To show how dependent the Colorado is on the high peaks for its flood-waters, I will mention that it is not till the snows of these high altitudes are fiercely attacked by the sun in May and June that the river has its annual great rise.

It would take only a slight lowering of the mean annual temperature now to furnish these peaks with ice caps.

The rainfall in the lower arid regions is from three to ten inches, increasing northward to fifteen and twenty-five.

On the peaks, of course, it is much greater.

Almost any climate can be had, from the hot arid to the wet frigid.