Hunting for cave art
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Editor Simon Denison
Great sites: Grimes Graves
Peter Topping recalls early excavations at the Neolithic flint mines in Norfolk, which many archaeologists thought for years were Palaeolithic
The haunting, pock-marked landscape of the Neolithic flint mines at Grimes Graves, in the Norfolk Breckland, is one of the most eerily evocative sites in Britain, particularly on a mist-shrouded early spring morning with woodlarks singing overhead. Prehistoric flint mines are exceptionally rare sites in Britain and Grimes Graves offers visitors a unique opportunity to descend into a Neolithic mine, and experience a little of what it was like to be a miner grubbing out the black flint in the cool, claustrophobic low galleries.
A recent survey by English Heritage found that Grimes Graves was one of only ten Neolithic flint mines known in England, of which only six survive as earthworks. Dating from roughly 3000-2000 BC, mining began at the site during the later Neolithic and continued for a while into the Bronze Age. The Anglo-Saxons believed the site was the work of the god Grim - the place-name means 'Grim's quarries' - so perhaps they had some notion of what the site might once have been.
Later antiquaries were wider of the mark. William Camden (1695) described the site as 'small trenches and ancient fortifications', while F Blomefield (1805) interpreted what he saw as a 'Danish encampment'.
The available radiocarbon dates suggest that mining may have taken place over a period of between 500 and 1,000 years. The mines were sunk at a rate of one every one or two years. Mining was therefore neither intensive, nor on an 'industrial' scale, as we understand the term today.
The geology at Grimes Graves comprises a number of flint layers lying below sands and clays and interspersed between chalk. It was the upper three seams of flint which were exploited, and the lowest of the three, known as 'floorstone', was generally targeted because it was easily flaked, less flawed than flint from the other layers, and had a lustrous deep black colour.
To get to the flint the Neolithic miners dug shafts up to 12m deep with radiating galleries at their base, as well as shallower pits from 3m to 8m deep. Some mines are grouped together with two or three in a single quarry, implying that some were dug in sequence.
The surface mounds and hollows cover 7.6 hectares - although excavations suggest a more extensive area may originally have been mined - representing 433 mine shafts, pits, quarries and spoil dumps. Since the 1860s, at least 28 mines have been excavated, providing a rich history which at times reads like a soap opera.
Around 1820 coniferous woodland was planted over the mines, and was well established by the time a sketch was made in about 1850 by the Reverend Luke from nearby Weeting. The first excavations occurred soon afterwards in 1852 when the Reverend Pettigrew dug two pits and Reverend Manning separately opened others. In 1866 Reverend Manning returned and excavated further pits. All of these early digs are poorly recorded.
Perhaps the most significant excavations occurred in 1868-70 when Canon Greenwell was able to demonstrate - for the first time anywhere in Britain - that flint mines were prehistoric in date. Greenwell discovered the existence of deep shaft and gallery mining, he identified the red deer antler as the main mining tool, and from the discovery of a stone axe in one of the galleries deduced that they belonged to the Neolithic period. Consequently the shaft that Greenwell dug at Grimes Graves has a pivotal place in the history of archaeological research. It was reopened and further excavated by the British Museum between 1974 and 1976.
Greenwell discovered numerous antler picks scattered throughout the mine as well as the ground stone axe made of greenstone from Cornwall. The gallery in which this axe was found had impact marks from its blade cut into the chalk walls. The axe was lying at the ends of two antler picks which had been placed side by side on the gallery floor with their tines facing inwards, between which lay the skull of a rare shore bird (a phalarope). Clearly this was not fortuitous but a setting of important artefacts - both the skull and axe had been brought from some distance - perhaps arranged by the miners when the gallery had been worked out. The skeleton of a dog was found in another gallery during the British Museum's excavations. Neolithic Grooved Ware pottery, cups, a phallus of carved chalk and evidence of flint knapping were also recovered.
By the turn of the century doubts were being expressed as to the authenticity of the Greenwell axe as some archaeologists returned to the belief that mining was Palaeolithic in date. The question of the axe was not resolved until William Alan Sturge published his exhaustive researches into the details of how it was found in 1908, including an interview with Greenwell himself.
