Page:Transactions of the Geological Society, 1st series, vol. 2.djvu/270

260 which were used for signals. The supporters of this opinion have asserted that they 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 fort at Amworth is not on the highest ground it might have occupied, nor is the fort of Dun Mac Sniochain so situated: but they are both on the strongest ground. Where the strongest and highest ground coincide, a case very common in hilly countries, (I speak of military strength of ground as connected with ancient modes of warfare) there, as at Craig Phadric, they naturally occupy the summit. I may add, that no fort has hitherto been discovered between this and Craig Phadric, except that at Dun Dheairduihl, nor have any been observed in its neighbourhood in other directions. I might strengthen this argument by referring to the descriptions of other similar works, but I prefer arguing from those which I have seen.

It now remains to enquire, if by any examination of the walls of Dun Mac Sniochain, light can be thrown on the causes of its vitrified appearance, and whether it was the result of design or of accident.

The remains of walls in the other vitrified forts, noticed by different observers, have been so well described, as far as relates to their general appearance, that little can be added on this head. It may be sufficient to say, that they appear in the present work to be about twelve feet in thickness, and are now nearly buried under the soil.

One circumstance however requires attention, as some false speculations have been founded on it. Both the outside and inside of the walls near the ground are rendered much thicker than their true measurement shows, by a heap of loose stones accumulated against them, and this renders it difficult in the present state of things to ascertain their real dimensions. It has been supposed that this