Lake Michigan on the Wisconsin side of the lake shows layers of limestone and a beach that does not show when water levels are high. I took this photo on the Door Peninsula. Here you may find fossils embedded in the sedimentary rocks. It's a great place to explore.
The Great Lakes water levels rise and fall. The photo is from 1985 when cottages were undermined by high water and waves on Lake Michigan. This year the lakes are the lowest they have been for 130 years and there is a lot of sand on the beach. Yet, it's never a good idea to build too close the water since the lakes are dynamic. They are always changing.
Global warming may continue to cause lower water levels, but no one really knows. Read more about the Great Lakes and their changes in The Dynamic Great Lakes