GEOLOGY OF AFRICA--ANTIQUITY OF MAN.
The General Geological Formation of the Continent -- The Want of
Comprehensive Investigation -- Singular Facts as to the Desert of
Sahara -- The Question of the Antiquity of Man -- Is Africa the
Birth-place of the Human Race? Opinions of Scientists Tending to
Answer in the Affirmative -- Darwinism.
It is to be greatly regretted that no comprehensive geological surveys
of Africa have ever been made; because there are certain questions,
eventually to be settled by geology, whose determination, it appears to
be agreed, will be finally resolved by investigations in this continent.
In a volume of this nature, designed for the general reader, those facts
and reasonings only need be referred to which may be supposed to have
the most interest. Reference has already been made to Sir Roderick
Murchison’s exposition of the trough-shaped form of South Africa in his
discourse before the Royal Geographical Society in 1852--an exposition
which was so remarkably substantiated by Dr. Livingstone in his journey
across the continent from Loanda to Kilimane. Though in its geographical
configuration Africa is not greatly unlike South America, in its
geological structure it much more resembles the northern continent of
the western hemisphere. The Appalachian range of mountains extending
through nearly the whole of the eastern portion of North America,
parallel with the coast, and the Rocky Mountains and Sierra Nevadas
in the west, bear a notable resemblance to those ranges of mountains in
Africa, which, rising first in the northern portions of Senegambia,
pursue a south-easterly, then a southerly course to near the southern
limit of the continent, when they sharply bend toward the northeast, and
with many lofty peaks, some of which reach the region of eternal snow,
pass through Mozambique, Zanguebar, and end not until after they have
passed through Abyssinia and Nubia, and penetrated the limits of Egypt.
In Tripoli, Tunis, Algeria, and Morocco, is the Atlas range, between
which and the beginning of the other the distance is hardly so great as
that between the southern limits of the Appalachian range and the
mountains of Mexico. The course of each of the great rivers of these
continents is also across the degrees of latitude instead of generally
parallel with the equator, as is the case with the great river of South
America. There is a similarity also between North America and Africa in
an extensive system of inland lakes of fresh water and vast extent.
[Illustration: ARAB CHIEF OF CENTRAL AFRICA.]
The geological structure of the mountains of Africa, especially of South
Africa, appears to be quite uniform. They have a nucleus of granite
which often appears at the surface and forms the predominating rock, but
in the greater proportion of the mountains, perhaps, the granite is
overlain by vast masses of sandstone, easily distinguished by the
numerous pebbles of quartz which are embedded in it. The summit, when
composed of granite, is usually round and smooth, but when composed of
the quartzose sandstone is often perfectly flat. Of this Table Mount,
in South Africa, is a notable illustration. The thickness of this
stratum of sandstone is sometimes not less than 2,000 feet. Such is the
case in the Karoo mountains of Cape Colony. When thus appearing, it may
be seen forming steep, mural faces, resembling masonry, or exhibiting a
series of salient angles and indentations as sharp, regular, and
well-defined as if they had been chiselled. With the granite are often
associated primitive schists, the decomposition of which seems to have
furnished the chief ingredients of the thin, barren clay which forms the
characteristic covering of so much of the South African mountains. In
some places, more recent formations appear, and limestone is seen
piercing the surface. The geological constitution of the Atlas
Mountains, in northwestern Africa, presents old limestone alternating
with a schist, often passing to a well-characterized micaceous schist,
or gneiss, the stratification of which is exceedingly irregular.
Volcanic rocks have here been found in small quantities. There are veins
of copper, iron, and lead.
In Egypt we find the alluvial soil a scarcely less interesting object of
study than the rocks upon which it rests. These are limestone,
sandstone, and granite, the latter of which, in Upper Egypt, often rises
1,000 feet above the level of the Nile. Not many years ago were
discovered about 100 miles east of the Nile, and in 28 deg. 4 min. of
north latitude the splendid ruins of the ancient Alabastropolis, which
once derived wealth from its quarries of alabaster. Farther south are
the ancient quarries of jasper, porphyry, and verd antique. The emerald
mines of Zebarah lay near the Red Sea.
