74 BIBLIOGRAPHY AND INDEX OF N. A. GEOLOGY, [bull. 162. 
613 Pearce (Richard). [Telluride ore from Sierra Blanca, Colorado]. 
Colo. Sci. Soc, Bull., No. 6, pp. 4-6, 1898. 
Gives chemical analyses of the material and remarks on the indications 
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614 Peary (Robert E.). Northward over the great ice: A narrative of 
life and work along the shores and upon the interior ice cap 
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Frederick A. Stokes & Co., New York, 2 vols., 1898. Review by T. C. 
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615 Peckham (S. F.). The genesis of bitumens, as related to chemical 
geology. 
Am. Phil. Soc, Proc, vol. xxxvii, pp. 108-139, 1898. 
616 Penfield (S. L.). See Brush (George J.), No. 114. 
617 [On krennerite from Cripple Creek, Colorado.] 
See Chester (A. H.), No. 150. 
618 On pearcite, a sulpharsenite of silver, and on the crystalliza- 
tion of polybasite. 
Colo. Sci. Soc, Proc, vol. v, pp. 210-224, 1898. 
Describes the chemical and crystallographic characters of pearcite 
and the crystallographic characters of polybasite. 
619 and Foote (H. W.). On clinohedrite, a new mineral from 
Franklin, N. J. 
Am. Jour. Sci., 4th ser., vol. v, pp. 289-293, 4 figs., 1898. 
Describes the crystallographic and chemical characters of the mineral. 
620 Penhallow (D. P.). [Eeview of a On the genus Lepidophloios as 
illustrated by specimens from the coal formation of Nova 
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Am. Nat., vol. xxxii, pp. 464-465, 1898. 
621 Penrose (R. A. F., jr.). [Geology and its relations to topography.] 
Am. Soc. Civil Engrs., Trans., vol. xxxix, p. 86 (f p.), 1898. 
In discussion of paper by John C. Branner on the same subject. 
622 The ore deposits of Cripple Creek [Colorado]. 
Colo. Sci. Soc, Proc, vol. v, pp. 50-53, 1898. 
See Bibliography and Index for 1896, No. 543. 
623 Perrine (Charles D.). Earthquakes in California in 1896 and 1897. 
U. S. Geol. Surv., Bull., No. 155, 47 pp., 1898. 
624 Perry (J. H.). The physiography of Worcester, Mass. 
Review by W. M. Davis, Science, new ser., vol. vii, pp. 850-851 (£ p.), 
1898. 
625 Petre (R. W.). Mines of La Plata Mountains, Colorado. 
Eng. and Mg. Jour., vol. lxvi, pp. 667-668, 2 figs., 1898. 
Describes the general geology of the region and the occurrence of 
the precious metals. 
