62 BIBLIOGRAPHY OF NORTH AMERICAN GEOLOGY, 1906-1907. 
Day, David T. 
694. Black sands of the placer mines of the United States. — 59th Cong., 
1st Sess., Sen. Doc. no. 65, pp. 8-15, 1905. 
695. The auriferous black sands of California. — Mines and Minerals, vol. 27, 
no. 12, pp. 564-565, July, 1907. 
696. Black sands of the Pacific coast. — Franklin Inst., Jour., vol. 164, no. 2, 
pp. 141-153, August, 1907; Min. World, vol. 27, pp. 891, 974, 1013, 1907. 
Mineral resources of the United States, calendar year, 1905. — See U. S. Geo- 
logical Survey, no. 2418. 4 
The production in the United States in 1906 of platinum. — See no. 2419. 
Day, David T., and Richards, R. H. 
697. Investigation of the black sands from placer mines. — U. S. Geol. Sur- 
vey, Bull. no. 285, pp. 150-164, 1906. 
Presents in tabular form the results of the examination of black sands from the 
Pacific slope and from various placer mining districts, and describes concentration ex- 
periments. 
Mineral resources of the United States, 1905: black sands. — See no. 2418. 
Dean, Bashford. 
698. Dr. Eastman's recent papers on the kinship of the Arthrodires. — Sci- 
ence, new ser., vol. 26, pp. 46-50, July 12, 1907. 
Deckert, Emil. 
699. Die Vulkanausbruche von Martinique und St. Vincent. — Frankfurter 
Vereins f. Geogr. und Statist ik, Jahresb.. 66-67, pp. 153-156, 1903. 
Describes volcanic eruptions on the, islands of Martinique and St. Vincent. 
De Kalb, Courtenay. 
700. Secondary enrichment upward. — Min. and Sci. Press, vol. 93, p. 176, 
August 11, lf)06. 
Describes an instance of secondary enrichment in copper deposits north of Lake Huron. 
701. Do the geological relations of ore deposits justify the retention of the 
law of the apex?— Econ. Geology, vol. 1, no. 8, pp. 801-809, 1906. 
702. Geology of the Exposed Treasure lode, Mo.jave, California. — Am. Inst. 
Min. Eng., Bi-Mo. Bull., no. 13, pp. 15-24. 3 figs., January. 1907. 
Describes the lithology, the geologic structure, the periods of faulting, and the forma- 
tion of the ores. 
De Lury, Justin S. 
703. Cobaltite occurring in northern Ontario, Canada. — Am. Jour. Sci., 
4th ser., vol. 21, pp. 275-276, 1 fig., April, 1906. 
Describes the occurrence and characters of the crystals. 
Demming, Henry C. 
704. Report of the mineralogist. — Pennsylvania Dept. Agric, 10th Ann. Rept., 
pp. 438-440, 1905. 
Gives notes on mineral resources of Pennsylvania. 
705. Report of the geologist. — Pennsylvania Dept. Agric, 10th Ann. Rept., 
pp. 459-462, 1905. 
Includes notes upon the geology and mineral resources of Pennsylvania. 
706. Report of the mineralogist. — Pennsylvania Dept. Agric, 11th Ann. 
Rept., pp. 447-451, 1906. 
Gives notes upon mineral resources of Pennsylvania. 
707. Report of the geologist. — Pennsylvania Dept. Agric, 11th Ann. Rept., 
pp. 451^54, 1906. 
Includes notes upon the economic resources of Pennsylvania. 
