FOUNTAIN HEAD HILLS. 521 



low, crescent-shaped ridge of the northern portion of the Fountain Head 

 Hills is made up of quartzite beds, which have been assigned to the Weber 

 Quartzite. Owing to the gentle slopes of these hills and the low angle at 

 which the rocks lie, no considerable section of the beds was obtained. In 

 them is a large development of a peculiar quartzitic sandstone or grit, 

 which is very persistent through the Northern Nevada region, and consid- 

 ered characteristic of the horizon of the Weber Quartzite. It is a more or 

 less fine-grained, reddish-gray rock, made up of angular fragments of flint 

 and chert of various colors, in which black and red generally predominate, 

 with a matrix of a granular siliceous material, often stained by brown oxide 

 of iron and containing a very large amount of limpid quartz. It has a pecu- 

 liarly rough feel, suggesting a porous texture, almost like that of a volcanic 

 rock. It effervesces slightly under acids, and, under the microscope, is seen 

 to contain small crystals of calcite, the matrix being made up of crypto-crys- 

 talline grains and rounded fragments of quartz. The structure of this ridge 

 is, as far as can be seen, that of a gentle anticlinal, whose axis runs with the 

 trend of the ridge. 



Southeast of the quartzite occurs a body of limestone, extending south- 

 ward as far as Cedar Pass. It appears to be made up of long ridges, vary- 

 ing much in direction, but with a general trend of northeast and southwest. 

 One of the main ridges indicated a strike of north 25° to 30° east. The 

 strata consist of heavy beds of grayish-blue earthy limestone, occasionally 

 highly metamorphosed and in places impregnated with seams of white cal- 

 cite. On Euclid Peak, the culminating point, the beds lie nearly hori- 

 zontal, but have a slight western dip, and along their eastern base show 

 outcrops of dark quartzite, which have been referred to the Weber forma- 

 tion. Fragments of this quartzite may be traced cropping out above the 

 Tertiary and Quaternary beds, along the foot-hills from Euclid Peak to 

 Cedar Pass, where it rises in ridges several hundred feet in height. Toward 

 the pass, the structure is somewhat complicated, and the quartzite north 

 of Indian Well, where the beds have undergone the greatest change in 

 course, is seen striking north 60° to 65° west, with a dip of 12° to 16° E. 

 Here the quartzite, a hard compact rock, is traversed, in a striking manner, 

 by numerous narrow veins of pure quartz, but apparently of no economic 



