THE MUSTOOKA TILL EIDGE. 323 



paraiso moraine. These glacial streams had a current sufficiently strong to 

 excavate a channel throughout nearly the entire length of the Kankakee 

 Basin, whose north bluff may still be seen rising 15 to 30 feet above the 

 Kankakee marsh. A current of this strength would seem to be entirely 

 adequate to cause the transportation of such sand deposits as are found on 

 the lower course of the Kankakee. It may be questioned, therefore, 

 whether these deposits may be referred with certainty to streams issuing 

 from the ice sheet at the time the Minooka Ridge was in process of forma- 

 tion. The evidence here, as in the case of the channels north of the Illinois 

 Valley, is scarcely sufficient to establish the occurrence of good drainage 

 conditions at that time. The peculiar association of this sand belt with a 

 bowlder belt is discussed below (p. 326). 



Inasmuch as the Iroquois moraine appears to have been formed either 

 contemporaneously with or subsequent to the Minooka Ridge, the character 

 of its outwash ma} r be found serviceable in drawing conclusions concerning 

 the outwash from the Minooka Ridge. 



On the outer border of the Iroquois moraine in Iroquois County, Illi- 

 nois, and also in Benton County, Indiana, the outwash is a fine sand which 

 has been transported to the lower parts of the Iroquois Basin and down the 

 valley of Sugar Creek, a southern tributary of the Iroquois. As this out- 

 wash is in a district lying outside the line of discharge for the glacial 

 streams which traverse the Kankakee Valley, it is less difficult to interpret 

 than the sands of the lower Kankakee. Its position is such as to be favor- 

 able for discharge of water if no lake were present, since there is a descent 

 away from the outer border of the moraine. Yet the fineness of the mate- 

 rial seems to indicate that very imperfect drainage conditions attended the 

 deposition of this moraine. The feebleness of discharge is thought to 

 indicate that lake-like conditions may still have persisted not only in the 

 Morris Basin but also in the Kankakee and Iroquois basins. 



On the outer border of the combined Marseilles and Minooka moraines, 

 in northern Kendall and southern Kane counties, there is an extensive 

 gravelly plain, to which attention was called in connection with the Mar- 

 seilles moraine. This plain has not as }^et been definitely connected with 

 any of the moraines of the late Wisconsin series. Three means of deposi- 

 tion need to be considered, as follows: (1) By streams flowing down the 

 Fox River Valley during the formation of the Valparaiso moraine and 



