GLACIAL EPOCH.
Happily for the Archaeo-geologist, there is given him a point from which
to start in his researches into the antiquity of his race. Without it
his calculations would be very indefinite and his efforts would be shorn
of much of their interest. The Glacial Epoch, that has puzzled the mind
of both the geologist and the astronomer, is a guide-post where he may
not only look both ways, but also estimate the length of ages and number
the years of man. Nothing, then, is of more importance, in this
investigation, than an understanding of the condition of the earth prior
to the glacial, and the knowledge of the date and length of this epoch.
For untold ages the earth, to all appearance, had been preparing itself
for the reception of man. There was an abundance of game, the forests
were beautiful, the domestic animals had made their appearance, the
climate was warm, the soil rich, and the coal had been formed.
Everything seemed to point to a bright and glorious future for man, who
had already entered upon the scene. It is true there were fierce and
savage beasts to contend with. These seemed but a motive power to stir
man to action and develop the resources of his mind. Should he fail for
a time to overcome the wild beasts a retreat was provided in the hollow
recesses of the earth. But nature felt her work was still unfinished.
The earth had passed through the ordeal of fire, and withstood the
devastations of water, and now her long summer must come to an end. The
arctic regions had been growing colder and colder, and the change was
felt in the countries to the south. The northern animals were being
clothed with a hairy or woolly garment for their protection. The aspect
began to be forbidding. The future prospect of man was not only gloomy,
but foreboded he should perish along with the many species of animals
that were gradually succumbing to the cold. Great fields of ice were
slowly accumulating at both the poles, and at last, by the power of
their great weight, assisted by some geographical changes, began to move
toward the equator, crushing and grinding the great rocks, and either
driving before them, or else destroying, every living thing in their
relentless march. Slowly but surely they moved on. The mountains groaned
under the enormous weight of ice. Their heads were scarred, their sides
bruised, torn and cut. The icy monsters listened not to the pleadings of
earth, the lowing of cattle, or the cries of man. Centuries elapsed
before the sun re-asserted his power. The rays of the sun, the internal
heat of the earth, and other causes, produced a change. The northern ice
was broken up by the time it reached latitude 39 deg. North America, leaving
its indelible traces in the bowlders, gravel, beds of sand and clay
which mark its course. In Europe this sheet of ice extended as far south
as Spain and Corsica. The glaciers of the Antarctic regions extended as
far as latitude 41 deg. south.
_Fauna of Europe._--Among the Fauna may be mentioned the gigantic
elephants, of nearly twice the bulk of the largest individuals that now
exist, which roamed in herds over England, and extended across the
Siberian plains and from Behring Strait to South Carolina. Two-horned
rhinoceroses wallowed in the swamps of the ancient forests.
Hippopotamuses inhabited the lakes and rivers. The great cave-bear,
which sometimes attained the size of a horse, and the cave-tiger, twice
as large as the living tiger, preyed upon the animals of less strength
than themselves. Troops of hyenas, larger than those of South America,
disputed with other beasts of prey. A species of wild-cat, lynx, and
leopard found retreats in the same forests. Then there was a remarkable
carnivorous animal called _Machairodus_, about the size of a tiger, and
from the shape and size of the sword-like teeth, must have been a very
destructive creature. The lemming and the musk ox found a home, and the
wild horse pranced about unrestrained by the hand of man. The great
Irish elks swiftly moved over the ground, and must have been very
numerous, as their remains occur in abundance in peat-bogs and
marl-pits. Nor should it be unmentioned that there was also a species of
gigantic ox nearly as large as an elephant, that subsisted on the
plains. All these animals followed the retreat of the glaciers and some
of them were in close proximity to the ice.
_Geological Period._--The glacial epoch occurred during the geological
period known as the post-tertiary. The tertiary had gradually passed
away and its time had been recorded on the pages of geological history.
A new epoch began to dawn. This was the epoch of ice, the birth and
almost the childhood of the post-tertiary.
