USGS Visual Identifier
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Geologic Unit: Mount Toby

Mount Toby Formation of Newark Supergroup (MA*)

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

Type Locality:
Extensively developed in the main mass of Mount Toby and exposed in the bed of Roaring Brook on the east flank of Mount Toby, Mount Toby quadrangle, Franklin Co., MA (Emerson, 1898).

Unit Name History:
Named Mount Toby Conglomerate (Emerson, 1891).
Described (Emerson, 1898).
Revised (Willard, 1951; Leo and others, 1977).
Abandoned (Peper, 1977).
Age modified (Cornet 1977).
MA State Geol. Map usage (Zen and others, 1983).
Revised to Mount Toby Formation 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