there is
rain, and that it is merely in transit, and so affects only the bed on
which it moves. Granting that this is the eastern of the two
continents we observed, it evidently corresponds more in shape to the
Eastern hemisphere on earth than to the New World, both of which are
set facing one another, since both drain towards the Atlantic Ocean.
But the analogy here holds also, for the past outlines of the Eastern
hemisphere differed radically from what they are now. The
Mediterranean Sea was formerly of far greater extent than we see it
to-day, and covered nearly the whole of northern Africa and the old
upheaved sea-bottom that we see in the Desert of Sahara. Much of this
great desert, as we know, has a considerable elevation, though part of
it is still below the level of the Mediterranean.

"Perhaps a more striking proof of this than are the remains of fishes
and marine life that are found there, is the dearth of natural harbours
and indentations in Africa's northern coast, while just opposite, in
southern Europe, there are any number; which shows that not enough time
has elapsed since Africa's upheaval for liquid or congealed water to
produce them. Many of Europe's best harbours, and Boston's, in our
country, have been dug out by slow ice-action in the oft-recurring
Glacial periods. The Black and Caspian Seas were larger than we now
find them; while the Adriatic extended much farther into the continent,
covering most of the country now in the valley of the Po. In Europe
the land has, of course, risen also, but so slowly that the rivers have
been able to keep their channels cut down; proof of their ability to
perform which feat we see when an ancient river passes through a ridge
of hills or mountains. The river had doubtless been there long before
the mountains began to rise, but their elevation was so gradual that
the rate of the river's cutting down equalled or exceeded their coming
up; proof of which we have in the patent fact that the ancient river's
course remains unchanged, and is at right angles to the mountain chain.
From all of which we see that the Eastern hemisphere's crescent
hollow--of which, I take it, the Mediterranean, Black, and Caspian Sea
depressions are the remains--has been gradually filled in, by the
elevation of the sea's bottom, and the extension of deltas from the
detrital matter brought from the high interior of the continents by the
rivers, or by the combined action of the two. Now