THE KEELING ISLANDS. 



55 



coralline tower, slowly built up by the polyps as the base of the structure slowly 

 subsided. Since the preparation of the first chart of the group, indications of 

 upheaval have been observed The beach has been raised and enlarged, some of 



Fig. 19. — Keeling Islands. 

 Scale 1 : 135,000. 



'96"50' 



Lcisb oh b'^eenwich 



96°56' 



Depths. 



mm 



Sands and reefs ex- 

 posed at low water. 



0to64 

 Feet, 



64 to 6,400 

 Feet. 



6,400 Feet and 

 upwards. 



3 Miles. 



the channels have been closed, and lagoons formerly communicating with the open 

 sea are now inaccessible to shipping. 



The atoll, which is interrupted by numerous breaches, and which opens out 

 broadly towards the north, consists of some twenty elongated islets occupying at 

 high water a total space of about six square miles. The only spontaneous growths 



