As in England generally, the architecture of the older buildings of all three classes has been affected to a greater or less degree by the nature of the building materials most easily accessible. Throughout the northern chalk area of the county the Totternhoe stone of Bedfordshire and the northern flanks of Hertfordshire was largely employed in church building, both for inside and outside work, to the latter of which it is but ill suited. Flint--in the better class of work “faced” or “dressed” by fracture so as to present a flattened outer face--was also very extensively used. The Norman builders of the tower of St Albans found, however, a quarry ready to their hands in the adjacent walls of Verulam, and we accordingly find this part of the structure made almost entirely of the characteristic Roman bricks or tiles. Contemporaneous brick was also locally used to a very considerable extent even in the chalk districts; and in the north-western part of the county there are numerous beautiful examples of Tudor brick chimneys, as at Water End. Timber in the old days was, however, much cheaper than bricks, and we consequently find many of the older buildings--especially cottages--constructed of a framework of wood, arranged in the fashion of a net, with the large “meshes” filled in with brick. This type of work is locally known as brick and studding and to the architect as half-timbered work. Other buildings were largely constructed of a wooden framework overlain with lath-and-plaster work. Many of the churches built of flint or Totternhoe stone have their angles or quoins made of harder material; in many instances of stone apparently from Northamptonshire, but in other cases of Roman brick; similar materials being also used in the arches of some of the churches. [Illustration: St Peter’s, Tewin] A large number of Hertfordshire churches have relatively low battlemented towers, frequently with a short spire or steeple in the centre as at Tewin, or a turret in one corner. Kensworth is an example of such a battlemented tower without either spire or turret; St Mary’s, Hitchin, Tring, Northchurch, Barnet, Bushey, King’s Walden, Cheshunt, and Watford are examples of towers with a turret in one angle, while at Ashwell there are turrets in all four corners. Some of the smaller churches, like St Michael’s, St Albans, originally had no aisles. Clothall church is peculiar in that the roof of the tower forms a four-sided cone; while the roof of the church at Sarratt is equally unique in being saddle-backed, that is to say, having a ridge running at right angles to that of the roof of the nave and chancel. [Illustration: St Mary’s, Cheshunt]