Above their heads the roof rose, misty and indistinct in the feeble light that pervaded this vast hall. The atmosphere felt cold after the heat outside, so that it chilled them and made them shiver. Lighted only by those narrow windows and slits, which were placed high up the thick walls, a mystic shadow, like the forest gloom, added to the vastness. They seemed within a mammoth cavern. The floor was slabbed with stones, and destitute of furniture, while a thick layer of dust and fine sand deadened the sounds of their footsteps. For a time no one dare utter a word, so profoundly had that gloomy vastness and deathly silence impressed them. At last Ned spoke, and at the hollow sound of his voice they all started; it seemed as if the words had been instantly carried away, to be repeated faintly in the roof. "I wonder what they used this place for? Look at those figures on the walls." The walls, which they could now see more plainly than at first, were covered with strange designs of figures and animals--men, with the heads of birds and beasts; warriors in chariots, on horseback, and on foot; captives being driven along. All the pastimes and pursuits of the builders were here portrayed in colours, in which black, red, yellow, and blue predominated. These were faded with age, yet, with but few exceptions, in perfect condition as far as the outlines were concerned. There were no openings along the entire sides, nor, with the exception of the passage by which they had entered, were there any other portals. But at the far end they could see daylight shining through a number of dislodged slabs, which partly blocked up what appeared to be a much longer passage than that behind them. As they grew accustomed to the faint light they were able to make out two smaller doorways on each side of the centre passage. Ned strode boldly, followed by his comrades, to the aperture nearest him. Inside they found a small chamber; at least, it looked so after the hall. Yet it was twenty feet wide by nearly thirty long. It was lighted from the outer side, and at the end was a small doorway, on entering which they found themselves at the foot of a staircase, which led upwards, as they naturally supposed, to other chambers and to the roof. For the present they deferred the further investigation of this stair, and tried the other door of the hall. A similar apartment waited them here, with a ceiling of the same height, namely, about eighteen feet. But at the end they found themselves confronted by a flight of steps leading downwards. It was wide enough for four men to walk abreast, and in good condition. Also, although darker than the hall, yet it was fairly well lighted by slits in the wall. "Ah, this is the road I want to take!" said Ned. "Come along with your traps, boys."