and, if so, where placed and how hung? It is known that in many cottages in old times the door was an animal’s hide hung across the opening, and probably this may have been the case in these unrebated church entrances. Possibly this plain jamb may be an evidence of antiquity; though Egilsey and Kirk of the Ness in Yell have the usual form of jamb. Probably this doorway was surmounted by a semicircular arch, though many of the ruder chapels had square-headed doorways with a large stone lintel, as at Lybster, Caithness. There are very few instances of the passage between a nave and chancel being square-headed. Where there is a semicircular arch on plain jambs, as in the doorways beforementioned, and in some chancel arches, as at Linton, Shapinsay; Kirk of the Ness, Yell; Wyre, &c., there is generally a peculiarity which may be mentioned here--the feet of the arch are set back on the jambs at the imposts two or three inches on each side. This was probably to support the centre on which the arch was built, instead of supporting it by props from the floor. [Illustration: FIG. 108.--Church on Brough of Birsay. North Side Elevation.] In the north-east and south-east corners are two circular spaces 5 feet 6 inches in diameter (see Fig. 108), the south one of which contains a freestone stair step, and the north one some broken stone. Probably both were staircases; but how high they reached, to what they led, and what was the superstructure we can only conjecture. One or both may have led to turrets, or to priests’ rooms over the chancel arch, or chancel or nave. We cannot suppose a rood-loft to have existed here. The support of the west side of the stairs is now gone, but we must suppose that a block of masonry existed which included the circle of the staircase. Against this, the _seat_ on the south apparently runs past the spot at which it should have stood, and there are no decisive traces of a junction in the north and south walls. There is no other solution of the difficulty. This very massive separation between nave and chancel is probably unique. M‘Cormac’s chapel at Cashel has a turret and a chamber in nearly the same positions as these staircases; but the construction in that case is clear.[132] A stone seat, 1 foot 2 inches high and 1 foot 2 inches wide, ran all round the nave--at least, it was traced at west doorway and at the east end of the south wall of the nave. The roof was probably of tie beam construction, and covered with stone slabs.