The Geology of Hardin County, and the Adjoining Part of Pope County, Issue 41

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Illinois State Journal Company, state printers, 1920 - Geology - 416 pages
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Page 275 - ... cooling and consolidation of the underlying mass of rock. The association of the minerals and the common phenomena of marked silicification of the hanging wall are interpreted as indicating deposition from heated ascending solutions carrying fluosilicates of zinc, lead, copper, iron, barium, and calcium. These are believed to have been broken up and precipitated by descending cold waters, which possibly also furnished the sulphur to combine with the metals, though it is not improbable that sulphur...
Page 285 - States is consumed as a flux in the production of steel by the basic open-hearth process. For this purpose, the fluorspar should contain less than 10% of impurities, except that calcite which is frequently present is not objectionable and may run higher. Silica should preferably be less than 2 per cent, though the spar may contain up to 4 per cent. 1 This flux is used principally for giving fluidity to slags that are too viscous, but at the same time it facilitates the passage of impurities such...
Page 208 - Archaeocidaris are more commonly met with in this portion of the Menard than at any other Chester horizon in the region. The bryozoans are represented by the same genera and mostly by the same species that are present in other Chester faunas. Among the brachiopods most of the species are. commonly present...
Page 124 - ... these beds is also placed in this series ; for, so far as my observations extend, it has much stronger affinities with the sandstones in the Lower Carboniferous series than with those in the coal-measures. The following is the best section I have been able to obtain of these rocks. No. 1. 65 feet of a heavy bedded, irregularly stratified, brownish sandstone. It is made up of round and angular pellucid particles, having the interstices filled with a fine, opaque, brown substance, which is often...
Page 275 - ... such waters have been shown to be effective, both the ores and the gangue differ in the' important particulars already enumerated. If it be held that the waters which formed the ores were heated waters, but that they derived their load from the St. Louis, Ste. Genevieve, and surrounding limestones, it may be pointed out that the normal tendency of heated waters rising along faulting fissures would undoubtedly be toward deposition and dissemination of material rather than toward its segregation.
Page 212 - In both regions the sandstone formation occupies the same position in the section, and it maintains approximately the same thickness throughout. There can be no question as to the continuity of the bed throughout the entire Illinois basin of Chester time. CLORE...
Page 201 - ... the exposures in Pope County, however, where the thickness can be estimated with some degree of accuracy, it seems to vary from 100 to 150 feet. About the same thickness may be assumed for this area. The Tar Springs is the thickest of the several Chester sandstone formations in the area. Fossils. — The only fossils that have been observed in the Tar Springs formation in the area covered by this report and in adjoining parts of Hardin County, are plant remains. These have been identified by...
Page 95 - ... Alabama and eastern Tennessee. A possible explanation of the fact may be that the crinoids. bryozoa, and brachiopods. so abundant in the Osage and its equivalent elsewhere, were especially adapted to life in shallow, warm water, such as doubtless existed generally throughout the Osage sea. This region may have been a deeper depression of the sea floor, where the water was too deep for the animals to live upon the bottom, and into which their hard parts were not washed by currents from shallow...
Page 226 - Succeeding the second mass of shale and sandstone is the third conglomerate and sandstone member of the Caseyville, over 100 feet thick, forming the top of the formation. This uppermost member is similar in lithologic character to the two lower sandstone and conglomerate members; it forms the high cliffs near Sellers Landing, and also those at the mouth of Cane Creek and along Blind Hollow, below the mouth of Saline River.
Page 89 - Examples of a species identical with the form in the Chattanooga shale in Hardin County have been collected by Weller in the Sweetland Creek shale of Iowa, and in a greenish shale overlying the black shale in southwestern Missouri.

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