ceptical, because the large footstep of the
first man Matsieng was directed as if going into instead of out of this
famous pot-hole. Other huge pot-holes are met with all over the country,
and at heights on the slopes of the mountains far above the levels of
the ancient rivers.

Many fountains rose in the courses of the ancient river beds, and the
outflow was always in the direction of the current of the parent stream.
Many of these ancient fountains still contain water, and form the stages
on a journey, but the primitive waters seem generally to have been laden
with lime in solution: this lime was deposited in vast lakes, which are
now covered with calcareous tufa. One enormous fresh-water lake, in
which probably sported the Dyconodon, was let off when the remarkable
rent was made in the basalt which now constitutes the Victoria Falls.
Another seems to have gone to the sea when a similar fissure was made at
the falls of the Orange River. It is in this calcareous tufa alone that
fossil animal remains have yet been found. There are no marine
limestones except in friths which the elevation of the west and east
coasts have placed far inland in the Coanza and Somauli country, and
these contain the same shells as now live in the adjacent seas.

Antecedently to the river system, which seems to have been a great
southern Nile flowing from the sources of the Zambesi away south to the
Orange River, there existed a state of fluvial action of greater
activity than any we see now: it produced prodigious beds of
well-rounded shingle and gravel. It is impossible to form an idea of
their extent. The Loangwa flows through the bed of an ancient lake,
whose banks are sixty feet thick, of well-rounded shingle. The Zambesi
flows above the Kebrabasa, through great beds of the same formation, and
generally they are of hard crystalline rocks; and it is impossible to
conjecture what the condition of the country was when the large
pot-holes were formed up the hillsides, and the prodigious attrition
that rounded the shingle was going on. The land does not seem to have
been submerged, because marine limestones (save in the exceptional cases
noted) are wanting; and torrents cutting across the ancient river beds
reveal fresh-water shells identical with those that now inhabit its
fresh waters. The calcareous tufa seems to be the most recent rock
formed. At the point of junction of the great southern prehistoric Nile
with an ancient fresh-water lake