On January 11th last (1899), while workmen under the directions of Commendatore Boni were removing the rough post-Imperial “selce,” or paving-stones, in front of the church of S. Adriano and some fifteen yards immediately east of the Arch of Severus, there came to light a pavement of black marble, rhomboidal-trapezoid in shape, and framed on three of its sides with blocks of travertine. These blocks were found to be grooved on the southern and eastern sides, and from the groove or “incassatura,” on the former of these sides, projected to the height of two feet, three contiguous slabs of white marble. They had been noticed two or three days before. It now became evident that they had been appropriated from some late imperial building and utilised in order to act as substitute for some older fence which had isolated and protected this remarkable black pavement.