300 THE ATLANTIC. [chap. v. 



the distribution of fishes seems to me to corroborate the view 

 that in a deep-sea vertical section there are two regions — one 



Fig. 62. — Chauliodus Sloanii, From the upper wiitei'. One third the uiitiiriil size. 



within a limited distance of the surface, and the other a little 

 M^ay above the bottom — which have their special faunae ; while 

 the zone between is destitute of, at all events, the higher forms 

 of animal life. 



In some places, both in the Atlantic and the Pacific, especially 

 at extreme depths in the red-clay are?e, the trawl brought np 

 many teeth of sharks and eai--bones of whales, all in a semi-fos- 

 sil state, and usually strongly impregnated with, or their sub- 

 stance to a great extent replaced by, the oxides of iron and man- 

 ganese. These deposits of bones occur at great distances from 

 land, and where from other causes the deposition of sediment 

 is taking place with extreme slowness. The sharks' teeth be- 

 long principally to genera, and often to species, which we believe 

 to be now extinct, and which are characteristic of the later Ter- 

 tiary formations ; and there seems little doubt that they have 

 been lying there, becoming gradually buried in the slowly ac- 

 cumulating sediment, from Tertiary times. The fishes which 

 were collected during the expedition are now undergoing ex- 

 amination by Dr. Giinther, and the semi-fossil remains from the 



