[Vol XII Clark, Drainage Modificaiiois. 15 



In conclusion the reader is referred to the map, Plate III., 

 showin*::^ the "restored drainage" in tlie region under review. 

 In comparing the old with the new drainage it is not difficult to 

 see that the former has a much better right than the latter to be 

 described as the NORMAL system. Instead of, as at present, 

 four streams flowing directiy across the highest divide in this 

 part of the state, the restoration shows no streams crossing this 

 divide. Secondly, the restored drainage shows tliat in general 

 the axes of tributaries in any of the systems are parallel, which 

 is as it should be. Again, the old drainage shows uniformity 

 not only in axial directions, but also in the size and shape of its 

 hydrographic basins. In the present drainage these basins are 

 irregular in shape and extent, and in some instances almost in- 

 extricably intermingled. This irregularity is particularly evident 

 in the relation of the Wakatomaka basin to those of Owl Creek 

 and Rocky Fork. 



It will not be out of place to correlate the work that has 

 been described with that done by Professor Tight in adjacent 

 regions, reference to which has been made several times m the 

 course ot the descriptions. In this portion of the state Profes- 

 sor Tight has located the main axes of two quite important pre- 

 glacial streams, to one of which he has given the name "Old Mt. 

 Vernon River" and to the other, "Old Newark River." Both 

 these streams had general southwesterly courses and, in Knox 

 and Licking Counties, the furthest point West at which their 

 valleys are distinctly visible in the topography, approached so 

 near to each other that in the readjustment of drainage due to 

 advance of the glaciers cols have been cut down and the bas- 

 ins of the two streams intermingled. The work of the writer 

 has been to locate the divide between these two old streams 

 and to determine the changes incident to the breaking down of 

 this old divide during glacial times. It is but a small part in 

 the problem of restoring the pre-glacial drainage in the Ohio 

 River basin, but it is presented to those interested in the hope 

 that it is a distinct contribution to that problem. In closing, 

 I wish to express my appreciation of Professor Tight's kindly 

 interest in my work, and of his many suggestions by which I 



