156 M. Studer on the Gcologkal Structure of the Alps. 



mixed with the mass, which presents at the surface a reddish 

 tint, the result of oxidation. In the canton of Appenzell this 

 bed is seen lying under the Seeven limestone. In central and 

 eastern Switzerland traces of it have been seen in several 

 places ; but observers have not yet succeeded in following it 

 in a constant manner ; it appears distinctly only on the eastern 

 frontier of Switzerland, on the northern side of the Buet, 

 on the Col de Coux, whence it has been traced without inter- 

 ruption by Sixt, Fis, the Reposoir, &c., along the French Alps, 

 as far as the sea. The varied and numerous fossils it contains 

 have caused geologists to single it out with preference from 

 all the other members of the chalk series. 



Neocomiayi Formation. — The Alpine Neocomian forma- 

 tion, or Calcaire a Spatangus (Holaster or Toxaster) com' 

 planatus, makes its appearance under this glauconite at 

 many points in central Switzerland, and immediately under 

 the hippurite limestone, when the glauconite is awanting, 

 as, for example, in the Chain of Pilate and the Hohgant. 

 It generally has a considerable thickness. A grey lime- 

 stone, filled with nerinese and pterocerae forms it upper bed 

 in the canton of Appenzell. For the most part, however, 

 this division presents itself in the form of a thin-bedded black 

 limestone, which is marly or sandy, and which includes the 

 characteristic petrifactions of the marls of Neufchatel ; among 

 others, Holaster (Toxaster) complanatus, Exogyra Couloni, Os- 

 trea carinata, Terebratula depressay Tcrebratula biplicata, &c. 

 It does not appear that any older beds of the chalk series 

 exist either in the Alps or in the Jura. 



Tertiary Formations. — In central Switzerland the tertiary 

 deposits abut directly against the external chains formed of 

 the Alpine chalk, such as the chains of the Pilate, the Sentis, 

 and the Ralligstocke. It is not thus to the west of the lake 

 of Thoune. In the environs of Chambery, where the great 

 valley of the Swiss molasse seems to open, we see a large 

 branch of the Jura system separate itself from this last, fol- 

 low the direction of the Alps as far as the lake of Thoune, 

 and attach itself to the extreme Alpine cretaceous chain. By 

 this junction the Alpine character becomes confounded in the 

 most striking manner with the Jurassic character. The diffe- 



