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National Geologic Map Database

Geologic Unit: Duncan

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 usage by the U.S. Geological Survey. Other usages by state geological surveys.

"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 does not conform with nomenclatural guidelines (CSN, 1933; ACSN, 1961, 1970; NACSN, 1983, 2005). This may be explained within brackets ([ ]).