Geologic units in Green Lake county, Wisconsin

Additional scientific data in this geographic area

Cambrian, undivided (Cambrian) at surface, covers 67 % of this area

Sandstone with some dolomite and shale, undivided; includes Trempealeau, Tunnel City, and Elk Mound Formations

Prairie du Chien Group (Ordovician) at surface, covers 18 % of this area

Dolomite with some sandstone and shale; includes Shakopee and Oneota Formations

Sinnipee Group (Ordovician) at surface, covers 8 % of this area

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

Ancell Group (Ordovician) at surface, covers 4 % of this area

Orthoquartzitic sandstone with minor limestone, shale and conglomerate; includes Glenwood and St. Peter Formations

Rhyolite (Early Proterozoic) at surface, covers 4 % of this area

Ash-flow tuffs and interbedded volcaniclastic sedimentary rocks and cogenetic granite (unit Xga) exposed as inliers in southern Wisconsin. In central Wisconsin pink, flow-banded rhyolite and chert-cemented breccia inferred to be 1760 Ma.