An _ambulacrum_ or gallery was first excavated around the sides of the area, and several cross passages, as D, E, F, G, H, I, constructed. The walls are thickly lined with graves, and in places the floor has been lowered to give room for still more _loculi_. At D, C, the fossors finding the wall to crumble, had to strengthen it with masonry, and to desist from lowering the floor of the gallery. Hence 172 the latter is not level, but has, in places, steps which have been worn to an inclined plane. The increasing demand for graves led to the formation of the _cubicula_ A1 to A6, as well as others in the interior of the area. Many of these are decorated with frescoes, and A3 is known as the _Capella dei Sacramenti_, or Chapel of the Sacrament, on account of its so-called liturgical paintings. A4 has a coloured marble floor of symmetrical design, and A6 has a large _sepolcro a mensa_ lined with marble and flanked with marble pilasters. The iron bars which supported the table tomb may still be seen. There are many Greek as well as Latin inscriptions in these galleries, and some of the tiles which close the _loculi_ bear the stamp of the emperors M. Aurelius and Commodus, which fixes the date of this area. Some of the passages are entirely paved with such tiles. Numerous niches for lamps also occur. At F a well was excavated which still contains water. It is furnished with foot-holes, that a man might descend in order to clean it out. This is common in other wells in the Catacombs.