A large accumulation of wood or peat-ashes shewed that it must have been occupied for a lengthened period; and this was further proved by the great quantity of the bones of domestic animals scattered about the place. Those of sheep, apparently of the small northern breed still found in Orkney, were the most numerous; but besides these, there were skulls and bones of horses and oxen, the skull and portions of the horns of a deer, and a large bone of a whale. A thick layer of the shells of the periwinkle, _L. Littoralis_, covered the building and the adjacent ground, mixed sparingly with the oyster, the escallop, the common whelk, and other edible mollusca, which had evidently been consumed in great quantities on the spot. Along with these were also found a few extremely rude implements, the relics of the primitive arts of the builders, besides an antler of a deer artificially severed from the complete tyne. These objects were roughly fashioned from the thigh-bone of an ox, and designed apparently as handles for some weapon or cutting implement, most probably of shell or flint. Other Orkney relics of the same interesting class, but exhibiting more completeness of design, and accompanied with attempts at ornament, are described and figured in a subsequent chapter. This large, though very imperfect example of the dwellings of primitive communities of the ancient population of the Orkneys, may be properly classed with the weems of the Scottish mainland, though it is not entirely subterranean. The floor is nine feet below the natural surface of the ground; and from the mode by which the whole appears to have been in-roofed with immense overlapping stones, it must have projected somewhat above the surface, and was probably covered over with a raised mound of earth. In this respect it approaches, in some degree, to another class of buildings, which appear to be peculiar to Orkney and the neighbouring districts of Caithness and Sutherland, though it is possible enough that they may have been at one time no less common on the whole Scottish mainland. These structures, for which it may be convenient to retain the popular name of _Picts' houses_, are not strictly speaking, subterranean, but erected generally on the level ground, or, at furthest, excavated in part out of the side of a hill, so as to admit of a level entrance. Externally they are scarcely distinguishable from the larger tumuli, but on digging into the green mound it is found to cover a series of large chambers, built generally with stones of considerable size, and converging towards the centre, where an opening appears to have been left for light and ventilation. These differ very little from many of the subterranean weems, excepting that they are erected on the natural surface of the soil, and have been buried by means of an artificial mound heaped over them. Barry has minutely described one, which he calls an "ancient Pick house," opened