66o REVIEWS 



Economic Geology oj the United States. By Heinrich Ries, A.M., 

 Ph.D. New York: Macmillan Co., 1905. Pp. 435, 25 plates, 

 97 figures. 

 To say that this work is designed as a textbook will give a general 

 idea of its nature. The arrangement is somewhat different from that of 

 other works on this subject, in that the non-metaUic minerals are discussed 

 first. The reason assigned is that the non-metallic are more important 

 and their deposits simpler. The order of treatment is: Part I, "Coal; 

 Petroleum, Natural Gas, and Other Hydrocarbons; Building Stones; 

 Clay; Lime and Calcareous Cements; Salines; Gypsum; Fertilizers; 

 Abrasives; Minor Minerals; Water; Soils and Road Materials;" Part II, 

 "Ore Deposits; Iron; Copper; Lead and Zinc; Gold and Silver; Silver- 

 Lead; Aluminum, Manganese, and Mercury; Minor Metals." 



E. W. S. 



Structural Features oj the Joplin District. By C. E. Siebenthal. 

 (Economic Geology, Vol. I, No. 2, November- December, 1905, 

 pp. 119-28.) Discussion by H. Foster Bain. (Ibid., pp. 

 172-73.) 

 This paper is of especial interest in that it shows a way in which incor- 

 rect conclusions may be drawn as to the throw of faults. Throws of 150 

 feet or more have been described for the Joplin district. Shale is found 

 in horizontal juxtaposition with limestone strata whose normal position 

 is 150 feet below. These conditions vary much in short distances, and 

 the author accounts for them by showing (i) that the shale is uncon- 

 formable on the limestone and was laid down on an uneven erosion sur- 

 face; (2) that solution and the giving way of roofs of caverns have let 

 blocks of strata down; and (3) that there has been faulting of much less 

 throw. E. W. S. 



Geological Survey oj North Dakota. Third Biennial Report. By 



A. G. Leonard and Assistant Geologists. Bismarck, 1904. 



Pp. 217, 33 plates, 8 figures, 2 maps. 



This work contains articles on "Lignite on the Missouri, Heart, and 



Cannon Ball Rivers, and its Relation to Irrigation;" "Report on the 



Region between the Nothern Pacific Railroad and the Missouri River;" 



"Topography of North Dakota;" "Geological Formations of North 



Dakota;" "Methods of Stream Measurements;" "The Run-off of the 



Streams in North Dakota." E. W. S. 



