246 



PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [DcC. 13, 



and the molasse, the beds of flyseh are exposed vertically in the syn- 

 clinal of the valley of Oberdorf. This Dornbirn zone of nummulite 

 and flyseh rocks is therefore the third parallel trough on the right 

 bank of the Rhine, reckoning from the higher and central Alps, 

 just as the zone of the same rocks in the Fahnern, which is almost 

 lost in the fault of the Weissbad valley, is the third repetition of such 

 formations on the left bank of that river, reckoning from the copious 

 mass of it in the high mountains of Glarus, which extends from the 

 heights of Harstock across the valley of the Sernft by Elm and Engi 

 to the baths of Pfeffers and the environs of Sargans on the N.E. In 

 one portion of the outermost of these folds, or that of the *' Fahnern 

 mountain,'^ we have seen how symmetrically the nummulite rock and 

 flyseh overlie the cretaceous rocks ; whilst on the same line on the 

 north, a flank of the Hoher Sentis, a few miles distant only, the whole 

 formation is obliterated by the great fault. In the second or in- 

 tervening zone of Wildhaus, between the Sentis and the Kurfursten 

 mountains, the nummulite rocks and flyseh are regularly troughed 

 upon cretaceous rocks. In the inner parallel, however, or that nearest 

 the axis of the chain, the phsenomena of inversion "en masse" so 

 exceed in grandeur anything of which I could have formed an idea, 

 that I must direct attention to it, particularly as I had the advantage 

 of travelling over a lofty portion of the inverted tract in company 

 with M. Escher, who has the exclusive merit of having worked out 

 the data. 



Grand inversion of masses in the Canton Glarus. — Ascending the 

 valley of the Sernft by Engi to Elm, M. Escher and myself thence 

 traversed the Martin' s-loch pass, about 8000 feet above the sea; 

 and in this ridge, which separates the canton Glarus from the 

 Orisons, I saw the rocks which I now describe (fig. 28). The lowest 



N.N.W. 



Valley of the 

 Sernft. 



Fig. 28. 



Martin's-loch. 



y 



S.S.E. 



Valley 

 of the 

 Upper 

 Rhine. 



{g. Flyseh. 

 /. Nummulite rocks and Glarus slates. 

 o!. Apocrj'phal limestone. 



y. Crystalline schist. 

 0. Jura limestone. 



visible strata are schists and Glarus slates, the continuation of those 

 containing fishes, and with them sandy calcareous grits and limestones 

 with green earth and nummuhtes (/). These bands plunge directly 

 into and under the mountain, or to the S.S.E., and are overlaid by 

 a very quartzose variety of the flyseh {g) which seemed to me to be 

 a partially altered rock. On the sloping surface of these grits we 

 detected a few loose fragments of limestone with Inoceramus and 

 Belemnites which seemed to have fallen from some adjacent summit. 

 The flyseh, however, continues to be the chief rock of the mountain 



