250 GENERALIZATIONS. 



by older strata which have been pushed over it, so that without 

 doubt the upheaval of the chain of the Alps did not occur until 

 after the deposition of the Miocene ; and, as the Alpine upheaval 

 was completed at the time of the formation of the paper-coal or 

 lignite, it must belong to the intermediate or Pliocene period. 

 During the Pliocene, therefore, the grandest changes in the 

 orographic formation of Switzerland took place. At this time 

 the crystalline rocks, which probably formed an island even in 

 the Carboniferous period (vol. i. p. 3), were thrown up into 

 stupendous mountains by an enormous pressure acting upon 

 them from the interior of the earth. By them the stratified 

 rocks, which in the lapse of ages had surrounded them like a 

 mantle, were broken through and driven up by lateral pressure 

 into lofty saddles, or cleft into ridges, or even tilted over, and 

 their fragments, like the slabs of ice produced on the breaking- 

 up of the ice in a river, were pushed one over the other ; and in 

 this way have been produced the infinitely varied mountain- 

 forms which lend such a charm to Swiss scenery. " Just as a 

 crater with an abrupt inner precipice surrounds a central volcanic 

 focus," says Studer, in his ' Geology of Switzerland ' (vol. i. 

 p. 165), "so may one, two, or three limestone ranges lean to- 

 wards the steep rocky walls of the granite mountains, often 

 reaching up into the region of perpetual snow, and their strata 

 may dip away from the central range." The origin of the most 

 magnificent landscapes of Switzerland is therefore to be traced 

 to the crystalline rocks traversing the centre of the country and 

 forming its highest mountains. The central Alps follow gene- 

 rally a direction from west-south-west to east-north-east, by 

 no means forming a connected mass, but capable of division 

 into a number of sections, the massive rocks of which are 

 separated by stratified (Neptunian) strata. Studer distin- 

 guishes eleven such central masses, apparently due to distinct 

 foci of elevation, which, however, were probably all at the same 

 time in activity. 



The mass of which these central rocks consists belongs to the 

 primseval formation of the earth ; but it is only in comparatively 

 late times that these ancient rocks have risen into vast moun- 

 tains. No doubt the region of the Swiss Alps was a mountain- 



