100 Local Alpine Boulders. 



erratic boulders, there are several separate centres of their 

 distribution to be distinguished in Europe. But there is 

 another question connected with this local distribution of 

 boulders which requires particular investigation, the confusion 

 of which with the former has no doubt greatly contributed to 

 retard our real progress in understanding the general ques- 

 tion of the distribution of erratics. 



It is well known that Northern Europe is strewed with 

 boulders, extending over European Russia, Poland, Northern 

 Germany, Holland, and Belgium. The origin of these bould- 

 ers is far north in Norway, Sweden, Lapland, and Lief- 

 land ; but they are now diffused over the extensive plains west 

 of the Ural Mountains. Their arrangement, however, is such 

 that they cannot be referred to one single point of origin, 

 but only in a general way to the northern tracts of land 

 which rise above the level of the sea in the arctic regions. 

 Whether these boulders were transported by the same agency 

 as those arising from distinct centres, on the main Continent 

 of Europe, has been the chief point of discussion. For my 

 own part, I have indeed no doubt that the extreme conse- 

 quences to which we are naturally carried by admitting that 

 ice was also the agent in transporting the northern erratics 

 to their present positions, has been the chief objection to the 

 view, that the Alpine boulders have been distributed by 

 glaciers. 



It seemed easier to account for the distribution of the 

 northern erratics by currents ; and this view appearing satis- 

 factory to those who supported it, they at once went further, 

 and opposed the glacial theory even in those districts where 

 the glaciers seemed to give a more natural and more satis- 

 factory explanation of the phenomena. To embrace the 

 whole question it should be ascertained 



First, Whether the northern erratics were transported at 

 the same time as the local alpine boulders, and if not, which 

 of the phenomena preceded the other ; and again, if the same 

 cause acted in both cases, or if one of the causes can be ap- 

 plied to one serie s of these phenomena, and the other cause 

 to the other series. An investigation of the erratic pheno- 

 mena in Norih America seems to me likely to settle this 



