Usage:
Hercules Shale Member of Briones Sandstone of San Pablo Group (CA*)
Geologic age:
late Tertiary (late Miocene)*
Type section, locality, area and/or origin of name:
Named from Hercules Station on San Pablo Bay, Concord 15-min quadrangle, Contra Costa Co., CA (Lawson, 1914).
AAPG geologic province:
Northern Coast Range province*
Sacramento 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 ([ ]).