USGS Visual Identifier
National Geologic Map Database logo GEOLEX database

Geologic Unit: Fourmile

Fourmile Gneiss (MA*)

Proterozoic, Late*
Ordovician, Late
Geologic Province:
New England province*

Areal Extent:

Type Locality:
Cascade on Fourmile Brook, immediately west of MA Highway 63 at Northfield Farms, Northfield 7.5-min quadrangle, Franklin Co., northwestern MA (Ashenden, 1973).

Unit Name History:
Named (Ashenden, 1973) [From GNU records (USGS DDS-6; Reston GNULEX); complete bibliographic citation and synopsis not given].
MA State Geol. Map usage (Zen and others, 1983).
Age modified; Overview (Robinson and Luttrell, 1985).
Isotopic dating (Tucker and Robinson, 1990).

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