BATTLE MOUNTAINS. 671 



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Battle Mountains, referred to the Carboniferous, although with some hesita- 

 tion, as it lies so near the western limit of the Carboniferous formations. 



Along the eastern foot-hill, the beds are traversed by a number of inter- 

 esting mineral veins, which have been worked. extensively in previous years. 

 There would appear to be two distinct mineral belts, the one rich in argen- 

 tiferous galena, with associated products of decomposition, together with 

 some zinc and antimonial minerals, while the other is characterized by cop- 

 per-bearing minerals, chiefly red and black oxides of copper, carrying some 

 native metal. Blue carbonate and silicate of copper may also be recognized. 



The volcanic outbursts of the Battle Mountains occupy a compara- 

 tively small area, but are represented both by rhyolites and basalts, break- 

 ing out both along the foot-hills, where the sedimentary strata rise abruptly 

 out of the plain, and, what is somewhat exceptional, in the centre of the 

 uplift, shattering and displacing the older Palaeozoic ridges. Rhyolite, as 

 in the broad area to the south, is the prevailing rock, and is also of the same 

 normal type which characterizes the Fish Creek and Augusta Mountains. 

 The most interesting locality is found on the west side of Willow Canon, 

 where it forms a broad table-topped ridge, showing precipitous walls toward 

 the canon, with no evidences of flow or bedding, and on the summit of the 

 ridge no signs of domes or bosses, as is seen in the Fish Creek Mountains. 

 The face of the canon- wall presents a rather uniform appearance, with only 

 the marked shadings and variations in color so characteristic of rhyolitic 

 eruptions. In habit, the rock exhibits a compact microfelsitic structure, and 

 in places develops a tendency to a lithoidal texture ; in color, reddish-gray 

 and pink are the prevailing tints, with irregular masses of a deeper pur- 

 plish-red. Individualized minerals, with the exception of quartz, which 

 occurs in large, broken, translucent fragments, are rare ; the feldspars are 

 nearly all fragmentary. 



On the west slopes are one or two outbursts of rhyolite in the lime- 

 stone, which would appear to be along a line of fissure parallel with the 

 strike of the beds. The rock difi^ers in no way from that already described. 

 At the northeast corner of the Battle Mountains, a group of irregular rhy- 

 olite hills rises several hundred feet above the Humboldt River. They 

 present but little of special interest either in structure or lithological aspect 



