“Midden” is a blanket archaeological term that refers to rubbish, debris or other by-products of human activity. For archaeologists, these deposits provide a vital link to the past. If you want to know how someone lived, look at their rubbish.
But before we dismiss “midden” as just dumped refuse, the situation is slightly more complex than that. Firstly, there is no single midden substance – it obviously varies in composition depending on the historical period, location and the activities carried out in the area. For that reason many archaeologists don’t like the term “midden” and the baggage it carries. Suggested replacements include “anthropic sediments”  or “occupation deposits” .
Medieval coastal middens, for example, might contain shell and sand, while the midden at the Ness of Brodgar includes, among other things, pottery fragments, ash, burnt bone and clay.
But for the purpose of this post, and to keep things simple, we’ll stick to midden.
In addition, prehistoric midden deposits may have had – or gradually developed – a significance that went beyond just rubbish. In the Mesolithic, huge shell middens may have started their long lives as dumps but over time, as more material accumulated on and around them, so did their significance.
These highly visible mounds may have come to act as markers, or memorials – a role that may explain the deposition of human remains in some .
In Neolithic Orkney midden was not only used as a fertiliser but became part of the construction and the architecture of certain buildings.
In addition, and as exemplified at the Ness of Brodgar, it seems to have become a sign of conspicuous consumption. The more extravagant your lifestyle the more rubbish you produce. Leave that for people to see and your status is clear to all.
What can midden tell us?
Although midden deposits can tell us what people were eating, they can also show what they were not.
At the Ness of Brodgar, for example, a lack of evidence suggests that seafood was not on the menu. Recording variations in the refuse deposited over time can also give an indication of dietary changes.
The composition and volume of midden deposits associated with a particular structure or area can help paint a picture of activities that took place and allow comparisons to be made.
Midden can also trap evidence of environmental events such as sandblows, as well as pollen and insects, while charcoal and other organic material can be radiocarbon dated.
Midden at the Ness
The late Neolithic midden in Orkney: decay, assemblages and the efficacy of unwanted things.
The creation and use of midden material was a major part of life in Neolithic Orkney.
There is no doubt that it was used to enrich soils and, in some cases, midden mounds became the sites of cultivation themselves.
By the Late Neolithic the use of midden material extended into construction, and it was used as wall core in certain structures. This was the case with the Ness of Brodgar piered buildings but not found in earlier structures. This new reliance on midden may explain why we find new structures being built close to, or cut into, existing midden spreads.
While there were practical reasons for using midden in construction – supporting the walls and acting as insulation – there may also have been a deeper significance.
This may lie in the nature of midden itself. A by-product of daily life it can be argued to represent a link to the past, and perhaps more specifically events of the past.
As anyone who has visited the Ness of Brodgar will know, the structures were built on the sites of their predecessors – something that has been interpreted as maintaining a link to those who went before.
In addition, as Downes and Richards point out: “[The] merging of decaying vegetable and organic matter, with ash, bones, flesh, stone and clay, and manure, was generative in the sense that a new substance emerged; a substance that had vital and productive qualities and potentialities” 
The switch to using this “new” substance in wall cores, rather than rubble, may have been more than a practical choice. Was midden’s inclusion into the fabric of a structure regarded as incorporating a physical symbol of the past, life and fertility?
To Downes and Richards, the evidence suggests that, by the Late Neolithic, midden material “can be recognised as transcending a role of mere house insulation.” 
It is notable that midden is not used in the construction of chambered cairns – structures with a firm association with the dead.
The later Ness of Brodgar structures not only contained midden in their architecture but were surrounded by it. Like other Neolithic settlement sites across Orkney, midden was constantly accumulating outside the buildings over their lifetimes.
A poor decision?
The ever-growing midden dumps provided the material to create level surfaces ahead of building construction. As we know this process was problematic and inevitably led to structural problems in the new buildings. In most cases, Structure Twelve for example, they collapsed as the midden platform settled around the remains of earlier buildings.
