Indeed, some of the remains in Ireland can only be compared to the pyramids of Egypt, so massive are the blocks of stone used in their construction.  As this stone is frequently of a kind not to be found in the immediate neighbourhood, the means used for their transportation are as much a matter of surprise and conjecture, as those by which they were placed in the position in which they are found.  The most remarkable of these forts may still be seen in the Isles of Arran, on the west coast of Galway; there are others in Donegal, Mayo, and in Kerry.  Some of these erections have chambers in their massive walls, and in others stairs are found round the interior of the wall; these lead to narrow platforms, varying from eight to forty-three feet in length, on which the warriors or defenders stood.  The fort of Dunmohr, in the middle island of Arran, is supposed to be at least 2,000 years old.  Besides these forts, there was the private house, a stone habitation, called a clochann, in which an individual or family resided; the large circular dome-roofed buildings, in which probably a community lived; and the rath, intrenched and stockaded.

But stone was not the only material used for places of defence or domestic dwellings; the most curious and interesting of ancient Irish habitations is the crannoge, a name whose precise etymology is uncertain, though there is little doubt that it refers in some way to the peculiar nature of the structure.

The crannoges were formed on small islets or shallows of clay or marl in the centre of a lake, which were probably dry in summer, but submerged in winter.  These little islands, or mounds, were used as a foundation for this singular habitation.  Piles of wood, or heaps of stone and bones driven into or heaped on the soil, formed the support of the crannoge.  They were used as places of retreat or concealment, and are usually found near the ruins of such old forts or castles as are in the vicinity of lakes or marshes.  Sometimes they are connected with the mainland by a causeway, but usually there is no appearance of any; and a small canoe has been, with but very few exceptions, discovered in or near each crannoge.

Since the investigation of these erections in Ireland, others have been discovered in the Swiss lakes of a similar kind, and containing, or rather formed on, the same extraordinary amount of bones heaped up between the wooden piles.

The peculiar objects called celts, and the weapons and domestic utensils of this or an earlier period, are a subject of scarcely less interest.  The use of the celt has fairly perplexed all antiquarian research.  Its name is derived not, as might be supposed, from the nation to whom this distinctive appellation was given, but from the Latin word celtis, a chisel.  It is not known whether these celts, or the round, flat, sharp-edged chisels, were called Lia Miledh, “warriors’ stones.”  In the record of the battle of the Ford of Comar, Westmeath, the use of this instrument is thus described:—­