The Old Red Sandstone

Part of Hall of Planet Earth.

The Old Red Sandstone AMNH/R.Mickens

Today, matching belts of sedimentary rock, known as the Old Red Sandstone, are found in Scandinavia, the United Kingdom, and eastern North America. This puzzling distribution of similar rocks can be explained by plate tectonics. Sediments that originally formed 400 million years ago on a vast supercontinent were later separated when the landmass broke apart into the continents we see today.