While Fremont was clambering down the eastern slope, studying the renegade Englishman whenever opportunity offered, and puzzling over the source of the fellow's information concerning the Cameron building and the Tolford estate papers, Ned Nestor and his companions were preparing to visit the interior of the strange shelter-place in which they found themselves.
The outer chamber, which, for convenience they marked "Chamber A"on the rough map they afterward made, was 30x40 feet in size, with the eastern side running parallel with the almost perpendicular face of rock which shot upward from the shelf which has before been alluded to. The opening faced directly east, and from it one could look miles over the desert of sand lying between the foot of the range and the Rio Grande del Norte, something like a hundred miles away.
To the north and south of this main chamber the boys found niches in the rock, evidently hewn there by man hundreds of years before.
The rock was very hard here, and it seemed that work had ceased for that reason.
On the west side of the chamber there were two openings, perhaps four feet by six, each leading into a chamber 20x30 feet in size.
Before entering these rooms, which held an odor of dampness and decay, the recently arrived Black Bears produced electric flashlights.
"We looked up Old Mexico," Harry Stevens said, turning on the flame, "and knew we'd be nosing around in caves and tunnels before we got back to God's country, so we brought our glims along with us.""Well, don't burn them all at once," advised Nestor. "We shall need them for several days, probably, and there are no shops in the next block where dry batteries can be bought. Leave one out and put the rest away.""We have a few extra batteries," said Harry. "We looked out for that.""We shall doubtless need all you have, no matter how economically they are used," Nestor said. "Let me take the one you have, and I'll go on an exploring expedition into the south chamber.""Me for the exploring expedition too!" cried Harry. "I want to see how it seems to go into a room ten thousand years old.""Nixt ten thousand years!" observed Jimmie.
Harry nudged Peter Fenton and pointed to the west wall of the chamber, across which he threw the brilliant circle of the flashlight.
"There is the record," he said.
"Nix ten thousand years old!" insisted Jimmie.
No one knows how old," Fenton said. "No one has ever been able to translate the picture talk of the very early inhabitants.
The man who carved those lines might have existed when the sandy desert out there was under water.""Speaking of water, let's go on and see where they got their drinkings," put in Frank Shaw. "I'm nearly choked, and I'll bet there's a spring about here somewhere.""Any old time you don't want something to eat or drink!" laughed Harry. "Well," he added, handing the flashlight to Nestor, "we may as well go in and see if there is a water system here.""There surely is," Fenton said. "The people who dug this shelter out did not work where there was no water. If Nature did not supply it, they built aqueducts to convey it to locations where it was wanted. But Professor Agassiz says they lived ten thousand years ago, so, if they did put in a water system here, it may be out of commission now.""How does he know how long ago they lived?" asked Jack.
"By their bones," was the reply. "Near New Orleans, under four successive forests, one on top of the other, and each showing traces of having been occupied by man, explorers recently discovered a human skeleton estimated to be fifty thousand years old. That fellow must have lived just after the last glacial epoch.""I don't believe they know anything about how long ago he lived,"observed Jimmie. "How can any one tell how long ago the last glacial epoch closed?""Figure out how far the melting line traveled from south to north,"said Fenton, "then figure that the glaciers receded at the rate of only twelve feet every hundred years, and you'll know something about it.""Come on!" cried Frank, "let's get in there and find their Croton system. I'm so thirsty my throat sizzles. Come on!"Nestor, closely followed by the others, led the way into the south chamber, called, for convenience, "Chamber B" on the rough map made later on. The place was damp and cold, and a current of air came from the southwest corner, indicating an opening there.
After clearing away a heap of rocks and loose sand, which might once have been rock, the boys found an opening which had been, apparently, closed for a long period of time. When finally cleared, after an hour of hard work, the opening from which the current of air had come was discovered to be a door like arch in the west wall of the main chamber.
The electric flashlight, however, when introduced into the opening, showed a narrow passage beyond the opening instead of a square room. This tunnel-like passage was not far from six feet in width and about that in height. The walls showed that it had been cut through solid rock.
The boys listened for some indication of life or motion in the tunnel, but all was silent. Not even a bird or creeping thing disturbed the stillness of the place.
"Shall we go in now?" asked Nestor.
"Sure!" replied Shaw. "We may find a well in there!""Or a soda fountain, or a modern filter," grinned Jimmie.
