Thirty Years of CAU Archaeology Going Nowhere?

September 19, 2026 Trebor2510

Langdon Takes Six Hours to See the Bigger Picture: Long Holme Drove, Car Dyke and the Post-Glacial Flooding Hypothesis

For almost thirty years, archaeologists from the Cambridge Archaeological Unit have been excavating the extraordinary prehistoric landscape around Over and Needingworth in Cambridgeshire. (Long Holme Drove, Car Dyke and the Post-Glacial Flooding Hypothesis – CAU archaeology)

They have uncovered Neolithic occupation, Bronze Age barrows, field systems, deep pits, wooden ladders, palaeochannels, fish traps, worked timber, a fragment of a log boat, evidence of flooding, and later Roman activity.

The amount of detail is enormous.

Yet after decades of investigation, one basic question appears to have received remarkably little attention:

How did all these individual features work together as a landscape?

That was the question I asked when I began comparing the CAU excavation reports with my existing research into the Car Dyke and the Post-Glacial Flooding Hypothesis.

Within about six hours, a very different picture began to emerge.

The excavation lies beside Long Holme Drove, an unusual linear feature which survives on historic mapping and LiDAR as what appears to be a substantial bank-and-ditch or dyke-like corridor. Follow that feature northwards and it heads towards the River Great Ouse at Hermitage — exactly where my earlier Car Dyke research identifies the continuation of the old Car Dyke route.

At the same time, CAU’s own environmental evidence shows that prehistoric palaeochannels here remained wet, water-filled and economically important for thousands of years.

Taken together, these discoveries do not merely add another archaeological site to the map.

They may provide one of the strongest independent pieces of evidence yet for two ideas I have been arguing for years:

that parts of the Car Dyke landscape have prehistoric origins, and that post-glacial Britain remained far wetter for far longer than conventional reconstructions generally suggest.

(Long Holme Drove, Car Dyke and the Post-Glacial Flooding Hypothesis - CAU archaeology) — (Long Holme Drove, Car Dyke and the Post-Glacial Flooding Hypothesis – CAU archaeology)

Nearly Thirty Years of Excavation

The Over/Needingworth project began in the mid-1990s and has developed into one of the most extensive archaeological investigations of a prehistoric landscape in eastern England.

The 2020–21 Phase V.1 excavation alone covered 12.64 hectares, and the report describes it as merely the latest stage of a long-running archaeological programme extending back to the mid-1990s.

What has been uncovered is genuinely impressive.

The site produced evidence ranging from the Mesolithic through to the Roman period, with major phases of occupation during the Neolithic and Bronze Age.

The problem is not the excavation.

The problem is interpretation.

The evidence has largely been divided into familiar archaeological boxes:

barrows, fields, droveways, watering holes, palaeochannels, fish weirs and Roman activity.

But landscapes do not operate in archaeological boxes.

People need raw materials.

They need water.

They need transport.

They need routes between resources and settlements.

And once those questions are asked, the Over landscape starts looking very different.

A Resource Landscape, Not Just a Farming Landscape

The geology is fundamental.

The site lies on low terraces composed of clay, silt, sand, gravel and peat, dissected by former channels of the Great Ouse.

That means the prehistoric inhabitants had immediate access to:

gravel,
usable stone,
flint nodules,
clay,
timber,
groundwater,
rivers and palaeochannels.

The excavation reports themselves demonstrate that these resources were being deliberately exploited.

The flint specialist identified locally available flint derived from gravel cobbles and nodules, alongside higher-quality imported chalk flint.

The burnt-stone specialist concluded that prehistoric people were selectively collecting sandstone from the local gravels because its properties made it particularly suitable for heating liquids and related activities.

And Barrow 20 provides direct evidence that prehistoric people excavated gravel and deliberately reused it: material dug from the ring ditch was used to enlarge the barrow mound.

So there is no question that the gravels themselves were a resource.

That becomes important when we look at the strange pits scattered across the excavation.

The “Watering Holes” That May Not Have Been Watering Holes

CAU repeatedly describes a class of substantial prehistoric pits as:

pit-wells or watering holes.

Some contained wooden ladders.

Some intersected groundwater.

Some contained waterlogged deposits.

At first sight the interpretation sounds reasonable.

Until the specialist reports are read carefully.

