Watch List notes:

Potosi, Bolivia, cob 8 reales, 1664E.S-P37a; KM-21; Cal-1528.24.95 grams.Oblong flan with partially crude edge (possibly lightly shaved long ago), choice full cross and full pillars-and-waves (well-centered strike), bold date and assayer and two mintmarks, attractively toned VF.
($250-375)