Usage:
Lance Formation (CO*,MT*,WY*)
Called Ceratops beds and Lance Creek Beds in early reports.
Subunits:
(alphabetical): Black Buttes coal group (informal) (WY), Ilo Ridge Member (WY), Red Rim Member (CO*,WY*), Torrington Member (WY).
Geologic age:
Late Cretaceous (Maastrichtian)*; locally early Tertiary (Paleocene)*
Type section, locality, area and/or origin of name:
Type locality: Lance Creek area, north-central part Niobrara Co. (formerly a part of Converse Co.), WY; mouth of Lance Creek is in sec. 11, T. 39 N., R. 62 W., [Lance Creek 30- x 60-min quadrangle] (US geologic names lexicons, USGS Bull. 896, 1200).
AAPG geologic province:
Bighorn basin*
Central Montana uplift*
Green River basin*
Powder River basin*
Sioux uplift*
Williston basin*
Wind River 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 ([ ]).