3Q2 PROPORTION OF MOUNTAINS TO EARTH'S BULK. 



range with that of the terrestrial globe, how small a 

 thing does it appear! It is merely, as we have said, 

 like the roughness on the rind of an orange, when 

 compared to that of the fruit itself. * A mere abrasion, 

 so to speak, rubs it off. 



And again it has been estimated by Humboldt 

 that if the whole of the mountains now existing in 

 Asia were reduced to powder and spread evenly over 

 its surface, it would not add more than 150 feet to 

 the general level of that continent, f Yet we know 

 that not only in Asia, but also generally over the 

 whole surface of the terrestrial globe, change has suc- 

 ceeded change: and deposits which incontestably were 

 created by the deposit of still water, such as the ocean 

 or some mighty lake, have been formed extending over 

 enormous areas which represent not merely 150 feet, 

 but many thousands of feet in thickness. From whence 

 did the materials to form these proceed, if not from 

 detritus carried down by the action of natural forces 

 from higher levels. 



Now in considering the probable age of existing 

 mountain ranges, the whole of those considerations 

 crop up before us afresh ; and we can have little doubt 

 that though existing mountain ranges are of vast antiquity, 

 in an historical sense, yet they are new in a geological 

 sense. This is proved by the fact of their bursting 

 through those numerous series of stratified rocks of 

 modern foundation which were (as the fossil remains 

 in them show) created by the deposits of water. For 

 this purpose it matters not whether the mountains are 



* See observations on this point in Outlines of Astronomy, by Sir 

 John Herschel. Edition of 1881, p. 23. 



j- See Advanced Text Book of Physical Geography, by David Page, 

 3rd Edition, 1883, p. 71. 



