Nov., 1910.] An Open Valley near Harrishui'g, 0. 213 



a larger valley and a broader valley floor upstream than has this 

 little stream in question. Thus we eonclude that it must have been 

 made by a much larger and longer stream. 



Another theory is that the Darby itself flowed through this 

 valley at one stage of its development, and later changed its 

 course for the present one. But the question arises, if the Darby 

 had this valley for its course in some period of its history, why is 

 the valley so much smaller than the present Darb}' valley? The 

 Darby valley is from a quarter to one-half mile or even more in 

 width, while the open valley is only one-eighth of a mile in width. 

 Again, the Darby for many miles farther uy its course has a much 

 wider valley than this open valley. This width of the Darby 

 valley north of the point where the open valley enters, opposes 

 the idea that the river in some period of its histor}' flowed through 

 the open valley. So we must abandon that theory. 



A further solution is proposed, namely, that at an early period 

 in its history, perhaps while still under the ice, the Darby divided 

 its course so that about one-third or one-fourth of its waters went 

 through this present open valley, while the greater portion of the 

 river flowed in its present channel. After time enough to make 

 this valley, the eastern branch succeeded in cutting below the 

 western and thus captured its w^aters. The open valley was 

 thereby left as an abandoned channel of a portion of the Darby. 

 The floor of this open valley at the point where it joins the Darby 

 is about forty feet above the present level of the flood plain of the 

 Darby. This shows how the Darby in its eastern branch was able 

 to take the waters of the western branch. 



These open valleys occur along the Scioto River in several 

 places in its course and are attributed to the same cause as the one 

 along the Darby. The division of the streams sometimes, no 

 doubt, took place under the ice sheet during its last stages. Some- 

 times an island may have been the cause, separating the stream 

 into parts and causing it to find two separate covirses. In such 

 cases the inter-stream area should be sandy. 



This Big Darby valley has been abandoned long enough for 

 the present northward stream to have graded a slope for its 

 entrance into the Darby w^hile the stream following southward 

 down the slope once led by the old stream now has in its lower 

 course a considerable flood plain some thirty or forty feet below 

 the abandoned valley floor, leaving the old flood plain beautifully 

 terraced as is that of the Darbv itself. 



