Keywords: Parcel Post PlBlk 10c 1912 issue.JPG en Image of a Parcel Post 'plate block' ox six 10c 1912 issue 1912 U S Post Office; Smithsonian National Postal Museum Bureau of Engraving and Printing; Imaging by Gwillhickers PD-USGov Uploaded with UploadWizard Stamps of the United States 1911-1920 |