275 



the gliding to take place upon a layer of frozen ground near 

 the surface M. 



On the nature of the sea-bottom oflf East Greenland and on 

 the former extension of the ice. One of the most interesting 

 questions to be solved inside the polar circle is to know what 

 particular forces are active here in forming the marine sedi- 

 ments and to what extent, moreover, under different circum- 

 stances they differ in the polar regions from those of other 

 regions. In his description of the samples of the sea-floor of 

 our expedition, 0. B. Bøggild has given us some extremely 

 valuable contributions to these enquiries^). The author shows 

 us how the Coarse material in the sea-floor sediment near the 

 shore shows an intimate dependence upon the rocks cropping 

 out in the neighbourhood, which is not the case to the same 

 extent further out to sea. I can only confirm this. When, in 

 dredgings, considerable masses of loose material were often 

 brought up, I examined hundreds of stones and pebbles, though 

 without being able to make exact determinations or calculations. 

 But the general impression is precisely the same as that arrived 

 at by Bøggild after examining smaller but much more numerous 

 samples. Near land at the basalt coast to the S. of Scoresby 

 Sund, the stones consisted almost exclusively of basalt; in the 

 sea off Sabine I. was found a rich alternation of rocks, among 

 which grey gneiss was predominant. 



It is unnecessary to refer in detail to the contents of 

 Bøggild' s work, and though I should like to touch upon 

 several points, I must content myself with the following general 

 remarks. On the whole the matter is perhaps more complicated 

 than Bøggild supposes. There is no doubt that a large 

 number of icebergs even now drift out from the inner arms of 



M A short account of some of the phenomena connected with this appears 

 in my article, "Über die Natur der Polarländer"; Geogr. Zeitschr., 1907, 

 p. 563. 



*) Medd. cm Grenland, XXVIII, 17, 



18* 



