The ancient ironworks of Gairloch were probably not more numerous than those of some other parts of the Highlands and Islands. There is little doubt but that many of the remains, both in Gairloch and elsewhere, have been obliterated by the husbandman, or concealed by overgrowth of heather and other plants. In many places throughout Sutherlandshire, Ross-shire, and Inverness-shire, as well as in other Scottish counties, there are large quantities of iron slag. The Inverness Scientific Society have examined remains of ancient iron-smelting near Alness in Easter Ross. The Rev. Dr Joass, of Golspie, and Mr D. William Kemp, of Trinity, have to a certain extent investigated some Sutherlandshire remains. There are also quantities of slag on the Braemore estate, on the shores of Loch Rosque between Achnasheen and the eastern boundary of Gairloch parish (Part IV., chap, iii.), and in many other parts of Wester Ross, as well as in the island of Soa off the west coast of Skye, and many other places. At the iron-smelting works near Alness a native hematite iron ore was used, as well as what is termed bog iron. Bog iron is also believed to have been used at a bloomery near Golspie, Sutherlandshire. This bog iron appears to have been commonly employed by the ancient ironworkers; it was extracted by the action of water from ferruginous rocks and strata, and was accumulated at the bases of peat bogs. In process of time granular masses of oxides of iron were thus formed, sometimes covering a considerable area. Within the parish of Gairloch there are still quantities of bog iron to be seen, apparently formed exactly in the manner described. The localities will be stated in Part I., chap. xix. No bog iron has been found in proximity to any of the remains of ironworks; probably the iron-smelters consumed all that was conveniently near the scenes of their operations. In the neighbourhood of all the remains of ironworks in Gairloch are found ferruginous rocks and shales, or rust-coloured earths. The best samples of these rocks have on analysis yielded but eight per cent. of metallic iron, and the rust-coloured earths are by no means rich in the metal. But there can be no doubt that bog iron was formerly present in the vicinity of these rocks, shales, and earths; and the analyses of the ancient iron slags prove to demonstration that such bog iron was the ore used at the ancient bloomeries.