With the help of many dedicated local collectors, AHOB has gathered much more evidence from Happisburgh and, despite the cold and the tides, has carried out three excavations there, showing that this was indeed a site of ancient human occupation at least 500,000 years ago. Several other large bones show cut marks and impact damage, suggesting they were processed for meat and marrow, and this is backed up by the recovery of more than fifty flint flakes and a second handaxe. Over seven tons of excavated sediments have been collected and washed through fine sieves either on site or back in the museum, producing rare remains of smaller animals, including fish, birds and amphibians, with the only British record of an extinct kind of frog called Pliobatrachus. The clayey sediments also contained well-preserved remains of plants such as pollen, seeds and wood, and of beetles, suggesting that the artefacts and bones were deposited in the backwater of a large river bordered by coniferous woodland, near the peak of an early Middle Pleistocene warm stage (interglacial). The river system will be discussed later, but which interglacial was it? Here there are two somewhat contradictory interpretations of the evidence within the AHOB project. Amongst the small mammal remains found in the sieves are teeth of Arvicola, suggesting that the site is about the same age as Boxgrove, assuming the overlying deposits in the cliffs are debris from the Anglian ice sheet advance. But there is another possibility. Jim Rose of AHOB believes that the Anglian was not, as commonly believed, the first ice sheet to push down across East Anglia. He and colleagues argue that there was an earlier ice advance about 650,000 years ago, which came down the British mainland rather than across from Scandinavia, picking up a distinctive Scottish suite of rocks as it did so. Jim argues that the deposits above the Happisburgh handaxes and bones show the distinctive geological signatures of the earlier ice advance – in fact Happisburgh has been designated as the type-site of this newly recognized glaciation. In which case the evidence of human occupation at Happisburgh would be an astonishing 700,000 rather than 500,000 years old. However, other workers, within and outside AHOB, dispute this view.
This ongoing debate about the geology of East Anglia is critical to the dating of many sites beyond Happisburgh, and before we move on to discuss another and even more important site it is worth spending a little time looking at what we know about the quite different landscapes and geography of the region more than half a million years ago. Britain was then a peninsula joined to the Eurasian continent by a wide land bridge, whose spine was a chalk ridge running between what is now the south-east of England, and France. Many of today’s river systems, for example the Severn and Bristol Avon, did not exist. Others were on different courses, such as the Thames, which flowed along a more north-easterly course through the Vale of St Albans towards Clacton and Colchester. Rivers also flowed from the Pennines and the Midlands that have since completely disappeared – for example, the Mathon River flowed southwards through Herefordshire, and a mighty river called the Bytham, 300 kilometres (200 miles) long, flowed south and then eastwards across East Anglia. Several important archaeological sites lie along the route of the lost Bytham, including Waverley Wood near Coventry, which has produced early handaxe tools, and AHOB sites High Lodge and Warren Hill near the border between Norfolk and Suffolk. The Waverley Wood handaxes are distinctive because they are made of quartzite and the volcanic rock andesite, rather than flint, but the workmanship is every bit as skilful as in more typical examples. When the ice of the Anglian glaciation advanced to its maximum extent, it obliterated many of the old rivers, and pushed the Thames southwards. At the height of the cold stage a massive front of ice sat over the Midlands and north London, and south of it were huge lakes filled by spring thaws and ice-dammed rivers, such as the Thames. One known as Lake Harrison spanned Leicester, Coventry, Rugby and Leamington, and when another eventually burst its banks near Hillingdon, just west of London, a catastrophic flood freed the Thames, where it took over river valleys such as the proto-Medway to form at last its present estuary.
