772 



THE ILLINOIS GLACIAL LOBE. 



In the spring of 1897 a boring was begun at St. Johns by the Illinois 

 ( !entral Coal and Salt Company which at last reports had reached a depth 

 of more than 3,600 feet, and the drilling was still in progress. So far as 

 the writer is aware, it is not exceeded in depth by any other boring in 

 Illinois. The detailed record to a depth of 2,275 feet, which is given 

 below, was furnished by John Forester, superintendent of the company, in 

 July, 1898. Since then Mr. Forester has communicated the general results 

 from time to time. A limestone formation forms the lower part of the sec- 

 tion below the point where the detailed record ends. Mr. Forester states 

 that a good quality of fresh water was found at a depth of 311 feet, but in 

 such limited quantity that it was soon exhausted by a pump of 15-gallon per 

 minute capacity. At 520 feet water was encountered which showed 15 per 

 cent salt. Below this depth the salinity gradually increased until at 980 

 feet it reached 34 per cent. This water was cased out at 1,000 feet, and 

 very little more was encountered until a depth of 1,604 feet was reached, 

 when a vein of water with 38 per cent salt was struck. The well continued 

 to yield this water until a bed of "fire clay" was reached at 1,949- feet. 

 After passing through 20 feet of fire clay another yield of water with 38 per 

 cent salt was found, which continued to a bed of shale at 2,026 feet. No 

 more water was found until a depth of 2,271 feet was reached, when a 

 vein of the same salinity was struck. At this depth there was apparently a 

 crevice in the rock lined with crystals of calcite. As yet no identifications 

 of the geological formations have been made. Temperature tests were 

 made by Mr. Forester in March, 1899, when the boring had reached a depth 

 of 3,600 feet. After an exposure of two hours the thermometer registered 

 93° F., and after an exposure of twenty-four hours 101° F. 



Log of deep boring at St. Johns, Illinois. 



Glacial drift... 



Lime rock 



Sandy shale . . 

 Shale and coal 

 Sandy shale . . 



Clay shale 



Sandy shale . 

 Sand rock 



Feet. 

 42 

 3 

 16 

 10 

 25 

 30 



Sandy shale 



Fire flay and shale 



Shale with partings 



Sand rock, fresh water 



Lime rock 



Sand rock, 15 per ceut salt 



Sandy shale 



Sand rock 



23 

 12 

 55 

 178 

 31 

 15 

 28 

 15 



Feet. 



221- 244 

 244- 256 

 256- 311 

 311- 489 

 489- 520 

 520- 535 

 535- 563 

 563- 578 



