"You mean that sort of trampling sound?"
"Yes."
"I thought that was the cattle," put in Merritt.
"No. I hear what Rob means," whispered Harry. "It's riders, and they're coming this way."
The slight sound that had first attracted Rob's keen ears now grew in volume till it resolved itself into the rattle of ponies' hoofs approaching at a smart gallop.
"Here they come!" exclaimed Rob, half unconsciously clasping his rifle.
"Well, they don't seem to be anxious to disguise their approach," commented Harry.
"No, why should they? They figure that only three or four punchers at most are guarding the herd. With the force they have with them they suppose, I guess, that they can scare the punchers off."
"I reckon that's it," agreed Merritt.
Closer and closer drew the galloping, and Merritt began to shift uneasily. The others, too, began to stir about, eager for the word to advance and mount their ponies, which were concealed behind a high rampart of chaparral a few paces off. At last Rob gave the word.