But they are quite exceptional; and at North Witham both, and at Castle Rising one, are much later than the chancel arch. More frequently the chancel arch is given elaborate architectural treatment, with moulded orders and jamb-shafts, and occupies most of the width, and practically the whole height of the chancel behind. Early Saxon chancel arches were very narrow, as is the case at Escomb and Bradford on Avon--so narrow as to shut off the chancel from the nave. This may have been a survival of the primitive practice which kept, by means of curtains drawn round the canopy of the altar, the consecration of the sacred elements in the Eucharist from the public eye. All through the middle ages, it was customary during Lent to hang a curtain or Lenten veil across the chancel arch; and in many English churches hooks for its support may still be seen. A narrow chancel arch would be much more serviceable for this purpose than a wide one; and its persistent continuance through the twelfth century may perhaps be attributed to this usage. § 40. While, in the enlargement of a church, the nave was usually widened by the addition of aisles, the chancel was in most cases lengthened, and was often rebuilt entirely, in order to provide more room for the stalls of the quire. Thus, at Sandiacre in Derbyshire, the twelfth century nave and chancel arch were left untouched, but a splendid chancel was built in place of the old one during the fourteenth century. The screen which divided chancel from nave is gone; but nowhere can we appreciate better the practical separation between the parishioners' portion of the church, and that devoted to the clergy and quire, which, in churches like this, became almost as marked as in the monastic and larger collegiate churches. The lengthened chancel, forming a deep aisleless projection to the east of the building, was often treated with great architectural dignity. Nothing could be more beautiful, from their very simplicity of design, than the chancels of Mitford in Northumberland, or Burgh-next-Aylsham in Norfolk, with their row of lancet windows in the side walls, and the marked projection of their string-courses and buttresses. Later in the thirteenth century, the chancel of Houghton-le-Spring church, near Durham, gives us another example from the north of England of spacious planning, with light admitted through a row of splayed lancets. The chancel of the collegiate church of St Andrew, Bishop Auckland, enlarged about 1250 or rather later, underwent further alteration not long after, by the substitution of broader two-light openings for the narrower lancets, and of a large mullioned east window for a group of lancets at the east end. In Yorkshire, the chancel of West Heslerton, a simple aisleless church, was lengthened and lightened by a row of lancets not unlike those at Houghton-le-Spring. Further south, the nobility which long lancet windows in bays divided by projecting buttresses, and marked