Horned circular cairns occur at three places near Spinningdale. One of them in the wood opposite the small farm of Cnocdubh was excavated some years ago by Mr Curle, who discovered burnt human remains, one or two relics of pottery, and a short tanged flint scraper, now preserved in the National Museum at Edinburgh. The chamber in the cairn at Cnocdubh is built of seven large slabs placed on end. It is floored with flags and has a covering flagstone, over which (before excavation) was piled a cairn of stones 8 feet high. The other horned round cairns near Spinningdale are situated one in Coiloag Wood - near the gamekeeper's cottage - and the other at the west end of Ledmore Wood. There is also a horned round cairn at Aberscross near the Mound station, another on
Lairg Moor, and there are examples in the parishes of Kildonan and Farr. One or two round cairns without horns, but containing burial chambers, are to be found in nearly every parish in the county. These also would appear to belong to the Stone Age, but are probably more recent than the horned cairns and may mark a transition to the Bronze Period.
The cairns testify to the skill as builders of the neolithic people and point to some kind of social organization among them. Near the large cairns there usually occur a number of smaller cairns or mounds - probably the burial places of the members of the tribe. The implements of stone were manufactured with taste as well as skill. Except the cairns and stone implements no other monuments survive of the neolithic men, yet it would seem that this Mediterranean race was far from being extirpated by the successive hordes of invaders who after them possessed the land. They migrated northwards along the east side of the country, and few traces of them survive in the mountainous and western parts of Sutherland. It is remarkable that in the remotest past the inhabitants of the county settled in the districts where to-day population is chiefly to be found. The late Dr Joass, Golspie, collected a considerable number of relics of the Bronze Age (1500 B.C. - 1000 B.C.) in various parts of Sutherland, and these are now preserved in the Dunrobin Museum and in the National Museum at Edinburgh. In the Bronze Period a race of people from central Europe spread over the British Isles introducing a more advanced civilization than that of the neolithic people. Their burial customs were simpler. The remains of their dead are found in stone cists, sometimes in small cairns, but frequently in the earth a few feet below the surface. Some years ago on the farm of Little Creich the covering slab of a stone cist was turned up by the plough. One or two cairns of the Bronze Period, with cists, occur in nearly every parish on the east side of the county. One cairn has been excavated and the cist exposed at Tulloch near Bonar bridge. A large cairn was opened at Maikel, near Bonar bridge, in 1853. In it there was a cist containing an urn with burnt human remains and a bronze blade. There are many hut circles and small mounds in various parts of the county, which may mark the site of dwellings and burial places:
At the west end of Loch Migdale there is an artificial island, on which, as late as the seventeenth century, stood a dwelling, referred to by Sir Robert Gordon, who also states that a hunting seat belonging to the Earl of Sutherland was built upon an island at the south end of Loch Brora. These artificial islands may date from the Bronze Age. There is a similar artificial island in Loch Doulay. In the neighbourhood of these islands fine examples of stone implements and other relics have been found. Near Tulloch, for example, there was dug up a stone cup, having handles like the wooden quaich of a later time. Some years ago a hoard of ornaments of the Bronze Period was discovered at Badbeith on the north side of Loch Migdale. A cist in a small circular cairn on Embo links was excavated by Dr Joass in 1872. The covering slab of this cist has a cup mark which antiquarians connect with sun-worship. To the south-west of Loch-An-Trill, near Dornoch, is a cairn which appears to have contained a cist. Burial cairns of the Bronze Age occur at Aberscross, where there are other remains of this period, notably a stone circle close to the roadside, about half a mile from the Mound station.
The brochs form the chief monuments of the Iron Age, which succeeded the Bronze Period. There are one or two fairly well-preserved brochs in the county, such as Dun Dornadilla in Strathmore and Castle Cole in Strathbrora. The latter is the smallest but most strongly situated of all the Sutherland brochs. Carn Liath, a mile to the east of Dunrobin Castle, and close to the railway, was excavated and carefully examined by Dr Joass, who found in it shale rings, two steatite cups and two plates of brass (all now preserved in Dunrobin Museum). Brochs have been excavated at Carrol on the west side of Loch Brora, at Kintradwell in the parish of Loth (where upwards of fifty quern stones and many spindle whorls were found), at Backies near Golspie and at Sallachaidh near Loch Shin. The official report upon the historical monuments of Sutherland contains a list of sixty-seven brochs. The people of the Iron Age have left few traces in the west of Sutherland, yet the broch at Clachtoll near Stoer is one of the finest in the county. Brochs are most numerous in the parishes of Kildonan and Farr.
Hut circles, which form an important class of ancient relics in the county, are to be found all over the eastern parishes. These ancient monuments are referable to different periods, from early prehistoric times down to the comparatively recent date when the erection of rectangular buildings became common. Striking examples of these remains or circular structures occur at Swordale in Creich, Cambusmore Hill in the parish of Dornoch, Abercross in Golspie, Achnagarron in Rogart, and Ascaig in Kildonan. An elaborate hut circle in Rogart may be said to represent a homestead of the prehistoric period.
Early Christian monuments are represented by stones carved with crosses, Christian symbols and late Celtic ornamentation. Several examples of these excised stones were found in the parishes of Golspie and Clyne when the Sutherland railway was under construction, and they are now preserved in the Dunrobin Museum. The finest example in the county of early Christian stone carving is a Celtic cross slab in the churchyard of Farr. It is 7 1/2 feet in height, with ornamental spirals and characteristic interlaced work, the ornamentation including a figure of two birds with their necks intertwined.
The Farr cross is one of the finest examples of Celtic art that has come down from the early Christian period.