These two sketches, drawn with the book turned to the right, continue a series of small sketches of a distant view of a castle on a hill from folio 20 (D26297). The most likely identification for the ruin is Craignethan Castle as seen from across the River Nethan to the south as the sketch follows a sequence of different views of the castle (see folio 14 verso; D26286 for details). The general shape of the building and the topography fit well. It is, however, worth mentioning another possibility, Cadzow Castle, which Turner is likely to have passed on his way to Bothwell after visiting Craignethan and Douglas.1 The ruins also make a good match for that building, as does their position on the edge of a deep gorge with a narrow river running through it.
Noted by David Wallace-Hadrill, [CCLXIX Checklist], [circa 1991], Tate catalogue files, unpaginated MS.