404 PACIFIC OCEAN. 
visited it; and states farther that the anchor, iron-works, and a large 
gun (4-pounder) of this vessel were two hundred yards inside of 
the line of breakers. Captain Beechey suggests that the coral had 
grown, and thus increased 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 consider certain,) 
it must have arisen from subterranean action. 
Tanitian Group.—The island of ‘Tahiti presented us 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 believing that any of them have been elevated. The 
change, however, of the barrier reef around Bolabola into a verdant 
islet encircling the island, may be evidence that a long period has 
elapsed since the subsidence ceased; and as such a change is not com- 
mon in the Pacific, we may suspect that it has been furthered by at 
least a small amount of elevation. The observation by the Rev. D. 
Tyerman with regard to tne shells found at Huahine high above the 
sea may be proof of elevation; but the former erroneous conclusions 
with regard to Tahiti, teach us to be cautious in admitting it without 
a more particular examination of the deposit. 
Hervey anp Rurutu Grours.—These groups he to the southwest 
and south of Tahiti. 
Atiu (Wateoo of Cook) is a raised coral island. Cook observes that 
it is “nearly like Mangaia.” ‘The land near the sea is only a bank of 
coral ten or twelve feet high, and steep and rugged. The surface of 
the island is covered with verdant hills and plains, with no streams.* 
Mauke is a low elevated coral island.+ 
Mitiaro resembles Mauke.t 
Okatutaia is a low coral island, not more than six or seven feet 
high above the beach, which is coral sand. It has a light-reddish soil. 
Mangaia is girded by an elevated coral reef three hundred feet in 
height. Mr. Williams speaks of it as coral, with a small quantity of 
* Cook’s Voyage, vol. i. pp. 180, 197. Williams’s Miss. Enterprises, i. 47, 48, first 
Am. edit., Appleton. 
+ Williams’s Miss. Ent., pp. 39, 47, 264. 
¢ Ibid. pp. 39, 264. 
