Crowdy Reservoir – Traces of Mesolithic Cornwall


In the shadow of Rough Tor is an area of Bodmin Moor known as Crowdy Marsh. Today it is the site of a large reservoir but in the 19th century this was considered a dangerous place, an evil morass that trapped ponies, cattle and men on horseback. The writer J. W Malin called it ” a sinister-looking, desolate part of the moor.” Many thousands of years before this however, from around the end of the last Ice Age, this place was a home, or at least a stopping place, for Mesolithic people. Crowdy Reservoir hides traces of the first period of human occupation in Cornwall some 10,000 years ago.

The Water Works

For hundreds of years Crowdy Marsh was just a large area of low-lying bog where the run-off water from the surrounding moorland gathered and fed a powerful tributary of the River Camel. But in the 20th century it was decided that this natural resource should be captured.

Crowdy Reservoir became one part of a large water works scheme that was first implemented in 1925 and expanded and improved over the decades that followed. Since the ‘new’ dam was built in 1973 the lake has grown to cover 115 acres and helps supply much of North Cornwall with water.

But, in the same way that the action of the water at the reservoir at Stithians exposed secrets that had lain undiscovered for centuries, Crowdy has become a site of archaeological importance due to what the lapping waves have revealed.

Microliths & the Mesolithic Moor

The landscape that we see on the moor today is quite different from what our ancestors would have experienced. As the temperatures rose at the end of the last Ice Age, around 11,000 years ago, so did the sea levels. It is thought that the small groups of hunter-gathers roaming Cornwall would have found Bodmin Moor a heathland surrounded by birch woodland.

Crowdy from Showery Tor

Over the next thousand years or so, before the introduction of agriculture, this exposed upland would gradually become more and more forested, though the highest tors would still have remained bare. As the sea levels continued to gradually rise the land-bridge with the rest of Europe was submerging, cutting off what was to become the British Isles, and interestingly many of the rivers that we know today would have been navigable far deeper in land.

“From the air it might have looked as though the moor, decked in an emerald crescent of lowland forest, was anchored in the swirling waters by glistening threads . . . men could have watched the high tide flood the rivers further inland than at present . . .”

Pat Munn, Bodmin Moor, 1972

The area around Crowdy Marsh, which may have been a lake at the time, is thought to have been wooded too.

There are just a handful of known sites in Cornwall that have been positively linked to the Mesolithic – that is life in Cornwall 6000 to 10,000 years ago – but it is thought that many hundreds more probably exist but are as yet undiscovered.

These sites would have been the places that the Mesolithic people, our earliest ancestors, set up seasonal camps or where they rested and passed the time making tools or weapons, perhaps where they regularly sheltered during a hunting trip, paused to butcher their kill and eat, or where they cleaned and prepared animal skins.

Perhaps the most famous Mesolithic site on Bodmin Moor is Dozmary Pool where literally hundreds of flint microliths, that is small points made for arrows, knives and tools, have been uncovered by the action of the water. But it is not so widely known that a large number of microliths have also been found at Crowdy.

Cornwall Archaeology, No 16, 1977 – Peter Trudgian, Excavation of a Cairn at Crowdy Marsh, Advent

Most of the accoutrements of a hunter-gather lifestyle – skins for clothes, bone and wood for tools and ornaments, plant fibres for rope, were made of perishable materials and therefore have not survived. It is stone tools, tiny worked flakes of flint and flint cores that are really our only tangible link to them. These chips of stone left scattered on a long buried land surface the only sign that they were ever there. And this is what you find at Crowdy Reservoir.

“The eroded areas around both Crowdy Marsh and Siblyback reservoirs have been known for some years to produce relatively large quantities of Mesolithic flint.”

The Mesolithic Period in Cornwall, Peter Berridge & Alison Roberts, Cornwall Archaeology, No 25, 1986

Finding Flint

There are no natural sources of flint in Cornwall so along with ‘importing’ flint from upcountry it is thought that our ancestors would also have brought flint pebbles from the north coast where they were (and still are) washed up on the beach. Amazingly these stones, such a precious resource for our ancestors, wash up on the Cornish coast from an ancient off-shore chalk deposit called the Haig Fras Cretaceous deposit which lies about 100 miles out to sea, slightly north west of Lands End.

It was the archaeologist Peter Trudgian who first identified numerous Mesolithic flints at Crowdy, which he picked up on the foreshore of the lake in 1970. He found pockets of flint at several sites on the water’s edge and some spots where the finds were just sticking up out of the marshy ground. These included scrapers, blades and many flint flakes.

At one location on the south side of Crowdy Trudgian discovered an end scraper, a burnt scraper, one broken blade and 29 flakes all dated to between 8000BC and 4000BC. He concluded that, with the exception of a small collection of flakes that he found several hundred metres from the marsh (which were black flint, perhaps from Beer in Dorset), all the other flint finds were ‘beach flint’. That is stones that the Mesolithic people had gathered and brought from the coast to put to various uses.

  • I tested this idea of an offshore deposit myself and was surprised that in just a few minutes at Sandymouth I had picked up three pieces of rounded flint that must have been washed ashore.
Beach flint from Cornwall’s north coast

“Most of the Mesolithic flint and chert assemblages from Cornwall appear to be derived from beach pebbles identical to those found today along the coastline.”

