The silver messenger. (Challis, Idaho) 1890-1912, 1898-02-01

tAaoic and Ezoio System Of Rocks.l

hO GAVIN CephihS iiAOiOoo
are the first known stratafied
rocks, their chief interest being,
that they are the Oldest.
They contain no known fossils
of any kind, are highly metamor-
phic, and crumpled. They are
found in the axis of very high
mountains, and occur in small
bodies, in Canada, and the east
ern states, Labrador is nearly
all Azoic. Wherever the Azoic
may be found, it is a sure evil
dence of great erosion and age.
Their thickness is not uniform
sometimes they are only 40 or so
feet thick then again they will
be found two or three thousand
feet in thickness, they are most
ly of chrystaline texture, quartz
ties, gnisses, etc. They are sup
posed to contain no life, though
there has been found in them
some curious forms that some
scientists think are the petrified
remains of the compound Proto-
zoia, Eozoon Dawn animaD, and
it has been suggested that the
Azoic and Ezoic be consolidated,
into one series to be called the
Protozoic, or First Life.
The Ezoic-Dawn of Life
This formation lying unconform-
ably on the Azoic, contains the
first known specimen of life, that
are undisputed. Here the Pro
tozoia fourishes in great numb
ers, also club MOSES (the Lyco-
podium), and several kinds of
ferns have been found and class
flied, but the history of this sys-
tenn is very meager, taking the
entire system we have but seven
kinds of living things, as yet
discovered, and of them so little
is known that no one can write
a very clear or comprehensive
article of them.
The rock system is very little
different from that of the Azoic,
quartzites and gnisses, metamor-
phic shales, etc., are the leading
features. There seems to have
been one of the greatest changes
at the end of this age, that has
ever been in the history of the
world. Between the Paleozoic
and the Ezoic is the "lost inter
val" of geological history, of the
history of the world in that in
terval we know nothing, but the
changes that took place were
vast and sweeping. When the
Eozoic ended there were but few
forms of life. When the Paleo
zoic begins there was quite a
diversified fauna and fora, near
ly all that great family, the in
vertebrates are represented in
the first of the Paleozic Age.
The Paleozic Age is divided
into three great divisions as car
be seen in the chart in our pre-
ceding article.
The Silurian-or Age of Mol
usca; the Devonian-or Age Of
fishes-the Carboniferous-ol
Age of Amphybians and Aero
gen plants.
The Silurian is peculiarly in.
teresting for it's vast amount o.
shells from which it is named
nearly the entire system is lime
stone, though there are stratas
of sandstones intervening be-
tween the greater stratas Of
limestones.
Animal Life-Corals are very
abundant. There are several
kinds, of which we will mention
a few of the leading ones, cur
corals-(Cyathophylloids); hon.
ey-combed corals (Favostids)
chain corals (Halysitids).
Hydrosa-In still pools ano
sheltered bays and inlets, grew
q fine feathery thing like horse
hair-the Graptolite. This ami
NAL was characteristic of the
Silurian, and can be recognized
wherever seen. Any one car
identify the Silurian by this
animal, when they have become
familiar with it's form.
Echinoderms Crinoids. "A
crinoid was pear-shaped body
set on stem. with sometimes
many plumose arms; sometimes
few arms and sometimes no arms
at all.
Molusks-Brachiopods- Biva,
I've shells are dividee into main
groups. The Lamp shells.
lBrachiopods) and the common
Bivalye, Uamellibranchs), al
present the latter are extremely
common, while in the Siluriar
Age they were very rare. An
other great family were the Orth