"Let me get past you," he said. "Before we talk of going back, I'll make a brief examination. H'm, yes! Recent fall, eh? You're wrong, Peter. That mass of rock probably subsided a thousand years ago. The dryness of the atmosphere accounts for the fresh-looking stone." "Possibly," rejoined Peter, "but that isn't of much consequence to us, is it? It doesn't make our job any easier. I might be able to scramble up and lower the rope for you." "No climbing for me, thank you," replied his uncle. "I'm going to crawl under." He pointed to a small cavity, barely two feet in height and triangular in section, between two masses of stone inclined one to the other. "You can't possibly," began Peter. "Can't I?" retorted his uncle. "Wait till we shift some of the sand. It may be ten feet deep, but it has accumulated since this rock fell. The stone is quite smooth.... Just come here a minute and kneel down. I fancied I saw daylight; do you?" Peter looked through the narrow tunnel. Sure enough, at about fifty feet away, he could discern the farther end of the horizontal shaft. "No need to dig," he declared. "Stand by. I'll crawl through and pay out the rope." It was a nerve-racking experience. Notwithstanding Uncle Brian's assurance as to the well-established nature of the barrier, Peter was haunted by the dread that the wall of the tunnel might subside; and when about half-way through, he had grave doubts whether he could wriggle past a particularly narrow section. At any rate, there he was. He could not turn to crawl back. He simply had to go on, or get stuck. With his heart figuratively in his mouth, the perspiration pouring down his face, his hands and knees raw with the friction of the sand, Peter continued his way, turning on his side in order to negotiate a couple of narrow places where the rocks protruded. "Worse than the double bottoms of a battleship, any old time," he soliloquized. "Now, if I butt into a particularly venomous snake at the far end--that will be the limit!" At length Peter emerged from the tunnel, rose to his feet, and drew in a copious draught of fresh air. "Through!" he shouted. "Right-o!" sang out his uncle. "Steady on while I finish with the gear.... Now then, haul away!" Peter began to haul in the line. It was heavy work, for at the other end was attached the baggage belonging to both men, Brian Strong's haversack with its precious contents being secured for safety within the folds of the blankets and sleeping-bag. "Good thing the rope's new," thought Peter, carefully coiling away the line as he hauled it in. "If it did part half-way through there'd be a fine old lash-up!" Presently an increased tension of the rope announced that the load was passing the narrowest part of the tunnel, which was about fifteen feet from the end. Then there was a sudden jam. Something had fouled, and the whole of the gear was wedged tightly, forming a formidable barrier between Peter and his relative.