Quickly the galloping hoofbeats came to a pause. With a motion of his foot, as he sat up amid his blanket and tarpaulin, Bud kicked into the fire a stick of greasewood which flared up, revealing a rider on a panting horse standing over the boy ranchers, all three of whom were now awake.

"Four Eyes!" cried Bud, for the flaring fire had revealed that cowboy. He had accepted his nickname in perfect grace.

"That's who," was the good-natured answer. "I saw the fire as I was riding back, and I thought you'd be here."

"Where were you riding _to_?" asked Bud, pointedly, his fingers releasing their grip on the .45 under the blanket. "I thought you were with Old Billee."

"I was supposed to be," answered Four Eyes, "until my horse got out of the corral and Billee said I could trail him. That's what I was doing when I saw you behind the fire. I knew it was almost burned out, so I didn't stop, or come back to explain."

"Yes, the fire didn't amount to much, though how it was started is another question," said Bud. "You say your black horse got out?"

"Yes, jumped the corral fence. He's a bad one at that."

"You didn't get him back," observed Nort, for he and d.i.c.k, as well as Bud, had noticed that the new cow puncher bestrode one of the extra ponies kept at the camp corral for use in relieving the regular animals.

"No, he got clean away," and Henry Mellon did not seem to worry much about it. "All I have to say," he went on, "is that some one will get a mighty good mount, outside of his habit of jumping out of corrals."

"You may get him back--if whoever picks him up knows where he belongs," said Bud. For in that cow country it was still regarded as a great crime to steal a horse, or keep one known to belong to some one else.

"Oh, I'll prospect a bit farther for him tomorrow, maybe," said Four Eyes. "I didn't want to ride too far this evening, so I turned back. Did you get on any trail of the rustlers?" he asked, for he had been aware of the object of the boys' ride.

"We switched off to come over to the fire," said Bud. "Did you notice anything about it?"

"It was burning pretty good when I struck here, from over at your camp," was the answer. "I saw that it wasn't likely to do much damage, so I didn't ride back to tell Billee and the others."

"Did you see any one suspicious?" Bud went on, getting up and putting more wood on the fire.

"No, I didn't," answered Four Eyes, quietly. "Of course anyone would have had time to start the fire, and get well away before I arrived on the scene--judging by the way it was burning," he said. "Though I can't see what object anyone could have, and I'm inclined to think a pa.s.sing cow puncher--not one of your crowd but some one else--may have flipped a cigarette b.u.t.t into the gra.s.s where it smouldered for some time."

"That may have happened," Bud admitted. "As for an object, if the fire had stampeded the cattle it would have given some bunch of Greasers or rustlers a chance to get away with a few steers."

"Oh, yes, of course," agreed Four Eyes. "Well, I didn't see anybody. Guess I may as well turn in here. No use riding back to the camp to-night. It'll soon be morning."

"That's right, turn in," invited Bud. His suspicions had vanished.

"There's some cold coffee if you want it," added Nort.

"Guess I'll put it on to heat," said Henry Mellon. "It's a bit chilly."

"What time is it?" asked d.i.c.k, as the cowboy stirred up the embers and set the blackened coffee pot on over some stones that had been made into a rude fireplace.

"Two o'clock," announced Four Eyes, with a glance at his watch.

The boy ranchers watched him idly as he made and drank the coffee, munching some hard crackers he carried in one of his pockets. Then, rolling up in their blankets, the quartette went to sleep.

Morning came, in due course, without any untoward incidents having occurred. The boys looked across the fire-swept area to where, beyond it, many cattle could be observed grazing. There was no further vestige of fire. The heavy dew had extinguished the last, smouldering spark.

"Well, I'm going back to the camp," announced Four Byes, as they got the simple breakfast. And how appetizing was that aroma of sizzling bacon and strong coffee! "Want me to tell 'em anything for you!" he asked Bud.

"Tell 'em about the fire," was the request. "And say we're going on the trail of the rustlers. We'll be back to-day, though, around night, for we haven't grub enough to carry us farther."

"What you going to do about your horse?" asked d.i.c.k.

"What can I do?" asked Henry Mellon, in turn. "I can't spend all my time hunting him, when I've got to ride herd."

"We'll be on the lookout," Nort said.

"Hope you have luck," commented the strange cowboy, as he took off his gla.s.ses and wiped them on his silk neckerchief. "I'm lost without Cinder, though this pony isn't so bad," and he patted the neck of the animal he was riding.

A little later the boy ranchers were taking a short cut across the fire-blackened strip, to get on the trail of the men who had driven off their cattle, while Four Eyes turned the head of his pony toward camp.

"Well, it looks as if this was where the trail ended," announced Bud, several hours later.

"Mighty funny, to come to an end so suddenly," commented d.i.c.k.

The three boys had reached one end of the many small valleys into which the larger vale was divided. They had been following the trail of the cattle that had been driven off--it was plain enough until they reached a rocky and shale-covered defile between two small hills. Then, for some reason or other, all "sign" came to an abrupt end. There were no further marks of hoofs in the earth, and none of the ordinary marks to indicate that cattle and horses had been beyond a certain point.

"It's just as Snake said," observed d.i.c.k. "They must have driven the animals here and then lifted them over the hill in an aeroplane."

"They couldn't!" declared Nort.

"I know they couldn't. But how else do you account for it?" asked his brother.

"They may have driven 'em through the pa.s.s, and then scattered dirt and stones over the trail to hide it," suggested Bud.

"Let's look a little farther then," remarked d.i.c.k.

They did, but without discovering any clues. It was as though the rustlers had driven the cattle to the bottom of a rocky and bush-covered slope, and then as if the side of the hill had suddenly opened, providing a way through.

"Like some old fairy yarn!" declared Bud. "This gets me!"

"If we could only have gotten on the trail of the rascals sooner, Bud, we might have learned the secret," spoke Nort. "We ought to keep better watch!"

"How could we?" asked Bud. "We shoot off on the trail, now, as soon as we hear of anything."

"Yes, but we ought to get on the jump quicker," insisted his cousin. "If we had an airship, for instance!" and he laughed at the impracticability of his remark.

"You can see pretty nearly the whole of the valley from the top of Snake Mountain," spoke d.i.c.k, when he and Bud had joined in the laugh at Nort's airship idea. "If one of us could be up there--"

"We'd have to be there all the while!" interrupted Bud. "There's no telling when the rustlers will come. Talk about being on the watch! It's all right to say so, but how you going to work it?"

d.i.c.k suddenly uttered an exclamation.

"What's the matter?" his brother wanted to know. "See a snake?"

"No, but I've got the idea! A watch tower! Why not build one at our camp--or up on the side of the hill back of the reservoir? We could make it of logs--high enough to give us a good view. It wouldn't be much of a trick to climb up in the watch tower three or four times a day and survey the place. A watch tower is the thing, Bud!"