A very beautiful arcade runs completely round the walls. It is of trefoil arches, deeply and richly moulded, supported on marble columns carved with foliage. Over the arches is a hood mould terminating with heads. In the spandrels are a series of deeply-sunk and moulded quatrefoils, two of which contain sculpture. The bases of the columns rest on a plinth. Surmounting this arcade is a moulded string, from the level of which rise the windows, and above the windows another string course and a second range of windows. In the centre bay, however, is the large rose window, which is over thirty feet in diameter.
The division of the chapel into three bays is effected by two main vaulting arches, which spring on the western side from the piers of the east end of the choir, and on the eastern side from responds of clustered shafts alternately of marble and stone, banded at intervals and having richly carved capitals. The arches themselves are deeply moulded and ornamented with dog-tooth ornament and foliage. The vault of the central bay has eight ribs—two springing from each of the clusters just described, and two from each of the choir piers. The vaulting of the remaining bays is quadripartite, but has peculiarities which are worthy of notice, arising from inequality of width. We must not omit to call attention to the exquisite sculpture of the vaulting. The centre has figures of the Four Evangelists, while in the north is a beautifully executed carving of vine and grapes, and in the south, figure subjects. Among the sculptured heads on the wall arcade at the south end, at the western side of the two bays into which the south wall is divided, are two which are portraits of the men to whom we owe the design and execution of the beautiful sculpture of this chapel. One is an elderly man, the other much younger, and both wear linen dust-caps over their heads.
The nine lancet windows were originally filled with ancient stained glass, which, as the reader will remember, was removed, Below each window was an altar. They were dedicated a follows, beginning at the south end of the chapel:—
| 1. | S. Andrew and S. Mary Magdalene. | } | South bay. |
| 2. | S. John the Baptist and S. Margaret. | ||
| 3. | S. Thomas of Canterbury and S. Catherine. | ||
| 4. | S. Oswald and S. Lawrence. | } | Middle bay. |
| 5. | S. Cuthbert and S. Bede. | ||
| 6. | S. Martin. | ||
| 7. | S. Peter and S. Paul. | } | North bay. |
| 8. | S. Aidan and S. Helen. | ||
| 9. | S. Michael the Archangel. |
The rose window over the lancets of the middle bay is Wyatt's "restoration" of the original one. It consists of an outer circle of twenty-four and an inner circle of twelve radiating lights, the mullions of which are received on a foliated circle in the centre.
In the north wall of the chapel is a very fine window, known as the Joseph window, on account of the stained glass it originally contained, which illustrated the life-history of Joseph. It is a beautiful example of Early Decorated or geometrical Gothic, and is of six lights. There is an inner plane of tracery resting on clustered shafts, which is connected to the mullions of the window proper by through stones. The window occupies the complete width of the north end of the chapel. The painted glass which it once contained is thus described in the "Rites of Durham":
