nd, "that the present North Polar regions were tropical in
temperature and in animal and vegetable life, a long time ago."

"Yes, they find there, skeletons of animals which now exist only in the
tropics," said Jimmie, "and tropical trees deep under the ice. The
earth, they say, shifted in its orbit and it grew cold up there. I
guess that is why we read of people always coming down from the North."

"They had to get out of the North," the drummer mused, "because during
the Glacial period an ice-cap miles in thickness covered the world down
as far as the dividing line between the British possessions and the
United States. That is the way California and Mexico and Central
America were populated, anyhow."

"You mean that the immediate ancestors of the people of those countries
came from the North," Jimmie criticized. "For all we know, the people
who lived before them came from the South. They left no records to
show that they ever existed, but the earth was not bare of animal life
back of the period our scientists figure from."

"The first ones came from the East, by way of Iceland, Greenland, and
Baffinland; from the Eastern continent, and about the vicinity of the
Caspian sea, and so kept on South on this continent as the climate grew
colder. But we were talking of the people of Mexico. I wanted to show
you that they have never been favored as the people of our country
have, and that they've got years of national childhood to go through
yet before they become a great people."

"Go on and tell me about it," urged Jimmie. "We may learn as much
about what's going on here by sitting on this plateau as we could by
climbing our heads off."

The boys listened a moment, but there were no suspicious sounds about.
The mountain lay as silent under the moon as if no human foot had ever
pressed its surface. There were lights far down in the valley, but
none on the slopes in view.

"About as far back as the books go in Mexican history," the drummer
began, "is the seventh century, even when England wasn't much. About
that time the Toltecs came out of the North and took possession of the
valley where the City of Mexico now is. They were industrious,
peaceful and skilled in many of the arts. They kept their records in
hieroglyphics.

"They had a year made up of eighteen months of twenty days each, the
other five and a fraction being chucked into the calendar any old way.
They knew about the stars and eclipses, and buil