During the Norman period monasticism prevailed, and almost all the large churches were conventual. These churches were always designed on the cruciform plan, and contained choir, nave, and north and south transept, each portion having side aisles, and the transepts usually only an eastern aisle. The small churches and side aisles were frequently vaulted, but the large churches appear to have been designed for wooden roofs. The details and ornaments of the style are often very elaborate, and invariably correspond with those in use in England at, or rather earlier than, the corresponding period. In the early examples, the design was very simple, and ornament was sparingly used; but as time advanced the style was gradually enriched, until towards the close of the period the ornament became very elaborate, especially in the arched heads of doorways, as at Kelso, Jedburgh, and Dunfermline. A common feature in Norman buildings was an arcade running round the walls below the windows. Almost every Norman structure of importance in Scotland contains this arcade, either in the interior or exterior, or both, and the caps and arches are generally elaborately and richly carved with ornaments. Here, and generally throughout Norman structures, the chevron or zig-zag enrichment is a characteristic feature. The other enrichments of the period in other countries consist of the billet, the bird’s beak, faceted sinkings, grotesque heads, rosettes, &c., all of which are found in the Scottish examples. The doorways are generally the points where the carving is richest, and it naturally followed that the doorways are often preserved where the other parts of the buildings are altered or rebuilt. The windows are always single, and simple in details. Some of the towers above enumerated are amongst the earliest examples of Norman work which survive. They contain some reminiscences of the early defensive purpose of such structures. They are extremely simple in design, being square on plan, and carried up, without break or buttress, to the parapet, where they were finished with a gabled roof, forming the saddleback arrangement still preserved in the tower at Muthill. The only break in the height is formed by string courses, which mark the unequal stories. A small wheel stair usually leads to the top. The doorway in some instances is placed several feet above the ground. Amongst these towers are to be found most of the small fragments which still survive of the extensive building works encouraged by David I. in the first half of the twelfth century. In the following descriptions the churches are arranged, as far as possible, in the order of their probable dates, commencing with the oldest and simplest, and continuing with the later and more elaborate examples. MARKINCH TOWER, FIFESHIRE.