290 COOK'S VOYAGE TO APRIL, 



branches, are, in such a climate, soon converted 

 into a true black mould, or soil.* 



Perhaps there is another cause, which, if allowed, 

 will accelerate the increase of these islands as much 

 as any other; and will also account for the sea having 

 receded from those elevated rocks before mentioned. 

 This is, the spreading of the coral bank, or reef, into 

 the sea ; which, in my opinion, is continually, though 

 imperceptibly, affected. The waves receding, as the 

 reef grows in breadth and height, leave a dry rock 

 behind, ready for the reception of the broken coral 

 and sand, and every other deposit necessary for the 

 formation of land fit for the vegetation of plants. 



In this manner, there is little doubt, that, in time, 

 the whole reef will become one island; and, I think, 

 it will extend gradually inward, either from the in- 

 crease of the islots already formed, or from the 

 formation of new ones, upon the beds of coral, within 

 the inclosed lake, if once they increase so as to rise 

 above the level of the sea. 



After leaving Palmerston's Island, I steered west, 

 with a view to make the best of my way to Anna- 

 mooka. We still continued to have variable winds, 

 frequently between the north and west, with squalls, 

 some thunder, and much rain. During these showers, 



* Mr. Anderson, in his journal, mentions the following par- 

 ticulars, relative to Palmerston's Island, which strongly confirm 

 Captain Cook's opinion about its formation. " On the last of the 

 two islots, where we landed, the trees, being in great numbers, had 

 already formed, by their rotten parts, little risings or eminences, 

 which, in time, from the same cause, may become small hills. 

 Whereas, on the first islot, the trees being less numerous, no such 

 thing had as yet happened. Nevertheless, on that little spot, the 

 manner of formation was more plainly pointed out. For, adjoining 

 to it, was a small isle, which had, doubtless, been very lately 

 formed; as it was not, as yet, covered with any trees, but had a 

 great many shrubs, some of which were growing among pieces of 

 coral, that the sea had thrown up. There was still a more sure 

 proof of this method of formation a little farther on, where two 

 patches of sand, about fifty yards long, and a foot or eighteen 

 inches high, Jay upon the reef, but not, as yet, furnished with a 

 single bush or tree." 



