No current usage.
(†Marshall Shale (AR,OK) is same as Fayetteville Shale. See Fayetteville.)
Mississippian
Not designated. Named from Marshall Mountain, just east of Marshall, Searcy Co., AR (Branner and Simonds, 1891).
Arkoma 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 ([ ]).