Geologic units in Clay county, Indiana

Raccoon Creek Group (Pennsylvanian) at surface, covers 82 % 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

Carbondale Group (Pennsylvanian) at surface, covers 17 % of this area

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

Blue River Group (Mississippian) at surface, covers 0.8 % of this area

Mostly micritic, skeletal, and oolitic limestone

West Baden Group (Mississippian) at surface, covers 0.1 % of this area

Shale, sandstone, and micritic and skeletal limestone