“When I slipped and sank,” he said to himself, “I pulled down that lever, and I opened the water-gate and let out the lake.”

The captain was a man whose mind was perfectly capable of appreciating novel and strange impressions, but with him such impressions always connected themselves, in one way or another, with action:  he could not stand and wonder at the wonderful which had happened—­it always suggested something he must do.  What he now wanted to do was to climb up to the great aperture which lighted the cavern, and see what was outside.  He could not understand how the lake could have gone from its basin without the sound of the rushing waters being heard by any one of the party.

With some difficulty, he climbed up to the cleft and got outside.  Here he had a much better view of the topography of the place than he had yet been able to obtain.  So far as he had explored, his view toward the interior of the country had been impeded by rocks and hills.  Here he had a clear view from the mountains to the sea, and the ridge which he had before seen to the southward he could now examine to greater advantage.  It was this long chain of rocks which had concealed them from their enemies, and on the other side of which must be the ravine in which the Rackbirds had made their camp.

Immediately below the captain was a little gorge, not very deep nor wide, and from its general trend toward the east and south the captain was sure that it formed the upper part of the ravine of the Rackbirds.  At the bottom of it there trickled a little stream.  To the northeast ran another line of low rock, which lost itself in the distance before it blended into the mountains, and at the foot of this must run the stream which had fed the lake.

In their search for water, game, or fellow-beings, no one had climbed these desolate rocks, apparently dry and barren.  But still the captain was puzzled as to the way the water had gone out of the lake.  He did not believe that it had flowed through the ravine below.  There were no signs that there had been a flood down there.  Little vines and plants were growing in chinks of the rocks close to the water.  And, moreover, had a vast deluge rushed out almost beneath the opening which lighted the cave, it must have been heard by some of the party.  He concluded, therefore, that the water had escaped through a subterranean channel below the rocks from which he looked down.

He climbed down the sides of the gorge, and walked along its bottom for two or three hundred yards, until around a jutting point of rock he saw that the sides of the defile separated for a considerable distance, and then, coming together again below, formed a sort of amphitheatre.  The bottom of this was a considerable distance below him, and he did not descend into it, but he saw plainly that it had recently contained water, for pools and puddles were to be seen everywhere.