MEXICO. "Early Series" Cob 4 Reales, ND (1536)-M R. Mexico City Mint. Carlos & Johanna. NGC AU Details--Environmental Damage.
KM-0016; Cal-type-43#115. Rounded Panel Variety. A reasonably well detailed and RARE issue, with mintmark, denomination, and assayer letter clear. The latter has been confused by a strong double strike that superimposes one "R" on the other. The coin has been affected by corrosion, though now the surfaces are toned a pleasing dark gray.
Estimate: $1250 - $1750