GEOLEX database Geologic Unit: Yonna Usage: No current usage. (Rocks of †Yonna Formation (OR) reallocated to several unnamed units.) Age: Tertiary Miocene, latest to Pliocene, early Geologic Province: Great Basin province Areal Extent: OR(sc) Type Locality: Along west side of Yonna Valley, in T. 38 S., R. 11 1/2 E., Klamath Co., OR (Newcomb, 1958). Unit Name History: Named (Newcomb, 1958). Age modified (Pickthorn and Sherrod, 1990). Abandoned (Sherrod and Pickthorn, in press). Note: If you need more information, please contact Nancy Stamm (nstamm@usgs.gov). Asterisks (*) indicate usage by the U.S. Geological Survey. Other usages by state geological surveys. "No current usage" implies that a name has been abandoned or that it has fallen into disuse. Former usage and, if known, replacement name given in parentheses (). Slashes (/) indicate unit name usage violates the 1983 North American Stratigraphic Code. This violation may be explained within brackets ([ ]). U.S. Department of the Interior, U.S. Geological Survey, Reston, VA, USA URL http://ngmdb.usgs.gov/ngmdb/ngm_catalog.ora.html Database project personnel Last modified: 7-Jan-2007