Geologic units in Scott county, Illinois

Carbondale Formation (Pennsylvanian (Moscovian to Kasimovian)) at surface, covers 35 % of this area

Carbondale Formation.

Meppen Limestone, Fern Glen Formation, and Burlington-Keokuk Limestone (Mississippian (Tourniaisian to Visean)) at surface, covers 26 % of this area

Meppen Limestone, Fern Glen Formation, and Burlington-Keokuk Limestone.

Warsaw Formation and Salem Limestone (Mississippian (Visean)) at surface, covers 16 % of this area

Warsaw Formation and Salem Limestone in western Illinois.

Tradewater Formation (Pennsylvanian (Bashkirian to Moscovian)) at surface, covers 9 % of this area

Tradewater Formation

Glen Park Formation, Hannibal Shale, Chouteau Limestone, McCraney Limestone, Prospect Hill Siltstone, and Starrs Cave Limestone (Mississippian (Tourniaisian)) at surface, covers 7 % of this area

Glen Park Formation, Hannibal Shale, Chouteau Limestone, McCraney Limestone, Prospect Hill Siltstone, and Starrs Cave Limestone.

St. Louis Limestone (Mississippian (Visean)) at surface, covers 5 % of this area

St. Louis Limestone.

New Albany Shale, Blocher Shale, Sylamore Sandstone, Selmier Shale, Sweetland Creek Shale, Grassy Creek Shale, Saverton Shale, and Louisiana Limestone (Middle Devonian (Givetian) to Upper Devonian (Fammenian)) at surface, covers 3 % of this area

New Albany Shale, Blocher Shale, Sylamore Sandstone, Selmier Shale, Sweetland Creek Shale, Grassy Creek Shale, Saverton Shale, and Louisiana Limestone.

Silurian System undivided (Silurian (Llandovery to Pridoli)) at surface, covers 0.1 % of this area

Silurian System undivided, includes Sexton Creek Limestone, St. Clair Limestone, and Moccasin Springs Formation in southern Illinois; includes Wilhelmi Formation, Elwood Dolomite, Kankakee Dolomite, Joliet Dolomite, Sugar Run Dolomite, and Racine Dolomite in northeastern Illinois; includes Mosalem, Tete des Morts, Blanding, Sweeney, Marcus, and Racine Dolomites in northwestern Illinois.