The geoarchaeologist actually says:

“The exact purpose of these isolated features is unclear.”

The same discussion records a standing water table at their bottoms and notes their association with wooden access structures.

That distinction is critical.

The evidence demonstrates:

people dug pits + people descended into them + groundwater occurred at their bottoms.

It does not automatically demonstrate:

people dug them because they wanted water.

Four separate pits contained log ladders.

One of those pits, F.1199, was only about a metre deep.

Why install a ladder into a one-metre hole?

Possibly because its sides were steep and unstable.

Possibly because people repeatedly needed to work at its bottom.

That is equally compatible with extraction or maintenance as it is with drawing water.

And then there is F.792.

Despite being classified with the watering-hole/pit-well group, the environmental specialist states:

“There is little evidence to suggest that pit F.792 contained water.”

That single observation should make us extremely cautious about treating the phrase “watering hole” as established fact.

Were Some of These Actually Extraction Pits?

Once the geology is considered, another possibility appears.

The landscape contains useful gravel.

The inhabitants demonstrably collected stone from that gravel.

They demonstrably used local flint nodules.

What happens if a prehistoric community starts excavating a broad pit into a gravel terrace?

At first the gravel is dry.

As the pit becomes deeper, access becomes increasingly difficult.

A ladder or wooden step is installed.

Eventually the excavation reaches the groundwater table.

Water begins entering the pit.

Sand and gravel walls become unstable.

The excavation is abandoned or repurposed.

The former extraction pit now becomes a perfectly serviceable source of water.

That sequence would explain several otherwise disconnected observations.

And one particular feature provides an excellent case study.

F.691 — A Two-Metre Deep Neolithic Mystery

F.691 dates to the Late Neolithic.

It measured approximately 3.7 metres by 3.25 metres and 2.05 metres deep.

Its lower deposits were waterlogged.

Above those were deposits of slumped sand and gravel.

A timber driven into the side of the pit may have functioned as a step, while another forked timber has been compared with wooden devices associated with drawing containers from wells.

The basal timber has been radiocarbon dated to 2885–2670 BC.

F.691 also produced the largest individual assemblage of worked flint from the excavation.

But this is where caution is necessary.

A substantial proportion of that flint was high-quality imported chalk flint rather than simply material extracted from the local gravel.

So F.691 cannot presently be called a proven flint quarry.

What it does demonstrate is that people were repeatedly accessing the bottom of a substantial Late Neolithic excavation cut into unstable sand and gravel, which subsequently became waterlogged.

Its original purpose remains unresolved.

And that is the point.

Picture5 2 — (Long Holme Drove, Car Dyke and the Post-Glacial Flooding Hypothesis – CAU archaeology)

The Real Story May Be Beneath the Palaeochannels

The palaeochannel evidence is even more important.

This is where the excavation begins to intersect directly with the Post-Glacial Flooding Hypothesis.

CAU’s geoarchaeological work reconstructs a former multichannel Great Ouse system.

Around 13,300 years BP, Channels I and VIII formed part of a high-energy floodplain system, with cross-bedded river deposits and gravel bars.

The report then argues that the main multichannel system declined during the transition into the Holocene.

But what happens next is crucial.

The channels did not simply become dry land.

The report says that wood peat developed in the abandoned channels wherever the permanent water table remained high.

In other words:

“abandoned river channel” did not mean “dry channel”.

That difference is fundamental.

Picture6 2 — (Long Holme Drove, Car Dyke and the Post-Glacial Flooding Hypothesis – CAU archaeology)

Water in the Early Mesolithic

Channel I contains pollen and sedimentary evidence attributed to the early Holocene.

The lower pollen samples are considered to date from the Early Mesolithic, before around 10,000 cal BP.

The sequence alternates between:

fluvial sands,
sandy silts,
organic deposits,
and peat.

The specialist interprets this as repeated changes between higher-energy water movement and slower-water conditions.

That is not evidence of a completely dry floodplain.

It is evidence of a landscape in which water continued to play an active role.

Deep Open Water Around 5500 BC?

Channel VIII may be even more significant.

Its pollen assemblage was tentatively placed around 7500 cal BP, approximately 5550 BC, although the specialist allows a broader Late Mesolithic to mid-Neolithic range.

The important part is not merely the date.

It is the ecology.

