Geologic units in Lenawee county, Michigan

Coldwater Shale (Mississippian) at surface, covers 78 % of this area

Coldwater Shale

Antrim Shale (Late Devonian) at surface, covers 5 % of this area

Antrim Shale

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

Traverse Group

Bedford Shale (Late Devonian) at surface, covers 4 % of this area

Bedford Shale

Marshall Sandstone (Mississippian) at surface, covers 3 % of this area

Marshall Sandstone

Berea Sandstone (Late Devonian) at surface, covers 2 % of this area

Berea Sandstone

Sunbury Shale (Mississippian-Devonian) at surface, covers 2 % of this area

Sunbury Shale

Dundee Limestone (Middle Devonian) at surface, covers 0.6 % of this area

Dundee Limestone

Detroit River Group (Middle Devonian) at surface, covers 0.1 % of this area

Detroit River Group

Coldwater Shale (Mississippian) at surface, covers < 0.1 % of this area

Shale; gray; clayey thin bedded; siderite nodules common; as much as 150 feet thick.

Sunbury and Bedford Formations, Undivided (Devonian and/or Mississippian) at surface, covers < 0.1 % of this area

Shale and siltsone; shale, black to brownish-black, carbonaceous in upper one third of interval, gray to bluish-gray, clayey with occasional siltstone lamina and thin beds in lower two-thirds of interval.

Antrim Shale (Devonian) at surface, covers < 0.1 % of this area

Shale; dark brown to black; carbonaceous, thinly laminated; 0 to 230 feet thick.