Response to Douglas Scott’s July 2011 paper “Astronomical observations at Kintraw in Argyll”, in Past Horizons
Scott maintains that Alexander Thom’s interpretation of the Kintraw standing stone, Argyll, as marking an accurate midwinter sunset is a myth, but the evidence he cites is not strictly relevant. A higher observation point than that at the standing stone – such as the nearby prehistoric burial cairns – is needed to see the midwinter notch on Jura over a nearby ridge. However features of the cairns at the site are not relevant because they do not affect the existence or otherwise of the long alignment. Other evidence which is relevant is not discussed, and is reviewed here. An alternative higher observation point was found by Thom on the steep hill slope NE of the stone and excavations here in 1970/71 found a level rubble pavement behind two massive low boulders forming a notch to stand in. The declination of the mountain notch on Jura as seen from this platform is exactly right for midwinter sunset at about 1800 BC.
Petrofabric analysis conﬁrmed that the rubble pavement is almost certainly man-made. Another boulder in an almost identical position 48m upstream failed to produce a pavement behind it, which it should have done if the stone layer was of natural origin. Final conﬁrmation that the hill platform is the primary viewing point is provided by a small standing stone about 1m high even further up the steep hill slope behind the platform. Kintraw is thus an extremely important site because the excavations on the hill slope were in effect an independent archaeological test of Thom’s long alignment hypothesis – so far the only one ever carried out. The test vindicates Thom’s ideas decisively.
Douglas Scott’s 2011 paper “Astronomical observations at Kintraw in Argyll” concludes that Alexander Thom’s hypothesis about the site is a myth. This states that the standing stone there marked the observing position for a long and accurate sight-line to a conspicuous notch between two peaks on Jura, which was capable of deﬁning sunset on midwinter’s day exactly. This conclusion is based an an examination of archaeological evidence, concerning the burial cairn next to the standing stone, which is not essential for that hypothesis. There is in fact plenty of other information from the site which decisively supports Thom’s ideas but it is not considered. This is not unusual; the Royal Commission’s account of 1980 fails to mention it either, although it does refer the reader to the relevant publications (RCAHMS 1988, pp. 64-67 and note 4).
Thom’s interpretation of Kintraw (grid ref. NM 830 050)
Thom’s original 1954 publication about the potential of the Kintraw standing stone as a 28 mile long, highly accurate midwinter sunset alignment is unlikely to have come to the attention of archaeologists. Right at the beginning he recognised that there was a difﬁculty with the interpretation; one cannot see the distant foresight (a V-shaped notch between two of the Paps of Jura) from beside the standing stone because of an intervening ridge about a mile away (Fig. 1). A higher observation point was needed. The ﬁrst mention of the site in a book (Thom 1971, p. 39) explains his reasoning. “To see the col” (on Jura) “ one must move to the right, where the azimuth of the col is too low to give the solstice, or climb some structure such as the cairn, which is in the correct position. How did the builders know where to place the cairn when they could not see the col from ground level?” One might add, how did they know where to put the standing stone itself? “The answer, obvious now, is that they ﬁrst established a position on the steep hillside to the north of the plateau.”
It is important to note that it was Thom himself who suggested that the massive burial cairn next to the standing stone was intended as the primary observing position. The hypothetical location on the steep slope northeast of the cairn and beyond the stream gorge was seen as simply a temporary device to make sure the cairn was built in the right place. Hence Douglas Scott, and others before him, were quite right to challenge this view and to try to show that there was no evidence from the cairn itself to support this idea. Even more important is the inherent assumption that the cairn was contemporary with the standing stone and if Thom’s interpretation of its primary purpose was an essential part of his long alignment hypothesis then this would be a major ﬂaw in his argument as this is quite unprovable; it could easily be later or earlier than the stone and therefore have nothing to do with the alignment.
