during some prehistoric eruption, and stopped short here, forming the quarries on the left side of the road which supply most of the paving-stone of modern Rome.  The Appian Way was here lowered several feet below the original level, in order to diminish the acclivity; and the mausoleum was consequently raised upon a substructure of unequal height corresponding with the inclination of the plane of ascent.  It was originally cased with marble slabs, but these were stripped off during the middle ages for making lime; and Pope Clement XII. completed the devastation by removing large blocks which formed the basement, in order to construct the picturesque fountain of Trevi.  A large portion of the Doric marble frieze, however, still remains, on which are sculptured bas-reliefs of rams’ heads, festooned with garlands of flowers.  Usually the bas-reliefs are supposed to represent bulls’ heads; and the name of Capo de Bove (the “head of the ox"), by which the monument has long been known to the common people, is said to be derived from these ornaments.  But a careful examination will convince any one that they are in reality rams’ heads; and the vulgar name of the tomb was obviously borrowed from the armorial bearings of the Gaetani family, consisting of an ox’s head, affixed prominently upon it when it served them as a fortress in the thirteenth century.  Pope Boniface VIII., a member of this family, added the curious battlements at the top, which seem so slight and airy in comparison with the severe solidity of the rest of the structure, and are but a poor substitute for the massive conical roof which originally covered the tomb.  Nature has done her utmost for nigh two thousand years to bring back this monument to her own bosom, but she has been foiled in all her attempts,—­the travertine blocks of its exterior, though fitted to each other without cement, being as smooth and even in their courses of masonry as when first constructed, and almost as free from weather-stains as if they had newly been taken from the quarry.  Only on the broad summit, where medieval Vandals broke down the noble pile and desecrated it by their own inferior workmanship, has nature been able to effect a lodgment; and in the breaches of this fortress, which is but a thing of yesterday as compared with the monument, and yet is far more ruinous, she has planted bushes, trees, and thick festoons of ivy, as if laying her quiet finger upon the angry passions of man, and obliterating the memory of his evil deeds by her own fair and smiling growth.

The sepulchral vault in the interior was not opened till the time of Paul III., about 1540, when a beautiful marble sarcophagus, adorned with bas-reliefs of the chase, was found in it, which is supposed to be that which stands at the present day in the court of the Palazzo Farnese.  This is likely to be true, for it is well known that this Pope, who was a member of the Farnese family, unscrupulously despoiled ancient Rome of many of its finest works of art in order to