188 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [DeC. 13, 



whole of the evidences as disposing him to view these rocks as 

 being of about the same age as those of the lower strata of the Paris 

 basin. He well distinguished the nummulitic and carbonaceous black 

 limestones from those of the adjacent mountains in which Ammo- 

 nites, Hamites and other secondary greensand fossils occurred, and 

 was only disposed to doubt his conclusions by the very ancient litho- 

 logical aspect of the overlying schists and limestones. Such was 

 the influence of mineral character in those days * ! Now, however, 

 that representatives of every band of the upper secondary or creta- 

 ceous rocks are known to exist in these Alps of Savoy and the Yal- 

 lais, including even the equivalent of the chalk, we see how sound 

 were the first conclusions of M. Brongniart as to the true tertiary 

 age of the black nummulitic limestones of the Diableretz. 



Intending to explore the relations of these supracretaceous strata 

 in the Swiss Alps, where the labours of the geologists Studer and 

 Escher de Linth had already succeeded in developing to a great ex- 

 tent their order, I abandoned further researches on this point in Savoy 

 and the Vallais, being satisfied with having there detected a key to 

 the order of superposition which had escaped previous observers. I 

 further presumed that the limestone with Inocerami, which I had 

 there observed to be intercalated between the greensand and the 

 nummulite rocks of Savoy, would prove to be the same as the Sewer- 

 kalk of the Swiss geologists, and future researches completely esta- 

 blished this to be the fact. 



Nummulitic Rocks and Flysch of Switzerland (" Macigno Alpin " of 

 Studer), with their relations to the subjacent cretaceous rocks. ■ 



Having touched upon the cretaceous and overlying masses of the 

 Savoy Alps, I now proceed to describe in greater detail a series of 

 sections specially illustrative of the sections I made chiefly either in 

 the company of Professor Briinner of Berne or in that of M. Escher 

 de Linth of Zurich, in the cantons of Lucerne, Underwald, Schwyz, 

 Glarus, Appenzell and St. Gallen. In so doing I shall necessarily 

 often refer to the underlying cretaceous rocks. As the general view 

 of succession has been already given, it is deemed more desirable, for 

 the better understanding of the subject, that the whole series of strata 

 in each tract which are physically connected with the nummulitic zone 

 should be collectively described, rather than first enumerate all the 

 cretaceous rocks in different districts and then revert many times to 

 the same place to describe the supracretaceous deposits. This would 

 entirely frustrate my object of showing in consecutive sections the inti- 



* *' J'hesiterais done tres peu (says M. Brongniart), malgre la position de la 

 roche calcaire qui renferme ces fossiles, malgre sa compacite, sa couleur noire, sa 

 stratification concordant avec le calcaire ancien qui est au dessous ; j'hesiterais 

 peu, dis-je, a la regarder conmie de meme formation que le calcaire grossier de 

 sediment superieur, si elle n'etait recouverte par d.^s roches qui offrent de nouveau 

 le caractere d'homogeneite et de compacite qu'on attnhue an calcaire alpin," &c. 

 (Memoire sur les Terrains de Sediment superieur, p. 44.) These overlying blackish, 

 siliceous and micaceous sublamellar impure limestones, and compact scaly lime- 

 stones with white veins, are parts of the " flysch." 



