62 MAIIION EXPEDITION TO DAVIS STl^AIT AND BAFFIX BAY 



icebergs are irregular in shape. The box-shaped berg is. therefore, 

 in generaL characteristic of the Antarctic, as the pinnacled, pictur- 

 esque type is of the north. 



We have called attention to the fact that Greenland is the only land 

 of continental size in the Northern Hemisphere which supports an 

 ice sheet. *^ At first thought it may seem surprising that other 

 extensive land areas, some of which lie much nearer the pole than 

 does this seat of glaciation. remain nevertheless quite bare. Thus the 

 northern sections both of Greenland and of Ellesmere Land are desti- 

 tute of an icy covering. Tlie white colored areas on Figure 11, 

 page 20, indicate regions of glaciation. Similarly the American 

 Arctic Archipelago is for the most part ice free, notwithstanding its 

 frigid climate. Labrador, with its low mean sunnner temperature 

 of 6.9^ C. (44.5^ F.). and its position in the summer path of low 

 pressures, might also be expected to exhibit an ice covering, but 

 actually shows only a ie^x small cirque glaciers in the Torngat 

 Mountains. High latitude, obviously, is not the only glacial require- 

 ment; there are several other fundamental climatic factors involved 

 such as precipitation, elevation, distribution of land and water, pre- 

 vailing winds, and ocean currents. Also, from a topographical stand- 

 point, a region must not be exposed to prevailing winds of a velocity 

 that the snow is blown away before it has had time to accumulate and 

 build an ice sheet. Another glacial problem awaiting solution, in the 

 case of the ice caps of Antarctica and of Greenland is. how can they 

 be continually renewed when the ice itself tends to create a cushion of 

 high atmospheric pressure, thereby tending to decrease the precipita- 

 tion and so to lessen its own source of replenishment ( Several theo- 

 ries have been advanced by Simpson. Hobbs, jNIeinardus. and others, 

 but as yet no observations or conclusive evidence has been collected. 



The snow and neve material, as they gradually accumulate, form 

 a nucleus, and increasing in mass and thickness until finally the 

 topographical features of the hinterland may be entirely obliterated, 

 wdiile the force of graA'ity causes the edges of the ice sheet to creep 

 forAvard and outAvard along the paths of least resistance. This, in 

 brief, is the history of the present 700,000 square mile Greenland 

 Dome, and also of other similar areas of glaciation on the earth. 



Greenland contains 90 per cent of the land ice of the north polar 

 regions with the remaining 10 per cent lying largely around the 

 shores of Baffin Bay. Smaller isolated areas are found on Prince 

 Patrick Island and Melville Island, in the direction of the Beaufort 

 Sea. Ice covers the Eurasian polar sector in Spitsbergen, Franz 

 Josef Land. Novaya Zemlya. Nicholas II Land, the New Siberian 

 Islands, and the DeLong group. The ice sheets of Iceland and Nor- 

 way, the only other glaciated lands Avithin the Arctic circle, are con- 

 fined to the mountain plateaus, never reaching the sea. 



Glaciation" in Arctic Eurasia 



In discussing the distributit)n of land ice, Spitsbergen deserves 

 special mention as possessing tAvo types of coA^er. Its northwestern 

 part has numerous alpine glaciers separated by ridges and peaks; 



*^ Stefansson (1922, p. 13) in remarking on the proportion of northern lands that are 

 glaciated, adds that most people visualize the far north as completely covered with gla- 

 ciers. He points out, however, that Greenland is the only land that really is extremely 

 glaciated, and the total annual snowfall of Ellesmere Land, the second largest island in 

 the polar regions, is barely one-tenth of that of St. Louis, Mo. 



