We have now to adjust our time-telescope to a wider range, and see

what the Quaternary or glacial period teaches us as to the antiquity

of man. The first remark is, that if the post-glacial period is much

longer than that for which we have historical records, the glacial

exceeds the post-glacial in a far higher proportion. The second, that

throughout the whole of this glacial period, from its commencement

to its close, we have conclusive evidence of the existence of man,

and that not only in a few limited localities, but widely spread over

nearly all the habitable regions of the earth.

The first point has been so conclusively established by all

geologists of all countries, from the time of Lyell down to the

present day, that it is unnecessary to enter on any detailed

arguments, and the leading facts may be taken as established. It may

be sufficient, therefore, if I give a short summary of those facts,

and quote a few of the instances which show the enormous lapse of

time which must have elapsed between the close of the tertiary and

the commencement of the modern epoch.

The glacial period was not one and simple, but comprised several

phases. During the Pliocene the climate was gradually becoming

colder, and either towards its close or at the commencement of the

Quaternary, this culminated in a first and most intense glaciation.

Ice-caps radiating from Scandinavia crept outwards, filling up the

North Sea, crossing valleys and mountains, and covering with their

boulders and moraines a wide circle, embracing Britain down to the

Thames valley, Germany to the Hartz mountains, and Russia almost as

far east as the Urals. In North America a still more massive ice-cap

overflowed mountain ranges 3000 feet high, and covered the whole

eastern half of the continent with an unbroken mantle of ice as far

south as New York and Washington.

At the same time every great mountain chain and high plateau sent

out enormous glaciers, which, in the case of the Alps, filled up

the valley of the Rhone and the Lake of Geneva, buried the whole of

the lower country of Switzerland under 3000 feet of ice, and left

the boulders of its terminal moraine, carried from the Mont Blanc

range, at that height on the opposite range of the Jura. Nor is this

a solitary instance. We find everywhere traces of enormous glaciers

in the Pyrenees and Carpathians, the Atlas and Lebanon, the Taurus

and Caucasus, the highlands of Scotland, Ireland, and Wales; in the

Rocky Mountains and Sierra Nevada; the Andes and Cordilleras of South

America; in South Africa and in New Zealand. These may not have all

been simultaneous, but they certainly all belong to the same period

of the great glaciation, and show that it must have been affected by

some general cause, and not been entirely due to mere local accidents.

How this first great glacial period came on, or how long it lasted,

we do not know, unless Croll's astronomical theory, which will be

considered later, affords a clue. But we know generally that it must

have lasted for an immense time from the amount of work done and the

changes which took place. The ice, which covered so great a portion

of the northern hemisphere, was not a polar ice-cap, but spread

outwards in all directions from great masses of elevated land, as

is proved conclusively from the direction of the striæ which were

engraved by it on the subjacent rocks. This land must have been more

elevated than at present, so as to rise, like Greenland, far into

the region of perpetual snow, where all rain falls and accumulates

in the solid form; and also to supply the enormous mass of _débris_

which the ice-caps and glaciers left behind them. It is not too

much to say that a million of square miles in Europe, and more in

North America, were covered by the _débris_ of rocks ground down by

these glaciers, and often to great depths. Most of the _débris_ of

the first glaciation have been removed by denudation, or ploughed

out by the second great advance of the ice, leaving only the larger

and harder boulders to testify to their extent; but enough remains

to show that the first series of boulder-clays and drifts must have

been on a scale larger than those of the second and subsequent

glaciations, which now form the superficial stratum of so much of the

earth's surface, and often attain a depth of several hundred feet.

Wright, in his _Ice Age in North America_, estimates that "not less

than 1,000,000 square miles of territory in North America is still

covered with an average depth of fifty feet of glacial _débris_."

However, this first period of elevation and of intense glaciation

passed away, and was succeeded by one of depression and of milder

climate. Whether or no the depression was due, as some think, to

the weight of the enormous mass of ice weighing down the yielding

crust of the earth, and whether or no the milder climate was partly

occasioned by this depression letting in the sea, the fact is certain

that the two coincided, and were general and not merely local

phenomena. Marine shells at the top of what are now high hills, and

which during the preceding glaciation were probably higher, attest

the fact that a large amount of land must have sunk below the sea

towards the close of this first glacial period. It is equally clear

that a long inter-glacial period ensued, during which many changes

took place in the geographical conditions and in the fauna and flora,

requiring a very long time. Thus Britain, which had been reduced to

an Arctic Archipelago, in which only a few of the highest mountain

peaks emerged as frozen islands, became united to the continent, and

the abode of a fauna consisting in great part of African animals. At

one time boreal shells were deposited, at the bottom of an Arctic

ocean, on what is now the top of Moel-Tryfen in Wales, a hill 1300

feet above the present sea-level; while at another the hippopotamus

found its way, in some great river flowing from the south, as far

north as Yorkshire, and the remains of African animals such as the

hyena accumulated in our caves. In Southern France we had at one time

a vegetation of the Arctic willow and reindeer moss, at another that

of the fig-tree and canary-laurel. When we consider that little if

any change has occurred either in geographical conditions or in fauna

or flora, within the historical period of some 10,000 years, it is

difficult to assign the time which would be sufficient to bring about

such changes by any known natural causes. And yet it comprises only

a portion of the glacial period, for after this inter-glacial period

had lasted for an indefinite time the climate again became cold, and

culminated in a second glaciation, which, if not equal to the first,

was still of extreme severity, and brought back ice-caps and glaciers

almost to their former limits, passing away slowly and with several

vicissitudes and alternate retreats and advances.

It is not always easy to determine the position of each individual

phase of the two glacial and the inter-glacial periods, for they

must often be intermixed, and the results of the last glaciation and

of subsequent denudation have to a great extent obscured those of the

earlier periods. But taking a general view of the glacial period as

a whole, there are a few leading facts which testify conclusively to

its immense antiquity. First, there is the amount of elevation and

depression. We have seen that marine Arctic shells have been found

on the top of Moel-Tryfen, 1300 feet above the present sea-level.

Nor is this an isolated instance, for marine drifts apparently of

the same character have been traced on the mountains of Scotland,

Wales, and Ireland to a height of between 2000 and 3000 feet. In

Norway, also, old sea beaches are found up to a height of 800 feet.

Nor are these great movements confined to the Old World or to limited

localities. According to Professor Le Conte, at the last meeting of

the Geological Congress at Washington, a great continental movement,

commencing in the later tertiary and terminating in the beginning of

the quaternary, caused changes of level amounting to 2500 or 3000

feet on both sides of the continent of North America.

Now elevation and depression of large masses of land are, as far as

we know anything certain about them, very slow processes, especially

in countries unaffected by recent volcanic action, which is the

case with nearly all the regions in North America and Europe which

were covered by the great ice-sheets. There has been little or no

perceptible change anywhere since the commencement of history, and

the only accurate measurements of changes now going on are those

made in Sweden, where it appears that in some cases elevation, and

in others depression, is taking place at the rate of about two and

a half feet in a century. In volcanic regions earthquakes have

occasionally caused movements of greater amount in limited areas,

but there is no trace of anything of the sort in these movements of

the glacial period which have apparently gone on by slight secular

changes in the earth's crust as they are now doing in Scandinavia.

But in this case a depression of 2000 feet, followed by an elevation

of equal amount, at Lyell's rate of two and a half feet per century,

would require 160,000 years, without allowing for any pauses during

the process. And this only embraces part of the whole glacial period,

for the depression did not begin until after the climax of the

first great glaciation, when the land probably stood higher than at

present. Of course the actual movements may have been more rapid,

but unless we resort to the exploded theories of cataclysms and

catastrophes, the time for such movements must have been very great.

An equally conclusive proof of the immense antiquity of the glacial

period is afforded by the formation known as the loess, which fills

up so many of the valley systems of Europe, Asia, and America to

great depths, and spreads over the adjacent table-lands. It is a

tranquil land deposit of fine glacial mud, from sheets of water which

inundated the country when great rivers from glaciated districts

ran at higher levels, and began to excavate their present valleys.

Lyell estimates the thickness of this deposit in the Rhine valley at

800 feet, and it is found at much higher levels on upland plains.

Now this loess is not a marine or lacustrine deposit, as is proved

by the shells it contains, which are all of land species; nor is it

a deposit of running water, for there are no sands or gravels, but

distinctly such a deposit from tranquil sheets of muddy water as is

now accumulated in Egypt by the inundations of the Nile. When the

Rhine brought down such volumes of muddy water from the glaciers of

the Alps as to overflow the upland plains, it must have flowed at a

level many hundred feet higher than its present valley, which must

have been since scooped out by sub-aërial denudation. The rate of

deposition of the Nile mud is about three inches per century, and

there seems no reason why that of the fine glacial mud should have

been more rapid, charged as the Nile is every year with mud from the

torrential rains of the Abyssinian highlands. At this rate it would

have required 320,000 years to accumulate the 800 feet of loess of

the Rhine valley. Here again the rate may have been faster, but it

is sufficient to show that an immense time must have elapsed, and

the loess is a distinctly glacial deposit, containing palæolithic

human remains and a pleistocene fauna, and embracing only a portion

of the quaternary period. Nor is it an isolated phenomenon confined

to Europe, but is found over the whole world wherever rivers have

flowed from regions which were formerly buried under ice and snow.

It is found in great force in the valleys of the Yang-tse-Kang and

the Mississippi, and Sir Charles Lyell, referring to the fossil human

bone found in it at Natchez, says--"My reluctance in 1846 to regard

the fossil human bone as of post-pliocene date arose, in part, from

the reflection that the ancient loess of Natchez is anterior in time

to the whole modern delta of the Mississippi. The table-land was,

I believe, once a part of the original alluvial plain or delta of

the great river before it was upraised. It has now risen more than

200 feet above its pristine level. After the upheaval, or during

it, the Mississippi cut through the whole fluviatile formation, of

which its bluffs are now formed, just as the Rhine has in many parts

of its valley excavated a passage through its ancient loess. If I

was right in calculating that the present delta of the Mississippi

has acquired, as a minimum of time, more than 100,000 years for its

growth, it would follow, if the claims of the Natchez man to have

coexisted with the mastodon are admitted, that North America was

peopled more than a thousand centuries ago by the human race. But,

even were that true, we could not presume, reasoning from ascertained

geological data, the Natchez bone was anterior in date to the antique

flint _haches_ of St. Acheul."

Human remains have since been found in the United States, both in the

loess and in drifts, which are presumably older; but even if this

were doubtful, the evidence would remain the same for the immense

time required for such a deposit, and there is abundant proof in

Europe, that human implements, and even skulls and skeletons, have

been found at considerable depths in the loess, along with remains of

the mammoth and other extinct animals.

It must be remembered also, that the loess is only one part of the

work due to glacial erosion. It is, in fact, only the deposit of the

fine mud ground from the rocks by glaciers, and carried down further

by rivers issuing from them than the coarser _débris_, which, as we

have seen, cover 1,000,000 square miles to an average depth of fifty

feet in North America alone. The volumes, therefore, of the loess

and of the _débris_ correspond, and tell the same story of enormous

erosion requiring immense periods of time.

Even in comparatively recent times striking proofs of immense

antiquity are afforded by the amounts of denudation and erosion which

have taken place since the ice disappeared and the lands and seas

assumed substantially their present contours and levels. I will give

one instance which, although comparatively modern, will come home

readily to most British readers. Dr. Evans in his _Ancient Stone

Implements_, referring to those found at Bournemouth 100 feet above

the present sea-level in the gravels of the old Solent river, which

then ran at that height, says--

"Who, standing on the edge of the lofty cliff at Bournemouth, and

gazing over the wide expanse of waters between the present shore and

a line connecting the Needles on the one hand and the Ballard-Down

Foreland on the other, can fully comprehend how immensely remote was

the epoch when what is now that vast bay was high and dry land, and

a long range of chalk downs, 600 feet above the sea, bounded the

horizon on the south? And yet this must have been the sight that met

the eyes of those primæval men who frequented that ancient river,

which buried their handiworks in gravels that now cap the cliffs,

and of the course of which so strange but indubitable a memorial

subsists, in what has now become the Solent Sea."

