Usage:
Sedan Formation of Livingston Group (MT*)
Subunits:
(alphabetical): Bearpaw Shale Member (MT*), Lennep Sandstone Member (MT*).
Geologic age:
Late Cretaceous (Santonian to Campanian)*
Type section, locality, area and/or origin of name:
Type section: secs. 6, 7, 17, and 18, T. 4 N., R. 8 E., Park Co., MT. Named from town of Sedan, Gallatin Co., MT (Skipp and McGrew, 1977).
AAPG geologic province:
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 ([ ]).