2l6 HISTORY OF GEOLOGY AND PALEONTOLOGY. 



sediments, it does not enter into the consideration of deep-sea 

 deposits. The samples brought by Captain Brooke, in 1857, 

 from the Kamtschatka Sea, at depths between 900 and 2,700 

 fathoms, were examined by Bailey, who demonstrated the 

 existence of abyssal pelagic sediments composed of the 

 shells and skeletons of Foraminifera, Radiolarians, and Di- 

 atoms. Similar deposits at smaller depths had already been 

 proved by the researches of Ehrenberg, Joseph Hooker, and 

 Pourtales. In 1857, soundings were commenced in the 

 Atlantic Ocean, when it was desired to establish cable com- 

 munication between the Old and the New Worlds. Samples 

 of the deposits of the ocean-floor were given to Huxley by 

 Captain Dayman, and the examination of these resulted in an 

 accurate description of Globigerina Ooze. Between 1860 and 

 1870 many soundings and dredgings were taken in the Atlantic 

 Ocean, and the reports of Wyville Thomson, Carpenter, and 

 Pourtales added valuable scientific information about the 

 pelagic faunas and sediments. 



Oceanography was signally advanced by the results of the 

 Challenger Expedition. The English ship Challenger sailed 

 for four years (1872-76) on a voyage of exploration of the 

 great ocean basins. The material brought, home was investi- 

 gated and reported upon by the most eminent scientific 

 specialists of the day. The final report by Murray and Renard 

 (London, 1891) contains an exhaustive exposition of the 

 whole field of modern knowledge regarding pelagic deposits. 

 A comparison of this masterly work with that of Delesse, 

 shows what a grand accumulation of new facts had been 

 obtained during the twenty years that had elapsed, and 

 more especially how deep a debt of gratitude science owes 

 to the promoters and enthusiastic workers of the Challenger 

 Expedition. 



In the Challenger Report all deep-sea deposits are classed 

 as "terrigenous" or "pelagic" in origin (ante^ p. 183). The 

 former are distributed for the most part along the coast-line, 

 upon a shallow submarine platform adjacent to the shore, and 

 a gentle slope descending to lower depths. The pelagic 

 deposits owe their origin partly to the organic world, partly 

 to submarine volcanoes, and cover the floor of the open 

 ocean. All the different kinds of sediment are described in 

 the Challenger Report macroscopically, microscopically, and 

 chemically; their exact occurrence is entered upon maps of 



