That a far more advanced race had at one time a settlement on the north-west coast is indicated by the cave-paintings and sculptures discovered by Sir George Grey.
Subsequent popes manifested equal ardour, with the same damaging results, in the repair and adornment of the catacombs, and many of the paintings covering their walls, which have been assigned to the period of their original construction, are really the work of these later times.
Both the roof and the walls are almost universally coated with stucco and covered with fresco paintings - in the earlier works merely decorative, in the later always symbolical or historical.
These paintings, it will be seen, are simply decorative, of the same style as the wall-paintings of the baths, and those of Pompeii.
Cemetery interment became a regular trade in the hands of the fossores, or grave-diggers, who appear to have established a kind of property in the catacombs, and whose greed of gain led to that destruction of the religious paintings with which the walls were decorated, for the quarrying of fresh loculi, to which we have already alluded.