_Probable Date._--In discussing the probable date of the glacial epoch,
Sir Charles Lyell says, "The attempt to assign a chronological value to
any of our geological periods except the latest, must, in the present
state of science, be hopeless. Nevertheless, independently of all
astronomical considerations, it must, I think, be conceded that the
period required for the coming on of the greatest cold, and for its
duration when most intense, and the oscillations to which it was
subject, as well as the retreat of the glaciers and the 'great thaw' or
disappearance of snow from many mountain-chains where the snow was once
perpetual, required not tens but hundreds of thousands of years. Less
time would not suffice for the changes in physical geography and organic
life of which we have evidence. To a geologist, therefore, it would not
appear startling that the greatest cold should be supposed to have been
two hundred thousand years ago, although this date must be considered
as very conjectural, and one which may be as likely to err in deficiency
of time as in excess."[6]
Sir John Lubbock, in his dissent from some calculations made by Mr.
Geikie on the general effect produced by rivers in excavating valleys
and lowering the general level of the country, says, "As regards the
higher districts, however, his data are perhaps not far wrong, and if we
apply them to the valley of the Somme, where the excavation is about two
hundred feet in depth, they would indicate an antiquity for the
palaeolithic epoch of from one hundred thousand to two hundred and forty
thousand years."[7]
Dana, in his chapter on the length of geological time, says, in speaking
of the time required to excavate the gorge of Niagara River, that "on
both sides of the gorge near the whirlpool, and also at Goat Island,
there are beds of recent lake shells ... the same kinds that live in
still water near the entrance to the lake, and which are not found in
the rapids. The lake, therefore, spread its still waters, when these
beds were formed, over the gorge above the whirlpool. A tooth of a
mastodon (_M. giganteus_) has been found in the same beds. This locates
the time in the Champlain epoch.... Six miles of the gorge have been
excavated since that mastodon was alive....
"There is a lateral valley leading from the whirlpool through the
Queenstown precipice at a point a few miles west of Lewiston. This
valley is filled with drift of the glacial epoch, and this blocking up
of the channel may have compelled it to open a new passage.
"If, then, the falls have been receding six miles, and we can ascertain
the probable rate of progress, we may approximate to the length of time
it required. Hall and Lyell estimated the average rate at one foot a
year,--which is certainly large. Mr. Desor concluded, after his study of
the falls, that it was 'more nearly three feet a century than three feet
a year.' Taking the rate at one foot a year, the six miles will have
required over thirty-one thousand years; if at one inch a year--which is
eight and one third feet a century--three hundred and eighty thousand
years."[8]
The calculation made by Dana is for the Champlain epoch. As this epoch
was subsequent to the glacial, the time must be either thrown still
farther back, or else allow the calculations to begin with the end of
the glacial.
_Probable Duration._--Lyell has attempted to form an estimate of the
duration of the glacial epoch by considering "the most simple series of
changes in physical geography which can possibly account for the
phenomena of the glacial period," and enumerates as follows:
"First, a continental period, toward the close of which the forest of
Cromer flourished; when the land was at least five hundred feet above
its present level, perhaps much higher, and its extent probably greater
than that given in the map, Fig. 41." (In this map the whole of the
British Isles are connected with one another, and with the
continent--the German Ocean and the English Channel constituting dry
land).
"Secondly, a period of submergence, by which the land north of the
Thames and Bristol Channel, and that of Ireland, was gradually reduced
to an archipelago; and finally to such a general prevalence of sea as is
seen in map, Fig. 39." (This map is intended to represent the British
Isles as they appeared above water when Scotland was submerged to two
thousand feet and other parts of the isles to one thousand three hundred
feet.) "This was the period of submergence and of floating ice, when the
Scandinavian flora, which occupied the lower grounds during the first
continental period, may have obtained exclusive possession of the only
lands not covered with perpetual snow.
"Thirdly, a second continental period, when the bed of the glacial sea,
with its marine shells and erratic blocks, was laid dry, and when the
quantity of land equalled that of the first period.... During this
period there were glaciers in the higher mountains of Scotland and
Wales....
