THE STRUCTURE AND DISTRIBUTION OF CORAL REEFS
CHAPTER I.—ATOLLS OR LAGOON-ISLANDS
CHAPTER III.—FRINGING OR SHORE-REEFS
CHAPTER IV.—ON THE DISTRIBUTION AND GROWTH OFCORAL-REEFS
CHAPTER V.—THEORY OF THE FORMATION OF THE DIFFERENTCLASSES OF CORAL-REEFS
CHAPTER VI.—ON THE DISTRIBUTION OF CORAL-REEFS WITHREFERENCE TO THE THEORY OF THEIR FORMATION
CHAPTER I.—ATOLLS OR LAGOON-ISLANDS
SECTION I.—DESCRIPTION OF KEELING ATOLL. Corals on the outermargin.—Zone of Nulliporæ.—Exteriorreef.—Islets.—Coral-conglomerate.—Lagoon.—Calcareoussediment.—Scari and Holuthuriæ subsisting on corals.—Changes in thecondition of the reefs and islets.—Probable subsidence of theatoll.—Future state of the lagoon.
SECTION II.—GENERAL DESCRIPTION OF ATOLLS. General form and size ofatolls, their reefs and islets.—External slope.— Zone ofNulliporæ.—Conglomerate.—Depth oflagoons.—Sediment.—Reefs submerged wholly or inpart.—Breaches in the reef.—Ledge-formed shores round certainlagoons.—Conversion of lagoons into land.
SECTION III.—ATOLLS OF THE MALDIVA ARCHIPELAGO—GREAT CHAGOS BANK.Maldiva Archipelago.—Ring-formed reefs, marginal and central.—Greatdepths in the lagoons of the southern atolls.—Reefs in the lagoons allrising to the surface.—Position of islets and breaches in the reefs, withrespect to the prevalent winds and action of the waves.—Destruction ofislets.—Connection in the position and submarine foundation of distinctatolls.—The apparent disseverment of large atolls.—The Great ChagosBank.—Its submerged condition and extraordinary structure.
CHAPTER II.—BARRIER REEFS
Closely resemble in general form and structure atoll-reefs.—Width anddepth of the lagoon-channels.—Breaches through the reef in front ofvalleys, and generally on the leeward side.—Checks to the filling up ofthe lagoon-channels.—Size and constitution of the encircledislands.— Number of islands within the same reef.—Barrier-reefs ofNew Caledonia and Australia.—Position of the reef relative to the slopeof the adjoining land.—Probable great thickness ofbarrier-reefs.
CHAPTER III.—FRINGING OR SHORE-REEFS
Reefs of Mauritius.—Shallow channel within the reef.—Its slowfilling up.—Currents of water formed within it.—Upraisedreefs.—Narrow fringing-reefs in deep seas.—Reefs on the coast of E.Africa and of Brazil.—Fringing-reefs in very shallow seas, round banks ofsediment and on worn-down islands.—Fringing-reefs affected by currents ofthe sea. —Coral coating the bottom of the sea, but not formingreefs.
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