“And have they anything to do with the disappearance of the professor?” went on Ned.
“You’ve got me there,” Jerry had to confess. “You see we don’t know whether the marks were made before or after he left us.”
“They can’t have been made very long though,” declared Ned, sliding off his pony and getting down to feel the marks. “They’re comparatively fresh.”
“But what in the world made ’em?” asked Bob.
Neither of his chums could answer, and, at Jerry’s suggestion, they decided to follow the queer trail to see whither it led.
“It may have something to do with the disappearance of the professor, though I doubt it,” said Ned.
After following the queer marks for some distance, not knowing whether they were going toward the starting point or in the opposite direction, the boys encountered a difficulty. The marks came to a sudden stop at the edge of a stretch of land that was smooth shale rock. On that, if the object that made the marks had been dragged, no impression would remain.
“Now let’s go back and start over again,” suggested Ned. “The marks either end here—or begin.”
“More likely begin,” responded Jerry. “If they ended here it wouldn’t amount to a hill of beans as far as helping us is concerned. But let’s go back.”
So they followed the trail back to the spot they had first observed the strange lines in the soft earth. And when they reached this place Ned made another discovery.