﻿TJie Structure of Europe. 241 



The Upper Carboniferous and the Permian or Rothlie- 

 gende lie horizontally on the Armorican and Variscian 

 folds. 



The whole series of horsts is sharply bounded on the 

 south by a line which distinctly appears in the relief, and 

 which forms the northern edge of the third and youngest 

 mountain system of Europe, that of the Alps, the Car- 

 pathians and a series of other ranges. This system of 

 folds has been forced up from the south against the ruins 

 of the Armorican and Variscian system. The boundary 

 is as follows : in southern France the western edge of the 

 Alps, further east the northern edge of the Alps and the 

 Jura Mountains, the northern edge of our sandstone zone, 

 and then at Vienna the line bends back on itself. 



These most recent foldings we must consider more in 

 detail. 



This is called the Alpine system of folds, because the 

 Alps form its most conspicuous representatives. We see, 

 in the first place, that the Alps are much younger than 

 all the mountains already mentioned, as they embrace the 

 whole series of older stratified rocks and a large part of 

 the Tertiary formation. If the foldings of the Alps are 

 examined, it is seen that they have a much greater 

 continuity than the older foldings, because the breaking 

 down has not been so extensive ; the reliefs are here much 

 more easily seen because destroying influences have not 

 gone so far. A further phenomenon, which, for our con- 

 ception of the formation of mountains, is of great impor- 

 tance, may here also be observed — the development of 

 these Alpine folds has been hemmed in by the older 

 horsts which have resisted this action. The Alps on the 

 eastern edge of the French central plateau abut against a 

 small horst at Besan^on, on the southern boundary of the 

 Black Forest against the edge of the Bohemian horsts, 

 which in a high degree have prevented the northward 

 trend of the folds. 



