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



ON THE INFLUENCE OF WATER AND ICE IN 



FORMING THE PHYSICAL FEATURES 



OF THE EARTH. 



BY PEOPESSOE D. T. ANSTED, M.A., P.E.S. 



It is an opinion that was once so common as to have been 

 almost universal, and that is still expressed ex cathedra, with- 

 out the slightest hesitation, by geologists of the old school, 

 that fractures, violent and sudden upheavals, and other convul- 

 sive movements of the earth's crust, have originated all the 

 marked and prominent features of the surface of our globe. 

 The reader, if he has derived his knowledge of geology from 

 some of the many popular elementary books on the science, 

 will probably believe that this doctrine is one of the most ele- 

 mentary and unquestioned in the science. He will have an 

 impression that water, although powerful as a depositing, is 

 comparatively unimportant as a formative, modifying, exca- 

 vating, and destroying agent. Such was to a great extent the 

 geological faith of a quarter of a century ago, and therefore in 

 all works in which the knowledge of the author is derived 

 second-hand from books, it is likely that such principles will 

 prevail. There is, however, a modern school of geology, in 

 which water is recognized as a first-class power in nature. 

 Whether in its fluid or solid state, water is believed to have 

 been a primum mobile in all places and under all circumstances 

 in which it can act. But most of all is the influence of water 

 now recognized as a mechanical agent, when it becomes neces- 

 sary to account for the grandest of all phenomena, the configu- 

 ration of a great mountain chain. The giant needles of granite 

 shooting upwards through the clouds, the sharp serrated 

 ridges of naked and hard rock, the deep gorges, often syste- 

 matic, and either seeming to radiate from a centre or run 

 parallel to each other for a long distance, the absence of such 

 soft stratified rock as we see forming the lower hills and the 

 plains, the general wildness and ruggedness, and the apparent 

 permanence of the phenomena, the scenery remaining unaltered 

 as we think from century to century; — all these combine to 

 suggest some great convulsion of nature as concerned in the 

 work before us, and some cause which, having effected a 

 change, ceases to act, and leaves the face of nature undisturbed. 

 And when we examine the deep chasms connected with certain 

 valleys, aud see the contortions of the rocks which apparently 

 correspond on opposite sides of these valleys ; when we recog- 

 nize details which render it certain that enormous upheaving 

 and squeezing forces have been concerned, we are yet more 



