Geologic units in Johnson county, Indiana

Borden Group (Mississippian) at surface, covers 53 % 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

New Albany Shale (Devonian-Mississippian) at surface, covers 34 % of this area

Black and greenish-gray shale

Muscatatuck Group (Devonian) at surface, covers 14 % of this area

Limestone and dolomite