Usage:
Cochrane Formation of Hunton Group (OK)
Cochrane Member of Chimneyhill Limestone (OK)
Cochrane Formation of /Chimneyhill subgroup [informal] of Hunton Group (OK)
["Subgroup" not recognized as a formal stratigraphic rank term (CSN, 1933; ACSN, 1961, 1970; NACSN, 1983, 2005, 2021). Chimneyhill subgroup considered informal and should not be capitalized.]
Geologic age:
early Silurian (Llandovery)
Type section, locality, area and/or origin of name:
Not designated. Origin of name not stated by author (Maxwell, 1936).
Type section: in SE/4 sec. 5, T. 2 N., R. 6 E. [Pontotoc Co., OK]. Well exposed along banks of small tributary entering Chimneyhill Creek (Amsden, 1957).
AAPG geologic province:
Arkoma basin
South Oklahoma 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 ([ ]).