AND TRANSPORTING AGENT PREST. 343 



form, may have been transported from the continent in a block 

 of river ice. 



As to the period of this age of transportation, it probably 

 coincided with the retirement of the continental ice-cap and the 

 elevation of Canada and the Arctic regions. Before this, the 

 glacier ice was shed directly into the ocean in front. The 

 elevation of the polar sea-bottom probably greatly strengthened 

 the otherwise weak Greenland current, thus turning the debris- 



o 



laden Labrador and Newfoundland ice to the southward. 



In connection with this, the beautifully precise theories of 

 oceanic currents do not seem to apply fully to the Labrador 

 and other northern currents, as the constant outpouring of polar 

 waters is not met by an equal inflow. Even the most northern 

 branch of the Gulf Stream is stopped at Spitzbergan, and returns 

 by way of the east coast of Greenland, apparently forced to do 

 so by the current which carried the " Fram " in a southwesterly 

 direction. The rapid rise of the north Polar regions seems to 

 contribute largely to all the currents which flow outward from 

 that point. The great depth of the Polar ocean as proved by 

 Nansen would supply the surplus water needed, through the 

 constant rise of its bottom. 



With the increasing amelioration of the climate of the north 

 temperate zone, came the gradual retirement of the Labrador 

 glaciers and the consequent cessation of the supply of the build- 

 ing material to the Newfoundland banks. Therefore, the trans- 

 portation of sea-borne detritus has been gradually lessening 

 owing to the retirement of the source of ice supply, in spite of 

 the fact that the power of the Greenland current had been 

 probably increasing until it reached its maximum a few centuries 

 ago, when the flow of ice to the southward was much larger 

 than it is now. 



The building, or increase of submarine banks, is doubtless still 

 going on, but the work in now confined to the neighbourhood of 

 Greenland and northern Labrador. 



How long this ice-bearing Arctic current will continue to 

 flow, must depend largely en the rise of the land in the polar 



