Between 850,000 and 950,000 years ago a small party set out across the upper reaches of an estuary. The group was made up of at least five individuals, including adults and children, while the tidal mudflats they were navigating lay at the mouth of what is now the Thames. Flowing almost 100 miles north of its current course, the river debouched into the North Sea through modern Norfolk.
There is nothing to suggest that the group’s journey was in any way extraordinary. Its members ambled slowly in a southerly direction, following the course of the river and frequently making detours towards its channel. These people did not return the way they came, but they left a jumbled mass of footprints in their wake.
Those fragile impressions in the soft esturine clay proved remarkably durable. At high tide they were submerged and swiftly filled with the sediments that would preserve them for almost a million years. By the time the footprints reappeared, in May 2013, they were the earliest traces of a human journey in Britain.
The waters that exposed the ancient footprints at Happisburgh are no longer laying down sediments. Instead, that stretch of Norfolk coastline is retreating at an alarming pace. As we saw in Current Archaeology 288, the same waves collapsing cliff faces and demolishing houses are exposing the remains of long-extinct animals – and the earliest traces of human activity ever discovered in Britain. It was this archaeological silver-lining that brought Dr Martin Bates of the University of Wales Trinity Saint David (Lampeter) to Happisburgh last year.
‘I was doing geophysical survey with my brother Richard, to try and map the course of the ancient estuary channels under the modern cliffs,’ Martin explains. ‘As part of that work we lay out 400m of cable and put 80 electrodes into the ground. Our computer spends about an hour taking a series of measurements, and during that time we’ve got nothing to do. So we went and had a look at the deposits on the beach. And there in front of us was this strangely patterned surface.’
The footprints were exposed a short distance to the south of a site the team call Happisburgh 3. Eighty flint tools discovered there are believed to date back between 850,000 – 950,000 years, making them the earliest relics of human activity in Britain. If the footprints belonged to the same period, they would be one of the earliest sets in the world. Only the 3.5m-year-old footprints made by a human ancestor at Laetoli in Tanzania and the 1.5m-year-old examples from Ileret and Koobi Fora in Kenya are more ancient.
Previously the oldest human footprints in Europe were from Roccamonfina in Italy, which date back 350,000 years. So how could the team date the Happisburgh footprints?
‘It is really down to the sediments in which the footprints were made,’ explains Dr Nick Ashton, Co-Director of the Happisburgh Project and British Museum Curator. ‘Elsewhere along the coast, old estuary silts at a similar depth are associated with a range of animal and plant remains. Among them is a very early form of mammoth, for example, which we know became extinct about 800,000 years ago.’
‘The sediments themselves also provide a clue. At the moment, compasses point north, but in the past there have been periods when the Earth’s magnetic field reversed and a compass would have pointed south. Because these sediments were laid down very slowly, the iron minerals within them orientated themselves on the magnetic pole at the time. By measuring that, we can say they formed during a period of reversal. Putting all of this together narrows down the date to between 850,000 and 950,000 years ago.’
‘It was pretty lucky we had as long as we did,’ says Martin. ‘The sand on that beach is very abrasive, and the footprints were simply scoured away over a number of tidal cycles. I don’t know how long they’d been exposed when I saw them, but we are probably looking at a window of about a month in which they could be spotted and recorded before they were lost forever. There were about two weeks between the time when I said “This is what I think they are” and their destruction.’
‘The trail was about 3m wide and 10m long,’ Nick remembers. ‘Its recording took place over several days and used a technique called multiple image photogrammetry, undertaken by Sarah Duffy from York University. This takes a series of images from different angles and uses software to stitch them together into a 3D model. Using colouring to show different depths within the prints we could begin to see the various parts of the feet. In one we could even make out four of the five toes.’
Once the footprints had been recorded, they were studied by Dr Isabelle De Groote at Liverpool John Moores University. ‘These are clearly human footprints,’ she observes. ‘In the best-preserved prints you can see the heel, the arch of the foot and then the ball of the foot and the toes. Humans are the only ones who leave footprints like these. Other primates have a divergent big toe – that is, one coming out at the side. And humans do a very distinctive heel strike when they walk, rolling off onto the ball of the foot.
‘Both small prints and large prints were present. What I was able to do was measure the length and the width of the footprint in order to estimate how many individuals were there. Over the whole surface there were a huge number of hollows, and I ended up identifying a total of 49 that were clearly footprints. They were made by at least five different people, and there were at least two or three children in the group, the smallest of which can be estimated to have been about 3ft tall.
‘The largest prints, of which there are three, come from a single individual with the equivalent of a modern UK size 8 foot and a height of about 5ft 8in. We believe that this is likely to be a male. A slightly smaller individual could be an adult female, or perhaps a young adult male. There’s no reason why we should not think of them as a family, but because we’re only seeing the prints of a few individuals we cannot be certain whether it was a single family unit or a larger group.’
This is an extract, but you can read the full feature in CA 289
The footprints were carefully recorded, but the nature of the sediments meant they could not be lifted and have been completely eroded away. It is hoped more will be found and, given enough time and resources, can be preserved.
The scientific publication is available online at www.plosone.org/article/info%3Adoi%2F10.1371%Fjournal.pone.0088329
The excellent Natural History Museum exhibition Britain: One Million Years of the Human Story provides an opportunity to learn more about the footprints, and to see all the early human remains discovered in Britain. It runs until 28 September. For more details of the exhibition, see www.nhm.ac.uk/britainmillionyears
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