188 ROCHESTER ACADEMY OF SCIENCE. 



erous subglacial streams issue from the ice along its margin here and 

 present conditions apparently favorable for esker formation (111, 

 80,81). 



(7) Eskers should show drift covered surfaces frequently, 

 they do not however. 



(8) Eskers trend in the direction of ice movement. There is 

 no reason why streams should flow in that direction, especially as 

 topography is often adverse. Crevasses would not be in that direc- 

 tion often (21, 111). 



(9) Why did subglacial streams follow^ rough topography and 

 parallel valleys both broad and deep? Also the presence of eskers 

 in a lateral position on the sides of valleys is inconsistent, the sub- 

 glacial waters would tend to w^ork toward the axis of the valley. 



-v (10) Deposits should be swept away as fast as formed when 

 4)aiMi iM to ice movement. 



(11) It is difficult to account for broad areas, "plains", be- 

 cause requisite arch would be too broad to support itself. Also heat 

 of water and erosion would be inadequate to form the broad chan- 

 nels except late in ice epoch when there was no movement, and then 

 the whole channel would be worn to uniform width. 



(12) It is difficult to account for knobs along the crest-line. 

 The crest should be even, uniform, sloping upward from the ter- 

 minal plain. 



(13) Branches can be accounted for only with difficulty. They 

 would be erased by glacial movement. They often make oblique 

 angles with the major ridge, they should make large angles. 



(14) Double and reticulated ridges are likewise difficult to 

 account for under this hypothesis. 



(15) As soon as the channel became partially filled with a 

 deposit there would be a strong tendency for the waters to be drawn 

 off through a side crevasse. 



(16) Eskers should be composed of coarse material and be 

 stronger and more perfectly aggraded on up slopes. 



(17) Mountain topography is apparently not favorable for the 

 development of eskers, yet it is rough leading to extensive crevassing 

 with opportunities for subglacial flow. On the other hand dissected 

 peneplain tracts are favorable (111). 



