The investigation was greatly simplified, at least on Whitey's side, by the fact that the bank of the Elkhorn offered very few possible landing-places, being high and steep, and there were few places that needed examination at all. On Injun's side, however, the ground required more careful scrutiny; but on neither side did anything develop. And before they were aware, they were almost at the Ross ranch.

The ranch lay just around a bend in the Elkhorn, on the left bank, and where the river was indented by a small bight, or pointed bay, that extended for several yards into the ranch property. The left bank of this bight was high above the water, and thickly covered by vines and shrubs that grew down to the water's edge, and many of them overhung the water, which was shallow at that point.

Once the boys were in sight of the ranch, the cautiousness of Injun manifested itself. He knew that the Ross outfit were none too partial to him, and he also knew that it would be unwise, if not unsafe, for him to be found so near to it. And riding down into the water, where the high bank concealed him from view, he rode cautiously around the bend of the bayou. Whitey, on the opposite bank, watched Injun's movements closely; and finally, in response to a signal, swam his horse across and landed under the high bank near Injun, whom he found examining the narrow shore or beach of the bayou under the high bank. The surface of the ground, which was sandy and covered with pebbles, had been undoubtedly disturbed recently; but it was seemingly impossible to tell by what. There were deep marks as though heavy planks had been pushed against it, and the ground about showed the hoof-marks of horses. These also were discernible in the mud under the shallow water. On the small beach it looked as though an attempt had been made to obliterate these marks, for the sand showed evidences of having been recently turned over in places.

Dismounting from his horse, Injun pulled aside the branches and bushes but nothing was revealed save the flat, gray face of the rock of the bank. Injun looked keenly at this for a moment; and then putting out his hand, found that it yielded to his touch! The rock wasn't rock at all! And going to one side, he found that what seemed to be rock was nothing more nor less than a heavy canvas, painted a dark gray to resemble rock, and smeared with mud and pieces of grass and leaves! So skillfully was this done, that it required close scrutiny to reveal it; and from a distance, even of ten or fifteen feet, it would never have awakened the slightest suspicion!

Lifting the edge of the canvas, Injun disclosed an opening in the face of the cliff nearly six feet high and of about the same breadth, and into this the two boys crept cautiously, leaving their horses on the narrow strip of beach near the entrance.

The interior of the cavern or tunnel was quite dark; but Whitey had been in the West long enough to learn that one of the most necessary things in a plainsman's equipment is matches. Injun, of course, had his flint and steel and tinder, but they would have necessitated the lighting of a torch, which would have been dangerous on account of the chance of discovery. They proceeded slowly along the tunnel, Injun examining it carefully, and a few yards from the entrance they found a number of very heavy planks so fashioned that they could be linked together to form a rude raft. The logs were wet and water-soaked. And the mystery of how the cattle got out of the river was no longer a mystery!

Whitey's first idea was, that having discovered this much, and thus definitely fixing the manner and means of the disappearance of the cattle, it would be a good thing to make a get-away while there was yet time, and report their discoveries to the Bar O outfit; and it would have been well for him if he had followed this plan. But Whitey was nothing if not courageous, and he was also impelled by an intense curiosity to fathom the rest of the mystery. If he could locate and identify the lost cattle, which would be easy on account of the brand, and possibly the one with the deformed hoof would be among them, his investigations would then be complete. But unfortunately for the success of this plan, there were certain difficulties in the way which neither Whitey nor Injun could foresee; and certain contingencies happened which had their fortunate side as well as their unfortunate.

The two horses had been left untied on the narrow strip of beach outside the tunnel entrance. Left alone, Injun's cayuse would have stood there for many hours. But Whitey's horse, Monty, was not, as yet, so well trained; and after a time began to be restless. The spot was not exactly an attractive one in which to stand for an indefinite time, and Monty finally retraced his steps around the bend and out of the bayou where there were grass and sunshine. With such an example, the pinto slowly followed; but scarcely had Monty come around the bend when a rattler that was sunning himself on the rocks sounded his warning, and Monty gave a frightened snort and proceeded to "beat it" away from there in a panic.

When a horse is badly frightened and starts to run in a panic, the first thought that comes into his head is to get home as fast as he can; and Monty proceeded to put this idea into execution. He tore along the bank, and at the proper place swam the stream, and was soon well on his way back toward the Bar O ranch.

By the time Injun's horse got around the bend the rattler had disappeared, and therefore he was not thrown into any panic, as Monty had been. Monty was not in sight either; and so, although he probably wondered what had become of his pal, he climbed the bank and proceeded to graze on the sweet grass, plainly visible from the windows of the Ross ranch!