Red Sea.
REEFS, irregular in shallow seas. Rising to the surface in some lagoons and all submerged in others. Their distribution. Their absence from some coasts.
Revilla-gigedo.
RING-FORMED REEFS of the Maldiva atolls, and theory of.
Rodriguez.
Rosario.
Rose island.
Rotches.
Rotoumah.
Roug.