[This is the last in a linked series of articles about Dumbarton Rock. See the end of Link
(the first article in the series) for a list of the reference works that are cited here in abbreviated form.]
Of the two peaks that make up Dumbarton Rock, the western peak, White Tower Crag, is the higher, at 73 metres.
At present, the main structures on White Tower Crag are a trig point (NS3974 : Trig point on Dumbarton Rock
), a flagstaff, and the toposcope (or topograph: these indicate directions and distances to various points of interest) that appears in this photo, partly enclosed by the ruined semicircular base of a building. (The foreshore area at Levengrove is visible in the background, behind the pillar.)
Early in the site's history, when the Rock served as the fortress of the Strathclyde Britons, "the western of the two peaks, the White Tower Crag, would have been too pointed for anything other than a look-out post" [HD, p11, 71].
In the medieval period, several buildings were clustered in the level terrace between the two peaks (the Over Bailey – see Link
). However, the western peak was the location of the White Tower, a watch-tower which gave the crag its modern name [HD, p73]; it was apparently at, or close to, the location of the modern direction indicator shown in this image.
The White Tower is shown in John Slezer's view (c. 1690) of the Rock from the north-west [HD, p74], and is mentioned even earlier, in a 1580 inventory [MacPhail, p132]. However, that tower has been completely destroyed; the ruined semicircular base that is currently visible here is of unknown origin [OSG07, p5].
An earlier version of the official guidebook [OSG92, p13] had suggested that it was the base of an eighteenth-century windmill erected near the medieval White Tower; this theory was presumably based on a passage in Dorothy Wordsworth's "Recollections of a tour made in Scotland, a.d. 1803" (published in 1874): the author there recounts a visit to the castle by herself and her brother William, in company with fellow poet Coleridge. The visitors noticed a circular ruin on the summit; on inquiring about it, they were told by one of the soldiers that it was the ruin of a windmill.
Dorothy and companions thought that this was an unusual location for such a structure, and that if there had been a windmill here, it had perhaps been intended only for the use of the castle's garrison. In any case, the soldier may not have been well informed about the ruin's origin: several decades earlier, Thomas Pennant, in "A Tour in Scotland and Voyage to the Hebrides" (1769), mentions that "on one of the summits are the remains of an old light-house, which some suppose to have been a Roman Pharos"; this is probably the same circular base, and its origins appear to have been unclear even then. As noted above, the latest version of the official guidebook to the Rock and castle simply says that the ruin is of unknown origin.
Robert Stuart, in his "Caledonia Romana" (1845), mentions Pennant's earlier account (he is agreement with Pennant about the nature of the ruin), and he devotes some space to a discussion of the structure. I do not believe that there are any Roman remains on the Rock, but Stuart's account is worth quoting, if only for what they reveal about contemporary beliefs regarding the ruins. He states that "tradition has long pointed to the foundation of a circular building, still to be seen near the principal flag-staff at Dumbarton Castle, as the remains of a Roman lighthouse or watch-tower [a footnote here refers the reader to Gough's Camden, III 352]; but nothing beyond tradition can be referred to as evidence on the subject; there, however, are the firmly cemented stones, which have certainly formed a portion of some such structure, by whomsoever it was erected; and, if not Roman, its builders would seem to have, at all events, possessed not a little of Roman skill in preparing the particular mortar made use of in its construction".
As for the toposcope, it gives distances and heights of about forty locations that are up to 32 miles away. Its inscription reads:
Height 240.4ft : Lat. 55°56´ : Lon. 4°33´ W
M – Miles. H – Height in Feet.
This Plate presented to
H.M. OFFICE OF WORKS.
Sir Iain Colquhoun Bart., D.S.O. President
PROVOST BILSLAND – DUMBARTON.
(Regarding the Association mentioned here, compare NS4076 : Memorial Fountain
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