Charles Lyell

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Charles Lyell : biography

14 November 1797 – 22 February 1875

Glaciers

In Principles of Geology (first edition, vol. 3, Ch. 2, 1833) Lyell proposed that icebergs could be the means of transport for erratics. During periods of global warming, ice breaks off the poles and floats across submerged continents, carrying debris with it, he conjectured. When the iceberg melts, it rains down sediments upon the land. Because this theory could account for the presence of diluvium, the word drift became the preferred term for the loose, unsorted material, today called till. Furthermore, Lyell believed that the accumulation of fine angular particles covering much of the world (today called loess) was a deposit settled from mountain flood water. Today some of Lyell’s mechanisms for geologic processes have been disproven, though many have stood the test of time. His observational methods and general analytical framework remain in use today as foundational principles in geology.

Evolution

Lyell first received a copy of one of Lamarck’s books from Mantell in 1827, when he was on circuit. He thanked Mantell in a letter which includes this enthusiastic passage:

"I devoured Lamark… his theories delighted me… I am glad that he has been courageous enough and logical enough to admit that his argument, if pushed as far as it must go, if worth anything, would prove that men may have come from the Ourang-Outang. But after all, what changes species may really undergo!… That the Earth is quite as old as he supposes, has long been my creed…" Lyell K. 1881. The life and letters of Sir Charles Lyell. 2 vols, London. vol. 1 p. 168

In the second volume of the first edition of Principles Lyell explicitly rejected the mechanism of Lamark on the transmutation of species, and was doubtful whether species were mutable.Lyell C. 1830–33. The principles of geology. Murray, London. vol. 2, Chapter 2. However, privately, in letters, he was more open to the possibility of evolution:

"If I had stated… the possibility of the introduction or origination of fresh species being a natural, in contradistinction to a miraculous process, I should have raised a host of prejudices against me, which are unfortunately opposed at every step to any philosopher who attempts to address the public on these mysterious subjects".Lyell to William Whewell, March 7, 1837. In Lyell K. 1881. The life and letters of Sir Charles Lyell. 2 vols, London. vol. 2 p. 5

This letter makes it clear that his equivocation on evolution was, at least at first, a deliberate tactic. As a result of his letters and, no doubt, personal conversations, Huxley and Haeckel were convinced that, at the time he wrote Principles, he believed new species had arisen by natural methods. Both Whewell and Sedgwick wrote worried letters to him about this.Judd J.W. 1910. The coming of evolution. Cambridge. Chapter 8, pp. 83–86.

Later, Darwin became a close personal friend, and Lyell was one of the first scientists to support On the Origin of Species, though he did not subscribe to all its contents. Lyell was also a friend of Darwin’s closest colleagues, Hooker and Huxley, but unlike them he struggled to square his religious beliefs with evolution. This inner struggle has been much commented on. He had particular difficulty in believing in natural selection as the main motive force in evolution.Bowler P.J. 2003. . 3rd ed, University of California Press. ISBN 0-520-23693-9 pp. 129–134, 215Mayr E. 1982. . Harvard University Press. ISBN 0-674-36446-5 (esp pp. 375–381, 404–408).

Lyell and Hooker were instrumental in arranging the peaceful co-publication of the theory of natural selection by Darwin and Alfred Russel Wallace in 1858: each had arrived at the theory independently. Lyell’s data on stratigraphy were important because Darwin thought that populations of an organism changed slowly, requiring "geologic time".

Although Lyell did not publicly accept evolution (descent with modification) at the time of writing the Principles,Lyell C. 1830–33. The principles of geology. Murray, London. vol. 2, pp. 20–21. after the Darwin–Wallace papers and the Origin Lyell wrote in his notebook: