APPENDIX. 189 



of between two and three hundred yards ; coloured red. 

 Pitcairn Island, in the immediate neighbourhood, according 

 to the same authority, has no reefs of any kind, although 

 numerous pieces of coral are thrown up on the beach ; the 

 sea close to its shore is very deep (see Zool. of Beechefs 

 Voyage, p. 164); it is left uncoloured. Gambier Islands 

 (see Plate II., Fig. 5) are encircled by a barrier-reef; the 

 greatest depth within is 38 fathoms ; coloured pale blue. 

 Aurora Island, which lies N.E. of Tahiti close to the large 

 space coloured dark blue in the map, has been already 

 described in a note (p. 118), on the authority of Mr. 

 Couthouy; it is an upraised atoll, but as it does not 

 appear to be fringed by living reefs, it is left uncoloured. 



The Society Arch, is separated by a narrow space from 

 the Low Arch. ; and in their parallel direction they manifest 

 some relation to each other. I have already described the 

 general character of the reefs of these fine encircled islands. 

 In the Atlas of the Coquille's Voyage there is a good 

 general chart of the group, and separate plans of some of 

 the islands. Tahiti, the largest island in the group, is 

 almost surrounded, as seen in Cook's chart, by a reef from 

 half a mile to a mile and a half from the shore, with from 

 10 to 30 fathoms within it. Some considerable submerged 

 reefs lying parallel to the shore, with a broad and deep 

 space within, have lately been discovered (JVaut. Mag., 

 1836, p. 264) on the N.E. coast of the island, where none 

 are laid down by Cook. At Eimeo the reef " which like a 

 ring surrounds it, is in some places one or two miles distant 

 from the shore, in others united to the beach" (Ellis, 

 Polynesian Researches, vol. i. p. 18, i2mo edit.). Cook 

 found deep water (20 fathoms) in some of the harbours 

 within the reef. Mr. Couthouy, however, states {Remarks, 

 p. 45) that both at Tahiti and Eimeo, the space between 



