1 FISHES OF ILLINOIS 



canon extends off to the east through Deer Park Glen. It is 

 about one fourth of a mile long, with perpendicular walls, and 

 is in the form of an elongated S. It terminates abruptly in a 

 cirque, open at the top and about 150 feet in diameter at the 

 bottom, with a fine spring of soft water bubbling up at its base. 

 In the wet season there is a waterfall of 25 feet which enters it 

 through a narrow chasm at the head. The walls of the cirque 

 are about 175 feet high. 



The stream is not of much value as a water-power on 

 account of the unsteadiness of its flow. It has no marshy 

 gathering ground, and the formations in its basin are mainly 

 compact till which yields but little water in seasons of drought. 



MACKINAW RIVER 



Mackinaw River rises in eastern McLean county. It flows 

 westward through the northern part of this county and across 

 the southern end of Woodford, then turning southwest into 

 Tazewell county. From the center of this county it bends 

 again to the west, following this direction for about 15 miles, 

 when it turns north and east, emptying into the Illinois a little 

 below Pekin. It is about 110 miles long, and drains an area 

 of about 1,200 square miles (Leverett). 



The upper part of the river lies inside the main ridges of the 

 Bloomington morainic system, and drains a plain which lies 300 

 to 350 feet above the Illinois. This section of the Mackinaw is 

 about 40 miles in length, most of its course being along the 

 southern border of the basin. In the first mile it descends 40 

 feet, but below this its fall averages about 3 feet to the mile. 



In its middle course the stream crosses the Bloomington and 

 Shelbyville morainic systems and the harrow plain separating 

 them. The width of the valley increases from about one fourth 

 of a mile in the inner part of the Bloomington belt to about one 

 half of a mile at the outer part, and to nearly a mile in its passage 

 across the Shelbyville moraine. Its fall is still rapid, about 3 feet 

 per mile. There are few tributaries, only a small area being 

 drained. 



In its lower course the Mackinaw River winds about in a 

 shallow channel, across the Illinois valley for a distance of 

 nearly 20 miles, making a descent of 75 feet. 



This stream is one 'of the most variable in the state in the 

 quantity of water it carries, since it is subject to great floods 

 in wet seasons and becomes nearly dry in seasons of drought. 



