Upon the summit and occupying the centre, as a rule, a wooden castle was erected known as the "bretasche," and varying in size and accommodation according to the available space. We may safely infer that the height of the bretasche was not less than two stories, and this, added to the elevation of the mound which occasionally reached to 60 feet, would afford a coign of vantage for a view over the whole area below. Upon the outer edge of the fosse a vallum occurs in many examples, thus still further adding to the depth of the defence and giving increased height to the counterscarp; it also afforded a means for erecting a palisading of stakes if advisable. To afford ingress and egress to the fort a narrow flying bridge of wood was erected reaching from the top of the mound to the outer edge of the fosse. [Illustration: CLIFFORD'S CASTLE, NORTHANTS.] Such was the method of construction of the simplest form of this type, of which Bures Mount in Essex, The Mount, Caerleon, and Clifford's Castle, Northamptonshire, are examples; but it is extremely questionable even if these cited cases were made without an accompanying bailey, although no traces can now be discerned. The accommodation would be so extremely limited, and the danger of starvation to the garrison so imminent, seeing that no room could be afforded for any cattle or sheep upon the motte, that, unless intended to be of a temporary nature or hastily raised in an emergency, we are justified in assuming that these forts, of which not very many occur, are in an incomplete condition. _Clifford's Castle_, at Little Houghton, three miles east of Northampton, is an example of the Motte and Fosse; it is one of those defending the valley of the river Nen--Earl's Barton and Wollaston being similar companion defences. The hill is of large circumference, presenting imposing proportions, and may be compared with important works like those at Ongar and Pleshey in Essex, or with Thetford in Norfolk. It rises to a height of over 50 feet above its surroundings, and lies upon part of a small natural ridge. A ditch surrounds the base, the ballast from which was taken to the top of the hill in order to increase the height; the summit there, however, is level. In order to increase the efficiency of the fosse it was converted into a moat, water being admitted from the adjacent river. At the present time no traces whatever of a bailey are discernible, nor of any enclosure with masonry walls. This does not prove that these additions have never existed; the natural place for them would be upon the eastern side where high ground is situated, and if they have been built at any period they would present features similar to those at Thurnham in Kent. The summit of the mound would in that case be reached by a flying bridge of wood.