CENTRAL AND EASTERN NEVADA. 337 



clinal, the abrading foi'ces having acted with more effect upon the upturned 

 edges of the strata than upon their flanks. In the bottom, both above and 

 below the bend, are large springs of cold water. Through this north fork 

 and the south fork of Big Creek Canon, which have an easy, natural grade, 

 a road has been built, crossing the divide between them, at an altitude of 

 8,922 feet. 



Opposite this divide is the highest point of the western ridge. Big Creek 

 Peak, (10,265 feet,) whose upheaval is probably one phase of the lateral fold 

 observed at Santa F^ as it marks the angle of a change of direction in the 

 strikes of the rocks forming the western ridge. Its summit and eastern slopes 

 are in the slate, while on its western flanks is a body of limestone correspond- 

 ing to that on the eastern side of the range. In the siliceous slates forming 

 the very summit of this peak were found some traces of fossil remains, so much 

 metamorphosed, however, as to be unrecognizable. To the north the slates 

 appear to bend in direction somewhat to the westward, having a strike of 

 about north, and a westward dip of 45°, of which a section is afforded by the 

 Big Creek Canon below the forks, while beyond Big Creek the direction of 

 the strata changes gradually to the eastward, assuming the prevailing strike 

 of the ridge north of this, about north 35° east, and still preserving a westward 

 dip of 40° to 45°. 



At the mouth of Big Creek Canon is a small body of rhyolite, which 

 forms the bed-rock of the canon for a short distance, and extends along the 

 lower foot-hills for a couple of miles to the southward; it is a very character- 

 istic variety — a reddish-purple rock, of granitoid structure, containing crystals 

 of quartz and mica. It seems to be an isolated eruption, and not accompanied 

 by any extensive disturbance of the surrounding rocks, though, on the north 

 side of the canon mouth, it is bordered by a breccia, containing fragments of 

 the adjoining slates and limestones. On the south side of the canon the rock 

 has an earthy and somewhat decomposed texture and brick-red color, probably 

 resulting from solfataric action, of which the traces are still visible in the warm 

 spring in the bed of the canon just above the town. This brick-red variety 

 was formerly used as refractory material in the construction of furnaces built 

 here, during the early developments of the district, for smelting the galena 

 43 



