The Dorset Cursus and the midwinter sun: a LiDAR test

This post is the companion to the short film Ten kilometres for one sunset?, which tests a fifty-year-old astronomical claim about the Dorset Cursus against modern LiDAR. The method, numbers and caveats follow.

Fly the cursus yourself: Dorset Cursus 3D LiDAR flyover.

The monument

The Dorset Cursus is a pair of parallel banks with outer ditches running for just over 6¼ miles, nearly 10 km, across Cranborne Chase, from Thickthorn Down in the south-west to Martin Down in the north-east (RCHME 1975; Dorset HER MDO5608). It was built in two parts. The first, the Gussage cursus, ran from Thickthorn to a terminal on Bottlebush Down; the second, the Pentridge cursus, continued it on a slightly different alignment to Martin Down. Measured along the published points, the two are 5.65 km and 4.33 km long. Radiocarbon dates span the second half of the fourth millennium BC (Bowden et al. 1983; Barrett, Bradley & Green 1991). For most of its length it survives only as a cropmark or soilmark; the ends at Thickthorn and Martin Down remain as earthworks.

Long barrows lie beside it, inside it and in its banks. On Gussage Hill one lies across the interior, at right angles to the banks: a mound 155 ft long, 65 ft across and up to 10 ft high (RCHME 1975; Dorset HER MDO5615).

The Dorset Cursus on EA 1 m LiDAR, from the south-east. Height ×1.5.

The claim

Penny and Wood (1973) proposed that an observer at the Bottlebush terminal of the Gussage cursus would see the midwinter sun set behind the Gussage Hill long barrow. Barrett, Bradley and Green (1991) accepted this as the most plausible of Penny and Wood's alignments. It has since become the standard astronomical reading of the monument.

The test

The Environment Agency's LIDAR Composite DTM at 1 m (2022) covers the whole cursus. The observer is placed 30 m inside the Bottlebush terminal (RCHME SU 01581566) on the line of the Gussage cursus, at E401558 N115639, with the eye 1.6 m above the ground. The barrow mound is located directly in the DTM: its summit stands 3.1 m above its surroundings, and the part higher than 0.6 m is 43 m long on a bearing of 143°, matching the RCHME description.

From the observer the barrow is 2.89 km away on a bearing of 231.2°; the mound spans 230.8° to 231.7°. Sight lines are traced across the DTM out to 8 km with the curvature of the earth and terrestrial refraction (coefficient 0.13) included.

Section along the sight line from the Bottlebush terminal. The barrow is the skyline; the ground beyond stays below the line. Height exaggerated as marked.

The barrow is the skyline. On bearings from 224° to 238° the horizon is the Gussage Hill ridge, 2.83 to 2.95 km away, and the mound lifts it from about 0.24° to 0.29° above level. Nothing further away shows above it.

The sun. In 3300 BC the obliquity of the ecliptic was 24.05° (Laskar 1986), so the midwinter sun's declination was −24.05°. At latitude 50.93° N, with standard refraction at the horizon's altitude, the last gleam of the sun, its upper limb touching the skyline, goes down on a bearing of 230.60°. Moving the date to 3500 BC or 3000 BC shifts this by less than 0.05°.

The skyline from the middle of the Bottlebush terminal at true angular scale, with the midwinter sun of 3300 BC at three moments of its setting. The last gleam goes down just south of the mound.

From the middle of the terminal it just misses. The last gleam goes down 0.20° south of the mound's south-west end, about 10 m at the distance of the barrow. The sun's disc is 0.53° across, so the miss is less than half its width.

From the north-west half it works. Moving across the cursus changes the barrow's bearing by about 0.02° for every metre. From anywhere between 10 m and 55 m north-west of the axis, which is the north-west half of the terminal, the last of the midwinter sun goes down behind the mound.

The Bottlebush terminal on LiDAR local relief. Gold: the last gleam goes down behind the barrow. Blue: it goes down just beside it. Banks as traced on the flyover.

What could move it

• Refraction. Near the horizon in winter it varies from night to night; a change of 30% moves the last gleam by about 0.27°, more than the miss from the middle of the terminal.
• The terminal. The Gussage terminal bank on Bottlebush is ploughed. Its position comes from an eight-figure RCHME grid reference, and the axis there from the line between published points, not from surviving banks. Either can shift the zone by several metres.
• The barrow. The DTM records the mound as it is now, ploughed and eroded. A taller mound would widen the zone, not narrow it.
• Trees. Neolithic woodland on Gussage Hill, if any, is unknown and not modelled.

Conclusion

The 1973 claim survives a test its authors could not run. The Gussage Hill long barrow is the skyline from the Bottlebush terminal, and the midwinter sun of the late fourth millennium BC sets behind it when seen from the north-west half of the terminal, and just beside it from the south-east half. Whether the builders intended this cannot be settled from the ground.

How the line is drawn. No complete survey plan of the cursus is published. The banks on the flyover run between the published positions of the terminals and of points along the line (Historic England 1002785; RCHME long barrow 14, SU 011152, SU 01581566, SU 025169, SU 04051920), moved onto the ridges where the LiDAR still shows them, and left on the straight line between points across ploughed gaps. The code for the test is in the film's folder on GitHub (align.py, sens.py, diagrams.py).

References

• Atkinson, R. J. C. 1955. The Dorset Cursus. Antiquity 29, 4–9.
• Barrett, J., Bradley, R. & Green, M. 1991. Landscape, Monuments and Society: the prehistory of Cranborne Chase. Cambridge University Press.
• Bowden, M., Bradley, R., Gaffney, V. & Mepham, L. 1983. The date of the Dorset Cursus. Proceedings of the Prehistoric Society 49, 376–379. doi:10.1017/S0079497X00008069
• Dorset Historic Environment Record: MDO5608 The Dorset Cursus; MDO5615 Long barrow on Gussage Hill.
• Historic England list entry 1002785, Western end of Dorset Cursus.
• Laskar, J. 1986. Secular terms of classical planetary theories using the results of general theory. Astronomy and Astrophysics 157, 59–70.
• Loveday, R. 2019. Neolithic cursus monuments. Prehistoric Society, Neolithic factsheet 8.
• Penny, A. & Wood, J. E. 1973. The Dorset Cursus complex: a Neolithic astronomical observatory? Archaeological Journal 130, 44–76.
• RCHME 1975. An Inventory of Historical Monuments in the County of Dorset, Volume V: East Dorset. HMSO.

