CHARLES LYELL'S PRINCIPLES OF GEOLOGY IN ITS RELATION TO THE SPECIES QUESTION

Some books are like arrows: lean, logical, directed to one target. Others are more diffuse, more protean. A few books combine these characteristics. Charles Lyell’s three volume Principles of Geology (1830-1833) is one of these. On the one hand it is targeted, as indicated in its famous subtitle “An attempt to explain the former changes of the Earth’s surface, by reference to causes now in operation.” On the other hand, compared to other books in geology of its period, it was remarkably broad in its range. Volume 2 of the first edition of the Principles was published in 1832. In it Lyell addressed what he termed the “Changes of the Organic World now in progress.” Under this rubric Lyell would consider the nature of species and of their creation and extinction. He thus posed what I am calling the “species question.” Lyell would also state the theory of transmutation posed by Jean Baptiste de Lamarck, and then argue against that theory. Although it was surely not Lyell’s intention, the effect of his treatment of species in the Principles of Geology was to pose the species question in a way in which it could be solved by an equally brilliant reader of his book: Charles Darwin. The purpose of my paper is to explore the relationship between writer and reader, between Lyell and Darwin (and, later, between Darwin and Lyell), over the course of the ensuing 30 years. I will use both their published writings and their manuscripts. Of the latter Darwin’s notebooks from the 1830s and Lyell’s notebooks from the 1850s are of special importance. I will also consider Lyell’s role in paving the way for Darwin’s evolutionary ideas in North America.