Atlanta tri-weekly journal. [volume] (Atlanta, Ga.) 1920-19??, 1922-10-05
The Outline of History-By H. @. Wells
|. The Romance of Mother Earth

COmploCer conclusions. Al any time some new
deposit may reveal fossils that will illuminate
this question
Certainly either mammals or the ancestors
of mammals must have lived throughout the
Mesozoic period. In the very opening chapter
Of the Mesozoic volume of the record there
were those heriomorphous reptiles to which
we ha e already alluded and in the Later Me-
sozoic a number of small jawbones are found,
entirely mammalian in character.
But there is not scrap, not BONE to sug-
gest that there lived any Mesozoic mammal
which could look dinosaur in the face. The
Mesozoic mammals or mammal-like reptiles
for we do not know clearly which they were
seem to have been all obscure little beasts
Of the size of mice and rats, more like down
trodden order Of reptiles than a distinct class;
probably they Still laid eggs and were develop
ing only slowly their distinctive covering of
hair.
They lived away from big waters, and per-
haps in the desolate uplands, as marmots Go
now; probably they lived there beyond the
pursuit of the carnivorous dinosaurs Some
perhaps went on all-fours, some chiefly went
on their hind legs and clambered with their
fore limbs. They became fossils only so oc-
casionally that chance has not-revealed sin
gle complete skeleton in the whole vast record
Of the Mesozoic rocks by which to check
those guesses.
The Importance of Hair
These little Theriomorphs, these ancestral
mammals, developed, hair. Hairs, like feath-
ers, are long and deliberately specialized
scales. Hair is perhaps the clew to the sal
walton of the early mammals. Leading lives
upon the margin of existence, away from
the marshes and the warmth, they developed
an outer covering only second IN its warmth
holding Cor heat-resisting) powers to the
down and feathers of the arctic seabirds. And
so they held out through the age Of hard
ship between the MesoZoic and Cainozolc
ages, to which most of the true reptiles sue
cumbed.
All the main characteristics of this flora
and sea and land fauna that came to an end
with the end of the Mesozoic age were such
as were adapted to an equable climte and to
shallow and sWampy regions. But in the case
of their CainoZoic successors, both hair and
feathers gave power of resistance to variable
temperatures such as no reptile possessed, and
with it they gave a range far greater than
any animal had hitherto attained.
The range of life of the lower Palaeozoic
period was confined to warm water.
The range of life of the upper Palaeozoic
period was confined to warm water or to
warm swamps and wet ground.
The range of life of the Mesozoic period as
we know it was confined to water and fairly
low-lying valley regions under equable condi-
tions.
Meanwhile in each of these periods there
were types involuntarily extending the range
of life beyond the limits prevailing in that
PERIOD and when ages of extreme conditions
prevailed, it was these marginal types which
survived to inherit the depopulated world.
Life's Increasing Range
That perhaps is the most general statement
we can make about the story Of the geological
record; it is a story of widening range.
Glasses, genera and species of animals ap-
pear and disappear, but the range widens.
1t widens always. Life has never had so
great range as it has today. Life today, in
the form of man, gaes higher in the air than
it has ever done befUre; mans geographical
range is from pole to pole, he goes under the
water in submarines, he sounds the cold life
less darkness of the deepest seas, he burrows
into virgin levels of the rocks and in thought
and knowledge he pierces to the centar OF the
earth and reaches out to the uttermost star.
Yet in all the relics of the Mesozoic time
we find no certain memorials Of his ancestry.
His ancestors, like the ancestors of all the
kindred mammals, must have been creatures
so rare, so obscure and so remote that they
have left scarcely trace amid the abundant
vestige of the monsters that wallowed re-
joicing in the steamy air and lush vegetation
of the Mesozoic lagoons, or crawled or hoped
or fluttered over the great river pains of that
time
RIO RE CONTTNTJFD)