wer
new red sandstone, and the magnesian limestone; (3) the Upper Trias,
composing the bunter, or variegated sandstone, the muschelkalk, and the
Keuper sandstone; (4) the Oolitic, or Jurassic series, including Lias;
(5) the Cretaceous series; (6) the Tertiary group, as represented in its
three stages by the _calcaire grossier_ and other beds of the Paris
basin, the lignites, or brown coal of Germany, and the sub-Apennine
group of Italy.

To these succeed transported soils (_alluvium_), containing the gigantic
bones of ancient mammalia, such as the mastodons, the dinotherium, and
the megatheroid animals, among which is the mylodon of Owen, an animal
upwards of eleven feet in length, allied to the sloth. Associated with
these extinct species are found the fossil remains of animals still
living: elephants, rhinoceroses, oxen, horses, and deer. Near Bogota, at
an elevation of 8,200 French feet above the level of the sea, there is a
field filled with the bones of mastodon (_Campo de Gigantes_), in which
I have had careful excavations made. The bones found on the table-lands
of Mexico belong to the true elephants of extinct species. The minor
range of the Himalaya, the Sewalik hills, contain, besides numerous
mastodons, the sivatherium and the gigantic land-tortoise
(_Colossochelys_), more than twelve feet in length and six in height, as
well as remains belonging to still existing species of elephants,
rhinoceroses, and giraffes. It is worthy of notice that these fossils
are found in a zone which enjoys the tropical climate supposed to have
prevailed at the period of the mastodons.

_V.--The Permanence of Science_

It has sometimes been regarded as a discouraging consideration that,
while works of literature being fast-rooted in the depths of human
feeling, imagination and reason suffer little from the lapse of time, it
is otherwise with works which treat of subjects dependent on the
progress of experimental knowledge. The improvement of instruments, and
the continued enlargement of the field of observation, render
investigations into natural phenomena and physical laws liable to become
antiquated, to lose their interest, and to cease to be read.

Let none who are deeply penetrated with a true and genuine love of
nature, and with a lively appreciation of the true charm and dignity of
the study of her laws, ever view with discouragement or regret that
which is connected with the enlargement of the boundaries of our
know