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 residium. 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 Campuso
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, fallmaker | 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 Genundewa 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, finegrained 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 Genundewa 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 unfossilliferous. Large blocks of the fall-making Genundewa 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 waterlimes 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 ppe 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 connnon 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