238 THE ILLINOIS GLACIAL LOBE. 



River below this point. The small amount of outwash shown at the border 

 of the moraine seems to make it doubtful if the gravel belt along the river 

 was chiefly formed as morainic outwash. The gravel may be largely a 

 residue from the cutting down of the sheet of drift outside the moraine. 



Kaskaskia and Embarras valleys have, as a rule, either silt or till 

 banks where they border the ridges of this morainic system. It is probable 

 that the ice sheet had feeble outwash at these valleys, as they are favorably 

 situated for receiving any outwash which may have been contributed from 

 the moraine, the course of the Kaskaskia being for several miles but a short 

 distance outside the Outer Ridge and the course of the Embarras being for 

 an even greater distance just outside the Middle Ridge. 



Near the head of Bruillett's Creek, in northern Edgar County, the plain 

 outside the moraine has an area of several square miles which is underlain 

 by gravel. Tributaries of Bruillett's Creek lead down from the moraine into 

 this plain and lose their waters in its gravel. In some cases these streams 

 do not maintain a channel in this plain. It is not entirely certain that 

 this gravel is an outwash from the moraine, since the moraine itself is of a 

 stiff clayey constitution on the immediate borders of the gravelly plain. If 

 the moraine had a gravelly constitution on this border, as it does at Mahomet, 

 the case would seem more certain. 



Along the Wabash River Valley extensive gravel terraces occur both 

 above and below the points where the ridges of this morainic system cross. 

 Possibly a portion of the gravel connects with this morainic system, but by 

 far the larger part connects with moraines of later date which cross farther 

 up the valley. 



Near Bloomingdale, Indiana, a gravel-filled valley not now occupied by 

 a stream leads southward from the moraine across Leatherwood Creek to 

 the valley of Rocky Run, a distance of 2 miles, and thence continues down 

 Rocky Run to the Wabash Valley. The portion not occupied by a stream 

 is bordered by bluffs 30 to 50 feet in height, and has a width of from one- 

 third to one-half mile. The relation of this valley to the Champaign 

 morainic system is not definitely settled. It is perhaps an interglacial val- 

 ley, whose upper course has been overridden and concealed by the Cham- 

 paign drift sheet. The gravel filling in its bottom may prove to be an 

 outwash from the moraine, though this is not entirely certain. It is not 

 evident why Leatherwood Creek chose a passage westward instead of turn- 



