Oneonta Formation (NYDgo;2)

State	New York
Name	Oneonta Formation
Geologic age	Middle - Upper Devonian
Original map label	Dgo
Comments	part of Genesee Group 1200-1500 ft. (370-460 m), Secondary unit description from USGS Lexicon website (ref. NY046) and reference NY021: The Oneonta Formation occurs at the top of core PT-1 and the lower parts are exposed along Rte 30 near Grand Gorge. Unit is composed of red, green, and gray mudstones with subordinate red to gray, very fine- to fine-gained sandstones. Mudstones range from fissile and relatively nonbioturbated to blocky and intensely bioturbated with desiccation cracks throughout representing flood-basin deposits. Sandstone sets are sharp-based, cm- to dm-thick sheets and lenses, cross-bedded or planar bedded flood deposits. The major sandstone bodies are interpreted as fluvial channel deposits. Gradationally overlies Gilboa Formation in the Schoharie Valley. Overlies Manorkill Formation to the east. Age is Middle and Late Devonian (Bridge and Willis, 1994).
Primary rock type	shale
Secondary rock type	sandstone
Other rock types	conglomerate
Lithologic constituents	Major Sedimentary > Clastic > Mudstone > Shale Minor Sedimentary > Clastic > Sandstone Incidental Sedimentary > Clastic > Conglomerate
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. [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. Bridge, J.S. and Willis, B.J., 1994, Marine transgressions and regressions recorded in Middle Devonian shore-zone deposits of the Catskill clastic wedge: Geological Society of America Bulletin, v. 106, no. 11, p. 1440-1458.
Geographic coverage	Chenango - Delaware - Otsego - Schoharie - Ulster