“Oh, goodness me! I hope this isn’t going to be another experience like that one on the Bad Lands in the Colorado Rockies!” cried Anne, who claimed that she never did get over the effects of all the alkali dust she inhaled that day.

“It may be necessary for us, Anne,” replied Julie, hoping to encourage the girls. “We’ve not eaten our usual peck of sand this year, you know. Now we have to have it all in one swallow.”

Meanwhile every one was busy getting ready to battle with the simoon, or sand-storm, as the Indians call it.

Finally it began to be felt. The wind, which had been increasing in its velocity ever since the guides returned from the lookout crest, now blew the dust-like grains of sand across the desert and soon obliterated all trails and other land-marks. But the horses battled on, urged by their riders to reach the upthrust of mesa which was now but half a mile ahead.

Before the scouts could more than hope to reach the scanty protection of this irregular formation of rock and yellow pumice, the storm was blowing in all its fury. Several times the horses, first one, then another, lost footing and slithered half-over in the drifting sand.

Joan’s horse heretofore had been considered one of the best mounts in the group, but in the test of endurance it failed to measure up to the Indian ponies bought at the Mission, or with the raw-boned animals the other scouts were riding.

Every scout was now fighting a single-handed battle with the hurricane, fighting the stinging, blinding sand while trying to guide the horse after the Indians who led the way. The great billows of dust were caught up in clouds and were kept driving over the waste-lands in such volume as to create a panic in any heart.

Then came the unexpected. From somewhere near by—possibly the whirling gale brought it from the very same rocky haven they were seeking—something as large as an orange struck Joan’s horse on the side of the face. The half-crazed animal failed to respond to his driver, and, in one leap, was away from the rest of the riders.

Down a hilly declivity dug out by the gale went the mad horse, sliding upon its haunches with Joan almost standing upright in the stirrups. Then up a sand-dune, staggering and pulling on the reins till his rider was dizzy with the swaying. Finally the beast reached a gravel-pit whence the covering of sand had just been swept up and the next blanket of sand had not yet been deposited. Momentum sent him sliding down into this yawning pit.

Instantly Joan saw she must force the breathless animal up out of this hollow or they both would be buried alive. Her breath came like blasts from an exhaust pipe, her eyes flamed as with a thousand fiery sparks, the blood pounded in her head with triphammer regularity, still the scout could think, and think she did!