Michigan is the only state in the nation to border four of the five Great Lakes--giving it the nickname, the Great Lakes State. This abundance of shoreline translates to a multitude of rock exposed by waves and currents. Nearly the entire history of Earth is on display in Michigan, from 3.6-billion-year-old gneisses to potholes drilled by modern rivers. Michigan Rocks! guides you to 56 world-class geologic sites scattered from Isle Royale and the...