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Copake and Halcyon Lake Formations, Rochdale Limestone

Copake and Halcyon Lake Formations, Rochdale Limestone - Columbia County: Copake Formation-limestone, dolostone; Halcyon Lake Formation-chert, calc-dolostone.
State New York
Name Copake and Halcyon Lake Formations, Rochdale Limestone
Geologic age Lower Ordovician
Comments part of Beekmantown and Stockbridge Groups, Potsdam Sandstone, and Vermont Valley Sequence up to 3500 ft. (1100 m). Note that unit has no name on printed map, (part of Wappinger Group - inferred from other map sheets). Used formations for unit name here.
Primary rock type limestone
Secondary rock type dolostone (dolomite)
Other rock types chert
Lithologic constituents
Major
Sedimentary > Carbonate > Limestone
Minor
Sedimentary > Carbonate > Dolostone (Calcareous)
Sedimentary > Chemical > ChertHalcyon Lake Formation-chert
Map references
NYS Museum, NYS Geological Survey, NYS Museum Technology Center, 1999, 1:250,000 Bedrock geology of NYS, data is distributed in ARC/INFOr EXPORT format (with ".e00" extension) in 5 seperate files based on printed map sheets, http://www.nysm.nysed.gov/gis.html.
Unit references
D. W. Fisher; Y. W. Isachsen, L. V. Rickard, 1970, Geologic Map of New York State, consisting of 5 sheets: Niagara, Finger Lakes, Hudson-Mohawk, Adirondack, and Lower Hudson, New York State Museum and Science Service, Map and Chart Series No. 15, scale 1:250000.
Counties Columbia - Dutchess - Orange