Spent the day moving down through the cairn to a maximum depth of about a metre below the barrow's surface. The empty spaces under the stones have been hard to get a grip on as they contain no recognisable nest material and keep getting filled up with spoil dirt and disappearing as we dig. One did seem tubular in shape. But we cleaned stones, photographed them, removed them and repeated this three times before reaching the bottom of the cairn. And there, in the openings between the stones, we struck what looks like a thick and extensive layer of charcoal.
I won't call it a cremation layer, because we have no bones or burnt artefacts. But judging from what 1st Millennium barrows are usually like, we've probably hit the periphery of a huge pyre layer in which the bones may be concentrated to the centre. And Bronze Age barrows contain no cremation layers at all. So from a typological point of view we've already dated the barrow. Cremation layer equals late 1st Millennium. And as for radiocarbon, we have bags and bags of charcoal in big nice chunks from a safely sealed context: the charcoal layer under the cairn.
I was expecting to dig through featureless soil on the barrow's periphery until we hit the natural beneath it, in which, if we were lucky, we might find something organic to give us the earliest possible date for the barrow (terminus post quem). Instead we've encountered huge amounts of organics that are clearly part of the barrow itself and cannot be redeposited earlier material. So we've been very lucky given the question we're here to answer: when did someone invest a huge amount of labour into building the barrow?
So we're pretty much done. What remains to do now is draw the sections, seed the trench floor with fresh coins as our signature and backfill the trench. We have no real reason to try to punch through the charcoal layer to measure its thickness and retrieve material from under it, because it is clear that the charcoal is contemporary with the building of the barrow and so will date it. Also, neither ourselves nor the county archaeologist want the burial disturbed. Future colleagues who excavate the entire barrow one day won't thank us if a 2.5 by 1.5 meter patch of the finds layer is missing.
After the day's work we've had a microwave dinner and watched the South Park guys' irreverent puppet movie Team America. Good fun, pretty much taking the mick out of everyone, as my British friends say.