Usage:
Umatilla Member of Saddle Mountains Basalt of Columbia River Basalt Group (ID*,OR*,WA*)
Umatilla Member of Saddle Mountains Basalt of /Yakima basalt subgroup [informal] of Columbia River Basalt Group (ID*,OR*,WA*)
[Yakima basalt subgroup considered informal and should not be capitalized. "Subgroup" not recognized as a formal stratigraphic rank term (CSN, 1933; ACSN, 1961, 1970; NACSN, 1983, 2005, 2021). Columbia River Basalt Group adopted by the ID, OR, and WA Geol. Surveys, and the USGS (rules suspended).]
Geologic age:
late Tertiary (middle Miocene)*
Type section, locality, area and/or origin of name:
Forms Umatilla Rapids of Columbia River, [no longer exist; covered by Lake Wallula, in T. 5 N., R. 28 E., WA-OR State line, Benton and Umatilla Cos., Umatilla quadrangle (scale 1:125,000), northeast of Umatilla, Umatilla Co., OR] (see Laval, 1966).
Type locality: exposures and cuts along an abandoned railroad 1 km west of the north abutment of McNary Dam, in extreme SE/4 SE/4 SE/4 sec. 4, T. 5 N., R. 28 E., Umatilla quadrangle, Benton Co., WA (Swanson and others, 1979).
AAPG geologic province:
Eastern Columbia 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 ([ ]).