It was rotten, yet it had corners as hard and sharp as pikes.  It was rough, yet as slippery as ice.  If there was a foot of level surface, that space would be one to break through under a horse’s hoofs.  It was seamed, lined, cracked, ridged, knotted iron.  This lava bed resembled a tremendously magnified clinker.  It had been a running sea of molten flint, boiling, bubbling, spouting, and it had burst its surface into a million sharp facets as it hardened.  The color was dull, dark, angry red, like no other red, inflaming to the eye.  The millions of minute crevices were dominated by deep fissures and holes, ragged and rough beyond all comparison.

The fugitives made slow progress.  They picked a cautious, winding way to and fro in little steps here and there along the many twists of the trail, up and down the unavoidable depressions, round and round the holes.  At noon, so winding back upon itself had been their course, they appeared to have come only a short distance up the lava slope.

It was rough work for them; it was terrible work for the horses.  Blanco Diablo refused to answer to the power of the Yaqui.  He balked, he plunged, he bit and kicked.  He had to be pulled and beaten over many places.  Mercedes’s horse almost threw her, and she was put upon Blanco Sol.  The white charger snorted a protest, then, obedient to Gale’s stern call, patiently lowered his noble head and pawed the lava for a footing that would hold.

The lava caused Gale toil and worry and pain, but he hated the choyas.  As the travel progressed this species of cactus increased in number of plants and in size.  Everywhere the red lava was spotted with little round patches of glistening frosty white.  And under every bunch of choya, along and in the trail, were the discarded joints, like little frosty pine cones covered with spines.  It was utterly impossible always to be on the lookout for these, and when Gale stepped on one, often as not the steel-like thorns pierced leather and flesh.  Gale came almost to believe what he had heard claimed by desert travelers—­that the choya was alive and leaped at man or beast.  Certain it was when Gale passed one, if he did not put all attention to avoiding it, he was hooked through his chaps and held by barbed thorns.  The pain was almost unendurable.  It was like no other.  It burned, stung, beat—­almost seemed to freeze.  It made useless arm or leg.  It made him bite his tongue to keep from crying out.  It made the sweat roll off him.  It made him sick.

Moreover, bad as the choya was for man, it was infinitely worse for beast.  A jagged stab from this poisoned cactus was the only thing Blanco Sol could not stand.  Many times that day, before he carried Mercedes, he had wildly snorted, and then stood trembling while Gale picked broken thorns from the muscular legs.  But after Mercedes had been put upon Sol Gale made sure no choya touched him.

The afternoon passed like the morning, in ceaseless winding and twisting and climbing along this abandoned trail.  Gale saw many waterholes, mostly dry, some containing water, all of them catch-basins, full only after rainy season.  Little ugly bunched bushes, that Gale scarcely recognized as mesquites, grew near these holes; also stunted greasewood and prickly pear.  There was no grass, and the choya alone flourished in that hard soil.