THE GREAT MOUNTAIN RANGES. 373 



TV /FOUNTAINS run, as we know, in detached masses 

 -k*-** through all the climatic zones, and it is also a 

 remarkable fact that what we may call the " Axis of 

 Upheaval " or elevation, is from East to West in the 

 Eastern Hemisphere, or Old World; while in the 

 Western, or New World of America, it runs from North 

 to South: showing how the great forces of Nature 

 have in these cases acted almost at right angles to 

 each other and also it is to be observed that they 

 always operate in the direction of the greatest length 

 of a continent. 



Geology teaches us that the whole surface of the earth 

 has from time to time been subjected to these changes : 

 those portions of it which are now dry land having been 

 at one time submerged beneath the bed of the ancient 

 sea; whilst many parts now overflowed by its waters 

 have undoubtedly formed part of the primeval continents. 

 It is only necessary to point to the fact of marine shells, 

 corals, sea fish, and other remains being found embedded 

 in the rocks, which are now raised high above the 

 present water level, to prove that though these rocks 

 may, in some cases, form the tops of mountains now, 

 they must at some former era of the world's existence 

 have been buried during vast periods of time beneath 

 the waiters of the sea. 



These considerations of course open up great ques- 

 tions of geological science which it would be too long 

 to discuss, and which are also foreign to the scope of 

 this work. We shall not attempt therefore to enter into 

 them except in the most general terms. Those who may 

 feel interested in such questions will find the whole subject 

 very fully discussed in the text books of the specialists 

 who have written upon it. Nevertheless there are a few 



