Geology and Mineralogy. 311 



the complex crystalline rocks of New England, Professor Hobbs 

 reached the conclusion that the well-recognized methods of inter- 

 pretation of structure by folds was not applicable. His view, 

 that the region is one marked by a well-defined fracture system 

 which has determined the character of the topography and the 

 boundaries of rock formations, met with strong opposition. As 

 a method of testing his conclusions, the Calabrian district, where 

 the geology is well-known and the fault lines and distribution of 

 earthquakes have been made out, was chosen for study. A 

 detailed study of this region, concluded by careful mapping, has 

 shown a most marked concordance between the topography and 

 the fault lines on the one hand and between the fracture system 

 .and earthquakes on the other. 



The views advanced by Professor Hobbs may well seem radi- 

 cal, but the field evidence, as presented, seems so conclusive, and 

 a study of the literature has been so thorough, that, in the 

 absence of satisfactory data to the contrary, we must recognize 

 that faulting is a much more important factor in dynamical 

 geology than we have been accustomed to admit, and that earth- 

 quakes, as indicative of the location of fault lines, are worthy of 

 the most careful and systematic study on the part of geologists. 



H. E. G. 



6. Die Fossilen InseJcten unci die Phylogenie der rezenten Form- 

 en. Fin Handbuch fur Palaontologen und Zoologen/ von 

 Anton Handliesch. Lieferungen I-1V, 640 pp. and 36 double 

 plates. Price per part, 8 marks ; the book is to consist of from 8 

 to 10 parts with 50 plates. Leipzig, 1906 (W. Engelmann). — In this 

 very valuable treatise there will be brought together all that is 

 known in regard to fossil insects. The author has now been at 

 work several years in an investigation based primarily on the 

 materials in the museums of Europe and Amei'ica, and this has 

 been made possible through the support of the Royal Academy 

 of Natural History of Vienna. 



The chief object of this elaborate study is the establishment 

 of a classification of the Hexapoda based on the morphology 

 and chronology of recent and fossil forms. Among fossil insects, 

 it is seldom that more than the wings are preserved and upon 

 these the paleontologist has in the main to depend. Until 

 recently no adequate account of the venation of wings among 

 living insects, as a basis for classification, was accessible ; the 

 work of Comstock and Needham, however, has supplied this 

 great lack. Further, the application of the knowledge of recent 

 forms to fossil specimens could be made only by an entomologist 

 of general training, and paleontologists will ever be grateful to 

 Hancllirsch for the extended and successful work he is now see- 

 ing through the press. The final results of his studies will 

 appear in the concluding chapters of this book, the completion 

 of which must be awaited for another year. As will be seen 

 later, he has divided the fossil material into two categories, — 

 material that is well preserved, thus revealing the essential char- 



