52 On the Formatiop. and Growth of Coral Reefs and Islands. 



The islands Raiatea and Taliaa, UUietea and Otaha of Cook, are divided 

 by a strait, by which ships can enter at the windward side of tlie island, 

 and get to sea again through the leeward channels. These two islands are 

 entirely surrounded by one coral reef, extending throughout the circum- 

 ference of both ; the o])enings through the reef are in most cases denoted 

 by the points being rather higher and often verdant, having trees, princi- 

 pally cocoa nut trees, planted by the natives upon them. The passage is 

 seldom more than a hundred yards in breadth, with the depth varying 

 from three to fifteen fathoms. 



The form of all coral islands musi very materially depend upon that of 

 the base on which they happen to be built, therefore we must assume a 

 form of substructure corresponding with the peculiarity of the formation 

 we are investigating. We have thus enumerated several formations differ- 

 ing essentially from each other. 



Although, in common with all animated creatures, the polypes possess 

 certain instinctive powers, yet so constant are their results, that under 

 whatever circumstances they may be placed, their actions and mode of 

 growth are the same ; therefore it is evident, that the form of the reefs 

 produced are not so much dependant upon the architectural design of the 

 builders, as upon the form of the basis they may have to build upon. 



Let us for a. moment imagine the water to have left that portion of the 

 ocean in which these islands abound, and what might we presume would 

 be their appearance ? should we not iiave mountains of various degrees of 

 elevation ? And is it not as likely that the majority of these mountains 

 should be of volcanic origin, as that the present country of Auvergne, 

 Italy, or Mexico, should exhibit evidences of volcanic action long since 



except at particular seasons, vvlien it is visited by the Tahitian nobility and invalids, 

 as a place of recreation and fashion, similar to our watering places ; and it is here 

 that the ladies sojourn dming the fattening season, just previous to their national 

 annual meetings ; for in this part of the world, height and weight are essential to 

 enable them to carry off the palm of beauty. 



