Watch List notes:

Potosi, Bolivia, cob 8 reales, 1651 O, with crowned-F (Mastalir Fa2) countermark on shield, very rare, Mastalir Plate. S-P35; KM-19b; Cal-1489. 24.66 grams. Broad flan with much legend including full 1651 date (Spanish 5, hence a unique subtype), good shield and cross, the former with bold P-O to left and 8-O to right (the latter rotated from doubling), more than half the countermark clear on shield, nicely toned all over. Pedigreed to the Roberto Mastalir Collection of Countermarked Potosi Cobs, Plate Coin (page 118 in Part A and page 334 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
($350-500)