"The submergence of Wales to the extent of one thousand four hundred
feet, as proved by glacial shells, would require fifty-six thousand
years, at the rate of two and a half feet per century; but taking
Professor Ramsay's estimate of eight hundred feet more, that depression
being required for the deposition of some of the stratified drift, we
must demand an additional period of thirty-two thousand years, amounting
in all to eighty-eight thousand; and the same time would be required for
the reelevation of the tract to its present height. But if the land rose
in the second continental period no more than six hundred above the
present level ... this ... would have taken another twenty-six thousand
years; the whole of the grand oscillation, comprising the submergence
and reemergence, having taken, in round numbers, two hundred and
twenty-four thousand years for its completion; and this, even if there
were no pause or stationary period, when the downward movement ceased,
and before it was converted into an upward one."[9]
Lyell admits that the average rate of two and a half feet per century is
a purely arbitrary and conjectural one, and there are cases where the
change is even six feet a century, yet the average rate of motion, he
thinks, will not exceed that above proposed. With this opinion, Lubbock
believes most geologists will agree.[10]
By the estimates already given a basis is formed upon which a
calculation can be made as to the time when this epoch began. At the
time of the most intense cold the eccentricity of the earth's orbit
was .0575; the difference in millions of miles between the greatest and
least distances of the earth from the sun 10-1/2; the number of days by
which winter, occurring in aphelion was longer than the summer in
perihelion 27.8; the mean temperature of the hottest summer month in
the latitude of London when the summer occurs in perihelion, 113 deg.; the
mean temperature of the coldest winter month in the latitude of London
when the winter occurs in aphelion, 0 deg. 7'. Sixty thousand years later
the eccentricity of the earth's orbit was but .0332; the difference of
distance in millions of miles was 6; number of winter days in
excess, 16.1; mean of hottest month in latitude of London, 95 deg., and mean
of coldest month 12 deg.. It is evident then at this time (one hundred and
fifty thousand years ago) a "great thaw" had taken place and the
glaciers driven back, although fifty thousand years later less intense
cold set in again. If thirty thousand years be allowed for the "great
thaw" from the extreme point of cold, and that extreme point to have
been two hundred and ten thousand years ago, then one hundred and eighty
thousand years ago the glaciers had become so broken up as to allow
vegetation to spring up in many localities, and the wild beasts to
partially reassert their dominion. If to this be added the time required
for the duration of the glacial epoch (two hundred and twenty-four
thousand years) then the time when the ice began to accumulate was four
hundred and four thousand years ago. But if the tables of Mr. Croll be
correct, their beginning could not have been earlier than three hundred
and fifty thousand years ago, as the eccentricity of the earth's orbit
varied but little from the present, and five hundred and fifty thousand
years ago it was almost identical with that of the present.[11]
During the last stages of this ocean of ice it must have melted very
rapidly,[12] for great rivers were formed, and the water pouring down
its icy bed sought other streams, and on the bosom of the earth swept
away loose sediment, depositing it along the course of rivers and in
caves of the earth, covering the remains of man along with those of
animals that perished during the long winter of ice.
[Illustration: FIG. 2. STREAM ISSUING FROM A GLACIER.]
_Evidences of the Existence of Man._--The traces of man in the deposits
made during the glacial epoch are numerous. Out of the many, the most
noted will be given, with a view to their chronological order.
In all probability the very oldest implements of the post-tertiary, and
consequently the beginning of the glacial epoch, if not of the pliocene,
are those found in the south of Hampshire, between Gosport and
Southampton. They came from a tabular mass of drift which caps the
tertiary strata. "The great bed of gravel resting on eocene tertiary
strata, in which these implements have been found, consists in most
places of half-rolled or semi-angular chalk flints, mixed with rounded
pebbles washed out of the tertiary strata.... Many of them exhibit the
same colors and ochreous stain as do the flints in the gravel in which
they lay."
West of the Southampton estuary, "on both sides of the opening at
Bournemouth, flint tools of the ancient type have been met with in the
gravel capping the cliffs. The gravel from which the flint tool was
taken at Bournemouth is about one hundred feet above the level of the
sea.... The gravel consists in great part of pebbles derived from
tertiary strata."
The oval flint implement discovered in gravel at the top of the Foreland
cliff "is of the true palaeolithic type, and the gravel in which it is
imbedded at the height of about eighty feet above the level of the sea,
may have once extended to the cliffs near Gosport; in which case we
should have to infer that the channel called the Solent had not yet
been scooped out when this region was inhabited by palaeolithic man."[13]
It may be safely inferred that the implements in the above three
enumerations were imbedded at about the same time.
The flint implements from the valley of the Somme, which have been of so
much interest, and convinced so many sceptical geologists, belong to the
early part of this epoch. This valley may be represented by Fig. 3.
[Illustration: FIG. 3. SECTION ACROSS THE SOMME IN PICARDY.
