Geologic units in DeKalb county, Indiana

Antrim Shale (Devonian) at surface, covers 79 % of this area

Black shale; gray shale and limestone in lower part

Ellsworth Shale (Devonian-Mississippian) at surface, covers 11 % of this area

Green shale; some black shale in lower part

Coldwater Shale (Mississippian) at surface, covers 10 % of this area

Mostly gray shale

Muscatatuck Group (Devonian) at surface, covers 0.4 % of this area

Limestone and dolomite