Essentials for the Microscopical Determination of 

 Rock-Forming Minerals and Rocks 



By ALBERT JOHANNSEN 



Profeator of Petrology 

 The University of Chicago 



A laboratory manual designed to provide students of petrology and geologists 

 interested in petrology with information on methods of determining microscopically 

 the points of separation between similar minerals and their modes of occurrence. 



This valuable volume contains, in addition to a folding alphabetical list so 

 placed that reference may be made to it without turning pages, the following 

 important features: "A Quantitative Mineralogical Classification of Igneous 

 Rocks" ; "A Summary of Petrographic Methods" ; "Modes of Occrurence of Various 

 Minerals"; "Rules for Computing Rocks from Their Modes"; and "Names Pro- 

 posed for Various Families." 



Cloth; $2.00, postpaid $2.10 



THE UNIVERSITY OF CHICAGO PRESS 



CHICAGO - ILLINOIS 



Second Edition: Revised and Enlarged 



Source Book for the Economic 

 Geography of North America 



By CHARLES C. COLBY 



Associate Professor of Geography 

 in the University of Chicago 



The fundamental idea of this book is to make available to the busy teacher the 

 material on this subject which is scattered widely through literature. The course which 

 has been given for a number of years at the University of Chicago has resulted in the 

 collection and organization of the material most suitable for the purpose. 



The book contains short magazine articles and materials from Canadian, Mexican, 

 and United States government publications. The selection of the material has been 

 governed by the concept that there is a direct relation between the environment and 

 the economic activities of the region. The author aims to survey the dififerent sections 

 of the country from the viewpoint of industrial opportunity. 



With chapter and maps on Alaska Cloth, $3.00, postpaid $3.10 



THE UNIVERSITY OF CHICAGO PRESS 



CHICAGO ILLINOIS 



