They called out the Gaynes brothers and broke the news.  For once the jovial youngsters had no joke to make.

“This is getting serious,” said Jimmy, seriously.  “We can’t afford to lose that much.”

George whistled dolefully, and went into the corral for the mules.

The party toiled up the mountain.  Plainly in the dust could be made out the trail of the express ascending and descending.  Plain also were the signs where the driver had dumped out the gold bags and turned around.  From that point the tracks of a man and a horse led to the sheet of rock.  Beyond that, nothing.

The men stared at each other a little frightened.  Somebody swore softly.

“Boys,” said Bright in a strained voice, “do you know how much was in that express?  A half million!  There’s nary earthly hoss can carry over half a ton!  And this one treads as light as a saddler.”

They looked at each other blankly.  Several even glanced in apprehension at the sky.

In a perfunctory manner, for the sake of doing something, those skilled in trail-reading went back over the ground.  Nothing was added to the first experience.  At the point of robbery magically had appeared a man and—­if the stage driver’s solemn assertion that at the time of the hold-up no animal was in sight could be believed—­subsequently, when needed, a large horse.  Whence had they come?  Not along the road in either direction:  the unbroken, deep dust assured that.  Not down the mountain from above, for the cliff rose sheer for at least three hundred feet.  Jimmy Gaynes, following unconsciously the general train of conjecture, craned his neck over the edge of the road.  The broken jagged rock and shale dropped off an hundred feet to a tangle of manzanita and snowbrush.

California John looked over, too.

“Couldn’t even get sheep up that,” said he, “let alone a sixteen-hand horse.”

Old Man Bright was sunk in a superstitious torpor.  He had lost hundreds of thousands where he would have hated to spend pennies; yet the financial part of the loss hardly touched him.  He mumbled fearfully to himself, and took not the slightest interest in the half-hearted attempts to read the mystery.  When the others moved, he moved with them, because he was afraid to be left alone.

After the men had assured themselves again and again that the horse and the man had apparently materialized from thin air exactly at the point of robbery, they again followed the tracks to the broad sheet of rock.  Whither had the robber gone?  Back into the thin air whence he had come.  There was no other solution.  No tracks ahead; an absolute and physical impossibility of anything without wings getting up or down the flanking precipices—­these were the incontestable facts.