WELLS OF ADAMS COUNTY, ILLINOIS. 715 



At Mendon the public water supply is from a well 1,010 feet iu 

 depth, from which water is pumped to a tank. This well passed through 

 about 20 feet of loess and glacial drift, beneath which a deposit of orange- 

 colored sand, presumably preglacial, was found, which extends to the lime- 

 stone at 70 feet from the surface. Another well, at the public square, on 

 ground 20 feet higher than the deep well, also penetrated a large amount 

 of sand and entered limestone at a depth of 94 feet. Samples of this sand 

 examined with acid are apparently free from calcareous material, thus 

 differing markedly from the glacial sands of this region, which are com- 

 posed largely of limestone fragments. The sand is also stained a deeper 

 yellow than that associated with glacial drift. 



A well at W. W. Benton's, 1 mile west of Mendon, reached a depth of 

 400 feet, but the water supply is mainly from about 200 feet. The drift 

 penetrated in this well is as follows, the determinations being made by the 

 writer at the time the well was sunk: 



Section of Benton well near Mendon, Illinois. 



Feet. 

 Loess 19 



Gray gummy soil 9 



Yellow sand 



18 



Gray gummy clay, apparently a soil g 



Gray sandy clay with few pebbles 35 



Blue clay with a few pebbles 10 



Total ~85 



On ravines southeast of Mendon the following strata are exposed: 

 Section in a ravine southeast of Mendon. 



Feet. 

 Loess '. 



Black gummy soil-like clay -|_2 



Sand - 5-10 



Gray sandy clay, resembling soil y_.-, 



Brownish clay or clayey sand with pebbles, of variable depth, and underlain by yellow sand, 

 apparently preglacial 20-40 



In the vicinity of Fowler, wells are usually obtained in the drift at 

 depths of 20 to 40 feet, but a well at the mill was sunk to a depth of 262 

 feet and entered rock at 80 feet. 



At Coatsburg, a well at the mill reached a depth of 95 feet without 

 entering rock. The drift is mainly till to a depth of 65 feet, beneath which 

 there is a blue clay with sandy partings which is thought from the descrip- 

 tion to be a water deposit. Waterworks recently constructed at this village 



