VOLUME XXVI NUMBER 4 
THE 
JOURNAL OF GEOLOGY 
MAY-JUNE 1918 
CORAL REEFS AND SUBMARINE BANKS 
W. M. DAVIS 
Cambridge, Massachusetts 
PART II 
Fundamental postulates of the glacial-control theory.—It we now 
return to the consideration of the principal postulate of the 
glacial-control theory, it should be noted that the features appealed 
to in evidence of long-enduring ocean-bottom stability are not 
directly concerned with the deep ocean floor itself, for the ocean 
floor is inaccessible to geological observation; nor do they concern 
the geological structure of islands with elevated reefs which give a 
decipherable record, for nearly all of these islands seem to have had 
elevations and subsidences during their long history. The glacial- 
control theory is chiefly concerned with atolls and submarine banks, 
the history of which is not directly decipherable; and the features 
which are taken to demand long-enduring crustal stability are, as 
already noted, the nearly level floors and the similar and moderate 
depths of atoll and barrier-reef lagoons and of submarine banks, 
although they are all covered with unconsolidated calcareous 
deposits of recent deposition and unknown thickness. 
In seeking to account for these well-substantiated submarine 
features, the glacial-control theory advances reasons for thinking 
that the nearly level lagoon deposits must be of small thickness and 
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