Eau Claire is right on the edge of the unglaciated area, the Driftless Area. It is important as a region because it remained glacier free, while all around the glaciers scoured down the terrain. That is why it is so hilly. The Wisconsin Dells are in this area too and are really popular because of the ancient landforms. When the glaciers receded, and before the meltwater filled in the basin that became Lake Michigan, a lot of the finely ground particles blew to the Michigan side of the lake. That is why we have a coastline of sand dunes in MI. My hometown was built upon dunes, and our sand is free of shells, salt, & such that the oceans have so it squeaks when you walk on it.
Probably too much information, but geology was a major subject for me in archaeology. Also, we were taught about glaciers all through school.