U.S. GEOLOGICAL SURVEY DIGITAL DATA SERIES DDS-18-A

                     National Geochemical Data Base: 
                National Uranium Resource Evaluation Data
                   for the Conterminous United States


                                 OVERVIEW

       This CD-ROM (Compact Disc-Read Only Memory) contains the geochemical 
       data for the conterminous United States collected during the National 
       Uranium Resource Evaluation (NURE) Hydrogeochemical and Stream 
       Sediment Reconnaissance (HSSR) program.  The data are from the 
       National Geochemical Data Base.  The CD-ROM contains the results of 
       work performed by the Bendix Field Engineering Corporation, Operating 
       Contractor for the U.S. Department of Energy (DOE), as part of the 
       NURE program, and  by the U.S. Geological Survey.  This CD-ROM 
       supersedes DDS-1, "National Geochemical Data Base: National Uranium 
       Resource Evaluation Data for the Conterminous Western United States," 
       released in 1991.  

       The area of coverage for data on this CD-ROM is shown on the back of
       the insert in the CD-ROM jewel box.  Samples were collected from
       320 quadrangles (1 degree X 2 degrees) beginning in 1976 and ending 
       in 1980.  Data are included for 678,558 records representing four
       predominant sample types: stream sediment, soil, surface water,
       and ground water.  Each sample was analyzed for uranium and for as
       many as 58 other elements plus sulfate.  
       
       The data are as received from the DOE after completion of the NURE
       program, but have been compressed and indexed for use with the
       GSSEARCH software.  The structure of the NURE data on the CD-ROM 
       requires the GSSEARCH software be used for access.

       Data searches and retrievals are made by using GSSEARCH, supplied on 
       the CD-ROM.  The data may be searched by sample type, quadrangle, 
       latitude, longitude, element, element concentration range, or any
       combination of these criteria.  Once a satisfactory search has
       been made, the data may be retrieved in several different formats to
       the user's hard disk.  Within GSSEARCH, context-sensitive help
       files are available.  The locations of samples may also be plotted
       on a map of the conterminous United States using MAPPER software, 
       also supplied on the CD-ROM.