Ever come across a rock that looked strangely out of place? The odds are good that it’s a glacial erratic, transported by an ice flow and left somewhere else when melting occurred, in some cases hundreds of miles away from the original location.
Erratics can range from palm-size pebbles to boulders as big as houses. They rest in fields, on mountainsides, and under the sea. But these wandering rocks—like the one pictured, near Ingleborough mountain, in England’s Yorkshire Dales—stand out from their surroundings.