Usage:
Sweeney Formation (IL)
Sweeney Member of Hopkinton Formation (IL,IA)
Geologic age:
early Silurian (Llandovery)
Type section, locality, area and/or origin of name:
Type section: Bluff of Mississippi River in Mississippi Palisades State Park at parking area, 1.5 km north of Savanna-Sabula Bridge, SW/4 SE/4 NE/4 sec. 33, T. 25 N., R. 3 E., Carroll Co., IL. Named from Sweeney Islands in Mississippi River (Willman, 1973).
AAPG geologic province:
Wisconsin arch
Iowa shelf
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 ([ ]).