620 CYCLES OF ORGANIC AND INORGANIC SUBSTANCES 



and mild Arctic winters has already been published. The chain of 

 reasoning goes through the deep Atlantic. The argument halfway 

 through splits into two components which are complementary. 

 The work here provides missing links for both. 



There remained a gap from well down the Reykjanes ridge to the 

 Bay of Biscay which has proved very difficult to bridge. There have 

 been dynamic objections to every tentative theory. These now 

 vanish. There seems no difficulty in accepting the spread of a 

 laminated complex of bolus-derived waters in any direction along 

 the glide planes between the several resident water masses each of 

 which is in neutral adiabatic equilibrium. 



These glide planes would also provide the channels to conduct 

 internal waves across the Atlantic from the sinking boluses along 

 the mid-Atlantic ridge which create them to the slopes of western 

 Europe where they can create turbulent mixing and ultimate en- 

 richment of the shallow waters with nutrients. 



If the thesis of this paper can be more firmly established, the 

 study begun in 1946 will have been completed. 



For the future of fisheries hydrography, if we can follow the 

 variations in thickness of the zones of conflict, i.e., obtain a measure 

 of the volume of bolus water entering the eastern North Atlantic, 

 we have an overall measure of the potential productivity of the 

 shallow seas of northwestern Europe. \'ery intensive study of a 

 few fixed stations like our station Cavall to 4000 m depth, per- 

 haps no more than one, may enable us to do this. 



Charting the Distribution of the Water Masses and Complexes 



The interpretation presented here is for a single position in the 

 Bay of Biscay. It should be possible to recognize the continuity of 

 each water mass over a wide area of the eastern North Atlantic, to 

 follow any gradual change in properties, and to seek for the source 

 where each has been created. If the general picture can be con- 

 firmed, its extension will need \ery precise and time-consuming 

 work not readily compatible with the usual pattern of deep-sea 

 expeditions. A limited aim attacked by an experimental approach 

 may more quickly and surely provide an answer. 



