GENERAL AND INTERIOR DISTRIBUTION CV 



Especiall}^ significant in this relation are several cases in 

 which species of this list range southward in the eastern part of 

 the state upon the upper tributaries of the Kaskaskia and the 

 Embarras, for in so doing they simply follow southward the 

 course of the Shelbyville moraine which forms the boundary 

 between the Wisconsin and the lower Illinoisan glaciations in 

 east-central Illinois. The maps for Noturus flaviis, Hybopsis 

 dissi7nilis, H. kentuckiensis, and Stizostedion canadense are ex- 

 amples. 



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 glaciation more or less completely and to an 

 unmistakable degree. For example, 19 of our 94 collection 

 localities for the hogsucker (Catostomus nigricans) lie below the 

 Springfield parallel, but only three of them are in the lower 

 Illinoisan glaciation, and these are barel}^ within its borders. 

 Of our thirty localities for the short-headed red-horse (Moxostoma 

 breviceps) 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 glaciation, and that is on the upper Kaskaskia just 

 across the limiting moraine. The map for Notropis cornutus 

 shows one hundred and sixty-one localities from which 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 testifying to the same effect 

 will be found in the following list of fishes absent from this 

 characteristic southern Illinois district. 



Illinois Fishes Eare or wanting in the Lom-er Illinoisajj Glaciation 



Short-Dosed gar N. rubnfrons 



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 Sanger 



