in the Pacific, (^c. "95 



yond which rises the fragmentary ridge, composed of large 

 blocks of reef-rock, having their interstices filled with a rub- 

 ble consisting of small fragments of coral, shells, and Echini, 

 cemented together so firmly as to require a smart hammer- 

 stroke for their separation. It has an elevation of from three 

 to ten feet, and varies in width, even on the same island, from 

 one hundred and twenty feet to one thousand yards. It is 

 highest on its seaward side, where it rises somev/hat abruptly, 

 but shelves very gradually towards the low, sandy shores of 

 the lagoon. There is rarely much vegetation till the summit 

 is crossed, but thence inland it frequently flourishes luxuri- 

 antly to the very brink of the water. This elevated tract 

 seldom if ever entirely surrounds the lagoon. I do not re- 

 member having seen a single Paumotu, which had not, on 

 one side, a considerable space of low, naked reef, or detached 

 masses of rock, over and between which, the sea at high 

 water broke into the lagoon. At Raraka, on the southern 

 side, to the westward of the passage between this and the 

 sea, where the upper plateau is rather narrower than common, 

 the ridge was of a character entirely diiferent from what 

 was observed at any other island, being mostly a heap of 

 loose rubble, eight or ten feet high, and perhaps a hundred 

 yards in breadth at the base, nearly as sleep on the inland as 

 on the seaward side, and destitute of any trace of vegetation. 

 Just inside of this ridge, were numerous shallow pools of salt 

 water, ebbing and flowing with the tide, and abounding in 

 Ophiuroe, Cidarites, Fistularias and Actinias. A large species 

 of Melampus was so plentiful among the fragments at the 

 base of the ridge, that it could be collected by handfuls. Be- 

 yond the pools was a plain of coral, which I estimated to be 

 a large mile across to the lagoon, but had no opportunity of 

 ascertaining it by actual measurement. It appeared to have a 

 very slight ascent from the sea, and was tolerably well cloth- 

 ed with trees and shrubs, though the species were few in 

 number. A few cocoa-trees only were seen, and those had, 

 as the inhabitants (about thirty Chain Islanders, engaged in 

 collecting pearl shells,) stated, been introduced recently by 

 themselves. 



