We were bruised and bleeding when we reached the foot of the black cliffs whose perpendicular walls towered above us.  We were almost certain that the light had been flashed from a point immediately above the spot where we came face to face with the barrier, but the scaling of the black barricade was a proposition that seemed incapable of solution as we rushed along the base.

“This is the spot,” gasped Holman.  “This big tree cluster was just to the right of the place where the light was flashed.”

“That’s so,” I remarked, “but how are we to get up to the point where the signal came from?”

We raced madly up and down the front of the strange black wall, hunting eagerly for a place that offered the slightest foothold by which we could climb to the terraces that we could see far above, but the search was a futile one.  The tremendous mountain of ebony rock appeared to have been driven up out of the earth during some volcanic disturbance, and as we stumbled blindly along we thought it would be easier to scale the outside wall of a New York skyscraper than the slippery sides of the obstruction in our path.

It was Holman who found a key to the situation.  The big clump of maupei, or Pacific chestnut, that we had taken as a landmark when we were running through the moonlit night, grew close to the barrier, and the limbs of several of the trees scraped the sides of the basalt columns as the faint night breeze moved them backward and forward.

“There’s a ledge up there,” whispered the youngster.  “Look!  It’s about fifty feet from the ground.  If we could climb a tree we might be able to reach it from one of the limbs.”

He had hardly outlined the proposition before we were swarming up the trunk, Holman in the lead by right of discovery, and the nimble Kaipi in the rear.  Higher and higher the youngster climbed into the thick green foliage.  He reached the topmost branches, and selecting one that led toward the rocky wall, he straddled it and worked his way slowly forward.

Kaipi and I clung to the fork of the limb and waited, and as I watched Holman the wisdom of our actions was assailed by a cold doubt.  We had left the two girls entirely unprotected, and if Leith reached the camp before we returned, and heard from the chattering Professor the story of the finding of the scrap of paper, it would be reasonable to suppose that he would consider the moment had arrived for the perpetration of any deviltry he had planned.

But Holman’s actions interrupted my mental criticism of the wisdom of our plans.  The youngster had reached the extreme end of the limb, and he was clawing madly at the rock to obtain a footing.  He succeeded after a five minutes’ struggle, and he sent a breathless whisper back to our perch.

“There’s a ledge here,” he murmured.  “I think we can climb up from it.  Hurry along, and I’ll give you a hand.”

I needed a hand when I reached the end of that leafy seesaw.  I was much heavier than the boy, and the limb could hardly support my weight when I neared the end.  Holman reached out his hand at a moment when I thought that a drop through the air would be my reward for attempting aerial exhibitions, and the next moment I was beside him on a little projection that barely gave us a footing.