Usage:
Yearian Volcanics of Challis Volcanic Group (ID)
[Challis Volcanic Group adopted by the ID and MT Geol. Surveys, and the USGS (rules suspended).]
Geologic age:
Tertiary
Eocene
Type section, locality, area and/or origin of name:
Not designated. Named from Yearian Creek, Lemhi quadrangle, Lemhi Co., ID (Anderson, 1961).
AAPG geologic province:
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 ([ ]).