plished by the Christians. It has been said that the catacombs were in part the work of the heathen, and that the Christians made use of excavations which they found ready to their hand. Such and other similar assertions have been put forward with great confidence; but there is one overwhelming and complete answer to all such doubts,—a visit to the catacombs themselves. No skepticism can stand against such arguments as are presented there. Every pathway is distinctly the work of Christian hands; the whole subterranean city is filled with a host of the Christian dead. But there are other convincing proofs of the character of their makers. These are of a curiously simple description, and are due chiefly to the investigations of late years. Nine tenths of the catacombs now known are cut through one of the volcanic rocks which abound in the neighborhood of Rome. Of the three chief varieties of volcanic rock that exist there, this is the only one which is of little use for purposes of art or trade. It could not have been quarried for profit. It would not have been quarried, therefore, by the Romans, except for the purposes of burial,—and the only inscriptions and other indications of the character of the occupants of these burial-places prove that they were Christian.[1] They are very different from the sepulchres of the great and rich families of Rome, who lined the Appian, the Nomentan, and Flaminian Ways with their tombs, even now magnificent in ruin; very different, too, from the columbaria, or pigeon-holes, in which the ashes of the less wealthy were packed away; and still more different from the sad undistinguished ditch that received the bodies of the poor:—
“Hoc miseræ plebi stabat commune sepulcrum.”
It not unfrequently happens in the soil of the Campagna, that the vein of harder rock in which the catacombs are quarried assumes the soft and sandy character which belongs to it in a state of decomposition. The ancient Romans dug this sand as the modern Romans do; and it seems probable, from the fact that some of the catacombs open out into arenaria, or sandpits, as in the case of the famous one of St. Agnes, that the Christians, in time of persecution, when obliged to bury with secresy, may Lave chosen a locality near some disused sandpit, or near a sandpit belonging to one of their own number, for the easier concealment of their work, and for the safer removal of the quarried tufa. In such cases the tufa may have been broken down into the condition of sand for removal. In later times, as the catacombs were extended, the tufa dug out from one passage was carried into the old passages no longer used; and thus, as the catacomb extended in one direction, it was closed up in another, and the ancient graves were concealed. This is now one of the great impediments in the way of modern exploration; and the same process is being repeated at present; for the Church allows none of the earth or stone to be removed that has been hallowed as the resting-place of the martyrs, and thus, as one passage is now opened, another has to be closed. The archæologists may rebel, but the priests have their way. The ancient filling up was, however, productive of one good result; it preserved some of the graves from the rifling to which most were exposed during the period of the desertion of the catacombs. Most of the graves which are now found with their tiled or marble front complete,
- ↑ The volcanic rocks Are the Tufa litoide, very hard, and used for paving and other such purposes; difficult to be quarried, and unfit for graves on account of this difficulty. The Tufa granulare, a soft, friable, course-grained rock, easily cut,—fitted for excavation. It is in this that the catacombs are made. It is used for very few purposes in Rome. One may now and then see some coarse filling-up of walls done with it, or its square-cut blocks piled up as a fence. The third is the Pura pozzolana,—which is the Tufa granulare in a state of compact sand, yielding to the print of the heel, dug like sand, and used extensively in the unsurpassed mortar of the Roman buildings
