THE LAND, 293 



to that of the adjacent countries. Let us take, for example, 

 the chain of the Pyrenees, in which both the mean ele- 

 vation and the area covered have been measured with 

 great exactness, and if we suppose the whole mass of these 

 mountains to be spread equably over France, we find thai- its 

 surface would be only raised thereby 108 (115 English) 

 feet. In like manner, if the material which forms the chain 

 of the Alps were spread equably over the whole surface of 

 Europe, it would not raise it more than 20 (21.3 English) 

 feet. I have found by a laborious investigation, which from 

 its nature can only give a maximum limit, that the center 

 of gravity of the land at present above the surface of the 

 ocean is, in Europe 630, in North America 702, in Asia 

 1062, and in South America 1080 French feet (or 671, 748, 

 1132, and 1151 English feet) above the level of the sea. peo) 

 These results shew that the more northern regions are 

 comparatively of lower altitude. In Asia, the low ele- 

 vation of the extensive plains, or steppes, of Siberia, is 

 compensated by the mountain masses between the parallels 

 of 28i and 40, from the Himalaya to the Kuen-lun of 

 Northern Thibet, and to the Tian-schian or celestial moun- 

 tains. We may in some degree form an idea, from these 

 calculations, in what portions of the surface of the globe the 

 action of the subterranean plutonic forces, as exhibited in the 

 upheaval of continental masses, has been most intense. 



There is no sufficient reason why we should assume that 

 the subterranean forces may not, in ages to come, add new 

 systems of mountains to those which already exist, and of which 

 Elie de Beaumont has studied the directions and relative 

 epochs. Why should we suppose the crust of the earth to 



