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Mineral Resources > Online Spatial Data > Geology > by state > New York Geology

Geologic units in Rensselaer county, New York

Poultney Formation ("A" Member) (Cambrian) at surface, covers 0.2 % of this area

Poultney Formation ("A" Member) - shale, limestone; Hatch Hill Formation-shale, dolostone; West Castleton Formation-shale, limestone, conglomerate.

Lithology: shale; limestone; dolostone (dolomite); conglomerate

Canajoharie Shale (Middle Ordovician) at surface, covers 8 % of this area

Canajoharie Shale - includes Hortonville and Ira Shales in Vermont.

Lithology: black shale

Undivided metasedimentary rock and related migmatite (Middle Proterozoic) at surface, covers < 0.1 % of this area

Undivided metasedimentary rock and related migmatite.

Lithology: metasedimentary rock; migmatite

Taconic Melange (Middle Ordovician) at surface, covers 2 % of this area

Taconic Melange - chaotic mixture of Early Cambrian thru Middle Ordovician pebble to block-size clasts in a pelitic matrix of Middle Ordovician (Barneveld) age. Rims and floors earlier submarine gravity slides of Taconian Orogeny.

Lithology: melange

Normanskill Shale (Middle Ordovician) at surface, covers 1 % of this area

Normanskill Shale - minor mudstone, sandstone.

Lithology: shale; mudstone; sandstone

Rensselaer Graywacke (Cambrian? ) at surface, covers 22 % of this area

Rensselaer Graywacke - minor shale.

Lithology: graywacke; shale

Undifferentiated Middle Ordovician thru Lower Cambrian allochthonous rocks (Cambrian - Ordovician) at surface, covers 4 % of this area

Undifferentiated Middle Ordovician thru Lower Cambrian allochthonous rocks - principally pelite; lesser quartzite, limestone, conglomerate, graywacke.

Lithology: mudstone; quartzite; limestone; conglomerate; graywacke

Hortonville Formation (Ordovician) at surface, covers < 0.1 % of this area

Hortonville Formation - Black, carbonaceous and pyritic slate and phyllite, locally sandy; brown weathered limy beds are common near base. Occurs east of Highgate Springs, Champlain, and Orwell thrusts.

Lithology: slate; phyllite

St. Catherine Formation (Cambrian) at surface, covers < 0.1 % of this area

St. Catherine Formation - Purple, gray-green, and variegated slate and phyllite containing minor interbeds of white to green quartzite; locally albitic. Purple and green chloritoid-bearing slate and phyllite is within dashed line in northern Taconic Range, but not separated farther south.

Lithology: slate; phyllite; quartzite

Walloomsac Formation (Middle Ordovician) at surface, covers 7 % of this area

Walloomsac Formation - slate, phyllite, schist, metagraywacke.

Lithology: slate; phyllite; schist; metasedimentary rock

Nassau Formation (Cambrian ?) at surface, covers 37 % of this area

Nassau Formation - south of 43 degrees; slate, shale, thin quartzite, includes Stuyvesant Conglomerate, Diamond Rock Quartzite, Curtis Mountain Quartzite, and Bomoseen Graywacke Members.

Lithology: shale; quartzite; slate; conglomerate; graywacke

Trenton and Black River Groups, undivided (Middle Ordovician) at surface, covers < 0.1 % of this area

Trenton and Black River Groups, undivided - Glens Falls and Orwell Limestones. In Canada: Lindsay, Verulam, Bodcaygeon, Gull River Limestones; Shadow Lake Dolostone.

Lithology: limestone

Mount Merino and Indian River Formations (Ordovician) at surface, covers 1 % of this area

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

Lithology: shale; slate; chert

Germantown Formation (Cambrian) at surface, covers 3 % of this area

Germantown Formation - south of Troy; shale, conglomerate, limestone.

Lithology: shale; conglomerate; limestone

Austin Glen Formation (Pawlet in Vermont) (Middle Ordovician) at surface, covers 1 % of this area

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

Lithology: graywacke; shale

Stockbridge Formation (Cambrian - Lower Ordovician) at surface, covers 0.4 % of this area

Stockbridge Formation - calcitic and dolomitic marble.

Lithology: marble

Elizaville Formation (Cambrian - Ordovician) at surface, covers < 0.1 % of this area

Elizaville Formation - shale, argillite, quartzite.

Lithology: shale; argillite; quartzite

Beekmantown Group (in part) (Lower Ordovician) at surface, covers < 0.1 % of this area

Beekmantown Group (in part) - In St. Lawrence Valley: Ogdensburg Dolostone (Beauharnois Dolostone in Canada); In Champlain Valley: Providence Island Dolostone; Fort Cassin Formation-limestone, dolostone; Fort Ann Formation (Spellman of Clinton and Essex Counties)-limestone, dolostone; Cutting Formation-dolostone (locally cherty), limestone, siltstone. In Vermont: includes Bridport, Bascom, Cutting, and Shelburne carbonates.

Lithology: dolostone (dolomite); limestone; chert; siltstone

Poultney Formation ("B" and "C" Members) (Ordovician) at surface, covers 2 % of this area

Poultney Formation ("B" and "C" Members) - shale, slate, siltstone.

Lithology: shale; slate; siltstone

Cambrian thru Middle Ordovician carbonate rock (Cambrian - Middle Ordovician) at surface, covers 0.5 % of this area

Cambrian thru Middle Ordovician (Barneveld) carbonate rock - occuring as slivers caught along thrusts of later allochthones, or carbonate blocks in Taconic Melange.

Lithology: carbonate; melange

Austerlitz Phyllite (Cambrian?) at surface, covers 5 % of this area

Austerlitz Phyllite - minor quartzite

Lithology: phyllite; quartzite

Greenstones and tuffs and/or basalt (Cambrian?) at surface, covers < 0.1 % of this area

Greenstones and tuffs and/or basalt

Lithology: greenstone; tuff; basalt

Stuyvesant Falls Formation (Ordovician) at surface, covers 1 % of this area

Stuyvesant Falls Formation - south of Troy; shale, siltstone.

Lithology: shale; siltstone

Glacial and Alluvial Deposits (Quaternary) at surface, covers 3 % of this area

Glacial and Alluvial Deposits - underlying bedrock geology unknown.

Lithology: alluvium; glacial drift