Dig Diary – Monday, August 22, 2016

Day Thirty-Six

An unexpected discovery

The cache of hammerstones related to Structure Twenty-Eight under Structure Twelve.

The cache of hammerstones related to Structure Twenty-Eight under Structure Twelve.

The sky over the Ness today was grey and overcast and so, unfortunately, was the mood down below.

It’s partly a hangover (non-alcoholic) from the frantic endeavours of the second open day, yesterday, and partly a realisation that everything is winding down gently in what is our last week on site.

The archaeology, however, continues to surprise.

In Structure Twelve, Paul has been recording, and finishing off, a sondage at the south end.

This has taken him into a sequence of floor deposits and more of the wall of Structure Twenty-Eight, which is an earlier incarnation of Structure Twelve.

More spreads of pot from outside Structure Twelve.

More spreads of pot from outside Structure Twelve.

Within part of the wall core, he uncovered a group of hammerstones and stone chips, reinforcing the impression that Structure Twelve, and its predecessor, was obsessed with hammerstones.

Structure Twelve’s other obsession is pottery and more large sherds were turning up outside the blocked-up entrance at the south end and all the way around that southern sector.

Not far away, Claire and her team have continued to expose Structure Twenty-Six, which lies to the south of Structure Ten.

Rubble infill of Structure Twenty-Six is gradually removed.

Rubble infill of Structure Twenty-Six is gradually removed.

Walling is still emerging and there were hopes that it would have a gentle curve. Instead, we have some decidedly angular walling, with the interior of the structure full of very large rubble.

The saving grace thus far is that some of the rubble stone is beautifully decorated – indeed Claire has already uncovered two separate stones decorated on the edge and top surface which join together.

Unfortunately for Claire, one of the stones has lost some surface to delamination and her efforts in washing and carefully examining all the shaley stones in the trench have failed to turn up what should be the missing pieces.

The piece of wood discovered by Jenny within the gunge in the north-western corner of Structure Ten.

The piece of wood discovered by Jenny within the gunge in the north-western corner of Structure Ten.

We told you a couple of days ago of the remarkable survival of organic material in the north-eastern area of Structure Ten.

This comprised some peculiar green gunny material, which is suspected to be unburnt seaweed.

Why this has survived over thousands of years is something of a mystery.

The conditions in which it was found are, indeed, unusual, comprising a slab of stone over the top and everything on a gentle slope, which admitted water, but not enough to wash anything away.

As Mark (Beep One) commented, the fact that some has survived may point to other favourable conditions for survival further down, so we may have more surprises to come.

We certainly had one today, because, as Jenny worked through some of the gunge, she discovered a substantial piece of wood.

It was buried in the material, but the end could be seen clearly and it seems as if the wood may have been deliberately split.

To find that wood has been worked suggests that it may turn out to be a wooden tool of some sort. Careful excavation and subsequent conservation will continue, but this totally unexpected discovery has certainly been one of the highlights of excavation this season.

Wulfric tirelessy barrows the sandbags to the trench edge, ready for placement within the buildings.

Wulfric tirelessy barrows the sandbags to the trench edge, ready for placement within the buildings.

Lastly, we have been joined on site by Wulfric, who comes from Sanday, one of Orkney’s North Isles.

He is taking part in the Duke of Edinburgh’s scheme and has been making himself extremely useful today with the hard and mundane task of shifting sand bags.

These are being pre-positioned around the site so that when the time comes (probably Wednesday) to start covering the site over with black plastic, the bags will be ready to support delicate structures and to hold down the plastic.

The other main element which holds the plastic in place during the fierce winter winds is tyres. Wulfric will soon be learning the ancient Neolithic sport of tyre-rolling.

We’ll be back tomorrow

By the way, if anyone fancies getting a bit of physical exercise on Thursday and Friday this week, why not come along and help with the annual recovering of the site – if you are reasonably fit just turn up at 9am in some old dirty clothes and bring your lunch and gloves – a vital part of the Ness operations as Jo Bourne describes below.

From the Trenches

Structure Eight: Dirty Work

Jo, Alice and Chloë getting ready to cover Trench T in 2014.

Jo, Alice and Chloë getting ready to cover Trench T in 2014.

In just a few days the trenches and excavated buildings at the Ness of Brodgar will be covered in around 4,000 square metres of black plastic tarpaulins, plus sandbags and tyres.

The site will resemble an art installation-come-massive farm midden and visitors won’t see anything of the archaeology until the wraps come off again in July next year.

It takes two valuable days, and a lot of extra help from generous local people, to shore up the walls and sections, scoop the tarps from behind the spoil heap, roll the tyres to the trench edges and place them on top. Plus it’s dirty work.

So why do we do it?

Chloë making use of every last scrap of tarp.

Chloë making use of every last scrap of tarp.

First and most obviously, we do it to protect the archaeology.

Orkney has some spectacular storms in the autumn and winter.

The kind of winds that blew the sand from Skara Brae in 1850, revealing its presence to the world, could blow the tops off the walls of the Ness and scatter the stones as far as the lochs.

The remains of our 5,000-year-old buildings could be destroyed in a matter of hours. What survives here is far too precious to be left at the mercy of the elements.

Even if Orkney were to experience the most clement winter, we couldn’t leave the site uncovered.

Getting wet in the cover-up, 2014.

Getting wet in the cover-up, 2014.

“Solid as a rock” really doesn’t apply here. The buildings of the Ness are constructed with sedimentary rock – Devonian flags made of mudstone and siltsone together with sandstone blocks, all around 400 million years old.

While some of the stones look almost freshly quarried, others are more vulnerable to heat, moisture and frost.

There is a huge variation in their quality across the site, with Martha the geologist referring to some as “wet phonebook” rocks, which are more akin to millefeulle pastries than building stone. These need every bit of protection they can get.

Structure 1: The precious rocks used in the buildings need protection over the winter.

Structure One: The precious rocks used in the buildings need protection over the winter.

Then there is the wildlife issue.

Nature abounds in Orkney and we frequently come back to an uncovered structure to find small presents from the birds that have flown over.

Plants grow from windblown seeds in just a few weeks.

Plants grow from windblown seeds in just a few weeks.

More serious is the plant life. In just a few weeks, clean sections develop a green tinge as moss begins to form, and small plants take root and burst into leaf.

While nature is wonderful, it’s not good for the archaeology.

Roots spread and crack rocks, and weeds mask critical features that help us to understand the site’s form and function.

Were the Ness to be left open, it would take us more than two days to clean and weed.

So the tarps, tyres and sandbags go on to protect the Ness from wind, rain, sunshine and freezing conditions, and to keep it pristine for further study.

So while there is limited opportunity to see the site, putting it so sleep for winter will keep it safe for decades to come and enable us to discover, and reveal, so much more.

Jo Bourne

The north end of Structure Eight gets covered.

The north end of Structure Eight gets covered.