TAEITAEI. 269 



or five feet above high-water mark ; when this shingle has been pounded into 

 more or less coarse sand, vegetation begins to grow (PI. 157, fig. 2), and the 

 islands and islets thus formed become connected, until a large island is 

 formed by the union of the smaller ones (PL 157, fig. 1). In this way the 

 land rim of Taritari, which on the south shore is composed of two larger 

 islands of no less_ than eight and six miles in length (Pis. 152, figs. 3, 4 ; 

 155, fig. 1), was undoubtedly formed. Here and there indistinct gaps still 

 exist to indicate the nature of the changes which have taken place, and are 

 still going on at the eastern, northern, and part of the southern faces. 



Numerous shoals and coral patches exist in every part of the lagoon 

 we examined (PI. 224, fig. 4). On the slopes of the shoals large heads 

 of the different species of corals mentioned above are seen to a depth 

 varying from ten to sixteen fathoms ; here, as elsewhere, the number 

 of species which flourish in the lagoon is comparatively small. We exam- 

 ined no less than six of these little sand islets, on our way to Keuea. 

 According to the chart of Taritari^ (PI. 224, fig. 4), the lagoon to the north- 

 ward is full of ledges, shoals, and islets ; we passed through a number on our 

 way to the anchorage, and while in the atoll could see them rising against 

 the horizon in all directions and again when steaming along the west face 

 of Taritari (PL 154, fig. 3). 



Passing out of the western channel of Taritari, we had the opportunity 

 of noticing the structure of the land rim of the northwest point of the atoll ; 

 we could see that the islets on the outer edge of the reef flat were forming 

 at right angles to its general trend (PL 224, fig. 4), as sand spits extending 

 towards the lagoon, flanked on the sea face by ledges and boulders of beach 

 rock or coral conglomerate, while the lagoon end of the spits consisted of 

 fine coral sand. We observed nothing of special interest on the west face 

 of Taritari. 



Napuni Island is a long narrow island (PL 224, fig. 4), or rather a sand 

 spit with rocky ledges ; it extends north and south a distance of nearly 

 two miles on the sea face of the wide outer reef flat. Beach rock coral 

 conglomerate and boulders characterize its sea face, while shingle and coarse 

 sand are thrown up on the lagoon beaches. 



1 A. Chart 732. 