LiDAR: Environment Agency LIDAR Composite DTM 1 m, 2022. © Environment Agency copyright and/or database right 2022. Open Government Licence v3.0. Flyover, diagrams and analysis: T. Daw. Music in the film: original.

Eighty metres up: North Devon's erratics and the ice route to Stonehenge

This post is the companion to the short film Eighty metres up. In under three minutes the film sets out why the erratic boulders of North Devon matter to the claim that ice carried the Stonehenge bluestones to Salisbury Plain, and what they actually show. The full argument, with sources, follows.

The claim

Glacial transport of the bluestones needs Irish Sea ice that was not merely present in the Bristol Channel but standing high on the land, high enough to override the coast and carry on towards Wiltshire. The case for that has leaned on erratics. One abstract puts it this way: "of the scores of known glacial erratics on the shores of the Bristol Channel, many are found at altitudes in excess of 100m" (John 2024, ResearchGate abstract to his Quaternary Newsletter 162 article; the sentence does not appear in the article itself, as set out in The myth of Bristol Channel high-level glacial erratics).

South of the Channel, North Devon is where such evidence would have to be found. Three bodies of evidence there bear on the question: the shoreline erratics, the Fremington clay, and a handful of claimed high-level sites, of which the Ramson Cliff boulder is the last and the most cited.

The shoreline band

The Saunton–Croyde erratics, Madgett & Inglis (1987), plotted from their grid references

Far-travelled boulders have been reported at the foot of the Saunton cliffs since 1837. Madgett & Inglis (1987) catalogued 37 in the Saunton–Croyde area (listed with grid references in the North Devon erratics master catalogue). Thirty-six of them lie on the foreshore, the raised shore platform or the raised beach, all below about 30 m OD. Every erratic reported up to 1969 lay at the base of the cliffs. The largest is the granulite gneiss near Baggy House at Croyde known as the '50-tonner' (No. 2, 420 × 220 × 200+ cm, first recorded by Hughes in 1887), resting on the planed shore platform; its weight "has been estimated to be 50 tonnes" (Bennett et al. 2024, p. 91).

The '50-tonner' granulite gneiss erratic at Croyde. Archive photograph.

These boulders are genuinely far-travelled and they matter. Their distribution is the evidence. Stephens (1966) pointed out that the largest are confined to a narrow coastal band within reach of storm waves: a selective distribution that is hard to explain by an ice sheet burying the ground, and easy to explain by boulders grounded from floating ice at a former shoreline. Scourse et al. (2024) have since supplied a dated mechanism. Early in the last cold stage (Marine Isotope Stages 4 and 3), ice-loaded crust held relative sea level high while calving ice margins still existed offshore, so floating ice could raft material onto the southern shore platforms. Bennett et al. (2024, p. 91) set out the same alternative, that the platform erratics "were delivered by icebergs calved from glacier ice farther north", and conclude that "both modes of transport (ice-rafting and glacial transport)" may have been involved in the South-West. The shoreline band is the signature of ice that reached the coast, not of ice that climbed it. The argument is set out more fully in Two boulders fewer and Thinking three dimensional.

Floating ice grounding on the shore platform at a high relative sea level. Diagram, not to scale, after Scourse et al. (2024).

The Fremington clay

Boreholes along the Higher Gorse–Roundswell line. Red: lake clay; gold: uncertain; grey: head on the ridge. From BGS borehole logs.

The red potter's clay of Fremington, near Barnstaple, was described as boulder clay by Maw in 1864 and for a century was read as till from an Irish Sea ice sheet. Bennett et al. (2024, p. 87) still call these deposits "the only widely (though not universally) accepted evidence that glacier ice ever reached the peninsula". The borehole record points elsewhere. The Brannam campaign logs (BGS SS53SW62–79) and later holes confirm fine lake clay only at low levels: its base and the underlying gravel lie at about 15–28 m OD, the highest confirmed clay tops at 31.7–32.8 m OD, so no higher than about 33 m, and there is none south of the Hele–Bickington ridge. On the ridge itself, at 38–40 m OD, the clayey material is head, not lake clay. That fits the lake surface of about 30 m OD that Edmonds inferred, as reported by Bennett et al. (2024, p. 88). The clay records a modest lake ponded in the Taw–Torridge estuary behind an ice and outwash dam at the coast, not a till sheet laid by grounded ice overriding Devon to 80–90 m. The boreholes are mapped in the Fremington Clay gazetteer; the analysis is in New borehole analysis sharply constrains the Fremington Clay and Caution in attributing the Fremington Clay Series to Irish Sea glaciation.

The high-level claims, checked

The heights below are those given by the proponent of glacial transport in his own table of erratics on or near the coasts of Devon and Somerset. Each was checked against the published record in The myth of Bristol Channel high-level glacial erratics and the fuller critical analysis.

Site	Claimed height	Finding
Lundy	138 m	Local Lundy granite moved about on the island, not far-travelled erratics (Rolfe et al. 2014). Carr reads them as residual boulders from two-stage weathering rather than glacially transported.
Shebbear (Devil's Stone)	150 m	A sarsen, a local silcrete on or near its parent duricrust: not a travelled stone (The Shebbear erratic sarsen).
Ilfracombe–Berrynarbour plateau	150–175 m	Rests on a single sentence in Campbell et al. (1998, p. 202) citing "erratic material"; no erratic boulder is recorded.
Court Hill	68 m	No relevant erratic boulders in the GCR site account.
Nightingale Valley / Portishead Down	85 m	No relevant erratic boulders in the GCR site account.
Westonzoyland; Kenn	10 m; 7 m	Within or near tidal range: not high-level.
Ramson Cliff, Baggy Point	80 m	See below.

Ramson Cliff: the emplacement problem

The Ramson Cliff erratic beside the coast path, 2025. Photo: T. Daw

The Ramson Cliff erratic is a 378 kg block of altered epidiorite (105 × 55 × 38 cm; Madgett & Inglis 1987, No. 8) now lying beside the coast path at about 80 m OD on Baggy Point. It had been treated as decisive. Bennett et al. (2024, p. 91) wrote that "an isolated block of epidiorite was found at about 80 m OD on Baggy Point promontory [SS 4356 4070] by Madgett and Madgett (1974) which can only have been emplaced by an ice sheet." They qualified it at once: "Whilst this implies ice-sheet transport, it is important to consider the role of tectonic uplift of the region early in the Pleistocene." It has also been cited in support of glacial transport of the bluestones (John 2024).

