Although Turner drew a more detailed sketch with more of the loch on folio 39, he actually utilised more of the present sketch for his watercolour of
Loch Coriskin 1831 (The National Gallery of Scotland),
1 which was prepared to be engraved to illustrate Sir Walter Scott’s
The Lord of the Isles, as part of a new collected edition of his
Poetical Works. As Gerald Finley has pointed out, Turner relied more on his memory of the place than on his sketches,
2 but the bottom left of the present sketch was followed fairly closely for the left side of his watercolour composition which shows Loch na Cuilce and Meall na Cuilce (the rock to its north) which are both shown in this sketch. The mountains behind were re-imagined into a more triangular ridge that look as if they had been recently rent from the earth by the power of colliding tectonic plates, an effect that was probably inspired (as John Gage has pointed out) by a passage in the geologist John MacCulloch’s
Highlands and Western Isles of Scotland, which Scott may have pointed out to the artist.
3 As Gage put it, MacCulloch and Turner share the characteristics of ‘sublime scale and a precision of geological description’.
4 The shape of this ridge of rock may also have derived from the memory of different views of the Cuillins from around Loch Coruisk. Although the shape is wrong or exaggerated as seen from Sgurr na Stri, it is quite close to Sgurr Alisdair as seen from the level of the loch.