82 



ILUNOIS BIOLOGICAL MONOGRAPHS 



[180 



below the Champaign outlet. Algae and animal life were noted, but not as 

 abundantly as in the sludge bank at the junction of the Salt Fork and Bone- 

 yard (Fig. 21). 



Animals 

 Euglena genictdala, very few. 

 Paramoecium, one specimen. 

 Vorticella, very few. 



BluQ-green algae 

 Phormidium inundatum, abundant. 



Diatoms 

 Navictda salinarum, abundant. 



The scarcity of microscopic life and the total absence of clean-water 

 life is paralleled by the chemical condition of the water at this station, 

 where the examination of samples showed a total absence of dissolved 

 oxygen and the presence of multitudes of bacteria and gas-forming organ- 

 isms (see Tables X, XI). 



From the first iron bridge to the Brownfield woods bridge, a distance 

 of about a mile and a quarter, the stream is very shallow, less than a foot 

 in depth on the average, the water grayish with a sloppy appearance, and 

 the odor foul in places, though not as nauseating as below the first bridge. 

 Putrescent masses of soft, grayish-black or greenish matter, ranging in size 

 from a penny to a platter, may be seen floating down stream, held together 

 by algal strands. Brown masses observed on shore resembled human ex- 

 crement. The oily appearance of the surface of the water continues and 

 oily matter ascends when the bottom is disturbed. 



From the Brownfield bridge to the third (farmer's) bridge, a distance 

 of about three-quarters of a mile, the conditions are the same as above this 

 bridge (Fig. 38). Between the third bridge and the Cotton woods road 

 bridge, a distance of about a mile, the water is very shallow, scarcely 

 exceeding six-inches in depth, with gravel or sand bottom. Sludge bars, 

 of sand mixed with organic matter, are frequent, in many places occupying 

 more than half the width of the stream, the channel, a few inches to a foot 

 in depth, meandering over the bottom between these bars (Fig. 40). 



These bars presented a striking appearance, the stones and sand being 

 black from the decomposing organic matter, and the foul water algae 

 being arranged in long streaks, presenting in combination a striped green 

 and black design. The green algae is here very abundant, floating in the 

 stream or covering the shores. In places the encrusting material on the 

 shore margins is bright yellow. Everywhere along the stream the exposed 

 surface of the bottom is black from the decomposing organic matter, 

 which covers all objects and has been baked hard by the hot summer's 

 sun. The vegetation bordering the shore also shows the efi"ect of sewage 

 action, being either black in color or having the dried pieces of polluted 

 material attached to the lower part of the plants. The same conditions 

 prevail from the Cottonwoods road to the Mayview road, a distance of 

 about two miles. 



