Watch List notes:

Potosi, Bolivia, cob 8 reales, (1651) E, with crowned-F (Mastalir Fb2-x) countermark on cross, very rare, Mastalir plate. S-P36; KM-19b; Cal-1491. 11.69 grams. Bold dot-F-dot of countermark (one of only two known of this sub-variety to appear on the cross side), the cross (well toned) and shield both full but doubled, but all very thin from corrosion. Pedigreed to the Roberto Mastalir Collection of Countermarked Potosi Cobs, Plate Coin (page 356 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 Herman Moro certificate. From: Capitana, sunk in 1654 off Chanduy, Ecuador
($200-300)