Africa

Land. In each country the same succession of the rocks is met with; over

both the same specialized orders of reptiles roamed and were entombed.

The interior of the African portion of Gondwana Land was occupied by

several large lakes in which an immense thickness—amounting to over 18,000

ft. in South Africa—-of sandstones and marls, forming the Karroo system,

was laid down. This is par excellence the African formation, and covers

immense areas in South Africa and the Congo basin, with detached portions

in East Africa. During the whole of the time—-Carboniferous to Rhaetic—that

this great accumulation of freshwater beds was taking place, the interior

of the continent must have been undergoing depression. The commencement of

the period was marked by one of the most wonderful episodes in the

geological history of Africa. Preserved in the formation known as the Dwyka

Conglomerate, are evidences that at this time the greater portion of South

Africa was undergoing extreme glaciation, while the same conditions appear

to have prevailed in India

TABLE OF FORMATIONS

Sedimentary. Igneous.

Recent Alluvium; travertine;

coral; sand dunes; continental } Some volcanic

islands;

dunes. Generally distributed } rift-valley

volcanoes.

Pleistocene. Ancient alluviums and }

gravels; travertine. }

Generally distributed. } A long-continued

Pliocene. N. Africa; Madagascar. } succession in the

} central and

northern

Miocene. N. Africa. } regions and among

} the island

groups.

Oligocene. N. Africa. } Doubtfully represented

} south of the

Zambezi.

Eocene. N. Africa, along east and }

west coasts; Madagascar. }

Cretaceous Extensively developed in } Diamond pipes of S.

N. Africa; along coast } Africa; Kaptian

and foot-plateaus in east } fissure

eruptions;

and west; Madagascar. } Ashangi traps of

} Abyssinia

{Jurassic N. Africa; E. Africa;

K{ Madagascar; Stormberg } Chief volcanic

period

a{ period (Rhaeric) in S. } in S. Africa

r{ Africa }

r{Trias. Beaufort Series in S. }

o{ Africa; Congo basin; }

o{ Central Africa; Algeria; }

{ Tunis. }

{Permian. Ecca Series in S. Africa. } Feebly, if anywhere

} developed.

Carboniferous. N. Africa; Sabaki Shales }

in E. Africa; Dwyka }

and Wittebery Series in }

South Africa }

Devonian. N. Africa; Angola; Bokkeveld } Not recorded.

Series in S. Africa }

Silurian. {Table Mountain Sandstone }

{ in S. Africa, Silurian(?). }

Ordovician. { Doubtfully represented } Klipriversberg and

{ in N. Africa, French } and Ventersdorp

Series

Cambrian { Congo, Angola. and by } of the Transvaal (?).

{ Vaal River and Waterberg }

{ Series in S. Africa }

Pre-Cambrian. Quartzites, conglomerates }

phyllites, jasper-bearing } S. Africa and

generally.

rocks and schists. }

Generally distributed. }

Archeaan. Gneisses and schists of the } Igneous complex of

continental platform. } sheared igneous

} rocks;granites.

and Australia. At the close of the Karroo period there was a remarkable

manifestation of volcanic activity which again has its parallel in the

Deccan traps of India.

How far the Karroo formation extended beyond its present confines has not

been determined. To the east it reached India. In the south all that can be

said is that it extended to the south of Worcester in Cape Colony. The

Crystal Mountains of Angola may represent its western boundary; while the

absence of mesozoic strata beneath the Cretaceous rocks of the mid-Sahara

indicates that the system of Karroo lakeland had here reached its most

northerly extension. Towards the close of the Karroo period, possibly about

the middle, the southern rim of the great central depression became ridged

up to form the folded regions of the Zwaarteberg, Cedarberg and Langeberg

mountains in Cape Colony. This folded belt gives Africa its abrupt southern

termination, and may be regarded as an embryonic indication of its present

outline. The exact date of the maximum development of this folding is

unknown, but it had done its work and some 10,000 ft. of strata had been

removed before the commencement of the Cretaceous period. It appears to

approximate in time to the similar earth movement and denudation at the

close of the palaeozoic period in Europe. It was doubtless connected with

the disruption of Gondwana Land, since it is known that this great

alteration of geographical outline commenced in Jurassic times.

The breaking up of Gondwana Land is usually considered to have been

caused by a series of blocks of country being let down by faulting with the

consequent formation of the Indian Ocean. Other blocks, termed horsts,

remained unmoved, the island of Madagascar affording a striking example. In

the African portion Ruwenzori is regarded by some geologists to be a block

mountain or horst.

In Jurassic times 1he sea gained access to East Africa north of

Mozambique, but does not appear to have reached far beyond the foot-plateau

except in Abyssinia.

