Usage:
/Johnson Member of Snake Creek Formation of Ogallala Group (NE-recognized locally in type area)
[Preoccupied. Name previously applied to Johnson Shale by Condra (1927) in NE.]
Geologic age:
late Tertiary (Miocene; Hemphillian NALMA)
Type section, locality, area and/or origin of name:
Type section: on the Vance Johnson Ranch (origin of name) [approx. 15+/- mi south of town of Agate, on Niobrara River, and 1.5 mi east of Route 29], near the head of Matthew's (Amer. Mus. Nat. Hist., v. 50, art. 2, p. 63, fig. 1, 1924) "East PLIOHIPPUS Draw," in NE/4 NW/4 sec. 32 and southeastern corner of SW/4 sec. 29, T. 26 N., R. 55 W., [Chalk Buttes NE 7.5-min quadrangle], Sioux Co., northwestern NE (Skinner and others, 1977).
AAPG geologic province:
Denver 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 ([ ]).