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 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 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 unmistakable 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.