The Bryce Canyon area shows a record of deposition that spans from the last part of the Cretaceous period and the first half of the Cenozoic era. The ancient depositional environment of the region around what is now the park varied. The Dakota Sandstone and the Tropic Shale were deposited in the warm, shallow waters of the advancing and retreating Cretaceous Seaway (outcrops of these rocks are found just outside park borders). The colorful Claron Formation, from which the park's delicate hoodoos are carved, was laid down as sediments in a system of cool streams and lakes that existed from 63 to about 40 million years ago (from the Paleocene to the Eocene epochs). Different sediment types were laid down as the lakes deepened and became shallow and as the shoreline and river deltas migrated.