USGS Visual Identifier
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Geologic Unit: Dalton

Dalton Formation (MA*,CT*,VT*)

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

Areal Extent:

Type Locality:
Dalton, Berkshire Co., western MA (Emerson, 1892, unpublished).

Unit Name History:
Named Dalton phyllite (Emerson, 1892, unpublished report).
Overview; Revised to Dalton formation (Emerson, 1917).
Extended into VT (Osberg, 1952).
Age modified (Zen and Hartshorn, 1966; Ratcliffe, 1974).
Extended into CT (Ratcliffe and Harwood, 1975).
Age modified (Ratcliffe and Hatch, 1979; Stanley and others, 1982).
MA State Geol. Map usage (Zen and others, 1983).
Areal limits (Thompson, 1990).
Revised (Burton, 1993).

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