Usage:
Twin Knobs Formation (ID*,UT*)
Subunits:
Naomi Peak Tongue (ID*,UT*).
Geologic age:
early Middle Cambrian*
Type section, locality, area and/or origin of name:
Type area: from crest to east slope of Portneuf Range, from sec. 1, T. 10 S., R. 38 E., to sec. 29, T. 10 S., R. 39 E., Bannock Co., ID (Oriel and others, 1971).
AAPG geologic province:
Snake River 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 ([ ]).