Report on preliminary data for Madison Limestone test well no.1, NE1/4 SE1/4 section 15, T. 57 N., R. 65 W., Crook County, Wyoming

This report provides the preliminary data for the Madison Limestone test well no. 1 in Crook County, Wyoming, including test-well history, geology of the test well, hydrologic testing, and geochemistry. The test well was drilled to a depth of 4,341 feet to determine the water-resource potential of the Madison Limestone and associated rocks to meet future water needs in a 188,000 sq mi region that includes the coal-rich area of the Northern Great Plains. Drilling and testing were designed to yield a maximum of stratigraphic, structural, geophysical, and hydrologic information. All significant water-bearing units contain relatively freshwater (less than 2,000 mg/liter dissolved solids). Three water-bearing units, which are now cased off, may be potential sources of ground water in the area of the test well. These are the Hulett Sandstone Member of the Sundance Formation, the Minnekahta Limestone, and the upper sandy part of the Minnelusa Formation. (Woodard-USGS)