Geologic units in Lake county, Michigan

Bayport Limestone (Mississippian) at surface, covers 10 % of this area: Bayport Limestone
Lithology: limestone; dolostone (dolomite); sandstone; shale; chert; evaporite
Michigan Formation (Mississippian) at surface, covers 44 % of this area: Michigan Formation
Lithology: shale; black shale; sandstone; dolostone (dolomite); limestone; evaporite
Coldwater Shale (Mississippian) at surface, covers 1 % of this area: Coldwater Shale
Lithology: shale; limestone; dolostone (dolomite); sandstone; siltstone
Red beds (Jurassic) at surface, covers 0.8 % of this area: Red beds
Lithology: shale
Marshall Sandstone (Mississippian) at surface, covers 9 % of this area: Marshall Sandstone
Lithology: sandstone; siltstone
Saginaw Formation (Pennsylvanian) at surface, covers 35 % of this area: Saginaw Formation
Lithology: sandstone; shale; coal; limestone