_giallo antico_ columns and pilasters, which are supposed to have belonged to the triumphal arch of Trajan. They are so damaged in appearance, and so discoloured by the weather, that it is not easy, without close inspection, to tell the material of which they are composed. For pavements and the sheathing of interior walls _giallo antico_ was used more frequently than almost any other kind of marble; hence it is mostly found in fragments of thin slabs, with the old polish still glistening upon them. It is difficult to describe, so as to identify it, the species of marble known as _Africano_. It has a great variety of tints, ranging from the clearest white to the deepest black, through yellow and purple. Its texture is very compact and hard, frequently containing veins of quartz, which render it difficult to work. Its ancient name is _Marmor Chium_, for it was brought to Rome from a quarry on Mount Elias, the highest summit in the island of Chios--the modern Scio--which contested the honour of being the birthplace of Homer. It received its modern name of Africano, not from any connection with Africa, but from its dark colour. It enters pretty frequently into the decoration of the Roman churches, though it is rare to see it in large masses. It seems to have been much in fashion for pavements, of which many fragments may be seen among the ruins of Trajan's Forum. The side wall of the second chapel in the Church of Santa Maria della Pace in the Piazza Navona is sheathed with large slabs of remarkably fine Africano, "with edges bevelled like a rusticated basement." In the Belvedere Cortile in the Vatican is a portion of an ancient column of this marble, which is the most beautiful specimen in Rome; and the principal portal of the portico of St. Peter's is flanked by a pair of fluted Roman Ionic columns of Africano, which are the largest in the city.