Eocene testacea, and of which a large
proportion, although a minority of the whole number, are recent, besides
many corals, echini, foraminifera, and fish, but as yet no relic
decidedly mammalian except the ear-bone of a whale.

In the shelly sand, provincially termed "Red Crag," in Suffolk, which
immediately succeeds the coralline, constituting a newer member of the
same tertiary group, about 250 species of shells have been recognized,
of which a still larger proportion are recent. They are associated with
numerous teeth of fish; but no signs of a warm-blooded quadruped had
been detected until 1839, when the teeth of a leopard, a bear, a hog,
and a species of ruminant, were found at Newbourn, in Suffolk, and since
that time, several other genera of mammalia have been met with in the
same formation, or in the Red Crag.[223]

Of a still newer date is the Norwich Crag, a fluvio-marine deposit of
the Pleiocene epoch, containing a mixture of marine, fluviatile, and
land shells, of which 90 per cent. or more are recent. These beds,
since the time of their first investigation, have yielded a supply of
mammalian bones of the genera mastodon, elephant, rhinoceros, pig,
horse, deer, ox, and others, the bodies of which may have been washed
down into the sea by rivers draining land, of which the contiguity is
indicated by the occasional presence of terrestrial and freshwater
shells.

Our acquaintance with the newer Pleiocene mammalia in Europe, South
America, and Australia, is derived chiefly from cavern deposits, a fact
which we ought never to forget if we desire to appreciate the superior
facilities we enjoy for studying the more modern as compared to the more
ancient terrestrial faunas. We know nothing of the fossil bones which
must have been inclosed in the stalagmite of caverns in the older
Pleiocene, or in the Miocene or Eocene epochs, much less can we derive
any information respecting the inhabitants of the land from a similar
source, when we carry back our inquiries to the Wealden or carboniferous
epochs. We are as well assured that land and rivers then existed, as
that they exist now; but it is evident that even a slight geographical
revolution, accompanied by the submergence and denudation of land, would
reduce to an extreme improbability the chance of our hitting on those
minute points of space where caves may once have occurred in limestone
rocks.

_Fossil quadrumana._--Until within a few years (1836, 1837), not a