The hour, the surroundings, and the utter mystery of the whole affair combined to make the sudden appearance and vanishment of the great shadowy shapes the more inexplicable, not to say alarming. Small wonder was it that the inquiring faces that turned toward each other were a trifle whiter than usual.
"What do you make of it, Pete?" asked Jack.
"Stumped, by the big horn spoon!" was the expressive response.
"No doubt, some natural phenomena, with a simple explanation," came from the professor. It was noted, though, that his angular form seemed to be somewhat shivery as he spoke, and that his teeth chattered like dice rattling in a box.
"Natural phe-nothings!" burst out Pete. "The things, whatever they was, were as solid as you or me."
"How was it they didn't make any noise, then?" inquired Ralph, practically.
"Waal, son, you jes' take a run on the bunchgrass, and you'll see that you won't make no racket, nuther."
Ralph did as he was directed, and it was really wonderful how silently he sped over the springy vegetation.
"Maybe it was somebody putting up a scare on us," suggested Walt, rather lamely.
"They couldn't rig up anything as big as that," said Jack decisively, "besides, there's another thing—I didn't tell you because I thought I might have been mistaken, but I saw those same things this afternoon."
"What?" went up in a perfect roar of incredulity.
"Say, is this some kind of a josh?" asked Coyote Pete suspiciously.
"Never more serious in my life," Jack assured him, and then went on to relate the strange experience that had befallen him when he had poked his head out from under the saddle in the sand-storm.
"If they weren't so enormous, I should say they was horses," said Pete; "but the biggest horses that ever growed never even approached them critters—spooks, er whatever they are."
"There are giants among men," suggested Walt, "why shouldn't there be giants among spooks, too?"
"You get to Halifax with that spook talk," said Coyote Pete scornfully. "I'll bet my Sunday sombrero that whatever them things is, there's some sore of human mischief back uv it. But what is it? Who put it up?"
"Yes, and what for, and why?" laughed Jack. "I tell you, fellows," he went on, "it's no use of our racking our brains to-night over this. The best thing we can do is to set a watch. Then, if they come again, we can try a shot at them. If not, why then in the morning we'll make an investigation; eh?"
"Durn good advice," grunted Coyote Pete. "Now, I'd suggest that ther perfusser takes ther fust watch, and——"
"No, no, my dear sir; really, I—I have a cold already. A-hem—ach-oo!"
The man of science, it seemed, had really developed serious bronchial trouble in record time.
"Why, professor," said Jack mischievously, "haven't I heard you say that you'd like a chance to investigate such a phenomenon as this?"
"Hum, yes—yes, my young friend. I may have said so, yes. And any other time I should be only too pleased to—Good Land! what's that?"
With the agility of a grasshopper, the professor had jumped fully three feet, as one of the pack-burros, nosing about behind him, accidentally butted him in the small of his back. The others burst into a roar of laughter, which they could not check. The professor, however, adjusted his spectacles solemnly and looked about him with much dignity.
"I thought I saw a book I had dropped, almost in the fire," he explained glibly, "so I jumped to get it before a hot ember fell on it."
"I had no idea you could jump like that, professor," laughed Jack. "You should have gone in for athletics at Stonefell."
It was finally decided that Walt and Ralph should stand the first watch, and Coyote Pete and Jack the last part of the night. The professor, after carefully drawing tight the curtain of his tent, "to keep the cold out," as he explained, retired. Soon after, Jack and the cow-puncher also went to bed till the watch should summon them to go on duty in their turn.
But the night passed without any reappearance of the strange shapes which had so upset the tranquility of the little camp, and, viewed in the fresh light of a new and glorious day, somehow the affair did not seem nearly so ominous and awe-inspiring as it had the night before. Breakfast, as you may imagine, was speedily disposed of, and, having seen to the stock, the party started out to explore the mesa itself.
As has been said, the side upon which they had camped the night before was nothing but a sheer cliff. Under the guidance of Coyote Pete, they now set out to encircle the strange precipitous formation. Their hearts beat high, and their eyes shone with an aroused sense of adventure as they strode along.
The professor carried with him a small volume containing a partial translation of the symbols and sign language of the ancient tribe whose domains they were about to invade. Jack had a coil of stout, half-inch manila rope, about two hundred feet in length. Walt Phelps' burden was a shovel, while Ralph Stetson carried an axe. All bore with them their revolvers, and Coyote Pete carried, in addition, a rifle.
"Are you afraid of anything?" the professor had asked him, as he noticed the sun-bronzed plainsman pick up this latter weapon.
"Waal," Pete had rejoined, with a portentous wink at the boys, "you never kin tell in this wale of tears what you're a-goin' up aginst—queer shapes, fer instance."
