alive twelve thousand years ago. But the
grounds of such a calculation are in more than
one respect uncertain.

Off now to America. There, in the basin of
the Mississippi, and especially in the valleys
of the Ohio and its tributaries, large mounds
have been discovered which represent the
temples, watch-towers, fortresses, burial-places,
of an ancient unknown race. Their skulls seem
to be Mexican or Toltecan. The ruins of their
dwellings and temples are so ancient that rivers
have had time to encroach upon and undermine
their lower terraces, and again to recede for the
distance of nearly half a mile. When the first
European settlers came into this region they found
vast forests, tenanted only by the Red Indian
hunter, who had preserved no tradition of the
preceding race. Yet among those great mounds,
that are the record of their past existence, are
found evidences of their traffic; copper from Lake
Superior, mica from the Alleghanies, obsidian from
the Mexican mountains, and sea-shells from the
Gulf of Mexico. There are articles of silver as
well as of copper, pottery and ornamental sculpture,
besides stone weapons, some of unpolished
hornstone, resembling flint implements found
near Amiens and elsewhere in Europe.

Many uncertainties attach to the calculation
of Dr. B. Dowler, that a skeleton, found sixteen
feet deep under four buried forests, in digging
for gasworks in the delta of the Mississippi,
near New Orleans, has an antiquity of fifty
thousand years. A low part of the peninsula of
Florida is being formed by coral reefs.
Professor Agassiz calculates from the natural site of
the growth of coral, that it has taken a hundred
and thirty-five thousand years to form the
southern half of this peninsula, all being of
post-tertiary origin. In a part of this series of
reefs—estimated by the same calculation to be
ten thousand years old—the jaws, teeth, and
bones of the foot of a man were found.

Within the time of man, and partly within
historical times, there have been great changes
in the relative levels of land and water. In
the central district of Scotland there has been
so much upheaved, that five canoes have been
found buried in silt under the streets of Glasgow.
There is a raised beach containing living marine
shells, at Leith, and it is twenty-five feet high
above high-water mark. At the same level,
skeletons of whales and instruments of deer's-horn
have been found in the Carse of Stirling.
Iron implements have been found in the silt of
the Carse of Gowrie, and dry hillocks rising
from the plain by the estuary of the Tay, are still
called by the Celtic name of Inches: a name that
must have been given them when they rose out
of water or marsh. A great part of Scotland
has, in fact, been lifted five-and-twenty feet since
men used implements of metal, probably even
since the Roman occupation. But that twenty-five
feet rise is only the last stage of a long
course of upheaval. In parts of Norway and
Sweden, throughout an area of about a
thousand miles north and south, and for an unknown
distance east and west, the lifting of the land is
constant and is always increasing towards the
North Cape, where it is said to be at the rate of
five feet in a century. If we could assume an
average rise of two and a half feet in a century,
it would follow that the shores and a considerable
area of the former bed of the North Sea
had been uplifted vertically a hundred and
twenty-five feet, and converted into land, during
the last five thousand years. But there are on
the coast of Norway, raised beaches of
post-tertiary deposits, six hundred feet above the sea
level. They could hardly attain so great a height
in less than twenty-four thousand years. Such
calculations show, in connexion with questions
of the age of man, that there is range over a
great length of time within the limits of the
"post-tertiary" period; that is to say, the period
in which all animals are of species still living
except only a few extinct mammals.

M. CHRISTOL found in the cave of Bize, in the
department of the Oise, human bones and teeth,
with fragments of rude pottery, cemented in the
same mud and pebble which contained
land-shells of living species and the bones of
mammals, like the aurochs and reindeer, unknown
in historical times in France, and whose
remains are there found commonly associated
with those of the mammoth. Next year M.
Christol found in the cavern of Poindres, near
Nismes, human bones in the same mud with
the bones of an extinct hyæna and rhinoceros.
The conclusion to which these discoveries
pointed was not accepted. Sir Charles Lyell
himself argued that the concurrence of bones in
the caves did not prove them to be coeval.
"But," says Sir Charles, "of late years we
have obtained convincing proofs, as we shall see
in the sequel, that the mammoth, and many
other extinct mammalian species very common
in caves, occur also in undisturbed alluvium,
embedded in such a manner with works of art as
to leave no room for doubt that man and the
mammoth co-existed. Such discoveries have
led me and other geologists to reconsider the
evidence previously derived from caves brought
forward in proof of the high antiquity of man.
With a view of re-examining the evidence, I have
lately explored several caverns in Belgium and
other countries, and re-read the principal
memoirs and treatises treating of the fossil remains
preserved in them."

Among the caverns visited, were some of the
forty-two bordering the valleys of the Meuse
and its tributaries, which were explored by the
late DR. SCHMERLING of Liège. Into these
limestone caverns the streams had entered through
chinks, and left, in past ages, deposits of bones,
and, in the oldest days, flint knives, with mud,
sand, and pebbles, all of which, by the dripping
from the cavern roof of water charged with
lime, have been preserved and consolidated.
Portions of human bone were found, with flint
knives, among the remains of extinct animals:
the characteristics of age in all the bones being
equal. In the Engis cavern, eight miles from
Liège, the remains of at least three human
beings were found; the skull of one being