No current usage.
(†Rough Creek Shale Member of Tesnus Formation (TX) replaced with informal "lower shale member of Tesnus Formation.")
Late Mississippian (Chesterian)
Not designated. Origin of name not stated (Udden and others, 1916).
Permian 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 ([ ]).