254 KEMP'S ORE DEPOSITS. 



often pierce them. Tertiary coals are recorded from several local- 

 ities in the archipelago in the southern part. The Aleutian Isl- 

 ands mark a long stretch of volcanic eruptions. W. H. Dall has 

 given a general section of the banks of the Yukon River from 

 the British boundary to the delta. There are, in rough order from 

 east to west, granite, talcose slates, and Azoic rocks, 150 miles ; 

 sandstone and conglomerate, 250 miles ; shales with one small coal 

 seam, 75 miles ; blue slate, conglomerate, eruptive rocks, slate, 

 eruptive rock, blue slate, and black sandstone, 325 miles ; blue 

 sandstone, slate, trap, blue and black slate, volcanic rock, to the 

 northwest mouth. The interior is largely composed of tundras, or 

 great plains of moss and other plants, frozen into perpetual ice at 

 a depth of a foot or so. These hide the geology. Doubtless the 

 slates of the upper waters have supplied the gold, which is rich in 

 some of the river gravels. On the Aleutian Islands some brown 

 Miocene sandstones are seen (Shumagin), and granite and meta- 

 morphic rocks. 1 



2.13.04. Example 46. Douglass Island. A dike or boss of 

 granite 400 feet wide, piercing slates regarded as Triassic by G. M. 

 Dawson, and impregnated (i.e., the granite) with auriferous pyrites. 

 This enigmatical ore body is thought by Dawson to be the upper 

 part of a granite dike. It consists in great part of a mass of 

 quartz, feldspar, calcite, and pyrite, in which are buried the so- 



1 " Alaska as a Mining Territory," Engineering and Mining Journal, 

 June 27, 1885, p. 444. "Mineral and Agricultural Wealth of Alaska," En- 

 gineering and Mining Journal, Aug. 24, 1887, p. 134. T. A. Blake, Rep. 

 on the Geol. of Alaska, Ex. Doc. No. 177, Fortieth Congress, New Series, 

 p. 314, Washington, 1868. W. H. Dall, "Explorations in Alaska," Amer. 

 Jour. Sci., ii., XLV. 96. Rec. "Notes on Alaska and the Vicinity of 

 Bering Straits," Ibid., iii., XXI. 104. " Notes on Alaska Tertiary Deposits, 

 Geological Section of the Shumagin Islands," Ibid., iii., XXIV. 67. " Alaska 

 and its Resources," Washington, 1870. Rec. "Glaciation in Alaska," 

 Bull Phil. Soc., Vol. VI., p. 33, Washington, 1884. G. H. Dawson, " Re- 

 port on the Yukon District in 1887," Geol. Survey of Canada, 1887-88, 

 Vol. III., Part B, pp. 14B-18B, 154B-156B. H. W. Elliot, "Our Arctic 

 Provinces," p. 163, New York, 1887. E. J. Glave, "Pioneer Packhorses 

 in Alaska," The Century, September and October, 1892. R. G. McConnell, 

 "Glacial Features of Parts of the Yukon and Mackenzie Basins," Geol. 

 Soc. of Amer., I., p. 540. I. C. Russell, " The Surface Geology of Alaska," 

 Geol. Soc. of Amer., I., p. 99. E. R. Skidmore, "Alaska," Rep. Director 

 of the Mint, 1883, p. 17, and 1884, p. 17. J. Stanley-Brown, " Auriferous 

 Sands at Yakutat Bay, Alaska," Nat. Geog. Mag., Vol. III., 1891. 



