182 Notices ofMemiors — Prof. Heim on Formation of Mountains. 



central nucleus of the mass. The granite of Puntaiglas, the por- 

 phyry of the WindgEelle, have a special interest. The various 

 schists of the central mass are repeated in the transverse section 

 making the anticlinal and synclinal folds. The central mass itself 

 contains Verrucano and Carboniferous beds — part of the Verrucano 

 being contemporaneous with the latter formation. 



The second part treats of the beds which form almost a complete 

 series from the Carboniferous to the Eocene. Fossils are in general 

 scarce enough ; they are sufficient, however, to prove the existence of 

 the Liassic, Jurassic, and Cretaceous formations. The author notices 

 among others Ammonites raricostatus found for the first time in the 

 Central Alps. 



But that which gives the principal interest to this region is the 

 gigantic foldings of the crust, of an intensity and extent the like 

 to which has not been observed elsewhere. The reversals are so 

 considerable that they surpass in extent and interest even the 

 very curious case of the Dent de Morcles, which I noticed on a 

 former occasion. 1 



The third part of the volume is occupied by a description of 

 these complicated foldings. One enormous fold, bent over towards 

 the north, borders the northern margin of the central mass ; by this 

 reversal the Jurassic, Verrucano, Porphyry, and even the Gneiss, 

 are piled up on the Nummulitic. In the direction of the Windgaslle, 

 to the lower Landalp, this fold breaks up into a large number of 

 minor ones. At the southern border of the central mass, we find 

 that the chain of the Piz Tumbif is formed by a fold which is again 

 folded — a compound fold. The middle zone, consisting of calcareous 

 sediments, which is elevated on the back of the crystalline mass, 

 penetrates, in some places, into this, forming very much compressed 

 synclinals. The Toedi itself is an enormous block of Jurassic 

 Limestone, which has been separated from the surrounding masses 

 of similar nature by prodigious denudation. At the top of the 

 Bifertenstock are seen the Nummulitic Limestones, at a height of 

 11,800 feet. Many of the most remarkable folds of this region had 

 remained unknown hitherto. 



The fourth part of vol. i. contains a description of the well-known 

 double fold which passes by the name of the Glarner Doppelfalte. 

 Escher von der Linth was the first to discover this feature, which 

 reverses absolutely the position of the beds over an extent of 454 

 square miles. Several geologists maintained that a reversal of such 

 an extent was impossible, inadmissible ! Such an opinion had for its 

 excuse an incomplete knowledge of the locality. The present work 

 is the first which gives an account of the phenomena over the whole 

 of the reversed area. The mechanical explanation which Escher had 

 broached we find here confirmed and developed in all its details. 



Apropos of this, already in the first volume are a number of 



general researches, among others, on the theory and formation of 



reversed folds. We also find there suggestions for a uniform mode of 



indicating the different parts of a fold, etc. Finally, the author 



1 Archives des Sciences physiques et naturelles, 1877, May number. [Geneva.] 



