Dr has guessed, by pacing, the dimensions of the ground plan of the vitrifications on the hill of Dun Mac Sniochain, supposed to have been part of time ruins of Beregonium. Ile acknowledges, that a great part was concealed by being covered with sod, which he had no means of removing; yet he has given a plan of an exten sive and regular set of inclosures. He has not favoured us with the shape of the summit, on which the position of the vilified masses observed elsewhere always depends ; but, from the shading of his plan, we may presume, that the inclosures stand on different elevations, and that those elevations command a view of different portions of coun try. It is stated, that the portion of ground inclosed is in length about 200 yards; whereas on the plan two separate inclosures are marked, one 56 paces long, and the other 37. One side of the latter appears to be prolonged, so as to reach the edge of the hill at both sides. There is a third inclosure, 30 paces long. The want of a vertical section, or a drawing of the hill, prevents us from judging of the extent of Dr M'Culloch's title to set aside the idea of sig nal fires having been the cause of the vitrifications. The facility with which our author makes room for his own opinions, may be seen in the following sentence : " The supporters of this opinion have asserted, that they (the forts) always occupy the highest elevation ; and that many of them are so placed as to be visible from each other. This is not true." The vitrified forts have never been as serted to occupy the highest elevation; and we cannot disco ver where Dr APCulloch could find such an assertion to have been made. We do not remember an instance, in which there is not much higher ground immediately contiguous to the hills on which the vitrifications are found. It has been asserted by others, as well as by ourselves, that they are placed in commanding situations, from which an exten sive view of the sea, or inland districts, can be seen. But this is very different from the highest elevation. That many of them are so placed as to be visible from each other, is known from time testimony of several writers, and is consistent with our own observation.
The rock of which the hill in question is formed is lime stone ; and Dr l\PCulloch very properly infers, that the stone of the hill was rejected, on account of the effects of fire upon it, and that other stones were, therefore, collected in the vicinity. He supposes, that a trap breccia, found in situ about half a mile from the hill, was chiefly made use of, on account of its being fusible. Yet he states, that only the foundation of the wall is cemented together by melted matter. The masses of this rock are said to be rare on the plain ne..r the hill ; but it cannot be inferred from this, that they were not found in sufficient plenty at the time the rampart was constructed. The building of the rampart most probably occasioned the present scar city of stones of this kind on the plain. But this is com paratively unimportant, since we have vestiges, in various places, which demonstrate the great labour which the an cient inhabitants of the country bestowed in collecting stones of particular sizes and shapes to suit their purposes. The vitrification extending, according to Dr M'Culloch, " in no case more than a foot or two from the foundation," does not, in our opinion, exhibit any sign of intention to con struct a vitrified wall ; and the effects of the fire appear ing, in this instance, to diminish upwards, is precisely what we should expect to be the consequence of lighting signal fires against the rampart in the manner we have supposed. The reason why the pudding-stone is the prevailing mate rial, appears in its being more easily broken into pieces of a convenient size than any other stone, and more easily quarried (if quarrying was necessary) than the hard pri mitive rocks.
From what we can collect out of this description, we are inclined to think it possible that a rampart of loose stones has been constructed on the vitrified mass, which is descri bed as the foundation. Should this conjecture prove cor
rect, it will be an additional proof that the fusibility of the materials has not always been made use of for the purpose of cementing them. Indeed Dr M'Culloch comes nearly to the same conclusion, as he has found it necessary to state the following hypothesis, which appears to us a very lame apology for builders neglecting their work ; at all events, Dr AI.Culloch has satisfied us, that the art of building walls, by means of fire, was not, in the presMu case, suffi ciently perfect to raise a structure higher than a foot or two. " The imperfect ustion of the upper parts, may be easily conceived to have arisen from a partial neglect of the fire after the wall had nearly attained its requisite height ; nor is there any reason why it should net have been increased in height, by the addition of cold stone... af ter a firm foundation had been obtained." We do not see Why a foundation of vitrified stones should be firmer than the solid limestone rock, on which they are placed. Dr INIcCulloch observes, that the effects on the stones appear to have been produced by repeated applications of fire; an observation which accords exactly with the supposition of signal fires. \Ve cannot discover, along with our author, -any analogy between the appearances we have been consi dering, and the method employed to bake mud walls in Hindustan. Melting and baking we consider as very different things. In regard to the plan which has been supposed to have been followed in constructing vitrified walls, and which is approved by our author, we have only to observe, that the great heat necessary to fuse the stones, could not possibly be produced between two walls built of sods, or any thing else, which would prevent a proper cur rent of air from passing through the fuel. To us the ana logy to the glazed wall of Gatacre House in Shropshire, appears equally remote.
\Ve hope, by the time we come to the article VITRIFIED Forts, that we shall have it in our power to throw some ad ditional light on this obscure subject. Our remarks in this Article, particularly those on Dr M'Culloch's memoir, spew how difficult it is to arrive at any settled opinion at present; though to us it appears evident that, to whatever use the fusibility of some stones may have been afterwards applied, the lighting of signal fires has caused the vitrifications at least in some instances ; and, if not in all, that it has af forded the hint from which the idea of cementing stones by means of their fusibility has been derived. If it be really the fact, that walls were built in this manner, it is remarkable that no trace is left by which we can determine the method which was followed in their construction. The only data we possess on which our arguments in favour of this mode of building can be founded, are, the presence of great varieties of stones, a few of which are fusible at a high temperature, and of charcoal, which indicates the nature of the combustible materials. It is evident that the hills on which these remains have been discovered have been fortified with more or less care, and to a greater or Iess extent; and the question that remains is simply, What has been the purpose to which the fire, which fused the stones, was applied ?—Was it applied to strengthen the walls by the builders; to destroy them by an enemy ; or, have the vitrifications been the accidental effects of signal fires; or can we trace their origin to all of these ? See Williams's Letters from the Highlands. Archaolo gia, vol. vi. Bee, vol. x. Transactions of the Royal Society Edinburgh, vol. ii. Statistical 4ccount of Scotland, passim. Memoirs of the Wernerian Nat. Hist. Society, vol. i. Trans actions of the Geological Society of London, vol. ii.