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Cover of British Archaeology

Issue 79

November 2004

Contents

news

Iron Age children's graves found in Orkney

First Anglo-Saxon era papal seal found (and second)

Coastal war defences mean more book borrowing

Casanova's lover knew statue

Roman kiln found - great tiles, poor speller

In Brief

features

Battlefields
Glenn Foard and Tim Sutherland fight for history

Stone tools: the mines
Paul Craddock and Mike Cowell solve an old problem

Stone tools: the men
Paul Sillitoe learns from stone tool users in New Guinea

Viking cemetery
The inside report on a unique excavation

letters

Identity, teaching, pagans, chalk giants and asterisms

 

ISSN 1357-4442

Editor Mike Pitts

features

Cutting Edge

Understanding how flint and other stone tools were made and used offers insights into societies almost unimaginably different from our own. In the first part of a major feature, Paul Craddock and Mike Cowell, British Museum scientists, report on a scientific breakthrough at the 4,000 year old flint mines at Grime’s Graves, Norfolk

Neolithic mines in the north European chalk are amongst the most impressive remains from our industrial past. Vertical shafts up to 10 m or more deep, from which horizontal ‘galleries’ or adits followed flint seams, cluster close together. English mines in Sussex seem mostly to be Early Neolithic (4000-3000 BC), while the Norfolk mines such as Grime’s Graves are often Late Neolithic (3000-2000 BC). Grime’s Graves is one of the largest mine complexes, including the only shaft in Britain that can be descended today.

In Peter Topping’s excellent article on Grime’s Graves (BA September 2003) one important question was not posed: what did the miners actually do with the prodigious quantities of flint?

It was long assumed that primary mine products were axes, and at most mines, especially those on the South Downs, this is likely to be correct. However, at Grime’s Graves the evidence was never wholly convincing. Although many axes and ‘roughouts’, unfinished or failed axes, have been recorded from the site over the years, studies of the knapping debitage (mostly huge amounts of flint flakes) have failed to confirm that any specific artefact was being made.

Many years ago the British Museum undertook a major project to link Neolithic polished flint axes, common in south-east England, to known flint mines by their trace element compositions. Putting it bluntly, the project was not a great success: many axes could not be assigned to a mine. It was suggested they may have come from secondary sources such as clay-with-flints deposits, glacial tills and river gravels. There was insufficient difference in the flint composition between the ten or so mines selected for analysis, for unambiguous assignations to be made for individual artefacts. Grime’s Graves was the only mine with a clear fingerprint, so it was frustrating that only two of over 400 analysed axes assigned to there.

This was actually quite a significant discovery, but its importance was lost in the overall failure to assign axes. Now, some 20 years after reporting what they did not make at Grime’s Graves, we are at last able to identify Late Neolithic artefacts from all over East Anglia that were made from Grime’s Graves floorstone, the most prized layer of flint. This to no small degree is thanks to the field surveys that have taken place in East Anglia through the 1980s and 1990s.

Many prehistoric sites were identified by quantities of struck flint, in particular on the edges of the then recently formed fens. Much of the flint was from secondary sources such as the spreads of glacial material or river gravels. At the Late Neolithic/Early Bronze Age sites there was a new element, black flint that sometimes retained original cortex. This is the soft outer layer that surrounded flint in the chalk, which, it was argued, would be unlikely to survive glacial or river action for long. Furthermore the cortex was rather thick, very similar to that found on the Grime’s Graves floorstone. Thus it was postulated that this new flint was probably coming from primary chalk sources, and in 1991 Frances Healy presciently suggested this could be the elusive Grime’s Graves floorstone.

Some time later we were asked to assess the flint project for the final fascicule of the British Museum’s 1970s Grime’s Graves excavations. This seemed an excellent opportunity to carry out further analyses, this time on samples selected on the appearance of the flint rather than on the artefact type. With Frances Healy and Gillian Varndell, a curator at the British Museum producing the Grime’s Graves reports, we selected a small group of tools and flakes from material obtained by field-walking over many years and now held at the Castle Museum, Norwich.

Flint looks glassy and impervious, but in fact is quite porous. Investigations conducted in the original project showed that the first two millimetres or so were likely to be contaminated by groundwater. Thus to drill an uncontaminated flint core of about 3 or 4 mm diameter the flint has to be at least 2 cm thick over a length of several centimetres. This precludes all but the largest flakes and many core tools and explains why items such as arrowheads and thumb-nail scrapers were excluded from our survey. They may well have been made from Grime’s Graves flint, but unfortunately they are not suitable for this type of analysis.

