The door-piece in the north wall of the transept (see Fig. 318) is also a prominent feature. It projects about 4 feet 6 inches from the main wall, is carried up two stories, and is roofed in with a sloping stone roof. The lower story contains the doorway (Fig. 319), which is 5 feet 6 inches wide, and has plain jambs. It is set back about 3 feet 6 inches, and the ingoing for about 2 feet is square, and contains two shafts of ordinary size, with a small one between them; then follows a nook containing a shaft, and then the jamb. The shafts have the usual Norman caps and bases. The mouldings of the arch (see enlarged outline in Fig. 319) are peculiar in their profile. They are enriched--the outer one with small medallions, the central one with the billet, and the inner one with rosettes. Above the archway there is an arcade of interlacing round arches, the shafts, which are gone, having Norman caps. The tympanum of the gable is covered with a reticulation of round beads or rolls. [Illustration: FIG. 323.--Kelso Abbey. Upper Stages of Tower.] The tower (see Figs. 315 and 320), of which the south and west sides and a small portion of the north and east sides remain, is 35 feet square over the walls. It is carried up with plain masonry externally, but the interior has immediately over the great arches of the crossing an arcade of round moulded arches, supported on triple shafts similar to those of the choir. Above this arcade is another story containing simple round arched openings, which are lighted on the exterior by circular windows containing quatrefoils. Over this tier is the top story, which contains three pointed and deeply-recessed windows on each side of the tower. Broad flat buttresses are placed at each angle of the tower, similar to those of the main building, and these were, no doubt, originally finished with turrets like those of the transepts. It has already been said that the upper part of the tower is later than the lower part. This is apparent from the pointed windows of the top story, and the quatrefoiled circular windows of the story beneath. The lower story immediately over the great arches is, without doubt, of about the same date as the choir. The approach to the upper floors is now by one staircase in the north-west angle of the transept, but there were, doubtless, other similar staircases in parts of the structure now removed. This staircase gives access to passages which run round the building on every floor (Figs. 321 and 322) between the arcades and the outer walls. In the angles of the tower there are small wheel stairs leading to every floor, and passages running round the tower on every story (Fig. 323.) These arcades and passages have tended to weaken the structure, which it has been found necessary to strengthen with numerous iron tie-rods, iron beams, &c. There was an outer door in the south-west angle of the transept, and another in the north wall of the nave adjoining the crossing.