UPHEAVALS IN PLIOCENE TIMES. " 251 



ous country in the Tertiary period (vol. i. p. 284) ; but the 

 mountains probably were not high ; for at the time of the form- 

 ation of the Nummulitic limestone of the Flysch the sea ex- 

 tended into the middle of the region now occupied by the Alps. 

 The Flysch, formed in the sea, was already elevated at the close 

 of the Eocene period ; but it was not until the Pliocene that 

 it was thrown up to a height of 8000 feet above the sea ; and the 

 Tertiary shell-beds of the Dent du Midi occur at an elevation of 

 10,940 feet. This upheaval must consequently have been on a 

 remarkably magnificent scale. 



Contemporaneously with the upheaval of the Alps, the Jura 

 mountains were elevated. A great part of the Jura had been 

 raised above the sea-level in the Upper Cretaceous period ; and 

 a great alteration took place in Pliocene times, as in many 

 places the margin of the Jurassic system has been thrown over 

 the Miocene. The freshwater limestones of Locle, which belong 

 to the CEningian stage, demonstrate that this Jurassic upheaval 

 took place after the CEningian epoch. These limestones have 

 not only been elevated, but thrown over, and they fall towards 

 the north-west; and thus the newer formations have the ap- 

 pearance of being more deeply seated than the older ones. 

 Hence, like the last upheaval of the Alps, the final elevation of 

 the Jura belongs to the Pliocene period, and the movement of 

 the two mountain-ranges was connected. But it is not ascer- 

 tained whether a lateral pressure took place from the Alps, as 

 supposed by Studer, and more recently by Thurmann, or whether 

 the focus of the movement is to be sought in the Jura itself. 

 A lateral pressure of such power from the Alps would have 

 affected the horizontal stratification of the Miocene beds which 

 spread between the Jura and the Alps ; and their level position 

 renders this theory doubtful. Under any circumstances the up- 

 heaval of the Jura will have been influenced by the crystalline 

 rock-mass of the Black Forest * ; and therefore, as regards the 

 phenomena of elevation, the Jura near the Black Forest, and in 

 the Cantons of Basle, Argovia, and Schaffhausen, differs much 

 from the western Jura. 



* See vol. i. pp. 48 & 168. 



