66 GEOLOGY OF ILLINOIS. 



FEET. 



Sandstone and sandy shale 15 to 20 



Blue argillaceous shales 30 " 40 



Shaly calcareous sandstone, with fossils 3 " 4 



Argillaceous, or bituminous shale 8 " 10 



Coal No. 2 H" 2 



Fire clay 2 " 3 



This lower coal seam is worked at several points northeast of Mount Sterling, 

 in open trenches, along its outcrop, in the valleys of the small streams. Four 

 miles northeast of that point, it is worked in this way by Mr. Miller, on a 

 branch of Curry creek. The coal is about two feet in thickness, and of good 

 quality, with about five feet of clay shale in the roof, above which there is a 

 bed of black shale, that, at some other localities in this vicinity, rests directly 

 upon the coal. Two miles north of Mount Sterling, a shaft was sunk by Mr. 

 Graves to the depth of about ninety feet, when he struck the coal worked in 

 this vicinity at that depth. The seam was found to be from 28 to 30 inches 

 thick, which was not deemed sufficient to assure a paying investment in coal 

 mining at this point, and the shaft was subsequently abandoned. Another 

 shaft was sunk near Mound Station, with a similar result. 



On Little Missouri creek, in the northwest corner of the county, on section 

 7, township 1 north, range 4 west, coal is dug at many points in the ravines 

 which intersect the bluffs of the main creek. The coal ranges in thickness 

 here from 24 to 30 inches, and is overlaid by clay shale, containing plants, and 

 otherwise presents the usual characteristics of No. 2 coal. A section of the 

 strata exposed in this vicinity, shows the following order of succession : 



FEET. 



Sandy shales 8 to 10 



Evenly bedded sandstone " 8 



Black shale " 3 



Limestone * " 4 



Clay shale . 25 " 30 



Coal 2 " 2 



The black shale in this section may represent the horizon of coal No. 

 3, and if so, then the thin seam near Mount Sterling, which we have 

 marked No. 3, with a query, is probably a local development. This seems most 

 probable, as it presents none of the usual features of either No 3 or 4, and we 

 have seen no other outcrop of coal, either in this or the adjoining counties, 

 that we can identify with this. If it represents No. 3, there is a great thicken- 

 ing of the strata at this point, for this coal is not usually more than forty or 

 fifty feet above No. 2, whereas, in the section near Moujjt Sterling, the thick- 

 ness of the intervening strata is from seventy-five to one hundred feet. 



At the La Grange bluff, on section 29, township 1 south, range 1 west, the 

 lower part of the Coal Measures are well exposed, resting upon the St. Louis 



