ers had provided themselves with similar weapons, although theirs
glittered in blatant newness beside Pete's battered, but well-cleaned
and oiled, "shootin' iron."

While they are pressing onward, with the Hachetas lying like a dim,
blue cloud far behind them, let us tell the reader something about the
quest that brings our party into the midst of this inhospitable place.
As readers of "The Border Boys on the Trail" know, Professor
Wintergreen had accompanied Jack Merrill and Ralph Stetson from
Stonefell College, some weeks before, to spend a vacation on the Agua
Caliente Ranch, belonging to Jack's father. The professor, as well as
being on a vacation, was in a sense on a mission, for he bore with him
the commission of a well-known institute of science in the East to
investigate some of the mesas of this part of the world, and also to
procure relics and trophies of the vanished race that once inhabited
them, and accurate measurements of the strange formations.

Since their arrival at the ranch, some weeks before, events had so
shaped themselves as to render the immediate undertaking of his mission
impossible. The descent of Black Ramon de Barros on the ranch, as we
have related, and the subsequent abduction of the boys to the old
Mission across the border, had so fully occupied their attention, that
all thought of the professor's errand had been lost sight of.

With Black Ramon, thanks to the boys, forever banished from his
cattle-rustling raids, and the subsequent tranquility of routine life,
had come a recollection of the professor's quest. Coyote Pete, a few
days before this story opens, had volunteered to act as guide to the
professor and his party to a mesa seldom visited except by wandering
Indians and occasional cow-punchers. This was the Haunted Mesa, the
location of which was so difficult to reach that previous relic-hunting
expeditions had not included it in their travels.

Mr. Merrill was the more willing to allow the boys to go along, as he
had been suddenly summoned into Chihuahua province, in Mexico, by
reports of trouble at a mine--The Esmeralda--he owned there. Rumors of
an insurrection had reached him--an insurrection which meant great
peril to American interests. He had, therefore, lost no time in
setting out to ascertain the true state of affairs at his mine, which,
while a small one, was still likely to develop in time into an
extremely valuable property.

Leaving the ranch in charge of Bu