This page contains several sketches of the so-called Temple of Apollo, a ruined Roman bath-house which stands on the eastern banks of Lake Avernus, a volcanic crater lake near Pozzuoli which is represented in classical mythology as the entrance to the underworld. The most well-known prospect of the lake was that looking south towards the Bay of Baiae and the promontory of Cape Misenum (present-day Capo Miseno). However, in the top left-hand corner Turner depicts the view looking north with the ruined temple in the foreground and Monte Corvara in the distance beyond. A similar composition was depicted by John ‘Warwick’ Smith (1749–1831) in Select Views in Italy, and a copy of this plate can be found in the Italian Guide Book sketchbook (Tate D13969; Turner Bequest CLXXII 20a). The study in the bottom left-hand corner continues on the opposite sheet of the double-page spread, see folio 78 (D15709; Turner Bequest CLXXXIV 76). For further sketches of Lake Avernus and a discussion of Turner’s related paintings see folio 19 verso (Tate D15592).