1978). The informal "Unnamed Member" is absent here, having been cut out by erosion beneath the Little Beards bed.
Overlying the phosphatic pebble bed is typical basal Windom Shale: soft, medium gray shale with abundant specimens of Ambocoelia umbonata. A calcareous bed rich in trilobites occurs about 20 cm. above the Little Beards phosphatic nodule bed. Aside from the basal 30-50 cm, the lower 4.5 m (14.9 ft) of the Windom, are largely covered with slumped talus and are not accessible at Fall Brook. However, a complete Windom thickness of 15.63 m (51.6 ft) was measured at this locality.
The Windom section continues upstream at the base of a high cliff face on the northern side of Fall Brook. The lowest unit exposed here is soft shale rich in Ambocoelia brachiopods which may occur in small prod-like concentrations. The overlying Bay View bed consists of medium gray calcareous and very fossiliferous mudstone. Abundant fossils include Pseudoatrypa, Mucrospirifer consobrinus, Protodouvillina, the rugose corals, Stereolasma and Amplexiphyllum, crinoid columnals, and abundant Phacops trilobites. This unit is gradationally overlain by a band of medium gray calcareous shale and argillaceous limestone, approximately 40 cm-thick, which forms a falls in the creek bed. This is gradational above and below into less calcareous mudstone and contains abundant crinoid columnals in stringers, the small rugose coral Stereolasma, and fragmentary and complete specimens of the trilobites Phacops rana and Greenops boothi. Trace fossils in form of pyritic, sinuous burrows are very abundant in this zone. This bed is traceable into the "Smoke Creek bed" of Erie County, NY (Brett, 1974; Baird and Brett, 1983). The unit, in turn, is gradationally overlain by gray, calcareous and relatively fossiliferous mudstone with a fauna resembling that of Unit A which grades upward into darker, less fossiliferous shale.
A band of darker gray, relatively hard, fissile shale, forms a slight projection in the bank in some areas about 8 m (26.4 ft) above the base of the Windom. This interval (the Fisher Gully beds) contains abundant Emanuella praeumbona, large specimens of Ambocoelia umbonata, and occasional Leiorynchus and Spyroceras. It is overlain abruptly by a bed of crumbly medium gray mudstone packed with fossils including Cystilphylloides, Helioplyllum, and other large rugose and tabulate corals, atrypid brachiopods (Pseudoatrypa and Spinatrypa), Mediospirifer, and at least 55 other species of invertebrate fossils. Unit E, which occurs 8.57 m (28.3 ft) above the base of the Windom at Fall Brook, has been designated the Fall Brook coral bed closely resembles that of the slightly older Bayview coral bed and indicates a recurrence of nearly identical environmental conditions under which coral biostromes developed widely in western N.Y. The Fall Brook bed has been traced from Central Genesee county, eastward to Seneca Lake, a distance of approximately 90 km (56 mi). Large rugose corals are restricted to a 30-40 cm-thick band, however, other fossils including small rugose corals (Amplexiphyllum and Stereolasma), Pseudoatrypa, Mediospirifer, Douvillina, abundant crinoid columnals, and bryozoans persist upward for approximately 1.5 m (5 ft) into the overlying mudstone. This richly fossiliferous, but non-coral bed assemblage has been termed the Taunton beds by Baird and Brett (1983). The upper portion of the Taunton interval bears three zones of large, calcareous, nonseptarian concretions. Fossil bands run continuously through concretions, which indicates possible relationship between carbonate diagenesis and organic remains.
A thin (30 cm-band) of argillaceous limestone containing abundant small rugose corals (Stereolasma) and a few atrypid brachiopods Spezzano Gully bed occurs about 11 m (36.3 ft) above the base of the Windom Shale at Fall Brook. This unit grades upward into dark gray, slightly calcareous, petroliferous shale with abundant pyritic sinuous burrows and occasional nodules of pyrite and scattered fossils including Stereolasma and Pseudoatrypa.
The upper Windom Shale at Fall Brook consists of very dark gray fissile, pyritic shale (Gage Gully Bed). This shale is generally sparsely fossiliferous, but some layers contain abundant Allanella tullius, small Ambocoelia, Devonochonetes, and rare Leiorhynchus and E. praeumbona. A zone of pyritized fossils near the top of this interval has yielded nuculid bivalves, the trilobite Greenops boothi, the nautiloid Spyroceras, and rare large specimens of the goniatite Tornoceras cf. T. uniangulare. The highest beds of the Windom are black, platy shale with Allanella tullius. The contact between these beds and the overlying Geneseo Black Shale is often difficult to recognize in the Genesee Valley area because their lithologies are similar. However, the Geneseo is somewhat harder, weathers rusty and is more petroliferous than the upper Windom. The contact, here, as elsewhere in western New York, is sharp and unconformable.
Small lenses of Leicester Pyrite generally less than 10 cm-thick, occur at the Windom/Geneseo contact. The Leicester in this area contains abundant tubular pyrite, apparently reworked burrow fillings, as well as small brachiopods, nuculid bivalves, and rare nautiloids and goniatites from the erosionally truncated Windom (Brett and Baird, 1982).

STOP 2A. Scenic overlook of Fall Brook Gorge
Pull off at wide area along shoulder; walk up bank to right and proceed down dirt path to brink of Fall Brook Falls.
Dark shales on upper creek banks are West River Member of Genesee Formation falls is capped by Genundewa Limestone (20 in-thick). Caution: Stay back from edge, vertical drop of over 100 feet. (Possible lunch stop).

Cross Fall Brook

Upper end of Jaycox Creek tributary
Genundewa Limestone in exposed south of road.

Cross Conesus Creek
Outlet from Conesus Lake flows into the Genesee River.

Valley of Honeoye outlet creek.

View of Bristol Hills to south

Turn right for classic Windom localities
Rt. 64 to right leads south into Bristol Valley and classic Windom localities; near this location the "Unnamed member" is becoming truncated.

Type locality of the widespread Centerfield Limestone is on Schaeffer Creek north of Rt. 20

Cross Schaeffer Creek

Creek to left exposes Levanna black shale.

Cross Hopewell Ravine
Creek just below 20 exposes Jaycox and Tichenor members, small but excellent outcrop.

Cross Flint Creek

Large landfill site on right

Pre-Emption line
Pre-Emption line is an old western boundary line of Massachusetts territory.

Crossing Wilson Creek
Downstream is a large waterfall over Centerfield Limestone; top phosphatic bed is exposed near the Pre-Emption Road bridge.

Benton Run on left exposes nearly complete Ludlowville Formation.

STOP 3. KASHONG CREEK, LOWER FALLS
Locality
Exposures along the bed and banks of Kashong Creek just south of Kashong Road and 1.5-2.0 km (0.9-1.2 mile west of NY 14, township of Geneva, Seneca County, NY (Geneva South 7.5' Quadrangle, 1953).
References
Description of Units
This creek section is, arguably, one of the most complete upper Hamilton sequences exposed in the Finger Lakes Region; it is a classic reference section and the type locality for the Kashong Shale Member. Nearly the entirety of the Ludlowville and Moscow formations are exposed on Kashong Gully. We will examine the Moscow Formation in detail, commencing with the Tichenor Limestone which caps the highest waterfalls (10 m, 33 ft) in the glen; a somewhat lower (8 m, 26 ft) waterfall 400 m upstream from the latter, shield up the Menteth Limestone Member, and a third very low falls (approximately 2 m, 6.6 ft high) is formed by the resistant upper phosphatic shell bed at the top of the Kashong member and the overlying basal siltstone beds of the Canandaigua Member. A short distance upstream from this uppermost falls the section ends and the creek flows on glacial till.
The Hamilton beds in this area are gently deformed by Alleghenian (?) folding and faulting. The creek cuts most perpendicularly through a small anticline-syncline pair near the Kashong shale type section; the axis of the syncline is approximately at the low falls over the Kashong/Windom contact beds (discussed above); this contact is exposed again about 100 m upstream on the opposite (western limb) of the syncline, at the position of the old bridge across the creek. The bulk of Kashong section is exposed downstream from the small falls on the strongly west dipping eastern limb of the syncline. The crest occurs just downstream (east) of the high Menteth waterfalls. Below that falls the creek flows down the gentle east limb dip slope on the lower Deep Run beds for about 100 m (330 ft) before descending over the high Tichenor capped waterfalls. A relatively large down-to-the east normal fault with about 20 m (66 ft) displacement and minor splay faults occur near the mouth of Kashong Creek, but will not be examined on this trip.
The Tichenor through basal Windom sequence will be described and examined in detail; lower stratigraphic units at the base of the high Tichenor waterfalls are accessible by a steep (dangerous!) pathway down the south side of the gully or by walking upstream from the mouth of the Kashong Glen; however, we will simply observe these units from the top of the waterfalls. Stratigraphic units are described below in ascending order.
Ludlowville Formation
Upper Wanakah Shales: The lowest stratigraphic units observable in this part of the gorge are medium to dark gray shales on the upper Wanakah Member. These shales outcrop below a smaller waterfall 100 m (330 ft) downstream from the large Tichenor-capped falls; this latter falls is capped by silty, calcareous mudstones of the basal Jaycox Member (correlative with Unit A of the Jaycox run description; Stop 10, page 86). Upper Wanakah at the base of this falls consists of relatively fossiliferous, gray shale characterized by an abundance of small Pleurodictyum corals, brachiopods (such as Athyris, chonetids, and Ambocoelia), and Phacops trilobites. This sequence is capped by a fossil hash bed, identified by Baird (1981) as the Bloomer Creek bed. Overlying this layer in the face of the small waterfall are 2 m (6.6 ft) of dark gray to nearly black shales, bearing Leiorhynchus, small Tropidoleptus and small ambocoeliids.
Jaycox Member: The face of the high waterfalls and the creek-bed down stream to the cap of the next small falls expose a light bluish gray mudstone of the Jaycox Member. The lower half of this sequence consists of alternating calcareous mudstone and fossil rich limestone layers; these latter have a diverse fauna of abundant fenestrate and fistuliporid bryozoans, corals, especially Trachypora, brachiopods such as Tropidoleptus and Longispina, and abundant crinoidal debris. The upper Jaycox beds (upper half of falls face) consist of sparsely fossiliferous, hard, blocky, calcareous mudstone containing scattered very large specimens of the tabulate coral Pleurodictyum. The uppermost few centimeters of the Jaycox beds are visible at the top of the waterfalls.
Moscow Formation
Tichenor Limestone: This is a very widespread, thin (0.5-1 m, 1.7-3.3 ft) carbonate interval, traceable from Lake Erie, eastward at least to Chenango Valley; east of Cayuga Lake. (Baird, 1979; Griffing, 1994). The Tichenor is sometimes referred to as the basal bed of the "Portland Point" Member (Baird, 1979) At Kashong Glen this member, which crops out just upstream from the brink of the highest waterfalls, consists of thin bedded argillaceous, crinoidal packstone. The Tichenor is highly fossiliferous, characterized by large crinoid columnals and bryozoans with a few solitary, large rugose and tabulate corals.
In the Seneca Valley, the Tichenor does not form a compact, sharply based ledge, as it does at localities both east and west of this area. In fact, the basal disconformity which characterizes the Tichenor at all other locations here is either very cryptic or absent, and the lithology closely resemble that of more fossiliferous beds in the under-and overlying Jaycox and Deep Run members.
Deep Run Member: Overlying the Tichenor is about 10 m (33 ft) of hard, blocky, calcareous mudstone referred by Cooper (1930) to the Deep Run abundant, poorly preserved Zoophycos trace fossils. However, beds occurring about 1-2 cm above the Tichenor Limestone are highly fossiliferous, biostromal, argillaceous limestones resembling the Tichenor. The creek flows on dip slope of these units exposing relatively large bedding planes; these display small mounds of fistuliporoid bryozoans and crinoid columns (up to half meter in length); some of these columns form rhizomatous ("runner") holdfasts. Other common fossils include fenestrate and sulcoreteporid bryozoans, varied brachiopods, bivalves, large trilobites and well preserved (but difficult to extract) calyces of crinoids and blastoids. The large size of many fossils (especially trilobites) indicates favorable environments in terms of food supply, as might be expected in shallow muddy areas; however, the rarity and scattered to patchy distribution of fossils in most of the Deep Run Member suggests that colonization of the sea floor by benthos was sporadic and probably limited by soft, unstable substrate and/or high turbidity near the sea floor.
Note the considerably greater thickness of the Deep Run at Kashong Glen than at Jaycox Run (Stop 1). The Tichenor and Menteth limestones converge and eventually merge both east west of this area.
The Deep Run wedges out abruptly both east and west of the Finger Lakes. This unit which closely resembles the calcareous mudstone facies of the older Mottville, Centerfield, and Jaycox carbonate intervals apparently characterizes deposits of a shallow rapidly subsiding trough bordered by very shallow (within wave base), crinoidal sandy shoals.
The Deep Run facies is considered to represent a wedge of rapidly-deposited, fine-grained sediments which were winnowed from adjacent shallow tichenor-type shoal environments that bordered a central trough. Inter-fingering of Tichenor-like lithologies with the barren mudrock indicates close proximity of the two types of facies.
Menteth Limestone Member: This is compact, 30 cm-thick silty; siliceous, heavily bioturbated limestone which caps the moderately high waterfall west (upstream) of the Tichenor falls. This limestone is particularly characterized by an abundance of Zoophycos burrows, Mucrospirifer, Spinocyrtia, and large specimens of Phacops.
The undersurface of the Menteth in some areas appears gradational with the underlying Deep Run; elsewhere, as here, it is undulating and displays large scoured out burrow fillings indicating some erosion prior to its deposition.
This unit appears nearly identical throughout its outcrop despite thickening and thinning of synjacent shales (see Jaycox Run, Stop 1, descriptions). We have interpreted this unit as a winnowed, bioturbated calcisiltite reflecting reworking of Deep Run muds, following infilling of a subsided trough.
Kashong Shale Member: The Kashong Member abruptly overlies the Menteth. It consists of bluish gray mudstones which are somewhat softer, less calcareous and silty than the Deep Run Member, with horizons of small irregular ovoid to pipe-like carbonate concretions, silty limestones and highly fossiliferous calcareous mudstones. Fossils are moderately abundant in the bluish gray mudstones and include, particularly, brachiopods (Tropidoleptus, "Spirifer" marceyi, and Mucrospirifer), the tabulate coral Pleurodictyum, bryozoans, bivalves, large trilobites, including Dipleura, phyllocarids, and crinoid stems.
The Kashong at this location, displays repetitive, cyclic motifs, consisting of: (a) sparsely fossiliferous blue gray shale, (b) zones of grotesquely- shaped carbonate concretions, capped by, (c) thin beds of burrowed calcisiltite resembling the Menteth Limestone, and/or (d) complex condensed shell beds. There are two complete cycles and two thin incomplete cycles within the member. These are interpreted as minor regressive, shallowing upward hemicycles, the complex shelly phosphatic pebble beds record sediment starvation and/or winnowing associated with cycle reversals.
A widespread, complex shell bed occurs within the Kashong Shale about 2.6 m (8.6 ft) above the base. Informally named the "Rhipidomella-Centronella" bed (or R-C bed) this unit contains a great abundance and diversity of fossils including the nominal brachiopods and the large spiriferid Spinocyrtia (commonly highly corroded), Douvillina, varied bryozoans, bivalves, gastropods, trilobites, and crinoid debris. This bed, which locally approaches the appearance of the Tichenor Limestone (and was formerly considered to be the top of the Portland Point Member; Cooper, 1930; Baird, 1979) appears to represent a widespread interval of winnowing and shell concentration, perhaps associated with a minor shallowing cycle. It is overlain by bluish gray shale resembling the lower Kashong.
Unnamed Shale Member: Only the basal 2 m (6.6 ft) of this previously unrecognized member of the Hamilton Group are exposed at this section. The unit commences with the Barnes Gully phosphatic pebble bed, a slight discontinuity may exist. At eastern localities a tongue of typical Kashong mudstone with Tropidoleptus is present between the phosphatic bed and the Curtice Road bed. This bed resembles burrowed calcisiltites of the Menteth, and consists of Zoophycos-burrowed calcareous silt, with a fauna of Spinocyrtia, Mucrospirifer, chonetids, Pholidostrophia and other brachiopods.
Also, the basal "unnamed" unit locally displays a shell bed especially rich in strophomenid brachiopods and containing rare rugose corals. The silty bed shows a gradational top, passing upward into silty shales with a deeper water biofacies of small chonetids which then passes up into soft medium gray shales with very abundant Longispina. This reflects a deepening event, stronger than those of the lower Moscow, which resulted in a return of lower aerobic to dysaerobic, deeper water environments in western New York. This transgression apparently explains the recurrence of litho- and biofacies closely similar to those of the lower Hamilton formation. We presume that such facies coexisted with the shallower water facies of the Moscow interval, but that they were displaced southwestward into the basin axis and do not appear anywhere within the New York outcrop belt during deposition of the Jaycox to Kashong interval.
Discussion: The upper Hamilton Group in the vicinity of Kashong Glen displays several differences from outcrops of the equivalent interval to the west (Genesee Valley, see Stop 1). Several units (e.g., upper Ludlowville, Tichenor, and Deep Run shales) show subtle differences indicating deeper water in the Kashong Glen area than at sites either east or west of this region. For example, the Wanakah and Spafford-equivalent shales which are represented by fossiliferous, gray mudstones at Genesee Valley, and by comparable but siltier facies at Cayuga Lake, here are composed mainly of dark gray, fissile shale with a low-diversity, Leiorhynchus-dominated fauna; this seems to indicate deeper, more dysaerobic water in an area centered in the Seneca Valley than in the bordering areas. Similarly, the Tichenor-Deep run units are differentially thicker here than at Genesee Valley or the Cayuga region; they are also less carbonate rich; in the case of the Tichenor the limestone is a pack- or wackestone in the Seneca Lake region but a grainstone both to the east and west. It is less rich in large corals and crinoids and appears to be nearly conformable above and below whereas to the east and west it is bounded by an erosional unconformity at the base and, locally, on the top. Again, this seems to indicate an area of differentially deeper, quieter water near the Seneca Lake meridian.

STOP 4: KASHONG CREEK AT BELLONA
Exposures at waterfalls along Kashong Creek 0.1 km east (downstream) from Pre-emption Road and upstream to 0.2 km west of road, town Bellona, Yates County, N.Y. (Stanley 7.5' Quadrangle, 1952).
Reference
Heckel (1973)
Description
This outcrop provides an excellent section of the top of the Hamilton Group (Windom Shale), the unconformable overlying Tully Limestone, and the basal Genesee Group (Geneseo Shale). This classic section was critical in Heckel's (1973) subdivision of the Tully Formation into the lower and upper members separated by an unconformity.
Windom Shale: Lowest units exposed in this portion of Kashong Creek are fossil-rich medium bluish gray shales of the upper Windom Member ("Taunton Beds"); this 7 m (23 ft) interval contains many thin, lenticular brachiopod-, rugose coral-, bryozoan-bearing shell beds, mutually separated by sparsely fossiliferous mudstones. Thicker beds probably record relatively long spans of slow deposition during which shells accumulated and were reworked by occasional strong storm waves; overlying mudstones apparently represent rapid influxes of mud that terminated shell buildup.
The uppermost 2 m (6.6 ft) of the Windom display marked change to dark gray or nearly black shale with diminutive brachiopods. This records a relatively strong transgressive (deepening event) that occurred near the close of Hamilton deposition.
These beds display a sharp, erosional contact with the overlying Tully limestone. An interval of diastrophic upwarp and erosional truncation, perhaps associated with subaerial exposure prior to Tully deposition. Nonetheless, despite this evident break both the Windom and the lower Tully belong to the same conodont subzone (middle P. varcus subzone).
Tully Limestone: At the falls the light-gray, micritic Carpenter Falls bed (0.6 m-thick) of the Tully Lower Member, overhangs the Windom Shale; its basal surface displays large elongate burrows up to 8 cm. across, that were produced in over compacted Windom muds and subsequently infilled with Tully matrix. The Carpenter Falls bed contains the index brachiopod Hypothyridina, as well as atrypids, small rugosans, trilobites, and crinoid debris. At the upper surface of this bed Heckel observed a widespread mid-Tully erosion surface, and, at this locality (upstream from Pre-emption Road Bridge), he noted possible truncated stromatolites at this surface. Hard fossiliferous wackestones, of the Taughannock Falls bed (Tully Upper Member) overlies this intraformational disconformity. The Taughannock Falls bed is capped by a thin, shaley bed with very abundant large rugose corals (Heliophyllum and Cystiphyllolides) and Favosites termed the Bellona coral bed for this excellent exposure. Upstream (west) from Pre-emption Road, the large corals are clearly visible on a large bedding plane on the creek floor. The Bellona coral bed has proven to be a key mappable unit. The Bellona bed is abruptly overlain by a thin (0.6 to 1.0 m) remnant of the Moravia bed; the upper Moravia bed and Fillmore Glen bed are absent here.
The top of the Moravia bed is marked by an erosion surface that, in this area, shows a thin layer rich in crinoidal debris, conodonts, fish bones, pyrite and glauconite; a few thin stringers of this lithology recur in the overlying black Geneseo Shale. This lag debris is believed to be a lateral equivalent of the Leicester Pyrite which is know to overlie the erosional top of the Tully about 12 km (7 miles) northwest at Gorham. This bed has yielded conodonts diagnostic of the upper hermanni-cristatus subzone, whereas the underlying Moravia bed is of the middle varcus Zone age. Evidently, a considerable hiatus separates these units, during which time the upper Tully units were erosionally bevelled, prior to Geneseo deposition.
Geneseo Shale: The erosional upper surface of the Moravia bed, or, locally, the Bellona bed, is sharply overlain by platy, black Geneseo Shale, which is fossiliferous, except for the stringers of reworked crinoidal debris, mentioned above. This unit records major deepening of the Taghanic onlap. It is presently considered of the latest Middle Devonian (late Givetian) age.

Entrance to Oak corners Quarry on left.
This is an excellent Onondaga Limestone section (Ver Straeten et al. trip - this guidebook).

Cross Flint Creek; outcrops of upper Silurian dolostone

Bertie\Bois Blanc\Onondaga
A right turn here leads up to cuts below Thruway in Bertie\Bois Blanc\Onondaga

Outcrops of Onondaga Limestone in Flint Creek left side

Nedrow shale along Flint Creek
Driveway to left leads to outcrops of Nedrow shale along
Flint Creek; (see Ver Straeten, this volume).

Field exposure of Camillus Shale on left

Rising onto moraine; rest stop at top

B6: DEVONIAN FOSSIL LOCALITIES IN WESTERN NEW YORK

STOP 1. JAYCOX RUN
Turn right into driveway of "White Devon Farm" (watch for sign). Park along left side of driveway. Be careful to leave ample room for horse trailers and traffic.
Entrance to the Wadsworth property and Jaycox Run is through a farm gate immediately across the road. Walk across the field to Jaycox Run (NW corner). Last person through gate MUST secure and fasten!
Locality: Exposures along the south (main) fork of Jaycox Creek, on the property of William P. Wadsworth (White Devon Farm), 0.4 km (0.25 mi) west of N.Y. Route 39, about 0.8 km (0.5 mi) north of Nations Road, Geneseo, Livingston County, New York.
References: Cooper (1930), Grasso (1973), Baird (1979). The following description is from Brett and Baird (1981 a).
Description of Units: Jaycox Creek exposes a nearly continuous section of the Ludlowville (Centerfield, Ledyard, Wanakah, and Jaycox members) and lower Moscow (Tichenor, Deep Run, Menteth, and basal Kashong members) formations. Exposures to be examined during the field trip are those in the upper portion of the Jaycox ravine associated with a series of three low waterfalls held up by thin limestone bands. A low upper falls is formed by the Menteth Limestone, a middle falls by the Tichenor Limestone, and a highest, lower falls by a calcareous band in the Jaycox Member.
The Jaycox through Menteth interval will be examined in detail. Faunal lists for these units are given by Grasso (1973). For further detail of unit descriptions see Brett and Baird in Miller, M.A. (ed.), 1986.

STOP 2. FALL BROOK.
Turn around in driveway of the "Christiano Alfalfa Milling Co." (mustard colored sign on left) and park along guardrail facing uphill. Entrance to Fall Brook is at the uphill end of the guardrail.
Locality: Exposures along the bed and banks of Fall Brook 0.2-0.6 km (0.1-0.37 mi) east of U.S. Route 20A-N.Y. Route 39 and below. Fall Brook Falls, Geneseo, Livingston County, New York (Geneseo 7.5' Quadrangle, 1950).
References: Cooper (1930), Baird (1978), Baird and Brett (1983). The following description is from Baird and Brett (1981 b).
Description of Units: This stretch of Fall Brook exposes the upper portion of the Middle Devonian (Givetian) Moscow Formation (Windom and Kashong Shale members) as well as the overlying Upper Devonian (Frasnian) Genesee Group.

STOP 3. TAUNTON GULLY
Pull off road just past small white house on right; park along roadside next to small field adjacent to house, before guardrail.
Walk back along edge of field, cross railroad tracks immediately behind the house and continue to far left-hand comer of field. Access to Gully is on small path through woods.
Locality: Gully exposures approximately 0.1 miles west of Route 36,2.4 miles south of intersection of N. Y. Routes 36 and 63
References: Kirchgasser (1973; "Stop 6"), Patchen and Dugolinsky (1979; "Stop 35")
Description: About 25 feet of uppermost Windom Shale is exposed upstream from the railroad. There are a number of concretionary horizons occurring with layers of pyrite nodules. The shales below the first waterfall are blue-grey, shaly mudstones becoming darker and more compact further up in the section.
Faunal diversity is greater in the lower shales, consisting of bryozoan beds, stereolasmatid corals, trilobites, crinoids, and a rich brachiopod fauna. Above the first falls the fauna consist of most Phacops fragments and stereolasmatid coral horizons.
The Leicester Pyrite overlies the Windom. It is 4-6 inches thick and poorly exposed. Heavy collecting is discouraged to preserve the extent of the exposure.
The Geneseo and Penn Yan shales are exposed above the Leicester Pyrite (60-70 feet) and capped by one foot of Genundewa Limestone at the upper falls.

STOP 4. BROWN'S CREEK
Proceed 0.4 miles to large, grey, metal pole bam on left just after bend in road (split-rail fence; parking on left side of road on either side of fence). Take wooden stairwell down to house and creek exposure.
Locality: Stream excavation 0.1 mile north of York Road East, about 0.4 mi east of Town of York on property of Jim Nardi
References: None for Ledyard Shale at this locality as it is a relatively new exposure
Description of Units: Until recent excavations, the Ledyard Shale was only poorly exposed upstream from the classic Centerfield/Levanna locality. The horizon studied on this trip is an excavation (widening) of the creek bed approximately 15 feet above the Ledyard/Centerfield contact. Of special interest are concretionary horizons and a horizon containing large Phacops trilobites. These are generally dark grey shales with many Ambocoe/ia brachiopods.

Field Trip Guidebook for the 67th Annual Meeting of the
Edited by
John I. Garver
Jacqueline A. Smith
For the combined meeting of the
67th Annual meeting of the New York State Geological Association &
26th Annual meeting of Eastern Section of the American Association of Petroleum Geologists
Sponsored by
New York State Geological Survey/State Museum and Union College
Hosted by
Geology Department, Union College, Schenectady, NY
This guidebook was published by the New York State Geological Association. Additional copies may be obtained from the Executive Secretary of the NYSGA:
Bill Kelly, Executive Secretary
New York Geological Survey
Room 3140 Cultural Education Center
Albany, New York, 12230
The Geology Department at Union College is proud to co-host the sixty-seventh annual meeting of the NYSGA and AAPG Eastern Section. Together this combined meeting has brought together academics, students, teachers, petroleum geologists, and environmental geologists. The Geology Department at Union College is happy to be a co-sponsor and co-host of the NYSGA meeting this year because it has been quite some time since we have been able to host such an event. The last time the annual NYSGA meeting was held at Union was 30 years ago when the principal movers in the Department were Philip Hewitt and Leo Hall (see Shaw, this volume). Shortly after this meeting the Geology Department was effectively disbanded and only recently came to life in 1985 after the College received a generous donation from a Geology alumnus. Now ,with four permanent faculty, one visitor, and several adjuncts, it is safe to say that we're back for good!
Since the last time NYSGA was held at Union, the Geological Sciences have experienced a major transformation. The first twenty of those years were clearly dominated by the then new plate tectonic paradigm. During the last ten years, and especially the last five years, we have seen quite a dramatic change in the focus of the geological sciences. Due in part to a number of external factors, the geologic community has placed a greater emphasis on issues associated with global change, hydrology, and environmental geology. This shift, has been away from the more traditional areas in geology such as field based studies in stratigraphy, sedimentology, paleontology, and structural geology. There is little doubt that NYSGA guidebooks reflect the focus and ideas of the times and if one compares the focus of the trips in this meeting to those in the guidebook for the previous NYSGA meeting at Union in 1965, you will see just how much our science has changed.
In assembling the trips for the 67th annual meeting of the NYSGA we tried to balance three important factors: our unique and exciting geologic setting; the breadth of interests of our members; and, importantly, the availability of field trip leaders. Certainly in terms of the first two factors, I feel that we have succeeded and we are looking forward to an exciting meeting!
The geologic setting of the lower Mohawk Valley is ideal for teaching and research. The lower Paleozoic stratigraphy has a regional tilt to the south so one can examine the Grenville-aged rocks of the Adirondacks to the north (Whitney and Olmstead, this volume; McLelland, this volume; Kelly and Hill, this volume), Cambro-Ordovician carbonates and clastic rocks in the Mohawk Valley (Garver, this volume; Kidd and others, this volume), and Silurian and Devonian rocks in the Catskill Mountains to the south (Friedman, this volume; Wolosz and Paquette, this volume; and Ver Straeten and Brett, this volume). The lower Paleozoic stratigraphy in eastern New York is punctuated by thick synorogenic sequences deposited during the Ordovician Taconic Orogeny and the Devonian Acadian Orogeny. To the east of the tilted lower Paleozoic stratigraphy, deformation in the section increases towards the front of the Taconic Allochthon where it and underlying rocks were deformed during the Taconic Orogeny (Hollocher, this volume; Kidd et al., this volume; Friedman, this volume). In the Taconic Allochthon, Cambro-Ordovician deep-water sedimentary rocks have been placed over shallow-water sediments of the Cambro-Ordovician margin.
The surficial and glacial geology in this area is as impressive and diverse as the bedrock geology. Ice dynamics related to the obstructing effects of the Adirondack Mountains resulted in non-uniform migration of ice sheets that coalesced south of the Adirondack massif only to encounter the Catskill Mountains to the south (Dineen and Hanson, this volume). During retreat, glacial Lake Albany (and its relatives) covered much of the Capital District and left an impressive sequence of glacial lacustrine deposits (Wall and LaFleur, this volume). During and after the most recent glaciation, karst and caves formed in the local carbonate strata, resulting in important landform development and interesting problems in hydrogeology (Rodbell and Hays, this volume; Rubin et al., this volume; Rubin, this volume). The long history of industry in the area and demand for space and water have resulted in some unique environment geology (Smith and Eslinger, this volume; Maswick and Snow, this volume; Hewitt, this volume). Finally, the neotectonic setting of eastern New York is examined in a unique trip aimed at understanding the seismic hazards in Columbia County (see Nottis and Cadwell, this volume).
It has become clear that the education of educators is and will continue to be an important priority for both Academe, government, and industry. With this in mind we have included several trips aimed at earth science teachers (Garver, this volume; Hollocher and Hollocher, this volume; and Kelly and Hill, this volume, and others) and we hope that many of the teachers who go on the field trips participate in the special one day workshop which will be held in Monday following the NYSGA meeting.
Finally, I would like to personally thank all of the people that have made this guidebook happen. First and foremost are the trip leaders who have spent a considerable amount of time putting together these trips and to my co-editor, Jacquie Smith, who helped with the endless task of reigning in papers and keeping track of things. Thanks are also due to the Organizing Committee and Committee Chairs for the combined NYSGA & AAPG Eastern Section meeting for their support, suggestions, and recommendations. Among them, Ken Johnson (Skidmore College), the General Chair, deserves special praise for keeping us together and focused for the committee meetings which periodically met for more than one year prior to the actual meeting. He also deserves special recognition for finally getting on EMail during that time (you can personally thank him at kjohnson@skidmore.edu). I would also like to thank Bill Kelly (N.Y. State Geological Survey), who is the N.Y.S.G.A. Executive Secretary, for his important contributions which include, but are not limited to advice and planning the logistics of putting this guide together. Finally, Gretchen Turner did a superb job handling the problems that editors face in terms of communication with authors and the nuts and bolts of putting the guide together.
To all who are just about to embark on the 67th annual NYSGA meeting -- have a great time and enjoy the fall foliage!
President, NYSGA, 1995
Union College
October, 1995
PLEASE READ THIS!
Landowners and outcrop defacement
In preparing this guidebook we asked the authors to do their best to ascertain landowner status at each stop. We have done this because increasing number of problems have arisen between landowners and geologists - in some cases geologists are no longer permitted to visit some localities in the Mohawk Valley. Additionally, a number of classic and important outcrops have been defaced, marked, or heaped with garbage by overzealous visitors who must leave their mark on every outcrop visited. Please pay careful attention to landowner status and cultivate a relationship with the landowner if you plan to use an exposure from year to year. Also remind your trip participants to use have respect for the future geologists who will visit these geological sites. Thank you.

A1: SEISMIC RISK ASSESSMENT OF COLUMBIA COUNTY, NEW YORK
GARY N. NOTTIS AND DONALD H. CADWELL
Room 3140 CEC
In 1994 the New York State Geological Survey began a pilot study to assess earthquake hazards in New York State, on a county by county basis. This effort was modeled after studies done in Portland, Oregon, and Los Angeles, California. The goals of this work were to produce:
- an earthquake ground-motion response map,
- an earthquake-induced landslide-potential map,
- an earthquake-induced liquefaction map, and
- a combined earthquake hazards map.
Our analyses were done as a function of glacial landforms. The maps produced are a result of computer-based analyses of earthquake strong ground-motions, soil depth profiles, soil engineering properties, and topographic slopes. These maps are intended to aid civil engineers, building designers, and emergency managers on the subjects of earthquake preparedness and hazard mitigation.
Columbia County was chosen for the initial study because of its proximity to the Capitol District, and also because of the quantity and quality of geologic data already available. This pilot study was a learning experience. We are still in the process of analyzing the collected data, and the preliminary results are encouraging. During this field trip we will show why such studies are needed, how these studies should be conducted, common problems, and how the results of these studies can be applied.

A1: SEISMIC RISK ASSESSMENT OF COLUMBIA COUNTY, NEW YORK

Knickerbocker Lake, over hill to left.
Kames, kettles and kettle lake.

Outwash sands and gravels
Outwash sands and gravels, prograding southward to delta at Kinderhook, deposited in Glacial Lake Albany.

STOP 1. DEMONSTRATION OF SEISMIC LINE
The Pleistocene equivalent to the Kinderhook Creek deposited the large delta complex into Glacial Lake Albany 18,000 to 15,000 years ago. Abundant meltwater was transported from both the retreating Wisconsinan glacier terminus and the bedrock uplands toward the delta. The present channel of the Kinderhook Creek is incised 17-20 m (50-60 ft) into the delta (Figure 6) and the location of this seismic line is on the floodplain. Water well information suggests bedrock is 12-24 m ( 35-55 ft) beneath the floodplain.

Martin Van Buren Historic Site

Columbia County Airport

As we descend the hill, note the old marsh ahead of us.

STOP 2: Clay Pit
This clay pit, shown in Figure 7, is owned by the City of Hudson, and permission should be obtained prior to visiting the site. Today we will be able to see a small remnant of the original working area. These alternating bands of dark clay and lighter colored silt-clay are rhythmites, rhythmically deposited fine-grained lacustrine sediment. If the dark and light couplet represent an annual winter and summer accumulation, then they are varves. This 10 m exposure has couplets 2-5 cm thick and could represent 200-300 years of sediment accumulation into Lake Albany. When wet, these clays are very plastic.
1. What do you suppose would happen during an earthquake to the dams of Underhill and Oakdale ponds?
2. What would be the fate of these clay banks?

Note the landfill to the right.

Note Underhill Pond to right.
This is a man-made pond within the gully.

Turn left into entrance for Fireman's Home -- Lunch
Note: To eat lunch at the Pavilion it is necessary to obtain permission in advance.
If time permits, the Fireman's Museum is excellent.

STOP 3: Discussion of buildings, etc., City of Hudson.
See Figure 7 for specific location. Discussion will concentrate on types of building structures, and location of emergency services.

STOP 4: Home damaged by land slump.
NOTE: This road log has stopped several miles from the property owner of STOP 4 because this is a private residence and the NYSGA trip has been given special permission to visit. The owners prefer not to be disturbed by an onslaught of people in the future.
The damage resulted from land failure on October 7, 1983, coinciding with the 1983 Blue Mountain Lake, magnitude 5.1, earthquake, with the epicenter 180 kilometers away.

A2: WOLLASTONITE DEPOSITS OF THE NORTHEASTERN ADIRONDACKS
PHILIP R. WHITNEY
Room 3140 CEC
Albany NY 12230
JAMES F. OLMSTED
48 Haynes Road
Plattsburgh NY 12901
The presence of wollastonite near Willsboro in the northeastern Adirondacks (Fig. 1, 2) has been known since the early nineteenth century. The earliest reference to it in the geologic literature is by Vanuxem (1821). For over a century, the wollastonite was of little interest except as a mineralogical curiosity. Mining on a small scale began at Fox Knoll near Willsboro in 1938, with the wollastonite being used as a flux for arc welding. In 1951, the Cabot Corporation gained control, and began underground mining in 1960. Interpace Corporation took over and expanded operations in 1969. Product development resulted in uses in ceramic bodies and glazes, as a reinforcing filler in plastics and resins, and as a substitute for short-fiber asbestos. The operation, now known as NYCO, was purchased in 1979 by a subsidiary of Canadian Pacific (US), Processed Minerals Inc. Open pit mining at the Lewis (Seventy Mountain) Mine, ten miles southwest of Willsboro, began in 1980 and in 1982 the underground operation at Willsboro was closed. Both properties are now owned by NYCO Minerals, Inc., a subsidiary of Fording Coal Company of Calgary, Alberta.
The Willsboro deposit was mentioned briefly by Buddington (1939, 1950) and Buddington and Whitcomb (1941); the geology is given in more detail by Broughton and Burnham (1944). Putman (1958) described several occurrences of wollastonite in the Au Sable Forks and Willsboro quadrangles, including those at Willsboro, Deerhead, and Lewis (Figure 2). De Rudder (1962) studied the mineralogy and petrology of the Willsboro ores, and attributed them to contact metamorphism with localized alumina metasomatism. Oxygen isotope work by Valley and O'Neil (1982) demonstrated extensive metasomatism involving meteoric water.

A2: WOLLASTONITE DEPOSITS OF THE NORTHEASTERN ADIRONDACKS

STOP 1: METANORTHOSITE OF THE WESTPORT DOME
Massif anorthosites are plagioclase-rich igneous rocks. Their origin is controversial; the debate is summarized in Ashwal (1993). Most current models involve variations on this theme: Large volumes of mantle-derived basaltic magma fractionate in the upper mantle or lower crust toward an aluminum-rich residuum. Appreciable contamination may take place from partially melted lower crust. As the magma rises through the crust, plagioclase crystallizes to produce a crystal-rich magma or mush which is emplaced in the middle or upper crust. Further fractionation may follow emplacement; iron-enriched residual liquids may sink or be expelled by filter pressing.
In the Adirondack anorthosites, plagioclase occurs in two forms: dark-gray megacrysts and smaller, light-gray to white interstitial grains. Compositions range from An42 to An60, most commonly An48 to An55. Antiperthitic megacrysts are locally common. The interstitial feldspar, which may include some K feldspar, consists of varying proportions of crushed megacryst ("protoclastic") plagioclase and feldspar crystallized from residual liquid. In addition to plagioclase, the principal minerals of igneous origin are orthopyroxene, clinopyroxene, and iron-titanium oxides. Metamorphic minerals include garnet (in the more iron-rich varieties), hornblende, and biotite.
The Westport Dome is the largest anorthosite body in the Adirondacks outside the Marcy Massif. This exposure, near the southern end of the dome, illustrates the outcrop-scale lithologic variability common in Adirondack anorthosites. Gabbroic anorthosite is present in the eastern third of the cut; anorthosite in the remainder; textures and abundance of megacrysts vary widely. Note the vertical, ENE-trending ductile shear zone and the small, deeply weathered fault near the middle of the cut.

STOP 2: ANORTHOSITIC GNEISS
Cuts along the E side of the parking area expose strongly foliated anorthositic gneiss. The foliation here ranges from nearly horizontal to gently north-dipping; a NNE-trending lineation, common throughout the northeastern Adirondacks, is visible on some surfaces. Intense ductile deformation is common along the margins of the dome but is also present in the interior in zones such as this one. The timing of this deformation is unclear save that it postdates consolidation of the anorthosite. Walk north 0.1 miles along the road. On the left, blasted outcrops of anorthositic gneiss contain an irregular, tabular body of garnet-two pyroxene-plagioclase gneiss with minor K feldspar. "Jotunites" such as this one may be residual liquids from the anorthosite.

Moderately deformed anorthosite
Outcrops on left are moderately deformed anorthosite containing lenticular dark patches rich in pyroxene that may be the remnants of large pyroxene oikocrysts.

Good view from a small rise
Crest of small rise overlooking the Champlain Valley with Lake Champlain and the Green Mountains of Vermont visible in the distance.

To the right, a fine view of the Green Mountains.
To the right, a fine view of the Green Mountains, from Mt. Mansfield (L) to Camel's Hump (R).

This is private property.
This is private property: be sure to obtain permission from NYCO before entering. Proceed through the gate and about 0.4 miles up this road to the lower portal of the Willsboro Mine.

STOP 3: WILLSBORO MINE
The Willsboro deposit is located near the base of the ore-bearing zone (OBZ), separated from the underlying metanorthosite by, at most, several tens of feet of amphibolite. Average strike of foliation and compositional layering within the OBZ is N 60°-65° W with considerable local variation; dips range from 15°-35° north. DeRudder (1962) cites drill core evidence for as many as seven ore layers, with maximum thickness of the principal ore horizon on the order of 50 feet. Numerous small brittle faults and unmetamorphosed mafic dikes (Isachsen et al., 1988) cut the ore.
We will examine exposures at both the lower and middle portals of the now-abandoned underground mine. The area around the middle portal was formerly operated as an open pit. Observe the straight, sharply defined garnet-pyroxene rock (GPS) layers in the ore as well as diffuse compositional layering within the ore; the latter shows complex folding in a few places. One GPS layer appears to crosscut foliation and compositional layering at a low angle. At contacts of the ore with gabbroic anorthosite or amphibolite, discontinuous layers and lenses (boudins?) of pale orange-brown garnet rock ("garnetite") are locally present. If time permits, we will traverse part of the OBZ overlying the ore, to examine a complex section of interlayered rocks including garnetite, amphibolite, gabbroic anorthosite gneiss, mafic calcsilicate rocks, and olivine metagabbro.

Outcrops of unmetamorphosed carbonates
Outcrops of unmetamorphosed carbonates in the woods just east of this intersection attest to the presence of a N-S normal fault, mapped by Buddington and Whitcomb (1941), that separates the Precambrian and Paleozoic rocks in this area. Going North on Fish and Game Road, the outcrops on the left are Precambrian marbles and gneisses.

Long Pond on the left.
The outcrops along this road are gabbroic and anorthositic gneisses with some interlayered metasedimentary rocks, occupying a structural saddle between the Westport dome to the south and the Port Kent dome to the north.

STOP 4: MARBLE XENOLITH IN JOTUNITE
Climb the bank on the right side of the road. At the top, climb over the fence and examine the rocks at the top of a large roadcut on the northbound lane of I-87. Please exercise great caution near the edge of the cut cliff facing the Northway. Also, please do not climb down to road level, as it greatly distresses the State Police.
The white rock is a large xenolith of calcite marble surrounded by mafic gneiss. The marble contains varying amounts of phlogopite, diopside, chondrodite, grossular, graphite, and sulfides. Phlogopite also occurs in clots a few centimeters across. A few lens-like masses of amphibolite are folded in a manner that suggests the "fishhook" forms commonly found in other intensely deformed marbles. Diopside-plagioclase rock with very calcic plagioclase occurs near contacts with the host rock; identical rocks are found in the OBZ upsection from the Willsboro Mine.
The host rock is strongly foliated and lineated garnet-pyroxene-K feldspar-plagioclase gneiss, similar to the jotunites at Stop 2. This is one of many locations where carbonates in contact with rocks of the anorthosite suite have not developed large amounts of wollastonite. The outcrops on both sides of Route 9 at this location are also jotunites; those on the east side contain a layer or lens of garnet-rich gabbroic anorthosite gneiss, as well as masses of quartz (quartzite xenoliths?).

Strongly foliated gabbroic anorthosite gneiss
Roadcuts beneath and to the south of the I-87 overpass are strongly foliated gabbroic anorthosite gneiss with garnet- and pyroxene-rich zones.

Cliffs are granitic gneiss; road level crops are anorthosite gneiss
The cliffs on the right, on the east face of Pokomoonshine Mountain, are granitic gneiss; the outcrops at road level are gabbroic anorthosite gneiss.

Entrance to Pokomoonshine State Park on right.

Outcrops of fault breccia on right.
A NNE-trending brittle fault roughly follows the road here.

Alternate stop if time permits.
Park on the left, just North of a small outcrop of gabbroic anorthosite gneiss. Cross a narrow strip of woods to the southbound lane of the Northway. The roadcuts here are anorthositic gneisses with marble inclusions. Again, please remain on the top of the outcrop, and do not cross the road.

STOP 5: GABBROIC AND ANORTHOSITIC GNEISSES
Two fault-shattered outcrops on the West side of the road and one on the East contain very strongly foliated gabbroic and anorthositic gneisses. We map these as part of the OBZ, at the NW comer of the Westport Dome. The gabbroic gneisses contain millimeter-scale layers of garnet-pyroxene rock. Marble is present at the base of the outcrop on the East side. The more northerly outcrop on the West contains an undeformed hornblende-quartz-feldspar pegmatite. If wollastonite-rich layers are present in this section of the OBZ, they are not exposed.

Gate to Lewis Mine.
Get permission from NYCO before proceeding. The large open pit of this operating mine is a short distance up the gravel road.

STOP 6: LEWIS MINE
While the immediate geologic setting of the Willsboro deposit is well known (Putman, 1958; DeRudder, 1962; Olmsted and Ollila, 1988), that of the Lewis deposit is less clear due to lack of natural exposures in the immediate vicinity. The orebody strikes roughly E-W and dips gently south, approximately parallel to the topographic surface, on the south limb of an open, E-W trending anticlinal crossfold. On the west side of the open pit, where the ore is close to 80 feet thick, it is overlain by strongly foliated charnockite; to the east the overlying rock, where exposed, is mainly anorthositic gneiss. Throughout much of the present mine area, the ore was exposed at the erosion surface. When the overburden was removed to begin mining, a karst-like surface was present, owing to the fact that wollastonite is one of the few silicate minerals that are appreciably water-soluble. Based on drilling data and temporary exposures within the mine, the footwall appears to be amphibolite and gabbroic anorthosite gneiss.
The hills north of the mine are gently N-dipping gabbroic anorthositic gneiss, underlain by deformed olivine metagabbro of the Jay Mountain body; both of these units are structurally above the ore-bearing horizon. Unlike Willsboro, where the ore is at most a few tens of meters above the anorthosite of the Westport Dome, our mapping suggests that the ore at Lewis is underlain by a considerable thickness of mixed gneisses and metasedimentary rocks. At one point during mining, a 4-6 m wide unmetamorphosed diabase dike was exposed.
Throughout much of the Lewis orebody, ore is interlayered with straight, sharply defined, discontinuous GPS layers parallel to foliation in the ore. We interpret this as tectonic layering. The regional NNE lineation can be seen locally on foliation surfaces in the ore here and at the Oak Hill prospect two miles to the east. A few thin, discontinuous layers of pyroxene-plagioclase-sphene granulite, rimmed by garnet-rich GPS, are present locally within the ore. Toward the north end of the present pit, layering and foliation are less prominent and the ore is leaner, rich in pyroxene and grossularitic garnet. At the northwest corner, a folded dike of GPS clearly crosscuts foliation.

A3: GLACIAL DEPOSITS IN THE MOHAWK AND SACANDAGA VALLEYS OR A TALE OF TWO TONGUES REDUX
ROBERT J. DINEEN
Roy F. Weston
1 Weston Way
West Chester, PA 19380-1499
ERIC HANSON
Continental Placer
26 Computer Dr.
The purpose of this field trip is to examine the late glacial deposits of the Mohawk and Sacandaga Valleys, particularly the recessional and interlobate moraines preserved in the vicinity of Gloversville, NY. The glacial sediments exposed in the area were deposited during the waning stages of the last ice sheet, when the local topography split the thinning and wasting ice sheet into the Mohawk and Sacandaga glacial tongues. Sediment-laden meltwaters from these lobes deposited a complex of moraines and glacial lake sediments from Gloversville to Galway. The three-dimensional distribution of sedimentary facies record the demise of these tongues and provide a framework for one of the most productive aquifers in NYS.
This study focuses on three 7-1/2 quadrangles: Gloversville, Broadalbin, and Northville. Adjacent 7-112 minute quadrangles studied include Amsterdam, Tribes Hill, Galway, Jackson Summit, and Peck Lake (Figure 1).
The study of the glacial stratigraphy of the Mohawk and Sacandaga Valleys has enjoyed a resurgence in the past thirty years after a lull of nearly forty years. Brigham (1928) published a map and lengthy interpretation of the glacial deposits of the central and western Mohawk Valley. This map and its associated text stood as the "last word" until Robert LaFleur and his graduate students began to re-examine glacial deposits and glacial history of the area in the early sixties (LaFleur, 1965; Yatsevitch, 1968). Yuri Yatsevitch completed a Masters Thesis in 1968 that outlined the framework of the late Wisconsinan history of the valleys. LaFleur (1969, 1975, 1979, 1983) built upon Yatsevitch's thesis, paying particular attention to evidence for a Late Wisconsinan readvance (the Yosts Readvance) and the wide-spread distribution of a dark gray, clay-rich till (the Mohawk Till). Later, Dineen and Hanson continued LaFleur's and Yatsevitch's work while mapping for the New York State Geological Survey's Surficial Mapping Project (see Cadwell and Dineen, 1986). They refined the geologic mapping and stratigraphy in the eastern Mohawk Valley while Jack Ridge refined the mapping and stratigraphy in the western Mohawk (Dineen and Hanson, 1985; Muller and Ridge, 1986; Ridge, 1991; Dineen et al., 1992).

A3: GLACIAL DEPOSITS IN THE MOHAWK AND SACANDAGA VALLEYS OR A TALE OF TWO TONGUES REDUX

Crossing the western edge of the Hudson Lowlands.

Crossing the trace of the Hoffmans Fault.

We are proceeding across ground moraine
We are proceeding across ground moraine of Mohawk Drift. The hills are drumlins, many of which have stratified drift cores.

Crossing the Perth Recessional Moraine.

STOP 1: Town of Broadalbin (see Figures S-1 and S-2a).
This exposure is in the southeast, Mohawk Drift portion of the BIM. The eastern slope was the ice-proximal side. The area was overridden from the southeast by the Yosts Readvance. The overriding ice plowed into the moraine, shearing and displacing the drift to the northwest. The deposit later collapsed by normal faulting and slumping when the Yosts ice melted. The outwash and ice-contact stratified drift exposed in the pit was deposited by meltwater flowing east to west along the margin of the Mohawk tongue. This conclusion is based on cross-bedding and climbing ripple orientations.
In 1984, the Section exposed at the Town of Broadalbin Town Pit was as follows:
6 m: Top of section.
4.5 to 6 m: | 10 YR 6/4 Fine sand with little gravel, in planar beds and climbing ripple laminae. Contorted to the east. Upper 50 cm is massive and fissile.
4.5 m: | Disconformity.
3.5 to 4.5 m: | 10 YR 6/2 Climbing-ripple and ripple-trough-laminated fine sand with lenses of gravel near its base.
3.5 m: | Disconformity.
2.5 to 3.5 m: | 10 YR 6/4 Trough cross-laminated, fine to coarse sand with fine gravel in I to 3 m wide, 1 to 1.5 m deep channel fills inset into ripple laminated very fin e sand. The unit is contorted and overturned to the northwest and gravity faulted to the east. The upper 50 em is fissile and sheared. The unit contains lenses of coarsening-up, silty, sandy matrix-to clast-supported diamicts.
2.5 m: | Disconformity.
Base to 2.5 m: | 10 YR 6/4 Planar cross-laminated fine sand with lags of gravel on truncation surfaces. Ripple laminated to the east. Faulted down to the southeast.
A pit 70 m west of this Stop contained 5 meters of contorted, ripple-bedded sand. The upper portion of the sand was deformed by shearing, and was overturned to the northwest. The sand was overlain by 1 to 2 meters of compact, fissile, sandy matrix-supported diamict.

STOP 2: Scotia Sand and Gravel (see Figure S-1 ):
This subaqueous fan contains planar, trough, and ripple-laminated sand and silty sand. Cross beds suggest that the sand was deposited against the ice by meltwater flowing from the east and southeast. The Sacandaga tongue lies to the northwest, in the vicinity of the present shoreline of the Sacandaga Reservoir.

STOP 3: Herba Pit (see Figures S-1 and S-2b).
This exposure is in the northwestern portion of the BIM, on the Adirondack Drift side. The ice was on the northwestern side of the moraine. Many flow tills and a few compact lodgement tills are observed in this pit.
In 1983, the Section exposed at the Herba Pit was as follows:
9.7 m: | Top of section.
9 to 9.7 m: | 7.5 YR 6/8 Sand and silt matrix-supported diamict. Some cobbles are present.
8.6 m to 9 m: | 10 YR 6/3 Trough cross-bedded, cobbly gravel.
6 to 8.6 m: | 10 YR 7/6 Lenticular, trough cross-bedded, cobbly sand and gravel.
4.8 to 6 m: | 10 YR 5/4 compact, sandy matrix-supported, massive to laminated diamict. Lenses of fine sand are present.
3.9 to 4.8 m: | 10 YR 7/2 Interbedded sandy massive to planar-bedded diamict with greasy, rotten shale clasts. The lower 20 em is sheared.
3.9 m: | Truncation surface;
Base to 3.9 m: | 10 YR 7/2 Cross-bedded cobbles and sand. The cross beds dip 10 S80E.

STOP 4. Rex Excavating
This exposure is in the southwestern portion of the BIM, on the Mohawk Drift side. Southeast was the ice-proximal side. The pit contains several till and lacustrine sequences that suggest the ice margin was oscillating. It was overridden by the Yosts Readvance. A similar exposure lies 1.7 km to the east.
In 1984, the Section exposed at the Rex Excavating Pit was as follows:
11.3 m: | Top of section.
9.7 to 11.3 m: | 10 YR 4/2 silt matrix-supported diamict. The unit is faintly laminated with sand stringers at the base. The base has a sheared contact with:
8 to 9.7 m: | 10 YR 6/4 Irregularly-laminated fine sand and silt. Cobbles of rotten shale are present.
7.7 to 8 m: | 10 YR 4/6 Laminated, silt matrix-supported diamict.
6.6 to 7.7 m: | 10 YR 6/3 Planar-laminated fine sand with cobbles. Unit is locally cemented.
2 to 6.6 m: | 10 YR 5/3 Planar cross-bedded, gravelly sand with a trace of boulders. The cross beds dip 10 to 15 N60W.
Base to 2m: | 10 YR 5/3 Silt matrix-supported diamict with striated boulders.

STOP 5: Twin Cities Sand and Gravel (see Figures S-3 and S-2d)
This pit is in the distal portion of the BIM and contains distinct subaqueous fan features (foreset beds and starved ripples). Both gravity and thrust faults are common in the eastern (proximal) portion of the pit. Aeolian sand mantles the upper 4 m of the pit. The upper cross-bedded sand is the leading edge of an aeolian dune. The upper sandy diamict is wind-blown silt and sand.
In 1984, the Section exposed at the Twin Cities Sand and Gravel Pit was as follows:
14m: Top of section.
12 to 14m: 10 YR 5/4 Cross-laminated fine sand.
10 to 12 m: 10 YR 6/3 Laminated to massive (west to east) sand matrix-supported diamict. This unit fills in depressions in the lower unit. The top contact has a soil zone.
Base to 10 m: 10 yr 6/4 Planar cross-bedded fine sand with lenses of trough laminated medium to coarse sand. Faulted and interbedded with contorted lenses of silty matrix-supported diamict to the east.

STOP 6. Mayfield Pit (see Figure S-3 and S-2e).
This pit is in an esker that pokes above the Glacial Lake Sacandaga plain.
In 1984, the Section exposed at the Mayfield Pit was as follows:
6.5 m: | Top of section.
5 to 6.5 m: | 10 YR 7/3 Beds of contorted laminated fine to medium sand to thin rhythmically laminated, very fine sand to silt.
2 to 5 m: | 10 YR 7/3 Fining-upward, planar-bedded, imbricated cobbles to silt, beds dip 10 S50W.
Base to 2m: | Covered.

STOP 7. Bradt Pit (see Figures S-4 and S-2!)
This pit is a deep cut into a kame delta that was built into a 900 ft as! glacial lake, possibly an ice-marginal portion of Lake Gloversville. The exposure was 65+ m high and 350m long in 1984!
In 1984, the Section exposed at the Bradt Pit was as follows:
65 m: | Top of section
50 to 65 m: | 10 YR 5/4 Shallow, trough cross-bedded, fine to medium sand, some gravel grading down into fining upwards, 10 YR 6/2 planar cross- bedded boulders through coarse sand, dipping 5 to 10 S60E.
45 to 50 m: | 10 YR 6/4 Planar cross-bedded, fine to medium sand and ripple-laminated, gravelly, fine to medium sand, dipping 15 S30W.
30 to 45 m: | 10 YR 6/2 Coarsening upwards, planar cross bedded, cobbly, gravelly, fine to coarse sand, dipping 15 S50W. Cobbles are subangular to subrounded.
15 to 30 m: | 10 YR 6/4 Planar cross-bedded, fine to medium sand with trace cobbles. Beds dip 10 to 15 N60W.
Base to 15m: | 10 YR 6/2 Imbricated, open-work, subangular to subrounded boulders in 1 to 1.5 m cross beds. Imbrication dips N20E.

A4: LITHOFACIES AND STRUCTURE OF THE TACONIC FLYSCH,
MELANGE, AND ALLOCHTHON, IN THE NEW YORK CAPITAL DISTRICT
WILLIAM S.F. KIDD, ANDREAS PLESCHI
Dept. of Geological Sciences,
University at Albany,
Albany, NY, 12222
FREDERICK W. VOLLMER
Dept of Geological Sciences,
SUNY College at New Paltz,
New Paltz, NY, 12561
The Taconic Allochthon of eastern New York is bordered to the west by a zone of mid-Ordovician shale and greywacke turbidites, which are appropriately characterized by the term "flysch". These synorogenic deep-water clastics are now interpreted to represent the fill of the migrating flexural basin created by the advance of the Taconic thrust sheets onto the Cambro-Ordovician passive margin of eastern North America (Rowley and Kidd, 1981; Bradley and Kusky, 1986). The flysch is markedly diachronous, with a thick basal carbonaceous shale unit, the Utica Shale, and extends many hundreds of kilometers west of the present margin of the Taconic Allochthon. The Allochthon consists almost exclusively of sedimentary rocks that represent a sample of the continental rise part of the Cambro-Ordovician passive margin, and of the latest Precambrian-earliest Cambrian clastics of the late-stage rift fill, and rift to passive margin transition; all are strongly folded and have been transported westward on a complex system of thrusts at least 150 to 200 km relative to the North American craton (Bradley, 1989). In the New York Capital District, a zone about 16-20 kilometers wide of the Ordovician flysch adjoining the western margin of the Allochthon has also undergone strong deformation, including widespread conversion of once stratified rocks to melange, associated with the later stages of the Taconic Orogeny. It is the purpose of this guide and field trip to examine these rocks, to attempt to illuminate the structures which they contain, to try to roll back at least some of the nomenclatural and stratigraphic confusion they have suffered, and to place them in the larger regional context of the Champlain Thrust system.

LITHOFACIES AND STRUCTURE OF THE TACONIC FLYSCH,
MELANGE, AND ALLOCHTHON, IN THE NEW YORK CAPITAL DISTRICT

View over Mohawk to flat Schenectady Fm in south bank

STOP 1. View of flat-lying Schenectady Fm. flysch and shale
View of flat-lying Schenectady Fm. flysch and shale outcrop on south bank of Mohawk River from end of Brian Drive.
Outcrops are scarce in the belt of flat-lying to gently dipping greywackes and shales [flysch] east of the trace of the Saratoga-Ballston Lake normal fault. The best are in the south bank of the Mohawk River, and are not readily accessible to large groups. At this stop (see Figure 2 for location) a shaly unit of the Schenectady Formation flysch can be seen across the river underlying medium-bedded greywackes and shales with gentle west dips and no signs of internal deformation.
These rocks are autochthonous and have not been transported by thrusting during the Taconic Orogeny. About 300 meters to the east of this location, along the southern shore, there is an abrupt contact of these flat-lying strata with significantly folded and faulted thin-bedded greywackes and shales, defined by the first thrust fault encountered in a west-to-east transect. This is not clearly apparent from this viewpoint, but a representative outcrop of the folded and faulted flysch is seen at the next stop.

STOP 2. Folded and faulted flysch of Vischer Ferry Zone
Outcrop along north shore of Mohawk River near Vischer Ferry power plant/Lock 7
The rocks here form part of the Vischer Ferry Zone of folded and faulted flysch (Figures 1 and 2). Thin-bedded greywackes and shales, with subvertical dip, are exposed in the discontinuous roadcut going down the paved road and branching off onto the dirt track down to the shore of the river. At the shore, similar thin-bedded flysch and shale comprises the outcrop extending west from the path to the abutment of the power plant (Figure 3). This outcrop displays asymmetrical folds and small faults connected with east-over-west thrusting. A detailed description of this outcrop appears in Bosworth (1989), who pointed out the incipient development of a melange-type fabric in the fault zone (Figure 3), mainly through fracture development and incremental slip on the fracture surfaces. Farther down the dirt track to the south-east, a small hillock and its shoreline on the river under the power transmission line exposes more subvertical, west-younging thin to medium-bedded greywackes and shales.
While the strata here are in part shale-dominated, enough arenaceous greywacke occurs here and in the surrounding areas for the Vischer Ferry Zone to be mapped as Austin Glen Formation across the Mohawk River. To the north, however, near Round Lake (Figure 2), the Zone changes to largely shale, lacking significant arenaceous wackes, and there it is specified to consist of Stillwater Shale. This change is gradational, and thinning and fining of the arenaceous component of the flysch is occurring, within the Zone, across the Mohawk River; we choose for consistency to include anything containing arenaceous greywackes within the Austin Glen Formation.

STOP 3. Thick-bedded Austin Glen Formation flysch
Thick-bedded Austin Glen Formation flysch of Halfmoon Greywacke Zone, folded, with melange on small thrust fault- road cut on north side of Route 146 east of Clifton Park
This outcrop (Figure 4) mostly exposes structurally intact medium to thick-bedded greywackes and lesser shales in a broadly antiformal structure, hence the popular name for this locality, Clifton Park Anticline. However, in the center of the outcrop there is a thrust fault, which can be identified from the zone of overturned steeply-dipping thinner greywackes and shales that form the lower limb of a close fold in the immediate hanging wall of the fault.
This fold might be a tightened hanging wall ramp anticline. To the west [structurally below] this fold structure, there is an approximately 3 meter wide zone consisting of broken blocks of greywacke in a disrupted shale matrix, which is melange derived from the adjacent materials, and defines the fault zone. We think that this fault is an excellent example that shows in miniature how the larger zones of melange formed.
This outcrop is part of a large structural slice, which we term Halfmoon Greywacke Zone (HGZ), that consists of relatively intact, medium-thick bedded greywackes like these, surrounded both to east and west by highly disrupted melange, including some materials exotic to the immediate greywacke-shale association. This HGZ slice consists along the Mohawk River of a disrupted large-scale synform; however we do not favor the klippen interpretation shown for it on the New York State Geological Survey maps since 1970; in particular there is no evidence for a westerly dipping, nor a relatively west-downthrown fault/fault zone on its eastern side.
Excellent sedimentary structure assemblages may be seen in the greywackes in this outcrop indicating deposition by turbidity currents, and local reworking by bottom currents [beds completely occupied by climbing cross-laminations], perhaps the tails of turbidity current events. Claims of the existence of shallow water sedimentary structures, particularly mudcracks, have occasionally been made for the Schenectady Formation, and for greywackes of the same structural slice as this outcrop near the Mohawk river (Rickard and Fisher, 1973); we think that these reports are mistaken, and the structures are probably either syneresis cracks, or tectonic structural features. All greywacke-bearing outcrops we have seen in the Hudson Valley and in the Schenectady Formation have turbidite characteristics, certainly deposited below wave base, and likely in substantially deep marine water given the analogy with modern arc-passive margin collisions, such as Timor-Australia.

