Enhanced Historical Land-Use and Land-Cover Data Sets of the U.S. Geological Survey: Data Source Index Polygons
This polygon data set provides ancillary information to supplement a 
release of enhanced U.S. Geological Survey (USGS) historical land-use  
and land-cover data.  The data set presents some of the original file-header 
documentation, as well as some details describing how the data files were 
used in the data …