Friday, October 20, 2006

Mysterious Stones Beneath Bourne Hill

As anyone who's ever read 'The Wyre Archaeology Omnibus' and 'The Legacy of Bourne' will already know, in 2005 Wyre Archaeology tracked down and partially excavated an Iron Age settlement, dating to the 2nd Century, at Bourne on the outskirts of Thornton. It has to be said that, during our excavations, one of the biggest enigmas we encountered was discovered in our extension to Trench 012; Trench 012 being the trench in which the fragment of Roman mortarium pictured below was discovered lying on a red clay floor.

The trench’s subsequent extension proved problematic, our original theory that we might have hit upon an Iron Age kiln giving way to the discovery of three postholes, the centre one of which appeared to be banked by orange clay.

Studying our previous reports again whilst downing several large glasses of whisky for inspiration, we decided to open Trench 017, incorporating the northeast corner of Trench 012 and, by way of consequence, one of the aforementioned postholes.
As expected we soon hit the layer of red clay found in the previous trench…the clay on which our mortarium fragment had been sitting. At the same depth, however, we also struck something solid which, as it emerged, turned out to be a brick-shaped lump of granite. Naturally intrigued we dug around it, soon striking a second water-washed stone of substantial size. The larger of these stones measured 25 centimetres in length by 17 centimetres in width. Both were firmly embedded in the orange clay.
All of which was very exciting but, true to the nature of such discoveries, we had no idea what they actually were…other than large, water-washed stones of course. In fact, our best guesses at the time included the corner of a wall or a hearth surround…but as the stones didn’t appear to extend anywhere and as there were no signs of burning (other than a few scraps of charcoal) in the area, these theories didn’t carry much weight.
On Saturday the fifteenth of October 2005 we returned to Bourne Hill and extended Trench 017 to the north, adding approximately 20 centimetres to its width and uncovering in the process more large stones.
Now we noticed that they had been deliberately laid out, as can be seen in the photograph below, three of them forming the sides of an almost perfect square...give or take the odd nick.

As both the gap between these stones and the length of the ‘brick-shaped’ stone seen on the left of the photograph measured exactly 20 centimetres, it’s easy to speculate that the ‘brick-shaped’ stone might originally have completed the square. One large and seemingly incongruous piece of cinder or slag emerged from the centre of this ‘structure’.
Several fragments of ‘heat shattered’ conglomerates and sandstone were also unearthed around it.
The following day, extending the trench even further, at the usual depth we struck a layer of extremely hard red clay. Embedded in this clay were (from top to bottom) tiny stones no bigger than gravel, followed by pebbles and, finally, larger stones measuring several centimetres across. These seemed to us to be forming a floor…although that might, in all honesty, just have been wishful thinking. Beyond the red clay to the south stood the larger stones mentioned above. Broken stones, a few centimetres in diameter, appeared to have been packed around these. The larger stones themselves all had flat bases with diagonal grooves running across them.
Two of the ‘packing’ stones had right-angled sections removed from them, reminding us of the other right-angled pebbles discovered in Trench 012 (shown in the scan below) although, of course, we’ve still no idea what they are.

Despite the red clay being difficult to dig through, we continued until satisfied that nothing else lay beneath it. Worth mentioning, however, is the fact that the large water-washed stones forming the square all appeared to be speckled with some sort of black substance.
To the west of Trench 017 we opened up a test pit to determine whether the red clay, the smaller stones or the larger stones extended in that direction. Having reached a depth of 56 centimetres only to discover that it contained nothing but soil, we made the assumption that they obviously didn’t.
Still none the wiser about what we were excavating, we drew up the trench using our latest acquisition (i.e. a drawing frame), covered it with a board, surrounded it by gateposts (which, incidentally, the cows seemed to appreciate) and retired.
To date the mystery remains unsolved. Whatever the stones are they’re certainly of the Roman period…so, if there are any experts out there reading this who might have a theory, please let us know. In the meantime we'll just have to wait until the digging season returns before we can continue our investigation.


John said...

How fortunate you were to find charcoal fragments! Did you send them out for Carbon analysis, to date the site? That would be really helpful, and supportive of your argument if the dates match.

Also, I believe that right angled breaks in stone indicate heat damage from being in a fire. Here in the states, we look for right angle cracks in stone to find Native American settlements, since fires were integral in the cold north.

The hard clay may have been a packed floor, and the stones the hearth, and the post holes of course being the posts that supported a most-likely wooden frame of a building. All together sounds like a stone age building, much like the old Native Longhouses we have here in the Northeast US.

What's a mortarium? A funeral urn?

Whatever it is, it's quite possible that the Romans used an already existing structure for their own purposes, which is very common in your country.

It looks like you have a lot of work ahead of you. You should try to establish the size of the existing building, and then look for traces of others. Somewhere in the middle may be a common area where you might find a larger hearth, or other working areas. Of course, you don't want to place preconceptions on a dig site, but sometimes it helps to have a starting place.

Good luck, and please keep us informed of future progress!

Cheers, JOHN :0)

Brian Hughes said...


Unfortunately carbon-dating costs a fortune but, on the up-side, we can date the site from the fragment of mortarium (which, incidentally, is a shallow bowl used in a similar fashion to a pestal and mortar for grinding fish heads etc): i.e. second century.

The building itself is most definitely round (making it Celtic rather than Roman) and measures (if memory serves) about forty-odd feet across (again, making it late Iron Age rather than Neolithic or Bronze Age; roundhouses from these earlier periods being of smaller size).

Whilst the second century is associated with the Roman occupation it doesn't naturally follow that the inhabitants of our settlement were fully romanised. The mortarium, however, was a roman invention proving, if nothing else, that there was a Roman influence here (if not architecturally then certainly in the inhabitants' domestic ware).

Your suggestion about the right-angled stones is fascinating and one that I've never heard of before. There were no signs of burning in the areas where they were discovered, but they might well have been heated elsewhere on the site for use as packing stones.

You're absolutely right, of course, we do have a long way to go, and hopefully in 2007 we'll be getting hold of a JCB to help the job along.

Always remembering that these articles tend to be reproductions from newsletters written last year there's a good chance we've already written more about this subject somewhere else, but it hasn't found its way to the blogger board yet. Needless to say, we'll keep you posted.