24 : The Atlantic 



quite rejected. I am informed that a number of quite respectable geol- 

 ogists and geographers continue to take an interest in his theory or 

 in some modified form of his many lively ideas. 



In any event human life moves on a more limited scale and none of 

 the facts or observations of this book depend upon either the acceptance 

 or rejection of the Wegener theories, but it is almost impossible to 

 forget Wegener when we look at the form of the Atlantic either above 

 or below sea level. 



The main Atlantic is extended by three large Mediterranean seas. 

 Northward there lies the Arctic Mediterranean (which used to be 

 called the Arctic Ocean) made up of the main polar sea, which has 

 a shape somewhat resembling a half-moon, and smaller bodies of adja- 

 cent waters such as the White Sea, the Norwegian Sea, etc. There are 

 very good and simple reasons for regarding the Arctic waters as part 

 of the Atlantic and for separating them from the Pacific. Between 

 Scotland and the Faeroes, Norway and the Faeroes, the Faeroes and 

 Iceland are broad sea channels hundreds of miles in width and with a 

 depth of 1,500 feet over the sills. Through these channels the Norwe- 

 gian current and other arms and extensions of the Gulf Stream system 

 pour warm waters into the Arctic basin so that the coast of Norway 

 even to the North Cape and the south coast of Iceland are free of sea 

 ice throughout the year and even the shores of islands in the eastern 

 part of the Arctic basin are ice-free part of the year. Between Iceland 

 and Greenland, Greenland and Laborador are also broad channels 

 and through these, cold currents run out of the Arctic into the main 

 Atlantic so that there is a very free and continual exchange of waters 

 between the ocean and the sea. On the other hand the Arctic basin is 

 almost completely cut off from the Pacific. Bering Strait, which sepa- 

 rates the two, is only thirty-five miles wide and is generally shallow 

 with a maximum depth of 160 feet. 



The eastward extension of the Atlantic is, of course, the classic 

 Mediterranean, and its own extension the Black Sea. The Black Sea 

 is a specialized body of water, perhaps the most remote and inactive 

 of all the adjuncts of the ocean. There is some exchange of water 

 between the Mediterranean and the Black Sea. Through the Bospho- 

 rus, only two miles wide and 120 to 270 feet in depth, run two riv- 

 ers of water one above the other. A stream of light water with little 

 salt runs out at the rate of 12,000 cubic meters per second and a 

 stream of heavy, salty Mediterranean water runs in below it at a rate 

 of 6,000 cubic meters per second. Altogether this is very little for a 



