It was so agreed. Hess went out and helped Frank bring in the animals and wood for the cooking fire.
But here was a surprise. Almost as soon as the horses clattered in on the hard floor of the cavern one of them whinnied. Seemingly in response, the reechoing sound that had previously so startled the girls rang faintly through the cavern. But from much farther away, it seemed, than before.
"The haunt!" gasped Bess. "There it is again."
The men and Walter looked inquiringly at each other. Tom Collins shook his head: "Can it be the echo of that little roan of mine squealing?"
"Never!" cried Rhoda. "That doesn't sound like any horse I ever heard. Why, it's queer!"
"Queer's the word; but horse queer," muttered Tom.
Walter looked eagerly at Nan in the lamplight.
"Do you believe that black horse is somewhere here?" she whispered.
"I most certainly do, Nan," he said with confidence.
They worked all the evening on that stone. Occasionally the faint and mysterious sound floated to them. The men would not give their opinion about this, but they were warmly expressive of what they thought about the boulder that had to be moved.