THE CINCINNATI ICE DAM. 



191 



So complicated are the forces of Nature that one discovery is 

 sure to lead to another, and the man of science soon learns that 

 he never exhausts attainable knowledge even in respect to the 

 simplest subject, and the student has made little true advance- 

 ment if he has not acquired ability to hold his mind wide open 



Map II, showing the partly filled preglacial channel of the Ohio, extending from Cincinnati to 

 the Big Miami at Hamilton. The figures show elevations above the sea. 



for the reception of any and all additional facts which may mod- 

 ify and enlarge his theories. In the present case most interesting 

 additions to our knowledge of the facts were made by Prof. Jo- 

 seph F. James, who called attention to the breadth and depth of 

 the valley running northward from Cincinnati to Hamilton, on 

 the Great Miami River, and to the comparative narrowness and 



