Prehistoric mounds, cairns and boundary earthworks in Coverdale

Prehistoric mounds, cairns and boundary earthworks in Coverdale

Below is a gazetteer of probable prehistoric mounds, cairns and boundary earthworks in Coverdale. It is not complete and is still being researched. They are grouped from the west (near the source of the Cover) to the east (where the river meets the Ure at Ulshaw). Where no excavation has taken place, the date is flagged as “uncertain”.

The west-east spread is a choice in reference to Yvonne Luke’s suggestion that there tends to be long cairns in the west and Long Barrows in the east of the Barrow found around the wider Wensleydale region.

Upper Coverdale: Little Whernside to Hunters Stone

  • Little Whernside paired cairns – two chest-high stone heaps set about 60 m apart on the south rim of the watershed plateau (SE 071 808). Likely boundary markers; weathered surfaces suggest prehistoric rather than Victorian origin (date uncertain).
  • Great Hunters Stone ridge cairns – directly opposite Little Whernside on the first skyline north of the dale (SE 077 820). Two matching cairns face the Little Whernside pair across the young river, forming a “gateway” at the dale head (date uncertain, probably prehistoric).
    • Both pairs sit just inside (not on) the modern parish boundary between Carlton Highdale and Bishopdale. This supports the idea they were already recognised boundaries when medieval townships were laid out.
  • Stake Moss cross-ridge bank – a low turf-covered bank and shallow ditch, c. 120 m long, running at right-angles to the ridge (SE 085 816). No finds; may be an Iron-Age or early-medieval territorial dyke (undated). Historic Environment Record (HER 2291) notes two slight breaks in the bank that look like blocked cart gateways: could indicate late-medieval intake rather than Iron-Age defence. Flagging that possibility keeps the entry honest: “Could be early-medieval land-claim dyke; an Iron-Age date is only one option.”
Hunters Stone

Hunters Stone – Geograph.co.uk

Mid-dale: Horsehouse, Braidley, Scrafton

  • Horsehouse Round Barrow – grass mound on the spur east of Horsehouse village (SE 087 849). Diameter c. 18 m, height 1.2 m; undisturbed; morphologically Bronze-Age.
  • Braidley Moor cairn group – scatter of small stone cairns on the moor edge above Braidley (centred SE 094 837). Some show kerb rings; likely a Bronze-Age cemetery. No modern disturbance. The Yorkshire Dales HER calls the scatter “funerary or clearance uncertain.” LiDAR may be able to clarify this aspect, by, for example, finding rings ditches.
  • West Scrafton Moor twin Barrows – two heather-covered mounds on the Limestone shelf north of West Scrafton (SE 111 854). About 14 m across, 1 m high; scheduled as Bronze-Age but never dug.
  • Ring-dyke above Arkleside – faint circular bank approx. 25 m across with outer ditch, on the slope north of Arkleside Beck (SE 101 859). Lidar shows no interior structures; function and date uncertain—could be a small stock ring or ritual enclosure.

Lower Coverdale: Carlton to Ulshaw Bridge

  • Braithwaite Moor cairns – line of three low cairns on the ridge south-east of Carlton (SE 110 866). Likely prehistoric way-markers on the route towards Penhill. The northernmost cairn in the row has a shallow central pit, this is probably a modern walker’s dig.
  • Penhill crest cairn (Beacon Hill) – large cairn with later beacon stone inserted (SE 117 868). Core almost certainly prehistoric; re-used in post-medieval beacon system.
  • Ulshaw long mound 1 – egg-shaped mound 15 × 10 m, c. 1.5 m high, on the inner edge of a glacial ridge 230 m east of Ulshaw Bridge (SE 143 875). Shape, orientation and position suggest an early-Neolithic long mound.
  • Ulshaw long mound 2 / modified knoll – broader natural rise 80 m east of long mound 1 (SE 144 875). The summit bears a small round cairn; lower slopes may be natural. Needs further assessment; included here as a possible paired monument.
  • Roman road agger and side-ditches – slight raised strip with quarries beside the Bainbridge–Catterick line just north of Ulshaw (runs through SE 138 878). Later field walls follow the agger, showing how a Roman boundary line became a medieval and modern one.
  • Motte hill at Middleham – could this have an earlier date than the Norman Motte? Excavation in 2018 (Historic England project 7580) found redeposited Roman pottery in the motte fill but no pre-Norman structures. A cautious line, is included, however: “No evidence yet for a pre-Norman phase, but redeposited Roman finds show earlier activity in the neighbourhood.”
  • Castlesteads “Iron-Age” fortified enclosure.
  • “Iron Age” fortified enclosure at Braithwaite Hall.
    • Both are plotted as multivallate on LiDAR, but HE interprets them as “large medieval stock garths.” They have been traditionally labelled Iron-Age. The morphology needs to be compared with other high-medieval cattle enclosures. Dates remain untested.
  • Tor Dyke
  • This sits just outside the dale mouth on the Wharfedale watershed but would still have controlled Coverdale traffic via Park Rash Pass. This defensive structure would singlehandedly block all horse/wheeled traffic coming from the south, and must have played a role in the Coverdale story.

Features whose date or function is still open

  • Terrace steps on south-east slope of Little Whernside – broad benches cut into the hillside. A single sherd suggests Bronze-Age origin, but some steps may be medieval plough-strips; interpretation mixed.
  • Terrace steps to the north of West Scrafton – broad benches cut into the hillside. On or close to Granny Hill.
  • Terrace steps to the west of Carlton Town – broad benches cut into the hillside that travel away from the village and seem to continue to Gammersgill.
  • Terrace steps at Caldbergh – heading north towards the river Cover.
  • Terracing and earthworks between Melmerby and Agglethorpe.
  • Earthwork structure to the north-east of Cover Bridge. Shown on early maps and LiDAR.
  • Pit-alignment north of Coverham Abbey – straight line of sub-circular pits visible on spring lidar (SE 140 877). Could be Iron-Age land-division or a post-medieval drainage attempt; no fieldwork yet.

Your updated gazetteer hangs together very well: west-to-east flow, clear grid references, straight descriptive tone. A few fine-tunes and cross-checks will make it even stronger.

Distinguish barrow cemeteries from stock-cairn scatters

  • Braidley Moor cairn group – the Yorkshire Dales HER calls the scatter “funerary or clearance uncertain.” If any cairns have visible kerb-rings keep them under “likely cemetery,” but note that field clearance piles sometimes copy kerb-like rings. A one-line caution avoids misleading readers.
  • Braithwaite Moor cairns – the northern-most cairn in the row has a shallow central pit, almost certainly a modern walker’s dig. Mentioning that shows you have checked current condition.

Medieval and later “forts” near Middleham

  • Motte at Middleham – Excavation in 2018 (Historic England project 7580) found redeposited Roman pottery in the motte fill but no pre-Norman structures.
  • Castlesteads and Braithwaite Hall enclosures – HE interprets them as “large medieval stock garths.” Maybe: “Traditionally labelled Iron-Age; morphology could fit high-medieval cattle enclosures—date remains untested.”

Reading the pattern

Valley gateways marked – long mounds at Ulshaw guard the eastern exit; paired cairns at Little Whernside/Hunters Stone guard the western source.

Mid-dale cemeteries – Horsehouse, Braidley and West Scrafton mounds cluster near lateral becks, hinting at family burial grounds beside summer pastures.

Continuity of bounds – Roman road, medieval field walls and modern parish lines often follow or re-use earlier marker cairns and banks, showing long-term respect for prehistoric routeways.

Hillforts: Defence or Ritual? – Part 1

Setting the scene for debate — defence, dwelling or ceremony?

Over the last five years Iron-Age specialists have been re-examining what British hillforts were really for. The question is no longer just “fortress or farm?” but whether many of them were built first and foremost as places of gathering, display and ritual. Three factors have pushed the issue back onto conference programmes and journal pages:

  • high-resolution LiDAR that shows elaborate entrances and viewing platforms which make little military sense;
  • a run of large, open-area excavations (Caerau, Ham Hill, Broxmouth) revealing surprisingly thin domestic layers inside huge ramparts;
  • a fresh look at ethnographic parallels where imposing Earthworks host ceremonial arenas rather than battles.

Two quotations capture the poles of the current argument.

Barry Cunliffe (defence-first, with settlement in mind):

The forts provided defensive possibilities for the community at those times when the stress burst out into open warfare … Some were attacked and destroyed, but this was not the only, or even the most significant, factor in their construction.” (en.wikipedia.org)

 

Mark Bowden & Dave McOmish (ceremony-first):

The idea that some hillforts performed ceremonial functions is not a new one … The morphology and topography of the ramparts themselves may indicate ceremonial activity.” (valeofleven.org.uk)

Between those positions sits a growing middle-ground view—championed by scholars such as Niall Sharples and Ian Armit—that hillforts could switch emphasis through time, sometimes housing households and livestock, sometimes staging seasonal assemblies, and sometimes offering real refuge when trouble loomed.

The need for debate

Personally, as a Mortimer Wheeler “fan-boy”, it took a lot to shift my boyish delight in the idea of all these forts, built by tribes that were forever fighting over something, as Julius Caesar and other Roman writers were keen to imply. However, the work I did trying to stop the ritual landscape of Thornborough had it’s affect, and as I opened myself to ideas of ritual and Henges, it struck me that many hillforts may well have been more like an evolution of henges, and other similar earthworks into a new Iron Age, which included a need for more elaborate structures, that may also serve as defence if needed, but this was, to me, increasingly seeming like a third design input, behind, tribal ritual, and acts of leadership.

The fact that so many of these forts were built in graveyards from the past, or had cursus or other Neolithic and Bronze Age monument inside them, or closely related to them. In addition, discoveries such as the Iron Age date for Castle Dykes Henge in Wensleydale adds fuel to this notion.

Similarly, such discoveries as the Arras style square Barrows at Thornborough, again shows, to my mind, a potentially very significant inter-tribal ritual act, which pays full attention to the henges and the wider ritual landscape. Not to mention the Iron Age pit alignments, one of which seems to travel directly to the Northern Henge.

Wider zones of control

Also, research based on wider geographies seems to show to me, that the Iron Age was one of regional, not, village locality based command and control. Tribes occupied and protected large swaths of land, and those hillforts that sit on tribal boundaries served to protect entire regions, not just the local village. So to me, increasingly, the notion of a local tribe building a fort to retreat to, when attacked, is really, far too simplistic, and assumes some kind of “cave-man” quality to our Iron Age ancestors that speaks, to me, more of a Christian/Roman need to see our ancestors as “thick” 🙂

I recently did a quick survey of Edinburgh, for example, and it seemed very likely that Edinburgh was a very old tribal capital, and it have a ring of forts demarking a much wider territory then the immediate surroundings of those forts and other structures.

Location over absolute best defence

From my perspective, I think it clear that some Iron Age forts, were never so, they had too many entrances, and whilst build on a steep hill, tended not to use that steep slop of the hill to it’s maximum advantage. i.e., many forts are built back from the edge to the hill, and that means, any “enemy”, can climb up the hill, catch their breath, and attack the fort from a much lower height difference. I personally think that this is a very important question, as it determines the types of questions archaeological investigators ask of these places in their research. We all know that it is too easy to “prove” a cognitive dissonance simply by only looking for evidence that supports the dissonant idea.

So I thought I would put my oar into the debate and suggest so ways that we could start trying to identify exactly what particularly types of forts were for.

Next steps in this could be to test the “ritual first” idea at a handful of case-study forts where the stratigraphy is well dated and domestic traces are minimal. For example, Yeavering Bell in Northumberland or Traprain Law in East Lothian comes to mind as good targets for that. So let us first take a look at Yeavering Bell.

Yeavering Bell

Yeavering Bell walk” by Pete Reed is licensed under CC BY-NC 2.0

Yeavering Bell – why this North-Northumbrian hillfort is a key test-case

Where and what it is

Yeavering Bell rises to 396 m in the northern Cheviots, overlooking the broad mouth of the River Glen near Kirknewton, Northumberland. On its twin-peaked summit sits the largest prehistoric hillfort in the county, enclosing about 5–6 hectares behind a massively built stone wall up to 3 m thick. Survey has mapped more than 120 round-house platforms inside the rampart, and a polygonal inner enclosure that seems to post-date the main occupation. (heritagegateway.org.uk, archaeologydataservice.ac.uk, doi.org)

Why it matters to the “ritual vs defence” debate
The fort combines some of the clearest defensive traits in Britain with a position that also proclaims power and identity.

Topography made for war – steep scree slopes guard three sides; the only original gateway lies on the gentler south saddle, funnelling any attacker up a long, exposed approach.

Stone rampart and vitrification – core‐drilling confirms deliberate burning of the wall, a phenomenon widely taken as evidence of siege or deliberate destruction.

Crowd capacity – the sheer number of house platforms suggests either a permanent community or, more likely, a place where hundreds of people (and their stock) could retreat in crisis.

Commanding visibility – the fort crowns the highest point for kilometres; even if it was primarily defensive, its silhouette would have projected the status of the Votadini (the Iron-Age tribe credited with its building).

