Charles Darwin, Geologist
- Sandra Herbert
In 1836, Charles Darwin returned to England after his five-year voyage on HMS Beagle. He soon became a closet evolutionist, working on his biological theory of evolution before publishing On the Origin of Species in 1859. These bare facts are not incorrect, but they are seriously incomplete. Two years after his return, reflecting on his life so far, he described himself as “I the geologist...” This was not an isolated remark — it expressed his chosen identity. Indeed, it was as a competent geologist that Darwin first came to the attention of the scientific community and made his name as a promising young ‘man of science’.
His main interests gradually shifted sideways from geology into zoology and botany, but it is deeply misleading to read his career as if there was an inevitability about the move. This has been well known to Darwin specialists, but Sandra Herbert's Charles Darwin, Geologist is the first full-length treatment of his geological research, describing and analysing the work in its own right as well as in its role as a foundation for his later biological work.
Herbert's approach is not strictly biographical; some background knowledge of Darwin's life — best gleaned from Janet Browne's superbly readable two-volume Charles Darwin (Jonathan Cape, 2003) — is, in effect, taken for granted. Herbert treats Darwin's geological work as a series of specific topics, with a chronological analysis of each. Although she covers in outline almost his entire career, she focuses on Darwin's Beagle years, his fruitful few years in London, and the first years of his long life at Downe in Kent — in other words, on the 1830s and early 1840s.
As a highly respected member of the scholarly ‘Darwin industry’, she has an enviably thorough knowledge of the vast Darwin manuscript archive. She makes full use of the revealing details of Darwin's famous scientific notebooks and his voluminous correspondence, which greatly deepen our understanding of his published work.
Herbert rightly emphasizes that the geology to which the young Darwin contributed was already a well-established science. He had excellent informal training from Adam Sedgwick and John Henslow at the University of Cambridge, support from a substantial scientific library on board the Beagle, and inspiration from Charles Lyell's newly published Principles of Geology. Above all, he had the stimulus of intelligent discussion at the Geological Society in London after his return.
After spreading his attention widely at first, he concentrated increasingly on one of geology's focal problems at the time: that of crustal elevation and subsidence. This underlay his interest in the effects of the great earthquake he witnessed in Chile, as well as his fieldwork in the high Andes. It led him to out-Lyell Lyell — giving an even better explanation in terms of observable processes — with his innovative theory of coral reefs, sketched in outline before he ever saw one, in which corals functioned simply as markers of crustal movement.
With sublime confidence, he anticipated that the “geology of whole world will turn out simple”. His ‘theory of the Earth’, like Lyell's, was one that envisaged the ceaseless movement of crustal plates, not horizontally as in modern plate-tectonic theory, but vertically. However, after his return to Britain he cited the famous Parallel Roads of Glen Roy in Scotland in support of his theory, only to be upstaged by the Swiss naturalist Louis Agassiz's glacial theory, which was a far better explanation for the puzzling terraces. This was a critical challenge to ‘simplicity’ in the light of which Darwin eventually conceded that his own effort had been a “gigantic blunder”.
Interspersed with Herbert's valuable analyses of Darwin's geological fieldwork and theorizing are chapters on other topics. In line with current trends in the historiography of other sciences, she describes in fascinating detail the practical aspects of Darwin's geology: his hammer and other instruments, his methods for collecting specimens and making notes, and so on. She also discusses the Romanticism of the travel narratives that he took as his literary models, and the contemporary debates in England about geology and Genesis. And, perhaps of greatest interest to other Darwin scholars and to biologists, she analyses with care the ways in which his geology generated the problems to which his eventual theory of the origin of new species was designed to be the solution.
I have only two reservations about this fine volume. The first is that Herbert tends to underestimate the extent to which Darwin was developing lines of research already being explored by other geologists — not only his hero Lyell but also those who were critical of Lyell's theories. Second, like Darwin himself — who was only fluent in English — she does not adequately emphasize the thoroughly international character of the geological world during the most creative period of his life. Nonetheless, this is a highly important contribution, not just to Darwin studies but also to the sadly neglected field of the history of geology itself.