Atlanta tri-weekly journal. [volume] (Atlanta, Ga.) 1920-19??, 1922-10-07

The third great division of the geological
record, the Cainozoic, opens with world al
ready physically very like the world we live
in today. Probably the day was at first still
perceptibly shorter, but the scenery had be-
come very modern in its character.
Climate was of course, undergoing
age by age, its incessant and irregular yaria-
tons; lands that are temperate today have
passed. since the Cainozoic age began, through
phases Of great warmth, intense cold and ex-
treme dryness; but the landscape, if it alter
ed, altered to nothing that cannot still be
paralleled today in some part of the world or
other.
In the place of the cyads, seqouisa and
strange conifers of the Mesozoic, the plant
names that now appear in the lists Of fossils
include birch, beech, holly, tulip trees, ivy,
sweet gum, bread fruit trees. Flowers had
developed concurrently with bees and butter
flies. Palms were now very important. Such
plants had already been in evidence in the
later levels Of the (American Cretaceous)
Mesozoic but now they dominated the scene
altogether.
Grass was becoming a great fact in the
world. Certain grasses, too, had appeared in
the later Mesozoic, but only with the Cain
ozoic period came grass plains and turf
spreading wide over world that was once
| barren stone.
The Birth of the Alps
| The period opened with long phase of
considerable warmth; then the world cooled.
And in the opening Of this third part of the
record, this Cainozoic period, a gigantic
crumpling Of the earth's crust and an up
heaval of mountain ranges; the background
of an early Cainozoic scene to be typical
should display an active volcano or so. It
| must have been an age of great earthquakes.
Biologists make certain main divisions Of
the Cainozoic period, and it will be convent
ent to name them here and to Indicate their
climate.
First comes the Eocene (dawn of recent
| life), an age of exceptional warmth in the
worlds history, isubdivided into an older and
newer Eocene; then the Oligocene (but little
o. recent life), in which the climate was still
equable. The Miocene with living species
still in a minority was the great age of
mountain building, and the general tempera-
ture was falling.
| In the Pliocene (more living than extinct
species), climate was very much as it's pres
ent phase; but with the PIeistocene Ca great
| majority of living species) there set in long
period of extreme conditions-it was the
Great Ice Age Glaciers spread from the
poles toward the equator, until England to
the Thames was covered in ice.
Thereafter to our own time came period
of partial recovery. We may be moving now
| toward warmer phase. Half a million years
hence this may be a much SUMMER and pleas
! anter world to live in than it is today.
| In the forest and following the grass over
| the Eocene plains there appeared for the
| first time variety and abundance of mann
mails. Before we proceed to any description
Of these mammals it may be we'll to note in
general terms what mammal is.
The Evolution of the Mammal
| From the appearance of the vertebrated
animals in the Lower Palaezoic Age when the
| fish first swarmed out into the sea- there has
been steady progressive development of
vertebrated creatures.
A fish is a vertebrated animal that
breathes by gills and can live only in water.
An amphibian may be described as a fish that
| has added 70 it's gill breathing the power of
| breathing air with it's swimming bladder in
| adult life, and that has also developed limbs
with five toes to them in place of the fins of
fish. A tadpole is for time fish; it be-