People in Neolithic Orkney had been building in stone for centuries before the Ness of Brodgar piered structures were raised. Surely they must have recognised that using midden was a poor foundation? Was its use just a mistake? Did longevity not matter to them? Or was the use of midden a deliberate choice for reasons we can’t fathom today?
It is also worth noting that after they were abandoned, the remains of the Ness buildings were buried by tonnes of midden, rubble and soil, hiding them from view.
Covering a 30-metre-square area, the “central midden area” was the name given to a huge midden spread overlying the central paved area in Trench P. This midden began to accumulate after the occupation of the surrounding structures, when their rubbish was dumped on the paving outside.
As the volume of midden increased, the area became a place to deposit more than just refuse. The presence of polished stone artefacts within the layers of midden suggests the central area was considered suitable for the burial of the very fine objects at the end of their “lives”. 
Once a focus of the complex, around the time Structure Ten was constructed, the central paved area was quickly, and completely, buried in a mix of rubble and midden. Presumably the new building had become the focus of the site.
Throughout the life of the Ness complex midden accumulated around the buildings. While there may have been episodes where some of it was carried off to the growing midden mound to the south-east, activity at the Ness, as elsewhere, was accompanied by the deposition of midden.
As the buildings began to fall out of use, they too began to fll with midden, until eventually they were deliberately, and entirely, filled and covered over.
Near the south-eastern tip of the Ness of Brodgar is another huge mound of midden.
With a diameter of c70 metres (230ft) and at least four metres (13ft) deep, this mound is still visible for miles around. In its heyday, however, it must have been as imposing as the monumental structures that stood to the north-west.
The mound was “…the result of depositing monumental quantities of occupation refuse. The overall scale of these deposits is staggering but already it is clear that we are looking at the accumulation of material over an extended (perhaps phased) period; a long and complex sequence of episodes and events.” 
Lying beneath this mound are the remains of a building – Structure Twenty-Seven. While there is still much to learn about Twenty-Seven, what we do know is that it was dismantled in prehistory and gradually, and deliberately, covered in tonnes of refuse and ash.
As we’ve seen, other buildings at the Ness were covered in midden after abandonment. The process of burying a “dead” building not only removed it from view but perhaps “contained” in – preventing people getting in and perhaps anything else from getting out.
At the same time, the huge accumulations of midden made the site of the former buildings stand out – monumentalising them.
Downes and Richards suggest: “As the organisation of settlement became more fragmented towards the end of the third millennium cal BC, so the substance and permanence of the great midden mounds becomes more important, not only is midden material dumped on the mounds but occasionally burials are inserted into partially filled houses.
“Consequently, the substantial and enormous mounds comprising late Neolithic settlements, such as Bay of Stove, Sanday, or Muckquoy, Redland, Mainland, were monuments to dwelling and emblems of continuity and identity.” 
The Ness mound is made up of dumped refuse – primarily peat ash and and burnt bone that presumably came from the complex itself. On current evidence it seems the mound began life as a series of smaller midden heaps that gradually merged and continued to grow.
It probably reached its current scale late in the life of the Ness complex, around which time we see its surface used for the careful and deliberate deposition of artefacts.
In one example, a layer of clay was laid over the surface of the midden and animal bone (including whale) and the skull of an aurochs (or very large bovine) laid on top. This was covered by a “new” midden deposit and pottery sherds spread across the surface. 
Similar deposits have been recorded across the mound suggesting that, in its later life at least, it was more than just a rubbish dump – assuming, of course, it was ever regarded as such.
At present, the size of the midden mound has no parallel in Orkney. Although similar examples can be found elsewhere in Britain, these tend to be Bronze or Iron Age in date and associated with episodes of large-scale consumption.
From what we know about the Ness of Brodgar, it may be the midden mound was similar – a monument to the feasting and conspicuous consumption that occurred on site and a highly visible symbol of the affluence and status of those involved.
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