Geologic units in Ogemaw county, Michigan

Michigan Formation (Mississippian) at surface, covers 69 % of this area

Michigan Formation

Marshall Sandstone (Mississippian) at surface, covers 14 % of this area

Marshall Sandstone

Coldwater Shale (Mississippian) at surface, covers 13 % of this area

Coldwater Shale

Saginaw Formation (Pennsylvanian) at surface, covers 3 % of this area

Saginaw Formation

Red beds (Jurassic) at surface, covers 0.5 % of this area

Red beds

Bayport Limestone (Mississippian) at surface, covers < 0.1 % of this area

Bayport Limestone