Stream, Diversion near St. Louisville, Ohio 341 



Licking county that the stream reversals in this area were ac- 

 complished pre-glacially as a result of a differential land move- 

 ment; Mr. E. R. Scheffel,'' from work on drainage changes near 

 Granville, Ohio, and Mr. K. F. Mather,^ from a similar study 

 of the Licking river near the ''Narrows," confirm this theory. 

 The present discussion proposes no new theories concerning 

 drainage changes; it directs attention to a case of reversal in 

 which glaciation may, to some extent, be a factor. 



Discussion 



The region here considered, a portion of Licking County, Ohio, 

 contains the head-water area of Rocky Fork which has its source 

 near the east wall of the North Fork of the Licking Valley, 

 about one and one-half miles northeast of St. Louisville. From 

 is place of origin the Rocky Fork flows in a northeasterly direc- 

 tion for about three miles, turning then to the east for two miles, 

 continuing thence approximately south, and joining the Lick- 

 ing River near Hanover. 



The Rocky Fork rises in a mature valley whose walls gradually 

 converge down-stream, coming closest together about six miles 

 from its source, where the present stream flows for some distance 

 through a narrow gorge; below this narrow segment, the walls 

 diverge to the south. Thus both up-stream and down-stream 

 from the gorge is a wider valley. 



The topographic map of this region (fig. 1) suggests that seg- 

 ments C and B of the Rocky Fork Valley were once connected 

 with the Licking; the trend of this portion of the valley, and the 

 fact that its walls flare towards the Licking Valley at St. Louis- 

 ville are the obvious details which support such an inference. 

 The stream which carved these segments flowed westward from 

 near the eastern end of B, 



But such irregularity in the width of a valley is sometimes the 

 result of varying hardness in the rock horizons through which 

 the stream is cutting. The rock structure itself, in this area, 

 is not of a nature that gives such differential responses to weather- 

 ing; the formations exposed are the Pottsville, Logan, and Black 

 Hand, none of which are here very resistant. 



^ Bull. Sci. Lab. Denison Univ., vol. xiv, pp. 162-174, 1909. 

 8 lb., pp. 183-187. 



