686 THE ILLINOIS GLACIAL LOBE. 



depth. The deep well penetrates 145 feet, but in parts of the city at 

 similar altitude rock is entered at only 60 feet. 



At Adair the wells are usually 25 or 30 feet in. depth, though they 

 occasionally pass into the rock, which is entered at about 50 feet. The drift 

 is mainly blue till, which is entered at only 10 or 12 feet from the surface. 



At Good Hope the village well is 33 feet in depth and has the follow- 

 ing section, reported by Rev. S. D. Peet: 



Section of town well at Good Hope, Illinois. 



Feet. 



Loess 16 



Pebbly brown clay 2 or 3 



Saud with a few pebbles 9 



Fine sand with ferruginous crust 2 



Blue saud 2 



Blue till 2 



Wells in the vicinity of Grood Hope enter rock at depths ranging from 

 45 to 86 feet, and are mainly through blue till. 



FULTON COUNTY. 

 GENERAL STATEMENT. 



Fulton County is situated east of McDonough and has the Illinois 

 River on its eastern border. The area is 870 square miles, and Lewistown 

 is its county seat. The principal stream traversing the county is Spoon 

 River, which passes in a southward course through its western part. The 

 surface, like that of the adjoining counties on the north and west, is well 

 drained. In addition to the drainage lines, which carry off much of the sur- 

 plus rainfall, there is a capping of porous loess which absorbs a large part of 

 the rain and returns the water to the soil in seasons of drought. 



The drift is in thickness similar to that in adjoining counties. An 

 average of sections on the uplands reaching rock is 41 feet. In preglacial 

 valleys the thickness is much greater, for the main valleys were cut to a 

 level 75 feet or more below the low water of the present Illinois. The 

 majority of wells are obtained without entering the rock, there being a 

 sufficient amount of sand and gravel interbedded with the till to afford 

 a strong supply of water for wells. 



INDIVIDUAL WELLS. 



At Farmington, in the northeast corner of the county, the drift is only 

 about 20 feet in thickness and wells are frequently sunk to slight depth in 



