Canajoharie Shale

Includes Hortonville and Ira Shales in Vermont.
State New York
Name Canajoharie Shale
Geologic age Middle Ordovician
Lithologic constituents
Major
Sedimentary > Clastic > Mudstone > Shale > Black-shale
Comments part of Lorraine, Trenton, and Black River Groups up to 1600 ft. (490 m). Secondary unit description from USGS Geologic Names lexicon (ref. NY046): Middle Ordovician Canajoharie Shale is one of several black shales in a belt of autochthonous Paleozoic rocks (exclusive of the Taconic sequence) that occupies the Champlain, Hudson, and Mohawk valleys. The black shales also include Hortonville Slate, Snake Hill Formation, or Normanskill Shale; these are all correlative with each other.
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.

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

https://ngmdb.usgs.gov/Geolex/search

NGMDB product
Counties Essex