Geologic units in Kosciusko county, Indiana

Antrim Shale (Devonian) at surface, covers 53 % of this area

Black shale; gray shale and limestone in lower part

Muscatatuck Group (Devonian) at surface, covers 39 % of this area

Limestone and dolomite

Wabash Formation (Silurian) at surface, covers 5 % of this area

Limestone, dolomite, and argillaceous dolomite

Ellsworth Shale (Devonian-Mississippian) at surface, covers 3 % of this area

Green shale; some black shale in lower part