Dinosaur, again

Dinosaur NM is in a semi-arid environment now but in the past it has gone through many climate changes and elevation changes. At the moment it is 7500 feet high (2300 m). So when we stood at Harpers Corner and overlooked the deep canyons of the Green and Yampa Rivers on either side we were standing on seashells and river-rounded rocks and looking down on eons of layers of time back to the Cambrian time.