M. Agassiz on Glaciers, Moraines, and Erratic Blocks. 383 



come when we shall be able to determine the geological period 

 at which the sun began to exercise an influence upon the sur- 

 face of the globe, so considerable as to produce the differences 

 which now exist between the different zones, without these 

 effects being neutralized by the influence of the internal heat, 

 from which the eartli must for a time have enjoyed a very uni- 

 form temperature over all its surface. 



This theory, I fear, will not be adopted by a number of our 

 geologists, who have settled and confirmed opinions on the 

 point ; but I anticipate it will be with this question, as with 

 many others which assail old and established views. At all 

 events, whatever opposition it may experience, it will remain 

 true that the numerous new facts relating to the transport of 

 blocks which 1 have pointed out, and which may be studied so 

 easily in the valley of the Rhone and the environs of Neuchatel, 

 have brought the discussion into wholly different ground from 

 that on which it has hitherto been debated. 



When M. de Buch for the first time affirmed, in opposition 

 to the formidable school of Werner, that granite is of Plutonic 

 origin, and that the mountains had been uplifted, What did 

 the Neptunists say ? At first he sustained his position alone ; 

 and it has only been by his defending it with the innate powers 

 of genius, that he has made it triumph. It is happy for us, 

 that in scientific discussions, numerical majorities at first have 

 never decided any question. 



The form into which I have thrown these observations will, 

 I trust, banish all discussion on the subject at the present mo- 

 ment ; and as, at the same time, I cannot hope that I have 

 convinced every one of the truth of my views who have heard 

 them for the first time, I propose the Geological Section as the 

 most suitable for any discussion which may follow. I shall 

 then make it my business to meet any objections which may 

 be started ; and, for the sake of truth, I earnestly solicit them. 



I 



