 photo credit: Heather Sloan, © American Museum of Natural History This boulder, shown on the shore at Siccar Point, Scotland, is part of the Old Red Sandstone Formation. About 400 million years ago, before there was an Atlantic Ocean separating the Americas from Eurasia and Africa, the Caledonian and Appalachian mountain ranges were formed. Sediments from these mountains accumulated in basins on their flanks. These sediments are collectively known as Old Red Sandstone. Today, long after the continents have been separated by the opening of the Atlantic Ocean, the matching belts of Old Red Sandstone in Scandinavia, the United Kingdom, and the American Northeast, provide compelling evidence for plate tectonic movements. |
