There is one aspect of some of the Roman coast fortresses which shows that their builders were not influenced entirely by utilitarian ideas. This is the methodical and tasteful use of stones of different colours in such a way as to produce a pleasing species of colour decoration. The aim obviously was to break up the monotony of broad spaces of masonry, and possibly, also, to enhance their apparent size by multiplication of detail. The north wall of Richborough, although to some extent marred by rebuilding of some part of it, affords an illustration of this. Here we find dark brownish-red ironstone built into the wall in a way which reminds one of bands of chequer work. A Pevensey again, where the stones are cut with the regularity and precision of brickwork, large blocks of similar sandstone are employed in regular order at different heights in the walls and bastions. To the latter in addition to their decorative use they serve to tie in the outer skin of masonry to the inner rubble. [Illustration: FIG. 9. RICHBOROUGH, KENT. EXTERIOR OF NORTH WALL] 6. DUBRIS, DOVER A paper by Rev. Canon Puckle on Vestiges of Roman Dover was published some years ago in "Archaeologia Cantiana."[8] It was accompanied by a plan in which are set out the outlines of what are supposed to have been the limits of the Roman town or fortress of Dover. Although the outline is merely tentative and hypothetical, there is a certain plausibility about the suggested site and size of the castrum. It was situated, as is pointed out, quite away from the pharos, in the lowest part of the town, the present Market Square being approximately in the middle of the enclosure. The plan is roughly a parallelogram with certain irregularities on the north-west angle. On the top of the eastern and western heights of Dover a lighthouse was erected by the Romans for the guidance of ships into the narrow mouth of the river. Traces of that on the western heights still remain, or remained recently: whilst that on the eastern heights stands intact, one of the most remarkable and interesting pieces of Roman architecture now remaining in the kingdom. The Roman pharos at Dover consists of a strong and massive tower, hollow within, which rises to a height of 42 feet, having walls whose thickness varies from 12 feet at the base to about 7 feet at the top. The structure is not entirely of Roman workmanship, because in the thirteenth century certain additions were made to its outer walls. Doubtless its massive masonry was calculated to withstand the severe storms to which its exposed position on the lofty cliff subjected it. Whether employed for signalling purposes or as a lighthouse, this building was doubtless in such a position as to communicate with similar buildings on the coast of France, and with the lighthouse or signalling tower (it may have served in both capacities) at Richborough.