8o6 ROLLIN D. SALISBURY 



iar. The stream was within a quarter of a mile of the edge of 

 the ice, and flowing over the upturned edges of unequally hard 

 layers of ice, which in their upturning had brought abundant debris 

 to the surface. The harder layers stood up as little ridges, ponding 

 the water above them and producing rapids below. In this 

 stream there were trivial patches of jjravel in the ponded por- 

 tions. Even here there was nothing to suggest the develop- 

 ment of an esker or a kame. There seems, therefore, to be no 

 warrant in the phenomena of North Greenland, so far as known, 

 for the belief either that there is, or can be, much superglacial 

 till, or that superglacial streams can do much in the way of 

 depositing stratified drift. 



Physical and clicmical condition of superglacial material. — The 

 statement has often been made that superglacial material is 

 highly oxidized and weathered, and that, on the basis of these 

 characteristics, it may be distinguished from subglacial material, 

 even in the drift deposits of the United States. This has been 

 repeatedly cited as a criterion for the recognition of supergla- 

 cial drift. This point was in mind during the study of the glacial 

 phenomena of Greenland, and it may be emphatically stated that 

 the superglacial drift of that land is not noticeably more oxidized 

 and weathered than the subglacial. Where superglacial drift 

 occurs, it appears to be as fresh, and its elements as firm in every 

 way. as the subglacial material to be seen but a few rods away. 



Lack of wear has been thought to be a mark of superglacial, 

 as distinct from subglacial, bowlders. But the superglacial drift 

 seen was often, though not always, as distinctly and thoroughly 

 worn as the subglacial. This never appeared to be true where 

 the superficial material arose from a nunatak, or from a hill or 

 a mountain which just failed of being a nunatak, but it was gen- 

 erally true where the material on the surface had been brought 

 up from the bottom by the upturning layers. 



Glacial drainage. — Another striking feature of the north 

 Greenland glaciers is the fact that the drainage from them does 

 not behave altogether as drainage from glaciers is commonly 

 supposed to. In the first place it is the rare exception that a 



