Geology. 507 



Hence, tan (Leah) — 16 ~^y 26 _ y^ _ 4.5 = 0*599019 



2^/26 + 8 

 and Leah = 30° 55' 21". 



Therefore, in this special case, the error amounts to nearly one 

 degree. It may be remarked, in conclusion, that we have worked 

 out an analytical expression, for the general case, connecting 

 Leah with A cab and found that this function is not satisfied by 

 putting L cab = 3(Lcah). 



II. Geology. 



1. Publications of the United States Geological Survey ; 

 George Otis Smith, Director. — Recent publications of the U. S. 

 Geological Survey are noted in the following list (continued from 

 p. 62, Jan., 1912) : 



Topographic Atlas. — Sixty-five sheets. 



Folios. — No. 178. Foxburg-Clarion Folio, Pennsylvania ; by 

 E. W. Shaw and J. M. Munn. Pp. 17 ; columnar section, 4 

 topographic and geologic maps. 



No. 179. Pawpaw-Hancock Folio. Maryland-West Virginia- 

 Pennsylvania ; by George W. Stose and Charles K. Swartz. 

 Pp. 24 ; 3 topographic and geologic maps ; 20 half tone views. 



No. 180. Claysville Folio, Pennsylvania ; by M. J. Munn. 

 Pp. 14 ; sections, 4 topographic and geologic maps. 10 figures. 



No. 181. Bismarck Folio, North Dakota ; by A. G.Leonard. 

 Pp. 8 ; 1 topographic, 1 geologic map. 



Mineral Resources of the United States. Calendar year 

 1910. Part I.— Metals. Pp. 796 ; 1 plate, 9 figures. Part II.— 

 Nonmetals. Pp. 1005 ; 17 plates, 10 figures. The individual 

 chapters of this invaluable compilation have already been issued 

 in advance. 



Bulletins. — No. 470. Contributions to Economic Geology 

 (Short Papers and Preliminary Reports), 1910. Part I. — Metals 

 and Nonmetals except Fuels. C. W. Hayes and Waldemar 

 Lindgren, Geologists in Charge. Pp. 558 ; 17 plates, 64 figures. 



No. 485. A Geologic Reconnaissance of the Iliamna Region, 

 Alaska ; by G. C. Martin and F. J. Katz. Pp. 138 ; 9 plates, 

 20 figures. 



No. 493. Results of Spirit Leveling in Illinois, 1909, 1910 ; R. 

 B. Marshall, Chief Geographer. Pp. 115 ; 1 plate. 



No. 494. The New Madrid Earthquake ; by Myron L. 

 Fuller. Pp. 119 ; 10 plates, 18 figures. 



No 496. Results of Triangulation and Primary Traverse for 

 the Years 1909 and 1910. R. B. Marshall. Chief Geographer. 

 Pp. 392 ; 2 plates. 



No. 497. A Reconnaissance of the Jarbridge, Contact, and 

 Elk Mountain Mining Districts, Elko County, Nevada ; by F. C. 

 Schrader. Pp. 162 ; 26 plates, 3 figures. 



