rry. "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