NYSGA 2005
New York State Geological Association
77th Annual Meeting
Field Trip Guidebook
Edited by David W. Valentino
Hosted by the State University of New York at Oswego
This guidebook was published by the New York State Geological Association.
Additional copies may be obtained from the Publication Manager of NYSGA:
William Kelly
New York State Museum/Geological Survey
3140 Cultural Education Center
Albany, New York 12230
wkelly@mail.nysed.gov

A1: SLOPERVILLE BOG AND ESKERS
Andrew P. Nelson
Biology Department
State University of New York at Oswego
Oswego, NY 13126
INTRODUCTION
On this trip we will explore a large wetland centrally located in a beach, outwash, and esker-kame moraine complex that forms the Lacona-Williamstown aquifer, the largest aquifer in Oswego County. This fieldtrip will use terms commonly used to designate glacially formed topographic features, and address specific names of plants and detailed descriptions of the characteristics of relevant wetland communities.
Sloperville Bog is part of a complex 73.5 ha (183.8 acre) wetland unit located in the northeast corner of the Town of Albion in Oswego County. It is situated in the adjoining west corners of the Orwell and Williamstown 7½' quadrangles. The bulk of the wetland and surrounding uplands are owned by Cotton-Hanlon Inc., having been acquired from a private landowner in 1966. The area has thus been protected from housing and other forms of development and presents a relatively unaltered landscape, flora, and fauna.
Current features of the topography and surficial geology of Oswego County are largely the result of glacial and melt water action during the most recent (Wisconsinan) glaciation and wave and wind action along the shores of proglacial Lake Iroquois and its successors. The ancient shoreline of Lake Iroquois extends south from the northern boundary of the county at approximately 76°03.75'W turning east parallel to the north shore of Oneida Lake at about 43°15'N (Figure 1). The central and western portions of the county, west and south of the Lake Iroquois shoreline, are part of the Erie-Ontario Coastal Plain, much of which features a landscape of drumlins with intervening streams and wetlands. The northeastern portion of the county is part of the Tug Hill Plateau, rising from about 150 m (500 ft) along the Lake Iroquois shore line to about 516 m (1,720 ft) at the northeast corner of the county. The topography here features a complex mix of kames, eskers, kettles, outwash plains, and wetlands. Surficial deposits include extensive areas of ablation till and sand and gravel with scattered pockets of lodgment till (Figure 1) (Miller 1982).
Oswego County is unusually rich in wetlands (sites permanently or periodically flooded or saturated by seepage and supporting emergent wetland vegetation). The 858 wetlands greater than 4.96 ha (12.4 acres) in size or of unusual local importance included in the “The Oswego County Wetlands Mapping Inventory Project” cover a total of 37,200 ha (93,000 acres) representing 15% of the county’s total land area (Jones et al. 1983a).
Wetlands are commonly and broadly categorized according to the nature of the substrate and the physiognomy of the vegetation. Wetlands with a substrate of mineral soil are broadly distinguished as marshes, if dominated by herbaceous plants, or swamps, if dominated by woody plants. Where conditions are such as to limit aeration, partly decomposed plant remains may accumulate resulting in a substrate of organic peat. Most forested peatlands, like forested mineral soil wetlands, are called swamps, the different types characterized by the presence and/or dominance of different tree species. Open peatlands, dominated by herbaceous vegetation and especially those where plant roots and peat form a floating mat, are commonly called “bogs”. Wetland ecologists, however, often reserve the term “bog” for peatlands where the input of water and dissolved minerals is primarily from direct precipitation with little if any contribution from ground water or surface runoff. Bogs in this strict sense have not been found in Oswego County. Floating mat peatlands fed by surface runoff, ground water, or adjacent flowing streams are referred to as “fens”. Fens exhibit a gradation of features allowing identification of “poor fens”, “medium fens” and “rich fens”. A fen built up on the soils of a lake shore or stream floodplain where the mat is periodically inundated instead of floating with changing water levels is sometimes called a sedge meadow (Edinger et al., 2002), though some authors use this term only in association with sedge dominated marshes (Crum, 1988). Any of these open peatlands may be gradually invaded by woody plants turning a rich or medium fen into a shrub fen or a poor fen into a dwarf shrub bog (Edinger et al., 2002).
Eighty eight (88) of the 858 wetlands identified by the 1983 Oswego County wetlands inventory were cited as being or containing “bogs”. Over the last ten years collaborative research with Peter A. Rosenbaum (Biology Department at Oswego) has focused on evaluation of these sites as potential habitat for species of plants and animals recognized as rare and endangered.
The majority of these peatlands (“bogs”) are poor fens of the sort commonly referred to as “kettlehole bogs”. Characteristically, these fens develop in the ponds formed in kettles, localized depressions resulting from thawing of isolated blocks of glacial ice that were buried in ablation till or kame deposits. These basins often have no surface drainage and are fed by surface runoff from a small watershed and/or by ground water. In the classic model, a floating mat of Sphagnum peat develops around the edge of the pond, gradually covers the pond, and eventually fills the basin.
Poor fens are fed by surface runoff and ground water relatively low in mineral content (weakly minerotrophic). The peat is composed mostly of the remains of Sphagnum (peat) mosses with a minor amount of material derived from grass-like (graminoid) plants of the sedge family (Cyperaceae) and from woody plants. pH is quite low ranging from 3.5 to 5.0 (Edinger et al., 2002). The surface of the peat is covered with a nearly continuous layer of living Sphagnum. The Sphagnum peat constitutes a chemical environment in which the low pH is maintained and the common plant nutrients, particularly calcium, nitrogen, phosphorous, and potassium, are bound in forms unavailable to most plant species. Woody plants such as eastern white pine (Pinus strobus), tamarack or eastern larch (Larix laricina), black spruce (Picea mariana), and red maple (Acer rubrum) are often present as stunted, slow growing individuals. Shrubs particularly adapted to growth in acid, low nutrient habitats, many of them in the Heath family (Ericaceae), are usually present and may be abundant. Included here are highbush blueberry (Vaccinium corymbosum), black huckleberry (Gaylussacia baccata), leatherleaf (Chamaedaphne calyculata), bog laurel (Kalmia polifolia), bog rosemary (Andromeda glaucophylla), and small cranberry (Vaccinium oxycoccos). Graminoids in the Cyperaceae commonly include certain species of Carex (sedge), Rhynchospora (beakrush), and Eriophorum (cottongrass). Carnivorous plants, such as pitcher plant (Sarracenia purpurea), sundews (Drosera rotundifolia and D. intermedia), and bladderworts (Utricularia spp.), are abundant. Wild orchids, such as swamp pink (Arethusa bulbosa), grass pink (Calopogon tuberosus), pink ladyslipper (Cypripedium acaule), white fringed orchid (Platanthera blephariglottis), and rose pogonia (Pogonia ophioglossoides), are also characteristic species of this community. Poor fens, highly localized and somewhat unusual in our area, are similar in many ways to the vast muskeg of the taiga, the boreal forest community which circles the globe in more northern latitudes. Like alpine ecological communities at high altitudes, poor fens may remain as relict representatives of more widespread communities that occupied our area as the glaciers receded in the late Pleistocene.
Thirteen (13) of the eighty eight (88) peatland containing wetlands cited in the wetlands inventory support medium fens. Medium fens are fed by moderately mineralized ground waters that, in our area, are probably enriched in calcium as the result of passing through calcareous sands or gravels. In most cases the wetland with which they are associated has a perennial outlet stream. The peat formed in medium fens is a mixture of the remains of sedges, mosses, and woody plants with sedges predominating. Medium fens have a pH of from 4.5 to 6.5 (Edinger et al. 2002). Medium fens we have explored in Oswego County are often situated along the margins of a pond. In these cases, the pH of the pond waters is usually significantly higher (7.0 to 8.8) than that of the bordering fen. Where a sedge-dominated medium fen borders an area of Sphagnum dominated poor fen, the transition from medium to low pH can be as sharp as the visual line that marks the edge of the Sphagnum mat. The dominant plants of medium fens are mat forming sedges such as Carex lasiocarpa, and Cladium mariscoides (bog-rush). Sphagnum mosses are usually confined to hummocks that build up around scattered trees and shrubs or clumps of royal fern (Osmunda regalis). A characteristic shrub of medium fens is sweet gale (Myrica gale). Leatherleaf and the other ericaceous shrubs also seen in poor fens may be present and abundant. The large cranberry (Vaccinium macrocarpon) is more likely to be more abundant than the small cranberry. Black spruce is often absent and northern white-cedar (Thuja occidentalis) and poison sumac (Toxicodendron vernix) are often present as well as eastern larch, white pine, and red maple.
Rich fens, which to our knowledge are not represented in Oswego County, usually occur in areas of carbonate bedrock. The pH of these systems ranges from 6.0 to 7.8. Graminoid peat formed from the dominant sedges may be accompanied by layers of marl. Sphagnum is absent or confined to hummocks. Characteristic sedges include the spikerush Eleocharis rostellata, the bog-rush, and the sedges Carex flava, C. lasiocarpa, and C. hystericina. Other herbaceous plants of rich fens are grass-of-parnassus (Parnassia glauca) and Kalm’s lobelia (Lobelia kalmii). Characteristic woody plants include shrubby cinquefoil (Potentilla fruticosa), bayberry (Myrica pensylvanica), poison sumac, red maple, northern white cedar, eastern larch, sweet gale, and swamp fly honeysuckle (Lonicera oblongifolia).
The classifications that result from study of ecological communities represent, at best, a rough approximation of the actual situation in nature. Boundaries between different types of communities consist of gradients, sometimes abrupt and sometimes gradual, in all recognized parameters. Particular plant species that characterize a wetland community in central New York may not be characteristic of the same community as represented in the lake states or northern New England and a given wetland, like Sloperville Bog, may contain a mosaic of different wetland community types.

