THE PAUMOTUS. 9 



trades had a great influence in shaping the land rim of one face, while the 

 other was only a half-drowned reef flat, often wholly under water. He 

 sounded lagoons from 20 to 38 fathoms, and from such information as 

 he gathered inferred that there had been, according to the statements of 

 the natives, very little change in the depth of the passages. He noticed 

 the effect of the wide outer-reef platform in regulating the How of the 

 sea into the lagoons over submerged parts of the rim and between 

 the gaps of low islands forming the land rim. He observed that the 

 height of the water in the lagoons was subject to the strength of the 

 trades, which influenced greatly the strength of the currents and their 

 direction through the passages. While examining Bow Island (Hao), he 

 observed the nature of the bottom of the lagoon and the growth of the 

 coral knolls scattered througliout its area. 



Beechey's ideas on the structure of coral reefs are interesting, and are 

 well illustrated b}' a diagram and sketch of Pinaki (Whitsunday),' which is 

 accompanied by an excellent description of the island. That diagram and 

 sketch have been very generally copied in all books on geography, so that 

 Whitsunday has unfortunately obtained a wide recognition as a typical atoll. 



There are scattered throughout Wilkes' '-'Narrative of the United States 

 Exploring Expedition" many accurate observations and shrewd remarks on 

 the formation of coral reefs. I may especially refer to Wilkes' disappoint- 

 ment on landing on a coral island.^ His account of its barrenness is in 

 marked contrast to the poetic descriptions which have been handed down 

 by so many writers on coral reefs. 



Wilkes^ gives also a sketch of Clermont-tonnerre, and the results of 

 soundings made off the east side of the atoll. At 300 feet from the edge of 

 the reef he obtained 90 fathoms ; at 180 feet 85 fathoms ; at 130 feet 7 

 fathoms. At three quarters of a mile from the southern point the "Peacock " 

 sounded in 350 fathoms. He gives a short list of the principal trees and 

 shrubs, and speaks of the number of birds on the islands as incredible. 

 The lagoon of Raraka was sounded ; * 30 fathoms was found inside a short 

 distance from the entrance, where the water is from five to eight fathoms. 



1 Beechev, loc. cit., pp. 188-193. s Lnc. cit., p. 311 of Vol. I. 



■^ Loc. cit., p. 317, Vol. I. of the Narrative. * Loc. cit., p. 331. 



