Geologic units in Antrim county, Michigan

Ellsworth Shale (Late Devonian) at surface, covers 62 % of this area

Ellsworth Shale

Antrim Shale (Late Devonian) at surface, covers 17 % of this area

Antrim Shale

Coldwater Shale (Mississippian) at surface, covers 14 % of this area

Coldwater Shale

Traverse Group (Middle Devonian) at surface, covers 5 % of this area

Traverse Group

Bedford Shale (Late Devonian) at surface, covers 2 % of this area

Bedford Shale