A1: SLOPERVILLE BOG AND ESKERS

STOP 1. Sloperville bog
Sloperville bog is part of the largest of three segments of the wetland designated as OR-29 on the Oswego County Wetlands map. Beaverdam Brook enters the wetland from the southeast, threading its way around and through a complex of eskers before expanding into an area of open water in the southern portion of the wetland and then exiting through a constriction at the southwest corner of the wetland immediately south of the south end of Sloperville Drive (Fig. 2). Water is retained in the northern portion of the basin by an undulating esker meandering on an east-west course across the middle of the basin. The dam formed by the esker is completed by beaver dams at two points where the esker is broached or submerged. This northern section receives runoff from a limited watershed. A steady flow of water in the stream draining from the northeastern of the two beaver dam areas suggests a significant and continuing inflow of ground water into the northern part of the basin. The northwestern lobe of the basin supports the extensive poor fen known as Sloperville Bog. Roughly half way across the basin to the east the poor fen changes over to medium fen and marsh dominated by Carex lasiocarpa and then gives way to open water. In the eastern part of the basin immediately below the beaver dams is a sedge meadow traversed by narrow rivulets that drain into the stream draining the northern part of the wetland down to Beaverdam Brook. Further west a shrub fen has developed in a cove bounded by the main esker that extends across the basin (Figure 2). A total of 136 species of vascular plants (club mosses, ferns, conifers, and flowering plans) have so far been recorded from the Sloperville bog wetland. The ecological communities of the southern half of the basin have not yet been intensively explored and characterized.
The poor fen in the northwestern lobe of the basin is perhaps the most easily accessed and negotiated poor fen in the county and for that reason it is a favorite for introducing students to this type of ecological community. The surface of the mat is firm, except at the edges, and virtually flat. The vegetation on most of the fen is low and open posing no obstacle to progress over the surface.
The classic kettlehole bog or poor fen of the glaciated northeastern United States consists of a central pond surrounded by the floating mat of an open fen which gives way at its inland margins to shrubs and eventually trees, the whole comprising a series of concentric zones around the pond. The floating mat of the Sloperville poor fen, in contrast, extends to the edges of the basin separated from the mainland only by a narrow moat where incoming surface runoff supplies sufficient oxygen and mineral nutrients to facilitate decomposition of plant materials. There is a central pond, in this case immediately surrounded by a narrow floating mat consisting primarily of the sedge Carex limosa and dense clumps of leatherleaf. This, in turn, is surrounded by a zone of dense, head high blueberry and huckleberry bushes along with relatively tall black spruce and larch. A few other isolated, smaller groves of spruce and larch also occur in the fen. A total of fifty four (54) species of vascular plants, all more or less characteristic of poor fens in this region, have been recorded from this fen. This includes all of the orchid species so far found in the wetland and most of the carnivorous plants. Except for the thicket surrounding the central pond, the woody plants of this fen are quite stunted compared to individuals in some other poor fens of the area. Dwarf mistletoe (Arceuthobium pusillum), a diminutive parasitic flowering plant, can be found on the branches of some of the black spruce in the thicket on the northeast edge of the central pond area.
Roughly half way across this northern basin some isolated upland islands interrupt the fen. In this area, the poor fen of the western lobe of the basin gives way to a Carex lasiocarpa dominated fen, then to an area of partially submerged C. lasiocarpa and finally to shallow, open water. The restriction of the poor fen to the northwestern lobe of the wetland suggests that there is some limitation on drainage from this section into the rest of the basin. It is tempting to suggest that the isolated islands across the center of the basin may be the exposed portions of a segmented esker the rest of which has been buried by flooding and accumulation of peat and other sediments in the basin (Figure 2) (Jones et al., 1983b). Such a sub-surface ridge might restrict the drainage of water from the western portion of this basin. Investigation of this possibility would contribute greatly to an understanding of the nature of Sloperville Bog.
The medium fen and area of open water in the eastern part of the basin present a complex of habitats from which fifty three (53) species of plants have been recorded. Species characteristic of medium fen, marsh, shrub swamp, and aquatic habitats are included.
Directly down stream from the western of the two beaver dams currently controlling the water level in the large northern basin is a shrubby area leading to the flood plain of the stream draining the basin through the eastern beaver dam (Fig. 2). Seepage from this area flows through shallow, narrow rivulets into the stream running south below the eastern beaver dam. A small pond impounded by a second dam below the main eastern dam provides habitat from which twenty two (22) aquatic and lake shore plant species were recorded on one visit in July 2004. Thirteen (13) of these have not been recorded from other sections of the wetland north of Beaverdam Brook and an additional five (5) have been seen elsewhere only in the medium fen and open water area directly north of the beaver dams.
The flood plain of the stream draining the northern basin supports a sedge meadow dominated by Carex lasiocarpa. Plant species records as currently kept for this area include the shrubby margins of the flood plain as well as the open sedge meadow itself. Sixty three (63) species have been recorded from this area making it the most diverse part of the wetland surveyed to date. The sedge meadow has a level surface consisting of a firmly grounded layer of peat crisscrossed by deer trails and narrow channels draining water into the stream. In addition to Carex lasiocarpa, other species found here that are characteristic of medium fens include yellow sedge (C. flava), marsh bellflower (Campanula aparinoides), marsh cinquefoil (Potentilla palustris), and lesser bladderwort (Utricularia minor). The lesser bladderwort is unusually abundant, flowering in great numbers in the small drainage channels and deer trails in this community. This diminutive plant is rarely noticed outside of its flowering season, two or three weeks in late June to early July. Although it is now known to occur in a variety of shallow water habitats, it seems to have been noticed in flower only in medium fens. Because of the scarcity of documented records of its existence in New York State, U. minor was listed as a S2S3 (imperiled to rare in the state) species on the New York Natural Heritage Program Rare Plant Status List for 2003 (Young and Weldy, 2003). Intensive investigations that year involved search for plants in non-flowering condition and revealed that the species is much more common than previously thought. Its status was changed to S3 (rare in the state) for the 2004 list and it has been transferred from the “active” rare plant species list to the “watch” list (Young and Weldy, 2004).
A shrubby fen occupies a cove of the wetland south across the esker from the main poor fen. It is bounded on the south by Beaverdam Brook. Shrubs and small trees are quite dense in the northern (inland) portions of this area. The community becomes more open towards the south along the brook. In contrast to the level topography of the poor fen and the sedge meadow previously described, this shrub fen area presents a hummocky surface of a sort commonly found in other medium fens in the region.

A2: EXPLORING THE ROOT ZONE OF AN ANCIENT FAULT-DRIVEN HYDROTHERMAL SYSTEM IN THE ADIRONDACK LOWLANDS, NEW YORK
Bruce Selleck
Department of Geology
Colgate University
Hamilton, NY 13346
bselleck@mail.colgate.edu
ABSTRACT
This trip examines exposures in the Adirondack Lowlands that contain Paleozoic hydrothermal and fault related features hosted by Mesoproterozoic ‘Grenville’ marbles and Cambrian Potsdam Sandstone. These features have been the source of some debate historically and are now explicable as resulting from hydrothermal activity within an ancient wrench fault system. This system is similar to the deep structures that give rise to economically important gas and oil fields in the Appalachian Basin and elsewhere. The trip will include localities where the direct effects of coupled fault-related deformation and hydrothermal alteration can be seen, and the results of recent petrographic, stable isotope and fluid inclusion work will be used to better explain outcrop-scale features. The trip concludes with a stop in Ordovician Black River Group carbonates that demonstrates on a small scale the effects of hydrothermal dolomitization related to brittle deformation that may be linked to basement faulting. The regional extent, timing and tectonic significance of the fault systems will also be considered. INTRODUCTION The southern Canadian Shield of Ontario and the Adirondack periphery in northern New York State offer numerous exposures of the contact between high-grade metamorphic Mesoproterozoic basement and Cambrian Potsdam Sandstone. In some outcrops in this region the pre-Potsdam erosional topographic surface of the ‘Great Unconformity’ is exposed at small scale (Tiller and Selleck 1992). Higher order topography, particularly in the Adirondack Lowlands and Frontenac axis region, locally reflects Pleistocene and Holocene erosional unroofing of basement that has been underneath Paleozoic cover for 500 million years. While this region has been in general tectonically inactive during that time interval, insofar as major deformation of the Paleozoic rocks is not regionally evident, it is not surprising given that long interval of time that minor structural deformation and hydrothermal alteration has occurred. Faulting and gentle folding involving the basement and Paleozoic cover have been recognized in the Adirondack Lowlands (Barber and Bursnall 1978) and modern earthquake activity is a reminder of the ongoing brittle deformation of the crust at depths of 10 to 18 km in the region (Daneshfar and Benn 2002; Mitronovas 1985).
Hydrothermal alteration caused by fluids derived from the Paleozoic sedimentary sequence interacting with basement rocks immediately underlying Paleozoic cover is well-documented in southern Ontario and northern New York (Ziegler and Longstaffe 2000). This alteration has a distinctive spatial distribution related to fluid flow from the basal sandstone aquifer and presence of reactive rocks in the underlying basement. The mineralogical signature of this hydrothermal interaction includes a range of low temperature (300°C) phases that occur as vein and vug fills in both the basement and cover rocks, as authigenic phases in the sedimentary cover, and as distributed retrograde alteration of basement rocks. Mineral systems associated with this alteration include carbonates (dolomite, calcite, siderite, ankerite), phosphates (apatite, monazite, xenotime), sulfides (pyrite, galena, sphalerite), oxides (magnetite, hematite, anatase), phyllosilicates (kaolinite, illite, chlorite), and framework silicates (quartz, K-feldspar). This field trip will focus on the hydrothermal mineralization and alteration found in the marble belt region of the Adirondack Lowlands province. In the exposures we visit on this trip widespread dolomitization associated with Potsdam Sandstone erosional outliers and fault structures is the dominant type of basement alteration. This zone is interpreted as the structural root of an ancient hydrothermal dolomite (HTD) reservoir system. The overlying Paleozoic strata which hosted the HTD reservoir have been eroded away, but the fault-related features and hydrothermal mineralization of basement rocks and basal Potsdam Sandstone provide a window into the processes which give rise to these economically important systems which are well-known in a number of hydrocarbon provinces (Berger and Davies 1999). The timing of the coupled fault-hydrothermal activity is not well-constrained, but available data suggest activity could have occurred in medial-late Ordovician time coeval with the Taconic Orogeny or later in late Devonian time during the Acadian Orogeny.

