THE ERRATIC PHENOMENA. 397 



greatly contributed to retard our real progress in understanding the 

 general question of the distribution of erratics. 



It is well known that Northern Europe is strewed with boulders, 

 extending over European Russia, Poland, Northern Germany, Hol- 

 land and Belgium. The origin of these boulders is far north in Nor- 

 way, Sweden, Lapland and Liefland, but they are now diffused over 

 the extensive plains west of the Ural Mountains. Their arrange- 

 ment, 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 consequences to which we are 

 naturally carried by admitting that ice was also the agent in trans- 

 porting 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 satisfactory 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 satisfactory 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 applied to one 

 series of these phenomena, and the other cause to the other series. 

 An investigation of the erratic phenomena in North America seems 

 to me likely to settle this question, as the northern erratics occur 

 herein an undisturbed continuation over tracts (f land far more 

 extensive than those in which they have been observed in Europe. 

 For my own part, I have already traced them from the eastern 

 shores of Nova Scotia, through New England and the North West- 

 ern States of North America and the Canadas as far as the western 

 extremity of Lake Superior, a region embracing about thirty de- 



