627 
1. R. A. Dary. A new test of the subsidence theory of coral reefs. 
Proc. of the Nat. Acad. of Sciences of the U. S. of America. Vol. II 
p. 664, 1916. 
In this paper Dary argues that the observed shallowness of the 
lagoons as well as the levelness of the great majority of the lagoon- 
floors do not seem to agree with a legitimate deduction from the 
subsidence theory of coral reefs, whereas the glacial control theory 
would afford a reasonable explanation. It seems to me even if we 
accept the glacial control theory, the principle of subsidence in accord- 
ance with Darwin’s theory need not neéessarily be abandoned. 
An atoll, e.g. the Funafuti atoll, may have been formed under 
conditions of local subsidence in accordance with the hypothesis 
explained above, in a time preceding the pleistocene glacial period. 
During the glacial period the atoll with its moat more or less filled 
may have been truncated in consequence of the lowering of the 
sea-level to a level about 50—60 metres below the present sea-level. 
By this truneation the lagoon-floor attained its levelness, which it 
has on an average maintained until the present day, although on its 
rim a new growth of corals has since the close of the glacial 
period again built up an atoli-shaped reef structure, the visible portion 
of which determines the shape of the present Funafuti-atol. 
2. A. Lacroix. Le soi-disant granite de Vile Bora-Bora. C. R. des 
séanees de la Soc. Geol. de France. Séance du 18 Décembre 1916, 
DN 178: | 
In this paper Lacrorx proves that the supposed granite (according 
to Ellis) of the island of Bora-Bora in the group of the Society 
Islands, is in reality not a granite at all, but a medium-grained 
olivine-gabbro, an intrusive facies of a basaltic rock, of which the 
greater part of the island consists. 
Bora-Bora is a true oceanic island encircled by a beautiful barrier 
reef and if it were indeed composed of granite this fact, to quote 
Lacroix, ,,entrainerait d’importantes conséquences au point de vue 
theorique’’. 
Lacroix, however, now has done away with the myth of the 
occurrence of granite in the Society Islands, and the island of Bora- 
Bora thus only confirms the rule, which we have accepted, that 
true oceanic islands are composed of volcanic rocks. 
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