Usage:
Lake Michigan Formation (IL*,IN*,MI*,WI*)
Subunits:
(alphabetical): Lake Forest Member (IL*,MI*,WI*), Sheboygan Member (IL*,MI*,WI*), South Haven Member (IL*,MI*,WI*), Waukegan Member (IL*,MI*,WI*), Winnetka Member (IL*,MI*,WI*), Ravinia facies (informal) (IL) or [?]Ravinia Sand Member (MI).
Geologic age:
Quaternary*
Type section, locality, area and/or origin of name:
Type section (subsurface): Lake Michigan bottom sediments extending from point 19 km east to point 51 km east of Waukegan, Lake Co., IL. At latter point, Core 143, depth-interval 0 to 326 cm, water depth 119 m (Willman and Frye, 1970).
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 ([ ]).