iy8 HUTTONIAN THEORY 



comparatively feeble action as is now witnessed by 

 man could alone be recognised in the evidence from 

 which geological history must be compiled. Well do 

 I remember in my own boyhood what a cardinal 

 article of faith this prepossession had become. We 

 were taught by our great and honoured master, Lyell, 

 to believe implicitly in gentle and uniform operations, 

 extended over indefinite periods of time, though pos- 

 sibly some, with the zeal of partisans, carried this 

 belief to an extreme which Lyell himself did not 

 approve. The most stupendous marks of terrestrial 

 disturbance, such as the structure of great mountain 

 chains, were deemed to be more satisfactorily accounted 

 for by slow movements prolonged through indefinite 

 ages than by any sudden convulsion. 



What the more extreme members of the uniformi- 

 tarian school failed to perceive was the absence of 

 all evidence that terrestrial catastrophes even on a 

 colossal scale might not be a part of the present 

 economy of this globe. Such occurrences might 

 never seriously affect the whole earth at one time, 

 and might return at such wide intervals that no 

 example of them has yet been chronicled by man. 

 But that they have occurred again and again, and 

 even within comparatively recent geological times, 

 hardly admits of serious doubt. How far at different 

 epochs and in various degrees they may have included 

 the operation of cosmical influences lying wholly out- 

 side the planet, and how far they have resulted from 

 movements within the body of the planet itself, must 

 remain for further inquiry. Yet the admission that 

 they have played a part in geological history may be 



