But nothing of the sort followed.  The mustang was as meek as could be.  Stacy rode the animal up and down the field until satisfied that the pinto was thoroughly broken.  Stacy was an object of interest to all.  He was a very much banged-up gentleman, nor was Tad so very far behind him in that respect.

Young Butler chose for his mount a mustang with a white face.  Already Tad had decided to call him Silver Face.  The two very quickly came to an understanding, after a lively but brief rustle about the enclosure.  After this Tad roped out the pintos for the others of his party.  This done, the boys took their mustangs out into the field, where they tried them out.  The spectators were then treated to an exhibition of real riding, though the Pony Riders were not doing this for the sake of showing off.  They wanted to try their mounts out thoroughly before deciding to keep those they had chosen.

At last they decided that the stock could stand as picked out, with the exception of Walter Perkins’s mustang, which went lame shortly after the boy had started off with him.

“I guess we are all right now,” announced Tad, riding up to where the Professor and Jim Nance were standing.  “Has either of you any suggestions to offer?”

“Hain’t got no suggestions to offer to the likes of you,” grumbled the guide.  “Where’d you learn to ride like that?”

“Oh, I don’t know.  It came natural, I guess,” replied Tad simply.  “The others ride as well as I do.”

“Then we’ll be moving.  I reckon you are figgering on gitting started to-day?”

“Yes, we might as well be on our way as soon as you are ready, Mr. Nance,” agreed the Professor.

“How about the pack train?” asked Tad.

“The mules are all ready,” answered the guide.

The lads rode their new horses back to Flagstaff.  None cared to ride in the buckboard long as there was a horse to ride.  Even the Professor thought he would feel at home in the saddle once more.  Nance observed that though Professor Zepplin was not the equal of the Pony Riders on horseback, yet he was a good man in the saddle.  Nance was observing them all.  He knew they would be together for some weeks and it was well to understand the peculiarities of each one of the party at the earliest possible moment.

Reaching town the party found that the entire equipment for the pack train had been gotten in readiness.  There remained but to pack the mules and they would be ready for their start.  This was done with a will, and about two o’clock in the afternoon the outfit set off over the stage road, headed for the Grand Canyon.

It was a happy party, full of song and jest and joy for that which was before them.  The way led through the Coconino Park.  Some three miles out they halted at the edge of a dry lake basin, in the centre of which was a great gaping hole.  The Professor pointed to it inquiringly.