Q4 PACIFIC ISLANDS. 
the ocean, not of coral origin, until we approach the East Indies and 
Asia, where granites and sedimentary rocks make their appearance. 
New Zealand has its granites, schists, and coal formation. New Cale- 
donia presents ridges of talcose rock, mica schist, and probably others 
of a sedimentary character; and many of the larger islands of Mela- 
nesia approximate in geological character to Australia and New 
Guinea. But according to present knowledge, through all Polynesia 
exclusive of New Zealand, throughout Micronesia, and a considerable 
portion of Melanesia, the six hundred islands are either basaltic or 
coral. Under the term basaltic we include the volcanic, as the latter 
differ only in having had the igneous action which originated them 
continued to a later period. 
The islands of the Pacific belong, then, tothree divisions : the coral, 
the basaltic or igneous, and the continental,—designating by the last 
term those which have the mixed geological character of the con- 
tinents. 
The coral islands of the ocean amount to 290, the basaltic to about 
350. The number of the third kind is doubtful, as the character of 
the various islands of the Salomon Group, and those adjoining, is not 
fully known. The large number of coral islands is an interesting fact, 
as we see from it how much the ocean and the world are indebted to 
the coral zoophytes. Were we to count, also, the many green spots, 
large enough for a village site, or a grove of palms, that occur on the 
reefs around the high islands, the number would be greatly aug- 
mented. The sea has lost some of its wonders by late observations 
on corals ; for they were believed by early travellers to build up their 
structures from the deep bottom of the ocean: and in view of the sup- | 
posed rapidity of the work, it was thought that navigation might soon 
be everywhere obstructed. Although these opinions have proved 
groundless, yet the facts may well surprise: for it is still true that 
these islands stand in an unfathomable ocean; and attempts to explain 
the congruity of this fact with the growth of corals only in shallow 
waters not exceeding a depth of 20 fathoms, called forth much specu- 
lation, before the truth was finally ascertained. 
The whole area covered by the coral islands of the ocean, is not far 
from 19,000 square miles. Yet the area of dry land in the whole, as 
we shall hereafter explain, is little more than one eighth of this amount. 
These islands constitute a large archipelago, northeast and east of 
the Society Islands, called the Paumotus ; the whole number is eighty- 
two, and all are of coral origin, excepting the Gambier Group and 
