July 24, 1914] 



SCIENCE 



137 



the great impetus to the study of land forms, and 

 especially of the influence of erosion on their pro- 

 duction. The concept of the peneplain, of the 

 cycle of erosion, of the sequential development of 

 rivers and erosion forms on the coastal plain and 

 on folded strata, and others chiefly due to him, 

 have become ef incalculable value to the stratig- 

 rapher. The more recent development of the idea 

 of desert planation by Passarge and Davis has 

 opened further promising flelds to the stratig- 

 rapher, who seeks to interpret the record in the 

 strata by the aid of modern results achieved by 

 universal processes. 



In the field of correlative stratigraphy the past 

 decade has likewise seen striking advances. The 

 publication of the "Lethsea" falls into this period, 

 and so does Marr's comprehensive little volume, 

 "The Principles of Stratigraphical Geology," not 

 to mention the elaborate recent texts of Haug, 

 Kayser and others, or the numerous publications of 

 government surveys, and of individual contribu- 

 tors. That questions of correlation have reached 

 an acute stage in American geology is manifested 

 by such recent publications as the "Outlines of 

 Geological History" and Ulrich's "Eevision of 

 the Paleozoic Systems," and the numerous papers 

 accompanying or called forth by these. Finally, 

 paleogeography, as a science, is of very recent de- 

 velopment, most of the works of importance hav- 

 ing appeared in the last five years. In America 

 Schuchert and Bailey Willis are the acknowledged 

 leaders, while in Europe many able minds have at- 

 tacked the problems of paleogeography from aU 



It is thus seen that this book was conceived dur- 

 ing the period of initial reconstruction of our 

 attitude toward the problems of geology, and that 

 its birth and growth to maturity fell into that 

 tumultous epoch when new idesis crowded in so 

 fast that the task of mastering them became one 

 of increasing magnitude and, finally, of almost 

 hopeless complexity. To summarize and bring to- 

 gether the ideas of the past decade, and focus 

 them upon, the point of view here essayed, is prob- 

 ably beyond the power of one individual. Never- 

 theless, the attempt to present the essentials of 

 the new geology for the benefit of those who, 

 grown up with it, have perhaps treated it with the 

 lack of consideration usually bestowed on a con- 

 temporary, as well as for those who will carry on 

 the work during the next decade or two, can not 

 but serve a useful purpose. May this attempt be 

 adjudged not unworthy of its predecessors, nor 

 unfit to stand by the side of its contemporaries. 



Having given the author's point of view, 

 there may be noted briefly the especial fea- 

 tures of some of the chapters. 



In Chapter II., on the atmosphere, in addi- 

 tion to a review of meteorological principles, 

 there is an extensive treatment of wind ero- 

 sion and transportation. Space is given also 

 to the indications and nature of rhythmic 

 climatic changes. 



The hydrosphere is treated in the next three 

 chapters. Under Morphology and Subdivi- 

 sions of the Hydrosphere are considered the 

 forms of oceans, lakes and rivers. The m.ost 

 pertinent assemblage of material of this sec- 

 tion is, however, in that chapter dealing with 

 the movements of the hydrosphere and their 

 geological effects, especially in the transpor- 

 tation and shaping of material. 



There follows in Chapter VI. a classifica- 

 tion of the rocks of the earth's crust. 



The heart of the volume is found, however, 

 in ten chapters, IX. to XVIIL, inclusive, 

 which deal with the original structures and 

 lithogenesis of the sedimentary rocks, and it 

 is for this section of 417 pages, if the reviewer 

 mistakes not, that the work will be regarded 

 as most distinctively a contribution to geologic 

 science. There is throughout an application 

 from present sedimentation to ancient sedi- 

 ments, more especially to those of the Paleo- 

 zoic. If this section be compared with those 

 dealing with the nature of sedimentary rocks 

 in the standard manuals of geology in the 

 English language, it will be seen that not only 

 is it many times more comprehensive and 

 extensive, but that traditional, over simple, 

 and conventional interpretations are retested 

 by the appeal to nature. This section leads to 

 the conclusion that a much larger part than 

 has been the custom should be ascribed in 

 earlier ages to eolian and fluviatile sedimen- 

 tation and their climatic implications. 



Chapters XIX. to XXIIL, inclusive, give 

 164 pages to metamorphism, earth sculpture, 

 igneous activity and diastrophism. Parts of 

 these chapters are better and more fully 

 treated in other works and are not clearly 

 within the province of the book, but other 



