Reviews. 



Elements of Geology, a Text-Book for Colleges a?td for the General 

 Reader. By Joseph Le Conte. Fourth edition, revised and 

 enlarged, with new plates and illustrations. D. Appleton 

 and Company. 1896. 



The many excellences of this admirable text-book are too well 

 known and too highly appreciated to need recital in detail. The 

 author has endeavored to select those phases of geology which are 

 most interesting to students and to general readers, and in this he has 

 attained a rare success. In the interest of a clear exposition he has 

 sought to eliminate unnecessary details, and at the same time to set 

 forth the main grounds on which conclusions are drawn. An infalli- 

 ble judgment in so difhcult a discrimination is not to be expected. 

 Few who have made the attempt have succeeded better, on the whole, 

 than has Dr. Le Conte. The style of presentation is easy, graceful 

 and lucid. A philosophical tone pervades the book, and the student 

 is never left long without a reminder of the intellectual processes by 

 which conclusions are reached, or, at least, may be reached, for the 

 reasoning, it must be remarked, savors somewhat more of the oflfice 

 than of the field, but the methods of the latter do not lend them- 

 selves equally well to easy and brief statement. 



Somewhat more than half the book is occupied with dynamical 

 and structural geology, and the rest with historical. The latter could 

 probably be wisely extended at the expense of the former, and some 

 of the dynamical and structural factors could perhaps be treated to 

 advantage in a historical form. For the average student we think the 

 history of the earth and the history of its typical features, treated 

 causally, are more valuable than an analytical exposition of agencies 

 and structures. Geology is essentially a science of the earth as an 

 organism, and the biography of that organism is its most vital aspect 

 as a factor in general education. 



The special topics which have received fresh discussion in this 

 revision of the work are earthquakes, the differentiation of rock mag- 



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