§ 38. It should not be forgotten that a porch was occasionally used as the foundation of a tower. There is a good example of a northern porch tower at Cromhall in Gloucestershire and of a southern porch tower at Norbury in Derbyshire; but the finest instance is probably the south tower and spire of Donington in south Lincolnshire. The south tower at Fowey in Cornwall is another striking example. It was merely custom and tradition which made the west tower a nearly invariable feature in most districts of England during the greater part of the middle ages. It is obvious that the position of the tower in the plan is elastic, and we find it, not merely over the crossing of the transepts, or over a side porch, or at the extremity of a transept, or as an upward extension of a transeptal chapel, but also in a position detached from the church. The beautiful tower of West Walton in Norfolk is at the entrance to the churchyard, its ground story forming the gateway. In examples like this--Fleet and Tydd St Giles, in the same neighbourhood, stand apart in their churchyards--the insecure nature of the soil probably made the building of a bell-tower in direct attachment to the church unsafe, and therefore undesirable. § 39. The Norman chancel in England was rectangular in the majority of cases. It was also narrower than the nave, from which it was divided by an arch. Such arches are almost invariably, until the middle of the twelfth century, round-headed, and are usually low in elevation. Their character and width, however, vary greatly. At North Witham the archway is low and narrow, and the arch is unmoulded; decoration is confined to the impost-blocks from which it springs. A wide space of wall is left on either side of the opening. When in the thirteenth century the chancel was enlarged, these spaces were pierced with wide pointed openings, presumably in order to give a better view of the altar from the body of the church. In north Yorkshire there are a large number of similar chancel arches, the narrowness and plainness of which have sometimes induced antiquaries to class them as Saxon. Saxon in affinity they may well be; but at Scawton on the Hambleton hills, where one of them occurs, and the wall on either side is pierced with late Norman openings, we know that the church was built in 1146. At Bracebridge, near Lincoln, where there is a fairly lofty and narrow chancel arch of early character and uncertain date, there are openings, apparently later than the rest of the work, at the sides. These openings are not carried down to the ground in any of the cases mentioned; and there were probably altars against the wall below them, as was certainly the case at Castle Rising in Norfolk, and Avening in Gloucestershire, where towers occur between nave and chancel. Were such openings invariable, or were they even contemporary with the chancel arch, we might see in them a survival of the triple-arched screen wall of early Saxon times.