Into the Depths 295 



pressure of the water — over three tons to the square 

 Inch — must make motion of all kinds extremely slow; 

 and such fishes as are found living there are adapted to 

 withstand this environment by having bodies so soft 

 and delicate in structure that when brought to the sur- 

 face they cannot be touched without injuring them. 

 Plant life, except, perhaps, bacteria or other low fun- 

 goid forms, Is entirely absent. The composition of the 

 floor is made up of the material that filters down from 

 above; these deposits, of course, varying according to 

 the nature of the organisms at the surface; thus, where 

 those protozoans known as Globigerina prevail, the 

 ooze at the bottom is composed of carbonate of lime; 

 where organisms which secrete silica abound, we find 

 the floor underneath consisting of radlolarlan or diatom 

 ooze. However, in the very deepest parts of the ocean 

 the calcareous organisms are removed by solution, and 

 In some places siliceous remains are partly removed. 

 In certain regions of the South Pacific Ocean far re- 

 moved from the continental land, naturalists have 

 brought up in their trawls hundreds of sharks' teeth 

 and numerous ear bones of whales, some of which 

 belong to species now extinct. Chondrites, too, which 

 are found only in meteorites, and, mixed with the clay, 

 magnetic spherules of metallic iron and nickel, and tons 

 of manganese nodules were among the hauls. This 

 abundance of teeth and bones and extraterrestrial ob- 

 jects in those remote depths is owing to the fact that 

 few other materials reach those regions to cover them 

 up, as In other deposits. From this may be gathered 

 some Idea of the slow rate at which the floor deposits 

 accumulate; probably not more than a foot since the 