The question is how the boulder came to be where it was found. Daw, Ixer & Madgett (2026) went back to the original thin section, the archive and the correspondence:

• It was first recorded in 1969, standing upright in the middle of a pasture field on the crest of Baggy Point. It does not appear on earlier maps or aerial photographs.
• In the early 1970s the field was ploughed; the boulder was knocked over and then dragged to the field edge, where it lies now.
• It is angular and rough-surfaced, with none of the abrasion of the shoreline boulders.
• It is the only claimed erratic on the south shore of the Bristol Channel above about 30 m OD, with no supporting deposits, striae or erratics at intermediate heights.

Ramson Cliff erratic, thin section. Madgett & Madgett.

The petrography adds to the emplacement problem. A second thin section, cut from the original hand specimen and described by Rob Ixer in September 2026, confirms the published description. The rock is a highly altered ophitic microgabbro with relict clinopyroxene, no olivine and no quartz; the secondary minerals are brown-green hornblende and later colourless-to-green actinolite, with minor chlorite, epidote and clinozoisite. That assemblage matches the outer aureole of the Dartmoor granite and is consistent with Cornubian contact metamorphism. It does not match the Welsh Ordovician metadolerites on the Irish Sea ice route. A Scottish source cannot be excluded on the amphibole evidence alone.

Irish Sea ice came from the north. Dartmoor lies inland, to the south. A Cornubian source does not prove that people moved the stone, but it makes a lone high-level glacial drop even less likely. An angular block of probably local greenstone, standing upright, unworn, undocumented before 1969 and alone at its height is better read as a manuport, perhaps a standing stone, than as proof of an ice sheet 80 m above the sea.

Statistically it is also an outlier. Of 49 recorded erratic heights in the area, about 86% lie between 5 and 25 m OD; the 80 m value is flagged by the interquartile-range test, the z-score (z = 5.92), Grubbs' test and Dixon's Q test.

What is left

With Ramson Cliff and Shebbear set aside, there is no demonstrated far-travelled boulder above the coastal zone of North Devon, and the claimed high-level sites further east do not survive inspection either. Every proven far-travelled boulder south of the Channel sits at or near the shore. Irish Sea ice reached the coast; nothing shows that it climbed inland, let alone that it went on to Salisbury Plain.

Caveats. This is the better-supported position, not an agreed one. Bennett et al. (2024, p. 91) had previously read the Ramson Cliff boulder as glacial, though with the uplift caveat noted above; Daw, Ixer & Madgett (2026) was written in response. Croot et al. (1996; reviewed by Bennett et al. 2024, p. 88) concluded that the Fremington Clay Series, though probably glaciolacustrine, was overridden by glacier ice. Bennett et al. themselves allow that the Fremington till and gravels may have been deposited near the ice limit "directly or indirectly (i.e., as ice-rafted debris)" (p. 87). Low-level grounded ice reaching about the present coastline remains possible for North Devon, and local glaciation in Devon is not challenged. What it removes is the evidence that was said to require thick ice high on the land.

Notes on the film. The coastline on the maps is drawn from ONS administrative boundaries (Open Government Licence). The red dots are Madgett & Inglis (1987) Nos 1–7 and 9–37, plotted from the catalogue grid references. Claimed sites are plotted from published grid references where they exist (Court Hill ST 473 723, Nightingale Valley ST 450 752, the Devil's Stone SS 4388 0925, Ramson Cliff SS 4356 4070); Lundy and the Ilfracombe plateau are approximate. The Fremington section is redrawn from the borehole data in the Fremington Clay gazetteer. The Croyde photograph is an archive image; the thin section is Madgett & Madgett's. Ramson Cliff and bluestone photographs: T. Daw. Music: original.

Related: A review of the Ramson Cliff erratic · Stonehenge glacial transport theory takes another major hit · Outwash fan-heads, composite dams, and the Fremington lake level · The tangible evidence from the Fremington clays · The demise of the glacial transport theory

Sources

• Bennett, J.A., Cullingford, R.A., Gibbard, P.L., Hughes, P.D. & Murton, J.B. (2024). The Quaternary geology of Devon. Proceedings of the Ussher Society 15, 84–130.
• Campbell, S., Hunt, C.O., Scourse, J.D., Keen, D.H. & Stephens, N. (1998). Quaternary of South-West England. Geological Conservation Review Series 14. Chapman & Hall / JNCC. Chapter 7 (PDF)
• Carr, S. Landscape evolution of Lundy. University of Cumbria repository
• Croot, D.G., Gilbert, A., Griffiths, J. & van der Meer, J.J.M. (1996). The character, age and depositional environments of the Fremington Clay Series, North Devon. Quaternary Newsletter 80, 1–15.
• Daw, T., Ixer, R. & Madgett, P. (2026). A review of the Ramson Cliff erratic: evidence of high-level ice flow? Quaternary Newsletter 167, 13–19. doi:10.64926/qn.20517
• Daw, T. (2024). The myth of Bristol Channel high-level glacial erratics. sarsen.org, 16 December 2024.
• Daw, T. (2025). Critical analysis of claims regarding high-level glacial erratics in the Bristol Channel and the implication for the glacial transport theory of Stonehenge bluestones. Academia.edu.
• Daw, T. (2026). New borehole analysis sharply constrains the Fremington Clay. sarsen.org, 29 April 2026.
• Daw, T. (2026). North Devon glacial erratics: a master catalogue. sarsen.org, April 2026.
• Daw, T. (2026). Thinking three dimensional. sarsen.org, 14 May 2026.
• Daw, T. (2026). Two boulders fewer: North Devon's erratics now point to ice rafting, not override. sarsen.org, 31 May 2026.
• Daw, T. (2026). Ramson Cliff erratic: a second thin section still points Cornubian, not glacial (petrography by R. Ixer). sarsen.org, 21 September 2026.
• Daw, T. Fremington Clay gazetteer (boreholes, outlines and sections; CC BY-SA 4.0).
• John, B. (2024). An igneous erratic at Limeslade, Gower, and the glaciation of the Bristol Channel. Quaternary Newsletter 162; ResearchGate abstract: publication 381775577.
• Madgett, P. & Madgett, R. (1974). High level erratic on Baggy Point. Quaternary Newsletter 14, 1–2.
• Madgett, P.A. & Inglis, A.E. (1987). A re-appraisal of the erratic suite of the Saunton and Croyde areas, North Devon. Transactions of the Devonshire Association 119, 135–144. PDF
• Maw, G. (1864). On a supposed deposit of boulder-clay in North Devon. Quarterly Journal of the Geological Society of London 20, 445–451.
• Rolfe, C.J., Hughes, P.D. & Brown, A.G. (2014). Timing of the maximum extent of Late Pleistocene glaciation in NW Europe: evidence from Lundy. Journal of the Lundy Field Society 4, 7–18. PDF
• Scourse, J.D. et al. (2024). The timing and magnitude of the British–Irish Ice Sheet between Marine Isotope Stages 5d and 2: implications for glacio-isostatic adjustment, high relative sea levels and 'giant erratic' emplacement. Journal of Quaternary Science. doi:10.1002/jqs.3611
• Stephens, N. (1966). Some Pleistocene deposits in North Devon. Biuletyn Peryglacjalny 15, 103–114.

