186 Reviews—The Coral Reef Problem. 
long remain the standard authority on a subject which possesses 
great geological interest and economic importance. Throughout 
it is clearly written and liberally illustrated. The Atlas contains 
a general map of the region and detailed geological maps of the four 
most important districts, together with a series of plates illustrative 
of technological processes. 
A. HARKER. 
Tue CoraL REEF PROBLEM AND THE EVIDENCE OF THE FUNAFUTI 
Borines. By EH. W. Sxeats. Amer. Journ. Sci., vol. xlv, 
1918. pp. 81-90. 
N this paper the author, who is highly qualified for the task, 
reviews the evidence afforded by the study of the material 
from the Funafuti bores in the light of recent developments in the 
study of coral-reefs, with special reference to the work of Daly and 
Davis. Incidentally, he makes the interesting statement that the 
experts who examined this material were not allowed to express 
in their reports any opinions as to the mode of formation of the 
atoll, but he believes he is correct in saying that they were unanimous 
in the conclusion that their results supported Darwin’s theory of 
subsidence, and, in fact, were fairly susceptible of no other known 
explanation. 
Three points specially dealt with in this paper are the submarine 
profile of Funafuti, Daly’s and von Lendenfeld’s views and diagrams 
of the development of atolls, and the mechanism of the filling of 
“lagoon moats”’. It is shown that all the core-material consists 
of shallow water organisms, mostly in the position of growth. No 
trace of deep- water, organisms was found in any part of the core 
down to 1,114 feet, and no stratification was detected such as is 
inevitable in a talus deposit. 
The filling of the so-called “ lagoon moat ”’ is shown to be due 
mainly to erowth of Halimeda and other organisms, sediment playing 
but a subsidiary part, and it is noted that measurements have shown 
that some lagoons are becoming shallower, which effectively disposes 
of Murray’s solution theory 
The general conclusion reached from this revision of the evidence 
is that the only cause capable of accounting for all the facts is sub- 
sidence. This is in exact accord with the opinion expressed by 
Professor Sollas in 1905, in a couple of notable essays on the results 
of the Funafuti expeditions. 
