Chicago eagle. [volume] (Chicago, Ill.) 1889-19??, 1893-08-19
THE AGE { F MAMMALS.
SliOW THE EARTH LOOKED BE
n FORE THE AGE OF MAN.

Gradual Attainment of the Earth's
Present Outlines Wonders of the
Tertiary Age-The Mammoth AMI
mails Which Once Roamed Over
North America.
With the tertiary age, or the age of
mammals, modern history of geological
times began During this age the North
American continent gradually attained
its present geographical outlines. As
the continent, especially its western por
ton. continued to rise above the level Of
the ocean, the great sea of the cretaceous
period. which extended from the Mex
lean Gulf toward the Arctic Ocean, ut
first became vast inlaLd sea. Suisse
&uently. rs the elevation of land contin-
I'D, this great sea was gradually broken
up into several great lakes, existing be-
tween Western Dakota, Nebraska, Kan
sas and Texas and Eastern Oregon and
Southeastern California Further up
lifting of the western portion of the con-
tinent gradually caused also these lakes,
with few exceptions, as, for instance,
the Great Salt Lake, to disappear. The
Columbia Colorado, Missouri, and sew
eral other western branches of the Mis-
sissippi gradually carried the waters of
these lakes to the oceans, and ''the great
American DESERT on both sides of the
Rocky Mountains remained to tell the
tale
Thus the staked plains of Texas and
New Mexico, the Bad Lands of South
western Dakota, the deserts of Eastern
O.Sgon, Nevada, Arizona and South
n@stern California, and some other
T'alkali flats" of our Western States are
the legacy left by the great cretaceous
sea.
The famous canyons of the Colorado
and some other Western rivers, the re-
markabe mesas, or table lands of the
American deserts, the numerous terraces
of plateau and the often remarkable fan
tastic formations resembling towers,
castles, Notifications and the like met
with in some localities of these regions,
are also to some extent due to the great
cretaceous sea. This, with its succeed
ing lakes, had, in course of time, de-
posted immensely deep layers of CON-
paratively soft sands and clays, through
which water, from rivers and rains,
= gradually made its way in various direc-
lions, cutting deep channels, occasionally
from 5000 to more than 5000 feet deep,
washing away vast areas of strata and
leaving only some curiOusly shaped ter
raced plateau, pillows, cones or hills
standing.
The gradual uplifting of the entire
western half of North America continued
to 20 on during the tertiary age, which
succeeded the cretaceous period. Dur
ing this age the coast chain was elevated,
and through assures of the Sierra and
4 Cascade ranges vast lava floods were
poured out over great portions of North
ern California, Oregon, Washington and
to considerable distance into British
America, covering an area of 800 miles
long and 100 wide, with lava which in
some locations is from 1000 to 5000
deep These lava floods are considered
to have been the most extensive known.
The great elevation of the western
portion of the continent since the creta-
ceous period, and the consequent grad
ual disappearance of the great cretaceous
sea naturally brought about some i'm
portant changes of climate. Still this
remained considerably warmer than it is
at present About the beginning of the
tertiary age the climate of the present
Northern Dakota, as is inferred from
the palms, figs and other plants
then growing there, was similar t.
that of Southern Louisiana or Flori
da at present. And about thu
middle of this age magnolias and othe
plants now flourishing only in Southern
swamps and forests still prospered IL
Greenland. And towards the close o
this age elephants, rhinoceroses and othe
animals which at present live only in fal
more southern countries still swarmeC
about the Upper Missouri Yet with tn
tertiary age began the modern geological
history of our globe. During the sam
the geographical outlines of our contin
ent were substantially completed, an,
the plants and animals gradually put O
q modern appearance. Now for the frs
time perfectly Towering plants tlourished
Now oaks, naples, palms and other tree
of modern type became abundant. NOV
butterflies, bees and other flower-loyin
insects began to swarm, and true or pei
feet mammals, both herbivores and cal
nivores (plant and flesh cating), as rhi
noceroscs, camels, elephants, deer, dog,
cats, horses and monkeys, besides bird
of modern type, as owls. eagles, wood
peckers, ETC., made meadows and forest
ring with life.
The wide geographical distribution o
both plants and animals of the sam
general kinds during this age indicat
that Asia, Africa, Europe and Americ
were then connected with one anothe
by land. Africa was connected wit
Europe by an isthmus over the presen
Straits Of Gibraltar, and by anothe
isthmus with Italy, as the numerou
fossil remains of elephants, hippopot
ami and other animals now living onl
in Africa, found in the caves Of Malt
Sicily and Spain, Indicate Asia wa
connected with Africa by the isthmus @
Suez; America was connected with Asi
10y an isthmus over the present Behrin
Strait md perhaps with Europe owe
Greenland, Iceland, the Faroc and III
British Islands,
Long before the tertiary age begi
Australia bad become permanently sepaI
ated hy water from the other continents
az the absence Of all higher mammalia