USGS Visual Identifier
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Geologic Unit: Big Mountain

Big Mountain Shale Member of Keyser Limestone (WV*,VA*)

Silurian, Late*
Devonian, Early
Geologic Province:
Appalachian basin*

Areal Extent:

Type Locality:
Exposures at Big Mountain, about 1.5 mi west of village of Upper Tract, Pendleton Co., east-central WV. (Swartz, 1929)

Unit Name History:
Named (Swartz, 1929). Age changed (Cardwell, 1968). Age modified to Late Silurian, only (Denkler and Harris, 1988).

Note: If you need more information, please contact Nancy Stamm (
Asterisks (*) indicate usage by the U.S. Geological Survey. Other usages by state geological surveys.

"No current usage" implies that a name has been abandoned or that it has fallen into disuse. Former usage and, if known, replacement name given in parentheses ().

Slashes (/) indicate unit name usage violates the 1983 North American Stratigraphic Code. This violation may be explained within brackets ([ ]).

U.S. Department of the Interior, U.S. Geological Survey, Reston, VA, USA
Database project personnel
Last modified: 15-Jan-2013