We selected 15 chunky black flints, many still with cortex in place, including a rather fine polished axe from Lound Run, Belton in Suffolk. From Grime’s Graves itself 13 roughout axes were picked from the many found there over the years, together with two disc knives, also suggested as one of the typical mine products. These were sampled partly to provide a comparative standard with analyses conducted in the previous project, and in the case of the axes to convince ourselves that they really were of Grime’s Graves flint. It was unlikely but not completely impossible that these axes too, like the vast majority of the other East Anglian axes, came from somewhere else. After all, axes of Cornish stone have been found at the site, and marks made by polished flint or stone axes in the chalk underground suggest they were used as mining tools.

The flints were cored with a trepanning drill. Flint is over 99% silica, which is broken down and removed with hydrofluoric acid, followed by dissolution of the remaining elements in perchloric acid. The sample solutions were analysed by inductively coupled plasma atomic emission spectroscopy.

All but one of the Grime’s Graves axes and both of the disc knives were of the same composition as the mine flint previously studied, showing that the new analyses were comparable. The exception was an axe roughout of what appeared to be mined flint, and it is likely to be a compositional outlier. Eleven of the 15 East Anglian artefacts could be assigned to Grime’s Graves with a high degree of probability. Quite literally we had run the elusive floorstone to earth!

In the Late Neolithic many of the old sources of surface flint probably disappeared beneath the growing peat bogs, and additional sources became necessary. Rising sea levels are likely to have caused a movement away from the fen areas to slightly higher land to the east, where floorstone deposits are near the surface. It outcrops at some points on the north-western edge of the mined area at Grime’s Graves: its very superior working properties would soon have been appreciated and the floorstone horizon followed back into the chalk, first with open quarries and then pits and progressively deeper shafts as the depth of the floorstone beneath the surface increased.

A wide range of artefacts, including a polished axe, were assigned to Grime’s Graves, with no evidence that the flint was being used to produce any particular object. Many of the pieces were quite crudely produced: there is certainly no suggestion that flint was reserved for finely made prestige items, as sometimes proposed, and the high attribution rate of the selected items suggests that contra some previous suggestions, Grime’s Graves floorstone was just good flint, freely available in East Anglia. Further analytical programmes are now necessary to identify floorstone in assemblages from other parts of Britain.

Paul Craddock and Mike Cowell work at the Department of Conservation, Documentation and Science, British Museum

The Blade Runners

Anthropologist Paul Sillitoe learnt about stone tool use from Papua New Guinea highlanders in 1983. Here he describes some of the things he saw, and reflects on the implications for prehistoric Britain

New Guinea, the large island north of Australia, was the last place on earth where substantial populations depended on stone tools. Foreigners assumed that the mountainous interior was uninhabited, until in the 1930s gold prospectors and government patrol officers discovered over a million people. They were astonished by dense settlements of squat smoky thatched houses and neat vegetable cultivations along valley sides. These people, using stone tools until modern times, are heirs to a sophisticated horticultural tradition that subsequent archaeological excavations in the Mount Hagen region have proved extend back over 9,000 years, making their ancestors, with Mesopotamians and Mesoamericans, among the first humans to practice farming.

The New Guinea Highlanders’ stone tools fall into two major classes. The most eye catching is the beautiful polished axe mounted on a wooden haft, in some places in use in the mid-20th century, owned and used only by men. The other, the roughly knapped chert flake still used occasionally, has attracted considerably less interest.

The stone axe blade is so similar to that found in Neolithic Europe, if New Guinea and European axes were mixed up in a museum collection it would probably take petrological analysis to distinguish them. Geologically the axes from the New Guinea Highlands comprise thermally metamorphosed basalt, chert and greywacke depending on quarry source. They vary in colour from black through dark blue to green, sometimes veined together, to dark and pale grey. The darker the stone the better quality the blade usually, although colour is not an infallible guide. The people I know test the quality of an axe head – its durability and the time it will hold a sharp edge—by holding it briefly on the palm, then inspecting it for condensation, the wetter blade being superior.

Only a few mountain locations yield stone of axe quality. Several are in the large Wahgi valley basin, where local people took stone from quarries. Sources elsewhere are streambeds, such as along the Jelime and Alokai Rivers. While groups living there had access to valuable raw materials, they did not exploit them fulltime. Men collected stone for blades as they felt like it: there were no axe factories.

