Geologic features were derived from source digital data. In addition, geologic features not present with the digital data were  digitized using a .TIF image of the source map that was scanned at 300dpi and georeferenced in NAD83 UTM.  The source map scan was also used to attribute features, as well as to check (QC) line quality, both positionally and spatially, and feature attribution.  Ancillary source map text, including unit descriptions, and graphics, if present, were captured, formatted and added to the map-related pdf file.  See the Process Step section for additional information.