Finberg catalogued this sketch as a reconstruction of the Temple of Vespasian in the Roman Forum, although it is not clear what led him to this assumption. The details of the entablature do not correspond to the surviving fragments and the scrolls within the capitals have more in common with the Temple of Castor and Pollux. Thomas Ashby however, believed that it was a representation of a temple copied from a bas-relief. 1
The sketch is inverted on the page.
Thomas Ashby, unpublished notes, Turner Bequest Archive, Tate.