Usage:
Castle Reef Formation of Madison Group (MT*)
Castle Reef Dolomite of Madison Group (MT*)
Subunits:
(alphabetical) --all in MT: Dupuyer Creek unit* (informal), Gateway Pass unit* (informal), Sun River Member.
Geologic age:
Middle Mississippian (Visean; late Osagean to Meramecian)*
Type section, locality, area and/or origin of name:
Type section: north of Diversion Lake, on ridge that forms east side of Hannan Gulch, Teton Co., MT (Mudge and others, 1962).
Principal reference: in sec. 21, T. 27 N., R. 9 W., Teton Co., MT, Teton Co., MT (Nichols, 1984).
AAPG geologic province:
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 ([ ]).