Some of these rocks weigh several hundred pounds and have traveled as far as 1,500 feet, which leaves us with the question: "How do they move?"
The stones move only every two or three years and most tracks develop over three or four years.
Stones with rough bottoms leave straight striated tracks while those with smooth bottoms wander. Stones sometimes turn over, exposing another edge to the ground and leaving a different track in the stone's wake.