"It's a mesa," replied Ned with renewed enthusiasm, "and it will be a good thing to look over it to-morrow. These high and almost unapproachable islands of rock were favorite dwelling places for the Indians."
"But a temple up here wouldn't be a secret very long," replied Alan. "We've seen this point all afternoon. It's prominent enough."
"That's so," answered Ned, "but we are here, so let's make a landing and eat, and dream over it."
The balloon had now lost so much gas that a landing was easy, and, tired with four days' profitless search and its strain, the young aeronauts were soon beyond even dreams.
It was with no small alarm that the boys saw, when they awoke with the first rays of the sun, that the car of the Cibola, which had been anchored fore and aft to heaped up rocks during the night, was now resting on the ground. Gas, was rapidly escaping. But fortunately the aeroplanes and propeller had been left properly in a horizontal position and no damage had been done.
The boys knew that by throwing over enough ballast and stores the Cibola could be made good for one more flight, but that probably it would be the last. Therefore, the inevitable seemed forced upon them. They would fortify themselves with a good breakfast, look over the mesa, make one more circling flight and then attempt to find Camp Eagle. While Alan made haste to prepare breakfast, Ned determined first on an examination of the mesa point by daylight.
The rock had a top area of perhaps forty or fifty acres. It had a rolling surface and was coated with a carpet of dusty sand, except in the northwest corner. The northern end of the mesa, Ned could see, widened and ended in a sharp rise almost wall-like in form. At the western end this wall-like elevation turned the corner and extended south a short distance, finally dropping down to the general level of the mesa. In this protected comer grew a strange grove of gnarled and twisted pines, ill nourished and apparently very old. Between this comer of the mesa and the sharper promontory whereon the Cibola had come to anchor, was a wide, sandy, barren depression.
The narrow portion of the rocky island where the boys had made camp drew in abruptly to make the point that marked the southern end of the mesa. Ned turned first toward the point.
When he had advanced, making his way slightly upward all the time, to where the narrow mesa was not over four hundred feet wide, the lad was astounded to suddenly discover a deep and narrow fissure or chasm. It was dark, with sides as abrupt as the cliffs of the mesa, and too wide to jump across. A cold air was already rising from the opening into the warmer atmosphere above.
In his astonishment Ned called to his chum.