Abstract
When HMS Beagle made its first landfall in January 1832, the twenty-two-year-old Charles Darwin set about taking detailed notes on geology. He was soon planning a volume on the geological structure of the places visited, and letters to his sisters confirm that he identified himself as a ‘geologist’. For a young gentleman of his class and income, this was a remarkable thing to do. Darwin's conversion to evolution by selection has been examined so intensively that it is easy to forget that the most extraordinary decision he ever made was to devote his life to the study of the natural world by becoming a geologist. It is only slightly less astonishing that he should have decided to align his work with Charles Lyell's controversial programme of geological reform, which had almost no followers in England