The sarsens of Salisbury Plain – A conversation with David Field | Armchair prehistory:
Excerpts from David Field's emails.
... There are, however, quite a few smaller sarsens around on Salisbury Plain and some were indeed incorporated into long barrows. Knook Barrow had a cairn of sarsen, Arn Hill long barrow had a standing stone, Corton long barrow had a ‘massive boulder’. Cunnington said that sarsens can be found all over the downs beneath the turf and that farmers plough them up in the area north of Stonehenge (Larkhill west of barracks) from time to time. There is a long barrow there (Figheledean 31-see attached) with three in the ditch and another six in a line where they were disturbed when the military built a rifle range. Quite a few around Bulford, aside from the Cuckoo stone (attached), Togstone and the one in the river, there is one from a round barrow that had a burial beneath an ‘immense sarsen’ and a number of others noted on early maps. One of the King Barrows formerly had a sarsen circle or kerb around it. Today the Imber to Chittern valley has many small boulders and cobbles on the
slopes and in the stream and presumably many more were once visible when the area was cultivated.
As you rightly say, none of these are large in trilithon terms, but then neither are any of those on the Marlborough Downs where they rarely exceed a couple of metres – three at the most. The big ones there seem to have been reserved for the Cove and blocking stones at West Kennet. The survival of many on the Marlborough Downs can be put down to lack of agriculture (it’s a degree colder there than Salisbury Plain) for they get in the way of ploughs and soon get cleared and broken up or buried. You can trace the clearance process at Overton/Fyfield from undisturbed sarsens on the summits, to the clearance to field edges to create ‘Celtic’ Fields in the Bronze Age on the upper slopes, to the development of lyncheted fields that cover the sarsens around the edge in the Roman and medieval periods on the lower slopes. If the same processes took place on Salisbury Plain where there was widespread agriculture in Roman, medieval and post-medieval times there will be many other sarsens buried beneath the field lynchets.
So where did the big ones come from?”
I think that regarding statistical pattern of distribution based on size frequency the Marlborough Downs would have it as there are so few around Stonehenge. But the difference between a three metre and five metre sarsen is quite dramatic and I imagine that just one in either place could shift the balance. Its perhaps worth noting, though, that the heelstone is not exactly small and because of its shape few people will argue that it was brought from far.
Heavy mineral and grain size analysis carried out in the 80s on some of the Stonehenge sarsen indicated that it did not match samples from Clatford Bottom and Piggledene on the Marlborough Downs. Not that this really demonstrates much as sandstones can differ in composition quite dramatically over relatively short distances, except to perhaps note that, for the moment, it provides no support for the idea of a Marlborough Downs origin....
Edward Pegler's blog also has an interesting argument about the origin of the Bluestones, and the water at Avebury, as well as lots of other stuff!