XI.] GEOLOGICAL REFORM. "220 



reversal of the sentence to that higher court of educated 

 scientific opinion to which we arc all amenable. 



As your attorney-general for the time being, I thought 

 I could not do better than get up the case with a view 

 of advising you. It is true that the charges brought 

 forward by the other side involve the consideration of 

 matters quite foreign to the pursuits with which I am 

 ordinarily occupied ; but, in that respect, I am only in 

 the position which is, nine times out of ten, occupied by 

 counsel, who nevertheless contrive to gain their causes, 

 mainly by force of mother- 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 speculation " and " British popular 

 geology ;j ? 



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 Catastpophism, another Uni- 

 formitailianism, the third Evolutionism ; and I shall 

 try briefly to sketeh 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 operation 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 cata- 

 clysms in general, is catastrophic, so far as it assumes 

 that these were brought about by causes which have 

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