Memphis daily appeal. [volume] (Memphis, Tenn.) 1847-1886, 1867-02-20

i place is well understood by geOlOglst
and yet I fear that might not explail
? With sEfi icH precisio5, The mode
formation Of the valley did not make
few statements with reference 10 the,
, uphesvals. While our earth was c0olin
rom this state OF primal igneous fusiH
il naturally shrank, for every body know
that materials in a state of heat al
larger than when cooled. A bar Of irO
. red not is larger than the same bar vine
cooled, for it stretches when it is heate
3 and contracts when il is cooled. Now
suppose our earth cooling; the materia
of which il consists in contracting -th
crust up0n its su~face-wiil necessaTil
collapse IN consequence OF its subsidence
&c Will shrivel, it will fold itself. an
these folds form Irregularities, and thes
irregularities, pressing on the material
below, which are still in a state Of igne
aus fusion, determine a flow from withil
Of these materials which may bUrs
through the crust of the earth and caus
all sorts Of disruptious and irregularities
Our mountain chains are nothing bU
these upheavals, or this outward pres
sure of melted materials finding thei
way through the solidified crust, which
in consequence of the shrinking of tn
surface, is thrown into wrinkles ant
forms al sorts of irregularities. Zap
plaUse. We can trace this, and tner,
are some traGta OF our country ard o
Europe in which all the details Of thi
formation Of mountains have been ascer
tanned with a mathematical precision
The first data concerning this mode o
formation of mountains were traced bl
the greatest geOlOgist of our age in ia,
Jura mountains. There are facts ther,
n.na 4
OF our earth with such nca ness and ac
cUracy that those mouutairs may bi
considered as u geological museum to al
who may visit them. any one who ha,
/ crossed them must understand how
mountains are formed, because the facts
there are so plain that their evidence
is incOntTOvertible. The lecturer
drew sketch on the blackboard
F placed on the platform 70 illustrate the
formation ana pOsluon OF strata IN thj
J Jura mountains. suppose you start al
the foot and follow the inequalities of the
mountains; yOH ascend that slope 10 the
hight Of 3, $40 feet, you 20 down the OppO-
site slope, you cross this valley; you as
cend this other slope to the hight Of per
baps iUrJ feet; then ycu go down That
other slope into this valley, and then rise
again. In 20 doing you may remain
upon one and the same bed. and you may
have the evidence that it is one and the
same bed by going with ihe transverse
valleys or assures which extend across
these mountain chains There is fup-
ture across two OF the mountain chains.
through which a aew Fogd has been laid
and right and left OF the road you gan see
the formation Of these mountains 10 the
very base, SO that you have sections. as
geologists call them-diagrams OF the
internal structure of these noun
tains. In this manner it is plain that
these bells have been folded as ! haze
stated for no water containing loose
materials in suspension can deposit them
otherwise than i'm horizontal beds. Take
a bowl titled with muddy wafer aud let
it subside and il will folm a horizontal
deposit at the bottom. Examine 1T the
mouth of q river. or place where loose
materials are carried into lake and you
will end ihat they have settled in q hori-
zontGl deposit, one deposit ON tGp ~ the
other. 80 geolOgists know that when
ever strata or beds Of rocks are in any
position different from that of huriZon-
talty ID is in consequence Of q distur-
banca 10 which thev have been submit
ted at a LATER time, and he change % the
beds 10 any given extent from the hori-
Z0ntai is the measure of the change
which any neds. nave undergone since
the time they were formed. That being
the case, we must admit that in the Jura
all these beds were once horizontal, and
that they folded into ihis manner bv
some cause or other. Now, that cause
may he twOfold. Ii may be a pressure
from below at each Of these bulg-
ing highs, "a IL mag % . press
ure from tie side causing ruilles to be
made, just as would be made in a piece
of paper or pasteboard which was pressed
with sufficient energy from one side
and which rOHld srln itssif, anu u it was
long enough, would arch itself repeat
ediy. Now, then the question is, which
of these causes has produced the chain
in the lura is lt $ pressure ifom The
side, or is il a pressure rom below. We
can answer tliat it is Goth. We have
evidence of ld.eral pressure at one time
We have the evidence of pressure from
below at another time. Here aud there
We have materials OF that kind which
indicate that they were in "a stale of
igneous fusion that they burst through
materials WHICH are in regular strata,
slopiBg IN an opposite direction upon the
side of these massive rocks In the center.
Now that is direct evidence that at
one time these beds were in horizontal
position that materials in . STATE of
igneous fusion nave bSpken through them
and caused them 10 slant in opposite
directions. But where there is q sue
cessiOn of wrinkles, 50 to speak, gradu-
ally fading away in the distance, as,
for iHstsHre, ia The Alps, where there
are nights of six Thousand or more feet,
and that gradually fall towards tie west
towards burgundy, they are mere updu-
latiOns, aud when we see that the slopes
are sleeper on the side which faces the
Alps than on the opposite, it becomes
plain that tie lateral pressure has pro-
duced. at least, some Of the features of
these inequalities. This gives US an ex.
PLANTATION Of the mechanical agency, hu
does not give Hs tho element of time.
The table land OF Guiana exhibits masses /
of granite, on TIE slope Of which there is
gneiss, mica states, and clay states which
are strauligd ROCKS consolidated by
internal heat and raised by in
ternal pressure. I wish / had two or
three hours TO explain this subject. but
/ must rondense. rhe lecturer then ex-
planned that the lowest strata is the
oldest, and the uppermost the youngest,
and also the manner in which il WAS de-
termincd, what strata were deposited on
different parts of the earth at similar
periods, and what these periods were.
As an antiquarian 10y looking at coin
knows 20 what era OF history it !
belongs, so the geologist and the anato-
mist looking at a shell or a bone Of an
animal, or a petriiied portion of plant
deposited in some strata OF the a9r:h's
surface immediately knaws to what Pc
riod that portion Of strata belongs. In
this way the strata Of deposits on the
earth's surface have been divided into
periods. The oldest period at which no
animal or vegetable life existed is called
the ayOio. Then We nave the silurian,
then the qeVonian, then the earbonife- |
rous. II is to that system that the beds
which contain our coal belong Then |
we have tiassic, then .he juarissie, then
the cretaceOus, then the eOcene, then the |
mi0cene, then the pliocene, and upon
that are found the deposits which are ac-
cumulanng at this very moment. The |
study OF geology in its present form con-
sists in the investigation Of these differ |
ent conditions, and the geologists begin |
to pursue these Studies in the same man /
ner a. historians, and their studies are |
limited to particular epochs, and to |
particular portions of the surface of the ]
earth. we know that the deposits 1
of New Jersey were formed at |
the same time that the deposits |
in Europe were accumulated, and |
the whole has received the name of |
the cretaceous, because Of the fact that
white chalk belongs to that period. |
Now how is this recognized? BY certain |
animals which are always found in these |
beds, Just as sand and clay Of the pres |
ent period could easily he distinguished /
rom sand and clay of another period. !
from the fact that in the clay Of the |
present day there would be certain shells 1
found. The common clam extends not
only along the American coast Of the |
Atlantic, but also along the European |
coast. Now, deposit of clay formed |
now a-days upon the shores of the At !
laDtic, whether upon the American or
European coast, would be recognized by |
geologisis as Of the same period by the |
,,reaa.nca of a clam and so il is that hv l