CALHOUN COUNTY. 21 



granite, sienite, and other metarnorphic and igneous rocks, have been trans- 

 ported from localities hundreds of miles to the northward, would also account 

 for the occurrence in the drift material in which they are imbedded, of any 

 other mineral or rock that is known to occur in the direction from which the 

 great mass of the drift material has come. 



Iron, both in the form of a carbonate and of a sulphuret, occurs in the Coal 

 Measures in this county. The carbonate is most commonly met with in the 

 form of nodules or " kidney ore," in the shales associated with the coal, while 

 the sulphuret occurs in the coal itself, as well as in the shales, in yellow or sil- 

 very gray crystals, and often forming nodular concretions of considerable size. 

 The sulphuret is worthless as an ore of iron, and is only useful when it occurs 

 in large quantities, for the manufacture of copperas and alum, both of which 

 may be obtained from it. The carbonate is a valuable ore for the production of 

 metalic iron, whenever it can be found in sufficient quantity to justify the 

 establishment of a furnace. The shales forming the roof of Williams's coal, 

 are highly ferruginous, and there is about a foot in thickness of impure iron ore 

 between the main coal seam and the thin, four-inch seam above it, at the only 

 locality where we found an exposure of the shales forming the roof of this coal. 

 Nodules of the carbonate of iron "were also seen at other points, which had, no 

 doubt, come from the shales of the Coal Measures, but we met with no body 

 of iron ore in this county, where it seemed to be in sufficient quantity to be- 

 come valuable for the production of iron. 



Coal. Although there is a development of about one hundred and twenty 

 feet in thickness of strata belonging to the Coal Measures, in this county, in- 

 cluding the horizon, of at least three seams of coal, only one has yet been found 

 thick enough to pay for working. This seam has been partially opened at sev- 

 eral points in the county, but no systematic mining seems to have been 

 attempted, except at Williams's mine, situated in the bluffs of the Mississippi 

 river, about a mile above Fruitland Landing. The coal is here about twenty- 

 six inches thick, of good quality, and apparently quite free from the sulphuret 

 of iron. An analysis of this coal, by Mr. Henry Patten, reported in Norwood's 

 "Analysis of Illinois Coals," gave the following results: 



Specific gravity 1.2631 



Loss in coking 45.7 



Total weight of coke 54.3 



100.00 



Analysis: Moisture 4.8 



Volatile matters 40.9 



Carbon in coke 49.1 



Ashes (brown) 5.2 



100.00 



Carbon in coal 53.06 



Without a more complete exposure of the strata, and in the absence of fossils, 

 both animal and vegetable, in connection with this coal seam, it is difficult to 