Knapping and grinding an axe is a time-consuming and laborious business. It is interesting that no finished polished axes have been found at European quarries such as Langdale, only roughed-out blanks. Likewise in New Guinea persons did not sit and grind out finished tools at the quarries, but put roughed-out pieces into circulation, to be shaped and polished up as exchanged from hand to hand. Grinding required access to abrasive sandstone. To this day, people can take you to sandstone outcrops and boulders with scoop marks, often by watercourses, where their ancestors used to sit honing axe blades.

Men occasionally damaged axes, meaning a visit to a nearby grindstone to hone a nick from the edge. Sometimes disastrously, more extensive damage would demand both knapping and grinding to return an axe to use. Grinding was laborious and monotonous, and the limited blade supply, increasingly an issue with distance from stone sources, prompted men to remove the minimum stone necessary. This often resulted in somewhat lop-sided blades. Within certain limits, so long as the axe had a sharp and usable edge, its shape was all the same to them.

The implications are intriguing for prehistorians, who name entire epochs after stone technologies (Acheulean, Neolithic and so on). In the Highlands of New Guinea some writers have expended much effort in classifying stone axes by shape (for example, noting the angle at which the blade is set or the presence of an edge-facet). When I asked Highlanders about this they laughed, maintaining that all stone blades fall into a single named category. An archaeological typology would belie the users’ conceptions.

Another intriguing issue concerns the geographical movement of axes. Looked at in terms of the archaeological record (ie the distribution of objects after the disappearance of those responsible for putting them there) the dispersal of stone axe blades in the New Guinea Highlands looks surprisingly like that in prehistoric Britain. Some axe blades moved over considerable distances, sometimes hundreds of miles—just as, for example, axes originating in the Lake District have been found in southern England. How did they get there?

We tend to talk of trade, imagining parties visiting regions and buying up axes, or people selling them on from hand to hand. Trade implies purchase and sale in a market-like context, to meet some ill-defined economic need or demand. Our own mercantile cultural background and our experiences of capitalist market-organised society prompt us to think this way. But this is only one interpretation of what our Neolithic ancestors might have been up to.

Ceremonial socio-political transactions are central to lives throughout the New Guinea Highlands. People present wealth to one another at important social events such as marriage, birth and death, and to settle disputes with compensation. Stone axes often changed hands as wealth in these contexts. So we see axes moving in transactions motivated by social and political concerns, not economic and resource ones. It would be ridiculous for me now to suggest on this evidence from a culture on the other side of the world and thousands of years later, that Melanesian ceremonial exchange-like transactions moved stone axes around England. But something like it is a possibility, and just as plausible as trade.

In some parts of the Highlands, notably in west New Guinea, people helved stone axes in Neolithic European style, forcing the blade into a hole made in the head of the haft and securing with hoop-pine resin or rattan. Mostly, however, thanks to a matchless binding material in rattan climbing palm stems, New Guinea axe hafts differ from European ones.

The men I know of the Southern Highlands mounted their blades in split sockets lashed onto wooden hafts using split rattan strands, following an ingenious pattern that became tighter with use, as the stone head was rammed into the socket. It took a man—only men hafted and maintained axes, each attending to his own axe—just over eight-and-a-half hours to haft one for me, working with stone tools throughout. He spent 88% of this time making the haft, socket and strands. However, men more usually rebound axes than made new parts.

Some groups mounted blades as axes, others as adzes. Those I know mounted the head at an acute angle to the haft, generally at 60-70 degrees, with the cutting edge more or less parallel to it. It was invariably some degrees out, the socket twisting around in the binding, for example, or the split in the socket not quite true. Within some 10 degrees or so either way this did not impair the tool’s efficiency. The man who bound up the axe for me was amused at my concern over the blade’s slight angle: from his viewpoint, interest in the precise angle of blades is misplaced.

People had three primary uses for stone axes: felling trees, clearing vegetation to establish cultivations and fashioning stakes for fences to protect gardens from pigs; collecting firewood, again felling trees and cutting up into suitably sized billets; and making artefacts in wood, bamboo and cane, stripping off bark to beat into barkcloth, and so on.

The considerable variety of axe blades related not to specific tasks, but to their scarcity away from stone sources. People could ill afford a specialised range with less than one axe each (all the men I spoke to who had owned stone axes said they had shared them with their fathers when alive and 15% of them subsequently continued to share with a brother). This led to the use of improbably small blades, any damage to which was often critical as axes became scarcely effective.

