Usage:
Piper Formation of Ellis Group (MT*,ND*,WY*)
Piper Limestone of Ellis Group (MT*)
Piper Formation (ND)
Subunits:
(alphabetical): Bowes Member (MT*,ND*), Dunham Salt Member (ND), Firemoon Limestone Member (MT*,ND*), Kline Member (ND), Picard Member (ND), Poe Evaporite Member (ND), Saude Member (ND), Tampico Shale Member (MT*,ND*).
Geologic age:
Jurassic, Middle*
Bathonian*
Bajocian*
Type section, locality, area and/or origin of name:
Type section: about 1 mi southwest of Piper, on the northwest corner of an escarpment, east of the Bacon Ranch, in sec. 17, T. 14 N., R. 20 E., Fergus Co., MT. Named from town of Piper (Imlay and others, 1948).
AAPG geologic province:
Central Montana uplift*
Powder River basin*
Williston basin*
Bighorn basin*
Sweetgrass arch*
Montana folded belt*
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 ([ ]).