REVIEWS 255 



localities within the Arctic Circle, also in many other regions of both the Old 

 and the New World. These records afford an exceptionally striking illustration 

 of the possibilities offered by a study of the herbaria of the rocks of connecting 

 the present with the past, of following the wanderings over the world and of 

 tracing the rise and fall in their fortunes of still living members of the plant 

 kingdom. These fragmentary relics, "The ghostly language of the ancient 

 earth," suggest problems that are more easily stated than solved. 



Many records of ancient floras are readily decipherable, foliage shoots and 

 clearly outlined leaves showing the finest veins, the plant substance changed 

 into a thin film of coaly substance which on treatment with certain chemicals 

 reveals imder the microscope details of the surface cells and throws light both 

 on the affinities of the plants and on their relation to the world in which they 

 lived. The minute structural details of petrified wood after it has been cut 

 into transparent sections can be examined with as much thoroughness as those 

 of a living stem; the living substance has gone, but the framework remains 

 and through it we obtain an insight into the mechanism of the plant which was 

 ahve some mUlions of years ago. Other fossils are but "age-dimmed tablets 

 traced in doubtful writ," and these add zest to the task of interpretation 

 [pp. 27-29]. 



One of the most convincing and impressive arguments in support of the 

 prevalence of an almost, if not quite, tropical climate in Greenland during the 

 Cretaceous epoch is furnished by portions of large leaves and pieces of the fruit 

 of a Breadfruit tree discovered by members of a Swedish expedition in 1883 on 

 the coast of Disko Island and described by the late Professor Nathorst, who 

 was well known as an Arctic explorer and an exceptionally able student of the 

 floras of the past. The Breadfruit, Artocarpus incisa, which the Greenland 

 fossil closely resembles, is cultivated practically all over the tropics and is 

 native in some of the Pacific Islands [p. 31]. 



The little book is full of charming pictures, literary as well as photo- 

 graphic, and it is studded all through with substantial things well worth 

 knowing. 



T. C. C. 



Geomorphology of .New Zealand, Part /, Systematic. By C. A. 



Cotton. Wellington, N.Z.: Dominion Museum, 1922. 



Pp. x+462, pis. I, figs. 442. 



One of the beauties of the science of geology is the wide applicability 

 of its underlying principles. A generalization is developed in one 

 country where conditions or methods of study are particularly favorable, 

 then later it is used by geologists in far distant countries to solve problems 

 hitherto obscure. Thus its validity becomes more firmly established. 

 The chief interest to American geologists in this work by Professor 



