Though the three eastern bays (still on the north side) are chiefly Decorated, portions of Archbishop Roger's work have been retained or used again. Thus the fourth column from the west is his, and perhaps the fifth up to the abacus, which is convex and of limestone. The respond against the east wall is of his pattern, but it has not the circular plinth, and the capital is of limestone, has the abacus moulded with rounds upon the edge, and is covered with delicate foliage in the Decorated manner. In these arches the lower order has exactly the same mouldings as in the western bays, and is of gritstone, while the upper order is of limestone, and has fillets upon the larger mouldings. It would seem, therefore, that the later builders have used the original archivolts again, and have merely added another order or orders over it. The plane of the wall above, indeed, is brought forward to the face of Archbishop Roger's vaulting-shafts: yet without being really thickened, since it is set back from his wall on the exterior. At the junction of the old vaulting-shafts with the additional order of the first Decorated arch the later builders have carved a group of grotesque faces. In each bay of the Decorated triforium there is a round arch filled with tracery consisting of three round-headed and trefoil lights with two circles enclosing trefoils above them; and on either side of this arch (but on one three only, in the first of the side bays) is a sunk lancet panel enclosing a pointed arch impaling a trefoil. The clearstorey has a second plane of tracery, a feature not very common in England. The vaulting-shafts are in clusters of three and are filleted, and the string-course below the triforium is not carried round them. Each cluster springs from a semicircular corbel resting on a head, and has its capitals enriched with foliage. The last pendentive of the vaulting rests on a single shaft springing directly from a head-corbel. The string-courses are not of the same pattern with those on the older bays. [Illustration: THE NORTH SIDE OF THE CHOIR. (Junction of Transitional and Decorated work.)]