ANNIVERSAET ADDRESS OF THE PRESIDENT. XXXIX 



wit and common sense, aided by some training in other intellectual 

 exercises. 



Nerved by such precedents, I proceed to put my pleading before 

 you. 



And the first question with which I propose to deal is. What is it 

 to which Sir W. Thomson refers when he speaks of " geological spe- 

 culation " and " British popular geology " ? 



I find three more or less contradictory systems of geological 

 thought, each of which might fairly enough claim these appellations, 

 standing side by side in Britain. I shall call one of them Catastro- 

 PHISM, another UisriEOEMiTARiANisjvr, the third Evolutiok^ism ; and I 

 shall try briefly to sketch the characters of each, that you may say 

 whether the classification is or is not exhaustive. 



By Catastrophism I mean any form of geological speculation which, 

 in order to account for the phenomena of geology, supposes the ope- 

 ration of forces different in their nature, or immeasurably different 

 in power, from those which we at present see in action in the 

 universe. 



The Mosaic cosmogony is, in this sense, catastrophic, because it 

 assumes the operation of extra-natural power. The doctrine of 

 violent upheavals, debacles, and cataclysms in general is catastrophic, 

 so far as it assumes that these were brought about by causes which 

 have now no parallel. There was a time when catastrophism 

 might preeminently have claimed the title of " British popular geo- 

 logy;" and assuredly it has yet many adherents, and reckons among 

 its supporters some of the most honoured members of this Society. 



By Unifobmitarianism I mean preeminently the teaching of 

 Hutton and of Lyell. 



That great, though incomplete work, ' The Theory of the Earth,' 

 seems to me to be one of the most remarkable contributions to 

 geology which is recorded in the annals of the science. So far as 

 the not-living world is concerned, uniformitarianism lies there, not 

 only in germ, but in blossom and fruit. 



If one asks how it is that Hutton was led to entertain views so 

 far in advance of those prevalent in his time in some respects, while 

 in others they seem almost curiously limited, the answer appears to 

 me to be plain. 



Hutton was in advance of the geological speculation of his time, 

 because, in the first place, he had amassed a vast store of knowledge 

 of the facts of geology, gathered by personal observation in travels of 

 considerable extent, and because, in the second place, he was 

 thoroughly trained in the physical and chemical science of his day, 

 and thus possessed, as much as any one in his time could possess it, 

 the knowledge which was requisite for the just interpretation of 

 geological phenomena, and the habit of thought which fits a man for 

 scientific inquiry. 



It is to this thorough scientific training that I ascribe Hutton's 

 steady and persistent refusal to look to other causes than those now 

 in operation for the explanation of geological phenomena. 



Thus he writes : — *' I do not pretend, as he [M. de Luc] does in his 



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