Mr. Mulvany, Commissioner of Public Works, makes the following remarks on the general features of construction of the crannogs encountered by them during these drainage operations prior to the year 1852:—
Fig. 114.—Section of Ardakillen Crannog, near Strokestown.
Fig. 115.—Plan of Crannog in Drumaleague Lough. Outer circle 60 feet in diameter.
"1. They are surrounded by stakes, driven generally in a circle from 60 to 80 feet in diameter; but in some cases the inclosure is larger, and of an oval shape, as, for instance, that in Loughtown Lake, which is 120 feet from east to west and 100 feet from north to south; and one of those in Lough Mac Hugh, which measures 118 feet in one direction and 74 feet in another.
"2. These outside stakes are generally of oak from 4 to 9 inches in diameter; sometimes driven in a single row, sometimes double, and in some cases, as that of island No. 1 in Drumaleague Lake, the stakes are found in a single row in parts of the island, and in double or treble rows, or clusters, in other parts. The island in Loughtown Lake differs from the others in being surrounded by a mass of stakes upwards of 15 feet wide, and rather inclined towards the centre of the island.
"3. The portions of the stakes remaining in the ground are evidently the lower ends of young trees, or of branches of large trees, which were stuck down just as they grew in the wood; the thicker end downwards, and bearing the marks of the hatchet by which they were felled. A considerable length of these stakes must, therefore, have projected over the ground; and they may probably have been joined together by horizontal branches, interlaced so as to form a screen, well calculated to serve for shelter or defence. All the portions of the stakes which were above ground have been destroyed by time; but the portions remaining below ground, particularly where the stratum is pure peat, are generally very sound at heart, and have become as black as the oak usually found in bogs.