THE PAUMOTUS. 17 



hard as calcite, full of corals, honej'combed and pitted, and undercut by the 

 action of the waves both on the lagoon side and on the sea face, worn into 

 countless spires and spurs and needles and blocks of all sizes and shapes, 

 separated by deep crevasses or pot-holes, recalling a similar scene in Ngele 

 Levu on the windward end of the lagoon. The reef fiat or shore platform 

 of many of the Paumotu atolls is strewn here and there with huge masses, 

 outliers of the ledge of elevated reef rock, or torn from its outer edge.' 

 Similar rocks and boulders occur on the lagoon side of the islands, forming 

 their outer land rim ; they are either torn oflF from the lagoon face of the 

 outcropping ledge, or are outlying parts of the ledge which have remained 

 in place and have not been planed down to the base level of the reef. 



The amount of water which is forced into the larger lagoons such as 

 Rangiroa over the flats of the weather side is something colossal, and when 

 we observe that there are often but a small number of passages through 

 which it can find its way out again on the leeward side, it is not surprising 

 that we should meet with such powerful currents, seven to eight knots in 

 several cases, sweeping out of the passages on the lee side. 



The islands and islets of most of the Paumotus are fairly well covered 

 with low trees and shrubs and large groves of cocoanut trees. 



The land rims are formed by material piled up both from the lagoon side 

 and the sea face. — material derived from the disintegration of the underly- 

 ing tertiary limestone, which crops out here and there along the sea fixce 

 and the inner shores of the lagoons. The islets and islands of the land 

 rim are more or less connected by outliers of the elevated limestone ledge, 

 attesting its greater extension in past times. 



Some of the islands appear to have been formed by accretion of sand 

 from the decomposing ledges of the lagoon. The outer land rim sometimes 

 appears as if formed by sand banks driven in from the sea face and also 

 driven out from the lagoon side by the action of the waves. It is evident 

 that shallow lagoons could readily be closed by such a process and the sea 

 no longer have access to it. 



It was with great interest that we approached Makatea, as it is the only 



' I am informed that enormous outliers of elevated coralliferous limestone fully 30 feet in liciglit 

 occur on the south side of Kaukura. 



