330 KEMP'S ORE DEPOSITS. 



NEVADA. 



2.11.12. Geology. Nevada lies almost entirely in the Great 

 Basin, only the western portion being in the Sierras. The surface 

 is thus largely formed by the dried basins of former great lakes, 

 principally Lakes Lahontarr and Bonneville. A large number of 

 ranges extend north and south through the State, known collec- 

 tively as the Basin ranges. They have been formed by block tilt- 

 ing on a grand scale and present enormously disturbed strata. 

 The geological sections exposed are of surpassing interest (cf. Ex- 

 ample 36), and show Archaean and Paleozoic in great thickness. In 

 these mountains are found the mining districts, while between 

 them lie the alkaline plains. 1 



2.11.13. Lincoln County is in the southeastern corner and con- 

 tains a number of small mining districts. The ores are in general 

 silver-lead ores in limestone, or veins with sulphuret ores in quartz- 

 ite and granite. Pioche is one of the principal towns, near which 

 is found the once famous and now reopened Raymond & Ely 

 mine. A strong fissure cuts Cambrian quartzite and overlying 

 limestone, where the latter has not been eroded, and is occupied 

 by a great porphyry dike. Along the contact between the por- 

 phyry and the wall rock the chutes of ore have been found. Mr. 

 Ernest Wiltsee, at the Montreal meeting of the American Insti- 

 tute of Mining Engineers, February, 1893, described and figured 

 the Half Moon mine, on this same great fissure, where the quartz- 



1876, p. 55. B. Silliman, "Report on the Mining District of Arizona near 

 the Rio Colorado," Amer. Jour. Sci., ii., XLI. 289; see also Engineering 

 and Mining Journal, Aug. 11, 1877, p. 111. Raymond's Reports, and 

 those of the Director of the Mint. 



1 J. Blake, "The Great Basin," Proc. Cal. Acad. Sci., IV. 275, Amer. 

 Jour. Sci.j iii., VI. 59. W. P. Blake, "On the Geology and Mines of Ne- 

 vada" (Washoe silver region), Quar. Jour. Geol. Sci., Vol. XX., p. 317. 

 H. G. Clark, "Aurora, Nev.: a Little of its History, Past and Present," 

 School of Mines Quarterly, III. 133. G. K. Gilbert, "A Theory of the 

 Earthquakes of the Great Basin, with a Practical Application," Amer. 

 Jour. Sci., iii., XXVII. 49. I. C. Russell, "Geology end History of Lake 

 Lahontan, a Quaternary Lake of Northwestern Nevada." Monograph XL, 

 U. S Geol. Survey ; also Third Ann. Rep. Director U. S. Geol. Survey, 

 195. C. D. Walcott, " Paleontology of the Eureka District," Mononraph 

 VIII., U. S. Geol. Survey. Gilbert, Wheeler, Lockwood, and others, 

 " Eastern Nevada: Notes on its Economic Geology," WJieeler's Survey, 

 Rep. Prog., 1869, 71, 72 ; also Vol. III. and Supplement. For further lit- 

 erature, see under Example 36. 