Dating before these ice age dramas, High Lodge, near Milden-hall, remains an enigmatic site. Despite 150 years of excavations, its extraordinary history is only now becoming clear. Workmen who were digging clay for the manufacture of bricks discovered the first artefacts in the 1860s, and ten years later John Evans (one of de Perthes’ supporters, who we encountered in the previous chapter) noted that tools looking Middle Palaeolithic seemed to underlie ones that were Lower Palaeolithic, an inversion of the expected succession. Several excavations followed over the next ninety years, and all found the same peculiar sequence of artefacts. The most recent pre-AHOB excavations found evidence from fossils and overlying glacial deposits to show that the site was pre-Anglian, and our subsequent work has recovered more stone tools, fossil mammals such as the extinct giant beaver, and large chunks of wood. Both the artefact assemblages are indeed pre-Anglian, so the ‘Middle Palaeolithic’ ones, despite their refinement, are clearly very ancient. And the deposits that contain these artefacts were probably originally from an interglacial lake or river that was frozen solid in the subsequent Anglian ice age and was bulldozed miles across Norfolk enclosed within glacial debris as a gigantic glacial erratic. The nearby site of Warren Hill has long been known as a site for handaxes, perhaps the most prolific one in the country. Our excavations exposed a shallow marine or tidally deposited sand at the base of the sequence, without artefacts, and upper deposits from a southward-flowing part of the Bytham River system containing handaxes, and knapping debris from their manufacture. We also found large heaps of a fine gravel spoil, apparently the dumps of collectors sieving for handaxes more than a hundred years ago.
As the Bytham River slowed past Warren Hill towards its delta on what is now the East Anglian coast, it deposited sediments on the edge of a huge north-facing bay, into which the Rhine also flowed. The sites of Norton Subcourse in Norfolk and nearby Pakefield, just over the border in Suffolk, were probably both related to the Bytham, and they record a time when the climate of Britain was balmy and Mediterranean, and this part of East Anglia was a fertile estuarine plain. Norton Subcourse has a working quarry for sand and gravel, and in its depths are rich clays, silts and peats, containing evidence of a fen surrounded by reeds and alder. AHOB excavations have found the bones of amphibians, reptiles and fish such as carp and pike, and of mammals such as an extinct ass-like horse, elephant, deer and hippos, with remains of the latter showing gnaw marks on their backbones. Nearby, piles of bone-rich hyaena droppings lie just as they were deposited some 700,000 years ago, and we can imagine the hyaenas climbing on to the backs of dead hippos in the swamp in order to feed. Amongst the small mammal remains are teeth of Mimomys, confirming that Norton is indeed older than Boxgrove and Happisburgh.
About 30 kilometres (20 miles) downriver, on the Suffolk coast near Lowestoft, is Pakefield, and this small town has now entered the archaeological hall of fame, sitting alongside Boxgrove, Swans-combe and, at a much later date, Stonehenge. The site, like Happisburgh and so many others in East Anglia, lies under a cliff of glacial deposits, and for over a hundred years has been producing fossil bones of animals such as hippo, rhino, primitive mammoth, straight-tusked elephant, bison, three species of extinct giant deer, and carnivores such as scimitar-toothed cat, lion, hyaena, wolf and bear. Also there was the primitive vole Mimomys, rather than its descendant Arvicola, suggesting that this was a relatively old site in the East Anglian sequences. But in the last few years, field visits and local collectors have reported finding flints that looked as if they were struck off by humans, and that has made the site of particular interest to AHOB. Expert examination confirmed that these were indeed humanly worked, but did they really come from the muddy layers under the glacial deposits that were producing the fossil mammals, or could they have been washing down from the fields above the glacial deposits? There was only one way to settle it, and so AHOB worked with the local collectors to carry out further excavations and publish the evidence. These put any doubts to rest and there are now thirty-two
worked flints including a core and several retouched flakes. The artefacts are in sharp condition and are made of good quality black flint that was probably picked up in the form of river cobbles. The oldest was found in river estuary deposits where, along with the discovery of rare bones of dolphin and walrus, associated microfossils suggest brackish water. The
remaining artefacts were found higher up in dark sediments from the riverbed or riverbank.
