Suggested citation and version history for


  Causey, J. Douglas, 2007, revised 2009, Mining claim 
       activity on federal land in the United States:  U.S. 
       Geological Survey Data Series 290, v. 2.1 
       [http://pubs.usgs.gov/ds/2007/290/].


  Version 2.1, July 28, 2009
  Updated and expanded the .zip data package for Nevada

  Version 2.0, December 18, 2008
  Mining claim statistics and shapefiles are updated (to 
    the end of 2007) with newer data obtained from BLM. All 
    the original data have been replaced with new data in 
    this version. 

  Version 1.1, April 25, 2008
  Updated and expanded the .zip data package for Nevada

  Version 1.0, November 20, 2007
  Initial release online at
  http://pubs.usgs.gov/ds/2007/290/