222 Scientific Intelligence. 



graphic paleontology, water resources, and economic geology of 

 the Dominican Republic. The geologic sequence begins with the 

 "basal complex" of unknown age, followed by Upper Creta- 

 ceous and Cenozoic marine formations. 



4. A Manual of Seismology ; by Charles Davison. Pp. xii, 

 256, with 100 text figures. Cambridge University Press, 1921. — 

 In writing this text book the author has purposely sought to 

 present the subject of seismolog}^ in its geological aspect. As he 

 points out, ' ' until near the close of the last century, seismology 

 was regarded as a department of geology, but while its growth in 

 that direction has by no means ceased, the more recent advances 

 have been largely the work of mathematicians and physicists." 

 But inasmuch as the present volume was written to constitute 

 one of the Cambridge Geological Series, the mathematical and 

 physical sides of the subject have in consequence been almost 

 completely omitted. 



The book gives an admirable outline of the present status of 

 the science. It deals with the phenomena of earthquakes in gen- 

 eral, and therefore it gives no detailed descriptions of individual 

 earthquakes. The presentation of the subject is well-balanced, 

 concise, and lucid, and consequently makes easy reading. The 

 more speculative matters have been eschewed and the presenta- 

 tion generally sticks to the reasonably assured ground of seismol- 

 ogy. Most of the chapters are preceded by a list of sources, 

 which can be profitably consulted by the reader who desires fuller 

 information. 



It may perhaps be suggested that the practical deductions of 

 seismologic studj^ might have been more fully treated. The 

 author's concern is essentially with the purely scientific side of 

 the subject. The practical deductions are indeed mentioned, 

 rather casually on the whole, but they would seem worthy of 

 inclusion in a separate chapter, both in view of their importance 

 and in order to make them more readily available. Probably the 

 author's attitude is unconsciously revealed by his placing in a 

 foot-note an interesting suggestion as to the probable immunity 

 of the Panama Canal cuts to earthquake damage. The facts 

 and practical deductions of seismology are of unusually wide 

 popular interest, more so probably than those of any other branch 

 of geology, and some cognizance of this interest might well be 

 taken. By providing the chapter suggested, the author would 

 aid geologists in meeting this demand. 



In conclusion, this excellent book gives us an epitome of the 

 science of seismology in its geological bearings, and by its suc- 

 cinctness and its admirable simplicity of treatment makes attrac- 

 tive much of what would otherwise be abstruse matter. It is a 

 welcome addition to the Cambridge Geological series. 



ADOLPH KNOPF. 



