384 T. C. CHAMBERLIN 



wider applications to be discussed later. It is not that there is 

 great importance in explaining this unique case, but the principle 

 of carrying heat under cover has far-reaching apphcations in the 

 greater climatic problems of geologic history. Even in this case, 

 as will appear a little later, much more than usual emphasis will 

 be laid on the function of the middle layer, the layer under cover, 

 in bearing warmth to the high latitudes and in promoting that par- 

 ticular phase of oceanic circulation of which the warm undercurrent 

 of Bafhn Bay is regarded as an offshoot.' 



2. Confinement rather than deployment. — ^A second factor that 

 seems to conduce to the special mildness in the areas under study 

 is the degree to which the waters of the warm currents in the Baffin 

 inlet are prevented from spreading and increasing their contact 

 surfaces and thus losing heat and suffering mixture by this increased 

 contact. Baffin Bay occupies a rather narrow, deep trough between 

 lands on either hand. It converges at its head, where the northern 

 oasis Hes, and there the warm current seems to be concentrated and 



' To forestall misunderstanding as to the extent and completeness of the overriding 

 lighter ice-bearing currents near the mouth of Baffin Bay, it is to be recognized that 

 on some charts and in some descriptions a warm surface current is represented as flow- 

 ing from the Erminger current south of Iceland around the southern point of Greenland 

 and along the east side of Davis Strait into Baffin Bay, but this is to be accepted only 

 in a qualified sense, for the connection of the East Greenland stream of polar ice-floes 

 with the Labrador current and the currents that flow down the west side of Baffin Bay 

 is not only well established but is recognized as a normal and dominant feature of the 

 general system of interchange between the polar and the Atlantic circulations. As I 

 saw this great ice-stream in July, 1894, in what I understand to be its normal state 

 for that season, its complete continuity and its dominance were very impressive, and 

 there could be no question as to the complete exclusion of any warm cross-current at 

 the surface. But the seasons bring variations in the relative strength of the currents, 

 and special winds cause diversions. Some of these special influences may open the 

 way for temporary warm currents at the surface along the west coast of Greenland. 

 Tropical wood, presumably from the West Indies or the tropical coasts of the American 

 mainland, is sometimes found on the coast of the Danish Colony, and this seems at 

 first thought necessarily to imply the continuity of a warm current from the south at 

 the surface, but the evidence is less rigorous than it seems, for floating matter may be 

 shifted from one current to an adjacent one of different type and destination by trans- 

 verse winds. Though it has seemed necessary to recognize this testimony to an 

 assigned surface current from the warm Atlantic waters into Baffin Bay, it is quite 

 certain that the mUd climates of the Danish Colony, and especially of the land of the 

 Arctic Highlanders, are not dependent on breaks in the continuity and dominance of 

 the main ice-streams that serve as outlets of the Polar Sea. 



