CORRELATIVES OF CHAMPAIGN MORAINIC SYSTEM. 93 



In Johnson County this plain is traversed by shallow northeast-southwest depressions, in 

 which there are chains of elliptical knolls, and in one place an esker. These sags are now occu- 

 pied by small streams, High Bridge, Indian, and Hurricane creeks. Aside from these the plain 

 carries mounds such as Donnell and Doty mounds, already described, which are conspicuous 

 because of their unusual height. 



The drift seems to be largely a clayey till, though pockets and thin beds of gravel and 

 sand in it furnish supplies for wells at shallow depths. 



In portions of the plain bowlders are conspicuous. One belt already noted leads from a point 

 near Plainfield in Hendricks County almost to the White River valley at Indianapolis. A very 

 bowldery strip one-fourth mile wide and about 2 miles long lies in the southwest part of 

 T. 13 N., R. 4 W., in Johnson County. Another belt leads southwestward from Arlington in 

 northern Rush County along the northwest side of Little Blue River. Its course is nearly 

 parallel to the moraine and bowlder belt, leading past Rushville, and it may indicate a brief 

 halt of the ice margin in its withdrawal from this region. 



FRANKLIN ESKER. 



The Franklin esker heads in the southwest part of Franklin and leads southwestward 

 about 3 miles to the inner border of the moraine. At its southwest end it expands into a 

 fan-shaped plain or delta covering about one-fourth of a square mile, around which lies a 

 swampy depression 100 yards or more in width that separates it from the moraine. The esker 

 itself has its head in a swampy tract which extends 2 or 3 miles farther north than the 

 esker and which seems to have been formed by subglacial drainage in connection with it. A 

 few gravel knolls and low ridges 4 to 6 feet high in this trough are apparently referable to the 

 stream which formed the esker. 



The esker is opened extensively at its north end, where it consists of fine gravel with con- 

 siderable sand intermixed. The beds are horizontal with only a slight oblique bedding. The 

 character of the pebbles is shown in the table (p.' 90). 



The remarkable feature of this esker is its breadth, which in places exceeds one-eighth 

 mile, though its height is only 15 or 20 feet above border tracts. It may, however, have been 

 formed in a very broad tunnel in or beneath the ice sheet. 



