sentences:  The similarities in the arcading, and in the two buildings' decorative patterns using a variety of motifs like chevron and nailhead, support the dating of the archways to about the same time as the chapter house, in the 12th century.The southern side of the carriage gateway is the most elaborate, with the archway having four courses of moulding.The postern gate has carved mouldings around the northern arch but is unvaulted and otherwise plain.