However, by 1914, following further erroneous suggestions published in 1912 by Reginald Smith, maintaining - despite Greenwell's discoveries - that flint mining at Cissbury on the South Downs and Grimes Graves was of Palaeolithic origin, the shaft known as Pit 1 was opened by AE Peake to provide dating evidence. Pit 1, 9m deep, is the only flint mine shaft in Britain that currently allows visitors to enter the underground world of the Neolithic miners. Five hearths were discovered at intervals in the backfill, suggesting that the shaft had been filled in stages, with fires being lit periodically, perhaps as some form of commemoration or dedication, or during ritual feasting.
At the base of the shaft, six horizontal galleries were found, extending for over 15m in some cases. Peake's excavation produced a wide range of finds - rope marks above the entrance to gallery II, numerous antler picks scattered about the workings, the remains of a red deer in gallery XV, sherds of Neolithic Grooved Ware pottery, flint implements, carved chalk 'cups' and balls, and the remains of three different species of bats.
Many of these finds are not mining tools, and suggest that the mining process was accompanied by other activities. The presence of bats demonstrates that some mines were left open long enough for roosts to become established - they were not quickly backfilled after their useful life had come to an end.
The shaft known as Pit 2 was also excavated by Peake in the same campaign in 1914-15 and reopened by the British Museum in 1975. Again the shaft was 9m deep, and as in Pit 1, a number of hearths were found in the fill of the shaft. Many layers of this backfill produced animal bones, indicating feasting or offerings placed in the mineshaft. Midway down, the jumbled remains of a female skeleton was found, but it is unclear whether this was a post-Neolithic burial near the shaft disturbed at the time of excavation, or a casual Neolithic interment thrown into the shaft.
A hearth was discovered at the base of the shaft, while a chalk and sand platform was found abutting the north-east wall. On the shaft wall near the platform, a group of vertical incised lines was found which would have been lit by the sun's rays at midday. These were interpreted as a 'sundial'. A second graffito - a lattice design - was found on another part of the shaft wall, and this was thought to be a group of 'tally marks' scratched by the miners as they counted flint nodules. Ten galleries radiated out from the base of this shaft. Later Neolithic Grooved Ware pottery was found in various galleries and at the base of the shaft, and several galleries produced bat remains.
This evidence again broadens our interpretation of the attitudes and activities that lay behind flint mining, suggesting that pottery deposition, feasting, the making of offerings and graffiti all played a part.
The earthworks surrounding Pit 2 still tell us something of Peake's excavations. On the north-eastern side, a narrow cut can be seen through the lip of the shaft - this was the wheelbarrow run leading from the dig to the spoil dump. On the south-western side we can still see a second spoil dump partly filling another shaft.
During the inter-war years a number of individuals, particularly Leslie Armstrong, continued to try to find evidence for a Palaeolithic date, even after publication of the 1933 paper written by Clark and Piggott which conclusively demonstrated the Neolithic date of flint mining.
Armstrong's work at Grimes Graves reached its climax when he excavated Pit 15 between 1937 and 1939. This shaft was relatively shallow - the 'floorstone' was encountered at a depth of 6m - and nine galleries radiated out from the base of the shaft.
The excavation of this flint mine was one of the most controversial at Grimes Graves, particularly because of the discovery of the famous chalk 'goddess'. This carved figurine appeared to offer belated support for a Palaeolithic origin for flint mining, a view that attracted few supporters by the 1930s. However, although this figurine echoed the style of Palaeolithic carvings, it was greeted with scepticism - as were the Palaeolithic-style etchings found in 1921 - as the weight of evidence argued overwhelmingly for a Neolithic date.
Recently, the authenticity of the figurine has been questioned again, and there are strong grounds for believing that it was made during Armstrong's excavations by persons unknown, probably to deceive Armstrong. Armstrong held firmly to his belief in Palaeolithic mining - but this proved to be his last excavation at Grimes Graves.
Despite the controversy, Armstrong did make notable discoveries - such as considerable evidence for Bronze Age activity - and he also showed that mining had originally covered a much larger area than is represented by the visible earthworks.
