508 THE ILLINOIS GLACIAL LOBE. 



has rather imperfect drainage through the several tributaries of the Iroquois. 

 The streams are separated by poorly drained plains several miles in width, 

 in which, by systematic ditching, the productiveness of the soil has been 

 greatly increased. 



ATJ SABLE CREEK AND NETTLE CREEK. 



An Sable Creek (spelled also Aux Sable) has a drainage area of about 

 218 square miles, and enters the Illinois 4.7 miles below the junction of the 

 Des Plaines and Kankakee rivers. It drains much of the northern portion 

 of the Morris Basin lying between the Minooka till ridge and the portion 

 of the Marseilles moraine north of the Illinois River. It has widely branch- 

 ing headwaters which find their source in the Marseilles moraine. The 

 lower course follows the outer or west border of the Minooka Ridge south- 

 ward to the Illinois, and the east side of the watershed is very narrow. A 

 portion of this basin is included in the Morris topographic sheet. 



Nettle Creek, another stream draining the east slope of the Marseilles 

 moraine, enters the Illinois from the north at Morris, about 5 miles below 

 the mouth of Au Sable Creek. It also has widely branching headwaters 

 leading southeastward from the Marseilles moraine. The drainage area is 

 estimated by Cooley to be only 63 square miles. 



IMAZON CREEK, WAUPECAN CREEK, ETC. 



Mazon Creek, with an estimated drainage area of 540 square miles, 

 enters the Illinois at Morris, about 10 miles west from the head of the river. 

 Like Au Sable Creek, it has a widely branching headwater drainage whose 

 source is in the Marseilles moraine. The lower course leads northwestward, 

 draining at right angles to that of the several tributaries. There is a sandy 

 plain extending from the main creek eastward to the Kankakee, on which 

 there is no perceptible* dividing ridge. The headwater tributaries descend 

 rapidly, but the main stream is rather sluggish. Wide intervals between 

 the tributaries are imperfectly drained, but by systematic ditching the land 

 has been rendered very productive. 



Waupecan Creek and Hog - Run are two small southern tributaries of 

 the Illinois entering below the mouth of Mazon Creek and draining the 

 portion of the east slope of the Marseilles moraine lying between the Illi- 

 nois River and the Mazon watershed. Their combined area is onlv about 