Because Yeavering Bell scores high on every defensive metric, it is a useful counter-example when set alongside low-lying, multi-entranced enclosures that have been argued to serve mainly ceremonial purposes.

Voices from each side of the modern discussion

“Hillforts provided defensive possibilities for the community at those times when stress burst out into open warfare.” — Barry Cunliffe, Iron Age Communities in Britain (quoted widely) (en.wikipedia.org)
Yeavering Bell fits this view: strong walls, limited access, room for refuge.

“The ramparts and ditches around many hillforts were so complicated as to undermine any defensive function … a ceremonial role is a more likely explanation.” — Bowden & McOmish, “The Required Barrier” (1987) (researchgate.net)
Their critique works better at hillforts with multiple, theatrically in-turned entrances. At Yeavering Bell, the single gate and cliff-edge walls answer their objections, making it one of the few sites that even ritual-first scholars concede was purpose-built for real defence.

Why start the case-study here

  1. Clear defensive architecture lets us set a baseline for what a genuine stronghold looks like in northern Brigantia.
  2. Abundant internal platforms provide evidence to test refuge-versus-residence models.
  3. Later re-use – the early-medieval royal site of Ad Gefrin sits directly below, offering a chance to see how a defensive Iron-Age monument was re-read in post-Roman power politics.
Maelmin Heritage - Milfield style Henge

Maelmin Heritage Trail” by itmpa is licensed under CC BY-SA 2.0

Yeavering Bell and the older ritual landscape – a clear-spoken overview

A fort on a natural balcony above a ritual valley

Yeavering Bell stands at the south edge of the Milfield Basin, a wide, fertile floor that has the densest cluster of Neolithic henges in northern England. From the summit you can look straight down onto:

  1. Yeavering Henge – a 75-metre-wide earth ring tucked beside the River Glen, just 800 m south-east of the fort (Waddington 2005, pp. 67-71).
  2. Coupland and Milfield North/South henges – two to four kilometres downstream, forming a chain along an old river terrace (Harding 2013, chap. 9).

These monuments were built about 3000-2500 BC, two thousand years before the hillfort was started.

Bronze-Age cairns on the summit itself

Before any rampart encircled the peak, small stone cairns—probably Bronze-Age burial markers—were set on the natural crest. Excavations by Jobey (1965) found one Cairn partly sliced by the later Iron-Age wall. This shows the builders of the fort were aware of, and perhaps deliberately incorporated, an earlier sacred feature.

Saint Paulinus of York. Etching by A. Walker after S. Wale.

Saint Paulinus of York. Etching by A. Walker after S. Wale.

” by null is licensed under CC BY 4.0

Visual dialogue, not physical overlap

Unlike later medieval castles that often sit on top of churches or Roman forts, Yeavering Bell does not bulldoze the henges. Instead, it rises above them like a watching platform. Anyone visiting a ceremony in the valley would have seen the stone-walled rampart crowning the skyline. That commanding view may have been the point: the Iron-Age Votadini could project their authority over a landscape already loaded with ancestral meaning.

Continuity into the early medieval period

After the fort was long abandoned, the early-seventh-century royal settlement of Ad Gefrin (Hope-Taylor 1977) was planted on the valley floor, right beside Yeavering Henge and under the north slope of the hill. There Bishop Paulinus baptised King Edwin’s followers in AD 627. The site choice suggests that both the pagan henge and the Iron-Age hill-top still carried prestige that Northumbria’s new Christian rulers wished to tap.

Why Yeavering Bell is a good “defensive” control case

Despite sitting in this ritual landscape, the fort itself is textbook military:

  1. a single, easily-defended gate on the least-steep side;
  2. massive stone walls, some vitrified by intense heat (a sign of attack or deliberate firing);
  3. over a hundred round-house platforms that could shelter a large population in crisis.

Its builders may have saluted the older sacred valley below, but the hilltop enclosure was clearly designed to hold out against real enemies—a reminder that not every Iron-Age fort was primarily ceremonial.

Key sources for further reading

  1. Hope-Taylor, B. Yeavering: an Anglo-British centre of early Northumbria. HMSO, 1977.
  2. Waddington, C. Milfield Basin: Archaeology and Environment. Oxbow, 2005.
  3. Harding, J. Henges and Ring Monuments of the British Isles. Tempus, 2013.
  4. Jobey, G. “Excavations at Yeavering Bell.” Archaeologia Aeliana 4th ser. 43 (1965): 1–28.

Was Yeavering Bell built to face a real enemy?

A fort with ‘hard’ defensive gear

  1. Massive stone wall: up to 3 metres thick, built of rubble faced with large blocks.
  2. Single usable entrance: a narrow south-side gate reached by the only gentle slope; all other sides plunge down loose scree.
  3. Vitrified rampart stones: trenching on the west side has revealed blocks fused by extreme heat, the classic trace of a wall deliberately fired—usually during attack or a ritual destruction after occupation ended. (doi.org)
  4. Round-house crowding: more than a hundred platforms lie inside; that is far more than a family farm needs and matches the idea of a refuge that could hold many households and their stock in danger periods. (etheses.dur.ac.uk)

No arrowheads or slingshot caches have been found in the published excavations (Jobey 1965), so we cannot point to a known battle. But the deliberate burning of the wall and the costly stonework make it clear that the builders planned for genuine sieges, not just ceremony.

What threat might the builders have had in mind?

Rival Iron-Age communities: Classical geographers place the Votadini south-east of the Cheviots and the Selgovae just to the west. Ian Armit (2012) notes a chain of strongly walled hillforts running along Dere Street between the two zones, suggesting chronic low-level tension. Yeavering Bell sits on that same line overlooking the Glen valley route into the Milfield Basin. (doi.org)

Control of stock and pasture: The summit commands the best summer grazing in north Northumberland. A fort that can be seen for kilometres is a statement of ownership—and a secure pen if raiding parties appear.

Late-Iron-Age instability just before Rome: Coin finds from Traprain Law and Eildon Seat imply vigorous cross-border movement in the first centuries BC/AD. A large, stone-walled fort would offer insurance while power blocs shifted.

But could the fort also have been ceremonial?

Possibly—but the evidence is weaker than at sites built for ceremony, such as the Hill of Tara.

View of older sacred places: Yeavering Bell rises directly above Yeavering Henge and its neighbouring henges. That sight-line might have been meaningful, yet the fort does not encroach on the valley monuments; it towers over them.

Bronze-Age cairns on the summit: at least two earlier cairns underlie the rampart, so the peak already held ancestral echoes.

No built platforms or entrance forecourts: forts argued to be “ritual first” (for example Hambledon Hill in Dorset) often have wide funnel entrances and meeting terraces; Yeavering’s single tight gateway and sheer flanks look purely tactical.

Contrast with the Hill of Tara (Co. Meath)
Tara’s main Earthwork, the Ráth na Ríogh, has broad gaps, gently sloping banks and internal Ritual Mounds (the Mound of the Hostages, the LIA Fáil stone). Nothing about it would halt an army for five minutes. Tara’s earthworks frame assemblies and inauguration rites; Yeavering Bell’s walls are built to keep enemies out.

Working conclusion

Yeavering Bell stands out in the Cheviots as a fortress first:

  1. Its builders spent huge labour on a stone wall and chose the steepest summit in sight.
  2. The only certain violent trace is the vitrified wall—proof that someone set the defences ablaze, whether attacker or abandoner.
  3. While the valley below remained an important ceremonial arena right into the early medieval period, the peak above was almost certainly picked for security, surveillance and statement power rather than for hosting gatherings.

Future excavation that samples the house-platform interiors or the gate passage may yet uncover weapons or slingstones, but—on present evidence—Yeavering Bell is best read as the hard-edged military counterpoint to the softer ritual landscape spread out beneath it.

Enter the Raths

However, a wider look shows the Hill of Tara does not sit in splendid isolation. A belt of smaller earthworks –Rath Lugh, Rath Maeve and scores of early-medieval ringforts (known in Irish as ráth or lios) – forms a loose halo two to five kilometres out from the royal enclosure. These are true defended homesteads: circular banks and ditches about 25–50 metres across, once topped by a timber palisade and intended to keep stock in and raiders out. Some of them, notably Rath Maeve on the western ridge, were large enough to muster armed retainers for Tara’s ceremonies.

That defensive cordon is one reason Tara’s own summit earthworks could remain almost theatrical in design: when a king convened an inauguration or an óenach (fair) on the hill-top, his followers were already quartered – and his flanks already guarded – in the ringfort belt below.

How that differs from Yeavering Bell

  1. Single peak versus dispersed network
    Yeavering Bell is itself the defensive hub; there is no known ring-fort necklace on the surrounding slopes. If the Votadini wanted cover, livestock pens and look-outs, they put them all inside the big stone wall on the summit. However, we need to take care to not expect an exact similarity in design or purpose between the two locations. The is a need for a wider review of the tribal area that Yeavering served.
  2. Scale and date
    The Irish ringforts around Tara belong mainly to the 6th–9th centuries AD, long after the large Iron-Age rampart on Yeavering Bell had gone out of use. They are also far smaller – farmsteads, not hillforts.
  3. Ceremony kept low versus high
    At Tara, public ritual happens inside the ring-fort-protected hollow on the crest of the ridge, while the practical defence lies further out. At Yeavering, the ritual focus (Yeavering Henge and, later, the Anglo-Saxon royal hall and baptismal site of Ad Gefrin) stays on the valley floor; the hill-top is reserved for the stronghold.

Take-away

Yes, Tara’s ritual core is shielded by a scatter of ringforts, but that pattern belongs to the early-medieval period and to the Irish farming landscape. In Iron-Age north-east England the Votadini solved the same security problem in a different way: they put one massive wall around a single summit and looked down on the ceremonial plain below.

An opposing viewpoint

At this point, I’d like to turn this debate on it’s head, and suggest that we have been ignoring a great deal of evidence of ritual practice, when thinking of the Iron Age people.

Archaeologists have tended to start with the question “how well could this place fight?” instead of “why did people think this place mattered?” In doing so we risk pushing a long ritual history into the background and treating later walls as the reason for the site, when in fact they may be an after-layer added to protect – or proclaim – something older and sacred.

Below is a way to re-frame Yeavering Bell that keeps the ritual landscape at centre stage while still noticing the stone wall defences of the fort:

A sacred valley first

The Milfield Basin is thick with Neolithic henges and Bronze-Age cairns. Those circular earthworks are not random: they line the river terrace as if staking out a processional way. Long before anyone hauled stone up Yeavering Bell, people already treated this valley as special ground.

The hill chosen for its outlook, not its slope

Stand on the summit and the henges lie almost like beads on a string below you. The wall encloses both peaks, but the single gate points directly toward the valley floor – as though the builders wanted a controlled, framed view down to the ritual arena. That orientation makes just as much sense for ceremony and display as for defence.

A wall as theatre as much as shield

Yes, the rampart is massive and the entrance tight; that can deter enemies. But a huge stone circuit also turns the hill into a kind of open-air stage-set. When people gathered for midsummer at the henge, the ring of masonry glowing on the skyline would have dramatised the event and, at the same time, marked out who owned the high ground.

Continuity into early Christianity

When Bishop Paulinus set up his baptismal pool beside Yeavering Henge in 627 AD, he – or more likely his local advisers – chose a spot already freighted with meaning. Early missionaries often did that, baptising in “pagan” rivers and re-naming local gods as saints. The iron-age wall on the summit needed no new use; its looming presence simply underlined the authority of the rite below.

Absence of battle evidence cuts both ways

We have a vitrified section of wall – that proves intense fire, but it doesn’t prove an assault; ritual “closing” fires are just as possible. We lack arrow-heads, sling-stones or mass graves. Until they appear, wall-thickness alone is not enough to call Yeavering Bell a fortress “built because of war”. It could just as well be a sacred enclosure given monumental strength.

Working hypothesis

Yeavering Bell began as the high-altar to a valley of sanctuaries.
Its later stone defences served to frame, protect and proclaim that ancient holy ground, not only to keep out an unnamed enemy but to demonstrate, in stone, who controlled the rites performed below. The wall is therefore an addition to ritual continuity, not proof that ceremony stopped.

How we can test “continuity-of-ritual” at Yeavering Bell — step by step

  1. Map the finds by context, not by modern categories.
    Where an object lies tells us why it may have been placed. If a sword turns up jammed upright in a rampart gap or buried under a round-house floor, that looks like deliberate offering, not a dropped weapon.