STOP 4. Cohoes Melange outcrop
Cohoes Melange outcrop [eastern Mohawk River Central Melange Zone], cliff on Waterford side of Mohawk River below Cohoes Falls
This outcrop and its continuation up and downstream constitutes the best, and most continuous section through the melange of the Hudson Valley. Structural features seen here, and elsewhere in this belt indicate a "hard-rock" origin for the melange, particularly the striations visible on many of the characteristic "phacoidal" or lenticular splinters of the shale, and the polished nature of these surfaces in places when freshly exposed. Clear evidence of olistostromal origin of units with blocks in matrix is found in a few places, but the large majority of the melange in the region does not show features that require a surficial mass-wasting origin. As long as shear strains were high, imbrication and mixing of materials could be achieved in large ductile thrust fault zones, as long as some of these were out-of-sequence thrusts, in order to introduce originally overthrust materials [from the Taconic Allochthon] among the medial Ordovician flysch-derived melange matrix. The latest structures here and elsewhere in the melanges consist of quartz veins, some fibrous, and slickensided, which in many places, including here, show a consistent 120° plunge; this orientation is known to be associated with the Champlain Thrust in Vermont, which is an along-strike continuation of the faults defined by the Hudson Valley melange zones. This fault displacement direction contrasts with the ∼090° plunge of thrust-related slickensides in the Devonian Helderberg Group to the south between Ravena and Catskill.
The section here consists (Figure 5) of alternating zones of exotic-containing and less- to non-exotic- bearing melange. A large isolated wacke block is seen part-way down the cliff path; lower down, several large carbonate breccia blocks are exposed, possibly derived from a Taconic Allochthon source, or from normal fault scarps in the outer trench slope prior to arrival of thrusting and melange formation. Just east of the bottom of the path is a large block of black argillite, which is in our opinion derived from the allochthonous strata of the Taconic Allochthon, specifically from the upper Mt. Merino-basal Pawlet Fm. interval, which contains, regionally, black graptolitic argillites with Nemagraptus gracilis faunas like the one collected and identified by Riva [pers. comm., 1981] from this block. Smaller blocks of chert, also originally from the Mt. Merino Fm. of the Taconic Allochthon, occur at the base of, and above Cohoes Falls. The remaining materials in this part of the section consist dominantly of greywacke and shale [flysch], although there is also a persistent occurrence of greenish shale seams and films in all areas where the exotic melange occurs, as well as scattered small blocks of sideritic mudstone whose stratigraphic source is unidentified, and both of which are not seen in areas just containing greywacke and shale and their melange derivatives. Farther east in this outcrop than the black argillites, there are a few occurrences of blocks/lenses of a fossiliferous wacke, very similar to that exposed in a partly-disrupted bedded section at Snake Hill on Saratoga Lake.
This brachiopod/trilobite fauna contains Cryptolithus tesselatus [Riva, pers. comm, 1981]. Because of its local occurrence, we suggest that this lithology represents input to the flysch trough from a local across-axis source, unlike the majority of the flysch, which clearly has a southerly derivation and along axis transport, from the paleocurrent evidence.
If the water level is very low, excellent exposures of incipiently to strongly disrupted shales and silty wackes of the Waterford Flysch Zone may be seen just below the dam located east of the Waterford-Cohoes road bridge; these represent a discontinuous belt of in part less-deformed rocks forming a slice, or set of imbricate slices, on the eastern margin of the Mohawk River Central Melange. Access to this outcrop, at low water, may be obtained from either the north or south side of the Mohawk River, east of the bridge.

STOP 5. Poestenkill Gorge
Taconic Frontal Fault and Troy Frontal Melange Zone
This is one of the few exposures, and certainly the best (Figure 6), of the Taconic Frontal Fault anywhere along its ∼200 km length. Green arenites and silty wackes and slates of the Bomoseen Formation are in fault contact here with greywacke block-rich grey shale melange of the Troy Frontal Melange Zone. The original (presumed thrust) fault contact has been cut and displaced by a later steep strike-slip fault at this locality, so that most of the exposed length is of the latter; the thrust may be seen under and to the south of the waterfall. It dips quite steeply [∼55°], as is also the case at the few other exposures of this fault; a possible reason for this includes [back] rotation by later thrust ramps. It is the case that outcrop evidence of thrust sense of shear for this fault, here and at the few other localities where it is exposed, is not overwhelmingly convincing. An alternative explanation for the steep dip, also lacking convincing outcrop evidence, is that the fault is extensional, or has a component of late normal displacement, and formed late in, or long after, the Taconic orogenic event. Even if extensional, this in no way contradicts the regional relationships demonstrating the overthrust origin for the Taconic Allochthon and the belt of melange and deformed flysch.

STOP 6a - Troy Frontal Melange Zone
This cut (for location, Figure 7) exposes in all the north side and most of its length on the south side a similar greywacke block-rich shale matrix melange as seen at stop 5, the Troy Frontal Melange Zone. The exposure lies a few hundred meters west of the [here unexposed] trace of the Taconic Frontal Fault. It is close to a unique locality first investigated by Ruedemann (1901 b), the carbonate conglomerate of Rysedorph Hill [see below, Stop 6b] which is the main reason for stopping here in addition to stop 5.
Within the greywacke-shale melange here, late quartz veins like those seen earlier cut all other structures. One block of wacke about 20 meters from the east end of the cut on the north side shows a slate with cleavage oblique to bedding on part of one margin, and this cleavage is clearly cut by the lenticular phacoidal melange matrix fabric. Some of the wacke blocks in this cut have angular, fracture-controlled margins, others have a more rounded and smoothed appearance, possibly indicating they were not fully consolidated upon incorporation. The westernmost outcrop along the south side of Rt. 151 here shows a quite different assemblage, with both dark grey/black and green shale melange matrix, and only modest-sized [∼10-40 cm] sideritic mudstone blocks; it is identical to parts of the exposure in Cohoes Gorge, seen at stop 4. The contact with the greywacke block-rich melange to the east is not exposed, but is inferred to be a significant fault. This melange type forms the matrix on the west side of the exposure of the Rysedorph Hill conglomerate, located a few hundred meters to the north.

STOP 6b. Rysedorph Hill Conglomerate.
ASK PERMISSION at the house on the west side of Olcutt Lane BEFORE entering this property. Please DO NOT hammer this outcrop.
A limestone conglomerate, from which Ruedemann obtained a fauna ranging in age from the Cambrian through the medial Ordovician, forms a unique exposure on part of this hill. Walk up the slope within the woods from the unsurfaced Olcutt Lane, starting before the first bend to the east (Figure 7). Dark and green shale melange with small sideritic mudstone blocks is found, mostly as loose shale chips and fragments, on the slope. The limestone conglomerate and breccia is found forming a knoll, and also as loose fragments, near the top of the first slope. Much written about this famous [notorious?] locality presumes it to be in stratigraphic arrangement with the surrounding shales and greywackes. As you have seen from the roadcut, this is an untenable hypothesis, and the conglomerate/breccia must form a large block, in the exotic matrix melange, or on the contact of this melange with the block-rich greywacke melange to the east. Nonetheless, the large age range of the fauna in this small occurrence of limestone conglomerate needs explanation, even though it is now contained in a block within melange. We suggest that the limestone conglomerate/breccia may be explained by talus accumulation below a normal fault scarp produced by flexural extension in the outer trench slope of the Taconic foredeep basin [Bradley and Kidd, 1991], and the subsequent picking up of a sample of this breccia into the advancing accretionary thrust wedge bordering the Taconic Allochthon. Strata containing physically similar carbonate conglomerates/breccias do occur within the intact stratigraphic sequence in the Taconic Allochthon, but they nowhere have extended faunal age ranges, and none are known with ages younger than early Ordovician.
2016: GE images from 2015 suggest that this outcrop may have been removed.

STOP 7, Ruedemann's "type" section
Outcrops of melange and flysch in old railroad cut and bed of Normanskill [Ruedemann's "type" section]
These outcrops form the "type locality" of Ruedemann for the "Normanskill Formation", mainly because of the fauna he obtained here at Kenwood, and "nearby", including Stop 8 at South Glenmont. As you can see, structural disruption is prominent, and the bedded sections seen between faults have no defined, or definable, top or base. In addition, the use and abuse of the term Normanskill since Ruedemann, especially as a time-stratigraphic term, makes it inappropriate to use it for the general lithic assemblage of flysch greywacke and shale, which is, despite the structural disruption, quite well exposed here. In the creek bed, if the water level is not too high, a downward-younging bed in the crest of an antiform may be seen (Figure 8), with the turbidite sole structures exposed on a surface defining the fold hinge. This structural complexity is unusual for the bedded greywacke-shale sections in the Hudson Valley; Vollmer suggested that the stratigraphic inversion represented by the downward-facing nature of this fold may have been produced by slumping, with the fold being the regional set later superimposed on the already inverted section. This outcrop maps near the eastern margin of the Mohawk River Central Melange Zone (Figure 2).

STOP 8. South Glenmont locality of allochthonous Mt. Merino Cherts
Outcrop in road cut, by road and to east of bridge up to power line, [and along railroad tracks].
Black, grey, and green cherts, some with burrow mottling, as seen in this set of exposures, are characteristic small and large blocks in the exotic melanges. However, they are always blocks, or fault bounded slices, in this context. Identical chert lithologies are found in stratigraphic sequence with other rock types only within the Taconic Allochthon. There they occur only at one position in the stratigraphic succession, at the top of varied continental rise-deposited sediments derived from the Cambro-Ordovician passive margin of North America, and immediately below black graptolitic shales with N. gracilis graptolite faunas, which are in turn overlain by greywacke-shale turbidites of the Pawlet Formation. This locality yielded to Ruedemann the most abundant fauna found in the greywacke-shale area of the "Normanskill", and has as a result strongly influenced the presumed age of the flysch of the Hudson Valley. We are of the opinion that all occurrences of these cherts are highly allochthonous, representing tectonically separated, and perhaps erosionally isolated, pieces originally emplaced as integral parts of the Taconic Allochthon. We think that all ages derived from the faunas in the cherts, and the related black graptolitic slates, are therefore older, by at least some small amount, than any of the greywacke-shale flysch of the Hudson Valley. Prominent down-dip plunging folds (Figure 9) are seen in several parts of this set of outcrops; these probably represent rotation of originally shallow-plunging folds by heterogeneous simple shear associated with thrusting, as indicated by Vollmer and Bosworth (1984) for the more strongly deformed flysch and melange generally. This locality maps close to the eastern boundary of the Mohawk River Central Melange Zone (Figure 1).

STOP 9. Normanskill melange and broken formation.
This outcrop in the north bank of the Normanskill exposes shaly rocks with greywackes that can be demonstrated to be in part a broken formation (Figure 10), with partly traceable sedimentary layering , rather than a melange with completely disrupted layering. Additionally, this locality contains some folded quartz veins. The outcrop also maps within the Central Melange Zone.

STOP 10 - Feuri Spruyt and Callanan Quarry
Unconformity with Helderberg Limestones overlying melange. PERMISSION REQUIRED- request permission in advance by calling 518-767-2222, or writing Callanan Industries Inc, Corporate Headquarters, South Street, South Bethlehem, NY 12161
This locality (Figure 11) shows carbonates of the basal Helderberg Group [early Devonian] unconformably overlying the folded greywackes and shales, and melange of the Ordovician.The boundary between the Ravena Greywacke Zone and the eastern side of the Mohawk River Central Melange Zone passes beneath the unconformity just west of the quarry (Figures 1, and 11). In particular, the unconformable relation to the melange demonstrates that the fault zone which created the melange is an Ordovician structure, and predates entirely, at this position, the Acadian structures that fold the overlying Devonian strata south of this place (Bosworth and Vollmer, 1981). The map relationships, and unfaulted structural condition of the Helderberg Group, west of this locality, shows that all the width of the melange belt comprising the western and eastern exotic melange, which goes beneath this unconformity, must also be an Ordovician, and Taconic-age structure.

A5:GEOMORPHOLOGY, PALEOCLIMATOLOGY AND LAND USE CONSIDERATIONS OF A GLACIATED KARST TERRAIN; ALBANY COUNTY, NEW YORK
Paul A. Rubin
909 County Rt. 2
Accord, NY 12404
Thorn Engel
7D West St.
Voorheesville, NY 12186
Michael Nardacci
Point of Woods
19 Briarwood Terrace
Karstified terrains in Albany County, New York provide evidence of paleoclimatic conditions during Pleistocene glaciation. Caves and the areas surrounding them preserve important clues that can be interpreted to reconstruct portions of the geomorphic and paleoclimatic history of a region. Knowledge gained from these investigations is of increasing importance as development pressures extend into these forested, agricultural and rural areas. This paper focuses on the geology, karst hydrology, and glacial features of two areas not previously described. As a result of karst processes and anthropogenic diversion of the headwaters of the Onesquethaw Creek, the Hollyhock carbonate aquifer and its receiving stream (i.e., Onesquethaw Creek) are extremely sensitive to contaminant inputs. Thus, we have incorporated a section specific to land use considerations and concerns. This ongoing work is an extension of previous work addressing the interaction between karst and glaciation (Rubin, 1991 b; Palmer et al., 1991a, 1991b).
Two karst areas will be visited on this field trip. The first stop, at the Hollyhock Hollow Sanctuary, will feature a cave system that 1) developed prior to the advance of the late Wisconsinan (Woodfordian) Laurentide ice sheet; 2) was enlarged by meltwater invasion; and 3) remains active today. The second stop will be at Joralemon Park, where active and relict caves are used to interpret the interaction between caves and glacial processes. Solutionally enlarged fractures and relict caves and swallow holes in the groundwater basin are integral, functioning components of the epikarst, funneling runoff and infiltrating meteoric waters to deeper conduit flow routes.

GEOMORPHOLOGY, PALEOCLIMATOLOGY AND LAND USE CONSIDERATIONS OF A GLACIATED KARST TERRAIN; ALBANY COUNTY, NEW YORK

Cross Vlomankill

Exposure of Snake Hill shale behind house on right.

Feura Bush Quarry uphill and on right.

Roadcut through Coeymans Limestone.

STOP 1. HOLLYHOCK HOLLOW SANCTUARY
The Hollyhock Hollow Sanctuary and surrounding area represent a unique geologic and hydrologic setting. The Hollyhock carbonate aquifer supports no surface drainage today, except for the Onesquethaw Creek which is seasonally pirated underground for ∼1 km (0.7 mi). All drainage is subsurface in limestone bedding planes, joints, faults and conduits, largely within the Manlius and Coeymans Limestones. Structural deformation here within the Hudson Valley Fold Thrust belt has folded and faulted these limestone units. This deformation is locally responsible for orienting subsurface flow paths and was in place prior to Wisconsinan glaciations. During glaciation, subglacial meltwater carved shallow bedrock channels in the Coeymans Limestone. Several relict caves and perhaps the only known meltwater-carved limestone pedestals in such a setting attest to the unique geology of this karst basin. Scallops (solutional pockmarks in cave walls) in swallow holes document former rapid surface and groundwater flow here. Some of this meltwater was pirated into now relict swallow holes over many thousands of years. This same flow created or enlarged limestone cave conduits which today still drain the carbonate groundwater basin that extends to the north and northwest. These enlarged joints and conduits provide a route for possible rapid transport of contaminants.
Location stops for this field trip are organized sequentially for walking tours.

Cross the Onesquethaw Creek.

Cross Feuri Spruyt Creek

Esopus Shale outcrop on right side of road.

Large rock of Onondaga Limestone on right.

Joralemon Park tennis courts on right.

STOP 2. JORALEMON PARK
At Joralemon Park and vicinity, entrances to active (Hannacroix Maze and Merritt's Cave) and relict (Joralemon's) caves will be visited. Damming of a former surface drainage route by glacial sediment, as well as erosional derangement of surface streams, have resulted in the enlargement of the Hannacroix Maze floodwater cave. All surface flow from throughout the basin is deranged from an earlier flow route and is now pirated through Hannacroix Maze. Prior to deposition of the sediment dam that now forces surface water from throughout the basin to be pirated through Hannacroix Maze, surface flow occurred through Joralemon's Cave. Nardacci (1994) has documented much of the karst hydrology of this stop.

A6:FLYSCH AND MOLASSE OF THE CLASSICAL TACONIC AND ACADIAN
OROGENIES: MODELS FOR SUBSURFACE RESERVOIR SETTINGS
GERALD M. FRIEDMAN
Brooklyn College and Graduate School of the City University of NY
Brooklyn, NY 11210
Northeastern Science Foundation affiliated with Brooklyn College, CUNY,
This field trip will examine classical sections of the Appalachians including Cambro-Ordovician basin-margin and basin-slope facies (flysch) of the Taconics and braided and meandering stream deposits (molasse) of the Catskills. The deepwater settings are part of the Taconic sequence. These rocks include massive sandstones of excellent reservoir quality that serve as models for oil and gas exploration. With their feet, participants may straddle the classical Logan's (or Emmon 's) line thrust plane. The stream deposits are Middle to Upper Devonian rocks of the Catskill Mountains which resulted from the Acadian Orogeny, where the world's oldest and largest freshwater clams can be found in the world's oldest back-swamp fluvial facies. These fluvial deposits make excellent models for comparable subsurface reservoir settings.
This trip will be in two parts: (1) a field study of deep-water facies (flysch) of the Taconics, and (2) a field study of braided- and meandering-stream deposits (molasse) of the Catskills. The rocks of the Taconics have been debated for more than 150 years and need to be explained in detail before the field stops make sense to the uninitiated. Therefore several pages of background on these deposits precede the itinerary. The Catskills, however, do not need this kind of orientation, hence after the Taconics (flysch) itinerary, the field stops for the Catskills follow immediately without an insertion of background information.

A6:FLYSCH AND MOLASSE OF THE CLASSICAL TACONIC AND ACADIAN
OROGENIES: MODELS FOR SUBSURFACE RESERVOIR SETTINGS

Rensselaer Center of Applied Geology
We shall stop at the Rensselaer Center of Applied Geology, headquarters of the Northeastern Science Foundation affiliated with Brooklyn College of the City University of New York, for a brief review of the geology.

STOP 1. R.P.I. , '87 Gym
Exposure behind fence adjacent to gym.
Ruedemann (1930, p. 114; also Fig. 64) described and photographed this exposure as a good example of a "cliff of mylonite," one of the "excellent exposures of a fault breccia" on the campus of Rensselaer Polytechnic Institute. According to Ruedemann and reconfirmed by Elam (1960) a thrust fault follows part of this street (Sage Ave.) and Ruedemann mistook this conglomerate for a fault breccia. Perhaps the presence of criss-crossing veins in this exposure led to his interpretation of a "cliff of mylonite." Jack G. Elam (1960; unpublished Ph.D. thesis at Rensselaer Polytechnic Institute) assigned the rocks at this exposure to the Schodack lithofacies of Early Cambrian age. Cushing and Ruedemann (1914) had introduced the "Schodack Formation". Zen (1964) has renamed this formation the West Castleton Formation. As already explained, this formation is now assigned to the Hatch Hill Formation (Fig. 1).
Lowman (1961) recognized that the boulders are a conglomerate and not a breccia, and following Kuenen and Migliorini (1950), he introduced the term brecciolas for these rocks.
The limestone, sandstone, and chert boulders which are embedded in shales at this exposure range from angular to rounded and show considerable variation in size (Fig. 9). Some boulders are coarse-grained fossiliferous limestone fragments with a micritic dolomite matrix. The rocks above the brecciolas are greenish-gray shale.

STOP 2. TROY HIGH SCHOOL QUARRY
Walk to the running track and on track proceed left (north) to exposure below RPI housing units.
The spectacular brecciolas at this exposure consist of three members with eleven sub-members (Lowman, 1961); some of the deposits that Lowman studied have since been destroyed. For details of the rocks, refer to Lowman's descriptions (1961). The brecciolas are lithofacies of the Hatch Hill Formation, as at Stop 1.
A thin-section study shows the limestone clasts to consist of biomicrites, biointramicrites, and micrites with varying terrigenous quartz and clay-minerals. The intraclasts are of pelmicrite. Shell fragments have been selectively dolomitized. The carbonate sediments must have lithified before their displacement downslope.
The brecciola bed is steeply dipping (80°) and is approximately 3 m thick. It is interbedded within a fissile shale. The basal contact of the bed is at the top of the exposure, and the top of the bed is at the base of the exposure. The matrix between the clasts ranges from sand at the base of the bed (top of the exposure) to clay at top of the bed (base of the exposure). This change in the texture of the matrix is typical graded bedding.
Although some clasts are rounded, most of them are angular and slab-shaped (Fig. 10). Some slabs experienced multiple bending reflecting high-energy impact (Fig. 10). Sporadic slabs 0.5 m to 1 m long appear to have been in the process of breaking up, with clay wedged into the fractures of the separating clasts. The clasts are sub-parallel to the boundaries of the bed.

STOP 3. RUSHOR'S QUARRY, TROY
Walk old wagon road uphill to ruins of former buildings (now only the floor of the buildings is preserved), site of former abandoned quarry. Look at exposure in old quarry (Rushor's Quarry)
The rocks at this exposure are part of the Austin Glen Member of the Normanskill Formation of Middle Ordovician age. In contrast to the Cambrian (Hatch Hill Formation) deep-water rocks which were tectonically emplaced in the Troy area, the Normanskill Deep-water suite formed in situ after deep submergence of the Cambrian-Early Ordovician carbonate shelf. The sediment composing the rocks at this site were derived from what is now east (Fig. 3), but was north during the Paleozoic. At this stop we see basin-margin sediments devoid of brecciolas. The clue to the presence of a paleoslope are sole marks on the undersides of sandstone beds (Fig. 14). These marks are infillings (molds) of depressions that formed in the soft bottom clays (now shales) as particles in turbidity current flows or sand falls scoured or gouged the bottom. They are also known as impact marks or tool marks. The following sole marks can be seen (definitions modified from Pettijohn and Potter, 1964): flute molds - a raised sub-conical structure, the up current end of which is rounded or bulbous, the other end flaring out and merging with the bedding plane; groove molds - rounded or sharp-crested rectilinear ridges produced by filling of grooves; brush marks - essentially a bounce cast with a crescentic depression on the down-current end; prod molds - a short ridge, parallel to the current, which unlike flute molds, rises down-current, and ends abruptly; frondescent marks -a type of load-flow structure that covers some soles with crowded lobate molds overlapping in the down-current direction.
The rocks in this quarry consist of interbedded sandstone and shale (Fig.l5) which show the characteristics of distal turbidites (Walker, 1967): cross laminae, convoluted laminae, sole marks, graded beds, parallel sides and regular beds, thin beds, fine grain size; individual sandstone beds rarely amalgamate.
The exposure in this quarry is that of a typical flysch composed of alternating sandstones and shales (Fig. 15 ). Most sandstone beds are composed of two units: an underlying finely laminated sandstone and an overlying ripple cross-laminated sandstone (Figs. 16, 17). The ripple cross-laminated sandstone may scour into the underlying finely laminated sandstone. These two sandstone units correspond to the B and C units of a Bouma sequence; the shale would be a Bouma E unit. Please look carefully at the two sandstone units, keep a mental image of their appearance, and carry this image to the next stop where you will need it for interpreting the geological history.

STOP 4. RYSEDORPH HILL
This roadcut is on the southern flanks of an unnamed peak of Rysedorph Hill which is topographically part of a ridge composed of two hills (Rysedorph Hill and Olcott Hill)(Fig. 18). At and near the peak of Rysedorph Hill Ruedemann (1930) discovered spectacular conglomerates and faunas which are now obscured by vegetation; only small sporadic blocks or pebbles of limestone are now found dispersed in shale. This spectacular deposit is known as Rysedorph Hill Conglomerate and, as Ruedemann described, consisted for the most part of limestone conglomerate (see Sanders, 1995).
The rocks at this roadcut are quite different from those which Ruedemann described. Large and small blocks of sandstone and carbonate rock are set in a dark-colored deep-water shale. One of the blocks on the east side of the road is of particular interest. This block consists of Austin Glen/Normanskill sandstone lithology. In fact, it reveals the typical two kinds of sandstone units that we have seen at STOP 3 (Rushor's Quarry in Troy): an underlying finely laminated sandstone and overlying ripple cross-laminated sandstone which correspond to the B and C units of a Bouma sequence (Fig.19). One wonders how this one block traveled from Rushor's Quarry in Troy to this site!
The kind of lithology exposed at this stop has been designated wildflysch, a term applied to a spectacular deposit consisting of small- to enormous blocks of sedimentary, igneous, and metamorphic rocks set in a matrix of fine-grained, typically dark-colored marine shale, siltstone, or mudstone (Fig.12). In modern terms, we would designate the wildflysch as one kind of diamictite (Friedman et al., 1992).
Study of sandstone blocks show them to be fine- to medium-grained and for the most part composed of quartz. Authigenic quartz overgrowth is in places so intense that the original texture is obscured. Plagioclase feldspar and microcline are common. They are commonly sericitized and calcitized. Fragments of sedimentary, igneous, and metamorphic rock are abundant, especially those of sedimentary rocks. Particles of carbonate rock include micrite, oolitic and pseudo-oolitic limestone, peloidal limestone, dolomitic limestone, and crinoidal limestone. These fragments of carbonate rock contain authigenic feldspars which are diagnostic of pre-Knox unconformity (Beekmantown or Sauk) deposits (Buyce and Friedman, 1975 ). Other kinds of rock fragments are composed of siltstones and shales, especially bituminous shales. Metamorphic rock fragments are those of sericite-chlorite schists and quartzites. Igneous rock fragments have porphyritic-ophitic texture. Finely crystallized rock-fragment particles are those of recrystallized volcanic glasses or volcanic rocks, and contain chalcedony and chlorite.
Table 1 shows the petrographic composition of the sandstone blocks. They do not qualify to be called graywacke, despite such usage for these rocks in the literature (Potter, 1979). According to the classification of Friedman et al. (1992) the sandstones are classified as quartz-feldspar-rock fragment sandstones.
Carbonate blocks are for the most part composed of dolostone. The provenance of these blocks includes Cambro-Lower Ordovician platform carbonates (oolitic and peloidal carbonates and authigenic feldspar) and deep-water Austin Glen/Normanskill sandstone. Hence these conglomerates are younger than Normanskill which would make them Upper Ordovician Snake Hill Formation which is the only Ordovician unit younger than Normanskill present in New York (Fig. 1b)(Fisher, 1977). Because of age uncertainties I prefer to label these rocks Tippecanoe-correlative conglomerates and call them Rensselaer Conglomerate since they occur in the town and county of Rensselaer.
To recycle deep-water Austin Glen/Normanskill deposits an initial uplift is necessary. As Sanders (1995) points out "because eastern New York is part of the Appalachian orogenic belt ... 'uplift' means thrust faults". This mechanism displaced deep-water Normanskill deposits into a setting of shallow water or emergence from which erosion detached the blocks and recycled them downslope, once again into deep water. This view is at variance with that of those who feel that these conglomerates resulted from tectonic emplacement (Potter, 1979). However, these deposits are incoherent subaqueous slumps (debris flow) of deep-water setting which were part of a slumped mass that moved by gravity downslope (Friedman et al., 1992, p.). Some of the boulders form a nearly perfect sphere (Fig.12) implying erosional rather than tectonic forces. The blocks are related to erosion on the front of the thrusts which contained rocks from each of the three sequences: Taconic, Sauk, and Tippecanoe (Normanskill) (see Fig. 1a). The presence of Sauk material indicates that some thrusts broke loose inboard of the former shelf edge and transported the carbonate-sequence material over the foreland-basin shales of the Tippecanoe Sequence (see also Sanders, 1995; DeAngelis, 1995).

STOP 5. POESTENKILL FALLS AND GORGE
We are back in Troy from where we initially set out; in fact we passed this site on our way between stops 2 and 3. You may ask why has a visit to this remarkable site been postponed till now, and why did we have to backtrack this circuitous route between Rysedorph Hill and Poestenkill Falls? The answer is that the experience of Rushor's Quarry (Stop 3) and Rysedorph Hill (Stop 4) is essential to an understanding of the geology of Poestenkill Falls and Gorge.
At this classical site Ruedemann (1930) shows "Logan's Line" (now known as Emmons' Line; Rodgers, 1970), the thrust plane which places Cambrian over Ordovician rocks surfacing at this site. Elam (1960) concurs and places Lower Cambrian rocks (his Poesten lithofacies, later West Castleton Formation; Zen, 1961) in contact with Middle Ordovician rocks (the Austin Glen Member of the Normanskill Formation). As already explained, the Cambrian strata, a typical flysch, have now been assigned to the Hatch Hill Formation (Fig. 1a). The Ordovician rocks are wildflysch, as at Rysedorph Hill, and hence I prefer to label them Tippecanoe-correlative strata and call them Rensselaer conglomerate (Hatch Hill Formation) as at Rysedorph Hill. As at Rysedorph Hill, the boulders and blocks consist of sandstones, shales, and limestones (Fig 20). Among the sandstones, blocks of Normanskill rocks can be identified. At this site Cambrian flysch has been thrust over Ordovician wildflysch. In places interbedded with the Ordovician wildflysch are strata of bedded flysch of Normanskill lithology which remind us of Rushor's quarry. Hence although consisting for the most part of debris-flow deposits the Ordovician strata are in part of turbidite origin.
This overthrust (Fig. 21) is interpreted as a segment that extends from Canada through Vermont, New York, and farther south. The fault line is well exposed in the south wall of Poestenkill Gorge. Cambrian shales occur above (east of) the fault, and Ordovician strata below (west of) the fault The Ordovician strata have been described as a fault breccia or mylonite in which blocks of large size have been incorporated in shaly matrix. The matrix shows an anastomosing cleavage pattern that does not penetrate the boulders and blocks. Although described as a fault breccia or mylonite (Ruedemann, 1930; Elam, 1960) this rock is a wildflysch. The blocks are interpreted as having moved down a steep slope from near a shelf edge to a basin or basin margin.
The Ordovician rocks are highly tectonized, especially towards the thrust. Antithetic post-thrust faulting is noted on the north side of the thrust sheet with an approximately 2m displacement seen on the steep slope above the thrust. At and below the thrust sheet in the south wall of Poestenkill Gorge a dense black material may be pseudotachylite, a rock produced in the compression and shear related to intense fault movement, involving extreme mylonitization. My own professor Dr. S. James Shand introduced this term (Shand, 1916) for mylonites he encountered in the Orange Free State of South Africa. As Shand (1947) points out, this kind of "mylonites ... proved most puzzling to field geologists meeting them for the first time".
The Cambrian rocks contain abundant black particles which may be phosphatic.
During the Industrial Revolution numerous factories, clustered on the north slope of Poestenkill Gorge, were making cotton cloth, and curry combs, barbed wire, and buckwheat flour machines, and much more. The first mills were developed in the lower section of the gorge as early as 1791. Their full potential was realized when Benjamin Marshall constructed a brick cotton mill on the north side. Water power began its decline with the popularity of steam power at the turn of the century. Today obscure, moldering industrial ruins testify to this former busy activity. The last of the abandoned mill buildings tumbled into the stream in the fierce flood of 1938.

STOP 6. OLISTOLITHS
At this site "exotic" boulders of various kinds are scattered through shale. Of these one large well-rounded boulder of white limestone demands particular attention (Fig. 22). Smaller angular blocks include those of sandstone and limestone. These olistoliths recall those of Rysedorph Hill and Poestenkill Falls and Gorge and are considered Tippecanoe correlative Snake Hill Formation which at the other two sites have been designated Rensselaer Conglomerate and deserve the same label here. Fisher (1977) applied the term Poughkeepsie Melange to this deposit. However, for a deposit to be called a melange it should be incorporated within a unit "that was moving as an overthrust or as a gravity-gliding mass"(Friedman et al., 1992). The deposit at this site is composed of olistoliths and is not a melange, as Rowley and Kidd (1982) likewise observed.

STOP 7. EXPOSURES SOUTH OF SCHODACK LANDING
We shall first examine the road cut on the east side of the highway and then walk on dirt road across the railroad tracks to view mere fine exposures.
Figure 23 describes and illustrates the section seen. Note exposures of bedded micrite. Micrite is overlain by distinctive lenticular brecciolas. Many of the clasts in these conglomerates/brecciolas evidently were derived from the digging up and local transport of nodular bodies of carbonate that may have become segregated as isolated "nodules" during early marine diagenesis of these deep-water carbonates. The conglomerates form convex-up lenses up to 2 m thick and at least 10 m across. Their bases are flat surfaces or fillings of local channels cut a decimeter or so into the underlying nodular zone. Siltstone strata lacking carbonates drape over the convex-up lenses (Friedman and Sanders, 1995, in press).
These lenses are analogous to hummocky strata, which have been ascribed to combined effects on shelf sediments of waves and currents. The waves involved in the origin of these deep-water, off-shelf brecciolas probably were tsunami (see previous discussion).
At the top of the slope on the east side of the railroad track an exposure shows a graded layer (2 m thick) of shingled clasts that may have been dumped in a manner of hours (Fig.11 ). The comparable thicknesses of the overlying strata may have accumulated over thousands of years.

STOP 8. JUDSON POINT
Figure 24 illustrates the section seen at this stop and describes lithofacies. The section is dominated by massive coarse sandstone beds of excellent reservoir quality which display high porosity and excellent sorting. They are analogous to sandstones forming deep-water reservoirs in California and elsewhere. Those not knowing the regional geology may mistake them for high-energy shallow-water deposits. In places the beds contain micrite pebbles.

STOP 9. EXPOSURE ON EAST SIDE OF ROUTE 9
(across from a white house)(SECTION SOUTH OF HUDSON)
Figure 25 shows and describes the lithofacies exposed at this stop and located across from white house. Note especially the interesting interbeds of fine-grained limestone (micrite) and dark shale (Fig. 7) and the carbonate-clast conglomerate (Fig. 8). The cycles consist of alternating thin-bedded micrite and calcareous shale (Fig. 7). The thickness of the micrite beds is about 1 to 5 cm and that of the calcareous shale varies between 3 and 20 cm. Table 2 and figure 26 provide data on the mineralogic and isotopic compositions of the alternating beds of micrite and calcareous shale. The micrite is pure calcite and encloses particles of quartz. The calcareous shale is composed of clay minerals and feldspar particles; its carbonate concentration is about 10% (calcite, dolomite, siderite) (Table 2). The stable carbon isotopic composition of the carbonate of the two interbedded lithologies is almost identical; the oxygen isotopic composition reflects deep-burial diagenesis (Table 2). The carbon isotopic composition of the brecciola overlying the micrite-calcareous shale cycles is enriched in 13C. Although the range of carbon isotopic composition of total dissolved carbon in seawater is relatively narrow, a consistent decrease in ä13C occurs with depth of water (around 2.6 per mil) (Berger and Vincent, 1986). Thin-section study of the brecciola confirms its shallow-water origin: radial ooids, echinoderm fragments, and intraclasts of oolitic facies. An approximately 2.6 per mil increase in ä13C is shown by comparing the shallow-water brecciola facies with the deep-water micrite. The brecciola facies at this stop represents a shelf-edge facies that a tsunami broke loose and transported to great depth.
The strontium isotopic composition requires discussion (table 2). The principal sources of marine Sr with distinctive 87Sr/86Sr ratios are (1) old granitic basement rocks of the continental crust (high Rb/Sr, high 87Sr/86Sr); (2) young volcanic rocks (low Rb/Sr; low 87Sr/86Sr); and (3) marine carbonate rocks on the continents (low Rb/Sr, intermediate 87Sr/86Sr)(Faure, 1991, p.359). Because young volcanic rocks are not relevant in a discussion of the Lower Paleozoic, only granitic basement rocks and marine platform carbonates determine strontium isotopic composition. The 87Sr/86Sr compositions of the carbonate in micrite and calcareous shale (0.711110 and 0.715163) are higher than in Lower Paleozoic seawater (0.7090-0.7095)(Burke et al., 1982) (Fig. 27) and consistent with precipitation from waters containing significant proportions of continent-derived fluids enriched in 87Sr as a result of basement weathering or percolation through soils or sediment on the continental platform.
Weathering of Precambrian terrain causes enrichment of radiogenic 87Sr (87Sr/86Sr 0.716±0.004) within river and lake waters (Faure et al., 1963). Waters originating from a granitic continental source have a high 87Sr/86Sr ratio relative to those derived from a platform of marine carbonates (Fig. 27). Even though the 87Sr/86Sr composition of the carbonate in both the micrite and calcareous shale is higher than in Paleozoic sea water, the difference between the two compositions is remarkable. The strontium isotopic composition of the carbonate in the calcareous shale almost overlaps that of the granitic basement crust, whereas that of the micrite is much lower and closer to that of Paleozoic sea water (Fig. 27). What determines these drastic changes in isotopic composition of such closely interbedded units? The highly radiogenic isotopic ratios of the carbonate of the calcareous shale reflect supply of radiogenic strontium from the decomposition of the detrital particles, such as feldspar and clay minerals which are present in this rock. By contrast, because the calcite of the micrite is essentially devoid of such detrital particles, its strontium isotopic composition is closer to that of Lower Paleozoic seawater.
Because strontium isotopes are not subject to significant mass fractionation during precipitation (Faure, 1986), the waters responsible for precipitating the carbonate of the calcareous shale must have derived from a granitic continental source. The only such source would be the Precambrian shield which must have been exposed during Early Cambrian times. The 87Sr/86Sr ratio of the micrite, though much lower, still indicates enrichment of radiogenic strontium from the granitic continental terrain, but its signature is considerably closer to that of marine platform carbonates.
The strontium isotopic evidence indicates that the calcareous shales were derived from exposed granitic basement. Sea level must have been low so that weathering and erosion of the granitic continental terrain generated the fine-textured particles. Rivers then distributed the debris across the emergent continental platform and down the slope, probably through submarine canyons. As pointed out earlier, a large block of quartzite in this formation has been tentatively identified as derived from part of the wall of a submarine canyon (Friedman, 1972; Friedman Sanders and Manini, 1982). By contrast, the strontium isotopic evidence for the micrite suggests mixing of waters originating from granitic continental terrain with waters from the epeiric marine carbonate platform under conditions of high stand of sea level. Thus the calcareous shale beds represent low-stand sea-level facies tracts, whereas the micrites are high-stand sea-level facies tracts.
The alternating thin-bedded micrite and calcareous shale beds reflect rapid changes in sea level. To produce such closely interbedded lithologies, the sea level must have moved up and down like a piston. Such cycles have been explained as astronomical rhythms (de Boer, 1991). For low latitudes, the precession of the Earth's axis has been assumed the cause of such rhythms. Precession cycles last about 19,000 and 23,000 years. At this time no dates are available to determine the rate of sea-level changes, but 19,000 to 23,000 years are possible time frames for micrite-calcareous shale couplets to accumulate.

STOP 10. SOUTHWEST CORNER OF BECRAFT MOUNTAIN (Fig. 28)
At the base of this exposure rocks of the Mount Merino Formation of the Taconic Sequence (Fig. 1) consist of highly deformed cherty dolomite. A low-angle, irregular unconformity separates this Ordovician formation from the overlying Silurian Rondout Formation, a silty dolomite. The lower part of the Rondout Formation is undeformed, however, a bedding thrust through this formation has deformed the Rondout Formation above this thrust (Fig. 28). Undeformed, laminated, whitish limestones of the Manlius Formation overlie the Rondout Formation. Within the Manlius Formation a bedding thrust folded the upper part of this formation (Fig. 28).
X-ray study of the rock of the bedding thrust within the Manlius Formation shows it to consist of calcite (96%) and quartz (4%). Its isotopic signatures are in ä13CPDB +2.4, ä18OPDB -9.9, and 87Sr/86Sr 0.715096 (10) (&plsmn;2 S.D.) (The Sr analyses are normalized to 86Sr/88Sr = 0.11940. Analyses of NBS 987 averaged 0.710241 (09) (n = 39) during the period of these analyses. Errors on 87Sr/86Sr are given as 2 sigma (95 %) in the last two digits). The carbon and oxygen isotopes tag a hot heavy-carbon enriched fluid and the strontium isotopes a radiogenic strontium of composition close to that of the continental crust
The thrusts at this exposure are post-Taconic and resulted from Acadian or Alleghanian orogenesis.

Note Catskill front from distance as you approach bridge.

STOP 11. BRAIDED AND MEANDERING STREAM FACIES SEEN FROM A DISTANCE
From the vantage point of this stop we see to the west the classical fluvial sequence of the Middle and Upper Devonian rocks of the Catskill front. Note continuous ledges near the top of the front which reflect the presence of laterally continuous, coarse-grained sandstones and conglomerates deposited in braided streams (Buttner, 1968). Below the continuous ledges are discontinuous cliffs which reflect laterally interfingering channel sandstones and overbank shales deposited in meandering streams.
Infrared photography of the Catskill front from this stop brings out amazing details (Mutch, Head, and Saunders, 1968).

STOP 12. TRESTLE TO MOUNTAIN HOUSE
Walk approximately 300 feet uphill to first sandstone body.
Meandering-Stream Facies
This grayish green, medium-grained graywacke of the Hamilton Group of Middle Devonian age displays abundant truncations resulting from lateral cutting; the sandstones within the channels are crossbedded and display abundant reactivation surfaces. This channel complex is about 15 feet thick and is sandwiched between overbank shale which is well exposed in the hangover at the lower sandstone contact. Note sporadic pebbles, wood fragments, and wood casts as well as onlap and toplap. Looking uphill along the clearing of the old trestle to Mountain House between cliffs of similar sandstone bodies the slopes mark the sites of interbedded shale. The interbedded sandstones and shales represent interfingering channel and overbank deposits of meandering-stream facies. The lateral relationship between channel and overbank will be apparent at stop 15. The green color of the graywacke reflects the abundance of chlorite in the rocks. This chlorite was derived from the source terrain to the east which consisted of metamorphic rocks of the greenschist facies.
A similar sandstone body occurs about 300 feet below which is underlain by gray, red, and green shales.

STOP 13. TWILIGHT PARK
Twilight Park is a private residential section and permission is needed to park here which may be obtained from the Superintendent Hillard Hommel or Justine L. Hommel, Box 129. Haines Falls, NY 12436 (phone 518-589-6191).
The site at this bridge was one of the preferred views of the Hudson River School of Landscape Paintings. Asher Durand (1786-1886) in his painting Kindred Spirits illustrated this site, including the crossbedding developed within the point bars of the meandering stream facies visible below this bridge (Jordan, 1995).

STOP 14. BRAIDED-STREAM FACIES, HUNTER
At this site polymictic conglomerate of braided-stream facies overlies sandstone of meandering-stream facies (Friedman, Sanders, and Kopaska-Merkel, Fig. 4-17). Small channels of conglomerate also cut through sandstone. The pebbles in this conglomerate range in diameter between 3 and 10 cm. The pebbles and sand particles are composed of quartz, including vein quartz, and various sedimentary and metamorphic rock fragments.
Streams of high energy must have been at work to transport these large pebbles. As we have seen from stop 11 these streams were laterally continuous channel complexes devoid of intervening overbank deposits. The coarse particle size of the conglomerates and the absence of overbank shales or siltstones suggest a braided-stream deposit This complex stream system developed on a slope of steep gradient, most probably in association with a series of coalescing alluvial fans that spread westward from the high, tectonically active source terrain to the east

STOP 15: MEANDERING-STREAM POINT-BAR FACIES
MEANDERING-STREAM POINT-BAR FACIES: CHANNELS, OVERBANK, AND SWAMP
This exposure shows a point-bar sequence in Tully-clastic correlative strata of the Gilboa Formation (Upper Givetian, Uppermost Middle Devonian). Two channels are exposed in this road cut, a lower channel and an upper channel (Fig. 29). The lower channel truncates overbank siltstone, whereas the upper channel truncates the lower channel and laterally adjacent overbank siltstone. A shale-pebble conglomerate, as a lag concentrate, overlies the truncation surface of the lower channel; in part this conglomerate is now hidden by fallen debris. This point-bar sequence at this site represents an abandoned meander which became an oxbow lake.
In rocks of the overbank facies, dark gray to black interbeds and lenses containing abundant coarse plant remains, consisting of what appear to be stems and branches primarily, and locally developed coaly material, represent a back-swamp environment located on the slip- off slope side of the lower channel. The back-swamp facies appears to overlie crevasse-splay deposits. These beds, which occur in red overbank siltstone and contain very abundant plant material, some of which has been altered to a coaly substance, are some 5 feet thick and measure well over 60 feet in lateral extent
The woody cells of the plant debris were in part converted to anthracite and in part replaced by pyrite. Replacement occurred at an early stage as evidenced by the lack of deformation of the replaced woody cells. Most of the pyrite has now been oxidized to hematite and limonite, probably by surface weathering. Even the anthracite, which usually resists oxidation, shows evidence of undergoing oxidation in this material. Surface oxidation was probably intensified by sulfate-bearing water derived from pyrite. The vitrinite reflectance of samples of this plant debris is 2.2% to 2.3%. The mean reflectivity of the vitrinites in oil using light with wavelength of 546 nm is 2.5%. This indicates that the vitrinite contains 93% to 94% fixed carbon, about 3.5% hydrogen, and other volatile matter. Locally the coalified plant chambers contain anhedral pyrite and galena: the paragenetic sequence is pyrite and then galena. The vitrinite (coalified woody tissue) contains micron-sized pyrite cubes. Outside the plant tissues, small amounts of chalcopyrite and possibly sphalerite are present (Friedman, 1987a,b; Friedman and Sanders, 1982 ). The deposits observed at this site were buried to a depth of 6.5 km for a duration of about 200 million years (Friedman and Sanders, 1982).
The steep cut-bank on the right of the lower channel may initially have extended upward for many more tens of feet and tapped sand from an earlier upper channel. Sand, now sandstone, moved down the cut-bank as a liquefied cohesion-less particle flow or grain flow and is now preserved as an inclined sand body paralleling the cut bank.
Bivalves of the Species Archanodon (= Amnigenia, Hall 1874) catskillensis (Heteroconchia, Archanodontacea) inhabited the back-swamp facies on the slip-off slope margin of the lower channel. These bivalves (up to 22 cm x 6 cm) are among the largest known fossil fresh-water pelecypods in geologic history. Unfettered, opportunistic growth in this swamp environment marked by rich organic matter and devoid of competition with other pelecypods, and possibly other benthic fauna of any kind, resulted in the unusually large sizes of these clams (Friedman and Chamberlain, 1995).
To the left of the point-bar sequence note on lap of stream facies on to an interpreted soil horizon.
Johnson and Friedman (1969, p. 463-468, including Figs. 7-17) provide a detailed description of this stop (their section 53); Figure 29 is a modified version of Figure 7 of Johnson and Friedman.

A7: TRAVERSE ACROSS THE TACONIAN OROGEN
KURT HOLLOCHER
Union College
Schenectady, NY 12308
In Early Ordovician time the rifted and submerged eastern edge of the North American continent (current coordinates) was located approximately at the present location of the Connecticut River in western New England (Figures 1A and 2). To the east, across a narrow ocean basin, lay an island arc. Subduction of oceanic crust beneath the arc allowed the arc to advance toward North America, colliding in Middle to Late Ordovician time. The remnants of the island arc itself are present in western New England as a sequence of Ordovician sediments (e.g., Bradley and Kidd, 1991) and bimodal volcanic and plutonic rocks (e.g., Leo et al., 1984; Leo, 1985, 1991; Schumacher, 1988; Hollocher, 1993, 1994). The remnants of the island arc are found in four different forms: 1) unmetamorphosed sediments derived from the arc and fore-arc regions that were deposited west of the arc on North American crust; 2) variously metamorphosed continental shelf, continental slope, trench, and fore-arc rocks that became part of the arc's accretionary wedge and were thrust westward onto North America during subduction and collision; 3) interbedded sediments and volcanics associated with arc, and possibly fore-arc and back arc volcanics; and 4) the plutonic roots to the arc. This trip examines all four of these.

A7: TRAVERSE ACROSS THE TACONIAN OROGEN

STOP 1. Rexford Bridge.
No hammers!
On the cliff across the Mohawk River you can see an excellent exposure of undeformed autochthonous Schenectady Formation, which is composed of interbedded gray shale and gray sandstone (graywacke). The sandstones are turbidite beds that are made of sediment derived from erosion of the Taconian island arc, and possibly associated emergent accretionary wedge and fore arc material (see Kidd et al., this volume). Flute casts and other current indicators in eastern New York State indicate a generally northward turbidity current transport direction, suggesting deposition in a north-south trending, northward-deepening sedimentary basin. Garver et al. (in press) has shown that there is a dramatic increase in Cr and Ni concentrations part way up the stratigraphic section in these rocks in New York State and similar rocks in Quebec and Newfoundland. They interpret this increase as resulting from erosional unroofing of mafic and ultramafic ophiolitic rocks that were exposed in the fore-arc region during the arc-continent collision. Ophiolites are still exposed in western Newfoundland and eastern Quebec, but, except for small ultramafic pods, have been eroded away in western New England. Unstable mineral grains and rock fragments in these gray sandstones have decomposed to form illite, chlorite, and other diagenetic minerals. The mineralogy of these rocks is dominated by quartz, illite, chlorite, and kaolinite.

STOP 2. Lock 7 access road.
This small roadcut has allochthonous "Schenectady Formation" that has been deformed. The thrust zone along which these rocks have been transported extends approximately 500 m to the west. Notice that these are still sedimentary rocks and have not been metamorphosed significantly. Graded beds and sole marks in some sandstones indicate topping direction. Note that this outcrop is about 6 km west of a klippe of Austin Glen Formation, the westernmost mapped klippe in the Schenectady area (Figure 1). This and surrounding outcrops probably represent a poorly exposed thrust slice that was transported a relatively short distance.

Ordovician Austin Glen Formation
Outcrops to left and right are Ordovician Austin Glen Formation. These weakly metamorphosed rocks have a strong east-dipping foliation, contain numerous small thrust faults, and is quite inhomogeneous, giving the outcrop a melange-like appearance.

Low Taconics visible in the distance ahead.

High Taconics visible on the skyline ahead.

STOP 3. Taconic crest.
These highly deformed rocks of the Nassau Formation had a shaley deep water facies protolith. Now they are chloritoid-grade phyllites with abundant deformed quartz veins (I have not found chloritoid in this outcrop). The quartz veins occur in several generations, as can be discerned by different degrees of deformation and crosscutting relationships. The phyllites contain the mineral assemblage quartz-white mica (muscovite and paragonite)-chlorite-carbonate (probably ankerite). The large rusty cavities in the quartz veins are weathered carbonate. Although two or three fold generations are apparent in the outcrop, the general dip of the schistosity is east, typical of the entire Taconian accretionary wedge system. Shear sense indicators suggest a top-to-the-west transport direction. Notice that the dominant foliation has been folded by a steeply east-dipping crenulation cleavage.

STOP 4. Pine Cobble.
Turn left into little the parking lot and park. This hike will be to Pine Cobble Long Trail. The hike is 3.2 miles round trip and 800' of climbing. It will take about 2.5 hours. Bring water, a snack, and appropriate clothing.
No hammers! This outcrop of Cheshire Quartzite is located on the southern tip of the Green Mountains, and is equivalent to the Potsdam Formation in New York State. This is the basal Cambrian clastic unit that overlies older rocks, including Grenville age metamorphic basement rocks, of the Green Mountains and Berkshires. The quartzite has a weak foliation defined by muscovite that dips gently east. A set of steeply east-dipping joints may be a fracture cleavage, because the joints have an orientation similar to the crenulation cleavage evident in the more ductile rocks at Stops 3 and 7, and are approximately parallel to the antiformal axial surface of the Green Mountains. The Taconic Mountains are visible to the west, Mt. Greylock to the south, and the Berkshires to the east. The mountains are held up by allochthonous metamorphic rocks that were thrust-transported westward in the Taconian accretionary wedge. The valley is floored by Cambrian and Lower Ordovician carbonate and clastic continental shelf rocks that stratigraphically overly the Cheshire Quartzite of this stop. The Cheshire and underlying rocks, which is part of a broad anticlinal structure that makes up the Green Mountains, plunges southward beneath the valley. The rocks in the valley floor are also allochthonous, having been transported piggyback-style on the Precambrian-based block of the Green Mountains. Hike back down, leave the parking lot and backtrack down Pine Cobble Rd.

Highlands to the left (north) are the southern end of the Green
Mtns.

STOP 5. Natural Bridge State Park.
No hammers!
These are rocks of the Cambrian to Ordovician Stockbridge Formation. This unit represents North American Cambrian or Lower Ordovician continental shelf carbonate rocks that were deformed and transported westward along Taconian thrusts. These have themselves been overridden by Taconian thrust sheets, including the Berkshire block immediately to the east.

STOP 6. Road cut on Rt. 8.
This rock is composed of relatively low-grade metamorphosed calcareous sandstone in the Ordovician Walloomsac Formation. This unit was also deposited on the North American continental margin. Although the rock is folded, sedimentary structures such as cross bedding can still be found in some places. The folds are best outlined by carbonate-rich layers in which the carbonate weathers out to form rusty pits.

STOP 7. Berkshires "western summit".
Excellent views of the Williamstown-North Adams valley with the Taconics, Mt. Greylock massif, Green Mtns., and the carbonate-floored valley.
This outcrop of Hoosac Formation contains biotite grade metamorphosed clastic sediments similar in composition to those seen at the Taconic crest. At these higher grades, biotite is the dominant mafic mineral rather than chlorite. Gray albite porphyroblasts up to 3 mm across are very common, and have grown to replace paragonite as the principal Na-bearing phase. Although the foliation generally dips east, there are numerous folds visible. Most are late, broad, open, folds having a prominent steeply east-dipping crenulation cleavage similar to that at Stop 3. More rare are isoclinal folds that indicate a top-to-the-west shear sense in the plane of the dominant foliation. This rock overlies Precambrian rocks in the Berkshire massif, and so it is part of a block of North American basement that has been transported westward over the shelf sediments seen at Stops 5 and 6.

STOP 8. Eastern Summit Gift Shop.
No hammers!
Excellent view of the eastern slope of the Berkshires, and the Bear Swamp pumped storage hydroelectric reservoir.
This glacially striated pavement outcrop of Rowe Formation contains garnet grade phyllite (but no garnets) that has a composition richer in Fe and Mg and poorer in K, Na, and Si than the schists and phyllites of Stops 3 and 6. This more mafic composition is probably caused by a large volcaniclastic component in the sediments, presumably derived from erosion of volcanics from the Taconian island arc. The dominant minerals are chlorite, white mica, quartz, and octahedral crystals of magnetite. The patchy appearance of the outcrop is caused by mechanical mixing of a variety of slightly different sedimentary lithologies, probably when the rock was a soft sediment. On a large scale, the Rowe Formation has been characterized as a melange, and includes basaltic and ultramafic rocks. Leave the parking lot and turn left (south) down the hill on Rt. 2 east. Units passed on the steep, winding descent of the Berkshires include the Rowe and Hoosac Formations.

Outcrops on right are Hawley Formation.

STOP 9. Hawley Formation.
The Hawley Formation contains large quantities of volcanic and intrusive rocks along with the volcaniclastic sediments. The igneous rocks include mafic and felsic varieties. The mafic rocks have compositions similar to basalts, and seem to include mid-ocean ridge, back-arc basin, and boninitic, and calc-alkaline varieties. These metamorphosed igneous rocks are related to the Taconian island arc, but their diverse lithology, compositions, and ages indicate a complex history for the island arc system in which they were emplaced. The rocks at this outcrop are amphibolite grade carbonate- and hornblende-bearing chlorite-muscovite schists. They contain abundant acicular hornblende up to 20 cm long in some areas, although they are typically 1 to 3 cm long in this outcrop. Euhedral carbonate rhombs (ankerite?) can be seen weathering out on outcrop surfaces to form rhombohedral pits. On the steep slope on the river side of the road there are some nice exposures of coticule (fine-grained pink garnet quartzite). This unusual rock type is thought to represent metamorphosed Mn- or Fe-rich chert that formed from silica derived from the weathering or hydrothermal alteration of volcanic rocks.

Devonian Goshen Formation
Good outcrops of garnet-rich Devonian Goshen Formation schist on the north shore of
the Deerfield River to the right (south).

Core rocks of the Shelburn Falls dome
Outcrops are calc-alkaline felsic gneisses and related amphibolites in core rocks of the Shelburn Falls dome (roots of the Taconian island arc).

STOP 10. Shelburn Falls.
Small access road to the right (south) soon after the bridge. Do not drive down this road, but find a place to park after the bridge. On foot, follow signs on the small access road to "glacial potholes". Find the steps going down to the river behind the gift shop. Do not go down to the rocks if the gate is locked, or if water is flowing strongly over the rocks.
This exposure is an excellent example of the core gneisses of the Shelburn Falls dome. This is an Acadian (Devonian) structural dome that exposes a variety of plutonic-looking calc-alkaline gneisses and amphibolites. These rocks have generally been interpreted to be part of the plutonic roots to the Taconian island arc. Igneous features that can be seen in this outcrop include crosscutting relationships, dikes, xenoliths, intrusion breccia, and late-stage quartz veins and faults. These rocks are similar to, but less deformed than, the Ordovician gneisses exposed in the cores of domes in the Bronson Hill anticlinorium, farther to the east. The precise relationship of the Shelburn Falls rocks to those in the Bronson Hill anticlinorium is somewhat problematic. Although the two are lithologically and chemically similar, a preliminary age date on the Shelburn Falls rocks is substantially older (Paul Karabinos, oral communication, 1993) than the 443-453 MY age of the calc-alkaline gneisses in the Bronson Hill anticlinorium (Tucker and Robinson, 1990). Other features that can be seen here include wonderful large potholes that were formed by the Deerfield River when it was swollen with glacial melt water.

Road climbs out of the topographic depression
Road climbs out of the topographic depression of the Shelburn Falls dome. Hills bounding the dome here are kyanite-staurolite grade Goshen Formation schists that are more resistant to erosion than the calc-alkaline gneisses in the dome interior.

Excellent view of the Deerfield basin
Excellent view of the Deerfield basin, the northernmost sizable portion of the Mesozoic rocks of the Connecticut River Valley. The N-S trending ridge in the middle of the basin is held up by the Deerfield Diabase, probably correlative with the Holyoke Basalt farther south. The large mountain to the southeast is Mt. Toby.

Excellent exposures of fluvial facies
Excellent exposures of fluvial facies of the Mesozoic red beds of the Connecticut Valley basin.

STOP 11. Turner's Falls.
Although it has little to do with the Taconian orogen, this wonderful set of outcrops has excellent exposures of Mesozoic basaltic lava and terrestrial sediments that formed in a rift valley. The outcrops near the parking lot are of tholeiitic Deerfield basalt. The flow base, in contact with red beds, is accessible on the south side of the road to the west of the parking lot. The flow base has pillow lavas that formed as the lava flowed into a saline rift valley lake. The flow top and overlying red beds are visible in the roadcut across the road from the eastern end of the parking lot. Several faint, coarse-grained layers sub-parallel to the flow top are visible in the central part of the roadcut. These are sill-like segregations of residual magmatic liquid that separated from the crystal mush of the compacting, solidifying flow (described for a different locality by McHone and Philpotts, 1995; Philpotts et al., 1995). The outcrops near the river, accessible by foot path from the parking lot, have excellent exposures of the vesicular lava flow top, and one of the coarse-grained sill-like layers. The flow is overlain by fluvial conglomerate, arkose, siltstone, and shale. The fluvial sediments have excellent depositional and soft sediment features including bed forms, mud cracks, trace fossils, raindrop imprints, shale rip up clasts, and filled channels. Near the dam the sediments grade into finer-grained gray and black lake sediments in which fish and plant fossils can be found. Leave the parking lot and turn right to continue on Rt. 2 east. For excellent introductions to the geology of the Connecticut Valley basin, see Hubert eta!. (1978) and Home et al. (1995).

Very coarse-grained matrix-supported conglomerate.
Small road cuts on both sides of the road are composed of very coarse-grained matrix-supported conglomerate. This outcrop represents the alluvial fan facies of the Mesozoic red beds of the Connecticut River Valley. The alluvial fans were principally built on the east side of the basin, below the mountains on the east side of the border fault along which the basin subsided.

Cross the French King Bridge over the Connecticut River.
This is the approximate location of the normal fault that forms the eastern margin to the Connecticut River Valley rift basin.

STOP 12. Millers Falls.
This large roadcut is in the biotite member of the Dry Hill Gneiss, a Late Precambrian (Tucker and Robinson, 1990) unit exposed in the core of the Pelham dome, one of the structural domes in the Bronson Hill anticlinorium. This unit is interpreted to be a thick series of metamorphosed alkalic volcanics that probably erupted in a continental rifting environment (Hodgkins, 1985). The relationship of these rocks to surrounding rocks is unclear, but they are unrelated to the Taconian island arc except to the extent that they are exposed in this dome in the Bronson Hill anticlinorium. The Dry Hill Gneiss is overlain, perhaps along a fault, by felsic Fourmile Gneiss, which is part of the Taconian igneous suite. The Dry Hill Gneiss is a moderately well foliated, layered granitic gneiss that contains the assemblage quartz-plagioclase-microcline-biotite±amphibole (hornblende or hastingsite), with accessory sphene, magnetite, apatite, zircon, and allanite. The allanite crystals are large and are visible as dull tan-colored crystals in hand specimen. The large K-feldspar megacrysts in the gneiss were probably derived from severely deformed and dismembered pegmatites. This texture indicates the great strength of feldspar compared to the quartz- and biotite-rich matrix during extreme solid-state deformation.

STOP 13. Crag Mountain.
Pull off to the right at the top of the hill and park. Follow white blazes along the private driveway. At the double blaze, turn right into the woods. Follow the trail to the quartzite ledges after about 1/4 mile.
This prominence is composed of thickened (by folding) Silurian Clough Quartzite. In this locality it is a quartz pebble and cobble conglomerate metamorphosed to kyanite-staurolite grade. Pelitic schists in the area can contain the assemblage The Clough Quartzite was deposited on an extensive Silurian erosion surface in western New England, and it rests on a variety of Ordovician and older rocks. The quartzite has been deformed so that quartz cobbles and pebbles have been flattened and extended to different degrees, visible in outcrop. The milky quartz is full of fluid inclusions, suggesting that it was originally metamorphic vein quartz. Silurian erosion of Taconian low- and medium-grade metamorphic rocks in the Taconics, Green Mountains, and Berkshires may have been the source for the necessary large quantities of high-purity vein quartz. End of trip!

A8: DEVONIAN CARBONATES AND ECONOMIC RESOURCES: THE BLUE CIRCLE AND CALLANAN QUARRIES
DEAN HERRICK
Continental Placer
26 Computer Drive West
WILLIAM KELLY
Room 3140 CEC
DON DRAZAN
Division of Mineral Resources
New York State Department of Environmental Conservation
50 Wolf Road, Albany, NY 12233
CRUSHED STONE AND CEMENT PRODUCTION - GENERAL CONSIDERATIONS
The production of crushed stone in New York was 33,500,000 tons 1994 with a value of $196 million. Most of the crushed stone produced in New York is limestone and dolostone with traprock (diabase) and various metamorphic rocks making up the bulk of the remainder. Cement manufacturing amounted to 2,925,000 tons valued at slightly over $149 million. Taken together, crushed stone and cement account for 40% of the value of mineral produced in New York. There is an order of magnitude difference in the price of these two commodities with crushed stone trading for an average of $5.85/ton and cement valued at an average of $50.94/ton. This price difference leads directly to the contrast in mining operations that will be examined. On this field trip, we will visit two quarries operating in the rocks of the Helderbergs. One of these produces crushed stone for construction aggregate and the other produces cement. Although both companies are working in the same stratigraphic section with similar equipment and mining plans, the end use of the rock drives the companies to use very different geologic units within the overall stratigraphic framework. The following brief discussion outlines the processes and constraints on the construction aggregate and cement industries.

A8: DEVONIAN CARBONATES AND ECONOMIC RESOURCES: THE BLUE CIRCLE AND CALLANAN QUARRIES

STOP 1. Callanan Quarry
SITE GEOLOGY
The Callanan Quarry is located primarily in the Town of Coeymans, south of NY Route 396 and the village of South Bethlehem (Fig. 1). The location can be found on the Delmar 7.5' quadrangle. The quarry is owned and operated by Callanan Industries, Inc. All correspondence concerning access should be directed to Mr. Charles A. Stokes, Senior Vice-President, Callanan Industries, One South Street, South Bethlehem, NY 12161. The Blue Circle Quarry is located in the town of Coeymans, east of NY Route 9W (Fig. 1 ). The location can be found on the Ravena 7.5' quadrangle. Correspondence concerning quarry access should be directed to Mr. Kevin Riley, Quarry Superintendent, Blue Circle Industries, Ravena, NY 12143.
The two quarries described herein are separated from each other by nine miles. Consequently the geology at the two sites is quite similar. Both quarries are developed in the lower and middle units of the Helderberg Group rocks. Here, the Manlius is 54 feet thick and subdivided as described above. Units M1, M3, and M6 are dark-gray, fine-grained to sublithographic, fine to medium bedded, subtidal limestone. Units M2 and M5 are light-gray, fine-grained, thin-bedded, super-tidal dolomitic limestone. Unit M4 is medium to dark-gray, massive, intertidal, stromatoporoid limestone. The Coeymans is 27 feet thick, light-gray, medium-grained, massive, non-argillaceous, fossiliferous limestone. It is homogeneous and lacks marker beds.
The Kalkberg is 66 feet in total thickness. The Lower Hannacroix is 11-18 feet thick, medium-gray, medium-bedded limestone with interbedded dark gray to black chert nodules and chert beds one to four inches thick. The Upper Hannacroix is 10 feet thick, fine- to medium-grained limestone. This unit is similar to the Coeymans except that it is less fossiliferous and the fossils are somewhat smaller. The Lower and Upper Broncks Lake total 45 feet in thickness. They are fine- to medium-grained, medium-bedded, argillaceous limestones.
The New Scotland is 100 feet thick and is composed of medium to thick-bedded, argillaceous limestone similar in appearance to the Kalkberg Formation. The uppermost part of the New Scotland is transitional into the overlying Becraft. The Becraft is 40 feet thick, tan to grayish-white with greenish-gray shaly partings. It is a coarse-grained and highly fossiliferous limestone.
Several marker beds and stratigraphic horizons are visible in the quarries and can be used for stratigraphic location. The Coeymans-Kalkberg contact is a key horizon. This contact can be identified by the following characteristics: (1) on a weathered surface, the Coeymans is light-gray to buff and the Kalkberg is medium-gray and is less resistant to weathering; (2) a black, shaly layer, two to six inches thick, commonly occurs between the formations; (3) the Lower Hannacroix of the Kalkberg contains discontinuous bedded black chert.
The contact between the Kalkberg and New Scotland is marked by an increase in siliceous material in the New Scotland giving it a shaly appearance relative to the more massive Upper Broncks Lake Member of the Kalkberg.
The top of the New Scotland contains a transitional zone into the overlying Becraft Formation characterized by alternating beds of crystalline (Becraft lithology) and shaly beds (New Scotland lithology). Also notable at the contact are green shale bands of the Becraft as opposed to the black shale of the New Scotland.
PRODUCTION
The majority of the aggregate produced from the Callanan Quarry in South Bethlehem is used for New York State Department of Transportation (NYSDOT) road construction. Therefore, NYSDOT specifications are most crucial to Callanan's mining. High-friction aggregate, material with greater than 20% non-carbonate content, is used in top-coarse paving material in New York State. High-fiction material commands the highest price, and, for this reason, is the most valuable to producers. Of the five formations mined at Callanan's quarry, only the New Scotland and Kalkberg are approved for high-friction use. As Callanan excavates the New Scotland and Kalkberg, most of the Manlius, Coeymans and Becraft is left behind. These formations are, however, mined for non-friction products, which include commercial uses.

STOP 2. Blue Circle Quarry
A few miles south, the situation is startlingly different. Blue Circle is discarding in waste piles approximately 85% of the Kalkberg and nearly 100% of the New Scotland that is mined. Callanan's low-valued Manlius, Coeymans and Becraft formations command high value at Blue Circle's quarry. These three formations have a high carbonate content which is extremely important in cement production. So much so that Blue Circle strips up to 160 feet of waste rock (rock which is valuable to Callanan) to get to the Manlius and Coeymans formations. A comparison of the cost per ton of aggregate versus cement in New York, cited above, illustrates the difference in value and explains Blue Circle's mining strategy. The much higher cost (and value) of cement is attributed to a number of factors including processing costs, cost of raw materials (limestone, iron, silica, alumina, gypsum) and market demand.

