Page:Quarterly Journal of the Geological Society of London, vol. 27.djvu/177

 are everywhere of very limited extent and thickness, and the so- called " reefs " everywhere thin out rapidly towards the base ; and, lastly, there is no extensive alluvium anywhere in these districts which yields gold.

It is a well-known fact that gold has actually been exported from the east coast for centuries by the Portuguese in large amounts ; and the question may be put, Whence does this gold come ? Gold is there ; but the question is, Would it pay white labour or not ? The Portuguese trader in Quillimane has perhaps one thousand or more slaves, which cost him only a trifle, as they live by their wives' labour ; when the dry season sets in, the Quillimane traders send their slaves to their work ; they are supplied with old flint-guns, and sent into the interior to hunt elephants. Some are sent to trade, and a great part to the diggings in the rivers which flow into the Zambezi, near Tette, and in those running from the south to the Zambezi, coming from the fabulous country of Manico. There the wives work at fields of rice, which support them sufficiently, whilst the men wash the gold from the rivers in small kalabashes in quite a primitive manner. As the gold itself has no value to them, they bring it faithfully to their masters, who reward them with beads and white Salempore (calico). In this way the master gains a good deal, as all the gold he receives is a clear profit. If he has only 150 slaves engaged in the diggings, and he receives only 1 ounce per head in the season, he makes a profit of <£581 5s. ! Of course white labourers would never find it practicable to undertake gold- washing there under such circumstances.

b. Copper is already well known in many districts of South Africa, and is also worked. I found copper at several localities in Natal ; but nowhere, I should think, would it be found practicable to work it. Near the Ifumi river, south of Durban, a highly decomposed gneiss occurs which shows traces of copper at the surface. It is situated just along a fissure in the gneiss, and it possibly might lead to a richer point ; but this is not probable. In the Insiswa Mountains, in Kaffirland, richer copper-ores have been known for a very long time, but have never been worked out. This locality is situated at the above- mentioned line of greenstone, which strikes from south to north, near the base of the Karoo beds. It is remarkable that along this greenstone line copper is found. Thus, for instance, it occurs near the Tugela valley, in greenstone which intersects the granite.

EXPLANATION OF PLATES II. & III.

Plate II.

Geological Map of the Colony of Natal.

Section from the Bluff, Port Natal, to the Mont aux Sources in the Draakensberg.

Plate III.

Fig. 1. Ammonites umbolazi, Baily : a, dorsal view ; b, sutures.

Fig. 2. Ammonites rembda, Forbes ; a, section ; b, sutures.

Fig. 3. The same, young individual.

Fig. 4. Anisoceras rugatum, Forbes.