Cunard Line Contract, "Niagara", Boston - Halifax, Nova Scotia. Cover front (including part of top flap) prepaid to Halifax, Nova Scotia franked with the 1847, 5¢ red brown (four clear to large margins, small faults) cancelled with the Boston grid obliterator. The Cunard sailings were used by the USPO to improve cross border deliveries. Reverse bears the Halifax Exchange Office datestamp, F.-V.F.; with 1998 P.F. certificate. Scott No. 1  Estimate $750 - 1,000. $0 (Image)