Fauna, flora, flint artefacts and fire from 400,000 years ago
An old clay pit in Barnham, Suffolk, has been yielding remains of early human activity for over a century. Renewed excavations are finding exceptional evidence for animals and vegetation, with flint artefacts and signs of fire from 400,000 years ago. Nick Ashton, Rob Davis, Simon Lewis and Simon Parfitt report on a site of international significance
When Euston Hall burnt down in 1902, no one could have predicted that it would have an impact on Palaeolithic archaeology. The hall was the seat of the Duke of Grafton, whose family had already played a role in scientific discovery when a cousin, Robert Fitzroy, captained hms Beagle and set sail with Charles Darwin in 1831. Over 70 years later the clay pit at Barnham rapidly expanded to make bricks for the rebuilding of the fire-struck hall. Discoveries of elephant bones and handaxes were soon recorded from the pit and so the site entered into the annals of the British Palaeolithic.
The now wooded clay pit, just south of the quiet village of Barnham in Suffolk, is still being investigated today. Seasonal excavations since 2013 are fast establishing it as a critical site for understanding our distant relatives from some 400,000 years ago.
Life around a pond
The site lies in a dry valley, flanked by Chalk, till – mixed glacial debris – and glacial gravels, which also underlie the valley-bottom sediments. The glacial deposits were laid down by ice sheets in the Anglian, the most extensive of the British glaciations, some 450,000 years ago. As climate warmed and the ice retreated, a new drainage system with rivers, lakes and ponds was established across the glacially remoulded landscape. One such pond at Barnham gradually filled with grey silty-clay through the first half of the warm period – the Hoxnian Interglacial (425,000–390,000 years ago). As the pond became choked with sediment, vegetation encroached and soil developed across the basin, marked by a thin black clay or palaeosol, an ancient soil, sealing the underlying grey silty-clay. Hillwash and other slope deposits, consisting of brown clays or “brickearths”, then gradually filled the valley bottom.
The grey silty-clay reaches a depth of 5m in the centre of the basin and preserves a remarkable environmental record; it has been excavated in Area iii, one of the places where we are working now (see plan opposite). Pollen preserved within the sediments charts the vegetational succession from open tundra, through the arrival of pioneering birch and pine, to the establishment of full deciduous woodland. Remains of molluscs and vertebrates also survive. A wide range of fish, such as trout, tench, roach, rudd and pike reflect still or sluggish water with a stream connection to the local river network. Over 17 different species of amphibians and reptiles have been found, with everything from frogs,
toads and newts to snakes and lizards. European tree frog, pond terrapin and Aesculapian snake require long, warm summers for breeding, suggesting that temperatures were at least 2° c warmer than present-day averages of 17° c.
There is an even wider range of mammals; moles, voles, water voles and shrews abound alongside more unusual species, such as the semi-aquatic Russian desman that today inhabit wetlands in the valleys of the Don, Volga and Ural rivers. We have also found remains of rabbit, squirrel and badger, together with wild boar, red and fallow deer, and aurochs (large wild cattle). Teeth and bones from extinct rhinoceros and elephant survive as fragments, perhaps trampled underfoot by their relatives. The elephant is the straight-tusked form, whose bulls stood up to 4m high, weighing in at almost 10 tonnes. Some of the foot bones from a particularly big cat have yet to be identified to species, but may be from an extremely large lion or the sabretoothed Homotherium.
Together, the plant and animal remains paint a vivid picture of a small, stream-fed pond, rich in wildlife, surrounded by a mosaic of open grassland and mixed oak forest. This small backwater, off the main valley, was a focus for watering game including deer, bovids, rhinoceros and elephant, with the occasional lion or sabretoothed cat lurking in readiness for the next kill. But the large cat was not the only hunter. Humans were also visitors to the site.
Humans come & go
The grey silty-clay thins towards the fringes of the former pond, so that at the edge it is less than 30cm thick. Unfortunately it is decalcified there, so bone does not survive. The silty-clay immediately overlies coarse lag gravel consisting of large flint cobbles. The cobbles formed a valuable source of flint for making tools, and most of our human evidence consists of the flakes, flake tools, cores and a few handaxes that they left behind. The artefacts mainly occur on and in the cobbles and within the overlying silty-clay, which was then sealed by the same palaeosol as found above the pond deposits.
From work in the 1930s the site had been one of the flagships of the “Clactonian v Acheulean” debate, where people with simple flake tools (Clactonian) were said to have been succeeded by a group who benefitted from more sophisticated handaxes (Acheulean), although this had never been properly demonstrated. Our work in the 1990s appeared to show that this was not the case, and that we were dealing with a single human group (see feature May 1995/4).