The Atlas range in Algeria is better known than elsewhere. It is as
described above, but at Calle there are distinct traces of ancient
volcanoes. Iron, copper, gypsum, and lead are found in considerable
quantities. Cinnabar is found in small quantities. Salt and thermal
springs abound in many parts of Algeria, amethysts in Morocco, slates in
Senegambia, and iron in Liberia, Guinea, the Desert of Sahara and many
other parts of Africa.
Gold, gold-dust, and iron are among the best known of the mineral riches
of Africa, and are the most generally diffused throughout the continent.
In the country of Bambouk, in Senegambia, most of the gold which finds
its way to the west coast is found. Here the mines are open to all, and
are worked by natives who live in villages. The richest gold mine of
Bambouk, and the richest, it is believed, yet discovered in Africa, is
that of Natakoo--an isolated hill, some 300 feet high and 3,000 feet in
circumference, the soil of which contains gold in the shape of lumps,
grains, and spangles, every cubic foot being loaded, it is said, with
the precious metal. The auriferous earth is first met with about four
feet from the surface, becoming more abundant with increase of depth. In
searching for gold the natives have perforated the hill in all
directions with pits some six feet in diameter and forty or fifty feet
deep. At a depth of twenty feet from the surface lumps of pure gold of
from two to ten grains weight are found. There are other mines in this
portion of Africa, gold having been found distributed over a surface of
1,200 square miles. The precious metal is not only found in hills, the
most of which are composed of soft argillaceous earth, but in the beds
of rivers and smaller streams, so that the lines of Bishop Heber’s
well-known missionary hymn are truthful as well as poetical:--
“Where Afric’s sunny fountains,
Roll down their golden sands.”
The gold mines of Semayla, which are some forty or fifty miles northward
of those of Natakoo, though nearly as rich as the latter, are in hills
of rock and sandstone, which substances are pounded in mortars that the
gold may be extracted. Barth judged that gold would be found in the
Benue river, the principal eastern tributary of the Niger. Gold, silver,
iron, lead and sulphur have been found in large quantities, and were
long profitably mined in the mountainous districts of Angola. In Upper
Guinea gold and iron are deposited in granitic or schistose rocks. The
interior contains vast quantities of iron which might be easily mined,
but the natives are not sufficiently enterprising to accomplish much in
this respect. Gold is also obtained in the beds of some of the rivers of
Guinea. In Mozambique, on the east coast, the Portuguese have for a
great length of time had a considerable commerce in gold obtained from
mines near the Zambezi, in the region near the western limit of that
province. It has already been stated that here Dr. Livingstone
discovered deposits of coal. Along the Orange and Vaal rivers, in
extreme South Africa, have recently been discovered diamond fields which
some noted scientists believe will yet prove to be among the richest in
the world.
[Illustration: ARRIVAL OF THE EXPEDITION ON THE BANKS OF THE ZAMBESI.]
Perhaps the portions of Africa which are the most interesting on account
of geological investigations which have been made, are the valley of the
Nile in Egypt, and the Desert of Sahara. It is well known that the river
Nile annually overflows its banks in Egypt, and the inundation remaining
a considerable period, a thin layer of soil is each year added to that
which existed there before. This Nile mud, as it is called by
geologists, has been the subject of considerable scientific examination
for many years. In his work upon the “Geological Evidences of the
Antiquity of Man,” Sir Charles Lyell gives a full account of certain
systematic borings in the Nile mud which were made between the years
1851 and 1854, under the superintendency of Mr. Leonard Horner, but who
employed to practically conduct the examinations an intelligent,
enterprising, and faithful Armenian officer of engineers, Hekekyan Bey,
who had for many years pursued scientific studies in England, was in
every way qualified for the task, and, unlike Europeans, was able to
endure the climate during the hot months, when the waters of the Nile
flow within their banks. Sir Charles Lyell states that the results of
chief importance arising out of this inquiry were obtained from two sets
of shafts and borings--sunk at intervals in lines crossing the great
valley from east to west. One of these consisted of fifty-one pits and
artesian perforations made where the valley is sixteen miles wide
between the Arabian and the Libyan deserts, in the latitude of
Heliopolis, about eight miles above the apex of the delta. The other
line of pits and borings, twenty seven in number, was in the parallel
of Memphis where the valley is five miles wide. Besides Hekekyan Bey,
several engineers and some sixty workmen, inured to the climate, were
employed for several years, during the dry season, in the furtherance of
these interesting investigations.
