The Ekalaka eagle. [volume] (Ekalaka, Mont.) 1909-1920, 1909-10-08
MYSTERIES OF NATURE /
BY George Frederick Wright, {
A. r., IL. D. {
Continent Tilted Up and Down 5


The level of the ocean is more con-
slant than that of the land. The ex-
panse OF the ocean is three times as
great as that of the land, and it's
depth more than ten times as great.
If all the lane should be sunk in the
ocean,. it would raise the general wa
ter level only about 800 feet. In.
general we may say with perfect con
fidence that the ocean beds represent
portions of the earth's crust which
AVE been sinking from the earliest
geological times, while the continents
represent those portions which. with
many oscillations, have, on the whole,
been rising. 1t probably is not true,
as is often stated, that the areas of
lane and water have shifted places
in past time, so that continents were
found where the main ocean beds
now lie, and oceans swept without in
terruptiOn over the continental areas.
Still there is the best of evidence that
large portions of the existing on
tinents were at various times below
the level of the sea.
But. while this is true, it seems
equally certain that during the subsi-
dence Of these areas below the sea
level, they existed either as shallow
water. borders of the main continental
areas or as internal seas. For ex-
ample, the great depth of sedimentary
rocks which cover the Mississippi
basin, extending from the Allegheny
mountains to the Rocky mountains,
are shallow-water deposits. So shall
low, indeed, was the water during long
periods that it was little more thar a
swamp in which the vegetation that
formed the numerous seams of coal
could grow and flourish. But the level
was not constant. After a large &C.
emulation of vegetable matter that
could be turned into coal had taken
place, there was a slight and very
gentle sinking of the whole area, so
that mud and sand were brought in
from the neighboring higher lands to
form a complete covering for the coal;
so that when it was turned into rock
it was able to protect it, and preserve
it for future ages. This process of
slow but irregular sinking of the Mis-
sissippi basin continued until thou
sands of feet Of ~sedimentary material
had been washed into it, as the Mis-
sissippi is carrying sediment into the
Gulf of Mexico at the present time.
These successive strata, like the
leaves of a book, record the various
downward movements of the long coal
period. In other countries, especially
in England and China, there is the
same record of long-continued down
ward movements of continental areas
during the coal period.
If this downward movement had
continued always, the coal would
have been inaccessible beneath the
depths of the sea, where, indeed, much
of 1t does still remain. In Nova
Scotia the best seams of coal are
mined many miles and at a depth of
many hundred feet below the bottom
of the sea. In England also some of
the best seams of coal are followed
out underneath the sea, and it is sup
posed that coal veins are continuous
from southern England to the con-
tinent far beneath the bottom of
Dover strait. But fortunately the
downward motion of the coal area was
in due time arrested, and the contrary
movement begun, which has brought
this priceless material within easy
reach of men in the mountains of
Pennsylvania and China, in the hills
of England and in the plateaux of the
central and western states of Amer
lea. Other illustrations of great
changes in land levels are too
numerous to be mentioned in detail.
In Colorado there was a gradual sub
sidence of land below sea level during
the carboniierous and @cretaceOns eras
until from $4,000 to $4,000 feet of
sediment had accumulated over the
sinking area. But at the end Of that
period the area began to rise, and this
rise has continued until the present
time, when it stands many thousand
feet above the level of the sea.
Similar witness to such changes of
level is borne by extensive sediment
airy rocks containing abundant sea
shells of late geological age, which are
found at a height of 10000 feet above
the sea on the P%yrenees, the Alps and
the Caucasus mountains, and at q
height of IA 1000 feet upon the noun
tafns of central Asia. A map of the
eastern continent during the early
part of the tertiary period shows a
great Mediterranean sea covering all
central Europe and extending into