The Kintraw cairns
However Scott has offered some quite plausible hypotheses which imply that the cairn builders arranged orientations – from the central post under the larger cairn – towards mid-summer sunset and sunrise, and also towards midwinter sunset and to the Quarter Day sunsets at the beginning of February and November. Essential evidence to support these ideas is however missing. If these supposedly calendrically signiﬁcant lines were more than mere ceremonial orientations – like the east-west arrangement of Christian churches – each should point to some conspicuous notch or hill slope on the horizon to give a minimum of accuracy. However drawings of the horizon points concerned are not given. In any case any useful sight-lines must obviously pre-date the cairn, through which they pass. However the ‘sight-lines’ may not even be that, but ritual lines built into the architecture of the cairns for purely ceremonial purposes.
Scott’s argument essentially seems to be that these cairn orientations are all there are to be discovered on the site. He writes “It seems unlikely that, if the winter solstice sun setting in the notch was important to the cairn builders, they would have placed the cairn in a position where all of the notch could not be seen. Indeed, from the centre of the cairn, as the notch is not indicated by any part of this monument this also means that there would be no need for any observers on the hillside terrace. It seems that by ignoring the actual orientation of the cairns and projecting his Jura notch concept onto the site, Prof. Thom created a myth which many people still believe.”
This implies that the only plausible way of looking at the midsummer sunset notch from the ﬁeld with the standing stone is to stand on the large cairn. By making this supposition the evidence of the hill platform can be the more easily dismissed without examination. “During Euan MacKie’s excavation of the terrace, no signs of human activity were found “ (my emphasis) “but it was suggested that two boulders and some ﬂat stones were the remains of a paved observation area.” This is not quite fair, so I shall explain again here what actually was found there, even though it was published in detail in 1974.
The Kintraw hill platform
Thom discovered a ‘large stone’, at the right height (14 ft) above the ﬁeld, on the steep slope beyond the stream gorge and assumed it to be the spot from which the large cairn was positioned; this in turn assumed that the cairn was built to serve as the actual observing point to see over Dun Arnal, the nearby ridge which obscures the notch on Jura from the ground beside the standing stone. However a stone cairn of uneven, heavy rubble is not a comfortable spot on which to stand to make exact observations and moreover – as Scott observed – the line of sight to Jura does not pass over its centre, as one would expect, but near its north-west edge (Fig. 3). However if the boulder on the hill slope was the primary observing position the cairns would then become irrelevant. One thing that would be needed for such an observing point would be a reasonably ﬁrm and level stone ﬂoor next to it on which the observers could stand without worrying if they were going to overbalance and fall into the gorge while staring into the distance at Jura. There was no sign of such a ﬂoor so my excavations of 1970 and 1971 were designed to ﬁnd it or disprove its existence.
One of the ﬁrst discoveries was that the boulder was in fact two massive stones, which appeared to have been arranged to form a small notch in which was a level layer of rubble (Fig. 5). Fig. 5 shows the ‘boulder platform’ at an early stage of the excavations in 1970 and Fig. 6 is my plan and cross sections of the site as exposed in 1971; it shows almost the maximum extent of the excavations, although there was another long trench running up hill just beyond the left edge of the plan. The plan shows how the pavement is strictly limited in area – being quite wide immediately behind the boulders but extending to the right (south-east) as a narrower path. Similarly the cross section a-b and the longitudinal section c-d show how the stone pavement was much more level than the surface of the earth which had subsequently accumulated on top of it. The south-east limit of the pavement was not reached; this was the direction in which any preliminary observations of sunsets immediately before and after the solstice would have to have been taken. However there is general agreement that one would be lucky to get more than one such because the notch disappears behind the higher part of Dun Arnal very soon after moving to the left of the boulders. This point is considered again later.
Although the fact that no charcoal, pottery or ﬂint implements were found associated with the stone pavement means that there is at present no independent means of dating it, the petrofabric analyses described in the next section leave almost no room for doubt that it was a man-made structure. It seems quite likely that the two boulders were dragged to their present position, and underpinned, before the stone ﬂoor was laid.
