5 g AUTOBIOGRAPHY. 



hard as I possibly could, than during any other equal length 

 of time in my life. This was owing to frequently recurring 

 unwellness, and to one long and serious illness. The greater 

 part of my time, when I could do anything, was devoted to 

 my work on ' Coral Reefs,' which I had begun before my 

 marriage, and of which the last proof-sheet was corrected on 

 May 6th, 1842. This book, though a small one, cost me 

 twenty months of hard work, as I had to read every work on 

 the islands of the Pacific and to consult many charts. It was 

 thought highly of by scientific men, and the theory therein 

 given is, I think, now well established. 



No other work of mine was begun in so deductive a spirit 

 as this, for the whole theory was thought out on the west 

 coast of South America, before I had seen a true coral reef. 

 I had therefore only to verify and extend my views by a care- 

 ful examination of living reefs. But it should be observed 

 that I had during the two previous years been incessantly at- 

 tending to the effects on the shores of South America of the 

 intermittent elevation of the land, together with denudation 

 and the deposition of sediment. This necessarily led me to 

 reflect much on the effects of subsidence, and it was easy to 

 replace in imagination the continued deposition of sediment 

 by the upward growth of- corals. To do this was to form 

 my theory of the formation of barrier-reefs and atolls. 



Besides my work on coral-reefs, during my residence in 

 London, I read before the Geological Society papers on the 

 Erratic Boulders of South America,* on Earthquakes,! and 

 on the Formation by the Agency of Earth-worms of Mould.]! 

 I also continued to superintend the publication of the ' Zoology 

 of the Voyage of the Beagle' Nor did I ever intermit col- 

 lecting facts bearing on the origin of species ; and I could 

 sometimes do this when I could do nothing else from illness. 



In the summer of 1842 I was stronger than I had been for 

 some time, and took a little tour by myself in North Wales, 



* ' Geolog. Soc. Proc.' iii. 1842. f ' Geolog. Trans.' v. 1840. 



\ ' Geolog. Soc. Proc.' ii. 1838. 