And the same may be said of the still wider strait which separates

England from France. No geologist could look either at the Needles

and Ballard Foreland, or at Shakespeare's Cliff and Cape Grisnez,

without a conviction that the chalk ridge was once continuous, and

has been worn away, inch by inch, by the very same process as is now

going on. Nor can the action of ice or river floods be evoked to

accelerate the process, for evidently it has throughout been a case

of marine erosion. The only question is whether this dates back even

into the later phases of the glacial period, for the opposite cliffs

show no sign of having been either depressed beneath the sea or

elevated above it, but rather appear to have stood at their present

level since the erosion began. In any case it can only have occupied

a comparatively short and recent phase of the glacial period, for

there is abundant evidence that the British islands have been

connected with the Continent in comparatively recent times.

Great, however, as is the antiquity shown by these comparatively

modern instances, they sink into insignificance compared with that

shown by a recent discovery, which I quote the more readily because

it rests on the high authority of Professor Prestwich, who has been

foremost among modern geologists in reducing the time required for

the glacial period and for the existence of man. This is afforded

by the upland gravels in Kent and Surrey, which are scattered over

wide areas of the chalk downs and green-sand, at elevations far

above existing valleys and watersheds, and which could only have

been deposited before the present rivers began to run, and when the

configuration of the country was altogether different. Quite recently

Mr. Harrison, a shopkeeper at Ightham in Kent, who is an ardent

field-geologist, discovered palæolithic implements, in considerable

numbers and in various localities, up to an elevation of 750 feet

above the sea level, in these gravels of the great southern drift.

These discoveries, which have since been repeated by other observers,

led Professor Prestwich to institute an exhaustive inquiry as to

these upland drifts; and the startling conclusion he arrives at

is, that the oldest of them, or great southern drift, in which the

implements are found, could only have come from a mountain range 2000

to 3000 feet high, which formerly ran from east to west in the line

of the anticlinal axis which runs down the centre of the present

Weald of Kent, between the north and south chalk-downs, and which has

been since worn down to the present low forest-ridge by sub-aërial

denudation. The reasoning by which this inference is supported seems

irresistible. The drift could not have been deposited by the present

rivers or with the present configuration of the country, for it is

found at levels 300 or 400 feet higher than the highest watersheds

between the existing valleys. It consists not only of chalk flints,

but to a great extent of cherts and sandstones, such as are found at

present in the forest-ridge of the Wealden and nowhere else. It must

have been brought by water, for the gravels are to a considerable

extent rounded and water-worn. This water must have run down-hill and

with considerable velocity during floods, from the size of the rolled

stones, and it must have come from the south, because the cherts

and grits are only found there, and because the levels at which the

gravels are found rise in that direction. By following these levels

as far as the present surface extends, which is to the southern

edge of the green-sand, it is easy to plot out what must have been

the continuation of this rising gradient to the south, and what the

elevation of the southern range in which these northward-flowing

streams took their origin. Prestwich has gone into the question in

full detail, and his conclusion is, that the height of this Wealden

ridge must have been at least 2800 feet, or in other words, that

about 2000 feet must have disappeared by denudation. This is the more

conclusive as Prestwich is the highest authority, and he approached

the subject with a bias for shortening rather than lengthening the

periods commonly assigned for the glacial epoch and the antiquity of

man.

The present average rate of denudation of continents has been

approximately measured by calculating the amount of solid matter

brought down by rivers. It varies a good deal according to the

nature of the area drained, but the average is about one foot in

3000 years. At this rate the time required for the removal of 2000

feet of the Wealden ridge would be no less than 6,000,000 years; but

of course this would be no fair test, as denudation would be vastly

more rapid than the present average rate, on hilly ranges and under

glacial conditions of climate. It is enough to say that the time

required must have been extremely great, and quite ample to fit in

with the most extended time required by Croll's theory of the varying

eccentricity of the earth's orbit.

It is to be noted also, that Prestwich pronounces part of this

high level or southern drift to be older than the Westleton pebble

drift which forms part of the Upper Pliocene series in Suffolk and

Norfolk, and which the Professor has traced over many of our southern

counties. If this conclusion is correct, it solves the problem of

tertiary man by showing numerous palæolithic implements in a stage

older than an undoubted Pliocene bed. The implements found in these

high-level southern drifts are all of a very rude type, and the

discovery is confirmed by similar implements having been found at

corresponding elevations on the chalk downs of Hertfordshire and on

the South Downs.[10]

[10] In a recent paper read to the Anthropological Society

by Professor Prestwich, in Feb. 1892, he confirms the above

statement, and says that 1452 specimens have now been found at

heights of from 400 to 800 feet, and extending over an area

of twenty miles in length; while similar implements have been

found on the South Downs near Eastbourne 350 feet above the sea

level; and at heights of 596 and 760 feet on the hills near

Dunstable. He says, "Looking at the very distinctive features

of those plateau implements, such as their rudeness of make,

choice of material, depth of wear and staining, peculiarity of

form--taken in conjunction with the extreme rarity of valley

forms--they constitute characters so essentially different from

those of the latter implements, that by these characters alone

they might be attributed to a more primitive race of men; and as

this view accords with the geological evidence, which shows that

the drift-beds on the chalk plateau with implements are older

than the valley drifts, I do not see how we are to avoid the

conclusion, that not only was the plateau race not contemporary

with the valley men, but also that the former belonged to a

period considerably anterior to the latter--either an early

glacial or a pre-glacial period."

I will mention only one other instance, which shows that the New

World confirms the conclusion as to the antiquity of the quaternary

age. The auriferous gravels of California consist of an enormous

mass of _débris_ washed down by pre-glacial or early glacial rivers

from the western slopes of the great coast range. During their

deposition they became interstratified with lavas and tuffs from

eruptions of volcanoes long since extinct, and finally covered by an

immense flow of basalts, which formed a gently inclined plane from

the Sierra Nevada to the Pacific. This plane was attacked by the

denudations of the existing river-courses, and cut down into a series

of flat-topped hills, divided by steep cañons and by the valleys of

the present great rivers. In one case, that of the Colombia river,

this denudation has been carried down to a depth of over 2000 feet,

and the river flows between precipitous cliffs of this height. The

present gold-mining is carried on mainly by shafts and tunnels driven

through superficial gravels and sheets of basalts and tuffs, to the

gravels of the pre-glacial rivers, which are brought down in great

masses by hydraulic jets. In a great number of these cases stone

implements of undoubted human origin have been found at great depths

under several successive sheets of basalts, tuffs, and gravels. Mr.

Skertchly, an eminent English geologist, who recently visited the

district, says of these gravels, "Whatever may be their absolute age

from a geological standpoint, their immense antiquity historically is

beyond question. The present great river system of the Sacramento,

Joaquin, and other rivers has been established; cañons 2000 feet deep

have been carried through lava, gravels, and into the bed rock; and

the gravels, once the bed of large rivers, now cap hills 6000 feet

high. There is ample ground for the belief that these gravels are of

Pliocene age, but the presence of objects of human formation invests

them with a higher interest to the anthropologist than even to the

geologist."

I will return to this subject more fully in a later chapter, when

dealing with the question of the human remains found in these

Californian gravels.

Those who wish to pursue the subject further will find abundant

evidence in the works of Lyell, Geikie, Evans, Boyd Dawkins, and

other modern geologists, and a popular summary of it in my _Modern

Science and Modern Thought_.

It is sufficient for my present purpose to have shown that even

taking the quaternary period alone, geology shows that there is an

abundant balance in the bank of Time to meet any demands that may be

made upon it by any of the kindred sciences. But it is to those we

must look for any chance of even an approximate measurement in years

or centuries, for geology and palæontology only show immense periods,

but give no certain information as to definite durations. The clue,

if any, must be sought in Croll's astronomical theory of the glacial

period, which I now proceed to consider.

CHAPTER IX.

THE GLACIAL PERIOD AND CROLL'S THEORY.

Causes of Glacial Periods--Actual Conditions of existing

Glacial Regions--High Land in High Latitudes--Cold alone

insufficient--Large Evaporation required--Formation of

Glaciers--They flow like Rivers--Icebergs--Greenland and

Antarctic Circle--Geographical and Cosmic Causes--Cooling of

Earth and Sun, Cold Spaces in Space, and Change in Earth's Axis,

reviewed and rejected--Precession alone insufficient--Unless

with High Eccentricity--Geographical Causes, Elevation of

Land--Aerial and Oceanic Currents--Gulf Stream and Trade

Winds--Evidence for greater Elevation of Land in America,

Europe, and Asia--Depression--Warmer Tertiary Climates--Alps and

Himalayas--Wallace's _Island Life_--Lyell--Croll's Theory--Sir

R. Ball--Former Glacial Periods--Correspondence with Croll's

Theory--Length of the different Phases--Summary--Croll's Theory

a Secondary Cause--Conclusions as to Man's Antiquity.

I turn from the effects to the causes of that great glacial

period which has been described in the last chapter. This line of

investigation is peculiarly interesting in the search after human

origins, for it affords the only chance of reducing the vague periods

of immense duration shown by geology, to something like a definite

chronology of years and centuries. If astronomical causes, the dates

of which admit of mathematical calculation, can be shown to have

been, if not the sole or principal, yet one of the causes which must

have influenced the phenomena of the glacial epoch, we may assume

these dates for the occurrence of the human remains which accompany

these phenomena. Otherwise we must fall back on immense antiquity,

which may mean anything from 50,000 or 100,000, to 500,000 or

1,000,000 years, since the first authentic evidence for palæolithic

man.

The first step towards an investigation of the cause of glacial

periods, is to consider what are the conditions of the actual ones

which are now prevailing. We have one such period in Greenland,

another in the Antarctic region, a third in high mountain chains like

those of Alaska, and of the Swiss and New Zealand Alps. In all these

cases we find certain common conditions. High land in high latitudes,

rising in great masses above the snow-line or temperature which

condenses water in the solid form; and winds which are charged with

great quantities of watery vapour raised by evaporation, to be so

condensed.

Cold alone is insufficient to produce glaciers and ice-caps, as may

be seen by the example of the coldest regions in the world, Siberia

and the tundras of Northern Asia and of North America, where the

earth is permanently frozen to a depth of many feet; but there are

no glaciers, The reason obviously is, that there is no sufficient

supply of moist air from warm oceans to furnish more snow in winter

than is melted in summer. Heat is in a certain sense as necessary

as cold to account for glacial periods, for snow and ice can no

more than other things be made out of nothing, and every snowflake

implies an equal amount of aqueous vapour raised somewhere else by

evaporation. But if an abundant supply of liquid or gaseous water is

combined with cold sufficient to condense it into the solid form, it

becomes fixed, and if the summer heat is insufficient to melt the

excess of snow, it necessarily accumulates. The growth of glaciers,

follows as an inevitable consequence. The snow is converted into

ice by pressure and by alternate freezing and melting, and this

grows year by year, until an equilibrium is established by the ice

pushing down glaciers into lower levels, where the melting is more

rapid, or into the sea, where the front is floated off in icebergs,

and drifts into lower latitudes. The process is the same as that

by which the rainfall on high levels is drained off by rivers into

the sea, so that an equilibrium is established between waste and

supply. And it is to be remarked that the glacier, though composed

of solid ice, behaves exactly like a river, or rather like a river

of some viscous fluid like pitch or treacle. Its size depends on the

magnitude of the reservoir or area drained by it; it conforms to the

configuration of the valley by which it descends and the obstacles

which it encounters; it flows rapidly, and with a broken current,

through narrow gorges and down steep inclines; slowly and tranquilly

over wide and level areas; its velocity is greatest at the surface

and in the middle where friction is least, slowest at the bottom and

sides where it is greatest. In short a glacier is simply a solid

and slowly-flowing river, discharging an excess of solid ice to the

lower level from which it came, just as a liquid river does with the

rainfall of warmer regions. The cause of this tendency of solid and

brittle ice to flow like a viscous fluid is not quite understood,

though recent researches, especially those of Tyndall, have thrown

a good deal of light upon it; but all glacialists are agreed on

the _fact_ that it does so, and we can argue from it with great

confidence as to the conditions under which glaciation has acted in

the past and is now acting.

