50 BULLETIN OF THE LABORATORIES 



large volume of water suddenly attempted to occupy a small 

 ravine. The result was that the first curvature was greatly in- 

 creased and a great undercut made at X, Deflected from this 

 point it struck the opposite or left bank of the ravine at M and 

 as it cut farther back into the great curve at OO it also cut 

 deeper and a small remnant of the left bank of the original ra- 

 vine was left at M. The outline of this channel is represented by 

 the broken line. 



After making the curve at 00 where considerable un- 

 dercutting is also shown, the waters took a straight shoot south 

 into the old ravine again. At the south end, at YY, the old ra- 

 vine, as shown by the dotted lines, made another sharp curve 

 similar to the one at G, and passed north between S and T to an- 

 other curve at HH, thus making the next loop of the sigmoid 

 which passed southeast through the point u. Since the rush 

 of glacial waters was not able to make the short turn at YY and 

 since the original surface level was lower than at H, they broke 

 over the divide and made a new cross channel tending northeast 

 in the direction Z u and choked up the old ravine between S 

 and T with sediment. As the lower level was reached and- the 

 velocity checked the lower courses of the intersected ravine 

 were filled up with material cut from the gorge above. Evi- 

 dence of these buried channels is found in many wells in the 

 village of Toboso just south of the river dam which is across 

 the present river at F. 



There yet remains the great question, why the river ever 

 left this second channel which it had cut out to such a great 

 depth and made a new one for itself straight across the rocky 

 barriers at gc, HS, and KT. If these were at the ends of the 

 loops or if the old channel was anywhere obstructed with drift 

 the explanation would be more simple. As it is there seems to 

 be but one solution to the problem to suggest and we believe 

 the facts very strongly support it. This region is just 

 on the eastern border of the Scioto lobe of the ice sheet. 

 No glacial till is reported south or east of this point in Ohio. 



