1848.] MURCHISON ON THE STRUCTURE OF THE ALPS. 241 



cation being parallel to each other and to the great axis of the chain. 

 In tracing some of these folds, we see so clearly that an upper stratum 

 has been twisted under one of greater antiquity (and which underlies 

 it at a little distance), that we thus learn a lesson on the small scale 

 which we may endeavour to apply to extensive masses ; whilst some 

 of the fractures are observed to have taken place along those portions 

 of the flexure which have least resisted. As my chief attention was 

 specially given to the cretaceous and supracretaceous rocks and their 

 relations, I seldom endeavoured to grapple with the accumulation of 

 obscurities, including metamorphism, which present themselves as 

 the observer approaches the watershed of the chain ; it having been 

 sufficient for my purpose to note how the strata in question were un- 

 coiled as they rolled over in great undulations from the centre to the 

 flank. In continuation therefore of a description of the transverse 

 section which passes from Altorf to the N.N.W. (fig. 12), I must in 

 justice say, that, as far as mere outline goes, the undulations seem to 

 conform to the wave-like progression so ably laid down by Professors 

 Henry Rogers and W. Rogers in their map and sections of the xippa- 

 lachian chain. In other words, the steeper sides of the anticlinal are 

 the most remote from the axis, whilst the longer and less inclined 

 face of each anticlinal faces the chain. This is observed first at Sys- 

 sikon, and next it is remarkably well seen near the mouth of the 

 Muotta-thal, the structure of which has been described. The num- 

 niulitic and cretaceous rocks on the south side of this valley are highly 

 inclined and almost vertical, whilst on the north side they slope at 

 the gentle angle of 20° to 25°. In the next grand curvature of these 

 masses, or towards the Rigi, a tremendous dislocation has occurred*, 

 by which, in fact, the younger jiortion of the nagelflue and molasse 

 of pliocene age is brought with an inverted dip against the escarp- 

 ment of the lower cretaceous rocks in the manner described in the 

 above diagram. Doubtless this last is a fault of many thousand feet. 

 The axis of the molasse external to the chain, runs parallel to it, as 

 before mentioned, in the environs of Lucerne. Throughout an inter- 

 mediate distance of several miles there is a development of all those 

 massive and inclmed strata of conglomerate and sandstone which 

 form the Rigi. The youngest bed, therefore, of all that vast accumu- 

 lation is thus brought into contact with, and apparently dips under, 

 lower cretaceous rocks ; and as the beds of pebble and sandstone must 

 once have overlapped the cretaceous masses, nummulite rocks and 

 flysch out of whose materials they have been formed^ the fault must 

 indeed be as enormous as the inversion is astounding. 



This grand solution of continuity between the cretaceous rocks with 

 their overlying companions, the nummulites and flysch on the one 

 hand, and the molasse and nagelflue on the other, is the most striking 

 dislocation in Switzerland. The line now mentioned trends from the 

 flanks of Mont Pilatus and passes by the south side of the Rigi, to 



* There are other minor folds, and probably dislocations, which I did not follow 

 out, in the masses of cretaceous and neocomian limestone between the Muotta- 

 thal and the Rigi. The dome-shaped arrangement of the sewer-kalk at Sewen in- 

 dicates that this must be the case (see p. 193). 



