The mighty deep

ONE of the tasks carried on in Ocean waters is Chalk-Building.

The “White Cliffs of Albion” and those also of Gaul are vast masses of chalk, containing layers of flint, and mixed with many other materials, but chiefly composed of the crumbling white substance, which is familiar to all who live near the North and South Downs.

This formation stretches a long way. The heights of Salisbury are of chalk. The Chiltern Hills are of chalk. The Yorkshire Wolds are of chalk. It is found in Norfolk; it is found in Kent; it is found in Surrey; it is found in Sussex. There are chalk-beds in France, in Germany, in other parts of Europe—not to speak of Asia—which, with those of Great Britain, extend through many hundreds of miles.

And wherever these masses of chalk are found, there we know that, once upon a time, the land lay under ocean-waves.

For Chalk, like Sandstone, was not formed on dry land. It could not be formed on dry land. It was built—it could only be built—under the sea, to be in later ages uplifted as dry land.

During those far-back days, when the chalk-beds of Europe were being made, a different state of things prevailed from that of the present. By far the greater part of Europe must have lain under water, from which the summits of the Alps, the Pyrenees, and other mountains emerged as groups of islands. Great Britain must have been chiefly or entirely hidden.

So far I have spoken of sandstone and chalk together. But a marked distinction—a vital distinction—exists between the two.

In the mode of their building they may be alike. In the materials of which they are built they are utterly different.

If a lump of chalk is examined by the chemist, its principal substance is found to be Carbonate of Lime.

Now there is something very remarkable about Carbonate of Lime. It is absolutely different from the materials of which sandstone and granite are made. Wherever we stumble upon carbonate-of-lime, there we are on the track of Life. And the moment that we touch upon Life, even in its simplest and lowest forms, we rise to a higher level.

Hitherto, in this subject of the Mighty Deep, we have had to do with things inanimate; things without consciousness; things blindly controlled by the forces of nature. In the story of ocean-waters, of ocean-salt, of ocean-rivers, of icebergs and ice-floes, Life has no part. There is no life in a grain of sand, no life in a granite rock.

But here, suddenly, we are arrested. Here, in the composition of Chalk, we come across a difference. Here, at one step, we pass over a vast dividing chasm, and stand face to face with that which has Life.

Not indeed that which lives now, but with that which did live, the signs of which may better help us to understand Life in the present.

Is this so new? Have we not already in former chapters found tokens of creatures which once existed, of fossil remains embedded in rock?

Yes; but that was not the same. Fossil remains are discovered in many kinds of stratified rock. Here we are not concerned with separate remains, buried in masses of chalk, but with the actual substance of chalk itself. The mere building of it, as earlier told, closely resembles the building of sandstone. Chalk, like sandstone, was formed in past ages out of tiny particles, carried by ocean-waves, dropped upon ocean’s bed, slowly consolidated, then gradually upheaved. Particles of——

Ah, there we reach the great distinction!

Not particles of inanimate mineral substances, such as grains of quartz. No; but particles which once formed the habitation of living creatures. More than this—particles which once shared in the Life of the beings with which for the time they were in touch. Infinitesimal specks, often so minute as to appear only as fine dust to man’s unaided sight; yet real organic remains, each one of which has been the home of an active animal.

A lump of chalk is a mass of densely packed tiny fossil shells, more or less crushed and broken. It has been reckoned that a cubic inch of chalk probably holds at least one million shells.

Try to imagine what this means. The work of the Ocean in building solid sandstone, from unnumbered myriads of myriads of grains of sand, is marvellous enough. But here we have something far more wonderful.

Here we have rocks and cliffs, ranges of hills and extents of country, to a great degree composed of almost invisible sea-shells, so small, so numerous, that a million or more of them may be packed into one little cubic inch of space, while the chalk-beds lie through hundreds of miles.

Think of continuous piles of these shells, many hundreds of feet in thickness, all built out of the dead shells of dying millions of tiny creatures. Deep, deep below the surface, where waves had no power, where currents were sluggish, fell a ceaseless gentle rain of these minute shells. Life had fled from each jelly inhabitant; its brief day was over; and the empty shell went quietly down, whether from near the surface or from lower depths, till it reached the ocean-bed. There it lay, forming part of a gathering sticky ooze or mud, which in later times should be slowly hardened into chalk.

