Usage:
Helmet Fanglomerate (AZ*)
Geologic age:
Oligocene*
Type section, locality, area and/or origin of name:
Not designated. Most continuous exposures are along north-trending line from point 0.75 mi southeast of Helmet Peak to point 1.25 mi north-northwest of Twin Buttes village, Pima mining district, Pima Co., southwestern AZ (Cooper, 1960).
AAPG geologic province:
Basin-and-Range province*
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 ([ ]).