NYSGA 1986
NEW YORK STATE GEOLOGICAL ASSOCIATION
58TH ANNUAL MEETING
FIELD TRIP GUIDEBOOK
Department of Geological Sciences
and
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
New York State Geological Association
Department of Geological Sciences and
Cornell University
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
University of Rochester
Rochester, N.Y . 14627
INTRODUCTION
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).

1: SUBMARINE EROSION ON THE DYSAEROBIC SEAFLOOR: MIDDLE DEVONIAN CORRASIONAL DISCONFORMITIES IN THE CAYUGA VALLEY REGION

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
University of Rochester
Rochester , N.Y. 14627
GORDON C . BAIRD
SUNY College at Fredonia
Fredonia, N.Y. 14603
and
KEITH B. MILLER
Rochester, N.Y. 14627
INTRODUCTION
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
Department of Geology
Skidmore College
Saratoga Springs, New York 12866
INTRODUCTION
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
Monroe Community College
Rochester, NY 14623-5780
JONATHAN W. HARRINGTON
Harrington Associates
Consulting Geologists
390 Clark St. Ext.
Groton, NY 13073
WILLIAM T. KIRCHGASSER
Department of Geology
State University College
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
Monroe Community College
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)
Cornell University
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
U.S. Geological Survey
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
Department of Geological Sciences
and
Institute for the Study of the Continents
Cornell University
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.