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By: Phillips, Tom Lee, - Avcin, Matthew J., - Berggren, Dwain,Edition:Publication info: Urbana, Illinois State Geological Survey, 1976Volume: Illinois State Geological Survey Education SeriesSeries:Holding Institution: University Library, University of Illinois Urbana ChampaignSubjects: Coal balls Illinois Basin Paleobotany PennsylvanianBHL Collections:
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By: DeMaris, Philip J.Edition:Publication info: Champaign, Ill, Illinois Dept. of Energy and Natural Resources, State Geological Survey Division, 1983Volume: Contract Reports 1983-2Series:Holding Institution: University Library, University of Illinois Urbana ChampaignSubjects: Coal balls IllinoisBHL Collections: