Clarno Formation (OR*)
Tertiary
Eocene*
Eocene, middle
Oligocene, earliest(?)*
Not designated. Named from Clarnos Ferry on John Day River, 20 mi east of Antelope, OR.
Eastern Columbia basin
Blue 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 ([ ]).