Geologic units in Putnam county, Indiana

Blue River Group (Mississippian) at surface, covers 34 % of this area

Mostly micritic, skeletal, and oolitic limestone

Borden Group (Mississippian) at surface, covers 29 % 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

Sanders Group (Mississippian) at surface, covers 19 % of this area

Mostly skeletal limestone, cherty in lower part

Raccoon Creek Group (Pennsylvanian) at surface, covers 18 % 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

West Baden Group (Mississippian) at surface, covers 0.9 % of this area

Shale, sandstone, and micritic and skeletal limestone