694 LOUIS AGASSIZ. 



" There is, however, still one kind of evidence 

 wanting, to remove all doubt that the greater 

 extension of glaciers in former ages was con- 

 nected with cosmic changes in the physical 

 condition of our globe. Namely, all the phe- 

 nomena relating to the glacial period must be 

 found in the southern hemisphere, accompa- 

 nied by the same characteristic features as in 

 the north, but with this essential difference, 

 that everything must be reversed. The trend 

 of the glacial abrasions must be from the south 

 northward, the lee-side of abraded rocks must 

 be on the north side of the hills and mountain 

 ranges, and the boulders must have traveled 

 from the south to their present position. 

 Whether this be so or not, has not yet been 

 ascertained by direct observation. I expect 

 to find it so throughout the temperate and 

 cold zones of the southern hemisphere, with 

 the exception of the present glaciers of Terra 

 del Fuego and Patagonia, which may have 

 transported boulders in every direction. Even 

 in Europe, geologists have not yet sufficiently 

 discriminated between local glaciers and the 

 phenomena connected with their different de- 

 grees of successive retreat on the one hand; 

 and, on the other, the facts indicating the 

 action of an extensive sheet of ice moving 



