Watch List notes:

Potosi, Bolivia, cob 8 reales, 1651O, with crowned-A countermark (very rare) on cross. S-P35; KM-19b; CT-510. 20.64 grams. Corroded all over (and with distracting dark patches on cross) but with technically full shield and cross and distinctive countermark, also most of date with doubling on last two digits followed by ornament (looks like 1650 but it's not). From the Maravillas Research Collection of Countermarked Potosi Cobs, with Marex certificate and tag #0936. Recovered from: Maravillas, sunk in 1656 off Grand Bahama Island ($350-500)