236 PRINCIPLES OF STRATIGRAPHY 



stream to be carried northeastward, far out into the Atlantic. Of 

 the two great current rings thus formed in the Atlantic, that of the 

 North Atlantic turns clockwise, that of the South Atlantic counter 

 clockwise. The areas enclosed by them are relatively free from 

 currents, both air and water, and mark a region of high air pressure. 

 The northern is filled with the floating seaweed forming the Sar- 

 gasso Sea, while the southern is relatively free from accumulated 

 drift material. Transportation of floating material (plankton) 

 from one circle to the other occurs sometimes, but generally these 

 circles remain distinct. 



The Arctic Ocean. In this ocean the chief current is the 

 continuation of the Gulf or Atlantic stream, which, after giving 

 ofif a branch to the southeast into the North Sea around the North 

 British coast, continues past the Shetland Islands along the Nor- 

 wegian coast to beyond North Cape, where it splits into a number 

 of minor streams, one of which, the North Cape current, turns east 

 along the north coast into the Parent Sea, to the south coast of 

 Nova Zembla, with a branch north to Franz Josef Land. Another 

 arm continues northward to Spitzbergen, where it can be recognized 

 beyond 80° north latitude. All along its course, driftwood from 

 tropical regions has been observed, the most noted example being 

 the bean of the West Indian Entada gigalobium, one of the com- 

 monest drift materials of the Gulf Stream, which was found by 

 Otto Torell in latitude 80° 8' north, longitude 17° 40' east, the 

 western point of North East Land. The cold currents most pro- 

 nounced are the East Greenland current already noted and its 

 branch, the East Iceland current. This meeting with the warm 

 water of the Gulf Stream extension produces a series of compli- 

 cated whirls, which have a decided influence on the distribution 

 of the temperature, the salinity, and, with these, the planktonic life. 

 (See the maps given by Helland Hansen and F. Nansen-30; 

 Krummel-42 : 6j2.) Various other cold streams have been charted, 

 such as the cold Bear Island stream, issuing from the Barent 

 Straits, another issuing from Kara Straits and passing along the 

 south and west coast of Nova Zembla, one between Nova Zembla 

 and Franz Josef Land, and one between the latter and Spitzber- 

 gen, flowing southward and westward. All these are branches of a 

 general southward drift of the cold surface waters of relatively low 

 salinity, which result from the inpouring and excessive precipitation 

 of fresh waters, and give the arctic waters in general a higher level 

 than that of the neighboring oceans. On the Atlantic side the out- 

 lets are on the two sides of Spitzbergen, especially between Spitz- 

 bergen and Greenland. Another line of outflow is from the waters 



