erable altitudes in the east. The tops of all
glistened with a mantle of snow in the sunlight, while between the
ridges they saw darker and evidently fertile valleys. They passed,
moving northwest, over large and small lakes, all evidently part of the
same great system, and continued to sweep along for several days with a
beautiful panorama, as varying as a kaleidoscope, spread beneath their
eyes. They observed that the character of the country gradually
changed. The symmetrically rounded mountains and hills began to show
angles, while great slabs of rock were split from the faces. The sides
also became less vertical, and there was an accumulation of detrital
fragments about their bases. These heaps of fractured stone had in
some cases begun to disintegrate and form soil, on which there was a
scant growth of vegetation; but the sides and summits, whose jaggedness
increased with their height, were absolutely bare.

"Here," said Cortlandt, "we have unmistakable evidence of frost and ice
action. The next interesting question is, How recently has denudation
occurred? The absence of plant life at the exposed places," he
continued, as if lecturing to a class, "can be accounted for here, as
nearer the equator, by the violence of the wind; but I greatly doubt
whether water will now freeze in this latitude at any season of the
year, for, even should the Northern hemisphere's very insignificant
winter coincide with the planet's aphelion, the necessary drop from the
present temperature would be too great to be at all probable. If,
then, it is granted that ice does not form here now, notwithstanding
the fact that it has done so, the most plausible conclusion is that the
inclination of Jupiter's axis is automatically changing, as we know the
earth's has often done. There being nothing incompatible in this view
with the evidence at hand, we can safely assume it correct for the time
being at least. When farther south, you remember, we found no trace of
ice action, notwithstanding the comparative slowness with which we
decided that the ridges in the crust had been upheaved on account of
the resisting power of gravity, and, as I see now, also on account of
Jupiter's great mass, which must prevent its losing its heat anything
like as fast as the earth has, in which I think also we have the
explanation of the comparatively low elevation of the mountains that we
found we could not account for by the power of gravitation alone.[2]