library.isgs.illinois.edulibrary.isgs.illinois.edu/Pubs/pdfs/specialreports/sp-03.pdf · The U.S....
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library.isgs.illinois.edulibrary.isgs.illinois.edu/Pubs/pdfs/specialreports/sp-03.pdf · The U.S. Geological Survey provided 50% of the financial support, geology and mapping expertise,