EAST HUMBOLDT EANGE. 531 



So thick a series of limestones overlying- a pure quartzite can be noth- 

 ing else than the Wahsatch limestone, and it is not surprising that the only 

 fossils obtained are Coal-Measure forms, procured high up in the series. 

 The quartzite is referred to the Ogden Devonian, and the section of beds 

 seems to repeat that of the Piiion Range in the same latitude, with the 

 exception that the limestone series is here continued much liigher ; the 

 latter, in the Pitlon Range, being eroded off down to the beds, which cor- 

 respond to the Helderberg horizon in the New York State section, and which 

 rise here in the Humboldt Range, 5,000 feet higher, embracing doubtless 

 the narrow belt of Sub-Carboniferous and the enormous development of 

 Lower Coal-Measure limestones. 



The lower section, C — D, at the bottom of the geological sheet, cuts 

 the Humboldt Range at I'r^mont's Pass, where only the upper members 

 of the Wahsatch limestone are represented on the east side, lying steeply 

 inclined against the granite. On the west slope, however, the Ogden 

 Quartzite is shown resting next the granite, but without any overlying rock. 



It is noteworthy that in this heavy and elevated limestone mass run- 

 ning streams are entirely wanting. The water, however, reaches the sur- 

 face along the base of the range in numerous springs extending from East- 

 ing's to Fremont's Pass. These springs supply Ruby Lake. They are all 

 clear, cold waters, with temperatures varying from 43° to 48°. Cave 

 Spring, about 6 miles to the south of Fremont's Pass, runs a considerable 

 stream, coming out directly from the limestone through an opening suffi- 

 ciently large to admit a man into an interior lake-chamber 10 by 12 feet 

 and 10 feet in height. A narrow winding channel connects this chamber 

 with still ajiother and larger one beyond, with its limestone floor covered 

 with water. It is worthy of exploration, but, so far as known, has never 

 yet been visited. 



Not far north of Cave Spring occurs the only outburst of volcanic 

 rocks observed in this portion of the range, and is of some special interest, 

 as both macroscopically and microscopically it resembles a trachyte, and 

 has been classed as such, although by no means a typical variety. Break- 

 ing through the limestone, which is considerably shattered, it forms a low, 

 irregular hill of rough, gray rock with a medium compact texture. The 



