78 BIBLIOGRAPHY AND INDEX OF N. A. GEOLOGY, Ibull.135. 
454 Phillips (William B.). On the phosphate rock of Tennessee. 
Ala. Iud. Sci. Soc, Proc., vol. iv, pp. 44-48. 
Gives a brief description of the phosphate rock and its chemical 
analysis. 
454ft Piatt (W. H. II.), Haworth (E.) and. A geologic section along 
the Verdigris Kiver from the State line to Madison [Kans.]. 
Kans. Univ. Quart., vol. ii, pp. 115-118. 
See Haworth (E.) and Piatt (W. H. H.), No. 257. 
455 Pirsson (L. V.). On the crystallization of enargite. 
Am. Jour. Sci., 3d ser., vol. xlvii, pp. 212-215. 
Abstracts: Am. Geol., vol. xiii, p. 359 (5 1.); Am. Nat., vol. xxviii, 
p. 870 (i p.). 
Describes the crystallographic characters of enargite from the Ida 
and National Belle mines of Colorado. 
450 On some phouolite rocks from the Black Hills. 
Am. Jour. Sci., 3d ser., vol. xlvii, pp. 341-346. 
Abstract: Am. Nat., vol. xxviii, pp. 702-703. 
Describes the chemical and petrographic characters of phonolite, 
from the Black Hills. 
456ft The geology of Conanicnt Island, Rhode Island. 
Abstract : Am. Nat., vol. xxviii, pp. 420-421 (^ p. ). 
Noticed in Bibliography and Index for 1892 and 1893. 
457 and Wells (H. L.). On the occurrence of leadhillite from 
Missouri, and its chemical composition. 
Am. Jour. Sci., 3d ser., vol. xlviii, pp. 219-226. 
Describes the occurrence, crystallographic characters, and chemical 
composition of leadhillite. 
458 Pollard (0. L.). [Note on fossil leaves from Great Neck, Long 
Island, N. Y.] 
N. Y. Acad. Sci., Trans., vol. xiii, pp. 180-181. 
Note on the occurrence of fossil leaves in the Cretaceous on Long 
Island, N. Y. 
459 Poole (Henry S.). The Picton coal field; a geological revision. 
Nova Scotian Inst. Sci., Proc. and Trans., 2d ser., vol. i, pp. 227-343, 
with geologic map and sections. 
Describes several faults which occur in this district and the lith- 
ologic character of the Cambro-Silurian, Silurian, Devonian, Car- 
boniferous, and Permian beds, and gives the sections exposed in a num- 
ber of coal mines. 
459« Posada (Juan de la 0.). The geology of Oarmelo Bay [California]. 
See Lawson (A. C. ), No. 352. 
4(30 Posepny (F.). The genesis of ore deposits. 
Am. Inst. Mg. Engrs., Trans., vol. xxiii, pp. 197-369, figs. 1-100. 
Reviews the general facts and theories concerning the origin of ore 
deposits, describes the constitution and effects of underground circu- 
lating waters, the character of ore deposits occurring in fissures and 
in soluble rocks, those occurring in distinctly stratified rocks and in 
crystalline schists and eruptive rocks, and those formed by chemical 
and mechanical influences of the surface region. Advocates the ascen- 
sion theory of the formation of ore deposits. 
