Let us look more closely into these earthworks in their perfect form, the class (_e_) of the Earthwork Committee's list. They consist, when fully preserved, of an artificial hillock, 20, 30, 40, or in some rare instances 100 feet high. The hillock carried a breastwork of earth round the top, which in many cases is still preserved; this breastwork enclosed a small court, sometimes only 30 feet in diameter, in rare cases as large as half an acre; it must have been crowned by a stockade of timber, and the representations in the Bayeux Tapestry would lead us to think that it always enclosed a wooden tower.[4] As a rule the hillock is round, but it is not unfrequently oval, and occasionally square. The base of the hillock is surrounded by a ditch. Below the hillock is a court, much larger than the small space enclosed on the top of the mount. It also has been surrounded by a ditch, which joins the ditch of the mount, and thus encloses the whole fortification. The court is defended by earthen banks, both on the scarp and counterscarp of the ditch, and these banks of course had also their timber stockades, the remains of which have sometimes been found on excavation.[5] [Illustration: FIG. 1.--TYPICAL MOTTE-CASTLES. Topcliffe, Yorks. Laughton-en-le-Morthen, Yorks. Anstey, Herts. Dingestow, Monmouth. Hedingham, Essex.] These are the main features of the earthworks in question. Some variations may be noticed. The ditch is not invariably carried all round the hillock, occasionally it is not continued between the hillock and the court.[6] Sometimes the length of the ditch separating the hillock from the court is at a higher level than the main ditch.[7] Often the ditches were evidently dry from the first, but not infrequently they are wet, and sometimes vestiges of the arrangements for feeding them are still apparent. The hillock is not invariably artificial; often it is a natural hill scarped into a conical shape; sometimes an isolated rock is made use of to serve as a citadel, which saved much spade-work. The shape of the court is very variable: it may be square or oblong, with greatly rounded corners, or it may be oval, or semilunar, or triangular; a very common form is the bean-shaped. The area covered by these fortifications is much more uniform; one of the features contrasting them most strongly with the great prehistoric "camps" of southern England is their comparatively small size. We know of only one (Skipsea) in which the bailey covers as much as eight acres; in by far the greater number the whole area included in the hillock, court, and ditches does not exceed three acres, and often it is not more than one and a half.[8]