1. Peat, twenty to thirty feet thick, resting on gravel, _a_.
2. Lower level gravel, with elephants' bones and flint tools
covered with fluviatile loam, twenty to forty feet thick.
3. Upper level gravel, with similar fossils, and overlying loam.
In all thirty feet thick.
4. Upland loam without shells, five or six feet thick.
5. Eocene tertiary strata, resting on the chalk in patches.]
In explanation of the above it may be well to remark that No. 2
indicates the lower level gravels, and No. 3 the higher ones, which are
from eighty to one hundred feet above the river. Of a later date than
these is the peat, No. 1, which is from ten to thirty feet in thickness.
Underneath the peat is a bed of gravel, _a_, from three to fourteen feet
thick, resting on undisturbed chalk. But between the gravel and the peat
is a thin layer of impervious clay. This section of the valley of the
Somme is a pretty fair representation of the arrangements of the
different beds at Abbeville, Amiens, and and St. Acheul.
In these beds are the records of two drift periods, marked by 2 and 3.
The two are separated by a layer of fresh-water deposits, which contains
river shells and is sometimes as much as sixteen feet thick. The lower,
or gray diluvium, (No. 2), marks the glacial epoch, as distinct from the
glaciers of the reindeer epoch. In the lower gravel, lying immediately
upon the tertiary formation, were found the flint hatchets, together
with the bones of the mammoth and fossil rhinoceros.
In order to understand the deposits still more clearly, the following
figure is given.
[Illustration: FIG. 4. SECTION OF A GRAVEL-PIT AT ST. ACHEUL.
1. Vegetable and made soil from two to three feet thick.
2. Brown loam from four to five feet thick, containing a few
angular flints.
3. Bed of sandy marl from five to six feet thick, with land and
fresh-water shells, covered with a thin layer of angular gravel
from one to two feet thick.
4. A bed of partially rounded gravel containing well-rolled
tertiary pebbles. In this bed the flint implements are chiefly
found--ten to fourteen feet thick.
5. Formation of chalk.
_a._ Part of elephant's molar, eleven feet from surface.
_b._ Entire molar of mammoth (_E primigenius_), seventeen feet
from surface.
_c._ Position of flint hatchet, eighteen feet from surface.
_d._ Gravel projecting five feet.]
At St. Acheul, in bed No. 4, were found large numbers of flint
implements. Some of them have the shape of a spear-head, and are over
seven inches in length. The oval-shaped hatchets are so rude in some
instances as to require a practised eye to decide their human origin. In
the same bed are found small round bodies having a tubular cavity in the
centre. Dr. Rigollot has suggested that these perforated stones or
gravel were used as ornaments, possibly strung together as beads.
In this bed, No. 4, seventeen feet from the surface, was found a
mammoth's tooth. About one foot below the tooth, in densely compressed
gravel, was found a stone hatchet of an oval form.
[Illustration: FIG. 5. FLINT IMPLEMENT FROM ST. ACHEUL.
Half the size of the original, which is seven and a half inches
long.
_a._ Side view.
_b._ Same seen edgewise.
"These spear-headed implements have been found in greater number,
proportionally to the oval ones, in the upper level gravel at St.
Acheul, than in any of the lower gravels in the valley of the
Somme. In these last, the oval form predominates, especially at
Abbeville."--_Antiquity of Man_, p. 114.]
That this bed was formed by action of glaciers is shown, not only from
the well-rounded tertiary pebbles, but also from the great blocks of
hard sandstone, some of which are over four feet in diameter. These
large fragments not only abound at St. Acheul in both the higher and
lower level gravels at Amiens, and at the higher level at Abbeville, but
they are also traced far up the valley wherever the old diluvium occurs.
All of these sandstones have been derived from the tertiary strata which
once covered the chalk.
[Illustration: FIG. 6. FLINT IMPLEMENT FROM ABBEVILLE.
_a._ Oval-shaped flint hatchet from Mautort near Abbeville, half
size of original, which is five and a half inches long, from
a bed of gravel underlying the fluvio-marine stratum.
_b._ Same seen edgewise.
_c._ Shows a recent fracture of the edge of the same at the point
_a_, or near the top. This portion of the tool, _c_, is drawn
of the natural size, the black central part being the unaltered
flint, the white outer coating, the layer which has been formed
by discoloration or bleaching since the tool was first made.
