118 HOBBS— CHARACTERISTICS OF THE [April 22, 



the motion of the ice is considerable the trench does not appear, but 

 the ice impinges forcibly upon the base of the nunatak. 



Englacial and Suhglacial Drainage of the Inland-ice. — In addi- 

 tion to the superglacial streams which are so much in evidence, 

 others which are englacial run beneath the surface of the ice, as 

 has often been discerned by putting the ear close to the ice surface. 

 Nordenskiold reports one instance where water spouted up from the 

 surface mixed with a good deal of air and spray. "^ Salisbury also 

 has mentioned a huge spring upon the surface of the ice in north 

 Greenland that shot up to a distance of not less than ten feet above 

 the bottom of the basin from which it issued. Owing to the fact 

 that near the margin of the ice its surface is much crevassed, com- 

 paratively little water can continue to the border in surface streams. 

 Salisbury mentions an instance where an englacial stream with a 

 diameter of about five feet issued from the vertical face which 

 formed the ice front. Most of the water flowing upon the surface 

 descended, however, to the bottom and issued largely below the 

 surface of the fluvio-glacial materials. It is, he says, a rare excep- 

 tion to find a visible stream issuing from beneath the ice at its 

 margin. In most cases, the water undoubtedly comes out in quan- 

 tities, though beneath the surface of the out wash apron, as could 

 be detected by the ear.^"^^ Peary has observed that a greater abund- 

 ance of water issues from beneath the ice-cap in extreme north- 

 eastern than in northwestern Greenland.^^- 



The Marginal Lakes. — Wherever the ice has withdrawn from 

 the rock surface and where ice drainage permits of it, small lakes 

 marginal to the inland-ice have come into existence. Special interest 

 attaches, however, to those bodies of water which are impounded 

 by the ice itself along its margin, because of the light which is 

 thrown upon the origin of somewhat similar bodies of water about 

 the great continental glaciers, of Europe and North America during 

 late Pleistocene times. Attention was called to such ice-dammed 

 lakes situated upon the margin of the Frederikshaab tongue of the 

 inland-ice by the Jensen, Kornerup and Groth expedition of 1878. 



"" A. E. Nordenskiold, " Gronland," p. 137. 



"' Salisbury, /. c, pp. 806-7. 



"■ Peary, Geogr. Jour., I. c, p. 224. 