A2: EXPLORING THE ROOT ZONE OF AN ANCIENT FAULT-DRIVEN HYDROTHERMAL SYSTEM IN THE ADIRONDACK LOWLANDS, NEW YORK

STOP 1. “Antwerp” granite syenite intruding marble
Outcrop on S side of Route 11 exposes “Antwerp” granite syenite intruding marble, which was followed by dynamothermal metamorphism producing upper amphibolite facies calcsilicate mineral assemblages, reaction boundaries between granitoid and marble, and deformation including boudinage, folding and fabric development. The high ductility contrast between the granitoid and marble results in disruption of original depositional and intrusive relationships. Paleozoic dolomitization of marble is evident along near vertical fractures and as diffuse zones extending away from fractures. An open fracture filled with dolomite-cemented sandstone is found on the top surface of the E end of outcrop. The old workings of the abandoned Sterling Mine, part of belt of hematite deposits found in this region (see text) are located on private property approximately 1 km SW of Stop 1.
The exposures on the N side of Route 11 contain brecciated and dolomitized marble, coarse dolomite and calcite spar and minor sulfide and quartz mineralization. Some calcite spar crystals are cored by deep brown or black calcite that contains abundant organic (petroleum) inclusions. The arrangement of dolomitized marble and void-filling minerals suggests multiple episodes of collapse brecciation and mineralization. Depending on the size of the group, we may visit the locality on the N side of the road when we return via same route.

STOP 2. Proterozoic marble with compositional bands
Low roadcuts on the SE side of Rt. 11 expose Proterozoic marble with cm- to dm-scale compositional bands defined by variations in abundance of graphite and calcsilicate minerals such as phlogopite and diopside. The banding dips gently to the SE. Vertical dolomitized zones are associated with joints that served, apparently, as conduits for dolomitizing fluids. The dolomitized zones are accentuated by minor weathering which imparts a brownish-tan or buff color to the dolomite in contrast to the white-blue-gray of the calcite marble. The contact between dolomitized and undolomitized marble represents a fluid alteration ‘front’ and minor hematite staining of partially dolomitized marble is present along this front. Note also the development of minor, millimeter-scale porosity in the dolomitized marble. The porosity is caused by the net reduction in solid volume during the 2CaCO3 + Mg2+ Ca,Mg(CO3)2 + Ca2+ reaction. Why are dolomitized limestones often good hydrocarbon reservoirs? Could a dolomitized marble like this serve as a reservoir rock?

STOP 3. Contact between Potsdam ss and Proterozoic basement
Roadcut on NYS Rt. 11 immediately NE of intersection with Richville Road exposes a fault contact between red-orange Potsdam Sandstone and Proterozoic basement. The Potsdam Sandstone here contains pebbles and small cobbles of quartzite, jasperite and cemented sandstone. Slickenlines on the E-W trending fault surface indicate reverse motion with Proterozoic marble moving up to the west over Cambrian Potsdam Sandstone. Note the dolomitization of calcite marble adjacent to fractures in basement rocks adjacent to the fault. The marble and calcsilicate rocks near the fault give way to the east along the roadcut to coarsely crystalline quartz-albite pegmatite. The exposures on the NW side of Rt. 11 will be examined as Stop 6 when we return via this route. Continue NE on Rt. 11

STOP 4. Near-horizontal beds of Potsdam Sandstone.
The exposure on the SE side of Rt. 11 consists of near-horizontal beds of Potsdam Sandstone. Depending on the condition of the road ditch at the NE end of the outcrop, a contact with Proterozoic marble is exposed. The basal Potsdam is locally a conglomerate, and near the base of the exposure cobbles of quartzite and jasperite are common. The upper portion of the exposure is medium sandstone. Note the irregular, disrupted lamination and cross-cutting color banding in the Potsdam. We will examine the exposures on the NW side of Rt. 11 as Stop 5.

STOP 5. Contacts between marble and Potsdam Sandstone
A series of outcrops on the NW side of Rt. 11 expose complex fault and hydrothermal solution collapse contacts between marble and Potsdam Sandstone. Proceeding from the NE end of the exposures, the first outcrop is comprised of intricately folded gray marble with a low-angle lineation marked by thin dolomite segregations. The folding of the marble is most likely the result of Proterozoic dynamothermal metamorphism but the dolomitic fabric may have resulting from strain during Paleozoic wrench faulting. Diffuse dolomitization of the marble, localized dolomitic halos around veins and dolomite + calcite void fills are also present. Continuing to the SW along the road, a fault contact between marble and a hydrothermal/fault breccia is poorly exposed near the end of the main marble outcrop. The breccia and adjacent deep red-brown sandstone here contains Potsdam sand grains and clasts of cemented sandstone, clasts of apatite-dolomite-quartz that represent rinds detached from hydrothermal pipe walls, spheroidal grains consisting of concentrically alternating hematite and siderite, and fragments of calcsilicate minerals including ‘bleached’ phlogopite; xenotime, tourmaline and monazite grains in the breccia have authigenic overgrowths. Complexly slumped or faulted sandstone adjacent to the contact is cemented by barite, pyrite and quartz. Mm to cm-scale arborescent masses of the Fe-sulfate jarosite (found by Opportunity on Mars) are present on rain-protected surfaces where pyrite is weathering. The outcrop on the SW end of the series of exposures consists of less disturbed and altered Potsdam Sandstone, resembling the lithology exposed across Rt.11 visited as stop 4.

STOP 6. (Opposite stop 3)
The lower portion of the NE outcrop at this stop consists of a hematite-stained fault gouge that grades progressively upward into more strongly layered and folded quartzite. The fault gouge consists of cm to meter scale blocks of quartz cemented sandstone and quartzite and deformed clasts of hematite-chlorite quartzite. The cleaved matrix consists of hematite-chlorite-illite quartz. Near the top of the exposure, the quartzite contains relatively unstrained layers of quartz-cemented sandstone with rounded grains. This outcrop is a relatively thick fault gouge zone associated with the Richville Shear Zone. The relatively resistant capping quartzite has prevented erosion and thus the weak fault gouge rock is exposed at the surface. Note the flattened, boudinaged quartzite fragments and the intense hematite staining. When the fault zone was active, material of this sort was flushed by reactive hydrothermal fluids.
The second major outcrop at this stop is directly opposite the fault exposure seen at Stop 3 across Rt. 11. The outcrop is somewhat unstable so use caution. Note the diffuse dolomitization of marble, large voids with dolomite, calcite and minor quartz and pyrite. Barite occurs in some void fills. Sparry dolomite and calcite alternate in some void fills, and tilted void floors apparently represent progressive rotation of voids as faulting and hydrothermal dissolution and mineralization occurred. Note the veins that crosscut former calcsilicate pods in altered marble and the residue of illite/chlorite and kaolinite which is left as a soft material on the void floors. Hematite staining and dolomitization is localized along fractures and become more pervasive as the fault surface is approached at the SW end of the exposure. The next stop is located on Rt. 11 approximately 0.2 mi SW.

STOP 7. Marble penetrated by hydrothermal pipes and tunnels
These exposures offer an excellent opportunity to examine marble penetrated by hydrothermal pipes and tunnels, the material filling these voids, and patterns of dolomitization and hematite staining of the marble altered by hydrothermal fluids. Note that some pipes (near-vertical orientation) represent solution-enlarged fractures, indicated by the lack of ‘fit’ of opposing walls. The pipe filling is typically Potsdam sand tightly cemented by hematite and quartz, with minor apatite. Barite, leucoxene, siderite and pyrite also occur as cements. Note that some pipes are filled with red-brown sandstone at the base but the upper portion of the pipe contains sparry dolomite, calcite and quartz as mineral precipitates. Tunnels (horizontal orientation) show a similar pattern of fill, and some show multiple sandstone-dolomite-quartz-calcite internal layering, representing multiple episodes of sluicing of unconsolidated sand followed by mineral precipitation. Some larger pipes and tunnels contain fragments of cemented sandstone and quartz-apatite-dolomite clasts interpreted as mineralized rinds spalled from the walls pipes and tunnels elsewhere in the hydrothermal system and carried by rapidly flowing hydrothermal fluids. The outcrop also displays a range of dolomitization patterns associated with the pipe and tunnel network and fractures. Note the ‘islands’ of undolomitized marble, and relict calcite ‘eyes’ in otherwise dolomitized rock. How can we reconcile the presence of hematite associated with reduced iron minerals, sometimes as concentrically alternating spheroidal grains? What is the origin of the pervasive hematite staining associated with the dolomitization of marble?

STOP 8.Upper portion of the Pamelia fm of the Black River Group
The outcrop on the NE side of Rt. 12 is in the upper portion of the Pamelia Formation of the Black River Group. The lithologies here include dolostone, dolomitic shale, lime mudstone, and wackestone. In general, these sedimentary facies represent deposition on a broad, relatively low-energy carbonate platform of Medial Ordovician age. This platform covered much of the interior of eastern Laurentia (North America) prior to the onset of subsidence and foreland basin development in later Medial Ordovician time. Key sedimentary features to observe are cryptalgal/microbial laminations, bentonite (volcanic ash) beds, mudcracks, evaporite (gypsum/anhydrite) mineral casts, and storm event beds represented by mud rip-ups clasts, intraclast breccias, stylolites and solution voids. The SE end of the outcrop is capped by a massive, tan weathering laminated dolostone. Immediately beneath the dolostone, beds of grey limestone are arrayed in a series of low, irregular folds with axes that trend N80W, approximately parallel to the highway. Thin (mm-cm thick) dolomite+calcite+pyrite+barite veins trending N70E are common in the limestone, and cm-scale calcite spar filled voids are present in the dolostone and some limestone beds. The mineralized fractures here are small-scale hydrothermal features that may be related to the dolomitization and related mineralization seen in the earlier stops on the trip. Note that the void fill minerals in the limestone beds are the same as those in the mineralized fractures. Examine the limestone - dolostone contact and see if you can trace mineralized fractures into the dolostone. Is the dolomitization here ‘early’ (preburial – related to Mg-rich brines derived from seawater that had precipitated gypsum) or is the dolomitization related to the later mineralized fractures? Why is some rock dolomitized whereas other rock remains nearly pure calcite limestone? Was there significant porosity in this rock at any time during its diagenetic history? Is the folding related to the minor mineralization or a later phenomenon?

