The cloisters, which stood to the south-west of St. Peter's, are now almost wholly destroyed.--To the west of them is a large hall or gallery, known by the name of _la Salle des Chevaliers_. It is entered by two porches, one towards the north-west, the other towards the south-west[16], both full of architectural beauty and curiosity. I know of no authority for their date; but, from the great variety and richness of their ornaments, and the elegant taste displayed in the arrangement of these, I should suppose them to have been erected during the latter half of the twelfth century: one of the arches is unquestionably pointed, though the cusp of the arch is very obtuse. The slight sketch which accompanies this letter, represents a fragment of the inner door-way of the south-west porch, and may enable you to form your own judgment upon the subject. [Illustration: Sketch of fragment of inner door-way] The stones immediately over the entrance are joggled into each other, the key-stone having a joggle on either side.--I have not observed this peculiarity in any other specimen of Norman masonry.--Between these porches apartments, along the interior of which runs a cornice, supported by grotesque corbels, and under it a row of windows, now principally blocked up, disposed in triplets, a trefoil-headed window being placed between two that are semi-circular, as seen in the accompanying drawing. The date of the origin of the trefoil-headed arch has been much disputed: these perhaps are some of the earliest, and they are unquestionably coeval with the building. [Illustration: Ancient trefoil-headed Arches in Abbey of Jumieges]