IN THE COCOS'KEELING ISLANDS. 



35 



CHAPTER IIL 



SOJOURN m THE COCOS-KEELIXG ISLANDS 



ued 



Coral reef formation — Observations on the elevation (5r%jttbsidenceof the 



Keeling atolL 





As the Keeling atoll was the reef most carefully examined and 

 described by Mr. Darwin, and that with which, in propounding 

 his famous theory of coral reefs, he has compared the others he 

 describes, I felt specially pleased at being able to go over 

 his own ground with his book in my hand, and gain a clearer 

 understanding of several points whicli I had found it difficult 

 to comprehend. 



Unf< 



visit was not suffi- 



ciently favourable to enable me to examine so closely as I 

 could have desired the corals of the outer margins or to make 

 the series of seaward soundings I had intended. 



The first questions that present themselves to the traveller 

 in midst of his amazement on first reaching that peculiar 

 production of the warm seas— an island-speckled ring of coral 

 holding its own against the waves— are, How came it into being 

 here, AVhy of this singular form, and How does it continue to 

 exist ? Mr. Darwin was the first to attempt any far-reaching 

 solution of these difficult questions, applicable to coral forma- 

 tions over all the world. As true reef-building corals, it is well 



tnown, can flourish only beneath a very limited depth— some 

 twenty fathoms— of water, a great apparent difficulty existed 

 "respecting the foundations on which these atolls are based, 

 from the immensity of the spaces over which they are inter- 

 spersed and the apparent necessity for believing that they are 

 all supported on mountain summits, which, although rising very 

 near to the surface of the sea, in no one instance emerge alwve it. 

 To escape this latter most improbable admission, which implies 

 the existpnnpv r>f cTiLmnr;nn nlini'ns nf mountaius of aliuost the 