The Cretaceous seas appear to have extended into the central Saharan

regions, for fossils of this age have been discovered in the interior. On

the west coast Cretaceous rocks extend continuously from Mogador to Cape

Blanco. From here they are absent up to the Gabun river, where they

commence to form a narrow fringe as far as the Kunene river, though often

overlain by recent deposits. They are again absent up to the Sunday river

in Cape Colony, where Lower Cretaceous rocks (for long considered to be of

Oolitic age) of an inshore character are met with. Strata of Upper

Cretaceous age occur in Pondoland and Natal, and are of exceptional

interest since the fossils show an intermingling of Pacific types with

other forms having European affinities. In Mozambique and in German East

Africa, Cretaceous rocks extend from the coast to a distance inland of over

100 m.

Except in northern Africa, the Tertiary formations only occur in a few

isolated patches on the east and west coasts. In northern Africa they are

well developed and of much interest. They contain the well-known nummulitic

limestone of Eocene age, which has been traced from Egypt across Asia to

China. The Upper Eocene rocks of Egypt have also yielded primeval types of

the Proboscidea and other mammalia. Evidences for the greater extension of

the Eocene seas than was formerly considered to be the case have been

discovered around Sokoto. During Miocene times Passarge considers that the

region of the Zambezi underwent extreme desiccation.

The effect of the Glacial epoch in Europe is shown in northern Africa by

the moraines of the higher Atlas, and the wider extension of the glaciers

on Kilimanjaro, Kenya and Ruwenzori, and by the extensive accumulations of

gravel over the Sahara.

The earliest signs of igneous activity in Africa are to be found in the

granites, intrusive into the older rocks of the Cape peninsula, into those

of the Transvaal, and into the gneisses and schists of Central Africa. The

Ventersdorp boulder beds of the Transvaal may be of early palaeozoic age;

but as a whole the palaeozoic period in Africa was remarkably free from

volcanic and igneous disturbances. The close of the Stormberg period

(Rhaetic) was one of great volcanic activity in South Africa. Whilst the

later Secondary and Tertiary formations were being laid down in North

Africa and around the margins of the rest of the continent, Africa received

its last great accumulation of strata and at the same time underwent a

consecutive series of earth-movements. The additional strata consist of the

immense quantities of volcanic material on the plateau of East Africa, the

basalt flows of West Africa and possibly those of the Zambezi basin. The

exact period of the commencement of volcanic activity is unknown. In

Abyssinia the Ashangi traps are certainly post-Oolitic. In East Africa the

fissure eruptions are considered to belong to the Cretaceous. These early

eruptions were followed by those of Kenya, Mawenzi, Elgon, Chibcharagnani,

and these by the eruptions of Kibo, Longonot, Suswa and the Kyulu

Mountains. The last phase of vulcanicity took place along the great

meridional rifts of East Africa, and though feebly manifested has not

entirely passed away. In northern Africa a continuous sequence of volcanic

events has taken place from Eocene times to latest Tertiary; but in South

Africa it is doubtful if there have been any intrusions later then

Cretaceous.

During this long continuance of vulcanicity, earth-movements were in

progress. In the north the chief movements gave rise to the system of

latitudinal folding and faulting of the Moroccan and Algerian Atlas, the

last stages being represented by the formation of the Algerian and Moroccan

coast-outline and the sundering of Europe from Africa at the Straits of

Gibraltar. Whilst northern Africa was being folded, the East African

plateau was broken up by a series of longitudinal rifts extending from

Nyasaland to Egypt. The depressed areas contain the long, narrow,

precipitously walled lakes of East Africa. The Red Sea also occupies a

meridional trough.

Lastly there are the recent elevations of the northern coastal regions,

the Barbary coast and along the east coast. (W. G.*)

III. ETHNOLOGY In attempting a review of the races and tribes which

inhabit Africa, their distribution, movements and culture, it is advisable

that three points be borne in mind. The first of these is the comparative

absence of natural barriers in the interior, owing to which

intercommunication between tribes, the dissemination of culture and tribal

migration have been considerably facilitated. Hence the student must be

prepared to find that, for the most part, there are no sharp divisions to

mark the extent of the various races composing the population, but that the

number of what may be termed ``transitional'' peoples is unusually large.

The second point is that Africa, with the exception of the lower Nile

valley and what is known as Roman Africa (see AFRICA, ROMAN), is, so far as

its native inhabitants are concerned, a continent practically without a

history, and possessing no records from which such a history might be

reconstructed. The early movements of tribes, the routes by which they

reached their present abodes, and the origin of such forms of culture as

may be distinguished in the general mass of customs, beliefs, &c., are

largely matters of conjecture. The negro is essentially the child of the

moment; and his memory, both tribal and individual, is very short. The

third point is that many theories which have been formulated with respect

to such matters are unsatisfactory owing to the small amount of information

concerning many of the tribes in the interior.

