The natural features of the Capitoline Hill could hardly have been more completely concealed than they are by the present situation of the buildings upon it, even if those buildings had been erected with the express purpose of changing the appearance of the hill. For the convent of Ara Cœli and the Palazzo Caffarelli, which occupy respectively the north-eastern and south-western summits of the hill, are comparatively low and unconspicuous, while the so-called Tabularium and above it the Palace of the Senator compose a lofty pile which nearly fills up the depression between these two heights. To the spectator looking at the Capitol from the Forum, the higher part of the hill appears to lie nearly in the centre, whereas in reality the shape is that of a double hill rising at each end. The north-eastern end is somewhat curved round towards the north, while the south-western approaches within 300 paces of the river. The whole core of the hill is formed of the harder volcanic tufa, a section of which may be plainly seen, composing the face of the low precipice now shown as the Tarpeian rock, and also in a courtyard surrounded by cottages, near the spot called Palazzaccio. This tufa was, as has been frequently mentioned, used as a building stone in the early ages of Rome before the lapis Gabinus, or Albanus (peperino) or the lapis Tiburtinus had been introduced. [Sidenote: Tarpeian Rock.] The Tarpeian Rock whence criminals were hurled, was, according to the older Italian topographers down to the time of Nardini, placed at the western edge of the hill towards the Tiber, where the Piazza Montanara now is. But Dureau de la Malle in the Mémoires de l’Académie for 1809, pointed out that this was inconsistent with the statements of Dionysius, who says that it was over the Forum, and that the executions took place in full view of all the people. This would seem to place it on the S.E. side towards the Palatine near S. Maria della Consolazione. Becker’s objection that the hill is less steep there than at the western edge, may be met by the fact that several large masses of rock are recorded to have fallen down from this spot, and therefore the face of the cliff is entirely changed. The further objection that the criminals would have fallen into the Vicus Jugarius, instead of which they ought, according to custom, to have been cast over the city walls, seems to rest on the assumption that criminals were always thrown over the walls, no proof of which has been adduced. Tradition is equally divided between the two localities, and therefore the passages of Dionysius above quoted must be held at present decisive in favour of the side towards the Palatine and Forum. [Sidenote: Thermæ of Constantine.]