84 BIBLIOGRAPHY AND INDEX OF N. A. GEOLOGY; [bull. 162. 
710 Smyth [0. H., jr.]. Report on the talc industry of St. Lawrence 
County [New YorkJ. 
N. Y., 15th Ann. Kept. State Geologist, vol. i, pp. 20 and 661-671, 1897; 
N. Y. State Mus. 49th Ann. Rept., vol. ii, pp. 661-671, 1898. 
Describes occurrence and characteristics of talc in this county. 
720 Weathering of alnoite in Manheim, New York. 
Geol. Soc. Am., Bull., vol. ix, pp. 257-268, pi. 18; Reviews: Am. Geol., 
vol. xxii, pp. 382-383 (£ p.); Am. Nat., vol. xxxii, p. 535 (f p.), 1898. 
Abstract, Jour, of Geol., vol. vi, pp. 331-332, 1898. 
Describes occurrence and petrographic and chemical characters of 
the rock. 
721 The New York talc industry in 1897. 
The Mineral Industry, 1897, pp. 630-631, 1898. 
Includes brief notes on the occurrence of talc. 
722 Spaulding (M. B.). The Silver Pick mine, Wilson [Colorado]. 
School of Mines Quart., vol. xx, pp. 41-47, 1898. 
Describes the general geologic features of Mt. Wilson and the occur- 
rence of the gold ores. 
723 Spencer (Arthur Coe). The geology of Massanutten Mountain in 
Virginia. 
Published by the author, Washington, D. C, 54 pp., 3 pis., 1 fig., 1897; 
Review by H. S. Williams, Am. Jour. Sci., 4th ser., vol. v, pp. 231-232 
(| p.) ; Review by C. R. Keyes, Am. Geol., vol. xxi, pp. 191-192, 1898. 
Describes the occurrence and character of the Silurian and Devonian 
formations, the geologic structure, physiographic features, and geologic 
history of the region. 
724 The Upper Cretaceous section in southwestern Colorado. 
Abstract, Science, new ser., vol. vii, p. 143 (^ p.), 1898. 
Contains summary of paper read before the Geological Society of 
Washington. 
725 and Grirty (G. H.). The Devonian in southwestern Colorado. 
Science, new ser., vol. vii, p. 810 (| p.), 1898. 
Contains summary of paper read before the Geological Society of 
Washington. 
720 Spencer (J. W.). Great changes of level in Mexico and the inter- 
oceanic connections. 
Geol. Soc. Am., Bull., vol. ix, pp. 13-34, pis. 1-5, figs. 1-6; Review by 
W. M. Davis, Science, new ser., vol. vii, p. 203 (£ p.), 1898. 
Describes the physical features of Mexico, the occurrence and char- 
acter of the Lafayette, Columbia, and Coatzacoalcos formations and 
the evidence of recent changes of level. 
727 Another episode in the history of Niagara River. 
Abstracts : Am. Assoc. Adv. Sci., Proc, vol. xlvii, p. 299 (|-p.) ; Science, 
new ser., vol. viii, pp. 501-502 (£ p.); Am. Geol., vol. xxii, pp. 259-260 
(| p.), 1898. 
