86 GEOLOGY OF ILLINOIS. 



the same report, is as follows, and is interesting, as showing the variable char- 

 acter of the coals from the same seam at different localities : 



Specific gravity 1.303 



Loss in coking 41.6 



Total weight of coke 58.4 



100.00 



Analysis : Moisture 4.5 



Volatile matters '. 37.1 



Carbon in coke 46.1 



Ashes, (white) 12.3 



100.00 

 Carbon in coal 51.79 



The two lower seams, ranging from two to three feet in thickness, are not so 

 extensively worked at the present time as the one above mentioned, but as 

 they underlie a far greater extent of surface than the upper seam, they will, no 

 doubt, furnish by far the greatest amount of coal in the aggregate. No. 3 is 

 worked by Mr. Spillar, about a mile above Frederick, and affords an excellent 

 coal, containing less of the bi-sulphuret of iron than the coal from the upper 

 seam. No. 2 is often divided by a parting of clay shale, and the divisions are 

 then usually too thin to be worked, but at other localities, it forms a solid seam 

 from too to three feet thick. One or both of these seams will be found under- 

 lying the greater portion of the uplands north and east of Crooked creek, and 

 accessible at many points in the county, remote from the outcrop of the upper 

 seam, and their value and importance will be eventually appreciated, as popu- 

 lation increases, and the demand for coal for mechanical and manufacturing 

 purposes becomes more imperative. 



Clays. Clays suitable for fire brick and for the manufacture of pottery, are 

 usually abundant in the lower portion of the Coal Measures, and the bed 

 of clay shale below coal No. 2, which is used for this purpose at Ripley, in 

 Brown county, is also found here. We found an exposure of it on the place for- 

 merly owned by Mr. James A. Chadsey, on Sugar creek, where it presented 

 the same general appearance as at Ripley, and appeared to be equally well 

 adapted to the manufacture of potter's ware. At the coal bank of McKee and 

 Chadsey, on the head-waters of McKee's creek, north of Rushville, there is a 

 bed of excellent fire clay under the upper coal seam, from four to six feet thick. 

 This may be only a local development, however, as at all the other localities in 

 the county where we saw this under-clay exposed, it partook more of the char- 

 acter of a clay shale, and was also rather too thin to be of any economical value. 

 The fire clay below coal No. 2, is usually of a good quality, and may be profit- 

 ably worked in connection with the coal, when it is two feet or more in thick- 

 ness. Wherever a seam of good fire clay occurs with these lower coals, it will 

 add materially to their value, enabling the miner to drift more economically 

 for both together, than he could do for the coal alone. 



