Usage:
Bald Peak Basalt of Contra Costa Group (CA*)
Bald Peak Formation of Contra Costa Group (CA)
Geologic age:
late Tertiary (Miocene)*
Type section, locality, area and/or origin of name:
[Type locality]: forms large part of Bald Peak [now Vollmer Peak] east of Berkeley, [in T. 1 N., R. 3 W., Lat. 37 deg. 53 min. 00 sec. N., Long. 122 deg. 13 min. 19 sec. W., southwestern corner Briones Valley 7.5-min quadrangle, Contra Costa Co.], San Francisco region, western CA (Lawson and Palache, 1902; Lawson, 1914).
AAPG geologic 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 ([ ]).