THE GLACIAL THEORY. 



13 



blocks widely dispersed over the surface of our continents, 

 in other and far remote districts, between which the ocean 

 now exists, was it not that we should be entering upon 

 ground already well explored, and the facts concerning which 

 are universally acknowledged. When we observe immense 

 blocks of stone, analogous in construction with the rocks of 

 far remote regions, and existing in situations different from 

 those into which torrents of water might have brought them, 

 we are naturally induced to seek for other reasonings, capa- 

 ble of explaining these extraordinary effects. We find the 

 erratic blocks are largest, not to say most numerous, in the 

 regions most remote from their original rocks, and so it is 

 that in glaciers, we find the larger blocks most distant from 

 their original localities ; the argument w^hich presents itself 

 is, therefore — " the glaciers producing the effect in one 

 instance, may very probably have caused it in the other, at 

 an epoch when their distribution was more general and their 

 effects more remarkable." 



Mons. Agassiz is of opinion that the Swiss Alps were 

 formerly the centre of glacial action from which the distribu- 

 tion of erratic blocks and the formation of moraines took 

 place, throughout the north of Italy, Switzerland, &c. ; that 

 Norway was the centre from which erratic blocks were dis- 

 tributed throughout England, Germany, Poland, and Russia ; 

 and in the same way he conjectures that the present regions 

 of perpetual snows have been, and still are (though on a 

 diminished scale) the centres from which the same effects 

 took place throughout the principal portions of the globe. 



The revival of the glacial theory by Agassiz, has induced 

 several Geologists to conduct investigations to trace the 

 former existence of glaciers in our own country. 



Dr. Buckland and Mr. Lyell have established, in papers 

 read before the Geological Society of London during their 

 last session, the occurrence of moraines at Loch Traig, the 



