328 GEOLOGY OF ILLINOIS. 



Along a little branch that enters Spoon river, near the north line of section 14, 

 this seam outcrops some ten or more feet above the stream. The exposure in 

 this locality gave the following succession of strata : 



FT. IN. FT. IN. 



1. Sandstone. Not measured 



2. Clay shale 12 to 15 



3. Impure limestone 1 to 2 



4. Clay shale 1 6 



5. Black slate 6 



6. Coal 2 to 4 



1. Clay, parting 2 to 3 



8. Coal 1 6 to 2 



9. Clay or clay shale 3 to 4 



10. Sandstone. Not fully exposed 



The black slate over the coal contains numerous fossils, but mostly imper- 

 fectly preserved. Among those obtained^are, Cardlnia fragilis? Avicidopecten 

 rectalaterarea, Discina nitida, Pleurotomaria Grayvillemis, together with some 

 fish remains. 



No. 10 of this section is worked for building stone, and affords a fair article 

 The coal, and also the other strata for some distance above and below it, are 

 well exposed in the bluff. 



From this point, along the river and on the little runs that put into it, the 

 coal has been more or less worked, until we reach sections 25 and 26, where the 

 seam lies some twenty feet or more above the river. In section 26, on the level 

 land and a little back from the river, several shafts have been sunk. One of 

 the most westerly of these gave this section : 



FEET. IN. 



1 . Soil and Drift 20 



2. "Second soil," black and very soft 10 



3. Clay 4 



4. Limestone 2 to 5 



5. Sandstone 12 



6. Clay shale 15 



7. Limestone, containing much pyrite 1 8 



8. Blackslate 1 6 



9. Coal 4 to 5 



10. Clay. 6 



11. Sandstone, exposed 15 



A short distance to the east of this, and from about the same level, it was 

 found necessary, in sinking a shaft, to go about thirty feet deeper in order to 

 reach this seam. South of here, this coal is worked in section 23, township 



12. range 6, when it appears in the bluff some eight or ten feet above the river. 

 It is thinner here than at the other mines in the county, and the overlying 



