were imprisoned underground by a mine explosion; escaping from which,
they met with perils every bit as grave, and from which they were
eventually rescued by Stacy himself.

Through the disaster, the lads solved the Secret of the Ruby Mountain,
thus putting an end for good to the wholesale thieving in the Ozark
range.

Though the Pony Rider Boys had suffered many hardships in their
journeyings, those that lay before them were destined to try them even
more. In "THE PONY RIDER BOYS IN THE ALKALI," they faced the perils of
the baking alkali desert. It will be recalled how they fought
desperately for water when all the usual sources of supply were found
to have run dry; how Tad and Stacy Brown were captured by a desert
hermit and thrown into a cave; how, after their escape, they were lost
in the Desert Maze, and how after many hardships, they finally
succeeded in making their way to camp, dragging behind them a wild
coyote that Tad had roped when the boys were beset by the wild beasts
in the dead of night.

Nothing daunted by their trying experiences the Pony Rider Boys set
out on the concluding trip of the season-- a journey over the historic
plains and mountains of New Mexico. After a long railroad ride, they
had finally arrived at the town of Bluewater, from which they were to
begin their explorations in the southwest.

A guide was to meet and conduct them across the mountains of the Zuni
range and so on to the southern borders of the state.

By the time they reached the platform of the station, the stock car