Geologic units in Monroe county, Indiana

Borden Group (Mississippian) at surface, covers 44 % 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 29 % of this area

Mostly skeletal limestone, cherty in lower part

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

Mostly micritic, skeletal, and oolitic limestone

West Baden Group (Mississippian) at surface, covers 8 % of this area

Shale, sandstone, and micritic and skeletal limestone

Raccoon Creek Group (Pennsylvanian) at surface, covers 0.8 % 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

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

Sandstone, micritic and skeletal limestone, and shale