Legend (groundwater/Bedrock_Geology_NE_IL)

Geology at Bedrock Surface (0) Pennsylvanian Carbondale Fm. (Pc) Pennsylvanian Tradewater Fm. (Pt) Devonian Muscatatuck Group (Dm) Silurian System (Su) Ordovician Maquoketa Group (Om) Ordovician Galena Group (Op) Ordovician Platteville Group (Op) Ordovician Ancell Group (Oa) Ordovician Prairie du Chien Group (Opdc) Cambrian System (C) Des Plaines Complex (Pz) Bedrock Topography Hillshade (1) High : 227 Low : 120