Usage:
No current usage.
(†Contra Costa Lake Bed (CA) replaced with Siesta Formation of Contra Costa Group. See Siesta.)
Geologic age:
late Tertiary (Miocene)
Type section, locality, area and/or origin of name:
Lies chiefly on northeast slope of hills west of San Pablo Creek, forming boundary between Contra Costa and Alameda Cos. in that part of its course about 4.5 mi northeast of State University, San Francisco Bay region, western CA (Cooper, 1894).
AAPG geologic province:
Santa Cruz 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 ([ ]).