2. Historical and traditional phenomena associated with their area of distribution. 3. Mechanical skill displayed in the structure of the wooden islands. 4. Topographical changes in the lake-dwelling area during or subsequent to the period of their development. 5. Chronological, social, and other indications derived from the relics. SECTION I. _Classification and Geographical Distribution of Ancient Scottish Lake-Dwellings._ The notices of artificial islands in Chapter II. are confined to such as were found to be constructed on timber or surrounded by stockades. There are, however, many others still extant in several of our Scottish lakes, which appear to be entirely composed of stones and earth irregularly heaped together. In the absence of any historical knowledge as to their age there is no _prima facie_ reason why some at least should not be contemporary with the former, as it cannot be assumed that the crannog-builders made wood a _sine qua non_ in the structure of islands. There were, no doubt, certain stagnant marshes and small lochs in which a wooden foundation was essential for the formation of an island, owing to the softness and yielding nature of the mud; but, on the other hand, there were others with compact, rocky, or gravelly beds, in which any solid materials, as stones, earth, turf, etc., would be equally suitable. The outlets of the larger lakes, more especially of such as were formed in glacial and rock-cut basins, were more adapted for the latter, and as far as my observations have enabled me to form an opinion, these are the very situations in which the stone islands are now found to prevail. Some of them are mere shapeless cairns, without any indications of having been formerly inhabited, while on others are to be found some remains of stone buildings. As to wooden huts or houses, had such structures been erected over them, it is not likely that they could, for any length of time, have resisted the decaying tendencies of a Scottish climate, so that all traces of them would have disappeared long ago.