and of the Alps of Savoi/. 105 



parallel with the Alps, shew that, at the period of the depo- 

 sition of the nummulitic limestone, a carboniferous formation 

 was made of great extent, which has been subjected to inun- 

 dations and immense dislocations. 



A second character of the nummulitic formation, of gi'eater 

 theoretical importance, is the following : — this formation is 

 independent, in the mode of its arrangement, of the cretaceous 

 formation which is inferior to it. This important fact merits 

 some details. 



The nummulitic beds, as I have stated, lie above the albian 

 formation, and the first zone of therudistes. But at Voii'ons, 

 near Geneva, the nummulitic rocks, under the form of gres,* 

 rest on a thin bed of Jurassic limestone, the exact age of v/hich 

 is undetermined, but which lies above a kind of limestone, 

 which is unquestionably the Oxford limestone. 



A similar disagreement has been pointed out by M. Cha- 

 niousset in the chain of Nivolet near Aix, where the nummu- 

 litic rocks rest on a coralline limestone. He states that he 

 has also observed them in the Valley of Thones, in contact 

 with a black Oxford limestone, and that M. Sismonda has seen 

 them among the maritime Alps, resting sometimes on the lower 

 chalk, sometimes on the Neocomian, sometimes on Jurassic beds, 

 which he presumes to consist of lias.'!; On the other hand, Pro- 

 fessor Studer has found the nummulitic formation, in the 

 canton of Appenzell, resting on the Seeven limestone, which, 

 as 1 have said, is superior to the albian formation ; in the 

 neighbourhood of the lalce of Thun, resting on rudistes lime- 

 stone, and at Mont-Faudon, near Gap, on the Oxford clay. 



All these instances evidently prove, therefore, the indepen- 

 dence of the nummulitic formation of the Alps. 



7. The Flgsch or Macigno, is formed by fine micaceous or 

 talcose sandstone, by coarse quartzy sandstone, by schists or 

 calcareous breccia, which always present a most remarkable 



• aiany years since, M. Boue pointed out the nummulites in these sandstones 

 at Voirons. (luide du Voyageur Gcolo;/i,jue, iii. 395. I have made the same ob- 

 scrvaMon. Tlie gies of Valerotte :it the foot of tlie Dent du Midi, near Saint- 

 Maurice in the Vulais, likewise contains nummulites. 



t Bulklin </c la Soc. Gcolug. dc France, .Second Scries, i. 02 1. 



