TETIAEOA. 167 



the mountain constituting the nucleus from which has been eroded the 

 submarine platform upon the outer rim of which a circle of islands has 

 been thrown up, rises to a height of over 2400 feet, while in Maupiti it 

 does not rise to more than 800 feet ; and in the last the central peaks have 

 been completely eroded, leaving only the volcanic submarine platform, on 

 the outer rim of which the coral sand islets and islands have been thrown 

 up and have enclosed a shallow lagoon. 



Disintegration and erosion are quite sufficient to account for the difference 

 of condition of these three island groups without having recourse to special 

 elevation or to individual subsidence. 



Motu Iti and Tetiaroa represent, in the Leeward and Windward Society 

 Islands, groups of coral reefs analogous to the low coral islands to the north- 

 east of Nukuhiva ; they hold to the high islands of the Society group, such 

 as Tahiti, Murea, Huaheine, Bora Bora, and others, much the same relation 

 which the low islands of the Paumotus, like the Duke of Gloucester Islands, 

 Pinaki, Hikueru, Hao, Takume, and others, hold to Makatea, Niau, and 

 Rangiroa. 



