Читать книгу A Book of Britain: The Lore, Landscape and Heritage of a Treasured Countryside - Johnny Scott - Страница 9

The exertion that went into digging out hill carvings pales into insignificance when compared with some of the other creations that display an extraordinary commitment of time and effort for no apparent purpose. Silbury Hill near Avesbury, in Wiltshire, is the tallest prehistoric, human-made mound in Europe and one of the largest in the world – similar in size to some of the smaller Egyptian pyramids of the Giza Necropolis. Composed mainly of chalk and clay excavated from the surrounding area, the mound stands 40 metres high and covers about two hectares. It is an exhibition of immense technical skill and prolonged control over labour and resources. Archaeologists calculate that Silbury Hill was built nearly 5,000 years ago and took 18 million man-hours, or 5,000 men working flat out for fifteen years to deposit and shape 250,000 cubic metres of material. This incredible structure contains absolutely nothing; no burial chamber of a great tribal chief and not one iota of treasure. It was a huge disappointment to the first Duke of Northumberland, who employed an army of Cornish miners to burrow their way through the hill in 1766, convinced they would find him some loot. There is no explanation why anyone should want to build Silbury Hill, apart from the indisputable fact that it looks jolly impressive in the middle of an otherwise flat piece of ground.

Equally peculiar are the inexplicable earthworks known variously as black-dykes, devil’s dykes or Grim’s dykes, found from the south of England right up into southern Scotland. These consist of a ditch and mound of varying dimensions which follow a winding course across country, often traceable for miles. The great trench and mound of the Devil’s Dyke in Cambridgeshire and the long line of Offa’s Dyke on the Welsh Marches are two of the most well known. The Devil’s Dyke runs for 12 kilometres from the flat farmland of Reach, past Newmarket to the wooded hills around Woodditton, periodically reaching a height of II metres. Offa’s Dyke is the massive 200-kilometre linear earthwork, 20 metres wide and about 3 high, which roughly follows part of the current border between England and Wales. There are several other remains of earth banking: Grim’s Ditch in Harrow; the Black Ditches at Cavenham in Suffolk; the Brent, Bran and Fleam Ditches in Cambridge; and Woden’s Dyke in Wiltshire. In southern Scotland we have the Catrail, which meanders 22 kilometres from Roberts Linn, just up from the farm, to Hoscote Burn in south-western Roxburghshire. The 8-kilometre Picts Work Ditch, from Linglie Hill to Mossilee, near Galashiels and the Celtic Dyke in Nithsdale, Dumfriesshire, runs for about 27 kilometres parallel with the River Nith between New Cumnock and Enterkinfoot.

Scottish ‘black dykes’ are small compared to the others, being about two and a half metres at the base. Most of these earthworks appear to have been constructed in the early Anglo-Saxon period and all, even Offa’s Dyke, share one thing in common: for all the labour and energy that must have gone into building them, they serve no recognisable function. They are demonstrably not defensive; in most cases they are so short that an enemy would simply nip round the sides or, in the case of Offa’s Dyke, it would be impossible to man the entire length effectively. They are obviously not boundaries, and a theory popular among nineteenth-century Scottish historians, that they were built to hinder neighbouring tribes escaping with stolen livestock, was quickly discredited. The sort of semi-wild farm animals that were around in those days would easily have been driven through the wide ditch and up the slope of the earthwork.

I find it absolutely delightful that these ancient earthworks have completely stumped the theorists and not even the silliest neo-pagan can claim them as some sort of fertility symbol. So why were they built? In the absence of any other explanation, I presume the motive was similar to that which gave us Silbury Hill; someone must simply have woken up one morning and thought a big earth dyke in this or that location would improve the look of the landscape.