The earliest human occupation of Britain
Our January 2004 lecture was by Nick Ashton, a Palaeolithic specialist at the British Museum. He is currently participating in the Ancient Human Occupation of Britain project, which has been funded by the Leverhulme Trust. This 5-6 year study is being conducted by an association of a number of institutes, and aims to chart a biography of the first 500,000 years of the human occupation of Britain.
Evidence of the earliest humans in Britain is rare. Prehistoric British sites include a few caves, but most are open air sites, with remains being deposited in river and lake sediments. Finds include stone axes, scrapers, bone, teeth and shells. In some cases, wood, pollen and seeds have been found; this organic evidence helps environmental reconstruction and can be used to determine climatic trends.
Because carbon dating is only reliable for dates back to 35-40,000 years ago, other techniques can be used such as thermoluminescence which can be used to date burnt flint. Burning flint reduces its radioactivity to zero, but it gradually accumulates again through time from background radiation in the ground. The rate of this can be measured which allows the time of burning to be estimated. A second technique, amino acid racemisation, can also be used (del) to date organic remains, such as snail shells.
Evolutionary changes in small animals with rapid breeding cycles, such as voles, are particularly useful for dating sediments. Bones and teeth of larger animals can also be used as dating evidence: for example, Etruscan rhino died out in Britain approximately 450,000 years ago, and any sites containing their remains are likely to be at least this old.
Earliest Human Occupation
Britain has not always been an island. Certainly when humans first arrived here and possibly until a couple of hundred thousand years ago a 30m high chalk ridge linked Kent to northern France, and allowed passage to and from Britain - even when sea levels rose during warm interglacial periods.
The early human occupation of Britain has been divided into 5 periods, and was thought to begin some 500,000 years ago, during a warm interglacial. This is long after humans reached Europe probably in the form of Homo heidelbergensis approximately 1 million years ago. The earliest evidence for a human presence in Britain was found in Boxgrove, and dates to 0.5 million years ago. This site contained very good and almost undisturbed archaeology, and the presence of hand axes and flint tools helped to establish a human presence at the site.
Thirty thousand years after arriving, these first colonists were forced out of the area by a major cold phase that lasted 50,000 years and ended with the beginning of the Hoxnian Interglacial.
This time period began approximately 420,000 years ago, and ended about 360,000 years ago: it is characterised by temperatures one or two degrees higher than they are now. Finds from the excavation at Barnham, Suffolk, indicate the environment of this time. Seventeen species of amphibian and reptile were found, including tree frogs and Mediterranean snakes. The European pond terrapin was also recovered, but is not found north of central France and Germany in present times. This reptile buries its eggs in mud, and requires an ambient temperature in July of at least 18oC for successful hatching.
Elephant and rhino were also excavated at the site, together with a lion ankle bone which shows that the creature was 1.5 times larger than those of modern African lions. The site was located on a cobble beach on the edge of an ancient river about 400,000 years ago, and the cobbles were used as a raw material by humans. The site was so undisturbed that some of the flint flakes can be fitted back together to form the original cobble, and such reconstruction helps to illustrate how tools were created.
Britain was warm and wooded at this time, and evidence suggests these earliest human colonists favoured open river valleys surrounded by wooded slopes as sites of habitation. This was a rich environment, and the rivers were a focus of resources, including the attraction of large game. Humans probably lived in small social groups, and were primarily scavengers and opportunistic hunters of animals traversing the corridors of the open river valleys. The identity of this second wave of humans remains unclear, although Chris Stringer of the Natural History Museum has interpreted the sole skull found of this time period from Britain as bearing early Neanderthal features.
Temperatures seem to have been generally cooler during the Middle Palaeolithic, some 200,000 to 250,000 years ago, and the forests receded to leave open steppe and tundra upon which herds of large mammals roamed. This was the age of the Neanderthals, who developed new technologies of flint knapping. A flint core was prepared and used to make a number of flakes, all of which could be used as sharp edged tools. This ‘Levallois’ technology was much more efficient and economic than the shaping of a single tool from a flint nodule, and could also be used to provide a variety of tool shapes.
Well fashioned and balanced spears have also been found in Germany that date to this time, suggesting that the environment was sufficiently open to hunt at a distance. With more open landscapes, it is likely that humans hunted over larger territories, and were organised in larger social groups.
The Thames Valley has proved to be a useful location for the estimation of population densities. As the river has cut down through time, terraces have been formed, the oldest being the highest on the edges of the river valley, and the youngest being cut by the present flow of the river. The density of artefacts in each terrace is thought to act as an indicator of population density at the time the terrace was cut, and suggests that there was a decline in population size from 400,000 years before present, and a virtual absence between 200,000 and 60,000 years ago.
This may be explained by a breach in the chalk ridge that ran between Britain and Europe. Although the timing of this event is not known, the absence of humans after 200,000 years ago might provide evidence for the date. After the ridge was breached, crossings could only be made when the climate cooled sufficiently for large ice sheets to form and sea levels drop. Temperatures during this time may have been too low for humans to migrate north across the temporary land bridge and enter Britain.
The breach itself may have been caused by the rapid melting of a thick ice sheet that blocked the northern part of the North Sea. If this event can be dated to 200,000 years ago, the gradual decline in population may be explained, as colonisation would only be possible during periods of low sea-level and the formation of a land-bridge between Britain and mainland Europe, which only coincided with extremely cold.
Evidence for periodic re-colonisation dating from 60,000 years ago includes a mammoth butchery site, found in Norfolk. The climate at this time was very harsh, and it is likely that humans moved south when it became very cold, resulting in a number of evacuations from and re-colonisations of Britain. Modern humans replaced the Neanderthals some 35,000 years ago. Leaf point flint technology emerged shortly before this time, although it is not yet clear whether Neanderthals or Homo sapiens were responsible for the development.
An Even Earlier Human Occupation?
Very recently, a site has been found that may push back the date of the first human occupation of Britain to before 500,000 years ago. The new site is located on the foreshore of the Norfolk coast, and excavation is only possible at low tide. Tidal action and the presence of piddocks (a marine burrowing bivalve) puts this very rich site under threat: the cliff face has eroded backwards 30 m in a few months, yielding artefacts as more of the site is exposed.
Flint, stone, and bone - and even wood and plant remains - have been found at this site. Bison bone with cut marks provides evidence of human activity at the location, and analysis of the geology might suggest a date for the site of up to 700,000 years old. This is much older than any other evidence of human occupation in Britain, and is also older than any site yet found in mainland Northern Europe. It is hoped that further excavation of this site will help to confirm this date and provide further information about this very early human settlement.
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