276 



POPULAR SCIPJNCE MONTHLY. 



of the twelve districts into whicli the western coast strip is divided, some 

 account of the customs and character of the Eskimos, and a historical sketch 

 of the explorations and administration of Europeans in Greenland. His 

 descriptive matter is frequently enlivened by anecdotes, and the text is 

 illustrated by reproductions of many photographic views of persons and 

 places. 



From materials furnished by Prof. Wright and other explorers, Prof. 

 Upham has prepared descriptions of the plants and the animals of Green- 

 land and of the inland ice sheet. He also devotes a chapter to tracing the con- 

 tinental changes of level of the Pleistocene period. With this material as 

 a basis, he proceeds to discuss the causes of the ice age, giving the theories 

 that have been put forth to account for the great extension of the ice, and 

 explaining the difference of opinion among glacialists as to whether there 

 were one or more epochs of glaciation. The authors of this book hold to 

 the theory that the ice sheets were due to extensive uplifts of the land 

 forming plateaus which received snow throughout the year. In another 

 chapter the successive stages of the ice age are traced as revealed by their 

 marginal moraines and other deposits. In conclusion. Prof. Wright sum- 

 marizes the chief facts relating to Greenland's mantle of ice, and to the life 

 of its inhabitants, who seem to be admirably adapted to their surroundings 

 and happy in them. 



GENERAL NOTICES. 



Paleontology is presented from a point 

 of view somewhat different from the ordi- 

 nary in a book which Prof. Williams, of 

 Yale University, has just published.* The 

 author says that while there are no end of 

 books on evolution, and modern biologists 

 seem content to assume that some theory of 

 evolution is true, and although the sociolo- 

 gist, the moralist, and the theologian are 

 basing their theories about man on the 

 " working hypothesis " of the naturalist, as 

 if " law and gospel," it seems to have es- 

 caped serious attention that we have open 

 for study a genuine record of the actual 

 evolution of organisms, extending from near 

 the beginning of life up to the present time. 

 The geologist does not ask what is the theory 

 of evolution, but what are the facts of evo- 

 lution. The book is intended simply as an 

 introduction to an already broad field, which 

 is rapidly widening. The history of organ- 

 isms is first taken up and treated quite fully. 

 The next two chapters consist of a history of 

 the making of the geological time scale, and 

 a general consideration of its divisions. The 



* Geological Biolagy : An Introduction to the 

 Geolofrical History of Organisms. By H. Slater 

 Williams. Now York : Henry Holt & Co. Pp. 

 .392, 8vo. Price, $2.80. 



naming and the fossils of stratified rocks, the 

 nature of fossils and their geographical dis- 

 tribution next occupy attention. What is a 

 species ? What is an organism ? and What 

 is the origin of species ? are the elementary 

 but important questions answered in the next 

 three chapters. The principles of natural 

 history, classification, and the types of con- 

 struction in the animal kingdom, occupy 

 Chapters XI and XII. Phylogenesis in 

 classification, the acquirement of characters 

 of generic or higher rank, what is evolved 

 in evolution, the modification of generic 

 characters, and the plasticity and perma- 

 nency of characters in the history of organ- 

 isms, bring us to the eighteenth chapter, 

 which takes up the cephalopoda, to illustrate 

 the rate of morphological differentiation in 

 a genetic series. In Chapter XIX the am- 

 monids are studied in a similar manner to 

 illustrate the progressive modification of an 

 extrinsic character. The last two chapters 

 — one on the laws of evolution, as empha- 

 sized by a study of the geological history 

 of organisms, and finally the philosophical 

 conclusions regarding the causes determin- 

 ing the course of evolution, are in the na- 

 ture of a general smumary of the whole 

 subject. 



