those relics of her operations which she has left behind. It is by the
population of the chalk sea that the ancient and the modern inhabitants
of the world are most completely connected. The groups which are dying
out flourish, side by side, with the groups which are now the dominant
forms of life. Thus the chalk contains remains of those strange flying
and swimming reptiles, the pterodactyl, the ichthyosaurus, and the
plesiosaurus, which are found in no later deposits, but abounded in
preceding ages. The chambered shells called ammonites and belemnites,
which are so characteristic of the period preceding the cretaceous, in
like manner die with it.

But, amongst these fading remainders of a previous state of things, are
some very modern forms of life, looking like Yankee pedlars among a tribe
of Red Indians. Crocodiles of modern type appear; bony fishes, many of
them very similar to existing species, almost supplant the forms of fish
which predominate in more ancient seas; and many kinds of living shell-
fish first become known to us in the chalk. The vegetation acquires a
modern aspect. A few living animals are not even distinguishable as
species, from those which existed at that remote epoch. The _Globigerina_
of the present day, for example, is not different specifically from that
of the chalk; and the same maybe said of many other _Foraminifera_. I
think it probable that critical and unprejudiced examination will show
that more than one species of much higher animals have had a similar
longevity; but the only example which I can at present give confidently
is the snake's-head lampshell (_Terebratulina caput serpentis_), which
lives in our English seas and abounded (as _Terebratulina striata_ of
authors) in the chalk.

The longest line of human ancestry must hide its diminished head before
the pedigree of this insignificant shell-fish. We Englishmen are proud to
have an ancestor who was present at the Battle of Hastings. The ancestors
of _Terebratulina caput serpentis_ may have been present at a battle of
_Ichthyosauria_ in that part of the sea which, when the chalk was
forming, flowed over the site of Hastings. While all around has changed,
this _Terebratulina_ has peacefully propagated its species from
generation to generation, and stands to this day, as a living testimony
to the continuity of the present with the past history of the globe.

Up to this moment I have stated, so far as I know, nothing but well-
a