396 The American Geologist. December, 1900 
Penck, Albert. 
Observations made on a Tour in Canada. (Proc. Can. Inst., vol. ?, 
Read March 16, i8q8.) 
Pent ield, S. L. 
Chemical composition of turquois. (Am. Jour. Sci., vol. 10, pp. 346- 
350, Oct., 1900.) 
Pirsson, L. V. 
Petrography of the igneous rocks of the Little Belt Mountains. (20th 
Ann. Rep., U. S. G. S., Part 3, pp. 463-581, pis. 70 to -]■].) 
Prosser, C. S. 
Classification and distribution of the Hamilton and Chemung series 
of central and eastern New York. Part 2. (51st report, N. Y. State 
Mus., vol. 2, pp. 65-327, 1899. 
Prosser, C. S. (and R. B. Rowe.) 
Stratigraphic geology of the eastern Helderbergs. (51st report N 
Y. State Mus., vol. 2, pp. 331-3541 1899-) 
Prosser, C. S. 
The Shenandoah limestone and Martinburg shale. (Jour. Geol., vol. 
8, pp. 655.663, Oct. -Nov., 1900.) 
Ries, Heinrich. 
Limestones of New York and their economic value. (51st report N. 
Y. State Mus., vol. 2, pp. 355-467- 1899. 
Ries, H. 
Clays and shales of Michigan, their properties and uses. (Vol. 7, Ge- 
ol. Sur. Mich., pp. 1-67, 4 pis. 1900.) 
Rowe, R. B. (C. S. Prosser and) 
Stratigraphic geology of the eastern Helderbergs. (51st report N. Y. 
State Mus., vol. 2, pp. 331-354, 1899-) 
Russell, I.e. 
A preliminarv paper on the Geology of the Cascade mountains in 
Washington, (20th Ann. Rep. U. S. G. S., Part 7, pp. 83-210, pis. 8- 
20.) 
Schrader, F. C. 
A reconnoissance of a part of Prince William Sound and the Copper 
River District, Alaska, in 1898. (20th Ann. Rep., U. S. G. S., Part 7, 
pp. 341-423. pis. 22-35. 
Smith, W. S. Tangier. 
A topographic study of the islands of southern California. (Bull. 
Dept. Geol., Univ. Cal. , vol. 2. pp. 179-230- Sept., 1900.) 
Smyth, C. H., Jr. 
Report on the crystalline rocks of the western Adirondack regions. 
(51st report N. Y. State Mus. vol. 2, pp, 469-497.) 
Sollas, W. J. 
Evolutional Geology. (Science, vol. 12, pp. 725-756, Nov. 16, 1900.) 
Spurr, J. E. 
A reconnoissance in southwestern Alaska in 1888. (20th Ann. Rep., 
U. S. G. S., Part 7, pp. 31-264, pis. 7-13.) 
