ORIGIN OF MOUNTAINS. 807 



pressure acted unequally from the two opposite directions ; that there 

 was a shoving side and a side of greatest resistance. Further, the 

 mountain range, as a whole, has often the same inequilateral char- 

 acter, — that is, it has steep, numerous, and close-pressed folds on one 

 side, with frequently abundant metamorphic action as evidence of the 

 heat produced, and, on the opposite, a falling off into gentle swells, 

 with little or no results traceable to heat beyond some solidification. 



This front-and-rear feature, in the mountain range as a whole, and 

 also in its subordinate parts, could not have come from any force act- 

 ing from beneath the region, causing folds either side through a reflex 

 action, for the folds should then have had reversed forms on opposite 

 sides of the range. It must have been made through a side-push, 

 through a shove from one direction — that facing the steepest and 

 most numerous folds — and resistance, or a less movement, on the 

 opposite side. In the case of the Green Mountains, the position of 

 the unyielding or resisting mass behind is manifest ; for there, through 

 all the progress, stood the Archaean rocks of the Adirondacks and 

 Canada. This front-and-rear feature is common throughout the globe. 

 It is expressed in the Andes, the Sierra Nevada, the Rocky Mountains 

 as a whole, and not less in the mountain regions of the Old World. 



Professor Suess, of Vienna, speaking of the Alps, says that a glance 

 at the position of the crystalline rocks of the Finsteraarhorn overlying 

 the younger strata, shows that the folding over must have originated, 

 not in the eruption or expansion of isolated central masses, but in 

 some general horizontal movement of the mountain-system, as a 

 whole. He states that it is also apparent from the unequal- sided folds 

 in these Alps, and in the subordinate ranges of the Apennines, Car- 

 pathians, and Jura Mountains, that there was a shoving side to each 

 in the making of the mountains. He speaks of the "whole Jura 

 Mountains pressed up into many parallel bands," while, to the west, 

 " the Jurassic deposits, covering a wide area show no trace of this tre- 

 mendous horizontal movement ; " and of the "horizontal shove " from 

 one side by which the Apennines were made. 



5. General Conclusion from ascertained Facts as to the 

 Mountain-making Force. 



The preceding review of ascertained facts leads to the following 

 deduction : That the force making slaty cleavage acted laterally ; that 

 the fractures and joints in rocks are best explained, for the most part, 

 by reference to the same mode of action ; and that flexures and other 

 features of strata, and the features of mountains, indicate not only 

 that the action was lateral, but, also, that it was not equal on the op- 

 posite sides of the mountain- making region ; in a word, that the or- 



