MUSSEL PAUKA OF THE KANKAKEE BASIN. 



19 



impracticable to row up against the swift current in the dredged 

 Kankakee above its junction with Yellow River. 



Naturally we examined first those portions in which the condi- 

 tions had been least changed. Potato Creek is the southernmost of 

 several large creeks which empty into the east fork of the Kankakee, 

 and lies just north of A¥alkerton. The bed of the creek is hard 

 sand or gravel, and, being undredged, it still preserves those alter- 

 nations of swift and sluggish current, deep and shallow water, 

 coarse and fine bottom, which are conducive to mussel life. 



We found in it nine species of mussels, nowhere very thickly 

 bedded, but as many, perhaps, as would be expected in a creek of 

 the size, it being 8 or 10 feet wide, with the water nowhere more 

 than a foot or a foot and a half in depth. On examining these 

 mussels, the Anodontoides and the Anodonta were found infested 

 with Atax parasites and the distomid of Osborn; the other mussels 

 were free. 



Station 13. Pine and Yellowhanks Greeks. — These are two other 

 creeks of about the same size as Potato Creek and lying to the north 

 of Walkerton. But, although they presented conditions apparently 

 as favorable as those of the last station and were examined for long 

 distances on either side of the highway, not a single mussel could be 

 found in them, nor any dead shells, with the exception of one valve 

 of Symfhynota compressa in Yellowbanks Creek. 



Station D. The Fish Lakes. — These lakes really occupy a single 

 lake basin which is divided by narrow channels into four bodies of 

 water, known as the Upper Mud Lake, Upper Fish Lake, Lower 

 Fish Lake, and Lower Mud Lake, respectively. The two Fish Lakes 

 have each an area of about 100 acres and a maximum depth of 40 

 feet. The thoroughfare between them is 80 rods long and 15 or 20 

 feet wide, with a maximum depth of 2 feet, and has a good current. 

 The water in both of the lakes and the thoroughfare was clear and 

 quite warm. The bottom was marl, hard and firm in most places, 

 but very soft in a few spots. The shallow belt along the shore is 

 narrow, as a rule, though wider and more irregular in the Lower 

 Lake than in the Upper. The banks are high about halfway around 

 each of the lakes, but low and swampy for the other half, where 

 in each case it borders on the respective Mud Lake. There was the 

 usual lake vegetation around the shores — reeds, rushes, spatterdocks, 

 and some algse. 



Mussels were found abundantly everywhere. A. grandis was the 

 most common and was found everywhere mingled with the other 

 species. Most of the specimens were exceptionally large. Their 

 shells were also thick and strong; in fact, many of them possessed 

 shells of sufficient thickness for the manufacture of buttons. 



