Although the plan followed fixed and familiar lines, there were no fixed dimensions to the castle. The mount was intended to bear the strong tower or donjon: within the bailey were the ordinary lodgings of the garrison, and such domestic buildings as might be needed. The bailey, which inclined, on the whole, to be oval in form, was surrounded by a low earthen bank, outside which was a dry ditch of more or less depth, with a parapet or counterscarp on the further side. The mount was surrounded by its own ditch, which was joined at two points by the main ditch on the side next the bailey. The entrance to the castle was at the end of the bailey, opposite the mount. These dispositions might vary: the mount might be within the enclosure, even, as at Pickering, in its centre, and the position of the entrance might be different, if the site required it. There might be more than one bailey, and these might be set side by side, divided by an intermediate ditch, as on the fairly level site at Clun (43), or end on end, as on the ridge at Montgomery, or a small bailey might project as a kind of outwork common to mount and bailey alike.[49] The usual arrangement, however, was as described. The mount might be of any height, of enormous proportions, as at Thetford, or of more modest size, as at Brecon or Trecastle. It was usually entirely artificial; but positions were sometimes chosen in which the ground afforded natural help. The mount, for example, at Hedingham in Essex, on the levelled top of which the later square donjon was built, appears to be partly natural; while the great mount at Mount Bures, not many miles away, is wholly artificial. The bailey, again, might vary much in size. It might have a very large area, as at Lincoln and Tutbury, a moderate area, as at Warkworth (49) or Durham (199); or it might be small and compact, as at Trecastle (44). There are many cases, as at Clifford’s hill, near Northampton, where the mount is found by itself: in such instances, the bailey may have disappeared as the result of local cultivation, and only the more important part of the earthworks may have been left. But it is also probable that here and there the fortified mount with the tower on its summit would be all that was needed, and that the absence of a large garrison would render a bailey unnecessary. The size of the bailey, in any case, would depend upon the importance of the position and the size of the garrison required. [Illustration: Trecastle; Plan] [Illustration: Castle of Rennes: from Bayeux Tapestry]