590 THE ILLINOIS GLACIAL LOBE. 



depth of 163 feet, or about 100 feet below the level of Lake Michigan. 

 The well record indicates a soft till extending from the surface to a depth 

 of 86 feet, beneath which there is a harder material called shale, but perhaps 

 a till, 77 feet in depth. Another well in Morgan Park is reported to have 

 struck limestone at a depth of only 90 feet. 



At Riverdale rock is entered at about 45 feet, at Dolton at 35 or 40 

 feet, and in the vicinity of Harvey at 20 or 25 feet. The public water 

 supply at Harvey is obtained from deep wells, one of which derives its 

 water from the St. Peter at 1,300 feet and another terminates in Potsdam at 

 2,075 feet. 



At Blue Island wells usually reach water in sand, connected with the 

 lake occupancy, at a depth of about 25 feet. 



On "Lanes Island," in the Sag' outlet, several wells reach a depth of 

 30 feet without entering rock. After penetrating 4 to 8 feet of sand they 

 are mainly through till. 



At the village of Worth wells usually obtain water at about 16 feet 

 in sand below till. Rock is exposed along the Sag outlet in that vicinity at 

 about the level of Lake Michigan. A well 4 miles east of Worth, in sec. 

 23, T. 27, R. 13 E., reaches rock at 55 feet. The drift is mainly till. 



On the island-like tract of moraine between the Sag outlet and Des 

 Plaines, northwest of Worth, several wells reach a depth of about 80 feet 

 without entering rock. They are mainly through blue till. 



On the Valparaiso moraine, in the south part of Cook County near 

 Alpine, several wells have a depth of 80 feet without entering rock. Small 

 amounts of inflammable gas have been found in some of these wells. 



In the vicinity of Matteson and northward in T. 35, R. 13 E., wells 

 frequently reach depths of 50 to 65 feet without entering rock. In the 

 vicinity of New Bremen, in T. 36, R. 13 E., the wells are frequently 75 

 feet in depth and obtain water in gravel beneath the till. 



In the vicinity of Grlenwood wells along the beach penetrate 8 to 12 

 feet of gravel before entering till, and strike rock at about 30 or 35 feet. 



A flowing well was obtained by Mr. Winterhoffe on his farm in sec. 6, 

 T. 35, R. 15 E., at a depth of 75 feet without reaching rock. It was through 

 till the entire depth. A neighboring- well at Lewis Peter's enters rock at 85 

 feet, but the water level is 14 feet below the surface. Another well, in sec. 

 12, T. 35, R. 14 E., strikes rock at 85 feet and there obtains water, which 