A9: THE PALEOFLUVIAL RECORD OF GLACIAL LAKE IROQUOIS IN THE EASTERN MOHAWK VALLEY, NEW YORK
Gary R. Wall & Robert G. LaFleur
West Hall
Troy, NY 12180
During the final retreat of Laurentide ice from New York State, the Mohawk Valley played a major role in the routing of glacial meltwater. The Mohawk Valley contained the Iromohawk River, which drained Glacial Lake Iroquois, in the Ontario Basin, into Hudson Valley glacial lakes Albany II, Quaker Springs, Coveville and Fort Ann. Iromohawk drainage occurred for a period of approximately 500 years while the St. Lawrence Lowland remained glaciated and the Mohawk Valley was ice free.
Iromohawk drainage developed a network of distributary channels across the Hudson-Mohawk Lowland, as well as carving the modern Mohawk channel between Schenectady and Cohoes. Progradation of these channels occurred as the Iromohawk drained toward lowering Hudson Valley glacial lake levels. Depositional and erosional surfaces associated with distributary and modern channels have been used to establish a chronology of channel development and usage relative to Hudson Valley glacial lakes. This chronology constrains the timing and duration of later Hudson Valley lake phases between -12,500 and 12,000 years BP.
Sedimentologic evidence in the Scotia Gravel at Scotia, one of the principle Iromohawk deposits in the valley, indicates Iromohawk drainage was a long-term, high-discharge event with cyclic (probably seasonal) variation in flow.

A9: THE PALEOFLUVIAL RECORD OF GLACIAL LAKE IROQUOIS IN THE EASTERN MOHAWK VALLEY, NEW YORK

Schoharie Bridge
The original Thruway crossing of Schoharie Creek catastrophically failed in 1987 due to Schoharie Creek high flow and scour of bridge supports.

Approximate Iromohawk River channel bottom
Mohawk River floodplain and approximate Iromohawk River channel bottom. Iromohawk depth in this location was approximately 50 feet.

Mohawk River and Barge Canal on right.

Middle Ord. Canajoharie Shale exposed on left.

STOP 1. Randall Expansion Bar overview.
Uplifted land associated with the Noses fault is visible to the west. At the base of the hill is the Iromohawk channel bottom, and beyond that the Randall expansion bar. The bar measures 7,000 feet in length and 1,800 feet at its maximum width. Thickness of the deposit is approximately 60 feet. One well log from the deposit indicates the bottom of the bar is approximately at the elevation of the modern floodplain (U.S. Geological Survey, Open File). The height of the bar above the floodplain therefore represents a minimum water depth (60 feet) for bar deposition.

Road descends to Iromohawk channel bottom.
Randall bar is straight ahead and to the right

Road climbs along Randall bar long axis.

STOP 2. Randall Expansion Bar.
Pit owned by Santos Construction Company (SCC) - our access to the pit is under consideration by SCC.
Contact: Dave Santos (owner) (518) 842-6201
Large-scale east--dipping (downvalley) cross-bedding is visible throughout the exposed pit, confirming the eastward flow direction inferred from the deposits east-pointing tapered tail. Exposures in contact with the deposit surface show bedding that mimics external morphology. Overall, the Randall deposit is very poorly sorted with individual clasts ranging from small boulders to coarse sand.

Road descends along eastern tail of Randall bar.

Road crosses top of Rotterdam Jct. portion of Scotia Gravel

Cross Mohawk River and Barge Canal Lock 9

Glenville Channel visible on left
Glenville Channel visible on left- one of four minor channels to incise the Scotia deposit of Scotia Gravel.

Partially cemented blocks of Scotia Gravel
Partially cemented blocks of Scotia Gravel visible in old pit on left

STOP 3. Scotia Gravel and Mohawk River overlook.
If water level is low and interest high, hike from here to exposure of graded gravel foresets.
This exposure is marked by numerous east dipping graded gravel foreset beds. Dozens of these foresets are visible across the exposure, each grading from cobble to coarse sand and pebble gravel, and measuring approximately 3 feet in thickness. The cyclic nature of the graded foresets is more typical of a long term rather than catastrophic depositional event; furthermore, the cyclically suggests a seasonal variation transport energy, essentially gravel varves.

Top of Scotia Gravel (-300' asl).
Deposit continues to the northern (left) valley wall (3000+ feet)

Giant point bar
This stretch of Rt. 5 runs along the top of a giant point bar extending to the south (right) into Schenectady Basin.

Road climbs to top of Scotia Gravel.

STOP 4. Scotia Gravel overlook and paleodischarge discussion.
Another Scotia Gravel overlook, this one into a semi-active gravel pit.

Road parallels Harding Channel on left.

Schenectady County Airport on right.
The airport sits atop a sand plain deposited in Lake Albany by the Glaciomohawk (pre-Iromohawk) and/or Alplaus Kill.

Road descends into Ballston Channel.

Bottom of Ballston Channel.

Road climbs out of channel.

STOP 5. Mohawk Gorge
Directly across the gorge, a 1,200 foot wide bedrock bench stands at ∼270 feet elevation. This bench descends and narrows to 260+ feet elevation some 6,000 feet downvalley where it pinches out at the narrowest gorge reach. A lower bedrock bench stands at 220+ feet.

Village of Vischers Ferry
Village of Vischers Ferry is built on the floor of Niskayuna Basin, the southernmost of three giant kettles in the Hudson Mohawk Lowland. Niskayuna Basin is roughly 4 miles (E-W) by 2 miles (N-S). All three basins lie along the N-S trending preglacial Colonie Channel.

Original Erie Canal visible on right.

Road leaves Niskayuna Basin

Mohawk River on right.

STOP 6. Cohoes Falls
The falls are dry throughout most of the year due to a diversion of flow for the Barge Canal and the hydroelectric plant immediately to the west.
Cohoes Falls has eroded back some 2000+ feet in post-glacial time. Inferences from bedrock islands at the Hudson-Mohawk confluence immediately downvalley suggest much of this erosion may have occurred during Iromohawk drainage. Iromohawk flow exposed and eroded the top of bedrock on both sides of the gorge.

Cross Mohawk River
Bedrock islands visible to right.

Barge Canal locks 2 and 3
Barge Canal locks 2 and 3 visible to right and left respectively

Enter Anthony Kill Channel
This channel developed as Round Lake Basin waters drained toward falling Hudson Valley glacial lake levels.

Willow Glen channel expansion (on right).
Anthony Kill Channel dramatically expands to the north. This feature was likely carved out by eddying flow through Anthony Kill Channel, eroding the less resistant Willow Glen kame delta (the majority of the channel walls are composed of till and bedrock).

STOP 7. Anthony Kill Channel.
A classic example of a misfit stream.

Enter Round Lake Basin
Enter Round Lake Basin, the middle of three giant kettles aligned with the preglacial Colonie Channel. Round Lake Basin is nearly circular with a diameter of apx. 2.5 miles

Road crosses top of small delta at mouth of Round Lake Channel.

Cross Round Lake Channel.
Flow was from left to right into Round Lake Basin.

STOP 8. Round Lake Channel
Visible in this portion of Round Lake Channel are two bedrock erosional surfaces which grade to Round Lake Basin water levels correlative with lakes Coveville and Fort Ann in the Hudson Valley. The upper Coveville surface is distinguished from the lower Fort Ann by the bedrock channel wall flanking Rhule Rd. No. The opposite channel wall is visible below the power lines crossing the channel.

Malta Sand Plain
Road runs across the Malta Sand Plain, a Glaciomohawk deposit into Lake Albany II.

Road descends into Saratoga Lake Basin
Road descends into Saratoga Lake Basin, the northernmost of three giant kettles aligned with the preglacial Colonie Channel. Saratoga Lake Basin has approximate dimensions of 2 miles (E-W) by 6 miles (N-S).

Saratoga Lake is visible straight ahead.

Ascend back onto Malta Sand Plain.

Road descends into Ballston Channel.
Ballston Channel is the middle of three distributary channels branching from the northern end of Ballston Channel at East Line. Drummond Channel connects with Saratoga Lake Basin to the northeast (right).

Road ascends out of channel onto Malta Ridge
Road ascends out of channel onto Malta Ridge, an erosional remnant between distributary channels (Drummond and Mourning) equivalent with the Malta Sand Plain.

Road parallels Mourning Channel (to right).

East Line
Point at which Ballston Channel splits into the distributary Mourning, Drummond, and Round Lake Channels.

STOP 9. Northern end of Ballston Lake
Northern end of Ballston Lake in Ballston Channel.

A10: GEOCHRONOLOGY AND PETROGENESIS OF ADIRONDACK IGNEOUS AND METAMORPHIC ROCKS
James M. McLelland
INTRODUCTION AND GEOCHRONOLOGY
The Adirondacks form a southwestern extension of the Grenville Province and are physiographically divided into the Adirondack Highlands (granulite facies) and Lowlands (amphibolite facies) by a broad zone of high strain referred to as the Carthage-Colton Mylonite Zone which is continuous with the Chibougamau-Gatineau line, or Labelle shear zone, in Canada. Together these two zones separate the Grenville Province into two major blocks with the Central Granulite Terrane (CGT) lying east of AB and the Central Metasedimentary Belt (CMB) and Central Gneiss Belt (CGB) lying to the west. Within the southwestern portion of the Grenville Province further subdivisions exist and are shown in figure 3. As demonstrated by recent U-Pb zircon and Sm-Nd geochronology summarized by McLelland and Chiarenzelli (1990) and McLelland et al. (1993), the Adirondack-CMB sector of the Grenville Province contains large volumes of metaigneous rocks that represent recent (i.e., ca. 1400-1200 Ma) additions of juvenile continental crust. These results indicate that the Adirondack-CMB region experienced wide-spread calcalkaline magmatism ca. 1300-1220 Ma. Associated high grade metamorphism has been fixed at 1226±10 Ma by Aleinikoff (pers. comm.) who dated dust air abraded from metamorphic rims on 1300 Ma zircons. Identical rocks, with identical ages, have been described from the Green Mts. of Vermont by Ratcliffe et al. (1991), in northern Ireland by Menuge and Daly (1991), in the Llano uplift of Texas (Walker, 1993) and in the Texas-Mexico belt of Grenville rocks by Patchett and Ruiz (1990). It appears, therefore, that a major collisional-magmatic belt was operative along the present southern flank of the Grenville Province during the interval 1300-1220 Ma and may have been related to the assembly of a supercontinent. More locally, this magmatism and associated metamorphism, represents the Elzevirian Orogeny of the Grenville Orogenic Cycle as defined by Moore and Thompson (1980). Within the Adirondacks, Elzevirian rocks are represented by 1300-1220 Ma tonalites and alaskites whose distribution is shown in figure 5. The apparent absence of this suite from the central Highlands is believed to be the combined result of later magmatic intrusion and recent doming along a NNE axis. Within the Frontenac-Adirondack region, the Elzevirian Orogeny was followed by 40-50 Ma of quiescence terminated at 1170- 1130 Ma by voluminous anorogenic magmatism referred to as the anorthosite-mangerite-charnockite-granite (AMCG) suite. The older ages are characteristic of AMCG magmatism in the Frontenac Terrane (including the Lowlands) while the Highlands commonly exhibit ages of 1150-1130 Ma. The large Marcy anorthosite massif and its associated granitoid envelope were emplaced at ca. 1135 Ma (McLelland and Chiarenzelli, 1990). These ages are similar to those determined (Emslie and Hunt, 1990) for the Morin, Lac St. Jean, and several other large massifs farther northeast in the Grenville Province. Rocks of similar age and chemistry (i.e., Storm King Granite) have been described within the Hudson Highlands (Grauch and Aleinikoff, 1985). The extremely large dimensions of the AMCG magmatic terrane emphasize its global-scale nature corresponding, perhaps, to supercontinent rifting with the rifting axis located farther to the east. Valley et al. (1990) and McLelland et al. (1991) have provided evidence that contact, and perhaps also regional, metamorphism accompanied emplacement of hot (1100°C), hypersolvus AMCG magmas. Wollastonite and monticellite occurrences related to thermal pulses from AMCG intrusions occur in proximity to AMCG intrusions (Valley et al., 1990). In the Lowlands and the Canadian sector of the Frontenac Terrane, monazite (table 1., no. 28), titanite, and garnet ages (Mezger et al., 1992) all indicate high temperatures (600-8OO°C) at ca. 1150 Ma. Rutile ages and Rb/Sr whole rock isochron ages document temperatures not exceeding 400°C at ca. 1050-1000 Ma.
Following approximately 30 Ma of quiescence, the Adirondacks, along with the entire Grenville Province, experienced the onset of the Ottawan Orogeny of the Grenville Orogenic Cycle. Initially the Ottawan Orogeny was represented by 1090-1100 Ma hornblende granites in the northwest Highlands. These rather sparse granites were followed by deformation, high grade metamorphism, and the emplacement of trondhjemitic to alaskitic magnetite-rich rocks (Lyon Mt. Gneiss of Whitney and Olmsted, 1988) in the northern and eastern Adirondacks. The zircon ages of these rocks fall into an interval of 1050-1080 Ma which corresponds to the peak of granulite facies metamorphism when crust, currently at the surface, was at 25 km. Accordingly, the alaskitic to trondhjemitic rocks are interpreted as synorogenic to late-orogenic intrusives. They were followed by the emplacement of small bodies of fayalite granite (ca. 1050 Ma) at Wanakena and Ausable Forks.
Sm-Nd analysis (Daly and McLelland, 1991) demonstrates that the emplacement ages of the ca. 1300 Ma tonalitic rocks of the Highlands correspond closely to their neodymium model ages indicating that these represent juvenile crustal additions. As seen in figure 6, εNd evolution curves for AMCG and younger granite suites pass within error of the tonalitic rocks and suggest that the tonalites, together with coeval granitoids, served as source rocks for succeeding magmatic pulses. Remarkably, none of these igneous suites gives evidence for any pre-1600 Ma crust in the Adirondack region and the entire terrain appears to have come into existence in the Middle to Late Proterozoic. Significantly, Sm-Nd analysis for the ca. 1230-1300 Ma tonalitic to alaskitic Hyde School Gneiss at the Lowlands demonstrates that it has model neodymium ages and εNd values similar to Highland tonalites (McLelland et al., 1993). These results are interpreted to reflect the contiguity of the Highlands and Lowlands at ca. 1300 Ma. Given this, the Carthage-Colton Mylonite Zone is interpreted as a west-dipping extensional normal fault that formed during the Ottawan Orogeny in response to crustal thickening by thrust stacking (McLelland et al., 1993). East dipping extensional faults of this sort and age have been described by van der Pluijm and Carlson (1989) in the Central Metasedimentary Belt. Motion of this sort along the Carthage-Colton Mylonite Zone would help to explain the juxtaposition of amphibolite and granulite facies assemblages across the zone. A downward displacement of 3-4 km would satisfactorily explain the somewhat lower grade of the Lowlands terrane.

A10: GEOCHRONOLOGY AND PETROGENESIS OF ADIRONDACK IGNEOUS AND METAMORPHIC ROCKS

STOP 1. Peck Lake Fm.
This exposure along Rt. 29A just north of Peck Lake is the type locality of the sillimanite-garnet-biotite-quartz-feldspar gneisses (kinzigites) of the Peck Lake Fm. in addition, there are exposed excellent minor folds of several generations. Note that the F1 folds rotate an earlier foliation. The white quartzo-feldspathic layers in the kinzigites consist of quartz, two feldspars,and garnet and are believed to be anatectic and have been folded by F1 indicating pre-F1 metamorphic events. Typical whole rock compositions are shown below. Spinel has been found enclosed in garnets at this outcrop. The similarity of the Peck Lake Fm. to the Major Paragneiss of the Lowlands suggests that the Adirondacks were contiguous at the time of deposition of the rocks.

STOP 2. Irving Pond Fm., .5 mile north of Nick Stoner's Inn, Canada Lake .
.5 mile north of Nick Stoner's Inn, Canada Lake. Very near hinge line of F1 Canada Lake isocline.
The outer portion of the Irving Pond Fm. is exposed in low cuts along the east side of Rt. 29A just prior to the crest in the road heading north.
At the southern end of the cut typical, massive quartzites of the Irving Pond are seen. Proceeding north the quartzites become "dirtier" until they develop sillimanite-garnet-biotite feldspar (kinzigites) layers along with quartzite.
At the northern end of the cut, and approximately on the Irving Pond/Canada Lake Fm. contact there occurs an excellent set of F1 minor folds. Polished slabs and thin sections demonstrate that these fold an earlier foliation defined by biotite flakes and flattened quartz grains.
At the southern end of the outcrop dark, fine grained metadiabase sheets crosscut the quartzite. Near the telephone pole erosional remnants of diabase appear to truncate approximately horizontal foliation in the quartzite suggesting that the diabase was emplaced after an early metamorphism. At the north end of the cut a diabase sheet of variable thickness is folded in the F1 fold. The folding is interpreted as Ottawan, the diabase as AMCG in origin, and the early foliation as Elzevirian. This is consistent with the presence of quartzite xenoliths in the ca. 1300 Ma tonalites.
The Irving Pond Fm. is the uppermost unit in the lithotectonic sequence of the southern Adirondacks. Its present thickness is close to 1000 meters, and it is exposed across strike for approximately 4000 meters. Throughout this section massive quartzites dominate.

STOP 3. Canada Lake Charnockite
Large roadcuts expose the type section of the Canada Lake charnockite. Lithologically the charnockite consists of 20-30% quartz, 40-50% mesoperthite, 20-30% oligoclase, and 5-10% mafics. The occurrence of orthopyroxene is sporadic. These exposures exhibit the olive-drab coloration that is typical of charnockites. Note the strong foliation in the rock. Farther north along the highway there are exposed pink leucogranitic variants of this unit. The chemical composition of these is given in table 3 (ab-6). The whole rock chemistry of the charnockitic phase is similar to AM-86- I 7 in table 3. The lateral continuity of the Canada Lake is striking (fig. 2) but the presence of xenoliths reveals an intrusive origin.

STOP 4. Royal Mt. Tonalite
(>1301 Ma, table I, sample AM-86-12, now fixed at 1307±2 Ma).
Steep roadcuts, exposed across from the Canada Lake Store, expose typical examples of the early tonalitic rocks that occur within the southern and eastern Adirondacks and that manifest the presence, throughout the region, of collisional magmatic arcs of calcalkaline chemistry that existed along the eastern margin of Laurentia from ca. 1400-1200 Ma. Amalgamation of these arcs culminated in the Elzevirian Orogeny at ca. 1250-1220 Ma.
The whole rock chemistry of the tonalitic rocks is given in table 3. Figure 7 shows the εNd characteristics of these rocks and emphasizes their petrologically juvenile character, i.e., they are not derived from any crustal rocks with long-term crustal residence but are essentially mantle derived (including derivation from melting of basaltic rock derived from the mantle at ca. 1300-1400 Ma). The εNd characteristics are compared with those from Lowland tonalites and granitoids of similar age, and the similarity suggests that they are essentially the same, strongly suggesting contiguity across the entire Adirondacks at that time (∼1300 Ma).
A disrupted layer of amphibolitic material runs down the outcrop to road level at the east end of the outcrop. This, and other mafic sheets in the outcrop, are interpreted as dikes and sheets coeval with the tonalite. In the eastern Adirondacks it has been possible to document mutually crosscutting relationships between these rock types. Also documented there are xenoliths of kinzigitic rock in the tonalites. Within the southern Adirondacks xenoliths of quartzite similar to the Irving Pond Fm. have been found in the tonalite.

STOP 5. Rooster Hill megacrystic gneiss at the north end of Stoner Lake.
This distinctive unit belongs to the AMCG suite and is widespread in the southern Adirondacks. Here the unit consists of a monotonous series of unlayered to poorly layered gneisses characterized by large (1-4") megacrysts of perthite and microcline perthite. For the most part these megacrysts have been flattened in the plane of foliation, however, a few megacrysts are situated at high angles to the foliation and show tails. The groundmass consists of quartz, oligoclase, biotite, hornblende, garnet, and occasional orthopyroxene. An igneous rock analogue would be monzonite to quartz-monzonite and the presence of orthopyroxene makes the rock mangeritic to charnockitic.
The contacts of the Rooster Hill megacrystic gneiss are everywhere conformable, but the presence of xenoliths of kinzigite indicate its intrusive nature. Rocks such as the Rooster Hill are interpreted as derived from melting of ca. 1300 Ma tonalitic and lower crustal granitoid rocks with heat derived from large AMCG gabbroic intrusions that would ultimately differentiate to anorthosite. This suggestion is consistent with the εNd trends of AMCG and tonalitic rocks in figure 6a and with the REE distributions shown in figure 14, where it appears that melting of tonalite so as to leave a plagioclase-rich residue can give the AMCG REE-trends.

Long roadcuts of quartzo-feldspathic gneisses and metasediments
Long roadcuts of pink quartzofeldspathic gneisses and metasediments of intruded metagabbro and anorthosite metagabbro. The igneous rocks are believed to belong to the AMCG suite.

Pink granitic gneiss of AMCG suite
Pink granitic gneiss of AMCG suite intruded by anorthositic AMCG gabbros and gabbroic anorthosites. Large boudin of calcsilicate in granite.

Roadcuts of Sacandaga Fm 1154 mya
Roadcuts of quartzites and other metasediments of the Sacandaga Fm. Mezger (1990) obtained a U-Pb garnet age of ca. 1154 from these rocks.

Stop 6. Core rocks of the Piseco anticline.
This stop lies along the hinge line of the F2 Piseco anticline near its domical culmination at Piseco Lake. The rocks here are typical of the granitic facies of quartzofeldspathic gneisses such as occur in the Piseco anticline and in other large anticlinal structures, for example Snowy Mt. dome, Oregon dome.
The pink "granitic" gneisses of the Piseco anticline do not exhibit marked lithologic variation. Locally grain size is variable and in places megacrysts seem to have been largely grain size reduced and only a few small remnants of cores are seen. The open folds at this locality are minor folds of the F2 event. Their axes trend N70W and plunge 10-15° SE parallel to the axis of the Piseco anticline.
The most striking aspect of the gneisses in the Piseco anticline is their well-developed lineation. This is expressed by rod, or pencil-like, structures which are clearly the result of ductile extension of quartz and feldspar grains in a granitic protolith. The high temperature, grain size reduction that has occurred results in a mylonite. Where recognizable, early F4 isoclinal fold axes parallel the lineation.
These rocks are similar in age and chemistry to other AMCG granites and are considered to be part of that suite.
Smooth outcrops of Piseco Core rocks showing exceptionally strong mylonitic ribbon lineations.

STOP 7. Typical Adirondack marble is exposed in roadcuts on both sides of the highway.
Northern intersection of old Rt. NY 30 and new Rt. NY 30, 3.3 miles east of Speculator, New York.
Typical Adirondack marble is exposed in roadcuts on both sides of the highway. These exposures show examples of the extreme ductility of the carbonate-rich units. The south wall of the roadcut is particularly striking, for here relatively brittle layers of garnetiferous amphibolite have been intensely boudinaged and broken. The marbles, on the other hand, have yielded plastically and flowed extensively during the deformation. As a result, the marble-amphibolite and marble-charnockite relationships are similar to those that would be expected between magma and country rock. Numerous rotated, angular blocks of amphibolite and charnockite are scattered throughout the marble in the fashion of xenoliths in igneous intrusions. At the eastern end of the outcrop tight isoclinal folds of amphibolite and metapelitic gneisses have been broken apart and rotated. The isolated fold noses that remain "floating" in the marble have been aptly termed "tectonic fish". The early, isoclinal folds rotate on earlier foliation. The garnetiferous amphibolites have typical igneous compositions and are interpreted as flows or sills.
Near the west end of the outcrop a boudin of charnockite is well exposed. McLelland and others (1987) have presented evidence that boudin represents a local example of charnockitization by carbonic metamorphism. However, granites of similar composition outside the marble do not develop orthopyroxene, demonstrating the local nature of the process and the limited permeation of the fluid phase.
Exposed at several places in the roadcut are crosscutting veins of tourmaline and quartz displaying a symplectic type of intergrowth. Other veins include hornblende- and sphene-bearing pegmatites.
Almost certainly these marbles are of inorganic origin. No calcium carbonate secreting organisms appear to have existed during the time in which these carbonates were deposited (>1200 Ma ago). Presumably the graphite represents remains of stromatolite-like binding algae that operated in shallow water, intertidal zones. This is consistent with the presence of evaporitic minerals, such as gypsum, in Lowland marbles.
At the eastern end of the outcrop coarse diopside and tremolite are developed in almost monomineralic layers. Valley et al. (1983) showed that the breakdown of almost Mg-pure tremolite to enstatite, diopside, and quartz in these rocks requires low water activity at the regional P,T conditions. Similarly, the local presence of wollastine requires lowering of CO2 activity, presumably by H2O. These contrasts demonstrate the highly variable composition of the fluid phase and are consistent with a channelized fluid phase within a largely fluid-absent region.

Extensive roadcuts in lower part of marble.
Quartzites, kinzigites, and leucogneisses dominate. Minor marble and calcsilicate rock is present.

STOP 8. Anorthositic rocks on the SW margin of the Oregon Dome.
One half mile south of southern intersection of old Rt. 30 and with new Rt. 30.
On the west side of the highway a small roadcut exposes typical Adirondack anorthosite and related phases.
The glacially smoothed upper surface of the roadcut reveals the presence of three major igneous phases: 1) a dark, pyroxene-rich dike that crosscuts the anorthosite, contains anorthosite xenoliths, and contains a large irregular, disrupted mass of sulfidic calcsilicate; 2) a coarse grained, Marcy type anorthosite facies with andesine crystals 6-8" across; and 3) a fine grained anorthositic phase. Some of the coarse grained facies has been crushed and these portions bear some resemblance to the finer grained phase (note, for example, those places where fractures cross large andesine grains and produce finer grained material). However, close inspection of the finer grained material reveals the presence of ophitic texture with pyroxenes of approximately the same size as the plagioclase, and this texture and association are much better explained as igneous in origin. Therefore, the texture of the fine grained phase is interpreted as igneous in origin and may be due to chilling near the contact of the Oregon Dome massif. By contrast, large (3-4 cm) rafts of coarse grained, ophitic gabbroic anorthosite seem to be "flat" in the fine grained phase. Analyses of typical anorthositic rocks are shown in Table 5.
The pyroxene-rich ferrogabbro dike shows "soft" contacts with the anorthosite and is interpreted as essentially coeval. Zircons from it give a minimum age of 1087 Ma and, by comparison with other Adirondack anorthosites, its emplacement age is set at ca. 1135 Ma. The composition of the ferrogabbro is shown in table 5 where it is seen to be rich in TiO2 and P2O5. Similar rocks occur together with other Adirondack anorthosites and are interpreted as late, Fe enriched differentiates of a Fenner-type fractionation trend. It is suggested that further differentiation within these rocks can result in liquid immiscibility and the production of magnetite-ilmenite liquids.
The upper, weathered surface of the outcrop affords the best vantage point for studying the textures and mineralogy of the anorthositic rocks. In several places there can be seen excellent examples of garnet coronas of the type that are common throughout Adirondack anorthosites. These coronas are characterized by garnet rims developed around iron - titanium oxides and pyroxenes. Recently McLelland and Whitney (1977) have succeeded in describing the development of these coronas according to the following generalized reaction:
Orthopyroxene+ Plagioclase + Fe- bearing oxide + quartz= Garnet + clinopyroxene.
This reaction is similar to one proposed by de Waard (1965) but includes Fe-oxide and quartz as necessary reactant phases. The products are typomorphic of the garnet-clinopyroxene subfacies of the granulite facies (de Waard 1965). The application of various geothermometers to the phases present suggests that the P,T conditions of metamorphism were approximately 8 kb and 700±50°C respectively.

Minor marble, amphibolite, and calcsilicate rock.
Predominantly very light colored sillimanite-garnet-quartzfeldspar leucogneisses interpreted as minimum-melt granitic due to anatexis of kinzigite near Oregon dome anorthosite. Enclaves of spinel- and sillimanite-bearing metapelite are present

Entrance to Sacandaga public campsite.
On the north side. of NY Rt. 30 are quartzo-feldspathic gneisses and calcsilicates. An F1 recumbent fold trends sub-parallel to the outcrop and along its hinge line dips become vertical.

Stop 9. Pumpkin Hollow.
Large roadcuts on the east side of Rt. 30 expose excellent samples of the Sacandaga Fm. At the northern end of the outcrop typical two pyroxene-plagioclase granulites can be seen. The central part of the outcrop contains good light-colored garnet-microcline-quartz gneisses (leucogneisses). Although the weathered surfaces of these rocks are often dark due to staining, fresh samples display the typical white vs. grey color of the Sacandaga Fm. The characteristic and excellent layering of the Sacandaga Fm. is clearly developed. Note the strong flattening parallel to layering. Towards the southern end of the outcrop calc-silicates and marbles make their entrance into the section. At one fresh surface a thin layer of diopsidic marble is exposed.
At the far southern end of the roadcut there exists an exposure of the contact between the quartzo-feldspathic gneisses of the Piseco anticline and the overlying Sacandaga Fm. The hills to the south are composed of homogenous quartzo-feldspathic gneisses coring the Piseco anticline (note how ruggedly this massive unit weathers). The Sacandaga Fm. here has a northerly dip off the northern flank of the Piseco anticline and begins its descent into the southern limb of the Glens Falls syncline.
The pronounced flaggy layering in the Sacandaga Fm. is not of primary sedimentary or volcanic origin. Instead it is tectonic layering within a "straight" gneiss. Hand specimen and microscopic inspection of the light layers, particularly, reveals the existence of extreme grain size reduction and ductile flow. Long quartz rods consist of rectangular compartments of recovered quart and annealed feldspar grains occur throughout. The rock is clearly a mylonite with its mylonitic fabric parallel to compositional layering.
The chemistry of the light colored layers in the Sacandaga Fro. indicates that they are minimum melt granites. As one proceeds away from the core of the Piseco anticline, these granitic layers can be traced into less deformed sheets arid veins of coarse granite and pegmatite. In the most illustrative cases the granitic material forms anastomosing sheets that get grain size reduced and drawn into parallelism as high strain zones are approached. The Sacandaga Fm. is interpreted as an end result of this process and represents a mylonitized migmatite envelope developed in metapelites where they were intruded by AMCG granites at ca. 1150 Ma and then intensely strained during the Ottawan Orogeny at ca. 1050 Ma. This interpretation is consistent with field relationships, the presence of spinel and sillimanite restites in the leucosomes, and with the fact that similar metapelitic rocks are crosscut by ca. 1300 Ma tonalites. The latter observation makes the Sacandaga Fm. protoliths older than the ca. 1150 Ma granitic rocks in the Piseco anticline and makes an intrusive relationship obligatory despite the conformable contact at the south end of the road cut.

Southerly dipping pink, quartzofeldspathic gneisses with tectonic layering
In long roadcuts of southerly dipping pink, quartzofeldspathic gneisses with tectonic layering. The coarse grain size of the gneissic precursors can be seen in many layers.

A11: MIDDLE DEVONIAN TEMPERATE WATER BIOHERMS OF WESTERN NEW YORK STATE (EDGECLIFF MEMBER, ONONDAGA FORMATION)
Center for Earth & Environmental Sciences
DOUGLAS E. PAQUETTE
Safety and Environmental Protection Division
Brookhaven National Laboratory, Building 535A
Upton, Long Island, N.Y. 11973
The bioherms of the Edgecliff member of the Onondaga Formation are a well known feature of the geology of New York State and the Niagara Peninsula in Ontario, Canada. Over the past thirty to forty years, the Onondaga and its bioherms have been the subject of a number of studies which have greatly increased our understanding of this unit (see Bren and Ver Straeten (1994) for references).
As is the case with "reefy" limestones in general, the Edgecliff has been assumed to represent a warm, tropical, shallow water environment. However stromatoporoids and calcareous algae are rare in the Edgecliff which is unusual for Devonian reefal limestones. The absence of these organisms lead Kissling and his students (Kissling and Coughlin, 1979; Cassa and Kissling, 1982; Kissling, 1987) to interpret these bioherms as deep water structures. The absence of an obvious peritidal facies in the Onondaga was also cited as supportive of a deep water interpretation, suggesting that the shallow water facies which rimmed the basin have since been removed by erosion. More recently Wolosz (1990, 1991) has argued that shallow water facies are present, but have gone un-noticed since they do not fit the standard model for tropical carbonate peritidal facies. However, over the past fifteen years there has been increasing paleontological evidence that the "reefy" Edgecliff Member of the Onondaga Formation represents an example of Devonian temperate water deposition (Koch and Boucot, 1982; Blodgett, et al., 1988). Stromatoporoid biogeographic data and isotopic analyses which further support the temperate water hypothesis are included in this field trip guide.
The field trip will examine a series of Edgecliff bioherms, which are interpreted as representing an onshore to off-shore trend in biohermal development for this temperate water Devonian limestone.

STOP 1. Roberts Hill Reef.
NOTE: Private Property. DO NOT enter without first obtaining permission at house on north side of hill.
Roberts Hill Reef is the best known example of a Successional Mound in the Edgecliff, and has been described in detail by Wolosz (1985). This exposure allows for examination of the typical Edgecliff bioherm growth pattern of interbedded Colonial Rugosan and Favositid/crinoidal Sand Paleocommunities.
The outer edge of a central rugosan mound is exposed along the east side of a small valley which runs southwards across the hill, while the west side of the valley exposes bedded packstone flank beds with large favositid colonies. Further to the east, south and southeast a second stage of rugosan growth (Recolonization Stage of Wolosz (1985)) can be observed to cap the flank beds. This cyclic intergrowth of paleocommunities was controlled by sea-level fluctuation. Evidence for changing turbulence levels during reef growth can be directly observed at the outcrop and includes the following: 1) development of rubble apron along the northeast side of the hill which wedges out into the flank beds between the two stages of rugosan growth. This facies is dominated by the small solitary rugosan Cystiphylloides, and is interpreted as the result of an extreme shallow water stage during which the top of the mound was covered by a meadow of these small solitary rugosans. Interpretation of water depth is based on the similarity of this facies with the shallow water Cystiphylloides biostromes at Thompson's Lake Bioherm and in the Port Colbome area. 2) A rubble ring surrounding the central rugosan core and large overturned favositids in the adjoining flank beds. 3) Pods of colonial rugosan rubble at the toe of the Rugosan Recolonization Zone at the southernmost edge of the reef along the east cliff face of the hill. The large colony fragments in these rubble pods indicate elevated turbulence levels during the demise of the reef.
This reef is also tightly cemented with little observable porosity as is common for the eastern reefs of the Edgecliff.

STOP 2. Albrights Reef
NOTE: Private Property. DO NOT enter without first obtaining permission at house on north side of hill.
This exposure is a small erosional remnant of a large successional mound similar to Roberts Hill (Wolosz, 1985). It is an important exposure because it offers an excellent cross-section through the rugosan mound itself, exposes the basal contact of the mound with the underlying Edgecliff C1 facies, and allows direct observation of the successional patterns among the rugosan fauna during development of the mound.

STOP 3. North Coxsackie Reef
NOTE: Private Property. DO NOT enter without first obtaining permission at house on north-west side of intersection of Route 102 and 106 (approx. 0.7 mile south).
The North Coxsackie reef (Figures 11 and 12) is rooted in Edgecliff crinoidal grainstone/packstone- the C1 unit is absent. The main mass of the reef is a Composite Thicket/Bank reef roughly 280 meters long (north-south)by 220 meters wide (east-west) with an estimated thickness of 15 meters. Volumetrically, the Favositid/Crinoidal Sand Paleocommunity dominates this reef, having formed a bank, with beds dipping gently (5 to 12 degrees) away from the center of the structure. Interbedded with the favositid/crinoidal sand facies are two roughly 0.3 meter thick horizons of the Phaceloid Colonial Rugosan Paleocommunity - each representing a single thickening event which covered the entire mound. These thickets are dominated by Cyathocylindrium, although Cylindrophyllum and Acinophyllum are common.
A cliff along the northwestern edge of the reef exposes an approximately 6 meters thick by approximately 60 meters long Acinophyllum mound, underlain by crinoidal grainstone/-packstone. This small structure is located to the west of, and stratigraphically just above, a well defined rubble horizon exposed along the northeastern edge of the main reef, indicating that it grew on the down-current side of the mound. This mound is similar to the early Acinophyllum stage of reef growth exposed at Albrights reef, with the exception that the calci-silt-packstone matrix surrounding the corallites is more finely bioclastic, containing debris transported from the larger mound to the south.

STOP 4. Thompson's Lake Bioherm
NOTE: Private Property. DO NOT enter without first obtaining permission at house to the southwest of hill on Route 157.
This exposure has been described by Williams (1980), who divided the exposure into eleven different micro-facies, discussion of which is beyond the scope of this report. Simply put, most of the small elongate hill is made up of packstone with abundant favositid colonies. Along the roadcut two small rugosan mounds can be observed (Figure 13), underlain by roughly 2.6 meters of Edgecliff biostromal deposits, including a well developed Cystiphylloides biostrome which can be followed around the entire hill as a recessive bed. These facies are analogous to the shallow water deposits found near Port Colbome, Ontario, Canada as described in the text.
The underlying contact with the Schoharie Formation is easily observable, and represents initial shallow water deposition with grainstone as the basal Edgecliff facies.

STOP 5. Mt. Tom Reef.
The reef makes up the large hill to the south of the road.
NOTE: Private Property. DO NOTenter without first obtaining permission at house at intersection of Koenig and Mt.Tom roads. Examination of Mt.Tom #6 requires permission from farm on Koenig Road to the north of hill. Examination of Mt.Tom #2 requires permission from Mercy Hill Farm.
Paquette and Wolosz (1987) argued that three reef exposures- the Mt.Tom, Mt. Tom #2, and Mt. Tom #6 - represent the extensively eroded remains of a single large mound/bank reef. The .6 by .8 km. areal extent of this structure would make Mt. Tom both the largest exposed Edgecliff reef and the only known surface exposure of this reef type (these reefs are commonly referred to as pinnacle reefs in the subsurface).
The mound\bank nature of Mt. Tom #1 is displayed in the cliff face along the southeast side of the hill. The reef is underlain by the basal Edgecliff calcisiltite, with the base of the reef marked by thickets of Acinophyllum. Small phaceloid colonial rugosan mounds (again, mainly Acinophyllum) can be observed along the cliff near the base of the reef. These small mounds and thickets coalesced to begin the formation of the larger structure. Dominance of the initial large mound shifted between Acinophyllum and Cylindrophyllum prior to onlapping by the crinoidal sands of the favositid/crinoidal sand paleocommunity. A second mound stage made up of Cylindrophyllum thickets overlies these grainstones and packstones. In turn, the second mound stage is itself onlapped and eventually swamped by the favositid/crinoidal sand paleocommunity (exposed further back on the top of the hill, not shown in Figure 2). Overall, Mt. Tom #1 is roughly 18 m thick as preserved.
Wolosz and Paquette (1988) have interpreted this mound\bank\mound\bank pattern as catch-up\fall back cycles controlled by fluctuations in water depth above the top of the reef. It is important to note that the second mound building stage at Mt. Tom #1 does not drape the entire pre-existing structure, but is instead restricted to the top of that structure. In effect, during bank stage, the reef was a high relief platform on the sea-floor with its top within the ecologic mound building zone of the colonial rugosans. Upward growth of the reef is mainly due to the repetitive establishment of new mounds on the top of the platform. As sea-level was approached, the mound building colonial rugosans were overwhelmed by increased turbulence conditions and the mounds onlapped by encroaching crinoidal sands producing a bank stage; but with sea-level rise the mounds became re-established. This shifting between rugosan mound/thicket construction and the favositid/crinoidal sand paleocommunity has been attributed to a water turbulence controlled community succession (Wolosz, 1992b).
Following the initial mound building stage, lateral growth of Mt. Tom appears to have been due mainly to deposition of crinoidal debris flanks with occasional small mound structures (satellite mounds) growing in those flanks (see discussion of Mt. Tom #2).
Diagenetic patterns in Mt. Tom are similar to those in subsurface pinnacle reefs. The initial mound facies (base of reef) is tightly cemented, as is Mt. Tom #2; while the upper parts of the reef and Mt. Tom #6 exhibit a small primary porosity.

STOP 6. Mt. Tom #6
Mt. Tom #6 forms the low, wooded ridge to the southwest of Mt.Tom Road.
Mt. Tom #6 is a small ridge which consists mainly of bedded crinoidal grainstone/packstone. Randomly distributed small overturned favositids are common as are both solitary and phaceloid rugosans, but no evidence of mound formation is present. Topographically, Mt. Tom #6 is at the same elevation as the present top of Mt. Tom. Since the regional southwest dip of about 18 meters/kilometer (Rickard and Zenger, 1964, p.5) would not greatly alter this topographic relationship, the elevations of the Mt. Tom #6 exposure and the top of Mt. Tom were probably also equivalent at the time of deposition. However, when one observes Mt. Tom #6 from Collins Road (see map, Figure 14), the questa-like nature of this small ridge is evident, with the dip slope pointing to the north-northwest, directly away from the main mass of Mt. Tom.
Paquette and Wolosz (1987) cited this as evidence that the two exposures are parts of one reef, with Mt. Tom #6 consisting of distal flank beds. Mt. Tom reef would then be at least 0.8km. long on an northwest axis from Mt. Tom #1 to Mt. Tom #6.

STOP 7. Mt. Tom #2 Reef.
Leave cars and proceed east from the intersection. Mt. Tom #2 forms the low hill to the south of the small creek, and numerous small outcrops may be examined along the south side of the creek valley or on the hill itself. A small quarry on the northwest edge of the hillside exposes bedded Edgecliff facies, while a small rugosan mound is located just to the southeast of the quarry among the trees. In contrast to Mt. Tom #2 lies to the west of Mt. Tom #1 and is topographically roughly 18 meters below #6. Stratigraphically older beds can be examined here, with the Edgecliff/Carlisle Center contact marked by the appearance of a spring just east of the intersection of Collins and Geywittz Roads. A small quarry visible from the road exposes bedded Edgecliff with overturned colonial coral. To the southeast of this quarry is an exposure of a small colonial rugosan mound roughly 17 meters across and of indeterminate thickness. East from the quarry, along the south side of the creek, there are numerous outcrops of bedded crinoidal grainstone/packstone with abundant favositids. Small patches or lenses of colonial rugosans within the bedded packstones are common, and represent small satellite thickets or mounds which appear to range stratigraphically from near the C1/C2 contact (roughly the point at which growth of Mt. Tom #1 began), upwards to about 6 meters above that contact. The packstones surrounding these upper mounds dip away from Mt. Tom #1 at roughly 15 degrees.

B1:THE GEOLOGY OF CLARKSVILLE CAVE, ALBANY COUNTY, NEW YORK
Paul A. Rubin
909 County Rt. 2
Accord, NY 12404
SECTION A: Modification of Pre-Woodfordian Caves by Glacial Meltwater Invasion in East-Central New York
Periods of high glacial meltwater have altered some preglacial cave-passage configurations. Floodwater and fossil karst features, whose formation cannot be explained based on available water from the surrounding watershed, are found superposed on actively forming cave passages. These features may be recognized through correlation of watershed boundaries, peak-runoff observations through a cave system, the presence of anomalous in-cave and surface features, and the geomorphic interpretation of the area in question. Knowledge of minimum rates of karstification may be used to infer climatic conditions, making possible the reconstruction of the hydrology associated with deglaciation.
Clarksville Cave, situated in the hamlet of Clarksville, New York, provides an excellent example of invasion by Wisconsinan meltwater on a pre-Woodfordian cave system. Vadose development of a major part of the explored cave has occurred preferentially aslant a thrust-fault ramp, often along a calcite bed/limestone contact created by pressure solution. Other fault-related features include slickensides, extension veins, fault-bend folds, stylolites and the repeated basal Onondaga Limestone and impermeable Schoharie Formation thrust below the Onondaga Limestone stratigraphic column. An imbricate thrust east of the cave has up thrown the Esopus Shale against the Onondaga Limestone, forcing the development of an inefficient resurgence at the base level Mill Pond.
During the Wisconsinan glacial stage, subglacial meltwater formed a series of now abandoned bedrock channels and paleo-gorges that, due in part to topographic controls, found outlets along and over the flank of the Helderberg Escarpment. Some of this meltwater was pirated into Clarksville Cave where inefficient outlets resulted in the formation of higher in-cave "intermittent phreatic" levels not controlled by the thrust fault. These levels abruptly truncate and grade to lower vadose passages. The character of these upper levels, the paleo-gorge and related caves, and elevated paleo-insurgence points correlate with described alpine karst settings.
SECTION B: Flow Characteristics and Scallop-Forming Hydraulics within the Mill Pond Karst Basin, East-Central New York
This is a study of the hydrology of Clarksville Cave and the headwaters of the Onesquethaw Creek, situated in the hamlet of Clarksville, New York, specifically the Mill Pond karst basin. During most of the hydrologic year, water entering that pan of the watershed that is downstream of the Wolf Hill Dam is pirated into the Onondaga Limestone. Tracer tests and in-cave stream gaging indicate that extreme conduit conditions are present in the aquifer, with a maximum water velocity on the order of 5.3 km/hr.
It has been hypothesized that a submerged conduit must lie covered by breakdown blocks at the cave's northern terminus. Having established a known peak flow, a modified version of the Darcy-Weisbach equation was used to accurately calculate the minimum diameter of this conduit. Knowledge of the structural geology throughout the watershed, coupled with a detailed leveling survey in the cave, permitted reasonable estimates to be made for the two unknowns in the equation. A submerged conduit was subsequently opened and explored.
Scalloped cave walls are present in Perry Avenue (Fig. 3) at a key stream gaging location. Backflooding occurs behind inefficient passage constrictions a short distance downstream of, but not up to, this station. Evidence exists that documents that only long return-interval flood stages cause backflooding to this station. This situation permits a reasonable estimate of the maximum discharge and flow velocity responsible for scallop formation. Scallop wavelengths were measured below the elevation of peak floodwaters. By inputting measured values for discharge and flow velocity into published equations, it was possible to back calculate scallop Reynold's numbers that favorably correlate with measured flow velocities and discharges. A possible revision of the scallop Reynold's number is suggested when it is utilized in the determination of paleoflow velocities. It also appears that scallop wavelength is partially determined by the properties of the rock comprising the walls of the conduit.

B1:THE GEOLOGY OF CLARKSVILLE CAVE, ALBANY COUNTY, NEW YORK

STOP 1. Clarksville Cave
Turn right into parking area for June's Place restaurant. Proceed to upper parking area behind June's. Clarksville Cave is a popular caving location in the Albany area. Always cave with experienced cavers, dress warmly, wear a hardhat with a chin strap, and carry three sources of light (one preferably mounted on your helmet to free your hands for climbing). Do not attempt to pass through Brinley's Sump when there is little or no air. Under these flow conditions, the Gregory Entrance is sumped shut and a through trip is not possible. Failure to follow standard safety procedures has resulted in numerous rescues, mobilization of multiple rescue teams, ambulances, and the press.

B2: BUILDING STONES OF SCHENECTADY, NEW YORK
JANET B. HOLLOCHER
2208 Barcelona Rd.
Schenectady, NY 12309
KURT HOLLOCHER
Union College
Schenectady, NY 12308
The building stones of downtown Schenectady contain some of the best examples of rock types and medium- and small-scale geologic features that the general public can readily view. Within easy walking or driving distance are high-quality rocks of many types, some of them carefully polished and beautifully displayed. There are buildings made with igneous, sedimentary, and metamorphic rocks that include oxide rich gabbro, porphyritic granite, crossbedded sandstone, fossiliferous limestone, marble, gneiss, and partially melted migmatite. During this half-day trip, we will tour the downtown area to view the most interesting building stones, to see what minerals, fossils and other features they contain, to infer the geologic processes that formed them.
The aim of this trip is to help people to learn more about geology, just by spending a few hours in downtown Schenectady (Figure 1). Anyone who is interested in geology can observe rock types and features on his own, without a guide, and without traveling miles on rural roads, bushwhacking through woods and swamps, or stopping next to busy highways. Those who examine urban building stones can sharpen their powers of observation and learn to recognize a wide variety of rock types, minerals, features, and fossils. BRING HAND LENSES!
Each block of building stone, or each panel of facing stone, is one small window into the past. However, there are some important things to remember when looking at building stones. First, remember that all of the rocks you are looking at came from somewhere else. The geologic history that they record within them happened in another place. Second, many buildings contain rocks of several types, so as to juxtapose geologic events from different places and different times. No matter how closely adjacent stones may seem to match one another, we can not, in a strict sense, prove that they were ever connected in their original positions. However, it is a reasonable assumption that similar stones from the same building came from the same formation or body of rock, and possibly came from the same quarry. While the overall arrangement of the stones in a building has no geological meaning, we can gain knowledge about the original rock as the sum of observations made on individual stones.

B2: BUILDING STONES OF SCHENECTADY, NEW YORK

STOP 1. Nott Memorial.
Note the various building materials that comprise this structure, from foundation to roof. The foundation appears to be made of gray granodiorite. The abundant wall stones are gray lithic sandstone that may be Devonian in age, from the Catskill Delta, or Ordovician, from the Schenectady Formation. The columns are of pink granite and gray granodiorite. The light-colored cross bedded quartz sandstone on the steps is probably the Berea sandstone from Ohio.

STOP 2. Memorial Chapel.
This building, constructed after World War I, has been here long enough to demonstrate the effects of weathering on rock. The columns in front of the building are made of calcite marble. Notice that the surfaces of the marble facing the building are smooth with sharp edges. The surfaces facing away from the building are rougher and the edges more rounded, a result of chemical and mechanical weathering on the side exposed to the elements. The steps are gray granitic rock, made of quartz, biotite, and feldspar.

STOP 3. Webster House, SW comer of Union campus.
This building was once the library for the City of Schenectady. The steps and foundation are made of muscovite granite with at least one inclusion of foliated muscovite granite. The sides of the steps are made of a fossil hash limestone, composed of broken pieces of shells, crinoids, and bryozoans. The kinds of fossils and the relatively uniform grain size suggest that they were deposited in a shallow marine environment by relatively uniform currents. The columns on the front of the building are pink granite similar to that quarried on Deer Isle, Maine. The granite has a "rapakivi" texture, which consists of pink microcline phenocrysts with rims of white albite. rapakivi is a Finnish name meaning approximately "mud rock", after the crystal-bearing soil that commonly develops on rapakivi granite. Other minerals include black biotite and quartz.

STOP 4. 600 Liberty Street
This building has decorative facing stones of muscovite quartzite. This is a metamorphic rock composed mostly of quartz, and with some muscovite, tourmaline, and pyrite. Rocks similar to these are found in the Adirondacks and in New England. The original rock, or protolith, was most likely a quartz-rich sandstone or quartz conglomerate that contained some clay, iron sulfide, and probably organic matter. During metamorphism, under the influence of heat and pressure, the quartz grains in the sand recrystallized into quartzite, while the clays and associated sulfides were transformed into layers composed of muscovite, tourmaline, and pyrite.
Thanks to the varying placement of the stones, one can observe the layers from the side and also face-on. Most of the stones have been placed with the layering horizontal, so that you see contrasting layers that are relatively rich in quartz or in muscovite. Some stones are oriented with the layering vertical and parallel to the building face, so that the stones look sparkly and the long, black tourmaline crystals are easily visible on the surface.
Some of the quartzite is colored pinkish red by weathering pyrite, which leaves cube-shaped cavities behind. One can still see pyrite cubes in some of the stones. Into other cavities, quartz crystals have grown and their prismatic shapes are visible. On the southernmost section of quartzite facing, quartz veins can be seen, some containing quartz boudins - strong quartz layers around which other, weaker rock has deformed.

STOP 5. 600 Franklin Street.
This one-story modern building has a facade of sandstone that is stunningly fossiliferous. Probably from a Paleozoic shoreline environment, where rich shell beds lay near a sandy beach, this rock is full of fossils. Look for large and whole brachiopods, pelecypods, and gastropods (up to 6 cm across). Note that many of the blocks are darker (browner or redder) and more porous near their periphery. This "weathering rind" probably formed along joint surfaces through which ground water flowed. The ground water gradually dissolved away some calcite, making the rock porous with abundant fossil molds. The joints also broke the rock into slabs, which were later subdivided into blocks for building.

STOP 6. Schenectady County Office Building,
The facade of this modern building contains three types of building stone. At the Veeder Avenue entrance, the steps and low enclosing wall are made of coarse, gray granite which contains white plagioclase, pink K-feldspar, hornblende, and gray quartz.
The red facing stone around the Veeder Avenue entrance is an oxidized granite. The oxidized iron, as hematite, gives it a red color. Look closely at the quartz to see its bluish cast, an effect that is commonly produced by the presence of sub-microscopic rutile crystals that scatter blue light. The presence of blue quartz suggests a special temperature history for the rock. Titanium, in the original magma, was included as a minor dissolved impurity in quartz as it crystallized. If the pluton had cooled relatively quickly, over tens of thousands of years, titanium would have remained dissolved in the quartz. However, this pluton either cooled much more slowly, or the pluton was reheated to moderate temperatures and slowly cooled long after the pluton was solid. Over this long time at moderate temperatures (∼400°C), titanium dissolved in the quartz nucleated and grew as tiny rutile crystals.
The retaining wall and the low walls parallel to Veeder Avenue and enclosing the Albany Street entrance are made of gray diorite, a plutonic igneous rock that contains much less quartz and K-feldspar than granite, and more sodium- and calcium-rich plagioclase. This diorite contains fine-grained xenoliths, which look like dark blobs. They may be "auto-inclusions", inclusions of finer-grained (more rapidly cooled) portions of the same magma, which was later fractured and mixed with adjacent magma.

STOP 7.County Courthouse, Albany Street.
The walls next to the sidewalk are biotite granite. The dark, sparkly flecks are the mica biotite, which are the next most abundant mineral after feldspar and quartz. The steps of the Courthouse are muscovite granite, which is similar to the biotite granite but it also has shiny flakes of colorless muscovite.
The columns and pediments of the Courthouse are made of limestone. First, look at the middle pediment on the left as you face the Courthouse. Notice the layers in this rock. In the lower half of this pediment, the layers are slanted; in the upper half, the layers are horizontal. The slanted layers are called cross-beds. Inspection of the rock with a hand lens shows that it is made largely of small fossil fragments. Many of the fossil fragments are rounded, suggesting abrasion during transport in water. The fact that most of the particles are of similar size suggests deposition by relatively even currents water. These observations might lead us to interpret that this rock originated as deposits in tidal channels or deltas on a carbonate bank, such as might be found in the present day Bahamas.

TOP 8. St. Joseph's Church, Albany Street.
This brick church has four types of building stone. The lowest foundation stone is a gray-green sandstone. Notice the pattern of closely spaced horizontal lines made by cutting tools on many of the block surfaces. Notice, too, that some of the blocks have another, less regular pattern of horizontal lines or grooves, thicker than the tool-cut pattern. These are "plane beds", horizontal layers made when sand is deposited in fast-moving streams or currents. These may be Devonian sandstones from the Catskill Delta.
Capping the lower foundation stone is a lighter-colored fossiliferous limestone that contains bryozoans. The steps of the church are made of coarse-grained, gray, biotite granite. Atop the stones that flank the steps are blocks of fossil hash limestone.

STOP 9. 504 State Street.
The large panels of facing stone that cover the entryway are made of marble. Look for panels that contain large and dramatic folds that are highlighted by gray patches and layers in the white rock. The black specks and gray areas are graphite, formed by the metamorphism of organic matter that was present in the original limestone. The sparkly mineral is the brown mica, phlogopite, a magnesium-rich biotite. The elongate, colorless to light brown crystals in the marble are the mineral actinolite, an amphibole similar to hornblende. Its presence indicates that high temperatures were reached during metamorphism.
Outside the entryway, note the foundation stones composed of fossil hash limestone. Notice that this limestone is coarser - the fossil fragments are larger - than in fossil hash limestones at previous stops. Notice, too, the shapes of the fragments. Many of them are rounded, indicating that the fragments have been abraded during transport.
Around the corner on Clinton Street, look at the blocks of limestone and the orientations of the layers within them. Notice that some blocks contain slanted cross-beds. In one block, a flat-lying fossiliferous layer truncates, or cuts off, the cross-beds in a lower layer. This sedimentary feature is typical of channel fills - channels that have cut into underlying layers that are then filled in with sediment.

STOP 10. Key Bank, 436 State St.
The foundation stones on the outside of this building are made of rapakivi granite. Look closely and you will see large crystals of feldspar, much larger than the other crystals in the rock. These large crystals are called phenocrysts, and they crystallized from the slowly-cooling magma. Later, more rapid cooling caused crystallization of the smaller crystals that make up the matrix to the phenocrysts.

STOP 11. 340 State Street.
The facing stone on this building is made of a granitic migmatite that contains the minerals K-feldspar, quartz, plagioclase, and biotite. This rock is composed of two parts: a metamorphic component and an igneous component that are closely associated. The metamorphic component is a layered gneiss that is separated into blocks by dikes and other small bodies of unlayered granite and granitic pegmatite. The gneiss has the same mineralogy as the granite, and it contains fine-grained dark inclusions that look like igneous xenoliths. This evidence suggests that the gneiss was once a granite, was then metamorphosed to form the gneiss, and metamorphism reached high enough temperatures so that the rock partially melted (∼800°C). Deformation while the rock was partly liquid caused segregation of the liquid into fractures, which became the granite and pegmatite dikes when they crystallized during cooling.
Buildings were replaced after 1995.

STOP 12. 332 State St.
The base of this building is made of a fine-grained biotite granite, over which is a fossil hash limestone.
Buildings were replaced after 1995.

STOP 13. TrustCo Bank, 320 State St.
This building has columns of pink biotite granite and slabs of polished red granite. The latter is particularly interesting. It contains large, gray to white plagioclase crystals that contain concentric layers within them having slightly different appearance. The layers formed as the crystals grew while suspended in the granite liquid. Some of the pink K-feldspar crystals have rims of white albite, which is the rapakivi texture described above. The zoning and rapakivi textures indicate physical changes in the magma during growth of these crystals, changes that may have included temperature, pressure, water content, or the chemical composition of the liquid during mixing with other magma or during crystallization of the liquid.

STOP 14. Rudnick's, 308 State St.
This storefront is faced with a granitic gneiss: a metamorphosed light-pink or tan granite. If you look carefully, you will see that the rock has a weak foliation that is defined by the parallel orientation of elongated crystals, including feldspar augen. Augen formed during deformation from pre-existing large crystals in the granite protolith.

STOP 15. Fleet Bank, 306 State Street.
Although the source of this rock is unknown, it looks just like the Whiteface Mountain facies of anorthosite from the high peaks region of the Adirondacks. Anorthosite is an igneous rock composed mostly of dark- to light-gray plagioclase with small quantities of black pyroxene and perhaps a few other minerals. Undeformed Adirondack anorthosite contains large dark-gray plagioclase crystals up to 30 cm long, and commonly 10 cm long. The dark color is caused by dust-sized ilmenite that formed in the plagioclase during cooling. When the original anorthosite was deformed, the edges of the gray plagioclase, and sometimes whole crystals, recrystallized into smaller light-gray or white plagioclase crystals that are free of ilmenite dust. In some of the less deformed parts of this rock you can see nice, big dark-gray igneous plagioclase crystals, and interlocking plagioclase and pyroxene crystals that have the original igneous texture. If you look closely at the dark-gray plagioclase crystals, you may see the blue iridescence that this variety of plagioclase is famous for.

STOP 16. Olender Furniture, 260 State Street.
The front of this building is made of polished muscovite-biotite granite. The interesting thing about this rock is that, if you look closely with a hand lens, you will see occasional dull pinkish-tan crystals up to 2 mm long. These are crystals of allanite, a member of the epidote family that is extremely rich in rare earth elements and the radioactive elements uranium and thorium. Over geologic time, the uranium and thorium cause sufficient radiation damage to the allanite crystal lattice to destroy it. The result is a glass that weathers easily to the pink material you see. Fresh allanite is dark brown and shiny. This granite is probably no more radioactive than the other rocks you have seen today, it just has larger (but fewer) crystals that contain these ubiquitous radioactive elements. This rock also contains small xenoliths, or perhaps auto-inclusions, and big, white K-feldspar phenocrysts.

STOP 17. 224 State Street.
The face of this building is composed of pink biotite granite that contains several xenoliths. Besides these and the zoned feldspars, the most interesting aspect of this rock is that it contains numerous, brownish-red crystals of sphene up to 3 mm long that are shaped like elongated diamonds. The name sphene is derived from the Latin word for wedge, which these pointy crystals resemble. Sphene is useful for radiometric dating, and is one of the second author's favorite minerals.

STOP 18. Fleet Bank, 216 State St.
The facing stone of this entryway is composed of an almost black gabbro, an iron- and magnesium-rich rock that is rare as a building stone. The bulk of the rock is composed of dark-gray plagioclase, up to 5 cm long, and black clinopyroxene. These form an interlocking, igneous texture. If you look at a low angle at the highly polished surface, you will see that some patches of crystals are very shiny, like metal. If you look closely at these metallic patches, you will see that there are two different minerals present. One is more shiny and better polished. This is ilmenite which, in large concentrations, is the principle ore mineral of titanium. The other is somewhat duller and more poorly polished. This mineral is magnetite, and its poor polish is caused by its four good cleavage planes. The intersecting cleavages make numerous tiny triangular pits on the surface that are difficult to polish away. Ilmenite and magnetite both crystallized from the magma, are both oxide minerals, and are both natural semiconductors. This building also has fossil hash limestone and biotite granodiorite. The granodiorite contains phenocrysts of white feldspar.

STOP 19. Curb stone at the intersection of Mill Lane and State St.
This rock is a granitic gneiss that has a peculiar texture. Most of the mineral grains are rather small and form closely-spaced layers. The most obvious grains, however, are white feldspars that have angular or broken shapes. This is a particular kind of gneiss known as a mylonite. Mylonites are fault rocks in which fault deformation was by slow ductile flow instead of by brittle fracture. This rock was deformed enough to recrystallize the quartz and micas, but the large, strong feldspars remain intact enough to give an indication of the original grain size of the granite.

STOP 20. YMCA, on the south side facing State St.
The lower part of the building is made of highly fossiliferous limestone, in which can be seen bryozoans, crinoids, brachiopods, and gastropods. Some of the stones have layering, both horizontal plane beds and cross beds. These indicate that this rock was deposited in a near shore carbonate bank environment in which currents, possibly driven by the tides, transported and deposited the fossils.

STOP 21. Washington St. at Rotondo Park.
The stone wall at this Mohawk River overlook is composed mostly of fine-grained dolomitic limestone. The limestone is made of fine-grained, gray calcite mud, with irregular layers and patches of coarser-grained, brownish dolomite. The dolomite fills ancient worm burrows and bioturbated horizons in the rock.
In addition, the lower part of the wall on the west side contains some blocks of fossil-rich limestone that contain large brachiopods and tabulate coral. There are also some blocks of gray Schenectady Formation lithic sandstone, one of which has exposed flute casts that were formed by the swift turbidity currents that deposited the sandstones.

STOP 22. 21 Front St.
This house contains an excellent example of a red sandstone. With a hand lens you will be able to see that the rock contains abundant translucent white and pink feldspars in addition to gray glassy quartz and mica. The abundant feldspars mean that this sandstone is classified as an arkose (Figure 2), the grains for which were derived from coarse-grained igneous or metamorphic rocks, and were transported a relatively short distance prior to final sedimentation and lithification into rock. The red color strongly indicates that this sediment was originally deposited on land, which allowed oxidation of the iron to form the red hematite pigment. This rock was probably quarried from Mesozoic red beds in the Connecticut River basin or in the NewarkDelaware basin farther south.

STOP 23. First Reformed Church
This church was originally built in 1862, but was damaged by fire and rebuilt in 1948. The foundation to this church is made of highly fossiliferous limestone that contains abundant bryozoans, brachiopods, tabulate and rugose corals, crinoids, and cephalopods.
The front of the church has steps made of slate, probably from the Taconics in New York or Vermont. The pillars are made of pink granite, containing pink K-feldspar, white albite, clear gray quartz, and black mafic minerals. Several xenoliths can be seen. The coarse-grained red sandstone surrounding the doors is feldspar-rich arkose similar to that at Stop 22. The brown sandstone, which is carved into the forms of corn, grapes, wheat, pine, and oak, is a quartz sandstone in which most of the grains are glassy quartz. In both sandstones the coloring agent is hematite.
The step below the doorway on the east side near the front of the church is a different fossiliferous limestone that contains abundant gastropods up to 4 cm across. This rock also contains thin, black fragments of trilobite shells and sub-spherical ostracods (?).

STOP 24. St. Georges Episcopal Church.
In the cemetery next to this church one can see the results of differential weathering. Compare in particular the weathering of marble and red sandstone of stones of similar age.
The stone around the front door is made of fossiliferous limestone that includes beautiful examples of brachiopods, rugose coral, bryozoans, trilobite fragments, crinoids, and fine-grained rip-up clasts that were probably broken up and transported during storms. Some of the rip-up clasts contain thin layers that were probably deposited by algal mats on the floors of quiet lagoons. Most of the church is made of gray sandstone that weathers brown.

STOP 25. First Presbyterian Church, 209 Union St.
This building contains red quartz sandstone and blocks of gray sandstone, probably from the Schenectady Formation. The building next door is the Turnbull House. It is made of a red quartz sandstone that has numerous peculiar pockmarks up to 4 mm across. Many of the pockmarks have a rhombic (diamond) shape that is reminiscent of the crystal form of calcite. Calcite was probably the first cement in this rock, which was then followed by a more durable cement such as quartz. When the sandstone blocks were exposed to the weather, the soluble calcite gradually dissolved, and the sand grains which the calcite held in place fell out, leaving the pits.
The steps of this building are made of red arkose, in which can be seen numerous black grains which are sand-size grains of the fine-grained metamorphic rocks slate and phyllite. The presence of both feldspars and low-grade metamorphic rock fragments indicates a nearby source area for the sand that was made up of igneous and low-grade metamorphic rock.

STOP 26. 220 Union St., Van Antwerp house
This old house has a variety of different kinds of slate on its roof. The colors of the slates include black, red, gray, green, and purple. The different shapes, thicknesses, and edge treatments clearly show that the slates had different sources, and were probably periodically replaced to make repairs. The rusty-weathering slates are probably from Pennsylvania, whereas the others are probably from the Taconics in Vermont or New York.

STOP 27. 108 Union, the old Schenectady Court House.
The steps are made of gray sandstone that has interesting parallel grooves on their sides. These grooves are formed as the plane beds in the sandstone weather out at different rates because of different grain sizes or different cements in alternating layers. The blocks to the sides of the steps are made of fossiliferous limestone that contains tabulate and rugose corals, brachiopods, and other fossils. An excellent tabulate coral can be seen to the left of the steps, and a large cephalopod fragment can be seen just to the right of the steps.

