The Brookhaven leader. [volume] (Brookhaven, Miss.) 1883-1891, 1883-09-13
How the Mountains Grew.

The interesting question of the origin
and rise of the mountain chains has been
made the subject of more especial in
vestigation by French and American
than by English geologists. Nearly
half a century ago the late Ellie de Beau
mont gave to the world the result of his
researches, in his "Systeme des Mon
tagnes," in which he propounded an
hypothesis that still receives very gen.
eral acceptance on the continent, but
which, except in modified view, has
found few supporters in this country.
Assuming for our globe an outer solid
crust with central liquid mass, this
distinguished geologist showed that the
of its heat by radiation from its surface,
and that this process of cooling, which
has been going on at slow rate from
the earliest geological times, causes the
central mass to contract and lessen in
volume. This lessening of the heated
nucleus has led the crust to comfort
itself in order to fit or adapt itself to
the diminished volume of the central
nucleus, causing the crust to wrinkle or
fold in great corrugationS or to fract-
ure, and the fractured edges to squeeze
up in lines of mountain chains.
He showed that mountain chains have
been formed at all geological periods,
and that their relative age could be as
certained by determining the age of the
tilted mountain strata, and the age Of
those strata which abut horizontally
against their base. For it is evident
that the mountain range must have
been elevated before the deposition of
the strata which lie horizontally at their
base, and which are unaffected by the
disturbance that threw up the mount
aims. 1t follows, therefore, that the
mountain chain is older than the hori-
Zontal strata and newer than the up
heaved strata. Thus the age of any
mountain range is easily determined,
relatively to the successive groups of
strata forming the sedimentary series.
Ele de Beaumont further argued that
as the crust of the earth must have be-
come thicker by secular refrigeration it
follows that the crust was thinner and
less strong ut the earlier period of the
earth's history than of the later periods,
and, consequently, that the crumplings
and mountain chains, although more
frequent, were not on so large a scale in
early geological times as when the crust
had become thicker and more rigid.
But although there is no doubt that
some of the oldest mountains are very
insignificant in height, we have no
means of knowing what their original
altitude was or how much of their mass
has been removed by wear and denuda-
ton. Some of the hills in the neigh
borhood of St. Davis, in South Wales,
are neither majestic nor lofty, yet they
are among the earliest of our mountain
ranges.
Or look, again, at a range of hills
of much later date, vet still very old, as
for example, at the Mendips in our own
country, and the Ardennes in Belgium,
both portions of the same mountain
chain, raised before the formation of
our Oolitic hills of Bath and Chelten-
ham, or of the Lias cliffs or Lyme
Regis. 1t is possible that this range,
which is now of comparative insignifi-
canoe in no case attaining a height of
1000 feet in either England or Belgium
formed at one time lofty mountain
chain. For, Judging from the portions
that are wanting and have been re-
moved from the Mendips, it has been
estimated that those hills may at one
time have had an elevation of not less
than 5000 to 5000 feet above the plains
of Somersetshire. while the Belgian ge-
ologists have shown that the Ardennes
might have scared from $4,000 to 49,
900 feet above the plains of Belgium.
This chain, now so unimportant, may
at one time have We'd with the later
formed Alps and Apennlnes in height
and gsandeur. How strange and strik-
a picture our corner of Western Eu-
rope must have presented to that early
age, when the English Channel was not,
and when a great chain of mountains,
possibly snow-capped, ranged from the
Mendips to Westphalia! The portions
which remain are, as it were, the worn
down stumps of this great mountain
chain, the whole of the vast superin-
cumbent mass having been removed by
wear and denudation continued through
long geological times. And such has
been the case in many other mountain
regions of our globe; on the one hand
reformation being produced by subter-
ranean forces, and on the other planning
down and levelling by meteorological
agencies--GOOd Words.