48 THE ICE AGE IN NORTH AMERICA. 



point. In both instances, also, the lee side of these islands 

 seemed to be the beginning of important subglacial streams 

 of water — brooks running into them as into a funnel, and 

 causing a backward movement of ice and moraine material, 

 as where there is an eddy in water. In both these cases, 

 however, the lee sides of these islands were those having 

 greatest exposure to the sunshine. The surface of the ice 

 immediately in front was depressed from one to two hun- 

 dred feet below the general surface on the lee side. 



The ice in the eastern half of the amphitheatre is mov- 

 ing much more slowly than that in the western half. Of 

 this there are several indirect indications : First, the eastern 

 surface is much smoother than the western. There is no 

 difficulty in traversing the glacier for many miles to the east 

 and northeast. Here and there the surface is interrupted by 

 superficial streams of water occupying narrow, shallow chan- 

 nels, running for a short distance and then plunging down 

 into fissures, or, in technical language, moulins, to swell the 

 larger current, which may be heard rushing along in its im- 

 petuous course far down beneath and out of sight. The 

 ordinary light-colored bands in the ice parallel with its line 

 of motion are everywhere conspicuous, and can be followed 

 on the surface for long distances. When interrupted by cre- 

 vasses they are seen to penetrate the ice for a depth of many 

 feet, and sometimes to continue on the other side of a cre- 

 vasse in a different line, as if having suffered a lateral fault. 

 The color of the ice below the surface is an intense blue, and 

 over the eastern portion this color characterized the most 

 of the surface. Numerous holes in the ice, penetrating 

 downward from an inch or two to several feet and filled with 

 water, were encountered all over the eastern portion. Some- 

 times there was a stone or a little dirt in the bottom of these, 

 but frequently there was apparently nothing whatever in 

 them but the purest of water. In the shallower inclosures 

 on the surface, containing water and a little dirt, worms, 

 about as large around as a small knitting-needle and an inch 

 long, were abundant. 



