party must be out of ammunition," suggested Adrian, "or they
would give a better account of themselves."

"Our carbines would not carry that far," explained one of the
guards.

"Our Marlins will," replied Adrian, and as he spoke there were
two simultaneous flashes from two of the car windows and two of
the bandits fell, one shot from his horse and the other with his
horse shot under him.

For a moment the other horsemen hesitated as to the course they
should pursue and then, putting spurs to their horses, they
dashed toward the train, just as the express car, having reached
the end of the track, bumped onto the ties and came to a stop.

"Now!" cried Adrian as the riders drew near, firing as they came,
and four shots rang out.

The volley from so unexpected a quarter took the horsemen
completely by surprise, and they pulled up with a jerk. The
action proved their undoing, for as they stood thus for a moment,
they gave those in the train the opportunity they desired and the
volley that followed turned four more riderless horses upon the
plain.

It was more than flesh and blood could stand, and the seven or
eight remaining horsemen turned and fled, followed by at least
three whistling bullets from as many Marlins.

The fight was over and the bullion had been saved, but what of
Broncho Billie, who had been left at the top of the hill four
miles away?

That was the first question asked by Donald when he greeted
Adrian two minutes later.

"Oh, he's all right," was the laughing reply. "He's just taking a
little walk for his health."

But when Billie failed to put in an appearance an hour later, the
boys mounted their horses and started up the track to meet him,
leading Billie's mount between them.

CHAPTER III.

BILLIE LOSES HIS NERVE.

Broncho Billie was not a rapid walker. In fact, if there was any
one thing in which Billie was not a success, it was walking. He
could ride a horse all day, but when it came to depending upon
his own legs as a means of locomotion, he was a dead failure.

Therefore he walked slowly along, counting the ties as he went.

"They certainly do lay 'em thick," he mused after some minutes.
"Three hundred and one, three hundred and two, three hundred and
three, three hundred and four, three hun----"

He stopped short and looked behind him.

"I sure thought I heard some one," he muttered. "It must have
been a bird."

He turned and started forward.

"Let's see, where wa