341 



The Tippecanoe an Infantile Drainage System. 



By Wm. A. McBeth. 



Streams first come into existence on a recently emerged or uncovered 

 land surface, with enough rainfall to leave a surplus for runoff after the 

 requirements for soil saturation and evaporation have been met. An up- 

 lift of part of the sea bottom, the drainage of a lake or the melting of an 

 ice sheet may produce the new surface on which the streams begin their 

 cycle of existence and work. 



Most of the streams of northern Indiana are in the youthful stage. 

 They came into being with the recession of the North American Ice Sheet 

 from that part of the State. If parts of the region retained areas of 

 marsh, pond or lake, the location of streams in such areas would be de- 

 layed until outlets could be made by the intrenchment of channels by out- 

 flowing waters to such depth that the impounded waters would be drained 

 off, when stream lines would be laid out on such newly uncovered lands. 



The Tippecanoe river between the abrupt bend on the northeast corner 

 of Pulaski County and Monticello in White County, with its tributaries, 

 furnishes a fine example of extremely young drainage. This section of the 

 river evidently traverses the bed of a former temporary lake which was 

 held in by a moraine at Monticello. Evidence of this lake remains in the 

 sand ridges, some of which seem to be beaches and others dunes numerous 

 in the region. The sudden change in the width and depth of the river val- 

 ley above Monticello also is significant of such a condition. The valley at 

 Monticello is almost exactly 100 feet deep, and from one-fourth to one- 

 half mile wide, and at Buffalo ten miles north of Monticello the channel 

 is about 25 feet deep and is without floodplain or bluffs. In brief, the 

 channel is just cut deep and wide enough barely to carry the flood waters. 

 The trusses of the highway bridges crossing the river in Pulaski County 

 can be seen miles away across the level prairie. The bridge floor at Wina- 

 mac is level with the streets of the town. The river has a steep slope 

 through this part of its course, the fall from Winamac to Monticello being 

 not less than 100 feet in thirty miles. 



The tributaries to the main stream in this region are examples of still 

 younger drainage. In following the road from Monticello to Buffalo the 

 way is over level country, except that where streams making their way 



