322 GEOLOGY OF ILLINOIS. 



FEET. IN. 



7. Clay shale 1 



8. Black slate 3 6 



3. Coal No. 1, about 3 



None of the mines in either seam were open when I was at this place, and 

 hence I was unable to measure the coal accurately. It seems probable that 

 this coal, and also No. 2, underlies nearly, if not the whole, of Knox county. 



While the strata of the Coal Measures dip, locally, in almost every direction, 

 they appear to have a general inclination to the southeast, save, perhaps, in the 

 northwestern part of the county, and here I do not know the direction. The 

 dip, however, is not regular, but seems to be quite undulating. 



Coal No. 2 first outcrops in the bed of Walnut creek, in section 17, town- 

 ship 12, range 5, in Stark county. South of this it is not again exposed, as far 

 as I learned, between that point and section 14, township 11, range 4, in Knox 

 county. From this point, Spoon river, with its various windings, runs to the 

 west for about five miles, and then south about nine miles, from whence it 

 passes to the southwest till it leaves the county. From where this coal first 

 appears in Knox county, it is occasionally exposed along the river and near its 

 bed to a point a little beyond where the river turns south. In the northwest 

 quarter of section 6, township 10, range 4, it lies low in the bed of the river, 

 and is frequently torn up in considerable quantities by the current at high 

 water, and is sometimes worked when the river is very low. Some two or 

 three miles south, near the bridge, it appears a little above the bed of the river. 

 At Burnett's mill, section 34, township 10, range 3, the coal lies some ten or 

 more feet above the river level, but southwest of this, in section 10, township 



9. range 3, it is worked in the bed of the river. In sections 26 and 27, town- 

 ship 9, it again appears, but how much above the bed of the river I did not 

 learn. A mile and a-half west of this it crops out along a branch of Spoon 

 river, about fifteen feet above its bed. South of here, this coal is not worked 

 along the river in this county, as far as I could learn. 



Economical Geology. 



Stone for Building, Knox county has but a limited supply of good build- 

 ing stone. Some portions, however, have sufficient for their own wants. 

 North of Knoxville, in the western half of sections 16 and 21, township 11, 

 range 2, quarries have been opened in a heavy sandstone bed. Some portions 

 of the rock do not appear to be of much value, while others, though soft, form 

 a durable material for the use of the builder. This rock appears to lie above 

 coal No. 2, and is probably the equivalent of a similar bed, in this position, in 

 Mercer county. In the northeast quarter of section 16, there is a quarry that 

 affords an entirely different rock. It is a dark drab-colored conglomerate j 



