ELEVATION'S IN PACIFIC CORAL REGIONS. 335 



is eighty feet. It is one of the southeastern Paumotus, near 

 Ducie's. 



Ducie-s Island is described by Beechey as twelve feet high, 

 which would indicate a probable elevation of one or two feet. , 



Osnaburgh Island, according to the same author, affords evi- 

 dence of having increased its height since the wreck of the Matil- 

 da, in 1792. He contrasts the change from a " reef of rocks," 

 as reported by the crew, to " a conspicuously wooded island," 

 the condition when he visited it ; and states, further, that the 

 anchor, iron works, and a large gun (4-pounder) of this vessel 

 were two hundred yards inside of the line of breakers. Cap- 

 tain Beechey suggests that the coral had grown, and thus in- 

 creased the height. But this process might have buried the 

 anchor if the reef were covered with growing corals (which 

 is improbable), and could not have raised its level. If there 

 has been any increase of height (which we do not say is cer- 

 tain), it must have arisen from an upheaval. 



b. Tahitian Group. — The island of Tahiti presents no 

 conclusive evidence of elevation. The shore plains are said to 

 rest on coral, which the mountain debris has covered ; but 

 they do not appear to indicate a rise of the land. 



The descriptions by different authors of the other islands 

 of this group do not give sufficient reason for confidently be- 

 lieving that any of them have been elevated. The change, 

 however, of the barrier reef around Bolabola into a verdant 

 belt encircling the island, may be evidence that a long period 

 has elapsed since the subsidence ceased; and, as such a change 

 is not common in the Pacific, we may suspect that it has been 

 furthered by at least a small amount of elevation. The observa- 

 tion by the Rev. D. Tyerman with regard to the shells found at 

 Huahine high above the sea, may be proof of elevation ; but 

 the earlier erroneous conclusions with regard to Tahiti (on 



