CONTENTS. V 



— Great Crab— Stinging Corals— Coral-eating Fish— Coral For- 

 mations—Lagoon Islands or Atolls— Depth at which reef-build- 

 ing Corals can live — Vast Areas interspersed with low Coral 

 Islands — Subsidence of their Foundations — Barrier Reefs — 

 Fringing Reefs— Conversion of Fringing Reefs into Barrier 

 Reefs and into Atolls — Evidence of Changes in Level — Breach- 

 es in Barrier Reefs — Maldiva Atolls ; their peculiar Structure— 

 • Dead and submerged Reefs — Areas of Subsidence and Eleva- 

 tion—Distribution of Volcanoes— Subsidence Slow, and vast 

 in Amount Page 243 



CHAPTER IX. 



Mauritius, beautiful Appearance of— Great crateriform Ring of 

 Mountains— Hindoos— St. Helena— History of the Changes in 

 the Vegetation — Cause of the Extinction of Land-shells — As- 

 cension — Variation in the imported Rats — Volcanic Bombs — 

 Beds of Infusoria— Bahia— Brazil— Splendour of tropical Scen- 

 ery — Pernambuco — Singular Reef— Slavery — Return to Eng- 

 land — Retrospect on our Voyage 281 



Indkx .... 313 