A3: FRACTURES AND FAULTS IN THE EASTHERN LAKE ONTARIO BASIN, OSWEGO COUNTY, NY
Sabrina M. Stilwell
Jessica M. Gawron
David W. Valentino
Department of Earth Sciences
State University of New York at Oswego
Oswego, NY 13126
Joshua D. Valentino
23478 County Route 6
Mexico, New York 13114
INTRODUCTION
The central Appalachian basin is host to a number of regional joint sets associated with the late Paleozoic Alleghanian orogeny (Engelder, 1979; Engelder and Geiser, 1980; Evans et al., 1989; Zhao and Jacobi, 1997; Younes and Engelder, 1999; Engelder et al., 2001). A number of researchers demonstrated the orthogonal relationship between fracture sets and the trend of broad-open folds in the Paleozoic strata, and concluded that a major set are cross fold joints (Engelder and Geiser, 1980; Engelder, 1985). Cross fold joints are fractures that develop perpendicular to fold axes, and occur as non-parallel sets (Zhao and Jacobi, 1997) in the Appalachian basin of Pennsylvania and New York due to the arcuate shape of the orogen. Generally, the cross fold joints radiate perpendicular to the arcuate trend of the orogen. In central New York, the northern extent of the Appalachian basin, steeply dipping fractures that strike generally northwest are interpreted to be cross fold joints (Zhao and Jacobi, 1997). Development of these joints requires a component of orogen parallel tension. In a systematic study of regional joints, Engelder (1982) proposed a tie between specific joint sets and the contemporary stress within the lithosphere. This set of steeply dipping joints strikes generally east-northeast and were documented throughout the Appalachian basin from Ohio to central New York and it was proposed that they are related to the contemporary stress field (Engelder, 1982).
Along the southeastern shoreline of Lake Ontario (Figure 1) there are abundant outcrops of Ordovician Oswego Formation. As well, the eastern rivers within the basin are down-cut into the underlying Pulaski Formation forming excellent bedrock exposures in the Salmon River gorge (Figure 2). Both of these rock formations are dominated by clastic sedimentary rocks, are generally flat lying and contain a number of systematic joint sets. A recent study of these joints documented sets with orientations similar to the cross fold joints described above. Additionally, a set of east-northeast striking joints have evidence for sinistral shear including displacement of earlier joints and parallel zones of en-echelon fractures. During this field trip six locations will be visited to show the regional and local fracture sets in the Ordovician Oswego and Pulaski Formations in the eastern Lake Ontario basin, with special emphasis on evidence for sinistral shear.

A3: FRACTURES AND FAULTS IN THE EASTHERN LAKE ONTARIO BASIN, OSWEGO COUNTY, NY

STOP 1. Pavement outcrops of Oswego Formation
The shoreline of Lake Ontario at SUNY-Oswego has abundant outcrops of the Oswego Formation (see Figure 4 for the air photograph of this location). At this location, the Oswego Formation is a thick bedded green-gray sandstone (locally red) with minor siltstone and shale partings. Large cross beds and ripple marks are abundant. The fracture patterns described in the text can be seen at most outcrops, but this stop includes the pavement exposure located about 50 meters west of the westernmost metal staircase. This location contains abundant northwest and east-northeast striking joints, en echelon fracture zones, and one of the best exposed left lateral faults. See the text for details.

STOP 2. Fort Ontario, Oswego Formation
A large exposure of the Oswego Formation is located at the lake level below Fort Ontario. If time permits, you are encouraged to visit the historical Fort Ontario, which dates back to the French & Indian War and the War of 1812. The air photo below shows the location of the parking area, the outcrop and Fort Ontario. At this location, the Oswego Formation is again a thick bedded sandstone with abundant joints.

STOP 3. Ninemile Point, Lake Ontario.
From the parking area, follow the foot trail through the forest to Lake Ontario. The walk is about 1.2 km from the parking area to the place where the lake can be easily accessed. At lake level, carefully walk west to the outcrops that form a small cliff. At this location, the bedrock is interlayered sandstone, siltstone and shale, and the relative quantity of shale is more than at Stops 1 and 2. This outcrop is the lower part of the Oswego Formation, and may even represent the transition between the Oswego Formation and the underlying Pulaski Formation.
The attitude of joints at this location varies from the attitude at the previous stops. The rose diagram of Figure 13 shows a composite of 118 joints measured at this location. Fracture density measurements are represented on the detailed stratigraphic column of Figure 13, and show more fractures in the silty and shale portions of the outcrop.

STOP 4. Outcrop on the Salmon River
Under the railroad bridge east of Pulaski, NY
Once the parking area is reached, where the railroad intersects County Route 2A, walk west along the railroad to the bridge over the Salmon River. Do not enter the railroad tracks, or cross the railroad bridge. At the eastern side of the railroad bridge, carefully traverse down the slope to the river level. There is a steep trail on the south side of the railroad tracks. The outcrop is located north of the railroad bridge on the eastern side of the river. Although this exposure is deeply weathered, there are few easily accessible outcrops of Pulaski Formation. Here the formation comprises interlayered sanstone, siltstone and shale. Sandstone beds range from 0.5 to 1 m thick and the shale contains cm-thick beds of siltstone. Occasional tool marks, ripple marks, and flute-casts are present in the sandstone beds, and the shale beds contain fossils. Joints are best observed in the sandstone beds, and are dominated by a northeast striking set (Figure 13B).

Parking for stops 5 and 6
Follow the steep path (with stone stairs) into the Salmon River gorge. The path splits in two directions at the river level. Follow the river bank to the right (southwest) about 200 m to the waterfall.

STOP 5.
The series of outcrops that start at the waterfall and end at the sharp bend in the river downstream. At the river level, thick beds of sandstone comprise the lower part of the Pulaski Formation. Long joints (up to 30 m long), strike about 025 and are steeply dipping. These joints are spaces about 1-2 meters and intersect discontinuous joints that strike northwest (Figure 14A). The thick sandstone beds are overlain by interbedded sandstone, siltstone and shale that is progressively more dominated by fine grained sedimentary rocks upward. This sequence of rocks is best viewed in the cliff face that occurs in the sharp bend in the Salmon River. Walk back to the path and climb up the gorge. Follow the path eastward to the top of the Salmon River Falls. At this location, please obey all safety signs and stay in the designated areas.

STOP 6.
Pavement outcrop at the top of the falls of Oswego Formation. Here the rocks are green-gray sandstone with abundant ripples and large cross-beds. Joints transect the entire outcrop for many meters and occur in complex zones. The dominant joint set strikes about 060, but is associated with some complex joint patterns. In places the individual joints with an average strike of 035 curve and are continuous with the 055 striking joints. Additionally, there are en echelon fracture zones with apparent left lateral geometry that merge with the dominant joint set. Joint spacing varies from a few meters to well developed fracture zones with spacing less than 10 centimeters.

A4: CLASSIC LOCALITIES OF THE BLACK RIVER AND TRENTON GROUPS (UPPER ORDOVICIAN) IN THE BLACK RIVER VALLEY: REVISITED THROUGH TRADITIONAL AND SEQUENCE STRATIGRAPHY
Sean Cornell
Geology Department, St. Lawrence University
Joseph Andrews
Department of Education, LeMoyne College
Paul Agle
Department of Geology, State University of New York at Buffalo
David Thomas
Department of Earth Sciences, State University of New York at Oswego
INTRODUCTION
The late Ordovician (Mohawkian Series) Black River and Trenton groups of the northern New York State consist of some 250 m of highly fossiliferous, well-preserved limestones with some intervening shales. These rocks are exposed along a southeast-northwest trending outcrop belt for more than 250 km in central New York and neighboring Ontario, where they closely flank the Precambrian Grenville Province (Figure 1). These units deposited from ∼457-450 million years ago, have been studied for nearly two centuries and have become very important units for the study of paleontology, carbonate sedimentology, stratigraphy, paleoclimatology, paleoceanography, paleoecology, structural geology, and more recently, petroleum and natural gas geology. Mostly known from the renowned Mohawk Valley sections including those at Trenton Falls on West Canada Creek, the Black River and Trenton play (and have played) an important role in our understanding of depositional processes, environmental change and even mountain building and plate tectonics. The purpose of this field trip is to revisit the classic stratigraphy of the Black River and Trenton groups, and to introduce some of the modern research ideas that are being applied to answer long standing questions regarding the history of these rocks.

A4: CLASSIC LOCALITIES OF THE BLACK RIVER AND TRENTON GROUPS (UPPER ORDOVICIAN) IN THE BLACK RIVER VALLEY: REVISITED THROUGH TRADITIONAL AND SEQUENCE STRATIGRAPHY

