Judging, Indeed, From All The Evidences As Yet Collected, The Interior Of South Africa Has Remained In That Condition Since The Period Of The Secondary Rocks Of Geologists!

Yet, whilst none of our countrymen found any evidences of old marine remains, Captain Speke brought from one of the ridges which lay between the coast and the lake Victoria N'yanza a fossil shell, which, though larger in size, is undistinguishable from the Achatina perdix now flourishing in South Africa.

Again, whilst Bain found fossil plants in his reptiliferous strata north of the Cape, and Livingstone and Thornton discovered coal in sandstone, with fossil plants, like those of our old coal of Europe and America, - yet both these mesozoic and palaeozoic remains are terrestrial, and are not associated with marine limestones, indicative of those oscillations of the land which are so common in other countries.

"It is further to be observed, that the surface of this vast interior is entirely exempt from the coarse superficial drift that encumbers so many countries, as derived from lofty mountain-chains from which either glaciers or great torrential streams have descended. In this respect, it is also equally unlike those plains of Germany, Poland, and Northern Russia, which were sea-bottoms when floating icebergs melted and dropped the loads of stone which they were transporting from Scandinavia and Lapland.

"In truth, therefore, the inner portion of Southern Africa is, in this respect, as far as I know, geologically unique in the long conservation of ancient terrestrial conditions. This inference is further supported by the concomitant absence, throughout the larger portion of all this vast area, i.e. south of the Equator, of any of those volcanic rocks which are so often associated with oscillations of the terra firma ["Although Kilimandjaro is to a great extent igneous and volcanic, there is nothing to prove it has been in activity during the historic era."]

"With the exception of the true volcanic hills of the Cameroons recently described by Burton, on the west coast, a little to the north of the Equator, and which possibly may advance southwards towards the Gaboon country, nothing is known of the presence of any similar foci of sub-aerial eruption all round the coasts of Africa south of the Equator. If the elements for the production of them had existed, the coast-line is precisely that on which we should expect to find such volcanic vents, if we judge by the analogy of all volcanic regions where the habitual igneous eruptions are not distant from the sea, or from great internal masses of water. The absence, then, both on the coasts and in the interior, of any eruptive rocks which can have been thrown up under the atmosphere since the period when the tertiary rocks began to be accumulated, is in concurrence with all the physical data as yet got together. These demonstrate that, although the geologist finds here none of those characters of lithological structure and curiously diversified organic remains which enable him to fix the epochs of succession in the crust of the earth in other quarters of the globe, the interior of South Africa is unquestionably a grand type of a region which has preserved its ancient terrestrial conditions during a very long period, unaffected by any changes except those which are dependent on atmospheric and meteoric influences.

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