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.