M. Studer on the Geological Silructurc of the Alps. 169 



the Frienisberj? near Aarberg, a third hill of a greater height 

 than 1000 feet above the level of the plain. On the other 

 hand, undulations and plateaux of some hundred feet in height, 

 and valleys of erosion of an equal depth, are the most frequent 

 phenomena as far as the Jura range. 



Molasse. — The tertiary formation of Switzerland is essen- 

 tially composed of a marly sandstone, the molasse^ whose hard- 

 ness goes on diminishing from the Alps to the Jura. Imme- 

 diately at the foot of the Alps it is an extremely compact sand- 

 stone ; in the central part of the Swiss plain, it forms an ex- 

 cellent building-stone ; and in the neighbourhood of the Jura 

 mountains the entire mass is nothing but a loose sand. Near 

 the lake of Geneva, and in the cantons of Aargau and of Zurich, 

 we find, in the lower beds of the molasse, deposits of lignite, ac- 

 companied by a bituminous calcareous marl, which often con- 

 tains a large number of fresh- water shells. The lignite itself 

 and the molasse contain teeth and bones of land-animals, which 

 are characteristic of the upper tertiary formation, and also re- 

 mains of palms. The upper part of the molasse is of marine 

 origin ; and it may be said that the entire beds consist of in- 

 ternal casts or debris of shells, more rarely of entire specimens 

 of marine shells, of which the determinable species are iden- 

 tical with those of the subapennine hills.* 



Nagelflue. — To the sandstone of the molasse we find fre- 

 quently added, in the neighbourhood of the Alps, conglomerates 

 of rounded pebbles, known under the name of nagelflue or 

 gomphoUtes. The subdivision, thickness, and even composi- 

 tion of this rock are very variable. Where the cretaceous 

 chains are in immediate contact with the molasse, as in eastern 

 and central Switzerland, the nagelflue appears in much more 

 considerable masses, and over much larger spaces than in 



* Notwithstanding this identity of fossils, authors have persisted in sepa- 

 rating the Swiss molasse from the subapennine formation, and in identifying 

 it with the formation of la Superga, Bordeaux, and Dax, whose fossils dif- 

 fer as much from those of the molasse as is possible in formations so nearly 

 approaching each other. "Whatever name may be given to those different 

 subdivisions of .the upper tertiary formation, I hope that the Swiss geolo- 

 gists who occupy themselves with the study of the paleontology of the mo- 

 lasse will continue to protest jigainst this factitious arrangement. 



