254 Proceedings of Indiana Academy of Science. 



were suggested from the name. "The Cut-off", applied to a sag-like opening 

 or col in the south half of section 35, which appears on Siebenthal's map of 

 Monroe County published in 1895. In this paper the liberty is taken of 

 making the term apply specifically to the sag, the expression "The Cut- 

 off Col" being used. Since the col has resulted from a physiographic action 

 in which a formerly continuous stream was divided into two sections, the 

 term "Cut-oft"" has been applied to each section, the upper section or stream 

 being named Upper Cut-oft" Creek and the lower section or stream being 

 named Lower Cut-off Creek. The physiographic action which divided the 

 parent stream into Upper and Lower Cut-off creeks was lateral planation 

 or the side-wise swinging of Salt Creek in the process of widening its 

 valley. This process took place in such a degree that Salt Creek actually 

 invaded the territory of the parent Cut-oft" Creek and the upper part was 

 diverted. Thus this case of planation piracy may well be called "Cut-off 

 Piracy". 



Evidence of Diversion of Upper Cut-off Creek. — That the valleys of 

 Upper and Lower Cut-off creeks were once one continuous valley and the 

 drainage of the present two stream systems was once a unit, is seen in the 

 present courses of the streams and the existence of the low sag which sep- 

 arates them. Upper Cut-off Creek, arising in the southeastern quarter of 

 section oO. flows west bearing slightly to the northward. In the southeast 

 quarter of section 35 near Phillips School, it turns abruptly through a flat- 

 bottomed opening and passes northward over the flat flood plain at Salt 

 Creek to Salt Creek channel near Fairfax. (Figures 1 and 2.) Lower 

 Cut-off Creek heads in a great sag. here called the Cut-off Col, one-fourth 

 mile west of where Upper Cut-off Creek debouches upon the flood plain of 

 Salt Creek. (Figures 3 and 4.) After extending west for three-fourths of 

 a mile the valley of Lower Cut-off Creek turns southward and opens 

 into Salt Creek valley. The upper part of Lower Cut-off Creek valley is 

 directly in line with the valley of T'pper Cut-oft" Creek. It may be said that 

 Upper Cut-off Creek has no valley after making the abrupt turn north- 

 ward through the opening at Phillips School, as it there debouches uiwn the 



Fig. I. View showing Upper Cut-oft" Creek where it turns abruptly north- 

 ward through the narrow, flat-bottomed opening at Phillips School. 



