528 DESCEIPTIVE GEOLOGY. 



SECTION IV. 



EAST HUMBOLDT RANGE. 



BY ARNOLD HAGUE. 



Region south of Fremont's Pass. — The East Humboldt is not only 

 the main range of Central Nevada, but is also the most prominent uplift 

 lying between the Sierra Nevada of California upon the one side and the 

 "Wahsatch of Utah upon the other. It extends from the southern limit of 

 the map northward to the Humboldt Eiver, a distance of 80 miles. It is a 

 bold, single ridge, having a trend of about north 18° to 20° east, with many 

 rugged summits reaching over 10,000 feet above sea-level. Mount Bon- 

 planJ, the highest peak, a fine commanding point, at the northern end of 

 the range, attains an elevation of 11,321 feet. The range, from its position 

 and relative elevation, presents in its physical conditions much more of an 

 alpine aspect, receiving at the same time a larger supply of moisture, in the 

 form of both snow and rain, than any other of the Basin ranges. Its flora 

 also suggests the higher elevations, the long slopes and glacier-carved 

 canon-basins being covered with scattered forests, including several varie- 

 ties of pines and firs ; Pinus flexilis would appear to be the prevailing spe- 

 cies. The trees, however, are too short, being rarely over 50 feet in height, 

 and too knotty to afford much valuable timber. 



In general terms, the geological structure of the Humboldt Range rep- 

 resents a mass of Archaean rocks, which acts as the axis of an anticlinal fold, 

 striking obliquely across the range, from which are inclined the Devonian 

 and Carboniferous strata, resting unconformably upon the granites and 

 gneisses of the crystalline foundation. The southeast side of the fold 

 extends from the region of Fremont's Pass to Hasting's Pass, and consists 

 of a single series of limestones conformably underlaid by quartzites, the 

 latter appearing along the western base, while the entire summit and 

 eastern face presents only heavy massive limestone. The eastern slope is 



