28 Cincinnati Society of Natural History. 



If we go now to the east end of Eden Park, on the steep bluff 

 overlooking the river, we find the same rocky ledges. All along 

 the bank, farther than we can see, it is the same, and could we 

 look into the Kentucky banks just opposite, the same layers would 

 be found. But before being perfectly sure of what we suspect to 

 have been the case, let us journey to west of Clifton Heights, in 

 the neighborhood of the great quarries. Here, better than any- 

 were else, can be seen the evenness and regularity of these rocky 

 ledges. Great quantities of earth have been removed and great 

 holes have been cut into the solid limestone. Hundreds and 

 thousands of perch of stone have been carted away to form foun- 

 dation walls for innumerable buildings. If now we walk west- 

 ward we find the ledge continues under our feet, and we finally 

 pause on the brink of the precipitous bank overlooking Mill 

 Creek. Looking again westward, the same ledges crop out of the 

 bank. Not a doubt can now remain that there once stretched an 

 extensive plateau from the Kentucky shore back of Dayton across 

 what is now the Ohio valley, through Eden Park, over Deer 

 Creek valley, through Mt. Auburn, Clifton Heights, and across 

 Mill Creek valley to the opposite bank and far beyond. The 

 various valleys and ravines are seen to have been excavated in 

 this plateau, and the diversified aspect of the country is due to the 

 erosive powers of water, acting through immense periods of time. 

 There is one other force which has at one time had something to 

 do with altering the appearance of the country hereabouts, and 

 that is moving ice. When during the glacial era a large part of 

 the North American continent was covered with an immense mass 

 of ice, in places five, six, ten thousand feet thick, it was a power- 

 ful erosive agent. For it swept over the surface of the land, plow- 

 ing it out here, filling it up there, overtopping hills, or sweeping 

 round projecting or insurmountable points. 



At the close of this period the whole face of the country bore 

 a very different aspect from what it had previously borne. In 

 places immense piles of debris remained, forming banks many 

 miles long, and many feet high. When these were in the beds of 

 former streams, it became necessary for the stream thus barred out 

 to seek a new channel, and it varied from its former course more 

 or less, in accordance with the amount of material left in its bed. 

 Many streams were compelled to form entirely new channels, but 

 others had to carve new courses only in places here and there. 

 The Ohio river seems to be one of those placed in the latter cate- 



