T>n. J. irouTsox — ice and its work. 149 



undcmcatli it over its rocky bed, is called the moraine profonde^ or 

 bottom moraine. From the foot or melting extremity of a glacier 

 a turl)id milky stream issues : the sand or mud ein])1()yed l)y the 

 ice in polishing its bed being carried out and suspended in the 

 water which flows out from underneath it. The stones employed 

 in grinding and scoring the rocks are themselves ground, smootlied, 

 and scored, and, being pushed out at the foot of the glacier, become 

 mingled with the great masses of debris brought down upon its 

 surface and discharged at its melting extremity. 



The pile of loose materials formed in this manner at the end of 

 the glacier is called the terminal moraine, and may be of very 

 considerable size. 



We can often verify by obsei'vation the fact of the smoothing 

 and scoring of the rocks over which a glacier passes. When it 

 shiinks away fi'om the side of its valley, as happens in summer 

 from the partial melting of the ice, it is often possible to get 

 below the ice and creep underneath it for some little distance, 

 when we find the rocks smoothed and polished, and showing long 

 grooves and ruts running parallel with the course followed by the 

 glacier. Every projecting mass of rock is rounded and smoothed 

 on the side which looks up the valley, while the other side retains 

 its original roughness. Smaller projections are rounded and 

 polished all over, and every dimple and hollow is smoothed and 

 dressed in a similar manner. 



As the foot of a glacier is higher up the valley in summer than 

 in winter, in the former season we can see, on the sides and floor 

 of the valley below the glacier-foot, distinct and recent evidence of 

 the action of ice, the rocks being rounded and smoothed, scored 

 and striated, as I have just described. 



Another very important thing to notice about glaciers is that 

 when a glacier diminishes in size from any cause, and shrinks away 

 from its bed, it may drop the blocks from the moraine upon its 

 surface on the sides of the valley, sometimes perched in the most 

 extraordinary manner, and looking as if the slightest push would 

 send the mover. Such stranded stones are known as perched blocks. 

 These blocks are often of a different material from the rocks aroimd 

 them, and may have been carried a long way from their origiual 

 source. 



Glaciers may be well studied in Switzerland, and on a grander 

 scale in jS^orway, where in the far north they actually reach the 

 sea-level. 



Let us now consider the condition of Greenland in the present 

 day, where we find a country almost entirely covered by a mantle 

 of perpetual ice and snow, or what in other words we may describe 

 as an enormous confluent glacier. Greenland is 750,000 square 

 miles in area, and nearly the whole of it is a frozen and lifeless 

 desert. The coasts are deeply indented by bays and fiords, which 

 when traced inland are found to terminate against glaciers. The 

 whole interior of the country appears to be buried under a great 

 depth of ice and snow, which fills up the valleys and covers over 



