Quotes by William Morris Davis

Any statement is of geographical quality if it contains a reasonable relation between some inorganic element of the earth on which we live, acting as a control, and some element of the existence or growth or behavior or distribution of the earth's organic inhabitants, serving as a response; more briefly, some relation between an element of inorganic control and one of organic response.

It seems most probable, that the many pre-existent streams in each river basin concentrated their water in a single channel of overflow, and that this one channel survives- a fine example of natural selection.