THE ROCKS AND THEIR STORY 9 



Funafuti, a deep boring has been made 1,114 ft. deep. 

 As far as the boring went all was coral. All this mass of 

 coral is formed by living things, polyps they are called. 

 They are like tiny sea anemones, only they grow attached 

 to one another, forming a compound animal, like a tree 

 with stem and branches, and little sea anemones for 

 flowers. The whole organism has a sort of shell or skeleton, 

 which is the coral. Blocks are broken off by the waves, 

 and ground to a coral mud, which fills up the interstices 

 of the coral ; and as more coral grows above, the lower 

 part of the reef becomes, by pressure and cementing, a solid 

 coral limestone. Once upon a time there were coral 

 islands forming in a sea, where now is England. These 

 old coral reefs form beds of limestone in Devon, Derby- 

 shire, and other parts of England. In the Isle of Wight 

 we have no old coral reefs, but we shall easily find fossil 

 corals in the rocks. They helped to make up the rocks, 

 but there were not enough here to make reefs or islands 

 all of coral. 



The great branching corals that form the reefs can only 

 live in warm waters. So we see that when corals were 

 forming reefs where now is England the climate must 

 have been warm like the tropics. That is a story we 

 shall often read as we come to hear more about the rocks. 

 We shall find that the climate has often been quite warm 

 as the tropics are now : and we shall also read another 

 wonderful story of a time when the climate was cold like 

 the Arctic regions. 



