The nave, pictured on the left, is covered by a traditional barrel vault on transverse arches, whereas the side aisles, visible on the right, are covered by a groin-vault. This particular distribution, of barrel vault over the nave and groin-vault over the collaterals, is one of the common features of the Romanesque period.

• The groin vault is created by the intersection, at right angles, of two barrel vaults. The crest, or line where the two vaults meet, forms a pair of diagonal arches connecting the columns in opposite corners of the bay. We can see here the origins of the quadipartite vault of the gothic style as well as an early form of the bay.