Pakefield has produced other valuable material in the form of incredibly rich remains of wood, plants, beetles, molluscs and microfossils, all of which can help paint a vivid picture of the area when the first Britons were there, including very detailed climatic information. There are over 150 plant species, including water chestnut, floating fern, brittle waternymph and broom crowberry, suggesting warmer summers than today. Thousands of beetle fossils represent nearly a hundred different species, including exotic diving species and others that live in rotting wood. Mutual Climatic Range analysis of the beetle assemblage looks at the tolerances of the different species today in order to work out what kind of climate would have been compatible for all of them, and this also suggests July temperatures between 18 °C and 23 °C, compared with 15 °C today, while the coldest months (January/February) were mild. In fact we know from the plants, the presence of animals like hippopotamus, and the species of fish and amphibian that winter temperatures were above freezing. And we can even reconstruct rainfall patterns, as the sediments contain carbonate nodules which developed in the soil and which preserve a chemical snapshot of the local climate at the time they formed. Study of the proportions of oxygen and carbon isotopes in these nodules give AHOB researchers a window into ancient climates. The soil carbonates indicate an annual moisture deficit, whilst their isotopic composition reflects intense soil moisture evaporation during their formation, so there was strong seasonal rainfall. The combination of warmer and drier summers and cool wet winters indicates a Mediterranean climate, something unique for a British archaeological site.
The insects, plants, molluscs and other fossils can also tell us about the landscape, suggesting marshy ground with reeds and alder trees near a meandering and extensive river estuary, with pools of different depths, while oak woodland and open grassland grew farther from the river. This mixture of landscapes would have supported the many different browsing and grazing mammals known from Pakefield, from the size of elephants and hippos down to deer, and also would have attracted their predators and scavengers, from lions to foxes. The floodplain provided an environment rich in plant and animal resources for the humans as well, and most importantly in an area without much rock there were flint-rich river gravels for stone toolmaking. This knowledge of the setting makes interpreting the stone tools difficult, though. The simple form of the core and flakes might indicate a primitive pre-handaxe technological tradition, in line with interpretation of the tools at Ceprano and Gran Dolina. However, the Pakefield tools are few in number, and were being made from water-worn pebbles, probably not suited for the manufacture of large flaked tools like handaxes. But are there other clues to the age of the artefacts at Pakefield?
As at Happisburgh, the river sediments containing the tools at Pakefield are stratified below glacial debris and outwash deposits, so they must date from before the Anglian cold stage of about 450,000 years ago, at least. Jim Rose and colleagues argue that the deposits sandwiched above the tool-bearing layers and below those of the Anglian (high in the cliff) show at least two cycles of high sea levels, with cold periods between, which must indicate at least two separate periods of small ice caps (and therefore interglacials) after the Pakefield interglacial and before the cold of the Anglian. They would place the Pakefield interglacial at least as far back as 700,000 years, and perhaps even earlier. Others in AHOB are not sure about this geological approach, and instead rely on the fact that the interglacial at Pakefield is warmer than any of the ‘Cromerian’ (after Cromer in Norfolk) interglacials so far known and dated at 500,000–600,000 years, and on the presence of two important species of the vole Mimomys. One is the familiar species Mimomys savini, placing the site as older than Boxgrove, Mauer and Happisburgh, all of which have the descendant form Arvicola. A second Mimomys species, M. pusillus, is extremely rare in Britain and is not known anywhere in the world after about 650,000 years ago. For our purposes, the important fact is that the geological, climatic and vole clock methods all date the stone tools from Pakefield as far back as 700,000 years ago. And there is one more bit of science that backs this up.
