"It's the overflow from them old-timers' well at the base of the mesa,"

p.r.o.nounced Pete, listening.

"Yes, and here it is," cried Jack, who had been riding a short distance in advance, and had suddenly come across a small stream.

The water was but a tiny thread, but it looked as welcome just then as a whole lake. Cautioning the boys to keep their ponies back, Pete took a long-handled shovel from one of the packs, and soon excavated quite a little basin. While he had been doing this, the boys had had to restrain their thirst, for the ponies were almost crazy with impatience to get at the water. It required all the boys' management, in fact, to keep them from breaking away and getting at the water. In the heated condition of the little animals, this might have meant a case of foundering. At last Pete let the thirsty creatures take a little water, and afterward they were tethered to a clump of brush, while the boys themselves a.s.suaged their pangs. After their first ravenous thirst was quenched--which was not soon--they took turns in dashing water over each other's heads, removing the last traces of the sand-storm. This done, they all declared that they felt like new men,--or boys,--and a unanimous cry for supper arose.

"Let me see, now," mused Pete, gazing up at the purplish, black heights of the mesa above them, "as I recollect it, there's only one path up thar. The good book says, foller the strait and narrer path, but it don't say nothing about doing it in the dark, so I reckon that the best thing we can do will be to camp right under that bluff thar, whar the water comes out, till it gets to be daylight."

This was agreed to be an excellent plan, and, accordingly, the stock having been tethered out amidst the bunch-gra.s.s, the packs were unloaded, and the work of getting a camp in shape proceeded apace. In that part of New Mexico, although it is warm enough by day, nightfall brings with it a sharp chill. It was decided, therefore, to rig up the tents and sleep under their protection. The three canvas shelters of the bell type were soon erected, and then, with mesquite roots, Coyote Pete kindled a fire and put the kettle on. Supper consisted of corned beef, canned corn and canned tomatoes, with coffee, hard biscuit and cheese.

"I'll bet we're the first folks that have eaten a meal here for many a long day," said Jack, looking about him, after his hunger had been satisfied.

"It is, in all probability, fifteen hundred years or more since the first inhabitants of this mesa dwelt here," announced the professor.

"My! My! You could boil an egg in that time," commented Pete, drawing out his old black briar and lighting it. He lay on one elbow and began to smoke contemplatively.

The others did not speak for a few moments, so engrossed were they with the ideas that the professor had summoned up. Once, perhaps, this dead, black, empty mesa above them had held busy, bustling life. Now it stood silently brooding amid the desolation stretched about it, as solitary as the Sphinx itself.

The spot at which they were camped was the sheer, or cliff side of the mesa. At the other side they knew, from Coyote Pete's description, were numerous openings and a zig-zag pathway leading up to the very summit. It was on this summit, which according to the most accurate information obtainable had once been used for the sacrificial rites of sun worship, that the professor expected to find the relics for which he was searching.

For an hour or two the lads discussed the dead-and-gone mesa dwellers, with an occasional word from the professor, who was deeply read on the subject. This was all so much Greek to Pete, who solemnly smoked away, every now and then putting in a word or two, but for the most part lying in silence, looking out beyond the black shadow of the mesa across the moonlit desert toward the rocky hills to the south.

Suddenly, the lanky cowboy leaped to his feet with a yell that punctured the silence like a pistol-shot. In two flying leaps, he had bounded clear over the professor's head, and was in among the tents, searching for his pistol. Before one of the amazed group about the fire could collect his senses at the sudden galvanizing of Coyote Pete, he was back among them again.

"Wow!" he yelled into the night, "come on, there, you, whoever you are!

Come on, I say! I'll give you a fight! Yep, big as you are, I ain't skeered of you."

"Pete! Pete! Whatever is the matter?" gasped Jack, who, with the others, was by this time on his feet.

"Matter?" howled Pete. "Matter enough. I do begin to think this place sh.o.r.e is haunted, or suthin'. As I lay there, I felt suthin' tiptoeing about behind me, and when I whipped suddenly round ter see if one of the critters hadn't broken loose, what did I see but a great, big, enormous thing, as big as a house, looking down at me. Afore I could say a word, it was gone."

"Gone!" echoed the others. "What was it?"

"Wish you'd tell me," sputtered the cow-puncher, looking about him, and still gripping his gun, "I never saw the like in all my born days."

"Well, what did it look like?"

"Hard to tell you," rejoined Pete. "It was as big as that." He pointed right up at the moon.

"As tall as the moon? Oh, come, Pete, you had dropped off and were dreaming," laughed Ralph.

"Who said it was as tall as the moon?" demanded the excited cow-puncher angrily. "I only meant to convey to your benighted senses some idee uv what it luked like."

"Well, how high was it?" asked Jack, in whose tones was a curious note of interest, for a reason we can guess.

"About twenty feet, as near's I could judge. It had red eyes, that glared like the tail-lamps of a train, and it spat fire, and it----"

"Whoa! Whoa!" laughed Walt Phelps. "Now we know it was a nightmare, Pete. The dream of a rarebit fiend. You ate too much crackers and cheese at supper."

"How was it we didn't see it?" asked Ralph, who had not spoken up till now.

"Why, you were lying with your back toward the direction it came from,"

explained Pete.

"An interesting optical delusion," declared the professor. "I must make a note of it, and----"

"Wow! There it goes ag'in."

"Where? Where?" chorused the boys.

"Right off there! Look! Look!"

The lanky cow-puncher, fairly dancing about with excitement, pointed out beyond the shadow of the solitary mesa. Sure enough, there were three or four enormous, black, shadowy shapes, traveling across the sands at a seemingly great speed.

"Get your rifles, boys!" yelled Jack.

The weapons lay handy, and in a jiffy four beads had been drawn on the immense, vague shapes.

But even as their fingers pressed the triggers, and the four reports rang out as one, the indefinite forms vanished as mysteriously as they had appeared.

CHAPTER IV.

SOME QUEER TRACKS.

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 bunchgra.s.s, 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.