was to consolidate a wall which was composed of small stones such as could be gathered around the site. At the vitrified fort of Carradale, in Cantyre, may be seen an uninterrupted portion of wall, upwards of 100 feet in length, which is absolutely consolidated for three, four and five feet from the top. In one or two places, where previous visitors had picked a hole right through the wall, it was clearly seen that the vitrifaction was less in the lower and central parts and disappeared altogether at the base, which consisted mostly of water-worn stones.
Outside the Scottish area the distribution of vitrified forts is somewhat remarkable. Four are stated, on the authority of Dr. Petrie, to be in Co. Londonderry and one in Co. Cavan, Ireland. They are, however, to be found in Brittany and Normandy, Saxony, Bohemia, Silesia, Thuringian Forest and the Rhine district.
Lake Dwellings.—The security afforded by natural islands probably first suggested the idea of constructing artificial abodes in lakes and marshes. But whatever were the precise circumstances of their origin, it is certain that lacustrine dwellings continued for many centuries to be the favourite system of protection adopted by the early races of Europe, wherever the requisite hydrographical conditions were to be found. The plan of construction was to plant a series of upright piles in a selected portion of the shallow
