56
THE SEAS
J
The vast bulk of life in the open sea is composed,
not of
‘
large and active creatures, such as sh or whales, but of
microscopic plants and animals which drift near the
surface and make up the all-important plankton.
It is
-
their skeletons which
the great proportion of the deep-‘
sea
depoSits, for their bodies soon disintegrate or are
eateu by other animals.
From their consistency Murray
called these deep—sea deposits Oozes, and distinguished them
'
accordingto the complete absence or relative abundance of
..
the various kinds ot skeletons.
-
.
Particularly around the poles, in \the Antarctic ocean
,
.
.
especially, the surface waters contain vast numbers of the
'_
microscopic plants called diatoms, each individual of which
’
is enclosed in a delicate case of silica, and it is these minute
plant
“
skeletons ” which form the chief constituent of the
'
'
deposits in these regions, hence called diatom ooze.
Al—
though there is an abundant ora in the temperate and
,
tropic seas, there is a larger proportion of animals, those
with calcareoùs‘ shells being the cdmmonest.
Chief among
these are the tiny ‘foraminifera of which one called Globi—
germa is the most plentiful, and ooze, with its limy
skeletons as the principal constituent (Plate 21), is extremely
widespread»cov<èring an estimated area of some 48,ooo,ooo
_
square miles, being especially abundarit in the
'
»
A
of deposit which is really only a variety of the
last'is called Pteropod ooze; it takes its name from the
predominanæ in it of the limy skeletons of delicate swim—
ming‘snàils known as 'Pteropods or “'sea Butteries ” which
.
near the equator where this type of ooze is
exclusively found, always in shallower water than Globigerina ooze and especially near coral islands and on Submerged elevations
from land.
'
Beneatha certain depth oozes with limÿ shells as their
principal constituent are -no longer found, a11 calcaœous
l
-
.
'
THE SEAS
J
The vast bulk of life in the open sea is composed,
not of
‘
large and active creatures, such as sh or whales, but of
microscopic plants and animals which drift near the
surface and make up the all-important plankton.
It is
-
their skeletons which
the great proportion of the deep-‘
sea
depoSits, for their bodies soon disintegrate or are
eateu by other animals.
From their consistency Murray
called these deep—sea deposits Oozes, and distinguished them
'
accordingto the complete absence or relative abundance of
..
the various kinds ot skeletons.
-
.
Particularly around the poles, in \the Antarctic ocean
,
.
.
especially, the surface waters contain vast numbers of the
'_
microscopic plants called diatoms, each individual of which
’
is enclosed in a delicate case of silica, and it is these minute
plant
“
skeletons ” which form the chief constituent of the
'
'
deposits in these regions, hence called diatom ooze.
Al—
though there is an abundant ora in the temperate and
,
tropic seas, there is a larger proportion of animals, those
with calcareoùs‘ shells being the cdmmonest.
Chief among
these are the tiny ‘foraminifera of which one called Globi—
germa is the most plentiful, and ooze, with its limy
skeletons as the principal constituent (Plate 21), is extremely
widespread»cov<èring an estimated area of some 48,ooo,ooo
_
square miles, being especially abundarit in the
'
»
A
of deposit which is really only a variety of the
last'is called Pteropod ooze; it takes its name from the
predominanæ in it of the limy skeletons of delicate swim—
ming‘snàils known as 'Pteropods or “'sea Butteries ” which
.
near the equator where this type of ooze is
exclusively found, always in shallower water than Globigerina ooze and especially near coral islands and on Submerged elevations
from land.
'
Beneatha certain depth oozes with limÿ shells as their
principal constituent are -no longer found, a11 calcaœous
l
-
.
'