268 THE OCEAN. 



ness, as all who have seen it testify, its structure, 

 on examination, is found to be no less interesting 

 and wonderful. The beach of white sand, which 

 opposes the whole force of the Ocean, is found to 

 be the summit of a rock which rises abruptly from 

 an unknown depth, like a perpendicular wall. The 

 whole of this rampart, as far as our senses can 

 take cognizance of it, is composed of living coral, 

 and the same substance forms the foundation of the 

 curved and more elevated side which is smiling in 

 the luxuriance and beauty of tropical vegetation. 

 The elevation of the coral to the surface is not 

 always abruptly perpendicular; sometimes reefs of 

 varying depths extend to a considerable distance 

 in the form of successive platforms or terraces. In 

 these regions may be seen islands in every stage 

 of their formation : " some presenting little more 

 than a point or summit of a branching coralline 

 pyramid, at a depth scarcely discernible through the 

 transparent waters; others spreading, like submarine 

 gardens or shrubberies, beneath the surface; or 

 presenting here and there a little bank of broken 

 coral and sand, over which the rolling wave occa- 

 sionally breaks ;" while others exist in the more 

 advanced state that I have just described, the main 

 bank sufficiently elevated to be permanently pro- 

 tected from the waves, and already clothed with 

 verdure, and the lagoon enclosed by the narrow 

 bulwark of the coral reef. Though the rampart thus 

 reared is sufficient to preserve the inner waters in 

 a peaceful and mirror-like calmness, it must not 

 be supposed that all access to them from the sea 



