206 W. M. DAVIS 
fathoms in the glacial epochs. All such reefs appear to me to 
demand subsidence for their explanation; but as they all occur 
in the Western Pacific, and not in the central area where only 
atolls prevail, they do not bear directly on the atoll problem. All 
that can be said of such unconformable reefs and of the uplifted 
and dissected atolls of Fiji is that their evidence is highly favorable 
to Darwin’s theory, and that it is in some degree irrelevant to the 
origin of open-ocean atolls, which are the main subject of the glacial- 
control theory. . 
As far as my reading goes only three sections have been pub- 
lished in which the foundation of an actual coral reef is represented 
as a truncated volcanic mass. One section is of the island of 
Mango, Fiji, as interpreted by E. C. Andrews; the truncated sur- 
face is represented as covered by a now elevated coral reef into 
and over which later volcanic rocks are erupted; the section is 
reproduced as if authentic in de Margerie’s translation? of Suess’s 
Antlitz der Ende; but, as the surface of truncation 1s drawn below 
present sea-level and as the accompanying text gives no sufficient 
evidence of its existence, it must be regarded as hypothetical. My 
brief visit to the island did not enable me to examine its structure 
closely; but nothing that I saw gave any support to the theory of 
its having suffered truncation before its elevated reef was formed, 
nor did it appear to me that the elevated reef is older than the 
volcanic rocks that are associated with it. If the island really has 
been completely truncated, it constitutes a remarkable exception 
to the rule prevailing in Fiji, where the other volcanic islands have 
not been cut back enough to form strong shore cliffs. 
A second section of a truncated volcanic island is to be found in 
Pirsson’s account of the recent boring at Bermuda,’ where volcanic 
rocks were reached at a depth of 245 feet below sea-level and pene- 
trated to a depth of 1,278 feet. It appears to me regrettable that a 
single boring of this kind should be accepted as giving sufficient 
«—. C. Andrews, ‘‘The General Geology of the Fiji Islands .... ,” Bull. Mus. 
Comp. Zool., XX XVIII (1900), 1-50. 
2 La Face de la Terre, III (1913), 1061. 
3L. V. Pirsson, ‘‘Geology of Bermuda Island; the Igneous Platform,’ Amer. 
Jour. Sci., XXXVIII (1914), 189-206. 
