Usage:
Stonewall Formation (MT,ND,SD,WY)
Stonewall Formation of Bighorn Group (MT,ND)
Geologic age:
Silurian
Type section, locality, area and/or origin of name: (See Canadian Lexicon)
Stonewall quarry, Stonewall, LSD 13-30-13-2 East of Principal Meridian (EPM), Manitoba, Canada (CSPG Western Canada Lexicon).
AAPG geologic province:
Williston 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 ([ ]).