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138 University of California Publications. [Geology 



and numerous earth movements, a cause is not hard to find a 

 priori. But some exact evidence exists that shows an eastward 

 tilting of the region, with a differential elevation of certain crust 

 blocks. From the point that juts eastward just south of Carson, 

 to Empire, a well-cut stream cliff extends almost interruptedly. 

 It is best preserved on the south limits of Carson (see pi. 26b). 

 The turn eastward occurs within the town, and there are yet 

 found several low cliffs and terraces, as if the river had varied 

 its course on the big turn to the east. A short distance south of 

 Carson, on the toe of the eastward trenching ridge, a typical 

 river deposit has been cut at an_ elevation of 4,900 feet (see pi. 

 27a). South of here the alluvium of the valley has masked all 

 traces of the stream. West of Prison Hill is a low divide sep- 

 arating Eagle and Carson valleys, quite similar in nature and 

 origin to the low divide in AVashoe Valley. The valley west of 

 Prison Hill is the narrowest portion of the valley south of Lake- 

 view. It lies between two prominent fault-blocks, the recent 

 movements of which are surely the cause of formation of the low 

 divide. Evidence of elevation is present on both blocks, and is 

 best shown on the eastern one. From a little distance Prison Hill 

 exhibits a white band or apron on the lower western slope, that 

 is in striking contrast to the dark metamorphic rocks above. This 

 white deposit slopes up from the valley level at the Prison to a 

 point west of the summit. The material is granitic sand, of 

 either fluviatile or lacustrine origin. On the west side of the val- 

 ley an exactly similar feature is not found, but the same sort 

 of material is found to nearly the same elevation. The recent 

 alluvial apron along these hills has smoothed all irregularities 

 and covered all masked features. South of Clear Creek, how- 

 ever, the river or lake deposits are much in evidence, and show 

 some terrace-like effects. There are three terraces gravel-covered, 

 and quite prominent in the field, but not sufficient work has yet 

 been done to warrant a full statement regarding their genesis. 

 The lower two are probably due to stream erosion, and the up- 

 per, because of its connection with the fault-block south of Clear 

 Creek, is probably due to faulting. That there was some terrac- 

 ing by the older Carson River is shown by the effects in Carson. 

 The highest terrace, northwest of Cradlebaugh Bridge, were it 



