Page:An Illustrated History of the State of Oregon.djvu/20

14 the line of perpetual snow, dome the dark evergreen forests that cover the range.

Between these two mountain ranges lies the great valley of the Willamette, a hundred and fifty miles long and fifty miles wide, the gem and glory of the Pacific coast. The character and value of this valley agriculturally and industrially is discussed elsewhere, and we speak of it here only in its topographical relations to the dominating geological conditions of the region in which it is such an interesting element.

Taking our stand once more on the summit of the Cascade range we look still eastward over a vast, though broken and seared valley, 150 miles wide, against the slopes and pinnacles of the Blue mountains. This range has the same north and south trend as the others, though as its southward extension approaches the southern line of Oregon it breaks down into spars and isolated buttes, and finally terminates in the great volcanic plateau along the 43 parallel of latitude. Through this great depression between the Cascade and Blue Mountains, two rivers, the Des Chutes on its western and the John Day on its eastern side, run northward into the Columbia.

Still eastward, for 100 miles from the main ridge of the Blue mountains to the eastern line of the State, stretches a country quite unlike that west of that range. It is a region of valleys separated by detrached mountain ridges and traced by small rivers, which, while having the same northward flow as those before mentioned, enter Snake river far above its junction with the Columbia, and within its great volcanic valley that extends from the Blue mountains to the Rocky mountains a distance of nearly 1,000 miles. These valleys and mountain ranges have topographically or geologically little in common with those of the western and middle portions of the State.

It is needful that we now go southward and take our observations from the great Klamath plateau, that constitutes the separation between the north flowing and south and west flowing waters of Oregon. This sweeps eastward from the east foot of the Cascade range, on a width of a degree of latitude, at least 200 miles. It is a vast region of lakes, many of them without outlet, yet absorbing the constant inflow of considerable rivers; of great marshes once themselves greater lakes; of seamed and bent and broken lava plains, and all elevated 5,000 or 6,000 feet above the sea. Out of its western rim flow Rogue and Klamath rivers, which make their way directly through all intervening mountain barriers to the Pacific ocean 200 miles away. Here are also the springs of the Sacramento, which courses the greatest valley of California and finds its way to the sea through the Golden Gate, 500 miles to the south.

This brief description of the topography of the State will, perhaps, prepare the reader's mind to understand the peculiar geological conditions and changes that have marked the different portions of the State better than he otherwise could. He will also see why a description of our part of Oregon is not a description. of another part either as to soil, climate, or production.

In general it may be said that the mountain ranges of Oregon are volcanic upheavals; the mighty bending upward of the crust of the earth's surface when its inborn fires were lashed to unwanted fury in some stormy age of old eternity. The western valleys, and especially Willamette, were doubtless formed by this upheaval of its enclosing ranges, leaving the floor of the surface here comparatively undisturbed. This really rests on a foundation of aqueous rock of unmeasured thickness, on which the alluvial matter which forms its soils has been deposited. With this there are, in many places, deep deposits of water-worn pebbles and stratified sand, which were made at an era much more modern than that of the underlying sandstone. These water-marked deposits are clearly traced in the eroded banks of the rivers, and in the cloven face of some of the mountains of the Coast Range, and on the western slopes of the