SILVER AND GOLD, CONTINUED. 227 



are known in the neighborhood of the ores both in Utah and in the 

 Nacemiento copper district of New Mexico. From what we know 

 of ore deposits in general this seems most probable. 1 



ARIZONA. 



2.11.06. G-eology. Arizona lies partly in the plateau region 

 and partly in the Great Basin. The Basin ranges converge with 

 the Rocky Mountains, which, however, are chiefly in New Mexico. 

 The uplands of the ranges are well watered and covered with 

 timber, but the low-lying portion of the Great Basin is an arid 

 desert, and in southwestern Arizona is the hottest part of the United 

 States. Cretaceous and Jura-Trias largely form the plateau 

 region. Running southeast to northwest is the great development 

 of Carboniferous limestone so often referred to under " Copper," 

 and underlying this are found Archaean granites, gneisses, etc. A 

 great series of ore deposits is ranged along this contact. In the 

 southwest are mountains of granites and metamorphic rocks. The 

 Territory also contains vast flows of igneous rocks, and in the pla- 

 teau country between the converging ranges some 20,000 or 25,000 

 square miles are covered by them. The Grand Canon of the Colo- 

 rado has laid bare a magnificent geological section of many thou- 

 sand feet, from the Archaean to the Tertiary. 8 



1 F. M. F. Cazin, " The Origin of the Copper and Silver Ores inTriassic 

 Sand rock," Engineering and Mining Journal, Dec. 11, 1880, p. 381 ; April 

 .30, 1881, p 300. " The Silver Sandstone Formation of Silver Reef," Ibid., 

 May 22, 1880, p. 351 , Jan. 10, 17, 24, 1880, pp. 25, 48, 79 (Roth well). A. N. 

 Ja kson, " Silver in Sedimentary Sandstone," Rep. Director of Mint, 1882, 

 p. 384, reprinted from Cal. Acad. Sci. J. S. Newberry, " Report on the 

 Properties of the Stormont Silver Mining Company," etc., Engineering 

 and Mining Journal, Oct. 23, 1880, p. 269. "The Silver Reef Mines," 

 Ibid., Jan. 1, 1881, p. 4. C. M. Rolker, " The Silver Sandstone District of 

 Utah," M. E., IX. 21. 



2 "Central Arizona," Engineering and Mining Journal, April 23, 

 1881, p. 285. "Colorado River of the West," review of Ives Expedition, 

 Amer. Jour. Sci., ii., XXXIII. 387. G. F. Becker, Tenth Census, Vol. 

 XIII., p. 44. C. E. Dutt jn, " Th.e Physical Geology of the Grand Canon 

 District," abstract of Monograph II., Second Ann. Rep. Director U. S. 

 Geol. Survey, 49-161 ; see also the monograph. Patrick Hamilton, The 

 Resources of Arizona, A. L, Bancroft & Co., San Francisco, 1884. B. Silli- 

 man, " Report on Mining Districts of Arizona, near the Rio Colorado," En- 

 gineering and Mining Journal, Aug. 11, 1877, p. Ill ; taken from Amer. 

 Jour. Sci., ii. XLI. 289. C. D. Walcott, "Permian and Other Paleozoic 



