Undifferentiated Hamilton Group

Shale, siltstone. In eastern Orange County: Skunnemunk Formation-sandstone, conglomerate; Bellvale Formation-shale, sandstone; Cornwall Shale.
State New York
Name Undifferentiated Hamilton Group
Geologic age Middle Devonian
Lithologic constituents
Sedimentary > Clastic > Siltstone
Sedimentary > Clastic > Mudstone > Shale
Sedimentary > Clastic > Sandstone
Sedimentary > Clastic > Conglomerate
Comments part of Hamilton Group 2600-2800 ft. (790-850 m). Secondary unit description from USGS Geologic Names lexicon (ref. NY046): [Skunnemunk Formation ] Named the Skunnemunk conglomerate for Skunnemunk Mountain, Orange Co., NY. Unit is a conglomerate that may represent Oneonta formation or may be younger or equivalent to the coarse beds of the Chemung in southern Catskills, or may be a local feature. Thickness is 300 to 2500 feet. Overlies the Bellvale flags. The Skunnemunk is of Late Devonian age.

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.

USGS Geologic Names lexicon found at: http://ngmdb.usgs.gov/Geolex/


NGMDB product
Counties Herkimer - Orange - Sullivan - Ulster