1970. United States. Geological Survey. This data set originated as a Digital Raster Graphic (DRG) produced from a scanned USGS topographic map. The DRG included the collar information an... United States. Geological Survey.
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1970. United States. Geological Survey. This data set originated as a Digital Raster Graphic (DRG) produced from a scanned USGS topographic map. The DRG included the collar information an... United States. Geological Survey.