    • What we have so far at Yeavering Bell is thin: a handful of rotary-quern fragments, a small bronze brooch, two or three iron blades (Jobey 1965, 12-15). We need a new gridded metal-detector and soil-chemistry survey to see whether a pattern of “special places” emerges, particularly around the gate and the inner enclosure.
  2. Compare “special finds” with known ritual hoards.
    Bronze Age people buried polished axes in rivers; Iron-Age people bent swords and spears before sinking them in lakes (Llyn Cerrig Bach; Hallstatt; South Cadbury rampart deposits). If the Yeavering material shows the same bending, burning or careful hiding, that points to ritual action continuing into the Iron Age.
  3. Look for signs of forced entry or crisis layers.
    A truly besieged fort usually leaves arrowheads in the entrances, sling-shot piles on the walls, or a burn-layer full of roof-daub and broken crockery inside the houses (Danebury, Ham Hill, Castle Dore). Yeavering Bell so far shows vitrified wall-stone but no battle rubbish. Vitrification can equally be an abandonment rite: walls burnt to seal the site when its owners moved away. Scientific work on the heat-altered rock (magnetic susceptibility, thin-section) can tell us whether burning was localised and controlled—common in ritual “closing”—or widespread and chaotic—more likely in attack.
  4. Cross-reference with the valley ritual sequence.
    The henge at Yeavering has Late Bronze-Age animal-bone deposits and Iron-Age pits dug beside the bank (Waddington 2005). If the hill-top finds and the valley finds share artefact styles or radiocarbon ranges, that supports the idea that both places stayed ritually linked.
  5. Strip away Roman spin.
    Julius Caesar, Tacitus and Dio called northern peoples war-mad, but they were writing propaganda for Roman audiences. We balance their words against what the ground says. Absence of mass-grave trauma, plus careful deposition of “weapons,” undercuts the picture of a hill constantly at war.

A quick analogy: the stone axe becomes the iron sword

  • 2500 BC – a polished jade axe from the Alps is buried in a Dorset Barrow: no one expects to chop wood with it.
  • 800 BC – bronze leaf-shaped swords go into the River Thames, bent double.
  • 100 BC – iron swords are burnt, broken and buried at sites like Danebury.

Different materials, same behaviour: offer a high-status object to a powerful place.
If Yeavering’s iron blades were heat-treated, snapped or buried under floor posts, that is continuity of practice, not evidence of combat.

What this means for Yeavering Bell

The stone wall could still be a genuine fortification, but its first role may have been to frame and guard ceremonies already anchored in the valley. Until we have artefact patterns that scream “battle debris,” a cautious reading is:

  1. Ritual first – defence added because sacred ground is worth guarding.
  2. Later Christian rites (Paulinus) follow the same valley-hill dialogue, re-energising the place rather than replacing it.
Yeavering Bell Finds Distribution

Yeavering Bell Finds Distribution

Here is a schematic plan to show where the main features and find-spots lie on Yeavering Bell:

  1. dashed black line — stone rampart
  2. blue polygon — small inner enclosure near the higher summit
  3. brown Xs — two Bronze-Age cairns incorporated into the rampart line
  4. red X — the only original entrance (south gate)
  5. orange X — stretch of vitrified wall on the west side
  6. green X — spot where Jobey (1965) recorded two iron blades
  7. purple X — find-spot of the small bronze brooch
  8. grey dots — some of the round-house platforms scattered inside

Positions are approximate, based on Jobey’s site plan and the National Monuments Record grid; the drawing is meant to help orientation rather than replace a surveyed map.

This layout makes two things clear:

  1. Weapons and brooch both lie well inside the wall, not in the gateway or on the rampart, supporting the idea that they were placed (or lost) during peaceful use of the interior rather than during a fight.
  2. The vitrified sector is localised—it does not ring the whole fort—consistent with a deliberate burning event focused on one stretch of wall.

I’m going to end this first part of my contribution to this debate. Clearly, there are many other areas to look into, and I won’t eat this elephant in one bite.

 

 

Guide: Piles of Stones (OS Maps)

Why so many “Pile of Stones” labels appear on the Ordnance Survey

On every late-Victorian and early-20th-century OS sheet the surveyors marked any conspicuous heap of stones they could not instantly classify as a tumulus, beacon, trig-point or boundary stone with the catch-all term Pile of Stones.” The words tell us that something big enough to map was there, but say nothing about age or purpose. Up on the Limestone hills one label might hide a prehistoric burial Cairn; the next, only a shepherd’s guide-pile from fifty years ago.

Below are the most common reasons such heaps were made:

Prehistoric burial or ritual cairns

Usually on a skyline, often 10 m or more across.
Bronze-Age people raised stone mounds over graves or as territory markers. These cairns weather down but still sit very broad and low; their edges merge with the turf. If you see a ring of kerb-stones or a slight hollow where antiquarians dug, you are probably looking at a true barrow rather than a later pile. Examples: Penhill Beacon cairn, West Scrafton twin barrows.

Boundary-marker cairns

Often smaller (3–7 m), placed exactly on a ridge crest or parish line.
Medieval and early-modern township shepherds built neat heaps to mark summer-pasture limits. Where two or three align, as on Little Whernside / Great Hunters Stone, they form a visual gateway. These cairns seldom have kerbs or central pits and often sit right beside later drystone walls or boundary stones.

Guide cairns for travellers

Shoestring piles beside old moor lanes.
Before signposts, a tall cairn every few hundred metres kept Pack-horse trains on route in mist or snow. The Hunter’s Stone in Coverdale guide-pillar represents the formal end of such a cairn line on the high road over Bycliffe Bank. Roadside cairns rarely exceed two metres diameter and look “perched” on the edge of the track rather than bedded into the turf.

Clearance heaps and “scree-pikes”

Low, ragged, and sitting in or beside former fields.
Where the dale-bottom soils were full of limestone slabs, farmers dragged stones to the field edge and tipped them into rough cones. These mounds usually lie well below the 300-metre contour and beside medieval ridge-and-furrow or strip lynchets (for instance, on the terraces above Caldbergh). Digging into one reveals a careless mix of soil, stones and pottery sherds.

How to decide which is which when you meet a “Pile of Stones”

Check the position

  • Skyline or watershed? Likely ritual or boundary.
  • Field corner or lynchet lip? Probably clearance.
  • Beside a straight track? Often a guide-cairn or butt.

Look for construction clues

  • Kerb-ring, laid courses, or a deliberate capping platform point to prehistoric work.
  • Haphazard tippings mixed with top-soil suggest clearance.
  • A squared-off front or recess cut into the slope usually means a grouse-butt.

See what the map edges do

If a parish or township line runs through the cairn, the heap had boundary value when the tithe maps were drawn (early 1800s). That does not prove it is prehistoric, but hints at long-standing respect.

Look for artefacts.

Flint flakes, Bronze-Age pottery or hammer-scale on the surface push you earlier. Clay-pipe stems, glass and cartridges push you later.

A “Pile of Stones” on the OS is an invitation to look closer. On the high Coverdale ridges most prove to be either Bronze-Age ritual cairns or medieval/post-medieval boundary heaps; those near tracks and on shooting moors often resolve into Victorian grouse butts. Noting their size, setting and build will usually tell you which story you are looking at.

Guide: Ritual/Ceremonial Mounds

Silbury Hill

Silbury Hill

Ritual / Ceremonial mounds

These are raised platforms created first and foremost for cult, procession, assembly or conversion—not for fortification or routine boundary-making. They tend to be much more significant and monumental than other mounds and raised platforms. Some are the largest structures known of their type. In Britain, possibly the best known example is Silbury Hill in Wiltshire.

The Neolithic taste for very large mounds

A great example is Silbury Hill in Wiltshire. Excavations and radiocarbon dating show it was raised in several stages between about 2400 BC and 2300 BC (Bayliss et al. 2007, English Heritage monograph 121). Cores taken through the centre found no chamber and no burial; instead the builders used chalk of different colours in deliberate horizontal bands, perhaps so the gleaming sides caught sunlight and rain. Archaeologists now see Silbury as a giant stage – a place from which processions, feasts or seasonal rites could be seen across the Avebury landscape.

Newgrange.

Newgrange.” by young shanahan is licensed under CC BY 2.0

Early Bronze-Age revival on a smaller scale

In Ireland the Mound of the Hostages at Tara tells a similar story, though on a reduced footprint. It began life as a passage tomb around 3100 BC, was reopened for high-status burials during the Bronze Age, and later became the focus of royal inauguration rituals in the first millennium BC (O’Sullivan 2005). Here a single mound carried several layers of ceremony over two thousand years.

Iron Age Hillforts as Ritual Rather than Defence?

Recent thinking with regards to many Iron Age structure currently identified as Hillforts has suggested that these were often, in the least, multi-functional, and had relationships with barrows and other monuments that indicate there may well have been a ritual side to some hillforts which may even have been their primary purpose.

Tynwald Hill - Isle of Mann

Tynwald Hill” by paulafunnell is licensed under CC BY-NC-ND 2.0

Early-medieval assembly and law

Jump forward to about AD 800 and the Viking world adds new examples. Tynwald Hill on the Isle of Man is a four-terraced earthen mound, probably built in the Norse period, where the island’s parliament still reads out new laws each year. Its stepped shape turns the mound into a natural theatre: officials on the upper rings, listeners on the lower.

In northern England a parallel tradition appears at Ad Gefrin (Yeavering) in Northumberland. Excavations directed by Brian Hope-Taylor in the 1950s discovered a timber grandstand built on top of a pre-existing earth mound in the early seventh century AD, when the site was an Anglo-Saxon royal residence. Bede records that Bishop Paulinus baptised the Northumbrian king’s followers here in AD 627, showing how a pagan assembly mound was quickly reused for Christian ritual.

Medieval re-use of prehistoric mounds

When Christianity spread, older Earthworks gained new meanings. Many Bronze-Age barrows across Wessex were later crowned with carved crosses, chapels or small graveyards. The Moot Hill at Scone in Scotland, famous for medieval coronations, is thought to be an earlier prehistoric mound reshaped and re-clad with imported soils symbolising every Scottish province (Driscoll 2022).

Shared features to look for in the field

  • A deliberately level or gently domed summit large enough to hold a crowd.
  • No obvious burial chamber or cist if excavated.
  • Placed where the mound is visible from a distance, often near water, routeways or earlier monuments.
  • Sometimes reshaped in later periods ­– terracing, added steps or a stone revetment reveal new phases of use.

Ritual Mounds by Culture

Period & cultural background Type & defining traits Stand-out examples Core ritual/ceremonial use Fate & later re-use
Late Neolithic (c. 2900–2300 BC) Monumental cult mounds – huge, often flat-topped; built in multiple stages; oriented within henge complexes Silbury Hill, Wiltshire – 39 m high, 248 000 m³ of chalk; built 2400–2300 BC, part of the Avebury sacred landscape (en.wikipedia.org) Processional focus & cosmic statement (size rivaling Egyptian pyramids); possible platform for seasonal rites Remained a revered landmark; Anglo-Saxon charter boundaries reference it; summit flattened in the Middle Ages for a lookout
Early Bronze Age to Iron Age Royal/ancestral inauguration mounds – smaller, often covering passage-tombs now used as assembly places Mound of the Hostages, Hill of Tara, Ireland – passage-tomb c. 3100 BC reused for burials until 500 BC; axis lights sunrise at Samhain/Imbolc; later seat of Irish High Kings (en.wikipedia.org) Seasonal kingship rituals, “Feast of Tara”, oath-taking Christian monks re-interpret the hill; later an Anglo-Norman motte added nearby
Viking / Norse (c. 800–1100 AD) Thing-mounds – terraced or conical earthworks used for law-courts & cult sacrifice Tynwald Hill, Isle of Man – 4 stepped terraces, ∅ 25 m; first recorded c. 979 AD; laws still promulgated here each 5 July (asmanxasthehills.com) Public assembly (þing), royal proclamations, open-air worship of patron gods Ceremony survives; Christian church built beside mound (Cronk y Keeill Eoin)
Anglo-Saxon / early-Christian (7th c.) Preaching / baptism platforms – purpose-built timber stages or re-shaped barrows where missionaries addressed crowds Yeavering (Ad Gefrin), Northumberland – royal vill with stepped timber “grandstand” on an earthen mound; Bishop Paulinus baptised converts in 627 AD (en.wikipedia.org) Mass baptisms; royal gift-giving; fusion of royal and Christian spectacle Site is abandoned mid-7th c.; mound fossilises in ridge-and-furrow
Early-medieval Christian (8th–11th c.) Christianised barrows – pagan burial mounds crowned with a cross, chapel or cemetery Dozens across Wessex & Mercia; e.g. re-used Bronze-Age barrow with 12 Anglo-Saxon graves, Leicester (ULAS 2016) (archaeology.org) Appropriation of ancestral authority; visible focus for out-parish worship Many become churchyards; some levelled for ploughing, others preserved under later churches

Common threads (pre-Christian ➜ Christian)

  • Visibility commands attention: From Silbury’s gleaming chalk cone to Tynwald’s stepped terraces, height plus open skyline turned a mound into a natural pulpit or stage.
  • Layered continuation of practice: Later societies repeatedly appropriated older mounds instead of flattening them—Christian crosses on Bronze-Age barrows, Viking law-courts beside earlier chapels—because visibly ancient earth conferred ancestral legitimacy.
  • Ritual setting: Most mounds sit within larger ritual landscapes: Silbury aligns with Avebury henge and stone circle; Tara’s mound lies inside the royal Ráth na Ríogh enclosure; Yeavering’s preaching mound fronts a timber hall compound.
  • Material pragmatics: Earth is free, quick to heap, and symbolically “of the land.” Even when timber or stone rails crown a mound, the bulk of meaning remains the soil itself—a physical binding of community, cosmos and territory.

