Watch List notes:

Potosi, Bolivia, cob 8 reales, (1650) O, with uncommon crown-alone (Mastalir K8) countermark on cross, rare, Mastalir Plate Coin. S-P35; KM-19b; Cal-1488. 20.70 grams. Choice full countermark (identical to one seen on a contemporary silver bar found in Panama), the rest of the coin somewhat flat and worn but not too badly corroded, toned in crevices. Pedigreed to the Roberto Mastalir Collection of Countermarked Potosi Cobs, Plate Coin (page 311 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 photo-certificate. From: Capitana, sunk in 1654 off Chanduy, Ecuador
($300-450)