They are the shells of animals called Foraminifera, because the shells of some of them are full of holes, through which they put out tiny arms. So small they are and so many, that there may be, it is said, forty thousand of them in a bit of chalk an inch every way. In numbers past counting, some whole, some broken, some ground to the finest powder, they make up vast masses of England, which are now chalk downs; and in some foreign countries they make up whole mountains. Part of the building stone of the Great Pyramid in Egypt is composed, I am told, entirely of them.
And how did they get into the chalk?
Ah! How indeed? Let us think. The chalk must have been laid down at the bottom of a sea, because there are sea-shells in it. Besides, we find little atomies exactly like these alive now in many seas; and therefore it is fair to suppose these lived in the sea also.
Besides, they were not washed into the chalk by any sudden flood. The water in which they settled must have been quite still, or these little delicate creatures would have been ground into powder—or rather into paste. Therefore learned men soon made up their minds that these things were laid down at the bottom of a deep sea, so deep that neither wind, nor tide, nor currents could stir the everlasting calm.
Ah! it is worth thinking over, for it shows how shrewd a giant Analysis is, and how fast he works in these days, now that he has got free and well fed;—worth thinking over, I say, how our notions about these little atomies have changed during the last forty years.
We used to find them sometimes washed up among the sea-sand on the wild Atlantic coast; and we were taught, in the days when old Dr. Turton was writing his book on British shells at Bideford, to call them Nautili, because their shells were like Nautilus shells. Men did not know then that the animal which lives in them is no more like a Nautilus animal than it is like a cow.
For a Nautilus, you must know, is made like a cuttlefish, with eyes, and strong jaws for biting, and arms round them; and has a heart, and gills, and a stomach; and is altogether a very well-made beast, and, I suspect, a terrible tyrant to little fish and sea-slugs, just as the cuttlefish is. But the creatures which live in these little shells are about the least finished of Madam How’s works. They have neither mouth nor stomach, eyes nor limbs. They are mere live bags full of jelly, which can take almost any shape they like, and thrust out arms—or what serve for arms—through the holes in their shells, and then contract them into themselves again, as this Globigerina does. What they feed on, how they grow, how they make their exquisitely-formed shells, whether, indeed, they are, strictly speaking, animals or vegetables, Analysis has not yet found out. But when you come to read about them, you will find that they, in their own way, are just as wonderful and mysterious as a butterfly or a rose; and just as necessary, likewise, to Madam How’s work; for out of them, as I told you, she makes whole sheets of down, whole ranges of hills.
No one knew anything, I believe, about them, save that two or three kinds of them were found in chalk, till a famous Frenchman, called D’Orbigny, just thirty years ago, told the world how he had found many beautiful fresh kinds; and, more strange still, that some of these kinds were still alive at the bottom of the Adriatic, and of the harbour of Alexandria, in Egypt.
Then in 1841 a gentleman named Edward Forbes,—now with God—whose name will be for ever dear to all who love science, and honour genius and virtue,—found in the Ægean Sea “a bed of chalk,” he said, “full of Foraminifera, and shells of Pteropods,” forming at the bottom of the sea.
And what are Pteropods?