CORAL REEFS AND SUBMARINE BANKS 4AIl 
Pacific was a supplementary idea which now proves to be erroneous 
because it was based on faulty or incomplete observations quoted by 
Darwin from the reports of other explorers. 
Darwin’s coral-reef theory itself simply postulates that reefs 
are formed by upgrowth, whenever and wherever fitting foundations 
in an ocean of proper temperature subside at a proper rate. This 
theory now needs subordinate modification by compounding the 
periodic changes of ocean-level during the glacial period with the 
changes due to subsidence and elevation; but the theory needs no 
change because Fiji is shown not to be an area of simple subsidence; 
indeed the theory is more strongly supported than ever, now that it 
is found to hold good, not only for areas of simple subsidence, but for 
an area of complicated oscillation such as Fiji proves to be. 
It is only the over-simple supplementary theory regarding the 
Pacific that is negatived by the new observations; that theory 
must be replaced by a newer and more complicated theory of the 
Pacific, which may well include relatively local subsidence of active 
or recently active volcanoes, as intimated in an earlier section, as 
well as ocean-floor deformation of any kind, local or widespread, 
dependent or independent of volcanic action; but such a theory of 
the Pacific does not demand any modification whatever in the theory 
of reef upgrowth on slowly or intermittently subsiding foundations; 
tor, as Darwin put it, ‘‘during a gradual subsidence the corals would 
be favorably circumstanced for building up their solid frameworks 
and reaching the surface, as island after island disappeared” (94), 
to whatever process the subsidence might be due. That elastic 
theory, with its various special adaptations to special conditions 
as stated by Darwin, and modified as need be by combining changes 
of ocean-level with subsidence of reef foundations, still seems to 
me to give a better explanation than any other for the various and 
complicated phenomena of coral reefs. Molengraaff’s recent sug- 
gestion’ that the subsidence, which determined the formation of 
most atolls, has resulted from the local and isostatic sinking of 
their volcanic foundations is an important contribution to the 
problem, which I have briefly considered elsewhere.’ 
“The Coral Reef Problem and Isostasy,’’ Proc. k. Akad. Wet. Amsterdam, XIX 
(1916), 610-27. 
2“'The Isostatic Subsidence of Volcanic Islands,”’ Proc. Nat. Acad. Sci., III (1917) 
649-54. 
