"Such as what-like?" asked Slim, willing to let Bud take the lead, as the search for the rustlers was distinctly an affair of the boy ranchers.

"We ought not to go ahead, all in a bunch," decided Bud. "We may run into a bunch of Greasers at some turn of the trail, and if we have scouts out we can handle the situation better."

"I was going to suggest it," said Slim, "but I thought you'd think of it yourself, Bud, being as you're your paw's son."

Bud was pleased at the implied compliment, and, a little later, as they advanced, they were divided into three small parties, with rear and vanguard, to insure against a surprise in back, which might easily happen.

And so they advanced through the defile, keeping watch on both sides of the trail. There were still evidences that a herd of cattle had been driven along the rocky defile, but because of the rocky floor, if such it may be called, the signs were faint, and only an experienced westerner could have picked them up. But the boy ranchers were accompanied by experienced cow punchers, who knew every trick of the trail.

Bud had insisted that it was one of his rights to ride in the advance guard, with Yellin' Kid, and it was while they were performing this duty, of watching for a surprise, that they saw, just around the bend of the trail, some wisps of white vapor floating up.

"There they are!" exclaimed Bud in a hoarse whisper, pointing. "They've stopped there—or some of 'em have. Or maybe it's the person who fired the warning shot."

"Might be," admitted Yellin' Kid, toning his voice down somewhat to suit the occasion. "Better let me get off and crawl ahead, Bud. I'm used to that. You hold the horses."

Bud realized the sense of this proposition, and he held the reins of the Kid's horse, while that cow puncher slipped from the saddle, and, on all fours, crept toward the wall of rock which rose abruptly at a turn of the trail shutting off a view beyond.

Bud watched Yellin' Kid closely, the lad's hand on the butt of his .45, and occasionally he glanced back to catch the first glimpse of the main party, so he might warn them. He saw the wisps of vapor rising and floating toward him.