Obverse: An armored, laureated bust of Carlos IV, facing right.
CAROLUS IIII DEI GRATIA 1808
Reverse, a crowned coat of arms of Spain consisting of a quartered shield with castles and lions in the quarters. In the small center shield are three fluers de lis. At the bottom of the shield is a pomegranate. Beside the shield are two columns.
PLUS VUTRA, is inscribed on the ribbons which are wrapped around the columns.
HISPAN ET IND REX (small 'o' over capital 'M'--for Mexico City mint); 8R (8-reales) TH (assayers initials).
Original coin weighed 26.83 grams, was 40 mm in diameter and was .896 silver.
And what appear to be: 3 Chinese 'chop marks' on the king's breastplate--as Iron Patch mentioned above.
Don..