They were, as I have said, in the midst of a rolling country, where swales or valleys were interspersed with hills. One moment they had held in view the small bunch of steers that had wandered away from the main herd, but, in another instant, there was no sign of them.
"Listen, and see if you can hear anything," suggested Nort.
Quietly the boy ranchers sat on their horses; the only sounds being the creaking of the damp saddle and stirrup leathers as the animals moved slightly. But there was no sound of lowing cows or snorting steers, and there came to the ears of Nort and Dick no distant shouts of Bud and the cowboys, though the main herd, with the men in charge, could not have been more than two miles away. But, for all that, our heroes were as completely isolated as though a hundred miles distant from civilization.
"I can't understand it!" murmured Dick.
"Nor I," said Nort, "It's just as if those cattle had dropped out of sight in a hole in the ground. Maybe they did, Dick."
"What do you mean?" asked his brother.
"I mean maybe those mysterious professors have been digging big mining holes around here, and that bunch of steers we were chasing just naturally slipped into one. We'd better look out, or we'll drop out of sight ourselves!"
Though he spoke half jokingly, there was some seriousness in Nort's voice, and Dick realized it.
"Those professors sure are queer, with their digging operations," Dick agreed. "I'd like to know what they are after, and why they're hanging around Diamond X."
"Well, I'd like to know that, too," said Nort, "but first of all I'd like to know our way out of this place. There must be some way out, as we didn't have any trouble finding a way in."