60 FOUNDERS OF OCEANOGRAPHY 



settled even now, and it may well be that Darwin's theory 

 holds good in certain parts of the ocean, while Murray's 

 explanation is true for other series of atolls. 



One of the principal additions to knowledge made by the 

 " Challenger " observations was as regards the deposits now 

 accumulating at various depths on the floor of the ocean. 

 During the voyage the preservation and examination of 

 these deposits was part of Murray's work, and subsequently, 

 along with his friend the Abbe Renard, he made a most 

 comprehensive study of all the submarine deposits (about 

 12,000) that could be obtained from various expeditions, and 

 published in the " Challenger " series a most authoritative 

 report, which will be for long the standard work on the 

 subject. Omitting terrigenous deposits, which are formed 

 close to the shore and are made up chiefly of matters washed 

 down from the land or worn off from the coast, the deep-sea 

 " oozes," as they have come to be called, are divided into 

 various kinds, such as Globigerina ooze, Radiolarian ooze. 

 Diatom ooze, Pteropod ooze, according to the nature of their 

 chief constituents, while another most extensive deposit, 

 occupying over 50 miUion square miles on the floor of the 

 ocean at depths of over 2,000 fathoms, contains compara- 

 tively few conspicuous organisms and is known as Red 

 Clay because of the alumina and iron and manganese which 

 it contains. In some places associated with the Red Clay 

 are found great deposits of manganese nodules, ear-bones of 

 whales, and gigantic sharks' teeth apparently belonging to 

 extinct species. It was the " Challenger " observations that 

 first enabled oceanographers to map out the distribution of 

 these pelagic oozes on the floor of the ocean, and which first 

 gave us a rational explanation of their nature and process 

 of formation. 



In connection with deep-sea deposits, it may be appro- 

 priate to point out that it was the naturalists on the 

 " Challenger " who pricked the bubble of " Bathybius " and 

 made known the real nature of that mythical organism. 



