own
gulfs of time. He forced his mind to heel. "It means there are people
here in this time," he said huskily. "People, or _something_, who know
how to make planes."

Michaelson nodded. "That would be my conclusion," he said.

"But that is impossible," Higgins flared. "If there had been
civilizations in the past, we would have a record of them. I mean, we
would have found their cities, even if the people had disappeared. We
would have found traces of their factories, of their buildings--"

"Would we?" Michaelson asked.

"Certainly. Don't you agree with me?"

"Not necessarily," the scientist said. "You are forgetting one important
fact--the size of a million years. A million years from now will anyone
be able to find New York? Chicago? London? The steel mills of
Pittsburgh? I think not. In that length of time, the action of the rain,
the frost, and the sun will have completely destroyed every sign that
these places once existed. Besides, the continents we now know may have
sunk and new ones appeared. How could we locate the ruin of Pittsburgh
if the city were at the bottom of the Atlantic? A million years ago
there may have been huge cities on earth. Man is not necessarily the
first race ever to appear on the planet."

Craig, listening, recognized the logic in what Michaelson had said.
There might have been other races on earth! The vanity of men blinded
them to that fact, when they thought about it at all. They wanted to
believe they were the most important, and the only effort of creation,
that the earth had come into being expressly for their benefit. Nature
might have other plans.

Michaelson had suggested a logical solution for the dilemma of airplanes
and flying dragons existing in the same world.

Craig saw the officers glancing uneasily in the direction from which the
planes had come. Off yonder somewhere below the horizon was _something_.
They were worried about it. Against the beasts of this time, the Idaho
was all-powerful. But how would the Idaho stack up against the
_something_ that lay below the horizon? Or would the ship be able to
escape back through the time fault before the threat of the mysterious
planes became greater?

Out around the ship, small boats were planting charges of explosive. One
boat was dashing out to the wrecked scouting plane to rescue the pilot.

"We have to see if we can get away from here, at once," Higgins said.
"We have to set off those explosives and see if they will