LOWER TEUCKEE VALLEY. 817 



SECTION IX. 



TEUCKEE EIVEE EEGION. 



BY ARNOLD HAGUE. 



Lower Truckee Valley. — The broad valley of the Truckee lyiug- 

 between "Wadsworth Station and Pyramid Lake, and hemmed in by the 

 Truckee and Virginia Ranges, is formed of a series of horizontal arenaceous 

 beds, through which alternate strata of more or less argillaceous material. 

 These beds always present an undisturbed position, and are seen to rest 

 unconformably on the basaltic hills, which enclose the valley to the east- 

 ward. Upon the west side, a short distance back from the river, they are 

 overlaid by a deposit of Quaternary, which rises to the foot-hills of the 

 Virginia Range, and thickens toward the mountain-flank. 



Where the shallow lateral stream- valleys, as of Berkshire Canon and the 

 canon that comes down from Ormsby Peak, are most deeply eroded into 

 the Quaternary, the top of the horizontal sand series is clearly seen. 

 Through these beds, the Truckee River, in flowing north, has cut out a 

 caiion from 200 to 300 feet deep, exposing the series, which are observed to 

 possess a dip of not over 2° toward Pyramid Lake, a dip altogether that of 

 deposition. In the photograph reproduced in Plate XXIV, a view taken 

 about 3 miles below the town of Wadsworth, these bluff's, which un- 

 doubtedly belong to the ago of the Humboldt Pliocene, are character- 

 istically shown, with the more indurated beds standing out prominently 

 beyond the friable sands. The same illustration presents a fair view 

 of the valley, with exceptionally large and fine trees along the river-banks, 

 the flood-plain of the river varying from 100 to 2,000 feet in width. For 4 

 or 5 miles below Wadsworth, there is a fluviatile Quaternary formation 

 about one-half mile in width, below which there are two or three other 

 basins where the canon is quite broad, and which are occupied as farms. 



At an elevation of 100 or 200 feet above the uppermost limit of the 



Pliocene strata, there may be traced along the basaltic flanks of the 

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