The earliest and most general ornament is the chevron or zig-zag, which is frequently found doubled, trebled and quadrupled. The next most common form is the beak-head, consisting of a hollow and large round. In the hollow are placed heads of beasts or birds whose tongues or beaks encircle the round. On the west doorway of Iffley church, Oxford, are many of these beak-heads extending the whole length of the jamb down to the base moulding. They also figure prominently among the ornamentations of the hospital church of S. Cross, near Winchester. The zig-zag moulding is very common on Norman churches and is so easily recognised that no further description is needed here. The less prominent decorations of Norman mouldings include the alternate billet, the double cone, and the lozenge, together with an immense number of others less commonly found. [Side note: Windows.] The Early Norman window was little better than a narrow slit finished with a plain semi-circular head, and was generally only a few inches wide. They were, it is believed, filled with oiled linen and the sides of the aperture were splayed towards the interior. Later in the period, the windows were enriched by the zig-zag and other mouldings and at a still later period an improvement was made by inserting nook-shafts in the jambs similar to those in doorways. [Illustration: A Late Norman Parish Church. Castle Rising, Norfolk. _Drawn by Gordon Home._] The towers of Norman churches often show windows of two lights separated by a central shaft, all enclosed under a large semi-circular arch, the spandrel of which is rarely pierced. Plain circular windows of small dimensions are sometimes found in other positions and in churches of later date, and occasionally in gable walls. Larger windows of the same form, with small shafts radiating from the centre and connected at the circumference by semi-circular or trefoiled arches, are also found as at Barfreston church, Kent, where there is a fine example. [Side note: Doorways.] Norman doorways are found in great numbers and variety, even in churches which present no other features in this style. The most usual form consists of a semi-circular-headed aperture with a hood-mould springing from plain square-edged jambs. Frequently, however, the doorways are recessed, having a nook-shaft in the angle formed by a recession from the capital, in which case it presents two soffits and two faces, besides the hood-moulds. The depth of these doorways is largely due to the great thickness of the walls usual in buildings of this period, but in many cases that portion of the wall in which the entrance is inserted is made to project forward beyond the general face, which projection is finished either with plain horizontal capping, or a high-pitched gable. [Illustration: _West Doorway Rochester Cathedral_ Duncan Moul.]