Usage:
Simtustus Formation (OR)
Geologic age:
Tertiary
Miocene, middle
Type section, locality, area and/or origin of name:
Type section: exposures on east canyon wall near Lake Simtustus Reservoir, behind Pelton Dam on Deschutes River west of Madras, Jefferson Co., OR (Smith, 1986).
AAPG geologic province:
Cascades province
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 ([ ]).