The report identifies:

broad-leaved pondweed,
water milfoil,
yellow water lily,
reeds,
sedges,
wet alder and willow woodland.

And the specialist writes that the aquatic plants:

“certainly indicate deeper open water.”

That is extremely important.

Because this channel was supposedly no longer one of the principal flowing courses of the Great Ouse.

Yet thousands of years into the Holocene it could still contain substantial open water.

That is exactly the type of landscape predicted by the Post-Glacial Flooding Hypothesis.

The Water Even Returned

Channel I later underwent another major hydrological change.

After peat had developed, a powerful erosional event cut through the deposits and water flow resumed.

The report describes this as:

“definitive evidence that water flow restarted in the channel.”

CAU prefers tidal action and marine transgression as the explanation.

But even the report admits that the violence of the initial erosional event is difficult to explain solely through rising sea level.

That matters.

Because the archaeological fact is:

the channel became active again.

The cause is interpretation.

By the Bronze Age They Were Using Boats

By the Middle Bronze Age, this was unquestionably an actively exploited water landscape.

A wood horizon associated with Channel I has been radiocarbon dated to:

1628–1502 BC.

The excavation recovered:

large concentrations of worked timber,
successive probable fish weirs,
wooden piles,
possible bridging structures,
woodworking debris,
a wooden bowl,
and part of a log boat.

That changes the entire interpretation of the landscape.

These people were not merely living beside wet ground.

They were using the waterways.

And if boats were operating through these channels, we must ask the obvious question:

what were they transporting?

Gravel, Flint, Timber — and Transport

Now the pieces begin to connect.

The landscape supplied raw materials.

People excavated gravel.

They selected useful stone.

They had local flint.

They worked timber.

They occupied the channel edges.

They had boats.

They constructed fish weirs and probable riverside structures.

So why would transport not be part of the system?

Yet transport is rarely placed at the centre of the interpretation.

Instead we get isolated labels:

pit.

watering hole.

field boundary.

fish trap.

palaeochannel.

The bigger economic question is largely missing.

And Then There Is Long Holme Drove

This is where LiDAR becomes critical.

Long Holme Drove survives on historic mapping as a curious linear route running through the quarry landscape.

Large sections have now disappeared beneath modern gravel extraction.

But the surviving LiDAR shows something much more substantial than an ordinary farm road.

The road appears to occupy the crest or edge of a broad banked linear earthwork with an adjacent depression or ditch.

It looks far more like:

an older dyke or embanked water-management feature later reused as a road.

LiDAR cannot date it.

But it can preserve morphology after physical destruction.

And when the feature is followed northward, it heads toward the River Great Ouse at Hermitage.

That matters because my previous Car Dyke research had already identified the old Car Dyke route at precisely this point.

Suddenly we have a possible physical chain:

prehistoric resource landscape
→ Long Holme Drove dyke-like corridor
→ Great Ouse at Hermitage
→ Car Dyke.

That is potentially a very significant discovery.

Did CAU Excavate Long Holme Drove?

The obvious question was whether the archaeologists had already sectioned it.

The 2019 CAU excavation actually straddled Long Holme Drove.

But when the excavation plans are examined, the drove itself appears largely to survive as an unexcavated strip between stripped archaeological areas.

The report even refers to archaeological features disappearing into an:

“unexcavated/truncated area beneath a former farm track.”

I have found no published section through Long Holme Drove itself in the available report.

No bank profile.

No road-construction sequence.

No underlying palaeosol date.

No archaeological dating of the earthwork.

This is extraordinary because the modern quarry has subsequently removed parts of that landscape.

The feature may now physically be gone.

They Found a Bronze Age Droveway — But It Is Not Long Holme Drove

CAU did discover a genuine prehistoric droveway.

The Phase V.1 excavation exposed two parallel ditch lines forming a Middle Bronze Age route extending across the site.

The ditches lay around 4.5–6.9 metres apart, and the route was traced northwest toward the 2019 excavation area.

But the excavation plans show that this Bronze Age droveway follows a different alignment from Long Holme Drove.

That makes the latter more intriguing.

Long Holme Drove cannot simply be dismissed as the Bronze Age droveway CAU already identified.

It is another feature altogether.

Thirty Years of Archaeology — But No Landscape Connection?

This is where the criticism must be made.

