lxii FISHES OF ILLINOIS 



which buries the old stream bed to a depth of 60 or 70 feet, and 

 is bounded by bluffs rising from 100 to 200 feet above the river. 

 The Illinois section of the Wabash has a comparatively sluggish 

 current, its fall being less than eight inches to the mile. 



Two, and in some places three, different levels are distin- 

 guishable in the Wabash valley to-day. The bottom-lands of 

 the river subject to overflow at ordinary high water are from 

 twelve to fifteen feet above the stream, and at about the same 

 height above these are the second bottoms, covered with water 

 only by exceptional floods; and in some places a terrace level 

 may be traced half-way up the bordering bluff*. The river 

 flows for the most part along the western side of its valley, 

 occasionally, indeed, quite close to the bluffs, leaving the bot- 

 toms largely on the Indiana side of the stream. The bed of the 

 river is often. rocky and the current locally swift, and rapids 

 greatly interfered in early days with the use of the stream for 

 transportation purposes. The waters of the Wabash are, like 

 those of the Illinois and the Kaskaskia, commonly brown and 

 opaque with suspended silt, never clearing even at the lowest 

 stages; and the same is true of most of its tributary streams, 

 especialty those of the lower Illinoisan glaciation. 



VERMILION RIVER 



Vermilion River drains an area of about 1,435 square miles 

 in Ford, Champaign, and Vermilion counties in Illinois, and a 

 small section of Fountain and Warren counties in Indiana. It 

 rises only a few miles from the source of a river of the same name 

 which flows northwest into the Illinois, to distinguish it from 

 which it is often called the Wabash-Vermilion or the Big Ver- 

 milion. Its course is generally south and east, and it empties 

 into the Wabash 10 miles beyond the Indiana line. It has a 

 length of about 81 miles, and a fall of 320 feet. Its source is 

 in the midst of the Bloomington morainic system at an eleva- 

 tion of 800 feet. It flows thence southward between two ridges, 

 known as the Roberts and Melvin ridges, and passes through the 

 latter ridge, falling 70 feet in this distance of 17^ miles. At 

 this point it receives a tributary of about the same length from 

 the west, which is known as the West branch of the Middle 

 Fork. This branch also rises at an elevation of 800 feet and 

 drains a sag or narrow plain between the Melvin ridge and the 

 outer moraine of the Bloomington system. From this union the 

 stream takes a southeastward course across the northeast corner 



