Phascolarctos cinereus (Koalas). Image source: Gould, John. The Mammals of Australia. Vol. 1, London: Printed by Taylor and Francis, published by the author, 1863, pl. 14.

The Grandeur of Life

A Celebration of Charles Darwin and the Origin of Species

Section VI.

The Meaning of Fossils, 1720-1860

Discovery of the skull of the “Maastricht animal”. Image source: Faujas-de-St.-Fond, Barthélemy. Histoire naturelle de la Montagne de Saint-Pierre de Maestricht. Chez H.J. Jansen..., 1799, title page.

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In the Renaissance and early seventeenth century, it was generally believed that fossils were figured stones that grew in the rock, and were not the remains of once-living creatures. Robert Hooke and Nicolas Steno in the 1660s established that fossils were organic remains, but most of the fossils they dealt with were shells. It wasn’t until the eighteenth century that fossils of large quadrupeds, such as the mastodon and mammoth, began to be recognized. The central issue raised by such fossils was the question of extinction: were these species that had disappeared from the earth, or did they still survive in some form? Many opposed the possibility of extinction, because it seemed to imply that God’s creation was imperfect and incomplete. But Georges Cuvier in the early nineteenth century convincingly demonstrated that a whole host of animals had once populated the earth and were now extinct, having been wiped out by a succession of geological revolutions. By Darwin’s time, extinction was a well-recognized fact of nature. Cuvier, however, rejected evolution as a way of explaining extinction, as did most of his followers. Darwin would have a different view.