ottom is now
covered by I,700 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, tho 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 grayish-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, grayish 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 imbedded 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 existence, and 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