Iberville Shale (in Vermont) (NYOi;1)

State	New York
Name	Iberville Shale (in Vermont)
Geologic age	Middle Ordovician
Original map label	Oi
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): Geographically extended the Iberville formation from southern Quebec, CAN into northwestern VT. Consists of noncalcareous shale, rhythmically interbedded with thin quartz-silty dolomite, uniform fine-grained dolomite, and in lower part, calcareous shale. Thickness is 1000 to 2000 feet. Overlies the Stony Point formation and underlies the Hathaway formation. The Iberville is of Middle Ordovician age.
Primary rock type	shale
Secondary rock type	dolostone (dolomite)
Other rock types
Lithologic constituents	Major Sedimentary > Clastic > Mudstone > Shalein lower part, calcareous shale Minor Sedimentary > Carbonate > Dolostonein lower part, calcareous shale
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. USGS Geologic Names Lexicon (GEOLEX) [http://ngmdb.usgs.gov/Geolex/]