Thus even if Namsen had never crossed Greenland, or Ross had never

discovered Mounts Erebus and Terror, we might have inferred with

certainty the existence of enormous ice-caps, implying continental

masses of elevated land, in both the Arctic and Antarctic circles,

from the number and size of the icebergs floated off into the

Northern Atlantic and Southern Pacific Oceans. Icebergs are

frequently met with in the latter down to 50° south latitude, or

even lower, of a mile in length and 500 feet high above the sea;

and in some instances icebergs three miles long and 1000 feet high

have been recorded. As upwards of eight feet of ice must be under

water for every foot that floats above it, some of these icebergs

must be considerably over a mile in thickness, which implies that

there must be land ice towards the south pole so thick that it is,

in places, over 5000 feet in thickness at its outer margin. It has

been estimated from the great size and abundance of these icebergs,

that in the interior of the great Antarctic continent the ice may

be twenty miles or more thick, and in Greenland the great interior

ice-cap rises in a dome to at least 9000 or 10,000 feet above the

sea-level, a great part of which is solid ice, while during the great

glacial period it was certainly very much thicker.

As a first step therefore towards a solution of the problem of the

glacial period we may start with the axiom that it requires abundant

evaporation, combined with a temperature low enough to precipitate

an excess of that evaporation in the solid form. This does not

necessarily imply any great and permanent refrigeration of the whole

earth, for although this would give the cold it would not give the

evaporation, and would tend rather to extend the conditions of

Siberia than those of Greenland. Longer and colder winters with

shorter and hotter summers would seem more adapted to the growth of

glaciers.

But for a more exact investigation our next step must be to inquire

what are the causes which may have produced these postulates of a

glacial period, lower temperature with larger evaporation. They may

be classed under two heads.

1st. Geographical causes, arising from latitude, aërial and oceanic

currents, and a different distribution of sea and land.

2nd. Cosmic causes, such as variations of solar and terrestrial heat,

passage through colder regions of space, the position of the poles,

precession, and the eccentricity of the earth's orbit.

All these have had supporters in their time, but the result of

the latest science has been to leave only two seriously in the

field--Lyell's theory of a different distribution and elevation

of sea and land, carrying with it changes in aërial and oceanic

currents; and Croll's theory of the effects of precession combined

with high eccentricity of the earth's orbit.

Thus, of the geographical causes, latitude is no doubt an important

factor in determining temperature, but it cannot of itself be the

cause of the glacial periods, for it has remained unchanged through

all the vicissitudes of heat and cold in geological times. The

latitude of Greenland and Spitzbergen is presumably the same now as

it was in the Miocene period, when they were the seat of a luxuriant

temperate vegetation; and at the present day we have only to follow

the isothermal lines to see to what a great extent climate in the

same latitudes is modified by other influences, such as the Gulf

Stream.

Of cosmic causes, the progressive cooling of the earth naturally

presents itself, at the first blush, as sufficient to account for the

glacial period. But although this has doubtless been an all-important

factor in pregeological times, in fashioning our planet from glowing

vapour into a habitable earth, it is no longer operative as an

immediate cause of vicissitudes of temperature. It is enough to say

that if it were, the cooling ought to be progressive, and having

once got into a glacial period we never ought to have got out of

it. But we clearly have recovered from the paroxysms of cold, both

of the first and second great glaciations of the recent period; and

according to most geologists, from the immensely earlier ones of the

Permian and Carboniferous, and perhaps of the Cambrian ages. As far

as it acts at all on surface temperature, the secular cooling of the

earth only acts indirectly by causing elevations and depressions of

the outer crust, and crumpling it into wrinkles, which originate

mountain chains, as the nucleus contracts, and thus affecting

geographical conditions.

The same objection applies with equal force to the theory that the

glacial period was caused by the sun giving out less heat owing to

its cooling by radiation. Here also it is obvious that if a glacial

period were once established from such a cause it ought never to

recover, but progress from bad to worse. We ought also, in this case,

to have had a uniform progressive refrigeration from the beginning

of geological time down to the present day, which has certainly not

been the case. On the contrary, geologists are generally agreed that

there are unmistakable traces of at least two glacial periods in the

Carboniferous and Permian ages, and the earliest Eocene was certainly

cooler than its later stages, as shown by their flora.

The conjecture that the sun is a variable star is also negatived

by the consideration that in this case there ought to have been

periodical variations in the earth's temperature, and hot and cold

climates recurring at regular intervals throughout geological time,

which has certainly not been the case.

Again, the passage of the solar system through cold regions of

space has been suggested, but it is a mere conjecture, unsupported

by a particle of evidence, and opposed to all we know of the laws

of heat, and of the constitution of the universe. It is hard to

conceive how hot regions can exist surrounded by cold ones, or _vice

versâ_, without walls of a non-conducting medium to separate them, or

that the faint heat from the fixed stars can ever have perceptibly

affected the temperature of space. And such a theory, if it were

possible, would fail to account for the frequent vicissitudes of hot

and cold at short intervals within the glacial period, and for the

great differences of temperature prevailing in the same latitudes.

An alteration in the position, of the poles has also been suggested,

but this also is clearly inadmissible. There is no evidence that the

present position has ever materially varied, and there is no known

law that could cause such a variation. On the contrary, all the

elaborate mathematical calculations by which the motions of the sun,

moon, and planets are deduced from Newton's law of gravity, tend to

negative such a supposition.

And what is perhaps even more convincing to a nonmathematical mind,

the position of the poles implies the position of the equator, and

cannot change without a corresponding change in the earth's shape.

Now the earth is not a sphere, but an oblate spheroid, of almost

the exact shape which a fluid mass would take revolving about the

present axis. The centrifugal force arising from the greater velocity

of rotation in going from the poles to the equator would pile up

a protuberant belt where the velocity was greatest, and in point

of fact the earth's equatorial diameter is longer than the polar

diameter by about twenty-eight miles. Any displacement therefore

of the poles, which carried them away from their present position,

must displace the present equator to a corresponding extent. This

mass of twenty-eight miles in thickness of earth and ocean must

be thrown out of the old position, and driven to establish a new

equilibrium in a position many degrees north or south of it in order

to affect climates materially, submerging all existing lands, and

leaving, until removed by denudation, miles upon miles of solid earth

in unsymmetrical belts, like the moraines of retreating glaciers,

as the equator shifted into new positions. And all this must have

occurred, not once, but twice at least, and that with many minor

vicissitudes, within the narrow limit of the quaternary period. It is

unnecessary to say that nothing of the sort could by any possibility

have occurred. Some evidence has recently been adduced that some

very slight changes in latitude are going on at the observatories

of Dorpat and Greenwich, but if confirmed these can only be of

very minute amount, arising from slight changes in the position

of the earth's centre of gravity owing to partial elevations and

depressions, and could never have been sufficient to account for

great variations of climate.[11]

[11] The latest researches seem to show that these slight

variations in latitude do not exceed 2" or 3", and are

periodical, with a period of no longer than 300 to 310 days.

Neither could the precession of the equinoxes have been of itself

a principal cause, for here also the limit of time negatives the

supposition. This precessional circle carries the perihelion and

aphelion, and with it the seasons, completely round, and brings

them back to the old position, in about 21,000 years, and therefore

if glacial periods were occasioned by them, there ought to be

alternations from _maximum_ of cold to _maximum_ of warmth in each

hemisphere every 10,500 years. But this has certainly not been the

case even in recent times, and still less if we go back to the

quaternary, tertiary, and earlier geological periods.

In fact it is only when combined with periods of high eccentricity

of the earth's orbit, according to Croll's theory, that precession

can pretend to have any claim to be an important factor in the

production of glacial periods. And even then the question is not of

its being the sole or principal cause, but only whether it has had

such a perceptible auxiliary effect on other more powerful causes,

as may enable us to use it as a chronometer in assigning approximate

dates for some of the more important phenomena of the long and varied

period between the close of the Tertiary and the establishment of the

Recent period.

As man certainly existed throughout the whole of this period,

the possibility of finding such a chronometer becomes intensely

interesting, and I proceed to discuss the latest state of scientific

opinion respecting it. But as Croll's theory if a real is clearly

only an auxiliary cause, I will, in the first instance, point out

what are the certain and admitted causes which account for variations

of temperature irrespective of latitude.

They may be summed up, in Lyell's words, as different combinations

of sea and land, for on these depend the secondary conditions which

affect temperature. Thus elevation of land is as certain a cause

of cold as high latitude, and even Kilimanjaro, under the equator,

retains patches of unmelted snow throughout the year. It is estimated

that a rise of 1000 feet in height is about equivalent to a fall of

3° F. in mean annual temperature, and that the line of perpetual

snow is, on the average, a little higher than the line where this

mean annual temperature is at 32° F., or freezing-point. If there

is any mass of land so high as to be below this temperature, snow

accumulates and forms glaciers, which descend some 4000 feet below

the snow-line before the excess of ice pushing down is melted off by

the summer heat unless it has been previously floated off in icebergs

at a higher level. Now the mean temperature of the north of Scotland

at sea-level is about 46° F., so that an elevation of 8000 or 10,000

feet would bring a great part of it well above the snow-line, and

vast glaciers would inevitably accumulate, which would push down

through the principal valleys almost to the sea-level; a state of

things which actually exists in New Zealand, where glaciers from the

Southern Alps at about this elevation descend, in some instances to

within 700 feet of the sea-level, in the latitude of Devonshire.

But a still more important factor of temperature is found in aërial

and oceanic currents, which again, to a great extent, are a product

of the configuration of sea and land. The most familiar instance

is that of the Gulf Stream, which raises the temperature of Western

Europe some 10°, and in Norway as much as 15° F., above that due to

latitude, and which prevails on the other side of the Atlantic. The

northern extremity of the British Islands in Shetland is on the same

parallel of latitude as the southern extremity of Greenland, Cape

Farewell. One is buried under perpetual ice, in the other there is so

little frost in winter that skating is an unknown art.

What is the reason of this? We must go to the tropics to find it. A

vast mass of vapour is raised by the sun's heat from the oceans near

the equator, which being lighter rises and overflows, the trade winds

rushing in from the north to supply its place, and being deflected

to the west by the earth's rotation. This prevalence of easterly

surface winds sweeps the waters of the Atlantic to the west, where

they are intercepted by South America, turned northwards into the

Gulf of Mexico, where they circle round under a tropical sun and

become greatly heated, and finally run out through the Straits of

Florida with a rapid current, and spread a surface return current

eastwards over the Northern Atlantic. The shores of North-west Europe

are thus in the position of a house warmed by hot-water pipes, while

their neighbours over the way in North-eastern America have no such

apparatus.

This oceanic circuit of warm water has a counterpart in the aërial

circuit of heated air. The vapour which rose in the tropics

overflows, and as it cools and gets beyond the region of the trade

winds, descends mainly over the Northern Atlantic, carrying with it

its greater velocity of rotation, and so causing westerly winds,

which reach our shores after blowing over a wide expanse of ocean

heated by the Gulf Stream, thus bringing us warmth and wet, while the

corresponding counter-currents which blow over continental Europe and

Asia from the north-east bring cold and drought. The extreme effects

of this may be seen by comparing the Black Sea at Odessa, where ice

often stops navigation, with the North Sea at the Lafoden islands,

where the cod-fishing is carried on in open boats in the middle of

winter. We in England are in the happy position where on the whole

the mild and genial west winds prevail, though not exclusively, so as

to give us the drenching rains of Western Ireland and Scotland, or to

prevent spells of a continental climate which give us bracing frosts

in winter, and alternations of cold and heat in summer.

