OF DENISON UNIVERSITY. 55 



country, probably representing the slope of the elevated Creta- 

 ceous base level, rises as we pass to the south and the Scioto is 

 flowing in the direction opposite to that of the general slope. 



II. The Miami Drainage Channels and the Character 

 OF the Topography of that Region. 



The Great Miami as has been shown by Dr. Orton and 

 others is flowing in a postglacial channel. The Little Miami 

 presents another example of a small stream occupying a large 

 valley. From Dr. Orton 's work it would appear that this was 

 the preglacial valley of the Mad river which has its rise in the 

 Bellefontaine high land and is now deflected into the Great Mi- 

 ami. Mill creek also occupies an old channel. The exact cor- 

 relation of these old channels in the neighborhood of Cincinnati 

 is not satisfactorily determined. This much is evident, that 

 the valley of the Little Miami presents the characteristics of the 

 oldest of all the channels and if the drainage of the interior 

 basin reached the Ohio river in this vicinity it must have been 

 along this line. If the test of size and form is applied to this 

 channel it does not seem to be a fit outlet to such a- great basin 

 and other facts are also opposed to such a course. 



From the Ohio river at Portsmouth, Plate V, the water- 

 shed between the Scioto basin and the drainage systems of the 

 western portion of the state, runs west parallel to the Ohio into 

 Adams County, then north between Pike and Highland, west 

 through Highland to near Hillsboro, H, then almost due north 

 to the Bellefontaine highlands, B. As far as has been determined 

 this watershed presents an unkroken rocky axis from Ports- 

 mouth to a point between Springfield and London. From this 

 point north to the rock elevation at Bellefontaine the drift cov- 

 ers the rocky floor for many miles. It becomes evident, then, 

 that the line of preglacial drainage which will be called pregla- 

 cial Muskingum drainage must have been deflected to the north- 

 west at least as far as Springfield. The country traversed by 

 this supposed channel is buried with drift in most places to an 



