STRUCTURE OF THE DEIFT BORDER. 63 



Hillside exposures on the line of Pike and Adams counties, in R. 5 W., 

 have a bed of cherty gravel with occasional Canadian rocks resting on the 

 surface of the limestone, and covering it to a depth of 5 to 15 feet. Above 

 this gravel there is usually 40 or 50 feet of clay containing- very few pebbles. 

 The deeper exposures show it to be of a gray color, but the surface portion 

 is yellow. Capping this clay is a thin deposit of loess, separated in places 

 from the clay by a gray or ashy (Sangamon) soil. 



At the residence of A. Hill, 2 miles north of Baylis, on the crest of 

 the main drift ridge, a freshly excavated w ell was found to have the follow- 

 ing section: 



Section in well of A. Hill, 2 miles north of Baylis, Pike County, Illinois. 



Feet. 



Brown clay with lew pebbles 25 



Gray sand 10 



Gray clay, nearly free from pebbles 33 



Total depth 68 



At Baylis an experimental boring for water reached a depth of 90 feet 

 without entering rock or penetrating coarse material of any kind. The 

 upper 30 feet consisted of yellow clay and the remainder of fine sand. 

 This well is located on the crest of the main ridge, at an altitude about 400 

 feet above the Mississippi River. East and south from Baylis numerous 

 exposures are found in which a pebbly brown clay underlies the loess at a 

 depth of 8 or 10 feet. 



In the northeast part of the county, in the vicinity of New Salem and 

 Grriggsville, and thence north to the county line, the wells and natural 

 exposures reveal only a small amount of stony clay, the greater part of the 

 drift being nearly pebbleless. Rock is often entered at 30 or 40 feet, or 

 even less depth. 



In the vicinity of Time the ravines expose a pebbleless clay, probably 

 a phase of the loess, to a depth of 20 feet or more, beneath which there is a 

 slightly pebbly brown clay. The village well at Time reached the bottom 

 of this brown clay at a depth of 50 feet, and then penetrated 20 feet of blue 

 clay resembling putty, and terminated at a depth of 70 feet without entering 

 rock. At J. E. Dinsmore's farm, south of Time (sec. 26, T. G S., R 3 W.), 

 a well 60 feet in depth is largely through typical till, exposures of which 

 are to be seen in neighboring ravines. Mr. Dinsmore made a well in 

 sec. 23, in a ravine 30 or 40 feet below the level of the upland plain, which 



