228 Reviews — Professor E. Haug^s Geology. 



III.— Teaite de Geologie. I : Les Phenomenes Geologiques. By 

 Emile Hatjg, Professor of Geology at the Faculty of Sciences in 

 the University of Paris. 8vo ; pp. 546, with 71 photographic 

 plates and 195 text-illustrations. Paris : Armand Colin, 1907. 



rilHIS is a veritable picture-book of geology, with descriptions of 

 X phenomena and features relating to atmosphere, hydrosphere, 

 lithosphere, pyrosphere, and barysphere. It embodies the latest 

 results of observation and research, which are placed before the reader 

 in a manner attractive as well as instructive, and withal characterized 

 by terse and lucid explanation and sound judgment. We are, 

 however, in this as in many other modern scientific books, brought 

 face to face with an exuberance of technical terms, the use of which 

 may be necessary as we specialize more and more, although their 

 multiplication tends to vexation. Those who read steadily through 

 this book may gather the meaning of terms as they progress, but to 

 those who take it up for reference the absence of an index is a serious 

 drawback that time will not wholly remedy. A volume such as this, 

 even if it be the first part of a general treatise, requires an index. 

 Moreover, the subject is likely to appeal to a number of readers and 

 students who might not need the second or subsequent parts. A very 

 useful feature of the work is the series of bibliographies appended to 

 each chapter, in which from about ten to more than sixty references 

 are included. 



In a brief introduction the author explains the aims and objects of 

 geological inquiry, and points out that Geodynamics, including 

 Geomorphogeny, are the topics discussed in his present volume. 

 Examples of geological phenomena are followed by explanations of 

 Lithogenesis, Orogenesis, and Glyptogenesis, the formation of rocks, 

 their upheaval, and sculpture ; subjects dealt with in detail further 

 on. The author then considers the general morphology of the earth, 

 the distribution of life on land and in water, and especially the various 

 conditions under which marine forms exist. Deutogenous or detrital 

 sediments, as well as those of organic and chemical origin, are con- 

 sidered ; and the subject leads on to that of Diagenesis, wherein the 

 transformation of sediments, the effects of dissolution, decomposition, 

 and recrystallization are dealt with. Concretions and dolomitization, 

 peat, lignite, and coal are successively discussed. 



The faeies of formations is next explained as the sum of their 

 lithological and paljeontological characters in a certain area. Where 

 the same faeies prevails the formation is Isopic, where a different but 

 still sjnichronous faeies occurs it is Heteropic. 



This subject, which is properly discussed from a natural history 

 point of view, is a fascinating one for stratigraphical geologists, who 

 have to deal not only with the occurrence of certain species forming 

 palseontological zones or horizons irrespective of sedimentary conditions, 

 but also with the occurrence of genera and species whose range is 

 limited by depth of water and character of sea-bottom. The use of 

 the term homotaxis is regarded as appropriate for strata with identical 

 palaeontological and lithological characters which occur at different 

 chronological horizons in areas apart. 



Various accumulations, such as oolite, bone-beds, and phosphates, are 



