Fig. 69.—Amiens, Cathedral.
Nevertheless it may have been a feeling on the part of the builders that there was a lack of abutment to the west of the keystone which led to the introduction of one or more short ribs at this point in a number of chevets of various dates throughout the Gothic era. Thus in the apse of Saint Étienne at Caen [(Fig. 70)],[381] of Saint Trophîme at Arles, and of the cathedral of Notre Dame at Mantes, a single rib runs out from the keystone of the chevet to that of the apsidal arch. ([Plate II-h.]). Nor was this rib a continuation of a ridge rib in the choir, for in the instances just cited no such rib was employed. One is to be seen in a number of churches, among them such widely separated examples as San Saturnino at Pamplona,[382] Westminster Abbey,[383] and Saint Alpin at Chalons-sur-Marne.[384] All of these churches have diagonal-ribbed chevets, but there are instances of a short rib running to the apsidal arch even where the vault is of the buttressing ribbed type, as for example in the cathedral of Barcelona,[385] where it would seem to have been used to subdivide the great triangular transverse cell of the vault even more than to provide further apparent abutment for the other radiants ([Plate II-i.]). Even in chevets of the first type with ribs radiating from the keystone of the apsidal arch, a rib is occasionally added in the bay preceding this vault, as for example in Saint Pierre-le-Guillard at Bourges (fifteenth century vaulting), where this short rib runs out only to the crown of the six-part vault with which the last bay of the choir is covered ([Plate II-j.]). Occasionally, too, a church like the cathedral of Moulins (Allier) (1468-1508), with a ridge rib the length of the choir, is terminated by a chevet with radiating ribs which thus receive apparent abutment at their keystone ([Plate II-k.]).
Fig. 70.—Caen, Saint Étienne.