[427] If Signor Rivoira is correct in his attribution of this ambulatory to the third quarter of the eleventh century (Rivoira, I, pp. 222, 223), it affords not only an extremely early example of the straight ribbed type but an instance of a ribbed vaulted ambulatory of large size antedating that at Morienval by half a century. I am not prepared to accept this early date. The general elevation of the piers and ribs, the geographical situation of the church, the lack of any similarly vaulted ambulatories in the fifty years following its construction and the very form of the vaults, which may easily have once been of the groined type to be seen in the gallery of Santo Stefano at Verona with ribs added at a later date or reconstruction (note lower imposts of diagonal ribs and expanding soffits of transverse arches like those at Verona) together with many other details a discussion of which the limits of this paper forbids, make it seem most improbable that this ambulatory dates from 1049-1078. As a matter of fact, the date is of little importance in the present connection, since it is the type of vault employed with which this study is largely concerned. [428] Plan and interior view in Moore, pp. 72, 73, Figs. 26, 27. [429] Plan in Moore, p. 83, Fig. 34. [430] This may be plainly seen at the cathedral of Tournai (Fig. 85). [431] Moore, Mediaeval Church Architecture of England, p. 96, Fig. 82 and pl. XV, opp. p. 104. [432] Crypt illustrated in Moore, Mediaeval Church Architecture of England, p. 94, Fig. 80, Trinity chapel, p. 103 Fig. 86 and pi. XIV. opp. same page. [433] See Moore, Mediaeval Church Architecture of England, pp. 94-95. [434] See p. 99 for theory regarding this. [435] Moore, Mediaeval Church Architecture of England, pl. XV, opp. p. 104. [436] Moore, Mediaeval Church Architecture of England, pl. XIV, opp. p. 103. [437] Ambulatories vaulted in a similar manner appear in Saint Sauveur at Bruges, the Groote Kerk at Breda, the cathedral of Burgos, the church at Gonesse (Seine-et-Oise) (plan in Enlart, I, p. 486, Fig. 233) etc. Also, in Magdeburg Cath. (Hartung I, pl. 16), there is an instance in which the intermediate rib is shortened evidently to admit the greatest possible amount of light. [438] This is also a church employing the lancet type of window common in Normandy and England and the subdivision of the ambulatory thus made possible windows of general lancet shape. Furthermore, it carried the subdivision of the triforium arcade into the clerestory above. (For a large photograph of this ambulatory see Gurlitt, pl. 84). [439] Plan in Moore, p. 83, Fig. 34. [440] Similar vaults appear at Coutances Cath., outer ambulatory, Utrecht Cath. (ridge ribs added), Malmo, Ch., and Lagny, Ab. Ch. (illustrated in Lenoir, part II, p. 207). [441] Plan in Enlart, I, p. 505, Fig. 244.