U.S. #630 White Plains Souvenir Sheet Used

U.S. #630
International Philatelic Exhibition Issue Souvenir Sheet - Used
This is a rare specialty item, seldom seen as the vast majority of the Souvenir Sheets left the International Expo as Souvenirs of attendence at the exent (thus the term Souvenir Sheets). This item actually served the purpose of posting for the mail.