Wharton's and Darwin's Theories of Coral Reefs (Report‪)‬

There is a passage in Gardiner's review (1) of my book on coral reefs (2) which puzzles me. He there wrote: "It may be that Wharton's views ... are 'against the consensus of geological opinion,' but I have failed to find any evidence cited against Wharton's idea of an island being cut down by the waves and currents to a flat bank 30-40 fathoms deep." Taken with the context, this can only mean that Gardiner regards Wharton's theory of atolls as still tenable; for if it be agreed that the foundations of atolls have actually been prepared by cutting down volcanic islands to flat submarine banks, as Wharton believed, the later upgrowth of the reefs around the bank margins to form atolls is acceptable enough. The puzzling part of the above quotation is therefore that Gardiner appears to "have failed to find any evidence" cogently cited against Wharton's theory; for, as I see the case, the counterevidence is not only manifest and abundant but also unquestionable and convincing. In order to make this clear, let us look somewhat closely at the theory which Wharton proposed. That experienced hydrographer was impressed, some thirty-five years ago, with the flatness of atoll-lagoon floors, in which he could not find the "deeply concave surface" of Darwin's text (1842, 93); but Wharton there misunderstood Darwin's meaning, for, although the originator of the subsidence theory of coral reefs also used other similar phrases, such as "saucer-shaped hollow" (28) and "bason-like form" (92) in connection with atoll lagoons, he elsewhere stated explicitly that "the greater part of the bottom in most lagoons is formed of sediment; large spaces have exactly the same depth" (20), thus showing that concavity is subordinate to flatness, and he very properly adduced the processes of aqueous deposition to account for the flatness with which lagoon-floor sediment are spread out.