As they strode along, naturally the subject of the shadowy forms which had alarmed them the night before arose. Jack would have liked to investigate them right then and there, but, after all, he decided with the rest of the party, that an exploration of the mesa was the first thing of importance to be accomplished. And an interesting sight the great abandoned aboriginal beehive, was, as they rounded the inaccessible side and emerged upon the portion which faced toward the northwest.
Pete's recollection had not played him false. There was a rough pathway constructed up its face upon this side, and at the top were three tiers of holes bored in the rock face. These were evidently intended for windows, as a larger aperture was just as evidently meant for a door. The path, which zig-zagged up the face of the mesa was about eight inches in width, not more, at its base, and varied—so far as they could see from below—from that breadth to a foot, as it grew higher.
From the base to the summit the mesa was probably about one hundred and fifty feet in height, the windows not commencing till within twenty feet of the top. Its length at the base was, roughly, three hundred feet, and its thickness varied from three hundred feet or more at the center, to a few feet at each end. Roughly, then, its basic outline was that of an irregular parallelogram, while its profile was that of a flat-topped cone. For some moments the little group stood in silence as they gazed up at the yellowish-gray walls of the once-active mound.
Finally, recovering from their reverie, they set out after Coyote Pete to scale the narrow pathway leading to the summit. But, as the cow-puncher set his feet on the lowermost part of the path, he gave an exclamation of astonishment and pointed downward.
There in the dust was a footprint,—several of them, in fact.
It was a startling discovery in that isolated part of the desert to come upon the traces of human occupancy. Robinson Crusoe on his desert island could not have looked any more astonished at the imprint of the savage's sole, than did Coyote Pete. He stood looking down speechlessly at his discovery, while the others crowded about him, asking a dozen questions at once.
"If the sand-storm had hit this section, we'd been able to form some idee of how long ago them hoofs was planted there," said Pete; "but as it is, ther feller who wondered how ther apple got in ther dumpling didn't hev a harder problem than the nut we've got to crack."
"There must have been several of them," said Jack, who had been gazing in the dust, which lay thick on the pathway to the summit of the mesa.
"A dozen at least," nodded Pete. He tipped back his sombrero and scratched his ruffled hair, fairly at a standstill to account for what they had encountered.
"Mightn't it have been prospectors?" asked Ralph.
"Might hev bin, yes," agreed Pete; "but, fer one thing, my son, prospectors don't usually travel in dozens."
"Hum—that's so," assented Jack, who at first had greeted Ralph's suggestion eagerly.
"Look here!" cried Ralph suddenly, holding up a glittering object which he had just discerned in the bunch-grass at the base of the mesa.
"What is it, my boy?" inquired the professor.
Ralph extended the object for their inspection.
"A strange coin," cried Walt.
"Not so blamed strange, either," said Pete, picking it off the boy's palm and examining it. "It's a Mexican peso."
"Then the men who were here were Mexicans?" cried Jack.
"Not so fast, my boy," admonished Pete. "Might as well say that every feller who finds a Canadian dime in his pocket is a Kanuck. Say," he suggested suddenly, "suppose you boys jes' see if you can find any tracks around the base of the mesa."
They scattered and looked carefully about them, but the bunch-grass grew in quite a broad belt all about, and no footmarks could be discerned. Nor did a careful examination of the grass show any broken or trampled blades, as would have been the case had ponies been there recently.
"That decides it," announced Pete, after this last fact had been ascertained, "whoever made those foot-marks wasn't here recent, that's a fact. But who could they have been, and what brought them here?"
"Maybe Indians," suggested Ralph sagely.
"Yep, if Indians wore boots, which they don't," grinned Pete, while poor Ralph colored to the roots of his hair over the general laugh that arose at his expense.
"I think," announced the professor finally, "that it would be our best plan to go ahead exploring the mesa. After all, there is nothing here that can hurt us. Those ruffians of Black Ramon's have been driven out of the country, and, anyway, they would not be likely to come here. As for Indians, their reservation is many miles to the north-east. Whoever was here, was either on a scientific quest, like ourselves, or else unfortunately lost in the desert."
"Jes' ther same," grunted Pete, in a low voice that nobody overheard, "I'd like ter know what all this means: Big, shadowy shapes flitting around in ther night, and footsteps here in ther mornin'. It don't look right."
He took a swift glance all about him. In every direction lay the desert—glittering, far-reaching, lonely as the open sea. The only break in the monotony came to the south—on the border—where stretched the rocky, desolate ridge.
"No one wouldn't come here without an object," reasoned Pete to himself, as they began the ascent of the narrow, tortuous trail, "now, what in thunder could that objec' hev bin?"
"Magnificent indeed!"
The words, falling from the professor's lips, echoed hollowly against the walls of the lofty, vaulted chamber in which the adventurers found themselves, after traversing a narrow passage leading inward from the causeway.