In 1971 the BBC made an excellent programme called ‘Cracking the Stone Age code” for its Chronicle series which examined Thom’s ideas, and my excavations at Kintraw featured in it. This programme can be viewed at http://www.bbc.co.uk/ archive/chronicle/8604.shtml.
The second boulder
At a distance of 46m upstream from the ‘observation boulders’ is another fairly massive stone, resting similarly on the edge of what is assumed to be the same natural ledge at the lip of the steep stream gorge. There is a similar ﬂattish area between it and the steeper uphill slope and if the excavated stone layer at the ‘observation boulders’ is of natural origin then there should be a similar layer at this more south-easterly stone. However there was no trace at all of any such thing; deep red earth containing scattered stones was found to a depth of at least 1.5m (Fig.7).
Because of the absence of any dating material on the platform, or any artefacts, a different kind of analysis was required to test whether the layer of stones behind the boulder was a natural accumulation or laid by man. Such layers of stones do accumulate naturally if soil gradually moves down a slope, for example as scree. The petrofabric analysis was kindly undertaken by Mr J S Bibby of the Macaulay Institute of Soil Research in Aberdeen (Bibby 1974).
When soil soliﬂucts (moves naturally) downhill the long axes of any stones in it tend to align themselves among the direction of the slope and this can be measured as a compass bearing; the angle of dip of the long axes depends on the angle of the slope and can be measured with a clinometer. The analytical technique is to measure the orientation and dip of one hundred stones in a deposit and plot the results on a Lambert polar equal area net (Fig. 8 a). The results from the Kintraw analyses were explained by Bibby (1974, 193); the original work should be consulted for more details (the Fig. 8 referred to below is Fig. 8 in this internet paper). The results are so important that the main conclusions are quoted in full.
“Two contoured petrofabric diagrams from Kintraw are reproduced in ﬁg. 8b and c. The salient features are the wide variation in the dip of the a axis,” (i.e. compass direction) “and the relatively low angles of inclination. There is a concentration associated with the slope of the ground surface but it is not a strong one. By contrast, ﬁg. 8e is derived from an area of scree and ﬁg. 8f is from a stone pavement produced by frost action and since modiﬁed by soliﬂuction processes. In the diagram derived from scree there is a marked association both with direction of slope and with its inclination; this trend is even more apparent in the diagram representing the structure within the soliﬂucted stone pavement. It appears that the process of soliﬂuction, involving mass creep lubricated by melt water, imposes a strong degree of orientation on the constituent particles. The strong degrees of orientation shown by ﬁg. 8e and f are in obvious contrast to the weak orientations shown in ﬁg. 8b and c.
No information was available concerning patterns produced on fabric diagrams by data drawn from man-made stone pavements. In order to obtain some check, however tentative a visit was made to the Sheep Hill vitrified fort, Milton, Dunbartonshire where a pavement exists that has been identified as man-made by
independent evidence.” (MacKie 1976) “The resulting diagram is shown as ﬁg. 8d which, allowing for the different direction of ground slope, is closely similar to ﬁg. 8b and c. This resemblance is all the more remarkable because of the contrast in parent materials and stone shape between Kintraw and Sheep Hill, the former being dominantly tabular schists and the latter wedge-shaped basalt.
The evidence from petrofabric analysis indicates that the stone horizon discovered at Kintraw bears little resemblance in structure to superﬁcially similar horizons known to have been formed by the actions of frost-heave or by scree accumulation. Other forms of genesis are rendered unlikely by the peculiar combination of lithological and site conditions obtaining. The available evidence supports the hypothesis that the Kintraw pavement was man-made.”
Presumably Scott had not quite digested the full implications of that report when he wrote “During Euan MacKie’s excavation of the terrace, no signs of human activity were found but it was suggested that two boulders and some flat stones were the remains of a paved observation area” (Scott 2011).
