Missouri Mountain Shale (AR*,OK*,TX*?)
Missouri Mountain Formation (AR*)
Missouri Mountain Slate (OK*)
Named from exposures in Missouri Mountains, Polk and Montgomery Cos., southwestern AR (US geologic names lexicons, USGS Bull. 896, 1200).
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 ([ ]).