The tree being now perilously near the edge of the cliff Kris Kringle called a halt.  Next he fastened a rope around the top and another around the base, taking a turn around a rock with each.  One boy was placed on each rope, the others at the pike poles, while the guide stood at the edge giving directions.

The tree trunk gently slipped over under his guidance and a few minutes later rested on the projecting rocks, that were just high enough to hold it in place.

“Wouldn’t take much to send it over, but I guess it will be perfectly safe,” he mused.

“May we go down now?” cried the boys.

“No; I’ll make some steps first.”

He did so with the axe, chopping out scoop-shaped places for steps, until finally he had reached the rock in front of the cave dwellings.

The tree lay at an easy slope, its bushy top partly resting on the ledge, the latter being some eight feet deep by ten feet wide.

Running up the log Mr. Kringle made another rope fast at the top, throwing the free end over.

“Hold on to the rope while you are going down and you’ll be in no danger of falling,” he warned.

The boys scrambled down the tree like so many squirrels, the Professor following somewhat more cautiously.

The explorers found themselves not more than twenty feet from the ground.

“Not much of a door yard.  Where’s the garden?” wondered Stacy, looking about him curiously.

The entrance to the cave dwelling was blocked by a huge boulder, that completely filled the opening.  How it had been gotten there none could say.  The only possible explanation was that the boulder had been found on the shelf and applied to the purpose of protecting the cave dwellers’ home.

“Now we’re here, we can’t get in,” grumbled Ned.

“Nothing is impossible,” answered Kris Kringle.

“Except one thing.”

“What’s that, Master Ned?”

“To hammer the least little bit of sense into the head of my friend, Chunky Brown.”

“You don’t have to, that’s why,” retorted Stacy quickly.  “It has all the sense it’ll hold, now.”

“I guess that will be about all for you, Ned,” laughed Walter.  “At least, Chunky didn’t foul the dinner table when he jumped it.”

The guide, in the meantime, was experimenting with the boulder, inserting a pike pole here and there in an effort to move the big stone.  It remained in place as solidly as if it had grown there.

“There’s some trick about the thing, I know, but what it is gets me.  Better stand back, all of you, in case it comes out all of a sudden,” Mr. Kringle warned them.

All at once the boulder did come out, and it kept on coming.

“Look out!” bellowed the guide.

“Low bridge!” howled Stacy, hopping to one side and crouching against the rocks.

The guide had sprung nimbly to one side as well.  The big rock had popped out like a pea from a pod.  Instead of stopping, however, it continued to roll on toward the edge.