Geologic units in Scott county, Minnesota

Upper Cambrian (Upper Cambrian) at surface, covers 52 % of this area

Sandstone, siltstone, shale, and dolostone; includes the Jordan Sandstone and St. Lawrence Formation, and the Mazomanie, Lone Rock, and Davis Formations of the Tunnel City Group.

Lower Ordovician (Lower Ordovician) at surface, covers 39 % of this area

Dolostone, sandy to silty dolostone, and sandstone; includes the Shakopee Formation and Oneota Dolomite of the Prairie du Chien Group.

Middle and Upper Cambrian (Middle and Upper Cambrian) at surface, covers 6 % of this area

Sandstone, siltstone, and shale; includes the Wonewoc Sandstone, Eau Claire Formation, and Mt. Simon Sandstone.

Middle and Upper Ordovician (Middle and Upper Ordovician) at surface, covers 2 % of this area

Shale, dolomitic limestone, and sandstone; includes the Decorah Shale of the Galena Group, the Platteville and Glenwood Formations, and the St. Peter Sandstone.

North Branch mafic volcanic sequence (Mesoproterozoic) at surface, covers < 0.1 % of this area

North Branch mafic volcanic sequence.

Sandstone, siltstone, and local conglomerate (Mesoproterozoic) at surface, covers < 0.1 % of this area

Sandstone, siltstone, and local conglomerate. Includes the Hinckley Sandstone and Fond du Lac (youngest detrital zircons ~1,000 Ma) and Solar Church Formations; deposition in eolian, fluvial, and lacustrine environments.