OCEAN DEPOSITS: RED CLAY 37 



before it is carried very far from land ; but are not 

 the shells of Foraminifera, and Pteropods, and Radio - 

 laria, and Diatoms, always being showered down ? The 

 answer is, that these shells are, indeed, falling every- 

 where, and that although in water that is not too 

 deep they reach the bottom safely and cover each 

 other up, yet in the abysses of the ocean they are 

 either dissolved or otherwise destroyed before they 

 get to the bottom. The Pteropod and Foraminifera 

 shells, which consist of carbonate of lime, are dissolved 

 by the sea-water, and may disappear completely, but even 

 the resistent Radiolarian and Diatom shells, though 

 they are not completely dissolved, yet at last get 

 broken and chemically altered, until finally, there is 

 little left to fall in the great depths of the ocean 

 but the settling volcanic dust. 



This sketch, for the materials of which I am 

 indebted to the published researches of Sir John 

 Murray and the Challenger, must serve for an idea of 

 the bed of the ocean, and we may now go on to 

 consider, in a general way, the peculiar conditions of 

 life in the ocean depths. 



Many people know the sensation of diving to the 

 bottom of a swimming-bath ; it is felt in the drum of 

 the ear, where the increased pressure of only a few 

 feet of water gives rise to a painful feeling of tension. 

 At the surface of the water, as everyone knows, the 



