Ixiv FISHES OF ILLINOIS 



southwest, a distance of about 60 miles, emptying into the 

 Wabash River in Vermilion county, Indiana. Of this length 

 45 miles lie in Illinois. It drains a narrow strip covered by the 

 Champaign till-sheet lying between two moraines, the northern 

 of which completely separates the drainage basin of the Little 

 Vermilion from that of the Vermilion proper. Its total drainage 

 area is 213 square miles, 179 of which are in Illinois. It rises 

 at an altitude of 710 feet, and falls 30 feet in its first 4 miles. 

 In the next 9 miles a descent of only 10 feet is made, below 

 which a fall of 50 feet occurs in 4 miles. The descent then 

 becomes more gradual and the stream crosses the state-line at 

 an elevation of about 500 feet. In its upper part it is little 

 more than a prairie drain, but it becomes of more importance 

 farther down, where the banks are 75 to 100 feet high and lined 

 with strips of timber 1 to 3 miles in width. 



EMBARRAS RIVER 



Embarras River, 132 miles long, drains an area of about 

 2,400 square miles in eastern Illinois. Its source is in the 

 Champaign morainic system, immediately south of the city of 

 Champaign. For about 20 miles it flows between the outer 

 and the main ridges of the Champaign system, then cuts through 

 the outer ridge in northern Douglas county. Thence it bears 

 southeast, for about 10 miles, to a small till ridge correlated 

 with the Cerro Gordo moraine, crossing this in southeastern 

 Douglas county. Its course is then slightly west of south for 25 

 miles, at which point it leaves the Shelbyville or earliest Wis- 

 consin sheet of drift, continuing southward 25 to 30 miles 

 farther, to the neighborhood of Newton, where it changes to 

 the southeastward and maintains this course to its mouth, a 

 distance of 50 miles. 



The river rises at an altitude of 750 feet, while its mouth lies 

 only 395 feet above tide, making a total descent of 355 feet, or an 

 average descent of two and a third feet to the mile. In the last 

 53 miles, however, the fall is scarcely more than a foot to the mile. 



The upper part of the river, lying within the Wisconsin drift, 

 drains only a narrow strip and has but few tributaries. This sec- 

 tion of its basin is mostly prairie with woodlands skirting the 

 larger streams, and the soil is a deep, black, and very fertile loam. 



Upon emerging from the Wisconsin drift, the river enters 

 at once a much broader valley which appears to have been 

 excavated prior to the Wisconsin stage of glaciation, for the 



