The copper era. (Clifton, Graham County, Ariz.) 1899-1911, 1902-05-15

GENERAL VIEW.
Geology. this science which was born with
the dawn OF the last century, teaches us how 10
interpret the history Of the earth from the
records found in the rock. II teaches Us TO
study the extinct animal forms which we find
in the sandstone and the limestone. and shows
Us how the whole and past and the present
forms one un6roken chain OF constant and grad
nal development OF animal ard vegetable life
FROM our observations we are able to show
with certainty the series of different changes
our earth has undergone, though we may not
always be able to ascertain the true causes for
the changes
The study of geology Is, of course. largely a
study of rocks. The most important thing TO
remember about rocks is that they divided
into two classes. sedimeDiary rocks, or those
: which have been deposited in water silts'
muds, sand or lime and which are therefore
usually made up of fragments of other rocks.
] Age aud pressure have hardened these deposits
7 to saudstones shalcs and limestoncs. The 9TH
cr class Is the igneous rocks. those which
have been brought up from the hot interior of
the earth as molten masses aud which have con-
| gcalcd to hard rocks near the surface. These
are called porphyry and lava Granite is ordi
narily also an igncous rock.
There are three Iorccs which cause ever active
I
Of the earth and gravtation. The first draws
the moisture from the ocean to be showered on
the mountains. Alternating heat and cold
cracks and loosens the rock on the mountain
sides. Pclting rains and rushing torrents carry
down the debris from the mountains TO the
ocean and incidentally scour their channels,
Rock after rock falls from the lofty pinnacles
of the mountains and gradually decays. Mil
lions of tons, for instance, are brought down to
the sea each year by the Gila and Colorado
rivers. Gradually but surely the mountain
ranges reduced to lower hills. the sand, clay
and debris is brought to the ocean and there de-
posted, forming new series of scdimentary
rock, sandstones lines and shalcs. So the gulf
of California. fer instance, is gradually filling
with sediments, sediments which will no doubt
one day be lifted up to mountain ranges. These
two of the active processes. Erosion tears
down mountains the sediments build up masses
of rock in other places from the debris Of the
ranges. But this is not all. The internal heat
of the earth may take hand under favorable
conditions and streams OfmOlten rock will issue
from assures in the crust: huge volcanoes will
be built up by these flows and form large
mountains as, for instance, the Cascades OF Ore
gon and Washington, and the San Francisco
mountains of Northern Arizona. The sediments
buried beneath the sea may be lifted up by
these same forces, due to the internal heat of
the earth, and the result will be lofty platcaus,
high above sea level. like those of Northern
Arizona in which the Grand Canyon is cut
corrugated and folded like Il mass of sheets of
paper into ridges and valleys like the Allegheny
mountains.
And again erosion will attack these newly
created volcanoes or uplifted mountain ranges
and tear them down again. And so in many
places cycle after cycle has gone on upbuildng
and destroying changing.
In all places we read some part of the
earth's history in the rocks. In some places
the record is fragmentary. In the Hawaiian
Islands we see only "A record of volcanic action.
In the northern part of Canada we may be able
to read only record of vast ice sheets and
glaciers covering the region.
But here near Morenci, the record is singular
ly complete; we trace, in large features, all
of the changes which the region has undergone.
Only this, the record is complex and subsequent
happenings have made it difficult to read and
interpret.
THE OLDEST ROCKS.
Long. long ago you may picture TO yourself
this country one of the low. red granite hills,
such granite rs you will see in the Chase creek
canyon above the Longfcllow Incline, or on the
Coronado mountain. do not say it is the old
which Se have any record here. You will i'm
mcdiatcly ask me how Old-and shall tell you
frankly do not know This much we can say
however that it was many million years ago, |
| shall not attempt to discuss whether twenty or
eighty millions. Streams flowed over this hily /
country, resting on the granite; in dcpressions
we find coarse hard cemcntcd gravels These
gravclS you may see for instance near the top OF
what is now Coronado mountain.
Gradually this land area sank below the sea. |
At first, while the sea was shallow and land |
was close by the wearing away of the granite |
produced sand. and this was deposited in even !
layers such You now see, hardened to sand |
stone. along the lower part of LonEfcllow In
cline and crowning Coronado mountain. form
ing fiat cap on its summit.
THE LONG PERIOD OF sEDIMENTATIoN.
And this the beginning of n long period OF
Scdimentation, of quiet resting conditions, deep |
sea conditions. The land sank below the sea
aud during untold ages the sand and mud was |
deposited on the bottom. This continued |
through what we call the silurian. Devonian
and CarbOuiferous periods. We distinguish 4
them by means of the animal remains find |
in them, differing one from another, but similar
in the same formation all the world over. The |
sea fun of animal life and their calcareous |
shells gradually built up the limcstoncs, drop /
ping down to the bottom after the death of the (
animal. Most of these shells have been obliter- /
ated by the changes the rocks have undergone /
since that time. These rocks once below the I
ocean You lind now exposed at many places /
near Morcnci.
They are shown best looking south along the |
west side of Chase creek from the top of the Long
fellow Incline. They are chiefly limestones and |
shales. piled ua in horizontal strata TO thick
ness of 500 feet. If YOU look closely you may
find at many places, but especially near the top
stratum msny shells and corals On the ridge
between Chase creek and Morenci canyon you
may perhaps find shells of primitive trilobite,
Little corals are in places found so abundantly
that veritable coral reefs must once have exist
cd here. All these animal forms are different
from those of today and of a much lower order.
There were no birds. no fourfooted animals. in
fact it is doubtful whether they could have ex-
listed in that hot, sultry atmosphere full of car
bolic acid. During the Carboniferous period
there were in the eastern part of this continent
extensive swamps covered by rank vegetation
OF low order. the remains Of which were COW
cred up by sediments and now constitute or
most valuable coal beds
The carboniferous age passed and still the
same conditions prevailed. A slight elevation
took place perhaps, and low land and islands
may have appeared above the sea but still sedi-
mentation went on. Covering Carbonifcrous
rocks we find Cretaceous shales and sandstones.
These are exposed near the Morenci water tanks
and also two three miles west OF Morenci
and in them there sra tho chnrapiarisfiC shells