The U.S. Geological Survey, in cooperation with the Mississippi Department of Natural Resources, Bureau of Geology, is conducting a hydrologic data collection program in potential lignite-producing areas in the outcrops of the Wilcox Group in Mississippi. During August 1985, hydrologic data were collected at a total of 15 stream sites in Benton, Lafayette, Marshall, and Union Counties. Main channel widths ranged from approximately 30 feet to 115 feet. Stream depths during low-flow periods were shallow, generally less than 1.0 foot at most sites. Discharges ranged from 0.04 to 74.8 cubic feet per second. The specific conductance of stream water ranged from 28 to 78 microsiemens and dissolved-solids concentrations ranged from 24 to 59 milligrams per liter. Turbidity values were 20 units or less. Chromium and copper concentrations in bottom material samples ranged from below detection limits (1 microgram per gram) to 5 microgram per gram and mercury concentrations ranged from 0.01 to 0.08 microgram per gram. (USGS)