Page:All Over Oregon and Washington.djvu/278



physical geography of Oregon and Washington is unique, and gives a great variety of climates. Approaching from the Pacific, we find, first, a narrow skirting of coast, from one to six miles in width. Back of this rises the Coast Range of mountains, from three to five thousand feet high. Beyond this range are fine, level prairies, extending for from forty to sixty miles eastward. Beyond these prairies rises again the Cascade Range, from five to eight thousand feet in height, and having to the east of them high, rolling prairies, extending to the base of the Blue Mountains, which trend south-westwardly, leaving plains and small valleys, to the east, between themselves and the Snake River, which forms the eastern boundary of Oregon and a portion of Washington

These differences in altitude would, of themselves, produce differences in temperature. But the great reason why the change is so great from the coast to the Snake River lies in the arrangement of the mountain-ranges; and in the fact that the north-west shore of the American continent is washed by a warm current from the China seas. The effect of this current is such that places in the same latitude on the Atlantic and Pacific coasts are several degrees—sometimes twenty degrees—warmer on the latter coast, than on the former. This gives a temperature at which great