For the last ten minutes the thunder had been roaring at intervals, drawing nearer and nearer, and now it crashed directly overhead with a mighty sound that shook the earth and sent Scamp bounding out of his path in terror. Then down came the rain. It was as though a million buckets had been emptied upon him; it fell in livid, hissing sheets and walls, taking strange shapes, like pillars and columns that came from a dim nowhere and rushed past him into the gray void behind. He was drenched ere he could have turned in his saddle; his eyes were filled with rain, it ran dripping from his soaking hat brim and coursed down his arms and chest and back. For a moment even Scamp, experienced cow pony that he was, plunged and snorted loudly, until Roy's voice shouted encouragement. Then he raced forward again. But almost at once his gait shortened; the bed of the arroyo was running with water and the softened sand made heavy going. Roy could scarcely distinguish the walls on either side; but he knew that when the storm had broken the path leading up out of the arroyo was about a half mile ahead of him.

As suddenly as it had begun the deluge lessened. The walls, running with mud, were crumbling and falling here and there in miniature landslides. Scamp was plunging badly in the soft ground, and so Roy slowed him down to a trot. He could not, he told himself grimly, get one speck wetter. There was little use in hurrying. With sudden recollection of his bundles, Roy glanced back. Only a wisp of wet brown paper sticking to the cantle remained; the water had soaked the wrappings—baking powder, flavoring extract, dried fruit, and all the rest of it, had utterly disappeared.

But Roy's regrets were cut short by Scamp. That animal suddenly stopped short, pricked his ears forward, and showed every symptom of terror. Roy, wondering, urged him onward. But two steps beyond the horse again stopped and strove to turn. Roy quieted him and, peering forward up the gully, through the driving mist of rain, tried to account for the animal's fright. Was it a bear? he wondered. He knew that there were some in the foothills, and it was quite possible that one had taken shelter here in the arroyo. Then, as he looked, a roaring sound, which the boy had mistaken for the beat of the rain, rose and grew in volume until it drowned the hissing of the storm and filled the arroyo. Around a bend of the gully only a few yards ahead came a wave of turbid, yellow water, bearing above it a great rolling bank of white froth.

For an instant Roy gazed. Then, heart in mouth, he swung Scamp on his haunches and tore madly back the way he had come. He knew on the instant what had happened. There had been a cloud-burst on the mesa or among the foothills, and all the little gullies had emptied their water into the mouth of the arroyo. He knew also that if the flood caught him there between those prisonlike walls he would be drowned like a rat. The nearest place of refuge was a mile and a half away!

After the first moment of wild terror he grew calm. On his courage and coolness rested his chance for life. He crouched far over the saddle horn and lashed Scamp with the dripping quirt. Urging was unnecessary, for it seemed the horse knew that Death was rushing along behind them. He raced as Roy had never seen him run before. The walls rushed by, dim and misty. In a minute Boy gathered courage to glance back over his shoulder. His heart sank—only a yard or two behind them rushed the foam-topped wave. Here and there the sides of the arroyo melted in the flood and toppled downward, yards at a time, sending the yellow water high in air, but making no sound above its roaring. Behind the first wave, perhaps a half hundred feet to the rear, came a second, showing no froth on its crest, but higher and mightier. And farther back the arroyo seemed filled almost to the tops of the banks with the rushing waters. Roy used the quirt ruthlessly, searching the banks as they sped by in the forlorn hope of finding some place that would offer a means of egress, yet knowing well as he did so that the nearest way out was still a full mile distant.

He wondered what death by drowning was like. Somewhere he had read that it was painless and quick; but that was in a story. Then he wondered what his mother would do without him to fetch the water from the cistern back of the kitchen, and feed the chickens and look after the hives. He wondered, too, if they would ever find his body—and Scamp's! The thought that poor, gallant old Scamp must die too struck him as the hardest thing of all. He loved Scamp as he loved none else save father and mother; they had had their little disagreements, when Scamp refused to come to the halter in the corral and had to be roped, but they always made up, with petting and sugar beets from Roy and remorseful whinnies and lipping of the boy's cheek from Scamp. And now Scamp must be drowned!

It was difficult going now, for the turbid stream reached above the horse's knees; but the animal was mad with fright, and he plunged desperately onward. Roy looked up toward the gray skies, through a world of gleaming rain, and said both the prayers he knew. After that he felt better, somehow, and when the second wave caught them, almost bearing Scamp from his sturdy feet, he looked calmly about him, searching the uncertain shadows which he knew were the walls of the chasm. He had made up his mind to give Scamp a chance for life. He tossed aside his quirt, patted the wet neck of the plunging animal and whispered a choking "Good-by." Then, as the flood swept the horse from his feet and swung him sideways against one wall, Roy kicked his feet from the stirrups and sprang blindly toward the bank, clutching in space.

He struck against the soggy earth and, still clutching with his hands, sank downward inch by inch, his crooked fingers bringing the moist clay with them and his feet finding no lodgment. The water swept him outward then, tearing at his writhing legs. Just as his last clutch failed him his other hand encountered something that was not bare, crumbling earth, and held it desperately. The flood buffeted him and tossed the lower half of his body to and fro like a straw. The muddy water splashed into his face, blinding, choking him. But the object within his grasp remained firm. For a moment he swung there, gasping, with closed eyes. Then he blinked the water from his lids and looked. His left hand was clutching the thick tap root of a greasewood. In an instant he seized it with his other hand as well, and looked about him. Scamp was no longer in sight. The water was rising rapidly. The noise was terrific. All about him the walls, undermined by the flood, were slipping down in wet, crumbling masses. He wondered if the root would hold him, and prayed that it might. Then the water came up to his breast, and he knew that if he were to save himself he must manage somehow to crawl upward. Perhaps—perhaps he might even climb quite out of the chasm! If only the earth and the root would hold!

Taking a deep breath he clutched the tap root a foot higher and tried his weight upon it. It held like a rope. He pulled himself a foot higher from the waters. Once more, and then he found that he had command of his legs and could dig his feet into the unstable clay. Then, inch by inch, scarce daring to hope, he pulled himself up, up until he was free of the flood and between him and the ground above only a scant yard remained. Below him the rushing torrents roared, as though angry at his escape, and tossed horrid yellow spray upon him.

Once more he took fresh grip of the slippery root, watching anxiously the low bush at the edge of the bank. Each moment he thought to see it give toward him and send him tossing back into the water. But still it held. At last, hours and hours it seemed since he had first begun his journey, his hand clutched the edge of the bank, but the earth came away in wet handfuls at every clutch. At length his fingers encountered a sprawling root or branch, he knew not which, just beyond his sight; and, digging his toes into the wall in a final despairing effort, he scrambled over the brink and rolled fainting to the rain-soaked ground.