Page - 373 - in The Origin of Species

FORMS OF LIFE CHANGING 373 a given country; then, and not until then, we may justly feci surprise why we cannot account for the extinction of any particular species or group of species. ON THE FORMS OF LIFE CHANGING ALMOST SIMULTANE- OUSLY THROUGHOUT THE WORLD Scarcely any palseontological discovery is more striking than the fact that the forms of life change almost simulta- neously throughout the world. Thus our European Chalk formation can be recognised in many distinct regions, under the most different climates, where not a fragment of the mineral chalk itself can be found; namely in North America, in equatorial South America, in Ticrra 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 pre- sent an unmistakeable 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 forma- tions either above or below, occur in the same order at these distant points of the world. In the several successive palaeo- zoic 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 European and North American tertiary deposits. Even if the few fossil species which are common to the Old and New Worlds were kept wholly out of view, the general par- allelism in the successive forms of life, in the palaeozoic and tertiary stages, would still be manifest, and the several for- mations could be easily correlated. These observations, however, relate to the marine inhabi- tants of the world: we have not sufficient data to judge whether the productions of the land and of fresh water at distant points change in the same parallel manner. We may doubt whether they have thus changed: if the Megatherium, Mylodon, Macrauchenia, and Toxodon had been brought to