The facing stone beneath the windows is marble. This marble is particularly interesting because it contains stylolites- very wiggly, sub-parallel sets of black lines in the rock. Stylolites form as fractures or other surfaces in the rock, along which water flowed during burial or low-grade metamorphism. The water dissolved some of the calcite, and left the dark insoluble material behind. Dissolution does not form a flat surface, but rather develops interdigitating calcite fingers on either side of the solution surface. This is what makes the stylolites so irregular. The fingers point in the direction of the maximum compressive stress that was acting on the rock during stylolite formation. This building also has muscovite-biotite granite facing some portions, and blocks of very fine-grained fossil hash limestone with visible bedding.

STOP 29. 225 State St.
The facing below the windows of this building is black slate. The surface of the slate is the natural texture that formed when the slate was split along its excellent cleavage. The cleavage of slate is caused by the parallel alignment of muscovite and chlorite, which themselves have an excellent mineral cleavage. The sections of the building between the windows are faced with biotite granite, which contains rare, large feldspar phenocrysts.

STOP 30. Mr. James Salon, 249 State St.
The beautiful polished green stone on the outside of this building is a chlorite schist, rare in building stone because it is quite soft and hard to polish. If you look closely, you will see dark red garnets up to 4 mm across in this lovely rock. The most striking thing about this rock is its wavy "grain". The principal grain is a strong foliation of parallel-aligned chlorite crystals. This foliation was developed by deformation during metamorphism. At the time it was formed, this foliation was probably quite planar. The rock was later deformed twice to form two sets of small "crenulation" folds that are similar in size, shape, and appearance to the corrugated paper of a cardboard box. This rock therefore gives clear evidence of three episodes of deformation during metamorphism. Different episodes of deformation probably indicate different episodes of the mountain building event that caused the metamorphism.

STOP 31. Schenectady Federal Savings, 251 State St.
This entryway is faced with slabs of spectacular red granitic migmatite. The visible minerals include pink K-feldspar, white plagioclase, glassy-clear gray quartz, and black biotite. As described above, migmatite means "mixed rock" in which some parts appear to be metamorphic rock and others appear to be igneous. The layered portions of this rock are gneisses that have been highly metamorphosed and deformed. The igneous rocks include the entire range from fine grained granite to granitic pegmatite (very coarse-grained). In some places gneissic layers or granitic dikes have been offset by small shear zones (very local and short faults), that formed when the rock was hot, ductile, and probably partly liquid. Some of the granite dikes are obviously intrusive and crosscut layering or other dikes, but some appear to have formed in place by the partial melting of the metamorphic portions. On the polished surface one can see metallic gray and metallic yellow minerals, which are iron oxides and pyrite, respectively.

This building has polished facing stone that looks identical to the dark gabbro at Stop 18, only more fine-grained. The Photo Lab, at 273 State St. has a few small slabs of gray quartz monzonite porphyry on the lower part of the foundation.

STOP 33. Wall Street
At the intersection of State Street and Erie Boulevard. The lower part of the wall facing Erie Boulevard is composed of fossiliferous limestone. Many of the features that can be seen here are illustrated and explained in Figure 4. Some layers in the rock are composed of very fine-grained carbonate mud that contains few fossils. This may have been deposited in a quiet, possibly hypersaline lagoon environment. The coarse-grained layers that are interbedded with the carbonate mud are made mostly of whole and broken fossils and chunks of rock that look like the carbonate mud. These were probably formed by masses of water that were forced over the beach area into the lagoon during severe storms. The fast-moving, turbulent water carried fossils from the near offshore and beach environments into the lagoon where they were deposited as the currents slowed. In some cases the storm surge currents broke up lithified sediments into smaller stones, which were transported and deposited with the fossils as "rip-up clasts". The storm surge deposits are typically coarse-grained on the bottom and grade to finer-grained on top. Using this rule, you can see that some of the blocks are upside-down from their original orientation. Fossils visible here include gastropods, brachiopods, and corals. Red sandstone and fine-grained fossil hash are also present in this wall.

STOP 34. 401 State St.
The facing stone on the outside of this building is an almost black diabase, a rock of basaltic composition having a grain size and texture intermediate between that of gabbro and basalt, but having a similar chemical and mineral composition. It is formed in small plutons that cool relatively quickly (in ˜1 to 100 years), and in the centers of thick lava flows and lava lakes. This rock contains long, lath-shaped plagioclase crystals that enclose black pyroxenes and metallic iron-titanium oxides. The textures are best seen by looking at a low angle at light reflected off the polished surface.

STOP 35. Center City and CVS, 433 State St.
The facing stone here is composed of a "hypersolvus" granite. The granites we have seen previously have had discrete crystals of K-feldspar (pink or white) and plagioclase (usually white in granite, with twinning). This granite has only one feldspar with a composition intermediate between plagioclase and K-feldspar. During cooling, this intermediate feldspar composition became unstable and unmixed into very thin, alternating layers of K-feldspar and plagioclase. The unmixed feldspar is known as perthite. If you look closely with a hand lens you will see the alternating, irregular layers of unmixed plagioclase and K-feldspar in the feldspar crystals. Perthite only forms in slowly cooled rocks. If the rock had cooled quickly, it would still have only a single feldspar.

STOP 36. Jay Street pedestrian mall.
Some stores have very antique, green serpentinite, and green to maroon to brown altered serpentinite. The original material for both was probably ultramafic rock, such as a dunite or peridotite, which may have been part of the deep oceanic crust or upper mantle. During metamorphism, the rock was infiltrated by aqueous fluids that turned anhydrous olivine and pyroxene into water-bearing serpentine, talc, and amphiboles, and deposited silica and white calcite. Deformation during metamorphism shattered the rock mass, forming irregular blocks and veins. The altered serpentinite formed when later circulation of oxygen-rich water through the rock caused some of the iron in the silicates to turn to hematite, staining parts of the rock red.

STOP 37. City Hall.
This building is among the most splendid in downtown Schenectady, and is a fitting location for the end of the trip. The steps are made out of gray muscovite granite, similar to that found in many other buildings we have seen.
The columns are made of white Vermont marble. These columns show especially well the effects of weathering, similar to that seen on the columns of Memorial Hall on the Union College campus (Stop 2). The side of the columns facing the elements are rather rough and worn-looking. The side of the columns facing the building is contrastingly smooth with sharp edges to the carved flutes. The softness, excellent cleavage, and solubility of calcite in the marble is what makes it so susceptible to weathering.
The historical placards on the front of the building are made of altered serpentinite, similar to that seen along Jay St. at Stop 36.

B3: FLUVIAL GEOMORPHOLOGY OF THE PLOTTERKILL PRESERVE
Donald T. Rodbell and Paul S. Hays
Union college
The stability of hill slopes reflects a delicate balance between the driving and resisting forces on a landscape (Ritter et al., 1995). Driving forces on a hill slope are those that increase shear stress and promote mass wasting whereas resisting forces are those that contribute to the shear strength of the materials that compose a hill slope (Table 1). Because the factors listed in Table 1 change with time, the degree of hill slope stability is transient and episodes of pronounced hill slope instability have been recognized in the geologic record (e.g. Reneau et al., 1990). For example, rapid fluvial downcutting in response to climate change and/or a lowering of local base level may destabilize hill slopes by eroding the toes of slopes and thereby removing their lateral support. This example of linked geomorphic systems is well illustrated in the Plotterkill Preserve. The Plotterkill Preserve is located ca. 10 km northwest of Schenectady, NY. The Preserve is underlain by the Schenectady Formation (Ordovician), which is composed of shale and beds of sandstone (greywacke) and represents flysch deposition derived from erosion of the Taconic island arc (see Hollocher, this volume; Kidd et al., this volume). Surficial deposits include glacial drift, talus and colluvium, and fluvial sand and gravel. The Plotterkill, which heads in the Helderburg Hills, is a tributary to the Mohawk River and has deeply incised into the Schenectady Formation and the overlying mantle of glacial drift. Where the Plotterkill incised into the Schenectady Formation, near-vertical escarpments of up to ca. 25 m occur. In contrast, in at least one locality where the Plotterkill has cut through a locally thick deposit of glacial drift, a large (5600 m2) complex rotational slump-earth flow occurred and remains active today.

B3: FLUVIAL GEOMORPHOLOGY OF THE PLOTTERKILL PRESERVE

STOP 1. Plotterkill Preserve
From here we will spend several hours walking along the Plotterkill; the trails are well marked but some are quite steep.
We will begin by walking down the trail to the Plotterkill (Fig. 4). As you approach the valley floor (ca. 8 minutes) and before you reach the alluvial fan (Fig. 4) you will notice the curved trunks of some trees on the hillside to your left. Tilted trunks are a good indication that soil creep is active on the hillside
When you reach the relatively flat valley floor, you will be standing on an alluvial fan (Fig. 4) which is graded to a level that is much higher than the modem Plotterkill. As you continue down the axis of the fan you will cross two scarps, which demarcate distinct terrace levels cut onto the toe of the alluvial fan by the Plotterkill. The trail turns to follow the south side of the Plotterkill and enters the downvalley end of an abandoned channel of the Plotterkill. Well preserved terraces can be seen on either side of this paleochannel. At the downvalley end of the abandoned channel, there is a good exposure into one of the prominent terraces in this part of the valley. This exposure reveals ca. 1-2 m of a very poorly sorted deposit of sand, gravel, and angular boulders up to 70 cm long. Clasts in these deposits are angular and were derived locally from the sandstone units of the Schenectady Formation. These clasts show a pronounced imbrication in which their a-b planes are inclined upstream, reflecting fluvial transport. In addition, one can observe that the modem Plotterkill flows on a beveled surface of Schenectady Formation shale. In places this surface is mantled by ca. 1 m or more of coarse and poorly sorted alluvium, which is very similar to the material that makes up the deposits that underlie the terrace surface.
Follow the paleochannel until the trail crosses the Plotterkill. You will see the large landslide to your left (south). The upvalley end of the paleochannel corresponds precisely with the downvalley end of the landslide. It is likely that initial movement of the slide forced the course of the Plotterkill to the north until it avulsed its channel, thus forming the paleochannel. Subsequent fluvial incision into the slide material and southward migration of the cut bank of the Plotterkill has isolated the inlet to the paleochannel.
Continue up the bed of the Plotterkill. Watch your step! On the south side of the Plotterkill, approximately 75 m upstream from the landslide is an excellent example of a flight of fluvial terraces (Fig. 2). Here, three distinct terraces can be differentiated on the basis of elevation. In addition, exposures into the alluvium that underlies the terrace surface can be seen. In several locations one can see clearly that the alluvium rests unconformably on a beveled surface which has been cut onto the shales of the Schenectady Formation. This surface is a rock cut terrace or a strath (Ritter et al., 1995) and is overlain by alluvium. The observation of a planar erosional surface that mirrors the terrace tread and which is overlain by alluvium the thickness of which does not exceed the normal scouring depth of the river meets the criteria for designating a terrace an erosional or strath terrace (Mackin, 1937). The presence of strath terraces suggests that the Plotterkill has been incising its channel progressively and that this incision was punctuated by periods of stream equilibrium during which time the Plotterkill laterally eroded the underlying Schenectady Formation. Step-wise incision may have been caused by episodic increases in stream power, decreases in sediment yield to the stream, decreases in local base level, or a combination of these three factors.
Return to the base of the landslide. Standing here, one can clearly see the abundant exotic lithologies that make up the material composing the landslide (Table 2). This material is till and its prevalence in this part of the valley suggests that hill slope instability at this particular point in the valley is due, in part, to the influence of lithology on hill slope stability.
Walk up the slide. The slide surface can be divided into an upper and lower half (Fig. 3). The lower part of the slide is devoid of vegetation except for several small tree islands; these may be remnants of a continuous vegetated surface. Tree ring studies suggest that this surface is more than 30 years old. This part of the slide is continuously eroding into the Plotterkill and during times of high water tables, springs develop in the uppermost part of the lower half of the slide. These springs probably reflect ground water flow along shear planes that underlie the upper half of the slide. Saturation of the lower half of the slide is responsible for this nearly continuous earth flow. The upper half of the slide is probably dominated by rotational slide (slump) activity as is evidenced by transverse tensional cracks, minor scarps and rotated segments. The uppermost part of this part of the slide is characterized by a prominent near-vertical scarp.
An array of stakes (steel rebars) have been placed on the surface of the landslide and surveyed precisely using an electronic distance meter in April, 1995. We plan to monitor the movement of the landslide annually.

STOP 2. Gravel pit on north side of road
(pit is owned by Scotia Sand and Stone Company- 518-346-5749)
This gravel pit provides excellent exposures of the Scotia Delta (see Wall and LaFleur, this volume) that prograded eastward into Glacial Lake Albany. We are stopping here to briefly see the unequivocal evidence that these exposures reveal for higher local base levels ca. 12-13 ka. The elevation of the foreset-topset transition here (88 m) can be used to estimate of the surface of Glacial Lake Albany ca. 12.5 ka (see Wall and LaFleur, this volume) and hence of local base level at that time. Progressive and step-wise lowering of local base level to the modern elevation of the Mohawk River at this point of the Mohawk Valley (67 m) may have been responsible for episodic incision by the Plotterkill and other creeks in the region (e.g., Washout Creek, Fig. 1).

STOP 3. Scotia Delta
Here we can see a lower level of the Scotia delta to the right (south) of Rt. 5N. There are at least 3 levels of the Scotia delta in this part of the Mohawk Valley. The elevations of these levels are 90 m, 85 m, and 70 m.

B4: SEQUENCE STRATIGRAPHY OF PLATFORM CARBONATES: DEVONIAN LIMESTONES OF JOHN BOYD THACHER STATE PARK, SOUTHWEST OF ALBANY, NY
GERALD M. FRIEDMAN
Brooklyn College and Graduate School of the City University of New York,
Brooklyn, NY 11210
Northeastern Science Foundation affiliated with Brooklyn College
Rensselaer Center of Applied Geology,
15 Third Street, P.O. Box 746, Troy, NY 12181-0746
The Lower Devonian strata that crop out on the Helderberg Escarpment illustrate the characteristics of marine platform parasequences in carbonate rocks. In the hierarchy of stratigraphic units, parasequences are a relatively conformable succession of genetically related strata bounded by surfaces of erosion. The parasequences exposed in this escarpment, which include stromatoporoid reefs, stromatolites, and lithified lime mud (micrite) show regressive facies separated by unconformities representing transgressive episodes. The lowermost part of the section exhibits classical karst-generated solution collapse breccia of the kind that hosts oils and gas in the subsurface. The Middle Devonian Onondaga facies at this site are full of coral-reef debris. In the subsurface, Onondaga reefs form gas reservoirs and now serve as reservoirs for gas storage. Sir Charles Lyell visited this classic site, part of the Helderberg Mountains, in 1841 and a monument commemorates his visit and that of Sir William Logan, James Hall, Amos Eaton, and others of the heroic age of Geology.
No road log, only the one stop at Indian Ladder

B5: LOWER AND MIDDLE DEVONIAN FORELAND BASIN FILL IN THE CATSKILL FRONT - STRATIGRAPHIC SYNTHESIS, SEQUENCE STRATIGRAPHY, AND THE ACADIAN OROGENY
CHARLES A. VER STRAETEN AND CARLTON E. BRETT
Modern stratigraphic study has come to be increasingly based on high resolution subdivision of the sedimentary record through detailed event and cyclic analysis. The recognition and correlation of unique single event horizons (e.g., altered volcanic ashes, shell marker beds, faunal epiboles and immigration events) and genetically-related depositional sequences permits microstratigraphic subdivision of the rock record at a finer scale than is possible through classical methods of bio- and lithostratigraphy. "Layer cake" stratigraphy, once the bane of stratigraphic thought, has again emerged in modified form through the application of "Event" (Kauffinan., 1988) and "Sequence Stratigraphic" (Van Wagoner et al., 1988) methods.
The construction of a refined microstratigraphic framework of strata permits detailed analysis of the timing and nature of events in the rock record. Short term dynamics in the history of a basin are recorded by: sharp transitions between intrabasinal and extra-basinal sedimentation; clustered volcanogenic strata; condensed beds and minor unconformities; abrupt changes in faunas and short-term incursions of exotic faunas; cyclic sedimentation; and eustatic- and tectonic-controlled changes in relative sea level. A detailed, correlatable framework of large and small scale events helps unravel the history of a sedimentary basin.
The late Early and Middle Devonian was a very dynamic time on the margin of the Eastern Interior of North America. A continent-continent collision, subsequent subsidence and infilling of an adjacent sedimentary foreland basin, and the evolution and migration of major faunas are recorded in the rocks of the Catskill Front in eastern New York State. The interaction of tectonically-induced flexure of the foreland basin and changes in eustatic sea level had a profound influence on the Northern Appalachian Basin at that time. Alternating tectonically active and quiescent stages of the Acadian Orogen (Acadian "Tectophases" of Ettensohn, 1985) resulted in major periodic alterations of subsidence and uplift, sedimentary style, faunas, and paleoecology. Superimposed over the tectonic influences are apparent changes in eustatic sea level (e.g., Johnson et al., 1985). As a result, the upper Lower and Middle Devonian foreland basin fill of New York is a complex succession of tabular to distinctly wedge-shaped bodies of carbonates and siliciclastics, shifting depocenters and basin centers, and marked unconformities.
This paper and field trip will examine the sedimentary record of the upper Lower and Middle Devonian rocks in the Catskill Front (see Figure 1). In addition to a review of member- and formation-level stratigraphy, the authors will present: 1) important new details and interpretations of strata of the Tristates Group, the Onondaga Formation, and the lower part of the Hamilton Group; 2) a discussion of the major and minor unconformities within the study interval; 3) the sequence stratigraphic framework for the upper Lower and Middle Devonian in New York State; and 4) stratigraphic trends and their implications for the evolution of the Northern Appalachian Basin and the Acadian Orogeny.

B5: LOWER AND MIDDLE DEVONIAN FORELAND BASIN FILL IN THE CATSKILL FRONT - STRATIGRAPHIC SYNTHESIS, SEQUENCE STRATIGRAPHY, AND THE ACADIAN OROGENY

Observe west wall of Mohawk Valley in distance on right

View of Helderberg Escarpment
View of Helderberg Escarpment, capped by Lower and Middle Devonian strata. straight
ahead.

Proceed through the Albany Pine Plain
Proceed through the Albany Pine Plain, on late-glacial windblown sand dunes near the northwest shore of glacial Lake Albany.

Highway continues through the Albany Pine Plain
Note vegetated sand dunes along Thruway.

Taconic Mountains visible in distance ahead
Remnants of Ordovician overthrusted highlands of the Taconic Orogeny.

Cross over Normanskill Gorge
Cross over Normanskill Gorge, near type section of Ordovician Normanskill Group.

Views of Helderberg Escarpment to right for next 17.5 mi.

Roadcuts in flysch-type sediments
Roadcuts in flysch-type sediments of Ordovician Austin Glen Formation (Normanskill Group) along NYS Thruway for next 15 mi.

Catskill Mountains visible ahead
Catskill Mountains, middle to Upper Devonian strata, visible ahead. Helderberg Escarpment on right, with limestone outcropping near crest of ridge.

Classic outcrop of "Dinosaur Leather" sole marks
Classic outcrop of "Dinosaur Leather", sole marks on base of Austin Glen Fm. turbidite bed visible 1.0 mi. north of Coxsackie exit along west side of N.Y. Rt. 9W.

Outcrops of Lower Devonian Kalkberg Limestone
Outcrops of Lower Devonian Kalkberg Limestone (Helderberg Group) visible on both sides of Thruway as you rise up onto the Helderberg-Kalkberg Escarpment. Exposures of Helderberg Group (Manlius, Coeymans, Kalkberg, New Scotland, and Becraft. Fms., in ascending order) for next 2.5 mi.

Lower Devonian Esopus Formation
Long outcrop of middle part of Lower Devonian Esopus Formation (dark shale; Tristates Group) on right

Strongly-dipping outcrop on left
Strongly-dipping outcrop of Lower Devonian Glenerie Formation? (Tristates Group) on left.

New Scotland and Becraft Formations on left.

Esopus Shale on left.

Schoharie Formation on right; note dark band.

Low anticline on right.

Cherty Onondaga Formation (limestone)
Cherty Onondaga Formation (limestone) on both sides of I-87 for next 0.4 mi.

Cuts in Helderberg Group
Cuts in Helderberg Group (Kalkberg, New Scotland, and Becraft Fms.) for next 3.0 mi.

New Scotland and Becraft Limestones along exit.
Note additional outcrops of New Scotland and Becraft Limestones along exit.

View of Catskill Mountains/Catskill Escarpment
View of Catskill Mountains/Catskill Escarpment in the distance to right.

New Scotland Limestone to left.

New Scotland, then Kalkberg Formations on right.

Bear right onto entrance ramp for NY Rt. 23 West
Exit ramp to left (east) shows angular unconformity of Ordovician Austin Glen Formation with uppermost Silurian Rondout Group; outcrop continues through Lower Devonian Manlius, Coeymans, Kalkberg, and lower part of the New Scotland formations. Faulted section along right side of entrance ramp repeats Manlius, Coeymans, and Kalkberg Formations.

Helderberg Group Limestones
Merge with Rte, 23; observe outcrops of Helderberg Group Limestones to right and left. For detailed discussion of structure of rocks along Rt. 23, see Marshak, 1990.

Crest of anticlinal structure in road cuts.

Esopus Shale on right.
Bridge over Catskill Creek; note high outcrop of Esopus Shale on right.

STOP 1A (Optional). Wallbridge Unconformity in Catskill Creek at Austin Glen.
To get to Optional Stop 1, walk back along Rt. 23 to bridge and walk down to creek along side of bridge. Turn right at bank of Catskill Creek and follow around to the natural dam in creek south of the bridge.
The natural dam at the mouth of Austin Glen is formed by the resistant base of the Lower Devonian Glenerie Limestone, underlain successively by limestones of the Port Ewen and Alsen Formations at the top of the Lower Devonian Helderberg Group. The basal bed of the Glenerie Formation is sand-rich, and features a prominent zone of reworked phosphate pebbles at its base. This phosphatic lag immediately overlies a prominent disconformity, the Wallbridge Unconformity (Sloss, 1963), which is one of six major unconformities in the Phanerozoic of North America. To the north and west, into central to western New York, this unconformity overlies progressively older rocks, as old as Late Silurian in western New York. South of Catskill the unconformity overlies progressively younger rocks in the upper part of the Port Ewen and Port Jervis Formations. In the Tristates area of southeastern New York, near Port Jervis, the succession from the Port Jervis Formation into the overlying Glenerie Formation is continuous and conformable (Rickard, 1975).
Downstream of the natural dam Catskill Creek runs through a gorge (Austin Glen) of the New Scotland and lower limestones of the Helderberg Group. The lower part of the gorge is the type section for the Ordovician Austin Glen Formation, seen previously on this trip in outcrops along the New York State Thruway. Upstream of the natural dam and the Rt. 23 bridge a high cliff of Esopus Shale is visible. Return to the anticlinal outcrop adjacent to the vehicles.

STOP 1B. Esopus, Schoharie, and Onondaga Formations.
Cuts on north side of N.Y. Rt. 23, west of bridge over Catskill Creek.
Highway cuts along Rt. 23 expose the upper part of the Esopus Formation, a complete section of the Schoharie Formation (unnamed lower, Aquetuck, and Saugerties Members), and the base of the Edgecliff Member of the Onondaga Formation in an antiformal fold west of Catskill Creek. The lower part of the exposure displays dark, rust-spotted, blocky-weathering silty shales of the Esopus Formation (Upper part of Depositional Sequence 2 of this paper). Along Rt. 23 the Esopus Shale is capped by a distinctive, 6.8 m-thick laminated unit that forms a distinctive marker at the base of the upper member of the formation. At Catskill the laminated unit is abruptly overlain by the Schoharie Formation; at Kingston, however, the top of the laminated unit underlies the Esopus-Schoharie contact by 22.5 m. The Esopus and Schoharie Formations thin laterally between Kingston and Catskill; however, the absence of upper Esopus strata above the laminated unit at Catskill appears dominantly to be associated with erosional truncation at a sequence-bounding unconformity below the Schoharie Formation (= base of Depositional Sequence 2 of this paper).
The sub-Schoharie unconformity at the base of Depositional Sequence 2 is marked by a sharp lithologic change and abundant glauconite, phosphate pebbles, fish bone material, and scattered white vein quartz pebbles. Five meters of calcareous, bioturbated argillaceous siltstone to silty mudstone of the lower unnamed member (formerly Carlisle Center Formation) overlie the contact. This contrasts sharply with up to 44 m of the unnamed member at Kingston. A 60 cm-thick, dark to black, rusty weathering, calcareous to cherty bed ("black bed" of Oliver et al., 1962) occurs near the middle of the member at both Catskill and Kingston. Glauconite and scattered quartz pebbles, apparently mixed downward from above by burrowing organisms, occur again in the upper part of the unnamed member at and below a lesser unconformity (= surface of maximum starvation in sequence stratigraphy terminology) at the base of the Aquetuck Member.
The Aquetuck Member along Rt. 23 (∼12.7 m-thick) is characterized by fine-grained, buff- to olive-banded, cherty and siliceous to calcareous shales. An interval of interbedded olive and dark gray strata 2.6-5.2 m above the member base represent the most basinal conditions in the Schoharie Formation. This interval at Kingston is represented by ∼3.25 m of dark, blocky-weathering, calcareous shale and is correlative with a widespread interval of dark gray to black shale in the middle of the Needmore Formation in central Pennsylvania (see body of paper). Carbonate content increases and the siliceous aspect of the strata decreases through the upper part of the Aquetuck Member at Catskill. The lower part of the member is unfossiliferous; small brachiopods and other forms appear in the upper part of the member, and diversify and increase in abundance upward through the overlying Saugerties Member.
The contact with the Saugerties Member is gradational and is placed at the lowest continuous, light-weathering limestone band. Nine meters of fossiliferous, interbedded buff calcareous shales and light-colored limestones comprise the Saugerties Member at Catskill. The lowest strata of the Onondaga Formation (Edgecliff Member) are exposed near the west end of the outcrop.

Outcrops of Union Springs and Mount Marion Formations on the Hoogeberg Ridge to right.

Outcrops of Esopus to left along Thruway.

Outcrops of Schoharie FormationPlacemark
Outcrops of Schoharie Formation on left and right; note prominent cleavage.

Fine brown glacial sands exposed on right
Fine brown glacial sands exposed on right (possible shoreline sands of glacial Lake Albany?).

Bridge over Kaaterskill Creek
Falls over Ordovician Austin Glen Formation on left.

Steeply-dipping Onondaga Formation on right.

Moorehouse, Nedrow and Edgecliff Members
Outcrop of Moorehouse and underlying Nedrow and Edgecliff Members of the Onondaga Limestone on left.

STOP 2. Port Ewen, Glenerie, and Esopus Formations
Port Ewen, Glenerie, and Esopus Formations, including the Wallbridge Unconformity.
Abandoned exit of New York State Thruway at N.Y. Rt. 23A. The lower and middle parts of the outcrop are accessible; the upper part of the outcrop is along the New York State Thruway and can only be observed with written permission of the Thruway Authority.
This Lower Devonian outcrop exposes uppermost strata of the Helderberg Group, the Wallbridge Unconformity, the Oriskany-equivalent Glenerie Limestone, and the lower part of the Esopus Shale. The exposure extends southward ∼300 m along the New York State Thruway, where middle and upper Esopus strata are overlain by more calcareous strata of the Schoharie Formation.
The Wallbridge Unconformity, one of six major North American Phanerozoic unconformities (Sloss, 1963) caps argillaceous limestones of the Port Ewen Formation as seen at Optional Stop 1A. The unconformity is marked by a thin ( ∼10 cm-thick) phosphate pebble-rich conglomeratic lag at the base of the Glenerie Formation. This bed lies at the base of Sloss' (1963) Kaskaskia Supersequence, which extends from the upper Lower Devonian through the Mississippian Period, and marks the base of Depositional Sequence 1 of this paper. The Glenerie Formation at Rt. 23A (3.5 m-thick) consists of relatively fine-grained, fossiliferous, drab brown limestones and dark gray cherts. Oriskany-age brachiopods are visible in cross-section in some limestone beds; the highly diverse and abundant fauna known from the Glenerie Limestone locally, however, appears absent at this outcrop.
The limestones and cherts of the Glenerie Formation are gradationally overlain by strata of the Esopus Formation at Stop 2. The lower member of the Esopus, as defined herein, consist of a tripartite subdivision of strata: 1) a lower interval of interbedded, thin siltstones, cherts, shales, and K-bentonites. This interval includes the Sprout Brook Bentonites of Ver Straeten (1992b, in review; also Ver Straeten et al., 1993), which at this outcrop consist of up to 15 thin, altered volcanic ash layers; 2) a middle subunit of dark gray to black, banded shale with scattered medium-size (∼ 10-20 cm), dark blue-gray calcareous-phosphatic concretions; and 3) an overlying coarsening-up interval of medium dark gray silty shales to buff-gray- weathering, slightly calcareous siltstones. Small brachiopods (Atlanticocoelia and/or Leptocoelia) and other uncommon fossils occur in the upper subunit, with scattered glauconite.
The lower submember (∼6.6m-thick) of the member is highly deformed at this outcrop; disharmonic folds, shear zones, and prominent fractures and cleavage are associated by Marshak (1990) with movement of a detachment fault between the Glenerie and Esopus Formations. Bentonite beds along the outcrop pinch and swell between more resistant beds and form horizons along which faults slide. The overlying middle dark gray-black shale subunit (2.0 m-thick) in the upper part of the cliff shows prominent slaty cleavage. Subunit 3 of the lower member of the Esopus Formation along Rt. 23A totals 4.0 m in thickness; its capping buff-gray siltstone bed forms a prominent ledge around the corner from the anticlinal exposure.
The overlying middle and upper members of the Esopus Formation extend southward along the outcrop and consist of rusty, dark gray silty mudstones to argillaceous siltstones that total over 40 m in thickness. The upper member of the Esopus, unlike the previous stop, consists of the laminated unit and ∼2.9 m of strongly Zoophycos-churned siltstones to fine sandstones. The base of the Schoharie Formation is marked by a prominent glauconite-rich bed with quartz pebbles. The overlying unnamed member of the Schoharie Formation is 9.2 m-thick along the Thruway cut and shows distinctive banding, as does the overlying Aquetuck Member (10.7+ m exposed; thicknesses for the Schoharie Formation reinterpreted from Johnsen, 1957). This banding may be related to Milankovitch cycles similar to those reported from Cretaceous and other age rocks (see discussion of Sequence DS3 in main body of paper).
The basal Glenerie phosphate pebble bed marks initial transgression during deposition of the first post-Wallbridge depositional sequence (=Sequence DS1 of this paper). Continued transgression coupled with the onset of tectonically-induced foreland basin subsidence (Acadian Tectophase I) marks the change into the overlying Esopus Formation. Shallowing and siliciclastic progradation through the upper part of the Esopus Formation is truncated by apparent erosion of upper Esopus strata (see discussion above) below an unconformity at the base of the Schoharie Formation (=base of Sequence DS2 of this paper).

STOP 3A. Schoharie and Onondaga Formations.
Walk carefully back along Rt. 23A to bridge over the Thruway. Highway cuts along NYS Thruway and NY Rt. 23A visible from Rt. 23A bridge. Access to exposures along thruway only through written permission of the Thruway Authority.
Highway cuts along Rt. 23 and the Thruway show extensive exposures of the Lower Devonian Schoharie and lower part of the Middle Devonian Onondaga Formations. Buff-orange, brown, and gray colors characterize the Schoharie Formation along the exposure. Light-weathering limestones, with common yellowish-weathering cherts, are typical of the Onondaga Formation. Very long exposures of the Schoharie are visible along the Thruway to the north. To the left, immediately north of the bridge, a darker, banded interval is notable in the lower part of the exposure. This interval of siliceous shales in the lower part of the Aquetuck Member (seen at Stop 1) is correlatable to a calcareous shale interval at the same position at Kingston; as previously noted, it is also recognized in the middle part of the Needmore Formation in Pennsylvania (see body of paper). Overlying strata on the northwest side of the bridge belong dominantly to the Aquetuck Member.
On the opposite side of the highway north of the bridge, alternating bands on argillaceous, buff-weathering limestones and purer, more calcareous limestone layers characterize the Saugerties Member of the Schoharie Formation. Overlying coarse, crinoid-rich, non-cherty to chert-rich limestones represent the Edgecliff Member of the Onondaga Formation.
Walk back to intersection of Rt. 23A and Old Kings Rd.

STOP 3B. Schoharie and Onondaga Formations.
Cuts along N.Y. Rte 23A at and near its intersection with Kings Highway, ∼0.0-0.3 mi. west of the bridge over the New York State Thruway.
Outcrops to the east and west of and along Old Kings Road on the south side of Rt. 23A expose argillaceous limestones of the upper part of the Schoharie Formation (Aquetuck and Saugerties Members) and a thick section of limestones of the Onondaga Formation (∼44-m thick; Edgecliff, Nedrow and Moorehouse Members). The Schoharie-Onondaga contact is exposed on the east side of Old Kings Road, south of Rt. 23A. Buff- and light gray-weathering limestones with thin quartz sand stringers (Saugerties Member) are gradationally overlain by light gray, clean limestones of the Onondaga Formation (Edgecliff Member). The lower part of the Onondaga section exposed along Old Kings Road (basal 2.0 m-thick non-cherty interval and overlying chert-rich strata) comprise the EdgecliffMember (ca 16m-thick). The lower 2.0 m of relatively chert-free, coral, brachiopod, and crinoid-rich pack- and grainstones ("Jamesville Quarry facies" of Brett and Ver Straeten, 1994) are capped by a thick section of medium-grained, cherty, crinoidal packstones ("Clarence facies" of Brett and Ver Straeten, 1994). Similar alternations of cherty and chert-free strata characterize the Onondaga Limestone in the Catskill area; chert-dominated facies are predominant locally, however.
The member level subdivisions of the Onondaga Limestone that are well-defined and easily recognized in central New York (see Brett and Ver Straeten, 1994) are less readily detectable in Hudson Valley outcrops. They can tentatively be separated by changes in chert and argillaceous content, and in bedding thickness.
A 6.6 m-thick covered interval, (which is exposed along Cauterskill Road, Mile 49.0 of this trip) at least in part represents the Nedrow Member. Overlying strata to the west along Rt. 23A comprise the Moorehouse Member. The coarse- to medium-grained, chert and crinoid-rich lithology of the Edgecliff Member below is replaced in the Moorehouse Member by finer-grained, cherty, wacke- to packstones characterized by brachiopod-dominated faunas. Calcite slickensides are common along bedding planes through the Moorehouse Member at Stop 3B; faulting, however, appears to be restricted along the bedding planes, associated with slippage of beds over each other during folding and overturn of the section.
The Onondaga Formation totals ∼44 m at Stop 3B; uppermost strata of the formation are covered. Fifty meters of Onondaga strata are reported from outcrops along the NYS Thruway at Saugerties, 8.5 mi. to the south (Feldman, 1985); the top of the Saugerties section is thought to be close to the contact of the Onondaga Limestone and overlying clastics of the Union Springs Member (Stop 4, next locality).
A geologic overview of Localities 1-3 and 5 is summarized here (see Figure 3) Post-Wallbridge deposition of the Glenerie, Esopus, Schoharie, and Onondaga Formations represent a succession of, respectively, intrabasinal carbonates, extra-basinal siliciclastics, mixed siliciclastic and carbonate sediments, and a return to fully intrabasinal carbonates. These trends are associated with initial tectonic quiescence and carbonate-quartz arenite deposition above the Wallbridge Unconformity (Glenerie Formation), followed by: 1) a pulse of active tectonism in the Acadian Orogen, accompanied by volcanism and deposition of the Sprout Brook Bentonites, transport and deposition of fine- to medium grained siliciclastics, and subsidence of the foreland basin (Esopus Formation); 2) decreased tectonic activity and lowering of topographic relief in the mountain belt, associated with a decrease in siliciclastic input into the basin and deposition of calcareous shales and siltstones to argillaceous limestones (Schoharie Formation); and 3) a return to tectonic quiescence, marked by deposition of intrabasinal carbonates (Onondaga Formation). This succession of events 1-3 comprises Acadian Tectophase I as it is recorded in the foreland basin fill of eastern New York State.
Superimposed on these tectonically-related trends are three major depositional sequences (DS-1 to DS-3). These sequences appear to be dominantly controlled by eustatic sea level changes. The first sequence (DS 1) comprises the Glenerie and Esopus Formations. Initial deepening above the Wallbridge Unconformity continues upward through the Glenerie Limestone and lower to middle Esopus Shale (note: deepening during Esopus time is in part due to tectonically-induced subsidence of the basin). Upward shallowing through the upper middle to upper Esopus Formation is truncated by submarine erosion below a sub-Schoharie unconformity at the base of DS-2. Initial deepening through the Schoharie Formation culminates in deposition of widespread dark shaly strata represented at Catskill by an interval of dark, siliceous to cherty shales in the lower part of the Aquetuck Member. Overlying increasingly more calcareous strata are associated with a general shallowing-upward reaches a maximum at or near the Schoharie-Onondaga formational contact. Initial deepening at the base of the Onondaga Limestone marks the base of DS-3; transgression continued upward through the Edgecliff and Nedrow Members. Trends through the overlying Moorehouse Member indicate another major shallowing-upward trend during late highstand of DS-3 . Transgression during the succeeding DS-4, which is dominantly represented by the overlying Union Springs Formation, was initiated during deposition of the upper part of the Moorehouse Member.

Cross over Kaaterskill Creek at Webber Bridge.
Drive through the Bakoven Valley, with deeply eroded black shales of the Bakoven Member (Union Springs Formation) overlain by glacial sediments.

Note outcrop of Stony Hollow Member
Note outcrop of Stony Hollow Member (Union Springs Formation) at intersection; more outcrops of Stony Hollow Member northward along Underhill Rd and at the crest of Rt. 23A to the southwest.

STOP 4. Onondaga Formation and Bakoven Member
Onondaga Formation and Bakoven Member of the Union Springs Formation.
East bank of Kaaterskill Creek, below the N.Y. Rt. 23A bridge. Type section of the Bakoven Member. PRIVATE PROPERTY.
The stream bed and east bank of Kaaterskill Creek expose the upper 0.85 m of the Onondaga Formation and the lower 27 m of the Bakoven Member of the Union Springs Formation. The abrupt change from shallow marine carbonates to basinal black shales seen in the outcrop mark the onset of Acadian Tectophase II.
Light-weathering, relatively fine-grained limestones with atrypid brachiopods, small rugose corals, and other forms characterize the Onondaga Formation at this locality. The upper 35 cm of limestone appears slightly darker in color and overlies a thin (1 -cm-thick) K-bentonite. Key upper Onondaga marker beds (e.g., the Tioga B-OIN bentonite at the base of the Seneca Member) are not seen at this outcrop; it is not known whether the exposed strata belong to the Moorehouse or Seneca Members. A thicker but partially covered outcrop (2.9 m-thick) of upper Onondaga strata occurs immediately north of Rt. 23 east of the bridge.
The Onondaga-Union Springs formational contact is abrupt, and features numerous bored phosphate pebbles and well-defined burrows that are visible in the creek when the water level is low. The contact is overlain by a thin (ca 2-3 cm-thick), highly condensed bed of phosphatized fossil debris (e.g., crinoid ossicles) and fish bone and teeth (NOTE: Please do not collect from the bone bed-this is a classic section and type locality). The bed marks a major sediment-starved flooding surface associated with tectonic subsidence of the Appalachian foreland basin at the onset of Acadian Tectophase II of Ettensohn (1985). For further discussion of this contact, see Ver Straeten et al. (1994) and Lindemann and Feldman ( 1987).
Overlying rusty-weathering, fissile black shales of the Bakoven Member represent deposition of fine-grained, organic-rich sediments in the proximal subsiding trough of the Appalachian foreland basin. Anaerobic conditions on the sea floor prevented colonization by benthic faunas; only rare leiorhynchid brachiopods and pelagic (?) dacryoconariids (Styliolina) and rare cephalopods occur in the shales. Three thin intervals of more calcareous strata (styliolinid packstones) occur upward through the section. The poorly resistant shale features numerous tectonized intervals (small shear zones and mesoscopic folds; Marshak, 1990) and fault surfaces, especially above the Onondaga Limestone in the lower part of the Bakoven Member.
The low valley to the west is floored by the Bakoven Shale, and is partially infilled with Pleistocene sediments. Roadcuts on the west side of the valley exposes the Stony Hollow Member of the Union Springs Formation (not the Mount Marion Formation as reported by Murphy et al., 1980; Marshak, 1990; Cassie, 1990).

Pass overturned to steeply-dipping Onondaga Limestone of Stop 3B

Schoharie Formation on left.

Esopus(?) Formation on right.

Catskill Escarpment and Hoogeberg Ridge
Catskill Escarpment and Hoogeberg Ridge visible in far and middle distance to right.

Road to scenic High Falls on Kaaterskill Creek
Road to scenic High Falls on Kaaterskill Creek, an excellent section of Otsego Member of the Mount Marion Formation.

Catskill Escarpment and Hoogeberg Ridge to right.

Onondaga Formation on right.

Onondaga exposure behind house on left.

Watch for "beefalo" in pasture to left of road.

Excellent view of Catskill Escarpment
Excellent view of Catskill Escarpment, with Kaaterskill Clove visible to right and back a little.

Katsbaan Reformed Dutch Church
Katsbaan Reformed Dutch Church, built 1732. Stone walls dominantly made of blocks of Onondaga Limestone, except front wall (brown-green sandstones of Austin Glen Formation).

Outcrop of Schoharie-Onondaga contact on right
Outcrop of Schoharie-Onondaga contact on right after turn (a left turn at the intersection would pass outcrops of the Onondaga Limestone, the Stony Hollow Member (Union Springs Formation), the Otsego Member and undifferentiated upper Mount Marion Formation, and lowest strata of the Plattekill Formation.

Saugerties Member (Schoharie Formation) on left.

Schoharie-Onondaga formational contact on right.

Onondaga Formation on left.

Site of 1994 Woodstock Festival on right.

Long outcrop of the Saugerties Member (Schoharie Fm.)
Long outcrop of the Saugerties Member (Schoharie Fm.) and most complete section of the Onondaga Formation in the Hudson Valley (along both sides of I-87).

Large quarry of Berne and Otsego Members
Large quarry of dark, shale-dominated Berne and Otsego Members (Mount Marion Fm.) on north shoulder of Mount Marion to right.

Crest of Mount Marion
Crest of Mount Marion, highest hill in the Hoogeberg Ridge. Type section of Mount Marion occurs at south end of the ridge, in a high south bank of Plattekill Creek.

Outcrop of Stony Hollow Member (Union Springs Fm.) on left.

Bridge over Plattekill Creek
Bridge over Plattekill Creek; outcrop of upper Stony Hollow Member (Union Springs Fm.) or Cherry Valley Member (Mount Marion Fm.) in creek bed on right.

Rest Stop

Middle part of Berne Member (Mount Marion Fm.).

Outcrops of Stony Hollow Member
Outcrops of Stony Hollow Member along I-87 for next 1.7 mi.

Long outcrop of Stony Hollow Member, both sides of highway.

Hurley Member and Cherry Valley member
Hurley Member (type section; Union Springs Fm.) and Cherry Valley Member (Mount Marion Fm.) exposed on left.

Lower part of continuous section of Berne Member
(Mount Marion Fm.).

Berne and Otsego Members (Mount Marion Fm.)
Boundary ∼2/3 height up bank on both sides.

Berne and Otsego Members in high bank on right.

Outcrops of Esopus and Schoharie Formations
On both sides of highway.

Glenerie, Port Ewen, Alsen, and Becraft Fms.
Outcrops of (in descending order) Glenerie, Port Ewen, Alsen, and Becraft Formations.

New Scotland, Kalkberg, Coeymans, and Manlius Fms.
Outcrops of (in descending order) New Scotland, Kalkberg, Coeymans, and Manlius Formations.

Ordovician Austin Glen Formation
Outcrops of Ordovician Austin Glen Formation on both sides of entrance ramp.

STOP 5. Esopus and Schoharie Formations.
Synclinal exposure on north side of Rtes. 199/209 east of Rt. 9W, north of Kingston.
Outcrops on the north and south side of Rtes. 199-209 expose upper strata of the upper member of the Esopus Formation and the unnamed, Aquetuck, and lower part of the Saugerties Members of the Schoharie Formation. The north outcrop is less weathered, and better displays various features of the strata.
16.3 m of the upper member of the Esopus Formation are exposed at Stop 5. These strata represent siltstones to fine-grained sandstones that cap the formation locally. The laminated unit at the base of the upper member seen in the Catskill region (Stops 1B & 2) is absent at this outcrop, but is partially exposed 0.4 mi. south at the north end of the Hudson Valley Mall (east of Rt. 9W). The contact between the laminated subunit and the overlying bioturbated siltstones to sandstones is sharp at the mall exposure. A continuous, almost complete section of the upper member is exposed along a railroad cut north of O'Reilly Street in southwestern Kingston (Stop #3 of Oliver et al., 1962), where the member totals 27.5+ m in thickness; the contact with the underlying middle member is covered below 5 m of the laminated subunit. The overlying siltstone-fine sandstone subunit totals 22.5 m in thickness, in contrast with 2.9 m at Stop 2 and 0.0 m at Stop 1 in the Catskill area.
The top surface of the Esopus Formation is well exposed on a eastward dipping bedding plane on the outcrop, where well-preserved Zoophycos and other trace fossils are exposed. The contact with the overlying unnamed member of the Schoharie Formation is sharp. Scattered quartz and phosphate pebbles are visible in the succeeding strata. The unnamed member at Kingston consists of bioturbated, calcareous, silty mudstones to argillaceous siltstones that total 32 m in thickness. This contrasts with ∼45 m at the railroad cut in Kingston and 9.2 m (Stop 2) to 5.0 m (Stop 1) in the Catskill area. Subtle banding is visible in the unnamed member along the outcrop. The prominent black, siliceous marker bed of the unnamed member ("black bed" of Oliver et al., 1962; 0.7 m-thick) is visible in the middle of the member along Rtes. 199-209.
The contact with the overlying Aquetuck Member (Schoharie Formation) is gradational. The highest white quartz pebbles in the upper part of the unnamed member were used by Oliver et al. (1962) to define the top of said member. These occur just above the uppermost prominent white band of limestone in the middle of the outcrop.
The siliceous/cherty nature of the overlying Aquetuck Member in the Catskill area and north is replaced by more calcareous strata in the Kingston area. The dark, siliceous, shaly interval near the base of the member is represented by a 3.2+ m-thick interval of blocky-weathering shales and thin limestone bands ∼3 m above the base of the member. Prominent "coffee and cream" banding is well-developed in the Aquetuck Member as well as the other members of the Schoharie Formation along the outcrop. White nodular limestone bands in the Aquetuck Member are replaced upward by more continuous, tabular limestone beds in the overlying Saugerties Member.

STOP 6. Bakoven and Stony Hollow Members of the Union Springs Fm.
Cut along City View Terrace immediately east of N.Y. Rt. 28.
This roadcut and a subjacent cut along Rt. 28 expose the upper 10 m of the Bakoven Member and the lower 23 m of the overlying Stony Hollow Member (Union Springs Formation). The Bakoven Shale at Kingston consists of ∼100 m of fissile black shale (Rickard, 1989, Ver Straeten et al., in prep.). Similar to Stop 4, the member is nearly barren of fossils; styliolinids, cephalopods, and Panenka bivalves comprise the dominant forms found here. The Bakoven Member features numerous deformational structures similar to those at Stop 4, which include several zones of sheared and mesoscopically-folded shales below the overlying resistant strata of the Stony Hollow Member.
The Bakoven-Stony Hollow contact is gradational at Kingston. Calcareous, buff-weathering, thinly laminated to burrow-mottled lower Stony Hollow strata also feature a low diversity, anaerobic to dysaerobic fauna of dacryoconariids and rare, small bivalves and brachiopods. Grain size increases upward through the Stony Hollow Member from laminated claystone-mudstone couplets in the lower part to fine-grained sandstones near the top of the unit. Biofacies upgrade from basinal anaerobic/dysaerobic dacryoconariid-dominated faunas to fully aerobic brachiopod-crinoid-trilobite shallow marine assemblages through the Stony Hollow and Hurley Members. A dysaerobic, dacryoconariid-leiorhynchid brachiopod-cephalopod assemblage in the overlying Cherry Valley Member indicates a return to deeper water conditions associated with transgression. The bottom of the Cherry Valley Member is a sequence boundary at the base of the Mount Marion Formation. The entire Stony Hollow and Hurley Members (type sections) and Cherry Valley Member (eastern clastic facies reference section) are exposed in the immediately adjacent area (see Griffing and Ver Straeten, 1991, p. 247-249).

Cross Sawkill Creek.

Berne Member on left.

Outcrop of Berne Member
Outcrop of Berne Member adjacent to outcrop along I-87/NYS Thruway

STOP 7. Berne and Otsego Members Mount Marion Fm.
Abandoned quarry along Ulster Co. Rte 31, north of Buzzanco's Greenhouses. PRIVATE PROPERTY: contact Mr. Buzzanco at the greenhouses. Locality 3 of Ver Straeten, 1994.
The upper part of the Berne and lower part of the Otsego Members of the Mount Marion Formation (Depositional Sequence 5 of this paper) are exposed in this abandoned shale pit). ∼55 m of dominantly dark gray mudstones and claystones crop out in the quarry. Cyclically-occurring shell beds, generally separated by 3-8 m of unfossiliferous mudstones, feature distinctive brachiopod-dominated faunas that in general increase in diversity upward through the interval exposed. These small-scale cycles represent individual parasequences. The strata are also punctuated by packages of thin sandstone beds; recent work shows that most of the shell beds and clusters of thin sandstones have been successfully correlated along the outcrop belt along much of the eastern New York outcrop belt (> 110 km, Kingston to Schoharie; Ver Straeten, 1994).
The base of the quarry lies ∼85 m above the top of the Union Springs Formation. Regionally the contact of the Berne and Otsego Members is marked by the occurrence of a richly fossiliferous coral-brachiopod biostrome (Halihan Hill Bed of Ver Straeten, 1994). This bed, which occurs ∼12m up in the quarry section, marks the first known occurrence of the classic fauna of the Middle Devonian Hamilton Group. Regional study indicates the bed represents initial flooding after a significant fall in relative sea level within Depositional Sequence 5; an abrupt contact of the Halihan Hill Bed with underlying claystones is due to local to regional submarine erosion of underlying sand-rich strata during sea level lowstand (Ver Straeten, 1994).
Overlying dark shale-dominated strata mark a return to deeper water settings associated with continued transgression. Low diversity shell beds, characterized by leiorhynchid and Mediospirifer-Athyris brachiopod associations characterize a 30 m-thick interval above the Halihan Hill Bed. Shell beds in the upper part of the quarry show an increase in diversity, apparently associated with a decrease in water depth. A package of thin sandstones at the top of the quarry are succeeded locally by a prominent, richly fossiliferous sandstone (up to 2.5 m-thick) that forms the caprock of waterfalls and ridges along the Hoogeberg Escarpment in eastern New York (e.g., High Falls of Kaaterskill Creek, SW of Catskill).

Otsego Member on right.
Exposures of middle Mount Marion strata for next 1.0 mi.

Sawkill Creek

Hill Rd. to flagstone quarries on left.
Hill Rd. on left; road to extensive turn-of-the-century flagstone quarries in upper part of the Mount Marion Formation.

Intricately decorated house
Intricately decorated house on right side of Sawkill Rd.

Road to more abandoned flagstone quarries on left.
Jockey Hill Rd. on left; road to more abandoned flagstone quarries.

Upper Mount Marion Formation
Massive sandstones of upper Mount Marion Formation on right.

Quarry in upper part of Mount Marion
Quarry in upper part of Mount Marion on right behind houses.

Roadside cuts in upper middle part of Mount Marion
Roadside cuts in upper middle part of Mount Marion Formation for next 1.0 mi.

Upper part of Mount Marion Formation for next 0.3 mi.

STOP 8. Upper part of the Mount Marion Formation.
Abandoned flagstone quarry north of N.Y. Rt. 28 and east of Onteora Lake. PRIVATE PROPERTY.
Turn right into entrance to abandoned flagstone quarries; park and walk up roadway past concrete barriers. Extensive exposures throughout the quarries. This stop will concentrate on rocks along the entrance road and in the upper quarry behind abandoned buildings on quarried cliff.
This abandoned quarry features excellent exposures of nearshore marine to non-marine transitional deposits in the upper part of the Middle Devonian Mount Marion Formation. The upper strata of the formation are dominated by cyclic alternations of interbedded mudstone-sandstone facies and flaggy-bedded sandstone bodies on the order of 10 m total thickness. The coarser, sand-dominated strata may feature thin beds to lenses of quartz and chert pebble conglomerate. Normal marine faunas (brachiopods, bivalves, etc.) occur through most of the section; however, apparent plant-root traces in some beds indicate periodic subaerial exposure during deposition.
This locality was originally quarried around the turn of the century for bluestone flags that were used in New York City for sidewalks and curbstones; the quarry was reactivated during the 1970's for production of concrete aggregate (Banino, 1987). Two main levels were worked for quarry stone in the past. The main quarry face of the lower level exposes ∼9 m of section, which is comprised of: a) a lower, 1.4 m-thick sandstone body; b) a middle 5.5 m-thick unit of interbedded dark gray mudstones and thin sandstones, which coarsens toward the top; and c) 2.0 m of flaggy-bedded sandstones at the top.
The upper level of the quarry features extensive lateral exposures of the flaggy-bedded sandstones. The top 0.5 m of the middle mudstone unit of the lower quarry face are exposed in the floor of the upper quarry, where scattered brachiopods (Mucrospirifer and Devonochonetes coronatus) and bivalves can be found. A large area of the upper quarry is floored by a 10 cm-thick quartz-rich sandstone with a symmetrically rippled top and common Cruziana trilobite traces on the underside of the bed.
The mudstone unit is overlain by conglomerate lenses and/or a pebbly, coarse sandstone bed at the base of the quarry face. The overlying interval (∼1 m-thick) is characterized by thin- to medium-bedded sandstones and thin, black, fine-grained, organic- and pyrite-rich beds. These thin (∼1-5 cm-thick), recessed interbeds contain abundant plant material, which include lenses of in situ root traces; yellow to white mineral crusts (Melanterite and Epsornite?) weather out of the crevices, probably associated with the decay of pyrite. Single valve rhynchonellid brachiopod shells also occur in some of the thin sandstones.
Overlying strata (ca 5 m-thick) are dominated by medium-bedded lithic arenites that appear planar to cross-bedded. Pebbly lenses occur scattered through the section. Extensive bedding plane exposures of the flagstone interval are visible in the southern part of the quarries, where several unusual trace fossils have been found. A discontinuous but prominent crevice, ∼halfway up the flaggy sandstone unit, is bounded by two lighter- and more smoothly-weathering sandstone beds. The upper bed (∼40 cm-thick), which forms the cap rock of the east wall, appears in side view to feature in situ plant root traces. Overlying sandstones are darker and flaggy bedded, similar to the beds below.
The top surface of the sandstone body is rippled (symmetric ripples) and is abruptly overlain by olive-gray colored, crumbly-weathering, sandy mudstones and thin sandstones. Relatively large Camarotoechia and Mucrospirifer brachiopods occur in the upper part of the sandstones (as densely packed lenses) and the overlying sandy mudstones. North of the quarry, in the woods, a relatively steeply-dipping body of thin, highly trough cross-bedded sandstones overlies the position of the olive-gray shales. It is not clear at present if this unit represents a submarine or subaerial channel-form deposit.

Upper Mount Marion strata.

Mount Marion in small quarry on right.
Marine shales in uppermost Mount Marion in small quarry on right.

Top of marine section
Top of marine section at quartz-rich sandstone at base of exposure on left hand side(= top of Mount Marion Fm.); overlying thick sandstones are in the succeeding Ashokan Formation.

Exposure of Ashokan Formation on right side.

Outcrops of Plattekill Formation on left and right
Lowest redbed exposures along Rt. 28.

Plattekill Formation on right.

STOP 9. Plattekill Formation.
Cuts along N.Y. Rt. 28, 0.7 mi. west of intersection with N.Y. Rt. 375.
This outcrop of red, green, and olive mudstones (lower part) and medium-gray, cross-bedded sandstones (upper part) of the Plattekill Formation are a gross generalization of facies that characterize the remainder of the Middle and Upper Devonian of the Catskill Front. The lower 5 m of green, green-mottled red, and red mudstones feature calcrete nodules, indicative of development of paleosols on subaerial flood plains. Plant fossils and root traces are visible throughout much of the section; distinctive weathering styles appear to characterize different paleosol units along the outcrop. Overlying olive-weathering mudstones (∼1.5-3.0 m-thick) are erosively capped by -4 m of planar cross-bedded, lithic arenites that represent deposition within a migrating fluvial channel.
Pedersen et al. (1976) reported a zone of deformation in a paleosol horizon - 2.5 above the base of the section. These structures on close examination appear to resemble separate, low angle, basin- or bowl-shaped structures ∼0.5 to 1.0 m in diameter. They are similar to "pedogenic slickensides" described from redbeds of Silurian-, Devonian-, and Pennsylvanian-age by Gray and Nickelsen (1989). Slickenlines on the bottom-side of the structures visibly radiate outward and upward through 180° laterally on the outcrop. Pedogenic slickensides form in modern vertisols associated with seasonal wetting and drying of expansive clays in the B soil horizon (Gray and Nickelsen, 1989; Ciolkosz et al., 1979).
The succession of events for Stops 4 and 6-9 and overlying strata are summarized here (see Figure 4). Six major depositional sequences are recognized above (and including) the top of the Onondaga Limestone in New York State (see body of paper above). These sequences correspond to five formation-level subdivisions of the Hamilton Group (upper Onondaga and Union Springs Fms., Mount Marion/Oatka Creek Fms., Skaneateles Fm., Ludlowville Fm., and the Moscow Fm., Sequences DS4-8, respectively) and the overlying Tully and Geneseo Formations (Sequence DS9). In the Catskill Front, marine rocks of Sequences DS4 and DS5 feature recognizable transgressive and highstand systems tracts (see body of paper). Strata of the overlying Sequences DS6-9 are fully non-marine; no sequence stratigraphic framework for these fluvial-dominated rocks has been proposed (however, see Bridge and Willis, 1994).
A larger-scale set of trends related to Acadian Tectophase II are superimposed onto Depositional Sequences DS4-9. Widespread, intrabasinal carbonate deposition during the late, quiescent stage of Acadian Tectophase I (Onondaga Limestone) is succeeded by a thick, wedge-shaped body of siliciclastics associated with Acadian Tectophase II (Hamilton Group). The progression of Tectophase II is characterized by: l) onset of renewed tectonism accompanied by increased volcanism and deposition of the Tioga Bentonites, subsidence of a proximal foredeep (eastern NY) and uplift of a peripheral bulge (western NY), and transport/deposition of initially fine-grained black shale. This was followed by the onset of progradation of progressively coarser clastic marine sediments into eastern New York (Union Springs and Mount Marion Fms.); 2) decreased tectonism in the Acadian orogen and progradation of non-marine facies into eastern New York (Ashokan, Plattekill, and Manorkill Formations). Decreasing siliciclastic input is indicated by a general upward increase in carbonate content in upper Hamilton Group strata in central to western New York (Ludlowville and Moscow Fms; this trend is analogous to general trends through the Schoharie Formation during Tectophase I); and 3) a return to tectonic quiescence and low relief of tectonic highlands in the late Middle Devonian, indicated by deposition of intrabasinal limestones (Tully Formation). Stages 1-3 comprise Acadian Tectophase II as it is developed in New York State. Onset of black shale deposition in the latest Middle Devonian (Geneseo Formation) marks the onset of Acadian Tectophase III.

B6: ORDOVICIAN ROCKS IN THE MOHAWK VALLEY: GEOLOGIC SITES FOR
EDUCATION OF HIGH SCHOOL AND COLLEGE STUDENTS
JOHN IRWIN GARVER
Schenectady NY 12308-2311
garverj@unvax.union.edu
The Mohawk Valley has outstanding bedrock geology and the stratigraphy of the Middle Ordovician rocks reflects the tectonic events associated with the Taconic orogeny (Figures 1-4). One advantage of teaching in this area is the ability to integrate the local stratigraphic record into classes concerned with stratigraphy, sedimentology, depositional environments, tectonics, and other geologic studies (Garver, 1992). Most of the Mohawk Valley is underlain by Middle Ordovician rocks that were deposited prior to and during the collision of the Taconic arc. This collision is clearly reflected in changes in the stratigraphic record, as well as structural and metamorphic events farther to the east (see Kidd et al. [this volume] for the structural aspects of the frontal thrust; see Hollocher [this volume] for the metamorphic aspects across the Taconic Orogenic belt). These changes include: 1) a deepening upwards trend that reflects tectonic subsidence; 2) lateral facies changes that reflect the basin geometry; and 3) paleocurrent trends that ultimately define the nature of coarse clastic infilling during the orogeny. The immediate focus of this field trip is on the stratigraphic record of the Taconic orogeny in the Mohawk Valley. In our examination we will look at separate pieces of the stratigraphy in ascending stratigraphic order - we will be traveling upward through time. We will examine changes in depositional environments and how these changes can be inferred from the rock record. We will also examine the lateral variation in the stratigraphy to infer changes in the basin geometry. Finally, we will use paleocurrent indicators to infer the shape of the basin and the flow directions of sediment fill during the Taconic orogeny.
This trip has two goals. The first goal is to gain an understanding of how to interpret depositional environments and how the changes in depositional environments can be used to infer tectonic events. The second, and perhaps most important, goal is to discuss how these different geologic sites can be used for the education of students. I have little experience with primary and secondary students on the outcrop, but I do have considerable experience with undergraduate students in the field and some of the challenges encountered in this arena certainly apply to younger students. Of the five sites on this trip, I use four of them in my course "Stratigraphy and depositional environments of New York", which I teach at Union College (for a complete description of the course, see Garver, 1992). These sites are advantageous because they focus on the most dramatic changes in the stratigraphy and they are easily accessible - most are in public parks.

B6: ORDOVICIAN ROCKS IN THE MOHAWK VALLEY: GEOLOGIC SITES FOR
EDUCATION OF HIGH SCHOOL AND COLLEGE STUDENTS

Canal Park and Lock 9 to the left.

Sign tells of the displacement on the Wolf Hollow Fault.
Bear left and continue on Wolf Hollow Rd. Note historic sign telling of the displacement on the Wolf Hollow Fault.

STOP 1: Hoffmans Fault
In Wolf Hollow a high-angle normal fault cuts the Schenectady Formation and older rocks (Figure 1 and Figure 10). This fault, which trends about 030 (north-northeast) is one of a family of high-angle normal faults that were probably active in the Middle Ordovician. Most of these faults dip to the east and the eastern block is downdropped- some notable exceptions occur farther to the west at the "Noses" (Figure 1). At this site one can see slightly tilted rocks of the Schenectady Formation (interbedded sandstone and shale) on the east side of the road. On the west side of the road are exposures of the Beekmantown Group - these are especially easy to see when the leaves are off the trees. Not visible from here are also exposures of the Trenton limestones and the Utica Shale, both resting above the Beekmantown Group. Using stratigraphic mismatch we can determine the apparent throw on the fault. Although the sign at the entrance to Wolf Hollow states that the fault has 1000 feet of displacement, is difficult to calculate the exact displacement because there are no clear stratigraphic markers in the Schenectady Formation. (See Locality 19 in Fisher, 1980). Using simple cross sections and reasonable stratigraphic thicknesses for these units, the apparent displacement is somewhere between 200 and 400 meters.

Schenectady Formation on the east side
Note the excellent exposures of the Schenectady Formation on the east side of the road along the entire length of the Hollow.

Exposures of the very fossiliferous Trenton Group limestones
Exposures of the very fossiliferous Trenton Group limestones (Glens Falls Limestone) on the left (west) side of the road).

Beekmantown Group (Wolf Hollow Limestone)
Several outcrops of carbonates of the Beekmantown Group (Wolf Hollow Limestone which is Lower Ordovician) along the right (north) side of the road.

STOP 2A: Quarry at Manny's Corner
Quarry at Manny's Corner - Beekmantown , Black River, Trenton groups
Pull off in small overgrown drive on left side of road to old abandoned quarry. This is private property. Please call Cranesville Block Company (518-346-5749) for permission to enter the "Manny's Corner quarry".
In this quarry, the Cambrian to Lower Ordovician Beekmantown Group is disconformably overlain by Middle Ordovician carbonates of the Black River and Trenton Groups (see Locality 17 of Fisher, 1980). The floor of the quarry is composed of the Lower Ordovician Wolf Hollow Member of the Tribes Hill Formation. The Tribes Hill Formation is one of the upper units in the Beekmantown Group, a widespread and relatively uniform sequence of carbonates and dolomites found throughout eastern North America (for other stops in this unit see Friedman, 1972). Note that this unit is dolomitic, has algal mounds, and is replete with a single species of gastropod (Ecculiomphalus ). The walls and nearby outcrops (north side of Rt. 67) are composed of the Lowville Limestone, the Amsterdam Limestone, and the Glens Falls Limestone (&tilds;Larrabee Limestone and the overlying Shoreham Limestone) all of which belong to the Black River Group and the Trenton Group (see Fisher, 1965; 1977). At this exposure, the unconformity between the Beekmantown Group and the overlying Middle Ordovician rocks is well displayed, and regional stratigraphic studies indicate that the upper part of the Beekmantown Group (the Lower Ordovician part) is missing. The Lowville Limestone is generally not fossiliferous, but it contains birdseye texture, a few vertical burrows, and mudcracks; locally it is dolomitic. The Amsterdam Limestone is irregularly bedded and the contact between the two units is marked by the first fossiliferous beds. These thin beds are very fossiliferous, with brachiopods, rugose coral, crinoids, and trilobites dominating the fauna. As you examine the outcrop from bottom to top, note the distribution of coral.
For students in "Stratigraphy and depositional environments of New York," this project involves measuring a short (10 m) stratigraphic section, in which they describe the fossil content of the units, and interpret the depositional environments of these shallow marine rocks. As we will see, the interpretation of the depositional environments is aided by carefully noting the sedimentary structures and faunal content of each rock unit. After examining the rock we will have a brief discussion about relative sea level changes and the role of tectonic activity. The change in faunal content upsection indicates deepening through time and most students use their newly acquired knowledge concerning sea level changes and basin subsidence to explain this apparent transgression. As we will discuss, the deepening in the stratigraphic section may be related to tectonic subsidence. The goal of this phase of the project is to relate depositional environments and the unconformity to regional or global events that might have produced this particular sequence.