STOP 1. Lowville, NY, Mill Creek Gorge
This locality represents the type locality for the Lowville Formation and although the original quarry section is flooded (it is just across the road from the gorge) the gorge offers excellent exposures and weathered outcrops for the review of sedimentary structures and fossiliferous strata. The section starts in the Pamelia Formation and intermittently in the banks at the lower end of the gorge. It is possible to observe the uppermost Pamelia Formation. Exposures of the “Depauville” Member and overlying Pittsburgh Quarry Bed of Conkin and Conkin (1991) can be identified.
Up in the narrows of the gorge, exposures of the lower Lowville Member or “Birdseye” of early workers can be seen in a series of well-developed meter-scale cycles, each with a flooding surface at their base and a shallowing upward motif. The Upper Lowville, or House Creek Member (of Walker, 1973), is fairly well exposed in the southern wall of the gorge and although it can be difficult to access, this member of the Lowville is distinctively less argillaceous and more massively bedded. It is composed almost exclusively of bioturbated wackestones with minor stringers of intraclastic packstones, and a few ribbon bedded horizons showing some ooid development. Overall the House Creek represents protected, but marine conditions typical of shallow water lagoon areas. Although it is much more subtle and is occasionally recognized as one more cycle of the Lowville, the uppermost beds of the House Creek, or the “Weaver Road Beds” show the distinctive development of domal stromatolites in fairly argillaceous platy micrites. Overlying the Lowville Formation is a series of more massive-bedded limestones previously referred to the Watertown Limestone. Although much of this particular interval is extremely cherty, the basal few feet are less so and are fairly coarse-grained. In stark contrast to the underlying lithologies, the basal few feet of the upper massive unit are characterized by large colonies of Tetradium, crinoids, brachiopods, a variety of high-spired gastropods and numerous other taxa. Given the faunal and lithologic composition of this bed and through correlations with sections to the northwest in the Watertown area, it is believed that this thin interval of beds represents what is left of the Leray-Glenburnie interval. Without the occurrence of the Hounsfield K-bentonite (sensu Kay, 1931), in this succession it is surmised that the Glenburnie and the K-bentonite have been eroded by the overlying sequence boundary and were removed prior to the deposition of the Watertown. The Watertown is the last well-displayed unit is this portion of Mill Creek. Just below the Rt. 12-26 bridge over Mill Creek, the south wall of the gorge displays the massively bedded and chert-rich equivalent of the Watertown Limestone. Approximately 4 m of Watertown are exposed and are typically well bioturbated wackestone to packstone facies. Like the House Creek, the Watertown contains many coral taxa, sponges and stromatoporoids, and more diverse brachiopod and crinoid assemblages. Based both on lithologic and faunal patterns, the Watertown itself demonstrates a significant and even more substantial upward deepening pattern. Although many of the internal cycles have become amalgamated, they can often be identified through the recognition of firmground and hardground surfaces. These surfaces become especially prominent near the top of the succession where they show evidence for phosphate, pyrite, glauconitic staining, and may even contain K-bentonites sitting on them. Moreover, these surfaces often are accentuated by hard-substrate borings and in some instances have been found to contain crinoid & bryozoan holdfasts indicating that these surfaces were well cemented on the sea-floor prior to their final burial. Collectively then, the Watertown itself is clearly an upward deepening unit and although it does not represent the deepest portion of the sequence, it is the deepest facies within the entire Black River to this point.
Near the top of the gorge section below the bridge, a small poorly-exposed succession of rubbly weathering wackestone-packstone lithology stands in stark contrast to the underlying massive bioturbated beds of the Watertown. This particular interval becomes very condensed in places and shows evidence for sediment starvation through the accumulation of numerous current aligned cephalopods (with a variety of taphonomic signatures), and a range of diminutive orthid, and strophomenid brachiopods (Dalmanella, Sowerbyella respectively). This unit is referred to as the Selby, and is included in the Rocklandian Stage. Lithologically and faunally, the Selby is transitional out of the Watertown into the overlying Napanee Formation. Unfortunately, poor exposures above the bridge do not permit the observation of the upper Selby to Napanee interval.

Parking for stops 2a and 2b

STOP 2a: East Martinsburg, NY
ROARING BROOK, LOWER SECTION Just east of Route 12 on the lower section of Roaring Brook is the unconformable contact of the Pamelia Formation with the underlying Precambrian Grenville Gneiss. Although exposure here is covered for some distance above the contact, a few feet of the Pamelia are exposed and document the transition from a siliciclastic sandy (dominated by quartz and feldspar fragments) carbonate upward into more medium-bedded argillaceous limestones. Although very few fossils are found in this unit, occasionally a few gastropods, ostracods, and small fragments of bryozoans are represented. These are commonly of poor preservational style and many are coated with greenish glauconitic material. Although the depositional history of this lowermost Pamelia is not well constrained, it is very similar to strata exposed in southeastern Ontario where this particular interval is located on the top of the Shadow Lake and is time equivalent with the basal Gull River Formation. Here in New York, the basal Pamelia sandy limestones are thought to represent the deepest phase of the Shadow Lake or Rideau sequence and overall remain fairly shallow but mudcracks a few feet off the basal sands suggest that this may be a shallowing succession off the basal transgressive surface. That is the red and green shaly carbonates of the Shadow Lake (which are not developed here in the central Black River Valley) were probably deposited during the transgressive phase, while the overlying lower Pamelia was deposited during the maximum inundation of that particular sea level rise event.

STOP 2b. East Martinsburg, NY, Roaring Brook
MIDDLE SECTION Up section, the remainder of the Black River Group is exposed through the top of the Watertown Limestone. The middle-upper division of the Pamelia is well represented and overall represents one transgressive-regressive sequence. Although not formally named, the middle or “Thompson Farm” member is a distinctive facies of the Pamelia and is well developed through the transition from laminated argillaceous micrites and dolomicrites to more medium-bedded (and distinctively less argillaceous) wackestones containing a fairly restricted fauna but occasionally contains a few echinoderm fossils (crinoids), a few large strophomenid brachiopods, very large endoceratid cephalopods, and several trilobite taxa. In contrast to the more restricted ostracod-bivalve-gastropod assemblages of both the lower and upper Pamelia, the middle member is characteristically more normal marine in faunal composition. Although it is still considered a fairly shallow peritidal deposit, the presence of these faunal elements indicates that the middle Pamelia was deposited in deeper water. A fairly rapid and substantial transition upward into the upper Pamelia or “Depauville Waterlime” of early workers is documented by the transition back into dolomitic limestones and sandy dolomites characteristic of this interval. In addition, distinctive sedimentary features suggest that this particular interval shows evidence of hypersaline conditions. In some beds evaporite crystal pseudomorphs are distinguished as are the development of large vugs containing celestite and/or gypsum. Although it is clear that many of these have been recrystallized during later diagenesis, the moldic preservation of some of these crystal faces indicates that these environs may have been highly saline at the time of deposition.
Above the Pamelia, both the lower and upper Lowville members are well exposed and with some investigation are readily compared to sections visited at Mill Creek in Lowville. Unfortunately, due to extreme solution along joints in the stream bed, many of the sedimentary and faunal details of the Lowville are obscured but many are still readily observable. In this region, the Lowville is approximately 25 m thick. Near the top of the succession, an argillaceous, mud-cracked interval at the base of the Watertown is recognized. Although there are no large domal stromatolites (as in the northern Black River Valley), there is evidence for low, broad stromatolitic mounds (LLH style) in this interval. These stromatolites border on thrombolitic textures where they are burrowed and are evidently grazed.
Continuing upstream are exposures of the Watertown Limestone. Again as below, some local small-scale structures are developed in these exposures. Although most appear to be related to differential compaction over shallow Precambrian basement features, it is also evident in this section that there are minor faults that offset strata locally. It is not clear at this time if these are related to more recent uplift associated with Neogene to recent Adirondack tilting or if these are representative of local faulting at or near the time of deposition in the Upper Ordovician. Nonetheless, the Watertown and overlying Selby Formation represent a continuous deepening showing the upward transition from typical bioturbated cherty wackestones and packstones of the upper Watertown into more nodular, rubbly weathering Selby. The Watertown itself is substantially thinner than the Watertown in the type region and it is believed that only the upper portion of the Watertown is here by overlap. At the top of the section, as is the case in most of the region, the top Selby forms a broad terrace where the overlying shaly bedded Napanee Formation is eroded back almost a half mile. Although we will not trek overland to the next exposure, the basal beds of the Napanee are intermittently exposed just upstream.

STOP 3. Whitaker Falls Park, Martinsburg, NY
ROARING BROOK UPPER SECTION Upstream from the previous stop, we start just above the lower waterfall in Whitaker Falls. Although we could travel downstream, for the sake of time, we will focus on the interval from the lower falls upward through the upper Trenton. This portion of Roaring Brook exposes the entirety of the Shermanian from the Sugar River at the base through the Denley, Rust, and finally the Steuben formations. We will not see the Kings Falls or Napanee up close at this locality although they are exposed downstream (we will see them at the STOP 4 in Boonville, NY). Exposed in Whitaker Falls Park are three closely spaced waterfalls in this portion of the gorge. Just below the lip of the first waterfall, and exposed in the south wall of the gorge are the uppermost beds of the Kings Falls (forming the floor below the falls) and the Lower Sugar River formation. The shaly nature of the Lower Sugar River allows for it to be slightly less resistant and allows for the notch under the waterfall. Also exposed in the wall of the gorge at this point are at least two recessive weathering notches and a deformed channel. The channel and the layer above the waterfall show evidence for brecciated fabrics suggesting syn-sedimentary movement of materials on the sea-floor after some period of lithification. Although it is not yet clear as to the regional relationship of this feature, both of these features are found in many local sections throughout the region and are prominent horizons useful for correlation.
The lowermost waterfall is capped by the Rathbun Member of the Sugar River Formation and near the top of the middle waterfall is the transition to the upper Poland. Just above the lip of the middle falls and below the bench leading to the upper waterfall is the transition to the Upper Denley (Russia Member). Within the face of the third falls are the well developed cycles of the Russia and the basal Mill Dam Member of the Rust Formation. The fairly coarse cycle caps of the Mill Dam help to hold up the face of the falls and are exposed for some distance upstream where excellent large-scale ripples are well developed on them. Like the coarse-grained Kings Falls some distance downstream, the Mill Dam in this region was substantially shallower than the underlying Denley Formation, although it too shows an upward deepening pattern.
Continuing upstream some distance exposures in the wall of the gorge afford views of the Rust Formation and its members. In the walls of the gorge before the Glendale Road Bridge, exposures of the Mill Dam and Spillway members show characteristic coarser-grained facies with well preserved faunas, extremely large brachiopods and some crinoids. Another deformed interval is located here and is tentatively correlated with the uppermost Spillway member slump structure at Trenton Falls. Just above the bridge, exposures of the Prospect Quarry member give way to the basal coarse-grained Steuben Formation. Although an additional 25-30 meters of section are exposed upstream near the Martinsburg town garage (as is the contact with the overlying black shales), owing to time constraints we will defer their investigation at this time.

