| Reference | {Deposit:: F1 < HEYL, A. V., AGNEW, A. F., LYONS, E. J., AND BEHRE, C. H., JR., 1959, THE GEOLOGY OF THE UPPER MISSISSIPPI VALLEY ZINC-LEAD DISTRICT: U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 309, 310 P.}{Deposit:: F2 < OWEN, D. D., 1844, REPORT OF A GEOLOGICAL EXPEDITION OF A PART OF IOWA, WISCONSIN, AND ILLINOIS IN 1839: U.S. 28TH CONGRESS, FIRST SESSION, SENATE EXECUTIVE DOCUMENT V. 7, NO. 407, 191 P., MAPS.} |