NYSGA 1960
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 r1pple-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 hematit1c sandstone with red and greenish-gray clay galls and prom1nent cross-bedd1ng (Grossman, in Kay, 1953, p. 68).
Still in the Sauquoit are beds of green shale interbedded with fine-grained sandstone. Interference r1pples show well on several beds. These beds are somewhat fossilliferous.
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 prom1nent 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 hamatite at several places in the mine. Oolitic hematite beds in the south branch of Moyer Creek (See Trip A) exhibit well developedcrossbedding. Dale (1953) notes the presence of ripple marks and channel fillings in the overlying fossiliferous Willowvaleformation, and both he and Alling conclude that the oolitic hematite beds are integral members of a shallow water marine depositional sequence.
Tbe 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 gaboro 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 Frecambrian 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 blaok caloareous 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 thiok, and an intraformational 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 anthraxo1ite (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", whioh contains graded sandstone and intraformational 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 inconspiouous 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 ot 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 teet 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 ot 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 teet above the formation base. The uppermost beds are thick calcarenite strata, some ot which have para-ripples.
The Shoreham limestone, overlying the Kirkfield, is 45 teet 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.