While I was making these measurements, the Indians kept up a low conversation around the hole. A mystery hung around it, transmitted to them by their fathers, and connected with an indefinable sense of apprehension. This mystery might have been solved at any time in five minutes, but none of them had ever thought of doing it, and the old man begged me to come out, saying that if I died they would have to answer for it. Their simplicity and credulity seem hardly credible. They had all sense enough to take their hands out of the fire without being told, but probably to this day they believe that in that hole is the owner of the building. When I came out they looked at me with admiration. They told me that there were other places of the same kind, but they would not show them to me, lest some accident should happen; and as my attempt drew them all from work, and I could not promise myself any satisfactory result, I refrained from insisting. This chamber was formed in the roof of the lower building. That building contained two corridors, and we had always supposed that the great interval between the arches of the parallel corridors was a solid mass of masonry. The discovery of this chamber brought to light a new feature in the construction of these buildings. Whether the other roofs, or any of them, contained chambers, it is impossible to say. Not suspecting anything of the kind, we had made no search for them, and they may exist, but with the holes covered up and hidden by the growth and decay of vegetation. Heretofore I had inclined to the opinion that the subterraneous chambers I had met with were intended for cisterns or reservoirs of water. The position of this in the roof of a building seemed adverse to such an idea, as, in case of a breach, the water might find its way into the apartment below. At the foot of the terrace was a tree, hiding part of the building. Though holding trees in some degree of reverence, around these ruined cities it was a great satisfaction to hear them fall. This one was a noble ramon, which I had ordered to be cut down, and being engaged in another direction, I returned, and found that the Indians had not done so, and they said it was so hard that it would break their axes. These little axes seemed hardly capable of making any impression upon the trunk, and I gave them directions, perhaps still more barbarous to cut away the branches and leave the trunk. They hesitated, and one of them said, in a deprecating tone, that this tree served as food for horses and cattle, and their mistress had always charged them not to cut down such. The poor fellow seemed perplexed between the standing orders of the rancho and the special instructions to do what I required.