| State | Illinois |
|---|---|
| Name | Kimmswick (Trenton) Limestone and Decorah Formation |
| Geologic age | Upper Ordovician (Stage 6) |
| Lithologic constituents |
Major
Sedimentary > Carbonate > Limestone (Bed)Limestone can be bioclastic.
Sedimentary > Carbonate > Dolostone (Bed)Dolomite can be bioclastic.
Minor
Sedimentary > Clastic > Mudstone > Claystone > Bentonite (Bed)K-bentonite
Sedimentary > Clastic > Mudstone > Shale (Bed)
|
| Comments | The Galena Group is comprised, from oldest to youngest, of the Kimmswick (Trenton) Limestone and Decorah Formation (which contains the Millbrig K-bentonite Bed) according to the stratigraphic column for southern Illinois (south of 40 degrees north latitude) on the back of the geologic map. |
| Stratigraphic units | Galena Group, Millbrig K-bentonite Bed |
| References | Kolata, D.R., comp., 2005, Bedrock Geology of Illinois: Champaign, Ill., Illinois State Geological Survey, Illinois Map Series 14, scale 1:500,000. |
| NGMDB product | |
| Counties | Alexander - Calhoun - Jersey - Monroe - Pike - Randolph |