used alongside 6c Dull pink Banknote (159), tied by two NYFM geometrics (Weiss GE-EP3) to 1875 cover to Pont-de-Vaux, France at double the 9c treaty rate plus 18c supplementary mail fee, red "New York Paid Dec 4" exchange datestamp, blue crayon "2" for double weight, Calais entry and framed "PD" handstamp, forwarded to Paris with various backstamps, very fine, a rare 30c Banknote use on supplementary mail