If we turn from these temperate regions to those in which exactly

opposite conditions prevail, we find them still in the icy chains of

a glacial period. Greenland, for instance, which is a typical case,

shows us what happens when a continental mass of land stands at a

high elevation in high latitudes with no Gulf Stream, but instead

of it cold currents from a Polar ocean, and seas around it frozen

or covered with icebergs for nine months out of the year. We have a

dome of solid ice piled up to the height of 9000 feet or upwards,

and sending millions upon millions of tons of glaciers down to the

sea to be floated off as icebergs. The only trace we can see here of

the old great glacial period is that these conditions were formerly

more intense. Thus the glaciation of some of the mountain sides and

islands off the coast of Greenland seem to show that the ice formerly

stood 2000 or 3000 feet higher than at present, a result which

would be attained if the whole continental mass, which is now slowly

subsiding, had then been elevated to that extent.

The southern hemisphere affords a still more striking example of this

on a larger scale, for we have there, in all probability, higher land

in higher latitudes, surrounded by frozen seas, and washed by cold

currents. I pass from this however, as beyond these general facts the

special conditions of the Antarctic Circle are not known to us like

those of Greenland.

From the above facts we are very safe in drawing the conclusion that

during the great quaternary glacial period the conditions which

now cause glaciation must have existed in an aggravated degree,

and those which now give us temperate climates in regions once

glaciated must have disappeared or been reversed. On the other hand,

the warm climates which prevailed during the tertiary and other

geological epochs, and permitted a temperate flora to flourish as

far north as Grinnell Land and Spitzbergen, could only have occurred

under conditions exactly the reverse of those which produced the

cold. If high land in high latitudes is the principal cause of the

present glaciation of Greenland, still higher land must have been

so in causing the still greater glaciation of the former period.

Scandinavia, Laurentia, the British Islands, the Alps, Apennines,

Rocky Mountains, Sierra Nevada, and all great mountain ranges in the

northern hemisphere must have stood at greater elevations. There must

have been such an accumulation of ice and snow as to chill the air,

cause fogs, and prevent the summer heat of the sun from melting off

the water which fell in the solid form during winter; and on the

other hand, there must have been hot summers and great expanses of

ocean to the south to supply the abundant evaporation which became

condensed by contact with the chilly mountains and uplands of the

north.

One supposition is that the Isthmus of Panama was then submerged, so

that the Gulf Stream ran into the Pacific. But this wants geological

confirmation, as the Isthmus shows no sign of such recent marine

formations as must have been deposited if it had been submerged to a

sufficient depth to let the Gulf Stream escape, and the extension of

the ice-cap in North America to much lower latitudes than in Europe,

points rather to the conclusion that the Gulf Stream must have run

very much in its present course.

The only geological evidence bearing on this question is the

recent discovery of deep oceanic deposits such as the Globigerena

ooze, above tertiary deposits in Barbadoes and Jamaica, leading to

the inference that the whole West Indian area was a deep sea in

comparatively modern times. This no doubt might affect both the

temperature and the velocity of the Gulf Stream to a considerable

extent.

But the geological evidence is much more conclusive for the greater

elevation of the land during the periods of greater glaciation as

well as for its depression during the inter-glacial period. American

geologists estimate that a large part of Eastern Canada with adjacent

regions must have been at least 2000, and may have been as much as

3000 feet above its present level during the first great glaciation;

while the Champlain marine beds show that it was some hundreds of

feet below the present, sea-level during part of the inter-glacial

period. Scandinavia stood at least 2000 feet higher than at present

during the climax of the glacial period as proved by the depths of

the fiords, and afterwards 500 or 600 lower as proved by the raised

beaches. In Great Britain and Ireland we have conclusive evidence

both of higher elevation, and of depression of at least 1300 feet,

and probably more than 2000 feet below the present sea-level, as

proved by the marine shells on the top of Moel-Tryfen.

But these elevations and depressions are small in amount compared

with the mountain building which is known to have occurred in Asia in

comparatively recent geological times. Here the Himalayas, stretching

for 1500 miles from east to west, and rising to heights of from

20,000 to 29,000 feet above the sea, have been formed in great part

during this period. Within the same period the great table-lands

of Thibet and Central Asia have been uplifted, and the Asian

Mediterranean Sea, of which the Black Sea, the Caspian, the Salt

deserts and Lake Balkash are the remnants, has been converted into

dry land. Movements of this magnitude, of which there are many other

examples, may well account for great changes in isothermal lines and

climates.

The complete removal of the conditions which produced the glacial

period might go far to account for the preceding tertiary period.

We have only to suppose a different configuration of sea and land;

nothing but low lands and islands in high latitudes; free access for

warm oceanic currents like the Gulf Stream into the limited area

of the Polar basin; no great continents or lofty mountain ranges

to drain the return trade winds of their moisture; in short, all

the conditions of a mild and moist insular climate, as opposed to

those of a continental one, to understand how forests of temperate

trees might flourish as far north as Greenland and Spitzbergen. And

the geological evidence which, as we have seen, shows that great

elevation of land in the northern hemisphere did in fact inaugurate

the glacial period, favours the conclusion that the reverse

conditions actually prevailed during the tertiary and preceding

epochs.

The presence of the Nummulitic and other marine Eocene and Miocene

formations over such extensive areas, and at such great elevations,

is a conclusive proof that a great part of our existing continents

were then at the bottom of deep oceans. The Alps were certainly

10,000 feet lower than their present level, and the Himalayas more

so; and when this was the case a great part of Europe and Asia must

have been sea, in which only a few of the highest peaks and elevated

plateaux stood up as islands. The Pacific and Indian Oceans as well

as the Atlantic might then have poured their Gulf Streams into the

Polar basin, and prevalent southerly and westerly winds, blowing

over wide expanses of water, have deposited their vapour in genial

showers instead of in solid snow. The effect of such geographical

conditions in producing both heat and cold is admirably worked out

by Wallace in his _Island Life_, and few who read it can doubt

that Lyell was right in saying that they have been the principal

causes of the vicissitudes of climate. And here I may say a word to

express my admiration of the innate sagacity with which Lyell, many

years ago, and with comparatively few facts to work upon, sketched

out the leading lines of geology, which have been confirmed by

subsequent research. Details may have been corrected or added, but

his main theories have stood the fullest test of the survival of the

fittest. His law of the uniformity of natural causes, continued for

long intervals of time, holds the field unchallenged. These causes

may have operated a little more quickly or slowly in former ages

than at present, but they have been of the same order. The waste of

continents, instead, of averaging one foot in 4000 years, may have

averaged ten or twenty feet during certain periods, and certain

portions of the earth's crust may have been elevated or depressed at

a quicker rate than is now going on in Scandinavia; but no one any

longer believes in paroxysms throwing up mountain chains or sinking

continents below the ocean at a single blow.

In like manner later geologists have corrected details in the

distribution of land and sea suggested by Lyell to account for the

glacial period, but his main law has only received confirmation--viz.

that this distribution, and especially high land in high latitudes,

has been the principal cause of such periods.

At the same time there is a pretty general consensus of the best and

latest geologists, that, as Lyell himself suggested, elevation and

depression and other geographical changes, though the principal, are

not the sole causes of the glacial period. The main argument is, that

the phases of this period, though not exactly simultaneous over the

whole world, are too nearly so to be due to mere local movements,

and require the intervention of some general cosmic cause. We have

already seen that of such causes there is none which appears feasible

except Croll's theory of the effects of precession combined with high

eccentricity.

Let us consider what this theory really asserts. If the earth were

a perfect sphere, its orbit round the sun a perfect circle, and the

equator coincided with the ecliptic, there would be no seasons. The

four quarters of the year would each receive the same quantity of

solar heat and light, and the days and nights would be always equal.

But the inclination of the equator to the ecliptic, that is, of the

earth's plane of daily rotation to that of its annual revolution,

necessitates seasons. Each pole must be alternately turned to and

away from the sun every year. Each hemisphere, therefore, must

have alternately its spring, summer, autumn, and winter. But if

the earth's orbit were exactly circular, these seasons would be of

equal duration, and the distance from the sun no greater in one than

in another. But the earth's orbit is not circular, but elliptic,

and the eccentricity, or deviation of the oval from the circular

form, varies considerably over very long periods, though always

coming back to the amount from which it started. These variations

are due to perturbations from the other bodies of the solar system

acting according to the law of Newton's gravitation, and therefore

calculable.

Again, the earth is not a perfect sphere, but a spheroid, and

there is a factor called precession, due to the attraction on the

protuberant mass at and towards the equator. The effect of this is,

that instead of the earth's axis pointing uniformly towards the same

celestial pole, it describes a small circle round it. This circle is

completed in about 21,000 years, so that if the earth is nearest to

the sun when the North Pole is turned away from it, and it is winter

in the northern hemisphere, as is now the case, in 10,500 years the

conditions will be reversed, and the southern hemisphere will be in

perihelion, or nearest the sun, when its pole points away from it.

And as the perihelion portion of the earth's orbit is, owing to its

eccentricity, shorter and more quickly traversed than the aphelion

portion, this means practically that winters will be shorter than

summers in the hemisphere which precession favours, and longer in

that to which it is adverse.

As precession now favours the northern hemisphere, which is warmer

than the southern in corresponding latitudes, it might be thought at

first sight that this was the cause of the glacial period. But it is

evident that this is not the case, for the precessional revolutions

come round far too rapidly, and it is impossible to suppose that

there have been glacial and genial periods alternating every 10,500

years, with all the inevitable changes of seas and lands, and of

fauna and flora, accompanying each alternation throughout the whole

of geological time. In fact, it is abundantly evident, on historical

evidence alone, that there has been no approach to any such changes

during the last 10,500 years, which carries us back to a period when

our northern summers were short and our winters long.

But Croll's theory brings in the secular variation of the

eccentricity, and contends that although precession may have little

or no effect while the earth's orbit is nearly circular, as it is

now, it must have a considerable effect when the orbit flattens

out, so that the distances from the sun and the durations of summer

and winter become exaggerated. Croll calculated the periods when

such _maxima_ and _minima_ of eccentricity occurred for several

revolutions back from the formula of the great astronomer Leverrier,

and found that going back for the last 260,000 years there had been

two _maxima_ of high eccentricity, one 100,000 years, and the other,

and more intense, 210,000 years ago, with corresponding _minima_ of

low eccentricity between, which corresponded remarkably well with the

refrigeration commencing in the Pliocene, culminating towards its

close or in the early Quaternary, subsiding into a long inter-glacial

period, rising again in the later Quaternary to a second glacial

_maximum_ a little less intense than the first, and finally gradually

subsiding into the low eccentricity and temperate climates of more

recent times; especially as the geological evidence shows many minor

oscillations of heat and cold and advances and retreats of glaciers

during each phase of these periods, such as must have occurred from

the shorter recurrent effects of precession according to Croll's

theory.

Croll's calculations show that, at the period of _maximum_

eccentricity 210,000 years ago, the earth would have been in

mid-winter 8,736,420 miles further from the sun than it is now, and

the winter half of the year nearly twenty-eight days longer than the

summer half, instead of being six days shorter as at present. It

appears, moreover, from a volume just published, _On the Astronomical

Causes of an Ice Age_, by Sir R. Ball, one of the highest authorities

on mathematics and astronomy, that Croll had understated his case.

