Why Dig Fifteen Metres for Stone Lying on the Surface? Better Stone Underground
By the BrainSnail editorial team. How these articles are written and checked, and how to tell us when one is wrong.
Neolithic communities sank shafts through chalk and drove galleries sideways to reach particular seams of flint, ignoring the flint available at the surface. The effort involved says a great deal about what they were doing.
Why the surface material was not good enough
Flint occurs in chalk as nodules and it also occurs scattered across the surface where the chalk has weathered away, so material was available without digging at all. That surface material is inferior in a specific way, having been exposed to frost, heat and wear for a long time, which produces internal cracks that cause a nodule to shatter unpredictably when struck. Flint taken fresh from a seam still holds the moisture it formed with, is free of those cracks and fractures in a controlled and predictable way, which is exactly what a knapper needs. Particular seams were also recognised as producing material of a distinctive colour and quality, and those seams were followed specifically.
How the mines were worked
The engineering is more accomplished than the date suggests:
- •Vertical shafts sunk through overburden and chalk, reaching over fifteen metres
- •Galleries driven horizontally along the seam from the shaft bottom
- •Antler picks used to lever nodules out, worn and discarded at the face
- •Pillars of chalk left standing to support the roof
- •Spoil from new shafts backfilled into exhausted ones
- •Lamps burning animal fat, and tallies or marks left on the walls
What the sites look like
Major complexes cover substantial areas and are conspicuous once recognised. The best known in Britain covers around fourteen hectares and contains the remains of several hundred shafts, appearing at the surface as a field of shallow hollows where backfilled shafts have settled. Comparable complexes exist across northern Europe, including extensive sites in Belgium, Poland and the Netherlands. Excavation reveals the galleries intact, with the marks of antler picks still visible on the chalk faces and picks left where they were dropped, which is why the sites supply unusually direct evidence about technique. Radiocarbon dating of those antlers places the main period of working in the fourth and third millennia before the common era.
What was made from it
The product of the mines was principally the polished axe, and understanding what those were for explains the investment. A rough blade was struck out at the mine and carried away for finishing elsewhere, and finishing meant grinding and polishing the surface over many hours against a stone with sand and water, which produces a smooth blade. Polishing improves performance measurably, since a smooth surface meets less resistance in wood and a smooth edge resists chipping, and experimental work has confirmed both. It also produces a conspicuously fine object, and a substantial proportion of surviving examples are unused, made from unusual stone, or deposited in rivers and bogs, which indicates a value well beyond cutting timber.
What the effort tells us
The labour involved is the striking fact and it has been estimated in detail. Sinking one deep shaft and working its galleries required a substantial group working for weeks, moving many tonnes of chalk with antler and bone, in conditions that were dark, cramped and dangerous. That effort produced a material that was available, in poorer quality, from the surface at no cost. Explanations therefore look beyond simple utility, and the leading ones involve the value attached to material from a particular place, the social importance of the act of extraction, and the role of the resulting axes in exchange networks that moved them hundreds of kilometres. Stone from these sites travelled far beyond where it was needed, which supports that reading.
The takeaway
Surface flint has been cracked by frost and weathering and shatters unpredictably, while material from a seam is fresh and fractures controllably, which is why shafts were sunk over fifteen metres and galleries driven along particular seams. Antler picks, chalk pillars and backfilled shafts are the standard evidence. The labour far exceeded what utility required, and the products travelled hundreds of kilometres through exchange networks.