One of the basic rules of archaeology should be to never re-excavate one of your own sites – you will almost certainly end up with a different interpretation. This is indeed what happened. We had originally dug Barnham in the early 1990s, and came to a reasonable conclusion that in one area of exposed cobbles (Area i) a human group were simply making flakes and tools from cores. And only 50m away (in Area iv4) the same group were also making the occasional handaxe on the same cobble surface – a simple case of doing different things in different places.
Since 2013 we have opened up new trenches that bridge the 50m gap between Areas i and iv4, revealing a more complex geological situation. We have now established that the core and flake assemblage is indeed associated with the cobble surface, but the handaxes are being recovered from the overlying palaeosol. The new sections in Area iv4 show that the palaeosol did not develop in this part of the site, and that the cobbles were exposed for longer, allowing handaxemakers to work on the same surface at a later time. In this area we have a palimpsest of two different assemblages on the cobble surface, which are separated out into different sediments in other parts of the site.
When did the first group arrive? To address this we need to examine the artefacts that are thinly dispersed in the grey silty-clay in the middle of the pit with the detailed environmental sequence. The Hoxnian is divided into four successive pollen zones ( i-iv), but just the first two of the zones are represented at Barnham. So far most of the artefacts are from the top 1m of the grey silty-clay, which suggests that the first group arrived during zone ii, when deciduous forest was becoming established. But we have dug only small areas that go deeper into the silty-clays, and we need to expand these excavations to really answer this question.
Further questions are when did the handaxe-makers arrive, and how long after the the first group left? Could their arrival be linked to the environmental disruption of widespread deforestation seen across northern Europe, perhaps caused by volcanic clouds or a meteor strike? Handaxes first appear at the very top of the sequence as the pond was drying out, vegetation encroached and the soil developed. This seems to correspond with either the end of pollen zone ii or beginning of zone iii as the oak forest matured. But we need better pollen preservation at the very top of the sequence to see whether the second human arrival corresponds to the deforestation event. It is difficult to measure the time gap between the groups, but it could have been a few generations or less.
Burning question
Around the fringes of the basin are concentrations of burnt flint and occasionally burnt artefacts and charcoal, associated with the handaxes in the palaeosol. For some reason charcoal has rarely survived. But was the burning caused by people or was it simply a natural forest fire? The high density of burnt flint in one area suggests human fire-use, but could that be an indication of a lightning strike or other more limited natural fire? Answering these questions is not easy, so we have adopted a cautious approach using an array of geochemical and experimental techniques.
Infrared spectroscopy is one of several methods that we are using to determine burning of sediments and the likely temperatures. Initial results show that some of the sediments were heated, suggesting localised burning. Much more laboratory work is required and this is only one step on the journey to establishing fire-use.
The geochemical work is also part of a series of fire experiments where we can begin to control some of the variables. The first experiments by Josh Hogue and Becky Scott have been designed to understand the effects of burning on flint and sediment within, beneath and adjacent to a fire. They have used probes in different locations to establish temperatures during and after the burning with set parameters, such as sediment type, wood type and weight, and duration of feeding the fire. Once the hearths are cold, they have excavated them, taken sediment samples and recorded the effects on flints.
There are many experiments to
go, but a few consistent results are beginning to emerge. It seems that temperatures tend to be about 500° c at the base of the fire, can reach 400° c in the ground beneath at 5cm down, but then drop off rapidly to about 100° c, where flint is not visibly altered. Flint in the centre of the fire is reduced to little more than dust, but towards the edge of the burning it has the characteristic cracking and reddening that we find with the archaeological burnt flint. Finally, longer burning may have a different effect on flint and sediment alteration. Forest fires tend to sweep through and burn quickly, whereas intentional fire is usually fed, and burns for longer. The experimental and archaeological results need to be compared to those from forest fires. Fortunately Thetford Forest is on our doorstep, where over 100 natural fires were recorded just last year, some of which were in deciduous woodland. With Forestry Commission help we hope to gain a better understanding of the effects of natural fire and make another step towards understanding the burning at Barnham.
Around the hearth
If fire-use can be identified at Barnham, it would be one of the three oldest sites in Europe with this evidence, all dating to about 400,000 years ago. One site is Menez-Dregan in Brittany, while the other is Beeches Pit near West Stow, a mere 10km down the road from Barnham. The fire at Beeches Pit is associated with flint tools including handaxes, as at Barnham, but more distinct hearths with burnt sediments have been identified.
