," replied Griggs; "fair play's a jewel. Let's go back; your father
will like to be one of the first to begin exploring."

"So he will; but look, here they come."

For Ned was close up, being the next to test the stability of the new
ladder, and was closely followed by the doctor and their other friends.

"Capital!" cried the doctor. "A much finer view from up here. Why,
with such a stronghold and no better way for the enemy to approach, the
old people ought to have been able to set all the tribes of the plain at
defiance."

"Perhaps they did, sir," said Griggs; "but it seems to me that they must
have had a regular channel of water coming down from above there to
supply all these rooms, or cells, as you call them."

"Most likely," said the doctor.

"How would it be then if the enemy managed to break down the channel
from somewhere up yonder where we found the hole under the fallen
stones? Could the people who attacked them have done that?"

"Why, Griggs, you are making history. That was the old people's
aqueduct, and it is quite possible that when they were besieged the
enemy caused the destruction over which we climbed."

"Yes," said Griggs thoughtfully; "that would ruin the folk. No doubt
some of these places were used as stores, and those might last for
years; but if their supply of water were cut off there wouldn't be much
chance for them then."

"Well, let's see farther," said the doctor. "I can't help thinking that
they must have been a strong and fairly civilised race."

Chris led the way in, to find the cell he entered cut out and built-up
just the same as those which they had seen; but the floor was encumbered
deeply with the dust of ages, and on stirring some of it with his foot
the boy drew back hurriedly and looked strangely at his father.

"What have you found?" said the doctor.

"The jaguars must have killed a man here, father," replied the boy, who
looked on in disgust as his father stepped in and picked up a skull
which might have lain there, sheltered by the roofing of stone, for
ages. It looked brown and as if very little pressure would suffice to
crumble it up into dust; but the teeth left in the upper jaw were
perfect and fairly white.

"Ah!" said the doctor thoughtfully. "Here's a bit of genuine history at
last."

"Killed by a jaguar, father?" cried Chris excitedly.

"No, my boy," was the reply; "this is not the marking of a jaguar's
teeth, but the cause of death, plainly