Usage:
Cone Member of Marias River Shale of Colorado Group (MT*)
Geologic age:
Late Cretaceous (Cenomanian to Turonian)*
Type section, locality, area and/or origin of name:
Type section: in NW/4 SE/4 sec. 13, T. 22 N., R. 1 W., Toole Co., MT. Named from USGS vertical-angle bench mark (VABM) "Cone" at location of type (Cobban and others, 1959).
AAPG geologic province:
Montana folded belt*
Sweetgrass arch*
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 ([ ]).