of denison university. 53 



10. The Scioto River ; Characters of its Upper and 



Lower Portions. 



The Scioto river rises near the northern watershed of the 

 state north of the Bellefontaine highland in Auglaize county, 

 flows east through Hardin into Marion county and then turns 

 south through Delaware, Franklin, Pickaway, Ross, Pike and 

 Scioto counties. The basin of the Scioto is generally low and 

 comparatively level. ^ It has been suggested that the Ohio 

 shales, Plate V, No. 8, are much softer than the other mem- 

 bers of the Ohio scale and that they have let down under the 

 influence of disintegrating and eroding agents and have thus 

 determined the lines of drainage and especially that of the Sci- 

 oto system. If this is true it would seem as though it ought to 

 hold for the southern part of the state as well as the northern 

 and middle portions. The hills of the western portion of Ross, 

 Pike, and Scioto counties rise iioo to 1200 feet A. T. , while 

 the Scioto river leaves the limits of the Ohio shales near Chilli- 

 cothe and enters the Waverly formation, Plate V, No. 9, and 

 follows its outcrop to the Ohio river, while the Waverly and 

 the outcrop of the Berea grit has been considered one of the 

 most resisting series, and in evidence of that it has been noted 

 that its outcrop has determined the watershed between the Mus- 

 kingum and Scioto systems and is represented by almost a 

 straight north and south line. The Scioto, however, as stated, 

 leaves the region of the Ohio shales and enters that of the 

 Waverly. 



The number of large streams, notably the Whetstone, 

 Alum Creek, Big Walnut and Big Darby, which flow for many 

 miles almost parallel to the Scioto before joining it and all ex- 

 cept the Big Darby, without rocky axes separating tlieir chan- 

 nels, seems to indicate that their courses have been determined 



^The watershed separating the hydrographic basins of the southern sys- 

 tems of the state are represented on Plate V by the heavy broken lines. 



