1848.] MURCHISON ON THE STRUCTURE OF THE ALPS. 207 



tion of the chalk of North Europe and of the scagha of North Italy, 

 is of very considerable thickness, certainly several hundred feet. 



The largest superficies in which the inoceramus limestone is ex- 

 posed, is around the dome-shaped masses, the external faces of which 

 dip rapidly dowT^i into the great ravines north-east and east of Burg- 

 berg. In the latter we perceived it to be overspread by a thin course 

 of dark greyish, fatty marl, in which we detected one inoceramus. 

 This band is immediately surmounted by marly and incoherent, 

 slightly micaceous, thin-bedded sandy shale, which here has been 

 largely denuded, and above Burgberg is exposed in a transverse de- 

 pression between the Griinten mountain on the one hand and the 

 lower nummulitic ridges on the other. 



This hollow space (the Yust) between the external face of every 

 stratum to which the terms * chalk' or * cretaceous' can rigorously 

 be applied, and the lowest band of nummulitic limestone, is occupied 

 in its lower portion by the small micaceous shale and schist before 

 mentioned, which is succeeded by a greenish sandstone associated 

 with impure greyish limestone and dark grey shale. These beds, 

 particularly the sandy impure limestone, contain the same Gryphcea 

 vesicularis which has been remarked as lying between the inoceramus 

 limestone and the nummulitic rocks of the Fahnern in Appenzell. 

 Here, however, this intermediate band of green sandstone, schist 

 and limestone {e of the diagram) is vastly more expanded. If the 

 section be made in the regular ascending order of the mountain 

 (fig, 17), as followed from its main escarpment, over its summits, 

 down the Gundalpe, and across the Vust to the nummulitic ridges 

 east of Burgberg, this intermediate group (e) is seen to be perfectly 

 conformable to the inoceramus limestone beneath it, and to the lowest 

 nummulitic rock above it. Equally is it conformable if another 

 section at right angles to the above be made from the Griinten to 

 the valley of the Starzlach, a little to the south of the chief mines, 

 and where a rivulet descends from the mountain (see fig. 18). In 



Fig. 18. 



The Griinten. 



Cretaceous. Nummulites. Flysch. 



Starzlach. 



-;p S.E. 



V 



N 



babcdefff g 



this section the beds are more nearly vertical, and necessarily occupy 

 very small horizontal spaces. The same order being followed from 

 centre to flank, i. e. from the neocomian through the greensand 

 and cretaceous strata, the explorer does not fail to observe a great 

 thickness of bluish grey, slightly micaceous marls, and marlstone 

 associated with a sort of greensand, and beds of impure grey lime- 

 stone with white veins (e), in which we again detected the same Gry- 

 pheea as in similar strata in a like position in the other section near 

 Burgberg, p. 205. 



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