The entire surface of Figure 6 must have been black when first
shaped, and the bleaching to such a depth must have been the
work of time, whether produced by exposure to the sun and air
before it was imbedded, or afterward when it lay deep in the
soil.--_Antiquity of Man._]
As the flint implements of Abbeville and Amiens are the same as those of
St. Acheul, and from the same beds, what has already been said will
apply to them. These implements have been found in these localities in
great numbers, as several thousand of them already taken from the beds
will amply testify.
From the gravel-pit in which were found the flint axes, at Abbeville,
and close to the ancient chalk, was taken the celebrated human bone
known as the _jaw_ of Moulin-Quignon. It was cotemporary with the axes,
and undoubtedly some of the flint implements there found were fashioned
by the man of whom that jaw formed so necessary a part.
This jaw-bone belonged to an old man, and is described as displaying "a
tendency toward the animal structure in the shortness and breadth of the
ascending ramus (the perpendicular portion of the lower jaw), the equal
height of the two apophyses (a process or regular prominence forming a
continuous part of the body of the bone), the indication of prognathism
(projecting jaw) furnished by the very obtuse angle at which the ramus
joins the body of the bone.[14]
Near the same locality other human bones were discovered Which presented
the same characteristics.
Boucher de Perthes having pointed out that flint implements could be
found in the valley of the Seine, in beds similar to those of Abbeville,
the antiquaries were soon rewarded and Boucher de Perthes' prediction
was fulfilled. M. Gosse, of Geneva, found the Abbeville type of
implements in the lowest diluvial deposits associated with the remains
of animals of that period.
The discovery made by Casiano de Prado, near Madrid, is very similar to
those of Abbeville. "First, vegetable soil; then about twenty-five feet
of sand and pebbles, under which was a layer of sandy loam, in which,
during the year 1850, a complete skeleton of the mammoth was discovered.
Underneath this stratum was about ten feet of coarse gravel, in which
some flint axes, very closely resembling those of Amiens, have been
discovered."[15]
The remains of man are also preserved in caverns associated with the
fossil bones of the mammoth, the woolly-haired rhinoceros, cave-bear,
and other extinct quadrupeds. Among these should be noticed Kent's Hole,
which has furnished a mine of wealth. Of his discoveries Godwin-Austen
says: "Human remains and works of art, such as arrow-heads and knives of
flint, occur in all parts of the cave, and throughout the entire
thickness of the clay; and no distinction founded on condition,
distribution, or relative position can be observed, whereby the human
can be separated from the other reliquiae," which included bones of the
mammoth (_E. primigenius_), rhinoceros (_R. tichorrhinus_), cave-bear
(_Ursus spelaeus_), cave-hyena (_H. spelaeus_), and other mammalia. These
researches were conducted in parts of the cave which had never been
disturbed, and the works of man, in every instance, were procured from
undisturbed loam or clay, beneath a thick covering of stalagmite; and
all these must have been introduced before the stalagmite flooring had
been formed.[16] These specimens of man's handicraft were found far
below the stalagmite floor.[17] Closely allied to Kent's Hole is Brixham
Cave. The following gives the general succession of deposits forming the
contents of the cavern:
1. A layer of stalagmite varying from one to fifteen inches in
thickness.
2. Next below, ochreous cave-earth, from one foot to fifteen feet in
thickness.
