345 



thence duwii the Wabash to the Ohio. That there ^Yas an ancient west- 

 ward drainage along the East AYhite river is shown by the presence of 

 Tertiary gravel near Shoals, Indiana., that was brought from the east. But 

 the East White has a smaller channel than the neighboring part of the 

 Ohio, and no channel has been discovered near Madison to connect the 

 Ohio with the Mascatatuck Valley. It, therefore, seems a less favorable 

 course than that down the Ohio" (65: 112). 



Both Tight and Leverett agree in placing the head of the preglacial 

 lower Ohio near Madison, Indiana, thus making it a very humble stream 

 compared with the conditions of today. 



THE PIIEGLACIAL DRAINAGE OF THE BASINS OF THE UPPER 

 AND MIDDLE OHIO. 



Much work has been done in this basin, and much has been written 

 about it, and maps of local areas have been made to cover most of the 

 State, but no general map has ever been compiled. The bibliography, as is 

 apparent, contains a gi*at many excellent references to this region. Lev- 

 erett (65) and Tight (109) give the most complete discussion of the sub- 

 ject, and several other geologists have carefully discussed limited areas of 

 the basin ; and in view of the fact that so much has been written on the 

 subject only a few necessary points will be given here. 



The Ohio river is remarkable in many respects, for it presents much 

 variety in width, depth and other characteristics. The valley varies in 

 width from six miles, where the walls are low and gentle, to one mile, 

 where steep bluffs enclose it, and its depth ranges from less than 100 

 feet to 800 feet. Its bed presents a succession of riffles where its channel 

 runs over rock and shoals where the bed is upon a filling often 75 feet 

 deep. The number of narrow places where the bluffs are steep is remark- 

 ably large, as is shown on the maps (Pis. IV, V) by the terra "col" and 

 at such places the valley is young. Between the cols the present valley is 

 frequently crossed by old, wide valleys that extend for miles on either 

 side. Many of the tributaries, especially below Portsmouth, enter in oppo- 

 .site directions to their general course and many that rise close to the 

 main river, flow around for miles before entering, a fact indicating the 

 recent origin of the Oiiio (Kti): :!4). Mucli of the same may be said of 

 many of the tril)utaries, such as tlio Muskingum, Hocking, and the Alle- 

 gheny, for they are, too, "things of shreds and patches," liaving been prq- 

 duced by tlie union of portions of various stream systerns. 