The walls of this chamber, which must have been fully thirty feet in height at its greatest altitude, were formed of the soft rock, out of which it had been excavated apparently uncounted ages before. They were daubed with grotesque figures in faded, but still discernible, colors. Most of these figures had to do with scenes of violence, and in almost all of them the figure of what appeared to be an enormous rattlesnake, with human head and arms, predominated.
Among the mural decorations were some that puzzled the professor considerably. They were crude drawings of men in what appeared to be intended for boats. The professor found these inexplicable. The very idea of boats in that arid spot seemed absurdly out of place. Why, then, should the mesa-dwellers have depicted them?
Light was furnished to the chamber by an irregularly shaped hole in the roof above. Although there was plenty of illumination, it had yet been some moments before the adventurers, coming out of the brilliant sunlight outside, grew used enough to the gloom to make out their surroundings. When they did so, the first words uttered were those of the professor recorded above.
Like some queer, long-legged bird, the man of science, with a giant magnifying glass held up to his eye, sped hither and thither on his long, angular limbs, inspecting minutely the drawings and crude attempts at decoration. Already he had out his tape-measure and sketch-book, making observations and recording measurements. Presently, however, he recalled himself from the first heat of his enthusiasm.
"After all," he said, "we shall have plenty of time in which to explore this chamber, which seems to have been used as a council hall. Let us examine the remainder of this remarkable place."
"You may well call it that, perfusser," grunted Pete. "It's remarkable fer the dust thet's in it, if nothing else. But what I'd like to know," he added to himself, "is jes' whar the owners of them footsteps vanished themselves to."
Which brings us to a remarkable discovery, made a few moments before our party had entered the "Council Hall," as the professor called it.
As you may imagine, they had traced the footsteps with some care, hoping to come upon a solution of the mystery of their origin. Picture their astonishment, then, when you are told that the footsteps abruptly vanished at the summit of the zig-zag trail. Although dust lay thick on the chambers within the mesa, not a solitary foot-mark marred its soft gray surface. With the exception of the numerous footsteps on the trail to the summit, there was no other sign of human visitors.
Like most old plainsmen and all wild animals, Pete was suspicious of anything he couldn't understand, and it certainly did seem inexplicable that a party of men should have visited the mesa and contented themselves with running or walking up and down the causeway outside, or promenading the summit. Such, however, appeared to be the only explanation, and as such they were forced to accept it.
But such speculations as these were far from monopolizing the minds of the professor and the boys. They eagerly traversed chamber after chamber, finding these latter to be small "apartments," so to speak, giving upon a common passage just beyond the "Council Hall." The professor told them that each of these small chambers was formerly the home of an aboriginal family. In the floor of the passage he pointed to numerous bowl-like holes, which, according to him, had been used for the sharpening of spears and arrow heads.
In some of the small chambers specimens of rude pottery were found, all ornamented with the same figure of the human-headed rattlesnake. Evidently the form represented must have been a deity of the tribe. Each of the small chambers was lighted by one of the holes cut in the face of the cliff, which they had noticed from below. The boys darted in and out of the various rock chambers, like ferrets in a rabbit warren, followed at a more leisurely pace by the professor and Coyote Pete.
"Maybe we'll find some treasure," suggested Ralph Stetson, as, with flushed faces, plentifully begrimed with dust, they paused in the last of the rocky chambers.
"Say, you've got treasure on the brain, ever since we found that chest of Jim Hicks' in the passage-way under the old mission, and started our bank accounts," laughed Jack. "You must be forgetting that this mesa has been visited frequently by cattlemen and wandering prospectors."
"Well, I should hardly call it frequently, Jack," put in Professor Wintergreen, who was now standing with Coyote Pete at his elbow, in the narrow entrance to the rocky chamber.
"Nope," added Coyote Pete; "you can bet your boots we didn't come here except when we had to. In the past, though, it made a mighty good watering-place for the cattlemen driving from one section of this country to another. Sence they cut up that land over to the westward inter farms, though, the big cattle drives have stopped, and I don't suppose any one's bin around here for a long time, 'cepting those varmints whose feet-marks we seen."
"How do you know they are varmints?" laughed Walt Phelps.
"Don't see what business they'd hev here otherwise, and——" began Pete, but a perfect tempest of laughter at his expense drowned the rest of his speech.
"Well, now that we seem to have pretty well explored the habitation part of the mesa, let us make our way to the summit," suggested the professor.
With a whoop and yell, the excited boys followed the suggestion at once, and a dash up the narrow causeway followed at imminent risk of one of another losing his footing.
"Hey, hold on thar!" yelled Pete, as they dashed upward, "we don't want no funerals here, an' it's er drop of more'n a hundred feet to ther ground."
This rather checked the boys' enthusiasm, and they went more slowly thereafter.
