Influence of Water and Ice on the Earth's Features. 361 



But if this view of the influence of ice and water is true for 

 the latest geological period — if the Alps, the Himalayan moun- 

 tains, the Andes, and other mountain chains are thus mere 

 salient points of the most recent elevations, once covered with 

 great thicknesses of strata washed away during these gradual 

 elaboration of the chain, wha,t are we to say of the more an- 

 cient mountains — the results of elevation when the earth was 

 younger ? The answer is at hand. Such mountains are now 

 worn away yet further. In many places they are low ridges ; 

 in many they are absolutely pared flat. The ancient chains of 

 Europe, the Scandinavian chain, the Welsh and Scotch moun- 

 tains, and the mountains of the Salurian or Devonian periods, 

 are barely recognizable. The denudation has here completed 

 its work, and has not stopped while anything remained to carry 

 away. There are many extensive tracts where crystalline rock, 

 flat and hardly above the sea-level, was once, perhaps, the floor 

 of a mountain chain, not less lofty or less picturesque than the 

 Alps. The sea first, then the rain and air, and afterwards the 

 ice, have all in turn helped to pare away, undermine, and re- 

 move every prominence. Reduced at last from mountain 

 masses to mere shreds of hills, these also at length have given 

 way when the oscillations of level have not been sufficient to 

 shelter the remains of the inequalities before they were quite 

 destroyed. 



The modern doctrines of the action of water and ice are, after 

 all, only an extension of the views set forth long ago by the 

 fathers of modern geology. Hutton, and his interpreter, Play- 

 fair, gave similar explanations, so far as water is concerned, 

 though in their time the influence of ice was not recognized, 

 and the work done by glaciers and icebergs had hardly been 

 imao-ined. 



'n 



[Note. — It must not be supposed from some expressions in 

 this paper, that Professor Ansted intends to assert that glacial 

 ice is really (as was once supposed) a viscous body. Faraday's 

 discovery of regelation explains how the glacier flows. He 

 found that if moist ice at 32° is broken, the fragments will 

 instantly freeze together if placed in contact. Professor Tyn- 

 dall says, " Thus a wheel of ice might be caused to roll on an 

 ice surface, the contacts being incessantly ruptured with a 

 crackling noise, and others as quickly established by regela- 

 tion."— Ed.] 



