These mosaics must have been drawn out on the levelled beds prepared to receive them by the master artist and filled in by him and his assistants. The preparation for such a floor is made clear in the description of a London mosaic found in 1785: “This pavement, as well as most of the rest, was laid in three distinct beds; the lowest very coarse, about 3 in. thick, and mixed with large pebbles; the second of fine mortar, very hard and reddish in colour, from having been mixed with powdered brick; this was about 1 in. in thickness, and upon it the bricks [tesseræ] were embedded in fine white cement” (_Archæol._, vol. viii.). The Bacchus pavement described before “was bedded on a layer of brickdust and lime of about an inch.” Powdered brick (tile) and lime made a strong cement which would finish perfectly smoothly and provide an inviting surface to draw and work upon. Several mosaics while not quite plain were simpler in design and perhaps coarser in execution than those already described. A star-shaped fragment found in Bishopsgate Street, illustrated by Roach Smith, was of black and white tesseræ. It was probably the central panel of a floor, as Roach Smith said. A mosaic found at Lincoln had a similar star-shaped panel at the centre. About 1840 a tessellated pavement was found in Bishopsgate-Within “of black and white tesseræ in squares and diamonds” (_V.C.H._). In Bush Lane “a pavement of white tesseræ” is recorded. On the site of the Guildhall “irregular cubes of dark-grey slate and white marble” were found (_Journal B.A.A._ xix.). Another pavement, found in Lombard Street in 1785, was “composed of pieces of black and white stone one-third of an inch square, probably deposited in regular order” (_Archæol._ viii.). These black and white mosaics were doubtless like the counter-changed patterns found at Wroxeter, Silchester, etc. At the latter the Christian church had a square space for the altar paved in this way. Several years ago I drew a fragment of an identical design at Lincoln. This was probably a fourth-century fashion. The others may be a little earlier generally, but they overlapped into the Christian period. Many floors have been found in London which were wholly of coarse tesseræ of red, or of a few simple colours accidentally distributed. One of these is described as of irregular tesseræ about 2 in. by 1½ in., mostly red, but some black and white. A room 17½ ft. by 14 ft., in Leadenhall Street, had coarse tesseræ red, black and white, 1¼ in. square, and a similar floor “of red bricks about an inch square with a few black ones and white stones” was found in Lombard Street. Some floors found at Silchester had circular and polygonal tiles used with mosaic cubes filling up the interspaces. At Bath, if I recollect aright, there are fragments of pleasant floors in which larger irregular pieces of marble are set here and there in a floor mainly of large red tesseræ.