Orientation was clearly an important consideration when a Clava cairn was being constructed. The orientations of the passages, where they exist, fall without exception within a quarter of the compass between west-southwest and south-southeast. The encompassing stone circles tend to have their stones graded in height with the tallest in the southwest. The southwesterly preference in the orientations of these monuments appears to follow a dominant tradition very similar to the one that controlled the broadly contemporary recumbent stone circles found farther to the south and east.
The most evident concentration of cairns at Balnuaran of Clava comprises two passage tombs and a single ring cairn, all surrounded by stone circles. The two passage tombs are arranged so that their passages are directly in line with each other. The ring cairn, although placed between them, is slightly off to one side and does not obscure the alignment. Alexander Thom visited the site as part of his extensive campaign in the 1950s and 1960s to survey many hundreds of Scottish megalithic monuments. He noted that the two passages were not only directly in line with each other, but also closely aligned upon midwinter sunset. Twenty years later the archaeologist Aubrey Burl completed a study of the Clava cairn orientations and concluded that, while the solstitial alignment was not generally repeated at other sites, the whole group had a consistent, broader pattern of orientation related to the moon. The simplest interpretation is that it related to the midsummer full moon. In this respect, again, the Clava cairns seemed to have much in common with the nearby recumbent stone circles. As it happens, the direction of midwinter sunset falls within the broader lunar range, and the obvious conclusion from considering the monuments systematically as a group was that their significance was in fact lunar, with the specifically solar alignment at Balnuaran of Clava itself being a fortuitous occurrence within this range. The Clava cairns stood for almost twenty years as a clear example of how studying a group of monuments as a whole can modify, and constrain, “oneoff” interpretations of individual sites.
All this changed in the late 1990s when another British archaeologist, Richard Bradley, commenced excavations at Balnuaran of Clava. One of his principal conclusions was that structural risks had been taken in order to conform to prevailing norms that (to our view) have no practical value—indeed, that seem to run counter to common sense. These included grading the heights not only of the surrounding stone circle but of the kerbstones and other stones within the cairn that governed its structural integrity: the tallest were placed on the southwestern side, something that made the overlying cairn structure inherently rather unstable. This confirms the importance of orientation but also hints at a much richer set of prevailing symbolic or aesthetic principles that governed the construction of these monuments.
Another extraordinary fact revealed by the excavations was that the various stones used in the construction of the cairns were often not, structurally speaking, best suited for the job. The choice of stone often seems to have had more to do with color than with (what we would see as) practical necessities such as size, shape, or strength. Most intriguing of all, stones of certain colors predominated in different parts of the cairns—with, broadly speaking, a preference for white stones facing sunrise in the east but red stones facing sunset in the west. Changes in color seem to have been related to the directions of solstitial sunrise and sunset. It is here that Bradley’s discoveries provide a direct challenge to the lunar conclusion: they suggest that the predominant symbolism at the site was solar. This, combined with the very fact that the solar alignment is so precise—the setting midwinter sun shone down the full length of the passage—argue strongly that the solar symbolism, and particularly the solstitial alignment, were deliberate.
The wider issue that this conclusion raises is methodological. Every aligned structure must point somewhere, and we must seek corroborating evidence if we wish to increase our degree of belief that any particular alignment upon a specific astronomical target was actually intentional or, at the least, came to mean something to certain people in the past. There are two main ways to do this. The first is to investigate whether the alignment is repeated at similar monuments in the locality. The second is to seek a broader range of contextual evidence relating to the case in question: evidence that could inform us about the broader symbolic principles prevailing in that particular instance. The example of Balnuaran of Clava shows the potential of both methods, but also shows that they can be in direct conflict, and raises the question of how we can best achieve a reconciliation in such circumstances. One solution may be to postulate that this site, evidently the most complex and sophisticated in the Clava cairn tradition, incorporated a layer of symbolism relating to the sun that was additional to the more commonplace, and more basic, relationship to the moon.
References and further reading Bradley, Richard. The Good Stones: A New Investigation of the Clava Cairns. Edinburgh: Society of Antiquaries of Scotland (Monograph Series 17), 2000. Burl, Aubrey. The Stone Circles of Britain, Ireland and Brittany, 233–242. New Haven: Yale University Press, 2000. Larsson, Lars, and Berta Stjernquist, eds. The World-View of Prehistoric Man, 123–135. Stockholm: Swedish Academy of Sciences, 1998. Mithen, Steven, ed. Creativity in Human Evolution and Prehistory, 227–240. London: Routledge, 1998. Ruggles, Clive. Astronomy in Prehistoric Britain and Ireland, 130–131. New Haven: Yale University Press, 1999. Ruggles, Clive, and Alasdair Whittle, eds. Astronomy and Society in Britain during the Period 4000–1500 BC, 257–65. Oxford: British Archaeological Reports (British Series 88), 1981. Trevarthen, David. “Illuminating the Monuments: Observation and Speculation on the Structure and Function of the Cairns at Balnuaran of Clava.” Cambridge Archaeological Journal 10 (2000), 295–315.