Nonetheless some axes were clearly better suited to some work than others—for example large axes for felling large trees, smaller ones for finer artefact work – and relatives might lend axes to one another. However, men were possessive of their axes and loaned them reluctantly only to persons they trusted.

As well as physical damage through reckless use, they feared weakening of the axe through improper relations with the other sex. Men believed that contact with a woman could dull an axe’s edge irrevocably, particularly at certain times of the moon. In many cultures throughout the New Guinea Highlands men fear menstruating women, believing that they can cause serious illness, even death (men and women frequently live in separate houses). The weakening association of women extends to not using an axe for two or three days after coitus, one reason that men were chary of lending axes to others!

Imported steel axes and machetes have now replaced stone axes. There has been debate over the impact of this change. It has been said that a stone axe took three to four times longer to complete a task than a steel one, and that in the stone era men spent 80% of their time in subsistence activities, in which axe work features prominently. Steel axes reduced this to 50%, prompting extensive social changes.

These time estimates are probably too generous. In experiments with men working at different tasks, I discovered that in cultivation work and artefact manufacture steel axes proved 1.5 times, and in firewood collection 1.2 times faster than stone. Overall, steel implements were 1.4 times faster. Yet this statistic is of little practical use.

The different activities are not directly comparable. People collect firewood daily, clear a garden perhaps every year or two, build a house every five years and make some artefacts only once in a lifetime, if ever.

Neither is it always feasible to compare the tools directly. Stone and steel axes require different techniques. A stone axe was used with short, rapid pecking blows, putting less weight behind it to reduce the risk of damaging the more fragile head, in contrast to the wider-arching, more powerfully administered chops of a steel axe. Their comparative efficacy varies across tasks. Men use steel axes for work not previously attempted with stone, like felling and splitting enormous hardwood trees.

On top of this, time alone ignores the more efficient exploitation of the environment, and better quality work, facilitated by steel tools. Indeed men will now sometimes spend more time working with a steel axe, because they can obtain a better finish.

Steel tools doubtless led to changes. However, the evidence suggests these were not so dramatic as first thought, stone axes not proving as inefficient as one might imagine. When colonial patrol officers first offered Highlanders steel tools, to their consternation they refused them, demanding instead seashells of the sort they valued highly and used in the socio-political exchanges central to their lives. There are even stories of people pulling pearl buttons off the newcomers’ shirts!

While not as glamorous as the axe, the stone flake has many uses, including shaping, scraping, paring, shaving, smoothing and boring materials such as wood, bark, bamboo, cane, bone, tusk and seashell, and butchering meat.

All men can knap chert blades: they say only men make knives, but if asked will pass skills on to their female kin. They use flint-like and brittle siliceous rocks that fracture with sharp edges akin to a sliver of glass. The process seems rather random, tool-makers striking at a nodule until they obtain a suitable piece, usually after one or two blows. They rarely touch up, and it takes only a few seconds to produce an irregular flake with at least one very sharp edge, although occasionally individuals may mount it in a rough wooden handle.

Sometimes a specific implement like a narrow borer takes longer, requiring several blows to obtain the right flake. It may take 15 minutes or so to obtain the flake, mount it in the split end of a stick and roughly bind it with suitable vine or bark fibre strand to hand.

It is largely men who use chert knives, although occasionally women will, for instance to smooth the handles of their digging sticks. Although they have surprisingly sharp cutting edges when freshly knapped, flake tools soon become dull. People make new ones as needed, for raw materials are plentiful and no one exercises exclusive rights to sources such as streambeds. In addition to a chert nodule, a man requires a hammerstone, such as a piece of hard basalt, pieces of which are often littered around homesteads where they are used for cooking in earth ovens. Occasionally individuals keep a good tool for use again, but they are small and easily lost. They dispose of used tools and debitage carefully, out of the way of bare feet, or, in the case of unused pieces and sizeable cores, where they may find them again.

The versatile little flake is an integral part of the Highlander tool-kit. While stone axes carried a considerable exchange value (large ones could change hands for a pig), flake implements readily made from materials that are in good supply are not traded. Even with the advent of steel tools flaked blades remain in use, if somewhat less so than previously, for they have extremely sharp edges and can be selected according to size and shape for particular tasks.

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