76 BIBLIOGRAPHY AND INDEX OF N. A. GEOLOGY, [bull. 135. 
439 Pavlow (A.). [Classification of Pleistocene deposits.] 
Int. Cong. Geol., Coinpte Rendu, 5th session, pp. 195-196. 
Discusses the principles of chronologic and genetic classification. 
440 Peale (Albert 0.). Natural mineral waters of the United States. 
U. S. Geol. Surv., 14th Ann. Rept., pt. 2, pp. 51-88. 
Gives a definition of mineral water, discusses its origin, the source 
of mineralization, and its geologic and geographic distrihution and 
gives a list of American mineral spring resorts. 
441 Livingston to the Snake Plains. Itinerary, Bozeman to Butte, 
Mont. 
Int. Cong. Geol., Coinpte Rendu, 5th session, pp. 365-367. 
Describes the geology of the route traversed by the Rocky Mountain 
excursion between these points. 
441a The Paleozoic section in the vicinity of Three Forks, Mon- 
tana. With petrographic notes by G. P. Merrill. 
Abstract : Am. Geol., vol. xiv, p. 394 (J p.). 
Noticed in Bibliography and Index for 1892 and 1893. 
441 1) Pearce (Kichard). The occurrence of gold in ores of the Cripple 
Greek district [Colorado]. 
Abstract: Eng. and Mg. Jour., vol. lvii, p. 271. 
Noticed in Bibliography and Index for 1892 and 1893. 
442 Peckham (S. F.). On the origin of bitumens; a retrospect. 
Am. Jour. Sci., 3d ser., vol. xlviii, pp. 389-395. 
Gives an account of observations in different parts of the United 
States on the occurrence of petroleum and bitumen, and concludes that 
they have not had a uniform derivation, and discusses the probability 
of their distillation by metamorphic action. 
443 Petroleum in southern California. 
Science, vol. xxiii, pp. 74-75. 
Gives a historical sketch of the development of the petroleum indus- 
try in California, and presents a section showing the succession of 
strata in certain wells. 
443& Peet (C. E), Salisbury (R. D.) and. Surface geology. Drift 
phenomena of the Palisade ridge. 
N. J. Geol. Surv., Rept. for 1893, pp. 157-224. 
See Salisbury (R. D.) and Peet (C. E.), No. 493. 
444 Penfield (S. L.). Contributions to the crystallization of willemite. 
Am. Jour. Sci., 3d ser., vol. xlvii, pp. 305-309. 
Abstract : Am. Nat., vol. xxviii, pp. 873-874 (i p. ). 
Describes the crystal! ographic characters and cleavage of willemite 
from New Mexico. 
445 On the crystallization of herderite. 
Am. Jour. Sci., 3d ser., vol. xlvii, pp. 329-339. 
Abstracts: Am. Geol., vol. xiii, p. 427 (8 1.); Am. Nat., vol. xxviii, 
p. 871 (J p.). 
Describes the characteristics of herderite from five localities in 
Maine. 