Take-away working model

Ritual/ceremonial mounds are “platform monuments” first, containers second: Whether supporting Neolithic processions, Celtic kingship feasts, Viking parliaments or early-Christian sermons, their primary task is to elevate people and rites into public view while rooting those events in the very fabric of the landscape. Their long biographies—constantly repurposed yet rarely erased—make them one of the clearest material threads linking prehistoric religion to medieval Christian practice across north-western Europe.

Marlborough Mound, Wiltshire

Marlborough Mound began as a Neolithic water-linked ceremonial platform, was commandeered by Normans for its strategic height, and finally became a show-piece of aristocratic garden theatre.

Marlborough Mound is a Neolithic monument in the town of Marlborough in the English county of Wiltshire. Standing 19 metres (60 ft) tall, it is second only to the nearby Silbury Hill in terms of height for such a monument. Modern study situates the construction date around 2400 BC.

Metric Figure
Height today ≈ 19 m (original probably c. 28 m before landscaping) (en.wikipedia.org)
Basal diameter ≈ 83 m; summit c. 31 m across (en.wikipedia.org)
Earliest construction 2400 BC ± 100 yrs (four radiocarbon samples from 2010–11 coring) (theguardian.com)
Principal phases Neolithic mound → Norman motte-and-bailey (after 1067) → 17th-c. garden focus → modern college landmark

Neolithic “giant”

Coring showed stacked packages of chalk rubble, coloured clays and flinty gravels identical to Silbury Hill, confirming the mound was built in staged lifts over perhaps a century just after 2500 BC. No burial chamber or ramp has been found; like Silbury, it may have been a ritual platform linked to the River Kennet flowing below. (en.wikipedia.org)

Norman royal castle

William I’s surveyors saw a ready-made motte only weeks after the 1066 conquest:

  • Wooden palisade & tower first: A stone shell-keep added c. 1175.
  • Favoured residence of King John and Henry III: Queen Eleanor’s apartments rebuilt in the 1240s. (castlestudiestrust.org)
  • By 1400 the keep was ruinous: The licence to take stone for local building triggered collapse.

Marlborough is the only securely dated case of a Neolithic mound re-used as a Norman motte so far identified. (castlestudiestrust.org)

Stuart & Georgian makeover – the spiral steps

When the castle site became a Seymour country house (1620s), the mound was recast as a garden eye-catcher:

  • A spiral path, 1.5 m wide, makes four circuits to the top, echoing Italian “mount” gardens.
  • A shell-and-flint grotto was tunnelled into the flank, and a water tower planted on the summit to feed cascades. (castlestudiestrust.org)
  • 20th-c. concrete treads on the south-side staircase maintain the route; the Marlborough Mound Trust completed safety repairs and vegetation clearance in 2023. (marlboroughmoundtrust.org)

The garden grotto at Marlborough Mound

Attribute Details
Date & patron Cut into the south-east base shortly before 1735 for Frances Seymour, Countess of Hertford (later Duchess of Somerset). (historicengland.org.uk)
Setting Re-uses the earlier Norman castle ditch. A spiral path climbs the mound above; three ornamental pools were dug in front so reflected light would dance inside the cavity. (en.wikipedia.org)
Structure Flint-rubble façade with a domed, shell-decorated interior. A round-headed niche occupies the rear wall; the vault is just high enough to stand upright (~2 m). The whole chamber is only c. 4 m deep, more an embellished alcove than a tunnel. (historicengland.org.uk)
Water & spectacle Lady Hertford installed a brick water-tower on the summit; a lead pipe fed a cascade that plunged past the grotto mouth and powered a narrow canal in front—turning the Neolithic/Norman mound into an 18th-century water-feature. (en.wikipedia.org)
Purpose Part of the early-Georgian vogue for picturesque garden mounts: intimate “cool retreats” lined with shells, mirrors or minerals, offering sudden shade and theatrical sound of water after walking the sunny spiral. Joseph Addison and Alexander Pope praised exactly such grottoes.
Later history 19th-century college used it as a bicycle shed; by 1980 the flints and shellwork were collapsing. A pupil-led programme (1980s) and the Marlborough Mound Trust (2000-16) stabilised the vault and repointed the façade. (en.wikipedia.org)
Legal protection Listed Grade II as “Grotto at base of south side of Castle Mound” (NHLE 1273151). (historicengland.org.uk)

Key Features

  • Surviving Georgian garden fabric – most of Lady Hertford’s cascades and canals are long gone; the grotto is the sole intact relic of a celebrated ferme ornée garden.
  • Triple-layer biography – Neolithic mound → Norman motte → Georgian shell grotto: few British monuments pack three distinct landscape fashions into a single Earthwork.
  • Hydraulic ingenuity – the summit water-tower (now lost) used the mound’s height exactly as a Renaissance garden mount would, turning prehistoric chalk into a working gravity-feed reservoir.
  • Shellwork rarity inland – unlike coastal shell grottoes (e.g., Pope’s, Margate), Marlborough sits 70 km from the sea; shells were carted specially, underscoring the Countess’s wealth and fashionable connections.

Modern investigation & conservation

Since 2000 the Marlborough Mound Trust (with English Heritage) has:

  • drilled six geological cores, securing the 2400 BC date;
  • stabilised the grotto and rebuilt collapsed steps;
  • opened limited educational access for Marlborough College students. (marlboroughcollege.org, castlestudiestrust.org)

Why Marlborough Mound matters

Significance Details
Twin to Silbury Hill Second-tallest Neolithic mound in Europe, 5 mi down-river from Silbury; both harness the Kennet flood-plain and may have shared water-cult symbolism. (en.wikipedia.org)
Rare biography Only mound known to serve three monumental lives: prehistoric cult focus → royal castle motte → baroque garden mount.
Architectural curiosity The spiral walk and stepped path are early-Stuart landscape engineering, pre-dating better-known garden mounts at Hampton Court.

 

Guide: Spoil Heaps

Waste-mounds & spoil heaps

These are artificial hills made from the unwanted rock, Shale and tailings that come up with coal, metal ore, stone or clay when it is being mined or quarried. Because extractive industry is both deep and long-lived, single collieries or pits can generate tens of millions of cubic metres of spoil; pushed out by locomotive, conveyor or tippler wagon and dumped in successive layers, the piles quickly become a distinctive landform.

From the moment the first Neolithic miner prised nodules of flint out of chalk at Grimes Graves, humans have left piles of unwanted earth and stone beside every hole they dug. These discard mounds—whether waist-high humps of hand-shovelled spoil, or low ridges pushed aside by wooden waggons—are often the only surface traces of extractive episodes that left no standing buildings or other structures. Being able to “read” them is therefore essential background to any landscape study.

What exactly is a “spoil-heap”?

In archaeological terms it is any artificially accumulated mass of overburden or tailings that results directly from subsurface extraction—stone, ore, clay, pigment, salt or peat. Its form depends on three simple variables:

Variable Controls Typical archaeological signals
How the spoil was moved basket, barrow, sledge, cart, rail-tub tiplines, ramps, track ruts
Where it was tipped edge of Shaft, lip of opencut, over cliff cone, fan, linear bank
How long the pit stayed active months, vs. years number of layers, weathering horizons

 

Talus fan:  A small fan-shaped pile where loose spoil naturally slides down.

Cone tip:A pointed heap (like an anthill) formed when carts always dump in the same spot.

Rail-fan embankment: A long, gently curving bank created when tip-wagons move forward a little each time they unload.

Ganister: A very hard sandstone once quarried for lining industrial furnaces (mainly in South Yorkshire and Derbyshire). A “ganister pit” is simply the shallow quarry left by that work.

How mining activity changed over time

Stone Age and Bronze Age.

Early miners worked with antler picks, stone hammers and baskets. They tipped the waste right beside the hole. The result is a low, lumpy mound, usually no more than a metre or two high. You can still see these soft heaps around flint mines such as Grimes Graves in Norfolk.

Iron Age and Roman times.

By the Iron Age, people were using small carts or sledges pulled by people or animals. Spoil was thrown out along the line of the trench, creating a shallow ridge rather than a simple lump. The Romans went further: where water was handy, they sometimes washed whole hillsides with stored water to expose ore. The flushed-out rubble forms wide fans or gullies below the workings—good examples survive at the Roman gold mines of Las Médulas in Spain and at Dolaucothi in Wales.

Medieval period.

Water power, horse power and simple rails allowed deeper shafts and larger open cuts. Waste could be hauled a short way from the pit and dumped at a fixed point, load after load. Over decades this built a small cone-shaped hill, a familiar sight in many medieval lead and iron districts. In Brigantia country you may meet these pointed tips beside old lead hushes in Swaledale.

Early modern (before heavy industry).

From the sixteenth to the early nineteenth century, wooden or iron rails, bigger horse carts and the first steam engines let mines handle still more material. Spoil-heaps of this date are larger cones or long banks with wheel-ruts or rail beds still visible on their flanks.

Period / power source Haul method Spoil form European examples
Neolithic–Bronze Age Human power – baskets & hides Small, irregular talus fans hugging the trench; sometimes rampart-like rings round vertical shafts Flint mine spoil at Krzemionki (Poland); copper prospect scatters in the Austrian Tauern
Iron Age–Roman Pack animals & two-wheeled tip carts Elongated embankments flanking opencast fronts; spoil occasionally graded to form working platforms Iron pits on the Weald (UK); hydraulic gold waste at Las Médulas (Spain)
Early-Medieval Hand barrows, timber sledgeways Low, lumpy hillocks beside bloomery shafts; often reused as later field lynchets Early‐medieval iron “scoriae” mounds in Lorraine; lead hush spoil in the Pennines
High-Medieval–Tudor Horse tramways, stackings over shaft mouths Steeper conical tips up to 6–8 m as ore volumes rise; ragged trackways visible on LiDAR Lead–silver tips in the Erzgebirge; coal “hillocks” of North Derbyshire
Early-Industrial (17 th – early 19 th c.) Wooden or iron plate-way trucks, water-balance lifts Regular “chevron” lines or rail-fan embankments; first signs of ash-rich black spoil Charcoal-iron tips of Styria; bell-pit ridges across Durham and Northumberland

Why they matter

  • Palimpsest recognition – Many sites re-occupy earlier extraction grounds (e.g., Bronze-Age Hushing scarps reused for iron-ore diggings), so recognising a low Iron-Age cart-tip against an earlier talus bank is key to correct phasing.
  • Resource economy – Spoil chemistry (hammer-scale, Slag flecks, Ochre stains) tells us what ores or pigments local people valued and how they processed them.
  • Territorial signals – In upland Swaledale or Nidderdale, linear tips often double as visual claims across valley floor grazing, tying industrial practice to land-holding strategies.

Tips for disentangling mixed mounds

Check the layering: prehistoric hand-dump tends to show thin, unsorted chalk or clay layer lenses; high-medieval cart tips build thicker, better-sorted layers.

Look for track imprints: twin ruts or sleeper-pits betray late horse-tram spoil routes slicing across an earlier tip.

Use LiDAR: subtle slope-breaks and zigzag haul ramps appear even under pasture, helping to separate conical “basket tips” from later rail fans.

Ochre mine in the Lion Cavern in Eswatini southern Africa - Credit - Jörg Linstädter

Ochre mine in the Lion Cavern in Eswatini southern Africa – Credit – Jörg Linstädter

Chronology of mining development

Date Break-through What it unlocked
c. 40 000 BCE Ochre quarry at Lion Cavern in Eswatini (formerly Swaziland) World’s earliest evidence of deliberate mineral extraction for pigment.
c. 3000 BCE Timna (Israel), and Cypriot copper mines Large-scale bronze metallurgy needs organised mining & smelting.
c. 100 CE Roman hushing & hydraulics at Las Médulas (Spain) Water power strips overburden & washes gold—first “industrial” hydraulics.
1627 Gunpowder blasting reaches German & Swedish metal mines Rock-breaking no longer relies on firesetting; galleries drive faster. (en.wikipedia.org)
1712 Newcomen steam Engine pumps flooded shafts in England Enables mines deeper than 30 m.
1770s Cornish high-pressure engine (Watt → Trevithick) Doubles efficiency; drives man-engines & winding gear. (cdn.cornishmining.org.uk)
1867 Dynamite patented by Nobel A safer, more powerful explosive replaces black powder. (en.wikipedia.org)
1880s Pneumatic rock drills Mass tunnelling & hard-rock stopes.

