For nearly a hundred yards they progressed with tolerable ease. Then the gorge contracted to such an extent that Peter's broad shoulders were rubbing against either wall. Once or twice he had to turn sideways and drag his pack after him.
"Hope it isn't going to be a blind alley!" he exclaimed.
"Never fear," declared Uncle Brian encouragingly. "The floor is on the down-grade all the time. That's a sure indication that——"
"We're done this trip!" interrupted his nephew. "There's been a fall of rock."
In the subdued light the defile appeared to terminate abruptly in a barrier of enormous stones, some of which must have weighed at least a thousand tons, rising to quite seventy feet.
"Fallen recently," commented Peter. "By Jove! If there's another smash-up, we'll either be flattened out, or trapped. Let's go back!"
Uncle Brian deliberately unburdened himself of his load.
"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."