Geologic units in Orange county, Indiana

Blue River Group (Mississippian) at surface, covers 39 % of this area

Mostly micritic, skeletal, and oolitic limestone

West Baden Group (Mississippian) at surface, covers 25 % of this area

Shale, sandstone, and micritic and skeletal limestone

Stephensport Group (Mississippian) at surface, covers 24 % of this area

Sandstone, micritic and skeletal limestone, and shale

Raccoon Creek Group (Pennsylvanian) at surface, covers 7 % 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

Buffalo Wallow Group (Mississippian) at surface, covers 4 % of this area

Mostly shale and sandstone; also includes thin beds of micritic limestone. L, Leopold Limestone member