WILL COUNTY. 211 



Plaines, below this point, the sandstone lies partly upon the bottom beds of the 

 Niagara limestone, partly upon the green shales at the top of the Cincinnati 

 group. It here contains some remains of trees, one of which, forty or fifty 

 feet long, has been mentioned by Schoonmaker as a tree of " black walnut," 

 vhich in color it very much resembles. 



Above the feeder dam pn the Kankakee, coal is said to have been found in 

 /he bed of the river opposite the mouth of Prairie creek; but, at Mr. Mellai's 

 place on the opposite bank, the bluff is composed of dark colored shales, partly 

 sandy, partly calcareous, belonging to the Cincinnati group, between which 

 and the Niagara limestone quarried on the other bank, there is certainly no 

 place for any regular deposit of coal. 



As I have been unable to connect the foregoing section with any outcrop 

 whose position" is known, and in the absence of characteristic fossils, I cannot de- 

 termine with certainty, its relation to the other Coal Measure rocks of this 

 county; but it probably belongs below them, and its equivalent should be 

 found by boring below the level of the main seam at points further south. 

 However, as the seam is so variable within the small space over which we have 

 recognized it, there would be no certainty, in fact, very little probability, of its 

 yielding any paying quantity of coal at any given locality. I cannot, there- 

 fore, encourage the hopes which some persons entertain, of finding another 

 seam of coal, by boring in the bottom of the present workings, while, at the 

 same time, I would not deny the possibility of finding such. 



On the other hand, as I believe that no borings have been made on the west 

 side of this mine, between it and the strippings southeast of Goose lake, the 

 coal at which latter point unquestionably belongs to the main seam, although 

 its characters are very unusual, I cannot assert that this is not also a continu- 

 ation of the same seam, which owes its irregularities to its position upon the 

 extreme border of the basin. 



The southwest corner of this county is full of shafts, varying from twenty 

 to seventy feet in depth, by which the main seam of coal is reached, and from 

 which, hundreds of thousands of tons of coal are annually sent to market. 



This seam varies from two feet ten inches to four feet in thickness, and pos- 

 sesses various characters, according to location. Some portions yield a very 

 pure coal, fit for blacksmith ing, while others yield a very impure article, con- 

 taining much pyrite and flakes of calcite. Some parts contain these impurities 

 disseminated in small particles through the whole mass ; and in others we find 

 them concentrated in certain benches of the seam, or even compacted into one 

 or more thin bands which can readily be removed in mining. As a whole, this 

 seam yields a good coal for steam purposes. 



