ELEVATIONS IN PACIFIC CORAL REGIONS. 337 



With regard to the other islands of these groups, Manuai, 

 Aitutaki, Rarotonga, Rimetara, Tnbuai, and Raivavai, the de- 

 scriptions by Williams and Ellis appear to show that they have 

 undergone no recent elevation. 



d. Tonga or Friendly Islands, and others in their vicinity. 



All the islands of the Tonga group about which there are 

 reefs, give evidence of elevation : Tongatabu and the Hapaii 

 islands consist solely of coral, and are elevated atolls. 



Eua, at the south extremity of the line, has an undulated 

 mostly grassy surface, in some parts eight hundred feet in 

 height. Around the shores, as was seen by us from shipboard, 

 there is an elevated layer of coral reef-rock, twenty feet thick, 

 worn out into caverns, and with many spout-holes. Between 

 the southern shores and the highest part of the island, we ob- 

 served three distinct terraces. Coral is said to occur at a height 

 of three hundred feet. From, the appearance of the land, we 

 judged that the interior was basaltic ; but nothing positive was 

 ascertained with regard to it. 



Tongatabu (an island visited by us) lies near Eua, and is in 

 some parts fifty or sixty feet high, though in general but twen- 

 ty feet. It has a shallow lagoon, into which there are two en- 

 trances ; some hummocks of coral reef -rock stand eight feet out 

 of water. 



Namulm and most of the Hapaii cluster, are stated by Cook 



to have abrupt limestone shores, ten to twenty feet in height. 



Namuka has a lagoon or salt lake at centre, one and a half miles 



broad ; and there is a coral rock in one part twenty-five feet 



high. It is described by Williams, p. 296. 



Vavau, the northern of the Group, according to Williams 



(p. 427), is a cluster of elevated islands of coral limestone, 



thirty to one hundred feet in height, having precipitous cliffs, 



with many excavations along the coast. 

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