picture of highly mobile people, often using sites seasonally and having boats for fishing and for transporting stone tools from sites where suitable materials were found. 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. At a rock shelter and shell midden at Sand, Applecross in Wester Ross facing Skye, excavations have shown that around 7500 BC people had tools of bone, stone and antlers, were living off shellfish, fish, and deer using "pot boiler" stones as a cooking method, were making beads from seashells, and had ochre pigment and used shellfish which can produce purple dye. Farmers and monument builders Neolithic farming brought permanent settlements. At Balbridie in Aberdeenshire crop markings were investigated, and ditches and post holes found, revealing a massive timber-framed building dating to about 3600 BC. An almost identical building, with evidence of pottery, was excavated at Claish near Stirling. On the islet of Eilean Domhnuill, in Loch Olabhat on North Uist, Unstan ware pottery suggests a date of 3200–2800 BC for what may be the earliest crannog. 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. There are many other examples across the country, many under the care of Historic Scotland. At the wonderfully well preserved stone house at Knap of Howar on the Orkney island of Papa Westray (occupied from 3500 BC to 3100 BC) the walls stand to a low eaves height, and the stone furniture is intact. 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. The houses at Skara Brae on the Mainland of the Orkney Islands are very similar, but are grouped into a village linked by low passageways. This settlement was occupied from about 3000 BC to 2500 BC. Pottery found here is of the grooved ware style which is found across Britain as far away as Wessex. About