The Bossier banner. [volume] (Bellevue, Bossier Parish, La.) 1859-1952, 1876-02-01


even below the level of the original val
leys, and the latter become the elevations.
This can be proved by noticing that the
strata visible on the sides of most valleys
and hills are not parallel to the sides, but
are nearly at right angles to them.
The mountains formed by depressions
OF the crust were far more common in the
early history of sedimentary deposit, for
the crust was then comparatively thin,
and hence more yielding to lateral press
ure. But after the crust became thick
ened beneath by the cooling of the earth,
and more rigid by the accumulation of
strata above and by previous plication
and solidifcation, the mountains formed
were largely due to uplifts of very wide
extent carrying the stratified deposits
with them. Our Rocky Mountain sys-
tenn was formed by these uplifts in the
tertiary age, and it is probable that coral
island subsidences in the Pacific Ocean
accompanied the continental elevations.
The adherents to the accumulation
theory-among whom are Hall and Hunt
on this continent, and Scrope and Lyell
in Europe-haye noticed that in noun
famous districts the elevations are less
than the aggregate thickness of the strata,
while in non-mountainous sections the
heights correspond to the thickness of the
strata. If the latter were equally true
in mountainousdist the Appalachian
Mountains would attain height of 49,
900 feet. Mr.. Hall holds that these bar
riers are due to original deposition of
materials and not to any subsequent
forces breaking up or disturbing the strata
of which it is composed; and that up
heavals and contortions of strata are only
accidental and local. In this view he is
sustained by Montlosier and Jukes. He
also claims that the direction of mountain
elevations is determined by accumula-
tions along the sides of oceanic currents
or shore lines. Dana, on the other hand,
considers the northeast and northwest
trends of most of the mountain and shore
lines on the globe to be the result o1
cleavage in the earth's crust, and to in.
dicate lines of weakest cohesion, like
cleavage planes in crystals. ss3
| The accumulation theory supposes that
after vast amount of material has beer
deposited in successive strata under watel
a great continental upheayal brings thu
whole mass high and dry above the watel
line; and the present mountains are th'
stratified deposits which have escapet
denudation by the action of frosts ane
floods. We have good illustrations o
this process of erosion in the Missouri
River valley, where the elevated land ]
! being constantly washed away, forming
deep ravines and abrupt ridges, and j
carried into the muddy Missouri and de
posted in the deltas at the mouth Of tn
Mississippi, thus adding constantly to tn
territory of Louisiana. AS Egypt is sai'
to be gift of the Nile, 50 Louisiana is
gift of the Missouri. The effects of ere
sion on small scale can be seen on tn
sides of deep railroad cuts, where minis
ture mountains and valleys are forme
/ by the washing of water as it runs dow
their slopes *e t"'@
/ Prof. lie Conte opines that these OK
: posing theories result from the loose us
I of the word mountain. He treats tn
! whole subject under the two heads {
mountain formation and mountain sculI
, ture, and claims that the true m0untai
!, chain or the convex plateau which Col
stitutes it is due only to holdings Of th
crust, and that those elevations which al
} left by the erosive action Of water are nc
/. mountains but simply sculptured cont
E mental elevations. e aa e
IL The effect of shrinkage and of erosio
!, can be fairly seen, on small scale, by til
following artificial contrivance: Take
. wellfilled bladder, or toy rubber balloon
: and cover it completely with sever
e successive coatings Of tallow, glue, plastt
9 of Paris, or other substances that wi
0 harden after they have been put on in
E plastic state. These will represent IL
= stratiged crust. Then, by withdrawn
: some of the air from the bladder, whic
q will answer to contraction of the nucleu
J. the crust will become rigid, furrowed ar
y. fractured by lateral pressure, like Il
III crust of the earth Now, by allowing
# well-regulated stream of water to flo
) over the surface of this, We can see maj
e of the phenomena of erosion, like tho
apparent on the earth surface. Scients
It Americdn. s.
Q THE list of directors and members
the American Tract Society contains 3
e 600 names. Itwas established in 18s
e It now publishes two weekly and TO
t, monthly papers, with an annual aggl
It gate circulation OF 5000, 900. During
n career it has issued 9,679 distinct pub
I, cations, Of which 1,732 are volumes.
a has printed 523, 3,O97 1888 copies Of pub