Geology and zinc-lead deposits in the Durango area, Dubuque County, Iowa
Arthur E. Flint, C. Erwin Brown
1955, Miscellaneous Field Studies Map 33
Geologic investigations were begun in Iowa to appraise; (1) the possible occurrence of zinc ore in strata that elsewhere in the Upper Mississippi Valley zinc-lead district have been the principal sites of zinc concentration; and (2) lead ore of the type known as "crevice deposits," which were mined so extensively...
Zinc and lead deposits of the Sinsinawa River area, Grant County, Wisconsin
John W. Allingham, Arthur E. Flint, Allen F. Agnew
1955, Miscellaneous Field Studies Map 40
A broad geologic study of the structure and ore deposits of the Wisconsin-Illinois-Iowa zinc-lead district (fig. 1) was begun by the U.S. Geological Survey in 1942. The main object of the present program is to delineate the areas favorable to future exploration for zinc-lead ore deposits. As part of the...