C FISHES OF ILLINOIS 



the lower Illinoisan glaciations in east-central Illinois. The maps 

 for Noturus flavus, Hyhopsis dissimilis, H. kentuckiensis , and Stizo- 

 stedion canadense are examples. 



That this coincidence of distribution and surface geology points 

 to a true explanation is further shown by the maps for twenty-two 

 other species which range more definitely to the southward than the 

 foregoing twelve, but which nevertheless avoid the southern glacia- 

 tion more or less completely and to an unmistakable degree. For 

 example, 19 of our 94 collection localities for the hogsucker (Catos- 

 tomus nigricans) lie below the Springfield parallel, but only three of 

 them are in the lower Illinoisan glaciation, and these are barely 

 within its borders. Of our thirty localities for the short-headed red- 

 horse {M 0X0 stoma hreviceps) only two are in this glaciation, and these 

 are near its boundaries on the Embarras and the Kaskaskia. The 

 very abundant minnow Campostoma anomalum was taken by us from 

 one hundred and sixty localities, thirty-one of which are south of the 

 Sangamon and eight of them from the non-glaciated area of the Cairo 

 district, but only one of the entire number is within the lower glacia- 

 tion, and that is on the upper Kaskaskia just across the limiting mo- 

 raine. The map for Notropis cornuttts shows one hundred and sixty- 

 one localities from wdiich collections of this species were made, ninety 

 of them below the Sangamon and twenty-nine in the Cairo district, 

 but only three are in the southern glaciation. Other species testify- 

 ing to the same effect will be found in the following list of fishes ab- 

 sent from this characteristic southern Illinois district. 



Illinois Fishes Rare or wanting in the Lower Illinoisan Glaciation 



Short-nosed gar A^ riibrifrons 



Common bullhead Spotted shiner 



Stonecat Storer's chub 



Lake carp River chub 



Quillback carp Pike 



Common sucker Menona top-minnow 



Hogsucker Trout-perch 



Short-headed red-horse Pumpkinseed 



Stone-roller Small-mouthed black bass 



Red-bellied dace Sauger 



Notropis cayuga Yellow perch 



A'^. heterodon Banded darter 



Straw-colored minnow Rainbow darter 



Notropis gilberti Fan-tailed darter 



Spot-tailed minnow White bass 



Common shiner Yellow bass 



Notropis jejunus Miller's thumb 



