1848.] MURCHISON ON THE STRUCTURE OF THE ALPS. 199 



These Glarus slates were formerly considered, from their mineral 

 character, to be of high antiquity, and great was the surprise of most 

 geologists when in the work of Agassiz the species of fishes contained 

 in them were classed with so new a formation as the chalk. I now go 

 farther, and assert that, by geological position and association with 

 the nummulitic strata, they are certainly eocene, and possibly not of 

 older date than the lowest portion of the London clay. Nor is there 

 any evidence in the characters of the ichthyolites of Glarus to con- 

 travene this inference, but on the contrary much to sustain it. The 

 Paleeorhynchum, xlcanus, Podocys, &c., are, it is true, extinct genera, 

 but they are also peculiar and unknown in any cretaceous deposits ; 

 whilst the Fistularia, Vomer, Osmerus, and Clupsea* have not only 

 never been found in any secondary rock, but are absolutely living 

 genera. Even then, if we had no geological or stratigraphical evidence, 

 one might be fairly led, by the identifications of Agassiz alone, to 

 conclude that a formation including smelts and herrings (there being 

 three species of the latter) was of tertiary age, by the approach of 

 its fauna to the present order of things. The palseontological in- 

 ference is further sustained by these slates or flagstones containing 

 the bird Protornis Glariensis, Herman v. Meyer, and the tortoise 

 Chelonia Knorrii, Her. v. Meyer. 



In fact there need be no more difficulty in viewing these fish beds 

 of Glarus as tertiary, than the black carbonaceous hard limestones 

 and schists and flysch of the Diableretz. 



Nummulite and Flysch Rocks in the Grisons. — M. Studer has 

 shown that large portions of flysch in the Grisons have been converted 

 into a crystalline gneissose rock ; but I would now state, that whatever 

 be their irregularities of position in the interior of that canton, and 

 to whatever metamorphisms they may there have been subjected, 

 they unfold themselves with symmetry and regularity in their nor- 

 mal order between the valley of the Rhine and the baths of Pfefl'ers. 

 In the gorge of the Tamina, to the south of these baths, a clear suc- 

 cession is seen through Oxfordian, Neocomian, and upper cretaceous 

 rocks, which latter pass mider nummulite rocks ; the baths being 

 situated in vast masses of flysch interlaminated vdth nummulites, as 

 seen in a section which I made in company with M. Escher. Here 

 again many of the black flags are absolutely identical in mineral 

 characters with the so-called slates of Glarus, and although no entire 

 ichthyolites have been discovered in them, they contain the teeth 

 of fishes. 



Sections of the Cretaceous and Nummulitic Systems on the north 

 side of the Lake of Wallenstadt, and in the Hoher Sentis of Ajjpen- 

 zelL — Whilst the section of the Tamina and the baths of Pfcffers show 

 the ascending order from the cretaceous rocks up into the nummulitic 

 limestone and flysch, by far the largest and clearest exhibitions of the 

 whole succession in Switzerland are displayed on the plateaus on the 

 north bank of the lake of Wallenstadtf, and in the environs of the 



* See Agassiz, Poissons Fossiles, General Table, torn. i. p. xxxiii, where forty- 

 two species of fishes are named, 

 t When in the Tyrol with M. von Bach in the previous autumn, he assured me 



