USGS Visual Identifier
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Geologic Unit: Deerfield

Deerfield Basalt of Newark Supergroup (MA*)

Jurassic, Early*
Geologic Province:
New England province*
Deerfield basin*
Areal Extent:

Type Locality:
Not designated. Forms the core of Deerfield Mountain, Greenfield quadrangle, Franklin Co., MA (Emerson, 1898).

Unit Name History:
Named Deerfield diabase (Emerson, 1891).
Revised to Deerfield sheet of Holyoke Diabase (Emerson, 1898).
Revised to Deerfield diabase of the Newark Group (Willard, 1951).
MA State Geol. Map usage (Zen and others, 1983).
Age modified (Olsen, 1984).
Revised to Deerfield Basalt of the Newark Supergroup (Robinson and Luttrell, 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