Geography
How Glacial Erratics Reveal Past Ice Sheet Movement
Quick fact
Some glacial erratics are so massive they are known as 'boulders' that weigh thousands of tons, and they can be found hundreds of kilometers away from their source bedrock, like the famous 'Plymouth Rock' in the U.S. which is itself a glacial erratic.
Why this is interesting
Have you ever seen a massive boulder sitting alone in a field, jutting out of a forest, or resting impossibly on a cliff, seemingly out of place? How did it get there, and what story can it tell about the landscape's history?