USGS Visual Identifier
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Geologic Unit: Dorchester

Dorchester Member of Roxbury Conglomerate (MA*)

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

Areal Extent:

Type Locality:
Named from Dorchester district of Boston, where it is exposed at several places (Dodge, 1881, 1882).

Unit Name History:
Named Dorchester slate (Dodge, 1881, 1882).
Revised Dorchester slate member of Roxbury conglomerate (Emerson, 1917).
Overview (Billings, 1976).
Age changed (Bailey, 1978).
Age discussed (Goldsmith and others, 1982).
MA State Geol. Map usage (Zen and others, 1983).
Not used (Socci and Smith, 1990).
Overview (Goldsmith, 1991).

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