It must also be noticed that few, if any, of them can be classified as exclusively belonging to the earlier ages, like those so numerously recorded in Central Europe. Indeed, there are only two or three which have any claim to such delimitation, viz. those in Coal-bog (Kilnamaddo), in Drumkelin bog, county Donegal, and in Holderness. On the two former sites were found the most perfect examples of log-huts that have yet come to light, and as they were both deeply buried in peat, 17 and 25 feet respectively, they undoubtedly point to some antiquity. But the relics, which include a stone axe and some flint objects, are too few to justify such a sweeping conclusion as that these dwellings were constructed at a period when metal implements were unknown in the country. At any rate, there can be no reasonable doubt that the period of greatest development of the Scottish and Irish lake-dwellings was during the Iron Age, and, at least, as far posterior to Roman civilisation as that of the Swiss Pfahlbauten was anterior to it.
In instituting an inquiry as to how far the geographical distribution of crannogs coincides with that of the various nationalities of the period, we arrive at some striking results. Thus adopting Skene's division of the four kingdoms into which Scotland was ultimately divided by the contending nationalities of Picts, Scots, Angles, and Strathclyde Britons, after the final withdrawal of the Romans, I find that of the fifty or sixty crannogs proper none are located within the territories of the Angles; ten and seven are respectively within the confines of the Picts and Scots; while all the rest are situated in the Scottish portion of the ancient kingdom of Strathclyde. That they have not been found in the south-eastern provinces of Scotland may be due to the rarity of suitable lakes, or the want of proper research on the part of antiquaries; but, as the matter actually stands, their absence suggests the theory that these districts had been occupied by a foreign element before Celtic civilisation gave such a prominence to the lake-dwellings. It will be thus seen that in the early centuries of the Christian era the distribution of crannogs in Scotland and Ireland closely coincides with a well-defined area in which the Celtic language was spoken. For proof that in those days this was the language of the south-west of Scotland, I need only point to the recent work of Sir Herbert Maxwell on the topography of Galloway.
But from an etymological analysis of the earliest topographical nomenclature of Britain, it is inferred that, during still earlier times, a much larger portion of Britain, if not the whole of it, was under the sway of the Celts. Hence it becomes interesting to inquire if, in these localities, from which Celtic influence was expelled, there exist traces of lake-dwellings. In localities where the Celtic races were never supplanted by foreigners, it would be strange indeed, and altogether at variance with archæological experience, if the habit of resorting to isolated and inaccessible islands for safety would be all at once abandoned, whenever the greater security afforded by stone buildings became known. Hence the persistence with which the island forts continued in these Celtic regions. But in this wider Celtic area, on the supposition that the Celts were the introducers or founders of the system, we ought to find some vestiges of these dwellings along the regions traversed by them before they became isolated from their Continental brethren, and cooped up in the western districts of Britain. This is precisely what the general researches into British lake-dwellings have shown in the stray remnants of them that have been found in Llangorse, Holderness, the meres of Norfolk and Suffolk, Cold Ash Common, etc. All these, with perhaps the exception of the pile-structures at London Wall, appear to be older than the majority of the crannogs of Scotland and Ireland.
Taking all these facts into account, together with the distinct statement made by Cæsar that the Britons were in the habit of making use of wooden piles and marshes in their mode of entrenchments, I am inclined to believe that we have here evidence of a widely distributed custom which underlies the subsequent great development which the lake-dwellings assumed in Scotland and Ireland. Moreover, I believe it probable that the early Celts had got this knowledge from contact with the inhabitants of the pile-villages in Central Europe. On this hypothesis it would follow that the Celts had migrated into Britain when these lacustrine abodes were in full vogue in Switzerland, and that they retained their knowledge of the art long after it had fallen into desuetude in Europe. Subsequent immigrants into Britain, such as the Belgæ, Angles, etc., would cultivate new and improved methods of defensive warfare; whilst the first Celtic invaders, still retaining their primary ideas of civilisation, when harassed by enemies and obliged to act on the defensive would have recourse to their inherited system of protection, with such variations and improvements as better implements and the topographical requirements of the country suggested to them. It is as defenders, not as conquerors, that the Celts constructed their lake-dwellings.
