y will partake of some inferiority in
common.

Thus, as it seems to me, the manner in which single species and whole
groups of species become extinct, accords well with the theory of natural
selection. We need not marvel at extinction; if we must marvel, let it be
at our presumption in imagining for a moment that we understand the many
complex contingencies, on which the existence of each species depends. If
we forget for an instant, that each species tends to increase inordinately,
and that some check is always in action, yet seldom perceived by us, the
whole economy of nature will be utterly obscured. Whenever we can precisely
say why this species is more abundant in individuals than that; why this
species and not another can be naturalised in a given country; then, and
not till then, we may justly feel surprise why we cannot account for the
extinction of this particular species or group of species.

_On the Forms of Life changing almost simultaneously throughout the
World._--Scarcely any palaeontological discovery is more striking than the
fact, that the forms of life change almost simultaneously throughout the
world. Thus our European Chalk formation can be recognised in many distant
parts of the world, under the most different climates, where not a fragment
of the mineral chalk itself can be found; namely, in North {323} America,
in equatorial South America, in Tierra del Fuego, at the Cape of Good Hope,
and in the peninsula of India. For at these distant points, the organic
remains in certain beds present an unmistakeable degree of resemblance to
those of the Chalk. It is not that the same species are met with; for in
some cases not one species is identically the same, but they belong to the
same families, genera, and sections of genera, and sometimes are similarly
characterised in such trifling points as mere superficial sculpture.
Moreover other forms, which are not found in the Chalk of Europe, but which
occur in the formations either above or below, are similarly absent at
these distant points of the world. In the several successive palaeozoic
formations of Russia, Western Europe and North America, a similar
parallelism in the forms of life has been observed by several authors: so
it is, according to Lyell, with the several European and North American
tertiary deposits. Even if the few fossil species which are common to the
Old and New Worlds be kept wholly out of view, the general parallelism in
the succe