ON THE FORMATION OF CORAL ISLANDS. 345 



discovering the very fact, or the cause ; but the follow- 

 ing islands afford the most convenient and satisfactory 

 proofs. 



If I take the Tonga islands as a convenient case for 

 this illustration, Tongataboo and Eeooa form the first 

 Jink in this chain ; and it is one which is peculiarly 

 valuable, from the great differences between the forms 

 of these two tracts of coral land under such a proxi- 

 mity. Eeooa, distant from the former only twenty 

 miles, consists of a hill of considerable elevation, 

 though that height is not given. But for the present 

 purpose, this omission is not of any moment; it is 

 sufficient that it displays coral three hundred feet 

 and more above the level of the sea, indicating, in the 

 most demonstrative manner, the former existence of a 

 force which must have raised it to that height. It is 

 also probable, from the proximity of these two islands, 

 that both were raised at the same time, and by the 

 same force ; the chief power having been exerted 

 under Eeooa, while the lower island of Tongataboo 

 was raised to a height, comparatively so inconsider- 

 able, because it lay on the boundary of the elevating 

 power. There is no other cause adequate to the 

 production of these effects ; as, of the effects of such 

 causes, I have given ample proof in a former chapter: 

 and it must be superfluous to say that if such a power 

 produced the greatest of these effects, it is also capable 

 of accounting for the least of them. 



It is true that there is no volcano actually existing 

 in Eeooa ; but if it can be shown that this force has 

 exerted its action in a manner so demonstrable that it 

 has actually erupted volcanic matter, or if there are 

 volcanoes now in existence in the same seas, and with 

 the same consequences, even to the existence of coral 

 high on the sides of the mountains, the inference is 



