“We ought to name this ravine ‘Yellow Canyon,’ all right, sir!” said Scotty to the Colonel as they dismounted and led their horses down the almost perpendicular slopes. “Look at those buttes--all of yellow clay, and worn as smooth as cakes of soap! See how the trees manage to grow, out of every crack and cranny and all their trunks turn up the cliff faces!” “It’ll get down to solid rock soon enough!” replied the Colonel, quietly. “Clay, sandstone, limestone, tertiary, jurassic, triassic--a man can’t help but become something of a geologist, in this country!” he laughed. “You can read a big story of the earth in the walls of these canyons. But wait till you see the Grand Canyon, though! There you’ll see strata enough to write the whole vast epic of the world’s creation!... Mark!--Up on the cliffs!” He pointed upward to where a huge brown bird was just launching into flight from a dead juniper growing down on the face of the yellow cliffs. “Golden eagle!” cried Scotty. “That’s my first! Wonder what in the nation he’s doing, in this gameless land!” “It’s not gameless, for him--and, besides, there’s young lamb! The Navaho flocks are not far from here. They are within easy flight, for that old marauder!” retorted Colonel Colvin. They had now reached the dry, rocky bed of the ravine. It sloped downward in a vast series of ledges, as different strata of rock were cut through. By mid-afternoon they were in the main canyon itself, and searching eagerly its sheer walls for ruins, calling and yodeling, hoping to come upon Sid in one of them. Up under the cliffs at the tops of steep slopes were these prehistoric pueblos, some of them to be reached by easy climbing, others perched on steep, smooth walls that could only have been scaled by a system of pole ladders. “I think we’d better begin shooting signals for Sid, now, boys,” remarked the Colonel with a tinge of anxiety in his voice. “I’ve had my eye open for signs of him for some time, now, but so far we haven’t found a trace. Scotty, suppose you try the .405? It’s the most powerful rifle we have.” Scotty raised the heavy weapon and fired their old private signal. _Bang! Bang! Bang!--Bang!_ it roared out, and the valley of cliffs reëchoed it solemnly down the length of the canyon. They all listened with pent breaths, but no answering shot came. “Wall, I’ll be derned!” ejaculated Big John. “A man’ll hear that big rifle five mile, in this yere canyon! An’ Sid’s .30’s got a right smart whip to it, too, fer answerin’. Shore is funny as a nigger’s mewl!” “And it’s mighty queer Ruler and the pups haven’t picked up any scent of him, too. Who’s got something of Sid’s on him?” asked the Colonel anxiously. Something that was Sid’s! It was with a sense of foreboding that Scotty searched his pockets, in vain, for some trinket, however slight, of his old chum’s, that might serve the hound’s nose.