and of the Alps of Savoy. 107 



rassic, we must add the cretaceous and nummulitic forma- 

 tions, as well as 1300 metres of macigno. 



The macigno rocks being somewhat friable, a part must 

 have fallen down at the time of projection ; but it is probable 

 that at some points they have continued unimpaired, and that 

 it is only by degrees, by the effects of denudation and falling 

 down, that certain aiguilles have been lowered to the still 

 considerable height which they now occupy.* 



* This elevated summit is situate at the end of the valley of the Reposoir, 

 and has never been measured. See Saussurc, Voyages, § 285 and 1977. 



JTOTE. — Glance at the Geology of Switzerland, Extract of a Discourse pronounced 

 at the Jubilee of the Society of Natural Uistory of Zurich, on the 30th November 

 1S46, by jr. Arnold Escher de la Linth. — M. Escher, after referring to the works 

 of some Swiss Naturalists, such as Scheuchzer, Saussure, Ebel, Oharpentier, 

 Studer, &c., explains the geological phenomena of the Alps. He first adverts 

 to the distribution of the two great masses of mountains, as pointed out by M. 

 Studer; then the fan-like structure of the central chains, the metamorphism, 

 age, and dislocation of the deposits of the Alps, the geographical limits of the 

 formations, their relative position, and the conclusions which may be drawn 

 from the geological history of this country. According to the author, there does 

 not exist in it any formation more ancient than the lias ; on it all the forma- 

 tions even to the upper chalk, rest with a conformable stratification. No dis- 

 location, therefore, took place during the whole time these immense deposits 

 V. ere forming ; but there was a convulsion between the deposition of the flysch 

 (at the end of the cretaceous period), and the molasse. It is impossible to ex- 

 plain otherwise the absence of molasse among the Alps. It was at this period 

 that the metamorphic action was exerted, and that many of the sedimentary 

 rocks became crystalline. But after the molasse period, during which the Rhi- 

 noceros, Mastodon, Stag, &c., lived, another revolution took place, the principal 

 effects of which were the formation of the basins of lakes, and the opening of 

 the transverse valleys of the Reuss, Linth, &c., valleys which commence in the 

 centre of the chain of the Alps, and are continued in those districts where the 

 ground is formed by molasse. It is at a later period that the erratic formation 

 was spread abroad, the transportation of which M. Escher ascribes to the gla- 

 ciers. — {Bih. Univ. de Geneve, May 1847, p. 418.) 



