Geologic units in Le Sueur county, Minnesota

Lower Ordovician (Lower Ordovician) at surface, covers 57 % of this area

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

Upper Cambrian (Upper Cambrian) at surface, covers 34 % 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.

Middle and Upper Ordovician (Middle and Upper Ordovician) at surface, covers 8 % 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.

Middle and Upper Cambrian (Middle and Upper Cambrian) at surface, covers 1 % of this area

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