Oregon is truly an uneven and mountainous country. It is true that in passing from the dividing ridge westward, there are a few situations where the traveler views the country around him as apparently level, but this appearance continues on advancing along, but a short distance, till he is plunged into almost inextricable gulfs and deep ravines. The Blue mountains or intermediate range between the dividing ridge and the Cascade range, are of minor importance. They traverse no considerable extent of country, nor are they very wide. They have a volcanic appearance, and are strewd over with vescicular lava.
The Cascade range of mountains are more extensive, traversing by different names the whole of Oregon and California, at a distance of from 100 to 200 miles from the Pacific ocean. Some of its peaks are high and coverd with perpetual glaciers. This range, like the dividing ridge, seems to have been elevated by compression.
Between the Willamet valley and the ocean, is a range of high hills calld the Coast range. These are too rugged to admit of cultivation.
The western shore of Oregon is rocky, and in many places precipitous. If the theory that ocean beds are formd by undulations in the earth’s crust be true, the query might arise, Why are ocean limits of precipitous rocks of the firmest material, as is the case with many of the ocean shores, and not a gradual slope from the land downward to the bed of the ocean? If it be admitted that rivers are formd by the expansive force of gasses acting beneath the earth’s crust, it may be supposd that a fissure by similar means may be formd parallel and near to the shore of an ocean, so that its waters by their weight may produce a subsidence of that portion lying under them, whilst that part opposite the fissure remaind stationary.
Oregon may be regarded as a primary country. Few fossiliferous rocks are seen in any part of it. I noticd on the west bank of Big Sandy creek, about thirty miles west of South pass, a few fossiliferous shale rocks. I have not noticd any in other places, though they may exist sparingly. From the American falls on Snake river, for several hundred miles westward the country is overlaid with a stratum of basaltic lava. This seems to be the true basalt, and although the rocks of the Willamet river at Oregon city have been considerd by some as basalt, from their extreme hardness, yet I have noticd that the surface of those rocks, after having been exposd to the weather, become a mere sand rock, by the loss of the iron with which they are impregnated. It is well known to mineralogists, that iron becomes soluble by the action of the atmosphere upon it, by which means water carries it from its parent bed to lower levels, where it is deposited, under the name of bog ore. The rocks at Oregon city consist of about three varieties of rock, differing not essentially in their properties, though some of them appear to have been subjected to so high a degree of heat as to render them somewhat crystaline or vitreous. The rocks at Oregon city are so fully impregnated with iron, that the magnetic needle, at some points along these rocks, is drawn aside from its polar position.