vi] OF EVOLUTION 57 



less than one fourth of the period of his active life 

 was spent in travel 45 . 



The joint excursion of Lyell and Murchison to 

 the Auvergne was destined to have great influence 

 on the minds of these pioneers in geological research ; 

 both became satisfied from their studies that, with 

 respect to the excavation of the valleys of the 

 country, Scrope's conclusions were irresistible ; and 

 in a joint memoir this position was stoutly main- 

 tained by them. 



It is interesting to notice the impression made by 

 these two great geologists on one another during this 

 joint expedition. 



Murchison wrote that he had seen in Lyell 'the 

 most scrupulous and minute fidelity of observation 

 combined with close application in the closet and 

 ceaseless exertion in the field 46 .' 



But I recollect that Lyell once told me how 

 difficult Murchison found it to restrain himself from 

 impatience, when his companion's attention was 

 drawn aside by his entomological ardour. In an 

 early letter, indeed, we find that Murchison often 

 expressed a wish that Lyell's sisters had been with 

 them to attend to the insect-collecting and thus leave 

 Lyell free for geological work 47 . 



On the other hand, Lyell informed me that 

 Murchison had rendered him a great service in 

 showing how much a geologist could accomplish by 



