Usage:
Black Rock diabase breccia dike (informal) (MA)
Informal. The rank or lithologic term should not be capitalized.
Geologic age:
Jurassic, Early
Type section, locality, area and/or origin of name:
Named from outcrops at Black Rock, south of Mount Holyoke House, Mount Holyoke quadrangle, Hampshire Co., central MA (Emerson, 1898).
AAPG geologic province:
New England province
Hartford basin
For more information, please contact Nancy Stamm, Geologic Names Committee Secretary.
Asterisk (*) indicates published by U.S. Geological Survey authors.
"No current usage" (†) implies that a name has been abandoned or has fallen into disuse. Former usage and, if known, replacement name given in parentheses ( ).
Slash (/) indicates name conflicts with nomenclatural guidelines (CSN, 1933; ACSN, 1961, 1970; NACSN, 1983, 2005, 2021). May be explained within brackets ([ ]).