USGS Visual Identifier
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Geologic Unit: Coys Hill

Coys Hill Porphyritic Granite Gneiss (MA*)
Coys Hill Granite (NH*)

Devonian, Early*

Geologic Province:
New England province*

Areal Extent:

Type Locality:
Coys Hill, west-central MA (Emerson, 1917).

Unit Name History:
[Please note: only the Zen and others (1983) and Robinson and Luttrell (1985) references include synopses here. The remaining references have yet to be added from the GNC index card files. Until then, feel free to contact us if you would like complete bibliographic citations.]
First used as Coys Hill granite (Emerson, 1898).
Named Coys Hill Granite (Emerson, 1917).
Age modified (Field, 1975).
Extended into NH; Age modified; Removed from New Hampshire plutonic series/suite (Ashwal and others, 1979).
Isotopic dating (Robinson, 1979).
MA State Geol. Map usage (Zen and others, 1983).
Redescribed as Coys Hill Porphyritic Granite Gneiss in MA (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