1848.J MURCHISON ON THE STRUCTURE OF THE ALPS. 2^3 



group where most extended is divided, as before said, into no less 

 than six or seven parallel ridges, with intervening troughs ; and all 

 this in a ver}'^ short horizontal distance, wherein nearly all the strata 

 from the lowest neocomian to the flysch above the nummulites are 

 repeated over and over. Now, if these plications with vertical and 

 inclined axes be due to any force which has proceeded from the 

 centre of the Alps, is it not extraordinary that this group of the 

 Holier Sentis, so far from that centre, should exhibit this extraor- 

 dinary amount of contortion, and should also in this respect differ so 

 essentially from other parts of the zone of which it is a prolongation ? 

 for in following the same band of the calcareous mountains to the 

 south-west, through Switzerland, it is found to be of much simpler 

 contour ; presenting seldom, if ever, more than one or two folds and 

 a fault '^ 



General View of Changes in the Alps. 



Whilst the inaccessible forms of large portions of the Alps, their 

 fractures and curvatures, and the enormous piles of rubbish on their 

 slopes, render it difficult to trace accurate sections of them, the general 

 survey of this chain warns us not to infer the independence of for- 

 mations from the unconformable or broken relations of any one tract. 

 Having full confidence in the accuracy of the observations of M. 

 Favre in the region so much examined by De Saussure, — observa- 

 tions the more to be admired as they have been carried out in 

 the very spirit of his illustrious precursor, — let us admit with him 

 that the terrain a numnndite near Geneva f and in parts of Savoy 

 reposes on Jurassic rocks, or neocomian limestone or greensand, just 

 as it has been observed in the Maritime Alps by Sismonda, and near 

 Chambery by Chamousset. Still, this is only a proof, that in such 

 localities the mtermediate cretaceous beds have either not been ela- 

 borated, or have been denuded by local causes before the deposition 

 of the nummulite rocks commenced. Such examples of a want of 

 regular sequence cannot be maintained, as M. Favre contends, to be 

 proofs of independence, when set against the examples of superposi- 

 tion and passage into the chalk at Thones in Savoy, in the Appenzell 

 Alps, and in the various parts of Switzerland and Bavaria above cited. 

 The latter must be ^-iewed as the rules of order and succession. 

 Again, judging from the local sections near Samoens and Taninge in 



* Professors Studer and Bnmner have written to me on the application of the 

 theory of Professor Rogers to the Alps. Though both of them seem to have had 

 in a certain sense a perception of his views, still his explanations of faults appear 

 to me to be distinct from those of any of his precursors or contemporaries. The 

 sections of M. Dumont of the palaeozoic strata of the Ardennes and the palaeozoic 

 strata around Liege make perhaps the nearest approach to them. Professor Studer 

 had shown, that the undulationsof the Jura, as described byThurman, resulted from 

 the elevation of the Alps (Bull. Soc. Geol. Fr. vol. ix. and Geogi-aphie Physique, 

 t. xi. p. 235). But Professor H. Rogers is quite of a different opinion respecting 

 the undulations of the Jura. Judging from their form, i.e. with the long slopes 

 towards the French side, and their steep slopes towards the Alps, he infers, on the 

 contrary, that the propelling force came from the Black Forest. 



t Bulletin de la Soc. Geol. Fr. 2nd ser. vol.iv. pp. 999-1001. 

 VOL. V. PART I. T 



