Author's Catalogue. 393 
Seely, Henry M. 
Sketch of the life and work of Augustus Wing. (Am. GeoL, vol. 28, 
p. I, July, 1501, portrait.) 
Turner, H. W. 
The Esmeralda formation, a fresh water lake deposit in Nevada. 
(21 Ann. Rep., U. S. Geol. Sur., 1898-1899, Part 2, pp. 197-208, 1900.) 
Upham, Warren 
The Toronto and Scarboro drift series. (Am. GeoL, vol. 28, pp. 306- 
318, Nov. 1901.) 
Van Hise, C. R. 
The geology of ore deposits (I). (Science, N. S., vol. 14, pp. 745- 
757, Nov. 15, 1901.) 
Van Hise, C. R. 
The iron-ore deposits of the Lake Superior region. (21 Ann. Rep., 
U. S. G. S., Part 3, pp. 305-434, pls. 48-59, 1901.) 
Walcott, C. D. 
Twenty-first annual report of the United States Geological Survey 
to the Secretary of the Interior, 1899-1900. In seven parts. Washing- 
ton, 1900. 
Willmott, A. B. 
The Michipicoten Huronian area. (Am. Geol., vol. 28, p. 14, July, 
1901.) 
Woodworth, J. B. 
The history and conditions of mining in the Richmond coal basin, 
Virginia. (Trans. Am. Inst. Min. Eng., Feb., 1901.) 
Wortman, J. L. 
Studies of Eocene mammalia in the Marsh collection. (Am. jour. 
Sci., vol. 12, 4th Ser., Nov., igoi, pp. 377-382.) 
CORRESPONDENCE. 
When was the Mississippi River Valley Formed? The age of 
the Mississippi river seems to be sometimes a question. On the flood 
plain and along the bluffs at Clinton and Davenport, Iowa, and at 
numerous other places are deposits of the Carboniferous like the un- 
der clay of the Illinois coal fields, evidently remnants of the lower 
coal formation which was deposited and then swept away by the river 
when an elevation occurred. The town plot of Clinton is filled with 
these pits, which arc uncovered in making foundations. Some deep 
pits were excavated in making the foundations for the Rock Island 
government works some years ago. 
Prof Hall in the first volume of Iowa geological reports noticed 
this, and gave some figures. One was shown in a quarry at Rock 