CAU has produced an extraordinary archaeological archive.

Nobody can reasonably deny the quality or quantity of the excavation.

But after almost thirty years, the project has generated enormous detail while seemingly failing to explore one of the most obvious landscape-scale questions:

Could these waterways, resource zones, droveways and linear earthworks have formed an integrated transport system?

Within only a few hours of comparing the excavation reports with historic mapping, LiDAR and my existing Car Dyke reconstruction, a potentially important relationship emerged.

That does not mean the relationship is proven.

It means it should have been tested.

And apparently it has not been.

Archaeological Gatekeeping and the Verification Problem

There is another problem.

The later Phase V2 report — CAU Report 1563 — may contain precisely the information needed to determine what happened when the now-destroyed Long Holme Drove corridor was removed.

But unlike several earlier reports, it is not readily accessible in the same public archive.

That does not prove deliberate suppression.

But it does demonstrate a serious problem with archaeological transparency.

Archaeology depends upon verification.

If a physical feature is destroyed by quarrying and the resulting excavation records are difficult for outside researchers to access, independent testing becomes unnecessarily difficult.

Fortunately, LiDAR preserves a record of the feature before its destruction.

That is one reason landscape archaeology can no longer rely solely upon conventional excavation reports.

What This Means for the Post-Glacial Flooding Hypothesis

The Over evidence does not prove every mechanism proposed by the PGFH.

But it independently verifies several of its central predictions.

The excavation demonstrates:

persistent high groundwater in former river channels;
peat formation under a permanent water table;
Early Holocene fluvial activity;
potentially deep open water around 5500 BC;
prehistoric occupation immediately beside those wet channels;
renewed later water flow;
Bronze Age boats and fishing structures;
subsequent inundation and fen development.

Most importantly, it shows that a palaeochannel could cease being the principal river course while remaining a substantial body of water for thousands of years.

That is exactly the distinction I have repeatedly argued conventional archaeology overlooks.

The PGFH does not require every old river channel to remain a powerful flowing river.

It requires a landscape in which groundwater and residual surface water remained much higher and more extensive than modern conditions suggest.

That is precisely what the environmental evidence at Over demonstrates.

What This Means for Car Dyke

My Car Dyke research has long argued that parts of the system predate the Romans.

The conventional attribution of Car Dyke to Roman engineering rests heavily on Roman-period reuse and finds rather than universally secure construction dates.

Over/Needingworth gives us something important.

Long before the Romans:

prehistoric communities were exploiting these waterways;
boats were present;
fish-weirs and timber structures were being constructed;
raw materials were being extracted;
large routeways existed;
and the palaeochannel landscape was economically active.

The LiDAR now suggests that Long Holme Drove may represent a surviving dyke-like route running from that resource zone toward the Car Dyke corridor at Hermitage.

That does not yet directly date Long Holme Drove.

But it does make the idea of a prehistoric transport network later inherited or modified by Roman engineers substantially more plausible.

The question is no longer:

“Did the Romans know how to dig canals?”

Of course they did.

The real question is:

“How much of the system was already there?”

The Critical Test

The hypothesis can be tested.

We need:

1. The Phase V2 excavation archive.
Did the later quarry excavation physically cross the missing Long Holme Drove corridor?

2. A section through the drove.
Does the road surface sit above an earlier bank or ditch?

3. Radiocarbon dating.
Is datable organic material sealed beneath or within that bank?

4. GIS alignment.
Does the dyke-like earthwork physically connect with the Ouse/Hermitage Car Dyke route?

5. Sediment analysis.
Does the ditch contain aquatic or wetland sedimentation consistent with a former watercourse?

Those tests could establish whether the LiDAR observation represents a prehistoric dyke, a later drainage feature, or something else.

Thirty Years of Pieces — Six Hours to See the Pattern

For almost thirty years CAU has excavated one of Britain’s most extraordinary prehistoric landscapes.

They found the pieces.

Neolithic occupation.

Bronze Age fields.

Deep pits with ladders.

Gravel exploitation.

Palaeochannels.

Fish traps.

Wooden structures.

A log boat.

Flooding.

Roman channel activity.

But the wider relationship between those discoveries appears to have remained largely unexplored.

Looking at the evidence through the combined lens of the Post-Glacial Flooding Hypothesis, Car Dyke research, historic mapping and LiDAR produces a different picture.

