Usage:
Duncan Sandstone of El Reno Group (OK*)
Duncan Member of San Angelo Formation of Pease River Group (TX*)
Geologic age:
Middle Permian (Guadalupian)*
Type section, locality, area and/or origin of name:
Type locality: Duncan, county seat of Stephens Co., central southern OK. Forms an escarpment just north of Duncan (Gould, 1924; see also Scott and Ham, 1957).
AAPG geologic province:
Anadarko basin*
Chautauqua platform*
Palo Duro basin*
Permian basin*
South Oklahoma folded belt*
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 ([ ]).