1910.] INLAND-ICE OF THE ARCTIC REGIONS. 121 



Dozens of these, great and small, were seen along the margin; and they 

 varied in size from tiny pools to ponds half a mile in length, and 200 to 300 

 yards in width. 



Since the water of the marginal streams is everywhere milky with sedi- 

 ment, these lakes are receiving quantities of muddy deposits, and in them tiny 

 deltas are being built. Where the lake waters bathed the ice front little 

 icebergs are coming off, in exactly the same way as in the fjord at the 

 glacier front, and these are bearing out into the lake large rock fragments 

 which are being strewn over the bottom or on the shores. Also at the base 

 of the cliffs, as well as on some of the deltas formed by rapidly flowing 

 streams, pebbles and boulders are being mixed with the clay. 



Nearly every lake shows signs of alteration in level resulting from the 

 change in outflow either to some point beneath the ice, when the lake may 

 be entirely drained, or to some lower outlet for the lake opened by a change 

 in the ice front, or by the down cutting of the stream bed where it is eating 

 its way through a morainic dam. The different elevations are plainly evident 

 from the absence of lichens on the rocks, the clay clinging to the rocky 

 shores, and the beach terraces along the old shore lines. In one case, at the 

 western end of mount Schurman, a lake of this type, with a depth of at least 

 ICO feet has recently been drained. Where these extinct lake beds exist one 

 sees revealed an expanse of muddy bottom with scattered blocks of rock. 



In Plate XXX, A and B are represented after Tarr, in the one 

 case, one of the marginal lakes, and in the other, the formation of a 

 delta under the conditions described. From the Karajak district 

 on the northern side of the Upper Nugsnak Peninsula^^^ von 

 Drygalski has described in addition to the usual rock basin lakes 

 left by the withdrawal of the ice front, a true ice-dammed lake 

 which appears upon his map as the Randsee.^"^ 



No one of the marginal lakes thus far described furnishes a 

 parallel to the interesting Pleistocene glacial lakes of the Laurentian 

 basin of X^orth America, since these developed for the most part 

 upon a surface of relatively mild relief, and the shores not formed 

 by the glacier itself were generally moraines registering an earlier 

 position during the retirement of the ice front. Perhaps an exist- 

 ing example comes nearest to being realized in connection with 

 those glaciers which descend the eastern slopes of the Andes and 

 enter the great lakes impounded behind moraines of an earlier 



"' " The Cornell tongue is situated upon the southern side of the same 

 Peninsula." 



"'' E. von Drygalski, " Gronland-Expedition," Vol. i, pp. 61-63. 



