The Precambrian in Washington, US

Paleontology and geology

Most of the land that is now Washington State did not exist along the west coast of North America until the Jurassic. Late Precambrian rocks from the ancient North American continent extend a few kilometers into easternmost Washington. These are a thick sequence of sediments that were deposited in an expansive, very shallow sea. They show mud cracks, ripple marks and very rare trace fossils.