Grant County herald. [volume] (Lancaster, Wis.) 1850-1968, 1913-12-10
Under The OCEAN
Changes In the Sea Floor From
Shore to Shore.
THE BIG MID-ATLANTIC RIDGE.

1t Starts at Iceland and 5isects the
Ocean Down Almost to Cape Horn.
In Places 1t Rises Above the Surface,
Forming Groups of islands.
A sketch of the landscape" OF the
ocean bed IS given by DC. A. e. Ship
ley in an article in the Edinburgh Re
view:
The passengers and the crew OF q
liner racing over the surface Of the
Atlantic are apt to imagine that under
them is q vast layer Of water Of vary
ing depth sparSely inhabited by q few
fish As matter of fact, the whole OF
this great ocean is teeming with life.
If instead of taking ship we could take
to the water and walk across the BED
of the Atlantic to America, starting
from the shores of western Europe, we
should in effect be travelling through a
succession of new countries. Not only
would the surrounding physical cOndi-
tons vary as we advanced, but the
animal and plant life would vary in
correlation with the altering physical
conditions.
Walking farther and farther toward
the depths Of the Atlantic, we should
soon lose all sight of the aIgae, and the
shallow water fiSh-the pddice and sole,
whiting, skates, dogfi6h and others and
cod-wOuld give way to the megrim
and the bake The sea floor woald
gradually change from rock or gravel
~fn de- Ia
mud or OOZes of VEsz4O1S tints, theiAr
original colOrs often modified by the
action Of the decomposition Of organic
particles in them and on them. All
these finer deposits are derived from
the neishbering land and are blown
seaward by Offshore winds or washed
down by rains and streams and carried
out TO the sea by rivers.
THE distance to which fine matter in
suspension may be carried is very
great. The KOngo is said to carry it's
characteristic mud as far out to sea as
600 miles. and the GangeS and the
Indus as far as 1000 miles
Except in the neighbOrhood of such
great rivers subaqueOus traveller
would soon pass beyond what Sir John
Murray has called the mud line a
line that limits the terrigenous deposits
everywhere surrounding dry land.
Having reached this limit, we must
proceed wariIy, for at the mud line,
at an average depth of q hundred
fathoms, we shall find ourselves at the
edge of the continental shelf. that rim
which extends seward to a varying
distance from all land areas. the rim
on which Great Britain rests. Beyond
lies the continental slope. a precipice
more or less abrupt and more or less
high. descending by steep declines or
terraced cliffs until depths of 1000
fathoms are reached. --------,-z-sssaHssSSssssa
'The Atlantic, Compared with the
other great oceans. has an unusually
large area of comparatively shallow
water. Of it's total area 27.5 per cent
is covered by water less than 1000
fathoms deep; IS per cent lies between
1000 and 1900 fathoms and Al per cent
between 1000 and. 1900 fathoms; the
remaining rs per cent is still deeper.
Eat the foot of the continental slope
lies an illimitable plain of a uniform
dull. grayish buff color, fat and fea-
tureless as the desert. and only diYerSi-
fed by an occasional as yet uncovered
rock or wreck or the straight line Of q
recently laid cable. This plain con-
tinues with scarcely a change in seen
cry or in level until we approach the
great mid-Atlantic ridge. As Bruce
has shown. this ridge. which roughly
biSectS the Atlantic, extends from Ice
land as far south as fifty-three degrees
of south latitude. with slight and
quite inexpiicable break just under the
equator. The ridge runs almost parallel
with the eastern contour Of North and
South America, which. in turn. as the
ordinary map will show, roughly cor
responds with the western contour OF
Europe and Africa. From time to time
the ridge rises above the surface Of the
water, as in the Azores group. st.
Paurs rocks, Ascension. Tristan da
CGnha and Cough island.
Having assembled the eastern and
descended the western slope of this
mid-Atlantic ridge. we should again
traverse plains of grayish oOze far
more extensive than any level land
tract known to geographers. and as we
approached the American coast we
should gradually pass through. in re
verse order, the zones of life traversed
when leaving Europe. On the eastern
coast OF America the slope is much
more gradual than on the western
coast of southern Europe and Africa
ExnArience