Evident traces of a kitchen midden were discovered in the bog close to the hut, but at a level slightly above it. The height of the interior of the most perfect of the huts, without making any allowance for a sloping roof, being only four feet, they would thus correspond to the souterrains of a rath. It has been suggested that they were used by the crannog occupants only for the preservation of perishable commodities; and in seeming corroboration of this theory, large lumps of the substance called “bog-butter” were discovered in them carefully rolled up in cowhide. It is difficult to arrive at even an approximate estimate of the age of these curious structures: the mortise-holes, pierced clean through timbers more than seven feet in circumference, could hardly have been formed by the aid of stone hatchets or chisels: several of the piles and other portions of the work show traces of long, clean cuts, such as are given by sharp metallic tools; yet the only implements found here were of stone, and by the aid of such it is possible that some of the timbers were more or less worked. The roots and part of the trunk of a yew were found _in situ_ in the bog, on a higher level than the roof of the more perfect hut. It has been computed, from the girth of this yew, that it would take at least one thousand years to attain the bulk it showed when first laid bare, and the eleven feet of bog by which it was covered would take at least another thousand years to grow.[53] [Illustration: Plate I. Crannog Hut, Kilnamaddo. Restored from existing Remains.] Plate I., fig. 4, represents the most perfect of the Kilnamaddo huts restored. When the drawing was taken, all the timbers in the illustration were on the spot, and some of these retained their original position. Fig. 3 is a slab of oak measuring six feet by two feet nine; it is not so thick as fig. 2, which represents a slab of oak five feet ten inches in length by one foot six inches in breadth, the depressions at its broader end being five inches by six, and it is one foot two inches in thickness; this and fig. 3 were found lying by the side of the hut, and it is conjectured that they formed a portion of the roof. Fig. 1 represents an angle-post five feet six inches in length, and four feet ten inches in circumference. This style of construction appears, as far as is yet known, to have been confined to the north-west portion of Ireland, the two somewhat similar huts being those discovered by Captain Mudge in Donegal, and by Mr. Morant in Monaghan.