Geology and Mineralogy. 133 



texts, but we do not find them here as the title " College Physi- 

 ography " would lead us to suppose. The illustrations, the bibliog- 

 raphy, "and the descriptive matter are therefore the only new 

 points of interest. The bibliography includes a nearly complete 

 list of the chief physiographic papers in English, as well as a 

 number of foreign papers. Its usefulness would have been in- 

 creased by bracketed references in the text. In its present form 

 and for the college student it is little more than a long list of 

 references of very unequal value. However, from the teacher's 

 standpoint it is useful to have the list in printed form. 



The chief contribution of the authors consists of much new and 

 highly useful descriptive matter. To point out a few illustra- 

 tions : The positions of the magnetic poles and related subjects, 

 the variations of Alaskan glaciers, and the nature of sea ice. 

 The general character of the book would have been enhanced by 

 less rather than more reference to the influence of physiographic 

 features upon man. The relationships pointed out are nowhere 

 full enough to be either clear or convincing, and are very unequal 

 in value. They should have been organized about a body of dis- 

 tinct principles and really analyzed, not left as mere suggestions, 

 loose in application and doubtful in character. 



11. Deposits of the Useful Minerals and Rocks, by Betschlag, 

 Vogt, and Krusch. Translated from the original German text 

 by S. J. Tkuscott. In three vols., Vol. I ; 8° ; pp. 514 ; figs. 

 219 ; 1914 (Macmillan and Co.). — It is a very excellent thing that 

 this great work should have been translated into English and thus 

 made accessible to a much wider circle of those who, either from 

 theoretical or practical reasons, or both, are interested in all that 

 pertains to ore deposits. This first volume deals with the subject 

 of ore-deposits in general, then takes up magmatic segregations, 

 contact-deposits, and passes on to lodes, irregular cavity-fillings, 

 and metasomatic deposits, under which tin and quicksilver are 

 considered, at which point the present volume closes. A special 

 feature is the great number of illustrative examples cited, usually 

 with maps and diagrams, so that a very comprehensive view of 

 the best known ore occurrences is obtained. Under several head- 

 ings the student will find in condensed form the substance of the 

 notable papers published by Vogt in the " Zeitschrif t fur praktische 

 Geologie " on the origin of certain classes of ore deposits, especially 

 by magmatic segregation, on the concentration of the metallic 

 elements, etc., etc. 



The subject of classification is thoroughly discussed, a good his- 

 torical review being presented ; the one furnished by the authors 

 is that primarily of mode of occurrence, the chief groups being : 



I, Magmatic segregations; II, Contact-deposits; III, Cavity-fill- 

 ings and metasomatic deposits ; IV, Ore-beds. The secondary 

 divisions under these are chiefly of a chemical nature ; thus under 



II, we find: a Oxide ores, Iron group, and b, Sulphide ores, Lead- 

 zinc and copper group. Of course by this method III is a very 

 great division with 19 sub-divisions and comprises a large pro- 

 portion of all the important deposits. 