The summit of the mesa was found to consist of a small plateau, about a quarter of an acre in extent, perfectly bare, and shaped like a saucer. Near the center was the hole which gave illumination to the council hall below them, while in a spot almost exactly in the middle of the queer elevation, was a rough, square erection of sun-baked brick. This was about twelve feet in length, five feet in height, and six feet or so through. Apparently it had once been a kind of an altar. The professor thought this assumption tenable, as it was known that the aborigines who had once inhabited the mesa had been sun-worshipers.
"Ugh!" shuddered Jack, as he gazed at the altar. "And they used to offer human sacrifices here."
"I think it altogether likely," said the professor calmly; "probably that altar has witnessed the immolation of more than a hundred victims at a single tribal ceremony."
Ralph Stetson was clambering up on the altar as the professor spoke, but at hearing these words he hastily descended again.
"I guess I'll defer examining it till some other time," he said decidedly.
From the summit of the mesa a wonderful view could be obtained. At that altitude the rocky, desolate range of sierras to the south could be seen clearly, although a mile or so distant.
"Thar's the border yonder," said Pete, pointing.
"And over across there is father, I guess," said Jack. "I hope he found everything at the Esmeralda all right."
"Sure he did," said Pete confidently. "I tell you, these greaser uprisings don't amount to a busted gourd. Mister Diaz's tin soldiers come along, and 'pop-bang! Adios!' It's all over."
"But I have heard that in this case the insurrectionists of Northern Chihuahua are exceptionally well provided with arms and ammunition," objected the professor. "The American government can't make out from whence they are supplied with guns and munitions of war."
"Huh, where'd they git 'em from, I'd like to know?" snorted Pete. "The border is well guarded at any point where they would be likely to ship 'em across, and——"
"How about theunlikelypoints?" inquired the professor amiably.
"Um—ah—well," began Pete, somewhat stumped by this last, "I don't see what that's got to do with it."
"But I do. Mexicans, my friend, are, as you should know, a cunning race. Moreover, those of them who dwell along it know the border far better than any white could ever hope to. By the admission of our own secret agents, it has hitherto been impossible to find how the arms, which the Chihuahua rebels are receiving, can reach them. It is obvious, however, that there must be some way in which they do, hence——"
"Waal, perfusser, hev it your own way," grunted Pete, rather red and angry. The professor's logic did indeed seem unassailable. The rebels of Northern Chihuahua were getting arms—but how? The cow-puncher and the boys recalled now a visit made to Mr. Merrill's ranch some weeks before by a party of United States secret agents.
The men were puzzled and angry over their failure to locate the "leak." Somehow arms were being shipped across the border into Chihuahua from American soil, but just how had hitherto baffled all the efforts of their ingenuity to discover.
"There, there, don't be so easily offended," counseled the professor, perceiving Pete's palpable irritation. "After all, the matter has nothing to do with us. We are here to measure the mesa for scientific purposes, not to get into arguments over how a band of insurrectos are getting their arms. Come, boys, to work. Let us begin at the top, by measuring the altar. Suppose, Jack, you lay the tape on it, while I make a rough field sketch of the structure."
The boys, now over their first repulsion to having anything to do with the altar, about which such grisly memories clustered, eagerly began to carry out these orders, while Coyote Pete seated himself on the side of the summit overlooking the travelers' camp below, and amused himself by throwing small bits of detached rock down at the unoffending One Spot, Two Spot and Three Spot.
The base of the altar being duly measured and recorded, Jack, tape in hand, followed by the others, clambered up its rough sides, which afforded an easy foothold, for the purpose of ascertaining the dimensions of the top. To the lad's astonishment, however, there was no summit. That is to say, the altar was hollow.
The professor exhibited considerable scientific excitement on hearing this. The man of science had been greatly puzzled over the total absence of any traces of the human sacrifices he knew must have taken place there. He now hailed Jack eagerly.
"Are there not some bones or traces of sacrifices inside it, my boy?" he inquired excitedly.
"Nary a bone," shouted Walter cheerfully.
"Hold on, though," cried Jack. "There are some queer-looking things down in one corner."
Lowering himself inside the altar, he made for one corner of the erection, in which he had spied a heap of fragile-looking bones of some kind.
"Skeletons of snakes!" he cried, holding up one of these for the inspection of the professor, who had by this time hoisted his bony frame over the top of the altar and now stood beside them.
"That's right, my boy; they are serpents' skeletons. Doubtless in their sacrificial ceremonies these people also offered up rattlesnakes, which seem to have been a sort of sacred reptile among them; much as, in a sense, the cat was sacred to the ancient Egyptians, and the python is worshiped in certain parts of India."
"But, professor," protested Jack, "if, as you say, numerous human sacrifices were offered here in the past, why do we not find any human remains here?"
"Who can say, my boy? Many of the habits of these pre-historic peoples are veiled in mystery. We can only surmise and reconstruct. They may have burned them or disposed of them in some other way."
