232 GEOLOGY OF ILLINOIS. 



bluffs, or away from the principal streams, the upper seams may be 

 found more fully developed, and this may be tested at any point in the 

 county where the demand for coal may seem to justify the experiment, 

 by boring down to the Devonian limestones, which will be reached 

 anywhere in the county at a depth probably not exceeding 300 feet. 



About seven miles below Andalusia, and in the neighborhood of Illi- 

 nois City, coal is worked by a Mr. Arnold, by drifting into the Mississippi 

 river bluffs. Here the seam is almost four feet thick, and the quality of 

 coal about same as at the mine worked by Mr. Smith, east of Andalusia. 

 On Copperas creek, in township 16, range 5, the same seam, I think, is 

 reached by a shaft of moderate depth. 



The Coal Valley mines have been worked for many years and have 

 made their present proprietors wealthy. Some ten years ago a railroad 

 was built from Coal Valley to Bock Island city, with depots and all the 

 appurtenances of a first class road. A village of eighteen hundred in- 

 habitants has sprung up round the mines. From sixty to one hundred 

 miners find constant employment, and two hundred and fifty tons p*r day 

 are sent to Rock Island when the mines are worked with the latter 

 number of hands. This coal is sent into Iowa and Northern Illinois, but 

 is used principally for making steam on the Mississippi river, for which 

 purpose it seems well adapted. The working of these mines, the trans- 

 portation, of the coal to the river, and the capital or ownership of the 

 mines, is all under a sort of a triune arrangement, which, under the en- 

 ergetic supervision of the Messrs Cable, seems to work admirably. The 

 coal company, the railroad company, and the miners each receive one- 

 third of the coal mined, or profits realized. A perfect community of in- 

 terest is thus kept up, and strikes and dissatisfaction are comparatively 

 unknown. 



The coal seam is from four to four and a half feet thick. It is sub- 

 ject to local dips and elevations, sometimes dipping below the water 

 level. Faults or "horsebacks" are struck when the drifts extend far 

 into the hills. Beyond these so-called faults, sometimes only black shales 

 are found, and sometimes the coal seam becomes too thin to work. The 

 roof is composed of black shales, in places rotten, and is succeeded by 

 dark, irregularly -bedded limestone, of slaty cleavage and conchoidal 

 fracture. In one or two instances, for short distances the seam is 

 double, being separated by several feet of dark shales and other foreign 

 matter. The floor of the seam sometimes consists of an impure fire-clay, 

 and in other places of a black slate, with some resemblance to canuel 

 coal. Wooden railways are laid in the drifts, and the coal is hauled out 

 by mules and wooden cars, and dumped directly into the railroad cars 

 at the station. Some of the hills are tunneled pretty thoroughly, and 

 the supply of coal well nigh exhausted in them, but new drifts, and far- 



