Usage:
Phi Kappa Formation (ID*)
Subunits:
Basin Gulch Quartzite Member (ID*).
Geologic age:
Ordovician to early Silurian*
Type section, locality, area and/or origin of name:
Not designated. Named from exposures on Phi Kappa Creek, in T. 6 N., R. 19 E., Custer Co., ID (Westgate and Ross, 1930).
Phi Kappa Creek shown as the type locality (Ross, 1934).
AAPG geologic province:
Snake River basin*
Idaho Mountains 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 ([ ]).