The Salt Lake herald. [volume] (Salt Lake City [Utah]) 1870-1909, 1899-07-12
=. THE HERALD'S
Home Study Circle.
Copyright, 1898. by Seymour Eaton.)
Directed by Prof. Seymour Eaton.

| and again over extensive regions been
rent and torn, portions thrust up above
the sea, others cast down, whole pla-
| teauS and mountain chains have been
| formed, only to be worn down and
erased, the roots OF the mountains and
fragments of fossiliferous strata being
| left here and there to tell the tale of
creation and destruction, of rejuvena-
ton and OF senescence. One of the
| grandest results of modern geology is
| the history, now fairly well worked out,
of the revolutions which have taken
place in our own continent.
| 1t should be borne in mind that these
great changes, widespread and pro-
found as they were, extended through
| long ages. There were immensely long
| periods of quiet preparation, during
| which there was slow accumulation
, of beds at the ocean bottom, formed
of material borne down to the sea by
rivers rising in the highlands of the in
| terror. These periods were succeeded
by crises of periods of slow upheaval.
Nature has taken her time for all this
work. The length of time which elapsed
between the period when our planet be-
came fitted for the existence of the
simplest plants and animals and the
Cambrian period of biologists has been
estimated at from 35,000,000 to 10000, 900
years.
1t 10 pTODdDit lletI THESE CH1NSeS
went on more rapidly than now, and
that consequently the evolution of or
ganic types was more rapidly accom-
plished and more thorough-going than
in later times.
Sir William Thompson, now Lord
Cayley, insisted that 1.-The world at a
very early period was subjected to
more rapid and violent changes in it's
physical conditions than those now Oc-
nd oh
tended to induce changes at a CORE
spending rate in the organisms which
then existed"
We now pass on to a much later pc
Rod in geological history; that of the
appalachian revolution, when the APP
palanchian mountains were formed,
and there were corresponding changes
throughout the globe. This was, from
a biological point of view, the most
notable event in the history of our
earth, unless we except the appearance
of man. In its effects on life, whether
direct or indirect, it was of vast signi-
ficance; for contemporaneouS with and
as a consequence of this revolution was
the incoming of the new types of higher
or terrestrial observation-disclosures with
limbs and lungs, such as salamanders
and the like, with reptiles, birds and
beasts.
Since the Appalachian ranges were
upheaved and carved by rivers into
mountain peaks, at the close of what
biologists call the paleozois age, there
have been great changes of level and
physical geography over our Atlantic
coast region. The mountain region was
worn down to almost plain, with a
broken surface like that of New Eng
land at present. Then the region was
again upheaved and tilted up, and the
rivers running more rapidly cut deep
channels through the plateau, and
mountains were thus formed. Several
successive cycles of unheaval and wear
ing down have taken place from the
close of the paleozoic era to the present
day.
Now. all these changes in physical
geography must have caused much
variation in animal life. At the time
when reptiles, birds and beasts, or
manuals, appeared, onr Atlantic Dor
der presented different climatic zones;
from tropical lowlands, with their vast
swamps, to temperate uplands, stretch
ing up, perhaps, to Alpine SUBMITS,
with possibly glaciers of limited extent
filling the upper parts of the mountain
valleys. New Zealand at the present
day has sub-tropical belt if tree ferns,
while the mountains towering above
have near their SUBMITS fields of ice
and glaciers. In Mexico only about 20
degrees from the equator is the tenn
perate plateau rising above the tropical
belt, and farther up the sub-Alpine
snow-clad peaks of Popocatepete and
Orizaba- So in the Appalachians of the
paleoZoic age, the cryptogamous for
eStS and their animal life may have
been confined to the coastal plains and
lowlands, While on the higher. cooler
levels may have existed the different
assemblage of creatures.
nd mi aTc-
out Of existence by subsequent changes.
and new assemblages better adapted
to the novel climatic and geographical
conditions took their place. Besides the
changes in the shape and contour of the
land. the extinction of certain forms
was undoubtedly aided by the struggle
for existence or competition. Thus
during the age of reptiles these crea-
lures dominated the earth and sea. 1t
took long time for the birds and
beasts, after certain lowly forms ap-
peared, to gain n foothOld. Competi-
ton drove the bird type to live in the
air, and the mammals burrowed in the
earth, lived in trees or ran over plains
less frequented by reptiles. At least, in
Il way not yet understood, the reptiles
in part died out and were replaced by
the more intelligent types of birds and
mammals.
When we come to the ice period we
readily see what a widespread influence
a change of climate had on living
beings. The extinctions and migrations
which took place at the time man ap-
peared are well known and illustrate
in way every one can appreciate how
profound and immediate geological
changes have been in causing the origin
of life forms.
R.0