STOP 2B: Road cut across from Manny's Corner Quarry
Trenton Group Limestone
Exposed in the roadcuts along the north side of Rt. 67 are excellent exposures of the extremely fossiliferous Glens Falls Limestone. Note that these beds contain fossiliferous limestone (locally with scoured bases and graded beds) with interbedded calcareous shale which is also fossiliferous.
These rocks are replete with fossils; brachiopods, bryozoans, trilobites, crinoids, and others. Of particular note are two rather distinct trilobites. A small trilobite, Cryptolithus tesselatus, is common in the resistant limestone beds - they are typically the size of a fingernail. A much larger trilobite, Isotelus gigas, is common (unfortunately as fragments) in both the limestone bed and the calcareous shale. These are important index fossils. As we will see at Canajoharie Creek, geologists generally use fossils for either biostratigraphy or for reconstructing depositional environments. The concepts of biostratigraphic analysis are fundamental and are the basic tenet of the science of stratigraphy. As organisms evolve through time they change and new species eventually become extinct. By carefully studying the vertical distribution of distinct and common species, paleontologists have been able to determine fossil zones that are defined by the occurrence of a particular index fossil(s). Cryptolithus tesselatus is an index fossil for these beds. As we move upsection we will no longer see this fossil because it had become extinct. The distribution of index fossils and other more common and long ranging fossils is very closely related to depositional environments. (Good index fossils are found in many depositional environments). Some fossils can be used to determine the relative water depth. In the Mohawk Valley there have been very detailed studies of fossils with respect to water depth (see Cisnee and Chandlee, 1982; Cisne et al., 1982). As we will discuss at the outcrop, the assemblage of fossils in this outcrop suggests deeper water than does the assemblage in the underlying Amsterdam Limestone. Additionally, the occurrence of fine-grained calcareous shale suggests deposition below the normal wave base (the effective depth to which fair weather waves affect the bottom sediments). In this regard the stratigraphic section is deeper than that at the quarry. A deepening trend such as this is referred to as a transgression.

Dolostone of the Beekmantown Group
Small public park (to left] with very nice exposures of the dolostone of the Beekmantown Group.

Exceptional exposures of the Utica Shale
Note the exceptional exposures of the Utica Shale across the interstate in the exit ramp for the eastbound traffic.

Middle Ordovician Trenton Group in opposite lane
Excellent exposure of limestones of the Middle Ordovician Trenton Group in the opposite lane. Above this exposure (on Rt. 5S) is the conformably overlying Utica shale. At the far end of the road cut on I-90, the uppermost beds of the Beekmantown group are exposed. Once again, the Knox unconformity separates the Trenton Group and the Beekmantown Group.

Cross the Noses fault.
This fault belongs to the family of normal faults that cut Middle Ordovician and older rocks in the Mohawk Valley, and is therefore similar in timing to the Hoffmans Fault. This fault and others to the west bound an upthrown block (horst) that exposes some of the oldest rocks in the Mohawk Valley. Note that this horst was probably a topographic high during the Middle Ordovician- as can be seen from the regional geologic map (Figure 1), the Trenton Group was not deposited on this block. Elevation of the horst above sea level may explain this distribution of rock units.

Precambrian Basement and overlying rocks of Beekmantown Group.
Across 1-90 and along the barely visible Rt 5S are prominent exposures of the Precambrian
Basement and the unconformably overlying rocks of the Beekmantown Group. The contact between
these rocks, which can be seen along Rt 5S, shows evidence of structural disruption, and the
interpretation of the contact is complicated by this disruption. The Precambrian rocks are provisionally
assigned to the Peck Lake Formation, which is a garnet biotite gneiss about 1.1 Ga
(billion years old). Although this contact may be faulted, in this area the Beekmantown Group is
known to unconformably overly the Precambrian Basement. For a discussion of this area see
Locality 12 in Fisher, 1980.

Cliffs of the Upper Cambrian Little Falls Dolostone
For about 0.5 miles there are very steep cliffs of the Upper Cambrian Little Falls Dolostone on the left (south) side of I-90. This unit, which is part of the Beekmantown Group, is stratigraphically lower than all of the other exposures of the Beekmantown Group that we will see on this trip. In places this unit has vugs containing doubly terminated quartz crystals locally known as the "Herkimer Diamond".

STOP 3: Canajoharie Creek (Floral Avenue)
Beekmantown, Black River, Trenton groups
Park at end of Floral Ave in dirt parking lot at the end of the street. Walk toward river and take foot path upriver for several hundred meters.
Similar to the exposures at Manny's Corners, limestone and shale of the Trenton Group disconformably overlie dolostone of the upper part of the Beekmantown Group in the river bed of Canajoharie Creek. This well-exposed and very fossiliferous stratigraphic section records important changes in the depositional history of the Mohawk Valley. Rocks in the Canajoharie Creek river bed include the Chuctanunda Creek Dolostone, which is pan of the Beekmantown Group, and the disconformably overlying limestone and shale of the Trenton Group. Interbedded limestone and shale of the "lower Trenton Group" is conformably overlain by the Utica Shale, which is some 305 meters thick at this locality. All rocks of the Trenton Group were deposited during the Trentonian stage of the Middle- Late Ordovician (circa 448-458 Ma) and the rocks of the Chuctanunda Creek member of the Tribes Hill Formation were deposited during the Gascondian stage of the Early Ordovician (circa 505-488 Ma).

STOP 4: Canajoharie Creek (Wintergreen Park) - Utica Shale
The second stop, which is near the top of the Utica Shale, can be accessed from Wintergreen Park (only open during the summer but it is possible to visit this locality year-round). Here the Utica Shale is a black, laminated and locally fossiliferous shale with minor thin (generally <2-5 cm) seams of light gray and rusty weathering bentonite. The bentonites can be recognized easily because orange-red rusty streaks emanate from them. The rusty streaks are caused by the oxidation of pyrite which is common in the bentonitic seams. We will walk downstream to examine a fossiliferous section containing the trilobites Triarthus and Isotelus, as well as brachiopods and graptolites. Locally, very large nautiloids can be found in this outcrop. For pioneering work on the Utica shale (slightly to the west) see Kay, 1953.
The changes in depositional environments and basin geometry during the deposition of these rocks are well recorded in both the stratigraphy and lateral and vertical distribution of fossils. As you can imagine, individual organisms (fossils) preferred different depositional settings and therefore they commonly are found in only certain facies. For example, a thick-shelled pelecypod may inhabit a high-energy niche in the shoreface while a thin-shelled brachiopod may have found its niche in a deep-water environment. Once preserved in the geologic record, these individuals may serve as useful indicators of the energy level or water depth during deposition of a particular unit. In addition, the distribution of such fossils may provide important information concerning the original configuration and deepening trends within a basin of deposition. (see Cisnee and Chandlee, 1982; Cisne et al., 1982). From the enormous database collected by John Cisne and his co-workers, Ray Gildner has developed a Hypercard stack (Macintosh-based) that shows the distribution and occurrence of 10,000 fossils in the database. In essence, one can see the places where an individual fossil was observed in many stratigraphic sections. The distribution of two depth-sensitive individuals are shown in Figure 5. Here you can see that the distributions of Triarthus and Cerarus are very different; Triarthus is restricted to the eastern (deeper) sections and Cerarus is present only in the western (shallower) sections. From this we can see that the basin deepens to the west.
The occurrence of the bentonite is extremely important (Figure 5). Bentonite is commonly interpreted to represent volcanic ash. Therefore not only can these thin beds serve as chronostratigraphic markers (one bed is the same age everywhere), but they can also tell us that volcanic activity occurred nearby. Although the stratigraphy records this dramatic subsidence, this volcanic ash is the first direct sample of the Taconic arc to the east.

Precambrian Dike across the river
Again the Little Falls Dolostone is exposed to the right (south), but here you can also see a well exposed outcrop of the Precambrian basement across the Mohawk river on Rt. 5N. This exposure is also provisionally assigned to the Peck Lake Formation (circa 1.1 Ga) and is intruded by a dark weathering basaltic dike that has been dated at about 700 Ma (see locality 12 in Fisher, 1980). Dikes of about this age are common in the Adirondacks.

Trenton Group resting unconformably on the Beekmantown Group
Exposure of Trenton Group resting unconformably on the Beekmantown Group. Look closely because
the unconformity is at the very beginning of the outcrop (west side).

Exposures of the Beekmantown Group on the right.

Cross the approximate trace of the Wolf Hollow Fault.

Middle Ordovician Schenectady Formation
Excellent exposures of interbedded medium- to thin-bedded sandstones and shale of the Middle Ordovician Schenectady Formation. If observed from a distance, this turbidite sequence shows low-angle truncations that probably represent channeling on a submarine fan.

Exposures of the Middle Ordovician Schenectady Formation.

STOP 5: Plotterkill Preserve - Schenectady Formation
The Plotterkill Preserve is a private preserve that surrounds the lower reaches of the Plotterkill stream which drains north into the Mohawk River (Figure 12 and 13). The stream cuts into and beautifully exposes sandstone and shale of the Middle Ordovician Schenectady Formation (see Locality 30 in Fisher, 1980). The Schenectady Formation is Mohawkian in age (upper Middle Ordovician). Most of the formation (and the Utica Shale) is restricted to the Nowadagan stage but the lower beds belong to the Canajoharian stage (i.e., the top of the Mohawkian). In general the Schenectady Formation is composed of interbedded light-brown- to buff-weathering, medium- to fine-grained sandstone with interbedded gray to black laminated shale. The sandstones are laminated and rippled and locally graded. They commonly have flutes and grooves on their bases and ripples on the tops. The unit is virtually unfossiliferous with exception of uncommon graptolites. These sandstones are interpreted to have been deposited in very deep water and to have been transported to the site of deposition by turbidity currents.
Although many geologists accept the notion that the clastic material had a source to the east, the paleocurrent data from this unit do not clearly support this contention. Using data collected from the Plotterkill Preserve and data from several other sites in the Mohawk Valley one can reconstruct the paleoflow directions within the basin during deposition. Virtually all of the pareocurents trend to the north-northeast. As exaplained above, these current directions may reflect sedimentation on a submarine fan that formed axial to the principal structural trend of the foreland basin.
For students in Stratigraphy and depositional environments of New York, this project involves measuring, plotting, and interpreting paleocurrents and relating this information to concepts of basin infilling. In the field, students spend several hours measuring flutes, grooves, and ripple marks from relatively flat-lying sandstone beds with a Brunton compass. Measurements are then entered into computer data files and plotted using Macintosh software. In addition to the data set collected by the students (all the data from different groups are merged), they are given two additional data sets from geographically separated outcrops of the same unit.
The Schenectady Formation has very good paleocurrent indicators - mainly flute and grooves. Virtually all of the paleocurrents in rocks of the Schenectady Formation in the Plotterkill preserve indicate flow from the southwest to the northeast (flow direction to about 020 to 030°) (see Figure 14 ). If these sediments were derived from the Taconic Arc to the east, then why do the ancient flow directions tell us that the sandstone flowed from the southwest? The answer lies in a possible interpretation concerning how turbidites flow in a basin and the shape of the basin. Turbidites flow downslope. If they encounter the deepest part of the basin, they tend to turn to flow along the basin axis as opposed to flowing upslope on the other side. In this regard. we recognize that foreland basins can develop two different types of submarine fans. The first, called a lateral fan, is composed of turbidites that accumulate directly off the edge of a large source terrain. In this case, all of the paleocurrents tend to record flow directly away from the source. The second, called an axial fan, records flow parallel to the source and possible parallel to the structures that influenced the source. This part of the Schenectady Formation was most likely deposited as an axial fan with a main feeder canyon somewhere to the south. It is interesting to note that the average paleocurrent direction in the Schenectady Formation is perpendicular to the direction of tectonic transport (thrusting direction) in the western Taconics (about 290 to 300° as determined at five localities). If thrusting in the Taconics was related to basin formation, then one would predict a foreland basin with a trough-like axis oriented at about 020-030° - exactly the orientation of the paleocurrents. A similar trend in sediment dispersal was recognized in correlative rocks in Pennsylvania, where the sandstones of the Martinsburg Formation indicate basin infilling by both lateral and axial submarine fans (McBride, 1962).
In this area, the Schenectady Formation is underlain by the Utica Shale (i.e. Wintergreen Park), and together their thickness is nearly 1000 to 1800 meters. This shale/sandstone package thins gradually to the west and thickens dramatically to the front (east edge, near Troy) of the Taconic Range. The extreme thickness and the composition of these strata is an important sedimentation pattern. The thickness of strata preserved in a basin is generally a reflection of the relative depth or the amount of subsidence that occurred in the basin. This room for sediment is sometimes referred to as "accommodation space" because if there is not room for sediment (a basin), sediment tends to not accumulate. With this in mind, one could postulate that the basin was deepest, or experienced the most subsidence from here (Piotterkill) east to the Troy area where the unit thickens considerably. Shale that filled the basin has no obvious provenance or source area because the particles are so fine-grained. However, recent studies suggest that this shale reflects the changes in the composition of the thrust complex to the east (Garver et al., 1996). Sandstones contain coarse-clastic material that represents identifiable fragments of the source region. Because these and correlative sandstones have a distinct composition, workers have postulated that these sandstones had a source that lay to the east that was composed of mainly sedimentary rocks. Sandstones of the Schenectady Formation contain quartz, feldspar, and sedimentary rock fragments (with minor metamorphic and volcanic rock fragments), and a minor detrital mica.
The Schenectady Formation, therefore, was derived from the Taconic orogenic belt to the east - in this regard it is a synorogenic deposit. Paleocurrents indicate that the flow of sediment was to the north-northeast, which is exactly what we would predict if the structures presently preserved if the Taconic mountains produced a foreland basin. The sandstones and the shales were derived from the thrust complex and are therefore rich in sedimentary detritus and recycled grains - detritus directly from the Taconic arc is rare.

B7: TREATMENT OF SURFACE AND GROUNDWATER: TOUR OF MOHAWK VIEW WATER TREATMENT PLANT
ROBERT J. MASWICK
Chief, MVWTP Operator
Latham Water District
347 Old Niskayuna Road
Latham, NY 12110
PHILLIP D. SNOW, PHD
Civil Engineering Department
The Mohawk View Water Treatment Plant is unique in that it has three different raw water supplies: 1) a surface water reservoir in a suburban housing area with occasional algal blooms; 2) a ground water supply with high amounts of soluble iron and manganese; and, 3) a river supply with varying flows and water quality problems. The tour will show the wide variety of treatment methods used to deal with the water quality problems associated with these various raw water sources.

B7: TREATMENT OF SURFACE AND GROUNDWATER: TOUR OF MOHAWK VIEW WATER TREATMENT PLANT

STOP 1.Overview of Latham Water District Water Supply
Overview of Latham Water District Water Supply
The major components of the Latham Water District Water Supply include the Intake Channel, Raw Water Pump Station, Mohawk View Water Treatment Plant (MVWFP), Clearwell storage tanks, the Mohawk View & River Road High Lift Pump Stations, and Lagoons for settling basin and backwash wastes. The water treatment plant consists of the Aeration Basin, Flocculation and Coagulation Basins, Settling Basins, Rapid Sand Filters, and chemical feed facilities. The well supply, completed in 1965, now consists of 5 wells, with a permitted withdrawal of 7.5 MGD. The well supply receives full treatment at the WTP. Although the RRWTP was abandoned in 1985, the Stony Creek Reservoir today still supplies over 5.1 million gallons of raw water (on an almost daily basis) to the MVWTP.

B8: ENVIRONMENTAL TECHNOLOGY AND PRESERVATION: THE PINE BUSH, LANDFILLS, AND GROUNDWATER INTEGRITY
JACQUELINE A. SMITH
ERIC ESLINGER
Alpha Earth, Inc.
10 Sussex Road
Glenmont, NY 12077
DAVID L. HANSEN
Landfill Technologies, Inc.
P.O. Box 519
West Sand Lake, NY 12196
The active Albany Interim Landfill and the closed Albany City Landfill are located in the City of Albany, New York, in a region of stabilized dunes known as the Pine Bush (Figure 1). Surface deposits in the Pine Bush consist of highly permeable sands originally deposited by the paleo-Mohawk River as delta deposits during the high stand (maximum extent) of glacial Lake Albany. The sands constitute a large unconfined aquifer. Subsurface investigations have shown that the nearby unlined Albany City Landfill, which was opened in 1969, has contributed both organic and inorganic contaminants to the Pine Bush aquifer. The lined Albany Interim Landfill was designed in a manner intended to protect groundwater integrity in the surrounding Pine Bush region. Groundwater contamination on the scale of the area of the Albany City Landfill can be difficult to remediate. Remediation of smaller commercial sites with contaminated groundwater is a somewhat more tractable problem. This field trip provides an opportunity to visit the Pine Bush, the Albany Interim Landfill, the Albany City Landfill, and a small commercial site (Stewart's Shop #182) that is currently undergoing groundwater remediation.

B8: ENVIRONMENTAL TECHNOLOGY AND PRESERVATION: THE PINE BUSH, LANDFILLS, AND GROUNDWATER INTEGRITY

STOP 1: Albany Interim Landfill
Access to the landfill is restricted. Call Landfill Technologies, Inc. (518-674-8694) in West Sand Lake, New York, to arrange a tour of the active and closed landfill areas.
ALBANY INTERIM LANDFILL The Albany Interim Landfill (AIL) covers an area of approximately 12 acres on the west side of Rapp Road in the City of Albany (Hansen, 1995). The AIL was constructed in the early 1990s with a double composite liner. The closed Greater Albany Landfill and the New York State Thruway lie to the south. A residential trailer park is located several hundred feet to the north. The Pine Bush Preserve borders the AIL to the west. Landfill service buildings and Rapp Road lie to the east. Figure 5 shows the approximate location of the AIL relative to the surrounding properties. The AIL is operated by Landfill Technologies, Inc. (LTI) of West Sand Lake, New York. In 1991, a program of biostabilized solid waste placement was proposed at the AIL. The program began with a pilot project in 1989.

STOP 2:Pine Bush Preserve and Albany City Landfill
STOP 2: Albany Pine Bush Preserve The Albany Pine Bush Preserve is open to the public. Sign in at the box near the entrance. We will walk generally east, pausing atop and between dunes to note the morphology and vegetation, eventually ending up at the west end of the closed Albany City Landfill. On the way, we will pass a monitoring well that is most likely GW-lD, the upgradient well installed by Engineering-Science in 1990. After looking at the landfills from this different perspective, we will make our way back through the Pine Bush to the vehicles.
ALBANY CITY LANDFILL
The Albany City Landfill (the landfill) covers approximately 80 acres of the Pine Bush. The landfill is located on the north side of the New York State Thruway between Rapp Road, the Conrail railroad tracks, and the Pine Bush Preserve. The landfill has been capped and permanently closed since 1994.
The landfill is of a relatively simple design: it is unlined, it has no leachate collection system (Malcolm Pirnie, 1988), and it is believed to be a surface waste pile rather than an excavated pit refilled with waste (Engineering-Science, 1992). During its years of operation, the landfill was filled using conventional sanitary landfilling techniques of compaction and daily covering of waste. Methane and leachate were not extracted during operation. Methane extraction wells and automatic burners were installed in 1991 after methane migration toward the south (under the Thruway) was discovered.
The landfill began operations in August 1969. It was operated by a private company under contract to the City of Albany until 1974, when the Albany Department of Public Works assumed operational responsibility. At the time of the transfer of responsibility, weight scales were installed and the City began to keep records of the incoming waste. Until that time, the waste had been largely unrecorded and uninspected. It is suspected that during the 1969-74 period and potentially until the 1980s, numerous area industries had disposed of various amounts of industrial and hazardous wastes at the landfill (Malcolm Pirnie, 1988; Engineering-Science, 1992).
Beginning in 1983, a portion of the waste brought to the landfill was used as fuel for the ANSWERS Refuse-Derived Fuel (RDF) plant located on Sheridan Avenue in Albany. Fly ash from the incinerator at the ANSWERS RDF plant was brought to the landfill for disposal (Malcolm Pirnie, 1988). Between 1983 and 1987, approximately 203,265 tons of fly ash were disposed of at the landfill. In addition, approximately 343,143 tons of municipal and other waste were deposited at the landfill during the same period (Engineering-Science, 1992). The municipal and other wastes brought to the landfill for disposal included bypassed solid waste (waste not used as RDF), excess RDF, petroleum-contaminated soil, picked material (unshreddable material removed during RDF processing), and ferrous material (Malcolm Pirnie, 1988), plus pharmaceutical wastes, iodine/soil wastes, and asbestos (Engineering-Science, 1992). The landfill began accepting petroleum-contaminated soil in 1987 (under the approval and recommendation of the New York State Department of Environmental Conservation, or NYSDEC), primarily for use as daily cover material; the landfill accepted approximately 14,000 tons of petroleum-contaminated soil in 1987 (Malcolm Pirnie, 1988).
Closure of the landfill began in 1982 under a phased approach. In 1985, the City of Albany signed a NYSDEC Order of Consent for the final closure of the landfill. In 1986, the City of Albany proposed an expansion project of the existing landfill to facilitate and expedite the closure process (Malcolm Pirnie, 1988). The expansion was approved by NYSDEC in 1989 (Engineering-Science, 1992), which resulted in the construction of the Albany Interim Landfill during the early 1990s.

STOP 3: Brandywine Stewart's Shop
The site is a convenience store and gas station. The remediation shed is closed to the public. Please do not take up customer parking spaces or block customer access to the store or gas pumps.
STEWART'S SHOP #182
The volatile organic compounds benzene, ethylbenzene, and toluene, which were detected at relatively low concentrations in groundwater at the Albany City Landfill in 1990, are commonly found as groundwater contaminants at sites that have experienced subsurface gasoline spills. The volatile natures of these and many other compounds typically found in gasoline offer a means of remediating, or cleaning up, the contaminated groundwater by encouraging volatilization, or evaporation, of the compounds. One method of encouraging volatilization of compounds is to pump contaminated groundwater through an air stripper. This remediation method is being used at Stewart's Shop #182, a small site on South Brandywine Avenue in Schenectady, New York (Figure 8).
The following information is summarized from Passaretti Geological & Environmental Consultants, Inc. (1991).
Groundwater Study
Stewart's Shop #182, a convenience store and gas station, is located at 100 South Brandywine Avenue in Schenectady, New York. In 1991, three underground gasoline storage tanks and one underground waste oil tank were removed from the site as part of a tank upgrading program. Petroleum-contaminated soil was encountered during the tank removal. Approximately 250 cubic yards of soil were removed from the former tank pit for offsite disposal. New underground storage tanks were installed in a different part of the site. The site had reportedly been a Stop & Go Station prior to being a Stewart's Shop. The contiguous site to the northeast had also reportedly been a gas station. The NYSDEC representative requested completion of a groundwater study at the site.

B9: GEOLOGY AND MINING HISTORY OF BARTON MINES CORPORATION, GORE MOUNTAIN MINE
WILLIAM M. KELLY
Rm. 3140 Cultural Education Center
wkelly@museum.nysed.gov
MARY LOUISE HILL
Temple University
Philadelphia, PA 19122-2585
mlhill@astro.ocis.temple.edu
This trip proceeds from Union College to the former Barton Garnet Corporation mine near the summit of Gore Mountain, New York. For 105 years, this was the site of the world's oldest continuously operating garnet mine and the country's second oldest continuously operating mine under one management.
The Barton Mines Corporation open pit mine is located at an elevation of about 800 m (2600 ft) on the north side of Gore Mountain (Fig.l ). The community at the mine site is the highest self-sufficient community in New York State. It is 16 km (10 mi) from North Creek and 8 km (5 mi) from NY State Route 28 over a Company-built road that rises 91 m (300ft) per mile. This road, like others in the vicinity, is surfaced with coarse mine tailings. About eleven families can live on the property. The community has its own water, power, and fire protection systems. On the property are the original mine buildings and the Highwinds Inn, built by Mr. C.R. Barton in 1933 as a family residence. The Inn is now privately leased from the Corporation and operates 10 months per year. It offers a four-bedroom lodge, a four star dining room, cross-country skiing and fantastic views of the Siamese Wilderness Area.
The garnet is used in coated abrasives, glass grinding, metal and glass polishing, and even to remove the red hulls from peanuts. Paint manufacturers add garnet to create non-skid surfaces and television makers use it to prepare the glass on the interior of color picture tubes prior to the application of the phosphors. Barton sells between 10,000 and 12,000 tons of technical-grade garnet abrasive annually. About 40% of the company's shipments are to foreign countries. All current U.S. production of technical-grade garnet is limited to the Barton Mines Corporation. The product is shipped world wide for use in coated abrasives and powder applications (Austin, 1993a,b).
Garnet has been designated as the official New York State gemstone. Barton produces no gem material but collectors are still able to find rough material of gem quality. Stones cut from Gore Mountain rough material generally fall into a one to five carat range. A small number of stones displaying asterism have been found. Garnets from this locality are a dark red color with a slight brownish tint. Special cutting schemes have been devised for this material in order to allow sufficient light into the stone.

B9: GEOLOGY AND MINING HISTORY OF BARTON MINES CORPORATION, GORE MOUNTAIN MINE

STOP 1. Barton Garnet Mine
HISTORY
The early history of the Barton garnet mine has been compiled by Moran (1956) and is paraphrased below. Mr. Henry Hudson Barton came to Boston from England in 1846 and worked as an apprentice to a Boston jeweler. While working there in the 1850's, Barton learned of a large supply of garnet located in the Adirondack Mountains. Subsequently, he moved to Philadelphia and married the daughter of a sandpaper manufacturer. Combining his knowledge of gem minerals and abrasives, he concluded that garnet would produce better quality sandpaper than that currently available. He was able to locate the source of the Adirondack garnet stones displayed at the Boston jewelry store years before. Barton procured samples of this garnet which he pulverized and graded. He then produced his first garnet-coated abrasive by hand. The sandpaper was tested in several woodworking shops near Philadelphia. It proved to be a superior product and Barton soon sold all he could produce.
H.H. Barton began mining at Gore Mountain in 1878 and in 1887, bought the entire mountain from the State of New York. Early mining operations were entirely manual. The garnet was hand cobbed (i.e. separated from the waste rock) by small picking hammers and chisels. Due to the obstacles in moving the ore, the garnet was mined during the summer and stored on the mountain until winter. It was then taken by sleds down to the railroad siding at North Creek whence it was shipped to the Barton Sandpaper plant in Philadelphia for processing. The "modern" plant at Gore Mountain was constructed in 1924. Crushing, milling, and coarse grading was done at the mine site. In 1983, the Gore Mountain operation was closed down and mining was relocated to the Ruby Mountain site, approximately 6 km (4 mi) northeast, were it continues at present.

B10: GROUNDWATER AQUIFERS OF THE UPPER MOHAWK VALLEY
PHILIP C. HEWITT
DEPARTMENT OF EARTH SCIENCES
SUNY COLLEGE AT BROCKPORT
BROCKPORT, NY 14420-2936
Much of the groundwater used by the city of Schenectady and the several smaller communities in the near vicinity comes originally from the Mohawk River via gravel aquifers lying just below or at the present surface. In addition to the city itself, the towns of Niskayuna, Rotterdam Junction and the Scotia-Glenville area also use this major primary source (Figure 1). Of course, other smaller sources exist, including the bedrock sandstones and shales (the Middle Ordovician Schenectady Formation) and surficial but small perched sand and gravel deposits adequate for household supplies with volumes that range from 1.5 to perhaps as much as 10 gallons per minute for a reasonable period of time. The Mohawk River, however, provides millions of gallons of clean fresh water each day from gravel aquifers through which the less than desirable river water flows and is, as a result, cleaned to a remarkable degree.
The basic study of the area was done by Simpson (1949) and by Winslow et al. (1965) as well as several other authors. The present study, primarily in the Rotterdam Junction Aquifer (Figure 1), builds upon their work and corrects some basic misconceptions regarding gravel aquifers of this type. It was supported by the Schenectady Chemical Company, now Schenectady International, and was used in litigation designed to protect their own and the town of Rotterdam Junction's water supply. The matter became important because the gravels were being mined and the aquifer was in danger of total removal (Figure 2). The vice-president of the company at that time (Clinton P. Braidwood) provided a drill rig and crew for my exclusive use and hired me as a consultant to study the aquifer fully. Dr. Robert Yunick, the present vice-president, continued the effort and now that litigation has ended successfully, has given me permission to publish the study. The town of Rotterdam Junction now owns the property in question in that area and James Constantino, the present town supervisor, has given permission for our entry to that particular site and has permitted our visit.

B10: GROUNDWATER AQUIFERS OF THE UPPER MOHAWK VALLEY

3.1 STOP 1 at L&M Motel. Discuss aquifer location.
THE SCHENECTADY AQUIFER
These gravel deposits are located in an area known as the Great Flats and are found along the south bank of the Mohawk River over an area a few hundred feet wide and less than one-quarter of a mile in length. The L&M Motel lies on top of the easternmost extent of that aquifer. West of the Schenectady Rotterdam #5 Well Field is Lock #8, but it is Lock #7 which actually controls the level of the water in the River (called the Barge Canal) at that point. As will be shown, the locks on the Mohawk River actually control the flow of water into these gravels.
The quality of the Mohawk River water is dramatically changed after it enters the gravels, which have small amounts of sand and clay in the interstices. As a result, water pumped at the Schenectady and Rotterdam #5 Well Field is cleaned and requires only a small amount of chlorination and relatively minor treatment to make it palatable and highly potable. Of course, it is an area in delicate balance. On an early occasion during the construction of the motel, some contamination did in fact occur but it was rapidly ended and there appears to have been no problem since that time. Any construction or even contamination from the recently built mall on Campbell Rd. (Rotterdam Square Mall), or the recently closed gasoLine station (Mobil) could also endanger these water supplies. Furthermore, the water level in the Mohawk River depends upon the lock levels for each of the aquifer portions of these gravels.

STOP 2. Continue discussion of aquifer location.
This is source of Schenectady City Water. Note Rotterdam Town Wells #5 District is in same well field. Discuss the aquifer itself and probable environmental concerns.

STOP 3 Park. Discuss source of water here.

Note bedrock on this road is Schenectady formation.

STOP 4 Old Kellam-Schaffer pit.
Discuss Rotterdam Junction Aquifer. Note groundwater elevation differences. Note surface till. Note gravel and clay and calcium carbonate blocking pores. Discuss pumping situation and excavation problems.
THE ROTTERDAM JUNCTION AQUIFER
By far the largest and most vulnerable of the gravel aquifers is the one that provides the water supply for the town of Rotterdam Junction and its main industry, Schenectady International. The length of this gravel aquifer is over 11,000 ft. and it varies from a few hundred to over a thousand feet in width. The gravel is typically a clean pea gravel, but also has a reasonable quantity of sand and minor clay. Thicknesses are quite variable but primarily the best gravels are as few as ten to fifteen to over forty feet thick in much of the length. The most interesting part of the problem lies in the fact that this aquifer is also a valuable economic resource. Its first appearance was in the Kellam-Schaffer Pit which we will visit on Stop 4. Here gravel was mined for many years. Two wells in this area tap the aquifer and for years provided water for the function of the Rotterdam Junction Chemical Plant which had (and still has) need for a plentiful supply (at least 2000 gallons per minute) of clean water for its operation. Later, others purchased the pit and expanded the quarrying, leaving a large and deep pit (Figure 2). The question of the value of the gravel versus the value of the water produced nearly thirty years of litigation, mining, periods in which mining was stopped legally, and continual study to learn everything we could about the aquifer in order to do all we could to prove its vulnerability and the probable loss of clean water with the loss of the aquifer to mining. Finally, thanks to Schenectady International, the aquifer area in the now much enlarged pit belongs to the town of Rotterdam

Note Schenectady International Plant at NE location.

STOP 5. Pump House #3 on left side opposite Post Office.
Discuss pumpage of well and the well development. Continue aquifer discussion.

STOP 6. Discuss Lock #9 and Lock System in general.

Field Trip Guide for the 68th Annual Meeting of
the New York State Geological Association
edited by
Alan I. Benimoff
Anderson A. Ohan
Hosted by:
Department of Applied Sciences
The College of Staten Island/CUNY
Staten Island, NY 10314
This guidebook was published by the New York State Geological Association. Additional copies may be obtained from the Executive Secretary of the NYSGA:
Dr. William Kelly
Executive Secretary
New York State Geologic Survey
Room 3140 Cultural Educational Center

A1: EARLY JURASSIC DIABASE SHEETS AND BASALT FLOWS, NEWARK BASIN, NEW JERSEY: AN UPDATED GEOLOGICAL SUMMARY AND FIELD GUIDE1996 A1
JOHN H. PUFFER
Newark, NJ 07102
JONATHAN HUSCH
Department of Geological and Marine Sciences
Rider University
Lawrenceville, NJ 08648-3099
Many important features of the early Jurassic igneous rocks exposed in the northern and central Newark Basin can be examined at the stops detailed below and located in Figures 1 and 2. The narrative preceding the road log and site descriptions is an update of one presented by Puffer and others (1992) and focuses on two aspects of the igneous activity that are the subject of considerable ongoing research. Part One - The PRHL and Other Diabase Sheets reviews the petrogenetic processes responsible for producing the rock compositions found within the sheets. In particular, evidence is presented that low density, late-stage granophyric magmas, produced by the olivine-absent crystal fractionation of an Eastern North America (ENA) quartz-normative high-titanium tholeiite (HTQ) magma, migrated laterally and vertically to the highest structural levels within any given sheet. In addition, each sheet apparently differentiated as a relatively closed system with little, if any, of the residual magmas reaching the surface flows of the Watchung Basalts. Part Two - The Watchung Basalts is a review and discussion of the geochemical data showing that the youngest of the three basalts formations, the Orange Mountain Basalt, is part of a huge chemically uniform HTQ igneous province and appears to be largely unchanged by fractionation from its mantle source, either an undepleted subcontinental lithosphere or a slightly enriched lithosphere produced by previous subduction events throughout the Paleozoic. The overlying basalt formations, the Preakness and Hook Mountain Basalts, are much more chemically diverse and contain high-iron (HFQ) and low-titanium (L TQ) quartz-normative ENA magma types derived from mantle sources chemically modified or distinct from the HTQ source.

A1: EARLY JURASSIC DIABASE SHEETS AND BASALT FLOWS, NEWARK BASIN, NEW JERSEY: AN UPDATED GEOLOGICAL SUMMARY AND FIELD GUIDE1996 A1

View Site: Laurel Hill
Due to the realities of traffic congestion and aggressively enforced trespassing laws throughout the New York City area, Laurel Hill is one of several excellent sites that we will not be able to stop at. But this exposure is at least clear enough to see through the bus windows.
Laurel Hill is an almost completely exposed early Jurassic volcanic neck, consisting of three concentric zones (Puffer and Benimoff, in press). The diverse chemical composition of Laurel Hill diabase overlaps each of the major eastern North American (ENA) Jurassic diabase types. Zone 1 is an irregular, heterogeneous, border-zone characterized by chemistry resembling the low-Ti-quartz-normative type (LTQ) ENA diabase but is interpreted as an alteration product of high-Ti-quartz-normative type (HTQ) diabase. Dilution of HTQ magma with hydrothermal sericite, and with plagioclase and pyroxene that accumulated during fractionation, has reduced the TiO2 content of Zone 1 from HTQ (1.1 percent) to LTQ levels (<0.9 percent). Localized assimilation of Passaic Formation siltstone is recognized by an enrichment of Zr in some Zone 1 samples. Zone 2, the intermediate zone, is characterized by chemistry typical of HTQ-type diabase. Zone 3, the interior zone, resembles the HFQ-type (High-Fe-quartz-normative) ENA diabase and is interpreted as an HTQ fractionation product.

Observe the Palisades sill on the east
Observe the Palisades sill on the east exposed as the north-south ridge in the background.

Observe upper portions of the Palisades sill on the left.
The upper contact is hidden behind vegetation and retaining walls.

Observe the vertical leucocratic dikes
Observe the vertical leucocratic dikes cutting through black Palisades diabase. The relatively thick dikes are composed of trondhjemite while the relatively thin dikes are albatite and calcite. They are described by Benimoff and others (1989) and are interpreted as fusion products of sodic Lockatong argillite host rock. They have a chemical composition similar to the host rock.

Observe olivine zone of Palisades Sill
Follow park road to the north; observe olivine zone of Palisades Sill on left recognized as an eroded out deeply altered cut at the base of the diabase slope. Stopping on the park road is strictly forbidden, but if you park at the entrance to the park the olivine zone is only a short walk.

Observe irregular lower contact of the Palisades Sill.
Observe irregular lower contact of the Palisades Sill with the Lockatong Formation.

Observe additional exposures of the conformable Lockatong/Palisades contact on the left

STOP 1. Lower Contact Of Palisades Sill With Lockatong Hornfels
Permission From The Palisades Interstate Park Commission To Stop And Collect Along The Road Is Required.
After admiring the view of the Hudson River and Manhattan Island, walk south from the parking lot along the road to the boat launch, then up the stone steps, through the tunnel under the road, and out onto road level. Walk north along the contact of the lower chilled zone with hornfels of the Lockatong Formation. According to Gorring and Naslund (1995), the fine-grained diabase chilled zone in the Fort Lee area consists of about 1-2 percent olivine (Fo68-78), 35-55 percent augite, 1-2 percent orthopyroxene (En75-80), and 35-55 percent plagioclase (An65-70; Walker, 1969). The pyroxene-dominated (along with plagioclase), tholeiitic-trend fractionation of this HTQ-type parental magma culminated in the development of a 33 m-thick granophyre layer, or sandwich horizon (Shirley, 1987), 50-100 m below the upper contact of the 330 m-thick sheet. Because this section of the PRHL megasheet is quite conformable, there appears to be little in the way of density driven lateral migrations of residual magmas and nearby sections through the Palisades contain very similar distributions of rock types (Husch, 1990). Some thin leucocratic veins and dikes of quartzofeldspathic material cut the diabase along the road at this locality. As discussed in Part I, these may have multiple origins.
The 3-4 m-thick OZ is exposed approximately 15 m above the road level and is exposed at road level 0.1 mile east of the entrance to the park (mile 30.8). At this locality the lower contact of the OZ is somewhat gradational, although the upper contact is quite abrupt, with olivine modes falling from over 20 percent to zero within less than one meter (Gorring and Naslund, 1995). At other localities along the Hudson river, both the upper and lower contacts of the OZ can be equally sharp (Walker, 1940; Gorring and Naslund, 1995).
Although originally thought by Walker (1969) to be the result of in situ gravitational crystal settling from a second pulse of Palisades magma that produced most (if not all) of the residual, granophyric compositions found higher up in the sheet, recent studies by Rusch (1990, 1992) and Gorring and Naslund (1995) indicate that this interpretation is incorrect. Rusch (1990, 1992) showed that olivine removal is inconsistent with the geochemical fractionation trends observed for the PRHL megasheet (see Part I) and that there are large-scale features of the OZ that suggest it was a separate olivine-rich intrusion into an already formed, although still largely molten, PRHL sheet. Gorring and Naslund (1995), on the other hand, believe the OZ to have formed as part of the initial injection of the RTQ parent (or at least within 5 years of that event) and that the olivine accumulation took place prior to or during the injection sequence. Based upon the distribution of olivine within the OZ and its composition (Fig. 13), Gorring and Naslund (1995) propose a mechanical sorting of olivine by a flow differentiation mechanism, a process also suggested by Rusch (1990).
Beneath the lower contact of the Palisades are contact metamorphosed buff-colored arkoses and platy and laminated siltstones. These metasediments have been described by Olsen (1980) and correlate with other Lockatong Formation exposures to the south. The pelitic layers, in particular, have been affected by thermal metamorphism and have been converted into black hornfels consisting of biotite and albite with minor analcime, diopside, and calcite, or to green hornfels consisting of green diopside, grossularite, chlorite, and calcite with minor biotite, feldspar, amphibole, and prehnite (Van Routen, 1969).
Porphyroblasts of pinite after cordierite commonly occur as small green spots in the black biotite-albite hornfels (Miller and Puffer, 1972). Large tourmaline porphyroblasts and even larger green spherical structures, up to 4 cm across, composed largely of clinozoisite, are less common in the hornfels, but are known from several other hornfels localities in the Newark and Culpeper Basins.

STOP 1A (Optional). Upper Contact Of Palisades Sill
Along Westbound Interstate 95 (Local Lanes). Stopping Along The Highway Other Than For Emergencies Is Illegal In New Jersey. The Police Will Ask You To Leave Immediately (If You Haven't Been Arrested Already).
This rare exposure of the upper contact of the Palisades is visible on both sides of the highway. The chilled margin is almost identical in composition, mineralogy, and texture to that found at the lower contact (Stop 1). Of course, no upper analog to the OZ is seen. Overlying the upper contact are hornfels of the Lockatong Formation, again similar to those found beneath the lower contact. The contact is highly conformable at this locality with only minor cross cutting "steps" visible; a few minor faults also have offset the contact. In at least one instance, apparent cooling cracks have been filled in with overlying sediments, producing a sedimentary dike structure. Other fractures in the upper contact zone contain copper mineralization and calcite fillings.
As one walks east towards the viaduct, more interior portions of the sheet are exposed and grain size increases, as does the amount of granophyric material. Eventually, pods of pegmatitic granophyre are found within a finer-grained, less differentiated diabase. Looking south across the highway at the opposite cliff (now sheathed in metal netting to keep loose boulders from faIling onto the highway) it is possible to see a number of leucocratic dikes running vertically across the face. Benimoff and others (1989) described these dikes as being trondhjemitic in character and concluded, on the basis of geochemical data, that they represented the late-stage injection of anatectic melts, derived from country rock xenoliths, into cooling fractures.

Exposure of Orange Mountain Basalt is on the left
Continue west across valley underlain by Jurassic red-beds of the Passaic Formation. Exposure of Orange Mountain Basalt is on the left with a well defined flow contact identified by an undulating erosion surface, and the contrasting textures of the vesicular upper entablature of the lower flow and the relatively massive lower colonnade of the upper flow.

Lower contact of Preakness Basalt on the right.
Most of the actual contact has been recently hidden by a new retaining wall and some landscaping but Feltville Formation siltstones exposed here have been thermally metamorphosed by the extrusion of one of the thickest flows of flood basalt anywhere on earth. The contact metamorphism has converted the otherwise consistently red siltstone into a gray layer within 5 meter of the contact and a dark gray hornfels within 1 meter of the contact. The thickness of the lower flow is about 150 m, comparable to the thickness of the Grand Ronde flow of the Columbia River Basalt and thicker than almost any flood basalt.

Note vertical strike-slip faults through the Preakness Basalt
Note vertical strike-slip faults through the Preakness Basalt defined by eroded fault gouge. The fault planes curve below the Preakness flow and do not seem to penetrate into the underlying Feltville Formation. Apparently shearing stresses were absorbed by plastic flow of unlithified Feltville sediments. Similar strike-slip faults are exposed at each of the several trap-rock quarries cut into Orange Mt., Preakness and Hook Mt. basalts in New Jersey.

Vertical jointing of the lowest of the five Preakness flows
Note the very closely spaced vertical jointing of the lowest of the five Preakness flows. A set of tectonically generated vertical platy-prismatic joints have been superimposed onto the vertical polygonal cooling joints, probably along incipient planes of weakness opened during cooling. The joint patterns have been described and their origin has been discussed by Puffer and Student (1992) and by Faust (1978).

The discontinuous exposure of the lower flow of the Preakness Basalt on the right
The discontinuous exposure of the lower flow of the Preakness Basalt on the right was a virtually uninterrupted exposure 6 miles long during highway construction in 1987, and afforded close inspection and sampling (Puffer, 1992). The chemistry and texture is uniform although there is a slight change in composition across the lower colonnade / entablature contact. The upper contact of the flow is clearly define d by a layer of ferruginous siltstone. The chemistry of the lower flow is the most highly fractionated of the 5 Preakness flows. The least fractionated flows are the thin upper flows (flows 3,4 and 5) which have typical LTQ compositions.

Observe the variations in jointing of Preakness basalt
Observe the variations in jointing of Preakness basalt exposures on the right and the strike slip fault planes.

STOP 2. Preakness Basalt
The view to the south includes the Orange Mountain basalt of the First Watchung Mountain in the background and the valley eroded into Early Jurassic Feltville Formation red beds in the foreground. While examining the Preakness note:
1. The very uniform medium grained texture consisting largely of plagioclase and pyroxene with only minor glass or mesostasis.
2. The large flat widely spaced joint plains in strong contrast to the very closely spaced platy prismatic joints exposed along 1-78.
3. The long curved but subhorizontal step-like parallel structure on the joint surfaces. They are interpreted as the kind of boundaries that join crack segments described by DeGraff and Aydin (1987). The cracks propagate downward through layers of freshly hardened basalt in the entablature as the upper crystallization front of the flow advances down into the largely liquid crystal mush below.
4. The strike-slip fault plain eroded into the Preakness. Note the horizontal striations on the slickenside surfaces.
5. The occurrence of a few rare and small shapeless basaltic pegmatites located between crack segment boundaries, and the occurrence of discontinuous, very thin, vesicular, basaltic pegmatite layers at the crack segment boundaries as described by Puffer and Horter (1993). Although the crack segment boundaries are well defined at this exposure, the pegmatites are not particularly well developed. The size and occurrence of basaltic pegmatite is rather unpredictable but seems to be restricted to unusually thick lava flows. Probably the largest pegmatite layer found in any ENA basalt, as of 1996, was recently mapped by Richard Volkert of the New Jersey Geological Survey at a construction site in the Preakness basalt located near the Chimney Rock quarry. The pegmatite in addition to being huge is highly fractionated with only 2% MgO and as much as 3% TiO2. It also contains considerable glass, but for more details we will wait for Volkert's report.

The Weldon Trap Rock Quarry
The Weldon Trap Rock Quarry cut into Orange Mountain basalt is on the left. The basalt here is mineralized with zeolites and prehnite that lines huge vugs over 2 m across. The quality of the zeolites and prehnite is easily of museum grade but access to the quarry was denied. Chemical analyses of several basalt samples collected here are reported by Puffer (1992). Each of the three Orange Mountain flows are exposed in the quarry.

STOP 3. Orange Mountain Basalt
Walk to the monument to General George Washington at the flag pole. The view to the south-east is largely a valley eroded into Triassic red-beds. This entire view area was once occupied by Orange Mountain flood basalt. The Atlantic Ocean (Raritan Bay) is 15 miles to the south/east and can be seen on a clear day. Picnic tables and drinking fountains are available but the rest-room facilities have been closed as a cost cutting measure in defiance of the laws of nature.
The Orange Mountain Basalt exposed near the flag pole is much finer-grained than typical of the Preakness. The basalt here contains common amygdules composed of chlorite and less commonly by quartz. The columnar joint pattern is reasonably clear but lacks the sharp flat surfaces typical of Preakness exposures or the greater degree of clarity at greater depths into Orange Mountain entablatures. The irregular columnar joint pattern and amygdule content are evidence of close proximity to a flow top.

Chimney Rock Quarry in OMB on right.
This is probably the largest active trap-rock quarry in the Watchung basalts. In addition to a spectacular array of beautiful prehnite and zeolites, particularly heulandite and some of the best natrolite anywhere on earth, there is abundant native copper mineralization in the first Orange Mountain basalt flow and in the Passaic red-beds within a meter of the contact. Sheets of native copper measuring as much as a foot across are easily collected; however, permission for us to collect today was denied. Basalt flow contacts are clearly displayed with very thin layers of red-bed rock between the flows. A description of the mineral collecting here was written by Sassen (l978).

Cross North Branch of the Raritan River.

View to SW of the Cushetunk Mountain diabase (CMD).
Good view to the southwest (left) of the forested ridge, rising approximately 500 feet above the surrounding plain of the Newark Basin, formed by the northeastern arm of the Cushetunk Mountain diabase (CMD).

STOP 4. Fault Zone In Granophyric Rock
Fault Zone In Granophyric Rock of the Cushetunk Mountain Diabase West End of Round Valley North Dam, Lebanon, NJ.
Round Valley Reservoir was filled in the late 1960's and is an important source of water for many municipalities in northern and central New Jersey. It is surrounded on three sides by the arcuate ridge of the CMD. The northwest quadrant of the reservoir is bounded by Precambrian metamorphic rocks, presumably of Grenville age.
Initial geochemical data by Puffer and Lecher (1979) indicated that the CMD chilled margin composition was a quartz normative, high-iron (HFQ) ENA type. However, more recent analyses by Keely and Husch (1993) show that the CMD chilled margin composition is very similar to all other Newark Basin HTQ chills and flows. Keely and Husch (1993) also show that the composition of the interior of the CMD generally becomes more fractionated and granophyre rich as one progresses northward along the intrusion's northeastern arm (Fig. 14). This arm cross-cuts over 5000 feet of the Triassic sedimentary section, rising to within 3000 feet of the OMB, the presumed Early Jurassic paleosurface (Houghton and others, 1992). Reversals in the general fractionation trend, as is found for this stop location (Fig. 14), are believed to be due to post-intrusion normal faulting exposing deeper, less fractionated structural levels of the CMD within the footwall block (Keely and Husch, 1993).
The diabase at this locality is quite granophyric, although less so than the diabase found at the east end of the dam, and contains abundant pink alkali feldspar. Equally obvious at this exposure are numerous fracture surfaces on which well-developed slickensides are observed. Most surfaces indicate a nearly horizontal right-lateral motion, although a few surfaces suggest a normal oblique, right-lateral motion. Houghton and others (1992) map this fault zone as a normal oblique splay fault of the Flemington Fault Zone (Fig. 2). Based upon the geochemical data of Keely and Husch (1993), as much as 5000 ft of vertical offset may have occurred along the fault zone seen here between the footwall block to the west and the headwall block exposed on the opposite side of the dam to the east (see sample CMl, Fig. 14). Jakubicki and Husch (1995), utilizing two-dimensional Bouguer Anomaly modeling, confirmed the normal sense of the vertical offset, but suggested the throw was less, on the order of 1500-2000 feet. The gravity modeling of Jakubicki and Husch (1995) also confirmed the initial findings of Wofford (1962) that the CMD dips outward (Fig. 15) and has the general shape of a ring dike.

Crossing Prescott Brook. Round Valley South Dam on left.

STOP 4A (optional). Outcrops of Granophyre
At Northern End Of The Prescott Brook Diabase, Stanton, NJ.
Park along side of road immediately across from white house. Climb to top of hill on right.
The diabase at this locality is quite coarse grained and granophyre rich, with MgO concentrations as low as 1.5 weight percent (Keely and Husch, 1993). Approximately 1 km farther south (and structurally lower by approximately 1500 ft) the diabase composition is not quite as fractionated with an MgO content of approximately 3.0 weight percent (Houghton and others, 1992). Again, the chilled margin (not exposed here) composition for the Prescott Brook diabase (PBD) is typical ENA-HTQ type (Houghton and others, 1992). Keely and Husch (1993) proposed that the PBD was connected at depth to the adjacent CMD to the east, based upon their similar relationships between stratigraphic level of emplacement and composition (Fig. 14). This however, could neither be confirmed nor refuted by the Bouguer Anomaly modeling of Jakubicki and Husch (1995).
Running diagonally across the north-facing slope of the hill is an enigmatic 3 to 5 ft-thick layer that weathers more readily than the surrounding rocks, forming a prominent recess in the hillside. Two of the layer's more noticeable features are its broken, brecciated character and the presence of chevron-like fractures or folds across it. A number of origins have been suggested for this unit, none with any great conviction or certainty. Thus, its origins are unknown at this time and any and all suggestions or ideas, no matter how far-fetched, will be entertained.

Hill to left is western slope of the Round Mountain diabase (RMD
Hill to left is western slope of the Round Mountain diabase (RMD), a HTQ-derived, granophyre-rich intrusion located approximately one mile to the south of the CMD and PBD (Houghton and others, 1992). Gravity data suggests that it is connected at depth to the CMD (Jakubicki and Husch, 1995).

Cross over South Branch of the Raritan River.

Family Golf Center on right.
A fairly complete cross section of the Flemington dike (FD)was exposed for a few weeks in the foundation pit during the construction of the center's main building. Samples collected at that time were analyzed by Crohe (1996) for major and trace-element compositions. Significant contamination affects (see Part I), particularly adjacent to the eastern contact zone of the dike, were found.

Road crosses over the FD (now on left)
Road crosses over the FD (now on left) which continues to strike almost due south towards the upper contact zone of the Lambertville sill.

STOP 5. Float Boulders of Flemington Dike, Ringoes, NJ.
All Boulders At This Location Are On Private Property. Many Are In Yards Or Gardens. Please Ask For and Get Permission Before Examining Or Collecting.
Walk across road (west side) to wooded area just to the left of the gray house (Janet and George Holt, 39 Back Brook Road, Ringoes, NJ 08552). There are numerous pieces of FD float lying along the road; there are no known outcrops of the dike exposed at the present time. Please disturb the pieces on the property as little as possible and leave those in the yard and garden alone. Hand samples may be collected from float in the bushes on the east side of the road opposite the house.
All float pieces contain the same fine-grained diabase found along the entire strike length (approximately 7 miles) of the FD. The dike, which is approximately 50-100 feet wide, exhibits little textural or mineralogic variation. Although all samples of the FD have compositions very typical of the ENA-HTQ type (Crohe, 1996), probable wall rock contamination affects, such as elevated concentrations of Na2O, K2O, and Ba, and decreased concentrations of CaO, generally become more pronounced as the dike strikes northward towards shallower structural levels. This is not surprising given the fact that the FD traverses over 9000 feet of the Triassic sedimentary section between the Lambertville sill (the dike's source; Stop 6) and the Flemington basalt (Houghton and others, 1992), the OMB equivalent flow that the FD presumably feeds. According to Houghton and others (1992), the Flemington Basalt exhibits striking geochemical signs of contamination, with as much as 5 weight percent Na2O and 300 ppm Ba.

Cross over Flemington Dike.
Small pieces of float have been collected from south side of road. Dike strikes south up the hill to the right and intersects the stope-like structure of the Lambertville sill at crest.

Float from intersection of Flemington dike and Lambertville sill
Just beyond gray ranch house (23 Losey Road) on right a dirt road heads west along the crest of the hill. Approximately 0.3 miles up from Losey Road, float from the approximate intersection of the Flemington dike and the Lambertville sill contact zone can be collected. Compositions and textures are very similar to what can be found at Stop 5.

STOP 6. Diabase With Pegmatitic Granophyre
In The Stope-Like Structure Of The Lambertville Sill, Rocktown, NJ.
This stop is located along the eastern limb of the stope-like structure found in the central portion of the Lambertville sill (Fig. 2). The top of this structure is emplaced approximately 3000 feet higher in the stratigraphy than the adjoining northeastward striking arm of the sill. Consistent with the dynamic fractionation model where residual, fractionated magmas migrate to the highest structural levels within a sheet, Szemple (1996) found that all diabase samples collected from the stop-like structure are differentiated to some degree, containing between 2.9 and 5.6 weight percent MgO; no MgO-rich samples with elevated pyroxene modes are known. This makes the stope-like structure compositions complimentary to the mafic- (and pyroxene-) rich compositions found in sections at the Lambertville sill's southwestern and northeastern ends by Eliason (1986) and Roth (1988), respectively (Fig. 16). By combining these sections, a regional or sheet-wide mass balance is attained, although at any individual section a local mass balance is lacking.
At this particular locality, the diabase is fairly feldspathic with as much as 19 weight percent Al2O3 (Crohe, 1996). However, pods of pegmatitic granophyre, reminiscent of those seen at Stop 1A, are quite common within the host diabase. A more granophyric diabase can be seen in some of the float pieces located across the road and in float located on the other side of Route 31, approximately one mile to the west.
Finally, it should be reiterated here, that it does not appear that any of the residual, granophyric material, so common in this section of the Lambertville sill, was transported into the immediately adjoining Flemington dike or erupted onto the surface as part of the Flemington basalt. This indicates that the emplacement of the HTQ magma into the Flemington dike and its eruption as the Flemington basalt was completed prior to the internal differentiation of the PRHL sheet (as represented locally by the Lambertville sill). Otherwise, granophyric compositions resulting from that differentiation would be more common within the dike and flow.

A2: STRATIGRAPHY, STRUCTURAL GEOLOGY, AND DUCTILE- AND BRITTLE FAULTS OF NEW YORK CITY
Charles Merguerian
114 Hofstra University
Hempstead, NY 11550-1090
E-Mail: geocmm@hofstra.edu
Long the center of commerce and culture in the United States, Manhattan is an island around which many geologic units and structural features coalesce. Manhattan's underlying lithology and durable crystalline structure have enabled the construction of enormous towering skyscrapers rooted into glacially-sculpted Paleozoic and older crystalline rock. First studied by naturalists in the 1700's, and by geologists in the 1800's and 1900's, the bedrock geology of the New York City area was mapped in systematic detail beginning in the mid- to late 1800's by L. D. Gale, W. W. Mather and F. J. H. Merrill. Merrill, the senior author of the United States Geological Survey New York City Folio (#83) published in 1902, outlined the basic stratigraphic and structural framework that all succeeding geologists would test, promote, and expound upon.
Today's trip examines the Paleozoic bedrock geology and the ductile- and brittle faults of New York City. The trip consists of seven easily accessible localities ("stops") in Manhattan and the Bronx (Figure 1). All of the outcrop areas are located in public parks or road cuts which may be easily reached by car, bus, or subway. The seven localities are plotted on segments of the Central Park 7-1/2 minute quadrangle (Figure 2) and UTM grid coordinates are supplied with the stop descriptions. Thus, no detailed road log has been made for this trip. The field-trip stops have been chosen to best identify outcrops critical to my new interpretations of the bedrock geology of New York City, including the results of joint studies with J. E. Sanders that have provided evidence for post-Pleistocene uplift along the footwall of the Mosholu Parkway fault in the Bronx.
No road log. UTM coordinates are probably NAD27, so were not used. Instead, locations were taken from little insert maps.

STOP 1 - HARTLAND FORMATION IN RIVERSIDE PARK
UTM Coordinates: 585.95EI4515.35N northward to 586.35EI4516.10N, Central Park 7-112 minute quadrangle.
The Hartland Formation or upper schist unit (G - Oh) crops out in Riverside Park from West 75th Street northward to West 116 Street. Described here are exposures near West 90-91 Streets and West 82-85 Streets.
The northernmost outcrops consist of gray-weathering, well-layered and slab by to laminated, lustrous muscovitic schist containing interlayers of quartz-muscovite biotite granofels. Locally, 1 cm thick glassy quartzite interlayers and elliptical pods of recrystallized dark quartz occur. The prominent 2-3 cm scale layering results from original compositional variations and subparallel S1 + S2 metamorphic recrystallization. The metamorphic layering is parallel to N48°E, 65°SE axial surfaces of long-limbed F2 isoclinal folds plunging 60° into S28°E. A strong down-dip stretching lineation (L2) composed of quartz ribs and streaked mica lies within S2 and is deformed by F3 folds. The F3 folds are tight, south-plunging "s" folds with abundant shearing along their axial surfaces (S3 = N37°E, 78°SE). L3 intersection lineations and stretching lineations are parallel to F3 hinge lines which plunge 22° into S29°W and deform the L2 lineations. S3 is typically a transposition foliation with oriented mica and migmatite overprinting the older folds and related fabrics. Pre-, syn-, and post-D3 pegmatites are found throughout the area.
The southern outcrops of the upper schist unit are lithologically identical to the above except the layering is thicker (6-8 cm) and a laminated black-weathering, greenish-black biotite-amphibolite layer (1 m thick) occurs near West 82 Street. Together these outcrops illustrate the penetrative nature of F3 isoclinal folds with their shallow southward plunges. Apparently the NW-trending, shallow SW-dipping enveloping S2 metamorphic layering exerted a strong control on the orientation of F3 hinge lines despite the fact that significant transposition occurred during D3. The average orientation of S3 is N55°E, 75°SE with F3 hinge lines and sub-parallel L3 lineations plunging 20° into S40°W. (See Figure 6.) Late, open folds with axial surfaces trending N47°E, 90° are locally developed.
Several glacial features of interest are present here. The overall shape of the surface of the bedrock defines several roches moutonnees. Not only are the rock surfaces rounded and smoothed on a large scale, but grooves and striae are present as well. The trends of these show that the ice flowed across the Hudson River, from NW to SE, consistent with a multi-glacier model proposed recently by Sanders and Merguerian (1991, 1992, 1994a, b) and Merguerian and Sanders (1996c).

STOP 1B. Northern Limit of Stop 1

STOP 2 - CAMERON'S LINE AND THE HARTLAND AND MANHATTAN Fms
NEAR WEST 165 STREET. UTM Coordinates: 588.90E / 4521.41N, Central Park 7.5 minute quadrangle.
The Manhattan formation (G - Om) is exposed here in a large outcrop west of Riverside Drive. The Manhattan formation dominates, consisting of rusty- to gray-weathering, coarse-grained gneiss and schist with 2-15 cm interlayers of quartz-biotite-garnet-kyanite-sillimanite granofels. The rock contains porphyroblasts of kyanite +/- sillimanite and garnet (up to 1 cm). Outcrops 350 m to the north show more typical rusty-weathering colors and abundant aluminosilicates of G - Om, yet in November 1985, subsurface construction exposures to the east of Riverside Drive exposed muscovite-rich Hartland lithologies (G - Oh) cut by brittle faults. These exposures are typical of Cameron's Line, with intercalated lithologies of both bounding units found in close proximity and clear distinction blurred by D2 tectonic intercalation.
Structurally, at the south end of the outcrop, there is a clear example of a long-limbed intrafolial F2 reclined fold refolded by F3 "z" folds. Here, F2 folds an S1 biotite foliation and granitoid pods developed parallel to S2 (and/or S1) are folded by F3. S2 trends N54°E, 44°SE with F2 plunging 40° into S19°E and S4 trends N20°E, 75°SE with F3 axes plunging 42° into S10°W. Excellent examples of type-3 interference patterns (Ramsay, 1962) are found on the sloping north-facing portion of the outcrop. Cameron's Line passes above our heads as we stand in the core of a south-plunging F3 fold, exposing G -Om at street level. Hartland rocks crop out to the south and east.
Several glacial features of interest are present here. The overall shape of the surface of the bedrock defines several roches moutonnees. This particular rock knoll probably was a splendid example of a roche moutonee many years ago, but cannot be considered as such any longer. The diamond-drill holes along the rock face by the sidewalk indicate that the SE side of this knoll was blasted away to make way for the street and the sidewalk. Not only has the rock surface been rounded and smoothed on a large scale, but grooves and striae are present as well. The trends of these show that the ice flowed across the Hudson River, from NW to SE.

STOP 3 - ST. NICHOLAS THRUST AND CAMERON'S LINE
INWOOD HILL AND ISHAM PARKS UTM Coordinates centered on: 590.50E / 4525.00N, Central Park 7.5 minute quadrangle.
Inwood Hill Park is located in the extreme northwest corner of Manhattan Island. The park is bordered by Dyckman Street on the south, the Hudson River on the west, Spuyten Duyvil (Harlem Ship Canal) on the north, and Payson and Seaman Avenues on the east. Isham Park occupies the flat area northeast of Inwood Hill Park extending eastward to Broadway between Isham and West 214 Streets.
The area of Manhattan north of Dyckman Street is known as the Inwood section. Except for Inwood Hill Park, the region is underlain by the Inwood Marble marking the name-locality (originally called the Inwood Limestone by Merrill 1890). Isham Park contains near continuous exposure of the Inwood Marble (G - Oi). Several lithologies occur such as coarse-grained dolomitic marble, fine-grained calcite marble, foliated calc-schist, and marble containing siliceous layers and calc-silicate aggregates that stand in relief as knots on the weathered surface. The marble ranges from white- to blue-white to gray-white. Depending on the amount of impurities, it weathers gray or tan and produces a sugary-textured surface on outcrops which ultimately develops into a residual calcareous sand. In addition, the outcrops illustrate differential weathering with dolomite-silicate units standing in high relief and calcite marble forming depressions.
The Inwood trends N45°E, 73°SE and forms the eastern overturned limb of a large F3 synform which is cored to the west by the middle schist unit (G - Om) of Inwood Hill Park. Tight south-plunging F3 folds are locally developed. Older structures are not obvious but can be found (especially after, or during, a rain) as long-limbed F2 isoclinal folds. Abundant examples of boudinage of the siliceous and calc-silicate layers into lenses occur due to the marked ductility contrast between them and the surrounding marble.
Enter Inwood Hill Park following the path past the playground. The first (of two) prominent ridges is composed of kyanite-garnet gneiss and schist of the middle schist unit (G-Om) which is structurally separated from the Inwood Marble by the St. Nicholas thrust (not exposed here). Follow the path to where it curves around to the west side of the ridge and enters a valley underlain by a south-plunging F3 antiform which exposes tan weathering, gray-white Inwood Marble striking N40°E, and dipping 58°NW.
Along the path going north (up-slope) along the westernmost ridge, massive, brown-weathering, blackish amphibolite of the middle schist unit crops out. Rocks exposed on the ridge (G - Om) are massive muscovite-biotite-plagioclase-quartz-garnet-kyanite gneiss and schist with weathered kyanite+quartz+sillimanite nodules. The structure of the ridge is a south-plunging F3 synform overturned toward the northwest. The S3 foliation in the middle schist unit is related to F3 folds with axial surfaces oriented N41°E, 75°SE and south-plunging hinge lines. The F3 structures are superimposed on an older S2 metamorphic layering which trends N50°W, 25°SW. Atop the ridge, a few exposures of muscovitic schists that are strikingly "Hartland-ish" occur. If they are indeed Hartland rocks and not minor muscovite-rich zones in the Manhattan (which do occur, locally), a case may be made for skirting the top of the ridge with a klippe underlain by Cameron's Line.
Along the N-facing backslope of the western ridge, the contact between the middle (G-Om) and lower (Om) schist units (the St. Nicholas thrust) is exposed in a 20 m zone from beneath the Henry Hudson Bridge abutment to river level. Structurally beneath the middle schist unit a 0.5 m layer of mylonitic amphibolite is deformed by F3 folds. Unlike the amphibolite in the middle schist unit above, which contains subidiobastic hornblende, this amphibolite has been retrograded by intense shearing parallel to the S2 foliation. Green hornblende porphyroclasts are set in an anastomosing S2 foliation consisting of colorless clinoamphibole, biotite, and quartzose ribbons.
Directly beneath the bridge, where a dirt trail leads down to the river, a coarse-grained gray-white calcite marble with differentially eroded calc-silicate nodules is exposed at low tide. It is unknown whether the marble exposed at the low-tide mark is a "Balmville" interlayer in the lower schist unit (Om) or a faulted part of the Inwood Marble.
Physically above the marble exposure, the lower schist unit consists of biotite-quartz-plagioclase and kyanite with abundant garnet porphyroblasts. Here the lower schist unit contains an S2 mylonitic foliation composed of mm-scale ribboned and polygonized quartz with recrystallized reddish pleochroic biotite. Produced in the axial planes of F2 reclined folds, the S2 foliation strikes N45°E and dips 55°SE with a strong down-dip lineation plunging 50° in a S34°E direction. The thrust zone is structurally complex consisting of intercalated lithologies of the lower- and middle schist units together with mylonitic amphibolite.

