The Origin of Species Chapter 11 Part 2 - On the Geological Succession

In which the delicate and fragmentary nature of the geological record is shown to veil a slow but continual divergence of organic forms, linking extinct species as half-remembered echoes of their living descendants and revealing the gentle unfolding of modification through time. The successive faunas of the earth, though imperfectly preserved, betray a pattern of gradual change and succession that accords most naturally with the theory of descent by variation and natural selection.