This may not simply have been a sequence of unrelated archaeological sites.

It may have been a long-lived resource and transport landscape organised around water.

Long Holme Drove may preserve the missing physical link between that prehistoric landscape and the Car Dyke corridor.

And CAU’s own environmental evidence independently confirms something fundamental to the PGFH:

former river channels remained wet, waterlogged and in some cases substantially open-water environments for thousands of years into the Holocene.

That does not finish the argument.

But it changes it.

After nearly thirty years of excavation, perhaps the most important discovery was not another pit, another barrow or another ditch.

It was recognising that they may all belong to the same landscape.

The question now is not simply whether Rome built Car Dyke.

It is how much of Car Dyke Rome inherited.

PODCAST

Author’s Biography

Robert John Langdon, a polymathic luminary, emerges as a writer, historian, and eminent specialist in LiDAR Landscape Archaeology.

His intellectual voyage has been interwoven with stints as an astute scrutineer in government and grand corporate bastions, a tapestry spanning British Telecommunications, Cable and Wireless, British Gas, and the esteemed University of London.

A decade hence, Robert’s transition into retirement unfurled a chapter of insatiable curiosity. This phase saw him immerse himself in Politics, Archaeology, Philosophy, and the enigmatic realm of Quantum Mechanics. His academic odyssey traversed the venerable corridors of knowledge hubs such as the Museum of London, University College London, Birkbeck College, The City Literature Institute, and Chichester University.

In the symphony of his life, Robert is a custodian of three progeny and a pair of cherished grandchildren. His sanctuary lies ensconced in the embrace of West Wales, where he inhabits an isolated cottage, its windows framing a vista of the boundless sea – a retreat from the scrutinising gaze of Her Majesty’s Revenue and Customs, an amiable clandestinity in the lap of nature.

Exploring Prehistoric Britain: A Journey Through Time

My blog delves into the fascinating mysteries of prehistoric Britain, challenging conventional narratives and offering fresh perspectives grounded in cutting-edge research, particularly LiDAR technology. I invite you to explore some key areas of my research. For example, the Wansdyke, often cited as a defensive structure, is re-examined in light of new evidence. I’ve presented my findings in my blog post Wansdyke: A British Frontier Wall – ‘Debunked’, and a Wansdyke LiDAR Flyover video further visualises my conclusions.

My work also often challenges established archaeological dogma. I argue that many sites, such as Hambledon Hill, commonly identified as Iron Age hillforts, are not what they seem. My posts Lidar Investigation Hambledon Hill – NOT an ‘Iron Age Fort’ and Unmasking the “Iron Age Hillfort” Myth explore these ideas in detail and offer an alternative view. Similarly, sites like Cissbury Ring and White Sheet Camp receive re-evaluations based on LiDAR analysis in my posts “Lidar Investigation Cissbury Ring through time” and “Lidar Investigation White Sheet Camp,“ revealing fascinating insights into their true purpose. I have also examined South Cadbury Castle, often linked to the mythical Camelot56.

My research also extends to ancient water management, including the role of canals and other linear earthworks. I have discussed the true origins of Car Dyke in multiple posts, including Car Dyke – ABC News Podcast and Lidar Investigation Car Dyke – North Section, which suggest a Mesolithic origin 2357. I also explore the misidentification of Roman aqueducts, as seen in my posts on the Great Chesters (Roman) Aqueduct. My research has also been greatly informed by my post-glacial flooding hypothesis, which has helped explain landscape transformations over time. I have discussed this hypothesis in several posts, including AI now supports my Post-Glacial Flooding Hypothesis and Exploring Britain’s Flooded Past: A Personal Journey

Finally, my blog also investigates prehistoric burial practices, as seen in Prehistoric Burial Practices of Britain and explores the mystery of Pillow Mounds, often mistaken for medieval rabbit warrens, but with a potential link to Bronze Age cremation in my posts: Pillow Mounds: A Bronze Age Legacy of Cremation? and The Mystery of Pillow Mounds: Are They Really Medieval Rabbit Warrens?. My research also includes astronomical insights into ancient sites, for example, in Rediscovering the Winter Solstice: The Original Winter Festival. I also review new information about the construction of Stonehenge in The Stonehenge Enigma.

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