Geological Society of London. 187 



voltaic agency had some influence in such cases as tbosc described by 

 Mr Fox ; although Mr Henwood and Mr Sturgeon have failed in attempt- 

 ing to reproduce his results, and although results much resembling these 

 occur in cases where no electrical action is suspected. But we maj' re- 

 mark, that the conditions under which such voltaic effects are produced, 

 have not yet been attempted to be defined with any accuracy; and that, 

 till this is done, the reality of such agency can neither be verified nor 

 applied to geological speculations. 



A reflection which naturally offers itself upon this review of our recent 

 career, is this : — that different portions of the science of geology advance 

 with very different rapidity. Descriptive Geology is constantly and ac- 

 tively progressive : facts are accumulated by observers in every land ; 

 and though facts are, in truth, of no value, at least for any purpose of 

 science, except so far as they are reduced to some classification, yet, 

 on the other hand, sound classifications are perpetually, almost neces- 

 sarily, suggested, when observation is vigilant and persevering. Even if 

 we at first express our facts in terms of a false classification, we find af- 

 terwards the means of translating them into the language of a true one. 

 And the spirit of geological observation is so widely diffused, and so 

 thoroughly roused, that I trust we need not anticipate any pause or retarda- 

 tion in the career of Descriptive Geology. I confess, indeed, for my own 

 part, I do not look to see the exertions of the present race of geologists 

 surpassed by any who may succeed them. The great geological thcorizers 

 of the past belong to the Fabulous Period of the science ; but I consider 

 the eminent men by whom I am surrounded as the Heroic Age o{ geology. 

 They have slain its monsters, and cleared its wildernesses, and founded 

 here and there a great metropolis, the queen of future empires. They 

 have exerted combinations of talents which we cannot hope to see often 

 again exhibited, esfjcciallj' when the condition of the science which pro- 

 duced them is changed. I consider that it is now the destiny of geology 

 to pass from the heroic to the Historical Period. She can no longer look 

 for supernatural successes, but she is entering upon a career, I trust a 

 long and prosperous one, in which she must carry her vigilance into 

 every province of her territory, and extend her dominion over the earth, 

 till it becomes, far more truly than any before, an universal empire. 



Such are the prospects of Descriptive Geology ; — of the geology of 

 facts and classifications. To our knowledge of causes, we can look with 

 no such certainty of its progress being steady and rapid; or rather, wc 

 arc certain the advance must be slow, and may be often and long inter- 

 ruptcdv For it is not an advance, to suggest one or another hypothetical 

 cause or change, without assigning the laws and amount of the change : 

 it is hardly an advance even to calculate the results of our hypothesis on 

 assumed conditions. To obtain by induction, from adequate facts, the 

 laws of change of the organic and inorganic creation, — this alone can 

 lead us to those discoveries which must form the epochs of Geological 



