Structure (recognizable features produced by deformation of rocks) maps of the St. Peter Sandstone, Prairie du Chien Group, and Jordan Sandstone; Isopach (thickness) maps of the St. Peter Sandstone and Prairie du Chien Group and aeromagnetic anomaly data (relative to the earth's magnetic field interpretation of magnetic data collected from airborne surveys indicating the distribution and concentration of magnetic minerals (primarily iron-bearing) within the upper crust of the earth, scale 1:125,000.