52 



BULLETIN : MUSEUM OF COMPARATIVE ZOOLOGY. 



Naiau. 



Plates 30, 32% Fig. 1. 



!N^aiau Island is, like Tuvutha, composed entii'ely of an elevated lime- 

 stone ridge forming a continuous rim round a central depression stated 

 to be about 200 feet lower than its highest points, which rise from 530 

 to 580 feet above the level of the sea. The sea face of the rim rises 



NORTH POINT OF NAIAU. 



in nearly perpendicular blufis round the island. At their base they are 

 deeply undercut, and the larger fragments are eroded into dome-like 

 heads. Off the southeastern point an islet has been isolated from the 

 island. Naiau is surrounded by a fringing reef broadest on the eastern 

 face, about half a mile wide, where at half tide boats can pass, between 

 it and the shore, forming an incipient lagoon, and enter through a 

 narrow boat harbor passage, out of which, I am informed by our pilot, 

 runs a strong current. Tliere are numerous negro-heads all along the 

 outer edge of the fringing reef, especially near the northwestern point of 

 the island, where the fringing reef is narrowest. 



Naiau,^ Tuvutha, Kambara, Wangava, and other elevated islands, 

 consisting of coralliferous limestone, have been considered to be elevated 





Jl-frilj^.llllM'' *l>iC^^-'- 



'^UnAiii,>UiimiiLV<hTiiiiiWiaur^iduliia& 



^V ' ' I'l' 



NAIAU, SEEN FROM THE EAST. 



atolls, owing to the existence of a depression in the summit, which is 

 looked upon as representing the former lagoon. While that may be the 



1 Moore, Nature, March 18, 1897, p. 463. Others have looked upon these islands 

 as extinct craters. 



