REVIEWS 435 



the Pacific Coast. And no mention whatever is made of the volcanic 

 region of the Yellowstone National Park, a region not only character- 

 ized by great diversity of volcanic phenomena, where the influence of 

 volcanic action on the physical features of the region is most marked, 

 but one that is being constantly visited by students and tourists. 



The chapter devoted to the theories of volcanic action is good in 

 the main for an elementary treatment of the subject. But some of the 

 reasoning is obscure, especially that with reference to the behavior of 

 absorbed vapors, and the question of their presence or absence from 

 deep-seated and surface rocks. The effort to minimize the effect of 

 steam upon the eruption of lava appears to have been carried too far. 



It is greatly to be regretted that defects such as these exist in a 

 book that has so many excellent features to recommend it. 



J. P- I. 



Revised Text-Book of Geology. By James D. Dana. Edited by 

 William North Rice. American Book Company, New 

 York. 



The earlier editions of this work are so well known that interest in 

 the present edition is concerned chiefly with the nature of the revision. 

 This had been begun by Professor Dana a short time before his death, 

 but little progress had been made. By request, his former pupil, Dr. 

 William North Rice, completed the work. His aim has been to retain 

 the distinctive characteristics of the book so far as possible and, while 

 bringing it down to the present time as regards its facts, to preserve 

 the known opinions of its author. The editor has endeavored to 

 subordinate his own views to those of the original author, although on 

 certain points, as for example, geographic and climatic oscillations of 

 the Quaternary era, he would have preferred a somewhat different 

 expression. The general plan of arrangement remains unchanged 

 and the omissions about counterbalance the introductions. The 

 zoological and botanical classifications previously used were judged to 

 be obsolete and the schemes followed in a majority of the recent 

 manuals of zoology and botany were substituted. The theory of 

 evolution finds fuller recognition than in the previous editions. In 

 the treatment of metamorphism the text is considerably modified, 

 especially with reference to the dynamic phases and to the foliated 

 structure of igneous rocks. Otherwise the book presents essentially 



