eason to doubt the native testimony. The distance
between Dilolo and the valleys leading to that of the Kasai is not more
than fifteen miles, and the plains between are perfectly level; and, had
I returned, I should only have found that this little lake Dilolo, by
giving a portion to the Kasai and another to the Zambesi, distributes
its waters to the Atlantic and Indian Oceans. I state the fact exactly
as it opened to my own mind, for it was only now that I apprehended the
true form of the river systems and continent. I had seen the various
rivers of this country on the western side flowing from the subtending
ridges into the centre, and had received information from natives and
Arabs that most of the rivers on the eastern side of the same great
region took a somewhat similar course from an elevated ridge there, and
that all united in two main drains, the one flowing to the north and the
other to the south, and that the northern drain found its way out by the
Congo to the west, and the southern by the Zambesi to the east. I was
thus on the watershed, or highest point of these two great systems, but
still not more than 4000 feet above the level of the sea, and 1000 feet
lower than the top of the western ridge we had already crossed; yet,
instead of lofty snow-clad mountains appearing to verify the conjectures
of the speculative, we had extensive plains, over which one may travel a
month without seeing any thing higher than an ant-hill or a tree. I was
not then aware that any one else had discovered the elevated trough form
of the centre of Africa.

I had observed that the old schistose rocks on the sides dipped in
toward the centre of the country, and their strike nearly corresponded
with the major axis of the continent; and also that where the later
erupted trap rocks had been spread out in tabular masses over the
central plateau, they had borne angular fragments of the older rocks in
their substance; but the partial generalization which the observations
led to was, that great volcanic action had taken place in ancient times,
somewhat in the same way it does now, at distances of not more than
three hundred miles from the sea, and that this igneous action,
extending along both sides of the continent, had tilted up the lateral
rocks in the manner they are now seen to lie. The greater energy and
more extended range of igneous action in those very remote periods when
Africa was formed, embracing all the flanks, imparted to i