Six or seven miles farther, and the river widened considerably; before us opened an expanse of water to the farther horizon, and then we sailed out upon an inland sea so large that only a shore-line upon our side was visible to us. The waters all about us were alive with life. There were still a few reptiles; but there were fish by the thousands, by the millions. The water of the inland sea was very warm, almost hot, and the atmosphere was hot and heavy above it. It seemed strange that beyond the buttressed walls of Caprona icebergs floated and the south wind was biting, for only a gentle breeze moved across the face of these living waters, and that was damp and warm. Gradually, we commenced to divest ourselves of our clothing, retaining only sufficient for modesty; but the sun was not hot. It was more the heat of a steam-room than of an oven. We coasted up the shore of the lake in a north-westerly direction, sounding all the time. We found the lake deep and the bottom rocky and steeply shelving toward the center, and once when I moved straight out from shore to take other soundings we could find no bottom whatsoever. In open spaces along the shore we caught occasional glimpses of the distant cliffs, and here they appeared only a trifle less precipitous than those which bound Caprona on the seaward side. My theory is that in a far distant era Caprona was a mighty mountain—perhaps the world’s mightiest mountain—and that in some titanic eruption volcanic action blew off the entire crest, blew thousands of feet of the mountain upward and outward and onto the surrounding continent, leaving a great crater; and then, possibly, the continent sank as ancient continents have been known to do, leaving only the summit of Caprona above the sea. The encircling walls, the central lake, the hot springs which feed the lake, all point to such a conclusion, and the fauna and the flora bear indisputable evidence that Caprona was once part of some great land-mass. As we cruised up along the coast, the landscape continued a more or less open forest, with here and there a small plain where we saw animals grazing. With my glass I could make out a species of large red deer, some antelope and what appeared to be a species of horse; and once I saw the shaggy form of what might have been a monstrous bison. Here was game a plenty! There seemed little danger of starving upon Caprona. The game, however, seemed wary; for the instant the animals discovered us, they threw up their heads and tails and went cavorting off, those farther inland following the example of the others until all were lost in the mazes of the distant forest. Only the great, shaggy ox stood his ground. With lowered head he watched us until we had passed, and then continued feeding.