256 Proceedings of Indiana Academy of Science. 



wider in the vicinity of Fairfax than it is for several miles either above 

 or below this locality. No terraces flank the south side of the valley 

 here, but on the inside of the great valley-bend more than the usual amount 

 of terrace material is present. This abrupt turn of the valley certainly 

 favored lateral planation on the outside of the great bend. The extra- 

 ordinary concave bluff-line, with its farthest south extension near Phillips 

 School, is a rather striking indication of the concentration of waters against 

 the south side of the valley. 



Another feature which enters into the problem is the fact that there 

 hab been much more water flowing in Salt Creek valley at times during 

 the past than there is at present. Salt Creek is a small sluggish stream 

 meandering in a valley rather too large for it. The Pleistocene valley-fill 

 material and the flanking terraces are proof that the valley once was a 

 sluice-way for the exit of glacial waters. No doubt during the melting 

 seasons of the glacial ice near the headwaters of this valley, the valley was 

 in a highly flooded condition, and the stream that occupied it was much 

 larger than the present one. Lateral planation must have taken place on a 

 much greater scale during this time than at present. The much larger 

 Pleistocene stream must have brushed all outside turns of the meandering 

 valley with considerable vigor. The great curve cut out in the south blutf 

 south of Fairfax must have been made during this time, as the curve 

 seems unusually large to have been made by the present rather feeble 

 stream. The present position of the stream channel has no relation to this 

 great curve. In one or two meanders in the flood-plain the present stream 

 does come against the south bluff in the northern part of section 36, but 

 this touching of the bluff in these two places has not yet destroyed the 

 symmetry of the great curve in the wall-like bluff. 



There is a strong probability that the parent Cut-off Creek received a 

 small tributary from the northeast in the vicinity of the present site of 

 Phillips School. The territory of this stream was invaded by the over- 

 widened valley of Salt Creek. The sags, one near the center of section 35 

 and one in the N. W. quarter section 35. are indications that the upper 

 portions of two small tributaries of Cut-off Creek became engulfed in the 

 widened valley of Salt Creek. In the case, however, of the tributary 

 which came in near the present site of Phillips School, the whole of the 

 area of the tributary became a part of Salt Creek valley. When the great 

 curve had advanced far enough to come into the valley of Cut-off Creek or 

 approach it through the valley of the tributary, piracy of the upper part 

 of the parent Cut-off was effected. It is believed that the piracy was 

 effected during the Pleistocene period. 



Static Rejuvenation of Upper Cut-Oft Creek Basin. — The virtual division 

 of the parent Cut-off Creek into Upper and Lower Cut-off creeks allowed 

 the drainage waters from about 260 acres to enter Salt Creek directly, in- 

 stead of having to flow some two miles farther before entering Salt Creek 

 valley. Upper Cut-off Creek at the time of its diversion must have been 

 perched 00 to 95 feet above Salt Creek valley. This is specifically indi- 

 cated by the elevation of the old abandoned portion of the parent stream 

 valley which is now the divide between LTpper and Lower Cut-off creeks. 

 (Figure 3.) The valley of Salt Creek at the place of the entrance of 

 Upper Cut-offCreek upon it is 515 feet above sea level. The abandoned 



