Copper-alloy ?gilt ?base for the bowl?

Douglas 1793, 52:A Brass or Mixed metal Patera [note omitted], near 6 inches in diameter, and rather more than half an inch in depth. Found inverted as a base to [the copper-alloy bowl]. The bottom, which adhered to that of the large vessel, has some remains of gilding upon it; and which, by being less exposed to the moisture of the earth, is preserved in its natural state. The other parts are covered with a fine variegated deep patina, the same as on [the copper-alloy bowl].Found in 1771; 'Tumulus XV'. According to Douglas 1973, 47 the object was in his possession and is therefore not identical with any of the objects in the Faussett/Rolfe collections. – B.B.