David, Mrs Edgeworth, Funafuti or Three Months On A Coral Atoll: an unscientific account of a scientific expedition, London: John Murray, 1899 At the time these results were regarded as inconclusive and it was not until the 1950s when, prior to carrying out nuclear bomb tests on Eniwetok, deep exploratory drilling through 4200 feet of coral to the underlying basalt finally vindicated Darwin's theory.