Geologic units in Leelanau county, Michigan

Antrim Shale (Late Devonian) at surface, covers 39 % of this area: Antrim Shale
Lithology: black shale; limestone
Traverse Group (Middle Devonian) at surface, covers 53 % of this area: Traverse Group
Lithology: limestone; shale
Detroit River Group (Middle Devonian) at surface, covers 2 % of this area: Detroit River Group
Lithology: dolostone (dolomite); limestone; sandstone
Ellsworth Shale (Late Devonian) at surface, covers 4 % of this area: Ellsworth Shale
Lithology: shale; siltstone; sandstone