342 On Coral Reefs and Islands. 
voleanic action among them. Some of them are elevated coral 
islands, as’ Mitiaro, Atiu, Mangaia and Mauki, and also, according 
to Stutchbury, Rurutu. Okatutaia is a low coral island but six 
or seven feet out of water. © 
Between the Paumotus and the longitude of Samoa, are nu- 
merous small islands, all of coral origin. 
Samoan Islands have extensive reefs. About Tutuila 
they are somewhat less extensive than around Upolu, owing to 
its abrupt shores; and about Savaii they are still smaller, as 
already explained. The influence-of abrupt shores may also be 
in some parts of Upolu; for example, to the west of the 
harbor of Falifa, where, for several miles, there is no reef, except 
in some of the indentations of the coast. Manua is described as 
having only shore reefs.* é . 
The Tonga Islands, south of Samoa, for the most part, abound 
in coral reefs, and Tongatabu and the Hapai Group are solely of 
coral a is a moderately high island, with a narrow reef. 
Tafoa, an active volcano, and Kao an extinct cone, are without 
reefs. Vavau, according to Williams,+ is an elevated coral island. 
Pylstaarts, near Koa, isa naked rock, with abrupt shores, an 
litle or no coral. Sunday Island, farther south, (29° 12’ S.,) is 
beyond the coral-reef limits. 
orth of Samoa are several scattered islands of small size, all 
of coral. ; | 
three Carolines, Ascension or Banabe uyni of Lutke,) 
Ualan, oie anes “var be, (Pouynipete 
The westernmost of the Sandwich Islands, Kauai and Oahu, 
have fringing reefs, while eastern Maui and the island of Hawail 
have but few traces of corals. On Hawaii, the only spot of reef 
seen by us, was a submerged patch off the southern cape © 
Hilo Bay. We have already attributed the absence of corals to the 
volcanic character of the island: ‘The small islands to the north- 
ee 
* Narrative Expl. Exp., by C. Wilkes, U.S, N. ii 
¢ Miss. Raterpes, p- 121, Amer. ed, ae 
