138 MARION EXPEDITIOX TO DAVIS STRAIT AXD BAFFIX BAY 



icebergs scattered alono- this 1.200-mile train are carried past New- 

 foundland annually. Then the withdrawal of the pack from south to 

 north bares the coast and the iceberg file is severed. 



Such bergs as escape these traps are embraced in the 90-mile-wide 

 shelf waters fringing the American side of Davis Strait. Baffin Bay 

 to the Grand Bank; this zone provides an ideal straightaway sea 

 road on which the ice travels Atlanticwards. 



DlSTKIBUTIOX AND DrIFT OF ICEBERGS IX BaFFIX BaY AXD DaVIS 



Strait 



Any study of the geographical distribution of ice in the Arctic em- 

 phasizes the peculiar character of the northwestern arm of the Atlan- 

 tic that separates North America from Greenland, for Davis Strait 

 is flanked on one side, and Baffin Bay on l)oth sides, by high walls 

 of land ice making it tmique for the Northern Hemisphere. Con- 

 tinual cleavages from the ice walls discharging into Baffin Bay and 

 Davis Strait mark these regions as the most important icel)erg waters 

 of the north. 



Along its eastern shore for a distance of 500 miles Baffin Bay is 

 continually receiving a su^jply of icebergs, and no other l)ody of 

 water of this restricted size and inclosure becomes so charged with 

 land ice. The icel)erg crop which characterizes the waters of Baffin 

 Bay and Davis Strait is believed to be completely renewed there 

 every three or four years, and the fact that Baffin Bay does not be- 

 come choked and clogged shows that the movement of its water 

 masses are sufficient to effect the dispersal of the ice. The eastern and 

 northern section of the bay present the densest berg concentration and 

 the offing of the glaciers is the zone of greatest scattering. 



Our knowledge regarding the circulation of Baffin Bay Avas greatly 

 extended as a result of the Godfluuih expedition in the summer of 

 1928. The Godthaah occupied about 100 oceanographic stations dis- 

 tributed more or less uniformly throughout the bay except along its 

 southwestern side, off the coast of Bylot Island and Baffin Land, 

 where pack ice made those waters inaccessible. In the absence of the 

 text report of the scientific results of the Godthaah exi)edition we 

 have employed the station data already published in the Bulletin 

 Hydrographique (see Annually 1929, pp. :^6-4P>), to construct a dy- 

 namic topographic map in accordance with the methods described 

 by Smith (192G). The maj) has been used strictly to learn the gen- 

 eral movements of the heavy deep-drafted icebergs once they have 

 drifted away from the land and come under control of the ocean 

 currents. 



The map (fig. 91) which indicates the general direction and flow 

 of the gradient currents is especially interesting and important in 

 that it corroborates earlier assimiptions of a cyclonic circuhition for 

 Baffin Bay, i. e., a northerly flow along the Greenland side and a 

 southerly one along the American shore, the latter being the stronger 

 and the more voluminous. 



The surface topography of Baffin Bay in the summer of 1928 was 

 featured by an elongated depression occupying the major central por- 

 tion of the bay, while around the sides the sea surface in all places 

 stood the highest. This picture we have no reason to doubt, is more 



