a moment more he was inside of the cavern and crawling along on hands and knees.

He had not far to go in this fashion. Twenty feet beyond the cavern became so large that he could stand up with ease. He flashed the light above his head.

"By Jove! a miniature Mammoth Cave of Kentucky!" burst from his lips.

On he went until a bend in the formation of the cavern was gained. Here the stream of water disappeared under a pile of loose stones, and the opening became less than six feet in height.

"Checked!" he muttered, and his face fell. It looked as if he would have to go back the way he had come.

Again he raised his light and gazed about him with more care than ever.

The loose rocks soon caught his attention, and, setting down the lantern, he began to pull away first at one and then another.

The last turned back, he saw another opening, evidently leading upward.

"This must lead to the open air—" he began, when a grinding of stone caught his ears. In a twinkle a veritable shower of rocks came down around his head. He was knocked flat and almost covered.

For fully ten minutes he lay gasping for breath. The blood was flowing from a wound on his cheek, and it was a wonder that he had not been killed.

"In the future I'll have more care," he groaned, as, throwing first one stone and then another aside, he sat up. The falling of the stones had been followed by some dirt, and now a regular landslide came after, burying him up to the armpits.

"Planted," was the single word which issued from his lips. He was not seriously hurt, and was half inclined to laugh at his predicament. Still, on the whole, it was no laughing matter, and Pawnee Brown lost no time in trying to dig himself free.

The stones and dirt were wedged tightly about his legs, and not wishing to run the risk of a broken or twisted ankle, the scout worked with care, all the time wondering if Dick Arbuckle was back, and never once dreaming of the peril the poor lad was encountering. The rain was soaking through the ceiling of the cavern, and the situation was far from a comfortable one.

At last he was free again, and striking a match, he hunted up the lantern and lit it once more.

The opening to the inner cave was now large enough to pass through with ease, and making sure of his footing, the scout moved forward, straining his eyes eagerly for some sign of an egress to the outer world.

Presently he saw a number of straggly things dangling downward from the rocks and soil overhead.

They were the bottom roots of some great tree standing fifteen or twenty feet above.

"Not far from the surface now, that's certain," he thought, with considerable satisfaction. "And yet, hang me if I can see an opening of any sort yet."

On and on he went, until nearly a hundred feet more had been passed.

The cave had widened out, but now it narrowed once again to less than a dozen feet. The roof, too, sloped downward until it occasionally scraped the crown of his sombrero.

The light of the lantern began to splutter and flare up, showing that the oil in the cup was running low.

"If only the thing lasts until I find the door to this confounded prison," he thought.

Suddenly a peculiar hiss sounded out upon the darkness.

Pawnee Brown knew that hiss only too well, and leaping back he snatched a pistol from his belt.

The hiss was followed by a rattle, and now, flashing the light around, the scout saw upon a flat rock the curled-up form of a huge rattlesnake.

The eyes of the reptile shone like twin stars, and when Pawnee Brown discovered him he was getting ready to strike.

The rattler was less than six feet away, and the scout knew that he could cover that space with ease. Therefore, whatever was to be done must be done quickly.

Like a flash the pistol came up. But ere Pawnee Brown could fire a curious thing happened.

A large drop of water, splashing down from the roof of the cavern, caused the light to splutter and go out.

The scout was in the dark with his enemy.

More than this, he was boxed up in a narrow place, from which escape was well-nigh impossible.

Aiming as best he could under the circumstances, he fired.

The bullet struck the flat rock, bounded up to the side wall of the cavern and then hit him in the leg.

"Missed, by thunder!"

He jumped past the spot and moved up the cavern a distance of several yards.

A rattle and a whirr followed, as the great rattlesnake made a vicious strike in the dark. An intense hiss sounded out when the reptile realized that the object of his anger had been missed.

Listening with strained ears, the boomer heard the deadly thing sliding slowly from rock to rock, coming closer at every movement.

To flee was impossible, so with bated breath he stood his ground.

CHAPTER IV.

OUT OF THE CAVERN.

Slowly but surely the great rattlesnake came closer to where Pawnee Brown stood motionless in the darkness of the cavern.

The reptile had been enraged by the shot the great scout fired, and now meant to strike, and that fatally.

Listening with ears strained to their utmost, the boomer heard the form of the snake slide from rock to rock of the uneven flooring.

The rattler was all of ten feet long and as thick around as a good-sized fence rail.

One square strike from those poisonous fangs and Pawnee Brown's hours would be numbered.

Yet the scout did not intend to give up his life just now. He still held his pistol, four chambers of which were loaded.

"If only I had a light," he thought.

Retreat was out of the question. A single sound and the rattlesnake would have been upon him like a flash.

It was only the darkness and the utter silence that made the reptile cautious.

Suddenly the scout heard a scraping on the rocks less than three feet in front of him.

The time for action had come; another moment and the rattler would be wound around his legs.

Crack! crack! Two reports rang out in quick succession and by the flash of the first shot Pawnee Brown located those glittering eyes.

The second shot went true to its mark, and the rattler dropped back with a hole through its ugly head.

The long, whip like body slashed hither and thither, and the scout had to do some lively sprinting to keep from getting a tangle and a squeeze.

As he hopped about he struck a match, picked up the lantern, shook the little oil remaining into the wick and lit it. Another shot finished the snake and the body curled up into a snarl and a quiver, to bother him no more.

It was then that Pawnee Brown paused, drew a deep breath and wiped the cold perspiration from his brow.

"By gosh! I've killed fifty rattlers in my time, but never one in this fashion," he murmured. "Wonder if there are any more around?"

He knew that these snakes often travel in pairs, and as he went on his way he kept his eyes wide open for another attack.

But none came, and now something else claimed his attention.

The cavern was coming to an end. The side walls closed in to less than three feet, and the flooring sloped up so that he had to crouch down and finally go forward on his hands and knees.

The lantern now went out for good, every drop of oil being exhausted.

At this juncture many a man would have halted and turned back to where he had come from, but such was not Pawnee Brown's intention.

"I'll see the thing through," he muttered. "I'd like to know how far I am from the surface of the ground."

A dozen yards further and the cavern become so small that additional progress was impossible.

He placed his hand above him and encountered nothing but dirt, with here and there a small stone.

With care he began to dig away at the dirt with his knife. Less than a foot of the cavern ceiling had thus been dug away when the point of the knife brought down a