230 THE JOURNAL OF GEOLOGY. 



ice are of all sizes up to twenty or thirty feet in diameter, but 

 those of large dimensions are not common. The stones are 

 rough and angular except when composed of material like gran- 

 ite, which on weathering forms oval and rounded boulders of 

 disintegration. So far as has been observed, very few of the 

 stones on the glacier have polished or striated surfaces. The 

 material of which the moraines are composed is of many kinds, 

 but individual ridges frequently consist of fragments of the same 

 variety of rock, the special kind in each case depending on the 

 source of the thread in the great ice current which brought the 

 fragments from the mountains. 



In many instances, particularly near the outer border of the 

 ice sheet, there are large quantities of tenacious clay, filled with 

 angular stones, which is so soft, especially during heavy rains, 

 that one may sink waist deep in the treacherous mass. Some- 

 times blocks of stone a foot or more square float on the liquid 

 mud and lure the unwary traveler to disaster. 



On the eastern margin of the ice sheet adjacent to Yakutat 

 ba}^ where the frontal slope is low, there are broad deposits of 

 sand and well rounded gravel which has been spread out over 

 the ice. On the extreme margin of the glacier this deposit 

 merges with hillocks and irregular knolls of the same kind of 

 material, some of which rise a hundred feet above the nearest 

 exposure of ice and are clothed with dense forests. The debris 

 is so abundant and the ice ends in such a low slope that it is 

 frequently impossible to determine where the glacier actually 

 terminates. The water-worn material here referred to as resting 

 on the glacier, has been brought out of tunnels in the ice, as 

 will be noticed further on. 



Surface of the fringing ntoraiiies. — A peculiar and interesting 

 feature of the moraine on the stagnant border of Malaspina gla- 

 cier is furnished by the lakelets that occur everywhere upon it. 

 These are found in great numbers both in the forest-covered 

 moraine and in the outer border of the barren moraine. They 

 are usually rudely circular, and have steep walls of dirty ice which 

 slope toward the water at high angles, but are undercut at the 



