306 GEOLOGY OF ILLINOIS. 



thin layers, from two to eight inches in thickness. The large slabs that form 

 the roof and floor of the cells of the Aledo jail, were taken from section 4, and 

 some of the thicker layers were used for the walls of the cells. 



The blue limestone, No. 2 of the section, is of little or no value for building 

 stone, as it falls to pieces on being exposed to the weather a short time. It is 

 sometimes burned for lime. 



Large quantities of the gray or drab colored limestone are taken from the 

 quarries of H. Boone, Esq., in section 34, township 15, range 2. The coal, 

 No. 3 of the last section, is also worked here. 



From the mines in section 19, township 15, range 3, and sections 23 and 24, 

 township 15, range 4, the following section was obtained : 



FEET. 



1. Sandstone. Not measured 



2. Limestone 2 to 4 



3. Black slate 1 to 8 



4. Coal 3 



5. Clay shale. Not measured 



The black slate, No. 3 of this section, in some cases attains a local thickness 

 that was not noticed elsewhere in this county. A number of mines have been 

 worked in section 34, township 15, range 4. In section 12, township 14, range 

 4, there is a coal shaft near the Edwards river. The following section, obtained 

 in part from the slope above, and in part from the shaft, was furnished me by 

 the proprietor of the shaft, B. C. Taliaferro, Esq., of Keithsburg : 



FT. FT. IN. 



1. CoaINo.2 1 to 1 6 



2. Slope 12 to 15 



3. Clay, very hard and compact 4 



4. Quicksand or decomposed sandstone 3 



5. Clay shale, very hard 23 



6. Coal No. 1 3 6 



7. Impure coal, or slate 6 



8. White clay. Not measured 



The coal obtained from this mine is reported to be of good quality. A layer 

 of sandstone in section 8 has furnished considerable building stone, but no 

 work appears to have been done here for sonic time. 



From the mines in sections 20 and 21, township 15, range 1, the following 

 section was obtained : 



FT. IN. FT. 



1. Sandstone 4 to 6 



2. Limestone 1 to 21 



3. Coal No. 1 3 to 4 



4. Sandy clay shale 8 



5. Limestone 6 to 8 



6. Coal.. .1 6 to 6 



