IV ADVERTISEMENT. 



PP 36. The lead, zinc, and fluorspar deposits of western Kentucky, by E. O. TJlrich and W. 8. Tangier Smith. 1905. 



218 pp., 15 pis. 

 fP 38. Economic geology of the Binghrtm mining district of Utah, by J. M. Boutwell, with a chapter on area! geology, by 



Arthur Keith, and an introduction on general geology, by S. F. Emmons. 1906. 413 pp., 49 pis. 

 PP 41. The geology of the central Copper River region, Alaska, by W. C. Mendenhall. 1905. 

 B 254. Report of progress in the geological resurvey of the Cripple Creek district, Colorado, by Waldnar Lindgren and 



F. L. Ransome. 1904. 36 pp. 



B 255. The fluorspar deposits of southern Illinois, by H. Foster Bain. 1905. 75 pp., 6 pis. 

 B 256. Mineral resources of the Elders Ridge quadrangle, Pennsylvania, by R. W. Stone. 1905. 85 pp., 12 pis. 

 B 257. Geology and paleontology of the Judith River beds, by T. W. Stanton and J. B. Hatcher, with a chapter on the 



fossil plants, by F. H. Knowlton. 1905. 174 pp., 19 pis. 

 PP 42. Geology of the Tonopah mining district, Nevada, by J. E. Spurr. 1905. 295 pp., 24 pis. 



Correspondence should be addressed to 



THE DIRECTOR, 



UNITED STATES GEOLOGICAL SURVEY, 



WASHINGTON, D. C. 

 SEPTEMBER, 1905. 



