Usage:
Helmer claystone bed (informal) of Van Bibber Shale Member of South Platte Formation of Dakota Group (CO*)
Informal. The rank or lithologic term should not be capitalized.
Geologic age:
Early Cretaceous*
Type section, locality, area and/or origin of name:
Not designated. Named from Helmer Mine, center W/2 E/2 SW/4 sec. 13, T. 7 S., R. 69 W., Kassler quadrangle, Douglas Co., CO (Waage, 1961).
AAPG geologic province:
Denver 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 ([ ]).