770 THE ILLINOIS GLACIAL LOBE. 



WASHINGTON COUNTY. 

 GENERAL STATEMENT. 



Washington County is situated northeast of Randolph and east of 

 St. Clair County, with Nashville as the county seat, and has an area 

 of 540 square miles. The Kaskaskia River forms a portion of the north 

 border and receives the drainage of the greater part of the county. The 

 southeast part of the county drains southward through Beaucoup Creek, 

 a tributary of the Big Muddy River. The uplands are coated with 

 white clay scarcely as compact as that which is found in counties north 

 and east. 



The drift masks the preglacial ridges and hills without entirely 

 concealing them. The drainage lines are probably in large part aloug 

 preglacial courses, but at levels above the old rock floor On the uplands 

 or preglacial ridges the drift is only 10 or 20 feet in depth, but along the 

 main preglacial valleys it probably exceeds 100 feet. Wells usually enter 

 rock a few feet on the uplands, but on the lowlands and along valleys they 

 obtain water from the drift. The depth rarely exceeds 40 feet. 



INDIVIDUAL AVELLS. 



At Nashville the wells range in depth from 14 to 45 feet and usu- 

 allv enter rock a few feet. The strongest ones are estimated to have 

 a capacity of 100 barrels a day, but many will yield not more than 10 

 barrels. 



In the vicinity of Hoyleton the drift is 15 to 30 feet in depth and 

 many wells are sunk into the underlying rock, obtaining water at about 40 

 feet. They are largely through till of brownish yellow color. 



In the vicinity of Ashley wells range in depth from 8 feet to about 

 40 feet. Rock is entered at 15 or 20 feet, and the drift is mainly a 

 brown till. 



In the southern part of the county the distance to rock is usually but 

 12 to 20 feet and wells not infrequently penetrate it a few feet, A few 

 knolls southwest of Oakdale appear to have no rock nucleus, but informa- 

 tion concerning them is unsatisfactory. 



In the northwest part of the county, on the borders of the Kaskaskia, 

 wells are obtained without entering rock, at depths of 20 or 30 feet, 



