544 TE VIEDVIZES, 
Andesite : 
Hornblende-andesite, tuff or breccia. 
Fine grained hypersthene-andesite. 
South of Campbell Peak in the canyon of Fall River, is a dike-like 
mass of fragmental andesite. This is exposed in the bed of the river, 
and it extends vertically up the sides of the canyon. In the dike 
material are embedded the fragments of fossil wood (sequoia) It is 
clear that this dike represents a fissure opened by an earthquake (?) 
and filled in by the fragmental andesite from above. 
Meadow Valley in the northeast corner represents a depressed area, 
the result of faulting in early Pleistocene time. During a portion of 
the Pleistocene, this valley was occupied by a lake. 
On the northeast slope of Spanish Peak ridge are fine moraines, 
and evidences of glacial action were found also at many other points. 
The lowest elevation which sheltered on its north slope a glacier dur- 
ing the glacial period, is the ridge southwest of Buck’s Valley. At one 
point what appeared to be a morainal pond had been formed by a small 
glacier. The top of the ridge south of this pond has an elevation of 
only 5800 feet. As a general rule it may be said that in the Sierra 
Nevada, all those slopes which now shelter snow banks during the 
entire season, nourished glaciers during the glacial period. 
Structure.— A figure is introduced into the text, showing the 
general parallelism of the schistosity to the granitic masses, which 
represent intrusions into the schistose rocks. It will be noted, how- 
ever, that narrow tongues of the granitic rocks at some points cut 
directly across the schistosity, and it appears probable that the schistos- 
ity in the main was developed at a period antecedent to the granitic 
intrusions and that the parallelism of the lines of schistosity to the 
contact of the entering granite, is due to these masses being forced 
aside by the intrusive rock, the separation of the schistose masses tak- 
ing place most readily parallel to the schistosity. There is evidence 
of faulting on an extensive scale in the northeast portion of the quad- 
rangle to the east of Spanish Peak, and faulting was noted at the 
head of Dogwood Creek. A photograph of this fault scarp is repro- 
duced on the illustrations sheet. 
Economic geology.— Yhe economic features of the district include a 
description of the gold vein deposits, and of manganese, iron, chromite 
and lime and marble deposits. While quartz is the ordinary vein 
material of the gold deposits, one instance of an auriferous barite vein 
is noted. 