 

Guide: Hillfort Mounds of Europe

Hillfort mounds

Hillfort mounds are elevated, man-made (or heavily modified) earthen platforms whose crests carry ramparts, palisades or stone walls and whose flanks are protected by one or more surrounding ditches. They appear in most parts of Europe from the Late Bronze Age (c. 11th century BCE) but flourish during the Iron Age (8th century BCE – 1st century CE). Many were re-used or newly founded in the Roman and early-medieval periods. Their positions—usually on hilltops, spurs or sea-cliffs—gave wide views for surveillance and emphasised the power of the communities that built them. Excavation shows they could serve as defended farmsteads, seasonal refuges, tribal centres, craft hubs and places of assembly or ritual. (en.wikipedia.org)

Building techniques

Typical construction begins with a ditch dug just below the brow of the slope; the spoil is thrown inward to form a bank (rampart). That bank may be:

  • Pure earth packed into a steep façade.
  • Timber-laced “box” rampart: parallel timber walls infilled with earth and rubble, known across Britain and Atlantic Europe.
  • Timber-framed stone rampart such as the murus gallicus of Gaul or the Bavarian-Czech Pfostenschlitzmauer (“post-slot wall”) of the Oppida, where vertical posts pierce a stone facing. (en.wikipedia.org)
  • Vitrified wall: a stone rampart deliberately fired until outer courses fuse, best known in Scotland but now recognised more widely. (en.wikipedia.org)

Gateways are often elaborately in-turned, sometimes with staggered passages or horn-works to slow attackers. Inside, round or rectangular houses, granaries, workshops and livestock pens cluster against the rampart, leaving a central hollow or street-grid (in the largest sites).

Multivallate Ringfort at Rathrar (Rathbarna Enclosure Complex), Co Roscommon, Ireland

Multivallate Ringfort at Rathrar (Rathbarna Enclosure Complex), Co Roscommon, Ireland” by West Lothian Archaeological Trust (Jim Knowles, Frank Scott and John Wells) is licensed under CC BY-SA 4.0

Manching oppidum model

Manching model 1” by Wolfgang Sauber is licensed under CC BY-SA 3.0

Common hillfort types across Europe

Below is a practical typology that archaeologists and heritage managers use; many individual forts combine features from several categories.

Type Core features & rampart layout Main distribution Classic examples
Univallate hillfort Single circuit of bank + ditch; compact ( < 5 ha) Widespread, especially early Iron Age Britain, Ireland, Low Countries Solsbury Hill (England), Navan Fort inner enclosure (N. Ireland) (en.wikipedia.org)
Multivallate hillfort Two – six concentric ramparts; huge labour investment; often later in sequence Southern Britain, Brittany, Central Europe Maiden Castle (England), Monte Bernorio (Spain) (en.wikipedia.org)
Promontory fort Natural cliffs on three sides; artificial rampart only across neck Atlantic façade of Ireland, Cornwall, Brittany; Baltic islands; inland river spurs Dunbeg (IE), Tintagel (UK), Cronk ny Merriu (IoM) (en.wikipedia.org)
Contour / Plateau fort Ramparts trace hillside contours or enclose a flat summit; may be univallate or multivallate Scotland, Wales, Central Europe, Alpine zone Brent Knoll (UK), Ipf (DE) (en.wikipedia.org)
Oppidum (plural oppida) Very large (≥ 20 ha) late Iron-Age fortified towns with timber-framed stone walls, gateways, street plans and specialist quarters Central & Western Europe, esp. Hallstatt & La Tène cultural zones Manching (DE), Bibracte (FR), Heuneburg (DE) (brewminate.com, en.wikipedia.org)
Castro hillfort Oval/round stone-walled enclosures with clusters of round-houses; often terraced; long use c. 9th c BCE–1st c CE N-W Iberian Peninsula (Galicia & N Portugal) Citânia de Briteiros, Castro de San Vicenzo (academic.oup.com, brown.edu)
Vitrified hillfort Stone rampart glassified by intense fire; causes debated (defence, ritual destruction) Scotland, western France, SW Germany Tap O’ Noth (UK), Saint-Céneré (FR) (en.wikipedia.org)
Slavic gord / burgwall Timber-earth ring-wall with palisade and outer moat, 6th – 12th c CE; evolves into early castles Poland, Czech lands, East Germany, Ukraine Biskupin (PL), Groß Raden (DE), Mikulčice (CZ) (en.wikipedia.org)

Key concepts

  • Shared idea, local expression – building a mound, ditch and rampart is a simple yet powerful strategy that different cultures adapted to their terrain, materials and social needs.
  • Size tracks social complexity – from small univallate farmsteads to oppida of 100 ha, the scale of works mirrors political consolidation in the late Iron Age.
  • Re-use and memory – many medieval castles, Norman mottes or Early Christian monasteries sit inside older hillfort circuits, showing these Earthworks remained potent landmarks long after their original builders were gone.
  • Place in mythology – Many hillforts have a rich local mythology, often involving dragons, King Arthur, of the Devil. For example, the legend of Caer Caradoc.
  • Uncertain primary purpose: Hillforts were long assumed to be the defences needed by war-like tribal kingdoms. However, more recently, it has been recognised that most never saw a fight, and are more related to earlier “ritual” monuments such as barrow and cursus type monuments that this understanding of a defensive primary purpose is now much less certain as a primary purpose.

Timeline of hillfort development

Timeline of hillfort development

Reading the timeline

Left of “0” = BCE; right = CE.

Bars show when each construction/usage phase was most widespread (regional outliers exist).

Phase Approx. dates Core innovations & significance Typical regions
Proto-hillforts (Late Bronze Age) 1300 – 800 BCE First ditch-and-bank enclosures; often single rampart; linked to Urnfield/Lusatian cultures and rising conflict. Central Europe, Alpine zone, Po Basin, Bohemia
Early Iron-Age hillforts (Hallstatt) 800 – 450 BCE Taller timber-laced ramparts, in-turned gates; some nucleated “seat of chiefs” sites. Alpine forelands, Danube valley, Atlantic façade of Britain/Ireland
Early La Tène hillforts 450 – 250 BCE New murus gallicus and pfostenschlitzmauer wall types; more planned interiors; craft & minting zones. Gaul, Hunsrück-Eifel, SW Germany, Czech lands
Oppida (large La Tène fortified towns) 250 – 50 BCE Urban-scale (20–150 ha), rectilinear streets, gateways with annexes; act as tribal capitals & trade hubs. Central & W. Europe, from Spain to Bohemia
Roman-period refortifications 50 BCE – 300 CE Some hillforts demolished; others get stone towers, signal-stations or become legionary bases. Britain, Upper Rhine, Danube limes
Post-Roman / Sub-Roman reuse 400 – 600 CE Shrinking populations re-occupy legacy ramparts as refuges and power bases; e.g., “dark-age” forts in Wales & Cornwall. Atlantic Britain, Brittany, Massif Central
Slavic gords & early-medieval forts 600 – 1000 CE Timber-earth ring-walls with outer moats; nuclei for early states (Bohemia, Polonia). Poland, Czech & Slovak lands, N-E Germany, W Ukraine
Viking Age ring-forts 900 – 1050 CE Geometric circular forts (Trelleborg type), heavy plank revetments, radial streets; royal military bases. Denmark, Scania, Zealand, Skåne

Big-picture takeaways

Continuity through change: While rampart engineering evolves from simple earthen banks to timber-laced and stone facings, the underlying idea of a raised, ditched circuit remains constant for nearly two millennia.

Social scale expands: Forts grow from 1 to 5 ha farmstead refuges to 100 + ha oppida as tribal confederations form, then shrink again in turbulent post-Roman centuries before re-emerging as proto-cities (gords) and state fortresses (Viking ring-forts).

Technological exchange: Construction techniques (e.g., murus gallicus, vitrified walls) spread along trade and conquest routes, showing how hillfort builders watched—and copied—one another across great distances.

Guide: Barrows

What Is a Barrow?

A barrow is a mound of earth and/or stones raised over a grave or group of graves. Used from the Neolithic through to the Iron Age (roughly 4000 BCE to 500 CE), barrows were often constructed to honour elite individuals, such as tribal leaders, warriors, or chieftains. They are frequently found singly or in cemeteries known as barrow fields.

Barrows vary in shape, construction, and size, and these differences can reflect chronological developments, regional styles, or cultural practices.

Main Types of Barrows

Round Barrows

These are circular mounds of earth or stone, often with a central burial. They are common from the Late Neolithic through the Bronze Age, and usually contain one or more graves (inhumations or cremations), often within a central cist, pit, or chamber. They are found widespread across Europe, especially in Britain, Scandinavia, and Central Europe.

Example: The Wessex Round Barrows, near Stonehenge, England, are classic Bronze Age barrows often associated with elite burials and rich grave goods.

Long Barrows

These are elongated mounds, often hundreds of feet in length. They date mainly to the Neolithic period (mainly 4000–3000 BCE). They typically contain multiple burials, often collective, sometimes in chambered tombs. Long Barrows are found in western and Northern Europe, including Britain, France, and Scandinavia.

Example: West Kennet Long Barrow in Wiltshire, England, is a prominent Neolithic monument with a long stone-built burial chamber within the mound.

Bell Barrows

These are a subtype of Round Barrow with a prominent mound separated from an encircling ditch by a flat platform (berm). They are mainly Bronze Age in date, and are often associated with single, prestigious burials and grave goods. These are particularly common in southern England.

Disc Barrows

These have low, wide circular features defined by a ditch and bank with one or more small central mounds. They date from the Later Bronze Age, and are frequently ceremonial, with fewer or no burials. They are found mostly in southern Britain and are rare elsewhere.

Oakley disc barrow panorama

Oakley Disc Barrow” by JimChampion is licensed under CC BY-SA 4.0

Ring Barrows

These consist of a ring-shaped bank and ditch, with little or no central mound. They date from the late Bronze Age into the Iron Age and may have had ceremonial or symbolic functions, possibly as cenotaphs. They are found in Ireland, Britain, and northern France.

Square barrows

These are square (or sometimes rectangular) ditched enclosure, normally 6-12 m across, raised into a low mound with a single central grave. The ditch is dug first; its spoil provides the mound core, so most barrows now survive only as cropmarks. (historicengland.org.uk).

The earliest examples belong to the Middle–Late Iron Age (c. 5th–1st century BC), contemporary with La Tène culture on the Continent and the Arras tradition in East Yorkshire. A few later, early-Roman imitations exist. Square barrows are also known from the Roman and Scottish Pictish cultures.

Usually an inhumation is placed on its back or side; grave-goods range from plain pots to chariots, weapons, brooches and horse gear.

Steppe Kurgans (Eurasian Tumuli)

These are large, often monumental burial mounds found across the Eurasian steppe. They date from the Bronze Age to the early medieval periods, and are understood to be elite burials of nomadic tribes (e.g. Scythians, Sarmatians) with rich artifacts and horse burials. They can be found in Eastern Europe, especially Ukraine, southern Russia, and into Central Asia.

Example: The Royal Kurgans of the Scythians in Ukraine, such as the Solokha and Chertomlyk mounds, contain vast underground chambers and gold-laden burials.

Scythian capital and royal kurgans

“Scythian capital and royal kurgans” by Janmad is licensed under CC BY 3.0

royal kurgans

File:Царський курган 007.jpg” by Anatoly Shcherbak is licensed under CC BY-SA 3.0

Regional Variations

Britain and Ireland: Strong emphasis on Neolithic long barrows and Bronze Age round barrows. Barrow cemeteries often align with major ritual landscapes, like Stonehenge or Avebury.

Scandinavia: Includes large burial mounds (e.g., Gokstad and Oseberg in Norway), often associated with ship burials in the Viking Age.

Central Europe: Rich Hallstatt culture barrows in Austria and Germany, often with chariot burials and luxury goods.

Iberian Peninsula: Fewer classic barrows; instead, Megalithic Tombs with earthen covering are more typical.

Eastern Europe: Kurgan-style mounds dominate, associated with Indo-European migrations and later nomadic empires.

Purpose and Significance

Barrows served not only as graves but also as:

  • Territorial markers
  • Religious or ceremonial sites
  • Symbols of status and memory

They remain important archaeological sites today, revealing burial customs, social hierarchies, and long-distance trade through the study of grave goods.

Timeline of Barrow development in Europe

Chart of barrow development through time

How to read the chart

  • Years to the left of “0” are BCE, years to the right are CE.
  • Each horizontal bar shows when a particular barrow-building tradition was most active across Europe. (Local outliers exist, but these ranges capture the main pulse of construction in the archaeological record.)
Tradition Approx. span Key reference
Early Neolithic long barrows c. 4000 – 3000 BCE (en.wikipedia.org)
Late Neolithic passage-tomb barrows c. 3200 – 2500 BCE (en.wikipedia.org)
Early Bronze Age round barrows c. 2200 – 1100 BCE (heritagecalling.com)
Nordic Bronze Age barrows c. 1750 – 500 BCE (en.wikipedia.org)
Hallstatt Iron-Age barrows c. 800/700 – 450 BCE (britannica.com)
La Tène Iron-Age barrows c. 450 – 1 BCE (en.wikipedia.org)
Roman-period barrows c. 50 – 200 CE (historicengland.org.uk)
Anglo-Saxon / Migration-period barrows c. 500 – 700 CE (en.wikipedia.org)
Viking Age barrows c. 800 – 1050 CE (en.wikipedia.org)

What the timeline shows

A very long tradition – from the first Neolithic communal tombs (long barrows) right through to high-status Viking Age mounds, the basic idea of commemorating the dead with an earthen or stone mound persisted for almost five millennia.

