WELLS OF HENDERSON COUNTY, ILLINOJS. 679 



In the southeast part of the county rock is often struck on the high 

 points at 25 feet or less, but on lower ground the drift is usually thicker. 

 In the southwest part of the county the drift appears to have an average 

 depth of at least 50 feet, and wells seldom reach the rock. 



The Manual of American Waterworks (1897) reports that waterworks 

 systems have recently been introduced at Alexis, Kirkwood, and Roseville. 

 In each village the supply is from a well. That at Kirkwood is reported 

 to be insufficient for the needs of the village. 



HENDERSON COUNTY. 

 GENERAL STATEMENT. 



Henderson County borders the Mississippi River in the western part 

 of the State, immediately west of Warren and south of Mercer County. 

 It has an area of 380 square miles, and Oquawka is the county seat. The 

 county is drained mainly by Henderson River and its tributaries, which 

 lead westward to the Mississippi. The southern portion is tributary to 

 Honey Creek, which leads westward entirely across the county. 



There is a strip of the Mississippi bottoms along the west border of the 

 county having an average width of about 5 miles, much of which is subject 

 to overflow and is sparsely settled. The remainder of the bottom land is 

 very sandy. The uplands, which stand about 200 feet above the river, are 

 covered with loess to a depth of 20 feet or more. In places the loess has 

 been heaped into dunes and ridges on the brow of the bluffs, which stand 

 50 feet or more above the uplands to the east. In places also sand in 

 dunes appears along" the brow of the bluff. 



But few records of wells have been obtained in this county, and these 

 indicate considerable difference in the distance to rock, there being a range 

 from 20 feet to over 150 feet. The rock floor of the Mississippi Valley 

 probably stands nearly 150 feet below the level of the bottoms, its elevation 

 at Fort Madison, Iowa, just beyond the limits of this county, being 360 to 

 370 feet above tide, or about 140 feet below the level of low water at that 

 city. Preglacial tributaries of this valley would be excavated to a corre- 

 spondingly low level; hence we may expect to find a drift filling of not less 

 than 300 feet on the portions of the uplands adjacent to the Mississippi, 

 where the valleys have been filled to the level of the upland plain. 



