5. When a glacier moves over the land, it carries with it a large load of sand, gravel, boulders of all sizes and a variety of assorted dirt. This mixture is known as glacial till or as "glacial drift." The Driftless Area of Western Wisconsin missed getting this load of geologic "junk" dropped on it when the last glacier ran over the rest of the state about 12-15000 years ago. As a result, the topography of this part of the state looks very different from the remainder of the state (or from most of the rest of the Midwest). This 3-D map from the Wisconsin State Geological Society clearly shows the difference between the heavily carved southwestern part of the state and the relatively flat balance. I circled this area in yellow to make it even clearer.