Geologic units in Vermilion county, Illinois

Shelburn-Patoka Formations undivided (Pennsylvanian (Kasimovian)) at surface, covers 35 % of this area

Shelburn-Patoka Formations undivided.

Tradewater Formation (Pennsylvanian (Bashkirian to Moscovian)) at surface, covers 23 % of this area

Tradewater Formation

Carbondale Formation (Pennsylvanian (Moscovian to Kasimovian)) at surface, covers 21 % of this area

Carbondale Formation.

Bond Formation (Pennsylvanian (Kasimovian)) at surface, covers 14 % of this area

Bond Formation

Borden Siltstone (Mississippian (Tourniaisian to Visean)) at surface, covers 6 % of this area

Borden Siltstone, includes Chouteau Limestone in east-central Illinois.

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 1 % of this area

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

Carbondale Group (Pennsylvanian) at surface, covers < 0.1 % of this area

Mostly shale and sandstone; also includes thin beds of limestone, clay, and coal. S, Springfield Coal Member

Raccoon Creek Group (Pennsylvanian) at surface, covers < 0.1 % of this area

Mostly shale and sandstone; also includes thin beds of limestone, clay, and coal. B, Buffaloville Coal Member; LB, Lower Block Coal Member

Borden Group (Mississippian) at surface, covers < 0.1 % of this area

Mostly siltstone; lenses of crinodial limestone in upper part. Much cherty and silty limestone and dolomite in northwest. NP, top of New Providence Shale