"Say!" exclaimed Ralph suddenly. "This floor sounds to me as if it was hollow; maybe there's a chamber or something underneath."
The boy, who had been stamping about with a vague sense of making some such discovery, hailed them with excited looks.
"Hollow, you say?" asked the professor, with every appearance of deep interest.
"Yes, listen!"
Again Ralph stamped about. There was no question about it—the stone-paving, of which the floor of the altar was formed, gave out an unmistakably hollow sound.
The professor was down on his hands and knees instantly, searching about, like a hound on the scent. In the meantime the others stamped about in other parts of the interior, but only where Ralph's feet had given out the hollow sound did the floor appear anything but solid.
"Queer!" exclaimed the professor, as, after a considerable search, he rose to his feet covered with dust and streaming with perspiration, "there should be some sort of trap-door here, to judge by the sounds, but so far as I can see, the joints between the pavement are perfectly tight, and I can find no ring or lever which might open such an aperture."
"Perhaps——" began Ralph, but he was interrupted by a sudden wild yell from Pete.
"Wow! Yee-ow! Come here quick, everybody!"
Leaping and scrambling over the top of the hollow altar to the best of their abilities, the four explorers found their cow-puncher friend dancing wildly about on the edge of the mesa, in imminent peril of tumbling over altogether. He was wildly excited, and, as they emerged, he pointed down over the cliff edge.
"Whatever is the matter?" exclaimed Jack, regarding the antics of the usually staid cow-puncher with amazement.
"The stock! Look at the stock!" yelled Pete.
Peering over the edge at the bunch-grass belt in which their ponies were tethered, the adventurers saw a spectacle which might well have been calculated to excite the cow-puncher. One Spot, Two Spot and Three Spot were tearing round and round at the end of their tethers, in the wildest alarm, evidently, while the cayuses were stamping and snorting, with distended nostrils and wild, frightened eyes.
"What's the matter with them?" gasped Walt, astonished at the sight, as well he might be. The desert was as empty as ever, and there was no sign of anything in the rocky hills to the south that might have excited their alarms.
"Thet's jes' it," said Pete. "What is the matter with 'em? They ain't actin' up thet er way fer nuthin', you kin bet."
"Something must have scared them," said Jack. "Maybe it was those rocks you were throwing down."
"No, it warn't that, son. Ole One Spot he looked up here a minute ago, and giv' his eye a knowin' wink, as much as ter say: 'Go ahead; I know you won't hurt us.' No, siree; it's suthin' they've smelled out, er seen, that's given 'em the scare of their young lives."
"Maybe it was something on the other side of the mesa. Let's go and look," cried Jack.
Followed by the others, he ran across the flat summit, but an earnest inspection of the surroundings on that side failed to reveal any explanation for the animals' sudden terror. For all the strange objects that lay about them, they might have been in the middle of a desolate ocean.
"No wonder they call this the Haunted Mesa," snorted Pete. "I tell you, perfusser, ther sooner you git them thar measurements a-measured, and we're hiking out of this neck of the woods, the better I'll be pleased. 'Tain't natural, all these queer goings on."
"Maybe a coyote or something scared them," suggested Ralph.
"And them used ter seeing 'em every day," scoffed Pete. "Guess again, son. It takes something with hoofs, horns and red fire about it to scare a burro, and you kin bet your Sunday sombrero on that."
"Well, I propose that we adjourn the meeting till after dinner," laughed Jack; "all in favor, will signify by saying 'aye.'"
The chorus that answered him left no doubt of "the sense of the meeting," and a rapid descent of the mysterious mesa was begun. A good meal was not long in being prepared, thanks to Coyote Pete's skill as a camp cook. Seated over their dinner, the main topic of conversation was naturally the unaccountable occurrence of the morning. But although a score of explanations were advanced, nobody could hit on one that seemed to fit the case.
"This water is singularly pure and sparkling,"' said the professor finally, by way of changing the subject, and holding up his full tin cup.
"Yep; I remember hearing old cowmen say that there's no water in New Mexico any better than this from the Haunted Mesa," said Pete, stretching himself out, and lighting his inevitable after-meal-time pipe. "Though that ain't sayin' a heap," he admitted.
"Wonder how those old what-you-may-call-ums ever managed to dig such a well?" questioned Ralph.
"Comes to my mind now," said Pete, "that it ain't exactly a well. An old Injun that used ter hang around with the Flying Z outfit tole us oncet that thar was a subterranean river flowed under here, and that once upon a time afore all the country dried up, considerable more water came to the surface here than there does now."
"A subterranean river?" asked the professor, at once interested.
"Yes, sir," rejoined Pete, "and not the only one in the West, either. There's one in Californy that flows underground fer purty near fifty miles, as I've heard tell."
