BIBLIOGRAPHY OF NORTH AMERICAN GEOLOGY, 1906-1907. 1G3 
Riihl, Alfred. 
2099. tiberblick liber die geographischen und geologischen A'erhaltnisse 
Alaskas. — Petermann's Mitteilungun, Band 53, Heft 1, pp. 1-16, 1907. 
Gives a general account of the physiography and geology of Alaska. 
Ruhm, H. D. 
2100. Phosphate mining in Tennessee. — Eng. and Min. Jour. vol. 83, pp. 
522-526, 5 figs., March 16, 1907. 
Describes briefly the origin and distribution of the Tennessee phosphate deposits. 
Russell, Israel G. 
2101. Drumlin areas in northern Michigan. — Michigan Acad. Sci., 7th Rept., 
i»i». :;<;~:rr. 1905. Abstract: Geol. Soc. America. Bull., vol. 16, pp. 577-578, 1906. 
2102. Physiographic problems of to-day. — Congress of Arts and Science, Uni- 
versal Exposition. St. Louis, 1904. vol. 4, pp. 027-649, 1900. 
2103. Memoir of William Henry Pettee.— Geol. Soc. America, Bull., vol. 16, 
pp. 558-560, 1906. 
2104. The surface geology of portions of Menominee, Dickinson, and Iron 
counties, Michigan. — Michigan, State Board of Geol. Survey, Rept. for 1906, 
pp. 7-91, 12 pis., 1 rig., 1907. 
Describes the topography, drainage, and glacial geology of the region. 
2105. Concentration as a geological principle. — Geol. Soc. America, Bull., 
vol. 18, pp. 1-28, 1907. 
Discusses the various methods by which concentration is effected. 
2106. Drumlins of Michigan. — Abstract: Geol. Soc. America, Bull., vol. 17, p. 
707, 1907. 
Ruth ven, A. G. 
2107. An ecological survey in the Porcupine Mountains and Isle Royale, 
Michigan. — Michigan State Board of Geol. Survey, Ann. Rept. for 1905, pp. 
17-47, 14 figs., 1906. 
Includes a brief account of the geology of the region. 
Rutledge, J. J. 
2108. Davis pyrites mine, Massachusetts : a unique deposit and some unusual 
methods of mining. — Eng. and Min. Jour., vol. 82, pp. 673-676, 724-728, 772- 
775, illus., 1906. 
Includes a brief account of the geology and the occurrence of the ores. 
Sachs, A. 
2109. Der Kleinit, ein hexagonales Quecksilberoxychlorid von Terlingua in 
Texas.— K. preussischen Akad. d. Wiss., Sitzb., no. 52, pp. 1091-1094, 1905. 
Describes the characters and composition of kleinite from Terlingua, Texas. 
2110. Notiz zu der chemischen Zusammeasetzung des Kleinits. — Centralbl. 
f. Mineral., pp. 200 202. 1906. 
Describes tin 1 chemical composition of kleinite from Terlingua, Texas. 
2111. Zinnoberkristalle aus Sonoma County in Kalifornien; Gips- und Kalk- 
spatkristalle von Terlingua in Texas.— Centralbl. f. Mineral., pp. 17-19, 1907. 
Describes the cryslallographic characters of minerals from California and Texas. 
Sadtler, Benjamin. 
2112. Gold and tin in northwestern Black Hills. — Min. World, vol. 24, no. 17, 
Pp. 520 522, 5 tigs., April 28, 1906. 
