appeared to be very large; neither to east nor to west could I see any end to the vista of green-capped cliffs. Below, it is a swampy, jungly region, full of snakes, insects, and fever. It is a natural protection to this singular country."
"Did you see any other trace of life?"
"No, sir, I did not; but during the week that we lay encamped at the base of the cliff we heard some very strange noises from above."
"But the creature that the American drew? How do you account for that?"
"We can only suppose that he must have made his way to the summit and seen it there. We know, therefore, that there is a way up. We know equally that it must be a very difficult one, otherwise the creatures would have come down and overrun the surrounding country. Surely that is clear?"
"But how did they come to be there?"
"I do not think that the problem is a very obscure one," said the Professor; "there can only be one explanation. South America is, as you may have heard, a granite continent. At this single point in the interior there has been, in some far distant age, a great, sudden volcanic upheaval. These cliffs, I may remark, are basaltic, and therefore plutonic. An area, as large perhaps as Sussex, has been lifted up en bloc with all its living contents, and cut off by perpendicular precipices of a hardness which defies erosion from all the rest of the continent. What is the result? Why, the ordinary laws of Nature are