"This is most remarkable," said the professor. "I, too, have heard of subterranean rivers in this part of the world, but I have never had the opportunity to explore one. Did this Indian you speak of ever tell you where this river emerges?"
"He said it come out some place across the frontier in Chihuahua; I don't jest rightly recollect where," said Pete carelessly, as if the subject did not interest him much, as indeed it did not.
"I don't see what use a subterranean river is to anybody, anyhow," he went on. "If it was on top, now, it might be some use."
"But this is most interesting," protested the professor, while the boys lay about with their chins propped in their hands in intent attitudes. "Then, too, if this river exists, perhaps it is even navigable."
"Why, professor!" exclaimed Jack. "Is it not possible that it was to this river that those drawings of boats that interested and puzzled you so much had reference?"
"Quite possible, my boy," agreed the man of science.
"I wish we could find some way of getting down into it," said Ralph wistfully, poking at the ground, as if he thought he might force an entrance that way.
"Thar you go," laughed Pete. "Giv' you boys a cayuse, an' you'll ride him to death. I jes' mentioned that a lying, whisky-drinking old Injun had sprung a pipe-dream about a lost river, and thar you go navagatin' it in a Coney Island steamboat."
The boys could not help bursting into a laugh at the cow-puncher's whimsical way of talking. The professor joined in, too, for none realized better than he did that for a moment he, too, had been quite carried away by the idea.
"I expect that it is as you say, Pete," he agreed. "These Indians are most unreliable people. If anybody was to believe all the weird legends an Indian tells him, he would spend the best part of his life on wild-goose chases. Why, the Indians of the Mojave desert in California can even tell a circumstantial story about a buried city of Mojave. According to their contention, a great flood, occurring long ago, wiped it out and buried it in the sands of the desert."
"Has any one ever tried to find it?" asked Jack.
"Many expeditions have been fitted out for the purpose, my boy," was the rejoinder, "but so far no trace has ever been found of it, and it is, no doubt, like the lost river of which Pete was telling us, a mere myth."
"I didn't say it was a miff," protested Pete. "I jes' said I didn't believe it."
The remainder of that afternoon was spent in making more measurements and sketches of the interesting mesa, and the boys, on their own account, conducted a search for a possible entrance to the lost river. But, as may be supposed, they found none.
"I guess as romance-seekers we are not a success," said Jack, as at sun-down they prepared to quit. "Just think, what a proud bunch we'd have been if we could say we—The Border Boys—discovered the lost river of the mesa dwellers."
"We might be a sorry bunch, too," amended the practical Walt. "I tell you, Jack, I don't want anything to do with lost rivers, especially when they are underground."
"Walt, the spirit of adventure is lacking in you," laughed Jack. "You'd never make a Don Quixote——"
"A donkey who?" asked Walt innocently.
"Oh, you're the limit," chuckled Ralph, going off into a roar of laughter at the ranch boy's expense.
That evening the animals' pasture was changed to the opposite side of the mesa, where they could find fresh grass. The camp, however, was left as it was. After supper watches were assigned, as usual, the latter part of the night guardianship falling to Coyote Pete and Jack once more. When, soon after midnight, Walt and Ralph Stetson aroused them, there was nothing much to report except that One Spot had engaged in a spirited kicking match with his brethren. Outside of that, all had been, to quote Walt:
"Quiet along the Mesomac."
"We'll patrol round the whole mesa," said Coyote Pete, as he and Jack shouldered their rifles, "meeting by the stock on the other side."
After a few words more, the two sentries strode off into the darkness in different directions, meeting, as arranged, by the stock. Neither had anything to report, and in this way they kept up the night watch for an hour or more. They had met for the sixth time by the tents containing their sleeping comrades, when from the opposite side of the mesa came a shrill neigh of terror, followed by sounds of wild galloping and snorting.
"Something's up!" shouted Pete, as, with his rifle in readiness and followed closely by Jack, he tore around the mesa to ascertain the cause of the trouble.
As the two sentries emerged into view of the spot in which the stock had been tethered, they came upon a spectacle which, for a moment, caused them to recoil as abruptly as if a deep canyon had suddenly opened up before them.
That which brought the two—the plainsman and the lad—to such an amazed halt was nothing more nor less than the sight of the huge forms which had appeared to Jack in the sand-storm and which had given them such an alarm the night before, and which doubtless, as they now viewed it in a flash of intuition, had almost stampeded the stock while their owners were exploring the top of the mesa. But Coyote Pete was not the man to remain long rooted in astonishment.
With one quick jerk, he raised his rifle, and a vivid spatter of fire followed. As the report died out, one of the great forms sank to the ground with a scream that sounded almost human. The others glided off in the same direction as they had the night before, and vanished in the same mysterious way, before the thunderstruck Jack could get a shot at them.