STOP 4. Boonville NY
BARRETT MATERIALS AND PAVING QUARRY AND SUGAR RIVER SECTIONS
Just north of the village of Boonville, NY on the north shore of Sugar River sections are exposed in the Barrett Materials and Paving Quarry and in the adjacent stream section to the south of the quarry and along route 12. Entrance is by permission only and hard hats and steel-toed shoes must be worn at all times. Although exposures in this section extend down to the base of the Pamelia, we will focus on the uppermost Black River Group exposed in the quarry. In the older northwest corner of the pit and along the west wall of the pit, exposures start in the lower Lowville and extend upward through an abbreviated House Creek section where the Watertown Limestone, or “7’ tier” of quarry operators, immediately overlies the middle House Creek with possible unconformity. Although the 7’ tier is dominantly a single massive bed composed of fairly coarse micritic wackestone, in the face of the unit to the southwestern corner of the pit, the upper massive bed displays a prominent recessive notch containing a prominent clay horizon. Although it still remains to be chemically fingerprinted it sits in the same position as a K-bentonite approximately 1.5 meters below the top of the Watertown at Brownville gorge. In the older portions of the quarry, the K-bentonite has been squeezed out and it is difficult to make out, as is the case in most of the weathered stream sections.
Although no higher exposures are afforded in the quarry–the cap of the quarry wall is the Watertown– additional exposures in the stream bed allow for the continuation of the stratigraphic section. Just to the south of the quarry in the stream bed and southern bank of the Sugar River, the upper contact of the Watertown with the Selby is observed. The massive Watertown is easily recognized in the bed of the stream and along the southern bank a several decimeters of thin-bedded rubbly weathering limestone is exposed below the typical shaly-interbedded Napanee Formation. At this particular location, only the basal 2-3m of the Napanee is exposed in the outer bend of the stream. Upstream, above the NY 12 bridge, additional sections are exposed from the Napanee up through the King Falls Formation. W will not walk upstream to see them in weathered section, but we will look at the same interval in the road cuts on both the north and southwest side of the highway. Here in the road cuts are the uppermost ∼5 meters of Napanee followed by ∼3 meters of Kings Falls. Although not in the best position for weathering, the outcrop shows the sharp contact of the Kings Falls on the underlying Napanee. In fact, the contact shows evidence for channeling into the underlying Napanee at the M5A-M5B sequence boundary. Additional exposures are visible upstream, including the type succession of the Sugar River Formation, and additional units up through the upper Trenton.

B1: CLASSIC LOCALITIES OF THE BLACK RIVER AND TRENTON GROUPS (UPPER ORDOVICIAN) IN THE BLACK RIVER VALLEY: REVISITED THROUGH TRADITIONAL AND SEQUENCE STRATIGRAPHY (Part II)
Sean Cornell
Geology Department, St. Lawrence University
Joseph Andrews
Department of Education, LeMoyne College
Paul Agle
Department of Geology, State University of New York at Buffalo
David Thomas
Department of Earth Sciences, State University of New York at Oswego
The late Ordovician (Mohawkian Series) Black River and Trenton groups of the northern New York State consist of some 250 m of highly fossiliferous, well-preserved limestones with some intervening shales. These rocks are exposed along a southeast-northwest trending outcrop belt for more than 250 km in central New York and neighboring Ontario, where they closely flank the Precambrian Grenville Province (Figure 1). These units deposited from ∼457-450 million years ago, have been studied for nearly two centuries and have become very important units for the study of paleontology, carbonate sedimentology, stratigraphy, paleoclimatology, paleoceanography, paleoecology, structural geology, and more recently, petroleum and natural gas geology. Mostly known from the renowned Mohawk Valley sections including those at Trenton Falls on West Canada Creek, the Black River and Trenton play (and have played) an important role in our understanding of depositional processes, environmental change and even mountain building and plate tectonics. The purpose of this field trip is to revisit the classic stratigraphy of the Black River and Trenton groups, and to introduce some of the modern research ideas that are being applied to answer long standing questions regarding the history of these rocks.

B1: CLASSIC LOCALITIES OF THE BLACK RIVER AND TRENTON GROUPS (UPPER ORDOVICIAN) IN THE BLACK RIVER VALLEY: REVISITED THROUGH TRADITIONAL AND SEQUENCE STRATIGRAPHY (Part II)

STOP 1. Depauville, NY, Roadcut On NY12
The village of Depauville contains an excellent succession of the Black River Group and the contact of the basal Pamelia with the underlying Theresa Formation (Upper Cambrian). The Pamelia is mostly exposed in the waterfall succession of the Chaumont River (and just to the west along Buttermilk Creek) where nearly 9m of Pamelia are exposed below the county route 170 (Depauville Road) bridge. We will not look at this succession and instead we will focus on the relatively new outcrop on the northern limits of the village along NY 12. Just above the Depauville VillageMarket, and below the town garage, a fairly long stratigraphic succession of nearly 20m is visible along both sides of the roadcut. We will use this section to discuss the long-standing debate concerning the description of the Pamelia-Lowville contact. In previous classifications the contact was drawn either at the highest dolomitic limestone or at the lowest occurrence of relatively pure “birdseye.” In this locality a prominent succession of cyclically-bedded limestones shows an upward deepening pattern and is based at a very distinctive quartz-rich sandy bed. This bed, referred to as the Pittsburgh Quarry Bed by Conkin and Conkin (1991), is a prominent marker from southern Black River region through southwestern Ontario and even in the Ottawa region. Given the prominence of this marker and the very distinctive pattern of cyclically-bedded carbonates above, an argument can be made for placing the upper contact at this stratigraphic position, thus including it in the base of the Lowville Formation. Although some dolomitic limestones do occur above this position, they are few and dominated by the relatively pure micrites of the Lowville. The remainder of the succession through the cap of the outcrop is referred to the lower member of the Lowville Formation and shows the overall transgressive pattern of the M4 sequence. Near the top of the succession a noticeable reentrant occurs and contains a K-bentonite which correlates with a prominent K-bentonite in Ontario referred to as the MH K-bentonite. The recognition of this reentrant is aided by its position just below the sharp flooding surface to the overlying House Creek Member. The terrace at the top of the outcrop is developed in the basal House Creek with the remainder of the House Creek exposed in the bluffs to the north, west, and south of the village.

STOP 2. Limerick, NY, Roadcut On Rte 180
JUST EAST OF GUFFINS CREEK This stop is intended for quick look at facies of the upper Lowville House Creek that have not been observed up to this point. In the small outcrop on the northwest side of the road, a succession of ∼4-5 meters of strata are exposed. The base of the succession is dominated by bioturbated wackestones containing various algae, corals, and a variety of brachiopods, the House Creek is clearly more normal marine than any of the underlying units in the Black River. Nearer the top of the section, relatively coarse-grained facies are developed and in places show evidence of cross-bedding and ooids. Intermixed with Stromatocerium stromatoporoids, the ooids reflect an important shift in the deposition of the House Creek suggesting a shallowing which is terminated in the Weaver Road beds (observed at STOP 3).

STOP 3. Brownville, NY, Roadcut on Rte 54
NEAR BROWNVILLE FISH-GAME CLUB It is unfortunate that the type section of Kay’s Hounsfield K-bentonites (sensu 1931 and 1935; see Stop 4) is overgrown and poorly exposed. To alleviate this difficulty this newly widened outcrop section located on the northeast side of Rte 54 just NW of the intersection with Mullin Road, is used as a new reference section for the uppermost Lowville through basal Trenton succession. This outcrop displays the Weaver Road beds at the base of the outcrop, the overlying Leray and Glenburnie interval and the overlying Watertown Formation. In this particular succession, K-bentonites are located at several horizons, including near the base of the Glenburnie (Hounsfield sensu Kay, 1931) and in the overlying Watertown near the base of the Selby (sensu Kay, 1935). The stratigraphic succession shows evidence for mud-cracked argillaceous ribbon micrites sharply overlain by the somewhat sandy and coarse-grained basal Leray. The Leray in this succession is relatively thin (∼1.5m) and is overlain by the rubbly weathering Glenburnie. This particular facies is very subtle in relationship to the Watertown and is most often included within it. However, as this unit is traced into southern Ontario, the Glenburnie interval becomes distinctively more shale rich and equates to a 1.5 m thick shale in the Kingston region located below the much coarser grained and cross-bedded Watertown in that region. In New York, the Watertown is less of a grainstone, but is dominated by extremely bioturbated wackestone-packstone facies. The remainder of the succession displays the cherty facies of the Watertown that generally is developed along bedding planes and within burrows. The Watertown becomes distinctively more nodular towards its top and at the position of a prominent reentrant the facies changes to a much more condensed and darker grey, rubbly weathering unit referred to as the Selby. Only a minor portion of the Selby is exposed, as it and the overlying Napanee Formation were relatively nonresistant to glacial processes that were active in this region.

STOP 4. Brownville, NY, Farr’s Quarry
AND ROADCUT ON WEST SIDE OF GAME FARM ROAD
As mentioned at STOP 3, the original type-section for Kay’s Hounsfield K-bentonites is poorly exposed, and despite a covered interval in the quarry and adjacent lower ditch, the stratigraphic succession continues up the hill through the Napanee and into the lowermost Kings Falls Formation which forms the cap of the hill below the junk yard. This stratigraphic section is visited to continue and to illustrate the relatively close stratigraphic proximity of the new Fish-Game Club locality just northwest of here (STOP 3). Although the contact of the Selby and Napanee is poorly exposed during late winter and early spring it is possible to get near the base of the Napanee to measure and describe ∼8-9m of section. In this region, the Napanee is fairly fossiliferous and contains several identifiable taxa including many key brachiopods, some crinoids, and several trilobites. Overall, the Napanee is defined as interbedded shales, calcisiltites, and thin-bedded wackestones. Nearer the top of the ditch the Napanee begins to shallow upward showing more thin-bedded coquinal packstones and grainstones. The base of the overlying Kings Falls is represented by the very sharp contact to the medium-bedded and rippled grainstones of the Kings Falls.

STOP 5. Glen Park, NY, Black River Gorge
In the recent past, the Black River Gorge has become synonymous with rafting/kayaking and hydropower. In the narrow part of the gorge, from just below Brownville village through the parking area just above the hydroplant diversion channel, the Black River Gorge descends through about 25m of section ranging from the Lower Lowville at the western end of the gorge through the Selby at the eastern end. On the opposite or south side of the river, exposures of the overlying Napanee are exposed intermittently in the bluff. Although we saw the same succession at STOP 3, the exposures here in the gorge afford an excellent opportunity to look at well-weathered blocks and enigmatic structural features that indicate there may be some offset between the two sides of the river. Below the fish ladder (accessed via the gravel road that runs along the edge of the water diversion channel) it is possible to observe the beautifully exposed Weaver Road Beds. If water level is low enough, we will walk on them and study their complex structures. The field trip will “officially’ end here; however, interested people may wish to continue on to outcrops at King’s Falls.

