80 GEOLOGY OF ILLINOIS. 



completion of the Rock Island and St. Louis railroad to this point. The seam 

 has a good slate and limestone roof, and is underlaid by clay shale and septaria, 

 below which there is a thick bed of argillaceous and sandy shales, passing into 

 sandstone. Following down the creek, which runs northwardly from this point 

 into Crooked creek, the strata are found well exposed down to the horizon of 

 coal No. 3, which lies nearly, or quite, a hundred feet below. At this point, 

 the beds between these coals are more argillaceous than we found them north 

 of Rushville, or in the vicinity of Pleasant View, and showed the following 

 succession of strata, downward from coal No. 4 : 



FEET. 



Fire clay and shale, with septaria 8 to 10 



Clay shale 25 " 30 



Sandy shales , . 30 "40 



Thin bedded concretionary sandstone ; . 8 " 10 



Bluish gray calcareous sandstone 2 " 3 



Clay shale 2 " 3 



Black shale 3 " 4 



Coal No. 3 2 " 3 



The lower coal at this locality, is reported to be 2 feet in thickness, but 

 the opening had been filled up, so that we could not obtain an accurate meas- 

 urement of it at this point. The calcareous sandstone over this coal, contains 

 joints of crinoidea, and the overlying concretionary sandstone contains frag- 

 ments of plants, among which were many broad, ribbon-like leaves of Cordaites. 

 Near Oakland Station, on Sugar creek, ten miles northeast of Rushville, No. 

 3 is found outcropping at several points at the base of the hills. It averages 

 here about three feet in thickness, with a roof of shale and sandstone. The 

 limestone which often intervenes between this seam and No. 2, was seen out- 

 cropping below the coal exposed here, but the underlying coal being below the 

 creek valley, was not seen. 



Northeast of Pleasant View, a good exposure of all the beds, down to the 

 horizon of No. 2 coal, may be seen on the small stream running northwardly 

 into Sugar creek, and the following is the order of succession here, below coal 

 No 4: 



FEET. 



Coal No. 4 4 to 5 



Clay shale and septaria 8 " 10 



Sandstone and shale 116 



Hard bluish gray limestone 8 " 10 



Black shale, with concretions of dark blue limestone 4 " 6 



Blue shale, with streaks of coal (No. 3) 2 " 3 



Sandy and argillaceous shales 56 



Coal ~] 2 



Clay shale I No. 2 coal. 3 



Coal J 2 " 3 



Fire clay and clay shale 20 " 25 



