In 1850 a storm removed the turf and sand from a big mound on the shore of the Bay of Skaill in Mainland Orkney and revealed the remains of stone houses. The buildings date from the late Neolithic and the settlement was inhabited for around 600 years between 3200BC and 2200BC. Eight dwellings survive and they are linked by low, covered passages. The site is very significant and has been described as one of the most important Neolithic sites in Western Europe, and designated as part of The Heart of Neolithic Orkney World Heritage Site by UNESCO.
The well-preserved remains at Skara Brae are situated in the dunes at the top of Skaill Bay. Their position was originally some distance from the beach but coastal processes have now placed them in a vulnerable position right on the eroding edge of the land. A protecting wall has been built to prevent further destruction from the sea. To the immediate north of the archaeological site the shoreline has continued to be cut back to a noticeable degree in contrast to the protected area of the Neolithic settlement (see image 6). The site is built upon and embedded in unconsolidated sediments, including midden refuse with seashells.
The buildings sit on top of what might be termed more recent geological deposits, not on top of the solid local Devonian flagstones that can be seen outcropping on the beach below. This beach has a complex history reflecting sea-level rise and the landward advance of dune systems (Vega Leinert et al., 2000). Ponds formed in glacial sediments dumped by melting ice sheets on top of bedrock around 6550 years ago. We know from pollen in core samples that trees like beech, hazel, and willow were dominant in woodland with undergrowth around the ponds, and Phragmites reeds indicate a freshwater marsh environment. The ponds filled up with organic sediments derived from decaying plants and including pollen. A peat bog was formed. Eventually the whole area became smothered by windblown sand from a dune ridge system migrating towards the land from the west from about 6120 yr BP. A subsequent sea-level rise drowned the area. Parts of these peat beds can now be seen in the intertidal zone beneath the boulders and cobbles but above the bedrock of Devonian flagstones. It is possible to see large pieces of preserved wood and other plant remains in the peat. The peat bed continues landwards beneath the pebble bank at the top of shore, and beneath the stabilised sand dunes in which the settlement was buried. The difficulties of living in an area constantly affected by wind-blown sand was no doubt a contributory factor in the ultimate abandonment of the settlement.