gulch, with slide rock to cut off any approach from the main ridge.
Flying low, they could actually identify fat Sanchez and his two
companions, who had their pack burros with them. It seemed too good to be
true! But before they could decide whether to sail down and try to
capture them themselves, or to go for Long Lester, the oncoming storm
began to set them careening, and they had to fly out of the elements at
right angles to the storm's approach.

Returning three hours later with the old ex-deputy sheriff,--it was a
spot not to be mistaken,--Ace gazed in complete stupefaction at the gulch
where the Mexicans had been encamped. For there was now nothing there but
slide-rock!

The dust that still grayed the atmosphere spoke clearly of the
catastrophe. And there would not have been one chance in a million of
their escaping. That they had not done so, their non-appearance anywhere
in the neighborhood bore abundant testimony.

The Mexicans had been captured by those same natural forces they had
tampered with when they set the forest fires. The little camping party
was free to return as soon as their time was up.

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[Transcriber's Note: Each term described in the glossary originally had
a pronunciation key in parenthesis. This key contained letters that are
not available in any modern font, including UTF-8, and therefore is not
displayable. Images of the original pronunciation keys are provided in
the HTML version. Pronunciation keys are omitted in this text version.]

GLOSSARY

Archeopteryx, a fossil bird that had teeth and whose spinal column
extended into the tail.

Archeozoic, the era in which the simplest forms of life originated.

Basalt, a dark brown or black igneous rock.

Calcite, calcium carbonate, a rock that includes limestone and marble.

Cambrian, the first period of the Paleozoic era,--that of the first
abundance of marine animals.

Carboniferous, producing or containing coal.

Cenozoic, the age of mammal dominance. It included the last great ice
age, the time of the transformation of apes into man, and the rise of
the higher mammals.

Comanchian, that period of the Mesozoic era that gave rise to flowers
and the higher insects.

Cretaceous, that period of the Mesozoic era that gave rise to the
primitive mammals.

Dinosaur, an order of extinct reptiles, of which there were a dozen
varieties, mostly lizardlike and of