Tri-State Mining District and the Mississippi Valley Mineral Belt.

Sphalerite in the Arbuckle dolomite of Western Kansas was described by the writer in 1948 (1). Continued drilling has established two areas of sphalerite and possible jasperiod-type chertification in Upper Arbuckle dolomite, at depths below surface of from 4,900 to 6,440 feet. The deepest sphalerite mineralization, previously known in the Missis-sippi Valley, ranges from the surface to about 1,000 feet in depth in the Southeast Missouri Lead Belt, and to less than one-half that depth in th