THE OCEAN UNEXPLORED AND UNEXPLOBABLE 251 



because I wished to deal with them as a whole. In 

 the face of the acute controversies which have taken 

 place between great authorities upon the subject of 

 coral reefs, it would be impertinent of me to intrude 

 any personal opinions of my own. But one thing is 

 certainly most clearly established, which is, that as 

 the madrepore or millepore, or, to use a more popular 

 and therefore incorrect term, the coral insect dies 

 when it reaches the surface, so it is unable to exist 

 below a certain depth of only a few fathoms. There- 

 fore the fanciful idea of these tiny builders toiling 

 through the ages in order to erect their babel towers 

 from the remote ocean depths until they reach the 

 surface to form islands must, however reluctantly, be 

 abandoned. Where it has been found that coral 

 persists to a great depth, it has also been found that 

 it is dead coral; that is, the tiny builders have 

 succumbed upon the sinking of the basement or 

 foundations of their erection a settlement in all 

 probability due to the shrinkage of the earth from 

 cooling, before alluded to. But where the coral 

 structures have been found to exist well above high- 

 water mark, it must be presumed that they have been 

 lifted thither by some subterranean upheaval as rapid 

 in its action as the sinking before mentioned had 

 been slow. 



The main feature, however, about the coral forma- 

 tions which strikes the imaginative mind is the 

 manner in which each of these tiny globules of jelly, 

 in whom only the microscope can enable us to observe 

 any of the organs we usually associate with constructive 

 life, labour incessantly to abstract from the sea as it 

 flows past them the particles of lime necessary to 



