6 ECONOMICAL GEOLOGY. 



Ft. In. 



Shale 15 



Hard sandstone 5 



Shulo S 5 



Coal ! 



Slato and shale 6a 



358 



Only two thin seams of coal were found here below No. 5, neither 

 of which were thick enough to be of any practical value. No. 1, which 

 at Seville, about sixteen miles west of Canton, is three feet thick, was 

 only one foot at Canton, and it is also about the same at its out- 

 crop in the bluffs of Spoon river, south of Lewistown. 



Coal No. 5, or the Springfield coal, as it is sometimes called, is 

 perhaps the most reliable and persistent seam in its development of 

 any in the State. Its average thickness is about six feet, and its 

 range from four to eight. From Bloomington to Carlinville, along 

 the line of the St. Louis, Alton and Chicago railroad, it has been 

 found at every point where a boring or shaft has been carried down 

 to the proper depth; and recently a shaft has been sunk to it at 

 Decatur, where it was found at a depth of about six hundred feet. 

 At Sandoval and Centralia, a seam averaging about the same in 

 thickness, is found at about the same depth, which may be the 

 equivalent of the Springfield coal. At all these points the seam is 

 about six feet in thickness, and it probably affords at this time more 

 than one-half of the entire coal product of the State. There are 

 now seven coal shafts in operation on this seam within two miles 

 of the State capital, and nearly as many more within the limits of 

 Sangamon county. The roof is usually composed of a hard black 

 slate overlaid by a few feet of argillaceous limestone, the former 

 containing numerous fossil shells, by which it may usually be 

 readily identified. 



Coal No. 6 is mined at several localities in Fulton and Peoria 

 counties, where it ranges from four to five feet in thickness. It af- 

 fords a coal somewhat softer than that from No. 5, but freer, from 

 sulphur, and therefore better adapted for forging iron. The seam is 

 more irregular in its development than No. 5, and consequently is 

 neglected except when a superior quality of coal is required for the 

 smith's forge, or some other special use. In the shafts in Sang;i- 

 mon county, it ranges from a few inches to three feet in thickness, 

 but no attempt has been made to work it in any of those in opera- 

 tion at the present time. 



