184 



is developing. In the southwest part of Spy Run Lake bottom occurs a 

 complex system of old channels which indicate the part of the lake last 

 drained. This is further shown by the more or less swampy condition 

 of this part. Below the lake bottom the system of meanders is so 

 complex that it is impossible to trace out, with any degree of certainty, 

 the different stages which occurred in the shifting of the stream bed. 

 Along the north side of the flood plain there is an old channel which 

 seems to be the oldest in the system. Near the south side, where 

 the stream is now located, the channels are less obscured, indicat- 

 ing that the creek has shifted its position from north to south and 

 suggesting that pi'obably the complex system of meanders is due to 

 this migration. A number of cross channels connect the old channel 

 on the north with the present one. In developing this system of meanders 

 the stream may have followed channel aie, leaving it at c and entering 

 its present channel, first at d and then at e and f. It then probably left 

 the old channel at g and crossed to its present one by the cross channel 

 gh, and at & by channel ho. Above this point the complexity increases, 

 the meanders are smaller, with a greater number of cross channels. 

 Four very young meanders lie south of the stream, one of which, rs, is 

 at times occupied by part of the stream, forming a small island. 



The Development of the Wabash Drainage System and the 

 Recession of the Ice Sheet in Indiana. 



By W. A. McBeth. 



The development of the Wabash drainage system has now been 

 worked out to such an extent as to show that it is not only a subject 

 of interest in itself, but also has an important bearing on the question 

 of the movement and recession of the North American ice sheet. The 

 whole of the axial stream, except a few miles near its mouth and perhaps 

 30,000 of the 33,000 square miles comprised in its basin, were buried 

 beneath the ice one or more times, and there is scarcely a tributary 

 which does not show plainly the effects of the influence of the ice sheet 

 in determining its course and its drainage area. 



Along the line of the lower Wabash, the earlier ice approached within 

 twelve or fifteen miles of the Ohio River, and almost to the limit of ice 