The chief African races.

Excluding the Europeans who have found a home in various parts of Africa,

and the Asiatics, Chinese and natives of India introduced by them (see

section History below), the population of Africa consists of the following

elements: —the Bushman, the Negro, the Eastern Hamite, the Libyan and the

Semite, from the intermingling of which in various proportions a vast

number of ``transitional'' tribes has arisen. The Bushmen (q.v.), a race of

short yellowish-brown nomad hunters, inhabited, in the earliest times of

which there is historic knowledge, the land adjoining the southern and

eastern borders of the Kalahari desert, into which they were gradually

being forced by the encroachment of the Hottentots and Bantu tribes. But

signs of their former presence are not wanting as far north as Lake

Tanganyika, and even, it is rumoured, still farther north. With them may be

classed provisionally the Hottentots, a pastoral people of medium stature

and yellowish-brown complexion. who in early times shared with the Bushmen

the whole of what is now Cape Colony. Though the racial affinities of the

Hottentots have been disputed, the most satisfactory view on the whole is

that they represent a blend of Bushman, Negroid and Hamitic elements.

Practically the rest of Africa, from the southern fringe of the Sahara and

the upper valley of the Nile to the Cape, with the exception of Abyssinia

and Galla and Somali-lands, is peopled by Negroes and the ``transitional''

tribes to which their admixture with Libyans on the north, and Semites

(Arabs) and Hamites on the north-east and east, has given rise. A slight

qualification of the last statement is necessary, in so far as, among the

Fula in the western Sudan, and the Ba-Hima, &c., of the Victoria Nyanza,

Libyan and Hamitic elements are respectively stronger than the Negroid. Of

the tracts excepted, Abyssinia is inhabited mainly by Semito-Hamites

(though a fairly strong negroid element can be found), and Somali and Galla-

lands by Hamites. North of the Sahara in Algeria and Morocco are the

Libyans (Berbers, q.v.), a distinctively white people, who have in certain

respects (e.g. religion) fallen under Arab influence. In the north-east the

brown-skinned Hamite and the Semite mingle in varied proportions. The

Negroid peoples, which inhabit the vast tracts of forest and savanna

between the areas held by Bushmen to the south and the Hamites, Semites and

Libyans to the north, fall into two groups divided by a line running from

the Cameroon (Rio del Rey) crossing the Ubangi river below the bend and

passing between the Ituri and the Semliki rivers, to Lake Albert and thence

with a slight southerly trend to the coast. North of this line are the

Negroes proper, south are the Bantu. The division is primarily

philological. Among the true Negroes the greatest linguistic confusion

prevails; for instance, in certain parts of Nigeria it is possible to find

half-a-dozen villages within a comparatively small area speaking, not

different dialects, but different languages, a fact which adds greatly to

the difficulty of political administration. To the south of the line the

condition of affairs is entirely different; here the entire population

speaks one or another dialect of the Bantu Languages (q.v..) As said

before, the division is primarily linguistic and, especially upon the

border line, does not always correspond with the variations of physical

type. At the same time it is extremely convenient and to a certain extent

justifiable on physical and psychological grounds; and it may be said

roughly that while the linguistic uniformity of the Bantu is accompanied by

great variation of physical type, the converse is in the main true of the

Negro proper, especially where least affected by Libyan and Hamitic

admixture, e.g. on the Guinea coast. The variation of type among the Bantu

is due probably to a varying admixture of alien blood, which is more

apparent as the east coast is approached. This foreign element cannot be

identified with certainty, but since the Bantu seem to approach the Hamites

in those points where they differ from the Negro proper, and since the

physical characteristics of Hamites and Semites are very similar, it seems

probable that the last two races have entered into the composition of the

Bantu, though it is highly improbable that Semitic influence should have

permeated any distance from the east coast. An extremely interesting

section of the population not hitherto mentioned is constituted by the

Pygmy tribes inhabiting the densely forested regions along the equator from

Uganda to the Gabun and living the life of nomadic hunters. The affinities

of this little people are undecided, owing to the small amount of knowledge

concerning them. The theories which connected them with the Bushmen do not

seem to be correct. It is more probable that they are to be classed among

the Negroids, with whom they appear to have intermingled to a certain

extent in the upper basin of the Ituri, and perhaps elsewhere. As far as is

known they speak no language peculiar to themselves but adopt that of the

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