The mirror. (Stillwater, Minn.) 1894-1925, 1915-03-04

tural similarities in common with
the. bird; resembling somewhat the
, kangaroo.
, The Juriassic age was one of ex-
pansion and realignment in the west
ern hemisphere. and of we'll nigh
complete submergence in the eastern
AS the Appalachian geosycline
gave way under the enormous weight
OF its contained strata, throwing
up the Appalachian mountains. so in
the Jurassic age the Sierra Nevada
geosycline yielding to the weight of
It's contained sediment gave way.
rssulting in the uplift of those
!; mountains. No better idea can be
gained of the vast space of time con-
stituting but one small part of the
earths history, than from the fact that
during this period, the Appalach-
ian mountains upheaved in the pre-
vious age. were worn by the slow
process of weathering to range of
hills. to be again raised into mount
aims. Plant life was abundant. New
types are recognized and old ones
become extinct. Marine life was
varied and abundant.
i The Jurasslc age was the high
water-mark of reptilian develop
ment. Here gigantic bat-!ike Pter-
osauria navigated the air. Plesiosaurs
swan the sea and huge armored
Mosasaurla rvamed the land.
In the age preceding the era in
which we live, what were the out
lines of the North American Cont
inent? Beginning at the east, the old
Palaeozoic land extended an un
known distance eastward, toward
Europe, and westward a short dis
tance beyond the present Allegheny
mountains, including portions Of
the Cincinnati AnticlIne and that
upheaved in the Devonion age. The
Colorado Island and ridge, or back
bone running diagonaly across the
western edge of the continental
block, fringed, by rocky islet reef
which later were to become the
Coast Range, Between great in
land marshy sea extending from the
Gulf of Mexico to the Arctic Ocean,
OF which the Mackenzie river is the
shrunken remnant
Vast spaces of time have teen
passed over or compressed into the
single term ages" with no mention
made of the wide differentiation be-
tween the floras and faunas as seen
in the almost numberless series, re-
sulting from crustal movements, In
a single age. Only few of the widest
and most radical changes have been
referred to as IN historic times we
speak of the century alone as the
guide post.
The Cretaceous age is full of rec
ords, not only stratagraphical, but
of plant and animal life as well. No
age saw greater nor more widespread
submergence than this. The deposit
ion of it's strata varies from a few
feet to 10000 feet in thickness and
forms greater part of the uplift in
the Rocky Mountain Cordillera.
Twice during the age. Mexico and
Southern United States was sub
merged, extending the Gulf of Mex
leo half way up to the Great Lakes.
ond twice uplifted to substantially
its present form. During the periods
Of submergence vast erea was COW
cred with fan shaped wedge of sedi-
ment varying from a few feet to
10000 feet in thickness.
Throughout the west large fresh
water seas were formed in whose
beds veritable museums of plant and
animal life have been preserved.
Most of all is the cretaceous no.
table for its plant development; here
OLD forms have become extinct and
new types are introduced. Instead
of the Cactus like forests Of Polaez-
oic time modern forests trees, have
taken their place. Marine life had
undergone great changes.
The passage of the Msssozoic age
was marked by a season of intense
Crustal movements and volcanic ac-
tivity resulting in the uplift of the
Rocky Mountain system and the re-
establishment of substantially the
present alignment of the North
American Continent, after which fur
ther deposition consists of interior
fresh water deposits and marine de-
posits along the coast and the Andes
in South America from Columbia TO
Cape Horn.
The cataclysim which marks the
passage of the Messozoic in the
Western Hemisphere seems to have
inaugurated widespread changes
in the eastern. For at the beginning
Il a