Again and again, as they went on, places of this kind were met with; while twice over they had to pause at spots where the water must have sprung from a shelf ten or a dozen feet down into a basin which it had hollowed for itself in the course of time.
Upon the first of these sudden drops presenting itself Mike stopped with the lanthorn.
“Here’s the end of it,” he said. “Goes down into a sort of bottomless pit, black as ink. Let’s go back.”
Vince stepped close to his side and gazed down into the black depths with a feeling of awe, the place looking the more terrible from the fact that the tunnel had narrowed until there was only just room for them to stand between the smooth granite walls.
“Looks rather horrid,” said Vince. “Worse than a big well. Let’s see how deep it is.”
He stepped back and picked up a stone that had fallen from the roof, returning to where Mike held up the lanthorn for him to see.
Down went the block of stone, and they prepared themselves to hear it go bounding and echoing far away in the bowels of the earth; but it stopped instantly with a loud clang, and Vince cried,—
“Why, it isn’t deep at all! I can see it.”
A ring or two of the rope was cast loose, passed through the handle of the lanthorn, and upon lowering it down block after block presented itself sufficient to enable them to descend into what proved to be quite a hollow, from which the stream must have leapt into another and again into another, each being a fall of only a few feet. After which there was another great pot-hole, like a vast mortar with a handleless pestle of rock remaining therein.
Beyond this the water had carved out a rugged trough, steep enough to form a slide if they had felt disposed to trust themselves to it, and Vince laughingly suggested that they should glide down.