Cloth Seal, Cloth Worker's Personal Seal, Pictorial, Mermaid, HP, Image by Peter Evans.
Found it in Flintshire, 18mm.
FC incuse (possibly O at top) 4 scratched 1's // mermaid holding object in left hand, H P to sides
Probably a cloth worker's personal seal where the cloth worker is denoted by this pictorial device ande initials HP.
See
BSG.CS.00870 for similar seal.