case are very regular; and the new arcades were probably built, at any rate in part, on older foundations. These naves reach the extent, unusual in a parish church, of seven bays. The nave of Norham is of five bays. Melbourne has five bays, but the plan of the church was as exceptional at the west as at the east end. Western towers were planned, but not completed, at the end of either aisle: this feature, probably imitated from Southwell minster, was also contemplated at Bakewell in Derbyshire. Between the towers was an extra western bay of the nave, divided into two stories, the lower forming a vaulted return aisle, the upper forming a gallery. There are only four bays at Sherburn, but here the aisles were continued as far as the western face of the tower. The tower is thus engaged within the aisles, and its vaulted ground floor forms, like the western bay at Melbourne, a return to them. Sec. 43. But, when the question of adding aisles to a church arose, the builders were met by the difficulty that the church was wanted constantly for service. The taking down of the walls and the building of new arcades interfered with this necessary use of the fabric. In our own day a congregation, driven out by builders or restorers, can resort to a school room or mission room. In the middle ages, these alternatives were unknown; and the church was positively indispensable. With this in view, the builders were obliged to add their aisles without touching more of the main fabric than they could help. Usually, then, they took the length of the existing aisleless building for the length of their aisles. They then set out the aisles upon either side of the church, building the outer walls, and dividing them into bays by external buttresses. Then, opposite each buttress, they proceeded to break through the walls of the church. Leaving a piece of the old wall to serve as a footing for each column, they built up the columns in the thickness of the wall, the masonry being gradually removed as each rose in height. The arches were made in the same way, the wall being removed by degrees until the two sides of each arch met at the key-stone. The aisles were then roofed, and, finally, the masses of wall which still remained beneath each arch were broken down, and the nave and aisles thrown into one. The old masonry could be removed through the doorways of the aisles; and sometimes one of the end walls of either aisle was left unbuilt to the last, so that the masons could have free entrance for new, and exit for old, material. The old walls of the nave, above the columns and arches, were left untouched. In this way the upper parts of the walls of several Saxon naves--more, probably, than we have opportunity of discovering--remain to us. The north wall at Geddington in Northamptonshire is the most striking instance. The practice was so common as to be general. In hundreds of country churches the plinths on