338 Darwin and Geology 
It is the first of these inquiries which specially interests the 
geologist ; though geology undoubtedly played a part—and by no 
means an insignificant part—in respect to the second inquiry. 
When, indeed, the history comes to be written of that great 
revolution of thought in the nineteenth century, by which the 
doctrine of evolution, from being the dream of poets and visionaries, 
gradually grew to be the accepted creed of naturalists, the para- 
mount influence exerted by the infant science of geology—and 
especially that resulting from the publication of Lyell’s epoch- 
making work, the Principles of Geology—cannot fail to be regarded 
as one of the leading factors. Herbert Spencer in his Autobiography 
bears testimony to the effect produced on his mind by the recently 
published Principles, when, at the age of twenty, he had already 
begun to speculate on the subject of evolution’; and Alfred Russel 
Wallace is scarcely less emphatic concerning the part played by 
Lyell’s teaching in his scientific education®. Huxley wrote in 1887 
“T owe more than I can tell to the careful study of the Principles of 
Geology in my young days*” As for Charles Darwin, he never 
tired—either in his published writings, his private correspondence 
or his most intimate conversations—of ascribing the awakening of 
his enthusiasm and the direction of his energies towards the 
elucidation of the problem of development to the Principles of 
Geology and the personal influence of its author. Huxley has well 
expressed what the author of the Origin of Species so constantly 
insisted upon, in the statements “Darwin’s greatest work is the 
outcome of the unflinching application to Biology of the leading 
idea and the method applied in the Principles to Geology*,” and 
“Lyell, for others, as for myself, was the chief agent in smoothing 
the road for Darwin®.” 
We propose therefore to consider, first, what Darwin owed to 
geology and its cultivators, and in the second place how he was able 
in the end so fully to pay a great debt which he never failed to 
acknowledge. Thanks to the invaluable materials contained in the 
Life and Letters of Charles Darwin (3 vols.) published by Mr Francis 
Darwin in 1887; and to More Letters of Charles Darwin (2 vols.) 
issued by the same author, in conjunction with Professor A. C. 
Seward, in 1903, we are permitted to follow the various movements 
1 Herbert Spencer’s Autobiography, London, 1904, Vol. 1. pp. 175—177. 
2 See My Life; a record of Events and Opinions, London, 1905, Vol. 1. p. 355, eto. 
Also his review of Lyell’s Principles in Quarterly Review (Vol. 126), 1869, pp. 359—394, 
See also The Darwin-Wallace Celebration by the Linnean Society (1909), p. 118. 
3 “Science and Pseudo Science ;” Collected Essays, London, 1902, Vol, v. p. 101, 
4 Proc. Roy. Soc. Vol. xurv. (1888), p. viii. ; Collected Essays, 11. p. 268, 1902. 
5 Life and Letters of Charles Darwin, u. p. 190. 