The Mesolithic Period in Cornwall, Peter Berridge & Alison Roberts, 1986

The Mysterious Cairn

One of the most obvious features as you arrive at Crowdy is the distinctive hump in the landscape close to the modern weir. This is a Bronze Age barrow, known as Lowermoor barrow, which is about 19m in diameter and nearly 3m high. This monument would have built a few thousand years after their Mesolithic ancestors had been dropping flint everywhere. It was first recorded in 1907 and scheduled in 1956.

There is a second barrow out of sight in an adjacent field and many more on the nearby Davidstow Moor and towards Showery Tor and Rough Tor. These all add to the atmosphere of the site, the feeling of antiquity, but another now barely visible monument deserves just as much attention.


During an expansion of the reservoir in the 1970s a fascinating excavation was carried out, the subsequent report makes puzzling reading. A new dam, the one we see today I believe, was being built a little downriver from the original which, according to the archaeologist Peter Trudgian, had been constructed where three ancient trackways merged at a ford.

Trudgian’s study focused on a small cairn nearby which had been identified in earlier fieldwork and his report suggests that this unprepossessing mound may be far older than anyone suspected.

Plan of the cairn from Peter Trudgian’s report, Cornwall Archaeology No 16, 1977

The cairn was small and flat-topped, built “with care” overlooking what would have been Crowdy Marsh. About 10m in diameter when the undergrowth was removed a circular pile of stones was revealed, placed directly on to the old land surface. Most of the stones were fist-sized pieces of moorland granite, probably collected from the surrounding area, and carefully arranged. But it was what Trudgian found on and around the cairn which was most surprising.

Simply put Trudgian’s excavation identified some 63 Mesolithic flints scattered in the soil around and on top of this cairn but none beneath it. Suggesting that the cairn was Mesolithic in date or older . . . Which would be VERY unusual.

Some 64 struck flints were found in total, one was identified as an Early Bronze Age barbed arrowhead, while the other 63 were all typical of a Mesolithic assemblage. All were made from beach pebbles.


I was very intrigued by this idea of a Mesolithic monument and after a lot of head scratching decided that the best course of action was to ask an expert what they thought of this discovery. I contacted the wonderful Peter Herring, an archaeologist and Historic England’s Head of Historic Place Investigation for the South West.

Here is his reply which I think throws some light on the problem:

“I’ve had another look at the Peter Trudgian article, for the first time in many years!

It’s a careful piece where he makes several good observations and tentatively suggests interpretations. It’s probably fair to say that he was kite-flying when he suggested that the cairn may have been Mesolithic, but the lack of flints beneath it is indeed interesting, and it is that which needs consideration here. We may presume that he excavated the earth there very carefully – he was a meticulous man, as the paper indicates – so it’s safe to say there really were no flints there.

My own interpretation would make more of the fact that the soil on top of the cairn did contain flints, which would be unexpected if the land had indeed never been ploughed, as Peter suggests, again reasonably. The Mesolithic flints in the soil around the cairn would be regarded as residual, and to get into the soil overlying the cairn would have needed to be placed there, along with the soil. I would suggest then that the cairn builders may have stripped their area of much (but not all) of its soil prior to construction (Peter recognised the ‘black old land surface’ with difficulty, leading me to think that much of the earth had indeed been temporarily removed) and then used that later to create the earthy covering. It could therefore be another cairn of the Early Bronze Age, with the barbed and tanged arrowhead of some interest.”

So, Peter Herring suggests that the Mesolithic flints came to be on and around the cairn when its Early Bronze Age builders prepared the area for construction. They cleared the soil away, which contained the flints that had already been lying there for several thousand years, and then later used this earth to cover their cairn, inadvertently scattering the older relics over their new monument.

Peter also proposes the fascinating idea that Crowdy Marsh was once, thousands of years ago, a lake or pool, much like Dozmary, before becoming ‘clogged’ with peat. This would mean that the reservoir is in some ways recreating an ancient scene that might be much more familiar to our ancestors, if they were able to see it today, than we would naturally suppose. An amazing thought!

Final Thoughts

The more I learn about our prehistory the more I realise that the landscape has never been static, it has not always looked and will not always look as it does today. But stories like this one connect us in a heartbeat right back to our earliest roots. We can see those people and imagine their lives in our minds eye because we can place them in the landscape in front of us.


These days Crowdy Reservoir is a peaceful spot, a haven for Canada geese and a popular place for dog walkers. But as you take in the scene, as you watch the waves lapping at the banks, remember that the water is revealing inch by inch, flint by flint, a world that last saw the light 10,000 years ago.

Further Reading

The Cup-Marked Stones of Stithians

Kerbed Cairn on Alex Tor, Bodmin Moor

For more posts on the prehistory of the moor go to my Bodmin Moor page

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5 thoughts on “Crowdy Reservoir – Traces of Mesolithic Cornwall

  1. Maybe the Mesolithic flints were found by the Bronze-Age people who built the cairn, and, recognising that they had been left by their Mesolithic ancestors, placed them deliberately on top of the cairn as an act of homage or reverence?

  2. Another illuminating exploration of one of my regularly visited local dog walk sites, Elizabeth. I shall be keeping my eyes open for flint tools along the shoreline now, especially as the levels are getting so low at the moment and revealing the ground further than usual!

  3. I spend every visit to pebbley beaches on the north coast searching for flint. It’s amazing how much there is once you start looking

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