AMELIORATIONS OF PRESENT ARCTIC CLIMATES 383 



the fossil faunas and floras of these and other high latitudes in cer- 

 tain periods of the Paleozoic, Mesozoic, and Cenozoic eras. The 

 present polar climates are really of the glacial order, and the present 

 epoch is, in my view, to be regarded climatically as a part of the 

 Pleistocene glacial period. The present stage seems to belong to 

 the degree of severity usually called interglacial, though we hope 

 the present stage is to prove terminal rather than really interglsicial. 



THE MORE REMOTE SOURCE OF THE AMELIORATION 



It has been indicated already that the mildness under study 

 is due to warm waters that have found their way to these localities 

 notwithstanding their location off the northwest corner of the 

 Atlantic in a region of glaciers and in spite of the polar ice-streams 

 that predominate at the surface and cross the line of connection 

 with the warm regions of the Atlantic. There is no ground to ques- 

 tion the immediate agency of relatively warm waters coming to the 

 surface in the ameKorated tracts; our problem lies wholly in the 

 localization of these emergences of warm water and the ulterior 

 causes that actuated them. In the main it is a question of the flow 

 or creep of warm rather saUne waters under colder ice-bearing 

 waters which are lighter because less saHne. Concretely, the crux 

 of our problem lies in explaining an underflow or undercreep of 

 warm Atlantic waters to the northwestern corner of the Atlantic, 

 and sending thence an offshoot 1,500 miles to the northward. StiU 

 more specific is the question why so seemingly anomalous a current 

 should be more effective at the head of Baffin Bay than is the broad 

 "Gulf Stream" or "Atlantic Drift" on Spitzbergen or on Franz 

 Joseph Land. 



Two factors in the answer have probably already suggested 

 themselves : 



I. Carrying heat under cover. — ^The very fact that the warm 

 waters of the ameKorated tracts of Baffin Bay can only, as a rule, 

 reach the place of their appearance at the surface as undercurrents 

 suggests that they lost less of the heat they gained in low latitudes 

 on the way than they would if they had flowed at the surface for 

 so great a distance. This factor of transportation under cover 

 will, I think, appear to be one of great importance in some of its 