Changing meanings – while Neolithic mounds emphasised collective ancestors, later Bronze-Age and Iron-Age barrows increasingly marked individual or elite burials, reflecting shifts in social hierarchy and belief.

Regional peaks :

  • Britain & Atlantic façade: strong Neolithic and Early Bronze-Age phases.
  • Central Europe: flourishing Hallstatt and La Tène “princely” barrows.
  • Scandinavia: a remarkably long Nordic Bronze-Age barrow tradition that blends into Viking Age ship-mound burials.

Interruptions & revivals – Roman fashions temporarily dampened barrow-building in many areas, but early-medieval elites (Anglo-Saxon, Slavic, Scandinavian) revived the custom as statements of power and identity.

Key observations

Era Main concentration(s) Notes
Early Neolithic long barrows Britain, northern France, Denmark, north Germany, Poland First communal monuments; linked to early farming.
Passage-tomb barrows Ireland, Brittany, Cantabrian coast, Orkney & northern Scotland Characterised by megalithic art and sophisticated astronomic alignments.
Early Bronze-Age round barrows Atlantic façade, North European Plain, parts of Iberia & Central Europe Often single burials with metal grave goods.
Nordic Bronze-Age barrows Denmark, south Sweden, coastal Norway Typically placed on ridges overlooking sea routes.
Hallstatt & La Tène barrows Alps to Central Europe “Princely” graves with weaponry, wagons, imported luxuries.
Early-medieval & Viking barrows England (eastern counties), Scandinavia, Iceland Ship burials and elite mounds revive the tradition after Roman lull.

Guide: SAR Doppler Tomography

SAR plotting a volcanic eruption - Scott Manley

SAR plotting a volcanic eruption – Scott Manley

SAR Doppler Tomography

Synthetic-Aperture Radar (SAR) already relies on Doppler shifts: echoes from scatterers in a side-looking radar beam have slightly different frequencies as the platform flies past, and focusing those micro-shifts yields a two-dimensional image. Doppler (or Tomo) SAR takes the idea one step further. By collecting a stack of SAR images from slightly different flight tracks or look angles, it treats the Doppler-frequency axis itself as an aperture in elevation.

Cover image for a Scott Manley video on SAR
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The above video, from Scott Manley, explains SAR (prior to doppler), and compliments this article by serving as an introduction to the subject.

Setting the scene

When archaeologists talk about radar they usually mean a device that sends out a burst of radio-waves and times the returning echo. Synthetic-Aperture Radar, or SAR, is a special form that flies on an aircraft or a satellite. Instead of taking a single snapshot, the sensor keeps transmitting while it moves; later, a computer knits all those echoes into a single “synthetic” antenna hundreds or even thousands of metres long. The result is a map whose sharpness rivals optical photographs but that works day or night and through cloud, smoke or forest canopy.

Every echo carries two pieces of information:

  • its amplitude (how strong the reflection is)
  • its phase (the tiny shift in wavelength that measures how far the wave has travelled).

Because the aircraft is moving, echoes from objects ahead and behind the beam arrive with slightly different frequencies. That frequency shift is called Doppler. By treating the Doppler spectrum as if it were another lens, engineers can focus not just a flat picture but a three-dimensional tomographic slice. The technique is therefore known as SAR Doppler Tomography (or simply TomoSAR).

Three geometric terms matter throughout:

  • Wavelength (λ) – the physical length of one radio wave. Longer wavelengths (P-band ≈ 70 cm, L-band ≈ 23 cm) penetrate leaves, light forest or dry sand better than short wavelengths (C-band ≈ 6 cm, X-band ≈ 3 cm).
  • Baseline (B⊥) – the sideways separation between two flight tracks. The wider this gap, the finer the vertical resolving power of the tomographic reconstruction.
  • Look Angle (θ) – the tilt between the beam and the vertical. It controls how echoes stack up in depth.

After focusing, the computer fills a 3-D grid of tiny boxes called voxels (volume pixels) with Back-scatter strength. One Voxel might represent the forest canopy, another the bare soil beneath, or—if conditions are perfect—the roof, walls and foundations of a buried structure. The clarity of each layer depends on Coherence (how similar the phase of successive echoes remains) and on how far the radio waves can travel through vegetation or soil before they fade.

Wavelengths used

Radar band Central frequency (GHz) Wavelength (cm) Typical satellite / airborne sensors Vegetation / soil penetration* TomoSAR Height Resolution achievable**
X-band 8–12 GHz 3.1–2.5 cm TerraSAR-X / TanDEM-X, COSMO-SkyMed, ICEYE Negligible; only thin canopy, no ground 20–30 m from single-sat stacks; ≤10 m with along-track/bistatic baselines
C-band 4–8 GHz 7.5–3.8 cm Sentinel-1, RADARSAT-2, Envisat ASAR Light foliage; centimetres into dry sand 10–20 m (constellation stacks)
S-band 2–4 GHz 15–7.5 cm NASA NISAR (launch 2025), NovaSAR-1 Partial canopy, tens of cm into dry loam 5–10 m (multi-baseline airborne)
L-band 1–2 GHz 30–15 cm ALOS-2 PALSAR-2, NISAR, SAOCOM, UAVSAR Full canopy; ~30 cm into dry, coarse soils 3–5 m with 1–3 km airborne baselines; 10 m from satellite stacks
P-band 0.23–0.47 GHz 130–64 cm DLR F-SAR, NASA UAVSAR-P, ESA BIOMASS (planned) Penetrates >50 m canopy; up to ~60 cm in very dry sand 1–3 m (airborne baselines of several km); 5 m expected for BIOMASS constellation

* Penetration depths assume low soil moisture and low salinity; water-logged or clay-rich ground drastically reduces reach.
** Height resolution figures are rule-of-thumb values derived from Δh ≈ λ R ⁄ (2 B⊥ sin θ) for typical ranges and available baselines.

Common terms

Synthetic-Aperture Radar (SAR):  Side-looking radar flown on aircraft or satellites; by combining echoes gathered along the flight path it simulates an antenna hundreds of metres long and produces metre-scale images day or night, through cloud, smoke or vegetation.

Doppler Shift: The tiny change in echo frequency caused by the platform’s motion relative to scatterers ahead or behind the beam; SAR processors exploit these shifts to focus detail along track and, in tomography, to separate echoes coming from different heights.

Tomographic SAR (TomoSAR): A stack of slightly offset SAR passes treated as a vertical aperture so that the Doppler spectrum can be inverted, voxel by voxel, into a three-dimensional back-scatter map.

Voxel: The smallest 3-D element in a tomographic cube; it records echo strength from a specific azimuth-range-height cell, analogous to a pixel in 2-D imagery.

Wavelength (λ): Physical length of one radar wave; long wavelengths (L-band ≈ 23 cm, P-band ≈ 70 cm) penetrate foliage or dry sand far better than short ones (X-band ≈ 3 cm).

Baseline (B⊥): The sideways separation between two flight tracks; greater baselines widen the synthetic vertical aperture and sharpen height resolution.

Look Angle (θ): The tilt between the radar beam and the vertical; together with baseline and wavelength it controls the achievable vertical resolution Δh ≈ λ R / (2 B⊥ sin θ).

Coherence: A measure of how little the radar phase changes between repeated passes; high coherence is essential for sharp tomographic reconstruction and deformation mapping.

Phase: The fractional part of a radar wavelength returned by a target; phase differences underlie SAR focusing, interferometry and tomographic height separation.

Amplitude (Back-scatter): Echo strength returned from a target; variations map surface texture, moisture and roughness, and populate voxel intensities in TomoSAR.

Interferometric SAR (InSAR): Technique that compares phase between two coherent SAR images to measure height or surface motion; forms the 2-D precursor to full 3-D TomoSAR.

D-TomoSAR — Differential Tomographic SAR; combines InSAR phase change with 3-D voxel separation to monitor millimetre-scale deformation on specific height layers (e.g., building façades).

Beam-forming Algorithm (Capon, MUSIC, RIAA): Mathematical filters that convert Doppler-frequency data into height profiles; newer high-resolution methods (e.g., RIAA) halve vertical error compared with classical Fourier focusing.

Penetration Depth: Maximum subsurface reach of a radar pulse; in very dry, quartz-rich soils P-band may penetrate up to \~60 cm, while vegetation penetration can exceed 50 m.

Height Resolution: Smallest vertical separation TomoSAR can distinguish; ranges from \~3 m for airborne P-band with multi-kilometre baselines to \~30 m for single-satellite X-band stacks.

The technology itself, is quite technical, and is likely to have developed further, by the time you read this, but with those ideas: Synthetic aperture, Doppler shift, tomography, wavelength, baseline, look angle, voxel, coherence and penetration, in place, the reader should get a good understanding both of the technology and of it’s application and limitation.

Technical Discussion

This next section shows in detail how engineers turn raw radar echoes into a 3-D model, and the following sections explore what that model has already revealed about standing monuments, jungle-hidden cities and shallow desert ruins.

Making height-focusing feel less like rocket science

If you think of ordinary SAR as shining a very thin torch-beam sideways from an aircraft: while the aircraft moves forward, every ground object briefly sits in the beam and the echo you record contains a tiny frequency shift (its Doppler “note”). Add all those notes together in software and you “focus” a sharp 2-D picture.

Tomographic SAR does exactly the same thing, but with several parallel flight paths, so you hear each object singing at a slightly different pitch every time. If you now stack all those echoes you have, in effect, recorded a little Doppler melody that changes with height. “Playing the melody backwards” (the mathematical term is inverting the spectrum) lets a computer place echo-strength into thousands of 3-D bricks called voxels. The algorithms that perform this reverse process—Fourier beam-forming, or the higher-definition Capon, MUSIC and RIAA filters—differ only in how cleverly they separate the overlapping notes; to the user they all end up filling a 3-D cube of brightness.

Why a radar’s “eyeglass” has limits

A camera’s sharpness depends on lens diameter; for TomoSAR the equivalent “lens” is the sideways gap between the highest and lowest flight lines, called the perpendicular baseline (B⊥). The focusing rule is:

    Δh ≈ λ R ⁄ (2 B⊥ sin θ)

  • λ – radar wavelength: longer waves improve penetration but coarsen resolution.
  • R – slant range: the straight-line distance from sensor to target (hundreds of kilometres for a satellite, tens for an aircraft).
  • B⊥ – total vertical spread of the flight paths; the wider the spread, the finer the vertical “slice”.
  • θ – look angle: a steep look (large θ) helps resolution; a very shallow look blurs it.

Two concrete examples

  • Satellite X-band stack (TerraSAR-X)
    • λ = 3 cm, R ≈ 700 km, B⊥ ≈ 2 km, θ ≈ 35°.
    • Δh ≈ (0.03 m × 700 000 m) ⁄ (2 × 2 000 m × 0.57) ≈ 18 m.
    • Result: you can separate a city roof from the street, or a canopy from the ground, but you will not pick out individual forest layers.
  • Airborne P-band campaign over rainforest
    • λ = 70 cm, R ≈ 10 km, B⊥ ≈ 3 km (dozens of tightly controlled tracks), θ ≈ 45°.
    • Δh ≈ (0.70 m × 10 000 m) ⁄ (2 × 3 000 m × 0.71) ≈ 1.6 m.
    • Result: separate the tree-tops, understory and the bare soil with enough clarity to map ancient causeways hidden under 50 m of jungle.

Accuracy in the real world

Forests: multi-baseline P-band surveys in Gabon and Cambodia quote height RMSE of 2–4 m when checked against airborne LiDAR.

Urban heritage: twelve-scene TerraSAR-X stacks over Milan reproduce façade heights within ±1 m and detect subsidence of <2 mm / year.

Desert archaeology: experimental L-band TomoSAR in Egypt has outlined buried walls under 40 cm of dry sand, though still at a coarse 8-m vertical grid.

So, while the maths hides inside specialist software, the take-away is simple: longer wavelengths plus wider baselines equal sharper and deeper 3-D views, and even the “blurrier” satellite stacks are already accurate enough to monitor buildings or strip the canopy off extensive archaeological landscapes.

Technical summary

A 3-D voxel map of back-scatter is then reconstructed by inverting the Doppler spectrum with a Fourier beam-former or high-resolution spectral estimator such as Capon, MUSIC or the more recent RIAA algorithm (sto.nato.int, mdpi.com). The achievable vertical (height) resolution obeys an optical-style formula Δh ≈ λ R⁄(2 B⊥ sin θ), where λ is wavelength, R slant range, B⊥ the total perpendicular baseline and θ the look angle (earth.esa.int); centimetre wavelengths and kilometre-scale satellite baselines give ~30–50 m, while airborne P-band campaigns with tens of baselines routinely reach 3–5 m.

