111] FAUNA OF BIG VERMILION RIVER—BAKER 13 
of from half a mile to a mile an hour. The water was very low when these 
measurements were taken by the State Water Survey. In its course of 90 
miles to the Wabash River, the Big Vermilion River falls about 320 feet or 
3% feet per mile. It thus has a greater fall than either the Kankakee, 
which is 300 miles long and has a fall of 250 feet, or less than a foot per mile, 
or the Maumee River, which has a length of 150 miles and a fall of 154 feet, 
or about a foot per mile (Clark and Wilson, 1912). 
The water in the normal parts of the stream is usually clear at depths of 
one to two and a half feet, especially on the riffles. This condition was 
noted in Salt Fork east of Sidney, and in the Middle Fork. Above Sidney, 
except where the water is very shallow, the stream is murky and laden with 
fine silt. During times of high water the stream is in this condition in all 
parts of the Big Vermilion. The upper part of Salt Fork, from Urbana to a 
point six or eight miles down stream is always more or less brownish in 
color from the large amount of sewage, equalling as much as a third of the 
total volume, and putrient matter as well as an oily scum is usually to be 
seen on the surface. The shore of the stream is rendered very unsightly by 
the mass of filth that is despoiled above the usual level by high water. At 
St. Joseph, ten miles from Urbana, much the same condition is found. 
The upper part of the Salt Fork has been greatly modified by ditching 
and dredging. North of Urbana for the distance of a mile and a quarter 
above Crystal Lake Park a large ditch carries the surface drainage in a 
straight line to the park thus cutting off the tortuous windings of the 
original stream bed, which have been left as long, narrow, shallow ponds, 
reminding one of the ‘ox-bows’ so common in the valley of the Mississippi 
River. The bed of this ditch is about six feet below the general level of 
the surface. For several miles above this ditch the original stream has been 
deepened by dredging and the bed is now pretty generally five or six feet 
lower than that of the original stream. 
From Crystal Lake Park, Urbana, to a point near St. Joseph, the stream 
has been ditched to straighten the bed, leaving numerous ‘cut-offs’ of the 
old stream bed. This canal permits a better flow of water for the disposal 
of the sewage. Where not ditched the stream bed has been deepened. 
The ditching has greatly modified the original stream bed, providing a new 
and different kind of environment for the mussels and other aquatic life. 
It is probable that all of the old fauna was exterminated during the ditching 
operations and the sewage pollution provides an unfavorable environment, 
which the aquatic bottom life does not seem able or inclined to enter. The 
effect of sewage pollution may be seen all the way down the stream from the 
source of contamination. At St. Joseph, where the stream bed has not been 
modified, conditions are very bad, the mud in the bottom being filled with 
gas forming bacteria which are constantly causing bubbles of gas to break 
at the surface of the water. Were it not for the sewage pollution, the stream 
