Ivii 



power, consumed niucli of his time ; but he was now in the prime of 

 his intellectual energy ; financial cares, moreover, though still present, 

 were gradually lessening ; and during the next decennium he found 

 opportunity to do some of the best of his purely scientific work. 



Yet once more the fossils " were upon him," and indeed this 

 decennium of his life was to a considerable extent a geological one. 

 In 1862, at the close of his term of office as Secretary to the Geolo- 

 gical Society, he was called upon, in the absence of the President, 

 Mr. Leonard Horner, to deliver the Presidential Address, and in this 

 he shattered an accepted doctrine of the geologists of the day, that a 

 similar succession of organic remains in two distinct regions denoted 

 synchronism of formation in the strata containing them. He intro- 

 duced the word " homotaxis " to denote what alone was really shown 

 by the facts, namely, that in each region the forms of life had fol- 

 lowed each other in the same general order. It is worthy of note that 

 in this same address, though at the time in the very flush of advocacy 

 before the people of the doctrines laid down in the ' Origin of Species ' 

 as a reasonable hypothesis of a mode of evolution, he showed his 

 anxiety that his scientific brethren should distinguish between a 

 hypothesis for which there was much to be said, and a clear positive 

 demonstration by the evidence of facts. Knowing his audience, he 

 did not once allude to Darwin ; he did not even think it necessary to 

 speak of the imperfection of the geological record ; aware that the 

 younger geologists were likely to be carried beyond the evidence by 

 the fascination of the general idea, he used his critical power to show 

 that so far as the then knowledge went there was no case clearly 

 made out by any fossil remains of any one form being progressively 

 modified into others. But his attitude in this was an attitude of 

 judicial caution only. In the address which, as President of the 

 same Society, he had to give in 1868, dwelling on the catastrophic 

 and uniform itari an schools of geological thought, he showed in a 

 most powerful mi nner how the doctrine of evolution, taking in all 

 that was good of each of the other schools, was destined to be the 

 guide of geologists in the future. Further, in the Presidential 

 Address which again he had to give in 1872, he pointed out how 

 much even ten years hid added to palseontological knowledge; so 

 that now at least it mi^ht be said, in the case of the higher verte- 

 brates, evolution had been proved as a historical fact. Since that 

 date evidence has rolled in fast, and in his latest utterances,' in the 

 year before his death, he was able to p< int to the plain teaching of 

 palaeontological records as affording clear and absolute proof of evolu- 

 tion having taken place, a proof the validity of which could never be 

 shaken by the fate which might in the future await the reasonable 

 hypothesis of Mr. Darwin as to how evolution had taken place. 



Though he was at this time prominent among geologists, and they 



