and then, with a resounding splash, the animal and its living burden disappeared beneath the surface of the river and out of the sight of the rascals on the opposite side of the canyon.
"That settles him," cried one of the horse thieves, grimly. "He was a fool to follow us."
"Maybe he'll escape," ventured a second.
"Wot! Arfter sech a plunge?" returned the first speaker, sarcastically. "Wall, hardly, ter my reckonin'."
They shifted their positions on the brink of the opening, but try their best, could see nothing more of the young man or the mare.
It was now growing darker rapidly, and fifteen minutes later, satisfied that Allen had really taken a fall to his death, they continued on their way.
And poor Allen?
Down, down, down sank the mare and her hapless rider, until the very bottom of the river was struck.
The swiftly flowing tide caught both in its grasp, tumbled them over and over and sent them spinning onward. Allen's grasp on the saddle relaxed, and as it did so the young man lost consciousness.
How long he remained in this state Allen never knew. When he came to he was lying among brush, partly in the water and partly out.
He attempted to sit up and in doing so, slipped back beyond his depth. But the instinct of self-preservation still remained with him, and he made a frantic clutch at the brush and succeeded in pulling himself high and dry upon a grassy bank.
Here he lay for several minutes exhausted. He could not think, for his head felt as if it was swimming around in a balloon.
At last he began to come to himself and after a bit sat up to gaze about him. But all was dark and he could see little or nothing.
He remembered the great plunge he had taken and wondered what had become of Lilly. He called her with all the strength of his enfeebled lungs, but received no response.
"She must have been killed," he thought. "Poor Lilly! But had it not been for the protection her body gave me it is more than likely that my life would have been ended, too!" and he shuddered to think of his narrow escape.
It was nearly half an hour before Allen felt strong enough to rise up. His head felt light, and for a while he staggered like an intoxicated man.
He knew he was down in the canyon, and some distance below where the bridge had been. He wondered how he could ascend to the top of the rocks which presented themselves on the two sides.
"I can't climb up in this darkness," he said half aloud. "I might slip and break my neck. I had better walk along and hunt for some natural upward slope."
He started off along the river side, the top of the canyon towering nearly a hundred feet above his head as he proceeded. The opening gradually grew narrower, and with this the distance between the rocks and the water decreased, until there was hardly room left for Allen to walk.
"I must have made a mistake," was the mental conclusion which he arrived at. "I should have gone up the river instead of down. The chances are that I can't go over a hundred feet further, if as far."
Soon Allen came to a halt. The ground between the wall of the canyon and the water ceased just before him. Beyond the steep and bare rocks ran directly downward into the stream.
"That settles it," he muttered, in great disappointment. "All this traveling for nothing. And it's getting night over head, too! It's a shame!"
Allen paused to rest, for in his weak condition the walk had tired him greatly. Then he started to retrace his steps.
Hardly had he taken a yard's advance, when his left foot slipped upon a round stone. He was thrown over on his side, and before he could save himself went plunging headlong into the stream!
He essayed by every means in his power to regain the bank, but in vain. The current of the river was extra strong at this point – the width of the course having narrowed down – and before he could clutch the first thing he was carried to where nothing but the steep and slippery rocks presented themselves.
Vainly he put out his hands to stay his progress, vainly he tried by every means in his power to obtain some sort of hold on the rocks.
And now the surface of the river grew blacker as the rocks on both sides began, seemingly, to close in over his head.
He was almost tempted to cry out for help, and took a breath for that purpose, but the sound was not uttered. What would be the use? Not a soul would hear him.
On and on went the young ranchman, the waters growing more cold each instant and the prospects more gloomy. He was half tempted to give himself up for lost.
It was an easy matter to keep himself on the surface, for he was really a good swimmer, but now the current was so strong that he could scarcely touch either side of its rocky confines as he was swept along, he knew not where. Allen had never explored this stream, and this to him made the immediate future look blacker than ever.
"If it ends in some sort of a sink hole, I'm a goner sure," he thought. "But I never heard of such a hole up here among the mountains, so I won't give up just yet."
Hardly had the thought occupied his mind when, on looking up, he saw the last trace of evening fade from sight. The river had entered a cavern! He was now underground!
It may well be imagined with what dismay Allen, stout-hearted as he was, viewed the turn of the situation. Here he was being borne swiftly along on an underground river, he knew not where. It was a situation calculated to chill the bravest of hearts.
All was pitch black around and overhead; beneath was the silent and cold water, and the only sound that fell upon his ears was the rushing along of the stream.
As well as he was able, Allen put out his hands before him, to ward off the shock of a sudden contact of any sort, for he did not know but that he might be dashed upon a jagged rock at any instant. Then he prayed earnestly for deliverance.
On and on he swept, the stream several times making turns, first to one side and then to the other. Once his hand came brushing up to a series of rocks, but before he could grasp them he was hurled onward in an awful blackness.
A quarter of an hour went by – a time that to the young man seemed like an age – and during that period he surmised that he must have traveled a mile or more.
Then the current appeared to slacken up, and he had a feeling come over him as if the space overhead had become larger.
"This must be an underground lake," he thought. "Now if I – Ah, bottom!"
His thought came to a sudden termination, for his feet had touched upon a sloping rock but a few feet below the surface of the stream. The rock sloped to his right, and, moving in that direction, Allen, to his great joy, soon emerged upon a stony shore.
He took several cautious steps in as many different directions and felt nothing. He was truly high and dry at last.
This fact was a cheering one, but there was still a dismal enough outlook. Where was he and how would he ever be able to gain the outer world once more?
CHAPTER VII.
The Cave in the Mountain
Allen was too exhausted to do more than
