2 Anniversary Address of the 



to the most sceptical a far less visionary and extravagant 

 hypothesis than w^hen I first declared my belief in its truth. 

 As, however, there are not a few original observers, whose 

 opinion I respect, who are still opposed to this doctrine, 1 

 cannot I believe do better on the present occasion than take 

 a brief view of the bearing of some leading discoveries of 

 modern date on this much- con trover ted question. I adopt 

 this course the more willingly, because a perusal of the 

 memoirs read before the Society during the past session, and 

 the contemporary publications of other scientific bodies and 

 authors in Europe and America, has convinced me that they 

 are so varied and so overwhelming by their number and im- 

 poi'tance, as to make it impossible, within the limits of this 

 anniversary Address, to give an analysis of the contents of 

 each, still less to add criticisms and comments of my own. 

 But in order to keep myself still further within due bounds, 

 I shall not enter at present the field of palseontology, re- 

 serving for a future opportunity a comparison of the organic 

 creation, in ancient and modern times, and the question 

 whether the fluctuations of the living inhabitants of the 

 globe have been regulated formerly by the same laws as now. 

 Among the points of geological interest relating exclu- 

 sively to the inanimate world, none have given rise to a 

 greater difference of opinion than the various causes sug- 

 gested to account for the position of stratified and un strati- 

 fied rocks in mountain chains. They are usually referred 

 to the development of mechanical and volcanic forces of a 

 paroxysmal character ; but geologists who favour these 

 views are by no means agreed whether the causes thus cap- 

 able of modifying the earth's crust, were all of them in the 

 beginning in a state of the highest intensity, and afterwards 

 declined in energy ; or whether they have been exerted again 

 and again during short intervals of violent convulsion, fol- 

 lowed by long periods of repose. On these, and questions 

 of a kindred nature, I shall proceed to offer some observa- 

 tions, well aware that I shall advocate opinions wliich I have 

 long cherished, and on which I can scarcely fail to have a 

 strong bias ; but reminding you at the same time, that they 

 who defend conclusions opposed to mine, have equal reason 



