A rill in a barnyard and the Grand Canyon represent, in the main, stages of valley erosion that began some millions of years apart.


'Uniformitarianism. An Inquiry into Principle, Theory, and Method in Geohistory and Biohistory', M. K. Hecht and W. C. Steere (eds.), Essays in Evolution and Genetics in Honor of Theodosius Dobzhansky (1970)

George Gaylord Simpson Quotes

A rill in a barnyard and the Grand Canyon represent, in the main, stages of valley erosion that began some millions of years apart.

A rill in a barnyard and the Grand Canyon represent, in the main, stages of valley erosion that began some millions of years apart.

A rill in a barnyard and the Grand Canyon represent, in the main, stages of valley erosion that began some millions of years apart.

A rill in a barnyard and the Grand Canyon represent, in the main, stages of valley erosion that began some millions of years apart.