USGS Visual Identifier
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Geologic Unit: Greylock

Greylock Schist (MA*,VT).

Proterozoic, Late*
Cambrian, Early*
Geologic Province:
New England province*

Areal Extent:

Type Locality:
Exposures on Mount Greylock, Berkshire Co., northern MA (Dale, 1891).

Unit Name History:
Named Greylock schists (Dale, 1891).
Redescribed as Greylock Schist; Age modified (Herz, 1958).
Extended into VT (Thompson, 1959).
Age modified (Ratcliffe, 1979).
MA State Geol. Map usage (Zen and others, 1983).

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