The general aspect of the interior was as follows:—The southern part, from the shore to the mountain, was covered with woods; the northern part was arid and sandy. Between the volcano and the eastern coast the party were surprised to see a lake, surrounded by evergreens, whose existence they had not suspected. Viewed from such a height it seemed to be on the same level with the sea, but, on reflection, the engineer explained to his companions that it must be at least 300 feet higher, for the plateau on which it lay was as high as that of the coast. “So, then, it is a fresh water lake?” asked Pencroff. “Yes,” said the engineer, “for it must be fed by the mountain streams.” “I can see a little river flowing into it,” said Herbert, pointing to a narrow brook whose source was evidently in the spurs of the western cliff. “True,” said Smith, “and since this brook flows into the lake, there is probably some outlet towards the sea for the overflow. We will see about that when we go back.” This little winding stream and the river so familiar to them were all the watercourses they could see. Nevertheless, it was possible that under those-masses of trees which covered two-thirds of the island, other streams flowed towards the sea. This seemed the more probable from the fertility of the country and its magnificent display of the flora of the temperate zone. In the northern section there was no indication of running water; perhaps there might be stagnant pools in the swampy part of the northeast, but that was all; in the main this region was composed of arid sand-hills and downs, contrasting strongly with the fertility of the larger portion. The volcano did not occupy the centre of the island. It rose in the northwest, and seemed to indicate the dividing line of the two zones. On the southwest, south, and southeast, the beginnings of the spurs were lost in masses of verdure. To the north, on the contrary, these ramifications were plainly visible, subsiding gradually to the level of the sandy plain. On this side, too, when the volcano was active, the eruptions had taken place, and a great bed of lava extended as far as the narrow jaw which formed the northeastern gulf. They remained for an hour at the summit of the mountain. The island lay stretched before them like a plan in relief, with its different tints, green for the forests, yellow for the sands, blue for the water. They understood the configuration of the entire island; only the bottoms of the shady valleys and the depths of the narrow gorges between the spurs of the volcano, concealed by the spreading foliage, escaped their searching eye.