CORAL REEFS AND SUBMARINE BANKS 2m5 
coral reefs postulated an intermittent subsidence of the reef founda- 
tions; and, as the theory seemed true to its inventor, he based a 
second theory regarding the movement of the ocean floor upon the 
first, as will be further shown in the final section of this article. It 
is particularly to this oceanic corollary of the coral-reef theory that 
objection is made in the statement of the glacial-control theory on 
the ground of its supposed improbability. That theory therefore 
postulates “‘a long period of nearly perfect stability for the general 
ocean floor’’; and the action of subsidence is made subordinate if 
not excluded. Yet it must be clear that any slow and intermittent 
process of local subsidence associated with volcanic cones will serve 
the needs of Darwin’s theory just as well as a broad subsidence 
of the ocean floor; and in giving only a small value to such subsi- 
dence the glacial-control theory has, in my opinion, overlooked a 
very important factor of the problem. 
It is true that there is a large body of older geological opinion 
that regards volcanic areas as areas of elevation and hence objects 
to a theory of coral reefs that postulates the subsidence of such 
areas. Thus Guppy asserted that the occurrence of barrier reefs 
and atolls in association with active volcanoes placed “‘the sup- 
porters of the theory of subsidence in a dilemma.’’’ Hickson was 
persuaded that Passiac atoll, north of Celebes, could not have been 
built on a subsiding foundation, because an active volcano, Ruang, 
rises near by.2, Murray had earlier made a more extreme state- 
ment; he thought that even extinct volcanoes occupy areas of 
elevation, and that, if areas of subsidence occur in the ocean floor, 
they must lie between the ranges of volcanic islands. 
There is, on the other hand, a considerable body of more modern 
and better-based opinion which associates volcanic activity, in 
some cases at least, with subsidence, as I shall elsewhere show in 
more detail, and as will here be pointed out for Hawaii in a later 
paragraph. It is immaterial to reef-building corals whether the 
tH. B. Guppy, ‘‘A Criticism of the Theory of Subsidence as Affecting Coral Reefs,”’ 
Scot. Geogr. Mag., IV (1888), 121-37; see p. 136. 
2S. J. Hickson, A Naturalist in North Celebes (London, 1889), p. 42. 
3J. Murray, ‘On the Structure and Origin of Coral Reefs and Islands,’’ Proc. 
Roy. Soc. Edinb., X (1880), 505-18; see p. 516. 
