Geologic units in Washington county, Wisconsin

Additional scientific data in this geographic area

Silurian, undivided (Silurian) at surface, covers 78 % of this area

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

Maquoketa Formation (Ordovician) at surface, covers 21 % of this area

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

Sinnipee Group (Ordovician) at surface, covers 0.4 % of this area

Dolomite with some limestone and shale; includes Galena, Decorah, and Platteville Formations