STOP 4 - ST. NICHOLAS THRUST AND MANHATTAN Fm
IN ST. NICHOLAS PARK UTM Coordinates: 588.45E / 4518.28N northward to 588.75E / 4519.15N, Central Park 7.5 minute quadrangle.
The St. Nicholas thrust separates the middle schist unit (G - am) from the Inwood Marble (G- Oi) along the east edge of St. Nicholas Park situated west of St. Nicholas Avenue between West 129 and West 141 Streets. Excellent outcrops of the schist form the steep ridge of the park. The southernmost outcrops consist of rusty-weathering biotite- and muscovite-rich gneiss and schist with abundant alumino silicate nodules, interlayered biotite-quartz-garnet granofels, and thin amphibolite. The Inwood Marble is not exposed but, based on drill core data and geomorphology, underlies the lowland immediately east of the park.
Outcrops atop the ridge on St. Nicholas Terrace contain flattened alumino silicate layers folded by F3 folds. Northward, F2 isoclinal folds with subhorizontal axial surfaces are also deformed by F3 folds. S3 trends N30°E, dipping 70° SE and is locally warped by several generations of late crenulate and open folds.
A penetrative S2 mylonitic layering occurs at the northeastern most exposures in the park. Tight- to isoclinal F3 folds deform and locally transpose the S2 mylonitic foliation into parallelism with S3. In addition, the F3 folds deform pegmatite sills injected sub-parallel to S2 + S1, thin lit-par-lit foliated syn-D2 granitoids, alumino silicate layers, and quartz veins. Because of the combined effects of D2 and D3 the rocks are highly recrystallized and locally migmatitic.
The contact between the middle schist unit and the Inwood Marble is never observed but the presence of unusually penetrative S2 fabrics in the schist at the eastern edge of the park and the apparent absence of the lower schist unit together suggest that the St. Nicholas thrust may be marked by the abrupt break in slope to the east.

STOP 5 - ST. NICHOLAS THRUST AND THE MOUNT MORRIS PARK OUTLIER
UTM Coordinates centered on: 589.13E / 4517.25, Central Park 7-1/2 minute quadrangle.
The Mount Morris Park Outlier, a hill protruding above the Harlem Valley centered at West 122 Street and Fifth Avenue, consists of an erosional remnant of the middle schist unit (G-Om). The Inwood Marble (G - Oi) crops out on the Madison Avenue (east) side of the park. The marble is gray- to tan-weathering and contains schistose zones with layers and nodules of diopside+tremolite+quartz. The middle schist unit is composed of rusty- and locally, maroon-weathering, gray, gneiss and schist with kyanite layers, zones of porphyroblastic kyanite+garnet, and layers of biotite-quartz-plagioclase+ garnet granofels.
The overall structure of the park is a south-plunging klippe of the middle schist unit produced by the superposition of an F3 synform and a late, NW-trending synform. The klippe of G - am is terminated along its southern margin by a brittle fault (splay of the 125th Street fault?) exposed at street level trending N69°W, dipping 84°SW. Slickensides in the fault surface are oriented N70°W @ 22° clearly indicating a strike-slip movement sense although a component of reverse motion is suggested by faint dip-slip slicks and the presence of Inwood Marble to the south. Along the east-face of the exposure, the St. Nicholas thrust is found between the Manhattan schist and Inwood Marble and is marked by 10° truncation of lithologic layering and an early S1 foliation in the marble, extreme flattening, 2-3 cm scale annealed mylonitic layering, shearing and imbrication of lithologic units (including small tectonic slivers and interlayers of schist unit Om?), and quartz veins.
Developed during thrusting and deformed by F3 folds, the S2 enveloping surface is variable but on average trends N30°W, 20°SW and marks the axial surface of reclined and isoclinal folds found both above and beneath the St. Nicholas thrust contact. Disharmonic F3 folds of mylonite developed at the thrust contact are exposed at the northern edge of the klippe. They trend N32°E, 80°NW to 70°SE and plunge 23° into S25°W.

STOP 6 -BALMVILLE MARBLE AND LOWER MANHATTAN SCHIST UNIT
GRAND CONCOURSE AND THE CROSS BRONX EXPRESSWAY, BRONX.
UTM Coordinates: 591.65E / 4521.95N, Central Park 7.5 minute quadrangle.
An excellent exposure of the lower schist unit (Om) occurs west of the Grand Concourse in an overpass above the Cross Bronx Expressway (1-95). Here, fine- to medium-grained, massive but locally friable, tan- to brown-weathering schist and granofels is found interlayered on the scale of 3-4 m with calcite and dolomite marble containing 2-3 cm diopside+tremolite calc-silicate and siliceous layers. Massive Inwood Marble (G - Oi) occurs in the roadcut forming the south wall of 1-95 beneath the overpass. This locality, together with exposures described earlier in Inwood Hill Park (Stop 3) and a few other outcrops south of I-95 paralleling the Grand Concourse (C. A. Baskerville, personal communication), are interpreted as the autochthonous portions of the "Tippecanoe" Manhattan Schist.

STOP 7 - CAMERON'S LINE - BORO HALL AND CROTONA PARKS
, CROSS BRONX EXPRESSWAY. UTM Coordinates centered on: 593.00E / 4521.80N, Central Park 7-1/2 minute quadrangle.
Boro Hall Park in the Bronx is surrounded by East Tremont A venue on the north, Third Avenue on the west, Arthur Avenue on the east, and East 175th Street on the south. The last named also serves as the westbound service road for the Cross Bronx Expressway (I-95). This park is situated on an important subdivision of the metamorphic schistose rocks of the Bronx. On the 1971 edition of the Geologic Map of New York (New York State Museum and Science Service) places a queried dashed line through the center of the park as the contact between the New York City Group on the west from the Hutchinson River Group on the east. Seyfert and Leveson (1969) discuss the contact as a thrust fault and argue that it is on strike with Cameron's Line. Based on lithologic correlations, Baskerville (1982a, b, 1992) first identified the contact as Cameron's Line; Merguerian and Baskerville (1987) defined the structural relationships discussed below.
Along East 175th Street the outcrop nearest Third Avenue is a brown- to rusty-weathering, medium-textured, gray, biotite-muscovite schist of the middle schist unit (G - Om) containing several pegmatite dikes. The foliation strikes N40°E, and dips 70°SE. Test borings for the I-95 overpass near this locality indicate that marble occupies the Third A venue valley to the west. East of the middle schist unit is a soil-covered shallow swale, 30- to 40 m wide, that trends N40°E. The Hartland Formation (G - Oh) crops out to the east of the swale and also south of the expressway in Crotona Park (described below). The Hartland rocks are brown- to tan-weathering, gray muscovite-biotite-quartz-plagioclase-garnet schist and gneiss with granitoid sills and thick layers of greenish amphibolite.
The contact between the middle schist unit (G - Om) on the west and the Hartland Formation (G - Oh) is never exposed but presumably occupies the swale between the outcrops. Rocks on either side of the contact are highly flattened; as a result of recrystallization during D3, the microscope shows little evidence for mylonitization. Microscopically, brittle fractures are well developed in the minerals, suggesting the contact may be a brittle fault reactivating an older ductile contact. The contact between these units is known as Cameron's Line, a ductile fault separating allochthonous sequences of the Taconian Hartland and Manhattan formations.
Dr. Patrick W. G. Brock of Queens College, who took a class to this stop, collected specimens, and examined the rocks petrographically, detected a corroded grain of corundum that had been highly retrograded by higher-crustal-level metamorphic overprinting. Although it was not in contact with quartz and clearly had undergone retrograde reactions, the corundum discovery suggests that the rocks in this region had initially experienced metamorphism at least up to K-feldspar- sillimanite grade.
To the south of the Cross Bronx Expressway, in Crotona Park, Cameron's Line again separates schist, gneiss, and amphibolite of the Hartland Formation (G - Oh) on the east from westerly exposures of schist and gneiss of the middle unit of the Manhattan Schist Formation (Gam). The rocks are not found in direct contact but, similar to exposures to the north, are separated by a soil-covered interval. The Manhattan exposures are mylonitized, however, with shear folds and laminated textures well displayed.

A3: A SURVEY OF THE NATURAL AND URBANIZED SHORELINES ON LONG ISLAND, NEW YORK - A DILEMMA IN COASTAL MANAGEMENT
Manfred P. Wolff(l), Nicholas K. Coch(2), Robert W. Johnson(3)
(1) Geology Department, Hofstra University
(2) Department of Geology, Queens College, CUNY
(3) Biology Department, Hofstra University
This trip will examine six stops on the barrier island beaches along the south shore of Long Island (Figure 1). Such beaches were probably first formed during the Pleistocene glaciation from eroded and reworked continental Cretaceous-Tertiary strata 100 Km. seaward of their present location. They were then gradually submerged and modified into shoals, lagoons, barrier islands and inlets by the current marine transgression. During the past 25,000 years of glacial melting and deposition the rising sea reached the outer edge of the glacial outwash and moraine deposits, perhaps 3-5 Km. seaward of their present location (Wolff, 1982). It is this newer source of Pleistocene glacial sediments that continue to undergo the transitory processes that modify them into the current coastal features. Ultimately, they will be eroded and deposited offshore, on the shoreface, and below wave base on the inner continental shelf--as the Holocene transgression continues.
We accept the concept of "barrier island migration" with the rising sea, and will provide evidence for it. This emphasizes the idea that the barrier islands have not been "drowned" but instead, continue to be preserved by progressive landward sand migration. This migration occurs during the shoaling associated inlet formation, and during the flooding and over wash deposition associated with the wave surge from major storms (Wolff, 1989).
Anthropogenic changes brought on by coastal habitation during this century have seriously curtailed the influence of these natural processes in maintaining the sporadic pattern of inlet formation and landward barrier island migration. Management philosophy has instead substituted a policy that now emphasizes mechanisms that attempt preservation of all the natural environments through coastal stabilization. While most of our field stops are on urban beaches, they are maintained by different levels of government (state, county, city and town) and the management policies may also differ. We will review the history of development (natural and urban) at each of these stops, examine the methods used for the artifIcial (and temporary) stabilization of the dunes and beaches, and discuss the impact of storms in promoting either the destruction or the preservation of these natural features in the future.
Most field trips at this meeting will examine outcrops visited by geologists for over 100 years; the road cuts remain the same-- but the interpretation changes. For our trip, the interpretation has remained the same, but the "outcrops" continuously change (in shape, form or position). As this is written the authors realize that the effects of a nor'easter or hurricane before October could signifIcantly change the form or location of our "outcrops". Most of our stops were within the "zone of breaking waves" within the past few years but all of them have been recently "restored" by beach nourishment. Coastal inhabitants-- particularly park managers and home owners on or near beaches demand a permanent position for their beaches, and have in place a powerful political lobby (at all levels of government) that will fight "beach erosion" and promote coastal maintenance and stabilization (which we realize only promotes more beach erosion).
But nature still remains a powerful influence for coastal change. The most obvious one is the coastal storm that erodes barrier island beaches, breaches dunes, overwashes barrier terraces and marshes, creates inlets, and floods mainland beaches. It floods or destroys all the "permanent" anthropogenic infrastructure, but only temporarily disturbs the habitats of the natural flora and fauna. As with a forest fire, after the initial devastation, the habitats are frequently extended and improved as the cycle of biological and physical evolution is renewed.
The less obvious change is the influence of the rate of sea level rise. It is now 0.6 m./1OO years and is estimated to be increasing to 1.5 m./100 years because of the global warming. Yet coastal management policies still reflect the "status quo"--the demands of the coastal managers and the communities. Because of the intense coastal development, they remain oblivious to the benefits of the storms, (which provide the natural sand migration) and because we haven't had a major hurricane crossing over this region in more than fifty years. There is never a discussion for the initiation of a policy that would emphasize the relocation or abandonment of destroyed structures after a major storm--only renourishment and renewed stabilization of the beach, and the return of larger (and more expensive) structures. In the meantime, the storms and sea level rise will continue. Thus, the dilemma!

A3: A Survey of the Natural and Urbanized Shorelines on Long Island, New York - A Dilemma in Coastal Management

New York skyline in view for camera shot.

Park near Captree Cove Restaurant
Park near Captree Cove Restaurant for last-minute
preparations and a pit stop

Robert Moses Causeway Bridge
Robert Moses Causeway Bridge that crosses Fire Island Inlet (see map) - one of the few parallel inlets on the East coast. Note Fire Island Lighthouse in distance on left; enter Fire Island.

STOP 1A. North side of Robert Moses State Park
The use of hard stabilization for erosion protection on the bayside of Fire Island.
Here we will examine the concrete "rubble" and and a gabion ramp that is being used as revetment to curtail bayside erosion at the end of the Loop Parkway. The reason for the initial loss of 75 meters of this beach and marsh relates to the curved spit seen at the western end of Fire Island (Democrat Point) in the distance. This was a coast-perpendicular inlet in the 1860's, but the extensive westward growth of the island from the lighthouse (over 6 Km.) has now produced a coast-parallel inlet (Figure 2). By the 1940's, it was in deep-enough water off Oak Beach to enable the flood-tidal currents and wave refraction to form a series of recurved spits at Democrat Pt. that began to constrict the inlet (Wolff, 1975a,b).
As the tidal channel narrowed and deepened, its velocity increased, and it began forming a curved "meander" shape as it impinged on the Jones Beach barrier at Oak Beach. The resulting erosion required the construction of a jetty at Democrat point (to trap the littoral drift) and the dredging and by-passing of the accumulated sand across the inlet. But during the early 1950's, sand was already passing around the jetty, and by 1959 it was again constricting the inlet (Figure 2.) causing erosion near Oak Beach.
This led to the construction of a reveted sand dike by the U.S. Army Corps of Engineers west of Oak Beach. But this produced deposition and shoaling behind the dike (near Oak Beach) - which again increased the extent of the "meander" curve of the tidal channel. Acting as a "point-bar" in a meandering river, the shoals diverted the tidal currents against the bayside of Fire Island, resulting in the loss of the beach. The rubble and gabion ramp were added in 1986 to curtail the erosion.
The effect of hurricane track near this area would have particularly disastrous regional consequences since there could be a breach anywhere along Oak Beach, as there was in 1901 and 1923 (Wolff, 1975b). Depending on the extent of spit development in front of the Federal jetty, (Figure 2) this could lead to the closure of the present inlet and a deepening and widening of the new one. Such an opening recently occurred at Westhampton Beach, but was soon closed by offshore dredging (Wolff,1994).

STOP 1B. Water tower at Robert Moses St. Park.
Use of soft stabilization for erosion protection on the oceanside of Fire Island.
This elongate mound is composed of gravelly sand trucked-in from the mainland under emergency conditions by the N.Y.S. Department of Transportation during the winter of 1990-'91 and again in 1992-'93 when an additional 20,000 cubic yards of sand were added. It is meant to augment the eroded dunes that once protected this traffic circle along the Loop Parkway. The history of beach erosion here dates from the 1940's, but dune erosion did not occur until the 1960's. Wave surge reached the oceanside parking lots east of here by 1973, and this zone of erosion has continued to migrate westward. Using slat fencing with periodic beach scraping, the dunes in front of the parking areas were restored in the 1980's, but erosion here, at this circle continues, necessitating the mainland trucking of gravel against the roadway.
A hurricane path near this area would not breach the barrier island, but it could create extensive damage to the parkway road, and to the water tower. The bridge is unlikely to be affected.

Views to Oak Island (right) and Oak Beach
(mouth of Fire Island Inlet) on left.

Note region of high dunes on left.

STOP 2. Gilgo Beach (Town of Babylon)
Use of soft stabilization for erosion protection of Ocean Parkway.
This stop was used by Wolff (1975b) to indicate the process of "ravinement" as described by Swift (1968) in which the active surf zone on a beach, during major storms, will expose old bayside marsh and lagoonal sediments. Such deposits were exposed on this beach during the nor'easters of 1972-73. Here is an area where over 400 meters of beach were eroded in 75 years--it was also used to demonstrate the effects of the process of barrier island "rollover" or landward migration. Once back-bay marsh sediments are buried beneath sands deposited as sand spits (by longshore currents) or overwash (from storm surges) they will later be overlain by sand from the terraces and dunes. As sea level rises, they will ultimately appear beneath the beach--were they can be re-exposed and excavated by the ocean waves (Figure 3). This beach has been renourished periodically since then (Buttner, 1989).
The wide beach at present is a result of several renourishment projects, initiated in 1988, that continue at present. Gilgo is the "feeder beach" for the cubic meters (or yards) of sand dredged and then pumped here from Fire Island Inlet. This sand will naturally feed the western town beaches and Jones Beach through the influence of the littoral drift.
The replenishment volume is as follows (Hanse, 1996):
1988 - 1 million cubic yards spread across 10,000 feet of beach
1990 - 1 million cubic yards spread across the same area
1992 - 1.7 mill. cubic yards spread across 18,000 feet of beach
1994 - 1.9 mill. cubic yards spread across 18,000 feet of beach
1994-'96 - an emergency stockpile of20,000 cubic yards.
Note also the elongate ridge of gravelly sand used to replace the dunes along the edge of the Ocean Parkway. During the 1950's N.Y. State had constructed a pavilion near this location. It was being undermined and eroded by the 1970's and was abandoned and dismantled by 1975. The foundation was broken into "rip-rap" to armor the beach, and acted as a 'stubby' groin that trapped sand east of this location. But this resulted in a loss of beach at this location that, by 1986 was extensive enough to erode the dunes and nearly reach the Ocean Parkway. As at Stop 1B. N.Y.S.D.O.T., using emergency funds, was able to truck-in the gravelly sand from the mainland to save this vital roadway. The roadway is built on sand-clay fill dredged from the bay during its construction in the late 1920's and will erode even more quickly if it is ever undermined by the ocean waves. The replenishment of sand at Gilgo Beach (Stop 1B.) has kept the waves from returning.
The effect of a hurricane path passing near this area could also be quite profound since it was already near the site of a former inlet. While tidal marshes are extensive, the adjacent dredged channel for the boat moorings and the intra-coastal waterway leave this portion of the island quite narrow and susceptible to inlet breaching (Figure 3). There is not enough sand left for overwash. In fact, one of the ironies is that the sand that has been pushed by wind or water onto the Ocean Parkway over the past 30 years is rapidly collected and returned to the beach. Undermining of the south side of the roadway is imminent--but only if the trucking-in of sand and gravel is eliminated.

STOP 3A. Tobay Beach (Town of Oyster Bay)
Use of soft stabilization for erosion protection of Tobay Beach and the beach pavilion.
Note the location of the Tobay Beach Pavilion and the line of the eroded natural dunes. Note also the size and "storm-proof' construction of pavilion #4. This site for a pavilion goes back to the 1940's - when the dunes were in front of this location and the beach extended seaward another 115 meters. The construction of the Federal jetty at Democrat Pt. on Fire Island (Stop 1A.) blocked the sand from crossing the inlet, causing erosion along all the beaches of the Jones Beach barrier island during the 1950's. Without inlet bypassing, this pattern will persist. Once the beach and dunes were eroded, various storms undermined and partially destroyed the older pavilion. It was rebuilt, refurbished (and re-destroyed) several times before being completely torn down in 1986. Yet, instead of being rebuilt on the north side of Ocean Parkway, it was rebuilt (because of a need for convenient public access) at the same site in 1987. It has been "embraced" by waves from various storms, but the deep, sturdy concrete pilings assure its preservation - as long as periodic beach nourishment remains available. This one, and all the pavilions and bath houses to the west (ie. at Jones Beach State Park) now occupy sites in front of the natural dune line. Even the huge ocean-side parking lots are now in front of the dunes. This again demonstrates the subtle but continuous pattern of natural sand migration that, without continual stabilization, will ultimately cause all the barrier environments to migrate landward (Figure 4).

STOP 3B. Tobay Beach - Wildlife Sanctuary
Return of pre-historic inlets into ecologically productive barrier island forests, ponds, and marshes.
This is the site of a pre-historic inlet that retained a large volume of sand and relatively wide dunes and marshes for a long period of time. The result is (on a small scale) the development of freshwater ecosystem in a mature forest - something more characteristic of the mainland. While relatively rare, they demonstrate that certain areas on barrier islands do not rapidly undergo landward migration if enough overwash sand was deposited during prior storms; such areas may remain stable for long periods, and unaffected by the rising sea (Buttner, 1987).
The effect of a hurricane across this region, as before, has more regional than local consequences. Because of the prior overwash and inlet-filling sand, the extensive terraces and secondary dunes, and the wide expanse of salt marsh, a breach through here remains unlikely.

Note the location of the dunes
Note the location of the dunes versus the location of the parking lot and pavilion.

STOP 4. Hempstead Beach Town Park
Use of hard stabilization for erosion protection at Jones Inlet.
Note the distance (over 350 meters) between the major roadway and the dunes. Though an urban park, there is a large "buffer zone" between the community and the beach - all urban development on barrier islands should have a management plan that will lead to this zonation. Once on the beach, view the shoreline from the last groin. Observe the wide beach and extensive dune field on the east (Jones Inlet) side of the groin. Note the large beach "re-entrant" and lack of dunes on the west side. This area was under water at various times during the 1970's and '80's, threatening the Town Pavilion (seen in the distance). Only the periodic sand bypassing from the inlet has prevented its annihilation. The last nourishment program ended in the spring of '96. You can already see the development of a beach scarp and the lowered profile as the swash undercutting continues to undermine the beach. Dune rebuilding through the use of slat fencing and Ammophila (beach grass) has been quite successful here, but only for a limited period.
This beach, near Jones Inlet, has a history similar to that of Oak Beach at Fire Island Inlet (Stop 1A.) The westward littoral drift from Jones Beach, as it moved into the deeper water in the inlet, created a series of recurved spits. By the 1950's the narrowing of the inlet forced the channel against the beach near the community of Pt. Lookout at the eastern end of Long Beach. Erosion also prevailed along much of Jones Beach. A jetty was now constructed at the western tip of Jones Beach. This led to the restoration of the state park beaches behind the jetty, but it increased the erosion at Pt. Lookout. This later required the construction of three groins east of this park, which trapped the sand supplied by the tidal currents in the inlet. But this also increased the rate of erosion beyond the most westerly groin - resulting in the need for periodic inlet sand bypassing for beach renourishment.
A description of the regional effects of wave surge from a hurricane passing near this inlet towards Freeport (Figure 5) was detailed by Coch and Wolff (l990). This was based on their observations of inland flooding and destruction of mainland communities behind tidal marshes after Hurricane Hugo in 1989. Less serious mainland inundation was noted along Long Island, opposite the recent opening of Little Pike's Inlet (Wolff, 1994). The extent of the enlarged tidal prism that must enter and exit an inlet during a hurricane are profound! The areal extent of the flood surge for hurricanes of different intensity has been depicted on N.Y. State SLOSH maps, and these depict inundations over hundreds of square kilometers that would affect thousands of houses.
Many beachfront homeowners have some low-level protection from bulkheads and retaining walls. But the ebb surge that follows will have some unexpected consequences. Besides opening barrier breaches into new inlets, it will also scour and erode the areas behind the bulkheads. These structures trap the ebb flood, preventing its return to the ocean. This "wall of water" will cause the houses or bulkheads to be overtopped or undermined as the surge seeks its way back to the ocean (Coch and Wolff, 1990).

STOP 5. Lido Beach Town Park
Use of soft stabilization for erosion protection.
The western edge of this park occurs at the boundary between an area with proper urban coastal management and an area that sees the return of community development directly behind the dunes. This region has also experienced periods of extensive dune breaching and beach erosion, but the periodic beach nourishment and the extensive care given toward dune development have made it a "healthy" beach. This is the last area within the next 50 Km. where one can see dunes in front of coastal structures. In fact, if we continued across the Hudson River into Staten Island, and then across the Arthur Kill into New Jersey, other than a few short stretches along Sandy Hook, we would travel past the 50 Km. of seawalls in N.J. and all the way to Pt. Pleasant before again encountering dunes of this magnitude in front of houses. What was a coastal dilemma becomes a coastal crisis!
In descending the dune boardwalk "overpass," note the location of the dunes with regard to the gold-painted twin spires of the Lido Beach Towers in the distance - their position aligns itself with the mid section of this building. Dune restoration has been frequently attempted across this section of the "New York Bight" from Long Beach to Sea Girt, but it will always fail because the position of the natural dune line is now well within the first block of houses on the urban streets. Without beach nourishment, all the "beachfront" houses would have been removed by erosion during the 1950's, and development has since increased 3-fold. The rebuilding of the dunes west of this area is an "effort in futility". As described at stops 2 and 3, the original dunes were trapped between the rising sea and the most shoreward anthropogenic structures--boardwalk, roadways, or houses (Figure 6). Other than this local area, any new dune restoration will rapidly be eroded. Not until the relocation or abandonment of the first 1-4 rows of houses can the shoreline adapt an equilibrium position that would retain natural dunes for storm protection.
The effect of a hurricane path anywhere in the New York Bight, with its large coastal population density, would be overwhelming Wolff,( 1992) and Coch,( 1995). Though the erosion problems persist, the area cannot be abandoned, and at any expense, beach nourishment (without dunes) must continue--therefore, the coastal dilemma!

STOP 6- Edgemere Section of Rockaway Beach
Beach dynamics and inlet sedimentation along a highly urbanized shoreline, Rockaway Peninsula, Queens County, New York.
Historical records show that the Rockaway Peninsula was largely pristine until the 1850's. In 1835, large areas were covered by cedar trees and sand ridges rising in places to altitudes of 25-30 feet above sea level. Urbanization, starting in the 1850's, was largely in the form of summer home developments. With the coming of the railroad in 1893, permanent communities became established. The increasing urbanization was to result in drastic changes in the morphology and hydrography of this area.
The Rockaway Peninsula, and the Coney Island barrier island to the east (Figure 7) are the most heavily urbanized and eroded hurricane - prone shorelines in the United States (Coch, 1995). The original dunes covering the Peninsula are long gone and the beaches have receded to such a degree that there is no longer any natural storm surge protection for the high-density structures along this shoreline. The major cause for this continual erosion has been the removal of sand from the longshore drift system by engineering structures and stabilized inlets in the areas to the east. This has deprived the beaches of Western Long Island of a sand supply sufficient to replace that lost to storms. In order to maintain this recreational area and protect the structures, the Army Corps of Engineers must replenish this stretch every 3-5 years.
Our stop will cover the shoreline area from Beach 37th to Beach 25th Streets. We hope to answer the following questions:: 1) how does beach morphology and sediment dynamics differ from that along more pristine shorelines?; 2) how has this shoreline evolved and what does this imply for the future?; 3) What accounts for the exceptional rate of erosion along this coastal segment? and; 4) how have engineering structures affected sediment dynamics in the vicinity of East Rockaway Inlet.
The area we will be examining today has a history of severe erosion. It was replenished in 1995, when it was built out 140 feet from the boardwalk. By March of 1996 it had eroded back nearly to the boardwalk. Replenishment in June 1996 built the beach out 240 feet from the boardwalk. High waves associated with the passage of Hurricane Bertha in mid-July, 1996, has already caused a beach recession of 40 feet.
The Eastern Rockaway Peninsula has been the subject of a continuing investigation by Queens College students since March of 1996. Examination of the beach section in March of 1966 showed a most unusual stratigraphic section. Sedimentary structures included upper flow regime plane beds, well defined channels oriented in a number of directions and avalanche bedding. The sediments consisted of sand, gravel and whole shells as well as shell fragments. However, as much as 5-30% of the section consisted of solid waste dating from the 19th Century. The debris included numerous rounded bricks, pieces of drainage pipe, pottery, plates bottles, personal items, animal bones and a few pieces of silverware and coins (Liogys et al., 1996).
We considered two working hypotheses to explain this deposit. The dredging could have uncovered an old borrow pit into which solid waste was dumped in the 19th Century. Another possibility is that the debris was washed offshore in the ebb surge of a past hurricane.
Historical records synthesized by Fuqua (1996) indicate that a barrier island (Hog Island) existed 1,000 feet offshore of the Rockaway Peninsula in 1879. A number of recreational facilities existed on Hog Island at that time and they were reached by ferry and causeway from the Rockaway Peninsula. The New York Times of August 21, 1893 reported that a major storm completely inundated Hog Island and it was "the beginning of the end for the island". Later newspaper reports indicate that Hog Island disappeared completely in nor'easter storms in 1893-4. The major storm was probably the "Jamaica Bay Hurricane" of 1893. The eye of that Category 3 storm probably did not pass over Jamaica Bay but crossed the coast in what is now the western part of Nassau County (B. Jarvinen, 1996, personal communication). This would have put the Rockaway area on the weaker, or left side, of that hurricane, so how can we explain the extraordinary coastal damage that was reported? The wave and surge levels reported were much higher than expected, because of the unique shoreline orientation and offshore bathymetry that occur in this region (Coch. 1994). The obliteration of structures on Hog Island would have provided debris that was washed onto the adjacent sea floor and covered by sand in the following decades. Dredging operations by the Army Corps of Engineers in 1995 (just south of the inferred position of Hog Island) returned this material to the land as part of the hydraulic fill used for beach replenishment. As you look around at the high rise buildings right on the boardwalk, think about the consequences of a major hurricane making landfall again in this highly urbanized area in the future.
Beach sedimentation in this area today consists of swash buildup of the beach face between storms as well as deflation of surface sands by southerly winds. The sand accumulates as drifts against the boardwalk. Some of the sand is blown under the boardwalk to form drifts against eroded vegetated dune remnants with incipient soil profiles. We will examine some of these dune remnants and discuss the inevitable consequence of "barrier rollover" in this area.
There are two sets of groins in the area (Figure 8). The older wooden groins were poorly maintained and are now largely destroyed. The newer stone groins function as effective sediment traps. The most easterly stone groin is at Beach 35th Street at our field trip stop.
A number of factors are responsible for the severe erosion in this area. Observations over several years suggest the following scenario for the water and sediment dynamics in the East Rockaway Inlet area. These dynamics are shown in generalized fashion in Figure 3. Sand moves in the predominant east to west drift toward the jetty at Atlantic Beach. Most of this sand is trapped against the jetty, but a portion is swept across the inlet area toward the Rockaways. Bathymetric contours (Figure 8) indicate shoals that suggest the presence of an ebb tidal delta on the north side of East Rockaway Inlet. Some of the sand moved across East Rockaway Inlet is transported by waves refracted around that ebb tidal delta, and moved towards the inlet. The last stone groin at Beach 35th Street traps some of that sand, but most moves past the area towards the inlet. This sand is deposited in the vicinity of the "light" (Figure 8) where the ebb currents block further penetration into the inlet. This scenario accounts for the presence of a sand-starved section from Beach 35th to Beach 25th Streets and the severe erosion that occurs continually along that coastal segment.

A4: STRATIGRAPHY AND HYDROGEOLOGY OF THE UPPER CRETACEOUS RARITAN, MAGOTHY, AND CHEESEQUAKE FORMATIONS, N.J. COASTAL PLAIN
PETER J. SUGARMAN
New Jersey Geological Survey
CN-427
Trenton, New Jersey 08625
This field trip (Figure 1) examines some of the remaining pits exposing Cretaceous rocks in Middlesex County. Continuing rapid development of Middlesex County has led to the closure of many of the best geological exposures of the Cretaceous Raritan and Magothy Formations. Fortunately, many of these exposures have been documented and described in previous field guides including Owens and Sohl (1969), Owens et al. (1977), and Olsson (1987), and in geologic maps (Owens et al., 1995; Sugarman et al., 1995).
The stratigraphy of Cretaceous rocks in Middlesex County, New Jersey has been studied for well over a century. Early economic studies concentrated on the use of clay deposits for making earthen and stoneware pottery, and fire brick (e.g., Ries et al., 1904). Because small beds or lenses of clay were economically important, a stratigraphic terminology developed which often had local significance, but lacked criteria for regional correlation.
Later studies focused on the growing importance of these deposits as sources of ground-water (e.g., Barksdale et al., 1943). Ground-water supply and contamination studies continue to be the major focus of recent geologic and geohydrologic studies in the northern New Jersey Coastal Plain, in large part due to increasing ground-water withdrawals, declining water levels, and saltwater intrusion.
This trip will examine outcropping geology of the Cretaceous Raritan and Magothy Formations (Figure 2) to: 1) develop familiarity with the prominent members (or facies) within these formations; and 2) place these facies into a hydrostratigraphic framework. We will also examine the newly named Cheesequake Formation (Litwin et al., 1993).

A4: STRATIGRAPHY AND HYDROGEOLOGY OF THE UPPER CRETACEOUS RARITAN, MAGOTHY, AND CHEESEQUAKE FORMATIONS, N.J. COASTAL PLAIN

STOP 1: Raritan Center, Edison
Owner: Federal Business Centers.
In the drainage ditch on the Federal Business Centers, ∼30 feet of the Raritan Formation are exposed. This formation is capped (at ∼100 feet) by 5 feet of surficial material consisting of cross bedded sand and gravel. At this stop, the Raritan Formation consists of (from top down):
10 feet of interbedded black laminated to thin bedded clay.
10-15 feet of pale yellowish orange to grayish orange cross-bedded fine to coarse sand, occasionally micaceous.
10 feet massive black clay-silt; very lignitic, with pyrite, occasional 2 inch diameter siderite concretions, and interbedded fine sand.
1 foot of white, very clayey sand with possible burrows or roots. Contact of this white clayey sand and black clay above is irregular.
No marine fossils have been collected at this site. Pollen collected from black clays has been assigned to Pollen Zone IV of Sirkin (1974). This zone is equivalent with the Complexiopollis-Atlantopollis Assemblage Zone of Christopher (1979) which is predominantly middle to upper (?) Cenomanian.
Prior to recent industrial development, the Farrington Sand Member of the Raritan Formation was exposed across the road at lower elevations.
5-10 feet of an interbedded crossbedded, medium micaceous sand and dark gray, very woody claysilt, which can be both massive and bedded. Interpreted as meandering stream deposit. Also assigned to Pollen Zone IV. At the base of the pit (∼20-30 feet elevation), the Farrington was in contact with a red shale and clay.

STOP 2: Abandoned Pit of the Sayre & Fisher Brick Co.
Owner: K-Land Corporation #5
The Sayre & Fischer brick pit offers the best exposure of the Woodbridge Clay Member in New Jersey. It also contains the contact of the Raritan and Magothy Formations in the southeastern part of the pit. This stop has been previously described by Owens and Sohl (1969), Owens et al. (1977) and Olsson (1987, 1980). The Woodbridge Clay at the pit contains:
30-40 feet of black laminated silts and clays containing many layers of siderite- and iron-oxide- cemented sand. Laminations destroyed by burrowing in the top section. Fossil imprints occur near the middle and top of the Woodbridge Clay in micaceous siderite sandstone concretions (Owens et al., 1977). Pyrite and lignite are scattered throughout the Woodbridge.
5-6 feet of sand and clay containing wood (often in an upright position) were previously exposed at the base of the pit and are now below the upper level of the pond. Richards (1943) and Stephenson (1954) describe a diverse assemblage of bivalves and gastropods. Stephenson (1954) correlates this fossiliferous layer with the Cenomanian Woodbine Formation of Texas. Sohl (in Owens et al., 1977) interprets this fossil bed to be the result of a winnowed storm deposit, placing an infaunal-dominated molluscan assemblage into a marginal marine environment Recently, the upper Cenomanian ammonites Metoicoceras bergquisti and Metengonoceras sp. were collected from the Woodbridge Clay at this pit (Cobban and Kennedy, 1990). The Woodbridge Clay is also the type for the Cenomanian Complexipollis-Atlantopollis assemblage Zone (Christopher, 1979).

STOP 3: Sayreville Recreational Complex.
Owner: The Borough of Sayreville
The closing of the South River Sand and Gravel Pit (see Owens et al. 1977 for a description) several years ago eliminated the finest exposure of the Old Bridge Sand in New Jersey. This exposure of the Old Bridge Sand member of the Magothy Formation is a good (but slumped) outcrop showing a major sand channel in the Old Bridge Sand. To the east of this exposure is a graded, seeded bank which offers a partial view of the very carbonaceous, laminated clay-silt and fine sand which was better exposed at the South River Sand and Gravel Pit, and is a common facies of the Old Bridge. The Old Bridge Sand (and thin surficial cap) at this site consist of:
0-5 feet of light brown surficial sand and gravel. At the contact of the surficial unit and the Old Bridge Sand (∼90 feet elevation) is an ironstone layer.
25 feet of medium (occasionally coarse) micaceous cross bedded sand. Cross-beds consist of small 2-3 inch troughs, sometimes with thin clay stringers, and occasional thin lignitic cross-lamina

STOP 4: John F. Kennedy Park - Lunch
The park is the site of an old pit where there used to an excellent exposure of the South Amboy Fire Clay Member of the Magothy Formation. This member was described at this location by Owens et al. (1977; p. 96) as:
" ... a tough, White, light -blue to gray or red-mottled clay. Locally it may be quite dark and contain some lignite ... ". "Sulfur-balls" (round, ball-like aggregates of pyrite, 1 to 4 inches in diameter) are found in many places, and disseminated pyrite is common throughout the unit. At some localities, small pieces of amber occur near the base of the South Amboy".
On the other side of Washington Avenue we passed the DuPont plant on the way to Kennedy Park. A split spoon well from the site, described below, gives thickness and description of strata outcropping at the park, as well as in the shallow subsurface.
DuPont Parlin FW-5 (Ground Elevation 107 ft; depths reported below land surface).
Pennsauken Formation (∼40 feet thick)
5-7': Yellowish red poorly sorted fine -very coarse sand, some rock fragments, trace granules and clear mica, 1 % opaques.
10-12': Reddish yellow (7.5 YR 6/6) gravel (maximum 3/4"), gravely sand, some silt, poorly sorted, with rock fragments and feldspar, 2% opaques.
15-17': Light brown (7.5 YR 6/4) gravel (maximum 1.25"), gravely sand, and some rock fragments, with more large gravel.
20-22' Light gray (10YR 712) sand, well sorted, mixed with sandy gravel.
25-27': Very pale brown (10YR 7/3) moderately sorted sand, mostly fine with some medium, trace mica.
30-32': Light reddish brown (5YR 6/3) sand, poorly sorted, mostly medium, trace of clear and green mica
35-37': Reddish yellow (5YR 6/6) clayey gravely sand; gravel to 1" maximum.
Magothy Formation - Old Bridge Sand (∼55 feet thick)==========
40-42': Light gray (10YR 7/2) sand, well sorted, fine, clear quartz, trace medium, some fine opaques.
45-47': Same as above.
50-52': Light gray sand, medium.
60-62': Light gray sand, medium, some fine and coarse, minor mica and carbonaceous material ..
65-67': As above, medium to coarse, trace gravel to 1/4".
70-72': Light gray to light brownish gray coarse to very coarse sand, trace mica
75-77': Sand, clayey, medium to -very coarse, with some 1/2" gravel, becoming light yellowish brown.
80-82': Sand, light gray, coarse, with occasional gravel.
85-87': Yellowish gray (5Y 7/2) to light brown (5YR 5/6) interbedded clay and fine to medium sand.
90-92': Light gray sand, medium to coarse, poorly sorted, with some mica
Magothy Formation - South Amboy Fire Clay (∼32 feet thick)=========
95-97': White (N9) - pinkish gray (5YR 8/1) sand, very fine to fine, trace silt.
100-102': Yellow gray to light brown sand, very fine to fine, laminated, trace silt.
105-107': Yellowish gray (5Y 7/2) silty fine sand, with mica.
110-112': Sand, silty, fine to medium, with some coarse to very coarse.
115-117': As above, various shades of orange (10YR 8/2, 8/6, 7/4).
120-122': Light gray (N7) silty sand, very fine, well sorted, 1 % clear mica, trace lignite.
125-127': Medium dark gray laminated clay-silt, 5% fine sand, 1% pyrite, mica, trace lignite.
Raritan Formation - Woodbridge Clay (∼100 feet thick)==============
130-132': Light to medium light gray clay-silt, some very fine to fine sand, with some elongated lignite pieces.
135-137': Medium-dark (N6-N3) gray, as above, with more clay, carbonaceous material, and mica
140-142': Light gray (N7) silt, 1-2% very fine sand, 2% mica (White).
145-147': Light olive gray (5Y 611) very fine to fine sand, some silt, white mica, and trace of fine carbonaceous matter.
150-152': Light olive gray (5Y 611) laminated silt, with abundant finely disseminated mica and carbonaceous material, some siderite.
160-162': Grayish orange (10YR 7/4) sand, very fine -fine, with white mica and some carbonaceous material.
165-167': Light gray silty fine sand, mica and trace wood.
170-172': Dusky yellowish brown (10YR 212) clay with some very fine sand laminae, trace mica, with occasional thin siderite lenses.
175-177': Moderate brown weathered siderite stained clay-silt
180-182': Dark to moderate yellowish brown (10YR 4/2 to 5/4) laminated clay/silt with very fine sand, 2-3% finely disseminated mica and carbonaceous material.
185-187': Light gray (N7) clayey silt, laminated (?), with finely disseminated mica and carbonaceous material.
195-197': Light gray silt, as above, less mica
205-207': Light olive gray to olive gray (5Y 611-411) clay, some silt, trace mica; massive.
215-217': Medium dark gray (N4) carbonaceous clay, slightly micaceous.
220-222': Medium dark gray (N4) silty clay with some very fine to fine sand, 2% clear mica. 1 % fine carbonaceous material.
Raritan Formation - Farrington Sand (minimum 13 feet thick)=========
227-240': Light gray sand, medium to very coarse, tr.lignite.

STOP 5: Gully by Cheesequake Creek and Garden State Parkway
Owner: Kaplan Companies
The gully contains a complicated arrangement of facies generalized by Olsson (1987) as:
0-29 feet of "...dark gray sands and carbonaceous-rich clays, uniformly cross-bedded sands, intermixed flaser bedding, and layers of rip-up clasts." Sands are very micaceous.
16 feet of "...dark gray laminated clay, dark gray alternating sands and clays, and carbonaceous-rich layers".

STOP 6 Route 34 - Northwest tributary to Lake Leffert
Owner: Russ Weber
When initially entering the creek, the Merchantville and Woodbury Formations are exposed. They are gradational units, with no clear contact between them. Exposed in the northern part of the creek is:
0-5 feet of surficial gravel.
5 feet of massive to laminated slightly glauconitic clay-silt (Woodbury Formation).
2-3 feet of massive, burrowed clayey glauconite sand (Merchantville Formation).
Further down the creek, the contact of the Merchantville and Cheesequake Formations are exposed. The contact is irregular and burrowed with a 3 to 4 foot reworked zone, and siderite concretions along contact. Along the contact is a burrowed brown clay with dark green medium-to-course glauconite sand of the Merchantville Formation in the burrows.
The Cheesequake Formation is exposed in the southern part of the creek (tributary to Lake Leffert). Its total thickness is -30 - 35 feet; descriptions are developed from composite sections. We will see the upper beds of the Cheesequake at this locality.
4 feet of pale to moderate to dark brown fine sand (lighter colors reflects more weathered sands), laminated with yellowish brown clay-silt, finely burrowed, with much fine dispersed mica (mostly clear) and lignite.
6 feet of massive olive-gray clay-silt with very fine sand, very micaceous and lignitic.
The lower beds down the creek and in gullies just to the north off Morristown Road are more fine grained and glauconitic:
10 feet of massive, dark greenish-gray clay-silt with very fine to fine sand, very lignitic and micaceous (clear, white, green, and brown - very fine to very coarse plates), and glauconitic (4-5%, mostly coarse and immature). Some delicate sand filled burrows are present.
1 foot of olive gray clay-silt, glauconitic (20%, fine to medium, botryoidal and accordion forms), with some very fine sand, very micaceous (mostly clear), and slightly lignitic. Contains 0.25-1 foot in diameter pale to grayish brown siderite concretions. At the base of the unit are clay filled burrows (0.5" diameter), occasional molds of gastropods, and siderite concretions (at basal contact with the Cliffwood Beds).

A5: DEGLACIATION OF CENTRAL LONG ISLAND
LES SIRKIN
Earth Science
The moraines of Long Island were deposited during the late Wisconsinan Stage of the Pleistocene Epoch by the lobate margin of the Laurentide Glacier. This glacier advanced into the Long Island region twenty-two thousand years ago (22ka) and deposited the terminal moraine and the outwash plain to the south. Between 22ka and 20ka, the ice receded northward across Long Island, establishing at least two recessional positions. During each stand of the ice, recessional moraines were deposited, proglacial lakes developed between the ice and the moraines, and meltwater carved drainage channels southward across the outwash plain and laterally along the ice front. In central Long Island, these features, which can be identified by tracing the recession of the Connecticut Lobe of the glacier northward from the Ronkonkoma Moraine, the terminal moraine of this lobe, include the Connetquot-Nissequogue meltwater channel that drained north to south through outwash plains and proglacial lake basins, the Stony Brook Recessional Moraine, and finally the last recessional moraine, the Roanoke Point Recessional Moraine, along what is now the northeastern coast of Long Island, and draining of the proglacial lakes in the Long Island Sound basin. The glacial history of the region is the subject of Dr. Sirkin's books "Eastern Long Island Geology" and "Western Long Island Geology.
In the context of geologic time-- over four and one half billion years-- the formation of Long Island is barely a footnote. It took only about two thousand years, between twenty-two thousand and twenty thousand years ago for glacial advance and deposition of the terminal moraine and deglaciation and deposition of the recessional moraines. From twelve thousand years ago to the present, sea level rise and coastal erosion have shaped the moraines and created the characteristic, fish-shaped Island geography. Consequently, the variety of glacial and postglacial features, ranging from ice-contact deposits to relict landforms is readily available for study. This geology is well represented and readily accessible in coastal bluffs and on the surface, and is easily seen from roadways, beaches and trails.

A5: DEGLACIATION OF CENTRAL LONG ISLAND

STOP 1. Heckscher State Park
The trip starts at the entrance to Heckscher State Park (Bay Shore East Quadrangle). Follow the roadway loop through the park for four and one-quarter miles.

The late Wisconsinan outwash plain underlies the park
The late Wisconsinan outwash plain underlies the park, salt marshes and the bay to the south. A filled-in, crescent beach forms the south shore of the park. The Connetquot River estuary drains into Nicoll Bay over one mile to the northeast, but prior to Holocene submergence the river probably meandered to the southwest against the Heckscher shore. A few miles to the south, Fire Island forms the barrier beach that encloses Great South Bay.

Great River Road follows the west bank
Great River Road follows the west bank on the outside curve of the southernmost meander of the river, beginning south of Sunrise Highway. The west bank is the steep side (outside) of the meander loop, and it rises about fifteen feet above the river. The topography of the river valley is somewhat obscured by development.

Rt 27A essentially follows the meander curve
Rt 27A essentially follows the meander curve but well above the cut bank. Note: the field trip follows the meanders of the meltwater channel valley in the direction of glacial recession and against the direction of late-glacial meltwater discharge. North of the terminal moraine, the meltwater channel meandered and lengthened as the ice front receded and tributary channels drained proglacial lakes.

Cross the Connetquot River valley near Lower Pond.
The river has been dammed here to form Lower Pond and East Pond. The river bottom is partially hidden by development and highway ramps to the south. To the north, stands of trees and shrubs mask the ponds and the channel.

STOP 2a. Western margin of the Connetquot valley
Stop where convenient to become oriented to the terrain. Note that while the river meanders are easily followed on the topographic map, extensive housing development hides the valley. The road follows the western margin of the Connetquot valley, passing the Bayard Cutting Arboretum and the Connetquot State Preserve (Central Islip Quadrangle). The Connetquot River, while gently meandering on its flood plain, has been dammed for mill ponds and a fish hatchery. A well defined, west-trending valley meander forms the river's reach and a low eroded bank in the outwash between the Long Island Railroad tracks and the village of North Great River. But it is against the easterly bend of the valley, located in the State Preserve to the south, that meltwater carved a twenty foot escarpment. The breadth of the valley meanders compared with the width of the Connetquot channel shows the river to be decidedly underfit in this segment. Evidently, a much more robust, meltwater-laden river established the meander pattern and shaped this much broader valley (Figure 1b). The fifty-foot contour line and the adjacent contour lines outline the valley morphology from meander to meander northward from the State Preserve to the Ronkonkoma Moraine.

STOP 2b. "Headwaters of Connetquot River."
The valley can be entered from a gate east of the sign with permission from the State Park Preserve, as indicated.

Nichols Road crosses the outwash plain
Nichols Road crosses the outwash plain between the Ronkonkoma Moraine to the north and the rapidly narrowing river valley to the east.

STOP 3. Sand pit in the Ronkonkoma Moraine.
Walk to the west to the remnant exposure in the extensively mined and once two hundred foot high segment of the Ronkonkoma Moraine. Here about twenty feet of outwash is capped by a thin (two to four foot) layer of brown sandy and gravelly till. Erratics are scarce. The thin soil horizon (A?) at the top is formed on loess (Figure 4).

STOP 4. The headwaters are buried here
The headwaters of the Connetquot River drainage are now buried under the roadways. The watershed begins in a significant gap in the Ronkonkoma Moraine. Stop, if traffic allows, as near the gap as possible, even though roads and residential development obscure the view. The late-glacial meltwater channel was incised through the moraine as meltwater carved an easterly meander sixty feet above present sea level (Figure 1b). In a short excursion to the east, Vanderbilt Motor Parkway ascends the Ronkonkoma Moraine (Figure 3a and b). To the west, the Parkway crosses the gap and climbs the meander-scarred moraine--although not easily seen due to the highly suburbanized character of the terrain.

The road follows the meander scar
The road goes up a hill that follows the meander scar. The evidence of meander erosion shows that meltwater flowed at this higher elevation during the interval of valley widening. Upstream, the valley turns sharply from the northwest against the steep proximal slope of the moraine, incised by a seventy foot-high meander scar.
The northern half of this meltwater-formed meander has become, in the context of the modem drainage, the headwaters of the north-flowing Nissequogue River drainage, a region of wetlands and ponds within the fifty-foot contour line. The river valley casts two broad meanders over the relatively flat basin enclosed by the Ronkonkoma Moraine to the south and the recessional moraines of the last glaciation to the north--the Stony Brook Moraine to the northeast and the Northport Moraine to the northwest). These moraines may be recessional moraines of the Connecticut and Hudson lobes of the glacier, respectively, or segments of the moraine of a sublobe of the ice front that formed between the main lobes at this stage of glacial recession (Figure 3c and d). This lowland, characterized by meanders incised into a plain of low relief, wetlands and pitted outwash, is underlain by lake clays deposited on the floor of a proglacial lake formed between the terminal moraine and the ice front during deglaciation.

Terry Road enters hummocky topography
Terry Road enters hummocky, stream-dissected and kamic topography north of the Ronkonkoma Moraine.

Dissected kame or outwash fan
Note the exposure of a dissected kame or outwash fan on the east side of Terry Road.

Another possible dissected kame or outwash fan
Another possible dissected kame or outwash fan can be seen on the north side of the junction of Terry Road and Rt 25, Middle Country Road. Eroding sand and gravel forms the slopes.

STOP 5. Proglacial lake basin
Stop where convenient to consult the topographic map (Central Islip Quadrangle), get your bearings, and consider these features. Terry Road and this segment of Rt 25 follow the edge of a proglacial lake basin that formed between the Ronkonkoma Moraine and the receding ice front during the late Wisconsinan. The roads curve against the meander-cut valley wall. The underfit channel of the Northeast Branch of the Nissequogue River first wanders northward through (former) wetlands before making a broad northward curve.
The channel is divided into several small ponds formed from dammed-up stream segments. It then heads westward, south of Smithtown, to New Mill Pond, also the result of a dam, and then turns northward across the flat channel bottom and flood plain deposits where the valley narrows significantly. While clearly seen on the topographic map, the channel is obscured on the east side by housing, office buildings and a shopping center. The poor drainage on the proglacial lake-bottom clay beds, cf. the Smithtown Clay, of late Wisconsinan age, serves as a reminder of the geologic history of this lowland. Emerging from the lake basin southwest of Smithtown, the valley turns northeastward. The narrow river channel is incised into the outwash with high banks on either side. The river can be seen south of and parallel to Rt 25, west of the Rt 25-Rt 25A fork, west of Smithtown, where it flows northeastward through a young hardwood forest established on the flood plain. It then crosses Rt 25 just east of the Rt 25-Rt 25A fork, about one mile west of the Rt 111 intersection.
The narrow valley persists through a broad eastward meander north of Smithtown where the meltwater channel cut through the recessional moraine. The modern Nissequogue River actually meanders in a confined belt on its own marsh-covered flood plain, but through steep valley walls of the meltwater channel up to one hundred feet high. The river becomes tidal near Mill Creek, and tidal flats cover channel deposits northward to the river mouth. Where the Nissequogue River enters Smithtown Bay, it is restricted by sand bars from both the east and west sides. On the east side, a northwest-hooking spit, Short Beach, indicates the dominant direction of littoral drift. The spit has forced the river outlet to bend further westward; the west sand spit has, in turn, confined the westward discharge.
A proglacial lake basin extends to the northeast and underlies much of the Saint James region. This basin drained, in part, to the southwest via narrow channels into the Nissequogue meltwater channel in the Village of the Branch and Smithtown, and eroded the interfluves into narrow ridges. One such ridge was described by Fuller (1914) as an esker which bordered a drift-less area [i.e. the proglacial lake bed of the current model] and was somehow seen as evidence of the greater age of that terrain.

Road rises onto the Stony Brook Moraine.
The road rises onto the distal slope of the recessional moraine, the Stony Brook Moraine. The river lies near the interlobate angle, but Nissequogue River Road and adjoining roadways cut through successive, washboard ridges and swales of the Stony Brook Moraine for over three miles between here and the north shore. This segment of the Stony Brook Moraine is typically hummocky and has a number of kettles. The east-west washboard texture is probably the result of stillstands of the ice front during recession and postglacial channel deepening.

A good view of the river and moraine
A good view of the river to the west (left) and the eroding roadcut in the moraine on the east (right) side.

Views of Nissequogue tidal estuary to west.

The road descends the kame moraine
The road descends the kame moraine to the level of the salt marsh, and then enters Smithtown Short Beach.

STOP 6a. Consider the variety of coastal landforms.
Park and walk to the beach. Consider the variety of coastal landforms. To the southwest, a bluff has been cut into the moraine by coastal processes. To the northeast, you can see the topography of the Roanoke Point Recessional Moraine forming distant bluffs on the Old Field headland. The successive ridges of this eroded westernmost extension of the moraine are apparent from this perspective. Try to imagine the confluence of the Roanoke Point and Sands Point moraines to the north in what is now Smithtown Bay in late-glacial time before the deposits were erased by meltwater streams and later by coastal currents. To the east, large erratics in the Bay are a reminder of the continuing erosion of the moraine and recent increments of sea level rise. Today, bay currents are dominantly east to west along this beach.

Meanders of the meltwater channel valley
Here you can observe the estuary and the meanders of the meltwater channel valley south of the Short Beach spit. The Nissequogue River estuary, the drowned and silting mouth of the north-flowing river, is confined by two sand bars. Short Beach trends east to west and then northwest on the east side and forces the river to the northwest; the opposing Sunken Meadow Beach on the west side channels Sunken Meadow Creek eastward parallel to the bar and into the estuary.

Last prominent ridge of the Stony Brook Moraine.
Long Beach Road cuts northeasterly across the last prominent ridge of the Stony Brook Moraine.

The eroded edge of the moraine
The eroded edge of the moraine, at the base of Long Beach, reveals a 100' high bluff with an exposure of thin (2-4 ft), sandy melt-out till over outwash, capped by 5-10 ft high sand dunes (Figure 4).

STOP 6b. Long Beach. Stony Brook Harbor
Stop 6b. Long Beach. Stony Brook Harbor, the mouth of a north-trending stream valley cut into the Stony Brook Moraine, is diverted eastward through Porpoise Channel by. the one and one half mile long, Long Beach sand bar. This estuary is also silting in. On the east side of Smithtown Bay, Long Beach forms a narrow inlet along with West Meadow Beach, a spit that trends southward along the Setauket coast from the distal margin of the Roanoke Point Moraine at Old Field to the northeast. The Roanoke Point Moraine forms the headland in a series of washboard ridges. As mentioned, the geographic extension of the trends of the Roanoke Point Moraine from the east and the Sands Point Moraine from the west meets in an interlobate angle near the north-central margin of Smithtown Bay (Figure 3d-f).

A6: HIGHLIGHTS OF STATEN ISLAND GEOLOGY
Alan I. Benimoff and Anderson A. Ohan
Department of Applied Sciences
The College of Staten Island
Staten Island, NY 10314
Since the 1975 NYSGA field trip on Staten Island (see Ohan et al. 1975) there have been many contributions to the geology of Staten Island. Staten Island geology(see figures I and 2) is very diverse, consisting of Cambro-Ordovician serpentinite, Jurassic diabase, Newark Group sedimentary rocks, Cretaceous and Pleistocene sediments. In addition, there are numerous wetlands, stream drainage basins and the world's largest landfill. Staten Island has an interesting plate tectonic history as John McPhee notes in his 1993 book entitled Assembling California "Southeastern Staten Island is a piece of Europe glued to an ophiolite from the northwest Iapetus floor". The aim of this trip is to give highlights of the geology of Staten Island.

A6: Highlights of Staten Island Geology

Outcrops of Staten Island Serpentinite on right and left

STOP 1. The Staten Island Serpentinite
This outcrop represents the largest continuous exposure of the Central-Zone Serpentinite on Staten Island, and is a foliated serpentinized Harzburgite, composed essentially of Lizardite (48-71%), chrysotile (15-30%), and olivine (10-15%). Antigorite, anthophyllite, talc and magnetite are present in minor concentration (Puffer & Gennine 1994). Numerous veins are filled with carbonates, chrysotile or talc. A number of folds exist displaying a N40°E - N 45°E trend and a NE plunge. Several folds have western limbs that are overturned and are cut by high angle NE-SW trending faults. At this locality, the trend of one hundred and twenty-five fractures were measured and statistically plotted, in an attempt to determine the relationship between the joint patterns and the existing structure. The fractures can be categorized into 3 types based on their orientation to the folds. Type (1) longitudinal joints subparallel to the axial planes of folds, and may be release joints. Cross Joints This joint set is oriented normal to the fold axis and commonly develop in the hinge zone of folding by stretching parallel to the fold axis. Oblique Joints may be conjugate shear sets produced by a shortening normal to the axis of folding (Davis & Reynolds 1996).The fracture pattern relationship with the folds indicates a common origin. It is suggested that the folding, faulting and fracture patterns were produced by a SE-NW oriented compressional stress and may be related to the Mid Ordovician Taconic event.

STOP 2. The Graniteville Quarry.
At this locality, we see an extraordinary example of two coexisting magmatic liquids, now represented by the diabase of the Palisades Sill and a pyroxene Trondhjemite derived by fusion of the the margins of a xenolith of sodium rich Lockatong Argillite (Benimoff and Sclar, 1978, 1980, 1984, 1988, 1992, 1996; Sclar and Benimoff,1993). The diabase is composed dominantly of plagioclase (An61Ab38.8Or0.2) and augite (En34-44Fs17-31 Wo35-42). The trondhjemite is composed dominantly of quartz-albite granophyre in which are enclosed large discrete crystals of albite(Ab99An0.52Or0.44) and Ca-rich pyroxene. Minor constituents include interstitial calcite, titanite, ilmenite, optically homogeneous titanomagnetite, nickelian and cobaltian pyrrhotites, apatite, and sphalerite. The modal mineral percentages are clinopyroxene 38, albite 38, quartz 18, titanite 2.7, calcite 1.3, and opaques 2.0. The xenolith is now a hornfels and exhibits a granoblastic texture. The hornfels is composed dominantly of albite and quartz and subordinately of calcite, titanite, apatite, ilmenite, and actinolite. The modal mineral percentages are albite 66, quartz 30, titanite 2.3, calcite 0.9, apatite 0.5, and actinolite 0.3. Normative albite ranges from 56.4 to 80.2 wt.%, whereas normative quartz ranges from 7.0 to 35.4 wt.%. Chemical analyses(Table 1) reveal that diffusion of calcium, magnesium, iron, and sodium ions occurred across the liquid-liquid interface.
On the surface of the bedrock in the quarry area, numerous ice-sculpted features are present. These include shallow trough-like grooves, striae, and crescentic marks.

View Landfill

Arthur Kill Correctional Facility on Right

STOP 3. AKR TRUCKING COMPANY, 4288 Arthur Kill Road
The owner is Mr. Frank Agugliaro.
Prolific Pleistocene till overlies most of the older units on Staten Island and the age of these deposits are believed to be late Wisconsin (Roberts-Dolgin 1989). This exposure is approximately 1 mile north of the Terminal Moraine, which exists on the eastern part of Staten Island, extending from the Narrows to Tottenville. Sanders and Merguerian (1994) report red-brown till overlying decayed-pebble outwash, which rests on white, charcoal-bearing Cretaceous micaceous sands and gray clays. At this exposure, glacial outwash is present at the northern section of the driveway. The unit is a tan to red-brown sand, alternating with sandy gravel. The entire outcrop displays abundant trough cross-stratification, and existing rock fragments have an origin from the following sources:
1) Diabase and clastic sedimentary rocks from the Triassic-Jurassic Newark Super Group
2) Ironstone clastics of Cretaceous Age.
3) Granite-Gneiss Precambrian N.Y.-N.] . Highlands.
4) Lowerre or Poughquag Quartzite.
The source of these clastics may have been from the north or west.
The rock fragments show advanced stages of chemical weathering. Sanders and Merguerian (1994) believe that and the trough cross-bedding and the extensive chemical alteration indicates this unit was formed in a braided stream during the Early Pleistocene (Nebraskan).
Roberts-Dolgin (1989) concludes this unit is the Pensauken formation which represents a stream deposit formed during an interglacial period. It is suggested that the existing glacio-fluvial deposit is part of a delta that entered Lake Bayonne, a glacial lake that existed between the glacier and the Terminal Moraine. (Stanford and Harper, 1991).

STOP 4. The Conference House Park
Proceed past the conference house to the beach. The late Wisconsin aged Harbor Hill terminal moraine(see figures 2 and 5) is present in the cliffs facing the Raritan Bay. The typical unsorted, unstratified character of glacial till is exposed at this locality. The till is red-brown, with many large boulders intermixed with finer sediments in the moraine, as well as on the beach. The existing erratics display a wide variety in rock type, reflecting a source from the North or Northwest. They are examples of glacial outwash in several areas along the cliff. Merguerian & Sanders (1994) believe The Terminal moraine is Mid-Wisconsinan, (Sangamonian?) These authors believe that overlying the terminal moraine is a Paleosol, with downward extending zones of discoloration. They interpret these zones as tree roots.

B1: SEDIMENTARY ENVIRONMENTS IN THE NEWARK BASIN IN NEW JERSEY AND CONTIGUOUS
NY
Brooklyn College and Graduate School of the City University of New York
Brooklyn, New York 11210
and Northeastern Science Foundation affiliated with Brooklyn College of the City of New York
P.O. Box 746
Troy,
As Manspeizer (1988) noted "these are extraordinary times for Triassic-Jurassic researchers of the Atlantic passive margins. Extensive field studies on the African and North American plates during this past decade have yielded a wealth of new data and ideas about rift basins and the origin of passive margins, that but a few years ago would have seemed like childish speculation.
New surface and subsurface basins have been identified, fossils abound in strata that only recently were considered barren, oil exploration is being pursued actively in continental strata of the Richmond - Taylorsville, Sanford and Newark basins, Late Triassic marine strata have been identified in Georges Bank off the coast of Massachusetts, and the roles of wrench tectonics, successor basins and listric normal faults have challenged the classical view that these are simple extensional basins. Geologic data from the Atlantic passive margins record that continental rifting of central Pangaea occurred during the Late Triassic - Early Jurassic (Liassic), and that sea-floor spreading probably began no later than the Middle Jurassic.
The Newark Supergroup is composed of Late Triassic to Early Jurassic continental sedimentary rocks and interbedded basalts that crop out in a series of elongated basins along the eastern margin of North America (Froelich and Olsen, 1985).

B1: SEDIMENTARY ENVIRONMENTS IN THE NEWARK BASIN IN NEW JERSEY AND CONTIGUOUS
NY

STOP 1. Feltville Formation of the Newark Supergroup
On north side of Blue Brook are exposed interbedded micaceous red and gray siltstones and shales with sporadic lenticular channels of quartz sandstones. These exposed strata are part of the type section of the Feltville Formation of the Newark Supergroup. Similar exposures are present an estimated 1/4 to 1/2 mile farther east on south side of the brook, where a tributary meets Blue Brook. In the creek bottom are numerous blocks of quartz-pebble conglomerate.
According to Paul Olsen (personal communication, 1985) the strata at this site carry abundant spores and pollen.
For stratigraphic section see Table I. Figure 4 shows type section of the Feltville Formation exposed along ravine near Blue Lake; Table 2 provides the key for individual units.

Note exposures of Watchung Basalt, especially spectacular columnar jointing.

Note exposures of Watchung Basalt.

Ascend road to Scenic Overlook and return to Interstate 78.

STOP 2. Anthony Ferranti Quarry.
(Permission is needed to enter this quarry. _ Contact Linda Kimler, Public Relations, Anthony Ferranti Quarry, 908-647-8273).
Spectacular outcrops of sandstone, siltstone, and shale of the Feltville Formation occur beneath the Preakness Basalt (see Table I). Crossbedded sandstones show local channeling. Find sandstones with dinosaur footprints and plant fossils as well as raindrop impressions on mudcracked surfaces. Note small strike-slip faults in quarry.

Cuts on L side are in Palisades dolerite.

Cuts in dolerite, both sides of road.

End of cuts in dolerite.

Small dolerite cut on R.

Wooded hill in distance on R is Palisades sill
Wooded hill in distance on R is dip slope on W side of Palisades sill (strike NS, dip 150 W).

Exposure of dolerite of sill on R; overlain by sill.

Exposure of dolerite of sill in slope at R.

Barricade; passage for "Official Cars Only".
Park vehicles at barrier.

