The stable carbonate platform of the U.S. midcontinent is host to the largest concentration of Mississippi Valley-type (MVT) zinc-lead mining districts in the world. Of these districts, the Southeast Missouri Lead District which includes the main Viburnum Trend and Old Lead Belt subdistricts, is unique in several ways. Lead dominates over zinc and the ores have significant amounts of copper, silver, cobalt, and nickel. Hosted in the Upper cambrian Bonneterre Formation, above the basal Cambrian Lamotte Sandstone which is underlain by felsic Precambrian basement, the Viburnum Trend is situated very low in the carbonate section when compared to the other districts of the region. Of the Ozark districts, the Southeast Missouri Lead District is also unique in its proximity to the Reelfoot Rift which is concealed beneath the Mississippi Embayment. The possible importance of the Reelfoot Rift as a pathway for brine migration from a southerly source has recently been demonstrated by Farrand Land (1985) and Farr (1987). Detailed descriptions of the mines of the Viburnum Trend are given in a special issue of ECONOMIC GEOLOGY (V. 72, NO. 3, 1977). Other informative background papers on the ore deposits of the Southeast Missouri Lead District include those by snyder and Gerdemann (1968), Gerdemann and Meyers (1972), Davis (1977) and Sverjensky (1981).