Ball says that "Croll, misled by a statement of Herschell's, had

assumed the number of units of heat received from the sun, in a

hemisphere of the earth, as equal in summer and winter. But in

reality, of 100 such units, 63 are received in summer and only 37

in winter. As the maximum of eccentricity which is possible would

produce an inequality between summer and winter of 33 days, they

had the following possible conditions in a hemisphere--summer 199

days and winter 166 days, or summer 166 days and winter 199 days.

In each case it must be borne in mind that 63 heat units arrived in

summer and 37 in winter. If the summer were a long one and the winter

short, then the allotment of heat between the two seasons would be

fairly adjusted. The 63 units were distributed over 199 days and the

37 units over 166 days, and a general inter-glacial state was the

result on the hemisphere. If, however, a torrent of heat represented

by 63 units was poured in during a brief summer of 166 days, whilst,

the balance of 37 units is made to stretch itself over 199 days, a

brief, intensely hot summer would be followed by a very long and cold

winter, and as this condition lasted for many centuries, it seemed

sufficient to produce a glacial epoch."

It would be going, too far, however, to assume that these conditions

necessarily produced glacial periods whenever they occurred, and

Ball himself points out that even on astronomical grounds, several

conditions must concur before high eccentricity alone would affect

climate. But even with this reservation the same objection applies

to assigning, this as the sole or principal cause of Ice Ages, as

to precession alone, viz. that periods of high eccentricity occur

too frequently to allow us to suppose that every such period in the

past has had its corresponding glacial period. There was a _maximum_

phase of eccentricity 700,000 years ago, even higher than that of

210,000 years, and there must have been at least two or three such

_maxima_ within each of the twenty-eight geological ages. But there

are only two or three traces of glacial periods in past epochs on

which geologists can rely with confidence, as proving extensive

ice-action--one in the Permian, the other in the Carboniferous age.

There are a few other instances which look like glacial action, as

the conglomerate of the Superga at Turin, the Flysch of Switzerland,

the great conglomerate at the base of the Devonian; and Professor

Geikie thinks that the oldest Cambrian rocks in the West Highlands

have been rounded and smoothed by ice before the Silurian strata were

deposited on them. But even if these were authenticated and proved to

be due to general and not merely local causes, they would not supply

anything like the number of glacial periods required by Croll's

theory. Croll attempts to meet this by the extensive denudation which

has repeatedly carried away such large portions of land surface;

but this scarcely explains the absence of the boulders of hard

rocks, which accompany every moraine and iceberg; and still less the

continuance of the same fauna and flora throughout whole geological

periods with little or no change. We have no such abrupt changes as

during the last glacial period, when at one time the canary laurel

flourished in Central France, while at another the reindeer moss and

Arctic willow extended to the Pyrenees, both occurring within what

may be called a short time, geologically speaking. On the contrary,

there seems to have been no material changes in the flora throughout

very long geological periods such as that of the Coal Measures.

The only real answer to this objection is that the question is,

not whether Croll's theory is the sole or even the principal cause

of glacial periods, or able to influence them materially if the

geographical conditions favour genial climates; but whether it has

not a co-operating effect, when these conditions are such as to

produce glaciation. It seems difficult to suppose that such contrasts

of conditions as are pointed out by Sir R. Ball can have had no

perceptible effect on climates; or that such close coincidences as

are shown between the astronomical theory and geological facts,

during the last glacial period, can be due to mere accident.

Geology shows six phases of this period:--(1) a refrigeration

coming on in the Pliocene; (2) its culmination in a first and most

intense _maximum_; (3) a gradual return to a milder inter-glacial

period; (4) a second refrigeration; (5) its culmination in a second

_maximum_; (6) a second return to genial conditions, such as still

prevail. Croll's theory shows six astronomical phases, corresponding

to these six geological phases. Geology shows that each of its six

phases involves several minor alternations of hot and cold; Croll

shows that this must have been the case owing to the effects of the

shorter cycles of precession, occurring during the long cycles of

variations in eccentricity. Geology tells us that cold alone would

not account for a glacial period; we must have heat to supply the

evaporation which is condensed by the cold; Croll shows that with

high eccentricity cold and long winters must have been accompanied

by short and hot summers. And Sir R. Ball's recent calculations show

that the argument is really very much stronger than Croll puts it.

The duration of each of the phases of Croll's theory corresponds

also, on the whole, remarkably well with that required for each

phase of the geological record. They would average about 40,000

years each for Croll's phases, and a less time can hardly be allowed

for the immense amount of geological work in the way of denudation

and deposition, elevation and depression, and changes of fauna

and flora which have occurred since the commencement of the great

refrigeration in the late Pliocene. In fact the only reasonable doubt

seems to be whether Croll's times are sufficient, and whether, as

Lyell was inclined to think, the first and greatest glaciation must

not be carried back to the extreme period of high eccentricity which

occurred about 700,000 years ago.

Unless we are prepared to ignore all these considerations and

deny that Croll's theory, as amended by Sir R. Ball, has had any

appreciable effect on the conditions of the glacial period, it

follows with mathematical certainty, that this period, taking it

from the commencement of the great refrigeration in the Pliocene to

its final disappearance in the Recent, must have lasted for about

200,000 years. And as man clearly existed in the pre-glacial period,

and was already widely spread and in considerable numbers in the

early glacial, 250,000 years may be taken as an approximation to the

_minimum_ duration of the existence of the human race on the earth.

To this must be added an indefinitely long period beyond, unless we

are prepared to disprove the apparently excessively strong evidence

for its existence in the Pliocene and even in the Miocene periods;

evidence which has been rapidly accumulating of late years; and to

which, as far as I know, there has been no serious and unbiassed

attempt at scientific refutation; and to which confirmation is given

by the undoubted fact that the Dryopithecus, the Hylobates, and other

quadrumana, closely resembling man in physical structure, already

existed in the Miocene, and, if Professor Ameghino's discoveries

referred to at p. 264 are confirmed, in the vastly more remote period

of the early Eocene.

CHAPTER X.

QUATERNARY MAN.

No longer doubted--Men not only existed, but in numbers and

widely spread--Palæolithic Implements of similar Type found

everywhere--Progress shown--Tests of Antiquity--Position of

Strata--Fauna--Oldest Types--Mixed Northern and Southern

Species--Reindeer Period--Correspondence of Human Remains

with these Three Periods--Advance of Civilization--Clothing

and Barbed Arrows--Drawing and Sculpture--Passage into

Neolithic and Recent Periods--Corresponding Progress of

Physical Man--Distinct Races--How tested--Tests applied to

Historical, Neolithic, and Palæolithic Man--Long Heads and

Broad Heads--Aryan Controversy--Primitive European Types--Canon

Taylor--Huxley--Preservation of Human Remains depends mainly on

Burials--About forty Skulls and Skeletons known from Quaternary

Times--Summary of Results--Quatrefages and Hamy--Races

of Canstadt--Cro-Magnon--Furfooz--Truchere--Skeletons of

Neanderthal and Spy--Canstadt Type oldest--Cro-Magnon Type

next--Skeleton of Cro-Magnon--Broad-headed and Short Race

resembling Lapps--American Type--No Evidence from Asia, Africa,

India, Polynesia, and Australia--Negroes, Negrillos, and

Negritos--Summary of Results.

The time is past when it is necessary to go into any lengthened

argument to prove that man has existed throughout the Quaternary

period. Less than half a century has elapsed since the confirmation

of Boucher-de-Perthes' discovery of palæolithic implements in the old

gravels of the Somme, and yet the proofs have multiplied to such an

extent that they are now reckoned, not by scores or hundreds, but by

tens of thousands. They have been found not in one locality or in one

formation only, but in all the deposits of the Quaternary age, from

the earliest to the latest, and in association with all the phases of

the Quaternary period, from the extinct mammoth, woolly rhinoceros,

and cave-bear, to the reindeer, horse, ox, and other existing

animals. No geologist or palæontologist, who approaches the subject

with anything like competent knowledge, and without theological or

other prepossessions, doubts that man is as much a characteristic

member of the Quaternary fauna as any of these extinct or existing

animals, and that reasonable doubt only begins when we pass from the

Quaternary into the Tertiary ages. I will content myself, therefore,

instead of going over old ground and proving facts which are no

longer disputed, with showing what bearing they have on the question

of human origins.

[Illustration: PALÆOLITHIC CELT (type of St. Acheul).

From Quaternary deposits of the Nerbudda, India.]

[Illustration: PALÆOLITHIC CELT IN ARGILLITE.

From the Delaware, United States (Abbott).]

The first remarkable fact to note is, that at this remote period man

not only existed, but existed in considerable numbers, and already

widely spread over nearly the whole surface of the habitable earth.

Implements and weapons of the palæolithic type, such as celts or

hatchets, lance and arrow-heads, knives, borers and scrapers of

flint, or if that be wanting of some hard stone of the district,

fashioned entirely by chipping without any grinding or polishing,

have been found in the sands and gravels of most of the rivers of

Southern England, France, Belgium and Germany, of the Tagus and

Manzanares in Spain, and the Tiber in Italy. Still more numerously

also in the caves and glacial drifts of these and other European

countries. Nor are they confined to Europe. Stone implements of the

same type have been found in Algeria, Morocco, and Egypt, and in

Natal and South Africa. Also in Greece, Syria, Palestine, Hindostan,

and as far east as China and Japan, while in the New World they have

been found in Maryland, Ohio, California, and other States in North

America, and in Brazil, and the Argentine pampas in the South. And

this has been the result of the explorations of little more than

thirty years, prior to which the coexistence of man with the extinct

animals was almost universally denied; and of explorations which

except in a few European countries have been very partial.

[Illustration: PALÆOLITHIC FLINT CELT (type of St. Acheul).

From Algeria (Lubbock).]

[Illustration: PALÆOLITHIC CELT OF QUARTZITE FROM NATAL, SOUTH

AFRICA.

(_Quatrefages._)]

In fact the area over which these evidences of man's existence

have been found may be best defined by the negative, where they

have not been found, as there is every probability that it will

eventually be proved that, with a few exceptions, wherever man could

have existed during the Quaternary period, there he did exist. The

northern portions of Europe which were buried under ice-caps are

the only countries where considerable search has failed to discover

palæolithic implements, while nearly all Asia, Africa, and America,

and vast extents of desert and forests remain unexplored.

The next point to observe is, that throughout the whole of the

Quaternary period there has been a constant progression of human

intelligence upwards. Any theory of human origins which says that man

has fallen and not risen is demonstrably false. How do we know this?

The time scale of the Quaternary as of other geological periods is

determined partly by the superposition of strata, and partly by the

changes of fauna. In the case of existing rivers which have excavated

their present valleys in the course of ages, it is evident that the

highest deposits are the oldest. If the Somme, Seine, or Thames left

remains of their terraces and patches of their silts and gravels at

heights 100 feet or more above their present level, it is because

they began to run at these higher levels, and gradually worked their

way downwards, leaving traces of their floods ever lower and lower.

In the case of deposits in caves or in still water, or where glacial

moraines and _débris_ are superimposed on one another, the case is

reversed, and the lowest are the oldest and the highest the most

recent.

In like manner if the fauna has changed, the remains found in the

highest deposits of rivers and lowest, of caves will be the oldest,

and will become more modern as we descend in the one case or ascend

in the others.

This is practically confirmed by the coincidence of innumerable

observations. The oldest Quaternary fauna is characterized by a

preponderance of three species, the mammoth (Elephas primigenius),

the woolly rhinoceros (Rhinoceros tichorinus), and the cave-bear

(Ursus spelæus).

There are a few survivals from the Pliocene, as the gigantic elephant

(Elephas antiquus) and a few anticipations of later phases, as

the reindeer, horse, and ox, but the three mentioned are, with

palæolithic man, the most characteristic. Then comes a long period

when a strange mixture of northern and southern forms occurs. Side

by side with the remains of Arctic animals such as the mammoth, the

glutton, the musk ox, and the lemming, are found those of African

species adapted only for a warm climate, the lion, panther, hyena,

and above all the hippopotamus, not distinguishable from the existing

species, which could certainly not have lived in rivers that were

frozen in winter.

