ut what is most
remarkable is that there are also ridge-ribs, which are not usually
found before the thirteenth century, and it has been suggested[89] that
this is the earliest instance of their employment. There are also
wall-ribs, and these and the ridge-ribs are much thinner than the
groin-ribs, and consist of a single roll only.

[Illustration: VAULT OF THE NORTH TRANSEPT AISLE, TWELFTH CENTURY.]

=The South Transept= is narrower than the other by a yard, its width being
49 feet to the aisle wall (which, it should be noticed, has not been
rebuilt). Without the aisle the width is only 30 feet, but this is
partly due to the Perpendicular alterations. The end and west side of
this transept, which remain more or less as they were in Archbishop
Roger's day, resemble the corresponding walls of the other, yet with the
following differences. The roof-shafts on the west side are thinner here
than there, and are carried up to the required height in one piece,
unbroken save by the string-courses.

In connection with the attachment of shafts of any considerable height
to wall-surfaces in Archbishop Roger's work, it will be observed that
though the shafts (according to the general practice of masonry) are
usually made in short joints built in at the back, yet (as here) their
jointing sometimes does not harmonize with the coursing of the wall;
again (as in the old nave and north transept) the shafts of a cluster
are sometimes not worked all on the same stones.

To return to the differences of this transept from the other, the
roof-shafts over the inserted Perpendicular arch (which here obtrudes
into the triforium) descend no lower than the sill of the clearstorey.
Again, the thickening of the walls at the top is supported in the
south-west angle not by one shaft but by two, one of which stands on a
projecting strip of masonry that runs up the angle to the triforium. The
design of the eighteenth century monument against the south wall, to Mr.
Weddell of Newby, is taken from that of the choragic monument of
Lysicrates at Athens.

On the east side, which has been entirely remodelled in the
Perpendicular period, the bay next to the tower displays from the ground
to the triforium a plain surface broken only by a pointed doorway
surmounted by three cinquefoiled niches with ogee crocketed hoods. The
doorway retains its original doors with an ornamental iron scutcheon
over the keyhole. In their great strength, and in their treatme