Ill 



EXPEDITION OF THE "CHALLENGER" 83 



the Berlin Academy for the year 1853, of the 

 soundings obtained by Lieut. Berr3rtnan, of the 

 United States Navy, in the North Atlantic, 

 between Newfoundland and the Azores. 



Observations which confirm those of Ehrenberg 

 in all essential respects have been made by 

 Professor Bailey, myself, Dr. Wallich, Dr. Car- 

 penter, and Professor Wyville Thomson, in their 

 earlier cruises; and the continuation of the 

 Glohigerina ooze over the South Pacific has been 

 proved by the recent work of the Challenger, by 

 which it is also shown, for the first time, that, in 

 passing from the equator to high southern lati- 

 tudes, the number and variety of the Foramimfera 

 diminishes, and even the Glchigerince become 

 dwarfed. And this result, it will be observed, is 

 in entire accordance with the fact already men- 

 tioned that, in the sea of Kamschatka, the deep- 

 sea mud was found by Bailey to contain no cal- 

 careous organisms. 



Thus, in the whole of the " intermediate zone," 

 the silicious deposit which is being formed there, 

 as elsewhere, by the .accumulation of sponge- 

 spicula, Radiolaria, and Diatoms, is obscured and 

 overpowered by the immensely greater amount of 

 calcareous sediment, which arises fi:om the ags^re- 

 gation of the skeletons of dead Foraminifera. The 

 similarity of the deposit, thus composed of a 

 large percentage of carbonate of lime, and a small 

 percentage of silex, to chalk, regarded merely as a 



