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Chert Types of Illinois |
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Burlington Limestone Cherts |
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Burlington Limestone is a Early Mississippian Aged Limestone. In Illinois it is exposed along the Mississippi river from "Quincy, Adams county, to near Alton, Madison county" and also in Monroe county, Illinois(Willman, ect. 1975). Within Burlington Limestone chert has formed. Three types of chert quarried from this limestone are Burlington, Grime Hills, and Crescent Hills. Crescent Hills chert is not a Illinois chert, but it has been used by early Illinois residents. |
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Burlington |
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Grime Hills |
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Cresent Hills |
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St. Louis Limestone Cherts |
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The St. Louis Limestone is a Mississippian aged Limestone. It lies over the Warsaw-Salem Formation (Willman 1975). Two Illinois chert types that outcrop in St. Louis Limestone are St. Louis chert and Cobden/Dongola chert. Sometimes Cobden/Dongola are seperated into two types. On this website they are described as a single type with two variations. |
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St. Louis |
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Cobden/Dongola |
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Devonian Chert |
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Two types of Devonian aged chert are Grassy Knob and Clear Creek Chert. They are lower Devonian in age and occupy most or all of the stratographic layer. Outcrops of these two chert types occure in Jackson, Union, and Alexander counties, Illinois in the Mississippi River Bluffs. |
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Grassy Knob |
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Clear Creek |
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Other Chert Types |
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Mill Creek |
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Moline |
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St. Genevieve |
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Fern Glen |
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Chouteau |
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Kaolin |
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Bibliography |
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Timeline |
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