This all leads to the suspicion that here are signs of the very first activity of this sort on the site. The old ditch at this end could have been cut only after the ditches for crosswise viewing of Deneb and Betelgeuse were added. If the unsymmetrical solar arrangement ever made it seem desirable to view the Sun from a more central place, this would have demanded a higher altitude, easily arranged by building up the relevant façade posts. (For viewing along any of the set of three parallels, for instance, they would have been 2.9 m above ground level at mid-façade.)
One cannot be certain that there was no tree cover on the horizons needed for solar observations of the sort described, but both horizons are set by land fairly close by. It was shown from an analysis of molluscs sampled during the excavation that the immediate neighbourhood of the barrow was grassland, and that the mixed deciduous woodland that had covered the area had been cleared not long before. There are good reasons for thinking that the site was chosen for its solar properties: to bring the sighting lines to the solstices as near to parallels as possible, a higher altitude was needed towards midsummer setting than towards midwinter rising. The idea of perfectly reversible solstice alignments will be met with repeatedly elsewhere, but only at a much later date. Skendleby 2A is remarkable chiefly because it is such an early example of a carefully designed solar structure.
What of the implications of the mound, our Skendleby 2B? It should be plain enough that it brings alternative azimuths into the reckoning. The mound edges mentioned earlier provide much the same azimuth as the second crucial figure, and it seems that an effort was made to keep it, presumably not only for continuity’s sake in some abstract sense but because of its implications for observation of the Sun (the change in which is so slow that we can here ignore it). This, however, does not explain the direction of the very well defined line of stake posts and larger rubble running down the spine of the barrow.
Viewing across this would have provided azimuth 228.9°, which replaces the previous 233.9°, in our conjectural reconstruction of observing practice. Each of the options may be combined with a direction (48.9°) perpendicular to the spine of the barrow and the other related lines. In view of the barrow’s imperfections, it is unlikely that much more reliable data than this will ever emerge. Applying the usual method then yields a rather surprising result. The first option suggests viewing of the rising of Deneb and the setting of Aldebaran at an altitude of 15.76° around 3750 BC. The second option suggests viewing of the rising of Deneb and the setting of Betelgeuse at an altitude of 15.75° around 3730 BC. What is surprising is that the same mound could have been used to observe the setting of Aldebaran and Betelgeuse at more or less the same dates, as long as the directions of viewing were not too stringently set. (Aldebaran and Betelgeuse could have been seen setting across Skendleby 2A at points 5° apart in azimuth.) We have always assumed—for want of any sign of permanent direction markers—that observers after the initial architectural act had no precise means of knowing that the direction of view was strictly at right angles to any particular edge. It is for this very reason that a long barrow, used as explained, could have avoided becoming plainly outdated, in the minds of those who used it, for decades, even centuries. From the moment of foundation of a barrow, the stars were slowly shifting their places of rising and setting, but it would have been long before any but the expert realized the extent of the drift.
This is to assume that the barrow was used for ritual observation after its foundation, and that it was not just a question of ‘building the stars into the monument’ and then paying little attention to its properties. That the front ditch was still being used at Skendleby 2B to observe the setting Deneb, in exactly the same way as before, seems very likely, and the evidence is beautifully simple. The upper step on the inside wall of the ditch (Fig. 42) is just 32 cm above the lower, and this is exactly what would have been needed to change the viewing angle from 14.00° to 15.75°, at the distances in question, assuming that the property was to be retained whereby the relevant façade post came to the height of the observer’s eye. As for the character of what are here being referred to as steps, it is not to be supposed that they resemble those at St Paul’s. They were rough-hewn. They do seem to have been worn with some use, although very frequent use would surely have worn them more. These things have not been properly studied, since ditches have usually been regarded only as quarries for mound building. Either observation was done relatively infrequently, say by a single person at selected seasons, or the step was protected, perhaps by a wooden platform that it was meant to support. The second seems in any case not unlikely, just as ladders allowing entry to ditches in general would have been almost essential.
Skendleby 2B, with its long mound, perhaps built in more stages than suggested here, was thus brought into existence to redress the changes of the centuries. Some centuries later, and perhaps because of dissatisfaction with yet further changes nearby, a completely new barrow was built along similar lines, namely Skendleby 1. Very briefly, starting from azimuths 36.3° and 218.6°, one may conclude that the rising of Vega was seen from the southern side and the setting of Bellatrix from the other, both at altitude 17.4° around 3120 BC. It has to be said that there is another possibility, and that around the year 3550 BC the rising of Vega could have been combined with the setting of Betelgeuse, at altitude 19.0°. Other things being equal, the (later) option with lower altitude seems more fitting to the known scale and architecture of the ditches. Perhaps the two phases were both known; and it might even be prudent to assume that there was a still earlier ‘façade’ phase, as at the barrow nearby—in which case the labels Skendleby 1A, 1B, and 1C ought to be reserved. The chief reason for favouring the year 3120 BC (with the usual uncertainties) is that Skendleby 1 has provided two radiocarbon dates, equivalent to 3125 ± 225 and 3000 ± 300 BC (2460 and 2370, each ± 150 bc). The first of these could hardly be closer to our figure, although it would be unwise to claim better than an accuracy of a century or so in our own dating.
It seems that there were three centuries between Skendleby 2A and 2B. In a third phase, or even in a tail appended to 2B, it might have been used with Deneb still, but with Bellatrix in place of Betelgeuse—at the mound head around 3420 BC, say. Deneb would eventually have become unusable there. It is just conceivable that in due course Skendleby 2 passed into yet other phases. It would in this case have been built up slightly higher, making the viewing angles around 20°, and it could then have been used successively with Vega and Aldebaran (around 3310 and 3070 BC, in different ways) and Vega and Betelgeuse (around 3030 BC). On the whole it seems safer to put aside all these options, and to associate a highly specific structure only with a first probable use, that is, the use for which it seems to have been deliberately designed.
Did Skendleby 1 have any solar use? Its axis is less than 2° away from the required direction. There is an almost perfect alignment set by the revetting posts running from the northwest corner of the mound towards the right-hand (southwest) edge of the entire façade, but this part of the façade has been lost. The burial area might have been implicated in some alignment using the middle of the façade, but it is difficult to see how, and much less is on record concerning the fine structure of the façade here than at the other barrow.
Most of the fourteen radiocarbon dates associated with Skendleby 2 provide support for the gamut of astronomical dates offered here. The oldest, for a piece of façade charcoal, was equivalent to about 4250 ± 100 BC (1965 ± 80 bc). This was presumably large and very old timber, and is recognized as anachronistic. There followed three highly consistent specimens, of oak charcoal and antler, the oldest being 3910 ± 120 BC (3155 bc), and so belonging to phase 2A. One item of charcoal from the north burial post pit (3790 ±