Stonehenge Landscape Flyover

 Fly over the Stonehenge landscape, and watch the sun rise in 2500 BC

I've put a new tool online: a 3D flyover of the Stonehenge landscape, not just Stonehenge but also Woodhenge and the new Bulford post alignment. It runs in your web browser, there's nothing to install.

https://timdaw37.github.io/stonehenge-landscape-flyover/

The ground is built from Environment Agency lidar, with Ordnance Survey terrain for the distant hills and the rivers. On it sit the monuments from Historic England's mapping. Stonehenge has its stones on their surveyed positions, Woodhenge has its post rings from Maud Cunnington's 1929 plan, and there's the newly found pair of posts at Bulford. A period slider lets you strip the landscape back from the Early Bronze Age to the Mesolithic and watch it fill up again.

You can fly with the mouse, keyboard or the touch pad in the bottom right corner, which also works on phones and tablets. Double-click anywhere to fly there, or press P for a plan view.

The part I find most useful is the alignment check. Choose a site (Stonehenge, Woodhenge or the Bulford post axis), then an event such as midsummer sunrise, midwinter sunset or a lunar standstill, and pick first gleam, half disc or full disc. It works out where and when the sun or moon clears the real skyline, as seen from that spot, for 2500 BC or any year you choose. It then puts you there, looking at it. A Details button gives the full workings: the true azimuth, the time, and the horizon that was used.

Everything behind the site is open on GitHub, so anyone can take it and build on it:

https://github.com/TimDaw37/stonehenge-landscape-flyover

It's shared under a Creative Commons licence (CC BY-SA 4.0). Use it, change it, and add your own sites or ideas, as long as you credit where it came from and share your version in the same way. 

It's still a work in progress. If you spot anything wrong, from a misplaced monument to a sunrise that looks off, please let me know in the comments.

Historic England’s Vanishing Archive

Historic England’s photos didn’t vanish. SmartFrame did. Then they broke their own links.

Not just the aerials. The lot.

Historic England still holds the negatives, the prints and the scans. What the public lost, in early September, is the ability to look at them. The official notice, last updated 25 September 2026, is admirably blunt:

“This is because the third-party service that we use to display Archive images on our website has ceased trading and entered administration.”

The 11 September version named the damage:

“This means that images are not currently available across Archive records and the Aerial Photo Explorer. Images of England images are also not available on the National Heritage List for England.”

Ground shots, architectural stills, catalogue images, aerials, and the old Images of England pictures on list entries. All of it.

The third party, named by Michael Pritchard on British Photographic History, is SmartFrame Technologies Limited. Henry Page and Shaun Walker of Mercer & Hole were appointed administrators on 26 August 2026. BusinessCloud reports assets of about £2.3m, cash of £182k, liabilities of £1.7m, and a firm that “failed to secure further funding.”

SmartFrame did not store the Archive. It streamed it: zoom, captions, right-click protection, screenshot blocking, anti-scrape. A public body wrapped a national collection in a start-up’s DRM. When the start-up died, the pictures went with it.

Confirmed down, because HE said so:

• images on Archive records
• the Aerial Photo Explorer
• Images of England photographs on the National Heritage List

Not named in the photo notice: England’s Places; list descriptions; the Swindon search room; copy orders. The early Aerofilms set is still on Britain from Above.

HE first promised previews “in several weeks.” The 25 September update is cooler:

“We are hopeful that smaller preview images will be available on the website by 2 October… 400 x 400px image thumbnails… a longer-term solution… is likely to take many months to implement.”

And, for listed-building photos on the List:

“Images of England images on the National Heritage List for England are not being replaced at this time.”

Please do not email the Archive team. The page says so. Visit, or order a copy.

In 2022 SmartFrame called Historic England “a great example” of its interactive frames. Critics noted the same wrapper was stopping people saving RAF verticals whose Crown copyright had already expired. HE later said, on X, that it had spent £65,830 net on the licence from 2020/21 to 2023/24, putting over a million images behind it, and that it was “not an income generation tool.” In 2024 there was another £41k tender. Call it a little over £100,000 to stop people saving pictures a public body was already putting online.

The comparison is the London galleries. Douglas McCarthy’s FOI figures show the National Gallery Picture Library paying a £100,000 internal fee to exist, then posting net losses of £37,575 and £47,615 in two of the last three reported years. Andrea Wallace’s 2022 UKRI report was blunter: licensing images of public-domain works “does not appear to be a present or future revenue scheme with potential for growth, and is actually a financial burden on the GLAM sector.” Tate, which also bought SmartFrame in 2022 for Tate Images, at least has living artists to clear. Historic England was spending six figures to wrap photographs the taxpayer had already paid for. Then the wrapper died, and the public cannot see them at all.

CEO Rob Sewell wrote that SmartFrame “had all the hallmarks of a global disruptor” and was “seeking to restore industry value to the photography market.” It signed football clubs and picture agencies. It did not sign a plan B for a statutory archive.

Then they did it again to the words.   

UPDATE 29 Sept 2026 - this problem seems to have been fixed

On 16 September 2026 Historic England switched on a new Heritage Gateway and killed the old one. For twenty years the stable record URL was:

https://www.heritagegateway.org.uk/Gateway/Results_Single.aspx?uid=219528&resourceID=19191

That path is dead. No redirect to the record. heritagegateway.org.uk dumps you on a search box. PastScape hob.aspx?hob_id= went the same way years ago and now has nowhere to land.

Volunteer sites took the hit first: Megalithic Portal, Megalithomania, county walk pages, teaching lists — anything that treated a Gateway UID as a permalink. Annoying. Expected, if you hitch your wagon to someone else’s CMS.

Then look at HE’s own map.