Workflow in outline

  • Acquire a coherent stack (typically 5–50 single-look-complex images) from repeat-pass, bistatic or along-track channels.
  • Precisely co-register and compensate for platform motion to a common phase origin.
  • Form the Doppler spectral cube and apply beam-forming / spectral inversion to retrieve the elevation profile for every azimuth-range pixel.
  • Optionally apply differential processing to isolate deformation or slow motion (D-TomoSAR).

Where it has been used

  • Forests and biomass – L- and P-band TomoSAR campaigns by DLR, NASA UAVSAR and ESA’s AfriSAR have mapped canopy layers and ground topography through >50 m tropical forest; recent P-band tests report canopy-height RMSEs of 2–6 m against LiDAR (mdpi.com, sciencedirect.com).
  • Urban 3-D mapping – TerraSAR-X stacks over Berlin, Munich and Milan resolve individual building façades and detect millimetre-scale subsidence; height differences compared with airborne laser scans are usually within 1–3 m (engineering.purdue.edu, researchgate.net).
  • Cryosphere & topography under vegetation – multilook P-band apertures recover glacier stratigraphy and bare-earth surfaces beneath forest canopy.
  • Infrastructure/heritage monitoring – phase-based Doppler tomography of COSMO-SkyMed images has revealed sub-millimetre micro-vibrations inside the Khufu pyramid, producing a 3-D map of hidden chambers (mdpi.com).
  • Experimental marine & coastal work – along-track Doppler tomography is being trial-led to image wave fields and coastal subsurface geology (oceanova.nz).
SAR Penetration - Scott Manley

SAR Penetration, note the minimal depth penetration in contrast to SAR Doppler Tomography – Scott Manley

How well does it work?

Vertical resolution is limited by wavelength and total baseline; airborne P-band or low-orbit bistatic constellations can reach 1–3 m, whereas single-platform X-band satellites seldom do better than 30 m.

Height accuracy (bias/RMSE) depends on signal coherence, vegetation density and algorithm choice. In mixed temperate conifer sites an RIAA processor at L-band achieved 2.0 m RMSE in canopy height; a conventional Capon solution on the same data gave 6 m (mdpi.com). Urban point-cloud studies with TerraSAR-X routinely meet ±1 m when control points are available (engineering.purdue.edu).

Limitations include temporal decorrelation in leafy forests, layover in steep terrain, sensitivity to baseline errors, and high computation cost for large stacks; advanced sparse-recovery and machine-learning solvers are an active research front (link.springer.com).

The future

ESA’s BIOMASS P-band mission (launch planned 2025) and the proposed Tandem-L constellation are designed with multi-baseline geometries precisely to exploit Doppler SAR tomography for global 3-D biomass, deformation and surface-change mapping. With those satellite stacks expected to refresh every 7–16 days, D-TomoSAR will shift from experimental campaign tool to routine Earth-observation workhorse over the next decade.

SAR use for Archaeology - Scott Manley

SAR use for Archaeology – Scott Manley

Use in Archaeology

For archaeology, the technique has been applied in two quite different ways.

Monitoring of standing monuments

The first and most mature use is for monitoring standing monuments. With a long stack of very high-resolution satellite scenes, tomographic processing can separate the echoes that come from the façades, the roof and the ground around a building, effectively turning a side-looking radar into a three–dimensional laser scanner.

The TerraSAR-X stacks that were raised over Milan, Berlin and Munich resolve individual stories on masonry towers and track sub-millimetre subsidence month by month; comparisons with laser scans show the height values are usually within about one metre of the true surface and the measured rates of movement match classical levelling to within a millimetre a year. These same data are now used by conservation teams to decide where to grout, underpin or restrict visitor numbers.

Buried or canopy-covered archaeology

The second, newer strand concerns buried or canopy-covered archaeology. By flying a radar that works at a very long wavelength—twenty-three centimetres at L-band or sixty to seventy centimetres at P-band—and by repeating the flight on dozens of slightly shifted tracks, researchers can treat the Doppler frequency axis as a vertical aperture and reconstruct a voxel model of everything that reflects in the first ten to fifteen metres above the true ground.

In tropical forests the method pulls two quite independent surfaces out of the data cube: one is the canopy top; the other, tens of metres lower, is the bare earth. When the DLR and NASA teams applied P-band TomoSAR to the Angkor and Caracol catchments it delivered under-canopy digital-terrain models whose vertical error against ground survey was about three to five metres; the resulting maps revealed long rectilinear embankments, reservoirs and causeways that had never been seen in the jungle before. (caracol.org) Similar experiments on the gravel terraces north of the Nile have detected buried wall lines under half a metre of wind-blown sand, though that work is still in conference proceedings rather than a full peer-reviewed paper.

Penetration into vegetation

Penetration into vegetation is therefore excellent—the radar sees right through a fifty-metre canopy at P-band—but penetration into soil is modest. In very dry, quartz-rich sand a P-band pulse can reach something approaching one metre; in damp loam or clay the depth falls to a few centimetres, and practically no energy survives to be tomographically focused. That is why the clearest sub-surface successes so far come from hyper-arid desert margins or from gravelly terraces where the water table is deep.

A cautious rule of thumb from the experimental campaigns is that you may expect reliable mapping of structures buried up to half the operating wavelength—so perhaps thirty centimetres at L-band and sixty centimetres at P-band—provided the soil is dry, salts are low, and the target surface is fairly extensive. Where those conditions hold, height resolution inside the ground layer is on the order of the vertical resolution in the air, namely three to five metres for airborne P-band baselines of a few hundred metres and perhaps thirty metres for present single-platform X-band satellites. (onlinelibrary.wiley.com, sciencedirect.com)

Proven tool, still being developed

SAR Doppler tomography is already a proven tool for millimetre-scale deformation studies on standing heritage and a promising, though still experimental, way to strip forest canopies from archaeological landscapes and to glimpse shallow masonry in desert terrain. The degree of ground penetration is governed less by the mathematics of tomography than by physics: the longer the wavelength and the drier the soil, the further the pulse can travel and the more archaeological detail it will return.

Guide: Classification of Henge Monuments

Classification of Henge Monuments

Introduction

Archaeologists use the word “henge” for later-Neolithic and earliest Bronze-Age earthen rings whose ditch lies inside the bank, creating a deliberately bounded interior. The term itself was coined in 1932 by Kendrick; it was refined in the 1950s by Richard Atkinson, whose system still frames most discussion.

Henge Classifications

Atkinson divided true henges into three classes according to how many gaps the builders left through the Earthwork. Class I has only a single entrance; Class II has two opposed entrances; Class III has four, facing one another in pairs. Later writers kept the same basis but recognised subgroups when more than one concentric ditch is present, so we now meet labels such as “Class IA” for a single-entrance ring with a double ditch, or “Class IIA” for a two-entrance ring that also has multiple ditches. (en.wikipedia.org, nessofbrodgar.co.uk)

The Term – Hengiform

Because some monuments are either much smaller or vastly larger than the classic examples, further descriptive labels have grown up. Geoff Wainwright introduced “hengiform” in 1969 for diminutive rings only five to twenty metres across; they behave like mini-henge shrines rather than full ceremonial arenas. At the opposite extreme, scholars speak of “henge enclosures” or “super-henges” when the banked circuit exceeds three hundred metres, as at Durrington Walls or Marden. All of these variants keep the inner ditch as their defining feature.

Classifying Factors

Size and entrance number are not the only traits that vary. Some henges are built entirely of redeposited gravel or cobbles with no ditch at all, as at Mayburgh and Catterick; others combine bank, ditch and a ring of timbers or stones, while some, like Thornborough, sit within wider linear Earthworks. Attempts to force every ring into a rigid class scheme can therefore be misleading, and recent syntheses emphasise that “henge” is a morphological convenience, not a guarantee of shared function. Even so, the entrance-based classes remain a useful shorthand when comparing monuments or mapping their distribution, which is densest in lowland England and southern Scotland but extends from Orkney to Cornwall. (academia.edu)

Classification Index

Below is the scheme most British pre-historians still use, after Richard Atkinson’s 1951 paper. The capital‐letter classes (I, II, III) describe the number and layout of entrances; the lower-case suffixes “a” and “b”, added soon afterwards by Atkinson himself and refined by later writers, flag extra ditch systems that complicate the basic plan.

Class I single formal entrance in the bank

  • Ia one entrance and two concentric ditches: the familiar inner ditch inside the bank plus a second, slighter ditch outside it. The bank thus sits between the two. Examples include Dorchester‐on-Thames Henge I and Nunwick. (deadseaquake.info)
  • Ib one entrance, an inner ditch as usual, plus a completely separate outer ditch set further away; often both ditches are picked up only as crop-marks. The unexcavated double-ring at Stapleton’s Field, Letchworth, is the type cited in field manuals. (nortoncommarch.files.wordpress.com)

Class II two diametrically opposed entrances (normally north–south)

  • IIa two entrances and a second ditch outside the bank, giving a double-ringed outline. Dorchester Henge III and the Knowlton “Church” henge are standard IIa sites. (deadseaquake.info)
  • IIb two entrances, an inner ditch inside the bank and an additional, separate outer ditch. These are exceptionally rare; a probable IIb crop-mark surrounds the double-ditched ring at Sutton Weaver, Cheshire, but no type-site has yet been excavated and published.

Class III

  • Four opposed entrances, creating quartered segments (Avebury is the textbook case). Very few monuments add more ditches, so the “a/b” subdivision is seldom used here; when it is, the rules follow those above (IIIa = extra outer ditch, IIIb = both inner and outer ditches).

Why the complication?

The entrance count was meant to capture the ceremonial choreography—single-file approach, processional through-route, or cross-movement—while the “a/b” tags alert us to monuments that went beyond the simplest bank-and-ditch recipe, perhaps to stage more elaborate gatherings or to monumentalise earlier Barrow rings. Subtypes are therefore a morphological convenience, not a chronological sequence: Ia, Ib, IIa and IIb rings can be late Neolithic or Early Bronze-Age, depending on region and associated finds.

In practice most catalogues now quote both pieces of information together—“Class IIa henge”, “Class Ib hengiform”, and so on—because the paired code instantly tells the reader (1) how many gateways were built and (2) whether one or more extra ditches complicate the circuit.

Distinguising the Henge from other Monuments

Henges were rarely isolated undertakings. Across Britain many were built into, around, or in deliberate sight-lines with other structures, forming what archaeologists now call “monument complexes” or “ritual landscapes.” Several recurring patterns show how this played out.

Henge plus circle

A first, very common pattern is the “henge-plus-circle” combination: the enclosing bank and internal ditch are laid out first, and then a ring of posts or megaliths is set inside it. Stonehenge, Avebury, the Ring of Brodgar, Stenness and Balfarg all began life as earthwork henges before gaining timber circles, stone uprights, or both. Doing so turned an already bounded arena into an architecturally articulated stage where stone or timber framed whatever ceremonies took place.

Henge with a central mound or cairn

Second is the henge with a central mound or cairn. At Catterick a low Early-Bronze-Age cobble cairn was absorbed into the henge bank; at Marden a huge chalk mound—Hatfield Barrow—rose inside the southern arc; at Mount Pleasant, Dorset, a steep inner bank ringed an earlier barrow. Such insertions let later builders anchor new rites to an older focus, creating nested layers of meaning.

Alignments

A third theme links separate monuments into longer alignments. The three Thornborough henges, Nunwick and the Devil’s Arrows standing stones fall on an almost straight north–south axis that is echoed again by Catterick and the newly recognised Moulton henge. Similar chains run through the Great Langdale valley and along the Dorset chalk. Each element kept its own ditch-inside-bank form, but the true “monument” is the line itself: people moved between nodes, not just around a single circuit.

Later reuse

Henges also attract later reuse. Roman roads slice through Catterick and King Arthur’s Round Table; early-medieval halls invade the ditch at Broomend of Crichie; Norman mottes cap the bank at Windsor Great Park. These episodes exploit the ready-made platform and the lingering prestige of a place already ancient in the builders’ eyes.

Other Monuments

Finally, many henges sit amid fields of Long Barrows, cursus avenues, pit alignments and pit-circle “post avenue” structures. Modern remote-sensing and big motorway digs—such as those along the A1 near Catterick—show that the henge was usually only the last flourish within a landscape that had been receiving ceremonial investment for centuries.

So, when archaeologists classify a site as a Class I, II or III henge, that label describes only the bank, ditch and entrances. To understand the monument in use we must look outward—to the circles, mounds, avenues, later intrusions and sight-lines that fuse individual earthworks into a much larger choreography of places, movements and memories.

Glossary

Henge — A late-Neolithic or very early Bronze-Age circular earthwork defined above all by a ditch that lies inside a surrounding bank, deliberately separating a formally bounded interior from the wider landscape. Diameters range from thirty to more than four hundred metres, and the enclosed area need not contain stones or timber rings; the defining criterion is the “ditch-inside-bank” arrangement, which distinguishes a henge from a hill-fort or cursus. Most British examples cluster in lowland England and southern Scotland and date—by radiocarbon and artefact association—to about 3100–2000 BC.

