310 GEOLOGY OF ILLINOIS. 



places coal No. 1 may not be found; In section 19, township 13, range 2, the 

 rock at the quarries has the appearance of belonging to the conglomerate, at 

 the base of the Measures, which lies below coal No. 1, although No. 2 is found 

 at the bottom of the bluff within about two miles up the creek, and the strata 

 appeared to be nearly horizontal. At some of the mines, the coal from this 

 lower seam is not of the best quality, there being much slaty material with it 

 which requires to be sorted out before it is sent to market. This is not always 

 carefully done, and thereby the value of the coal, and the reputation of the 

 mine is much injured. 



In searching for these lower seams, it is well to know beforehand whether 

 the Coal Measures are present and upon what they rest, though it seems proba- 

 ble that some of the strata belonging to the coal series will be found throughout 

 the county, with, perhaps, the exception, of the bottom lands of the Mississippi. 



None of the underlying strata have been seen in townships 14 and 15, but 

 the coal seam worked along the Edwards, is most likely the lowest one, un- 

 less the lower one found in Richland Grove, township 15, range 1, should 

 prove to be a different seam. This lower seam was recognized with certainty 

 at but two places, about a mile apart, and was reported to be, in each case, 

 about fifteen feet below the seam supposed to be No. 1, and it is not improba- 

 ble that this may prove to be only a lower division of No. 1. In section 1, 

 township 14, range 3, the strata dip as the entry runs back from the mouth 

 of the mine, hence they were obliged to make the drain quite deep, and in dig- 

 ging this they found a broken coal about fifteen feet below the one they work, 

 which is probably the lower division of the seam. 



In township 13, ranges 1 and 2, the Coal Measures may rest, at least along 

 the southern border, upon the Burlington limestone, though it is not certain 

 that this group extends as far north as this, but it is not improbable. Should 

 it be present it will form a horizon readily recognized, below which coal need 

 not be looked for, as the light colored crinoidal, or even the brown arenaceous 

 limestone is very different in appearance from the limestones of the Coal Meas- 

 ures, which are usually dark colored and fine grained. 



From the southern part of Henderson county, where the Burlington lime- 

 stone outcrops, to its most northerly exposure at Bald Bluff, the strata rise 

 gradually. East of here, at the most northerly exposure of the junction of 

 this group with the Kinderhook, in section 35, township 12, range 3, in War- 

 ren county, it is nearly twenty feet above the level of Cedar creek, and proba- 

 bly not less than forty to sixty feet above the Mississippi. At this point the 

 whole of the Burlington rocks appear to be exposed, and do not exceed thirty- 

 five or forty feet in thickness. East of here they are exposed a very little far- 

 ther north, when they disappear beneath the Coal Meaaures. In range 3, the 

 surface of which is considerably lower for some distance than that of ranges 1 



