NUKUTAVAKE. 



119 



high as the highest trees, and show well how in this island the depression 

 or sink, or the so-called lagoon, is produced by the enclosing of an area 

 within the space of coral sand or shingle beaches thrown up from opposite 

 sides. The highest sand dune we saw was fully 35 feet from the high -water 

 mark, and had greatly encroached upon the adjoining vegetation of the 

 outer rim of the island. Stumps of bushes and of trees could be seen pro- 

 truding from the sides and summit, and long stretches of trees near the 

 coast line were killed, the lower part of the trunk having been buried in 

 the sand (PL 70, fig. 4). 



The old ledge rock crops out on both sides of the island, but much of the 

 old ledge, however, is concealed by the overlying beacli rock, which extends 

 across the island, together with decomposed coral boulders and coral shingle ; 

 this, mixed with algte and dead leaves and bushes, forms an excellent light 

 soil on which is found growing in the interior fine Poukas, Pandanus, and 

 other characteristic coral reef vegetation (PI. 71). 



Following the line of the horn of the western extremity, th'ere is a well- 

 defined secondary lagoon parallel to the outer edge of the reef platform 

 (PL 70, fig. 3). 



NaTIVK at AkI-Aki in CaNOK, in which HK was blown from a WlNDWAltD 



Island a Couple of Hundred Miles. 