The intermixture is most difficult to account for. No doubt Africa

and Europe were then united, and the theory of migration is invoked.

The Arctic animals may, it is said, have moved south in winter and

the African animals north in summer, and this was doubtless the case

to some extent. But there are some facts which militate against

this theory; for instance, the hyena caves, which seem to show a

continuous occupation by the same African species for long periods.

Nor is it easy to conceive how the hippopotamus could have travelled

every summer from Africa to Yorkshire, and retreated every autumn

with the approach of frost. Such instances point rather to long

inter-glacial periods with vicissitudes of climate, enabling now a

northern, and now a southern fauna to inhabit permanently the same

region.

Be this as it may, the fact is certain that this strange intermixture

of northern and southern species is found in almost all the European

deposits of the Quaternary age, until towards its close with the

coming on of the second great glacial period, when the southern

forms disappear, and the reindeer, with an Arctic or boreal flora

and fauna, become preponderant, and extend themselves over Southern

France and Germany up to the Alps and Pyrenees.

The Quaternary period is therefore roughly divided by geologists into

three stages: 1st, that of the mammoth and cave-bear, there being

some difference of opinion as to which came first, though probably

they were simultaneous; 2nd, the middle stage of the mixed fauna;

3rd, the latest stage, that of the reindeer.

Now to these stages there is an exact correspondence in the character

of the human implements found in them. In the earliest, those of

the oldest deposits and of the oldest animals, we find the rudest

implements. They consist almost exclusively of native stones, chipped

roughly into a few primitive shapes: celts, which are merely lumps

of flint or other hard stone with a little chipping to supplement

natural fractures in bringing them to a point or edge, while the

butt-end is left rough to be grasped by the hand; scrapers with

a little chipping to an edge on one side; very rude arrow-heads

without the vestige of a barb or socket; and flakes struck off at

a blow, which may have served for knives. As we ascend to later

deposits we find these primitive types constantly improving. The

celts are chipped all over and the butt-ends adapted for haftings,

so also are the other implements and weapons, and the arrow-heads

by degrees acquire barbs. But the great advance occurs with the use

of bone, which seems to have been as important a civilizing agent

for palæolithic as metals were for neolithic man. This again seems

to have been due to the increasing preponderance of the reindeer,

whose horns afforded an abundant and easily manipulated material for

working into the desired forms by flint knives.

At any rate the fact is, that as we trace palæolithic man upwards

into the later half of the Quaternary period when the reindeer became

abundant, we find a notable advance of civilization. Needles appear,

showing that skins of animals were stitched together with sinews

to provide clothing. Barbed arrows and harpoons show that the arts

of war and of the chase had made a great advance on the primitive

unhafted celt. And finally we arrive at a time when certain tribes

showed not only an advance in the industrial arts, but a really

marvellous proficiency in the arts of sculpture and drawing. In the

later reindeer period, when herds of that animal and of the wild

horse and ox roamed over the plains of Southern France and Germany,

and when the mammoth and cave-bear, though not extinct, were becoming

scarce, tribes of palæolithic savages who lived in the caves and

rock shelters of the valleys of Southern France and Germany, and of

Switzerland and Belgium, drew pictures of their chases and of the

animals with which they were surrounded, with the point of a flint

on pieces of bone or of schist. They also carved bones into images

of these animals, to adorn the handles of their weapons or as idols

or amulets. Both drawings and sculptures are in many cases admirably

executed, so as to leave no doubt of the animal intended, especially

in the case of the wild animals, for the rare portraits of the human

figure are very inferior. Most of them represent the reindeer in

various attitudes, but the mammoth, the cave-bear, the wild horse,

the Bos primigenius, and others, are also represented with wonderful

fidelity.

With the close of the reindeer age we pass into the Recent period

and from palæolithic to neolithic man. Physically there is no

very decided break, and we cannot draw a hard-and-fast line where

one ends and the other begins. All we can say is, that there is

general evidence of constantly decreasing cold during the whole

post-glacial period, from the climax of the second great glaciation

until modern conditions of climate are fairly established, and the

existing fauna has completely superseded that of the Quaternary,

the older characteristic forms of which having either become

extinct or migrated. How does this affect the most characteristic

of all Quaternary forms, that of man? Can we trace an uninterrupted

succession from the earliest Quaternary to the latest modern times,

or is there a break between the Quaternary and Recent periods which

with our present knowledge cannot be bridged over? And did the

division of mankind into distinct and widely different races, which

is such a prominent feature at the present day and ever since the

commencement of history, exist in the case of the palæolithic man,

whose remains are so widespread?

These are questions which can only be answered by the evidence of

actual remains of the human body. Implements and weapons may have

altered gradually with the lapse of ages, and new forms may have

been introduced by commerce and conquest, without any fundamental

change in the race using them. Still less can language be appealed to

as a test of race, for experience shows how easily the language of

a superior race may be imposed on populations with which it has no

affinity in blood. To establish distinction of races we consult the

anthropologist rather than the geologist or philologist.

[Illustration: PORTRAIT OF MAMMOTH.

Drawn with a flint on a piece of Mammoth's ivory; from Cave of La

Madeleine, Dordogne, France.]

[Illustration: EARLIEST PORTRAIT OF A MAN WITH SERPENTS AND

HORSES' HEADS.

From Grotto of Les Eyzies. Reindeer Period.]

[Illustration: REINDEER FEEDING.

From Grotto of Thayngen, near Schaffhausen, Switzerland.]

On what are the distinctions of the human race founded? Mainly on

colour, stature, hair, and on the anatomical character of skulls and

skeletons. These are wonderfully persistent, and have been so since

historical times, intermediate characters only appearing where there

has been intercrossing between different races. But the primitive

types have continued unchanged, and no one has ever seen a white race

of Negroes, or a black one of Europeans. And this has certainly been

the case during the historical period, or for at least 7000 years,

for the paintings on old Egyptian tombs show us the types of the

Negro, the Libyan, the Syrian, and the Copt as distinct as at the

present day, and the Negroes especially, with their black colour,

long heads, projecting muzzles, and woolly hair growing in separate

tufts, might pass for typical photographs of the African Negro of the

nineteenth century.

Of these indications of race we cannot hope to meet with any of the

former class in Quaternary gravel or caves. We have to trust to the

anatomical character to be drawn from skulls and skeletons, of which

it may be inferred, as a matter of course, that they will be few and

scanty, and will become constantly fewer and more imperfect as we

ascend the stream of time to earlier periods. It must be remembered

also that even these scanty specimens of early man are confined

almost entirely to one comparatively small portion of the earth, that

of Europe, and that we have hardly a single palæolithic skull or

skeleton of the black, the yellow, the olive, the copper-coloured, or

other typical race into which the population of the earth is actually

divided.

We are confined therefore to Europe for anything like positive

evidence of these anatomical characters of prehistoric and primæval

man, and can only draw inferences from implements as to those of

other portions of the earth and other races. Fortunately these racial

characters are very persistent, especially those of the skull and

stature, and they exist in ample abundance throughout the historic,

prehistoric, and neolithic ages, to enable us to draw very certain

conclusions. Thus at present, and as far as we can see back with

certainty, the races which have inhabited Europe may be classified

under the heads, tall and short, long-headed and broad-headed, and

those of intermediate types, which latter may be dismissed for the

present, though constituting a majority of most modern countries,

as they are almost certainly not primitive, but the result of

intercrossing.

Colour, complexion, and hair are also very persistent, though, as we

have pointed out, we have no certain evidence by which to test them

beyond the historical period. But the form of skulls, jaws, teeth,

and other parts of the skeleton remain wonderfully constant in races

where there has been little or no intermixture.

The first great division is in the form of the skull. Comparing the

extreme breadth of the skull with its extreme length from front to

back, if the breadth does not exceed three-fourths or 75 per cent. of

the length, the skull is said to be dolicocephalic or long-headed; if

it equals or exceeds 83 per cent. it is called brachycephalic, _i.e._

short or broad-headed. Intermediate indices between 75 and 83 per

cent. are called sub-dolicocephalic, or sub-brachycephalic, according

as they approach one or the other of these extremes, but these are of

less importance, as they probably are the result of intercrossing.

The prognathism also of the jaws, the form of the eye-orbits and

nasal bones, the superciliary ridges, the proportion of the frontal

to the posterior regions of the skull, the stature and proportions of

the limbs, are also both characteristic and persistent features, and

correspond generally with the type of the skull.

The controversy as to the origin of the Aryans has led to a great

deal of argument as to these ethnological traits in prehistoric and

neolithic times, and the interesting volume of Canon Taylor's on the

_Origin of the Aryans_, and Professor Huxley's article on the same

subject in the _Nineteenth Century_ for November 1890, give a summary

of the latest researches on the subject. We shall have to refer to

these more fully in discussing the question as to the place or places

of human origins; but for the present it is sufficient to state the

general result at which the latest science has arrived.

The theory of a common Asiatic centre from which all the races of

mankind have migrated is given up as unsupported by the slightest

vestige of evidence. When we first know anything of the Aryan and

other European races, we find them occupying substantially very much

the same regions as at present. There are four distinct European

types, two tall and two short, two long-headed and two broad-headed.

Of these two were fair, and two dark, and one, apparently the oldest

in Western Europe and in the Mediterranean region, and probably

represented by the Iberians, and now by the Spanish Basques, was

short, dark, and long-headed; a second short, dark, and broad-headed,

who are probably represented by the ancient Ligurians, and survive

now in the Auvergnats and Savoyards; a third, tall, fair, and

long-headed, whose original seats were in the regions of the Baltic

and North Sea, and who were always an energetic and conquering race;

and the fourth, like the third, tall and fair, but with broad heads,

and possibly not a primitive race, but the result of some very

ancient intermixture of the third or Northern type with some of the

broad-headed races.

Now as far back as frequent human remains enable us to form some

satisfactory conclusion, that is up to the early neolithic period,

we find similar race-types already existing, and to a considerable

extent in the same localities. In modern and historical times we

find, according to Canon Taylor, "all the anthropological tests

agreeing in exhibiting two extreme types--the African, with long

heads, long eye-orbits, and flat hair; and the Mongolian, with

round heads, round orbits, and round hair. The European type is

intermediate--the head, orbits, and sections of hair are oval. In the

east of Europe we find an approximation to the Asiatic type; in the

south of Europe to the African."

More specifically, we find in Europe the four races mentioned above

of tall and short long-heads, and tall and short broad-heads. The

question is, how far back can any of these races be identified?

The preservation of human remains depends mainly on the practice of

burying the dead. Until the corpse is placed in a tomb protected by

a stone coffin or dolmen, or in a grave dug in a cave, or otherwise

sheltered from rains, floods, and wild beasts, the chances of its

preservation are few and far between. Now it is not until the

neolithic period that the custom of burying the dead became general,

and even then it was not universal, and in many nations even in

historical times corpses were burnt, not buried. It was connected

doubtless with ideas of a future existence, which either required

troublesome ghosts to be put securely out of the way, or to retain

a shadowy existence by some mysterious connection with the body

which had once served them for a habitation. Such ideas, however,

only come with some advance of civilization, and it is questionable

whether in palæolithic times the human animal had any more notion of

preserving the body after death than the other animals by which he

was surrounded.

This neolithic habit moreover of burying, though it preserves many

relics of its own time, increases the difficulty when we come to

deal with those of an earlier age. A great many caves which had been

inhabited by palæolithic man were selected as fitting spots for the

graves of their neolithic successors, and thus the remains of the two

periods became intermixed. It is never safe to rely on the antiquity

of skulls and skeletons found in association with palæolithic

implements and extinct animals, unless the exploration has been made

with the greatest care by some well-known scientific observer, or the

circumstances of the case are such as to preclude the possibility of

later interments. Thus in the famous cavern of Aurignac there is no

doubt that it had been long a palæolithic station, and that many of

the human remains date back to this period; but whether the fourteen

skeletons which were found in it, and lost owing to the pietistic

zeal of the Mayor who directed their burial, were really palæolithic,

is a disputed point, or rather the better opinion is that they were

part of a secondary neolithic interment.