It was found that in all the works the sediment passed through was
similar in composition to the ordinary Nile mud of the present day,
except near the margin of the valley, where thin layers of quartzose
sand, such as is sometimes blown from the adjacent desert by violent
winds, were observed to alternate with the loam. A remarkable absence of
lamination and stratification, the geologist goes on to say, was
observed almost universally in the sediment brought up from all points
except where the sandy layers above alluded to occurred, the mud closely
agreeing in character with the ancient loam of the Rhine. Mr. Horner
attributes this want of all indication of successive deposition to the
extreme thinness of the film of matter which is thrown down annually on
the great alluvial plain during the season of inundation. The tenuity of
this layer must indeed be extreme, if the French engineers are tolerably
correct in their estimate of the amount of sediment formed in a century,
which they suppose not to exceed on the average five inches. It is
stated, in other words, that the increase is not more than the twentieth
part of an inch each year, or one foot in the period of 240 years. All
the remains of organic bodies found during these investigations under
Hekekyan Bey belonged to living species. Bones of the ox, hog, dog,
dromedary, and ass were not uncommon, but no vestiges of extinct
mammalia were found, and no marine shells were anywhere detected. These
excavations were on a large scale, in some instances for the first
sixteen or twenty-four feet. In these pits, jars, vases, and a small
human figure in burnt clay, a copper knife, and other entire articles
were dug up; but when water soaking through from the Nile was reached,
the boring instrument used was too small to allow of more than fragments
of works of art being brought up. Pieces of burnt brick and pottery were
constantly being extracted, and from all depths, even where they sank
sixty feet below the surface toward the central parts of the valley. In
none of these cases did they get to the bottom of the alluvial soil. If
it be assumed that the sediment of the valley has increased at the rate
of six inches a century, bricks at the depth of sixty feet have been
buried 12,000 years. If the increase has been five inches a century,
they have lain there during a period of 14,400 years. Lyell states
further on that M. Rosiere, in the great French work on Egypt has
estimated the rate of deposit of sediment in the delta at two inches and
three lines in a century. A fragment of red brick has been excavated a
short distance from the apex of the delta at a depth of seventy-two
feet. At a rate of deposit of two and a-half inches a century, a work of
art seventy-two feet deep must have been buried more than 30,000 years
ago. Lyell frankly states, however, that if the boring was made where an
arm of the river had been silted up at a time when the apex of the delta
was somewhat further south, or more distant from the sea than now, the
brick in question might be comparatively very modern. It is agreed by
the best geologists that the age of the Nile mud cannot be accurately,
but only approximately calculated by the data thus far furnished. The
amount of matter thrown down by the waters in different parts of the
plain varies so much that to strike an average with any approach to
accuracy must be most difficult. The nearest approach, perhaps, as has
been observed by Baldwin, to obtaining an accurate chronometric scale
for ascertaining the age of the deposits of the Nile at a given point,
was made near Memphis, at the statue of King Rameses. It is known that
this statue was erected about the year 1260 B. C. In 1854 it had stood
there 3,114 years. During that time the alluvium had collected to the
depth of nine feet and four inches above its base, which was at the rate
of about three and a half inches in each century. Mr. Horner found the
alluvium, below the base of the statue, to be thirty feet deep, and
pottery was found within four inches of the bottom of the alluvium. If
the rate of accumulation previous to the building of the statue had been
the same as subsequently, the formation of the alluvium began, at that
point, about 11,660 years before the Christian era, and men lived there
some 12,360 years ago, cultivating the then thin soil of the valley. But
it would appear to be certain that the average deposit is so slight
annually that many centuries more than those formerly quite universally
received as the age of the world for the stage of mankind’s achievements
must have passed since the work of man’s hands have been buried under
these vast deposits of alluvium. Thus, geology insists, is the fact of
man’s existence, long before the historic era, conclusively established.
