ata, which have
become widely celebrated through the researches of Dr Falconer
and Sir Proby Cautley upon the numerous remains of Mammals and
Reptiles which they contain. Beds of corresponding age, with
similar fossils, are known to occur in the island of Perim in
the Gulf of Cambay.

Lastly, Miocene deposits are found in _North America_, in New
Jersey, Maryland, Virginia, Missouri, California, Oregon, &c.,
attaining a thickness of 1500 feet or more. They consist principally
of clays, sands, and sandstones, sometimes of marine and sometimes
of fresh-water origin. Near Richmond, in Virginia, there occurs a
remarkable stratum, wrongly called "Infusorial Earth," which is
occasionally 30 feet in thickness, and consists almost wholly of
the siliceous envelopes of certain low forms of plants (Diatoms),
along with the spicules of Sponges and other siliceous organisms
(see fig. 16). The _White River Group_ of Hayden occurs in the
Upper Missouri region, and is largely exposed over the barren
and desolate district known as the "Mauvaises Terres." They have
a thickness of 1000 feet or more, and contain numerous remains
of Mammals. They are of lacustrine origin, and are believed to
be of the age of the Lower Miocene. Upon the whole, about from
15 to 30 per cent of the _Mollusca_ of the American Miocene are
identical with existing species.

In addition to the regions previously enumerated, Miocene strata
are known to be developed in _Greenland, Iceland, Spitzbergen_,
and in other areas of less importance.

The _life_ of the Miocene period is extremely abundant, and, from
the nature of the deposits of this age, also extremely varied
in its character. The marine beds of the formation have yielded
numerous remains of both Vertebrate and Invertebrate sea-animals;
whilst the fresh-water deposits contain the skeletons of such
shells, fishes, &c., as now inhabit rivers or lakes. Both the
marine and the lacustrine beds have been shown to contain an
enormous number of plants, the latter more particularly; whilst
the Brown Coals of the formation are made up of vegetable matter
little altered from its original condition. The remains of
air-breathing animals, such as Insects, Reptiles, Birds, and
Mammals, are also abundantly found, more especially in the
fresh-water beds.

The _plants_ of the Miocene period are extraordinarily numerous,
and only some of the general features of the vegetation of this
epoch can be indicated here. Our chie