84 GEOLOGY OF ILLINOIS. 



Feet. 



Space unexposed 15 to 20 



Hard sha'y sandstone in the bank of Skillet Fork 3 to 4 



Hard, black laminated slate, passing locally into clay shale 6 to 8 



Shale, with a thin coal 2 to 3 



Hard, fine-grained limestone, without fossils 2 to 3 



Greenish, pebbly shale 2 



Sandy shale 1 



The three upper beds in the foregoing section are found in Wayne 

 county about three-quarters of a mile north-east of the village. Prof. 

 Cox reports a section six miles south-east of Fairfield, which seems to 

 be nearly a repetition of that at Mill Shoals, as follows : 



Ft. 



" Yellow clay and drift 15 



Sandstone and locally some shale 45 



Gray silicious shale 10 



Thin coal _ \ — 



Limestone, without fossils 2 " 



These two sections will give a general idea of the prevailing character 

 of the rocks in the south part of Wayne county. The following is a 

 section of a well bored for oil by Major Collins on sec. 25, T. 2, E. 7 : 



Ft. In. 



Soil and subsoil 3 



Sandstone - 50 



Slate— (shale ?) 27 



Coal 3 6 



Clay and blue shale 2 



Hard gritty rock 4 



Hard yellow rock- 4 



Hard sandstone.. 8 to 10 



Dark slate— (shale?) 28 



White sandstone 66 



Black shale 4 6 



307 



It is proper to state here again what we have already said on more 

 than one occasion, that reports of oil wells are to be taken with due 

 allowance, in consideration of the fact that the persons having the 

 work in charge were seldom qualified to determine tlie true character 

 of the beds through which their drill was passing, and we see in the 

 above section that no attempt was made to define the character of two 

 beds of hard rock, while the beds denominated slate were probably 

 shale, with possibly a thin bed of slate intercalated therein. In this 

 way bituminous slate is often mistaken for coal, and where, the sub- 

 stance is reduced to an impalpable powder by the drill no one but an 

 expert can fully determine the one from the other by the material 

 brought up in the sand pump. 



At Mr. Black's place, about two miles north-west of Fairfield, there 

 is an outcrop of hard, dark, bluish-gray limestone, weathering to a buff 

 color, which is overlaid by clay shale, with a thin coal or bituminous 

 shale intercalated therein, as indicated by a streak of smutty material 

 to be seen a few feet above the limestone. A thin coal, sometimes as 



