Charles Darwin and the theory of natural selection / by Edward B. Poulton.

  • Poulton, Edward Bagnall, Sir, 1856-1943.
Date:
1896
Catalogue details

Licence: Public Domain Mark

Credit: Charles Darwin and the theory of natural selection / by Edward B. Poulton. Source: Wellcome Collection.

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    ON CORAL REEFS. ЯЯ edition in 1874). This луогк contains an account of Darwin's луеП-кполуп theory upon the origin of the various coral formations—fringing reefs, barrier reefs, and atolls—by the upward growth of the reef keep¬ ing pace лvith the gradual sinking of the island upon Avhich it is based, so that the living corals always remain at the surface under the most favourable conditions, луЬ11е beneath them is an ever-thickening reef formed of dead coral, until at length, by con¬ tinuing this process, the climax is reached in the atoll, in which the original island has altogether disappeared beneath the surface of a central lagoon enclosed in a ring formed by the living edge of the reef This theory, after being accepted for many years, has recently been disputed, chiefly as the result of the observations made on the Challenger expedition. It is contended by Dr. John Murray that it is not necessary to call in subsidence to explain any of the characteristic features of barrier reefs or atolls, and that all these features would exist alike in areas of slow elevation, of rest, or of slow subsidence {Nature, August 12th, 1880, p. 337). It cannot be said that this controversy is yet settled, or that the supporters of either theory have proved that the other does not hold—at any rate, in certain cases. Among his geological papers written at this time was one describing the glacial phenomena observed during a tour in North Wales. This paper {Philo¬ sophical Magazine, 1842, p. 352) is placed by Sir