CORAL REEFS AND SUBMARINE BANKS 300 
Neither the break of the exterior slope nor the level of the lagoon 
floor of existing reefs is, as far as I can make out, the record of a 
former lower sea-level: both appear to have been brought into 
relation with present sea-level by processes now acting. It cer- 
tainly seems as reasonable to explain the exterior profile of coral 
reefs in this way as to explain “the break of slope on the [conti- 
nental| shelves . . . . near the 40-fathom line”’ as a result of wave 
and current action at the present stand of the ocean surface, and 
therefore since the present stand was assumed. 
[To be continued | 
