the bluffs with their geometric lines, formed oftener of palisades
than walls. There were few villages, and few inhabitants, the country
differing widely from the auriferous lands of Colorado many leagues
to the south.

In the distance a long line of mountain crests, in great confusion as
yet, began to appear. They were the Rocky Mountains.

For the first time that morning Uncle Prudent and Phil Evans were
sensible of a certain lowness of temperature which was not due to a
change in the weather, for the sun shone in superb splendor.

"It is because of the "Albatross" being higher in the air," said Phil
Evans.

In fact the barometer outside the central deck-house had fallen 540
millimeters, thus indicating an elevation of about 10,000 feet above
the sea. The aeronef was at this altitude owing to the elevation of
the ground. An hour before she had been at a height of 13,000 feet,
and behind her were mountains covered with perpetual snow.

There was nothing Uncle Prudent and his companion could remember
which would lead them to discover where they were. During the night
the "Albatross" had made several stretches north and south at
tremendous speed, and that was what had put them out of their
reckoning.

After talking over several hypotheses more or less plausible they
came to the conclusion that this country encircled with mountains
must be the district declared by an Act of Congress in March, 1872,