OF DENISON UNIVERSITY. 21 



heavy deposits of drift in central, northern, and western Ohio, render 

 it very difficult to trace a northward line of discharge. There are at 

 least four possible^courses to be examined: i. Southward, down the 

 Scioto from Waverly to the Ohio, and thence down the Ohio; 2. 

 Northward along the axis of the Ohio Basin to Lake Erie; 3. North- 

 westward across western Ohio, along one of the several deep valleys 

 brought to light in that region by the oil and gas wells; 4. Northeast- 

 ward past the Licking Reservoir, and along the old valley (brought to 

 notice by Professor Tight in a former Bulletin), to the Muskingum at 

 Dresden, thence northward along or near the present valleys of the 

 Muskingum, Tuscarawas, and Cuyahoga to Lake Erie at Cleveland. 

 I have thus far been unable to rule out any one of these lines as an im- 

 possible one, or to reach any satisfactory conclusion concerning the 

 probabilities of the case. 



Of the three most influential factors likely to have been potent in 

 causing the changes of drainage in this region, uplift, stream piracy, 

 and glaciation, the last mentioned is the only one known to have been 

 an effective cause. That it is the only important factor is however by 

 no means certain. The question of the cause, or causes, of the 

 changes should therefore be left open. 



Washington, D. C, January iS, i8gj. 



