LYELL 249 



Of Buckland's pupils, the greatest was Lyell, whose 

 fame, indeed, overshadows his master's. Hutton had pro- 

 pounded the theory of the efficacy of modern causes, 

 Playfair had illustrated it, and Lyell spent his life in 

 defending and elaborating it. In consequence of his 

 success in this work, it is far more often associated with 

 Lyell's name, who was its foster-parent, than with 

 Hutton's, who was its true originator. 



We have already /alluded to this doctrine. It is that 

 the only method by which an explanation of the past can 

 be obtained is by a careful study of the processes of the 

 present, or, as it is often epigrammatically expressed, 

 " Geology finds in the processes of the present a key to 

 unlock the past." It must be confessed at the outset 

 that it is difficult to see where else she would find it ; not 

 in the future, of which we know nothing, and scarcely in 

 the past itself, whose problems are to be explained. 

 Epigrams are frequently only a neat way of obscuring 

 a truth; in this case the fact would appear to be 

 that ' most of the older observers, when they en- 

 countered interruptions in the succession of strata, 

 were accustomed to explain them by interruptions 

 in the orderly progress of nature, by sudden and 

 violent changes, which were spoken of as catastrophes. 

 Hutton and Lyell were able to offer explanations of these 

 without the invocation of catastrophes. They certainly 

 introduced the scientific method into cases which had 

 previously been treated by a too free use of the imagina- 

 tion, and thus their doctrine, the doctrine of uniformity, 

 has dominated geologic thought for the past sixty years, 

 and will probably continue to do so for many years to 

 come. The teachings of Hutton and Lyell have, how- 

 ever, another side ; they assume not only that existing 

 causes have acted in the past as in the present, but at 

 the same uniform rate : this was the natural result of 



