40 GEOLOGY OF ILLINOIS. 



At Mr. TVarriner's well, a mile and a half northwest of Mr. Plum- 

 mer's, the sandstone was penetrated in a well to the depth of fifty-eight 

 feet without reaching the bottom of the bed, and its entire thickness 

 here cannot be less than from sixty to seventy-five feet. Near its base 

 there is a very hard layer about two feet in thickness, which rings under 

 a blow of the hammer like a compact limestone, probably from a small 

 per cent, of calcareous or ferruginous matter in its composition. A 

 similar hard layer was observed at the base of the sandstone at Hole's 

 quarry, north of Eobinson, in Crawford county, of which this is proba- 

 bly the equivalent. The coal under this sandstone is probably No. 12 

 of the general section, which is somewhat irregular in its development in 

 this county, sometimes affording from eighteen to twenty inches of good 

 coal, while at other places it thins out to a few inches, or is wanting 

 altogether. 



At Mr. Emerich's quarry, two miles and a half north-east of Sumner, 

 a heavy bed of sandstone outcrops on a branch of the Embarras, that 

 is probably referable to this same formation. The face of the quarry 

 shows from eighteen to twenty feet of massive sandstone, presenting a 

 concretionary structure at the base of the bed, but becoming thinner 

 bedded and somewhat shaly towards the top. This rock has been 

 extensively quarried here for building culverts and bridge abutments 

 on the O. and M. railroad. One mile north of the town there has also 

 been a small quarry opened higher up in this formation, where the rock 

 is thin bedded and shaly, but affords some good building stone near 

 the bottom of the quarry, though the overlaying beds are shaly and 

 worthless. 



In the Embarras bluffs near Mr. We H. Miles' place on the N. TV. 

 qr. of sec. 33, T. 5, E. 12, there is a massive sandstone exposed forming 

 the lower portion of the bluff in connection with a thin seam of coal. 

 The section here is as follows : 



Ft. In. 



ilassive sandstone S to 10 



Ferruginous conglomerate 2 to 3 



Coal (probably local) S 



Slope covered to the river level : 10 to 12 



A hundred yards above where this section was seen, the sandstone 

 continues down to the river level with no indications of coal. This is 

 probably the same thin coal found on Brushy creek, near Martin's mill, 

 just over the line in Crawford county, and as it is there from forty-five 

 to fifty feet above the creek level, it indicates a westerly dip of the 

 strata equal to about six or seven feet to the mile. No rocks are known 

 to outcrop on the Embarras for some distance above this point, and 

 below there is no considerable exposure between this and the dam at 

 Lawrenceville. 



Three miles south of Lawrenceville, on Mr. Henderson's place, on 



