XXXU PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



fifty, on the 27th of September, 1849, deeply regretted by all those 

 who knew him'^. 



Gentlemen, — It is now my duty, in accordance with the usual 

 custom of my predecessors in office, to say something of the scientific 

 labours of geologists during the past session. It is nearly twenty 

 years since I announced, in the first edition of my ' Principles of 

 Geology,' the conviction at which I had then arrived, after devoting 

 some time to observation in the field, and to the study of the works of 

 earlier \^Titers, that the existing causes of change in the animate and 

 inanimate world might be similar, not only in kind, but in degree, to 

 those which have prevailed during many successive modifications of 

 the earth's crust. I attempted to adapt the views which Hutton and 

 Playfair had first promulgated, to a more advanced state of our science, 

 and to extend their appUcation, by showing, that should the same 

 causes continue to act with unabated energy, for indefinite periods of 

 the future, they must bring about revolutions not inferior in magni- 

 tude to those recorded in the monuments of past ages. After an in- 

 terval of twenty years, during which Geology has been enriched by a 

 vast accession of new facts, and when so many powerful minds, in 

 every civilized country, have brought their intellectual energies to bear 

 on the philosophy of our science, I may I think afiirm that the idea of 

 comparing the modern agents of change with those of remote epochs, 

 as not inferior in power and intensity, appears even to the most scep- 

 tical a far less visionary and extravagant hypothesis than when I first 

 declared my belief in its truth. As, however, there are not a few ori- 

 ginal observers, whose opinion I respect, who are stiU opposed to this 

 doctrine, I 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-controverted 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 cominced me 

 that they are so varied and so overwhelming by their number and 

 importance, as to make it impossible, within the limits of this anni- 

 versary Address, to give an analysis of the contents of each, still less 



* A fuHer account of Mr. Dixon's labours will be found in the 'Medical Times ' 

 for Dec. 8, 1849. of which notice I have largely availed myself. 



