REVIEWS 651 



The accompanying text presents briefly and eflfectively fundamental facts 

 concerning the various minerals, under headings such as uses, geologic 

 occurrence, geographic distribution, technology, centers of consumption, 

 and the like. 



The atlas is an outgrowth of investigations of mineral problems begun 

 during the war, investigations of a type too long delayed in this country, 

 for the facts concerning the distribution, quahty and quantity, availa- 

 bility, and commercial and political control of the world's mineral 

 resources are destined to affect increasingly our trade and industries 

 and our relations with other peoples. 



Harlan H. Barrows 



An Introduction to Paleontology. By A. Morley Davies. Lon- 

 don: Thos. Murby & Co.; New York: D. Van Nostrand & Co. 



Mr. Davies has planned his book with the intention of making it, 

 above all else, a practical, usable textbook for courses in the elements of 

 paleontology. To this end, he begins with those animals which are most 

 common as fossils, and which can be studied most easily by the beginner — • 

 the Brachiopoda. He first describes certain common species, in order 

 to give the student a clear idea of the general characters of the group, 

 and then presents a brief, but tolerably adequate, account of the entire 

 class. 



From the Brachiopoda the author carries his text along the ascending 

 scale, through the vertebrates. He then returns, begins with the 

 Echinodermata, and follows the descending order, finishing with the 

 Protozoa. The system of treatment violates tradition, and certainly 

 has the disadvantage of leaving a beginning student in something of a 

 muddle as regards classification. But it has the advantage of beginning 

 with the easy, and proceeding to the difficult, and parallels the system 

 of treatment used in several of the more recent and progressive high- 

 school texts in zoology. 



On the other hand, Mr. Davies has adopted a few innovations that 



are neither advantageous nor, so far as can be seen, justifiable. There 



is no clear ground for separating the Molluscoidea into two groups, and 



putting the Bryozoa with the corals; neither is it plain why the Pythono- 



morpha have been omitted entirely, and the Aves reduced to an order 



among the Reptilia. These are points that an instructor may correct, 



but it is not clear why he should be forced to do so, 



C. L. F. 



