Oneonta Formation

Shale, sandstone, conglomerate.
State New York
Name Oneonta Formation
Geologic age Middle - Upper Devonian
Lithologic constituents
Major
Sedimentary > Clastic > Mudstone > Shale
Minor
Sedimentary > Clastic > Sandstone
Incidental
Sedimentary > Clastic > Conglomerate
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).
References

Fisher, D.W., Isachsen, Y.W., and Rickard, L.V., 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 1:250,000.

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.

NGMDB product
Counties Albany - Chenango - Delaware - Greene - Orange - Otsego - Schoharie - Sullivan - Ulster