Ralph produced the matches and a cheerful red glow soon radiated upon the stone walls and roof. A sickly, musty smell, the trace of the bats, was still in the air, however, as a reminder of their passing.
The passage soon ended, and the professor’s feet encountered a steep flight of steps cut in the stone, or so it seemed.
“Be careful, boys,” he warned, “a slip here might prove fatal.”
Very cautiously, therefore, they descended into what at first appeared to be a bottomless pit. Suddenly their torches glittered on something that shone like molten metal beneath them.
“A lake,” added Jack, raising his torch so that the light illumined what appeared to be a considerable body of water.
“Water, sure enough,” echoed Pete, “maybe it’s another subterranean river like that one at the Haunted Mesa.”
“This is no river,” said the professor. “See, its surface is as smooth as glass.”
By this time they had descended to the rocky shelf which ran all around the edge of the subterranean lake, while above their torch-light fell redly on a domed roof of dark stone.
“Look! Look!” cried Walter suddenly, “Fish!”
Sure enough, they could now see shoals of white-tinted fish swimming near the surface.
“Can it be that the light attracts them?” wondered Jack.
“Not likely,” said the professor, “I guess they are blind. It is not unusual to find fish in these subterranean lakes. Specimens have been found in our own country and in many places in Europe which boast similar bodies of water.”
Walt had been leaning over the edge of the lake intent, apparently, on trying to catch one of the blind fish. Suddenly he gave a sharp outcry, which was immediately followed by a splash.
“He is overboard!” cried Pete, rushing to the spot and throwing himself on his stomach so as to catch Walt when he rose to the surface. But at that instant a startling thing happened.
Simultaneously almost with the splash of the unlucky ranch boy, there came a sound as of some great body rushing through the water from some remote corner of the cave to which their light did not penetrate. The next instant a cry of real horror broke from all their throats as a terrible misshapen head with blind eyes reared itself above the water and darted at Walt as he rose to the surface.