This hypothesis, which was first enunciated in my work on "Ancient Scottish Lake-dwellings" as a mere conjecture, has elicited a considerable diversity of opinion on the part of critics. In the Times of October 4th, 1882, it is thus referred to:—"This is pure theory, and is quite unnecessary to account for the facts: as well might one argue a connection between the pile-dwellers of New Guinea and Central Africa and those of the Swiss lakes." Sir John Lubbock (Nature, December 24th, 1882) confesses that he is disposed to doubt that there is any connection between the geographical distribution of the Scottish lake-dwellings at present known and that of the ancient Celts. On the other hand, another reviewer attempts to defend it on the ground that "in the Swiss lake-dwellings of the Iron Age there are indications, especially in the ornamentation of the sword-sheaths and other articles, of a style of art which closely corresponds to the style of decoration prevalent in the crannogs of Scotland and Ireland (Scotsman, November 22nd, 1882).
The indications above alluded to in support of this hypothesis as based on a comparison of the relics, will be more appropriately discussed in my next lecture, when I come to review the lake-dwellings of the Iron Age in Central Europe. There are, however, one or two objections urged on the other side—as, for example, the difference of structure and late occupancy of the crannogs, as compared with the Swiss lake-dwellings—that require now to be shortly considered.
As to the supposed difference in structure, I need only refer to the structural details of various fascine-dwellings, as in the lakes of Fuschl, Schussenried, Niederwyl, Inkwyl, Wauwyl, etc., as a sufficient proof of the resemblance between them and the Scottish and Irish crannogs. It is true that the pile-dwellings were more numerous on the Continent than the fascine structures, while the reverse is the case in Scotland and Ireland—if indeed the former can be said to have existed at all in these countries. That the pile system was, however, known to the crannog-builders, and occasionally acted upon, we are not devoid of some positive evidence. Mr. G. H. Kinahan says that a few of the Irish crannogs were built on piles (B. 119, 2nd ed. p. 654), and instances an example in Loch Cimbe (now Loch Hackett), county Galway, which was so frequently blown down that the occupiers were obliged to convert it into an island, which they did by adding boat-loads of stones to its site. One of the lake-dwellings in Lough Mourne I concluded to have been a pile-dwelling ([see page 386]), and it was connected to the shore by a wooden gangway. Mr. Burns Begg describes remains of a pile-dwelling in Loch Leven as an "oblong wooden platform, raised above the water on piles, twelve feet or upwards in height." (B. 460.)
Subsequently I had an opportunity of visiting the locality, along with Mr. Burns Begg, and I am convinced these remains could not have been an ordinary submerged crannog or artificial island. The lake bottom is not soft and compressible, but, on the contrary, very compact and quite incapable of yielding to any great extent. The structures, even in the present reduced level of the loch, are never less than 1 or 2 feet below the surface; but as formerly there would have been 9 feet more of water over them it is quite improbable that this amount of submergence could be accounted for by the usual subsidence or compression of the submerged materials.
Some of the examples of lake-dwellings recorded in England, such as those described by Sir Charles Bunbury and Dr. Palmer, would appear also to have been pile-structures.
If, therefore, both principles were known among the crannog-builders of the British Isles, why, it may be asked, did they give a preference to the fascine structures? I have already remarked that these structures on the Continent were confined to small mossy lakes, which, owing to the yielding nature of their sediments and peaty deposits, were unsuitable for pile-dwellings. In such conditions, which are generally prevalent in Scotland and Ireland, the wooden island supplied more readily, and perhaps with less labour, the requisite stability for platforms in boggy lakes and marshes intended for huts and other superstructures, especially when these platforms were small and the islands sparsely placed.