USBM I.C. 8335 POTEN. SOURCES OF ALUMINUM 1967IND. GEOL. SURV. C. 266 COAL RESOURCES OF INDIANA 1953USGS B. 708 HIGH GRADE CLAYS OF THE EASTERN USIND. GEOL. SUR. REPT. OF PROG. NO. 11 PA. CLAYSPETERS FRANK A. AND PAUL W. JOHNSON BUMINES I.C. 8648 1974PETERS FRANK A. ET.AL. BUMINES R.I. 6927 1967USBM TECHNICAL PAPER 417 ANALYSESOF INDIANA COALS