[Footnote 2: During the cruise of H.M.S. _Bulldog_, commanded by Sir
Leopold M'Clintock, in 1860, living star-fish were brought up, clinging
to the lowest part of the sounding-line, from a depth of 1,260 fathoms,
midway between Cape Farewell, in Greenland, and the Rockall banks. Dr.
Wallich ascertained that the sea-bottom at this point consisted of the
ordinary _Globigerina_ ooze, and that the stomachs of the star-fishes
were full of _Globigerinoe_. This discovery removes all objections to the
existence of living _Globigerinoe_ at great depths, which are based upon
the supposed difficulty of maintaining animal life under such conditions;
and it throws the burden of proof upon those who object to the
supposition that the _Globigerinoe_ live and die where they are found.]

However, the important points for us are, that the living _Globigerinoe_
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 _Globigerinoe_ 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 more
powder and waste of _Globigerinoe_, but that they had a definite form and
size. I termed these bodies "_coccoliths_," and doubted their organic
nature. Dr. Wallich verified my observation, and added the interesting
discovery that, not unfrequently, bodies similar to these "coccoliths"
were aggregated together into spheroids, which lie 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, 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 with
those in the Atlantic soundings, he found the two to be identical; and
thus proved that the chalk, like the surroundings, contains these
mysterious coccoliths and coccospheres. Here was a further and most
interesting confirmation, from internal evidence, of the essential
iden