108 HISTORY OF THE OCEANS 



Even the early seas must have had a surface which was different 

 from their bulk. Any substances which were surface active, such 

 as hydrocarbons and their derivative acids and amines, would 

 accumulate on the surface of the primary ocean and the concen- 

 tration there may be a hundred or a thousand times as great as 

 in the bulk. Normally this very thin surface layer is not studied — 

 it escapes the nets of the plankton fishers. However, from general 

 physicochemical knowledge, one can predict how it will beha\'e. 

 The surface active materials will be concentrated in the bubbles 

 produced by the breaking waves — in the manes of white horses — 

 and most of it will end up either as mist in the air or as foam or 

 sludge on the beach. Here we have a second process of concentra- 

 tion because with an onshore wind the surface of the sea of 

 hundreds or thousands of square miles of extent can be deposited 

 along a few miles of beach. How effective such a process is appears 

 only too unpleasantly on all our tar-covered beaches on which 

 practically all the oil efifluent of ships is now concentrated. 



The surface active molecules would have appeared in the 

 earliest times as a thin layer of sludge left on the sand or mud by 

 each receding tide. It is here we might expect to find the hydro- 

 carbon molecules postulated by both Urey and Oparin. These may, 

 indeed, have entered the sea as Oparin first proposed, from fissures 

 leading deep into the earth. This new hypothesis of the superficial 

 formation and onshore drifting of the original materials from 

 which life was formed removes one of the greatest obstacles to 

 the plausibility of an inorganic origin of life in the ocean. In a 

 classical analogy, life no longer comes straight from Poseidon but, 

 like Aphrodite, it was born of the sea foam. Less poetically but 

 more accurately, it may be likened to the wind skimming the scum 

 of the oceanic cooking pot and depositing it on the beaches. 



The fate of the material deposited from the sea surface would 

 differ very much according to the kind of coast onto which it is 

 driven. Clearly a rocky coast would not lead to any fixation at 

 all, and a sand coast not very much more; where fixation would 

 certainly occur is in a mud, particularly an estuarine mud. Today 

 the composition of estuarine muds as deposited layer by layer by 

 every stand of the tide is predominantly formed from the remains 



