RARE DUBLIN 'SIGNET' DATESTAMP EARLIEST KNOWN DATE OF USE - 16 Mar. 1857 EL to Dublin with 1856 1d red tied by fine BELFAST spoon and with very fine and rare DUBLIN datestamp in the shape of a signet ring positioned nicely on the lower flap; this is believed to be the earliest known date of this mark.Cross Reference: 1854-65 1d REDS, SPOONS & SIDEWAYS DUPLEXES, ETC., BELFAST (Image)