WELLS OP LAKE AND COOK COUNTIES, ILLINOIS. 581 



Near Lake Zurich, in the southwestern part of the county, a few wells 

 have been sunk to depths of over 200 feet without entering- rock. One in 

 the village of Lake Zurich reached a depth of 240 feet; one on the Fletcher 

 farm in sec. 32, a depth of 230 feet, and one about a mile east of the village 

 reached a depth of 297 feet. The latter has the following section : 



Section of well near Lake Zurich, Illinois. 



Feet. 



Yellow till 12 



Blue till 88 



Fine sand 197 



Total 297 



Gravel at bottom. 



A well driller states that much sand is found at depths of 100 feet or 

 more beneath the crest of the Valparaiso moraine in the vicinity of Lake 

 Zurich. 



At Barrington, on the south line of the county, two wells enter rock 

 at 254 and 258 feet, respectively. The}- encounter considerable coarse 

 gravel and cobble at about 160 feet The remainder of the section is mainly 

 till. It is thought that this cobble bed occupies the junction between the 

 Wisconsin and earlier sheets of drift, there being a change to a harder till 

 beneath it. 



At Hainesville, in the north central part of the county, good wells are 

 usually obtained at 80 or 90 feet, but one boring' is reported to have reached 

 a depth of 287 feet without obtaining water or entering rock. Another 

 unsuccessful boring is reported to have been made at Gilmer, in the south 

 central part of the county. It reached a depth of 213 feet without entering 

 rock. At Deans Corners rock was struck at 290 feet. At Ravinia, in the 

 southeast corner of the county, a well 186 feet in depth entered rock at 

 164 feet. 



COOK COUNTY. 

 GENERAL STATEMENT. 



Cook County, of which Chicago is the county seat, has a wide frontage 

 on Lake Michigan and extends back to distances of 15 to 30 miles from 

 the lake, there being much irregularity in the western border. It is one of 

 the largest counties of the State, the area being 960 square miles. The 

 Chicago River, whose main branch heads near the north line, flows south- 

 ward near the eastern edge of the county and enters the lake through the 



