Rerieus — Marr's Study of Scenery. 415 



chapter ou the formation of valleys ; and the last of the chapters 

 on mountains deal very fully and clearly with the origin of certain 

 forms. The observations on p. 82 regarding the tendency of 

 vegetation to convert the typical concave denudation curve into 

 a convex curve is, we believe, here suggested for the first time, 

 and a study of photographs, depicting forest-clad valleys, appears 

 completely to bear out this theory of Mr. Marr. Admirable as 

 is the description of the development of a typical mountain range, 

 it would, we think, be still more easily followed by the reader 

 were orographical sketch-maps of the Monta Eosa and Scawfell 

 districts added in a future edition. 



In the chapters which follow on valleys, the reader is introduced 

 to the latest American nomenclature of consequent, subsequent, 

 obsequent, inconsequent, and antecedent valleys ; corrasion, com- 

 minution, peneplain, etc. Many of these terms are, no doubt, 

 useful, but it is interesting to note that the very inexpi-essive term 

 ' watershed ' is still retained, and that no Anglo-Saxon word has yet 

 been coined to denote the course of a river represented by the 

 German word 'Thalweg.' 



Chapters xi and xii, which deal with lakes, are perhaps the most 

 interesting in the book, our author himself having written largely 

 on the subject, and being our greatest authority on our own lake 

 district. In this connection we are glad to see Mr. Marr referring 

 to the work of that excellent old author Jonathan Otley. 



The chapters on Plains and Deserts are also very fully treated 

 of, and a long way ahead of the chapters on these subjects usually 

 found in textbooks ; in fact, it is wonderful how much up-to-date 

 information the author has compressed into his little book. 



The chapters devoted to Ice are perhaps a little curtailed compared 

 with other portions of the subject, and we would call attention to 

 the scant notice given to the work of avalanches, although it has 

 been estimated by Inspector Coaz that one-third of the snow which 

 annually falls on the St. Gothard range is removed by avalanches. 

 We should like also to see a reference to Heim's work on 

 ' Gletscherkunde ' and the observations of the Ehone Glacier 

 Commission. Upon the vexed question of the coincidence of lake 

 basins and ancient glaciers, we are glad to see Mr. Marr reminding 

 his readers of a fact long ago pointed out by Sir Charles Lyell, viz., 

 that in a region undergoing elevation glaciation will often prevent 

 the water-ways from being kept open by rivers during the uplift; 

 and in this way lakes may be formed. Such lakes, then, will be 

 caused, not by the erosion of ice, but by the absence of erosion 

 by water, owing to the presence of the ice. 



The book has been designed to interest the general reader as well 

 as to assist the student, and the changes of styles in neighbouring- 

 paragraphs are in consequence perhaps occasionally rather abrupt. 



On the whole, if we might offer a suggestion on what is evidently 

 a very conscientiously written work, it would be in favour of 

 a somewhat less technical treatment, with, however, full references 

 to works where the details of the subject may bo consulted, bearing 



