At a word Wolf, with a wag of his tail, splashed into the gravelly stream bed.  Hare followed on foot, leading Silvermane.  There were little beds of pebbles and beaches of sand and short steps down which the water babbled.  The canyon was narrow and tortuous; Hare could not see ahead or below, for the projecting red cliffs, growing higher as he descended, walled out the view.  The blue stream of sky above grew bluer and the light and shade less bright.  For an hour he went down steadily without a check, and the farther down the rougher grew the way.  Bowlders wedged in narrow places made foaming waterfalls.  Silvermane clicked down confidently.

The slender stream of water, swelled by seeping springs and little rills, gained the dignity of a brook; it began to dash merrily and hurriedly downward.  The depth of the falls, the height of cliffs, and the size of the bowlders increased in the descent.  Wolf splashed on unmindful; there was a new spirit in his movements; and when he looked back for his laboring companions there was friendly protest in his eyes.  Silvermane’s mien plainly showed that where a dog could go he could follow.  Silvermane’s blood was heated; the desert was an old story to him; it had only tired him and parched his throat; this canyon of downward steps and falls, with ever-deepening drops, was new to him, and roused his mettle; and from his long training in the wilds he had gained a marvellous sure-footedness.

The canyon narrowed as it deepened; the jutting walls leaned together, shutting out the light; the sky above was now a ribbon of blue, only to be seen when Hare threw back his head and stared straight up.

“It’ll be easier climbing up, Silvermane,” he panted—­“if we ever get the chance.”

The sand and gravel and shale had disappeared; all was bare clean-washed rock.  In many places the brook failed as a trail, for it leaped down in white sheets over mossy cliffs.  Hare faced these walls in despair.  But Wolf led on over the ledges and Silvermane followed, nothing daunted.  At last Hare shrank back from a hole which defied him utterly.  Even Wolf hesitated.  The canyon was barely twenty feet wide; the floor ended in a precipice; the stream leaped out and fell into a dark cleft from which no sound arose.  On the right there was a shelf of rock; it was scarce half a foot broad at the narrowest and then apparently vanished altogether.  Hare stared helplessly up at the slanting shut-in walls.

While he hesitated Wolf pattered out upon the ledge and Silvermane stamped restlessly.  With a desperate fear of losing his beloved horse Hare let go the bridle and stepped upon the ledge.  He walked rapidly, for a slow step meant uncertainty and a false one meant death.  He heard the sharp ring of Silvermane’s shoes, and he listened in agonized suspense for the slip, the snort, the crash that he feared must come.  But it did not come.  Seeing nothing except the narrow ledge, yet feeling the blue abyss beneath him, he bent all his mind to his task, and finally walked out into lighter space upon level rock.  To his infinite relief Silvermane appeared rounding a corner out of the dark passage, and was soon beside him.