Watermark: Probably fleur-de-lis inside double with circle. Watermark
Drawing is on fragment of a proof impression of an etching from "Antichita ̉d'Albano e di Castel Gandolfo," 1764, f. 526, pl. XVII.
This sketch for a chimneypiece incorporates decorative elements encountered elsewhere in Piranesi's work: the medallions found even in his early Venetian drawings, the shell seen in his Lateran designs, and the dolphins adopted from archaeological fragments.