154 SCIENCE PROGRESS. 



a way that shows that the latter were then an old land 

 rid^e. 



M. Haug therefore accepts the Western Alps as 

 supplying a proof of Bertrand's law. He maintains that 

 the main structural lines were determined before the 

 Tertiary by certain lines of weakness, along which all the 

 later folds have been moulded. 



This paper is one of great interest. Its conclusions 

 in no way depend on the truth of Bertrand's law, though 

 this helps in their expression. It certainly appears to offer 

 a simpler explanation of the anomalous character of the 

 Prealpes than that of Schardt's overthrusts and overfolds. 



II.— THE GNEISSES AND SCHISTS OF THE WESTERN ALPS. 



A more important and difficult question is that of the 

 age of the beds of schists and gneisses which play so large 

 a part in the composition of the more famous Alpine peaks. 

 Upon this subject there have long been contending theories. 

 There is that of most of the Swiss Q-eoloo-ists, who contend 

 that many of the schists are altered rocks of various 

 periods, ranging from the Carboniferous to the Jurassic. 

 In opposition to this is the theory that they are all of 

 Archean age ; that there is a threefold sequence of ancient 

 gneisses, lower and coarser schists, and upper and finer 

 schists. The former is the view adopted by the Sw r iss 

 geologists, such as Heim, Schardt, Grubenmann, etc.; the 

 latter is that of most of the Italian geologists, though its 

 most active champion is Professor Bonney. 



The subject of the relations of these gneisses and 

 schists has been attacked from different sides during the 

 past year. 



The first paper to be noticed is one by Professor 

 Bonney (5), in which he reaffirms the conclusions advanced 

 in his previous paper " On the Crystalline Schists and their 

 Relation to the Mesozoic Rocks in the Lepontine Alps," 1 

 and replies to the criticisms of Heim and Stapff upon it. 



1 Quart. Journ. Geo/. Soc., vol. xlvi., pp. 187-240, 1890. 