[Illustration: AN OBJECT OF INTENSE INTEREST.]
The Desert of Sahara presents some interesting facts of the same nature.
It has already been stated that this part of Africa was ocean within a
comparatively recent geological period. Tristram and several French
officers of scientific attainments, who have made geological
examinations of large portions of the desert have shown that the
northern margin is lined with ancient sea-beaches and lines of
terraces--the “rock-bound coasts” of the old ocean. Numerous salt-lakes
exist in the desert which are tenanted by the common cockle. A species
of _Haligenes_ which inhabits the Gulf of Guinea is found in a salt lake
in latitude 30 deg. north and longitude 7 deg. east, separated,
therefore, from its present marine habitat by the whole extent of the
great desert, and the vast expanse of Soudan and Guinea. Geologists
hence conclude that the existing fauna, including man, occupied Africa
long before the Sahara became dry land. Reference has been made in the
preceding chapter to the supposed remarkably beneficent effect this
great expanse of desert, heated sands, and hot air, has upon the
climate, and consequently upon the civilization of Europe.
It is probable that from the fact that Sahara was about the last
extensive portion of earth to be abandoned by the ocean, that the
general opinion became prevalent that the continent of Africa was,
geologically, the most recent of the grand divisions of the earth.
Though supposed to be the oldest in civilization, it has been supposed
to be the youngest in geological constitution. I am informed by
scientific men that on account of recent investigations and reasonings,
the opinion has for some time been gaining ground that Africa is likely
to be shown to be the oldest part of the globe in both respects, and to
have been the original birthplace of the race of man.
The negroid race, comprehending the Negroes, Hottentots, and Algutos,
are, it is claimed by many scientists, the most ancient of all the types
of mankind, and since their appearance on earth vast geographical
changes have taken place. Continents have become ocean and sea has
become land. “The negroes,” says Lubbock, “are essentially a
non-navigating race, they build no ships, and even the canoes of the
Feejeeans are evidently copied from those of the Polynesians. Now what
is the geographical distribution of the race? They occupy all Africa
south of Sahara, which neither they nor the rest of the true African
fauna have ever crossed. And though they do not occur in Arabia, Persia,
Hindoostan, Siam, or China, we find them in Madagascar, and in the
Andaman Islands; not in Java, Sumatra, or Borneo, but in the Malay
Peninsula, in the Phillippine Islands, New Guinea, the New Hebrides, New
Caledonia, the Feejee Islands, and in Tasmania. This remarkable
distribution is perhaps most easily explicable on the hypothesis that
since the negroid race came into existence there must have been an
immense tract of land or a chain of islands stretching from the eastern
coast of Africa right across the Indian ocean; and secondly that the
sea then occupied the area of the present great desert. In whatever
manner, however, these facts are to be explained, they certainly
indicate that the race is one of very great antiquity.” “It is
manifest,” says Baldwin in his Pre-Historic Nations, “that Africa at a
remote period was the theatre of great movements and mixtures of peoples
and races, and that its interior countries had then a closer connection
with the great civilizations of the world than at any time during the
period called historical.” It is the opinion of this writer that the
Cushite race--the Ethiopians of Scripture--appeared first in the work of
civilization, and that in remote antiquity that people exerted a mighty
and wide-spread influence in human affairs, whose traces are still
visible from farther India to Norway. Nor is he by any means alone in
the opinion that the Carthagenians, ages ago, sent their ships across
the Atlantic to the American continent. The Cushites, or original
Ethiopians originated in Arabia, but their descendents are still found
in northern Africa from Egypt to Morocco. Of this race are the Tuariks,
the robbers of the Great Desert, to this day among the most magnificent
specimens of physical man to be found anywhere on the globe.
The final solution of these problems of the geological status of Africa,
and the great antiquity of man can but be of the greatest interest to
all thoughtful persons. Unquestionably their solution will be greatly
hastened, should Dr. Livingstone succeed in the great enterprise upon
which he is now engaged, and soon make known to the world the true
sources of the Nile. His success therein would stimulate endeavor,
study, exploration, and, it is to be hoped, comprehensive and systematic
surveys of a continent the evidences of whose civilization in remote
ages lie buried among the debris of countless centuries.
