70 



MARION EXPEDITION TO DAVIS STRAIT AND BAFFIN BAY 



Glaciation in Greenland 



Greenland, sixtli lar<i:est of continents. (lischar<2:es every year some- 

 thin*;: like ir).000 sizable iceber^js. The continent, with the American 



Arctic Archipelago, is so 

 placed that it nearly blocks 

 off polar commnnication on 

 the west, but w^ith Spitz- 

 ber^ren to the east it forms 

 a connection between the 

 Atlantic and the polar 

 basins. 245 miles in width. 



The (reneral j^hysiography 

 of Greenland and of its ice 

 sheet, the ]K)ints of iceberg 

 dischar<re. and the approxi- 

 mate number of bergs pro- 

 duced in time and place are 

 discussed in the following 

 pages but other subjects not 

 so closely related to ice- 

 bergs, such as the origin of 

 the inland ice. its tempera- 

 ture, structure, snow limits, 

 mechanics of motion, etc.. 

 are omitted as leading too 

 far afield. 



Our }u'esent knowledge of 

 the inland ice comes from 

 the records of various short 

 excursions toward the in- 

 terior, and also from nearly 

 a dozen complete crossings 

 between the east and west 

 coasts. If we exclude the 

 northern unglaciated sec- 

 tion, composed of sedimen- 

 tary layers, practically all 

 of ' the plateau on which 

 the inland ice lies is of 

 gneiss, sloping gently to- 

 ward the northwest. Basalt 

 outpourings of the Tertiary 

 l)eriod are visible around 

 the unglaciated fringe on 

 the western side at Disko 

 Hay and on the east coast 

 in the vicinity of Scoresby 

 Sound and Jameson Land. 

 Koch (1028. 1). 488) con- 

 structed h)ngitudinal eleya- 

 ti(ms of the continent, using 

 as ordinate values the heights of the land along each coast. These 

 profiU's plaiidy show the general sliai)e of tlie hind border as it slopes 

 tVom the soutli toward tiie north, but prol)al)ly the most imi)ortant 

 physiographical point revealed on them is the V-shai)ed cut midway 



5 



The Topography of the Greenland Ice 

 AND A Transverse Section 



Fkuue o(i. — Thf ice cap is composed of two 

 and possibly tlirci^ domes. aU of wliicli obtain 

 the fii-catest altitnde In the south, with inoiv 

 ;;ra<lually decending slopes facing the nortli. 

 ( I'Mgurc after de Qnervain and Mercantoii. 



