212 MIOCENE PERIOD. [Ch, XV, 



sition of the Miocene and older Pliocene beds. It is, however, 

 ascertained, that the highly-inclined green sand, which comes 

 immediately in contact with the primary rocks, is the oldest 

 part of the series *. 



Molasse of Switzerland. If we cross the Alps, and pass from 

 Piedmont to Savoy, we find there, at the northern base of the 

 great chain and throughout the lower country of Switzerland, a 

 soft green sandstone, much resembling some of the beds of the 

 basin of the Bormida, above described, and associated in a similar 

 manner with marls and conglomerate. This formation is called, 

 in Switzerland, 'molasse,' said to be derived from 'mol,' 'soft, 

 because the stone is easily cut in the quarry. It is of vast 

 thickness, but shells have so rarely been found in it that they 

 do not supply sufficient data for correctly determining its age. 

 M. Studer, in his treatise on the ' molasse,' enumerates some 

 fossil shells found near Lucerne, agreeing, apparently, with the 

 testacea of the Subapennine hills. The correspondence in 

 mineral character between the green sand of Piedmont and 

 that of Switzerland can in nowise authorise us to infer identity 

 of age, but merely to conclude that both have been derived 

 from the degradation of similar ancient rocks. 



Until the place of the f molasse ' in the chronological series 

 of tertiary formations has been more rigorously determined, the 

 application of this provincial name to the tertiary groups of 

 other countries must prove a source of ambiguity, and we regret 

 that the term has been so vaguely employed by M. Boue. 



Styria, Vienna, Hungary, fyc. Of the various groups which 

 have hitherto been referred to the Miocene era, none are so 

 important in thickness and geographical extent as those which 

 are found at the eastern extremity of the Alps, in what have 

 been termed the basins of Vienna and Styria, and which spread 

 thence into the plains of Hungary. The collection of shells 

 formed by M. Constant Prevost, in the neighbourhood of 



* We trust that MM. Pareto, Passini, Sismonda, and La Marmora, will devote 

 their attention to the relative position of the several groups of tertiary strata in 

 Piedmont, by instituting a comparison between their respective organic remains, 