STOP 6. Copenhagen, NY, King’s Falls on Deer River
Like many localities in this region, the Deer River is characterized by several well-developed waterfall successions. Among them are the beautiful sections at Kings Falls just north of the Village of Deer River on NY 26. Accessed via Old State Road, this succession begins in the upper portion of the Napanee and continues upstream to the summit of Kings Falls which exposes the upper Sugar River and basal Denley (Denmark of Kay for the region just south of this locality). Several fascinating structures are found at this locality. In contrast to the block-faulted regions of the Mohawk Valley, the Tug Hill Plateau is often considered as a tectonically quiescent carbonate platform during deposition of the Trenton. This stop, in addition to the section along Roaring Brook with the S-fold below the lower falls, and the brecciated horizons, as well as the structures at the Glen Park section, shows that this region may not have been so stable. Much interest has recently been generated in Trenton/Black River structures due to recent natural gas exploration in the Finger Lakes Region of New York State. The producing horizons are in dolomitized graben where hydrothermal fluids have migrated along the bounding faults. While, the fault kinematics and mineralization is different here at King’s Falls, it does appear that they have acted as fluid conduits. Beneath the Old State Road bridge are excellent exposures of basal King’s Falls with thick-bedded calcarenites and grainstones, some showing large symmetric ripples. Downstream the lower contact with the Napanee Formation is exposed. Where the river turns to the west the beds on the north side are dipping towards the northeast, while the beds on the south side have experienced minor faulting. A small thrust fault ramps up towards the east with drag folding of the footwall. Just downstream of this thrust is a small (offset ∼0.2m) NNE-trending normal fault with rollover folding on the hanging wall. While these structures are minor, there is significant mineralization in the outcrop including thick calcite veins, an ironrich or possibly sulphide residue on joint surfaces, and significant dissolution of brachiopods in certain beds. This evidence indicates that these faults have acted as fluid conduits. Farther upstream at the base of King’s Falls is another fault. This fault strikes roughly east-west, dipping 40ºS with the beds of the hanging wall drag-folded into the fault trace. The hanging wall is composed entirely of the King’s Falls Formation. There is also significant mineralization near this fault in the form of thick veins and rare vugs. The King’s Falls-Sugar River contact is exposed about halfway up the falls.

B2: VARIATIONS IN L- AND S-TECTONITE ON THE NORTHERN BOUNARY OF THE PISECO LAKE SHEAR ZONE, ADIRONDACK MOUNTAINS, NY
Damian Piaschyk
Department of Geology and Planetary Science
University of Pittsburgh
Pittsburgh, PA 15260
David Valentino
Department of Earth Sciences
State University of New York at Oswego
Oswego, NY 131263
Gary Solar
State University of New York
College at Buffalo
Buffalo, NY 14222
Jeffrey R. Chiarenzelli
Department of Geology
State University of New York at Potsdam
Potsdam, NY 13676
The subject of this field trip is the variation in deformation fabrics along the northern margin of the Piseco Lake shear zone (Gates et al., 2004) with special emphasis on the development of L-tectonite domains at various scales. To some extent, but on a much more regional scale, this was also the emphasis of field guide for the 76th NYSGA field conference (Valentino et al., 2004). The current field guide covers a geology field trip that is a continuation of the earlier field trip with overlap of a few field stops.
The Piseco Lake shear zone (Figure 1) is a major Grenvillian structure that is 10 to 20 kilometers wide and strikes generally east -west in the southern Adirondacks. Kinematic analysis in the zone demonstrated dominantly low-angle sinistral shear (Gates et al., 2004). For the current study, an area of 42 square kilometers was mapped in detail and the study area spans the northern limit of the Piseco Lake zone in the area of the West Canada Creek basin (Figures 1 & 2). The objective of this study was to document the detailed rock fabric variation within the shear zone, within the transition zone and within the wall rocks to the shear zone. This study was designed to better understand the strain and metamorphic history associated with this major Adirondack structure, and document the geographic distribution of L- and L-S tectonites that were previously reported (McLelland, 1984; Chiarenzelli et al., 2000; Gates et al., 2004).

B2: VARIATIONS IN L- AND S-TECTONITE ON THE NORTHERN BOUNARY OF THE PISECO LAKE SHEAR ZONE, ADIRONDACK MOUNTAINS, NY

STOP 1. S>L Granitic gneiss with strong gneissic texture
Exposures of course granitic gneiss with well developed gneissocity can be seen in the high-wall of this old quarry. This stop demonstrates S>L fabric, lineation area weakly developed and foliation dominates. (Figure 5). The grain size is uniform and few kinematic indicators are present. The foliation is penetrative and is defined by planes of K-feldspar and biotite and dips to the northwest. The lineations are defined by streaks of biotite and plunge to the southwest.

STOP 2. L-S and S>L Dioritic Gneiss
The southern most part of the outcrop demonstrates L-S fabric (Figure 6). Lineations are about equal to foliation in intensity. Rods of hornblende define the linear fabric, which plunges to the southwest. Plagioclase and quartz define the foliation. In thin sections of this outcrop a ceased reaction is preserved. The hornblende crystals were breaking down to form biotite in a retrograde reaction. The northern most part of the outcrop demonstrates S>L fabric with gneissic textures, similar to the previous stop. Some small faults with 15cm of displacement and boudins are also preserved at the northern end of the outcrop (Figure 6). Garnets are also visible at the northern end of the outcrop but were not observed at the southern end in hand sample or thin section.

STOP 3A. East of the Ohio Gorge.
The West Canada Creek forms a small waterfall at the upstream part of this outcrop. Pavement exposures reveal the L-S and L>S deformation fabric in granitic gneiss (Figure 7). Foliation is gently dipping and the lineations are subhorizontal. In the region immediately down-stream of the falls, the foliation is defined by planar aggregates of recrystallized K-feldspar and quartz that alternate with dark layers containing abundant chlorite and minor biotite. The dominant fabrics are cross cut by at least three small high-strain zones. Two are steeply dipping and strike about east-west, and the third strikes south and dips moderately westward. One of the steeply dipping high-strain zones occurs in the vertical face at the southern side of the outcrop. Another occurs at the western limit of the outcrop close to the water. The north-south striking zone occurs in the low ledge near the falls. This small shear zone contains deformed pegmatite, and cross cuts the Piseco Lake shear zone foliation and lineation. Shear sense is top down to the west or normal. The other high-strain zones both contain evidence for oblique sinistral shear.

STOP 3B. East end of the Ohio Gorge.
The east end of the Ohio gorge demonstrates L>>S and L-S fabrics. The gorge contains granitic gneiss that varies only in the proportion of quartz, K-feldspar, plagioclase, biotite, and chlorite. The L-S domains have the larges grain size with numerous δ and σ shear sense indicators. The L-S domains also demonstrate lineation about 1 to 5 cm long, .5-2 cm wide, and 1-3 lineations per cm. The L>S domains have a smaller grain size then the L-S domains. The L>S domains demonstrate more lineations and less shear sense indicators, lineations are 1-6 cm long, .5-2 cm wide, and 3-5 lineations per cm. A contact between L>S and L-S can be observed (Figure 8). West of the fabric contact is an oblique left normal fault about 5 cm wide. This fault crosscuts the metamorphic fabrics strikes north south and dips to the east. Farther west is a .5 m wide pegmatite that strikes northwest southeast and dips southwest that also crosscuts metamorphic fabric. The pegmatite is composed of quartz, K-feldspar, and minor chlorite with grains about 1 to 3 cm in size.

STOP 3C. West end of the Ohio Gorge.
Stop 3C requires a .75-kilometer traverse west along the ridge of the Ohio gorge. Please WATCH YOUR STEP because the walls of the gorge are vertical and a fall would likely result in serious injury or worse.
The west end of the Ohio gorge also demonstrates L>S and L-S domains. Another ductile normal fault can also be observed. The ductile normal fault is much larger then the one observed at the east end of the gorge (Figure 9).

STOP 4A. L>>S Granitic Gneiss
Excellent outcrops on the northern side of a small hill just east of the parking area. Follow the dirt road to a path through the woods, and then head up hill to the south to the outcrops. This outcrop of granitic gneiss contains domains of L>S and L>>S. The L>S domains contain large and numerous σ-type shear sense indicators, some δ-type are present but are much less frequent. The porphyroclasts are large about 1-3 cm and the recrystallized porphyroclastic material is often wrapped with a quartz ribbons (Figure 10). The interpreted shear sense is low-angle and left lateral. The granitic gneiss is composed of quartz, K-feldspar plagioclase, and minor chlorite and biotite. The foliation strikes east west and dips to the south.

STOP 4B. Mafic Gneiss and L>>S Cigar Shaped Domain
This stop requires about 2.5 kilometers of traverse at a bearing of about 280º. The traverse will cross a few small streams and under brush can be thick in places. There is no trail to follow, so PLEASE STAY WITH THE GROUP.
Mafic Gneiss. This outcrop is a rare mafic gneiss composed of biotite, hypersthene, plagioclase, quartz and ilmenite. The fabric is L>S, lineations are defined by rods of plagioclase and streaks of biotite. The grains size is very small about 0.5mm. This rock unit borders the L>>S domain which can be seen at the next outcrop.
L>>S Cigar-Shaped Domain. The final stop is a spectacular L-tectonite (Figure 11). The outcrop is granitic gneiss composed of quartz, K-feldspar, plagioclase, and fabric forming chlorite and biotite. Foliation is hard to see in hand sample but can be seen if stained for plagioclase and K-feldspar. Figure 11 – Rock sample from STOP 4C with three mutually perpendicular cuts to reveal the internal fabric. Quartz rods and recrystallized aggregates of K-feldspar define the penetrative lineations, and foliation does not exist in this specimen. The dark minerals are primarily chlorite and biotite, and they too define a microscopic lineation as demonstrated by Price et al. (2003).

