The shafts throughout are single, and (in the sub-arches) detached, and the details generally are the same as in all Archbishop Roger's work. It is worthy of remark that the tympanum over the sub-arches is flush with the lower part of the wall, and that the comprising arches, with all the walling above them, are a plane in advance. The more natural plan would have been to make the comprising arch flush with the wall below, and to have set back the sub-arches and tympanum. In consequence of Archbishop Roger's arrangement the shafts of the comprising arch stand, not upon the sill of the triforium, but upon corbels, each of which carries two of them and also a roof-shaft[58] which forms with them a cluster. The clearstorey shows in the broad bay a stilted round arch, pierced, between two small blind lancets, and in the narrow bay three small blind lancets. These arches are not recessed or moulded, and are without hoods, as usual. Their piers, behind which is a passage, are square, and the impost moulding is continued as a string. The roof-shafts have a curious break in them at the impost-level of the triforium, where a face is carved upon them with a band above it. They are banded also by the impost-moulding of either storey, and by the upper string-course, and end in square-topped capitals a little short of the present roof. Throughout Archbishop Roger's church the roof was probably flat, or slightly coved as at Peterborough. The corbels from which the roof-shafts spring are moulded and finished off with scrolls, and are placed at the level of the string-course, which is undercut; but on either side of the tower-arches the shafts have been shortened to a point above the string, which has been made continuous beneath them, and instead of corbels they have grotesque heads carved upon their ends. Beyond the westernmost roof-shaft there is a further shaft, which at first sight seems to have been the beginning of another bay, but the round moulding which rises from it runs up vertically instead of curving over to form an arch.