40 



A^A TURE 



[November 9, 189; 



f ict that the lower portions of large glaciers do move over level 

 or nearly level ground, and that for considerable distances. 

 Whether the bottom layers of the glacier move at all under such 

 circumstances does not matter much, but that the surface layers 

 move is proved by the manner in which stones are carried down 

 nnd deposited in a moraine often several miles distant from the 

 foot of the steep slopes at the head of the valley. I am inclined 

 to think that the amount of plasticity attributed to ice, founded 

 on laboratory experiments, has been considerably underrated, 

 and that under the conditions in which it exists in a large 

 glaci'^r it does actually flow, though very slowly, like a viscous 

 boiy. Why gravity shAuld cease to do any work on the ice. 

 when it rests on a level surface, as Sir H. Ho worth states, I 

 cannot see, and when we consider the enormous thickness and 

 weight of ics in a large glacier, there seems nothing strange in 

 its spreading out or flowing In the only direction in which motion 



posits, the stream which rushes out from beneath the glacier is 

 unable to cut down into the solid rock. Therefore, supposing 

 the erd of the glacier to remain at or about the same position 

 for a long period, and allowing for a moment that there is any 

 erosion whatever going on beneath the glacier higher up, there 

 is undoubtedly a tendency towards the formation of a hollow, 

 closed at its lower end by a rock barrier. 



Having clambered over the masses of moraine matter which 

 conceal the lower end of the glacier, we enter upon a broad 

 expanse of ice comparatively free from boulders. Here the 

 surface of the ice usually lies at a very gentle inclination, and 

 may continue in this manner for several miles, until the foot of 

 the steep snow-covered slopes, riddled with crevasses, forming 

 the third stage alluded to above, is reached. It is to this 

 middle, gently sloping portion of the glacier that I wish 

 especially to draw attention, as it is here that the agent of 



Glacier at head of Bhutra Va'.ley Zanskar Rang , Kashmir, a Old INIora'ne ; /■, present termination cf glacier. 



is possible, if we allow any degree of plasticity whatever. In 

 the second place, that erosion of some kind, and that to a large 

 amount, does go on beneath a glacier is proved by the turbid 

 state of the water which issues from the end of it, and it must 

 be remembered that this turbidity of the water is not occasional 

 like that of a river \\\ flood, but is continuous, or at least is re- 

 current every twenty-four hours, throughout a great portion of 

 the year. 



In ascending one of the larger Himalayan glaciers we notice 

 at least three well-defined stages. First, at the foot of the 

 glacier, and for a considerable distance up, perhaps a mile or 

 more, the ice is almost completely concealed by the burden of 

 moraine stuff brought down from above, which, as the ice 

 melts away, is continually being deposited on the floor of the 

 valley. As a result of the continued renewal of these loose de- 



NO. 1254, VOL. 49] 



erosion, to which I refer the digging out of the hollows, is 

 alone efl'ective. And it is in such positions — that is, imme- 

 diately below a point where the inclination of the valley de- 

 creases more or less abruptly — that in a formerly glaciated 

 region rock-basins are most commonly found. 



The ice in this portion of the glacier is traversed by occa- 

 sional narrow crevasses, into which the streams, often of con- 

 siderable size, arising from the melting of the surface ice under 

 a hot Indian sun, plunge sooner or later, carrying down 

 numerous pieces of rock with them. Even if the crevasse does 

 not originally extend to the bottom of the glacier, a shaft must 

 quickly be worn out, so that the falling water is enabled to 

 exert the whole of its force directly on the solid floor of rock. 

 These waterfalls are, of course, well known under the name of 

 " moulin," but I do not think that sufficient weight has been 



