128 THE OCEAN 



caying material from countless millions of 

 dead inhabitants of the sea. 



Of course the skeletons and shells of all the 

 marine creatures which die sink to the bottom 

 of the ocean, but the tiny diatoms and fora- 

 minifera so greatly outnumber all other forms 

 of ocean life that their remains are the most 

 in evidence in most places. So marvellously 

 abundant are these minute creatures that a 

 single ounce of sand sometimes contains over 

 three millions of their shells. In prehistoric 

 times the ancestors of these foraminifera were 

 even more numerous and their fossilised skel- 

 etons have formed the bulk of the chalk cliffs 

 of England, the building stone of Paris and 

 even the mighty blocks from which the Egyp- 

 tian pyramids were constructed. 



All this is very interesting when we give it 

 a thought, and it all goes to prove what a 

 wonderful thing the ocean and its life really 

 is, but to study ocean life at its best we must 

 look to the fairly shallow water on the great 

 submerged plateaus, the submarine mountain- 

 tops and reefs and near the coasts of continents 

 and islands. In such places the sea sustains 



