by roofs which sloped up from their eaves against the wall that rose
above the nave arcades. Internally the ceiling to these was a simple
groined vault supported by transverse arches.

Immediately above the vault of the aisles was the gallery of the
triforium. This was lighted throughout by small external round-headed
windows, some of which may still be seen embedded in the walls. The
aisles and ambulatory of the chancel were treated by the same methods.
In the triforium gallery, above the transverse arches of the aisles,
were other semicircular arches. These served a double purpose: they
acted as supports to the timber framework of the aisle roofs, and also
as a means of buttressing the upper part of the nave walling in which
the clerestory windows were placed. Such other buttresses as there had
been were broad and flat, with but little projection from the surface
of the wall. The windows throughout the building up to about the end
of the twelfth century were small in comparison with some of those
which were inserted at various times afterwards.

[Illustration: VIEW THROUGH THE SOUTH TRIFORIUM OF THE NAVE FROM THE
SOUTH-WEST TOWER. _From a photograph by Mr. F. Bund_.]

It has been remarked that the termination of the early chancel towards
the east was an apse, and that round this was carried the north and
south choir aisles in the form of a continuous ambulatory. From this
enclosing aisle--a semi-circle itself in form--three chapels were
projected, each with a semicircular apsidal termination. The central
one of the three was the lady-chapel. This consisted then of the three
western bays only of the present chapel. The lady-chapel was added
about eighty years after the early part of the nave had been built,
and has since been much altered.