B3: MONITORING COASTAL CHANGE: EASTERN LAKE ONTARIO
Sharon L. Gabel
Robert Venczel
Department of Earth Sciences
State University of New York
Oswego
John Dehollander
Oswego County Soil Water Conservation District
David White
New York Sea Grant
Oswego, NY
This field trip will examine the sandy beach-dune barrier system that extends for nearly 17 miles north of the Salmon River mouth along the eastern Lake Ontario coast (Fig. 1). Barrier bars separate ponds and wetlands from open waters of Lake Ontario and are cut by inlets that connect ponds to Lake Ontario. The sandy beaches and dunes on the barrier system, together with adjacent wetlands, ponds and lake waters, provides habitat for a number of rare plant and animal species and also for fish, waterfowl and migratory birds. The beaches also afford recreational opportunities for residents and tourists, and inlets provide access to Lake Ontario for recreational craft from marinas and boat launches around ponds and tributary streams. The sand dunes here are the largest in the state, and they protect residences landward of the dunes from wind and wave erosion and flooding due to storm surge. The shoreline is a mix of public and privately-owned land, with public lands designated as state parks and wildlife management areas. The private land that amounts to roughly half the barrier system has been developed for cottages, homes, RV parks and campgrounds that are built on or just behind the dunes. Governmental and non-governmental conservation agencies have been working for decades to protect this fragile system.
A program of beach profiling has been ongoing since 2002 at 5 locations in the barrier system (Fig. 2). The goal is to identify patterns of seasonal and longer-term erosion and deposition on these beaches. This field trip will visit several locations where beach monitoring has been conducted. Since 2003, Sandy Pond Inlet has been studied by detailed mapping. This inlet is a very important access point to the lake from the numerous marinas and private residences around North Pond. The inlet becomes shallow in late summer, and larger craft have difficulty navigating the shallow channel. We will visit Sandy Pond Inlet at the end of this field trip.

B3: MONITORING COASTAL CHANGE: EASTERN LAKE ONTARIO

STOP 1. Black Pond Wildlife Management Area
We will walk from the parking lot along the boardwalk that takes us through the wetland adjacent to Black Pond onto the barrier. Note the tall dunes at this location. The boardwalk takes us over the dunes to the beach. At this location we will examine the wetland and pond environments of the barrier system as well as the beach and dunes. Zebra mussel and quagga mussel shells are abundant here, particularly in the spring or after storms. A short hike on the beach to the north will take us to the inlet that connects Black Pond with Lake Ontario.

STOP 2. Southwick Beach State Park picnic area adjacent to beach.
We will walk along the beach to our beach profiling locality. Here we can observe some of the efforts that have been made to reduce human impacts on the beach and dunes. This will also be our lunch stop.

STOP 3. Deer Creek Marsh (grass parking lot)
A short trail will lead us to an viewing platform overlooking Deer Creek Marsh where we can discuss some of the human impacts on coastal wetlands. We will then proceed to the cobble beach.

STOP 4. Sandy Island Beach State Park
Sandy Island Beach is the location of another beach profiling transect. We will discuss the many changes in management this beach has undergone over the decades. Tremendous efforts have been made by government agencies and conservation groups to improve conditions at this beach. One such effort involved moving a vast quantity of sand that had blown from the tall aeolian dune on the eastern margin of the park into North Pond. The sand was trucked to the lake-ward side of the dune. Beach grasses were planted by conservation groups to help stabilize the dune. Cars are no longer permitted on the beach, except for access to residences on the barrier. Fencing was erected to help stabilize sand and keep people off the dunes. Our beach profiling indicates that these efforts have helped protect the dunes.

STOP 5. (Optional) Sandy Pond Inlet
We will walk along the beach approximately 2 miles north to Sandy Pond Inlet. There we will examine the beach, inlet, pond and washover.

B4: EURYPTERIDS AND FACIES CHANGES WITHIN SILURIAN/DEVONIAN 'EURYPTERID BEDS' OF NEW YORK STATE
S.J.Ciurca, Jr.
Rochester, New York
Perhaps nowhere else in the world are eurypterids found in the abundance they are within the Siluro-Devonian strata of New York State. More importantly, little-understood cyclic sequences, mostly within an evaporite basin, preserved a multitude of distinctive eurypterid faunas. Many of these are currently known, and several now known, need to be better understood. This is especially true of Akron-Cobleskill horizons (see Ciurca 1978, 1994) that are providing abundant remains of successor faunas to those of the well-known Bertie faunas, viz. Eurypterus remipes (older) and Eurypterus lacustris Faunas.
The purpose of this paper is to comment on Bertie Group and overlying Akron-Cobleskill occurrences – their distribution geographically and stratigraphically of microbialites and eurypterids – and suggest that much more research is required if we are to truly understand the paleoenvironment not only of the sedimentary rocks in which we find specimens, but the environment in which the animals actually lived. The association of many of the eurypterid horizons with stromatolites/thrombolites is particularly emphasized. This is an exciting new area of observation and research.
The evolution of fish, and other organisms, has taught us that given enough time, many animals evolve to occupy disparate environments within the marine realm and often within the fresh water realm (rivers and lakes). Many authors have already suggested that the various eurypterid morphologies we encounter can be attributed to their existence in a variety of environments. Yet, it has proved difficult to provide specific environments for specific eurypterids – especially faunas that contain a great variety of species (forms) co-mingled like those of the Bertie Group assemblages.
The discovery of numerous post Akron-Cobleskill eurypterid horizons (Ciurca 1973, 1994) and horizons within the Cobleskill Limestone (itself) of eastern New York suggested lithologically and faunally that the Bertie Group needed redefinition. Redefinition was proposed previously (Ciurca 1980) and provided for practical recognition of the Silurian-Devonian boundary across New York State from Albany westward to Buffalo and into the Niagara Peninsula of Ontario, Canada based upon the abrupt appearance of Erieopterus.
In addition, examination of the typical Bertie Group lithologies and faunas can help us look for and understand newly discovered eurypterid horizons. An example of this, discussed below, is the occurrence of numerous stromatolite horizons within most sequences (See section on Microbialites within the Bertie Group).
The eurypterid-bearing horizons mostly begin in basal Salina Group units that are more argillaceous than Bertie Group (and higher) horizons. While not much is known about facies relationships within these lower horizons (e.g. Pittsford and other members of the Vernon Formation), some observations have been made (Ciurca in NYSGA 1990). Of course, during the deposition of the Salina sequence, the thick red beds of the Vernon-Bloomsburg to the south and east were important to the paleoenvironmental setting in which we find the eurypterids. To the west of the basin were the ‘Niagaran’ reefs, some of which are believed to have continued growth into late Salina and Bertie time.
All of the Late Silurian and Early Devonian eurypterid ‘deposits’ indicate formation in shallow water and most are associated with features of desiccation represented by the numerous (cyclical) horizons bearing mudcracks, occasional ripple marks, rip-up clasts and probable strandline deposits. Uniquely, the Yale Peabody Museum ory is now the repository of a great collection of the sedimentary structures and sedimentological features, including a suite of associated lithological samples personally observed and collected over a period of about 40 years.

>B4: EURYPTERIDS AND FACIES CHANGES WITHIN SILURIAN/DEVONIAN 'EURYPTERID BEDS' OF NEW YORK STATE

Remington Arms Factory on left

Entering Illion Gorge (Steele Creek)
Ordovician Time Zone

Entering Silurian Time Zone

Vernon Red Shale

Syracuse Formation on left

Early Devonian limestones on left

STOP 1. Exposures of the Late Silurian Fiddlers Green Fm
Approximately the upper half of the Fiddlers Green Fm. (Bertie Group) is exposed along the road directly opposite the Litchfield Town Hall (Ciurca Locality 56, Cedarville at Jerusalem Hill Roads). In 1966, the exposure was a glacially polished surface on the Phelps Waterlime Member and very resistant to excavation. However, during this and many subsequent years, hundreds of specimens of eurypterids and associated fauna were obtained from this relatively small outcrop. This material is now in the Yale Peabody Museum in New Haven, Connecticut. The eurypterid-bearing units here are the Phelps Waterlime at the top of the exposure and the underlying finely-crystalline Victor Member. Eurypterus remipes is the common element of the eurypterid fauna here and has drawn collectors from all over to this area trying to find one.

POW/MIA Remembrance Bridge.

STOP 2. Exposures of the Late Silurian and Early Devonian Strata
Stratigraphically, this is an important section. At the base is the uppermost Fiddlers Green Fm. (Bertie Group) with eurypterids and salt hoppers. Overlying strata include the Forge Hollow, Cobleskill, Chrysler, Thacher and part of the Olney Formations. There are at least three eurypterid horizons present in the section. The Silurian/Devonian boundary lies within the lower part of the Chrysler Fm. here – this lower portion is rich in strontium (celestite) at Chittenango Falls. This section, again, exhibits the importance of microbialites in sections preserving eurypterid remains. In the upper portions of this section, within the ‘Thacher’ here, are more than two thick beds (more than 2.5 m) of stromatolites (including digitate forms) and thrombolites intimately associated with the Early Devonian eurypterid, Erieopterus.

STOP 3. Rock Cut Bioherm (New Name)
This road cut exposes what is here interpreted as another example of a patch reef within the Akron/Cobleskill sequence like that proposed for the Marcellus Falls area (Martisco Reef Complex). Above the sequence here is the lower portion of the overlying Chrysler Formation. While chert is a minor component there, as compared to the Marcellus Falls exposures, it allows for a direct correlation with the units exposed at Marcellus Falls. Both localities record the same post-Bertie eurypterid facies.

STOP 4. Martisco Reef Complex, Marcellus Falls
And Overlying Chrysler Formation
Interpreted herein (and associated website) to be a Late Silurian patch reef associated with the Akron/Cobleskill sedimentation in upstate New York in this area, and eastward to the Rock Cut Gorge and also westward to the Auburn area. Eurypterid paleoenvironments can only legitimately be interpreted if we take into account the known distribution of stromatoporoids biohermal and biostromal deposits and understand the impact of the variety of morphotypes exhibited within the Bertie Group (and overlying sequences) of microbialites as we come to recognize them within the eurypterid-bearing Late Silurian and Early Devonian sequences.
The most notable feature here is the dark chert facies which is seen to laterally replace the reef but also overlies what looks like the core of the reef – a highly dolomitized massive section with vugs, dolomite crystals, and silicified stromatoporoids. This lithology resembles parts of the Lockport Dolostone of western New York.

STOP 5. Cobleskill Limestone Stromatoporoid Biostrome
The intimate contact of an eurypterid horizon with deeper water facies is illustrated at this site. This may represent an extreme regression as eurypterid beds lie upon a massive stromatoporoid biostrome. And to complicate matters more, there are higher Eurypterus-bearing, pre-Erieopterus, units preserved upstream. This is the most complex area of eurypterid stratigraphy in upstate New York and is especially important because the units are all post-Bertie Group, i.e. post Eurypterus lacustris Biofacies. Thus, there are numerous eurypterid horizons exposed in the Owasco Outlet and we need to know why they are preserved here and how this important section relates to those to the west, south and east.