THE TOPOGRAPHY AND IIYDIKH IKAP1IY OF ILLINOIS XXV11 



PECATONICA RIVER 



Pecatonica River rises in Iowa county, Wisconsin, in the 

 driftless area, and flows south, entering Illinois in the northwest 

 corner of Stephenson county. It then flows in a course a little 

 south of west to Freeport, where it turns westward, entering 

 Winnebago county near the center of its western boundary. 

 Another turn is then made, to the north and east, the stream 

 finally emptying into Rock River at Rockton. The Pecatonica 

 is about 150 miles long, over half of this distance lying in Wis- 

 consin. Its drainage basin covers 2,225 square miles, of which 

 780 are in Illinois. Its discharge in ordinary low water is 

 about 940 cubic feet per second, and the average flow for the 

 year is estimated to be over 2,300 cubic feet per second. Almost 

 all of that portion of the basin lying in Wisconsin is included in 

 the driftless area, the river entering the Ulinoisan drift just 

 above the Illinois state-line. It flows through this drift until, 

 at a point 10 miles above its mouth, it enters the Iowan drift. 

 For 10 or 15 miles above this point, however, it follows closely 

 the northern boundarj^ of this drift. The country which the 

 Pecatonica drains is rolling, partly timber and partly prairie. 



The Indian name of the river (spelled Peeka-ton-oke on the 

 old maps) is said by some authors to mean " muddy," and by 

 others to mean " crooked. " The river, especially in its lower 

 portion, would fit either or both. The fall of the river averages 

 only about half a foot per mile, and throughout its course it 

 curves and winds about, not abruptly but in long undulating 

 turns, through its rich alluvial bottoms, which in some places 

 spread out to a width of 3 miles. Its earthen banks are low 

 and rounded, and covered with heavy timber. 



KISHWAUKEE RIVER 



Kishwaukee River is formed by two branches which unite 

 about 12 miles above its mouth. The northern branch rises in 

 the Wisconsin moraine in central McHenry county, and the 

 southern in the same moraine in southern DeKalb county. 

 Each of these branches is about 50 miles long, the whole system 

 draining about 1,644 square miles. The lower part of the river 

 lies in drift of the Iowan age, while the upper parts are in that 

 of the Wisconsin age. The northern branch falls about 25 feet 

 in the first 3 miles, and below this the descent averages two and 

 a half to three feet per mile. The southern branch is a little 

 swifter, with an average fall of about 4 feet per mile. The 