We know, from the imperfect investigations which have already been made,
that cities have been engulfed in the sands of Sahara. We know that vast
changes have taken place in the physical structure of the continent of
Africa and of the world since the negro race first appeared. It is not
improbable, therefore, that where for so many ages beasts of prey and
savage tribes have occupied a land oppressed with heat and burdened with
many ills, there may yet be found evidences of former civilization and
power in greatest possible contrast to present barbarism and national
weakness. And who shall say that when the face of the continent was
changed, whether by a great convulsion or by a gradual process, some of
the people did not migrate northward, cross the Mediterranean and
populate the continent which has since become the abode of the highest
civilization and the greatest intellectual culture? Who shall say that
these races of remote antiquity were not possessed of culture and arts
and literature placing them very high in the scale of civilization?
Within the historic period those nations have passed away which were the
acknowledged parents of modern culture and art. The power and
versatility of the human mind, reason, eloquence, and poetry, were most
sublimely illustrated by the Greeks, whose works still remain to benefit
and instruct mankind. Yet the freedom and power of this wonderful people
have for more than twenty centuries been annihilated. The people, in
the eloquent diction of Macaulay, have degenerated into timid slaves;
the language into a barbarous jargon; and the beautiful temples of
Athens “have been given up to the successive depredations of Romans,
Turks, and Scotchmen.” The vast empire of Rome has passed entirely away
within a few centuries. She had herself annihilated Carthage leaving
nothing, as we have seen, of the arts, literature, or institutions of a
people whose ships had sailed on every wave from the Hellespont to the
Baltic, and, not improbably, from the Mediterranean to the delta of the
Mississippi. Other great nations are also known to have passed away or
been destroyed, the nature of their civilization and institutions being
left to conjecture based upon a few monuments or a few literary remains
preserved by foreign writers. It being once established that man existed
ages before what is commonly called the beginning of the historic period
it would be simply logical, considering many national destructions which
have occurred during the historic period, to conclude by analogy that
races of remote antiquity flourished and passed away leaving no sign,
which has been yet discovered, of their power and civilization. It is
evident the historian Macaulay thinks it not improbable such may be the
fate of England, and he expressly states in a well-known passage that
the time may come when only a single naked fisherman may be seen in the
river of the ten thousand masts. It is difficult, if not impossible, for
mankind entirely to overcome the tendency to decay.
[Illustration: ARAB SLAVE TRADERS.]
We shall presently see that Africa is a field upon which must soon be
decided a great issue of politico-social importance; an issue which
involves the abolition of polygamy, domestic slavery, and the
suppression of the foreign slave trade. From what has gone before in
this volume, it will have been seen that here, too, are likely to be
most conclusively demonstrated the vast age of the world, the great
antiquity of man, and the nature of his origin. In comparison of the
settlement of this issue and the solution of these problems of science,
even the discovery of the true sources of the Nile may be regarded as
unimportant, except for the reason that Dr. Livingstone’s great
achievement will arouse other men of science to similar sacrifices,
labors, and fortitude. Thus Africa is found to present another
remarkable contrast for our contemplation; for while civilization is
there at a lower ebb than in any other grand division of the globe, the
highest intellectual efforts of the most astute thinkers of the times
are turning their best efforts thitherward, in the confident hope of
greatly enlarging the sphere of human knowledge, and of extending the
triumphs of science and civilization.
There are many, it is true, who imagine that the scientific inquiries
which are being made in regard to the great age of the world, the races
which existed long anterior to the historic period, and the origin of
the human species are founded in a spirit of skepticism and hostility to
Christian civilization, or, rather to Christianity as a religion.
