l evolution of the cruciform plan with central tower. It must
be noted once more that to the cruciform plan the central tower built on
piers and arches is essential. It is possible, as in the Gloucestershire
churches of Almondsbury and Avening, to pierce the north and south walls
of a tower and add transeptal chapels: the plan will have a cruciform
appearance, but will still be only an elongated plan with lateral
additions. It is possible, in a church where there is no central tower
at all, to extend the side walls at right angles north and south, and
so form transepts; but here again the transepts have no structural
reference to a central point in the plan, but are mere widenings of the
nave or aisles. The thirteenth century aisleless churches of Potterne,
in Wiltshire, and Acton Burnell, in Shropshire, are both cruciform in
plan. The church at Potterne was planned throughout with reference to
the crossing of transepts, nave, and quire, above which its central
tower rose: the tower space is the central point of the whole. But, at
Acton Burnell, there is no central tower or space: the body of the
church consists of a long aisleless nave and an aisleless chancel
beyond; and the transeptal chapels are simply stuck on, as it were, to
the eastern part of either wall of the nave. This is at once noticeable
in elevation, when the chapels are seen to be mere excrescences, with
roofs lower than the nave. Moreover, where there is a true central
crossing, with a tower above, such as we find in almost all our
cathedrals, a transept on either side is necessary for the support of
the tower. The transepts need not be wholly symmetrical, although in
most cases they are; but they must be there. On the other hand, where
there is no central tower, and the crossing is merely apparent, symmetry
of treatment is quite unnecessary. While there are two transeptal
chapels of similar size at Acton Burnell, or at Achurch in
Northamptonshire, there are far more instances in which a less regular
treatment was adopted. Thus, at Childs Wickham in Gloucestershire, and
Montacute in Somerset, there is only one transeptal chapel, in each case
on the north side. At Corbridge in Northumberland, transeptal chapels,
extended outwards from the aisle walls, are of different lengths. At
Medbourne in Leicestershire, a long aisleless transeptal chapel was
built out from the north side of the nave in the thirteenth century.
Within the next fifty years a south chapel