In spite, however, of this rather considerable elevation, which, reckoning for dilapidation at the top and the portion buried under ground, cannot have been much less than thirty feet, it seems nearly certain that the Roman houses in Britain had no upper stories, and that all the rooms were on the ground floor. No traces of a staircase have ever been found, and all the fragments which are met with, indicate that the rooms were open to the roof. These roofs appear to have been of substantial construction, and were probably supported on a strong frame of woodwork. The common coverings of the Roman houses of this island consisted of large square tiles with strongly flanged edges, and these tiles being joined side to side, a curved tile forming the half of a cylinder was placed over the flanges of the two tiles which joined, thus holding them together, and at the same time protecting the juncture so that rain could not pass through it. These tiles, and the manner in which they were arranged, will be understood by our figures, (_pl_. IV., _figs._ 1, 2, 3). The Roman houses were also very commonly roofed with slates, or rather flags, and this appears to have been the more usual description of roofing in Uriconium. These roof-flags are found scattered about abundantly on the floors, sometimes unbroken. They are formed of a micaceous laminated sandstone, which is found on the edge of the north Staffordshire and Shropshire coalfield, at no great distance from Wroxeter, and must have produced a glittering appearance in the sunshine. Their form is represented in our cut, (_pl_. IV., _fig._ 5); it was that of an elongated hexagon, with a hole at one end, through which an iron nail was passed to fix it to the wooden frame-work. The nail is often found still remaining in the hole. These flags, which are very thick and heavy, were placed to lap over each other, and thus formed a roof in lozenges or diamonds, as represented in _fig._ 6. Slates forming one half of the hexagon (_fig._ 4), were placed at the top of the roof, so as to make a strictly horizontal line. It is a curious circumstance, that in the illuminations of Anglo-Saxon manuscripts we find roofs of houses which evidently represent both these methods, and which appear, therefore, to have been continued long after the Roman period. In fact they are still used in Yorkshire, and perhaps in other counties, and have been used very recently on the Welsh border. In the towns which were the head-quarters of a legion, as at Caerleon, Chester, and York, or which had been occupied for some length of time by legionary detachments, we often find the name and number of the legion stamped on the roof-tiles. These roof-tiles were frequently used for other purposes. They are sometimes employed in the string-courses in walls, when the builders appear to have run short of the ordinary square tiles or flat bricks; and they are still more frequently used to form the beds