Have you ever been hiking in the forest and come upon a house size boulder? Where do these things come from? How did they get there?
Last week I learned that these boulders are called Glacial Erratics. The one in the picture above is located near Table Rock in the Gunks, outside of New Paltz, New York. There are a lot bigger ones scattered through the woods there.
These huge boulders were transported, possibly hundreds of miles, by 3,000 foot thick glaciers that covered most of North America just 13,000 years ago. The boulders are called erratics because they’re made out of different rock than the local Shawangunk conglomerate that you find on the cliffs here.
So if you see big boulders in the woods around you that seem out oddly out of place, they’re not there because aliens dropped them from outerspace. Think glaciers.