But the greater wonder has yet to be told about these shells—these tiny highly-finished constructions.

Not only did a speck of living jelly once inhabit each shell. That speck of living jelly actually MADE the shell.

Not deliberately. Not with intention. Not even consciously. The “making” is in no sense to be confounded with voluntary effort, with the labour which means exertion and fatigue. It was as instinctive, as involuntary, as the “making” of bones in your body and mine.

“But we do not make our bones,” somebody may protest, with a touch of indignation.

Undoubtedly, in a sense, we do. The jelly-speck does not more surely “secrete” its shell, than a man “secretes” his skeleton. Personal will has not to do with the task in either case, beyond the taking in of necessary food; and neither man nor jelly-speck may claim any credit on the score of the pattern worked out.

We have all seen a garden-snail, carrying lightly upon its back its shell or “house,” or outside skeleton. That shell is formed of carbonate-of-lime. In the snail’s slimy body exists a small manufactory for producing or “secreting” carbonate-of-lime. The materials are obtained by the snail through its food. The deposits of it—made as the snail’s nature, certainly not the snail’s reason—dictates, grow into a sheltering framework for its protection.

In a Dictionary we may find the strict meaning of this word “secrete.” It is given as—“to hide; to conceal; to deposit in some secret or private place; to separate from the blood in animals, or from the sap in vegetables, and elaborate into a new product.”

One cannot deny that the word, though used for all such “elaborations,” is more appropriate in the case of a man’s hidden and private framework of bones, than in a snail’s or jelly-creature’s outside shell.

That which the garden-snail so deftly does, is done also by countless billions of minute jelly-specks in the ocean; though with the latter the mechanism is far simpler, because the animal belongs to a far lower and more primitive type.

Still, simple though the apparatus may be, the tiniest of these jelly-specks has power to separate lime from ocean-waters, to unite it with carbonic acid in its own frame, to form carbonate-of-lime from the two, and to build of the manufactured carbonate-of-lime a shell for its own use.

Thenceforward, for a little space, the jelly-speck lives in that shell, and feeds in that shell, and then it dies in that shell. When it exists no longer, down sinks the lifeless skeleton, to serve a new purpose at the bottom of the sea.

No mere shapeless lumps are these shells, flung together without care or plan. Each one, however infinitesimal in size, is a delicate and elaborate construction; each one shows the carrying out of a definite and beautiful plan. A different design serves for each species and kind of jelly-speck—not for each individual.

Such Design we must ascribe to a Mind lying beyond that which we see; not to the jelly-speck itself, which acts as an unconscious architect, working automatically, as you and I work in the early growth and later renewal of our bony frameworks, the “secreting” of our skeletons.

No chance tossing together of particles of carbonate-of-lime could result in the exquisite forms, the intricate patterns, of these little shells; still less, in such patterns being faithfully reproduced by millions of living jelly-specks, each according to its own class or variety.

For all this the present tense is as true as the past tense.

Those white cliffs along the coast were formed ages ago. But the ocean is working still, building still, piling grains of sand together still, heaping specks of mud together still, and laying shells, shells, shells, together still, in amounts beyond all reckoning.

Chalk-building went on in ages past; it goes on now; and doubtless it will go on in centuries to come.

Not only beyond reckoning, but beyond imagination, are the enormous multitudes of these creatures, which live and die in the ocean, forming their shells, and adding their skeletons to the ever-growing pile below.

Over a large part of the Atlantic bed, as over other Ocean-beds too, lies a thick ooze. When this was first brought to the surface, in soundings that were made before the laying of the earliest Atlantic cable, it was supposed to mean a thin deposit of no particular importance.

Then a deep-sea dredge, plunged into the ooze, carried away half-a-ton of it, and men began to realise what its presence might mean. By a long succession of soundings, its true nature became slowly manifest.

