Unidentified Stamp

Arms:
Quarterly 1 & 4 on a bend three mullets pierced 2 & 3 three horses heads couped (Slade)
Crest: A wyvern
Dimensions (height x width): 26mm x 25mm
Monogram: I D
Initial: I D
Quarterings: 1 & 4 on a bend three mullets pierced 2 & 3 three horses heads couped (Slade)
Heraldic Charges: wyvern
Notes:
Davenport identifies these stamps as those of Marcus Trevor 1st Viscount Dungannon. Both arms and crest belonged to the Welsh hero Tudor Trevor, and are used by his descendants. Because surnames are a recent introduction in Wales, various branches of the family have different surnames. For the lion rampant Papworth's Ordinary lists a good number, of possibilities, among them Davies of London and Shropshire, Davis of Denbighshire and Dymock of Warwickshire, granted in 1581, and Dymock of Penley Hall in Flintshire. For the wyvern crest Papworth gives the following: Drake, Ashe and Withercomb, Devon; Drake, Hardley, Norfolk; Davith. The initials I D would fit any of these families. That of the Viscounts Dungannon do not offer anyone whose name began with I or J.