Watch List notes:

Potosi, Bolivia, cob 8 reales, (1650) O, with crowned-a (Mastalir A1c) countermark on cross, rare, Mastalir Plate. S-P35; KM-19b; Cal-1488. 21.80 grams. Good full cross with most of countermark in center, corrosion at edge, full but doubled and lightly corroded shield, toned all over. Pedigreed to the Roberto Mastalir Collection of Countermarked Potosi Cobs, Plate Coin (page 49 in Part B) in his book The Great Transition at the Potosi Mint, 1649-1653, The 1649-1652 Crowned Shield Coinage and the Countermarks of 1652 (2021), with original certificate from the salvors (Maritime Explorations, Inc.). From: Capitana, sunk in 1654 off Chanduy, Ecuador
($300-450)