from
its great hardness and toughness, and from its great weight. The origin
of these dykes is well known. They have been produced by volcanic
agency, which, acting from below upon horizontal beds of stratified
rock, has cracked and fissured them at right angles to their planes of
stratification, and these vertical cracks have been filled up with the
melted rock or the lava from below. The perpendicular fissures through
which it has found its way upwards are seldom seen, nor should we
expect to see much of them, for it is precisely along the line of these
that the rocks have been most broken up and shattered and the
denudation has been greatest."
Even
in the crossing of the karroos there were curious and awesome sights to
attract and impress the mind of a traveller beholding for the first
time these desert wastes so widely spread over the face of South
Africa. They differ little in appearance except in size. The Great or
Central Karroo, which lies beneath the foot-hills of the Zwarte Bergen
range, has a sweep to the north of more than three hundred miles in a
rolling plateau, ranging in elevation from two to three thousand feet.
Day after day, as the diamond seekers from Cape Town plodded on with
their creaking wagons, the same purpled brown face was outspread before
them of the stunted flowering shrub which has given its name to the
desert, spotted with patches of sun-cracked clay or hot red sand. To
some of the Scotchmen this scrub had the cheery face of the heather of
their own Highlands, and homesick Englishmen would ramble far through
the furze to pick the bright yellow flowers of plants that recalled the
gorse of their island homes.1 These common bushes, rarely
rising a foot in height, and the thick, stunted camelthorn, were almost
the only vegetable coating of the desert.
Straggling
over this plane ran the quaint ranges of flat-topped hummocks and
pointed spitz-kopjes, streaked with ragged ravines torn by the floods,
but utterly parched for most of the year. Shy meerkats, Cynictis penicillata, weasel-like crea-
1 Special correspondence London Chronicle and other English journals, November, 1899.
