THE BLOOMINGTON MORAINIC SYSTEM. 247 



more than 10 or 15 feet high. This breaking up of a morainic belt into 

 several ridges at a salient curve is a common feature in this and other 

 morainic systems. In Ogle and northeastern Lee counties sloughs are a 

 conspicuous feature among the knolls. This outer belt is interrupted by 

 several gaps, occupied by streams, which head on its inner border and pass 

 through it to the lower outlying districts. Named in order from east to west 

 there are the following: Coon Creek, South Kishwaukee River, Owen's 

 Creek, Killbuck Creek, Kite River, and two branches of Willow Creek. 

 The crest of the morainic belt is absent for a mile or more at each of these 

 valleys. Apparently there were gaps of this width in it prior to the open- 

 ing of the drainage lines, for the slopes bordering the valleys carry knolls 

 and shallow basins such as characterize slightly eroded portions of the belt. 

 As shown below, these gaps were probably formed by streams issuing from 

 the ice sheet. The valley bottoms range in width from 60 rods up to fully 

 one-half mile, the broadest being at Kishwaukee River. 



The middle belt appears in western Kane County at Burlington. xV 

 morainic spur is found to lead southwestward from the inner border of the 

 outer belt into eastern Dekalb County, and to fade away 2 miles east of 

 Sycamore. It is about 1 mile in width, and is characterized by numerous 

 basins and low knolls, which give it fully as strong expression as the neighbor- 

 ing portion of the outer belt, from which it is separated by a narrow plain 1 £ 

 or 2 miles in width. There is also a basement ridge with a relief of perhaps 

 20 feet. For several miles west from the points where the Burlington spur 

 dies out, knolls 10 to 25 feet high are rather numerous and constitute a 

 probable line of continuation. Near Malta a definite riclge appears, which 

 leads southwestward to the outer belt in the southwest corner of Malta 

 Township, Dekalb County, and thence southward along the east border of 

 the outer belt, through western Milan and northwestern Shabbona town- 

 ships, passing just east of the village of Lee. For 3 or 4 miles in western 

 Milan Township it is combined with the outer belt, but elsewhere it is 

 separated from it by a narrow plane tract about a mile in average width. 

 In western Shabbona Township, Dekalb County, it becomes completely 

 united with the outer belt. This ridge, like the Burlington spur, is about a 

 mile in average width. It has a relief of 20 to 40 feet above the bordering 

 plane tracts. Its surface is gently undulating, but basins are rare, except 

 where it is closely associated with the outer belt in Milan Township. The 