The three sites have another feature in common – they are located in safe or peripheral parts of the landscape. Menez-Dregan was once a coastal cave looking south over the Bay of Biscay; humans had out-manoeuvred cave bears, lions or hyaenas for its use. Beeches Pit was sheltered beneath a chalk bluff on the fringes of the Lark valley with a spring-fed pond for fresh
water. It is now becoming apparent that Barnham was in a similar landscape position, being near the head of a small, wooded valley, away from the main river valley of the Little Ouse.
Remains at many of our early Palaeolithic sites occur in river sediments, which were once open floodplains of the Thames, the former Solent or their tributaries. Even Boxgrove, the 500,000-year-old site near Chichester, West Sussex, was on an open coastal strip (feature Oct 1996/18). These were ideal hunting grounds with large herds of herbivores, but after dark they would have been treacherous places to camp. So with Barnham, Beeches Pit and MenezDregan, we are perhaps seeing a different aspect of life – the safe havens that today we call home.
Fire would have been a critical ingredient. Not only did it provide warmth and protection, but cooking killed pathogens and removed toxins, opening up a new array of food sources. Cooked meat freed up energy use in the gut, which could be exploited by that energy-hungry organ – the brain. Perhaps its most significant contribution was providing evening light and becoming a hub for social interaction. Was it around the hearth
that the development of language, the beginnings of story-telling, and the emergence of early belief systems set us on the path towards the social animal that we are today?
Who were they?
We need to look to Europe to find out more about the successive groups of people who made Barnham their home. The first group with a tradition of core and flake manufacture probably entered Britain as the climate was warming in the first part of the Hoxnian Interglacial. Elsewhere we can see groups with similar material culture at Clacton, Essex, and the lower levels at Swanscombe, Kent. If we dig deeper at Beeches Pit we might also find evidence there. The second group, of handaxe-makers, seems to have arrived towards the peak of the interglacial and can also be seen at Swanscombe and Beeches Pit.
So where in mainland Europe might these people have come from? The situation is complex. Very few sites can be dated with the same precision as those in Britain. We also find a myriad of stone tool assemblages, some with and others without handaxes. People used different raw materials in different regions, some of which were less suited to making handaxes. At some sites in Italy archaeologists have found handaxes made from elephant bone, while several cave sites in France have handaxes in some levels, but not in others.
One way to interpret this complexity is to view the differences as showing localised material cultures that in part reflect the resources available and the needs of individual groups. Stylistic differences emerge, shown by handaxe form or other material possessions, and become embedded traditions. The different assemblages can be seen as a photo-montage that is difficult to disentangle due to the problems of dating and correlating the sites. In Britain we have the benefits of being a cul-de-sac of Europe, where we have clear images of at least two of these groups that happen to make the journey across the narrow land-bridge that probably still connected us to Europe.
The problem in making sense of the different material cultures in Europe seems to be increasingly mirrored by the
complexity in the human fossil record. Until recently, the fossils were divided into Homo heidelbergensis and early Homo neanderthalensis. But now some fossils seem to have features of both, while the status of H heidelbergensis has also been questioned. New adna work highlights the complexity, but also promises to bring better understanding.
As for Barnham, we will continue working to try and answer this and many other questions. It is a critical time in history, when humans had a more sustained occupation of Europe and new technologies such as fire-use began to emerge. Critically, brain-size had approached modern levels, increasing memory, enabling more complex relationships, better communication and the building of wider social networks that distinguish humans from our closest primate cousins. It is hoped that among the excellent bone preserved at Barnham we will find human fossils, giving us critical clues to the emergence of humans 400,000 years ago.
This feature is written on behalf of the Barnham project staff: Claire Harris, Marcus Hatch, Peter Hoare, Josh Hogue, Sophie Hunter, Tudor Bryn Jones, Mark Lewis, Claire Lucas, Jordan Mansfield, Simon O’Connor, Sylvia Peglar, Becky Scott and Craig Williams. The work is being undertaken with the generous support of the Euston Estate, the Heading family and pr International. The research is part of the Pathways to Ancient Britain project, funded by the Calleva Foundation, and of the Breckland Palaeolithic Project, funded by the Leverhulme Trust. Nick Ashton is curator of Palaeolithic & Mesolithic collections and Rob Davis is a postdoctoral research assistant, both at the British Museum; Simon Lewis is professor of Quaternary science, at the School of Geography, Queen Mary University of London; Simon Parfitt is a principal research associate at ucl
In Britain we have the benefits of being a cul-de-sac of Europe