The third of his geological books, 'Geological Observations on South America,' may be mentioned here, although it was not published until 1846. "In this work the author embodied all the materials collected by him for the illustration of South American Geology, save some which have been published elsewhere. One of the most important features of the book was the evidence which it brought forward to prove the slow interrupted elevation of the South American Continent during a recent geological period." (Geikie, loc.英文原著 · 《The Life and Letters-1》
Opens first note-book of 'Origin of Species.' Meets Lyell and Robert Brown. Marries. Works on his 'Coral Reefs.' Reads papers before Geological Society. Acts as secretary of the Geological Society. Residence at Down. His absorption in science. His publications. 'Geological Observations' published.英文原著 · 《The Life and Letters-2》
"It is the completion of a short paper read before the Geological Society more than forty years ago, and has revived old geological thoughts...As far as I can judge it will be a curious little book."英文原著 · 《Darwin and Modern Science》
It is clear that, as time went on, Darwin became more and more absorbed in his geological work. One very significant fact was that the once ardent sportsman, when he found that shooting the necessary game and zoological specimens interfered with his work with the hammer, gave up his gun to his servant. ("L.L." I. page 63.) There is clear evidence that Darwin gradually became aware how futile were his attempts to add to zoological knowledge by dissection and drawing, while he felt ever increasing satisfaction with his geological work.英文原著 · 《Darwin and Modern Science》
The third and most active portion of Darwin's career as a geologist was the period which followed his return to England at the end of 1836. His immediate admission to the Geological Society, at the beginning of 1837, coincided with an important crisis in the history of geological science.英文原著 · 《Darwin and Modern Science》
The completion of the "Geology of the 'Beagle'" and the preparation of a revised narrative of the voyage mark the termination of that period of fifteen years of Darwin's life during which geological studies were his principal occupation. Henceforth, though his interest in geological questions remained ever keen, biological problems engaged more and more of his attention to the partial exclusion of geology.英文原著 · 《Darwin and Modern Science》