STOP 3. Nyack Landing, Upper Nyack
(SE part of Haverstraw 7.5 minute quadrangle, along W shore of Hudson River at Long. 73°54'W, from Lat. 41°08'15" to Lat. 41°07'30"N).
Walk southward on gravel road, along floor of old quarry in Palisades dolerite. Take trail toward Hudson River from S end of quarry. Walk down to lower level and study exposures along lower trail. The level of the old quarry floor lies at an altitude of about 60 ft; the top of the cliff facing the quarry is at an altitude of 510 ft. Thus the face is about 450 ft high. The face extends downward nearly to the contact with the underlying basal Newark sandstones. The contact is not exposed but lies near altitude +50 ft. The descriptions at this stop follow Friedman, Sanders and Martini (1982).
The continuous exposure of dolerite in the face is a noteworthy display of cooling joints, which are inclined off the vertical about the same amount as the base of the sill dips westward, i.e., 12 to 15°. At this locality, no olivine zone is exposed. Farther south the olivine zone, 10 to 15 ft thick, is located about 50 ft above the base of the Palisades sill. The absence of the olivine zone here could mean one of several things: (1) This exposure includes the lower 450 ft of the sill but no such zone ever formed here; (2) This exposure does not include the lowermost 450 ft of the sill, but that much of some part of the interior of the sill lying above the lowermost 60 to 70 ft, hence the olivine zone may be present but is not exposed in the old quarry face. Alternative 2 implies that a fault follows close along the base of the face and throws down on the west by at least 70 ft.
The large institution directly opposite us on the east side of the Hudson River is Sing Sing, the notorious destination of prisoners "sent up the river" (from New York City). The wide expanse of wooded countryside between Ossining and Tarrytown is the Rockefeller family preserve, an area so large that it has been incorporated as a separate town (Pocantico Hills). Nobody levies local taxes on the Rockefellers but other Rockefellers!
The Croton River enters the Hudson just S of Croton Point, to the NE of us. The till exposed on the tip of Croton Point itself has been interpreted by some as a lateral moraine, but we think this till is part of a drumlin having a N-S axis. Between the till and the mainland is a sandy deltaic deposit which formed when lake water occupied the Hudson Valley to altitude about +60 ft.
The sandstones exposed in a long strike section are situated about 1000 ft above the base of the Newark Group (Upper Triassic to Lower Jurassic)(based on projection from the section at the Tappan Zee Bridge). These sandstones probably belong to the Stockton Arkose (Upper Triassic to Lower Jurassic). The strata strike N20°W and dip 12°SW (determined on base of ledge overhanging the siltstone toward the S end of the exposure). Typical Stockton Arkose is a light gray pebbly coarse rock that contains large-scale cross strata indicating water flow toward the west. Such gray rock interfingers with red siltstones and sandstones containing less feldspar (or even zero feldspar), which form the Brunswick Formation. Farther SW the Newark sequence from base upward is Stockton, Lockatong, Brunswick. Lockatong, typically a tough black argillite deposit of a former lake, is not exposed north of the George Washington Bridge; the argillite disappears by interfingering with the sandstones and siltstones of the Stockton and Brunswick.
The bluff west of the trail exposes about 20 ft of strata, of which the thickest and most persistent unit is a maroon siltstone 6 to 8 ft thick. This unit is overlain and underlain by various sandstones. At the N end of the exposure only the overlying sandstones are present. These include (upward) a coarse pebbly laminated sandstone about 1 ft thick, a laminated, reddish medium-grained sandstone, 2 to 3 ft thick, and 6 to 8 ft of coarse-grained pebbly sandstone having prominent cross strata dipping (now) 28° toward the direction of S45°W (225° true on a 360° scale). The original dip of the cross strata is about 16°. Hence these are considered to be accretion-type cross strata (in the sense of Imbrie and Buchanan, 1965), of the kind that form by the advance of "washed-out sand waves" (features transitional between the "regular" sand waves of the lower flow regime and the plane-bed condition of the lower part of the upper flow regime).
Below the siltstone unit is a bed, 1 to 1.5 ft thick, composed of greenish, poorly sorted conglomeratic arkose, almost a "pebbly mudstone." Next below is a lenticular arkose having a maximum thickness of about 2 ft.
The interbedding of the siltstones and sandstones probably resulted from the action of a floodplain meandering river. One usually tends to expect such rivers to deposit the coarse sediments in channels and the fine sediment on the floodplain. As the channels migrate, a sheet of sediment is deposited consisting of what has been termed a point-bar sequence. This sequence begins with a channel-floor lag at the base and passes upward through various deep-channel and shallow-channel deposits whose thickness equals the depth of flow in the former channel. Such sequences have been much discussed under the heading of "fining-upwards cycles" (Allen, 1965b; also Friedman, Sanders, and Kopaska-Merkel, 1992).
Closely associated with this typical channel-migration succession are deposits of natural levees and fan-like bodies of coarse sediment that spread over the floodplain from crevasses in the levees where floodwaters erode a gap through the levees. These fans have been termed splay deposits (or crevasse splays). (See summary paper dealing with alluvial sediments by Allen, 1965a).
The upper sandstones west of the trail do not seem to be part of a typical fining-upward cycle deposited by a migrating channel. The laminated, medium-grained sandstone just above the siltstone may be a natural-levee deposit and the coarse, cross-bedded sandstone next above may be a crevasse-splay (idea suggested by John Connolly). The coarse sandstone forms a series of imbricate, overlapping lenses, the upper ones of which extend farther southward than the lower ones. Thus, instead of being incised into the siltstone as in a channel, these sands prograde over the siltstone as would the sediments of a growing fan (or the foreset beds of a delta lobe).
The sandstones underlying the siltstone are not exposed enough to be analyzed in detail. The lenticular sandstone, previously interpreted as a "double-channel" are here considered to be a depositional bedform having positive relief, a sort of longitudinal sandbar with the long axis parallel to the main direction of current flow. At the S end of the exposure sandstone and dolerite are in close juxtaposition. The sandstone lacks evidence of contact metamorphism and the dolerite is much too coarse grained for this contact relationship to be explained as intrusive. Accordingly, J.E. Sanders interprets this contact as a normal fault which strikes about NW, is nearly vertical, and throws down on the west by at least 70 ft; this much displacement is inferred in order to drop the olivine zone out of sight. Thus, J.E. Sanders presumes that the olivine zone is present, but is not exposed.

B2: SERPENTINITES OF NEW YORK CITY AND VICINITY
John H. Puffer
Dept of Geology
Rutgers Univ.
Newark, New Jersey, 07102
A discontinuous chain of early Paleozoic serpentinites are exposed along the Appalachian Mountains from Quebec Canada, through the New York City area, and into the southeastern states. The Geologic Map of New York, 1970, (Lower Hudson Sheet) shows five serpentinite bodies in the New York City Area: Staten Island, Hoboken, Manhattan, New Rochelle, and Port Chester that are part of this chain. The Staten Island and Hoboken serpentinites are the largest of the five bodies and are known to contain considerable asbestos (Puffer and Germine, 1994). The serpentinites of Staten Island and Hoboken consist of about 95 percent serpentine with minor but highly variable olivine, anthophyllite, talc, magnetite, and trace amounts of several additional minerals.
The chemical range is typical of metamorphosed harzburgite and dunite suites although some unusually low CaO and Al 2O 3 values may be due to hydrothermal leaching and re-precipitation as a network of amphibole and carbonate veins in shear zones.
The mode of emplacement of the New York area serpentinites is controversial but most evidence tends to favor the Taconic obduction of the base of a Iapetus ophiolite sequence. This would force the placement of the New York area serpentinites into the Taconic suture zone (Cameron's Line) between Hartland terrain (C-Oh) and Manhattan-C terrain (C-Om).
The chrysotile content of New York area serpentinites, as determined using a combination of polarized light and transmission electron microscopy and XRD techniques, is highly variable but is typically about 15 to 40 volume percent of the rock (Puffer and Germine, 1994). The widespread distribution of asbestos minerals in the serpentinites may lead to contamination of water and air supplies wherever exposures are being eroded.

B2: SERPENTINITES OF NEW YORK CITY AND VICINITY

STOP 1. STATEN ISLAND SERPENTINITE
Caution!! At the outcrop, stay on the unused roadway, do not go near I-278; watch out for falling rocks and do not attempt to climb loose rock faces.
This is the most extensive exposure of serpentinite in the New York City area. The serpentinite here contains variable amounts of relic olivine and minor amounts of anthophyllite schist. Both the highly foliated and the massive types of serpentinite are exposed here. The serpentinite exposed within a few cm of any of the closely spaced anastomosing shear planes visible on both walls of the road cut, tends to be green, highly foliated, and includes megascopically fibrous minerals. The rock furthest removed from the shear-planes is relatively dark-green to black and is massive.
An average mode based on 12 thin sections cut from the I-278 exposure is 88 % serpentine, (mostly lizardite and chrysotile), 3 % olivine, 2 % talc, 2 % anthophyllite, 3 % opaque oxide (mostly fine grained magnetite but also including coarse magnetite, chromite, and picotite), and 2 % carbonate (including dolomite and magnesite). About 1/2 of the serpentine is lizardite with highly variable concentrations of chrysotile ranging from absent to 70 % but averaging about 50 %. Minor antigorite is also present including the fibrous variety (picrolite, Benimoff and others, in prep). Olivine is commonly found in the massive, black rock typically as relic micro islands surrounded by serpentine that has replaced most of the individual grains. Talc and anthophyllite are typically found together as a coarse fibrous schist or less commonly as individual grains disseminated within the rock or in veins. The opaque oxides consist largely of the kind of finely disseminated magnetite that is typically expelled from olivine during hydration to serpentine. Olivine can hold more iron than serpentine so the excess iron is typically left as an intergrowth of magnetite and serpentine.
Chrysotile is not readily recognizable in most hand specimens or thin-sections of samples from this exposure. In thin section, only lizardite was recognized in one sample, but using transmitting electron microscopic (TEM) techniques (Puffer and Germine, 1994) abundant chrysotile was found.
Ten samples collected on the south side of the I-278 outcrop, spaced approximately 50 feet apart, were ground in a rock grinder, mixed, split and prepared on an EM grid. TEM point count data indicate a total chrysotile content of approximately 54 volume percent. Germine and Puffer (1994) also performed selected area electron diffraction analyses (SAED) and energy dispersive x-ray spectroscopy (EDEX) on several particles, confirming chrysotile as the major component and lizardite as comprising most of the remainder, with a minor talc component.
The same kind of analyses was conducted on another sample of serpentine from this roadcut (Sample 8p, Figure 4). It contains 38 percent chrysotile as confirmed by SAED and EDXS. The results were within the error range of the Puffer and Germine (1994) XRD estimate.
At least two varieties of massive chrysotile were recognized in samples of serpentine at the roadcut using TEM techniques (Germine, 1981). One variety is light to medium green and has a smooth fracture. It occurs in irregular masses and in veins ranging up to a centimeter in width. This type is composed of cross-fiber and randomly oriented fiber, and is often associated with abundant olivine. The second variety is a light green to white substance with pearly luster and platy to fine-grained meerschaum-like texture. This type of motive chrysotile occurs in veins, fracture fillings, and pore fillings. TEM examination indicates that it is composed of tubules with a diameter of 300 to 400 angstroms. Fiber lengths are generally less than 1 micron but also occur up to 5 microns (Germine, 1981).
Chrysotile with a megascopic fibrous appearance is much less common than massive varieties at this outcrop but occurs in veinlets typically less than 1 mm to 3 mm wide. The fibers are white to light green and silky. The veins readily fiberize and poses the flexibility that is a characteristic of all asbestos (Germine and Puffer, 1989). Asbestiform anthophyllite from this roadcut consists of straw-colored aggregates on anthophyllite fiber in association with gray to yellow-brown talc. The anthophyllite fibers range up to 18 cm in length in silky and splintery aggregates that are fairly rigid.
Slip-fiber veins of picrolite from this outcrop measuring 1 to 3 mm thick are also described by Germine (1981) and Benimoff and others (in prep.).

STOP 2. CASTLE POINT SERPENTINITE
This is probably the second most extensive exposure of serpentinite in the New York City area. The rock here is chemically (Table 2) and mineralogically indistinguishable from the 1-278 exposure but is more highly foliated. Most rock surfaces are bright green. Close inspection reveals common grains of chromite. The network of thin white veins are composed largely of magnesite. Minor quantities of talc is visible on freshly broken rock surfaces.
Some of the bright green serpentinite has a glassy gem-like appearance that is a variety called Williamsite. The Williamsite is composed of very fine-grained chrysotile.
Chemical analysis of four typical bright green samples from this exposure are consistent with meta-dunite although a two dark samples containing pseudomorphs of orthopyroxene are slightly richer in alumina and calcium and are interpreted as meta-harzburgite.

Field Trip Guide for the
69th Annual Meeting of the
New York State
Geological Association
Edited by:
Todd W. Rayne
David G. Bailey
Barbara J. Tewksbury
Clinton, NY
This guidebook was published by the New York State Geological Association. Additional copies may be obtained from the Executive Secretary of the NYSGA:
Dr. William Kelly
Executive Secretary, NYSGA
Rm. 3140, Cultural Education Center

A1: MADISON COUNTY DEPARTMENT OF SOLID WASTE LANDFILL FACILITIES
Paul W. Miller
Assistant Director
Madison County Department of Solid Waste
P.O. Box 27, Wampsville, NY 13163
General
Madison County runs a comprehensive solid waste and recycling program at its facilities located astride Buyea Road in the Town of Lincoln, Madison County, New York. Madison County is home to about 72,000 souls with numerous small villages and only one city, Oneida, with about 10,000 residents. Madison County contains the geographic center of New York State and is genuinely proud of its rural nature.
Two large abandoned marginal farmland properties have been used for landfilling activities since early 1973. Over time the changing regulatory requirements for solid waste management have necessitated numerous changes in construction standards for landfill facilities and environmental monitoring. Ideal geologic conditions have allowed operations to keep pace with changing requirements with reasonable economic investment. All expenses at the Solid Waste Department facilities are paid by user fees. No general tax revenue is used to support Department operations. In Madison County waste-pays-for-waste now but the changing world of solid waste management is creating economic pressures and challenges necessitating creative management.
One Field Trip Stop, but no Road Log

Madison County Landfill
The methods and procedures described provide a general overview of environmental and geotechnical drilling and sampling. These methods and procedures are used to provide critical subsurface data on many projects. The references that follow are just a partial list of the many publications currently available about Environmental and Geotechnical drilling.

A2: DRUMLIN-BLUFF AND BAYMOUTH-BARRIER EROSION ALONG THE SOUTHEASTERN SHORE OF LAKE ONTARIO, NEW YORK
Paul R. Pinet
Charles E. McClennen
email: ppinet@center.colgate.edu
email: cmcclennen@center.colgate.edu
The coastline of Lake Ontario has a long, complicated history of rapid morphologic development. The purpose of the trip is to examine the principal landform elements of this lakeshore sector -- drumlin bluffs and baymouth barriers (Fig. 1) -- in order to understand the shoreline's primary evolutionary history. Our focus will be on the coastal geomorphic changes that have occurred since the beginning of this century. The specific goals are 1) to assess our proposed model of coastal bluff evolution, 2) to examine the sedimentological interconnections between bluffs and baymouth barriers, and 3) to appraise the long-term impact (50-100 years) of engineered shore-stabilization structures.

A2: Drumlin-Bluff And Baymouth-Barrier Erosion Along the Southeastern Shore of Lake Ontario, New York

STOP 1. McIntyres Bluff and Environ
We will walk out to the edge of McIntyres Bluff in order to get an overview of this coastal compartment. BE VERY CAREFUL, BECAUSE THE EDGES OF THE BLUFF TOP ARE SUSCEPTIBLE TO COLLAPSE. Also, because the western end of McIntyres Bluff is private property with a home owner who values his privacy, we will confine our field inspection to the eastern half of the drumlin. Please comply with this request.
McIntyres Bluff is a north-south-trending drumlin. Note (Fig. 11) that the drumlin's axis lies oblique to the shoreline which east of Little Sodus Bay runs northeast-southwest. Gravel and sand eroded from the drumlin till are transported by longshore currents to the northeast and nourish a low-lying baymouth barrier. Notice how narrow the gravel and cobble beach is at the base of the bluff. This is due to two factors: 1) the lake level this past spring has been unusually high which has resulted in more beach erosion than usual, and 2) the gullies are not supplying much debris to the beach, as indicated by the dearth of mud flows that typically fill the V-shaped gully floors as well as by the absence of colluvial fans at the gully mouths. Nine years ago when we began our field studies of the southeast Lake Ontario shore, a well-developed colluvial terrace occupied the upper beach which at that time was much broader than at present due to the availability of sediment.
Features that are important to note as we inspect the gully network include:
i. the bowl-shaped head region of the gully system and its control by jointing;
ii. wet spots on the headwall that identify zones of groundwater seepage;
iii. the ubiquity of fresh slump masses at the base of the headwall;
iv. the steep-flanked ridges and narrow throat of the gullies;
v. the presence of mud flow deposits in the stretch of gully below the headwall, and of cobble and boulder lag deposits in narrow channels that are cut into the gully fill;
vi. the angularity of the large clasts in the till and mud flow deposits and the subrounded to rounded shapes of cobbles and gravel on the beach proper;
vii. the presence of a wave notch at the bluff's base and the development of a slump scarp running the full extent of the bluff.
Given the above morphological characteristics, what stage of bluff development does McIntyres Bluff represent?
Now we will hike along the beach to the east, in order to examine the morphology and sediment character of the downdrift baymouth barrier (Fig. 11). Note that the surface of the beach that runs the length of McIntyres Bluff is dominated by boulders, cobbles, and gravel, despite the large quantities of sand in the glacial till of the drumlin. Clearly, these coarse sediments are lag and storm deposits, the sand having been eroded and transported offshore by high-energy waves. Unlike ocean beach systems, there is no long-period swell in Lake Ontario, and fair-weather waves are incapable of transporting the nearshore storm-deposited sands back onto the beach (McClennen and Pinet, 1993). As such, the beach deposits are out of equilibrium with the fair-weather conditions that prevail along the lakeshore.
Note the numerous trees that have been uprooted and fallen as a consequence of the rapidly transgressing shoreline. During the past four years, this baymouth barrier has been relatively stable as indicated by our profiling surveys (Fig. 8C). This past spring, the barrier has been overtopped by storm waves forming overwash deposits. The onset of overwash along this barrier seems related to the unusually high lake levels during the past spring, in conjunction with a significant reduction in the amount of longshore drift due to the recent inactive nature of the gullies that are incised into McIntyres Bluff. Although McIntyres Bluff is in a mature morphological state, it is temporarily behaving as a bluff in old "age," because of the inactive nature of its gully system as indicated by 1) the lack of mud flow deposits and colluvial fans, and 2) the narrowness of the beach at the bluff's base. Presumably, the temporary reduction of sediment influx eroded from the bluff that supplies the coastal compartment is related to diminished groundwater seepage and surface runoff.
About 0.5 km from the eastern edge of Mcintyres Bluff (Fig. 11), we encounter a small bluff with a steep face and a wave notch. This small drumlin has just begun to be eroded by storm waves, and is a classic example of a bluff in a young stage of morphological development. Note the numerous fresh slumps at the bluff's base, the steep face (>45 degrees), and the presence of rills and a few channels etched into the bluff's surface. Given that the crest of this small drumlin does not rise more than 20 m above the lake level, which is slightly below the geomorphic threshold that we believe separates young from mature bluffs (Montesi and Pinet, 1997), we expect that it will not undergo extensive gully development as the drumlin is cut back by the advancing shoreline; rather it will remain a young bluff and eventually pass directly (i.e., bypass the mature and old stages) into the final terminal stage of morphological development. However, if the gullies of Mcintyres Bluff are reactivated and supply copious sediment to this downdrift barrier such that the beach widens substantially, then its possible that this small bluff will be protected from frequent wave attack, allowing the onset of gullying despite its small topographic stature.

STOP 2. Beach at Base of Drumlin to the W of Sitts Bluff
The lakeshore from this point westward to Little Sodus Bay (Fig. 9) has undergone extensive engineering in order to stabilize the shore of North Fair Haven and Fair Haven Beach State Park. The 1.5-km-long strand has been armored with jetties, seawalls, revetments, riprap, and groins. All of these structures are accessible by walking along the beach to the west. If we look to the northeast, we can see Sitts Bluff with its towering, unvegetated cliffs (Fig. 9). To the southwest, we can see a large drumlin that lies within the State Park. Note that it is vegetated and is stabilized by a revetment along the shore.
After examining a groin (pier) that has been reattached to the shore with riprap, we will proceed to the northeast in order to examine a baymouth barrier that is retreating at a rapid rate, at almost 2 m/yr (Figs. 9 and 10). This is not surprising, given that the net longshore drift is to the east and the barrier lies downdrift of jetties and groins, and that the base of the two bluffs between The Pond and the baymouth barrier are protected by seawalls, riprap, and revetments. This section of the lakeshore is sediment starved. Therefore, the baymouth barrier is retreating landward rapidly as storm waves overtop the beach ridge causing extensive overwash. Note the well-rounded character of the beach material.
One reason why we believe that at least segments of the southeastern Lake Ontario shoreline consist of discrete coastal compartments is that sediment starvation here is confined to the drumlin bluff-baymouth barrier couplet. Downdrift of us lies Sitts Bluff, an unprotected drumlin in a late mature stage of morphological development that is supplying coarse sediment to its down drift baymouth barrier. Our beach-profiling studies (Fig. 8) indicate clearly that the barrier to the east of Sitts Bluff has been in a quasi-equilibrium state since 1950, and has not retreated appreciably in contrast to the barrier that we are currently examining. In other words, the past 50 years of severe sediment starvation that characterizes the segment of the lakeshore that we are now examining has not affected the adjoining downdrift compartment, suggesting that bluff-barrier couplets are self-contained entities to a large degree.

STOP 3. Chimney Bluffs
Chimney Bluffs (Fig. 12), an undeveloped State Park, is located about 22 km to the west of Stop 2 (Fig. 1), and about 3 km to the east of Sodus Bay. This excursion adds a considerable amount of time (1-2 hrs) to the trip. Chimney Bluffs is a high, broad drumlin with enormous, deeply-incised gullies that are unusually long for the Ontario lakeshore. According to our classification, it looks to be in a very late mature stage of morphological development, as judged from its appearance on topo maps (almost half of the drumlin has been eroded) and clear signs of old "age" in the field. As we walk along the beach to the west, note how the steep, planar, low sides of the bluff which are controlled by gravity slides are replaced by small and then large gullies as the bluff height increases toward the drumlin's center. Also, note that the gully floors are devoid of thick accumulations of mud flow deposits. However, there are remnants of colluvial fans at the gully mouths that have been eroded back by waves to the bluff face; observe how difficult it is to distinguish glacial till from mud flow deposits which grade into one another at the gully mouths. Wave notching and a slump scarp at the bluff's base are clear evidence of a lack of sediment supply to the adjoining beach. If our interpretation that Chimney Bluffs is in the old stage of morphological evolution is correct, we expect that the rate of retreat of the top surface of the bluff will diminish with time, whereas recession of the base of the bluff will likely accelerate as the sediment supply to the beach is reduced, allowing storm waves to undermine the bluff and cause increasingly more slumping with time.
As we approach the west flank of the drumlin, we will encounter varved lake sediments deposited in glacial Lake Iroquois. Typically the varves are millimeters thick, and alternate between clay-rich and silty sand-rich laminations, the former representing low energy winter conditions when the lake surface was frozen, the latter higher-energy conditions associated with spring melting. Ice-rafted dropstones are common. Some of the varve sequences are distorted, crumpled into tight folds, that represent either soft-sediment deformation, iceberg keel groundings, or minor glacial ice readvancements during the retreat of the Ontario Lobe of the Laurentide Ice Sheet.
We can return to our vehicles by climbing up the bluff along a crestal trail which provides a superb panorama of the gullies, embayments, fans, and beach and nearshore features. BEWARE OF TREACHEROUS FOOTING AND UNSTABLE CLIFF EDGES. If you prefer, you may return to our starting point by retracing your steps along the beach. For those of us hiking the ridge line, note the appearance of the gullies from above and the nature of the shoulders of adjoining gullies. Also, the map view of Chimney Bluffs shows a flat top to the drumlin, a feature that is attributed to wave planation when the drumlin was immersed beneath Lake Iroquois. Support for this interpretation is provided by irregular lag deposits of gravel that are visible at the very top of some of the gully headwalls. Presumably, the glacial gravel was sorted and the pebbles were rounded by shallow-water wave activity on this former shoal which at that time was located several kilometers offshore of the southern Lake Iroquois shore.

A3: TIMING OF INTRUSION, ANATEXIS, AND METAMORPHISM IN THE PORT LEYDEN AREA OF THE WESTERN ADIRONDACKS
Frank P. Florence
Science Division, Jefferson Community College
Watertown, NY 13601
frank florence@ccmgate.sunyjefferson.edu
Robert S. Darling
Dept. of Geology, SUNY College at Cortland
P.O. Box 2000, Cortland, NY 13045
darlingr@snycorva.cortland.edu
The purpose of this field trip is to examine evidence of the igneous, metamorphic, and tectonic history of the western Adirondack Highlands preserved in rocks in the vicinity of Port Leyden, NY. We will visit and discuss rocks and structures at six sites that include interlayered metasedimentary and metaigneous lithologies and a distinctive nelsonite (apatite-magnetite-ilmenite) dike. Rocks at these sites display structural fabrics and crosscutting relationships formed through a sequence of metamorphic, hydrothermal, and melting events. Recent geochronological studies confirm that this area has undergone a complex tectono-thermal history.
In particular, this trip will focus on uncertainties concerning the anatectic or intrusive origin of leucogranitic gneisses and melt veins in the gneiss surrounding the nelsonite dike. By clarifying structural and field relationships, we hope to discriminate between interpretations of igneous activity and metamorphism in these gneisses. Potentially, this may establish useful constraints on regional interpretations of orogenic sequence.
Trip Objectives
This trip highlights some of the controversial structural and chronological relationships among rock units. When visiting the stops on this trip, you are encouraged to consider these questions:
1. What was the timing of penetrative deformation and to what extent, if any, can mineral assemblages and textures formed during the intrusion of the AMCG suite be recognized in the Port Leyden area rocks?
2. Unstrained phases that crystallized from melts occur in veins, reaction zones, and in equigranular granitic rocks. Is granitic intrusion implied by these features? Which features might be anatectic? Can anatexis explain the 1032 Ma zircon age date from granitic gneiss?
3. Are the quartz-sillimanite nodules and stringers (or their protoliths) relatively early features that were present in the surrounding gneiss prior to penetrative deformation or did they form relatively late due to hydrothermal activity in a crystallizing magma?
4. Did pegmatites originate from late-magmatic fluids at the time of granite intrusion or are they a result of fluids evolved from in situ rocks at the time of the peak of metamorphism?
5. What tectonic significance can be placed on the moderate (vs. high) pressure estimates obtained from this region of the Adirondack Highlands?

A3: Timing of Intrusion, Anatexis, and Metamorphism in the Port Leyden Area of the Western Adirondacks

Low roadcuts of Ordovician Black River Group limestone.

Barrett quarry.

View of historic Black River canal quadruple locks.

STOP 1. Rt. 12. Calc-silicate and Aluminous Metasedimentary Rocks
These rocks comprise one of two narrow but mappable bands of calc-silicate gneiss that extend northeastward, under the Pleistocene deltaic sands, and reappear along the Moose River (Fig. 1). Foliation in both calc-silicate bands strikes northeast and dips moderately northwest.
A variety of bulk compositions can be observed in this exposure, but the dominant minerals are clinopyroxene, biotite, K-feldspar, and quartz. Other minerals include grandite garnet, titanite, wollastonite, calcite, and scapolite. Compositional data are limited, but EDXF spectra from the garnet show mostly grossular with a small andradite component. The scapolite is mostly meionitic. In thin section, the margins of wollastonite grains contain thin rims of retrograde garnet identical to that described by Valley et al. (1983) from drill cores just 3.0 kilometers NE of this location. This garnet is unusual because it contains stoichiometric fluorine (up to 0.76 wt.%; Valley et al., 1983). Wollastonite occurs in apparent textural equilibrium with calcite and quartz.
As noted in some other Adirondack marbles, the occurrence of regional metamorphic wollastonite suggests an H2O-rich fluid composition (Valley and Essene, 1977; 1980b). We interpret these rocks similarly. Specifically, at the PT conditions in this region (700-750 °C and 4-6 kbar), a fluid composition of XH2O ≈ 0.80-0.90 is necessary to stabilize these minerals (Jacobs and Kerrick, 1981). The margins of some quartz ± pink K-feldspar veins are characterized by an assemblage of epidote + specular hematite, suggesting a higher O2 fugacity compared to that in the country rocks.
At the northernmost part of the roadcut there is a small exposure of leucocratic K-feldspar + quartz + sillimanite gneiss. Minor amounts of biotite, magnetite and almandine garnet occur locally. The presence of matrix sillimanite in these exposures, coupled with the bulk composition of the calc-silicate gneisses, strongly argue in favor of a sedimentary origin for both rock types.

STOP 2.Leucogranitic Gneiss with Quartz-Sillimanite Stringers
Outcrops in the woods on both sides of the road consist of relatively homogeneous, granitic gneiss. Abundant, cm wide stringers of quartz and sillimanite, with minor oxides, biotite, and garnet, are distributed throughout these rocks. Orientation of these stringers parallels the gneissic foliation defined by biotite and oxides, which locally varies between N20E and N50E. These exposures lie within a 1.5 km wide band of leucogranitic gneiss that can be traced N40E from the Black River to exposures along the Moose River at Lyonsdale (Fig. 1).
Immediately west of the road, and about 5 m uphill, are a few exposed knobs that also contain quartz-rich layers (leucosomes?) parallel to foliation. Biotite and magnetite occur in mm thick margins on these layers. Note that tight to isoclinal folds deform the quartz layers and are parallel to foliation and the quartz-sillimanite stringers.
Walk across to the east side of the road, enter the woods, and continue walking to the northeast for about 100 m to where a large dome of pink, granitic gneiss is exposed. On the southwest side of the outcrop there is a boudinaged quartz pegmatite layer. Sheared layers of leucogneiss parallel the margins of the boudin and flow inward around the necks. Coarse K-feldspar, possibly precipitated as a melt or hydrothermal phase, extends from margins through the pegmatite. Boudin margins contain bladed sillimanite, biotite, and magnetite. Additional folded and disrupted quartz veins are displayed around the right side of the outcrop.
Quartz-sillimanite stringers are distributed throughout the rock. Their orientation relative to penetrative deformation is well displayed across the top of the dome, where these features can be seen to form parallel to the plane of foliation. NE trending isoclinal folds deform some quartz-sillimanite segregations.

Outcrop of leucogranitic gneiss.

STOP 3. Lyonsdale.
Metapelitic Gneiss, Leucogranitic Gneiss, Sillimanite Nodules, and Undeformed Pegmatites
Walk down to Moose River. Follow trail upstream approximately 250 m to northward bend in river. Continue around bend, then walk down to the river's edge to metapelitic gneiss.
The river's orientation through this scenic section is parallel to lithologic layering. A low angle wall of homogenous quartzofeldspathic gneiss is exposed across the river. Garnet-rich metapelitic rock (kinzigite) is exposed for over 200 m along strike on this side, close to the water's edge. There is a sharp compositional boundary between the metapelitic gneiss and adjacent leucocratic gneiss about 5-15 m away from the river. From this contact back to the bridge, the gneiss contains less biotite and garnet.
A meter scale isoclinal fold is exposed in the metapelite layer on the southern end of the outcrop, with fold layers made up of gray, biotite-rich and pinker, perthite-rich layers. Garnet is ubiquitous; some layers contain coarse garnets > 1 cm. Elsewhere, pods of abundant small garnets form in quartz veins. Sillimanite is distributed throughout some layers and absent in others. Florence et al. (1995) found undeformed melt veins along grain boundaries locally in the metapelite. Small (0.1 mm) inclusion-free, euhedral garnet neoblasts occur with plagioclase and K-feldspar-quartz segregations surrounding embayed biotite. These textures indicate partial melting according to the biotite-dehydration reaction: Bt + Sill = Grt + Kspar + melt.
Walk back towards the parking area along the trail. Notice the pink leucogranitic rock at the canoe launch by the bridge. This gneiss clearly displays nodules of quartz and sillimanite. Two orientations can be observed, and a deformed pegmatite is seen to truncate and cross-cut the quartz-sillimanite veins.
Return to the road, cross it to a dirt road, and walk along the road in the downstream direction. After about 100 m, walk left through the woods and out onto a broad exposure of orange-pink, perthitic, leucogranitic rock with many quartz-sillimanite stringers, veins, and lenses. At least two orientations of quartz-sillimanite veins are displayed here: N50E veins are cross-cut by N20E veins (Cunningham and Willis, 1996). En echelon gash veins indicate extension and rotation within a shear zone and some small-scale granite melt veins truncate quartz-sillimanite veins. Deformed pegmatite and quartz layers are common. Large (0.5 m width), undeformed pegmatites dated at 1027 Ma cross-cut all other features.
Scattered calc-silicate inclusions are present in the gneiss throughout the outcrop area. 250 m below the bridge, biotite-rich and garnetiferous horizons become common. These layers contain sodic plagioclase, as well as microcline. Quartz-sillimanite nodules are absent in these layers, although sillimanite is present in the rock. Notice that quartz-sillimanite nodules reappear in pink, leucogranitic layers.
Postel (1952) and Whitney and Olmsted (1988) have described rocks in the northeastern Highlands that are similar to the leucogranitic gneiss. Whitney and Olmsted (1988) referred to these rocks as the Lyon Mountain Gneiss and interpreted them to be metamorphosed products of altered volcanic rocks and interlayered basin sediments. Chiarenzelli and McLelland (1990) suggest the alternative hypothesis that the interlayered lithologies may have been the result of "emplacement of sheet-like intrusions combined with high strain to yield tectonic layering." If the leucogranitic gneiss at Lyonsdale is properly correlated with Lyon Mountain Gneiss, then correctly establishing its origin is has regional consequence.
Undeformed pegmatites cross-cut all lithologies in this area. These demonstrate fluid flow at and immediately after the peak of granulite facies metamorphism and anatexis, or during late crystallization of granite intrusives. If the PT estimates of Florence et al. (1995) represent conditions of granulite facies metamorphism, then these dikes likely formed under thermal and stress conditions that permitted fractures at between 4 and 6 kbar pressure.

STOP 4. Agers Falls. Leucogranitic Gneiss
Extensive outcrops of leucogranitic gneiss are exposed along the Moose River in this vicinity. This is the same leucogranitic gneiss seen upriver at Lyonsdale, although here it appears more homogeneous. The rock is composed largely of quartz and perthitic feldspar, with minor amounts of iron oxide, biotite, sillimanite, and garnet. Through much of the outcrop the rock has an equigranular texture and is largely lacking a gneissic fabric. Numerous pegmatites and coarse, irregular granite veins transect the gneiss.
Scattered grains or cm long veins of sodic plagioclase are recognizable in thin sections from this exposure. Plagioclase is sometimes myrmekitic and commonly exhibits erose grain margins, suggestive of resorption. Locally, oxide grains surround plagioclase margins. Garnets are almandine-rich and show irregular grain margins. Some garnets are surrounded by small biotite grains. This texture suggests the retrograde reaction: Kfs + Grt + H2O = Bt + Sill.
Elongate and nodular quartz-sillimanite segregations are abundant throughout the outcrop. Two sets of nodules are recognizable: one is aligned with the NE trending regional structure and a second, cross-cutting set is oriented at about N20E. Discontinuous layering defined by these features sometimes exhibits swirl patterns. Hercynite spinel is commonly present in the quartz-sillimanite segregations.
The single zircon grain dated at 1031± 8 by Orrell and McLelland (1996) was collected at this outcrop. They describe the sample grain as clear and prismatic and the determined age is concordant. They consider the leucogranitic gneiss to be a late- to post-tectonic intrusion emplaced into relatively shallow crust. Essentially all vein features are viewed as having formed during a single hydrothermal event that accompanied and ultimately outlasted magmatic intrusion. In this interpretation, the quartz-sillimanite features must have formed at about the time of emplacement or closely afterwards, when the intrusion was still partly molten or at a temperature sufficiently high to permit ductile deformation.
Our alternative interpretation suggests that anatexis of in situ lithologies has produced the many magmatic features observable in the Port Leyden region and that the zircon age reported by Orrell and McLelland (1996) dates the formation of granite veins in this rock. The quartz-sillimanite±spinel veins and nodules are considered to be relict features that have been rotated into their current configuration. The zircon age obtained at this outcrop and mineral ages from nearby sites define the time of a widespread thermal event that coincided with the development of the pervasive fabric and compositional layering seen at the regional scale. It needs to be emphasized that other zircon grains from here and at Lyonsdale demonstrate that cores and overgrowths do not record the same ages. Abraded cores yielded ages up to 1119 Ma that Orrell and McLelland (1995) view as inherited from older granitic rock present in the magma source region. We consider it more likely that these older zircon ages reflect crystallization within this crustal horizon in response to an earlier episode of igneous or metamorphic activity.

Low outcrop of foliated, pink and gray felsic gneiss.

STOP 5. Goulds Mill, Quartz-rich Gneiss
Walk along a dirt road parallel to the river for approximately 50 m, then cut down through trees to broad exposures along the river banks. A quartz-rich unit is exposed beginning under the bridge immediately below the dam and continuing downstream for over 50 m. Locally, the rock appears to be conglomeratic. In other places, it gives the appearance of being composed of many parallel quartz veins. The rock displays a red to yellowish coloration indicating presence of hematite and iron hydroxides. Portions of the rock are tinted green, probably due to formation of chlorite. Weathering of sillimanite and/or feldspar has produced a white wispy streaking throughout the rock.
Downstream from the bridge sillimanite needles occur in a quartz-rich matrix. Individual grains are often aligned with the dominant fabric in the rock. Some coarse sillimanite also forms fan-shaped sprays. Some pegmatites and potassium feldspar-rich veins are aligned with the rock fabric. Also present are relatively undeformed pegmatite veins that cross-cut lithologic layering. These veins contain commonly potassium feldspar and sillimanite associated with quartz.
The protolith for this quartz-rich gneiss is uncertain. Possibilities include arkosic sandstone, hydrothermally altered felsic volcanics, or a hydrothermally altered felsic intrusion.
Possible brittle deformation features crop out on the right (northern) side downstream of the bridge. A continuous 1 to 5 m thick, apparently horizontal rock layer displays a crackled texture, in contrast to the massive character of the rock on either side. This layer cross-cuts the steeply NW dipping foliation. Cm scale patches of dark colored, cryptocrystalline material is present on outcrop surfaces and along small scale joints or shear planes. Currently, studies are underway to determine the composition of this material.

STOP 6. Port Leyden. Nelsonite Dike and Metapelitic Gneiss
This is the only described occurrence of titanium-rich nelsonite that does not occur within or in close proximity to large volumes of anorthositic rocks. Because of the strong field and experimental evidence supporting the formation of nelsonite by magmatic immiscibility during evolution of anorthosite suite rocks, we infer that anorthosite must have once been present in the western Adirondacks.
From the parking spot, cross to the south side of the road, walk over a rounded outcrop with quartz-sillimanite nodules and stringers, and down to the left. Continue walking for approximately 40 m to the southeast. Notice the low outcrops of foliated , light pink pelitic gneiss along the way. Abrupt transition to dark rocks delineates the contact with the nelsonite. Look at your compass to see the effect of standing over a body of rock that is about 40% magnetite! Good specimens of nelsonite material may be obtained from the waste pile on the south side of the mine shaft.
The nelsonite occurs as an elongate, nearly parallel sided body. Width is between 3 and 4 m and the dike is 30 m along strike at the surface. Contacts with the surrounding metapelitic gneiss are generally sharp, and locally parallel to foliation. At the northern end of the dike, the contacts truncate regional foliation defined by quartzofeldspathic layering. Detailed mapping and geophysical studies indicate that the nelsonite strikes north-south and has a near-vertical dip (Laforce et al., 1994). This attitude cross-cuts the N30E to N50E foliation in surrounding outcrops of gneiss.
The rock is equigranular and homogenous except towards the margins, where the relative abundance of pyrite increases shows a weak foliation. Garnet crystallizes interstitially to magnetite and apatite at the expense of ilmenite in this zone. A silicate-rich, 5 cm wide outer portion of the contact zone contains abundant plagioclase and is essentially sillimanite-free. A variety of textures indicate that plagioclase crystallized from a melt, including myrmekitic and symplectic plagioclase, and intergranular veins of plagioclase with associated magnetite. Anorthite content in plagioclase decreases with distance away from the dike margin. This suggests plagioclase grew in response to apatite breakdown and Ca flux outward from the dike. A model whole rock reaction for the contact zone is Mag + Ap + Hm + perthitic Kfs + Qtz + Sill = Grt + Mnz + titaniferous fluoro-Bt + PI-rich melt.
Florence (1997) proposed that halogen release associated with apatite breakdown lowered the solidus temperature, leading to partial melting. Did this melting event occur at the time of nelsonite intrusion or during later granulite facies metamorphism?

A4: STRATIGRAPHY, SEDIMENTOLOGY, AND GEOCHEMISTRY OF SENECA LAKE, NY
John D. Halfman
Department of Geoscience
Geneva, NY 14456, halfman@hws.edu
Donald L. Woodrow
Geneva, NY 14456, woodrow@hws.edu
The purpose of this field trip is to look at the stratigraphy, sedimentology and Chloride geochemistry of Seneca Lake, and how they relate to deglaciation of the area. Our field trip (cruise), aboard the H-WS Explorer, will focus on representative sediments that have accumulated in the northern part of the lake since deglaciation which are typical of what is found in the other Finger Lakes. We will also highlight our ongoing efforts to collect and interpret high-resolution (2 - 12 kHz) seismic reflection profiles that image down to the glacial drift, and highlight Mike Wing's and Bill Ahrnbrak's recent understanding of the high chloride concentrations in Seneca Lake in comparison to the other Finger Lakes.
The Finger Lakes of central New York State consist of 11 elongated, north-south trending basins just south of Lake Ontario (Fig. 1). The basins are glacially scoured into the northern edge of the Appalachian Plateau (Coates, 1968. 1974). At Seneca Lake, the bedrock is primarily Devonian shales (Hamilton Group in the northern end of the lake), and lesser amounts of sandstones and carbonates that gently dip to the south-southwest. Silurian carbonates, shales and most importantly evaporites (mostly halite) are found below the Devonian section.
Seneca Lake is the largest (by volume) and deepest of the Finger Lakes (Fig. 1, Table 1). Only Cayuga Lake immediately to the east of Seneca is longer (61 km) and almost as deep (132 m). The other basins are smaller. ranging in length from 5 to 32 km and maximum water depth from 9 to 84 m. The present day lake is drained to the north-northeast through the Seneca River (New York State Cayuga-Seneca Barge Canal).
Cruise Log
This field trip starts and stops aboard the H-WS Explorer, and investigates the sediment character and water chemistry at selected locations (Fig. 1). We will look at the X-Star seismic stratigraphy of the sediments while underway between stations. Surface grab samples will be collected at the first two stops, and a short piston core at the third stop. We will also deploy the CTD and collect water samples to analyze at the third station as well. We will not concern ourselves with the lacustrine marls because they compose a small fraction of the sediments in the lake.

STATION 1. Shallow-Water Sandy Silts
Northern end of Seneca Lake
The lake floor is covered by sandy silts, with the coarsest sediments in the northwest margin of the lake. Shell and plant debris and the occasional ice-raft pebble make up the other minor components. We believe that these sediments must be derived from the reworking of and erosion of glacial drift. Sub-bottom images suggests that the sand forms a thin wedge of sediment above the pink clays and/or glacial drift. In many places the seismic images are attenuated by gas (biogenic methane?).
Suitable substrate (coarse materials) is covered by zebra mussels. Zebra mussels are an exotic species that has been recently (1991?) introduced in the lake. They are prolific filter feeders, filtering, on average, a few liters of water each day, extracting the plankton from the water column. One possible measure of their impact is historical Secchi disk data. Secchi disk are used to measure water clarity. To a first approximation, deeper Secchi disk depths correspond to less turbid water (e.g.. smaller plankton concentrations). Historical Secchi disk data have shown increasing Secchi depths over the past decade from a few meters to over 5 meters deep during the productive early summer months. This change is consistent with a decrease in chlorophyll concentrations. The exact reasons for the increase in water clarity (and decrease in chlorophyll) are not completely understood but the Secchi disk data suggests two hypotheses: that the burgeoning population of zebra mussels has become large enough to significantly reduce the standing crop of plankton, and/or an increase in the quality of sewage treatment by lake-shore residents has reduced the anthropogenic "nutrient loading" to the lake.

STATION 2. Proglacial Rythmites
Offshore of Belhurst Castle - Geneva Country Club
To the south of station 1, pink clays may be found below a thin veneer of postglacial material. The pink clays are well stratified, very cohesive and exhibit light red to pink colors. Single pebble to granule sized grains and ostracode shells are found widely scattered in the sequence. Well defined, parallel to subparallel reflectors characterize these clays in the sub-bottom profiles. The reflectors commonly outcrop onto the lake floor in shallow water. We interpret these clays as proglacial rythmites, typical of many proglacial lakes. It is unclear whether the couplet are annual events (varves). In the northern part of the lake, the pink clays are folded. The subbottom profiles suggest that the pink clays collapsed into ice-block holes in the underlying drift and/or the ice front experienced small readvances

STATION 3. Postglacial Muds & Lake Geochemistry
Offshore of Clarks Point
Moving south across exposures of glacial drift, the lake floor descends to a flatter floor typical of the deeper parts of the lake. At this location the sediments are very fine grained, black to gray, stratified and rich in organics. These sediments blanket the older materials with thicknesses up to 8 meters in the sub-bottom profiles. The sequence thins rapidly in water depths shallower than 60 meters and on the steep slopes on either side of the basin. They contain no shell material, a few coarse grains of silt and sulfide minerals. These muds are interpreted as the postglacial sediments deposited since deglaciation. The source is the suspension of fine material carried into the lake by streams and/or erosion of older, shallow-water bottom sediments by surface and internal waves.
We will also deploy the CTD and analyze the surface water for its chloride concentration to discuss the source of the "extra" Chloride to Seneca Lake.

A5: CAMBRO-ORDOVICIAN AND MODERN CARBONATE FACIES OF THE MOHAWK-HUDSON VALLEYS, NEW YORK
Department of Geology, Brooklyn College and Graduate School of the City University of New York
Brooklyn, NY 11210
and Northeastern Science Foundation affiliated with Brooklyn College
Rensselaer Center of Applied Geology
15 Third Street
gmfriedman@juno.com
A shallow epeiric sea covered most of the North American continent. The shallow water limestones and dolostones that accumulated on this platform make up the Upper Cambrian, Hoyt and Galway formations and the Lower Ordovician Tribes Hill Formation that we will examine during this field trip. These carbonates were deposited in a roughly east-west belt at 20° S latitude. Quartz sand and dolomite were deposited in varying intermixed quantities (Galway Formation) with localized algal reefs (Hoyt Limestone) fringing the southern Adirondack shore. The limestones and dolostones of the Tribes Hill Formation were laid down along the eastern edge of the craton about 35 miles west of the shelf edge. As they were deposited close to the shelf edge they were affected by the tidal fluctuations of the adjacent waters of the deep ocean. To the east of the platform, deep-water shales and carbonate clast conglomerates accumulated on the continental slope and rise.
The end of Early Ordovician time is marked in the rock record by the Knox unconformity which exposed the broad continental shelf. In Middle Ordovician, the Taconic Orogeny was initiated followed by the Acadian Orogeny in the Devonian and the Alleghanian Orogeny in the Late Carboniferous with intervening periods of quiescence and carbonate deposition. The eastern edge of the craton was subjected to deformation during the Appalachian orogenies but in the region of the Mohawk Valley and Saratoga Springs of the present field trip, the Cambro-Ordovician platform strata are relatively undeformed. Figure 1 is a map showing the field-trip route marked with the location of the stops.

A5: CAMBRO-ORDOVICIAN AND MODERN CARBONATE FACIES OF THE MOHAWK-HUDSON VALLEYS, NEW YORK

STOP 1. Modern Nonmarine Limestones (Travertine)
This stop can also be reached through the Main Gate of the State Park on Route 9.
Route of Walk
Walk downhill into a small wood with picnic tables towards a stone building. Bicarbonate-charged, saline waters issue from a faucet at the side of the building and pass through a pipe below dirt road, re-emerging on the bank of Geyser Brook. Calcite precipitates on the steep slope of this bank, forming a terrace of travertine. The water is known as Orenda Spring and the terrace as Orenda Terrace; we will get a better view of this terrace later from below. A walk of a few hundred feet along dirt road leads to the Hayes Well Spring at bridge across Geyser Brook. A taste of this water is "rewarding" for its initial effect. Prolonged drinking is not recommended. From Hayes Well Spring you see the Island Spouter "Geyser" a few hundred feet upstream. The water of this fascinating "geyser" is from a well; the water spouts from a small orifice to a height of about 30 feet. This well was drilled about 80 years ago and the large cone of travertine has formed since.
Follow the path along Geyser Brook upstream. In the bank on the left is an exposure of Middle Ordovician Canajoharie Shale, an outer shelf to slope facies. On occasion, graptolites can be found in this shale. Continue to Orenda terrace to study travertine (Fig. 2). Note the rippled surface of the travertine and the brown iron-oxide coloration that occurs in streaks. Up to approximately 4 cm of calcite may precipitate annually at the foot of the terrace. Note "caves" and dripstone at far end of terrace and search for calcite-coated twigs and leaves or impressions of leaves in the travertine. Pisolites occur in abundance on the walkway between travertine cone and bank of brook. Spheroids and ooliths are likewise present (Schreiber et al. 1981).
Discussion
Although in the classical studies on limestones, including the authoritative work of Pia (1933), nonmarine limestones are accorded some measure of importance, the literature on modern carbonates neglects nonmarine carbonates. At this stop you'll see an excellent example of travertine, a rock which, like reef-rock, crystallizes in an initially stony condition.
The term travertine is derived from the Italian word, travertino, a corruption of tiburtino, "the stone of Tibur", which is a former name of the locality now called Tivoli (see Sanders and Friedman, 1967, p. 176). The type locality at Tivoli has been classically described by Lyell (1830, p. 207-210) and Cohn (1864). Some authors make a sharp distinction between the terms travertine, tufa and sinter: others use these terms synonymously (Pia, 1933; Gwinner, 1959, Sanders and Friedman, 1967, p. 176).
Travertine in Saratoga Spa Park gathers around the orifice of wells, on terraces from which water descends, or as a cone around a "geyser". Waters enriched in calcium bicarbonate issue from the subsurface, lose their carbon dioxide and insoluble calcite precipitates:
2HCO3- + Ca++ ↔ 2CaCO3 + CO2 + H2O
Twigs and leaves of beech, maple, and oak are preserved as they become coated with calcite or leaves form impressions in the travertine. The calcium bicarbonate-enriched waters originate nearly 1,000 feet below the surface in the underlying Cambrian-Ordovician limestones and dolostones, especially in the Gailor Dolomite. The waters are confined as in an artesian well beneath a thick cover of impervious Canajoharie Shale from which drilling recovers them. In the early years, the springs issued from natural crevices in the rocks, particularly from the prominent MacGregor fault. Later, pits were dug; the present wells flow through pipes set in bore holes.
The composition of the Saratoga mineral waters is unique among waters that precipitate travertine (Back et al. 1995; New York State Department of Health 1959; Young and Putnam 1979). Most waters that make travertine, especially those of the classical areas in Europe, drain areas of karst, and are of low salinity. By contrast, analyses of Saratoga waters give salinities that geologists classify as "brackish" (approximately 11%). Inspection of tables of analyses (e.g. Kemp, 1912) indicates the closeness of the composition of these waters to that of formation waters. This is especially true of the high concentration of NaCl. As the waters in the subsurface apparently dissolve limestones and dolostones, the concentration of the calcium, magnesium, and bicarbonate is higher than that of many formation waters. As in most formation waters, the sulfate content is low. Although the origin of the mineral waters is controversial (Hewitt, McClennan, and Nilsson, 1965), this controversy parallels that of the origin of formation waters. The mineral waters are probably formation waters whose salinity has been lowered as a result of mixing with meteoric water.
Newly precipitated calcite from the Orenda Springs gives a strontium isotopic value of 0.716429 (10) 87Sr/86Sr (± 2 S.D.)*, a continental crust signature (Fig. 3). If the waters were derived Upper Cambrian formation water, an Upper Cambrian seawater signature would have been obtained (see Fig. 3). According to Siegel (1996) carbon isotopic analyses likewise hint that the carbon may be expelled from the mantle
* The Sr analyses are normalized to 86Sr/88Sr = 0.11940.
Analyses of NBS 987 averaged 0.710241 (09) (n = 39) during the period of these analyses.
Errors on 87Sr/86Sr are given as 2 sigma (95%) in the last two digits.
The aquifer containing the mineralized water is under carbon-dioxide pore pressures which are estimated to be as high as five atmospheres that spew mineral water and gas several meters high (Siegel 1996). The acidity of the mineral waters depends on how much carbonic acid they contain; pH typically ranges from 5.5 to 6.5. The mineral springs discharge cold water (Sneeringer and Dunn. 1981).
The distribution of the wells, a total of about 200, is controlled by the MacGregor Fault and its subsidiary faults. The mineral waters always occur on the eastern (downthrown side) of the fault.
Puzzling is the observation that the precipitate is calcite rather than aragonite. Travertine in other places is usually calcite, but the composition of the responsible mineral waters shows depletion in magnesium. By contrast the mineral waters of Saratoga are enriched in magnesium and because the magnesium ion inhibits the formation of calcite, aragonite should result, but apparently does not. This question deserves study.

Domed Cyanobacterial Cabbage Heads: (Stromatolites).
This locality is the site of one of the finest domed microbial mats to be seen anywhere preserved in ancient rocks. On the east side of the road in Lester Park a glaciated surface exposes horizontal sections of the cabbage-shaped heads composed of vertically stacked, hemispherical algal layers (Fig. 4). These structures, known as Cryptozoons, have been classically described by James Hall (1847, 1883), Cushing and Ruedemann (1914), and Goldring (1938); an even earlier study drew attention to the presence of ooids as the first reported ooid occurrence in North America (Steele,1825). Interest in these rocks has been revived as they are useful environmental indicators (Logan, 1961; Fisher, 1965, Halley, 1971). The heads are composed of discrete club-shaped or columnar structures built of hemispheroidal microbial mats expanding upward from a base, although continued expansion may result in the fusion of neighboring colonies into a Collenia-type structure (Logan, Rezak and Ginsburg, 1964). The stromatolites are part of the Hoyt Limestone of Late Cambrian (Trempealeauan) age. Their intertidal origin has been inferred by (1) observations in the rocks, and (2) by analogy with similar modern microbial heads.
The evidence for deposition under tidal conditions for the Hoyt Limestone at Lester Park includes: (1) mud cracks, (2) flat-pebble conglomerate, (3) small channels, (4) cross-beds, (5) bird's eye structures, (6) syngenetic dolomite, and (7) stromatolites (for criteria on recognition of tidal limestones, see Friedman, et al., 1993). The analogy with modern environments relates to the occurrence of cabbage-shaped microbial heads in the intertidal zone of Shark Bay, western Australia, in which the height of the domes is controlled by the degree of turbulence (Logan, Rezak and Ginsburg, 1964; Hoffman, Logan and Gebelein, 1969). With increasing wave and current energy the height of the domes increases; the relief of the domes decreases landward towards quieter water conditions.
At Lester Park the heads which are circular in horizontal section range in diameter from one inch to three feet; many are compound heads. The size of the larger heads suggests that they formed in highly turbulent waters.
The line of depositional strike along which the domed microbial mats occur was probably where the waves were breaking as they came across the deeper ocean from the east and impinged on the shallow shelf.
Several petrographic observations in these rocks permit an analogy with modern microbial mats in hypersaline pools of the Red Sea Coast (Friedman and others, 1972; Friedman and others, 1985). Mat-forming cyanobacteria secrete radial ooids, oncolites, and grapestones which occur in these rocks; interlaminated calcite and dolomite which in part compose the stromatolites of the Hoyt Limestone correspond to alternating aragonite and high-magnesian calcite laminites which modern blue-green cyanobacteria secrete. In modern microbial mats the high-magnesian calcite laminites contain abundant organic matter in which magnesium has been concentrated to form a magnesium-organic complex. Between the magnesium concentration of the high-magnesian calcite and that of the organic matter sufficient magnesium exists in modern microbial laminites to form dolomite. Hence the observation in ancient stromatolites, such as observed in the Hoyt Limestone, that calcite and dolomite are interlaminated, with calcite probably forming at the expense of aragonite and dolomite forming from high-magnesian calcite.
Note ooids, skeletal fragments, and coarse quartz particles dispersed between the microbial heads.
The dominant microbial process active in the deposition of the Hoyt Formation appears to have been binding, as microbial boundstones comprise most of the beds observed in the outcrop. There is, however, an abundance of forms in the Hoyt Formation. Logan (1961) and Logan et al. (1964) have shown that morphologic variations in microbial mats are largely related to the amount of energy or turbulence of the depositional environment. The Hoyt lithologies indicate a wide range of energy conditions.
The Hoyt Formation shows only minor evidence of the destruction (or bioturbation) of microbial mats by organisms. Evidence of both microbial binding and precipitation of calcium carbonate is present in the Hoyt Formation, with binding the dominant process during deposition.
The lower part of the Lester Park section on the west side of the road provides the most complete sequence observed in the Hoyt Formation. A vertical sequence from Lithofacies 1 to Lithofacies 4 (Fig. 5) is represented. Depositional environments ranging from the lee of an oolite shoal upward to the lower intertidal zone are shown in the lower Lester Park section. The sequence seen here may have resulted from the lowering of sea level (regression) or from the depositional buildup of carbonates (progradation).
The ooids at Lester Park were the first to have been described from North America (Steele, 1825).
Figure 6 presents a cross-section of the hypothesized Hoyt depositional model. The following observations support the model: 1) the presence of well-developed ooids in the Hoyt lithologies suggests that the offshore energy barrier was an oolite shoal perhaps similar to that of the western Bahama Bank (Ball, 1967) or to that of Abu Dhabi on the Trucial coast (Kendall and Skipwith, 1969; Friedman 1995); 2) the presence in the Hoyt of reef-like development of high-relief columnar stromatolites immediately overlying cross-bedded oolite, and the dependence of stromatolite morphology on energy (Logan et al., 1964), suggest that the large microbial heads were restricted to high-energy areas surrounding tidal washover deltas; 3) the presence of coarse calcarenite infilling the heads. Storm surges may account for mixing of carbonate grains in the different lithofacies.
Students should prepare a map of the planed, glaciated surface beneath which the domed microbial mats are exposed. An ecologic zonation may be observed based on the density of microbial heads. This distribution should be shown on the map. Sketches should be prepared of the different kinds of heads: single and compound heads, large heads vs. small heads. Is it possible from this map to determine the depositional strike of the original geologic setting? Note the kinds of particles occurring between the heads. Lie flat on your belly and use a hand lens to advantage. Note the coarse quartz particles scattered among the carbonate particles.
The vertical section on the west side of the road reveals a ledge of ooids. Examine but do not destroy this ledge. Remember, as this article points out, you are treading on hallowed ground. These oolites were the first to have been described from North America, back in 1825.

Quartz-cobble conglomerate
Pass basal Paleozoic quartz-cobble conglomerate (a possible talus deposit) on weathered Pre-Cambrian gneiss 1/2 mi. east of Cymbal's Comers (NY 147).

STOP 3. Fort Hunter Quarry
Alight at slight bend in road and walk to Fort Hunter Quarry which is across a former railroad track (now a bicycle pass) close to Mohawk River. (Fort Hunter Quarry cannot be seen from road; another small quarry visible from road is approximately 0.1 mile farther east, but will not be visited on this trip).
Products of Tidal Environment: Stromatolites
Stromatolites in the Fort Hunter quarry consist almost entirely of dolomite in the form of irregularly bedded, finely laminated, undulating structures. The rocks in this quarry are part of the Tribes Hill Formation of earliest Ordovician (Fisher, 1954). The lithofacies of the Tribes Hill Formation have been studied in detail by Braun and Friedman (1969) within the stratigraphic framework established by Fisher (1954). Figure 8 is a columnar section showing the relationship of ten lithofacies to four members of the Tribes Hill Formation. At Fort Hunter we will study the lowermost two lithofacies of the Fort Johnson Member (see column at right (east) end of section. in fig. 8.
Two lithofacies are observed: (1) lithofacies 1, mottled feldspathic dolomite, and (2) lithofacies 2, laminated feldspathic dolomite. Lithofacies 1 is at the bottom of the quarry, and lithofacies 2 is approximately half way up.
This facies occurs as thin dolostone beds, 2 cm to 25 cm but locally more than 50 cm thick, with a few thin interbeds of black argillaceous dolostone which are up to 5 cm thick. In the field, the dolomite shows gray-black mottling and in places bird's eye structures. In one sample, the infilling of the bird's eyes shows a black bituminous rim which may be anthraxolite. In the field, trace fossils are abundant, but fossils were not noted. Authigenic alkali feldspar (microcline) is ubiquitous throughout this lithofacies. The insoluble residue makes up 22 to 54% by weight of the sediment in samples studied with most of the residue composed of authigenic feldspar.
This lithofacies is mineralogically identical to the previous facies but differs from it texturally and structurally in being irregularly bedded and in containing abundant undulating stromatolitic structures ("pseudo-ripples") (fig. 9) as well as disturbed and discontinuous laminae. In places there are a few thin interbeds of black argillaceous dolostone. The thickness of the laminites of this facies ranges from 1/2 mm to 2 or 3 mm; on freshly broken surfaces the color of the thinner laminae is black and that of the thicker ones is gray. The insoluble residue, for the most part composed of authigenic feldspar, constitutes between 35% and 67% by weight in samples studied. These two lithofacies which form the basal unit of the Ordovician, were formed on a broad shallow shelf.
Stromatolites, bird's eye structures, scarcity of fossils, bituminous material, syngenetic dolomite, and mottling suggest that these rocks were deposited in a peritidal environment (Friedman, et al1992). Based on analogy with the carbonate sediments in the modem Bahamas, Braun and Friedman (1969) concluded that these two lithofacies formed under supratidal conditions. However in the Persian Gulf flat microbial mats prefer the uppermost intertidal environment, and along the Red Sea coast they flourish where entirely immersed in seawater, provided hypersaline conditions keep away burrowers and grazers (Friedman and others, 1973). Hence on this field trip we may conclude that the stromatolites indicate peritidal conditions without distinguishing between intertidal and supratidal. For more details on these lithofacies refer to Braun and Friedman (1969).
Data obtained from the analyses of fluid inclusions in calcite-healed fractures of these Lower Ordovician carbonate strata, in which microcline crystals are so prominent, indicate higher paleotemperatures and greater depth of burial than have previously been inferred for the rocks of this region (Urschel and Friedman 1984; Friedman 1987a,b). Average fluid- homogenization temperatures range from 96° C to 159° C . These high paleotemperatures are supported by oxygen-isotope and conodont-alteration data (Harris et al. 1978). A former depth of burial > 7 km is implied when a geothermal gradient of 26° C/km (Friedman and Sanders 1982; 1983) is used.
The study of the authigenic alkali feldspar from this quarry yielded an age of uplift of approximately 320 Ma (Friedman 1990), Carboniferous in age. The observation that authigenic feldspar in Cambro-Ordovician carbonates occurs along the proto-Atlantic shelf from the Appalachian Basin to Newfoundland, Scotland, and Greenland paralleling the Taconic belt suggests active crustal epeirogeny in Pennsylvanian-Permian time.
Thus, following subsidence to great depth, Pennsylvanian to Permian epeirogeny uplifted the strata, resulting in deep erosion. This leads to the surprising conclusion that isostatic unroofing following uplift has stripped off thick sections of strata whose presence was previously unsuspected.

