The geology of Hardin County, and the adjoining part of Pope County . ° and 65° were observed. The mineral bodies of the main veins, as exposed in the workings, arethin lenses joined to one another, both vertically and horizontally, by vein 1 These ridges, due to silicification of sandstone along faults, are called quartzitereefs, by Bain. Bain, H. Fester, The fluorspar deposits of southern Illinois : TJ. S. Bull. 255, p. 33, 1905. ECONOMIC GEOLOGY 251 material, so as to form thin tabular masses with a series of pinches andswells. Whether viewed along the course of a drift, or from
The geology of Hardin County, and the adjoining part of Pope County . ° and 65° were observed. The mineral bodies of the main veins, as exposed in the workings, arethin lenses joined to one another, both vertically and horizontally, by vein 1 These ridges, due to silicification of sandstone along faults, are called quartzitereefs, by Bain. Bain, H. Fester, The fluorspar deposits of southern Illinois : TJ. S. Bull. 255, p. 33, 1905. ECONOMIC GEOLOGY 251 material, so as to form thin tabular masses with a series of pinches andswells. Whether viewed along the course of a drift, or from successive levelsalong a vertical line, the developed veins show variations in width from almostnothing up to forty feet. Thus in the Fairview Companys workings in theAnnex-Extension mine, the 200-foot level extends from near the river north-ward for about 1,700 feet. At the south face the vein width is 7 feet; fromhere to the Annex shaft, a distance of 900 feet, it fluctuates considerably,nearly pinching out at the shaft for a distance of 25 feet; it then widens.
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectgeology, bookyear1920