The Aerial Archaeology Mapping Explorer still draws. The banks and ditches are on the Open Data Hub. What died is the click. Every grey monument pop-up was supposed to open the full record. HE baked the old Gateway URLs into the GIS. The published schema says so, in words a child could read:

• HE_URL1 to HE_URL5 — “URL link to the relevant Historic England record in Heritage Gateway”
• HER_LINK_1 to HER_LINK_25 — the same for the local HER
• HER_PREF_REF — “alternative HER UID that is used to create the Heritage Gateway URL”

Thousands of those strings are sitting in a national dataset HE still publishes. The Mapping Explorer landing page still tells you a click “will take you to the Heritage Gateway” and still points at heritagegateway.org.uk/gateway. They relaunched the catalogue and left their own map wired to the corpse. Not a third party this time. Not SmartFrame. Them.

A public body spent six figures locking pictures, then cancelled the only stable identifier the rest of the web — and its own aerial mapping tool — had been told to use. HIAS Principle 5 was “a national overview should continue to be delivered online through the Heritage Gateway.” Principle 6 was that knowledge “should not be at risk of loss, fragmentation… or system obsolescence.” They managed both in a fortnight.

Let the photographs free. Out of copyright: a JPEG. Need a tidy file for print: charge for the file, not for the looking. And if you change a national URL scheme, redirect the old ones. A statutory archive is not a Premier League still, and a mapping explorer with thousands of dead links on the organisation’s own website is not a launch.

Bloodlines in the barrows

Diachronic reuse of Neolithic burial monuments: What the Kinship Test Found

After my posts (https://www.sarsen.org/2026/09/borrowed-tombs-or-ozymandias-in-wessex.html and  https://www.sarsen.org/2026/08/a-stranger-in-family-grave.html) on Vuković et al. 2026, a query arose that the paper's main text doesn't answer. Did the study test whether the people buried at each site were related to each other, especially the three infants buried together in the Fir Tree Field pond barrow? And what exactly were the Monkton four: all siblings, or a mother and three children? The genetics finds two boys among the children, where the bones suggested one. Children can't be reliably sexed from the skeleton, so this is a correction rather than a surprise.

UPDATE from Martin Green: " the adult female at MUW97 was F23c - so they are a mother and 3 children"

The main text only has room for Monkton. The answers are in the supplement. The kinship test found one first-degree family, one third-degree pair, and no link across the gap at the three reused monuments. The triple infant burial turns out to be the most surprising result of all. Figures are from Table 1 and Supplementary Data Files 9 and 10, unless noted.

How the test was run

READv2 was run on pairs, with the Neolithic individuals kept apart from the later ones so the baseline is not mixed. A first-degree pair is a parent and child, or full siblings. The authors specify a pair as siblings only where the overlap is at least 40,000 markers. Lower pairs are printed and not used for that call. The Neolithic pairs are Supplementary Data File 9. The later pairs are Data File 10. There is no published pair that joins an early burial to a later burial at the same site.

Monkton-up-Wimborne

Four people in one oval grave, dates overlapping 3364–3093 BC. The main text treats two arrangements as the most parsimonious: all four full siblings, or a mother of 30–45 with three children of about 5, 9 and 10. The site note says a woman of about 30, two girls of 5–10 and a boy of about 9. Genetic sex does not match that reading of the bones. Table 1 has two males and two females.

ID	Skeleton	Date (95.4%)	Coverage	Sex	mtDNA	Y
muw002	F23B	3364–3101	0.34×	XY	K1a+195	I2a2a
muw003	F23C	3363–3101	0.11×	XX	K1a	–
muw001	F23A	3357–3093	0.78×	XY	K1a+195	I2a2a1a1a2
muw004	F23D	3340–3096	0.41×	XX	K1a+195	–

All six pairs are called first degree. Two clear the 40,000-marker line, and both are called full siblings: muw001–muw002 (42,708 markers, kinship 0.24) and muw001–muw004 (49,696, kinship 0.25). The other four are first degree on less data, and the supplement will not say sibling rather than parent for those.

Pair	Markers	Call	Kinship
001–004	49,696	First degree, siblings	0.25
001–002	42,708	First degree, siblings	0.24
002–004	27,645	First degree	0.24
001–003	15,849	First degree	0.26
003–004	10,282	First degree	0.21
002–003	8,788	First degree	0.25

So muw001, muw002 and muw004 are one generation. muw001 and muw002 share I2a2a; muw001 is called to a finer branch. Three of the four are K1a+195. muw003 is called only K1a, on the lowest coverage and the lowest mitochondrial coverage (7.25×, against 37–107× for the others). That is a shallower call, not a second maternal line. The paper's statement is that all four lie within K1a.

muw003 is in every pair below 16,000 markers. She is the person the test cannot place. If she is the adult woman, a mother and three children fits, and the three children are already the sibling set. If the adult is muw004, the test has already called her a full sibling of muw001, so she is an older sister, and muw003 is another sibling rather than the mother. The sample list is F23A = muw001, F23B = muw002, F23C = muw003, F23D = muw004. Which of those four skeletons is the adult is not in the paper. That is the only fact still needed.

The later man is not in that test. muw005, 1519–1321 BC, coverage 0.14×, is male, mitochondrial haplogroup H, Y-haplogroup R1b1a1a2. No READv2 pair links him to the four. The runs were split by period. The paper calls him unrelated on ancestry, not on a kinship coefficient. He was laid on the surface of the partly silted central pit, not in the family's grave, and covered with a small flint cairn. His mitochondrial haplogroup is not theirs, and neither is his Y line.

Fir Tree Field pond barrow

Fourteen centuries later and not far away, on the same stretch of Cranborne Chase, the question is reversed. At Monkton the bones suggested a family and the genetics confirmed it. At Fir Tree Field a triple burial of infants looks like a family, and the genetics says otherwise.

Five individuals, all Early Bronze Age. The site note identifies four of them. F14a, F14b and F14d are the three infant inhumations in F14. F6 is a separate infant, 18 months to 2 years, extended, with a Food Vessel. F27 is in the sample list and not in that note.

