But what stumps me is the mountain range three thousand feet high, crossing the desert and the canyon just above where we crossed the river.

How did the river cut through that without the help of a split or earthquake ?" "I'll admit that is a poser to me as well as to you.

But I suppose Wallace could explain it as erosion.

He claims this whole western country was once under water, except the tips of the Sierra Nevada mountains.

There came an uplift of the earth's crust, and the great inland sea began to run out, presumably by way of the Colorado.