Class I Henge — A henge with a single, clearly defined entrance break. The blank circumference forces all movement into one controlled point, giving these monuments an especially theatrical approach. Good examples are King Arthur’s Round Table in Cumbria and North Mains in Strathearn. Class I rings vary widely in diameter, but typically enclose between half a hectare and two hectares.

Class II Henge — The most common type: a circular bank and internal ditch pierced by two opposed entrances, usually aligned close to the north-south axis. Thornborough South, Catterick and Stonehenge’s outer circuit all belong here. Two entrances facilitate processional movement straight through the arena and reinforce the idea that the interior was as much a route as a destination.

Class III Henge — A rarer form distinguished by four roughly equidistant gaps that divide the circuit into quadrants. The best-known instance is Avebury in Wiltshire. The quadruple portals invite cross-movement and may mark links to solstitial sunrise and sunset as well as lunar extremes, suggesting a more elaborate cosmological programme than the single- or double-entrance rings.

Hengiform Monument — A diminutive relation of the true henge, usually five to twenty metres across, with a proportionately slight bank and ditch and a single entrance gap. Because the enclosed area is small—sometimes barely large enough for two or three people—archaeologists treat hengiforms as shrines or mortuary enclosures rather than full ceremonial arenas.

Henge Enclosure (Super-henge) — An exceptionally large example, normally over three hundred metres in diameter, where the scale tips the balance toward being a monumental precinct rather than a simple ring. Durrington Walls (450 m across) and Marden (520 m) fall into this bracket. Their vast interiors contain subsidiary timber circles, pits and buildings, implying gatherings of several hundred people.

Bank-only Henge — A variant built entirely from redeposited gravel, cobbles or chalk without any encircling ditch. Mayburgh (Cumbria) and Catterick (North Yorkshire) illustrate the type. The absence of a ditch challenges neat typologies but the inner-bank idea remains intact, so most authors include these as henge derivatives.

Hengiform Classification System (Atkinson Classes) — Richard Atkinson’s 1950s framework that sorts henges primarily by the number and arrangement of entrances. Although later scholars have added qualifiers—such as “IA” for a single-entrance ring with multiple ditches—the basic three-class scheme still underpins catalogue work and distribution mapping.

Guide – Exploring the Past with LIDAR

Exploring the Past with LIDAR: A Revolutionary Tool for Archaeology

Imagine being able to see the landscape around you in a completely new way—an invisible layer revealing the hidden structures of the past, right beneath the surface. This is the power of LIDAR (Light Detection and Ranging), a technology that has revolutionized archaeology and landscape studies. In this article, we’ll take a look at how LIDAR works, where to find LIDAR data, and how to interpret it to uncover the secrets of your local landscape.

What is LIDAR?

LIDAR is a remote sensing method that uses laser light to measure distances between a sensor and the Earth’s surface. The LIDAR sensor sends out rapid pulses of laser light, and by measuring the time it takes for these pulses to bounce back, the system can create incredibly accurate three-dimensional maps of the terrain.

This technology is particularly useful in archaeology because it allows researchers to “see through” dense vegetation and other obstructions. By scanning large areas from the air (usually via a plane or drone), LIDAR can reveal ancient structures, pathways, and other features hidden beneath the canopy or soil—features that would be nearly impossible to detect with traditional methods.

How Does LIDAR Work?

The basic process of LIDAR involves the following steps:

Emission of Laser Pulses

A laser is emitted from an aircraft or drone, directed towards the ground below.

Data Collection

The laser pulses bounce off the surface and return to the sensor. By measuring the time it takes for each pulse to return, LIDAR systems can calculate the distance between the sensor and the surface below.

Data Processing

The return time for each pulse is converted into highly detailed 3D point clouds, which represent the topography of the area. These point clouds can then be used to generate highly accurate digital elevation models (DEMs) or surface models.

Analysis and Visualization

These models can be further processed to reveal features like ancient structures, roads, and Earthworks, offering archaeologists and researchers a clearer picture of past human activity.

Where Can You Access LIDAR Maps?

LIDAR data is often collected by government agencies, research institutions, and private companies. Thankfully, several free LIDAR mapping services allow public access to this valuable data. Below are a couple of resources where you can explore LIDAR data for your own area:

UK LIDAR Data Service (UK LIDAR Data)

Managed by the UK Environment Agency, this service provides free access to high-resolution LIDAR data for England, Wales, and Northern Ireland. It allows users to view and download data in various formats, which can be helpful for understanding the terrain and identifying archaeological sites.

OpenTopography (OpenTopography)

OpenTopography is an international platform that offers free access to LIDAR datasets from across the globe, including many archaeological regions. The site provides downloadable data for creating DEMs and other visual models, enabling users to view topography in more detail.

Differences Between the Services

Both of these LIDAR mapping services offer free access to LIDAR data, but there are a few differences to consider:

Coverage Area

The UK LIDAR Data Service focuses specifically on the UK, while OpenTopography offers datasets from various countries around the world. If you’re interested in a global scope or specific international sites, OpenTopography might be your best choice.

Data Access and Usability

UK LIDAR allows for direct access to high-resolution data files that can be easily imported into GIS software, while OpenTopography offers a user-friendly interface for visualizing the data before downloading. If you’re new to LIDAR mapping, OpenTopography’s interactive map can be a great way to explore the data visually before downloading raw datasets.

Maximum Depth of Petentration and Accuracy

The maximum theoretical depth of LiDAR (Light Detection and Ranging) can vary based on the specific type of LiDAR technology being used, particularly when it comes to bathymetric LiDAR, which is designed to measure underwater depths. Here are some key points regarding the maximum depths achievable with LiDAR:

General Depth Range

LiDAR can typically measure depths from about 0.9 to 40 meters (approximately 3 to 131 feet) in water. The exact depth can depend on water clarity and the specific LiDAR system used.

Bathymetric LiDAR

Bathymetric LiDAR systems are specifically designed for underwater measurements and can achieve maximum depths of around 2.84 meters (approximately 9.3 feet) in certain conditions, such as at the edge of a pool or in clear water.

Theoretical Models

Some theoretical models suggest that satellite photon-counting LiDAR can analyze maximum bathymetric depths, but these models are often complex and depend on various environmental factors.

Vertical Accuracy

The vertical accuracy of LiDAR measurements in water is generally around 15 centimeters (about 6 inches), which is crucial for applications requiring precise depth measurements.

In summary, while the maximum theoretical depth of LiDAR can reach up to 40 meters in ideal conditions, practical applications often see effective measurements in the range of 0.9 to 2.84 meters depending on the technology and environmental factors.

How to View Your Own Area on LIDAR

Now that you have access to LIDAR data, you can start exploring your local area. To get started:

Visit the LIDAR Service Website

Go to either the UK LIDAR Data Service or OpenTopography, depending on your region.

Search for Your LocationEnter the location you’re interested in (e.g., your town, village, or any region of archaeological interest) into the search bar or use the map interface to navigate to your area.

Select Data Layers

Many platforms will allow you to overlay different layers, such as terrain models or vegetation indices. You can often choose between raw elevation data or more processed versions, such as shaded relief maps, which can help bring the features of the landscape to life.

Explore the Data

Once you’ve located your area, zoom in and start examining the terrain. You might begin to notice subtle features—like circular depressions, straight lines, or embankments—that could be clues to ancient settlements, roadways, or other archaeological features. These features are often hidden to the naked eye but come to life in the LIDAR data.

How to Interpret What You’re Seeing

Interpreting LIDAR data requires a bit of practice, but here are some general tips for reading the maps:

Elevation Models

Digital Elevation Models (DEMs) can show the height of the terrain. Areas that are more elevated, such as hills or mounds, may indicate the presence of ancient structures, burial mounds, or defensive earthworks.

Point Clouds: The point cloud representation shows the distribution of laser points on the surface. Look for patterns in the density and clustering of points, which may hint at man-made features. For example, straight lines may indicate roads, walls, or boundary markers.

Shaded Relief Maps

These maps provide a more visually accessible way to view the landscape’s features. Shadows are used to accentuate changes in elevation, making it easier to spot features such as ditches, mounds, or roads that may have been built by past societies.

Encouraging Your Own Adventure

By using LIDAR, you’re not just looking at a map—you’re uncovering a hidden world that’s waiting to be discovered. It’s like stepping into the shoes of an archaeologist or explorer, finding clues to our shared history right in your own backyard. Even if the terrain seems unremarkable at first glance, LIDAR can reveal the subtle traces of human activity that lie just beneath the surface.

So, grab your binoculars, explore the hidden topography of your area, and let the journey of discovery begin. Who knows what ancient roads, forgotten ruins, or hidden villages might be waiting to be uncovered?

Professional LIDAR Services: Unlocking Precise 3D Mapping

While free LIDAR mapping services provide a fantastic entry point for exploring the landscape, professional LIDAR services offer higher-resolution data, more advanced processing capabilities, and tailored solutions for complex archaeological or geographical projects. These services are often used by research institutions, governments, engineering firms, and private companies to gather highly accurate data over large areas. Professional LIDAR services also allow for more precise interpretation of the data, particularly in environments that require specialized expertise.

How Professional LIDAR Services Work

Professional LIDAR services typically involve the following process:

Data Collection

Professional LIDAR data is typically collected by aircraft or drones equipped with LIDAR sensors. These sensors emit laser pulses and record the time it takes for them to return, measuring the distance to the ground below. Data is collected for both the surface and vegetation layers, allowing for detailed topographic mapping.

Point Cloud Processing

After data collection, the LIDAR point clouds (3D data points) are processed and cleaned to create digital elevation models (DEMs), which can then be used to generate 3D models of the terrain. These models can include both visible and subsurface features, depending on the capabilities of the LIDAR system used.

Customized Data Output

Professional services often offer more advanced post-processing and analysis options, including tailored visualizations, contour maps, and 3D terrain models, specifically designed for archaeological, environmental, or engineering needs.

Project-Specific Analysis

With professional LIDAR services, you can get more accurate and detailed analysis, such as feature identification, vegetation analysis, or flood risk assessment. In archaeology, this can mean uncovering subtle earthworks, hidden structures, or ancient pathways that would be otherwise invisible to the naked eye.

Popular Professional LIDAR Services

Here’s a list of resources and services that provide professional LIDAR data and technology. These services are often tailored to specific industries, and they typically require purchasing or contracting services for data collection and analysis:

Riegl LIDAR (Riegl LIDAR)

Riegl is a leader in the field of professional LIDAR systems and sensors. They offer a wide range of LIDAR solutions for terrestrial, airborne, and mobile mapping applications. Their systems are used in topographic surveys, archaeology, forestry, and environmental studies.

Leica Geosystems (Leica Geosystems)

Leica offers a broad range of professional LIDAR systems and services. They specialize in high-precision, 3D data collection for industries such as construction, mining, and archaeology. Leica provides both hardware for LIDAR collection and software tools for data processing and analysis.

Optech (Teledyne) (Optech)

Optech, now part of Teledyne, provides advanced LIDAR systems for airborne and terrestrial mapping. Their products are used for applications ranging from archaeology and forestry to floodplain mapping and environmental monitoring.

Topcon Positioning Systems (Topcon Positioning Systems)

Topcon offers LIDAR systems that are suitable for a wide range of mapping projects, including those in the civil engineering and infrastructure sectors. Their solutions include airborne, mobile, and ground-based LIDAR systems.

Surdex Corporation (Surdex)

Surdex provides professional LIDAR mapping services, offering high-resolution data collection for industries such as mining, forestry, and land development. They provide both LIDAR data collection and processing services tailored to their clients’ needs.

Quantum Spatial (Quantum Spatial)

A provider of geospatial solutions, Quantum Spatial specializes in high-accuracy LIDAR data collection and analysis for government agencies, environmental monitoring, and infrastructure planning. They are known for their expertise in applying LIDAR technology to large-scale mapping projects.

Aerometric (Aerometric)

Aerometric provides airborne LIDAR data collection services for the environmental and natural resource sectors. They specialize in topographic and bathymetric LIDAR services, offering detailed mapping solutions.

3D Laser Mapping (3D Laser Mapping)

3D Laser Mapping offers both hardware and software solutions for LIDAR applications. They specialize in providing highly accurate data for mining, construction, archaeology, and urban planning projects.

Further Information and Resources

LIDAR 101: Introduction and Applications – An introductory guide on how LIDAR works, its applications, and industries that use it. 

LiDAR Technology Overview from NASA – A detailed explanation of LIDAR technology, how it’s used in Earth sciences, and its contributions to environmental monitoring. Explore here

The LIDAR Magazine – A publication dedicated to LIDAR news, technologies, and trends in the geospatial industry. Visit here

LIDAR News – Another valuable resource for LIDAR news, case studies, and technology developments. Visit here

LIDAR is a powerful tool, and with these resources, you can explore how professional services can be used to create high-precision maps and models for your specific needs. Whether you’re involved in archaeology, environmental studies, or simply interested in understanding the landscape in new ways, these professional LIDAR services can unlock a wealth of information hidden beneath the surface.

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