606 THE ILLINOIS GLACIAL LOBE. 



Hazelhurst and Polo rock is usually entered at 20 feet or less and the drift 

 is of variable constitution, there being- abrupt changes from gravel or sand 

 to till. There is a general capping of loess in that vicinity 6 or 7 teet in 

 depth. 



The public, water supply at Polo is obtained from a well 2,100 feet 

 in depth, which terminates in the Potsdam sandstone. It is situated in 

 a creek valley, and has but 37 feet of drift. The water is of pleasant 

 taste and is obtained in sufficient quantity for the needs of the town. A 

 well at French's tile yard at Polo penetrates about 80 feet of drift, The 

 upper 13 feet is loess and sandy material, but the remainder is a compact 

 till. East of Polo, on the divide between Elkhorn and Pine creeks, there 

 are several wells which penetrate about 60 feet of drift, They are in a 

 blue till from 20 feet downward to the rock. 



At Stratford the village well is 45 feet in depth without entering rock. 

 The railway cuttings immediately east of this village expose two sheets of 

 till separated by a fossiliferous silt. The upper sheet as stated above (p. 138) 

 is apparently much younger than the lower and is probably of Iowan age. 

 Within a mile east of Stratford rock ledges occur at an elevation as high as 

 the railway station (820 feet). 



At Oregon the wells range in depth from 20 to fully 200 feet, but are 

 usually about 30 feet, The public water supply was pumped from Rock 

 River until recentlv, but the Manual of American Waterworks (1897) 

 reports the present supply to be from wells. A railway cutting between 

 Oregon and Mount Morris exposes a buried soil below till at a depth of 

 about 25 feet. This probably separates the Iowan from the Illinoian till 

 sheet. 



At the village of Grand Detour wells on a terrace in the valley of 

 Rock River obtain water in gravel at a depth of 20 feet. 



At the village of Byron, which is situated on a terrace standing about 

 50 to 55 feet above Rock River, wells are usually sunk through a gravelly 

 sand to the level of the river. 



In the vicinity of Stillman Valley the drift is gravelly, and wells are 

 usually obtained at a depth of 25 feet or less. On the uplands bordering 

 the vallev in winch this village is situated rock is usually struck at a depth 

 of 10 or 15 feet. 



