|Name||Glen Park Formation, Hannibal Shale, Chouteau Limestone, McCraney Limestone, Prospect Hill Siltstone, and Starrs Cave Limestone|
|Geologic age||Mississippian (Tourniaisian)|
Sedimentary > Clastic > Mudstone > Shale (Bed)
Sedimentary > Carbonate > Limestone (Bed)Limestone can be sandy, oolitic or cherty, can contain geodes or drusy quartz.
Sedimentary > Clastic > Siltstone (Bed)
|Comments||Thickness from stratigraphic columns: Chouteau Ls (0-20’) in southern Illinois (south of 40 degrees north latitude); Chouteau Ls (0-20’), McCraney Ls (0-60’), Prospect Hill Sltst (0-25’), and Starrs Cave Ls (0-10’) in northern Illinois (north of 40 degrees north latitude). From oldest to youngest, the units are Glen Park Formation, Hannibal Shale, Chouteau Limestone in southern Illinois; and McCraney Limestone, Prospect Hill Siltstone, and Starrs Cave Limestone (all of which are equivalent to the Chouteau Limestone) in northern Illinois. [The stratigraphic columns show the Glen Park and Hannibal Shale as part of the New Albany Shale in southern Illinois, and the Hannibal Shale as part of the New Albany Shale in northern Illinois, HOWEVER, the Glen Park and Hannibal Shale are portrayed on the geologic map as Mississippian, a unit (Mk) defined by age and distinct from the New Albany Shale (DMna).] The Chouteau Limestone, McCraney Limestone, Prospect Hill Siltstone, and Starrs Cave Limestone in northern Illinois comprise the lower part of the Mammoth Cave Group (as portrayed in the stratigraphic column).|
Kolata, D.R., comp., 2005, Bedrock Geology of Illinois: Champaign, Ill., Illinois State Geological Survey, Illinois Map Series 14, scale 1:500,000.
|Counties||Adams - Calhoun - Greene - Jersey - Pike - Scott|