THE CINCINNATI ICE DAM. 



189 



the snail's pace at which a glacier moves, this bowlder must have 

 been in the territory of Ohio for an enormous period of time, long 

 enough for even a bowlder to become naturalized. If, however, 

 the Canadians should claim it as a fugitive from justice, they 

 would have a prior right, for the ledges from which it was de- 

 rived are near Thessalon, in Ontario, north of Lake Huron. In 

 searching for bowlders in southern Ohio, I was accustomed to 

 hear them referred to as " niggerheads." In the progress of dis- 

 covery it was found that the numerous articles of that descrip- 

 tion which in recent times Kentucky had furnished to Canada 

 were in payment of a debt under which the Dominion had placed 

 the southern commonwealth long ages before. 



It is important to note that my discovery of Canadian bowlders 

 on the hills of Kentucky was not the first which had been made 

 there. As far back as 1845 Prof. Locke had noted the post-glacial 

 conglomerate called Split Rock, below Woolpert's Creek, opposite 



Fig. 2. Split Rock, neae Mouth of Woolpert's Ckeek, Ky. This is part of an extensive 

 deposit of bowlders and gravel with some Canadian pebbles, all cemented toffether by 

 infiltrated carbonate of lime. From photograph by the author, reproduced in Tlie Ice Age 

 of North America, p. 345. 



Aurora, Ind., but had regarded this as the remnants of local 

 strata which had been nearly worn away. In 1872 also, Mr. 

 Robert B. Warder had suggested that this was possibly a termi- 

 nal moraine. Still later Dr. Sutton, in 1876, and Prof. Cox, in 

 1878, had noted similar deposits near the summit of the Kentucky 

 hills, on Middle Creek opposite Aurora, and had attributed them 

 correctly to glacial action during the maximum stage of the great 



