ghboring sea.

In this passing from the older to the newer members of the tertiary
system we meet with many chasms, but none which separate entirely, by a
broad line of demarcation, one state of the organic world from another.
There are no signs of an abrupt termination of one fauna and flora, and
the starting into life of new and wholly distinct forms. Although we are
far from being able to demonstrate geologically an insensible transition
from the Eocene to the Miocene, or even from the latter to the recent
fauna, yet the more we enlarge and perfect our general survey, the more
nearly do we approximate to such a continuous series, and the more
gradually are we conducted from times when many of the genera and nearly
all the species were extinct, to those in which scarcely a single
species flourished which we do not know to exist at present. Dr. A.
Philippi, indeed, after an elaborate comparison of the fossil tertiary
shells of Sicily with those now living in the Mediterranean, announces
as the result of his examination that there are strata in that island,
which attest a very gradual passage from a period, when only thirteen in
a hundred of the shells were like the species now living in the sea, to
an era when the recent species had attained a proportion of ninety-five
in a hundred. There is therefore evidence, he says, in Sicily of this
revolution in the animate world having been effected "without the
intervention of any convulsion or abrupt changes, certain species having
from time to time died out, and others having been introduced, until at
length the existing fauna was elaborated."

It had often been objected that the evidence of fossil species occurring
in two consecutive formations, was confined to the testacea or
zoophytes, the characters of which are less marked and decisive than
those afforded by the vertebrate animals. But Mr. Owen has lately
insisted on the important fact, that not a few of the quadrupeds which
now inhabit our island, and among others the horse, the ass, the hog,
the smaller wild ox, the goat, the red deer, the roe, the beaver, and
many of the diminutive rodents, are the same as those which once
coexisted with the mammoth, the great northern hippopotamus, two kinds
of rhinoceros, and other mammalia long since extinct. "A part," he
observes, "and not the whole of the modern tertiary fauna has perished,
and hence we may conclude that the cause of their destruction has not
been a violent and