The Saint Paul globe. (St. Paul, Minn.) 1896-1905, 1899-10-30


miles, being about 1000 feet more below
the level of the sea than.the summit Of
Mt. Everest, In the Hmalayas, is above
it.
TEMPERATURE ON OCEAN. FLOOR.
Our knowledge of the temperature on
the floor of the ocean is derived from OBJ
servations In the layers Of water imme-
diately above the bottom by means Of
deep-sea thermometers, from the electric
resistance of telegraph cables resting on
the bed of the great ocean basins, and
from the temperature OF large masses Oh
mud and ooze brought up by the dredge
from great depths These observations
are now sufficiently numerous to permit
Of some general statements as 10 the
distribution of temperature over the bot
tom Of the great oceans All the tenn
peratures recorded up to the present time
In the subsurfaee waters Of the open
oceans indicate that at depth OF about
100 fathoms seasonal variation OF tenn
perature disappears. Beyond that deptn
there is a constant, or nearly constant,
temperature at any one place throughout
the year. -
1t Is estimated that 80 per cent OF the
entire sea flour has a temperature lower
than 40 degrees Fahrenheit. This Is IN
striking contrast to- the temperature pre-
vailing at the surface Of the ocean, only
16 per cent Of which has mean tempera-
ture under 40 degrees Fahrenheit. Inc
temperature over nearly the whole OF the
floor of the Indian ocean In deep water
Is under IS degrees Fahrenheit similar
temperature occurs over a large part OF
the South Atlantic and certain parts or
the Pacific; but at the bottom OF the
North Atlantic basin, and over very
large portion of the Pacific, the tenn
perature Is higher than degrees tanren-
heit. In depths beyond 1000 fathoms the
average temperature over the moor OF the
North Atlantic is about degrees Fahren-
heit above the average temperature at
the bottom of the Indian ocean and South
Atlantic, while the average temperature
of the bed of the Pacific is intermediate
between these.
A REGION OF DARKNESS.
The deep sea is region of darkness as
we'll as of low temperature, for the direct
rays OF the sun are wholly absorbed In
passing through the superficial layers OF
water Plant life is in consequence quite
absent over SO per cent of the bottom or
the ocean, or 66 per cert Of the whole
surface of the atmosphere. The abundant
deep sea fauna which covers the floor
of the ocean, is therefore ultimately DE-
pendent for food upon organic matter as
simulated by plants near Its surface, IN
the shallCwer waters near the coast
Ines and on the surface of the dry land
itself.
1t thus happens that at the present
time over nearly the whole floor of the
ocean we have mingled in the deposits
the remains Of organisms which had nved
under widely different physical condi-
tons, since the remains of organism
which have lived in tropical sunlight
and In water at temperature OF above
so degrees Fahrenheit all their lives now
lie buried In the same deposit on the sea
floor, together with the remains Of other
organisms which lived all their lives in
darkness and at temperature near to
the freezing point of fresh water The
marine deposits now forming over the
floor of the ocean present many interest
ing peculiarities, according to their geo
graphical and bathymetrical. position. ON
the continental shelf, within the 100
fathom line, sands and4 graVels ~predomi-
nate, while on the continental slopes be-
yond the 10O-fathom line blue muds, green
muds and red muds, together with vol
canfc mudS and coral muds prevail-the
two latter kinds Of deposits being, how
ever, more characteristic of the shallow
water around oceanic islands. The COM
position of all these terrigenous deposits
depends on the structure of the adjoining
chanica1 actions of tides of currents and
of great variety Of physical conditions
may almost everywhere be detected, and
1t is possible to5 recognize an accumula-
ton Of ma terials analogous to many Of
the marine stratified rocks Of the CONT
nents, such as sandstones, quantities.,
shales, nnarls, green sands, chalks lime
, stones, conglomerates and volcanic grits.
MARINE DEPOSITS.
With increasing depth and distance
from the continents the deposits grad
ually lose their terrigenous character
the particles. derived directly from the
emerged land decrease in size and in
number, the evidences of mechanical &C
| ton disappear, and the deposits pass
l. slowly into what have been called pelagic
| deposits at an average distance of about
| 200 miles from continental coast Tines.
Our knowledge Of the marine deposits is
limited to the superficial layers as rule
the sounding tube does not penetrate
more than six inches or eight inches but
in some positions the sounding tube and
dredge have been known to sink fully
two feet into the deposit. Sometimes
red clay Is overlaid by globigerina ooze,
more frequently a red clay .overlies a
globigerina ooze the transition between
two layers being either abrupt or gradual.
In some positions it is possible to account
for these layers by referring them to
changes in the condition of the surface
waters, but in other situations 1T seems
necessary to call in elevations and subs1-
dences of the sea floor. There Is a strik-
ing difference between the average chem
ical and meteorological composition, of
terrigenous and pelagic deposits. 1t would
be extremely interesting to have de-
tailed examination of one of those deep
holes where a typical red clay is present,
and even to bore some depth into such
a deposit, if possible, for In these posi-
TORS it is proba BILE that not more than a
few feet of deposit has accumulated since
the close Of the tertiary period. One such
area lies to the southwest of Australia,
and It's examination might possibly form
part of the programme of the approach
ing Antarctic explorations.
It has already been stated that plant
life is limited to the shallow waters, but