Ancient cities, as we now know--whether at Troy, Lachish, and Gezer, or at Rome and in London--were constantly rebuilt on the ruins of towns previously laid waste or burned. They present successive strata, with buildings that are themselves not all of one date, and which were sometimes carried down to rock, sometimes merely founded on the old walls and roofs. The street pavements and the lintels of city gates were renewed even within the period of one city, and more frequently than the walls and other buildings. The earth was disturbed, so that old objects were brought up to the surface, and recent objects fell into the foundation trenches, presenting many puzzles for the explorer; but, broadly speaking, the strata are as a rule clearly traceable, giving an historic sequence for the successive cities. In parts of Jerusalem the valleys within the walls have gradually been filled with earth and ruined masonry to a depth of 40 or 50 feet, and it is only where the bare rock is on the surface that we can feel we are standing on the very ground trodden by the feet of our Lord. There are at least six successive cities to be studied at Jerusalem, lying one above another where the depth of the debris is greatest. Within quite recent times the level of some streets has been raised when they were repaved. In the twelfth century “Christian Street,” as it is now called, rose gradually northward, being about 15 feet higher up hill at the point where it passed the west door of the Cathedral of the Holy Sepulchre than at the corner where it joined David Street, and where was the Chapel of St. John Baptist belonging to the Knights of St. John. But to-day Christian Street runs level, and the floor of the chapel is 25 feet below the street, being on the same level as that of the floor of the cathedral. Yet even this chapel floor is 10 feet above the original level of the rock, as it descends into the great Tyropœon Valley. When I first visited Jerusalem, the buildings of the Hospital were covered with earth for some depth above the vaulted roofs of the twelfth-century buildings. Soon after, this earth was removed on donkeys, which passed in a long procession daily out at the west gate, where they made a mound on which Jewish shops now stand. Thus the central valley was filled in, to a depth of 20 feet, before the Crusaders began to build, and has been again filled in another 20 feet or more since the thirteenth century; while on the outside of the Temple, as we stand on the pavement at the Jews’ Wailing-place and gaze on the mighty rampart towering above, we must remember that we only see less than half its present height, and that it goes down beneath us nearly 40 feet, to the older pavement of Herod’s age, which was itself 20 feet above the foundation rocks. The causeway to the north of this is 90 feet above the rock, but in the sixth century the street was at least 40 feet lower, and in the time of Herod some 30 feet lower still,