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Geologic units in Ulster county, New York

Austin Glen Formation (Pawlet in Vermont) (Middle Ordovician) at surface, covers 35 % of this area

Austin Glen Formation (Pawlet in Vermont) - graywacke, shale.

Lithology: graywacke; shale

Plattekill and Ashokan Formations (Middle Devonian) at surface, covers 16 % of this area

Plattekill Formation - shale, sandstone; Ashokan Formation-shale, sandstone.

Lithology: shale; sandstone

Bloomsburg Formation (Upper Silurian) at surface, covers 10 % of this area

Bloomsburg Formation - shale, sandstone; Guymard Quartzite; Otisville Shale; Shawangunk Conglomerate-sandstone, conglomerate.

Undifferentiated Lower Hamilton Group (Middle Devonian) at surface, covers 8 % of this area

Undifferentiated Lower Hamilton Group - Panther Mountain, Mount Marion, Stony Hollow, and Union Springs shales and sandstones.

Lithology: shale; sandstone; limestone

Onondaga Limestone (Lower to Middle Devonian) at surface, covers 7 % of this area

Onondaga Limestone - Schoharie Formation-shale, limestone; Carlisle Center Siltstone; Esopus Shale.

Lithology: shale; limestone; siltstone

Quassaic Quartzite (Upper Ordovician) at surface, covers 4 % of this area

Quassaic Quartzite - quartzite, sandstone, conglomerate.

Moscow Formation (Middle Devonian) at surface, covers 3 % of this area

Moscow Formation - in west: Cooperstown and Portland Point shale and sandstone Members; In east: "Manorkill" and Portland Point shale and sandstone Members.

Lithology: shale; sandstone

Honesdale Formation (Upper Devonian) at surface, covers 3 % of this area

Honesdale Formation - sandstone, shale.

Lithology: sandstone; shale

Undifferentiated Lower Devonian and Silurian rocks (Lower Devonian - Silurian) at surface, covers 3 % of this area

Undifferentiated Lower Devonian and Silurian rocks - in northern Ulster County: Port Ewen thru Manlius Limestones; Rondout Dolostone; Binnewater Sandstone; High Falls Shale. In Orange County: Kanhouse Sandstone; Woodbury Creek Formation-shale, sandstone; Esopus Shale; Connelly Conglomerate; Central Valley Sandstone; New Scotland Limestone thru Rondout Dolostone; Decker Limestone; Poxono Island Formation-shale, dolostone; Longwood Shale; Green Pond Conglomerate.

Undifferentiated Hamilton Group (Middle Devonian) at surface, covers 2 % of this area

Undifferentiated Hamilton Group - shale, siltstone. In eastern Orange County: Skunnemunk Formation-sandstone, conglomerate; Bellvale Formation-shale, sandstone; Cornwall Shale.

Slide Mountain Formation (Upper Devonian) at surface, covers 2 % of this area

Slide Mountain Formation - sandstone, shale, conglomerate.

Upper Walton Formation (Upper Devonian) at surface, covers 2 % of this area

Upper Walton Formation - shale, sandstone, conglomerate.

Rondout Formation (Upper Silurian) at surface, covers 1 % of this area

Rondout Formation - dolostone, limestone; Binnewater Sandstone; High Falls Shale; Warwarsing Limestone; Decker Limestone; Bossardville Limestone; Poxono Island Formation-shale, dolostone.

Glenerie Formation (Lower Devonian) at surface, covers 0.8 % of this area

Glenerie Formation - limestone, chert.

Mount Merino and Indian River Formations (Ordovician) at surface, covers 0.4 % of this area

Mount Merino and Indian River Formations - shale, slate, cherts.

Lithology: shale; slate; chert

Lower Walton Formation (Upper Devonian) at surface, covers 0.3 % of this area

Lower Walton Formation - shale, sandstone, conglomerate.

Helderberg Group (Lower Devonian) at surface, covers 0.3 % of this area

Helderberg Group - West of Albany: Alsen, Becraft, New Scotland, Kalkberg, Coeymans, and Manlius Limestones; Rondout Dolostone. South of Albany: Port Ewen, Alsen thru Manlius Limestones; Rondout Dolostone.

Wappinger Group (Cambrian - Lower Ordovician) at surface, covers < 0.1 % of this area

Wappinger Group - (including Fishkill limestone and dolostone): Copake Formation ?-limestone, dolostone; Rochdale Formation-limestone, dolostone; Halcyon Lake Dolostone-locally cherty; Briarcliff Dolostone; Pine Plains Formation-dolostone, shale, oolite; Stissing Formation-dolostone, shale.

Normanskill Shale (Middle Ordovician) at surface, covers < 0.1 % of this area

Normanskill Shale - minor mudstone, sandstone.

Lithology: shale; mudstone; sandstone

Oneonta Formation (Middle - Upper Devonian) at surface, covers < 0.1 % of this area

Oneonta Formation - shale, sandstone, conglomerate.