The ‘watch stone’
On Thom’s original plan of the site (Fig. 1) the main standing stone is marked as ’S’ and ‘S4’ and is what turned out to be the double boulder-and-notch with the laid pavement behind it. These two, as noted earlier, form a line which points directly at the sunset notch on Jura. At a height of 53 feet above the former is ‘S5’ – a small standing stone about 1m high, still upright although set into a very steep slope (Fig.9); it is slightly to the north-west of the line to Jura. Thom suggested that this stone marked a position from which an observer could give a warning of the imminent midwinter sunset to people on the hill platform below. As can be seen from my drawing of the view from the hill platform (Fig. 10) the upper limb of the Sun would be seen only momentarily at the base of the notch after disappearing behind Beinn Shiantaidh, and an observer higher up would have been able to say when it was approaching the notch.
This little standing stone is of crucial importance and to my knowledge has never been discussed adequately in a published work after Thom’s brief description in 1971; I didn’t realise its full signiﬁcance until about 2008. It certainly should have been mentioned in the Royal Commission’s account (RCAHMS 1988). The presence of this clearly man-made feature above the hill platform is highly convincing conﬁrmation of the importance of that platform as a solstice observing point, and surely indicates that it was the primary such point and not just a temporary marker to help position the large cairn. The solidity of the double boulder, the way the two stones form a small notch, and the presence of the laid rubble pavement behind them all conﬁrm this.
All this evidence surely conﬁrms decisively that the primary astronomical sightline at Kintraw is to the midwinter sunset as Thom claimed. Moreover this is a true long alignment, or practical observing instrument, and not a short ceremonial orientation, and one moreover which was very probably capable – under the right atmospheric conditions – of pinpointing the solstice to the exact day. The back sight was the painstakingly constructed hill platform of which the two boulders were probably manoeuvred into position to form a neat notch (marking the exact observing position) and also serving as a massive revetment for the level rubble pavement which was laid behind and on either side of them. The tall standing stone was simply a ceremonial marker – indicating that this was an important observing site – although it also serves as a pointer towards Jura from the hill platform. This however is hardly necessary as the notch formed by the two Paps of Jura is one of the most striking features on the horizon (Fig. 3).
One ﬁnal issue must be dealt with. It has been claimed that the hill platform cannot be a genuine solstice observing point because there is no way its position could have been established from the natural terrace on the steep hill slope (Patrick 1981, p. 211); moving only a short distance to the south-east of it causes the Jura notch to disappear behind Dun Arnal, so the necessary preliminary observations of the sunset for several days before the solstice would have been difﬁcult if not impossible. However this pre-supposes that the discoverers and builders of such sites had no pre-existing knowledge of the dates of the solstices, and needed the long alignments to establish them in each place they went to. It is clear now however that the detailed solar calendar inferred by Thom from standing stone alignments was already in existence before 3000 BC; it is marked in great detail on one of the carved kerb stones of the great burial mound at Knowth in Ireland (MacKie 2013). The accurate solstitial and other calendar alignments were presumably for keeping track of the solar calendar over many years.
The really important thing about Kintraw however is that it provided the ﬁrst scientiﬁc test of Alexander Thom’s long alignment hypothesis, a test which the idea has passed with ﬂying colours. Thom effectively predicted that there would be an observing platform on the steep slope north-east of the standing stone and this was duly found by excavation. He did not realise of course that it would be so massive and permanent as to render redundant his idea that the main observing position was on top of the large cairn. This however makes the site even more plausible as an accurate midwinter observatory because – apart from its being an uncomfortable spot on which to stand – the chances of the cairn being of the same age as the standing stone are minimal; if it is the least bit older or younger it has to be irrelevant to the alignment hypothesis.
Kintraw should have an international reputation because of this and it is a real tragedy that its true signiﬁcance is ignored. The hill platform and the little standing stone above it should be a national monument; instead they are steadily disappearing under vegetation and among ever growing trees.
Dr Euan W. MacKie, MA (Cantab.), PhD (Glasgow), FSA
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Cite this article
Euan W. MacKie. The midwinter sunset alignment at Kintraw, Argyll – a response. Past Horizons. January 16, 2014, from http://www.pasthorizonspr.com/index.php/archives/01/2014/midwinter-sunset-alignment-kintraw-argyll