150 BIBLIOGRAPHY OF NORTH AMERICAN GEOLOGY, 1906-1907. 
Phalen, William Clifton — Continued. 
1921. Clay resources of northeastern Kentucky. — IT. S. Geol. Survey, Bull, 
no. 385, pp. 411-416, 1906. 
Describes the occurrence and character of coal measures and recent clay beds, and the 
composition of the clays. 
1922. Coal resources of Johnstown, Pa., and vicinity. — TT. S. Geol. Survey, 
Bull. no. 316, pp. 20-41, 1 pi., 1907. 
Phalen, W. C, and Martin, Lawrence. 
1923. Clays and shales of southwestern Cambria County, Pa. — TJ. S. Geol. 
Survey, Bull. no. 315, pp. 344-354, 1907. 
Philippi, E. 
1924. Ueber junge Intrusionen in Mexiko und ihre Beziehungen zur Tek- 
tonik der durchbrochenen Sehichtgesteine, nach den Forschungen von E. Bose 
und C. Burckardt— Centralbl. f. Mineral., pp. 449-460, figs., 1907. 
Discusses phenomena attendant upon intrusions as exemplified in Mexico. 
Phillips, William B. 
1925. Terlingua quicksilver district [Texas]. — Min. AVorld, vol. 23, pp. 
259-260, 1905. 
Describes the general geology and the occurrence of the ores. 
1926. Quicksilver deposits of Terlingua district, Brewster County, Texas. — 
Am. Min. Cong., 8th Ann. Sess., pp. 184-193, 1906. 
Includes notes on the geology of the district and adjacent regions of Texas. 
Pickering", William H. 
1927. Lunar and Hawaiian physical features compared. — Am. Acad. Arts 
and Sciences, Mem., vol. 13, no. 4, pp. 151-179, 16 pis., 1906. 
Contains data in regard to volcanic craters upon the Hawaiian Islands. 
1928. The place of origin of the moon — the volcanic problem. — Jour. Geol- 
ogy, vol. 15, no. 1, pp. 23-38, 4 tigs., 1907. 
Piers, Harry. 
1929. Economic minerals of Nova Scotia. Catalogue and description of a 
collection at the Provincial Exhibition, Halifax. Revised Edition. 60 pp. — In 
Kept, of the Dept. of Mines, Nova Scotia, for 1906, Halifax, 1907. 
Pilsbry, H. A. 
1930. PlanorMs alabamensis and dilatatus in the Floridian Pliocene. — 
Nautilus, vol. 19, no. 3, p. 34, July, 1905. 
Proposes the name PlanorMs alabamensis avus for a Pliocene form differing from the 
recent form. 
Pirsson, Louis V. 
1931. Samuel Lewis Penfield [obituary]. — Am. Jour. Sci., 4th ser., vol. 22, 
pp. 353-367, 1 pi. (port.), November, 1906. 
Includes a list of his papers. 
1932. [Obituary notice of] Israel Cook Russell. — Am. Jour. Sci., 4th ser., 
vol. 21, p. 481, June, 1906. 
1933. Angelo Heilprin. — Am. Jour. Sci., 4th ser., vol. 24, p. 284, September, 
1908. 
The texture of igneous rocks. — See Cross, Iddings, Pirsson, Washington, 
no. 608. 
Pirsson, Louis V., and Washington, Henry S. 
1934. Contributions to the geology of New Hampshire: No. II, Petrography 
of the Belknap Mountains. — Am. Jour. Sci., 4th ser., vol. 22, pp. 439-457, 493- 
514, 1900. 
