Prehistoric Scotland

The final collision occurred during the Devonian period, with the Scottish segment of the Laurentian plate smashing into Avalonia (which contained what is now most of England and Wales), a motile subcontinent which had previously joined with Baltica.

This tectonic activity produced the basis of Scotland's topography: ancient mountains in the North and South of the country, partially eroded by 400 million years of water and ice with a wide fertile valley between them, and a newer, wilder western terrain.

With Scotland now in the northern temperate zone, it was subjected to numerous glaciations in the Neogene and Quaternary periods, the ice sheets and their attendant glaciers carving the landscape into a typical postglacial one, overdeepening river valleys into the characteristic U-shape and leaving the upland areas covered with glacial corries and dramatic pyramidal peaks.

In lowland areas the ice deposited rich fields of fertile glacial till and eroded the softer material surrounding the extinct volcanoes (particularly the older Carboniferous ones), leaving many crags.

Repeated glaciations, which covered the entire land mass of modern Scotland, may have destroyed traces of human habitation that existed before the Mesolithic period.

This is the first and so far the only evidence of Upper Paleolithic human habitation in Scotland, around 12,000 BC, which appears to fall between the Younger Dryas and Lomond Stadial periods when cold conditions returned relatively briefly.

Finds of flint tools on Ben Lawers and at Glen Dee (a mountain pass through the Cairngorms) show that these people were capable of travelling well inland across the hills.

[5] The remainder of this section focuses mainly on the Orkney Islands, where there is a Neolithic landscape rich in sites amazingly preserved by prevalent use of the local stone which appears on the shore ready-split into convenient building slabs.

Evidence from middens shows that the inhabitants kept cattle, sheep and pigs, farmed barley and wheat and gathered shellfish, as well as fishing for species which must be caught from boats using lines.

Finely made and decorated Unstan ware pottery links the inhabitants to chambered cairn tombs nearby and to sites far afield, including Balbrindi and Eilean Domhnuill.

About 6 miles (10 km) from Skara Brae, grooved ware pottery was found at the Standing Stones of Stenness (originally a circle) which lie centrally in a close group of three major monuments.

The widespread connections of these people are shown by offerings imported from Cumbria and Wales and left on the sacred hilltop at Cairnpapple Hill, West Lothian, as early as 3500 BC.