"Now do _you_ understand this?" asked l'Encuerado, addressing Lucien; "I don't." "Yes, I do, a little." "Well, you are very fortunate! The other day stones were said to come from the sun or moon, and fly about all covered with fire; now, they are formed by water. Perhaps M. Sumichrast will tell us to-morrow that they come from the wind." The Indian then walked away, quite indignant; we followed him, smiling at his anger, becoming more and more enchanted by the spectacle which met our eyes. Unfortunately, our torches gave a very insufficient light, and the thick smoke rapidly blackened the arches above us. A great polished stone now impeded our passage, and compelled us to crawl. I took the lead, and, passing through a kind of narrow corridor, made my way into a small chamber. I raised a sudden exclamation; for five or six skulls, symmetrically arranged, seemed to glare at me through their empty orbits. "Oh father!" cried Lucien, "are we in a cemetery?" [Illustration: "Five or six skulls . . . seemed to glare at me through their empty orbits."] "Yes, my boy; I think this must be a Chichimec burial-place. This nation, which preceded the Toltecs and Aztecs in Mexico, were in the habit of depositing their dead in caverns." Sumichrast examined a skull which he had picked up; its white and perfect teeth showed that it must have belonged to a man who died young. A few paces farther on five or six more skulls lay on the surface of the ground; they were inclosed in by fine stalactites, and appeared as if they were grinning at us through the bars of a dungeon.