Pond Ridge Rhyolite of /Taum Sauk Group of /St. Francois Mountains Volcanic Supergroup (MO-recognized locally in St. Francois Mountains area)
[Name Taum Sauk used for both group and formation within it (Taum Sauk Rhyolite has priority); name St. Francois Mountains applied concurrently to two different units in same area; a [supergroup] name combines a geographic name with the term ["supergroup,"] and no lithic designation is included (see ACSN, 1970; NACSN, 1983, 2005, 2021).]
Precambrian
Type section: in NE/4 NW/4 sec. 3, T. 33 N., R. 3 E., Ironton quadrangle, Iron Co., MO. Origin of name not stated by author, but probably named from ridge south of Graniteville, Iron Co., MO (Berry, 1976).
Midcontinent region
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 ([ ]).