a''a

Updated: June 4, 2025

SECTION OF CORAL-REEF. A'A', Outer edges of the barrier-reef at the level of the sea, with islets on it. B'B', The shores of the included island. CC, The lagoon-channel. A''A'', Outer edges of the reef, now converted into an atoll. C', The lagoon of the new atoll.

Charles Darwin - The Voyage of the Beagle