PIKE COUNTY, 35 



worked by "stripping." The seam at Mr. Huntley's, near the north line of 

 the county is, however, an exception, and may be worked to good advantage 

 by any of the ordinary modes of mining. It is probable, however, from the 

 general development of the coal, both in Pike and Adams counties, that the 

 unusual thickness of the seani or seams, at this point, is a merely local phenome- 

 non, and will be found to extend over only a small surface area. Local thick- 

 enings of this kind are not uncommon, and are denominated" pockets" by the 

 miners, the coal sometimes thickening to twelve or fourteen feet, and yet cov- 

 ering only an acre or two of surface, thinning out entirely in a few rods in 

 either direction. 



Quaternary System. A broad belt of alluvial bottom lands, from six to 

 twelve miles in width, skirts the western border of this county, through its 

 whole extent from north to south. The soil on these lands is exceedingly fer- 

 tile, and where they are elevated above the annual overflow of the river, they 

 comprise some of the most valuable and productive lands in the county. Belts 

 of heavily timbered lands skirt the small streams that intersect these alluvial 

 bottoms, and also the eastern bank of the Mississippi river, through the whole 

 extent of the county, from north to south, but a large portion of these lands 

 were originally prairie, and have been more recently transformed into highly 

 cultivated farms. But little is known of the character of these alluvial beds 

 below the depth of ten or twelve feet, this much only being exposed in the 

 channels of the streams by which they are intersected, but if we could penetrate 

 down to the solid rock bottom, we should most probably find formations which 

 do not appear any where in this region above the surface. That the broad 

 valley of the Mississippi, and other western streams, was formed long anterior 

 to the existence of the rivers which now occupy them, admits of no question, 

 for at many points we find this valley partially filled with beds of drift clay and 

 gravel, exactly like that which covers the adjacent highlands, showing that the 

 formation of the valley antedates the Drift period, but whether these vallies 

 existed during the Tertiary age, or the age preceding the Drift, is a point not 

 yet fully settled, though some facts have been observed which lead to that con- 

 clusion. If we could see a complete exposure of the beds underlying these 

 alluvial bottoms, down to the solid rock on which they rest, it is quite probable 

 that evidence might be obtained that would help to determine this interesting 

 question. 



So far as these alluvial deposits can be determined by the natural exposures 

 in the banks of the streams, they consist of alternations of clay, sand and loam, 

 in quite regular strata, but of variable thickness. On the east side of the 

 county, there is very little bottom land from the south line of the county to 

 the northern part of township 4 south, range 2 west, where it begins to widen, 

 and from that point to the north line of the county, the bottoms along the Illi- 



