420 REVIEWS 



the kaolin. The presence of oxidized and kaoHnized garnet gneiss at a 

 depth of 85 feet is equally suggestive of the derivation of the kaolin 

 from a superficial source. A summary statement of these two hypotheses 

 to explain the origin of kaolin deposits is given, but the writer has no 

 definite basis for deciding between them. The shattered zone of quart- 

 zite in which the kaolin occurs has a known width of 1,000 feet and a 

 length of 7,000 feet. This kaolinitic quartzite rock can be easily crushed 

 and is suitable for making silica brick of the ganister type or the kaolin 

 can be washed from the crushed material and the quartz used for siHca 

 sand. 



North of the kaolin locality a number of graphite deposits have 

 been opened along the contacts of pegmatite, pyroxene granite, syenite, 

 and Grenville limestone. The ore consists of aggregates of orthoclase, 

 woUastonite, diopside, scapolite, and graphite. These relations and 

 associations of minerals indicate that this material was formed by the 

 interaction of emanations from the igneous intrusions and the limestone. 



J. F. W. 



Map of the North Pacific. By W. E. Johnson. U.S. Coast and 

 Geodetic Survey, Map No. 3080, North Pacific Ocean; scale 

 1:20,000,000; dimensions 14 by 41 inches. Price 25 cents. 

 A new base map of the North Pacific Ocean on the transverse 

 polyconic projection has been prepared by W. E. Johnson, Cartographer, 

 of the U.S. Coast and Geodetic Survey of the Department of Commerce, 

 and is now available for distribution. This system of projection was 

 devised by Ferdinand Hassler, who was the organizer and first Superin- 

 tendent of the U.S. Coast and Geodetic Survey. This projection was 

 computed and constructed by C. H. Deetz, Cartographer, U.S. Coast 

 and Geodetic Survey. 



The Mogollon District, New Mexico. By Henry G. Ferguson. 

 Bulletin 71S-L, United States Geological Survey, Government 

 Printing Office, Washington, D.C., 1921. Pp. 34, pis. 6, figs. 2. 



The Mogollon (Mo-go-yohn) or Cooney district lies in southwestern 

 New Mexico, about fourteen miles from the Arizona line. The district 

 was discovered in 1875, when James Cooney found rich silver-copper 

 ores there. Since then the mines have yielded about $16,000,000 worth 

 of ores (estimated to 191 7). 



The topography is generally very rugged, especially on the eastern 

 edge of the district, which lies along the Mogollon Range. The rocks are 



