Usage:
No current usage.
(Rocks of †Yonna Formation (OR) reallocated to several unnamed units.)
Geologic age:
late Tertiary (latest Miocene to early Pliocene)
Type section, locality, area and/or origin of name:
Type locality: along west side of Yonna Valley, in T. 38 S., R. 11 1/2 E., Klamath Co., Willamette meridian and baseline, Klamath Co., southwestern OR (Newcomb, 1958).
AAPG geologic province:
Southern Oregon 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 ([ ]).