"The Indians!" gasped Rob; "they're after us! Up the steps, everybody, quick!"

A rush for the rough stone steps followed, and so fast did the boys press forward that Rob had to warn them of the danger of speed.

"If you slipped you'd be over the edge," he said.

It was enough. The rush moderated. The thought of slipping off into black s.p.a.ce was enough to alarm the stoutest hearts among them.

Tubby was the last up but Rob, who remained behind with drawn revolver.

He had nerved himself to fire at the first Indian head that showed out of the tunnel.

"Come on, up with you," Rob urged, as the fat boy placed his foot on the rough flight hewn in the sheer face of the cliff.

"All right, Rob," rejoined the stout youth, scrambling upward. "I'll be up before----"

He broke off short, with a terrible cry that rang out far into the night.

Rob, speechless with horror, saw the stout youth's feet slip from under him, and his hands clutch unavailingly at the smooth face of the cliff.

The next instant--for the whole thing happened in the wink of an instantaneous photographic shutter--Tubby was gone.

With a dreadful sinking of his heart, Rob stretched far over the edge of the ledge, which hung like some flying thing, between heaven and earth.

Below him was utter blackness.

CHAPTER XI.

CAPTURED BY MOQUIS.

Too frightened to utter a sound, the others, who by this time had reached the summit of the cliff, gazed over into the inky depths beneath them. It was Merritt who first found his voice.

"Rob, oh, Rob! What has happened?"

"Don't ask me yet," gasped the boy below him, and, throwing himself flat on the narrow shelf, he peered over into the black void.

"Tubby, Tubby!" he called softly.

"Gee, that was a drop, all right!" came up a voice from below him.

The astonished Rob almost fell over the edge of the ledge himself in his excitement.

"Oh, Tubby, is that really you?"

"I guess so," came the voice below, "but I wish you fellows would hurry up and get me out of this; I'm hungry."

"Gracious!" thought Rob; "fancy thinking of hunger in such a position as he is in."

"I'm clinging to a tree," came up Tubby's voice. "I grabbed it as I was falling. It's only a very little tree, though, and I don't just know how long it'll bear me."

"Get in as close to the roots of it as you can," breathed Rob, hardly daring to speak above a whisper for fear of dislodging his chum by the mere vibration of his voice.

"All right," said Tubby, and Rob could hear him cautiously making his way along his slender aerial perch.

Rob turned his face upward and hailed his corporal.

"Say, Merritt," he cried, "take the fellows, and get back to camp as quick as your legs will carry you, and then get back up here again.

Bring ponies and ropes with you--all you can get of them, and maybe Blinky and some of the men had better come."

"All right, Rob. But how about you?"

"I'll wait here. Hurry back, now."

"We will," and an instant later Rob was alone, and his companions were making full speed to the camp.

"How are you making out, Tubby?" called down Rob in a low tone.

"All right. But my legs are cramped. Gee! I was lucky to strike this tree."

"You bet you were. I noticed a few small ones clinging to the rocks as we peeped over, but I didn't think they'd ever be the means of saving a life."

"Don't holler till we're out of the wood. It's bad luck."

"Well, they ought to be back within an hour with the ropes. I guess they can get ponies up that trail."

"I hope so," groaned Tubby. "I don't think I can hold out much longer."

"Good gracious!" gasped Rob, "is the tree beginning to give?"

"No, without grub, I mean. I tried to eat some of the leaves off this tree, but they're bitter and don't taste just right."

"What! You've been moving about?"

"Sure. I've got to have something to do."

The very idea of any one's stretching their limbs in such a position as the fat boy's, almost made Rob's hair stand on end.

"Tubby must have nerves of steel," he murmured, "or else not know the meaning of fear."

Then he went on aloud:

"For goodness' sake, don't move any more, Tubby. The slightest false move might send you off into s.p.a.ce."

"All right, I'll keep still," Tubby a.s.sured him, but in a free-and-easy tone.

"Well, perhaps it's a good thing he isn't scared," thought Rob; "if he were, it would make the job of getting him up twice as difficult."