But to return to undoubted neolithic skulls, we have very clear

evidence that the four distinct European races already existed. Thus

in Britain we have two distinct forms of barrows or burial tombs, one

long, the other round, and it has become proverbial that long skulls

go with long barrows, and round skulls with round barrows. The long

barrows are the oldest, and belong entirely to the stone age, no

trace of metal, according to Canon Greenwell, having ever been found

in them. The skulls and skeletons are those of a long-headed, short,

and feeble race, who may be identified with the Iberians; while

the round barrows contain bronze and finally iron, and the people

buried in them were the tall, fair, round-headed Gauls or Celts of

early history, or intermediate types between these and the older

race. Later came in the tall, fair, and long-headed Anglo-Saxon and

Scandinavian races, so that we have three out of the four European

types clearly defined in the British islands and traceable in their

descendants of the present day. But when we attempt to go beyond

the Iberians of the neolithic age in Britain, we are completely

at fault. We have abundant remains of palæolithic implements, but

scarcely a single undoubted specimen of a palæolithic skeleton, and

it is impossible to say whether the men who feasted on the mammoth

and rhinoceros in Kent's cavern, or who left their rude implements

in the high-level gravel of the chalk downs, were tall or short,

long-headed or round-headed. On the contrary, there seems a great

hiatus between the neolithic and the palæolithic periods, and, as

Geikie has shown, this appears to be the case not in England only but

in a great part of Europe. It would almost seem as if the old era had

disappeared with the last glacial period, and a completely new one

had been introduced. But although the skulls and bones of palæolithic

races are wanting in Britain and scarce everywhere, enough of them

have been found in other European countries to enable anthropologists

not merely to say that different races already existed at this

immensely remote period, but to classify them by their types, and

see how far these correspond with those of later times. This has

been done especially in France and Belgium, where the discoveries of

palæolithic skeletons and skulls have been far more frequent than

elsewhere. Debierre in his _L'Homme avant l'histoire_, published in

the _Bibliothèque Scientifique_ of 1888, enumerates upwards of forty

instances of such undoubted Quaternary human remains, of which at

least twenty consisted of entire skulls, and others of jaws and other

important bones connected with racial type.

The best and latest conclusions of modern anthropology from these

remains will be found in this work of Debierre's, and in Hamy's

_Palæontologie humaine_, Quatrefages' _Races humaines_, and

Topinard's _Anthropologie_, and it will be sufficient to give a short

summary of the results.

The history of Quaternary fossil man is divided, in the _Crania

Ethnica_ of Quatrefages and Hamy, into four races: 1st, the Canstadt

race; 2nd, the Cro-Magnon race; 3rd, the races of Grenelle and

Furfooz; 4th, the race of Truchere.

The Canstadt race, so called from the first skull of this type,

which was discovered in the loess of the valley of the Rhone near

Wurtemburg, though it is better known from the celebrated Neanderthal

skull, which gave rise to so much discussion, and was pronounced by

some that of an idiot, by others the most pithecoid specimen of a

human skull yet known, in fact almost the long-sought-for missing

link.

A still later discovery, however, has set at rest all doubt as to

the reality of this Neanderthal type, and of its being the oldest

Quaternary human type known in Western Europe. In the year 1886 two

Belgian savants, Messrs. Fraissent and Lohest, one an anatomist,

the other a geologist, discovered in a cave at Spy near Namur two

skeletons with the skulls complete, which presented the Neanderthal

type in an exaggerated form. They were found under circumstances

which leave no doubt as to their belonging to the earliest Quaternary

deposit, being at the bottom of the cave, in the lowest of three

distinct strata, the two uppermost of which were full of the usual

palæolithic implements of stone and bone, while the few found in the

lowest stratum with the skeletons were of the rudest description.

Huxley pronounces the evidence such as will bear the severest

criticism, and he sums up the anatomical characters of the skeletons

in the following terms--

"They were short of stature, but powerfully built, with strong,

curiously curved thigh-bones, the lower ends of which are so

fashioned that they must have walked with a bend at the knees.

Their long depressed skulls had very strong brow-ridges, their lower

jaws, of brutal depth and solidity, sloped away from the teeth

downwards and backwards, in consequence of the absence of that

especially characteristic feature of the higher type of man, the chin

prominence."

M. Fraissent says, "We consider ourselves in a position to say that,

having regard merely to the anatomical structure of the man of Spy,

he possessed a greater number of pithecoid characters than any other

race of mankind."

And again he says--

"The distance which separates the man of Spy from the modern

anthropoid ape is undoubtedly enormous; but we must be permitted to

point out that if the man of the Quaternary age is the stock whence

existing races have sprung, he has travelled a very great way. From

the data now obtained, it is permissible to believe that we shall

be able to pursue the ancestral type of man and the anthropoid apes

still further, perhaps as far as the Eocene and even beyond."

This Canstadt or Neanderthal type was widely diffused early in the

Quaternary period, having been found in a skull from the breccia

of Gibraltar, in skulls from Italy, Spain, Austria, Sweden, and in

France, Belgium, and Western Germany; in fact almost everywhere

where skulls and skeletons have been found in the oldest deposits

of caves and river-beds, notably in the alluvia of the Seine valley

near Paris, where three distinct superimposed strata are found,

each with different human types, that of Canstadt being the oldest.

Wherever explorations have been carefully made it seems to be certain

that the oldest race of all in Europe was dolicocephalic, and

probable that it was of the Canstadt type, the skulls of which are

all low and long, the length being attained by a great development

of the posterior part of the head, which compensates for a deficient

forehead.

This type is also interesting because, although the oldest, it shows

occasional signs of survival through the later palæolithic and

neolithic ages down to recent times. The skulls of St. Manserg, a

mediæval bishop of Toul, and of Lykke, a scientific Dane of the last

century, closely resemble the Neanderthal skull in type, and can

scarcely be accounted for except as instances of that atavism, or

reversion to old ancestral forms, which occasionally crops up both

in the human and in animal species. It is thought by many that these

earliest palæolithic men may be the ancestors of the tall, fair,

long-headed race of Northern Europe; and Professor Virchow states

that in the Frisian islands off the North German coast, where the

original Teutonic type has been least affected by intermixture, the

Frisian skull unmistakably approaches the Neanderthal and Spy type.

But if this be so, the type must have persisted for an immense time,

for, as Huxley observes, "the difference is abysmal between these

rude and brutal savages, and the comely, fair, tall, and long-headed

races of historical times and of civilized nations." At the present

day the closest resemblance to the Neanderthal type is afforded by

the skulls of certain tribes of native Australians.

Next in antiquity to the Canstadt type, though still in the early age

when the mammoth and cave-bear were abundant, and the implements and

weapons still very rude, a totally different type appears, that of

Cro-Magnon. The name is taken from the skeleton of an old man, which

was found entire in the rock shelter of Cro-Magnon in the valley of

the Vezere, near the station of Moustier, which gave the type of some

of the oldest and rudest stone implements of the age of the mammoth.

The skeleton was found in the inner extremity of the shelter,

buried under a mass of _débris_ and fallen blocks of limestone, and

associated with bones of the mammoth and implements of the Moustier

type, so that there can be no doubt, of its extreme antiquity.

The skull, like that of the Canstadt type, is dolichocephalic,

but in all other respects totally different. The brow-ridges and

generally bestial characters have disappeared; the brain is of

fair or even large capacity; the stature tall; the forehead fairly

high and well-rounded; the face large; the nose straight, the jaws

prognathous, and the chin prominent.

This type is found in a number of localities, especially in the

south-west of France, Belgium, and Italy, and it continued through

the quaternary into the neolithic period, being found in the caves

of the reindeer age, and in the dolmens. It is thought by some

ethnologists to present analogies to the Berber type of North Africa,

and to that of the extinct Guanches of the Canary Islands.

Coexistent with or a little later than this type is one of a totally

different character both from it and from that of Canstadt, viz. that

of a brachycephalic race of very short stature, closely resembling

the modern Lapps. This has been subdivided into the several races

of Furfooz, Grenelle, and Truchere, according to the degree of

brachycephaly and other features; but practically we may look on

these as the results of local variations or intercrossings, and

consider all the short, brachycephalic races as forming a third type

sharply opposed to those of Canstadt and Cro-Magnon.

We have thus distinct evidence that the Quaternary fauna in Europe

comprised at least three distinct races of palæolithic men, and there

is a good deal of evidence for the existence of a fourth distinct

race in America with features differing from any of the European

races, and resembling those of the native American men in recent

times. But this affords absolutely no clue as to the existence of

other palæolithic types in Asia, Africa, India, Australia, and other

countries, forming quite three-fourths of the inhabited world, in

which totally different races now exist and have existed since the

commencement of history, who cannot possibly have been derived from

any of the European types within the lapse of time comprised within

the Quaternary period.

The Negro race is the most striking instance of this, for it differs

essentially from any other in many particulars, which are all in the

direction of an approximation towards the pithecoid type.

The size of the brain is less, and a larger proportion of it is

in the hinder half; the muzzle much more projecting, and the

nose flatter; the fore-arm longer; and various other anatomical

peculiarities all point in the same direction, though the type

remains perfectly human in the main features. It diverges, however,

from the known types of Quaternary man in Europe and from the

American type, as completely as it does from those of modern man,

and it is impossible to suppose that it can be derived from them, or

they from it, in the way of direct descent. If there is any truth

in evolution, the Negro type must be one of the oldest, as nearest

to the animal ancestor, and this ancestor must be placed very far

back beyond the Quaternary period, to allow sufficient time for the

development of such entirely different and improved races.

This will be the more evident if we consider the case of the pygmy

Negritos and Negrillos, who are spread over a wide tropical belt

of half the circumference of the earth, from New Guinea to Western

Africa. They seem originally to have occupied a large part of this

belt, and to have been driven into dense forests, high mountains,

and isolated islands, by taller and stronger races, such as the

true Negro, the Melanesian, and the Malay, and probably represent

therefore a more primitive race. But they had already existed long

enough to develop various sub-types among themselves, for although

always approaching more to the Negro type than any other, the Asiatic

Negrito and the African Negrillo and Bushman differ in the length of

skull, colour, hair, prognathism, and other particulars. But they all

agree in the one respect which makes it impossible to associate them

with any known Quaternary type, either as ancestors or descendants,

viz. that of dwarfish stature. As a rule the Bushmen and Negritos do

not average above four feet six inches, and the females three inches

less; while in some cases they are as low as four feet--_i.e._ they

are quite a foot shorter than the average of the higher races, and

nearly a foot and a half below that of the Quaternary Cro-Magnon and

Mentone skeletons, and of the modern Swedes and Scotchmen. And they

are small and slightly built in proportion, and by no means deformed

specimens of humanity. Professor Flower suggests that they may be

"the primitive type from which the African Negroes on the one hand,

and the Melanesians on the other have sprung." In any case they must

certainly have existed as a distinct type in the Quaternary period,

and probably much earlier. It is remarkable also that the very oldest

human implements known get continually smaller as they get older,

until those of the Miocene, from Thenay and Puy Courny, are almost

too small for the hands even of Stanley's pygmies. If mere guesses

were worth anything, it would be rather a plausible one that the

original Adam and Eve were something between a monkey and an Andaman

islander.

