THE BLOOMINGTON MORALISTIC SYSTEM. 277 



moraine and receives two tributaries which head in the moraine. There 

 are other tributaries of Spoon River farther north which also head in the 

 moraine, but these seem to have afforded only weak lines of escape for 

 glacial waters. 



The portion of the moraine bordering the Green River Basin in north- 

 ern Bureau and southeastern Lee counties, as already noted, is coated 

 heavily with sand on its outer face. The sand- extends westward from the 

 moraine down the Green River Valley, covering southeastern Whiteside 

 and northern Henry counties and occupying the low tract between Green 

 and Rock rivers. This sand is in all probability an outwash from the 

 moraine, being too extensive a deposit to be referable to the action of lake 

 waves. The sand apparently forms, over much of the district which it 

 occupies, a coating 10 to 20 feet or more in depth. The depth is so great 

 that natural exposures of underlying beds are rare and only a few wells 

 reach its bottom. It is therefore difficult to ascertain whether there is 

 much gravel outwash. Near the border of the moraine in northern Bureau 

 County there are, however, a few exposures of gravel at the base of the 

 sand which are thought to be an outwash from the moraine. The gravel 

 appears to extend but a few miles west, for in the vicinity of the county 

 line of Bureau and Henry counties wells indicate that the sand rests upon 

 a compact clay. 



At the head of the Green River Basin, in eastern Lee County, there is 

 a gravel plain, covering about 25 square miles, whose eastern border is in 

 the moraine. It extends back into the moraine a mile or more, along the 

 east and south branches of Willow Creek, and there connects with gravelly 

 knolls which dot the valley slopes and bottoms for 2 or 3 miles farther east. 

 This gravel plain extends northward along the west border of the moraine 

 to the south branch of Kite River at Steward. At this stream also the gravel 

 plain connects closely with gravelly knolls which extend some distance up 

 the valley into the moraine. The gravel extends only a few miles away 

 from the moraine, scarcely beyond the east border of Inlet Swamp. The 

 waters issuing from the ice sheet probably had sufficient strength to carry 

 the gravel down the rapid slope to Inlet Swamp, beyond which they could 

 carry only sand. There is considerable fall in the Green River Basin, but 

 it is irregularly distributed, so that drainage even now is very imperfect. 