ID	Feature	Who	Date (95.4%)	Sex	mtDNA	Y
dfb004	F14d	Infant	2008–1748	XY	U5b2a4	R1b1a1a2a1a2
dfb002	F6	Infant, 18 months–2 years	1955–1781	XY	I1a1	R1b1a1a2a1a2
dfb005	F27	Not described in the site note	1920–1769	XX	U5b2a1a2	–
dfb003	F14b	Infant	1886–1750	XY	T2b2b	R1b1a1a2
dfb001	F14a	Infant	1882–1745	XY	H1b	R1b1a1a2

UPDATE from Martin Green: "F27a was in a separate grave pit on the northern edge (one of only two burialsin that area), the other an unaccompanied cremation in a funnel-shaped pit.
F27a contained an infant between 0-2 months
The grave pit had partly cut one of the Beaker pits (F27) also in that area."

The five mitochondrial haplogroups are five different ones. That excludes a mother and child, and siblings through the mother, among these five. The three in F14 are unrelated to each other: kinship 0.01 (F14a–F14b, 21,445 markers), 0.02 (F14a–F14d, 20,579) and 0.03 (F14b–F14d, 25,940), against about 0.25 for a first-degree pair. A brother or a parent inside the triple would have shown. One was called at Monkton on fewer markers than any of these.

The relationship that was reported is not inside the triple. dfb002 (F6) and dfb004 (F14d) are third degree: 39,862 markers, kinship 0.06. Same Y-line, R1b1a1a2a1a2, and different mitochondrial haplogroups, I1a1 and U5b2a4. The supplement calls it a distant paternal relative. Between two infants, third degree most simply means first cousins, children of two brothers, though the test cannot say which third-degree relationship it is. The authors treat it as one of the two post-Neolithic results that clear their reporting line. The other is not a relative: cfa001 and a previously published Canada Farm individual are the same person sampled twice.

The other two boys in F14 are called only to R1b1a1a2, the clade above that longer type. That can be as far as their data go. It is not a second reported relationship. F27 is unrelated to the other four on the pairs that could be read. She is the one individual in the barrow without a described context: female, dated with the others, with ordinary Bronze Age ancestry, but not in the site note, so her age, grave and position are unknown here. Her mitochondrial haplogroup, U5b2a1a2, sits on the same U5b2 branch as the F14d infant's U5b2a4, but on a different twig. That shared maternal ancestry lies far too deep to count as family.

Across the gap

Which leaves the question the paper was built around. At the three monuments where a later burial sits in an older one, the later person does not share a mitochondrial haplogroup with anyone earlier sampled there.

Site	Earlier	Later
Monkton-up-Wimborne	Four, all within K1a, 3364–3093 BC	muw005, H, 1519–1321 BC
Sisters Long Barrow	K1a4a1b, J1c3, H4a1a1, 3888–3527 BC	slb016, H1ak1, 1534–1436 BC
Sale's Lot	lot005, K1b1a1, 3946–3654 BC	lot001, H6a1b, 2622–2467 BC

No READv2 pair was published between the early and late individuals at these sites. A first-degree link across those gaps was not a plausible thing to find, and was not tested in the published runs. A maternal line from the particular people sampled is ruled out by the haplogroups. A paternal line is ruled out only at Monkton, where both the early boys and the later man have Y data and they differ (I2a2a against R1b). At Sisters and Sale's Lot the later burials are women, so there is no Y line to compare. Descent from Neolithic Britain in general is a question for the ancestry models, and for my earlier post.

Within the whole set, the only kinship READv2 reports between different people is the Monkton cluster and the one third-degree pair at Fir Tree Field. Everywhere else the within-site pairs are unrelated, or the overlap was left unused.

What it adds up to

So, to answer the query: they did look. The kinship test was run on everyone with enough data, and it simply found very little. At Monkton it found the family everyone expected, and it is one fact away from saying which family. If the adult woman is F23C, she is the mother of three full siblings. If she is F23D, all four are siblings. Someone with the skeletons can settle that.

At Fir Tree Field it found something nobody expected. The three infants laid together in F14 were not brothers, and not close kin at all. Whatever put them in one grave, whether a shared death, a shared season or a shared rite, it was not close family. The one family thread in the barrow runs between graves instead: the infant in F6 and one of the F14 three were cousins, or something like it, through their fathers. The pond barrow held a lineage, loosely, but not a household.

And across the gap, nothing, which is what anyone should have expected. Kinship tests find parents, siblings and cousins. They cannot bridge twelve centuries, let alone twenty-two. The strangers in the old graves were not the builders' grandchildren. Whether they were, in some remote and untraceable way, their descendants is a question kinship tests cannot answer.

---

Vuković, N. et al. (2026). Diachronic reuse of Neolithic burial monuments by Bronze Age newcomers in Southwestern Britain. Scientific Reports 16:26819. doi:10.1038/s41598-026-66094-z. Table 1; p. 6; site notes for Monkton-up-Wimborne and Fir Tree Field pond barrow; Supplementary Data Files 9 and 10. The position of muw005 on the surface of the infill is from the excavator's account.

Borrowed tombs, or Ozymandias in Wessex?

A paper in Scientific Reports gives the genomes of thirty people from twelve burial places in Gloucestershire and Dorset, buried between about 3800 and 1400 BC. Those laid down before 3000 BC belong with the Neolithic farmers who raised the long mounds. Those laid down from about 2550 BC are a different people, with the ancestry that comes into Britain among the Beaker dead. At three of the old monuments the later dead were put into earth their own ancestors had not built. I looked at the science: https://www.sarsen.org/2026/08/a-stranger-in-family-grave.html but there is a another puzzle.

Continued use is not the puzzle. The puzzle is what the use was for. It may be a tradition, taught on, even after the bloodline has changed. Or it may be Shelley's traveller, who comes on "two vast and trunkless legs of stone." He reads the boast on the pedestal. He does not inherit the kingdom. 

The graves look like that second kind of use, and the years are the reason. At Sale's Lot a woman was laid in a mound twelve centuries after the people who built it. At Monkton-up-Wimborne a man was set down in an old hollow seventeen centuries after the family buried there. At Sisters Long Barrow a young woman went into a mound twenty-two centuries after the men who lay in it. Not a rite kept up year by year. Two moments, far apart: one around 2500 BC, as the Beaker dead were beginning to arrive, and one around 1500 BC, when axes were being carved on the Stonehenge sarsens. The later dead were mostly not the builders' descendants. They wanted the places. Wanting a place is what the traveller does.

Beacon Hill, south of Newbury, is the same act with the paperwork kept. The hill was already an Iron Age fort, and the new grave was cut into it some two thousand years after the rampart. There were older barrows on it, it had carried a beacon, and skeletons had been dug up there long before. In April 1923 the fifth Earl of Carnarvon, who had stood at the opening of Tutankhamun's tomb and then died in Cairo, asked to be buried there in a mound of earth, with trees and stones, and not to have more than fifty pounds spent. He was laid in a shaft in the corner of the fort. We know what the grave was for, because he wrote it down. Nobody that day was keeping the faith of the people who dug the ditch. They were taking a high old hill and giving it a meaning of their own.

