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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Note NW-trending drumlins to the west.

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

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

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

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

Roadcut through kame (at sharp turn).

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

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

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

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

Unsorted and unstratified glacial till

Crossing Neversink Valley covered with glacial till

Entering Helderberg Ridge

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

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

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

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

Martinsburg on right (W).

Exposure of Martinsburg on right (W).

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

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

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

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

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

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

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

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

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

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

Large quarry at the right.

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

Sandstone outcrop along railroad on Pa. side of river.

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

Outcrop along railroad on Pa. side.

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

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

Large outcrop of the sandstone on the right.

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

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

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

Cross ten mile river

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

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

Outcrop at right. Notice the abundance of red soil.

Red siltstone exposure at right.

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

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

Red shale and mudstone exposed on both sides of highway.

Outcrop of gray sandstone in Damascus Fm at right.

Red sandstone exposure at right.

STOP 4. Outcrop of the Lower Katsberg Formation.

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

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

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

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

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

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

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

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