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 derived 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 discovery it was found that the numerous articles of that description 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, near Mouth of Woolpert's Creek, Ky. This is part of an extensive deposit of bowlders and gravel with some Canadian pebbles, all cemented together by infiltrated carbonate of lime. From photograph by the author, reproduced in The 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 terminal 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