Twelve centuries, or seventeen, or twenty-two, is long enough for a place to stay standing and lose its name. It does not show that anyone could say who lay inside it. Stonehenge, which might have been the exception, is not much stronger. The Avenue, dug across the change of people, does carry the solstice line out to the river, and that is the best case for a plan remembered. But the later pits outside the sarsens are irregular, and nobody agrees what they were for. What is plain is a long habit of adding a mark: axe-heads cut in the stones, then names, one said to be Wren's, and cremated ashes still placed there, unofficially, in our own time. A claim, repeated. Not a plan obeyed. Shelley's man could read every word that had been cut. The sands were level all the same.

The genomes settle only the blood. It largely changed. A memory could still have been carried across that break: strangers can be taught, and children can forget. Nothing in these graves shows the teaching. The nearest we can come to watching a handing-on is watching one being made. At Stonehenge now, the druids keep a faith they have given the place, one the builders could not have handed them. The handing-on had already stopped, more than once, before anyone in the eighteenth century thought to begin it again. That is not a tradition out of the Neolithic. It is the traveller, returned, finding a family for the ruin. Carnarvon may have his mound. The druids may have their dawn. Neither are keeping an older faith. Both are giving a high old place a meaning of their own.

Vuković, N. et al. (2026). Diachronic reuse of Neolithic burial monuments by Bronze Age newcomers in Southwestern Britain. Scientific Reports 16:26819. 

Carnarvon’s instruction is the codicil to his will, April 1923. 

Shelley, P. B. (1818). Ozymandias.

Woodhenge: the line and the rings

Abstract. The claimed solstitial alignment of Woodhenge is not supported by the layout of its posts. It rests on a line drawn on Cunnington's 1929 plan at the midsummer sunrise bearing (49.4° true, the first gleam in 2500 BC). When the 156 marker posts are fitted ring by ring, every long axis lies north of that bearing. The outer rings A and B are 10–12° north of it, and their 95% ranges exclude the sunrise. The inner rings C–F are 4–8° north. They are too loosely defined to rule the sunrise out, but they do not demonstrate it. Along Cunnington's line from the centre, the view passes through ordinary gaps between posts, and the gaps themselves are centred a few degrees further north.

The June post on Woodhenge accepted the textbook position: the long axis of the timber rings points, broadly, at midsummer sunrise. That position rests on one line, the dashed axis on Maud Cunnington's 1929 plan, labelled "line of midsummer sunrise, elevation of horizon 30′". The new Woodhenge 3D model allows that line to be tested against the post positions themselves. The result is that the line meets the sunrise, but the rings do not follow the line.

The model and its checks

The model places the 156 ring posts (A 60, B 32, C 16, D 18, E 18, F 12) on the concrete markers set out by the Cunningtons, in Ordnance Survey coordinates, on lidar-derived terrain. The twelve supernumerary holes are not included. Two independent plans were used to check the geometry:

• Cunnington's 1929 plan, with its postholes detected automatically and matched to the model by a scale-and-rotation fit: median residual 0.24 m (90% within 0.48 m), rotation −0.1°, no measurable stretch.
• The 2008 GPS survey of the markers by the Jenks brothers: median residual 0.06 m, rotation 0.0°. Three ring-A markers in the east-south-east are missing from that sheet but present on Cunnington's plan.

The centre of the post pattern lies within 1 m of the published position of the monument. The markers are an interpretation of the holes rather than the holes themselves, and they do not precisely preserve the excavated positions (The Past, 2025), but the fit to Cunnington's own plan shows that any such error is well below a metre.

The sun

Sunrise and sunset are computed with the astronomy-engine library (apparent positions, standard refraction, solar semi-diameter 0.27°) against a skyline measured from the lidar terrain at an eye height of 1.6 m above the centre. In the solstice direction that skyline stands at 0.45–0.51°, in good agreement with Cunnington's 30′. For 2500 BC the most northerly midsummer sunrise falls at the following true azimuths:

• first gleam: 49.4°
• half disc: 49.8°
• full disc on the horizon: 50.2°

The modern equivalent (first gleam) is 50.1°. Midwinter sunset in 2500 BC falls at 229.7–230.6°, over a skyline of 0.28°. On this terrain the south-western horizon is lower than the north-eastern one; any obstruction of the midwinter sunset would have to come from something not in a bare-earth model, such as vegetation.

Cunnington's line

Registered to the markers, Cunnington's dashed line lies at 49.4° true and passes within 0.3 m of the centre of the post pattern. It therefore points at the first gleam of the 2500 BC midsummer sunrise to within a tenth of a degree. On the plan the line is marked 50¾° from her north arrow. When the plan is registered, that arrow sits about 1.3° west of true north, which accounts for the difference between the label and the registered bearing.

Figure 1. Cunnington's 1929 plan with the model's marker posts (blue circles) superimposed. Her dashed line runs south-west to north-east at 49.4° true. The orange and green lines are the long axes fitted to rings A–B and C–F. Plan: Cunnington 1929.

The line is drawn at a sunrise bearing through the centre. Nothing on the plan shows it being derived from the posts, and the question is whether the posts agree with it.

Where the rings point

The long axis of each ring was found by fitting an ellipse to its post positions (least-squares conic fit). Uncertainty was estimated by bootstrap: 3,000 resamples of each ring's posts, each post also displaced by a random error of 0.3 m, the fit repeated each time. As a check, the axis of best mirror symmetry of each ring was found independently. It agrees with the ellipse axis to within 3.5° for rings A–E. For ring F the fit is unstable.

Ring	Posts	Size (m)	Long axis	95% range	Short of 49.4°
A	60	44.8 × 40.7	39.7°	35.3–44.1°	9.7°
B	32	39.0 × 34.6	37.5°	32.0–43.2°	11.9°
C	16	29.9 × 25.3	41.0°	32.7–49.6°	8.4°
D	18	23.1 × 19.2	44.4°	34.0–53.3°	5.0°
E	18	18.1 × 14.0	45.2°	35.7–54.6°	4.2°
F	12	11.8 × 8.6	42.7°	26.6–59.7°	6.7°

Azimuths are true (OSGB grid bearing + 0.17°).

