162 DOWN. [ch. vm. 



well-known treatise, the- most original of all its author's 

 geological memoirs, has become one of the classics of geo- 

 logical literature. The origin of those remarkable rings of 

 coral-rock in mid-ocean has given rise to much speculation, 

 but no satisfactory solution of the problem had been pro- 

 posed. After visiting many of them, and examining also 

 coral reefs that fringe islands and continents, he offered a 

 theory which for simplicity and grandeur, strikes every 

 reader with astonishment. It is pleasant, after the lapse of 

 many years, to recall the delight with which one first read 

 the Coral Beefs, how one watched the facts being mar- 

 shalled into their places, nothing being ignored or passed 

 lightly over ; and how, step by step, one was led to the 

 grand conclusion of wide oceanic subsidence. Iso more ad- 

 mirable example of scientific method was ever given to the 

 world, and even if he had written nothing else, the treatise 

 alone would have placed Darwin in the very front of in- 

 vestigators of nature." 



It is interesting to see in the following extract from one 

 of Lyell's letters * how warmly and readily he embraced the 

 theory. The extract also gives incidentally some idea of the 

 theory itself. 



" I am very full of Darwin's new theory of Coral Islands, 

 and have urged Whewell to make him read it at our next 

 meeting. I must give wp my volcanic crater theory for 

 ever, though it cost me a pang at first, for it accounted for 

 so much, the annular form, the central lagoon, the sudden 

 rising of an isolated mountain in a deep sea ; all went so 

 well with the notion of submerged, crateriform, and conical 

 volcanoes, . . . and then the fact that in the South Pacific 

 we had scarcely any rocks in the regions of coral islands, 

 save two kinds, coral limestone and volcanic ! Yet in spite 

 of all this, the whole theory is knocked on the head, and the 

 annular shape and central lagoon have nothing to do with 

 volcanoes, nor even with a crateriform bottom. Perhaps 

 Darwin told you when at the Cape what he considers the 

 true cause? Let any mountain be submerged gradually, 

 and coral grow in the sea in which it is sinking, and there 

 will be a ring of coral, and finally only a lagoon in the cen- 

 tre. . . . Coral islands are the last efforts of drowning con- 

 tinents to lift their heads above water. Eegions of elevation 



* To Sir John Herscliel, May 24, 1837. Life of Sir Charles Zyell, vol. ii, 

 p. 12. 



