Three feet from the ground there is interiorly, in the south wall, a small four-sided recess,[48] 1 foot in breadth, and 15 inches in height and depth. (See C in ground plan, Fig. 4; and also Fig. 8.) In the same south-side wall, near the western gable, is an opening extending from the floor to the spring of the roof. It has apparently been the original door of the building; but as it is now built up by a layer of thin stone externally, and the soil of the garden has been heaped up against it and the whole south wall to the depth of several feet, it is difficult to make out its full relations and character. There is a peculiarity, however, about the head of this entrance which deserves special notice. The top of the doorway, as seen both from within and from without the building, is arched, but in two very different ways. When examined from within, the head of the doorway is found to be composed of stones laid in the form of a horizontal arch, the superincumbent stones on each side projecting more and more over each other to constitute its sides, and then a large, flat, horizontal stone closing the apex. (See woodcut, Fig. 5.) On the contrary, when examined from without, the top of the doorway is formed by stones laid in the usual form of the radiating arch, and roughly broken off, as if that arch at a former period had extended beyond the line of the wall. (See woodcut, Fig. 6.) This doorway, let me add, is 5 feet high, and on an average about 4 feet wide,[49] but it is 2 or 3 inches narrower at the top, or at the spring of the arch, than it is at the bottom.[50] The north side wall of the building is less perfect; as, in modern times, a large rude opening has been broken through as an entrance or door (see woodcut, Fig. 7, and ground-plan, Fig. 4), after the original door on the other side had become blocked up.
Fig. 5. Horizontal arch of the door, as seen from within the cell.
Fig. 6. Semi-circular arch of the door as seen from without, the garden earth filling the doorway.
The eastern gable is still very entire, and contains a small window,[51] which, as measured outside, is 1 foot 11 inches in height, and 10 inches in breadth. But the jambs of this window incline or splay internally, so as to form on the internal plane of the gable an opening 2 feet 3 inches in breadth.
Fig. 7. Eastern gable and north side of the building.
The squared sill stone of the window is one of the largest in the eastern gable. Its flat lintel stone projects externally in an angled or sharpened form beyond the plane of the gable, like a rude attempt at a moulding or architrave, but probably with the more utilitarian object of preventing entrance of the common eastern showers into the interior of the cell. The thin single flat sandstones composing the jambs are each large enough to extend backwards the whole length of the interior splay of the window, and, from the marks upon them, have evidently been hammer-dressed.[53] Internally, in this eastern gable, there is placed below the window, and in continuation of its interior splay, a recess about 18 inches in depth, and of nearly the same breadth as the divergence of the jambs of the window. The broken base or floor of this recess is in the position of the altar-stone in some small early Irish chapels.
The accompanying sketch (see woodcut, Fig. 7) of the exterior of the eastern gable shows that the stones of which it is built have been prepared and dressed with sufficient care—especially those forming the angles—to entitle us to speak of it as presenting the type of rude ashlar-work. The stones composing it, particularly above the line of the window, are laid in pretty regular horizontal courses; lower down they are not by any means so equable in size. The masonry of the side walls is much less regular, and more of a ruble character. The walls are on an average about 3 feet in thickness.[54] The stones of which the building is composed are, with a few exceptions, almost all squared sandstone. The exceptions consist of some larger stones of trap or basalt, placed principally along the base of the walls. Both secondary trap and sandstone are found in situ among the rocks of the island. A roundish basalt stone, 2 feet long, forms a portion of the floor of the building at its southern corner. At other points there is evidence of a well-laid earth floor. The whole interior of the building has been carefully plastered at one time. The surface of this plaster-covering of the walls, wherever it is left, is so dense and hard as to be scratched with difficulty. The lime used for building and cementing the walls, as shown in a part at the west end which has been lately exposed, contains oyster and other smaller sea-shells, and is as firm and hard as some forms of concrete.