More recent excavations by Roger Mercer in 1971-72 on behalf of the Department of the Environment, and then by the British Museum in 1972-76, have ensured that Grimes Graves remains the most widely explored and best known flint mine in England.
One of the questions that needs to be considered about Grimes Graves, and the other English flint mines, is why the miners dug for flint when adequate surface deposits were available in the surrounding countryside. It has been argued that better-quality flint from the deep layers was essential for making big artefacts like axes, but this ignores the fact that during the preceding Mesolithic period, surface or outcropping flint was often used to manufacture large tools such as tranchet axes and 'Thames picks'. Big artefacts did not need mined flint.
The fact that the miners went to a lot of trouble to dig the mines, together with the evidence for ritualised or ceremonial activities, all suggest that mined flint had a special value to Neolithic communities. This value was further enhanced when the flint was crafted into certain types of tools. Many axes, for example, were never used and were returned to the ground individually, in fragments, or in 'hoards', suggesting a ceremonial use rather than a purely functional one.
Despite the Neolithic focus of the site, it is a mistake to think that Grimes Graves was a single-period monument. It has a long history and many other periods are represented. Although very little Early Bronze Age activity is recorded, by the Middle Bronze Age, around 1500-1150 BC, we find an explosion of settlement evidence around the site - but strangely without evidence of houses.
After the mines
Grimes Graves became, at this time, the site of massive midden or rubbish deposits dumped into a number of the Neolithic mine shafts. Over 8,000 Deverel-Rimbury pottery fragments have been found, evidence for metalworking and some six tonnes of worked flint, making this the largest group of artefacts of this date in Britain. Clearly such an accumulation of debris would have taken some time to develop.
The middens also produced evidence of textile production, leather-working, wood-working and pottery manufacture. Animal bones from cattle, sheep/goats, pigs, horse and deer suggest both meat consumption and dairy production. Seeds of wheat and barley were also found, providing evidence of crop cultivation.
Although no contemporary houses have been found, this is not unusual. At Mildenhall Fen, ten miles to the south-west, two similar middens were excavated, again without any evidence for buildings. It may be that Middle Bronze Age houses left little trace for archaeologists to find - or perhaps archaeologists are just looking in the wrong places!
During the Iron Age, people continued to visit Grimes Graves and several excavations have produced pottery sherds, although, again, no settlements have yet been found.
The most significant discoveries came from the upper fills of the mineshaft excavated in 1971 by Roger Mercer, where two inhumation burials were uncovered. These had been buried in sequence - the first a young adult woman with a decorated chalk plaque by her hip; the second, which partly destroyed the first, was an adult male with a necklace or earrings. Both burials appear to have involved ceremonies which included setting fires and placing offerings. It is possible that skeletons found in similar contexts during earlier excavations may also have been Iron Age, and these would then fit the regional tradition for using pre-existing pits for secondary burials.
Although there is little Roman activity at Grimes Graves, pottery sherds have been found, spanning the 1st to the late 4th centuries AD. They represent pots manufactured in Gaul, Spain, Oxfordshire, the Lower Nene Valley and probably East Anglia.
The pagan Anglo-Saxons gave names to both the site and Grimshoe mound on the its eastern edge - Grim's 'Howe' means Grim's, or Woden's, burial mound. This monument also gave its name to the local hundred, the Anglo-Saxon regional administrative unit.
Norfolk's Breckland was the least settled area of East Anglia at the time of the Domesday Book (1086), but from the 12th century onwards numerous rabbit warrens were created in the area. From 1224 Grimes Graves appears to have been owned by Bromehill Priory which probably used the site as a warren. However, by the 16th century Grimes Graves had become a sheep pasture.
A map of 1761 shows not only a very early plan of Grimes Graves, but also in the West Field a number of 'breaklands of the Lord of the Manor', recording typical Breckland temporary fields near the mines. Faint traces of this cultivation can still be seen.
Peter Topping works for English Heritage. He is the author, with Martyn Barber and David Field, of 'The Neolithic Flint Mines of England' (English Heritage, 1999)
CBA web:Jan/Feb 2005