The three-arched openings above described are all of about the same dimensions, and as the two eastern ones cannot be called doorways, so neither can the western one be considered as merely the entrance doorway to the church, but would rather appear to be the arched opening from the nave into the tower and chancel. When we consider that this church was once a cathedral, as well as the church of a monastery, and also, perhaps, served the purpose of a parish church, it seems probable that it must have been a larger building than the simple oblong chamber to the east of the tower which now survives. Considerable discussion has taken place with reference to the probable arrangement of the plan. Some have supposed that the church consisted of the simple oblong chamber which still exists, with an eastern apse and western tower; while others maintain that the existing oblong was the choir, that there was a western nave, and that the tower was central. Sir G. Gilbert Scott points out that in the latter case St. Regulus’ would be parallel to Jarrow Church, while in the former case the church may have had a lofty western porch, as had those of Wearmouth and Barton-upon-Humber. Sir Gilbert, however, thinks that the large size of the western arch, and the mark of [Illustration: FIG. 158.--St. Regulus. Belfry Window.] the roof on the tower, suggest a nave.[146] The seals of the church, dated 1204 and 1214, which are preserved at Durham, show a nave and chancel. The chancel is lighted by four windows, two on each side, placed at about 14 feet above the ground. (See Fig. 155.) They are round headed, the circles being cut out of a single stone on the outside, but arched on the inside. The openings are 6 feet 6 inches high and 1 foot 10 inches wide, and have broad splays internally. The building has a cornice at the wall-head, containing a series of simple corbels. A string course runs round the tower below the top story, and above it there is a belfry window on each face, about 3 feet wide by 8 feet 9 inches high. Each window is divided into two openings by a rounded centre shaft (Fig. 158), and there were round nook shafts at each side, but these have now fallen away. There are a few small openings on each face at different stages. The tower is crowned with a cornice, having two rows of simple corbels similar to those of the chancel cornice. On the east side there is an opening into the space which was covered by the chancel roof. The floors of the tower have been of timber, and there is one set-off in the inside of about 6 inches, at a height of about 64 feet. There was no access stair. At the north-west corner of the chancel, and at the wall-head level, there are two caps which have a very distinct appearance of being of first pointed date. NORMAN ARCHITECTURE.