11 



chemical action (Page 41). Similar studies of sedimentation in 

 restricted areas are also in progress in ..-lOre northern seas; the Bay 

 of Fijndy, for example, off the coast of California, and around Great 

 Britain among others. But these isolated projects must be greatly 

 multiplied, and extended out to the mud line at the edges of the con- 

 tinents, before re can hooe even to sketch in the very complex mosaic 

 picture presented by the deposition of shoal water sediments. 



Thus, judged even as a descriptive science, the sedimentary 

 geology of the sea is still in an elementary stage. Compared v/ith 

 soil science on shore, our knowledge of the muds of the ocean deeps 

 corresponds in a way to that cf some steppe or prairie region, where 

 the soil is so uniform over great areas that scattered teste will 

 give a representative picture of the whole. But we know hardly more 

 of the bottom in shoal regions tha.n exajnination of a garden plot, 

 here and there, would tell us of the agricultural possibilities of a 

 land with vfidely diversified soil. 



Knowledge of the agencies active in the complex conditions under 

 which marine sediments are now being deposited is equally elementary 

 in many respects, While in the case of an oyster bed, of a reef of 

 corals, or of a swarm of Globigerinae, the progress of the event by 

 which lime is added to the sea floor may be easily observed, great 

 quantities of limy mud are novir being laid down in tropical seas. 

 Whether bacteria are responsible for the formation of these muds, as 

 formerly supposed (Page 63), or whether they result from chemical 

 or mechanical precipitation quite independent of bacteria, as no?; 

 seems likely, is still a moot question: a question, however, of great 

 interest, not only for its bearing on events now taking place in the 

 sea, but in connection with the formation of oolitic limestones. 



The orgo.nic content of the sea bottom is discussed from the 

 biological soandpoint clsoiiThore. It also has a direct geological 

 bearing from r.an^'- angles. Perhaps rrost imiDortant here, is the 

 problem of the accumulation of the carbonaceous and bituiainous 

 substances on the sea floor, from which petroleum, natural gases, 

 and other hydro-carbons are believed to have been derived. Practical- 

 ly all geologistsl are agreed that petroleum, etc., is an end -oroduct 



1, The materials for these remarks on the oil problem in sedimentatior 

 are condensed from Doctor Davis White's report to the U.S. Navy Oon- 

 ference on Oceanography, 1936. ___^ 



of the natural distillation, under geologic processes, of organic 

 material accuKiulating in the sediments, whether in the sea, in fresh 

 water, or on land. It seems certain that in marine sediments more 

 organic material is involved than the oil of the Oopepods, Diatoms, 

 etc.; similar though the latter be to petroleum in chemical cojjposi- 

 tion. But it is still an open question ?jhether it is the vegetable 

 matter, or the animal fats that are the chief source for the geo- 

 physical and geo-chemical transformation in question. It is, there- 

 fore, important to learn to v;hat extent the soft parts of animals are 

 actually buried, and so preserved in the marine muds and oozes, and 

 how they are transformed there by bacterial action. 



