Geologic units in Door county, Wisconsin

Additional scientific data in this geographic area

Silurian, undivided (Silurian) at surface, covers 96 % of this area

Dolomite, undivided; includes Cayugan, Niagaran, and Alexandrian series

Maquoketa Formation (Ordovician) at surface, covers 4 % of this area

Shale, dolomitic shale and dolomite; includes overlying Neda Formation (age uncertain) consisting of oolitic iron oxides and shale