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cable ＇64＇ between this country and the United States was undertaken。
For it became a matter of immense importance to know； not only the
depth of the sea over the whole line along which the cable was to
be laid； but the exact nature of the bottom； so as to guard against
chances of cutting or fraying the strands of that costly rope。 The
Admiralty consequently ordered Captain Dayman； an old friend and
shipmate of mine； to ascertain the depth over the whole line of the
cable； and to bring back specimens of the bottom。 In former days；
such a command as this might have sounded very much like one of the
impossible things which the young prince in the Fairy Tales is
ordered to do before he can obtain the hand of the Princess。
However； in the months of June and July； 1857； my friend performed
the task assigned to him with great expedition and precision
without； so far as I know； having met with any reward of that kind。
The specimens of Atlantic mud which he procured were sent to me to
be examined and reported upon。*
* See Appendix to Captain Dayman's 〃Deep…sea Soundings in the North
Atlantic Ocean； between Ireland and Newfoundland； made in H。M。S。
Cyclops。 Published by order of the Lords Commissioners of the
Admiralty； 1858。〃 They have since formed the subject of an
elaborate Memoir by Messrs。 Parker and Jones； published in the
Philosophical Transactions for 1865。
The result of all these operations is； that we know the contours
and the nature of the surface…soil covered by the North Atlantic；
for a distance of seventeen hundred miles from east to west； as
well as we know that of any part of the dry land。
It is a prodigious plainone of the widest and most even plains in
the world。 If the sea were drained off； you might drive a wagon
all the way from Valentia； on the west coast of Ireland； to Trinity
Bay； in Newfoundland。 And； except upon one sharp incline about two
hundred miles from Valentia； I am not quite sure that it would even
be necessary to put the skid on； so gentle are the ascents and
descents upon that long route。 From Valentia the road would lie
down…hill for about 200 miles to the point at which the bottom is
now covered by 1700 fathoms of sea…water。 Then would come the
central plain； more than a thousand miles wide； the inequalities of
the surface of which would be hardly perceptible； though the depth
of water upon it now varies from 10；000 to 15；000 feet； and there
are places in which Mont Blanc might be sunk without showing its
peak above water。 Beyond this； the ascent on the American side
commences； and gradually leads； for about 300 miles； to the
Newfoundland shore。
Almost the whole of the bottom of this central plain （which extends
for many hundred miles in a north and south direction） is covered
by a fine mud； which； when brought to the surface； dries into a
greyish…white friable substance。 You can write with this on a
blackboard； if you are so inclined； and； to the eye； it is quite
like very soft； greyish chalk。 Examined chemically； it proves to
be composed almost wholly of carbonate of lime； and if you make a
section of it； in the same way as that of the piece of chalk was
made； and view it with the microscope； it presents innumerable
Globigerinae embedded in a granular matrix。
Thus this deep…sea mud is substantially chalk。 I say
substantially； because there are a good many minor differences； but
as these have no bearing on the question immediately before us；
which is the nature of the Globigerinae of the chalk；it is
unnecessary to speak of them。
Globigerinae of every size； from the smallest to the largest； are
associated together in the Atlantic mud； and the chambers of many
are filled by a soft animal matter。 This soft substance is； in
fact； the remains of the creature to which the Globigerina shell；
or rather skeleton； owes its existenceand which is an animal of
the simplest imaginable description。 It is； in fact； a mere
particle of living jelly； without defined parts of any kind
without a mouth； nerves； muscles； or distinct organs； and only
manifesting its vitality to ordinary observation by thrusting out
and retracting from all parts of its surface； long filamentous
processes； which serve for arms and legs。 Yet this amorphous
particle； devoid of everything which； in the higher animals； we
call organs； is capable of feeding； growing and multiplying； of
separating from the ocean the small proportion of carbonate of lime
which is dissolved in sea…water； and of building up that substance
into a skeleton for itself； according to a pattern which can be
imitated by no other known agency。
The notion that animals can live and flourish in the sea； at the
vast depths from which apparently living Globigerinae have been
brought up； does not agree very well with our usual conceptions
respecting the conditions of animal life； and it is not so
absolutely impossible as it might at first appear to be； that the
Globigerinae of the Atlantic sea…bottom do not live and die where
they are found。
As I have mentioned； the soundings from the great Atlantic plain
are almost entirely made up of Globigerinae； with the granules
which have been mentioned and some few other calcareous shells； but
a small percentage of the chalky mudperhaps at most some five per
cent of itis of a different nature； and consists of shells and
skeletons composed of silex； or pure flint。 These silicious bodies
belong partly to the lowly vegetable organisms which are called
Diatomaceae； and partly to the minute； and extremely simple；
animals； termed Radiolaria。 It is quite certain that these
creatures do not live at the bottom of the ocean； but at its
surfacewhere they may be obtained in prodigious numbers by the
use of a properly constructed net。 Hence it follows that these
silicious organisms； though they are not heavier than the lightest
dust； must have fallen； in some cases； through fifteen thousand
feet of water； before they reached their final resting…place on the
ocean floor。 And； considering how large a surface these bodies
expose in proportion to their weight； it is probable that they
occupy a great length of time in making their burial journey from
the surface of the Atlantic to the bottom。
But if the Radiolaria and Diatoms are thus rained upon the bottom
of the sea； from the superficial layer of its waters in which they
pass their lives； it is obviously possible that the Globigerinae
may be similarly derived； and if they were so； it would be much
more easy to understand how they obtain their supply of food than
it is at present。 Nevertheless； the positive and negative evidence
all points the other way。 The skeletons of the full…grown； deep…
sea Globigerinae are so remarkably solid and heavy in proportion to
their surface as to seem little fitted for floating； and； as a
matter of fact； they are not to be found along with the Diatoms and
Radiolaria； in the uppermost stratum of the open ocean。
It has been observed； again； that the abundance of Globigerinae； in
proportion to other organisms； of like kind； increases with the
depth of the sea； and that deep…water Globigerinae are larger than
those which live in shallower parts of the sea； and such facts
negative the supposition that these organisms have been swept by
currents from the shallows into the deeps of the Atlantic。
It therefore seems to be hardly doubtful that these wonderful
creatures live and die at the depths in which they are found。
However； the important points for us are； that the living
Globigerinae are exclusively marine animals； the skeletons of which
abound at the bottom of deep seas； and that there is not a shadow
of reason for believing that the habits of the Globigerinae of the
chalk differed from those of the existing species。 But if this be
true； there is no escaping the conclusion that the chalk itself is
the dried mud of an ancient deep sea。
In working over the soundings collected by Captain Dayman； I was
surprised to find that many of what I have called the 〃granules〃 of
that mud； were not； as one might have been tempted to think at
first； the mere powder and waste of Globigerinae； but that they had
a definite form and size。 I termed these bodies 〃coccoliths；〃 and
doubted their organic nature。 Dr。 Wallich ＇65＇ verified my
observation； and added the interesting discovery； that； not
unfrequently； bodies similar to these 〃coccoliths〃 were aggregated
together into spheroids； which he termed 〃coccospheres。〃 So far
as we knew； these bodies； the nature of which is extremely puzzling
and problematical； were peculiar to the Atlantic soundings。
But； a few years ago； Mr。 Sorby；＇66＇ in making a careful examination
of the chalk by means of thin sections and otherwise； observed； as
Ehrenberg had done before him； that much of its granular basis
possesses a definite form。 Comparing these formed particles wit