When I give lectures about the Great Lakes, I always mention how these lakes were formed during the last ice age by a series of glaciers that came down from the north to scour out the lake basins. On Kelleys Island, you can see the handiwork of the glaciers stretching over this preserved 3 acres that still clearly show the hand of the glaciers.
These grooves scoured in a limestone bed thousands of years ago are the most famous glacial grooves in the world.
Much of this area was covered in glacial till (dirt and rocks deposited by the melting glaciers) until the 1970s. Excavation was a meticulous process. Today, an almost 400 feet long stretch of grooves is exposed and protected for us all to marvel at.