Amino-acid dating is based on the principle that the twenty amino acids that make up living proteins start to change once an organism dies. Most amino acids in proteins have one or more asymmetric carbon atoms and in living things these extend to the left side. However, for each one, there is an alternative isomer where the asymmetric carbon atoms extend to the right side instead (these are like mirror images of each other, just as right and left hands are). The isomers can be distinguished by whether they bend a beam of polarized light to the right or left, and the interesting thing is that after its death, in a process called racemization, the proteins of an organism start switching to their isomers at a steady rate dependent on temperature and time. Thus the more racemization that has occurred (all other things being equal), the longer the time since the organism has died. Amino-acid dating has been used on many different fossil materials including human and animal bones and teeth, plants, eggshells and shellfish. The technique has undoubtedly had a chequered history as a dating method, but AHOB associate Kirsty Penkman has used a new and refined procedure on shellfish that lived in the ancient river muds at Pakefield, and she compared results with other British sites. Those from Pakefield show a high degree of racemization compared with sites with Arvicola commonly dated to 400,000 and 500,000 years ago, and are similar to or slightly more racemized than Cromerian sites with Mimomys dated at about 600,000 years. And we know that none of these interglacial sites were as warm as the Pakefield interglacial, so that one has to be older.
Geology, climate, voles and amino-acids together place the stone tools from Pakefield at least 700,000 years ago, making them by far the oldest evidence we have for people in Europe north of the Alps. As we have seen, there has been much discussion about what additional social, technological or bodily adaptations humans would have needed to colonize north-west Europe compared with their occupation further south, but the Mediterranean climate reconstructed for the archaeological levels at Pakefield implies that these pioneers spread northwards in familiar climatic conditions. In accepting the stone tool evidence from Pakefield that required him to modify his Short Chronology model still further, Wil Roebroeks pointed out that the palaeoenvironmental evidence showed that the tools were discarded along the shores of an early Middle Pleistocene ‘Costa del Cromer’. In this sense the Pakefield evidence still supports the Short Chronology in that this was probably a brief episode of rapid migration north under favourable conditions, really requiring little more of people than what was
needed in Italy or Spain. Substantial occupation of, and adaptation to, northern Europe probably still only happened at the time of Mauer and Boxgrove. But if even within England, Roebroeks added, one of the best and longest researched parts of the world, surprises like Pakefield could turn up, what else was still to come? Even as this book is being written, there certainly promise to be yet more revelations from the sites of East Anglia…
AHOB has opened an entirely new window on the first Britons, pushing their date back 200,000 years beyond Boxgrove and 300,000 before Swanscombe, and in doing so has emphasized how long our prehistory is and how little we still know about it. It has also completely changed our view of the early colonization of Europe, as we now know that humans had reached the north-west edge of the inhabited world (apart from Ireland, which always remained out of reach in the Palaeolithic) some 700,000 years ago. The routes they took into Britain are unknown, but there were probably at least two. If they followed the valley of the ancient Rhine
westwards they would have arrived at the huge north-facing bay into which the proto-Thames and Bytham also flowed, and their valleys would have provided good routes into the British peninsula. If they came from the south they could have followed the valley of the Somme until it reached the Atlantic, and then crossed the chalk ridge into southern Britain. From there, they could have travelled west along the coastal plain or northwards up river valleys such as the proto-Solent, or the precursors of the Vales of Gloucester and Evesham. Up to now, we have not mentioned that most significant part of our present geography, the English Channel, because it did not exist then, but its development will loom large later in the book. Before we get to that part of the story, we will look in the next chapter at the human colonization of Britain, when humans of the species Homo heidelbergensis arrived. We will also examine how the evidence to date these early arrivals has been pieced together from records on land and from deep in the oceans.
CHAPTER TWO
Understanding Ice Ages
In the last chapter we saw how new discoveries have changed our views of the first peopling of Europe, and Britain. But although we can build a good picture of the landscape and the climate, the evidence of human behaviour itself is fragmentary: from the glimpses we have at places like Atapuerca and Pakefield, it is difficult to build much of a picture of what life was like for these European pioneers. Moving on in time, however, the evidence is suddenly much richer: we can point to a spot in the ground a few miles from the city of Chichester in Sussex and confidently say that this was where someone squatted down to make a flint handaxe about half a million years ago, and even show how they made that handaxe. We can also reconstruct in detail how these tools were used to expertly fillet meat from the carcass of a horse, a deer or a rhino. I’ll now unravel how we know these things, and how we know the age of the ancient sites in which this evidence is preserved.
Homo Britannicus Page 6
