Correspondence. 257 
The formation of sandstone concretions, G. P. Merrill. Proc. LT. S. 
Nat. Museum, vol; 17. pp. 88-89, pi. 6, L894. 
Notes on the invertebrate fauna of the Dakota formation, with des- 
criptions of new moll use an forms, C. A. White. Proc. U. S. Nat. Mu- 
seum, vol. 17. pp. 131-138, pi. 7, 1894. 
Ancient myriapods, (i. F. Matthew. Canadian Record of Science, 
pp. 93-99, April. 1894. 
Historical sketch of the discovery of mineral deposits in the Lake Su- 
perior region, H. V. Winchell. Second Ann. Rept. of the Proc. of the 
Lake Superior Mining Institute: 46pp., 1804. 
A review of the fossil flora of Alaska, with descriptions of new spe- 
cies. F. H. Knowlton. Proc. I". S. Nat. Museum, vol. 17, pp. •207-240, 
pi. 9, 1894. 
Geology of the Cripple creek gold mining district. Colorado, Whitman 
Cross. Proc. Colorado Sci. Soc, June 4, 1804: 18 pp. 
The ore deposits of Cripple creek, Colorado. R. A. F. Penrose. Jr. 
Proc. Colorado Sci. Soc, June 4, 1894; 5 pp. 
A classification of economic geological deposits based on origin and 
original structure. W.O. Crosby. Technological Quarterly, vol. 7. pp. 
27-48, April. 1894. 
The origin of parallel and intersecting joints, W. <). Crosby. Tech- 
nological Quarterly, vol. 6, pp. 230-236, Oct., 1893. 
The new geological cross sections of Keweenaw point, L.L. Hubbard. 
Second Ann. Kept, of the Proc. of the Lake Superior Mining Institute; 
18 pp., 1894. 
The hydro-geology of the upper Mississippi valley and of some of the 
adjoining territory, D. W. Mead. Journ. of the Association of Engi- 
neering Societies, vol. 13, No. 7. pp. 330-386, July. 1894. 
Description of some Cincinnati fossils. S. A. Miller and C. L. Faber. 
Journ. of the Cincinnati Soc. of Nat. Hist., vol. 17. No. '■'>. pp. 137-158, 
pis. 7 and 8. Oct., 1894. 
V. Proceedings of Scientific Laboratories, etc. 
The Kansas University Quarterly, vol. "2, No. 1, July. 1894, contains: 
Vertebrate remains from the lowermost Cretaceous. S. \V. Williston: A 
new turtle from the Benton Cretaceous. S. W. Williston: Notes on ('//<- 
tacrinus socialis Grinnell, B. H. Hill: Restoration of Platygonus, S. W. 
Williston: A chemical examination of the wa'ters of the Kaw river and 
its tributaries, E. H. S. Bailey and E. C. Franklin. 
CORRESPONDENCE. 
Note <>n the Geological Map ok the State ok New York. In the 
"Twelfth Annual Report of the State Geologisl lor the year 1892," Al- 
bany, 1893, we read at p. 28, that in the geological map published in 
1842, i>.\ the Geological Survey, "no attempt was made m represent the 
age and relations of certain of the formations on the easl side of the 
Hudson river." (>n the con i rary. all the i in thousand copies distrib- 
