From there on to the Garden they rode more at ease in the “Boulder Bed,” where lay large blocks of rock of many shapes and sizes that had rolled from some upper strata.  Small shrubs and plants grew on every hand, many-hued lizards and inquisitive swifts darted across the trail, acting as if they resented the intrusion.

Chunky regarded the lizards with disapproving eyes.  But his thoughts were interrupted by the voice of the guide pointing out the Temple of Isis that looks down six thousand feet into the dark depths of the inner abyss, surrounded by innumerable smaller buttes.  The wonderful colorings of the rocks did not suffer by closer inspection; in fact, the colors appeared to be even brighter than when viewed from the rim a few thousand feet above them.

Indian Garden was a delight.  They wanted to tarry there, but were allowed to do so only long enough to permit horses and riders to refresh themselves with the cold water that trickled down through the canals from the springs far above.

Reaching the end of Angel Plateau they gazed down a sheer descent of twelve hundred feet into the black depths of the inner gorge, where flowed the Colorado with a sullen roar that now was borne plainly to their ears.

“It sounds as I have heard the rapids at Niagara do,” declared Chunky somewhat ambiguously.

“All off!” called the guide.

“What’s off?” demanded Chunky.

“Dismount.”

“Is this as far as we go?” questioned Tad.

“It is as far as we go on the pintos.  We have to climb down the rest of the way, and it’s a climb for your life.”

The boys gazed down the wall to the river gorge.  The prospect did not look very inviting.

“I guess maybe I’d better stay here and mind the ’tangs’,” suggested Stacy, a remark that brought smiles to the faces of the other boys.

“No, you’d be falling off if we left you here,” declared Dad.  “You’ll go along with us.”

Before starting on the final thousand feet of the descent the trappings were removed from the horses, after which the animals were staked down so that they might not in a moment of forgetfulness fall over the wall and be dashed to pieces on the rocks below.

Dad got out his climbing ropes, the boys watching the preparations with keen interest.

“Are you going down, Professor?” asked Tad smilingly.

“Certainly I am going down.  I for one have no intention of remaining to watch the stock,” with a grim glance in Chunky’s direction.  Chunky saw fit to ignore the fling at him.  He was gazing off across the chasm at the Temple of Isis, which at that moment absorbed his full attention.

“Now I guess we are ready,” announced the guide finally.  “I will go first.  In places it will be necessary to cling to the rope.  Don’t let go.  Then, in case you stumble, you won’t get the nasty fall that you otherwise would be likely to get.”