3. Rounded gravel, in some places more than twenty feet in depth.
In the second layer there were found the remains of the mammoth,
rhinoceros, cave-bear, cave-hyena, cave-lion, reindeer, and seven other
species. Indiscriminately mixed with these bones were found many flint
knives, but chiefly from the lowest part of the ochreous cave-earth,
varying in depth from ten inches to thirteen feet. The antiquity of
these cannot be doubted, from the simple fact, even if there was no
other, that in close proximity to a very perfect flint tool was
discovered the entire left hind leg of a cave-bear, and every bone in
its natural position. From the bone earth there were taken fifteen
knives, recognized, by the experienced antiquaries, as having been
artificially formed. In the lowest gravel, underlying all, there were
found imperfect specimens of flint knives. The fine layer of mud was
deposited by the slow but regular action of water. Since these layers
were formed the stream has cut its channel seventy-eight feet below its
former level.[18]
On both banks of the Meuse, at Maestricht (Hollerd) are terraces of
gravel covered with loess. Below the city, on the left bank, one of
these terraces projects into the alluvial plain of the Meuse. During the
construction of the canal the terrace was opened to a depth of sixty
feet. The upper twenty feet consisted of loess and the lower forty feet
of stratified gravel. Great numbers of molars, tusks, and bones of
elephants, together with those of other mammalia, and a human lower jaw
with teeth, were found in or near this gravel. The human jaw was at a
depth of nineteen feet from the surface, in a stratum of sandy loam,
beneath a stratum of pebbly and sandy beds, and immediately above the
gravel. The stratum from which the jaw was taken was intact and had
never been disturbed. But the jaw was somewhat isolated, and the nearest
fossil object was the tusk of an elephant six yards distant, though on a
horizontal plane. This fossil is probably older than that discovered at
Lahr. It was probably covered just before the gush of the water when it
first began to flow from the gorges and had washed the ground at some
distance from the ice.[19]
The human skeleton from the undisturbed loess of the Rhine, near Lahr,
was found in nearly a horizontal position, but in such a manner as to
forbid the idea of sepulchre. These bones were exhumed from a
perpendicular cliff of solid loess, about five feet high. The town of
Lahr is situated four miles from, and about one hundred feet above, the
Rhine, and not far from the tributary valley drained by the Schutter,
flowing from the Black Forest.
In the alluvial plain into which the Schutter flows the the loess is two
hundred feet thick. The loess rises eighty feet above the Schutter. At
Lahr it has been denuded so as to form a succession of terraces on the
right bank. It was in the lowest of these from which the skeleton was
taken. Immediately below this bed there were found pebbles, and still
lower down was a bed of gravel containing rounded stones of sandstone
and gneiss from the Black Forest.
There are several interesting facts connected with this discovery. M.
Boue considers that the loess of the Lahr is continuous with that of the
Rhine, and before the loess had been denuded there was not less than
eighty feet of loamy deposit above the human skeleton. The glaciers had
deposited their great gravel beds, and had began to melt. The melting of
them had formed a mixture of loam and gravel. Then when the torrents
poured forth from the glaciers the loam was formed without the pebbles.
The unfortunate man, whose remains were found, was buried far beneath
the surface, during the very first part of the course of the violent
streams pouring forth from the field of ice. The glaciers were then on
the retreat, and the incautious man probably fell a victim while on the
chase.[20]
The cave of La Naulette, Belgium, afforded a jaw-bone similar to the
Moulin-Quignon. The bone came from a river deposit of loam covered with
a layer of stalagmite, and at a depth of thirteen feet from the surface.
Associated with it were the remains of the mammoth, woolly-haired
rhinoceros, and flint implements. These implements present the same type
as those of St. Acheul. With this jaw were also found a human ulna, two
human teeth, and a fragment of a worked reindeer born. This jaw-bone is
very thick, round in form, and the projection of the chin is almost
entirely absent. The chin is said to hold an intermediate position
between that of the animals and those of the present race of men. The
cavities for the reception of the canine teeth are very wide, and one of
the most remarkable things is that the three molars are reversed, that
is the first true molar is the smallest, and the last the largest. The
inner surface of the jaw at the point of the suture or symphysis, forms
a line obliquely directed upwards. Taking the jaw all in all, it is the
most ape-like human jaw ever discovered.[21]
The flint implements from Hoxne were found under three different layers
or beds. The first, vegetable, a foot and a half in depth. The second
was clay, seven and a half feet thick. The third, a bed of sand, with
shells one foot in thickness. The fourth layer, containing the
implements was a bed of gravel two feet in depth. The number of these
flints was so great that they were carried out by the baskets-full, and
thrown into the ruts of the adjoining road. On account of the great
number, this spot might have been the place where they were
manufactured. Their date is not coeval with the bowlder clay, but
undoubtedly belong, to the last of this epoch.
The human bones found in the loess of the Rhine, near Colmar, were two
fossilized fragments of the skull. They were found in undisturbed soil
along with the fossil bones of the extinct species of mammoth, horse,
gigantic deer, aurochs, and other mammalia. The fragment of the skull
"showed a depressed forehead, strongly projecting superciliary arches,
and a type, on the whole, approaching the so-called _dolichocephalic_,
or long-headed form."[22] These remains date so near the end of the
glacial as to almost enter the inter-glacial.