MICHIGAN ACADEMY OF SCIENCE. 21 



the lake from the cliffs and melting glacier that the lake in places 

 is being filled quite rapidly. Small lateral moraines, thirty or 

 forty feet high, are at present being deposited at the sides of the 

 glacier; the terminal deposits are below the level of the lake, con- 

 siderable debris being carried far out into lake on the ice cakes 

 before they melt. 



On the east shore of Iceberg Lake opposite the glacier, there is a 

 very fine example of a "wall" or ice rampart built by ice action. The 

 l>each, as shown by Plate IIA is here composed of rocks of all shapes 

 and sizes; it is several feet in height and in many places over thirty 

 in width. This ice rampart was chiefly formed by the stones com- 

 posing it being frozen in the ice and slowly pushed up on the shore 

 by its movement. Great changes of temperature would be one cause 

 of this movement by causing the ice to first contract by cooling, 

 often opening cracks into which water would penetrate and freeze 

 thus again covering the lake's surface with a solid sheet of ice; then 

 when the temperature increased the ice Avould expand and pusli 

 any rocks frozen to it a little way toward and then upon the beach. 

 The stones thus slowly accumulating would form the ice rampart or 

 ''wall." The motion of the glacier may also have been imparted to 

 the ice floes and have caused much of this ice push. 



Prof. M. J. Elrod, later in the summer of 1914, found two species 

 of living organisms in the cold Avater of Iceberg Lake, a mayfly 

 larva and a red entomastracon. As the temperature of the water is 

 thirty-six degrees Fahrenheit it is remarkable to find any animals 

 living under such conditions. 



The walls of the cirque aboiit Iceberg Lake appear to be \m- 

 scahible, yet mountain goats are usually to be seen walking mi- 

 concernedly along the narroAv ledges in search of the scanty grass 

 which rapidl}^ springs up as the snow melts away. In spite of the 

 renu>teness of this region and the long winters and short summers, 

 the prospector searched here for minerals years ago and the visitor 

 can see two of his abandoned prospect tunnels on opposite sides of 

 the hike. All these things add to the interest of a trip to Iceberg 

 Lake, but naturally after all the chief interest is in seeing icebergs 

 and floes floating m a lake in midsummer, and remembering 11i.it 

 this is the onlv occurence of the kind in the United States. 



