Usage:
Umpqua Formation (CA,OR*)
Umpqua Group (OR)
Subunits:
GROUP STATUS: Roseburg, Lookingglass, and Flournoy Formations [not adopted by USGS].
FORMATION STATUS (ascending): Bushnell Rock, Tenmile, White Tail Ridge, and Camas Valley Members [not adopted by USGS].
Geologic age:
Tertiary
Eocene, middle*
Eocene, early*
Type section, locality, area and/or origin of name:
Type section: occurs along north Umpqua River, about 17 mi northeast of Roseburg, Douglas Co., OR (Weaver and others, 1944).
AAPG geologic province:
Oregon-Washington Coast Ranges province*
Klamath 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 ([ ]).