The =Porch= and =Parvise= beneath the middle arch was inserted, as has been previously stated, as a support to the two great piers. It is vaulted in two bays, the first being of the same dimensions as the inner width of the portico; the western bay (of the same size) thus reaches beyond the two great piers, and the corner turrets and buttresses in all project about seven feet. This gives a very substantial support to the piers. The whole composition is very fine, and quite worthy of the great portico to which it is an adjunct. It must be left to each spectator to decide for himself if it improves or diminishes the effect of the whole. It is of late Decorated date, highly enriched with profuse carving. The staircase turrets, as well as the great window are embattled. Possibly there may have been pinnacles now lost. The spaces north and south, and within the portico, have tracery on the walls similar to the window. The groining is very fine. One of the central bosses has a representation of the Trinity. The Father is represented as the Ancient of Days, with a Dove for the Holy Spirit above the shoulder, and the figure of the Saviour on the Cross in front. Freemasons are recommended to look for a special symbol which they alone can understand and appreciate. The floor of the portico is paved with gravestones, some apparently in their original position. This place was at one time appropriated as a burial place for the Minor Canons.[23] Some of the stones, however, are of mediaeval date, and it can be seen where the brasses have been wrenched from them: some of these have been used again for later inscriptions. One stone bears an incised cross originally filled with some coloured composition. Some of the marble wall-shafts had fallen, and their places had been filled by stone substitutes. Others had been cheaply replaced by wood. The stone shafts still remain, but the wooden imitations have all been replaced by new marble which was specially quarried for this reconstruction.