"They're real, at any rate," exclaimed Coyote Pete, showing in his tone of relief, that until the great shadowy mass had sunk before his bullet, he had had some doubts of that fact.
"W-w-w-w-what is it?" came a frightened voice at their elbows, and, looking around, they saw the professor, in pajamas striped like a barber's pole, gazing apprehensively about him. Close behind him came Ralph Stetson and Walt, their weapons clasped determinedly, and evidently ready to face whatever emergency the sudden shot had betokened.
"Yes, what is it—Indians or bears?" demanded Ralph, entirely forgetful of the fact that bears are not wont, as a rule, to roam the barren desert.
"Dunno, but we'll see in a minute," said the cow-puncher, in answer to the excited questions. Followed by the rest, he made his way forward to where the great bulk that he had shot lay still and motionless on the ground. Even Jack owned to a slight feeling of apprehension as they neared the great form,—harmless as, whatever it might be, it had now become.
As for the stock, they were still plunging wildly about and snorting in a terrified fashion, and, had it not been for their stout raw-hide tethers, they would undoubtedly have stampeded.
Drawing a match, Pete held it high as he neared the stricken bulk outstretched before them. The next minute he gave an astonished cry:
"A camel!"
"Awhat!" gasped the entire group in unison.
"Jes' what I said, a backterian camel," reiterated Pete, striking another match.
They could all see then that he spoke the truth, astounding as it seemed. The creature that lay still before them, a bullet through its brain, was a veritable, undoubted specimen of the Bactrian species.
"But—but—great heavens!" cried Jack, hardly able to believe his eyes, "how,—what——"
"What on earth is a camel doing out here on the New Mexican desert?" the professor finished for him.
"Going eight days without a drink," suggested Ralph in an undertone; but none of the party was in a mood for humor just then.
It was Pete who solved the mystery.
"I've got it," he exclaimed, "and I'm a plum-busted idjut not to have thought uv it afore; I've hearn about 'em often enough. This here backterian camel must be one of that bunch of Circus Jesse's."
"Circus Jesse! Who was he, or she?" asked Jack.
"Why, he was a feller what owned a big eastern circus, but owned a ranch out here as well. It struck him one time that if camels was good for transportation purposes over the Sahara desert they ought ter be just as good here. So, what does he do but start a camel express from Maguez ter Amadillo over the border, with some of the backterians frum his circus."
"And didn't it work?" asked Ralph.
"No. That is, it did fer a while, till ther novelty wore off, and then folks went back ter ther old reliable mule or burro. Circus Jesse, he got so blamed sore, that one fine day he turned the whole shootin' match of his backterians loose, and packin' his trunk, let the country, and resolved in futur' ter stick ter his circus."
"Was that long ago?" asked Jack. "I shouldn't have thought the creatures would have lived long without being recaptured."
"It's about five years since Jesse got out, I reckon," rejoined Pete, "an' fer a while camel-hunting was a popular sport. By an' by, however, they got so wary no one could get near 'em, and, except fer a scare they'd throw inter a prospector now and ag'in, we never heard no more of 'em. I'd clean fergotten all about 'em, till I made this one inter cold backterian meat."
"I suppose they found food and water here and regarded the Mesa as their own property," declared Jack.
"That's about it. This is a place that's seldom visited, and I guess they just figgered out that they'd found a happy home."
"But what became of the rest of them?" asked Ralph, who had been apprised by Jack of the strange vanishment of the dead creature's mates.
"Must uv gone down that draw I noticed frum ther top uv ther mesa to-day," explained Pete. "Yer see, frum here, it would look as if they vanished inter the solid earth when they entered it, bein' as how you can't see there's any kind of a gully there till you get up high."
The next morning this was found to be the true explanation. Tracks on the bottom of the gully showed plainly how the strange desert wanderers had effected their disappearance in such a startling manner. But it was some time before Pete could sit down to a meal without being reminded of his "fire-spouting spook," which had cast such alarm into the camp the first night. The boys spent a week more at the mesa, during which time Professor Wintergreen obtained voluminous notes on one of the most interesting specimens of its kind in the south-west.
The days passed tranquilly, and, with the exception of the duty of removing the carcass of the dead camel, nothing to interrupt the routine of survey work occurred. The mates of the dead beast had evidently decided not to revisit their pasture grounds, for they did not put in a reappearance.
"Well, boys," said the professor one morning when they were all gathered at the summit of the mesa, "I guess that to-morrow morning we can say good-by to the scene of our rather tame adventures. My work is complete."
"How about the subterranean river?" asked Ralph, but a howl of derision from the others silenced him.
"Subterranean fiddlestick," burst out Jack, but the professor silenced him.
"The existence of such a stream is not so improbable as you seem to think," he said, "and Master Ralph is to be commended for his enterprising desire to locate it, but I think that our investigations have shown that if such a river ever did exist and the mesa dwellers had access to it, that the entrance, wherever it might have been, has vanished long ages ago."
