This faint sketch is unusual among Piranesi's drawings of this type in that it was not worked up in pen, ink, and wash. The architecture studied here is similar to that in the "Parte di Ampio Magnifico Porto," which appeared in the "Opere Varie" of ca. 1750. This is consistent, too, with the paper, which is a type that Piranesi used in the late 1740s.
Watermark: Fleur-de-lis inside circle, surmounted by letters "ACC", with letter "F" below circle, centered on chain line. Same as watermark on 1966.11:7