The Structure and Distribution of Coral Reefs: Being the First Part of the Geology of the Voyage of the Beagle, Under the Command of Capt. Fitzroy, R.N. During the Years 1832 to 1836

The Structure And Distribution Of Coral Reefs: Being The First Part Of The Geology Of The Voyage Of The Beagle, Under The Command Of Capt. Fitzroy, R.N. During The Years 1832 To 1836 by Charles Darwin. This treatise describes coral reef types—lagoon-islands (atolls), barrier reefs, and fringing reefs—and proposes a subsidence-based theory for their origin: reefs grow upward as their bases gradually sink, forming circular atolls and surrounding barriers. Darwin draws on extensive observations from the Beagle voyage, including Keeling Atoll, the Maldive atolls, the Great Chagos Bank, and other archipelagos. He analyzes reef margins, lagoons, sediment, currents, and the polypifers responsible for reef-building, examining how depth limits, wave action, and sediment affect growth. The work also discusses the distribution of reefs worldwide, the rate of reef growth, and the implications for geology and the history of land–sea interaction, and includes plates and an Appendix detailing reefs and islands.