The ooze was found to be composed chiefly of tiny rounded shells, called “Globigerina,” which belong to a larger class, known as “Foraminifera.” And the white chalk of our British cliffs is made principally of Foraminifera shells.

This last name springs from two Latin words, meaning “I bear a hole.” The Foraminifera shells bear many holes. Each is in shape a tiny collection of rounded compartments, usually not more than sixteen in number; and each compartment has numerous minute holes in its walls.

Its inhabitant, a speck of jelly, is one of the least of living creatures, belonging to the great Division of “Protozoa,” or “First Animals.” None rank below them, for they are on the first or lowest rung in the ladder of life.

A jelly-speck has no head, no limbs, no stomach, not even a mouth. It can take in food at any part of its soft body. When it wishes—and apparently even a jelly-speck can wish, which at once separates it from inanimate materials—it makes a temporary tentacle or “foot,” by pushing out a slender filament of its own substance through one of the tiny holes in its shell. Whence the name “Rhizopod.”

Not all the Foraminifera specks live in the same kind of sheltering skeletons. Some construct delicate domes or many-chambered discs of sand-grains, joined together with enough carbonate-of-lime to act as building-cement. Such skeletons are called “tests,” to distinguish them from “shells” proper.

Hardly anything can be more remarkable than the way in which these tests are put together by mere specks of jelly, alive indeed, but without parts, without development, without understanding. How and why they should choose from one place, each the especial materials which go to form its own kind of “test,” is one of the mysteries in Nature for which Science has no explanation. We can but look and marvel.

One kind of jelly-speck will use the larger grains of quartz, arranging them, and joining them into a bottle-shaped test or shelter.

Another, in the same spot, belonging to a different species, will select tinier grains of the same substance, and will build out of them a rounded sphere, exquisitely modelled, with tiny holes at intervals for the protruding “limbs.”

Another, of yet a different species, picks out the minutest of sand-grains and of bits of sponge-spicules, and knits them together, without any cement, into delicate white globes, “like homœopathic globules,” giving to each a single opening.

And still another, of again a different species, forms a test of divers compartments, with a tiny doorway leading from each into the next.

Behind all these extraordinary constructions lies a Mind. But—not the mind of the jelly-speck!

Soft oozes, formed chiefly of Foraminifera and other shells, varying in size from a pin’s head to almost invisible specks—though some few kinds are larger—cover immense reaches of the ocean-bed, extending, it is said, over fifty millions of square miles.

Yet they are not found everywhere below the sea. Near to Continents, if they exist they are lost sight of amid the masses of sand and mud carried down from the land. And in the profounder abysses of the ocean they are lacking.

This last fact was long a puzzle. If the waters above were swarming with live Foraminifera, the dead shells of which must be ever pouring in a quiet rain to the ocean-bed, why should not the same ooze be found there, as elsewhere?

That the waters above, at least in all warmer climates, do swarm thus, is certain. Towards north and south, in colder seas, they rapidly lessen; but in tropical regions, and in warm ocean-streams their numbers are legion. Yet, from depths beyond about two miles, the ooze was not brought up.

One explanation can be given; and it is that of the strong dissolving power of sea-water. After a depth of about two miles, the delicate little shells fail to resist that power. Once at the bottom, they might be covered up and preserved; but they cease to exist en route thither.

So in this as in many other instances, we see opposite forces at work. The one force is perpetually undoing what the other force is perpetually doing. Innumerable multitudes of living creatures are at work, taking lime from the water, and constructing carbonate-of-lime. But the ocean is ever seeking to re-dissolve that carbonate-of-lime.

Another difficult question as to the ooze was—whether the shells of which it is mainly made were those of Foraminifera living in the deep sea, far down below the surface, or of Foraminifera living near the surface. Able men took both sides of the discussion, some ascribing the ooze entirely to deep-sea jelly-specks, others ascribing it entirely to surface jelly-specks.

The question cannot be said yet to have met with complete settlement. But here once more it seems that both sides have been partly in the right.

There are Foraminifera which live only at great depths, and there are Foraminifera which live only near the surface. The ooze is found to consist of shells belonging to both kinds, though it may be that the surface species carry away the palm in point of greater multitudes.