Beulah-Zap bed (informal) of Sentinel Butte Formation of Fort Union Group (ND)
Beulah-Zap lignite bed (informal) of Sentinel Butte Formation of Fort Union Group (ND)
Informal. The rank or lithologic term should not be capitalized.
Tertiary
Paleocene
Not synopsized to date.
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 ([ ]).