About ·90 metre above the arch of the door stands a very shallow calotte covering the niche. The face of the calotte is recessed, which enhances its decorative value by giving it a double outline. As Dr. Reuther has observed,[18] the calotte is not ‘the segment of a pointed dome, but its curve in horizontal section springs sharply back from the face of the archivolt and flattens rapidly behind. Thereby the effect of the shadow is strongly felt at the edge, and the calotte seems to be deeper and more markedly vaulted than it is in reality’. At the base of the calotte there is a small niche which has been broken through owing to the partial ruin of the dome behind it.[19] In the wall on either side of the calotte there is a shallow arched niche. The arch is carried on pairs of engaged columns and is enclosed in a rectangular label. Above the calotte are the three windows of the first floor room, 88, covered by segmental arches. The windows are framed by engaged columns which carry stilted round-arched calottes. The south wall of the great hall is partly ruined. The doorway seems to have been of the same proportions as the door in the north wall, but it was not set back within a niche. The small decorative niches reappear on either side, and there were probably three windows opening into room 101 in the upper story, indeed on the west side the window jamb can still be seen. Even with these windows the great hall must have been most insufficiently lighted, since neither its doors nor its windows open directly on to the exterior of the building. To the south lay the small rectangular chamber, No. 27, which was probably, as Dr. Reuther suggests, covered by a dome similar to the dome of No. 4. It opens to east and west into the vaulted corridor 28, and on the south into the central court. Holes for wooden beams can be seen on the north wall of the great hall, two on either side of the portal niche, one on either side of the shallow decorative niches, and one on either side of the group of windows. On the south wall they have been somewhat differently disposed, one on either side of the door at the level of the arch, one almost immediately above, higher than the top of the arch, and three higher up still, following the curve of the vault (Plate 14, Fig. 2).