A specially French feature is the chevet, a group of apsidal chapels which were built round the apse itself, and which combined with it to make of the east end of a great cathedral a singularly rich and ornate composition. This feature, originating in Romanesque churches, was retained in France through the whole of the Gothic period, and a good example of it may be seen in the large Romanesque church of St. Sernin at Toulouse, which we illustrate (Fig. 169). The transepts were usually well marked. The nave arcades generally sprang from piers (Fig. 170), more rarely from columns. Arches are constantly met with recessed, _i.e._ in receding planes,[35] the first stage of progress towards a Gothic treatment, and are occasionally slightly moulded (Fig. 171). Western doorways are often highly enriched with sculpture; and the carving and sculpture generally, though often rude, are full of vitality. Towers occur, usually square, more rarely octagonal. Window-lights are frequently grouped two or more under one arch. Capitals of a basket-shape, and with a square abacus, often richly sculptured, are employed. [Illustration: FIG. 169.--CHURCH OF ST. SERNIN, TOULOUSE.] [Illustration: FIG. 170.--NAVE ARCADE AT ST. SERNIN, TOULOUSE.] [Illustration: FIG. 171.--ARCHES IN RECEDING PLANES AT ST. SERNIN, TOULOUSE.] In Normandy, and generally in the North of France, round-arched architecture was excellently carried out, and churches remarkable both for their extent and their great dignity and solidity were erected. Generally speaking, however, Norman architecture, especially as met with in Normandy itself, is less ornate than the Romanesque of Southern France; in fact some of the best examples seem to suffer from a deficiency of ornament. The large and well-known churches at Caen, St. Etienne, otherwise the Abbaye aux Hommes--interesting to Englishmen as having been founded by William the Conqueror immediately after the Conquest--and the Trinité, or Abbaye aux Dames, are excellent examples of early Norman architecture, but the student must not forget that additions have been made to them, which, if they add to their beauty, at the same time alter their character. For example, in St. Etienne, the upper part of the western towers and the fine spires with which they are crowned were built subsequent to the original structure, as was also, in all probability, the chevet, or eastern limb. It seems probable also that the vaulting may not be what was contemplated in the original plan.