That some of them are comparatively of recent erection is evident from the fact that at Roscrea in Tipperary, the tower has a pointed or Gothic arch, 38 feet from the ground. Now the 12th century is generally allowed to be the era of the introduction of the Gothic architecture into this country; and from this a curious question arises. It is moreover a curious fact, not hitherto noticed by any writer upon this subject, that the isolated tower, probably of Moorish origin, which stands on the neutral ground at Gibraltar, bears a very striking resemblance, in all points, to the Irish round towers in general. This tower has been seen and examined by the editor, who was much struck by the similarity at the time, and has since endeavoured to procure all possible information upon the subject. It is well known that Gibraltar was not inhabited by the Phœnicians, Carthaginians, nor Romans, nor even by the Visigoths, but was first taken possession of by the Saracens in 711; fourteen years after which the Moorish castle was built, followed by other edifices, with the pointed Saracenic arch, until the rock returned to the dominion of Spain in 1462. It may be added here, that the Irish towers have a strong resemblance to the Oriental minarets, especially in their supposed use as places for calling the people to worship. Where there are so many and so discordant opinions it is difficult to decide; but the tourist may avail himself of these hints in his further researches. Of the precise antiquity of the RATHS, or Danish Mounts, few doubts exist. These are circular mounts of earth, from 40 to 150 feet in diameter at the base, and conically diminishing towards the top. Common tradition gives them to the DANES; and no doubt a great proportion of them are not older than the occupation of the northern and eastern coasts by the Ostmen. But some must be of the earliest Scandinavian date; particularly the _Giant's Ring_ near Belfast, and the _Rough Fort_ near Templepatrick, which have Druidical remains incorporated with them, and in their very centre. Besides, though the term _Danish_ is universally applied to these works, yet some of them are also undoubtedly _Norwegian_, particularly one near Fore in Westmeath, called the "Fort of Turgesius," positively described by _Giraldus_ as the work of a Norwegian chieftain, and raised for a castle, using the word "Castella," and not _Castrum_.