Labels:earth | sky OCR: Island Sections with Barrier -Reefs CNot scale) 3032 440 ft.B 1248 800 ft. 1 Vanikoro. Gambier Islands. 3. Maurua. the horizontal shading shows the barrier-reefs and lagoon. -channels. The inclined shading above the level of the sea [AA) shows the actual form of the land; the inclined shading below this line, shows its probable prolongation under water DARWIN: VOYAGE THE Beagle