Oswayo and Venango Formations

Oswayo and Venango Formations - shale, siltstone, sandstone; replaced eastwardly by Cattaraugus Formation-shale, sandstone, conglomerate.
State New York
Name Oswayo and Venango Formations
Geologic age Upper Devonian
Comments part of Conewango Group 450-650 ft. (140-200 m). Secondary unit description from USGS Geologic Names lexicon (ref. NY046): Named Oswayo beds for Oswayo Creek in Olean quadrangle, NY. Consists of olive-green to rusty-colored sandy shales, with here and there thin sandstone layers with limonitic seams or incrustations. Includes marine invertebrates. Thickness is 160 to 250 feet. Unit underlies Knapp beds and overlies (probably unconformably) Cattaraugus beds. [Venango Formation] includes all strata from top of upper bounding key bed, the Woodcock Sandstone Member (Venango First sand), to the base of its lower key bed, the Panama Conglomerate Member (Venango Third sand). Formation is about 280 to 330 ft thick in study area. Consists of varying amounts of light-gray conglomerate, conglomeratic sandstone, and sandstone; gray and greenish-gray siltstone; and dark-gray to brownish-gray and minor grayish red shale. Where marker beds are not recognized, contacts are generally mapped by projection of interval thickness. Overlies Chadakoin Formation and underlies Oswayo Formation. Interfingers with Catskill Formation toward the southeast where redbeds begin to dominate. Depositional environment of oil sands interpreted as offshore bar and beach, tidal channels, and subaqueous dunes. Age is Late Devonian. [Cattaraugus Formation] Named for Cattaraugus Co., southwestern NY. Consists of red and green shales with flaggy sands. Thickness is 200 ft. Underlies Mount Herman or Salamanca conglomerate; overlies Wolf Creek conglomerate. Distinguished from Catskill beds by paleontologic evidence.
Primary rock type shale
Secondary rock type siltstone
Other rock types sandstone; conglomerate
Lithologic constituents
Major
Sedimentary > Clastic > Mudstone > Shale
Minor
Sedimentary > Clastic > Siltstone
Sedimentary > Clastic > Sandstone
Incidental
Sedimentary > Clastic > ConglomerateCattaraugus Formation only
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 Allegany - Cattaraugus - Chautauqua - Erie