STRUCTURE OF THE DRIFT BORDER. 59 



thought to have entered rock only 40 feet; it also is reported to have been 

 largely through clay. 



On the elevated district near Payson wells penetrate alternations of clay 

 and gravel to a depth of 60 feet or more. A well made by Mr. Barnard, 

 1 mile west of Payson, after penetrating 60 feet of clay and gravel, entered 

 a red clay, apparently formed from the limestone which underlies that 

 region. In some places the gravelly beds of the drift seem to rest directly 

 upon undecayed rock surface. 



A small drift ridge is traceable southeastward from the village of New- 

 ton (Adams post-office), on which wells have been sunk to a depth of 75 or 

 100 feet without entering rock. The town well at Newton is reported to be 

 mainly through clay, with a few feet of gravel at bottom. A well at Mrs. 

 Wittemeyer's, on the crest of the ridge, about a mile southeast of Newton, 

 reached a depth of 82 feet and apparently passed through a buried soil 

 between sheets of till. Exposures of a buried soil are to be seen near the 

 level of the base of the ridge in the road leading south from Mrs. Wittemeyer's, 

 in sec. 35, T. 2 S., R. 7 W., but at that place it is underlain by sandy gravel. 

 The following is a section of the well as reported by the owner: 



Section in well at Mrs. Wittemeyer's, a mile southeast of Newton, Adams County, Illinois. 



Feet. 



Yellow clay without pebbles (Iowan) 10 



Pebbly yellow clay (Illinoian) 30 



Mucky gray clay (probably a Yarmouth soil) 7 



Sandy and pebbly clay grading downward into sand (Kan&an) 3d 



To tal depth 82 



On the plain northeast of this ridge, from the village of Burton east- 

 ward to Liberty, the ravines expose a yellowish gummy clay, containing 

 few pebbles to a depth of 50 feet, which is referred to the Illinoian. There 

 do not appear to be large pebbles or bowlders in such number as usually 

 occur in the typical till. 



Farther south, in the vicinity of Plainville and eastward from that 

 village, the ravines expose a large amount of cherty gravel and cobble in 

 the lower part of the drift, but the upper part, to a depth of 20 feet or 

 more, is usually a clay containing but few pebbles. This phase of the 

 drift, as noted below, extends across Pike County and characterizes the 

 extreme border of the Illinoian sheet. It is probable that the chert is a 

 residual product from the cherty limestones of that locality. 