Cross original Erie Canal, built in 1822.
Amos Eaton surveyed this route at the request of Stephen Van Rensselaer (1764-1839); after this survey Amos Eaton (1776-1842) and Van Rensselaer decided to found a school for surveying,

STOP 4. North Tribes Hill Quarry
Take the trail towards old abandoned crusher, but instead of heading towards the quarry move uphill to the first rock exposures. The rocks to be examined are near the edge of steep cliff.
Description and Discussion
At this stop microbial reef mounds are exposed (Friedman, 1996). Ordovician domal thrombolites, termed here microbial reef mounds, occupied the basal part of meter-scale shallowing-upward cycles (Fig. 10). They are part of a high-energy facies that a sharp transgressive surface separates from an underlying low-energy peritidal setting. This erosional surface served as the surface on which one of the reef mounds established itself during initial transgression before further deepening. The others overlie a floor of skeletal grainstone reflecting a high-stand sea-level facies tract. Skeletal grainstone composes the fill between the mounds. A channel and several aggrading hummocks occupy inter-reef mound areas resulting from storm events in a subtidal setting.
Reef mounds formed at or near the base of upward-shallowing parasequences. They are part of a high-energy facies which a parasequence surface of emergence or near emergence separates from an underlying parasequence which terminated a low-energy peritidal setting. This erosional surface between the two parasequences is interpreted as a partly lithified hard ground. As elsewhere in the Cambro-Ordovician of North America, microbial reef mounds commonly occur near the bases of upward-shallowing cycles and most rest directly on underlying cycle caps (Osleger and Montanez 1996).
Mound-Foundation Facies
Braun and Friedman (1969) designated the facies underlying the reef mounds as Lithofacies 7: Mottled Dolomitic Micrite and Biomicrite of the Wolf Hollow member (Fig. 8). This lithofacies is made up of a well-bedded, mottled limestone in which the mottles are composed of irregular patches of dolomite. On weathered surfaces, the limestone is whitish and the dolomite buff, but on freshly broken surfaces both limestone and dolomite are very light gray with the limestone somewhat darker and the dolomite of granular appearance. The outlines of large gastropods and cephalopods stand out, in places, on weathered bedding planes. A list of fossils found in this lithofacies was given by Fisher (1954, p. 88-89). Bird's eye structures are present in some beds as are pyrite patches. The limestone contains abundant dolomite-filled burrows, most of which are horizontal (or sub-horizontal) to the bedding plane, but some burrows have oblique to perpendicular orientations with respect to bedding. Many gastropods, especially Ophileta and Ecculiomphalous are found with the dolomite-filled burrows suggesting that these burrows may have been made by gastropods rather than by worms. However, the morphology of the shells suggests that these gastropods were not burrowers. Hence, worms or other soft-bodied organisms must have been abundant and produced the burrows.
This facies which is part of the Wolf Hollow Member (see Fig. 8), represents a low-energy deposit of micrite of a shallowing-upward cycle terminating in a sharp, planar erosion surface. This erosional parasequence surface is a marine flooding surface and represents a transgressive event for the next high-energy cycle in which the reef mounds formed. Below one of the reef mounds the underlying micrite of mound-foundation facies compacted (Fig. 11).
Differential compaction of this former lime mud, as the solid reef grew, suggests that the lime mud had not yet fully lithified (Friedman 1996). This observation differs somewhat from that of reef mounds in Virginia and Argentina where a solid hard ground served as foundation for the reef mounds (Read and Grover 1977; Canas and Carrera 1993). However, the original lime mud of the mound-foundation facies of the Tribes Hill mounds was sufficiently lithified to support the growing mounds (Friedman 1996).
Microbial Reef-Mound Facies
Reef mounds are prominent in the Wolf Hollow Member of the Tribes Hill Formation (Figs. 10,11). They occur as isolated mounds (Friedman 1996). These mounds are approximately one meter in length (measurements vary from 95 cm to 135 cm) and 60 to 70 cm in thickness. These measurements are approximate dimensions because the mounds do not stand out freely, and disappear in the enveloping facies. Moreover in the exposure, it is difficult to differentiate between short and long axes of the mounds.
The reef mounds are composed of clotted and peloidal microcrystalline matrix which was microbially precipitated. comparable to that in modern reefs (Friedman et al. 1974). In modern reef settings, peloids display the pattern of calcified coccoid cells which cyanobacteria or chemo-organo-trophic bacteria degrading the cyanobacterial organic matter precipitate (Friedman et al. 1985; Krumbein 1983). These textural features are products precipitated by the micro-environment of cyanobacteria (Nadson 1903; Kalkowsky 1908; Pia 1927; Johnson 1954; Endo 1961; Friedman et al. 1973). Peloids have been described as calcified algal filaments (Friedman et al. 1974); such calcification may be the result of precipitation of calcium carbonate on cyano-bacterial filaments in the presence of live bacteria (Chafetz and Buczynski 1992).
Because they are composed of microcrystalline carbonate matrix, the microbial reef mounds have a texture similar to that of the mound-foundation facies lithofacies 7 (see Fig. 8), a micrite. The term matrix has been commonly misapplied as a synonym of micrite, but the mounds are not composed of micrite. Mechanically deposited lime mud, following lithification, is known as micrite (Folk 1959). Identifying even modern reef rock is an experience in frustration: submarine microcrystalline or cryptocrystalline matrix that is biologically precipitated within millimeters to centimeters of the surfaces of reef rock is identical in appearance to micrite of mechanical origin. Case histories abound in which unwary geologists have misidentified the reef rock for low-energy facies composed of micrite (Friedman 1985, 1994). Since micrite of low-energy origin and microcrystalline or cryptocrystalline matrix of reefs are indistinguishable it is easy to confuse high-energy reef facies for low-energy lime- mud facies (Friedman 1985, 1994). This textural similarity led initially to an interpretation that mounds may be blocks of lithofacies 7 (micrite and biomicrite) that foundered and became lodged in channels (Braun and Friedman 1969). These reef mounds resemble blocks of micrite in tidal channels of the Bahamas that are derived by undercutting of the banks of the channels (Braun and Friedman 1969).
The reef mounds were included with lithofacies 8 of Braun and Friedman (1969) designated intrasparite and biosparite; the lithology is for the most part a skeletal grainstone. This lithofacies was referred to as channel fill, comparable to the Lower Ordovician reef mounds of western Argentina, of which Cafias and Carrera (1993, p. 169) noted "the reef mounds are dissected by conspicuous channels filled with coarse crinoidal grainstone and litho clastic rudstone" (Fig. 11). This same observation applies in part to the setting of the Tribes Hill Formation. As in western Argentina, the reef mounds of the Tribes Hill Formation formed in part on a previously lithified or partly lithified sediment surface (Cafias and Carrera 1993, p. 169); and as in other places in North America, they occur near the base of an upward-shallowing cycle. The surface on which one of the mounds developed is a sharp transgressive parasequence surface separating the underlying peritidal lithofacies 7 (micrite and biomicrite) from the overlying subtidal reef-mound facies. The other reef mounds nucleated near the transgressive parasequence surface, but on top of underlying skeletal grainstone, during the initial transgression before rapid deepening occurred, a setting which is similar to that of comparable facies in the Great Basin, U.S.A. (Osleger and Montanez 1996).
Inter-Reef Mound Facies
Skeletal grainstone composes the fill between the reef mounds. One channel and several hummocks occupy the inter-reef mound areas (Fig. 12). The top of one of the hummocks rolls into the channel fIll. The grainstones form lenses that build on top of one another. The channel displays the typical asymmetric profile of a tidal channel with a steep cut-bank and a low-angle slip-off slope (Fig. 12). However, the channel is entirely within grainstone, hence it is not a normal tidal channel which would be fine-grained on the steep side and coarse-grained on the opposing side. In normal tidal channels, as the channel shifts it leaves behind a layer of coarse debris at the bottom of the channel (Friedman, et al. 1992). No such channel-floor lag layer is present in the inter-reef mound facies. Hence the channel must be related to storm deposition of the grainstone since filling is not the result of the shifting of the channel. Truncation by the channel and aggradation of the hummocks occurred at the same time. The channel and hummocks formed as a result of storm events in a subtidal setting. Following transgression, storm tides and currents generated this channel between which reef mounds and inter-reef mound facies accumulated. This channel, which was incised down to 30 cm into the underlying grainstone, is conspicuous and displays sharp margins (Fig. 12).
Of the various reef mounds one rests directly on the mound-foundation surface; grainstone of inter-reef mound facies makes up the floor of all the others.
The reef mounds formed in shallow-subtidal to possibly low intertidal settings in an agitated environment devoid of lime mud.
This stop was very difficult to locate. We are told "Going east on Route 67, after the intersection with Route 147, five roadcuts on either side of Route 67 expose outcrops of the Lower Ordovician Gailor Formation." However, if we are east of 147 we are no longer in the Lower Ordovician. Furthermore, stop 8 is said to be near Waite Road, and stop 9, presumably further east, is at Manny's Corners. Yet Manny's Corners is definitely west of the intersection of 67 and Waite Road. My conclusion is that the author had confused field trips, and these stops were from a trip in which participants went clockwise, instead of counterclockwise, around the loop. Hence I locate stop 5 just west of the intersection with 147, and move to the west from there. Since the author gave no guidance on mileage, I guess on locations - a lot!

STOP 5. Exposures of Gailor Formation
On the north and south sides of the road are exposed a massive dolostone unit overlain by a bedded dolostone unit. Roughly 10' of section are exposed here. The massive unit is dark gray in color while the upper bedded unit is lighter gray and coarser as well. Large clasts in a variety of shapes and sizes, composed of micrite and medium-textured dolostones are scattered all over the outcrop and concentrated in the basal massive unit. Pods and lenses of chert colored black and white are profuse. Calcite mineralization is also a common feature, occurring in patches and veins in orange, white and black. Stromatolites are observed in the section on the north side of the road.
The breccia observed in the section perhaps represents dissolution collapse. The massive unit in the lower part of the section may be a microbial build up. The stromatolites suggest a peritidal origin for these dolostones.
This stop was very difficult to locate. We are told "Going east on Route 67, after the intersection with Route 147, five roadcuts on either side of Route 67 expose outcrops of the Lower Ordovician Gailor Formation." However, if we are east of 147 we are no longer in the Lower Ordovician. Furthermore, one stop is said to be near Waite Road, and the next stop, presumably further east, is at Manny's Corners. Yet Manny's Corners is definitely west of the intersection of 67 and Waite Road. My conclusion is that the author had confused field trips, and these stops were from a trip in which participants went clockwise, instead of counterclockwise, around the loop. This is the first roadcut I could find west of the intersection with 147.

Farther east on the north and south side of 67 are exposed roughly 27' of section. The following features are observed:
-wavy beds,
-massive units alternating with bedded dolostone units,
-the massive units appear to have a lenticular mound-like form, perhaps representing former microbial buildups,
-the beds overlying the mounds display dips on flanks of the mounds perhaps indication fore-reef slopes,
-pervasive dolomitization seems to have obliterated original depositional features,
-alternatively the wavy bedding may represent tidal channels or hummocky cross stratification,
-other features observed in these units are fine laminae in the dolostones, burrow mottling, stylolites, presence of pyrite and white calcite mineralization in vugs and fractures.
This stop was very difficult to locate. We are told "Going east on Route 67, after the intersection with Route 147, five roadcuts on either side of Route 67 expose outcrops of the Lower Ordovician Gailor Formation." However, if we are east of 147 we are no longer in the Lower Ordovician. Furthermore, one stop is said to be near Waite Road, and the next stop, presumably further east, is at Manny's Corners. Yet Manny's Corners is definitely west of the intersection of 67 and Waite Road. My conclusion is that the author had confused field trips, and these stops were from a trip in which participants went clockwise, instead of counterclockwise, around the loop. Although there is another outcrop to the west of Stop 5, it is small, and only on the south side of the road. This is one looks 27' tall and is on both sides of the road.

Farther east are exposed roughly 15' of bedded dolostones displaying planar stromatolites, intraclasts, and bird's eye structures indicating peritidal environments of deposition.
This stop was very difficult to locate. We are told "Going east on Route 67, after the intersection with Route 147, five roadcuts on either side of Route 67 expose outcrops of the Lower Ordovician Gailor Formation." However, if we are east of 147 we are no longer in the Lower Ordovician. Furthermore, one stop is said to be near Waite Road, and the next stop, presumably further east, is at Manny's Corners. Yet Manny's Corners is definitely west of the intersection of 67 and Waite Road. My conclusion is that the author had confused field trips, and these stops were from a trip in which participants went clockwise, instead of counterclockwise, around the loop. The author gives no mileage guidance

STOP 8. Small section on the north side of 67
This is a small section on the north side of 67 near Waite Road. The section displays intraclasts and stromatolites.

Farther east on Route 67 near Manny Corners is a section exposing roughly 26' of bedded dolostones. The following features are observed here:
- planar and domal stromatolites,
- intraclasts ranging in size from 1 to 2 inches,
- vugs and fractures partially or completely filed with black and white calcite,
- bird's eye structures,
-bedded and nodular chert,
-breccia representing dissolution collapse?
The above mentioned features displayed in these fine- to medium-textured dolostones point to a peritidal environment of deposition.
This stop was very difficult to locate. We are told "Going east on Route 67, after the intersection with Route 147, five roadcuts on either side of Route 67 expose outcrops of the Lower Ordovician Gailor Formation." However, if we are east of 147 we are no longer in the Lower Ordovician. Furthermore, one stop is said to be near Waite Road, and the next stop, presumably further east, is at Manny's Corners. Yet Manny's Corners is definitely west of the intersection of 67 and Waite Road. My conclusion is that the author had confused field trips, and these stops were from a trip in which participants went clockwise, instead of counterclockwise, around the loop. The author gives no mileage guidance. This outcrop is close to Manny's Corners, but it doesn't look like 26' of section...

A6: GEOLOGIC FIELD GUIDE TO THE BALMAT ZINC MINE, ST. LAWRENCE COUNTY, NY
W.F. deLorraine and J. Johnson
Mining Division
Zinc Corporation of America Mines, Inc.
Balmat, NY 13609
Introduction and Geologic Setting
Orebodies of the Balmat-Edwards-Pierrepont Zinc mining district in the Northwest Adirondacks of New York State rank as world-class deposits with over 45 million tons of past production plus total reserves. Orebodies occur in "clean" Proterozoic siliceous dolomitic marble that was metamorphosed and poly-deformed during the Grenvillian Orogeny about 1.1 billion years ago. The NW Adirondack Lowlands are underlain by metasedimentary rocks, predominantly marble, calc-silicate and subordinate paragneiss and metavolcanic rocks. The Adirondack Highlands to the east are predominantly underlain by anorthosite-mangerite-charnockite- granite suite (AMCG) rocks metamorphosed to granulite facies. The two provinces are separated by the Carthage-Colton line or "Highlands-Lowlands" boundary, a narrow northeasterly-trending, northwest-dipping zone of mylonitization separating the upper amphibolite-facies Lowlands from the granulite-facies Highlands to the east. Flat-lying lower Paleozoic rocks surround and unconformably overlie the crystalline rocks of the Adirondack dome.

Zinc Mine
The presently known zinc orebodies of the Balmat mine lie within one mile of the central No.4 shaft, in an area of approximately two square miles. A majority of the ore shoots are arranged in clusters customarily known as the Balmat No.2, 3, and 4 mines, after the shafts which service them. In this guide, the ore clusters will be described as belonging to No.2, 3, and 4 mines, although these are more properly interconnected mining units now centralized around No.4 shaft, from which Balmat ore is hoisted to the adjacent mill (Fig. 15).

A7: GEOLOGY, LIMNOLOGY AND PALEOCLIMATOLOGY OF GREEN LAKES STATE PARK, NY
Martin F. Hilfinger IV and Henry T. Mullins
Heroy Geology Laboratory
Syracuse, New York 13244
Green Lakes State Park, located ~15 km east of Syracuse, New York near the village of Fayetteville, is a stunning geologic and limnologic wonderland (Fig. 1). Located along the axis of a narrow glacial meltwater channel, the Park consists of two small, moderately deep (maximum water depth of ~53 m) lake basins (Green Lake and Round Lake), protected along their flanks by steep walls of Silurian bedrock and separated from each other by a small modern wetland (Figs. 2 and 3).
These lakes are unusual, not only for their geologic setting, but also their water characteristics which have attracted the attention of limnologists for decades. In fact, limnologically, Green Lake is one of the best studied lakes in the world (Torgersen et al., 1981; Thompson et al., 1990). There are two aspects of the limnology of Green Lake which make it so interesting. Foremost is the fact that it is a meromictic lake (as is Round Lake) which means that when the water column turns over seasonally, it does so only above a strong chemically-controlled density boundary or chemocline at a water depth of ~18 m (Fig. 4). Because of this, bottom waters >18 m deep are permanently stratified and devoid of oxygen (anoxic). The second unusual limnologic feature of these lakes is that they annually precipitate large amounts of calcium carbonate (calcite), both from the open, wind-mixed surface waters of the lake (epilimnion) and along their shallow, near shore (littoral zone) margins in the form of "reefs" or bioherms.
The annual precipitation of calcite from the epilimnion coupled with the fact that deep bottom waters are anoxic, results in the deposition and preservation (no bioturbation) of annual sediment laminations or true varves. Because of this, Green Lake and Round Lakes have enormous potential from unraveling decadal to annual scale climate change (paleoclimatology) for at least the entire Holocene (past 10,000 years). With our current interest and concerns about possible global warming, the meromictic lakes of Green Lakes State Park may well provide a longterm, high-resolution template of natural climatic variability in which to view future environmental change. The purpose of this field trip is to acquaint you with the basic geology, limnology, and preliminary paleoclimatology of Green Lakes State Park. We will draw upon an extensive published literature to discuss: (1) the geologic origin of the lakes; (2) their fundamental limnology; (3) the annual, open water precipitation of calcium carbonate which will explain why "Green Lake is green"; and, (4) the origin of their "fringing reefs"; we will then draw upon new, unpublished data that will: (5) document the natural history of relative lake level fluctuations, and thus climate change, throughout the Holocene; and finally, (6) examine in high resolution, the natural and anthropogenic environmental changes which have occurred over the past 2,500 years.
This fieldtrip will be a leisurely half-day walking tour around both Green and Round Lakes. Scientific information will be provided via a series of large, colorful posters supplemented by on site examination of sediment cores. There will be ample time for discussion, and if the weather cooperates, we will be treated to a spectacular feast of fall foliage against the backdrop of aqua lakes; so, bring an open mind and your cameras!

A7: Geology, Limnology and Paleoclimatology of Green Lakes State Park, New York

STOP 1. Geologic Setting and Origin of the Lakes
Our discussion of the geology of Green Lakes State Park will take place on the swimming beach at the north end of Green Lake. From here we will have an unobstructed view to the south along the axis of the glacial meltwater channel in which Green and Round Lakes reside.
As we look to the south, steep bedrock walls can be seen rising from the surface of Green Lake at an elevation of 418 ft. (127 m) to at least 550 ft. (168 m) above sea level, although the highest summit (South Hill) adjacent to the park extends to an elevation of 788 ft. (240 m) (Fig. 2)(Muller, 1967). Total bedrock relief in the area, as measured from the top of South Hill to the bottom of Green Lake is 543 ft. (166 m). However this value should be considered a minimum because the thickness of sediments beneath the floor of Green Lake is not known, although Muller (1967) reported that drilling "just north" of Green Lake penetrated 138 ft. (42 m) of unconsolidated sediment without reaching bedrock.
The rocks that make up the walls of the meltwater channel in Green Lakes State Park are part of the Salina Group of Silurian (∼440 to 410 million years ago) age (Muller, 1967). The oldest stratigraphic unit in the Park is the Vernon Shale which consists largely of easily eroded red and green shale as well as gypsum (CaSO4·H2O). The top of the Vernon Shale extends upward to within ∼40 ft. (12 m) of the surface of Green Lake (Fig. 4; Muller, 1967). Overlying the Vernon Shale is more shale and argillaceous dolostone of the Syracuse Formation which contains evidence ("hopper casts") of evaporite minerals such as halite (NaCl) and gypsum. This middle unit extends upward to about the present day surface elevation of Green Lake (Fig. 4). The remainder of Silurian stratigraphy here consists of a relatively resistant dolostone member of the Syracuse Formation (Fig. 4) and the overlying Camillus Shale capped by a dolostone of the Bertie Formation which forms the summits of surrounding hills (Muller, 1967). The lake basins, however, rest within shales and evaporites of the Syracuse Formation and underlying Vernon Shale (Fig. 4).
Both Green Lake and Round Lake are located in an east-northeast "cross channel" (Fairchild, 1909; Sissons, 1960) which cuts obliquely across the Onondaga Escarpment at the northern edge of the Appalachian Plateau (Fig. 1 and 2). Today, this cross channel is drained by a "markedly underfit stream" (Muller, 1967) and near its southwestern end there is an abrupt topographic drop of ∼100 ft. (30.5 m) from a dolostone member of the Syracuse Formation to the surface of Round Lake (Fig. 2).
As noted by Muller (1967), Green Lake (which was originally known as Lake Sodom) was first depth sounded by Vanuxem (1839) and subsequently by Miner (1933), who also sounded (via lead-line) Round Lake. Both lakes consist of steep-sided, flat-floored, semi-circular basins with maximum water depths slightly >50 m. However, Green Lake also contains an elongated "neck" or "handle" which shoals to the north (Fig. 2). As also noted by Muller (1967), the surface elevations of Green Lake (418 ft; 127 m) and Round Lake (421 ft.; 128 m) are significantly (∼6 m) below the highest stand of pro-glacial Lake Iroquois which existed from ∼12.5 to 11.4 ka 14C (Muller and Prest, 1985; Anderson and Lewis, 1985). The surface of Green Lake is also ∼6 ft. (2 m) lower in elevation then the water surface of the nearby Erie Canal (Fig. 2).
Green Lakes State Park is located north of the Valley Heads Moraine which was deposited ∼14.4 ka 14C (Muller and Calkin, 1993) during a brief phase of Laurentide ice sheet instability coincident with Heinrich event H-l (Mullins et al., 1996). Thus, modern Green Lake and Round Lake must be less than 14,400 14C years in age (Fig. 5). The meltwater channel in which both lakes reside connects in the village of Fayetteville with Pompey Hollow, a large glacial trough whose origin is likely linked with the nearby Finger Lakes (Mullins et al., 1996). The Green Lakes meltwater channel is but one of many east-west orientated glacial drainages in the Syracuse-Oneida region (Sissons, 1960). The origin of the Green Lake and Round Lake basins is still uncertain although a number of hypotheses have been proposed (Muller, 1967), including: (1) plunge-pools; (2) solution sinkholes; and, (3) subglacial meltwater "potholes". Native American legend of "Kayahao" originally suggested that the lakes were volcanic in origin although there is no evidence to support it. This legend speaks of a Native American woman who infuriated the spirit of the lake which then " ... spit forth fire and flame, (and) caused a great commotion of the waters ... " (Gibson, 1925, p. 21).
The most widely accepted hypothesis is that these lake basins were scoured out at the base of large, late-glacial waterfalls. Based on stratigraphic relationships and morphology, Miner (1933) developed the hypothesis that the lakes are glacial plunge-pool basins (Fig. 6) which followed Vanuxem's (1839) earlier suggestion that they were eroded by a "whirlpool of great magnitude". However, problems with this hypothesis have centered around the source of water for the waterfalls plus the fact that there are two ("twin") lake basins.
Fairchild (1899) suggested that water impounded in high-standing proglacial lakes to the south of the Park may have cut the Green Lakes meltwater channel, whereas Sissons (1960) argued that water flowed from the Great Lakes in a complex system of marginal, subglacial and englacial conduits. If Fairchild's (1899) view of a proglacial source of water is correct, then Pompey Hollow, which connects with the Green Lakes meltwater channel at an elevation of ∼530 ft. (162 m), is a likely source. Pompey Hollow, a 1 km wide, flat-floored (∼780 ft., 238 m) trough, with as much as 520 ft. (159 m) of relief, extends south of the Park for ∼20 km (Fig. 1). As ice receded from the Valley Heads Moraine at Delphi Falls shortly after 14.4 ka 14C proglacial lake waters would likely have been impounded in Pompey Hollow, dammed by the Valley Heads Moraine to the south and the Laurentide ice sheet to the north (Fig. 5). In the nearby Finger Lakes, high-standing proglacial lakes existed until -13.9 ka 14C when the ice sheet retreated north of the Onondaga Escarpment opening up lower elevation outlets to the east which resulted in catastrophic drops of proglacial lake levels, cutting of gorges (glens), and a drainage reversal (Mullins et al., 1996). Muller (1967) has argued that the Green Lakes Channel originated as a pre-late Wisconsin feature. If correct, then as the northward retreating Laurentide Ice Sheet uncovered the precursor Green Lakes Channel impounded proglacial lake waters in Pompey Hollow (hundreds of feet higher in elevation) may have catastrophically poured through the Green Lakes meltwater channel (Fig. 5). Today, unlike the Finger Lakes, Pompey Hollow is a dry, flat-floored lake valley.
Such a scenario may have been similar to that documented for the Syracuse meltwater channels which experienced catastrophic floods with waterfalls the size of Niagara Falls when a 600 ft. (183 m) deep proglacial lake in the Onondaga-Tully trough drained to the east (Hand and Muller, 1972; Hand, 1978) creating a plunge-pool basin at Clark Reservation. Hand (1978) estimated that such catastrophic floods may have had water discharge as high as 7,000,000 ft.3/sec. (∼2.1x106 m3/sec.) and flow velocities exceeding 50 ft/sec. (∼15 m/sec.)! Similar catastrophic floods from Pompey Hollow, flowing over relatively resistant dolostone caprock as a waterfall in Green Lakes Channel may have eroded underlying shales to produce plunge pool basins which today we know as Green and Round Lakes.
The second problem which must be overcome for the plunge pool hypothesis to be viable, is the origin of "twin basins" which has previously been discussed by Muller (1967). Because simple headward erosion of a waterfall should result in a single gorge, Fairchild (1909) proposed a simple solution; that the Green and Round Lake basins do occupy a single bedrock trough but have been isolated by post-glacial sediment accumulation (Fig. 6). If correct, then the depth to bedrock beneath the wetland between Green and Round Lakes should be similar to that beneath the basins (i.e. >50 m). However, we have collected sediment cores only up to 11 m in length from this wetland (see Stop #4) which represent ∼9,100 14C years. Also, one of our cores from the center of the wetland penetrated only 4.8 m and appeared to bottom on bedrock. Thus, there may be a bedrock high or sill separating Green and Round Lakes. A land-based seismic reflection/refraction profile along the axis of this wetland would likely resolve the question of whether or not the lakes are separated by a bedrock sill.
A second possibility is that the lake basins formed sequentially, with Green Lake having formed first. This would necessitate a phase of rapid waterfall retreat to form the elongated "neck" of Green Lake followed by a pause in the rate of retreat to form the main basin of Green Lake. A second phase of rapid waterfall retreat would then be required followed by a second pause to excavate the Round Lake basin. Such a scenario could be reconciled if the outpouring of pro glacial lake waters from Pompey Hollow occurred in the two discrete phases, perhaps as a result of glacial oscillation (Muller, 1967).
A third hypothesis, advocated by Muller, 1967), is that there were twin waterfalls which migrated headward simultaneously. For this mechanism to work there must have been some stratigraphic (or structural) control to initiate twin falls during a single meltwater episode. Muller (1967) suggests that both basins were controlled by water falling over dolostone caprocks; Green Lake basin by the "Middle Dolomite" of the Syracuse Formation and Round Lake basin by the "Upper Dolomite". The fact that there is no headwall scarp at the southwest end of Green Lake (as there is at Round Lake) would have to be explained by either incision and erosion of the lower caprock or by "burial" of the scarp by subsequent impounding of waters in Green Lake (Muller, 1967).
It is apparent from the above discussion that the origin of Green and Round Lakes continues to be uncertain. However, morphologically, they do appear to be plunge-pool basins but satisfactory explanations for the source of the water and why there are "twin basins" must be acceptable. Most useful would be the acquisition of subsurface data, both geophysical and drill core.

STOP 2. Limnologic Setting of Green Lake
From our vantage point at Stop 1 we will progress clockwise and walk a few hundred meters along the lake path to an open area just south of the diving platform. Here we will continue to have an open view of Green Lake and have an opportunity to present and discuss it's basic limnology (characteristics of the water column). Limnologically Green Lake is probably the best studied meromictic lakes in the world (Thompson et al., 1990); thus, there are considerable data from which to draw upon.
According to Thompson et al. (1990), Clark (1849) was the first to report (quoting L.C. Beck) that there was something unusual about the limnology of Green Lake: "Water drawn from a depth of one hundred and sixty-eight feet (51 m) was found to be strongly charged with sulphurated hydrogen ... (which) blackened silver powerfully, and gave copious precipitates ... ". In 1931 Eggleton also noted the "foul odor of deeper mud deposits" and speculated that Green Lake might be stagnate, characterized by "incomplete spring and fall overturns" and perhaps a complete lack of whole-lake circulation. Eggleton's (1931) account of Green Lake is believed to be the first of a meromictic lake anywhere in North America (Thompson et al., 1990). Following his early assessment, Eggleton (1956) also reported results of a 25-year study of Green Lake concluding that "for all practical purposes, there is no significant amount of dissolved oxygen in the water below 19-20 m at any time of the year" (Thompson et al., 1990).
More recent studies have confirmed Eggleton's pioneering work on Green Lake, while enhancing our understanding of why Green Lake is meromictic. Of particular importance are publications by Deevey et al. (1963), Turano and Rand (1967), Takahashi et al. (1968), Brunskill and Ludlam (1969) and Torgensen et al. (1981). Based on a study of sulfur and carbon isotopes in Green Lake, Deevey et al. (1963) noted unusual quantities of sulphate which they suggested were derived from nearby outcrops of Silurian gypsum entering the lake as surface waters and perhaps "gypsiferous springs". Deevey et al. (1963) concluded that geochemically, Green Lake is more akin to Gulf Coast salt dome systems than to most temperate lakes.
In 1965, Turano and Rand (1967) conducted a series of measurements on the temperature and water chemistry of Green Lake from late winter (February 25) to early spring (April 18). They found that waters of the mixolimnion are colder (3-5°C) than waters below the chemocline (∼7°C). However, surface water temperature of Green Lake varies greatly (3-22°C) as a function of season whereas the monimolimnion maintains a relatively constant temperature of ∼7°C (Fig. 7; Brunskill and Ludlam, 1969).
Turano and Rand (1967) also found that dissolved oxygen concentrations are highest in the mixolimnion >e;10 ppm) of the lake, decrease abruptly between 16 and 19 m and then remain relatively stable to the bottom of the lake (Fig. 7), consistent with previous results. However, unlike Eggleton (1956) who reported that the monimolimnion of Green Lake was completely devoid of oxygen, Turano and Rand (1967) did detect very low levels of oxygen (∼1 ppm). Based on these data they concluded that the monimolimnion of Green Lake is not completely stagnant but rather must have some exchange with other waters, perhaps groundwater. However, Turano and Rand (1967) are the only investigations who have reported some oxygen below the chemocline.
Turano and Rand (1967) also found that both sulfate (oxidized) and sulphide (reduced) increase below the chemocline (Fig. 8) but that only sulphate is present above the chemocline. In the monimolimnion, sulphide concentrations are high (up to 50 ppm) representing a "very considerable quantity" of H2S (Turano and Rand, 1967). Maximum concentrations of sulphide occur near the bottom of the lake suggesting a source via the degradation of organic matter in the sediment primarily by sulfur reducing bacteria (Turano and Rand, 1967). However, sulphide is also oxidized by purple, photosynthetic bacteria that inhabit the chemocline in Green Lake (Culver and Brunskill, 1969). The abundance of sulphide in the monimolimnion and absence in the mixolimnion, of Green Lake, though, is directly related to oxygen concentrations.
Carbon dioxide and pH values in Green Lake are mirror images of each other (Fig. 9): CO2 concentrations are relatively low in the mixolimnion and high in the monimolimnion whereas just the opposite is true for pH (Turano and Rand, 1967). CO2 concentrations are controlled largely by photosynthesis above the chemocline and decomposition of organic matter below the chemocline. pH (a negative measure of hydrogen ion concentration) is inversely controlled by CO2 concentrations. However, pH values are neutral or above (∼7.2-8.0) throughout the entire water column of Green Lake (Fig. 9).
Turano and Rand (1967) also used data on water hardness (Ca, Mg concentrations), alkalinity, pH and temperature to calculate the saturation state of Green Lake with respect to calcium carbonate, both above and below the chemocline. They found that both water layers of the lake are "considerably supersaturated" with respect to calcium carbonate which should promote the precipitation of large quantities of marl.
In 1968 Takahashi et al. published their geochemical study of Green Lake. Although Green Lake had traditionally been believed to be meromictic because of "its great depth ... and small area ... " (Deevey et al., 1963), Takahashi et al. (1968) concluded that Green Lake's meromixis is a result of two different water types entering the lake. Below ∼18 m groundwater entering the basin must be nearly twice as saline as surface waters, regardless of temperature (Takahashi et al., 1968). They found that surface waters are 4x10-4 g/cm3 less dense than deep water. Thus, the permanent stratification of Green Lakes can be fully explained by salinity differences, which is contrary to most lakes which stratify due to temperature-controlled differences in density. This is verified by conductivity (a gross measure of salinity) measurements in Green Lake which display an abrupt increase at ∼18 m water depth (Fig. 10; Brunskill and Ludlam, 1969). Thus, the meromixis of Green Lake is the consequence of a chemically-controlled density boundary or chemocline. However, the salinity of Green Lake is controlled not by Na and Cl as in the oceans, but rather by Ca and S04 derived from gypsum in surrounding bedrock (Takahashi et al., 1968).
That the chemocline in Green Lake is the result of the inflow of saline groundwater is further supported by chemical studies of interstitial waters recovered from bottom sediments. Brunskill and Harriss (1969) found that interstitial waters in a core from the deep (>50 m) central basin of Green Lake show continuous increases of Na, Mg, Sr, Ca, Cl and Br with depth indicating the mixing of monimolimnetic waters with more saline groundwater diffusing upwards into the bottom sediment.
Takahashi et al. (1968) also estimated the residence time (the amount of time a water molecule resides in the lake before being removed) of waters in Green Lake. It had previously been known that the surface outflow of Green Lake exceeds the surface inflow by about an order of magnitude (Turano and Rand, 1967); thus, there must be appreciable inflow of groundwaters. Because of this, plus the meromictic nature of the lake, considerable differences in residence times might be expected. Takahashi et al. (1968) indicated a residence time on the order of only 2 years for surface waters whereas deep waters are replaced no less than once every 35 years. Brunskill and Ludlam (1969) concurred with the short surface water residence times estimated by Takahashi et al. (1968), and further argued that surface inflow supplies <50% of water flow into Green Lake. Based on 3H-3He water mass ages in Green Lake, Torgensen et al. (1981) have confirmed the short residence times of the mixolimnion. However, they concluded that the residence time of water in the monimolimnion is considerably less than previously reported, ranging up to only ∼7 years. Torgensen et al. (1981) also present evidence for a secondary chemocline at ∼33m where there is a significant increase in the concentration of S, CH4, CO2, Na, and Cl. They explain both the short residence time of the monimolimnion and the secondary chemocline as a consequence of diffuse groundwater input.

STOP 3. Precipitation of Calcium Carbonate
From Stop 2, near the dive platform of Green Lake, we will continue our clockwise walk around the lake to Deadman's Point, located at the eastern junction of the "neck" and main basin of Green Lake. Here we will first discuss the seasonal, open water precipitation of calcium carbonate ("whitings") from Green Lake, followed by a discussion of littoral zone precipitation and the formation of the prominent "reef" or bioherm that we will see at Deadman's Point.
Whiting Events
One of the most commonly asked questions about Green Lake is "Why is it green"? Well, the truth is that the lake is not always green. During winter (when not frozen) and early spring months, open waters of the lake tend to be blue, whereas they become green from late spring through fall, when most people visit the Park.
The color of water in a lake varies largely as a function of the amount and type of particulate matter in the water column. Oligotrophic (low nutrient) lakes with little particulate matter, like Skaneateles Lake, tend to display a blue color, whereas those lakes with high concentrations of particulate matter from primary biological productivity, like Oneida Lake, tend to be green, especially during the summer. The reason for this is that clear water scatters light predominantly from the blue portion of the electromagnetic spectrum, whereas when the amount of particulate matter increases in the water column longer wavelength radiation is preferentially scattered, and the lake appears green (Wetzel, 1975).
Green Lake is an oligotrophic lake (Thompson et al., 1997) with annual primary productivity estimated at ∼290 g C/m2 (Culver and Brunskill, 1969). However, ∼83% of this annual primary production in Green Lake occurs within the primary chemocline (∼18 m water depth) due to the photosynthetic activity of purple sulfide oxidizing bacteria. Obviously, an alternative explanation for the seasonal green color of Green Lake is required. A hint comes from Wetzel's (1975) statement that lake sediments rich in light-colored calcium carbonate (marl) reflect more light than non-marl sediments, and that lakes with large amounts of suspended calcium carbonate backscatter energy from the green spectrum of visible light.
The abundance of calcium carbonate deposits in Green Lake has long been known (Clark, 1849; Bradley, 1929, 1963; Howe, 1932; Eggleton, 1956; Brunskill, 1969). Takahashi et al. (1968) as well as Brunskill (1969) documented that the entire water column of Green Lake is supersaturated with respect to calcium carbonate. However, based on δ13C data, Takahashi et al. (1968) concluded that calcite precipitates only from the surface waters of Green Lake. They showed (via data from Deevey et al., 1963) that calcite crystals from the sediment of Green Lake have a δ13C (a measure of the ratio of 13C/12C) value of -4 ‰, which is much more similar to that of surface waters (-7 ‰) than to waters below the chemocline (-18 ‰). By independent means Brunskill (1969) also showed that a 3-4 fold increase in calcite supersaturation occurs in the mixolimnion of Green Lake from May through August, which is the time of massive precipitation of calcite at rates as high as 2 g/m2/day. From sediment trap studies, Brunskill (1969) found calcite crystal loads in the water column of 35 g/m2 in June and July of 1967 (Fig. 11). He argued that the precipitation of calcite in Green Lake is an inorganic process controlled largely by seasonal temperature change- " ... temperature is the direct causal factor in the initiation of calcite precipitation ... with photosynthesis playing only a secondary, and probably minor, role" (Brunskill, 1969, p. 844).
However, this concept of a purely inorganic origin for calcite precipitation in Green Lake has recently been challenged by Thompson and Ferris (1990) and Thompson et al. (1997). Based on experimental and transmission electron microscopy results of waters collected from Green Lake, Thompson and Ferris (1990) concluded that calcite precipitation is the direct result of the photosynthetic activity of the cyanobacterial pico plankton (0.2-2.0 µm) Synechococcus which occurs at concentrations of ∼105 cells/ml of water in the mixolimnion of Green Lake. They convincingly demonstrated that calcite (as well as a gypsum and perhaps magnesite) precipitates epicelluarly around Synechococcus cells (Fig. 12). The reason for this is that the photosynthetic metabolism of Synechococcus directly results in the alkalinization (increase pH) of the microenvironment immediately surrounding the cell because of its ability to use bicarbonate (HCO3-) as a carbon source which results in the production of hydroxyl (OH-) ions (Thompson and Ferris, 1990). Calcium (Ca2+) ions which concentrate on the surface of Synechococcus cells serve as nucleation sites for the precipitation of calcite and gypsum (Fig. 13).
This new view of Green Lake "whiting events" (direct precipitation of fine-grained calcite from the open water column) was further tested by direct monthly field measurements from May 1989 to April 1990 (Thompson et al., 1997). Secchi disk data (Fig. 14) clearly document the onset of the annual Green Lake whiting in May, when water clarity diminishes dramatically (Secchi disk readings decrease from 18 to 8 m). Minimum water clarity (Secchi disk readings of 4.5 m) occurred during July and August and then gradually improved through fall, winter and early spring (Thompson et al., 1997). During this whiting event the color of Green Lake changed from bluish-green to greenish-white (Thompson et al., 1997).
The onset of this whiting event was directly related to the spring bloom of Synechococcus triggered by increasing temperatures and light intensities (Fig. 15; Thompson et al., 1997). That Synechococcus is directly responsible for the precipitation of calcite is supported by δ13C data which reveal that whiting calcite (as well as sediment calcite) in Green Lake is enriched by -3-5 %0 relative to the δ13C of dissolved inorganic carbon (DIC) of summer surface waters (Thompson et al., 1997). The reason for this isotopic enrichment is the preferential uptake of relatively light 12C by the photosynthetic picoplankton (Fig. 16). According to Thompson et al. (1997) individual cells of Synechococcus can precipitate calcite crystals a number of times per season because they periodically shed their outer "S-layer" once it is mineralized.
To summarize, the reason that Green Lake is green (particularly during spring and summer) is because of the widespread precipitation of calcium carbonate. Calcite crystals precipitated around picoplankton result in an increase of particulate matter in the water column which preferentially scatters back green light. In addition, the accumulation of calcium carbonate in littoral zone waters of Green Lake provides a permanent surface of reflection for wavelengths within the green spectrum of visible light.
Bioherms
Here at Stop #3 we can literally stand on a massive, in situ accumulation of calcium carbonate or bioherm. Although the best developed bioherms in Green Lake are here at Deadman's Point, they are also found across the lake along the south-facing shoreline (Fig. 17). These unusual littoral zone accumulations of massive carbonate in Green Lake have been known for many decades (Walcott, 1914; Bradley, 1929; Howe, 1932; Eggleton, 1956). The bioherms of Green Lake have traditionally been viewed as algal in origin, a concept most recently advocated by Dean and Eggleston (1975), Eggleston and Dean (1976), Dean (1981), and Dean and Fouch (1983). In fact, Dean and Eggleston (1975) compared these freshwater bioherms of Green Lake to marine algal "cup" reefs of Bermuda. However, Thompson et al. (1990) have reinterpreted the "algal bioherms" of Green Lake as thrombolitic microbialites which simply means a massive carbonate accumulation precipitated by microbes (rather than algae). SCUBA observations here at Deadman's Point revealed that the microbialites have grown up and out from dolostone beds within the Syracuse Formation. They are lobate features that protrude as overhangs into Green Lake and are as much as 10 m thick (Fig. 18). The undersides of the overhangs are colonized by aquatic mosses as well as sponges, and have laminated stromatolitic caps (Thompson et al., 1990). The internal structure of these features is characterized by a non-laminar, clotted texture. The active, outer growing portion of these bioherms is heavily colonized by a benthic variety of Synechococcus (Thompson et al., 1990). They believe that this benthic species of cyanobacteria, rather than algae, is responsible for the in situ development of the bioherms in Green Lake. Synechococcus is specifically adapted for life in oligotrophic, hard water lakes like Green Lake because of its ability to directly use bicarbonate (HCO3-) as a carbon source and its very low nutrient requirements (Thompson et al., 1990).
Benthic forms of Synechococcus colonize most any hard surface in the lake as evidenced by the accumulation of calcite on human artifacts such as bottles and cans (Fig. 19; Dean and Fouch, 1983). It is also common to see a white calcite coating on trees that have fallen into the lake. However, if one assumes that the bioherms at Deadman's Point originated shortly after Green Lake formed (∼11-12 ka) their growth rate would only be ∼1 mm/year (Thompson et al., 1990).
Before leaving Deadman's Point for our next stop, please take a few minutes to examine the marl deposit which extends to ∼1 m above present day lake level. This calcite-rich deposit contains an abundance of lacustrine, littoral zone gastropods, thus providing clear evidence for a previous highstand of Green Lake (Eggleton, 1956). Harmon (1970) assumed that the level of Green Lake dropped when the Erie Canal (which is located just north of Green Lake; Fig. 1) was built in the early 1800's. However, as we will see at our next stop, there is a well preserved record of natural lake level fluctuations beneath the wetland which connects Green and Round Lakes.

STOP 4. Wetland Stratigraphy and Natural Lake Level Fluctuations
From Deadman's Point we will continue our clockwise journey to the southern end of Green Lake. Here the path will divide and we will bear to the left. This will take us along the intervening wetland between the two lake basins(Figs. 2 and 3). We will stop at the next juncture of the path at the east end of Round Lake to present the subsurface stratigraphy of the wetland and discuss its implications for natural lake level fluctuations as well as regional paleoclimate change over the past -8,000 years. Sediment cores previously recovered from the wetland will be available for viewing and discussion at this stop.
During the summer of 1996 we collected sediment cores, up to 11.2 m long, from three sites in the wetland between Green and Round Lakes (Fig. 20). There is at least 11 m of sediment beneath both the eastern and western ends of the wetland (Fig. 20). However, at the middle site only ∼5 m of sediment was recovered before terminating on what appeared to be bedrock. If correct, there is a very shallow bedrock sill separating the Green and Round Lake basins.
Most of the sediment recovered at all three sites is fossiliferous marl consisting of 60-90% calcium carbonate (Figs. 21 and 22). The abundance of lacustrine fossils indicates deposition in relatively shallow, oxic waters (i.e.littoral zone). However, a number of organic-rich (up to 90%) peat layers, representing various wetland environments, were also recovered and radiocarbon dated (Fig. 21). Based on radiocarbon data, the cores extend back to ∼9.1 ka 14C. Average sediment accumulation rates for the long cores are on the order of ∼1.2 m / 1000 years, although intervals of marl have accumulated at rates of up to 2.6 m / 1000 years (Fig. 23).
Of particular interest is the series of marl-peat cycles (N=4) recovered at core site GL WL-3 nearest to Green Lake (Fig. 22). The four peat layers have been radiocarbon dated (University of Texas Radiocarbon Lab #'s TX-9191, TX-9136 through TX-9133), from bottom to top, at 7,570±70 years, 5,620±70 years, 4,545±65 years, and 2,169±;50 years. Calculation of an average period for these cycles yields an average of ∼1800 years (range 1075 to 2385).
The marls obviously represent open lacustrine connections between Green and Round Lakes whereas the peats represent wetland environments similar to those that exist today. The modern surface peat has developed during the past -∼2,000 years. Thus, it seems highly unlikely that the marl outcrop that we saw ∼1 m above modern lake level at Deadman's Point was stranded by an anthropogenic lowering of lake level less than 200 years ago during construction of the Erie Canal. This is supported by tree-ring counts from the wetland which indicate that living trees predate the construction of the Erie Canal (Brunskill and Ludlam, 1967).
The marl-peat cycles most likely record natural fluctuations of relative lake level approximately every 2,000 years over the past 8,000 14C years. If we interpret such natural lake level fluctuations (Fig. 24) as products of regional changes in precipitation minus evaporation, the data further imply relatively dry climatic conditions at ∼8 ka, 6 ka, 4 ka, and 2 ka with relatively wet climates in between. This is consistent with results from a recent series of cores collected from the Montezuma wetlands (north end of Cayuga Lake) which also revealed relatively dry events at ∼8 ka, 6 ka, and 4 ka (Mullins, in prep.). Thus, the relative lake level fluctuations recorded from the wetland in Green Lakes State Park are likely a response to regional climate changes rather than local drainage basin effects.
The ∼8 ka 14C relative lake lowstand at Green Lakes coincides with the end of a cool, dry period (10.1-8.2 ka 14C) defined by stable isotope data from Seneca Lake (Anderson et al., 1997). This event followed the well-known Younger Dryas cold interval (∼10.8-10.3 ka 14C), and was correlative with a rapid phase of melting of the Laurentide ice sheet which poured large volumes of cold, isotopically light meltwater into the Great Lakes (Anderson et al., 1997). It also occurred quite close (∼7.5 ka 14C) to a recently discovered North Atlantic cool/dry event defined in Greenland ice cores (Alley et al., 1997).
The ∼6 ka 14C relative lake lowering defined at Green Lakes may also be a reflection of broader scale climate changes. In her review of natural lake levels throughout eastern North America, Harrison (1989) discovered that lakes here in general reached their lowest levels ∼6 ka 14C, implying widespread drought for at least a short interval of time. Cores from Montezuma wetlands also display a marked drop in the percentage of calcium carbonate at this time, implying relatively dry and/or cool conditions (Mullins, in prep).
The ∼4 ka 14C relative lake drop at Green Lakes coincides with widespread regional peat development, which effectively ceased marl deposition in the Finger Lakes region (Mullins, in prep.) Approximately 4 ka also marks the end of the mid-Holocene Hypsithermal (∼9-4 ka 14C) in central New York State, which was mostly relatively warm and wet (Dwyer et al., 1996).
Why relative lake level fluctuations in Green Lakes should occur every -2000 years is open to speculation. Perhaps they are related to regional climate changes caused by changes in the production of North Atlantic Deep Water (and thus heat transport) which presumably caused the Younger Dryas climate reversal (Broecker et al., 1989); or, perhaps they are related to shifts in the mean position of the jet stream and atmospheric pressure systems (Dwyer et al., 1996). However, there may also be an intriguing relationship between lake level fluctuations at Green Lake and natural variations in solar irradiance caused by sunspot activity. Wigley and Kelly (1990) have developed a proxy for prehistorical solar variation based on the difference between tree-ring counts and 14C age, which they as well as Karlen and Kuylenstierna (1996), have used to explain Holocene climate changes. The peats dated from the Green Lake wetland match-up well with relatively high amounts of solar irradiance at ∼8 ka, 6 ka, 4 ka and 2 ka 14C (Fig. 25). Greater amounts of solar energy at these times may have led to increased rates of evaporation and thus, relative lake-level lowerings. Although this potential linkage between solar variability and lake levels is speculative, it is certainly deserving of further thought and investigation.

STOP 5. Environmental Changes During The Past 2,500 Years
Short Cores From The Deep Lake
From our previous vantage point of the wetland between Green and Round Lakes we will continue to proceed clockwise around Round Lake. During the course of this part of the fieldtrip keep a sharp eye out for littoral zone bioherms similar to (but smaller than) those at Deadman's Point as well as marl benches indicative of a previous high stand(s) of lake level. At the southwest end of Round Lake we will also be able to observe the inlet to the lake as well as the ∼100 ft. (30.5 m) high cliff over which a late glacial waterfall presumably flowed to carve out this plunge-pool basin. We will then walk, uninterrupted, around all of Round Lake, past the north-side of the wetland, and back to Green Lake before our next stop. Our final stop (#5) will be along the path on the northwest side of Green Lake (across from Deadman's Point) which will afford us an open view of the circular, deep water basin of Green Lake (Figs. 2 and 3).
Because of the seasonal precipitation of calcium carbonate (whitings) coupled with the anoxic nature of waters below the chemocline, sediments in the deep main basin (and part of the "neck") of Green Lake are characterized by distinct annual laminations or varves (Fig. 26). Using sediment trap data Brunskill (1969) was able to document the summer accumulation of a light tan calcite laminae and the winter accumulation of a dark homogenous laminae of more organic-rich sediment; thus, proving the annual nature of these laminations (i.e.-varves). Ludlam (1969) further documented that the light colored laminae contain an average of -82% calcium carbonate whereas dark laminae contain only ∼55%. Average thickness of the more recent varves is on the order of ∼0.7 mm.
Ludlam (1969) also noted that not all sediments below the chemocline are varved; there is also an abundance of massive or "unlaminated" sediment. Because some of these massive layers (mm to cm scale) are graded, have erosional bases and contain coarse littoral zone grains, they have been interpreted as turbidites (Fig. 26; Ludlam, 1969, 1974). We have also recovered deep lake sediments from Green Lake which contain coarse gastropod shells and other material which has obviously been derived and transported from much shallower depths. There is also very good photographic evidence (Fig. 27) for the deformation of varves via subaqueous slumping (Ludlam, 1974; Dean and Fouch, 1983). Thus, there is little question that mass wasting and sediment gravity flows are processes that operate in Green Lake.
However, Ludlam (1969, 1974) has interpreted all massive layers (even those ∼1 mm thick) as turbidites and estimated that 40-65% of basinal sediments in Green Lake were deposited as gravity flows. We do not agree with this assessment which evolved largely in the late 1960's and early 1970's when turbidity current theory was being developed and widely applied. Many of the massive layers we have examined display no objective evidence for deposition by turbidity currents; they are not graded, do not contain displaced grains, and do not have erosional bases. In fact our core 6 from the central basin of Green Lake contains relatively few unequivocal turbidites (Fig. 28). Although this does not mean that all the massive layers are not turbidites, it does highlight a need for additional hypotheses. An alternative interpretation is that these massive layers (particularly the thin 1-2 mm thick ones) are simply thicker than normal winter layers of annual couplets (varves). In fact, Ludlam (1981) stated that" ... thin turbidites ... can not be separated from the annual layers" (p. 85). At the time of this writing, we are conducting compositional analyses and detailed varve versus radiocarbon chronologies in an attempt to develop objective criteria for the origin of many of these "massive layers" in Green Lake.
The accumulation rate of profundal sediment in Green Lake has also been found to be variable, both temporally and spatially. Ludlam (1981) noted a 48% increase in sedimentation rates between the late 1800's and the 1970's. Ludlam (1984) also discovered that sedimentation rates in the "neck" of Green Lake are ∼27% higher than they are in the main basin, perhaps due to the reworking and focusing of sediment from shallow water.
During the summer of 1996 we collected short (<50 cm) gravity cores at seven sites in Green Lake (Fig. 20) with the objective of using the annual deposits (varves) as high-resolution recorders of relatively recent environmental change. We have focused on a pair of cores recovered at site 6 from the floor of the central basin because they contain the lowest ratio of varved sediments to gravity flow deposits (i.e.-turbidites). Because massive zones are interpreted as instantaneous events, they were subsequently subtracted from the final varved sediment record, thus yielding a total varved section of 32.5 cm. Dating of the core is based on four approaches: (1) varve counts; (2) a radiocarbon date on terrestrial organic matter; (3) geochemical correlation with a core dated by 210Pb techniques (Whalen and Lewis, 1980); and, (4) recognition of a pink varve deposited in 1963 (Ludlam, 1969; Ludlam, 1984). The base of the varved section is ∼2500 years B.P. (504 B.C.; Fig. 29) and is thus a record of both natural and anthropogenic processes. Sediment accumulation rates between 2500 years B.P. and 167 years B.P. (1830 A.D.) averaged ∼10 cm/1000 years versus ∼70 cm/1000 years over the past 167 years.
Loss-on-ignition results for total calcium carbonate content in core 6 display a marked decrease at the same depth (18.5 cm) where accumulation rates increase by nearly an order of magnitude (Fig. 30). Average total carbonate values drop from ∼80% prior to 1830 A.D. to ∼60-65% after 1830 A.D. (Fig. 30). In contrast, average total organic matter contents in core 6 remain relatively constant at ∼10% both prior to, and after, 1830 A.D. These data indicate that starting in ∼1830 A.D., the flux of terrigenous material to Green Lake increased significantly resulting in increased rates of sediment accumulation (Fig. 30). This is supported by mineralogical data (determined by X-ray diffraction) which show an abrupt increase in the relative abundance of detrital quartz and dolomite at ∼1830 A.D. (Fig. 31). Prior to 1830 A.D. dolomite is generally absent from core 6 and quartz is only a minor component. Trace element data (determined by direct current plasma emission spectrometry) of the carbonate fraction in core 6 also display a marked change at ∼18.5 cm depth. Concentrations of Pb, Mg, Mn, Cu, and Fe all increase above this depth, whereas Ca and Sr decrease. Lead (a common anthropogenic element) is of particular interest (Fig. 32). Prior to 1830 A.D. lead concentrations range from 5 to 55 ppm with an average ∼25 ppm; whereas, after 1830 A.D. Pb concentrations range from 35 to 105 ppm with an average of ∼70 ppm (Fig. 32).
Collectively, these results argue for a significant anthropogenic influence on sedimentation in Green Lake since ∼1830 AD. Whalen and Lewis (1980) have previously proposed that deforestation of the region in the early to middle 1800's increased surficial runoff and the flux of terrigenous material into Green Lake. Our results are consistent with their suggestion. Pollution of surface waters by heavy metals at this time might also explain the observed increases of Pb, Cu and Fe since 1830 AD., although these metals may have also entered the Green Lake basin via the atmosphere as a by-product of coal burning starting with the industrial revolution. We have also sampled (N=48) varves from core 6 for stable isotope analysis in order to evaluate both natural and potential anthropogenically-influenced climate changes over the past 2500 years. These new data represent the first stratigraphic stable isotope results for Green Lake since a brief mention of results by Stuiver (1968,1970). δ18O (a measure of the 18O/16O ratio) values vary by as much as ∼2 ‰ over the length of the core (Fig. 33) which is 1 ‰ greater than the variability indicated by Stuiver (1968). δ18O values also display a gradual depletion from ∼10.2 %0 to ∼10.7 %0 between 500 B.C. and 200 AD. If this entire depletion (∼0.5‰) is due solely to temperature change (0.34 ‰/1 °C; Rozanski et al., 1993; Anderson et al., 1997) it would imply regional spring/summer cooling of up to 1.5°C. 2 However, some or all of this isotopic change could also be due to shifts in atmospheric moisture sources. In this case more depleted δ18O values would imply an increase of moisture from Pacific, Canadian or North Atlantic air masses, which all tend to be cooler than the warm, isotopically heavy air masses which advect into central New York State from the Gulf of Mexico (Rozanski et al., 1993). 2 In terrestrial records, such as ice cores or lake sediments, δ18O depletions imply relative coolings due to latitudinal fractionation of 18O. This general relationship is opposite that for marine records. This isotopic evidence for a modest cooling trend between 500 B.C. and 700 A.D. is consistent with ice core data sets which indicate global cooling during the past 4-5 ka following the mid-Holocene Hypsithermal (Larsen et al., 1995; Thompson et al., 1995). Both glacier reconstructions (Nesje and Kvamme, 1991) and general circulation models (Liao et al., 1994) indicate that Hypsithermal summer temperatures were 2-3 °C warmer than pre-industrial modem values, due to precessional changes.
Following an extreme δ18O depletion event (one data point) of ∼1 ‰ at ∼1250 A.D. δ18O values remain relatively constant until the early to middle 1800's and "colder" than modem values. Since then, δ18O values become enriched (heavier) by as much as 1 %0, although there is significant variability (Fig. 33). The increased variability is due in part to a lower sampling interval afforded by the higher accumulation rates after 1830 A.D. Whereas the pre-1830 A.D. average sampling interval is 1 sample per 90 years, the interval increases to about 1 sample every 14 years after 1830 A.D. allowing resolution of decadal scale variability.
It is tempting to speculate that the enrichment (warming) of δ18O values from Green Lake after the early 1800's is related to the anthropogenic rise of atmospheric carbon dioxide and global warming since the early to middle 1800's (Keeling et al., 1989). Absolute δ180 values over the past -150 years are as heavy as ∼9.3 %0 which is unprecedented over the 2500 year record in core 6 (Fig. 33). However, a 1 %0 increase in δ180 would indicate an ∼3 °C summer temperature rise, assuming that the entire isotopic shift is temperature dependent. Mean global surface temperatures have risen by only ∼0.5 °C since the mid-1800's. However, part of this observed increase in δ18O values from Green Lake over the past ∼150 years could also be due to an increase of moisture from warm, isotopically heavy Gulf of Mexico air masses, and/or evaporative enrichment.
To elucidate the potential causes of enriched and depleted δ18O values in Green Lake throughout the last century, a calibration using regional climate data was performed. Figure 34 shows the graphical comparison of δ18O values from ∼1900 to 1980 A.D. with yearly average summer temperatures for Syracuse, N.Y. When the temperature data is smoothed (a 15% running average function was utilized to remove inter-annual variability) decadal trends are evident that display a remarkable correlation (r=.86) with δ18O values (Fig. 34). Periods of cooler temperatures (1910 to 1930 and 1950 to 1970) correlate with isotopically depleted values while warmer periods (1900's and the late 1930's to early 1940's) correlate with isotopically enriched values. However, if the δ18O values were solely recording surface water temperatures in Green Lake during these periods, the exact opposite relationship would be observed (i.e. cool periods represented by isotopically enriched values). Therefore, the dominant control on the δ18O carbonate signature must be a function of the water composition in Green Lake, which is largely controlled by the type of airmass bringing precipitation into the area. As stated above, enriched values could be due to an increase of moisture from warmer temperature, isotopically heavy Gulf of Mexico source air masses while depleted values may result from cooler temperature, isotopically depleted Canadian or Pacific source air masses. Because Green Lake lies directly below the modern day position of the jet-stream, and the position of the jet-stream controls the type of airmass coming into the region, the Green Lake δ18O record provides a very sensitive proxy for jet-stream fluctuations and climate change.

B1: STRATIGRAPHIC INCOMPLETENESS: MILANKOVITCH IN THE MANLIUS AT THE MARGIN
Peter W. Goodwin and E. J. Anderson
Philadelphia, P A 19122
As a result of lower subsidence rates, stratigraphic sections at basin margins are less complete than those in shelf and basine positions. Determining degree of incompleteness and its specific stratigraphic location or locations have been difficult tasks dependent on the accuracy of detailed chronologic correlations from complete basinal sections to less complete marginal sections. In the Helderberg Group (Fig. 1), large-scale models of gradual stratigraphic accumulation (e.g. Rickard, 1962: Laporte, 1969) were able to recognize major group-bounding unconformities, but did not identify internal smaller-scale unconformities. Using a model of small-scale episodic accumulation of time-stratigraphic allocycles, Goodwin and Anderson (1986, 1988) recognized cryptic unconformities internal to the Helderberg Group, surfaces at which detailed correlation of cycles revealed missing cycles (Figs. 2 and 3).
One such unconformity, traced from the Hudson Valley westward to the Syracuse area (Figs. 2 and 4), was interpreted as a sequence-bounding unconformity separating tectonically distinct portions of the Helderberg Group (Goodwin and Anderson, 1988). That third-order unconformity is the Manlius-Coeymans contact in the Hudson Valley and the Thacher-Olney contact in western sections (Fig. 1). Lesser unconformities, with fewer missing cycles, were recognized in the Manlius, but not fully explained (Fig. 2). It is the purpose of this trip to examine stratigraphic discontinuities of all scales within the Manlius Formation at four localities on the western margin of the Helderberg Basin, and to explain these unconformities in the context of the hierarchic model of orbital forcing.

B1: Stratigraphic Incompleteness: Milankovitch in the Manlius at the Margin

STOP 1. Manlius Formation at Munnsville Quarry
(Rickard Loc. 137)
The Munnsville Quarry Manlius section begins in the Thacher Member at the quarry entrance and continues into the Olney Mbr. on the north wall of the quarry. The upper Olney, Elmwood, Clark Reservation and Jamesville members are exposed in the west wall of the quarry.
At this locality, a third-order unconformity forms the Thacher-Olney contact (Fig. 8); extended eastward this unconformity becomes the Thacher-Ravena contact at Schoharie and in the Hudson Valley (Figs. I and 2). Between this unconformity and the fourth-order boundary at the base of the Clark Reservation Mbr. the OlneyElmwood interval (46.5 ft thick) consists of four relatively complete fifth-order sequences (A, B, C and D). Each of these fifth-order sequences consists of four or five sixth-order sequences (PACs). The fourth-order sequence below the unconformity consists of portions of two fifth-order sequences (A and B), the upper two missing by vacuity (erosion) at the unconformity.

STOP 2. Clockville Roadcut
(Thacher-Olney Interval, Manlius Fm., Rickard Loc 142) .
At this locality, the Thacher Mbr. and the lower Olney Mbr. are exposed. The described section (Fig. 9) begins near the top of the thick-bedded Thacher of Rickard (1962). The third-order unconformity (Thacher-Olney contact) is exposed near the top of the outcrop. The Olney-Elmwood portion of the columnar section was described at Perryville, 3.5 miles to the West.
As at Munnsville (Fig. 8), the fourth-order sequence below the unconformity consists of two incomplete fifth-order sequences (A and B). The smaller number of sixth-order cycles in fifth-order sequence B at Clockville relative to Munnsville suggests slightly deeper erosion at the third-order unconformity at this locality.

STOP 3. Madison Highway Products Quarry, Perryville
(Rickard Loc. 144)
At this locality, the upper Thacher, Olney, Elmwood and Clark Reservation Members are exposed in the north wall of the old pit behind the maintenance shed and scale house. The base of the section begins six feet below the Thacher-Olney third-order unconformity (Fig. 9). The Thacher portion of the column was described at Stop 3.
As at Munnsville, the Olney-Elmwood fourth-order sequence consists of four nearly complete fifth-order sequences (A, B, C and D). The slight difference in thickness (less at Perryville) and the generally more restricted facies at Perryville suggest that this locality is onshore of Munnsville. However, the similar stratigraphic structure of the two sections indicates very little topographic relief between the two localities.

STOP 4. Onondaga County Quarry, Jamesville
(Rickard Loc. 151)
At the Jamesville locality, the section (Fig. 10) begins in the Elmwood Mbr. on the road north of the quarry entrance. The upper Elmwood, Clark Reservation and Jamesville Mbrs. are exposed in the east wall of the quarry.
At Jamesville (Fig. 10), the Olney-Elmwood fourth-order sequence is less complete than at Perryville (Fig.9), consisting of portions of three fifth-order sequences (B, C and D). Sequence A was not deposited because this area remained positive until flooding during the deposition of sequence B. As yet, we have not determined which two sixth-order flooding events in sequence B are recorded at this locality. Similarly, fifth-order sequence D is less complete at Jamesville than at localities to the East. Whether this difference is the result of hiatus at the base of the sequence or erosion at its top has not been determined.

STOP 5. Interstate 81 Roadcut
(Olney, Elmwood, Clark Reservation, Jamesville Mbrs.)
This roadcut south of Syracuse exposes the upper Thacher, Olney, Elmwood, Clark Reservation and lower Jamesville Mbrs. of the Manlius Fm. The Thacher Member is completely exposed in the roadcut of the southbound lanes ofInterstate 81, a locality not visited on this trip.
At this locality (Fig. 11), the Olney-Elmwood fourth-order sequence is even less complete than at Jamesville, approximately 4 miles to the East. As at Jamesville (Fig. 10), the sequence consists of three fifth-order sequences (B, C and D), but sequence B consists of just one sixth-order cycle (PAC). Beneath the third-order unconformity (Thacher-Olney contact), the Thacher fourth-order sequence contains more sixth-order cycles than at localities to the East, indicating that erosion did not cut as deeply (vacuity is less). Still, this fourth-order sequence is far from complete, consisting of just two fifth-order sequences.

B2: HERKIMER DIAMOND MINE FIELD TRIP
Hugh Humphreys
Tibbits Road, New Hartford, NY 13413
Herkimer "diamonds" are doubly-terminated quartz crystals found near Herkimer, New York. The clarity and perfection of these crystals make them one of central New York's most collectable minerals. The crystals are found in muddy pockets, or vugs, up to a meter in diameter in the Late Cambrian Little Falls formation near Middleville, Little Falls and Herkimer, New York. As many as 1000 crystals have been found in a single pocket (Moore, 1989).
This trip will visit the Herkimer Diamond Mine, owned by the Herkimer Diamond Development Co. near Middleville, New York. The trip will be led by Hugh Humphreys. Hugh has been an avid miner and collector of Herkimer diamonds for 15 years. After a visit to the museum at the mine, he will discuss the occurrence of the crystals and will demonstrate different mining techniques. Ample time will be provided for participants to explore the mining area and search for "diamonds." Although this trip is scheduled for a half-day, you may stay as long as the mine is open. The following description is taken from information displayed with Herkimer diamonds in the mineral collection at Hamilton College, Clinton, New York.
The exact origin of the pockets and the quartz crystals is unknown; several related theories exist. One theory is that in Late Cambrian time, quartz sand grains and minor amounts of clay were deposited in a predominantly carbonate environment where there was significant algal growth. The sand, clay, and algae were incorporated into limestone, which was dolomitized by circulating waters. The formation is a rather normal dolostone or dolomitic sandstone.
After burial, entrapped sea water or water from some other source dissolved some of the sand grains, dolomite, and algae to form the pockets. Many pockets today contain a black carbonaceous material called anthraxolite, which may represent an insoluble residue from the algae. Thus, the algae may have served as sites for solution and pocket formation.
As the pH of the water in the pockets decreased, quartz crystals started to grow. The source of the silica was the dissolved sand and clay or the remains of silica-secreting animals such as radiolaria. Some quartz crystals started their growth on the pocket wall and grew into the pocket. Many crystals, however, grew freely in the pocket water or in the mud that was the insoluble residue from pocket formation, allowing the doubly-terminated crystals to form. Most of the crystals are short hexagonal prisms terminated by rhombohedrons.
Some crystals show solid or fluid inclusions. Solid inclusions are usually specks of anthraxolite. Fluid inclusions are mostly salt water with bubbles of CO2 or water vapor. Based on a homogenization temperature of 51°C, the crystals formed at a depth of approximately 3500 feet (Dunn and Fisher, 1954).

Herkimer Diamond Mines

B3: EURYPTERIDS AND ASSOCIATED FAUNA AT LITCHFIELD, A CLASSIC LOCALITY IN HERKIMER COUNTY
Victor P. Tollerton, Jr.
23 Shepherd Place
Utica, New York 13502-5417, mltolrton@borg.com
The Upper Silurian Bertie Formation (Group of D.W. Fisher, 1960; Ciurca, 1973) of New York State and Ontario, Canada, is world renowned for its spectacular eurypterids. One of these, Eurypterus remipes Dekay, 1825, holds the distinction of being the first eurypterid in the world to be described. This species is also the state fossil of New York, as signed into law by Mario Cuomo on 27 June 1984. Another species, the second one in the world to be described, Eurypterus lacustris Harlan, 1834, has been figured on a postage stamp of Canada (as Eurypterus remipes).
Central New York is fortunate to boast of four localities where eurypterids can still be collected from the Bertie (Forge Hollow, Litchfield, Lang's Quarry, and Passage Gulf). Two others mentioned in the literature (Jerusalem Hill and Crane's Corners) are not currently accessible. The Litchfield, Herkimer County locality is a classic outcrop that displays both vertical and horizontal sections amenable for paleoecological study.

B3: Eurypterids and Associated Fauna at Litchfield, A Classic Locality in Herkimer County

STOP 1. Forge Hollow, Oneida County, New York.
BE CAREFUL ... blind curves at both ends of the outcrop.
This locality is the type locality for the eurypterid Eurypteros remipes Dekay, 1825, and the scorpion Proscorpius osborn; (Whitfield), 1885. It is also the type locality for a new genus and species of eurypterid being described.
This outcrop exposes the following units (in ascending order); Camillus Shale; the Morganville, Victor, and Phelps beds of the Fiddlers Green Member, Bertie Formation; Scajaquada Member (= Rickard's 1962 Forge Hollow Member), Bertie Formation; Williamsville Member, Bertie Formation; Cobleskill Formation; and Manlius Formation.

STOP 2. Litchfield eurypterid locality.