Usage:
Four Mile Dam Formation of Traverse Group (MI*)
Subunits:
Dock Street Clay Member (MI).
Geologic age:
Middle Devonian*
Type section, locality, area and/or origin of name:
Type section: at Four Mile Dam on Thunder Bay River, Alpena Co., northeastern MI (Cooper and Warthin, 1941).
AAPG geologic province:
Michigan 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 ([ ]).