112 It. A. Daly — Limeless Ocean of Pre-Cambrian Time. 



deep-sea deposits of the present time, a considerable percent- 

 age of organic (soft-bodied) matter. This fact is all the more 

 striking since there is evidence that the bottom muds are being 

 worked over and over by scavengers through whose bodies 

 pass inorganic and organic matter together. Before the gen- 

 eral scavenging system for the sea-floor was introduced, we 

 should expect a still higher proportion of such organic matter 

 to enter into the composition of marine sediments. It is 

 therefore not a matter of surprise that sufficient organic (soft- 

 bodied) matter was entrapped within Eozoic sediment to fur- 

 nish, after subsequent distillation, the oil and gas actually seen 

 issuing from these old rocks. The greatest amount of entomb- 

 ment would be expected after the marine animals had begun 

 to cover themselves with shells and skeletons (these structures 

 retarding complete bacterial decay), and before the scavenging 

 system was well established ; it may be partly for this reason 

 that the older Paleozoic formations are relatively so rich in 

 petroleum and natural gas. Nevertheless, these fluids may 

 emanate from rocks in which there is not a trace of shell or 

 skeleton — rocks as unfossiliferous as so many pre-Cambrian 

 formations. 



Summary. 

 Premises. — The conclusions emphasized in this paper are 

 based on the following premises : 



1. The truth of the evolutionary hypothesis, especially as 

 regards the geologically late development of active hunters 

 and scavengers on the general sea-floor ; 



2. The biologically deduced fact that the evolution of the 

 main animal types, including those secreting hard parts, was 

 accomplished in the ocean ; 



3. The fact that animal types were already highly diversifled 

 in Cambrian time ; 



4. The experimentally proved fact that representatives of all 

 the main animal types can live and thrive in sea-water quite 

 deprived of calcium salts; 



5. The postulate that bacterial decomposition of animal 

 remains occurred in Eozoic time and has occurred in all subse- 

 quent time ; 



6. The experimentally proved fact that bacterial decomposi- 

 tion of animal remains causes the emanation of ammonium 

 carbonate among other products ; 



7. The experimentally proved fact that such ammonium 

 carbonate can precipitate from sea-water all of its calcium 

 salts in the form of the carbonate and some of the magnesium 

 salts as basic magnesium carbonate. (This precipitation is 

 proved to be actually progressing on the floor of the Black Sea) ; 



