Glacial Potholes at Interstate Park

We recently stopped at Interstate Park which is on the border between Minnesota and Wisconsin.  It is a wonderful park and home to the largest concentration of Glacial Potholes in the world.   The glacial potholes form when rocks in a fast moving river fall into a small divot and swirl around knocking against the rock and acting as a drill.   They make circular drill holes some times called “Witches’ Cauldrons”.   Often quite small, some in the park are over 60 feet deep!