Doubtless there are many scientists who put no faith in Holy Writ, as
much of it has been commonly understood. Others, and those among the
most distinguished of men, are no less devout believers in Christianity
than they are firm believers in the great age of the world and antiquity
of man. The devotees of Christianity have in not a few instances
mistaken an ally for an enemy. This was notably the fact, in an example
which is here most appropriate, in the case of the modern origin of the
science of astronomy. The Christian church, as then existing, pronounced
as religious heresy the plain truth that the world moves, and that the
sun neither rises nor sets, but is stationary--the sublime centre of a
universe of planets and stars, and, perhaps, inhabited worlds, whose
movements must be controlled, as the vast system must have been
originated, by One of infinite wisdom and power and goodness. In due
course of time it was discovered that astronomy did not militate against
Christianity, and the church not only ceased putting astronomers in
prison, but learned that the acceptance of all truth, come from whatever
source it may, is a Christian duty. And many of the most distinguished
astronomers have been no less earnest exemplars of the Christian system
of religion than any monk who ever wore the pavements of a monastery and
left the world no wiser or better than he found it.
As it was with astronomy, so it has been even of late years with the
science of geology. The era of imprisonment for heresy had indeed passed
by when men began to construct a comprehensive science on the study of
rocks; but as their revelations became more extensive and more
wonderful, it again appeared to many that here had arisen a formidable
foe of Christianity, and the new science was assailed accordingly. It
has not turned out that these disputants were as wise as they were
zealous and as they were undoubtedly sincere. Though the sun never rises
and never sets, we should be stupid indeed were we always, when speaking
of his appearance on our horizon, or his disappearance therefrom, to
state the fact in words of scientific accuracy. The world has never yet
been slow enough justly to permit such waste of time and words. Not only
the almanac-makers, but the most celebrated astronomers persist in
saying that the sun rises and the sun sets. And, properly understood, it
is perfectly true though scientifically false. To all appearance and for
all practical purposes to the inhabitants of earth the sun does rise and
set, and when one so says, whether inspired or uninspired, one simply
conveys the idea that he intends to convey, and this is the province of
language. As astronomy appeared to be utterly opposed by certain
expressions in Scripture, but was found not to be, upon more liberal
construction of the language, as well as more philosophical, so geology
appeared to be, in its apparent demonstration of the vast age of the
world, and, later, of the great antiquity of man, hostile to the
received canons of the church, and especially subversive of the Mosaic
account of creation and the generally received system of chronology. The
conflicts thus arising have dissipated many erroneous theological
constructions and dogmas, but they have in no manner affected the
foundations of Christianity. There are many eminent geologists who are
earnest Christians, and though Dr. Livingstone himself has done geology
incalculable service he has done Christianity incalculably more. It may
well be doubted whether any single theologian of the age has conferred
more valuable service upon Christianity than Hugh Miller, the great
geologist of Scotland, whose scientific works are, perhaps, the most
fascinating of any in the English language.
There can be, then, no well-grounded fear of science overturning
Christianity. It is more likely thereby to be in the end not only more
thoroughly and correctly understood, but more firmly established and
more generally adopted. Even the inquiry which is now receiving so much
attention from men of thought--that into the origin of man--need not be
deemed as fraught with any real danger to the system which has given the
world its present civilization. Were it possible to establish Mr.
Darwin’s theory of evolution--and that it is more than a theory cannot
be claimed for it by its most devoted advocate--and establish man’s
origin in the ape, still would the act of his creation into man from ape
be an act of infinite power and goodness. For the infinite power and
goodness of the act consist in the creation, by some means, of a being
of intellectual and moral attributes. The act of divine power is in
breathing into the nostrils the breath of life, and causing the being to
become a living soul. Even Mr. Darwin will not dispute that the ape was
in the long ages evolved from dust, nor that, so far as science has
shown or probably ever can show, there is no being in the universe with
capacity to evolve thought except only God, as shown in His manifold
works, and man.
Whatever may be the result, therefore, of the interesting inquiries in
commerce, religion, geography, geology, ethnology which now are being
more and more directed toward Africa with each passing year, we may
quite safely conclude, judging from the results of the past, that
Christianity will come forth out of the conflicts that may arise,
whether they be scientific or of other nature, with renewed beauty and
power; with more liberal and enlightened views, doubtless, upon some
questions which have been erroneously considered, but with greater
influence on this account, and with brighter prospects of more speedily
than might have been but for these conflicts extending the rule of her
pure and beneficent morality among all the nations and tribes of men.
[Illustration]