TAZEWELL, Me LEAN, LOGAN AND MASON COUNTIES. 181 



The coal seain which is worked in this immediate neighborhood, is No. 4, as 

 has been already stated. A good exposure "of this coal may be seen near the 

 track of the Toledo, Peoria and Warsaw railroad, at the point of the bluff where 

 the road enters the valley of Farm creek. It is here immediately overlaid by 

 the Loess and Drift, and is about four feet in thickness, the same as its average 

 in other localities thereabouts. It is worked in various places, both in the river 

 bluffs and for a mile or more up the valley of Farm creek, by horizontal drifts 

 into the hill sides, some of which, in their various branches, are of considerable 

 linear extent. The beds overlying the coal are not exposed at the surface at 

 any point north of Farm creek, but the seam is generally found to have a roof 

 of sandstone or sandy shale in the interior portions of the drifts. South of the 

 creek, however, this sandstone is exposed in many places up the side ravines, 

 and in R. A. McClelland & Co.'s shaft, in the center of the southern part of 

 section 34, township 26, range 4, it was found to be twenty-eight feet in thick- 

 ness between the coal and the overlying drift clay and gravel. This, however, 

 is by no means to be taken as its full average thickness, as at this point it has 

 probably lost much of the upper portion of the bed by denudation. 



Passing up a small branch, which comes down through the bluffs from the 

 southward, just back of the village of Fond du Lac about half a mile, I ob- 

 served a striking exposure of about twenty-five feet in vertical thickness of con- 

 cretionary sandstone, sandy shales, and soft argillaceous sand-rock, which be- 

 long to these same sandy strata overlying the lower bed of coal. The more 

 shaly beds contained numerous iron-stone concretions, and I observed in the 

 more massive portions, what appeared to be indistinct vegetable impressions, 

 but no other fossils. About half a mile or a little more, still farther up the 

 ravine, the upper vein of coal has been worked to a very slight extent. In 

 actual position, it must be, at this point, at least seventy feet above the coal 

 No. 4, and is possibly still more than that. It is here reported to be about 

 three feet in thickness, and is overlaid by about two feet of grayish, fossilifer- 

 ous limestone, with occasionally an intermediate layer of black slate just over 

 the coal, and forming its roof. Still another seam of coal about fifteen inches 

 in thickness, is said to outcrop farther up the hollow, but after a careful search 

 I was unable to discover its outcrop, and concluded that it must have been cov- 

 ered by the sliding of the drift gravel, etc., from the bluffs above. 



Along the Illinois river bluffs, between Fond duLac and Wesley City, there 

 are several points where coal is now, or has been worked, and there are a few 

 exposures of the overlying sandstones, in the bluffs near the main wagon road. 

 South of Wesley City, there are scarcely any exposures on the river face of the 

 bluffs, but up the side ravines they are more numerous. In one of these ra- 

 vines some distance from the road, on the land of Mr. Davis, I observed the 



