Thunder Springs Member of Redwall Limestone (AZ*,UT*)
Mississippian, Early*
Osagean*
Type section: in cliff west of springs at head of Thunder River about 2 mi north of Colorado River, Grand Canyon, AZ (McKee, 1963).
Plateau sedimentary province*
Black Mesa 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 ([ ]).