174 BIBLIOGRAPHY OF NORTH AMERICAN GEOLOGY, 1906-1907. 
Smyth, Henry Lloyd. 
2254. The relations between gold and pyrite. — Min. and Sci. Press, vol. 93, 
pp. 58-59, 4 figs., July 14, 1906. 
Discusses the relations between pyrite and gold in ore-bearing veins. 
2255. Magnetic observations in geological and economic work. I. — Econ. 
Geology, vol. 2, no. 4, pp. 367-379, 5 figs., June, 1907. 
Snedaker, J. A. 
2256. Copper mines in Colorado. — Eng. and Min. Jour., vol. 83, pp. 817-818, 
April 27, 1907. 
Solorzano, M. M., and Hobson, Bernard. 
2257. Plant remains in basalt, Mexico. — Geol. Mag., dec. 5, vol. 4, no. 5, 
pp. 217-219, 1 pi., May, 1907. 
Sovereign, L. Douglas. 
2258. Valuable crystals and rare minerals of San Diego County, California. — 
Min. World, vol. 23, no. 19, pp. 521-522, November 11, 1905. 
Spandel, Erich. 
2259. Die Foraminiferen des Permo-Carbon von Hooser, Kansas, Nord 
Amerika. — Saecular-Feier der Naturhistorisehen Gesellschaft in Niirnberg, 1801- 
1901, Festschrift, pp. 175-194, 10 figs., [1901]. 
Spencer, Arthur Coe. 
The magmatic origin of vein-forming waters in southeastern Alaska. — Am. 1 
Inst. Min. Eng., Trans., vol. 36, pp. 364-371, 1906 (Bi-Mo. Bull. no. 5, pp. 971- 
978, 1905).— See Spencer, 17, page 315 of Bulletin no. 301, U. S. Geol. Survey. 
The origin of vein-filled openings in southeastern Alaska. — Am. Inst. Min. 
Eng., Trans., vol. 36, pp. 581-586, 3 figs., 1906 (Bi-Mo. Bull. no. 6, pp. 1211-1216, 
3 figs., 1905).— See Spencer, 18, page 315 of Bulletin no. 301, U. S. Geol. Survey. 
2260. What is a fissure vein? — Econ. Geology, vol. 1, no. 3, p. 286, December- 
January, 1905-1906. 
2261. The Juneau gold belt, Alaska.— U. S. Geol. Survey, Bull. no. 287, pp. 
1-137, 34 pis. (incl. maps), 37 figs., 1906. 
Describes the geography, the general geology and geologic structure, the occurrence, 
character, relations, and origin of the ore deposits, the associated minerals, and the - 
economic developments. 
2262. Magnetite deposits of the Cornwall type in Berks and Lebanon 
counties, Pa.— U. S. Geol. Survey, Bull. no. 315, pp. 185-189, 1907. 
Discusses more particularly the occurrence and origin of the iron ores. 
Spencer, Joseph William Winthrop. 
2263. [Report on] Niagara Falls and Niagara district. — Canada Geol. Sur- 
vey, Sunim. Rept. for 1905, i>]». 87-91, 190(5. 
Gives various data in regard to Niagara Falls. 
2264. The Jamaica earthquake. — Abstract: Science, new ser., vol. 25, pp. 
966-967, June 21, 1907. 
2265. Recession of the Niagara Falls. — Geol. Mag. dec. 5, vol. 4, no. 10, 
pp. 440-441, October, 1907. 
2266. The Falls of Niagara, their evolution and varying relations to the 
Great Lakes; characteristics of the power and the effect of its diversion. — 
Canada, Geol. Survey, 1907. 400 pp., 43 pis., 30 figs., 1 map. 
