Danish West Indies, Spanish West Indies Mailboat "D26", sharp bold oily strike of oval barred obliterator tying G.B. 1865, 4d vermilion on folded letter sheet to Fort Lee, N.J., manuscript "Due 10¢" and stamp additionally tied by "N.Y. Steamship, 10, Dec 10" cds, reverse with "Spanish Mail Packet, A, No 8, 68" and "St. Thomas, No 17, 68" backstamps; cover with expert reinforcement or restoration in corners and folds, otherwise Very Fine, One of Only Two Covers and the Unique Usage Canceling a British Stamp on Cover, pictured in Stone's A Caribbean Nepture (pg 111); Spectacular Strike of the Spanish West Indies Mailboat "D26" Obliterator,The Unique Usage of the "D26" Obliterator. SG No. Z191. Estimate  $20,000 - 30,000. This cover was post at Santo Domingo, at the docks aboard the Herrera Line Spanish ship S.S. Moctezuma, which departed on the 9th and arrived in St. Thomas on the 17th of November. There it was sent by British Packet to New York via Havana. This cover is one of two known, the other bearing a Spanish franking and is addressed to Havana. The "D26" barred oval is among the rarest of all British Used Aboard cancellations, as approximately 20 British stamps are known bearing this cancellation. $0 (Image)