Pete had taken no part in this conversation, but had wandered about the top of the mesa rather aimlessly, from time to time looking sharply at the surroundings beneath him in the alert manner of one whose life has been passed in the open places.
Suddenly he gave a quick exclamation and pointed off into the north-west.
"Look! Look there!" he exclaimed, riveting his eyes on something his keen vision had sighted, but which remained as yet invisible to the boys.
"What's coming—another storm?" asked Ralph.
"I don't know what it is yet," rejoined the other in a strangely uneasy tone, "it looks like—like——"
"A pillar of dust," exclaimed Jack, who had by this time sighted it, too, and had come to the aid of the unimaginative plainsman.
"So it does," cried the others, who now, with the exception of the short-sighted professor, could also see the approaching dust-cloud.
"What can it be?" wondered Walt, peering eagerly in its direction.
"Somebody riding. Several of 'em, I should say, by the dust they're raising," rejoined Pete bluntly.
The boys exchanged quick glances. Somebody riding across that arid waste? Their destination could only be the mesa, then, but who could it possibly be?
Had they been able to solve the riddle at that instant, they would have scattered pell-mell for their ponies, and made the best of their way from the Haunted Mesa, but, not being endowed with anything more than ordinary sensibilities, it was, of course, impossible for them to realize the deadly peril that was bearing down upon them in that dust-cloud.
"I can see things more clearly now," cried Jack, as for an instant a vagrant desert air blew aside the dust-cloud and revealed several riders, surrounding some cumbersome, moving object in their midst.
"There's a wagon!" he cried, "a big one, too, and surrounded by horsemen. What can it mean?"
"That we'd better be skedaddling as quick as possible," shot out Pete, brusquely.
The professor, who had wandered away from the group and was down inside the hollow altar, was hastily summoned and apprised of the strange approach of the mysterious cavalcade.
"Why, bless me, boys, what can it mean?" he cried, nimbly attempting a flying leap over the edge of the altar in his haste to ascertain for himself the nature of the approaching party.
Suddenly, however, as his feet touched the top, and he was scrambling over, he gave a sharp cry and fell back within the altar with a gasp of pain.
"Are you hurt?" asked Jack, running to the side of the ancient place of sacrifice.
The professor lay prostrate within. His face was white and set and beads of sweat stood out on his forehead.
"My—my ankle," he groaned. "I broke it some time ago, and in hurrying to clamber over the top of the altar I fear I have snapped it again. Oh!"
He gave a heartrending groan of pain. The boys stood stricken with consternation. It was going to be a long and difficult task to get the professor out of his present predicament, and there seemed need for haste.
"Here, put this under your head," said Jack, stripping off his jacket hastily, and throwing it within, "I'll tell Coyote Pete about your accident, and we can get remedies from the packs."
But when Jack turned, only Ralph and Walt stood beside him. The sturdy cow-puncher had vanished.
"He's gone to get the glasses," explained Walt.
Presently Coyote Pete, very much out of breath from his dash down the path and up again, stood beside them. He had the glasses in his hand, and lost no time in applying them to his eyes. He had not had them there two minutes when he gave a quick exclamation and turned hastily to the boys.
"Lie down; lie down, every one of you," he ordered sharply.
They lost no time in obeying, as they knew that the old plainsman must have an excellent reason for such a command. The next instant Pete himself followed their example. Crouching low, he once more peered through the glasses above the edge of the cup-like depression.
"Who are they?" asked Jack in a low voice, wriggling his way to Pete's side.
"I'm not sure yet, but they are all armed. I caught the flash of sunlight on their rifles. If they are Mexican insurrectos, we are in a bad fix."
"Mexicans! What would they be doing this side of the border?"
"That remains to be seen. But I don't like the looks of it."
"Suppose they are Mexicans, Pete, would they do us any harm?"
"That depends a whole lot on whether they are on lawful business or not."
"You mean——"
"That I don't like the looks of it. If there's an insurrection in Mexico, those fellows are after no good on this side of the border. They may be some band of cut-throats, who are taking advantage of the disturbances to raise Cain."
"Good gracious," exclaimed Jack, "and the professor's just injured himself so that we can't move him for some time anyhow."
Coyote Pete turned sharply on the boy.
"What's he done?"
"Broken his ankle, or, at any rate, seriously sprained it."
Pete's rejoinder to this was a long whistle of dismay. He said nothing, however, but once more applied the glasses to his eyes. Jack saw him gnaw his moustache, as he gazed out over the desert. The dust-cloud was quite close now—not more than a mile away. The boys, with their naked eyes, could easily catch the moving glint of metal.
"Well, Pete, what do you think?" inquired Jack eagerly, as the cowpuncher at length set down the glasses.
"That we're in Dutch," was the expressive rejoinder.