Geologic units in Porter county, Indiana

Ellsworth Shale (Devonian-Mississippian) at surface, covers 64 % of this area: Ellsworth Shale - Green shale; some black shale in lower part
Lithology: shale; black shale
Antrim Shale (Devonian) at surface, covers 33 % of this area: Antrim Shale - Black shale; gray shale and limestone in lower part
Lithology: black shale; shale; limestone
Muscatatuck Group (Devonian) at surface, covers 3 % of this area: Muscatatuck Group - Limestone and dolomite
Lithology: limestone; dolostone (dolomite)