USGS Visual Identifier
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Geologic Unit: West Rock

West Rock Diabase (CT*)
West Rock Dolerite (CT*)

Jurassic, Early*

Geologic Province:
New England province*
Hartford basin*
Areal Extent:

Type Locality:
Type area: West Rock, New Haven quadrangle, New Haven Co., CT (Fritts, 1962).

Unit Name History:
Named West Rock Diabase (Fritts, 1962). Redefined West Rock Dolerite (Rodgers, 1985).

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