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GEOLOGY OF OREGON AND WASHINGTON.
187

basaltic rock conceals from sight the record we have referred to, except where by the action of water the pages of the book have been cut through from cover to cover—from ocean-bed to overlying basalt.

For a distance of sixty miles east of Dalles this last overflow may be traced, growing thinner and thinner, until it becomes a mere capping on the hills. Underneath it all is sedimentary, except the interruptions, several in number, of the older outflows of lava. It is owing to the large extent to which volcanic ash enters into the composition of the earth and soil of this portion of Oregon and Washington that both earth and water are so often strongly alkaline. It forms a soil inexhaustible in fertility, and particularly adapted to the growth of cereals; but, owing to its elevation, and to the depth of the stream below the surface, together with a dry climate, is difficult of adaptation to the uses of the agriculturist.

Mr. J. Wessen, in an article published some years since in the Overland Monthly, thus speaks of the geological formation of the high plateaux and the lake region of Southeastern Oregon:

"Coming from the northeast, the Blue Range of Oregon, the Cascade Range from the north, and the Sierra from the south, blend into or form a vast steppe or table-land of lava and sagefields, interspersed with a score of lakes, in size varying from five to forty miles in length, and proportionate width. This high separating belt of land and water commences at the Owyhee River and extends westward to the mountains, running at right angles to the ocean—a length of three hundred miles, and an average breadth of one hundred and fifty. There are three distinct chains of lakes in this district: The eastern, known as the Warner, inclusive of the Harney and Malheur. The second chain of lakes may be called the Goose Lake, including its northern links,—Albert, Silver, and other smaller lakes. Goose Lake nestles in the extreme north end of the Sierra, and is the source of Pitt River, the main branch of the Sacramento. This fact has been disputed, owing, perhaps, to the outlet being underground in the drier seasons. The third and last, and larger of the several chains, is the Klamath, embracing Wright and Rhett Lakes, farther south. The Warner Lakes string along more like a river; and the rapid current, setting north at all