Jackfork Group (AR,OK*)
Jackfork Sandstone (AR*,OK)
GROUP STATUS (alphabetical): Brushy Knob Formation (AR), Chicksaw Creek Formation (OK), Game Refuge Formation (OK) or Game Refuge Sandstone (OK*), Irons Fork Mountain Formation (AR), Markham Hill Formation (OK*), Prairie Hollow Shale (OK), Prairie Mountain Formation (OK*), Wesley Formation (OK) or Wesley Shale (OK*), Wildhorse Mountain Formation (OK*).
Mississippian, Late* (local)
Not designated. Named from Jackfork Mountain, Pittsburg and Pushmataha Cos., OK (Taff, 1902).
Ouachita 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 ([ ]).