Figure 2. The fitted long axis of each ring, with its 95% bootstrap range, against the 2500 BC midsummer sunrise (shaded) and Cunnington's line (dashed).

Every best estimate lies north of the sunrise. None of the rings can point at any sunrise, since 49.4° is as far north as the sun ever rises here. The rings fall into two groups:

• Rings A and B lie about 10–12° north of the sunrise, and their 95% ranges exclude it.
• Rings C–F lie 4–8° north. Their ranges include the sunrise, or in the case of C only just reach it, because rings of 12–18 posts this close to circular do not fix an axis well. If only positional error is allowed for, without resampling the posts, the range for C (35.9–46.0°) also excludes the sunrise, while D (38.6–50.3°) and E (39.4–50.8°) still just include it.

This division matches the suggestion by Chadburn (2010) and Chadburn and Ruggles (2017) that only rings C–F follow the astronomical axis. The fits support it, and add that rings A and B are measurably off it. In Ruggles and Chadburn's grades of precision, C–F sit at the "broadly solstitial" level of about 5°. A–B fall outside it.

The sightline

The Cunningtons watched the midsummer sunrise from the site in 1927 and believed that a gap in the posts could have been used to observe it (The Past, 2025). Along Cunnington's line from the centre, the nearest post centres are as follows:

Ring	Nearest post, NE (m)	Gap centre, NE	Nearest post, SW (m)	Gap centre, SW
F	0.94	46.9°	0.18	238.5°
E	0.30	42.6°	1.07	227.9°
D	1.16	46.5°	0.18	220.8°
C	1.79	45.4°	1.31	223.6°
B	1.04	45.9°	0.37	223.8°
A	0.43	47.4°	0.42	231.0°

Distances are from the post centre to the line. The gap centre is the bearing of the midpoint of the gap the line passes through.

At every ring the line crosses an ordinary inter-post gap. Only ring B's gap is wider than its normal spacing (13.0° against 10.9°), and no corridor is left open along the line. Towards the north-east, the view clears the posts as long as the E posts were less than about 0.6 m across and the A posts less than about 0.85 m. The A posts are estimated at 0.3 m (Marshall et al. 2024). The diameters of the D–F posts are not known. Towards the south-west the line passes 0.18 m from a D post and from an F post, which would block it unless those posts were under about 0.35 m across. The gaps themselves are centred on 42.6–47.4° in the north-east, averaging about 46°, and 220.8–238.5° in the south-west. The open corridor through the rings therefore runs a few degrees north of Cunnington's line, not along it.

Figure 3. The 3D model at first gleam, midsummer 2500 BC, in plan view. The sun ray (yellow) runs along Cunnington's line (white). The fitted C–F axis (green) and A–B axis (orange) diverge from it. Posts are drawn at a uniform 0.64 m diameter.

What this changes

The solstitial axis at Woodhenge is a property of Cunnington's line, not of the timber rings. The line was drawn at the sunrise bearing through the centre of the rings, and the alignment as usually stated derives from it. Measured against the posts:

• rings A and B are oriented about 10–12° north of the 2500 BC midsummer sunrise, and their 95% ranges exclude it;
• rings C–F are oriented 4–8° north of it, which is consistent with a broad solstitial intent but does not establish one;
• the clear sightline along the line depends on post diameters that are known only for rings A–C, and the free corridor through the rings is centred a few degrees further north.

Because the axes lie north of any possible sunrise, they cannot be solar on any date. Lunar and stellar targets are available. At the major standstill of about 2498 BC, the most northerly moonrise (upper limb, over the same skyline) falls at 39.7° and the most southerly moonset at 218.0°. These coincide with the ring A axis (39.7°) and the A–B mean (38.6°/218.6°). Capella in 2600 BC, first visible 1–2° above the horizon, rises at about 43–45°, on the C–F axis (43.3°). Neither coincidence carries much weight. Solar and lunar extremes together offer about a dozen target directions, and the rising and setting points of the first-magnitude stars fall within 3° of roughly a third of all azimuths. The ring axes span 37.5–45.2°, each with a 95% range of 9° or more, so choosing a target ring by ring enlarges the chance further. Nothing independent points to the moon or to Capella at Woodhenge, and no lunar claim for the rings has been published. The coincidences are recorded here so that "north of the sun" is not read as "aligned on something else".

The June post concluded that the long axis of the rings "does point, broadly, the right way". That holds only for the inner rings, and only at the broad end of the precision scale. It does not hold for rings A and B.

Limits

All of the geometry uses marker positions checked against Cunnington's drawn plan, which is itself her record of the holes. An error common to both would not be detected. An ellipse is one model of the ring shape. Thom's egg-shaped constructions define the axis differently and would give different figures. The bootstrap treats posts as interchangeable, which is crude for rings of 12–18 posts. The results would be most improved by the D–F post diameters and an independent survey of the excavated holes.

Sources

• Chadburn, A. 2010. "Case study 2.1: Stonehenge World Heritage Site, United Kingdom." In C. Ruggles and M. Cotte (eds), Heritage Sites of Astronomy and Archaeoastronomy in the Context of the UNESCO World Heritage Convention. Paris: ICOMOS/IAU, 36–40.
• Chadburn, A. and C. L. N. Ruggles. 2017. "Stonehenge World Heritage Property, United Kingdom." In C. L. N. Ruggles (ed.), Heritage Sites of Astronomy and Archaeoastronomy in the Context of the UNESCO World Heritage Convention: Thematic Study no. 2. Paris: ICOMOS, 41–62.
• Cunnington, M. E. 1929. Woodhenge: A Description of the Site as Revealed by Excavations. Devizes.
• Marshall, P., A. Chadburn, I. Hajdas, M. Dee and J. Pollard. 2024. Woodhenge, Durrington, Wiltshire: Radiocarbon Dating and Chronological Modelling. Historic England Research Report Series 94/2024.
• Ruggles, C. L. N. 2006. "Interpreting Solstitial Alignments in Late Neolithic Wessex." Archaeoastronomy 20: 1–27.
• Ruggles, C. L. N. and A. Chadburn. 2024. Stonehenge: Sighting the Sun. Liverpool University Press / Historic England.
• The Past. 2025. "100 years of Woodhenge: tracing an archaeological icon, from discovery to new dating evidence."
• Jenks brothers. 2008. GPS survey of the Woodhenge marker posts (unpublished plan).
• Cross, D. Astronomy Engine (software library).
• Model and data: github.com/TimDaw37/stonehenge-block-3d.