In concluding this summary of the evidence as to Quaternary man,

I must remark on the analogy which it presents to that of the

historical period dealt with in the earlier chapters. In each case

we have distinct evidence carrying us a long way back; in that of

the historical period for 7000 years; in that of the Quaternary for

a vastly longer time, which, if the effects of high eccentricity,

postulated by Croll's theory, had any influence on the two last

glacial periods, cannot be less than 200,000 years, an estimate which

is confirmed by the amount of geological work and changes of flora

and fauna which have taken place. In each case also the positive

evidence takes us back to a state of things which gives the most

incontrovertible proof of long previous existence; in the historical

case the evidence of a dense population and high civilization

already long prevailing when written records began; in the case of

palæolithic man, that of his existence in the same state of rude

civilization in the most remote regions, and over the greater part

of the habitable earth, his almost uniform progression upwards from

a lower to a higher civilization, and his existing at the beginning

of the Quaternary period already differentiated into races as remote

from one another as the typical races of the present day. These facts

of themselves afford an irresistible presumption that the origin of

the human race must be sought much further back, and it remains to

consider what positive evidence has been adduced in support of this

presumption.

CHAPTER XI.

TERTIARY MAN.

Definition of Periods--Passage from Pliocene

to Quaternary--Scarcity of Human Remains in

Tertiary--Denudation--Evidence from Caves wanting--Tertiary Man

a necessary inference from widespread existence of Quaternary

Man--Both equally inconsistent with Genesis--Was the first great

Glaciation Pliocene or Quaternary?--Section of Perrier--Confirms

Croll's Theory--Elephas Meridionalis--Mammoth--St. Prest--Cut

Bones--Instances of Tertiary Man--Halitherium--Balæonotus--Puy

Courny--Thenay--Evidence for--Proofs of Human Agency--Latest

Conclusions--Gaudry's Theory--Dryopithecus--Type of Tertiary

Man--Skeleton of Castelnedolo--- Shows no approach to the

Missing Link--Contrary to Theory of Evolution--- Must be sought

in the Eocene--Evidence from the New World--Glacial Period in

America--Palæolithic Implements--Quaternary Man--Similar to

Europe--California--Conditions different--Auriferous Gravels---

Volcanic Eruptions--Enormous Denudation--Great Antiquity--Flora

and Fauna--Point to Tertiary Age--Discovery of Human

Remains--Table Mountain--Latest Finds--Calaveras Skull--Summary

of Evidence--Other Evidence--Tuolumne--Brazil--Buenos

Ayres--Nampa Images--Take us farther from First Origins and the

Missing Link--If Darwin's Theory applies to Man, must go back to

the Eocene.

The first difficulty which meets us in this question is that of

distinguishing clearly between the different geological periods. No

hard-and-fast line separates the Quaternary from the Pliocene, the

Pliocene from the Miocene, or the Miocene from the Eocene. They pass

from one into the other by insensible gradations, and the names given

to them merely imply that such considerable changes have taken place

in the fauna as to enable us to distinguish one period from another.

And even this only applies when we take the periods as a whole, and

see what have been the predominant types, for single types often

survive through successive periods. The course of evolution seems to

be that types and species, like individuals, have their periods of

birth, growth, maturity, decay, and death. Thus fish of the ganoid

type appear sparingly in the Silurian, culminate in the Devonian, and

gradually die out in the later formations. So also Saurian reptiles

appear in the Carboniferous, culminate in the Lias, and die out with

the Secondary, or so nearly so that the crocodilia are their sole

remaining representatives.

And this applies when we attempt to take our first step backwards in

tracing the origin of man, and follow him from the Quaternary into

the Pliocene. When did the Pliocene end and the Quaternary begin?

Within which of the two did the first great glacial period fall? Does

pre-glacial mean Pliocene, or is it included in the Quaternary? and

to which do the oldest human remains belong, such as the skeletons of

Spy?

The difficulty of answering these questions is increased because,

as we go back in time, the human remains which guide us in the

Quaternary age necessarily become scarcer. Mankind must have been

fewer in number, and their relics to a great extent removed by

denudation. Thus the evidence from caves, which affords by far the

most information as to Quaternary man, entirely fails us as to the

Pliocene and earlier periods. This may be readily accounted for when

we consider the great amount of the earth's surface which has been

removed by denudation. In fact we have seen that nearly 2000 feet of

a mountain range must have disappeared from denudation in the Weald

of Kent, since the streams from it rolled down the gravels with human

implements, scattered over the North Downs as described by Professor

Prestwich. What chance would Tertiary caves have of surviving such an

extensive denudation? Moreover, if any of the present caves existed

before the glacial period, their original contents must have been

swept out, perhaps more than once, before they became filled by the

present deposits. There is evidence in many caves that this was the

case, from small patches of the older deposit being found adhering

to the roof, as at Brixham and Maccaguone in Sicily, in which latter

case flakes of chipped stone and pieces of carbon were found by Dr.

Falconer in these patches of a hard breccia.

There is another consideration also which must have greatly

diminished the chance of finding human remains in Tertiary deposits.

Why did men take to living in dark and damp caves? Presumably for

protection against cold. But in the Miocene and the greater part

of the Pliocene there was no great cold. The climate, as shown by

the vegetation, was mild, equable, and ranged from semi-tropical to

south-temperate, and the earth was to a certain extent covered by

forests sustaining many fruit-bearing trees. Under such conditions

men would have every inducement to live in the open air, and in or

near forests where they could obtain food and shelter, rather than

in caves. And a few scattered savages, thus living, would leave

exceedingly few traces of their existence. If the pygmy races of

Central Africa, or of the Andaman Islands, became extinct, the

chances would be exceedingly small of a future geologist finding

any of their stone implements, which alone would have a chance of

surviving, dropped under secular accumulations of vegetable mould in

a wide forest.

It is the more important therefore where instances of human remains

in Tertiary strata, supported by strong _primâ facie_ evidence,

and vouched for by competent authorities, do actually occur, to

examine them dispassionately, and not, as a good many of our English

geologists are disposed to do, dismiss them with a sort of scientific

_non possumus_, like that which was so long opposed to the existence

of Quaternary man, and the discoveries of Boucher-de-Perthes. It is

perfectly evident from the admitted existence of man throughout the

Quaternary period, already spread over a great part of the earth's

surface, and divided into distinct types, that if there is any truth

in evolution, mankind must have had a long previous existence. The

only other possible alternative would be the special miraculous

creations of men of several different types, and in many different

centres, at the particular period of time when the Tertiary was

replaced by the Quaternary. In other words that, while all the rest

of the animal creation have come into existence by evolution from

ancestral types, man alone, and that not merely as regards his

spiritual qualities, but physical man, with every bone and muscle

having its counterpart in the other quadrumana, was an exception to

this universal law, and sprang into existence spontaneously or by

repeated acts of supernatural interference.

As long as the account of the creation in Genesis was held to be a

divinely-inspired narrative, and no facts contradicting it had been

discovered, it is conceivable that such a theory might be held,

but to admit evolution for Quaternary, and refuse to admit it for

Tertiary man, is an extreme instance of "straining at a gnat and

swallowing a camel," for a duration of even 10,000 or 20,000 years is

just as inconsistent with Genesis as one of 100,000 or half a million.

In attacking the question of Tertiary man, the first point is to

aim at some clear conception of where the Pliocene ends and the

Quaternary begins. These are after all but terms applied to gradual

changes through long intervals of time; still they require some

definition, or otherwise we should be beating the air, and ticketing

in some museums as Tertiary the identical specimens which in others

were labelled as Quaternary. This turns very much on whether the

first great glaciation was Pliocene or Quaternary, and must be

decided partly by the order of superposition and partly by the fauna.

If we can find a section where a thick morainic deposit is interposed

between two stratified deposits, a lower one characterized by the

usual fauna of the Older Pliocene, and an upper one by that of the

Newer Pliocene, it is evident that the glacier or ice-cap which left

this moraine must have existed in Pliocene times. We know that the

climate became colder in the Pliocene, and rapidly colder towards

its close, and that in the cliffs of Cromer, the forest bed with

a temperate climate had given place to Arctic willows and mosses,

before the first and lowest boulder-clay had brought blocks of

Scandinavian granite to England. We should be prepared, therefore,

for evidence that this first period of greatest cold had occurred

within the limits of the Pliocene period.

Such evidence is afforded by the valleys which radiate from the great

central boss of France in the Auvergne. The hill of Perrier had

long been known as a rich site of the fossil remains of the extinct

Pliocene fauna, and its section has been carefully studied by some of

the best French geologists, whose results are summed up as follows by

Hamy in his _Palæontologie humaine_--

"The bed-rock is primitive protogine, which is covered by nearly

horizontal lacustrine Miocene, itself covered by some metres of

fluviatile gravels. Above comes a bed of fine sand, a mètre thick,

which contains numerous specimens of the well-known mammalian fauna

of the Lower Pliocene, characterized by two mastodons (_M. Armenicus_

and _M. Borsoni_). Then comes a mass of conglomerates 150 mètres

thick, consisting of pebbles and boulders cemented by yellowish mud;

and above this a distinct layer of Upper Pliocene characterized by

the _Elephas Meridionalis_.

"The boulders, some of which are of great size, are all angular,

never rounded or stratified, often scratched, and mostly consisting

of trachyte, which must have been transported twenty-five kilomètres

from the Puy de Dôme. In short, the conglomerate is absolutely

indistinguishable from any other glacial moraine, whether of the

Quaternary period or of the present day. It is divided into three

sections by two layers of rolled pebbles and sands, which could only

have been caused by running water, so that the glacier must have

advanced and retreated three times, leaving each time a moraine fifty

mètres thick, and the whole of this must have occurred before the

deposit of the Upper Pliocene stratum with its _Elephas Meridionalis_

and other Pliocene mammals."

The importance of this will presently be seen, for the _Elephas

Meridionalis_ is one of the extinct animals which is most directly

connected with the proofs of man's existence before the Quaternary

period. It is also important as confirming the immense time which

must have elapsed between the date of the first and second _maxima_

of glacial cold, and thus adding probability to the calculations

derived from Croll's periods of maximum and minimum eccentricity.

The three advances and retreats of the great Perrier glacier also fit

in extremely well with the calculated effects of precession during

high eccentricity, as about three of such periods must have occurred

in the period of the coming on, culminating, and receding of each

phase of maximum eccentricity.

This evidence from Perrier does not stand alone, for in the

neighbouring valleys, and in many other localities, isolated boulders

of foreign rocks which could only have been transported by ice, are

found at heights considerably above those of the more recent moraines

and boulders which had been supposed to mark the limit of the

greatest glaciation. Thus on the slopes of the Jura and the Vosges,

boulders of Alpine rocks, much worn by age, and whose accompanying

drifts and moraines have disappeared by denudation, are found at

heights 150 or 200 mètres above the more obvious moraines and

boulders, which themselves rise to a height of nearly 4000 feet, and

must have been the front of glaciers from the Alps which buried the

plain of Switzerland under that thickness of solid ice.

The only possible alternative to this evidence from Perrier would be

to throw back the duration of the Quaternary and limit that of the

Pliocene enormously, by supposing that all the deposits above the

great glacial conglomerate or old moraine, are inter-glacial and

not Tertiary. This is, as has been pointed out, very much a question

of words, for the phenomena and the time required to account for

them remain the same by whatever name we elect to call them. But it

still has its importance, for it involves the fundamental principle

of geology, that of classifying eras and formations by their fauna.

If the _Elephas Meridionalis_ is a Pliocene and not a Quaternary

species, we must admit, with the great majority of continental

geologists, that the first and greatest glaciation fell within the

Pliocene period. If, on the other hand, this elephant is, like the

mammoth, part of the Quaternary fauna, we may believe, as many

English geologists do, that the first glacial period coincided with

and probably occasioned the change from Pliocene to Quaternary, and

that everything above the oldest boulder-clays and moraines is not

Tertiary but inter-glacial.

As bones of the _Elephas Meridionalis_ have been frequently found in

connection with human implements, and with cuts on them which could

only have been made by flint knives ground by the human hand, it will

be seen at once what an interest attaches to this apparently dry

geological question, of the age of the great southern elephant.