horizontal pair, margins large to barely touching at lower right (portion of adjacent stamp at left), tied to 1849 folded letter sheet to Philadelphia by three strikes of blue "10" in oval, matching "Baltimore May 11" datestamp at left, delivered to New York by mistake where red "Missent" and "Forwarded" straightline handstamps were applied along with a "New-York May 12" datestamp, right stamp tiny corner crease, extremely fine, a beautiful and desirable example of auxiliary markings on an 1847 issue cover, ex-Newell, 1985 and 2006 Philatelic Foundation certificates