The western mountains now stand, in the dim past there was a long shallow ditch. As the mighty mountains rose up, ridge after ridge, a vast area of the earth’s crust was heaved up in a high plateau. When the mountains ware young, a swift river ran down their western slopes to the sea. The plateau uplifted slowly and the river was both swift and strong.

As the river bed rose, the swift waters washed it away, biting deeper into the ground. In 50 million years, while the land uplifted on either side, the busy river we call the Colorado, dug Grand Canyon a mile deep.